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1/*
2 * af_can.c - Protocol family CAN core module
3 * (used by different CAN protocol modules)
4 *
5 * Copyright (c) 2002-2007 Volkswagen Group Electronic Research
6 * All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 3. Neither the name of Volkswagen nor the names of its contributors
17 * may be used to endorse or promote products derived from this software
18 * without specific prior written permission.
19 *
20 * Alternatively, provided that this notice is retained in full, this
21 * software may be distributed under the terms of the GNU General
22 * Public License ("GPL") version 2, in which case the provisions of the
23 * GPL apply INSTEAD OF those given above.
24 *
25 * The provided data structures and external interfaces from this code
26 * are not restricted to be used by modules with a GPL compatible license.
27 *
28 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
29 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
30 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
31 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
32 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
33 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
34 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
35 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
36 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
37 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
38 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
39 * DAMAGE.
40 *
41 * Send feedback to <socketcan-users@lists.berlios.de>
42 *
43 */
44
45#include <linux/module.h>
46#include <linux/init.h>
47#include <linux/kmod.h>
48#include <linux/slab.h>
49#include <linux/list.h>
50#include <linux/spinlock.h>
51#include <linux/rcupdate.h>
52#include <linux/uaccess.h>
53#include <linux/net.h>
54#include <linux/netdevice.h>
55#include <linux/socket.h>
56#include <linux/if_ether.h>
57#include <linux/if_arp.h>
58#include <linux/skbuff.h>
59#include <linux/can.h>
60#include <linux/can/core.h>
61#include <linux/ratelimit.h>
62#include <net/net_namespace.h>
63#include <net/sock.h>
64
65#include "af_can.h"
66
67static __initdata const char banner[] = KERN_INFO
68 "can: controller area network core (" CAN_VERSION_STRING ")\n";
69
70MODULE_DESCRIPTION("Controller Area Network PF_CAN core");
71MODULE_LICENSE("Dual BSD/GPL");
72MODULE_AUTHOR("Urs Thuermann <urs.thuermann@volkswagen.de>, "
73 "Oliver Hartkopp <oliver.hartkopp@volkswagen.de>");
74
75MODULE_ALIAS_NETPROTO(PF_CAN);
76
77static int stats_timer __read_mostly = 1;
78module_param(stats_timer, int, S_IRUGO);
79MODULE_PARM_DESC(stats_timer, "enable timer for statistics (default:on)");
80
81/* receive filters subscribed for 'all' CAN devices */
82struct dev_rcv_lists can_rx_alldev_list;
83static DEFINE_SPINLOCK(can_rcvlists_lock);
84
85static struct kmem_cache *rcv_cache __read_mostly;
86
87/* table of registered CAN protocols */
88static const struct can_proto *proto_tab[CAN_NPROTO] __read_mostly;
89static DEFINE_MUTEX(proto_tab_lock);
90
91struct timer_list can_stattimer; /* timer for statistics update */
92struct s_stats can_stats; /* packet statistics */
93struct s_pstats can_pstats; /* receive list statistics */
94
95/*
96 * af_can socket functions
97 */
98
99int can_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
100{
101 struct sock *sk = sock->sk;
102
103 switch (cmd) {
104
105 case SIOCGSTAMP:
106 return sock_get_timestamp(sk, (struct timeval __user *)arg);
107
108 default:
109 return -ENOIOCTLCMD;
110 }
111}
112EXPORT_SYMBOL(can_ioctl);
113
114static void can_sock_destruct(struct sock *sk)
115{
116 skb_queue_purge(&sk->sk_receive_queue);
117}
118
119static const struct can_proto *can_get_proto(int protocol)
120{
121 const struct can_proto *cp;
122
123 rcu_read_lock();
124 cp = rcu_dereference(proto_tab[protocol]);
125 if (cp && !try_module_get(cp->prot->owner))
126 cp = NULL;
127 rcu_read_unlock();
128
129 return cp;
130}
131
132static inline void can_put_proto(const struct can_proto *cp)
133{
134 module_put(cp->prot->owner);
135}
136
137static int can_create(struct net *net, struct socket *sock, int protocol,
138 int kern)
139{
140 struct sock *sk;
141 const struct can_proto *cp;
142 int err = 0;
143
144 sock->state = SS_UNCONNECTED;
145
146 if (protocol < 0 || protocol >= CAN_NPROTO)
147 return -EINVAL;
148
149 if (!net_eq(net, &init_net))
150 return -EAFNOSUPPORT;
151
152 cp = can_get_proto(protocol);
153
154#ifdef CONFIG_MODULES
155 if (!cp) {
156 /* try to load protocol module if kernel is modular */
157
158 err = request_module("can-proto-%d", protocol);
159
160 /*
161 * In case of error we only print a message but don't
162 * return the error code immediately. Below we will
163 * return -EPROTONOSUPPORT
164 */
165 if (err)
166 printk_ratelimited(KERN_ERR "can: request_module "
167 "(can-proto-%d) failed.\n", protocol);
168
169 cp = can_get_proto(protocol);
170 }
171#endif
172
173 /* check for available protocol and correct usage */
174
175 if (!cp)
176 return -EPROTONOSUPPORT;
177
178 if (cp->type != sock->type) {
179 err = -EPROTOTYPE;
180 goto errout;
181 }
182
183 sock->ops = cp->ops;
184
185 sk = sk_alloc(net, PF_CAN, GFP_KERNEL, cp->prot);
186 if (!sk) {
187 err = -ENOMEM;
188 goto errout;
189 }
190
191 sock_init_data(sock, sk);
192 sk->sk_destruct = can_sock_destruct;
193
194 if (sk->sk_prot->init)
195 err = sk->sk_prot->init(sk);
196
197 if (err) {
198 /* release sk on errors */
199 sock_orphan(sk);
200 sock_put(sk);
201 }
202
203 errout:
204 can_put_proto(cp);
205 return err;
206}
207
208/*
209 * af_can tx path
210 */
211
212/**
213 * can_send - transmit a CAN frame (optional with local loopback)
214 * @skb: pointer to socket buffer with CAN frame in data section
215 * @loop: loopback for listeners on local CAN sockets (recommended default!)
216 *
217 * Due to the loopback this routine must not be called from hardirq context.
218 *
219 * Return:
220 * 0 on success
221 * -ENETDOWN when the selected interface is down
222 * -ENOBUFS on full driver queue (see net_xmit_errno())
223 * -ENOMEM when local loopback failed at calling skb_clone()
224 * -EPERM when trying to send on a non-CAN interface
225 * -EINVAL when the skb->data does not contain a valid CAN frame
226 */
227int can_send(struct sk_buff *skb, int loop)
228{
229 struct sk_buff *newskb = NULL;
230 struct can_frame *cf = (struct can_frame *)skb->data;
231 int err;
232
233 if (skb->len != sizeof(struct can_frame) || cf->can_dlc > 8) {
234 kfree_skb(skb);
235 return -EINVAL;
236 }
237
238 if (skb->dev->type != ARPHRD_CAN) {
239 kfree_skb(skb);
240 return -EPERM;
241 }
242
243 if (!(skb->dev->flags & IFF_UP)) {
244 kfree_skb(skb);
245 return -ENETDOWN;
246 }
247
248 skb->protocol = htons(ETH_P_CAN);
249 skb_reset_network_header(skb);
250 skb_reset_transport_header(skb);
251
252 if (loop) {
253 /* local loopback of sent CAN frames */
254
255 /* indication for the CAN driver: do loopback */
256 skb->pkt_type = PACKET_LOOPBACK;
257
258 /*
259 * The reference to the originating sock may be required
260 * by the receiving socket to check whether the frame is
261 * its own. Example: can_raw sockopt CAN_RAW_RECV_OWN_MSGS
262 * Therefore we have to ensure that skb->sk remains the
263 * reference to the originating sock by restoring skb->sk
264 * after each skb_clone() or skb_orphan() usage.
265 */
266
267 if (!(skb->dev->flags & IFF_ECHO)) {
268 /*
269 * If the interface is not capable to do loopback
270 * itself, we do it here.
271 */
272 newskb = skb_clone(skb, GFP_ATOMIC);
273 if (!newskb) {
274 kfree_skb(skb);
275 return -ENOMEM;
276 }
277
278 newskb->sk = skb->sk;
279 newskb->ip_summed = CHECKSUM_UNNECESSARY;
280 newskb->pkt_type = PACKET_BROADCAST;
281 }
282 } else {
283 /* indication for the CAN driver: no loopback required */
284 skb->pkt_type = PACKET_HOST;
285 }
286
287 /* send to netdevice */
288 err = dev_queue_xmit(skb);
289 if (err > 0)
290 err = net_xmit_errno(err);
291
292 if (err) {
293 kfree_skb(newskb);
294 return err;
295 }
296
297 if (newskb)
298 netif_rx_ni(newskb);
299
300 /* update statistics */
301 can_stats.tx_frames++;
302 can_stats.tx_frames_delta++;
303
304 return 0;
305}
306EXPORT_SYMBOL(can_send);
307
308/*
309 * af_can rx path
310 */
311
312static struct dev_rcv_lists *find_dev_rcv_lists(struct net_device *dev)
313{
314 if (!dev)
315 return &can_rx_alldev_list;
316 else
317 return (struct dev_rcv_lists *)dev->ml_priv;
318}
319
320/**
321 * find_rcv_list - determine optimal filterlist inside device filter struct
322 * @can_id: pointer to CAN identifier of a given can_filter
323 * @mask: pointer to CAN mask of a given can_filter
324 * @d: pointer to the device filter struct
325 *
326 * Description:
327 * Returns the optimal filterlist to reduce the filter handling in the
328 * receive path. This function is called by service functions that need
329 * to register or unregister a can_filter in the filter lists.
330 *
331 * A filter matches in general, when
332 *
333 * <received_can_id> & mask == can_id & mask
334 *
335 * so every bit set in the mask (even CAN_EFF_FLAG, CAN_RTR_FLAG) describe
336 * relevant bits for the filter.
337 *
338 * The filter can be inverted (CAN_INV_FILTER bit set in can_id) or it can
339 * filter for error frames (CAN_ERR_FLAG bit set in mask). For error frames
340 * there is a special filterlist and a special rx path filter handling.
341 *
342 * Return:
343 * Pointer to optimal filterlist for the given can_id/mask pair.
344 * Constistency checked mask.
345 * Reduced can_id to have a preprocessed filter compare value.
346 */
347static struct hlist_head *find_rcv_list(canid_t *can_id, canid_t *mask,
348 struct dev_rcv_lists *d)
349{
350 canid_t inv = *can_id & CAN_INV_FILTER; /* save flag before masking */
351
352 /* filter for error frames in extra filterlist */
353 if (*mask & CAN_ERR_FLAG) {
354 /* clear CAN_ERR_FLAG in filter entry */
355 *mask &= CAN_ERR_MASK;
356 return &d->rx[RX_ERR];
357 }
358
359 /* with cleared CAN_ERR_FLAG we have a simple mask/value filterpair */
360
361#define CAN_EFF_RTR_FLAGS (CAN_EFF_FLAG | CAN_RTR_FLAG)
362
363 /* ensure valid values in can_mask for 'SFF only' frame filtering */
364 if ((*mask & CAN_EFF_FLAG) && !(*can_id & CAN_EFF_FLAG))
365 *mask &= (CAN_SFF_MASK | CAN_EFF_RTR_FLAGS);
366
367 /* reduce condition testing at receive time */
368 *can_id &= *mask;
369
370 /* inverse can_id/can_mask filter */
371 if (inv)
372 return &d->rx[RX_INV];
373
374 /* mask == 0 => no condition testing at receive time */
375 if (!(*mask))
376 return &d->rx[RX_ALL];
377
378 /* extra filterlists for the subscription of a single non-RTR can_id */
379 if (((*mask & CAN_EFF_RTR_FLAGS) == CAN_EFF_RTR_FLAGS) &&
380 !(*can_id & CAN_RTR_FLAG)) {
381
382 if (*can_id & CAN_EFF_FLAG) {
383 if (*mask == (CAN_EFF_MASK | CAN_EFF_RTR_FLAGS)) {
384 /* RFC: a future use-case for hash-tables? */
385 return &d->rx[RX_EFF];
386 }
387 } else {
388 if (*mask == (CAN_SFF_MASK | CAN_EFF_RTR_FLAGS))
389 return &d->rx_sff[*can_id];
390 }
391 }
392
393 /* default: filter via can_id/can_mask */
394 return &d->rx[RX_FIL];
395}
396
397/**
398 * can_rx_register - subscribe CAN frames from a specific interface
399 * @dev: pointer to netdevice (NULL => subcribe from 'all' CAN devices list)
400 * @can_id: CAN identifier (see description)
401 * @mask: CAN mask (see description)
402 * @func: callback function on filter match
403 * @data: returned parameter for callback function
404 * @ident: string for calling module indentification
405 *
406 * Description:
407 * Invokes the callback function with the received sk_buff and the given
408 * parameter 'data' on a matching receive filter. A filter matches, when
409 *
410 * <received_can_id> & mask == can_id & mask
411 *
412 * The filter can be inverted (CAN_INV_FILTER bit set in can_id) or it can
413 * filter for error frames (CAN_ERR_FLAG bit set in mask).
414 *
415 * The provided pointer to the sk_buff is guaranteed to be valid as long as
416 * the callback function is running. The callback function must *not* free
417 * the given sk_buff while processing it's task. When the given sk_buff is
418 * needed after the end of the callback function it must be cloned inside
419 * the callback function with skb_clone().
420 *
421 * Return:
422 * 0 on success
423 * -ENOMEM on missing cache mem to create subscription entry
424 * -ENODEV unknown device
425 */
426int can_rx_register(struct net_device *dev, canid_t can_id, canid_t mask,
427 void (*func)(struct sk_buff *, void *), void *data,
428 char *ident)
429{
430 struct receiver *r;
431 struct hlist_head *rl;
432 struct dev_rcv_lists *d;
433 int err = 0;
434
435 /* insert new receiver (dev,canid,mask) -> (func,data) */
436
437 if (dev && dev->type != ARPHRD_CAN)
438 return -ENODEV;
439
440 r = kmem_cache_alloc(rcv_cache, GFP_KERNEL);
441 if (!r)
442 return -ENOMEM;
443
444 spin_lock(&can_rcvlists_lock);
445
446 d = find_dev_rcv_lists(dev);
447 if (d) {
448 rl = find_rcv_list(&can_id, &mask, d);
449
450 r->can_id = can_id;
451 r->mask = mask;
452 r->matches = 0;
453 r->func = func;
454 r->data = data;
455 r->ident = ident;
456
457 hlist_add_head_rcu(&r->list, rl);
458 d->entries++;
459
460 can_pstats.rcv_entries++;
461 if (can_pstats.rcv_entries_max < can_pstats.rcv_entries)
462 can_pstats.rcv_entries_max = can_pstats.rcv_entries;
463 } else {
464 kmem_cache_free(rcv_cache, r);
465 err = -ENODEV;
466 }
467
468 spin_unlock(&can_rcvlists_lock);
469
470 return err;
471}
472EXPORT_SYMBOL(can_rx_register);
473
474/*
475 * can_rx_delete_receiver - rcu callback for single receiver entry removal
476 */
477static void can_rx_delete_receiver(struct rcu_head *rp)
478{
479 struct receiver *r = container_of(rp, struct receiver, rcu);
480
481 kmem_cache_free(rcv_cache, r);
482}
483
484/**
485 * can_rx_unregister - unsubscribe CAN frames from a specific interface
486 * @dev: pointer to netdevice (NULL => unsubcribe from 'all' CAN devices list)
487 * @can_id: CAN identifier
488 * @mask: CAN mask
489 * @func: callback function on filter match
490 * @data: returned parameter for callback function
491 *
492 * Description:
493 * Removes subscription entry depending on given (subscription) values.
494 */
495void can_rx_unregister(struct net_device *dev, canid_t can_id, canid_t mask,
496 void (*func)(struct sk_buff *, void *), void *data)
497{
498 struct receiver *r = NULL;
499 struct hlist_head *rl;
500 struct hlist_node *next;
501 struct dev_rcv_lists *d;
502
503 if (dev && dev->type != ARPHRD_CAN)
504 return;
505
506 spin_lock(&can_rcvlists_lock);
507
508 d = find_dev_rcv_lists(dev);
509 if (!d) {
510 printk(KERN_ERR "BUG: receive list not found for "
511 "dev %s, id %03X, mask %03X\n",
512 DNAME(dev), can_id, mask);
513 goto out;
514 }
515
516 rl = find_rcv_list(&can_id, &mask, d);
517
518 /*
519 * Search the receiver list for the item to delete. This should
520 * exist, since no receiver may be unregistered that hasn't
521 * been registered before.
522 */
523
524 hlist_for_each_entry_rcu(r, next, rl, list) {
525 if (r->can_id == can_id && r->mask == mask &&
526 r->func == func && r->data == data)
527 break;
528 }
529
530 /*
531 * Check for bugs in CAN protocol implementations:
532 * If no matching list item was found, the list cursor variable next
533 * will be NULL, while r will point to the last item of the list.
534 */
535
536 if (!next) {
537 printk(KERN_ERR "BUG: receive list entry not found for "
538 "dev %s, id %03X, mask %03X\n",
539 DNAME(dev), can_id, mask);
540 r = NULL;
541 goto out;
542 }
543
544 hlist_del_rcu(&r->list);
545 d->entries--;
546
547 if (can_pstats.rcv_entries > 0)
548 can_pstats.rcv_entries--;
549
550 /* remove device structure requested by NETDEV_UNREGISTER */
551 if (d->remove_on_zero_entries && !d->entries) {
552 kfree(d);
553 dev->ml_priv = NULL;
554 }
555
556 out:
557 spin_unlock(&can_rcvlists_lock);
558
559 /* schedule the receiver item for deletion */
560 if (r)
561 call_rcu(&r->rcu, can_rx_delete_receiver);
562}
563EXPORT_SYMBOL(can_rx_unregister);
564
565static inline void deliver(struct sk_buff *skb, struct receiver *r)
566{
567 r->func(skb, r->data);
568 r->matches++;
569}
570
571static int can_rcv_filter(struct dev_rcv_lists *d, struct sk_buff *skb)
572{
573 struct receiver *r;
574 struct hlist_node *n;
575 int matches = 0;
576 struct can_frame *cf = (struct can_frame *)skb->data;
577 canid_t can_id = cf->can_id;
578
579 if (d->entries == 0)
580 return 0;
581
582 if (can_id & CAN_ERR_FLAG) {
583 /* check for error frame entries only */
584 hlist_for_each_entry_rcu(r, n, &d->rx[RX_ERR], list) {
585 if (can_id & r->mask) {
586 deliver(skb, r);
587 matches++;
588 }
589 }
590 return matches;
591 }
592
593 /* check for unfiltered entries */
594 hlist_for_each_entry_rcu(r, n, &d->rx[RX_ALL], list) {
595 deliver(skb, r);
596 matches++;
597 }
598
599 /* check for can_id/mask entries */
600 hlist_for_each_entry_rcu(r, n, &d->rx[RX_FIL], list) {
601 if ((can_id & r->mask) == r->can_id) {
602 deliver(skb, r);
603 matches++;
604 }
605 }
606
607 /* check for inverted can_id/mask entries */
608 hlist_for_each_entry_rcu(r, n, &d->rx[RX_INV], list) {
609 if ((can_id & r->mask) != r->can_id) {
610 deliver(skb, r);
611 matches++;
612 }
613 }
614
615 /* check filterlists for single non-RTR can_ids */
616 if (can_id & CAN_RTR_FLAG)
617 return matches;
618
619 if (can_id & CAN_EFF_FLAG) {
620 hlist_for_each_entry_rcu(r, n, &d->rx[RX_EFF], list) {
621 if (r->can_id == can_id) {
622 deliver(skb, r);
623 matches++;
624 }
625 }
626 } else {
627 can_id &= CAN_SFF_MASK;
628 hlist_for_each_entry_rcu(r, n, &d->rx_sff[can_id], list) {
629 deliver(skb, r);
630 matches++;
631 }
632 }
633
634 return matches;
635}
636
637static int can_rcv(struct sk_buff *skb, struct net_device *dev,
638 struct packet_type *pt, struct net_device *orig_dev)
639{
640 struct dev_rcv_lists *d;
641 struct can_frame *cf = (struct can_frame *)skb->data;
642 int matches;
643
644 if (!net_eq(dev_net(dev), &init_net))
645 goto drop;
646
647 if (WARN_ONCE(dev->type != ARPHRD_CAN ||
648 skb->len != sizeof(struct can_frame) ||
649 cf->can_dlc > 8,
650 "PF_CAN: dropped non conform skbuf: "
651 "dev type %d, len %d, can_dlc %d\n",
652 dev->type, skb->len, cf->can_dlc))
653 goto drop;
654
655 /* update statistics */
656 can_stats.rx_frames++;
657 can_stats.rx_frames_delta++;
658
659 rcu_read_lock();
660
661 /* deliver the packet to sockets listening on all devices */
662 matches = can_rcv_filter(&can_rx_alldev_list, skb);
663
664 /* find receive list for this device */
665 d = find_dev_rcv_lists(dev);
666 if (d)
667 matches += can_rcv_filter(d, skb);
668
669 rcu_read_unlock();
670
671 /* consume the skbuff allocated by the netdevice driver */
672 consume_skb(skb);
673
674 if (matches > 0) {
675 can_stats.matches++;
676 can_stats.matches_delta++;
677 }
678
679 return NET_RX_SUCCESS;
680
681drop:
682 kfree_skb(skb);
683 return NET_RX_DROP;
684}
685
686/*
687 * af_can protocol functions
688 */
689
690/**
691 * can_proto_register - register CAN transport protocol
692 * @cp: pointer to CAN protocol structure
693 *
694 * Return:
695 * 0 on success
696 * -EINVAL invalid (out of range) protocol number
697 * -EBUSY protocol already in use
698 * -ENOBUF if proto_register() fails
699 */
700int can_proto_register(const struct can_proto *cp)
701{
702 int proto = cp->protocol;
703 int err = 0;
704
705 if (proto < 0 || proto >= CAN_NPROTO) {
706 printk(KERN_ERR "can: protocol number %d out of range\n",
707 proto);
708 return -EINVAL;
709 }
710
711 err = proto_register(cp->prot, 0);
712 if (err < 0)
713 return err;
714
715 mutex_lock(&proto_tab_lock);
716
717 if (proto_tab[proto]) {
718 printk(KERN_ERR "can: protocol %d already registered\n",
719 proto);
720 err = -EBUSY;
721 } else
722 rcu_assign_pointer(proto_tab[proto], cp);
723
724 mutex_unlock(&proto_tab_lock);
725
726 if (err < 0)
727 proto_unregister(cp->prot);
728
729 return err;
730}
731EXPORT_SYMBOL(can_proto_register);
732
733/**
734 * can_proto_unregister - unregister CAN transport protocol
735 * @cp: pointer to CAN protocol structure
736 */
737void can_proto_unregister(const struct can_proto *cp)
738{
739 int proto = cp->protocol;
740
741 mutex_lock(&proto_tab_lock);
742 BUG_ON(proto_tab[proto] != cp);
743 rcu_assign_pointer(proto_tab[proto], NULL);
744 mutex_unlock(&proto_tab_lock);
745
746 synchronize_rcu();
747
748 proto_unregister(cp->prot);
749}
750EXPORT_SYMBOL(can_proto_unregister);
751
752/*
753 * af_can notifier to create/remove CAN netdevice specific structs
754 */
755static int can_notifier(struct notifier_block *nb, unsigned long msg,
756 void *data)
757{
758 struct net_device *dev = (struct net_device *)data;
759 struct dev_rcv_lists *d;
760
761 if (!net_eq(dev_net(dev), &init_net))
762 return NOTIFY_DONE;
763
764 if (dev->type != ARPHRD_CAN)
765 return NOTIFY_DONE;
766
767 switch (msg) {
768
769 case NETDEV_REGISTER:
770
771 /* create new dev_rcv_lists for this device */
772 d = kzalloc(sizeof(*d), GFP_KERNEL);
773 if (!d) {
774 printk(KERN_ERR
775 "can: allocation of receive list failed\n");
776 return NOTIFY_DONE;
777 }
778 BUG_ON(dev->ml_priv);
779 dev->ml_priv = d;
780
781 break;
782
783 case NETDEV_UNREGISTER:
784 spin_lock(&can_rcvlists_lock);
785
786 d = dev->ml_priv;
787 if (d) {
788 if (d->entries)
789 d->remove_on_zero_entries = 1;
790 else {
791 kfree(d);
792 dev->ml_priv = NULL;
793 }
794 } else
795 printk(KERN_ERR "can: notifier: receive list not "
796 "found for dev %s\n", dev->name);
797
798 spin_unlock(&can_rcvlists_lock);
799
800 break;
801 }
802
803 return NOTIFY_DONE;
804}
805
806/*
807 * af_can module init/exit functions
808 */
809
810static struct packet_type can_packet __read_mostly = {
811 .type = cpu_to_be16(ETH_P_CAN),
812 .dev = NULL,
813 .func = can_rcv,
814};
815
816static const struct net_proto_family can_family_ops = {
817 .family = PF_CAN,
818 .create = can_create,
819 .owner = THIS_MODULE,
820};
821
822/* notifier block for netdevice event */
823static struct notifier_block can_netdev_notifier __read_mostly = {
824 .notifier_call = can_notifier,
825};
826
827static __init int can_init(void)
828{
829 printk(banner);
830
831 memset(&can_rx_alldev_list, 0, sizeof(can_rx_alldev_list));
832
833 rcv_cache = kmem_cache_create("can_receiver", sizeof(struct receiver),
834 0, 0, NULL);
835 if (!rcv_cache)
836 return -ENOMEM;
837
838 if (stats_timer) {
839 /* the statistics are updated every second (timer triggered) */
840 setup_timer(&can_stattimer, can_stat_update, 0);
841 mod_timer(&can_stattimer, round_jiffies(jiffies + HZ));
842 } else
843 can_stattimer.function = NULL;
844
845 can_init_proc();
846
847 /* protocol register */
848 sock_register(&can_family_ops);
849 register_netdevice_notifier(&can_netdev_notifier);
850 dev_add_pack(&can_packet);
851
852 return 0;
853}
854
855static __exit void can_exit(void)
856{
857 struct net_device *dev;
858
859 if (stats_timer)
860 del_timer_sync(&can_stattimer);
861
862 can_remove_proc();
863
864 /* protocol unregister */
865 dev_remove_pack(&can_packet);
866 unregister_netdevice_notifier(&can_netdev_notifier);
867 sock_unregister(PF_CAN);
868
869 /* remove created dev_rcv_lists from still registered CAN devices */
870 rcu_read_lock();
871 for_each_netdev_rcu(&init_net, dev) {
872 if (dev->type == ARPHRD_CAN && dev->ml_priv){
873
874 struct dev_rcv_lists *d = dev->ml_priv;
875
876 BUG_ON(d->entries);
877 kfree(d);
878 dev->ml_priv = NULL;
879 }
880 }
881 rcu_read_unlock();
882
883 rcu_barrier(); /* Wait for completion of call_rcu()'s */
884
885 kmem_cache_destroy(rcv_cache);
886}
887
888module_init(can_init);
889module_exit(can_exit);
1/*
2 * af_can.c - Protocol family CAN core module
3 * (used by different CAN protocol modules)
4 *
5 * Copyright (c) 2002-2007 Volkswagen Group Electronic Research
6 * All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 3. Neither the name of Volkswagen nor the names of its contributors
17 * may be used to endorse or promote products derived from this software
18 * without specific prior written permission.
19 *
20 * Alternatively, provided that this notice is retained in full, this
21 * software may be distributed under the terms of the GNU General
22 * Public License ("GPL") version 2, in which case the provisions of the
23 * GPL apply INSTEAD OF those given above.
24 *
25 * The provided data structures and external interfaces from this code
26 * are not restricted to be used by modules with a GPL compatible license.
27 *
28 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
29 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
30 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
31 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
32 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
33 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
34 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
35 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
36 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
37 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
38 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
39 * DAMAGE.
40 *
41 */
42
43#include <linux/module.h>
44#include <linux/init.h>
45#include <linux/kmod.h>
46#include <linux/slab.h>
47#include <linux/list.h>
48#include <linux/spinlock.h>
49#include <linux/rcupdate.h>
50#include <linux/uaccess.h>
51#include <linux/net.h>
52#include <linux/netdevice.h>
53#include <linux/socket.h>
54#include <linux/if_ether.h>
55#include <linux/if_arp.h>
56#include <linux/skbuff.h>
57#include <linux/can.h>
58#include <linux/can/core.h>
59#include <linux/ratelimit.h>
60#include <net/net_namespace.h>
61#include <net/sock.h>
62
63#include "af_can.h"
64
65static __initdata const char banner[] = KERN_INFO
66 "can: controller area network core (" CAN_VERSION_STRING ")\n";
67
68MODULE_DESCRIPTION("Controller Area Network PF_CAN core");
69MODULE_LICENSE("Dual BSD/GPL");
70MODULE_AUTHOR("Urs Thuermann <urs.thuermann@volkswagen.de>, "
71 "Oliver Hartkopp <oliver.hartkopp@volkswagen.de>");
72
73MODULE_ALIAS_NETPROTO(PF_CAN);
74
75static int stats_timer __read_mostly = 1;
76module_param(stats_timer, int, S_IRUGO);
77MODULE_PARM_DESC(stats_timer, "enable timer for statistics (default:on)");
78
79/* receive filters subscribed for 'all' CAN devices */
80struct dev_rcv_lists can_rx_alldev_list;
81static DEFINE_SPINLOCK(can_rcvlists_lock);
82
83static struct kmem_cache *rcv_cache __read_mostly;
84
85/* table of registered CAN protocols */
86static const struct can_proto *proto_tab[CAN_NPROTO] __read_mostly;
87static DEFINE_MUTEX(proto_tab_lock);
88
89struct timer_list can_stattimer; /* timer for statistics update */
90struct s_stats can_stats; /* packet statistics */
91struct s_pstats can_pstats; /* receive list statistics */
92
93/*
94 * af_can socket functions
95 */
96
97int can_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
98{
99 struct sock *sk = sock->sk;
100
101 switch (cmd) {
102
103 case SIOCGSTAMP:
104 return sock_get_timestamp(sk, (struct timeval __user *)arg);
105
106 default:
107 return -ENOIOCTLCMD;
108 }
109}
110EXPORT_SYMBOL(can_ioctl);
111
112static void can_sock_destruct(struct sock *sk)
113{
114 skb_queue_purge(&sk->sk_receive_queue);
115}
116
117static const struct can_proto *can_get_proto(int protocol)
118{
119 const struct can_proto *cp;
120
121 rcu_read_lock();
122 cp = rcu_dereference(proto_tab[protocol]);
123 if (cp && !try_module_get(cp->prot->owner))
124 cp = NULL;
125 rcu_read_unlock();
126
127 return cp;
128}
129
130static inline void can_put_proto(const struct can_proto *cp)
131{
132 module_put(cp->prot->owner);
133}
134
135static int can_create(struct net *net, struct socket *sock, int protocol,
136 int kern)
137{
138 struct sock *sk;
139 const struct can_proto *cp;
140 int err = 0;
141
142 sock->state = SS_UNCONNECTED;
143
144 if (protocol < 0 || protocol >= CAN_NPROTO)
145 return -EINVAL;
146
147 if (!net_eq(net, &init_net))
148 return -EAFNOSUPPORT;
149
150 cp = can_get_proto(protocol);
151
152#ifdef CONFIG_MODULES
153 if (!cp) {
154 /* try to load protocol module if kernel is modular */
155
156 err = request_module("can-proto-%d", protocol);
157
158 /*
159 * In case of error we only print a message but don't
160 * return the error code immediately. Below we will
161 * return -EPROTONOSUPPORT
162 */
163 if (err)
164 printk_ratelimited(KERN_ERR "can: request_module "
165 "(can-proto-%d) failed.\n", protocol);
166
167 cp = can_get_proto(protocol);
168 }
169#endif
170
171 /* check for available protocol and correct usage */
172
173 if (!cp)
174 return -EPROTONOSUPPORT;
175
176 if (cp->type != sock->type) {
177 err = -EPROTOTYPE;
178 goto errout;
179 }
180
181 sock->ops = cp->ops;
182
183 sk = sk_alloc(net, PF_CAN, GFP_KERNEL, cp->prot);
184 if (!sk) {
185 err = -ENOMEM;
186 goto errout;
187 }
188
189 sock_init_data(sock, sk);
190 sk->sk_destruct = can_sock_destruct;
191
192 if (sk->sk_prot->init)
193 err = sk->sk_prot->init(sk);
194
195 if (err) {
196 /* release sk on errors */
197 sock_orphan(sk);
198 sock_put(sk);
199 }
200
201 errout:
202 can_put_proto(cp);
203 return err;
204}
205
206/*
207 * af_can tx path
208 */
209
210/**
211 * can_send - transmit a CAN frame (optional with local loopback)
212 * @skb: pointer to socket buffer with CAN frame in data section
213 * @loop: loopback for listeners on local CAN sockets (recommended default!)
214 *
215 * Due to the loopback this routine must not be called from hardirq context.
216 *
217 * Return:
218 * 0 on success
219 * -ENETDOWN when the selected interface is down
220 * -ENOBUFS on full driver queue (see net_xmit_errno())
221 * -ENOMEM when local loopback failed at calling skb_clone()
222 * -EPERM when trying to send on a non-CAN interface
223 * -EINVAL when the skb->data does not contain a valid CAN frame
224 */
225int can_send(struct sk_buff *skb, int loop)
226{
227 struct sk_buff *newskb = NULL;
228 struct can_frame *cf = (struct can_frame *)skb->data;
229 int err;
230
231 if (skb->len != sizeof(struct can_frame) || cf->can_dlc > 8) {
232 kfree_skb(skb);
233 return -EINVAL;
234 }
235
236 if (skb->dev->type != ARPHRD_CAN) {
237 kfree_skb(skb);
238 return -EPERM;
239 }
240
241 if (!(skb->dev->flags & IFF_UP)) {
242 kfree_skb(skb);
243 return -ENETDOWN;
244 }
245
246 skb->protocol = htons(ETH_P_CAN);
247 skb_reset_network_header(skb);
248 skb_reset_transport_header(skb);
249
250 if (loop) {
251 /* local loopback of sent CAN frames */
252
253 /* indication for the CAN driver: do loopback */
254 skb->pkt_type = PACKET_LOOPBACK;
255
256 /*
257 * The reference to the originating sock may be required
258 * by the receiving socket to check whether the frame is
259 * its own. Example: can_raw sockopt CAN_RAW_RECV_OWN_MSGS
260 * Therefore we have to ensure that skb->sk remains the
261 * reference to the originating sock by restoring skb->sk
262 * after each skb_clone() or skb_orphan() usage.
263 */
264
265 if (!(skb->dev->flags & IFF_ECHO)) {
266 /*
267 * If the interface is not capable to do loopback
268 * itself, we do it here.
269 */
270 newskb = skb_clone(skb, GFP_ATOMIC);
271 if (!newskb) {
272 kfree_skb(skb);
273 return -ENOMEM;
274 }
275
276 newskb->sk = skb->sk;
277 newskb->ip_summed = CHECKSUM_UNNECESSARY;
278 newskb->pkt_type = PACKET_BROADCAST;
279 }
280 } else {
281 /* indication for the CAN driver: no loopback required */
282 skb->pkt_type = PACKET_HOST;
283 }
284
285 /* send to netdevice */
286 err = dev_queue_xmit(skb);
287 if (err > 0)
288 err = net_xmit_errno(err);
289
290 if (err) {
291 kfree_skb(newskb);
292 return err;
293 }
294
295 if (newskb)
296 netif_rx_ni(newskb);
297
298 /* update statistics */
299 can_stats.tx_frames++;
300 can_stats.tx_frames_delta++;
301
302 return 0;
303}
304EXPORT_SYMBOL(can_send);
305
306/*
307 * af_can rx path
308 */
309
310static struct dev_rcv_lists *find_dev_rcv_lists(struct net_device *dev)
311{
312 if (!dev)
313 return &can_rx_alldev_list;
314 else
315 return (struct dev_rcv_lists *)dev->ml_priv;
316}
317
318/**
319 * find_rcv_list - determine optimal filterlist inside device filter struct
320 * @can_id: pointer to CAN identifier of a given can_filter
321 * @mask: pointer to CAN mask of a given can_filter
322 * @d: pointer to the device filter struct
323 *
324 * Description:
325 * Returns the optimal filterlist to reduce the filter handling in the
326 * receive path. This function is called by service functions that need
327 * to register or unregister a can_filter in the filter lists.
328 *
329 * A filter matches in general, when
330 *
331 * <received_can_id> & mask == can_id & mask
332 *
333 * so every bit set in the mask (even CAN_EFF_FLAG, CAN_RTR_FLAG) describe
334 * relevant bits for the filter.
335 *
336 * The filter can be inverted (CAN_INV_FILTER bit set in can_id) or it can
337 * filter for error frames (CAN_ERR_FLAG bit set in mask). For error frames
338 * there is a special filterlist and a special rx path filter handling.
339 *
340 * Return:
341 * Pointer to optimal filterlist for the given can_id/mask pair.
342 * Constistency checked mask.
343 * Reduced can_id to have a preprocessed filter compare value.
344 */
345static struct hlist_head *find_rcv_list(canid_t *can_id, canid_t *mask,
346 struct dev_rcv_lists *d)
347{
348 canid_t inv = *can_id & CAN_INV_FILTER; /* save flag before masking */
349
350 /* filter for error frames in extra filterlist */
351 if (*mask & CAN_ERR_FLAG) {
352 /* clear CAN_ERR_FLAG in filter entry */
353 *mask &= CAN_ERR_MASK;
354 return &d->rx[RX_ERR];
355 }
356
357 /* with cleared CAN_ERR_FLAG we have a simple mask/value filterpair */
358
359#define CAN_EFF_RTR_FLAGS (CAN_EFF_FLAG | CAN_RTR_FLAG)
360
361 /* ensure valid values in can_mask for 'SFF only' frame filtering */
362 if ((*mask & CAN_EFF_FLAG) && !(*can_id & CAN_EFF_FLAG))
363 *mask &= (CAN_SFF_MASK | CAN_EFF_RTR_FLAGS);
364
365 /* reduce condition testing at receive time */
366 *can_id &= *mask;
367
368 /* inverse can_id/can_mask filter */
369 if (inv)
370 return &d->rx[RX_INV];
371
372 /* mask == 0 => no condition testing at receive time */
373 if (!(*mask))
374 return &d->rx[RX_ALL];
375
376 /* extra filterlists for the subscription of a single non-RTR can_id */
377 if (((*mask & CAN_EFF_RTR_FLAGS) == CAN_EFF_RTR_FLAGS) &&
378 !(*can_id & CAN_RTR_FLAG)) {
379
380 if (*can_id & CAN_EFF_FLAG) {
381 if (*mask == (CAN_EFF_MASK | CAN_EFF_RTR_FLAGS)) {
382 /* RFC: a future use-case for hash-tables? */
383 return &d->rx[RX_EFF];
384 }
385 } else {
386 if (*mask == (CAN_SFF_MASK | CAN_EFF_RTR_FLAGS))
387 return &d->rx_sff[*can_id];
388 }
389 }
390
391 /* default: filter via can_id/can_mask */
392 return &d->rx[RX_FIL];
393}
394
395/**
396 * can_rx_register - subscribe CAN frames from a specific interface
397 * @dev: pointer to netdevice (NULL => subcribe from 'all' CAN devices list)
398 * @can_id: CAN identifier (see description)
399 * @mask: CAN mask (see description)
400 * @func: callback function on filter match
401 * @data: returned parameter for callback function
402 * @ident: string for calling module indentification
403 *
404 * Description:
405 * Invokes the callback function with the received sk_buff and the given
406 * parameter 'data' on a matching receive filter. A filter matches, when
407 *
408 * <received_can_id> & mask == can_id & mask
409 *
410 * The filter can be inverted (CAN_INV_FILTER bit set in can_id) or it can
411 * filter for error frames (CAN_ERR_FLAG bit set in mask).
412 *
413 * The provided pointer to the sk_buff is guaranteed to be valid as long as
414 * the callback function is running. The callback function must *not* free
415 * the given sk_buff while processing it's task. When the given sk_buff is
416 * needed after the end of the callback function it must be cloned inside
417 * the callback function with skb_clone().
418 *
419 * Return:
420 * 0 on success
421 * -ENOMEM on missing cache mem to create subscription entry
422 * -ENODEV unknown device
423 */
424int can_rx_register(struct net_device *dev, canid_t can_id, canid_t mask,
425 void (*func)(struct sk_buff *, void *), void *data,
426 char *ident)
427{
428 struct receiver *r;
429 struct hlist_head *rl;
430 struct dev_rcv_lists *d;
431 int err = 0;
432
433 /* insert new receiver (dev,canid,mask) -> (func,data) */
434
435 if (dev && dev->type != ARPHRD_CAN)
436 return -ENODEV;
437
438 r = kmem_cache_alloc(rcv_cache, GFP_KERNEL);
439 if (!r)
440 return -ENOMEM;
441
442 spin_lock(&can_rcvlists_lock);
443
444 d = find_dev_rcv_lists(dev);
445 if (d) {
446 rl = find_rcv_list(&can_id, &mask, d);
447
448 r->can_id = can_id;
449 r->mask = mask;
450 r->matches = 0;
451 r->func = func;
452 r->data = data;
453 r->ident = ident;
454
455 hlist_add_head_rcu(&r->list, rl);
456 d->entries++;
457
458 can_pstats.rcv_entries++;
459 if (can_pstats.rcv_entries_max < can_pstats.rcv_entries)
460 can_pstats.rcv_entries_max = can_pstats.rcv_entries;
461 } else {
462 kmem_cache_free(rcv_cache, r);
463 err = -ENODEV;
464 }
465
466 spin_unlock(&can_rcvlists_lock);
467
468 return err;
469}
470EXPORT_SYMBOL(can_rx_register);
471
472/*
473 * can_rx_delete_receiver - rcu callback for single receiver entry removal
474 */
475static void can_rx_delete_receiver(struct rcu_head *rp)
476{
477 struct receiver *r = container_of(rp, struct receiver, rcu);
478
479 kmem_cache_free(rcv_cache, r);
480}
481
482/**
483 * can_rx_unregister - unsubscribe CAN frames from a specific interface
484 * @dev: pointer to netdevice (NULL => unsubcribe from 'all' CAN devices list)
485 * @can_id: CAN identifier
486 * @mask: CAN mask
487 * @func: callback function on filter match
488 * @data: returned parameter for callback function
489 *
490 * Description:
491 * Removes subscription entry depending on given (subscription) values.
492 */
493void can_rx_unregister(struct net_device *dev, canid_t can_id, canid_t mask,
494 void (*func)(struct sk_buff *, void *), void *data)
495{
496 struct receiver *r = NULL;
497 struct hlist_head *rl;
498 struct hlist_node *next;
499 struct dev_rcv_lists *d;
500
501 if (dev && dev->type != ARPHRD_CAN)
502 return;
503
504 spin_lock(&can_rcvlists_lock);
505
506 d = find_dev_rcv_lists(dev);
507 if (!d) {
508 printk(KERN_ERR "BUG: receive list not found for "
509 "dev %s, id %03X, mask %03X\n",
510 DNAME(dev), can_id, mask);
511 goto out;
512 }
513
514 rl = find_rcv_list(&can_id, &mask, d);
515
516 /*
517 * Search the receiver list for the item to delete. This should
518 * exist, since no receiver may be unregistered that hasn't
519 * been registered before.
520 */
521
522 hlist_for_each_entry_rcu(r, next, rl, list) {
523 if (r->can_id == can_id && r->mask == mask &&
524 r->func == func && r->data == data)
525 break;
526 }
527
528 /*
529 * Check for bugs in CAN protocol implementations:
530 * If no matching list item was found, the list cursor variable next
531 * will be NULL, while r will point to the last item of the list.
532 */
533
534 if (!next) {
535 printk(KERN_ERR "BUG: receive list entry not found for "
536 "dev %s, id %03X, mask %03X\n",
537 DNAME(dev), can_id, mask);
538 r = NULL;
539 goto out;
540 }
541
542 hlist_del_rcu(&r->list);
543 d->entries--;
544
545 if (can_pstats.rcv_entries > 0)
546 can_pstats.rcv_entries--;
547
548 /* remove device structure requested by NETDEV_UNREGISTER */
549 if (d->remove_on_zero_entries && !d->entries) {
550 kfree(d);
551 dev->ml_priv = NULL;
552 }
553
554 out:
555 spin_unlock(&can_rcvlists_lock);
556
557 /* schedule the receiver item for deletion */
558 if (r)
559 call_rcu(&r->rcu, can_rx_delete_receiver);
560}
561EXPORT_SYMBOL(can_rx_unregister);
562
563static inline void deliver(struct sk_buff *skb, struct receiver *r)
564{
565 r->func(skb, r->data);
566 r->matches++;
567}
568
569static int can_rcv_filter(struct dev_rcv_lists *d, struct sk_buff *skb)
570{
571 struct receiver *r;
572 struct hlist_node *n;
573 int matches = 0;
574 struct can_frame *cf = (struct can_frame *)skb->data;
575 canid_t can_id = cf->can_id;
576
577 if (d->entries == 0)
578 return 0;
579
580 if (can_id & CAN_ERR_FLAG) {
581 /* check for error frame entries only */
582 hlist_for_each_entry_rcu(r, n, &d->rx[RX_ERR], list) {
583 if (can_id & r->mask) {
584 deliver(skb, r);
585 matches++;
586 }
587 }
588 return matches;
589 }
590
591 /* check for unfiltered entries */
592 hlist_for_each_entry_rcu(r, n, &d->rx[RX_ALL], list) {
593 deliver(skb, r);
594 matches++;
595 }
596
597 /* check for can_id/mask entries */
598 hlist_for_each_entry_rcu(r, n, &d->rx[RX_FIL], list) {
599 if ((can_id & r->mask) == r->can_id) {
600 deliver(skb, r);
601 matches++;
602 }
603 }
604
605 /* check for inverted can_id/mask entries */
606 hlist_for_each_entry_rcu(r, n, &d->rx[RX_INV], list) {
607 if ((can_id & r->mask) != r->can_id) {
608 deliver(skb, r);
609 matches++;
610 }
611 }
612
613 /* check filterlists for single non-RTR can_ids */
614 if (can_id & CAN_RTR_FLAG)
615 return matches;
616
617 if (can_id & CAN_EFF_FLAG) {
618 hlist_for_each_entry_rcu(r, n, &d->rx[RX_EFF], list) {
619 if (r->can_id == can_id) {
620 deliver(skb, r);
621 matches++;
622 }
623 }
624 } else {
625 can_id &= CAN_SFF_MASK;
626 hlist_for_each_entry_rcu(r, n, &d->rx_sff[can_id], list) {
627 deliver(skb, r);
628 matches++;
629 }
630 }
631
632 return matches;
633}
634
635static int can_rcv(struct sk_buff *skb, struct net_device *dev,
636 struct packet_type *pt, struct net_device *orig_dev)
637{
638 struct dev_rcv_lists *d;
639 struct can_frame *cf = (struct can_frame *)skb->data;
640 int matches;
641
642 if (!net_eq(dev_net(dev), &init_net))
643 goto drop;
644
645 if (WARN_ONCE(dev->type != ARPHRD_CAN ||
646 skb->len != sizeof(struct can_frame) ||
647 cf->can_dlc > 8,
648 "PF_CAN: dropped non conform skbuf: "
649 "dev type %d, len %d, can_dlc %d\n",
650 dev->type, skb->len, cf->can_dlc))
651 goto drop;
652
653 /* update statistics */
654 can_stats.rx_frames++;
655 can_stats.rx_frames_delta++;
656
657 rcu_read_lock();
658
659 /* deliver the packet to sockets listening on all devices */
660 matches = can_rcv_filter(&can_rx_alldev_list, skb);
661
662 /* find receive list for this device */
663 d = find_dev_rcv_lists(dev);
664 if (d)
665 matches += can_rcv_filter(d, skb);
666
667 rcu_read_unlock();
668
669 /* consume the skbuff allocated by the netdevice driver */
670 consume_skb(skb);
671
672 if (matches > 0) {
673 can_stats.matches++;
674 can_stats.matches_delta++;
675 }
676
677 return NET_RX_SUCCESS;
678
679drop:
680 kfree_skb(skb);
681 return NET_RX_DROP;
682}
683
684/*
685 * af_can protocol functions
686 */
687
688/**
689 * can_proto_register - register CAN transport protocol
690 * @cp: pointer to CAN protocol structure
691 *
692 * Return:
693 * 0 on success
694 * -EINVAL invalid (out of range) protocol number
695 * -EBUSY protocol already in use
696 * -ENOBUF if proto_register() fails
697 */
698int can_proto_register(const struct can_proto *cp)
699{
700 int proto = cp->protocol;
701 int err = 0;
702
703 if (proto < 0 || proto >= CAN_NPROTO) {
704 printk(KERN_ERR "can: protocol number %d out of range\n",
705 proto);
706 return -EINVAL;
707 }
708
709 err = proto_register(cp->prot, 0);
710 if (err < 0)
711 return err;
712
713 mutex_lock(&proto_tab_lock);
714
715 if (proto_tab[proto]) {
716 printk(KERN_ERR "can: protocol %d already registered\n",
717 proto);
718 err = -EBUSY;
719 } else
720 RCU_INIT_POINTER(proto_tab[proto], cp);
721
722 mutex_unlock(&proto_tab_lock);
723
724 if (err < 0)
725 proto_unregister(cp->prot);
726
727 return err;
728}
729EXPORT_SYMBOL(can_proto_register);
730
731/**
732 * can_proto_unregister - unregister CAN transport protocol
733 * @cp: pointer to CAN protocol structure
734 */
735void can_proto_unregister(const struct can_proto *cp)
736{
737 int proto = cp->protocol;
738
739 mutex_lock(&proto_tab_lock);
740 BUG_ON(proto_tab[proto] != cp);
741 RCU_INIT_POINTER(proto_tab[proto], NULL);
742 mutex_unlock(&proto_tab_lock);
743
744 synchronize_rcu();
745
746 proto_unregister(cp->prot);
747}
748EXPORT_SYMBOL(can_proto_unregister);
749
750/*
751 * af_can notifier to create/remove CAN netdevice specific structs
752 */
753static int can_notifier(struct notifier_block *nb, unsigned long msg,
754 void *data)
755{
756 struct net_device *dev = (struct net_device *)data;
757 struct dev_rcv_lists *d;
758
759 if (!net_eq(dev_net(dev), &init_net))
760 return NOTIFY_DONE;
761
762 if (dev->type != ARPHRD_CAN)
763 return NOTIFY_DONE;
764
765 switch (msg) {
766
767 case NETDEV_REGISTER:
768
769 /* create new dev_rcv_lists for this device */
770 d = kzalloc(sizeof(*d), GFP_KERNEL);
771 if (!d) {
772 printk(KERN_ERR
773 "can: allocation of receive list failed\n");
774 return NOTIFY_DONE;
775 }
776 BUG_ON(dev->ml_priv);
777 dev->ml_priv = d;
778
779 break;
780
781 case NETDEV_UNREGISTER:
782 spin_lock(&can_rcvlists_lock);
783
784 d = dev->ml_priv;
785 if (d) {
786 if (d->entries)
787 d->remove_on_zero_entries = 1;
788 else {
789 kfree(d);
790 dev->ml_priv = NULL;
791 }
792 } else
793 printk(KERN_ERR "can: notifier: receive list not "
794 "found for dev %s\n", dev->name);
795
796 spin_unlock(&can_rcvlists_lock);
797
798 break;
799 }
800
801 return NOTIFY_DONE;
802}
803
804/*
805 * af_can module init/exit functions
806 */
807
808static struct packet_type can_packet __read_mostly = {
809 .type = cpu_to_be16(ETH_P_CAN),
810 .dev = NULL,
811 .func = can_rcv,
812};
813
814static const struct net_proto_family can_family_ops = {
815 .family = PF_CAN,
816 .create = can_create,
817 .owner = THIS_MODULE,
818};
819
820/* notifier block for netdevice event */
821static struct notifier_block can_netdev_notifier __read_mostly = {
822 .notifier_call = can_notifier,
823};
824
825static __init int can_init(void)
826{
827 printk(banner);
828
829 memset(&can_rx_alldev_list, 0, sizeof(can_rx_alldev_list));
830
831 rcv_cache = kmem_cache_create("can_receiver", sizeof(struct receiver),
832 0, 0, NULL);
833 if (!rcv_cache)
834 return -ENOMEM;
835
836 if (stats_timer) {
837 /* the statistics are updated every second (timer triggered) */
838 setup_timer(&can_stattimer, can_stat_update, 0);
839 mod_timer(&can_stattimer, round_jiffies(jiffies + HZ));
840 } else
841 can_stattimer.function = NULL;
842
843 can_init_proc();
844
845 /* protocol register */
846 sock_register(&can_family_ops);
847 register_netdevice_notifier(&can_netdev_notifier);
848 dev_add_pack(&can_packet);
849
850 return 0;
851}
852
853static __exit void can_exit(void)
854{
855 struct net_device *dev;
856
857 if (stats_timer)
858 del_timer_sync(&can_stattimer);
859
860 can_remove_proc();
861
862 /* protocol unregister */
863 dev_remove_pack(&can_packet);
864 unregister_netdevice_notifier(&can_netdev_notifier);
865 sock_unregister(PF_CAN);
866
867 /* remove created dev_rcv_lists from still registered CAN devices */
868 rcu_read_lock();
869 for_each_netdev_rcu(&init_net, dev) {
870 if (dev->type == ARPHRD_CAN && dev->ml_priv){
871
872 struct dev_rcv_lists *d = dev->ml_priv;
873
874 BUG_ON(d->entries);
875 kfree(d);
876 dev->ml_priv = NULL;
877 }
878 }
879 rcu_read_unlock();
880
881 rcu_barrier(); /* Wait for completion of call_rcu()'s */
882
883 kmem_cache_destroy(rcv_cache);
884}
885
886module_init(can_init);
887module_exit(can_exit);