xref: /linux/net/can/isotp.c (revision 0c8a32eed1625a65798286fb73fea8710a908545)
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  * - take care of the tx-queue-len as traffic shaping is still on the TODO list
18  *
19  * Copyright (c) 2020 Volkswagen Group Electronic Research
20  * All rights reserved.
21  *
22  * Redistribution and use in source and binary forms, with or without
23  * modification, are permitted provided that the following conditions
24  * are met:
25  * 1. Redistributions of source code must retain the above copyright
26  *    notice, this list of conditions and the following disclaimer.
27  * 2. Redistributions in binary form must reproduce the above copyright
28  *    notice, this list of conditions and the following disclaimer in the
29  *    documentation and/or other materials provided with the distribution.
30  * 3. Neither the name of Volkswagen nor the names of its contributors
31  *    may be used to endorse or promote products derived from this software
32  *    without specific prior written permission.
33  *
34  * Alternatively, provided that this notice is retained in full, this
35  * software may be distributed under the terms of the GNU General
36  * Public License ("GPL") version 2, in which case the provisions of the
37  * GPL apply INSTEAD OF those given above.
38  *
39  * The provided data structures and external interfaces from this code
40  * are not restricted to be used by modules with a GPL compatible license.
41  *
42  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
43  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
44  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
45  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
46  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
47  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
48  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
49  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
50  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
51  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
52  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
53  * DAMAGE.
54  */
55 
56 #include <linux/module.h>
57 #include <linux/init.h>
58 #include <linux/interrupt.h>
59 #include <linux/hrtimer.h>
60 #include <linux/wait.h>
61 #include <linux/uio.h>
62 #include <linux/net.h>
63 #include <linux/netdevice.h>
64 #include <linux/socket.h>
65 #include <linux/if_arp.h>
66 #include <linux/skbuff.h>
67 #include <linux/can.h>
68 #include <linux/can/core.h>
69 #include <linux/can/skb.h>
70 #include <linux/can/isotp.h>
71 #include <linux/slab.h>
72 #include <net/sock.h>
73 #include <net/net_namespace.h>
74 
75 MODULE_DESCRIPTION("PF_CAN isotp 15765-2:2016 protocol");
76 MODULE_LICENSE("Dual BSD/GPL");
77 MODULE_AUTHOR("Oliver Hartkopp <socketcan@hartkopp.net>");
78 MODULE_ALIAS("can-proto-6");
79 
80 #define SINGLE_MASK(id) (((id) & CAN_EFF_FLAG) ? \
81 			 (CAN_EFF_MASK | CAN_EFF_FLAG | CAN_RTR_FLAG) : \
82 			 (CAN_SFF_MASK | CAN_EFF_FLAG | CAN_RTR_FLAG))
83 
84 /* ISO 15765-2:2016 supports more than 4095 byte per ISO PDU as the FF_DL can
85  * take full 32 bit values (4 Gbyte). We would need some good concept to handle
86  * this between user space and kernel space. For now increase the static buffer
87  * to something about 8 kbyte to be able to test this new functionality.
88  */
89 #define MAX_MSG_LENGTH 8200
90 
91 /* N_PCI type values in bits 7-4 of N_PCI bytes */
92 #define N_PCI_SF 0x00	/* single frame */
93 #define N_PCI_FF 0x10	/* first frame */
94 #define N_PCI_CF 0x20	/* consecutive frame */
95 #define N_PCI_FC 0x30	/* flow control */
96 
97 #define N_PCI_SZ 1	/* size of the PCI byte #1 */
98 #define SF_PCI_SZ4 1	/* size of SingleFrame PCI including 4 bit SF_DL */
99 #define SF_PCI_SZ8 2	/* size of SingleFrame PCI including 8 bit SF_DL */
100 #define FF_PCI_SZ12 2	/* size of FirstFrame PCI including 12 bit FF_DL */
101 #define FF_PCI_SZ32 6	/* size of FirstFrame PCI including 32 bit FF_DL */
102 #define FC_CONTENT_SZ 3	/* flow control content size in byte (FS/BS/STmin) */
103 
104 #define ISOTP_CHECK_PADDING (CAN_ISOTP_CHK_PAD_LEN | CAN_ISOTP_CHK_PAD_DATA)
105 
106 /* Flow Status given in FC frame */
107 #define ISOTP_FC_CTS 0		/* clear to send */
108 #define ISOTP_FC_WT 1		/* wait */
109 #define ISOTP_FC_OVFLW 2	/* overflow */
110 
111 enum {
112 	ISOTP_IDLE = 0,
113 	ISOTP_WAIT_FIRST_FC,
114 	ISOTP_WAIT_FC,
115 	ISOTP_WAIT_DATA,
116 	ISOTP_SENDING
117 };
118 
119 struct tpcon {
120 	int idx;
121 	int len;
122 	u8 state;
123 	u8 bs;
124 	u8 sn;
125 	u8 ll_dl;
126 	u8 buf[MAX_MSG_LENGTH + 1];
127 };
128 
129 struct isotp_sock {
130 	struct sock sk;
131 	int bound;
132 	int ifindex;
133 	canid_t txid;
134 	canid_t rxid;
135 	ktime_t tx_gap;
136 	ktime_t lastrxcf_tstamp;
137 	struct hrtimer rxtimer, txtimer;
138 	struct can_isotp_options opt;
139 	struct can_isotp_fc_options rxfc, txfc;
140 	struct can_isotp_ll_options ll;
141 	u32 force_tx_stmin;
142 	u32 force_rx_stmin;
143 	struct tpcon rx, tx;
144 	struct notifier_block notifier;
145 	wait_queue_head_t wait;
146 };
147 
148 static inline struct isotp_sock *isotp_sk(const struct sock *sk)
149 {
150 	return (struct isotp_sock *)sk;
151 }
152 
153 static enum hrtimer_restart isotp_rx_timer_handler(struct hrtimer *hrtimer)
154 {
155 	struct isotp_sock *so = container_of(hrtimer, struct isotp_sock,
156 					     rxtimer);
157 	struct sock *sk = &so->sk;
158 
159 	if (so->rx.state == ISOTP_WAIT_DATA) {
160 		/* we did not get new data frames in time */
161 
162 		/* report 'connection timed out' */
163 		sk->sk_err = ETIMEDOUT;
164 		if (!sock_flag(sk, SOCK_DEAD))
165 			sk->sk_error_report(sk);
166 
167 		/* reset rx state */
168 		so->rx.state = ISOTP_IDLE;
169 	}
170 
171 	return HRTIMER_NORESTART;
172 }
173 
174 static int isotp_send_fc(struct sock *sk, int ae, u8 flowstatus)
175 {
176 	struct net_device *dev;
177 	struct sk_buff *nskb;
178 	struct canfd_frame *ncf;
179 	struct isotp_sock *so = isotp_sk(sk);
180 	int can_send_ret;
181 
182 	nskb = alloc_skb(so->ll.mtu + sizeof(struct can_skb_priv), gfp_any());
183 	if (!nskb)
184 		return 1;
185 
186 	dev = dev_get_by_index(sock_net(sk), so->ifindex);
187 	if (!dev) {
188 		kfree_skb(nskb);
189 		return 1;
190 	}
191 
192 	can_skb_reserve(nskb);
193 	can_skb_prv(nskb)->ifindex = dev->ifindex;
194 	can_skb_prv(nskb)->skbcnt = 0;
195 
196 	nskb->dev = dev;
197 	can_skb_set_owner(nskb, sk);
198 	ncf = (struct canfd_frame *)nskb->data;
199 	skb_put(nskb, so->ll.mtu);
200 
201 	/* create & send flow control reply */
202 	ncf->can_id = so->txid;
203 
204 	if (so->opt.flags & CAN_ISOTP_TX_PADDING) {
205 		memset(ncf->data, so->opt.txpad_content, CAN_MAX_DLEN);
206 		ncf->len = CAN_MAX_DLEN;
207 	} else {
208 		ncf->len = ae + FC_CONTENT_SZ;
209 	}
210 
211 	ncf->data[ae] = N_PCI_FC | flowstatus;
212 	ncf->data[ae + 1] = so->rxfc.bs;
213 	ncf->data[ae + 2] = so->rxfc.stmin;
214 
215 	if (ae)
216 		ncf->data[0] = so->opt.ext_address;
217 
218 	if (so->ll.mtu == CANFD_MTU)
219 		ncf->flags = so->ll.tx_flags;
220 
221 	can_send_ret = can_send(nskb, 1);
222 	if (can_send_ret)
223 		pr_notice_once("can-isotp: %s: can_send_ret %d\n",
224 			       __func__, can_send_ret);
225 
226 	dev_put(dev);
227 
228 	/* reset blocksize counter */
229 	so->rx.bs = 0;
230 
231 	/* reset last CF frame rx timestamp for rx stmin enforcement */
232 	so->lastrxcf_tstamp = ktime_set(0, 0);
233 
234 	/* start rx timeout watchdog */
235 	hrtimer_start(&so->rxtimer, ktime_set(1, 0), HRTIMER_MODE_REL_SOFT);
236 	return 0;
237 }
238 
239 static void isotp_rcv_skb(struct sk_buff *skb, struct sock *sk)
240 {
241 	struct sockaddr_can *addr = (struct sockaddr_can *)skb->cb;
242 
243 	BUILD_BUG_ON(sizeof(skb->cb) < sizeof(struct sockaddr_can));
244 
245 	memset(addr, 0, sizeof(*addr));
246 	addr->can_family = AF_CAN;
247 	addr->can_ifindex = skb->dev->ifindex;
248 
249 	if (sock_queue_rcv_skb(sk, skb) < 0)
250 		kfree_skb(skb);
251 }
252 
253 static u8 padlen(u8 datalen)
254 {
255 	static const u8 plen[] = {
256 		8, 8, 8, 8, 8, 8, 8, 8, 8,	/* 0 - 8 */
257 		12, 12, 12, 12,			/* 9 - 12 */
258 		16, 16, 16, 16,			/* 13 - 16 */
259 		20, 20, 20, 20,			/* 17 - 20 */
260 		24, 24, 24, 24,			/* 21 - 24 */
261 		32, 32, 32, 32, 32, 32, 32, 32,	/* 25 - 32 */
262 		48, 48, 48, 48, 48, 48, 48, 48,	/* 33 - 40 */
263 		48, 48, 48, 48, 48, 48, 48, 48	/* 41 - 48 */
264 	};
265 
266 	if (datalen > 48)
267 		return 64;
268 
269 	return plen[datalen];
270 }
271 
272 /* check for length optimization and return 1/true when the check fails */
273 static int check_optimized(struct canfd_frame *cf, int start_index)
274 {
275 	/* for CAN_DL <= 8 the start_index is equal to the CAN_DL as the
276 	 * padding would start at this point. E.g. if the padding would
277 	 * start at cf.data[7] cf->len has to be 7 to be optimal.
278 	 * Note: The data[] index starts with zero.
279 	 */
280 	if (cf->len <= CAN_MAX_DLEN)
281 		return (cf->len != start_index);
282 
283 	/* This relation is also valid in the non-linear DLC range, where
284 	 * we need to take care of the minimal next possible CAN_DL.
285 	 * The correct check would be (padlen(cf->len) != padlen(start_index)).
286 	 * But as cf->len can only take discrete values from 12, .., 64 at this
287 	 * point the padlen(cf->len) is always equal to cf->len.
288 	 */
289 	return (cf->len != padlen(start_index));
290 }
291 
292 /* check padding and return 1/true when the check fails */
293 static int check_pad(struct isotp_sock *so, struct canfd_frame *cf,
294 		     int start_index, u8 content)
295 {
296 	int i;
297 
298 	/* no RX_PADDING value => check length of optimized frame length */
299 	if (!(so->opt.flags & CAN_ISOTP_RX_PADDING)) {
300 		if (so->opt.flags & CAN_ISOTP_CHK_PAD_LEN)
301 			return check_optimized(cf, start_index);
302 
303 		/* no valid test against empty value => ignore frame */
304 		return 1;
305 	}
306 
307 	/* check datalength of correctly padded CAN frame */
308 	if ((so->opt.flags & CAN_ISOTP_CHK_PAD_LEN) &&
309 	    cf->len != padlen(cf->len))
310 		return 1;
311 
312 	/* check padding content */
313 	if (so->opt.flags & CAN_ISOTP_CHK_PAD_DATA) {
314 		for (i = start_index; i < cf->len; i++)
315 			if (cf->data[i] != content)
316 				return 1;
317 	}
318 	return 0;
319 }
320 
321 static int isotp_rcv_fc(struct isotp_sock *so, struct canfd_frame *cf, int ae)
322 {
323 	struct sock *sk = &so->sk;
324 
325 	if (so->tx.state != ISOTP_WAIT_FC &&
326 	    so->tx.state != ISOTP_WAIT_FIRST_FC)
327 		return 0;
328 
329 	hrtimer_cancel(&so->txtimer);
330 
331 	if ((cf->len < ae + FC_CONTENT_SZ) ||
332 	    ((so->opt.flags & ISOTP_CHECK_PADDING) &&
333 	     check_pad(so, cf, ae + FC_CONTENT_SZ, so->opt.rxpad_content))) {
334 		/* malformed PDU - report 'not a data message' */
335 		sk->sk_err = EBADMSG;
336 		if (!sock_flag(sk, SOCK_DEAD))
337 			sk->sk_error_report(sk);
338 
339 		so->tx.state = ISOTP_IDLE;
340 		wake_up_interruptible(&so->wait);
341 		return 1;
342 	}
343 
344 	/* get communication parameters only from the first FC frame */
345 	if (so->tx.state == ISOTP_WAIT_FIRST_FC) {
346 		so->txfc.bs = cf->data[ae + 1];
347 		so->txfc.stmin = cf->data[ae + 2];
348 
349 		/* fix wrong STmin values according spec */
350 		if (so->txfc.stmin > 0x7F &&
351 		    (so->txfc.stmin < 0xF1 || so->txfc.stmin > 0xF9))
352 			so->txfc.stmin = 0x7F;
353 
354 		so->tx_gap = ktime_set(0, 0);
355 		/* add transmission time for CAN frame N_As */
356 		so->tx_gap = ktime_add_ns(so->tx_gap, so->opt.frame_txtime);
357 		/* add waiting time for consecutive frames N_Cs */
358 		if (so->opt.flags & CAN_ISOTP_FORCE_TXSTMIN)
359 			so->tx_gap = ktime_add_ns(so->tx_gap,
360 						  so->force_tx_stmin);
361 		else if (so->txfc.stmin < 0x80)
362 			so->tx_gap = ktime_add_ns(so->tx_gap,
363 						  so->txfc.stmin * 1000000);
364 		else
365 			so->tx_gap = ktime_add_ns(so->tx_gap,
366 						  (so->txfc.stmin - 0xF0)
367 						  * 100000);
368 		so->tx.state = ISOTP_WAIT_FC;
369 	}
370 
371 	switch (cf->data[ae] & 0x0F) {
372 	case ISOTP_FC_CTS:
373 		so->tx.bs = 0;
374 		so->tx.state = ISOTP_SENDING;
375 		/* start cyclic timer for sending CF frame */
376 		hrtimer_start(&so->txtimer, so->tx_gap,
377 			      HRTIMER_MODE_REL_SOFT);
378 		break;
379 
380 	case ISOTP_FC_WT:
381 		/* start timer to wait for next FC frame */
382 		hrtimer_start(&so->txtimer, ktime_set(1, 0),
383 			      HRTIMER_MODE_REL_SOFT);
384 		break;
385 
386 	case ISOTP_FC_OVFLW:
387 		/* overflow on receiver side - report 'message too long' */
388 		sk->sk_err = EMSGSIZE;
389 		if (!sock_flag(sk, SOCK_DEAD))
390 			sk->sk_error_report(sk);
391 		fallthrough;
392 
393 	default:
394 		/* stop this tx job */
395 		so->tx.state = ISOTP_IDLE;
396 		wake_up_interruptible(&so->wait);
397 	}
398 	return 0;
399 }
400 
401 static int isotp_rcv_sf(struct sock *sk, struct canfd_frame *cf, int pcilen,
402 			struct sk_buff *skb, int len)
403 {
404 	struct isotp_sock *so = isotp_sk(sk);
405 	struct sk_buff *nskb;
406 
407 	hrtimer_cancel(&so->rxtimer);
408 	so->rx.state = ISOTP_IDLE;
409 
410 	if (!len || len > cf->len - pcilen)
411 		return 1;
412 
413 	if ((so->opt.flags & ISOTP_CHECK_PADDING) &&
414 	    check_pad(so, cf, pcilen + len, so->opt.rxpad_content)) {
415 		/* malformed PDU - report 'not a data message' */
416 		sk->sk_err = EBADMSG;
417 		if (!sock_flag(sk, SOCK_DEAD))
418 			sk->sk_error_report(sk);
419 		return 1;
420 	}
421 
422 	nskb = alloc_skb(len, gfp_any());
423 	if (!nskb)
424 		return 1;
425 
426 	memcpy(skb_put(nskb, len), &cf->data[pcilen], len);
427 
428 	nskb->tstamp = skb->tstamp;
429 	nskb->dev = skb->dev;
430 	isotp_rcv_skb(nskb, sk);
431 	return 0;
432 }
433 
434 static int isotp_rcv_ff(struct sock *sk, struct canfd_frame *cf, int ae)
435 {
436 	struct isotp_sock *so = isotp_sk(sk);
437 	int i;
438 	int off;
439 	int ff_pci_sz;
440 
441 	hrtimer_cancel(&so->rxtimer);
442 	so->rx.state = ISOTP_IDLE;
443 
444 	/* get the used sender LL_DL from the (first) CAN frame data length */
445 	so->rx.ll_dl = padlen(cf->len);
446 
447 	/* the first frame has to use the entire frame up to LL_DL length */
448 	if (cf->len != so->rx.ll_dl)
449 		return 1;
450 
451 	/* get the FF_DL */
452 	so->rx.len = (cf->data[ae] & 0x0F) << 8;
453 	so->rx.len += cf->data[ae + 1];
454 
455 	/* Check for FF_DL escape sequence supporting 32 bit PDU length */
456 	if (so->rx.len) {
457 		ff_pci_sz = FF_PCI_SZ12;
458 	} else {
459 		/* FF_DL = 0 => get real length from next 4 bytes */
460 		so->rx.len = cf->data[ae + 2] << 24;
461 		so->rx.len += cf->data[ae + 3] << 16;
462 		so->rx.len += cf->data[ae + 4] << 8;
463 		so->rx.len += cf->data[ae + 5];
464 		ff_pci_sz = FF_PCI_SZ32;
465 	}
466 
467 	/* take care of a potential SF_DL ESC offset for TX_DL > 8 */
468 	off = (so->rx.ll_dl > CAN_MAX_DLEN) ? 1 : 0;
469 
470 	if (so->rx.len + ae + off + ff_pci_sz < so->rx.ll_dl)
471 		return 1;
472 
473 	if (so->rx.len > MAX_MSG_LENGTH) {
474 		/* send FC frame with overflow status */
475 		isotp_send_fc(sk, ae, ISOTP_FC_OVFLW);
476 		return 1;
477 	}
478 
479 	/* copy the first received data bytes */
480 	so->rx.idx = 0;
481 	for (i = ae + ff_pci_sz; i < so->rx.ll_dl; i++)
482 		so->rx.buf[so->rx.idx++] = cf->data[i];
483 
484 	/* initial setup for this pdu reception */
485 	so->rx.sn = 1;
486 	so->rx.state = ISOTP_WAIT_DATA;
487 
488 	/* no creation of flow control frames */
489 	if (so->opt.flags & CAN_ISOTP_LISTEN_MODE)
490 		return 0;
491 
492 	/* send our first FC frame */
493 	isotp_send_fc(sk, ae, ISOTP_FC_CTS);
494 	return 0;
495 }
496 
497 static int isotp_rcv_cf(struct sock *sk, struct canfd_frame *cf, int ae,
498 			struct sk_buff *skb)
499 {
500 	struct isotp_sock *so = isotp_sk(sk);
501 	struct sk_buff *nskb;
502 	int i;
503 
504 	if (so->rx.state != ISOTP_WAIT_DATA)
505 		return 0;
506 
507 	/* drop if timestamp gap is less than force_rx_stmin nano secs */
508 	if (so->opt.flags & CAN_ISOTP_FORCE_RXSTMIN) {
509 		if (ktime_to_ns(ktime_sub(skb->tstamp, so->lastrxcf_tstamp)) <
510 		    so->force_rx_stmin)
511 			return 0;
512 
513 		so->lastrxcf_tstamp = skb->tstamp;
514 	}
515 
516 	hrtimer_cancel(&so->rxtimer);
517 
518 	/* CFs are never longer than the FF */
519 	if (cf->len > so->rx.ll_dl)
520 		return 1;
521 
522 	/* CFs have usually the LL_DL length */
523 	if (cf->len < so->rx.ll_dl) {
524 		/* this is only allowed for the last CF */
525 		if (so->rx.len - so->rx.idx > so->rx.ll_dl - ae - N_PCI_SZ)
526 			return 1;
527 	}
528 
529 	if ((cf->data[ae] & 0x0F) != so->rx.sn) {
530 		/* wrong sn detected - report 'illegal byte sequence' */
531 		sk->sk_err = EILSEQ;
532 		if (!sock_flag(sk, SOCK_DEAD))
533 			sk->sk_error_report(sk);
534 
535 		/* reset rx state */
536 		so->rx.state = ISOTP_IDLE;
537 		return 1;
538 	}
539 	so->rx.sn++;
540 	so->rx.sn %= 16;
541 
542 	for (i = ae + N_PCI_SZ; i < cf->len; i++) {
543 		so->rx.buf[so->rx.idx++] = cf->data[i];
544 		if (so->rx.idx >= so->rx.len)
545 			break;
546 	}
547 
548 	if (so->rx.idx >= so->rx.len) {
549 		/* we are done */
550 		so->rx.state = ISOTP_IDLE;
551 
552 		if ((so->opt.flags & ISOTP_CHECK_PADDING) &&
553 		    check_pad(so, cf, i + 1, so->opt.rxpad_content)) {
554 			/* malformed PDU - report 'not a data message' */
555 			sk->sk_err = EBADMSG;
556 			if (!sock_flag(sk, SOCK_DEAD))
557 				sk->sk_error_report(sk);
558 			return 1;
559 		}
560 
561 		nskb = alloc_skb(so->rx.len, gfp_any());
562 		if (!nskb)
563 			return 1;
564 
565 		memcpy(skb_put(nskb, so->rx.len), so->rx.buf,
566 		       so->rx.len);
567 
568 		nskb->tstamp = skb->tstamp;
569 		nskb->dev = skb->dev;
570 		isotp_rcv_skb(nskb, sk);
571 		return 0;
572 	}
573 
574 	/* perform blocksize handling, if enabled */
575 	if (!so->rxfc.bs || ++so->rx.bs < so->rxfc.bs) {
576 		/* start rx timeout watchdog */
577 		hrtimer_start(&so->rxtimer, ktime_set(1, 0),
578 			      HRTIMER_MODE_REL_SOFT);
579 		return 0;
580 	}
581 
582 	/* no creation of flow control frames */
583 	if (so->opt.flags & CAN_ISOTP_LISTEN_MODE)
584 		return 0;
585 
586 	/* we reached the specified blocksize so->rxfc.bs */
587 	isotp_send_fc(sk, ae, ISOTP_FC_CTS);
588 	return 0;
589 }
590 
591 static void isotp_rcv(struct sk_buff *skb, void *data)
592 {
593 	struct sock *sk = (struct sock *)data;
594 	struct isotp_sock *so = isotp_sk(sk);
595 	struct canfd_frame *cf;
596 	int ae = (so->opt.flags & CAN_ISOTP_EXTEND_ADDR) ? 1 : 0;
597 	u8 n_pci_type, sf_dl;
598 
599 	/* Strictly receive only frames with the configured MTU size
600 	 * => clear separation of CAN2.0 / CAN FD transport channels
601 	 */
602 	if (skb->len != so->ll.mtu)
603 		return;
604 
605 	cf = (struct canfd_frame *)skb->data;
606 
607 	/* if enabled: check reception of my configured extended address */
608 	if (ae && cf->data[0] != so->opt.rx_ext_address)
609 		return;
610 
611 	n_pci_type = cf->data[ae] & 0xF0;
612 
613 	if (so->opt.flags & CAN_ISOTP_HALF_DUPLEX) {
614 		/* check rx/tx path half duplex expectations */
615 		if ((so->tx.state != ISOTP_IDLE && n_pci_type != N_PCI_FC) ||
616 		    (so->rx.state != ISOTP_IDLE && n_pci_type == N_PCI_FC))
617 			return;
618 	}
619 
620 	switch (n_pci_type) {
621 	case N_PCI_FC:
622 		/* tx path: flow control frame containing the FC parameters */
623 		isotp_rcv_fc(so, cf, ae);
624 		break;
625 
626 	case N_PCI_SF:
627 		/* rx path: single frame
628 		 *
629 		 * As we do not have a rx.ll_dl configuration, we can only test
630 		 * if the CAN frames payload length matches the LL_DL == 8
631 		 * requirements - no matter if it's CAN 2.0 or CAN FD
632 		 */
633 
634 		/* get the SF_DL from the N_PCI byte */
635 		sf_dl = cf->data[ae] & 0x0F;
636 
637 		if (cf->len <= CAN_MAX_DLEN) {
638 			isotp_rcv_sf(sk, cf, SF_PCI_SZ4 + ae, skb, sf_dl);
639 		} else {
640 			if (skb->len == CANFD_MTU) {
641 				/* We have a CAN FD frame and CAN_DL is greater than 8:
642 				 * Only frames with the SF_DL == 0 ESC value are valid.
643 				 *
644 				 * If so take care of the increased SF PCI size
645 				 * (SF_PCI_SZ8) to point to the message content behind
646 				 * the extended SF PCI info and get the real SF_DL
647 				 * length value from the formerly first data byte.
648 				 */
649 				if (sf_dl == 0)
650 					isotp_rcv_sf(sk, cf, SF_PCI_SZ8 + ae, skb,
651 						     cf->data[SF_PCI_SZ4 + ae]);
652 			}
653 		}
654 		break;
655 
656 	case N_PCI_FF:
657 		/* rx path: first frame */
658 		isotp_rcv_ff(sk, cf, ae);
659 		break;
660 
661 	case N_PCI_CF:
662 		/* rx path: consecutive frame */
663 		isotp_rcv_cf(sk, cf, ae, skb);
664 		break;
665 	}
666 }
667 
668 static void isotp_fill_dataframe(struct canfd_frame *cf, struct isotp_sock *so,
669 				 int ae, int off)
670 {
671 	int pcilen = N_PCI_SZ + ae + off;
672 	int space = so->tx.ll_dl - pcilen;
673 	int num = min_t(int, so->tx.len - so->tx.idx, space);
674 	int i;
675 
676 	cf->can_id = so->txid;
677 	cf->len = num + pcilen;
678 
679 	if (num < space) {
680 		if (so->opt.flags & CAN_ISOTP_TX_PADDING) {
681 			/* user requested padding */
682 			cf->len = padlen(cf->len);
683 			memset(cf->data, so->opt.txpad_content, cf->len);
684 		} else if (cf->len > CAN_MAX_DLEN) {
685 			/* mandatory padding for CAN FD frames */
686 			cf->len = padlen(cf->len);
687 			memset(cf->data, CAN_ISOTP_DEFAULT_PAD_CONTENT,
688 			       cf->len);
689 		}
690 	}
691 
692 	for (i = 0; i < num; i++)
693 		cf->data[pcilen + i] = so->tx.buf[so->tx.idx++];
694 
695 	if (ae)
696 		cf->data[0] = so->opt.ext_address;
697 }
698 
699 static void isotp_create_fframe(struct canfd_frame *cf, struct isotp_sock *so,
700 				int ae)
701 {
702 	int i;
703 	int ff_pci_sz;
704 
705 	cf->can_id = so->txid;
706 	cf->len = so->tx.ll_dl;
707 	if (ae)
708 		cf->data[0] = so->opt.ext_address;
709 
710 	/* create N_PCI bytes with 12/32 bit FF_DL data length */
711 	if (so->tx.len > 4095) {
712 		/* use 32 bit FF_DL notation */
713 		cf->data[ae] = N_PCI_FF;
714 		cf->data[ae + 1] = 0;
715 		cf->data[ae + 2] = (u8)(so->tx.len >> 24) & 0xFFU;
716 		cf->data[ae + 3] = (u8)(so->tx.len >> 16) & 0xFFU;
717 		cf->data[ae + 4] = (u8)(so->tx.len >> 8) & 0xFFU;
718 		cf->data[ae + 5] = (u8)so->tx.len & 0xFFU;
719 		ff_pci_sz = FF_PCI_SZ32;
720 	} else {
721 		/* use 12 bit FF_DL notation */
722 		cf->data[ae] = (u8)(so->tx.len >> 8) | N_PCI_FF;
723 		cf->data[ae + 1] = (u8)so->tx.len & 0xFFU;
724 		ff_pci_sz = FF_PCI_SZ12;
725 	}
726 
727 	/* add first data bytes depending on ae */
728 	for (i = ae + ff_pci_sz; i < so->tx.ll_dl; i++)
729 		cf->data[i] = so->tx.buf[so->tx.idx++];
730 
731 	so->tx.sn = 1;
732 	so->tx.state = ISOTP_WAIT_FIRST_FC;
733 }
734 
735 static enum hrtimer_restart isotp_tx_timer_handler(struct hrtimer *hrtimer)
736 {
737 	struct isotp_sock *so = container_of(hrtimer, struct isotp_sock,
738 					     txtimer);
739 	struct sock *sk = &so->sk;
740 	struct sk_buff *skb;
741 	struct net_device *dev;
742 	struct canfd_frame *cf;
743 	enum hrtimer_restart restart = HRTIMER_NORESTART;
744 	int can_send_ret;
745 	int ae = (so->opt.flags & CAN_ISOTP_EXTEND_ADDR) ? 1 : 0;
746 
747 	switch (so->tx.state) {
748 	case ISOTP_WAIT_FC:
749 	case ISOTP_WAIT_FIRST_FC:
750 
751 		/* we did not get any flow control frame in time */
752 
753 		/* report 'communication error on send' */
754 		sk->sk_err = ECOMM;
755 		if (!sock_flag(sk, SOCK_DEAD))
756 			sk->sk_error_report(sk);
757 
758 		/* reset tx state */
759 		so->tx.state = ISOTP_IDLE;
760 		wake_up_interruptible(&so->wait);
761 		break;
762 
763 	case ISOTP_SENDING:
764 
765 		/* push out the next segmented pdu */
766 		dev = dev_get_by_index(sock_net(sk), so->ifindex);
767 		if (!dev)
768 			break;
769 
770 isotp_tx_burst:
771 		skb = alloc_skb(so->ll.mtu + sizeof(struct can_skb_priv),
772 				GFP_ATOMIC);
773 		if (!skb) {
774 			dev_put(dev);
775 			break;
776 		}
777 
778 		can_skb_reserve(skb);
779 		can_skb_prv(skb)->ifindex = dev->ifindex;
780 		can_skb_prv(skb)->skbcnt = 0;
781 
782 		cf = (struct canfd_frame *)skb->data;
783 		skb_put(skb, so->ll.mtu);
784 
785 		/* create consecutive frame */
786 		isotp_fill_dataframe(cf, so, ae, 0);
787 
788 		/* place consecutive frame N_PCI in appropriate index */
789 		cf->data[ae] = N_PCI_CF | so->tx.sn++;
790 		so->tx.sn %= 16;
791 		so->tx.bs++;
792 
793 		if (so->ll.mtu == CANFD_MTU)
794 			cf->flags = so->ll.tx_flags;
795 
796 		skb->dev = dev;
797 		can_skb_set_owner(skb, sk);
798 
799 		can_send_ret = can_send(skb, 1);
800 		if (can_send_ret)
801 			pr_notice_once("can-isotp: %s: can_send_ret %d\n",
802 				       __func__, can_send_ret);
803 
804 		if (so->tx.idx >= so->tx.len) {
805 			/* we are done */
806 			so->tx.state = ISOTP_IDLE;
807 			dev_put(dev);
808 			wake_up_interruptible(&so->wait);
809 			break;
810 		}
811 
812 		if (so->txfc.bs && so->tx.bs >= so->txfc.bs) {
813 			/* stop and wait for FC */
814 			so->tx.state = ISOTP_WAIT_FC;
815 			dev_put(dev);
816 			hrtimer_set_expires(&so->txtimer,
817 					    ktime_add(ktime_get(),
818 						      ktime_set(1, 0)));
819 			restart = HRTIMER_RESTART;
820 			break;
821 		}
822 
823 		/* no gap between data frames needed => use burst mode */
824 		if (!so->tx_gap)
825 			goto isotp_tx_burst;
826 
827 		/* start timer to send next data frame with correct delay */
828 		dev_put(dev);
829 		hrtimer_set_expires(&so->txtimer,
830 				    ktime_add(ktime_get(), so->tx_gap));
831 		restart = HRTIMER_RESTART;
832 		break;
833 
834 	default:
835 		WARN_ON_ONCE(1);
836 	}
837 
838 	return restart;
839 }
840 
841 static int isotp_sendmsg(struct socket *sock, struct msghdr *msg, size_t size)
842 {
843 	struct sock *sk = sock->sk;
844 	struct isotp_sock *so = isotp_sk(sk);
845 	struct sk_buff *skb;
846 	struct net_device *dev;
847 	struct canfd_frame *cf;
848 	int ae = (so->opt.flags & CAN_ISOTP_EXTEND_ADDR) ? 1 : 0;
849 	int wait_tx_done = (so->opt.flags & CAN_ISOTP_WAIT_TX_DONE) ? 1 : 0;
850 	int off;
851 	int err;
852 
853 	if (!so->bound)
854 		return -EADDRNOTAVAIL;
855 
856 	/* we do not support multiple buffers - for now */
857 	if (so->tx.state != ISOTP_IDLE || wq_has_sleeper(&so->wait)) {
858 		if (msg->msg_flags & MSG_DONTWAIT)
859 			return -EAGAIN;
860 
861 		/* wait for complete transmission of current pdu */
862 		wait_event_interruptible(so->wait, so->tx.state == ISOTP_IDLE);
863 	}
864 
865 	if (!size || size > MAX_MSG_LENGTH)
866 		return -EINVAL;
867 
868 	/* take care of a potential SF_DL ESC offset for TX_DL > 8 */
869 	off = (so->tx.ll_dl > CAN_MAX_DLEN) ? 1 : 0;
870 
871 	/* does the given data fit into a single frame for SF_BROADCAST? */
872 	if ((so->opt.flags & CAN_ISOTP_SF_BROADCAST) &&
873 	    (size > so->tx.ll_dl - SF_PCI_SZ4 - ae - off))
874 		return -EINVAL;
875 
876 	err = memcpy_from_msg(so->tx.buf, msg, size);
877 	if (err < 0)
878 		return err;
879 
880 	dev = dev_get_by_index(sock_net(sk), so->ifindex);
881 	if (!dev)
882 		return -ENXIO;
883 
884 	skb = sock_alloc_send_skb(sk, so->ll.mtu + sizeof(struct can_skb_priv),
885 				  msg->msg_flags & MSG_DONTWAIT, &err);
886 	if (!skb) {
887 		dev_put(dev);
888 		return err;
889 	}
890 
891 	can_skb_reserve(skb);
892 	can_skb_prv(skb)->ifindex = dev->ifindex;
893 	can_skb_prv(skb)->skbcnt = 0;
894 
895 	so->tx.state = ISOTP_SENDING;
896 	so->tx.len = size;
897 	so->tx.idx = 0;
898 
899 	cf = (struct canfd_frame *)skb->data;
900 	skb_put(skb, so->ll.mtu);
901 
902 	/* check for single frame transmission depending on TX_DL */
903 	if (size <= so->tx.ll_dl - SF_PCI_SZ4 - ae - off) {
904 		/* The message size generally fits into a SingleFrame - good.
905 		 *
906 		 * SF_DL ESC offset optimization:
907 		 *
908 		 * When TX_DL is greater 8 but the message would still fit
909 		 * into a 8 byte CAN frame, we can omit the offset.
910 		 * This prevents a protocol caused length extension from
911 		 * CAN_DL = 8 to CAN_DL = 12 due to the SF_SL ESC handling.
912 		 */
913 		if (size <= CAN_MAX_DLEN - SF_PCI_SZ4 - ae)
914 			off = 0;
915 
916 		isotp_fill_dataframe(cf, so, ae, off);
917 
918 		/* place single frame N_PCI w/o length in appropriate index */
919 		cf->data[ae] = N_PCI_SF;
920 
921 		/* place SF_DL size value depending on the SF_DL ESC offset */
922 		if (off)
923 			cf->data[SF_PCI_SZ4 + ae] = size;
924 		else
925 			cf->data[ae] |= size;
926 
927 		so->tx.state = ISOTP_IDLE;
928 		wake_up_interruptible(&so->wait);
929 
930 		/* don't enable wait queue for a single frame transmission */
931 		wait_tx_done = 0;
932 	} else {
933 		/* send first frame and wait for FC */
934 
935 		isotp_create_fframe(cf, so, ae);
936 
937 		/* start timeout for FC */
938 		hrtimer_start(&so->txtimer, ktime_set(1, 0), HRTIMER_MODE_REL_SOFT);
939 	}
940 
941 	/* send the first or only CAN frame */
942 	if (so->ll.mtu == CANFD_MTU)
943 		cf->flags = so->ll.tx_flags;
944 
945 	skb->dev = dev;
946 	skb->sk = sk;
947 	err = can_send(skb, 1);
948 	dev_put(dev);
949 	if (err) {
950 		pr_notice_once("can-isotp: %s: can_send_ret %d\n",
951 			       __func__, err);
952 		return err;
953 	}
954 
955 	if (wait_tx_done) {
956 		/* wait for complete transmission of current pdu */
957 		wait_event_interruptible(so->wait, so->tx.state == ISOTP_IDLE);
958 	}
959 
960 	return size;
961 }
962 
963 static int isotp_recvmsg(struct socket *sock, struct msghdr *msg, size_t size,
964 			 int flags)
965 {
966 	struct sock *sk = sock->sk;
967 	struct sk_buff *skb;
968 	int err = 0;
969 	int noblock;
970 
971 	noblock = flags & MSG_DONTWAIT;
972 	flags &= ~MSG_DONTWAIT;
973 
974 	skb = skb_recv_datagram(sk, flags, noblock, &err);
975 	if (!skb)
976 		return err;
977 
978 	if (size < skb->len)
979 		msg->msg_flags |= MSG_TRUNC;
980 	else
981 		size = skb->len;
982 
983 	err = memcpy_to_msg(msg, skb->data, size);
984 	if (err < 0) {
985 		skb_free_datagram(sk, skb);
986 		return err;
987 	}
988 
989 	sock_recv_timestamp(msg, sk, skb);
990 
991 	if (msg->msg_name) {
992 		msg->msg_namelen = sizeof(struct sockaddr_can);
993 		memcpy(msg->msg_name, skb->cb, msg->msg_namelen);
994 	}
995 
996 	skb_free_datagram(sk, skb);
997 
998 	return size;
999 }
1000 
1001 static int isotp_release(struct socket *sock)
1002 {
1003 	struct sock *sk = sock->sk;
1004 	struct isotp_sock *so;
1005 	struct net *net;
1006 
1007 	if (!sk)
1008 		return 0;
1009 
1010 	so = isotp_sk(sk);
1011 	net = sock_net(sk);
1012 
1013 	/* wait for complete transmission of current pdu */
1014 	wait_event_interruptible(so->wait, so->tx.state == ISOTP_IDLE);
1015 
1016 	unregister_netdevice_notifier(&so->notifier);
1017 
1018 	lock_sock(sk);
1019 
1020 	hrtimer_cancel(&so->txtimer);
1021 	hrtimer_cancel(&so->rxtimer);
1022 
1023 	/* remove current filters & unregister */
1024 	if (so->bound && (!(so->opt.flags & CAN_ISOTP_SF_BROADCAST))) {
1025 		if (so->ifindex) {
1026 			struct net_device *dev;
1027 
1028 			dev = dev_get_by_index(net, so->ifindex);
1029 			if (dev) {
1030 				can_rx_unregister(net, dev, so->rxid,
1031 						  SINGLE_MASK(so->rxid),
1032 						  isotp_rcv, sk);
1033 				dev_put(dev);
1034 			}
1035 		}
1036 	}
1037 
1038 	so->ifindex = 0;
1039 	so->bound = 0;
1040 
1041 	sock_orphan(sk);
1042 	sock->sk = NULL;
1043 
1044 	release_sock(sk);
1045 	sock_put(sk);
1046 
1047 	return 0;
1048 }
1049 
1050 static int isotp_bind(struct socket *sock, struct sockaddr *uaddr, int len)
1051 {
1052 	struct sockaddr_can *addr = (struct sockaddr_can *)uaddr;
1053 	struct sock *sk = sock->sk;
1054 	struct isotp_sock *so = isotp_sk(sk);
1055 	struct net *net = sock_net(sk);
1056 	int ifindex;
1057 	struct net_device *dev;
1058 	int err = 0;
1059 	int notify_enetdown = 0;
1060 	int do_rx_reg = 1;
1061 
1062 	if (len < CAN_REQUIRED_SIZE(struct sockaddr_can, can_addr.tp))
1063 		return -EINVAL;
1064 
1065 	/* do not register frame reception for functional addressing */
1066 	if (so->opt.flags & CAN_ISOTP_SF_BROADCAST)
1067 		do_rx_reg = 0;
1068 
1069 	/* do not validate rx address for functional addressing */
1070 	if (do_rx_reg) {
1071 		if (addr->can_addr.tp.rx_id == addr->can_addr.tp.tx_id)
1072 			return -EADDRNOTAVAIL;
1073 
1074 		if (addr->can_addr.tp.rx_id & (CAN_ERR_FLAG | CAN_RTR_FLAG))
1075 			return -EADDRNOTAVAIL;
1076 	}
1077 
1078 	if (addr->can_addr.tp.tx_id & (CAN_ERR_FLAG | CAN_RTR_FLAG))
1079 		return -EADDRNOTAVAIL;
1080 
1081 	if (!addr->can_ifindex)
1082 		return -ENODEV;
1083 
1084 	lock_sock(sk);
1085 
1086 	if (so->bound && addr->can_ifindex == so->ifindex &&
1087 	    addr->can_addr.tp.rx_id == so->rxid &&
1088 	    addr->can_addr.tp.tx_id == so->txid)
1089 		goto out;
1090 
1091 	dev = dev_get_by_index(net, addr->can_ifindex);
1092 	if (!dev) {
1093 		err = -ENODEV;
1094 		goto out;
1095 	}
1096 	if (dev->type != ARPHRD_CAN) {
1097 		dev_put(dev);
1098 		err = -ENODEV;
1099 		goto out;
1100 	}
1101 	if (dev->mtu < so->ll.mtu) {
1102 		dev_put(dev);
1103 		err = -EINVAL;
1104 		goto out;
1105 	}
1106 	if (!(dev->flags & IFF_UP))
1107 		notify_enetdown = 1;
1108 
1109 	ifindex = dev->ifindex;
1110 
1111 	if (do_rx_reg)
1112 		can_rx_register(net, dev, addr->can_addr.tp.rx_id,
1113 				SINGLE_MASK(addr->can_addr.tp.rx_id),
1114 				isotp_rcv, sk, "isotp", sk);
1115 
1116 	dev_put(dev);
1117 
1118 	if (so->bound && do_rx_reg) {
1119 		/* unregister old filter */
1120 		if (so->ifindex) {
1121 			dev = dev_get_by_index(net, so->ifindex);
1122 			if (dev) {
1123 				can_rx_unregister(net, dev, so->rxid,
1124 						  SINGLE_MASK(so->rxid),
1125 						  isotp_rcv, sk);
1126 				dev_put(dev);
1127 			}
1128 		}
1129 	}
1130 
1131 	/* switch to new settings */
1132 	so->ifindex = ifindex;
1133 	so->rxid = addr->can_addr.tp.rx_id;
1134 	so->txid = addr->can_addr.tp.tx_id;
1135 	so->bound = 1;
1136 
1137 out:
1138 	release_sock(sk);
1139 
1140 	if (notify_enetdown) {
1141 		sk->sk_err = ENETDOWN;
1142 		if (!sock_flag(sk, SOCK_DEAD))
1143 			sk->sk_error_report(sk);
1144 	}
1145 
1146 	return err;
1147 }
1148 
1149 static int isotp_getname(struct socket *sock, struct sockaddr *uaddr, int peer)
1150 {
1151 	struct sockaddr_can *addr = (struct sockaddr_can *)uaddr;
1152 	struct sock *sk = sock->sk;
1153 	struct isotp_sock *so = isotp_sk(sk);
1154 
1155 	if (peer)
1156 		return -EOPNOTSUPP;
1157 
1158 	addr->can_family = AF_CAN;
1159 	addr->can_ifindex = so->ifindex;
1160 	addr->can_addr.tp.rx_id = so->rxid;
1161 	addr->can_addr.tp.tx_id = so->txid;
1162 
1163 	return sizeof(*addr);
1164 }
1165 
1166 static int isotp_setsockopt(struct socket *sock, int level, int optname,
1167 			    sockptr_t optval, unsigned int optlen)
1168 {
1169 	struct sock *sk = sock->sk;
1170 	struct isotp_sock *so = isotp_sk(sk);
1171 	int ret = 0;
1172 
1173 	if (level != SOL_CAN_ISOTP)
1174 		return -EINVAL;
1175 
1176 	if (so->bound)
1177 		return -EISCONN;
1178 
1179 	switch (optname) {
1180 	case CAN_ISOTP_OPTS:
1181 		if (optlen != sizeof(struct can_isotp_options))
1182 			return -EINVAL;
1183 
1184 		if (copy_from_sockptr(&so->opt, optval, optlen))
1185 			return -EFAULT;
1186 
1187 		/* no separate rx_ext_address is given => use ext_address */
1188 		if (!(so->opt.flags & CAN_ISOTP_RX_EXT_ADDR))
1189 			so->opt.rx_ext_address = so->opt.ext_address;
1190 		break;
1191 
1192 	case CAN_ISOTP_RECV_FC:
1193 		if (optlen != sizeof(struct can_isotp_fc_options))
1194 			return -EINVAL;
1195 
1196 		if (copy_from_sockptr(&so->rxfc, optval, optlen))
1197 			return -EFAULT;
1198 		break;
1199 
1200 	case CAN_ISOTP_TX_STMIN:
1201 		if (optlen != sizeof(u32))
1202 			return -EINVAL;
1203 
1204 		if (copy_from_sockptr(&so->force_tx_stmin, optval, optlen))
1205 			return -EFAULT;
1206 		break;
1207 
1208 	case CAN_ISOTP_RX_STMIN:
1209 		if (optlen != sizeof(u32))
1210 			return -EINVAL;
1211 
1212 		if (copy_from_sockptr(&so->force_rx_stmin, optval, optlen))
1213 			return -EFAULT;
1214 		break;
1215 
1216 	case CAN_ISOTP_LL_OPTS:
1217 		if (optlen == sizeof(struct can_isotp_ll_options)) {
1218 			struct can_isotp_ll_options ll;
1219 
1220 			if (copy_from_sockptr(&ll, optval, optlen))
1221 				return -EFAULT;
1222 
1223 			/* check for correct ISO 11898-1 DLC data length */
1224 			if (ll.tx_dl != padlen(ll.tx_dl))
1225 				return -EINVAL;
1226 
1227 			if (ll.mtu != CAN_MTU && ll.mtu != CANFD_MTU)
1228 				return -EINVAL;
1229 
1230 			if (ll.mtu == CAN_MTU && ll.tx_dl > CAN_MAX_DLEN)
1231 				return -EINVAL;
1232 
1233 			memcpy(&so->ll, &ll, sizeof(ll));
1234 
1235 			/* set ll_dl for tx path to similar place as for rx */
1236 			so->tx.ll_dl = ll.tx_dl;
1237 		} else {
1238 			return -EINVAL;
1239 		}
1240 		break;
1241 
1242 	default:
1243 		ret = -ENOPROTOOPT;
1244 	}
1245 
1246 	return ret;
1247 }
1248 
1249 static int isotp_getsockopt(struct socket *sock, int level, int optname,
1250 			    char __user *optval, int __user *optlen)
1251 {
1252 	struct sock *sk = sock->sk;
1253 	struct isotp_sock *so = isotp_sk(sk);
1254 	int len;
1255 	void *val;
1256 
1257 	if (level != SOL_CAN_ISOTP)
1258 		return -EINVAL;
1259 	if (get_user(len, optlen))
1260 		return -EFAULT;
1261 	if (len < 0)
1262 		return -EINVAL;
1263 
1264 	switch (optname) {
1265 	case CAN_ISOTP_OPTS:
1266 		len = min_t(int, len, sizeof(struct can_isotp_options));
1267 		val = &so->opt;
1268 		break;
1269 
1270 	case CAN_ISOTP_RECV_FC:
1271 		len = min_t(int, len, sizeof(struct can_isotp_fc_options));
1272 		val = &so->rxfc;
1273 		break;
1274 
1275 	case CAN_ISOTP_TX_STMIN:
1276 		len = min_t(int, len, sizeof(u32));
1277 		val = &so->force_tx_stmin;
1278 		break;
1279 
1280 	case CAN_ISOTP_RX_STMIN:
1281 		len = min_t(int, len, sizeof(u32));
1282 		val = &so->force_rx_stmin;
1283 		break;
1284 
1285 	case CAN_ISOTP_LL_OPTS:
1286 		len = min_t(int, len, sizeof(struct can_isotp_ll_options));
1287 		val = &so->ll;
1288 		break;
1289 
1290 	default:
1291 		return -ENOPROTOOPT;
1292 	}
1293 
1294 	if (put_user(len, optlen))
1295 		return -EFAULT;
1296 	if (copy_to_user(optval, val, len))
1297 		return -EFAULT;
1298 	return 0;
1299 }
1300 
1301 static int isotp_notifier(struct notifier_block *nb, unsigned long msg,
1302 			  void *ptr)
1303 {
1304 	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
1305 	struct isotp_sock *so = container_of(nb, struct isotp_sock, notifier);
1306 	struct sock *sk = &so->sk;
1307 
1308 	if (!net_eq(dev_net(dev), sock_net(sk)))
1309 		return NOTIFY_DONE;
1310 
1311 	if (dev->type != ARPHRD_CAN)
1312 		return NOTIFY_DONE;
1313 
1314 	if (so->ifindex != dev->ifindex)
1315 		return NOTIFY_DONE;
1316 
1317 	switch (msg) {
1318 	case NETDEV_UNREGISTER:
1319 		lock_sock(sk);
1320 		/* remove current filters & unregister */
1321 		if (so->bound && (!(so->opt.flags & CAN_ISOTP_SF_BROADCAST)))
1322 			can_rx_unregister(dev_net(dev), dev, so->rxid,
1323 					  SINGLE_MASK(so->rxid),
1324 					  isotp_rcv, sk);
1325 
1326 		so->ifindex = 0;
1327 		so->bound  = 0;
1328 		release_sock(sk);
1329 
1330 		sk->sk_err = ENODEV;
1331 		if (!sock_flag(sk, SOCK_DEAD))
1332 			sk->sk_error_report(sk);
1333 		break;
1334 
1335 	case NETDEV_DOWN:
1336 		sk->sk_err = ENETDOWN;
1337 		if (!sock_flag(sk, SOCK_DEAD))
1338 			sk->sk_error_report(sk);
1339 		break;
1340 	}
1341 
1342 	return NOTIFY_DONE;
1343 }
1344 
1345 static int isotp_init(struct sock *sk)
1346 {
1347 	struct isotp_sock *so = isotp_sk(sk);
1348 
1349 	so->ifindex = 0;
1350 	so->bound = 0;
1351 
1352 	so->opt.flags = CAN_ISOTP_DEFAULT_FLAGS;
1353 	so->opt.ext_address = CAN_ISOTP_DEFAULT_EXT_ADDRESS;
1354 	so->opt.rx_ext_address = CAN_ISOTP_DEFAULT_EXT_ADDRESS;
1355 	so->opt.rxpad_content = CAN_ISOTP_DEFAULT_PAD_CONTENT;
1356 	so->opt.txpad_content = CAN_ISOTP_DEFAULT_PAD_CONTENT;
1357 	so->opt.frame_txtime = CAN_ISOTP_DEFAULT_FRAME_TXTIME;
1358 	so->rxfc.bs = CAN_ISOTP_DEFAULT_RECV_BS;
1359 	so->rxfc.stmin = CAN_ISOTP_DEFAULT_RECV_STMIN;
1360 	so->rxfc.wftmax = CAN_ISOTP_DEFAULT_RECV_WFTMAX;
1361 	so->ll.mtu = CAN_ISOTP_DEFAULT_LL_MTU;
1362 	so->ll.tx_dl = CAN_ISOTP_DEFAULT_LL_TX_DL;
1363 	so->ll.tx_flags = CAN_ISOTP_DEFAULT_LL_TX_FLAGS;
1364 
1365 	/* set ll_dl for tx path to similar place as for rx */
1366 	so->tx.ll_dl = so->ll.tx_dl;
1367 
1368 	so->rx.state = ISOTP_IDLE;
1369 	so->tx.state = ISOTP_IDLE;
1370 
1371 	hrtimer_init(&so->rxtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_SOFT);
1372 	so->rxtimer.function = isotp_rx_timer_handler;
1373 	hrtimer_init(&so->txtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_SOFT);
1374 	so->txtimer.function = isotp_tx_timer_handler;
1375 
1376 	init_waitqueue_head(&so->wait);
1377 
1378 	so->notifier.notifier_call = isotp_notifier;
1379 	register_netdevice_notifier(&so->notifier);
1380 
1381 	return 0;
1382 }
1383 
1384 static int isotp_sock_no_ioctlcmd(struct socket *sock, unsigned int cmd,
1385 				  unsigned long arg)
1386 {
1387 	/* no ioctls for socket layer -> hand it down to NIC layer */
1388 	return -ENOIOCTLCMD;
1389 }
1390 
1391 static const struct proto_ops isotp_ops = {
1392 	.family = PF_CAN,
1393 	.release = isotp_release,
1394 	.bind = isotp_bind,
1395 	.connect = sock_no_connect,
1396 	.socketpair = sock_no_socketpair,
1397 	.accept = sock_no_accept,
1398 	.getname = isotp_getname,
1399 	.poll = datagram_poll,
1400 	.ioctl = isotp_sock_no_ioctlcmd,
1401 	.gettstamp = sock_gettstamp,
1402 	.listen = sock_no_listen,
1403 	.shutdown = sock_no_shutdown,
1404 	.setsockopt = isotp_setsockopt,
1405 	.getsockopt = isotp_getsockopt,
1406 	.sendmsg = isotp_sendmsg,
1407 	.recvmsg = isotp_recvmsg,
1408 	.mmap = sock_no_mmap,
1409 	.sendpage = sock_no_sendpage,
1410 };
1411 
1412 static struct proto isotp_proto __read_mostly = {
1413 	.name = "CAN_ISOTP",
1414 	.owner = THIS_MODULE,
1415 	.obj_size = sizeof(struct isotp_sock),
1416 	.init = isotp_init,
1417 };
1418 
1419 static const struct can_proto isotp_can_proto = {
1420 	.type = SOCK_DGRAM,
1421 	.protocol = CAN_ISOTP,
1422 	.ops = &isotp_ops,
1423 	.prot = &isotp_proto,
1424 };
1425 
1426 static __init int isotp_module_init(void)
1427 {
1428 	int err;
1429 
1430 	pr_info("can: isotp protocol\n");
1431 
1432 	err = can_proto_register(&isotp_can_proto);
1433 	if (err < 0)
1434 		pr_err("can: registration of isotp protocol failed\n");
1435 
1436 	return err;
1437 }
1438 
1439 static __exit void isotp_module_exit(void)
1440 {
1441 	can_proto_unregister(&isotp_can_proto);
1442 }
1443 
1444 module_init(isotp_module_init);
1445 module_exit(isotp_module_exit);
1446