2 * af_can.c - Protocol family CAN core module
3 * (used by different CAN protocol modules)
5 * Copyright (c) 2002-2007 Volkswagen Group Electronic Research
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
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
43 #include <linux/module.h>
44 #include <linux/init.h>
45 #include <linux/kmod.h>
46 #include <linux/slab.h>
47 #include <linux/list.h>
48 #include <linux/spinlock.h>
49 #include <linux/rcupdate.h>
50 #include <linux/uaccess.h>
51 #include <linux/net.h>
52 #include <linux/netdevice.h>
53 #include <linux/socket.h>
54 #include <linux/if_ether.h>
55 #include <linux/if_arp.h>
56 #include <linux/skbuff.h>
57 #include <linux/can.h>
58 #include <linux/can/core.h>
59 #include <linux/ratelimit.h>
60 #include <net/net_namespace.h>
65 static __initdata const char banner[] = KERN_INFO
66 "can: controller area network core (" CAN_VERSION_STRING ")\n";
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, S_IRUGO);
77 MODULE_PARM_DESC(stats_timer, "enable timer for statistics (default:on)");
79 /* receive filters subscribed for 'all' CAN devices */
80 struct dev_rcv_lists can_rx_alldev_list;
81 static DEFINE_SPINLOCK(can_rcvlists_lock);
83 static struct kmem_cache *rcv_cache __read_mostly;
85 /* table of registered CAN protocols */
86 static const struct can_proto *proto_tab[CAN_NPROTO] __read_mostly;
87 static DEFINE_MUTEX(proto_tab_lock);
89 struct timer_list can_stattimer; /* timer for statistics update */
90 struct s_stats can_stats; /* packet statistics */
91 struct s_pstats can_pstats; /* receive list statistics */
94 * af_can socket functions
97 int can_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
99 struct sock *sk = sock->sk;
104 return sock_get_timestamp(sk, (struct timeval __user *)arg);
110 EXPORT_SYMBOL(can_ioctl);
112 static void can_sock_destruct(struct sock *sk)
114 skb_queue_purge(&sk->sk_receive_queue);
117 static const struct can_proto *can_get_proto(int protocol)
119 const struct can_proto *cp;
122 cp = rcu_dereference(proto_tab[protocol]);
123 if (cp && !try_module_get(cp->prot->owner))
130 static inline void can_put_proto(const struct can_proto *cp)
132 module_put(cp->prot->owner);
135 static int can_create(struct net *net, struct socket *sock, int protocol,
139 const struct can_proto *cp;
142 sock->state = SS_UNCONNECTED;
144 if (protocol < 0 || protocol >= CAN_NPROTO)
147 if (!net_eq(net, &init_net))
148 return -EAFNOSUPPORT;
150 cp = can_get_proto(protocol);
152 #ifdef CONFIG_MODULES
154 /* try to load protocol module if kernel is modular */
156 err = request_module("can-proto-%d", protocol);
159 * In case of error we only print a message but don't
160 * return the error code immediately. Below we will
161 * return -EPROTONOSUPPORT
164 printk_ratelimited(KERN_ERR "can: request_module "
165 "(can-proto-%d) failed.\n", protocol);
167 cp = can_get_proto(protocol);
171 /* check for available protocol and correct usage */
174 return -EPROTONOSUPPORT;
176 if (cp->type != sock->type) {
183 sk = sk_alloc(net, PF_CAN, GFP_KERNEL, cp->prot);
189 sock_init_data(sock, sk);
190 sk->sk_destruct = can_sock_destruct;
192 if (sk->sk_prot->init)
193 err = sk->sk_prot->init(sk);
196 /* release sk on errors */
211 * can_send - transmit a CAN frame (optional with local loopback)
212 * @skb: pointer to socket buffer with CAN frame in data section
213 * @loop: loopback for listeners on local CAN sockets (recommended default!)
215 * Due to the loopback this routine must not be called from hardirq context.
219 * -ENETDOWN when the selected interface is down
220 * -ENOBUFS on full driver queue (see net_xmit_errno())
221 * -ENOMEM when local loopback failed at calling skb_clone()
222 * -EPERM when trying to send on a non-CAN interface
223 * -EINVAL when the skb->data does not contain a valid CAN frame
225 int can_send(struct sk_buff *skb, int loop)
227 struct sk_buff *newskb = NULL;
228 struct can_frame *cf = (struct can_frame *)skb->data;
231 if (skb->len != sizeof(struct can_frame) || cf->can_dlc > 8) {
236 if (skb->dev->type != ARPHRD_CAN) {
241 if (!(skb->dev->flags & IFF_UP)) {
246 skb->protocol = htons(ETH_P_CAN);
247 skb->ip_summed = CHECKSUM_UNNECESSARY;
249 skb_reset_mac_header(skb);
250 skb_reset_network_header(skb);
251 skb_reset_transport_header(skb);
254 /* local loopback of sent CAN frames */
256 /* indication for the CAN driver: do loopback */
257 skb->pkt_type = PACKET_LOOPBACK;
260 * The reference to the originating sock may be required
261 * by the receiving socket to check whether the frame is
262 * its own. Example: can_raw sockopt CAN_RAW_RECV_OWN_MSGS
263 * Therefore we have to ensure that skb->sk remains the
264 * reference to the originating sock by restoring skb->sk
265 * after each skb_clone() or skb_orphan() usage.
268 if (!(skb->dev->flags & IFF_ECHO)) {
270 * If the interface is not capable to do loopback
271 * itself, we do it here.
273 newskb = skb_clone(skb, GFP_ATOMIC);
279 newskb->sk = skb->sk;
280 newskb->ip_summed = CHECKSUM_UNNECESSARY;
281 newskb->pkt_type = PACKET_BROADCAST;
284 /* indication for the CAN driver: no loopback required */
285 skb->pkt_type = PACKET_HOST;
288 /* send to netdevice */
289 err = dev_queue_xmit(skb);
291 err = net_xmit_errno(err);
301 /* update statistics */
302 can_stats.tx_frames++;
303 can_stats.tx_frames_delta++;
307 EXPORT_SYMBOL(can_send);
313 static struct dev_rcv_lists *find_dev_rcv_lists(struct net_device *dev)
316 return &can_rx_alldev_list;
318 return (struct dev_rcv_lists *)dev->ml_priv;
322 * find_rcv_list - determine optimal filterlist inside device filter struct
323 * @can_id: pointer to CAN identifier of a given can_filter
324 * @mask: pointer to CAN mask of a given can_filter
325 * @d: pointer to the device filter struct
328 * Returns the optimal filterlist to reduce the filter handling in the
329 * receive path. This function is called by service functions that need
330 * to register or unregister a can_filter in the filter lists.
332 * A filter matches in general, when
334 * <received_can_id> & mask == can_id & mask
336 * so every bit set in the mask (even CAN_EFF_FLAG, CAN_RTR_FLAG) describe
337 * relevant bits for the filter.
339 * The filter can be inverted (CAN_INV_FILTER bit set in can_id) or it can
340 * filter for error frames (CAN_ERR_FLAG bit set in mask). For error frames
341 * there is a special filterlist and a special rx path filter handling.
344 * Pointer to optimal filterlist for the given can_id/mask pair.
345 * Constistency checked mask.
346 * Reduced can_id to have a preprocessed filter compare value.
348 static struct hlist_head *find_rcv_list(canid_t *can_id, canid_t *mask,
349 struct dev_rcv_lists *d)
351 canid_t inv = *can_id & CAN_INV_FILTER; /* save flag before masking */
353 /* filter for error frames in extra filterlist */
354 if (*mask & CAN_ERR_FLAG) {
355 /* clear CAN_ERR_FLAG in filter entry */
356 *mask &= CAN_ERR_MASK;
357 return &d->rx[RX_ERR];
360 /* with cleared CAN_ERR_FLAG we have a simple mask/value filterpair */
362 #define CAN_EFF_RTR_FLAGS (CAN_EFF_FLAG | CAN_RTR_FLAG)
364 /* ensure valid values in can_mask for 'SFF only' frame filtering */
365 if ((*mask & CAN_EFF_FLAG) && !(*can_id & CAN_EFF_FLAG))
366 *mask &= (CAN_SFF_MASK | CAN_EFF_RTR_FLAGS);
368 /* reduce condition testing at receive time */
371 /* inverse can_id/can_mask filter */
373 return &d->rx[RX_INV];
375 /* mask == 0 => no condition testing at receive time */
377 return &d->rx[RX_ALL];
379 /* extra filterlists for the subscription of a single non-RTR can_id */
380 if (((*mask & CAN_EFF_RTR_FLAGS) == CAN_EFF_RTR_FLAGS) &&
381 !(*can_id & CAN_RTR_FLAG)) {
383 if (*can_id & CAN_EFF_FLAG) {
384 if (*mask == (CAN_EFF_MASK | CAN_EFF_RTR_FLAGS)) {
385 /* RFC: a future use-case for hash-tables? */
386 return &d->rx[RX_EFF];
389 if (*mask == (CAN_SFF_MASK | CAN_EFF_RTR_FLAGS))
390 return &d->rx_sff[*can_id];
394 /* default: filter via can_id/can_mask */
395 return &d->rx[RX_FIL];
399 * can_rx_register - subscribe CAN frames from a specific interface
400 * @dev: pointer to netdevice (NULL => subcribe from 'all' CAN devices list)
401 * @can_id: CAN identifier (see description)
402 * @mask: CAN mask (see description)
403 * @func: callback function on filter match
404 * @data: returned parameter for callback function
405 * @ident: string for calling module indentification
406 * @sk: socket pointer (might be NULL)
409 * Invokes the callback function with the received sk_buff and the given
410 * parameter 'data' on a matching receive filter. A filter matches, when
412 * <received_can_id> & mask == can_id & mask
414 * The filter can be inverted (CAN_INV_FILTER bit set in can_id) or it can
415 * filter for error frames (CAN_ERR_FLAG bit set in mask).
417 * The provided pointer to the sk_buff is guaranteed to be valid as long as
418 * the callback function is running. The callback function must *not* free
419 * the given sk_buff while processing it's task. When the given sk_buff is
420 * needed after the end of the callback function it must be cloned inside
421 * the callback function with skb_clone().
425 * -ENOMEM on missing cache mem to create subscription entry
426 * -ENODEV unknown device
428 int can_rx_register(struct net_device *dev, canid_t can_id, canid_t mask,
429 void (*func)(struct sk_buff *, void *), void *data,
430 char *ident, struct sock *sk)
433 struct hlist_head *rl;
434 struct dev_rcv_lists *d;
437 /* insert new receiver (dev,canid,mask) -> (func,data) */
439 if (dev && dev->type != ARPHRD_CAN)
442 r = kmem_cache_alloc(rcv_cache, GFP_KERNEL);
446 spin_lock(&can_rcvlists_lock);
448 d = find_dev_rcv_lists(dev);
450 rl = find_rcv_list(&can_id, &mask, d);
460 hlist_add_head_rcu(&r->list, rl);
463 can_pstats.rcv_entries++;
464 if (can_pstats.rcv_entries_max < can_pstats.rcv_entries)
465 can_pstats.rcv_entries_max = can_pstats.rcv_entries;
467 kmem_cache_free(rcv_cache, r);
471 spin_unlock(&can_rcvlists_lock);
475 EXPORT_SYMBOL(can_rx_register);
478 * can_rx_delete_receiver - rcu callback for single receiver entry removal
480 static void can_rx_delete_receiver(struct rcu_head *rp)
482 struct receiver *r = container_of(rp, struct receiver, rcu);
483 struct sock *sk = r->sk;
485 kmem_cache_free(rcv_cache, r);
491 * can_rx_unregister - unsubscribe CAN frames from a specific interface
492 * @dev: pointer to netdevice (NULL => unsubcribe from 'all' CAN devices list)
493 * @can_id: CAN identifier
495 * @func: callback function on filter match
496 * @data: returned parameter for callback function
499 * Removes subscription entry depending on given (subscription) values.
501 void can_rx_unregister(struct net_device *dev, canid_t can_id, canid_t mask,
502 void (*func)(struct sk_buff *, void *), void *data)
504 struct receiver *r = NULL;
505 struct hlist_head *rl;
506 struct hlist_node *next;
507 struct dev_rcv_lists *d;
509 if (dev && dev->type != ARPHRD_CAN)
512 spin_lock(&can_rcvlists_lock);
514 d = find_dev_rcv_lists(dev);
516 printk(KERN_ERR "BUG: receive list not found for "
517 "dev %s, id %03X, mask %03X\n",
518 DNAME(dev), can_id, mask);
522 rl = find_rcv_list(&can_id, &mask, d);
525 * Search the receiver list for the item to delete. This should
526 * exist, since no receiver may be unregistered that hasn't
527 * been registered before.
530 hlist_for_each_entry_rcu(r, next, rl, list) {
531 if (r->can_id == can_id && r->mask == mask &&
532 r->func == func && r->data == data)
537 * Check for bugs in CAN protocol implementations:
538 * If no matching list item was found, the list cursor variable next
539 * will be NULL, while r will point to the last item of the list.
543 printk(KERN_ERR "BUG: receive list entry not found for "
544 "dev %s, id %03X, mask %03X\n",
545 DNAME(dev), can_id, mask);
550 hlist_del_rcu(&r->list);
553 if (can_pstats.rcv_entries > 0)
554 can_pstats.rcv_entries--;
556 /* remove device structure requested by NETDEV_UNREGISTER */
557 if (d->remove_on_zero_entries && !d->entries) {
563 spin_unlock(&can_rcvlists_lock);
565 /* schedule the receiver item for deletion */
569 call_rcu(&r->rcu, can_rx_delete_receiver);
572 EXPORT_SYMBOL(can_rx_unregister);
574 static inline void deliver(struct sk_buff *skb, struct receiver *r)
576 r->func(skb, r->data);
580 static int can_rcv_filter(struct dev_rcv_lists *d, struct sk_buff *skb)
583 struct hlist_node *n;
585 struct can_frame *cf = (struct can_frame *)skb->data;
586 canid_t can_id = cf->can_id;
591 if (can_id & CAN_ERR_FLAG) {
592 /* check for error frame entries only */
593 hlist_for_each_entry_rcu(r, n, &d->rx[RX_ERR], list) {
594 if (can_id & r->mask) {
602 /* check for unfiltered entries */
603 hlist_for_each_entry_rcu(r, n, &d->rx[RX_ALL], list) {
608 /* check for can_id/mask entries */
609 hlist_for_each_entry_rcu(r, n, &d->rx[RX_FIL], list) {
610 if ((can_id & r->mask) == r->can_id) {
616 /* check for inverted can_id/mask entries */
617 hlist_for_each_entry_rcu(r, n, &d->rx[RX_INV], list) {
618 if ((can_id & r->mask) != r->can_id) {
624 /* check filterlists for single non-RTR can_ids */
625 if (can_id & CAN_RTR_FLAG)
628 if (can_id & CAN_EFF_FLAG) {
629 hlist_for_each_entry_rcu(r, n, &d->rx[RX_EFF], list) {
630 if (r->can_id == can_id) {
636 can_id &= CAN_SFF_MASK;
637 hlist_for_each_entry_rcu(r, n, &d->rx_sff[can_id], list) {
646 static int can_rcv(struct sk_buff *skb, struct net_device *dev,
647 struct packet_type *pt, struct net_device *orig_dev)
649 struct dev_rcv_lists *d;
650 struct can_frame *cf = (struct can_frame *)skb->data;
653 if (!net_eq(dev_net(dev), &init_net))
656 if (unlikely(dev->type != ARPHRD_CAN ||
657 skb->len != sizeof(struct can_frame) ||
659 pr_warn_once("PF_CAN: dropped non conform CAN skbuf: dev type %d, len %d, can_dlc %d\n",
660 dev->type, skb->len, cf->can_dlc);
664 /* update statistics */
665 can_stats.rx_frames++;
666 can_stats.rx_frames_delta++;
670 /* deliver the packet to sockets listening on all devices */
671 matches = can_rcv_filter(&can_rx_alldev_list, skb);
673 /* find receive list for this device */
674 d = find_dev_rcv_lists(dev);
676 matches += can_rcv_filter(d, skb);
680 /* consume the skbuff allocated by the netdevice driver */
685 can_stats.matches_delta++;
688 return NET_RX_SUCCESS;
696 * af_can protocol functions
700 * can_proto_register - register CAN transport protocol
701 * @cp: pointer to CAN protocol structure
705 * -EINVAL invalid (out of range) protocol number
706 * -EBUSY protocol already in use
707 * -ENOBUF if proto_register() fails
709 int can_proto_register(const struct can_proto *cp)
711 int proto = cp->protocol;
714 if (proto < 0 || proto >= CAN_NPROTO) {
715 printk(KERN_ERR "can: protocol number %d out of range\n",
720 err = proto_register(cp->prot, 0);
724 mutex_lock(&proto_tab_lock);
726 if (proto_tab[proto]) {
727 printk(KERN_ERR "can: protocol %d already registered\n",
731 RCU_INIT_POINTER(proto_tab[proto], cp);
733 mutex_unlock(&proto_tab_lock);
736 proto_unregister(cp->prot);
740 EXPORT_SYMBOL(can_proto_register);
743 * can_proto_unregister - unregister CAN transport protocol
744 * @cp: pointer to CAN protocol structure
746 void can_proto_unregister(const struct can_proto *cp)
748 int proto = cp->protocol;
750 mutex_lock(&proto_tab_lock);
751 BUG_ON(proto_tab[proto] != cp);
752 RCU_INIT_POINTER(proto_tab[proto], NULL);
753 mutex_unlock(&proto_tab_lock);
757 proto_unregister(cp->prot);
759 EXPORT_SYMBOL(can_proto_unregister);
762 * af_can notifier to create/remove CAN netdevice specific structs
764 static int can_notifier(struct notifier_block *nb, unsigned long msg,
767 struct net_device *dev = (struct net_device *)data;
768 struct dev_rcv_lists *d;
770 if (!net_eq(dev_net(dev), &init_net))
773 if (dev->type != ARPHRD_CAN)
778 case NETDEV_REGISTER:
780 /* create new dev_rcv_lists for this device */
781 d = kzalloc(sizeof(*d), GFP_KERNEL);
784 "can: allocation of receive list failed\n");
787 BUG_ON(dev->ml_priv);
792 case NETDEV_UNREGISTER:
793 spin_lock(&can_rcvlists_lock);
798 d->remove_on_zero_entries = 1;
804 printk(KERN_ERR "can: notifier: receive list not "
805 "found for dev %s\n", dev->name);
807 spin_unlock(&can_rcvlists_lock);
816 * af_can module init/exit functions
819 static struct packet_type can_packet __read_mostly = {
820 .type = cpu_to_be16(ETH_P_CAN),
825 static const struct net_proto_family can_family_ops = {
827 .create = can_create,
828 .owner = THIS_MODULE,
831 /* notifier block for netdevice event */
832 static struct notifier_block can_netdev_notifier __read_mostly = {
833 .notifier_call = can_notifier,
836 static __init int can_init(void)
840 memset(&can_rx_alldev_list, 0, sizeof(can_rx_alldev_list));
842 rcv_cache = kmem_cache_create("can_receiver", sizeof(struct receiver),
848 /* the statistics are updated every second (timer triggered) */
849 setup_timer(&can_stattimer, can_stat_update, 0);
850 mod_timer(&can_stattimer, round_jiffies(jiffies + HZ));
852 can_stattimer.function = NULL;
856 /* protocol register */
857 sock_register(&can_family_ops);
858 register_netdevice_notifier(&can_netdev_notifier);
859 dev_add_pack(&can_packet);
864 static __exit void can_exit(void)
866 struct net_device *dev;
869 del_timer_sync(&can_stattimer);
873 /* protocol unregister */
874 dev_remove_pack(&can_packet);
875 unregister_netdevice_notifier(&can_netdev_notifier);
876 sock_unregister(PF_CAN);
878 /* remove created dev_rcv_lists from still registered CAN devices */
880 for_each_netdev_rcu(&init_net, dev) {
881 if (dev->type == ARPHRD_CAN && dev->ml_priv){
883 struct dev_rcv_lists *d = dev->ml_priv;
892 rcu_barrier(); /* Wait for completion of call_rcu()'s */
894 kmem_cache_destroy(rcv_cache);
897 module_init(can_init);
898 module_exit(can_exit);