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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/stddef.h>
45#include <linux/init.h>
46#include <linux/kmod.h>
47#include <linux/slab.h>
48#include <linux/list.h>
49#include <linux/spinlock.h>
50#include <linux/rcupdate.h>
51#include <linux/uaccess.h>
52#include <linux/net.h>
53#include <linux/netdevice.h>
54#include <linux/socket.h>
55#include <linux/if_ether.h>
56#include <linux/if_arp.h>
57#include <linux/skbuff.h>
58#include <linux/can.h>
59#include <linux/can/core.h>
60#include <linux/can/skb.h>
61#include <linux/ratelimit.h>
62#include <net/net_namespace.h>
63#include <net/sock.h>
64
65#include "af_can.h"
66
67MODULE_DESCRIPTION("Controller Area Network PF_CAN core");
68MODULE_LICENSE("Dual BSD/GPL");
69MODULE_AUTHOR("Urs Thuermann <urs.thuermann@volkswagen.de>, "
70 "Oliver Hartkopp <oliver.hartkopp@volkswagen.de>");
71
72MODULE_ALIAS_NETPROTO(PF_CAN);
73
74static int stats_timer __read_mostly = 1;
75module_param(stats_timer, int, S_IRUGO);
76MODULE_PARM_DESC(stats_timer, "enable timer for statistics (default:on)");
77
78/* receive filters subscribed for 'all' CAN devices */
79struct dev_rcv_lists can_rx_alldev_list;
80static DEFINE_SPINLOCK(can_rcvlists_lock);
81
82static struct kmem_cache *rcv_cache __read_mostly;
83
84/* table of registered CAN protocols */
85static const struct can_proto *proto_tab[CAN_NPROTO] __read_mostly;
86static DEFINE_MUTEX(proto_tab_lock);
87
88struct timer_list can_stattimer; /* timer for statistics update */
89struct s_stats can_stats; /* packet statistics */
90struct s_pstats can_pstats; /* receive list statistics */
91
92static atomic_t skbcounter = ATOMIC_INIT(0);
93
94/*
95 * af_can socket functions
96 */
97
98int 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}
111EXPORT_SYMBOL(can_ioctl);
112
113static void can_sock_destruct(struct sock *sk)
114{
115 skb_queue_purge(&sk->sk_receive_queue);
116}
117
118static const struct can_proto *can_get_proto(int protocol)
119{
120 const struct can_proto *cp;
121
122 rcu_read_lock();
123 cp = rcu_dereference(proto_tab[protocol]);
124 if (cp && !try_module_get(cp->prot->owner))
125 cp = NULL;
126 rcu_read_unlock();
127
128 return cp;
129}
130
131static inline void can_put_proto(const struct can_proto *cp)
132{
133 module_put(cp->prot->owner);
134}
135
136static int can_create(struct net *net, struct socket *sock, int protocol,
137 int kern)
138{
139 struct sock *sk;
140 const struct can_proto *cp;
141 int err = 0;
142
143 sock->state = SS_UNCONNECTED;
144
145 if (protocol < 0 || protocol >= CAN_NPROTO)
146 return -EINVAL;
147
148 if (!net_eq(net, &init_net))
149 return -EAFNOSUPPORT;
150
151 cp = can_get_proto(protocol);
152
153#ifdef CONFIG_MODULES
154 if (!cp) {
155 /* try to load protocol module if kernel is modular */
156
157 err = request_module("can-proto-%d", protocol);
158
159 /*
160 * In case of error we only print a message but don't
161 * return the error code immediately. Below we will
162 * return -EPROTONOSUPPORT
163 */
164 if (err)
165 printk_ratelimited(KERN_ERR "can: request_module "
166 "(can-proto-%d) failed.\n", protocol);
167
168 cp = can_get_proto(protocol);
169 }
170#endif
171
172 /* check for available protocol and correct usage */
173
174 if (!cp)
175 return -EPROTONOSUPPORT;
176
177 if (cp->type != sock->type) {
178 err = -EPROTOTYPE;
179 goto errout;
180 }
181
182 sock->ops = cp->ops;
183
184 sk = sk_alloc(net, PF_CAN, GFP_KERNEL, cp->prot, kern);
185 if (!sk) {
186 err = -ENOMEM;
187 goto errout;
188 }
189
190 sock_init_data(sock, sk);
191 sk->sk_destruct = can_sock_destruct;
192
193 if (sk->sk_prot->init)
194 err = sk->sk_prot->init(sk);
195
196 if (err) {
197 /* release sk on errors */
198 sock_orphan(sk);
199 sock_put(sk);
200 }
201
202 errout:
203 can_put_proto(cp);
204 return err;
205}
206
207/*
208 * af_can tx path
209 */
210
211/**
212 * can_send - transmit a CAN frame (optional with local loopback)
213 * @skb: pointer to socket buffer with CAN frame in data section
214 * @loop: loopback for listeners on local CAN sockets (recommended default!)
215 *
216 * Due to the loopback this routine must not be called from hardirq context.
217 *
218 * Return:
219 * 0 on success
220 * -ENETDOWN when the selected interface is down
221 * -ENOBUFS on full driver queue (see net_xmit_errno())
222 * -ENOMEM when local loopback failed at calling skb_clone()
223 * -EPERM when trying to send on a non-CAN interface
224 * -EMSGSIZE CAN frame size is bigger than CAN interface MTU
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 canfd_frame *cfd = (struct canfd_frame *)skb->data;
231 int err = -EINVAL;
232
233 if (skb->len == CAN_MTU) {
234 skb->protocol = htons(ETH_P_CAN);
235 if (unlikely(cfd->len > CAN_MAX_DLEN))
236 goto inval_skb;
237 } else if (skb->len == CANFD_MTU) {
238 skb->protocol = htons(ETH_P_CANFD);
239 if (unlikely(cfd->len > CANFD_MAX_DLEN))
240 goto inval_skb;
241 } else
242 goto inval_skb;
243
244 /*
245 * Make sure the CAN frame can pass the selected CAN netdevice.
246 * As structs can_frame and canfd_frame are similar, we can provide
247 * CAN FD frames to legacy CAN drivers as long as the length is <= 8
248 */
249 if (unlikely(skb->len > skb->dev->mtu && cfd->len > CAN_MAX_DLEN)) {
250 err = -EMSGSIZE;
251 goto inval_skb;
252 }
253
254 if (unlikely(skb->dev->type != ARPHRD_CAN)) {
255 err = -EPERM;
256 goto inval_skb;
257 }
258
259 if (unlikely(!(skb->dev->flags & IFF_UP))) {
260 err = -ENETDOWN;
261 goto inval_skb;
262 }
263
264 skb->ip_summed = CHECKSUM_UNNECESSARY;
265
266 skb_reset_mac_header(skb);
267 skb_reset_network_header(skb);
268 skb_reset_transport_header(skb);
269
270 if (loop) {
271 /* local loopback of sent CAN frames */
272
273 /* indication for the CAN driver: do loopback */
274 skb->pkt_type = PACKET_LOOPBACK;
275
276 /*
277 * The reference to the originating sock may be required
278 * by the receiving socket to check whether the frame is
279 * its own. Example: can_raw sockopt CAN_RAW_RECV_OWN_MSGS
280 * Therefore we have to ensure that skb->sk remains the
281 * reference to the originating sock by restoring skb->sk
282 * after each skb_clone() or skb_orphan() usage.
283 */
284
285 if (!(skb->dev->flags & IFF_ECHO)) {
286 /*
287 * If the interface is not capable to do loopback
288 * itself, we do it here.
289 */
290 newskb = skb_clone(skb, GFP_ATOMIC);
291 if (!newskb) {
292 kfree_skb(skb);
293 return -ENOMEM;
294 }
295
296 can_skb_set_owner(newskb, skb->sk);
297 newskb->ip_summed = CHECKSUM_UNNECESSARY;
298 newskb->pkt_type = PACKET_BROADCAST;
299 }
300 } else {
301 /* indication for the CAN driver: no loopback required */
302 skb->pkt_type = PACKET_HOST;
303 }
304
305 /* send to netdevice */
306 err = dev_queue_xmit(skb);
307 if (err > 0)
308 err = net_xmit_errno(err);
309
310 if (err) {
311 kfree_skb(newskb);
312 return err;
313 }
314
315 if (newskb)
316 netif_rx_ni(newskb);
317
318 /* update statistics */
319 can_stats.tx_frames++;
320 can_stats.tx_frames_delta++;
321
322 return 0;
323
324inval_skb:
325 kfree_skb(skb);
326 return err;
327}
328EXPORT_SYMBOL(can_send);
329
330/*
331 * af_can rx path
332 */
333
334static struct dev_rcv_lists *find_dev_rcv_lists(struct net_device *dev)
335{
336 if (!dev)
337 return &can_rx_alldev_list;
338 else
339 return (struct dev_rcv_lists *)dev->ml_priv;
340}
341
342/**
343 * effhash - hash function for 29 bit CAN identifier reduction
344 * @can_id: 29 bit CAN identifier
345 *
346 * Description:
347 * To reduce the linear traversal in one linked list of _single_ EFF CAN
348 * frame subscriptions the 29 bit identifier is mapped to 10 bits.
349 * (see CAN_EFF_RCV_HASH_BITS definition)
350 *
351 * Return:
352 * Hash value from 0x000 - 0x3FF ( enforced by CAN_EFF_RCV_HASH_BITS mask )
353 */
354static unsigned int effhash(canid_t can_id)
355{
356 unsigned int hash;
357
358 hash = can_id;
359 hash ^= can_id >> CAN_EFF_RCV_HASH_BITS;
360 hash ^= can_id >> (2 * CAN_EFF_RCV_HASH_BITS);
361
362 return hash & ((1 << CAN_EFF_RCV_HASH_BITS) - 1);
363}
364
365/**
366 * find_rcv_list - determine optimal filterlist inside device filter struct
367 * @can_id: pointer to CAN identifier of a given can_filter
368 * @mask: pointer to CAN mask of a given can_filter
369 * @d: pointer to the device filter struct
370 *
371 * Description:
372 * Returns the optimal filterlist to reduce the filter handling in the
373 * receive path. This function is called by service functions that need
374 * to register or unregister a can_filter in the filter lists.
375 *
376 * A filter matches in general, when
377 *
378 * <received_can_id> & mask == can_id & mask
379 *
380 * so every bit set in the mask (even CAN_EFF_FLAG, CAN_RTR_FLAG) describe
381 * relevant bits for the filter.
382 *
383 * The filter can be inverted (CAN_INV_FILTER bit set in can_id) or it can
384 * filter for error messages (CAN_ERR_FLAG bit set in mask). For error msg
385 * frames there is a special filterlist and a special rx path filter handling.
386 *
387 * Return:
388 * Pointer to optimal filterlist for the given can_id/mask pair.
389 * Constistency checked mask.
390 * Reduced can_id to have a preprocessed filter compare value.
391 */
392static struct hlist_head *find_rcv_list(canid_t *can_id, canid_t *mask,
393 struct dev_rcv_lists *d)
394{
395 canid_t inv = *can_id & CAN_INV_FILTER; /* save flag before masking */
396
397 /* filter for error message frames in extra filterlist */
398 if (*mask & CAN_ERR_FLAG) {
399 /* clear CAN_ERR_FLAG in filter entry */
400 *mask &= CAN_ERR_MASK;
401 return &d->rx[RX_ERR];
402 }
403
404 /* with cleared CAN_ERR_FLAG we have a simple mask/value filterpair */
405
406#define CAN_EFF_RTR_FLAGS (CAN_EFF_FLAG | CAN_RTR_FLAG)
407
408 /* ensure valid values in can_mask for 'SFF only' frame filtering */
409 if ((*mask & CAN_EFF_FLAG) && !(*can_id & CAN_EFF_FLAG))
410 *mask &= (CAN_SFF_MASK | CAN_EFF_RTR_FLAGS);
411
412 /* reduce condition testing at receive time */
413 *can_id &= *mask;
414
415 /* inverse can_id/can_mask filter */
416 if (inv)
417 return &d->rx[RX_INV];
418
419 /* mask == 0 => no condition testing at receive time */
420 if (!(*mask))
421 return &d->rx[RX_ALL];
422
423 /* extra filterlists for the subscription of a single non-RTR can_id */
424 if (((*mask & CAN_EFF_RTR_FLAGS) == CAN_EFF_RTR_FLAGS) &&
425 !(*can_id & CAN_RTR_FLAG)) {
426
427 if (*can_id & CAN_EFF_FLAG) {
428 if (*mask == (CAN_EFF_MASK | CAN_EFF_RTR_FLAGS))
429 return &d->rx_eff[effhash(*can_id)];
430 } else {
431 if (*mask == (CAN_SFF_MASK | CAN_EFF_RTR_FLAGS))
432 return &d->rx_sff[*can_id];
433 }
434 }
435
436 /* default: filter via can_id/can_mask */
437 return &d->rx[RX_FIL];
438}
439
440/**
441 * can_rx_register - subscribe CAN frames from a specific interface
442 * @dev: pointer to netdevice (NULL => subcribe from 'all' CAN devices list)
443 * @can_id: CAN identifier (see description)
444 * @mask: CAN mask (see description)
445 * @func: callback function on filter match
446 * @data: returned parameter for callback function
447 * @ident: string for calling module identification
448 *
449 * Description:
450 * Invokes the callback function with the received sk_buff and the given
451 * parameter 'data' on a matching receive filter. A filter matches, when
452 *
453 * <received_can_id> & mask == can_id & mask
454 *
455 * The filter can be inverted (CAN_INV_FILTER bit set in can_id) or it can
456 * filter for error message frames (CAN_ERR_FLAG bit set in mask).
457 *
458 * The provided pointer to the sk_buff is guaranteed to be valid as long as
459 * the callback function is running. The callback function must *not* free
460 * the given sk_buff while processing it's task. When the given sk_buff is
461 * needed after the end of the callback function it must be cloned inside
462 * the callback function with skb_clone().
463 *
464 * Return:
465 * 0 on success
466 * -ENOMEM on missing cache mem to create subscription entry
467 * -ENODEV unknown device
468 */
469int can_rx_register(struct net_device *dev, canid_t can_id, canid_t mask,
470 void (*func)(struct sk_buff *, void *), void *data,
471 char *ident)
472{
473 struct receiver *r;
474 struct hlist_head *rl;
475 struct dev_rcv_lists *d;
476 int err = 0;
477
478 /* insert new receiver (dev,canid,mask) -> (func,data) */
479
480 if (dev && dev->type != ARPHRD_CAN)
481 return -ENODEV;
482
483 r = kmem_cache_alloc(rcv_cache, GFP_KERNEL);
484 if (!r)
485 return -ENOMEM;
486
487 spin_lock(&can_rcvlists_lock);
488
489 d = find_dev_rcv_lists(dev);
490 if (d) {
491 rl = find_rcv_list(&can_id, &mask, d);
492
493 r->can_id = can_id;
494 r->mask = mask;
495 r->matches = 0;
496 r->func = func;
497 r->data = data;
498 r->ident = ident;
499
500 hlist_add_head_rcu(&r->list, rl);
501 d->entries++;
502
503 can_pstats.rcv_entries++;
504 if (can_pstats.rcv_entries_max < can_pstats.rcv_entries)
505 can_pstats.rcv_entries_max = can_pstats.rcv_entries;
506 } else {
507 kmem_cache_free(rcv_cache, r);
508 err = -ENODEV;
509 }
510
511 spin_unlock(&can_rcvlists_lock);
512
513 return err;
514}
515EXPORT_SYMBOL(can_rx_register);
516
517/*
518 * can_rx_delete_receiver - rcu callback for single receiver entry removal
519 */
520static void can_rx_delete_receiver(struct rcu_head *rp)
521{
522 struct receiver *r = container_of(rp, struct receiver, rcu);
523
524 kmem_cache_free(rcv_cache, r);
525}
526
527/**
528 * can_rx_unregister - unsubscribe CAN frames from a specific interface
529 * @dev: pointer to netdevice (NULL => unsubscribe from 'all' CAN devices list)
530 * @can_id: CAN identifier
531 * @mask: CAN mask
532 * @func: callback function on filter match
533 * @data: returned parameter for callback function
534 *
535 * Description:
536 * Removes subscription entry depending on given (subscription) values.
537 */
538void can_rx_unregister(struct net_device *dev, canid_t can_id, canid_t mask,
539 void (*func)(struct sk_buff *, void *), void *data)
540{
541 struct receiver *r = NULL;
542 struct hlist_head *rl;
543 struct dev_rcv_lists *d;
544
545 if (dev && dev->type != ARPHRD_CAN)
546 return;
547
548 spin_lock(&can_rcvlists_lock);
549
550 d = find_dev_rcv_lists(dev);
551 if (!d) {
552 pr_err("BUG: receive list not found for "
553 "dev %s, id %03X, mask %03X\n",
554 DNAME(dev), can_id, mask);
555 goto out;
556 }
557
558 rl = find_rcv_list(&can_id, &mask, d);
559
560 /*
561 * Search the receiver list for the item to delete. This should
562 * exist, since no receiver may be unregistered that hasn't
563 * been registered before.
564 */
565
566 hlist_for_each_entry_rcu(r, rl, list) {
567 if (r->can_id == can_id && r->mask == mask &&
568 r->func == func && r->data == data)
569 break;
570 }
571
572 /*
573 * Check for bugs in CAN protocol implementations using af_can.c:
574 * 'r' will be NULL if no matching list item was found for removal.
575 */
576
577 if (!r) {
578 WARN(1, "BUG: receive list entry not found for dev %s, "
579 "id %03X, mask %03X\n", DNAME(dev), can_id, mask);
580 goto out;
581 }
582
583 hlist_del_rcu(&r->list);
584 d->entries--;
585
586 if (can_pstats.rcv_entries > 0)
587 can_pstats.rcv_entries--;
588
589 /* remove device structure requested by NETDEV_UNREGISTER */
590 if (d->remove_on_zero_entries && !d->entries) {
591 kfree(d);
592 dev->ml_priv = NULL;
593 }
594
595 out:
596 spin_unlock(&can_rcvlists_lock);
597
598 /* schedule the receiver item for deletion */
599 if (r)
600 call_rcu(&r->rcu, can_rx_delete_receiver);
601}
602EXPORT_SYMBOL(can_rx_unregister);
603
604static inline void deliver(struct sk_buff *skb, struct receiver *r)
605{
606 r->func(skb, r->data);
607 r->matches++;
608}
609
610static int can_rcv_filter(struct dev_rcv_lists *d, struct sk_buff *skb)
611{
612 struct receiver *r;
613 int matches = 0;
614 struct can_frame *cf = (struct can_frame *)skb->data;
615 canid_t can_id = cf->can_id;
616
617 if (d->entries == 0)
618 return 0;
619
620 if (can_id & CAN_ERR_FLAG) {
621 /* check for error message frame entries only */
622 hlist_for_each_entry_rcu(r, &d->rx[RX_ERR], list) {
623 if (can_id & r->mask) {
624 deliver(skb, r);
625 matches++;
626 }
627 }
628 return matches;
629 }
630
631 /* check for unfiltered entries */
632 hlist_for_each_entry_rcu(r, &d->rx[RX_ALL], list) {
633 deliver(skb, r);
634 matches++;
635 }
636
637 /* check for can_id/mask entries */
638 hlist_for_each_entry_rcu(r, &d->rx[RX_FIL], list) {
639 if ((can_id & r->mask) == r->can_id) {
640 deliver(skb, r);
641 matches++;
642 }
643 }
644
645 /* check for inverted can_id/mask entries */
646 hlist_for_each_entry_rcu(r, &d->rx[RX_INV], list) {
647 if ((can_id & r->mask) != r->can_id) {
648 deliver(skb, r);
649 matches++;
650 }
651 }
652
653 /* check filterlists for single non-RTR can_ids */
654 if (can_id & CAN_RTR_FLAG)
655 return matches;
656
657 if (can_id & CAN_EFF_FLAG) {
658 hlist_for_each_entry_rcu(r, &d->rx_eff[effhash(can_id)], list) {
659 if (r->can_id == can_id) {
660 deliver(skb, r);
661 matches++;
662 }
663 }
664 } else {
665 can_id &= CAN_SFF_MASK;
666 hlist_for_each_entry_rcu(r, &d->rx_sff[can_id], list) {
667 deliver(skb, r);
668 matches++;
669 }
670 }
671
672 return matches;
673}
674
675static void can_receive(struct sk_buff *skb, struct net_device *dev)
676{
677 struct dev_rcv_lists *d;
678 int matches;
679
680 /* update statistics */
681 can_stats.rx_frames++;
682 can_stats.rx_frames_delta++;
683
684 /* create non-zero unique skb identifier together with *skb */
685 while (!(can_skb_prv(skb)->skbcnt))
686 can_skb_prv(skb)->skbcnt = atomic_inc_return(&skbcounter);
687
688 rcu_read_lock();
689
690 /* deliver the packet to sockets listening on all devices */
691 matches = can_rcv_filter(&can_rx_alldev_list, skb);
692
693 /* find receive list for this device */
694 d = find_dev_rcv_lists(dev);
695 if (d)
696 matches += can_rcv_filter(d, skb);
697
698 rcu_read_unlock();
699
700 /* consume the skbuff allocated by the netdevice driver */
701 consume_skb(skb);
702
703 if (matches > 0) {
704 can_stats.matches++;
705 can_stats.matches_delta++;
706 }
707}
708
709static int can_rcv(struct sk_buff *skb, struct net_device *dev,
710 struct packet_type *pt, struct net_device *orig_dev)
711{
712 struct canfd_frame *cfd = (struct canfd_frame *)skb->data;
713
714 if (unlikely(!net_eq(dev_net(dev), &init_net)))
715 goto drop;
716
717 if (WARN_ONCE(dev->type != ARPHRD_CAN ||
718 skb->len != CAN_MTU ||
719 cfd->len > CAN_MAX_DLEN,
720 "PF_CAN: dropped non conform CAN skbuf: "
721 "dev type %d, len %d, datalen %d\n",
722 dev->type, skb->len, cfd->len))
723 goto drop;
724
725 can_receive(skb, dev);
726 return NET_RX_SUCCESS;
727
728drop:
729 kfree_skb(skb);
730 return NET_RX_DROP;
731}
732
733static int canfd_rcv(struct sk_buff *skb, struct net_device *dev,
734 struct packet_type *pt, struct net_device *orig_dev)
735{
736 struct canfd_frame *cfd = (struct canfd_frame *)skb->data;
737
738 if (unlikely(!net_eq(dev_net(dev), &init_net)))
739 goto drop;
740
741 if (WARN_ONCE(dev->type != ARPHRD_CAN ||
742 skb->len != CANFD_MTU ||
743 cfd->len > CANFD_MAX_DLEN,
744 "PF_CAN: dropped non conform CAN FD skbuf: "
745 "dev type %d, len %d, datalen %d\n",
746 dev->type, skb->len, cfd->len))
747 goto drop;
748
749 can_receive(skb, dev);
750 return NET_RX_SUCCESS;
751
752drop:
753 kfree_skb(skb);
754 return NET_RX_DROP;
755}
756
757/*
758 * af_can protocol functions
759 */
760
761/**
762 * can_proto_register - register CAN transport protocol
763 * @cp: pointer to CAN protocol structure
764 *
765 * Return:
766 * 0 on success
767 * -EINVAL invalid (out of range) protocol number
768 * -EBUSY protocol already in use
769 * -ENOBUF if proto_register() fails
770 */
771int can_proto_register(const struct can_proto *cp)
772{
773 int proto = cp->protocol;
774 int err = 0;
775
776 if (proto < 0 || proto >= CAN_NPROTO) {
777 pr_err("can: protocol number %d out of range\n", proto);
778 return -EINVAL;
779 }
780
781 err = proto_register(cp->prot, 0);
782 if (err < 0)
783 return err;
784
785 mutex_lock(&proto_tab_lock);
786
787 if (proto_tab[proto]) {
788 pr_err("can: protocol %d already registered\n", proto);
789 err = -EBUSY;
790 } else
791 RCU_INIT_POINTER(proto_tab[proto], cp);
792
793 mutex_unlock(&proto_tab_lock);
794
795 if (err < 0)
796 proto_unregister(cp->prot);
797
798 return err;
799}
800EXPORT_SYMBOL(can_proto_register);
801
802/**
803 * can_proto_unregister - unregister CAN transport protocol
804 * @cp: pointer to CAN protocol structure
805 */
806void can_proto_unregister(const struct can_proto *cp)
807{
808 int proto = cp->protocol;
809
810 mutex_lock(&proto_tab_lock);
811 BUG_ON(proto_tab[proto] != cp);
812 RCU_INIT_POINTER(proto_tab[proto], NULL);
813 mutex_unlock(&proto_tab_lock);
814
815 synchronize_rcu();
816
817 proto_unregister(cp->prot);
818}
819EXPORT_SYMBOL(can_proto_unregister);
820
821/*
822 * af_can notifier to create/remove CAN netdevice specific structs
823 */
824static int can_notifier(struct notifier_block *nb, unsigned long msg,
825 void *ptr)
826{
827 struct net_device *dev = netdev_notifier_info_to_dev(ptr);
828 struct dev_rcv_lists *d;
829
830 if (!net_eq(dev_net(dev), &init_net))
831 return NOTIFY_DONE;
832
833 if (dev->type != ARPHRD_CAN)
834 return NOTIFY_DONE;
835
836 switch (msg) {
837
838 case NETDEV_REGISTER:
839
840 /* create new dev_rcv_lists for this device */
841 d = kzalloc(sizeof(*d), GFP_KERNEL);
842 if (!d)
843 return NOTIFY_DONE;
844 BUG_ON(dev->ml_priv);
845 dev->ml_priv = d;
846
847 break;
848
849 case NETDEV_UNREGISTER:
850 spin_lock(&can_rcvlists_lock);
851
852 d = dev->ml_priv;
853 if (d) {
854 if (d->entries)
855 d->remove_on_zero_entries = 1;
856 else {
857 kfree(d);
858 dev->ml_priv = NULL;
859 }
860 } else
861 pr_err("can: notifier: receive list not found for dev "
862 "%s\n", dev->name);
863
864 spin_unlock(&can_rcvlists_lock);
865
866 break;
867 }
868
869 return NOTIFY_DONE;
870}
871
872/*
873 * af_can module init/exit functions
874 */
875
876static struct packet_type can_packet __read_mostly = {
877 .type = cpu_to_be16(ETH_P_CAN),
878 .func = can_rcv,
879};
880
881static struct packet_type canfd_packet __read_mostly = {
882 .type = cpu_to_be16(ETH_P_CANFD),
883 .func = canfd_rcv,
884};
885
886static const struct net_proto_family can_family_ops = {
887 .family = PF_CAN,
888 .create = can_create,
889 .owner = THIS_MODULE,
890};
891
892/* notifier block for netdevice event */
893static struct notifier_block can_netdev_notifier __read_mostly = {
894 .notifier_call = can_notifier,
895};
896
897static __init int can_init(void)
898{
899 /* check for correct padding to be able to use the structs similarly */
900 BUILD_BUG_ON(offsetof(struct can_frame, can_dlc) !=
901 offsetof(struct canfd_frame, len) ||
902 offsetof(struct can_frame, data) !=
903 offsetof(struct canfd_frame, data));
904
905 pr_info("can: controller area network core (" CAN_VERSION_STRING ")\n");
906
907 memset(&can_rx_alldev_list, 0, sizeof(can_rx_alldev_list));
908
909 rcv_cache = kmem_cache_create("can_receiver", sizeof(struct receiver),
910 0, 0, NULL);
911 if (!rcv_cache)
912 return -ENOMEM;
913
914 if (stats_timer) {
915 /* the statistics are updated every second (timer triggered) */
916 setup_timer(&can_stattimer, can_stat_update, 0);
917 mod_timer(&can_stattimer, round_jiffies(jiffies + HZ));
918 } else
919 can_stattimer.function = NULL;
920
921 can_init_proc();
922
923 /* protocol register */
924 sock_register(&can_family_ops);
925 register_netdevice_notifier(&can_netdev_notifier);
926 dev_add_pack(&can_packet);
927 dev_add_pack(&canfd_packet);
928
929 return 0;
930}
931
932static __exit void can_exit(void)
933{
934 struct net_device *dev;
935
936 if (stats_timer)
937 del_timer_sync(&can_stattimer);
938
939 can_remove_proc();
940
941 /* protocol unregister */
942 dev_remove_pack(&canfd_packet);
943 dev_remove_pack(&can_packet);
944 unregister_netdevice_notifier(&can_netdev_notifier);
945 sock_unregister(PF_CAN);
946
947 /* remove created dev_rcv_lists from still registered CAN devices */
948 rcu_read_lock();
949 for_each_netdev_rcu(&init_net, dev) {
950 if (dev->type == ARPHRD_CAN && dev->ml_priv) {
951
952 struct dev_rcv_lists *d = dev->ml_priv;
953
954 BUG_ON(d->entries);
955 kfree(d);
956 dev->ml_priv = NULL;
957 }
958 }
959 rcu_read_unlock();
960
961 rcu_barrier(); /* Wait for completion of call_rcu()'s */
962
963 kmem_cache_destroy(rcv_cache);
964}
965
966module_init(can_init);
967module_exit(can_exit);