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 66 static __initdata const char banner[] = KERN_INFO 67 "can: controller area network core (" CAN_VERSION_STRING ")\n"; 68 69 MODULE_DESCRIPTION("Controller Area Network PF_CAN core"); 70 MODULE_LICENSE("Dual BSD/GPL"); 71 MODULE_AUTHOR("Urs Thuermann <urs.thuermann@volkswagen.de>, " 72 "Oliver Hartkopp <oliver.hartkopp@volkswagen.de>"); 73 74 MODULE_ALIAS_NETPROTO(PF_CAN); 75 76 static int stats_timer __read_mostly = 1; 77 module_param(stats_timer, int, S_IRUGO); 78 MODULE_PARM_DESC(stats_timer, "enable timer for statistics (default:on)"); 79 80 /* receive filters subscribed for 'all' CAN devices */ 81 struct dev_rcv_lists can_rx_alldev_list; 82 static DEFINE_SPINLOCK(can_rcvlists_lock); 83 84 static struct kmem_cache *rcv_cache __read_mostly; 85 86 /* table of registered CAN protocols */ 87 static const struct can_proto *proto_tab[CAN_NPROTO] __read_mostly; 88 static DEFINE_MUTEX(proto_tab_lock); 89 90 struct timer_list can_stattimer; /* timer for statistics update */ 91 struct s_stats can_stats; /* packet statistics */ 92 struct s_pstats can_pstats; /* receive list statistics */ 93 94 /* 95 * af_can socket functions 96 */ 97 98 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 EXPORT_SYMBOL(can_ioctl); 112 113 static void can_sock_destruct(struct sock *sk) 114 { 115 skb_queue_purge(&sk->sk_receive_queue); 116 } 117 118 static const struct can_proto *can_get_proto(int protocol) 119 { 120 const struct can_proto *cp; 121 122 rcu_read_lock(); 123 cp = rcu_dereference(proto_tab[protocol]); 124 if (cp && !try_module_get(cp->prot->owner)) 125 cp = NULL; 126 rcu_read_unlock(); 127 128 return cp; 129 } 130 131 static inline void can_put_proto(const struct can_proto *cp) 132 { 133 module_put(cp->prot->owner); 134 } 135 136 static int can_create(struct net *net, struct socket *sock, int protocol, 137 int kern) 138 { 139 struct sock *sk; 140 const struct can_proto *cp; 141 int err = 0; 142 143 sock->state = SS_UNCONNECTED; 144 145 if (protocol < 0 || protocol >= CAN_NPROTO) 146 return -EINVAL; 147 148 if (!net_eq(net, &init_net)) 149 return -EAFNOSUPPORT; 150 151 cp = can_get_proto(protocol); 152 153 #ifdef CONFIG_MODULES 154 if (!cp) { 155 /* try to load protocol module if kernel is modular */ 156 157 err = request_module("can-proto-%d", protocol); 158 159 /* 160 * In case of error we only print a message but don't 161 * return the error code immediately. Below we will 162 * return -EPROTONOSUPPORT 163 */ 164 if (err && printk_ratelimit()) 165 printk(KERN_ERR "can: request_module " 166 "(can-proto-%d) failed.\n", protocol); 167 168 cp = can_get_proto(protocol); 169 } 170 #endif 171 172 /* check for available protocol and correct usage */ 173 174 if (!cp) 175 return -EPROTONOSUPPORT; 176 177 if (cp->type != sock->type) { 178 err = -EPROTOTYPE; 179 goto errout; 180 } 181 182 sock->ops = cp->ops; 183 184 sk = sk_alloc(net, PF_CAN, GFP_KERNEL, cp->prot); 185 if (!sk) { 186 err = -ENOMEM; 187 goto errout; 188 } 189 190 sock_init_data(sock, sk); 191 sk->sk_destruct = can_sock_destruct; 192 193 if (sk->sk_prot->init) 194 err = sk->sk_prot->init(sk); 195 196 if (err) { 197 /* release sk on errors */ 198 sock_orphan(sk); 199 sock_put(sk); 200 } 201 202 errout: 203 can_put_proto(cp); 204 return err; 205 } 206 207 /* 208 * af_can tx path 209 */ 210 211 /** 212 * can_send - transmit a CAN frame (optional with local loopback) 213 * @skb: pointer to socket buffer with CAN frame in data section 214 * @loop: loopback for listeners on local CAN sockets (recommended default!) 215 * 216 * Due to the loopback this routine must not be called from hardirq context. 217 * 218 * Return: 219 * 0 on success 220 * -ENETDOWN when the selected interface is down 221 * -ENOBUFS on full driver queue (see net_xmit_errno()) 222 * -ENOMEM when local loopback failed at calling skb_clone() 223 * -EPERM when trying to send on a non-CAN interface 224 * -EINVAL when the skb->data does not contain a valid CAN frame 225 */ 226 int can_send(struct sk_buff *skb, int loop) 227 { 228 struct sk_buff *newskb = NULL; 229 struct can_frame *cf = (struct can_frame *)skb->data; 230 int err; 231 232 if (skb->len != sizeof(struct can_frame) || cf->can_dlc > 8) { 233 kfree_skb(skb); 234 return -EINVAL; 235 } 236 237 if (skb->dev->type != ARPHRD_CAN) { 238 kfree_skb(skb); 239 return -EPERM; 240 } 241 242 if (!(skb->dev->flags & IFF_UP)) { 243 kfree_skb(skb); 244 return -ENETDOWN; 245 } 246 247 skb->protocol = htons(ETH_P_CAN); 248 skb_reset_network_header(skb); 249 skb_reset_transport_header(skb); 250 251 if (loop) { 252 /* local loopback of sent CAN frames */ 253 254 /* indication for the CAN driver: do loopback */ 255 skb->pkt_type = PACKET_LOOPBACK; 256 257 /* 258 * The reference to the originating sock may be required 259 * by the receiving socket to check whether the frame is 260 * its own. Example: can_raw sockopt CAN_RAW_RECV_OWN_MSGS 261 * Therefore we have to ensure that skb->sk remains the 262 * reference to the originating sock by restoring skb->sk 263 * after each skb_clone() or skb_orphan() usage. 264 */ 265 266 if (!(skb->dev->flags & IFF_ECHO)) { 267 /* 268 * If the interface is not capable to do loopback 269 * itself, we do it here. 270 */ 271 newskb = skb_clone(skb, GFP_ATOMIC); 272 if (!newskb) { 273 kfree_skb(skb); 274 return -ENOMEM; 275 } 276 277 newskb->sk = skb->sk; 278 newskb->ip_summed = CHECKSUM_UNNECESSARY; 279 newskb->pkt_type = PACKET_BROADCAST; 280 } 281 } else { 282 /* indication for the CAN driver: no loopback required */ 283 skb->pkt_type = PACKET_HOST; 284 } 285 286 /* send to netdevice */ 287 err = dev_queue_xmit(skb); 288 if (err > 0) 289 err = net_xmit_errno(err); 290 291 if (err) { 292 kfree_skb(newskb); 293 return err; 294 } 295 296 if (newskb) 297 netif_rx_ni(newskb); 298 299 /* update statistics */ 300 can_stats.tx_frames++; 301 can_stats.tx_frames_delta++; 302 303 return 0; 304 } 305 EXPORT_SYMBOL(can_send); 306 307 /* 308 * af_can rx path 309 */ 310 311 static struct dev_rcv_lists *find_dev_rcv_lists(struct net_device *dev) 312 { 313 if (!dev) 314 return &can_rx_alldev_list; 315 else 316 return (struct dev_rcv_lists *)dev->ml_priv; 317 } 318 319 /** 320 * find_rcv_list - determine optimal filterlist inside device filter struct 321 * @can_id: pointer to CAN identifier of a given can_filter 322 * @mask: pointer to CAN mask of a given can_filter 323 * @d: pointer to the device filter struct 324 * 325 * Description: 326 * Returns the optimal filterlist to reduce the filter handling in the 327 * receive path. This function is called by service functions that need 328 * to register or unregister a can_filter in the filter lists. 329 * 330 * A filter matches in general, when 331 * 332 * <received_can_id> & mask == can_id & mask 333 * 334 * so every bit set in the mask (even CAN_EFF_FLAG, CAN_RTR_FLAG) describe 335 * relevant bits for the filter. 336 * 337 * The filter can be inverted (CAN_INV_FILTER bit set in can_id) or it can 338 * filter for error frames (CAN_ERR_FLAG bit set in mask). For error frames 339 * there is a special filterlist and a special rx path filter handling. 340 * 341 * Return: 342 * Pointer to optimal filterlist for the given can_id/mask pair. 343 * Constistency checked mask. 344 * Reduced can_id to have a preprocessed filter compare value. 345 */ 346 static struct hlist_head *find_rcv_list(canid_t *can_id, canid_t *mask, 347 struct dev_rcv_lists *d) 348 { 349 canid_t inv = *can_id & CAN_INV_FILTER; /* save flag before masking */ 350 351 /* filter for error frames in extra filterlist */ 352 if (*mask & CAN_ERR_FLAG) { 353 /* clear CAN_ERR_FLAG in filter entry */ 354 *mask &= CAN_ERR_MASK; 355 return &d->rx[RX_ERR]; 356 } 357 358 /* with cleared CAN_ERR_FLAG we have a simple mask/value filterpair */ 359 360 #define CAN_EFF_RTR_FLAGS (CAN_EFF_FLAG | CAN_RTR_FLAG) 361 362 /* ensure valid values in can_mask for 'SFF only' frame filtering */ 363 if ((*mask & CAN_EFF_FLAG) && !(*can_id & CAN_EFF_FLAG)) 364 *mask &= (CAN_SFF_MASK | CAN_EFF_RTR_FLAGS); 365 366 /* reduce condition testing at receive time */ 367 *can_id &= *mask; 368 369 /* inverse can_id/can_mask filter */ 370 if (inv) 371 return &d->rx[RX_INV]; 372 373 /* mask == 0 => no condition testing at receive time */ 374 if (!(*mask)) 375 return &d->rx[RX_ALL]; 376 377 /* extra filterlists for the subscription of a single non-RTR can_id */ 378 if (((*mask & CAN_EFF_RTR_FLAGS) == CAN_EFF_RTR_FLAGS) && 379 !(*can_id & CAN_RTR_FLAG)) { 380 381 if (*can_id & CAN_EFF_FLAG) { 382 if (*mask == (CAN_EFF_MASK | CAN_EFF_RTR_FLAGS)) { 383 /* RFC: a future use-case for hash-tables? */ 384 return &d->rx[RX_EFF]; 385 } 386 } else { 387 if (*mask == (CAN_SFF_MASK | CAN_EFF_RTR_FLAGS)) 388 return &d->rx_sff[*can_id]; 389 } 390 } 391 392 /* default: filter via can_id/can_mask */ 393 return &d->rx[RX_FIL]; 394 } 395 396 /** 397 * can_rx_register - subscribe CAN frames from a specific interface 398 * @dev: pointer to netdevice (NULL => subcribe from 'all' CAN devices list) 399 * @can_id: CAN identifier (see description) 400 * @mask: CAN mask (see description) 401 * @func: callback function on filter match 402 * @data: returned parameter for callback function 403 * @ident: string for calling module indentification 404 * 405 * Description: 406 * Invokes the callback function with the received sk_buff and the given 407 * parameter 'data' on a matching receive filter. A filter matches, when 408 * 409 * <received_can_id> & mask == can_id & mask 410 * 411 * The filter can be inverted (CAN_INV_FILTER bit set in can_id) or it can 412 * filter for error frames (CAN_ERR_FLAG bit set in mask). 413 * 414 * The provided pointer to the sk_buff is guaranteed to be valid as long as 415 * the callback function is running. The callback function must *not* free 416 * the given sk_buff while processing it's task. When the given sk_buff is 417 * needed after the end of the callback function it must be cloned inside 418 * the callback function with skb_clone(). 419 * 420 * Return: 421 * 0 on success 422 * -ENOMEM on missing cache mem to create subscription entry 423 * -ENODEV unknown device 424 */ 425 int can_rx_register(struct net_device *dev, canid_t can_id, canid_t mask, 426 void (*func)(struct sk_buff *, void *), void *data, 427 char *ident) 428 { 429 struct receiver *r; 430 struct hlist_head *rl; 431 struct dev_rcv_lists *d; 432 int err = 0; 433 434 /* insert new receiver (dev,canid,mask) -> (func,data) */ 435 436 if (dev && dev->type != ARPHRD_CAN) 437 return -ENODEV; 438 439 r = kmem_cache_alloc(rcv_cache, GFP_KERNEL); 440 if (!r) 441 return -ENOMEM; 442 443 spin_lock(&can_rcvlists_lock); 444 445 d = find_dev_rcv_lists(dev); 446 if (d) { 447 rl = find_rcv_list(&can_id, &mask, d); 448 449 r->can_id = can_id; 450 r->mask = mask; 451 r->matches = 0; 452 r->func = func; 453 r->data = data; 454 r->ident = ident; 455 456 hlist_add_head_rcu(&r->list, rl); 457 d->entries++; 458 459 can_pstats.rcv_entries++; 460 if (can_pstats.rcv_entries_max < can_pstats.rcv_entries) 461 can_pstats.rcv_entries_max = can_pstats.rcv_entries; 462 } else { 463 kmem_cache_free(rcv_cache, r); 464 err = -ENODEV; 465 } 466 467 spin_unlock(&can_rcvlists_lock); 468 469 return err; 470 } 471 EXPORT_SYMBOL(can_rx_register); 472 473 /* 474 * can_rx_delete_receiver - rcu callback for single receiver entry removal 475 */ 476 static void can_rx_delete_receiver(struct rcu_head *rp) 477 { 478 struct receiver *r = container_of(rp, struct receiver, rcu); 479 480 kmem_cache_free(rcv_cache, r); 481 } 482 483 /** 484 * can_rx_unregister - unsubscribe CAN frames from a specific interface 485 * @dev: pointer to netdevice (NULL => unsubcribe from 'all' CAN devices list) 486 * @can_id: CAN identifier 487 * @mask: CAN mask 488 * @func: callback function on filter match 489 * @data: returned parameter for callback function 490 * 491 * Description: 492 * Removes subscription entry depending on given (subscription) values. 493 */ 494 void can_rx_unregister(struct net_device *dev, canid_t can_id, canid_t mask, 495 void (*func)(struct sk_buff *, void *), void *data) 496 { 497 struct receiver *r = NULL; 498 struct hlist_head *rl; 499 struct hlist_node *next; 500 struct dev_rcv_lists *d; 501 502 if (dev && dev->type != ARPHRD_CAN) 503 return; 504 505 spin_lock(&can_rcvlists_lock); 506 507 d = find_dev_rcv_lists(dev); 508 if (!d) { 509 printk(KERN_ERR "BUG: receive list not found for " 510 "dev %s, id %03X, mask %03X\n", 511 DNAME(dev), can_id, mask); 512 goto out; 513 } 514 515 rl = find_rcv_list(&can_id, &mask, d); 516 517 /* 518 * Search the receiver list for the item to delete. This should 519 * exist, since no receiver may be unregistered that hasn't 520 * been registered before. 521 */ 522 523 hlist_for_each_entry_rcu(r, next, rl, list) { 524 if (r->can_id == can_id && r->mask == mask && 525 r->func == func && r->data == data) 526 break; 527 } 528 529 /* 530 * Check for bugs in CAN protocol implementations: 531 * If no matching list item was found, the list cursor variable next 532 * will be NULL, while r will point to the last item of the list. 533 */ 534 535 if (!next) { 536 printk(KERN_ERR "BUG: receive list entry not found for " 537 "dev %s, id %03X, mask %03X\n", 538 DNAME(dev), can_id, mask); 539 r = NULL; 540 goto out; 541 } 542 543 hlist_del_rcu(&r->list); 544 d->entries--; 545 546 if (can_pstats.rcv_entries > 0) 547 can_pstats.rcv_entries--; 548 549 /* remove device structure requested by NETDEV_UNREGISTER */ 550 if (d->remove_on_zero_entries && !d->entries) { 551 kfree(d); 552 dev->ml_priv = NULL; 553 } 554 555 out: 556 spin_unlock(&can_rcvlists_lock); 557 558 /* schedule the receiver item for deletion */ 559 if (r) 560 call_rcu(&r->rcu, can_rx_delete_receiver); 561 } 562 EXPORT_SYMBOL(can_rx_unregister); 563 564 static inline void deliver(struct sk_buff *skb, struct receiver *r) 565 { 566 r->func(skb, r->data); 567 r->matches++; 568 } 569 570 static int can_rcv_filter(struct dev_rcv_lists *d, struct sk_buff *skb) 571 { 572 struct receiver *r; 573 struct hlist_node *n; 574 int matches = 0; 575 struct can_frame *cf = (struct can_frame *)skb->data; 576 canid_t can_id = cf->can_id; 577 578 if (d->entries == 0) 579 return 0; 580 581 if (can_id & CAN_ERR_FLAG) { 582 /* check for error frame entries only */ 583 hlist_for_each_entry_rcu(r, n, &d->rx[RX_ERR], list) { 584 if (can_id & r->mask) { 585 deliver(skb, r); 586 matches++; 587 } 588 } 589 return matches; 590 } 591 592 /* check for unfiltered entries */ 593 hlist_for_each_entry_rcu(r, n, &d->rx[RX_ALL], list) { 594 deliver(skb, r); 595 matches++; 596 } 597 598 /* check for can_id/mask entries */ 599 hlist_for_each_entry_rcu(r, n, &d->rx[RX_FIL], list) { 600 if ((can_id & r->mask) == r->can_id) { 601 deliver(skb, r); 602 matches++; 603 } 604 } 605 606 /* check for inverted can_id/mask entries */ 607 hlist_for_each_entry_rcu(r, n, &d->rx[RX_INV], list) { 608 if ((can_id & r->mask) != r->can_id) { 609 deliver(skb, r); 610 matches++; 611 } 612 } 613 614 /* check filterlists for single non-RTR can_ids */ 615 if (can_id & CAN_RTR_FLAG) 616 return matches; 617 618 if (can_id & CAN_EFF_FLAG) { 619 hlist_for_each_entry_rcu(r, n, &d->rx[RX_EFF], list) { 620 if (r->can_id == can_id) { 621 deliver(skb, r); 622 matches++; 623 } 624 } 625 } else { 626 can_id &= CAN_SFF_MASK; 627 hlist_for_each_entry_rcu(r, n, &d->rx_sff[can_id], list) { 628 deliver(skb, r); 629 matches++; 630 } 631 } 632 633 return matches; 634 } 635 636 static int can_rcv(struct sk_buff *skb, struct net_device *dev, 637 struct packet_type *pt, struct net_device *orig_dev) 638 { 639 struct dev_rcv_lists *d; 640 struct can_frame *cf = (struct can_frame *)skb->data; 641 int matches; 642 643 if (!net_eq(dev_net(dev), &init_net)) 644 goto drop; 645 646 if (WARN_ONCE(dev->type != ARPHRD_CAN || 647 skb->len != sizeof(struct can_frame) || 648 cf->can_dlc > 8, 649 "PF_CAN: dropped non conform skbuf: " 650 "dev type %d, len %d, can_dlc %d\n", 651 dev->type, skb->len, cf->can_dlc)) 652 goto drop; 653 654 /* update statistics */ 655 can_stats.rx_frames++; 656 can_stats.rx_frames_delta++; 657 658 rcu_read_lock(); 659 660 /* deliver the packet to sockets listening on all devices */ 661 matches = can_rcv_filter(&can_rx_alldev_list, skb); 662 663 /* find receive list for this device */ 664 d = find_dev_rcv_lists(dev); 665 if (d) 666 matches += can_rcv_filter(d, 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 can_stats.matches++; 675 can_stats.matches_delta++; 676 } 677 678 return NET_RX_SUCCESS; 679 680 drop: 681 kfree_skb(skb); 682 return NET_RX_DROP; 683 } 684 685 /* 686 * af_can protocol functions 687 */ 688 689 /** 690 * can_proto_register - register CAN transport protocol 691 * @cp: pointer to CAN protocol structure 692 * 693 * Return: 694 * 0 on success 695 * -EINVAL invalid (out of range) protocol number 696 * -EBUSY protocol already in use 697 * -ENOBUF if proto_register() fails 698 */ 699 int can_proto_register(const struct can_proto *cp) 700 { 701 int proto = cp->protocol; 702 int err = 0; 703 704 if (proto < 0 || proto >= CAN_NPROTO) { 705 printk(KERN_ERR "can: protocol number %d out of range\n", 706 proto); 707 return -EINVAL; 708 } 709 710 err = proto_register(cp->prot, 0); 711 if (err < 0) 712 return err; 713 714 mutex_lock(&proto_tab_lock); 715 716 if (proto_tab[proto]) { 717 printk(KERN_ERR "can: protocol %d already registered\n", 718 proto); 719 err = -EBUSY; 720 } else 721 rcu_assign_pointer(proto_tab[proto], cp); 722 723 mutex_unlock(&proto_tab_lock); 724 725 if (err < 0) 726 proto_unregister(cp->prot); 727 728 return err; 729 } 730 EXPORT_SYMBOL(can_proto_register); 731 732 /** 733 * can_proto_unregister - unregister CAN transport protocol 734 * @cp: pointer to CAN protocol structure 735 */ 736 void can_proto_unregister(const struct can_proto *cp) 737 { 738 int proto = cp->protocol; 739 740 mutex_lock(&proto_tab_lock); 741 BUG_ON(proto_tab[proto] != cp); 742 rcu_assign_pointer(proto_tab[proto], NULL); 743 mutex_unlock(&proto_tab_lock); 744 745 synchronize_rcu(); 746 747 proto_unregister(cp->prot); 748 } 749 EXPORT_SYMBOL(can_proto_unregister); 750 751 /* 752 * af_can notifier to create/remove CAN netdevice specific structs 753 */ 754 static int can_notifier(struct notifier_block *nb, unsigned long msg, 755 void *data) 756 { 757 struct net_device *dev = (struct net_device *)data; 758 struct dev_rcv_lists *d; 759 760 if (!net_eq(dev_net(dev), &init_net)) 761 return NOTIFY_DONE; 762 763 if (dev->type != ARPHRD_CAN) 764 return NOTIFY_DONE; 765 766 switch (msg) { 767 768 case NETDEV_REGISTER: 769 770 /* create new dev_rcv_lists for this device */ 771 d = kzalloc(sizeof(*d), GFP_KERNEL); 772 if (!d) { 773 printk(KERN_ERR 774 "can: allocation of receive list failed\n"); 775 return NOTIFY_DONE; 776 } 777 BUG_ON(dev->ml_priv); 778 dev->ml_priv = d; 779 780 break; 781 782 case NETDEV_UNREGISTER: 783 spin_lock(&can_rcvlists_lock); 784 785 d = dev->ml_priv; 786 if (d) { 787 if (d->entries) 788 d->remove_on_zero_entries = 1; 789 else { 790 kfree(d); 791 dev->ml_priv = NULL; 792 } 793 } else 794 printk(KERN_ERR "can: notifier: receive list not " 795 "found for dev %s\n", dev->name); 796 797 spin_unlock(&can_rcvlists_lock); 798 799 break; 800 } 801 802 return NOTIFY_DONE; 803 } 804 805 /* 806 * af_can module init/exit functions 807 */ 808 809 static struct packet_type can_packet __read_mostly = { 810 .type = cpu_to_be16(ETH_P_CAN), 811 .dev = NULL, 812 .func = can_rcv, 813 }; 814 815 static const struct net_proto_family can_family_ops = { 816 .family = PF_CAN, 817 .create = can_create, 818 .owner = THIS_MODULE, 819 }; 820 821 /* notifier block for netdevice event */ 822 static struct notifier_block can_netdev_notifier __read_mostly = { 823 .notifier_call = can_notifier, 824 }; 825 826 static __init int can_init(void) 827 { 828 printk(banner); 829 830 memset(&can_rx_alldev_list, 0, sizeof(can_rx_alldev_list)); 831 832 rcv_cache = kmem_cache_create("can_receiver", sizeof(struct receiver), 833 0, 0, NULL); 834 if (!rcv_cache) 835 return -ENOMEM; 836 837 if (stats_timer) { 838 /* the statistics are updated every second (timer triggered) */ 839 setup_timer(&can_stattimer, can_stat_update, 0); 840 mod_timer(&can_stattimer, round_jiffies(jiffies + HZ)); 841 } else 842 can_stattimer.function = NULL; 843 844 can_init_proc(); 845 846 /* protocol register */ 847 sock_register(&can_family_ops); 848 register_netdevice_notifier(&can_netdev_notifier); 849 dev_add_pack(&can_packet); 850 851 return 0; 852 } 853 854 static __exit void can_exit(void) 855 { 856 struct net_device *dev; 857 858 if (stats_timer) 859 del_timer(&can_stattimer); 860 861 can_remove_proc(); 862 863 /* protocol unregister */ 864 dev_remove_pack(&can_packet); 865 unregister_netdevice_notifier(&can_netdev_notifier); 866 sock_unregister(PF_CAN); 867 868 /* remove created dev_rcv_lists from still registered CAN devices */ 869 rcu_read_lock(); 870 for_each_netdev_rcu(&init_net, dev) { 871 if (dev->type == ARPHRD_CAN && dev->ml_priv){ 872 873 struct dev_rcv_lists *d = dev->ml_priv; 874 875 BUG_ON(d->entries); 876 kfree(d); 877 dev->ml_priv = NULL; 878 } 879 } 880 rcu_read_unlock(); 881 882 rcu_barrier(); /* Wait for completion of call_rcu()'s */ 883 884 kmem_cache_destroy(rcv_cache); 885 } 886 887 module_init(can_init); 888 module_exit(can_exit); 889