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 isotp 15765-2:2016 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 /* ISO 15765-2:2016 supports more than 4095 byte per ISO PDU as the FF_DL can
87 * take full 32 bit values (4 Gbyte). We would need some good concept to handle
88 * this between user space and kernel space. For now increase the static buffer
89 * to something about 64 kbyte to be able to test this new functionality.
90 */
91 #define MAX_MSG_LENGTH 66000
92
93 /* N_PCI type values in bits 7-4 of N_PCI bytes */
94 #define N_PCI_SF 0x00 /* single frame */
95 #define N_PCI_FF 0x10 /* first frame */
96 #define N_PCI_CF 0x20 /* consecutive frame */
97 #define N_PCI_FC 0x30 /* flow control */
98
99 #define N_PCI_SZ 1 /* size of the PCI byte #1 */
100 #define SF_PCI_SZ4 1 /* size of SingleFrame PCI including 4 bit SF_DL */
101 #define SF_PCI_SZ8 2 /* size of SingleFrame PCI including 8 bit SF_DL */
102 #define FF_PCI_SZ12 2 /* size of FirstFrame PCI including 12 bit FF_DL */
103 #define FF_PCI_SZ32 6 /* size of FirstFrame PCI including 32 bit FF_DL */
104 #define FC_CONTENT_SZ 3 /* flow control content size in byte (FS/BS/STmin) */
105
106 #define ISOTP_CHECK_PADDING (CAN_ISOTP_CHK_PAD_LEN | CAN_ISOTP_CHK_PAD_DATA)
107 #define ISOTP_ALL_BC_FLAGS (CAN_ISOTP_SF_BROADCAST | CAN_ISOTP_CF_BROADCAST)
108
109 /* Flow Status given in FC frame */
110 #define ISOTP_FC_CTS 0 /* clear to send */
111 #define ISOTP_FC_WT 1 /* wait */
112 #define ISOTP_FC_OVFLW 2 /* overflow */
113
114 #define ISOTP_FC_TIMEOUT 1 /* 1 sec */
115 #define ISOTP_ECHO_TIMEOUT 2 /* 2 secs */
116
117 enum {
118 ISOTP_IDLE = 0,
119 ISOTP_WAIT_FIRST_FC,
120 ISOTP_WAIT_FC,
121 ISOTP_WAIT_DATA,
122 ISOTP_SENDING,
123 ISOTP_SHUTDOWN,
124 };
125
126 struct tpcon {
127 unsigned int idx;
128 unsigned int len;
129 u32 state;
130 u8 bs;
131 u8 sn;
132 u8 ll_dl;
133 u8 buf[MAX_MSG_LENGTH + 1];
134 };
135
136 struct isotp_sock {
137 struct sock sk;
138 int bound;
139 int ifindex;
140 canid_t txid;
141 canid_t rxid;
142 ktime_t tx_gap;
143 ktime_t lastrxcf_tstamp;
144 struct hrtimer rxtimer, txtimer, txfrtimer;
145 struct can_isotp_options opt;
146 struct can_isotp_fc_options rxfc, txfc;
147 struct can_isotp_ll_options ll;
148 u32 frame_txtime;
149 u32 force_tx_stmin;
150 u32 force_rx_stmin;
151 u32 cfecho; /* consecutive frame echo tag */
152 struct tpcon rx, tx;
153 struct list_head notifier;
154 wait_queue_head_t wait;
155 spinlock_t rx_lock; /* protect single thread state machine */
156 };
157
158 static LIST_HEAD(isotp_notifier_list);
159 static DEFINE_SPINLOCK(isotp_notifier_lock);
160 static struct isotp_sock *isotp_busy_notifier;
161
isotp_sk(const struct sock * sk)162 static inline struct isotp_sock *isotp_sk(const struct sock *sk)
163 {
164 return (struct isotp_sock *)sk;
165 }
166
isotp_bc_flags(struct isotp_sock * so)167 static u32 isotp_bc_flags(struct isotp_sock *so)
168 {
169 return so->opt.flags & ISOTP_ALL_BC_FLAGS;
170 }
171
isotp_register_rxid(struct isotp_sock * so)172 static bool isotp_register_rxid(struct isotp_sock *so)
173 {
174 /* no broadcast modes => register rx_id for FC frame reception */
175 return (isotp_bc_flags(so) == 0);
176 }
177
isotp_rx_timer_handler(struct hrtimer * hrtimer)178 static enum hrtimer_restart isotp_rx_timer_handler(struct hrtimer *hrtimer)
179 {
180 struct isotp_sock *so = container_of(hrtimer, struct isotp_sock,
181 rxtimer);
182 struct sock *sk = &so->sk;
183
184 if (so->rx.state == ISOTP_WAIT_DATA) {
185 /* we did not get new data frames in time */
186
187 /* report 'connection timed out' */
188 sk->sk_err = ETIMEDOUT;
189 if (!sock_flag(sk, SOCK_DEAD))
190 sk->sk_error_report(sk);
191
192 /* reset rx state */
193 so->rx.state = ISOTP_IDLE;
194 }
195
196 return HRTIMER_NORESTART;
197 }
198
isotp_send_fc(struct sock * sk,int ae,u8 flowstatus)199 static int isotp_send_fc(struct sock *sk, int ae, u8 flowstatus)
200 {
201 struct net_device *dev;
202 struct sk_buff *nskb;
203 struct canfd_frame *ncf;
204 struct isotp_sock *so = isotp_sk(sk);
205 int can_send_ret;
206
207 nskb = alloc_skb(so->ll.mtu + sizeof(struct can_skb_priv), gfp_any());
208 if (!nskb)
209 return 1;
210
211 dev = dev_get_by_index(sock_net(sk), so->ifindex);
212 if (!dev) {
213 kfree_skb(nskb);
214 return 1;
215 }
216
217 can_skb_reserve(nskb);
218 can_skb_prv(nskb)->ifindex = dev->ifindex;
219 can_skb_prv(nskb)->skbcnt = 0;
220
221 nskb->dev = dev;
222 can_skb_set_owner(nskb, sk);
223 ncf = (struct canfd_frame *)nskb->data;
224 skb_put_zero(nskb, so->ll.mtu);
225
226 /* create & send flow control reply */
227 ncf->can_id = so->txid;
228
229 if (so->opt.flags & CAN_ISOTP_TX_PADDING) {
230 memset(ncf->data, so->opt.txpad_content, CAN_MAX_DLEN);
231 ncf->len = CAN_MAX_DLEN;
232 } else {
233 ncf->len = ae + FC_CONTENT_SZ;
234 }
235
236 ncf->data[ae] = N_PCI_FC | flowstatus;
237 ncf->data[ae + 1] = so->rxfc.bs;
238 ncf->data[ae + 2] = so->rxfc.stmin;
239
240 if (ae)
241 ncf->data[0] = so->opt.ext_address;
242
243 ncf->flags = so->ll.tx_flags;
244
245 can_send_ret = can_send(nskb, 1);
246 if (can_send_ret)
247 pr_notice_once("can-isotp: %s: can_send_ret %pe\n",
248 __func__, ERR_PTR(can_send_ret));
249
250 dev_put(dev);
251
252 /* reset blocksize counter */
253 so->rx.bs = 0;
254
255 /* reset last CF frame rx timestamp for rx stmin enforcement */
256 so->lastrxcf_tstamp = ktime_set(0, 0);
257
258 /* start rx timeout watchdog */
259 hrtimer_start(&so->rxtimer, ktime_set(ISOTP_FC_TIMEOUT, 0),
260 HRTIMER_MODE_REL_SOFT);
261 return 0;
262 }
263
isotp_rcv_skb(struct sk_buff * skb,struct sock * sk)264 static void isotp_rcv_skb(struct sk_buff *skb, struct sock *sk)
265 {
266 struct sockaddr_can *addr = (struct sockaddr_can *)skb->cb;
267
268 BUILD_BUG_ON(sizeof(skb->cb) < sizeof(struct sockaddr_can));
269
270 memset(addr, 0, sizeof(*addr));
271 addr->can_family = AF_CAN;
272 addr->can_ifindex = skb->dev->ifindex;
273
274 if (sock_queue_rcv_skb(sk, skb) < 0)
275 kfree_skb(skb);
276 }
277
padlen(u8 datalen)278 static u8 padlen(u8 datalen)
279 {
280 static const u8 plen[] = {
281 8, 8, 8, 8, 8, 8, 8, 8, 8, /* 0 - 8 */
282 12, 12, 12, 12, /* 9 - 12 */
283 16, 16, 16, 16, /* 13 - 16 */
284 20, 20, 20, 20, /* 17 - 20 */
285 24, 24, 24, 24, /* 21 - 24 */
286 32, 32, 32, 32, 32, 32, 32, 32, /* 25 - 32 */
287 48, 48, 48, 48, 48, 48, 48, 48, /* 33 - 40 */
288 48, 48, 48, 48, 48, 48, 48, 48 /* 41 - 48 */
289 };
290
291 if (datalen > 48)
292 return 64;
293
294 return plen[datalen];
295 }
296
297 /* check for length optimization and return 1/true when the check fails */
check_optimized(struct canfd_frame * cf,int start_index)298 static int check_optimized(struct canfd_frame *cf, int start_index)
299 {
300 /* for CAN_DL <= 8 the start_index is equal to the CAN_DL as the
301 * padding would start at this point. E.g. if the padding would
302 * start at cf.data[7] cf->len has to be 7 to be optimal.
303 * Note: The data[] index starts with zero.
304 */
305 if (cf->len <= CAN_MAX_DLEN)
306 return (cf->len != start_index);
307
308 /* This relation is also valid in the non-linear DLC range, where
309 * we need to take care of the minimal next possible CAN_DL.
310 * The correct check would be (padlen(cf->len) != padlen(start_index)).
311 * But as cf->len can only take discrete values from 12, .., 64 at this
312 * point the padlen(cf->len) is always equal to cf->len.
313 */
314 return (cf->len != padlen(start_index));
315 }
316
317 /* check padding and return 1/true when the check fails */
check_pad(struct isotp_sock * so,struct canfd_frame * cf,int start_index,u8 content)318 static int check_pad(struct isotp_sock *so, struct canfd_frame *cf,
319 int start_index, u8 content)
320 {
321 int i;
322
323 /* no RX_PADDING value => check length of optimized frame length */
324 if (!(so->opt.flags & CAN_ISOTP_RX_PADDING)) {
325 if (so->opt.flags & CAN_ISOTP_CHK_PAD_LEN)
326 return check_optimized(cf, start_index);
327
328 /* no valid test against empty value => ignore frame */
329 return 1;
330 }
331
332 /* check datalength of correctly padded CAN frame */
333 if ((so->opt.flags & CAN_ISOTP_CHK_PAD_LEN) &&
334 cf->len != padlen(cf->len))
335 return 1;
336
337 /* check padding content */
338 if (so->opt.flags & CAN_ISOTP_CHK_PAD_DATA) {
339 for (i = start_index; i < cf->len; i++)
340 if (cf->data[i] != content)
341 return 1;
342 }
343 return 0;
344 }
345
346 static void isotp_send_cframe(struct isotp_sock *so);
347
isotp_rcv_fc(struct isotp_sock * so,struct canfd_frame * cf,int ae)348 static int isotp_rcv_fc(struct isotp_sock *so, struct canfd_frame *cf, int ae)
349 {
350 struct sock *sk = &so->sk;
351
352 if (so->tx.state != ISOTP_WAIT_FC &&
353 so->tx.state != ISOTP_WAIT_FIRST_FC)
354 return 0;
355
356 hrtimer_cancel(&so->txtimer);
357
358 if ((cf->len < ae + FC_CONTENT_SZ) ||
359 ((so->opt.flags & ISOTP_CHECK_PADDING) &&
360 check_pad(so, cf, ae + FC_CONTENT_SZ, so->opt.rxpad_content))) {
361 /* malformed PDU - report 'not a data message' */
362 sk->sk_err = EBADMSG;
363 if (!sock_flag(sk, SOCK_DEAD))
364 sk->sk_error_report(sk);
365
366 so->tx.state = ISOTP_IDLE;
367 wake_up_interruptible(&so->wait);
368 return 1;
369 }
370
371 /* get communication parameters only from the first FC frame */
372 if (so->tx.state == ISOTP_WAIT_FIRST_FC) {
373 so->txfc.bs = cf->data[ae + 1];
374 so->txfc.stmin = cf->data[ae + 2];
375
376 /* fix wrong STmin values according spec */
377 if (so->txfc.stmin > 0x7F &&
378 (so->txfc.stmin < 0xF1 || so->txfc.stmin > 0xF9))
379 so->txfc.stmin = 0x7F;
380
381 so->tx_gap = ktime_set(0, 0);
382 /* add transmission time for CAN frame N_As */
383 so->tx_gap = ktime_add_ns(so->tx_gap, so->frame_txtime);
384 /* add waiting time for consecutive frames N_Cs */
385 if (so->opt.flags & CAN_ISOTP_FORCE_TXSTMIN)
386 so->tx_gap = ktime_add_ns(so->tx_gap,
387 so->force_tx_stmin);
388 else if (so->txfc.stmin < 0x80)
389 so->tx_gap = ktime_add_ns(so->tx_gap,
390 so->txfc.stmin * 1000000);
391 else
392 so->tx_gap = ktime_add_ns(so->tx_gap,
393 (so->txfc.stmin - 0xF0)
394 * 100000);
395 so->tx.state = ISOTP_WAIT_FC;
396 }
397
398 switch (cf->data[ae] & 0x0F) {
399 case ISOTP_FC_CTS:
400 so->tx.bs = 0;
401 so->tx.state = ISOTP_SENDING;
402 /* send CF frame and enable echo timeout handling */
403 hrtimer_start(&so->txtimer, ktime_set(ISOTP_ECHO_TIMEOUT, 0),
404 HRTIMER_MODE_REL_SOFT);
405 isotp_send_cframe(so);
406 break;
407
408 case ISOTP_FC_WT:
409 /* start timer to wait for next FC frame */
410 hrtimer_start(&so->txtimer, ktime_set(ISOTP_FC_TIMEOUT, 0),
411 HRTIMER_MODE_REL_SOFT);
412 break;
413
414 case ISOTP_FC_OVFLW:
415 /* overflow on receiver side - report 'message too long' */
416 sk->sk_err = EMSGSIZE;
417 if (!sock_flag(sk, SOCK_DEAD))
418 sk->sk_error_report(sk);
419 fallthrough;
420
421 default:
422 /* stop this tx job */
423 so->tx.state = ISOTP_IDLE;
424 wake_up_interruptible(&so->wait);
425 }
426 return 0;
427 }
428
isotp_rcv_sf(struct sock * sk,struct canfd_frame * cf,int pcilen,struct sk_buff * skb,int len)429 static int isotp_rcv_sf(struct sock *sk, struct canfd_frame *cf, int pcilen,
430 struct sk_buff *skb, int len)
431 {
432 struct isotp_sock *so = isotp_sk(sk);
433 struct sk_buff *nskb;
434
435 hrtimer_cancel(&so->rxtimer);
436 so->rx.state = ISOTP_IDLE;
437
438 if (!len || len > cf->len - pcilen)
439 return 1;
440
441 if ((so->opt.flags & ISOTP_CHECK_PADDING) &&
442 check_pad(so, cf, pcilen + len, so->opt.rxpad_content)) {
443 /* malformed PDU - report 'not a data message' */
444 sk->sk_err = EBADMSG;
445 if (!sock_flag(sk, SOCK_DEAD))
446 sk->sk_error_report(sk);
447 return 1;
448 }
449
450 nskb = alloc_skb(len, gfp_any());
451 if (!nskb)
452 return 1;
453
454 memcpy(skb_put(nskb, len), &cf->data[pcilen], len);
455
456 nskb->tstamp = skb->tstamp;
457 nskb->dev = skb->dev;
458 isotp_rcv_skb(nskb, sk);
459 return 0;
460 }
461
isotp_rcv_ff(struct sock * sk,struct canfd_frame * cf,int ae)462 static int isotp_rcv_ff(struct sock *sk, struct canfd_frame *cf, int ae)
463 {
464 struct isotp_sock *so = isotp_sk(sk);
465 int i;
466 int off;
467 int ff_pci_sz;
468
469 hrtimer_cancel(&so->rxtimer);
470 so->rx.state = ISOTP_IDLE;
471
472 /* get the used sender LL_DL from the (first) CAN frame data length */
473 so->rx.ll_dl = padlen(cf->len);
474
475 /* the first frame has to use the entire frame up to LL_DL length */
476 if (cf->len != so->rx.ll_dl)
477 return 1;
478
479 /* get the FF_DL */
480 so->rx.len = (cf->data[ae] & 0x0F) << 8;
481 so->rx.len += cf->data[ae + 1];
482
483 /* Check for FF_DL escape sequence supporting 32 bit PDU length */
484 if (so->rx.len) {
485 ff_pci_sz = FF_PCI_SZ12;
486 } else {
487 /* FF_DL = 0 => get real length from next 4 bytes */
488 so->rx.len = cf->data[ae + 2] << 24;
489 so->rx.len += cf->data[ae + 3] << 16;
490 so->rx.len += cf->data[ae + 4] << 8;
491 so->rx.len += cf->data[ae + 5];
492 ff_pci_sz = FF_PCI_SZ32;
493 }
494
495 /* take care of a potential SF_DL ESC offset for TX_DL > 8 */
496 off = (so->rx.ll_dl > CAN_MAX_DLEN) ? 1 : 0;
497
498 if (so->rx.len + ae + off + ff_pci_sz < so->rx.ll_dl)
499 return 1;
500
501 if (so->rx.len > MAX_MSG_LENGTH) {
502 /* send FC frame with overflow status */
503 isotp_send_fc(sk, ae, ISOTP_FC_OVFLW);
504 return 1;
505 }
506
507 /* copy the first received data bytes */
508 so->rx.idx = 0;
509 for (i = ae + ff_pci_sz; i < so->rx.ll_dl; i++)
510 so->rx.buf[so->rx.idx++] = cf->data[i];
511
512 /* initial setup for this pdu reception */
513 so->rx.sn = 1;
514 so->rx.state = ISOTP_WAIT_DATA;
515
516 /* no creation of flow control frames */
517 if (so->opt.flags & CAN_ISOTP_LISTEN_MODE)
518 return 0;
519
520 /* send our first FC frame */
521 isotp_send_fc(sk, ae, ISOTP_FC_CTS);
522 return 0;
523 }
524
isotp_rcv_cf(struct sock * sk,struct canfd_frame * cf,int ae,struct sk_buff * skb)525 static int isotp_rcv_cf(struct sock *sk, struct canfd_frame *cf, int ae,
526 struct sk_buff *skb)
527 {
528 struct isotp_sock *so = isotp_sk(sk);
529 struct sk_buff *nskb;
530 int i;
531
532 if (so->rx.state != ISOTP_WAIT_DATA)
533 return 0;
534
535 /* drop if timestamp gap is less than force_rx_stmin nano secs */
536 if (so->opt.flags & CAN_ISOTP_FORCE_RXSTMIN) {
537 if (ktime_to_ns(ktime_sub(skb->tstamp, so->lastrxcf_tstamp)) <
538 so->force_rx_stmin)
539 return 0;
540
541 so->lastrxcf_tstamp = skb->tstamp;
542 }
543
544 hrtimer_cancel(&so->rxtimer);
545
546 /* CFs are never longer than the FF */
547 if (cf->len > so->rx.ll_dl)
548 return 1;
549
550 /* CFs have usually the LL_DL length */
551 if (cf->len < so->rx.ll_dl) {
552 /* this is only allowed for the last CF */
553 if (so->rx.len - so->rx.idx > so->rx.ll_dl - ae - N_PCI_SZ)
554 return 1;
555 }
556
557 if ((cf->data[ae] & 0x0F) != so->rx.sn) {
558 /* wrong sn detected - report 'illegal byte sequence' */
559 sk->sk_err = EILSEQ;
560 if (!sock_flag(sk, SOCK_DEAD))
561 sk->sk_error_report(sk);
562
563 /* reset rx state */
564 so->rx.state = ISOTP_IDLE;
565 return 1;
566 }
567 so->rx.sn++;
568 so->rx.sn %= 16;
569
570 for (i = ae + N_PCI_SZ; i < cf->len; i++) {
571 so->rx.buf[so->rx.idx++] = cf->data[i];
572 if (so->rx.idx >= so->rx.len)
573 break;
574 }
575
576 if (so->rx.idx >= so->rx.len) {
577 /* we are done */
578 so->rx.state = ISOTP_IDLE;
579
580 if ((so->opt.flags & ISOTP_CHECK_PADDING) &&
581 check_pad(so, cf, i + 1, so->opt.rxpad_content)) {
582 /* malformed PDU - report 'not a data message' */
583 sk->sk_err = EBADMSG;
584 if (!sock_flag(sk, SOCK_DEAD))
585 sk->sk_error_report(sk);
586 return 1;
587 }
588
589 nskb = alloc_skb(so->rx.len, gfp_any());
590 if (!nskb)
591 return 1;
592
593 memcpy(skb_put(nskb, so->rx.len), so->rx.buf,
594 so->rx.len);
595
596 nskb->tstamp = skb->tstamp;
597 nskb->dev = skb->dev;
598 isotp_rcv_skb(nskb, sk);
599 return 0;
600 }
601
602 /* perform blocksize handling, if enabled */
603 if (!so->rxfc.bs || ++so->rx.bs < so->rxfc.bs) {
604 /* start rx timeout watchdog */
605 hrtimer_start(&so->rxtimer, ktime_set(ISOTP_FC_TIMEOUT, 0),
606 HRTIMER_MODE_REL_SOFT);
607 return 0;
608 }
609
610 /* no creation of flow control frames */
611 if (so->opt.flags & CAN_ISOTP_LISTEN_MODE)
612 return 0;
613
614 /* we reached the specified blocksize so->rxfc.bs */
615 isotp_send_fc(sk, ae, ISOTP_FC_CTS);
616 return 0;
617 }
618
isotp_rcv(struct sk_buff * skb,void * data)619 static void isotp_rcv(struct sk_buff *skb, void *data)
620 {
621 struct sock *sk = (struct sock *)data;
622 struct isotp_sock *so = isotp_sk(sk);
623 struct canfd_frame *cf;
624 int ae = (so->opt.flags & CAN_ISOTP_EXTEND_ADDR) ? 1 : 0;
625 u8 n_pci_type, sf_dl;
626
627 /* Strictly receive only frames with the configured MTU size
628 * => clear separation of CAN2.0 / CAN FD transport channels
629 */
630 if (skb->len != so->ll.mtu)
631 return;
632
633 cf = (struct canfd_frame *)skb->data;
634
635 /* if enabled: check reception of my configured extended address */
636 if (ae && cf->data[0] != so->opt.rx_ext_address)
637 return;
638
639 n_pci_type = cf->data[ae] & 0xF0;
640
641 /* Make sure the state changes and data structures stay consistent at
642 * CAN frame reception time. This locking is not needed in real world
643 * use cases but the inconsistency can be triggered with syzkaller.
644 */
645 spin_lock(&so->rx_lock);
646
647 if (so->opt.flags & CAN_ISOTP_HALF_DUPLEX) {
648 /* check rx/tx path half duplex expectations */
649 if ((so->tx.state != ISOTP_IDLE && n_pci_type != N_PCI_FC) ||
650 (so->rx.state != ISOTP_IDLE && n_pci_type == N_PCI_FC))
651 goto out_unlock;
652 }
653
654 switch (n_pci_type) {
655 case N_PCI_FC:
656 /* tx path: flow control frame containing the FC parameters */
657 isotp_rcv_fc(so, cf, ae);
658 break;
659
660 case N_PCI_SF:
661 /* rx path: single frame
662 *
663 * As we do not have a rx.ll_dl configuration, we can only test
664 * if the CAN frames payload length matches the LL_DL == 8
665 * requirements - no matter if it's CAN 2.0 or CAN FD
666 */
667
668 /* get the SF_DL from the N_PCI byte */
669 sf_dl = cf->data[ae] & 0x0F;
670
671 if (cf->len <= CAN_MAX_DLEN) {
672 isotp_rcv_sf(sk, cf, SF_PCI_SZ4 + ae, skb, sf_dl);
673 } else {
674 if (skb->len == CANFD_MTU) {
675 /* We have a CAN FD frame and CAN_DL is greater than 8:
676 * Only frames with the SF_DL == 0 ESC value are valid.
677 *
678 * If so take care of the increased SF PCI size
679 * (SF_PCI_SZ8) to point to the message content behind
680 * the extended SF PCI info and get the real SF_DL
681 * length value from the formerly first data byte.
682 */
683 if (sf_dl == 0)
684 isotp_rcv_sf(sk, cf, SF_PCI_SZ8 + ae, skb,
685 cf->data[SF_PCI_SZ4 + ae]);
686 }
687 }
688 break;
689
690 case N_PCI_FF:
691 /* rx path: first frame */
692 isotp_rcv_ff(sk, cf, ae);
693 break;
694
695 case N_PCI_CF:
696 /* rx path: consecutive frame */
697 isotp_rcv_cf(sk, cf, ae, skb);
698 break;
699 }
700
701 out_unlock:
702 spin_unlock(&so->rx_lock);
703 }
704
isotp_fill_dataframe(struct canfd_frame * cf,struct isotp_sock * so,int ae,int off)705 static void isotp_fill_dataframe(struct canfd_frame *cf, struct isotp_sock *so,
706 int ae, int off)
707 {
708 int pcilen = N_PCI_SZ + ae + off;
709 int space = so->tx.ll_dl - pcilen;
710 int num = min_t(int, so->tx.len - so->tx.idx, space);
711 int i;
712
713 cf->can_id = so->txid;
714 cf->len = num + pcilen;
715
716 if (num < space) {
717 if (so->opt.flags & CAN_ISOTP_TX_PADDING) {
718 /* user requested padding */
719 cf->len = padlen(cf->len);
720 memset(cf->data, so->opt.txpad_content, cf->len);
721 } else if (cf->len > CAN_MAX_DLEN) {
722 /* mandatory padding for CAN FD frames */
723 cf->len = padlen(cf->len);
724 memset(cf->data, CAN_ISOTP_DEFAULT_PAD_CONTENT,
725 cf->len);
726 }
727 }
728
729 for (i = 0; i < num; i++)
730 cf->data[pcilen + i] = so->tx.buf[so->tx.idx++];
731
732 if (ae)
733 cf->data[0] = so->opt.ext_address;
734 }
735
isotp_send_cframe(struct isotp_sock * so)736 static void isotp_send_cframe(struct isotp_sock *so)
737 {
738 struct sock *sk = &so->sk;
739 struct sk_buff *skb;
740 struct net_device *dev;
741 struct canfd_frame *cf;
742 int can_send_ret;
743 int ae = (so->opt.flags & CAN_ISOTP_EXTEND_ADDR) ? 1 : 0;
744
745 dev = dev_get_by_index(sock_net(sk), so->ifindex);
746 if (!dev)
747 return;
748
749 skb = alloc_skb(so->ll.mtu + sizeof(struct can_skb_priv), GFP_ATOMIC);
750 if (!skb) {
751 dev_put(dev);
752 return;
753 }
754
755 can_skb_reserve(skb);
756 can_skb_prv(skb)->ifindex = dev->ifindex;
757 can_skb_prv(skb)->skbcnt = 0;
758
759 cf = (struct canfd_frame *)skb->data;
760 skb_put_zero(skb, so->ll.mtu);
761
762 /* create consecutive frame */
763 isotp_fill_dataframe(cf, so, ae, 0);
764
765 /* place consecutive frame N_PCI in appropriate index */
766 cf->data[ae] = N_PCI_CF | so->tx.sn++;
767 so->tx.sn %= 16;
768 so->tx.bs++;
769
770 cf->flags = so->ll.tx_flags;
771
772 skb->dev = dev;
773 can_skb_set_owner(skb, sk);
774
775 /* cfecho should have been zero'ed by init/isotp_rcv_echo() */
776 if (so->cfecho)
777 pr_notice_once("can-isotp: cfecho is %08X != 0\n", so->cfecho);
778
779 /* set consecutive frame echo tag */
780 so->cfecho = *(u32 *)cf->data;
781
782 /* send frame with local echo enabled */
783 can_send_ret = can_send(skb, 1);
784 if (can_send_ret) {
785 pr_notice_once("can-isotp: %s: can_send_ret %pe\n",
786 __func__, ERR_PTR(can_send_ret));
787 if (can_send_ret == -ENOBUFS)
788 pr_notice_once("can-isotp: tx queue is full\n");
789 }
790 dev_put(dev);
791 }
792
isotp_create_fframe(struct canfd_frame * cf,struct isotp_sock * so,int ae)793 static void isotp_create_fframe(struct canfd_frame *cf, struct isotp_sock *so,
794 int ae)
795 {
796 int i;
797 int ff_pci_sz;
798
799 cf->can_id = so->txid;
800 cf->len = so->tx.ll_dl;
801 if (ae)
802 cf->data[0] = so->opt.ext_address;
803
804 /* create N_PCI bytes with 12/32 bit FF_DL data length */
805 if (so->tx.len > 4095) {
806 /* use 32 bit FF_DL notation */
807 cf->data[ae] = N_PCI_FF;
808 cf->data[ae + 1] = 0;
809 cf->data[ae + 2] = (u8)(so->tx.len >> 24) & 0xFFU;
810 cf->data[ae + 3] = (u8)(so->tx.len >> 16) & 0xFFU;
811 cf->data[ae + 4] = (u8)(so->tx.len >> 8) & 0xFFU;
812 cf->data[ae + 5] = (u8)so->tx.len & 0xFFU;
813 ff_pci_sz = FF_PCI_SZ32;
814 } else {
815 /* use 12 bit FF_DL notation */
816 cf->data[ae] = (u8)(so->tx.len >> 8) | N_PCI_FF;
817 cf->data[ae + 1] = (u8)so->tx.len & 0xFFU;
818 ff_pci_sz = FF_PCI_SZ12;
819 }
820
821 /* add first data bytes depending on ae */
822 for (i = ae + ff_pci_sz; i < so->tx.ll_dl; i++)
823 cf->data[i] = so->tx.buf[so->tx.idx++];
824
825 so->tx.sn = 1;
826 }
827
isotp_rcv_echo(struct sk_buff * skb,void * data)828 static void isotp_rcv_echo(struct sk_buff *skb, void *data)
829 {
830 struct sock *sk = (struct sock *)data;
831 struct isotp_sock *so = isotp_sk(sk);
832 struct canfd_frame *cf = (struct canfd_frame *)skb->data;
833
834 /* only handle my own local echo CF/SF skb's (no FF!) */
835 if (skb->sk != sk || so->cfecho != *(u32 *)cf->data)
836 return;
837
838 /* cancel local echo timeout */
839 hrtimer_cancel(&so->txtimer);
840
841 /* local echo skb with consecutive frame has been consumed */
842 so->cfecho = 0;
843
844 if (so->tx.idx >= so->tx.len) {
845 /* we are done */
846 so->tx.state = ISOTP_IDLE;
847 wake_up_interruptible(&so->wait);
848 return;
849 }
850
851 if (so->txfc.bs && so->tx.bs >= so->txfc.bs) {
852 /* stop and wait for FC with timeout */
853 so->tx.state = ISOTP_WAIT_FC;
854 hrtimer_start(&so->txtimer, ktime_set(ISOTP_FC_TIMEOUT, 0),
855 HRTIMER_MODE_REL_SOFT);
856 return;
857 }
858
859 /* no gap between data frames needed => use burst mode */
860 if (!so->tx_gap) {
861 /* enable echo timeout handling */
862 hrtimer_start(&so->txtimer, ktime_set(ISOTP_ECHO_TIMEOUT, 0),
863 HRTIMER_MODE_REL_SOFT);
864 isotp_send_cframe(so);
865 return;
866 }
867
868 /* start timer to send next consecutive frame with correct delay */
869 hrtimer_start(&so->txfrtimer, so->tx_gap, HRTIMER_MODE_REL_SOFT);
870 }
871
isotp_tx_timer_handler(struct hrtimer * hrtimer)872 static enum hrtimer_restart isotp_tx_timer_handler(struct hrtimer *hrtimer)
873 {
874 struct isotp_sock *so = container_of(hrtimer, struct isotp_sock,
875 txtimer);
876 struct sock *sk = &so->sk;
877
878 /* don't handle timeouts in IDLE or SHUTDOWN state */
879 if (so->tx.state == ISOTP_IDLE || so->tx.state == ISOTP_SHUTDOWN)
880 return HRTIMER_NORESTART;
881
882 /* we did not get any flow control or echo frame in time */
883
884 /* report 'communication error on send' */
885 sk->sk_err = ECOMM;
886 if (!sock_flag(sk, SOCK_DEAD))
887 sk->sk_error_report(sk);
888
889 /* reset tx state */
890 so->tx.state = ISOTP_IDLE;
891 wake_up_interruptible(&so->wait);
892
893 return HRTIMER_NORESTART;
894 }
895
isotp_txfr_timer_handler(struct hrtimer * hrtimer)896 static enum hrtimer_restart isotp_txfr_timer_handler(struct hrtimer *hrtimer)
897 {
898 struct isotp_sock *so = container_of(hrtimer, struct isotp_sock,
899 txfrtimer);
900
901 /* start echo timeout handling and cover below protocol error */
902 hrtimer_start(&so->txtimer, ktime_set(ISOTP_ECHO_TIMEOUT, 0),
903 HRTIMER_MODE_REL_SOFT);
904
905 /* cfecho should be consumed by isotp_rcv_echo() here */
906 if (so->tx.state == ISOTP_SENDING && !so->cfecho)
907 isotp_send_cframe(so);
908
909 return HRTIMER_NORESTART;
910 }
911
isotp_sendmsg(struct socket * sock,struct msghdr * msg,size_t size)912 static int isotp_sendmsg(struct socket *sock, struct msghdr *msg, size_t size)
913 {
914 struct sock *sk = sock->sk;
915 struct isotp_sock *so = isotp_sk(sk);
916 struct sk_buff *skb;
917 struct net_device *dev;
918 struct canfd_frame *cf;
919 int ae = (so->opt.flags & CAN_ISOTP_EXTEND_ADDR) ? 1 : 0;
920 int wait_tx_done = (so->opt.flags & CAN_ISOTP_WAIT_TX_DONE) ? 1 : 0;
921 s64 hrtimer_sec = ISOTP_ECHO_TIMEOUT;
922 int off;
923 int err;
924
925 if (!so->bound || so->tx.state == ISOTP_SHUTDOWN)
926 return -EADDRNOTAVAIL;
927
928 while (cmpxchg(&so->tx.state, ISOTP_IDLE, ISOTP_SENDING) != ISOTP_IDLE) {
929 /* we do not support multiple buffers - for now */
930 if (msg->msg_flags & MSG_DONTWAIT)
931 return -EAGAIN;
932
933 if (so->tx.state == ISOTP_SHUTDOWN)
934 return -EADDRNOTAVAIL;
935
936 /* wait for complete transmission of current pdu */
937 err = wait_event_interruptible(so->wait, so->tx.state == ISOTP_IDLE);
938 if (err)
939 goto err_event_drop;
940 }
941
942 if (!size || size > MAX_MSG_LENGTH) {
943 err = -EINVAL;
944 goto err_out_drop;
945 }
946
947 /* take care of a potential SF_DL ESC offset for TX_DL > 8 */
948 off = (so->tx.ll_dl > CAN_MAX_DLEN) ? 1 : 0;
949
950 /* does the given data fit into a single frame for SF_BROADCAST? */
951 if ((isotp_bc_flags(so) == CAN_ISOTP_SF_BROADCAST) &&
952 (size > so->tx.ll_dl - SF_PCI_SZ4 - ae - off)) {
953 err = -EINVAL;
954 goto err_out_drop;
955 }
956
957 err = memcpy_from_msg(so->tx.buf, msg, size);
958 if (err < 0)
959 goto err_out_drop;
960
961 dev = dev_get_by_index(sock_net(sk), so->ifindex);
962 if (!dev) {
963 err = -ENXIO;
964 goto err_out_drop;
965 }
966
967 skb = sock_alloc_send_skb(sk, so->ll.mtu + sizeof(struct can_skb_priv),
968 msg->msg_flags & MSG_DONTWAIT, &err);
969 if (!skb) {
970 dev_put(dev);
971 goto err_out_drop;
972 }
973
974 can_skb_reserve(skb);
975 can_skb_prv(skb)->ifindex = dev->ifindex;
976 can_skb_prv(skb)->skbcnt = 0;
977
978 so->tx.len = size;
979 so->tx.idx = 0;
980
981 cf = (struct canfd_frame *)skb->data;
982 skb_put_zero(skb, so->ll.mtu);
983
984 /* cfecho should have been zero'ed by init / former isotp_rcv_echo() */
985 if (so->cfecho)
986 pr_notice_once("can-isotp: uninit cfecho %08X\n", so->cfecho);
987
988 /* check for single frame transmission depending on TX_DL */
989 if (size <= so->tx.ll_dl - SF_PCI_SZ4 - ae - off) {
990 /* The message size generally fits into a SingleFrame - good.
991 *
992 * SF_DL ESC offset optimization:
993 *
994 * When TX_DL is greater 8 but the message would still fit
995 * into a 8 byte CAN frame, we can omit the offset.
996 * This prevents a protocol caused length extension from
997 * CAN_DL = 8 to CAN_DL = 12 due to the SF_SL ESC handling.
998 */
999 if (size <= CAN_MAX_DLEN - SF_PCI_SZ4 - ae)
1000 off = 0;
1001
1002 isotp_fill_dataframe(cf, so, ae, off);
1003
1004 /* place single frame N_PCI w/o length in appropriate index */
1005 cf->data[ae] = N_PCI_SF;
1006
1007 /* place SF_DL size value depending on the SF_DL ESC offset */
1008 if (off)
1009 cf->data[SF_PCI_SZ4 + ae] = size;
1010 else
1011 cf->data[ae] |= size;
1012
1013 /* set CF echo tag for isotp_rcv_echo() (SF-mode) */
1014 so->cfecho = *(u32 *)cf->data;
1015 } else {
1016 /* send first frame */
1017
1018 isotp_create_fframe(cf, so, ae);
1019
1020 if (isotp_bc_flags(so) == CAN_ISOTP_CF_BROADCAST) {
1021 /* set timer for FC-less operation (STmin = 0) */
1022 if (so->opt.flags & CAN_ISOTP_FORCE_TXSTMIN)
1023 so->tx_gap = ktime_set(0, so->force_tx_stmin);
1024 else
1025 so->tx_gap = ktime_set(0, so->frame_txtime);
1026
1027 /* disable wait for FCs due to activated block size */
1028 so->txfc.bs = 0;
1029
1030 /* set CF echo tag for isotp_rcv_echo() (CF-mode) */
1031 so->cfecho = *(u32 *)cf->data;
1032 } else {
1033 /* standard flow control check */
1034 so->tx.state = ISOTP_WAIT_FIRST_FC;
1035
1036 /* start timeout for FC */
1037 hrtimer_sec = ISOTP_FC_TIMEOUT;
1038
1039 /* no CF echo tag for isotp_rcv_echo() (FF-mode) */
1040 so->cfecho = 0;
1041 }
1042 }
1043
1044 hrtimer_start(&so->txtimer, ktime_set(hrtimer_sec, 0),
1045 HRTIMER_MODE_REL_SOFT);
1046
1047 /* send the first or only CAN frame */
1048 cf->flags = so->ll.tx_flags;
1049
1050 skb->dev = dev;
1051 skb->sk = sk;
1052 err = can_send(skb, 1);
1053 dev_put(dev);
1054 if (err) {
1055 pr_notice_once("can-isotp: %s: can_send_ret %pe\n",
1056 __func__, ERR_PTR(err));
1057
1058 /* no transmission -> no timeout monitoring */
1059 hrtimer_cancel(&so->txtimer);
1060
1061 /* reset consecutive frame echo tag */
1062 so->cfecho = 0;
1063
1064 goto err_out_drop;
1065 }
1066
1067 if (wait_tx_done) {
1068 /* wait for complete transmission of current pdu */
1069 err = wait_event_interruptible(so->wait, so->tx.state == ISOTP_IDLE);
1070 if (err)
1071 goto err_event_drop;
1072
1073 err = sock_error(sk);
1074 if (err)
1075 return err;
1076 }
1077
1078 return size;
1079
1080 err_event_drop:
1081 /* got signal: force tx state machine to be idle */
1082 so->tx.state = ISOTP_IDLE;
1083 hrtimer_cancel(&so->txfrtimer);
1084 hrtimer_cancel(&so->txtimer);
1085 err_out_drop:
1086 /* drop this PDU and unlock a potential wait queue */
1087 so->tx.state = ISOTP_IDLE;
1088 wake_up_interruptible(&so->wait);
1089
1090 return err;
1091 }
1092
isotp_recvmsg(struct socket * sock,struct msghdr * msg,size_t size,int flags)1093 static int isotp_recvmsg(struct socket *sock, struct msghdr *msg, size_t size,
1094 int flags)
1095 {
1096 struct sock *sk = sock->sk;
1097 struct sk_buff *skb;
1098 struct isotp_sock *so = isotp_sk(sk);
1099 int noblock = flags & MSG_DONTWAIT;
1100 int ret = 0;
1101
1102 if (flags & ~(MSG_DONTWAIT | MSG_TRUNC | MSG_PEEK | MSG_CMSG_COMPAT))
1103 return -EINVAL;
1104
1105 if (!so->bound)
1106 return -EADDRNOTAVAIL;
1107
1108 flags &= ~MSG_DONTWAIT;
1109 skb = skb_recv_datagram(sk, flags, noblock, &ret);
1110 if (!skb)
1111 return ret;
1112
1113 if (size < skb->len)
1114 msg->msg_flags |= MSG_TRUNC;
1115 else
1116 size = skb->len;
1117
1118 ret = memcpy_to_msg(msg, skb->data, size);
1119 if (ret < 0)
1120 goto out_err;
1121
1122 sock_recv_timestamp(msg, sk, skb);
1123
1124 if (msg->msg_name) {
1125 __sockaddr_check_size(ISOTP_MIN_NAMELEN);
1126 msg->msg_namelen = ISOTP_MIN_NAMELEN;
1127 memcpy(msg->msg_name, skb->cb, msg->msg_namelen);
1128 }
1129
1130 /* set length of return value */
1131 ret = (flags & MSG_TRUNC) ? skb->len : size;
1132
1133 out_err:
1134 skb_free_datagram(sk, skb);
1135
1136 return ret;
1137 }
1138
isotp_release(struct socket * sock)1139 static int isotp_release(struct socket *sock)
1140 {
1141 struct sock *sk = sock->sk;
1142 struct isotp_sock *so;
1143 struct net *net;
1144
1145 if (!sk)
1146 return 0;
1147
1148 so = isotp_sk(sk);
1149 net = sock_net(sk);
1150
1151 /* wait for complete transmission of current pdu */
1152 while (wait_event_interruptible(so->wait, so->tx.state == ISOTP_IDLE) == 0 &&
1153 cmpxchg(&so->tx.state, ISOTP_IDLE, ISOTP_SHUTDOWN) != ISOTP_IDLE)
1154 ;
1155
1156 /* force state machines to be idle also when a signal occurred */
1157 so->tx.state = ISOTP_SHUTDOWN;
1158 so->rx.state = ISOTP_IDLE;
1159
1160 spin_lock(&isotp_notifier_lock);
1161 while (isotp_busy_notifier == so) {
1162 spin_unlock(&isotp_notifier_lock);
1163 schedule_timeout_uninterruptible(1);
1164 spin_lock(&isotp_notifier_lock);
1165 }
1166 list_del(&so->notifier);
1167 spin_unlock(&isotp_notifier_lock);
1168
1169 lock_sock(sk);
1170
1171 /* remove current filters & unregister */
1172 if (so->bound) {
1173 if (so->ifindex) {
1174 struct net_device *dev;
1175
1176 dev = dev_get_by_index(net, so->ifindex);
1177 if (dev) {
1178 if (isotp_register_rxid(so))
1179 can_rx_unregister(net, dev, so->rxid,
1180 SINGLE_MASK(so->rxid),
1181 isotp_rcv, sk);
1182
1183 can_rx_unregister(net, dev, so->txid,
1184 SINGLE_MASK(so->txid),
1185 isotp_rcv_echo, sk);
1186 dev_put(dev);
1187 synchronize_rcu();
1188 }
1189 }
1190 }
1191
1192 hrtimer_cancel(&so->txfrtimer);
1193 hrtimer_cancel(&so->txtimer);
1194 hrtimer_cancel(&so->rxtimer);
1195
1196 so->ifindex = 0;
1197 so->bound = 0;
1198
1199 sock_orphan(sk);
1200 sock->sk = NULL;
1201
1202 release_sock(sk);
1203 sock_put(sk);
1204
1205 return 0;
1206 }
1207
isotp_bind(struct socket * sock,struct sockaddr * uaddr,int len)1208 static int isotp_bind(struct socket *sock, struct sockaddr *uaddr, int len)
1209 {
1210 struct sockaddr_can *addr = (struct sockaddr_can *)uaddr;
1211 struct sock *sk = sock->sk;
1212 struct isotp_sock *so = isotp_sk(sk);
1213 struct net *net = sock_net(sk);
1214 int ifindex;
1215 struct net_device *dev;
1216 canid_t tx_id = addr->can_addr.tp.tx_id;
1217 canid_t rx_id = addr->can_addr.tp.rx_id;
1218 int err = 0;
1219 int notify_enetdown = 0;
1220
1221 if (len < ISOTP_MIN_NAMELEN)
1222 return -EINVAL;
1223
1224 if (addr->can_family != AF_CAN)
1225 return -EINVAL;
1226
1227 /* sanitize tx CAN identifier */
1228 if (tx_id & CAN_EFF_FLAG)
1229 tx_id &= (CAN_EFF_FLAG | CAN_EFF_MASK);
1230 else
1231 tx_id &= CAN_SFF_MASK;
1232
1233 /* give feedback on wrong CAN-ID value */
1234 if (tx_id != addr->can_addr.tp.tx_id)
1235 return -EINVAL;
1236
1237 /* sanitize rx CAN identifier (if needed) */
1238 if (isotp_register_rxid(so)) {
1239 if (rx_id & CAN_EFF_FLAG)
1240 rx_id &= (CAN_EFF_FLAG | CAN_EFF_MASK);
1241 else
1242 rx_id &= CAN_SFF_MASK;
1243
1244 /* give feedback on wrong CAN-ID value */
1245 if (rx_id != addr->can_addr.tp.rx_id)
1246 return -EINVAL;
1247 }
1248
1249 if (!addr->can_ifindex)
1250 return -ENODEV;
1251
1252 lock_sock(sk);
1253
1254 if (so->bound) {
1255 err = -EINVAL;
1256 goto out;
1257 }
1258
1259 /* ensure different CAN IDs when the rx_id is to be registered */
1260 if (isotp_register_rxid(so) && rx_id == tx_id) {
1261 err = -EADDRNOTAVAIL;
1262 goto out;
1263 }
1264
1265 dev = dev_get_by_index(net, addr->can_ifindex);
1266 if (!dev) {
1267 err = -ENODEV;
1268 goto out;
1269 }
1270 if (dev->type != ARPHRD_CAN) {
1271 dev_put(dev);
1272 err = -ENODEV;
1273 goto out;
1274 }
1275 if (dev->mtu < so->ll.mtu) {
1276 dev_put(dev);
1277 err = -EINVAL;
1278 goto out;
1279 }
1280 if (!(dev->flags & IFF_UP))
1281 notify_enetdown = 1;
1282
1283 ifindex = dev->ifindex;
1284
1285 if (isotp_register_rxid(so))
1286 can_rx_register(net, dev, rx_id, SINGLE_MASK(rx_id),
1287 isotp_rcv, sk, "isotp", sk);
1288
1289 /* no consecutive frame echo skb in flight */
1290 so->cfecho = 0;
1291
1292 /* register for echo skb's */
1293 can_rx_register(net, dev, tx_id, SINGLE_MASK(tx_id),
1294 isotp_rcv_echo, sk, "isotpe", sk);
1295
1296 dev_put(dev);
1297
1298 /* switch to new settings */
1299 so->ifindex = ifindex;
1300 so->rxid = rx_id;
1301 so->txid = tx_id;
1302 so->bound = 1;
1303
1304 out:
1305 release_sock(sk);
1306
1307 if (notify_enetdown) {
1308 sk->sk_err = ENETDOWN;
1309 if (!sock_flag(sk, SOCK_DEAD))
1310 sk->sk_error_report(sk);
1311 }
1312
1313 return err;
1314 }
1315
isotp_getname(struct socket * sock,struct sockaddr * uaddr,int peer)1316 static int isotp_getname(struct socket *sock, struct sockaddr *uaddr, int peer)
1317 {
1318 struct sockaddr_can *addr = (struct sockaddr_can *)uaddr;
1319 struct sock *sk = sock->sk;
1320 struct isotp_sock *so = isotp_sk(sk);
1321
1322 if (peer)
1323 return -EOPNOTSUPP;
1324
1325 memset(addr, 0, ISOTP_MIN_NAMELEN);
1326 addr->can_family = AF_CAN;
1327 addr->can_ifindex = so->ifindex;
1328 addr->can_addr.tp.rx_id = so->rxid;
1329 addr->can_addr.tp.tx_id = so->txid;
1330
1331 return ISOTP_MIN_NAMELEN;
1332 }
1333
isotp_setsockopt_locked(struct socket * sock,int level,int optname,sockptr_t optval,unsigned int optlen)1334 static int isotp_setsockopt_locked(struct socket *sock, int level, int optname,
1335 sockptr_t optval, unsigned int optlen)
1336 {
1337 struct sock *sk = sock->sk;
1338 struct isotp_sock *so = isotp_sk(sk);
1339 int ret = 0;
1340
1341 if (so->bound)
1342 return -EISCONN;
1343
1344 switch (optname) {
1345 case CAN_ISOTP_OPTS:
1346 if (optlen != sizeof(struct can_isotp_options))
1347 return -EINVAL;
1348
1349 if (copy_from_sockptr(&so->opt, optval, optlen))
1350 return -EFAULT;
1351
1352 /* no separate rx_ext_address is given => use ext_address */
1353 if (!(so->opt.flags & CAN_ISOTP_RX_EXT_ADDR))
1354 so->opt.rx_ext_address = so->opt.ext_address;
1355
1356 /* these broadcast flags are not allowed together */
1357 if (isotp_bc_flags(so) == ISOTP_ALL_BC_FLAGS) {
1358 /* CAN_ISOTP_SF_BROADCAST is prioritized */
1359 so->opt.flags &= ~CAN_ISOTP_CF_BROADCAST;
1360
1361 /* give user feedback on wrong config attempt */
1362 ret = -EINVAL;
1363 }
1364
1365 /* check for frame_txtime changes (0 => no changes) */
1366 if (so->opt.frame_txtime) {
1367 if (so->opt.frame_txtime == CAN_ISOTP_FRAME_TXTIME_ZERO)
1368 so->frame_txtime = 0;
1369 else
1370 so->frame_txtime = so->opt.frame_txtime;
1371 }
1372 break;
1373
1374 case CAN_ISOTP_RECV_FC:
1375 if (optlen != sizeof(struct can_isotp_fc_options))
1376 return -EINVAL;
1377
1378 if (copy_from_sockptr(&so->rxfc, optval, optlen))
1379 return -EFAULT;
1380 break;
1381
1382 case CAN_ISOTP_TX_STMIN:
1383 if (optlen != sizeof(u32))
1384 return -EINVAL;
1385
1386 if (copy_from_sockptr(&so->force_tx_stmin, optval, optlen))
1387 return -EFAULT;
1388 break;
1389
1390 case CAN_ISOTP_RX_STMIN:
1391 if (optlen != sizeof(u32))
1392 return -EINVAL;
1393
1394 if (copy_from_sockptr(&so->force_rx_stmin, optval, optlen))
1395 return -EFAULT;
1396 break;
1397
1398 case CAN_ISOTP_LL_OPTS:
1399 if (optlen == sizeof(struct can_isotp_ll_options)) {
1400 struct can_isotp_ll_options ll;
1401
1402 if (copy_from_sockptr(&ll, optval, optlen))
1403 return -EFAULT;
1404
1405 /* check for correct ISO 11898-1 DLC data length */
1406 if (ll.tx_dl != padlen(ll.tx_dl))
1407 return -EINVAL;
1408
1409 if (ll.mtu != CAN_MTU && ll.mtu != CANFD_MTU)
1410 return -EINVAL;
1411
1412 if (ll.mtu == CAN_MTU &&
1413 (ll.tx_dl > CAN_MAX_DLEN || ll.tx_flags != 0))
1414 return -EINVAL;
1415
1416 memcpy(&so->ll, &ll, sizeof(ll));
1417
1418 /* set ll_dl for tx path to similar place as for rx */
1419 so->tx.ll_dl = ll.tx_dl;
1420 } else {
1421 return -EINVAL;
1422 }
1423 break;
1424
1425 default:
1426 ret = -ENOPROTOOPT;
1427 }
1428
1429 return ret;
1430 }
1431
isotp_setsockopt(struct socket * sock,int level,int optname,sockptr_t optval,unsigned int optlen)1432 static int isotp_setsockopt(struct socket *sock, int level, int optname,
1433 sockptr_t optval, unsigned int optlen)
1434
1435 {
1436 struct sock *sk = sock->sk;
1437 int ret;
1438
1439 if (level != SOL_CAN_ISOTP)
1440 return -EINVAL;
1441
1442 lock_sock(sk);
1443 ret = isotp_setsockopt_locked(sock, level, optname, optval, optlen);
1444 release_sock(sk);
1445 return ret;
1446 }
1447
isotp_getsockopt(struct socket * sock,int level,int optname,char __user * optval,int __user * optlen)1448 static int isotp_getsockopt(struct socket *sock, int level, int optname,
1449 char __user *optval, int __user *optlen)
1450 {
1451 struct sock *sk = sock->sk;
1452 struct isotp_sock *so = isotp_sk(sk);
1453 int len;
1454 void *val;
1455
1456 if (level != SOL_CAN_ISOTP)
1457 return -EINVAL;
1458 if (get_user(len, optlen))
1459 return -EFAULT;
1460 if (len < 0)
1461 return -EINVAL;
1462
1463 switch (optname) {
1464 case CAN_ISOTP_OPTS:
1465 len = min_t(int, len, sizeof(struct can_isotp_options));
1466 val = &so->opt;
1467 break;
1468
1469 case CAN_ISOTP_RECV_FC:
1470 len = min_t(int, len, sizeof(struct can_isotp_fc_options));
1471 val = &so->rxfc;
1472 break;
1473
1474 case CAN_ISOTP_TX_STMIN:
1475 len = min_t(int, len, sizeof(u32));
1476 val = &so->force_tx_stmin;
1477 break;
1478
1479 case CAN_ISOTP_RX_STMIN:
1480 len = min_t(int, len, sizeof(u32));
1481 val = &so->force_rx_stmin;
1482 break;
1483
1484 case CAN_ISOTP_LL_OPTS:
1485 len = min_t(int, len, sizeof(struct can_isotp_ll_options));
1486 val = &so->ll;
1487 break;
1488
1489 default:
1490 return -ENOPROTOOPT;
1491 }
1492
1493 if (put_user(len, optlen))
1494 return -EFAULT;
1495 if (copy_to_user(optval, val, len))
1496 return -EFAULT;
1497 return 0;
1498 }
1499
isotp_notify(struct isotp_sock * so,unsigned long msg,struct net_device * dev)1500 static void isotp_notify(struct isotp_sock *so, unsigned long msg,
1501 struct net_device *dev)
1502 {
1503 struct sock *sk = &so->sk;
1504
1505 if (!net_eq(dev_net(dev), sock_net(sk)))
1506 return;
1507
1508 if (so->ifindex != dev->ifindex)
1509 return;
1510
1511 switch (msg) {
1512 case NETDEV_UNREGISTER:
1513 lock_sock(sk);
1514 /* remove current filters & unregister */
1515 if (so->bound) {
1516 if (isotp_register_rxid(so))
1517 can_rx_unregister(dev_net(dev), dev, so->rxid,
1518 SINGLE_MASK(so->rxid),
1519 isotp_rcv, sk);
1520
1521 can_rx_unregister(dev_net(dev), dev, so->txid,
1522 SINGLE_MASK(so->txid),
1523 isotp_rcv_echo, sk);
1524 }
1525
1526 so->ifindex = 0;
1527 so->bound = 0;
1528 release_sock(sk);
1529
1530 sk->sk_err = ENODEV;
1531 if (!sock_flag(sk, SOCK_DEAD))
1532 sk->sk_error_report(sk);
1533 break;
1534
1535 case NETDEV_DOWN:
1536 sk->sk_err = ENETDOWN;
1537 if (!sock_flag(sk, SOCK_DEAD))
1538 sk->sk_error_report(sk);
1539 break;
1540 }
1541 }
1542
isotp_notifier(struct notifier_block * nb,unsigned long msg,void * ptr)1543 static int isotp_notifier(struct notifier_block *nb, unsigned long msg,
1544 void *ptr)
1545 {
1546 struct net_device *dev = netdev_notifier_info_to_dev(ptr);
1547
1548 if (dev->type != ARPHRD_CAN)
1549 return NOTIFY_DONE;
1550 if (msg != NETDEV_UNREGISTER && msg != NETDEV_DOWN)
1551 return NOTIFY_DONE;
1552 if (unlikely(isotp_busy_notifier)) /* Check for reentrant bug. */
1553 return NOTIFY_DONE;
1554
1555 spin_lock(&isotp_notifier_lock);
1556 list_for_each_entry(isotp_busy_notifier, &isotp_notifier_list, notifier) {
1557 spin_unlock(&isotp_notifier_lock);
1558 isotp_notify(isotp_busy_notifier, msg, dev);
1559 spin_lock(&isotp_notifier_lock);
1560 }
1561 isotp_busy_notifier = NULL;
1562 spin_unlock(&isotp_notifier_lock);
1563 return NOTIFY_DONE;
1564 }
1565
isotp_init(struct sock * sk)1566 static int isotp_init(struct sock *sk)
1567 {
1568 struct isotp_sock *so = isotp_sk(sk);
1569
1570 so->ifindex = 0;
1571 so->bound = 0;
1572
1573 so->opt.flags = CAN_ISOTP_DEFAULT_FLAGS;
1574 so->opt.ext_address = CAN_ISOTP_DEFAULT_EXT_ADDRESS;
1575 so->opt.rx_ext_address = CAN_ISOTP_DEFAULT_EXT_ADDRESS;
1576 so->opt.rxpad_content = CAN_ISOTP_DEFAULT_PAD_CONTENT;
1577 so->opt.txpad_content = CAN_ISOTP_DEFAULT_PAD_CONTENT;
1578 so->opt.frame_txtime = CAN_ISOTP_DEFAULT_FRAME_TXTIME;
1579 so->frame_txtime = CAN_ISOTP_DEFAULT_FRAME_TXTIME;
1580 so->rxfc.bs = CAN_ISOTP_DEFAULT_RECV_BS;
1581 so->rxfc.stmin = CAN_ISOTP_DEFAULT_RECV_STMIN;
1582 so->rxfc.wftmax = CAN_ISOTP_DEFAULT_RECV_WFTMAX;
1583 so->ll.mtu = CAN_ISOTP_DEFAULT_LL_MTU;
1584 so->ll.tx_dl = CAN_ISOTP_DEFAULT_LL_TX_DL;
1585 so->ll.tx_flags = CAN_ISOTP_DEFAULT_LL_TX_FLAGS;
1586
1587 /* set ll_dl for tx path to similar place as for rx */
1588 so->tx.ll_dl = so->ll.tx_dl;
1589
1590 so->rx.state = ISOTP_IDLE;
1591 so->tx.state = ISOTP_IDLE;
1592
1593 hrtimer_init(&so->rxtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_SOFT);
1594 so->rxtimer.function = isotp_rx_timer_handler;
1595 hrtimer_init(&so->txtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_SOFT);
1596 so->txtimer.function = isotp_tx_timer_handler;
1597 hrtimer_init(&so->txfrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_SOFT);
1598 so->txfrtimer.function = isotp_txfr_timer_handler;
1599
1600 init_waitqueue_head(&so->wait);
1601 spin_lock_init(&so->rx_lock);
1602
1603 spin_lock(&isotp_notifier_lock);
1604 list_add_tail(&so->notifier, &isotp_notifier_list);
1605 spin_unlock(&isotp_notifier_lock);
1606
1607 return 0;
1608 }
1609
isotp_poll(struct file * file,struct socket * sock,poll_table * wait)1610 static __poll_t isotp_poll(struct file *file, struct socket *sock, poll_table *wait)
1611 {
1612 struct sock *sk = sock->sk;
1613 struct isotp_sock *so = isotp_sk(sk);
1614
1615 __poll_t mask = datagram_poll(file, sock, wait);
1616 poll_wait(file, &so->wait, wait);
1617
1618 /* Check for false positives due to TX state */
1619 if ((mask & EPOLLWRNORM) && (so->tx.state != ISOTP_IDLE))
1620 mask &= ~(EPOLLOUT | EPOLLWRNORM);
1621
1622 return mask;
1623 }
1624
isotp_sock_no_ioctlcmd(struct socket * sock,unsigned int cmd,unsigned long arg)1625 static int isotp_sock_no_ioctlcmd(struct socket *sock, unsigned int cmd,
1626 unsigned long arg)
1627 {
1628 /* no ioctls for socket layer -> hand it down to NIC layer */
1629 return -ENOIOCTLCMD;
1630 }
1631
1632 static const struct proto_ops isotp_ops = {
1633 .family = PF_CAN,
1634 .release = isotp_release,
1635 .bind = isotp_bind,
1636 .connect = sock_no_connect,
1637 .socketpair = sock_no_socketpair,
1638 .accept = sock_no_accept,
1639 .getname = isotp_getname,
1640 .poll = isotp_poll,
1641 .ioctl = isotp_sock_no_ioctlcmd,
1642 .gettstamp = sock_gettstamp,
1643 .listen = sock_no_listen,
1644 .shutdown = sock_no_shutdown,
1645 .setsockopt = isotp_setsockopt,
1646 .getsockopt = isotp_getsockopt,
1647 .sendmsg = isotp_sendmsg,
1648 .recvmsg = isotp_recvmsg,
1649 .mmap = sock_no_mmap,
1650 .sendpage = sock_no_sendpage,
1651 };
1652
1653 static struct proto isotp_proto __read_mostly = {
1654 .name = "CAN_ISOTP",
1655 .owner = THIS_MODULE,
1656 .obj_size = sizeof(struct isotp_sock),
1657 .init = isotp_init,
1658 };
1659
1660 static const struct can_proto isotp_can_proto = {
1661 .type = SOCK_DGRAM,
1662 .protocol = CAN_ISOTP,
1663 .ops = &isotp_ops,
1664 .prot = &isotp_proto,
1665 };
1666
1667 static struct notifier_block canisotp_notifier = {
1668 .notifier_call = isotp_notifier
1669 };
1670
isotp_module_init(void)1671 static __init int isotp_module_init(void)
1672 {
1673 int err;
1674
1675 pr_info("can: isotp protocol\n");
1676
1677 err = can_proto_register(&isotp_can_proto);
1678 if (err < 0)
1679 pr_err("can: registration of isotp protocol failed %pe\n", ERR_PTR(err));
1680 else
1681 register_netdevice_notifier(&canisotp_notifier);
1682
1683 return err;
1684 }
1685
isotp_module_exit(void)1686 static __exit void isotp_module_exit(void)
1687 {
1688 can_proto_unregister(&isotp_can_proto);
1689 unregister_netdevice_notifier(&canisotp_notifier);
1690 }
1691
1692 module_init(isotp_module_init);
1693 module_exit(isotp_module_exit);
1694