1// SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause)
  2/* af_can.c - Protocol family CAN core module
  3 *            (used by different CAN protocol modules)
  4 *
  5 * Copyright (c) 2002-2017 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 */
 42
 43#include <linux/module.h>
 44#include <linux/stddef.h>
 45#include <linux/init.h>
 46#include <linux/kmod.h>
 47#include <linux/slab.h>
 48#include <linux/list.h>
 49#include <linux/spinlock.h>
 50#include <linux/rcupdate.h>
 51#include <linux/uaccess.h>
 52#include <linux/net.h>
 53#include <linux/netdevice.h>
 54#include <linux/socket.h>
 55#include <linux/if_ether.h>
 56#include <linux/if_arp.h>
 57#include <linux/skbuff.h>
 58#include <linux/can.h>
 59#include <linux/can/core.h>
 60#include <linux/can/skb.h>
 61#include <linux/can/can-ml.h>
 62#include <linux/ratelimit.h>
 63#include <net/net_namespace.h>
 64#include <net/sock.h>
 65
 66#include "af_can.h"
 67
 68MODULE_DESCRIPTION("Controller Area Network PF_CAN core");
 69MODULE_LICENSE("Dual BSD/GPL");
 70MODULE_AUTHOR("Urs Thuermann <urs.thuermann@volkswagen.de>, "
 71	      "Oliver Hartkopp <oliver.hartkopp@volkswagen.de>");
 72
 73MODULE_ALIAS_NETPROTO(PF_CAN);
 74
 75static int stats_timer __read_mostly = 1;
 76module_param(stats_timer, int, 0444);
 77MODULE_PARM_DESC(stats_timer, "enable timer for statistics (default:on)");
 78
 79static struct kmem_cache *rcv_cache __read_mostly;
 80
 81/* table of registered CAN protocols */
 82static const struct can_proto __rcu *proto_tab[CAN_NPROTO] __read_mostly;
 83static DEFINE_MUTEX(proto_tab_lock);
 84
 85static atomic_t skbcounter = ATOMIC_INIT(0);
 86
 87/* af_can socket functions */
 88
 89void can_sock_destruct(struct sock *sk)
 90{
 91	skb_queue_purge(&sk->sk_receive_queue);
 92	skb_queue_purge(&sk->sk_error_queue);
 93}
 94EXPORT_SYMBOL(can_sock_destruct);
 95
 96static const struct can_proto *can_get_proto(int protocol)
 97{
 98	const struct can_proto *cp;
 99
100	rcu_read_lock();
101	cp = rcu_dereference(proto_tab[protocol]);
102	if (cp && !try_module_get(cp->prot->owner))
103		cp = NULL;
104	rcu_read_unlock();
105
106	return cp;
107}
108
109static inline void can_put_proto(const struct can_proto *cp)
110{
111	module_put(cp->prot->owner);
112}
113
114static int can_create(struct net *net, struct socket *sock, int protocol,
115		      int kern)
116{
117	struct sock *sk;
118	const struct can_proto *cp;
119	int err = 0;
120
121	sock->state = SS_UNCONNECTED;
122
123	if (protocol < 0 || protocol >= CAN_NPROTO)
124		return -EINVAL;
125
126	cp = can_get_proto(protocol);
127
128#ifdef CONFIG_MODULES
129	if (!cp) {
130		/* try to load protocol module if kernel is modular */
131
132		err = request_module("can-proto-%d", protocol);
133
134		/* In case of error we only print a message but don't
135		 * return the error code immediately.  Below we will
136		 * return -EPROTONOSUPPORT
137		 */
138		if (err)
139			pr_err_ratelimited("can: request_module (can-proto-%d) failed.\n",
140					   protocol);
141
142		cp = can_get_proto(protocol);
143	}
144#endif
145
146	/* check for available protocol and correct usage */
147
148	if (!cp)
149		return -EPROTONOSUPPORT;
150
151	if (cp->type != sock->type) {
152		err = -EPROTOTYPE;
153		goto errout;
154	}
155
156	sock->ops = cp->ops;
157
158	sk = sk_alloc(net, PF_CAN, GFP_KERNEL, cp->prot, kern);
159	if (!sk) {
160		err = -ENOMEM;
161		goto errout;
162	}
163
164	sock_init_data(sock, sk);
165	sk->sk_destruct = can_sock_destruct;
166
167	if (sk->sk_prot->init)
168		err = sk->sk_prot->init(sk);
169
170	if (err) {
171		/* release sk on errors */
172		sock_orphan(sk);
173		sock_put(sk);
174		sock->sk = NULL;
175	}
176
177 errout:
178	can_put_proto(cp);
179	return err;
180}
181
182/* af_can tx path */
183
184/**
185 * can_send - transmit a CAN frame (optional with local loopback)
186 * @skb: pointer to socket buffer with CAN frame in data section
187 * @loop: loopback for listeners on local CAN sockets (recommended default!)
188 *
189 * Due to the loopback this routine must not be called from hardirq context.
190 *
191 * Return:
192 *  0 on success
193 *  -ENETDOWN when the selected interface is down
194 *  -ENOBUFS on full driver queue (see net_xmit_errno())
195 *  -ENOMEM when local loopback failed at calling skb_clone()
196 *  -EPERM when trying to send on a non-CAN interface
197 *  -EMSGSIZE CAN frame size is bigger than CAN interface MTU
198 *  -EINVAL when the skb->data does not contain a valid CAN frame
199 */
200int can_send(struct sk_buff *skb, int loop)
201{
202	struct sk_buff *newskb = NULL;
 
203	struct can_pkg_stats *pkg_stats = dev_net(skb->dev)->can.pkg_stats;
204	int err = -EINVAL;
205
206	if (can_is_canxl_skb(skb)) {
207		skb->protocol = htons(ETH_P_CANXL);
208	} else if (can_is_can_skb(skb)) {
209		skb->protocol = htons(ETH_P_CAN);
210	} else if (can_is_canfd_skb(skb)) {
211		struct canfd_frame *cfd = (struct canfd_frame *)skb->data;
212
213		skb->protocol = htons(ETH_P_CANFD);
214
215		/* set CAN FD flag for CAN FD frames by default */
216		cfd->flags |= CANFD_FDF;
217	} else {
218		goto inval_skb;
219	}
220
221	/* Make sure the CAN frame can pass the selected CAN netdevice. */
222	if (unlikely(skb->len > skb->dev->mtu)) {
 
 
 
223		err = -EMSGSIZE;
224		goto inval_skb;
225	}
226
227	if (unlikely(skb->dev->type != ARPHRD_CAN)) {
228		err = -EPERM;
229		goto inval_skb;
230	}
231
232	if (unlikely(!(skb->dev->flags & IFF_UP))) {
233		err = -ENETDOWN;
234		goto inval_skb;
235	}
236
237	skb->ip_summed = CHECKSUM_UNNECESSARY;
238
239	skb_reset_mac_header(skb);
240	skb_reset_network_header(skb);
241	skb_reset_transport_header(skb);
242
243	if (loop) {
244		/* local loopback of sent CAN frames */
245
246		/* indication for the CAN driver: do loopback */
247		skb->pkt_type = PACKET_LOOPBACK;
248
249		/* The reference to the originating sock may be required
250		 * by the receiving socket to check whether the frame is
251		 * its own. Example: can_raw sockopt CAN_RAW_RECV_OWN_MSGS
252		 * Therefore we have to ensure that skb->sk remains the
253		 * reference to the originating sock by restoring skb->sk
254		 * after each skb_clone() or skb_orphan() usage.
255		 */
256
257		if (!(skb->dev->flags & IFF_ECHO)) {
258			/* If the interface is not capable to do loopback
259			 * itself, we do it here.
260			 */
261			newskb = skb_clone(skb, GFP_ATOMIC);
262			if (!newskb) {
263				kfree_skb(skb);
264				return -ENOMEM;
265			}
266
267			can_skb_set_owner(newskb, skb->sk);
268			newskb->ip_summed = CHECKSUM_UNNECESSARY;
269			newskb->pkt_type = PACKET_BROADCAST;
270		}
271	} else {
272		/* indication for the CAN driver: no loopback required */
273		skb->pkt_type = PACKET_HOST;
274	}
275
276	/* send to netdevice */
277	err = dev_queue_xmit(skb);
278	if (err > 0)
279		err = net_xmit_errno(err);
280
281	if (err) {
282		kfree_skb(newskb);
283		return err;
284	}
285
286	if (newskb)
287		netif_rx(newskb);
288
289	/* update statistics */
290	pkg_stats->tx_frames++;
291	pkg_stats->tx_frames_delta++;
292
293	return 0;
294
295inval_skb:
296	kfree_skb(skb);
297	return err;
298}
299EXPORT_SYMBOL(can_send);
300
301/* af_can rx path */
302
303static struct can_dev_rcv_lists *can_dev_rcv_lists_find(struct net *net,
304							struct net_device *dev)
305{
306	if (dev) {
307		struct can_ml_priv *can_ml = can_get_ml_priv(dev);
308		return &can_ml->dev_rcv_lists;
309	} else {
310		return net->can.rx_alldev_list;
311	}
312}
313
314/**
315 * effhash - hash function for 29 bit CAN identifier reduction
316 * @can_id: 29 bit CAN identifier
317 *
318 * Description:
319 *  To reduce the linear traversal in one linked list of _single_ EFF CAN
320 *  frame subscriptions the 29 bit identifier is mapped to 10 bits.
321 *  (see CAN_EFF_RCV_HASH_BITS definition)
322 *
323 * Return:
324 *  Hash value from 0x000 - 0x3FF ( enforced by CAN_EFF_RCV_HASH_BITS mask )
325 */
326static unsigned int effhash(canid_t can_id)
327{
328	unsigned int hash;
329
330	hash = can_id;
331	hash ^= can_id >> CAN_EFF_RCV_HASH_BITS;
332	hash ^= can_id >> (2 * CAN_EFF_RCV_HASH_BITS);
333
334	return hash & ((1 << CAN_EFF_RCV_HASH_BITS) - 1);
335}
336
337/**
338 * can_rcv_list_find - determine optimal filterlist inside device filter struct
339 * @can_id: pointer to CAN identifier of a given can_filter
340 * @mask: pointer to CAN mask of a given can_filter
341 * @dev_rcv_lists: pointer to the device filter struct
342 *
343 * Description:
344 *  Returns the optimal filterlist to reduce the filter handling in the
345 *  receive path. This function is called by service functions that need
346 *  to register or unregister a can_filter in the filter lists.
347 *
348 *  A filter matches in general, when
349 *
350 *          <received_can_id> & mask == can_id & mask
351 *
352 *  so every bit set in the mask (even CAN_EFF_FLAG, CAN_RTR_FLAG) describe
353 *  relevant bits for the filter.
354 *
355 *  The filter can be inverted (CAN_INV_FILTER bit set in can_id) or it can
356 *  filter for error messages (CAN_ERR_FLAG bit set in mask). For error msg
357 *  frames there is a special filterlist and a special rx path filter handling.
358 *
359 * Return:
360 *  Pointer to optimal filterlist for the given can_id/mask pair.
361 *  Consistency checked mask.
362 *  Reduced can_id to have a preprocessed filter compare value.
363 */
364static struct hlist_head *can_rcv_list_find(canid_t *can_id, canid_t *mask,
365					    struct can_dev_rcv_lists *dev_rcv_lists)
366{
367	canid_t inv = *can_id & CAN_INV_FILTER; /* save flag before masking */
368
369	/* filter for error message frames in extra filterlist */
370	if (*mask & CAN_ERR_FLAG) {
371		/* clear CAN_ERR_FLAG in filter entry */
372		*mask &= CAN_ERR_MASK;
373		return &dev_rcv_lists->rx[RX_ERR];
374	}
375
376	/* with cleared CAN_ERR_FLAG we have a simple mask/value filterpair */
377
378#define CAN_EFF_RTR_FLAGS (CAN_EFF_FLAG | CAN_RTR_FLAG)
379
380	/* ensure valid values in can_mask for 'SFF only' frame filtering */
381	if ((*mask & CAN_EFF_FLAG) && !(*can_id & CAN_EFF_FLAG))
382		*mask &= (CAN_SFF_MASK | CAN_EFF_RTR_FLAGS);
383
384	/* reduce condition testing at receive time */
385	*can_id &= *mask;
386
387	/* inverse can_id/can_mask filter */
388	if (inv)
389		return &dev_rcv_lists->rx[RX_INV];
390
391	/* mask == 0 => no condition testing at receive time */
392	if (!(*mask))
393		return &dev_rcv_lists->rx[RX_ALL];
394
395	/* extra filterlists for the subscription of a single non-RTR can_id */
396	if (((*mask & CAN_EFF_RTR_FLAGS) == CAN_EFF_RTR_FLAGS) &&
397	    !(*can_id & CAN_RTR_FLAG)) {
398		if (*can_id & CAN_EFF_FLAG) {
399			if (*mask == (CAN_EFF_MASK | CAN_EFF_RTR_FLAGS))
400				return &dev_rcv_lists->rx_eff[effhash(*can_id)];
401		} else {
402			if (*mask == (CAN_SFF_MASK | CAN_EFF_RTR_FLAGS))
403				return &dev_rcv_lists->rx_sff[*can_id];
404		}
405	}
406
407	/* default: filter via can_id/can_mask */
408	return &dev_rcv_lists->rx[RX_FIL];
409}
410
411/**
412 * can_rx_register - subscribe CAN frames from a specific interface
413 * @net: the applicable net namespace
414 * @dev: pointer to netdevice (NULL => subscribe from 'all' CAN devices list)
415 * @can_id: CAN identifier (see description)
416 * @mask: CAN mask (see description)
417 * @func: callback function on filter match
418 * @data: returned parameter for callback function
419 * @ident: string for calling module identification
420 * @sk: socket pointer (might be NULL)
421 *
422 * Description:
423 *  Invokes the callback function with the received sk_buff and the given
424 *  parameter 'data' on a matching receive filter. A filter matches, when
425 *
426 *          <received_can_id> & mask == can_id & mask
427 *
428 *  The filter can be inverted (CAN_INV_FILTER bit set in can_id) or it can
429 *  filter for error message frames (CAN_ERR_FLAG bit set in mask).
430 *
431 *  The provided pointer to the sk_buff is guaranteed to be valid as long as
432 *  the callback function is running. The callback function must *not* free
433 *  the given sk_buff while processing it's task. When the given sk_buff is
434 *  needed after the end of the callback function it must be cloned inside
435 *  the callback function with skb_clone().
436 *
437 * Return:
438 *  0 on success
439 *  -ENOMEM on missing cache mem to create subscription entry
440 *  -ENODEV unknown device
441 */
442int can_rx_register(struct net *net, struct net_device *dev, canid_t can_id,
443		    canid_t mask, void (*func)(struct sk_buff *, void *),
444		    void *data, char *ident, struct sock *sk)
445{
446	struct receiver *rcv;
447	struct hlist_head *rcv_list;
448	struct can_dev_rcv_lists *dev_rcv_lists;
449	struct can_rcv_lists_stats *rcv_lists_stats = net->can.rcv_lists_stats;
 
450
451	/* insert new receiver  (dev,canid,mask) -> (func,data) */
452
453	if (dev && (dev->type != ARPHRD_CAN || !can_get_ml_priv(dev)))
454		return -ENODEV;
455
456	if (dev && !net_eq(net, dev_net(dev)))
457		return -ENODEV;
458
459	rcv = kmem_cache_alloc(rcv_cache, GFP_KERNEL);
460	if (!rcv)
461		return -ENOMEM;
462
463	spin_lock_bh(&net->can.rcvlists_lock);
464
465	dev_rcv_lists = can_dev_rcv_lists_find(net, dev);
466	rcv_list = can_rcv_list_find(&can_id, &mask, dev_rcv_lists);
467
468	rcv->can_id = can_id;
469	rcv->mask = mask;
470	rcv->matches = 0;
471	rcv->func = func;
472	rcv->data = data;
473	rcv->ident = ident;
474	rcv->sk = sk;
475
476	hlist_add_head_rcu(&rcv->list, rcv_list);
477	dev_rcv_lists->entries++;
478
479	rcv_lists_stats->rcv_entries++;
480	rcv_lists_stats->rcv_entries_max = max(rcv_lists_stats->rcv_entries_max,
481					       rcv_lists_stats->rcv_entries);
482	spin_unlock_bh(&net->can.rcvlists_lock);
483
484	return 0;
485}
486EXPORT_SYMBOL(can_rx_register);
487
488/* can_rx_delete_receiver - rcu callback for single receiver entry removal */
489static void can_rx_delete_receiver(struct rcu_head *rp)
490{
491	struct receiver *rcv = container_of(rp, struct receiver, rcu);
492	struct sock *sk = rcv->sk;
493
494	kmem_cache_free(rcv_cache, rcv);
495	if (sk)
496		sock_put(sk);
497}
498
499/**
500 * can_rx_unregister - unsubscribe CAN frames from a specific interface
501 * @net: the applicable net namespace
502 * @dev: pointer to netdevice (NULL => unsubscribe from 'all' CAN devices list)
503 * @can_id: CAN identifier
504 * @mask: CAN mask
505 * @func: callback function on filter match
506 * @data: returned parameter for callback function
507 *
508 * Description:
509 *  Removes subscription entry depending on given (subscription) values.
510 */
511void can_rx_unregister(struct net *net, struct net_device *dev, canid_t can_id,
512		       canid_t mask, void (*func)(struct sk_buff *, void *),
513		       void *data)
514{
515	struct receiver *rcv = NULL;
516	struct hlist_head *rcv_list;
517	struct can_rcv_lists_stats *rcv_lists_stats = net->can.rcv_lists_stats;
518	struct can_dev_rcv_lists *dev_rcv_lists;
519
520	if (dev && dev->type != ARPHRD_CAN)
521		return;
522
523	if (dev && !net_eq(net, dev_net(dev)))
524		return;
525
526	spin_lock_bh(&net->can.rcvlists_lock);
527
528	dev_rcv_lists = can_dev_rcv_lists_find(net, dev);
529	rcv_list = can_rcv_list_find(&can_id, &mask, dev_rcv_lists);
530
531	/* Search the receiver list for the item to delete.  This should
532	 * exist, since no receiver may be unregistered that hasn't
533	 * been registered before.
534	 */
535	hlist_for_each_entry_rcu(rcv, rcv_list, list) {
536		if (rcv->can_id == can_id && rcv->mask == mask &&
537		    rcv->func == func && rcv->data == data)
538			break;
539	}
540
541	/* Check for bugs in CAN protocol implementations using af_can.c:
542	 * 'rcv' will be NULL if no matching list item was found for removal.
543	 * As this case may potentially happen when closing a socket while
544	 * the notifier for removing the CAN netdev is running we just print
545	 * a warning here.
546	 */
547	if (!rcv) {
548		pr_warn("can: receive list entry not found for dev %s, id %03X, mask %03X\n",
549			DNAME(dev), can_id, mask);
550		goto out;
551	}
552
553	hlist_del_rcu(&rcv->list);
554	dev_rcv_lists->entries--;
555
556	if (rcv_lists_stats->rcv_entries > 0)
557		rcv_lists_stats->rcv_entries--;
558
559 out:
560	spin_unlock_bh(&net->can.rcvlists_lock);
561
562	/* schedule the receiver item for deletion */
563	if (rcv) {
564		if (rcv->sk)
565			sock_hold(rcv->sk);
566		call_rcu(&rcv->rcu, can_rx_delete_receiver);
567	}
568}
569EXPORT_SYMBOL(can_rx_unregister);
570
571static inline void deliver(struct sk_buff *skb, struct receiver *rcv)
572{
573	rcv->func(skb, rcv->data);
574	rcv->matches++;
575}
576
577static int can_rcv_filter(struct can_dev_rcv_lists *dev_rcv_lists, struct sk_buff *skb)
578{
579	struct receiver *rcv;
580	int matches = 0;
581	struct can_frame *cf = (struct can_frame *)skb->data;
582	canid_t can_id = cf->can_id;
583
584	if (dev_rcv_lists->entries == 0)
585		return 0;
586
587	if (can_id & CAN_ERR_FLAG) {
588		/* check for error message frame entries only */
589		hlist_for_each_entry_rcu(rcv, &dev_rcv_lists->rx[RX_ERR], list) {
590			if (can_id & rcv->mask) {
591				deliver(skb, rcv);
592				matches++;
593			}
594		}
595		return matches;
596	}
597
598	/* check for unfiltered entries */
599	hlist_for_each_entry_rcu(rcv, &dev_rcv_lists->rx[RX_ALL], list) {
600		deliver(skb, rcv);
601		matches++;
602	}
603
604	/* check for can_id/mask entries */
605	hlist_for_each_entry_rcu(rcv, &dev_rcv_lists->rx[RX_FIL], list) {
606		if ((can_id & rcv->mask) == rcv->can_id) {
607			deliver(skb, rcv);
608			matches++;
609		}
610	}
611
612	/* check for inverted can_id/mask entries */
613	hlist_for_each_entry_rcu(rcv, &dev_rcv_lists->rx[RX_INV], list) {
614		if ((can_id & rcv->mask) != rcv->can_id) {
615			deliver(skb, rcv);
616			matches++;
617		}
618	}
619
620	/* check filterlists for single non-RTR can_ids */
621	if (can_id & CAN_RTR_FLAG)
622		return matches;
623
624	if (can_id & CAN_EFF_FLAG) {
625		hlist_for_each_entry_rcu(rcv, &dev_rcv_lists->rx_eff[effhash(can_id)], list) {
626			if (rcv->can_id == can_id) {
627				deliver(skb, rcv);
628				matches++;
629			}
630		}
631	} else {
632		can_id &= CAN_SFF_MASK;
633		hlist_for_each_entry_rcu(rcv, &dev_rcv_lists->rx_sff[can_id], list) {
634			deliver(skb, rcv);
635			matches++;
636		}
637	}
638
639	return matches;
640}
641
642static void can_receive(struct sk_buff *skb, struct net_device *dev)
643{
644	struct can_dev_rcv_lists *dev_rcv_lists;
645	struct net *net = dev_net(dev);
646	struct can_pkg_stats *pkg_stats = net->can.pkg_stats;
647	int matches;
648
649	/* update statistics */
650	pkg_stats->rx_frames++;
651	pkg_stats->rx_frames_delta++;
652
653	/* create non-zero unique skb identifier together with *skb */
654	while (!(can_skb_prv(skb)->skbcnt))
655		can_skb_prv(skb)->skbcnt = atomic_inc_return(&skbcounter);
656
657	rcu_read_lock();
658
659	/* deliver the packet to sockets listening on all devices */
660	matches = can_rcv_filter(net->can.rx_alldev_list, skb);
661
662	/* find receive list for this device */
663	dev_rcv_lists = can_dev_rcv_lists_find(net, dev);
664	matches += can_rcv_filter(dev_rcv_lists, skb);
665
666	rcu_read_unlock();
667
668	/* consume the skbuff allocated by the netdevice driver */
669	consume_skb(skb);
670
671	if (matches > 0) {
672		pkg_stats->matches++;
673		pkg_stats->matches_delta++;
674	}
675}
676
677static int can_rcv(struct sk_buff *skb, struct net_device *dev,
678		   struct packet_type *pt, struct net_device *orig_dev)
679{
680	if (unlikely(dev->type != ARPHRD_CAN || !can_get_ml_priv(dev) || !can_is_can_skb(skb))) {
681		pr_warn_once("PF_CAN: dropped non conform CAN skbuff: dev type %d, len %d\n",
682			     dev->type, skb->len);
683
 
 
 
 
684		kfree_skb(skb);
685		return NET_RX_DROP;
686	}
687
688	can_receive(skb, dev);
689	return NET_RX_SUCCESS;
690}
691
692static int canfd_rcv(struct sk_buff *skb, struct net_device *dev,
693		     struct packet_type *pt, struct net_device *orig_dev)
694{
695	if (unlikely(dev->type != ARPHRD_CAN || !can_get_ml_priv(dev) || !can_is_canfd_skb(skb))) {
696		pr_warn_once("PF_CAN: dropped non conform CAN FD skbuff: dev type %d, len %d\n",
697			     dev->type, skb->len);
698
699		kfree_skb(skb);
700		return NET_RX_DROP;
701	}
702
703	can_receive(skb, dev);
704	return NET_RX_SUCCESS;
705}
706
707static int canxl_rcv(struct sk_buff *skb, struct net_device *dev,
708		     struct packet_type *pt, struct net_device *orig_dev)
709{
710	if (unlikely(dev->type != ARPHRD_CAN || !can_get_ml_priv(dev) || !can_is_canxl_skb(skb))) {
711		pr_warn_once("PF_CAN: dropped non conform CAN XL skbuff: dev type %d, len %d\n",
712			     dev->type, skb->len);
713
 
 
 
 
714		kfree_skb(skb);
715		return NET_RX_DROP;
716	}
717
718	can_receive(skb, dev);
719	return NET_RX_SUCCESS;
720}
721
722/* af_can protocol functions */
723
724/**
725 * can_proto_register - register CAN transport protocol
726 * @cp: pointer to CAN protocol structure
727 *
728 * Return:
729 *  0 on success
730 *  -EINVAL invalid (out of range) protocol number
731 *  -EBUSY  protocol already in use
732 *  -ENOBUF if proto_register() fails
733 */
734int can_proto_register(const struct can_proto *cp)
735{
736	int proto = cp->protocol;
737	int err = 0;
738
739	if (proto < 0 || proto >= CAN_NPROTO) {
740		pr_err("can: protocol number %d out of range\n", proto);
741		return -EINVAL;
742	}
743
744	err = proto_register(cp->prot, 0);
745	if (err < 0)
746		return err;
747
748	mutex_lock(&proto_tab_lock);
749
750	if (rcu_access_pointer(proto_tab[proto])) {
751		pr_err("can: protocol %d already registered\n", proto);
752		err = -EBUSY;
753	} else {
754		RCU_INIT_POINTER(proto_tab[proto], cp);
755	}
756
757	mutex_unlock(&proto_tab_lock);
758
759	if (err < 0)
760		proto_unregister(cp->prot);
761
762	return err;
763}
764EXPORT_SYMBOL(can_proto_register);
765
766/**
767 * can_proto_unregister - unregister CAN transport protocol
768 * @cp: pointer to CAN protocol structure
769 */
770void can_proto_unregister(const struct can_proto *cp)
771{
772	int proto = cp->protocol;
773
774	mutex_lock(&proto_tab_lock);
775	BUG_ON(rcu_access_pointer(proto_tab[proto]) != cp);
776	RCU_INIT_POINTER(proto_tab[proto], NULL);
777	mutex_unlock(&proto_tab_lock);
778
779	synchronize_rcu();
780
781	proto_unregister(cp->prot);
782}
783EXPORT_SYMBOL(can_proto_unregister);
784
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
785static int can_pernet_init(struct net *net)
786{
787	spin_lock_init(&net->can.rcvlists_lock);
788	net->can.rx_alldev_list =
789		kzalloc(sizeof(*net->can.rx_alldev_list), GFP_KERNEL);
790	if (!net->can.rx_alldev_list)
791		goto out;
792	net->can.pkg_stats = kzalloc(sizeof(*net->can.pkg_stats), GFP_KERNEL);
793	if (!net->can.pkg_stats)
794		goto out_free_rx_alldev_list;
795	net->can.rcv_lists_stats = kzalloc(sizeof(*net->can.rcv_lists_stats), GFP_KERNEL);
796	if (!net->can.rcv_lists_stats)
797		goto out_free_pkg_stats;
798
799	if (IS_ENABLED(CONFIG_PROC_FS)) {
800		/* the statistics are updated every second (timer triggered) */
801		if (stats_timer) {
802			timer_setup(&net->can.stattimer, can_stat_update,
803				    0);
804			mod_timer(&net->can.stattimer,
805				  round_jiffies(jiffies + HZ));
806		}
807		net->can.pkg_stats->jiffies_init = jiffies;
808		can_init_proc(net);
809	}
810
811	return 0;
812
813 out_free_pkg_stats:
814	kfree(net->can.pkg_stats);
815 out_free_rx_alldev_list:
816	kfree(net->can.rx_alldev_list);
817 out:
818	return -ENOMEM;
819}
820
821static void can_pernet_exit(struct net *net)
822{
823	if (IS_ENABLED(CONFIG_PROC_FS)) {
824		can_remove_proc(net);
825		if (stats_timer)
826			del_timer_sync(&net->can.stattimer);
827	}
828
829	kfree(net->can.rx_alldev_list);
830	kfree(net->can.pkg_stats);
831	kfree(net->can.rcv_lists_stats);
832}
833
834/* af_can module init/exit functions */
835
836static struct packet_type can_packet __read_mostly = {
837	.type = cpu_to_be16(ETH_P_CAN),
838	.func = can_rcv,
839};
840
841static struct packet_type canfd_packet __read_mostly = {
842	.type = cpu_to_be16(ETH_P_CANFD),
843	.func = canfd_rcv,
844};
845
846static struct packet_type canxl_packet __read_mostly = {
847	.type = cpu_to_be16(ETH_P_CANXL),
848	.func = canxl_rcv,
849};
850
851static const struct net_proto_family can_family_ops = {
852	.family = PF_CAN,
853	.create = can_create,
854	.owner  = THIS_MODULE,
855};
856
 
 
 
 
 
857static struct pernet_operations can_pernet_ops __read_mostly = {
858	.init = can_pernet_init,
859	.exit = can_pernet_exit,
860};
861
862static __init int can_init(void)
863{
864	int err;
865
866	/* check for correct padding to be able to use the structs similarly */
867	BUILD_BUG_ON(offsetof(struct can_frame, len) !=
868		     offsetof(struct canfd_frame, len) ||
869		     offsetof(struct can_frame, len) !=
870		     offsetof(struct canxl_frame, flags) ||
871		     offsetof(struct can_frame, data) !=
872		     offsetof(struct canfd_frame, data));
873
874	pr_info("can: controller area network core\n");
875
876	rcv_cache = kmem_cache_create("can_receiver", sizeof(struct receiver),
877				      0, 0, NULL);
878	if (!rcv_cache)
879		return -ENOMEM;
880
881	err = register_pernet_subsys(&can_pernet_ops);
882	if (err)
883		goto out_pernet;
884
885	/* protocol register */
886	err = sock_register(&can_family_ops);
887	if (err)
888		goto out_sock;
 
 
 
889
890	dev_add_pack(&can_packet);
891	dev_add_pack(&canfd_packet);
892	dev_add_pack(&canxl_packet);
893
894	return 0;
895
 
 
896out_sock:
897	unregister_pernet_subsys(&can_pernet_ops);
898out_pernet:
899	kmem_cache_destroy(rcv_cache);
900
901	return err;
902}
903
904static __exit void can_exit(void)
905{
906	/* protocol unregister */
907	dev_remove_pack(&canxl_packet);
908	dev_remove_pack(&canfd_packet);
909	dev_remove_pack(&can_packet);
 
910	sock_unregister(PF_CAN);
911
912	unregister_pernet_subsys(&can_pernet_ops);
913
914	rcu_barrier(); /* Wait for completion of call_rcu()'s */
915
916	kmem_cache_destroy(rcv_cache);
917}
918
919module_init(can_init);
920module_exit(can_exit);