af_can.c

  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	} else {
176		sock_prot_inuse_add(net, sk->sk_prot, 1);
177	}
178
179 errout:
180	can_put_proto(cp);
181	return err;
182}
183
184/* af_can tx path */
185
186/**
187 * can_send - transmit a CAN frame (optional with local loopback)
188 * @skb: pointer to socket buffer with CAN frame in data section
189 * @loop: loopback for listeners on local CAN sockets (recommended default!)
190 *
191 * Due to the loopback this routine must not be called from hardirq context.
192 *
193 * Return:
194 *  0 on success
195 *  -ENETDOWN when the selected interface is down
196 *  -ENOBUFS on full driver queue (see net_xmit_errno())
197 *  -ENOMEM when local loopback failed at calling skb_clone()
198 *  -EPERM when trying to send on a non-CAN interface
199 *  -EMSGSIZE CAN frame size is bigger than CAN interface MTU
200 *  -EINVAL when the skb->data does not contain a valid CAN frame
201 */
202int can_send(struct sk_buff *skb, int loop)
203{
204	struct sk_buff *newskb = NULL;
205	struct can_pkg_stats *pkg_stats = dev_net(skb->dev)->can.pkg_stats;
206	int err = -EINVAL;
207
208	if (can_is_canxl_skb(skb)) {
209		skb->protocol = htons(ETH_P_CANXL);
210	} else if (can_is_can_skb(skb)) {
211		skb->protocol = htons(ETH_P_CAN);
212	} else if (can_is_canfd_skb(skb)) {
213		struct canfd_frame *cfd = (struct canfd_frame *)skb->data;
214
215		skb->protocol = htons(ETH_P_CANFD);
216
217		/* set CAN FD flag for CAN FD frames by default */
218		cfd->flags |= CANFD_FDF;
219	} else {
220		goto inval_skb;
221	}
222
223	/* Make sure the CAN frame can pass the selected CAN netdevice. */
224	if (unlikely(skb->len > READ_ONCE(skb->dev->mtu))) {
225		err = -EMSGSIZE;
226		goto inval_skb;
227	}
228
229	if (unlikely(skb->dev->type != ARPHRD_CAN)) {
230		err = -EPERM;
231		goto inval_skb;
232	}
233
234	if (unlikely(!(skb->dev->flags & IFF_UP))) {
235		err = -ENETDOWN;
236		goto inval_skb;
237	}
238
239	skb->ip_summed = CHECKSUM_UNNECESSARY;
240
241	skb_reset_mac_header(skb);
242	skb_reset_network_header(skb);
243	skb_reset_transport_header(skb);
244
245	if (loop) {
246		/* local loopback of sent CAN frames */
247
248		/* indication for the CAN driver: do loopback */
249		skb->pkt_type = PACKET_LOOPBACK;
250
251		/* The reference to the originating sock may be required
252		 * by the receiving socket to check whether the frame is
253		 * its own. Example: can_raw sockopt CAN_RAW_RECV_OWN_MSGS
254		 * Therefore we have to ensure that skb->sk remains the
255		 * reference to the originating sock by restoring skb->sk
256		 * after each skb_clone() or skb_orphan() usage.
257		 */
258
259		if (!(skb->dev->flags & IFF_ECHO)) {
260			/* If the interface is not capable to do loopback
261			 * itself, we do it here.
262			 */
263			newskb = skb_clone(skb, GFP_ATOMIC);
264			if (!newskb) {
265				kfree_skb(skb);
266				return -ENOMEM;
267			}
268
269			can_skb_set_owner(newskb, skb->sk);
270			newskb->ip_summed = CHECKSUM_UNNECESSARY;
271			newskb->pkt_type = PACKET_BROADCAST;
272		}
273	} else {
274		/* indication for the CAN driver: no loopback required */
275		skb->pkt_type = PACKET_HOST;
276	}
277
278	/* send to netdevice */
279	err = dev_queue_xmit(skb);
280	if (err > 0)
281		err = net_xmit_errno(err);
282
283	if (err) {
284		kfree_skb(newskb);
285		return err;
286	}
287
288	if (newskb)
289		netif_rx(newskb);
290
291	/* update statistics */
292	atomic_long_inc(&pkg_stats->tx_frames);
293	atomic_long_inc(&pkg_stats->tx_frames_delta);
294
295	return 0;
296
297inval_skb:
298	kfree_skb(skb);
299	return err;
300}
301EXPORT_SYMBOL(can_send);
302
303/* af_can rx path */
304
305static struct can_dev_rcv_lists *can_dev_rcv_lists_find(struct net *net,
306							struct net_device *dev)
307{
308	if (dev) {
309		struct can_ml_priv *can_ml = can_get_ml_priv(dev);
310		return &can_ml->dev_rcv_lists;
311	} else {
312		return net->can.rx_alldev_list;
313	}
314}
315
316/**
317 * effhash - hash function for 29 bit CAN identifier reduction
318 * @can_id: 29 bit CAN identifier
319 *
320 * Description:
321 *  To reduce the linear traversal in one linked list of _single_ EFF CAN
322 *  frame subscriptions the 29 bit identifier is mapped to 10 bits.
323 *  (see CAN_EFF_RCV_HASH_BITS definition)
324 *
325 * Return:
326 *  Hash value from 0x000 - 0x3FF ( enforced by CAN_EFF_RCV_HASH_BITS mask )
327 */
328static unsigned int effhash(canid_t can_id)
329{
330	unsigned int hash;
331
332	hash = can_id;
333	hash ^= can_id >> CAN_EFF_RCV_HASH_BITS;
334	hash ^= can_id >> (2 * CAN_EFF_RCV_HASH_BITS);
335
336	return hash & ((1 << CAN_EFF_RCV_HASH_BITS) - 1);
337}
338
339/**
340 * can_rcv_list_find - determine optimal filterlist inside device filter struct
341 * @can_id: pointer to CAN identifier of a given can_filter
342 * @mask: pointer to CAN mask of a given can_filter
343 * @dev_rcv_lists: pointer to the device filter struct
344 *
345 * Description:
346 *  Returns the optimal filterlist to reduce the filter handling in the
347 *  receive path. This function is called by service functions that need
348 *  to register or unregister a can_filter in the filter lists.
349 *
350 *  A filter matches in general, when
351 *
352 *          <received_can_id> & mask == can_id & mask
353 *
354 *  so every bit set in the mask (even CAN_EFF_FLAG, CAN_RTR_FLAG) describe
355 *  relevant bits for the filter.
356 *
357 *  The filter can be inverted (CAN_INV_FILTER bit set in can_id) or it can
358 *  filter for error messages (CAN_ERR_FLAG bit set in mask). For error msg
359 *  frames there is a special filterlist and a special rx path filter handling.
360 *
361 * Return:
362 *  Pointer to optimal filterlist for the given can_id/mask pair.
363 *  Consistency checked mask.
364 *  Reduced can_id to have a preprocessed filter compare value.
365 */
366static struct hlist_head *can_rcv_list_find(canid_t *can_id, canid_t *mask,
367					    struct can_dev_rcv_lists *dev_rcv_lists)
368{
369	canid_t inv = *can_id & CAN_INV_FILTER; /* save flag before masking */
370
371	/* filter for error message frames in extra filterlist */
372	if (*mask & CAN_ERR_FLAG) {
373		/* clear CAN_ERR_FLAG in filter entry */
374		*mask &= CAN_ERR_MASK;
375		return &dev_rcv_lists->rx[RX_ERR];
376	}
377
378	/* with cleared CAN_ERR_FLAG we have a simple mask/value filterpair */
379
380#define CAN_EFF_RTR_FLAGS (CAN_EFF_FLAG | CAN_RTR_FLAG)
381
382	/* ensure valid values in can_mask for 'SFF only' frame filtering */
383	if ((*mask & CAN_EFF_FLAG) && !(*can_id & CAN_EFF_FLAG))
384		*mask &= (CAN_SFF_MASK | CAN_EFF_RTR_FLAGS);
385
386	/* reduce condition testing at receive time */
387	*can_id &= *mask;
388
389	/* inverse can_id/can_mask filter */
390	if (inv)
391		return &dev_rcv_lists->rx[RX_INV];
392
393	/* mask == 0 => no condition testing at receive time */
394	if (!(*mask))
395		return &dev_rcv_lists->rx[RX_ALL];
396
397	/* extra filterlists for the subscription of a single non-RTR can_id */
398	if (((*mask & CAN_EFF_RTR_FLAGS) == CAN_EFF_RTR_FLAGS) &&
399	    !(*can_id & CAN_RTR_FLAG)) {
400		if (*can_id & CAN_EFF_FLAG) {
401			if (*mask == (CAN_EFF_MASK | CAN_EFF_RTR_FLAGS))
402				return &dev_rcv_lists->rx_eff[effhash(*can_id)];
403		} else {
404			if (*mask == (CAN_SFF_MASK | CAN_EFF_RTR_FLAGS))
405				return &dev_rcv_lists->rx_sff[*can_id];
406		}
407	}
408
409	/* default: filter via can_id/can_mask */
410	return &dev_rcv_lists->rx[RX_FIL];
411}
412
413/**
414 * can_rx_register - subscribe CAN frames from a specific interface
415 * @net: the applicable net namespace
416 * @dev: pointer to netdevice (NULL => subscribe from 'all' CAN devices list)
417 * @can_id: CAN identifier (see description)
418 * @mask: CAN mask (see description)
419 * @func: callback function on filter match
420 * @data: returned parameter for callback function
421 * @ident: string for calling module identification
422 * @sk: socket pointer (might be NULL)
423 *
424 * Description:
425 *  Invokes the callback function with the received sk_buff and the given
426 *  parameter 'data' on a matching receive filter. A filter matches, when
427 *
428 *          <received_can_id> & mask == can_id & mask
429 *
430 *  The filter can be inverted (CAN_INV_FILTER bit set in can_id) or it can
431 *  filter for error message frames (CAN_ERR_FLAG bit set in mask).
432 *
433 *  The provided pointer to the sk_buff is guaranteed to be valid as long as
434 *  the callback function is running. The callback function must *not* free
435 *  the given sk_buff while processing it's task. When the given sk_buff is
436 *  needed after the end of the callback function it must be cloned inside
437 *  the callback function with skb_clone().
438 *
439 * Return:
440 *  0 on success
441 *  -ENOMEM on missing cache mem to create subscription entry
442 *  -ENODEV unknown device
443 */
444int can_rx_register(struct net *net, struct net_device *dev, canid_t can_id,
445		    canid_t mask, void (*func)(struct sk_buff *, void *),
446		    void *data, char *ident, struct sock *sk)
447{
448	struct receiver *rcv;
449	struct hlist_head *rcv_list;
450	struct can_dev_rcv_lists *dev_rcv_lists;
451	struct can_rcv_lists_stats *rcv_lists_stats = net->can.rcv_lists_stats;
452
453	/* insert new receiver  (dev,canid,mask) -> (func,data) */
454
455	if (dev && (dev->type != ARPHRD_CAN || !can_get_ml_priv(dev)))
456		return -ENODEV;
457
458	if (dev && !net_eq(net, dev_net(dev)))
459		return -ENODEV;
460
461	rcv = kmem_cache_alloc(rcv_cache, GFP_KERNEL);
462	if (!rcv)
463		return -ENOMEM;
464
465	spin_lock_bh(&net->can.rcvlists_lock);
466
467	dev_rcv_lists = can_dev_rcv_lists_find(net, dev);
468	rcv_list = can_rcv_list_find(&can_id, &mask, dev_rcv_lists);
469
470	rcv->can_id = can_id;
471	rcv->mask = mask;
472	atomic_long_set(&rcv->matches, 0);
473	rcv->func = func;
474	rcv->data = data;
475	rcv->ident = ident;
476	rcv->sk = sk;
477
478	hlist_add_head_rcu(&rcv->list, rcv_list);
479	dev_rcv_lists->entries++;
480
481	rcv_lists_stats->rcv_entries++;
482	rcv_lists_stats->rcv_entries_max = max(rcv_lists_stats->rcv_entries_max,
483					       rcv_lists_stats->rcv_entries);
484	spin_unlock_bh(&net->can.rcvlists_lock);
485
486	return 0;
487}
488EXPORT_SYMBOL(can_rx_register);
489
490/* can_rx_delete_receiver - rcu callback for single receiver entry removal */
491static void can_rx_delete_receiver(struct rcu_head *rp)
492{
493	struct receiver *rcv = container_of(rp, struct receiver, rcu);
494	struct sock *sk = rcv->sk;
495
496	kmem_cache_free(rcv_cache, rcv);
497	if (sk)
498		sock_put(sk);
499}
500
501/**
502 * can_rx_unregister - unsubscribe CAN frames from a specific interface
503 * @net: the applicable net namespace
504 * @dev: pointer to netdevice (NULL => unsubscribe from 'all' CAN devices list)
505 * @can_id: CAN identifier
506 * @mask: CAN mask
507 * @func: callback function on filter match
508 * @data: returned parameter for callback function
509 *
510 * Description:
511 *  Removes subscription entry depending on given (subscription) values.
512 */
513void can_rx_unregister(struct net *net, struct net_device *dev, canid_t can_id,
514		       canid_t mask, void (*func)(struct sk_buff *, void *),
515		       void *data)
516{
517	struct receiver *rcv = NULL;
518	struct hlist_head *rcv_list;
519	struct can_rcv_lists_stats *rcv_lists_stats = net->can.rcv_lists_stats;
520	struct can_dev_rcv_lists *dev_rcv_lists;
521
522	if (dev && dev->type != ARPHRD_CAN)
523		return;
524
525	if (dev && !net_eq(net, dev_net(dev)))
526		return;
527
528	spin_lock_bh(&net->can.rcvlists_lock);
529
530	dev_rcv_lists = can_dev_rcv_lists_find(net, dev);
531	rcv_list = can_rcv_list_find(&can_id, &mask, dev_rcv_lists);
532
533	/* Search the receiver list for the item to delete.  This should
534	 * exist, since no receiver may be unregistered that hasn't
535	 * been registered before.
536	 */
537	hlist_for_each_entry_rcu(rcv, rcv_list, list) {
538		if (rcv->can_id == can_id && rcv->mask == mask &&
539		    rcv->func == func && rcv->data == data)
540			break;
541	}
542
543	/* Check for bugs in CAN protocol implementations using af_can.c:
544	 * 'rcv' will be NULL if no matching list item was found for removal.
545	 * As this case may potentially happen when closing a socket while
546	 * the notifier for removing the CAN netdev is running we just print
547	 * a warning here.
548	 */
549	if (!rcv) {
550		pr_warn("can: receive list entry not found for dev %s, id %03X, mask %03X\n",
551			DNAME(dev), can_id, mask);
552		goto out;
553	}
554
555	hlist_del_rcu(&rcv->list);
556	dev_rcv_lists->entries--;
557
558	if (rcv_lists_stats->rcv_entries > 0)
559		rcv_lists_stats->rcv_entries--;
560
561 out:
562	spin_unlock_bh(&net->can.rcvlists_lock);
563
564	/* schedule the receiver item for deletion */
565	if (rcv) {
566		if (rcv->sk)
567			sock_hold(rcv->sk);
568		call_rcu(&rcv->rcu, can_rx_delete_receiver);
569	}
570}
571EXPORT_SYMBOL(can_rx_unregister);
572
573static inline void deliver(struct sk_buff *skb, struct receiver *rcv)
574{
575	rcv->func(skb, rcv->data);
576	atomic_long_inc(&rcv->matches);
577}
578
579static int can_rcv_filter(struct can_dev_rcv_lists *dev_rcv_lists, struct sk_buff *skb)
580{
581	struct receiver *rcv;
582	int matches = 0;
583	struct can_frame *cf = (struct can_frame *)skb->data;
584	canid_t can_id = cf->can_id;
585
586	if (dev_rcv_lists->entries == 0)
587		return 0;
588
589	if (can_id & CAN_ERR_FLAG) {
590		/* check for error message frame entries only */
591		hlist_for_each_entry_rcu(rcv, &dev_rcv_lists->rx[RX_ERR], list) {
592			if (can_id & rcv->mask) {
593				deliver(skb, rcv);
594				matches++;
595			}
596		}
597		return matches;
598	}
599
600	/* check for unfiltered entries */
601	hlist_for_each_entry_rcu(rcv, &dev_rcv_lists->rx[RX_ALL], list) {
602		deliver(skb, rcv);
603		matches++;
604	}
605
606	/* check for can_id/mask entries */
607	hlist_for_each_entry_rcu(rcv, &dev_rcv_lists->rx[RX_FIL], list) {
608		if ((can_id & rcv->mask) == rcv->can_id) {
609			deliver(skb, rcv);
610			matches++;
611		}
612	}
613
614	/* check for inverted can_id/mask entries */
615	hlist_for_each_entry_rcu(rcv, &dev_rcv_lists->rx[RX_INV], list) {
616		if ((can_id & rcv->mask) != rcv->can_id) {
617			deliver(skb, rcv);
618			matches++;
619		}
620	}
621
622	/* check filterlists for single non-RTR can_ids */
623	if (can_id & CAN_RTR_FLAG)
624		return matches;
625
626	if (can_id & CAN_EFF_FLAG) {
627		hlist_for_each_entry_rcu(rcv, &dev_rcv_lists->rx_eff[effhash(can_id)], list) {
628			if (rcv->can_id == can_id) {
629				deliver(skb, rcv);
630				matches++;
631			}
632		}
633	} else {
634		can_id &= CAN_SFF_MASK;
635		hlist_for_each_entry_rcu(rcv, &dev_rcv_lists->rx_sff[can_id], list) {
636			deliver(skb, rcv);
637			matches++;
638		}
639	}
640
641	return matches;
642}
643
644static void can_receive(struct sk_buff *skb, struct net_device *dev)
645{
646	struct can_dev_rcv_lists *dev_rcv_lists;
647	struct net *net = dev_net(dev);
648	struct can_pkg_stats *pkg_stats = net->can.pkg_stats;
649	int matches;
650
651	/* update statistics */
652	atomic_long_inc(&pkg_stats->rx_frames);
653	atomic_long_inc(&pkg_stats->rx_frames_delta);
654
655	/* create non-zero unique skb identifier together with *skb */
656	while (!(can_skb_prv(skb)->skbcnt))
657		can_skb_prv(skb)->skbcnt = atomic_inc_return(&skbcounter);
658
659	rcu_read_lock();
660
661	/* deliver the packet to sockets listening on all devices */
662	matches = can_rcv_filter(net->can.rx_alldev_list, skb);
663
664	/* find receive list for this device */
665	dev_rcv_lists = can_dev_rcv_lists_find(net, dev);
666	matches += can_rcv_filter(dev_rcv_lists, skb);
667
668	rcu_read_unlock();
669
670	/* consume the skbuff allocated by the netdevice driver */
671	consume_skb(skb);
672
673	if (matches > 0) {
674		atomic_long_inc(&pkg_stats->matches);
675		atomic_long_inc(&pkg_stats->matches_delta);
676	}
677}
678
679static int can_rcv(struct sk_buff *skb, struct net_device *dev,
680		   struct packet_type *pt, struct net_device *orig_dev)
681{
682	if (unlikely(dev->type != ARPHRD_CAN || !can_get_ml_priv(dev) || !can_is_can_skb(skb))) {
683		pr_warn_once("PF_CAN: dropped non conform CAN skbuff: dev type %d, len %d\n",
684			     dev->type, skb->len);
685
686		kfree_skb_reason(skb, SKB_DROP_REASON_CAN_RX_INVALID_FRAME);
687		return NET_RX_DROP;
688	}
689
690	can_receive(skb, dev);
691	return NET_RX_SUCCESS;
692}
693
694static int canfd_rcv(struct sk_buff *skb, struct net_device *dev,
695		     struct packet_type *pt, struct net_device *orig_dev)
696{
697	if (unlikely(dev->type != ARPHRD_CAN || !can_get_ml_priv(dev) || !can_is_canfd_skb(skb))) {
698		pr_warn_once("PF_CAN: dropped non conform CAN FD skbuff: dev type %d, len %d\n",
699			     dev->type, skb->len);
700
701		kfree_skb_reason(skb, SKB_DROP_REASON_CANFD_RX_INVALID_FRAME);
702		return NET_RX_DROP;
703	}
704
705	can_receive(skb, dev);
706	return NET_RX_SUCCESS;
707}
708
709static int canxl_rcv(struct sk_buff *skb, struct net_device *dev,
710		     struct packet_type *pt, struct net_device *orig_dev)
711{
712	if (unlikely(dev->type != ARPHRD_CAN || !can_get_ml_priv(dev) || !can_is_canxl_skb(skb))) {
713		pr_warn_once("PF_CAN: dropped non conform CAN XL skbuff: dev type %d, len %d\n",
714			     dev->type, skb->len);
715
716		kfree_skb_reason(skb, SKB_DROP_REASON_CANXL_RX_INVALID_FRAME);
717		return NET_RX_DROP;
718	}
719
720	can_receive(skb, dev);
721	return NET_RX_SUCCESS;
722}
723
724/* af_can protocol functions */
725
726/**
727 * can_proto_register - register CAN transport protocol
728 * @cp: pointer to CAN protocol structure
729 *
730 * Return:
731 *  0 on success
732 *  -EINVAL invalid (out of range) protocol number
733 *  -EBUSY  protocol already in use
734 *  -ENOBUF if proto_register() fails
735 */
736int can_proto_register(const struct can_proto *cp)
737{
738	int proto = cp->protocol;
739	int err = 0;
740
741	if (proto < 0 || proto >= CAN_NPROTO) {
742		pr_err("can: protocol number %d out of range\n", proto);
743		return -EINVAL;
744	}
745
746	err = proto_register(cp->prot, 0);
747	if (err < 0)
748		return err;
749
750	mutex_lock(&proto_tab_lock);
751
752	if (rcu_access_pointer(proto_tab[proto])) {
753		pr_err("can: protocol %d already registered\n", proto);
754		err = -EBUSY;
755	} else {
756		RCU_INIT_POINTER(proto_tab[proto], cp);
757	}
758
759	mutex_unlock(&proto_tab_lock);
760
761	if (err < 0)
762		proto_unregister(cp->prot);
763
764	return err;
765}
766EXPORT_SYMBOL(can_proto_register);
767
768/**
769 * can_proto_unregister - unregister CAN transport protocol
770 * @cp: pointer to CAN protocol structure
771 */
772void can_proto_unregister(const struct can_proto *cp)
773{
774	int proto = cp->protocol;
775
776	mutex_lock(&proto_tab_lock);
777	BUG_ON(rcu_access_pointer(proto_tab[proto]) != cp);
778	RCU_INIT_POINTER(proto_tab[proto], NULL);
779	mutex_unlock(&proto_tab_lock);
780
781	synchronize_rcu();
782
783	proto_unregister(cp->prot);
784}
785EXPORT_SYMBOL(can_proto_unregister);
786
787static int can_pernet_init(struct net *net)
788{
789	spin_lock_init(&net->can.rcvlists_lock);
790	net->can.rx_alldev_list =
791		kzalloc(sizeof(*net->can.rx_alldev_list), GFP_KERNEL);
792	if (!net->can.rx_alldev_list)
793		goto out;
794	net->can.pkg_stats = kzalloc(sizeof(*net->can.pkg_stats), GFP_KERNEL);
795	if (!net->can.pkg_stats)
796		goto out_free_rx_alldev_list;
797	net->can.rcv_lists_stats = kzalloc(sizeof(*net->can.rcv_lists_stats), GFP_KERNEL);
798	if (!net->can.rcv_lists_stats)
799		goto out_free_pkg_stats;
800
801	if (IS_ENABLED(CONFIG_PROC_FS)) {
802		/* the statistics are updated every second (timer triggered) */
803		if (stats_timer) {
804			timer_setup(&net->can.stattimer, can_stat_update,
805				    0);
806			mod_timer(&net->can.stattimer,
807				  round_jiffies(jiffies + HZ));
808		}
809		net->can.pkg_stats->jiffies_init = jiffies;
810		can_init_proc(net);
811	}
812
813	return 0;
814
815 out_free_pkg_stats:
816	kfree(net->can.pkg_stats);
817 out_free_rx_alldev_list:
818	kfree(net->can.rx_alldev_list);
819 out:
820	return -ENOMEM;
821}
822
823static void can_pernet_exit(struct net *net)
824{
825	if (IS_ENABLED(CONFIG_PROC_FS)) {
826		can_remove_proc(net);
827		if (stats_timer)
828			timer_delete_sync(&net->can.stattimer);
829	}
830
831	kfree(net->can.rx_alldev_list);
832	kfree(net->can.pkg_stats);
833	kfree(net->can.rcv_lists_stats);
834}
835
836/* af_can module init/exit functions */
837
838static struct packet_type can_packet __read_mostly = {
839	.type = cpu_to_be16(ETH_P_CAN),
840	.func = can_rcv,
841};
842
843static struct packet_type canfd_packet __read_mostly = {
844	.type = cpu_to_be16(ETH_P_CANFD),
845	.func = canfd_rcv,
846};
847
848static struct packet_type canxl_packet __read_mostly = {
849	.type = cpu_to_be16(ETH_P_CANXL),
850	.func = canxl_rcv,
851};
852
853static const struct net_proto_family can_family_ops = {
854	.family = PF_CAN,
855	.create = can_create,
856	.owner  = THIS_MODULE,
857};
858
859static struct pernet_operations can_pernet_ops __read_mostly = {
860	.init = can_pernet_init,
861	.exit = can_pernet_exit,
862};
863
864static __init int can_init(void)
865{
866	int err;
867
868	/* check for correct padding to be able to use the structs similarly */
869	BUILD_BUG_ON(offsetof(struct can_frame, len) !=
870		     offsetof(struct canfd_frame, len) ||
871		     offsetof(struct can_frame, len) !=
872		     offsetof(struct canxl_frame, flags) ||
873		     offsetof(struct can_frame, data) !=
874		     offsetof(struct canfd_frame, data));
875
876	pr_info("can: controller area network core\n");
877
878	rcv_cache = kmem_cache_create("can_receiver", sizeof(struct receiver),
879				      0, 0, NULL);
880	if (!rcv_cache)
881		return -ENOMEM;
882
883	err = register_pernet_subsys(&can_pernet_ops);
884	if (err)
885		goto out_pernet;
886
887	/* protocol register */
888	err = sock_register(&can_family_ops);
889	if (err)
890		goto out_sock;
891
892	dev_add_pack(&can_packet);
893	dev_add_pack(&canfd_packet);
894	dev_add_pack(&canxl_packet);
895
896	return 0;
897
898out_sock:
899	unregister_pernet_subsys(&can_pernet_ops);
900out_pernet:
901	kmem_cache_destroy(rcv_cache);
902
903	return err;
904}
905
906static __exit void can_exit(void)
907{
908	/* protocol unregister */
909	dev_remove_pack(&canxl_packet);
910	dev_remove_pack(&canfd_packet);
911	dev_remove_pack(&can_packet);
912	sock_unregister(PF_CAN);
913
914	unregister_pernet_subsys(&can_pernet_ops);
915
916	rcu_barrier(); /* Wait for completion of call_rcu()'s */
917
918	kmem_cache_destroy(rcv_cache);
919}
920
921module_init(can_init);
922module_exit(can_exit);