Root/net/can/af_can.c

1/*
2 * af_can.c - Protocol family CAN core module
3 * (used by different CAN protocol modules)
4 *
5 * Copyright (c) 2002-2007 Volkswagen Group Electronic Research
6 * All rights reserved.
7 *
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.
19 *
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.
24 *
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.
27 *
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.
40 *
41 * Send feedback to <socketcan-users@lists.berlios.de>
42 *
43 */
44
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>
62#include <net/sock.h>
63
64#include "af_can.h"
65
66static __initdata const char banner[] = KERN_INFO
67    "can: controller area network core (" CAN_VERSION_STRING ")\n";
68
69MODULE_DESCRIPTION("Controller Area Network PF_CAN core");
70MODULE_LICENSE("Dual BSD/GPL");
71MODULE_AUTHOR("Urs Thuermann <urs.thuermann@volkswagen.de>, "
72          "Oliver Hartkopp <oliver.hartkopp@volkswagen.de>");
73
74MODULE_ALIAS_NETPROTO(PF_CAN);
75
76static int stats_timer __read_mostly = 1;
77module_param(stats_timer, int, S_IRUGO);
78MODULE_PARM_DESC(stats_timer, "enable timer for statistics (default:on)");
79
80/* receive filters subscribed for 'all' CAN devices */
81struct dev_rcv_lists can_rx_alldev_list;
82static DEFINE_SPINLOCK(can_rcvlists_lock);
83
84static struct kmem_cache *rcv_cache __read_mostly;
85
86/* table of registered CAN protocols */
87static struct can_proto *proto_tab[CAN_NPROTO] __read_mostly;
88static DEFINE_SPINLOCK(proto_tab_lock);
89
90struct timer_list can_stattimer; /* timer for statistics update */
91struct s_stats can_stats; /* packet statistics */
92struct s_pstats can_pstats; /* receive list statistics */
93
94/*
95 * af_can socket functions
96 */
97
98static int can_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
99{
100    struct sock *sk = sock->sk;
101
102    switch (cmd) {
103
104    case SIOCGSTAMP:
105        return sock_get_timestamp(sk, (struct timeval __user *)arg);
106
107    default:
108        return -ENOIOCTLCMD;
109    }
110}
111
112static void can_sock_destruct(struct sock *sk)
113{
114    skb_queue_purge(&sk->sk_receive_queue);
115}
116
117static int can_create(struct net *net, struct socket *sock, int protocol,
118              int kern)
119{
120    struct sock *sk;
121    struct can_proto *cp;
122    int err = 0;
123
124    sock->state = SS_UNCONNECTED;
125
126    if (protocol < 0 || protocol >= CAN_NPROTO)
127        return -EINVAL;
128
129    if (!net_eq(net, &init_net))
130        return -EAFNOSUPPORT;
131
132#ifdef CONFIG_MODULES
133    /* try to load protocol module kernel is modular */
134    if (!proto_tab[protocol]) {
135        err = request_module("can-proto-%d", protocol);
136
137        /*
138         * In case of error we only print a message but don't
139         * return the error code immediately. Below we will
140         * return -EPROTONOSUPPORT
141         */
142        if (err && printk_ratelimit())
143            printk(KERN_ERR "can: request_module "
144                   "(can-proto-%d) failed.\n", protocol);
145    }
146#endif
147
148    spin_lock(&proto_tab_lock);
149    cp = proto_tab[protocol];
150    if (cp && !try_module_get(cp->prot->owner))
151        cp = NULL;
152    spin_unlock(&proto_tab_lock);
153
154    /* check for available protocol and correct usage */
155
156    if (!cp)
157        return -EPROTONOSUPPORT;
158
159    if (cp->type != sock->type) {
160        err = -EPROTONOSUPPORT;
161        goto errout;
162    }
163
164    sock->ops = cp->ops;
165
166    sk = sk_alloc(net, PF_CAN, GFP_KERNEL, cp->prot);
167    if (!sk) {
168        err = -ENOMEM;
169        goto errout;
170    }
171
172    sock_init_data(sock, sk);
173    sk->sk_destruct = can_sock_destruct;
174
175    if (sk->sk_prot->init)
176        err = sk->sk_prot->init(sk);
177
178    if (err) {
179        /* release sk on errors */
180        sock_orphan(sk);
181        sock_put(sk);
182    }
183
184 errout:
185    module_put(cp->prot->owner);
186    return err;
187}
188
189/*
190 * af_can tx path
191 */
192
193/**
194 * can_send - transmit a CAN frame (optional with local loopback)
195 * @skb: pointer to socket buffer with CAN frame in data section
196 * @loop: loopback for listeners on local CAN sockets (recommended default!)
197 *
198 * Due to the loopback this routine must not be called from hardirq context.
199 *
200 * Return:
201 * 0 on success
202 * -ENETDOWN when the selected interface is down
203 * -ENOBUFS on full driver queue (see net_xmit_errno())
204 * -ENOMEM when local loopback failed at calling skb_clone()
205 * -EPERM when trying to send on a non-CAN interface
206 * -EINVAL when the skb->data does not contain a valid CAN frame
207 */
208int can_send(struct sk_buff *skb, int loop)
209{
210    struct sk_buff *newskb = NULL;
211    struct can_frame *cf = (struct can_frame *)skb->data;
212    int err;
213
214    if (skb->len != sizeof(struct can_frame) || cf->can_dlc > 8) {
215        kfree_skb(skb);
216        return -EINVAL;
217    }
218
219    if (skb->dev->type != ARPHRD_CAN) {
220        kfree_skb(skb);
221        return -EPERM;
222    }
223
224    if (!(skb->dev->flags & IFF_UP)) {
225        kfree_skb(skb);
226        return -ENETDOWN;
227    }
228
229    skb->protocol = htons(ETH_P_CAN);
230    skb_reset_network_header(skb);
231    skb_reset_transport_header(skb);
232
233    if (loop) {
234        /* local loopback of sent CAN frames */
235
236        /* indication for the CAN driver: do loopback */
237        skb->pkt_type = PACKET_LOOPBACK;
238
239        /*
240         * The reference to the originating sock may be required
241         * by the receiving socket to check whether the frame is
242         * its own. Example: can_raw sockopt CAN_RAW_RECV_OWN_MSGS
243         * Therefore we have to ensure that skb->sk remains the
244         * reference to the originating sock by restoring skb->sk
245         * after each skb_clone() or skb_orphan() usage.
246         */
247
248        if (!(skb->dev->flags & IFF_ECHO)) {
249            /*
250             * If the interface is not capable to do loopback
251             * itself, we do it here.
252             */
253            newskb = skb_clone(skb, GFP_ATOMIC);
254            if (!newskb) {
255                kfree_skb(skb);
256                return -ENOMEM;
257            }
258
259            newskb->sk = skb->sk;
260            newskb->ip_summed = CHECKSUM_UNNECESSARY;
261            newskb->pkt_type = PACKET_BROADCAST;
262        }
263    } else {
264        /* indication for the CAN driver: no loopback required */
265        skb->pkt_type = PACKET_HOST;
266    }
267
268    /* send to netdevice */
269    err = dev_queue_xmit(skb);
270    if (err > 0)
271        err = net_xmit_errno(err);
272
273    if (err) {
274        kfree_skb(newskb);
275        return err;
276    }
277
278    if (newskb)
279        netif_rx_ni(newskb);
280
281    /* update statistics */
282    can_stats.tx_frames++;
283    can_stats.tx_frames_delta++;
284
285    return 0;
286}
287EXPORT_SYMBOL(can_send);
288
289/*
290 * af_can rx path
291 */
292
293static struct dev_rcv_lists *find_dev_rcv_lists(struct net_device *dev)
294{
295    if (!dev)
296        return &can_rx_alldev_list;
297    else
298        return (struct dev_rcv_lists *)dev->ml_priv;
299}
300
301/**
302 * find_rcv_list - determine optimal filterlist inside device filter struct
303 * @can_id: pointer to CAN identifier of a given can_filter
304 * @mask: pointer to CAN mask of a given can_filter
305 * @d: pointer to the device filter struct
306 *
307 * Description:
308 * Returns the optimal filterlist to reduce the filter handling in the
309 * receive path. This function is called by service functions that need
310 * to register or unregister a can_filter in the filter lists.
311 *
312 * A filter matches in general, when
313 *
314 * <received_can_id> & mask == can_id & mask
315 *
316 * so every bit set in the mask (even CAN_EFF_FLAG, CAN_RTR_FLAG) describe
317 * relevant bits for the filter.
318 *
319 * The filter can be inverted (CAN_INV_FILTER bit set in can_id) or it can
320 * filter for error frames (CAN_ERR_FLAG bit set in mask). For error frames
321 * there is a special filterlist and a special rx path filter handling.
322 *
323 * Return:
324 * Pointer to optimal filterlist for the given can_id/mask pair.
325 * Constistency checked mask.
326 * Reduced can_id to have a preprocessed filter compare value.
327 */
328static struct hlist_head *find_rcv_list(canid_t *can_id, canid_t *mask,
329                    struct dev_rcv_lists *d)
330{
331    canid_t inv = *can_id & CAN_INV_FILTER; /* save flag before masking */
332
333    /* filter for error frames in extra filterlist */
334    if (*mask & CAN_ERR_FLAG) {
335        /* clear CAN_ERR_FLAG in filter entry */
336        *mask &= CAN_ERR_MASK;
337        return &d->rx[RX_ERR];
338    }
339
340    /* with cleared CAN_ERR_FLAG we have a simple mask/value filterpair */
341
342#define CAN_EFF_RTR_FLAGS (CAN_EFF_FLAG | CAN_RTR_FLAG)
343
344    /* ensure valid values in can_mask for 'SFF only' frame filtering */
345    if ((*mask & CAN_EFF_FLAG) && !(*can_id & CAN_EFF_FLAG))
346        *mask &= (CAN_SFF_MASK | CAN_EFF_RTR_FLAGS);
347
348    /* reduce condition testing at receive time */
349    *can_id &= *mask;
350
351    /* inverse can_id/can_mask filter */
352    if (inv)
353        return &d->rx[RX_INV];
354
355    /* mask == 0 => no condition testing at receive time */
356    if (!(*mask))
357        return &d->rx[RX_ALL];
358
359    /* extra filterlists for the subscription of a single non-RTR can_id */
360    if (((*mask & CAN_EFF_RTR_FLAGS) == CAN_EFF_RTR_FLAGS) &&
361        !(*can_id & CAN_RTR_FLAG)) {
362
363        if (*can_id & CAN_EFF_FLAG) {
364            if (*mask == (CAN_EFF_MASK | CAN_EFF_RTR_FLAGS)) {
365                /* RFC: a future use-case for hash-tables? */
366                return &d->rx[RX_EFF];
367            }
368        } else {
369            if (*mask == (CAN_SFF_MASK | CAN_EFF_RTR_FLAGS))
370                return &d->rx_sff[*can_id];
371        }
372    }
373
374    /* default: filter via can_id/can_mask */
375    return &d->rx[RX_FIL];
376}
377
378/**
379 * can_rx_register - subscribe CAN frames from a specific interface
380 * @dev: pointer to netdevice (NULL => subcribe from 'all' CAN devices list)
381 * @can_id: CAN identifier (see description)
382 * @mask: CAN mask (see description)
383 * @func: callback function on filter match
384 * @data: returned parameter for callback function
385 * @ident: string for calling module indentification
386 *
387 * Description:
388 * Invokes the callback function with the received sk_buff and the given
389 * parameter 'data' on a matching receive filter. A filter matches, when
390 *
391 * <received_can_id> & mask == can_id & mask
392 *
393 * The filter can be inverted (CAN_INV_FILTER bit set in can_id) or it can
394 * filter for error frames (CAN_ERR_FLAG bit set in mask).
395 *
396 * The provided pointer to the sk_buff is guaranteed to be valid as long as
397 * the callback function is running. The callback function must *not* free
398 * the given sk_buff while processing it's task. When the given sk_buff is
399 * needed after the end of the callback function it must be cloned inside
400 * the callback function with skb_clone().
401 *
402 * Return:
403 * 0 on success
404 * -ENOMEM on missing cache mem to create subscription entry
405 * -ENODEV unknown device
406 */
407int can_rx_register(struct net_device *dev, canid_t can_id, canid_t mask,
408            void (*func)(struct sk_buff *, void *), void *data,
409            char *ident)
410{
411    struct receiver *r;
412    struct hlist_head *rl;
413    struct dev_rcv_lists *d;
414    int err = 0;
415
416    /* insert new receiver (dev,canid,mask) -> (func,data) */
417
418    if (dev && dev->type != ARPHRD_CAN)
419        return -ENODEV;
420
421    r = kmem_cache_alloc(rcv_cache, GFP_KERNEL);
422    if (!r)
423        return -ENOMEM;
424
425    spin_lock(&can_rcvlists_lock);
426
427    d = find_dev_rcv_lists(dev);
428    if (d) {
429        rl = find_rcv_list(&can_id, &mask, d);
430
431        r->can_id = can_id;
432        r->mask = mask;
433        r->matches = 0;
434        r->func = func;
435        r->data = data;
436        r->ident = ident;
437
438        hlist_add_head_rcu(&r->list, rl);
439        d->entries++;
440
441        can_pstats.rcv_entries++;
442        if (can_pstats.rcv_entries_max < can_pstats.rcv_entries)
443            can_pstats.rcv_entries_max = can_pstats.rcv_entries;
444    } else {
445        kmem_cache_free(rcv_cache, r);
446        err = -ENODEV;
447    }
448
449    spin_unlock(&can_rcvlists_lock);
450
451    return err;
452}
453EXPORT_SYMBOL(can_rx_register);
454
455/*
456 * can_rx_delete_receiver - rcu callback for single receiver entry removal
457 */
458static void can_rx_delete_receiver(struct rcu_head *rp)
459{
460    struct receiver *r = container_of(rp, struct receiver, rcu);
461
462    kmem_cache_free(rcv_cache, r);
463}
464
465/**
466 * can_rx_unregister - unsubscribe CAN frames from a specific interface
467 * @dev: pointer to netdevice (NULL => unsubcribe from 'all' CAN devices list)
468 * @can_id: CAN identifier
469 * @mask: CAN mask
470 * @func: callback function on filter match
471 * @data: returned parameter for callback function
472 *
473 * Description:
474 * Removes subscription entry depending on given (subscription) values.
475 */
476void can_rx_unregister(struct net_device *dev, canid_t can_id, canid_t mask,
477               void (*func)(struct sk_buff *, void *), void *data)
478{
479    struct receiver *r = NULL;
480    struct hlist_head *rl;
481    struct hlist_node *next;
482    struct dev_rcv_lists *d;
483
484    if (dev && dev->type != ARPHRD_CAN)
485        return;
486
487    spin_lock(&can_rcvlists_lock);
488
489    d = find_dev_rcv_lists(dev);
490    if (!d) {
491        printk(KERN_ERR "BUG: receive list not found for "
492               "dev %s, id %03X, mask %03X\n",
493               DNAME(dev), can_id, mask);
494        goto out;
495    }
496
497    rl = find_rcv_list(&can_id, &mask, d);
498
499    /*
500     * Search the receiver list for the item to delete. This should
501     * exist, since no receiver may be unregistered that hasn't
502     * been registered before.
503     */
504
505    hlist_for_each_entry_rcu(r, next, rl, list) {
506        if (r->can_id == can_id && r->mask == mask &&
507            r->func == func && r->data == data)
508            break;
509    }
510
511    /*
512     * Check for bugs in CAN protocol implementations:
513     * If no matching list item was found, the list cursor variable next
514     * will be NULL, while r will point to the last item of the list.
515     */
516
517    if (!next) {
518        printk(KERN_ERR "BUG: receive list entry not found for "
519               "dev %s, id %03X, mask %03X\n",
520               DNAME(dev), can_id, mask);
521        r = NULL;
522        goto out;
523    }
524
525    hlist_del_rcu(&r->list);
526    d->entries--;
527
528    if (can_pstats.rcv_entries > 0)
529        can_pstats.rcv_entries--;
530
531    /* remove device structure requested by NETDEV_UNREGISTER */
532    if (d->remove_on_zero_entries && !d->entries) {
533        kfree(d);
534        dev->ml_priv = NULL;
535    }
536
537 out:
538    spin_unlock(&can_rcvlists_lock);
539
540    /* schedule the receiver item for deletion */
541    if (r)
542        call_rcu(&r->rcu, can_rx_delete_receiver);
543}
544EXPORT_SYMBOL(can_rx_unregister);
545
546static inline void deliver(struct sk_buff *skb, struct receiver *r)
547{
548    r->func(skb, r->data);
549    r->matches++;
550}
551
552static int can_rcv_filter(struct dev_rcv_lists *d, struct sk_buff *skb)
553{
554    struct receiver *r;
555    struct hlist_node *n;
556    int matches = 0;
557    struct can_frame *cf = (struct can_frame *)skb->data;
558    canid_t can_id = cf->can_id;
559
560    if (d->entries == 0)
561        return 0;
562
563    if (can_id & CAN_ERR_FLAG) {
564        /* check for error frame entries only */
565        hlist_for_each_entry_rcu(r, n, &d->rx[RX_ERR], list) {
566            if (can_id & r->mask) {
567                deliver(skb, r);
568                matches++;
569            }
570        }
571        return matches;
572    }
573
574    /* check for unfiltered entries */
575    hlist_for_each_entry_rcu(r, n, &d->rx[RX_ALL], list) {
576        deliver(skb, r);
577        matches++;
578    }
579
580    /* check for can_id/mask entries */
581    hlist_for_each_entry_rcu(r, n, &d->rx[RX_FIL], list) {
582        if ((can_id & r->mask) == r->can_id) {
583            deliver(skb, r);
584            matches++;
585        }
586    }
587
588    /* check for inverted can_id/mask entries */
589    hlist_for_each_entry_rcu(r, n, &d->rx[RX_INV], list) {
590        if ((can_id & r->mask) != r->can_id) {
591            deliver(skb, r);
592            matches++;
593        }
594    }
595
596    /* check filterlists for single non-RTR can_ids */
597    if (can_id & CAN_RTR_FLAG)
598        return matches;
599
600    if (can_id & CAN_EFF_FLAG) {
601        hlist_for_each_entry_rcu(r, n, &d->rx[RX_EFF], list) {
602            if (r->can_id == can_id) {
603                deliver(skb, r);
604                matches++;
605            }
606        }
607    } else {
608        can_id &= CAN_SFF_MASK;
609        hlist_for_each_entry_rcu(r, n, &d->rx_sff[can_id], list) {
610            deliver(skb, r);
611            matches++;
612        }
613    }
614
615    return matches;
616}
617
618static int can_rcv(struct sk_buff *skb, struct net_device *dev,
619           struct packet_type *pt, struct net_device *orig_dev)
620{
621    struct dev_rcv_lists *d;
622    struct can_frame *cf = (struct can_frame *)skb->data;
623    int matches;
624
625    if (!net_eq(dev_net(dev), &init_net))
626        goto drop;
627
628    if (WARN_ONCE(dev->type != ARPHRD_CAN ||
629              skb->len != sizeof(struct can_frame) ||
630              cf->can_dlc > 8,
631              "PF_CAN: dropped non conform skbuf: "
632              "dev type %d, len %d, can_dlc %d\n",
633              dev->type, skb->len, cf->can_dlc))
634        goto drop;
635
636    /* update statistics */
637    can_stats.rx_frames++;
638    can_stats.rx_frames_delta++;
639
640    rcu_read_lock();
641
642    /* deliver the packet to sockets listening on all devices */
643    matches = can_rcv_filter(&can_rx_alldev_list, skb);
644
645    /* find receive list for this device */
646    d = find_dev_rcv_lists(dev);
647    if (d)
648        matches += can_rcv_filter(d, skb);
649
650    rcu_read_unlock();
651
652    /* consume the skbuff allocated by the netdevice driver */
653    consume_skb(skb);
654
655    if (matches > 0) {
656        can_stats.matches++;
657        can_stats.matches_delta++;
658    }
659
660    return NET_RX_SUCCESS;
661
662drop:
663    kfree_skb(skb);
664    return NET_RX_DROP;
665}
666
667/*
668 * af_can protocol functions
669 */
670
671/**
672 * can_proto_register - register CAN transport protocol
673 * @cp: pointer to CAN protocol structure
674 *
675 * Return:
676 * 0 on success
677 * -EINVAL invalid (out of range) protocol number
678 * -EBUSY protocol already in use
679 * -ENOBUF if proto_register() fails
680 */
681int can_proto_register(struct can_proto *cp)
682{
683    int proto = cp->protocol;
684    int err = 0;
685
686    if (proto < 0 || proto >= CAN_NPROTO) {
687        printk(KERN_ERR "can: protocol number %d out of range\n",
688               proto);
689        return -EINVAL;
690    }
691
692    err = proto_register(cp->prot, 0);
693    if (err < 0)
694        return err;
695
696    spin_lock(&proto_tab_lock);
697    if (proto_tab[proto]) {
698        printk(KERN_ERR "can: protocol %d already registered\n",
699               proto);
700        err = -EBUSY;
701    } else {
702        proto_tab[proto] = cp;
703
704        /* use generic ioctl function if not defined by module */
705        if (!cp->ops->ioctl)
706            cp->ops->ioctl = can_ioctl;
707    }
708    spin_unlock(&proto_tab_lock);
709
710    if (err < 0)
711        proto_unregister(cp->prot);
712
713    return err;
714}
715EXPORT_SYMBOL(can_proto_register);
716
717/**
718 * can_proto_unregister - unregister CAN transport protocol
719 * @cp: pointer to CAN protocol structure
720 */
721void can_proto_unregister(struct can_proto *cp)
722{
723    int proto = cp->protocol;
724
725    spin_lock(&proto_tab_lock);
726    if (!proto_tab[proto]) {
727        printk(KERN_ERR "BUG: can: protocol %d is not registered\n",
728               proto);
729    }
730    proto_tab[proto] = NULL;
731    spin_unlock(&proto_tab_lock);
732
733    proto_unregister(cp->prot);
734}
735EXPORT_SYMBOL(can_proto_unregister);
736
737/*
738 * af_can notifier to create/remove CAN netdevice specific structs
739 */
740static int can_notifier(struct notifier_block *nb, unsigned long msg,
741            void *data)
742{
743    struct net_device *dev = (struct net_device *)data;
744    struct dev_rcv_lists *d;
745
746    if (!net_eq(dev_net(dev), &init_net))
747        return NOTIFY_DONE;
748
749    if (dev->type != ARPHRD_CAN)
750        return NOTIFY_DONE;
751
752    switch (msg) {
753
754    case NETDEV_REGISTER:
755
756        /* create new dev_rcv_lists for this device */
757        d = kzalloc(sizeof(*d), GFP_KERNEL);
758        if (!d) {
759            printk(KERN_ERR
760                   "can: allocation of receive list failed\n");
761            return NOTIFY_DONE;
762        }
763        BUG_ON(dev->ml_priv);
764        dev->ml_priv = d;
765
766        break;
767
768    case NETDEV_UNREGISTER:
769        spin_lock(&can_rcvlists_lock);
770
771        d = dev->ml_priv;
772        if (d) {
773            if (d->entries)
774                d->remove_on_zero_entries = 1;
775            else {
776                kfree(d);
777                dev->ml_priv = NULL;
778            }
779        } else
780            printk(KERN_ERR "can: notifier: receive list not "
781                   "found for dev %s\n", dev->name);
782
783        spin_unlock(&can_rcvlists_lock);
784
785        break;
786    }
787
788    return NOTIFY_DONE;
789}
790
791/*
792 * af_can module init/exit functions
793 */
794
795static struct packet_type can_packet __read_mostly = {
796    .type = cpu_to_be16(ETH_P_CAN),
797    .dev = NULL,
798    .func = can_rcv,
799};
800
801static const struct net_proto_family can_family_ops = {
802    .family = PF_CAN,
803    .create = can_create,
804    .owner = THIS_MODULE,
805};
806
807/* notifier block for netdevice event */
808static struct notifier_block can_netdev_notifier __read_mostly = {
809    .notifier_call = can_notifier,
810};
811
812static __init int can_init(void)
813{
814    printk(banner);
815
816    memset(&can_rx_alldev_list, 0, sizeof(can_rx_alldev_list));
817
818    rcv_cache = kmem_cache_create("can_receiver", sizeof(struct receiver),
819                      0, 0, NULL);
820    if (!rcv_cache)
821        return -ENOMEM;
822
823    if (stats_timer) {
824        /* the statistics are updated every second (timer triggered) */
825        setup_timer(&can_stattimer, can_stat_update, 0);
826        mod_timer(&can_stattimer, round_jiffies(jiffies + HZ));
827    } else
828        can_stattimer.function = NULL;
829
830    can_init_proc();
831
832    /* protocol register */
833    sock_register(&can_family_ops);
834    register_netdevice_notifier(&can_netdev_notifier);
835    dev_add_pack(&can_packet);
836
837    return 0;
838}
839
840static __exit void can_exit(void)
841{
842    struct net_device *dev;
843
844    if (stats_timer)
845        del_timer(&can_stattimer);
846
847    can_remove_proc();
848
849    /* protocol unregister */
850    dev_remove_pack(&can_packet);
851    unregister_netdevice_notifier(&can_netdev_notifier);
852    sock_unregister(PF_CAN);
853
854    /* remove created dev_rcv_lists from still registered CAN devices */
855    rcu_read_lock();
856    for_each_netdev_rcu(&init_net, dev) {
857        if (dev->type == ARPHRD_CAN && dev->ml_priv){
858
859            struct dev_rcv_lists *d = dev->ml_priv;
860
861            BUG_ON(d->entries);
862            kfree(d);
863            dev->ml_priv = NULL;
864        }
865    }
866    rcu_read_unlock();
867
868    rcu_barrier(); /* Wait for completion of call_rcu()'s */
869
870    kmem_cache_destroy(rcv_cache);
871}
872
873module_init(can_init);
874module_exit(can_exit);
875

Archive Download this file

Branches:
ben-wpan
ben-wpan-stefan
javiroman/ks7010
jz-2.6.34
jz-2.6.34-rc5
jz-2.6.34-rc6
jz-2.6.34-rc7
jz-2.6.35
jz-2.6.36
jz-2.6.37
jz-2.6.38
jz-2.6.39
jz-3.0
jz-3.1
jz-3.11
jz-3.12
jz-3.13
jz-3.15
jz-3.16
jz-3.18-dt
jz-3.2
jz-3.3
jz-3.4
jz-3.5
jz-3.6
jz-3.6-rc2-pwm
jz-3.9
jz-3.9-clk
jz-3.9-rc8
jz47xx
jz47xx-2.6.38
master

Tags:
od-2011-09-04
od-2011-09-18
v2.6.34-rc5
v2.6.34-rc6
v2.6.34-rc7
v3.9



interactive