1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /* RxRPC packet reception
3 *
4 * Copyright (C) 2007, 2016, 2022 Red Hat, Inc. All Rights Reserved.
5 * Written by David Howells (dhowells@redhat.com)
6 */
7
8 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
9
10 #include "ar-internal.h"
11
12 static int rxrpc_input_packet_on_conn(struct rxrpc_connection *conn,
13 struct sockaddr_rxrpc *peer_srx,
14 struct sk_buff *skb);
15
16 /*
17 * handle data received on the local endpoint
18 * - may be called in interrupt context
19 *
20 * [!] Note that as this is called from the encap_rcv hook, the socket is not
21 * held locked by the caller and nothing prevents sk_user_data on the UDP from
22 * being cleared in the middle of processing this function.
23 *
24 * Called with the RCU read lock held from the IP layer via UDP.
25 */
26 int rxrpc_encap_rcv(struct sock *udp_sk, struct sk_buff *skb)
27 {
28 struct sk_buff_head *rx_queue;
29 struct rxrpc_local *local = rcu_dereference_sk_user_data(udp_sk);
30 struct task_struct *io_thread;
31
32 if (unlikely(!local)) {
33 kfree_skb(skb);
34 return 0;
35 }
36 io_thread = READ_ONCE(local->io_thread);
37 if (!io_thread) {
38 kfree_skb(skb);
39 return 0;
40 }
41 if (skb->tstamp == 0)
42 skb->tstamp = ktime_get_real();
43
44 skb->mark = RXRPC_SKB_MARK_PACKET;
45 rxrpc_new_skb(skb, rxrpc_skb_new_encap_rcv);
46 rx_queue = &local->rx_queue;
47 #ifdef CONFIG_AF_RXRPC_INJECT_RX_DELAY
48 if (rxrpc_inject_rx_delay ||
49 !skb_queue_empty(&local->rx_delay_queue)) {
50 skb->tstamp = ktime_add_ms(skb->tstamp, rxrpc_inject_rx_delay);
51 rx_queue = &local->rx_delay_queue;
52 }
53 #endif
54
55 skb_queue_tail(rx_queue, skb);
56 wake_up_process(io_thread);
57 return 0;
58 }
59
60 /*
61 * Handle an error received on the local endpoint.
62 */
63 void rxrpc_error_report(struct sock *sk)
64 {
65 struct rxrpc_local *local;
66 struct sk_buff *skb;
67
68 rcu_read_lock();
69 local = rcu_dereference_sk_user_data(sk);
70 if (unlikely(!local)) {
71 rcu_read_unlock();
72 return;
73 }
74
75 while ((skb = skb_dequeue(&sk->sk_error_queue))) {
76 skb->mark = RXRPC_SKB_MARK_ERROR;
77 rxrpc_new_skb(skb, rxrpc_skb_new_error_report);
78 skb_queue_tail(&local->rx_queue, skb);
79 }
80
81 rxrpc_wake_up_io_thread(local);
82 rcu_read_unlock();
83 }
84
85 /*
86 * Directly produce an abort from a packet.
87 */
88 bool rxrpc_direct_abort(struct sk_buff *skb, enum rxrpc_abort_reason why,
89 s32 abort_code, int err)
90 {
91 struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
92
93 trace_rxrpc_abort(0, why, sp->hdr.cid, sp->hdr.callNumber, sp->hdr.seq,
94 abort_code, err);
95 skb->mark = RXRPC_SKB_MARK_REJECT_ABORT;
96 skb->priority = abort_code;
97 return false;
98 }
99
100 static bool rxrpc_bad_message(struct sk_buff *skb, enum rxrpc_abort_reason why)
101 {
102 return rxrpc_direct_abort(skb, why, RX_PROTOCOL_ERROR, -EBADMSG);
103 }
104
105 #define just_discard true
106
107 /*
108 * Process event packets targeted at a local endpoint.
109 */
110 static bool rxrpc_input_version(struct rxrpc_local *local, struct sk_buff *skb)
111 {
112 struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
113 char v;
114
115 _enter("");
116
117 rxrpc_see_skb(skb, rxrpc_skb_see_version);
118 if (skb_copy_bits(skb, sizeof(struct rxrpc_wire_header), &v, 1) >= 0) {
119 if (v == 0)
120 rxrpc_send_version_request(local, &sp->hdr, skb);
121 }
122
123 return true;
124 }
125
126 /*
127 * Extract the wire header from a packet and translate the byte order.
128 */
129 static bool rxrpc_extract_header(struct rxrpc_skb_priv *sp,
130 struct sk_buff *skb)
131 {
132 struct rxrpc_wire_header whdr;
133 struct rxrpc_ackpacket ack;
134
135 /* dig out the RxRPC connection details */
136 if (skb_copy_bits(skb, 0, &whdr, sizeof(whdr)) < 0)
137 return rxrpc_bad_message(skb, rxrpc_badmsg_short_hdr);
138
139 memset(sp, 0, sizeof(*sp));
140 sp->hdr.epoch = ntohl(whdr.epoch);
141 sp->hdr.cid = ntohl(whdr.cid);
142 sp->hdr.callNumber = ntohl(whdr.callNumber);
143 sp->hdr.seq = ntohl(whdr.seq);
144 sp->hdr.serial = ntohl(whdr.serial);
145 sp->hdr.flags = whdr.flags;
146 sp->hdr.type = whdr.type;
147 sp->hdr.userStatus = whdr.userStatus;
148 sp->hdr.securityIndex = whdr.securityIndex;
149 sp->hdr._rsvd = ntohs(whdr._rsvd);
150 sp->hdr.serviceId = ntohs(whdr.serviceId);
151
152 if (sp->hdr.type == RXRPC_PACKET_TYPE_ACK) {
153 if (skb_copy_bits(skb, sizeof(whdr), &ack, sizeof(ack)) < 0)
154 return rxrpc_bad_message(skb, rxrpc_badmsg_short_ack);
155 sp->ack.first_ack = ntohl(ack.firstPacket);
156 sp->ack.prev_ack = ntohl(ack.previousPacket);
157 sp->ack.acked_serial = ntohl(ack.serial);
158 sp->ack.reason = ack.reason;
159 sp->ack.nr_acks = ack.nAcks;
160 }
161 return true;
162 }
163
164 /*
165 * Extract the abort code from an ABORT packet and stash it in skb->priority.
166 */
167 static bool rxrpc_extract_abort(struct sk_buff *skb)
168 {
169 __be32 wtmp;
170
171 if (skb_copy_bits(skb, sizeof(struct rxrpc_wire_header),
172 &wtmp, sizeof(wtmp)) < 0)
173 return false;
174 skb->priority = ntohl(wtmp);
175 return true;
176 }
177
178 /*
179 * Process packets received on the local endpoint
180 */
181 static bool rxrpc_input_packet(struct rxrpc_local *local, struct sk_buff **_skb)
182 {
183 struct rxrpc_connection *conn;
184 struct sockaddr_rxrpc peer_srx;
185 struct rxrpc_skb_priv *sp;
186 struct rxrpc_peer *peer = NULL;
187 struct sk_buff *skb = *_skb;
188 bool ret = false;
189
190 skb_pull(skb, sizeof(struct udphdr));
191
192 sp = rxrpc_skb(skb);
193
194 /* dig out the RxRPC connection details */
195 if (!rxrpc_extract_header(sp, skb))
196 return just_discard;
197
198 if (IS_ENABLED(CONFIG_AF_RXRPC_INJECT_LOSS)) {
199 static int lose;
200 if ((lose++ & 7) == 7) {
201 trace_rxrpc_rx_lose(sp);
202 return just_discard;
203 }
204 }
205
206 trace_rxrpc_rx_packet(sp);
207
208 switch (sp->hdr.type) {
209 case RXRPC_PACKET_TYPE_VERSION:
210 if (rxrpc_to_client(sp))
211 return just_discard;
212 return rxrpc_input_version(local, skb);
213
214 case RXRPC_PACKET_TYPE_BUSY:
215 if (rxrpc_to_server(sp))
216 return just_discard;
217 fallthrough;
218 case RXRPC_PACKET_TYPE_ACK:
219 case RXRPC_PACKET_TYPE_ACKALL:
220 if (sp->hdr.callNumber == 0)
221 return rxrpc_bad_message(skb, rxrpc_badmsg_zero_call);
222 break;
223 case RXRPC_PACKET_TYPE_ABORT:
224 if (!rxrpc_extract_abort(skb))
225 return just_discard; /* Just discard if malformed */
226 break;
227
228 case RXRPC_PACKET_TYPE_DATA:
229 if (sp->hdr.callNumber == 0)
230 return rxrpc_bad_message(skb, rxrpc_badmsg_zero_call);
231 if (sp->hdr.seq == 0)
232 return rxrpc_bad_message(skb, rxrpc_badmsg_zero_seq);
233
234 /* Unshare the packet so that it can be modified for in-place
235 * decryption.
236 */
237 if (sp->hdr.securityIndex != 0) {
238 skb = skb_unshare(skb, GFP_ATOMIC);
239 if (!skb) {
240 rxrpc_eaten_skb(*_skb, rxrpc_skb_eaten_by_unshare_nomem);
241 *_skb = NULL;
242 return just_discard;
243 }
244
245 if (skb != *_skb) {
246 rxrpc_eaten_skb(*_skb, rxrpc_skb_eaten_by_unshare);
247 *_skb = skb;
248 rxrpc_new_skb(skb, rxrpc_skb_new_unshared);
249 sp = rxrpc_skb(skb);
250 }
251 }
252 break;
253
254 case RXRPC_PACKET_TYPE_CHALLENGE:
255 if (rxrpc_to_server(sp))
256 return just_discard;
257 break;
258 case RXRPC_PACKET_TYPE_RESPONSE:
259 if (rxrpc_to_client(sp))
260 return just_discard;
261 break;
262
263 /* Packet types 9-11 should just be ignored. */
264 case RXRPC_PACKET_TYPE_PARAMS:
265 case RXRPC_PACKET_TYPE_10:
266 case RXRPC_PACKET_TYPE_11:
267 return just_discard;
268
269 default:
270 return rxrpc_bad_message(skb, rxrpc_badmsg_unsupported_packet);
271 }
272
273 if (sp->hdr.serviceId == 0)
274 return rxrpc_bad_message(skb, rxrpc_badmsg_zero_service);
275
276 if (WARN_ON_ONCE(rxrpc_extract_addr_from_skb(&peer_srx, skb) < 0))
277 return just_discard; /* Unsupported address type. */
278
279 if (peer_srx.transport.family != local->srx.transport.family &&
280 (peer_srx.transport.family == AF_INET &&
281 local->srx.transport.family != AF_INET6)) {
282 pr_warn_ratelimited("AF_RXRPC: Protocol mismatch %u not %u\n",
283 peer_srx.transport.family,
284 local->srx.transport.family);
285 return just_discard; /* Wrong address type. */
286 }
287
288 if (rxrpc_to_client(sp)) {
289 rcu_read_lock();
290 conn = rxrpc_find_client_connection_rcu(local, &peer_srx, skb);
291 conn = rxrpc_get_connection_maybe(conn, rxrpc_conn_get_call_input);
292 rcu_read_unlock();
293 if (!conn)
294 return rxrpc_protocol_error(skb, rxrpc_eproto_no_client_conn);
295
296 ret = rxrpc_input_packet_on_conn(conn, &peer_srx, skb);
297 rxrpc_put_connection(conn, rxrpc_conn_put_call_input);
298 return ret;
299 }
300
301 /* We need to look up service connections by the full protocol
302 * parameter set. We look up the peer first as an intermediate step
303 * and then the connection from the peer's tree.
304 */
305 rcu_read_lock();
306
307 peer = rxrpc_lookup_peer_rcu(local, &peer_srx);
308 if (!peer) {
309 rcu_read_unlock();
310 return rxrpc_new_incoming_call(local, NULL, NULL, &peer_srx, skb);
311 }
312
313 conn = rxrpc_find_service_conn_rcu(peer, skb);
314 conn = rxrpc_get_connection_maybe(conn, rxrpc_conn_get_call_input);
315 if (conn) {
316 rcu_read_unlock();
317 ret = rxrpc_input_packet_on_conn(conn, &peer_srx, skb);
318 rxrpc_put_connection(conn, rxrpc_conn_put_call_input);
319 return ret;
320 }
321
322 peer = rxrpc_get_peer_maybe(peer, rxrpc_peer_get_input);
323 rcu_read_unlock();
324
325 ret = rxrpc_new_incoming_call(local, peer, NULL, &peer_srx, skb);
326 rxrpc_put_peer(peer, rxrpc_peer_put_input);
327 return ret;
328 }
329
330 /*
331 * Deal with a packet that's associated with an extant connection.
332 */
333 static int rxrpc_input_packet_on_conn(struct rxrpc_connection *conn,
334 struct sockaddr_rxrpc *peer_srx,
335 struct sk_buff *skb)
336 {
337 struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
338 struct rxrpc_channel *chan;
339 struct rxrpc_call *call = NULL;
340 unsigned int channel;
341 bool ret;
342
343 if (sp->hdr.securityIndex != conn->security_ix)
344 return rxrpc_direct_abort(skb, rxrpc_eproto_wrong_security,
345 RXKADINCONSISTENCY, -EBADMSG);
346
347 if (sp->hdr.serviceId != conn->service_id) {
348 int old_id;
349
350 if (!test_bit(RXRPC_CONN_PROBING_FOR_UPGRADE, &conn->flags))
351 return rxrpc_protocol_error(skb, rxrpc_eproto_reupgrade);
352
353 old_id = cmpxchg(&conn->service_id, conn->orig_service_id,
354 sp->hdr.serviceId);
355 if (old_id != conn->orig_service_id &&
356 old_id != sp->hdr.serviceId)
357 return rxrpc_protocol_error(skb, rxrpc_eproto_bad_upgrade);
358 }
359
360 if (after(sp->hdr.serial, conn->hi_serial))
361 conn->hi_serial = sp->hdr.serial;
362
363 /* It's a connection-level packet if the call number is 0. */
364 if (sp->hdr.callNumber == 0)
365 return rxrpc_input_conn_packet(conn, skb);
366
367 /* Call-bound packets are routed by connection channel. */
368 channel = sp->hdr.cid & RXRPC_CHANNELMASK;
369 chan = &conn->channels[channel];
370
371 /* Ignore really old calls */
372 if (sp->hdr.callNumber < chan->last_call)
373 return just_discard;
374
375 if (sp->hdr.callNumber == chan->last_call) {
376 if (chan->call ||
377 sp->hdr.type == RXRPC_PACKET_TYPE_ABORT)
378 return just_discard;
379
380 /* For the previous service call, if completed successfully, we
381 * discard all further packets.
382 */
383 if (rxrpc_conn_is_service(conn) &&
384 chan->last_type == RXRPC_PACKET_TYPE_ACK)
385 return just_discard;
386
387 /* But otherwise we need to retransmit the final packet from
388 * data cached in the connection record.
389 */
390 if (sp->hdr.type == RXRPC_PACKET_TYPE_DATA)
391 trace_rxrpc_rx_data(chan->call_debug_id,
392 sp->hdr.seq,
393 sp->hdr.serial,
394 sp->hdr.flags);
395 rxrpc_conn_retransmit_call(conn, skb, channel);
396 return just_discard;
397 }
398
399 call = rxrpc_try_get_call(chan->call, rxrpc_call_get_input);
400
401 if (sp->hdr.callNumber > chan->call_id) {
402 if (rxrpc_to_client(sp)) {
403 rxrpc_put_call(call, rxrpc_call_put_input);
404 return rxrpc_protocol_error(skb,
405 rxrpc_eproto_unexpected_implicit_end);
406 }
407
408 if (call) {
409 rxrpc_implicit_end_call(call, skb);
410 rxrpc_put_call(call, rxrpc_call_put_input);
411 call = NULL;
412 }
413 }
414
415 if (!call) {
416 if (rxrpc_to_client(sp))
417 return rxrpc_protocol_error(skb, rxrpc_eproto_no_client_call);
418 return rxrpc_new_incoming_call(conn->local, conn->peer, conn,
419 peer_srx, skb);
420 }
421
422 ret = rxrpc_input_call_event(call, skb);
423 rxrpc_put_call(call, rxrpc_call_put_input);
424 return ret;
425 }
426
427 /*
428 * I/O and event handling thread.
429 */
430 int rxrpc_io_thread(void *data)
431 {
432 struct rxrpc_connection *conn;
433 struct sk_buff_head rx_queue;
434 struct rxrpc_local *local = data;
435 struct rxrpc_call *call;
436 struct sk_buff *skb;
437 #ifdef CONFIG_AF_RXRPC_INJECT_RX_DELAY
438 ktime_t now;
439 #endif
440 bool should_stop;
441
442 complete(&local->io_thread_ready);
443
444 skb_queue_head_init(&rx_queue);
445
446 set_user_nice(current, MIN_NICE);
447
448 for (;;) {
449 rxrpc_inc_stat(local->rxnet, stat_io_loop);
450
451 /* Deal with connections that want immediate attention. */
452 conn = list_first_entry_or_null(&local->conn_attend_q,
453 struct rxrpc_connection,
454 attend_link);
455 if (conn) {
456 spin_lock_bh(&local->lock);
457 list_del_init(&conn->attend_link);
458 spin_unlock_bh(&local->lock);
459
460 rxrpc_input_conn_event(conn, NULL);
461 rxrpc_put_connection(conn, rxrpc_conn_put_poke);
462 continue;
463 }
464
465 if (test_and_clear_bit(RXRPC_CLIENT_CONN_REAP_TIMER,
466 &local->client_conn_flags))
467 rxrpc_discard_expired_client_conns(local);
468
469 /* Deal with calls that want immediate attention. */
470 if ((call = list_first_entry_or_null(&local->call_attend_q,
471 struct rxrpc_call,
472 attend_link))) {
473 spin_lock_bh(&local->lock);
474 list_del_init(&call->attend_link);
475 spin_unlock_bh(&local->lock);
476
477 trace_rxrpc_call_poked(call);
478 rxrpc_input_call_event(call, NULL);
479 rxrpc_put_call(call, rxrpc_call_put_poke);
480 continue;
481 }
482
483 if (!list_empty(&local->new_client_calls))
484 rxrpc_connect_client_calls(local);
485
486 /* Process received packets and errors. */
487 if ((skb = __skb_dequeue(&rx_queue))) {
488 struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
489 switch (skb->mark) {
490 case RXRPC_SKB_MARK_PACKET:
491 skb->priority = 0;
492 if (!rxrpc_input_packet(local, &skb))
493 rxrpc_reject_packet(local, skb);
494 trace_rxrpc_rx_done(skb->mark, skb->priority);
495 rxrpc_free_skb(skb, rxrpc_skb_put_input);
496 break;
497 case RXRPC_SKB_MARK_ERROR:
498 rxrpc_input_error(local, skb);
499 rxrpc_free_skb(skb, rxrpc_skb_put_error_report);
500 break;
501 case RXRPC_SKB_MARK_SERVICE_CONN_SECURED:
502 rxrpc_input_conn_event(sp->conn, skb);
503 rxrpc_put_connection(sp->conn, rxrpc_conn_put_poke);
504 rxrpc_free_skb(skb, rxrpc_skb_put_conn_secured);
505 break;
506 default:
507 WARN_ON_ONCE(1);
508 rxrpc_free_skb(skb, rxrpc_skb_put_unknown);
509 break;
510 }
511 continue;
512 }
513
514 /* Inject a delay into packets if requested. */
515 #ifdef CONFIG_AF_RXRPC_INJECT_RX_DELAY
516 now = ktime_get_real();
517 while ((skb = skb_peek(&local->rx_delay_queue))) {
518 if (ktime_before(now, skb->tstamp))
519 break;
520 skb = skb_dequeue(&local->rx_delay_queue);
521 skb_queue_tail(&local->rx_queue, skb);
522 }
523 #endif
524
525 if (!skb_queue_empty(&local->rx_queue)) {
526 spin_lock_irq(&local->rx_queue.lock);
527 skb_queue_splice_tail_init(&local->rx_queue, &rx_queue);
528 spin_unlock_irq(&local->rx_queue.lock);
529 continue;
530 }
531
532 set_current_state(TASK_INTERRUPTIBLE);
533 should_stop = kthread_should_stop();
534 if (!skb_queue_empty(&local->rx_queue) ||
535 !list_empty(&local->call_attend_q) ||
536 !list_empty(&local->conn_attend_q) ||
537 !list_empty(&local->new_client_calls) ||
538 test_bit(RXRPC_CLIENT_CONN_REAP_TIMER,
539 &local->client_conn_flags)) {
540 __set_current_state(TASK_RUNNING);
541 continue;
542 }
543
544 if (should_stop)
545 break;
546
547 #ifdef CONFIG_AF_RXRPC_INJECT_RX_DELAY
548 skb = skb_peek(&local->rx_delay_queue);
549 if (skb) {
550 unsigned long timeout;
551 ktime_t tstamp = skb->tstamp;
552 ktime_t now = ktime_get_real();
553 s64 delay_ns = ktime_to_ns(ktime_sub(tstamp, now));
554
555 if (delay_ns <= 0) {
556 __set_current_state(TASK_RUNNING);
557 continue;
558 }
559
560 timeout = nsecs_to_jiffies(delay_ns);
561 timeout = max(timeout, 1UL);
562 schedule_timeout(timeout);
563 __set_current_state(TASK_RUNNING);
564 continue;
565 }
566 #endif
567
568 schedule();
569 }
570
571 __set_current_state(TASK_RUNNING);
572 rxrpc_see_local(local, rxrpc_local_stop);
573 rxrpc_destroy_local(local);
574 WRITE_ONCE(local->io_thread, NULL);
575 rxrpc_see_local(local, rxrpc_local_stopped);
576 return 0;
577 }
578
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