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 */ 42 43 #include <linux/module.h> 44 #include <linux/stddef.h> 45 #include <linux/init.h> 46 #include <linux/kmod.h> 47 #include <linux/slab.h> 48 #include <linux/list.h> 49 #include <linux/spinlock.h> 50 #include <linux/rcupdate.h> 51 #include <linux/uaccess.h> 52 #include <linux/net.h> 53 #include <linux/netdevice.h> 54 #include <linux/socket.h> 55 #include <linux/if_ether.h> 56 #include <linux/if_arp.h> 57 #include <linux/skbuff.h> 58 #include <linux/can.h> 59 #include <linux/can/core.h> 60 #include <linux/ratelimit.h> 61 #include <net/net_namespace.h> 62 #include <net/sock.h> 63 64 #include "af_can.h" 65 66 static __initconst const char banner[] = KERN_INFO 67 "can: controller area network core (" CAN_VERSION_STRING ")\n"; 68 69 MODULE_DESCRIPTION("Controller Area Network PF_CAN core"); 70 MODULE_LICENSE("Dual BSD/GPL"); 71 MODULE_AUTHOR("Urs Thuermann <urs.thuermann@volkswagen.de>, " 72 "Oliver Hartkopp <oliver.hartkopp@volkswagen.de>"); 73 74 MODULE_ALIAS_NETPROTO(PF_CAN); 75 76 static int stats_timer __read_mostly = 1; 77 module_param(stats_timer, int, S_IRUGO); 78 MODULE_PARM_DESC(stats_timer, "enable timer for statistics (default:on)"); 79 80 /* receive filters subscribed for 'all' CAN devices */ 81 struct dev_rcv_lists can_rx_alldev_list; 82 static DEFINE_SPINLOCK(can_rcvlists_lock); 83 84 static struct kmem_cache *rcv_cache __read_mostly; 85 86 /* table of registered CAN protocols */ 87 static const struct can_proto *proto_tab[CAN_NPROTO] __read_mostly; 88 static DEFINE_MUTEX(proto_tab_lock); 89 90 struct timer_list can_stattimer; /* timer for statistics update */ 91 struct s_stats can_stats; /* packet statistics */ 92 struct s_pstats can_pstats; /* receive list statistics */ 93 94 /* 95 * af_can socket functions 96 */ 97 98 int can_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg) 99 { 100 struct sock *sk = sock->sk; 101 102 switch (cmd) { 103 104 case SIOCGSTAMP: 105 return sock_get_timestamp(sk, (struct timeval __user *)arg); 106 107 default: 108 return -ENOIOCTLCMD; 109 } 110 } 111 EXPORT_SYMBOL(can_ioctl); 112 113 static void can_sock_destruct(struct sock *sk) 114 { 115 skb_queue_purge(&sk->sk_receive_queue); 116 } 117 118 static const struct can_proto *can_get_proto(int protocol) 119 { 120 const struct can_proto *cp; 121 122 rcu_read_lock(); 123 cp = rcu_dereference(proto_tab[protocol]); 124 if (cp && !try_module_get(cp->prot->owner)) 125 cp = NULL; 126 rcu_read_unlock(); 127 128 return cp; 129 } 130 131 static inline void can_put_proto(const struct can_proto *cp) 132 { 133 module_put(cp->prot->owner); 134 } 135 136 static int can_create(struct net *net, struct socket *sock, int protocol, 137 int kern) 138 { 139 struct sock *sk; 140 const struct can_proto *cp; 141 int err = 0; 142 143 sock->state = SS_UNCONNECTED; 144 145 if (protocol < 0 || protocol >= CAN_NPROTO) 146 return -EINVAL; 147 148 if (!net_eq(net, &init_net)) 149 return -EAFNOSUPPORT; 150 151 cp = can_get_proto(protocol); 152 153 #ifdef CONFIG_MODULES 154 if (!cp) { 155 /* try to load protocol module if kernel is modular */ 156 157 err = request_module("can-proto-%d", protocol); 158 159 /* 160 * In case of error we only print a message but don't 161 * return the error code immediately. Below we will 162 * return -EPROTONOSUPPORT 163 */ 164 if (err) 165 printk_ratelimited(KERN_ERR "can: request_module " 166 "(can-proto-%d) failed.\n", protocol); 167 168 cp = can_get_proto(protocol); 169 } 170 #endif 171 172 /* check for available protocol and correct usage */ 173 174 if (!cp) 175 return -EPROTONOSUPPORT; 176 177 if (cp->type != sock->type) { 178 err = -EPROTOTYPE; 179 goto errout; 180 } 181 182 sock->ops = cp->ops; 183 184 sk = sk_alloc(net, PF_CAN, GFP_KERNEL, cp->prot); 185 if (!sk) { 186 err = -ENOMEM; 187 goto errout; 188 } 189 190 sock_init_data(sock, sk); 191 sk->sk_destruct = can_sock_destruct; 192 193 if (sk->sk_prot->init) 194 err = sk->sk_prot->init(sk); 195 196 if (err) { 197 /* release sk on errors */ 198 sock_orphan(sk); 199 sock_put(sk); 200 } 201 202 errout: 203 can_put_proto(cp); 204 return err; 205 } 206 207 /* 208 * af_can tx path 209 */ 210 211 /** 212 * can_send - transmit a CAN frame (optional with local loopback) 213 * @skb: pointer to socket buffer with CAN frame in data section 214 * @loop: loopback for listeners on local CAN sockets (recommended default!) 215 * 216 * Due to the loopback this routine must not be called from hardirq context. 217 * 218 * Return: 219 * 0 on success 220 * -ENETDOWN when the selected interface is down 221 * -ENOBUFS on full driver queue (see net_xmit_errno()) 222 * -ENOMEM when local loopback failed at calling skb_clone() 223 * -EPERM when trying to send on a non-CAN interface 224 * -EMSGSIZE CAN frame size is bigger than CAN interface MTU 225 * -EINVAL when the skb->data does not contain a valid CAN frame 226 */ 227 int can_send(struct sk_buff *skb, int loop) 228 { 229 struct sk_buff *newskb = NULL; 230 struct canfd_frame *cfd = (struct canfd_frame *)skb->data; 231 int err = -EINVAL; 232 233 if (skb->len == CAN_MTU) { 234 skb->protocol = htons(ETH_P_CAN); 235 if (unlikely(cfd->len > CAN_MAX_DLEN)) 236 goto inval_skb; 237 } else if (skb->len == CANFD_MTU) { 238 skb->protocol = htons(ETH_P_CANFD); 239 if (unlikely(cfd->len > CANFD_MAX_DLEN)) 240 goto inval_skb; 241 } else 242 goto inval_skb; 243 244 /* 245 * Make sure the CAN frame can pass the selected CAN netdevice. 246 * As structs can_frame and canfd_frame are similar, we can provide 247 * CAN FD frames to legacy CAN drivers as long as the length is <= 8 248 */ 249 if (unlikely(skb->len > skb->dev->mtu && cfd->len > CAN_MAX_DLEN)) { 250 err = -EMSGSIZE; 251 goto inval_skb; 252 } 253 254 if (unlikely(skb->dev->type != ARPHRD_CAN)) { 255 err = -EPERM; 256 goto inval_skb; 257 } 258 259 if (unlikely(!(skb->dev->flags & IFF_UP))) { 260 err = -ENETDOWN; 261 goto inval_skb; 262 } 263 264 skb_reset_network_header(skb); 265 skb_reset_transport_header(skb); 266 267 if (loop) { 268 /* local loopback of sent CAN frames */ 269 270 /* indication for the CAN driver: do loopback */ 271 skb->pkt_type = PACKET_LOOPBACK; 272 273 /* 274 * The reference to the originating sock may be required 275 * by the receiving socket to check whether the frame is 276 * its own. Example: can_raw sockopt CAN_RAW_RECV_OWN_MSGS 277 * Therefore we have to ensure that skb->sk remains the 278 * reference to the originating sock by restoring skb->sk 279 * after each skb_clone() or skb_orphan() usage. 280 */ 281 282 if (!(skb->dev->flags & IFF_ECHO)) { 283 /* 284 * If the interface is not capable to do loopback 285 * itself, we do it here. 286 */ 287 newskb = skb_clone(skb, GFP_ATOMIC); 288 if (!newskb) { 289 kfree_skb(skb); 290 return -ENOMEM; 291 } 292 293 newskb->sk = skb->sk; 294 newskb->ip_summed = CHECKSUM_UNNECESSARY; 295 newskb->pkt_type = PACKET_BROADCAST; 296 } 297 } else { 298 /* indication for the CAN driver: no loopback required */ 299 skb->pkt_type = PACKET_HOST; 300 } 301 302 /* send to netdevice */ 303 err = dev_queue_xmit(skb); 304 if (err > 0) 305 err = net_xmit_errno(err); 306 307 if (err) { 308 kfree_skb(newskb); 309 return err; 310 } 311 312 if (newskb) 313 netif_rx_ni(newskb); 314 315 /* update statistics */ 316 can_stats.tx_frames++; 317 can_stats.tx_frames_delta++; 318 319 return 0; 320 321 inval_skb: 322 kfree_skb(skb); 323 return err; 324 } 325 EXPORT_SYMBOL(can_send); 326 327 /* 328 * af_can rx path 329 */ 330 331 static struct dev_rcv_lists *find_dev_rcv_lists(struct net_device *dev) 332 { 333 if (!dev) 334 return &can_rx_alldev_list; 335 else 336 return (struct dev_rcv_lists *)dev->ml_priv; 337 } 338 339 /** 340 * find_rcv_list - determine optimal filterlist inside device filter struct 341 * @can_id: pointer to CAN identifier of a given can_filter 342 * @mask: pointer to CAN mask of a given can_filter 343 * @d: pointer to the device filter struct 344 * 345 * Description: 346 * Returns the optimal filterlist to reduce the filter handling in the 347 * receive path. This function is called by service functions that need 348 * to register or unregister a can_filter in the filter lists. 349 * 350 * A filter matches in general, when 351 * 352 * <received_can_id> & mask == can_id & mask 353 * 354 * so every bit set in the mask (even CAN_EFF_FLAG, CAN_RTR_FLAG) describe 355 * relevant bits for the filter. 356 * 357 * The filter can be inverted (CAN_INV_FILTER bit set in can_id) or it can 358 * filter for error messages (CAN_ERR_FLAG bit set in mask). For error msg 359 * frames there is a special filterlist and a special rx path filter handling. 360 * 361 * Return: 362 * Pointer to optimal filterlist for the given can_id/mask pair. 363 * Constistency checked mask. 364 * Reduced can_id to have a preprocessed filter compare value. 365 */ 366 static struct hlist_head *find_rcv_list(canid_t *can_id, canid_t *mask, 367 struct dev_rcv_lists *d) 368 { 369 canid_t inv = *can_id & CAN_INV_FILTER; /* save flag before masking */ 370 371 /* filter for error message frames in extra filterlist */ 372 if (*mask & CAN_ERR_FLAG) { 373 /* clear CAN_ERR_FLAG in filter entry */ 374 *mask &= CAN_ERR_MASK; 375 return &d->rx[RX_ERR]; 376 } 377 378 /* with cleared CAN_ERR_FLAG we have a simple mask/value filterpair */ 379 380 #define CAN_EFF_RTR_FLAGS (CAN_EFF_FLAG | CAN_RTR_FLAG) 381 382 /* ensure valid values in can_mask for 'SFF only' frame filtering */ 383 if ((*mask & CAN_EFF_FLAG) && !(*can_id & CAN_EFF_FLAG)) 384 *mask &= (CAN_SFF_MASK | CAN_EFF_RTR_FLAGS); 385 386 /* reduce condition testing at receive time */ 387 *can_id &= *mask; 388 389 /* inverse can_id/can_mask filter */ 390 if (inv) 391 return &d->rx[RX_INV]; 392 393 /* mask == 0 => no condition testing at receive time */ 394 if (!(*mask)) 395 return &d->rx[RX_ALL]; 396 397 /* extra filterlists for the subscription of a single non-RTR can_id */ 398 if (((*mask & CAN_EFF_RTR_FLAGS) == CAN_EFF_RTR_FLAGS) && 399 !(*can_id & CAN_RTR_FLAG)) { 400 401 if (*can_id & CAN_EFF_FLAG) { 402 if (*mask == (CAN_EFF_MASK | CAN_EFF_RTR_FLAGS)) { 403 /* RFC: a future use-case for hash-tables? */ 404 return &d->rx[RX_EFF]; 405 } 406 } else { 407 if (*mask == (CAN_SFF_MASK | CAN_EFF_RTR_FLAGS)) 408 return &d->rx_sff[*can_id]; 409 } 410 } 411 412 /* default: filter via can_id/can_mask */ 413 return &d->rx[RX_FIL]; 414 } 415 416 /** 417 * can_rx_register - subscribe CAN frames from a specific interface 418 * @dev: pointer to netdevice (NULL => subcribe from 'all' CAN devices list) 419 * @can_id: CAN identifier (see description) 420 * @mask: CAN mask (see description) 421 * @func: callback function on filter match 422 * @data: returned parameter for callback function 423 * @ident: string for calling module indentification 424 * 425 * Description: 426 * Invokes the callback function with the received sk_buff and the given 427 * parameter 'data' on a matching receive filter. A filter matches, when 428 * 429 * <received_can_id> & mask == can_id & mask 430 * 431 * The filter can be inverted (CAN_INV_FILTER bit set in can_id) or it can 432 * filter for error message frames (CAN_ERR_FLAG bit set in mask). 433 * 434 * The provided pointer to the sk_buff is guaranteed to be valid as long as 435 * the callback function is running. The callback function must *not* free 436 * the given sk_buff while processing it's task. When the given sk_buff is 437 * needed after the end of the callback function it must be cloned inside 438 * the callback function with skb_clone(). 439 * 440 * Return: 441 * 0 on success 442 * -ENOMEM on missing cache mem to create subscription entry 443 * -ENODEV unknown device 444 */ 445 int can_rx_register(struct net_device *dev, canid_t can_id, canid_t mask, 446 void (*func)(struct sk_buff *, void *), void *data, 447 char *ident) 448 { 449 struct receiver *r; 450 struct hlist_head *rl; 451 struct dev_rcv_lists *d; 452 int err = 0; 453 454 /* insert new receiver (dev,canid,mask) -> (func,data) */ 455 456 if (dev && dev->type != ARPHRD_CAN) 457 return -ENODEV; 458 459 r = kmem_cache_alloc(rcv_cache, GFP_KERNEL); 460 if (!r) 461 return -ENOMEM; 462 463 spin_lock(&can_rcvlists_lock); 464 465 d = find_dev_rcv_lists(dev); 466 if (d) { 467 rl = find_rcv_list(&can_id, &mask, d); 468 469 r->can_id = can_id; 470 r->mask = mask; 471 r->matches = 0; 472 r->func = func; 473 r->data = data; 474 r->ident = ident; 475 476 hlist_add_head_rcu(&r->list, rl); 477 d->entries++; 478 479 can_pstats.rcv_entries++; 480 if (can_pstats.rcv_entries_max < can_pstats.rcv_entries) 481 can_pstats.rcv_entries_max = can_pstats.rcv_entries; 482 } else { 483 kmem_cache_free(rcv_cache, r); 484 err = -ENODEV; 485 } 486 487 spin_unlock(&can_rcvlists_lock); 488 489 return err; 490 } 491 EXPORT_SYMBOL(can_rx_register); 492 493 /* 494 * can_rx_delete_receiver - rcu callback for single receiver entry removal 495 */ 496 static void can_rx_delete_receiver(struct rcu_head *rp) 497 { 498 struct receiver *r = container_of(rp, struct receiver, rcu); 499 500 kmem_cache_free(rcv_cache, r); 501 } 502 503 /** 504 * can_rx_unregister - unsubscribe CAN frames from a specific interface 505 * @dev: pointer to netdevice (NULL => unsubcribe from 'all' CAN devices list) 506 * @can_id: CAN identifier 507 * @mask: CAN mask 508 * @func: callback function on filter match 509 * @data: returned parameter for callback function 510 * 511 * Description: 512 * Removes subscription entry depending on given (subscription) values. 513 */ 514 void can_rx_unregister(struct net_device *dev, canid_t can_id, canid_t mask, 515 void (*func)(struct sk_buff *, void *), void *data) 516 { 517 struct receiver *r = NULL; 518 struct hlist_head *rl; 519 struct hlist_node *next; 520 struct dev_rcv_lists *d; 521 522 if (dev && dev->type != ARPHRD_CAN) 523 return; 524 525 spin_lock(&can_rcvlists_lock); 526 527 d = find_dev_rcv_lists(dev); 528 if (!d) { 529 printk(KERN_ERR "BUG: receive list not found for " 530 "dev %s, id %03X, mask %03X\n", 531 DNAME(dev), can_id, mask); 532 goto out; 533 } 534 535 rl = find_rcv_list(&can_id, &mask, d); 536 537 /* 538 * Search the receiver list for the item to delete. This should 539 * exist, since no receiver may be unregistered that hasn't 540 * been registered before. 541 */ 542 543 hlist_for_each_entry_rcu(r, next, rl, list) { 544 if (r->can_id == can_id && r->mask == mask && 545 r->func == func && r->data == data) 546 break; 547 } 548 549 /* 550 * Check for bugs in CAN protocol implementations: 551 * If no matching list item was found, the list cursor variable next 552 * will be NULL, while r will point to the last item of the list. 553 */ 554 555 if (!next) { 556 printk(KERN_ERR "BUG: receive list entry not found for " 557 "dev %s, id %03X, mask %03X\n", 558 DNAME(dev), can_id, mask); 559 r = NULL; 560 goto out; 561 } 562 563 hlist_del_rcu(&r->list); 564 d->entries--; 565 566 if (can_pstats.rcv_entries > 0) 567 can_pstats.rcv_entries--; 568 569 /* remove device structure requested by NETDEV_UNREGISTER */ 570 if (d->remove_on_zero_entries && !d->entries) { 571 kfree(d); 572 dev->ml_priv = NULL; 573 } 574 575 out: 576 spin_unlock(&can_rcvlists_lock); 577 578 /* schedule the receiver item for deletion */ 579 if (r) 580 call_rcu(&r->rcu, can_rx_delete_receiver); 581 } 582 EXPORT_SYMBOL(can_rx_unregister); 583 584 static inline void deliver(struct sk_buff *skb, struct receiver *r) 585 { 586 r->func(skb, r->data); 587 r->matches++; 588 } 589 590 static int can_rcv_filter(struct dev_rcv_lists *d, struct sk_buff *skb) 591 { 592 struct receiver *r; 593 struct hlist_node *n; 594 int matches = 0; 595 struct can_frame *cf = (struct can_frame *)skb->data; 596 canid_t can_id = cf->can_id; 597 598 if (d->entries == 0) 599 return 0; 600 601 if (can_id & CAN_ERR_FLAG) { 602 /* check for error message frame entries only */ 603 hlist_for_each_entry_rcu(r, n, &d->rx[RX_ERR], list) { 604 if (can_id & r->mask) { 605 deliver(skb, r); 606 matches++; 607 } 608 } 609 return matches; 610 } 611 612 /* check for unfiltered entries */ 613 hlist_for_each_entry_rcu(r, n, &d->rx[RX_ALL], list) { 614 deliver(skb, r); 615 matches++; 616 } 617 618 /* check for can_id/mask entries */ 619 hlist_for_each_entry_rcu(r, n, &d->rx[RX_FIL], list) { 620 if ((can_id & r->mask) == r->can_id) { 621 deliver(skb, r); 622 matches++; 623 } 624 } 625 626 /* check for inverted can_id/mask entries */ 627 hlist_for_each_entry_rcu(r, n, &d->rx[RX_INV], list) { 628 if ((can_id & r->mask) != r->can_id) { 629 deliver(skb, r); 630 matches++; 631 } 632 } 633 634 /* check filterlists for single non-RTR can_ids */ 635 if (can_id & CAN_RTR_FLAG) 636 return matches; 637 638 if (can_id & CAN_EFF_FLAG) { 639 hlist_for_each_entry_rcu(r, n, &d->rx[RX_EFF], list) { 640 if (r->can_id == can_id) { 641 deliver(skb, r); 642 matches++; 643 } 644 } 645 } else { 646 can_id &= CAN_SFF_MASK; 647 hlist_for_each_entry_rcu(r, n, &d->rx_sff[can_id], list) { 648 deliver(skb, r); 649 matches++; 650 } 651 } 652 653 return matches; 654 } 655 656 static void can_receive(struct sk_buff *skb, struct net_device *dev) 657 { 658 struct dev_rcv_lists *d; 659 int matches; 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 /* consume the skbuff allocated by the netdevice driver */ 678 consume_skb(skb); 679 680 if (matches > 0) { 681 can_stats.matches++; 682 can_stats.matches_delta++; 683 } 684 } 685 686 static int can_rcv(struct sk_buff *skb, struct net_device *dev, 687 struct packet_type *pt, struct net_device *orig_dev) 688 { 689 struct canfd_frame *cfd = (struct canfd_frame *)skb->data; 690 691 if (unlikely(!net_eq(dev_net(dev), &init_net))) 692 goto drop; 693 694 if (WARN_ONCE(dev->type != ARPHRD_CAN || 695 skb->len != CAN_MTU || 696 cfd->len > CAN_MAX_DLEN, 697 "PF_CAN: dropped non conform CAN skbuf: " 698 "dev type %d, len %d, datalen %d\n", 699 dev->type, skb->len, cfd->len)) 700 goto drop; 701 702 can_receive(skb, dev); 703 return NET_RX_SUCCESS; 704 705 drop: 706 kfree_skb(skb); 707 return NET_RX_DROP; 708 } 709 710 static int canfd_rcv(struct sk_buff *skb, struct net_device *dev, 711 struct packet_type *pt, struct net_device *orig_dev) 712 { 713 struct canfd_frame *cfd = (struct canfd_frame *)skb->data; 714 715 if (unlikely(!net_eq(dev_net(dev), &init_net))) 716 goto drop; 717 718 if (WARN_ONCE(dev->type != ARPHRD_CAN || 719 skb->len != CANFD_MTU || 720 cfd->len > CANFD_MAX_DLEN, 721 "PF_CAN: dropped non conform CAN FD skbuf: " 722 "dev type %d, len %d, datalen %d\n", 723 dev->type, skb->len, cfd->len)) 724 goto drop; 725 726 can_receive(skb, dev); 727 return NET_RX_SUCCESS; 728 729 drop: 730 kfree_skb(skb); 731 return NET_RX_DROP; 732 } 733 734 /* 735 * af_can protocol functions 736 */ 737 738 /** 739 * can_proto_register - register CAN transport protocol 740 * @cp: pointer to CAN protocol structure 741 * 742 * Return: 743 * 0 on success 744 * -EINVAL invalid (out of range) protocol number 745 * -EBUSY protocol already in use 746 * -ENOBUF if proto_register() fails 747 */ 748 int can_proto_register(const struct can_proto *cp) 749 { 750 int proto = cp->protocol; 751 int err = 0; 752 753 if (proto < 0 || proto >= CAN_NPROTO) { 754 printk(KERN_ERR "can: protocol number %d out of range\n", 755 proto); 756 return -EINVAL; 757 } 758 759 err = proto_register(cp->prot, 0); 760 if (err < 0) 761 return err; 762 763 mutex_lock(&proto_tab_lock); 764 765 if (proto_tab[proto]) { 766 printk(KERN_ERR "can: protocol %d already registered\n", 767 proto); 768 err = -EBUSY; 769 } else 770 RCU_INIT_POINTER(proto_tab[proto], cp); 771 772 mutex_unlock(&proto_tab_lock); 773 774 if (err < 0) 775 proto_unregister(cp->prot); 776 777 return err; 778 } 779 EXPORT_SYMBOL(can_proto_register); 780 781 /** 782 * can_proto_unregister - unregister CAN transport protocol 783 * @cp: pointer to CAN protocol structure 784 */ 785 void can_proto_unregister(const struct can_proto *cp) 786 { 787 int proto = cp->protocol; 788 789 mutex_lock(&proto_tab_lock); 790 BUG_ON(proto_tab[proto] != cp); 791 RCU_INIT_POINTER(proto_tab[proto], NULL); 792 mutex_unlock(&proto_tab_lock); 793 794 synchronize_rcu(); 795 796 proto_unregister(cp->prot); 797 } 798 EXPORT_SYMBOL(can_proto_unregister); 799 800 /* 801 * af_can notifier to create/remove CAN netdevice specific structs 802 */ 803 static int can_notifier(struct notifier_block *nb, unsigned long msg, 804 void *data) 805 { 806 struct net_device *dev = (struct net_device *)data; 807 struct dev_rcv_lists *d; 808 809 if (!net_eq(dev_net(dev), &init_net)) 810 return NOTIFY_DONE; 811 812 if (dev->type != ARPHRD_CAN) 813 return NOTIFY_DONE; 814 815 switch (msg) { 816 817 case NETDEV_REGISTER: 818 819 /* create new dev_rcv_lists for this device */ 820 d = kzalloc(sizeof(*d), GFP_KERNEL); 821 if (!d) { 822 printk(KERN_ERR 823 "can: allocation of receive list failed\n"); 824 return NOTIFY_DONE; 825 } 826 BUG_ON(dev->ml_priv); 827 dev->ml_priv = d; 828 829 break; 830 831 case NETDEV_UNREGISTER: 832 spin_lock(&can_rcvlists_lock); 833 834 d = dev->ml_priv; 835 if (d) { 836 if (d->entries) 837 d->remove_on_zero_entries = 1; 838 else { 839 kfree(d); 840 dev->ml_priv = NULL; 841 } 842 } else 843 printk(KERN_ERR "can: notifier: receive list not " 844 "found for dev %s\n", dev->name); 845 846 spin_unlock(&can_rcvlists_lock); 847 848 break; 849 } 850 851 return NOTIFY_DONE; 852 } 853 854 /* 855 * af_can module init/exit functions 856 */ 857 858 static struct packet_type can_packet __read_mostly = { 859 .type = cpu_to_be16(ETH_P_CAN), 860 .func = can_rcv, 861 }; 862 863 static struct packet_type canfd_packet __read_mostly = { 864 .type = cpu_to_be16(ETH_P_CANFD), 865 .func = canfd_rcv, 866 }; 867 868 static const struct net_proto_family can_family_ops = { 869 .family = PF_CAN, 870 .create = can_create, 871 .owner = THIS_MODULE, 872 }; 873 874 /* notifier block for netdevice event */ 875 static struct notifier_block can_netdev_notifier __read_mostly = { 876 .notifier_call = can_notifier, 877 }; 878 879 static __init int can_init(void) 880 { 881 /* check for correct padding to be able to use the structs similarly */ 882 BUILD_BUG_ON(offsetof(struct can_frame, can_dlc) != 883 offsetof(struct canfd_frame, len) || 884 offsetof(struct can_frame, data) != 885 offsetof(struct canfd_frame, data)); 886 887 printk(banner); 888 889 memset(&can_rx_alldev_list, 0, sizeof(can_rx_alldev_list)); 890 891 rcv_cache = kmem_cache_create("can_receiver", sizeof(struct receiver), 892 0, 0, NULL); 893 if (!rcv_cache) 894 return -ENOMEM; 895 896 if (stats_timer) { 897 /* the statistics are updated every second (timer triggered) */ 898 setup_timer(&can_stattimer, can_stat_update, 0); 899 mod_timer(&can_stattimer, round_jiffies(jiffies + HZ)); 900 } else 901 can_stattimer.function = NULL; 902 903 can_init_proc(); 904 905 /* protocol register */ 906 sock_register(&can_family_ops); 907 register_netdevice_notifier(&can_netdev_notifier); 908 dev_add_pack(&can_packet); 909 dev_add_pack(&canfd_packet); 910 911 return 0; 912 } 913 914 static __exit void can_exit(void) 915 { 916 struct net_device *dev; 917 918 if (stats_timer) 919 del_timer_sync(&can_stattimer); 920 921 can_remove_proc(); 922 923 /* protocol unregister */ 924 dev_remove_pack(&canfd_packet); 925 dev_remove_pack(&can_packet); 926 unregister_netdevice_notifier(&can_netdev_notifier); 927 sock_unregister(PF_CAN); 928 929 /* remove created dev_rcv_lists from still registered CAN devices */ 930 rcu_read_lock(); 931 for_each_netdev_rcu(&init_net, dev) { 932 if (dev->type == ARPHRD_CAN && dev->ml_priv){ 933 934 struct dev_rcv_lists *d = dev->ml_priv; 935 936 BUG_ON(d->entries); 937 kfree(d); 938 dev->ml_priv = NULL; 939 } 940 } 941 rcu_read_unlock(); 942 943 rcu_barrier(); /* Wait for completion of call_rcu()'s */ 944 945 kmem_cache_destroy(rcv_cache); 946 } 947 948 module_init(can_init); 949 module_exit(can_exit); 950