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/can/skb.h> 61 #include <linux/ratelimit.h> 62 #include <net/net_namespace.h> 63 #include <net/sock.h> 64 65 #include "af_can.h" 66 67 MODULE_DESCRIPTION("Controller Area Network PF_CAN core"); 68 MODULE_LICENSE("Dual BSD/GPL"); 69 MODULE_AUTHOR("Urs Thuermann <urs.thuermann@volkswagen.de>, " 70 "Oliver Hartkopp <oliver.hartkopp@volkswagen.de>"); 71 72 MODULE_ALIAS_NETPROTO(PF_CAN); 73 74 static int stats_timer __read_mostly = 1; 75 module_param(stats_timer, int, S_IRUGO); 76 MODULE_PARM_DESC(stats_timer, "enable timer for statistics (default:on)"); 77 78 /* receive filters subscribed for 'all' CAN devices */ 79 struct dev_rcv_lists can_rx_alldev_list; 80 static DEFINE_SPINLOCK(can_rcvlists_lock); 81 82 static struct kmem_cache *rcv_cache __read_mostly; 83 84 /* table of registered CAN protocols */ 85 static const struct can_proto *proto_tab[CAN_NPROTO] __read_mostly; 86 static DEFINE_MUTEX(proto_tab_lock); 87 88 struct timer_list can_stattimer; /* timer for statistics update */ 89 struct s_stats can_stats; /* packet statistics */ 90 struct s_pstats can_pstats; /* receive list statistics */ 91 92 /* 93 * af_can socket functions 94 */ 95 96 int can_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg) 97 { 98 struct sock *sk = sock->sk; 99 100 switch (cmd) { 101 102 case SIOCGSTAMP: 103 return sock_get_timestamp(sk, (struct timeval __user *)arg); 104 105 default: 106 return -ENOIOCTLCMD; 107 } 108 } 109 EXPORT_SYMBOL(can_ioctl); 110 111 static void can_sock_destruct(struct sock *sk) 112 { 113 skb_queue_purge(&sk->sk_receive_queue); 114 } 115 116 static const struct can_proto *can_get_proto(int protocol) 117 { 118 const struct can_proto *cp; 119 120 rcu_read_lock(); 121 cp = rcu_dereference(proto_tab[protocol]); 122 if (cp && !try_module_get(cp->prot->owner)) 123 cp = NULL; 124 rcu_read_unlock(); 125 126 return cp; 127 } 128 129 static inline void can_put_proto(const struct can_proto *cp) 130 { 131 module_put(cp->prot->owner); 132 } 133 134 static int can_create(struct net *net, struct socket *sock, int protocol, 135 int kern) 136 { 137 struct sock *sk; 138 const struct can_proto *cp; 139 int err = 0; 140 141 sock->state = SS_UNCONNECTED; 142 143 if (protocol < 0 || protocol >= CAN_NPROTO) 144 return -EINVAL; 145 146 if (!net_eq(net, &init_net)) 147 return -EAFNOSUPPORT; 148 149 cp = can_get_proto(protocol); 150 151 #ifdef CONFIG_MODULES 152 if (!cp) { 153 /* try to load protocol module if kernel is modular */ 154 155 err = request_module("can-proto-%d", protocol); 156 157 /* 158 * In case of error we only print a message but don't 159 * return the error code immediately. Below we will 160 * return -EPROTONOSUPPORT 161 */ 162 if (err) 163 printk_ratelimited(KERN_ERR "can: request_module " 164 "(can-proto-%d) failed.\n", protocol); 165 166 cp = can_get_proto(protocol); 167 } 168 #endif 169 170 /* check for available protocol and correct usage */ 171 172 if (!cp) 173 return -EPROTONOSUPPORT; 174 175 if (cp->type != sock->type) { 176 err = -EPROTOTYPE; 177 goto errout; 178 } 179 180 sock->ops = cp->ops; 181 182 sk = sk_alloc(net, PF_CAN, GFP_KERNEL, cp->prot, kern); 183 if (!sk) { 184 err = -ENOMEM; 185 goto errout; 186 } 187 188 sock_init_data(sock, sk); 189 sk->sk_destruct = can_sock_destruct; 190 191 if (sk->sk_prot->init) 192 err = sk->sk_prot->init(sk); 193 194 if (err) { 195 /* release sk on errors */ 196 sock_orphan(sk); 197 sock_put(sk); 198 } 199 200 errout: 201 can_put_proto(cp); 202 return err; 203 } 204 205 /* 206 * af_can tx path 207 */ 208 209 /** 210 * can_send - transmit a CAN frame (optional with local loopback) 211 * @skb: pointer to socket buffer with CAN frame in data section 212 * @loop: loopback for listeners on local CAN sockets (recommended default!) 213 * 214 * Due to the loopback this routine must not be called from hardirq context. 215 * 216 * Return: 217 * 0 on success 218 * -ENETDOWN when the selected interface is down 219 * -ENOBUFS on full driver queue (see net_xmit_errno()) 220 * -ENOMEM when local loopback failed at calling skb_clone() 221 * -EPERM when trying to send on a non-CAN interface 222 * -EMSGSIZE CAN frame size is bigger than CAN interface MTU 223 * -EINVAL when the skb->data does not contain a valid CAN frame 224 */ 225 int can_send(struct sk_buff *skb, int loop) 226 { 227 struct sk_buff *newskb = NULL; 228 struct canfd_frame *cfd = (struct canfd_frame *)skb->data; 229 int err = -EINVAL; 230 231 if (skb->len == CAN_MTU) { 232 skb->protocol = htons(ETH_P_CAN); 233 if (unlikely(cfd->len > CAN_MAX_DLEN)) 234 goto inval_skb; 235 } else if (skb->len == CANFD_MTU) { 236 skb->protocol = htons(ETH_P_CANFD); 237 if (unlikely(cfd->len > CANFD_MAX_DLEN)) 238 goto inval_skb; 239 } else 240 goto inval_skb; 241 242 /* 243 * Make sure the CAN frame can pass the selected CAN netdevice. 244 * As structs can_frame and canfd_frame are similar, we can provide 245 * CAN FD frames to legacy CAN drivers as long as the length is <= 8 246 */ 247 if (unlikely(skb->len > skb->dev->mtu && cfd->len > CAN_MAX_DLEN)) { 248 err = -EMSGSIZE; 249 goto inval_skb; 250 } 251 252 if (unlikely(skb->dev->type != ARPHRD_CAN)) { 253 err = -EPERM; 254 goto inval_skb; 255 } 256 257 if (unlikely(!(skb->dev->flags & IFF_UP))) { 258 err = -ENETDOWN; 259 goto inval_skb; 260 } 261 262 skb->ip_summed = CHECKSUM_UNNECESSARY; 263 264 skb_reset_mac_header(skb); 265 skb_reset_network_header(skb); 266 skb_reset_transport_header(skb); 267 268 if (loop) { 269 /* local loopback of sent CAN frames */ 270 271 /* indication for the CAN driver: do loopback */ 272 skb->pkt_type = PACKET_LOOPBACK; 273 274 /* 275 * The reference to the originating sock may be required 276 * by the receiving socket to check whether the frame is 277 * its own. Example: can_raw sockopt CAN_RAW_RECV_OWN_MSGS 278 * Therefore we have to ensure that skb->sk remains the 279 * reference to the originating sock by restoring skb->sk 280 * after each skb_clone() or skb_orphan() usage. 281 */ 282 283 if (!(skb->dev->flags & IFF_ECHO)) { 284 /* 285 * If the interface is not capable to do loopback 286 * itself, we do it here. 287 */ 288 newskb = skb_clone(skb, GFP_ATOMIC); 289 if (!newskb) { 290 kfree_skb(skb); 291 return -ENOMEM; 292 } 293 294 can_skb_set_owner(newskb, skb->sk); 295 newskb->ip_summed = CHECKSUM_UNNECESSARY; 296 newskb->pkt_type = PACKET_BROADCAST; 297 } 298 } else { 299 /* indication for the CAN driver: no loopback required */ 300 skb->pkt_type = PACKET_HOST; 301 } 302 303 /* send to netdevice */ 304 err = dev_queue_xmit(skb); 305 if (err > 0) 306 err = net_xmit_errno(err); 307 308 if (err) { 309 kfree_skb(newskb); 310 return err; 311 } 312 313 if (newskb) { 314 if (!(newskb->tstamp.tv64)) 315 __net_timestamp(newskb); 316 317 netif_rx_ni(newskb); 318 } 319 320 /* update statistics */ 321 can_stats.tx_frames++; 322 can_stats.tx_frames_delta++; 323 324 return 0; 325 326 inval_skb: 327 kfree_skb(skb); 328 return err; 329 } 330 EXPORT_SYMBOL(can_send); 331 332 /* 333 * af_can rx path 334 */ 335 336 static struct dev_rcv_lists *find_dev_rcv_lists(struct net_device *dev) 337 { 338 if (!dev) 339 return &can_rx_alldev_list; 340 else 341 return (struct dev_rcv_lists *)dev->ml_priv; 342 } 343 344 /** 345 * effhash - hash function for 29 bit CAN identifier reduction 346 * @can_id: 29 bit CAN identifier 347 * 348 * Description: 349 * To reduce the linear traversal in one linked list of _single_ EFF CAN 350 * frame subscriptions the 29 bit identifier is mapped to 10 bits. 351 * (see CAN_EFF_RCV_HASH_BITS definition) 352 * 353 * Return: 354 * Hash value from 0x000 - 0x3FF ( enforced by CAN_EFF_RCV_HASH_BITS mask ) 355 */ 356 static unsigned int effhash(canid_t can_id) 357 { 358 unsigned int hash; 359 360 hash = can_id; 361 hash ^= can_id >> CAN_EFF_RCV_HASH_BITS; 362 hash ^= can_id >> (2 * CAN_EFF_RCV_HASH_BITS); 363 364 return hash & ((1 << CAN_EFF_RCV_HASH_BITS) - 1); 365 } 366 367 /** 368 * find_rcv_list - determine optimal filterlist inside device filter struct 369 * @can_id: pointer to CAN identifier of a given can_filter 370 * @mask: pointer to CAN mask of a given can_filter 371 * @d: pointer to the device filter struct 372 * 373 * Description: 374 * Returns the optimal filterlist to reduce the filter handling in the 375 * receive path. This function is called by service functions that need 376 * to register or unregister a can_filter in the filter lists. 377 * 378 * A filter matches in general, when 379 * 380 * <received_can_id> & mask == can_id & mask 381 * 382 * so every bit set in the mask (even CAN_EFF_FLAG, CAN_RTR_FLAG) describe 383 * relevant bits for the filter. 384 * 385 * The filter can be inverted (CAN_INV_FILTER bit set in can_id) or it can 386 * filter for error messages (CAN_ERR_FLAG bit set in mask). For error msg 387 * frames there is a special filterlist and a special rx path filter handling. 388 * 389 * Return: 390 * Pointer to optimal filterlist for the given can_id/mask pair. 391 * Constistency checked mask. 392 * Reduced can_id to have a preprocessed filter compare value. 393 */ 394 static struct hlist_head *find_rcv_list(canid_t *can_id, canid_t *mask, 395 struct dev_rcv_lists *d) 396 { 397 canid_t inv = *can_id & CAN_INV_FILTER; /* save flag before masking */ 398 399 /* filter for error message frames in extra filterlist */ 400 if (*mask & CAN_ERR_FLAG) { 401 /* clear CAN_ERR_FLAG in filter entry */ 402 *mask &= CAN_ERR_MASK; 403 return &d->rx[RX_ERR]; 404 } 405 406 /* with cleared CAN_ERR_FLAG we have a simple mask/value filterpair */ 407 408 #define CAN_EFF_RTR_FLAGS (CAN_EFF_FLAG | CAN_RTR_FLAG) 409 410 /* ensure valid values in can_mask for 'SFF only' frame filtering */ 411 if ((*mask & CAN_EFF_FLAG) && !(*can_id & CAN_EFF_FLAG)) 412 *mask &= (CAN_SFF_MASK | CAN_EFF_RTR_FLAGS); 413 414 /* reduce condition testing at receive time */ 415 *can_id &= *mask; 416 417 /* inverse can_id/can_mask filter */ 418 if (inv) 419 return &d->rx[RX_INV]; 420 421 /* mask == 0 => no condition testing at receive time */ 422 if (!(*mask)) 423 return &d->rx[RX_ALL]; 424 425 /* extra filterlists for the subscription of a single non-RTR can_id */ 426 if (((*mask & CAN_EFF_RTR_FLAGS) == CAN_EFF_RTR_FLAGS) && 427 !(*can_id & CAN_RTR_FLAG)) { 428 429 if (*can_id & CAN_EFF_FLAG) { 430 if (*mask == (CAN_EFF_MASK | CAN_EFF_RTR_FLAGS)) 431 return &d->rx_eff[effhash(*can_id)]; 432 } else { 433 if (*mask == (CAN_SFF_MASK | CAN_EFF_RTR_FLAGS)) 434 return &d->rx_sff[*can_id]; 435 } 436 } 437 438 /* default: filter via can_id/can_mask */ 439 return &d->rx[RX_FIL]; 440 } 441 442 /** 443 * can_rx_register - subscribe CAN frames from a specific interface 444 * @dev: pointer to netdevice (NULL => subcribe from 'all' CAN devices list) 445 * @can_id: CAN identifier (see description) 446 * @mask: CAN mask (see description) 447 * @func: callback function on filter match 448 * @data: returned parameter for callback function 449 * @ident: string for calling module identification 450 * 451 * Description: 452 * Invokes the callback function with the received sk_buff and the given 453 * parameter 'data' on a matching receive filter. A filter matches, when 454 * 455 * <received_can_id> & mask == can_id & mask 456 * 457 * The filter can be inverted (CAN_INV_FILTER bit set in can_id) or it can 458 * filter for error message frames (CAN_ERR_FLAG bit set in mask). 459 * 460 * The provided pointer to the sk_buff is guaranteed to be valid as long as 461 * the callback function is running. The callback function must *not* free 462 * the given sk_buff while processing it's task. When the given sk_buff is 463 * needed after the end of the callback function it must be cloned inside 464 * the callback function with skb_clone(). 465 * 466 * Return: 467 * 0 on success 468 * -ENOMEM on missing cache mem to create subscription entry 469 * -ENODEV unknown device 470 */ 471 int can_rx_register(struct net_device *dev, canid_t can_id, canid_t mask, 472 void (*func)(struct sk_buff *, void *), void *data, 473 char *ident) 474 { 475 struct receiver *r; 476 struct hlist_head *rl; 477 struct dev_rcv_lists *d; 478 int err = 0; 479 480 /* insert new receiver (dev,canid,mask) -> (func,data) */ 481 482 if (dev && dev->type != ARPHRD_CAN) 483 return -ENODEV; 484 485 r = kmem_cache_alloc(rcv_cache, GFP_KERNEL); 486 if (!r) 487 return -ENOMEM; 488 489 spin_lock(&can_rcvlists_lock); 490 491 d = find_dev_rcv_lists(dev); 492 if (d) { 493 rl = find_rcv_list(&can_id, &mask, d); 494 495 r->can_id = can_id; 496 r->mask = mask; 497 r->matches = 0; 498 r->func = func; 499 r->data = data; 500 r->ident = ident; 501 502 hlist_add_head_rcu(&r->list, rl); 503 d->entries++; 504 505 can_pstats.rcv_entries++; 506 if (can_pstats.rcv_entries_max < can_pstats.rcv_entries) 507 can_pstats.rcv_entries_max = can_pstats.rcv_entries; 508 } else { 509 kmem_cache_free(rcv_cache, r); 510 err = -ENODEV; 511 } 512 513 spin_unlock(&can_rcvlists_lock); 514 515 return err; 516 } 517 EXPORT_SYMBOL(can_rx_register); 518 519 /* 520 * can_rx_delete_receiver - rcu callback for single receiver entry removal 521 */ 522 static void can_rx_delete_receiver(struct rcu_head *rp) 523 { 524 struct receiver *r = container_of(rp, struct receiver, rcu); 525 526 kmem_cache_free(rcv_cache, r); 527 } 528 529 /** 530 * can_rx_unregister - unsubscribe CAN frames from a specific interface 531 * @dev: pointer to netdevice (NULL => unsubscribe from 'all' CAN devices list) 532 * @can_id: CAN identifier 533 * @mask: CAN mask 534 * @func: callback function on filter match 535 * @data: returned parameter for callback function 536 * 537 * Description: 538 * Removes subscription entry depending on given (subscription) values. 539 */ 540 void can_rx_unregister(struct net_device *dev, canid_t can_id, canid_t mask, 541 void (*func)(struct sk_buff *, void *), void *data) 542 { 543 struct receiver *r = NULL; 544 struct hlist_head *rl; 545 struct dev_rcv_lists *d; 546 547 if (dev && dev->type != ARPHRD_CAN) 548 return; 549 550 spin_lock(&can_rcvlists_lock); 551 552 d = find_dev_rcv_lists(dev); 553 if (!d) { 554 pr_err("BUG: receive list not found for " 555 "dev %s, id %03X, mask %03X\n", 556 DNAME(dev), can_id, mask); 557 goto out; 558 } 559 560 rl = find_rcv_list(&can_id, &mask, d); 561 562 /* 563 * Search the receiver list for the item to delete. This should 564 * exist, since no receiver may be unregistered that hasn't 565 * been registered before. 566 */ 567 568 hlist_for_each_entry_rcu(r, rl, list) { 569 if (r->can_id == can_id && r->mask == mask && 570 r->func == func && r->data == data) 571 break; 572 } 573 574 /* 575 * Check for bugs in CAN protocol implementations using af_can.c: 576 * 'r' will be NULL if no matching list item was found for removal. 577 */ 578 579 if (!r) { 580 WARN(1, "BUG: receive list entry not found for dev %s, " 581 "id %03X, mask %03X\n", DNAME(dev), can_id, mask); 582 goto out; 583 } 584 585 hlist_del_rcu(&r->list); 586 d->entries--; 587 588 if (can_pstats.rcv_entries > 0) 589 can_pstats.rcv_entries--; 590 591 /* remove device structure requested by NETDEV_UNREGISTER */ 592 if (d->remove_on_zero_entries && !d->entries) { 593 kfree(d); 594 dev->ml_priv = NULL; 595 } 596 597 out: 598 spin_unlock(&can_rcvlists_lock); 599 600 /* schedule the receiver item for deletion */ 601 if (r) 602 call_rcu(&r->rcu, can_rx_delete_receiver); 603 } 604 EXPORT_SYMBOL(can_rx_unregister); 605 606 static inline void deliver(struct sk_buff *skb, struct receiver *r) 607 { 608 r->func(skb, r->data); 609 r->matches++; 610 } 611 612 static int can_rcv_filter(struct dev_rcv_lists *d, struct sk_buff *skb) 613 { 614 struct receiver *r; 615 int matches = 0; 616 struct can_frame *cf = (struct can_frame *)skb->data; 617 canid_t can_id = cf->can_id; 618 619 if (d->entries == 0) 620 return 0; 621 622 if (can_id & CAN_ERR_FLAG) { 623 /* check for error message frame entries only */ 624 hlist_for_each_entry_rcu(r, &d->rx[RX_ERR], list) { 625 if (can_id & r->mask) { 626 deliver(skb, r); 627 matches++; 628 } 629 } 630 return matches; 631 } 632 633 /* check for unfiltered entries */ 634 hlist_for_each_entry_rcu(r, &d->rx[RX_ALL], list) { 635 deliver(skb, r); 636 matches++; 637 } 638 639 /* check for can_id/mask entries */ 640 hlist_for_each_entry_rcu(r, &d->rx[RX_FIL], list) { 641 if ((can_id & r->mask) == r->can_id) { 642 deliver(skb, r); 643 matches++; 644 } 645 } 646 647 /* check for inverted can_id/mask entries */ 648 hlist_for_each_entry_rcu(r, &d->rx[RX_INV], list) { 649 if ((can_id & r->mask) != r->can_id) { 650 deliver(skb, r); 651 matches++; 652 } 653 } 654 655 /* check filterlists for single non-RTR can_ids */ 656 if (can_id & CAN_RTR_FLAG) 657 return matches; 658 659 if (can_id & CAN_EFF_FLAG) { 660 hlist_for_each_entry_rcu(r, &d->rx_eff[effhash(can_id)], list) { 661 if (r->can_id == can_id) { 662 deliver(skb, r); 663 matches++; 664 } 665 } 666 } else { 667 can_id &= CAN_SFF_MASK; 668 hlist_for_each_entry_rcu(r, &d->rx_sff[can_id], list) { 669 deliver(skb, r); 670 matches++; 671 } 672 } 673 674 return matches; 675 } 676 677 static void can_receive(struct sk_buff *skb, struct net_device *dev) 678 { 679 struct dev_rcv_lists *d; 680 int matches; 681 682 /* update statistics */ 683 can_stats.rx_frames++; 684 can_stats.rx_frames_delta++; 685 686 rcu_read_lock(); 687 688 /* deliver the packet to sockets listening on all devices */ 689 matches = can_rcv_filter(&can_rx_alldev_list, skb); 690 691 /* find receive list for this device */ 692 d = find_dev_rcv_lists(dev); 693 if (d) 694 matches += can_rcv_filter(d, skb); 695 696 rcu_read_unlock(); 697 698 /* consume the skbuff allocated by the netdevice driver */ 699 consume_skb(skb); 700 701 if (matches > 0) { 702 can_stats.matches++; 703 can_stats.matches_delta++; 704 } 705 } 706 707 static int can_rcv(struct sk_buff *skb, struct net_device *dev, 708 struct packet_type *pt, struct net_device *orig_dev) 709 { 710 struct canfd_frame *cfd = (struct canfd_frame *)skb->data; 711 712 if (unlikely(!net_eq(dev_net(dev), &init_net))) 713 goto drop; 714 715 if (WARN_ONCE(dev->type != ARPHRD_CAN || 716 skb->len != CAN_MTU || 717 cfd->len > CAN_MAX_DLEN, 718 "PF_CAN: dropped non conform CAN skbuf: " 719 "dev type %d, len %d, datalen %d\n", 720 dev->type, skb->len, cfd->len)) 721 goto drop; 722 723 can_receive(skb, dev); 724 return NET_RX_SUCCESS; 725 726 drop: 727 kfree_skb(skb); 728 return NET_RX_DROP; 729 } 730 731 static int canfd_rcv(struct sk_buff *skb, struct net_device *dev, 732 struct packet_type *pt, struct net_device *orig_dev) 733 { 734 struct canfd_frame *cfd = (struct canfd_frame *)skb->data; 735 736 if (unlikely(!net_eq(dev_net(dev), &init_net))) 737 goto drop; 738 739 if (WARN_ONCE(dev->type != ARPHRD_CAN || 740 skb->len != CANFD_MTU || 741 cfd->len > CANFD_MAX_DLEN, 742 "PF_CAN: dropped non conform CAN FD skbuf: " 743 "dev type %d, len %d, datalen %d\n", 744 dev->type, skb->len, cfd->len)) 745 goto drop; 746 747 can_receive(skb, dev); 748 return NET_RX_SUCCESS; 749 750 drop: 751 kfree_skb(skb); 752 return NET_RX_DROP; 753 } 754 755 /* 756 * af_can protocol functions 757 */ 758 759 /** 760 * can_proto_register - register CAN transport protocol 761 * @cp: pointer to CAN protocol structure 762 * 763 * Return: 764 * 0 on success 765 * -EINVAL invalid (out of range) protocol number 766 * -EBUSY protocol already in use 767 * -ENOBUF if proto_register() fails 768 */ 769 int can_proto_register(const struct can_proto *cp) 770 { 771 int proto = cp->protocol; 772 int err = 0; 773 774 if (proto < 0 || proto >= CAN_NPROTO) { 775 pr_err("can: protocol number %d out of range\n", proto); 776 return -EINVAL; 777 } 778 779 err = proto_register(cp->prot, 0); 780 if (err < 0) 781 return err; 782 783 mutex_lock(&proto_tab_lock); 784 785 if (proto_tab[proto]) { 786 pr_err("can: protocol %d already registered\n", proto); 787 err = -EBUSY; 788 } else 789 RCU_INIT_POINTER(proto_tab[proto], cp); 790 791 mutex_unlock(&proto_tab_lock); 792 793 if (err < 0) 794 proto_unregister(cp->prot); 795 796 return err; 797 } 798 EXPORT_SYMBOL(can_proto_register); 799 800 /** 801 * can_proto_unregister - unregister CAN transport protocol 802 * @cp: pointer to CAN protocol structure 803 */ 804 void can_proto_unregister(const struct can_proto *cp) 805 { 806 int proto = cp->protocol; 807 808 mutex_lock(&proto_tab_lock); 809 BUG_ON(proto_tab[proto] != cp); 810 RCU_INIT_POINTER(proto_tab[proto], NULL); 811 mutex_unlock(&proto_tab_lock); 812 813 synchronize_rcu(); 814 815 proto_unregister(cp->prot); 816 } 817 EXPORT_SYMBOL(can_proto_unregister); 818 819 /* 820 * af_can notifier to create/remove CAN netdevice specific structs 821 */ 822 static int can_notifier(struct notifier_block *nb, unsigned long msg, 823 void *ptr) 824 { 825 struct net_device *dev = netdev_notifier_info_to_dev(ptr); 826 struct dev_rcv_lists *d; 827 828 if (!net_eq(dev_net(dev), &init_net)) 829 return NOTIFY_DONE; 830 831 if (dev->type != ARPHRD_CAN) 832 return NOTIFY_DONE; 833 834 switch (msg) { 835 836 case NETDEV_REGISTER: 837 838 /* create new dev_rcv_lists for this device */ 839 d = kzalloc(sizeof(*d), GFP_KERNEL); 840 if (!d) 841 return NOTIFY_DONE; 842 BUG_ON(dev->ml_priv); 843 dev->ml_priv = d; 844 845 break; 846 847 case NETDEV_UNREGISTER: 848 spin_lock(&can_rcvlists_lock); 849 850 d = dev->ml_priv; 851 if (d) { 852 if (d->entries) 853 d->remove_on_zero_entries = 1; 854 else { 855 kfree(d); 856 dev->ml_priv = NULL; 857 } 858 } else 859 pr_err("can: notifier: receive list not found for dev " 860 "%s\n", dev->name); 861 862 spin_unlock(&can_rcvlists_lock); 863 864 break; 865 } 866 867 return NOTIFY_DONE; 868 } 869 870 /* 871 * af_can module init/exit functions 872 */ 873 874 static struct packet_type can_packet __read_mostly = { 875 .type = cpu_to_be16(ETH_P_CAN), 876 .func = can_rcv, 877 }; 878 879 static struct packet_type canfd_packet __read_mostly = { 880 .type = cpu_to_be16(ETH_P_CANFD), 881 .func = canfd_rcv, 882 }; 883 884 static const struct net_proto_family can_family_ops = { 885 .family = PF_CAN, 886 .create = can_create, 887 .owner = THIS_MODULE, 888 }; 889 890 /* notifier block for netdevice event */ 891 static struct notifier_block can_netdev_notifier __read_mostly = { 892 .notifier_call = can_notifier, 893 }; 894 895 static __init int can_init(void) 896 { 897 /* check for correct padding to be able to use the structs similarly */ 898 BUILD_BUG_ON(offsetof(struct can_frame, can_dlc) != 899 offsetof(struct canfd_frame, len) || 900 offsetof(struct can_frame, data) != 901 offsetof(struct canfd_frame, data)); 902 903 pr_info("can: controller area network core (" CAN_VERSION_STRING ")\n"); 904 905 memset(&can_rx_alldev_list, 0, sizeof(can_rx_alldev_list)); 906 907 rcv_cache = kmem_cache_create("can_receiver", sizeof(struct receiver), 908 0, 0, NULL); 909 if (!rcv_cache) 910 return -ENOMEM; 911 912 if (stats_timer) { 913 /* the statistics are updated every second (timer triggered) */ 914 setup_timer(&can_stattimer, can_stat_update, 0); 915 mod_timer(&can_stattimer, round_jiffies(jiffies + HZ)); 916 } else 917 can_stattimer.function = NULL; 918 919 can_init_proc(); 920 921 /* protocol register */ 922 sock_register(&can_family_ops); 923 register_netdevice_notifier(&can_netdev_notifier); 924 dev_add_pack(&can_packet); 925 dev_add_pack(&canfd_packet); 926 927 return 0; 928 } 929 930 static __exit void can_exit(void) 931 { 932 struct net_device *dev; 933 934 if (stats_timer) 935 del_timer_sync(&can_stattimer); 936 937 can_remove_proc(); 938 939 /* protocol unregister */ 940 dev_remove_pack(&canfd_packet); 941 dev_remove_pack(&can_packet); 942 unregister_netdevice_notifier(&can_netdev_notifier); 943 sock_unregister(PF_CAN); 944 945 /* remove created dev_rcv_lists from still registered CAN devices */ 946 rcu_read_lock(); 947 for_each_netdev_rcu(&init_net, dev) { 948 if (dev->type == ARPHRD_CAN && dev->ml_priv) { 949 950 struct dev_rcv_lists *d = dev->ml_priv; 951 952 BUG_ON(d->entries); 953 kfree(d); 954 dev->ml_priv = NULL; 955 } 956 } 957 rcu_read_unlock(); 958 959 rcu_barrier(); /* Wait for completion of call_rcu()'s */ 960 961 kmem_cache_destroy(rcv_cache); 962 } 963 964 module_init(can_init); 965 module_exit(can_exit); 966