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 if (newskb) 277 kfree_skb(newskb); 278 return err; 279 } 280 281 if (newskb) 282 netif_rx(newskb); 283 284 /* update statistics */ 285 can_stats.tx_frames++; 286 can_stats.tx_frames_delta++; 287 288 return 0; 289 } 290 EXPORT_SYMBOL(can_send); 291 292 /* 293 * af_can rx path 294 */ 295 296 static struct dev_rcv_lists *find_dev_rcv_lists(struct net_device *dev) 297 { 298 struct dev_rcv_lists *d = NULL; 299 struct hlist_node *n; 300 301 /* 302 * find receive list for this device 303 * 304 * The hlist_for_each_entry*() macros curse through the list 305 * using the pointer variable n and set d to the containing 306 * struct in each list iteration. Therefore, after list 307 * iteration, d is unmodified when the list is empty, and it 308 * points to last list element, when the list is non-empty 309 * but no match in the loop body is found. I.e. d is *not* 310 * NULL when no match is found. We can, however, use the 311 * cursor variable n to decide if a match was found. 312 */ 313 314 hlist_for_each_entry_rcu(d, n, &can_rx_dev_list, list) { 315 if (d->dev == dev) 316 break; 317 } 318 319 return n ? d : NULL; 320 } 321 322 /** 323 * find_rcv_list - determine optimal filterlist inside device filter struct 324 * @can_id: pointer to CAN identifier of a given can_filter 325 * @mask: pointer to CAN mask of a given can_filter 326 * @d: pointer to the device filter struct 327 * 328 * Description: 329 * Returns the optimal filterlist to reduce the filter handling in the 330 * receive path. This function is called by service functions that need 331 * to register or unregister a can_filter in the filter lists. 332 * 333 * A filter matches in general, when 334 * 335 * <received_can_id> & mask == can_id & mask 336 * 337 * so every bit set in the mask (even CAN_EFF_FLAG, CAN_RTR_FLAG) describe 338 * relevant bits for the filter. 339 * 340 * The filter can be inverted (CAN_INV_FILTER bit set in can_id) or it can 341 * filter for error frames (CAN_ERR_FLAG bit set in mask). For error frames 342 * there is a special filterlist and a special rx path filter handling. 343 * 344 * Return: 345 * Pointer to optimal filterlist for the given can_id/mask pair. 346 * Constistency checked mask. 347 * Reduced can_id to have a preprocessed filter compare value. 348 */ 349 static struct hlist_head *find_rcv_list(canid_t *can_id, canid_t *mask, 350 struct dev_rcv_lists *d) 351 { 352 canid_t inv = *can_id & CAN_INV_FILTER; /* save flag before masking */ 353 354 /* filter for error frames in extra filterlist */ 355 if (*mask & CAN_ERR_FLAG) { 356 /* clear CAN_ERR_FLAG in filter entry */ 357 *mask &= CAN_ERR_MASK; 358 return &d->rx[RX_ERR]; 359 } 360 361 /* with cleared CAN_ERR_FLAG we have a simple mask/value filterpair */ 362 363 #define CAN_EFF_RTR_FLAGS (CAN_EFF_FLAG | CAN_RTR_FLAG) 364 365 /* ensure valid values in can_mask for 'SFF only' frame filtering */ 366 if ((*mask & CAN_EFF_FLAG) && !(*can_id & CAN_EFF_FLAG)) 367 *mask &= (CAN_SFF_MASK | CAN_EFF_RTR_FLAGS); 368 369 /* reduce condition testing at receive time */ 370 *can_id &= *mask; 371 372 /* inverse can_id/can_mask filter */ 373 if (inv) 374 return &d->rx[RX_INV]; 375 376 /* mask == 0 => no condition testing at receive time */ 377 if (!(*mask)) 378 return &d->rx[RX_ALL]; 379 380 /* extra filterlists for the subscription of a single non-RTR can_id */ 381 if (((*mask & CAN_EFF_RTR_FLAGS) == CAN_EFF_RTR_FLAGS) 382 && !(*can_id & CAN_RTR_FLAG)) { 383 384 if (*can_id & CAN_EFF_FLAG) { 385 if (*mask == (CAN_EFF_MASK | CAN_EFF_RTR_FLAGS)) { 386 /* RFC: a future use-case for hash-tables? */ 387 return &d->rx[RX_EFF]; 388 } 389 } else { 390 if (*mask == (CAN_SFF_MASK | CAN_EFF_RTR_FLAGS)) 391 return &d->rx_sff[*can_id]; 392 } 393 } 394 395 /* default: filter via can_id/can_mask */ 396 return &d->rx[RX_FIL]; 397 } 398 399 /** 400 * can_rx_register - subscribe CAN frames from a specific interface 401 * @dev: pointer to netdevice (NULL => subcribe from 'all' CAN devices list) 402 * @can_id: CAN identifier (see description) 403 * @mask: CAN mask (see description) 404 * @func: callback function on filter match 405 * @data: returned parameter for callback function 406 * @ident: string for calling module indentification 407 * 408 * Description: 409 * Invokes the callback function with the received sk_buff and the given 410 * parameter 'data' on a matching receive filter. A filter matches, when 411 * 412 * <received_can_id> & mask == can_id & mask 413 * 414 * The filter can be inverted (CAN_INV_FILTER bit set in can_id) or it can 415 * filter for error frames (CAN_ERR_FLAG bit set in mask). 416 * 417 * The provided pointer to the sk_buff is guaranteed to be valid as long as 418 * the callback function is running. The callback function must *not* free 419 * the given sk_buff while processing it's task. When the given sk_buff is 420 * needed after the end of the callback function it must be cloned inside 421 * the callback function with skb_clone(). 422 * 423 * Return: 424 * 0 on success 425 * -ENOMEM on missing cache mem to create subscription entry 426 * -ENODEV unknown device 427 */ 428 int can_rx_register(struct net_device *dev, canid_t can_id, canid_t mask, 429 void (*func)(struct sk_buff *, void *), void *data, 430 char *ident) 431 { 432 struct receiver *r; 433 struct hlist_head *rl; 434 struct dev_rcv_lists *d; 435 int err = 0; 436 437 /* insert new receiver (dev,canid,mask) -> (func,data) */ 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_device - rcu callback for dev_rcv_lists structure removal 475 */ 476 static void can_rx_delete_device(struct rcu_head *rp) 477 { 478 struct dev_rcv_lists *d = container_of(rp, struct dev_rcv_lists, rcu); 479 480 kfree(d); 481 } 482 483 /* 484 * can_rx_delete_receiver - rcu callback for single receiver entry removal 485 */ 486 static void can_rx_delete_receiver(struct rcu_head *rp) 487 { 488 struct receiver *r = container_of(rp, struct receiver, rcu); 489 490 kmem_cache_free(rcv_cache, r); 491 } 492 493 /** 494 * can_rx_unregister - unsubscribe CAN frames from a specific interface 495 * @dev: pointer to netdevice (NULL => unsubcribe from 'all' CAN devices list) 496 * @can_id: CAN identifier 497 * @mask: CAN mask 498 * @func: callback function on filter match 499 * @data: returned parameter for callback function 500 * 501 * Description: 502 * Removes subscription entry depending on given (subscription) values. 503 */ 504 void can_rx_unregister(struct net_device *dev, canid_t can_id, canid_t mask, 505 void (*func)(struct sk_buff *, void *), void *data) 506 { 507 struct receiver *r = NULL; 508 struct hlist_head *rl; 509 struct hlist_node *next; 510 struct dev_rcv_lists *d; 511 512 spin_lock(&can_rcvlists_lock); 513 514 d = find_dev_rcv_lists(dev); 515 if (!d) { 516 printk(KERN_ERR "BUG: receive list not found for " 517 "dev %s, id %03X, mask %03X\n", 518 DNAME(dev), can_id, mask); 519 goto out; 520 } 521 522 rl = find_rcv_list(&can_id, &mask, d); 523 524 /* 525 * Search the receiver list for the item to delete. This should 526 * exist, since no receiver may be unregistered that hasn't 527 * been registered before. 528 */ 529 530 hlist_for_each_entry_rcu(r, next, rl, list) { 531 if (r->can_id == can_id && r->mask == mask 532 && r->func == func && r->data == data) 533 break; 534 } 535 536 /* 537 * Check for bugs in CAN protocol implementations: 538 * If no matching list item was found, the list cursor variable next 539 * will be NULL, while r will point to the last item of the list. 540 */ 541 542 if (!next) { 543 printk(KERN_ERR "BUG: receive list entry not found for " 544 "dev %s, id %03X, mask %03X\n", 545 DNAME(dev), can_id, mask); 546 r = NULL; 547 d = NULL; 548 goto out; 549 } 550 551 hlist_del_rcu(&r->list); 552 d->entries--; 553 554 if (can_pstats.rcv_entries > 0) 555 can_pstats.rcv_entries--; 556 557 /* remove device structure requested by NETDEV_UNREGISTER */ 558 if (d->remove_on_zero_entries && !d->entries) 559 hlist_del_rcu(&d->list); 560 else 561 d = NULL; 562 563 out: 564 spin_unlock(&can_rcvlists_lock); 565 566 /* schedule the receiver item for deletion */ 567 if (r) 568 call_rcu(&r->rcu, can_rx_delete_receiver); 569 570 /* schedule the device structure for deletion */ 571 if (d) 572 call_rcu(&d->rcu, can_rx_delete_device); 573 } 574 EXPORT_SYMBOL(can_rx_unregister); 575 576 static inline void deliver(struct sk_buff *skb, struct receiver *r) 577 { 578 r->func(skb, r->data); 579 r->matches++; 580 } 581 582 static int can_rcv_filter(struct dev_rcv_lists *d, struct sk_buff *skb) 583 { 584 struct receiver *r; 585 struct hlist_node *n; 586 int matches = 0; 587 struct can_frame *cf = (struct can_frame *)skb->data; 588 canid_t can_id = cf->can_id; 589 590 if (d->entries == 0) 591 return 0; 592 593 if (can_id & CAN_ERR_FLAG) { 594 /* check for error frame entries only */ 595 hlist_for_each_entry_rcu(r, n, &d->rx[RX_ERR], list) { 596 if (can_id & r->mask) { 597 deliver(skb, r); 598 matches++; 599 } 600 } 601 return matches; 602 } 603 604 /* check for unfiltered entries */ 605 hlist_for_each_entry_rcu(r, n, &d->rx[RX_ALL], list) { 606 deliver(skb, r); 607 matches++; 608 } 609 610 /* check for can_id/mask entries */ 611 hlist_for_each_entry_rcu(r, n, &d->rx[RX_FIL], list) { 612 if ((can_id & r->mask) == r->can_id) { 613 deliver(skb, r); 614 matches++; 615 } 616 } 617 618 /* check for inverted can_id/mask entries */ 619 hlist_for_each_entry_rcu(r, n, &d->rx[RX_INV], list) { 620 if ((can_id & r->mask) != r->can_id) { 621 deliver(skb, r); 622 matches++; 623 } 624 } 625 626 /* check filterlists for single non-RTR can_ids */ 627 if (can_id & CAN_RTR_FLAG) 628 return matches; 629 630 if (can_id & CAN_EFF_FLAG) { 631 hlist_for_each_entry_rcu(r, n, &d->rx[RX_EFF], list) { 632 if (r->can_id == can_id) { 633 deliver(skb, r); 634 matches++; 635 } 636 } 637 } else { 638 can_id &= CAN_SFF_MASK; 639 hlist_for_each_entry_rcu(r, n, &d->rx_sff[can_id], list) { 640 deliver(skb, r); 641 matches++; 642 } 643 } 644 645 return matches; 646 } 647 648 static int can_rcv(struct sk_buff *skb, struct net_device *dev, 649 struct packet_type *pt, struct net_device *orig_dev) 650 { 651 struct dev_rcv_lists *d; 652 struct can_frame *cf = (struct can_frame *)skb->data; 653 int matches; 654 655 if (dev->type != ARPHRD_CAN || !net_eq(dev_net(dev), &init_net)) { 656 kfree_skb(skb); 657 return 0; 658 } 659 660 BUG_ON(skb->len != sizeof(struct can_frame) || cf->can_dlc > 8); 661 662 /* update statistics */ 663 can_stats.rx_frames++; 664 can_stats.rx_frames_delta++; 665 666 rcu_read_lock(); 667 668 /* deliver the packet to sockets listening on all devices */ 669 matches = can_rcv_filter(&can_rx_alldev_list, skb); 670 671 /* find receive list for this device */ 672 d = find_dev_rcv_lists(dev); 673 if (d) 674 matches += can_rcv_filter(d, skb); 675 676 rcu_read_unlock(); 677 678 /* free the skbuff allocated by the netdevice driver */ 679 kfree_skb(skb); 680 681 if (matches > 0) { 682 can_stats.matches++; 683 can_stats.matches_delta++; 684 } 685 686 return 0; 687 } 688 689 /* 690 * af_can protocol functions 691 */ 692 693 /** 694 * can_proto_register - register CAN transport protocol 695 * @cp: pointer to CAN protocol structure 696 * 697 * Return: 698 * 0 on success 699 * -EINVAL invalid (out of range) protocol number 700 * -EBUSY protocol already in use 701 * -ENOBUF if proto_register() fails 702 */ 703 int can_proto_register(struct can_proto *cp) 704 { 705 int proto = cp->protocol; 706 int err = 0; 707 708 if (proto < 0 || proto >= CAN_NPROTO) { 709 printk(KERN_ERR "can: protocol number %d out of range\n", 710 proto); 711 return -EINVAL; 712 } 713 714 err = proto_register(cp->prot, 0); 715 if (err < 0) 716 return err; 717 718 spin_lock(&proto_tab_lock); 719 if (proto_tab[proto]) { 720 printk(KERN_ERR "can: protocol %d already registered\n", 721 proto); 722 err = -EBUSY; 723 } else { 724 proto_tab[proto] = cp; 725 726 /* use generic ioctl function if not defined by module */ 727 if (!cp->ops->ioctl) 728 cp->ops->ioctl = can_ioctl; 729 } 730 spin_unlock(&proto_tab_lock); 731 732 if (err < 0) 733 proto_unregister(cp->prot); 734 735 return err; 736 } 737 EXPORT_SYMBOL(can_proto_register); 738 739 /** 740 * can_proto_unregister - unregister CAN transport protocol 741 * @cp: pointer to CAN protocol structure 742 */ 743 void can_proto_unregister(struct can_proto *cp) 744 { 745 int proto = cp->protocol; 746 747 spin_lock(&proto_tab_lock); 748 if (!proto_tab[proto]) { 749 printk(KERN_ERR "BUG: can: protocol %d is not registered\n", 750 proto); 751 } 752 proto_tab[proto] = NULL; 753 spin_unlock(&proto_tab_lock); 754 755 proto_unregister(cp->prot); 756 } 757 EXPORT_SYMBOL(can_proto_unregister); 758 759 /* 760 * af_can notifier to create/remove CAN netdevice specific structs 761 */ 762 static int can_notifier(struct notifier_block *nb, unsigned long msg, 763 void *data) 764 { 765 struct net_device *dev = (struct net_device *)data; 766 struct dev_rcv_lists *d; 767 768 if (!net_eq(dev_net(dev), &init_net)) 769 return NOTIFY_DONE; 770 771 if (dev->type != ARPHRD_CAN) 772 return NOTIFY_DONE; 773 774 switch (msg) { 775 776 case NETDEV_REGISTER: 777 778 /* 779 * create new dev_rcv_lists for this device 780 * 781 * N.B. zeroing the struct is the correct initialization 782 * for the embedded hlist_head structs. 783 * Another list type, e.g. list_head, would require 784 * explicit initialization. 785 */ 786 787 d = kzalloc(sizeof(*d), GFP_KERNEL); 788 if (!d) { 789 printk(KERN_ERR 790 "can: allocation of receive list failed\n"); 791 return NOTIFY_DONE; 792 } 793 d->dev = dev; 794 795 spin_lock(&can_rcvlists_lock); 796 hlist_add_head_rcu(&d->list, &can_rx_dev_list); 797 spin_unlock(&can_rcvlists_lock); 798 799 break; 800 801 case NETDEV_UNREGISTER: 802 spin_lock(&can_rcvlists_lock); 803 804 d = find_dev_rcv_lists(dev); 805 if (d) { 806 if (d->entries) { 807 d->remove_on_zero_entries = 1; 808 d = NULL; 809 } else 810 hlist_del_rcu(&d->list); 811 } else 812 printk(KERN_ERR "can: notifier: receive list not " 813 "found for dev %s\n", dev->name); 814 815 spin_unlock(&can_rcvlists_lock); 816 817 if (d) 818 call_rcu(&d->rcu, can_rx_delete_device); 819 820 break; 821 } 822 823 return NOTIFY_DONE; 824 } 825 826 /* 827 * af_can module init/exit functions 828 */ 829 830 static struct packet_type can_packet __read_mostly = { 831 .type = __constant_htons(ETH_P_CAN), 832 .dev = NULL, 833 .func = can_rcv, 834 }; 835 836 static struct net_proto_family can_family_ops __read_mostly = { 837 .family = PF_CAN, 838 .create = can_create, 839 .owner = THIS_MODULE, 840 }; 841 842 /* notifier block for netdevice event */ 843 static struct notifier_block can_netdev_notifier __read_mostly = { 844 .notifier_call = can_notifier, 845 }; 846 847 static __init int can_init(void) 848 { 849 printk(banner); 850 851 rcv_cache = kmem_cache_create("can_receiver", sizeof(struct receiver), 852 0, 0, NULL); 853 if (!rcv_cache) 854 return -ENOMEM; 855 856 /* 857 * Insert can_rx_alldev_list for reception on all devices. 858 * This struct is zero initialized which is correct for the 859 * embedded hlist heads, the dev pointer, and the entries counter. 860 */ 861 862 spin_lock(&can_rcvlists_lock); 863 hlist_add_head_rcu(&can_rx_alldev_list.list, &can_rx_dev_list); 864 spin_unlock(&can_rcvlists_lock); 865 866 if (stats_timer) { 867 /* the statistics are updated every second (timer triggered) */ 868 setup_timer(&can_stattimer, can_stat_update, 0); 869 mod_timer(&can_stattimer, round_jiffies(jiffies + HZ)); 870 } else 871 can_stattimer.function = NULL; 872 873 can_init_proc(); 874 875 /* protocol register */ 876 sock_register(&can_family_ops); 877 register_netdevice_notifier(&can_netdev_notifier); 878 dev_add_pack(&can_packet); 879 880 return 0; 881 } 882 883 static __exit void can_exit(void) 884 { 885 struct dev_rcv_lists *d; 886 struct hlist_node *n, *next; 887 888 if (stats_timer) 889 del_timer(&can_stattimer); 890 891 can_remove_proc(); 892 893 /* protocol unregister */ 894 dev_remove_pack(&can_packet); 895 unregister_netdevice_notifier(&can_netdev_notifier); 896 sock_unregister(PF_CAN); 897 898 /* remove can_rx_dev_list */ 899 spin_lock(&can_rcvlists_lock); 900 hlist_del(&can_rx_alldev_list.list); 901 hlist_for_each_entry_safe(d, n, next, &can_rx_dev_list, list) { 902 hlist_del(&d->list); 903 kfree(d); 904 } 905 spin_unlock(&can_rcvlists_lock); 906 907 kmem_cache_destroy(rcv_cache); 908 } 909 910 module_init(can_init); 911 module_exit(can_exit); 912