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[linux/fpc-iii.git] / net / can / af_can.c
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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)
5 * Copyright (c) 2002-2017 Volkswagen Group Electronic Research
6 * All rights reserved.
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.
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.
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.
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.
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>
66 #include "af_can.h"
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>");
73 MODULE_ALIAS_NETPROTO(PF_CAN);
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)");
79 static struct kmem_cache *rcv_cache __read_mostly;
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);
85 static atomic_t skbcounter = ATOMIC_INIT(0);
87 /* af_can socket functions */
89 void can_sock_destruct(struct sock *sk)
91 skb_queue_purge(&sk->sk_receive_queue);
92 skb_queue_purge(&sk->sk_error_queue);
94 EXPORT_SYMBOL(can_sock_destruct);
96 static const struct can_proto *can_get_proto(int protocol)
98 const struct can_proto *cp;
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();
106 return cp;
109 static inline void can_put_proto(const struct can_proto *cp)
111 module_put(cp->prot->owner);
114 static int can_create(struct net *net, struct socket *sock, int protocol,
115 int kern)
117 struct sock *sk;
118 const struct can_proto *cp;
119 int err = 0;
121 sock->state = SS_UNCONNECTED;
123 if (protocol < 0 || protocol >= CAN_NPROTO)
124 return -EINVAL;
126 cp = can_get_proto(protocol);
128 #ifdef CONFIG_MODULES
129 if (!cp) {
130 /* try to load protocol module if kernel is modular */
132 err = request_module("can-proto-%d", protocol);
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
138 if (err)
139 pr_err_ratelimited("can: request_module (can-proto-%d) failed.\n",
140 protocol);
142 cp = can_get_proto(protocol);
144 #endif
146 /* check for available protocol and correct usage */
148 if (!cp)
149 return -EPROTONOSUPPORT;
151 if (cp->type != sock->type) {
152 err = -EPROTOTYPE;
153 goto errout;
156 sock->ops = cp->ops;
158 sk = sk_alloc(net, PF_CAN, GFP_KERNEL, cp->prot, kern);
159 if (!sk) {
160 err = -ENOMEM;
161 goto errout;
164 sock_init_data(sock, sk);
165 sk->sk_destruct = can_sock_destruct;
167 if (sk->sk_prot->init)
168 err = sk->sk_prot->init(sk);
170 if (err) {
171 /* release sk on errors */
172 sock_orphan(sk);
173 sock_put(sk);
176 errout:
177 can_put_proto(cp);
178 return err;
181 /* af_can tx path */
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!)
188 * Due to the loopback this routine must not be called from hardirq context.
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
199 int can_send(struct sk_buff *skb, int loop)
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;
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;
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
222 if (unlikely(skb->len > skb->dev->mtu && cfd->len > CAN_MAX_DLEN)) {
223 err = -EMSGSIZE;
224 goto inval_skb;
227 if (unlikely(skb->dev->type != ARPHRD_CAN)) {
228 err = -EPERM;
229 goto inval_skb;
232 if (unlikely(!(skb->dev->flags & IFF_UP))) {
233 err = -ENETDOWN;
234 goto inval_skb;
237 skb->ip_summed = CHECKSUM_UNNECESSARY;
239 skb_reset_mac_header(skb);
240 skb_reset_network_header(skb);
241 skb_reset_transport_header(skb);
243 if (loop) {
244 /* local loopback of sent CAN frames */
246 /* indication for the CAN driver: do loopback */
247 skb->pkt_type = PACKET_LOOPBACK;
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.
257 if (!(skb->dev->flags & IFF_ECHO)) {
258 /* If the interface is not capable to do loopback
259 * itself, we do it here.
261 newskb = skb_clone(skb, GFP_ATOMIC);
262 if (!newskb) {
263 kfree_skb(skb);
264 return -ENOMEM;
267 can_skb_set_owner(newskb, skb->sk);
268 newskb->ip_summed = CHECKSUM_UNNECESSARY;
269 newskb->pkt_type = PACKET_BROADCAST;
271 } else {
272 /* indication for the CAN driver: no loopback required */
273 skb->pkt_type = PACKET_HOST;
276 /* send to netdevice */
277 err = dev_queue_xmit(skb);
278 if (err > 0)
279 err = net_xmit_errno(err);
281 if (err) {
282 kfree_skb(newskb);
283 return err;
286 if (newskb)
287 netif_rx_ni(newskb);
289 /* update statistics */
290 pkg_stats->tx_frames++;
291 pkg_stats->tx_frames_delta++;
293 return 0;
295 inval_skb:
296 kfree_skb(skb);
297 return err;
299 EXPORT_SYMBOL(can_send);
301 /* af_can rx path */
303 static struct can_dev_rcv_lists *can_dev_rcv_lists_find(struct net *net,
304 struct net_device *dev)
306 if (dev) {
307 struct can_ml_priv *ml_priv = dev->ml_priv;
308 return &ml_priv->dev_rcv_lists;
309 } else {
310 return net->can.rx_alldev_list;
315 * effhash - hash function for 29 bit CAN identifier reduction
316 * @can_id: 29 bit CAN identifier
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)
323 * Return:
324 * Hash value from 0x000 - 0x3FF ( enforced by CAN_EFF_RCV_HASH_BITS mask )
326 static unsigned int effhash(canid_t can_id)
328 unsigned int hash;
330 hash = can_id;
331 hash ^= can_id >> CAN_EFF_RCV_HASH_BITS;
332 hash ^= can_id >> (2 * CAN_EFF_RCV_HASH_BITS);
334 return hash & ((1 << CAN_EFF_RCV_HASH_BITS) - 1);
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 * @d: pointer to the device filter struct
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.
348 * A filter matches in general, when
350 * <received_can_id> & mask == can_id & mask
352 * so every bit set in the mask (even CAN_EFF_FLAG, CAN_RTR_FLAG) describe
353 * relevant bits for the filter.
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.
359 * Return:
360 * Pointer to optimal filterlist for the given can_id/mask pair.
361 * Constistency checked mask.
362 * Reduced can_id to have a preprocessed filter compare value.
364 static struct hlist_head *can_rcv_list_find(canid_t *can_id, canid_t *mask,
365 struct can_dev_rcv_lists *dev_rcv_lists)
367 canid_t inv = *can_id & CAN_INV_FILTER; /* save flag before masking */
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];
376 /* with cleared CAN_ERR_FLAG we have a simple mask/value filterpair */
378 #define CAN_EFF_RTR_FLAGS (CAN_EFF_FLAG | CAN_RTR_FLAG)
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);
384 /* reduce condition testing at receive time */
385 *can_id &= *mask;
387 /* inverse can_id/can_mask filter */
388 if (inv)
389 return &dev_rcv_lists->rx[RX_INV];
391 /* mask == 0 => no condition testing at receive time */
392 if (!(*mask))
393 return &dev_rcv_lists->rx[RX_ALL];
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];
407 /* default: filter via can_id/can_mask */
408 return &dev_rcv_lists->rx[RX_FIL];
412 * can_rx_register - subscribe CAN frames from a specific interface
413 * @dev: pointer to netdevice (NULL => subcribe 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)
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
425 * <received_can_id> & mask == can_id & mask
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).
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().
436 * Return:
437 * 0 on success
438 * -ENOMEM on missing cache mem to create subscription entry
439 * -ENODEV unknown device
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)
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 int err = 0;
451 /* insert new receiver (dev,canid,mask) -> (func,data) */
453 if (dev && dev->type != ARPHRD_CAN)
454 return -ENODEV;
456 if (dev && !net_eq(net, dev_net(dev)))
457 return -ENODEV;
459 rcv = kmem_cache_alloc(rcv_cache, GFP_KERNEL);
460 if (!rcv)
461 return -ENOMEM;
463 spin_lock_bh(&net->can.rcvlists_lock);
465 dev_rcv_lists = can_dev_rcv_lists_find(net, dev);
466 rcv_list = can_rcv_list_find(&can_id, &mask, dev_rcv_lists);
468 rcv->can_id = can_id;
469 rcv->mask = mask;
470 rcv->matches = 0;
471 rcv->func = func;
472 rcv->data = data;
473 rcv->ident = ident;
474 rcv->sk = sk;
476 hlist_add_head_rcu(&rcv->list, rcv_list);
477 dev_rcv_lists->entries++;
479 rcv_lists_stats->rcv_entries++;
480 rcv_lists_stats->rcv_entries_max = max(rcv_lists_stats->rcv_entries_max,
481 rcv_lists_stats->rcv_entries);
482 spin_unlock_bh(&net->can.rcvlists_lock);
484 return err;
486 EXPORT_SYMBOL(can_rx_register);
488 /* can_rx_delete_receiver - rcu callback for single receiver entry removal */
489 static void can_rx_delete_receiver(struct rcu_head *rp)
491 struct receiver *rcv = container_of(rp, struct receiver, rcu);
492 struct sock *sk = rcv->sk;
494 kmem_cache_free(rcv_cache, rcv);
495 if (sk)
496 sock_put(sk);
500 * can_rx_unregister - unsubscribe CAN frames from a specific interface
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
507 * Description:
508 * Removes subscription entry depending on given (subscription) values.
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)
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;
519 if (dev && dev->type != ARPHRD_CAN)
520 return;
522 if (dev && !net_eq(net, dev_net(dev)))
523 return;
525 spin_lock_bh(&net->can.rcvlists_lock);
527 dev_rcv_lists = can_dev_rcv_lists_find(net, dev);
528 rcv_list = can_rcv_list_find(&can_id, &mask, dev_rcv_lists);
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.
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;
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.
543 if (!rcv) {
544 WARN(1, "BUG: receive list entry not found for dev %s, id %03X, mask %03X\n",
545 DNAME(dev), can_id, mask);
546 goto out;
549 hlist_del_rcu(&rcv->list);
550 dev_rcv_lists->entries--;
552 if (rcv_lists_stats->rcv_entries > 0)
553 rcv_lists_stats->rcv_entries--;
555 out:
556 spin_unlock_bh(&net->can.rcvlists_lock);
558 /* schedule the receiver item for deletion */
559 if (rcv) {
560 if (rcv->sk)
561 sock_hold(rcv->sk);
562 call_rcu(&rcv->rcu, can_rx_delete_receiver);
565 EXPORT_SYMBOL(can_rx_unregister);
567 static inline void deliver(struct sk_buff *skb, struct receiver *rcv)
569 rcv->func(skb, rcv->data);
570 rcv->matches++;
573 static int can_rcv_filter(struct can_dev_rcv_lists *dev_rcv_lists, struct sk_buff *skb)
575 struct receiver *rcv;
576 int matches = 0;
577 struct can_frame *cf = (struct can_frame *)skb->data;
578 canid_t can_id = cf->can_id;
580 if (dev_rcv_lists->entries == 0)
581 return 0;
583 if (can_id & CAN_ERR_FLAG) {
584 /* check for error message frame entries only */
585 hlist_for_each_entry_rcu(rcv, &dev_rcv_lists->rx[RX_ERR], list) {
586 if (can_id & rcv->mask) {
587 deliver(skb, rcv);
588 matches++;
591 return matches;
594 /* check for unfiltered entries */
595 hlist_for_each_entry_rcu(rcv, &dev_rcv_lists->rx[RX_ALL], list) {
596 deliver(skb, rcv);
597 matches++;
600 /* check for can_id/mask entries */
601 hlist_for_each_entry_rcu(rcv, &dev_rcv_lists->rx[RX_FIL], list) {
602 if ((can_id & rcv->mask) == rcv->can_id) {
603 deliver(skb, rcv);
604 matches++;
608 /* check for inverted can_id/mask entries */
609 hlist_for_each_entry_rcu(rcv, &dev_rcv_lists->rx[RX_INV], list) {
610 if ((can_id & rcv->mask) != rcv->can_id) {
611 deliver(skb, rcv);
612 matches++;
616 /* check filterlists for single non-RTR can_ids */
617 if (can_id & CAN_RTR_FLAG)
618 return matches;
620 if (can_id & CAN_EFF_FLAG) {
621 hlist_for_each_entry_rcu(rcv, &dev_rcv_lists->rx_eff[effhash(can_id)], list) {
622 if (rcv->can_id == can_id) {
623 deliver(skb, rcv);
624 matches++;
627 } else {
628 can_id &= CAN_SFF_MASK;
629 hlist_for_each_entry_rcu(rcv, &dev_rcv_lists->rx_sff[can_id], list) {
630 deliver(skb, rcv);
631 matches++;
635 return matches;
638 static void can_receive(struct sk_buff *skb, struct net_device *dev)
640 struct can_dev_rcv_lists *dev_rcv_lists;
641 struct net *net = dev_net(dev);
642 struct can_pkg_stats *pkg_stats = net->can.pkg_stats;
643 int matches;
645 /* update statistics */
646 pkg_stats->rx_frames++;
647 pkg_stats->rx_frames_delta++;
649 /* create non-zero unique skb identifier together with *skb */
650 while (!(can_skb_prv(skb)->skbcnt))
651 can_skb_prv(skb)->skbcnt = atomic_inc_return(&skbcounter);
653 rcu_read_lock();
655 /* deliver the packet to sockets listening on all devices */
656 matches = can_rcv_filter(net->can.rx_alldev_list, skb);
658 /* find receive list for this device */
659 dev_rcv_lists = can_dev_rcv_lists_find(net, dev);
660 matches += can_rcv_filter(dev_rcv_lists, skb);
662 rcu_read_unlock();
664 /* consume the skbuff allocated by the netdevice driver */
665 consume_skb(skb);
667 if (matches > 0) {
668 pkg_stats->matches++;
669 pkg_stats->matches_delta++;
673 static int can_rcv(struct sk_buff *skb, struct net_device *dev,
674 struct packet_type *pt, struct net_device *orig_dev)
676 struct canfd_frame *cfd = (struct canfd_frame *)skb->data;
678 if (unlikely(dev->type != ARPHRD_CAN || skb->len != CAN_MTU ||
679 cfd->len > CAN_MAX_DLEN)) {
680 pr_warn_once("PF_CAN: dropped non conform CAN skbuf: dev type %d, len %d, datalen %d\n",
681 dev->type, skb->len, cfd->len);
682 kfree_skb(skb);
683 return NET_RX_DROP;
686 can_receive(skb, dev);
687 return NET_RX_SUCCESS;
690 static int canfd_rcv(struct sk_buff *skb, struct net_device *dev,
691 struct packet_type *pt, struct net_device *orig_dev)
693 struct canfd_frame *cfd = (struct canfd_frame *)skb->data;
695 if (unlikely(dev->type != ARPHRD_CAN || skb->len != CANFD_MTU ||
696 cfd->len > CANFD_MAX_DLEN)) {
697 pr_warn_once("PF_CAN: dropped non conform CAN FD skbuf: dev type %d, len %d, datalen %d\n",
698 dev->type, skb->len, cfd->len);
699 kfree_skb(skb);
700 return NET_RX_DROP;
703 can_receive(skb, dev);
704 return NET_RX_SUCCESS;
707 /* af_can protocol functions */
710 * can_proto_register - register CAN transport protocol
711 * @cp: pointer to CAN protocol structure
713 * Return:
714 * 0 on success
715 * -EINVAL invalid (out of range) protocol number
716 * -EBUSY protocol already in use
717 * -ENOBUF if proto_register() fails
719 int can_proto_register(const struct can_proto *cp)
721 int proto = cp->protocol;
722 int err = 0;
724 if (proto < 0 || proto >= CAN_NPROTO) {
725 pr_err("can: protocol number %d out of range\n", proto);
726 return -EINVAL;
729 err = proto_register(cp->prot, 0);
730 if (err < 0)
731 return err;
733 mutex_lock(&proto_tab_lock);
735 if (rcu_access_pointer(proto_tab[proto])) {
736 pr_err("can: protocol %d already registered\n", proto);
737 err = -EBUSY;
738 } else {
739 RCU_INIT_POINTER(proto_tab[proto], cp);
742 mutex_unlock(&proto_tab_lock);
744 if (err < 0)
745 proto_unregister(cp->prot);
747 return err;
749 EXPORT_SYMBOL(can_proto_register);
752 * can_proto_unregister - unregister CAN transport protocol
753 * @cp: pointer to CAN protocol structure
755 void can_proto_unregister(const struct can_proto *cp)
757 int proto = cp->protocol;
759 mutex_lock(&proto_tab_lock);
760 BUG_ON(rcu_access_pointer(proto_tab[proto]) != cp);
761 RCU_INIT_POINTER(proto_tab[proto], NULL);
762 mutex_unlock(&proto_tab_lock);
764 synchronize_rcu();
766 proto_unregister(cp->prot);
768 EXPORT_SYMBOL(can_proto_unregister);
770 /* af_can notifier to create/remove CAN netdevice specific structs */
771 static int can_notifier(struct notifier_block *nb, unsigned long msg,
772 void *ptr)
774 struct net_device *dev = netdev_notifier_info_to_dev(ptr);
776 if (dev->type != ARPHRD_CAN)
777 return NOTIFY_DONE;
779 switch (msg) {
780 case NETDEV_REGISTER:
781 WARN(!dev->ml_priv,
782 "No CAN mid layer private allocated, please fix your driver and use alloc_candev()!\n");
783 break;
786 return NOTIFY_DONE;
789 static int can_pernet_init(struct net *net)
791 spin_lock_init(&net->can.rcvlists_lock);
792 net->can.rx_alldev_list =
793 kzalloc(sizeof(*net->can.rx_alldev_list), GFP_KERNEL);
794 if (!net->can.rx_alldev_list)
795 goto out;
796 net->can.pkg_stats = kzalloc(sizeof(*net->can.pkg_stats), GFP_KERNEL);
797 if (!net->can.pkg_stats)
798 goto out_free_rx_alldev_list;
799 net->can.rcv_lists_stats = kzalloc(sizeof(*net->can.rcv_lists_stats), GFP_KERNEL);
800 if (!net->can.rcv_lists_stats)
801 goto out_free_pkg_stats;
803 if (IS_ENABLED(CONFIG_PROC_FS)) {
804 /* the statistics are updated every second (timer triggered) */
805 if (stats_timer) {
806 timer_setup(&net->can.stattimer, can_stat_update,
808 mod_timer(&net->can.stattimer,
809 round_jiffies(jiffies + HZ));
811 net->can.pkg_stats->jiffies_init = jiffies;
812 can_init_proc(net);
815 return 0;
817 out_free_pkg_stats:
818 kfree(net->can.pkg_stats);
819 out_free_rx_alldev_list:
820 kfree(net->can.rx_alldev_list);
821 out:
822 return -ENOMEM;
825 static void can_pernet_exit(struct net *net)
827 if (IS_ENABLED(CONFIG_PROC_FS)) {
828 can_remove_proc(net);
829 if (stats_timer)
830 del_timer_sync(&net->can.stattimer);
833 kfree(net->can.rx_alldev_list);
834 kfree(net->can.pkg_stats);
835 kfree(net->can.rcv_lists_stats);
838 /* af_can module init/exit functions */
840 static struct packet_type can_packet __read_mostly = {
841 .type = cpu_to_be16(ETH_P_CAN),
842 .func = can_rcv,
845 static struct packet_type canfd_packet __read_mostly = {
846 .type = cpu_to_be16(ETH_P_CANFD),
847 .func = canfd_rcv,
850 static const struct net_proto_family can_family_ops = {
851 .family = PF_CAN,
852 .create = can_create,
853 .owner = THIS_MODULE,
856 /* notifier block for netdevice event */
857 static struct notifier_block can_netdev_notifier __read_mostly = {
858 .notifier_call = can_notifier,
861 static struct pernet_operations can_pernet_ops __read_mostly = {
862 .init = can_pernet_init,
863 .exit = can_pernet_exit,
866 static __init int can_init(void)
868 int err;
870 /* check for correct padding to be able to use the structs similarly */
871 BUILD_BUG_ON(offsetof(struct can_frame, can_dlc) !=
872 offsetof(struct canfd_frame, len) ||
873 offsetof(struct can_frame, data) !=
874 offsetof(struct canfd_frame, data));
876 pr_info("can: controller area network core (" CAN_VERSION_STRING ")\n");
878 rcv_cache = kmem_cache_create("can_receiver", sizeof(struct receiver),
879 0, 0, NULL);
880 if (!rcv_cache)
881 return -ENOMEM;
883 err = register_pernet_subsys(&can_pernet_ops);
884 if (err)
885 goto out_pernet;
887 /* protocol register */
888 err = sock_register(&can_family_ops);
889 if (err)
890 goto out_sock;
891 err = register_netdevice_notifier(&can_netdev_notifier);
892 if (err)
893 goto out_notifier;
895 dev_add_pack(&can_packet);
896 dev_add_pack(&canfd_packet);
898 return 0;
900 out_notifier:
901 sock_unregister(PF_CAN);
902 out_sock:
903 unregister_pernet_subsys(&can_pernet_ops);
904 out_pernet:
905 kmem_cache_destroy(rcv_cache);
907 return err;
910 static __exit void can_exit(void)
912 /* protocol unregister */
913 dev_remove_pack(&canfd_packet);
914 dev_remove_pack(&can_packet);
915 unregister_netdevice_notifier(&can_netdev_notifier);
916 sock_unregister(PF_CAN);
918 unregister_pernet_subsys(&can_pernet_ops);
920 rcu_barrier(); /* Wait for completion of call_rcu()'s */
922 kmem_cache_destroy(rcv_cache);
925 module_init(can_init);
926 module_exit(can_exit);