blob: 8035fbf526ae24e5fabff5b1c588abb8769e3c67 [file] [log] [blame]
Oliver Hartkopp0d665482007-11-16 15:52:17 -08001/*
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
66static __initdata const char banner[] = KERN_INFO
67 "can: controller area network core (" CAN_VERSION_STRING ")\n";
68
69MODULE_DESCRIPTION("Controller Area Network PF_CAN core");
70MODULE_LICENSE("Dual BSD/GPL");
71MODULE_AUTHOR("Urs Thuermann <urs.thuermann@volkswagen.de>, "
72 "Oliver Hartkopp <oliver.hartkopp@volkswagen.de>");
73
74MODULE_ALIAS_NETPROTO(PF_CAN);
75
76static int stats_timer __read_mostly = 1;
77module_param(stats_timer, int, S_IRUGO);
78MODULE_PARM_DESC(stats_timer, "enable timer for statistics (default:on)");
79
80HLIST_HEAD(can_rx_dev_list);
81static struct dev_rcv_lists can_rx_alldev_list;
82static DEFINE_SPINLOCK(can_rcvlists_lock);
83
84static struct kmem_cache *rcv_cache __read_mostly;
85
86/* table of registered CAN protocols */
87static struct can_proto *proto_tab[CAN_NPROTO] __read_mostly;
88static DEFINE_SPINLOCK(proto_tab_lock);
89
90struct timer_list can_stattimer; /* timer for statistics update */
91struct s_stats can_stats; /* packet statistics */
92struct s_pstats can_pstats; /* receive list statistics */
93
94/*
95 * af_can socket functions
96 */
97
98static 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
112static void can_sock_destruct(struct sock *sk)
113{
114 skb_queue_purge(&sk->sk_receive_queue);
115}
116
117static int can_create(struct net *net, struct socket *sock, int protocol)
118{
119 struct sock *sk;
120 struct can_proto *cp;
Oliver Hartkopp0d665482007-11-16 15:52:17 -0800121 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
Urs Thuermann5423dd62008-02-07 18:04:21 -0800131#ifdef CONFIG_KMOD
Oliver Hartkopp0d665482007-11-16 15:52:17 -0800132 /* try to load protocol module, when CONFIG_KMOD is defined */
133 if (!proto_tab[protocol]) {
Urs Thuermann5423dd62008-02-07 18:04:21 -0800134 err = request_module("can-proto-%d", protocol);
Oliver Hartkopp0d665482007-11-16 15:52:17 -0800135
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 */
Urs Thuermann5423dd62008-02-07 18:04:21 -0800141 if (err && printk_ratelimit())
142 printk(KERN_ERR "can: request_module "
143 "(can-proto-%d) failed.\n", protocol);
Oliver Hartkopp0d665482007-11-16 15:52:17 -0800144 }
Urs Thuermann5423dd62008-02-07 18:04:21 -0800145#endif
Oliver Hartkopp0d665482007-11-16 15:52:17 -0800146
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 * Return:
203 * 0 on success
204 * -ENETDOWN when the selected interface is down
205 * -ENOBUFS on full driver queue (see net_xmit_errno())
206 * -ENOMEM when local loopback failed at calling skb_clone()
207 * -EPERM when trying to send on a non-CAN interface
Oliver Hartkopp7f2d38e2008-07-05 23:38:43 -0700208 * -EINVAL when the skb->data does not contain a valid CAN frame
Oliver Hartkopp0d665482007-11-16 15:52:17 -0800209 */
210int can_send(struct sk_buff *skb, int loop)
211{
Oliver Hartkoppc2ab7ac2008-05-08 02:49:55 -0700212 struct sk_buff *newskb = NULL;
Oliver Hartkopp7f2d38e2008-07-05 23:38:43 -0700213 struct can_frame *cf = (struct can_frame *)skb->data;
Oliver Hartkopp0d665482007-11-16 15:52:17 -0800214 int err;
215
Oliver Hartkopp7f2d38e2008-07-05 23:38:43 -0700216 if (skb->len != sizeof(struct can_frame) || cf->can_dlc > 8) {
217 kfree_skb(skb);
218 return -EINVAL;
219 }
220
Oliver Hartkopp0d665482007-11-16 15:52:17 -0800221 if (skb->dev->type != ARPHRD_CAN) {
222 kfree_skb(skb);
223 return -EPERM;
224 }
225
226 if (!(skb->dev->flags & IFF_UP)) {
227 kfree_skb(skb);
228 return -ENETDOWN;
229 }
230
231 skb->protocol = htons(ETH_P_CAN);
232 skb_reset_network_header(skb);
233 skb_reset_transport_header(skb);
234
235 if (loop) {
236 /* local loopback of sent CAN frames */
237
238 /* indication for the CAN driver: do loopback */
239 skb->pkt_type = PACKET_LOOPBACK;
240
241 /*
242 * The reference to the originating sock may be required
243 * by the receiving socket to check whether the frame is
244 * its own. Example: can_raw sockopt CAN_RAW_RECV_OWN_MSGS
245 * Therefore we have to ensure that skb->sk remains the
246 * reference to the originating sock by restoring skb->sk
247 * after each skb_clone() or skb_orphan() usage.
248 */
249
250 if (!(skb->dev->flags & IFF_ECHO)) {
251 /*
252 * If the interface is not capable to do loopback
253 * itself, we do it here.
254 */
Oliver Hartkoppc2ab7ac2008-05-08 02:49:55 -0700255 newskb = skb_clone(skb, GFP_ATOMIC);
Oliver Hartkopp0d665482007-11-16 15:52:17 -0800256 if (!newskb) {
257 kfree_skb(skb);
258 return -ENOMEM;
259 }
260
261 newskb->sk = skb->sk;
262 newskb->ip_summed = CHECKSUM_UNNECESSARY;
263 newskb->pkt_type = PACKET_BROADCAST;
Oliver Hartkopp0d665482007-11-16 15:52:17 -0800264 }
265 } else {
266 /* indication for the CAN driver: no loopback required */
267 skb->pkt_type = PACKET_HOST;
268 }
269
270 /* send to netdevice */
271 err = dev_queue_xmit(skb);
272 if (err > 0)
273 err = net_xmit_errno(err);
274
Oliver Hartkoppc2ab7ac2008-05-08 02:49:55 -0700275 if (err) {
276 if (newskb)
277 kfree_skb(newskb);
278 return err;
279 }
280
281 if (newskb)
282 netif_rx(newskb);
283
Oliver Hartkopp0d665482007-11-16 15:52:17 -0800284 /* update statistics */
285 can_stats.tx_frames++;
286 can_stats.tx_frames_delta++;
287
Oliver Hartkoppc2ab7ac2008-05-08 02:49:55 -0700288 return 0;
Oliver Hartkopp0d665482007-11-16 15:52:17 -0800289}
290EXPORT_SYMBOL(can_send);
291
292/*
293 * af_can rx path
294 */
295
296static struct dev_rcv_lists *find_dev_rcv_lists(struct net_device *dev)
297{
298 struct dev_rcv_lists *d = NULL;
299 struct hlist_node *n;
300
301 /*
302 * find receive list for this device
303 *
304 * The hlist_for_each_entry*() macros curse through the list
305 * using the pointer variable n and set d to the containing
306 * struct in each list iteration. Therefore, after list
307 * iteration, d is unmodified when the list is empty, and it
308 * points to last list element, when the list is non-empty
309 * but no match in the loop body is found. I.e. d is *not*
310 * NULL when no match is found. We can, however, use the
311 * cursor variable n to decide if a match was found.
312 */
313
314 hlist_for_each_entry_rcu(d, n, &can_rx_dev_list, list) {
315 if (d->dev == dev)
316 break;
317 }
318
319 return n ? d : NULL;
320}
321
322static struct hlist_head *find_rcv_list(canid_t *can_id, canid_t *mask,
323 struct dev_rcv_lists *d)
324{
325 canid_t inv = *can_id & CAN_INV_FILTER; /* save flag before masking */
326
327 /* filter error frames */
328 if (*mask & CAN_ERR_FLAG) {
329 /* clear CAN_ERR_FLAG in list entry */
330 *mask &= CAN_ERR_MASK;
331 return &d->rx[RX_ERR];
332 }
333
334 /* ensure valid values in can_mask */
335 if (*mask & CAN_EFF_FLAG)
336 *mask &= (CAN_EFF_MASK | CAN_EFF_FLAG | CAN_RTR_FLAG);
337 else
338 *mask &= (CAN_SFF_MASK | CAN_RTR_FLAG);
339
340 /* reduce condition testing at receive time */
341 *can_id &= *mask;
342
343 /* inverse can_id/can_mask filter */
344 if (inv)
345 return &d->rx[RX_INV];
346
347 /* mask == 0 => no condition testing at receive time */
348 if (!(*mask))
349 return &d->rx[RX_ALL];
350
351 /* use extra filterset for the subscription of exactly *ONE* can_id */
352 if (*can_id & CAN_EFF_FLAG) {
353 if (*mask == (CAN_EFF_MASK | CAN_EFF_FLAG)) {
354 /* RFC: a use-case for hash-tables in the future? */
355 return &d->rx[RX_EFF];
356 }
357 } else {
358 if (*mask == CAN_SFF_MASK)
359 return &d->rx_sff[*can_id];
360 }
361
362 /* default: filter via can_id/can_mask */
363 return &d->rx[RX_FIL];
364}
365
366/**
367 * can_rx_register - subscribe CAN frames from a specific interface
368 * @dev: pointer to netdevice (NULL => subcribe from 'all' CAN devices list)
369 * @can_id: CAN identifier (see description)
370 * @mask: CAN mask (see description)
371 * @func: callback function on filter match
372 * @data: returned parameter for callback function
373 * @ident: string for calling module indentification
374 *
375 * Description:
376 * Invokes the callback function with the received sk_buff and the given
377 * parameter 'data' on a matching receive filter. A filter matches, when
378 *
379 * <received_can_id> & mask == can_id & mask
380 *
381 * The filter can be inverted (CAN_INV_FILTER bit set in can_id) or it can
382 * filter for error frames (CAN_ERR_FLAG bit set in mask).
383 *
384 * Return:
385 * 0 on success
386 * -ENOMEM on missing cache mem to create subscription entry
387 * -ENODEV unknown device
388 */
389int can_rx_register(struct net_device *dev, canid_t can_id, canid_t mask,
390 void (*func)(struct sk_buff *, void *), void *data,
391 char *ident)
392{
393 struct receiver *r;
394 struct hlist_head *rl;
395 struct dev_rcv_lists *d;
396 int err = 0;
397
398 /* insert new receiver (dev,canid,mask) -> (func,data) */
399
400 r = kmem_cache_alloc(rcv_cache, GFP_KERNEL);
401 if (!r)
402 return -ENOMEM;
403
404 spin_lock(&can_rcvlists_lock);
405
406 d = find_dev_rcv_lists(dev);
407 if (d) {
408 rl = find_rcv_list(&can_id, &mask, d);
409
410 r->can_id = can_id;
411 r->mask = mask;
412 r->matches = 0;
413 r->func = func;
414 r->data = data;
415 r->ident = ident;
416
417 hlist_add_head_rcu(&r->list, rl);
418 d->entries++;
419
420 can_pstats.rcv_entries++;
421 if (can_pstats.rcv_entries_max < can_pstats.rcv_entries)
422 can_pstats.rcv_entries_max = can_pstats.rcv_entries;
423 } else {
424 kmem_cache_free(rcv_cache, r);
425 err = -ENODEV;
426 }
427
428 spin_unlock(&can_rcvlists_lock);
429
430 return err;
431}
432EXPORT_SYMBOL(can_rx_register);
433
434/*
435 * can_rx_delete_device - rcu callback for dev_rcv_lists structure removal
436 */
437static void can_rx_delete_device(struct rcu_head *rp)
438{
439 struct dev_rcv_lists *d = container_of(rp, struct dev_rcv_lists, rcu);
440
441 kfree(d);
442}
443
444/*
445 * can_rx_delete_receiver - rcu callback for single receiver entry removal
446 */
447static void can_rx_delete_receiver(struct rcu_head *rp)
448{
449 struct receiver *r = container_of(rp, struct receiver, rcu);
450
451 kmem_cache_free(rcv_cache, r);
452}
453
454/**
455 * can_rx_unregister - unsubscribe CAN frames from a specific interface
456 * @dev: pointer to netdevice (NULL => unsubcribe from 'all' CAN devices list)
457 * @can_id: CAN identifier
458 * @mask: CAN mask
459 * @func: callback function on filter match
460 * @data: returned parameter for callback function
461 *
462 * Description:
463 * Removes subscription entry depending on given (subscription) values.
464 */
465void can_rx_unregister(struct net_device *dev, canid_t can_id, canid_t mask,
466 void (*func)(struct sk_buff *, void *), void *data)
467{
468 struct receiver *r = NULL;
469 struct hlist_head *rl;
470 struct hlist_node *next;
471 struct dev_rcv_lists *d;
472
473 spin_lock(&can_rcvlists_lock);
474
475 d = find_dev_rcv_lists(dev);
476 if (!d) {
477 printk(KERN_ERR "BUG: receive list not found for "
478 "dev %s, id %03X, mask %03X\n",
479 DNAME(dev), can_id, mask);
480 goto out;
481 }
482
483 rl = find_rcv_list(&can_id, &mask, d);
484
485 /*
486 * Search the receiver list for the item to delete. This should
487 * exist, since no receiver may be unregistered that hasn't
488 * been registered before.
489 */
490
491 hlist_for_each_entry_rcu(r, next, rl, list) {
492 if (r->can_id == can_id && r->mask == mask
493 && r->func == func && r->data == data)
494 break;
495 }
496
497 /*
498 * Check for bugs in CAN protocol implementations:
499 * If no matching list item was found, the list cursor variable next
500 * will be NULL, while r will point to the last item of the list.
501 */
502
503 if (!next) {
504 printk(KERN_ERR "BUG: receive list entry not found for "
505 "dev %s, id %03X, mask %03X\n",
506 DNAME(dev), can_id, mask);
507 r = NULL;
508 d = NULL;
509 goto out;
510 }
511
512 hlist_del_rcu(&r->list);
513 d->entries--;
514
515 if (can_pstats.rcv_entries > 0)
516 can_pstats.rcv_entries--;
517
518 /* remove device structure requested by NETDEV_UNREGISTER */
519 if (d->remove_on_zero_entries && !d->entries)
520 hlist_del_rcu(&d->list);
521 else
522 d = NULL;
523
524 out:
525 spin_unlock(&can_rcvlists_lock);
526
527 /* schedule the receiver item for deletion */
528 if (r)
529 call_rcu(&r->rcu, can_rx_delete_receiver);
530
531 /* schedule the device structure for deletion */
532 if (d)
533 call_rcu(&d->rcu, can_rx_delete_device);
534}
535EXPORT_SYMBOL(can_rx_unregister);
536
537static inline void deliver(struct sk_buff *skb, struct receiver *r)
538{
539 struct sk_buff *clone = skb_clone(skb, GFP_ATOMIC);
540
541 if (clone) {
542 clone->sk = skb->sk;
543 r->func(clone, r->data);
544 r->matches++;
545 }
546}
547
548static int can_rcv_filter(struct dev_rcv_lists *d, struct sk_buff *skb)
549{
550 struct receiver *r;
551 struct hlist_node *n;
552 int matches = 0;
553 struct can_frame *cf = (struct can_frame *)skb->data;
554 canid_t can_id = cf->can_id;
555
556 if (d->entries == 0)
557 return 0;
558
559 if (can_id & CAN_ERR_FLAG) {
560 /* check for error frame entries only */
561 hlist_for_each_entry_rcu(r, n, &d->rx[RX_ERR], list) {
562 if (can_id & r->mask) {
563 deliver(skb, r);
564 matches++;
565 }
566 }
567 return matches;
568 }
569
570 /* check for unfiltered entries */
571 hlist_for_each_entry_rcu(r, n, &d->rx[RX_ALL], list) {
572 deliver(skb, r);
573 matches++;
574 }
575
576 /* check for can_id/mask entries */
577 hlist_for_each_entry_rcu(r, n, &d->rx[RX_FIL], list) {
578 if ((can_id & r->mask) == r->can_id) {
579 deliver(skb, r);
580 matches++;
581 }
582 }
583
584 /* check for inverted can_id/mask entries */
585 hlist_for_each_entry_rcu(r, n, &d->rx[RX_INV], list) {
586 if ((can_id & r->mask) != r->can_id) {
587 deliver(skb, r);
588 matches++;
589 }
590 }
591
592 /* check CAN_ID specific entries */
593 if (can_id & CAN_EFF_FLAG) {
594 hlist_for_each_entry_rcu(r, n, &d->rx[RX_EFF], list) {
595 if (r->can_id == can_id) {
596 deliver(skb, r);
597 matches++;
598 }
599 }
600 } else {
601 can_id &= CAN_SFF_MASK;
602 hlist_for_each_entry_rcu(r, n, &d->rx_sff[can_id], list) {
603 deliver(skb, r);
604 matches++;
605 }
606 }
607
608 return matches;
609}
610
611static int can_rcv(struct sk_buff *skb, struct net_device *dev,
612 struct packet_type *pt, struct net_device *orig_dev)
613{
614 struct dev_rcv_lists *d;
Oliver Hartkopp7f2d38e2008-07-05 23:38:43 -0700615 struct can_frame *cf = (struct can_frame *)skb->data;
Oliver Hartkopp0d665482007-11-16 15:52:17 -0800616 int matches;
617
YOSHIFUJI Hideaki721499e2008-07-19 22:34:43 -0700618 if (dev->type != ARPHRD_CAN || !net_eq(dev_net(dev), &init_net)) {
Oliver Hartkopp0d665482007-11-16 15:52:17 -0800619 kfree_skb(skb);
620 return 0;
621 }
622
Oliver Hartkopp7f2d38e2008-07-05 23:38:43 -0700623 BUG_ON(skb->len != sizeof(struct can_frame) || cf->can_dlc > 8);
624
Oliver Hartkopp0d665482007-11-16 15:52:17 -0800625 /* update statistics */
626 can_stats.rx_frames++;
627 can_stats.rx_frames_delta++;
628
629 rcu_read_lock();
630
631 /* deliver the packet to sockets listening on all devices */
632 matches = can_rcv_filter(&can_rx_alldev_list, skb);
633
634 /* find receive list for this device */
635 d = find_dev_rcv_lists(dev);
636 if (d)
637 matches += can_rcv_filter(d, skb);
638
639 rcu_read_unlock();
640
641 /* free the skbuff allocated by the netdevice driver */
642 kfree_skb(skb);
643
644 if (matches > 0) {
645 can_stats.matches++;
646 can_stats.matches_delta++;
647 }
648
649 return 0;
650}
651
652/*
653 * af_can protocol functions
654 */
655
656/**
657 * can_proto_register - register CAN transport protocol
658 * @cp: pointer to CAN protocol structure
659 *
660 * Return:
661 * 0 on success
662 * -EINVAL invalid (out of range) protocol number
663 * -EBUSY protocol already in use
664 * -ENOBUF if proto_register() fails
665 */
666int can_proto_register(struct can_proto *cp)
667{
668 int proto = cp->protocol;
669 int err = 0;
670
671 if (proto < 0 || proto >= CAN_NPROTO) {
672 printk(KERN_ERR "can: protocol number %d out of range\n",
673 proto);
674 return -EINVAL;
675 }
676
Urs Thuermanna2fea5f2008-02-07 18:04:45 -0800677 err = proto_register(cp->prot, 0);
678 if (err < 0)
679 return err;
680
Oliver Hartkopp0d665482007-11-16 15:52:17 -0800681 spin_lock(&proto_tab_lock);
682 if (proto_tab[proto]) {
683 printk(KERN_ERR "can: protocol %d already registered\n",
684 proto);
685 err = -EBUSY;
Urs Thuermanna2fea5f2008-02-07 18:04:45 -0800686 } else {
687 proto_tab[proto] = cp;
688
689 /* use generic ioctl function if not defined by module */
690 if (!cp->ops->ioctl)
691 cp->ops->ioctl = can_ioctl;
Oliver Hartkopp0d665482007-11-16 15:52:17 -0800692 }
Oliver Hartkopp0d665482007-11-16 15:52:17 -0800693 spin_unlock(&proto_tab_lock);
694
Urs Thuermanna2fea5f2008-02-07 18:04:45 -0800695 if (err < 0)
696 proto_unregister(cp->prot);
697
Oliver Hartkopp0d665482007-11-16 15:52:17 -0800698 return err;
699}
700EXPORT_SYMBOL(can_proto_register);
701
702/**
703 * can_proto_unregister - unregister CAN transport protocol
704 * @cp: pointer to CAN protocol structure
705 */
706void can_proto_unregister(struct can_proto *cp)
707{
708 int proto = cp->protocol;
709
710 spin_lock(&proto_tab_lock);
711 if (!proto_tab[proto]) {
712 printk(KERN_ERR "BUG: can: protocol %d is not registered\n",
713 proto);
714 }
Oliver Hartkopp0d665482007-11-16 15:52:17 -0800715 proto_tab[proto] = NULL;
716 spin_unlock(&proto_tab_lock);
Urs Thuermanna2fea5f2008-02-07 18:04:45 -0800717
718 proto_unregister(cp->prot);
Oliver Hartkopp0d665482007-11-16 15:52:17 -0800719}
720EXPORT_SYMBOL(can_proto_unregister);
721
722/*
723 * af_can notifier to create/remove CAN netdevice specific structs
724 */
725static int can_notifier(struct notifier_block *nb, unsigned long msg,
726 void *data)
727{
728 struct net_device *dev = (struct net_device *)data;
729 struct dev_rcv_lists *d;
730
YOSHIFUJI Hideaki721499e2008-07-19 22:34:43 -0700731 if (!net_eq(dev_net(dev), &init_net))
Oliver Hartkopp0d665482007-11-16 15:52:17 -0800732 return NOTIFY_DONE;
733
734 if (dev->type != ARPHRD_CAN)
735 return NOTIFY_DONE;
736
737 switch (msg) {
738
739 case NETDEV_REGISTER:
740
741 /*
742 * create new dev_rcv_lists for this device
743 *
744 * N.B. zeroing the struct is the correct initialization
745 * for the embedded hlist_head structs.
746 * Another list type, e.g. list_head, would require
747 * explicit initialization.
748 */
749
750 d = kzalloc(sizeof(*d), GFP_KERNEL);
751 if (!d) {
752 printk(KERN_ERR
753 "can: allocation of receive list failed\n");
754 return NOTIFY_DONE;
755 }
756 d->dev = dev;
757
758 spin_lock(&can_rcvlists_lock);
759 hlist_add_head_rcu(&d->list, &can_rx_dev_list);
760 spin_unlock(&can_rcvlists_lock);
761
762 break;
763
764 case NETDEV_UNREGISTER:
765 spin_lock(&can_rcvlists_lock);
766
767 d = find_dev_rcv_lists(dev);
768 if (d) {
769 if (d->entries) {
770 d->remove_on_zero_entries = 1;
771 d = NULL;
772 } else
773 hlist_del_rcu(&d->list);
774 } else
775 printk(KERN_ERR "can: notifier: receive list not "
776 "found for dev %s\n", dev->name);
777
778 spin_unlock(&can_rcvlists_lock);
779
780 if (d)
781 call_rcu(&d->rcu, can_rx_delete_device);
782
783 break;
784 }
785
786 return NOTIFY_DONE;
787}
788
789/*
790 * af_can module init/exit functions
791 */
792
793static struct packet_type can_packet __read_mostly = {
794 .type = __constant_htons(ETH_P_CAN),
795 .dev = NULL,
796 .func = can_rcv,
797};
798
799static struct net_proto_family can_family_ops __read_mostly = {
800 .family = PF_CAN,
801 .create = can_create,
802 .owner = THIS_MODULE,
803};
804
805/* notifier block for netdevice event */
806static struct notifier_block can_netdev_notifier __read_mostly = {
807 .notifier_call = can_notifier,
808};
809
810static __init int can_init(void)
811{
812 printk(banner);
813
814 rcv_cache = kmem_cache_create("can_receiver", sizeof(struct receiver),
815 0, 0, NULL);
816 if (!rcv_cache)
817 return -ENOMEM;
818
819 /*
820 * Insert can_rx_alldev_list for reception on all devices.
821 * This struct is zero initialized which is correct for the
822 * embedded hlist heads, the dev pointer, and the entries counter.
823 */
824
825 spin_lock(&can_rcvlists_lock);
826 hlist_add_head_rcu(&can_rx_alldev_list.list, &can_rx_dev_list);
827 spin_unlock(&can_rcvlists_lock);
828
829 if (stats_timer) {
830 /* the statistics are updated every second (timer triggered) */
831 setup_timer(&can_stattimer, can_stat_update, 0);
832 mod_timer(&can_stattimer, round_jiffies(jiffies + HZ));
833 } else
834 can_stattimer.function = NULL;
835
836 can_init_proc();
837
838 /* protocol register */
839 sock_register(&can_family_ops);
840 register_netdevice_notifier(&can_netdev_notifier);
841 dev_add_pack(&can_packet);
842
843 return 0;
844}
845
846static __exit void can_exit(void)
847{
848 struct dev_rcv_lists *d;
849 struct hlist_node *n, *next;
850
851 if (stats_timer)
852 del_timer(&can_stattimer);
853
854 can_remove_proc();
855
856 /* protocol unregister */
857 dev_remove_pack(&can_packet);
858 unregister_netdevice_notifier(&can_netdev_notifier);
859 sock_unregister(PF_CAN);
860
861 /* remove can_rx_dev_list */
862 spin_lock(&can_rcvlists_lock);
863 hlist_del(&can_rx_alldev_list.list);
864 hlist_for_each_entry_safe(d, n, next, &can_rx_dev_list, list) {
865 hlist_del(&d->list);
866 kfree(d);
867 }
868 spin_unlock(&can_rcvlists_lock);
869
870 kmem_cache_destroy(rcv_cache);
871}
872
873module_init(can_init);
874module_exit(can_exit);