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 int kern) 119 { 120 struct sock *sk; 121 struct can_proto *cp; 122 int err = 0; 123 124 sock->state = SS_UNCONNECTED; 125 126 if (protocol < 0 || protocol >= CAN_NPROTO) 127 return -EINVAL; 128 129 if (!net_eq(net, &init_net)) 130 return -EAFNOSUPPORT; 131 132 #ifdef CONFIG_MODULES 133 /* try to load protocol module kernel is modular */ 134 if (!proto_tab[protocol]) { 135 err = request_module("can-proto-%d", protocol); 136 137 /* 138 * In case of error we only print a message but don't 139 * return the error code immediately. Below we will 140 * return -EPROTONOSUPPORT 141 */ 142 if (err && printk_ratelimit()) 143 printk(KERN_ERR "can: request_module " 144 "(can-proto-%d) failed.\n", protocol); 145 } 146 #endif 147 148 spin_lock(&proto_tab_lock); 149 cp = proto_tab[protocol]; 150 if (cp && !try_module_get(cp->prot->owner)) 151 cp = NULL; 152 spin_unlock(&proto_tab_lock); 153 154 /* check for available protocol and correct usage */ 155 156 if (!cp) 157 return -EPROTONOSUPPORT; 158 159 if (cp->type != sock->type) { 160 err = -EPROTONOSUPPORT; 161 goto errout; 162 } 163 164 sock->ops = cp->ops; 165 166 sk = sk_alloc(net, PF_CAN, GFP_KERNEL, cp->prot); 167 if (!sk) { 168 err = -ENOMEM; 169 goto errout; 170 } 171 172 sock_init_data(sock, sk); 173 sk->sk_destruct = can_sock_destruct; 174 175 if (sk->sk_prot->init) 176 err = sk->sk_prot->init(sk); 177 178 if (err) { 179 /* release sk on errors */ 180 sock_orphan(sk); 181 sock_put(sk); 182 } 183 184 errout: 185 module_put(cp->prot->owner); 186 return err; 187 } 188 189 /* 190 * af_can tx path 191 */ 192 193 /** 194 * can_send - transmit a CAN frame (optional with local loopback) 195 * @skb: pointer to socket buffer with CAN frame in data section 196 * @loop: loopback for listeners on local CAN sockets (recommended default!) 197 * 198 * Due to the loopback this routine must not be called from hardirq context. 199 * 200 * Return: 201 * 0 on success 202 * -ENETDOWN when the selected interface is down 203 * -ENOBUFS on full driver queue (see net_xmit_errno()) 204 * -ENOMEM when local loopback failed at calling skb_clone() 205 * -EPERM when trying to send on a non-CAN interface 206 * -EINVAL when the skb->data does not contain a valid CAN frame 207 */ 208 int can_send(struct sk_buff *skb, int loop) 209 { 210 struct sk_buff *newskb = NULL; 211 struct can_frame *cf = (struct can_frame *)skb->data; 212 int err; 213 214 if (skb->len != sizeof(struct can_frame) || cf->can_dlc > 8) { 215 kfree_skb(skb); 216 return -EINVAL; 217 } 218 219 if (skb->dev->type != ARPHRD_CAN) { 220 kfree_skb(skb); 221 return -EPERM; 222 } 223 224 if (!(skb->dev->flags & IFF_UP)) { 225 kfree_skb(skb); 226 return -ENETDOWN; 227 } 228 229 skb->protocol = htons(ETH_P_CAN); 230 skb_reset_network_header(skb); 231 skb_reset_transport_header(skb); 232 233 if (loop) { 234 /* local loopback of sent CAN frames */ 235 236 /* indication for the CAN driver: do loopback */ 237 skb->pkt_type = PACKET_LOOPBACK; 238 239 /* 240 * The reference to the originating sock may be required 241 * by the receiving socket to check whether the frame is 242 * its own. Example: can_raw sockopt CAN_RAW_RECV_OWN_MSGS 243 * Therefore we have to ensure that skb->sk remains the 244 * reference to the originating sock by restoring skb->sk 245 * after each skb_clone() or skb_orphan() usage. 246 */ 247 248 if (!(skb->dev->flags & IFF_ECHO)) { 249 /* 250 * If the interface is not capable to do loopback 251 * itself, we do it here. 252 */ 253 newskb = skb_clone(skb, GFP_ATOMIC); 254 if (!newskb) { 255 kfree_skb(skb); 256 return -ENOMEM; 257 } 258 259 newskb->sk = skb->sk; 260 newskb->ip_summed = CHECKSUM_UNNECESSARY; 261 newskb->pkt_type = PACKET_BROADCAST; 262 } 263 } else { 264 /* indication for the CAN driver: no loopback required */ 265 skb->pkt_type = PACKET_HOST; 266 } 267 268 /* send to netdevice */ 269 err = dev_queue_xmit(skb); 270 if (err > 0) 271 err = net_xmit_errno(err); 272 273 if (err) { 274 kfree_skb(newskb); 275 return err; 276 } 277 278 if (newskb) 279 netif_rx_ni(newskb); 280 281 /* update statistics */ 282 can_stats.tx_frames++; 283 can_stats.tx_frames_delta++; 284 285 return 0; 286 } 287 EXPORT_SYMBOL(can_send); 288 289 /* 290 * af_can rx path 291 */ 292 293 static struct dev_rcv_lists *find_dev_rcv_lists(struct net_device *dev) 294 { 295 struct dev_rcv_lists *d = NULL; 296 struct hlist_node *n; 297 298 /* 299 * find receive list for this device 300 * 301 * The hlist_for_each_entry*() macros curse through the list 302 * using the pointer variable n and set d to the containing 303 * struct in each list iteration. Therefore, after list 304 * iteration, d is unmodified when the list is empty, and it 305 * points to last list element, when the list is non-empty 306 * but no match in the loop body is found. I.e. d is *not* 307 * NULL when no match is found. We can, however, use the 308 * cursor variable n to decide if a match was found. 309 */ 310 311 hlist_for_each_entry_rcu(d, n, &can_rx_dev_list, list) { 312 if (d->dev == dev) 313 break; 314 } 315 316 return n ? d : NULL; 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 r = kmem_cache_alloc(rcv_cache, GFP_KERNEL); 437 if (!r) 438 return -ENOMEM; 439 440 spin_lock(&can_rcvlists_lock); 441 442 d = find_dev_rcv_lists(dev); 443 if (d) { 444 rl = find_rcv_list(&can_id, &mask, d); 445 446 r->can_id = can_id; 447 r->mask = mask; 448 r->matches = 0; 449 r->func = func; 450 r->data = data; 451 r->ident = ident; 452 453 hlist_add_head_rcu(&r->list, rl); 454 d->entries++; 455 456 can_pstats.rcv_entries++; 457 if (can_pstats.rcv_entries_max < can_pstats.rcv_entries) 458 can_pstats.rcv_entries_max = can_pstats.rcv_entries; 459 } else { 460 kmem_cache_free(rcv_cache, r); 461 err = -ENODEV; 462 } 463 464 spin_unlock(&can_rcvlists_lock); 465 466 return err; 467 } 468 EXPORT_SYMBOL(can_rx_register); 469 470 /* 471 * can_rx_delete_device - rcu callback for dev_rcv_lists structure removal 472 */ 473 static void can_rx_delete_device(struct rcu_head *rp) 474 { 475 struct dev_rcv_lists *d = container_of(rp, struct dev_rcv_lists, rcu); 476 477 kfree(d); 478 } 479 480 /* 481 * can_rx_delete_receiver - rcu callback for single receiver entry removal 482 */ 483 static void can_rx_delete_receiver(struct rcu_head *rp) 484 { 485 struct receiver *r = container_of(rp, struct receiver, rcu); 486 487 kmem_cache_free(rcv_cache, r); 488 } 489 490 /** 491 * can_rx_unregister - unsubscribe CAN frames from a specific interface 492 * @dev: pointer to netdevice (NULL => unsubcribe from 'all' CAN devices list) 493 * @can_id: CAN identifier 494 * @mask: CAN mask 495 * @func: callback function on filter match 496 * @data: returned parameter for callback function 497 * 498 * Description: 499 * Removes subscription entry depending on given (subscription) values. 500 */ 501 void can_rx_unregister(struct net_device *dev, canid_t can_id, canid_t mask, 502 void (*func)(struct sk_buff *, void *), void *data) 503 { 504 struct receiver *r = NULL; 505 struct hlist_head *rl; 506 struct hlist_node *next; 507 struct dev_rcv_lists *d; 508 509 spin_lock(&can_rcvlists_lock); 510 511 d = find_dev_rcv_lists(dev); 512 if (!d) { 513 printk(KERN_ERR "BUG: receive list not found for " 514 "dev %s, id %03X, mask %03X\n", 515 DNAME(dev), can_id, mask); 516 goto out; 517 } 518 519 rl = find_rcv_list(&can_id, &mask, d); 520 521 /* 522 * Search the receiver list for the item to delete. This should 523 * exist, since no receiver may be unregistered that hasn't 524 * been registered before. 525 */ 526 527 hlist_for_each_entry_rcu(r, next, rl, list) { 528 if (r->can_id == can_id && r->mask == mask && 529 r->func == func && r->data == data) 530 break; 531 } 532 533 /* 534 * Check for bugs in CAN protocol implementations: 535 * If no matching list item was found, the list cursor variable next 536 * will be NULL, while r will point to the last item of the list. 537 */ 538 539 if (!next) { 540 printk(KERN_ERR "BUG: receive list entry not found for " 541 "dev %s, id %03X, mask %03X\n", 542 DNAME(dev), can_id, mask); 543 r = NULL; 544 d = NULL; 545 goto out; 546 } 547 548 hlist_del_rcu(&r->list); 549 d->entries--; 550 551 if (can_pstats.rcv_entries > 0) 552 can_pstats.rcv_entries--; 553 554 /* remove device structure requested by NETDEV_UNREGISTER */ 555 if (d->remove_on_zero_entries && !d->entries) 556 hlist_del_rcu(&d->list); 557 else 558 d = NULL; 559 560 out: 561 spin_unlock(&can_rcvlists_lock); 562 563 /* schedule the receiver item for deletion */ 564 if (r) 565 call_rcu(&r->rcu, can_rx_delete_receiver); 566 567 /* schedule the device structure for deletion */ 568 if (d) 569 call_rcu(&d->rcu, can_rx_delete_device); 570 } 571 EXPORT_SYMBOL(can_rx_unregister); 572 573 static inline void deliver(struct sk_buff *skb, struct receiver *r) 574 { 575 r->func(skb, r->data); 576 r->matches++; 577 } 578 579 static int can_rcv_filter(struct dev_rcv_lists *d, struct sk_buff *skb) 580 { 581 struct receiver *r; 582 struct hlist_node *n; 583 int matches = 0; 584 struct can_frame *cf = (struct can_frame *)skb->data; 585 canid_t can_id = cf->can_id; 586 587 if (d->entries == 0) 588 return 0; 589 590 if (can_id & CAN_ERR_FLAG) { 591 /* check for error frame entries only */ 592 hlist_for_each_entry_rcu(r, n, &d->rx[RX_ERR], list) { 593 if (can_id & r->mask) { 594 deliver(skb, r); 595 matches++; 596 } 597 } 598 return matches; 599 } 600 601 /* check for unfiltered entries */ 602 hlist_for_each_entry_rcu(r, n, &d->rx[RX_ALL], list) { 603 deliver(skb, r); 604 matches++; 605 } 606 607 /* check for can_id/mask entries */ 608 hlist_for_each_entry_rcu(r, n, &d->rx[RX_FIL], list) { 609 if ((can_id & r->mask) == r->can_id) { 610 deliver(skb, r); 611 matches++; 612 } 613 } 614 615 /* check for inverted can_id/mask entries */ 616 hlist_for_each_entry_rcu(r, n, &d->rx[RX_INV], list) { 617 if ((can_id & r->mask) != r->can_id) { 618 deliver(skb, r); 619 matches++; 620 } 621 } 622 623 /* check filterlists for single non-RTR can_ids */ 624 if (can_id & CAN_RTR_FLAG) 625 return matches; 626 627 if (can_id & CAN_EFF_FLAG) { 628 hlist_for_each_entry_rcu(r, n, &d->rx[RX_EFF], list) { 629 if (r->can_id == can_id) { 630 deliver(skb, r); 631 matches++; 632 } 633 } 634 } else { 635 can_id &= CAN_SFF_MASK; 636 hlist_for_each_entry_rcu(r, n, &d->rx_sff[can_id], list) { 637 deliver(skb, r); 638 matches++; 639 } 640 } 641 642 return matches; 643 } 644 645 static int can_rcv(struct sk_buff *skb, struct net_device *dev, 646 struct packet_type *pt, struct net_device *orig_dev) 647 { 648 struct dev_rcv_lists *d; 649 struct can_frame *cf = (struct can_frame *)skb->data; 650 int matches; 651 652 if (!net_eq(dev_net(dev), &init_net)) 653 goto drop; 654 655 if (WARN_ONCE(dev->type != ARPHRD_CAN || 656 skb->len != sizeof(struct can_frame) || 657 cf->can_dlc > 8, 658 "PF_CAN: dropped non conform skbuf: " 659 "dev type %d, len %d, can_dlc %d\n", 660 dev->type, skb->len, cf->can_dlc)) 661 goto drop; 662 663 /* update statistics */ 664 can_stats.rx_frames++; 665 can_stats.rx_frames_delta++; 666 667 rcu_read_lock(); 668 669 /* deliver the packet to sockets listening on all devices */ 670 matches = can_rcv_filter(&can_rx_alldev_list, skb); 671 672 /* find receive list for this device */ 673 d = find_dev_rcv_lists(dev); 674 if (d) 675 matches += can_rcv_filter(d, skb); 676 677 rcu_read_unlock(); 678 679 /* consume the skbuff allocated by the netdevice driver */ 680 consume_skb(skb); 681 682 if (matches > 0) { 683 can_stats.matches++; 684 can_stats.matches_delta++; 685 } 686 687 return NET_RX_SUCCESS; 688 689 drop: 690 kfree_skb(skb); 691 return NET_RX_DROP; 692 } 693 694 /* 695 * af_can protocol functions 696 */ 697 698 /** 699 * can_proto_register - register CAN transport protocol 700 * @cp: pointer to CAN protocol structure 701 * 702 * Return: 703 * 0 on success 704 * -EINVAL invalid (out of range) protocol number 705 * -EBUSY protocol already in use 706 * -ENOBUF if proto_register() fails 707 */ 708 int can_proto_register(struct can_proto *cp) 709 { 710 int proto = cp->protocol; 711 int err = 0; 712 713 if (proto < 0 || proto >= CAN_NPROTO) { 714 printk(KERN_ERR "can: protocol number %d out of range\n", 715 proto); 716 return -EINVAL; 717 } 718 719 err = proto_register(cp->prot, 0); 720 if (err < 0) 721 return err; 722 723 spin_lock(&proto_tab_lock); 724 if (proto_tab[proto]) { 725 printk(KERN_ERR "can: protocol %d already registered\n", 726 proto); 727 err = -EBUSY; 728 } else { 729 proto_tab[proto] = cp; 730 731 /* use generic ioctl function if not defined by module */ 732 if (!cp->ops->ioctl) 733 cp->ops->ioctl = can_ioctl; 734 } 735 spin_unlock(&proto_tab_lock); 736 737 if (err < 0) 738 proto_unregister(cp->prot); 739 740 return err; 741 } 742 EXPORT_SYMBOL(can_proto_register); 743 744 /** 745 * can_proto_unregister - unregister CAN transport protocol 746 * @cp: pointer to CAN protocol structure 747 */ 748 void can_proto_unregister(struct can_proto *cp) 749 { 750 int proto = cp->protocol; 751 752 spin_lock(&proto_tab_lock); 753 if (!proto_tab[proto]) { 754 printk(KERN_ERR "BUG: can: protocol %d is not registered\n", 755 proto); 756 } 757 proto_tab[proto] = NULL; 758 spin_unlock(&proto_tab_lock); 759 760 proto_unregister(cp->prot); 761 } 762 EXPORT_SYMBOL(can_proto_unregister); 763 764 /* 765 * af_can notifier to create/remove CAN netdevice specific structs 766 */ 767 static int can_notifier(struct notifier_block *nb, unsigned long msg, 768 void *data) 769 { 770 struct net_device *dev = (struct net_device *)data; 771 struct dev_rcv_lists *d; 772 773 if (!net_eq(dev_net(dev), &init_net)) 774 return NOTIFY_DONE; 775 776 if (dev->type != ARPHRD_CAN) 777 return NOTIFY_DONE; 778 779 switch (msg) { 780 781 case NETDEV_REGISTER: 782 783 /* 784 * create new dev_rcv_lists for this device 785 * 786 * N.B. zeroing the struct is the correct initialization 787 * for the embedded hlist_head structs. 788 * Another list type, e.g. list_head, would require 789 * explicit initialization. 790 */ 791 792 d = kzalloc(sizeof(*d), GFP_KERNEL); 793 if (!d) { 794 printk(KERN_ERR 795 "can: allocation of receive list failed\n"); 796 return NOTIFY_DONE; 797 } 798 d->dev = dev; 799 800 spin_lock(&can_rcvlists_lock); 801 hlist_add_head_rcu(&d->list, &can_rx_dev_list); 802 spin_unlock(&can_rcvlists_lock); 803 804 break; 805 806 case NETDEV_UNREGISTER: 807 spin_lock(&can_rcvlists_lock); 808 809 d = find_dev_rcv_lists(dev); 810 if (d) { 811 if (d->entries) { 812 d->remove_on_zero_entries = 1; 813 d = NULL; 814 } else 815 hlist_del_rcu(&d->list); 816 } else 817 printk(KERN_ERR "can: notifier: receive list not " 818 "found for dev %s\n", dev->name); 819 820 spin_unlock(&can_rcvlists_lock); 821 822 if (d) 823 call_rcu(&d->rcu, can_rx_delete_device); 824 825 break; 826 } 827 828 return NOTIFY_DONE; 829 } 830 831 /* 832 * af_can module init/exit functions 833 */ 834 835 static struct packet_type can_packet __read_mostly = { 836 .type = cpu_to_be16(ETH_P_CAN), 837 .dev = NULL, 838 .func = can_rcv, 839 }; 840 841 static const struct net_proto_family can_family_ops = { 842 .family = PF_CAN, 843 .create = can_create, 844 .owner = THIS_MODULE, 845 }; 846 847 /* notifier block for netdevice event */ 848 static struct notifier_block can_netdev_notifier __read_mostly = { 849 .notifier_call = can_notifier, 850 }; 851 852 static __init int can_init(void) 853 { 854 printk(banner); 855 856 rcv_cache = kmem_cache_create("can_receiver", sizeof(struct receiver), 857 0, 0, NULL); 858 if (!rcv_cache) 859 return -ENOMEM; 860 861 /* 862 * Insert can_rx_alldev_list for reception on all devices. 863 * This struct is zero initialized which is correct for the 864 * embedded hlist heads, the dev pointer, and the entries counter. 865 */ 866 867 spin_lock(&can_rcvlists_lock); 868 hlist_add_head_rcu(&can_rx_alldev_list.list, &can_rx_dev_list); 869 spin_unlock(&can_rcvlists_lock); 870 871 if (stats_timer) { 872 /* the statistics are updated every second (timer triggered) */ 873 setup_timer(&can_stattimer, can_stat_update, 0); 874 mod_timer(&can_stattimer, round_jiffies(jiffies + HZ)); 875 } else 876 can_stattimer.function = NULL; 877 878 can_init_proc(); 879 880 /* protocol register */ 881 sock_register(&can_family_ops); 882 register_netdevice_notifier(&can_netdev_notifier); 883 dev_add_pack(&can_packet); 884 885 return 0; 886 } 887 888 static __exit void can_exit(void) 889 { 890 struct dev_rcv_lists *d; 891 struct hlist_node *n, *next; 892 893 if (stats_timer) 894 del_timer(&can_stattimer); 895 896 can_remove_proc(); 897 898 /* protocol unregister */ 899 dev_remove_pack(&can_packet); 900 unregister_netdevice_notifier(&can_netdev_notifier); 901 sock_unregister(PF_CAN); 902 903 /* remove can_rx_dev_list */ 904 spin_lock(&can_rcvlists_lock); 905 hlist_del(&can_rx_alldev_list.list); 906 hlist_for_each_entry_safe(d, n, next, &can_rx_dev_list, list) { 907 hlist_del(&d->list); 908 kfree(d); 909 } 910 spin_unlock(&can_rcvlists_lock); 911 912 rcu_barrier(); /* Wait for completion of call_rcu()'s */ 913 914 kmem_cache_destroy(rcv_cache); 915 } 916 917 module_init(can_init); 918 module_exit(can_exit); 919