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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// SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause)
2/* af_can.c - Protocol family CAN core module
3 * (used by different CAN protocol modules)
4 *
5 * Copyright (c) 2002-2017 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/can/can-ml.h>
62#include <linux/ratelimit.h>
63#include <net/net_namespace.h>
64#include <net/sock.h>
65
66#include "af_can.h"
67
68MODULE_DESCRIPTION("Controller Area Network PF_CAN core");
69MODULE_LICENSE("Dual BSD/GPL");
70MODULE_AUTHOR("Urs Thuermann <urs.thuermann@volkswagen.de>, "
71 "Oliver Hartkopp <oliver.hartkopp@volkswagen.de>");
72
73MODULE_ALIAS_NETPROTO(PF_CAN);
74
75static int stats_timer __read_mostly = 1;
76module_param(stats_timer, int, 0444);
77MODULE_PARM_DESC(stats_timer, "enable timer for statistics (default:on)");
78
79static struct kmem_cache *rcv_cache __read_mostly;
80
81/* table of registered CAN protocols */
82static const struct can_proto __rcu *proto_tab[CAN_NPROTO] __read_mostly;
83static DEFINE_MUTEX(proto_tab_lock);
84
85static atomic_t skbcounter = ATOMIC_INIT(0);
86
87/* af_can socket functions */
88
89void can_sock_destruct(struct sock *sk)
90{
91 skb_queue_purge(&sk->sk_receive_queue);
92 skb_queue_purge(&sk->sk_error_queue);
93}
94EXPORT_SYMBOL(can_sock_destruct);
95
96static const struct can_proto *can_get_proto(int protocol)
97{
98 const struct can_proto *cp;
99
100 rcu_read_lock();
101 cp = rcu_dereference(proto_tab[protocol]);
102 if (cp && !try_module_get(cp->prot->owner))
103 cp = NULL;
104 rcu_read_unlock();
105
106 return cp;
107}
108
109static inline void can_put_proto(const struct can_proto *cp)
110{
111 module_put(cp->prot->owner);
112}
113
114static int can_create(struct net *net, struct socket *sock, int protocol,
115 int kern)
116{
117 struct sock *sk;
118 const struct can_proto *cp;
119 int err = 0;
120
121 sock->state = SS_UNCONNECTED;
122
123 if (protocol < 0 || protocol >= CAN_NPROTO)
124 return -EINVAL;
125
126 cp = can_get_proto(protocol);
127
128#ifdef CONFIG_MODULES
129 if (!cp) {
130 /* try to load protocol module if kernel is modular */
131
132 err = request_module("can-proto-%d", protocol);
133
134 /* In case of error we only print a message but don't
135 * return the error code immediately. Below we will
136 * return -EPROTONOSUPPORT
137 */
138 if (err)
139 pr_err_ratelimited("can: request_module (can-proto-%d) failed.\n",
140 protocol);
141
142 cp = can_get_proto(protocol);
143 }
144#endif
145
146 /* check for available protocol and correct usage */
147
148 if (!cp)
149 return -EPROTONOSUPPORT;
150
151 if (cp->type != sock->type) {
152 err = -EPROTOTYPE;
153 goto errout;
154 }
155
156 sock->ops = cp->ops;
157
158 sk = sk_alloc(net, PF_CAN, GFP_KERNEL, cp->prot, kern);
159 if (!sk) {
160 err = -ENOMEM;
161 goto errout;
162 }
163
164 sock_init_data(sock, sk);
165 sk->sk_destruct = can_sock_destruct;
166
167 if (sk->sk_prot->init)
168 err = sk->sk_prot->init(sk);
169
170 if (err) {
171 /* release sk on errors */
172 sock_orphan(sk);
173 sock_put(sk);
174 }
175
176 errout:
177 can_put_proto(cp);
178 return err;
179}
180
181/* af_can tx path */
182
183/**
184 * can_send - transmit a CAN frame (optional with local loopback)
185 * @skb: pointer to socket buffer with CAN frame in data section
186 * @loop: loopback for listeners on local CAN sockets (recommended default!)
187 *
188 * Due to the loopback this routine must not be called from hardirq context.
189 *
190 * Return:
191 * 0 on success
192 * -ENETDOWN when the selected interface is down
193 * -ENOBUFS on full driver queue (see net_xmit_errno())
194 * -ENOMEM when local loopback failed at calling skb_clone()
195 * -EPERM when trying to send on a non-CAN interface
196 * -EMSGSIZE CAN frame size is bigger than CAN interface MTU
197 * -EINVAL when the skb->data does not contain a valid CAN frame
198 */
199int can_send(struct sk_buff *skb, int loop)
200{
201 struct sk_buff *newskb = NULL;
202 struct canfd_frame *cfd = (struct canfd_frame *)skb->data;
203 struct can_pkg_stats *pkg_stats = dev_net(skb->dev)->can.pkg_stats;
204 int err = -EINVAL;
205
206 if (skb->len == CAN_MTU) {
207 skb->protocol = htons(ETH_P_CAN);
208 if (unlikely(cfd->len > CAN_MAX_DLEN))
209 goto inval_skb;
210 } else if (skb->len == CANFD_MTU) {
211 skb->protocol = htons(ETH_P_CANFD);
212 if (unlikely(cfd->len > CANFD_MAX_DLEN))
213 goto inval_skb;
214 } else {
215 goto inval_skb;
216 }
217
218 /* Make sure the CAN frame can pass the selected CAN netdevice.
219 * As structs can_frame and canfd_frame are similar, we can provide
220 * CAN FD frames to legacy CAN drivers as long as the length is <= 8
221 */
222 if (unlikely(skb->len > skb->dev->mtu && cfd->len > CAN_MAX_DLEN)) {
223 err = -EMSGSIZE;
224 goto inval_skb;
225 }
226
227 if (unlikely(skb->dev->type != ARPHRD_CAN)) {
228 err = -EPERM;
229 goto inval_skb;
230 }
231
232 if (unlikely(!(skb->dev->flags & IFF_UP))) {
233 err = -ENETDOWN;
234 goto inval_skb;
235 }
236
237 skb->ip_summed = CHECKSUM_UNNECESSARY;
238
239 skb_reset_mac_header(skb);
240 skb_reset_network_header(skb);
241 skb_reset_transport_header(skb);
242
243 if (loop) {
244 /* local loopback of sent CAN frames */
245
246 /* indication for the CAN driver: do loopback */
247 skb->pkt_type = PACKET_LOOPBACK;
248
249 /* The reference to the originating sock may be required
250 * by the receiving socket to check whether the frame is
251 * its own. Example: can_raw sockopt CAN_RAW_RECV_OWN_MSGS
252 * Therefore we have to ensure that skb->sk remains the
253 * reference to the originating sock by restoring skb->sk
254 * after each skb_clone() or skb_orphan() usage.
255 */
256
257 if (!(skb->dev->flags & IFF_ECHO)) {
258 /* If the interface is not capable to do loopback
259 * itself, we do it here.
260 */
261 newskb = skb_clone(skb, GFP_ATOMIC);
262 if (!newskb) {
263 kfree_skb(skb);
264 return -ENOMEM;
265 }
266
267 can_skb_set_owner(newskb, skb->sk);
268 newskb->ip_summed = CHECKSUM_UNNECESSARY;
269 newskb->pkt_type = PACKET_BROADCAST;
270 }
271 } else {
272 /* indication for the CAN driver: no loopback required */
273 skb->pkt_type = PACKET_HOST;
274 }
275
276 /* send to netdevice */
277 err = dev_queue_xmit(skb);
278 if (err > 0)
279 err = net_xmit_errno(err);
280
281 if (err) {
282 kfree_skb(newskb);
283 return err;
284 }
285
286 if (newskb)
287 netif_rx_ni(newskb);
288
289 /* update statistics */
290 pkg_stats->tx_frames++;
291 pkg_stats->tx_frames_delta++;
292
293 return 0;
294
295inval_skb:
296 kfree_skb(skb);
297 return err;
298}
299EXPORT_SYMBOL(can_send);
300
301/* af_can rx path */
302
303static struct can_dev_rcv_lists *can_dev_rcv_lists_find(struct net *net,
304 struct net_device *dev)
305{
306 if (dev) {
307 struct can_ml_priv *can_ml = can_get_ml_priv(dev);
308 return &can_ml->dev_rcv_lists;
309 } else {
310 return net->can.rx_alldev_list;
311 }
312}
313
314/**
315 * effhash - hash function for 29 bit CAN identifier reduction
316 * @can_id: 29 bit CAN identifier
317 *
318 * Description:
319 * To reduce the linear traversal in one linked list of _single_ EFF CAN
320 * frame subscriptions the 29 bit identifier is mapped to 10 bits.
321 * (see CAN_EFF_RCV_HASH_BITS definition)
322 *
323 * Return:
324 * Hash value from 0x000 - 0x3FF ( enforced by CAN_EFF_RCV_HASH_BITS mask )
325 */
326static unsigned int effhash(canid_t can_id)
327{
328 unsigned int hash;
329
330 hash = can_id;
331 hash ^= can_id >> CAN_EFF_RCV_HASH_BITS;
332 hash ^= can_id >> (2 * CAN_EFF_RCV_HASH_BITS);
333
334 return hash & ((1 << CAN_EFF_RCV_HASH_BITS) - 1);
335}
336
337/**
338 * can_rcv_list_find - determine optimal filterlist inside device filter struct
339 * @can_id: pointer to CAN identifier of a given can_filter
340 * @mask: pointer to CAN mask of a given can_filter
341 * @dev_rcv_lists: pointer to the device filter struct
342 *
343 * Description:
344 * Returns the optimal filterlist to reduce the filter handling in the
345 * receive path. This function is called by service functions that need
346 * to register or unregister a can_filter in the filter lists.
347 *
348 * A filter matches in general, when
349 *
350 * <received_can_id> & mask == can_id & mask
351 *
352 * so every bit set in the mask (even CAN_EFF_FLAG, CAN_RTR_FLAG) describe
353 * relevant bits for the filter.
354 *
355 * The filter can be inverted (CAN_INV_FILTER bit set in can_id) or it can
356 * filter for error messages (CAN_ERR_FLAG bit set in mask). For error msg
357 * frames there is a special filterlist and a special rx path filter handling.
358 *
359 * Return:
360 * Pointer to optimal filterlist for the given can_id/mask pair.
361 * Consistency checked mask.
362 * Reduced can_id to have a preprocessed filter compare value.
363 */
364static struct hlist_head *can_rcv_list_find(canid_t *can_id, canid_t *mask,
365 struct can_dev_rcv_lists *dev_rcv_lists)
366{
367 canid_t inv = *can_id & CAN_INV_FILTER; /* save flag before masking */
368
369 /* filter for error message frames in extra filterlist */
370 if (*mask & CAN_ERR_FLAG) {
371 /* clear CAN_ERR_FLAG in filter entry */
372 *mask &= CAN_ERR_MASK;
373 return &dev_rcv_lists->rx[RX_ERR];
374 }
375
376 /* with cleared CAN_ERR_FLAG we have a simple mask/value filterpair */
377
378#define CAN_EFF_RTR_FLAGS (CAN_EFF_FLAG | CAN_RTR_FLAG)
379
380 /* ensure valid values in can_mask for 'SFF only' frame filtering */
381 if ((*mask & CAN_EFF_FLAG) && !(*can_id & CAN_EFF_FLAG))
382 *mask &= (CAN_SFF_MASK | CAN_EFF_RTR_FLAGS);
383
384 /* reduce condition testing at receive time */
385 *can_id &= *mask;
386
387 /* inverse can_id/can_mask filter */
388 if (inv)
389 return &dev_rcv_lists->rx[RX_INV];
390
391 /* mask == 0 => no condition testing at receive time */
392 if (!(*mask))
393 return &dev_rcv_lists->rx[RX_ALL];
394
395 /* extra filterlists for the subscription of a single non-RTR can_id */
396 if (((*mask & CAN_EFF_RTR_FLAGS) == CAN_EFF_RTR_FLAGS) &&
397 !(*can_id & CAN_RTR_FLAG)) {
398 if (*can_id & CAN_EFF_FLAG) {
399 if (*mask == (CAN_EFF_MASK | CAN_EFF_RTR_FLAGS))
400 return &dev_rcv_lists->rx_eff[effhash(*can_id)];
401 } else {
402 if (*mask == (CAN_SFF_MASK | CAN_EFF_RTR_FLAGS))
403 return &dev_rcv_lists->rx_sff[*can_id];
404 }
405 }
406
407 /* default: filter via can_id/can_mask */
408 return &dev_rcv_lists->rx[RX_FIL];
409}
410
411/**
412 * can_rx_register - subscribe CAN frames from a specific interface
413 * @net: the applicable net namespace
414 * @dev: pointer to netdevice (NULL => subscribe from 'all' CAN devices list)
415 * @can_id: CAN identifier (see description)
416 * @mask: CAN mask (see description)
417 * @func: callback function on filter match
418 * @data: returned parameter for callback function
419 * @ident: string for calling module identification
420 * @sk: socket pointer (might be NULL)
421 *
422 * Description:
423 * Invokes the callback function with the received sk_buff and the given
424 * parameter 'data' on a matching receive filter. A filter matches, when
425 *
426 * <received_can_id> & mask == can_id & mask
427 *
428 * The filter can be inverted (CAN_INV_FILTER bit set in can_id) or it can
429 * filter for error message frames (CAN_ERR_FLAG bit set in mask).
430 *
431 * The provided pointer to the sk_buff is guaranteed to be valid as long as
432 * the callback function is running. The callback function must *not* free
433 * the given sk_buff while processing it's task. When the given sk_buff is
434 * needed after the end of the callback function it must be cloned inside
435 * the callback function with skb_clone().
436 *
437 * Return:
438 * 0 on success
439 * -ENOMEM on missing cache mem to create subscription entry
440 * -ENODEV unknown device
441 */
442int can_rx_register(struct net *net, struct net_device *dev, canid_t can_id,
443 canid_t mask, void (*func)(struct sk_buff *, void *),
444 void *data, char *ident, struct sock *sk)
445{
446 struct receiver *rcv;
447 struct hlist_head *rcv_list;
448 struct can_dev_rcv_lists *dev_rcv_lists;
449 struct can_rcv_lists_stats *rcv_lists_stats = net->can.rcv_lists_stats;
450 int err = 0;
451
452 /* insert new receiver (dev,canid,mask) -> (func,data) */
453
454 if (dev && dev->type != ARPHRD_CAN)
455 return -ENODEV;
456
457 if (dev && !net_eq(net, dev_net(dev)))
458 return -ENODEV;
459
460 rcv = kmem_cache_alloc(rcv_cache, GFP_KERNEL);
461 if (!rcv)
462 return -ENOMEM;
463
464 spin_lock_bh(&net->can.rcvlists_lock);
465
466 dev_rcv_lists = can_dev_rcv_lists_find(net, dev);
467 rcv_list = can_rcv_list_find(&can_id, &mask, dev_rcv_lists);
468
469 rcv->can_id = can_id;
470 rcv->mask = mask;
471 rcv->matches = 0;
472 rcv->func = func;
473 rcv->data = data;
474 rcv->ident = ident;
475 rcv->sk = sk;
476
477 hlist_add_head_rcu(&rcv->list, rcv_list);
478 dev_rcv_lists->entries++;
479
480 rcv_lists_stats->rcv_entries++;
481 rcv_lists_stats->rcv_entries_max = max(rcv_lists_stats->rcv_entries_max,
482 rcv_lists_stats->rcv_entries);
483 spin_unlock_bh(&net->can.rcvlists_lock);
484
485 return err;
486}
487EXPORT_SYMBOL(can_rx_register);
488
489/* can_rx_delete_receiver - rcu callback for single receiver entry removal */
490static void can_rx_delete_receiver(struct rcu_head *rp)
491{
492 struct receiver *rcv = container_of(rp, struct receiver, rcu);
493 struct sock *sk = rcv->sk;
494
495 kmem_cache_free(rcv_cache, rcv);
496 if (sk)
497 sock_put(sk);
498}
499
500/**
501 * can_rx_unregister - unsubscribe CAN frames from a specific interface
502 * @net: the applicable net namespace
503 * @dev: pointer to netdevice (NULL => unsubscribe from 'all' CAN devices list)
504 * @can_id: CAN identifier
505 * @mask: CAN mask
506 * @func: callback function on filter match
507 * @data: returned parameter for callback function
508 *
509 * Description:
510 * Removes subscription entry depending on given (subscription) values.
511 */
512void can_rx_unregister(struct net *net, struct net_device *dev, canid_t can_id,
513 canid_t mask, void (*func)(struct sk_buff *, void *),
514 void *data)
515{
516 struct receiver *rcv = NULL;
517 struct hlist_head *rcv_list;
518 struct can_rcv_lists_stats *rcv_lists_stats = net->can.rcv_lists_stats;
519 struct can_dev_rcv_lists *dev_rcv_lists;
520
521 if (dev && dev->type != ARPHRD_CAN)
522 return;
523
524 if (dev && !net_eq(net, dev_net(dev)))
525 return;
526
527 spin_lock_bh(&net->can.rcvlists_lock);
528
529 dev_rcv_lists = can_dev_rcv_lists_find(net, dev);
530 rcv_list = can_rcv_list_find(&can_id, &mask, dev_rcv_lists);
531
532 /* Search the receiver list for the item to delete. This should
533 * exist, since no receiver may be unregistered that hasn't
534 * been registered before.
535 */
536 hlist_for_each_entry_rcu(rcv, rcv_list, list) {
537 if (rcv->can_id == can_id && rcv->mask == mask &&
538 rcv->func == func && rcv->data == data)
539 break;
540 }
541
542 /* Check for bugs in CAN protocol implementations using af_can.c:
543 * 'rcv' will be NULL if no matching list item was found for removal.
544 * As this case may potentially happen when closing a socket while
545 * the notifier for removing the CAN netdev is running we just print
546 * a warning here.
547 */
548 if (!rcv) {
549 pr_warn("can: receive list entry not found for dev %s, id %03X, mask %03X\n",
550 DNAME(dev), can_id, mask);
551 goto out;
552 }
553
554 hlist_del_rcu(&rcv->list);
555 dev_rcv_lists->entries--;
556
557 if (rcv_lists_stats->rcv_entries > 0)
558 rcv_lists_stats->rcv_entries--;
559
560 out:
561 spin_unlock_bh(&net->can.rcvlists_lock);
562
563 /* schedule the receiver item for deletion */
564 if (rcv) {
565 if (rcv->sk)
566 sock_hold(rcv->sk);
567 call_rcu(&rcv->rcu, can_rx_delete_receiver);
568 }
569}
570EXPORT_SYMBOL(can_rx_unregister);
571
572static inline void deliver(struct sk_buff *skb, struct receiver *rcv)
573{
574 rcv->func(skb, rcv->data);
575 rcv->matches++;
576}
577
578static int can_rcv_filter(struct can_dev_rcv_lists *dev_rcv_lists, struct sk_buff *skb)
579{
580 struct receiver *rcv;
581 int matches = 0;
582 struct can_frame *cf = (struct can_frame *)skb->data;
583 canid_t can_id = cf->can_id;
584
585 if (dev_rcv_lists->entries == 0)
586 return 0;
587
588 if (can_id & CAN_ERR_FLAG) {
589 /* check for error message frame entries only */
590 hlist_for_each_entry_rcu(rcv, &dev_rcv_lists->rx[RX_ERR], list) {
591 if (can_id & rcv->mask) {
592 deliver(skb, rcv);
593 matches++;
594 }
595 }
596 return matches;
597 }
598
599 /* check for unfiltered entries */
600 hlist_for_each_entry_rcu(rcv, &dev_rcv_lists->rx[RX_ALL], list) {
601 deliver(skb, rcv);
602 matches++;
603 }
604
605 /* check for can_id/mask entries */
606 hlist_for_each_entry_rcu(rcv, &dev_rcv_lists->rx[RX_FIL], list) {
607 if ((can_id & rcv->mask) == rcv->can_id) {
608 deliver(skb, rcv);
609 matches++;
610 }
611 }
612
613 /* check for inverted can_id/mask entries */
614 hlist_for_each_entry_rcu(rcv, &dev_rcv_lists->rx[RX_INV], list) {
615 if ((can_id & rcv->mask) != rcv->can_id) {
616 deliver(skb, rcv);
617 matches++;
618 }
619 }
620
621 /* check filterlists for single non-RTR can_ids */
622 if (can_id & CAN_RTR_FLAG)
623 return matches;
624
625 if (can_id & CAN_EFF_FLAG) {
626 hlist_for_each_entry_rcu(rcv, &dev_rcv_lists->rx_eff[effhash(can_id)], list) {
627 if (rcv->can_id == can_id) {
628 deliver(skb, rcv);
629 matches++;
630 }
631 }
632 } else {
633 can_id &= CAN_SFF_MASK;
634 hlist_for_each_entry_rcu(rcv, &dev_rcv_lists->rx_sff[can_id], list) {
635 deliver(skb, rcv);
636 matches++;
637 }
638 }
639
640 return matches;
641}
642
643static void can_receive(struct sk_buff *skb, struct net_device *dev)
644{
645 struct can_dev_rcv_lists *dev_rcv_lists;
646 struct net *net = dev_net(dev);
647 struct can_pkg_stats *pkg_stats = net->can.pkg_stats;
648 int matches;
649
650 /* update statistics */
651 pkg_stats->rx_frames++;
652 pkg_stats->rx_frames_delta++;
653
654 /* create non-zero unique skb identifier together with *skb */
655 while (!(can_skb_prv(skb)->skbcnt))
656 can_skb_prv(skb)->skbcnt = atomic_inc_return(&skbcounter);
657
658 rcu_read_lock();
659
660 /* deliver the packet to sockets listening on all devices */
661 matches = can_rcv_filter(net->can.rx_alldev_list, skb);
662
663 /* find receive list for this device */
664 dev_rcv_lists = can_dev_rcv_lists_find(net, dev);
665 matches += can_rcv_filter(dev_rcv_lists, skb);
666
667 rcu_read_unlock();
668
669 /* consume the skbuff allocated by the netdevice driver */
670 consume_skb(skb);
671
672 if (matches > 0) {
673 pkg_stats->matches++;
674 pkg_stats->matches_delta++;
675 }
676}
677
678static int can_rcv(struct sk_buff *skb, struct net_device *dev,
679 struct packet_type *pt, struct net_device *orig_dev)
680{
681 struct canfd_frame *cfd = (struct canfd_frame *)skb->data;
682
683 if (unlikely(dev->type != ARPHRD_CAN || skb->len != CAN_MTU)) {
684 pr_warn_once("PF_CAN: dropped non conform CAN skbuff: dev type %d, len %d\n",
685 dev->type, skb->len);
686 goto free_skb;
687 }
688
689 /* This check is made separately since cfd->len would be uninitialized if skb->len = 0. */
690 if (unlikely(cfd->len > CAN_MAX_DLEN)) {
691 pr_warn_once("PF_CAN: dropped non conform CAN skbuff: dev type %d, len %d, datalen %d\n",
692 dev->type, skb->len, cfd->len);
693 goto free_skb;
694 }
695
696 can_receive(skb, dev);
697 return NET_RX_SUCCESS;
698
699free_skb:
700 kfree_skb(skb);
701 return NET_RX_DROP;
702}
703
704static int canfd_rcv(struct sk_buff *skb, struct net_device *dev,
705 struct packet_type *pt, struct net_device *orig_dev)
706{
707 struct canfd_frame *cfd = (struct canfd_frame *)skb->data;
708
709 if (unlikely(dev->type != ARPHRD_CAN || skb->len != CANFD_MTU)) {
710 pr_warn_once("PF_CAN: dropped non conform CAN FD skbuff: dev type %d, len %d\n",
711 dev->type, skb->len);
712 goto free_skb;
713 }
714
715 /* This check is made separately since cfd->len would be uninitialized if skb->len = 0. */
716 if (unlikely(cfd->len > CANFD_MAX_DLEN)) {
717 pr_warn_once("PF_CAN: dropped non conform CAN FD skbuff: dev type %d, len %d, datalen %d\n",
718 dev->type, skb->len, cfd->len);
719 goto free_skb;
720 }
721
722 can_receive(skb, dev);
723 return NET_RX_SUCCESS;
724
725free_skb:
726 kfree_skb(skb);
727 return NET_RX_DROP;
728}
729
730/* af_can protocol functions */
731
732/**
733 * can_proto_register - register CAN transport protocol
734 * @cp: pointer to CAN protocol structure
735 *
736 * Return:
737 * 0 on success
738 * -EINVAL invalid (out of range) protocol number
739 * -EBUSY protocol already in use
740 * -ENOBUF if proto_register() fails
741 */
742int can_proto_register(const struct can_proto *cp)
743{
744 int proto = cp->protocol;
745 int err = 0;
746
747 if (proto < 0 || proto >= CAN_NPROTO) {
748 pr_err("can: protocol number %d out of range\n", proto);
749 return -EINVAL;
750 }
751
752 err = proto_register(cp->prot, 0);
753 if (err < 0)
754 return err;
755
756 mutex_lock(&proto_tab_lock);
757
758 if (rcu_access_pointer(proto_tab[proto])) {
759 pr_err("can: protocol %d already registered\n", proto);
760 err = -EBUSY;
761 } else {
762 RCU_INIT_POINTER(proto_tab[proto], cp);
763 }
764
765 mutex_unlock(&proto_tab_lock);
766
767 if (err < 0)
768 proto_unregister(cp->prot);
769
770 return err;
771}
772EXPORT_SYMBOL(can_proto_register);
773
774/**
775 * can_proto_unregister - unregister CAN transport protocol
776 * @cp: pointer to CAN protocol structure
777 */
778void can_proto_unregister(const struct can_proto *cp)
779{
780 int proto = cp->protocol;
781
782 mutex_lock(&proto_tab_lock);
783 BUG_ON(rcu_access_pointer(proto_tab[proto]) != cp);
784 RCU_INIT_POINTER(proto_tab[proto], NULL);
785 mutex_unlock(&proto_tab_lock);
786
787 synchronize_rcu();
788
789 proto_unregister(cp->prot);
790}
791EXPORT_SYMBOL(can_proto_unregister);
792
793static int can_pernet_init(struct net *net)
794{
795 spin_lock_init(&net->can.rcvlists_lock);
796 net->can.rx_alldev_list =
797 kzalloc(sizeof(*net->can.rx_alldev_list), GFP_KERNEL);
798 if (!net->can.rx_alldev_list)
799 goto out;
800 net->can.pkg_stats = kzalloc(sizeof(*net->can.pkg_stats), GFP_KERNEL);
801 if (!net->can.pkg_stats)
802 goto out_free_rx_alldev_list;
803 net->can.rcv_lists_stats = kzalloc(sizeof(*net->can.rcv_lists_stats), GFP_KERNEL);
804 if (!net->can.rcv_lists_stats)
805 goto out_free_pkg_stats;
806
807 if (IS_ENABLED(CONFIG_PROC_FS)) {
808 /* the statistics are updated every second (timer triggered) */
809 if (stats_timer) {
810 timer_setup(&net->can.stattimer, can_stat_update,
811 0);
812 mod_timer(&net->can.stattimer,
813 round_jiffies(jiffies + HZ));
814 }
815 net->can.pkg_stats->jiffies_init = jiffies;
816 can_init_proc(net);
817 }
818
819 return 0;
820
821 out_free_pkg_stats:
822 kfree(net->can.pkg_stats);
823 out_free_rx_alldev_list:
824 kfree(net->can.rx_alldev_list);
825 out:
826 return -ENOMEM;
827}
828
829static void can_pernet_exit(struct net *net)
830{
831 if (IS_ENABLED(CONFIG_PROC_FS)) {
832 can_remove_proc(net);
833 if (stats_timer)
834 del_timer_sync(&net->can.stattimer);
835 }
836
837 kfree(net->can.rx_alldev_list);
838 kfree(net->can.pkg_stats);
839 kfree(net->can.rcv_lists_stats);
840}
841
842/* af_can module init/exit functions */
843
844static struct packet_type can_packet __read_mostly = {
845 .type = cpu_to_be16(ETH_P_CAN),
846 .func = can_rcv,
847};
848
849static struct packet_type canfd_packet __read_mostly = {
850 .type = cpu_to_be16(ETH_P_CANFD),
851 .func = canfd_rcv,
852};
853
854static const struct net_proto_family can_family_ops = {
855 .family = PF_CAN,
856 .create = can_create,
857 .owner = THIS_MODULE,
858};
859
860static struct pernet_operations can_pernet_ops __read_mostly = {
861 .init = can_pernet_init,
862 .exit = can_pernet_exit,
863};
864
865static __init int can_init(void)
866{
867 int err;
868
869 /* check for correct padding to be able to use the structs similarly */
870 BUILD_BUG_ON(offsetof(struct can_frame, len) !=
871 offsetof(struct canfd_frame, len) ||
872 offsetof(struct can_frame, data) !=
873 offsetof(struct canfd_frame, data));
874
875 pr_info("can: controller area network core\n");
876
877 rcv_cache = kmem_cache_create("can_receiver", sizeof(struct receiver),
878 0, 0, NULL);
879 if (!rcv_cache)
880 return -ENOMEM;
881
882 err = register_pernet_subsys(&can_pernet_ops);
883 if (err)
884 goto out_pernet;
885
886 /* protocol register */
887 err = sock_register(&can_family_ops);
888 if (err)
889 goto out_sock;
890
891 dev_add_pack(&can_packet);
892 dev_add_pack(&canfd_packet);
893
894 return 0;
895
896out_sock:
897 unregister_pernet_subsys(&can_pernet_ops);
898out_pernet:
899 kmem_cache_destroy(rcv_cache);
900
901 return err;
902}
903
904static __exit void can_exit(void)
905{
906 /* protocol unregister */
907 dev_remove_pack(&canfd_packet);
908 dev_remove_pack(&can_packet);
909 sock_unregister(PF_CAN);
910
911 unregister_pernet_subsys(&can_pernet_ops);
912
913 rcu_barrier(); /* Wait for completion of call_rcu()'s */
914
915 kmem_cache_destroy(rcv_cache);
916}
917
918module_init(can_init);
919module_exit(can_exit);