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_reset_network_header(skb
);
248 skb_reset_transport_header(skb
);
251 /* local loopback of sent CAN frames */
253 /* indication for the CAN driver: do loopback */
254 skb
->pkt_type
= PACKET_LOOPBACK
;
257 * The reference to the originating sock may be required
258 * by the receiving socket to check whether the frame is
259 * its own. Example: can_raw sockopt CAN_RAW_RECV_OWN_MSGS
260 * Therefore we have to ensure that skb->sk remains the
261 * reference to the originating sock by restoring skb->sk
262 * after each skb_clone() or skb_orphan() usage.
265 if (!(skb
->dev
->flags
& IFF_ECHO
)) {
267 * If the interface is not capable to do loopback
268 * itself, we do it here.
270 newskb
= skb_clone(skb
, GFP_ATOMIC
);
276 newskb
->sk
= skb
->sk
;
277 newskb
->ip_summed
= CHECKSUM_UNNECESSARY
;
278 newskb
->pkt_type
= PACKET_BROADCAST
;
281 /* indication for the CAN driver: no loopback required */
282 skb
->pkt_type
= PACKET_HOST
;
285 /* send to netdevice */
286 err
= dev_queue_xmit(skb
);
288 err
= net_xmit_errno(err
);
298 /* update statistics */
299 can_stats
.tx_frames
++;
300 can_stats
.tx_frames_delta
++;
304 EXPORT_SYMBOL(can_send
);
310 static struct dev_rcv_lists
*find_dev_rcv_lists(struct net_device
*dev
)
313 return &can_rx_alldev_list
;
315 return (struct dev_rcv_lists
*)dev
->ml_priv
;
319 * find_rcv_list - determine optimal filterlist inside device filter struct
320 * @can_id: pointer to CAN identifier of a given can_filter
321 * @mask: pointer to CAN mask of a given can_filter
322 * @d: pointer to the device filter struct
325 * Returns the optimal filterlist to reduce the filter handling in the
326 * receive path. This function is called by service functions that need
327 * to register or unregister a can_filter in the filter lists.
329 * A filter matches in general, when
331 * <received_can_id> & mask == can_id & mask
333 * so every bit set in the mask (even CAN_EFF_FLAG, CAN_RTR_FLAG) describe
334 * relevant bits for the filter.
336 * The filter can be inverted (CAN_INV_FILTER bit set in can_id) or it can
337 * filter for error frames (CAN_ERR_FLAG bit set in mask). For error frames
338 * there is a special filterlist and a special rx path filter handling.
341 * Pointer to optimal filterlist for the given can_id/mask pair.
342 * Constistency checked mask.
343 * Reduced can_id to have a preprocessed filter compare value.
345 static struct hlist_head
*find_rcv_list(canid_t
*can_id
, canid_t
*mask
,
346 struct dev_rcv_lists
*d
)
348 canid_t inv
= *can_id
& CAN_INV_FILTER
; /* save flag before masking */
350 /* filter for error frames in extra filterlist */
351 if (*mask
& CAN_ERR_FLAG
) {
352 /* clear CAN_ERR_FLAG in filter entry */
353 *mask
&= CAN_ERR_MASK
;
354 return &d
->rx
[RX_ERR
];
357 /* with cleared CAN_ERR_FLAG we have a simple mask/value filterpair */
359 #define CAN_EFF_RTR_FLAGS (CAN_EFF_FLAG | CAN_RTR_FLAG)
361 /* ensure valid values in can_mask for 'SFF only' frame filtering */
362 if ((*mask
& CAN_EFF_FLAG
) && !(*can_id
& CAN_EFF_FLAG
))
363 *mask
&= (CAN_SFF_MASK
| CAN_EFF_RTR_FLAGS
);
365 /* reduce condition testing at receive time */
368 /* inverse can_id/can_mask filter */
370 return &d
->rx
[RX_INV
];
372 /* mask == 0 => no condition testing at receive time */
374 return &d
->rx
[RX_ALL
];
376 /* extra filterlists for the subscription of a single non-RTR can_id */
377 if (((*mask
& CAN_EFF_RTR_FLAGS
) == CAN_EFF_RTR_FLAGS
) &&
378 !(*can_id
& CAN_RTR_FLAG
)) {
380 if (*can_id
& CAN_EFF_FLAG
) {
381 if (*mask
== (CAN_EFF_MASK
| CAN_EFF_RTR_FLAGS
)) {
382 /* RFC: a future use-case for hash-tables? */
383 return &d
->rx
[RX_EFF
];
386 if (*mask
== (CAN_SFF_MASK
| CAN_EFF_RTR_FLAGS
))
387 return &d
->rx_sff
[*can_id
];
391 /* default: filter via can_id/can_mask */
392 return &d
->rx
[RX_FIL
];
396 * can_rx_register - subscribe CAN frames from a specific interface
397 * @dev: pointer to netdevice (NULL => subcribe from 'all' CAN devices list)
398 * @can_id: CAN identifier (see description)
399 * @mask: CAN mask (see description)
400 * @func: callback function on filter match
401 * @data: returned parameter for callback function
402 * @ident: string for calling module indentification
405 * Invokes the callback function with the received sk_buff and the given
406 * parameter 'data' on a matching receive filter. A filter matches, when
408 * <received_can_id> & mask == can_id & mask
410 * The filter can be inverted (CAN_INV_FILTER bit set in can_id) or it can
411 * filter for error frames (CAN_ERR_FLAG bit set in mask).
413 * The provided pointer to the sk_buff is guaranteed to be valid as long as
414 * the callback function is running. The callback function must *not* free
415 * the given sk_buff while processing it's task. When the given sk_buff is
416 * needed after the end of the callback function it must be cloned inside
417 * the callback function with skb_clone().
421 * -ENOMEM on missing cache mem to create subscription entry
422 * -ENODEV unknown device
424 int can_rx_register(struct net_device
*dev
, canid_t can_id
, canid_t mask
,
425 void (*func
)(struct sk_buff
*, void *), void *data
,
429 struct hlist_head
*rl
;
430 struct dev_rcv_lists
*d
;
433 /* insert new receiver (dev,canid,mask) -> (func,data) */
435 if (dev
&& dev
->type
!= ARPHRD_CAN
)
438 r
= kmem_cache_alloc(rcv_cache
, GFP_KERNEL
);
442 spin_lock(&can_rcvlists_lock
);
444 d
= find_dev_rcv_lists(dev
);
446 rl
= find_rcv_list(&can_id
, &mask
, d
);
455 hlist_add_head_rcu(&r
->list
, rl
);
458 can_pstats
.rcv_entries
++;
459 if (can_pstats
.rcv_entries_max
< can_pstats
.rcv_entries
)
460 can_pstats
.rcv_entries_max
= can_pstats
.rcv_entries
;
462 kmem_cache_free(rcv_cache
, r
);
466 spin_unlock(&can_rcvlists_lock
);
470 EXPORT_SYMBOL(can_rx_register
);
473 * can_rx_delete_receiver - rcu callback for single receiver entry removal
475 static void can_rx_delete_receiver(struct rcu_head
*rp
)
477 struct receiver
*r
= container_of(rp
, struct receiver
, rcu
);
479 kmem_cache_free(rcv_cache
, r
);
483 * can_rx_unregister - unsubscribe CAN frames from a specific interface
484 * @dev: pointer to netdevice (NULL => unsubcribe from 'all' CAN devices list)
485 * @can_id: CAN identifier
487 * @func: callback function on filter match
488 * @data: returned parameter for callback function
491 * Removes subscription entry depending on given (subscription) values.
493 void can_rx_unregister(struct net_device
*dev
, canid_t can_id
, canid_t mask
,
494 void (*func
)(struct sk_buff
*, void *), void *data
)
496 struct receiver
*r
= NULL
;
497 struct hlist_head
*rl
;
498 struct hlist_node
*next
;
499 struct dev_rcv_lists
*d
;
501 if (dev
&& dev
->type
!= ARPHRD_CAN
)
504 spin_lock(&can_rcvlists_lock
);
506 d
= find_dev_rcv_lists(dev
);
508 printk(KERN_ERR
"BUG: receive list not found for "
509 "dev %s, id %03X, mask %03X\n",
510 DNAME(dev
), can_id
, mask
);
514 rl
= find_rcv_list(&can_id
, &mask
, d
);
517 * Search the receiver list for the item to delete. This should
518 * exist, since no receiver may be unregistered that hasn't
519 * been registered before.
522 hlist_for_each_entry_rcu(r
, next
, rl
, list
) {
523 if (r
->can_id
== can_id
&& r
->mask
== mask
&&
524 r
->func
== func
&& r
->data
== data
)
529 * Check for bugs in CAN protocol implementations:
530 * If no matching list item was found, the list cursor variable next
531 * will be NULL, while r will point to the last item of the list.
535 printk(KERN_ERR
"BUG: receive list entry not found for "
536 "dev %s, id %03X, mask %03X\n",
537 DNAME(dev
), can_id
, mask
);
542 hlist_del_rcu(&r
->list
);
545 if (can_pstats
.rcv_entries
> 0)
546 can_pstats
.rcv_entries
--;
548 /* remove device structure requested by NETDEV_UNREGISTER */
549 if (d
->remove_on_zero_entries
&& !d
->entries
) {
555 spin_unlock(&can_rcvlists_lock
);
557 /* schedule the receiver item for deletion */
559 call_rcu(&r
->rcu
, can_rx_delete_receiver
);
561 EXPORT_SYMBOL(can_rx_unregister
);
563 static inline void deliver(struct sk_buff
*skb
, struct receiver
*r
)
565 r
->func(skb
, r
->data
);
569 static int can_rcv_filter(struct dev_rcv_lists
*d
, struct sk_buff
*skb
)
572 struct hlist_node
*n
;
574 struct can_frame
*cf
= (struct can_frame
*)skb
->data
;
575 canid_t can_id
= cf
->can_id
;
580 if (can_id
& CAN_ERR_FLAG
) {
581 /* check for error frame entries only */
582 hlist_for_each_entry_rcu(r
, n
, &d
->rx
[RX_ERR
], list
) {
583 if (can_id
& r
->mask
) {
591 /* check for unfiltered entries */
592 hlist_for_each_entry_rcu(r
, n
, &d
->rx
[RX_ALL
], list
) {
597 /* check for can_id/mask entries */
598 hlist_for_each_entry_rcu(r
, n
, &d
->rx
[RX_FIL
], list
) {
599 if ((can_id
& r
->mask
) == r
->can_id
) {
605 /* check for inverted can_id/mask entries */
606 hlist_for_each_entry_rcu(r
, n
, &d
->rx
[RX_INV
], list
) {
607 if ((can_id
& r
->mask
) != r
->can_id
) {
613 /* check filterlists for single non-RTR can_ids */
614 if (can_id
& CAN_RTR_FLAG
)
617 if (can_id
& CAN_EFF_FLAG
) {
618 hlist_for_each_entry_rcu(r
, n
, &d
->rx
[RX_EFF
], list
) {
619 if (r
->can_id
== can_id
) {
625 can_id
&= CAN_SFF_MASK
;
626 hlist_for_each_entry_rcu(r
, n
, &d
->rx_sff
[can_id
], list
) {
635 static int can_rcv(struct sk_buff
*skb
, struct net_device
*dev
,
636 struct packet_type
*pt
, struct net_device
*orig_dev
)
638 struct dev_rcv_lists
*d
;
639 struct can_frame
*cf
= (struct can_frame
*)skb
->data
;
642 if (!net_eq(dev_net(dev
), &init_net
))
645 if (WARN_ONCE(dev
->type
!= ARPHRD_CAN
||
646 skb
->len
!= sizeof(struct can_frame
) ||
648 "PF_CAN: dropped non conform skbuf: "
649 "dev type %d, len %d, can_dlc %d\n",
650 dev
->type
, skb
->len
, cf
->can_dlc
))
653 /* update statistics */
654 can_stats
.rx_frames
++;
655 can_stats
.rx_frames_delta
++;
659 /* deliver the packet to sockets listening on all devices */
660 matches
= can_rcv_filter(&can_rx_alldev_list
, skb
);
662 /* find receive list for this device */
663 d
= find_dev_rcv_lists(dev
);
665 matches
+= can_rcv_filter(d
, skb
);
669 /* consume the skbuff allocated by the netdevice driver */
674 can_stats
.matches_delta
++;
677 return NET_RX_SUCCESS
;
685 * af_can protocol functions
689 * can_proto_register - register CAN transport protocol
690 * @cp: pointer to CAN protocol structure
694 * -EINVAL invalid (out of range) protocol number
695 * -EBUSY protocol already in use
696 * -ENOBUF if proto_register() fails
698 int can_proto_register(const struct can_proto
*cp
)
700 int proto
= cp
->protocol
;
703 if (proto
< 0 || proto
>= CAN_NPROTO
) {
704 printk(KERN_ERR
"can: protocol number %d out of range\n",
709 err
= proto_register(cp
->prot
, 0);
713 mutex_lock(&proto_tab_lock
);
715 if (proto_tab
[proto
]) {
716 printk(KERN_ERR
"can: protocol %d already registered\n",
720 RCU_INIT_POINTER(proto_tab
[proto
], cp
);
722 mutex_unlock(&proto_tab_lock
);
725 proto_unregister(cp
->prot
);
729 EXPORT_SYMBOL(can_proto_register
);
732 * can_proto_unregister - unregister CAN transport protocol
733 * @cp: pointer to CAN protocol structure
735 void can_proto_unregister(const struct can_proto
*cp
)
737 int proto
= cp
->protocol
;
739 mutex_lock(&proto_tab_lock
);
740 BUG_ON(proto_tab
[proto
] != cp
);
741 RCU_INIT_POINTER(proto_tab
[proto
], NULL
);
742 mutex_unlock(&proto_tab_lock
);
746 proto_unregister(cp
->prot
);
748 EXPORT_SYMBOL(can_proto_unregister
);
751 * af_can notifier to create/remove CAN netdevice specific structs
753 static int can_notifier(struct notifier_block
*nb
, unsigned long msg
,
756 struct net_device
*dev
= (struct net_device
*)data
;
757 struct dev_rcv_lists
*d
;
759 if (!net_eq(dev_net(dev
), &init_net
))
762 if (dev
->type
!= ARPHRD_CAN
)
767 case NETDEV_REGISTER
:
769 /* create new dev_rcv_lists for this device */
770 d
= kzalloc(sizeof(*d
), GFP_KERNEL
);
773 "can: allocation of receive list failed\n");
776 BUG_ON(dev
->ml_priv
);
781 case NETDEV_UNREGISTER
:
782 spin_lock(&can_rcvlists_lock
);
787 d
->remove_on_zero_entries
= 1;
793 printk(KERN_ERR
"can: notifier: receive list not "
794 "found for dev %s\n", dev
->name
);
796 spin_unlock(&can_rcvlists_lock
);
805 * af_can module init/exit functions
808 static struct packet_type can_packet __read_mostly
= {
809 .type
= cpu_to_be16(ETH_P_CAN
),
814 static const struct net_proto_family can_family_ops
= {
816 .create
= can_create
,
817 .owner
= THIS_MODULE
,
820 /* notifier block for netdevice event */
821 static struct notifier_block can_netdev_notifier __read_mostly
= {
822 .notifier_call
= can_notifier
,
825 static __init
int can_init(void)
829 memset(&can_rx_alldev_list
, 0, sizeof(can_rx_alldev_list
));
831 rcv_cache
= kmem_cache_create("can_receiver", sizeof(struct receiver
),
837 /* the statistics are updated every second (timer triggered) */
838 setup_timer(&can_stattimer
, can_stat_update
, 0);
839 mod_timer(&can_stattimer
, round_jiffies(jiffies
+ HZ
));
841 can_stattimer
.function
= NULL
;
845 /* protocol register */
846 sock_register(&can_family_ops
);
847 register_netdevice_notifier(&can_netdev_notifier
);
848 dev_add_pack(&can_packet
);
853 static __exit
void can_exit(void)
855 struct net_device
*dev
;
858 del_timer_sync(&can_stattimer
);
862 /* protocol unregister */
863 dev_remove_pack(&can_packet
);
864 unregister_netdevice_notifier(&can_netdev_notifier
);
865 sock_unregister(PF_CAN
);
867 /* remove created dev_rcv_lists from still registered CAN devices */
869 for_each_netdev_rcu(&init_net
, dev
) {
870 if (dev
->type
== ARPHRD_CAN
&& dev
->ml_priv
){
872 struct dev_rcv_lists
*d
= dev
->ml_priv
;
881 rcu_barrier(); /* Wait for completion of call_rcu()'s */
883 kmem_cache_destroy(rcv_cache
);
886 module_init(can_init
);
887 module_exit(can_exit
);