xref: /openbmc/linux/net/can/raw.c (revision 867a0e05)
1 /*
2  * raw.c - Raw sockets for protocol family CAN
3  *
4  * Copyright (c) 2002-2007 Volkswagen Group Electronic Research
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  * 3. Neither the name of Volkswagen nor the names of its contributors
16  *    may be used to endorse or promote products derived from this software
17  *    without specific prior written permission.
18  *
19  * Alternatively, provided that this notice is retained in full, this
20  * software may be distributed under the terms of the GNU General
21  * Public License ("GPL") version 2, in which case the provisions of the
22  * GPL apply INSTEAD OF those given above.
23  *
24  * The provided data structures and external interfaces from this code
25  * are not restricted to be used by modules with a GPL compatible license.
26  *
27  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
28  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
29  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
30  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
31  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
32  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
33  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
34  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
35  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
36  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
37  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
38  * DAMAGE.
39  *
40  */
41 
42 #include <linux/module.h>
43 #include <linux/init.h>
44 #include <linux/uio.h>
45 #include <linux/net.h>
46 #include <linux/slab.h>
47 #include <linux/netdevice.h>
48 #include <linux/socket.h>
49 #include <linux/if_arp.h>
50 #include <linux/skbuff.h>
51 #include <linux/can.h>
52 #include <linux/can/core.h>
53 #include <linux/can/skb.h>
54 #include <linux/can/raw.h>
55 #include <net/sock.h>
56 #include <net/net_namespace.h>
57 
58 #define CAN_RAW_VERSION CAN_VERSION
59 
60 MODULE_DESCRIPTION("PF_CAN raw protocol");
61 MODULE_LICENSE("Dual BSD/GPL");
62 MODULE_AUTHOR("Urs Thuermann <urs.thuermann@volkswagen.de>");
63 MODULE_ALIAS("can-proto-1");
64 
65 #define MASK_ALL 0
66 
67 /*
68  * A raw socket has a list of can_filters attached to it, each receiving
69  * the CAN frames matching that filter.  If the filter list is empty,
70  * no CAN frames will be received by the socket.  The default after
71  * opening the socket, is to have one filter which receives all frames.
72  * The filter list is allocated dynamically with the exception of the
73  * list containing only one item.  This common case is optimized by
74  * storing the single filter in dfilter, to avoid using dynamic memory.
75  */
76 
77 struct raw_sock {
78 	struct sock sk;
79 	int bound;
80 	int ifindex;
81 	struct notifier_block notifier;
82 	int loopback;
83 	int recv_own_msgs;
84 	int fd_frames;
85 	int count;                 /* number of active filters */
86 	struct can_filter dfilter; /* default/single filter */
87 	struct can_filter *filter; /* pointer to filter(s) */
88 	can_err_mask_t err_mask;
89 };
90 
91 /*
92  * Return pointer to store the extra msg flags for raw_recvmsg().
93  * We use the space of one unsigned int beyond the 'struct sockaddr_can'
94  * in skb->cb.
95  */
96 static inline unsigned int *raw_flags(struct sk_buff *skb)
97 {
98 	BUILD_BUG_ON(sizeof(skb->cb) <= (sizeof(struct sockaddr_can) +
99 					 sizeof(unsigned int)));
100 
101 	/* return pointer after struct sockaddr_can */
102 	return (unsigned int *)(&((struct sockaddr_can *)skb->cb)[1]);
103 }
104 
105 static inline struct raw_sock *raw_sk(const struct sock *sk)
106 {
107 	return (struct raw_sock *)sk;
108 }
109 
110 static void raw_rcv(struct sk_buff *oskb, void *data)
111 {
112 	struct sock *sk = (struct sock *)data;
113 	struct raw_sock *ro = raw_sk(sk);
114 	struct sockaddr_can *addr;
115 	struct sk_buff *skb;
116 	unsigned int *pflags;
117 
118 	/* check the received tx sock reference */
119 	if (!ro->recv_own_msgs && oskb->sk == sk)
120 		return;
121 
122 	/* do not pass non-CAN2.0 frames to a legacy socket */
123 	if (!ro->fd_frames && oskb->len != CAN_MTU)
124 		return;
125 
126 	/* clone the given skb to be able to enqueue it into the rcv queue */
127 	skb = skb_clone(oskb, GFP_ATOMIC);
128 	if (!skb)
129 		return;
130 
131 	/*
132 	 *  Put the datagram to the queue so that raw_recvmsg() can
133 	 *  get it from there.  We need to pass the interface index to
134 	 *  raw_recvmsg().  We pass a whole struct sockaddr_can in skb->cb
135 	 *  containing the interface index.
136 	 */
137 
138 	BUILD_BUG_ON(sizeof(skb->cb) < sizeof(struct sockaddr_can));
139 	addr = (struct sockaddr_can *)skb->cb;
140 	memset(addr, 0, sizeof(*addr));
141 	addr->can_family  = AF_CAN;
142 	addr->can_ifindex = skb->dev->ifindex;
143 
144 	/* add CAN specific message flags for raw_recvmsg() */
145 	pflags = raw_flags(skb);
146 	*pflags = 0;
147 	if (oskb->sk)
148 		*pflags |= MSG_DONTROUTE;
149 	if (oskb->sk == sk)
150 		*pflags |= MSG_CONFIRM;
151 
152 	if (sock_queue_rcv_skb(sk, skb) < 0)
153 		kfree_skb(skb);
154 }
155 
156 static int raw_enable_filters(struct net_device *dev, struct sock *sk,
157 			      struct can_filter *filter, int count)
158 {
159 	int err = 0;
160 	int i;
161 
162 	for (i = 0; i < count; i++) {
163 		err = can_rx_register(dev, filter[i].can_id,
164 				      filter[i].can_mask,
165 				      raw_rcv, sk, "raw");
166 		if (err) {
167 			/* clean up successfully registered filters */
168 			while (--i >= 0)
169 				can_rx_unregister(dev, filter[i].can_id,
170 						  filter[i].can_mask,
171 						  raw_rcv, sk);
172 			break;
173 		}
174 	}
175 
176 	return err;
177 }
178 
179 static int raw_enable_errfilter(struct net_device *dev, struct sock *sk,
180 				can_err_mask_t err_mask)
181 {
182 	int err = 0;
183 
184 	if (err_mask)
185 		err = can_rx_register(dev, 0, err_mask | CAN_ERR_FLAG,
186 				      raw_rcv, sk, "raw");
187 
188 	return err;
189 }
190 
191 static void raw_disable_filters(struct net_device *dev, struct sock *sk,
192 			      struct can_filter *filter, int count)
193 {
194 	int i;
195 
196 	for (i = 0; i < count; i++)
197 		can_rx_unregister(dev, filter[i].can_id, filter[i].can_mask,
198 				  raw_rcv, sk);
199 }
200 
201 static inline void raw_disable_errfilter(struct net_device *dev,
202 					 struct sock *sk,
203 					 can_err_mask_t err_mask)
204 
205 {
206 	if (err_mask)
207 		can_rx_unregister(dev, 0, err_mask | CAN_ERR_FLAG,
208 				  raw_rcv, sk);
209 }
210 
211 static inline void raw_disable_allfilters(struct net_device *dev,
212 					  struct sock *sk)
213 {
214 	struct raw_sock *ro = raw_sk(sk);
215 
216 	raw_disable_filters(dev, sk, ro->filter, ro->count);
217 	raw_disable_errfilter(dev, sk, ro->err_mask);
218 }
219 
220 static int raw_enable_allfilters(struct net_device *dev, struct sock *sk)
221 {
222 	struct raw_sock *ro = raw_sk(sk);
223 	int err;
224 
225 	err = raw_enable_filters(dev, sk, ro->filter, ro->count);
226 	if (!err) {
227 		err = raw_enable_errfilter(dev, sk, ro->err_mask);
228 		if (err)
229 			raw_disable_filters(dev, sk, ro->filter, ro->count);
230 	}
231 
232 	return err;
233 }
234 
235 static int raw_notifier(struct notifier_block *nb,
236 			unsigned long msg, void *ptr)
237 {
238 	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
239 	struct raw_sock *ro = container_of(nb, struct raw_sock, notifier);
240 	struct sock *sk = &ro->sk;
241 
242 	if (!net_eq(dev_net(dev), &init_net))
243 		return NOTIFY_DONE;
244 
245 	if (dev->type != ARPHRD_CAN)
246 		return NOTIFY_DONE;
247 
248 	if (ro->ifindex != dev->ifindex)
249 		return NOTIFY_DONE;
250 
251 	switch (msg) {
252 
253 	case NETDEV_UNREGISTER:
254 		lock_sock(sk);
255 		/* remove current filters & unregister */
256 		if (ro->bound)
257 			raw_disable_allfilters(dev, sk);
258 
259 		if (ro->count > 1)
260 			kfree(ro->filter);
261 
262 		ro->ifindex = 0;
263 		ro->bound   = 0;
264 		ro->count   = 0;
265 		release_sock(sk);
266 
267 		sk->sk_err = ENODEV;
268 		if (!sock_flag(sk, SOCK_DEAD))
269 			sk->sk_error_report(sk);
270 		break;
271 
272 	case NETDEV_DOWN:
273 		sk->sk_err = ENETDOWN;
274 		if (!sock_flag(sk, SOCK_DEAD))
275 			sk->sk_error_report(sk);
276 		break;
277 	}
278 
279 	return NOTIFY_DONE;
280 }
281 
282 static int raw_init(struct sock *sk)
283 {
284 	struct raw_sock *ro = raw_sk(sk);
285 
286 	ro->bound            = 0;
287 	ro->ifindex          = 0;
288 
289 	/* set default filter to single entry dfilter */
290 	ro->dfilter.can_id   = 0;
291 	ro->dfilter.can_mask = MASK_ALL;
292 	ro->filter           = &ro->dfilter;
293 	ro->count            = 1;
294 
295 	/* set default loopback behaviour */
296 	ro->loopback         = 1;
297 	ro->recv_own_msgs    = 0;
298 	ro->fd_frames        = 0;
299 
300 	/* set notifier */
301 	ro->notifier.notifier_call = raw_notifier;
302 
303 	register_netdevice_notifier(&ro->notifier);
304 
305 	return 0;
306 }
307 
308 static int raw_release(struct socket *sock)
309 {
310 	struct sock *sk = sock->sk;
311 	struct raw_sock *ro;
312 
313 	if (!sk)
314 		return 0;
315 
316 	ro = raw_sk(sk);
317 
318 	unregister_netdevice_notifier(&ro->notifier);
319 
320 	lock_sock(sk);
321 
322 	/* remove current filters & unregister */
323 	if (ro->bound) {
324 		if (ro->ifindex) {
325 			struct net_device *dev;
326 
327 			dev = dev_get_by_index(&init_net, ro->ifindex);
328 			if (dev) {
329 				raw_disable_allfilters(dev, sk);
330 				dev_put(dev);
331 			}
332 		} else
333 			raw_disable_allfilters(NULL, sk);
334 	}
335 
336 	if (ro->count > 1)
337 		kfree(ro->filter);
338 
339 	ro->ifindex = 0;
340 	ro->bound   = 0;
341 	ro->count   = 0;
342 
343 	sock_orphan(sk);
344 	sock->sk = NULL;
345 
346 	release_sock(sk);
347 	sock_put(sk);
348 
349 	return 0;
350 }
351 
352 static int raw_bind(struct socket *sock, struct sockaddr *uaddr, int len)
353 {
354 	struct sockaddr_can *addr = (struct sockaddr_can *)uaddr;
355 	struct sock *sk = sock->sk;
356 	struct raw_sock *ro = raw_sk(sk);
357 	int ifindex;
358 	int err = 0;
359 	int notify_enetdown = 0;
360 
361 	if (len < sizeof(*addr))
362 		return -EINVAL;
363 
364 	lock_sock(sk);
365 
366 	if (ro->bound && addr->can_ifindex == ro->ifindex)
367 		goto out;
368 
369 	if (addr->can_ifindex) {
370 		struct net_device *dev;
371 
372 		dev = dev_get_by_index(&init_net, addr->can_ifindex);
373 		if (!dev) {
374 			err = -ENODEV;
375 			goto out;
376 		}
377 		if (dev->type != ARPHRD_CAN) {
378 			dev_put(dev);
379 			err = -ENODEV;
380 			goto out;
381 		}
382 		if (!(dev->flags & IFF_UP))
383 			notify_enetdown = 1;
384 
385 		ifindex = dev->ifindex;
386 
387 		/* filters set by default/setsockopt */
388 		err = raw_enable_allfilters(dev, sk);
389 		dev_put(dev);
390 	} else {
391 		ifindex = 0;
392 
393 		/* filters set by default/setsockopt */
394 		err = raw_enable_allfilters(NULL, sk);
395 	}
396 
397 	if (!err) {
398 		if (ro->bound) {
399 			/* unregister old filters */
400 			if (ro->ifindex) {
401 				struct net_device *dev;
402 
403 				dev = dev_get_by_index(&init_net, ro->ifindex);
404 				if (dev) {
405 					raw_disable_allfilters(dev, sk);
406 					dev_put(dev);
407 				}
408 			} else
409 				raw_disable_allfilters(NULL, sk);
410 		}
411 		ro->ifindex = ifindex;
412 		ro->bound = 1;
413 	}
414 
415  out:
416 	release_sock(sk);
417 
418 	if (notify_enetdown) {
419 		sk->sk_err = ENETDOWN;
420 		if (!sock_flag(sk, SOCK_DEAD))
421 			sk->sk_error_report(sk);
422 	}
423 
424 	return err;
425 }
426 
427 static int raw_getname(struct socket *sock, struct sockaddr *uaddr,
428 		       int *len, int peer)
429 {
430 	struct sockaddr_can *addr = (struct sockaddr_can *)uaddr;
431 	struct sock *sk = sock->sk;
432 	struct raw_sock *ro = raw_sk(sk);
433 
434 	if (peer)
435 		return -EOPNOTSUPP;
436 
437 	memset(addr, 0, sizeof(*addr));
438 	addr->can_family  = AF_CAN;
439 	addr->can_ifindex = ro->ifindex;
440 
441 	*len = sizeof(*addr);
442 
443 	return 0;
444 }
445 
446 static int raw_setsockopt(struct socket *sock, int level, int optname,
447 			  char __user *optval, unsigned int optlen)
448 {
449 	struct sock *sk = sock->sk;
450 	struct raw_sock *ro = raw_sk(sk);
451 	struct can_filter *filter = NULL;  /* dyn. alloc'ed filters */
452 	struct can_filter sfilter;         /* single filter */
453 	struct net_device *dev = NULL;
454 	can_err_mask_t err_mask = 0;
455 	int count = 0;
456 	int err = 0;
457 
458 	if (level != SOL_CAN_RAW)
459 		return -EINVAL;
460 
461 	switch (optname) {
462 
463 	case CAN_RAW_FILTER:
464 		if (optlen % sizeof(struct can_filter) != 0)
465 			return -EINVAL;
466 
467 		count = optlen / sizeof(struct can_filter);
468 
469 		if (count > 1) {
470 			/* filter does not fit into dfilter => alloc space */
471 			filter = memdup_user(optval, optlen);
472 			if (IS_ERR(filter))
473 				return PTR_ERR(filter);
474 		} else if (count == 1) {
475 			if (copy_from_user(&sfilter, optval, sizeof(sfilter)))
476 				return -EFAULT;
477 		}
478 
479 		lock_sock(sk);
480 
481 		if (ro->bound && ro->ifindex)
482 			dev = dev_get_by_index(&init_net, ro->ifindex);
483 
484 		if (ro->bound) {
485 			/* (try to) register the new filters */
486 			if (count == 1)
487 				err = raw_enable_filters(dev, sk, &sfilter, 1);
488 			else
489 				err = raw_enable_filters(dev, sk, filter,
490 							 count);
491 			if (err) {
492 				if (count > 1)
493 					kfree(filter);
494 				goto out_fil;
495 			}
496 
497 			/* remove old filter registrations */
498 			raw_disable_filters(dev, sk, ro->filter, ro->count);
499 		}
500 
501 		/* remove old filter space */
502 		if (ro->count > 1)
503 			kfree(ro->filter);
504 
505 		/* link new filters to the socket */
506 		if (count == 1) {
507 			/* copy filter data for single filter */
508 			ro->dfilter = sfilter;
509 			filter = &ro->dfilter;
510 		}
511 		ro->filter = filter;
512 		ro->count  = count;
513 
514  out_fil:
515 		if (dev)
516 			dev_put(dev);
517 
518 		release_sock(sk);
519 
520 		break;
521 
522 	case CAN_RAW_ERR_FILTER:
523 		if (optlen != sizeof(err_mask))
524 			return -EINVAL;
525 
526 		if (copy_from_user(&err_mask, optval, optlen))
527 			return -EFAULT;
528 
529 		err_mask &= CAN_ERR_MASK;
530 
531 		lock_sock(sk);
532 
533 		if (ro->bound && ro->ifindex)
534 			dev = dev_get_by_index(&init_net, ro->ifindex);
535 
536 		/* remove current error mask */
537 		if (ro->bound) {
538 			/* (try to) register the new err_mask */
539 			err = raw_enable_errfilter(dev, sk, err_mask);
540 
541 			if (err)
542 				goto out_err;
543 
544 			/* remove old err_mask registration */
545 			raw_disable_errfilter(dev, sk, ro->err_mask);
546 		}
547 
548 		/* link new err_mask to the socket */
549 		ro->err_mask = err_mask;
550 
551  out_err:
552 		if (dev)
553 			dev_put(dev);
554 
555 		release_sock(sk);
556 
557 		break;
558 
559 	case CAN_RAW_LOOPBACK:
560 		if (optlen != sizeof(ro->loopback))
561 			return -EINVAL;
562 
563 		if (copy_from_user(&ro->loopback, optval, optlen))
564 			return -EFAULT;
565 
566 		break;
567 
568 	case CAN_RAW_RECV_OWN_MSGS:
569 		if (optlen != sizeof(ro->recv_own_msgs))
570 			return -EINVAL;
571 
572 		if (copy_from_user(&ro->recv_own_msgs, optval, optlen))
573 			return -EFAULT;
574 
575 		break;
576 
577 	case CAN_RAW_FD_FRAMES:
578 		if (optlen != sizeof(ro->fd_frames))
579 			return -EINVAL;
580 
581 		if (copy_from_user(&ro->fd_frames, optval, optlen))
582 			return -EFAULT;
583 
584 		break;
585 
586 	default:
587 		return -ENOPROTOOPT;
588 	}
589 	return err;
590 }
591 
592 static int raw_getsockopt(struct socket *sock, int level, int optname,
593 			  char __user *optval, int __user *optlen)
594 {
595 	struct sock *sk = sock->sk;
596 	struct raw_sock *ro = raw_sk(sk);
597 	int len;
598 	void *val;
599 	int err = 0;
600 
601 	if (level != SOL_CAN_RAW)
602 		return -EINVAL;
603 	if (get_user(len, optlen))
604 		return -EFAULT;
605 	if (len < 0)
606 		return -EINVAL;
607 
608 	switch (optname) {
609 
610 	case CAN_RAW_FILTER:
611 		lock_sock(sk);
612 		if (ro->count > 0) {
613 			int fsize = ro->count * sizeof(struct can_filter);
614 			if (len > fsize)
615 				len = fsize;
616 			if (copy_to_user(optval, ro->filter, len))
617 				err = -EFAULT;
618 		} else
619 			len = 0;
620 		release_sock(sk);
621 
622 		if (!err)
623 			err = put_user(len, optlen);
624 		return err;
625 
626 	case CAN_RAW_ERR_FILTER:
627 		if (len > sizeof(can_err_mask_t))
628 			len = sizeof(can_err_mask_t);
629 		val = &ro->err_mask;
630 		break;
631 
632 	case CAN_RAW_LOOPBACK:
633 		if (len > sizeof(int))
634 			len = sizeof(int);
635 		val = &ro->loopback;
636 		break;
637 
638 	case CAN_RAW_RECV_OWN_MSGS:
639 		if (len > sizeof(int))
640 			len = sizeof(int);
641 		val = &ro->recv_own_msgs;
642 		break;
643 
644 	case CAN_RAW_FD_FRAMES:
645 		if (len > sizeof(int))
646 			len = sizeof(int);
647 		val = &ro->fd_frames;
648 		break;
649 
650 	default:
651 		return -ENOPROTOOPT;
652 	}
653 
654 	if (put_user(len, optlen))
655 		return -EFAULT;
656 	if (copy_to_user(optval, val, len))
657 		return -EFAULT;
658 	return 0;
659 }
660 
661 static int raw_sendmsg(struct kiocb *iocb, struct socket *sock,
662 		       struct msghdr *msg, size_t size)
663 {
664 	struct sock *sk = sock->sk;
665 	struct raw_sock *ro = raw_sk(sk);
666 	struct sk_buff *skb;
667 	struct net_device *dev;
668 	int ifindex;
669 	int err;
670 
671 	if (msg->msg_name) {
672 		DECLARE_SOCKADDR(struct sockaddr_can *, addr, msg->msg_name);
673 
674 		if (msg->msg_namelen < sizeof(*addr))
675 			return -EINVAL;
676 
677 		if (addr->can_family != AF_CAN)
678 			return -EINVAL;
679 
680 		ifindex = addr->can_ifindex;
681 	} else
682 		ifindex = ro->ifindex;
683 
684 	if (ro->fd_frames) {
685 		if (unlikely(size != CANFD_MTU && size != CAN_MTU))
686 			return -EINVAL;
687 	} else {
688 		if (unlikely(size != CAN_MTU))
689 			return -EINVAL;
690 	}
691 
692 	dev = dev_get_by_index(&init_net, ifindex);
693 	if (!dev)
694 		return -ENXIO;
695 
696 	skb = sock_alloc_send_skb(sk, size + sizeof(struct can_skb_priv),
697 				  msg->msg_flags & MSG_DONTWAIT, &err);
698 	if (!skb)
699 		goto put_dev;
700 
701 	can_skb_reserve(skb);
702 	can_skb_prv(skb)->ifindex = dev->ifindex;
703 
704 	err = memcpy_from_msg(skb_put(skb, size), msg, size);
705 	if (err < 0)
706 		goto free_skb;
707 
708 	sock_tx_timestamp(sk, &skb_shinfo(skb)->tx_flags);
709 
710 	skb->dev = dev;
711 	skb->sk  = sk;
712 	skb->priority = sk->sk_priority;
713 
714 	err = can_send(skb, ro->loopback);
715 
716 	dev_put(dev);
717 
718 	if (err)
719 		goto send_failed;
720 
721 	return size;
722 
723 free_skb:
724 	kfree_skb(skb);
725 put_dev:
726 	dev_put(dev);
727 send_failed:
728 	return err;
729 }
730 
731 static int raw_recvmsg(struct kiocb *iocb, struct socket *sock,
732 		       struct msghdr *msg, size_t size, int flags)
733 {
734 	struct sock *sk = sock->sk;
735 	struct sk_buff *skb;
736 	int err = 0;
737 	int noblock;
738 
739 	noblock =  flags & MSG_DONTWAIT;
740 	flags   &= ~MSG_DONTWAIT;
741 
742 	skb = skb_recv_datagram(sk, flags, noblock, &err);
743 	if (!skb)
744 		return err;
745 
746 	if (size < skb->len)
747 		msg->msg_flags |= MSG_TRUNC;
748 	else
749 		size = skb->len;
750 
751 	err = memcpy_to_msg(msg, skb->data, size);
752 	if (err < 0) {
753 		skb_free_datagram(sk, skb);
754 		return err;
755 	}
756 
757 	sock_recv_ts_and_drops(msg, sk, skb);
758 
759 	if (msg->msg_name) {
760 		__sockaddr_check_size(sizeof(struct sockaddr_can));
761 		msg->msg_namelen = sizeof(struct sockaddr_can);
762 		memcpy(msg->msg_name, skb->cb, msg->msg_namelen);
763 	}
764 
765 	/* assign the flags that have been recorded in raw_rcv() */
766 	msg->msg_flags |= *(raw_flags(skb));
767 
768 	skb_free_datagram(sk, skb);
769 
770 	return size;
771 }
772 
773 static const struct proto_ops raw_ops = {
774 	.family        = PF_CAN,
775 	.release       = raw_release,
776 	.bind          = raw_bind,
777 	.connect       = sock_no_connect,
778 	.socketpair    = sock_no_socketpair,
779 	.accept        = sock_no_accept,
780 	.getname       = raw_getname,
781 	.poll          = datagram_poll,
782 	.ioctl         = can_ioctl,	/* use can_ioctl() from af_can.c */
783 	.listen        = sock_no_listen,
784 	.shutdown      = sock_no_shutdown,
785 	.setsockopt    = raw_setsockopt,
786 	.getsockopt    = raw_getsockopt,
787 	.sendmsg       = raw_sendmsg,
788 	.recvmsg       = raw_recvmsg,
789 	.mmap          = sock_no_mmap,
790 	.sendpage      = sock_no_sendpage,
791 };
792 
793 static struct proto raw_proto __read_mostly = {
794 	.name       = "CAN_RAW",
795 	.owner      = THIS_MODULE,
796 	.obj_size   = sizeof(struct raw_sock),
797 	.init       = raw_init,
798 };
799 
800 static const struct can_proto raw_can_proto = {
801 	.type       = SOCK_RAW,
802 	.protocol   = CAN_RAW,
803 	.ops        = &raw_ops,
804 	.prot       = &raw_proto,
805 };
806 
807 static __init int raw_module_init(void)
808 {
809 	int err;
810 
811 	pr_info("can: raw protocol (rev " CAN_RAW_VERSION ")\n");
812 
813 	err = can_proto_register(&raw_can_proto);
814 	if (err < 0)
815 		printk(KERN_ERR "can: registration of raw protocol failed\n");
816 
817 	return err;
818 }
819 
820 static __exit void raw_module_exit(void)
821 {
822 	can_proto_unregister(&raw_can_proto);
823 }
824 
825 module_init(raw_module_init);
826 module_exit(raw_module_exit);
827