af_can.c 23.7 KB
Newer Older
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43
/*
 * af_can.c - Protocol family CAN core module
 *            (used by different CAN protocol modules)
 *
 * Copyright (c) 2002-2007 Volkswagen Group Electronic Research
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of Volkswagen nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * Alternatively, provided that this notice is retained in full, this
 * software may be distributed under the terms of the GNU General
 * Public License ("GPL") version 2, in which case the provisions of the
 * GPL apply INSTEAD OF those given above.
 *
 * The provided data structures and external interfaces from this code
 * are not restricted to be used by modules with a GPL compatible license.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
 * DAMAGE.
 *
 */

#include <linux/module.h>
44
#include <linux/stddef.h>
45 46 47 48 49 50 51 52 53 54 55 56 57 58 59
#include <linux/init.h>
#include <linux/kmod.h>
#include <linux/slab.h>
#include <linux/list.h>
#include <linux/spinlock.h>
#include <linux/rcupdate.h>
#include <linux/uaccess.h>
#include <linux/net.h>
#include <linux/netdevice.h>
#include <linux/socket.h>
#include <linux/if_ether.h>
#include <linux/if_arp.h>
#include <linux/skbuff.h>
#include <linux/can.h>
#include <linux/can/core.h>
60
#include <linux/can/skb.h>
61
#include <linux/ratelimit.h>
62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77
#include <net/net_namespace.h>
#include <net/sock.h>

#include "af_can.h"

MODULE_DESCRIPTION("Controller Area Network PF_CAN core");
MODULE_LICENSE("Dual BSD/GPL");
MODULE_AUTHOR("Urs Thuermann <urs.thuermann@volkswagen.de>, "
	      "Oliver Hartkopp <oliver.hartkopp@volkswagen.de>");

MODULE_ALIAS_NETPROTO(PF_CAN);

static int stats_timer __read_mostly = 1;
module_param(stats_timer, int, S_IRUGO);
MODULE_PARM_DESC(stats_timer, "enable timer for statistics (default:on)");

78 79
/* receive filters subscribed for 'all' CAN devices */
struct dev_rcv_lists can_rx_alldev_list;
80 81 82 83 84
static DEFINE_SPINLOCK(can_rcvlists_lock);

static struct kmem_cache *rcv_cache __read_mostly;

/* table of registered CAN protocols */
85
static const struct can_proto *proto_tab[CAN_NPROTO] __read_mostly;
86
static DEFINE_MUTEX(proto_tab_lock);
87 88 89 90 91 92 93 94 95

struct timer_list can_stattimer;   /* timer for statistics update */
struct s_stats    can_stats;       /* packet statistics */
struct s_pstats   can_pstats;      /* receive list statistics */

/*
 * af_can socket functions
 */

Oliver Hartkopp's avatar
Oliver Hartkopp committed
96
int can_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
97 98 99 100 101 102 103 104 105 106 107 108
{
	struct sock *sk = sock->sk;

	switch (cmd) {

	case SIOCGSTAMP:
		return sock_get_timestamp(sk, (struct timeval __user *)arg);

	default:
		return -ENOIOCTLCMD;
	}
}
Oliver Hartkopp's avatar
Oliver Hartkopp committed
109
EXPORT_SYMBOL(can_ioctl);
110 111 112 113 114 115

static void can_sock_destruct(struct sock *sk)
{
	skb_queue_purge(&sk->sk_receive_queue);
}

116
static const struct can_proto *can_get_proto(int protocol)
117
{
118
	const struct can_proto *cp;
119 120 121 122 123 124 125 126 127 128

	rcu_read_lock();
	cp = rcu_dereference(proto_tab[protocol]);
	if (cp && !try_module_get(cp->prot->owner))
		cp = NULL;
	rcu_read_unlock();

	return cp;
}

129 130 131 132 133
static inline void can_put_proto(const struct can_proto *cp)
{
	module_put(cp->prot->owner);
}

134 135
static int can_create(struct net *net, struct socket *sock, int protocol,
		      int kern)
136 137
{
	struct sock *sk;
138
	const struct can_proto *cp;
139 140 141 142 143 144 145
	int err = 0;

	sock->state = SS_UNCONNECTED;

	if (protocol < 0 || protocol >= CAN_NPROTO)
		return -EINVAL;

146
	if (!net_eq(net, &init_net))
147 148
		return -EAFNOSUPPORT;

149
	cp = can_get_proto(protocol);
150

151
#ifdef CONFIG_MODULES
152 153 154
	if (!cp) {
		/* try to load protocol module if kernel is modular */

155
		err = request_module("can-proto-%d", protocol);
156 157 158 159 160 161

		/*
		 * In case of error we only print a message but don't
		 * return the error code immediately.  Below we will
		 * return -EPROTONOSUPPORT
		 */
162 163
		if (err)
			printk_ratelimited(KERN_ERR "can: request_module "
164
			       "(can-proto-%d) failed.\n", protocol);
165

166
		cp = can_get_proto(protocol);
167
	}
168
#endif
169 170 171 172 173 174 175

	/* check for available protocol and correct usage */

	if (!cp)
		return -EPROTONOSUPPORT;

	if (cp->type != sock->type) {
176
		err = -EPROTOTYPE;
177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200
		goto errout;
	}

	sock->ops = cp->ops;

	sk = sk_alloc(net, PF_CAN, GFP_KERNEL, cp->prot);
	if (!sk) {
		err = -ENOMEM;
		goto errout;
	}

	sock_init_data(sock, sk);
	sk->sk_destruct = can_sock_destruct;

	if (sk->sk_prot->init)
		err = sk->sk_prot->init(sk);

	if (err) {
		/* release sk on errors */
		sock_orphan(sk);
		sock_put(sk);
	}

 errout:
201
	can_put_proto(cp);
202 203 204 205 206 207 208 209 210 211 212 213
	return err;
}

/*
 * af_can tx path
 */

/**
 * can_send - transmit a CAN frame (optional with local loopback)
 * @skb: pointer to socket buffer with CAN frame in data section
 * @loop: loopback for listeners on local CAN sockets (recommended default!)
 *
214 215
 * Due to the loopback this routine must not be called from hardirq context.
 *
216 217 218 219 220 221
 * Return:
 *  0 on success
 *  -ENETDOWN when the selected interface is down
 *  -ENOBUFS on full driver queue (see net_xmit_errno())
 *  -ENOMEM when local loopback failed at calling skb_clone()
 *  -EPERM when trying to send on a non-CAN interface
222
 *  -EMSGSIZE CAN frame size is bigger than CAN interface MTU
Oliver Hartkopp's avatar
Oliver Hartkopp committed
223
 *  -EINVAL when the skb->data does not contain a valid CAN frame
224 225 226
 */
int can_send(struct sk_buff *skb, int loop)
{
227
	struct sk_buff *newskb = NULL;
228 229 230 231 232 233 234 235 236 237 238 239 240
	struct canfd_frame *cfd = (struct canfd_frame *)skb->data;
	int err = -EINVAL;

	if (skb->len == CAN_MTU) {
		skb->protocol = htons(ETH_P_CAN);
		if (unlikely(cfd->len > CAN_MAX_DLEN))
			goto inval_skb;
	} else if (skb->len == CANFD_MTU) {
		skb->protocol = htons(ETH_P_CANFD);
		if (unlikely(cfd->len > CANFD_MAX_DLEN))
			goto inval_skb;
	} else
		goto inval_skb;
241

242 243 244 245 246 247 248 249
	/*
	 * Make sure the CAN frame can pass the selected CAN netdevice.
	 * As structs can_frame and canfd_frame are similar, we can provide
	 * CAN FD frames to legacy CAN drivers as long as the length is <= 8
	 */
	if (unlikely(skb->len > skb->dev->mtu && cfd->len > CAN_MAX_DLEN)) {
		err = -EMSGSIZE;
		goto inval_skb;
Oliver Hartkopp's avatar
Oliver Hartkopp committed
250 251
	}

252 253 254
	if (unlikely(skb->dev->type != ARPHRD_CAN)) {
		err = -EPERM;
		goto inval_skb;
255 256
	}

257 258 259
	if (unlikely(!(skb->dev->flags & IFF_UP))) {
		err = -ENETDOWN;
		goto inval_skb;
260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284
	}

	skb_reset_network_header(skb);
	skb_reset_transport_header(skb);

	if (loop) {
		/* local loopback of sent CAN frames */

		/* indication for the CAN driver: do loopback */
		skb->pkt_type = PACKET_LOOPBACK;

		/*
		 * The reference to the originating sock may be required
		 * by the receiving socket to check whether the frame is
		 * its own. Example: can_raw sockopt CAN_RAW_RECV_OWN_MSGS
		 * Therefore we have to ensure that skb->sk remains the
		 * reference to the originating sock by restoring skb->sk
		 * after each skb_clone() or skb_orphan() usage.
		 */

		if (!(skb->dev->flags & IFF_ECHO)) {
			/*
			 * If the interface is not capable to do loopback
			 * itself, we do it here.
			 */
285
			newskb = skb_clone(skb, GFP_ATOMIC);
286 287 288 289 290
			if (!newskb) {
				kfree_skb(skb);
				return -ENOMEM;
			}

291
			can_skb_set_owner(newskb, skb->sk);
292 293 294 295 296 297 298 299 300 301 302 303 304
			newskb->ip_summed = CHECKSUM_UNNECESSARY;
			newskb->pkt_type = PACKET_BROADCAST;
		}
	} else {
		/* indication for the CAN driver: no loopback required */
		skb->pkt_type = PACKET_HOST;
	}

	/* send to netdevice */
	err = dev_queue_xmit(skb);
	if (err > 0)
		err = net_xmit_errno(err);

305
	if (err) {
306
		kfree_skb(newskb);
307 308 309 310
		return err;
	}

	if (newskb)
311
		netif_rx_ni(newskb);
312

313 314 315 316
	/* update statistics */
	can_stats.tx_frames++;
	can_stats.tx_frames_delta++;

317
	return 0;
318 319 320 321

inval_skb:
	kfree_skb(skb);
	return err;
322 323 324 325 326 327 328 329 330
}
EXPORT_SYMBOL(can_send);

/*
 * af_can rx path
 */

static struct dev_rcv_lists *find_dev_rcv_lists(struct net_device *dev)
{
331 332 333 334
	if (!dev)
		return &can_rx_alldev_list;
	else
		return (struct dev_rcv_lists *)dev->ml_priv;
335 336
}

337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359
/**
 * effhash - hash function for 29 bit CAN identifier reduction
 * @can_id: 29 bit CAN identifier
 *
 * Description:
 *  To reduce the linear traversal in one linked list of _single_ EFF CAN
 *  frame subscriptions the 29 bit identifier is mapped to 10 bits.
 *  (see CAN_EFF_RCV_HASH_BITS definition)
 *
 * Return:
 *  Hash value from 0x000 - 0x3FF ( enforced by CAN_EFF_RCV_HASH_BITS mask )
 */
static unsigned int effhash(canid_t can_id)
{
	unsigned int hash;

	hash = can_id;
	hash ^= can_id >> CAN_EFF_RCV_HASH_BITS;
	hash ^= can_id >> (2 * CAN_EFF_RCV_HASH_BITS);

	return hash & ((1 << CAN_EFF_RCV_HASH_BITS) - 1);
}

360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378
/**
 * find_rcv_list - determine optimal filterlist inside device filter struct
 * @can_id: pointer to CAN identifier of a given can_filter
 * @mask: pointer to CAN mask of a given can_filter
 * @d: pointer to the device filter struct
 *
 * Description:
 *  Returns the optimal filterlist to reduce the filter handling in the
 *  receive path. This function is called by service functions that need
 *  to register or unregister a can_filter in the filter lists.
 *
 *  A filter matches in general, when
 *
 *          <received_can_id> & mask == can_id & mask
 *
 *  so every bit set in the mask (even CAN_EFF_FLAG, CAN_RTR_FLAG) describe
 *  relevant bits for the filter.
 *
 *  The filter can be inverted (CAN_INV_FILTER bit set in can_id) or it can
379 380
 *  filter for error messages (CAN_ERR_FLAG bit set in mask). For error msg
 *  frames there is a special filterlist and a special rx path filter handling.
381 382 383 384 385 386
 *
 * Return:
 *  Pointer to optimal filterlist for the given can_id/mask pair.
 *  Constistency checked mask.
 *  Reduced can_id to have a preprocessed filter compare value.
 */
387 388 389 390 391
static struct hlist_head *find_rcv_list(canid_t *can_id, canid_t *mask,
					struct dev_rcv_lists *d)
{
	canid_t inv = *can_id & CAN_INV_FILTER; /* save flag before masking */

392
	/* filter for error message frames in extra filterlist */
393
	if (*mask & CAN_ERR_FLAG) {
394
		/* clear CAN_ERR_FLAG in filter entry */
395 396 397 398
		*mask &= CAN_ERR_MASK;
		return &d->rx[RX_ERR];
	}

399 400 401 402 403 404 405
	/* with cleared CAN_ERR_FLAG we have a simple mask/value filterpair */

#define CAN_EFF_RTR_FLAGS (CAN_EFF_FLAG | CAN_RTR_FLAG)

	/* ensure valid values in can_mask for 'SFF only' frame filtering */
	if ((*mask & CAN_EFF_FLAG) && !(*can_id & CAN_EFF_FLAG))
		*mask &= (CAN_SFF_MASK | CAN_EFF_RTR_FLAGS);
406 407 408 409 410 411 412 413 414 415 416 417

	/* reduce condition testing at receive time */
	*can_id &= *mask;

	/* inverse can_id/can_mask filter */
	if (inv)
		return &d->rx[RX_INV];

	/* mask == 0 => no condition testing at receive time */
	if (!(*mask))
		return &d->rx[RX_ALL];

418
	/* extra filterlists for the subscription of a single non-RTR can_id */
419 420
	if (((*mask & CAN_EFF_RTR_FLAGS) == CAN_EFF_RTR_FLAGS) &&
	    !(*can_id & CAN_RTR_FLAG)) {
421 422

		if (*can_id & CAN_EFF_FLAG) {
423 424
			if (*mask == (CAN_EFF_MASK | CAN_EFF_RTR_FLAGS))
				return &d->rx_eff[effhash(*can_id)];
425 426 427
		} else {
			if (*mask == (CAN_SFF_MASK | CAN_EFF_RTR_FLAGS))
				return &d->rx_sff[*can_id];
428 429 430 431 432 433 434 435 436 437 438 439 440 441
		}
	}

	/* default: filter via can_id/can_mask */
	return &d->rx[RX_FIL];
}

/**
 * can_rx_register - subscribe CAN frames from a specific interface
 * @dev: pointer to netdevice (NULL => subcribe from 'all' CAN devices list)
 * @can_id: CAN identifier (see description)
 * @mask: CAN mask (see description)
 * @func: callback function on filter match
 * @data: returned parameter for callback function
442
 * @ident: string for calling module identification
443 444 445 446 447 448 449 450
 *
 * Description:
 *  Invokes the callback function with the received sk_buff and the given
 *  parameter 'data' on a matching receive filter. A filter matches, when
 *
 *          <received_can_id> & mask == can_id & mask
 *
 *  The filter can be inverted (CAN_INV_FILTER bit set in can_id) or it can
451
 *  filter for error message frames (CAN_ERR_FLAG bit set in mask).
452
 *
453 454 455 456 457 458
 *  The provided pointer to the sk_buff is guaranteed to be valid as long as
 *  the callback function is running. The callback function must *not* free
 *  the given sk_buff while processing it's task. When the given sk_buff is
 *  needed after the end of the callback function it must be cloned inside
 *  the callback function with skb_clone().
 *
459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474
 * Return:
 *  0 on success
 *  -ENOMEM on missing cache mem to create subscription entry
 *  -ENODEV unknown device
 */
int can_rx_register(struct net_device *dev, canid_t can_id, canid_t mask,
		    void (*func)(struct sk_buff *, void *), void *data,
		    char *ident)
{
	struct receiver *r;
	struct hlist_head *rl;
	struct dev_rcv_lists *d;
	int err = 0;

	/* insert new receiver  (dev,canid,mask) -> (func,data) */

475 476 477
	if (dev && dev->type != ARPHRD_CAN)
		return -ENODEV;

478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523
	r = kmem_cache_alloc(rcv_cache, GFP_KERNEL);
	if (!r)
		return -ENOMEM;

	spin_lock(&can_rcvlists_lock);

	d = find_dev_rcv_lists(dev);
	if (d) {
		rl = find_rcv_list(&can_id, &mask, d);

		r->can_id  = can_id;
		r->mask    = mask;
		r->matches = 0;
		r->func    = func;
		r->data    = data;
		r->ident   = ident;

		hlist_add_head_rcu(&r->list, rl);
		d->entries++;

		can_pstats.rcv_entries++;
		if (can_pstats.rcv_entries_max < can_pstats.rcv_entries)
			can_pstats.rcv_entries_max = can_pstats.rcv_entries;
	} else {
		kmem_cache_free(rcv_cache, r);
		err = -ENODEV;
	}

	spin_unlock(&can_rcvlists_lock);

	return err;
}
EXPORT_SYMBOL(can_rx_register);

/*
 * can_rx_delete_receiver - rcu callback for single receiver entry removal
 */
static void can_rx_delete_receiver(struct rcu_head *rp)
{
	struct receiver *r = container_of(rp, struct receiver, rcu);

	kmem_cache_free(rcv_cache, r);
}

/**
 * can_rx_unregister - unsubscribe CAN frames from a specific interface
Jeremiah Mahler's avatar
Jeremiah Mahler committed
524
 * @dev: pointer to netdevice (NULL => unsubscribe from 'all' CAN devices list)
525 526 527 528 529 530 531 532 533 534 535 536 537 538 539
 * @can_id: CAN identifier
 * @mask: CAN mask
 * @func: callback function on filter match
 * @data: returned parameter for callback function
 *
 * Description:
 *  Removes subscription entry depending on given (subscription) values.
 */
void can_rx_unregister(struct net_device *dev, canid_t can_id, canid_t mask,
		       void (*func)(struct sk_buff *, void *), void *data)
{
	struct receiver *r = NULL;
	struct hlist_head *rl;
	struct dev_rcv_lists *d;

540 541 542
	if (dev && dev->type != ARPHRD_CAN)
		return;

543 544 545 546
	spin_lock(&can_rcvlists_lock);

	d = find_dev_rcv_lists(dev);
	if (!d) {
547
		pr_err("BUG: receive list not found for "
548 549 550 551 552 553 554 555 556 557 558 559 560
		       "dev %s, id %03X, mask %03X\n",
		       DNAME(dev), can_id, mask);
		goto out;
	}

	rl = find_rcv_list(&can_id, &mask, d);

	/*
	 * Search the receiver list for the item to delete.  This should
	 * exist, since no receiver may be unregistered that hasn't
	 * been registered before.
	 */

561
	hlist_for_each_entry_rcu(r, rl, list) {
562 563
		if (r->can_id == can_id && r->mask == mask &&
		    r->func == func && r->data == data)
564 565 566 567
			break;
	}

	/*
568 569
	 * Check for bugs in CAN protocol implementations using af_can.c:
	 * 'r' will be NULL if no matching list item was found for removal.
570 571
	 */

572
	if (!r) {
573 574
		WARN(1, "BUG: receive list entry not found for dev %s, "
		     "id %03X, mask %03X\n", DNAME(dev), can_id, mask);
575 576 577 578 579 580 581 582 583 584
		goto out;
	}

	hlist_del_rcu(&r->list);
	d->entries--;

	if (can_pstats.rcv_entries > 0)
		can_pstats.rcv_entries--;

	/* remove device structure requested by NETDEV_UNREGISTER */
585 586 587 588
	if (d->remove_on_zero_entries && !d->entries) {
		kfree(d);
		dev->ml_priv = NULL;
	}
589 590 591 592 593 594 595 596 597 598 599 600

 out:
	spin_unlock(&can_rcvlists_lock);

	/* schedule the receiver item for deletion */
	if (r)
		call_rcu(&r->rcu, can_rx_delete_receiver);
}
EXPORT_SYMBOL(can_rx_unregister);

static inline void deliver(struct sk_buff *skb, struct receiver *r)
{
601 602
	r->func(skb, r->data);
	r->matches++;
603 604 605 606 607 608 609 610 611 612 613 614 615
}

static int can_rcv_filter(struct dev_rcv_lists *d, struct sk_buff *skb)
{
	struct receiver *r;
	int matches = 0;
	struct can_frame *cf = (struct can_frame *)skb->data;
	canid_t can_id = cf->can_id;

	if (d->entries == 0)
		return 0;

	if (can_id & CAN_ERR_FLAG) {
616
		/* check for error message frame entries only */
617
		hlist_for_each_entry_rcu(r, &d->rx[RX_ERR], list) {
618 619 620 621 622 623 624 625 626
			if (can_id & r->mask) {
				deliver(skb, r);
				matches++;
			}
		}
		return matches;
	}

	/* check for unfiltered entries */
627
	hlist_for_each_entry_rcu(r, &d->rx[RX_ALL], list) {
628 629 630 631 632
		deliver(skb, r);
		matches++;
	}

	/* check for can_id/mask entries */
633
	hlist_for_each_entry_rcu(r, &d->rx[RX_FIL], list) {
634 635 636 637 638 639 640
		if ((can_id & r->mask) == r->can_id) {
			deliver(skb, r);
			matches++;
		}
	}

	/* check for inverted can_id/mask entries */
641
	hlist_for_each_entry_rcu(r, &d->rx[RX_INV], list) {
642 643 644 645 646 647
		if ((can_id & r->mask) != r->can_id) {
			deliver(skb, r);
			matches++;
		}
	}

648 649 650 651
	/* check filterlists for single non-RTR can_ids */
	if (can_id & CAN_RTR_FLAG)
		return matches;

652
	if (can_id & CAN_EFF_FLAG) {
653
		hlist_for_each_entry_rcu(r, &d->rx_eff[effhash(can_id)], list) {
654 655 656 657 658 659 660
			if (r->can_id == can_id) {
				deliver(skb, r);
				matches++;
			}
		}
	} else {
		can_id &= CAN_SFF_MASK;
661
		hlist_for_each_entry_rcu(r, &d->rx_sff[can_id], list) {
662 663 664 665 666 667 668 669
			deliver(skb, r);
			matches++;
		}
	}

	return matches;
}

670
static void can_receive(struct sk_buff *skb, struct net_device *dev)
671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690
{
	struct dev_rcv_lists *d;
	int matches;

	/* update statistics */
	can_stats.rx_frames++;
	can_stats.rx_frames_delta++;

	rcu_read_lock();

	/* deliver the packet to sockets listening on all devices */
	matches = can_rcv_filter(&can_rx_alldev_list, skb);

	/* find receive list for this device */
	d = find_dev_rcv_lists(dev);
	if (d)
		matches += can_rcv_filter(d, skb);

	rcu_read_unlock();

691 692
	/* consume the skbuff allocated by the netdevice driver */
	consume_skb(skb);
693 694 695 696 697

	if (matches > 0) {
		can_stats.matches++;
		can_stats.matches_delta++;
	}
698 699 700 701 702 703
}

static int can_rcv(struct sk_buff *skb, struct net_device *dev,
		   struct packet_type *pt, struct net_device *orig_dev)
{
	struct canfd_frame *cfd = (struct canfd_frame *)skb->data;
704

705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740
	if (unlikely(!net_eq(dev_net(dev), &init_net)))
		goto drop;

	if (WARN_ONCE(dev->type != ARPHRD_CAN ||
		      skb->len != CAN_MTU ||
		      cfd->len > CAN_MAX_DLEN,
		      "PF_CAN: dropped non conform CAN skbuf: "
		      "dev type %d, len %d, datalen %d\n",
		      dev->type, skb->len, cfd->len))
		goto drop;

	can_receive(skb, dev);
	return NET_RX_SUCCESS;

drop:
	kfree_skb(skb);
	return NET_RX_DROP;
}

static int canfd_rcv(struct sk_buff *skb, struct net_device *dev,
		   struct packet_type *pt, struct net_device *orig_dev)
{
	struct canfd_frame *cfd = (struct canfd_frame *)skb->data;

	if (unlikely(!net_eq(dev_net(dev), &init_net)))
		goto drop;

	if (WARN_ONCE(dev->type != ARPHRD_CAN ||
		      skb->len != CANFD_MTU ||
		      cfd->len > CANFD_MAX_DLEN,
		      "PF_CAN: dropped non conform CAN FD skbuf: "
		      "dev type %d, len %d, datalen %d\n",
		      dev->type, skb->len, cfd->len))
		goto drop;

	can_receive(skb, dev);
741
	return NET_RX_SUCCESS;
742 743 744

drop:
	kfree_skb(skb);
745
	return NET_RX_DROP;
746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761
}

/*
 * af_can protocol functions
 */

/**
 * can_proto_register - register CAN transport protocol
 * @cp: pointer to CAN protocol structure
 *
 * Return:
 *  0 on success
 *  -EINVAL invalid (out of range) protocol number
 *  -EBUSY  protocol already in use
 *  -ENOBUF if proto_register() fails
 */
762
int can_proto_register(const struct can_proto *cp)
763 764 765 766 767
{
	int proto = cp->protocol;
	int err = 0;

	if (proto < 0 || proto >= CAN_NPROTO) {
768
		pr_err("can: protocol number %d out of range\n", proto);
769 770 771
		return -EINVAL;
	}

772 773 774 775
	err = proto_register(cp->prot, 0);
	if (err < 0)
		return err;

776 777
	mutex_lock(&proto_tab_lock);

778
	if (proto_tab[proto]) {
779
		pr_err("can: protocol %d already registered\n", proto);
780
		err = -EBUSY;
Oliver Hartkopp's avatar
Oliver Hartkopp committed
781
	} else
782
		RCU_INIT_POINTER(proto_tab[proto], cp);
783

784
	mutex_unlock(&proto_tab_lock);
785 786

	if (err < 0)
787
		proto_unregister(cp->prot);
788 789 790 791 792 793 794 795 796

	return err;
}
EXPORT_SYMBOL(can_proto_register);

/**
 * can_proto_unregister - unregister CAN transport protocol
 * @cp: pointer to CAN protocol structure
 */
797
void can_proto_unregister(const struct can_proto *cp)
798 799 800
{
	int proto = cp->protocol;

801 802
	mutex_lock(&proto_tab_lock);
	BUG_ON(proto_tab[proto] != cp);
803
	RCU_INIT_POINTER(proto_tab[proto], NULL);
804 805 806
	mutex_unlock(&proto_tab_lock);

	synchronize_rcu();
807 808

	proto_unregister(cp->prot);
809 810 811 812 813 814 815
}
EXPORT_SYMBOL(can_proto_unregister);

/*
 * af_can notifier to create/remove CAN netdevice specific structs
 */
static int can_notifier(struct notifier_block *nb, unsigned long msg,
816
			void *ptr)
817
{
818
	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
819 820
	struct dev_rcv_lists *d;

821
	if (!net_eq(dev_net(dev), &init_net))
822 823 824 825 826 827 828 829 830
		return NOTIFY_DONE;

	if (dev->type != ARPHRD_CAN)
		return NOTIFY_DONE;

	switch (msg) {

	case NETDEV_REGISTER:

831
		/* create new dev_rcv_lists for this device */
832
		d = kzalloc(sizeof(*d), GFP_KERNEL);
833
		if (!d)
834
			return NOTIFY_DONE;
835 836
		BUG_ON(dev->ml_priv);
		dev->ml_priv = d;
837 838 839 840 841 842

		break;

	case NETDEV_UNREGISTER:
		spin_lock(&can_rcvlists_lock);

843
		d = dev->ml_priv;
844
		if (d) {
845
			if (d->entries)
846
				d->remove_on_zero_entries = 1;
847 848 849 850
			else {
				kfree(d);
				dev->ml_priv = NULL;
			}
851
		} else
852 853
			pr_err("can: notifier: receive list not found for dev "
			       "%s\n", dev->name);
854 855 856 857 858 859 860 861 862 863 864 865 866 867

		spin_unlock(&can_rcvlists_lock);

		break;
	}

	return NOTIFY_DONE;
}

/*
 * af_can module init/exit functions
 */

static struct packet_type can_packet __read_mostly = {
868
	.type = cpu_to_be16(ETH_P_CAN),
869 870 871
	.func = can_rcv,
};

872 873 874 875 876
static struct packet_type canfd_packet __read_mostly = {
	.type = cpu_to_be16(ETH_P_CANFD),
	.func = canfd_rcv,
};

877
static const struct net_proto_family can_family_ops = {
878 879 880 881 882 883 884 885 886 887 888 889
	.family = PF_CAN,
	.create = can_create,
	.owner  = THIS_MODULE,
};

/* notifier block for netdevice event */
static struct notifier_block can_netdev_notifier __read_mostly = {
	.notifier_call = can_notifier,
};

static __init int can_init(void)
{
890 891 892 893 894 895
	/* check for correct padding to be able to use the structs similarly */
	BUILD_BUG_ON(offsetof(struct can_frame, can_dlc) !=
		     offsetof(struct canfd_frame, len) ||
		     offsetof(struct can_frame, data) !=
		     offsetof(struct canfd_frame, data));

896
	pr_info("can: controller area network core (" CAN_VERSION_STRING ")\n");
897

898 899
	memset(&can_rx_alldev_list, 0, sizeof(can_rx_alldev_list));

900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917
	rcv_cache = kmem_cache_create("can_receiver", sizeof(struct receiver),
				      0, 0, NULL);
	if (!rcv_cache)
		return -ENOMEM;

	if (stats_timer) {
		/* the statistics are updated every second (timer triggered) */
		setup_timer(&can_stattimer, can_stat_update, 0);
		mod_timer(&can_stattimer, round_jiffies(jiffies + HZ));
	} else
		can_stattimer.function = NULL;

	can_init_proc();

	/* protocol register */
	sock_register(&can_family_ops);
	register_netdevice_notifier(&can_netdev_notifier);
	dev_add_pack(&can_packet);
918
	dev_add_pack(&canfd_packet);
919 920 921 922 923 924

	return 0;
}

static __exit void can_exit(void)
{
925
	struct net_device *dev;
926 927

	if (stats_timer)
928
		del_timer_sync(&can_stattimer);
929 930 931 932

	can_remove_proc();

	/* protocol unregister */
933
	dev_remove_pack(&canfd_packet);
934 935 936 937
	dev_remove_pack(&can_packet);
	unregister_netdevice_notifier(&can_netdev_notifier);
	sock_unregister(PF_CAN);

938 939 940
	/* remove created dev_rcv_lists from still registered CAN devices */
	rcu_read_lock();
	for_each_netdev_rcu(&init_net, dev) {
941
		if (dev->type == ARPHRD_CAN && dev->ml_priv) {
942 943 944 945 946 947 948

			struct dev_rcv_lists *d = dev->ml_priv;

			BUG_ON(d->entries);
			kfree(d);
			dev->ml_priv = NULL;
		}
949
	}
950
	rcu_read_unlock();
951

952 953
	rcu_barrier(); /* Wait for completion of call_rcu()'s */

954 955 956 957 958
	kmem_cache_destroy(rcv_cache);
}

module_init(can_init);
module_exit(can_exit);