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/can.h>
73 #include <net/sock.h>
74 #include <net/net_namespace.h>
75
76 MODULE_DESCRIPTION("PF_CAN ISO 15765-2 transport protocol");
77 MODULE_LICENSE("Dual BSD/GPL");
78 MODULE_AUTHOR("Oliver Hartkopp <socketcan@hartkopp.net>");
79 MODULE_ALIAS("can-proto-6");
80
81 #define ISOTP_MIN_NAMELEN CAN_REQUIRED_SIZE(struct sockaddr_can, can_addr.tp)
82
83 #define SINGLE_MASK(id) (((id) & CAN_EFF_FLAG) ? \
84 (CAN_EFF_MASK | CAN_EFF_FLAG | CAN_RTR_FLAG) : \
85 (CAN_SFF_MASK | CAN_EFF_FLAG | CAN_RTR_FLAG))
86
87 /* Since ISO 15765-2:2016 the CAN isotp protocol supports more than 4095
88 * byte per ISO PDU as the FF_DL can take full 32 bit values (4 Gbyte).
89 * We would need some good concept to handle this between user space and
90 * kernel space. For now set the static buffer to something about 8 kbyte
91 * to be able to test this new functionality.
92 */
93 #define DEFAULT_MAX_PDU_SIZE 8300
94
95 /* maximum PDU size before ISO 15765-2:2016 extension was 4095 */
96 #define MAX_12BIT_PDU_SIZE 4095
97
98 /* limit the isotp pdu size from the optional module parameter to 1MByte */
99 #define MAX_PDU_SIZE (1025 * 1024U)
100
101 static unsigned int max_pdu_size __read_mostly = DEFAULT_MAX_PDU_SIZE;
102 module_param(max_pdu_size, uint, 0444);
103 MODULE_PARM_DESC(max_pdu_size, "maximum isotp pdu size (default "
104 __stringify(DEFAULT_MAX_PDU_SIZE) ")");
105
106 /* N_PCI type values in bits 7-4 of N_PCI bytes */
107 #define N_PCI_SF 0x00 /* single frame */
108 #define N_PCI_FF 0x10 /* first frame */
109 #define N_PCI_CF 0x20 /* consecutive frame */
110 #define N_PCI_FC 0x30 /* flow control */
111
112 #define N_PCI_SZ 1 /* size of the PCI byte #1 */
113 #define SF_PCI_SZ4 1 /* size of SingleFrame PCI including 4 bit SF_DL */
114 #define SF_PCI_SZ8 2 /* size of SingleFrame PCI including 8 bit SF_DL */
115 #define FF_PCI_SZ12 2 /* size of FirstFrame PCI including 12 bit FF_DL */
116 #define FF_PCI_SZ32 6 /* size of FirstFrame PCI including 32 bit FF_DL */
117 #define FC_CONTENT_SZ 3 /* flow control content size in byte (FS/BS/STmin) */
118
119 #define ISOTP_CHECK_PADDING (CAN_ISOTP_CHK_PAD_LEN | CAN_ISOTP_CHK_PAD_DATA)
120 #define ISOTP_ALL_BC_FLAGS (CAN_ISOTP_SF_BROADCAST | CAN_ISOTP_CF_BROADCAST)
121
122 /* Flow Status given in FC frame */
123 #define ISOTP_FC_CTS 0 /* clear to send */
124 #define ISOTP_FC_WT 1 /* wait */
125 #define ISOTP_FC_OVFLW 2 /* overflow */
126
127 #define ISOTP_FC_TIMEOUT 1 /* 1 sec */
128 #define ISOTP_ECHO_TIMEOUT 2 /* 2 secs */
129
130 /* so->tx_result[so->tx_gen % ISOTP_TX_RESULT_SLOTS] holds the packed value
131 * (err << ISOTP_TX_RESULT_GEN_BITS | gen) for each tx generation slot, so it
132 * can be handled with a single READ_ONCE()/WRITE_ONCE() access.
133 */
134 #define ISOTP_TX_RESULT_SLOTS 4
135 #define ISOTP_TX_RESULT_GEN_BITS 24
136 #define ISOTP_TX_RESULT_GEN_MASK ((1U << ISOTP_TX_RESULT_GEN_BITS) - 1)
137 #define ISOTP_TX_RESULT_ERR_MASK 0xFF
138
139 enum {
140 ISOTP_IDLE = 0,
141 ISOTP_WAIT_FIRST_FC,
142 ISOTP_WAIT_FC,
143 ISOTP_WAIT_DATA,
144 ISOTP_SENDING,
145 ISOTP_SHUTDOWN,
146 };
147
148 struct tpcon {
149 u8 *buf;
150 unsigned int buflen;
151 unsigned int len;
152 unsigned int idx;
153 u32 state;
154 u8 bs;
155 u8 sn;
156 u8 ll_dl;
157 u8 sbuf[DEFAULT_MAX_PDU_SIZE];
158 };
159
160 struct isotp_sock {
161 struct sock sk;
162 int bound;
163 int ifindex;
164 struct net_device *dev;
165 netdevice_tracker dev_tracker;
166 canid_t txid;
167 canid_t rxid;
168 ktime_t tx_gap;
169 ktime_t lastrxcf_tstamp;
170 struct hrtimer rxtimer, txtimer, txfrtimer, echotimer;
171 struct can_isotp_options opt;
172 struct can_isotp_fc_options rxfc, txfc;
173 struct can_isotp_ll_options ll;
174 u32 frame_txtime;
175 u32 force_tx_stmin;
176 u32 force_rx_stmin;
177 u32 cfecho; /* consecutive frame echo tag */
178 u32 tx_gen; /* transfer generation, increased per new tx transfer */
179 u32 tx_result[ISOTP_TX_RESULT_SLOTS]; /* per-generation result slots */
180 struct tpcon rx, tx;
181 struct list_head notifier;
182 wait_queue_head_t wait;
183 spinlock_t rx_lock; /* protect single thread state machine */
184 };
185
186 static LIST_HEAD(isotp_notifier_list);
187 static DEFINE_SPINLOCK(isotp_notifier_lock);
188 static struct isotp_sock *isotp_busy_notifier;
189
190 /* increase (24 bit) tx generation value */
isotp_inc_tx_gen(u32 gen)191 static u32 isotp_inc_tx_gen(u32 gen)
192 {
193 return (gen + 1) & ISOTP_TX_RESULT_GEN_MASK;
194 }
195
196 /* store 8 bit error and 24 bit tx generation values in packed u32 element */
isotp_pack_tx_result(u32 gen,int err)197 static u32 isotp_pack_tx_result(u32 gen, int err)
198 {
199 return gen | ((u32)err << ISOTP_TX_RESULT_GEN_BITS);
200 }
201
202 /* get the 24 bit tx generation value from the tx result */
isotp_get_tx_gen(u32 gen_err)203 static u32 isotp_get_tx_gen(u32 gen_err)
204 {
205 return gen_err & ISOTP_TX_RESULT_GEN_MASK;
206 }
207
208 /* get the 8 bit error value from the tx result */
isotp_get_tx_err(u32 gen_err)209 static u32 isotp_get_tx_err(u32 gen_err)
210 {
211 return (gen_err >> ISOTP_TX_RESULT_GEN_BITS) & ISOTP_TX_RESULT_ERR_MASK;
212 }
213
214 /* store transfer result in per-generation%4 so->tx_result[] slot */
isotp_set_tx_result(struct isotp_sock * so,u32 gen,int err)215 static void isotp_set_tx_result(struct isotp_sock *so, u32 gen, int err)
216 {
217 WRITE_ONCE(so->tx_result[gen % ISOTP_TX_RESULT_SLOTS],
218 isotp_pack_tx_result(gen, err));
219 }
220
221 /* fetch the result recorded for 'gen', as a (negative) errno (0 for success) */
isotp_get_tx_result(struct isotp_sock * so,u32 gen)222 static int isotp_get_tx_result(struct isotp_sock *so, u32 gen)
223 {
224 u32 result = READ_ONCE(so->tx_result[gen % ISOTP_TX_RESULT_SLOTS]);
225
226 if (isotp_get_tx_gen(result) != gen) {
227 pr_notice_once("can-isotp: tx_result[] slot reused before read\n");
228
229 /* report failure rather than risk a false success */
230 return -ECOMM;
231 }
232
233 return -(isotp_get_tx_err(result));
234 }
235
236 /* true if done, shut down or superseded ('gen' is no longer the active
237 * transfer). Reads tx.state first (acquire) so tx_gen/tx_result reads
238 * below see at least what that state write published (common sequence).
239 */
isotp_tx_gen_done(struct isotp_sock * so,u32 gen)240 static bool isotp_tx_gen_done(struct isotp_sock *so, u32 gen)
241 {
242 /* read tx.state first for the common sequence */
243 u32 state = smp_load_acquire(&so->tx.state);
244
245 return state == ISOTP_IDLE || state == ISOTP_SHUTDOWN ||
246 READ_ONCE(so->tx_gen) != gen;
247 }
248
isotp_sk(const struct sock * sk)249 static inline struct isotp_sock *isotp_sk(const struct sock *sk)
250 {
251 return (struct isotp_sock *)sk;
252 }
253
isotp_bc_flags(struct isotp_sock * so)254 static u32 isotp_bc_flags(struct isotp_sock *so)
255 {
256 return so->opt.flags & ISOTP_ALL_BC_FLAGS;
257 }
258
isotp_register_rxid(struct isotp_sock * so)259 static bool isotp_register_rxid(struct isotp_sock *so)
260 {
261 /* no broadcast modes => register rx_id for FC frame reception */
262 return (isotp_bc_flags(so) == 0);
263 }
264
isotp_rx_timer_handler(struct hrtimer * hrtimer)265 static enum hrtimer_restart isotp_rx_timer_handler(struct hrtimer *hrtimer)
266 {
267 struct isotp_sock *so = container_of(hrtimer, struct isotp_sock,
268 rxtimer);
269 struct sock *sk = &so->sk;
270
271 if (READ_ONCE(so->rx.state) == ISOTP_WAIT_DATA) {
272 /* we did not get new data frames in time */
273
274 /* report 'connection timed out' */
275 sk->sk_err = ETIMEDOUT;
276 if (!sock_flag(sk, SOCK_DEAD))
277 sk_error_report(sk);
278
279 /* reset rx state */
280 WRITE_ONCE(so->rx.state, ISOTP_IDLE);
281 }
282
283 return HRTIMER_NORESTART;
284 }
285
isotp_send_fc(struct sock * sk,int ae,u8 flowstatus)286 static int isotp_send_fc(struct sock *sk, int ae, u8 flowstatus)
287 {
288 struct net_device *dev;
289 struct sk_buff *nskb;
290 struct can_skb_ext *csx;
291 struct canfd_frame *ncf;
292 struct isotp_sock *so = isotp_sk(sk);
293 int can_send_ret;
294
295 nskb = alloc_skb(so->ll.mtu, gfp_any());
296 if (!nskb)
297 return 1;
298
299 csx = can_skb_ext_add(nskb);
300 if (!csx) {
301 kfree_skb(nskb);
302 return 1;
303 }
304
305 dev = dev_get_by_index(sock_net(sk), so->ifindex);
306 if (!dev) {
307 kfree_skb(nskb);
308 return 1;
309 }
310
311 csx->can_iif = dev->ifindex;
312 nskb->dev = dev;
313 can_skb_set_owner(nskb, sk);
314 ncf = (struct canfd_frame *)nskb->data;
315 skb_put_zero(nskb, so->ll.mtu);
316
317 /* create & send flow control reply */
318 ncf->can_id = so->txid;
319
320 if (so->opt.flags & CAN_ISOTP_TX_PADDING) {
321 memset(ncf->data, so->opt.txpad_content, CAN_MAX_DLEN);
322 ncf->len = CAN_MAX_DLEN;
323 } else {
324 ncf->len = ae + FC_CONTENT_SZ;
325 }
326
327 ncf->data[ae] = N_PCI_FC | flowstatus;
328 ncf->data[ae + 1] = so->rxfc.bs;
329 ncf->data[ae + 2] = so->rxfc.stmin;
330
331 if (ae)
332 ncf->data[0] = so->opt.ext_address;
333
334 ncf->flags = so->ll.tx_flags;
335
336 can_send_ret = can_send(nskb, 1);
337 if (can_send_ret)
338 pr_notice_once("can-isotp: %s: can_send_ret %pe\n",
339 __func__, ERR_PTR(can_send_ret));
340
341 dev_put(dev);
342
343 /* reset blocksize counter */
344 so->rx.bs = 0;
345
346 /* reset last CF frame rx timestamp for rx stmin enforcement */
347 so->lastrxcf_tstamp = ktime_set(0, 0);
348
349 /* start rx timeout watchdog */
350 hrtimer_start(&so->rxtimer, ktime_set(ISOTP_FC_TIMEOUT, 0),
351 HRTIMER_MODE_REL_SOFT);
352 return 0;
353 }
354
isotp_rcv_skb(struct sk_buff * skb,struct sock * sk)355 static void isotp_rcv_skb(struct sk_buff *skb, struct sock *sk)
356 {
357 struct sockaddr_can *addr = (struct sockaddr_can *)skb->cb;
358 enum skb_drop_reason reason;
359
360 BUILD_BUG_ON(sizeof(skb->cb) < sizeof(struct sockaddr_can));
361
362 memset(addr, 0, sizeof(*addr));
363 addr->can_family = AF_CAN;
364 addr->can_ifindex = skb->dev->ifindex;
365
366 reason = sock_queue_rcv_skb_reason(sk, skb);
367 if (reason)
368 sk_skb_reason_drop(sk, skb, reason);
369 }
370
padlen(u8 datalen)371 static u8 padlen(u8 datalen)
372 {
373 static const u8 plen[] = {
374 8, 8, 8, 8, 8, 8, 8, 8, 8, /* 0 - 8 */
375 12, 12, 12, 12, /* 9 - 12 */
376 16, 16, 16, 16, /* 13 - 16 */
377 20, 20, 20, 20, /* 17 - 20 */
378 24, 24, 24, 24, /* 21 - 24 */
379 32, 32, 32, 32, 32, 32, 32, 32, /* 25 - 32 */
380 48, 48, 48, 48, 48, 48, 48, 48, /* 33 - 40 */
381 48, 48, 48, 48, 48, 48, 48, 48 /* 41 - 48 */
382 };
383
384 if (datalen > 48)
385 return 64;
386
387 return plen[datalen];
388 }
389
390 /* check for length optimization and return 1/true when the check fails */
check_optimized(struct canfd_frame * cf,int start_index)391 static int check_optimized(struct canfd_frame *cf, int start_index)
392 {
393 /* for CAN_DL <= 8 the start_index is equal to the CAN_DL as the
394 * padding would start at this point. E.g. if the padding would
395 * start at cf.data[7] cf->len has to be 7 to be optimal.
396 * Note: The data[] index starts with zero.
397 */
398 if (cf->len <= CAN_MAX_DLEN)
399 return (cf->len != start_index);
400
401 /* This relation is also valid in the non-linear DLC range, where
402 * we need to take care of the minimal next possible CAN_DL.
403 * The correct check would be (padlen(cf->len) != padlen(start_index)).
404 * But as cf->len can only take discrete values from 12, .., 64 at this
405 * point the padlen(cf->len) is always equal to cf->len.
406 */
407 return (cf->len != padlen(start_index));
408 }
409
410 /* 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)411 static int check_pad(struct isotp_sock *so, struct canfd_frame *cf,
412 int start_index, u8 content)
413 {
414 int i;
415
416 /* no RX_PADDING value => check length of optimized frame length */
417 if (!(so->opt.flags & CAN_ISOTP_RX_PADDING)) {
418 if (so->opt.flags & CAN_ISOTP_CHK_PAD_LEN)
419 return check_optimized(cf, start_index);
420
421 /* no valid test against empty value => ignore frame */
422 return 1;
423 }
424
425 /* check datalength of correctly padded CAN frame */
426 if ((so->opt.flags & CAN_ISOTP_CHK_PAD_LEN) &&
427 cf->len != padlen(cf->len))
428 return 1;
429
430 /* check padding content */
431 if (so->opt.flags & CAN_ISOTP_CHK_PAD_DATA) {
432 for (i = start_index; i < cf->len; i++)
433 if (cf->data[i] != content)
434 return 1;
435 }
436 return 0;
437 }
438
439 static void isotp_send_cframe(struct isotp_sock *so);
440
isotp_rcv_fc(struct isotp_sock * so,struct canfd_frame * cf,int ae)441 static int isotp_rcv_fc(struct isotp_sock *so, struct canfd_frame *cf, int ae)
442 {
443 struct sock *sk = &so->sk;
444 int tx_err = EBADMSG; /* default for unknown FC status */
445
446 if (READ_ONCE(so->tx.state) != ISOTP_WAIT_FC &&
447 READ_ONCE(so->tx.state) != ISOTP_WAIT_FIRST_FC)
448 return 0;
449
450 hrtimer_cancel(&so->txtimer);
451
452 /* isotp_tx_timeout() may have given up on this job while
453 * hrtimer_cancel() above waited for it to finish => recheck
454 */
455 if (READ_ONCE(so->tx.state) != ISOTP_WAIT_FC &&
456 READ_ONCE(so->tx.state) != ISOTP_WAIT_FIRST_FC)
457 return 1;
458
459 if ((cf->len < ae + FC_CONTENT_SZ) ||
460 ((so->opt.flags & ISOTP_CHECK_PADDING) &&
461 check_pad(so, cf, ae + FC_CONTENT_SZ, so->opt.rxpad_content))) {
462 /* malformed PDU - report 'not a data message' */
463 sk->sk_err = EBADMSG;
464 if (!sock_flag(sk, SOCK_DEAD))
465 sk_error_report(sk);
466
467 isotp_set_tx_result(so, so->tx_gen, EBADMSG);
468 /* set to IDLE after publishing tx_result */
469 smp_store_release(&so->tx.state, ISOTP_IDLE);
470 wake_up_interruptible(&so->wait);
471 return 1;
472 }
473
474 /* get static/dynamic communication params from first/every FC frame */
475 if (READ_ONCE(so->tx.state) == ISOTP_WAIT_FIRST_FC ||
476 so->opt.flags & CAN_ISOTP_DYN_FC_PARMS) {
477 so->txfc.bs = cf->data[ae + 1];
478 so->txfc.stmin = cf->data[ae + 2];
479
480 /* fix wrong STmin values according spec */
481 if (so->txfc.stmin > 0x7F &&
482 (so->txfc.stmin < 0xF1 || so->txfc.stmin > 0xF9))
483 so->txfc.stmin = 0x7F;
484
485 so->tx_gap = ktime_set(0, 0);
486 /* add transmission time for CAN frame N_As */
487 so->tx_gap = ktime_add_ns(so->tx_gap, so->frame_txtime);
488 /* add waiting time for consecutive frames N_Cs */
489 if (so->opt.flags & CAN_ISOTP_FORCE_TXSTMIN)
490 so->tx_gap = ktime_add_ns(so->tx_gap,
491 so->force_tx_stmin);
492 else if (so->txfc.stmin < 0x80)
493 so->tx_gap = ktime_add_ns(so->tx_gap,
494 so->txfc.stmin * 1000000);
495 else
496 so->tx_gap = ktime_add_ns(so->tx_gap,
497 (so->txfc.stmin - 0xF0)
498 * 100000);
499 WRITE_ONCE(so->tx.state, ISOTP_WAIT_FC);
500 }
501
502 switch (cf->data[ae] & 0x0F) {
503 case ISOTP_FC_CTS:
504 so->tx.bs = 0;
505 WRITE_ONCE(so->tx.state, ISOTP_SENDING);
506 /* send CF frame and enable echo timeout handling */
507 hrtimer_start(&so->echotimer, ktime_set(ISOTP_ECHO_TIMEOUT, 0),
508 HRTIMER_MODE_REL_SOFT);
509 isotp_send_cframe(so);
510 break;
511
512 case ISOTP_FC_WT:
513 /* start timer to wait for next FC frame */
514 hrtimer_start(&so->txtimer, ktime_set(ISOTP_FC_TIMEOUT, 0),
515 HRTIMER_MODE_REL_SOFT);
516 break;
517
518 case ISOTP_FC_OVFLW:
519 /* overflow on receiver side - report 'message too long' */
520 tx_err = EMSGSIZE;
521 fallthrough;
522
523 default:
524 /* reserved/unknown flow status (tx_err defaults to EBADMSG) */
525
526 sk->sk_err = tx_err;
527 if (!sock_flag(sk, SOCK_DEAD))
528 sk_error_report(sk);
529
530 isotp_set_tx_result(so, so->tx_gen, tx_err);
531 /* set to IDLE after publishing tx_result */
532 smp_store_release(&so->tx.state, ISOTP_IDLE);
533 wake_up_interruptible(&so->wait);
534 }
535 return 0;
536 }
537
isotp_rcv_sf(struct sock * sk,struct canfd_frame * cf,int pcilen,struct sk_buff * skb,int len)538 static int isotp_rcv_sf(struct sock *sk, struct canfd_frame *cf, int pcilen,
539 struct sk_buff *skb, int len)
540 {
541 struct isotp_sock *so = isotp_sk(sk);
542 struct sk_buff *nskb;
543
544 hrtimer_cancel(&so->rxtimer);
545 WRITE_ONCE(so->rx.state, ISOTP_IDLE);
546
547 if (!len || len > cf->len - pcilen)
548 return 1;
549
550 if ((so->opt.flags & ISOTP_CHECK_PADDING) &&
551 check_pad(so, cf, pcilen + len, so->opt.rxpad_content)) {
552 /* malformed PDU - report 'not a data message' */
553 sk->sk_err = EBADMSG;
554 if (!sock_flag(sk, SOCK_DEAD))
555 sk_error_report(sk);
556 return 1;
557 }
558
559 nskb = alloc_skb(len, gfp_any());
560 if (!nskb)
561 return 1;
562
563 memcpy(skb_put(nskb, len), &cf->data[pcilen], len);
564
565 nskb->tstamp = skb->tstamp;
566 nskb->dev = skb->dev;
567 isotp_rcv_skb(nskb, sk);
568 return 0;
569 }
570
isotp_rcv_ff(struct sock * sk,struct canfd_frame * cf,int ae)571 static int isotp_rcv_ff(struct sock *sk, struct canfd_frame *cf, int ae)
572 {
573 struct isotp_sock *so = isotp_sk(sk);
574 int i;
575 int off;
576 int ff_pci_sz;
577
578 hrtimer_cancel(&so->rxtimer);
579 WRITE_ONCE(so->rx.state, ISOTP_IDLE);
580
581 /* get the used sender LL_DL from the (first) CAN frame data length */
582 so->rx.ll_dl = padlen(cf->len);
583
584 /* the first frame has to use the entire frame up to LL_DL length */
585 if (cf->len != so->rx.ll_dl)
586 return 1;
587
588 /* get the FF_DL */
589 so->rx.len = (cf->data[ae] & 0x0F) << 8;
590 so->rx.len += cf->data[ae + 1];
591
592 /* Check for FF_DL escape sequence supporting 32 bit PDU length */
593 if (so->rx.len) {
594 ff_pci_sz = FF_PCI_SZ12;
595 } else {
596 /* FF_DL = 0 => get real length from next 4 bytes */
597 so->rx.len = cf->data[ae + 2] << 24;
598 so->rx.len += cf->data[ae + 3] << 16;
599 so->rx.len += cf->data[ae + 4] << 8;
600 so->rx.len += cf->data[ae + 5];
601 ff_pci_sz = FF_PCI_SZ32;
602 }
603
604 /* take care of a potential SF_DL ESC offset for TX_DL > 8 */
605 off = (so->rx.ll_dl > CAN_MAX_DLEN) ? 1 : 0;
606
607 if (so->rx.len + ae + off + ff_pci_sz < so->rx.ll_dl)
608 return 1;
609
610 /* PDU size > default => try max_pdu_size */
611 if (so->rx.len > so->rx.buflen && so->rx.buflen < max_pdu_size) {
612 u8 *newbuf = kmalloc(max_pdu_size, GFP_ATOMIC);
613
614 if (newbuf) {
615 so->rx.buf = newbuf;
616 so->rx.buflen = max_pdu_size;
617 }
618 }
619
620 if (so->rx.len > so->rx.buflen) {
621 /* send FC frame with overflow status */
622 isotp_send_fc(sk, ae, ISOTP_FC_OVFLW);
623 return 1;
624 }
625
626 /* copy the first received data bytes */
627 so->rx.idx = 0;
628 for (i = ae + ff_pci_sz; i < so->rx.ll_dl; i++)
629 so->rx.buf[so->rx.idx++] = cf->data[i];
630
631 /* initial setup for this pdu reception */
632 so->rx.sn = 1;
633 WRITE_ONCE(so->rx.state, ISOTP_WAIT_DATA);
634
635 /* no creation of flow control frames */
636 if (so->opt.flags & CAN_ISOTP_LISTEN_MODE)
637 return 0;
638
639 /* send our first FC frame */
640 isotp_send_fc(sk, ae, ISOTP_FC_CTS);
641 return 0;
642 }
643
isotp_rcv_cf(struct sock * sk,struct canfd_frame * cf,int ae,struct sk_buff * skb)644 static int isotp_rcv_cf(struct sock *sk, struct canfd_frame *cf, int ae,
645 struct sk_buff *skb)
646 {
647 struct isotp_sock *so = isotp_sk(sk);
648 struct sk_buff *nskb;
649 int i;
650
651 if (READ_ONCE(so->rx.state) != ISOTP_WAIT_DATA)
652 return 0;
653
654 /* drop if timestamp gap is less than force_rx_stmin nano secs */
655 if (so->opt.flags & CAN_ISOTP_FORCE_RXSTMIN) {
656 if (ktime_to_ns(ktime_sub(skb->tstamp, so->lastrxcf_tstamp)) <
657 so->force_rx_stmin)
658 return 0;
659
660 so->lastrxcf_tstamp = skb->tstamp;
661 }
662
663 hrtimer_cancel(&so->rxtimer);
664
665 /* isotp_rx_timer_handler() may have raced us for so->rx.state
666 * while hrtimer_cancel() above waited for it to finish => recheck
667 */
668 if (READ_ONCE(so->rx.state) != ISOTP_WAIT_DATA)
669 return 1;
670
671 /* CFs are never longer than the FF */
672 if (cf->len > so->rx.ll_dl)
673 return 1;
674
675 /* CFs have usually the LL_DL length */
676 if (cf->len < so->rx.ll_dl) {
677 /* this is only allowed for the last CF */
678 if (so->rx.len - so->rx.idx > so->rx.ll_dl - ae - N_PCI_SZ)
679 return 1;
680 }
681
682 if ((cf->data[ae] & 0x0F) != so->rx.sn) {
683 /* wrong sn detected - report 'illegal byte sequence' */
684 sk->sk_err = EILSEQ;
685 if (!sock_flag(sk, SOCK_DEAD))
686 sk_error_report(sk);
687
688 /* reset rx state */
689 WRITE_ONCE(so->rx.state, ISOTP_IDLE);
690 return 1;
691 }
692 so->rx.sn++;
693 so->rx.sn %= 16;
694
695 for (i = ae + N_PCI_SZ; i < cf->len; i++) {
696 so->rx.buf[so->rx.idx++] = cf->data[i];
697 if (so->rx.idx >= so->rx.len)
698 break;
699 }
700
701 if (so->rx.idx >= so->rx.len) {
702 /* we are done */
703 WRITE_ONCE(so->rx.state, ISOTP_IDLE);
704
705 if ((so->opt.flags & ISOTP_CHECK_PADDING) &&
706 check_pad(so, cf, i + 1, so->opt.rxpad_content)) {
707 /* malformed PDU - report 'not a data message' */
708 sk->sk_err = EBADMSG;
709 if (!sock_flag(sk, SOCK_DEAD))
710 sk_error_report(sk);
711 return 1;
712 }
713
714 nskb = alloc_skb(so->rx.len, gfp_any());
715 if (!nskb)
716 return 1;
717
718 memcpy(skb_put(nskb, so->rx.len), so->rx.buf,
719 so->rx.len);
720
721 nskb->tstamp = skb->tstamp;
722 nskb->dev = skb->dev;
723 isotp_rcv_skb(nskb, sk);
724 return 0;
725 }
726
727 /* perform blocksize handling, if enabled */
728 if (!so->rxfc.bs || ++so->rx.bs < so->rxfc.bs) {
729 /* start rx timeout watchdog */
730 hrtimer_start(&so->rxtimer, ktime_set(ISOTP_FC_TIMEOUT, 0),
731 HRTIMER_MODE_REL_SOFT);
732 return 0;
733 }
734
735 /* no creation of flow control frames */
736 if (so->opt.flags & CAN_ISOTP_LISTEN_MODE)
737 return 0;
738
739 /* we reached the specified blocksize so->rxfc.bs */
740 isotp_send_fc(sk, ae, ISOTP_FC_CTS);
741 return 0;
742 }
743
isotp_rcv(struct sk_buff * skb,void * data)744 static void isotp_rcv(struct sk_buff *skb, void *data)
745 {
746 struct sock *sk = (struct sock *)data;
747 struct isotp_sock *so = isotp_sk(sk);
748 struct canfd_frame *cf;
749 int ae = (so->opt.flags & CAN_ISOTP_EXTEND_ADDR) ? 1 : 0;
750 u8 n_pci_type, sf_dl;
751
752 /* Strictly receive only frames with the configured MTU size
753 * => clear separation of CAN2.0 / CAN FD transport channels
754 */
755 if (skb->len != so->ll.mtu)
756 return;
757
758 cf = (struct canfd_frame *)skb->data;
759
760 /* if enabled: check reception of my configured extended address */
761 if (ae && cf->data[0] != so->opt.rx_ext_address)
762 return;
763
764 n_pci_type = cf->data[ae] & 0xF0;
765
766 /* Make sure the state changes and data structures stay consistent at
767 * CAN frame reception time. This locking is not needed in real world
768 * use cases but the inconsistency can be triggered with syzkaller.
769 */
770 spin_lock(&so->rx_lock);
771
772 if (so->opt.flags & CAN_ISOTP_HALF_DUPLEX) {
773 /* check rx/tx path half duplex expectations */
774 if ((READ_ONCE(so->tx.state) != ISOTP_IDLE &&
775 n_pci_type != N_PCI_FC) ||
776 (READ_ONCE(so->rx.state) != ISOTP_IDLE &&
777 n_pci_type == N_PCI_FC))
778 goto out_unlock;
779 }
780
781 switch (n_pci_type) {
782 case N_PCI_FC:
783 /* tx path: flow control frame containing the FC parameters */
784 isotp_rcv_fc(so, cf, ae);
785 break;
786
787 case N_PCI_SF:
788 /* rx path: single frame
789 *
790 * As we do not have a rx.ll_dl configuration, we can only test
791 * if the CAN frames payload length matches the LL_DL == 8
792 * requirements - no matter if it's CAN 2.0 or CAN FD
793 */
794
795 /* get the SF_DL from the N_PCI byte */
796 sf_dl = cf->data[ae] & 0x0F;
797
798 if (cf->len <= CAN_MAX_DLEN) {
799 isotp_rcv_sf(sk, cf, SF_PCI_SZ4 + ae, skb, sf_dl);
800 } else {
801 if (can_is_canfd_skb(skb)) {
802 /* We have a CAN FD frame and CAN_DL is greater than 8:
803 * Only frames with the SF_DL == 0 ESC value are valid.
804 *
805 * If so take care of the increased SF PCI size
806 * (SF_PCI_SZ8) to point to the message content behind
807 * the extended SF PCI info and get the real SF_DL
808 * length value from the formerly first data byte.
809 */
810 if (sf_dl == 0)
811 isotp_rcv_sf(sk, cf, SF_PCI_SZ8 + ae, skb,
812 cf->data[SF_PCI_SZ4 + ae]);
813 }
814 }
815 break;
816
817 case N_PCI_FF:
818 /* rx path: first frame */
819 isotp_rcv_ff(sk, cf, ae);
820 break;
821
822 case N_PCI_CF:
823 /* rx path: consecutive frame */
824 isotp_rcv_cf(sk, cf, ae, skb);
825 break;
826 }
827
828 out_unlock:
829 spin_unlock(&so->rx_lock);
830 }
831
isotp_fill_dataframe(struct canfd_frame * cf,struct isotp_sock * so,int ae,int off)832 static void isotp_fill_dataframe(struct canfd_frame *cf, struct isotp_sock *so,
833 int ae, int off)
834 {
835 int pcilen = N_PCI_SZ + ae + off;
836 int space = so->tx.ll_dl - pcilen;
837 int num = min_t(int, so->tx.len - so->tx.idx, space);
838 int i;
839
840 cf->can_id = so->txid;
841 cf->len = num + pcilen;
842
843 if (num < space) {
844 if (so->opt.flags & CAN_ISOTP_TX_PADDING) {
845 /* user requested padding */
846 cf->len = padlen(cf->len);
847 memset(cf->data, so->opt.txpad_content, cf->len);
848 } else if (cf->len > CAN_MAX_DLEN) {
849 /* mandatory padding for CAN FD frames */
850 cf->len = padlen(cf->len);
851 memset(cf->data, CAN_ISOTP_DEFAULT_PAD_CONTENT,
852 cf->len);
853 }
854 }
855
856 for (i = 0; i < num; i++)
857 cf->data[pcilen + i] = so->tx.buf[so->tx.idx++];
858
859 if (ae)
860 cf->data[0] = so->opt.ext_address;
861 }
862
isotp_send_cframe(struct isotp_sock * so)863 static void isotp_send_cframe(struct isotp_sock *so)
864 {
865 struct sock *sk = &so->sk;
866 struct sk_buff *skb;
867 struct can_skb_ext *csx;
868 struct net_device *dev;
869 struct canfd_frame *cf;
870 int can_send_ret;
871 int ae = (so->opt.flags & CAN_ISOTP_EXTEND_ADDR) ? 1 : 0;
872 u32 old_cfecho;
873
874 dev = dev_get_by_index(sock_net(sk), so->ifindex);
875 if (!dev)
876 return;
877
878 skb = alloc_skb(so->ll.mtu, GFP_ATOMIC);
879 if (!skb) {
880 dev_put(dev);
881 return;
882 }
883
884 csx = can_skb_ext_add(skb);
885 if (!csx) {
886 kfree_skb(skb);
887 netdev_put(dev, NULL);
888 return;
889 }
890
891 csx->can_iif = dev->ifindex;
892
893 /* set uid in tx skb to identify CF echo frames */
894 can_set_skb_uid(csx);
895
896 cf = (struct canfd_frame *)skb->data;
897 skb_put_zero(skb, so->ll.mtu);
898
899 /* create consecutive frame */
900 isotp_fill_dataframe(cf, so, ae, 0);
901
902 /* place consecutive frame N_PCI in appropriate index */
903 cf->data[ae] = N_PCI_CF | so->tx.sn++;
904 so->tx.sn %= 16;
905 so->tx.bs++;
906
907 cf->flags = so->ll.tx_flags;
908
909 skb->dev = dev;
910 can_skb_set_owner(skb, sk);
911
912 /* zero'ed by init/isotp_rcv_echo(); reached lock-free via
913 * isotp_txfr_timer_handler() too, so use READ_ONCE()/WRITE_ONCE()
914 */
915 old_cfecho = READ_ONCE(so->cfecho);
916 if (old_cfecho)
917 pr_notice_once("can-isotp: cfecho is %08X != 0\n", old_cfecho);
918
919 /* set consecutive frame echo tag */
920 WRITE_ONCE(so->cfecho, csx->can_skb_uid);
921
922 /* send frame with local echo enabled */
923 can_send_ret = can_send(skb, 1);
924 if (can_send_ret) {
925 pr_notice_once("can-isotp: %s: can_send_ret %pe\n",
926 __func__, ERR_PTR(can_send_ret));
927 if (can_send_ret == -ENOBUFS)
928 pr_notice_once("can-isotp: tx queue is full\n");
929 }
930 dev_put(dev);
931 }
932
isotp_create_fframe(struct canfd_frame * cf,struct isotp_sock * so,int ae)933 static void isotp_create_fframe(struct canfd_frame *cf, struct isotp_sock *so,
934 int ae)
935 {
936 int i;
937 int ff_pci_sz;
938
939 cf->can_id = so->txid;
940 cf->len = so->tx.ll_dl;
941 if (ae)
942 cf->data[0] = so->opt.ext_address;
943
944 /* create N_PCI bytes with 12/32 bit FF_DL data length */
945 if (so->tx.len > MAX_12BIT_PDU_SIZE) {
946 /* use 32 bit FF_DL notation */
947 cf->data[ae] = N_PCI_FF;
948 cf->data[ae + 1] = 0;
949 cf->data[ae + 2] = (u8)(so->tx.len >> 24) & 0xFFU;
950 cf->data[ae + 3] = (u8)(so->tx.len >> 16) & 0xFFU;
951 cf->data[ae + 4] = (u8)(so->tx.len >> 8) & 0xFFU;
952 cf->data[ae + 5] = (u8)so->tx.len & 0xFFU;
953 ff_pci_sz = FF_PCI_SZ32;
954 } else {
955 /* use 12 bit FF_DL notation */
956 cf->data[ae] = (u8)(so->tx.len >> 8) | N_PCI_FF;
957 cf->data[ae + 1] = (u8)so->tx.len & 0xFFU;
958 ff_pci_sz = FF_PCI_SZ12;
959 }
960
961 /* add first data bytes depending on ae */
962 for (i = ae + ff_pci_sz; i < so->tx.ll_dl; i++)
963 cf->data[i] = so->tx.buf[so->tx.idx++];
964
965 so->tx.sn = 1;
966 }
967
isotp_rcv_echo(struct sk_buff * skb,void * data)968 static void isotp_rcv_echo(struct sk_buff *skb, void *data)
969 {
970 struct sock *sk = (struct sock *)data;
971 struct isotp_sock *so = isotp_sk(sk);
972 struct can_skb_ext *csx = can_skb_ext_find(skb);
973
974 /* only handle my own local echo CF/SF skb's (no FF!) */
975 if (skb->sk != sk)
976 return;
977
978 if (WARN_ON_ONCE(!csx))
979 return;
980
981 /* unlike isotp_rcv_fc()/isotp_rcv_cf(), not already under so->rx_lock
982 * (no isotp_rcv() caller here), so take it ourselves
983 */
984 spin_lock(&so->rx_lock);
985
986 /* so->cfecho may since belong to a new transfer; recheck under lock */
987 if (READ_ONCE(so->cfecho) != csx->can_skb_uid)
988 goto out_unlock;
989
990 /* cancel local echo timeout */
991 hrtimer_cancel(&so->echotimer);
992
993 /* local echo skb with consecutive frame has been consumed */
994 WRITE_ONCE(so->cfecho, 0);
995
996 /* claiming a transfer also takes so->rx_lock, so a plain recheck
997 * is enough: so->tx.state can't have flipped to ISOTP_SENDING for
998 * a new claim while we're still in here
999 */
1000 if (READ_ONCE(so->tx.state) != ISOTP_SENDING)
1001 goto out_unlock;
1002
1003 if (so->tx.idx >= so->tx.len) {
1004 /* we are done */
1005
1006 isotp_set_tx_result(so, so->tx_gen, 0);
1007 /* set to IDLE after publishing tx_result */
1008 smp_store_release(&so->tx.state, ISOTP_IDLE);
1009 wake_up_interruptible(&so->wait);
1010 goto out_unlock;
1011 }
1012
1013 if (so->txfc.bs && so->tx.bs >= so->txfc.bs) {
1014 /* stop and wait for FC with timeout */
1015 WRITE_ONCE(so->tx.state, ISOTP_WAIT_FC);
1016 hrtimer_start(&so->txtimer, ktime_set(ISOTP_FC_TIMEOUT, 0),
1017 HRTIMER_MODE_REL_SOFT);
1018 goto out_unlock;
1019 }
1020
1021 /* no gap between data frames needed => use burst mode */
1022 if (!so->tx_gap) {
1023 /* enable echo timeout handling */
1024 hrtimer_start(&so->echotimer, ktime_set(ISOTP_ECHO_TIMEOUT, 0),
1025 HRTIMER_MODE_REL_SOFT);
1026 isotp_send_cframe(so);
1027 goto out_unlock;
1028 }
1029
1030 /* start timer to send next consecutive frame with correct delay */
1031 hrtimer_start(&so->txfrtimer, so->tx_gap, HRTIMER_MODE_REL_SOFT);
1032
1033 out_unlock:
1034 spin_unlock(&so->rx_lock);
1035 }
1036
1037 /* isotp_tx_timeout: we did not get any flow control or echo frame in time
1038 *
1039 * Shared by so->txtimer's and so->echotimer's callbacks. Both timers get
1040 * cancelled under so->rx_lock elsewhere, so this must stay lock-free.
1041 *
1042 * tx.state is acquired before tx_gen. Common sequence in isotp_tx_gen_done().
1043 * cmpxchg() only orders itself, not the two preceding loads.
1044 */
isotp_tx_timeout(struct isotp_sock * so)1045 static enum hrtimer_restart isotp_tx_timeout(struct isotp_sock *so)
1046 {
1047 struct sock *sk = &so->sk;
1048 /* read tx.state first for the common sequence */
1049 u32 old_state = smp_load_acquire(&so->tx.state);
1050 u32 gen = READ_ONCE(so->tx_gen);
1051
1052 /* don't handle timeouts in IDLE or SHUTDOWN state */
1053 if (old_state == ISOTP_IDLE || old_state == ISOTP_SHUTDOWN)
1054 return HRTIMER_NORESTART;
1055
1056 /* only claim the timeout if the state is still unchanged */
1057 if (cmpxchg(&so->tx.state, old_state, ISOTP_IDLE) != old_state)
1058 return HRTIMER_NORESTART;
1059
1060 /* detected timeout: report 'communication error on send' */
1061
1062 /* a stale read of this slot by a waiter still falls back to ECOMM */
1063 isotp_set_tx_result(so, gen, ECOMM);
1064
1065 sk->sk_err = ECOMM;
1066 if (!sock_flag(sk, SOCK_DEAD))
1067 sk_error_report(sk);
1068
1069 wake_up_interruptible(&so->wait);
1070
1071 return HRTIMER_NORESTART;
1072 }
1073
1074 /* so->txtimer: fires when a Flow Control frame does not arrive in time */
isotp_tx_timer_handler(struct hrtimer * hrtimer)1075 static enum hrtimer_restart isotp_tx_timer_handler(struct hrtimer *hrtimer)
1076 {
1077 struct isotp_sock *so = container_of(hrtimer, struct isotp_sock,
1078 txtimer);
1079
1080 return isotp_tx_timeout(so);
1081 }
1082
1083 /* so->echotimer: fires when a sent CF/SF's local echo does not arrive */
isotp_echo_timer_handler(struct hrtimer * hrtimer)1084 static enum hrtimer_restart isotp_echo_timer_handler(struct hrtimer *hrtimer)
1085 {
1086 struct isotp_sock *so = container_of(hrtimer, struct isotp_sock,
1087 echotimer);
1088
1089 return isotp_tx_timeout(so);
1090 }
1091
isotp_txfr_timer_handler(struct hrtimer * hrtimer)1092 static enum hrtimer_restart isotp_txfr_timer_handler(struct hrtimer *hrtimer)
1093 {
1094 struct isotp_sock *so = container_of(hrtimer, struct isotp_sock,
1095 txfrtimer);
1096
1097 /* start echo timeout handling and cover below protocol error */
1098 hrtimer_start(&so->echotimer, ktime_set(ISOTP_ECHO_TIMEOUT, 0),
1099 HRTIMER_MODE_REL_SOFT);
1100
1101 /* cfecho should be consumed by isotp_rcv_echo() here */
1102 if (READ_ONCE(so->tx.state) == ISOTP_SENDING && !READ_ONCE(so->cfecho))
1103 isotp_send_cframe(so);
1104
1105 return HRTIMER_NORESTART;
1106 }
1107
isotp_sendmsg(struct socket * sock,struct msghdr * msg,size_t size)1108 static int isotp_sendmsg(struct socket *sock, struct msghdr *msg, size_t size)
1109 {
1110 struct sock *sk = sock->sk;
1111 struct isotp_sock *so = isotp_sk(sk);
1112 struct sk_buff *skb;
1113 struct can_skb_ext *csx;
1114 struct net_device *dev;
1115 struct canfd_frame *cf;
1116 int ae = (so->opt.flags & CAN_ISOTP_EXTEND_ADDR) ? 1 : 0;
1117 int wait_tx_done = (so->opt.flags & CAN_ISOTP_WAIT_TX_DONE) ? 1 : 0;
1118 s64 hrtimer_sec = ISOTP_ECHO_TIMEOUT;
1119 struct hrtimer *tx_hrt = &so->echotimer;
1120 u32 new_state = ISOTP_SENDING;
1121 u32 my_gen;
1122 u32 old_cfecho;
1123 int off;
1124 int err;
1125
1126 if (!so->bound || READ_ONCE(so->tx.state) == ISOTP_SHUTDOWN)
1127 return -EADDRNOTAVAIL;
1128
1129 /* claim the socket under so->rx_lock: this serializes the claim
1130 * with the RX path and with sendmsg()'s own error paths below, so
1131 * none of them can ever see a transfer mid-claim
1132 */
1133 for (;;) {
1134 spin_lock_bh(&so->rx_lock);
1135 if (READ_ONCE(so->tx.state) == ISOTP_IDLE)
1136 break;
1137 spin_unlock_bh(&so->rx_lock);
1138
1139 /* we do not support multiple buffers - for now */
1140 if (msg->msg_flags & MSG_DONTWAIT)
1141 return -EAGAIN;
1142
1143 if (READ_ONCE(so->tx.state) == ISOTP_SHUTDOWN)
1144 return -EADDRNOTAVAIL;
1145
1146 /* wait for complete transmission of current pdu */
1147 err = wait_event_interruptible(so->wait,
1148 READ_ONCE(so->tx.state) == ISOTP_IDLE ||
1149 READ_ONCE(so->tx.state) == ISOTP_SHUTDOWN);
1150 if (err)
1151 return err;
1152 }
1153
1154 /* txfrtimer's callback re-arms echotimer lock-free: drain it first */
1155 hrtimer_cancel(&so->txfrtimer);
1156 hrtimer_cancel(&so->txtimer);
1157 hrtimer_cancel(&so->echotimer);
1158
1159 /* new transfer: increment so->tx_gen and set tx.state after barrier */
1160 my_gen = isotp_inc_tx_gen(READ_ONCE(so->tx_gen));
1161 isotp_set_tx_result(so, my_gen, ECOMM); /* prevent stale slot matching */
1162 WRITE_ONCE(so->tx_gen, my_gen);
1163 smp_wmb(); /* see smp_load_acquire() in isotp_tx_[timeout|gen_done] */
1164 WRITE_ONCE(so->tx.state, ISOTP_SENDING);
1165 WRITE_ONCE(so->cfecho, 0);
1166 spin_unlock_bh(&so->rx_lock);
1167
1168 /* so->bound is only checked once above - a wakeup may have
1169 * unbound/rebound the socket meanwhile => recheck
1170 */
1171 if (!so->bound) {
1172 err = -EADDRNOTAVAIL;
1173 goto err_out_drop;
1174 }
1175
1176 /* PDU size > default => try max_pdu_size */
1177 if (size > so->tx.buflen && so->tx.buflen < max_pdu_size) {
1178 u8 *newbuf = kmalloc(max_pdu_size, GFP_KERNEL);
1179
1180 if (newbuf) {
1181 so->tx.buf = newbuf;
1182 so->tx.buflen = max_pdu_size;
1183 }
1184 }
1185
1186 if (!size || size > so->tx.buflen) {
1187 err = -EINVAL;
1188 goto err_out_drop;
1189 }
1190
1191 /* take care of a potential SF_DL ESC offset for TX_DL > 8 */
1192 off = (so->tx.ll_dl > CAN_MAX_DLEN) ? 1 : 0;
1193
1194 /* does the given data fit into a single frame for SF_BROADCAST? */
1195 if ((isotp_bc_flags(so) == CAN_ISOTP_SF_BROADCAST) &&
1196 (size > so->tx.ll_dl - SF_PCI_SZ4 - ae - off)) {
1197 err = -EINVAL;
1198 goto err_out_drop;
1199 }
1200
1201 err = memcpy_from_msg(so->tx.buf, msg, size);
1202 if (err < 0)
1203 goto err_out_drop;
1204
1205 dev = dev_get_by_index(sock_net(sk), so->ifindex);
1206 if (!dev) {
1207 err = -ENXIO;
1208 goto err_out_drop;
1209 }
1210
1211 skb = sock_alloc_send_skb(sk, so->ll.mtu, msg->msg_flags & MSG_DONTWAIT,
1212 &err);
1213 if (!skb) {
1214 dev_put(dev);
1215 goto err_out_drop;
1216 }
1217
1218 csx = can_skb_ext_add(skb);
1219 if (!csx) {
1220 kfree_skb(skb);
1221 netdev_put(dev, NULL);
1222 err = -ENOMEM;
1223 goto err_out_drop;
1224 }
1225
1226 csx->can_iif = dev->ifindex;
1227
1228 /* set uid in tx skb to identify CF echo frames */
1229 can_set_skb_uid(csx);
1230
1231 so->tx.len = size;
1232 so->tx.idx = 0;
1233
1234 cf = (struct canfd_frame *)skb->data;
1235 skb_put_zero(skb, so->ll.mtu);
1236
1237 /* cfecho should have been zero'ed by init / former isotp_rcv_echo() */
1238 old_cfecho = READ_ONCE(so->cfecho);
1239 if (old_cfecho)
1240 pr_notice_once("can-isotp: uninit cfecho %08X\n", old_cfecho);
1241
1242 /* check for single frame transmission depending on TX_DL */
1243 if (size <= so->tx.ll_dl - SF_PCI_SZ4 - ae - off) {
1244 /* The message size generally fits into a SingleFrame - good.
1245 *
1246 * SF_DL ESC offset optimization:
1247 *
1248 * When TX_DL is greater 8 but the message would still fit
1249 * into a 8 byte CAN frame, we can omit the offset.
1250 * This prevents a protocol caused length extension from
1251 * CAN_DL = 8 to CAN_DL = 12 due to the SF_SL ESC handling.
1252 */
1253 if (size <= CAN_MAX_DLEN - SF_PCI_SZ4 - ae)
1254 off = 0;
1255
1256 isotp_fill_dataframe(cf, so, ae, off);
1257
1258 /* place single frame N_PCI w/o length in appropriate index */
1259 cf->data[ae] = N_PCI_SF;
1260
1261 /* place SF_DL size value depending on the SF_DL ESC offset */
1262 if (off)
1263 cf->data[SF_PCI_SZ4 + ae] = size;
1264 else
1265 cf->data[ae] |= size;
1266
1267 /* set CF echo tag for isotp_rcv_echo() (SF-mode) */
1268 WRITE_ONCE(so->cfecho, csx->can_skb_uid);
1269 } else {
1270 /* send first frame */
1271
1272 isotp_create_fframe(cf, so, ae);
1273
1274 if (isotp_bc_flags(so) == CAN_ISOTP_CF_BROADCAST) {
1275 /* set timer for FC-less operation (STmin = 0) */
1276 if (so->opt.flags & CAN_ISOTP_FORCE_TXSTMIN)
1277 so->tx_gap = ktime_set(0, so->force_tx_stmin);
1278 else
1279 so->tx_gap = ktime_set(0, so->frame_txtime);
1280
1281 /* disable wait for FCs due to activated block size */
1282 so->txfc.bs = 0;
1283
1284 /* set CF echo tag for isotp_rcv_echo() (CF-mode) */
1285 WRITE_ONCE(so->cfecho, csx->can_skb_uid);
1286 } else {
1287 /* standard flow control check */
1288 new_state = ISOTP_WAIT_FIRST_FC;
1289
1290 /* start timeout for FC */
1291 hrtimer_sec = ISOTP_FC_TIMEOUT;
1292 tx_hrt = &so->txtimer;
1293
1294 /* no CF echo tag for isotp_rcv_echo() (FF-mode) */
1295 WRITE_ONCE(so->cfecho, 0);
1296 }
1297 }
1298
1299 spin_lock_bh(&so->rx_lock);
1300 if (READ_ONCE(so->tx.state) == ISOTP_SHUTDOWN) {
1301 /* isotp_release() has since taken over and already drained
1302 * our timers - don't send into a socket that's going away
1303 */
1304 spin_unlock_bh(&so->rx_lock);
1305 kfree_skb(skb);
1306 dev_put(dev);
1307 wake_up_interruptible(&so->wait);
1308 return -EADDRNOTAVAIL;
1309 }
1310 /* WAIT_FIRST_FC for standard FF, else stays ISOTP_SENDING */
1311 WRITE_ONCE(so->tx.state, new_state);
1312 hrtimer_start(tx_hrt, ktime_set(hrtimer_sec, 0),
1313 HRTIMER_MODE_REL_SOFT);
1314 spin_unlock_bh(&so->rx_lock);
1315
1316 /* send the first or only CAN frame */
1317 cf->flags = so->ll.tx_flags;
1318
1319 skb->dev = dev;
1320 skb->sk = sk;
1321 err = can_send(skb, 1);
1322 dev_put(dev);
1323 if (err) {
1324 pr_notice_once("can-isotp: %s: can_send_ret %pe\n",
1325 __func__, ERR_PTR(err));
1326
1327 spin_lock_bh(&so->rx_lock);
1328
1329 /* new transfer already claimed by a concurrent completion,
1330 * timeout or sendmsg() while we were stuck in can_send()?
1331 */
1332 if (READ_ONCE(so->tx_gen) != my_gen) {
1333 /* don't touch timers and state of the new transfer */
1334 spin_unlock_bh(&so->rx_lock);
1335 return err;
1336 }
1337
1338 /* no transmission -> no timeout monitoring */
1339 hrtimer_cancel(tx_hrt);
1340 goto err_out_drop_locked;
1341 }
1342
1343 if (wait_tx_done) {
1344 /* wake up for:
1345 * - concurrent sendmsg() claiming a new transfer
1346 * - complete transmission of current PDU
1347 * - shutdown state change in isotp_release()
1348 * isotp_tx_gen_done() uses common tx.state/tx_gen read sequence
1349 */
1350 err = wait_event_interruptible(so->wait,
1351 isotp_tx_gen_done(so, my_gen));
1352 if (err)
1353 goto err_event_drop;
1354
1355 /* still our claim, but isotp_release() force-shut it down */
1356 if (smp_load_acquire(&so->tx.state) == ISOTP_SHUTDOWN &&
1357 READ_ONCE(so->tx_gen) == my_gen) {
1358 err = -EADDRNOTAVAIL;
1359 goto err_event_drop;
1360 }
1361
1362 /* own completion, or tx_gen moved on - either way this is
1363 * what isotp_get_tx_result() recorded for my_gen
1364 */
1365 err = isotp_get_tx_result(so, my_gen);
1366
1367 /* drain to avoid stale error for a later poll()/SO_ERROR */
1368 sock_error(sk);
1369
1370 return err ? err : size;
1371 }
1372
1373 return size;
1374
1375 err_out_drop:
1376 /* claimed but nothing sent yet - no timer to cancel */
1377 spin_lock_bh(&so->rx_lock);
1378 goto err_out_drop_locked;
1379 err_event_drop:
1380 /* interrupted or shut down while waiting on our own transfer */
1381 spin_lock_bh(&so->rx_lock);
1382
1383 /* new transfer already started by concurrent sendmsg()? */
1384 if (READ_ONCE(so->tx_gen) != my_gen) {
1385 /* don't touch timers and states of the new transfer */
1386 spin_unlock_bh(&so->rx_lock);
1387 return err;
1388 }
1389
1390 hrtimer_cancel(&so->txfrtimer);
1391 hrtimer_cancel(&so->txtimer);
1392 hrtimer_cancel(&so->echotimer);
1393 err_out_drop_locked:
1394 /* release the claim; so->rx_lock still held from above */
1395 WRITE_ONCE(so->cfecho, 0);
1396
1397 /* only claim to IDLE if isotp_release() has not taken over */
1398 if (READ_ONCE(so->tx.state) != ISOTP_SHUTDOWN)
1399 WRITE_ONCE(so->tx.state, ISOTP_IDLE);
1400 spin_unlock_bh(&so->rx_lock);
1401 wake_up_interruptible(&so->wait);
1402
1403 return err;
1404 }
1405
isotp_recvmsg(struct socket * sock,struct msghdr * msg,size_t size,int flags)1406 static int isotp_recvmsg(struct socket *sock, struct msghdr *msg, size_t size,
1407 int flags)
1408 {
1409 struct sock *sk = sock->sk;
1410 struct sk_buff *skb;
1411 struct isotp_sock *so = isotp_sk(sk);
1412 int ret = 0;
1413
1414 if (flags & ~(MSG_DONTWAIT | MSG_TRUNC | MSG_PEEK | MSG_CMSG_COMPAT))
1415 return -EINVAL;
1416
1417 if (!so->bound)
1418 return -EADDRNOTAVAIL;
1419
1420 skb = skb_recv_datagram(sk, flags, &ret);
1421 if (!skb)
1422 return ret;
1423
1424 if (size < skb->len)
1425 msg->msg_flags |= MSG_TRUNC;
1426 else
1427 size = skb->len;
1428
1429 ret = memcpy_to_msg(msg, skb->data, size);
1430 if (ret < 0)
1431 goto out_err;
1432
1433 sock_recv_cmsgs(msg, sk, skb);
1434
1435 if (msg->msg_name) {
1436 __sockaddr_check_size(ISOTP_MIN_NAMELEN);
1437 msg->msg_namelen = ISOTP_MIN_NAMELEN;
1438 memcpy(msg->msg_name, skb->cb, msg->msg_namelen);
1439 }
1440
1441 /* set length of return value */
1442 ret = (flags & MSG_TRUNC) ? skb->len : size;
1443
1444 out_err:
1445 skb_free_datagram(sk, skb);
1446
1447 return ret;
1448 }
1449
isotp_release(struct socket * sock)1450 static int isotp_release(struct socket *sock)
1451 {
1452 struct sock *sk = sock->sk;
1453 struct isotp_sock *so;
1454 struct net *net;
1455
1456 if (!sk)
1457 return 0;
1458
1459 so = isotp_sk(sk);
1460 net = sock_net(sk);
1461
1462 /* best-effort: wait for a running pdu to finish, but don't block on
1463 * it forever - give up after the first signal
1464 */
1465 while (READ_ONCE(so->tx.state) != ISOTP_IDLE &&
1466 wait_event_interruptible(so->wait,
1467 READ_ONCE(so->tx.state) == ISOTP_IDLE) == 0)
1468 ;
1469
1470 /* claim the socket under so->rx_lock like sendmsg() does, so its
1471 * claim can't race the forced ISOTP_SHUTDOWN below; force it
1472 * unconditionally, even when a signal cut the wait above short
1473 */
1474 spin_lock_bh(&so->rx_lock);
1475 WRITE_ONCE(so->tx.state, ISOTP_SHUTDOWN);
1476 spin_unlock_bh(&so->rx_lock);
1477 WRITE_ONCE(so->rx.state, ISOTP_IDLE);
1478
1479 /* forced SHUTDOWN may have skipped IDLE (gave up on a signal) */
1480 wake_up_interruptible(&so->wait);
1481
1482 spin_lock(&isotp_notifier_lock);
1483 while (isotp_busy_notifier == so) {
1484 spin_unlock(&isotp_notifier_lock);
1485 schedule_timeout_uninterruptible(1);
1486 spin_lock(&isotp_notifier_lock);
1487 }
1488 list_del(&so->notifier);
1489 spin_unlock(&isotp_notifier_lock);
1490
1491 rtnl_lock();
1492 lock_sock(sk);
1493
1494 /* remove current filters & unregister
1495 * tracked reference so->dev is taken at bind() time with rtnl_lock
1496 */
1497 if (so->bound && so->dev) {
1498 if (isotp_register_rxid(so))
1499 can_rx_unregister(net, so->dev, so->rxid,
1500 SINGLE_MASK(so->rxid),
1501 isotp_rcv, sk);
1502
1503 can_rx_unregister(net, so->dev, so->txid,
1504 SINGLE_MASK(so->txid),
1505 isotp_rcv_echo, sk);
1506 netdev_put(so->dev, &so->dev_tracker);
1507 }
1508
1509 so->ifindex = 0;
1510 so->bound = 0;
1511 so->dev = NULL;
1512
1513 rtnl_unlock();
1514
1515 /* Always wait for a grace period before touching the timers below.
1516 * A concurrent NETDEV_UNREGISTER may have already unregistered our
1517 * filters and cleared so->bound in isotp_notify() without waiting
1518 * for in-flight isotp_rcv() callers to finish, so this call must not
1519 * be skipped just because so->bound is already 0 here.
1520 */
1521 synchronize_rcu();
1522
1523 hrtimer_cancel(&so->txfrtimer);
1524 hrtimer_cancel(&so->txtimer);
1525 hrtimer_cancel(&so->echotimer);
1526 hrtimer_cancel(&so->rxtimer);
1527
1528 sock_orphan(sk);
1529 sock->sk = NULL;
1530
1531 release_sock(sk);
1532 sock_prot_inuse_add(net, sk->sk_prot, -1);
1533 sock_put(sk);
1534
1535 return 0;
1536 }
1537
isotp_bind(struct socket * sock,struct sockaddr_unsized * uaddr,int len)1538 static int isotp_bind(struct socket *sock, struct sockaddr_unsized *uaddr, int len)
1539 {
1540 struct sockaddr_can *addr = (struct sockaddr_can *)uaddr;
1541 struct sock *sk = sock->sk;
1542 struct isotp_sock *so = isotp_sk(sk);
1543 struct net *net = sock_net(sk);
1544 int ifindex;
1545 struct net_device *dev;
1546 canid_t tx_id = addr->can_addr.tp.tx_id;
1547 canid_t rx_id = addr->can_addr.tp.rx_id;
1548 int err = 0;
1549 int notify_enetdown = 0;
1550
1551 if (len < ISOTP_MIN_NAMELEN)
1552 return -EINVAL;
1553
1554 if (addr->can_family != AF_CAN)
1555 return -EINVAL;
1556
1557 /* sanitize tx CAN identifier */
1558 if (tx_id & CAN_EFF_FLAG)
1559 tx_id &= (CAN_EFF_FLAG | CAN_EFF_MASK);
1560 else
1561 tx_id &= CAN_SFF_MASK;
1562
1563 /* give feedback on wrong CAN-ID value */
1564 if (tx_id != addr->can_addr.tp.tx_id)
1565 return -EINVAL;
1566
1567 /* sanitize rx CAN identifier (if needed) */
1568 if (isotp_register_rxid(so)) {
1569 if (rx_id & CAN_EFF_FLAG)
1570 rx_id &= (CAN_EFF_FLAG | CAN_EFF_MASK);
1571 else
1572 rx_id &= CAN_SFF_MASK;
1573
1574 /* give feedback on wrong CAN-ID value */
1575 if (rx_id != addr->can_addr.tp.rx_id)
1576 return -EINVAL;
1577 }
1578
1579 if (!addr->can_ifindex)
1580 return -ENODEV;
1581
1582 rtnl_lock();
1583 lock_sock(sk);
1584
1585 if (so->bound) {
1586 err = -EINVAL;
1587 goto out;
1588 }
1589
1590 /* A transmission or reception that outlived a previous binding
1591 * (unbound by NETDEV_UNREGISTER) may still be draining; the FC/echo
1592 * and RX watchdog timers bound how long this takes. Checked together
1593 * with so->bound in the same lock_sock() section above, so there is
1594 * no window in which a concurrent isotp_notify() could be missed.
1595 */
1596 if (READ_ONCE(so->tx.state) != ISOTP_IDLE ||
1597 READ_ONCE(so->rx.state) != ISOTP_IDLE) {
1598 err = -EAGAIN;
1599 goto out;
1600 }
1601
1602 /* ensure different CAN IDs when the rx_id is to be registered */
1603 if (isotp_register_rxid(so) && rx_id == tx_id) {
1604 err = -EADDRNOTAVAIL;
1605 goto out;
1606 }
1607
1608 dev = dev_get_by_index(net, addr->can_ifindex);
1609 if (!dev) {
1610 err = -ENODEV;
1611 goto out;
1612 }
1613 if (dev->type != ARPHRD_CAN) {
1614 err = -ENODEV;
1615 goto out_put_dev;
1616 }
1617 if (READ_ONCE(dev->mtu) < so->ll.mtu) {
1618 err = -EINVAL;
1619 goto out_put_dev;
1620 }
1621 if (!(dev->flags & IFF_UP))
1622 notify_enetdown = 1;
1623
1624 ifindex = dev->ifindex;
1625
1626 if (isotp_register_rxid(so))
1627 can_rx_register(net, dev, rx_id, SINGLE_MASK(rx_id),
1628 isotp_rcv, sk, "isotp", sk);
1629
1630 /* no consecutive frame echo skb in flight */
1631 WRITE_ONCE(so->cfecho, 0);
1632
1633 /* register for echo skb's */
1634 can_rx_register(net, dev, tx_id, SINGLE_MASK(tx_id),
1635 isotp_rcv_echo, sk, "isotpe", sk);
1636
1637 /* switch to new settings */
1638 so->ifindex = ifindex;
1639 so->rxid = rx_id;
1640 so->txid = tx_id;
1641 so->bound = 1;
1642
1643 /* bind() ok -> hold a reference for so->dev so that isotp_release()
1644 * can safely reach the device later, even if a concurrent
1645 * NETDEV_UNREGISTER has already unlisted it by ifindex.
1646 */
1647 so->dev = dev;
1648 netdev_hold(so->dev, &so->dev_tracker, GFP_KERNEL);
1649
1650 out_put_dev:
1651 /* remove potential reference from dev_get_by_index() */
1652 dev_put(dev);
1653 out:
1654 release_sock(sk);
1655 rtnl_unlock();
1656
1657 if (notify_enetdown) {
1658 sk->sk_err = ENETDOWN;
1659 if (!sock_flag(sk, SOCK_DEAD))
1660 sk_error_report(sk);
1661 }
1662
1663 return err;
1664 }
1665
isotp_getname(struct socket * sock,struct sockaddr * uaddr,int peer)1666 static int isotp_getname(struct socket *sock, struct sockaddr *uaddr, int peer)
1667 {
1668 struct sockaddr_can *addr = (struct sockaddr_can *)uaddr;
1669 struct sock *sk = sock->sk;
1670 struct isotp_sock *so = isotp_sk(sk);
1671
1672 if (peer)
1673 return -EOPNOTSUPP;
1674
1675 memset(addr, 0, ISOTP_MIN_NAMELEN);
1676 addr->can_family = AF_CAN;
1677 addr->can_ifindex = so->ifindex;
1678 addr->can_addr.tp.rx_id = so->rxid;
1679 addr->can_addr.tp.tx_id = so->txid;
1680
1681 return ISOTP_MIN_NAMELEN;
1682 }
1683
isotp_setsockopt_locked(struct socket * sock,int level,int optname,sockptr_t optval,unsigned int optlen)1684 static int isotp_setsockopt_locked(struct socket *sock, int level, int optname,
1685 sockptr_t optval, unsigned int optlen)
1686 {
1687 struct sock *sk = sock->sk;
1688 struct isotp_sock *so = isotp_sk(sk);
1689 int ret = 0;
1690
1691 if (so->bound)
1692 return -EISCONN;
1693
1694 switch (optname) {
1695 case CAN_ISOTP_OPTS:
1696 if (optlen != sizeof(struct can_isotp_options))
1697 return -EINVAL;
1698
1699 if (copy_from_sockptr(&so->opt, optval, optlen))
1700 return -EFAULT;
1701
1702 /* no separate rx_ext_address is given => use ext_address */
1703 if (!(so->opt.flags & CAN_ISOTP_RX_EXT_ADDR))
1704 so->opt.rx_ext_address = so->opt.ext_address;
1705
1706 /* these broadcast flags are not allowed together */
1707 if (isotp_bc_flags(so) == ISOTP_ALL_BC_FLAGS) {
1708 /* CAN_ISOTP_SF_BROADCAST is prioritized */
1709 so->opt.flags &= ~CAN_ISOTP_CF_BROADCAST;
1710
1711 /* give user feedback on wrong config attempt */
1712 ret = -EINVAL;
1713 }
1714
1715 /* check for frame_txtime changes (0 => no changes) */
1716 if (so->opt.frame_txtime) {
1717 if (so->opt.frame_txtime == CAN_ISOTP_FRAME_TXTIME_ZERO)
1718 so->frame_txtime = 0;
1719 else
1720 so->frame_txtime = so->opt.frame_txtime;
1721 }
1722 break;
1723
1724 case CAN_ISOTP_RECV_FC:
1725 if (optlen != sizeof(struct can_isotp_fc_options))
1726 return -EINVAL;
1727
1728 if (copy_from_sockptr(&so->rxfc, optval, optlen))
1729 return -EFAULT;
1730 break;
1731
1732 case CAN_ISOTP_TX_STMIN:
1733 if (optlen != sizeof(u32))
1734 return -EINVAL;
1735
1736 if (copy_from_sockptr(&so->force_tx_stmin, optval, optlen))
1737 return -EFAULT;
1738 break;
1739
1740 case CAN_ISOTP_RX_STMIN:
1741 if (optlen != sizeof(u32))
1742 return -EINVAL;
1743
1744 if (copy_from_sockptr(&so->force_rx_stmin, optval, optlen))
1745 return -EFAULT;
1746 break;
1747
1748 case CAN_ISOTP_LL_OPTS:
1749 if (optlen == sizeof(struct can_isotp_ll_options)) {
1750 struct can_isotp_ll_options ll;
1751
1752 if (copy_from_sockptr(&ll, optval, optlen))
1753 return -EFAULT;
1754
1755 /* check for correct ISO 11898-1 DLC data length */
1756 if (ll.tx_dl != padlen(ll.tx_dl))
1757 return -EINVAL;
1758
1759 if (ll.mtu != CAN_MTU && ll.mtu != CANFD_MTU)
1760 return -EINVAL;
1761
1762 if (ll.mtu == CAN_MTU &&
1763 (ll.tx_dl > CAN_MAX_DLEN || ll.tx_flags != 0))
1764 return -EINVAL;
1765
1766 memcpy(&so->ll, &ll, sizeof(ll));
1767
1768 /* set ll_dl for tx path to similar place as for rx */
1769 so->tx.ll_dl = ll.tx_dl;
1770 } else {
1771 return -EINVAL;
1772 }
1773 break;
1774
1775 default:
1776 ret = -ENOPROTOOPT;
1777 }
1778
1779 return ret;
1780 }
1781
isotp_setsockopt(struct socket * sock,int level,int optname,sockptr_t optval,unsigned int optlen)1782 static int isotp_setsockopt(struct socket *sock, int level, int optname,
1783 sockptr_t optval, unsigned int optlen)
1784
1785 {
1786 struct sock *sk = sock->sk;
1787 int ret;
1788
1789 if (level != SOL_CAN_ISOTP)
1790 return -EINVAL;
1791
1792 lock_sock(sk);
1793 ret = isotp_setsockopt_locked(sock, level, optname, optval, optlen);
1794 release_sock(sk);
1795 return ret;
1796 }
1797
isotp_getsockopt(struct socket * sock,int level,int optname,char __user * optval,int __user * optlen)1798 static int isotp_getsockopt(struct socket *sock, int level, int optname,
1799 char __user *optval, int __user *optlen)
1800 {
1801 struct sock *sk = sock->sk;
1802 struct isotp_sock *so = isotp_sk(sk);
1803 int len;
1804 void *val;
1805
1806 if (level != SOL_CAN_ISOTP)
1807 return -EINVAL;
1808 if (get_user(len, optlen))
1809 return -EFAULT;
1810 if (len < 0)
1811 return -EINVAL;
1812
1813 switch (optname) {
1814 case CAN_ISOTP_OPTS:
1815 len = min_t(int, len, sizeof(struct can_isotp_options));
1816 val = &so->opt;
1817 break;
1818
1819 case CAN_ISOTP_RECV_FC:
1820 len = min_t(int, len, sizeof(struct can_isotp_fc_options));
1821 val = &so->rxfc;
1822 break;
1823
1824 case CAN_ISOTP_TX_STMIN:
1825 len = min_t(int, len, sizeof(u32));
1826 val = &so->force_tx_stmin;
1827 break;
1828
1829 case CAN_ISOTP_RX_STMIN:
1830 len = min_t(int, len, sizeof(u32));
1831 val = &so->force_rx_stmin;
1832 break;
1833
1834 case CAN_ISOTP_LL_OPTS:
1835 len = min_t(int, len, sizeof(struct can_isotp_ll_options));
1836 val = &so->ll;
1837 break;
1838
1839 default:
1840 return -ENOPROTOOPT;
1841 }
1842
1843 if (put_user(len, optlen))
1844 return -EFAULT;
1845 if (copy_to_user(optval, val, len))
1846 return -EFAULT;
1847 return 0;
1848 }
1849
isotp_notify(struct isotp_sock * so,unsigned long msg,struct net_device * dev)1850 static void isotp_notify(struct isotp_sock *so, unsigned long msg,
1851 struct net_device *dev)
1852 {
1853 struct sock *sk = &so->sk;
1854
1855 if (!net_eq(dev_net(dev), sock_net(sk)))
1856 return;
1857
1858 if (so->dev != dev)
1859 return;
1860
1861 switch (msg) {
1862 case NETDEV_UNREGISTER:
1863 lock_sock(sk);
1864 /* remove current filters & unregister */
1865 if (so->bound) {
1866 if (isotp_register_rxid(so))
1867 can_rx_unregister(dev_net(dev), dev, so->rxid,
1868 SINGLE_MASK(so->rxid),
1869 isotp_rcv, sk);
1870
1871 can_rx_unregister(dev_net(dev), dev, so->txid,
1872 SINGLE_MASK(so->txid),
1873 isotp_rcv_echo, sk);
1874 netdev_put(so->dev, &so->dev_tracker);
1875 }
1876
1877 so->ifindex = 0;
1878 so->bound = 0;
1879 so->dev = NULL;
1880 release_sock(sk);
1881
1882 sk->sk_err = ENODEV;
1883 if (!sock_flag(sk, SOCK_DEAD))
1884 sk_error_report(sk);
1885 break;
1886
1887 case NETDEV_DOWN:
1888 sk->sk_err = ENETDOWN;
1889 if (!sock_flag(sk, SOCK_DEAD))
1890 sk_error_report(sk);
1891 break;
1892 }
1893 }
1894
isotp_notifier(struct notifier_block * nb,unsigned long msg,void * ptr)1895 static int isotp_notifier(struct notifier_block *nb, unsigned long msg,
1896 void *ptr)
1897 {
1898 struct net_device *dev = netdev_notifier_info_to_dev(ptr);
1899
1900 if (dev->type != ARPHRD_CAN)
1901 return NOTIFY_DONE;
1902 if (msg != NETDEV_UNREGISTER && msg != NETDEV_DOWN)
1903 return NOTIFY_DONE;
1904 if (unlikely(isotp_busy_notifier)) /* Check for reentrant bug. */
1905 return NOTIFY_DONE;
1906
1907 spin_lock(&isotp_notifier_lock);
1908 list_for_each_entry(isotp_busy_notifier, &isotp_notifier_list, notifier) {
1909 spin_unlock(&isotp_notifier_lock);
1910 isotp_notify(isotp_busy_notifier, msg, dev);
1911 spin_lock(&isotp_notifier_lock);
1912 }
1913 isotp_busy_notifier = NULL;
1914 spin_unlock(&isotp_notifier_lock);
1915 return NOTIFY_DONE;
1916 }
1917
isotp_sock_destruct(struct sock * sk)1918 static void isotp_sock_destruct(struct sock *sk)
1919 {
1920 struct isotp_sock *so = isotp_sk(sk);
1921
1922 /* do the standard CAN sock destruct work */
1923 can_sock_destruct(sk);
1924
1925 /* free potential extended PDU buffers */
1926 if (so->rx.buf != so->rx.sbuf)
1927 kfree(so->rx.buf);
1928
1929 if (so->tx.buf != so->tx.sbuf)
1930 kfree(so->tx.buf);
1931 }
1932
isotp_init(struct sock * sk)1933 static int isotp_init(struct sock *sk)
1934 {
1935 struct isotp_sock *so = isotp_sk(sk);
1936
1937 so->ifindex = 0;
1938 so->bound = 0;
1939 so->dev = NULL;
1940
1941 so->opt.flags = CAN_ISOTP_DEFAULT_FLAGS;
1942 so->opt.ext_address = CAN_ISOTP_DEFAULT_EXT_ADDRESS;
1943 so->opt.rx_ext_address = CAN_ISOTP_DEFAULT_EXT_ADDRESS;
1944 so->opt.rxpad_content = CAN_ISOTP_DEFAULT_PAD_CONTENT;
1945 so->opt.txpad_content = CAN_ISOTP_DEFAULT_PAD_CONTENT;
1946 so->opt.frame_txtime = CAN_ISOTP_DEFAULT_FRAME_TXTIME;
1947 so->frame_txtime = CAN_ISOTP_DEFAULT_FRAME_TXTIME;
1948 so->rxfc.bs = CAN_ISOTP_DEFAULT_RECV_BS;
1949 so->rxfc.stmin = CAN_ISOTP_DEFAULT_RECV_STMIN;
1950 so->rxfc.wftmax = CAN_ISOTP_DEFAULT_RECV_WFTMAX;
1951 so->ll.mtu = CAN_ISOTP_DEFAULT_LL_MTU;
1952 so->ll.tx_dl = CAN_ISOTP_DEFAULT_LL_TX_DL;
1953 so->ll.tx_flags = CAN_ISOTP_DEFAULT_LL_TX_FLAGS;
1954
1955 /* set ll_dl for tx path to similar place as for rx */
1956 so->tx.ll_dl = so->ll.tx_dl;
1957
1958 so->rx.state = ISOTP_IDLE;
1959 so->tx.state = ISOTP_IDLE;
1960
1961 so->rx.buf = so->rx.sbuf;
1962 so->tx.buf = so->tx.sbuf;
1963 so->rx.buflen = ARRAY_SIZE(so->rx.sbuf);
1964 so->tx.buflen = ARRAY_SIZE(so->tx.sbuf);
1965
1966 hrtimer_setup(&so->rxtimer, isotp_rx_timer_handler,
1967 CLOCK_MONOTONIC, HRTIMER_MODE_REL_SOFT);
1968 hrtimer_setup(&so->txtimer, isotp_tx_timer_handler,
1969 CLOCK_MONOTONIC, HRTIMER_MODE_REL_SOFT);
1970 hrtimer_setup(&so->echotimer, isotp_echo_timer_handler,
1971 CLOCK_MONOTONIC, HRTIMER_MODE_REL_SOFT);
1972 hrtimer_setup(&so->txfrtimer, isotp_txfr_timer_handler,
1973 CLOCK_MONOTONIC, HRTIMER_MODE_REL_SOFT);
1974
1975 init_waitqueue_head(&so->wait);
1976 spin_lock_init(&so->rx_lock);
1977
1978 spin_lock(&isotp_notifier_lock);
1979 list_add_tail(&so->notifier, &isotp_notifier_list);
1980 spin_unlock(&isotp_notifier_lock);
1981
1982 /* re-assign default can_sock_destruct() reference */
1983 sk->sk_destruct = isotp_sock_destruct;
1984
1985 return 0;
1986 }
1987
isotp_poll(struct file * file,struct socket * sock,poll_table * wait)1988 static __poll_t isotp_poll(struct file *file, struct socket *sock, poll_table *wait)
1989 {
1990 struct sock *sk = sock->sk;
1991 struct isotp_sock *so = isotp_sk(sk);
1992
1993 __poll_t mask = datagram_poll(file, sock, wait);
1994 poll_wait(file, &so->wait, wait);
1995
1996 /* Check for false positives due to TX state */
1997 if ((mask & EPOLLWRNORM) && (READ_ONCE(so->tx.state) != ISOTP_IDLE))
1998 mask &= ~(EPOLLOUT | EPOLLWRNORM);
1999
2000 return mask;
2001 }
2002
isotp_sock_no_ioctlcmd(struct socket * sock,unsigned int cmd,unsigned long arg)2003 static int isotp_sock_no_ioctlcmd(struct socket *sock, unsigned int cmd,
2004 unsigned long arg)
2005 {
2006 /* no ioctls for socket layer -> hand it down to NIC layer */
2007 return -ENOIOCTLCMD;
2008 }
2009
2010 static const struct proto_ops isotp_ops = {
2011 .family = PF_CAN,
2012 .release = isotp_release,
2013 .bind = isotp_bind,
2014 .connect = sock_no_connect,
2015 .socketpair = sock_no_socketpair,
2016 .accept = sock_no_accept,
2017 .getname = isotp_getname,
2018 .poll = isotp_poll,
2019 .ioctl = isotp_sock_no_ioctlcmd,
2020 .gettstamp = sock_gettstamp,
2021 .listen = sock_no_listen,
2022 .shutdown = sock_no_shutdown,
2023 .setsockopt = isotp_setsockopt,
2024 .getsockopt = isotp_getsockopt,
2025 .sendmsg = isotp_sendmsg,
2026 .recvmsg = isotp_recvmsg,
2027 .mmap = sock_no_mmap,
2028 };
2029
2030 static struct proto isotp_proto __read_mostly = {
2031 .name = "CAN_ISOTP",
2032 .owner = THIS_MODULE,
2033 .obj_size = sizeof(struct isotp_sock),
2034 .init = isotp_init,
2035 };
2036
2037 static const struct can_proto isotp_can_proto = {
2038 .type = SOCK_DGRAM,
2039 .protocol = CAN_ISOTP,
2040 .ops = &isotp_ops,
2041 .prot = &isotp_proto,
2042 };
2043
2044 static struct notifier_block canisotp_notifier = {
2045 .notifier_call = isotp_notifier
2046 };
2047
isotp_module_init(void)2048 static __init int isotp_module_init(void)
2049 {
2050 int err;
2051
2052 max_pdu_size = max_t(unsigned int, max_pdu_size, MAX_12BIT_PDU_SIZE);
2053 max_pdu_size = min_t(unsigned int, max_pdu_size, MAX_PDU_SIZE);
2054
2055 pr_info("can: isotp protocol (max_pdu_size %d)\n", max_pdu_size);
2056
2057 err = register_netdevice_notifier(&canisotp_notifier);
2058 if (err)
2059 return err;
2060
2061 err = can_proto_register(&isotp_can_proto);
2062 if (err < 0) {
2063 pr_err("can: registration of isotp protocol failed %pe\n", ERR_PTR(err));
2064 unregister_netdevice_notifier(&canisotp_notifier);
2065 return err;
2066 }
2067
2068 return 0;
2069 }
2070
isotp_module_exit(void)2071 static __exit void isotp_module_exit(void)
2072 {
2073 can_proto_unregister(&isotp_can_proto);
2074 unregister_netdevice_notifier(&canisotp_notifier);
2075 }
2076
2077 module_init(isotp_module_init);
2078 module_exit(isotp_module_exit);
2079