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
41 * Send feedback to <socketcan-users@lists.berlios.de>
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 <net/net_namespace.h>
66 static __initdata const char banner[] = KERN_INFO
67 "can: controller area network core (" CAN_VERSION_STRING ")\n";
69 MODULE_DESCRIPTION("Controller Area Network PF_CAN core");
70 MODULE_LICENSE("Dual BSD/GPL");
71 MODULE_AUTHOR("Urs Thuermann <urs.thuermann@volkswagen.de>, "
72 "Oliver Hartkopp <oliver.hartkopp@volkswagen.de>");
74 MODULE_ALIAS_NETPROTO(PF_CAN);
76 static int stats_timer __read_mostly = 1;
77 module_param(stats_timer, int, S_IRUGO);
78 MODULE_PARM_DESC(stats_timer, "enable timer for statistics (default:on)");
80 /* receive filters subscribed for 'all' CAN devices */
81 struct dev_rcv_lists can_rx_alldev_list;
82 static DEFINE_SPINLOCK(can_rcvlists_lock);
84 static struct kmem_cache *rcv_cache __read_mostly;
86 /* table of registered CAN protocols */
87 static const struct can_proto *proto_tab[CAN_NPROTO] __read_mostly;
88 static DEFINE_MUTEX(proto_tab_lock);
90 struct timer_list can_stattimer; /* timer for statistics update */
91 struct s_stats can_stats; /* packet statistics */
92 struct s_pstats can_pstats; /* receive list statistics */
95 * af_can socket functions
98 int can_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
100 struct sock *sk = sock->sk;
105 return sock_get_timestamp(sk, (struct timeval __user *)arg);
111 EXPORT_SYMBOL(can_ioctl);
113 static void can_sock_destruct(struct sock *sk)
115 skb_queue_purge(&sk->sk_receive_queue);
118 static const struct can_proto *can_get_proto(int protocol)
120 const struct can_proto *cp;
123 cp = rcu_dereference(proto_tab[protocol]);
124 if (cp && !try_module_get(cp->prot->owner))
131 static inline void can_put_proto(const struct can_proto *cp)
133 module_put(cp->prot->owner);
136 static int can_create(struct net *net, struct socket *sock, int protocol,
140 const struct can_proto *cp;
143 sock->state = SS_UNCONNECTED;
145 if (protocol < 0 || protocol >= CAN_NPROTO)
148 if (!net_eq(net, &init_net))
149 return -EAFNOSUPPORT;
151 cp = can_get_proto(protocol);
153 #ifdef CONFIG_MODULES
155 /* try to load protocol module if kernel is modular */
157 err = request_module("can-proto-%d", protocol);
160 * In case of error we only print a message but don't
161 * return the error code immediately. Below we will
162 * return -EPROTONOSUPPORT
164 if (err && printk_ratelimit())
165 printk(KERN_ERR "can: request_module "
166 "(can-proto-%d) failed.\n", protocol);
168 cp = can_get_proto(protocol);
172 /* check for available protocol and correct usage */
175 return -EPROTONOSUPPORT;
177 if (cp->type != sock->type) {
184 sk = sk_alloc(net, PF_CAN, GFP_KERNEL, cp->prot);
190 sock_init_data(sock, sk);
191 sk->sk_destruct = can_sock_destruct;
193 if (sk->sk_prot->init)
194 err = sk->sk_prot->init(sk);
197 /* release sk on errors */
212 * can_send - transmit a CAN frame (optional with local loopback)
213 * @skb: pointer to socket buffer with CAN frame in data section
214 * @loop: loopback for listeners on local CAN sockets (recommended default!)
216 * Due to the loopback this routine must not be called from hardirq context.
220 * -ENETDOWN when the selected interface is down
221 * -ENOBUFS on full driver queue (see net_xmit_errno())
222 * -ENOMEM when local loopback failed at calling skb_clone()
223 * -EPERM when trying to send on a non-CAN interface
224 * -EINVAL when the skb->data does not contain a valid CAN frame
226 int can_send(struct sk_buff *skb, int loop)
228 struct sk_buff *newskb = NULL;
229 struct can_frame *cf = (struct can_frame *)skb->data;
232 if (skb->len != sizeof(struct can_frame) || cf->can_dlc > 8) {
237 if (skb->dev->type != ARPHRD_CAN) {
242 if (!(skb->dev->flags & IFF_UP)) {
247 skb->protocol = htons(ETH_P_CAN);
248 skb_reset_network_header(skb);
249 skb_reset_transport_header(skb);
252 /* local loopback of sent CAN frames */
254 /* indication for the CAN driver: do loopback */
255 skb->pkt_type = PACKET_LOOPBACK;
258 * The reference to the originating sock may be required
259 * by the receiving socket to check whether the frame is
260 * its own. Example: can_raw sockopt CAN_RAW_RECV_OWN_MSGS
261 * Therefore we have to ensure that skb->sk remains the
262 * reference to the originating sock by restoring skb->sk
263 * after each skb_clone() or skb_orphan() usage.
266 if (!(skb->dev->flags & IFF_ECHO)) {
268 * If the interface is not capable to do loopback
269 * itself, we do it here.
271 newskb = skb_clone(skb, GFP_ATOMIC);
277 newskb->sk = skb->sk;
278 newskb->ip_summed = CHECKSUM_UNNECESSARY;
279 newskb->pkt_type = PACKET_BROADCAST;
282 /* indication for the CAN driver: no loopback required */
283 skb->pkt_type = PACKET_HOST;
286 /* send to netdevice */
287 err = dev_queue_xmit(skb);
289 err = net_xmit_errno(err);
299 /* update statistics */
300 can_stats.tx_frames++;
301 can_stats.tx_frames_delta++;
305 EXPORT_SYMBOL(can_send);
311 static struct dev_rcv_lists *find_dev_rcv_lists(struct net_device *dev)
314 return &can_rx_alldev_list;
316 return (struct dev_rcv_lists *)dev->ml_priv;
320 * find_rcv_list - determine optimal filterlist inside device filter struct
321 * @can_id: pointer to CAN identifier of a given can_filter
322 * @mask: pointer to CAN mask of a given can_filter
323 * @d: pointer to the device filter struct
326 * Returns the optimal filterlist to reduce the filter handling in the
327 * receive path. This function is called by service functions that need
328 * to register or unregister a can_filter in the filter lists.
330 * A filter matches in general, when
332 * <received_can_id> & mask == can_id & mask
334 * so every bit set in the mask (even CAN_EFF_FLAG, CAN_RTR_FLAG) describe
335 * relevant bits for the filter.
337 * The filter can be inverted (CAN_INV_FILTER bit set in can_id) or it can
338 * filter for error frames (CAN_ERR_FLAG bit set in mask). For error frames
339 * there is a special filterlist and a special rx path filter handling.
342 * Pointer to optimal filterlist for the given can_id/mask pair.
343 * Constistency checked mask.
344 * Reduced can_id to have a preprocessed filter compare value.
346 static struct hlist_head *find_rcv_list(canid_t *can_id, canid_t *mask,
347 struct dev_rcv_lists *d)
349 canid_t inv = *can_id & CAN_INV_FILTER; /* save flag before masking */
351 /* filter for error frames in extra filterlist */
352 if (*mask & CAN_ERR_FLAG) {
353 /* clear CAN_ERR_FLAG in filter entry */
354 *mask &= CAN_ERR_MASK;
355 return &d->rx[RX_ERR];
358 /* with cleared CAN_ERR_FLAG we have a simple mask/value filterpair */
360 #define CAN_EFF_RTR_FLAGS (CAN_EFF_FLAG | CAN_RTR_FLAG)
362 /* ensure valid values in can_mask for 'SFF only' frame filtering */
363 if ((*mask & CAN_EFF_FLAG) && !(*can_id & CAN_EFF_FLAG))
364 *mask &= (CAN_SFF_MASK | CAN_EFF_RTR_FLAGS);
366 /* reduce condition testing at receive time */
369 /* inverse can_id/can_mask filter */
371 return &d->rx[RX_INV];
373 /* mask == 0 => no condition testing at receive time */
375 return &d->rx[RX_ALL];
377 /* extra filterlists for the subscription of a single non-RTR can_id */
378 if (((*mask & CAN_EFF_RTR_FLAGS) == CAN_EFF_RTR_FLAGS) &&
379 !(*can_id & CAN_RTR_FLAG)) {
381 if (*can_id & CAN_EFF_FLAG) {
382 if (*mask == (CAN_EFF_MASK | CAN_EFF_RTR_FLAGS)) {
383 /* RFC: a future use-case for hash-tables? */
384 return &d->rx[RX_EFF];
387 if (*mask == (CAN_SFF_MASK | CAN_EFF_RTR_FLAGS))
388 return &d->rx_sff[*can_id];
392 /* default: filter via can_id/can_mask */
393 return &d->rx[RX_FIL];
397 * can_rx_register - subscribe CAN frames from a specific interface
398 * @dev: pointer to netdevice (NULL => subcribe from 'all' CAN devices list)
399 * @can_id: CAN identifier (see description)
400 * @mask: CAN mask (see description)
401 * @func: callback function on filter match
402 * @data: returned parameter for callback function
403 * @ident: string for calling module indentification
406 * Invokes the callback function with the received sk_buff and the given
407 * parameter 'data' on a matching receive filter. A filter matches, when
409 * <received_can_id> & mask == can_id & mask
411 * The filter can be inverted (CAN_INV_FILTER bit set in can_id) or it can
412 * filter for error frames (CAN_ERR_FLAG bit set in mask).
414 * The provided pointer to the sk_buff is guaranteed to be valid as long as
415 * the callback function is running. The callback function must *not* free
416 * the given sk_buff while processing it's task. When the given sk_buff is
417 * needed after the end of the callback function it must be cloned inside
418 * the callback function with skb_clone().
422 * -ENOMEM on missing cache mem to create subscription entry
423 * -ENODEV unknown device
425 int can_rx_register(struct net_device *dev, canid_t can_id, canid_t mask,
426 void (*func)(struct sk_buff *, void *), void *data,
430 struct hlist_head *rl;
431 struct dev_rcv_lists *d;
434 /* insert new receiver (dev,canid,mask) -> (func,data) */
436 if (dev && dev->type != ARPHRD_CAN)
439 r = kmem_cache_alloc(rcv_cache, GFP_KERNEL);
443 spin_lock(&can_rcvlists_lock);
445 d = find_dev_rcv_lists(dev);
447 rl = find_rcv_list(&can_id, &mask, d);
456 hlist_add_head_rcu(&r->list, rl);
459 can_pstats.rcv_entries++;
460 if (can_pstats.rcv_entries_max < can_pstats.rcv_entries)
461 can_pstats.rcv_entries_max = can_pstats.rcv_entries;
463 kmem_cache_free(rcv_cache, r);
467 spin_unlock(&can_rcvlists_lock);
471 EXPORT_SYMBOL(can_rx_register);
474 * can_rx_delete_receiver - rcu callback for single receiver entry removal
476 static void can_rx_delete_receiver(struct rcu_head *rp)
478 struct receiver *r = container_of(rp, struct receiver, rcu);
480 kmem_cache_free(rcv_cache, r);
484 * can_rx_unregister - unsubscribe CAN frames from a specific interface
485 * @dev: pointer to netdevice (NULL => unsubcribe from 'all' CAN devices list)
486 * @can_id: CAN identifier
488 * @func: callback function on filter match
489 * @data: returned parameter for callback function
492 * Removes subscription entry depending on given (subscription) values.
494 void can_rx_unregister(struct net_device *dev, canid_t can_id, canid_t mask,
495 void (*func)(struct sk_buff *, void *), void *data)
497 struct receiver *r = NULL;
498 struct hlist_head *rl;
499 struct hlist_node *next;
500 struct dev_rcv_lists *d;
502 if (dev && dev->type != ARPHRD_CAN)
505 spin_lock(&can_rcvlists_lock);
507 d = find_dev_rcv_lists(dev);
509 printk(KERN_ERR "BUG: receive list not found for "
510 "dev %s, id %03X, mask %03X\n",
511 DNAME(dev), can_id, mask);
515 rl = find_rcv_list(&can_id, &mask, d);
518 * Search the receiver list for the item to delete. This should
519 * exist, since no receiver may be unregistered that hasn't
520 * been registered before.
523 hlist_for_each_entry_rcu(r, next, rl, list) {
524 if (r->can_id == can_id && r->mask == mask &&
525 r->func == func && r->data == data)
530 * Check for bugs in CAN protocol implementations:
531 * If no matching list item was found, the list cursor variable next
532 * will be NULL, while r will point to the last item of the list.
536 printk(KERN_ERR "BUG: receive list entry not found for "
537 "dev %s, id %03X, mask %03X\n",
538 DNAME(dev), can_id, mask);
543 hlist_del_rcu(&r->list);
546 if (can_pstats.rcv_entries > 0)
547 can_pstats.rcv_entries--;
549 /* remove device structure requested by NETDEV_UNREGISTER */
550 if (d->remove_on_zero_entries && !d->entries) {
556 spin_unlock(&can_rcvlists_lock);
558 /* schedule the receiver item for deletion */
560 call_rcu(&r->rcu, can_rx_delete_receiver);
562 EXPORT_SYMBOL(can_rx_unregister);
564 static inline void deliver(struct sk_buff *skb, struct receiver *r)
566 r->func(skb, r->data);
570 static int can_rcv_filter(struct dev_rcv_lists *d, struct sk_buff *skb)
573 struct hlist_node *n;
575 struct can_frame *cf = (struct can_frame *)skb->data;
576 canid_t can_id = cf->can_id;
581 if (can_id & CAN_ERR_FLAG) {
582 /* check for error frame entries only */
583 hlist_for_each_entry_rcu(r, n, &d->rx[RX_ERR], list) {
584 if (can_id & r->mask) {
592 /* check for unfiltered entries */
593 hlist_for_each_entry_rcu(r, n, &d->rx[RX_ALL], list) {
598 /* check for can_id/mask entries */
599 hlist_for_each_entry_rcu(r, n, &d->rx[RX_FIL], list) {
600 if ((can_id & r->mask) == r->can_id) {
606 /* check for inverted can_id/mask entries */
607 hlist_for_each_entry_rcu(r, n, &d->rx[RX_INV], list) {
608 if ((can_id & r->mask) != r->can_id) {
614 /* check filterlists for single non-RTR can_ids */
615 if (can_id & CAN_RTR_FLAG)
618 if (can_id & CAN_EFF_FLAG) {
619 hlist_for_each_entry_rcu(r, n, &d->rx[RX_EFF], list) {
620 if (r->can_id == can_id) {
626 can_id &= CAN_SFF_MASK;
627 hlist_for_each_entry_rcu(r, n, &d->rx_sff[can_id], list) {
636 static int can_rcv(struct sk_buff *skb, struct net_device *dev,
637 struct packet_type *pt, struct net_device *orig_dev)
639 struct dev_rcv_lists *d;
640 struct can_frame *cf = (struct can_frame *)skb->data;
643 if (!net_eq(dev_net(dev), &init_net))
646 if (WARN_ONCE(dev->type != ARPHRD_CAN ||
647 skb->len != sizeof(struct can_frame) ||
649 "PF_CAN: dropped non conform skbuf: "
650 "dev type %d, len %d, can_dlc %d\n",
651 dev->type, skb->len, cf->can_dlc))
654 /* update statistics */
655 can_stats.rx_frames++;
656 can_stats.rx_frames_delta++;
660 /* deliver the packet to sockets listening on all devices */
661 matches = can_rcv_filter(&can_rx_alldev_list, skb);
663 /* find receive list for this device */
664 d = find_dev_rcv_lists(dev);
666 matches += can_rcv_filter(d, skb);
670 /* consume the skbuff allocated by the netdevice driver */
675 can_stats.matches_delta++;
678 return NET_RX_SUCCESS;
686 * af_can protocol functions
690 * can_proto_register - register CAN transport protocol
691 * @cp: pointer to CAN protocol structure
695 * -EINVAL invalid (out of range) protocol number
696 * -EBUSY protocol already in use
697 * -ENOBUF if proto_register() fails
699 int can_proto_register(const struct can_proto *cp)
701 int proto = cp->protocol;
704 if (proto < 0 || proto >= CAN_NPROTO) {
705 printk(KERN_ERR "can: protocol number %d out of range\n",
710 err = proto_register(cp->prot, 0);
714 mutex_lock(&proto_tab_lock);
716 if (proto_tab[proto]) {
717 printk(KERN_ERR "can: protocol %d already registered\n",
721 rcu_assign_pointer(proto_tab[proto], cp);
723 mutex_unlock(&proto_tab_lock);
726 proto_unregister(cp->prot);
730 EXPORT_SYMBOL(can_proto_register);
733 * can_proto_unregister - unregister CAN transport protocol
734 * @cp: pointer to CAN protocol structure
736 void can_proto_unregister(const struct can_proto *cp)
738 int proto = cp->protocol;
740 mutex_lock(&proto_tab_lock);
741 BUG_ON(proto_tab[proto] != cp);
742 rcu_assign_pointer(proto_tab[proto], NULL);
743 mutex_unlock(&proto_tab_lock);
747 proto_unregister(cp->prot);
749 EXPORT_SYMBOL(can_proto_unregister);
752 * af_can notifier to create/remove CAN netdevice specific structs
754 static int can_notifier(struct notifier_block *nb, unsigned long msg,
757 struct net_device *dev = (struct net_device *)data;
758 struct dev_rcv_lists *d;
760 if (!net_eq(dev_net(dev), &init_net))
763 if (dev->type != ARPHRD_CAN)
768 case NETDEV_REGISTER:
770 /* create new dev_rcv_lists for this device */
771 d = kzalloc(sizeof(*d), GFP_KERNEL);
774 "can: allocation of receive list failed\n");
777 BUG_ON(dev->ml_priv);
782 case NETDEV_UNREGISTER:
783 spin_lock(&can_rcvlists_lock);
788 d->remove_on_zero_entries = 1;
794 printk(KERN_ERR "can: notifier: receive list not "
795 "found for dev %s\n", dev->name);
797 spin_unlock(&can_rcvlists_lock);
806 * af_can module init/exit functions
809 static struct packet_type can_packet __read_mostly = {
810 .type = cpu_to_be16(ETH_P_CAN),
815 static const struct net_proto_family can_family_ops = {
817 .create = can_create,
818 .owner = THIS_MODULE,
821 /* notifier block for netdevice event */
822 static struct notifier_block can_netdev_notifier __read_mostly = {
823 .notifier_call = can_notifier,
826 static __init int can_init(void)
830 memset(&can_rx_alldev_list, 0, sizeof(can_rx_alldev_list));
832 rcv_cache = kmem_cache_create("can_receiver", sizeof(struct receiver),
838 /* the statistics are updated every second (timer triggered) */
839 setup_timer(&can_stattimer, can_stat_update, 0);
840 mod_timer(&can_stattimer, round_jiffies(jiffies + HZ));
842 can_stattimer.function = NULL;
846 /* protocol register */
847 sock_register(&can_family_ops);
848 register_netdevice_notifier(&can_netdev_notifier);
849 dev_add_pack(&can_packet);
854 static __exit void can_exit(void)
856 struct net_device *dev;
859 del_timer(&can_stattimer);
863 /* protocol unregister */
864 dev_remove_pack(&can_packet);
865 unregister_netdevice_notifier(&can_netdev_notifier);
866 sock_unregister(PF_CAN);
868 /* remove created dev_rcv_lists from still registered CAN devices */
870 for_each_netdev_rcu(&init_net, dev) {
871 if (dev->type == ARPHRD_CAN && dev->ml_priv){
873 struct dev_rcv_lists *d = dev->ml_priv;
882 rcu_barrier(); /* Wait for completion of call_rcu()'s */
884 kmem_cache_destroy(rcv_cache);
887 module_init(can_init);
888 module_exit(can_exit);