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 struct can_proto
*proto_tab
[CAN_NPROTO
] __read_mostly
;
88 static DEFINE_SPINLOCK(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 int can_create(struct net
*net
, struct socket
*sock
, int protocol
,
122 struct can_proto
*cp
;
125 sock
->state
= SS_UNCONNECTED
;
127 if (protocol
< 0 || protocol
>= CAN_NPROTO
)
130 if (!net_eq(net
, &init_net
))
131 return -EAFNOSUPPORT
;
133 #ifdef CONFIG_MODULES
134 /* try to load protocol module kernel is modular */
135 if (!proto_tab
[protocol
]) {
136 err
= request_module("can-proto-%d", protocol
);
139 * In case of error we only print a message but don't
140 * return the error code immediately. Below we will
141 * return -EPROTONOSUPPORT
143 if (err
&& printk_ratelimit())
144 printk(KERN_ERR
"can: request_module "
145 "(can-proto-%d) failed.\n", protocol
);
149 spin_lock(&proto_tab_lock
);
150 cp
= proto_tab
[protocol
];
151 if (cp
&& !try_module_get(cp
->prot
->owner
))
153 spin_unlock(&proto_tab_lock
);
155 /* check for available protocol and correct usage */
158 return -EPROTONOSUPPORT
;
160 if (cp
->type
!= sock
->type
) {
161 err
= -EPROTONOSUPPORT
;
167 sk
= sk_alloc(net
, PF_CAN
, GFP_KERNEL
, cp
->prot
);
173 sock_init_data(sock
, sk
);
174 sk
->sk_destruct
= can_sock_destruct
;
176 if (sk
->sk_prot
->init
)
177 err
= sk
->sk_prot
->init(sk
);
180 /* release sk on errors */
186 module_put(cp
->prot
->owner
);
195 * can_send - transmit a CAN frame (optional with local loopback)
196 * @skb: pointer to socket buffer with CAN frame in data section
197 * @loop: loopback for listeners on local CAN sockets (recommended default!)
199 * Due to the loopback this routine must not be called from hardirq context.
203 * -ENETDOWN when the selected interface is down
204 * -ENOBUFS on full driver queue (see net_xmit_errno())
205 * -ENOMEM when local loopback failed at calling skb_clone()
206 * -EPERM when trying to send on a non-CAN interface
207 * -EINVAL when the skb->data does not contain a valid CAN frame
209 int can_send(struct sk_buff
*skb
, int loop
)
211 struct sk_buff
*newskb
= NULL
;
212 struct can_frame
*cf
= (struct can_frame
*)skb
->data
;
215 if (skb
->len
!= sizeof(struct can_frame
) || cf
->can_dlc
> 8) {
220 if (skb
->dev
->type
!= ARPHRD_CAN
) {
225 if (!(skb
->dev
->flags
& IFF_UP
)) {
230 skb
->protocol
= htons(ETH_P_CAN
);
231 skb_reset_network_header(skb
);
232 skb_reset_transport_header(skb
);
235 /* local loopback of sent CAN frames */
237 /* indication for the CAN driver: do loopback */
238 skb
->pkt_type
= PACKET_LOOPBACK
;
241 * The reference to the originating sock may be required
242 * by the receiving socket to check whether the frame is
243 * its own. Example: can_raw sockopt CAN_RAW_RECV_OWN_MSGS
244 * Therefore we have to ensure that skb->sk remains the
245 * reference to the originating sock by restoring skb->sk
246 * after each skb_clone() or skb_orphan() usage.
249 if (!(skb
->dev
->flags
& IFF_ECHO
)) {
251 * If the interface is not capable to do loopback
252 * itself, we do it here.
254 newskb
= skb_clone(skb
, GFP_ATOMIC
);
260 newskb
->sk
= skb
->sk
;
261 newskb
->ip_summed
= CHECKSUM_UNNECESSARY
;
262 newskb
->pkt_type
= PACKET_BROADCAST
;
265 /* indication for the CAN driver: no loopback required */
266 skb
->pkt_type
= PACKET_HOST
;
269 /* send to netdevice */
270 err
= dev_queue_xmit(skb
);
272 err
= net_xmit_errno(err
);
282 /* update statistics */
283 can_stats
.tx_frames
++;
284 can_stats
.tx_frames_delta
++;
288 EXPORT_SYMBOL(can_send
);
294 static struct dev_rcv_lists
*find_dev_rcv_lists(struct net_device
*dev
)
297 return &can_rx_alldev_list
;
299 return (struct dev_rcv_lists
*)dev
->ml_priv
;
303 * find_rcv_list - determine optimal filterlist inside device filter struct
304 * @can_id: pointer to CAN identifier of a given can_filter
305 * @mask: pointer to CAN mask of a given can_filter
306 * @d: pointer to the device filter struct
309 * Returns the optimal filterlist to reduce the filter handling in the
310 * receive path. This function is called by service functions that need
311 * to register or unregister a can_filter in the filter lists.
313 * A filter matches in general, when
315 * <received_can_id> & mask == can_id & mask
317 * so every bit set in the mask (even CAN_EFF_FLAG, CAN_RTR_FLAG) describe
318 * relevant bits for the filter.
320 * The filter can be inverted (CAN_INV_FILTER bit set in can_id) or it can
321 * filter for error frames (CAN_ERR_FLAG bit set in mask). For error frames
322 * there is a special filterlist and a special rx path filter handling.
325 * Pointer to optimal filterlist for the given can_id/mask pair.
326 * Constistency checked mask.
327 * Reduced can_id to have a preprocessed filter compare value.
329 static struct hlist_head
*find_rcv_list(canid_t
*can_id
, canid_t
*mask
,
330 struct dev_rcv_lists
*d
)
332 canid_t inv
= *can_id
& CAN_INV_FILTER
; /* save flag before masking */
334 /* filter for error frames in extra filterlist */
335 if (*mask
& CAN_ERR_FLAG
) {
336 /* clear CAN_ERR_FLAG in filter entry */
337 *mask
&= CAN_ERR_MASK
;
338 return &d
->rx
[RX_ERR
];
341 /* with cleared CAN_ERR_FLAG we have a simple mask/value filterpair */
343 #define CAN_EFF_RTR_FLAGS (CAN_EFF_FLAG | CAN_RTR_FLAG)
345 /* ensure valid values in can_mask for 'SFF only' frame filtering */
346 if ((*mask
& CAN_EFF_FLAG
) && !(*can_id
& CAN_EFF_FLAG
))
347 *mask
&= (CAN_SFF_MASK
| CAN_EFF_RTR_FLAGS
);
349 /* reduce condition testing at receive time */
352 /* inverse can_id/can_mask filter */
354 return &d
->rx
[RX_INV
];
356 /* mask == 0 => no condition testing at receive time */
358 return &d
->rx
[RX_ALL
];
360 /* extra filterlists for the subscription of a single non-RTR can_id */
361 if (((*mask
& CAN_EFF_RTR_FLAGS
) == CAN_EFF_RTR_FLAGS
) &&
362 !(*can_id
& CAN_RTR_FLAG
)) {
364 if (*can_id
& CAN_EFF_FLAG
) {
365 if (*mask
== (CAN_EFF_MASK
| CAN_EFF_RTR_FLAGS
)) {
366 /* RFC: a future use-case for hash-tables? */
367 return &d
->rx
[RX_EFF
];
370 if (*mask
== (CAN_SFF_MASK
| CAN_EFF_RTR_FLAGS
))
371 return &d
->rx_sff
[*can_id
];
375 /* default: filter via can_id/can_mask */
376 return &d
->rx
[RX_FIL
];
380 * can_rx_register - subscribe CAN frames from a specific interface
381 * @dev: pointer to netdevice (NULL => subcribe from 'all' CAN devices list)
382 * @can_id: CAN identifier (see description)
383 * @mask: CAN mask (see description)
384 * @func: callback function on filter match
385 * @data: returned parameter for callback function
386 * @ident: string for calling module indentification
389 * Invokes the callback function with the received sk_buff and the given
390 * parameter 'data' on a matching receive filter. A filter matches, when
392 * <received_can_id> & mask == can_id & mask
394 * The filter can be inverted (CAN_INV_FILTER bit set in can_id) or it can
395 * filter for error frames (CAN_ERR_FLAG bit set in mask).
397 * The provided pointer to the sk_buff is guaranteed to be valid as long as
398 * the callback function is running. The callback function must *not* free
399 * the given sk_buff while processing it's task. When the given sk_buff is
400 * needed after the end of the callback function it must be cloned inside
401 * the callback function with skb_clone().
405 * -ENOMEM on missing cache mem to create subscription entry
406 * -ENODEV unknown device
408 int can_rx_register(struct net_device
*dev
, canid_t can_id
, canid_t mask
,
409 void (*func
)(struct sk_buff
*, void *), void *data
,
413 struct hlist_head
*rl
;
414 struct dev_rcv_lists
*d
;
417 /* insert new receiver (dev,canid,mask) -> (func,data) */
419 if (dev
&& dev
->type
!= ARPHRD_CAN
)
422 r
= kmem_cache_alloc(rcv_cache
, GFP_KERNEL
);
426 spin_lock(&can_rcvlists_lock
);
428 d
= find_dev_rcv_lists(dev
);
430 rl
= find_rcv_list(&can_id
, &mask
, d
);
439 hlist_add_head_rcu(&r
->list
, rl
);
442 can_pstats
.rcv_entries
++;
443 if (can_pstats
.rcv_entries_max
< can_pstats
.rcv_entries
)
444 can_pstats
.rcv_entries_max
= can_pstats
.rcv_entries
;
446 kmem_cache_free(rcv_cache
, r
);
450 spin_unlock(&can_rcvlists_lock
);
454 EXPORT_SYMBOL(can_rx_register
);
457 * can_rx_delete_receiver - rcu callback for single receiver entry removal
459 static void can_rx_delete_receiver(struct rcu_head
*rp
)
461 struct receiver
*r
= container_of(rp
, struct receiver
, rcu
);
463 kmem_cache_free(rcv_cache
, r
);
467 * can_rx_unregister - unsubscribe CAN frames from a specific interface
468 * @dev: pointer to netdevice (NULL => unsubcribe from 'all' CAN devices list)
469 * @can_id: CAN identifier
471 * @func: callback function on filter match
472 * @data: returned parameter for callback function
475 * Removes subscription entry depending on given (subscription) values.
477 void can_rx_unregister(struct net_device
*dev
, canid_t can_id
, canid_t mask
,
478 void (*func
)(struct sk_buff
*, void *), void *data
)
480 struct receiver
*r
= NULL
;
481 struct hlist_head
*rl
;
482 struct hlist_node
*next
;
483 struct dev_rcv_lists
*d
;
485 if (dev
&& dev
->type
!= ARPHRD_CAN
)
488 spin_lock(&can_rcvlists_lock
);
490 d
= find_dev_rcv_lists(dev
);
492 printk(KERN_ERR
"BUG: receive list not found for "
493 "dev %s, id %03X, mask %03X\n",
494 DNAME(dev
), can_id
, mask
);
498 rl
= find_rcv_list(&can_id
, &mask
, d
);
501 * Search the receiver list for the item to delete. This should
502 * exist, since no receiver may be unregistered that hasn't
503 * been registered before.
506 hlist_for_each_entry_rcu(r
, next
, rl
, list
) {
507 if (r
->can_id
== can_id
&& r
->mask
== mask
&&
508 r
->func
== func
&& r
->data
== data
)
513 * Check for bugs in CAN protocol implementations:
514 * If no matching list item was found, the list cursor variable next
515 * will be NULL, while r will point to the last item of the list.
519 printk(KERN_ERR
"BUG: receive list entry not found for "
520 "dev %s, id %03X, mask %03X\n",
521 DNAME(dev
), can_id
, mask
);
526 hlist_del_rcu(&r
->list
);
529 if (can_pstats
.rcv_entries
> 0)
530 can_pstats
.rcv_entries
--;
532 /* remove device structure requested by NETDEV_UNREGISTER */
533 if (d
->remove_on_zero_entries
&& !d
->entries
) {
539 spin_unlock(&can_rcvlists_lock
);
541 /* schedule the receiver item for deletion */
543 call_rcu(&r
->rcu
, can_rx_delete_receiver
);
545 EXPORT_SYMBOL(can_rx_unregister
);
547 static inline void deliver(struct sk_buff
*skb
, struct receiver
*r
)
549 r
->func(skb
, r
->data
);
553 static int can_rcv_filter(struct dev_rcv_lists
*d
, struct sk_buff
*skb
)
556 struct hlist_node
*n
;
558 struct can_frame
*cf
= (struct can_frame
*)skb
->data
;
559 canid_t can_id
= cf
->can_id
;
564 if (can_id
& CAN_ERR_FLAG
) {
565 /* check for error frame entries only */
566 hlist_for_each_entry_rcu(r
, n
, &d
->rx
[RX_ERR
], list
) {
567 if (can_id
& r
->mask
) {
575 /* check for unfiltered entries */
576 hlist_for_each_entry_rcu(r
, n
, &d
->rx
[RX_ALL
], list
) {
581 /* check for can_id/mask entries */
582 hlist_for_each_entry_rcu(r
, n
, &d
->rx
[RX_FIL
], list
) {
583 if ((can_id
& r
->mask
) == r
->can_id
) {
589 /* check for inverted can_id/mask entries */
590 hlist_for_each_entry_rcu(r
, n
, &d
->rx
[RX_INV
], list
) {
591 if ((can_id
& r
->mask
) != r
->can_id
) {
597 /* check filterlists for single non-RTR can_ids */
598 if (can_id
& CAN_RTR_FLAG
)
601 if (can_id
& CAN_EFF_FLAG
) {
602 hlist_for_each_entry_rcu(r
, n
, &d
->rx
[RX_EFF
], list
) {
603 if (r
->can_id
== can_id
) {
609 can_id
&= CAN_SFF_MASK
;
610 hlist_for_each_entry_rcu(r
, n
, &d
->rx_sff
[can_id
], list
) {
619 static int can_rcv(struct sk_buff
*skb
, struct net_device
*dev
,
620 struct packet_type
*pt
, struct net_device
*orig_dev
)
622 struct dev_rcv_lists
*d
;
623 struct can_frame
*cf
= (struct can_frame
*)skb
->data
;
626 if (!net_eq(dev_net(dev
), &init_net
))
629 if (WARN_ONCE(dev
->type
!= ARPHRD_CAN
||
630 skb
->len
!= sizeof(struct can_frame
) ||
632 "PF_CAN: dropped non conform skbuf: "
633 "dev type %d, len %d, can_dlc %d\n",
634 dev
->type
, skb
->len
, cf
->can_dlc
))
637 /* update statistics */
638 can_stats
.rx_frames
++;
639 can_stats
.rx_frames_delta
++;
643 /* deliver the packet to sockets listening on all devices */
644 matches
= can_rcv_filter(&can_rx_alldev_list
, skb
);
646 /* find receive list for this device */
647 d
= find_dev_rcv_lists(dev
);
649 matches
+= can_rcv_filter(d
, skb
);
653 /* consume the skbuff allocated by the netdevice driver */
658 can_stats
.matches_delta
++;
661 return NET_RX_SUCCESS
;
669 * af_can protocol functions
673 * can_proto_register - register CAN transport protocol
674 * @cp: pointer to CAN protocol structure
678 * -EINVAL invalid (out of range) protocol number
679 * -EBUSY protocol already in use
680 * -ENOBUF if proto_register() fails
682 int can_proto_register(struct can_proto
*cp
)
684 int proto
= cp
->protocol
;
687 if (proto
< 0 || proto
>= CAN_NPROTO
) {
688 printk(KERN_ERR
"can: protocol number %d out of range\n",
693 err
= proto_register(cp
->prot
, 0);
697 spin_lock(&proto_tab_lock
);
698 if (proto_tab
[proto
]) {
699 printk(KERN_ERR
"can: protocol %d already registered\n",
703 proto_tab
[proto
] = cp
;
705 spin_unlock(&proto_tab_lock
);
708 proto_unregister(cp
->prot
);
712 EXPORT_SYMBOL(can_proto_register
);
715 * can_proto_unregister - unregister CAN transport protocol
716 * @cp: pointer to CAN protocol structure
718 void can_proto_unregister(struct can_proto
*cp
)
720 int proto
= cp
->protocol
;
722 spin_lock(&proto_tab_lock
);
723 if (!proto_tab
[proto
]) {
724 printk(KERN_ERR
"BUG: can: protocol %d is not registered\n",
727 proto_tab
[proto
] = NULL
;
728 spin_unlock(&proto_tab_lock
);
730 proto_unregister(cp
->prot
);
732 EXPORT_SYMBOL(can_proto_unregister
);
735 * af_can notifier to create/remove CAN netdevice specific structs
737 static int can_notifier(struct notifier_block
*nb
, unsigned long msg
,
740 struct net_device
*dev
= (struct net_device
*)data
;
741 struct dev_rcv_lists
*d
;
743 if (!net_eq(dev_net(dev
), &init_net
))
746 if (dev
->type
!= ARPHRD_CAN
)
751 case NETDEV_REGISTER
:
753 /* create new dev_rcv_lists for this device */
754 d
= kzalloc(sizeof(*d
), GFP_KERNEL
);
757 "can: allocation of receive list failed\n");
760 BUG_ON(dev
->ml_priv
);
765 case NETDEV_UNREGISTER
:
766 spin_lock(&can_rcvlists_lock
);
771 d
->remove_on_zero_entries
= 1;
777 printk(KERN_ERR
"can: notifier: receive list not "
778 "found for dev %s\n", dev
->name
);
780 spin_unlock(&can_rcvlists_lock
);
789 * af_can module init/exit functions
792 static struct packet_type can_packet __read_mostly
= {
793 .type
= cpu_to_be16(ETH_P_CAN
),
798 static const struct net_proto_family can_family_ops
= {
800 .create
= can_create
,
801 .owner
= THIS_MODULE
,
804 /* notifier block for netdevice event */
805 static struct notifier_block can_netdev_notifier __read_mostly
= {
806 .notifier_call
= can_notifier
,
809 static __init
int can_init(void)
813 memset(&can_rx_alldev_list
, 0, sizeof(can_rx_alldev_list
));
815 rcv_cache
= kmem_cache_create("can_receiver", sizeof(struct receiver
),
821 /* the statistics are updated every second (timer triggered) */
822 setup_timer(&can_stattimer
, can_stat_update
, 0);
823 mod_timer(&can_stattimer
, round_jiffies(jiffies
+ HZ
));
825 can_stattimer
.function
= NULL
;
829 /* protocol register */
830 sock_register(&can_family_ops
);
831 register_netdevice_notifier(&can_netdev_notifier
);
832 dev_add_pack(&can_packet
);
837 static __exit
void can_exit(void)
839 struct net_device
*dev
;
842 del_timer(&can_stattimer
);
846 /* protocol unregister */
847 dev_remove_pack(&can_packet
);
848 unregister_netdevice_notifier(&can_netdev_notifier
);
849 sock_unregister(PF_CAN
);
851 /* remove created dev_rcv_lists from still registered CAN devices */
853 for_each_netdev_rcu(&init_net
, dev
) {
854 if (dev
->type
== ARPHRD_CAN
&& dev
->ml_priv
){
856 struct dev_rcv_lists
*d
= dev
->ml_priv
;
865 rcu_barrier(); /* Wait for completion of call_rcu()'s */
867 kmem_cache_destroy(rcv_cache
);
870 module_init(can_init
);
871 module_exit(can_exit
);