1 // SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause)
2 /* isotp.c - ISO 15765-2 CAN transport protocol for protocol family CAN
3 *
4 * This implementation does not provide ISO-TP specific return values to the
5 * userspace.
6 *
7 * - RX path timeout of data reception leads to -ETIMEDOUT
8 * - RX path SN mismatch leads to -EILSEQ
9 * - RX path data reception with wrong padding leads to -EBADMSG
10 * - TX path flowcontrol reception timeout leads to -ECOMM
11 * - TX path flowcontrol reception overflow leads to -EMSGSIZE
12 * - TX path flowcontrol reception with wrong layout/padding leads to -EBADMSG
13 * - when a transfer (tx) is on the run the next write() blocks until it's done
14 * - use CAN_ISOTP_WAIT_TX_DONE flag to block the caller until the PDU is sent
15 * - as we have static buffers the check whether the PDU fits into the buffer
16 * is done at FF reception time (no support for sending 'wait frames')
17 *
18 * Copyright (c) 2020 Volkswagen Group Electronic Research
19 * All rights reserved.
20 *
21 * Redistribution and use in source and binary forms, with or without
22 * modification, are permitted provided that the following conditions
23 * are met:
24 * 1. Redistributions of source code must retain the above copyright
25 * notice, this list of conditions and the following disclaimer.
26 * 2. Redistributions in binary form must reproduce the above copyright
27 * notice, this list of conditions and the following disclaimer in the
28 * documentation and/or other materials provided with the distribution.
29 * 3. Neither the name of Volkswagen nor the names of its contributors
30 * may be used to endorse or promote products derived from this software
31 * without specific prior written permission.
32 *
33 * Alternatively, provided that this notice is retained in full, this
34 * software may be distributed under the terms of the GNU General
35 * Public License ("GPL") version 2, in which case the provisions of the
36 * GPL apply INSTEAD OF those given above.
37 *
38 * The provided data structures and external interfaces from this code
39 * are not restricted to be used by modules with a GPL compatible license.
40 *
41 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
42 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
43 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
44 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
45 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
46 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
47 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
48 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
49 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
50 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
51 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
52 * DAMAGE.
53 */
54
55 #include <linux/module.h>
56 #include <linux/init.h>
57 #include <linux/interrupt.h>
58 #include <linux/spinlock.h>
59 #include <linux/hrtimer.h>
60 #include <linux/wait.h>
61 #include <linux/uio.h>
62 #include <linux/net.h>
63 #include <linux/netdevice.h>
64 #include <linux/socket.h>
65 #include <linux/if_arp.h>
66 #include <linux/skbuff.h>
67 #include <linux/can.h>
68 #include <linux/can/core.h>
69 #include <linux/can/skb.h>
70 #include <linux/can/isotp.h>
71 #include <linux/slab.h>
72 #include <net/sock.h>
73 #include <net/net_namespace.h>
74
75 MODULE_DESCRIPTION("PF_CAN ISO 15765-2 transport protocol");
76 MODULE_LICENSE("Dual BSD/GPL");
77 MODULE_AUTHOR("Oliver Hartkopp <socketcan@hartkopp.net>");
78 MODULE_ALIAS("can-proto-6");
79
80 #define ISOTP_MIN_NAMELEN CAN_REQUIRED_SIZE(struct sockaddr_can, can_addr.tp)
81
82 #define SINGLE_MASK(id) (((id) & CAN_EFF_FLAG) ? \
83 (CAN_EFF_MASK | CAN_EFF_FLAG | CAN_RTR_FLAG) : \
84 (CAN_SFF_MASK | CAN_EFF_FLAG | CAN_RTR_FLAG))
85
86 /* Since ISO 15765-2:2016 the CAN isotp protocol supports more than 4095
87 * byte per ISO PDU as the FF_DL can take full 32 bit values (4 Gbyte).
88 * We would need some good concept to handle this between user space and
89 * kernel space. For now set the static buffer to something about 8 kbyte
90 * to be able to test this new functionality.
91 */
92 #define DEFAULT_MAX_PDU_SIZE 8300
93
94 /* maximum PDU size before ISO 15765-2:2016 extension was 4095 */
95 #define MAX_12BIT_PDU_SIZE 4095
96
97 /* limit the isotp pdu size from the optional module parameter to 1MByte */
98 #define MAX_PDU_SIZE (1025 * 1024U)
99
100 static unsigned int max_pdu_size __read_mostly = DEFAULT_MAX_PDU_SIZE;
101 module_param(max_pdu_size, uint, 0444);
102 MODULE_PARM_DESC(max_pdu_size, "maximum isotp pdu size (default "
103 __stringify(DEFAULT_MAX_PDU_SIZE) ")");
104
105 /* N_PCI type values in bits 7-4 of N_PCI bytes */
106 #define N_PCI_SF 0x00 /* single frame */
107 #define N_PCI_FF 0x10 /* first frame */
108 #define N_PCI_CF 0x20 /* consecutive frame */
109 #define N_PCI_FC 0x30 /* flow control */
110
111 #define N_PCI_SZ 1 /* size of the PCI byte #1 */
112 #define SF_PCI_SZ4 1 /* size of SingleFrame PCI including 4 bit SF_DL */
113 #define SF_PCI_SZ8 2 /* size of SingleFrame PCI including 8 bit SF_DL */
114 #define FF_PCI_SZ12 2 /* size of FirstFrame PCI including 12 bit FF_DL */
115 #define FF_PCI_SZ32 6 /* size of FirstFrame PCI including 32 bit FF_DL */
116 #define FC_CONTENT_SZ 3 /* flow control content size in byte (FS/BS/STmin) */
117
118 #define ISOTP_CHECK_PADDING (CAN_ISOTP_CHK_PAD_LEN | CAN_ISOTP_CHK_PAD_DATA)
119 #define ISOTP_ALL_BC_FLAGS (CAN_ISOTP_SF_BROADCAST | CAN_ISOTP_CF_BROADCAST)
120
121 /* Flow Status given in FC frame */
122 #define ISOTP_FC_CTS 0 /* clear to send */
123 #define ISOTP_FC_WT 1 /* wait */
124 #define ISOTP_FC_OVFLW 2 /* overflow */
125
126 #define ISOTP_FC_TIMEOUT 1 /* 1 sec */
127 #define ISOTP_ECHO_TIMEOUT 2 /* 2 secs */
128
129 enum {
130 ISOTP_IDLE = 0,
131 ISOTP_WAIT_FIRST_FC,
132 ISOTP_WAIT_FC,
133 ISOTP_WAIT_DATA,
134 ISOTP_SENDING,
135 ISOTP_SHUTDOWN,
136 };
137
138 struct tpcon {
139 u8 *buf;
140 unsigned int buflen;
141 unsigned int len;
142 unsigned int idx;
143 u32 state;
144 u8 bs;
145 u8 sn;
146 u8 ll_dl;
147 u8 sbuf[DEFAULT_MAX_PDU_SIZE];
148 };
149
150 struct isotp_sock {
151 struct sock sk;
152 int bound;
153 int ifindex;
154 canid_t txid;
155 canid_t rxid;
156 ktime_t tx_gap;
157 ktime_t lastrxcf_tstamp;
158 struct hrtimer rxtimer, txtimer, txfrtimer;
159 struct can_isotp_options opt;
160 struct can_isotp_fc_options rxfc, txfc;
161 struct can_isotp_ll_options ll;
162 u32 frame_txtime;
163 u32 force_tx_stmin;
164 u32 force_rx_stmin;
165 u32 cfecho; /* consecutive frame echo tag */
166 struct tpcon rx, tx;
167 struct list_head notifier;
168 wait_queue_head_t wait;
169 spinlock_t rx_lock; /* protect single thread state machine */
170 };
171
172 static LIST_HEAD(isotp_notifier_list);
173 static DEFINE_SPINLOCK(isotp_notifier_lock);
174 static struct isotp_sock *isotp_busy_notifier;
175
176 static inline struct isotp_sock *isotp_sk(const struct sock *sk)
177 {
178 return (struct isotp_sock *)sk;
179 }
180
181 static u32 isotp_bc_flags(struct isotp_sock *so)
182 {
183 return so->opt.flags & ISOTP_ALL_BC_FLAGS;
184 }
185
186 static bool isotp_register_rxid(struct isotp_sock *so)
187 {
188 /* no broadcast modes => register rx_id for FC frame reception */
189 return (isotp_bc_flags(so) == 0);
190 }
191
192 static enum hrtimer_restart isotp_rx_timer_handler(struct hrtimer *hrtimer)
193 {
194 struct isotp_sock *so = container_of(hrtimer, struct isotp_sock,
195 rxtimer);
196 struct sock *sk = &so->sk;
197
198 if (so->rx.state == ISOTP_WAIT_DATA) {
199 /* we did not get new data frames in time */
200
201 /* report 'connection timed out' */
202 sk->sk_err = ETIMEDOUT;
203 if (!sock_flag(sk, SOCK_DEAD))
204 sk_error_report(sk);
205
206 /* reset rx state */
207 so->rx.state = ISOTP_IDLE;
208 }
209
210 return HRTIMER_NORESTART;
211 }
212
213 static int isotp_send_fc(struct sock *sk, int ae, u8 flowstatus)
214 {
215 struct net_device *dev;
216 struct sk_buff *nskb;
217 struct canfd_frame *ncf;
218 struct isotp_sock *so = isotp_sk(sk);
219 int can_send_ret;
220
221 nskb = alloc_skb(so->ll.mtu + sizeof(struct can_skb_priv), gfp_any());
222 if (!nskb)
223 return 1;
224
225 dev = dev_get_by_index(sock_net(sk), so->ifindex);
226 if (!dev) {
227 kfree_skb(nskb);
228 return 1;
229 }
230
231 can_skb_reserve(nskb);
232 can_skb_prv(nskb)->ifindex = dev->ifindex;
233 can_skb_prv(nskb)->skbcnt = 0;
234
235 nskb->dev = dev;
236 can_skb_set_owner(nskb, sk);
237 ncf = (struct canfd_frame *)nskb->data;
238 skb_put_zero(nskb, so->ll.mtu);
239
240 /* create & send flow control reply */
241 ncf->can_id = so->txid;
242
243 if (so->opt.flags & CAN_ISOTP_TX_PADDING) {
244 memset(ncf->data, so->opt.txpad_content, CAN_MAX_DLEN);
245 ncf->len = CAN_MAX_DLEN;
246 } else {
247 ncf->len = ae + FC_CONTENT_SZ;
248 }
249
250 ncf->data[ae] = N_PCI_FC | flowstatus;
251 ncf->data[ae + 1] = so->rxfc.bs;
252 ncf->data[ae + 2] = so->rxfc.stmin;
253
254 if (ae)
255 ncf->data[0] = so->opt.ext_address;
256
257 ncf->flags = so->ll.tx_flags;
258
259 can_send_ret = can_send(nskb, 1);
260 if (can_send_ret)
261 pr_notice_once("can-isotp: %s: can_send_ret %pe\n",
262 __func__, ERR_PTR(can_send_ret));
263
264 dev_put(dev);
265
266 /* reset blocksize counter */
267 so->rx.bs = 0;
268
269 /* reset last CF frame rx timestamp for rx stmin enforcement */
270 so->lastrxcf_tstamp = ktime_set(0, 0);
271
272 /* start rx timeout watchdog */
273 hrtimer_start(&so->rxtimer, ktime_set(ISOTP_FC_TIMEOUT, 0),
274 HRTIMER_MODE_REL_SOFT);
275 return 0;
276 }
277
278 static void isotp_rcv_skb(struct sk_buff *skb, struct sock *sk)
279 {
280 struct sockaddr_can *addr = (struct sockaddr_can *)skb->cb;
281
282 BUILD_BUG_ON(sizeof(skb->cb) < sizeof(struct sockaddr_can));
283
284 memset(addr, 0, sizeof(*addr));
285 addr->can_family = AF_CAN;
286 addr->can_ifindex = skb->dev->ifindex;
287
288 if (sock_queue_rcv_skb(sk, skb) < 0)
289 kfree_skb(skb);
290 }
291
292 static u8 padlen(u8 datalen)
293 {
294 static const u8 plen[] = {
295 8, 8, 8, 8, 8, 8, 8, 8, 8, /* 0 - 8 */
296 12, 12, 12, 12, /* 9 - 12 */
297 16, 16, 16, 16, /* 13 - 16 */
298 20, 20, 20, 20, /* 17 - 20 */
299 24, 24, 24, 24, /* 21 - 24 */
300 32, 32, 32, 32, 32, 32, 32, 32, /* 25 - 32 */
301 48, 48, 48, 48, 48, 48, 48, 48, /* 33 - 40 */
302 48, 48, 48, 48, 48, 48, 48, 48 /* 41 - 48 */
303 };
304
305 if (datalen > 48)
306 return 64;
307
308 return plen[datalen];
309 }
310
311 /* check for length optimization and return 1/true when the check fails */
312 static int check_optimized(struct canfd_frame *cf, int start_index)
313 {
314 /* for CAN_DL <= 8 the start_index is equal to the CAN_DL as the
315 * padding would start at this point. E.g. if the padding would
316 * start at cf.data[7] cf->len has to be 7 to be optimal.
317 * Note: The data[] index starts with zero.
318 */
319 if (cf->len <= CAN_MAX_DLEN)
320 return (cf->len != start_index);
321
322 /* This relation is also valid in the non-linear DLC range, where
323 * we need to take care of the minimal next possible CAN_DL.
324 * The correct check would be (padlen(cf->len) != padlen(start_index)).
325 * But as cf->len can only take discrete values from 12, .., 64 at this
326 * point the padlen(cf->len) is always equal to cf->len.
327 */
328 return (cf->len != padlen(start_index));
329 }
330
331 /* check padding and return 1/true when the check fails */
332 static int check_pad(struct isotp_sock *so, struct canfd_frame *cf,
333 int start_index, u8 content)
334 {
335 int i;
336
337 /* no RX_PADDING value => check length of optimized frame length */
338 if (!(so->opt.flags & CAN_ISOTP_RX_PADDING)) {
339 if (so->opt.flags & CAN_ISOTP_CHK_PAD_LEN)
340 return check_optimized(cf, start_index);
341
342 /* no valid test against empty value => ignore frame */
343 return 1;
344 }
345
346 /* check datalength of correctly padded CAN frame */
347 if ((so->opt.flags & CAN_ISOTP_CHK_PAD_LEN) &&
348 cf->len != padlen(cf->len))
349 return 1;
350
351 /* check padding content */
352 if (so->opt.flags & CAN_ISOTP_CHK_PAD_DATA) {
353 for (i = start_index; i < cf->len; i++)
354 if (cf->data[i] != content)
355 return 1;
356 }
357 return 0;
358 }
359
360 static void isotp_send_cframe(struct isotp_sock *so);
361
362 static int isotp_rcv_fc(struct isotp_sock *so, struct canfd_frame *cf, int ae)
363 {
364 struct sock *sk = &so->sk;
365
366 if (so->tx.state != ISOTP_WAIT_FC &&
367 so->tx.state != ISOTP_WAIT_FIRST_FC)
368 return 0;
369
370 hrtimer_cancel(&so->txtimer);
371
372 if ((cf->len < ae + FC_CONTENT_SZ) ||
373 ((so->opt.flags & ISOTP_CHECK_PADDING) &&
374 check_pad(so, cf, ae + FC_CONTENT_SZ, so->opt.rxpad_content))) {
375 /* malformed PDU - report 'not a data message' */
376 sk->sk_err = EBADMSG;
377 if (!sock_flag(sk, SOCK_DEAD))
378 sk_error_report(sk);
379
380 so->tx.state = ISOTP_IDLE;
381 wake_up_interruptible(&so->wait);
382 return 1;
383 }
384
385 /* get static/dynamic communication params from first/every FC frame */
386 if (so->tx.state == ISOTP_WAIT_FIRST_FC ||
387 so->opt.flags & CAN_ISOTP_DYN_FC_PARMS) {
388 so->txfc.bs = cf->data[ae + 1];
389 so->txfc.stmin = cf->data[ae + 2];
390
391 /* fix wrong STmin values according spec */
392 if (so->txfc.stmin > 0x7F &&
393 (so->txfc.stmin < 0xF1 || so->txfc.stmin > 0xF9))
394 so->txfc.stmin = 0x7F;
395
396 so->tx_gap = ktime_set(0, 0);
397 /* add transmission time for CAN frame N_As */
398 so->tx_gap = ktime_add_ns(so->tx_gap, so->frame_txtime);
399 /* add waiting time for consecutive frames N_Cs */
400 if (so->opt.flags & CAN_ISOTP_FORCE_TXSTMIN)
401 so->tx_gap = ktime_add_ns(so->tx_gap,
402 so->force_tx_stmin);
403 else if (so->txfc.stmin < 0x80)
404 so->tx_gap = ktime_add_ns(so->tx_gap,
405 so->txfc.stmin * 1000000);
406 else
407 so->tx_gap = ktime_add_ns(so->tx_gap,
408 (so->txfc.stmin - 0xF0)
409 * 100000);
410 so->tx.state = ISOTP_WAIT_FC;
411 }
412
413 switch (cf->data[ae] & 0x0F) {
414 case ISOTP_FC_CTS:
415 so->tx.bs = 0;
416 so->tx.state = ISOTP_SENDING;
417 /* send CF frame and enable echo timeout handling */
418 hrtimer_start(&so->txtimer, ktime_set(ISOTP_ECHO_TIMEOUT, 0),
419 HRTIMER_MODE_REL_SOFT);
420 isotp_send_cframe(so);
421 break;
422
423 case ISOTP_FC_WT:
424 /* start timer to wait for next FC frame */
425 hrtimer_start(&so->txtimer, ktime_set(ISOTP_FC_TIMEOUT, 0),
426 HRTIMER_MODE_REL_SOFT);
427 break;
428
429 case ISOTP_FC_OVFLW:
430 /* overflow on receiver side - report 'message too long' */
431 sk->sk_err = EMSGSIZE;
432 if (!sock_flag(sk, SOCK_DEAD))
433 sk_error_report(sk);
434 fallthrough;
435
436 default:
437 /* stop this tx job */
438 so->tx.state = ISOTP_IDLE;
439 wake_up_interruptible(&so->wait);
440 }
441 return 0;
442 }
443
444 static int isotp_rcv_sf(struct sock *sk, struct canfd_frame *cf, int pcilen,
445 struct sk_buff *skb, int len)
446 {
447 struct isotp_sock *so = isotp_sk(sk);
448 struct sk_buff *nskb;
449
450 hrtimer_cancel(&so->rxtimer);
451 so->rx.state = ISOTP_IDLE;
452
453 if (!len || len > cf->len - pcilen)
454 return 1;
455
456 if ((so->opt.flags & ISOTP_CHECK_PADDING) &&
457 check_pad(so, cf, pcilen + len, so->opt.rxpad_content)) {
458 /* malformed PDU - report 'not a data message' */
459 sk->sk_err = EBADMSG;
460 if (!sock_flag(sk, SOCK_DEAD))
461 sk_error_report(sk);
462 return 1;
463 }
464
465 nskb = alloc_skb(len, gfp_any());
466 if (!nskb)
467 return 1;
468
469 memcpy(skb_put(nskb, len), &cf->data[pcilen], len);
470
471 nskb->tstamp = skb->tstamp;
472 nskb->dev = skb->dev;
473 isotp_rcv_skb(nskb, sk);
474 return 0;
475 }
476
477 static int isotp_rcv_ff(struct sock *sk, struct canfd_frame *cf, int ae)
478 {
479 struct isotp_sock *so = isotp_sk(sk);
480 int i;
481 int off;
482 int ff_pci_sz;
483
484 hrtimer_cancel(&so->rxtimer);
485 so->rx.state = ISOTP_IDLE;
486
487 /* get the used sender LL_DL from the (first) CAN frame data length */
488 so->rx.ll_dl = padlen(cf->len);
489
490 /* the first frame has to use the entire frame up to LL_DL length */
491 if (cf->len != so->rx.ll_dl)
492 return 1;
493
494 /* get the FF_DL */
495 so->rx.len = (cf->data[ae] & 0x0F) << 8;
496 so->rx.len += cf->data[ae + 1];
497
498 /* Check for FF_DL escape sequence supporting 32 bit PDU length */
499 if (so->rx.len) {
500 ff_pci_sz = FF_PCI_SZ12;
501 } else {
502 /* FF_DL = 0 => get real length from next 4 bytes */
503 so->rx.len = cf->data[ae + 2] << 24;
504 so->rx.len += cf->data[ae + 3] << 16;
505 so->rx.len += cf->data[ae + 4] << 8;
506 so->rx.len += cf->data[ae + 5];
507 ff_pci_sz = FF_PCI_SZ32;
508 }
509
510 /* take care of a potential SF_DL ESC offset for TX_DL > 8 */
511 off = (so->rx.ll_dl > CAN_MAX_DLEN) ? 1 : 0;
512
513 if (so->rx.len + ae + off + ff_pci_sz < so->rx.ll_dl)
514 return 1;
515
516 /* PDU size > default => try max_pdu_size */
517 if (so->rx.len > so->rx.buflen && so->rx.buflen < max_pdu_size) {
518 u8 *newbuf = kmalloc(max_pdu_size, GFP_ATOMIC);
519
520 if (newbuf) {
521 so->rx.buf = newbuf;
522 so->rx.buflen = max_pdu_size;
523 }
524 }
525
526 if (so->rx.len > so->rx.buflen) {
527 /* send FC frame with overflow status */
528 isotp_send_fc(sk, ae, ISOTP_FC_OVFLW);
529 return 1;
530 }
531
532 /* copy the first received data bytes */
533 so->rx.idx = 0;
534 for (i = ae + ff_pci_sz; i < so->rx.ll_dl; i++)
535 so->rx.buf[so->rx.idx++] = cf->data[i];
536
537 /* initial setup for this pdu reception */
538 so->rx.sn = 1;
539 so->rx.state = ISOTP_WAIT_DATA;
540
541 /* no creation of flow control frames */
542 if (so->opt.flags & CAN_ISOTP_LISTEN_MODE)
543 return 0;
544
545 /* send our first FC frame */
546 isotp_send_fc(sk, ae, ISOTP_FC_CTS);
547 return 0;
548 }
549
550 static int isotp_rcv_cf(struct sock *sk, struct canfd_frame *cf, int ae,
551 struct sk_buff *skb)
552 {
553 struct isotp_sock *so = isotp_sk(sk);
554 struct sk_buff *nskb;
555 int i;
556
557 if (so->rx.state != ISOTP_WAIT_DATA)
558 return 0;
559
560 /* drop if timestamp gap is less than force_rx_stmin nano secs */
561 if (so->opt.flags & CAN_ISOTP_FORCE_RXSTMIN) {
562 if (ktime_to_ns(ktime_sub(skb->tstamp, so->lastrxcf_tstamp)) <
563 so->force_rx_stmin)
564 return 0;
565
566 so->lastrxcf_tstamp = skb->tstamp;
567 }
568
569 hrtimer_cancel(&so->rxtimer);
570
571 /* CFs are never longer than the FF */
572 if (cf->len > so->rx.ll_dl)
573 return 1;
574
575 /* CFs have usually the LL_DL length */
576 if (cf->len < so->rx.ll_dl) {
577 /* this is only allowed for the last CF */
578 if (so->rx.len - so->rx.idx > so->rx.ll_dl - ae - N_PCI_SZ)
579 return 1;
580 }
581
582 if ((cf->data[ae] & 0x0F) != so->rx.sn) {
583 /* wrong sn detected - report 'illegal byte sequence' */
584 sk->sk_err = EILSEQ;
585 if (!sock_flag(sk, SOCK_DEAD))
586 sk_error_report(sk);
587
588 /* reset rx state */
589 so->rx.state = ISOTP_IDLE;
590 return 1;
591 }
592 so->rx.sn++;
593 so->rx.sn %= 16;
594
595 for (i = ae + N_PCI_SZ; i < cf->len; i++) {
596 so->rx.buf[so->rx.idx++] = cf->data[i];
597 if (so->rx.idx >= so->rx.len)
598 break;
599 }
600
601 if (so->rx.idx >= so->rx.len) {
602 /* we are done */
603 so->rx.state = ISOTP_IDLE;
604
605 if ((so->opt.flags & ISOTP_CHECK_PADDING) &&
606 check_pad(so, cf, i + 1, so->opt.rxpad_content)) {
607 /* malformed PDU - report 'not a data message' */
608 sk->sk_err = EBADMSG;
609 if (!sock_flag(sk, SOCK_DEAD))
610 sk_error_report(sk);
611 return 1;
612 }
613
614 nskb = alloc_skb(so->rx.len, gfp_any());
615 if (!nskb)
616 return 1;
617
618 memcpy(skb_put(nskb, so->rx.len), so->rx.buf,
619 so->rx.len);
620
621 nskb->tstamp = skb->tstamp;
622 nskb->dev = skb->dev;
623 isotp_rcv_skb(nskb, sk);
624 return 0;
625 }
626
627 /* perform blocksize handling, if enabled */
628 if (!so->rxfc.bs || ++so->rx.bs < so->rxfc.bs) {
629 /* start rx timeout watchdog */
630 hrtimer_start(&so->rxtimer, ktime_set(ISOTP_FC_TIMEOUT, 0),
631 HRTIMER_MODE_REL_SOFT);
632 return 0;
633 }
634
635 /* no creation of flow control frames */
636 if (so->opt.flags & CAN_ISOTP_LISTEN_MODE)
637 return 0;
638
639 /* we reached the specified blocksize so->rxfc.bs */
640 isotp_send_fc(sk, ae, ISOTP_FC_CTS);
641 return 0;
642 }
643
644 static void isotp_rcv(struct sk_buff *skb, void *data)
645 {
646 struct sock *sk = (struct sock *)data;
647 struct isotp_sock *so = isotp_sk(sk);
648 struct canfd_frame *cf;
649 int ae = (so->opt.flags & CAN_ISOTP_EXTEND_ADDR) ? 1 : 0;
650 u8 n_pci_type, sf_dl;
651
652 /* Strictly receive only frames with the configured MTU size
653 * => clear separation of CAN2.0 / CAN FD transport channels
654 */
655 if (skb->len != so->ll.mtu)
656 return;
657
658 cf = (struct canfd_frame *)skb->data;
659
660 /* if enabled: check reception of my configured extended address */
661 if (ae && cf->data[0] != so->opt.rx_ext_address)
662 return;
663
664 n_pci_type = cf->data[ae] & 0xF0;
665
666 /* Make sure the state changes and data structures stay consistent at
667 * CAN frame reception time. This locking is not needed in real world
668 * use cases but the inconsistency can be triggered with syzkaller.
669 */
670 spin_lock(&so->rx_lock);
671
672 if (so->opt.flags & CAN_ISOTP_HALF_DUPLEX) {
673 /* check rx/tx path half duplex expectations */
674 if ((so->tx.state != ISOTP_IDLE && n_pci_type != N_PCI_FC) ||
675 (so->rx.state != ISOTP_IDLE && n_pci_type == N_PCI_FC))
676 goto out_unlock;
677 }
678
679 switch (n_pci_type) {
680 case N_PCI_FC:
681 /* tx path: flow control frame containing the FC parameters */
682 isotp_rcv_fc(so, cf, ae);
683 break;
684
685 case N_PCI_SF:
686 /* rx path: single frame
687 *
688 * As we do not have a rx.ll_dl configuration, we can only test
689 * if the CAN frames payload length matches the LL_DL == 8
690 * requirements - no matter if it's CAN 2.0 or CAN FD
691 */
692
693 /* get the SF_DL from the N_PCI byte */
694 sf_dl = cf->data[ae] & 0x0F;
695
696 if (cf->len <= CAN_MAX_DLEN) {
697 isotp_rcv_sf(sk, cf, SF_PCI_SZ4 + ae, skb, sf_dl);
698 } else {
699 if (can_is_canfd_skb(skb)) {
700 /* We have a CAN FD frame and CAN_DL is greater than 8:
701 * Only frames with the SF_DL == 0 ESC value are valid.
702 *
703 * If so take care of the increased SF PCI size
704 * (SF_PCI_SZ8) to point to the message content behind
705 * the extended SF PCI info and get the real SF_DL
706 * length value from the formerly first data byte.
707 */
708 if (sf_dl == 0)
709 isotp_rcv_sf(sk, cf, SF_PCI_SZ8 + ae, skb,
710 cf->data[SF_PCI_SZ4 + ae]);
711 }
712 }
713 break;
714
715 case N_PCI_FF:
716 /* rx path: first frame */
717 isotp_rcv_ff(sk, cf, ae);
718 break;
719
720 case N_PCI_CF:
721 /* rx path: consecutive frame */
722 isotp_rcv_cf(sk, cf, ae, skb);
723 break;
724 }
725
726 out_unlock:
727 spin_unlock(&so->rx_lock);
728 }
729
730 static void isotp_fill_dataframe(struct canfd_frame *cf, struct isotp_sock *so,
731 int ae, int off)
732 {
733 int pcilen = N_PCI_SZ + ae + off;
734 int space = so->tx.ll_dl - pcilen;
735 int num = min_t(int, so->tx.len - so->tx.idx, space);
736 int i;
737
738 cf->can_id = so->txid;
739 cf->len = num + pcilen;
740
741 if (num < space) {
742 if (so->opt.flags & CAN_ISOTP_TX_PADDING) {
743 /* user requested padding */
744 cf->len = padlen(cf->len);
745 memset(cf->data, so->opt.txpad_content, cf->len);
746 } else if (cf->len > CAN_MAX_DLEN) {
747 /* mandatory padding for CAN FD frames */
748 cf->len = padlen(cf->len);
749 memset(cf->data, CAN_ISOTP_DEFAULT_PAD_CONTENT,
750 cf->len);
751 }
752 }
753
754 for (i = 0; i < num; i++)
755 cf->data[pcilen + i] = so->tx.buf[so->tx.idx++];
756
757 if (ae)
758 cf->data[0] = so->opt.ext_address;
759 }
760
761 static void isotp_send_cframe(struct isotp_sock *so)
762 {
763 struct sock *sk = &so->sk;
764 struct sk_buff *skb;
765 struct net_device *dev;
766 struct canfd_frame *cf;
767 int can_send_ret;
768 int ae = (so->opt.flags & CAN_ISOTP_EXTEND_ADDR) ? 1 : 0;
769
770 dev = dev_get_by_index(sock_net(sk), so->ifindex);
771 if (!dev)
772 return;
773
774 skb = alloc_skb(so->ll.mtu + sizeof(struct can_skb_priv), GFP_ATOMIC);
775 if (!skb) {
776 dev_put(dev);
777 return;
778 }
779
780 can_skb_reserve(skb);
781 can_skb_prv(skb)->ifindex = dev->ifindex;
782 can_skb_prv(skb)->skbcnt = 0;
783
784 cf = (struct canfd_frame *)skb->data;
785 skb_put_zero(skb, so->ll.mtu);
786
787 /* create consecutive frame */
788 isotp_fill_dataframe(cf, so, ae, 0);
789
790 /* place consecutive frame N_PCI in appropriate index */
791 cf->data[ae] = N_PCI_CF | so->tx.sn++;
792 so->tx.sn %= 16;
793 so->tx.bs++;
794
795 cf->flags = so->ll.tx_flags;
796
797 skb->dev = dev;
798 can_skb_set_owner(skb, sk);
799
800 /* cfecho should have been zero'ed by init/isotp_rcv_echo() */
801 if (so->cfecho)
802 pr_notice_once("can-isotp: cfecho is %08X != 0\n", so->cfecho);
803
804 /* set consecutive frame echo tag */
805 so->cfecho = *(u32 *)cf->data;
806
807 /* send frame with local echo enabled */
808 can_send_ret = can_send(skb, 1);
809 if (can_send_ret) {
810 pr_notice_once("can-isotp: %s: can_send_ret %pe\n",
811 __func__, ERR_PTR(can_send_ret));
812 if (can_send_ret == -ENOBUFS)
813 pr_notice_once("can-isotp: tx queue is full\n");
814 }
815 dev_put(dev);
816 }
817
818 static void isotp_create_fframe(struct canfd_frame *cf, struct isotp_sock *so,
819 int ae)
820 {
821 int i;
822 int ff_pci_sz;
823
824 cf->can_id = so->txid;
825 cf->len = so->tx.ll_dl;
826 if (ae)
827 cf->data[0] = so->opt.ext_address;
828
829 /* create N_PCI bytes with 12/32 bit FF_DL data length */
830 if (so->tx.len > MAX_12BIT_PDU_SIZE) {
831 /* use 32 bit FF_DL notation */
832 cf->data[ae] = N_PCI_FF;
833 cf->data[ae + 1] = 0;
834 cf->data[ae + 2] = (u8)(so->tx.len >> 24) & 0xFFU;
835 cf->data[ae + 3] = (u8)(so->tx.len >> 16) & 0xFFU;
836 cf->data[ae + 4] = (u8)(so->tx.len >> 8) & 0xFFU;
837 cf->data[ae + 5] = (u8)so->tx.len & 0xFFU;
838 ff_pci_sz = FF_PCI_SZ32;
839 } else {
840 /* use 12 bit FF_DL notation */
841 cf->data[ae] = (u8)(so->tx.len >> 8) | N_PCI_FF;
842 cf->data[ae + 1] = (u8)so->tx.len & 0xFFU;
843 ff_pci_sz = FF_PCI_SZ12;
844 }
845
846 /* add first data bytes depending on ae */
847 for (i = ae + ff_pci_sz; i < so->tx.ll_dl; i++)
848 cf->data[i] = so->tx.buf[so->tx.idx++];
849
850 so->tx.sn = 1;
851 }
852
853 static void isotp_rcv_echo(struct sk_buff *skb, void *data)
854 {
855 struct sock *sk = (struct sock *)data;
856 struct isotp_sock *so = isotp_sk(sk);
857 struct canfd_frame *cf = (struct canfd_frame *)skb->data;
858
859 /* only handle my own local echo CF/SF skb's (no FF!) */
860 if (skb->sk != sk || so->cfecho != *(u32 *)cf->data)
861 return;
862
863 /* cancel local echo timeout */
864 hrtimer_cancel(&so->txtimer);
865
866 /* local echo skb with consecutive frame has been consumed */
867 so->cfecho = 0;
868
869 if (so->tx.idx >= so->tx.len) {
870 /* we are done */
871 so->tx.state = ISOTP_IDLE;
872 wake_up_interruptible(&so->wait);
873 return;
874 }
875
876 if (so->txfc.bs && so->tx.bs >= so->txfc.bs) {
877 /* stop and wait for FC with timeout */
878 so->tx.state = ISOTP_WAIT_FC;
879 hrtimer_start(&so->txtimer, ktime_set(ISOTP_FC_TIMEOUT, 0),
880 HRTIMER_MODE_REL_SOFT);
881 return;
882 }
883
884 /* no gap between data frames needed => use burst mode */
885 if (!so->tx_gap) {
886 /* enable echo timeout handling */
887 hrtimer_start(&so->txtimer, ktime_set(ISOTP_ECHO_TIMEOUT, 0),
888 HRTIMER_MODE_REL_SOFT);
889 isotp_send_cframe(so);
890 return;
891 }
892
893 /* start timer to send next consecutive frame with correct delay */
894 hrtimer_start(&so->txfrtimer, so->tx_gap, HRTIMER_MODE_REL_SOFT);
895 }
896
897 static enum hrtimer_restart isotp_tx_timer_handler(struct hrtimer *hrtimer)
898 {
899 struct isotp_sock *so = container_of(hrtimer, struct isotp_sock,
900 txtimer);
901 struct sock *sk = &so->sk;
902
903 /* don't handle timeouts in IDLE or SHUTDOWN state */
904 if (so->tx.state == ISOTP_IDLE || so->tx.state == ISOTP_SHUTDOWN)
905 return HRTIMER_NORESTART;
906
907 /* we did not get any flow control or echo frame in time */
908
909 /* report 'communication error on send' */
910 sk->sk_err = ECOMM;
911 if (!sock_flag(sk, SOCK_DEAD))
912 sk_error_report(sk);
913
914 /* reset tx state */
915 so->tx.state = ISOTP_IDLE;
916 wake_up_interruptible(&so->wait);
917
918 return HRTIMER_NORESTART;
919 }
920
921 static enum hrtimer_restart isotp_txfr_timer_handler(struct hrtimer *hrtimer)
922 {
923 struct isotp_sock *so = container_of(hrtimer, struct isotp_sock,
924 txfrtimer);
925
926 /* start echo timeout handling and cover below protocol error */
927 hrtimer_start(&so->txtimer, ktime_set(ISOTP_ECHO_TIMEOUT, 0),
928 HRTIMER_MODE_REL_SOFT);
929
930 /* cfecho should be consumed by isotp_rcv_echo() here */
931 if (so->tx.state == ISOTP_SENDING && !so->cfecho)
932 isotp_send_cframe(so);
933
934 return HRTIMER_NORESTART;
935 }
936
937 static int isotp_sendmsg(struct socket *sock, struct msghdr *msg, size_t size)
938 {
939 struct sock *sk = sock->sk;
940 struct isotp_sock *so = isotp_sk(sk);
941 struct sk_buff *skb;
942 struct net_device *dev;
943 struct canfd_frame *cf;
944 int ae = (so->opt.flags & CAN_ISOTP_EXTEND_ADDR) ? 1 : 0;
945 int wait_tx_done = (so->opt.flags & CAN_ISOTP_WAIT_TX_DONE) ? 1 : 0;
946 s64 hrtimer_sec = ISOTP_ECHO_TIMEOUT;
947 int off;
948 int err;
949
950 if (!so->bound || so->tx.state == ISOTP_SHUTDOWN)
951 return -EADDRNOTAVAIL;
952
953 while (cmpxchg(&so->tx.state, ISOTP_IDLE, ISOTP_SENDING) != ISOTP_IDLE) {
954 /* we do not support multiple buffers - for now */
955 if (msg->msg_flags & MSG_DONTWAIT)
956 return -EAGAIN;
957
958 if (so->tx.state == ISOTP_SHUTDOWN)
959 return -EADDRNOTAVAIL;
960
961 /* wait for complete transmission of current pdu */
962 err = wait_event_interruptible(so->wait, so->tx.state == ISOTP_IDLE);
963 if (err)
964 goto err_event_drop;
965 }
966
967 /* PDU size > default => try max_pdu_size */
968 if (size > so->tx.buflen && so->tx.buflen < max_pdu_size) {
969 u8 *newbuf = kmalloc(max_pdu_size, GFP_KERNEL);
970
971 if (newbuf) {
972 so->tx.buf = newbuf;
973 so->tx.buflen = max_pdu_size;
974 }
975 }
976
977 if (!size || size > so->tx.buflen) {
978 err = -EINVAL;
979 goto err_out_drop;
980 }
981
982 /* take care of a potential SF_DL ESC offset for TX_DL > 8 */
983 off = (so->tx.ll_dl > CAN_MAX_DLEN) ? 1 : 0;
984
985 /* does the given data fit into a single frame for SF_BROADCAST? */
986 if ((isotp_bc_flags(so) == CAN_ISOTP_SF_BROADCAST) &&
987 (size > so->tx.ll_dl - SF_PCI_SZ4 - ae - off)) {
988 err = -EINVAL;
989 goto err_out_drop;
990 }
991
992 err = memcpy_from_msg(so->tx.buf, msg, size);
993 if (err < 0)
994 goto err_out_drop;
995
996 dev = dev_get_by_index(sock_net(sk), so->ifindex);
997 if (!dev) {
998 err = -ENXIO;
999 goto err_out_drop;
1000 }
1001
1002 skb = sock_alloc_send_skb(sk, so->ll.mtu + sizeof(struct can_skb_priv),
1003 msg->msg_flags & MSG_DONTWAIT, &err);
1004 if (!skb) {
1005 dev_put(dev);
1006 goto err_out_drop;
1007 }
1008
1009 can_skb_reserve(skb);
1010 can_skb_prv(skb)->ifindex = dev->ifindex;
1011 can_skb_prv(skb)->skbcnt = 0;
1012
1013 so->tx.len = size;
1014 so->tx.idx = 0;
1015
1016 cf = (struct canfd_frame *)skb->data;
1017 skb_put_zero(skb, so->ll.mtu);
1018
1019 /* cfecho should have been zero'ed by init / former isotp_rcv_echo() */
1020 if (so->cfecho)
1021 pr_notice_once("can-isotp: uninit cfecho %08X\n", so->cfecho);
1022
1023 /* check for single frame transmission depending on TX_DL */
1024 if (size <= so->tx.ll_dl - SF_PCI_SZ4 - ae - off) {
1025 /* The message size generally fits into a SingleFrame - good.
1026 *
1027 * SF_DL ESC offset optimization:
1028 *
1029 * When TX_DL is greater 8 but the message would still fit
1030 * into a 8 byte CAN frame, we can omit the offset.
1031 * This prevents a protocol caused length extension from
1032 * CAN_DL = 8 to CAN_DL = 12 due to the SF_SL ESC handling.
1033 */
1034 if (size <= CAN_MAX_DLEN - SF_PCI_SZ4 - ae)
1035 off = 0;
1036
1037 isotp_fill_dataframe(cf, so, ae, off);
1038
1039 /* place single frame N_PCI w/o length in appropriate index */
1040 cf->data[ae] = N_PCI_SF;
1041
1042 /* place SF_DL size value depending on the SF_DL ESC offset */
1043 if (off)
1044 cf->data[SF_PCI_SZ4 + ae] = size;
1045 else
1046 cf->data[ae] |= size;
1047
1048 /* set CF echo tag for isotp_rcv_echo() (SF-mode) */
1049 so->cfecho = *(u32 *)cf->data;
1050 } else {
1051 /* send first frame */
1052
1053 isotp_create_fframe(cf, so, ae);
1054
1055 if (isotp_bc_flags(so) == CAN_ISOTP_CF_BROADCAST) {
1056 /* set timer for FC-less operation (STmin = 0) */
1057 if (so->opt.flags & CAN_ISOTP_FORCE_TXSTMIN)
1058 so->tx_gap = ktime_set(0, so->force_tx_stmin);
1059 else
1060 so->tx_gap = ktime_set(0, so->frame_txtime);
1061
1062 /* disable wait for FCs due to activated block size */
1063 so->txfc.bs = 0;
1064
1065 /* set CF echo tag for isotp_rcv_echo() (CF-mode) */
1066 so->cfecho = *(u32 *)cf->data;
1067 } else {
1068 /* standard flow control check */
1069 so->tx.state = ISOTP_WAIT_FIRST_FC;
1070
1071 /* start timeout for FC */
1072 hrtimer_sec = ISOTP_FC_TIMEOUT;
1073
1074 /* no CF echo tag for isotp_rcv_echo() (FF-mode) */
1075 so->cfecho = 0;
1076 }
1077 }
1078
1079 hrtimer_start(&so->txtimer, ktime_set(hrtimer_sec, 0),
1080 HRTIMER_MODE_REL_SOFT);
1081
1082 /* send the first or only CAN frame */
1083 cf->flags = so->ll.tx_flags;
1084
1085 skb->dev = dev;
1086 skb->sk = sk;
1087 err = can_send(skb, 1);
1088 dev_put(dev);
1089 if (err) {
1090 pr_notice_once("can-isotp: %s: can_send_ret %pe\n",
1091 __func__, ERR_PTR(err));
1092
1093 /* no transmission -> no timeout monitoring */
1094 hrtimer_cancel(&so->txtimer);
1095
1096 /* reset consecutive frame echo tag */
1097 so->cfecho = 0;
1098
1099 goto err_out_drop;
1100 }
1101
1102 if (wait_tx_done) {
1103 /* wait for complete transmission of current pdu */
1104 err = wait_event_interruptible(so->wait, so->tx.state == ISOTP_IDLE);
1105 if (err)
1106 goto err_event_drop;
1107
1108 err = sock_error(sk);
1109 if (err)
1110 return err;
1111 }
1112
1113 return size;
1114
1115 err_event_drop:
1116 /* got signal: force tx state machine to be idle */
1117 so->tx.state = ISOTP_IDLE;
1118 hrtimer_cancel(&so->txfrtimer);
1119 hrtimer_cancel(&so->txtimer);
1120 err_out_drop:
1121 /* drop this PDU and unlock a potential wait queue */
1122 so->tx.state = ISOTP_IDLE;
1123 wake_up_interruptible(&so->wait);
1124
1125 return err;
1126 }
1127
1128 static int isotp_recvmsg(struct socket *sock, struct msghdr *msg, size_t size,
1129 int flags)
1130 {
1131 struct sock *sk = sock->sk;
1132 struct sk_buff *skb;
1133 struct isotp_sock *so = isotp_sk(sk);
1134 int ret = 0;
1135
1136 if (flags & ~(MSG_DONTWAIT | MSG_TRUNC | MSG_PEEK | MSG_CMSG_COMPAT))
1137 return -EINVAL;
1138
1139 if (!so->bound)
1140 return -EADDRNOTAVAIL;
1141
1142 skb = skb_recv_datagram(sk, flags, &ret);
1143 if (!skb)
1144 return ret;
1145
1146 if (size < skb->len)
1147 msg->msg_flags |= MSG_TRUNC;
1148 else
1149 size = skb->len;
1150
1151 ret = memcpy_to_msg(msg, skb->data, size);
1152 if (ret < 0)
1153 goto out_err;
1154
1155 sock_recv_cmsgs(msg, sk, skb);
1156
1157 if (msg->msg_name) {
1158 __sockaddr_check_size(ISOTP_MIN_NAMELEN);
1159 msg->msg_namelen = ISOTP_MIN_NAMELEN;
1160 memcpy(msg->msg_name, skb->cb, msg->msg_namelen);
1161 }
1162
1163 /* set length of return value */
1164 ret = (flags & MSG_TRUNC) ? skb->len : size;
1165
1166 out_err:
1167 skb_free_datagram(sk, skb);
1168
1169 return ret;
1170 }
1171
1172 static int isotp_release(struct socket *sock)
1173 {
1174 struct sock *sk = sock->sk;
1175 struct isotp_sock *so;
1176 struct net *net;
1177
1178 if (!sk)
1179 return 0;
1180
1181 so = isotp_sk(sk);
1182 net = sock_net(sk);
1183
1184 /* wait for complete transmission of current pdu */
1185 while (wait_event_interruptible(so->wait, so->tx.state == ISOTP_IDLE) == 0 &&
1186 cmpxchg(&so->tx.state, ISOTP_IDLE, ISOTP_SHUTDOWN) != ISOTP_IDLE)
1187 ;
1188
1189 /* force state machines to be idle also when a signal occurred */
1190 so->tx.state = ISOTP_SHUTDOWN;
1191 so->rx.state = ISOTP_IDLE;
1192
1193 spin_lock(&isotp_notifier_lock);
1194 while (isotp_busy_notifier == so) {
1195 spin_unlock(&isotp_notifier_lock);
1196 schedule_timeout_uninterruptible(1);
1197 spin_lock(&isotp_notifier_lock);
1198 }
1199 list_del(&so->notifier);
1200 spin_unlock(&isotp_notifier_lock);
1201
1202 lock_sock(sk);
1203
1204 /* remove current filters & unregister */
1205 if (so->bound) {
1206 if (so->ifindex) {
1207 struct net_device *dev;
1208
1209 dev = dev_get_by_index(net, so->ifindex);
1210 if (dev) {
1211 if (isotp_register_rxid(so))
1212 can_rx_unregister(net, dev, so->rxid,
1213 SINGLE_MASK(so->rxid),
1214 isotp_rcv, sk);
1215
1216 can_rx_unregister(net, dev, so->txid,
1217 SINGLE_MASK(so->txid),
1218 isotp_rcv_echo, sk);
1219 dev_put(dev);
1220 synchronize_rcu();
1221 }
1222 }
1223 }
1224
1225 hrtimer_cancel(&so->txfrtimer);
1226 hrtimer_cancel(&so->txtimer);
1227 hrtimer_cancel(&so->rxtimer);
1228
1229 so->ifindex = 0;
1230 so->bound = 0;
1231
1232 if (so->rx.buf != so->rx.sbuf)
1233 kfree(so->rx.buf);
1234
1235 if (so->tx.buf != so->tx.sbuf)
1236 kfree(so->tx.buf);
1237
1238 sock_orphan(sk);
1239 sock->sk = NULL;
1240
1241 release_sock(sk);
1242 sock_put(sk);
1243
1244 return 0;
1245 }
1246
1247 static int isotp_bind(struct socket *sock, struct sockaddr *uaddr, int len)
1248 {
1249 struct sockaddr_can *addr = (struct sockaddr_can *)uaddr;
1250 struct sock *sk = sock->sk;
1251 struct isotp_sock *so = isotp_sk(sk);
1252 struct net *net = sock_net(sk);
1253 int ifindex;
1254 struct net_device *dev;
1255 canid_t tx_id = addr->can_addr.tp.tx_id;
1256 canid_t rx_id = addr->can_addr.tp.rx_id;
1257 int err = 0;
1258 int notify_enetdown = 0;
1259
1260 if (len < ISOTP_MIN_NAMELEN)
1261 return -EINVAL;
1262
1263 if (addr->can_family != AF_CAN)
1264 return -EINVAL;
1265
1266 /* sanitize tx CAN identifier */
1267 if (tx_id & CAN_EFF_FLAG)
1268 tx_id &= (CAN_EFF_FLAG | CAN_EFF_MASK);
1269 else
1270 tx_id &= CAN_SFF_MASK;
1271
1272 /* give feedback on wrong CAN-ID value */
1273 if (tx_id != addr->can_addr.tp.tx_id)
1274 return -EINVAL;
1275
1276 /* sanitize rx CAN identifier (if needed) */
1277 if (isotp_register_rxid(so)) {
1278 if (rx_id & CAN_EFF_FLAG)
1279 rx_id &= (CAN_EFF_FLAG | CAN_EFF_MASK);
1280 else
1281 rx_id &= CAN_SFF_MASK;
1282
1283 /* give feedback on wrong CAN-ID value */
1284 if (rx_id != addr->can_addr.tp.rx_id)
1285 return -EINVAL;
1286 }
1287
1288 if (!addr->can_ifindex)
1289 return -ENODEV;
1290
1291 lock_sock(sk);
1292
1293 if (so->bound) {
1294 err = -EINVAL;
1295 goto out;
1296 }
1297
1298 /* ensure different CAN IDs when the rx_id is to be registered */
1299 if (isotp_register_rxid(so) && rx_id == tx_id) {
1300 err = -EADDRNOTAVAIL;
1301 goto out;
1302 }
1303
1304 dev = dev_get_by_index(net, addr->can_ifindex);
1305 if (!dev) {
1306 err = -ENODEV;
1307 goto out;
1308 }
1309 if (dev->type != ARPHRD_CAN) {
1310 dev_put(dev);
1311 err = -ENODEV;
1312 goto out;
1313 }
1314 if (dev->mtu < so->ll.mtu) {
1315 dev_put(dev);
1316 err = -EINVAL;
1317 goto out;
1318 }
1319 if (!(dev->flags & IFF_UP))
1320 notify_enetdown = 1;
1321
1322 ifindex = dev->ifindex;
1323
1324 if (isotp_register_rxid(so))
1325 can_rx_register(net, dev, rx_id, SINGLE_MASK(rx_id),
1326 isotp_rcv, sk, "isotp", sk);
1327
1328 /* no consecutive frame echo skb in flight */
1329 so->cfecho = 0;
1330
1331 /* register for echo skb's */
1332 can_rx_register(net, dev, tx_id, SINGLE_MASK(tx_id),
1333 isotp_rcv_echo, sk, "isotpe", sk);
1334
1335 dev_put(dev);
1336
1337 /* switch to new settings */
1338 so->ifindex = ifindex;
1339 so->rxid = rx_id;
1340 so->txid = tx_id;
1341 so->bound = 1;
1342
1343 out:
1344 release_sock(sk);
1345
1346 if (notify_enetdown) {
1347 sk->sk_err = ENETDOWN;
1348 if (!sock_flag(sk, SOCK_DEAD))
1349 sk_error_report(sk);
1350 }
1351
1352 return err;
1353 }
1354
1355 static int isotp_getname(struct socket *sock, struct sockaddr *uaddr, int peer)
1356 {
1357 struct sockaddr_can *addr = (struct sockaddr_can *)uaddr;
1358 struct sock *sk = sock->sk;
1359 struct isotp_sock *so = isotp_sk(sk);
1360
1361 if (peer)
1362 return -EOPNOTSUPP;
1363
1364 memset(addr, 0, ISOTP_MIN_NAMELEN);
1365 addr->can_family = AF_CAN;
1366 addr->can_ifindex = so->ifindex;
1367 addr->can_addr.tp.rx_id = so->rxid;
1368 addr->can_addr.tp.tx_id = so->txid;
1369
1370 return ISOTP_MIN_NAMELEN;
1371 }
1372
1373 static int isotp_setsockopt_locked(struct socket *sock, int level, int optname,
1374 sockptr_t optval, unsigned int optlen)
1375 {
1376 struct sock *sk = sock->sk;
1377 struct isotp_sock *so = isotp_sk(sk);
1378 int ret = 0;
1379
1380 if (so->bound)
1381 return -EISCONN;
1382
1383 switch (optname) {
1384 case CAN_ISOTP_OPTS:
1385 if (optlen != sizeof(struct can_isotp_options))
1386 return -EINVAL;
1387
1388 if (copy_from_sockptr(&so->opt, optval, optlen))
1389 return -EFAULT;
1390
1391 /* no separate rx_ext_address is given => use ext_address */
1392 if (!(so->opt.flags & CAN_ISOTP_RX_EXT_ADDR))
1393 so->opt.rx_ext_address = so->opt.ext_address;
1394
1395 /* these broadcast flags are not allowed together */
1396 if (isotp_bc_flags(so) == ISOTP_ALL_BC_FLAGS) {
1397 /* CAN_ISOTP_SF_BROADCAST is prioritized */
1398 so->opt.flags &= ~CAN_ISOTP_CF_BROADCAST;
1399
1400 /* give user feedback on wrong config attempt */
1401 ret = -EINVAL;
1402 }
1403
1404 /* check for frame_txtime changes (0 => no changes) */
1405 if (so->opt.frame_txtime) {
1406 if (so->opt.frame_txtime == CAN_ISOTP_FRAME_TXTIME_ZERO)
1407 so->frame_txtime = 0;
1408 else
1409 so->frame_txtime = so->opt.frame_txtime;
1410 }
1411 break;
1412
1413 case CAN_ISOTP_RECV_FC:
1414 if (optlen != sizeof(struct can_isotp_fc_options))
1415 return -EINVAL;
1416
1417 if (copy_from_sockptr(&so->rxfc, optval, optlen))
1418 return -EFAULT;
1419 break;
1420
1421 case CAN_ISOTP_TX_STMIN:
1422 if (optlen != sizeof(u32))
1423 return -EINVAL;
1424
1425 if (copy_from_sockptr(&so->force_tx_stmin, optval, optlen))
1426 return -EFAULT;
1427 break;
1428
1429 case CAN_ISOTP_RX_STMIN:
1430 if (optlen != sizeof(u32))
1431 return -EINVAL;
1432
1433 if (copy_from_sockptr(&so->force_rx_stmin, optval, optlen))
1434 return -EFAULT;
1435 break;
1436
1437 case CAN_ISOTP_LL_OPTS:
1438 if (optlen == sizeof(struct can_isotp_ll_options)) {
1439 struct can_isotp_ll_options ll;
1440
1441 if (copy_from_sockptr(&ll, optval, optlen))
1442 return -EFAULT;
1443
1444 /* check for correct ISO 11898-1 DLC data length */
1445 if (ll.tx_dl != padlen(ll.tx_dl))
1446 return -EINVAL;
1447
1448 if (ll.mtu != CAN_MTU && ll.mtu != CANFD_MTU)
1449 return -EINVAL;
1450
1451 if (ll.mtu == CAN_MTU &&
1452 (ll.tx_dl > CAN_MAX_DLEN || ll.tx_flags != 0))
1453 return -EINVAL;
1454
1455 memcpy(&so->ll, &ll, sizeof(ll));
1456
1457 /* set ll_dl for tx path to similar place as for rx */
1458 so->tx.ll_dl = ll.tx_dl;
1459 } else {
1460 return -EINVAL;
1461 }
1462 break;
1463
1464 default:
1465 ret = -ENOPROTOOPT;
1466 }
1467
1468 return ret;
1469 }
1470
1471 static int isotp_setsockopt(struct socket *sock, int level, int optname,
1472 sockptr_t optval, unsigned int optlen)
1473
1474 {
1475 struct sock *sk = sock->sk;
1476 int ret;
1477
1478 if (level != SOL_CAN_ISOTP)
1479 return -EINVAL;
1480
1481 lock_sock(sk);
1482 ret = isotp_setsockopt_locked(sock, level, optname, optval, optlen);
1483 release_sock(sk);
1484 return ret;
1485 }
1486
1487 static int isotp_getsockopt(struct socket *sock, int level, int optname,
1488 char __user *optval, int __user *optlen)
1489 {
1490 struct sock *sk = sock->sk;
1491 struct isotp_sock *so = isotp_sk(sk);
1492 int len;
1493 void *val;
1494
1495 if (level != SOL_CAN_ISOTP)
1496 return -EINVAL;
1497 if (get_user(len, optlen))
1498 return -EFAULT;
1499 if (len < 0)
1500 return -EINVAL;
1501
1502 switch (optname) {
1503 case CAN_ISOTP_OPTS:
1504 len = min_t(int, len, sizeof(struct can_isotp_options));
1505 val = &so->opt;
1506 break;
1507
1508 case CAN_ISOTP_RECV_FC:
1509 len = min_t(int, len, sizeof(struct can_isotp_fc_options));
1510 val = &so->rxfc;
1511 break;
1512
1513 case CAN_ISOTP_TX_STMIN:
1514 len = min_t(int, len, sizeof(u32));
1515 val = &so->force_tx_stmin;
1516 break;
1517
1518 case CAN_ISOTP_RX_STMIN:
1519 len = min_t(int, len, sizeof(u32));
1520 val = &so->force_rx_stmin;
1521 break;
1522
1523 case CAN_ISOTP_LL_OPTS:
1524 len = min_t(int, len, sizeof(struct can_isotp_ll_options));
1525 val = &so->ll;
1526 break;
1527
1528 default:
1529 return -ENOPROTOOPT;
1530 }
1531
1532 if (put_user(len, optlen))
1533 return -EFAULT;
1534 if (copy_to_user(optval, val, len))
1535 return -EFAULT;
1536 return 0;
1537 }
1538
1539 static void isotp_notify(struct isotp_sock *so, unsigned long msg,
1540 struct net_device *dev)
1541 {
1542 struct sock *sk = &so->sk;
1543
1544 if (!net_eq(dev_net(dev), sock_net(sk)))
1545 return;
1546
1547 if (so->ifindex != dev->ifindex)
1548 return;
1549
1550 switch (msg) {
1551 case NETDEV_UNREGISTER:
1552 lock_sock(sk);
1553 /* remove current filters & unregister */
1554 if (so->bound) {
1555 if (isotp_register_rxid(so))
1556 can_rx_unregister(dev_net(dev), dev, so->rxid,
1557 SINGLE_MASK(so->rxid),
1558 isotp_rcv, sk);
1559
1560 can_rx_unregister(dev_net(dev), dev, so->txid,
1561 SINGLE_MASK(so->txid),
1562 isotp_rcv_echo, sk);
1563 }
1564
1565 so->ifindex = 0;
1566 so->bound = 0;
1567 release_sock(sk);
1568
1569 sk->sk_err = ENODEV;
1570 if (!sock_flag(sk, SOCK_DEAD))
1571 sk_error_report(sk);
1572 break;
1573
1574 case NETDEV_DOWN:
1575 sk->sk_err = ENETDOWN;
1576 if (!sock_flag(sk, SOCK_DEAD))
1577 sk_error_report(sk);
1578 break;
1579 }
1580 }
1581
1582 static int isotp_notifier(struct notifier_block *nb, unsigned long msg,
1583 void *ptr)
1584 {
1585 struct net_device *dev = netdev_notifier_info_to_dev(ptr);
1586
1587 if (dev->type != ARPHRD_CAN)
1588 return NOTIFY_DONE;
1589 if (msg != NETDEV_UNREGISTER && msg != NETDEV_DOWN)
1590 return NOTIFY_DONE;
1591 if (unlikely(isotp_busy_notifier)) /* Check for reentrant bug. */
1592 return NOTIFY_DONE;
1593
1594 spin_lock(&isotp_notifier_lock);
1595 list_for_each_entry(isotp_busy_notifier, &isotp_notifier_list, notifier) {
1596 spin_unlock(&isotp_notifier_lock);
1597 isotp_notify(isotp_busy_notifier, msg, dev);
1598 spin_lock(&isotp_notifier_lock);
1599 }
1600 isotp_busy_notifier = NULL;
1601 spin_unlock(&isotp_notifier_lock);
1602 return NOTIFY_DONE;
1603 }
1604
1605 static int isotp_init(struct sock *sk)
1606 {
1607 struct isotp_sock *so = isotp_sk(sk);
1608
1609 so->ifindex = 0;
1610 so->bound = 0;
1611
1612 so->opt.flags = CAN_ISOTP_DEFAULT_FLAGS;
1613 so->opt.ext_address = CAN_ISOTP_DEFAULT_EXT_ADDRESS;
1614 so->opt.rx_ext_address = CAN_ISOTP_DEFAULT_EXT_ADDRESS;
1615 so->opt.rxpad_content = CAN_ISOTP_DEFAULT_PAD_CONTENT;
1616 so->opt.txpad_content = CAN_ISOTP_DEFAULT_PAD_CONTENT;
1617 so->opt.frame_txtime = CAN_ISOTP_DEFAULT_FRAME_TXTIME;
1618 so->frame_txtime = CAN_ISOTP_DEFAULT_FRAME_TXTIME;
1619 so->rxfc.bs = CAN_ISOTP_DEFAULT_RECV_BS;
1620 so->rxfc.stmin = CAN_ISOTP_DEFAULT_RECV_STMIN;
1621 so->rxfc.wftmax = CAN_ISOTP_DEFAULT_RECV_WFTMAX;
1622 so->ll.mtu = CAN_ISOTP_DEFAULT_LL_MTU;
1623 so->ll.tx_dl = CAN_ISOTP_DEFAULT_LL_TX_DL;
1624 so->ll.tx_flags = CAN_ISOTP_DEFAULT_LL_TX_FLAGS;
1625
1626 /* set ll_dl for tx path to similar place as for rx */
1627 so->tx.ll_dl = so->ll.tx_dl;
1628
1629 so->rx.state = ISOTP_IDLE;
1630 so->tx.state = ISOTP_IDLE;
1631
1632 so->rx.buf = so->rx.sbuf;
1633 so->tx.buf = so->tx.sbuf;
1634 so->rx.buflen = ARRAY_SIZE(so->rx.sbuf);
1635 so->tx.buflen = ARRAY_SIZE(so->tx.sbuf);
1636
1637 hrtimer_init(&so->rxtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_SOFT);
1638 so->rxtimer.function = isotp_rx_timer_handler;
1639 hrtimer_init(&so->txtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_SOFT);
1640 so->txtimer.function = isotp_tx_timer_handler;
1641 hrtimer_init(&so->txfrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_SOFT);
1642 so->txfrtimer.function = isotp_txfr_timer_handler;
1643
1644 init_waitqueue_head(&so->wait);
1645 spin_lock_init(&so->rx_lock);
1646
1647 spin_lock(&isotp_notifier_lock);
1648 list_add_tail(&so->notifier, &isotp_notifier_list);
1649 spin_unlock(&isotp_notifier_lock);
1650
1651 return 0;
1652 }
1653
1654 static __poll_t isotp_poll(struct file *file, struct socket *sock, poll_table *wait)
1655 {
1656 struct sock *sk = sock->sk;
1657 struct isotp_sock *so = isotp_sk(sk);
1658
1659 __poll_t mask = datagram_poll(file, sock, wait);
1660 poll_wait(file, &so->wait, wait);
1661
1662 /* Check for false positives due to TX state */
1663 if ((mask & EPOLLWRNORM) && (so->tx.state != ISOTP_IDLE))
1664 mask &= ~(EPOLLOUT | EPOLLWRNORM);
1665
1666 return mask;
1667 }
1668
1669 static int isotp_sock_no_ioctlcmd(struct socket *sock, unsigned int cmd,
1670 unsigned long arg)
1671 {
1672 /* no ioctls for socket layer -> hand it down to NIC layer */
1673 return -ENOIOCTLCMD;
1674 }
1675
1676 static const struct proto_ops isotp_ops = {
1677 .family = PF_CAN,
1678 .release = isotp_release,
1679 .bind = isotp_bind,
1680 .connect = sock_no_connect,
1681 .socketpair = sock_no_socketpair,
1682 .accept = sock_no_accept,
1683 .getname = isotp_getname,
1684 .poll = isotp_poll,
1685 .ioctl = isotp_sock_no_ioctlcmd,
1686 .gettstamp = sock_gettstamp,
1687 .listen = sock_no_listen,
1688 .shutdown = sock_no_shutdown,
1689 .setsockopt = isotp_setsockopt,
1690 .getsockopt = isotp_getsockopt,
1691 .sendmsg = isotp_sendmsg,
1692 .recvmsg = isotp_recvmsg,
1693 .mmap = sock_no_mmap,
1694 };
1695
1696 static struct proto isotp_proto __read_mostly = {
1697 .name = "CAN_ISOTP",
1698 .owner = THIS_MODULE,
1699 .obj_size = sizeof(struct isotp_sock),
1700 .init = isotp_init,
1701 };
1702
1703 static const struct can_proto isotp_can_proto = {
1704 .type = SOCK_DGRAM,
1705 .protocol = CAN_ISOTP,
1706 .ops = &isotp_ops,
1707 .prot = &isotp_proto,
1708 };
1709
1710 static struct notifier_block canisotp_notifier = {
1711 .notifier_call = isotp_notifier
1712 };
1713
1714 static __init int isotp_module_init(void)
1715 {
1716 int err;
1717
1718 max_pdu_size = max_t(unsigned int, max_pdu_size, MAX_12BIT_PDU_SIZE);
1719 max_pdu_size = min_t(unsigned int, max_pdu_size, MAX_PDU_SIZE);
1720
1721 pr_info("can: isotp protocol (max_pdu_size %d)\n", max_pdu_size);
1722
1723 err = can_proto_register(&isotp_can_proto);
1724 if (err < 0)
1725 pr_err("can: registration of isotp protocol failed %pe\n", ERR_PTR(err));
1726 else
1727 register_netdevice_notifier(&canisotp_notifier);
1728
1729 return err;
1730 }
1731
1732 static __exit void isotp_module_exit(void)
1733 {
1734 can_proto_unregister(&isotp_can_proto);
1735 unregister_netdevice_notifier(&canisotp_notifier);
1736 }
1737
1738 module_init(isotp_module_init);
1739 module_exit(isotp_module_exit);
1740
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