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
68 MODULE_DESCRIPTION("Controller Area Network PF_CAN core");
69 MODULE_LICENSE("Dual BSD/GPL");
70 MODULE_AUTHOR("Urs Thuermann <urs.thuermann@volkswagen.de>, "
71 "Oliver Hartkopp <oliver.hartkopp@volkswagen.de>");
72
73 MODULE_ALIAS_NETPROTO(PF_CAN);
74
75 static int stats_timer __read_mostly = 1;
76 module_param(stats_timer, int, 0444);
77 MODULE_PARM_DESC(stats_timer, "enable timer for statistics (default:on)");
78
79 static struct kmem_cache *rcv_cache __read_mostly;
80
81 /* table of registered CAN protocols */
82 static const struct can_proto __rcu *proto_tab[CAN_NPROTO] __read_mostly;
83 static DEFINE_MUTEX(proto_tab_lock);
84
85 static atomic_t skbcounter = ATOMIC_INIT(0);
86
87 /* af_can socket functions */
88
89 void can_sock_destruct(struct sock *sk)
90 {
91 skb_queue_purge(&sk->sk_receive_queue);
92 skb_queue_purge(&sk->sk_error_queue);
93 }
94 EXPORT_SYMBOL(can_sock_destruct);
95
96 static 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
109 static inline void can_put_proto(const struct can_proto *cp)
110 {
111 module_put(cp->prot->owner);
112 }
113
114 static 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 */
199 int can_send(struct sk_buff *skb, int loop)
200 {
201 struct sk_buff *newskb = NULL;
202 struct can_pkg_stats *pkg_stats = dev_net(skb->dev)->can.pkg_stats;
203 int err = -EINVAL;
204
205 if (can_is_canxl_skb(skb)) {
206 skb->protocol = htons(ETH_P_CANXL);
207 } else if (can_is_can_skb(skb)) {
208 skb->protocol = htons(ETH_P_CAN);
209 } else if (can_is_canfd_skb(skb)) {
210 struct canfd_frame *cfd = (struct canfd_frame *)skb->data;
211
212 skb->protocol = htons(ETH_P_CANFD);
213
214 /* set CAN FD flag for CAN FD frames by default */
215 cfd->flags |= CANFD_FDF;
216 } else {
217 goto inval_skb;
218 }
219
220 /* Make sure the CAN frame can pass the selected CAN netdevice. */
221 if (unlikely(skb->len > skb->dev->mtu)) {
222 err = -EMSGSIZE;
223 goto inval_skb;
224 }
225
226 if (unlikely(skb->dev->type != ARPHRD_CAN)) {
227 err = -EPERM;
228 goto inval_skb;
229 }
230
231 if (unlikely(!(skb->dev->flags & IFF_UP))) {
232 err = -ENETDOWN;
233 goto inval_skb;
234 }
235
236 skb->ip_summed = CHECKSUM_UNNECESSARY;
237
238 skb_reset_mac_header(skb);
239 skb_reset_network_header(skb);
240 skb_reset_transport_header(skb);
241
242 if (loop) {
243 /* local loopback of sent CAN frames */
244
245 /* indication for the CAN driver: do loopback */
246 skb->pkt_type = PACKET_LOOPBACK;
247
248 /* The reference to the originating sock may be required
249 * by the receiving socket to check whether the frame is
250 * its own. Example: can_raw sockopt CAN_RAW_RECV_OWN_MSGS
251 * Therefore we have to ensure that skb->sk remains the
252 * reference to the originating sock by restoring skb->sk
253 * after each skb_clone() or skb_orphan() usage.
254 */
255
256 if (!(skb->dev->flags & IFF_ECHO)) {
257 /* If the interface is not capable to do loopback
258 * itself, we do it here.
259 */
260 newskb = skb_clone(skb, GFP_ATOMIC);
261 if (!newskb) {
262 kfree_skb(skb);
263 return -ENOMEM;
264 }
265
266 can_skb_set_owner(newskb, skb->sk);
267 newskb->ip_summed = CHECKSUM_UNNECESSARY;
268 newskb->pkt_type = PACKET_BROADCAST;
269 }
270 } else {
271 /* indication for the CAN driver: no loopback required */
272 skb->pkt_type = PACKET_HOST;
273 }
274
275 /* send to netdevice */
276 err = dev_queue_xmit(skb);
277 if (err > 0)
278 err = net_xmit_errno(err);
279
280 if (err) {
281 kfree_skb(newskb);
282 return err;
283 }
284
285 if (newskb)
286 netif_rx(newskb);
287
288 /* update statistics */
289 pkg_stats->tx_frames++;
290 pkg_stats->tx_frames_delta++;
291
292 return 0;
293
294 inval_skb:
295 kfree_skb(skb);
296 return err;
297 }
298 EXPORT_SYMBOL(can_send);
299
300 /* af_can rx path */
301
302 static struct can_dev_rcv_lists *can_dev_rcv_lists_find(struct net *net,
303 struct net_device *dev)
304 {
305 if (dev) {
306 struct can_ml_priv *can_ml = can_get_ml_priv(dev);
307 return &can_ml->dev_rcv_lists;
308 } else {
309 return net->can.rx_alldev_list;
310 }
311 }
312
313 /**
314 * effhash - hash function for 29 bit CAN identifier reduction
315 * @can_id: 29 bit CAN identifier
316 *
317 * Description:
318 * To reduce the linear traversal in one linked list of _single_ EFF CAN
319 * frame subscriptions the 29 bit identifier is mapped to 10 bits.
320 * (see CAN_EFF_RCV_HASH_BITS definition)
321 *
322 * Return:
323 * Hash value from 0x000 - 0x3FF ( enforced by CAN_EFF_RCV_HASH_BITS mask )
324 */
325 static unsigned int effhash(canid_t can_id)
326 {
327 unsigned int hash;
328
329 hash = can_id;
330 hash ^= can_id >> CAN_EFF_RCV_HASH_BITS;
331 hash ^= can_id >> (2 * CAN_EFF_RCV_HASH_BITS);
332
333 return hash & ((1 << CAN_EFF_RCV_HASH_BITS) - 1);
334 }
335
336 /**
337 * can_rcv_list_find - determine optimal filterlist inside device filter struct
338 * @can_id: pointer to CAN identifier of a given can_filter
339 * @mask: pointer to CAN mask of a given can_filter
340 * @dev_rcv_lists: pointer to the device filter struct
341 *
342 * Description:
343 * Returns the optimal filterlist to reduce the filter handling in the
344 * receive path. This function is called by service functions that need
345 * to register or unregister a can_filter in the filter lists.
346 *
347 * A filter matches in general, when
348 *
349 * <received_can_id> & mask == can_id & mask
350 *
351 * so every bit set in the mask (even CAN_EFF_FLAG, CAN_RTR_FLAG) describe
352 * relevant bits for the filter.
353 *
354 * The filter can be inverted (CAN_INV_FILTER bit set in can_id) or it can
355 * filter for error messages (CAN_ERR_FLAG bit set in mask). For error msg
356 * frames there is a special filterlist and a special rx path filter handling.
357 *
358 * Return:
359 * Pointer to optimal filterlist for the given can_id/mask pair.
360 * Consistency checked mask.
361 * Reduced can_id to have a preprocessed filter compare value.
362 */
363 static struct hlist_head *can_rcv_list_find(canid_t *can_id, canid_t *mask,
364 struct can_dev_rcv_lists *dev_rcv_lists)
365 {
366 canid_t inv = *can_id & CAN_INV_FILTER; /* save flag before masking */
367
368 /* filter for error message frames in extra filterlist */
369 if (*mask & CAN_ERR_FLAG) {
370 /* clear CAN_ERR_FLAG in filter entry */
371 *mask &= CAN_ERR_MASK;
372 return &dev_rcv_lists->rx[RX_ERR];
373 }
374
375 /* with cleared CAN_ERR_FLAG we have a simple mask/value filterpair */
376
377 #define CAN_EFF_RTR_FLAGS (CAN_EFF_FLAG | CAN_RTR_FLAG)
378
379 /* ensure valid values in can_mask for 'SFF only' frame filtering */
380 if ((*mask & CAN_EFF_FLAG) && !(*can_id & CAN_EFF_FLAG))
381 *mask &= (CAN_SFF_MASK | CAN_EFF_RTR_FLAGS);
382
383 /* reduce condition testing at receive time */
384 *can_id &= *mask;
385
386 /* inverse can_id/can_mask filter */
387 if (inv)
388 return &dev_rcv_lists->rx[RX_INV];
389
390 /* mask == 0 => no condition testing at receive time */
391 if (!(*mask))
392 return &dev_rcv_lists->rx[RX_ALL];
393
394 /* extra filterlists for the subscription of a single non-RTR can_id */
395 if (((*mask & CAN_EFF_RTR_FLAGS) == CAN_EFF_RTR_FLAGS) &&
396 !(*can_id & CAN_RTR_FLAG)) {
397 if (*can_id & CAN_EFF_FLAG) {
398 if (*mask == (CAN_EFF_MASK | CAN_EFF_RTR_FLAGS))
399 return &dev_rcv_lists->rx_eff[effhash(*can_id)];
400 } else {
401 if (*mask == (CAN_SFF_MASK | CAN_EFF_RTR_FLAGS))
402 return &dev_rcv_lists->rx_sff[*can_id];
403 }
404 }
405
406 /* default: filter via can_id/can_mask */
407 return &dev_rcv_lists->rx[RX_FIL];
408 }
409
410 /**
411 * can_rx_register - subscribe CAN frames from a specific interface
412 * @net: the applicable net namespace
413 * @dev: pointer to netdevice (NULL => subscribe from 'all' CAN devices list)
414 * @can_id: CAN identifier (see description)
415 * @mask: CAN mask (see description)
416 * @func: callback function on filter match
417 * @data: returned parameter for callback function
418 * @ident: string for calling module identification
419 * @sk: socket pointer (might be NULL)
420 *
421 * Description:
422 * Invokes the callback function with the received sk_buff and the given
423 * parameter 'data' on a matching receive filter. A filter matches, when
424 *
425 * <received_can_id> & mask == can_id & mask
426 *
427 * The filter can be inverted (CAN_INV_FILTER bit set in can_id) or it can
428 * filter for error message frames (CAN_ERR_FLAG bit set in mask).
429 *
430 * The provided pointer to the sk_buff is guaranteed to be valid as long as
431 * the callback function is running. The callback function must *not* free
432 * the given sk_buff while processing it's task. When the given sk_buff is
433 * needed after the end of the callback function it must be cloned inside
434 * the callback function with skb_clone().
435 *
436 * Return:
437 * 0 on success
438 * -ENOMEM on missing cache mem to create subscription entry
439 * -ENODEV unknown device
440 */
441 int can_rx_register(struct net *net, struct net_device *dev, canid_t can_id,
442 canid_t mask, void (*func)(struct sk_buff *, void *),
443 void *data, char *ident, struct sock *sk)
444 {
445 struct receiver *rcv;
446 struct hlist_head *rcv_list;
447 struct can_dev_rcv_lists *dev_rcv_lists;
448 struct can_rcv_lists_stats *rcv_lists_stats = net->can.rcv_lists_stats;
449
450 /* insert new receiver (dev,canid,mask) -> (func,data) */
451
452 if (dev && (dev->type != ARPHRD_CAN || !can_get_ml_priv(dev)))
453 return -ENODEV;
454
455 if (dev && !net_eq(net, dev_net(dev)))
456 return -ENODEV;
457
458 rcv = kmem_cache_alloc(rcv_cache, GFP_KERNEL);
459 if (!rcv)
460 return -ENOMEM;
461
462 spin_lock_bh(&net->can.rcvlists_lock);
463
464 dev_rcv_lists = can_dev_rcv_lists_find(net, dev);
465 rcv_list = can_rcv_list_find(&can_id, &mask, dev_rcv_lists);
466
467 rcv->can_id = can_id;
468 rcv->mask = mask;
469 rcv->matches = 0;
470 rcv->func = func;
471 rcv->data = data;
472 rcv->ident = ident;
473 rcv->sk = sk;
474
475 hlist_add_head_rcu(&rcv->list, rcv_list);
476 dev_rcv_lists->entries++;
477
478 rcv_lists_stats->rcv_entries++;
479 rcv_lists_stats->rcv_entries_max = max(rcv_lists_stats->rcv_entries_max,
480 rcv_lists_stats->rcv_entries);
481 spin_unlock_bh(&net->can.rcvlists_lock);
482
483 return 0;
484 }
485 EXPORT_SYMBOL(can_rx_register);
486
487 /* can_rx_delete_receiver - rcu callback for single receiver entry removal */
488 static void can_rx_delete_receiver(struct rcu_head *rp)
489 {
490 struct receiver *rcv = container_of(rp, struct receiver, rcu);
491 struct sock *sk = rcv->sk;
492
493 kmem_cache_free(rcv_cache, rcv);
494 if (sk)
495 sock_put(sk);
496 }
497
498 /**
499 * can_rx_unregister - unsubscribe CAN frames from a specific interface
500 * @net: the applicable net namespace
501 * @dev: pointer to netdevice (NULL => unsubscribe from 'all' CAN devices list)
502 * @can_id: CAN identifier
503 * @mask: CAN mask
504 * @func: callback function on filter match
505 * @data: returned parameter for callback function
506 *
507 * Description:
508 * Removes subscription entry depending on given (subscription) values.
509 */
510 void can_rx_unregister(struct net *net, struct net_device *dev, canid_t can_id,
511 canid_t mask, void (*func)(struct sk_buff *, void *),
512 void *data)
513 {
514 struct receiver *rcv = NULL;
515 struct hlist_head *rcv_list;
516 struct can_rcv_lists_stats *rcv_lists_stats = net->can.rcv_lists_stats;
517 struct can_dev_rcv_lists *dev_rcv_lists;
518
519 if (dev && dev->type != ARPHRD_CAN)
520 return;
521
522 if (dev && !net_eq(net, dev_net(dev)))
523 return;
524
525 spin_lock_bh(&net->can.rcvlists_lock);
526
527 dev_rcv_lists = can_dev_rcv_lists_find(net, dev);
528 rcv_list = can_rcv_list_find(&can_id, &mask, dev_rcv_lists);
529
530 /* Search the receiver list for the item to delete. This should
531 * exist, since no receiver may be unregistered that hasn't
532 * been registered before.
533 */
534 hlist_for_each_entry_rcu(rcv, rcv_list, list) {
535 if (rcv->can_id == can_id && rcv->mask == mask &&
536 rcv->func == func && rcv->data == data)
537 break;
538 }
539
540 /* Check for bugs in CAN protocol implementations using af_can.c:
541 * 'rcv' will be NULL if no matching list item was found for removal.
542 * As this case may potentially happen when closing a socket while
543 * the notifier for removing the CAN netdev is running we just print
544 * a warning here.
545 */
546 if (!rcv) {
547 pr_warn("can: receive list entry not found for dev %s, id %03X, mask %03X\n",
548 DNAME(dev), can_id, mask);
549 goto out;
550 }
551
552 hlist_del_rcu(&rcv->list);
553 dev_rcv_lists->entries--;
554
555 if (rcv_lists_stats->rcv_entries > 0)
556 rcv_lists_stats->rcv_entries--;
557
558 out:
559 spin_unlock_bh(&net->can.rcvlists_lock);
560
561 /* schedule the receiver item for deletion */
562 if (rcv) {
563 if (rcv->sk)
564 sock_hold(rcv->sk);
565 call_rcu(&rcv->rcu, can_rx_delete_receiver);
566 }
567 }
568 EXPORT_SYMBOL(can_rx_unregister);
569
570 static inline void deliver(struct sk_buff *skb, struct receiver *rcv)
571 {
572 rcv->func(skb, rcv->data);
573 rcv->matches++;
574 }
575
576 static int can_rcv_filter(struct can_dev_rcv_lists *dev_rcv_lists, struct sk_buff *skb)
577 {
578 struct receiver *rcv;
579 int matches = 0;
580 struct can_frame *cf = (struct can_frame *)skb->data;
581 canid_t can_id = cf->can_id;
582
583 if (dev_rcv_lists->entries == 0)
584 return 0;
585
586 if (can_id & CAN_ERR_FLAG) {
587 /* check for error message frame entries only */
588 hlist_for_each_entry_rcu(rcv, &dev_rcv_lists->rx[RX_ERR], list) {
589 if (can_id & rcv->mask) {
590 deliver(skb, rcv);
591 matches++;
592 }
593 }
594 return matches;
595 }
596
597 /* check for unfiltered entries */
598 hlist_for_each_entry_rcu(rcv, &dev_rcv_lists->rx[RX_ALL], list) {
599 deliver(skb, rcv);
600 matches++;
601 }
602
603 /* check for can_id/mask entries */
604 hlist_for_each_entry_rcu(rcv, &dev_rcv_lists->rx[RX_FIL], list) {
605 if ((can_id & rcv->mask) == rcv->can_id) {
606 deliver(skb, rcv);
607 matches++;
608 }
609 }
610
611 /* check for inverted can_id/mask entries */
612 hlist_for_each_entry_rcu(rcv, &dev_rcv_lists->rx[RX_INV], list) {
613 if ((can_id & rcv->mask) != rcv->can_id) {
614 deliver(skb, rcv);
615 matches++;
616 }
617 }
618
619 /* check filterlists for single non-RTR can_ids */
620 if (can_id & CAN_RTR_FLAG)
621 return matches;
622
623 if (can_id & CAN_EFF_FLAG) {
624 hlist_for_each_entry_rcu(rcv, &dev_rcv_lists->rx_eff[effhash(can_id)], list) {
625 if (rcv->can_id == can_id) {
626 deliver(skb, rcv);
627 matches++;
628 }
629 }
630 } else {
631 can_id &= CAN_SFF_MASK;
632 hlist_for_each_entry_rcu(rcv, &dev_rcv_lists->rx_sff[can_id], list) {
633 deliver(skb, rcv);
634 matches++;
635 }
636 }
637
638 return matches;
639 }
640
641 static void can_receive(struct sk_buff *skb, struct net_device *dev)
642 {
643 struct can_dev_rcv_lists *dev_rcv_lists;
644 struct net *net = dev_net(dev);
645 struct can_pkg_stats *pkg_stats = net->can.pkg_stats;
646 int matches;
647
648 /* update statistics */
649 pkg_stats->rx_frames++;
650 pkg_stats->rx_frames_delta++;
651
652 /* create non-zero unique skb identifier together with *skb */
653 while (!(can_skb_prv(skb)->skbcnt))
654 can_skb_prv(skb)->skbcnt = atomic_inc_return(&skbcounter);
655
656 rcu_read_lock();
657
658 /* deliver the packet to sockets listening on all devices */
659 matches = can_rcv_filter(net->can.rx_alldev_list, skb);
660
661 /* find receive list for this device */
662 dev_rcv_lists = can_dev_rcv_lists_find(net, dev);
663 matches += can_rcv_filter(dev_rcv_lists, skb);
664
665 rcu_read_unlock();
666
667 /* consume the skbuff allocated by the netdevice driver */
668 consume_skb(skb);
669
670 if (matches > 0) {
671 pkg_stats->matches++;
672 pkg_stats->matches_delta++;
673 }
674 }
675
676 static int can_rcv(struct sk_buff *skb, struct net_device *dev,
677 struct packet_type *pt, struct net_device *orig_dev)
678 {
679 if (unlikely(dev->type != ARPHRD_CAN || !can_get_ml_priv(dev) || !can_is_can_skb(skb))) {
680 pr_warn_once("PF_CAN: dropped non conform CAN skbuff: dev type %d, len %d\n",
681 dev->type, skb->len);
682
683 kfree_skb(skb);
684 return NET_RX_DROP;
685 }
686
687 can_receive(skb, dev);
688 return NET_RX_SUCCESS;
689 }
690
691 static int canfd_rcv(struct sk_buff *skb, struct net_device *dev,
692 struct packet_type *pt, struct net_device *orig_dev)
693 {
694 if (unlikely(dev->type != ARPHRD_CAN || !can_get_ml_priv(dev) || !can_is_canfd_skb(skb))) {
695 pr_warn_once("PF_CAN: dropped non conform CAN FD skbuff: dev type %d, len %d\n",
696 dev->type, skb->len);
697
698 kfree_skb(skb);
699 return NET_RX_DROP;
700 }
701
702 can_receive(skb, dev);
703 return NET_RX_SUCCESS;
704 }
705
706 static int canxl_rcv(struct sk_buff *skb, struct net_device *dev,
707 struct packet_type *pt, struct net_device *orig_dev)
708 {
709 if (unlikely(dev->type != ARPHRD_CAN || !can_get_ml_priv(dev) || !can_is_canxl_skb(skb))) {
710 pr_warn_once("PF_CAN: dropped non conform CAN XL skbuff: dev type %d, len %d\n",
711 dev->type, skb->len);
712
713 kfree_skb(skb);
714 return NET_RX_DROP;
715 }
716
717 can_receive(skb, dev);
718 return NET_RX_SUCCESS;
719 }
720
721 /* af_can protocol functions */
722
723 /**
724 * can_proto_register - register CAN transport protocol
725 * @cp: pointer to CAN protocol structure
726 *
727 * Return:
728 * 0 on success
729 * -EINVAL invalid (out of range) protocol number
730 * -EBUSY protocol already in use
731 * -ENOBUF if proto_register() fails
732 */
733 int can_proto_register(const struct can_proto *cp)
734 {
735 int proto = cp->protocol;
736 int err = 0;
737
738 if (proto < 0 || proto >= CAN_NPROTO) {
739 pr_err("can: protocol number %d out of range\n", proto);
740 return -EINVAL;
741 }
742
743 err = proto_register(cp->prot, 0);
744 if (err < 0)
745 return err;
746
747 mutex_lock(&proto_tab_lock);
748
749 if (rcu_access_pointer(proto_tab[proto])) {
750 pr_err("can: protocol %d already registered\n", proto);
751 err = -EBUSY;
752 } else {
753 RCU_INIT_POINTER(proto_tab[proto], cp);
754 }
755
756 mutex_unlock(&proto_tab_lock);
757
758 if (err < 0)
759 proto_unregister(cp->prot);
760
761 return err;
762 }
763 EXPORT_SYMBOL(can_proto_register);
764
765 /**
766 * can_proto_unregister - unregister CAN transport protocol
767 * @cp: pointer to CAN protocol structure
768 */
769 void can_proto_unregister(const struct can_proto *cp)
770 {
771 int proto = cp->protocol;
772
773 mutex_lock(&proto_tab_lock);
774 BUG_ON(rcu_access_pointer(proto_tab[proto]) != cp);
775 RCU_INIT_POINTER(proto_tab[proto], NULL);
776 mutex_unlock(&proto_tab_lock);
777
778 synchronize_rcu();
779
780 proto_unregister(cp->prot);
781 }
782 EXPORT_SYMBOL(can_proto_unregister);
783
784 static int can_pernet_init(struct net *net)
785 {
786 spin_lock_init(&net->can.rcvlists_lock);
787 net->can.rx_alldev_list =
788 kzalloc(sizeof(*net->can.rx_alldev_list), GFP_KERNEL);
789 if (!net->can.rx_alldev_list)
790 goto out;
791 net->can.pkg_stats = kzalloc(sizeof(*net->can.pkg_stats), GFP_KERNEL);
792 if (!net->can.pkg_stats)
793 goto out_free_rx_alldev_list;
794 net->can.rcv_lists_stats = kzalloc(sizeof(*net->can.rcv_lists_stats), GFP_KERNEL);
795 if (!net->can.rcv_lists_stats)
796 goto out_free_pkg_stats;
797
798 if (IS_ENABLED(CONFIG_PROC_FS)) {
799 /* the statistics are updated every second (timer triggered) */
800 if (stats_timer) {
801 timer_setup(&net->can.stattimer, can_stat_update,
802 0);
803 mod_timer(&net->can.stattimer,
804 round_jiffies(jiffies + HZ));
805 }
806 net->can.pkg_stats->jiffies_init = jiffies;
807 can_init_proc(net);
808 }
809
810 return 0;
811
812 out_free_pkg_stats:
813 kfree(net->can.pkg_stats);
814 out_free_rx_alldev_list:
815 kfree(net->can.rx_alldev_list);
816 out:
817 return -ENOMEM;
818 }
819
820 static void can_pernet_exit(struct net *net)
821 {
822 if (IS_ENABLED(CONFIG_PROC_FS)) {
823 can_remove_proc(net);
824 if (stats_timer)
825 del_timer_sync(&net->can.stattimer);
826 }
827
828 kfree(net->can.rx_alldev_list);
829 kfree(net->can.pkg_stats);
830 kfree(net->can.rcv_lists_stats);
831 }
832
833 /* af_can module init/exit functions */
834
835 static struct packet_type can_packet __read_mostly = {
836 .type = cpu_to_be16(ETH_P_CAN),
837 .func = can_rcv,
838 };
839
840 static struct packet_type canfd_packet __read_mostly = {
841 .type = cpu_to_be16(ETH_P_CANFD),
842 .func = canfd_rcv,
843 };
844
845 static struct packet_type canxl_packet __read_mostly = {
846 .type = cpu_to_be16(ETH_P_CANXL),
847 .func = canxl_rcv,
848 };
849
850 static const struct net_proto_family can_family_ops = {
851 .family = PF_CAN,
852 .create = can_create,
853 .owner = THIS_MODULE,
854 };
855
856 static struct pernet_operations can_pernet_ops __read_mostly = {
857 .init = can_pernet_init,
858 .exit = can_pernet_exit,
859 };
860
861 static __init int can_init(void)
862 {
863 int err;
864
865 /* check for correct padding to be able to use the structs similarly */
866 BUILD_BUG_ON(offsetof(struct can_frame, len) !=
867 offsetof(struct canfd_frame, len) ||
868 offsetof(struct can_frame, len) !=
869 offsetof(struct canxl_frame, flags) ||
870 offsetof(struct can_frame, data) !=
871 offsetof(struct canfd_frame, data));
872
873 pr_info("can: controller area network core\n");
874
875 rcv_cache = kmem_cache_create("can_receiver", sizeof(struct receiver),
876 0, 0, NULL);
877 if (!rcv_cache)
878 return -ENOMEM;
879
880 err = register_pernet_subsys(&can_pernet_ops);
881 if (err)
882 goto out_pernet;
883
884 /* protocol register */
885 err = sock_register(&can_family_ops);
886 if (err)
887 goto out_sock;
888
889 dev_add_pack(&can_packet);
890 dev_add_pack(&canfd_packet);
891 dev_add_pack(&canxl_packet);
892
893 return 0;
894
895 out_sock:
896 unregister_pernet_subsys(&can_pernet_ops);
897 out_pernet:
898 kmem_cache_destroy(rcv_cache);
899
900 return err;
901 }
902
903 static __exit void can_exit(void)
904 {
905 /* protocol unregister */
906 dev_remove_pack(&canxl_packet);
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
918 module_init(can_init);
919 module_exit(can_exit);
920
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