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