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 static struct hlist_head *find_rcv_list(canid_t *can_id, canid_t *mask, 323 struct dev_rcv_lists *d) 324 { 325 canid_t inv = *can_id & CAN_INV_FILTER; /* save flag before masking */ 326 327 /* filter error frames */ 328 if (*mask & CAN_ERR_FLAG) { 329 /* clear CAN_ERR_FLAG in list entry */ 330 *mask &= CAN_ERR_MASK; 331 return &d->rx[RX_ERR]; 332 } 333 334 /* ensure valid values in can_mask */ 335 if (*mask & CAN_EFF_FLAG) 336 *mask &= (CAN_EFF_MASK | CAN_EFF_FLAG | CAN_RTR_FLAG); 337 else 338 *mask &= (CAN_SFF_MASK | CAN_RTR_FLAG); 339 340 /* reduce condition testing at receive time */ 341 *can_id &= *mask; 342 343 /* inverse can_id/can_mask filter */ 344 if (inv) 345 return &d->rx[RX_INV]; 346 347 /* mask == 0 => no condition testing at receive time */ 348 if (!(*mask)) 349 return &d->rx[RX_ALL]; 350 351 /* use extra filterset for the subscription of exactly *ONE* can_id */ 352 if (*can_id & CAN_EFF_FLAG) { 353 if (*mask == (CAN_EFF_MASK | CAN_EFF_FLAG)) { 354 /* RFC: a use-case for hash-tables in the future? */ 355 return &d->rx[RX_EFF]; 356 } 357 } else { 358 if (*mask == CAN_SFF_MASK) 359 return &d->rx_sff[*can_id]; 360 } 361 362 /* default: filter via can_id/can_mask */ 363 return &d->rx[RX_FIL]; 364 } 365 366 /** 367 * can_rx_register - subscribe CAN frames from a specific interface 368 * @dev: pointer to netdevice (NULL => subcribe from 'all' CAN devices list) 369 * @can_id: CAN identifier (see description) 370 * @mask: CAN mask (see description) 371 * @func: callback function on filter match 372 * @data: returned parameter for callback function 373 * @ident: string for calling module indentification 374 * 375 * Description: 376 * Invokes the callback function with the received sk_buff and the given 377 * parameter 'data' on a matching receive filter. A filter matches, when 378 * 379 * <received_can_id> & mask == can_id & mask 380 * 381 * The filter can be inverted (CAN_INV_FILTER bit set in can_id) or it can 382 * filter for error frames (CAN_ERR_FLAG bit set in mask). 383 * 384 * Return: 385 * 0 on success 386 * -ENOMEM on missing cache mem to create subscription entry 387 * -ENODEV unknown device 388 */ 389 int can_rx_register(struct net_device *dev, canid_t can_id, canid_t mask, 390 void (*func)(struct sk_buff *, void *), void *data, 391 char *ident) 392 { 393 struct receiver *r; 394 struct hlist_head *rl; 395 struct dev_rcv_lists *d; 396 int err = 0; 397 398 /* insert new receiver (dev,canid,mask) -> (func,data) */ 399 400 r = kmem_cache_alloc(rcv_cache, GFP_KERNEL); 401 if (!r) 402 return -ENOMEM; 403 404 spin_lock(&can_rcvlists_lock); 405 406 d = find_dev_rcv_lists(dev); 407 if (d) { 408 rl = find_rcv_list(&can_id, &mask, d); 409 410 r->can_id = can_id; 411 r->mask = mask; 412 r->matches = 0; 413 r->func = func; 414 r->data = data; 415 r->ident = ident; 416 417 hlist_add_head_rcu(&r->list, rl); 418 d->entries++; 419 420 can_pstats.rcv_entries++; 421 if (can_pstats.rcv_entries_max < can_pstats.rcv_entries) 422 can_pstats.rcv_entries_max = can_pstats.rcv_entries; 423 } else { 424 kmem_cache_free(rcv_cache, r); 425 err = -ENODEV; 426 } 427 428 spin_unlock(&can_rcvlists_lock); 429 430 return err; 431 } 432 EXPORT_SYMBOL(can_rx_register); 433 434 /* 435 * can_rx_delete_device - rcu callback for dev_rcv_lists structure removal 436 */ 437 static void can_rx_delete_device(struct rcu_head *rp) 438 { 439 struct dev_rcv_lists *d = container_of(rp, struct dev_rcv_lists, rcu); 440 441 kfree(d); 442 } 443 444 /* 445 * can_rx_delete_receiver - rcu callback for single receiver entry removal 446 */ 447 static void can_rx_delete_receiver(struct rcu_head *rp) 448 { 449 struct receiver *r = container_of(rp, struct receiver, rcu); 450 451 kmem_cache_free(rcv_cache, r); 452 } 453 454 /** 455 * can_rx_unregister - unsubscribe CAN frames from a specific interface 456 * @dev: pointer to netdevice (NULL => unsubcribe from 'all' CAN devices list) 457 * @can_id: CAN identifier 458 * @mask: CAN mask 459 * @func: callback function on filter match 460 * @data: returned parameter for callback function 461 * 462 * Description: 463 * Removes subscription entry depending on given (subscription) values. 464 */ 465 void can_rx_unregister(struct net_device *dev, canid_t can_id, canid_t mask, 466 void (*func)(struct sk_buff *, void *), void *data) 467 { 468 struct receiver *r = NULL; 469 struct hlist_head *rl; 470 struct hlist_node *next; 471 struct dev_rcv_lists *d; 472 473 spin_lock(&can_rcvlists_lock); 474 475 d = find_dev_rcv_lists(dev); 476 if (!d) { 477 printk(KERN_ERR "BUG: receive list not found for " 478 "dev %s, id %03X, mask %03X\n", 479 DNAME(dev), can_id, mask); 480 goto out; 481 } 482 483 rl = find_rcv_list(&can_id, &mask, d); 484 485 /* 486 * Search the receiver list for the item to delete. This should 487 * exist, since no receiver may be unregistered that hasn't 488 * been registered before. 489 */ 490 491 hlist_for_each_entry_rcu(r, next, rl, list) { 492 if (r->can_id == can_id && r->mask == mask 493 && r->func == func && r->data == data) 494 break; 495 } 496 497 /* 498 * Check for bugs in CAN protocol implementations: 499 * If no matching list item was found, the list cursor variable next 500 * will be NULL, while r will point to the last item of the list. 501 */ 502 503 if (!next) { 504 printk(KERN_ERR "BUG: receive list entry not found for " 505 "dev %s, id %03X, mask %03X\n", 506 DNAME(dev), can_id, mask); 507 r = NULL; 508 d = NULL; 509 goto out; 510 } 511 512 hlist_del_rcu(&r->list); 513 d->entries--; 514 515 if (can_pstats.rcv_entries > 0) 516 can_pstats.rcv_entries--; 517 518 /* remove device structure requested by NETDEV_UNREGISTER */ 519 if (d->remove_on_zero_entries && !d->entries) 520 hlist_del_rcu(&d->list); 521 else 522 d = NULL; 523 524 out: 525 spin_unlock(&can_rcvlists_lock); 526 527 /* schedule the receiver item for deletion */ 528 if (r) 529 call_rcu(&r->rcu, can_rx_delete_receiver); 530 531 /* schedule the device structure for deletion */ 532 if (d) 533 call_rcu(&d->rcu, can_rx_delete_device); 534 } 535 EXPORT_SYMBOL(can_rx_unregister); 536 537 static inline void deliver(struct sk_buff *skb, struct receiver *r) 538 { 539 struct sk_buff *clone = skb_clone(skb, GFP_ATOMIC); 540 541 if (clone) { 542 clone->sk = skb->sk; 543 r->func(clone, r->data); 544 r->matches++; 545 } 546 } 547 548 static int can_rcv_filter(struct dev_rcv_lists *d, struct sk_buff *skb) 549 { 550 struct receiver *r; 551 struct hlist_node *n; 552 int matches = 0; 553 struct can_frame *cf = (struct can_frame *)skb->data; 554 canid_t can_id = cf->can_id; 555 556 if (d->entries == 0) 557 return 0; 558 559 if (can_id & CAN_ERR_FLAG) { 560 /* check for error frame entries only */ 561 hlist_for_each_entry_rcu(r, n, &d->rx[RX_ERR], list) { 562 if (can_id & r->mask) { 563 deliver(skb, r); 564 matches++; 565 } 566 } 567 return matches; 568 } 569 570 /* check for unfiltered entries */ 571 hlist_for_each_entry_rcu(r, n, &d->rx[RX_ALL], list) { 572 deliver(skb, r); 573 matches++; 574 } 575 576 /* check for can_id/mask entries */ 577 hlist_for_each_entry_rcu(r, n, &d->rx[RX_FIL], list) { 578 if ((can_id & r->mask) == r->can_id) { 579 deliver(skb, r); 580 matches++; 581 } 582 } 583 584 /* check for inverted can_id/mask entries */ 585 hlist_for_each_entry_rcu(r, n, &d->rx[RX_INV], list) { 586 if ((can_id & r->mask) != r->can_id) { 587 deliver(skb, r); 588 matches++; 589 } 590 } 591 592 /* check CAN_ID specific entries */ 593 if (can_id & CAN_EFF_FLAG) { 594 hlist_for_each_entry_rcu(r, n, &d->rx[RX_EFF], list) { 595 if (r->can_id == can_id) { 596 deliver(skb, r); 597 matches++; 598 } 599 } 600 } else { 601 can_id &= CAN_SFF_MASK; 602 hlist_for_each_entry_rcu(r, n, &d->rx_sff[can_id], list) { 603 deliver(skb, r); 604 matches++; 605 } 606 } 607 608 return matches; 609 } 610 611 static int can_rcv(struct sk_buff *skb, struct net_device *dev, 612 struct packet_type *pt, struct net_device *orig_dev) 613 { 614 struct dev_rcv_lists *d; 615 struct can_frame *cf = (struct can_frame *)skb->data; 616 int matches; 617 618 if (dev->type != ARPHRD_CAN || !net_eq(dev_net(dev), &init_net)) { 619 kfree_skb(skb); 620 return 0; 621 } 622 623 BUG_ON(skb->len != sizeof(struct can_frame) || cf->can_dlc > 8); 624 625 /* update statistics */ 626 can_stats.rx_frames++; 627 can_stats.rx_frames_delta++; 628 629 rcu_read_lock(); 630 631 /* deliver the packet to sockets listening on all devices */ 632 matches = can_rcv_filter(&can_rx_alldev_list, skb); 633 634 /* find receive list for this device */ 635 d = find_dev_rcv_lists(dev); 636 if (d) 637 matches += can_rcv_filter(d, skb); 638 639 rcu_read_unlock(); 640 641 /* free the skbuff allocated by the netdevice driver */ 642 kfree_skb(skb); 643 644 if (matches > 0) { 645 can_stats.matches++; 646 can_stats.matches_delta++; 647 } 648 649 return 0; 650 } 651 652 /* 653 * af_can protocol functions 654 */ 655 656 /** 657 * can_proto_register - register CAN transport protocol 658 * @cp: pointer to CAN protocol structure 659 * 660 * Return: 661 * 0 on success 662 * -EINVAL invalid (out of range) protocol number 663 * -EBUSY protocol already in use 664 * -ENOBUF if proto_register() fails 665 */ 666 int can_proto_register(struct can_proto *cp) 667 { 668 int proto = cp->protocol; 669 int err = 0; 670 671 if (proto < 0 || proto >= CAN_NPROTO) { 672 printk(KERN_ERR "can: protocol number %d out of range\n", 673 proto); 674 return -EINVAL; 675 } 676 677 err = proto_register(cp->prot, 0); 678 if (err < 0) 679 return err; 680 681 spin_lock(&proto_tab_lock); 682 if (proto_tab[proto]) { 683 printk(KERN_ERR "can: protocol %d already registered\n", 684 proto); 685 err = -EBUSY; 686 } else { 687 proto_tab[proto] = cp; 688 689 /* use generic ioctl function if not defined by module */ 690 if (!cp->ops->ioctl) 691 cp->ops->ioctl = can_ioctl; 692 } 693 spin_unlock(&proto_tab_lock); 694 695 if (err < 0) 696 proto_unregister(cp->prot); 697 698 return err; 699 } 700 EXPORT_SYMBOL(can_proto_register); 701 702 /** 703 * can_proto_unregister - unregister CAN transport protocol 704 * @cp: pointer to CAN protocol structure 705 */ 706 void can_proto_unregister(struct can_proto *cp) 707 { 708 int proto = cp->protocol; 709 710 spin_lock(&proto_tab_lock); 711 if (!proto_tab[proto]) { 712 printk(KERN_ERR "BUG: can: protocol %d is not registered\n", 713 proto); 714 } 715 proto_tab[proto] = NULL; 716 spin_unlock(&proto_tab_lock); 717 718 proto_unregister(cp->prot); 719 } 720 EXPORT_SYMBOL(can_proto_unregister); 721 722 /* 723 * af_can notifier to create/remove CAN netdevice specific structs 724 */ 725 static int can_notifier(struct notifier_block *nb, unsigned long msg, 726 void *data) 727 { 728 struct net_device *dev = (struct net_device *)data; 729 struct dev_rcv_lists *d; 730 731 if (!net_eq(dev_net(dev), &init_net)) 732 return NOTIFY_DONE; 733 734 if (dev->type != ARPHRD_CAN) 735 return NOTIFY_DONE; 736 737 switch (msg) { 738 739 case NETDEV_REGISTER: 740 741 /* 742 * create new dev_rcv_lists for this device 743 * 744 * N.B. zeroing the struct is the correct initialization 745 * for the embedded hlist_head structs. 746 * Another list type, e.g. list_head, would require 747 * explicit initialization. 748 */ 749 750 d = kzalloc(sizeof(*d), GFP_KERNEL); 751 if (!d) { 752 printk(KERN_ERR 753 "can: allocation of receive list failed\n"); 754 return NOTIFY_DONE; 755 } 756 d->dev = dev; 757 758 spin_lock(&can_rcvlists_lock); 759 hlist_add_head_rcu(&d->list, &can_rx_dev_list); 760 spin_unlock(&can_rcvlists_lock); 761 762 break; 763 764 case NETDEV_UNREGISTER: 765 spin_lock(&can_rcvlists_lock); 766 767 d = find_dev_rcv_lists(dev); 768 if (d) { 769 if (d->entries) { 770 d->remove_on_zero_entries = 1; 771 d = NULL; 772 } else 773 hlist_del_rcu(&d->list); 774 } else 775 printk(KERN_ERR "can: notifier: receive list not " 776 "found for dev %s\n", dev->name); 777 778 spin_unlock(&can_rcvlists_lock); 779 780 if (d) 781 call_rcu(&d->rcu, can_rx_delete_device); 782 783 break; 784 } 785 786 return NOTIFY_DONE; 787 } 788 789 /* 790 * af_can module init/exit functions 791 */ 792 793 static struct packet_type can_packet __read_mostly = { 794 .type = __constant_htons(ETH_P_CAN), 795 .dev = NULL, 796 .func = can_rcv, 797 }; 798 799 static struct net_proto_family can_family_ops __read_mostly = { 800 .family = PF_CAN, 801 .create = can_create, 802 .owner = THIS_MODULE, 803 }; 804 805 /* notifier block for netdevice event */ 806 static struct notifier_block can_netdev_notifier __read_mostly = { 807 .notifier_call = can_notifier, 808 }; 809 810 static __init int can_init(void) 811 { 812 printk(banner); 813 814 rcv_cache = kmem_cache_create("can_receiver", sizeof(struct receiver), 815 0, 0, NULL); 816 if (!rcv_cache) 817 return -ENOMEM; 818 819 /* 820 * Insert can_rx_alldev_list for reception on all devices. 821 * This struct is zero initialized which is correct for the 822 * embedded hlist heads, the dev pointer, and the entries counter. 823 */ 824 825 spin_lock(&can_rcvlists_lock); 826 hlist_add_head_rcu(&can_rx_alldev_list.list, &can_rx_dev_list); 827 spin_unlock(&can_rcvlists_lock); 828 829 if (stats_timer) { 830 /* the statistics are updated every second (timer triggered) */ 831 setup_timer(&can_stattimer, can_stat_update, 0); 832 mod_timer(&can_stattimer, round_jiffies(jiffies + HZ)); 833 } else 834 can_stattimer.function = NULL; 835 836 can_init_proc(); 837 838 /* protocol register */ 839 sock_register(&can_family_ops); 840 register_netdevice_notifier(&can_netdev_notifier); 841 dev_add_pack(&can_packet); 842 843 return 0; 844 } 845 846 static __exit void can_exit(void) 847 { 848 struct dev_rcv_lists *d; 849 struct hlist_node *n, *next; 850 851 if (stats_timer) 852 del_timer(&can_stattimer); 853 854 can_remove_proc(); 855 856 /* protocol unregister */ 857 dev_remove_pack(&can_packet); 858 unregister_netdevice_notifier(&can_netdev_notifier); 859 sock_unregister(PF_CAN); 860 861 /* remove can_rx_dev_list */ 862 spin_lock(&can_rcvlists_lock); 863 hlist_del(&can_rx_alldev_list.list); 864 hlist_for_each_entry_safe(d, n, next, &can_rx_dev_list, list) { 865 hlist_del(&d->list); 866 kfree(d); 867 } 868 spin_unlock(&can_rcvlists_lock); 869 870 kmem_cache_destroy(rcv_cache); 871 } 872 873 module_init(can_init); 874 module_exit(can_exit); 875