xref: /linux/net/can/raw.c (revision 3932b9ca55b0be314a36d3e84faff3e823c081f5)
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 static __initconst const char banner[] =
60 	KERN_INFO "can: raw protocol (rev " CAN_RAW_VERSION ")\n";
61 
62 MODULE_DESCRIPTION("PF_CAN raw protocol");
63 MODULE_LICENSE("Dual BSD/GPL");
64 MODULE_AUTHOR("Urs Thuermann <urs.thuermann@volkswagen.de>");
65 MODULE_ALIAS("can-proto-1");
66 
67 #define MASK_ALL 0
68 
69 /*
70  * A raw socket has a list of can_filters attached to it, each receiving
71  * the CAN frames matching that filter.  If the filter list is empty,
72  * no CAN frames will be received by the socket.  The default after
73  * opening the socket, is to have one filter which receives all frames.
74  * The filter list is allocated dynamically with the exception of the
75  * list containing only one item.  This common case is optimized by
76  * storing the single filter in dfilter, to avoid using dynamic memory.
77  */
78 
79 struct raw_sock {
80 	struct sock sk;
81 	int bound;
82 	int ifindex;
83 	struct notifier_block notifier;
84 	int loopback;
85 	int recv_own_msgs;
86 	int fd_frames;
87 	int count;                 /* number of active filters */
88 	struct can_filter dfilter; /* default/single filter */
89 	struct can_filter *filter; /* pointer to filter(s) */
90 	can_err_mask_t err_mask;
91 };
92 
93 /*
94  * Return pointer to store the extra msg flags for raw_recvmsg().
95  * We use the space of one unsigned int beyond the 'struct sockaddr_can'
96  * in skb->cb.
97  */
98 static inline unsigned int *raw_flags(struct sk_buff *skb)
99 {
100 	BUILD_BUG_ON(sizeof(skb->cb) <= (sizeof(struct sockaddr_can) +
101 					 sizeof(unsigned int)));
102 
103 	/* return pointer after struct sockaddr_can */
104 	return (unsigned int *)(&((struct sockaddr_can *)skb->cb)[1]);
105 }
106 
107 static inline struct raw_sock *raw_sk(const struct sock *sk)
108 {
109 	return (struct raw_sock *)sk;
110 }
111 
112 static void raw_rcv(struct sk_buff *oskb, void *data)
113 {
114 	struct sock *sk = (struct sock *)data;
115 	struct raw_sock *ro = raw_sk(sk);
116 	struct sockaddr_can *addr;
117 	struct sk_buff *skb;
118 	unsigned int *pflags;
119 
120 	/* check the received tx sock reference */
121 	if (!ro->recv_own_msgs && oskb->sk == sk)
122 		return;
123 
124 	/* do not pass non-CAN2.0 frames to a legacy socket */
125 	if (!ro->fd_frames && oskb->len != CAN_MTU)
126 		return;
127 
128 	/* clone the given skb to be able to enqueue it into the rcv queue */
129 	skb = skb_clone(oskb, GFP_ATOMIC);
130 	if (!skb)
131 		return;
132 
133 	/*
134 	 *  Put the datagram to the queue so that raw_recvmsg() can
135 	 *  get it from there.  We need to pass the interface index to
136 	 *  raw_recvmsg().  We pass a whole struct sockaddr_can in skb->cb
137 	 *  containing the interface index.
138 	 */
139 
140 	BUILD_BUG_ON(sizeof(skb->cb) < sizeof(struct sockaddr_can));
141 	addr = (struct sockaddr_can *)skb->cb;
142 	memset(addr, 0, sizeof(*addr));
143 	addr->can_family  = AF_CAN;
144 	addr->can_ifindex = skb->dev->ifindex;
145 
146 	/* add CAN specific message flags for raw_recvmsg() */
147 	pflags = raw_flags(skb);
148 	*pflags = 0;
149 	if (oskb->sk)
150 		*pflags |= MSG_DONTROUTE;
151 	if (oskb->sk == sk)
152 		*pflags |= MSG_CONFIRM;
153 
154 	if (sock_queue_rcv_skb(sk, skb) < 0)
155 		kfree_skb(skb);
156 }
157 
158 static int raw_enable_filters(struct net_device *dev, struct sock *sk,
159 			      struct can_filter *filter, int count)
160 {
161 	int err = 0;
162 	int i;
163 
164 	for (i = 0; i < count; i++) {
165 		err = can_rx_register(dev, filter[i].can_id,
166 				      filter[i].can_mask,
167 				      raw_rcv, sk, "raw");
168 		if (err) {
169 			/* clean up successfully registered filters */
170 			while (--i >= 0)
171 				can_rx_unregister(dev, filter[i].can_id,
172 						  filter[i].can_mask,
173 						  raw_rcv, sk);
174 			break;
175 		}
176 	}
177 
178 	return err;
179 }
180 
181 static int raw_enable_errfilter(struct net_device *dev, struct sock *sk,
182 				can_err_mask_t err_mask)
183 {
184 	int err = 0;
185 
186 	if (err_mask)
187 		err = can_rx_register(dev, 0, err_mask | CAN_ERR_FLAG,
188 				      raw_rcv, sk, "raw");
189 
190 	return err;
191 }
192 
193 static void raw_disable_filters(struct net_device *dev, struct sock *sk,
194 			      struct can_filter *filter, int count)
195 {
196 	int i;
197 
198 	for (i = 0; i < count; i++)
199 		can_rx_unregister(dev, filter[i].can_id, filter[i].can_mask,
200 				  raw_rcv, sk);
201 }
202 
203 static inline void raw_disable_errfilter(struct net_device *dev,
204 					 struct sock *sk,
205 					 can_err_mask_t err_mask)
206 
207 {
208 	if (err_mask)
209 		can_rx_unregister(dev, 0, err_mask | CAN_ERR_FLAG,
210 				  raw_rcv, sk);
211 }
212 
213 static inline void raw_disable_allfilters(struct net_device *dev,
214 					  struct sock *sk)
215 {
216 	struct raw_sock *ro = raw_sk(sk);
217 
218 	raw_disable_filters(dev, sk, ro->filter, ro->count);
219 	raw_disable_errfilter(dev, sk, ro->err_mask);
220 }
221 
222 static int raw_enable_allfilters(struct net_device *dev, struct sock *sk)
223 {
224 	struct raw_sock *ro = raw_sk(sk);
225 	int err;
226 
227 	err = raw_enable_filters(dev, sk, ro->filter, ro->count);
228 	if (!err) {
229 		err = raw_enable_errfilter(dev, sk, ro->err_mask);
230 		if (err)
231 			raw_disable_filters(dev, sk, ro->filter, ro->count);
232 	}
233 
234 	return err;
235 }
236 
237 static int raw_notifier(struct notifier_block *nb,
238 			unsigned long msg, void *ptr)
239 {
240 	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
241 	struct raw_sock *ro = container_of(nb, struct raw_sock, notifier);
242 	struct sock *sk = &ro->sk;
243 
244 	if (!net_eq(dev_net(dev), &init_net))
245 		return NOTIFY_DONE;
246 
247 	if (dev->type != ARPHRD_CAN)
248 		return NOTIFY_DONE;
249 
250 	if (ro->ifindex != dev->ifindex)
251 		return NOTIFY_DONE;
252 
253 	switch (msg) {
254 
255 	case NETDEV_UNREGISTER:
256 		lock_sock(sk);
257 		/* remove current filters & unregister */
258 		if (ro->bound)
259 			raw_disable_allfilters(dev, sk);
260 
261 		if (ro->count > 1)
262 			kfree(ro->filter);
263 
264 		ro->ifindex = 0;
265 		ro->bound   = 0;
266 		ro->count   = 0;
267 		release_sock(sk);
268 
269 		sk->sk_err = ENODEV;
270 		if (!sock_flag(sk, SOCK_DEAD))
271 			sk->sk_error_report(sk);
272 		break;
273 
274 	case NETDEV_DOWN:
275 		sk->sk_err = ENETDOWN;
276 		if (!sock_flag(sk, SOCK_DEAD))
277 			sk->sk_error_report(sk);
278 		break;
279 	}
280 
281 	return NOTIFY_DONE;
282 }
283 
284 static int raw_init(struct sock *sk)
285 {
286 	struct raw_sock *ro = raw_sk(sk);
287 
288 	ro->bound            = 0;
289 	ro->ifindex          = 0;
290 
291 	/* set default filter to single entry dfilter */
292 	ro->dfilter.can_id   = 0;
293 	ro->dfilter.can_mask = MASK_ALL;
294 	ro->filter           = &ro->dfilter;
295 	ro->count            = 1;
296 
297 	/* set default loopback behaviour */
298 	ro->loopback         = 1;
299 	ro->recv_own_msgs    = 0;
300 	ro->fd_frames        = 0;
301 
302 	/* set notifier */
303 	ro->notifier.notifier_call = raw_notifier;
304 
305 	register_netdevice_notifier(&ro->notifier);
306 
307 	return 0;
308 }
309 
310 static int raw_release(struct socket *sock)
311 {
312 	struct sock *sk = sock->sk;
313 	struct raw_sock *ro;
314 
315 	if (!sk)
316 		return 0;
317 
318 	ro = raw_sk(sk);
319 
320 	unregister_netdevice_notifier(&ro->notifier);
321 
322 	lock_sock(sk);
323 
324 	/* remove current filters & unregister */
325 	if (ro->bound) {
326 		if (ro->ifindex) {
327 			struct net_device *dev;
328 
329 			dev = dev_get_by_index(&init_net, ro->ifindex);
330 			if (dev) {
331 				raw_disable_allfilters(dev, sk);
332 				dev_put(dev);
333 			}
334 		} else
335 			raw_disable_allfilters(NULL, sk);
336 	}
337 
338 	if (ro->count > 1)
339 		kfree(ro->filter);
340 
341 	ro->ifindex = 0;
342 	ro->bound   = 0;
343 	ro->count   = 0;
344 
345 	sock_orphan(sk);
346 	sock->sk = NULL;
347 
348 	release_sock(sk);
349 	sock_put(sk);
350 
351 	return 0;
352 }
353 
354 static int raw_bind(struct socket *sock, struct sockaddr *uaddr, int len)
355 {
356 	struct sockaddr_can *addr = (struct sockaddr_can *)uaddr;
357 	struct sock *sk = sock->sk;
358 	struct raw_sock *ro = raw_sk(sk);
359 	int ifindex;
360 	int err = 0;
361 	int notify_enetdown = 0;
362 
363 	if (len < sizeof(*addr))
364 		return -EINVAL;
365 
366 	lock_sock(sk);
367 
368 	if (ro->bound && addr->can_ifindex == ro->ifindex)
369 		goto out;
370 
371 	if (addr->can_ifindex) {
372 		struct net_device *dev;
373 
374 		dev = dev_get_by_index(&init_net, addr->can_ifindex);
375 		if (!dev) {
376 			err = -ENODEV;
377 			goto out;
378 		}
379 		if (dev->type != ARPHRD_CAN) {
380 			dev_put(dev);
381 			err = -ENODEV;
382 			goto out;
383 		}
384 		if (!(dev->flags & IFF_UP))
385 			notify_enetdown = 1;
386 
387 		ifindex = dev->ifindex;
388 
389 		/* filters set by default/setsockopt */
390 		err = raw_enable_allfilters(dev, sk);
391 		dev_put(dev);
392 	} else {
393 		ifindex = 0;
394 
395 		/* filters set by default/setsockopt */
396 		err = raw_enable_allfilters(NULL, sk);
397 	}
398 
399 	if (!err) {
400 		if (ro->bound) {
401 			/* unregister old filters */
402 			if (ro->ifindex) {
403 				struct net_device *dev;
404 
405 				dev = dev_get_by_index(&init_net, ro->ifindex);
406 				if (dev) {
407 					raw_disable_allfilters(dev, sk);
408 					dev_put(dev);
409 				}
410 			} else
411 				raw_disable_allfilters(NULL, sk);
412 		}
413 		ro->ifindex = ifindex;
414 		ro->bound = 1;
415 	}
416 
417  out:
418 	release_sock(sk);
419 
420 	if (notify_enetdown) {
421 		sk->sk_err = ENETDOWN;
422 		if (!sock_flag(sk, SOCK_DEAD))
423 			sk->sk_error_report(sk);
424 	}
425 
426 	return err;
427 }
428 
429 static int raw_getname(struct socket *sock, struct sockaddr *uaddr,
430 		       int *len, int peer)
431 {
432 	struct sockaddr_can *addr = (struct sockaddr_can *)uaddr;
433 	struct sock *sk = sock->sk;
434 	struct raw_sock *ro = raw_sk(sk);
435 
436 	if (peer)
437 		return -EOPNOTSUPP;
438 
439 	memset(addr, 0, sizeof(*addr));
440 	addr->can_family  = AF_CAN;
441 	addr->can_ifindex = ro->ifindex;
442 
443 	*len = sizeof(*addr);
444 
445 	return 0;
446 }
447 
448 static int raw_setsockopt(struct socket *sock, int level, int optname,
449 			  char __user *optval, unsigned int optlen)
450 {
451 	struct sock *sk = sock->sk;
452 	struct raw_sock *ro = raw_sk(sk);
453 	struct can_filter *filter = NULL;  /* dyn. alloc'ed filters */
454 	struct can_filter sfilter;         /* single filter */
455 	struct net_device *dev = NULL;
456 	can_err_mask_t err_mask = 0;
457 	int count = 0;
458 	int err = 0;
459 
460 	if (level != SOL_CAN_RAW)
461 		return -EINVAL;
462 
463 	switch (optname) {
464 
465 	case CAN_RAW_FILTER:
466 		if (optlen % sizeof(struct can_filter) != 0)
467 			return -EINVAL;
468 
469 		count = optlen / sizeof(struct can_filter);
470 
471 		if (count > 1) {
472 			/* filter does not fit into dfilter => alloc space */
473 			filter = memdup_user(optval, optlen);
474 			if (IS_ERR(filter))
475 				return PTR_ERR(filter);
476 		} else if (count == 1) {
477 			if (copy_from_user(&sfilter, optval, sizeof(sfilter)))
478 				return -EFAULT;
479 		}
480 
481 		lock_sock(sk);
482 
483 		if (ro->bound && ro->ifindex)
484 			dev = dev_get_by_index(&init_net, ro->ifindex);
485 
486 		if (ro->bound) {
487 			/* (try to) register the new filters */
488 			if (count == 1)
489 				err = raw_enable_filters(dev, sk, &sfilter, 1);
490 			else
491 				err = raw_enable_filters(dev, sk, filter,
492 							 count);
493 			if (err) {
494 				if (count > 1)
495 					kfree(filter);
496 				goto out_fil;
497 			}
498 
499 			/* remove old filter registrations */
500 			raw_disable_filters(dev, sk, ro->filter, ro->count);
501 		}
502 
503 		/* remove old filter space */
504 		if (ro->count > 1)
505 			kfree(ro->filter);
506 
507 		/* link new filters to the socket */
508 		if (count == 1) {
509 			/* copy filter data for single filter */
510 			ro->dfilter = sfilter;
511 			filter = &ro->dfilter;
512 		}
513 		ro->filter = filter;
514 		ro->count  = count;
515 
516  out_fil:
517 		if (dev)
518 			dev_put(dev);
519 
520 		release_sock(sk);
521 
522 		break;
523 
524 	case CAN_RAW_ERR_FILTER:
525 		if (optlen != sizeof(err_mask))
526 			return -EINVAL;
527 
528 		if (copy_from_user(&err_mask, optval, optlen))
529 			return -EFAULT;
530 
531 		err_mask &= CAN_ERR_MASK;
532 
533 		lock_sock(sk);
534 
535 		if (ro->bound && ro->ifindex)
536 			dev = dev_get_by_index(&init_net, ro->ifindex);
537 
538 		/* remove current error mask */
539 		if (ro->bound) {
540 			/* (try to) register the new err_mask */
541 			err = raw_enable_errfilter(dev, sk, err_mask);
542 
543 			if (err)
544 				goto out_err;
545 
546 			/* remove old err_mask registration */
547 			raw_disable_errfilter(dev, sk, ro->err_mask);
548 		}
549 
550 		/* link new err_mask to the socket */
551 		ro->err_mask = err_mask;
552 
553  out_err:
554 		if (dev)
555 			dev_put(dev);
556 
557 		release_sock(sk);
558 
559 		break;
560 
561 	case CAN_RAW_LOOPBACK:
562 		if (optlen != sizeof(ro->loopback))
563 			return -EINVAL;
564 
565 		if (copy_from_user(&ro->loopback, optval, optlen))
566 			return -EFAULT;
567 
568 		break;
569 
570 	case CAN_RAW_RECV_OWN_MSGS:
571 		if (optlen != sizeof(ro->recv_own_msgs))
572 			return -EINVAL;
573 
574 		if (copy_from_user(&ro->recv_own_msgs, optval, optlen))
575 			return -EFAULT;
576 
577 		break;
578 
579 	case CAN_RAW_FD_FRAMES:
580 		if (optlen != sizeof(ro->fd_frames))
581 			return -EINVAL;
582 
583 		if (copy_from_user(&ro->fd_frames, optval, optlen))
584 			return -EFAULT;
585 
586 		break;
587 
588 	default:
589 		return -ENOPROTOOPT;
590 	}
591 	return err;
592 }
593 
594 static int raw_getsockopt(struct socket *sock, int level, int optname,
595 			  char __user *optval, int __user *optlen)
596 {
597 	struct sock *sk = sock->sk;
598 	struct raw_sock *ro = raw_sk(sk);
599 	int len;
600 	void *val;
601 	int err = 0;
602 
603 	if (level != SOL_CAN_RAW)
604 		return -EINVAL;
605 	if (get_user(len, optlen))
606 		return -EFAULT;
607 	if (len < 0)
608 		return -EINVAL;
609 
610 	switch (optname) {
611 
612 	case CAN_RAW_FILTER:
613 		lock_sock(sk);
614 		if (ro->count > 0) {
615 			int fsize = ro->count * sizeof(struct can_filter);
616 			if (len > fsize)
617 				len = fsize;
618 			if (copy_to_user(optval, ro->filter, len))
619 				err = -EFAULT;
620 		} else
621 			len = 0;
622 		release_sock(sk);
623 
624 		if (!err)
625 			err = put_user(len, optlen);
626 		return err;
627 
628 	case CAN_RAW_ERR_FILTER:
629 		if (len > sizeof(can_err_mask_t))
630 			len = sizeof(can_err_mask_t);
631 		val = &ro->err_mask;
632 		break;
633 
634 	case CAN_RAW_LOOPBACK:
635 		if (len > sizeof(int))
636 			len = sizeof(int);
637 		val = &ro->loopback;
638 		break;
639 
640 	case CAN_RAW_RECV_OWN_MSGS:
641 		if (len > sizeof(int))
642 			len = sizeof(int);
643 		val = &ro->recv_own_msgs;
644 		break;
645 
646 	case CAN_RAW_FD_FRAMES:
647 		if (len > sizeof(int))
648 			len = sizeof(int);
649 		val = &ro->fd_frames;
650 		break;
651 
652 	default:
653 		return -ENOPROTOOPT;
654 	}
655 
656 	if (put_user(len, optlen))
657 		return -EFAULT;
658 	if (copy_to_user(optval, val, len))
659 		return -EFAULT;
660 	return 0;
661 }
662 
663 static int raw_sendmsg(struct kiocb *iocb, struct socket *sock,
664 		       struct msghdr *msg, size_t size)
665 {
666 	struct sock *sk = sock->sk;
667 	struct raw_sock *ro = raw_sk(sk);
668 	struct sk_buff *skb;
669 	struct net_device *dev;
670 	int ifindex;
671 	int err;
672 
673 	if (msg->msg_name) {
674 		DECLARE_SOCKADDR(struct sockaddr_can *, addr, msg->msg_name);
675 
676 		if (msg->msg_namelen < sizeof(*addr))
677 			return -EINVAL;
678 
679 		if (addr->can_family != AF_CAN)
680 			return -EINVAL;
681 
682 		ifindex = addr->can_ifindex;
683 	} else
684 		ifindex = ro->ifindex;
685 
686 	if (ro->fd_frames) {
687 		if (unlikely(size != CANFD_MTU && size != CAN_MTU))
688 			return -EINVAL;
689 	} else {
690 		if (unlikely(size != CAN_MTU))
691 			return -EINVAL;
692 	}
693 
694 	dev = dev_get_by_index(&init_net, ifindex);
695 	if (!dev)
696 		return -ENXIO;
697 
698 	skb = sock_alloc_send_skb(sk, size + sizeof(struct can_skb_priv),
699 				  msg->msg_flags & MSG_DONTWAIT, &err);
700 	if (!skb)
701 		goto put_dev;
702 
703 	can_skb_reserve(skb);
704 	can_skb_prv(skb)->ifindex = dev->ifindex;
705 
706 	err = memcpy_fromiovec(skb_put(skb, size), msg->msg_iov, size);
707 	if (err < 0)
708 		goto free_skb;
709 
710 	sock_tx_timestamp(sk, &skb_shinfo(skb)->tx_flags);
711 
712 	skb->dev = dev;
713 	skb->sk  = sk;
714 	skb->priority = sk->sk_priority;
715 
716 	err = can_send(skb, ro->loopback);
717 
718 	dev_put(dev);
719 
720 	if (err)
721 		goto send_failed;
722 
723 	return size;
724 
725 free_skb:
726 	kfree_skb(skb);
727 put_dev:
728 	dev_put(dev);
729 send_failed:
730 	return err;
731 }
732 
733 static int raw_recvmsg(struct kiocb *iocb, struct socket *sock,
734 		       struct msghdr *msg, size_t size, int flags)
735 {
736 	struct sock *sk = sock->sk;
737 	struct sk_buff *skb;
738 	int err = 0;
739 	int noblock;
740 
741 	noblock =  flags & MSG_DONTWAIT;
742 	flags   &= ~MSG_DONTWAIT;
743 
744 	skb = skb_recv_datagram(sk, flags, noblock, &err);
745 	if (!skb)
746 		return err;
747 
748 	if (size < skb->len)
749 		msg->msg_flags |= MSG_TRUNC;
750 	else
751 		size = skb->len;
752 
753 	err = memcpy_toiovec(msg->msg_iov, skb->data, size);
754 	if (err < 0) {
755 		skb_free_datagram(sk, skb);
756 		return err;
757 	}
758 
759 	sock_recv_ts_and_drops(msg, sk, skb);
760 
761 	if (msg->msg_name) {
762 		__sockaddr_check_size(sizeof(struct sockaddr_can));
763 		msg->msg_namelen = sizeof(struct sockaddr_can);
764 		memcpy(msg->msg_name, skb->cb, msg->msg_namelen);
765 	}
766 
767 	/* assign the flags that have been recorded in raw_rcv() */
768 	msg->msg_flags |= *(raw_flags(skb));
769 
770 	skb_free_datagram(sk, skb);
771 
772 	return size;
773 }
774 
775 static const struct proto_ops raw_ops = {
776 	.family        = PF_CAN,
777 	.release       = raw_release,
778 	.bind          = raw_bind,
779 	.connect       = sock_no_connect,
780 	.socketpair    = sock_no_socketpair,
781 	.accept        = sock_no_accept,
782 	.getname       = raw_getname,
783 	.poll          = datagram_poll,
784 	.ioctl         = can_ioctl,	/* use can_ioctl() from af_can.c */
785 	.listen        = sock_no_listen,
786 	.shutdown      = sock_no_shutdown,
787 	.setsockopt    = raw_setsockopt,
788 	.getsockopt    = raw_getsockopt,
789 	.sendmsg       = raw_sendmsg,
790 	.recvmsg       = raw_recvmsg,
791 	.mmap          = sock_no_mmap,
792 	.sendpage      = sock_no_sendpage,
793 };
794 
795 static struct proto raw_proto __read_mostly = {
796 	.name       = "CAN_RAW",
797 	.owner      = THIS_MODULE,
798 	.obj_size   = sizeof(struct raw_sock),
799 	.init       = raw_init,
800 };
801 
802 static const struct can_proto raw_can_proto = {
803 	.type       = SOCK_RAW,
804 	.protocol   = CAN_RAW,
805 	.ops        = &raw_ops,
806 	.prot       = &raw_proto,
807 };
808 
809 static __init int raw_module_init(void)
810 {
811 	int err;
812 
813 	printk(banner);
814 
815 	err = can_proto_register(&raw_can_proto);
816 	if (err < 0)
817 		printk(KERN_ERR "can: registration of raw protocol failed\n");
818 
819 	return err;
820 }
821 
822 static __exit void raw_module_exit(void)
823 {
824 	can_proto_unregister(&raw_can_proto);
825 }
826 
827 module_init(raw_module_init);
828 module_exit(raw_module_exit);
829