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); 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_reset_network_header(skb); 263 skb_reset_transport_header(skb); 264 265 if (loop) { 266 /* local loopback of sent CAN frames */ 267 268 /* indication for the CAN driver: do loopback */ 269 skb->pkt_type = PACKET_LOOPBACK; 270 271 /* 272 * The reference to the originating sock may be required 273 * by the receiving socket to check whether the frame is 274 * its own. Example: can_raw sockopt CAN_RAW_RECV_OWN_MSGS 275 * Therefore we have to ensure that skb->sk remains the 276 * reference to the originating sock by restoring skb->sk 277 * after each skb_clone() or skb_orphan() usage. 278 */ 279 280 if (!(skb->dev->flags & IFF_ECHO)) { 281 /* 282 * If the interface is not capable to do loopback 283 * itself, we do it here. 284 */ 285 newskb = skb_clone(skb, GFP_ATOMIC); 286 if (!newskb) { 287 kfree_skb(skb); 288 return -ENOMEM; 289 } 290 291 can_skb_set_owner(newskb, skb->sk); 292 newskb->ip_summed = CHECKSUM_UNNECESSARY; 293 newskb->pkt_type = PACKET_BROADCAST; 294 } 295 } else { 296 /* indication for the CAN driver: no loopback required */ 297 skb->pkt_type = PACKET_HOST; 298 } 299 300 /* send to netdevice */ 301 err = dev_queue_xmit(skb); 302 if (err > 0) 303 err = net_xmit_errno(err); 304 305 if (err) { 306 kfree_skb(newskb); 307 return err; 308 } 309 310 if (newskb) 311 netif_rx_ni(newskb); 312 313 /* update statistics */ 314 can_stats.tx_frames++; 315 can_stats.tx_frames_delta++; 316 317 return 0; 318 319 inval_skb: 320 kfree_skb(skb); 321 return err; 322 } 323 EXPORT_SYMBOL(can_send); 324 325 /* 326 * af_can rx path 327 */ 328 329 static struct dev_rcv_lists *find_dev_rcv_lists(struct net_device *dev) 330 { 331 if (!dev) 332 return &can_rx_alldev_list; 333 else 334 return (struct dev_rcv_lists *)dev->ml_priv; 335 } 336 337 /** 338 * effhash - hash function for 29 bit CAN identifier reduction 339 * @can_id: 29 bit CAN identifier 340 * 341 * Description: 342 * To reduce the linear traversal in one linked list of _single_ EFF CAN 343 * frame subscriptions the 29 bit identifier is mapped to 10 bits. 344 * (see CAN_EFF_RCV_HASH_BITS definition) 345 * 346 * Return: 347 * Hash value from 0x000 - 0x3FF ( enforced by CAN_EFF_RCV_HASH_BITS mask ) 348 */ 349 static unsigned int effhash(canid_t can_id) 350 { 351 unsigned int hash; 352 353 hash = can_id; 354 hash ^= can_id >> CAN_EFF_RCV_HASH_BITS; 355 hash ^= can_id >> (2 * CAN_EFF_RCV_HASH_BITS); 356 357 return hash & ((1 << CAN_EFF_RCV_HASH_BITS) - 1); 358 } 359 360 /** 361 * find_rcv_list - determine optimal filterlist inside device filter struct 362 * @can_id: pointer to CAN identifier of a given can_filter 363 * @mask: pointer to CAN mask of a given can_filter 364 * @d: pointer to the device filter struct 365 * 366 * Description: 367 * Returns the optimal filterlist to reduce the filter handling in the 368 * receive path. This function is called by service functions that need 369 * to register or unregister a can_filter in the filter lists. 370 * 371 * A filter matches in general, when 372 * 373 * <received_can_id> & mask == can_id & mask 374 * 375 * so every bit set in the mask (even CAN_EFF_FLAG, CAN_RTR_FLAG) describe 376 * relevant bits for the filter. 377 * 378 * The filter can be inverted (CAN_INV_FILTER bit set in can_id) or it can 379 * filter for error messages (CAN_ERR_FLAG bit set in mask). For error msg 380 * frames there is a special filterlist and a special rx path filter handling. 381 * 382 * Return: 383 * Pointer to optimal filterlist for the given can_id/mask pair. 384 * Constistency checked mask. 385 * Reduced can_id to have a preprocessed filter compare value. 386 */ 387 static struct hlist_head *find_rcv_list(canid_t *can_id, canid_t *mask, 388 struct dev_rcv_lists *d) 389 { 390 canid_t inv = *can_id & CAN_INV_FILTER; /* save flag before masking */ 391 392 /* filter for error message frames in extra filterlist */ 393 if (*mask & CAN_ERR_FLAG) { 394 /* clear CAN_ERR_FLAG in filter entry */ 395 *mask &= CAN_ERR_MASK; 396 return &d->rx[RX_ERR]; 397 } 398 399 /* with cleared CAN_ERR_FLAG we have a simple mask/value filterpair */ 400 401 #define CAN_EFF_RTR_FLAGS (CAN_EFF_FLAG | CAN_RTR_FLAG) 402 403 /* ensure valid values in can_mask for 'SFF only' frame filtering */ 404 if ((*mask & CAN_EFF_FLAG) && !(*can_id & CAN_EFF_FLAG)) 405 *mask &= (CAN_SFF_MASK | CAN_EFF_RTR_FLAGS); 406 407 /* reduce condition testing at receive time */ 408 *can_id &= *mask; 409 410 /* inverse can_id/can_mask filter */ 411 if (inv) 412 return &d->rx[RX_INV]; 413 414 /* mask == 0 => no condition testing at receive time */ 415 if (!(*mask)) 416 return &d->rx[RX_ALL]; 417 418 /* extra filterlists for the subscription of a single non-RTR can_id */ 419 if (((*mask & CAN_EFF_RTR_FLAGS) == CAN_EFF_RTR_FLAGS) && 420 !(*can_id & CAN_RTR_FLAG)) { 421 422 if (*can_id & CAN_EFF_FLAG) { 423 if (*mask == (CAN_EFF_MASK | CAN_EFF_RTR_FLAGS)) 424 return &d->rx_eff[effhash(*can_id)]; 425 } else { 426 if (*mask == (CAN_SFF_MASK | CAN_EFF_RTR_FLAGS)) 427 return &d->rx_sff[*can_id]; 428 } 429 } 430 431 /* default: filter via can_id/can_mask */ 432 return &d->rx[RX_FIL]; 433 } 434 435 /** 436 * can_rx_register - subscribe CAN frames from a specific interface 437 * @dev: pointer to netdevice (NULL => subcribe from 'all' CAN devices list) 438 * @can_id: CAN identifier (see description) 439 * @mask: CAN mask (see description) 440 * @func: callback function on filter match 441 * @data: returned parameter for callback function 442 * @ident: string for calling module identification 443 * 444 * Description: 445 * Invokes the callback function with the received sk_buff and the given 446 * parameter 'data' on a matching receive filter. A filter matches, when 447 * 448 * <received_can_id> & mask == can_id & mask 449 * 450 * The filter can be inverted (CAN_INV_FILTER bit set in can_id) or it can 451 * filter for error message frames (CAN_ERR_FLAG bit set in mask). 452 * 453 * The provided pointer to the sk_buff is guaranteed to be valid as long as 454 * the callback function is running. The callback function must *not* free 455 * the given sk_buff while processing it's task. When the given sk_buff is 456 * needed after the end of the callback function it must be cloned inside 457 * the callback function with skb_clone(). 458 * 459 * Return: 460 * 0 on success 461 * -ENOMEM on missing cache mem to create subscription entry 462 * -ENODEV unknown device 463 */ 464 int can_rx_register(struct net_device *dev, canid_t can_id, canid_t mask, 465 void (*func)(struct sk_buff *, void *), void *data, 466 char *ident) 467 { 468 struct receiver *r; 469 struct hlist_head *rl; 470 struct dev_rcv_lists *d; 471 int err = 0; 472 473 /* insert new receiver (dev,canid,mask) -> (func,data) */ 474 475 if (dev && dev->type != ARPHRD_CAN) 476 return -ENODEV; 477 478 r = kmem_cache_alloc(rcv_cache, GFP_KERNEL); 479 if (!r) 480 return -ENOMEM; 481 482 spin_lock(&can_rcvlists_lock); 483 484 d = find_dev_rcv_lists(dev); 485 if (d) { 486 rl = find_rcv_list(&can_id, &mask, d); 487 488 r->can_id = can_id; 489 r->mask = mask; 490 r->matches = 0; 491 r->func = func; 492 r->data = data; 493 r->ident = ident; 494 495 hlist_add_head_rcu(&r->list, rl); 496 d->entries++; 497 498 can_pstats.rcv_entries++; 499 if (can_pstats.rcv_entries_max < can_pstats.rcv_entries) 500 can_pstats.rcv_entries_max = can_pstats.rcv_entries; 501 } else { 502 kmem_cache_free(rcv_cache, r); 503 err = -ENODEV; 504 } 505 506 spin_unlock(&can_rcvlists_lock); 507 508 return err; 509 } 510 EXPORT_SYMBOL(can_rx_register); 511 512 /* 513 * can_rx_delete_receiver - rcu callback for single receiver entry removal 514 */ 515 static void can_rx_delete_receiver(struct rcu_head *rp) 516 { 517 struct receiver *r = container_of(rp, struct receiver, rcu); 518 519 kmem_cache_free(rcv_cache, r); 520 } 521 522 /** 523 * can_rx_unregister - unsubscribe CAN frames from a specific interface 524 * @dev: pointer to netdevice (NULL => unsubscribe from 'all' CAN devices list) 525 * @can_id: CAN identifier 526 * @mask: CAN mask 527 * @func: callback function on filter match 528 * @data: returned parameter for callback function 529 * 530 * Description: 531 * Removes subscription entry depending on given (subscription) values. 532 */ 533 void can_rx_unregister(struct net_device *dev, canid_t can_id, canid_t mask, 534 void (*func)(struct sk_buff *, void *), void *data) 535 { 536 struct receiver *r = NULL; 537 struct hlist_head *rl; 538 struct dev_rcv_lists *d; 539 540 if (dev && dev->type != ARPHRD_CAN) 541 return; 542 543 spin_lock(&can_rcvlists_lock); 544 545 d = find_dev_rcv_lists(dev); 546 if (!d) { 547 pr_err("BUG: receive list not found for " 548 "dev %s, id %03X, mask %03X\n", 549 DNAME(dev), can_id, mask); 550 goto out; 551 } 552 553 rl = find_rcv_list(&can_id, &mask, d); 554 555 /* 556 * Search the receiver list for the item to delete. This should 557 * exist, since no receiver may be unregistered that hasn't 558 * been registered before. 559 */ 560 561 hlist_for_each_entry_rcu(r, rl, list) { 562 if (r->can_id == can_id && r->mask == mask && 563 r->func == func && r->data == data) 564 break; 565 } 566 567 /* 568 * Check for bugs in CAN protocol implementations using af_can.c: 569 * 'r' will be NULL if no matching list item was found for removal. 570 */ 571 572 if (!r) { 573 WARN(1, "BUG: receive list entry not found for dev %s, " 574 "id %03X, mask %03X\n", DNAME(dev), can_id, mask); 575 goto out; 576 } 577 578 hlist_del_rcu(&r->list); 579 d->entries--; 580 581 if (can_pstats.rcv_entries > 0) 582 can_pstats.rcv_entries--; 583 584 /* remove device structure requested by NETDEV_UNREGISTER */ 585 if (d->remove_on_zero_entries && !d->entries) { 586 kfree(d); 587 dev->ml_priv = NULL; 588 } 589 590 out: 591 spin_unlock(&can_rcvlists_lock); 592 593 /* schedule the receiver item for deletion */ 594 if (r) 595 call_rcu(&r->rcu, can_rx_delete_receiver); 596 } 597 EXPORT_SYMBOL(can_rx_unregister); 598 599 static inline void deliver(struct sk_buff *skb, struct receiver *r) 600 { 601 r->func(skb, r->data); 602 r->matches++; 603 } 604 605 static int can_rcv_filter(struct dev_rcv_lists *d, struct sk_buff *skb) 606 { 607 struct receiver *r; 608 int matches = 0; 609 struct can_frame *cf = (struct can_frame *)skb->data; 610 canid_t can_id = cf->can_id; 611 612 if (d->entries == 0) 613 return 0; 614 615 if (can_id & CAN_ERR_FLAG) { 616 /* check for error message frame entries only */ 617 hlist_for_each_entry_rcu(r, &d->rx[RX_ERR], list) { 618 if (can_id & r->mask) { 619 deliver(skb, r); 620 matches++; 621 } 622 } 623 return matches; 624 } 625 626 /* check for unfiltered entries */ 627 hlist_for_each_entry_rcu(r, &d->rx[RX_ALL], list) { 628 deliver(skb, r); 629 matches++; 630 } 631 632 /* check for can_id/mask entries */ 633 hlist_for_each_entry_rcu(r, &d->rx[RX_FIL], list) { 634 if ((can_id & r->mask) == r->can_id) { 635 deliver(skb, r); 636 matches++; 637 } 638 } 639 640 /* check for inverted can_id/mask entries */ 641 hlist_for_each_entry_rcu(r, &d->rx[RX_INV], list) { 642 if ((can_id & r->mask) != r->can_id) { 643 deliver(skb, r); 644 matches++; 645 } 646 } 647 648 /* check filterlists for single non-RTR can_ids */ 649 if (can_id & CAN_RTR_FLAG) 650 return matches; 651 652 if (can_id & CAN_EFF_FLAG) { 653 hlist_for_each_entry_rcu(r, &d->rx_eff[effhash(can_id)], list) { 654 if (r->can_id == can_id) { 655 deliver(skb, r); 656 matches++; 657 } 658 } 659 } else { 660 can_id &= CAN_SFF_MASK; 661 hlist_for_each_entry_rcu(r, &d->rx_sff[can_id], list) { 662 deliver(skb, r); 663 matches++; 664 } 665 } 666 667 return matches; 668 } 669 670 static void can_receive(struct sk_buff *skb, struct net_device *dev) 671 { 672 struct dev_rcv_lists *d; 673 int matches; 674 675 /* update statistics */ 676 can_stats.rx_frames++; 677 can_stats.rx_frames_delta++; 678 679 rcu_read_lock(); 680 681 /* deliver the packet to sockets listening on all devices */ 682 matches = can_rcv_filter(&can_rx_alldev_list, skb); 683 684 /* find receive list for this device */ 685 d = find_dev_rcv_lists(dev); 686 if (d) 687 matches += can_rcv_filter(d, skb); 688 689 rcu_read_unlock(); 690 691 /* consume the skbuff allocated by the netdevice driver */ 692 consume_skb(skb); 693 694 if (matches > 0) { 695 can_stats.matches++; 696 can_stats.matches_delta++; 697 } 698 } 699 700 static int can_rcv(struct sk_buff *skb, struct net_device *dev, 701 struct packet_type *pt, struct net_device *orig_dev) 702 { 703 struct canfd_frame *cfd = (struct canfd_frame *)skb->data; 704 705 if (unlikely(!net_eq(dev_net(dev), &init_net))) 706 goto drop; 707 708 if (WARN_ONCE(dev->type != ARPHRD_CAN || 709 skb->len != CAN_MTU || 710 cfd->len > CAN_MAX_DLEN, 711 "PF_CAN: dropped non conform CAN skbuf: " 712 "dev type %d, len %d, datalen %d\n", 713 dev->type, skb->len, cfd->len)) 714 goto drop; 715 716 can_receive(skb, dev); 717 return NET_RX_SUCCESS; 718 719 drop: 720 kfree_skb(skb); 721 return NET_RX_DROP; 722 } 723 724 static int canfd_rcv(struct sk_buff *skb, struct net_device *dev, 725 struct packet_type *pt, struct net_device *orig_dev) 726 { 727 struct canfd_frame *cfd = (struct canfd_frame *)skb->data; 728 729 if (unlikely(!net_eq(dev_net(dev), &init_net))) 730 goto drop; 731 732 if (WARN_ONCE(dev->type != ARPHRD_CAN || 733 skb->len != CANFD_MTU || 734 cfd->len > CANFD_MAX_DLEN, 735 "PF_CAN: dropped non conform CAN FD skbuf: " 736 "dev type %d, len %d, datalen %d\n", 737 dev->type, skb->len, cfd->len)) 738 goto drop; 739 740 can_receive(skb, dev); 741 return NET_RX_SUCCESS; 742 743 drop: 744 kfree_skb(skb); 745 return NET_RX_DROP; 746 } 747 748 /* 749 * af_can protocol functions 750 */ 751 752 /** 753 * can_proto_register - register CAN transport protocol 754 * @cp: pointer to CAN protocol structure 755 * 756 * Return: 757 * 0 on success 758 * -EINVAL invalid (out of range) protocol number 759 * -EBUSY protocol already in use 760 * -ENOBUF if proto_register() fails 761 */ 762 int can_proto_register(const struct can_proto *cp) 763 { 764 int proto = cp->protocol; 765 int err = 0; 766 767 if (proto < 0 || proto >= CAN_NPROTO) { 768 pr_err("can: protocol number %d out of range\n", proto); 769 return -EINVAL; 770 } 771 772 err = proto_register(cp->prot, 0); 773 if (err < 0) 774 return err; 775 776 mutex_lock(&proto_tab_lock); 777 778 if (proto_tab[proto]) { 779 pr_err("can: protocol %d already registered\n", proto); 780 err = -EBUSY; 781 } else 782 RCU_INIT_POINTER(proto_tab[proto], cp); 783 784 mutex_unlock(&proto_tab_lock); 785 786 if (err < 0) 787 proto_unregister(cp->prot); 788 789 return err; 790 } 791 EXPORT_SYMBOL(can_proto_register); 792 793 /** 794 * can_proto_unregister - unregister CAN transport protocol 795 * @cp: pointer to CAN protocol structure 796 */ 797 void can_proto_unregister(const struct can_proto *cp) 798 { 799 int proto = cp->protocol; 800 801 mutex_lock(&proto_tab_lock); 802 BUG_ON(proto_tab[proto] != cp); 803 RCU_INIT_POINTER(proto_tab[proto], NULL); 804 mutex_unlock(&proto_tab_lock); 805 806 synchronize_rcu(); 807 808 proto_unregister(cp->prot); 809 } 810 EXPORT_SYMBOL(can_proto_unregister); 811 812 /* 813 * af_can notifier to create/remove CAN netdevice specific structs 814 */ 815 static int can_notifier(struct notifier_block *nb, unsigned long msg, 816 void *ptr) 817 { 818 struct net_device *dev = netdev_notifier_info_to_dev(ptr); 819 struct dev_rcv_lists *d; 820 821 if (!net_eq(dev_net(dev), &init_net)) 822 return NOTIFY_DONE; 823 824 if (dev->type != ARPHRD_CAN) 825 return NOTIFY_DONE; 826 827 switch (msg) { 828 829 case NETDEV_REGISTER: 830 831 /* create new dev_rcv_lists for this device */ 832 d = kzalloc(sizeof(*d), GFP_KERNEL); 833 if (!d) 834 return NOTIFY_DONE; 835 BUG_ON(dev->ml_priv); 836 dev->ml_priv = d; 837 838 break; 839 840 case NETDEV_UNREGISTER: 841 spin_lock(&can_rcvlists_lock); 842 843 d = dev->ml_priv; 844 if (d) { 845 if (d->entries) 846 d->remove_on_zero_entries = 1; 847 else { 848 kfree(d); 849 dev->ml_priv = NULL; 850 } 851 } else 852 pr_err("can: notifier: receive list not found for dev " 853 "%s\n", dev->name); 854 855 spin_unlock(&can_rcvlists_lock); 856 857 break; 858 } 859 860 return NOTIFY_DONE; 861 } 862 863 /* 864 * af_can module init/exit functions 865 */ 866 867 static struct packet_type can_packet __read_mostly = { 868 .type = cpu_to_be16(ETH_P_CAN), 869 .func = can_rcv, 870 }; 871 872 static struct packet_type canfd_packet __read_mostly = { 873 .type = cpu_to_be16(ETH_P_CANFD), 874 .func = canfd_rcv, 875 }; 876 877 static const struct net_proto_family can_family_ops = { 878 .family = PF_CAN, 879 .create = can_create, 880 .owner = THIS_MODULE, 881 }; 882 883 /* notifier block for netdevice event */ 884 static struct notifier_block can_netdev_notifier __read_mostly = { 885 .notifier_call = can_notifier, 886 }; 887 888 static __init int can_init(void) 889 { 890 /* check for correct padding to be able to use the structs similarly */ 891 BUILD_BUG_ON(offsetof(struct can_frame, can_dlc) != 892 offsetof(struct canfd_frame, len) || 893 offsetof(struct can_frame, data) != 894 offsetof(struct canfd_frame, data)); 895 896 pr_info("can: controller area network core (" CAN_VERSION_STRING ")\n"); 897 898 memset(&can_rx_alldev_list, 0, sizeof(can_rx_alldev_list)); 899 900 rcv_cache = kmem_cache_create("can_receiver", sizeof(struct receiver), 901 0, 0, NULL); 902 if (!rcv_cache) 903 return -ENOMEM; 904 905 if (stats_timer) { 906 /* the statistics are updated every second (timer triggered) */ 907 setup_timer(&can_stattimer, can_stat_update, 0); 908 mod_timer(&can_stattimer, round_jiffies(jiffies + HZ)); 909 } else 910 can_stattimer.function = NULL; 911 912 can_init_proc(); 913 914 /* protocol register */ 915 sock_register(&can_family_ops); 916 register_netdevice_notifier(&can_netdev_notifier); 917 dev_add_pack(&can_packet); 918 dev_add_pack(&canfd_packet); 919 920 return 0; 921 } 922 923 static __exit void can_exit(void) 924 { 925 struct net_device *dev; 926 927 if (stats_timer) 928 del_timer_sync(&can_stattimer); 929 930 can_remove_proc(); 931 932 /* protocol unregister */ 933 dev_remove_pack(&canfd_packet); 934 dev_remove_pack(&can_packet); 935 unregister_netdevice_notifier(&can_netdev_notifier); 936 sock_unregister(PF_CAN); 937 938 /* remove created dev_rcv_lists from still registered CAN devices */ 939 rcu_read_lock(); 940 for_each_netdev_rcu(&init_net, dev) { 941 if (dev->type == ARPHRD_CAN && dev->ml_priv) { 942 943 struct dev_rcv_lists *d = dev->ml_priv; 944 945 BUG_ON(d->entries); 946 kfree(d); 947 dev->ml_priv = NULL; 948 } 949 } 950 rcu_read_unlock(); 951 952 rcu_barrier(); /* Wait for completion of call_rcu()'s */ 953 954 kmem_cache_destroy(rcv_cache); 955 } 956 957 module_init(can_init); 958 module_exit(can_exit); 959