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 /* receive filters subscribed for 'all' CAN devices */
81 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
can_ioctl(struct socket * sock,unsigned int cmd,unsigned long arg)98 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 EXPORT_SYMBOL(can_ioctl);
112
can_sock_destruct(struct sock * sk)113 static void can_sock_destruct(struct sock *sk)
114 {
115 skb_queue_purge(&sk->sk_receive_queue);
116 }
117
can_create(struct net * net,struct socket * sock,int protocol,int kern)118 static int can_create(struct net *net, struct socket *sock, int protocol,
119 int kern)
120 {
121 struct sock *sk;
122 struct can_proto *cp;
123 int err = 0;
124
125 sock->state = SS_UNCONNECTED;
126
127 if (protocol < 0 || protocol >= CAN_NPROTO)
128 return -EINVAL;
129
130 if (!net_eq(net, &init_net))
131 return -EAFNOSUPPORT;
132
133 #ifdef CONFIG_MODULES
134 /* try to load protocol module kernel is modular */
135 if (!proto_tab[protocol]) {
136 err = request_module("can-proto-%d", protocol);
137
138 /*
139 * In case of error we only print a message but don't
140 * return the error code immediately. Below we will
141 * return -EPROTONOSUPPORT
142 */
143 if (err && printk_ratelimit())
144 printk(KERN_ERR "can: request_module "
145 "(can-proto-%d) failed.\n", protocol);
146 }
147 #endif
148
149 spin_lock(&proto_tab_lock);
150 cp = proto_tab[protocol];
151 if (cp && !try_module_get(cp->prot->owner))
152 cp = NULL;
153 spin_unlock(&proto_tab_lock);
154
155 /* check for available protocol and correct usage */
156
157 if (!cp)
158 return -EPROTONOSUPPORT;
159
160 if (cp->type != sock->type) {
161 err = -EPROTONOSUPPORT;
162 goto errout;
163 }
164
165 sock->ops = cp->ops;
166
167 sk = sk_alloc(net, PF_CAN, GFP_KERNEL, cp->prot);
168 if (!sk) {
169 err = -ENOMEM;
170 goto errout;
171 }
172
173 sock_init_data(sock, sk);
174 sk->sk_destruct = can_sock_destruct;
175
176 if (sk->sk_prot->init)
177 err = sk->sk_prot->init(sk);
178
179 if (err) {
180 /* release sk on errors */
181 sock_orphan(sk);
182 sock_put(sk);
183 }
184
185 errout:
186 module_put(cp->prot->owner);
187 return err;
188 }
189
190 /*
191 * af_can tx path
192 */
193
194 /**
195 * can_send - transmit a CAN frame (optional with local loopback)
196 * @skb: pointer to socket buffer with CAN frame in data section
197 * @loop: loopback for listeners on local CAN sockets (recommended default!)
198 *
199 * Due to the loopback this routine must not be called from hardirq context.
200 *
201 * Return:
202 * 0 on success
203 * -ENETDOWN when the selected interface is down
204 * -ENOBUFS on full driver queue (see net_xmit_errno())
205 * -ENOMEM when local loopback failed at calling skb_clone()
206 * -EPERM when trying to send on a non-CAN interface
207 * -EINVAL when the skb->data does not contain a valid CAN frame
208 */
can_send(struct sk_buff * skb,int loop)209 int can_send(struct sk_buff *skb, int loop)
210 {
211 struct sk_buff *newskb = NULL;
212 struct can_frame *cf = (struct can_frame *)skb->data;
213 int err;
214
215 if (skb->len != sizeof(struct can_frame) || cf->can_dlc > 8) {
216 kfree_skb(skb);
217 return -EINVAL;
218 }
219
220 if (skb->dev->type != ARPHRD_CAN) {
221 kfree_skb(skb);
222 return -EPERM;
223 }
224
225 if (!(skb->dev->flags & IFF_UP)) {
226 kfree_skb(skb);
227 return -ENETDOWN;
228 }
229
230 skb->protocol = htons(ETH_P_CAN);
231 skb_reset_network_header(skb);
232 skb_reset_transport_header(skb);
233
234 if (loop) {
235 /* local loopback of sent CAN frames */
236
237 /* indication for the CAN driver: do loopback */
238 skb->pkt_type = PACKET_LOOPBACK;
239
240 /*
241 * The reference to the originating sock may be required
242 * by the receiving socket to check whether the frame is
243 * its own. Example: can_raw sockopt CAN_RAW_RECV_OWN_MSGS
244 * Therefore we have to ensure that skb->sk remains the
245 * reference to the originating sock by restoring skb->sk
246 * after each skb_clone() or skb_orphan() usage.
247 */
248
249 if (!(skb->dev->flags & IFF_ECHO)) {
250 /*
251 * If the interface is not capable to do loopback
252 * itself, we do it here.
253 */
254 newskb = skb_clone(skb, GFP_ATOMIC);
255 if (!newskb) {
256 kfree_skb(skb);
257 return -ENOMEM;
258 }
259
260 newskb->sk = skb->sk;
261 newskb->ip_summed = CHECKSUM_UNNECESSARY;
262 newskb->pkt_type = PACKET_BROADCAST;
263 }
264 } else {
265 /* indication for the CAN driver: no loopback required */
266 skb->pkt_type = PACKET_HOST;
267 }
268
269 /* send to netdevice */
270 err = dev_queue_xmit(skb);
271 if (err > 0)
272 err = net_xmit_errno(err);
273
274 if (err) {
275 kfree_skb(newskb);
276 return err;
277 }
278
279 if (newskb)
280 netif_rx_ni(newskb);
281
282 /* update statistics */
283 can_stats.tx_frames++;
284 can_stats.tx_frames_delta++;
285
286 return 0;
287 }
288 EXPORT_SYMBOL(can_send);
289
290 /*
291 * af_can rx path
292 */
293
find_dev_rcv_lists(struct net_device * dev)294 static struct dev_rcv_lists *find_dev_rcv_lists(struct net_device *dev)
295 {
296 if (!dev)
297 return &can_rx_alldev_list;
298 else
299 return (struct dev_rcv_lists *)dev->ml_priv;
300 }
301
302 /**
303 * find_rcv_list - determine optimal filterlist inside device filter struct
304 * @can_id: pointer to CAN identifier of a given can_filter
305 * @mask: pointer to CAN mask of a given can_filter
306 * @d: pointer to the device filter struct
307 *
308 * Description:
309 * Returns the optimal filterlist to reduce the filter handling in the
310 * receive path. This function is called by service functions that need
311 * to register or unregister a can_filter in the filter lists.
312 *
313 * A filter matches in general, when
314 *
315 * <received_can_id> & mask == can_id & mask
316 *
317 * so every bit set in the mask (even CAN_EFF_FLAG, CAN_RTR_FLAG) describe
318 * relevant bits for the filter.
319 *
320 * The filter can be inverted (CAN_INV_FILTER bit set in can_id) or it can
321 * filter for error frames (CAN_ERR_FLAG bit set in mask). For error frames
322 * there is a special filterlist and a special rx path filter handling.
323 *
324 * Return:
325 * Pointer to optimal filterlist for the given can_id/mask pair.
326 * Constistency checked mask.
327 * Reduced can_id to have a preprocessed filter compare value.
328 */
find_rcv_list(canid_t * can_id,canid_t * mask,struct dev_rcv_lists * d)329 static struct hlist_head *find_rcv_list(canid_t *can_id, canid_t *mask,
330 struct dev_rcv_lists *d)
331 {
332 canid_t inv = *can_id & CAN_INV_FILTER; /* save flag before masking */
333
334 /* filter for error frames in extra filterlist */
335 if (*mask & CAN_ERR_FLAG) {
336 /* clear CAN_ERR_FLAG in filter entry */
337 *mask &= CAN_ERR_MASK;
338 return &d->rx[RX_ERR];
339 }
340
341 /* with cleared CAN_ERR_FLAG we have a simple mask/value filterpair */
342
343 #define CAN_EFF_RTR_FLAGS (CAN_EFF_FLAG | CAN_RTR_FLAG)
344
345 /* ensure valid values in can_mask for 'SFF only' frame filtering */
346 if ((*mask & CAN_EFF_FLAG) && !(*can_id & CAN_EFF_FLAG))
347 *mask &= (CAN_SFF_MASK | CAN_EFF_RTR_FLAGS);
348
349 /* reduce condition testing at receive time */
350 *can_id &= *mask;
351
352 /* inverse can_id/can_mask filter */
353 if (inv)
354 return &d->rx[RX_INV];
355
356 /* mask == 0 => no condition testing at receive time */
357 if (!(*mask))
358 return &d->rx[RX_ALL];
359
360 /* extra filterlists for the subscription of a single non-RTR can_id */
361 if (((*mask & CAN_EFF_RTR_FLAGS) == CAN_EFF_RTR_FLAGS) &&
362 !(*can_id & CAN_RTR_FLAG)) {
363
364 if (*can_id & CAN_EFF_FLAG) {
365 if (*mask == (CAN_EFF_MASK | CAN_EFF_RTR_FLAGS)) {
366 /* RFC: a future use-case for hash-tables? */
367 return &d->rx[RX_EFF];
368 }
369 } else {
370 if (*mask == (CAN_SFF_MASK | CAN_EFF_RTR_FLAGS))
371 return &d->rx_sff[*can_id];
372 }
373 }
374
375 /* default: filter via can_id/can_mask */
376 return &d->rx[RX_FIL];
377 }
378
379 /**
380 * can_rx_register - subscribe CAN frames from a specific interface
381 * @dev: pointer to netdevice (NULL => subcribe from 'all' CAN devices list)
382 * @can_id: CAN identifier (see description)
383 * @mask: CAN mask (see description)
384 * @func: callback function on filter match
385 * @data: returned parameter for callback function
386 * @ident: string for calling module indentification
387 *
388 * Description:
389 * Invokes the callback function with the received sk_buff and the given
390 * parameter 'data' on a matching receive filter. A filter matches, when
391 *
392 * <received_can_id> & mask == can_id & mask
393 *
394 * The filter can be inverted (CAN_INV_FILTER bit set in can_id) or it can
395 * filter for error frames (CAN_ERR_FLAG bit set in mask).
396 *
397 * The provided pointer to the sk_buff is guaranteed to be valid as long as
398 * the callback function is running. The callback function must *not* free
399 * the given sk_buff while processing it's task. When the given sk_buff is
400 * needed after the end of the callback function it must be cloned inside
401 * the callback function with skb_clone().
402 *
403 * Return:
404 * 0 on success
405 * -ENOMEM on missing cache mem to create subscription entry
406 * -ENODEV unknown device
407 */
can_rx_register(struct net_device * dev,canid_t can_id,canid_t mask,void (* func)(struct sk_buff *,void *),void * data,char * ident)408 int can_rx_register(struct net_device *dev, canid_t can_id, canid_t mask,
409 void (*func)(struct sk_buff *, void *), void *data,
410 char *ident)
411 {
412 struct receiver *r;
413 struct hlist_head *rl;
414 struct dev_rcv_lists *d;
415 int err = 0;
416
417 /* insert new receiver (dev,canid,mask) -> (func,data) */
418
419 if (dev && dev->type != ARPHRD_CAN)
420 return -ENODEV;
421
422 r = kmem_cache_alloc(rcv_cache, GFP_KERNEL);
423 if (!r)
424 return -ENOMEM;
425
426 spin_lock(&can_rcvlists_lock);
427
428 d = find_dev_rcv_lists(dev);
429 if (d) {
430 rl = find_rcv_list(&can_id, &mask, d);
431
432 r->can_id = can_id;
433 r->mask = mask;
434 r->matches = 0;
435 r->func = func;
436 r->data = data;
437 r->ident = ident;
438
439 hlist_add_head_rcu(&r->list, rl);
440 d->entries++;
441
442 can_pstats.rcv_entries++;
443 if (can_pstats.rcv_entries_max < can_pstats.rcv_entries)
444 can_pstats.rcv_entries_max = can_pstats.rcv_entries;
445 } else {
446 kmem_cache_free(rcv_cache, r);
447 err = -ENODEV;
448 }
449
450 spin_unlock(&can_rcvlists_lock);
451
452 return err;
453 }
454 EXPORT_SYMBOL(can_rx_register);
455
456 /*
457 * can_rx_delete_receiver - rcu callback for single receiver entry removal
458 */
can_rx_delete_receiver(struct rcu_head * rp)459 static void can_rx_delete_receiver(struct rcu_head *rp)
460 {
461 struct receiver *r = container_of(rp, struct receiver, rcu);
462
463 kmem_cache_free(rcv_cache, r);
464 }
465
466 /**
467 * can_rx_unregister - unsubscribe CAN frames from a specific interface
468 * @dev: pointer to netdevice (NULL => unsubcribe from 'all' CAN devices list)
469 * @can_id: CAN identifier
470 * @mask: CAN mask
471 * @func: callback function on filter match
472 * @data: returned parameter for callback function
473 *
474 * Description:
475 * Removes subscription entry depending on given (subscription) values.
476 */
can_rx_unregister(struct net_device * dev,canid_t can_id,canid_t mask,void (* func)(struct sk_buff *,void *),void * data)477 void can_rx_unregister(struct net_device *dev, canid_t can_id, canid_t mask,
478 void (*func)(struct sk_buff *, void *), void *data)
479 {
480 struct receiver *r = NULL;
481 struct hlist_head *rl;
482 struct hlist_node *next;
483 struct dev_rcv_lists *d;
484
485 if (dev && dev->type != ARPHRD_CAN)
486 return;
487
488 spin_lock(&can_rcvlists_lock);
489
490 d = find_dev_rcv_lists(dev);
491 if (!d) {
492 printk(KERN_ERR "BUG: receive list not found for "
493 "dev %s, id %03X, mask %03X\n",
494 DNAME(dev), can_id, mask);
495 goto out;
496 }
497
498 rl = find_rcv_list(&can_id, &mask, d);
499
500 /*
501 * Search the receiver list for the item to delete. This should
502 * exist, since no receiver may be unregistered that hasn't
503 * been registered before.
504 */
505
506 hlist_for_each_entry_rcu(r, next, rl, list) {
507 if (r->can_id == can_id && r->mask == mask &&
508 r->func == func && r->data == data)
509 break;
510 }
511
512 /*
513 * Check for bugs in CAN protocol implementations:
514 * If no matching list item was found, the list cursor variable next
515 * will be NULL, while r will point to the last item of the list.
516 */
517
518 if (!next) {
519 printk(KERN_ERR "BUG: receive list entry not found for "
520 "dev %s, id %03X, mask %03X\n",
521 DNAME(dev), can_id, mask);
522 r = NULL;
523 goto out;
524 }
525
526 hlist_del_rcu(&r->list);
527 d->entries--;
528
529 if (can_pstats.rcv_entries > 0)
530 can_pstats.rcv_entries--;
531
532 /* remove device structure requested by NETDEV_UNREGISTER */
533 if (d->remove_on_zero_entries && !d->entries) {
534 kfree(d);
535 dev->ml_priv = NULL;
536 }
537
538 out:
539 spin_unlock(&can_rcvlists_lock);
540
541 /* schedule the receiver item for deletion */
542 if (r)
543 call_rcu(&r->rcu, can_rx_delete_receiver);
544 }
545 EXPORT_SYMBOL(can_rx_unregister);
546
deliver(struct sk_buff * skb,struct receiver * r)547 static inline void deliver(struct sk_buff *skb, struct receiver *r)
548 {
549 r->func(skb, r->data);
550 r->matches++;
551 }
552
can_rcv_filter(struct dev_rcv_lists * d,struct sk_buff * skb)553 static int can_rcv_filter(struct dev_rcv_lists *d, struct sk_buff *skb)
554 {
555 struct receiver *r;
556 struct hlist_node *n;
557 int matches = 0;
558 struct can_frame *cf = (struct can_frame *)skb->data;
559 canid_t can_id = cf->can_id;
560
561 if (d->entries == 0)
562 return 0;
563
564 if (can_id & CAN_ERR_FLAG) {
565 /* check for error frame entries only */
566 hlist_for_each_entry_rcu(r, n, &d->rx[RX_ERR], list) {
567 if (can_id & r->mask) {
568 deliver(skb, r);
569 matches++;
570 }
571 }
572 return matches;
573 }
574
575 /* check for unfiltered entries */
576 hlist_for_each_entry_rcu(r, n, &d->rx[RX_ALL], list) {
577 deliver(skb, r);
578 matches++;
579 }
580
581 /* check for can_id/mask entries */
582 hlist_for_each_entry_rcu(r, n, &d->rx[RX_FIL], list) {
583 if ((can_id & r->mask) == r->can_id) {
584 deliver(skb, r);
585 matches++;
586 }
587 }
588
589 /* check for inverted can_id/mask entries */
590 hlist_for_each_entry_rcu(r, n, &d->rx[RX_INV], list) {
591 if ((can_id & r->mask) != r->can_id) {
592 deliver(skb, r);
593 matches++;
594 }
595 }
596
597 /* check filterlists for single non-RTR can_ids */
598 if (can_id & CAN_RTR_FLAG)
599 return matches;
600
601 if (can_id & CAN_EFF_FLAG) {
602 hlist_for_each_entry_rcu(r, n, &d->rx[RX_EFF], list) {
603 if (r->can_id == can_id) {
604 deliver(skb, r);
605 matches++;
606 }
607 }
608 } else {
609 can_id &= CAN_SFF_MASK;
610 hlist_for_each_entry_rcu(r, n, &d->rx_sff[can_id], list) {
611 deliver(skb, r);
612 matches++;
613 }
614 }
615
616 return matches;
617 }
618
can_rcv(struct sk_buff * skb,struct net_device * dev,struct packet_type * pt,struct net_device * orig_dev)619 static int can_rcv(struct sk_buff *skb, struct net_device *dev,
620 struct packet_type *pt, struct net_device *orig_dev)
621 {
622 struct dev_rcv_lists *d;
623 struct can_frame *cf = (struct can_frame *)skb->data;
624 int matches;
625
626 if (!net_eq(dev_net(dev), &init_net))
627 goto drop;
628
629 if (WARN_ONCE(dev->type != ARPHRD_CAN ||
630 skb->len != sizeof(struct can_frame) ||
631 cf->can_dlc > 8,
632 "PF_CAN: dropped non conform skbuf: "
633 "dev type %d, len %d, can_dlc %d\n",
634 dev->type, skb->len, cf->can_dlc))
635 goto drop;
636
637 /* update statistics */
638 can_stats.rx_frames++;
639 can_stats.rx_frames_delta++;
640
641 rcu_read_lock();
642
643 /* deliver the packet to sockets listening on all devices */
644 matches = can_rcv_filter(&can_rx_alldev_list, skb);
645
646 /* find receive list for this device */
647 d = find_dev_rcv_lists(dev);
648 if (d)
649 matches += can_rcv_filter(d, skb);
650
651 rcu_read_unlock();
652
653 /* consume the skbuff allocated by the netdevice driver */
654 consume_skb(skb);
655
656 if (matches > 0) {
657 can_stats.matches++;
658 can_stats.matches_delta++;
659 }
660
661 return NET_RX_SUCCESS;
662
663 drop:
664 kfree_skb(skb);
665 return NET_RX_DROP;
666 }
667
668 /*
669 * af_can protocol functions
670 */
671
672 /**
673 * can_proto_register - register CAN transport protocol
674 * @cp: pointer to CAN protocol structure
675 *
676 * Return:
677 * 0 on success
678 * -EINVAL invalid (out of range) protocol number
679 * -EBUSY protocol already in use
680 * -ENOBUF if proto_register() fails
681 */
can_proto_register(struct can_proto * cp)682 int can_proto_register(struct can_proto *cp)
683 {
684 int proto = cp->protocol;
685 int err = 0;
686
687 if (proto < 0 || proto >= CAN_NPROTO) {
688 printk(KERN_ERR "can: protocol number %d out of range\n",
689 proto);
690 return -EINVAL;
691 }
692
693 err = proto_register(cp->prot, 0);
694 if (err < 0)
695 return err;
696
697 spin_lock(&proto_tab_lock);
698 if (proto_tab[proto]) {
699 printk(KERN_ERR "can: protocol %d already registered\n",
700 proto);
701 err = -EBUSY;
702 } else
703 proto_tab[proto] = cp;
704
705 spin_unlock(&proto_tab_lock);
706
707 if (err < 0)
708 proto_unregister(cp->prot);
709
710 return err;
711 }
712 EXPORT_SYMBOL(can_proto_register);
713
714 /**
715 * can_proto_unregister - unregister CAN transport protocol
716 * @cp: pointer to CAN protocol structure
717 */
can_proto_unregister(struct can_proto * cp)718 void can_proto_unregister(struct can_proto *cp)
719 {
720 int proto = cp->protocol;
721
722 spin_lock(&proto_tab_lock);
723 if (!proto_tab[proto]) {
724 printk(KERN_ERR "BUG: can: protocol %d is not registered\n",
725 proto);
726 }
727 proto_tab[proto] = NULL;
728 spin_unlock(&proto_tab_lock);
729
730 proto_unregister(cp->prot);
731 }
732 EXPORT_SYMBOL(can_proto_unregister);
733
734 /*
735 * af_can notifier to create/remove CAN netdevice specific structs
736 */
can_notifier(struct notifier_block * nb,unsigned long msg,void * data)737 static int can_notifier(struct notifier_block *nb, unsigned long msg,
738 void *data)
739 {
740 struct net_device *dev = (struct net_device *)data;
741 struct dev_rcv_lists *d;
742
743 if (!net_eq(dev_net(dev), &init_net))
744 return NOTIFY_DONE;
745
746 if (dev->type != ARPHRD_CAN)
747 return NOTIFY_DONE;
748
749 switch (msg) {
750
751 case NETDEV_REGISTER:
752
753 /* create new dev_rcv_lists for this device */
754 d = kzalloc(sizeof(*d), GFP_KERNEL);
755 if (!d) {
756 printk(KERN_ERR
757 "can: allocation of receive list failed\n");
758 return NOTIFY_DONE;
759 }
760 BUG_ON(dev->ml_priv);
761 dev->ml_priv = d;
762
763 break;
764
765 case NETDEV_UNREGISTER:
766 spin_lock(&can_rcvlists_lock);
767
768 d = dev->ml_priv;
769 if (d) {
770 if (d->entries)
771 d->remove_on_zero_entries = 1;
772 else {
773 kfree(d);
774 dev->ml_priv = NULL;
775 }
776 } else
777 printk(KERN_ERR "can: notifier: receive list not "
778 "found for dev %s\n", dev->name);
779
780 spin_unlock(&can_rcvlists_lock);
781
782 break;
783 }
784
785 return NOTIFY_DONE;
786 }
787
788 /*
789 * af_can module init/exit functions
790 */
791
792 static struct packet_type can_packet __read_mostly = {
793 .type = cpu_to_be16(ETH_P_CAN),
794 .dev = NULL,
795 .func = can_rcv,
796 };
797
798 static const struct net_proto_family can_family_ops = {
799 .family = PF_CAN,
800 .create = can_create,
801 .owner = THIS_MODULE,
802 };
803
804 /* notifier block for netdevice event */
805 static struct notifier_block can_netdev_notifier __read_mostly = {
806 .notifier_call = can_notifier,
807 };
808
can_init(void)809 static __init int can_init(void)
810 {
811 printk(banner);
812
813 memset(&can_rx_alldev_list, 0, sizeof(can_rx_alldev_list));
814
815 rcv_cache = kmem_cache_create("can_receiver", sizeof(struct receiver),
816 0, 0, NULL);
817 if (!rcv_cache)
818 return -ENOMEM;
819
820 if (stats_timer) {
821 /* the statistics are updated every second (timer triggered) */
822 setup_timer(&can_stattimer, can_stat_update, 0);
823 mod_timer(&can_stattimer, round_jiffies(jiffies + HZ));
824 } else
825 can_stattimer.function = NULL;
826
827 can_init_proc();
828
829 /* protocol register */
830 sock_register(&can_family_ops);
831 register_netdevice_notifier(&can_netdev_notifier);
832 dev_add_pack(&can_packet);
833
834 return 0;
835 }
836
can_exit(void)837 static __exit void can_exit(void)
838 {
839 struct net_device *dev;
840
841 if (stats_timer)
842 del_timer(&can_stattimer);
843
844 can_remove_proc();
845
846 /* protocol unregister */
847 dev_remove_pack(&can_packet);
848 unregister_netdevice_notifier(&can_netdev_notifier);
849 sock_unregister(PF_CAN);
850
851 /* remove created dev_rcv_lists from still registered CAN devices */
852 rcu_read_lock();
853 for_each_netdev_rcu(&init_net, dev) {
854 if (dev->type == ARPHRD_CAN && dev->ml_priv){
855
856 struct dev_rcv_lists *d = dev->ml_priv;
857
858 BUG_ON(d->entries);
859 kfree(d);
860 dev->ml_priv = NULL;
861 }
862 }
863 rcu_read_unlock();
864
865 rcu_barrier(); /* Wait for completion of call_rcu()'s */
866
867 kmem_cache_destroy(rcv_cache);
868 }
869
870 module_init(can_init);
871 module_exit(can_exit);
872