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TOMOYO Linux Cross Reference
Linux/net/sctp/sm_statefuns.c

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  1 // SPDX-License-Identifier: GPL-2.0-or-later
  2 /* SCTP kernel implementation
  3  * (C) Copyright IBM Corp. 2001, 2004
  4  * Copyright (c) 1999-2000 Cisco, Inc.
  5  * Copyright (c) 1999-2001 Motorola, Inc.
  6  * Copyright (c) 2001-2002 Intel Corp.
  7  * Copyright (c) 2002      Nokia Corp.
  8  *
  9  * This is part of the SCTP Linux Kernel Implementation.
 10  *
 11  * These are the state functions for the state machine.
 12  *
 13  * Please send any bug reports or fixes you make to the
 14  * email address(es):
 15  *    lksctp developers <linux-sctp@vger.kernel.org>
 16  *
 17  * Written or modified by:
 18  *    La Monte H.P. Yarroll <piggy@acm.org>
 19  *    Karl Knutson          <karl@athena.chicago.il.us>
 20  *    Mathew Kotowsky       <kotowsky@sctp.org>
 21  *    Sridhar Samudrala     <samudrala@us.ibm.com>
 22  *    Jon Grimm             <jgrimm@us.ibm.com>
 23  *    Hui Huang             <hui.huang@nokia.com>
 24  *    Dajiang Zhang         <dajiang.zhang@nokia.com>
 25  *    Daisy Chang           <daisyc@us.ibm.com>
 26  *    Ardelle Fan           <ardelle.fan@intel.com>
 27  *    Ryan Layer            <rmlayer@us.ibm.com>
 28  *    Kevin Gao             <kevin.gao@intel.com>
 29  */
 30 
 31 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 32 
 33 #include <linux/types.h>
 34 #include <linux/kernel.h>
 35 #include <linux/ip.h>
 36 #include <linux/ipv6.h>
 37 #include <linux/net.h>
 38 #include <linux/inet.h>
 39 #include <linux/slab.h>
 40 #include <net/sock.h>
 41 #include <net/proto_memory.h>
 42 #include <net/inet_ecn.h>
 43 #include <linux/skbuff.h>
 44 #include <net/sctp/sctp.h>
 45 #include <net/sctp/sm.h>
 46 #include <net/sctp/structs.h>
 47 
 48 #define CREATE_TRACE_POINTS
 49 #include <trace/events/sctp.h>
 50 
 51 static struct sctp_packet *sctp_abort_pkt_new(
 52                                         struct net *net,
 53                                         const struct sctp_endpoint *ep,
 54                                         const struct sctp_association *asoc,
 55                                         struct sctp_chunk *chunk,
 56                                         const void *payload, size_t paylen);
 57 static int sctp_eat_data(const struct sctp_association *asoc,
 58                          struct sctp_chunk *chunk,
 59                          struct sctp_cmd_seq *commands);
 60 static struct sctp_packet *sctp_ootb_pkt_new(
 61                                         struct net *net,
 62                                         const struct sctp_association *asoc,
 63                                         const struct sctp_chunk *chunk);
 64 static void sctp_send_stale_cookie_err(struct net *net,
 65                                        const struct sctp_endpoint *ep,
 66                                        const struct sctp_association *asoc,
 67                                        const struct sctp_chunk *chunk,
 68                                        struct sctp_cmd_seq *commands,
 69                                        struct sctp_chunk *err_chunk);
 70 static enum sctp_disposition sctp_sf_do_5_2_6_stale(
 71                                         struct net *net,
 72                                         const struct sctp_endpoint *ep,
 73                                         const struct sctp_association *asoc,
 74                                         const union sctp_subtype type,
 75                                         void *arg,
 76                                         struct sctp_cmd_seq *commands);
 77 static enum sctp_disposition sctp_sf_shut_8_4_5(
 78                                         struct net *net,
 79                                         const struct sctp_endpoint *ep,
 80                                         const struct sctp_association *asoc,
 81                                         const union sctp_subtype type,
 82                                         void *arg,
 83                                         struct sctp_cmd_seq *commands);
 84 static enum sctp_disposition sctp_sf_tabort_8_4_8(
 85                                         struct net *net,
 86                                         const struct sctp_endpoint *ep,
 87                                         const struct sctp_association *asoc,
 88                                         const union sctp_subtype type,
 89                                         void *arg,
 90                                         struct sctp_cmd_seq *commands);
 91 static enum sctp_disposition sctp_sf_new_encap_port(
 92                                         struct net *net,
 93                                         const struct sctp_endpoint *ep,
 94                                         const struct sctp_association *asoc,
 95                                         const union sctp_subtype type,
 96                                         void *arg,
 97                                         struct sctp_cmd_seq *commands);
 98 static struct sctp_sackhdr *sctp_sm_pull_sack(struct sctp_chunk *chunk);
 99 
100 static enum sctp_disposition sctp_stop_t1_and_abort(
101                                         struct net *net,
102                                         struct sctp_cmd_seq *commands,
103                                         __be16 error, int sk_err,
104                                         const struct sctp_association *asoc,
105                                         struct sctp_transport *transport);
106 
107 static enum sctp_disposition sctp_sf_abort_violation(
108                                         struct net *net,
109                                         const struct sctp_endpoint *ep,
110                                         const struct sctp_association *asoc,
111                                         void *arg,
112                                         struct sctp_cmd_seq *commands,
113                                         const __u8 *payload,
114                                         const size_t paylen);
115 
116 static enum sctp_disposition sctp_sf_violation_chunklen(
117                                         struct net *net,
118                                         const struct sctp_endpoint *ep,
119                                         const struct sctp_association *asoc,
120                                         const union sctp_subtype type,
121                                         void *arg,
122                                         struct sctp_cmd_seq *commands);
123 
124 static enum sctp_disposition sctp_sf_violation_paramlen(
125                                         struct net *net,
126                                         const struct sctp_endpoint *ep,
127                                         const struct sctp_association *asoc,
128                                         const union sctp_subtype type,
129                                         void *arg, void *ext,
130                                         struct sctp_cmd_seq *commands);
131 
132 static enum sctp_disposition sctp_sf_violation_ctsn(
133                                         struct net *net,
134                                         const struct sctp_endpoint *ep,
135                                         const struct sctp_association *asoc,
136                                         const union sctp_subtype type,
137                                         void *arg,
138                                         struct sctp_cmd_seq *commands);
139 
140 static enum sctp_disposition sctp_sf_violation_chunk(
141                                         struct net *net,
142                                         const struct sctp_endpoint *ep,
143                                         const struct sctp_association *asoc,
144                                         const union sctp_subtype type,
145                                         void *arg,
146                                         struct sctp_cmd_seq *commands);
147 
148 static enum sctp_ierror sctp_sf_authenticate(
149                                         const struct sctp_association *asoc,
150                                         struct sctp_chunk *chunk);
151 
152 static enum sctp_disposition __sctp_sf_do_9_1_abort(
153                                         struct net *net,
154                                         const struct sctp_endpoint *ep,
155                                         const struct sctp_association *asoc,
156                                         const union sctp_subtype type,
157                                         void *arg,
158                                         struct sctp_cmd_seq *commands);
159 
160 static enum sctp_disposition
161 __sctp_sf_do_9_2_reshutack(struct net *net, const struct sctp_endpoint *ep,
162                            const struct sctp_association *asoc,
163                            const union sctp_subtype type, void *arg,
164                            struct sctp_cmd_seq *commands);
165 
166 /* Small helper function that checks if the chunk length
167  * is of the appropriate length.  The 'required_length' argument
168  * is set to be the size of a specific chunk we are testing.
169  * Return Values:  true  = Valid length
170  *                 false = Invalid length
171  *
172  */
173 static inline bool sctp_chunk_length_valid(struct sctp_chunk *chunk,
174                                            __u16 required_length)
175 {
176         __u16 chunk_length = ntohs(chunk->chunk_hdr->length);
177 
178         /* Previously already marked? */
179         if (unlikely(chunk->pdiscard))
180                 return false;
181         if (unlikely(chunk_length < required_length))
182                 return false;
183 
184         return true;
185 }
186 
187 /* Check for format error in an ABORT chunk */
188 static inline bool sctp_err_chunk_valid(struct sctp_chunk *chunk)
189 {
190         struct sctp_errhdr *err;
191 
192         sctp_walk_errors(err, chunk->chunk_hdr);
193 
194         return (void *)err == (void *)chunk->chunk_end;
195 }
196 
197 /**********************************************************
198  * These are the state functions for handling chunk events.
199  **********************************************************/
200 
201 /*
202  * Process the final SHUTDOWN COMPLETE.
203  *
204  * Section: 4 (C) (diagram), 9.2
205  * Upon reception of the SHUTDOWN COMPLETE chunk the endpoint will verify
206  * that it is in SHUTDOWN-ACK-SENT state, if it is not the chunk should be
207  * discarded. If the endpoint is in the SHUTDOWN-ACK-SENT state the endpoint
208  * should stop the T2-shutdown timer and remove all knowledge of the
209  * association (and thus the association enters the CLOSED state).
210  *
211  * Verification Tag: 8.5.1(C), sctpimpguide 2.41.
212  * C) Rules for packet carrying SHUTDOWN COMPLETE:
213  * ...
214  * - The receiver of a SHUTDOWN COMPLETE shall accept the packet
215  *   if the Verification Tag field of the packet matches its own tag and
216  *   the T bit is not set
217  *   OR
218  *   it is set to its peer's tag and the T bit is set in the Chunk
219  *   Flags.
220  *   Otherwise, the receiver MUST silently discard the packet
221  *   and take no further action.  An endpoint MUST ignore the
222  *   SHUTDOWN COMPLETE if it is not in the SHUTDOWN-ACK-SENT state.
223  *
224  * Inputs
225  * (endpoint, asoc, chunk)
226  *
227  * Outputs
228  * (asoc, reply_msg, msg_up, timers, counters)
229  *
230  * The return value is the disposition of the chunk.
231  */
232 enum sctp_disposition sctp_sf_do_4_C(struct net *net,
233                                      const struct sctp_endpoint *ep,
234                                      const struct sctp_association *asoc,
235                                      const union sctp_subtype type,
236                                      void *arg, struct sctp_cmd_seq *commands)
237 {
238         struct sctp_chunk *chunk = arg;
239         struct sctp_ulpevent *ev;
240 
241         if (!sctp_vtag_verify_either(chunk, asoc))
242                 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
243 
244         /* RFC 2960 6.10 Bundling
245          *
246          * An endpoint MUST NOT bundle INIT, INIT ACK or
247          * SHUTDOWN COMPLETE with any other chunks.
248          */
249         if (!chunk->singleton)
250                 return sctp_sf_violation_chunk(net, ep, asoc, type, arg, commands);
251 
252         /* Make sure that the SHUTDOWN_COMPLETE chunk has a valid length. */
253         if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr)))
254                 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
255                                                   commands);
256 
257         /* RFC 2960 10.2 SCTP-to-ULP
258          *
259          * H) SHUTDOWN COMPLETE notification
260          *
261          * When SCTP completes the shutdown procedures (section 9.2) this
262          * notification is passed to the upper layer.
263          */
264         ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_SHUTDOWN_COMP,
265                                              0, 0, 0, NULL, GFP_ATOMIC);
266         if (ev)
267                 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
268                                 SCTP_ULPEVENT(ev));
269 
270         /* Upon reception of the SHUTDOWN COMPLETE chunk the endpoint
271          * will verify that it is in SHUTDOWN-ACK-SENT state, if it is
272          * not the chunk should be discarded. If the endpoint is in
273          * the SHUTDOWN-ACK-SENT state the endpoint should stop the
274          * T2-shutdown timer and remove all knowledge of the
275          * association (and thus the association enters the CLOSED
276          * state).
277          */
278         sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
279                         SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
280 
281         sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
282                         SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
283 
284         sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
285                         SCTP_STATE(SCTP_STATE_CLOSED));
286 
287         SCTP_INC_STATS(net, SCTP_MIB_SHUTDOWNS);
288         SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
289 
290         sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
291 
292         return SCTP_DISPOSITION_DELETE_TCB;
293 }
294 
295 /*
296  * Respond to a normal INIT chunk.
297  * We are the side that is being asked for an association.
298  *
299  * Section: 5.1 Normal Establishment of an Association, B
300  * B) "Z" shall respond immediately with an INIT ACK chunk.  The
301  *    destination IP address of the INIT ACK MUST be set to the source
302  *    IP address of the INIT to which this INIT ACK is responding.  In
303  *    the response, besides filling in other parameters, "Z" must set the
304  *    Verification Tag field to Tag_A, and also provide its own
305  *    Verification Tag (Tag_Z) in the Initiate Tag field.
306  *
307  * Verification Tag: Must be 0.
308  *
309  * Inputs
310  * (endpoint, asoc, chunk)
311  *
312  * Outputs
313  * (asoc, reply_msg, msg_up, timers, counters)
314  *
315  * The return value is the disposition of the chunk.
316  */
317 enum sctp_disposition sctp_sf_do_5_1B_init(struct net *net,
318                                            const struct sctp_endpoint *ep,
319                                            const struct sctp_association *asoc,
320                                            const union sctp_subtype type,
321                                            void *arg,
322                                            struct sctp_cmd_seq *commands)
323 {
324         struct sctp_chunk *chunk = arg, *repl, *err_chunk;
325         struct sctp_unrecognized_param *unk_param;
326         struct sctp_association *new_asoc;
327         struct sctp_packet *packet;
328         int len;
329 
330         /* 6.10 Bundling
331          * An endpoint MUST NOT bundle INIT, INIT ACK or
332          * SHUTDOWN COMPLETE with any other chunks.
333          *
334          * IG Section 2.11.2
335          * Furthermore, we require that the receiver of an INIT chunk MUST
336          * enforce these rules by silently discarding an arriving packet
337          * with an INIT chunk that is bundled with other chunks.
338          */
339         if (!chunk->singleton)
340                 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
341 
342         /* Make sure that the INIT chunk has a valid length.
343          * Normally, this would cause an ABORT with a Protocol Violation
344          * error, but since we don't have an association, we'll
345          * just discard the packet.
346          */
347         if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_init_chunk)))
348                 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
349 
350         /* If the packet is an OOTB packet which is temporarily on the
351          * control endpoint, respond with an ABORT.
352          */
353         if (ep == sctp_sk(net->sctp.ctl_sock)->ep) {
354                 SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES);
355                 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands);
356         }
357 
358         /* 3.1 A packet containing an INIT chunk MUST have a zero Verification
359          * Tag.
360          */
361         if (chunk->sctp_hdr->vtag != 0)
362                 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands);
363 
364         /* If the INIT is coming toward a closing socket, we'll send back
365          * and ABORT.  Essentially, this catches the race of INIT being
366          * backloged to the socket at the same time as the user issues close().
367          * Since the socket and all its associations are going away, we
368          * can treat this OOTB
369          */
370         if (sctp_sstate(ep->base.sk, CLOSING))
371                 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands);
372 
373         /* Verify the INIT chunk before processing it. */
374         err_chunk = NULL;
375         if (!sctp_verify_init(net, ep, asoc, chunk->chunk_hdr->type,
376                               (struct sctp_init_chunk *)chunk->chunk_hdr, chunk,
377                               &err_chunk)) {
378                 /* This chunk contains fatal error. It is to be discarded.
379                  * Send an ABORT, with causes if there is any.
380                  */
381                 if (err_chunk) {
382                         packet = sctp_abort_pkt_new(net, ep, asoc, arg,
383                                         (__u8 *)(err_chunk->chunk_hdr) +
384                                         sizeof(struct sctp_chunkhdr),
385                                         ntohs(err_chunk->chunk_hdr->length) -
386                                         sizeof(struct sctp_chunkhdr));
387 
388                         sctp_chunk_free(err_chunk);
389 
390                         if (packet) {
391                                 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
392                                                 SCTP_PACKET(packet));
393                                 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
394                                 return SCTP_DISPOSITION_CONSUME;
395                         } else {
396                                 return SCTP_DISPOSITION_NOMEM;
397                         }
398                 } else {
399                         return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg,
400                                                     commands);
401                 }
402         }
403 
404         /* Grab the INIT header.  */
405         chunk->subh.init_hdr = (struct sctp_inithdr *)chunk->skb->data;
406 
407         /* Tag the variable length parameters.  */
408         chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(struct sctp_inithdr));
409 
410         new_asoc = sctp_make_temp_asoc(ep, chunk, GFP_ATOMIC);
411         if (!new_asoc)
412                 goto nomem;
413 
414         /* Update socket peer label if first association. */
415         if (security_sctp_assoc_request(new_asoc, chunk->skb)) {
416                 sctp_association_free(new_asoc);
417                 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
418         }
419 
420         if (sctp_assoc_set_bind_addr_from_ep(new_asoc,
421                                              sctp_scope(sctp_source(chunk)),
422                                              GFP_ATOMIC) < 0)
423                 goto nomem_init;
424 
425         /* The call, sctp_process_init(), can fail on memory allocation.  */
426         if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk),
427                                (struct sctp_init_chunk *)chunk->chunk_hdr,
428                                GFP_ATOMIC))
429                 goto nomem_init;
430 
431         /* B) "Z" shall respond immediately with an INIT ACK chunk.  */
432 
433         /* If there are errors need to be reported for unknown parameters,
434          * make sure to reserve enough room in the INIT ACK for them.
435          */
436         len = 0;
437         if (err_chunk)
438                 len = ntohs(err_chunk->chunk_hdr->length) -
439                       sizeof(struct sctp_chunkhdr);
440 
441         repl = sctp_make_init_ack(new_asoc, chunk, GFP_ATOMIC, len);
442         if (!repl)
443                 goto nomem_init;
444 
445         /* If there are errors need to be reported for unknown parameters,
446          * include them in the outgoing INIT ACK as "Unrecognized parameter"
447          * parameter.
448          */
449         if (err_chunk) {
450                 /* Get the "Unrecognized parameter" parameter(s) out of the
451                  * ERROR chunk generated by sctp_verify_init(). Since the
452                  * error cause code for "unknown parameter" and the
453                  * "Unrecognized parameter" type is the same, we can
454                  * construct the parameters in INIT ACK by copying the
455                  * ERROR causes over.
456                  */
457                 unk_param = (struct sctp_unrecognized_param *)
458                             ((__u8 *)(err_chunk->chunk_hdr) +
459                             sizeof(struct sctp_chunkhdr));
460                 /* Replace the cause code with the "Unrecognized parameter"
461                  * parameter type.
462                  */
463                 sctp_addto_chunk(repl, len, unk_param);
464                 sctp_chunk_free(err_chunk);
465         }
466 
467         sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc));
468 
469         sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
470 
471         /*
472          * Note:  After sending out INIT ACK with the State Cookie parameter,
473          * "Z" MUST NOT allocate any resources, nor keep any states for the
474          * new association.  Otherwise, "Z" will be vulnerable to resource
475          * attacks.
476          */
477         sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
478 
479         return SCTP_DISPOSITION_DELETE_TCB;
480 
481 nomem_init:
482         sctp_association_free(new_asoc);
483 nomem:
484         if (err_chunk)
485                 sctp_chunk_free(err_chunk);
486         return SCTP_DISPOSITION_NOMEM;
487 }
488 
489 /*
490  * Respond to a normal INIT ACK chunk.
491  * We are the side that is initiating the association.
492  *
493  * Section: 5.1 Normal Establishment of an Association, C
494  * C) Upon reception of the INIT ACK from "Z", "A" shall stop the T1-init
495  *    timer and leave COOKIE-WAIT state. "A" shall then send the State
496  *    Cookie received in the INIT ACK chunk in a COOKIE ECHO chunk, start
497  *    the T1-cookie timer, and enter the COOKIE-ECHOED state.
498  *
499  *    Note: The COOKIE ECHO chunk can be bundled with any pending outbound
500  *    DATA chunks, but it MUST be the first chunk in the packet and
501  *    until the COOKIE ACK is returned the sender MUST NOT send any
502  *    other packets to the peer.
503  *
504  * Verification Tag: 3.3.3
505  *   If the value of the Initiate Tag in a received INIT ACK chunk is
506  *   found to be 0, the receiver MUST treat it as an error and close the
507  *   association by transmitting an ABORT.
508  *
509  * Inputs
510  * (endpoint, asoc, chunk)
511  *
512  * Outputs
513  * (asoc, reply_msg, msg_up, timers, counters)
514  *
515  * The return value is the disposition of the chunk.
516  */
517 enum sctp_disposition sctp_sf_do_5_1C_ack(struct net *net,
518                                           const struct sctp_endpoint *ep,
519                                           const struct sctp_association *asoc,
520                                           const union sctp_subtype type,
521                                           void *arg,
522                                           struct sctp_cmd_seq *commands)
523 {
524         struct sctp_init_chunk *initchunk;
525         struct sctp_chunk *chunk = arg;
526         struct sctp_chunk *err_chunk;
527         struct sctp_packet *packet;
528 
529         if (!sctp_vtag_verify(chunk, asoc))
530                 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
531 
532         /* 6.10 Bundling
533          * An endpoint MUST NOT bundle INIT, INIT ACK or
534          * SHUTDOWN COMPLETE with any other chunks.
535          */
536         if (!chunk->singleton)
537                 return sctp_sf_violation_chunk(net, ep, asoc, type, arg, commands);
538 
539         /* Make sure that the INIT-ACK chunk has a valid length */
540         if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_initack_chunk)))
541                 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
542                                                   commands);
543         /* Grab the INIT header.  */
544         chunk->subh.init_hdr = (struct sctp_inithdr *)chunk->skb->data;
545 
546         /* Verify the INIT chunk before processing it. */
547         err_chunk = NULL;
548         if (!sctp_verify_init(net, ep, asoc, chunk->chunk_hdr->type,
549                               (struct sctp_init_chunk *)chunk->chunk_hdr, chunk,
550                               &err_chunk)) {
551 
552                 enum sctp_error error = SCTP_ERROR_NO_RESOURCE;
553 
554                 /* This chunk contains fatal error. It is to be discarded.
555                  * Send an ABORT, with causes.  If there are no causes,
556                  * then there wasn't enough memory.  Just terminate
557                  * the association.
558                  */
559                 if (err_chunk) {
560                         packet = sctp_abort_pkt_new(net, ep, asoc, arg,
561                                         (__u8 *)(err_chunk->chunk_hdr) +
562                                         sizeof(struct sctp_chunkhdr),
563                                         ntohs(err_chunk->chunk_hdr->length) -
564                                         sizeof(struct sctp_chunkhdr));
565 
566                         sctp_chunk_free(err_chunk);
567 
568                         if (packet) {
569                                 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
570                                                 SCTP_PACKET(packet));
571                                 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
572                                 error = SCTP_ERROR_INV_PARAM;
573                         }
574                 }
575 
576                 /* SCTP-AUTH, Section 6.3:
577                  *    It should be noted that if the receiver wants to tear
578                  *    down an association in an authenticated way only, the
579                  *    handling of malformed packets should not result in
580                  *    tearing down the association.
581                  *
582                  * This means that if we only want to abort associations
583                  * in an authenticated way (i.e AUTH+ABORT), then we
584                  * can't destroy this association just because the packet
585                  * was malformed.
586                  */
587                 if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc))
588                         return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
589 
590                 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
591                 return sctp_stop_t1_and_abort(net, commands, error, ECONNREFUSED,
592                                                 asoc, chunk->transport);
593         }
594 
595         /* Tag the variable length parameters.  Note that we never
596          * convert the parameters in an INIT chunk.
597          */
598         chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(struct sctp_inithdr));
599 
600         initchunk = (struct sctp_init_chunk *)chunk->chunk_hdr;
601 
602         sctp_add_cmd_sf(commands, SCTP_CMD_PEER_INIT,
603                         SCTP_PEER_INIT(initchunk));
604 
605         /* Reset init error count upon receipt of INIT-ACK.  */
606         sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_RESET, SCTP_NULL());
607 
608         /* 5.1 C) "A" shall stop the T1-init timer and leave
609          * COOKIE-WAIT state.  "A" shall then ... start the T1-cookie
610          * timer, and enter the COOKIE-ECHOED state.
611          */
612         sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
613                         SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
614         sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
615                         SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
616         sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
617                         SCTP_STATE(SCTP_STATE_COOKIE_ECHOED));
618 
619         /* SCTP-AUTH: generate the association shared keys so that
620          * we can potentially sign the COOKIE-ECHO.
621          */
622         sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_SHKEY, SCTP_NULL());
623 
624         /* 5.1 C) "A" shall then send the State Cookie received in the
625          * INIT ACK chunk in a COOKIE ECHO chunk, ...
626          */
627         /* If there is any errors to report, send the ERROR chunk generated
628          * for unknown parameters as well.
629          */
630         sctp_add_cmd_sf(commands, SCTP_CMD_GEN_COOKIE_ECHO,
631                         SCTP_CHUNK(err_chunk));
632 
633         return SCTP_DISPOSITION_CONSUME;
634 }
635 
636 static bool sctp_auth_chunk_verify(struct net *net, struct sctp_chunk *chunk,
637                                    const struct sctp_association *asoc)
638 {
639         struct sctp_chunk auth;
640 
641         if (!chunk->auth_chunk)
642                 return true;
643 
644         /* SCTP-AUTH:  auth_chunk pointer is only set when the cookie-echo
645          * is supposed to be authenticated and we have to do delayed
646          * authentication.  We've just recreated the association using
647          * the information in the cookie and now it's much easier to
648          * do the authentication.
649          */
650 
651         /* Make sure that we and the peer are AUTH capable */
652         if (!net->sctp.auth_enable || !asoc->peer.auth_capable)
653                 return false;
654 
655         /* set-up our fake chunk so that we can process it */
656         auth.skb = chunk->auth_chunk;
657         auth.asoc = chunk->asoc;
658         auth.sctp_hdr = chunk->sctp_hdr;
659         auth.chunk_hdr = (struct sctp_chunkhdr *)
660                                 skb_push(chunk->auth_chunk,
661                                          sizeof(struct sctp_chunkhdr));
662         skb_pull(chunk->auth_chunk, sizeof(struct sctp_chunkhdr));
663         auth.transport = chunk->transport;
664 
665         return sctp_sf_authenticate(asoc, &auth) == SCTP_IERROR_NO_ERROR;
666 }
667 
668 /*
669  * Respond to a normal COOKIE ECHO chunk.
670  * We are the side that is being asked for an association.
671  *
672  * Section: 5.1 Normal Establishment of an Association, D
673  * D) Upon reception of the COOKIE ECHO chunk, Endpoint "Z" will reply
674  *    with a COOKIE ACK chunk after building a TCB and moving to
675  *    the ESTABLISHED state. A COOKIE ACK chunk may be bundled with
676  *    any pending DATA chunks (and/or SACK chunks), but the COOKIE ACK
677  *    chunk MUST be the first chunk in the packet.
678  *
679  *   IMPLEMENTATION NOTE: An implementation may choose to send the
680  *   Communication Up notification to the SCTP user upon reception
681  *   of a valid COOKIE ECHO chunk.
682  *
683  * Verification Tag: 8.5.1 Exceptions in Verification Tag Rules
684  * D) Rules for packet carrying a COOKIE ECHO
685  *
686  * - When sending a COOKIE ECHO, the endpoint MUST use the value of the
687  *   Initial Tag received in the INIT ACK.
688  *
689  * - The receiver of a COOKIE ECHO follows the procedures in Section 5.
690  *
691  * Inputs
692  * (endpoint, asoc, chunk)
693  *
694  * Outputs
695  * (asoc, reply_msg, msg_up, timers, counters)
696  *
697  * The return value is the disposition of the chunk.
698  */
699 enum sctp_disposition sctp_sf_do_5_1D_ce(struct net *net,
700                                          const struct sctp_endpoint *ep,
701                                          const struct sctp_association *asoc,
702                                          const union sctp_subtype type,
703                                          void *arg,
704                                          struct sctp_cmd_seq *commands)
705 {
706         struct sctp_ulpevent *ev, *ai_ev = NULL, *auth_ev = NULL;
707         struct sctp_association *new_asoc;
708         struct sctp_init_chunk *peer_init;
709         struct sctp_chunk *chunk = arg;
710         struct sctp_chunk *err_chk_p;
711         struct sctp_chunk *repl;
712         struct sock *sk;
713         int error = 0;
714 
715         if (asoc && !sctp_vtag_verify(chunk, asoc))
716                 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
717 
718         /* If the packet is an OOTB packet which is temporarily on the
719          * control endpoint, respond with an ABORT.
720          */
721         if (ep == sctp_sk(net->sctp.ctl_sock)->ep) {
722                 SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES);
723                 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands);
724         }
725 
726         /* Make sure that the COOKIE_ECHO chunk has a valid length.
727          * In this case, we check that we have enough for at least a
728          * chunk header.  More detailed verification is done
729          * in sctp_unpack_cookie().
730          */
731         if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr)))
732                 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
733                                                   commands);
734 
735         /* If the endpoint is not listening or if the number of associations
736          * on the TCP-style socket exceed the max backlog, respond with an
737          * ABORT.
738          */
739         sk = ep->base.sk;
740         if (!sctp_sstate(sk, LISTENING) ||
741             (sctp_style(sk, TCP) && sk_acceptq_is_full(sk)))
742                 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands);
743 
744         /* "Decode" the chunk.  We have no optional parameters so we
745          * are in good shape.
746          */
747         chunk->subh.cookie_hdr =
748                 (struct sctp_signed_cookie *)chunk->skb->data;
749         if (!pskb_pull(chunk->skb, ntohs(chunk->chunk_hdr->length) -
750                                          sizeof(struct sctp_chunkhdr)))
751                 goto nomem;
752 
753         /* 5.1 D) Upon reception of the COOKIE ECHO chunk, Endpoint
754          * "Z" will reply with a COOKIE ACK chunk after building a TCB
755          * and moving to the ESTABLISHED state.
756          */
757         new_asoc = sctp_unpack_cookie(ep, asoc, chunk, GFP_ATOMIC, &error,
758                                       &err_chk_p);
759 
760         /* FIXME:
761          * If the re-build failed, what is the proper error path
762          * from here?
763          *
764          * [We should abort the association. --piggy]
765          */
766         if (!new_asoc) {
767                 /* FIXME: Several errors are possible.  A bad cookie should
768                  * be silently discarded, but think about logging it too.
769                  */
770                 switch (error) {
771                 case -SCTP_IERROR_NOMEM:
772                         goto nomem;
773 
774                 case -SCTP_IERROR_STALE_COOKIE:
775                         sctp_send_stale_cookie_err(net, ep, asoc, chunk, commands,
776                                                    err_chk_p);
777                         return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
778 
779                 case -SCTP_IERROR_BAD_SIG:
780                 default:
781                         return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
782                 }
783         }
784 
785         if (security_sctp_assoc_request(new_asoc, chunk->head_skb ?: chunk->skb)) {
786                 sctp_association_free(new_asoc);
787                 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
788         }
789 
790         /* Delay state machine commands until later.
791          *
792          * Re-build the bind address for the association is done in
793          * the sctp_unpack_cookie() already.
794          */
795         /* This is a brand-new association, so these are not yet side
796          * effects--it is safe to run them here.
797          */
798         peer_init = (struct sctp_init_chunk *)(chunk->subh.cookie_hdr + 1);
799         if (!sctp_process_init(new_asoc, chunk,
800                                &chunk->subh.cookie_hdr->c.peer_addr,
801                                peer_init, GFP_ATOMIC))
802                 goto nomem_init;
803 
804         /* SCTP-AUTH:  Now that we've populate required fields in
805          * sctp_process_init, set up the association shared keys as
806          * necessary so that we can potentially authenticate the ACK
807          */
808         error = sctp_auth_asoc_init_active_key(new_asoc, GFP_ATOMIC);
809         if (error)
810                 goto nomem_init;
811 
812         if (!sctp_auth_chunk_verify(net, chunk, new_asoc)) {
813                 sctp_association_free(new_asoc);
814                 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
815         }
816 
817         repl = sctp_make_cookie_ack(new_asoc, chunk);
818         if (!repl)
819                 goto nomem_init;
820 
821         /* RFC 2960 5.1 Normal Establishment of an Association
822          *
823          * D) IMPLEMENTATION NOTE: An implementation may choose to
824          * send the Communication Up notification to the SCTP user
825          * upon reception of a valid COOKIE ECHO chunk.
826          */
827         ev = sctp_ulpevent_make_assoc_change(new_asoc, 0, SCTP_COMM_UP, 0,
828                                              new_asoc->c.sinit_num_ostreams,
829                                              new_asoc->c.sinit_max_instreams,
830                                              NULL, GFP_ATOMIC);
831         if (!ev)
832                 goto nomem_ev;
833 
834         /* Sockets API Draft Section 5.3.1.6
835          * When a peer sends a Adaptation Layer Indication parameter , SCTP
836          * delivers this notification to inform the application that of the
837          * peers requested adaptation layer.
838          */
839         if (new_asoc->peer.adaptation_ind) {
840                 ai_ev = sctp_ulpevent_make_adaptation_indication(new_asoc,
841                                                             GFP_ATOMIC);
842                 if (!ai_ev)
843                         goto nomem_aiev;
844         }
845 
846         if (!new_asoc->peer.auth_capable) {
847                 auth_ev = sctp_ulpevent_make_authkey(new_asoc, 0,
848                                                      SCTP_AUTH_NO_AUTH,
849                                                      GFP_ATOMIC);
850                 if (!auth_ev)
851                         goto nomem_authev;
852         }
853 
854         /* Add all the state machine commands now since we've created
855          * everything.  This way we don't introduce memory corruptions
856          * during side-effect processing and correctly count established
857          * associations.
858          */
859         sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc));
860         sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
861                         SCTP_STATE(SCTP_STATE_ESTABLISHED));
862         SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB);
863         SCTP_INC_STATS(net, SCTP_MIB_PASSIVEESTABS);
864         sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL());
865 
866         if (new_asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE])
867                 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
868                                 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
869 
870         /* This will send the COOKIE ACK */
871         sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
872 
873         /* Queue the ASSOC_CHANGE event */
874         sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));
875 
876         /* Send up the Adaptation Layer Indication event */
877         if (ai_ev)
878                 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
879                                 SCTP_ULPEVENT(ai_ev));
880 
881         if (auth_ev)
882                 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
883                                 SCTP_ULPEVENT(auth_ev));
884 
885         return SCTP_DISPOSITION_CONSUME;
886 
887 nomem_authev:
888         sctp_ulpevent_free(ai_ev);
889 nomem_aiev:
890         sctp_ulpevent_free(ev);
891 nomem_ev:
892         sctp_chunk_free(repl);
893 nomem_init:
894         sctp_association_free(new_asoc);
895 nomem:
896         return SCTP_DISPOSITION_NOMEM;
897 }
898 
899 /*
900  * Respond to a normal COOKIE ACK chunk.
901  * We are the side that is asking for an association.
902  *
903  * RFC 2960 5.1 Normal Establishment of an Association
904  *
905  * E) Upon reception of the COOKIE ACK, endpoint "A" will move from the
906  *    COOKIE-ECHOED state to the ESTABLISHED state, stopping the T1-cookie
907  *    timer. It may also notify its ULP about the successful
908  *    establishment of the association with a Communication Up
909  *    notification (see Section 10).
910  *
911  * Verification Tag:
912  * Inputs
913  * (endpoint, asoc, chunk)
914  *
915  * Outputs
916  * (asoc, reply_msg, msg_up, timers, counters)
917  *
918  * The return value is the disposition of the chunk.
919  */
920 enum sctp_disposition sctp_sf_do_5_1E_ca(struct net *net,
921                                          const struct sctp_endpoint *ep,
922                                          const struct sctp_association *asoc,
923                                          const union sctp_subtype type,
924                                          void *arg,
925                                          struct sctp_cmd_seq *commands)
926 {
927         struct sctp_chunk *chunk = arg;
928         struct sctp_ulpevent *ev;
929 
930         if (!sctp_vtag_verify(chunk, asoc))
931                 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
932 
933         /* Set peer label for connection. */
934         if (security_sctp_assoc_established((struct sctp_association *)asoc,
935                                             chunk->head_skb ?: chunk->skb))
936                 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
937 
938         /* Verify that the chunk length for the COOKIE-ACK is OK.
939          * If we don't do this, any bundled chunks may be junked.
940          */
941         if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr)))
942                 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
943                                                   commands);
944 
945         /* Reset init error count upon receipt of COOKIE-ACK,
946          * to avoid problems with the management of this
947          * counter in stale cookie situations when a transition back
948          * from the COOKIE-ECHOED state to the COOKIE-WAIT
949          * state is performed.
950          */
951         sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_RESET, SCTP_NULL());
952 
953         /* RFC 2960 5.1 Normal Establishment of an Association
954          *
955          * E) Upon reception of the COOKIE ACK, endpoint "A" will move
956          * from the COOKIE-ECHOED state to the ESTABLISHED state,
957          * stopping the T1-cookie timer.
958          */
959         sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
960                         SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
961         sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
962                         SCTP_STATE(SCTP_STATE_ESTABLISHED));
963         SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB);
964         SCTP_INC_STATS(net, SCTP_MIB_ACTIVEESTABS);
965         sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL());
966         if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE])
967                 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
968                                 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
969 
970         /* It may also notify its ULP about the successful
971          * establishment of the association with a Communication Up
972          * notification (see Section 10).
973          */
974         ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_UP,
975                                              0, asoc->c.sinit_num_ostreams,
976                                              asoc->c.sinit_max_instreams,
977                                              NULL, GFP_ATOMIC);
978 
979         if (!ev)
980                 goto nomem;
981 
982         sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));
983 
984         /* Sockets API Draft Section 5.3.1.6
985          * When a peer sends a Adaptation Layer Indication parameter , SCTP
986          * delivers this notification to inform the application that of the
987          * peers requested adaptation layer.
988          */
989         if (asoc->peer.adaptation_ind) {
990                 ev = sctp_ulpevent_make_adaptation_indication(asoc, GFP_ATOMIC);
991                 if (!ev)
992                         goto nomem;
993 
994                 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
995                                 SCTP_ULPEVENT(ev));
996         }
997 
998         if (!asoc->peer.auth_capable) {
999                 ev = sctp_ulpevent_make_authkey(asoc, 0, SCTP_AUTH_NO_AUTH,
1000                                                 GFP_ATOMIC);
1001                 if (!ev)
1002                         goto nomem;
1003                 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
1004                                 SCTP_ULPEVENT(ev));
1005         }
1006 
1007         return SCTP_DISPOSITION_CONSUME;
1008 nomem:
1009         return SCTP_DISPOSITION_NOMEM;
1010 }
1011 
1012 /* Generate and sendout a heartbeat packet.  */
1013 static enum sctp_disposition sctp_sf_heartbeat(
1014                                         const struct sctp_endpoint *ep,
1015                                         const struct sctp_association *asoc,
1016                                         const union sctp_subtype type,
1017                                         void *arg,
1018                                         struct sctp_cmd_seq *commands)
1019 {
1020         struct sctp_transport *transport = (struct sctp_transport *) arg;
1021         struct sctp_chunk *reply;
1022 
1023         /* Send a heartbeat to our peer.  */
1024         reply = sctp_make_heartbeat(asoc, transport, 0);
1025         if (!reply)
1026                 return SCTP_DISPOSITION_NOMEM;
1027 
1028         /* Set rto_pending indicating that an RTT measurement
1029          * is started with this heartbeat chunk.
1030          */
1031         sctp_add_cmd_sf(commands, SCTP_CMD_RTO_PENDING,
1032                         SCTP_TRANSPORT(transport));
1033 
1034         sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
1035         return SCTP_DISPOSITION_CONSUME;
1036 }
1037 
1038 /* Generate a HEARTBEAT packet on the given transport.  */
1039 enum sctp_disposition sctp_sf_sendbeat_8_3(struct net *net,
1040                                            const struct sctp_endpoint *ep,
1041                                            const struct sctp_association *asoc,
1042                                            const union sctp_subtype type,
1043                                            void *arg,
1044                                            struct sctp_cmd_seq *commands)
1045 {
1046         struct sctp_transport *transport = (struct sctp_transport *) arg;
1047 
1048         if (asoc->overall_error_count >= asoc->max_retrans) {
1049                 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
1050                                 SCTP_ERROR(ETIMEDOUT));
1051                 /* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */
1052                 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
1053                                 SCTP_PERR(SCTP_ERROR_NO_ERROR));
1054                 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
1055                 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
1056                 return SCTP_DISPOSITION_DELETE_TCB;
1057         }
1058 
1059         /* Section 3.3.5.
1060          * The Sender-specific Heartbeat Info field should normally include
1061          * information about the sender's current time when this HEARTBEAT
1062          * chunk is sent and the destination transport address to which this
1063          * HEARTBEAT is sent (see Section 8.3).
1064          */
1065 
1066         if (transport->param_flags & SPP_HB_ENABLE) {
1067                 if (SCTP_DISPOSITION_NOMEM ==
1068                                 sctp_sf_heartbeat(ep, asoc, type, arg,
1069                                                   commands))
1070                         return SCTP_DISPOSITION_NOMEM;
1071 
1072                 /* Set transport error counter and association error counter
1073                  * when sending heartbeat.
1074                  */
1075                 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_HB_SENT,
1076                                 SCTP_TRANSPORT(transport));
1077         }
1078         sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_IDLE,
1079                         SCTP_TRANSPORT(transport));
1080         sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMER_UPDATE,
1081                         SCTP_TRANSPORT(transport));
1082 
1083         return SCTP_DISPOSITION_CONSUME;
1084 }
1085 
1086 /* resend asoc strreset_chunk.  */
1087 enum sctp_disposition sctp_sf_send_reconf(struct net *net,
1088                                           const struct sctp_endpoint *ep,
1089                                           const struct sctp_association *asoc,
1090                                           const union sctp_subtype type,
1091                                           void *arg,
1092                                           struct sctp_cmd_seq *commands)
1093 {
1094         struct sctp_transport *transport = arg;
1095 
1096         if (asoc->overall_error_count >= asoc->max_retrans) {
1097                 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
1098                                 SCTP_ERROR(ETIMEDOUT));
1099                 /* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */
1100                 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
1101                                 SCTP_PERR(SCTP_ERROR_NO_ERROR));
1102                 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
1103                 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
1104                 return SCTP_DISPOSITION_DELETE_TCB;
1105         }
1106 
1107         sctp_chunk_hold(asoc->strreset_chunk);
1108         sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1109                         SCTP_CHUNK(asoc->strreset_chunk));
1110         sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, SCTP_TRANSPORT(transport));
1111 
1112         return SCTP_DISPOSITION_CONSUME;
1113 }
1114 
1115 /* send hb chunk with padding for PLPMUTD.  */
1116 enum sctp_disposition sctp_sf_send_probe(struct net *net,
1117                                          const struct sctp_endpoint *ep,
1118                                          const struct sctp_association *asoc,
1119                                          const union sctp_subtype type,
1120                                          void *arg,
1121                                          struct sctp_cmd_seq *commands)
1122 {
1123         struct sctp_transport *transport = (struct sctp_transport *)arg;
1124         struct sctp_chunk *reply;
1125 
1126         if (!sctp_transport_pl_enabled(transport))
1127                 return SCTP_DISPOSITION_CONSUME;
1128 
1129         sctp_transport_pl_send(transport);
1130         reply = sctp_make_heartbeat(asoc, transport, transport->pl.probe_size);
1131         if (!reply)
1132                 return SCTP_DISPOSITION_NOMEM;
1133         sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
1134         sctp_add_cmd_sf(commands, SCTP_CMD_PROBE_TIMER_UPDATE,
1135                         SCTP_TRANSPORT(transport));
1136 
1137         return SCTP_DISPOSITION_CONSUME;
1138 }
1139 
1140 /*
1141  * Process an heartbeat request.
1142  *
1143  * Section: 8.3 Path Heartbeat
1144  * The receiver of the HEARTBEAT should immediately respond with a
1145  * HEARTBEAT ACK that contains the Heartbeat Information field copied
1146  * from the received HEARTBEAT chunk.
1147  *
1148  * Verification Tag:  8.5 Verification Tag [Normal verification]
1149  * When receiving an SCTP packet, the endpoint MUST ensure that the
1150  * value in the Verification Tag field of the received SCTP packet
1151  * matches its own Tag. If the received Verification Tag value does not
1152  * match the receiver's own tag value, the receiver shall silently
1153  * discard the packet and shall not process it any further except for
1154  * those cases listed in Section 8.5.1 below.
1155  *
1156  * Inputs
1157  * (endpoint, asoc, chunk)
1158  *
1159  * Outputs
1160  * (asoc, reply_msg, msg_up, timers, counters)
1161  *
1162  * The return value is the disposition of the chunk.
1163  */
1164 enum sctp_disposition sctp_sf_beat_8_3(struct net *net,
1165                                        const struct sctp_endpoint *ep,
1166                                        const struct sctp_association *asoc,
1167                                        const union sctp_subtype type,
1168                                        void *arg, struct sctp_cmd_seq *commands)
1169 {
1170         struct sctp_paramhdr *param_hdr;
1171         struct sctp_chunk *chunk = arg;
1172         struct sctp_chunk *reply;
1173         size_t paylen = 0;
1174 
1175         if (!sctp_vtag_verify(chunk, asoc))
1176                 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
1177 
1178         /* Make sure that the HEARTBEAT chunk has a valid length. */
1179         if (!sctp_chunk_length_valid(chunk,
1180                                      sizeof(struct sctp_heartbeat_chunk)))
1181                 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
1182                                                   commands);
1183 
1184         /* 8.3 The receiver of the HEARTBEAT should immediately
1185          * respond with a HEARTBEAT ACK that contains the Heartbeat
1186          * Information field copied from the received HEARTBEAT chunk.
1187          */
1188         chunk->subh.hb_hdr = (struct sctp_heartbeathdr *)chunk->skb->data;
1189         param_hdr = (struct sctp_paramhdr *)chunk->subh.hb_hdr;
1190         paylen = ntohs(chunk->chunk_hdr->length) - sizeof(struct sctp_chunkhdr);
1191 
1192         if (ntohs(param_hdr->length) > paylen)
1193                 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg,
1194                                                   param_hdr, commands);
1195 
1196         if (!pskb_pull(chunk->skb, paylen))
1197                 goto nomem;
1198 
1199         reply = sctp_make_heartbeat_ack(asoc, chunk, param_hdr, paylen);
1200         if (!reply)
1201                 goto nomem;
1202 
1203         sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
1204         return SCTP_DISPOSITION_CONSUME;
1205 
1206 nomem:
1207         return SCTP_DISPOSITION_NOMEM;
1208 }
1209 
1210 /*
1211  * Process the returning HEARTBEAT ACK.
1212  *
1213  * Section: 8.3 Path Heartbeat
1214  * Upon the receipt of the HEARTBEAT ACK, the sender of the HEARTBEAT
1215  * should clear the error counter of the destination transport
1216  * address to which the HEARTBEAT was sent, and mark the destination
1217  * transport address as active if it is not so marked. The endpoint may
1218  * optionally report to the upper layer when an inactive destination
1219  * address is marked as active due to the reception of the latest
1220  * HEARTBEAT ACK. The receiver of the HEARTBEAT ACK must also
1221  * clear the association overall error count as well (as defined
1222  * in section 8.1).
1223  *
1224  * The receiver of the HEARTBEAT ACK should also perform an RTT
1225  * measurement for that destination transport address using the time
1226  * value carried in the HEARTBEAT ACK chunk.
1227  *
1228  * Verification Tag:  8.5 Verification Tag [Normal verification]
1229  *
1230  * Inputs
1231  * (endpoint, asoc, chunk)
1232  *
1233  * Outputs
1234  * (asoc, reply_msg, msg_up, timers, counters)
1235  *
1236  * The return value is the disposition of the chunk.
1237  */
1238 enum sctp_disposition sctp_sf_backbeat_8_3(struct net *net,
1239                                            const struct sctp_endpoint *ep,
1240                                            const struct sctp_association *asoc,
1241                                            const union sctp_subtype type,
1242                                            void *arg,
1243                                            struct sctp_cmd_seq *commands)
1244 {
1245         struct sctp_sender_hb_info *hbinfo;
1246         struct sctp_chunk *chunk = arg;
1247         struct sctp_transport *link;
1248         unsigned long max_interval;
1249         union sctp_addr from_addr;
1250 
1251         if (!sctp_vtag_verify(chunk, asoc))
1252                 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
1253 
1254         /* Make sure that the HEARTBEAT-ACK chunk has a valid length.  */
1255         if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr) +
1256                                             sizeof(*hbinfo)))
1257                 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
1258                                                   commands);
1259 
1260         hbinfo = (struct sctp_sender_hb_info *)chunk->skb->data;
1261         /* Make sure that the length of the parameter is what we expect */
1262         if (ntohs(hbinfo->param_hdr.length) != sizeof(*hbinfo))
1263                 return SCTP_DISPOSITION_DISCARD;
1264 
1265         from_addr = hbinfo->daddr;
1266         link = sctp_assoc_lookup_paddr(asoc, &from_addr);
1267 
1268         /* This should never happen, but lets log it if so.  */
1269         if (unlikely(!link)) {
1270                 if (from_addr.sa.sa_family == AF_INET6) {
1271                         net_warn_ratelimited("%s association %p could not find address %pI6\n",
1272                                              __func__,
1273                                              asoc,
1274                                              &from_addr.v6.sin6_addr);
1275                 } else {
1276                         net_warn_ratelimited("%s association %p could not find address %pI4\n",
1277                                              __func__,
1278                                              asoc,
1279                                              &from_addr.v4.sin_addr.s_addr);
1280                 }
1281                 return SCTP_DISPOSITION_DISCARD;
1282         }
1283 
1284         /* Validate the 64-bit random nonce. */
1285         if (hbinfo->hb_nonce != link->hb_nonce)
1286                 return SCTP_DISPOSITION_DISCARD;
1287 
1288         if (hbinfo->probe_size) {
1289                 if (hbinfo->probe_size != link->pl.probe_size ||
1290                     !sctp_transport_pl_enabled(link))
1291                         return SCTP_DISPOSITION_DISCARD;
1292 
1293                 if (sctp_transport_pl_recv(link))
1294                         return SCTP_DISPOSITION_CONSUME;
1295 
1296                 return sctp_sf_send_probe(net, ep, asoc, type, link, commands);
1297         }
1298 
1299         max_interval = link->hbinterval + link->rto;
1300 
1301         /* Check if the timestamp looks valid.  */
1302         if (time_after(hbinfo->sent_at, jiffies) ||
1303             time_after(jiffies, hbinfo->sent_at + max_interval)) {
1304                 pr_debug("%s: HEARTBEAT ACK with invalid timestamp received "
1305                          "for transport:%p\n", __func__, link);
1306 
1307                 return SCTP_DISPOSITION_DISCARD;
1308         }
1309 
1310         /* 8.3 Upon the receipt of the HEARTBEAT ACK, the sender of
1311          * the HEARTBEAT should clear the error counter of the
1312          * destination transport address to which the HEARTBEAT was
1313          * sent and mark the destination transport address as active if
1314          * it is not so marked.
1315          */
1316         sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_ON, SCTP_TRANSPORT(link));
1317 
1318         return SCTP_DISPOSITION_CONSUME;
1319 }
1320 
1321 /* Helper function to send out an abort for the restart
1322  * condition.
1323  */
1324 static int sctp_sf_send_restart_abort(struct net *net, union sctp_addr *ssa,
1325                                       struct sctp_chunk *init,
1326                                       struct sctp_cmd_seq *commands)
1327 {
1328         struct sctp_af *af = sctp_get_af_specific(ssa->v4.sin_family);
1329         union sctp_addr_param *addrparm;
1330         struct sctp_errhdr *errhdr;
1331         char buffer[sizeof(*errhdr) + sizeof(*addrparm)];
1332         struct sctp_endpoint *ep;
1333         struct sctp_packet *pkt;
1334         int len;
1335 
1336         /* Build the error on the stack.   We are way to malloc crazy
1337          * throughout the code today.
1338          */
1339         errhdr = (struct sctp_errhdr *)buffer;
1340         addrparm = (union sctp_addr_param *)(errhdr + 1);
1341 
1342         /* Copy into a parm format. */
1343         len = af->to_addr_param(ssa, addrparm);
1344         len += sizeof(*errhdr);
1345 
1346         errhdr->cause = SCTP_ERROR_RESTART;
1347         errhdr->length = htons(len);
1348 
1349         /* Assign to the control socket. */
1350         ep = sctp_sk(net->sctp.ctl_sock)->ep;
1351 
1352         /* Association is NULL since this may be a restart attack and we
1353          * want to send back the attacker's vtag.
1354          */
1355         pkt = sctp_abort_pkt_new(net, ep, NULL, init, errhdr, len);
1356 
1357         if (!pkt)
1358                 goto out;
1359         sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, SCTP_PACKET(pkt));
1360 
1361         SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
1362 
1363         /* Discard the rest of the inbound packet. */
1364         sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL());
1365 
1366 out:
1367         /* Even if there is no memory, treat as a failure so
1368          * the packet will get dropped.
1369          */
1370         return 0;
1371 }
1372 
1373 static bool list_has_sctp_addr(const struct list_head *list,
1374                                union sctp_addr *ipaddr)
1375 {
1376         struct sctp_transport *addr;
1377 
1378         list_for_each_entry(addr, list, transports) {
1379                 if (sctp_cmp_addr_exact(ipaddr, &addr->ipaddr))
1380                         return true;
1381         }
1382 
1383         return false;
1384 }
1385 /* A restart is occurring, check to make sure no new addresses
1386  * are being added as we may be under a takeover attack.
1387  */
1388 static int sctp_sf_check_restart_addrs(const struct sctp_association *new_asoc,
1389                                        const struct sctp_association *asoc,
1390                                        struct sctp_chunk *init,
1391                                        struct sctp_cmd_seq *commands)
1392 {
1393         struct net *net = new_asoc->base.net;
1394         struct sctp_transport *new_addr;
1395         int ret = 1;
1396 
1397         /* Implementor's Guide - Section 5.2.2
1398          * ...
1399          * Before responding the endpoint MUST check to see if the
1400          * unexpected INIT adds new addresses to the association. If new
1401          * addresses are added to the association, the endpoint MUST respond
1402          * with an ABORT..
1403          */
1404 
1405         /* Search through all current addresses and make sure
1406          * we aren't adding any new ones.
1407          */
1408         list_for_each_entry(new_addr, &new_asoc->peer.transport_addr_list,
1409                             transports) {
1410                 if (!list_has_sctp_addr(&asoc->peer.transport_addr_list,
1411                                         &new_addr->ipaddr)) {
1412                         sctp_sf_send_restart_abort(net, &new_addr->ipaddr, init,
1413                                                    commands);
1414                         ret = 0;
1415                         break;
1416                 }
1417         }
1418 
1419         /* Return success if all addresses were found. */
1420         return ret;
1421 }
1422 
1423 /* Populate the verification/tie tags based on overlapping INIT
1424  * scenario.
1425  *
1426  * Note: Do not use in CLOSED or SHUTDOWN-ACK-SENT state.
1427  */
1428 static void sctp_tietags_populate(struct sctp_association *new_asoc,
1429                                   const struct sctp_association *asoc)
1430 {
1431         switch (asoc->state) {
1432 
1433         /* 5.2.1 INIT received in COOKIE-WAIT or COOKIE-ECHOED State */
1434 
1435         case SCTP_STATE_COOKIE_WAIT:
1436                 new_asoc->c.my_vtag     = asoc->c.my_vtag;
1437                 new_asoc->c.my_ttag     = asoc->c.my_vtag;
1438                 new_asoc->c.peer_ttag   = 0;
1439                 break;
1440 
1441         case SCTP_STATE_COOKIE_ECHOED:
1442                 new_asoc->c.my_vtag     = asoc->c.my_vtag;
1443                 new_asoc->c.my_ttag     = asoc->c.my_vtag;
1444                 new_asoc->c.peer_ttag   = asoc->c.peer_vtag;
1445                 break;
1446 
1447         /* 5.2.2 Unexpected INIT in States Other than CLOSED, COOKIE-ECHOED,
1448          * COOKIE-WAIT and SHUTDOWN-ACK-SENT
1449          */
1450         default:
1451                 new_asoc->c.my_ttag   = asoc->c.my_vtag;
1452                 new_asoc->c.peer_ttag = asoc->c.peer_vtag;
1453                 break;
1454         }
1455 
1456         /* Other parameters for the endpoint SHOULD be copied from the
1457          * existing parameters of the association (e.g. number of
1458          * outbound streams) into the INIT ACK and cookie.
1459          */
1460         new_asoc->rwnd                  = asoc->rwnd;
1461         new_asoc->c.sinit_num_ostreams  = asoc->c.sinit_num_ostreams;
1462         new_asoc->c.sinit_max_instreams = asoc->c.sinit_max_instreams;
1463         new_asoc->c.initial_tsn         = asoc->c.initial_tsn;
1464 }
1465 
1466 /*
1467  * Compare vtag/tietag values to determine unexpected COOKIE-ECHO
1468  * handling action.
1469  *
1470  * RFC 2960 5.2.4 Handle a COOKIE ECHO when a TCB exists.
1471  *
1472  * Returns value representing action to be taken.   These action values
1473  * correspond to Action/Description values in RFC 2960, Table 2.
1474  */
1475 static char sctp_tietags_compare(struct sctp_association *new_asoc,
1476                                  const struct sctp_association *asoc)
1477 {
1478         /* In this case, the peer may have restarted.  */
1479         if ((asoc->c.my_vtag != new_asoc->c.my_vtag) &&
1480             (asoc->c.peer_vtag != new_asoc->c.peer_vtag) &&
1481             (asoc->c.my_vtag == new_asoc->c.my_ttag) &&
1482             (asoc->c.peer_vtag == new_asoc->c.peer_ttag))
1483                 return 'A';
1484 
1485         /* Collision case B. */
1486         if ((asoc->c.my_vtag == new_asoc->c.my_vtag) &&
1487             ((asoc->c.peer_vtag != new_asoc->c.peer_vtag) ||
1488              (0 == asoc->c.peer_vtag))) {
1489                 return 'B';
1490         }
1491 
1492         /* Collision case D. */
1493         if ((asoc->c.my_vtag == new_asoc->c.my_vtag) &&
1494             (asoc->c.peer_vtag == new_asoc->c.peer_vtag))
1495                 return 'D';
1496 
1497         /* Collision case C. */
1498         if ((asoc->c.my_vtag != new_asoc->c.my_vtag) &&
1499             (asoc->c.peer_vtag == new_asoc->c.peer_vtag) &&
1500             (0 == new_asoc->c.my_ttag) &&
1501             (0 == new_asoc->c.peer_ttag))
1502                 return 'C';
1503 
1504         /* No match to any of the special cases; discard this packet. */
1505         return 'E';
1506 }
1507 
1508 /* Common helper routine for both duplicate and simultaneous INIT
1509  * chunk handling.
1510  */
1511 static enum sctp_disposition sctp_sf_do_unexpected_init(
1512                                         struct net *net,
1513                                         const struct sctp_endpoint *ep,
1514                                         const struct sctp_association *asoc,
1515                                         const union sctp_subtype type,
1516                                         void *arg,
1517                                         struct sctp_cmd_seq *commands)
1518 {
1519         struct sctp_chunk *chunk = arg, *repl, *err_chunk;
1520         struct sctp_unrecognized_param *unk_param;
1521         struct sctp_association *new_asoc;
1522         enum sctp_disposition retval;
1523         struct sctp_packet *packet;
1524         int len;
1525 
1526         /* 6.10 Bundling
1527          * An endpoint MUST NOT bundle INIT, INIT ACK or
1528          * SHUTDOWN COMPLETE with any other chunks.
1529          *
1530          * IG Section 2.11.2
1531          * Furthermore, we require that the receiver of an INIT chunk MUST
1532          * enforce these rules by silently discarding an arriving packet
1533          * with an INIT chunk that is bundled with other chunks.
1534          */
1535         if (!chunk->singleton)
1536                 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
1537 
1538         /* Make sure that the INIT chunk has a valid length. */
1539         if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_init_chunk)))
1540                 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
1541 
1542         /* 3.1 A packet containing an INIT chunk MUST have a zero Verification
1543          * Tag.
1544          */
1545         if (chunk->sctp_hdr->vtag != 0)
1546                 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands);
1547 
1548         if (SCTP_INPUT_CB(chunk->skb)->encap_port != chunk->transport->encap_port)
1549                 return sctp_sf_new_encap_port(net, ep, asoc, type, arg, commands);
1550 
1551         /* Grab the INIT header.  */
1552         chunk->subh.init_hdr = (struct sctp_inithdr *)chunk->skb->data;
1553 
1554         /* Tag the variable length parameters.  */
1555         chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(struct sctp_inithdr));
1556 
1557         /* Verify the INIT chunk before processing it. */
1558         err_chunk = NULL;
1559         if (!sctp_verify_init(net, ep, asoc, chunk->chunk_hdr->type,
1560                               (struct sctp_init_chunk *)chunk->chunk_hdr, chunk,
1561                               &err_chunk)) {
1562                 /* This chunk contains fatal error. It is to be discarded.
1563                  * Send an ABORT, with causes if there is any.
1564                  */
1565                 if (err_chunk) {
1566                         packet = sctp_abort_pkt_new(net, ep, asoc, arg,
1567                                         (__u8 *)(err_chunk->chunk_hdr) +
1568                                         sizeof(struct sctp_chunkhdr),
1569                                         ntohs(err_chunk->chunk_hdr->length) -
1570                                         sizeof(struct sctp_chunkhdr));
1571 
1572                         if (packet) {
1573                                 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
1574                                                 SCTP_PACKET(packet));
1575                                 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
1576                                 retval = SCTP_DISPOSITION_CONSUME;
1577                         } else {
1578                                 retval = SCTP_DISPOSITION_NOMEM;
1579                         }
1580                         goto cleanup;
1581                 } else {
1582                         return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg,
1583                                                     commands);
1584                 }
1585         }
1586 
1587         /*
1588          * Other parameters for the endpoint SHOULD be copied from the
1589          * existing parameters of the association (e.g. number of
1590          * outbound streams) into the INIT ACK and cookie.
1591          * FIXME:  We are copying parameters from the endpoint not the
1592          * association.
1593          */
1594         new_asoc = sctp_make_temp_asoc(ep, chunk, GFP_ATOMIC);
1595         if (!new_asoc)
1596                 goto nomem;
1597 
1598         /* Update socket peer label if first association. */
1599         if (security_sctp_assoc_request(new_asoc, chunk->skb)) {
1600                 sctp_association_free(new_asoc);
1601                 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
1602         }
1603 
1604         if (sctp_assoc_set_bind_addr_from_ep(new_asoc,
1605                                 sctp_scope(sctp_source(chunk)), GFP_ATOMIC) < 0)
1606                 goto nomem;
1607 
1608         /* In the outbound INIT ACK the endpoint MUST copy its current
1609          * Verification Tag and Peers Verification tag into a reserved
1610          * place (local tie-tag and per tie-tag) within the state cookie.
1611          */
1612         if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk),
1613                                (struct sctp_init_chunk *)chunk->chunk_hdr,
1614                                GFP_ATOMIC))
1615                 goto nomem;
1616 
1617         /* Make sure no new addresses are being added during the
1618          * restart.   Do not do this check for COOKIE-WAIT state,
1619          * since there are no peer addresses to check against.
1620          * Upon return an ABORT will have been sent if needed.
1621          */
1622         if (!sctp_state(asoc, COOKIE_WAIT)) {
1623                 if (!sctp_sf_check_restart_addrs(new_asoc, asoc, chunk,
1624                                                  commands)) {
1625                         retval = SCTP_DISPOSITION_CONSUME;
1626                         goto nomem_retval;
1627                 }
1628         }
1629 
1630         sctp_tietags_populate(new_asoc, asoc);
1631 
1632         /* B) "Z" shall respond immediately with an INIT ACK chunk.  */
1633 
1634         /* If there are errors need to be reported for unknown parameters,
1635          * make sure to reserve enough room in the INIT ACK for them.
1636          */
1637         len = 0;
1638         if (err_chunk) {
1639                 len = ntohs(err_chunk->chunk_hdr->length) -
1640                       sizeof(struct sctp_chunkhdr);
1641         }
1642 
1643         repl = sctp_make_init_ack(new_asoc, chunk, GFP_ATOMIC, len);
1644         if (!repl)
1645                 goto nomem;
1646 
1647         /* If there are errors need to be reported for unknown parameters,
1648          * include them in the outgoing INIT ACK as "Unrecognized parameter"
1649          * parameter.
1650          */
1651         if (err_chunk) {
1652                 /* Get the "Unrecognized parameter" parameter(s) out of the
1653                  * ERROR chunk generated by sctp_verify_init(). Since the
1654                  * error cause code for "unknown parameter" and the
1655                  * "Unrecognized parameter" type is the same, we can
1656                  * construct the parameters in INIT ACK by copying the
1657                  * ERROR causes over.
1658                  */
1659                 unk_param = (struct sctp_unrecognized_param *)
1660                             ((__u8 *)(err_chunk->chunk_hdr) +
1661                             sizeof(struct sctp_chunkhdr));
1662                 /* Replace the cause code with the "Unrecognized parameter"
1663                  * parameter type.
1664                  */
1665                 sctp_addto_chunk(repl, len, unk_param);
1666         }
1667 
1668         sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc));
1669         sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
1670 
1671         /*
1672          * Note: After sending out INIT ACK with the State Cookie parameter,
1673          * "Z" MUST NOT allocate any resources for this new association.
1674          * Otherwise, "Z" will be vulnerable to resource attacks.
1675          */
1676         sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
1677         retval = SCTP_DISPOSITION_CONSUME;
1678 
1679         return retval;
1680 
1681 nomem:
1682         retval = SCTP_DISPOSITION_NOMEM;
1683 nomem_retval:
1684         if (new_asoc)
1685                 sctp_association_free(new_asoc);
1686 cleanup:
1687         if (err_chunk)
1688                 sctp_chunk_free(err_chunk);
1689         return retval;
1690 }
1691 
1692 /*
1693  * Handle simultaneous INIT.
1694  * This means we started an INIT and then we got an INIT request from
1695  * our peer.
1696  *
1697  * Section: 5.2.1 INIT received in COOKIE-WAIT or COOKIE-ECHOED State (Item B)
1698  * This usually indicates an initialization collision, i.e., each
1699  * endpoint is attempting, at about the same time, to establish an
1700  * association with the other endpoint.
1701  *
1702  * Upon receipt of an INIT in the COOKIE-WAIT or COOKIE-ECHOED state, an
1703  * endpoint MUST respond with an INIT ACK using the same parameters it
1704  * sent in its original INIT chunk (including its Verification Tag,
1705  * unchanged). These original parameters are combined with those from the
1706  * newly received INIT chunk. The endpoint shall also generate a State
1707  * Cookie with the INIT ACK. The endpoint uses the parameters sent in its
1708  * INIT to calculate the State Cookie.
1709  *
1710  * After that, the endpoint MUST NOT change its state, the T1-init
1711  * timer shall be left running and the corresponding TCB MUST NOT be
1712  * destroyed. The normal procedures for handling State Cookies when
1713  * a TCB exists will resolve the duplicate INITs to a single association.
1714  *
1715  * For an endpoint that is in the COOKIE-ECHOED state it MUST populate
1716  * its Tie-Tags with the Tag information of itself and its peer (see
1717  * section 5.2.2 for a description of the Tie-Tags).
1718  *
1719  * Verification Tag: Not explicit, but an INIT can not have a valid
1720  * verification tag, so we skip the check.
1721  *
1722  * Inputs
1723  * (endpoint, asoc, chunk)
1724  *
1725  * Outputs
1726  * (asoc, reply_msg, msg_up, timers, counters)
1727  *
1728  * The return value is the disposition of the chunk.
1729  */
1730 enum sctp_disposition sctp_sf_do_5_2_1_siminit(
1731                                         struct net *net,
1732                                         const struct sctp_endpoint *ep,
1733                                         const struct sctp_association *asoc,
1734                                         const union sctp_subtype type,
1735                                         void *arg,
1736                                         struct sctp_cmd_seq *commands)
1737 {
1738         /* Call helper to do the real work for both simultaneous and
1739          * duplicate INIT chunk handling.
1740          */
1741         return sctp_sf_do_unexpected_init(net, ep, asoc, type, arg, commands);
1742 }
1743 
1744 /*
1745  * Handle duplicated INIT messages.  These are usually delayed
1746  * restransmissions.
1747  *
1748  * Section: 5.2.2 Unexpected INIT in States Other than CLOSED,
1749  * COOKIE-ECHOED and COOKIE-WAIT
1750  *
1751  * Unless otherwise stated, upon reception of an unexpected INIT for
1752  * this association, the endpoint shall generate an INIT ACK with a
1753  * State Cookie.  In the outbound INIT ACK the endpoint MUST copy its
1754  * current Verification Tag and peer's Verification Tag into a reserved
1755  * place within the state cookie.  We shall refer to these locations as
1756  * the Peer's-Tie-Tag and the Local-Tie-Tag.  The outbound SCTP packet
1757  * containing this INIT ACK MUST carry a Verification Tag value equal to
1758  * the Initiation Tag found in the unexpected INIT.  And the INIT ACK
1759  * MUST contain a new Initiation Tag (randomly generated see Section
1760  * 5.3.1).  Other parameters for the endpoint SHOULD be copied from the
1761  * existing parameters of the association (e.g. number of outbound
1762  * streams) into the INIT ACK and cookie.
1763  *
1764  * After sending out the INIT ACK, the endpoint shall take no further
1765  * actions, i.e., the existing association, including its current state,
1766  * and the corresponding TCB MUST NOT be changed.
1767  *
1768  * Note: Only when a TCB exists and the association is not in a COOKIE-
1769  * WAIT state are the Tie-Tags populated.  For a normal association INIT
1770  * (i.e. the endpoint is in a COOKIE-WAIT state), the Tie-Tags MUST be
1771  * set to 0 (indicating that no previous TCB existed).  The INIT ACK and
1772  * State Cookie are populated as specified in section 5.2.1.
1773  *
1774  * Verification Tag: Not specified, but an INIT has no way of knowing
1775  * what the verification tag could be, so we ignore it.
1776  *
1777  * Inputs
1778  * (endpoint, asoc, chunk)
1779  *
1780  * Outputs
1781  * (asoc, reply_msg, msg_up, timers, counters)
1782  *
1783  * The return value is the disposition of the chunk.
1784  */
1785 enum sctp_disposition sctp_sf_do_5_2_2_dupinit(
1786                                         struct net *net,
1787                                         const struct sctp_endpoint *ep,
1788                                         const struct sctp_association *asoc,
1789                                         const union sctp_subtype type,
1790                                         void *arg,
1791                                         struct sctp_cmd_seq *commands)
1792 {
1793         /* Call helper to do the real work for both simultaneous and
1794          * duplicate INIT chunk handling.
1795          */
1796         return sctp_sf_do_unexpected_init(net, ep, asoc, type, arg, commands);
1797 }
1798 
1799 
1800 /*
1801  * Unexpected INIT-ACK handler.
1802  *
1803  * Section 5.2.3
1804  * If an INIT ACK received by an endpoint in any state other than the
1805  * COOKIE-WAIT state, the endpoint should discard the INIT ACK chunk.
1806  * An unexpected INIT ACK usually indicates the processing of an old or
1807  * duplicated INIT chunk.
1808 */
1809 enum sctp_disposition sctp_sf_do_5_2_3_initack(
1810                                         struct net *net,
1811                                         const struct sctp_endpoint *ep,
1812                                         const struct sctp_association *asoc,
1813                                         const union sctp_subtype type,
1814                                         void *arg,
1815                                         struct sctp_cmd_seq *commands)
1816 {
1817         /* Per the above section, we'll discard the chunk if we have an
1818          * endpoint.  If this is an OOTB INIT-ACK, treat it as such.
1819          */
1820         if (ep == sctp_sk(net->sctp.ctl_sock)->ep)
1821                 return sctp_sf_ootb(net, ep, asoc, type, arg, commands);
1822         else
1823                 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands);
1824 }
1825 
1826 static int sctp_sf_do_assoc_update(struct sctp_association *asoc,
1827                                    struct sctp_association *new,
1828                                    struct sctp_cmd_seq *cmds)
1829 {
1830         struct net *net = asoc->base.net;
1831         struct sctp_chunk *abort;
1832 
1833         if (!sctp_assoc_update(asoc, new))
1834                 return 0;
1835 
1836         abort = sctp_make_abort(asoc, NULL, sizeof(struct sctp_errhdr));
1837         if (abort) {
1838                 sctp_init_cause(abort, SCTP_ERROR_RSRC_LOW, 0);
1839                 sctp_add_cmd_sf(cmds, SCTP_CMD_REPLY, SCTP_CHUNK(abort));
1840         }
1841         sctp_add_cmd_sf(cmds, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(ECONNABORTED));
1842         sctp_add_cmd_sf(cmds, SCTP_CMD_ASSOC_FAILED,
1843                         SCTP_PERR(SCTP_ERROR_RSRC_LOW));
1844         SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
1845         SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
1846 
1847         return -ENOMEM;
1848 }
1849 
1850 /* Unexpected COOKIE-ECHO handler for peer restart (Table 2, action 'A')
1851  *
1852  * Section 5.2.4
1853  *  A)  In this case, the peer may have restarted.
1854  */
1855 static enum sctp_disposition sctp_sf_do_dupcook_a(
1856                                         struct net *net,
1857                                         const struct sctp_endpoint *ep,
1858                                         const struct sctp_association *asoc,
1859                                         struct sctp_chunk *chunk,
1860                                         struct sctp_cmd_seq *commands,
1861                                         struct sctp_association *new_asoc)
1862 {
1863         struct sctp_init_chunk *peer_init;
1864         enum sctp_disposition disposition;
1865         struct sctp_ulpevent *ev;
1866         struct sctp_chunk *repl;
1867         struct sctp_chunk *err;
1868 
1869         /* new_asoc is a brand-new association, so these are not yet
1870          * side effects--it is safe to run them here.
1871          */
1872         peer_init = (struct sctp_init_chunk *)(chunk->subh.cookie_hdr + 1);
1873         if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk), peer_init,
1874                                GFP_ATOMIC))
1875                 goto nomem;
1876 
1877         if (sctp_auth_asoc_init_active_key(new_asoc, GFP_ATOMIC))
1878                 goto nomem;
1879 
1880         if (!sctp_auth_chunk_verify(net, chunk, new_asoc))
1881                 return SCTP_DISPOSITION_DISCARD;
1882 
1883         /* Make sure no new addresses are being added during the
1884          * restart.  Though this is a pretty complicated attack
1885          * since you'd have to get inside the cookie.
1886          */
1887         if (!sctp_sf_check_restart_addrs(new_asoc, asoc, chunk, commands))
1888                 return SCTP_DISPOSITION_CONSUME;
1889 
1890         /* If the endpoint is in the SHUTDOWN-ACK-SENT state and recognizes
1891          * the peer has restarted (Action A), it MUST NOT setup a new
1892          * association but instead resend the SHUTDOWN ACK and send an ERROR
1893          * chunk with a "Cookie Received while Shutting Down" error cause to
1894          * its peer.
1895         */
1896         if (sctp_state(asoc, SHUTDOWN_ACK_SENT)) {
1897                 disposition = __sctp_sf_do_9_2_reshutack(net, ep, asoc,
1898                                                          SCTP_ST_CHUNK(chunk->chunk_hdr->type),
1899                                                          chunk, commands);
1900                 if (SCTP_DISPOSITION_NOMEM == disposition)
1901                         goto nomem;
1902 
1903                 err = sctp_make_op_error(asoc, chunk,
1904                                          SCTP_ERROR_COOKIE_IN_SHUTDOWN,
1905                                          NULL, 0, 0);
1906                 if (err)
1907                         sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
1908                                         SCTP_CHUNK(err));
1909 
1910                 return SCTP_DISPOSITION_CONSUME;
1911         }
1912 
1913         /* For now, stop pending T3-rtx and SACK timers, fail any unsent/unacked
1914          * data. Consider the optional choice of resending of this data.
1915          */
1916         sctp_add_cmd_sf(commands, SCTP_CMD_T3_RTX_TIMERS_STOP, SCTP_NULL());
1917         sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
1918                         SCTP_TO(SCTP_EVENT_TIMEOUT_SACK));
1919         sctp_add_cmd_sf(commands, SCTP_CMD_PURGE_OUTQUEUE, SCTP_NULL());
1920 
1921         /* Stop pending T4-rto timer, teardown ASCONF queue, ASCONF-ACK queue
1922          * and ASCONF-ACK cache.
1923          */
1924         sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
1925                         SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
1926         sctp_add_cmd_sf(commands, SCTP_CMD_PURGE_ASCONF_QUEUE, SCTP_NULL());
1927 
1928         /* Update the content of current association. */
1929         if (sctp_sf_do_assoc_update((struct sctp_association *)asoc, new_asoc, commands))
1930                 goto nomem;
1931 
1932         repl = sctp_make_cookie_ack(asoc, chunk);
1933         if (!repl)
1934                 goto nomem;
1935 
1936         /* Report association restart to upper layer. */
1937         ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_RESTART, 0,
1938                                              asoc->c.sinit_num_ostreams,
1939                                              asoc->c.sinit_max_instreams,
1940                                              NULL, GFP_ATOMIC);
1941         if (!ev)
1942                 goto nomem_ev;
1943 
1944         sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));
1945         if ((sctp_state(asoc, SHUTDOWN_PENDING) ||
1946              sctp_state(asoc, SHUTDOWN_SENT)) &&
1947             (sctp_sstate(asoc->base.sk, CLOSING) ||
1948              sock_flag(asoc->base.sk, SOCK_DEAD))) {
1949                 /* If the socket has been closed by user, don't
1950                  * transition to ESTABLISHED. Instead trigger SHUTDOWN
1951                  * bundled with COOKIE_ACK.
1952                  */
1953                 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
1954                 return sctp_sf_do_9_2_start_shutdown(net, ep, asoc,
1955                                                      SCTP_ST_CHUNK(0), repl,
1956                                                      commands);
1957         } else {
1958                 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
1959                                 SCTP_STATE(SCTP_STATE_ESTABLISHED));
1960                 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
1961         }
1962         return SCTP_DISPOSITION_CONSUME;
1963 
1964 nomem_ev:
1965         sctp_chunk_free(repl);
1966 nomem:
1967         return SCTP_DISPOSITION_NOMEM;
1968 }
1969 
1970 /* Unexpected COOKIE-ECHO handler for setup collision (Table 2, action 'B')
1971  *
1972  * Section 5.2.4
1973  *   B) In this case, both sides may be attempting to start an association
1974  *      at about the same time but the peer endpoint started its INIT
1975  *      after responding to the local endpoint's INIT
1976  */
1977 /* This case represents an initialization collision.  */
1978 static enum sctp_disposition sctp_sf_do_dupcook_b(
1979                                         struct net *net,
1980                                         const struct sctp_endpoint *ep,
1981                                         const struct sctp_association *asoc,
1982                                         struct sctp_chunk *chunk,
1983                                         struct sctp_cmd_seq *commands,
1984                                         struct sctp_association *new_asoc)
1985 {
1986         struct sctp_init_chunk *peer_init;
1987         struct sctp_chunk *repl;
1988 
1989         /* new_asoc is a brand-new association, so these are not yet
1990          * side effects--it is safe to run them here.
1991          */
1992         peer_init = (struct sctp_init_chunk *)(chunk->subh.cookie_hdr + 1);
1993         if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk), peer_init,
1994                                GFP_ATOMIC))
1995                 goto nomem;
1996 
1997         if (sctp_auth_asoc_init_active_key(new_asoc, GFP_ATOMIC))
1998                 goto nomem;
1999 
2000         if (!sctp_auth_chunk_verify(net, chunk, new_asoc))
2001                 return SCTP_DISPOSITION_DISCARD;
2002 
2003         sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
2004                         SCTP_STATE(SCTP_STATE_ESTABLISHED));
2005         if (asoc->state < SCTP_STATE_ESTABLISHED)
2006                 SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB);
2007         sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL());
2008 
2009         /* Update the content of current association.  */
2010         if (sctp_sf_do_assoc_update((struct sctp_association *)asoc, new_asoc, commands))
2011                 goto nomem;
2012 
2013         repl = sctp_make_cookie_ack(asoc, chunk);
2014         if (!repl)
2015                 goto nomem;
2016 
2017         sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
2018 
2019         /* RFC 2960 5.1 Normal Establishment of an Association
2020          *
2021          * D) IMPLEMENTATION NOTE: An implementation may choose to
2022          * send the Communication Up notification to the SCTP user
2023          * upon reception of a valid COOKIE ECHO chunk.
2024          *
2025          * Sadly, this needs to be implemented as a side-effect, because
2026          * we are not guaranteed to have set the association id of the real
2027          * association and so these notifications need to be delayed until
2028          * the association id is allocated.
2029          */
2030 
2031         sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_CHANGE, SCTP_U8(SCTP_COMM_UP));
2032 
2033         /* Sockets API Draft Section 5.3.1.6
2034          * When a peer sends a Adaptation Layer Indication parameter , SCTP
2035          * delivers this notification to inform the application that of the
2036          * peers requested adaptation layer.
2037          *
2038          * This also needs to be done as a side effect for the same reason as
2039          * above.
2040          */
2041         if (asoc->peer.adaptation_ind)
2042                 sctp_add_cmd_sf(commands, SCTP_CMD_ADAPTATION_IND, SCTP_NULL());
2043 
2044         if (!asoc->peer.auth_capable)
2045                 sctp_add_cmd_sf(commands, SCTP_CMD_PEER_NO_AUTH, SCTP_NULL());
2046 
2047         return SCTP_DISPOSITION_CONSUME;
2048 
2049 nomem:
2050         return SCTP_DISPOSITION_NOMEM;
2051 }
2052 
2053 /* Unexpected COOKIE-ECHO handler for setup collision (Table 2, action 'C')
2054  *
2055  * Section 5.2.4
2056  *  C) In this case, the local endpoint's cookie has arrived late.
2057  *     Before it arrived, the local endpoint sent an INIT and received an
2058  *     INIT-ACK and finally sent a COOKIE ECHO with the peer's same tag
2059  *     but a new tag of its own.
2060  */
2061 /* This case represents an initialization collision.  */
2062 static enum sctp_disposition sctp_sf_do_dupcook_c(
2063                                         struct net *net,
2064                                         const struct sctp_endpoint *ep,
2065                                         const struct sctp_association *asoc,
2066                                         struct sctp_chunk *chunk,
2067                                         struct sctp_cmd_seq *commands,
2068                                         struct sctp_association *new_asoc)
2069 {
2070         /* The cookie should be silently discarded.
2071          * The endpoint SHOULD NOT change states and should leave
2072          * any timers running.
2073          */
2074         return SCTP_DISPOSITION_DISCARD;
2075 }
2076 
2077 /* Unexpected COOKIE-ECHO handler lost chunk (Table 2, action 'D')
2078  *
2079  * Section 5.2.4
2080  *
2081  * D) When both local and remote tags match the endpoint should always
2082  *    enter the ESTABLISHED state, if it has not already done so.
2083  */
2084 /* This case represents an initialization collision.  */
2085 static enum sctp_disposition sctp_sf_do_dupcook_d(
2086                                         struct net *net,
2087                                         const struct sctp_endpoint *ep,
2088                                         const struct sctp_association *asoc,
2089                                         struct sctp_chunk *chunk,
2090                                         struct sctp_cmd_seq *commands,
2091                                         struct sctp_association *new_asoc)
2092 {
2093         struct sctp_ulpevent *ev = NULL, *ai_ev = NULL, *auth_ev = NULL;
2094         struct sctp_chunk *repl;
2095 
2096         /* Clarification from Implementor's Guide:
2097          * D) When both local and remote tags match the endpoint should
2098          * enter the ESTABLISHED state, if it is in the COOKIE-ECHOED state.
2099          * It should stop any cookie timer that may be running and send
2100          * a COOKIE ACK.
2101          */
2102 
2103         if (!sctp_auth_chunk_verify(net, chunk, asoc))
2104                 return SCTP_DISPOSITION_DISCARD;
2105 
2106         /* Don't accidentally move back into established state. */
2107         if (asoc->state < SCTP_STATE_ESTABLISHED) {
2108                 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
2109                                 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
2110                 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
2111                                 SCTP_STATE(SCTP_STATE_ESTABLISHED));
2112                 SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB);
2113                 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START,
2114                                 SCTP_NULL());
2115 
2116                 /* RFC 2960 5.1 Normal Establishment of an Association
2117                  *
2118                  * D) IMPLEMENTATION NOTE: An implementation may choose
2119                  * to send the Communication Up notification to the
2120                  * SCTP user upon reception of a valid COOKIE
2121                  * ECHO chunk.
2122                  */
2123                 ev = sctp_ulpevent_make_assoc_change(asoc, 0,
2124                                              SCTP_COMM_UP, 0,
2125                                              asoc->c.sinit_num_ostreams,
2126                                              asoc->c.sinit_max_instreams,
2127                                              NULL, GFP_ATOMIC);
2128                 if (!ev)
2129                         goto nomem;
2130 
2131                 /* Sockets API Draft Section 5.3.1.6
2132                  * When a peer sends a Adaptation Layer Indication parameter,
2133                  * SCTP delivers this notification to inform the application
2134                  * that of the peers requested adaptation layer.
2135                  */
2136                 if (asoc->peer.adaptation_ind) {
2137                         ai_ev = sctp_ulpevent_make_adaptation_indication(asoc,
2138                                                                  GFP_ATOMIC);
2139                         if (!ai_ev)
2140                                 goto nomem;
2141 
2142                 }
2143 
2144                 if (!asoc->peer.auth_capable) {
2145                         auth_ev = sctp_ulpevent_make_authkey(asoc, 0,
2146                                                              SCTP_AUTH_NO_AUTH,
2147                                                              GFP_ATOMIC);
2148                         if (!auth_ev)
2149                                 goto nomem;
2150                 }
2151         }
2152 
2153         repl = sctp_make_cookie_ack(asoc, chunk);
2154         if (!repl)
2155                 goto nomem;
2156 
2157         sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
2158 
2159         if (ev)
2160                 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
2161                                 SCTP_ULPEVENT(ev));
2162         if (ai_ev)
2163                 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
2164                                         SCTP_ULPEVENT(ai_ev));
2165         if (auth_ev)
2166                 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
2167                                 SCTP_ULPEVENT(auth_ev));
2168 
2169         return SCTP_DISPOSITION_CONSUME;
2170 
2171 nomem:
2172         if (auth_ev)
2173                 sctp_ulpevent_free(auth_ev);
2174         if (ai_ev)
2175                 sctp_ulpevent_free(ai_ev);
2176         if (ev)
2177                 sctp_ulpevent_free(ev);
2178         return SCTP_DISPOSITION_NOMEM;
2179 }
2180 
2181 /*
2182  * Handle a duplicate COOKIE-ECHO.  This usually means a cookie-carrying
2183  * chunk was retransmitted and then delayed in the network.
2184  *
2185  * Section: 5.2.4 Handle a COOKIE ECHO when a TCB exists
2186  *
2187  * Verification Tag: None.  Do cookie validation.
2188  *
2189  * Inputs
2190  * (endpoint, asoc, chunk)
2191  *
2192  * Outputs
2193  * (asoc, reply_msg, msg_up, timers, counters)
2194  *
2195  * The return value is the disposition of the chunk.
2196  */
2197 enum sctp_disposition sctp_sf_do_5_2_4_dupcook(
2198                                         struct net *net,
2199                                         const struct sctp_endpoint *ep,
2200                                         const struct sctp_association *asoc,
2201                                         const union sctp_subtype type,
2202                                         void *arg,
2203                                         struct sctp_cmd_seq *commands)
2204 {
2205         struct sctp_association *new_asoc;
2206         struct sctp_chunk *chunk = arg;
2207         enum sctp_disposition retval;
2208         struct sctp_chunk *err_chk_p;
2209         int error = 0;
2210         char action;
2211 
2212         /* Make sure that the chunk has a valid length from the protocol
2213          * perspective.  In this case check to make sure we have at least
2214          * enough for the chunk header.  Cookie length verification is
2215          * done later.
2216          */
2217         if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) {
2218                 if (!sctp_vtag_verify(chunk, asoc))
2219                         asoc = NULL;
2220                 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, commands);
2221         }
2222 
2223         /* "Decode" the chunk.  We have no optional parameters so we
2224          * are in good shape.
2225          */
2226         chunk->subh.cookie_hdr = (struct sctp_signed_cookie *)chunk->skb->data;
2227         if (!pskb_pull(chunk->skb, ntohs(chunk->chunk_hdr->length) -
2228                                         sizeof(struct sctp_chunkhdr)))
2229                 goto nomem;
2230 
2231         /* In RFC 2960 5.2.4 3, if both Verification Tags in the State Cookie
2232          * of a duplicate COOKIE ECHO match the Verification Tags of the
2233          * current association, consider the State Cookie valid even if
2234          * the lifespan is exceeded.
2235          */
2236         new_asoc = sctp_unpack_cookie(ep, asoc, chunk, GFP_ATOMIC, &error,
2237                                       &err_chk_p);
2238 
2239         /* FIXME:
2240          * If the re-build failed, what is the proper error path
2241          * from here?
2242          *
2243          * [We should abort the association. --piggy]
2244          */
2245         if (!new_asoc) {
2246                 /* FIXME: Several errors are possible.  A bad cookie should
2247                  * be silently discarded, but think about logging it too.
2248                  */
2249                 switch (error) {
2250                 case -SCTP_IERROR_NOMEM:
2251                         goto nomem;
2252 
2253                 case -SCTP_IERROR_STALE_COOKIE:
2254                         sctp_send_stale_cookie_err(net, ep, asoc, chunk, commands,
2255                                                    err_chk_p);
2256                         return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2257                 case -SCTP_IERROR_BAD_SIG:
2258                 default:
2259                         return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2260                 }
2261         }
2262 
2263         /* Set temp so that it won't be added into hashtable */
2264         new_asoc->temp = 1;
2265 
2266         /* Compare the tie_tag in cookie with the verification tag of
2267          * current association.
2268          */
2269         action = sctp_tietags_compare(new_asoc, asoc);
2270 
2271         /* In cases C and E the association doesn't enter the ESTABLISHED
2272          * state, so there is no need to call security_sctp_assoc_request().
2273          */
2274         switch (action) {
2275         case 'A': /* Association restart. */
2276         case 'B': /* Collision case B. */
2277         case 'D': /* Collision case D. */
2278                 /* Update socket peer label if first association. */
2279                 if (security_sctp_assoc_request((struct sctp_association *)asoc,
2280                                                 chunk->head_skb ?: chunk->skb)) {
2281                         sctp_association_free(new_asoc);
2282                         return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2283                 }
2284                 break;
2285         }
2286 
2287         switch (action) {
2288         case 'A': /* Association restart. */
2289                 retval = sctp_sf_do_dupcook_a(net, ep, asoc, chunk, commands,
2290                                               new_asoc);
2291                 break;
2292 
2293         case 'B': /* Collision case B. */
2294                 retval = sctp_sf_do_dupcook_b(net, ep, asoc, chunk, commands,
2295                                               new_asoc);
2296                 break;
2297 
2298         case 'C': /* Collision case C. */
2299                 retval = sctp_sf_do_dupcook_c(net, ep, asoc, chunk, commands,
2300                                               new_asoc);
2301                 break;
2302 
2303         case 'D': /* Collision case D. */
2304                 retval = sctp_sf_do_dupcook_d(net, ep, asoc, chunk, commands,
2305                                               new_asoc);
2306                 break;
2307 
2308         default: /* Discard packet for all others. */
2309                 retval = sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2310                 break;
2311         }
2312 
2313         /* Delete the temporary new association. */
2314         sctp_add_cmd_sf(commands, SCTP_CMD_SET_ASOC, SCTP_ASOC(new_asoc));
2315         sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
2316 
2317         /* Restore association pointer to provide SCTP command interpreter
2318          * with a valid context in case it needs to manipulate
2319          * the queues */
2320         sctp_add_cmd_sf(commands, SCTP_CMD_SET_ASOC,
2321                          SCTP_ASOC((struct sctp_association *)asoc));
2322 
2323         return retval;
2324 
2325 nomem:
2326         return SCTP_DISPOSITION_NOMEM;
2327 }
2328 
2329 /*
2330  * Process an ABORT.  (SHUTDOWN-PENDING state)
2331  *
2332  * See sctp_sf_do_9_1_abort().
2333  */
2334 enum sctp_disposition sctp_sf_shutdown_pending_abort(
2335                                         struct net *net,
2336                                         const struct sctp_endpoint *ep,
2337                                         const struct sctp_association *asoc,
2338                                         const union sctp_subtype type,
2339                                         void *arg,
2340                                         struct sctp_cmd_seq *commands)
2341 {
2342         struct sctp_chunk *chunk = arg;
2343 
2344         if (!sctp_vtag_verify_either(chunk, asoc))
2345                 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2346 
2347         /* Make sure that the ABORT chunk has a valid length.
2348          * Since this is an ABORT chunk, we have to discard it
2349          * because of the following text:
2350          * RFC 2960, Section 3.3.7
2351          *    If an endpoint receives an ABORT with a format error or for an
2352          *    association that doesn't exist, it MUST silently discard it.
2353          * Because the length is "invalid", we can't really discard just
2354          * as we do not know its true length.  So, to be safe, discard the
2355          * packet.
2356          */
2357         if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_abort_chunk)))
2358                 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2359 
2360         /* ADD-IP: Special case for ABORT chunks
2361          * F4)  One special consideration is that ABORT Chunks arriving
2362          * destined to the IP address being deleted MUST be
2363          * ignored (see Section 5.3.1 for further details).
2364          */
2365         if (SCTP_ADDR_DEL ==
2366                     sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest))
2367                 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2368 
2369         if (!sctp_err_chunk_valid(chunk))
2370                 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2371 
2372         return __sctp_sf_do_9_1_abort(net, ep, asoc, type, arg, commands);
2373 }
2374 
2375 /*
2376  * Process an ABORT.  (SHUTDOWN-SENT state)
2377  *
2378  * See sctp_sf_do_9_1_abort().
2379  */
2380 enum sctp_disposition sctp_sf_shutdown_sent_abort(
2381                                         struct net *net,
2382                                         const struct sctp_endpoint *ep,
2383                                         const struct sctp_association *asoc,
2384                                         const union sctp_subtype type,
2385                                         void *arg,
2386                                         struct sctp_cmd_seq *commands)
2387 {
2388         struct sctp_chunk *chunk = arg;
2389 
2390         if (!sctp_vtag_verify_either(chunk, asoc))
2391                 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2392 
2393         /* Make sure that the ABORT chunk has a valid length.
2394          * Since this is an ABORT chunk, we have to discard it
2395          * because of the following text:
2396          * RFC 2960, Section 3.3.7
2397          *    If an endpoint receives an ABORT with a format error or for an
2398          *    association that doesn't exist, it MUST silently discard it.
2399          * Because the length is "invalid", we can't really discard just
2400          * as we do not know its true length.  So, to be safe, discard the
2401          * packet.
2402          */
2403         if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_abort_chunk)))
2404                 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2405 
2406         /* ADD-IP: Special case for ABORT chunks
2407          * F4)  One special consideration is that ABORT Chunks arriving
2408          * destined to the IP address being deleted MUST be
2409          * ignored (see Section 5.3.1 for further details).
2410          */
2411         if (SCTP_ADDR_DEL ==
2412                     sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest))
2413                 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2414 
2415         if (!sctp_err_chunk_valid(chunk))
2416                 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2417 
2418         /* Stop the T2-shutdown timer. */
2419         sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
2420                         SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
2421 
2422         /* Stop the T5-shutdown guard timer.  */
2423         sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
2424                         SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
2425 
2426         return __sctp_sf_do_9_1_abort(net, ep, asoc, type, arg, commands);
2427 }
2428 
2429 /*
2430  * Process an ABORT.  (SHUTDOWN-ACK-SENT state)
2431  *
2432  * See sctp_sf_do_9_1_abort().
2433  */
2434 enum sctp_disposition sctp_sf_shutdown_ack_sent_abort(
2435                                         struct net *net,
2436                                         const struct sctp_endpoint *ep,
2437                                         const struct sctp_association *asoc,
2438                                         const union sctp_subtype type,
2439                                         void *arg,
2440                                         struct sctp_cmd_seq *commands)
2441 {
2442         /* The same T2 timer, so we should be able to use
2443          * common function with the SHUTDOWN-SENT state.
2444          */
2445         return sctp_sf_shutdown_sent_abort(net, ep, asoc, type, arg, commands);
2446 }
2447 
2448 /*
2449  * Handle an Error received in COOKIE_ECHOED state.
2450  *
2451  * Only handle the error type of stale COOKIE Error, the other errors will
2452  * be ignored.
2453  *
2454  * Inputs
2455  * (endpoint, asoc, chunk)
2456  *
2457  * Outputs
2458  * (asoc, reply_msg, msg_up, timers, counters)
2459  *
2460  * The return value is the disposition of the chunk.
2461  */
2462 enum sctp_disposition sctp_sf_cookie_echoed_err(
2463                                         struct net *net,
2464                                         const struct sctp_endpoint *ep,
2465                                         const struct sctp_association *asoc,
2466                                         const union sctp_subtype type,
2467                                         void *arg,
2468                                         struct sctp_cmd_seq *commands)
2469 {
2470         struct sctp_chunk *chunk = arg;
2471         struct sctp_errhdr *err;
2472 
2473         if (!sctp_vtag_verify(chunk, asoc))
2474                 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2475 
2476         /* Make sure that the ERROR chunk has a valid length.
2477          * The parameter walking depends on this as well.
2478          */
2479         if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_operr_chunk)))
2480                 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
2481                                                   commands);
2482 
2483         /* Process the error here */
2484         /* FUTURE FIXME:  When PR-SCTP related and other optional
2485          * parms are emitted, this will have to change to handle multiple
2486          * errors.
2487          */
2488         sctp_walk_errors(err, chunk->chunk_hdr) {
2489                 if (SCTP_ERROR_STALE_COOKIE == err->cause)
2490                         return sctp_sf_do_5_2_6_stale(net, ep, asoc, type,
2491                                                         arg, commands);
2492         }
2493 
2494         /* It is possible to have malformed error causes, and that
2495          * will cause us to end the walk early.  However, since
2496          * we are discarding the packet, there should be no adverse
2497          * affects.
2498          */
2499         return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2500 }
2501 
2502 /*
2503  * Handle a Stale COOKIE Error
2504  *
2505  * Section: 5.2.6 Handle Stale COOKIE Error
2506  * If the association is in the COOKIE-ECHOED state, the endpoint may elect
2507  * one of the following three alternatives.
2508  * ...
2509  * 3) Send a new INIT chunk to the endpoint, adding a Cookie
2510  *    Preservative parameter requesting an extension to the lifetime of
2511  *    the State Cookie. When calculating the time extension, an
2512  *    implementation SHOULD use the RTT information measured based on the
2513  *    previous COOKIE ECHO / ERROR exchange, and should add no more
2514  *    than 1 second beyond the measured RTT, due to long State Cookie
2515  *    lifetimes making the endpoint more subject to a replay attack.
2516  *
2517  * Verification Tag:  Not explicit, but safe to ignore.
2518  *
2519  * Inputs
2520  * (endpoint, asoc, chunk)
2521  *
2522  * Outputs
2523  * (asoc, reply_msg, msg_up, timers, counters)
2524  *
2525  * The return value is the disposition of the chunk.
2526  */
2527 static enum sctp_disposition sctp_sf_do_5_2_6_stale(
2528                                         struct net *net,
2529                                         const struct sctp_endpoint *ep,
2530                                         const struct sctp_association *asoc,
2531                                         const union sctp_subtype type,
2532                                         void *arg,
2533                                         struct sctp_cmd_seq *commands)
2534 {
2535         int attempts = asoc->init_err_counter + 1;
2536         struct sctp_chunk *chunk = arg, *reply;
2537         struct sctp_cookie_preserve_param bht;
2538         struct sctp_bind_addr *bp;
2539         struct sctp_errhdr *err;
2540         u32 stale;
2541 
2542         if (attempts > asoc->max_init_attempts) {
2543                 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
2544                                 SCTP_ERROR(ETIMEDOUT));
2545                 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
2546                                 SCTP_PERR(SCTP_ERROR_STALE_COOKIE));
2547                 return SCTP_DISPOSITION_DELETE_TCB;
2548         }
2549 
2550         err = (struct sctp_errhdr *)(chunk->skb->data);
2551 
2552         /* When calculating the time extension, an implementation
2553          * SHOULD use the RTT information measured based on the
2554          * previous COOKIE ECHO / ERROR exchange, and should add no
2555          * more than 1 second beyond the measured RTT, due to long
2556          * State Cookie lifetimes making the endpoint more subject to
2557          * a replay attack.
2558          * Measure of Staleness's unit is usec. (1/1000000 sec)
2559          * Suggested Cookie Life-span Increment's unit is msec.
2560          * (1/1000 sec)
2561          * In general, if you use the suggested cookie life, the value
2562          * found in the field of measure of staleness should be doubled
2563          * to give ample time to retransmit the new cookie and thus
2564          * yield a higher probability of success on the reattempt.
2565          */
2566         stale = ntohl(*(__be32 *)((u8 *)err + sizeof(*err)));
2567         stale = (stale * 2) / 1000;
2568 
2569         bht.param_hdr.type = SCTP_PARAM_COOKIE_PRESERVATIVE;
2570         bht.param_hdr.length = htons(sizeof(bht));
2571         bht.lifespan_increment = htonl(stale);
2572 
2573         /* Build that new INIT chunk.  */
2574         bp = (struct sctp_bind_addr *) &asoc->base.bind_addr;
2575         reply = sctp_make_init(asoc, bp, GFP_ATOMIC, sizeof(bht));
2576         if (!reply)
2577                 goto nomem;
2578 
2579         sctp_addto_chunk(reply, sizeof(bht), &bht);
2580 
2581         /* Clear peer's init_tag cached in assoc as we are sending a new INIT */
2582         sctp_add_cmd_sf(commands, SCTP_CMD_CLEAR_INIT_TAG, SCTP_NULL());
2583 
2584         /* Stop pending T3-rtx and heartbeat timers */
2585         sctp_add_cmd_sf(commands, SCTP_CMD_T3_RTX_TIMERS_STOP, SCTP_NULL());
2586         sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL());
2587 
2588         /* Delete non-primary peer ip addresses since we are transitioning
2589          * back to the COOKIE-WAIT state
2590          */
2591         sctp_add_cmd_sf(commands, SCTP_CMD_DEL_NON_PRIMARY, SCTP_NULL());
2592 
2593         /* If we've sent any data bundled with COOKIE-ECHO we will need to
2594          * resend
2595          */
2596         sctp_add_cmd_sf(commands, SCTP_CMD_T1_RETRAN,
2597                         SCTP_TRANSPORT(asoc->peer.primary_path));
2598 
2599         /* Cast away the const modifier, as we want to just
2600          * rerun it through as a sideffect.
2601          */
2602         sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_INC, SCTP_NULL());
2603 
2604         sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
2605                         SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
2606         sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
2607                         SCTP_STATE(SCTP_STATE_COOKIE_WAIT));
2608         sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
2609                         SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
2610 
2611         sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
2612 
2613         return SCTP_DISPOSITION_CONSUME;
2614 
2615 nomem:
2616         return SCTP_DISPOSITION_NOMEM;
2617 }
2618 
2619 /*
2620  * Process an ABORT.
2621  *
2622  * Section: 9.1
2623  * After checking the Verification Tag, the receiving endpoint shall
2624  * remove the association from its record, and shall report the
2625  * termination to its upper layer.
2626  *
2627  * Verification Tag: 8.5.1 Exceptions in Verification Tag Rules
2628  * B) Rules for packet carrying ABORT:
2629  *
2630  *  - The endpoint shall always fill in the Verification Tag field of the
2631  *    outbound packet with the destination endpoint's tag value if it
2632  *    is known.
2633  *
2634  *  - If the ABORT is sent in response to an OOTB packet, the endpoint
2635  *    MUST follow the procedure described in Section 8.4.
2636  *
2637  *  - The receiver MUST accept the packet if the Verification Tag
2638  *    matches either its own tag, OR the tag of its peer. Otherwise, the
2639  *    receiver MUST silently discard the packet and take no further
2640  *    action.
2641  *
2642  * Inputs
2643  * (endpoint, asoc, chunk)
2644  *
2645  * Outputs
2646  * (asoc, reply_msg, msg_up, timers, counters)
2647  *
2648  * The return value is the disposition of the chunk.
2649  */
2650 enum sctp_disposition sctp_sf_do_9_1_abort(
2651                                         struct net *net,
2652                                         const struct sctp_endpoint *ep,
2653                                         const struct sctp_association *asoc,
2654                                         const union sctp_subtype type,
2655                                         void *arg,
2656                                         struct sctp_cmd_seq *commands)
2657 {
2658         struct sctp_chunk *chunk = arg;
2659 
2660         if (!sctp_vtag_verify_either(chunk, asoc))
2661                 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2662 
2663         /* Make sure that the ABORT chunk has a valid length.
2664          * Since this is an ABORT chunk, we have to discard it
2665          * because of the following text:
2666          * RFC 2960, Section 3.3.7
2667          *    If an endpoint receives an ABORT with a format error or for an
2668          *    association that doesn't exist, it MUST silently discard it.
2669          * Because the length is "invalid", we can't really discard just
2670          * as we do not know its true length.  So, to be safe, discard the
2671          * packet.
2672          */
2673         if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_abort_chunk)))
2674                 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2675 
2676         /* ADD-IP: Special case for ABORT chunks
2677          * F4)  One special consideration is that ABORT Chunks arriving
2678          * destined to the IP address being deleted MUST be
2679          * ignored (see Section 5.3.1 for further details).
2680          */
2681         if (SCTP_ADDR_DEL ==
2682                     sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest))
2683                 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2684 
2685         if (!sctp_err_chunk_valid(chunk))
2686                 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2687 
2688         return __sctp_sf_do_9_1_abort(net, ep, asoc, type, arg, commands);
2689 }
2690 
2691 static enum sctp_disposition __sctp_sf_do_9_1_abort(
2692                                         struct net *net,
2693                                         const struct sctp_endpoint *ep,
2694                                         const struct sctp_association *asoc,
2695                                         const union sctp_subtype type,
2696                                         void *arg,
2697                                         struct sctp_cmd_seq *commands)
2698 {
2699         __be16 error = SCTP_ERROR_NO_ERROR;
2700         struct sctp_chunk *chunk = arg;
2701         unsigned int len;
2702 
2703         /* See if we have an error cause code in the chunk.  */
2704         len = ntohs(chunk->chunk_hdr->length);
2705         if (len >= sizeof(struct sctp_chunkhdr) + sizeof(struct sctp_errhdr))
2706                 error = ((struct sctp_errhdr *)chunk->skb->data)->cause;
2707 
2708         sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(ECONNRESET));
2709         /* ASSOC_FAILED will DELETE_TCB. */
2710         sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, SCTP_PERR(error));
2711         SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
2712         SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
2713 
2714         return SCTP_DISPOSITION_ABORT;
2715 }
2716 
2717 /*
2718  * Process an ABORT.  (COOKIE-WAIT state)
2719  *
2720  * See sctp_sf_do_9_1_abort() above.
2721  */
2722 enum sctp_disposition sctp_sf_cookie_wait_abort(
2723                                         struct net *net,
2724                                         const struct sctp_endpoint *ep,
2725                                         const struct sctp_association *asoc,
2726                                         const union sctp_subtype type,
2727                                         void *arg,
2728                                         struct sctp_cmd_seq *commands)
2729 {
2730         __be16 error = SCTP_ERROR_NO_ERROR;
2731         struct sctp_chunk *chunk = arg;
2732         unsigned int len;
2733 
2734         if (!sctp_vtag_verify_either(chunk, asoc))
2735                 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2736 
2737         /* Make sure that the ABORT chunk has a valid length.
2738          * Since this is an ABORT chunk, we have to discard it
2739          * because of the following text:
2740          * RFC 2960, Section 3.3.7
2741          *    If an endpoint receives an ABORT with a format error or for an
2742          *    association that doesn't exist, it MUST silently discard it.
2743          * Because the length is "invalid", we can't really discard just
2744          * as we do not know its true length.  So, to be safe, discard the
2745          * packet.
2746          */
2747         if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_abort_chunk)))
2748                 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2749 
2750         /* See if we have an error cause code in the chunk.  */
2751         len = ntohs(chunk->chunk_hdr->length);
2752         if (len >= sizeof(struct sctp_chunkhdr) + sizeof(struct sctp_errhdr))
2753                 error = ((struct sctp_errhdr *)chunk->skb->data)->cause;
2754 
2755         return sctp_stop_t1_and_abort(net, commands, error, ECONNREFUSED, asoc,
2756                                       chunk->transport);
2757 }
2758 
2759 /*
2760  * Process an incoming ICMP as an ABORT.  (COOKIE-WAIT state)
2761  */
2762 enum sctp_disposition sctp_sf_cookie_wait_icmp_abort(
2763                                         struct net *net,
2764                                         const struct sctp_endpoint *ep,
2765                                         const struct sctp_association *asoc,
2766                                         const union sctp_subtype type,
2767                                         void *arg,
2768                                         struct sctp_cmd_seq *commands)
2769 {
2770         return sctp_stop_t1_and_abort(net, commands, SCTP_ERROR_NO_ERROR,
2771                                       ENOPROTOOPT, asoc,
2772                                       (struct sctp_transport *)arg);
2773 }
2774 
2775 /*
2776  * Process an ABORT.  (COOKIE-ECHOED state)
2777  */
2778 enum sctp_disposition sctp_sf_cookie_echoed_abort(
2779                                         struct net *net,
2780                                         const struct sctp_endpoint *ep,
2781                                         const struct sctp_association *asoc,
2782                                         const union sctp_subtype type,
2783                                         void *arg,
2784                                         struct sctp_cmd_seq *commands)
2785 {
2786         /* There is a single T1 timer, so we should be able to use
2787          * common function with the COOKIE-WAIT state.
2788          */
2789         return sctp_sf_cookie_wait_abort(net, ep, asoc, type, arg, commands);
2790 }
2791 
2792 /*
2793  * Stop T1 timer and abort association with "INIT failed".
2794  *
2795  * This is common code called by several sctp_sf_*_abort() functions above.
2796  */
2797 static enum sctp_disposition sctp_stop_t1_and_abort(
2798                                         struct net *net,
2799                                         struct sctp_cmd_seq *commands,
2800                                         __be16 error, int sk_err,
2801                                         const struct sctp_association *asoc,
2802                                         struct sctp_transport *transport)
2803 {
2804         pr_debug("%s: ABORT received (INIT)\n", __func__);
2805 
2806         sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
2807                         SCTP_STATE(SCTP_STATE_CLOSED));
2808         SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
2809         sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
2810                         SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
2811         sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(sk_err));
2812         /* CMD_INIT_FAILED will DELETE_TCB. */
2813         sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
2814                         SCTP_PERR(error));
2815 
2816         return SCTP_DISPOSITION_ABORT;
2817 }
2818 
2819 /*
2820  * sctp_sf_do_9_2_shut
2821  *
2822  * Section: 9.2
2823  * Upon the reception of the SHUTDOWN, the peer endpoint shall
2824  *  - enter the SHUTDOWN-RECEIVED state,
2825  *
2826  *  - stop accepting new data from its SCTP user
2827  *
2828  *  - verify, by checking the Cumulative TSN Ack field of the chunk,
2829  *    that all its outstanding DATA chunks have been received by the
2830  *    SHUTDOWN sender.
2831  *
2832  * Once an endpoint as reached the SHUTDOWN-RECEIVED state it MUST NOT
2833  * send a SHUTDOWN in response to a ULP request. And should discard
2834  * subsequent SHUTDOWN chunks.
2835  *
2836  * If there are still outstanding DATA chunks left, the SHUTDOWN
2837  * receiver shall continue to follow normal data transmission
2838  * procedures defined in Section 6 until all outstanding DATA chunks
2839  * are acknowledged; however, the SHUTDOWN receiver MUST NOT accept
2840  * new data from its SCTP user.
2841  *
2842  * Verification Tag:  8.5 Verification Tag [Normal verification]
2843  *
2844  * Inputs
2845  * (endpoint, asoc, chunk)
2846  *
2847  * Outputs
2848  * (asoc, reply_msg, msg_up, timers, counters)
2849  *
2850  * The return value is the disposition of the chunk.
2851  */
2852 enum sctp_disposition sctp_sf_do_9_2_shutdown(
2853                                         struct net *net,
2854                                         const struct sctp_endpoint *ep,
2855                                         const struct sctp_association *asoc,
2856                                         const union sctp_subtype type,
2857                                         void *arg,
2858                                         struct sctp_cmd_seq *commands)
2859 {
2860         enum sctp_disposition disposition;
2861         struct sctp_chunk *chunk = arg;
2862         struct sctp_shutdownhdr *sdh;
2863         struct sctp_ulpevent *ev;
2864         __u32 ctsn;
2865 
2866         if (!sctp_vtag_verify(chunk, asoc))
2867                 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2868 
2869         /* Make sure that the SHUTDOWN chunk has a valid length. */
2870         if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_shutdown_chunk)))
2871                 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
2872                                                   commands);
2873 
2874         /* Convert the elaborate header.  */
2875         sdh = (struct sctp_shutdownhdr *)chunk->skb->data;
2876         skb_pull(chunk->skb, sizeof(*sdh));
2877         chunk->subh.shutdown_hdr = sdh;
2878         ctsn = ntohl(sdh->cum_tsn_ack);
2879 
2880         if (TSN_lt(ctsn, asoc->ctsn_ack_point)) {
2881                 pr_debug("%s: ctsn:%x, ctsn_ack_point:%x\n", __func__, ctsn,
2882                          asoc->ctsn_ack_point);
2883 
2884                 return SCTP_DISPOSITION_DISCARD;
2885         }
2886 
2887         /* If Cumulative TSN Ack beyond the max tsn currently
2888          * send, terminating the association and respond to the
2889          * sender with an ABORT.
2890          */
2891         if (!TSN_lt(ctsn, asoc->next_tsn))
2892                 return sctp_sf_violation_ctsn(net, ep, asoc, type, arg, commands);
2893 
2894         /* API 5.3.1.5 SCTP_SHUTDOWN_EVENT
2895          * When a peer sends a SHUTDOWN, SCTP delivers this notification to
2896          * inform the application that it should cease sending data.
2897          */
2898         ev = sctp_ulpevent_make_shutdown_event(asoc, 0, GFP_ATOMIC);
2899         if (!ev) {
2900                 disposition = SCTP_DISPOSITION_NOMEM;
2901                 goto out;
2902         }
2903         sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));
2904 
2905         /* Upon the reception of the SHUTDOWN, the peer endpoint shall
2906          *  - enter the SHUTDOWN-RECEIVED state,
2907          *  - stop accepting new data from its SCTP user
2908          *
2909          * [This is implicit in the new state.]
2910          */
2911         sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
2912                         SCTP_STATE(SCTP_STATE_SHUTDOWN_RECEIVED));
2913         disposition = SCTP_DISPOSITION_CONSUME;
2914 
2915         if (sctp_outq_is_empty(&asoc->outqueue)) {
2916                 disposition = sctp_sf_do_9_2_shutdown_ack(net, ep, asoc, type,
2917                                                           arg, commands);
2918         }
2919 
2920         if (SCTP_DISPOSITION_NOMEM == disposition)
2921                 goto out;
2922 
2923         /*  - verify, by checking the Cumulative TSN Ack field of the
2924          *    chunk, that all its outstanding DATA chunks have been
2925          *    received by the SHUTDOWN sender.
2926          */
2927         sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_CTSN,
2928                         SCTP_BE32(chunk->subh.shutdown_hdr->cum_tsn_ack));
2929 
2930 out:
2931         return disposition;
2932 }
2933 
2934 /*
2935  * sctp_sf_do_9_2_shut_ctsn
2936  *
2937  * Once an endpoint has reached the SHUTDOWN-RECEIVED state,
2938  * it MUST NOT send a SHUTDOWN in response to a ULP request.
2939  * The Cumulative TSN Ack of the received SHUTDOWN chunk
2940  * MUST be processed.
2941  */
2942 enum sctp_disposition sctp_sf_do_9_2_shut_ctsn(
2943                                         struct net *net,
2944                                         const struct sctp_endpoint *ep,
2945                                         const struct sctp_association *asoc,
2946                                         const union sctp_subtype type,
2947                                         void *arg,
2948                                         struct sctp_cmd_seq *commands)
2949 {
2950         struct sctp_chunk *chunk = arg;
2951         struct sctp_shutdownhdr *sdh;
2952         __u32 ctsn;
2953 
2954         if (!sctp_vtag_verify(chunk, asoc))
2955                 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
2956 
2957         /* Make sure that the SHUTDOWN chunk has a valid length. */
2958         if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_shutdown_chunk)))
2959                 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
2960                                                   commands);
2961 
2962         sdh = (struct sctp_shutdownhdr *)chunk->skb->data;
2963         ctsn = ntohl(sdh->cum_tsn_ack);
2964 
2965         if (TSN_lt(ctsn, asoc->ctsn_ack_point)) {
2966                 pr_debug("%s: ctsn:%x, ctsn_ack_point:%x\n", __func__, ctsn,
2967                          asoc->ctsn_ack_point);
2968 
2969                 return SCTP_DISPOSITION_DISCARD;
2970         }
2971 
2972         /* If Cumulative TSN Ack beyond the max tsn currently
2973          * send, terminating the association and respond to the
2974          * sender with an ABORT.
2975          */
2976         if (!TSN_lt(ctsn, asoc->next_tsn))
2977                 return sctp_sf_violation_ctsn(net, ep, asoc, type, arg, commands);
2978 
2979         /* verify, by checking the Cumulative TSN Ack field of the
2980          * chunk, that all its outstanding DATA chunks have been
2981          * received by the SHUTDOWN sender.
2982          */
2983         sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_CTSN,
2984                         SCTP_BE32(sdh->cum_tsn_ack));
2985 
2986         return SCTP_DISPOSITION_CONSUME;
2987 }
2988 
2989 /* RFC 2960 9.2
2990  * If an endpoint is in SHUTDOWN-ACK-SENT state and receives an INIT chunk
2991  * (e.g., if the SHUTDOWN COMPLETE was lost) with source and destination
2992  * transport addresses (either in the IP addresses or in the INIT chunk)
2993  * that belong to this association, it should discard the INIT chunk and
2994  * retransmit the SHUTDOWN ACK chunk.
2995  */
2996 static enum sctp_disposition
2997 __sctp_sf_do_9_2_reshutack(struct net *net, const struct sctp_endpoint *ep,
2998                            const struct sctp_association *asoc,
2999                            const union sctp_subtype type, void *arg,
3000                            struct sctp_cmd_seq *commands)
3001 {
3002         struct sctp_chunk *chunk = arg;
3003         struct sctp_chunk *reply;
3004 
3005         /* Make sure that the chunk has a valid length */
3006         if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr)))
3007                 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3008                                                   commands);
3009 
3010         /* Since we are not going to really process this INIT, there
3011          * is no point in verifying chunk boundaries.  Just generate
3012          * the SHUTDOWN ACK.
3013          */
3014         reply = sctp_make_shutdown_ack(asoc, chunk);
3015         if (NULL == reply)
3016                 goto nomem;
3017 
3018         /* Set the transport for the SHUTDOWN ACK chunk and the timeout for
3019          * the T2-SHUTDOWN timer.
3020          */
3021         sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply));
3022 
3023         /* and restart the T2-shutdown timer. */
3024         sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
3025                         SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
3026 
3027         sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
3028 
3029         return SCTP_DISPOSITION_CONSUME;
3030 nomem:
3031         return SCTP_DISPOSITION_NOMEM;
3032 }
3033 
3034 enum sctp_disposition
3035 sctp_sf_do_9_2_reshutack(struct net *net, const struct sctp_endpoint *ep,
3036                          const struct sctp_association *asoc,
3037                          const union sctp_subtype type, void *arg,
3038                          struct sctp_cmd_seq *commands)
3039 {
3040         struct sctp_chunk *chunk = arg;
3041 
3042         if (!chunk->singleton)
3043                 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3044 
3045         if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_init_chunk)))
3046                 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3047 
3048         if (chunk->sctp_hdr->vtag != 0)
3049                 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands);
3050 
3051         return __sctp_sf_do_9_2_reshutack(net, ep, asoc, type, arg, commands);
3052 }
3053 
3054 /*
3055  * sctp_sf_do_ecn_cwr
3056  *
3057  * Section:  Appendix A: Explicit Congestion Notification
3058  *
3059  * CWR:
3060  *
3061  * RFC 2481 details a specific bit for a sender to send in the header of
3062  * its next outbound TCP segment to indicate to its peer that it has
3063  * reduced its congestion window.  This is termed the CWR bit.  For
3064  * SCTP the same indication is made by including the CWR chunk.
3065  * This chunk contains one data element, i.e. the TSN number that
3066  * was sent in the ECNE chunk.  This element represents the lowest
3067  * TSN number in the datagram that was originally marked with the
3068  * CE bit.
3069  *
3070  * Verification Tag: 8.5 Verification Tag [Normal verification]
3071  * Inputs
3072  * (endpoint, asoc, chunk)
3073  *
3074  * Outputs
3075  * (asoc, reply_msg, msg_up, timers, counters)
3076  *
3077  * The return value is the disposition of the chunk.
3078  */
3079 enum sctp_disposition sctp_sf_do_ecn_cwr(struct net *net,
3080                                          const struct sctp_endpoint *ep,
3081                                          const struct sctp_association *asoc,
3082                                          const union sctp_subtype type,
3083                                          void *arg,
3084                                          struct sctp_cmd_seq *commands)
3085 {
3086         struct sctp_chunk *chunk = arg;
3087         struct sctp_cwrhdr *cwr;
3088         u32 lowest_tsn;
3089 
3090         if (!sctp_vtag_verify(chunk, asoc))
3091                 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3092 
3093         if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_ecne_chunk)))
3094                 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3095                                                   commands);
3096 
3097         cwr = (struct sctp_cwrhdr *)chunk->skb->data;
3098         skb_pull(chunk->skb, sizeof(*cwr));
3099 
3100         lowest_tsn = ntohl(cwr->lowest_tsn);
3101 
3102         /* Does this CWR ack the last sent congestion notification? */
3103         if (TSN_lte(asoc->last_ecne_tsn, lowest_tsn)) {
3104                 /* Stop sending ECNE. */
3105                 sctp_add_cmd_sf(commands,
3106                                 SCTP_CMD_ECN_CWR,
3107                                 SCTP_U32(lowest_tsn));
3108         }
3109         return SCTP_DISPOSITION_CONSUME;
3110 }
3111 
3112 /*
3113  * sctp_sf_do_ecne
3114  *
3115  * Section:  Appendix A: Explicit Congestion Notification
3116  *
3117  * ECN-Echo
3118  *
3119  * RFC 2481 details a specific bit for a receiver to send back in its
3120  * TCP acknowledgements to notify the sender of the Congestion
3121  * Experienced (CE) bit having arrived from the network.  For SCTP this
3122  * same indication is made by including the ECNE chunk.  This chunk
3123  * contains one data element, i.e. the lowest TSN associated with the IP
3124  * datagram marked with the CE bit.....
3125  *
3126  * Verification Tag: 8.5 Verification Tag [Normal verification]
3127  * Inputs
3128  * (endpoint, asoc, chunk)
3129  *
3130  * Outputs
3131  * (asoc, reply_msg, msg_up, timers, counters)
3132  *
3133  * The return value is the disposition of the chunk.
3134  */
3135 enum sctp_disposition sctp_sf_do_ecne(struct net *net,
3136                                       const struct sctp_endpoint *ep,
3137                                       const struct sctp_association *asoc,
3138                                       const union sctp_subtype type,
3139                                       void *arg, struct sctp_cmd_seq *commands)
3140 {
3141         struct sctp_chunk *chunk = arg;
3142         struct sctp_ecnehdr *ecne;
3143 
3144         if (!sctp_vtag_verify(chunk, asoc))
3145                 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3146 
3147         if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_ecne_chunk)))
3148                 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3149                                                   commands);
3150 
3151         ecne = (struct sctp_ecnehdr *)chunk->skb->data;
3152         skb_pull(chunk->skb, sizeof(*ecne));
3153 
3154         /* If this is a newer ECNE than the last CWR packet we sent out */
3155         sctp_add_cmd_sf(commands, SCTP_CMD_ECN_ECNE,
3156                         SCTP_U32(ntohl(ecne->lowest_tsn)));
3157 
3158         return SCTP_DISPOSITION_CONSUME;
3159 }
3160 
3161 /*
3162  * Section: 6.2  Acknowledgement on Reception of DATA Chunks
3163  *
3164  * The SCTP endpoint MUST always acknowledge the reception of each valid
3165  * DATA chunk.
3166  *
3167  * The guidelines on delayed acknowledgement algorithm specified in
3168  * Section 4.2 of [RFC2581] SHOULD be followed. Specifically, an
3169  * acknowledgement SHOULD be generated for at least every second packet
3170  * (not every second DATA chunk) received, and SHOULD be generated within
3171  * 200 ms of the arrival of any unacknowledged DATA chunk. In some
3172  * situations it may be beneficial for an SCTP transmitter to be more
3173  * conservative than the algorithms detailed in this document allow.
3174  * However, an SCTP transmitter MUST NOT be more aggressive than the
3175  * following algorithms allow.
3176  *
3177  * A SCTP receiver MUST NOT generate more than one SACK for every
3178  * incoming packet, other than to update the offered window as the
3179  * receiving application consumes new data.
3180  *
3181  * Verification Tag:  8.5 Verification Tag [Normal verification]
3182  *
3183  * Inputs
3184  * (endpoint, asoc, chunk)
3185  *
3186  * Outputs
3187  * (asoc, reply_msg, msg_up, timers, counters)
3188  *
3189  * The return value is the disposition of the chunk.
3190  */
3191 enum sctp_disposition sctp_sf_eat_data_6_2(struct net *net,
3192                                            const struct sctp_endpoint *ep,
3193                                            const struct sctp_association *asoc,
3194                                            const union sctp_subtype type,
3195                                            void *arg,
3196                                            struct sctp_cmd_seq *commands)
3197 {
3198         union sctp_arg force = SCTP_NOFORCE();
3199         struct sctp_chunk *chunk = arg;
3200         int error;
3201 
3202         if (!sctp_vtag_verify(chunk, asoc)) {
3203                 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
3204                                 SCTP_NULL());
3205                 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3206         }
3207 
3208         if (!sctp_chunk_length_valid(chunk, sctp_datachk_len(&asoc->stream)))
3209                 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3210                                                   commands);
3211 
3212         error = sctp_eat_data(asoc, chunk, commands);
3213         switch (error) {
3214         case SCTP_IERROR_NO_ERROR:
3215                 break;
3216         case SCTP_IERROR_HIGH_TSN:
3217         case SCTP_IERROR_BAD_STREAM:
3218                 SCTP_INC_STATS(net, SCTP_MIB_IN_DATA_CHUNK_DISCARDS);
3219                 goto discard_noforce;
3220         case SCTP_IERROR_DUP_TSN:
3221         case SCTP_IERROR_IGNORE_TSN:
3222                 SCTP_INC_STATS(net, SCTP_MIB_IN_DATA_CHUNK_DISCARDS);
3223                 goto discard_force;
3224         case SCTP_IERROR_NO_DATA:
3225                 return SCTP_DISPOSITION_ABORT;
3226         case SCTP_IERROR_PROTO_VIOLATION:
3227                 return sctp_sf_abort_violation(net, ep, asoc, chunk, commands,
3228                                                (u8 *)chunk->subh.data_hdr,
3229                                                sctp_datahdr_len(&asoc->stream));
3230         default:
3231                 BUG();
3232         }
3233 
3234         if (chunk->chunk_hdr->flags & SCTP_DATA_SACK_IMM)
3235                 force = SCTP_FORCE();
3236 
3237         if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) {
3238                 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
3239                                 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
3240         }
3241 
3242         /* If this is the last chunk in a packet, we need to count it
3243          * toward sack generation.  Note that we need to SACK every
3244          * OTHER packet containing data chunks, EVEN IF WE DISCARD
3245          * THEM.  We elect to NOT generate SACK's if the chunk fails
3246          * the verification tag test.
3247          *
3248          * RFC 2960 6.2 Acknowledgement on Reception of DATA Chunks
3249          *
3250          * The SCTP endpoint MUST always acknowledge the reception of
3251          * each valid DATA chunk.
3252          *
3253          * The guidelines on delayed acknowledgement algorithm
3254          * specified in  Section 4.2 of [RFC2581] SHOULD be followed.
3255          * Specifically, an acknowledgement SHOULD be generated for at
3256          * least every second packet (not every second DATA chunk)
3257          * received, and SHOULD be generated within 200 ms of the
3258          * arrival of any unacknowledged DATA chunk.  In some
3259          * situations it may be beneficial for an SCTP transmitter to
3260          * be more conservative than the algorithms detailed in this
3261          * document allow. However, an SCTP transmitter MUST NOT be
3262          * more aggressive than the following algorithms allow.
3263          */
3264         if (chunk->end_of_packet)
3265                 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, force);
3266 
3267         return SCTP_DISPOSITION_CONSUME;
3268 
3269 discard_force:
3270         /* RFC 2960 6.2 Acknowledgement on Reception of DATA Chunks
3271          *
3272          * When a packet arrives with duplicate DATA chunk(s) and with
3273          * no new DATA chunk(s), the endpoint MUST immediately send a
3274          * SACK with no delay.  If a packet arrives with duplicate
3275          * DATA chunk(s) bundled with new DATA chunks, the endpoint
3276          * MAY immediately send a SACK.  Normally receipt of duplicate
3277          * DATA chunks will occur when the original SACK chunk was lost
3278          * and the peer's RTO has expired.  The duplicate TSN number(s)
3279          * SHOULD be reported in the SACK as duplicate.
3280          */
3281         /* In our case, we split the MAY SACK advice up whether or not
3282          * the last chunk is a duplicate.'
3283          */
3284         if (chunk->end_of_packet)
3285                 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE());
3286         return SCTP_DISPOSITION_DISCARD;
3287 
3288 discard_noforce:
3289         if (chunk->end_of_packet)
3290                 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, force);
3291 
3292         return SCTP_DISPOSITION_DISCARD;
3293 }
3294 
3295 /*
3296  * sctp_sf_eat_data_fast_4_4
3297  *
3298  * Section: 4 (4)
3299  * (4) In SHUTDOWN-SENT state the endpoint MUST acknowledge any received
3300  *    DATA chunks without delay.
3301  *
3302  * Verification Tag:  8.5 Verification Tag [Normal verification]
3303  * Inputs
3304  * (endpoint, asoc, chunk)
3305  *
3306  * Outputs
3307  * (asoc, reply_msg, msg_up, timers, counters)
3308  *
3309  * The return value is the disposition of the chunk.
3310  */
3311 enum sctp_disposition sctp_sf_eat_data_fast_4_4(
3312                                         struct net *net,
3313                                         const struct sctp_endpoint *ep,
3314                                         const struct sctp_association *asoc,
3315                                         const union sctp_subtype type,
3316                                         void *arg,
3317                                         struct sctp_cmd_seq *commands)
3318 {
3319         struct sctp_chunk *chunk = arg;
3320         int error;
3321 
3322         if (!sctp_vtag_verify(chunk, asoc)) {
3323                 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
3324                                 SCTP_NULL());
3325                 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3326         }
3327 
3328         if (!sctp_chunk_length_valid(chunk, sctp_datachk_len(&asoc->stream)))
3329                 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3330                                                   commands);
3331 
3332         error = sctp_eat_data(asoc, chunk, commands);
3333         switch (error) {
3334         case SCTP_IERROR_NO_ERROR:
3335         case SCTP_IERROR_HIGH_TSN:
3336         case SCTP_IERROR_DUP_TSN:
3337         case SCTP_IERROR_IGNORE_TSN:
3338         case SCTP_IERROR_BAD_STREAM:
3339                 break;
3340         case SCTP_IERROR_NO_DATA:
3341                 return SCTP_DISPOSITION_ABORT;
3342         case SCTP_IERROR_PROTO_VIOLATION:
3343                 return sctp_sf_abort_violation(net, ep, asoc, chunk, commands,
3344                                                (u8 *)chunk->subh.data_hdr,
3345                                                sctp_datahdr_len(&asoc->stream));
3346         default:
3347                 BUG();
3348         }
3349 
3350         /* Go a head and force a SACK, since we are shutting down. */
3351 
3352         /* Implementor's Guide.
3353          *
3354          * While in SHUTDOWN-SENT state, the SHUTDOWN sender MUST immediately
3355          * respond to each received packet containing one or more DATA chunk(s)
3356          * with a SACK, a SHUTDOWN chunk, and restart the T2-shutdown timer
3357          */
3358         if (chunk->end_of_packet) {
3359                 /* We must delay the chunk creation since the cumulative
3360                  * TSN has not been updated yet.
3361                  */
3362                 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SHUTDOWN, SCTP_NULL());
3363                 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE());
3364                 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
3365                                 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
3366         }
3367 
3368         return SCTP_DISPOSITION_CONSUME;
3369 }
3370 
3371 /*
3372  * Section: 6.2  Processing a Received SACK
3373  * D) Any time a SACK arrives, the endpoint performs the following:
3374  *
3375  *     i) If Cumulative TSN Ack is less than the Cumulative TSN Ack Point,
3376  *     then drop the SACK.   Since Cumulative TSN Ack is monotonically
3377  *     increasing, a SACK whose Cumulative TSN Ack is less than the
3378  *     Cumulative TSN Ack Point indicates an out-of-order SACK.
3379  *
3380  *     ii) Set rwnd equal to the newly received a_rwnd minus the number
3381  *     of bytes still outstanding after processing the Cumulative TSN Ack
3382  *     and the Gap Ack Blocks.
3383  *
3384  *     iii) If the SACK is missing a TSN that was previously
3385  *     acknowledged via a Gap Ack Block (e.g., the data receiver
3386  *     reneged on the data), then mark the corresponding DATA chunk
3387  *     as available for retransmit:  Mark it as missing for fast
3388  *     retransmit as described in Section 7.2.4 and if no retransmit
3389  *     timer is running for the destination address to which the DATA
3390  *     chunk was originally transmitted, then T3-rtx is started for
3391  *     that destination address.
3392  *
3393  * Verification Tag:  8.5 Verification Tag [Normal verification]
3394  *
3395  * Inputs
3396  * (endpoint, asoc, chunk)
3397  *
3398  * Outputs
3399  * (asoc, reply_msg, msg_up, timers, counters)
3400  *
3401  * The return value is the disposition of the chunk.
3402  */
3403 enum sctp_disposition sctp_sf_eat_sack_6_2(struct net *net,
3404                                            const struct sctp_endpoint *ep,
3405                                            const struct sctp_association *asoc,
3406                                            const union sctp_subtype type,
3407                                            void *arg,
3408                                            struct sctp_cmd_seq *commands)
3409 {
3410         struct sctp_chunk *chunk = arg;
3411         struct sctp_sackhdr *sackh;
3412         __u32 ctsn;
3413 
3414         if (!sctp_vtag_verify(chunk, asoc))
3415                 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3416 
3417         /* Make sure that the SACK chunk has a valid length. */
3418         if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_sack_chunk)))
3419                 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3420                                                   commands);
3421 
3422         /* Pull the SACK chunk from the data buffer */
3423         sackh = sctp_sm_pull_sack(chunk);
3424         /* Was this a bogus SACK? */
3425         if (!sackh)
3426                 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3427         chunk->subh.sack_hdr = sackh;
3428         ctsn = ntohl(sackh->cum_tsn_ack);
3429 
3430         /* If Cumulative TSN Ack beyond the max tsn currently
3431          * send, terminating the association and respond to the
3432          * sender with an ABORT.
3433          */
3434         if (TSN_lte(asoc->next_tsn, ctsn))
3435                 return sctp_sf_violation_ctsn(net, ep, asoc, type, arg, commands);
3436 
3437         trace_sctp_probe(ep, asoc, chunk);
3438 
3439         /* i) If Cumulative TSN Ack is less than the Cumulative TSN
3440          *     Ack Point, then drop the SACK.  Since Cumulative TSN
3441          *     Ack is monotonically increasing, a SACK whose
3442          *     Cumulative TSN Ack is less than the Cumulative TSN Ack
3443          *     Point indicates an out-of-order SACK.
3444          */
3445         if (TSN_lt(ctsn, asoc->ctsn_ack_point)) {
3446                 pr_debug("%s: ctsn:%x, ctsn_ack_point:%x\n", __func__, ctsn,
3447                          asoc->ctsn_ack_point);
3448 
3449                 return SCTP_DISPOSITION_DISCARD;
3450         }
3451 
3452         /* Return this SACK for further processing.  */
3453         sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_SACK, SCTP_CHUNK(chunk));
3454 
3455         /* Note: We do the rest of the work on the PROCESS_SACK
3456          * sideeffect.
3457          */
3458         return SCTP_DISPOSITION_CONSUME;
3459 }
3460 
3461 /*
3462  * Generate an ABORT in response to a packet.
3463  *
3464  * Section: 8.4 Handle "Out of the blue" Packets, sctpimpguide 2.41
3465  *
3466  * 8) The receiver should respond to the sender of the OOTB packet with
3467  *    an ABORT.  When sending the ABORT, the receiver of the OOTB packet
3468  *    MUST fill in the Verification Tag field of the outbound packet
3469  *    with the value found in the Verification Tag field of the OOTB
3470  *    packet and set the T-bit in the Chunk Flags to indicate that the
3471  *    Verification Tag is reflected.  After sending this ABORT, the
3472  *    receiver of the OOTB packet shall discard the OOTB packet and take
3473  *    no further action.
3474  *
3475  * Verification Tag:
3476  *
3477  * The return value is the disposition of the chunk.
3478 */
3479 static enum sctp_disposition sctp_sf_tabort_8_4_8(
3480                                         struct net *net,
3481                                         const struct sctp_endpoint *ep,
3482                                         const struct sctp_association *asoc,
3483                                         const union sctp_subtype type,
3484                                         void *arg,
3485                                         struct sctp_cmd_seq *commands)
3486 {
3487         struct sctp_packet *packet = NULL;
3488         struct sctp_chunk *chunk = arg;
3489         struct sctp_chunk *abort;
3490 
3491         packet = sctp_ootb_pkt_new(net, asoc, chunk);
3492         if (!packet)
3493                 return SCTP_DISPOSITION_NOMEM;
3494 
3495         /* Make an ABORT. The T bit will be set if the asoc
3496          * is NULL.
3497          */
3498         abort = sctp_make_abort(asoc, chunk, 0);
3499         if (!abort) {
3500                 sctp_ootb_pkt_free(packet);
3501                 return SCTP_DISPOSITION_NOMEM;
3502         }
3503 
3504         /* Reflect vtag if T-Bit is set */
3505         if (sctp_test_T_bit(abort))
3506                 packet->vtag = ntohl(chunk->sctp_hdr->vtag);
3507 
3508         /* Set the skb to the belonging sock for accounting.  */
3509         abort->skb->sk = ep->base.sk;
3510 
3511         sctp_packet_append_chunk(packet, abort);
3512 
3513         sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, SCTP_PACKET(packet));
3514 
3515         SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
3516 
3517         sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3518         return SCTP_DISPOSITION_CONSUME;
3519 }
3520 
3521 /* Handling of SCTP Packets Containing an INIT Chunk Matching an
3522  * Existing Associations when the UDP encap port is incorrect.
3523  *
3524  * From Section 4 at draft-tuexen-tsvwg-sctp-udp-encaps-cons-03.
3525  */
3526 static enum sctp_disposition sctp_sf_new_encap_port(
3527                                         struct net *net,
3528                                         const struct sctp_endpoint *ep,
3529                                         const struct sctp_association *asoc,
3530                                         const union sctp_subtype type,
3531                                         void *arg,
3532                                         struct sctp_cmd_seq *commands)
3533 {
3534         struct sctp_packet *packet = NULL;
3535         struct sctp_chunk *chunk = arg;
3536         struct sctp_chunk *abort;
3537 
3538         packet = sctp_ootb_pkt_new(net, asoc, chunk);
3539         if (!packet)
3540                 return SCTP_DISPOSITION_NOMEM;
3541 
3542         abort = sctp_make_new_encap_port(asoc, chunk);
3543         if (!abort) {
3544                 sctp_ootb_pkt_free(packet);
3545                 return SCTP_DISPOSITION_NOMEM;
3546         }
3547 
3548         abort->skb->sk = ep->base.sk;
3549 
3550         sctp_packet_append_chunk(packet, abort);
3551 
3552         sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
3553                         SCTP_PACKET(packet));
3554 
3555         SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
3556 
3557         sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3558         return SCTP_DISPOSITION_CONSUME;
3559 }
3560 
3561 /*
3562  * Received an ERROR chunk from peer.  Generate SCTP_REMOTE_ERROR
3563  * event as ULP notification for each cause included in the chunk.
3564  *
3565  * API 5.3.1.3 - SCTP_REMOTE_ERROR
3566  *
3567  * The return value is the disposition of the chunk.
3568 */
3569 enum sctp_disposition sctp_sf_operr_notify(struct net *net,
3570                                            const struct sctp_endpoint *ep,
3571                                            const struct sctp_association *asoc,
3572                                            const union sctp_subtype type,
3573                                            void *arg,
3574                                            struct sctp_cmd_seq *commands)
3575 {
3576         struct sctp_chunk *chunk = arg;
3577         struct sctp_errhdr *err;
3578 
3579         if (!sctp_vtag_verify(chunk, asoc))
3580                 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3581 
3582         /* Make sure that the ERROR chunk has a valid length. */
3583         if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_operr_chunk)))
3584                 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3585                                                   commands);
3586         sctp_walk_errors(err, chunk->chunk_hdr);
3587         if ((void *)err != (void *)chunk->chunk_end)
3588                 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg,
3589                                                   (void *)err, commands);
3590 
3591         sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_OPERR,
3592                         SCTP_CHUNK(chunk));
3593 
3594         return SCTP_DISPOSITION_CONSUME;
3595 }
3596 
3597 /*
3598  * Process an inbound SHUTDOWN ACK.
3599  *
3600  * From Section 9.2:
3601  * Upon the receipt of the SHUTDOWN ACK, the SHUTDOWN sender shall
3602  * stop the T2-shutdown timer, send a SHUTDOWN COMPLETE chunk to its
3603  * peer, and remove all record of the association.
3604  *
3605  * The return value is the disposition.
3606  */
3607 enum sctp_disposition sctp_sf_do_9_2_final(struct net *net,
3608                                            const struct sctp_endpoint *ep,
3609                                            const struct sctp_association *asoc,
3610                                            const union sctp_subtype type,
3611                                            void *arg,
3612                                            struct sctp_cmd_seq *commands)
3613 {
3614         struct sctp_chunk *chunk = arg;
3615         struct sctp_chunk *reply;
3616         struct sctp_ulpevent *ev;
3617 
3618         if (!sctp_vtag_verify(chunk, asoc))
3619                 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3620 
3621         /* Make sure that the SHUTDOWN_ACK chunk has a valid length. */
3622         if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr)))
3623                 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3624                                                   commands);
3625         /* 10.2 H) SHUTDOWN COMPLETE notification
3626          *
3627          * When SCTP completes the shutdown procedures (section 9.2) this
3628          * notification is passed to the upper layer.
3629          */
3630         ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_SHUTDOWN_COMP,
3631                                              0, 0, 0, NULL, GFP_ATOMIC);
3632         if (!ev)
3633                 goto nomem;
3634 
3635         /* ...send a SHUTDOWN COMPLETE chunk to its peer, */
3636         reply = sctp_make_shutdown_complete(asoc, chunk);
3637         if (!reply)
3638                 goto nomem_chunk;
3639 
3640         /* Do all the commands now (after allocation), so that we
3641          * have consistent state if memory allocation fails
3642          */
3643         sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev));
3644 
3645         /* Upon the receipt of the SHUTDOWN ACK, the SHUTDOWN sender shall
3646          * stop the T2-shutdown timer,
3647          */
3648         sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
3649                         SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
3650 
3651         sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
3652                         SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
3653 
3654         sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
3655                         SCTP_STATE(SCTP_STATE_CLOSED));
3656         SCTP_INC_STATS(net, SCTP_MIB_SHUTDOWNS);
3657         SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
3658         sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
3659 
3660         /* ...and remove all record of the association. */
3661         sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
3662         return SCTP_DISPOSITION_DELETE_TCB;
3663 
3664 nomem_chunk:
3665         sctp_ulpevent_free(ev);
3666 nomem:
3667         return SCTP_DISPOSITION_NOMEM;
3668 }
3669 
3670 /*
3671  * RFC 2960, 8.4 - Handle "Out of the blue" Packets, sctpimpguide 2.41.
3672  *
3673  * 5) If the packet contains a SHUTDOWN ACK chunk, the receiver should
3674  *    respond to the sender of the OOTB packet with a SHUTDOWN COMPLETE.
3675  *    When sending the SHUTDOWN COMPLETE, the receiver of the OOTB
3676  *    packet must fill in the Verification Tag field of the outbound
3677  *    packet with the Verification Tag received in the SHUTDOWN ACK and
3678  *    set the T-bit in the Chunk Flags to indicate that the Verification
3679  *    Tag is reflected.
3680  *
3681  * 8) The receiver should respond to the sender of the OOTB packet with
3682  *    an ABORT.  When sending the ABORT, the receiver of the OOTB packet
3683  *    MUST fill in the Verification Tag field of the outbound packet
3684  *    with the value found in the Verification Tag field of the OOTB
3685  *    packet and set the T-bit in the Chunk Flags to indicate that the
3686  *    Verification Tag is reflected.  After sending this ABORT, the
3687  *    receiver of the OOTB packet shall discard the OOTB packet and take
3688  *    no further action.
3689  */
3690 enum sctp_disposition sctp_sf_ootb(struct net *net,
3691                                    const struct sctp_endpoint *ep,
3692                                    const struct sctp_association *asoc,
3693                                    const union sctp_subtype type,
3694                                    void *arg, struct sctp_cmd_seq *commands)
3695 {
3696         struct sctp_chunk *chunk = arg;
3697         struct sk_buff *skb = chunk->skb;
3698         struct sctp_chunkhdr *ch;
3699         struct sctp_errhdr *err;
3700         int ootb_cookie_ack = 0;
3701         int ootb_shut_ack = 0;
3702         __u8 *ch_end;
3703 
3704         SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES);
3705 
3706         if (asoc && !sctp_vtag_verify(chunk, asoc))
3707                 asoc = NULL;
3708 
3709         ch = (struct sctp_chunkhdr *)chunk->chunk_hdr;
3710         do {
3711                 /* Report violation if the chunk is less then minimal */
3712                 if (ntohs(ch->length) < sizeof(*ch))
3713                         return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3714                                                   commands);
3715 
3716                 /* Report violation if chunk len overflows */
3717                 ch_end = ((__u8 *)ch) + SCTP_PAD4(ntohs(ch->length));
3718                 if (ch_end > skb_tail_pointer(skb))
3719                         return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3720                                                   commands);
3721 
3722                 /* Now that we know we at least have a chunk header,
3723                  * do things that are type appropriate.
3724                  */
3725                 if (SCTP_CID_SHUTDOWN_ACK == ch->type)
3726                         ootb_shut_ack = 1;
3727 
3728                 /* RFC 2960, Section 3.3.7
3729                  *   Moreover, under any circumstances, an endpoint that
3730                  *   receives an ABORT  MUST NOT respond to that ABORT by
3731                  *   sending an ABORT of its own.
3732                  */
3733                 if (SCTP_CID_ABORT == ch->type)
3734                         return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3735 
3736                 /* RFC 8.4, 7) If the packet contains a "Stale cookie" ERROR
3737                  * or a COOKIE ACK the SCTP Packet should be silently
3738                  * discarded.
3739                  */
3740 
3741                 if (SCTP_CID_COOKIE_ACK == ch->type)
3742                         ootb_cookie_ack = 1;
3743 
3744                 if (SCTP_CID_ERROR == ch->type) {
3745                         sctp_walk_errors(err, ch) {
3746                                 if (SCTP_ERROR_STALE_COOKIE == err->cause) {
3747                                         ootb_cookie_ack = 1;
3748                                         break;
3749                                 }
3750                         }
3751                 }
3752 
3753                 ch = (struct sctp_chunkhdr *)ch_end;
3754         } while (ch_end < skb_tail_pointer(skb));
3755 
3756         if (ootb_shut_ack)
3757                 return sctp_sf_shut_8_4_5(net, ep, asoc, type, arg, commands);
3758         else if (ootb_cookie_ack)
3759                 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3760         else
3761                 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands);
3762 }
3763 
3764 /*
3765  * Handle an "Out of the blue" SHUTDOWN ACK.
3766  *
3767  * Section: 8.4 5, sctpimpguide 2.41.
3768  *
3769  * 5) If the packet contains a SHUTDOWN ACK chunk, the receiver should
3770  *    respond to the sender of the OOTB packet with a SHUTDOWN COMPLETE.
3771  *    When sending the SHUTDOWN COMPLETE, the receiver of the OOTB
3772  *    packet must fill in the Verification Tag field of the outbound
3773  *    packet with the Verification Tag received in the SHUTDOWN ACK and
3774  *    set the T-bit in the Chunk Flags to indicate that the Verification
3775  *    Tag is reflected.
3776  *
3777  * Inputs
3778  * (endpoint, asoc, type, arg, commands)
3779  *
3780  * Outputs
3781  * (enum sctp_disposition)
3782  *
3783  * The return value is the disposition of the chunk.
3784  */
3785 static enum sctp_disposition sctp_sf_shut_8_4_5(
3786                                         struct net *net,
3787                                         const struct sctp_endpoint *ep,
3788                                         const struct sctp_association *asoc,
3789                                         const union sctp_subtype type,
3790                                         void *arg,
3791                                         struct sctp_cmd_seq *commands)
3792 {
3793         struct sctp_packet *packet = NULL;
3794         struct sctp_chunk *chunk = arg;
3795         struct sctp_chunk *shut;
3796 
3797         packet = sctp_ootb_pkt_new(net, asoc, chunk);
3798         if (!packet)
3799                 return SCTP_DISPOSITION_NOMEM;
3800 
3801         /* Make an SHUTDOWN_COMPLETE.
3802          * The T bit will be set if the asoc is NULL.
3803          */
3804         shut = sctp_make_shutdown_complete(asoc, chunk);
3805         if (!shut) {
3806                 sctp_ootb_pkt_free(packet);
3807                 return SCTP_DISPOSITION_NOMEM;
3808         }
3809 
3810         /* Reflect vtag if T-Bit is set */
3811         if (sctp_test_T_bit(shut))
3812                 packet->vtag = ntohl(chunk->sctp_hdr->vtag);
3813 
3814         /* Set the skb to the belonging sock for accounting.  */
3815         shut->skb->sk = ep->base.sk;
3816 
3817         sctp_packet_append_chunk(packet, shut);
3818 
3819         sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
3820                         SCTP_PACKET(packet));
3821 
3822         SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
3823 
3824         /* We need to discard the rest of the packet to prevent
3825          * potential boomming attacks from additional bundled chunks.
3826          * This is documented in SCTP Threats ID.
3827          */
3828         return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3829 }
3830 
3831 /*
3832  * Handle SHUTDOWN ACK in COOKIE_ECHOED or COOKIE_WAIT state.
3833  *
3834  * Verification Tag:  8.5.1 E) Rules for packet carrying a SHUTDOWN ACK
3835  *   If the receiver is in COOKIE-ECHOED or COOKIE-WAIT state the
3836  *   procedures in section 8.4 SHOULD be followed, in other words it
3837  *   should be treated as an Out Of The Blue packet.
3838  *   [This means that we do NOT check the Verification Tag on these
3839  *   chunks. --piggy ]
3840  *
3841  */
3842 enum sctp_disposition sctp_sf_do_8_5_1_E_sa(struct net *net,
3843                                             const struct sctp_endpoint *ep,
3844                                             const struct sctp_association *asoc,
3845                                             const union sctp_subtype type,
3846                                             void *arg,
3847                                             struct sctp_cmd_seq *commands)
3848 {
3849         struct sctp_chunk *chunk = arg;
3850 
3851         if (!sctp_vtag_verify(chunk, asoc))
3852                 asoc = NULL;
3853 
3854         /* Make sure that the SHUTDOWN_ACK chunk has a valid length. */
3855         if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr)))
3856                 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3857                                                   commands);
3858 
3859         /* Although we do have an association in this case, it corresponds
3860          * to a restarted association. So the packet is treated as an OOTB
3861          * packet and the state function that handles OOTB SHUTDOWN_ACK is
3862          * called with a NULL association.
3863          */
3864         SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES);
3865 
3866         return sctp_sf_shut_8_4_5(net, ep, NULL, type, arg, commands);
3867 }
3868 
3869 /* ADDIP Section 4.2 Upon reception of an ASCONF Chunk.  */
3870 enum sctp_disposition sctp_sf_do_asconf(struct net *net,
3871                                         const struct sctp_endpoint *ep,
3872                                         const struct sctp_association *asoc,
3873                                         const union sctp_subtype type,
3874                                         void *arg,
3875                                         struct sctp_cmd_seq *commands)
3876 {
3877         struct sctp_paramhdr *err_param = NULL;
3878         struct sctp_chunk *asconf_ack = NULL;
3879         struct sctp_chunk *chunk = arg;
3880         struct sctp_addiphdr *hdr;
3881         __u32 serial;
3882 
3883         if (!sctp_vtag_verify(chunk, asoc)) {
3884                 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
3885                                 SCTP_NULL());
3886                 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3887         }
3888 
3889         /* Make sure that the ASCONF ADDIP chunk has a valid length.  */
3890         if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_addip_chunk)))
3891                 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
3892                                                   commands);
3893 
3894         /* ADD-IP: Section 4.1.1
3895          * This chunk MUST be sent in an authenticated way by using
3896          * the mechanism defined in [I-D.ietf-tsvwg-sctp-auth]. If this chunk
3897          * is received unauthenticated it MUST be silently discarded as
3898          * described in [I-D.ietf-tsvwg-sctp-auth].
3899          */
3900         if (!asoc->peer.asconf_capable ||
3901             (!net->sctp.addip_noauth && !chunk->auth))
3902                 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
3903 
3904         hdr = (struct sctp_addiphdr *)chunk->skb->data;
3905         serial = ntohl(hdr->serial);
3906 
3907         /* Verify the ASCONF chunk before processing it. */
3908         if (!sctp_verify_asconf(asoc, chunk, true, &err_param))
3909                 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg,
3910                                                   (void *)err_param, commands);
3911 
3912         /* ADDIP 5.2 E1) Compare the value of the serial number to the value
3913          * the endpoint stored in a new association variable
3914          * 'Peer-Serial-Number'.
3915          */
3916         if (serial == asoc->peer.addip_serial + 1) {
3917                 /* If this is the first instance of ASCONF in the packet,
3918                  * we can clean our old ASCONF-ACKs.
3919                  */
3920                 if (!chunk->has_asconf)
3921                         sctp_assoc_clean_asconf_ack_cache(asoc);
3922 
3923                 /* ADDIP 5.2 E4) When the Sequence Number matches the next one
3924                  * expected, process the ASCONF as described below and after
3925                  * processing the ASCONF Chunk, append an ASCONF-ACK Chunk to
3926                  * the response packet and cache a copy of it (in the event it
3927                  * later needs to be retransmitted).
3928                  *
3929                  * Essentially, do V1-V5.
3930                  */
3931                 asconf_ack = sctp_process_asconf((struct sctp_association *)
3932                                                  asoc, chunk);
3933                 if (!asconf_ack)
3934                         return SCTP_DISPOSITION_NOMEM;
3935         } else if (serial < asoc->peer.addip_serial + 1) {
3936                 /* ADDIP 5.2 E2)
3937                  * If the value found in the Sequence Number is less than the
3938                  * ('Peer- Sequence-Number' + 1), simply skip to the next
3939                  * ASCONF, and include in the outbound response packet
3940                  * any previously cached ASCONF-ACK response that was
3941                  * sent and saved that matches the Sequence Number of the
3942                  * ASCONF.  Note: It is possible that no cached ASCONF-ACK
3943                  * Chunk exists.  This will occur when an older ASCONF
3944                  * arrives out of order.  In such a case, the receiver
3945                  * should skip the ASCONF Chunk and not include ASCONF-ACK
3946                  * Chunk for that chunk.
3947                  */
3948                 asconf_ack = sctp_assoc_lookup_asconf_ack(asoc, hdr->serial);
3949                 if (!asconf_ack)
3950                         return SCTP_DISPOSITION_DISCARD;
3951 
3952                 /* Reset the transport so that we select the correct one
3953                  * this time around.  This is to make sure that we don't
3954                  * accidentally use a stale transport that's been removed.
3955                  */
3956                 asconf_ack->transport = NULL;
3957         } else {
3958                 /* ADDIP 5.2 E5) Otherwise, the ASCONF Chunk is discarded since
3959                  * it must be either a stale packet or from an attacker.
3960                  */
3961                 return SCTP_DISPOSITION_DISCARD;
3962         }
3963 
3964         /* ADDIP 5.2 E6)  The destination address of the SCTP packet
3965          * containing the ASCONF-ACK Chunks MUST be the source address of
3966          * the SCTP packet that held the ASCONF Chunks.
3967          *
3968          * To do this properly, we'll set the destination address of the chunk
3969          * and at the transmit time, will try look up the transport to use.
3970          * Since ASCONFs may be bundled, the correct transport may not be
3971          * created until we process the entire packet, thus this workaround.
3972          */
3973         asconf_ack->dest = chunk->source;
3974         sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(asconf_ack));
3975         if (asoc->new_transport) {
3976                 sctp_sf_heartbeat(ep, asoc, type, asoc->new_transport, commands);
3977                 ((struct sctp_association *)asoc)->new_transport = NULL;
3978         }
3979 
3980         return SCTP_DISPOSITION_CONSUME;
3981 }
3982 
3983 static enum sctp_disposition sctp_send_next_asconf(
3984                                         struct net *net,
3985                                         const struct sctp_endpoint *ep,
3986                                         struct sctp_association *asoc,
3987                                         const union sctp_subtype type,
3988                                         struct sctp_cmd_seq *commands)
3989 {
3990         struct sctp_chunk *asconf;
3991         struct list_head *entry;
3992 
3993         if (list_empty(&asoc->addip_chunk_list))
3994                 return SCTP_DISPOSITION_CONSUME;
3995 
3996         entry = asoc->addip_chunk_list.next;
3997         asconf = list_entry(entry, struct sctp_chunk, list);
3998 
3999         list_del_init(entry);
4000         sctp_chunk_hold(asconf);
4001         asoc->addip_last_asconf = asconf;
4002 
4003         return sctp_sf_do_prm_asconf(net, ep, asoc, type, asconf, commands);
4004 }
4005 
4006 /*
4007  * ADDIP Section 4.3 General rules for address manipulation
4008  * When building TLV parameters for the ASCONF Chunk that will add or
4009  * delete IP addresses the D0 to D13 rules should be applied:
4010  */
4011 enum sctp_disposition sctp_sf_do_asconf_ack(struct net *net,
4012                                             const struct sctp_endpoint *ep,
4013                                             const struct sctp_association *asoc,
4014                                             const union sctp_subtype type,
4015                                             void *arg,
4016                                             struct sctp_cmd_seq *commands)
4017 {
4018         struct sctp_chunk *last_asconf = asoc->addip_last_asconf;
4019         struct sctp_paramhdr *err_param = NULL;
4020         struct sctp_chunk *asconf_ack = arg;
4021         struct sctp_addiphdr *addip_hdr;
4022         __u32 sent_serial, rcvd_serial;
4023         struct sctp_chunk *abort;
4024 
4025         if (!sctp_vtag_verify(asconf_ack, asoc)) {
4026                 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
4027                                 SCTP_NULL());
4028                 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
4029         }
4030 
4031         /* Make sure that the ADDIP chunk has a valid length.  */
4032         if (!sctp_chunk_length_valid(asconf_ack,
4033                                      sizeof(struct sctp_addip_chunk)))
4034                 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
4035                                                   commands);
4036 
4037         /* ADD-IP, Section 4.1.2:
4038          * This chunk MUST be sent in an authenticated way by using
4039          * the mechanism defined in [I-D.ietf-tsvwg-sctp-auth]. If this chunk
4040          * is received unauthenticated it MUST be silently discarded as
4041          * described in [I-D.ietf-tsvwg-sctp-auth].
4042          */
4043         if (!asoc->peer.asconf_capable ||
4044             (!net->sctp.addip_noauth && !asconf_ack->auth))
4045                 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
4046 
4047         addip_hdr = (struct sctp_addiphdr *)asconf_ack->skb->data;
4048         rcvd_serial = ntohl(addip_hdr->serial);
4049 
4050         /* Verify the ASCONF-ACK chunk before processing it. */
4051         if (!sctp_verify_asconf(asoc, asconf_ack, false, &err_param))
4052                 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg,
4053                            (void *)err_param, commands);
4054 
4055         if (last_asconf) {
4056                 addip_hdr = last_asconf->subh.addip_hdr;
4057                 sent_serial = ntohl(addip_hdr->serial);
4058         } else {
4059                 sent_serial = asoc->addip_serial - 1;
4060         }
4061 
4062         /* D0) If an endpoint receives an ASCONF-ACK that is greater than or
4063          * equal to the next serial number to be used but no ASCONF chunk is
4064          * outstanding the endpoint MUST ABORT the association. Note that a
4065          * sequence number is greater than if it is no more than 2^^31-1
4066          * larger than the current sequence number (using serial arithmetic).
4067          */
4068         if (ADDIP_SERIAL_gte(rcvd_serial, sent_serial + 1) &&
4069             !(asoc->addip_last_asconf)) {
4070                 abort = sctp_make_abort(asoc, asconf_ack,
4071                                         sizeof(struct sctp_errhdr));
4072                 if (abort) {
4073                         sctp_init_cause(abort, SCTP_ERROR_ASCONF_ACK, 0);
4074                         sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
4075                                         SCTP_CHUNK(abort));
4076                 }
4077                 /* We are going to ABORT, so we might as well stop
4078                  * processing the rest of the chunks in the packet.
4079                  */
4080                 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
4081                                 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
4082                 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL());
4083                 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
4084                                 SCTP_ERROR(ECONNABORTED));
4085                 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
4086                                 SCTP_PERR(SCTP_ERROR_ASCONF_ACK));
4087                 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
4088                 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
4089                 return SCTP_DISPOSITION_ABORT;
4090         }
4091 
4092         if ((rcvd_serial == sent_serial) && asoc->addip_last_asconf) {
4093                 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
4094                                 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
4095 
4096                 if (!sctp_process_asconf_ack((struct sctp_association *)asoc,
4097                                              asconf_ack))
4098                         return sctp_send_next_asconf(net, ep,
4099                                         (struct sctp_association *)asoc,
4100                                                         type, commands);
4101 
4102                 abort = sctp_make_abort(asoc, asconf_ack,
4103                                         sizeof(struct sctp_errhdr));
4104                 if (abort) {
4105                         sctp_init_cause(abort, SCTP_ERROR_RSRC_LOW, 0);
4106                         sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
4107                                         SCTP_CHUNK(abort));
4108                 }
4109                 /* We are going to ABORT, so we might as well stop
4110                  * processing the rest of the chunks in the packet.
4111                  */
4112                 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL());
4113                 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
4114                                 SCTP_ERROR(ECONNABORTED));
4115                 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
4116                                 SCTP_PERR(SCTP_ERROR_ASCONF_ACK));
4117                 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
4118                 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
4119                 return SCTP_DISPOSITION_ABORT;
4120         }
4121 
4122         return SCTP_DISPOSITION_DISCARD;
4123 }
4124 
4125 /* RE-CONFIG Section 5.2 Upon reception of an RECONF Chunk. */
4126 enum sctp_disposition sctp_sf_do_reconf(struct net *net,
4127                                         const struct sctp_endpoint *ep,
4128                                         const struct sctp_association *asoc,
4129                                         const union sctp_subtype type,
4130                                         void *arg,
4131                                         struct sctp_cmd_seq *commands)
4132 {
4133         struct sctp_paramhdr *err_param = NULL;
4134         struct sctp_chunk *chunk = arg;
4135         struct sctp_reconf_chunk *hdr;
4136         union sctp_params param;
4137 
4138         if (!sctp_vtag_verify(chunk, asoc)) {
4139                 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
4140                                 SCTP_NULL());
4141                 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
4142         }
4143 
4144         /* Make sure that the RECONF chunk has a valid length.  */
4145         if (!sctp_chunk_length_valid(chunk, sizeof(*hdr)))
4146                 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
4147                                                   commands);
4148 
4149         if (!sctp_verify_reconf(asoc, chunk, &err_param))
4150                 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg,
4151                                                   (void *)err_param, commands);
4152 
4153         hdr = (struct sctp_reconf_chunk *)chunk->chunk_hdr;
4154         sctp_walk_params(param, hdr) {
4155                 struct sctp_chunk *reply = NULL;
4156                 struct sctp_ulpevent *ev = NULL;
4157 
4158                 if (param.p->type == SCTP_PARAM_RESET_OUT_REQUEST)
4159                         reply = sctp_process_strreset_outreq(
4160                                 (struct sctp_association *)asoc, param, &ev);
4161                 else if (param.p->type == SCTP_PARAM_RESET_IN_REQUEST)
4162                         reply = sctp_process_strreset_inreq(
4163                                 (struct sctp_association *)asoc, param, &ev);
4164                 else if (param.p->type == SCTP_PARAM_RESET_TSN_REQUEST)
4165                         reply = sctp_process_strreset_tsnreq(
4166                                 (struct sctp_association *)asoc, param, &ev);
4167                 else if (param.p->type == SCTP_PARAM_RESET_ADD_OUT_STREAMS)
4168                         reply = sctp_process_strreset_addstrm_out(
4169                                 (struct sctp_association *)asoc, param, &ev);
4170                 else if (param.p->type == SCTP_PARAM_RESET_ADD_IN_STREAMS)
4171                         reply = sctp_process_strreset_addstrm_in(
4172                                 (struct sctp_association *)asoc, param, &ev);
4173                 else if (param.p->type == SCTP_PARAM_RESET_RESPONSE)
4174                         reply = sctp_process_strreset_resp(
4175                                 (struct sctp_association *)asoc, param, &ev);
4176 
4177                 if (ev)
4178                         sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
4179                                         SCTP_ULPEVENT(ev));
4180 
4181                 if (reply)
4182                         sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
4183                                         SCTP_CHUNK(reply));
4184         }
4185 
4186         return SCTP_DISPOSITION_CONSUME;
4187 }
4188 
4189 /*
4190  * PR-SCTP Section 3.6 Receiver Side Implementation of PR-SCTP
4191  *
4192  * When a FORWARD TSN chunk arrives, the data receiver MUST first update
4193  * its cumulative TSN point to the value carried in the FORWARD TSN
4194  * chunk, and then MUST further advance its cumulative TSN point locally
4195  * if possible.
4196  * After the above processing, the data receiver MUST stop reporting any
4197  * missing TSNs earlier than or equal to the new cumulative TSN point.
4198  *
4199  * Verification Tag:  8.5 Verification Tag [Normal verification]
4200  *
4201  * The return value is the disposition of the chunk.
4202  */
4203 enum sctp_disposition sctp_sf_eat_fwd_tsn(struct net *net,
4204                                           const struct sctp_endpoint *ep,
4205                                           const struct sctp_association *asoc,
4206                                           const union sctp_subtype type,
4207                                           void *arg,
4208                                           struct sctp_cmd_seq *commands)
4209 {
4210         struct sctp_fwdtsn_hdr *fwdtsn_hdr;
4211         struct sctp_chunk *chunk = arg;
4212         __u16 len;
4213         __u32 tsn;
4214 
4215         if (!sctp_vtag_verify(chunk, asoc)) {
4216                 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
4217                                 SCTP_NULL());
4218                 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
4219         }
4220 
4221         if (!asoc->peer.prsctp_capable)
4222                 return sctp_sf_unk_chunk(net, ep, asoc, type, arg, commands);
4223 
4224         /* Make sure that the FORWARD_TSN chunk has valid length.  */
4225         if (!sctp_chunk_length_valid(chunk, sctp_ftsnchk_len(&asoc->stream)))
4226                 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
4227                                                   commands);
4228 
4229         fwdtsn_hdr = (struct sctp_fwdtsn_hdr *)chunk->skb->data;
4230         chunk->subh.fwdtsn_hdr = fwdtsn_hdr;
4231         len = ntohs(chunk->chunk_hdr->length);
4232         len -= sizeof(struct sctp_chunkhdr);
4233         skb_pull(chunk->skb, len);
4234 
4235         tsn = ntohl(fwdtsn_hdr->new_cum_tsn);
4236         pr_debug("%s: TSN 0x%x\n", __func__, tsn);
4237 
4238         /* The TSN is too high--silently discard the chunk and count on it
4239          * getting retransmitted later.
4240          */
4241         if (sctp_tsnmap_check(&asoc->peer.tsn_map, tsn) < 0)
4242                 goto discard_noforce;
4243 
4244         if (!asoc->stream.si->validate_ftsn(chunk))
4245                 goto discard_noforce;
4246 
4247         sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_FWDTSN, SCTP_U32(tsn));
4248         if (len > sctp_ftsnhdr_len(&asoc->stream))
4249                 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_FWDTSN,
4250                                 SCTP_CHUNK(chunk));
4251 
4252         /* Count this as receiving DATA. */
4253         if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) {
4254                 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
4255                                 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
4256         }
4257 
4258         /* FIXME: For now send a SACK, but DATA processing may
4259          * send another.
4260          */
4261         sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_NOFORCE());
4262 
4263         return SCTP_DISPOSITION_CONSUME;
4264 
4265 discard_noforce:
4266         return SCTP_DISPOSITION_DISCARD;
4267 }
4268 
4269 enum sctp_disposition sctp_sf_eat_fwd_tsn_fast(
4270                                         struct net *net,
4271                                         const struct sctp_endpoint *ep,
4272                                         const struct sctp_association *asoc,
4273                                         const union sctp_subtype type,
4274                                         void *arg,
4275                                         struct sctp_cmd_seq *commands)
4276 {
4277         struct sctp_fwdtsn_hdr *fwdtsn_hdr;
4278         struct sctp_chunk *chunk = arg;
4279         __u16 len;
4280         __u32 tsn;
4281 
4282         if (!sctp_vtag_verify(chunk, asoc)) {
4283                 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
4284                                 SCTP_NULL());
4285                 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
4286         }
4287 
4288         if (!asoc->peer.prsctp_capable)
4289                 return sctp_sf_unk_chunk(net, ep, asoc, type, arg, commands);
4290 
4291         /* Make sure that the FORWARD_TSN chunk has a valid length.  */
4292         if (!sctp_chunk_length_valid(chunk, sctp_ftsnchk_len(&asoc->stream)))
4293                 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
4294                                                   commands);
4295 
4296         fwdtsn_hdr = (struct sctp_fwdtsn_hdr *)chunk->skb->data;
4297         chunk->subh.fwdtsn_hdr = fwdtsn_hdr;
4298         len = ntohs(chunk->chunk_hdr->length);
4299         len -= sizeof(struct sctp_chunkhdr);
4300         skb_pull(chunk->skb, len);
4301 
4302         tsn = ntohl(fwdtsn_hdr->new_cum_tsn);
4303         pr_debug("%s: TSN 0x%x\n", __func__, tsn);
4304 
4305         /* The TSN is too high--silently discard the chunk and count on it
4306          * getting retransmitted later.
4307          */
4308         if (sctp_tsnmap_check(&asoc->peer.tsn_map, tsn) < 0)
4309                 goto gen_shutdown;
4310 
4311         if (!asoc->stream.si->validate_ftsn(chunk))
4312                 goto gen_shutdown;
4313 
4314         sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_FWDTSN, SCTP_U32(tsn));
4315         if (len > sctp_ftsnhdr_len(&asoc->stream))
4316                 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_FWDTSN,
4317                                 SCTP_CHUNK(chunk));
4318 
4319         /* Go a head and force a SACK, since we are shutting down. */
4320 gen_shutdown:
4321         /* Implementor's Guide.
4322          *
4323          * While in SHUTDOWN-SENT state, the SHUTDOWN sender MUST immediately
4324          * respond to each received packet containing one or more DATA chunk(s)
4325          * with a SACK, a SHUTDOWN chunk, and restart the T2-shutdown timer
4326          */
4327         sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SHUTDOWN, SCTP_NULL());
4328         sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE());
4329         sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
4330                         SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
4331 
4332         return SCTP_DISPOSITION_CONSUME;
4333 }
4334 
4335 /*
4336  * SCTP-AUTH Section 6.3 Receiving authenticated chunks
4337  *
4338  *    The receiver MUST use the HMAC algorithm indicated in the HMAC
4339  *    Identifier field.  If this algorithm was not specified by the
4340  *    receiver in the HMAC-ALGO parameter in the INIT or INIT-ACK chunk
4341  *    during association setup, the AUTH chunk and all chunks after it MUST
4342  *    be discarded and an ERROR chunk SHOULD be sent with the error cause
4343  *    defined in Section 4.1.
4344  *
4345  *    If an endpoint with no shared key receives a Shared Key Identifier
4346  *    other than 0, it MUST silently discard all authenticated chunks.  If
4347  *    the endpoint has at least one endpoint pair shared key for the peer,
4348  *    it MUST use the key specified by the Shared Key Identifier if a
4349  *    key has been configured for that Shared Key Identifier.  If no
4350  *    endpoint pair shared key has been configured for that Shared Key
4351  *    Identifier, all authenticated chunks MUST be silently discarded.
4352  *
4353  * Verification Tag:  8.5 Verification Tag [Normal verification]
4354  *
4355  * The return value is the disposition of the chunk.
4356  */
4357 static enum sctp_ierror sctp_sf_authenticate(
4358                                         const struct sctp_association *asoc,
4359                                         struct sctp_chunk *chunk)
4360 {
4361         struct sctp_shared_key *sh_key = NULL;
4362         struct sctp_authhdr *auth_hdr;
4363         __u8 *save_digest, *digest;
4364         struct sctp_hmac *hmac;
4365         unsigned int sig_len;
4366         __u16 key_id;
4367 
4368         /* Pull in the auth header, so we can do some more verification */
4369         auth_hdr = (struct sctp_authhdr *)chunk->skb->data;
4370         chunk->subh.auth_hdr = auth_hdr;
4371         skb_pull(chunk->skb, sizeof(*auth_hdr));
4372 
4373         /* Make sure that we support the HMAC algorithm from the auth
4374          * chunk.
4375          */
4376         if (!sctp_auth_asoc_verify_hmac_id(asoc, auth_hdr->hmac_id))
4377                 return SCTP_IERROR_AUTH_BAD_HMAC;
4378 
4379         /* Make sure that the provided shared key identifier has been
4380          * configured
4381          */
4382         key_id = ntohs(auth_hdr->shkey_id);
4383         if (key_id != asoc->active_key_id) {
4384                 sh_key = sctp_auth_get_shkey(asoc, key_id);
4385                 if (!sh_key)
4386                         return SCTP_IERROR_AUTH_BAD_KEYID;
4387         }
4388 
4389         /* Make sure that the length of the signature matches what
4390          * we expect.
4391          */
4392         sig_len = ntohs(chunk->chunk_hdr->length) -
4393                   sizeof(struct sctp_auth_chunk);
4394         hmac = sctp_auth_get_hmac(ntohs(auth_hdr->hmac_id));
4395         if (sig_len != hmac->hmac_len)
4396                 return SCTP_IERROR_PROTO_VIOLATION;
4397 
4398         /* Now that we've done validation checks, we can compute and
4399          * verify the hmac.  The steps involved are:
4400          *  1. Save the digest from the chunk.
4401          *  2. Zero out the digest in the chunk.
4402          *  3. Compute the new digest
4403          *  4. Compare saved and new digests.
4404          */
4405         digest = (u8 *)(auth_hdr + 1);
4406         skb_pull(chunk->skb, sig_len);
4407 
4408         save_digest = kmemdup(digest, sig_len, GFP_ATOMIC);
4409         if (!save_digest)
4410                 goto nomem;
4411 
4412         memset(digest, 0, sig_len);
4413 
4414         sctp_auth_calculate_hmac(asoc, chunk->skb,
4415                                  (struct sctp_auth_chunk *)chunk->chunk_hdr,
4416                                  sh_key, GFP_ATOMIC);
4417 
4418         /* Discard the packet if the digests do not match */
4419         if (memcmp(save_digest, digest, sig_len)) {
4420                 kfree(save_digest);
4421                 return SCTP_IERROR_BAD_SIG;
4422         }
4423 
4424         kfree(save_digest);
4425         chunk->auth = 1;
4426 
4427         return SCTP_IERROR_NO_ERROR;
4428 nomem:
4429         return SCTP_IERROR_NOMEM;
4430 }
4431 
4432 enum sctp_disposition sctp_sf_eat_auth(struct net *net,
4433                                        const struct sctp_endpoint *ep,
4434                                        const struct sctp_association *asoc,
4435                                        const union sctp_subtype type,
4436                                        void *arg, struct sctp_cmd_seq *commands)
4437 {
4438         struct sctp_chunk *chunk = arg;
4439         struct sctp_authhdr *auth_hdr;
4440         struct sctp_chunk *err_chunk;
4441         enum sctp_ierror error;
4442 
4443         /* Make sure that the peer has AUTH capable */
4444         if (!asoc->peer.auth_capable)
4445                 return sctp_sf_unk_chunk(net, ep, asoc, type, arg, commands);
4446 
4447         if (!sctp_vtag_verify(chunk, asoc)) {
4448                 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG,
4449                                 SCTP_NULL());
4450                 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
4451         }
4452 
4453         /* Make sure that the AUTH chunk has valid length.  */
4454         if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_auth_chunk)))
4455                 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
4456                                                   commands);
4457 
4458         auth_hdr = (struct sctp_authhdr *)chunk->skb->data;
4459         error = sctp_sf_authenticate(asoc, chunk);
4460         switch (error) {
4461         case SCTP_IERROR_AUTH_BAD_HMAC:
4462                 /* Generate the ERROR chunk and discard the rest
4463                  * of the packet
4464                  */
4465                 err_chunk = sctp_make_op_error(asoc, chunk,
4466                                                SCTP_ERROR_UNSUP_HMAC,
4467                                                &auth_hdr->hmac_id,
4468                                                sizeof(__u16), 0);
4469                 if (err_chunk) {
4470                         sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
4471                                         SCTP_CHUNK(err_chunk));
4472                 }
4473                 fallthrough;
4474         case SCTP_IERROR_AUTH_BAD_KEYID:
4475         case SCTP_IERROR_BAD_SIG:
4476                 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
4477 
4478         case SCTP_IERROR_PROTO_VIOLATION:
4479                 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
4480                                                   commands);
4481 
4482         case SCTP_IERROR_NOMEM:
4483                 return SCTP_DISPOSITION_NOMEM;
4484 
4485         default:                        /* Prevent gcc warnings */
4486                 break;
4487         }
4488 
4489         if (asoc->active_key_id != ntohs(auth_hdr->shkey_id)) {
4490                 struct sctp_ulpevent *ev;
4491 
4492                 ev = sctp_ulpevent_make_authkey(asoc, ntohs(auth_hdr->shkey_id),
4493                                     SCTP_AUTH_NEW_KEY, GFP_ATOMIC);
4494 
4495                 if (!ev)
4496                         return SCTP_DISPOSITION_NOMEM;
4497 
4498                 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP,
4499                                 SCTP_ULPEVENT(ev));
4500         }
4501 
4502         return SCTP_DISPOSITION_CONSUME;
4503 }
4504 
4505 /*
4506  * Process an unknown chunk.
4507  *
4508  * Section: 3.2. Also, 2.1 in the implementor's guide.
4509  *
4510  * Chunk Types are encoded such that the highest-order two bits specify
4511  * the action that must be taken if the processing endpoint does not
4512  * recognize the Chunk Type.
4513  *
4514  * 00 - Stop processing this SCTP packet and discard it, do not process
4515  *      any further chunks within it.
4516  *
4517  * 01 - Stop processing this SCTP packet and discard it, do not process
4518  *      any further chunks within it, and report the unrecognized
4519  *      chunk in an 'Unrecognized Chunk Type'.
4520  *
4521  * 10 - Skip this chunk and continue processing.
4522  *
4523  * 11 - Skip this chunk and continue processing, but report in an ERROR
4524  *      Chunk using the 'Unrecognized Chunk Type' cause of error.
4525  *
4526  * The return value is the disposition of the chunk.
4527  */
4528 enum sctp_disposition sctp_sf_unk_chunk(struct net *net,
4529                                         const struct sctp_endpoint *ep,
4530                                         const struct sctp_association *asoc,
4531                                         const union sctp_subtype type,
4532                                         void *arg,
4533                                         struct sctp_cmd_seq *commands)
4534 {
4535         struct sctp_chunk *unk_chunk = arg;
4536         struct sctp_chunk *err_chunk;
4537         struct sctp_chunkhdr *hdr;
4538 
4539         pr_debug("%s: processing unknown chunk id:%d\n", __func__, type.chunk);
4540 
4541         if (!sctp_vtag_verify(unk_chunk, asoc))
4542                 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
4543 
4544         /* Make sure that the chunk has a valid length.
4545          * Since we don't know the chunk type, we use a general
4546          * chunkhdr structure to make a comparison.
4547          */
4548         if (!sctp_chunk_length_valid(unk_chunk, sizeof(*hdr)))
4549                 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
4550                                                   commands);
4551 
4552         switch (type.chunk & SCTP_CID_ACTION_MASK) {
4553         case SCTP_CID_ACTION_DISCARD:
4554                 /* Discard the packet.  */
4555                 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
4556         case SCTP_CID_ACTION_DISCARD_ERR:
4557                 /* Generate an ERROR chunk as response. */
4558                 hdr = unk_chunk->chunk_hdr;
4559                 err_chunk = sctp_make_op_error(asoc, unk_chunk,
4560                                                SCTP_ERROR_UNKNOWN_CHUNK, hdr,
4561                                                SCTP_PAD4(ntohs(hdr->length)),
4562                                                0);
4563                 if (err_chunk) {
4564                         sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
4565                                         SCTP_CHUNK(err_chunk));
4566                 }
4567 
4568                 /* Discard the packet.  */
4569                 sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
4570                 return SCTP_DISPOSITION_CONSUME;
4571         case SCTP_CID_ACTION_SKIP:
4572                 /* Skip the chunk.  */
4573                 return SCTP_DISPOSITION_DISCARD;
4574         case SCTP_CID_ACTION_SKIP_ERR:
4575                 /* Generate an ERROR chunk as response. */
4576                 hdr = unk_chunk->chunk_hdr;
4577                 err_chunk = sctp_make_op_error(asoc, unk_chunk,
4578                                                SCTP_ERROR_UNKNOWN_CHUNK, hdr,
4579                                                SCTP_PAD4(ntohs(hdr->length)),
4580                                                0);
4581                 if (err_chunk) {
4582                         sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
4583                                         SCTP_CHUNK(err_chunk));
4584                 }
4585                 /* Skip the chunk.  */
4586                 return SCTP_DISPOSITION_CONSUME;
4587         default:
4588                 break;
4589         }
4590 
4591         return SCTP_DISPOSITION_DISCARD;
4592 }
4593 
4594 /*
4595  * Discard the chunk.
4596  *
4597  * Section: 0.2, 5.2.3, 5.2.5, 5.2.6, 6.0, 8.4.6, 8.5.1c, 9.2
4598  * [Too numerous to mention...]
4599  * Verification Tag: No verification needed.
4600  * Inputs
4601  * (endpoint, asoc, chunk)
4602  *
4603  * Outputs
4604  * (asoc, reply_msg, msg_up, timers, counters)
4605  *
4606  * The return value is the disposition of the chunk.
4607  */
4608 enum sctp_disposition sctp_sf_discard_chunk(struct net *net,
4609                                             const struct sctp_endpoint *ep,
4610                                             const struct sctp_association *asoc,
4611                                             const union sctp_subtype type,
4612                                             void *arg,
4613                                             struct sctp_cmd_seq *commands)
4614 {
4615         struct sctp_chunk *chunk = arg;
4616 
4617         if (asoc && !sctp_vtag_verify(chunk, asoc))
4618                 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
4619 
4620         /* Make sure that the chunk has a valid length.
4621          * Since we don't know the chunk type, we use a general
4622          * chunkhdr structure to make a comparison.
4623          */
4624         if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr)))
4625                 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
4626                                                   commands);
4627 
4628         pr_debug("%s: chunk:%d is discarded\n", __func__, type.chunk);
4629 
4630         return SCTP_DISPOSITION_DISCARD;
4631 }
4632 
4633 /*
4634  * Discard the whole packet.
4635  *
4636  * Section: 8.4 2)
4637  *
4638  * 2) If the OOTB packet contains an ABORT chunk, the receiver MUST
4639  *    silently discard the OOTB packet and take no further action.
4640  *
4641  * Verification Tag: No verification necessary
4642  *
4643  * Inputs
4644  * (endpoint, asoc, chunk)
4645  *
4646  * Outputs
4647  * (asoc, reply_msg, msg_up, timers, counters)
4648  *
4649  * The return value is the disposition of the chunk.
4650  */
4651 enum sctp_disposition sctp_sf_pdiscard(struct net *net,
4652                                        const struct sctp_endpoint *ep,
4653                                        const struct sctp_association *asoc,
4654                                        const union sctp_subtype type,
4655                                        void *arg, struct sctp_cmd_seq *commands)
4656 {
4657         SCTP_INC_STATS(net, SCTP_MIB_IN_PKT_DISCARDS);
4658         sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL());
4659 
4660         return SCTP_DISPOSITION_CONSUME;
4661 }
4662 
4663 
4664 /*
4665  * The other end is violating protocol.
4666  *
4667  * Section: Not specified
4668  * Verification Tag: Not specified
4669  * Inputs
4670  * (endpoint, asoc, chunk)
4671  *
4672  * Outputs
4673  * (asoc, reply_msg, msg_up, timers, counters)
4674  *
4675  * We simply tag the chunk as a violation.  The state machine will log
4676  * the violation and continue.
4677  */
4678 enum sctp_disposition sctp_sf_violation(struct net *net,
4679                                         const struct sctp_endpoint *ep,
4680                                         const struct sctp_association *asoc,
4681                                         const union sctp_subtype type,
4682                                         void *arg,
4683                                         struct sctp_cmd_seq *commands)
4684 {
4685         struct sctp_chunk *chunk = arg;
4686 
4687         if (!sctp_vtag_verify(chunk, asoc))
4688                 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands);
4689 
4690         /* Make sure that the chunk has a valid length. */
4691         if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr)))
4692                 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg,
4693                                                   commands);
4694 
4695         return SCTP_DISPOSITION_VIOLATION;
4696 }
4697 
4698 /*
4699  * Common function to handle a protocol violation.
4700  */
4701 static enum sctp_disposition sctp_sf_abort_violation(
4702                                         struct net *net,
4703                                         const struct sctp_endpoint *ep,
4704                                         const struct sctp_association *asoc,
4705                                         void *arg,
4706                                         struct sctp_cmd_seq *commands,
4707                                         const __u8 *payload,
4708                                         const size_t paylen)
4709 {
4710         struct sctp_packet *packet = NULL;
4711         struct sctp_chunk *chunk =  arg;
4712         struct sctp_chunk *abort = NULL;
4713 
4714         /* SCTP-AUTH, Section 6.3:
4715          *    It should be noted that if the receiver wants to tear
4716          *    down an association in an authenticated way only, the
4717          *    handling of malformed packets should not result in
4718          *    tearing down the association.
4719          *
4720          * This means that if we only want to abort associations
4721          * in an authenticated way (i.e AUTH+ABORT), then we
4722          * can't destroy this association just because the packet
4723          * was malformed.
4724          */
4725         if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc))
4726                 goto discard;
4727 
4728         /* Make the abort chunk. */
4729         abort = sctp_make_abort_violation(asoc, chunk, payload, paylen);
4730         if (!abort)
4731                 goto nomem;
4732 
4733         if (asoc) {
4734                 /* Treat INIT-ACK as a special case during COOKIE-WAIT. */
4735                 if (chunk->chunk_hdr->type == SCTP_CID_INIT_ACK &&
4736                     !asoc->peer.i.init_tag) {
4737                         struct sctp_initack_chunk *initack;
4738 
4739                         initack = (struct sctp_initack_chunk *)chunk->chunk_hdr;
4740                         if (!sctp_chunk_length_valid(chunk, sizeof(*initack)))
4741                                 abort->chunk_hdr->flags |= SCTP_CHUNK_FLAG_T;
4742                         else {
4743                                 unsigned int inittag;
4744 
4745                                 inittag = ntohl(initack->init_hdr.init_tag);
4746                                 sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_INITTAG,
4747                                                 SCTP_U32(inittag));
4748                         }
4749                 }
4750 
4751                 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort));
4752                 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
4753 
4754                 if (asoc->state <= SCTP_STATE_COOKIE_ECHOED) {
4755                         sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
4756                                         SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
4757                         sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
4758                                         SCTP_ERROR(ECONNREFUSED));
4759                         sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
4760                                         SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION));
4761                 } else {
4762                         sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
4763                                         SCTP_ERROR(ECONNABORTED));
4764                         sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
4765                                         SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION));
4766                         SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
4767                 }
4768         } else {
4769                 packet = sctp_ootb_pkt_new(net, asoc, chunk);
4770 
4771                 if (!packet)
4772                         goto nomem_pkt;
4773 
4774                 if (sctp_test_T_bit(abort))
4775                         packet->vtag = ntohl(chunk->sctp_hdr->vtag);
4776 
4777                 abort->skb->sk = ep->base.sk;
4778 
4779                 sctp_packet_append_chunk(packet, abort);
4780 
4781                 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
4782                         SCTP_PACKET(packet));
4783 
4784                 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
4785         }
4786 
4787         SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
4788 
4789 discard:
4790         sctp_sf_pdiscard(net, ep, asoc, SCTP_ST_CHUNK(0), arg, commands);
4791         return SCTP_DISPOSITION_ABORT;
4792 
4793 nomem_pkt:
4794         sctp_chunk_free(abort);
4795 nomem:
4796         return SCTP_DISPOSITION_NOMEM;
4797 }
4798 
4799 /*
4800  * Handle a protocol violation when the chunk length is invalid.
4801  * "Invalid" length is identified as smaller than the minimal length a
4802  * given chunk can be.  For example, a SACK chunk has invalid length
4803  * if its length is set to be smaller than the size of struct sctp_sack_chunk.
4804  *
4805  * We inform the other end by sending an ABORT with a Protocol Violation
4806  * error code.
4807  *
4808  * Section: Not specified
4809  * Verification Tag:  Nothing to do
4810  * Inputs
4811  * (endpoint, asoc, chunk)
4812  *
4813  * Outputs
4814  * (reply_msg, msg_up, counters)
4815  *
4816  * Generate an  ABORT chunk and terminate the association.
4817  */
4818 static enum sctp_disposition sctp_sf_violation_chunklen(
4819                                         struct net *net,
4820                                         const struct sctp_endpoint *ep,
4821                                         const struct sctp_association *asoc,
4822                                         const union sctp_subtype type,
4823                                         void *arg,
4824                                         struct sctp_cmd_seq *commands)
4825 {
4826         static const char err_str[] = "The following chunk had invalid length:";
4827 
4828         return sctp_sf_abort_violation(net, ep, asoc, arg, commands, err_str,
4829                                        sizeof(err_str));
4830 }
4831 
4832 /*
4833  * Handle a protocol violation when the parameter length is invalid.
4834  * If the length is smaller than the minimum length of a given parameter,
4835  * or accumulated length in multi parameters exceeds the end of the chunk,
4836  * the length is considered as invalid.
4837  */
4838 static enum sctp_disposition sctp_sf_violation_paramlen(
4839                                         struct net *net,
4840                                         const struct sctp_endpoint *ep,
4841                                         const struct sctp_association *asoc,
4842                                         const union sctp_subtype type,
4843                                         void *arg, void *ext,
4844                                         struct sctp_cmd_seq *commands)
4845 {
4846         struct sctp_paramhdr *param = ext;
4847         struct sctp_chunk *abort = NULL;
4848         struct sctp_chunk *chunk = arg;
4849 
4850         if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc))
4851                 goto discard;
4852 
4853         /* Make the abort chunk. */
4854         abort = sctp_make_violation_paramlen(asoc, chunk, param);
4855         if (!abort)
4856                 goto nomem;
4857 
4858         sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort));
4859         SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
4860 
4861         sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
4862                         SCTP_ERROR(ECONNABORTED));
4863         sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
4864                         SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION));
4865         SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
4866         SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
4867 
4868 discard:
4869         sctp_sf_pdiscard(net, ep, asoc, SCTP_ST_CHUNK(0), arg, commands);
4870         return SCTP_DISPOSITION_ABORT;
4871 nomem:
4872         return SCTP_DISPOSITION_NOMEM;
4873 }
4874 
4875 /* Handle a protocol violation when the peer trying to advance the
4876  * cumulative tsn ack to a point beyond the max tsn currently sent.
4877  *
4878  * We inform the other end by sending an ABORT with a Protocol Violation
4879  * error code.
4880  */
4881 static enum sctp_disposition sctp_sf_violation_ctsn(
4882                                         struct net *net,
4883                                         const struct sctp_endpoint *ep,
4884                                         const struct sctp_association *asoc,
4885                                         const union sctp_subtype type,
4886                                         void *arg,
4887                                         struct sctp_cmd_seq *commands)
4888 {
4889         static const char err_str[] = "The cumulative tsn ack beyond the max tsn currently sent:";
4890 
4891         return sctp_sf_abort_violation(net, ep, asoc, arg, commands, err_str,
4892                                        sizeof(err_str));
4893 }
4894 
4895 /* Handle protocol violation of an invalid chunk bundling.  For example,
4896  * when we have an association and we receive bundled INIT-ACK, or
4897  * SHUTDOWN-COMPLETE, our peer is clearly violating the "MUST NOT bundle"
4898  * statement from the specs.  Additionally, there might be an attacker
4899  * on the path and we may not want to continue this communication.
4900  */
4901 static enum sctp_disposition sctp_sf_violation_chunk(
4902                                         struct net *net,
4903                                         const struct sctp_endpoint *ep,
4904                                         const struct sctp_association *asoc,
4905                                         const union sctp_subtype type,
4906                                         void *arg,
4907                                         struct sctp_cmd_seq *commands)
4908 {
4909         static const char err_str[] = "The following chunk violates protocol:";
4910 
4911         return sctp_sf_abort_violation(net, ep, asoc, arg, commands, err_str,
4912                                        sizeof(err_str));
4913 }
4914 /***************************************************************************
4915  * These are the state functions for handling primitive (Section 10) events.
4916  ***************************************************************************/
4917 /*
4918  * sctp_sf_do_prm_asoc
4919  *
4920  * Section: 10.1 ULP-to-SCTP
4921  * B) Associate
4922  *
4923  * Format: ASSOCIATE(local SCTP instance name, destination transport addr,
4924  * outbound stream count)
4925  * -> association id [,destination transport addr list] [,outbound stream
4926  * count]
4927  *
4928  * This primitive allows the upper layer to initiate an association to a
4929  * specific peer endpoint.
4930  *
4931  * The peer endpoint shall be specified by one of the transport addresses
4932  * which defines the endpoint (see Section 1.4).  If the local SCTP
4933  * instance has not been initialized, the ASSOCIATE is considered an
4934  * error.
4935  * [This is not relevant for the kernel implementation since we do all
4936  * initialization at boot time.  It we hadn't initialized we wouldn't
4937  * get anywhere near this code.]
4938  *
4939  * An association id, which is a local handle to the SCTP association,
4940  * will be returned on successful establishment of the association. If
4941  * SCTP is not able to open an SCTP association with the peer endpoint,
4942  * an error is returned.
4943  * [In the kernel implementation, the struct sctp_association needs to
4944  * be created BEFORE causing this primitive to run.]
4945  *
4946  * Other association parameters may be returned, including the
4947  * complete destination transport addresses of the peer as well as the
4948  * outbound stream count of the local endpoint. One of the transport
4949  * address from the returned destination addresses will be selected by
4950  * the local endpoint as default primary path for sending SCTP packets
4951  * to this peer.  The returned "destination transport addr list" can
4952  * be used by the ULP to change the default primary path or to force
4953  * sending a packet to a specific transport address.  [All of this
4954  * stuff happens when the INIT ACK arrives.  This is a NON-BLOCKING
4955  * function.]
4956  *
4957  * Mandatory attributes:
4958  *
4959  * o local SCTP instance name - obtained from the INITIALIZE operation.
4960  *   [This is the argument asoc.]
4961  * o destination transport addr - specified as one of the transport
4962  * addresses of the peer endpoint with which the association is to be
4963  * established.
4964  *  [This is asoc->peer.active_path.]
4965  * o outbound stream count - the number of outbound streams the ULP
4966  * would like to open towards this peer endpoint.
4967  * [BUG: This is not currently implemented.]
4968  * Optional attributes:
4969  *
4970  * None.
4971  *
4972  * The return value is a disposition.
4973  */
4974 enum sctp_disposition sctp_sf_do_prm_asoc(struct net *net,
4975                                           const struct sctp_endpoint *ep,
4976                                           const struct sctp_association *asoc,
4977                                           const union sctp_subtype type,
4978                                           void *arg,
4979                                           struct sctp_cmd_seq *commands)
4980 {
4981         struct sctp_association *my_asoc;
4982         struct sctp_chunk *repl;
4983 
4984         /* The comment below says that we enter COOKIE-WAIT AFTER
4985          * sending the INIT, but that doesn't actually work in our
4986          * implementation...
4987          */
4988         sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
4989                         SCTP_STATE(SCTP_STATE_COOKIE_WAIT));
4990 
4991         /* RFC 2960 5.1 Normal Establishment of an Association
4992          *
4993          * A) "A" first sends an INIT chunk to "Z".  In the INIT, "A"
4994          * must provide its Verification Tag (Tag_A) in the Initiate
4995          * Tag field.  Tag_A SHOULD be a random number in the range of
4996          * 1 to 4294967295 (see 5.3.1 for Tag value selection). ...
4997          */
4998 
4999         repl = sctp_make_init(asoc, &asoc->base.bind_addr, GFP_ATOMIC, 0);
5000         if (!repl)
5001                 goto nomem;
5002 
5003         /* Choose transport for INIT. */
5004         sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT,
5005                         SCTP_CHUNK(repl));
5006 
5007         /* Cast away the const modifier, as we want to just
5008          * rerun it through as a sideffect.
5009          */
5010         my_asoc = (struct sctp_association *)asoc;
5011         sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(my_asoc));
5012 
5013         /* After sending the INIT, "A" starts the T1-init timer and
5014          * enters the COOKIE-WAIT state.
5015          */
5016         sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
5017                         SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
5018         sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
5019         return SCTP_DISPOSITION_CONSUME;
5020 
5021 nomem:
5022         return SCTP_DISPOSITION_NOMEM;
5023 }
5024 
5025 /*
5026  * Process the SEND primitive.
5027  *
5028  * Section: 10.1 ULP-to-SCTP
5029  * E) Send
5030  *
5031  * Format: SEND(association id, buffer address, byte count [,context]
5032  *         [,stream id] [,life time] [,destination transport address]
5033  *         [,unorder flag] [,no-bundle flag] [,payload protocol-id] )
5034  * -> result
5035  *
5036  * This is the main method to send user data via SCTP.
5037  *
5038  * Mandatory attributes:
5039  *
5040  *  o association id - local handle to the SCTP association
5041  *
5042  *  o buffer address - the location where the user message to be
5043  *    transmitted is stored;
5044  *
5045  *  o byte count - The size of the user data in number of bytes;
5046  *
5047  * Optional attributes:
5048  *
5049  *  o context - an optional 32 bit integer that will be carried in the
5050  *    sending failure notification to the ULP if the transportation of
5051  *    this User Message fails.
5052  *
5053  *  o stream id - to indicate which stream to send the data on. If not
5054  *    specified, stream 0 will be used.
5055  *
5056  *  o life time - specifies the life time of the user data. The user data
5057  *    will not be sent by SCTP after the life time expires. This
5058  *    parameter can be used to avoid efforts to transmit stale
5059  *    user messages. SCTP notifies the ULP if the data cannot be
5060  *    initiated to transport (i.e. sent to the destination via SCTP's
5061  *    send primitive) within the life time variable. However, the
5062  *    user data will be transmitted if SCTP has attempted to transmit a
5063  *    chunk before the life time expired.
5064  *
5065  *  o destination transport address - specified as one of the destination
5066  *    transport addresses of the peer endpoint to which this packet
5067  *    should be sent. Whenever possible, SCTP should use this destination
5068  *    transport address for sending the packets, instead of the current
5069  *    primary path.
5070  *
5071  *  o unorder flag - this flag, if present, indicates that the user
5072  *    would like the data delivered in an unordered fashion to the peer
5073  *    (i.e., the U flag is set to 1 on all DATA chunks carrying this
5074  *    message).
5075  *
5076  *  o no-bundle flag - instructs SCTP not to bundle this user data with
5077  *    other outbound DATA chunks. SCTP MAY still bundle even when
5078  *    this flag is present, when faced with network congestion.
5079  *
5080  *  o payload protocol-id - A 32 bit unsigned integer that is to be
5081  *    passed to the peer indicating the type of payload protocol data
5082  *    being transmitted. This value is passed as opaque data by SCTP.
5083  *
5084  * The return value is the disposition.
5085  */
5086 enum sctp_disposition sctp_sf_do_prm_send(struct net *net,
5087                                           const struct sctp_endpoint *ep,
5088                                           const struct sctp_association *asoc,
5089                                           const union sctp_subtype type,
5090                                           void *arg,
5091                                           struct sctp_cmd_seq *commands)
5092 {
5093         struct sctp_datamsg *msg = arg;
5094 
5095         sctp_add_cmd_sf(commands, SCTP_CMD_SEND_MSG, SCTP_DATAMSG(msg));
5096         return SCTP_DISPOSITION_CONSUME;
5097 }
5098 
5099 /*
5100  * Process the SHUTDOWN primitive.
5101  *
5102  * Section: 10.1:
5103  * C) Shutdown
5104  *
5105  * Format: SHUTDOWN(association id)
5106  * -> result
5107  *
5108  * Gracefully closes an association. Any locally queued user data
5109  * will be delivered to the peer. The association will be terminated only
5110  * after the peer acknowledges all the SCTP packets sent.  A success code
5111  * will be returned on successful termination of the association. If
5112  * attempting to terminate the association results in a failure, an error
5113  * code shall be returned.
5114  *
5115  * Mandatory attributes:
5116  *
5117  *  o association id - local handle to the SCTP association
5118  *
5119  * Optional attributes:
5120  *
5121  * None.
5122  *
5123  * The return value is the disposition.
5124  */
5125 enum sctp_disposition sctp_sf_do_9_2_prm_shutdown(
5126                                         struct net *net,
5127                                         const struct sctp_endpoint *ep,
5128                                         const struct sctp_association *asoc,
5129                                         const union sctp_subtype type,
5130                                         void *arg,
5131                                         struct sctp_cmd_seq *commands)
5132 {
5133         enum sctp_disposition disposition;
5134 
5135         /* From 9.2 Shutdown of an Association
5136          * Upon receipt of the SHUTDOWN primitive from its upper
5137          * layer, the endpoint enters SHUTDOWN-PENDING state and
5138          * remains there until all outstanding data has been
5139          * acknowledged by its peer. The endpoint accepts no new data
5140          * from its upper layer, but retransmits data to the far end
5141          * if necessary to fill gaps.
5142          */
5143         sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
5144                         SCTP_STATE(SCTP_STATE_SHUTDOWN_PENDING));
5145 
5146         disposition = SCTP_DISPOSITION_CONSUME;
5147         if (sctp_outq_is_empty(&asoc->outqueue)) {
5148                 disposition = sctp_sf_do_9_2_start_shutdown(net, ep, asoc, type,
5149                                                             arg, commands);
5150         }
5151 
5152         return disposition;
5153 }
5154 
5155 /*
5156  * Process the ABORT primitive.
5157  *
5158  * Section: 10.1:
5159  * C) Abort
5160  *
5161  * Format: Abort(association id [, cause code])
5162  * -> result
5163  *
5164  * Ungracefully closes an association. Any locally queued user data
5165  * will be discarded and an ABORT chunk is sent to the peer.  A success code
5166  * will be returned on successful abortion of the association. If
5167  * attempting to abort the association results in a failure, an error
5168  * code shall be returned.
5169  *
5170  * Mandatory attributes:
5171  *
5172  *  o association id - local handle to the SCTP association
5173  *
5174  * Optional attributes:
5175  *
5176  *  o cause code - reason of the abort to be passed to the peer
5177  *
5178  * None.
5179  *
5180  * The return value is the disposition.
5181  */
5182 enum sctp_disposition sctp_sf_do_9_1_prm_abort(
5183                                         struct net *net,
5184                                         const struct sctp_endpoint *ep,
5185                                         const struct sctp_association *asoc,
5186                                         const union sctp_subtype type,
5187                                         void *arg,
5188                                         struct sctp_cmd_seq *commands)
5189 {
5190         /* From 9.1 Abort of an Association
5191          * Upon receipt of the ABORT primitive from its upper
5192          * layer, the endpoint enters CLOSED state and
5193          * discard all outstanding data has been
5194          * acknowledged by its peer. The endpoint accepts no new data
5195          * from its upper layer, but retransmits data to the far end
5196          * if necessary to fill gaps.
5197          */
5198         struct sctp_chunk *abort = arg;
5199 
5200         if (abort)
5201                 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort));
5202 
5203         /* Even if we can't send the ABORT due to low memory delete the
5204          * TCB.  This is a departure from our typical NOMEM handling.
5205          */
5206 
5207         sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
5208                         SCTP_ERROR(ECONNABORTED));
5209         /* Delete the established association. */
5210         sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
5211                         SCTP_PERR(SCTP_ERROR_USER_ABORT));
5212 
5213         SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
5214         SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
5215 
5216         return SCTP_DISPOSITION_ABORT;
5217 }
5218 
5219 /* We tried an illegal operation on an association which is closed.  */
5220 enum sctp_disposition sctp_sf_error_closed(struct net *net,
5221                                            const struct sctp_endpoint *ep,
5222                                            const struct sctp_association *asoc,
5223                                            const union sctp_subtype type,
5224                                            void *arg,
5225                                            struct sctp_cmd_seq *commands)
5226 {
5227         sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_ERROR, SCTP_ERROR(-EINVAL));
5228         return SCTP_DISPOSITION_CONSUME;
5229 }
5230 
5231 /* We tried an illegal operation on an association which is shutting
5232  * down.
5233  */
5234 enum sctp_disposition sctp_sf_error_shutdown(
5235                                         struct net *net,
5236                                         const struct sctp_endpoint *ep,
5237                                         const struct sctp_association *asoc,
5238                                         const union sctp_subtype type,
5239                                         void *arg,
5240                                         struct sctp_cmd_seq *commands)
5241 {
5242         sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_ERROR,
5243                         SCTP_ERROR(-ESHUTDOWN));
5244         return SCTP_DISPOSITION_CONSUME;
5245 }
5246 
5247 /*
5248  * sctp_cookie_wait_prm_shutdown
5249  *
5250  * Section: 4 Note: 2
5251  * Verification Tag:
5252  * Inputs
5253  * (endpoint, asoc)
5254  *
5255  * The RFC does not explicitly address this issue, but is the route through the
5256  * state table when someone issues a shutdown while in COOKIE_WAIT state.
5257  *
5258  * Outputs
5259  * (timers)
5260  */
5261 enum sctp_disposition sctp_sf_cookie_wait_prm_shutdown(
5262                                         struct net *net,
5263                                         const struct sctp_endpoint *ep,
5264                                         const struct sctp_association *asoc,
5265                                         const union sctp_subtype type,
5266                                         void *arg,
5267                                         struct sctp_cmd_seq *commands)
5268 {
5269         sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
5270                         SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
5271 
5272         sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
5273                         SCTP_STATE(SCTP_STATE_CLOSED));
5274 
5275         SCTP_INC_STATS(net, SCTP_MIB_SHUTDOWNS);
5276 
5277         sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL());
5278 
5279         return SCTP_DISPOSITION_DELETE_TCB;
5280 }
5281 
5282 /*
5283  * sctp_cookie_echoed_prm_shutdown
5284  *
5285  * Section: 4 Note: 2
5286  * Verification Tag:
5287  * Inputs
5288  * (endpoint, asoc)
5289  *
5290  * The RFC does not explicitly address this issue, but is the route through the
5291  * state table when someone issues a shutdown while in COOKIE_ECHOED state.
5292  *
5293  * Outputs
5294  * (timers)
5295  */
5296 enum sctp_disposition sctp_sf_cookie_echoed_prm_shutdown(
5297                                         struct net *net,
5298                                         const struct sctp_endpoint *ep,
5299                                         const struct sctp_association *asoc,
5300                                         const union sctp_subtype type,
5301                                         void *arg,
5302                                         struct sctp_cmd_seq *commands)
5303 {
5304         /* There is a single T1 timer, so we should be able to use
5305          * common function with the COOKIE-WAIT state.
5306          */
5307         return sctp_sf_cookie_wait_prm_shutdown(net, ep, asoc, type, arg, commands);
5308 }
5309 
5310 /*
5311  * sctp_sf_cookie_wait_prm_abort
5312  *
5313  * Section: 4 Note: 2
5314  * Verification Tag:
5315  * Inputs
5316  * (endpoint, asoc)
5317  *
5318  * The RFC does not explicitly address this issue, but is the route through the
5319  * state table when someone issues an abort while in COOKIE_WAIT state.
5320  *
5321  * Outputs
5322  * (timers)
5323  */
5324 enum sctp_disposition sctp_sf_cookie_wait_prm_abort(
5325                                         struct net *net,
5326                                         const struct sctp_endpoint *ep,
5327                                         const struct sctp_association *asoc,
5328                                         const union sctp_subtype type,
5329                                         void *arg,
5330                                         struct sctp_cmd_seq *commands)
5331 {
5332         struct sctp_chunk *abort = arg;
5333 
5334         /* Stop T1-init timer */
5335         sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
5336                         SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
5337 
5338         if (abort)
5339                 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort));
5340 
5341         sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
5342                         SCTP_STATE(SCTP_STATE_CLOSED));
5343 
5344         SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
5345 
5346         /* Even if we can't send the ABORT due to low memory delete the
5347          * TCB.  This is a departure from our typical NOMEM handling.
5348          */
5349 
5350         sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
5351                         SCTP_ERROR(ECONNREFUSED));
5352         /* Delete the established association. */
5353         sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
5354                         SCTP_PERR(SCTP_ERROR_USER_ABORT));
5355 
5356         return SCTP_DISPOSITION_ABORT;
5357 }
5358 
5359 /*
5360  * sctp_sf_cookie_echoed_prm_abort
5361  *
5362  * Section: 4 Note: 3
5363  * Verification Tag:
5364  * Inputs
5365  * (endpoint, asoc)
5366  *
5367  * The RFC does not explcitly address this issue, but is the route through the
5368  * state table when someone issues an abort while in COOKIE_ECHOED state.
5369  *
5370  * Outputs
5371  * (timers)
5372  */
5373 enum sctp_disposition sctp_sf_cookie_echoed_prm_abort(
5374                                         struct net *net,
5375                                         const struct sctp_endpoint *ep,
5376                                         const struct sctp_association *asoc,
5377                                         const union sctp_subtype type,
5378                                         void *arg,
5379                                         struct sctp_cmd_seq *commands)
5380 {
5381         /* There is a single T1 timer, so we should be able to use
5382          * common function with the COOKIE-WAIT state.
5383          */
5384         return sctp_sf_cookie_wait_prm_abort(net, ep, asoc, type, arg, commands);
5385 }
5386 
5387 /*
5388  * sctp_sf_shutdown_pending_prm_abort
5389  *
5390  * Inputs
5391  * (endpoint, asoc)
5392  *
5393  * The RFC does not explicitly address this issue, but is the route through the
5394  * state table when someone issues an abort while in SHUTDOWN-PENDING state.
5395  *
5396  * Outputs
5397  * (timers)
5398  */
5399 enum sctp_disposition sctp_sf_shutdown_pending_prm_abort(
5400                                         struct net *net,
5401                                         const struct sctp_endpoint *ep,
5402                                         const struct sctp_association *asoc,
5403                                         const union sctp_subtype type,
5404                                         void *arg,
5405                                         struct sctp_cmd_seq *commands)
5406 {
5407         /* Stop the T5-shutdown guard timer.  */
5408         sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
5409                         SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
5410 
5411         return sctp_sf_do_9_1_prm_abort(net, ep, asoc, type, arg, commands);
5412 }
5413 
5414 /*
5415  * sctp_sf_shutdown_sent_prm_abort
5416  *
5417  * Inputs
5418  * (endpoint, asoc)
5419  *
5420  * The RFC does not explicitly address this issue, but is the route through the
5421  * state table when someone issues an abort while in SHUTDOWN-SENT state.
5422  *
5423  * Outputs
5424  * (timers)
5425  */
5426 enum sctp_disposition sctp_sf_shutdown_sent_prm_abort(
5427                                         struct net *net,
5428                                         const struct sctp_endpoint *ep,
5429                                         const struct sctp_association *asoc,
5430                                         const union sctp_subtype type,
5431                                         void *arg,
5432                                         struct sctp_cmd_seq *commands)
5433 {
5434         /* Stop the T2-shutdown timer.  */
5435         sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
5436                         SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
5437 
5438         /* Stop the T5-shutdown guard timer.  */
5439         sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
5440                         SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
5441 
5442         return sctp_sf_do_9_1_prm_abort(net, ep, asoc, type, arg, commands);
5443 }
5444 
5445 /*
5446  * sctp_sf_cookie_echoed_prm_abort
5447  *
5448  * Inputs
5449  * (endpoint, asoc)
5450  *
5451  * The RFC does not explcitly address this issue, but is the route through the
5452  * state table when someone issues an abort while in COOKIE_ECHOED state.
5453  *
5454  * Outputs
5455  * (timers)
5456  */
5457 enum sctp_disposition sctp_sf_shutdown_ack_sent_prm_abort(
5458                                         struct net *net,
5459                                         const struct sctp_endpoint *ep,
5460                                         const struct sctp_association *asoc,
5461                                         const union sctp_subtype type,
5462                                         void *arg,
5463                                         struct sctp_cmd_seq *commands)
5464 {
5465         /* The same T2 timer, so we should be able to use
5466          * common function with the SHUTDOWN-SENT state.
5467          */
5468         return sctp_sf_shutdown_sent_prm_abort(net, ep, asoc, type, arg, commands);
5469 }
5470 
5471 /*
5472  * Process the REQUESTHEARTBEAT primitive
5473  *
5474  * 10.1 ULP-to-SCTP
5475  * J) Request Heartbeat
5476  *
5477  * Format: REQUESTHEARTBEAT(association id, destination transport address)
5478  *
5479  * -> result
5480  *
5481  * Instructs the local endpoint to perform a HeartBeat on the specified
5482  * destination transport address of the given association. The returned
5483  * result should indicate whether the transmission of the HEARTBEAT
5484  * chunk to the destination address is successful.
5485  *
5486  * Mandatory attributes:
5487  *
5488  * o association id - local handle to the SCTP association
5489  *
5490  * o destination transport address - the transport address of the
5491  *   association on which a heartbeat should be issued.
5492  */
5493 enum sctp_disposition sctp_sf_do_prm_requestheartbeat(
5494                                         struct net *net,
5495                                         const struct sctp_endpoint *ep,
5496                                         const struct sctp_association *asoc,
5497                                         const union sctp_subtype type,
5498                                         void *arg,
5499                                         struct sctp_cmd_seq *commands)
5500 {
5501         if (SCTP_DISPOSITION_NOMEM == sctp_sf_heartbeat(ep, asoc, type,
5502                                       (struct sctp_transport *)arg, commands))
5503                 return SCTP_DISPOSITION_NOMEM;
5504 
5505         /*
5506          * RFC 2960 (bis), section 8.3
5507          *
5508          *    D) Request an on-demand HEARTBEAT on a specific destination
5509          *    transport address of a given association.
5510          *
5511          *    The endpoint should increment the respective error  counter of
5512          *    the destination transport address each time a HEARTBEAT is sent
5513          *    to that address and not acknowledged within one RTO.
5514          *
5515          */
5516         sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_HB_SENT,
5517                         SCTP_TRANSPORT(arg));
5518         return SCTP_DISPOSITION_CONSUME;
5519 }
5520 
5521 /*
5522  * ADDIP Section 4.1 ASCONF Chunk Procedures
5523  * When an endpoint has an ASCONF signaled change to be sent to the
5524  * remote endpoint it should do A1 to A9
5525  */
5526 enum sctp_disposition sctp_sf_do_prm_asconf(struct net *net,
5527                                             const struct sctp_endpoint *ep,
5528                                             const struct sctp_association *asoc,
5529                                             const union sctp_subtype type,
5530                                             void *arg,
5531                                             struct sctp_cmd_seq *commands)
5532 {
5533         struct sctp_chunk *chunk = arg;
5534 
5535         sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk));
5536         sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
5537                         SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
5538         sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(chunk));
5539         return SCTP_DISPOSITION_CONSUME;
5540 }
5541 
5542 /* RE-CONFIG Section 5.1 RECONF Chunk Procedures */
5543 enum sctp_disposition sctp_sf_do_prm_reconf(struct net *net,
5544                                             const struct sctp_endpoint *ep,
5545                                             const struct sctp_association *asoc,
5546                                             const union sctp_subtype type,
5547                                             void *arg,
5548                                             struct sctp_cmd_seq *commands)
5549 {
5550         struct sctp_chunk *chunk = arg;
5551 
5552         sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(chunk));
5553         return SCTP_DISPOSITION_CONSUME;
5554 }
5555 
5556 /*
5557  * Ignore the primitive event
5558  *
5559  * The return value is the disposition of the primitive.
5560  */
5561 enum sctp_disposition sctp_sf_ignore_primitive(
5562                                         struct net *net,
5563                                         const struct sctp_endpoint *ep,
5564                                         const struct sctp_association *asoc,
5565                                         const union sctp_subtype type,
5566                                         void *arg,
5567                                         struct sctp_cmd_seq *commands)
5568 {
5569         pr_debug("%s: primitive type:%d is ignored\n", __func__,
5570                  type.primitive);
5571 
5572         return SCTP_DISPOSITION_DISCARD;
5573 }
5574 
5575 /***************************************************************************
5576  * These are the state functions for the OTHER events.
5577  ***************************************************************************/
5578 
5579 /*
5580  * When the SCTP stack has no more user data to send or retransmit, this
5581  * notification is given to the user. Also, at the time when a user app
5582  * subscribes to this event, if there is no data to be sent or
5583  * retransmit, the stack will immediately send up this notification.
5584  */
5585 enum sctp_disposition sctp_sf_do_no_pending_tsn(
5586                                         struct net *net,
5587                                         const struct sctp_endpoint *ep,
5588                                         const struct sctp_association *asoc,
5589                                         const union sctp_subtype type,
5590                                         void *arg,
5591                                         struct sctp_cmd_seq *commands)
5592 {
5593         struct sctp_ulpevent *event;
5594 
5595         event = sctp_ulpevent_make_sender_dry_event(asoc, GFP_ATOMIC);
5596         if (!event)
5597                 return SCTP_DISPOSITION_NOMEM;
5598 
5599         sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(event));
5600 
5601         return SCTP_DISPOSITION_CONSUME;
5602 }
5603 
5604 /*
5605  * Start the shutdown negotiation.
5606  *
5607  * From Section 9.2:
5608  * Once all its outstanding data has been acknowledged, the endpoint
5609  * shall send a SHUTDOWN chunk to its peer including in the Cumulative
5610  * TSN Ack field the last sequential TSN it has received from the peer.
5611  * It shall then start the T2-shutdown timer and enter the SHUTDOWN-SENT
5612  * state. If the timer expires, the endpoint must re-send the SHUTDOWN
5613  * with the updated last sequential TSN received from its peer.
5614  *
5615  * The return value is the disposition.
5616  */
5617 enum sctp_disposition sctp_sf_do_9_2_start_shutdown(
5618                                         struct net *net,
5619                                         const struct sctp_endpoint *ep,
5620                                         const struct sctp_association *asoc,
5621                                         const union sctp_subtype type,
5622                                         void *arg,
5623                                         struct sctp_cmd_seq *commands)
5624 {
5625         struct sctp_chunk *reply;
5626 
5627         /* Once all its outstanding data has been acknowledged, the
5628          * endpoint shall send a SHUTDOWN chunk to its peer including
5629          * in the Cumulative TSN Ack field the last sequential TSN it
5630          * has received from the peer.
5631          */
5632         reply = sctp_make_shutdown(asoc, arg);
5633         if (!reply)
5634                 goto nomem;
5635 
5636         /* Set the transport for the SHUTDOWN chunk and the timeout for the
5637          * T2-shutdown timer.
5638          */
5639         sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply));
5640 
5641         /* It shall then start the T2-shutdown timer */
5642         sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START,
5643                         SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
5644 
5645         /* RFC 4960 Section 9.2
5646          * The sender of the SHUTDOWN MAY also start an overall guard timer
5647          * 'T5-shutdown-guard' to bound the overall time for shutdown sequence.
5648          */
5649         sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
5650                         SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
5651 
5652         if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE])
5653                 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
5654                                 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
5655 
5656         /* and enter the SHUTDOWN-SENT state.  */
5657         sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
5658                         SCTP_STATE(SCTP_STATE_SHUTDOWN_SENT));
5659 
5660         /* sctp-implguide 2.10 Issues with Heartbeating and failover
5661          *
5662          * HEARTBEAT ... is discontinued after sending either SHUTDOWN
5663          * or SHUTDOWN-ACK.
5664          */
5665         sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL());
5666 
5667         sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
5668 
5669         return SCTP_DISPOSITION_CONSUME;
5670 
5671 nomem:
5672         return SCTP_DISPOSITION_NOMEM;
5673 }
5674 
5675 /*
5676  * Generate a SHUTDOWN ACK now that everything is SACK'd.
5677  *
5678  * From Section 9.2:
5679  *
5680  * If it has no more outstanding DATA chunks, the SHUTDOWN receiver
5681  * shall send a SHUTDOWN ACK and start a T2-shutdown timer of its own,
5682  * entering the SHUTDOWN-ACK-SENT state. If the timer expires, the
5683  * endpoint must re-send the SHUTDOWN ACK.
5684  *
5685  * The return value is the disposition.
5686  */
5687 enum sctp_disposition sctp_sf_do_9_2_shutdown_ack(
5688                                         struct net *net,
5689                                         const struct sctp_endpoint *ep,
5690                                         const struct sctp_association *asoc,
5691                                         const union sctp_subtype type,
5692                                         void *arg,
5693                                         struct sctp_cmd_seq *commands)
5694 {
5695         struct sctp_chunk *chunk = arg;
5696         struct sctp_chunk *reply;
5697 
5698         /* There are 2 ways of getting here:
5699          *    1) called in response to a SHUTDOWN chunk
5700          *    2) called when SCTP_EVENT_NO_PENDING_TSN event is issued.
5701          *
5702          * For the case (2), the arg parameter is set to NULL.  We need
5703          * to check that we have a chunk before accessing it's fields.
5704          */
5705         if (chunk) {
5706                 if (!sctp_vtag_verify(chunk, asoc))
5707                         return sctp_sf_pdiscard(net, ep, asoc, type, arg,
5708                                                 commands);
5709 
5710                 /* Make sure that the SHUTDOWN chunk has a valid length. */
5711                 if (!sctp_chunk_length_valid(
5712                                 chunk, sizeof(struct sctp_shutdown_chunk)))
5713                         return sctp_sf_violation_chunklen(net, ep, asoc, type,
5714                                                           arg, commands);
5715         }
5716 
5717         /* If it has no more outstanding DATA chunks, the SHUTDOWN receiver
5718          * shall send a SHUTDOWN ACK ...
5719          */
5720         reply = sctp_make_shutdown_ack(asoc, chunk);
5721         if (!reply)
5722                 goto nomem;
5723 
5724         /* Set the transport for the SHUTDOWN ACK chunk and the timeout for
5725          * the T2-shutdown timer.
5726          */
5727         sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply));
5728 
5729         /* and start/restart a T2-shutdown timer of its own, */
5730         sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
5731                         SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
5732 
5733         if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE])
5734                 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
5735                                 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE));
5736 
5737         /* Enter the SHUTDOWN-ACK-SENT state.  */
5738         sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
5739                         SCTP_STATE(SCTP_STATE_SHUTDOWN_ACK_SENT));
5740 
5741         /* sctp-implguide 2.10 Issues with Heartbeating and failover
5742          *
5743          * HEARTBEAT ... is discontinued after sending either SHUTDOWN
5744          * or SHUTDOWN-ACK.
5745          */
5746         sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL());
5747 
5748         sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
5749 
5750         return SCTP_DISPOSITION_CONSUME;
5751 
5752 nomem:
5753         return SCTP_DISPOSITION_NOMEM;
5754 }
5755 
5756 /*
5757  * Ignore the event defined as other
5758  *
5759  * The return value is the disposition of the event.
5760  */
5761 enum sctp_disposition sctp_sf_ignore_other(struct net *net,
5762                                            const struct sctp_endpoint *ep,
5763                                            const struct sctp_association *asoc,
5764                                            const union sctp_subtype type,
5765                                            void *arg,
5766                                            struct sctp_cmd_seq *commands)
5767 {
5768         pr_debug("%s: the event other type:%d is ignored\n",
5769                  __func__, type.other);
5770 
5771         return SCTP_DISPOSITION_DISCARD;
5772 }
5773 
5774 /************************************************************
5775  * These are the state functions for handling timeout events.
5776  ************************************************************/
5777 
5778 /*
5779  * RTX Timeout
5780  *
5781  * Section: 6.3.3 Handle T3-rtx Expiration
5782  *
5783  * Whenever the retransmission timer T3-rtx expires for a destination
5784  * address, do the following:
5785  * [See below]
5786  *
5787  * The return value is the disposition of the chunk.
5788  */
5789 enum sctp_disposition sctp_sf_do_6_3_3_rtx(struct net *net,
5790                                            const struct sctp_endpoint *ep,
5791                                            const struct sctp_association *asoc,
5792                                            const union sctp_subtype type,
5793                                            void *arg,
5794                                            struct sctp_cmd_seq *commands)
5795 {
5796         struct sctp_transport *transport = arg;
5797 
5798         SCTP_INC_STATS(net, SCTP_MIB_T3_RTX_EXPIREDS);
5799 
5800         if (asoc->overall_error_count >= asoc->max_retrans) {
5801                 if (asoc->peer.zero_window_announced &&
5802                     asoc->state == SCTP_STATE_SHUTDOWN_PENDING) {
5803                         /*
5804                          * We are here likely because the receiver had its rwnd
5805                          * closed for a while and we have not been able to
5806                          * transmit the locally queued data within the maximum
5807                          * retransmission attempts limit.  Start the T5
5808                          * shutdown guard timer to give the receiver one last
5809                          * chance and some additional time to recover before
5810                          * aborting.
5811                          */
5812                         sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START_ONCE,
5813                                 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD));
5814                 } else {
5815                         sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
5816                                         SCTP_ERROR(ETIMEDOUT));
5817                         /* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */
5818                         sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
5819                                         SCTP_PERR(SCTP_ERROR_NO_ERROR));
5820                         SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
5821                         SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
5822                         return SCTP_DISPOSITION_DELETE_TCB;
5823                 }
5824         }
5825 
5826         /* E1) For the destination address for which the timer
5827          * expires, adjust its ssthresh with rules defined in Section
5828          * 7.2.3 and set the cwnd <- MTU.
5829          */
5830 
5831         /* E2) For the destination address for which the timer
5832          * expires, set RTO <- RTO * 2 ("back off the timer").  The
5833          * maximum value discussed in rule C7 above (RTO.max) may be
5834          * used to provide an upper bound to this doubling operation.
5835          */
5836 
5837         /* E3) Determine how many of the earliest (i.e., lowest TSN)
5838          * outstanding DATA chunks for the address for which the
5839          * T3-rtx has expired will fit into a single packet, subject
5840          * to the MTU constraint for the path corresponding to the
5841          * destination transport address to which the retransmission
5842          * is being sent (this may be different from the address for
5843          * which the timer expires [see Section 6.4]).  Call this
5844          * value K. Bundle and retransmit those K DATA chunks in a
5845          * single packet to the destination endpoint.
5846          *
5847          * Note: Any DATA chunks that were sent to the address for
5848          * which the T3-rtx timer expired but did not fit in one MTU
5849          * (rule E3 above), should be marked for retransmission and
5850          * sent as soon as cwnd allows (normally when a SACK arrives).
5851          */
5852 
5853         /* Do some failure management (Section 8.2). */
5854         sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, SCTP_TRANSPORT(transport));
5855 
5856         /* NB: Rules E4 and F1 are implicit in R1.  */
5857         sctp_add_cmd_sf(commands, SCTP_CMD_RETRAN, SCTP_TRANSPORT(transport));
5858 
5859         return SCTP_DISPOSITION_CONSUME;
5860 }
5861 
5862 /*
5863  * Generate delayed SACK on timeout
5864  *
5865  * Section: 6.2  Acknowledgement on Reception of DATA Chunks
5866  *
5867  * The guidelines on delayed acknowledgement algorithm specified in
5868  * Section 4.2 of [RFC2581] SHOULD be followed.  Specifically, an
5869  * acknowledgement SHOULD be generated for at least every second packet
5870  * (not every second DATA chunk) received, and SHOULD be generated
5871  * within 200 ms of the arrival of any unacknowledged DATA chunk.  In
5872  * some situations it may be beneficial for an SCTP transmitter to be
5873  * more conservative than the algorithms detailed in this document
5874  * allow. However, an SCTP transmitter MUST NOT be more aggressive than
5875  * the following algorithms allow.
5876  */
5877 enum sctp_disposition sctp_sf_do_6_2_sack(struct net *net,
5878                                           const struct sctp_endpoint *ep,
5879                                           const struct sctp_association *asoc,
5880                                           const union sctp_subtype type,
5881                                           void *arg,
5882                                           struct sctp_cmd_seq *commands)
5883 {
5884         SCTP_INC_STATS(net, SCTP_MIB_DELAY_SACK_EXPIREDS);
5885         sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE());
5886         return SCTP_DISPOSITION_CONSUME;
5887 }
5888 
5889 /*
5890  * sctp_sf_t1_init_timer_expire
5891  *
5892  * Section: 4 Note: 2
5893  * Verification Tag:
5894  * Inputs
5895  * (endpoint, asoc)
5896  *
5897  *  RFC 2960 Section 4 Notes
5898  *  2) If the T1-init timer expires, the endpoint MUST retransmit INIT
5899  *     and re-start the T1-init timer without changing state.  This MUST
5900  *     be repeated up to 'Max.Init.Retransmits' times.  After that, the
5901  *     endpoint MUST abort the initialization process and report the
5902  *     error to SCTP user.
5903  *
5904  * Outputs
5905  * (timers, events)
5906  *
5907  */
5908 enum sctp_disposition sctp_sf_t1_init_timer_expire(
5909                                         struct net *net,
5910                                         const struct sctp_endpoint *ep,
5911                                         const struct sctp_association *asoc,
5912                                         const union sctp_subtype type,
5913                                         void *arg,
5914                                         struct sctp_cmd_seq *commands)
5915 {
5916         int attempts = asoc->init_err_counter + 1;
5917         struct sctp_chunk *repl = NULL;
5918         struct sctp_bind_addr *bp;
5919 
5920         pr_debug("%s: timer T1 expired (INIT)\n", __func__);
5921 
5922         SCTP_INC_STATS(net, SCTP_MIB_T1_INIT_EXPIREDS);
5923 
5924         if (attempts <= asoc->max_init_attempts) {
5925                 bp = (struct sctp_bind_addr *) &asoc->base.bind_addr;
5926                 repl = sctp_make_init(asoc, bp, GFP_ATOMIC, 0);
5927                 if (!repl)
5928                         return SCTP_DISPOSITION_NOMEM;
5929 
5930                 /* Choose transport for INIT. */
5931                 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT,
5932                                 SCTP_CHUNK(repl));
5933 
5934                 /* Issue a sideeffect to do the needed accounting. */
5935                 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_RESTART,
5936                                 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT));
5937 
5938                 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
5939         } else {
5940                 pr_debug("%s: giving up on INIT, attempts:%d "
5941                          "max_init_attempts:%d\n", __func__, attempts,
5942                          asoc->max_init_attempts);
5943 
5944                 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
5945                                 SCTP_ERROR(ETIMEDOUT));
5946                 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
5947                                 SCTP_PERR(SCTP_ERROR_NO_ERROR));
5948                 return SCTP_DISPOSITION_DELETE_TCB;
5949         }
5950 
5951         return SCTP_DISPOSITION_CONSUME;
5952 }
5953 
5954 /*
5955  * sctp_sf_t1_cookie_timer_expire
5956  *
5957  * Section: 4 Note: 2
5958  * Verification Tag:
5959  * Inputs
5960  * (endpoint, asoc)
5961  *
5962  *  RFC 2960 Section 4 Notes
5963  *  3) If the T1-cookie timer expires, the endpoint MUST retransmit
5964  *     COOKIE ECHO and re-start the T1-cookie timer without changing
5965  *     state.  This MUST be repeated up to 'Max.Init.Retransmits' times.
5966  *     After that, the endpoint MUST abort the initialization process and
5967  *     report the error to SCTP user.
5968  *
5969  * Outputs
5970  * (timers, events)
5971  *
5972  */
5973 enum sctp_disposition sctp_sf_t1_cookie_timer_expire(
5974                                         struct net *net,
5975                                         const struct sctp_endpoint *ep,
5976                                         const struct sctp_association *asoc,
5977                                         const union sctp_subtype type,
5978                                         void *arg,
5979                                         struct sctp_cmd_seq *commands)
5980 {
5981         int attempts = asoc->init_err_counter + 1;
5982         struct sctp_chunk *repl = NULL;
5983 
5984         pr_debug("%s: timer T1 expired (COOKIE-ECHO)\n", __func__);
5985 
5986         SCTP_INC_STATS(net, SCTP_MIB_T1_COOKIE_EXPIREDS);
5987 
5988         if (attempts <= asoc->max_init_attempts) {
5989                 repl = sctp_make_cookie_echo(asoc, NULL);
5990                 if (!repl)
5991                         return SCTP_DISPOSITION_NOMEM;
5992 
5993                 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT,
5994                                 SCTP_CHUNK(repl));
5995                 /* Issue a sideeffect to do the needed accounting. */
5996                 sctp_add_cmd_sf(commands, SCTP_CMD_COOKIEECHO_RESTART,
5997                                 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE));
5998 
5999                 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl));
6000         } else {
6001                 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
6002                                 SCTP_ERROR(ETIMEDOUT));
6003                 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED,
6004                                 SCTP_PERR(SCTP_ERROR_NO_ERROR));
6005                 return SCTP_DISPOSITION_DELETE_TCB;
6006         }
6007 
6008         return SCTP_DISPOSITION_CONSUME;
6009 }
6010 
6011 /* RFC2960 9.2 If the timer expires, the endpoint must re-send the SHUTDOWN
6012  * with the updated last sequential TSN received from its peer.
6013  *
6014  * An endpoint should limit the number of retransmission of the
6015  * SHUTDOWN chunk to the protocol parameter 'Association.Max.Retrans'.
6016  * If this threshold is exceeded the endpoint should destroy the TCB and
6017  * MUST report the peer endpoint unreachable to the upper layer (and
6018  * thus the association enters the CLOSED state).  The reception of any
6019  * packet from its peer (i.e. as the peer sends all of its queued DATA
6020  * chunks) should clear the endpoint's retransmission count and restart
6021  * the T2-Shutdown timer,  giving its peer ample opportunity to transmit
6022  * all of its queued DATA chunks that have not yet been sent.
6023  */
6024 enum sctp_disposition sctp_sf_t2_timer_expire(
6025                                         struct net *net,
6026                                         const struct sctp_endpoint *ep,
6027                                         const struct sctp_association *asoc,
6028                                         const union sctp_subtype type,
6029                                         void *arg,
6030                                         struct sctp_cmd_seq *commands)
6031 {
6032         struct sctp_chunk *reply = NULL;
6033 
6034         pr_debug("%s: timer T2 expired\n", __func__);
6035 
6036         SCTP_INC_STATS(net, SCTP_MIB_T2_SHUTDOWN_EXPIREDS);
6037 
6038         ((struct sctp_association *)asoc)->shutdown_retries++;
6039 
6040         if (asoc->overall_error_count >= asoc->max_retrans) {
6041                 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
6042                                 SCTP_ERROR(ETIMEDOUT));
6043                 /* Note:  CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */
6044                 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
6045                                 SCTP_PERR(SCTP_ERROR_NO_ERROR));
6046                 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
6047                 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
6048                 return SCTP_DISPOSITION_DELETE_TCB;
6049         }
6050 
6051         switch (asoc->state) {
6052         case SCTP_STATE_SHUTDOWN_SENT:
6053                 reply = sctp_make_shutdown(asoc, NULL);
6054                 break;
6055 
6056         case SCTP_STATE_SHUTDOWN_ACK_SENT:
6057                 reply = sctp_make_shutdown_ack(asoc, NULL);
6058                 break;
6059 
6060         default:
6061                 BUG();
6062                 break;
6063         }
6064 
6065         if (!reply)
6066                 goto nomem;
6067 
6068         /* Do some failure management (Section 8.2).
6069          * If we remove the transport an SHUTDOWN was last sent to, don't
6070          * do failure management.
6071          */
6072         if (asoc->shutdown_last_sent_to)
6073                 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE,
6074                                 SCTP_TRANSPORT(asoc->shutdown_last_sent_to));
6075 
6076         /* Set the transport for the SHUTDOWN/ACK chunk and the timeout for
6077          * the T2-shutdown timer.
6078          */
6079         sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply));
6080 
6081         /* Restart the T2-shutdown timer.  */
6082         sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
6083                         SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN));
6084         sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
6085         return SCTP_DISPOSITION_CONSUME;
6086 
6087 nomem:
6088         return SCTP_DISPOSITION_NOMEM;
6089 }
6090 
6091 /*
6092  * ADDIP Section 4.1 ASCONF Chunk Procedures
6093  * If the T4 RTO timer expires the endpoint should do B1 to B5
6094  */
6095 enum sctp_disposition sctp_sf_t4_timer_expire(
6096                                         struct net *net,
6097                                         const struct sctp_endpoint *ep,
6098                                         const struct sctp_association *asoc,
6099                                         const union sctp_subtype type,
6100                                         void *arg,
6101                                         struct sctp_cmd_seq *commands)
6102 {
6103         struct sctp_chunk *chunk = asoc->addip_last_asconf;
6104         struct sctp_transport *transport = chunk->transport;
6105 
6106         SCTP_INC_STATS(net, SCTP_MIB_T4_RTO_EXPIREDS);
6107 
6108         /* ADDIP 4.1 B1) Increment the error counters and perform path failure
6109          * detection on the appropriate destination address as defined in
6110          * RFC2960 [5] section 8.1 and 8.2.
6111          */
6112         if (transport)
6113                 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE,
6114                                 SCTP_TRANSPORT(transport));
6115 
6116         /* Reconfig T4 timer and transport. */
6117         sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk));
6118 
6119         /* ADDIP 4.1 B2) Increment the association error counters and perform
6120          * endpoint failure detection on the association as defined in
6121          * RFC2960 [5] section 8.1 and 8.2.
6122          * association error counter is incremented in SCTP_CMD_STRIKE.
6123          */
6124         if (asoc->overall_error_count >= asoc->max_retrans) {
6125                 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP,
6126                                 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
6127                 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
6128                                 SCTP_ERROR(ETIMEDOUT));
6129                 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
6130                                 SCTP_PERR(SCTP_ERROR_NO_ERROR));
6131                 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
6132                 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
6133                 return SCTP_DISPOSITION_ABORT;
6134         }
6135 
6136         /* ADDIP 4.1 B3) Back-off the destination address RTO value to which
6137          * the ASCONF chunk was sent by doubling the RTO timer value.
6138          * This is done in SCTP_CMD_STRIKE.
6139          */
6140 
6141         /* ADDIP 4.1 B4) Re-transmit the ASCONF Chunk last sent and if possible
6142          * choose an alternate destination address (please refer to RFC2960
6143          * [5] section 6.4.1). An endpoint MUST NOT add new parameters to this
6144          * chunk, it MUST be the same (including its serial number) as the last
6145          * ASCONF sent.
6146          */
6147         sctp_chunk_hold(asoc->addip_last_asconf);
6148         sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
6149                         SCTP_CHUNK(asoc->addip_last_asconf));
6150 
6151         /* ADDIP 4.1 B5) Restart the T-4 RTO timer. Note that if a different
6152          * destination is selected, then the RTO used will be that of the new
6153          * destination address.
6154          */
6155         sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART,
6156                         SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO));
6157 
6158         return SCTP_DISPOSITION_CONSUME;
6159 }
6160 
6161 /* sctpimpguide-05 Section 2.12.2
6162  * The sender of the SHUTDOWN MAY also start an overall guard timer
6163  * 'T5-shutdown-guard' to bound the overall time for shutdown sequence.
6164  * At the expiration of this timer the sender SHOULD abort the association
6165  * by sending an ABORT chunk.
6166  */
6167 enum sctp_disposition sctp_sf_t5_timer_expire(
6168                                         struct net *net,
6169                                         const struct sctp_endpoint *ep,
6170                                         const struct sctp_association *asoc,
6171                                         const union sctp_subtype type,
6172                                         void *arg,
6173                                         struct sctp_cmd_seq *commands)
6174 {
6175         struct sctp_chunk *reply = NULL;
6176 
6177         pr_debug("%s: timer T5 expired\n", __func__);
6178 
6179         SCTP_INC_STATS(net, SCTP_MIB_T5_SHUTDOWN_GUARD_EXPIREDS);
6180 
6181         reply = sctp_make_abort(asoc, NULL, 0);
6182         if (!reply)
6183                 goto nomem;
6184 
6185         sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply));
6186         sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
6187                         SCTP_ERROR(ETIMEDOUT));
6188         sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
6189                         SCTP_PERR(SCTP_ERROR_NO_ERROR));
6190 
6191         SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
6192         SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
6193 
6194         return SCTP_DISPOSITION_DELETE_TCB;
6195 nomem:
6196         return SCTP_DISPOSITION_NOMEM;
6197 }
6198 
6199 /* Handle expiration of AUTOCLOSE timer.  When the autoclose timer expires,
6200  * the association is automatically closed by starting the shutdown process.
6201  * The work that needs to be done is same as when SHUTDOWN is initiated by
6202  * the user.  So this routine looks same as sctp_sf_do_9_2_prm_shutdown().
6203  */
6204 enum sctp_disposition sctp_sf_autoclose_timer_expire(
6205                                         struct net *net,
6206                                         const struct sctp_endpoint *ep,
6207                                         const struct sctp_association *asoc,
6208                                         const union sctp_subtype type,
6209                                         void *arg,
6210                                         struct sctp_cmd_seq *commands)
6211 {
6212         enum sctp_disposition disposition;
6213 
6214         SCTP_INC_STATS(net, SCTP_MIB_AUTOCLOSE_EXPIREDS);
6215 
6216         /* From 9.2 Shutdown of an Association
6217          * Upon receipt of the SHUTDOWN primitive from its upper
6218          * layer, the endpoint enters SHUTDOWN-PENDING state and
6219          * remains there until all outstanding data has been
6220          * acknowledged by its peer. The endpoint accepts no new data
6221          * from its upper layer, but retransmits data to the far end
6222          * if necessary to fill gaps.
6223          */
6224         sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE,
6225                         SCTP_STATE(SCTP_STATE_SHUTDOWN_PENDING));
6226 
6227         disposition = SCTP_DISPOSITION_CONSUME;
6228         if (sctp_outq_is_empty(&asoc->outqueue)) {
6229                 disposition = sctp_sf_do_9_2_start_shutdown(net, ep, asoc, type,
6230                                                             NULL, commands);
6231         }
6232 
6233         return disposition;
6234 }
6235 
6236 /*****************************************************************************
6237  * These are sa state functions which could apply to all types of events.
6238  ****************************************************************************/
6239 
6240 /*
6241  * This table entry is not implemented.
6242  *
6243  * Inputs
6244  * (endpoint, asoc, chunk)
6245  *
6246  * The return value is the disposition of the chunk.
6247  */
6248 enum sctp_disposition sctp_sf_not_impl(struct net *net,
6249                                        const struct sctp_endpoint *ep,
6250                                        const struct sctp_association *asoc,
6251                                        const union sctp_subtype type,
6252                                        void *arg, struct sctp_cmd_seq *commands)
6253 {
6254         return SCTP_DISPOSITION_NOT_IMPL;
6255 }
6256 
6257 /*
6258  * This table entry represents a bug.
6259  *
6260  * Inputs
6261  * (endpoint, asoc, chunk)
6262  *
6263  * The return value is the disposition of the chunk.
6264  */
6265 enum sctp_disposition sctp_sf_bug(struct net *net,
6266                                   const struct sctp_endpoint *ep,
6267                                   const struct sctp_association *asoc,
6268                                   const union sctp_subtype type,
6269                                   void *arg, struct sctp_cmd_seq *commands)
6270 {
6271         return SCTP_DISPOSITION_BUG;
6272 }
6273 
6274 /*
6275  * This table entry represents the firing of a timer in the wrong state.
6276  * Since timer deletion cannot be guaranteed a timer 'may' end up firing
6277  * when the association is in the wrong state.   This event should
6278  * be ignored, so as to prevent any rearming of the timer.
6279  *
6280  * Inputs
6281  * (endpoint, asoc, chunk)
6282  *
6283  * The return value is the disposition of the chunk.
6284  */
6285 enum sctp_disposition sctp_sf_timer_ignore(struct net *net,
6286                                            const struct sctp_endpoint *ep,
6287                                            const struct sctp_association *asoc,
6288                                            const union sctp_subtype type,
6289                                            void *arg,
6290                                            struct sctp_cmd_seq *commands)
6291 {
6292         pr_debug("%s: timer %d ignored\n", __func__, type.chunk);
6293 
6294         return SCTP_DISPOSITION_CONSUME;
6295 }
6296 
6297 /********************************************************************
6298  * 2nd Level Abstractions
6299  ********************************************************************/
6300 
6301 /* Pull the SACK chunk based on the SACK header. */
6302 static struct sctp_sackhdr *sctp_sm_pull_sack(struct sctp_chunk *chunk)
6303 {
6304         struct sctp_sackhdr *sack;
6305         __u16 num_dup_tsns;
6306         unsigned int len;
6307         __u16 num_blocks;
6308 
6309         /* Protect ourselves from reading too far into
6310          * the skb from a bogus sender.
6311          */
6312         sack = (struct sctp_sackhdr *) chunk->skb->data;
6313 
6314         num_blocks = ntohs(sack->num_gap_ack_blocks);
6315         num_dup_tsns = ntohs(sack->num_dup_tsns);
6316         len = sizeof(struct sctp_sackhdr);
6317         len += (num_blocks + num_dup_tsns) * sizeof(__u32);
6318         if (len > chunk->skb->len)
6319                 return NULL;
6320 
6321         skb_pull(chunk->skb, len);
6322 
6323         return sack;
6324 }
6325 
6326 /* Create an ABORT packet to be sent as a response, with the specified
6327  * error causes.
6328  */
6329 static struct sctp_packet *sctp_abort_pkt_new(
6330                                         struct net *net,
6331                                         const struct sctp_endpoint *ep,
6332                                         const struct sctp_association *asoc,
6333                                         struct sctp_chunk *chunk,
6334                                         const void *payload, size_t paylen)
6335 {
6336         struct sctp_packet *packet;
6337         struct sctp_chunk *abort;
6338 
6339         packet = sctp_ootb_pkt_new(net, asoc, chunk);
6340 
6341         if (packet) {
6342                 /* Make an ABORT.
6343                  * The T bit will be set if the asoc is NULL.
6344                  */
6345                 abort = sctp_make_abort(asoc, chunk, paylen);
6346                 if (!abort) {
6347                         sctp_ootb_pkt_free(packet);
6348                         return NULL;
6349                 }
6350 
6351                 /* Reflect vtag if T-Bit is set */
6352                 if (sctp_test_T_bit(abort))
6353                         packet->vtag = ntohl(chunk->sctp_hdr->vtag);
6354 
6355                 /* Add specified error causes, i.e., payload, to the
6356                  * end of the chunk.
6357                  */
6358                 sctp_addto_chunk(abort, paylen, payload);
6359 
6360                 /* Set the skb to the belonging sock for accounting.  */
6361                 abort->skb->sk = ep->base.sk;
6362 
6363                 sctp_packet_append_chunk(packet, abort);
6364 
6365         }
6366 
6367         return packet;
6368 }
6369 
6370 /* Allocate a packet for responding in the OOTB conditions.  */
6371 static struct sctp_packet *sctp_ootb_pkt_new(
6372                                         struct net *net,
6373                                         const struct sctp_association *asoc,
6374                                         const struct sctp_chunk *chunk)
6375 {
6376         struct sctp_transport *transport;
6377         struct sctp_packet *packet;
6378         __u16 sport, dport;
6379         __u32 vtag;
6380 
6381         /* Get the source and destination port from the inbound packet.  */
6382         sport = ntohs(chunk->sctp_hdr->dest);
6383         dport = ntohs(chunk->sctp_hdr->source);
6384 
6385         /* The V-tag is going to be the same as the inbound packet if no
6386          * association exists, otherwise, use the peer's vtag.
6387          */
6388         if (asoc) {
6389                 /* Special case the INIT-ACK as there is no peer's vtag
6390                  * yet.
6391                  */
6392                 switch (chunk->chunk_hdr->type) {
6393                 case SCTP_CID_INIT:
6394                 case SCTP_CID_INIT_ACK:
6395                 {
6396                         struct sctp_initack_chunk *initack;
6397 
6398                         initack = (struct sctp_initack_chunk *)chunk->chunk_hdr;
6399                         vtag = ntohl(initack->init_hdr.init_tag);
6400                         break;
6401                 }
6402                 default:
6403                         vtag = asoc->peer.i.init_tag;
6404                         break;
6405                 }
6406         } else {
6407                 /* Special case the INIT and stale COOKIE_ECHO as there is no
6408                  * vtag yet.
6409                  */
6410                 switch (chunk->chunk_hdr->type) {
6411                 case SCTP_CID_INIT:
6412                 {
6413                         struct sctp_init_chunk *init;
6414 
6415                         init = (struct sctp_init_chunk *)chunk->chunk_hdr;
6416                         vtag = ntohl(init->init_hdr.init_tag);
6417                         break;
6418                 }
6419                 default:
6420                         vtag = ntohl(chunk->sctp_hdr->vtag);
6421                         break;
6422                 }
6423         }
6424 
6425         /* Make a transport for the bucket, Eliza... */
6426         transport = sctp_transport_new(net, sctp_source(chunk), GFP_ATOMIC);
6427         if (!transport)
6428                 goto nomem;
6429 
6430         transport->encap_port = SCTP_INPUT_CB(chunk->skb)->encap_port;
6431 
6432         /* Cache a route for the transport with the chunk's destination as
6433          * the source address.
6434          */
6435         sctp_transport_route(transport, (union sctp_addr *)&chunk->dest,
6436                              sctp_sk(net->sctp.ctl_sock));
6437 
6438         packet = &transport->packet;
6439         sctp_packet_init(packet, transport, sport, dport);
6440         sctp_packet_config(packet, vtag, 0);
6441 
6442         return packet;
6443 
6444 nomem:
6445         return NULL;
6446 }
6447 
6448 /* Free the packet allocated earlier for responding in the OOTB condition.  */
6449 void sctp_ootb_pkt_free(struct sctp_packet *packet)
6450 {
6451         sctp_transport_free(packet->transport);
6452 }
6453 
6454 /* Send a stale cookie error when a invalid COOKIE ECHO chunk is found  */
6455 static void sctp_send_stale_cookie_err(struct net *net,
6456                                        const struct sctp_endpoint *ep,
6457                                        const struct sctp_association *asoc,
6458                                        const struct sctp_chunk *chunk,
6459                                        struct sctp_cmd_seq *commands,
6460                                        struct sctp_chunk *err_chunk)
6461 {
6462         struct sctp_packet *packet;
6463 
6464         if (err_chunk) {
6465                 packet = sctp_ootb_pkt_new(net, asoc, chunk);
6466                 if (packet) {
6467                         struct sctp_signed_cookie *cookie;
6468 
6469                         /* Override the OOTB vtag from the cookie. */
6470                         cookie = chunk->subh.cookie_hdr;
6471                         packet->vtag = cookie->c.peer_vtag;
6472 
6473                         /* Set the skb to the belonging sock for accounting. */
6474                         err_chunk->skb->sk = ep->base.sk;
6475                         sctp_packet_append_chunk(packet, err_chunk);
6476                         sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT,
6477                                         SCTP_PACKET(packet));
6478                         SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
6479                 } else
6480                         sctp_chunk_free (err_chunk);
6481         }
6482 }
6483 
6484 
6485 /* Process a data chunk */
6486 static int sctp_eat_data(const struct sctp_association *asoc,
6487                          struct sctp_chunk *chunk,
6488                          struct sctp_cmd_seq *commands)
6489 {
6490         struct sctp_tsnmap *map = (struct sctp_tsnmap *)&asoc->peer.tsn_map;
6491         struct sock *sk = asoc->base.sk;
6492         struct net *net = sock_net(sk);
6493         struct sctp_datahdr *data_hdr;
6494         struct sctp_chunk *err;
6495         enum sctp_verb deliver;
6496         size_t datalen;
6497         __u32 tsn;
6498         int tmp;
6499 
6500         data_hdr = (struct sctp_datahdr *)chunk->skb->data;
6501         chunk->subh.data_hdr = data_hdr;
6502         skb_pull(chunk->skb, sctp_datahdr_len(&asoc->stream));
6503 
6504         tsn = ntohl(data_hdr->tsn);
6505         pr_debug("%s: TSN 0x%x\n", __func__, tsn);
6506 
6507         /* ASSERT:  Now skb->data is really the user data.  */
6508 
6509         /* Process ECN based congestion.
6510          *
6511          * Since the chunk structure is reused for all chunks within
6512          * a packet, we use ecn_ce_done to track if we've already
6513          * done CE processing for this packet.
6514          *
6515          * We need to do ECN processing even if we plan to discard the
6516          * chunk later.
6517          */
6518 
6519         if (asoc->peer.ecn_capable && !chunk->ecn_ce_done) {
6520                 struct sctp_af *af = SCTP_INPUT_CB(chunk->skb)->af;
6521                 chunk->ecn_ce_done = 1;
6522 
6523                 if (af->is_ce(sctp_gso_headskb(chunk->skb))) {
6524                         /* Do real work as side effect. */
6525                         sctp_add_cmd_sf(commands, SCTP_CMD_ECN_CE,
6526                                         SCTP_U32(tsn));
6527                 }
6528         }
6529 
6530         tmp = sctp_tsnmap_check(&asoc->peer.tsn_map, tsn);
6531         if (tmp < 0) {
6532                 /* The TSN is too high--silently discard the chunk and
6533                  * count on it getting retransmitted later.
6534                  */
6535                 if (chunk->asoc)
6536                         chunk->asoc->stats.outofseqtsns++;
6537                 return SCTP_IERROR_HIGH_TSN;
6538         } else if (tmp > 0) {
6539                 /* This is a duplicate.  Record it.  */
6540                 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_DUP, SCTP_U32(tsn));
6541                 return SCTP_IERROR_DUP_TSN;
6542         }
6543 
6544         /* This is a new TSN.  */
6545 
6546         /* Discard if there is no room in the receive window.
6547          * Actually, allow a little bit of overflow (up to a MTU).
6548          */
6549         datalen = ntohs(chunk->chunk_hdr->length);
6550         datalen -= sctp_datachk_len(&asoc->stream);
6551 
6552         deliver = SCTP_CMD_CHUNK_ULP;
6553 
6554         /* Think about partial delivery. */
6555         if ((datalen >= asoc->rwnd) && (!asoc->ulpq.pd_mode)) {
6556 
6557                 /* Even if we don't accept this chunk there is
6558                  * memory pressure.
6559                  */
6560                 sctp_add_cmd_sf(commands, SCTP_CMD_PART_DELIVER, SCTP_NULL());
6561         }
6562 
6563         /* Spill over rwnd a little bit.  Note: While allowed, this spill over
6564          * seems a bit troublesome in that frag_point varies based on
6565          * PMTU.  In cases, such as loopback, this might be a rather
6566          * large spill over.
6567          */
6568         if ((!chunk->data_accepted) && (!asoc->rwnd || asoc->rwnd_over ||
6569             (datalen > asoc->rwnd + asoc->frag_point))) {
6570 
6571                 /* If this is the next TSN, consider reneging to make
6572                  * room.   Note: Playing nice with a confused sender.  A
6573                  * malicious sender can still eat up all our buffer
6574                  * space and in the future we may want to detect and
6575                  * do more drastic reneging.
6576                  */
6577                 if (sctp_tsnmap_has_gap(map) &&
6578                     (sctp_tsnmap_get_ctsn(map) + 1) == tsn) {
6579                         pr_debug("%s: reneging for tsn:%u\n", __func__, tsn);
6580                         deliver = SCTP_CMD_RENEGE;
6581                 } else {
6582                         pr_debug("%s: discard tsn:%u len:%zu, rwnd:%d\n",
6583                                  __func__, tsn, datalen, asoc->rwnd);
6584 
6585                         return SCTP_IERROR_IGNORE_TSN;
6586                 }
6587         }
6588 
6589         /*
6590          * Also try to renege to limit our memory usage in the event that
6591          * we are under memory pressure
6592          * If we can't renege, don't worry about it, the sk_rmem_schedule
6593          * in sctp_ulpevent_make_rcvmsg will drop the frame if we grow our
6594          * memory usage too much
6595          */
6596         if (sk_under_memory_pressure(sk)) {
6597                 if (sctp_tsnmap_has_gap(map) &&
6598                     (sctp_tsnmap_get_ctsn(map) + 1) == tsn) {
6599                         pr_debug("%s: under pressure, reneging for tsn:%u\n",
6600                                  __func__, tsn);
6601                         deliver = SCTP_CMD_RENEGE;
6602                 }
6603         }
6604 
6605         /*
6606          * Section 3.3.10.9 No User Data (9)
6607          *
6608          * Cause of error
6609          * ---------------
6610          * No User Data:  This error cause is returned to the originator of a
6611          * DATA chunk if a received DATA chunk has no user data.
6612          */
6613         if (unlikely(0 == datalen)) {
6614                 err = sctp_make_abort_no_data(asoc, chunk, tsn);
6615                 if (err) {
6616                         sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
6617                                         SCTP_CHUNK(err));
6618                 }
6619                 /* We are going to ABORT, so we might as well stop
6620                  * processing the rest of the chunks in the packet.
6621                  */
6622                 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL());
6623                 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR,
6624                                 SCTP_ERROR(ECONNABORTED));
6625                 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED,
6626                                 SCTP_PERR(SCTP_ERROR_NO_DATA));
6627                 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS);
6628                 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB);
6629                 return SCTP_IERROR_NO_DATA;
6630         }
6631 
6632         chunk->data_accepted = 1;
6633 
6634         /* Note: Some chunks may get overcounted (if we drop) or overcounted
6635          * if we renege and the chunk arrives again.
6636          */
6637         if (chunk->chunk_hdr->flags & SCTP_DATA_UNORDERED) {
6638                 SCTP_INC_STATS(net, SCTP_MIB_INUNORDERCHUNKS);
6639                 if (chunk->asoc)
6640                         chunk->asoc->stats.iuodchunks++;
6641         } else {
6642                 SCTP_INC_STATS(net, SCTP_MIB_INORDERCHUNKS);
6643                 if (chunk->asoc)
6644                         chunk->asoc->stats.iodchunks++;
6645         }
6646 
6647         /* RFC 2960 6.5 Stream Identifier and Stream Sequence Number
6648          *
6649          * If an endpoint receive a DATA chunk with an invalid stream
6650          * identifier, it shall acknowledge the reception of the DATA chunk
6651          * following the normal procedure, immediately send an ERROR chunk
6652          * with cause set to "Invalid Stream Identifier" (See Section 3.3.10)
6653          * and discard the DATA chunk.
6654          */
6655         if (ntohs(data_hdr->stream) >= asoc->stream.incnt) {
6656                 /* Mark tsn as received even though we drop it */
6657                 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_TSN, SCTP_U32(tsn));
6658 
6659                 err = sctp_make_op_error(asoc, chunk, SCTP_ERROR_INV_STRM,
6660                                          &data_hdr->stream,
6661                                          sizeof(data_hdr->stream),
6662                                          sizeof(u16));
6663                 if (err)
6664                         sctp_add_cmd_sf(commands, SCTP_CMD_REPLY,
6665                                         SCTP_CHUNK(err));
6666                 return SCTP_IERROR_BAD_STREAM;
6667         }
6668 
6669         /* Check to see if the SSN is possible for this TSN.
6670          * The biggest gap we can record is 4K wide.  Since SSNs wrap
6671          * at an unsigned short, there is no way that an SSN can
6672          * wrap and for a valid TSN.  We can simply check if the current
6673          * SSN is smaller then the next expected one.  If it is, it wrapped
6674          * and is invalid.
6675          */
6676         if (!asoc->stream.si->validate_data(chunk))
6677                 return SCTP_IERROR_PROTO_VIOLATION;
6678 
6679         /* Send the data up to the user.  Note:  Schedule  the
6680          * SCTP_CMD_CHUNK_ULP cmd before the SCTP_CMD_GEN_SACK, as the SACK
6681          * chunk needs the updated rwnd.
6682          */
6683         sctp_add_cmd_sf(commands, deliver, SCTP_CHUNK(chunk));
6684 
6685         return SCTP_IERROR_NO_ERROR;
6686 }
6687 

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