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
75MODULE_DESCRIPTION("PF_CAN ISO 15765-2 transport protocol");
76MODULE_LICENSE("Dual BSD/GPL");
77MODULE_AUTHOR("Oliver Hartkopp <socketcan@hartkopp.net>");
78MODULE_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
100static unsigned int max_pdu_size __read_mostly = DEFAULT_MAX_PDU_SIZE;
101module_param(max_pdu_size, uint, 0444);
102MODULE_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
129enum {
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
138struct 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
150struct 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
172static LIST_HEAD(isotp_notifier_list);
173static DEFINE_SPINLOCK(isotp_notifier_lock);
174static struct isotp_sock *isotp_busy_notifier;
175
176static inline struct isotp_sock *isotp_sk(const struct sock *sk)
177{
178 return (struct isotp_sock *)sk;
179}
180
181static u32 isotp_bc_flags(struct isotp_sock *so)
182{
183 return so->opt.flags & ISOTP_ALL_BC_FLAGS;
184}
185
186static 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
192static 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, flag: 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
213static 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(size: so->ll.mtu + sizeof(struct can_skb_priv), priority: gfp_any());
222 if (!nskb)
223 return 1;
224
225 dev = dev_get_by_index(net: sock_net(sk), ifindex: so->ifindex);
226 if (!dev) {
227 kfree_skb(skb: nskb);
228 return 1;
229 }
230
231 can_skb_reserve(skb: nskb);
232 can_skb_prv(skb: nskb)->ifindex = dev->ifindex;
233 can_skb_prv(skb: nskb)->skbcnt = 0;
234
235 nskb->dev = dev;
236 can_skb_set_owner(skb: nskb, sk);
237 ncf = (struct canfd_frame *)nskb->data;
238 skb_put_zero(skb: nskb, len: 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(skb: nskb, loop: 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(secs: 0, nsecs: 0);
271
272 /* start rx timeout watchdog */
273 hrtimer_start(timer: &so->rxtimer, tim: ktime_set(ISOTP_FC_TIMEOUT, nsecs: 0),
274 mode: HRTIMER_MODE_REL_SOFT);
275 return 0;
276}
277
278static void isotp_rcv_skb(struct sk_buff *skb, struct sock *sk)
279{
280 struct sockaddr_can *addr = (struct sockaddr_can *)skb->cb;
281 enum skb_drop_reason reason;
282
283 BUILD_BUG_ON(sizeof(skb->cb) < sizeof(struct sockaddr_can));
284
285 memset(addr, 0, sizeof(*addr));
286 addr->can_family = AF_CAN;
287 addr->can_ifindex = skb->dev->ifindex;
288
289 if (sock_queue_rcv_skb_reason(sk, skb, reason: &reason) < 0)
290 sk_skb_reason_drop(sk, skb, reason);
291}
292
293static u8 padlen(u8 datalen)
294{
295 static const u8 plen[] = {
296 8, 8, 8, 8, 8, 8, 8, 8, 8, /* 0 - 8 */
297 12, 12, 12, 12, /* 9 - 12 */
298 16, 16, 16, 16, /* 13 - 16 */
299 20, 20, 20, 20, /* 17 - 20 */
300 24, 24, 24, 24, /* 21 - 24 */
301 32, 32, 32, 32, 32, 32, 32, 32, /* 25 - 32 */
302 48, 48, 48, 48, 48, 48, 48, 48, /* 33 - 40 */
303 48, 48, 48, 48, 48, 48, 48, 48 /* 41 - 48 */
304 };
305
306 if (datalen > 48)
307 return 64;
308
309 return plen[datalen];
310}
311
312/* check for length optimization and return 1/true when the check fails */
313static int check_optimized(struct canfd_frame *cf, int start_index)
314{
315 /* for CAN_DL <= 8 the start_index is equal to the CAN_DL as the
316 * padding would start at this point. E.g. if the padding would
317 * start at cf.data[7] cf->len has to be 7 to be optimal.
318 * Note: The data[] index starts with zero.
319 */
320 if (cf->len <= CAN_MAX_DLEN)
321 return (cf->len != start_index);
322
323 /* This relation is also valid in the non-linear DLC range, where
324 * we need to take care of the minimal next possible CAN_DL.
325 * The correct check would be (padlen(cf->len) != padlen(start_index)).
326 * But as cf->len can only take discrete values from 12, .., 64 at this
327 * point the padlen(cf->len) is always equal to cf->len.
328 */
329 return (cf->len != padlen(datalen: start_index));
330}
331
332/* check padding and return 1/true when the check fails */
333static int check_pad(struct isotp_sock *so, struct canfd_frame *cf,
334 int start_index, u8 content)
335{
336 int i;
337
338 /* no RX_PADDING value => check length of optimized frame length */
339 if (!(so->opt.flags & CAN_ISOTP_RX_PADDING)) {
340 if (so->opt.flags & CAN_ISOTP_CHK_PAD_LEN)
341 return check_optimized(cf, start_index);
342
343 /* no valid test against empty value => ignore frame */
344 return 1;
345 }
346
347 /* check datalength of correctly padded CAN frame */
348 if ((so->opt.flags & CAN_ISOTP_CHK_PAD_LEN) &&
349 cf->len != padlen(datalen: cf->len))
350 return 1;
351
352 /* check padding content */
353 if (so->opt.flags & CAN_ISOTP_CHK_PAD_DATA) {
354 for (i = start_index; i < cf->len; i++)
355 if (cf->data[i] != content)
356 return 1;
357 }
358 return 0;
359}
360
361static void isotp_send_cframe(struct isotp_sock *so);
362
363static int isotp_rcv_fc(struct isotp_sock *so, struct canfd_frame *cf, int ae)
364{
365 struct sock *sk = &so->sk;
366
367 if (so->tx.state != ISOTP_WAIT_FC &&
368 so->tx.state != ISOTP_WAIT_FIRST_FC)
369 return 0;
370
371 hrtimer_cancel(timer: &so->txtimer);
372
373 if ((cf->len < ae + FC_CONTENT_SZ) ||
374 ((so->opt.flags & ISOTP_CHECK_PADDING) &&
375 check_pad(so, cf, start_index: ae + FC_CONTENT_SZ, content: so->opt.rxpad_content))) {
376 /* malformed PDU - report 'not a data message' */
377 sk->sk_err = EBADMSG;
378 if (!sock_flag(sk, flag: SOCK_DEAD))
379 sk_error_report(sk);
380
381 so->tx.state = ISOTP_IDLE;
382 wake_up_interruptible(&so->wait);
383 return 1;
384 }
385
386 /* get static/dynamic communication params from first/every FC frame */
387 if (so->tx.state == ISOTP_WAIT_FIRST_FC ||
388 so->opt.flags & CAN_ISOTP_DYN_FC_PARMS) {
389 so->txfc.bs = cf->data[ae + 1];
390 so->txfc.stmin = cf->data[ae + 2];
391
392 /* fix wrong STmin values according spec */
393 if (so->txfc.stmin > 0x7F &&
394 (so->txfc.stmin < 0xF1 || so->txfc.stmin > 0xF9))
395 so->txfc.stmin = 0x7F;
396
397 so->tx_gap = ktime_set(secs: 0, nsecs: 0);
398 /* add transmission time for CAN frame N_As */
399 so->tx_gap = ktime_add_ns(so->tx_gap, so->frame_txtime);
400 /* add waiting time for consecutive frames N_Cs */
401 if (so->opt.flags & CAN_ISOTP_FORCE_TXSTMIN)
402 so->tx_gap = ktime_add_ns(so->tx_gap,
403 so->force_tx_stmin);
404 else if (so->txfc.stmin < 0x80)
405 so->tx_gap = ktime_add_ns(so->tx_gap,
406 so->txfc.stmin * 1000000);
407 else
408 so->tx_gap = ktime_add_ns(so->tx_gap,
409 (so->txfc.stmin - 0xF0)
410 * 100000);
411 so->tx.state = ISOTP_WAIT_FC;
412 }
413
414 switch (cf->data[ae] & 0x0F) {
415 case ISOTP_FC_CTS:
416 so->tx.bs = 0;
417 so->tx.state = ISOTP_SENDING;
418 /* send CF frame and enable echo timeout handling */
419 hrtimer_start(timer: &so->txtimer, tim: ktime_set(ISOTP_ECHO_TIMEOUT, nsecs: 0),
420 mode: HRTIMER_MODE_REL_SOFT);
421 isotp_send_cframe(so);
422 break;
423
424 case ISOTP_FC_WT:
425 /* start timer to wait for next FC frame */
426 hrtimer_start(timer: &so->txtimer, tim: ktime_set(ISOTP_FC_TIMEOUT, nsecs: 0),
427 mode: HRTIMER_MODE_REL_SOFT);
428 break;
429
430 case ISOTP_FC_OVFLW:
431 /* overflow on receiver side - report 'message too long' */
432 sk->sk_err = EMSGSIZE;
433 if (!sock_flag(sk, flag: SOCK_DEAD))
434 sk_error_report(sk);
435 fallthrough;
436
437 default:
438 /* stop this tx job */
439 so->tx.state = ISOTP_IDLE;
440 wake_up_interruptible(&so->wait);
441 }
442 return 0;
443}
444
445static int isotp_rcv_sf(struct sock *sk, struct canfd_frame *cf, int pcilen,
446 struct sk_buff *skb, int len)
447{
448 struct isotp_sock *so = isotp_sk(sk);
449 struct sk_buff *nskb;
450
451 hrtimer_cancel(timer: &so->rxtimer);
452 so->rx.state = ISOTP_IDLE;
453
454 if (!len || len > cf->len - pcilen)
455 return 1;
456
457 if ((so->opt.flags & ISOTP_CHECK_PADDING) &&
458 check_pad(so, cf, start_index: pcilen + len, content: so->opt.rxpad_content)) {
459 /* malformed PDU - report 'not a data message' */
460 sk->sk_err = EBADMSG;
461 if (!sock_flag(sk, flag: SOCK_DEAD))
462 sk_error_report(sk);
463 return 1;
464 }
465
466 nskb = alloc_skb(size: len, priority: gfp_any());
467 if (!nskb)
468 return 1;
469
470 memcpy(skb_put(nskb, len), &cf->data[pcilen], len);
471
472 nskb->tstamp = skb->tstamp;
473 nskb->dev = skb->dev;
474 isotp_rcv_skb(skb: nskb, sk);
475 return 0;
476}
477
478static int isotp_rcv_ff(struct sock *sk, struct canfd_frame *cf, int ae)
479{
480 struct isotp_sock *so = isotp_sk(sk);
481 int i;
482 int off;
483 int ff_pci_sz;
484
485 hrtimer_cancel(timer: &so->rxtimer);
486 so->rx.state = ISOTP_IDLE;
487
488 /* get the used sender LL_DL from the (first) CAN frame data length */
489 so->rx.ll_dl = padlen(datalen: cf->len);
490
491 /* the first frame has to use the entire frame up to LL_DL length */
492 if (cf->len != so->rx.ll_dl)
493 return 1;
494
495 /* get the FF_DL */
496 so->rx.len = (cf->data[ae] & 0x0F) << 8;
497 so->rx.len += cf->data[ae + 1];
498
499 /* Check for FF_DL escape sequence supporting 32 bit PDU length */
500 if (so->rx.len) {
501 ff_pci_sz = FF_PCI_SZ12;
502 } else {
503 /* FF_DL = 0 => get real length from next 4 bytes */
504 so->rx.len = cf->data[ae + 2] << 24;
505 so->rx.len += cf->data[ae + 3] << 16;
506 so->rx.len += cf->data[ae + 4] << 8;
507 so->rx.len += cf->data[ae + 5];
508 ff_pci_sz = FF_PCI_SZ32;
509 }
510
511 /* take care of a potential SF_DL ESC offset for TX_DL > 8 */
512 off = (so->rx.ll_dl > CAN_MAX_DLEN) ? 1 : 0;
513
514 if (so->rx.len + ae + off + ff_pci_sz < so->rx.ll_dl)
515 return 1;
516
517 /* PDU size > default => try max_pdu_size */
518 if (so->rx.len > so->rx.buflen && so->rx.buflen < max_pdu_size) {
519 u8 *newbuf = kmalloc(max_pdu_size, GFP_ATOMIC);
520
521 if (newbuf) {
522 so->rx.buf = newbuf;
523 so->rx.buflen = max_pdu_size;
524 }
525 }
526
527 if (so->rx.len > so->rx.buflen) {
528 /* send FC frame with overflow status */
529 isotp_send_fc(sk, ae, ISOTP_FC_OVFLW);
530 return 1;
531 }
532
533 /* copy the first received data bytes */
534 so->rx.idx = 0;
535 for (i = ae + ff_pci_sz; i < so->rx.ll_dl; i++)
536 so->rx.buf[so->rx.idx++] = cf->data[i];
537
538 /* initial setup for this pdu reception */
539 so->rx.sn = 1;
540 so->rx.state = ISOTP_WAIT_DATA;
541
542 /* no creation of flow control frames */
543 if (so->opt.flags & CAN_ISOTP_LISTEN_MODE)
544 return 0;
545
546 /* send our first FC frame */
547 isotp_send_fc(sk, ae, ISOTP_FC_CTS);
548 return 0;
549}
550
551static int isotp_rcv_cf(struct sock *sk, struct canfd_frame *cf, int ae,
552 struct sk_buff *skb)
553{
554 struct isotp_sock *so = isotp_sk(sk);
555 struct sk_buff *nskb;
556 int i;
557
558 if (so->rx.state != ISOTP_WAIT_DATA)
559 return 0;
560
561 /* drop if timestamp gap is less than force_rx_stmin nano secs */
562 if (so->opt.flags & CAN_ISOTP_FORCE_RXSTMIN) {
563 if (ktime_to_ns(ktime_sub(skb->tstamp, so->lastrxcf_tstamp)) <
564 so->force_rx_stmin)
565 return 0;
566
567 so->lastrxcf_tstamp = skb->tstamp;
568 }
569
570 hrtimer_cancel(timer: &so->rxtimer);
571
572 /* CFs are never longer than the FF */
573 if (cf->len > so->rx.ll_dl)
574 return 1;
575
576 /* CFs have usually the LL_DL length */
577 if (cf->len < so->rx.ll_dl) {
578 /* this is only allowed for the last CF */
579 if (so->rx.len - so->rx.idx > so->rx.ll_dl - ae - N_PCI_SZ)
580 return 1;
581 }
582
583 if ((cf->data[ae] & 0x0F) != so->rx.sn) {
584 /* wrong sn detected - report 'illegal byte sequence' */
585 sk->sk_err = EILSEQ;
586 if (!sock_flag(sk, flag: SOCK_DEAD))
587 sk_error_report(sk);
588
589 /* reset rx state */
590 so->rx.state = ISOTP_IDLE;
591 return 1;
592 }
593 so->rx.sn++;
594 so->rx.sn %= 16;
595
596 for (i = ae + N_PCI_SZ; i < cf->len; i++) {
597 so->rx.buf[so->rx.idx++] = cf->data[i];
598 if (so->rx.idx >= so->rx.len)
599 break;
600 }
601
602 if (so->rx.idx >= so->rx.len) {
603 /* we are done */
604 so->rx.state = ISOTP_IDLE;
605
606 if ((so->opt.flags & ISOTP_CHECK_PADDING) &&
607 check_pad(so, cf, start_index: i + 1, content: so->opt.rxpad_content)) {
608 /* malformed PDU - report 'not a data message' */
609 sk->sk_err = EBADMSG;
610 if (!sock_flag(sk, flag: SOCK_DEAD))
611 sk_error_report(sk);
612 return 1;
613 }
614
615 nskb = alloc_skb(size: so->rx.len, priority: gfp_any());
616 if (!nskb)
617 return 1;
618
619 memcpy(skb_put(nskb, so->rx.len), so->rx.buf,
620 so->rx.len);
621
622 nskb->tstamp = skb->tstamp;
623 nskb->dev = skb->dev;
624 isotp_rcv_skb(skb: nskb, sk);
625 return 0;
626 }
627
628 /* perform blocksize handling, if enabled */
629 if (!so->rxfc.bs || ++so->rx.bs < so->rxfc.bs) {
630 /* start rx timeout watchdog */
631 hrtimer_start(timer: &so->rxtimer, tim: ktime_set(ISOTP_FC_TIMEOUT, nsecs: 0),
632 mode: HRTIMER_MODE_REL_SOFT);
633 return 0;
634 }
635
636 /* no creation of flow control frames */
637 if (so->opt.flags & CAN_ISOTP_LISTEN_MODE)
638 return 0;
639
640 /* we reached the specified blocksize so->rxfc.bs */
641 isotp_send_fc(sk, ae, ISOTP_FC_CTS);
642 return 0;
643}
644
645static void isotp_rcv(struct sk_buff *skb, void *data)
646{
647 struct sock *sk = (struct sock *)data;
648 struct isotp_sock *so = isotp_sk(sk);
649 struct canfd_frame *cf;
650 int ae = (so->opt.flags & CAN_ISOTP_EXTEND_ADDR) ? 1 : 0;
651 u8 n_pci_type, sf_dl;
652
653 /* Strictly receive only frames with the configured MTU size
654 * => clear separation of CAN2.0 / CAN FD transport channels
655 */
656 if (skb->len != so->ll.mtu)
657 return;
658
659 cf = (struct canfd_frame *)skb->data;
660
661 /* if enabled: check reception of my configured extended address */
662 if (ae && cf->data[0] != so->opt.rx_ext_address)
663 return;
664
665 n_pci_type = cf->data[ae] & 0xF0;
666
667 /* Make sure the state changes and data structures stay consistent at
668 * CAN frame reception time. This locking is not needed in real world
669 * use cases but the inconsistency can be triggered with syzkaller.
670 */
671 spin_lock(lock: &so->rx_lock);
672
673 if (so->opt.flags & CAN_ISOTP_HALF_DUPLEX) {
674 /* check rx/tx path half duplex expectations */
675 if ((so->tx.state != ISOTP_IDLE && n_pci_type != N_PCI_FC) ||
676 (so->rx.state != ISOTP_IDLE && n_pci_type == N_PCI_FC))
677 goto out_unlock;
678 }
679
680 switch (n_pci_type) {
681 case N_PCI_FC:
682 /* tx path: flow control frame containing the FC parameters */
683 isotp_rcv_fc(so, cf, ae);
684 break;
685
686 case N_PCI_SF:
687 /* rx path: single frame
688 *
689 * As we do not have a rx.ll_dl configuration, we can only test
690 * if the CAN frames payload length matches the LL_DL == 8
691 * requirements - no matter if it's CAN 2.0 or CAN FD
692 */
693
694 /* get the SF_DL from the N_PCI byte */
695 sf_dl = cf->data[ae] & 0x0F;
696
697 if (cf->len <= CAN_MAX_DLEN) {
698 isotp_rcv_sf(sk, cf, SF_PCI_SZ4 + ae, skb, len: sf_dl);
699 } else {
700 if (can_is_canfd_skb(skb)) {
701 /* We have a CAN FD frame and CAN_DL is greater than 8:
702 * Only frames with the SF_DL == 0 ESC value are valid.
703 *
704 * If so take care of the increased SF PCI size
705 * (SF_PCI_SZ8) to point to the message content behind
706 * the extended SF PCI info and get the real SF_DL
707 * length value from the formerly first data byte.
708 */
709 if (sf_dl == 0)
710 isotp_rcv_sf(sk, cf, SF_PCI_SZ8 + ae, skb,
711 len: cf->data[SF_PCI_SZ4 + ae]);
712 }
713 }
714 break;
715
716 case N_PCI_FF:
717 /* rx path: first frame */
718 isotp_rcv_ff(sk, cf, ae);
719 break;
720
721 case N_PCI_CF:
722 /* rx path: consecutive frame */
723 isotp_rcv_cf(sk, cf, ae, skb);
724 break;
725 }
726
727out_unlock:
728 spin_unlock(lock: &so->rx_lock);
729}
730
731static void isotp_fill_dataframe(struct canfd_frame *cf, struct isotp_sock *so,
732 int ae, int off)
733{
734 int pcilen = N_PCI_SZ + ae + off;
735 int space = so->tx.ll_dl - pcilen;
736 int num = min_t(int, so->tx.len - so->tx.idx, space);
737 int i;
738
739 cf->can_id = so->txid;
740 cf->len = num + pcilen;
741
742 if (num < space) {
743 if (so->opt.flags & CAN_ISOTP_TX_PADDING) {
744 /* user requested padding */
745 cf->len = padlen(datalen: cf->len);
746 memset(cf->data, so->opt.txpad_content, cf->len);
747 } else if (cf->len > CAN_MAX_DLEN) {
748 /* mandatory padding for CAN FD frames */
749 cf->len = padlen(datalen: cf->len);
750 memset(cf->data, CAN_ISOTP_DEFAULT_PAD_CONTENT,
751 cf->len);
752 }
753 }
754
755 for (i = 0; i < num; i++)
756 cf->data[pcilen + i] = so->tx.buf[so->tx.idx++];
757
758 if (ae)
759 cf->data[0] = so->opt.ext_address;
760}
761
762static void isotp_send_cframe(struct isotp_sock *so)
763{
764 struct sock *sk = &so->sk;
765 struct sk_buff *skb;
766 struct net_device *dev;
767 struct canfd_frame *cf;
768 int can_send_ret;
769 int ae = (so->opt.flags & CAN_ISOTP_EXTEND_ADDR) ? 1 : 0;
770
771 dev = dev_get_by_index(net: sock_net(sk), ifindex: so->ifindex);
772 if (!dev)
773 return;
774
775 skb = alloc_skb(size: so->ll.mtu + sizeof(struct can_skb_priv), GFP_ATOMIC);
776 if (!skb) {
777 dev_put(dev);
778 return;
779 }
780
781 can_skb_reserve(skb);
782 can_skb_prv(skb)->ifindex = dev->ifindex;
783 can_skb_prv(skb)->skbcnt = 0;
784
785 cf = (struct canfd_frame *)skb->data;
786 skb_put_zero(skb, len: so->ll.mtu);
787
788 /* create consecutive frame */
789 isotp_fill_dataframe(cf, so, ae, off: 0);
790
791 /* place consecutive frame N_PCI in appropriate index */
792 cf->data[ae] = N_PCI_CF | so->tx.sn++;
793 so->tx.sn %= 16;
794 so->tx.bs++;
795
796 cf->flags = so->ll.tx_flags;
797
798 skb->dev = dev;
799 can_skb_set_owner(skb, sk);
800
801 /* cfecho should have been zero'ed by init/isotp_rcv_echo() */
802 if (so->cfecho)
803 pr_notice_once("can-isotp: cfecho is %08X != 0\n", so->cfecho);
804
805 /* set consecutive frame echo tag */
806 so->cfecho = *(u32 *)cf->data;
807
808 /* send frame with local echo enabled */
809 can_send_ret = can_send(skb, loop: 1);
810 if (can_send_ret) {
811 pr_notice_once("can-isotp: %s: can_send_ret %pe\n",
812 __func__, ERR_PTR(can_send_ret));
813 if (can_send_ret == -ENOBUFS)
814 pr_notice_once("can-isotp: tx queue is full\n");
815 }
816 dev_put(dev);
817}
818
819static void isotp_create_fframe(struct canfd_frame *cf, struct isotp_sock *so,
820 int ae)
821{
822 int i;
823 int ff_pci_sz;
824
825 cf->can_id = so->txid;
826 cf->len = so->tx.ll_dl;
827 if (ae)
828 cf->data[0] = so->opt.ext_address;
829
830 /* create N_PCI bytes with 12/32 bit FF_DL data length */
831 if (so->tx.len > MAX_12BIT_PDU_SIZE) {
832 /* use 32 bit FF_DL notation */
833 cf->data[ae] = N_PCI_FF;
834 cf->data[ae + 1] = 0;
835 cf->data[ae + 2] = (u8)(so->tx.len >> 24) & 0xFFU;
836 cf->data[ae + 3] = (u8)(so->tx.len >> 16) & 0xFFU;
837 cf->data[ae + 4] = (u8)(so->tx.len >> 8) & 0xFFU;
838 cf->data[ae + 5] = (u8)so->tx.len & 0xFFU;
839 ff_pci_sz = FF_PCI_SZ32;
840 } else {
841 /* use 12 bit FF_DL notation */
842 cf->data[ae] = (u8)(so->tx.len >> 8) | N_PCI_FF;
843 cf->data[ae + 1] = (u8)so->tx.len & 0xFFU;
844 ff_pci_sz = FF_PCI_SZ12;
845 }
846
847 /* add first data bytes depending on ae */
848 for (i = ae + ff_pci_sz; i < so->tx.ll_dl; i++)
849 cf->data[i] = so->tx.buf[so->tx.idx++];
850
851 so->tx.sn = 1;
852}
853
854static void isotp_rcv_echo(struct sk_buff *skb, void *data)
855{
856 struct sock *sk = (struct sock *)data;
857 struct isotp_sock *so = isotp_sk(sk);
858 struct canfd_frame *cf = (struct canfd_frame *)skb->data;
859
860 /* only handle my own local echo CF/SF skb's (no FF!) */
861 if (skb->sk != sk || so->cfecho != *(u32 *)cf->data)
862 return;
863
864 /* cancel local echo timeout */
865 hrtimer_cancel(timer: &so->txtimer);
866
867 /* local echo skb with consecutive frame has been consumed */
868 so->cfecho = 0;
869
870 if (so->tx.idx >= so->tx.len) {
871 /* we are done */
872 so->tx.state = ISOTP_IDLE;
873 wake_up_interruptible(&so->wait);
874 return;
875 }
876
877 if (so->txfc.bs && so->tx.bs >= so->txfc.bs) {
878 /* stop and wait for FC with timeout */
879 so->tx.state = ISOTP_WAIT_FC;
880 hrtimer_start(timer: &so->txtimer, tim: ktime_set(ISOTP_FC_TIMEOUT, nsecs: 0),
881 mode: HRTIMER_MODE_REL_SOFT);
882 return;
883 }
884
885 /* no gap between data frames needed => use burst mode */
886 if (!so->tx_gap) {
887 /* enable echo timeout handling */
888 hrtimer_start(timer: &so->txtimer, tim: ktime_set(ISOTP_ECHO_TIMEOUT, nsecs: 0),
889 mode: HRTIMER_MODE_REL_SOFT);
890 isotp_send_cframe(so);
891 return;
892 }
893
894 /* start timer to send next consecutive frame with correct delay */
895 hrtimer_start(timer: &so->txfrtimer, tim: so->tx_gap, mode: HRTIMER_MODE_REL_SOFT);
896}
897
898static enum hrtimer_restart isotp_tx_timer_handler(struct hrtimer *hrtimer)
899{
900 struct isotp_sock *so = container_of(hrtimer, struct isotp_sock,
901 txtimer);
902 struct sock *sk = &so->sk;
903
904 /* don't handle timeouts in IDLE or SHUTDOWN state */
905 if (so->tx.state == ISOTP_IDLE || so->tx.state == ISOTP_SHUTDOWN)
906 return HRTIMER_NORESTART;
907
908 /* we did not get any flow control or echo frame in time */
909
910 /* report 'communication error on send' */
911 sk->sk_err = ECOMM;
912 if (!sock_flag(sk, flag: SOCK_DEAD))
913 sk_error_report(sk);
914
915 /* reset tx state */
916 so->tx.state = ISOTP_IDLE;
917 wake_up_interruptible(&so->wait);
918
919 return HRTIMER_NORESTART;
920}
921
922static enum hrtimer_restart isotp_txfr_timer_handler(struct hrtimer *hrtimer)
923{
924 struct isotp_sock *so = container_of(hrtimer, struct isotp_sock,
925 txfrtimer);
926
927 /* start echo timeout handling and cover below protocol error */
928 hrtimer_start(timer: &so->txtimer, tim: ktime_set(ISOTP_ECHO_TIMEOUT, nsecs: 0),
929 mode: HRTIMER_MODE_REL_SOFT);
930
931 /* cfecho should be consumed by isotp_rcv_echo() here */
932 if (so->tx.state == ISOTP_SENDING && !so->cfecho)
933 isotp_send_cframe(so);
934
935 return HRTIMER_NORESTART;
936}
937
938static int isotp_sendmsg(struct socket *sock, struct msghdr *msg, size_t size)
939{
940 struct sock *sk = sock->sk;
941 struct isotp_sock *so = isotp_sk(sk);
942 struct sk_buff *skb;
943 struct net_device *dev;
944 struct canfd_frame *cf;
945 int ae = (so->opt.flags & CAN_ISOTP_EXTEND_ADDR) ? 1 : 0;
946 int wait_tx_done = (so->opt.flags & CAN_ISOTP_WAIT_TX_DONE) ? 1 : 0;
947 s64 hrtimer_sec = ISOTP_ECHO_TIMEOUT;
948 int off;
949 int err;
950
951 if (!so->bound || so->tx.state == ISOTP_SHUTDOWN)
952 return -EADDRNOTAVAIL;
953
954 while (cmpxchg(&so->tx.state, ISOTP_IDLE, ISOTP_SENDING) != ISOTP_IDLE) {
955 /* we do not support multiple buffers - for now */
956 if (msg->msg_flags & MSG_DONTWAIT)
957 return -EAGAIN;
958
959 if (so->tx.state == ISOTP_SHUTDOWN)
960 return -EADDRNOTAVAIL;
961
962 /* wait for complete transmission of current pdu */
963 err = wait_event_interruptible(so->wait, so->tx.state == ISOTP_IDLE);
964 if (err)
965 goto err_event_drop;
966 }
967
968 /* PDU size > default => try max_pdu_size */
969 if (size > so->tx.buflen && so->tx.buflen < max_pdu_size) {
970 u8 *newbuf = kmalloc(max_pdu_size, GFP_KERNEL);
971
972 if (newbuf) {
973 so->tx.buf = newbuf;
974 so->tx.buflen = max_pdu_size;
975 }
976 }
977
978 if (!size || size > so->tx.buflen) {
979 err = -EINVAL;
980 goto err_out_drop;
981 }
982
983 /* take care of a potential SF_DL ESC offset for TX_DL > 8 */
984 off = (so->tx.ll_dl > CAN_MAX_DLEN) ? 1 : 0;
985
986 /* does the given data fit into a single frame for SF_BROADCAST? */
987 if ((isotp_bc_flags(so) == CAN_ISOTP_SF_BROADCAST) &&
988 (size > so->tx.ll_dl - SF_PCI_SZ4 - ae - off)) {
989 err = -EINVAL;
990 goto err_out_drop;
991 }
992
993 err = memcpy_from_msg(data: so->tx.buf, msg, len: size);
994 if (err < 0)
995 goto err_out_drop;
996
997 dev = dev_get_by_index(net: sock_net(sk), ifindex: so->ifindex);
998 if (!dev) {
999 err = -ENXIO;
1000 goto err_out_drop;
1001 }
1002
1003 skb = sock_alloc_send_skb(sk, size: so->ll.mtu + sizeof(struct can_skb_priv),
1004 noblock: msg->msg_flags & MSG_DONTWAIT, errcode: &err);
1005 if (!skb) {
1006 dev_put(dev);
1007 goto err_out_drop;
1008 }
1009
1010 can_skb_reserve(skb);
1011 can_skb_prv(skb)->ifindex = dev->ifindex;
1012 can_skb_prv(skb)->skbcnt = 0;
1013
1014 so->tx.len = size;
1015 so->tx.idx = 0;
1016
1017 cf = (struct canfd_frame *)skb->data;
1018 skb_put_zero(skb, len: so->ll.mtu);
1019
1020 /* cfecho should have been zero'ed by init / former isotp_rcv_echo() */
1021 if (so->cfecho)
1022 pr_notice_once("can-isotp: uninit cfecho %08X\n", so->cfecho);
1023
1024 /* check for single frame transmission depending on TX_DL */
1025 if (size <= so->tx.ll_dl - SF_PCI_SZ4 - ae - off) {
1026 /* The message size generally fits into a SingleFrame - good.
1027 *
1028 * SF_DL ESC offset optimization:
1029 *
1030 * When TX_DL is greater 8 but the message would still fit
1031 * into a 8 byte CAN frame, we can omit the offset.
1032 * This prevents a protocol caused length extension from
1033 * CAN_DL = 8 to CAN_DL = 12 due to the SF_SL ESC handling.
1034 */
1035 if (size <= CAN_MAX_DLEN - SF_PCI_SZ4 - ae)
1036 off = 0;
1037
1038 isotp_fill_dataframe(cf, so, ae, off);
1039
1040 /* place single frame N_PCI w/o length in appropriate index */
1041 cf->data[ae] = N_PCI_SF;
1042
1043 /* place SF_DL size value depending on the SF_DL ESC offset */
1044 if (off)
1045 cf->data[SF_PCI_SZ4 + ae] = size;
1046 else
1047 cf->data[ae] |= size;
1048
1049 /* set CF echo tag for isotp_rcv_echo() (SF-mode) */
1050 so->cfecho = *(u32 *)cf->data;
1051 } else {
1052 /* send first frame */
1053
1054 isotp_create_fframe(cf, so, ae);
1055
1056 if (isotp_bc_flags(so) == CAN_ISOTP_CF_BROADCAST) {
1057 /* set timer for FC-less operation (STmin = 0) */
1058 if (so->opt.flags & CAN_ISOTP_FORCE_TXSTMIN)
1059 so->tx_gap = ktime_set(secs: 0, nsecs: so->force_tx_stmin);
1060 else
1061 so->tx_gap = ktime_set(secs: 0, nsecs: so->frame_txtime);
1062
1063 /* disable wait for FCs due to activated block size */
1064 so->txfc.bs = 0;
1065
1066 /* set CF echo tag for isotp_rcv_echo() (CF-mode) */
1067 so->cfecho = *(u32 *)cf->data;
1068 } else {
1069 /* standard flow control check */
1070 so->tx.state = ISOTP_WAIT_FIRST_FC;
1071
1072 /* start timeout for FC */
1073 hrtimer_sec = ISOTP_FC_TIMEOUT;
1074
1075 /* no CF echo tag for isotp_rcv_echo() (FF-mode) */
1076 so->cfecho = 0;
1077 }
1078 }
1079
1080 hrtimer_start(timer: &so->txtimer, tim: ktime_set(secs: hrtimer_sec, nsecs: 0),
1081 mode: HRTIMER_MODE_REL_SOFT);
1082
1083 /* send the first or only CAN frame */
1084 cf->flags = so->ll.tx_flags;
1085
1086 skb->dev = dev;
1087 skb->sk = sk;
1088 err = can_send(skb, loop: 1);
1089 dev_put(dev);
1090 if (err) {
1091 pr_notice_once("can-isotp: %s: can_send_ret %pe\n",
1092 __func__, ERR_PTR(err));
1093
1094 /* no transmission -> no timeout monitoring */
1095 hrtimer_cancel(timer: &so->txtimer);
1096
1097 /* reset consecutive frame echo tag */
1098 so->cfecho = 0;
1099
1100 goto err_out_drop;
1101 }
1102
1103 if (wait_tx_done) {
1104 /* wait for complete transmission of current pdu */
1105 err = wait_event_interruptible(so->wait, so->tx.state == ISOTP_IDLE);
1106 if (err)
1107 goto err_event_drop;
1108
1109 err = sock_error(sk);
1110 if (err)
1111 return err;
1112 }
1113
1114 return size;
1115
1116err_event_drop:
1117 /* got signal: force tx state machine to be idle */
1118 so->tx.state = ISOTP_IDLE;
1119 hrtimer_cancel(timer: &so->txfrtimer);
1120 hrtimer_cancel(timer: &so->txtimer);
1121err_out_drop:
1122 /* drop this PDU and unlock a potential wait queue */
1123 so->tx.state = ISOTP_IDLE;
1124 wake_up_interruptible(&so->wait);
1125
1126 return err;
1127}
1128
1129static int isotp_recvmsg(struct socket *sock, struct msghdr *msg, size_t size,
1130 int flags)
1131{
1132 struct sock *sk = sock->sk;
1133 struct sk_buff *skb;
1134 struct isotp_sock *so = isotp_sk(sk);
1135 int ret = 0;
1136
1137 if (flags & ~(MSG_DONTWAIT | MSG_TRUNC | MSG_PEEK | MSG_CMSG_COMPAT))
1138 return -EINVAL;
1139
1140 if (!so->bound)
1141 return -EADDRNOTAVAIL;
1142
1143 skb = skb_recv_datagram(sk, flags, err: &ret);
1144 if (!skb)
1145 return ret;
1146
1147 if (size < skb->len)
1148 msg->msg_flags |= MSG_TRUNC;
1149 else
1150 size = skb->len;
1151
1152 ret = memcpy_to_msg(msg, data: skb->data, len: size);
1153 if (ret < 0)
1154 goto out_err;
1155
1156 sock_recv_cmsgs(msg, sk, skb);
1157
1158 if (msg->msg_name) {
1159 __sockaddr_check_size(ISOTP_MIN_NAMELEN);
1160 msg->msg_namelen = ISOTP_MIN_NAMELEN;
1161 memcpy(msg->msg_name, skb->cb, msg->msg_namelen);
1162 }
1163
1164 /* set length of return value */
1165 ret = (flags & MSG_TRUNC) ? skb->len : size;
1166
1167out_err:
1168 skb_free_datagram(sk, skb);
1169
1170 return ret;
1171}
1172
1173static int isotp_release(struct socket *sock)
1174{
1175 struct sock *sk = sock->sk;
1176 struct isotp_sock *so;
1177 struct net *net;
1178
1179 if (!sk)
1180 return 0;
1181
1182 so = isotp_sk(sk);
1183 net = sock_net(sk);
1184
1185 /* wait for complete transmission of current pdu */
1186 while (wait_event_interruptible(so->wait, so->tx.state == ISOTP_IDLE) == 0 &&
1187 cmpxchg(&so->tx.state, ISOTP_IDLE, ISOTP_SHUTDOWN) != ISOTP_IDLE)
1188 ;
1189
1190 /* force state machines to be idle also when a signal occurred */
1191 so->tx.state = ISOTP_SHUTDOWN;
1192 so->rx.state = ISOTP_IDLE;
1193
1194 spin_lock(lock: &isotp_notifier_lock);
1195 while (isotp_busy_notifier == so) {
1196 spin_unlock(lock: &isotp_notifier_lock);
1197 schedule_timeout_uninterruptible(timeout: 1);
1198 spin_lock(lock: &isotp_notifier_lock);
1199 }
1200 list_del(entry: &so->notifier);
1201 spin_unlock(lock: &isotp_notifier_lock);
1202
1203 lock_sock(sk);
1204
1205 /* remove current filters & unregister */
1206 if (so->bound) {
1207 if (so->ifindex) {
1208 struct net_device *dev;
1209
1210 dev = dev_get_by_index(net, ifindex: so->ifindex);
1211 if (dev) {
1212 if (isotp_register_rxid(so))
1213 can_rx_unregister(net, dev, can_id: so->rxid,
1214 SINGLE_MASK(so->rxid),
1215 func: isotp_rcv, data: sk);
1216
1217 can_rx_unregister(net, dev, can_id: so->txid,
1218 SINGLE_MASK(so->txid),
1219 func: isotp_rcv_echo, data: sk);
1220 dev_put(dev);
1221 synchronize_rcu();
1222 }
1223 }
1224 }
1225
1226 hrtimer_cancel(timer: &so->txfrtimer);
1227 hrtimer_cancel(timer: &so->txtimer);
1228 hrtimer_cancel(timer: &so->rxtimer);
1229
1230 so->ifindex = 0;
1231 so->bound = 0;
1232
1233 if (so->rx.buf != so->rx.sbuf)
1234 kfree(objp: so->rx.buf);
1235
1236 if (so->tx.buf != so->tx.sbuf)
1237 kfree(objp: so->tx.buf);
1238
1239 sock_orphan(sk);
1240 sock->sk = NULL;
1241
1242 release_sock(sk);
1243 sock_prot_inuse_add(net, prot: sk->sk_prot, val: -1);
1244 sock_put(sk);
1245
1246 return 0;
1247}
1248
1249static int isotp_bind(struct socket *sock, struct sockaddr_unsized *uaddr, int len)
1250{
1251 struct sockaddr_can *addr = (struct sockaddr_can *)uaddr;
1252 struct sock *sk = sock->sk;
1253 struct isotp_sock *so = isotp_sk(sk);
1254 struct net *net = sock_net(sk);
1255 int ifindex;
1256 struct net_device *dev;
1257 canid_t tx_id = addr->can_addr.tp.tx_id;
1258 canid_t rx_id = addr->can_addr.tp.rx_id;
1259 int err = 0;
1260 int notify_enetdown = 0;
1261
1262 if (len < ISOTP_MIN_NAMELEN)
1263 return -EINVAL;
1264
1265 if (addr->can_family != AF_CAN)
1266 return -EINVAL;
1267
1268 /* sanitize tx CAN identifier */
1269 if (tx_id & CAN_EFF_FLAG)
1270 tx_id &= (CAN_EFF_FLAG | CAN_EFF_MASK);
1271 else
1272 tx_id &= CAN_SFF_MASK;
1273
1274 /* give feedback on wrong CAN-ID value */
1275 if (tx_id != addr->can_addr.tp.tx_id)
1276 return -EINVAL;
1277
1278 /* sanitize rx CAN identifier (if needed) */
1279 if (isotp_register_rxid(so)) {
1280 if (rx_id & CAN_EFF_FLAG)
1281 rx_id &= (CAN_EFF_FLAG | CAN_EFF_MASK);
1282 else
1283 rx_id &= CAN_SFF_MASK;
1284
1285 /* give feedback on wrong CAN-ID value */
1286 if (rx_id != addr->can_addr.tp.rx_id)
1287 return -EINVAL;
1288 }
1289
1290 if (!addr->can_ifindex)
1291 return -ENODEV;
1292
1293 lock_sock(sk);
1294
1295 if (so->bound) {
1296 err = -EINVAL;
1297 goto out;
1298 }
1299
1300 /* ensure different CAN IDs when the rx_id is to be registered */
1301 if (isotp_register_rxid(so) && rx_id == tx_id) {
1302 err = -EADDRNOTAVAIL;
1303 goto out;
1304 }
1305
1306 dev = dev_get_by_index(net, ifindex: addr->can_ifindex);
1307 if (!dev) {
1308 err = -ENODEV;
1309 goto out;
1310 }
1311 if (dev->type != ARPHRD_CAN) {
1312 dev_put(dev);
1313 err = -ENODEV;
1314 goto out;
1315 }
1316 if (READ_ONCE(dev->mtu) < so->ll.mtu) {
1317 dev_put(dev);
1318 err = -EINVAL;
1319 goto out;
1320 }
1321 if (!(dev->flags & IFF_UP))
1322 notify_enetdown = 1;
1323
1324 ifindex = dev->ifindex;
1325
1326 if (isotp_register_rxid(so))
1327 can_rx_register(net, dev, can_id: rx_id, SINGLE_MASK(rx_id),
1328 func: isotp_rcv, data: sk, ident: "isotp", sk);
1329
1330 /* no consecutive frame echo skb in flight */
1331 so->cfecho = 0;
1332
1333 /* register for echo skb's */
1334 can_rx_register(net, dev, can_id: tx_id, SINGLE_MASK(tx_id),
1335 func: isotp_rcv_echo, data: sk, ident: "isotpe", sk);
1336
1337 dev_put(dev);
1338
1339 /* switch to new settings */
1340 so->ifindex = ifindex;
1341 so->rxid = rx_id;
1342 so->txid = tx_id;
1343 so->bound = 1;
1344
1345out:
1346 release_sock(sk);
1347
1348 if (notify_enetdown) {
1349 sk->sk_err = ENETDOWN;
1350 if (!sock_flag(sk, flag: SOCK_DEAD))
1351 sk_error_report(sk);
1352 }
1353
1354 return err;
1355}
1356
1357static int isotp_getname(struct socket *sock, struct sockaddr *uaddr, int peer)
1358{
1359 struct sockaddr_can *addr = (struct sockaddr_can *)uaddr;
1360 struct sock *sk = sock->sk;
1361 struct isotp_sock *so = isotp_sk(sk);
1362
1363 if (peer)
1364 return -EOPNOTSUPP;
1365
1366 memset(addr, 0, ISOTP_MIN_NAMELEN);
1367 addr->can_family = AF_CAN;
1368 addr->can_ifindex = so->ifindex;
1369 addr->can_addr.tp.rx_id = so->rxid;
1370 addr->can_addr.tp.tx_id = so->txid;
1371
1372 return ISOTP_MIN_NAMELEN;
1373}
1374
1375static int isotp_setsockopt_locked(struct socket *sock, int level, int optname,
1376 sockptr_t optval, unsigned int optlen)
1377{
1378 struct sock *sk = sock->sk;
1379 struct isotp_sock *so = isotp_sk(sk);
1380 int ret = 0;
1381
1382 if (so->bound)
1383 return -EISCONN;
1384
1385 switch (optname) {
1386 case CAN_ISOTP_OPTS:
1387 if (optlen != sizeof(struct can_isotp_options))
1388 return -EINVAL;
1389
1390 if (copy_from_sockptr(dst: &so->opt, src: optval, size: optlen))
1391 return -EFAULT;
1392
1393 /* no separate rx_ext_address is given => use ext_address */
1394 if (!(so->opt.flags & CAN_ISOTP_RX_EXT_ADDR))
1395 so->opt.rx_ext_address = so->opt.ext_address;
1396
1397 /* these broadcast flags are not allowed together */
1398 if (isotp_bc_flags(so) == ISOTP_ALL_BC_FLAGS) {
1399 /* CAN_ISOTP_SF_BROADCAST is prioritized */
1400 so->opt.flags &= ~CAN_ISOTP_CF_BROADCAST;
1401
1402 /* give user feedback on wrong config attempt */
1403 ret = -EINVAL;
1404 }
1405
1406 /* check for frame_txtime changes (0 => no changes) */
1407 if (so->opt.frame_txtime) {
1408 if (so->opt.frame_txtime == CAN_ISOTP_FRAME_TXTIME_ZERO)
1409 so->frame_txtime = 0;
1410 else
1411 so->frame_txtime = so->opt.frame_txtime;
1412 }
1413 break;
1414
1415 case CAN_ISOTP_RECV_FC:
1416 if (optlen != sizeof(struct can_isotp_fc_options))
1417 return -EINVAL;
1418
1419 if (copy_from_sockptr(dst: &so->rxfc, src: optval, size: optlen))
1420 return -EFAULT;
1421 break;
1422
1423 case CAN_ISOTP_TX_STMIN:
1424 if (optlen != sizeof(u32))
1425 return -EINVAL;
1426
1427 if (copy_from_sockptr(dst: &so->force_tx_stmin, src: optval, size: optlen))
1428 return -EFAULT;
1429 break;
1430
1431 case CAN_ISOTP_RX_STMIN:
1432 if (optlen != sizeof(u32))
1433 return -EINVAL;
1434
1435 if (copy_from_sockptr(dst: &so->force_rx_stmin, src: optval, size: optlen))
1436 return -EFAULT;
1437 break;
1438
1439 case CAN_ISOTP_LL_OPTS:
1440 if (optlen == sizeof(struct can_isotp_ll_options)) {
1441 struct can_isotp_ll_options ll;
1442
1443 if (copy_from_sockptr(dst: &ll, src: optval, size: optlen))
1444 return -EFAULT;
1445
1446 /* check for correct ISO 11898-1 DLC data length */
1447 if (ll.tx_dl != padlen(datalen: ll.tx_dl))
1448 return -EINVAL;
1449
1450 if (ll.mtu != CAN_MTU && ll.mtu != CANFD_MTU)
1451 return -EINVAL;
1452
1453 if (ll.mtu == CAN_MTU &&
1454 (ll.tx_dl > CAN_MAX_DLEN || ll.tx_flags != 0))
1455 return -EINVAL;
1456
1457 memcpy(&so->ll, &ll, sizeof(ll));
1458
1459 /* set ll_dl for tx path to similar place as for rx */
1460 so->tx.ll_dl = ll.tx_dl;
1461 } else {
1462 return -EINVAL;
1463 }
1464 break;
1465
1466 default:
1467 ret = -ENOPROTOOPT;
1468 }
1469
1470 return ret;
1471}
1472
1473static int isotp_setsockopt(struct socket *sock, int level, int optname,
1474 sockptr_t optval, unsigned int optlen)
1475
1476{
1477 struct sock *sk = sock->sk;
1478 int ret;
1479
1480 if (level != SOL_CAN_ISOTP)
1481 return -EINVAL;
1482
1483 lock_sock(sk);
1484 ret = isotp_setsockopt_locked(sock, level, optname, optval, optlen);
1485 release_sock(sk);
1486 return ret;
1487}
1488
1489static int isotp_getsockopt(struct socket *sock, int level, int optname,
1490 char __user *optval, int __user *optlen)
1491{
1492 struct sock *sk = sock->sk;
1493 struct isotp_sock *so = isotp_sk(sk);
1494 int len;
1495 void *val;
1496
1497 if (level != SOL_CAN_ISOTP)
1498 return -EINVAL;
1499 if (get_user(len, optlen))
1500 return -EFAULT;
1501 if (len < 0)
1502 return -EINVAL;
1503
1504 switch (optname) {
1505 case CAN_ISOTP_OPTS:
1506 len = min_t(int, len, sizeof(struct can_isotp_options));
1507 val = &so->opt;
1508 break;
1509
1510 case CAN_ISOTP_RECV_FC:
1511 len = min_t(int, len, sizeof(struct can_isotp_fc_options));
1512 val = &so->rxfc;
1513 break;
1514
1515 case CAN_ISOTP_TX_STMIN:
1516 len = min_t(int, len, sizeof(u32));
1517 val = &so->force_tx_stmin;
1518 break;
1519
1520 case CAN_ISOTP_RX_STMIN:
1521 len = min_t(int, len, sizeof(u32));
1522 val = &so->force_rx_stmin;
1523 break;
1524
1525 case CAN_ISOTP_LL_OPTS:
1526 len = min_t(int, len, sizeof(struct can_isotp_ll_options));
1527 val = &so->ll;
1528 break;
1529
1530 default:
1531 return -ENOPROTOOPT;
1532 }
1533
1534 if (put_user(len, optlen))
1535 return -EFAULT;
1536 if (copy_to_user(to: optval, from: val, n: len))
1537 return -EFAULT;
1538 return 0;
1539}
1540
1541static void isotp_notify(struct isotp_sock *so, unsigned long msg,
1542 struct net_device *dev)
1543{
1544 struct sock *sk = &so->sk;
1545
1546 if (!net_eq(net1: dev_net(dev), net2: sock_net(sk)))
1547 return;
1548
1549 if (so->ifindex != dev->ifindex)
1550 return;
1551
1552 switch (msg) {
1553 case NETDEV_UNREGISTER:
1554 lock_sock(sk);
1555 /* remove current filters & unregister */
1556 if (so->bound) {
1557 if (isotp_register_rxid(so))
1558 can_rx_unregister(net: dev_net(dev), dev, can_id: so->rxid,
1559 SINGLE_MASK(so->rxid),
1560 func: isotp_rcv, data: sk);
1561
1562 can_rx_unregister(net: dev_net(dev), dev, can_id: so->txid,
1563 SINGLE_MASK(so->txid),
1564 func: isotp_rcv_echo, data: sk);
1565 }
1566
1567 so->ifindex = 0;
1568 so->bound = 0;
1569 release_sock(sk);
1570
1571 sk->sk_err = ENODEV;
1572 if (!sock_flag(sk, flag: SOCK_DEAD))
1573 sk_error_report(sk);
1574 break;
1575
1576 case NETDEV_DOWN:
1577 sk->sk_err = ENETDOWN;
1578 if (!sock_flag(sk, flag: SOCK_DEAD))
1579 sk_error_report(sk);
1580 break;
1581 }
1582}
1583
1584static int isotp_notifier(struct notifier_block *nb, unsigned long msg,
1585 void *ptr)
1586{
1587 struct net_device *dev = netdev_notifier_info_to_dev(info: ptr);
1588
1589 if (dev->type != ARPHRD_CAN)
1590 return NOTIFY_DONE;
1591 if (msg != NETDEV_UNREGISTER && msg != NETDEV_DOWN)
1592 return NOTIFY_DONE;
1593 if (unlikely(isotp_busy_notifier)) /* Check for reentrant bug. */
1594 return NOTIFY_DONE;
1595
1596 spin_lock(lock: &isotp_notifier_lock);
1597 list_for_each_entry(isotp_busy_notifier, &isotp_notifier_list, notifier) {
1598 spin_unlock(lock: &isotp_notifier_lock);
1599 isotp_notify(so: isotp_busy_notifier, msg, dev);
1600 spin_lock(lock: &isotp_notifier_lock);
1601 }
1602 isotp_busy_notifier = NULL;
1603 spin_unlock(lock: &isotp_notifier_lock);
1604 return NOTIFY_DONE;
1605}
1606
1607static int isotp_init(struct sock *sk)
1608{
1609 struct isotp_sock *so = isotp_sk(sk);
1610
1611 so->ifindex = 0;
1612 so->bound = 0;
1613
1614 so->opt.flags = CAN_ISOTP_DEFAULT_FLAGS;
1615 so->opt.ext_address = CAN_ISOTP_DEFAULT_EXT_ADDRESS;
1616 so->opt.rx_ext_address = CAN_ISOTP_DEFAULT_EXT_ADDRESS;
1617 so->opt.rxpad_content = CAN_ISOTP_DEFAULT_PAD_CONTENT;
1618 so->opt.txpad_content = CAN_ISOTP_DEFAULT_PAD_CONTENT;
1619 so->opt.frame_txtime = CAN_ISOTP_DEFAULT_FRAME_TXTIME;
1620 so->frame_txtime = CAN_ISOTP_DEFAULT_FRAME_TXTIME;
1621 so->rxfc.bs = CAN_ISOTP_DEFAULT_RECV_BS;
1622 so->rxfc.stmin = CAN_ISOTP_DEFAULT_RECV_STMIN;
1623 so->rxfc.wftmax = CAN_ISOTP_DEFAULT_RECV_WFTMAX;
1624 so->ll.mtu = CAN_ISOTP_DEFAULT_LL_MTU;
1625 so->ll.tx_dl = CAN_ISOTP_DEFAULT_LL_TX_DL;
1626 so->ll.tx_flags = CAN_ISOTP_DEFAULT_LL_TX_FLAGS;
1627
1628 /* set ll_dl for tx path to similar place as for rx */
1629 so->tx.ll_dl = so->ll.tx_dl;
1630
1631 so->rx.state = ISOTP_IDLE;
1632 so->tx.state = ISOTP_IDLE;
1633
1634 so->rx.buf = so->rx.sbuf;
1635 so->tx.buf = so->tx.sbuf;
1636 so->rx.buflen = ARRAY_SIZE(so->rx.sbuf);
1637 so->tx.buflen = ARRAY_SIZE(so->tx.sbuf);
1638
1639 hrtimer_setup(timer: &so->rxtimer, function: isotp_rx_timer_handler, CLOCK_MONOTONIC, mode: HRTIMER_MODE_REL_SOFT);
1640 hrtimer_setup(timer: &so->txtimer, function: isotp_tx_timer_handler, CLOCK_MONOTONIC, mode: HRTIMER_MODE_REL_SOFT);
1641 hrtimer_setup(timer: &so->txfrtimer, function: isotp_txfr_timer_handler, CLOCK_MONOTONIC,
1642 mode: HRTIMER_MODE_REL_SOFT);
1643
1644 init_waitqueue_head(&so->wait);
1645 spin_lock_init(&so->rx_lock);
1646
1647 spin_lock(lock: &isotp_notifier_lock);
1648 list_add_tail(new: &so->notifier, head: &isotp_notifier_list);
1649 spin_unlock(lock: &isotp_notifier_lock);
1650
1651 return 0;
1652}
1653
1654static __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(filp: file, wait_address: &so->wait, p: 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
1669static 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
1676static 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
1696static 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
1703static 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
1710static struct notifier_block canisotp_notifier = {
1711 .notifier_call = isotp_notifier
1712};
1713
1714static __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(cp: &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(nb: &canisotp_notifier);
1728
1729 return err;
1730}
1731
1732static __exit void isotp_module_exit(void)
1733{
1734 can_proto_unregister(cp: &isotp_can_proto);
1735 unregister_netdevice_notifier(nb: &canisotp_notifier);
1736}
1737
1738module_init(isotp_module_init);
1739module_exit(isotp_module_exit);
1740

source code of linux/net/can/isotp.c