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 <net/net_namespace.h>
62 #include <net/sock.h>
63
64 #include "af_can.h"
65
66 static __initdata const char banner[] = KERN_INFO
67 "can: controller area network core (" CAN_VERSION_STRING ")\n";
68
69 MODULE_DESCRIPTION("Controller Area Network PF_CAN core");
70 MODULE_LICENSE("Dual BSD/GPL");
71 MODULE_AUTHOR("Urs Thuermann <urs.thuermann@volkswagen.de>, "
72 "Oliver Hartkopp <oliver.hartkopp@volkswagen.de>");
73
74 MODULE_ALIAS_NETPROTO(PF_CAN);
75
76 static int stats_timer __read_mostly = 1;
77 module_param(stats_timer, int, S_IRUGO);
78 MODULE_PARM_DESC(stats_timer, "enable timer for statistics (default:on)");
79
80 HLIST_HEAD(can_rx_dev_list);
81 static struct dev_rcv_lists can_rx_alldev_list;
82 static DEFINE_SPINLOCK(can_rcvlists_lock);
83
84 static struct kmem_cache *rcv_cache __read_mostly;
85
86 /* table of registered CAN protocols */
87 static struct can_proto *proto_tab[CAN_NPROTO] __read_mostly;
88 static DEFINE_SPINLOCK(proto_tab_lock);
89
90 struct timer_list can_stattimer; /* timer for statistics update */
91 struct s_stats can_stats; /* packet statistics */
92 struct s_pstats can_pstats; /* receive list statistics */
93
94 /*
95 * af_can socket functions
96 */
97
98 static int can_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
99 {
100 struct sock *sk = sock->sk;
101
102 switch (cmd) {
103
104 case SIOCGSTAMP:
105 return sock_get_timestamp(sk, (struct timeval __user *)arg);
106
107 default:
108 return -ENOIOCTLCMD;
109 }
110 }
111
112 static void can_sock_destruct(struct sock *sk)
113 {
114 skb_queue_purge(&sk->sk_receive_queue);
115 }
116
117 static int can_create(struct net *net, struct socket *sock, int protocol)
118 {
119 struct sock *sk;
120 struct can_proto *cp;
121 int err = 0;
122
123 sock->state = SS_UNCONNECTED;
124
125 if (protocol < 0 || protocol >= CAN_NPROTO)
126 return -EINVAL;
127
128 if (net != &init_net)
129 return -EAFNOSUPPORT;
130
131 #ifdef CONFIG_MODULES
132 /* try to load protocol module kernel is modular */
133 if (!proto_tab[protocol]) {
134 err = request_module("can-proto-%d", protocol);
135
136 /*
137 * In case of error we only print a message but don't
138 * return the error code immediately. Below we will
139 * return -EPROTONOSUPPORT
140 */
141 if (err && printk_ratelimit())
142 printk(KERN_ERR "can: request_module "
143 "(can-proto-%d) failed.\n", protocol);
144 }
145 #endif
146
147 spin_lock(&proto_tab_lock);
148 cp = proto_tab[protocol];
149 if (cp && !try_module_get(cp->prot->owner))
150 cp = NULL;
151 spin_unlock(&proto_tab_lock);
152
153 /* check for available protocol and correct usage */
154
155 if (!cp)
156 return -EPROTONOSUPPORT;
157
158 if (cp->type != sock->type) {
159 err = -EPROTONOSUPPORT;
160 goto errout;
161 }
162
163 if (cp->capability >= 0 && !capable(cp->capability)) {
164 err = -EPERM;
165 goto errout;
166 }
167
168 sock->ops = cp->ops;
169
170 sk = sk_alloc(net, PF_CAN, GFP_KERNEL, cp->prot);
171 if (!sk) {
172 err = -ENOMEM;
173 goto errout;
174 }
175
176 sock_init_data(sock, sk);
177 sk->sk_destruct = can_sock_destruct;
178
179 if (sk->sk_prot->init)
180 err = sk->sk_prot->init(sk);
181
182 if (err) {
183 /* release sk on errors */
184 sock_orphan(sk);
185 sock_put(sk);
186 }
187
188 errout:
189 module_put(cp->prot->owner);
190 return err;
191 }
192
193 /*
194 * af_can tx path
195 */
196
197 /**
198 * can_send - transmit a CAN frame (optional with local loopback)
199 * @skb: pointer to socket buffer with CAN frame in data section
200 * @loop: loopback for listeners on local CAN sockets (recommended default!)
201 *
202 * Due to the loopback this routine must not be called from hardirq context.
203 *
204 * Return:
205 * 0 on success
206 * -ENETDOWN when the selected interface is down
207 * -ENOBUFS on full driver queue (see net_xmit_errno())
208 * -ENOMEM when local loopback failed at calling skb_clone()
209 * -EPERM when trying to send on a non-CAN interface
210 * -EINVAL when the skb->data does not contain a valid CAN frame
211 */
212 int can_send(struct sk_buff *skb, int loop)
213 {
214 struct sk_buff *newskb = NULL;
215 struct can_frame *cf = (struct can_frame *)skb->data;
216 int err;
217
218 if (skb->len != sizeof(struct can_frame) || cf->can_dlc > 8) {
219 kfree_skb(skb);
220 return -EINVAL;
221 }
222
223 if (skb->dev->type != ARPHRD_CAN) {
224 kfree_skb(skb);
225 return -EPERM;
226 }
227
228 if (!(skb->dev->flags & IFF_UP)) {
229 kfree_skb(skb);
230 return -ENETDOWN;
231 }
232
233 skb->protocol = htons(ETH_P_CAN);
234 skb_reset_network_header(skb);
235 skb_reset_transport_header(skb);
236
237 if (loop) {
238 /* local loopback of sent CAN frames */
239
240 /* indication for the CAN driver: do loopback */
241 skb->pkt_type = PACKET_LOOPBACK;
242
243 /*
244 * The reference to the originating sock may be required
245 * by the receiving socket to check whether the frame is
246 * its own. Example: can_raw sockopt CAN_RAW_RECV_OWN_MSGS
247 * Therefore we have to ensure that skb->sk remains the
248 * reference to the originating sock by restoring skb->sk
249 * after each skb_clone() or skb_orphan() usage.
250 */
251
252 if (!(skb->dev->flags & IFF_ECHO)) {
253 /*
254 * If the interface is not capable to do loopback
255 * itself, we do it here.
256 */
257 newskb = skb_clone(skb, GFP_ATOMIC);
258 if (!newskb) {
259 kfree_skb(skb);
260 return -ENOMEM;
261 }
262
263 newskb->sk = skb->sk;
264 newskb->ip_summed = CHECKSUM_UNNECESSARY;
265 newskb->pkt_type = PACKET_BROADCAST;
266 }
267 } else {
268 /* indication for the CAN driver: no loopback required */
269 skb->pkt_type = PACKET_HOST;
270 }
271
272 /* send to netdevice */
273 err = dev_queue_xmit(skb);
274 if (err > 0)
275 err = net_xmit_errno(err);
276
277 if (err) {
278 kfree_skb(newskb);
279 return err;
280 }
281
282 if (newskb)
283 netif_rx_ni(newskb);
284
285 /* update statistics */
286 can_stats.tx_frames++;
287 can_stats.tx_frames_delta++;
288
289 return 0;
290 }
291 EXPORT_SYMBOL(can_send);
292
293 /*
294 * af_can rx path
295 */
296
297 static struct dev_rcv_lists *find_dev_rcv_lists(struct net_device *dev)
298 {
299 struct dev_rcv_lists *d = NULL;
300 struct hlist_node *n;
301
302 /*
303 * find receive list for this device
304 *
305 * The hlist_for_each_entry*() macros curse through the list
306 * using the pointer variable n and set d to the containing
307 * struct in each list iteration. Therefore, after list
308 * iteration, d is unmodified when the list is empty, and it
309 * points to last list element, when the list is non-empty
310 * but no match in the loop body is found. I.e. d is *not*
311 * NULL when no match is found. We can, however, use the
312 * cursor variable n to decide if a match was found.
313 */
314
315 hlist_for_each_entry_rcu(d, n, &can_rx_dev_list, list) {
316 if (d->dev == dev)
317 break;
318 }
319
320 return n ? d : NULL;
321 }
322
323 /**
324 * find_rcv_list - determine optimal filterlist inside device filter struct
325 * @can_id: pointer to CAN identifier of a given can_filter
326 * @mask: pointer to CAN mask of a given can_filter
327 * @d: pointer to the device filter struct
328 *
329 * Description:
330 * Returns the optimal filterlist to reduce the filter handling in the
331 * receive path. This function is called by service functions that need
332 * to register or unregister a can_filter in the filter lists.
333 *
334 * A filter matches in general, when
335 *
336 * <received_can_id> & mask == can_id & mask
337 *
338 * so every bit set in the mask (even CAN_EFF_FLAG, CAN_RTR_FLAG) describe
339 * relevant bits for the filter.
340 *
341 * The filter can be inverted (CAN_INV_FILTER bit set in can_id) or it can
342 * filter for error frames (CAN_ERR_FLAG bit set in mask). For error frames
343 * there is a special filterlist and a special rx path filter handling.
344 *
345 * Return:
346 * Pointer to optimal filterlist for the given can_id/mask pair.
347 * Constistency checked mask.
348 * Reduced can_id to have a preprocessed filter compare value.
349 */
350 static struct hlist_head *find_rcv_list(canid_t *can_id, canid_t *mask,
351 struct dev_rcv_lists *d)
352 {
353 canid_t inv = *can_id & CAN_INV_FILTER; /* save flag before masking */
354
355 /* filter for error frames in extra filterlist */
356 if (*mask & CAN_ERR_FLAG) {
357 /* clear CAN_ERR_FLAG in filter entry */
358 *mask &= CAN_ERR_MASK;
359 return &d->rx[RX_ERR];
360 }
361
362 /* with cleared CAN_ERR_FLAG we have a simple mask/value filterpair */
363
364 #define CAN_EFF_RTR_FLAGS (CAN_EFF_FLAG | CAN_RTR_FLAG)
365
366 /* ensure valid values in can_mask for 'SFF only' frame filtering */
367 if ((*mask & CAN_EFF_FLAG) && !(*can_id & CAN_EFF_FLAG))
368 *mask &= (CAN_SFF_MASK | CAN_EFF_RTR_FLAGS);
369
370 /* reduce condition testing at receive time */
371 *can_id &= *mask;
372
373 /* inverse can_id/can_mask filter */
374 if (inv)
375 return &d->rx[RX_INV];
376
377 /* mask == 0 => no condition testing at receive time */
378 if (!(*mask))
379 return &d->rx[RX_ALL];
380
381 /* extra filterlists for the subscription of a single non-RTR can_id */
382 if (((*mask & CAN_EFF_RTR_FLAGS) == CAN_EFF_RTR_FLAGS)
383 && !(*can_id & CAN_RTR_FLAG)) {
384
385 if (*can_id & CAN_EFF_FLAG) {
386 if (*mask == (CAN_EFF_MASK | CAN_EFF_RTR_FLAGS)) {
387 /* RFC: a future use-case for hash-tables? */
388 return &d->rx[RX_EFF];
389 }
390 } else {
391 if (*mask == (CAN_SFF_MASK | CAN_EFF_RTR_FLAGS))
392 return &d->rx_sff[*can_id];
393 }
394 }
395
396 /* default: filter via can_id/can_mask */
397 return &d->rx[RX_FIL];
398 }
399
400 /**
401 * can_rx_register - subscribe CAN frames from a specific interface
402 * @dev: pointer to netdevice (NULL => subcribe from 'all' CAN devices list)
403 * @can_id: CAN identifier (see description)
404 * @mask: CAN mask (see description)
405 * @func: callback function on filter match
406 * @data: returned parameter for callback function
407 * @ident: string for calling module indentification
408 *
409 * Description:
410 * Invokes the callback function with the received sk_buff and the given
411 * parameter 'data' on a matching receive filter. A filter matches, when
412 *
413 * <received_can_id> & mask == can_id & mask
414 *
415 * The filter can be inverted (CAN_INV_FILTER bit set in can_id) or it can
416 * filter for error frames (CAN_ERR_FLAG bit set in mask).
417 *
418 * The provided pointer to the sk_buff is guaranteed to be valid as long as
419 * the callback function is running. The callback function must *not* free
420 * the given sk_buff while processing it's task. When the given sk_buff is
421 * needed after the end of the callback function it must be cloned inside
422 * the callback function with skb_clone().
423 *
424 * Return:
425 * 0 on success
426 * -ENOMEM on missing cache mem to create subscription entry
427 * -ENODEV unknown device
428 */
429 int can_rx_register(struct net_device *dev, canid_t can_id, canid_t mask,
430 void (*func)(struct sk_buff *, void *), void *data,
431 char *ident)
432 {
433 struct receiver *r;
434 struct hlist_head *rl;
435 struct dev_rcv_lists *d;
436 int err = 0;
437
438 /* insert new receiver (dev,canid,mask) -> (func,data) */
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 }
472 EXPORT_SYMBOL(can_rx_register);
473
474 /*
475 * can_rx_delete_device - rcu callback for dev_rcv_lists structure removal
476 */
477 static void can_rx_delete_device(struct rcu_head *rp)
478 {
479 struct dev_rcv_lists *d = container_of(rp, struct dev_rcv_lists, rcu);
480
481 kfree(d);
482 }
483
484 /*
485 * can_rx_delete_receiver - rcu callback for single receiver entry removal
486 */
487 static void can_rx_delete_receiver(struct rcu_head *rp)
488 {
489 struct receiver *r = container_of(rp, struct receiver, rcu);
490
491 kmem_cache_free(rcv_cache, r);
492 }
493
494 /**
495 * can_rx_unregister - unsubscribe CAN frames from a specific interface
496 * @dev: pointer to netdevice (NULL => unsubcribe from 'all' CAN devices list)
497 * @can_id: CAN identifier
498 * @mask: CAN mask
499 * @func: callback function on filter match
500 * @data: returned parameter for callback function
501 *
502 * Description:
503 * Removes subscription entry depending on given (subscription) values.
504 */
505 void can_rx_unregister(struct net_device *dev, canid_t can_id, canid_t mask,
506 void (*func)(struct sk_buff *, void *), void *data)
507 {
508 struct receiver *r = NULL;
509 struct hlist_head *rl;
510 struct hlist_node *next;
511 struct dev_rcv_lists *d;
512
513 spin_lock(&can_rcvlists_lock);
514
515 d = find_dev_rcv_lists(dev);
516 if (!d) {
517 printk(KERN_ERR "BUG: receive list not found for "
518 "dev %s, id %03X, mask %03X\n",
519 DNAME(dev), can_id, mask);
520 goto out;
521 }
522
523 rl = find_rcv_list(&can_id, &mask, d);
524
525 /*
526 * Search the receiver list for the item to delete. This should
527 * exist, since no receiver may be unregistered that hasn't
528 * been registered before.
529 */
530
531 hlist_for_each_entry_rcu(r, next, rl, list) {
532 if (r->can_id == can_id && r->mask == mask
533 && r->func == func && r->data == data)
534 break;
535 }
536
537 /*
538 * Check for bugs in CAN protocol implementations:
539 * If no matching list item was found, the list cursor variable next
540 * will be NULL, while r will point to the last item of the list.
541 */
542
543 if (!next) {
544 printk(KERN_ERR "BUG: receive list entry not found for "
545 "dev %s, id %03X, mask %03X\n",
546 DNAME(dev), can_id, mask);
547 r = NULL;
548 d = NULL;
549 goto out;
550 }
551
552 hlist_del_rcu(&r->list);
553 d->entries--;
554
555 if (can_pstats.rcv_entries > 0)
556 can_pstats.rcv_entries--;
557
558 /* remove device structure requested by NETDEV_UNREGISTER */
559 if (d->remove_on_zero_entries && !d->entries)
560 hlist_del_rcu(&d->list);
561 else
562 d = NULL;
563
564 out:
565 spin_unlock(&can_rcvlists_lock);
566
567 /* schedule the receiver item for deletion */
568 if (r)
569 call_rcu(&r->rcu, can_rx_delete_receiver);
570
571 /* schedule the device structure for deletion */
572 if (d)
573 call_rcu(&d->rcu, can_rx_delete_device);
574 }
575 EXPORT_SYMBOL(can_rx_unregister);
576
577 static inline void deliver(struct sk_buff *skb, struct receiver *r)
578 {
579 r->func(skb, r->data);
580 r->matches++;
581 }
582
583 static int can_rcv_filter(struct dev_rcv_lists *d, struct sk_buff *skb)
584 {
585 struct receiver *r;
586 struct hlist_node *n;
587 int matches = 0;
588 struct can_frame *cf = (struct can_frame *)skb->data;
589 canid_t can_id = cf->can_id;
590
591 if (d->entries == 0)
592 return 0;
593
594 if (can_id & CAN_ERR_FLAG) {
595 /* check for error frame entries only */
596 hlist_for_each_entry_rcu(r, n, &d->rx[RX_ERR], list) {
597 if (can_id & r->mask) {
598 deliver(skb, r);
599 matches++;
600 }
601 }
602 return matches;
603 }
604
605 /* check for unfiltered entries */
606 hlist_for_each_entry_rcu(r, n, &d->rx[RX_ALL], list) {
607 deliver(skb, r);
608 matches++;
609 }
610
611 /* check for can_id/mask entries */
612 hlist_for_each_entry_rcu(r, n, &d->rx[RX_FIL], list) {
613 if ((can_id & r->mask) == r->can_id) {
614 deliver(skb, r);
615 matches++;
616 }
617 }
618
619 /* check for inverted can_id/mask entries */
620 hlist_for_each_entry_rcu(r, n, &d->rx[RX_INV], list) {
621 if ((can_id & r->mask) != r->can_id) {
622 deliver(skb, r);
623 matches++;
624 }
625 }
626
627 /* check filterlists for single non-RTR can_ids */
628 if (can_id & CAN_RTR_FLAG)
629 return matches;
630
631 if (can_id & CAN_EFF_FLAG) {
632 hlist_for_each_entry_rcu(r, n, &d->rx[RX_EFF], list) {
633 if (r->can_id == can_id) {
634 deliver(skb, r);
635 matches++;
636 }
637 }
638 } else {
639 can_id &= CAN_SFF_MASK;
640 hlist_for_each_entry_rcu(r, n, &d->rx_sff[can_id], list) {
641 deliver(skb, r);
642 matches++;
643 }
644 }
645
646 return matches;
647 }
648
649 static int can_rcv(struct sk_buff *skb, struct net_device *dev,
650 struct packet_type *pt, struct net_device *orig_dev)
651 {
652 struct dev_rcv_lists *d;
653 struct can_frame *cf = (struct can_frame *)skb->data;
654 int matches;
655
656 if (dev->type != ARPHRD_CAN || !net_eq(dev_net(dev), &init_net)) {
657 kfree_skb(skb);
658 return 0;
659 }
660
661 BUG_ON(skb->len != sizeof(struct can_frame) || cf->can_dlc > 8);
662
663 /* update statistics */
664 can_stats.rx_frames++;
665 can_stats.rx_frames_delta++;
666
667 rcu_read_lock();
668
669 /* deliver the packet to sockets listening on all devices */
670 matches = can_rcv_filter(&can_rx_alldev_list, skb);
671
672 /* find receive list for this device */
673 d = find_dev_rcv_lists(dev);
674 if (d)
675 matches += can_rcv_filter(d, skb);
676
677 rcu_read_unlock();
678
679 /* consume the skbuff allocated by the netdevice driver */
680 consume_skb(skb);
681
682 if (matches > 0) {
683 can_stats.matches++;
684 can_stats.matches_delta++;
685 }
686
687 return 0;
688 }
689
690 /*
691 * af_can protocol functions
692 */
693
694 /**
695 * can_proto_register - register CAN transport protocol
696 * @cp: pointer to CAN protocol structure
697 *
698 * Return:
699 * 0 on success
700 * -EINVAL invalid (out of range) protocol number
701 * -EBUSY protocol already in use
702 * -ENOBUF if proto_register() fails
703 */
704 int can_proto_register(struct can_proto *cp)
705 {
706 int proto = cp->protocol;
707 int err = 0;
708
709 if (proto < 0 || proto >= CAN_NPROTO) {
710 printk(KERN_ERR "can: protocol number %d out of range\n",
711 proto);
712 return -EINVAL;
713 }
714
715 err = proto_register(cp->prot, 0);
716 if (err < 0)
717 return err;
718
719 spin_lock(&proto_tab_lock);
720 if (proto_tab[proto]) {
721 printk(KERN_ERR "can: protocol %d already registered\n",
722 proto);
723 err = -EBUSY;
724 } else {
725 proto_tab[proto] = cp;
726
727 /* use generic ioctl function if not defined by module */
728 if (!cp->ops->ioctl)
729 cp->ops->ioctl = can_ioctl;
730 }
731 spin_unlock(&proto_tab_lock);
732
733 if (err < 0)
734 proto_unregister(cp->prot);
735
736 return err;
737 }
738 EXPORT_SYMBOL(can_proto_register);
739
740 /**
741 * can_proto_unregister - unregister CAN transport protocol
742 * @cp: pointer to CAN protocol structure
743 */
744 void can_proto_unregister(struct can_proto *cp)
745 {
746 int proto = cp->protocol;
747
748 spin_lock(&proto_tab_lock);
749 if (!proto_tab[proto]) {
750 printk(KERN_ERR "BUG: can: protocol %d is not registered\n",
751 proto);
752 }
753 proto_tab[proto] = NULL;
754 spin_unlock(&proto_tab_lock);
755
756 proto_unregister(cp->prot);
757 }
758 EXPORT_SYMBOL(can_proto_unregister);
759
760 /*
761 * af_can notifier to create/remove CAN netdevice specific structs
762 */
763 static int can_notifier(struct notifier_block *nb, unsigned long msg,
764 void *data)
765 {
766 struct net_device *dev = (struct net_device *)data;
767 struct dev_rcv_lists *d;
768
769 if (!net_eq(dev_net(dev), &init_net))
770 return NOTIFY_DONE;
771
772 if (dev->type != ARPHRD_CAN)
773 return NOTIFY_DONE;
774
775 switch (msg) {
776
777 case NETDEV_REGISTER:
778
779 /*
780 * create new dev_rcv_lists for this device
781 *
782 * N.B. zeroing the struct is the correct initialization
783 * for the embedded hlist_head structs.
784 * Another list type, e.g. list_head, would require
785 * explicit initialization.
786 */
787
788 d = kzalloc(sizeof(*d), GFP_KERNEL);
789 if (!d) {
790 printk(KERN_ERR
791 "can: allocation of receive list failed\n");
792 return NOTIFY_DONE;
793 }
794 d->dev = dev;
795
796 spin_lock(&can_rcvlists_lock);
797 hlist_add_head_rcu(&d->list, &can_rx_dev_list);
798 spin_unlock(&can_rcvlists_lock);
799
800 break;
801
802 case NETDEV_UNREGISTER:
803 spin_lock(&can_rcvlists_lock);
804
805 d = find_dev_rcv_lists(dev);
806 if (d) {
807 if (d->entries) {
808 d->remove_on_zero_entries = 1;
809 d = NULL;
810 } else
811 hlist_del_rcu(&d->list);
812 } else
813 printk(KERN_ERR "can: notifier: receive list not "
814 "found for dev %s\n", dev->name);
815
816 spin_unlock(&can_rcvlists_lock);
817
818 if (d)
819 call_rcu(&d->rcu, can_rx_delete_device);
820
821 break;
822 }
823
824 return NOTIFY_DONE;
825 }
826
827 /*
828 * af_can module init/exit functions
829 */
830
831 static struct packet_type can_packet __read_mostly = {
832 .type = cpu_to_be16(ETH_P_CAN),
833 .dev = NULL,
834 .func = can_rcv,
835 };
836
837 static struct net_proto_family can_family_ops __read_mostly = {
838 .family = PF_CAN,
839 .create = can_create,
840 .owner = THIS_MODULE,
841 };
842
843 /* notifier block for netdevice event */
844 static struct notifier_block can_netdev_notifier __read_mostly = {
845 .notifier_call = can_notifier,
846 };
847
848 static __init int can_init(void)
849 {
850 printk(banner);
851
852 rcv_cache = kmem_cache_create("can_receiver", sizeof(struct receiver),
853 0, 0, NULL);
854 if (!rcv_cache)
855 return -ENOMEM;
856
857 /*
858 * Insert can_rx_alldev_list for reception on all devices.
859 * This struct is zero initialized which is correct for the
860 * embedded hlist heads, the dev pointer, and the entries counter.
861 */
862
863 spin_lock(&can_rcvlists_lock);
864 hlist_add_head_rcu(&can_rx_alldev_list.list, &can_rx_dev_list);
865 spin_unlock(&can_rcvlists_lock);
866
867 if (stats_timer) {
868 /* the statistics are updated every second (timer triggered) */
869 setup_timer(&can_stattimer, can_stat_update, 0);
870 mod_timer(&can_stattimer, round_jiffies(jiffies + HZ));
871 } else
872 can_stattimer.function = NULL;
873
874 can_init_proc();
875
876 /* protocol register */
877 sock_register(&can_family_ops);
878 register_netdevice_notifier(&can_netdev_notifier);
879 dev_add_pack(&can_packet);
880
881 return 0;
882 }
883
884 static __exit void can_exit(void)
885 {
886 struct dev_rcv_lists *d;
887 struct hlist_node *n, *next;
888
889 if (stats_timer)
890 del_timer(&can_stattimer);
891
892 can_remove_proc();
893
894 /* protocol unregister */
895 dev_remove_pack(&can_packet);
896 unregister_netdevice_notifier(&can_netdev_notifier);
897 sock_unregister(PF_CAN);
898
899 /* remove can_rx_dev_list */
900 spin_lock(&can_rcvlists_lock);
901 hlist_del(&can_rx_alldev_list.list);
902 hlist_for_each_entry_safe(d, n, next, &can_rx_dev_list, list) {
903 hlist_del(&d->list);
904 kfree(d);
905 }
906 spin_unlock(&can_rcvlists_lock);
907
908 rcu_barrier(); /* Wait for completion of call_rcu()'s */
909
910 kmem_cache_destroy(rcv_cache);
911 }
912
913 module_init(can_init);
914 module_exit(can_exit);
915
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