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 HLIST_HEAD(can_rx_dev_list); 81 static 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 static 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 } 111 112 static void can_sock_destruct(struct sock *sk) 113 { 114 skb_queue_purge(&sk->sk_receive_queue); 115 } 116 117 static int can_create(struct net *net, struct socket *sock, int protocol) 118 { 119 struct sock *sk; 120 struct can_proto *cp; 121 int err = 0; 122 123 sock->state = SS_UNCONNECTED; 124 125 if (protocol < 0 || protocol >= CAN_NPROTO) 126 return -EINVAL; 127 128 if (net != &init_net) 129 return -EAFNOSUPPORT; 130 131 #ifdef CONFIG_MODULES 132 /* try to load protocol module kernel is modular */ 133 if (!proto_tab[protocol]) { 134 err = request_module("can-proto-%d", protocol); 135 136 /* 137 * In case of error we only print a message but don't 138 * return the error code immediately. Below we will 139 * return -EPROTONOSUPPORT 140 */ 141 if (err && printk_ratelimit()) 142 printk(KERN_ERR "can: request_module " 143 "(can-proto-%d) failed.\n", protocol); 144 } 145 #endif 146 147 spin_lock(&proto_tab_lock); 148 cp = proto_tab[protocol]; 149 if (cp && !try_module_get(cp->prot->owner)) 150 cp = NULL; 151 spin_unlock(&proto_tab_lock); 152 153 /* check for available protocol and correct usage */ 154 155 if (!cp) 156 return -EPROTONOSUPPORT; 157 158 if (cp->type != sock->type) { 159 err = -EPROTONOSUPPORT; 160 goto errout; 161 } 162 163 if (cp->capability >= 0 && !capable(cp->capability)) { 164 err = -EPERM; 165 goto errout; 166 } 167 168 sock->ops = cp->ops; 169 170 sk = sk_alloc(net, PF_CAN, GFP_KERNEL, cp->prot); 171 if (!sk) { 172 err = -ENOMEM; 173 goto errout; 174 } 175 176 sock_init_data(sock, sk); 177 sk->sk_destruct = can_sock_destruct; 178 179 if (sk->sk_prot->init) 180 err = sk->sk_prot->init(sk); 181 182 if (err) { 183 /* release sk on errors */ 184 sock_orphan(sk); 185 sock_put(sk); 186 } 187 188 errout: 189 module_put(cp->prot->owner); 190 return err; 191 } 192 193 /* 194 * af_can tx path 195 */ 196 197 /** 198 * can_send - transmit a CAN frame (optional with local loopback) 199 * @skb: pointer to socket buffer with CAN frame in data section 200 * @loop: loopback for listeners on local CAN sockets (recommended default!) 201 * 202 * Return: 203 * 0 on success 204 * -ENETDOWN when the selected interface is down 205 * -ENOBUFS on full driver queue (see net_xmit_errno()) 206 * -ENOMEM when local loopback failed at calling skb_clone() 207 * -EPERM when trying to send on a non-CAN interface 208 * -EINVAL when the skb->data does not contain a valid CAN frame 209 */ 210 int can_send(struct sk_buff *skb, int loop) 211 { 212 struct sk_buff *newskb = NULL; 213 struct can_frame *cf = (struct can_frame *)skb->data; 214 int err; 215 216 if (skb->len != sizeof(struct can_frame) || cf->can_dlc > 8) { 217 kfree_skb(skb); 218 return -EINVAL; 219 } 220 221 if (skb->dev->type != ARPHRD_CAN) { 222 kfree_skb(skb); 223 return -EPERM; 224 } 225 226 if (!(skb->dev->flags & IFF_UP)) { 227 kfree_skb(skb); 228 return -ENETDOWN; 229 } 230 231 skb->protocol = htons(ETH_P_CAN); 232 skb_reset_network_header(skb); 233 skb_reset_transport_header(skb); 234 235 if (loop) { 236 /* local loopback of sent CAN frames */ 237 238 /* indication for the CAN driver: do loopback */ 239 skb->pkt_type = PACKET_LOOPBACK; 240 241 /* 242 * The reference to the originating sock may be required 243 * by the receiving socket to check whether the frame is 244 * its own. Example: can_raw sockopt CAN_RAW_RECV_OWN_MSGS 245 * Therefore we have to ensure that skb->sk remains the 246 * reference to the originating sock by restoring skb->sk 247 * after each skb_clone() or skb_orphan() usage. 248 */ 249 250 if (!(skb->dev->flags & IFF_ECHO)) { 251 /* 252 * If the interface is not capable to do loopback 253 * itself, we do it here. 254 */ 255 newskb = skb_clone(skb, GFP_ATOMIC); 256 if (!newskb) { 257 kfree_skb(skb); 258 return -ENOMEM; 259 } 260 261 newskb->sk = skb->sk; 262 newskb->ip_summed = CHECKSUM_UNNECESSARY; 263 newskb->pkt_type = PACKET_BROADCAST; 264 } 265 } else { 266 /* indication for the CAN driver: no loopback required */ 267 skb->pkt_type = PACKET_HOST; 268 } 269 270 /* send to netdevice */ 271 err = dev_queue_xmit(skb); 272 if (err > 0) 273 err = net_xmit_errno(err); 274 275 if (err) { 276 kfree_skb(newskb); 277 return err; 278 } 279 280 if (newskb) 281 netif_rx(newskb); 282 283 /* update statistics */ 284 can_stats.tx_frames++; 285 can_stats.tx_frames_delta++; 286 287 return 0; 288 } 289 EXPORT_SYMBOL(can_send); 290 291 /* 292 * af_can rx path 293 */ 294 295 static struct dev_rcv_lists *find_dev_rcv_lists(struct net_device *dev) 296 { 297 struct dev_rcv_lists *d = NULL; 298 struct hlist_node *n; 299 300 /* 301 * find receive list for this device 302 * 303 * The hlist_for_each_entry*() macros curse through the list 304 * using the pointer variable n and set d to the containing 305 * struct in each list iteration. Therefore, after list 306 * iteration, d is unmodified when the list is empty, and it 307 * points to last list element, when the list is non-empty 308 * but no match in the loop body is found. I.e. d is *not* 309 * NULL when no match is found. We can, however, use the 310 * cursor variable n to decide if a match was found. 311 */ 312 313 hlist_for_each_entry_rcu(d, n, &can_rx_dev_list, list) { 314 if (d->dev == dev) 315 break; 316 } 317 318 return n ? d : NULL; 319 } 320 321 /** 322 * find_rcv_list - determine optimal filterlist inside device filter struct 323 * @can_id: pointer to CAN identifier of a given can_filter 324 * @mask: pointer to CAN mask of a given can_filter 325 * @d: pointer to the device filter struct 326 * 327 * Description: 328 * Returns the optimal filterlist to reduce the filter handling in the 329 * receive path. This function is called by service functions that need 330 * to register or unregister a can_filter in the filter lists. 331 * 332 * A filter matches in general, when 333 * 334 * <received_can_id> & mask == can_id & mask 335 * 336 * so every bit set in the mask (even CAN_EFF_FLAG, CAN_RTR_FLAG) describe 337 * relevant bits for the filter. 338 * 339 * The filter can be inverted (CAN_INV_FILTER bit set in can_id) or it can 340 * filter for error frames (CAN_ERR_FLAG bit set in mask). For error frames 341 * there is a special filterlist and a special rx path filter handling. 342 * 343 * Return: 344 * Pointer to optimal filterlist for the given can_id/mask pair. 345 * Constistency checked mask. 346 * Reduced can_id to have a preprocessed filter compare value. 347 */ 348 static struct hlist_head *find_rcv_list(canid_t *can_id, canid_t *mask, 349 struct dev_rcv_lists *d) 350 { 351 canid_t inv = *can_id & CAN_INV_FILTER; /* save flag before masking */ 352 353 /* filter for error frames in extra filterlist */ 354 if (*mask & CAN_ERR_FLAG) { 355 /* clear CAN_ERR_FLAG in filter entry */ 356 *mask &= CAN_ERR_MASK; 357 return &d->rx[RX_ERR]; 358 } 359 360 /* with cleared CAN_ERR_FLAG we have a simple mask/value filterpair */ 361 362 #define CAN_EFF_RTR_FLAGS (CAN_EFF_FLAG | CAN_RTR_FLAG) 363 364 /* ensure valid values in can_mask for 'SFF only' frame filtering */ 365 if ((*mask & CAN_EFF_FLAG) && !(*can_id & CAN_EFF_FLAG)) 366 *mask &= (CAN_SFF_MASK | CAN_EFF_RTR_FLAGS); 367 368 /* reduce condition testing at receive time */ 369 *can_id &= *mask; 370 371 /* inverse can_id/can_mask filter */ 372 if (inv) 373 return &d->rx[RX_INV]; 374 375 /* mask == 0 => no condition testing at receive time */ 376 if (!(*mask)) 377 return &d->rx[RX_ALL]; 378 379 /* extra filterlists for the subscription of a single non-RTR can_id */ 380 if (((*mask & CAN_EFF_RTR_FLAGS) == CAN_EFF_RTR_FLAGS) 381 && !(*can_id & CAN_RTR_FLAG)) { 382 383 if (*can_id & CAN_EFF_FLAG) { 384 if (*mask == (CAN_EFF_MASK | CAN_EFF_RTR_FLAGS)) { 385 /* RFC: a future use-case for hash-tables? */ 386 return &d->rx[RX_EFF]; 387 } 388 } else { 389 if (*mask == (CAN_SFF_MASK | CAN_EFF_RTR_FLAGS)) 390 return &d->rx_sff[*can_id]; 391 } 392 } 393 394 /* default: filter via can_id/can_mask */ 395 return &d->rx[RX_FIL]; 396 } 397 398 /** 399 * can_rx_register - subscribe CAN frames from a specific interface 400 * @dev: pointer to netdevice (NULL => subcribe from 'all' CAN devices list) 401 * @can_id: CAN identifier (see description) 402 * @mask: CAN mask (see description) 403 * @func: callback function on filter match 404 * @data: returned parameter for callback function 405 * @ident: string for calling module indentification 406 * 407 * Description: 408 * Invokes the callback function with the received sk_buff and the given 409 * parameter 'data' on a matching receive filter. A filter matches, when 410 * 411 * <received_can_id> & mask == can_id & mask 412 * 413 * The filter can be inverted (CAN_INV_FILTER bit set in can_id) or it can 414 * filter for error frames (CAN_ERR_FLAG bit set in mask). 415 * 416 * The provided pointer to the sk_buff is guaranteed to be valid as long as 417 * the callback function is running. The callback function must *not* free 418 * the given sk_buff while processing it's task. When the given sk_buff is 419 * needed after the end of the callback function it must be cloned inside 420 * the callback function with skb_clone(). 421 * 422 * Return: 423 * 0 on success 424 * -ENOMEM on missing cache mem to create subscription entry 425 * -ENODEV unknown device 426 */ 427 int can_rx_register(struct net_device *dev, canid_t can_id, canid_t mask, 428 void (*func)(struct sk_buff *, void *), void *data, 429 char *ident) 430 { 431 struct receiver *r; 432 struct hlist_head *rl; 433 struct dev_rcv_lists *d; 434 int err = 0; 435 436 /* insert new receiver (dev,canid,mask) -> (func,data) */ 437 438 r = kmem_cache_alloc(rcv_cache, GFP_KERNEL); 439 if (!r) 440 return -ENOMEM; 441 442 spin_lock(&can_rcvlists_lock); 443 444 d = find_dev_rcv_lists(dev); 445 if (d) { 446 rl = find_rcv_list(&can_id, &mask, d); 447 448 r->can_id = can_id; 449 r->mask = mask; 450 r->matches = 0; 451 r->func = func; 452 r->data = data; 453 r->ident = ident; 454 455 hlist_add_head_rcu(&r->list, rl); 456 d->entries++; 457 458 can_pstats.rcv_entries++; 459 if (can_pstats.rcv_entries_max < can_pstats.rcv_entries) 460 can_pstats.rcv_entries_max = can_pstats.rcv_entries; 461 } else { 462 kmem_cache_free(rcv_cache, r); 463 err = -ENODEV; 464 } 465 466 spin_unlock(&can_rcvlists_lock); 467 468 return err; 469 } 470 EXPORT_SYMBOL(can_rx_register); 471 472 /* 473 * can_rx_delete_device - rcu callback for dev_rcv_lists structure removal 474 */ 475 static void can_rx_delete_device(struct rcu_head *rp) 476 { 477 struct dev_rcv_lists *d = container_of(rp, struct dev_rcv_lists, rcu); 478 479 kfree(d); 480 } 481 482 /* 483 * can_rx_delete_receiver - rcu callback for single receiver entry removal 484 */ 485 static void can_rx_delete_receiver(struct rcu_head *rp) 486 { 487 struct receiver *r = container_of(rp, struct receiver, rcu); 488 489 kmem_cache_free(rcv_cache, r); 490 } 491 492 /** 493 * can_rx_unregister - unsubscribe CAN frames from a specific interface 494 * @dev: pointer to netdevice (NULL => unsubcribe from 'all' CAN devices list) 495 * @can_id: CAN identifier 496 * @mask: CAN mask 497 * @func: callback function on filter match 498 * @data: returned parameter for callback function 499 * 500 * Description: 501 * Removes subscription entry depending on given (subscription) values. 502 */ 503 void can_rx_unregister(struct net_device *dev, canid_t can_id, canid_t mask, 504 void (*func)(struct sk_buff *, void *), void *data) 505 { 506 struct receiver *r = NULL; 507 struct hlist_head *rl; 508 struct hlist_node *next; 509 struct dev_rcv_lists *d; 510 511 spin_lock(&can_rcvlists_lock); 512 513 d = find_dev_rcv_lists(dev); 514 if (!d) { 515 printk(KERN_ERR "BUG: receive list not found for " 516 "dev %s, id %03X, mask %03X\n", 517 DNAME(dev), can_id, mask); 518 goto out; 519 } 520 521 rl = find_rcv_list(&can_id, &mask, d); 522 523 /* 524 * Search the receiver list for the item to delete. This should 525 * exist, since no receiver may be unregistered that hasn't 526 * been registered before. 527 */ 528 529 hlist_for_each_entry_rcu(r, next, rl, list) { 530 if (r->can_id == can_id && r->mask == mask 531 && r->func == func && r->data == data) 532 break; 533 } 534 535 /* 536 * Check for bugs in CAN protocol implementations: 537 * If no matching list item was found, the list cursor variable next 538 * will be NULL, while r will point to the last item of the list. 539 */ 540 541 if (!next) { 542 printk(KERN_ERR "BUG: receive list entry not found for " 543 "dev %s, id %03X, mask %03X\n", 544 DNAME(dev), can_id, mask); 545 r = NULL; 546 d = NULL; 547 goto out; 548 } 549 550 hlist_del_rcu(&r->list); 551 d->entries--; 552 553 if (can_pstats.rcv_entries > 0) 554 can_pstats.rcv_entries--; 555 556 /* remove device structure requested by NETDEV_UNREGISTER */ 557 if (d->remove_on_zero_entries && !d->entries) 558 hlist_del_rcu(&d->list); 559 else 560 d = NULL; 561 562 out: 563 spin_unlock(&can_rcvlists_lock); 564 565 /* schedule the receiver item for deletion */ 566 if (r) 567 call_rcu(&r->rcu, can_rx_delete_receiver); 568 569 /* schedule the device structure for deletion */ 570 if (d) 571 call_rcu(&d->rcu, can_rx_delete_device); 572 } 573 EXPORT_SYMBOL(can_rx_unregister); 574 575 static inline void deliver(struct sk_buff *skb, struct receiver *r) 576 { 577 r->func(skb, r->data); 578 r->matches++; 579 } 580 581 static int can_rcv_filter(struct dev_rcv_lists *d, struct sk_buff *skb) 582 { 583 struct receiver *r; 584 struct hlist_node *n; 585 int matches = 0; 586 struct can_frame *cf = (struct can_frame *)skb->data; 587 canid_t can_id = cf->can_id; 588 589 if (d->entries == 0) 590 return 0; 591 592 if (can_id & CAN_ERR_FLAG) { 593 /* check for error frame entries only */ 594 hlist_for_each_entry_rcu(r, n, &d->rx[RX_ERR], list) { 595 if (can_id & r->mask) { 596 deliver(skb, r); 597 matches++; 598 } 599 } 600 return matches; 601 } 602 603 /* check for unfiltered entries */ 604 hlist_for_each_entry_rcu(r, n, &d->rx[RX_ALL], list) { 605 deliver(skb, r); 606 matches++; 607 } 608 609 /* check for can_id/mask entries */ 610 hlist_for_each_entry_rcu(r, n, &d->rx[RX_FIL], list) { 611 if ((can_id & r->mask) == r->can_id) { 612 deliver(skb, r); 613 matches++; 614 } 615 } 616 617 /* check for inverted can_id/mask entries */ 618 hlist_for_each_entry_rcu(r, n, &d->rx[RX_INV], list) { 619 if ((can_id & r->mask) != r->can_id) { 620 deliver(skb, r); 621 matches++; 622 } 623 } 624 625 /* check filterlists for single non-RTR can_ids */ 626 if (can_id & CAN_RTR_FLAG) 627 return matches; 628 629 if (can_id & CAN_EFF_FLAG) { 630 hlist_for_each_entry_rcu(r, n, &d->rx[RX_EFF], list) { 631 if (r->can_id == can_id) { 632 deliver(skb, r); 633 matches++; 634 } 635 } 636 } else { 637 can_id &= CAN_SFF_MASK; 638 hlist_for_each_entry_rcu(r, n, &d->rx_sff[can_id], list) { 639 deliver(skb, r); 640 matches++; 641 } 642 } 643 644 return matches; 645 } 646 647 static int can_rcv(struct sk_buff *skb, struct net_device *dev, 648 struct packet_type *pt, struct net_device *orig_dev) 649 { 650 struct dev_rcv_lists *d; 651 struct can_frame *cf = (struct can_frame *)skb->data; 652 int matches; 653 654 if (dev->type != ARPHRD_CAN || !net_eq(dev_net(dev), &init_net)) { 655 kfree_skb(skb); 656 return 0; 657 } 658 659 BUG_ON(skb->len != sizeof(struct can_frame) || cf->can_dlc > 8); 660 661 /* update statistics */ 662 can_stats.rx_frames++; 663 can_stats.rx_frames_delta++; 664 665 rcu_read_lock(); 666 667 /* deliver the packet to sockets listening on all devices */ 668 matches = can_rcv_filter(&can_rx_alldev_list, skb); 669 670 /* find receive list for this device */ 671 d = find_dev_rcv_lists(dev); 672 if (d) 673 matches += can_rcv_filter(d, skb); 674 675 rcu_read_unlock(); 676 677 /* free the skbuff allocated by the netdevice driver */ 678 kfree_skb(skb); 679 680 if (matches > 0) { 681 can_stats.matches++; 682 can_stats.matches_delta++; 683 } 684 685 return 0; 686 } 687 688 /* 689 * af_can protocol functions 690 */ 691 692 /** 693 * can_proto_register - register CAN transport protocol 694 * @cp: pointer to CAN protocol structure 695 * 696 * Return: 697 * 0 on success 698 * -EINVAL invalid (out of range) protocol number 699 * -EBUSY protocol already in use 700 * -ENOBUF if proto_register() fails 701 */ 702 int can_proto_register(struct can_proto *cp) 703 { 704 int proto = cp->protocol; 705 int err = 0; 706 707 if (proto < 0 || proto >= CAN_NPROTO) { 708 printk(KERN_ERR "can: protocol number %d out of range\n", 709 proto); 710 return -EINVAL; 711 } 712 713 err = proto_register(cp->prot, 0); 714 if (err < 0) 715 return err; 716 717 spin_lock(&proto_tab_lock); 718 if (proto_tab[proto]) { 719 printk(KERN_ERR "can: protocol %d already registered\n", 720 proto); 721 err = -EBUSY; 722 } else { 723 proto_tab[proto] = cp; 724 725 /* use generic ioctl function if not defined by module */ 726 if (!cp->ops->ioctl) 727 cp->ops->ioctl = can_ioctl; 728 } 729 spin_unlock(&proto_tab_lock); 730 731 if (err < 0) 732 proto_unregister(cp->prot); 733 734 return err; 735 } 736 EXPORT_SYMBOL(can_proto_register); 737 738 /** 739 * can_proto_unregister - unregister CAN transport protocol 740 * @cp: pointer to CAN protocol structure 741 */ 742 void can_proto_unregister(struct can_proto *cp) 743 { 744 int proto = cp->protocol; 745 746 spin_lock(&proto_tab_lock); 747 if (!proto_tab[proto]) { 748 printk(KERN_ERR "BUG: can: protocol %d is not registered\n", 749 proto); 750 } 751 proto_tab[proto] = NULL; 752 spin_unlock(&proto_tab_lock); 753 754 proto_unregister(cp->prot); 755 } 756 EXPORT_SYMBOL(can_proto_unregister); 757 758 /* 759 * af_can notifier to create/remove CAN netdevice specific structs 760 */ 761 static int can_notifier(struct notifier_block *nb, unsigned long msg, 762 void *data) 763 { 764 struct net_device *dev = (struct net_device *)data; 765 struct dev_rcv_lists *d; 766 767 if (!net_eq(dev_net(dev), &init_net)) 768 return NOTIFY_DONE; 769 770 if (dev->type != ARPHRD_CAN) 771 return NOTIFY_DONE; 772 773 switch (msg) { 774 775 case NETDEV_REGISTER: 776 777 /* 778 * create new dev_rcv_lists for this device 779 * 780 * N.B. zeroing the struct is the correct initialization 781 * for the embedded hlist_head structs. 782 * Another list type, e.g. list_head, would require 783 * explicit initialization. 784 */ 785 786 d = kzalloc(sizeof(*d), GFP_KERNEL); 787 if (!d) { 788 printk(KERN_ERR 789 "can: allocation of receive list failed\n"); 790 return NOTIFY_DONE; 791 } 792 d->dev = dev; 793 794 spin_lock(&can_rcvlists_lock); 795 hlist_add_head_rcu(&d->list, &can_rx_dev_list); 796 spin_unlock(&can_rcvlists_lock); 797 798 break; 799 800 case NETDEV_UNREGISTER: 801 spin_lock(&can_rcvlists_lock); 802 803 d = find_dev_rcv_lists(dev); 804 if (d) { 805 if (d->entries) { 806 d->remove_on_zero_entries = 1; 807 d = NULL; 808 } else 809 hlist_del_rcu(&d->list); 810 } else 811 printk(KERN_ERR "can: notifier: receive list not " 812 "found for dev %s\n", dev->name); 813 814 spin_unlock(&can_rcvlists_lock); 815 816 if (d) 817 call_rcu(&d->rcu, can_rx_delete_device); 818 819 break; 820 } 821 822 return NOTIFY_DONE; 823 } 824 825 /* 826 * af_can module init/exit functions 827 */ 828 829 static struct packet_type can_packet __read_mostly = { 830 .type = cpu_to_be16(ETH_P_CAN), 831 .dev = NULL, 832 .func = can_rcv, 833 }; 834 835 static struct net_proto_family can_family_ops __read_mostly = { 836 .family = PF_CAN, 837 .create = can_create, 838 .owner = THIS_MODULE, 839 }; 840 841 /* notifier block for netdevice event */ 842 static struct notifier_block can_netdev_notifier __read_mostly = { 843 .notifier_call = can_notifier, 844 }; 845 846 static __init int can_init(void) 847 { 848 printk(banner); 849 850 rcv_cache = kmem_cache_create("can_receiver", sizeof(struct receiver), 851 0, 0, NULL); 852 if (!rcv_cache) 853 return -ENOMEM; 854 855 /* 856 * Insert can_rx_alldev_list for reception on all devices. 857 * This struct is zero initialized which is correct for the 858 * embedded hlist heads, the dev pointer, and the entries counter. 859 */ 860 861 spin_lock(&can_rcvlists_lock); 862 hlist_add_head_rcu(&can_rx_alldev_list.list, &can_rx_dev_list); 863 spin_unlock(&can_rcvlists_lock); 864 865 if (stats_timer) { 866 /* the statistics are updated every second (timer triggered) */ 867 setup_timer(&can_stattimer, can_stat_update, 0); 868 mod_timer(&can_stattimer, round_jiffies(jiffies + HZ)); 869 } else 870 can_stattimer.function = NULL; 871 872 can_init_proc(); 873 874 /* protocol register */ 875 sock_register(&can_family_ops); 876 register_netdevice_notifier(&can_netdev_notifier); 877 dev_add_pack(&can_packet); 878 879 return 0; 880 } 881 882 static __exit void can_exit(void) 883 { 884 struct dev_rcv_lists *d; 885 struct hlist_node *n, *next; 886 887 if (stats_timer) 888 del_timer(&can_stattimer); 889 890 can_remove_proc(); 891 892 /* protocol unregister */ 893 dev_remove_pack(&can_packet); 894 unregister_netdevice_notifier(&can_netdev_notifier); 895 sock_unregister(PF_CAN); 896 897 /* remove can_rx_dev_list */ 898 spin_lock(&can_rcvlists_lock); 899 hlist_del(&can_rx_alldev_list.list); 900 hlist_for_each_entry_safe(d, n, next, &can_rx_dev_list, list) { 901 hlist_del(&d->list); 902 kfree(d); 903 } 904 spin_unlock(&can_rcvlists_lock); 905 906 kmem_cache_destroy(rcv_cache); 907 } 908 909 module_init(can_init); 910 module_exit(can_exit); 911