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 static atomic_t skbcounter = ATOMIC_INIT(0); 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, kern); 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->ip_summed = CHECKSUM_UNNECESSARY; 265 266 skb_reset_mac_header(skb); 267 skb_reset_network_header(skb); 268 skb_reset_transport_header(skb); 269 270 if (loop) { 271 /* local loopback of sent CAN frames */ 272 273 /* indication for the CAN driver: do loopback */ 274 skb->pkt_type = PACKET_LOOPBACK; 275 276 /* 277 * The reference to the originating sock may be required 278 * by the receiving socket to check whether the frame is 279 * its own. Example: can_raw sockopt CAN_RAW_RECV_OWN_MSGS 280 * Therefore we have to ensure that skb->sk remains the 281 * reference to the originating sock by restoring skb->sk 282 * after each skb_clone() or skb_orphan() usage. 283 */ 284 285 if (!(skb->dev->flags & IFF_ECHO)) { 286 /* 287 * If the interface is not capable to do loopback 288 * itself, we do it here. 289 */ 290 newskb = skb_clone(skb, GFP_ATOMIC); 291 if (!newskb) { 292 kfree_skb(skb); 293 return -ENOMEM; 294 } 295 296 can_skb_set_owner(newskb, skb->sk); 297 newskb->ip_summed = CHECKSUM_UNNECESSARY; 298 newskb->pkt_type = PACKET_BROADCAST; 299 } 300 } else { 301 /* indication for the CAN driver: no loopback required */ 302 skb->pkt_type = PACKET_HOST; 303 } 304 305 /* send to netdevice */ 306 err = dev_queue_xmit(skb); 307 if (err > 0) 308 err = net_xmit_errno(err); 309 310 if (err) { 311 kfree_skb(newskb); 312 return err; 313 } 314 315 if (newskb) 316 netif_rx_ni(newskb); 317 318 /* update statistics */ 319 can_stats.tx_frames++; 320 can_stats.tx_frames_delta++; 321 322 return 0; 323 324 inval_skb: 325 kfree_skb(skb); 326 return err; 327 } 328 EXPORT_SYMBOL(can_send); 329 330 /* 331 * af_can rx path 332 */ 333 334 static struct dev_rcv_lists *find_dev_rcv_lists(struct net_device *dev) 335 { 336 if (!dev) 337 return &can_rx_alldev_list; 338 else 339 return (struct dev_rcv_lists *)dev->ml_priv; 340 } 341 342 /** 343 * effhash - hash function for 29 bit CAN identifier reduction 344 * @can_id: 29 bit CAN identifier 345 * 346 * Description: 347 * To reduce the linear traversal in one linked list of _single_ EFF CAN 348 * frame subscriptions the 29 bit identifier is mapped to 10 bits. 349 * (see CAN_EFF_RCV_HASH_BITS definition) 350 * 351 * Return: 352 * Hash value from 0x000 - 0x3FF ( enforced by CAN_EFF_RCV_HASH_BITS mask ) 353 */ 354 static unsigned int effhash(canid_t can_id) 355 { 356 unsigned int hash; 357 358 hash = can_id; 359 hash ^= can_id >> CAN_EFF_RCV_HASH_BITS; 360 hash ^= can_id >> (2 * CAN_EFF_RCV_HASH_BITS); 361 362 return hash & ((1 << CAN_EFF_RCV_HASH_BITS) - 1); 363 } 364 365 /** 366 * find_rcv_list - determine optimal filterlist inside device filter struct 367 * @can_id: pointer to CAN identifier of a given can_filter 368 * @mask: pointer to CAN mask of a given can_filter 369 * @d: pointer to the device filter struct 370 * 371 * Description: 372 * Returns the optimal filterlist to reduce the filter handling in the 373 * receive path. This function is called by service functions that need 374 * to register or unregister a can_filter in the filter lists. 375 * 376 * A filter matches in general, when 377 * 378 * <received_can_id> & mask == can_id & mask 379 * 380 * so every bit set in the mask (even CAN_EFF_FLAG, CAN_RTR_FLAG) describe 381 * relevant bits for the filter. 382 * 383 * The filter can be inverted (CAN_INV_FILTER bit set in can_id) or it can 384 * filter for error messages (CAN_ERR_FLAG bit set in mask). For error msg 385 * frames there is a special filterlist and a special rx path filter handling. 386 * 387 * Return: 388 * Pointer to optimal filterlist for the given can_id/mask pair. 389 * Constistency checked mask. 390 * Reduced can_id to have a preprocessed filter compare value. 391 */ 392 static struct hlist_head *find_rcv_list(canid_t *can_id, canid_t *mask, 393 struct dev_rcv_lists *d) 394 { 395 canid_t inv = *can_id & CAN_INV_FILTER; /* save flag before masking */ 396 397 /* filter for error message frames in extra filterlist */ 398 if (*mask & CAN_ERR_FLAG) { 399 /* clear CAN_ERR_FLAG in filter entry */ 400 *mask &= CAN_ERR_MASK; 401 return &d->rx[RX_ERR]; 402 } 403 404 /* with cleared CAN_ERR_FLAG we have a simple mask/value filterpair */ 405 406 #define CAN_EFF_RTR_FLAGS (CAN_EFF_FLAG | CAN_RTR_FLAG) 407 408 /* ensure valid values in can_mask for 'SFF only' frame filtering */ 409 if ((*mask & CAN_EFF_FLAG) && !(*can_id & CAN_EFF_FLAG)) 410 *mask &= (CAN_SFF_MASK | CAN_EFF_RTR_FLAGS); 411 412 /* reduce condition testing at receive time */ 413 *can_id &= *mask; 414 415 /* inverse can_id/can_mask filter */ 416 if (inv) 417 return &d->rx[RX_INV]; 418 419 /* mask == 0 => no condition testing at receive time */ 420 if (!(*mask)) 421 return &d->rx[RX_ALL]; 422 423 /* extra filterlists for the subscription of a single non-RTR can_id */ 424 if (((*mask & CAN_EFF_RTR_FLAGS) == CAN_EFF_RTR_FLAGS) && 425 !(*can_id & CAN_RTR_FLAG)) { 426 427 if (*can_id & CAN_EFF_FLAG) { 428 if (*mask == (CAN_EFF_MASK | CAN_EFF_RTR_FLAGS)) 429 return &d->rx_eff[effhash(*can_id)]; 430 } else { 431 if (*mask == (CAN_SFF_MASK | CAN_EFF_RTR_FLAGS)) 432 return &d->rx_sff[*can_id]; 433 } 434 } 435 436 /* default: filter via can_id/can_mask */ 437 return &d->rx[RX_FIL]; 438 } 439 440 /** 441 * can_rx_register - subscribe CAN frames from a specific interface 442 * @dev: pointer to netdevice (NULL => subcribe from 'all' CAN devices list) 443 * @can_id: CAN identifier (see description) 444 * @mask: CAN mask (see description) 445 * @func: callback function on filter match 446 * @data: returned parameter for callback function 447 * @ident: string for calling module identification 448 * 449 * Description: 450 * Invokes the callback function with the received sk_buff and the given 451 * parameter 'data' on a matching receive filter. A filter matches, when 452 * 453 * <received_can_id> & mask == can_id & mask 454 * 455 * The filter can be inverted (CAN_INV_FILTER bit set in can_id) or it can 456 * filter for error message frames (CAN_ERR_FLAG bit set in mask). 457 * 458 * The provided pointer to the sk_buff is guaranteed to be valid as long as 459 * the callback function is running. The callback function must *not* free 460 * the given sk_buff while processing it's task. When the given sk_buff is 461 * needed after the end of the callback function it must be cloned inside 462 * the callback function with skb_clone(). 463 * 464 * Return: 465 * 0 on success 466 * -ENOMEM on missing cache mem to create subscription entry 467 * -ENODEV unknown device 468 */ 469 int can_rx_register(struct net_device *dev, canid_t can_id, canid_t mask, 470 void (*func)(struct sk_buff *, void *), void *data, 471 char *ident) 472 { 473 struct receiver *r; 474 struct hlist_head *rl; 475 struct dev_rcv_lists *d; 476 int err = 0; 477 478 /* insert new receiver (dev,canid,mask) -> (func,data) */ 479 480 if (dev && dev->type != ARPHRD_CAN) 481 return -ENODEV; 482 483 r = kmem_cache_alloc(rcv_cache, GFP_KERNEL); 484 if (!r) 485 return -ENOMEM; 486 487 spin_lock(&can_rcvlists_lock); 488 489 d = find_dev_rcv_lists(dev); 490 if (d) { 491 rl = find_rcv_list(&can_id, &mask, d); 492 493 r->can_id = can_id; 494 r->mask = mask; 495 r->matches = 0; 496 r->func = func; 497 r->data = data; 498 r->ident = ident; 499 500 hlist_add_head_rcu(&r->list, rl); 501 d->entries++; 502 503 can_pstats.rcv_entries++; 504 if (can_pstats.rcv_entries_max < can_pstats.rcv_entries) 505 can_pstats.rcv_entries_max = can_pstats.rcv_entries; 506 } else { 507 kmem_cache_free(rcv_cache, r); 508 err = -ENODEV; 509 } 510 511 spin_unlock(&can_rcvlists_lock); 512 513 return err; 514 } 515 EXPORT_SYMBOL(can_rx_register); 516 517 /* 518 * can_rx_delete_receiver - rcu callback for single receiver entry removal 519 */ 520 static void can_rx_delete_receiver(struct rcu_head *rp) 521 { 522 struct receiver *r = container_of(rp, struct receiver, rcu); 523 524 kmem_cache_free(rcv_cache, r); 525 } 526 527 /** 528 * can_rx_unregister - unsubscribe CAN frames from a specific interface 529 * @dev: pointer to netdevice (NULL => unsubscribe from 'all' CAN devices list) 530 * @can_id: CAN identifier 531 * @mask: CAN mask 532 * @func: callback function on filter match 533 * @data: returned parameter for callback function 534 * 535 * Description: 536 * Removes subscription entry depending on given (subscription) values. 537 */ 538 void can_rx_unregister(struct net_device *dev, canid_t can_id, canid_t mask, 539 void (*func)(struct sk_buff *, void *), void *data) 540 { 541 struct receiver *r = NULL; 542 struct hlist_head *rl; 543 struct dev_rcv_lists *d; 544 545 if (dev && dev->type != ARPHRD_CAN) 546 return; 547 548 spin_lock(&can_rcvlists_lock); 549 550 d = find_dev_rcv_lists(dev); 551 if (!d) { 552 pr_err("BUG: receive list not found for " 553 "dev %s, id %03X, mask %03X\n", 554 DNAME(dev), can_id, mask); 555 goto out; 556 } 557 558 rl = find_rcv_list(&can_id, &mask, d); 559 560 /* 561 * Search the receiver list for the item to delete. This should 562 * exist, since no receiver may be unregistered that hasn't 563 * been registered before. 564 */ 565 566 hlist_for_each_entry_rcu(r, rl, list) { 567 if (r->can_id == can_id && r->mask == mask && 568 r->func == func && r->data == data) 569 break; 570 } 571 572 /* 573 * Check for bugs in CAN protocol implementations using af_can.c: 574 * 'r' will be NULL if no matching list item was found for removal. 575 */ 576 577 if (!r) { 578 WARN(1, "BUG: receive list entry not found for dev %s, " 579 "id %03X, mask %03X\n", DNAME(dev), can_id, mask); 580 goto out; 581 } 582 583 hlist_del_rcu(&r->list); 584 d->entries--; 585 586 if (can_pstats.rcv_entries > 0) 587 can_pstats.rcv_entries--; 588 589 /* remove device structure requested by NETDEV_UNREGISTER */ 590 if (d->remove_on_zero_entries && !d->entries) { 591 kfree(d); 592 dev->ml_priv = NULL; 593 } 594 595 out: 596 spin_unlock(&can_rcvlists_lock); 597 598 /* schedule the receiver item for deletion */ 599 if (r) 600 call_rcu(&r->rcu, can_rx_delete_receiver); 601 } 602 EXPORT_SYMBOL(can_rx_unregister); 603 604 static inline void deliver(struct sk_buff *skb, struct receiver *r) 605 { 606 r->func(skb, r->data); 607 r->matches++; 608 } 609 610 static int can_rcv_filter(struct dev_rcv_lists *d, struct sk_buff *skb) 611 { 612 struct receiver *r; 613 int matches = 0; 614 struct can_frame *cf = (struct can_frame *)skb->data; 615 canid_t can_id = cf->can_id; 616 617 if (d->entries == 0) 618 return 0; 619 620 if (can_id & CAN_ERR_FLAG) { 621 /* check for error message frame entries only */ 622 hlist_for_each_entry_rcu(r, &d->rx[RX_ERR], list) { 623 if (can_id & r->mask) { 624 deliver(skb, r); 625 matches++; 626 } 627 } 628 return matches; 629 } 630 631 /* check for unfiltered entries */ 632 hlist_for_each_entry_rcu(r, &d->rx[RX_ALL], list) { 633 deliver(skb, r); 634 matches++; 635 } 636 637 /* check for can_id/mask entries */ 638 hlist_for_each_entry_rcu(r, &d->rx[RX_FIL], list) { 639 if ((can_id & r->mask) == r->can_id) { 640 deliver(skb, r); 641 matches++; 642 } 643 } 644 645 /* check for inverted can_id/mask entries */ 646 hlist_for_each_entry_rcu(r, &d->rx[RX_INV], list) { 647 if ((can_id & r->mask) != r->can_id) { 648 deliver(skb, r); 649 matches++; 650 } 651 } 652 653 /* check filterlists for single non-RTR can_ids */ 654 if (can_id & CAN_RTR_FLAG) 655 return matches; 656 657 if (can_id & CAN_EFF_FLAG) { 658 hlist_for_each_entry_rcu(r, &d->rx_eff[effhash(can_id)], list) { 659 if (r->can_id == can_id) { 660 deliver(skb, r); 661 matches++; 662 } 663 } 664 } else { 665 can_id &= CAN_SFF_MASK; 666 hlist_for_each_entry_rcu(r, &d->rx_sff[can_id], list) { 667 deliver(skb, r); 668 matches++; 669 } 670 } 671 672 return matches; 673 } 674 675 static void can_receive(struct sk_buff *skb, struct net_device *dev) 676 { 677 struct dev_rcv_lists *d; 678 int matches; 679 680 /* update statistics */ 681 can_stats.rx_frames++; 682 can_stats.rx_frames_delta++; 683 684 /* create non-zero unique skb identifier together with *skb */ 685 while (!(can_skb_prv(skb)->skbcnt)) 686 can_skb_prv(skb)->skbcnt = atomic_inc_return(&skbcounter); 687 688 rcu_read_lock(); 689 690 /* deliver the packet to sockets listening on all devices */ 691 matches = can_rcv_filter(&can_rx_alldev_list, skb); 692 693 /* find receive list for this device */ 694 d = find_dev_rcv_lists(dev); 695 if (d) 696 matches += can_rcv_filter(d, skb); 697 698 rcu_read_unlock(); 699 700 /* consume the skbuff allocated by the netdevice driver */ 701 consume_skb(skb); 702 703 if (matches > 0) { 704 can_stats.matches++; 705 can_stats.matches_delta++; 706 } 707 } 708 709 static int can_rcv(struct sk_buff *skb, struct net_device *dev, 710 struct packet_type *pt, struct net_device *orig_dev) 711 { 712 struct canfd_frame *cfd = (struct canfd_frame *)skb->data; 713 714 if (unlikely(!net_eq(dev_net(dev), &init_net))) 715 goto drop; 716 717 if (WARN_ONCE(dev->type != ARPHRD_CAN || 718 skb->len != CAN_MTU || 719 cfd->len > CAN_MAX_DLEN, 720 "PF_CAN: dropped non conform CAN skbuf: " 721 "dev type %d, len %d, datalen %d\n", 722 dev->type, skb->len, cfd->len)) 723 goto drop; 724 725 can_receive(skb, dev); 726 return NET_RX_SUCCESS; 727 728 drop: 729 kfree_skb(skb); 730 return NET_RX_DROP; 731 } 732 733 static int canfd_rcv(struct sk_buff *skb, struct net_device *dev, 734 struct packet_type *pt, struct net_device *orig_dev) 735 { 736 struct canfd_frame *cfd = (struct canfd_frame *)skb->data; 737 738 if (unlikely(!net_eq(dev_net(dev), &init_net))) 739 goto drop; 740 741 if (WARN_ONCE(dev->type != ARPHRD_CAN || 742 skb->len != CANFD_MTU || 743 cfd->len > CANFD_MAX_DLEN, 744 "PF_CAN: dropped non conform CAN FD skbuf: " 745 "dev type %d, len %d, datalen %d\n", 746 dev->type, skb->len, cfd->len)) 747 goto drop; 748 749 can_receive(skb, dev); 750 return NET_RX_SUCCESS; 751 752 drop: 753 kfree_skb(skb); 754 return NET_RX_DROP; 755 } 756 757 /* 758 * af_can protocol functions 759 */ 760 761 /** 762 * can_proto_register - register CAN transport protocol 763 * @cp: pointer to CAN protocol structure 764 * 765 * Return: 766 * 0 on success 767 * -EINVAL invalid (out of range) protocol number 768 * -EBUSY protocol already in use 769 * -ENOBUF if proto_register() fails 770 */ 771 int can_proto_register(const struct can_proto *cp) 772 { 773 int proto = cp->protocol; 774 int err = 0; 775 776 if (proto < 0 || proto >= CAN_NPROTO) { 777 pr_err("can: protocol number %d out of range\n", proto); 778 return -EINVAL; 779 } 780 781 err = proto_register(cp->prot, 0); 782 if (err < 0) 783 return err; 784 785 mutex_lock(&proto_tab_lock); 786 787 if (proto_tab[proto]) { 788 pr_err("can: protocol %d already registered\n", proto); 789 err = -EBUSY; 790 } else 791 RCU_INIT_POINTER(proto_tab[proto], cp); 792 793 mutex_unlock(&proto_tab_lock); 794 795 if (err < 0) 796 proto_unregister(cp->prot); 797 798 return err; 799 } 800 EXPORT_SYMBOL(can_proto_register); 801 802 /** 803 * can_proto_unregister - unregister CAN transport protocol 804 * @cp: pointer to CAN protocol structure 805 */ 806 void can_proto_unregister(const struct can_proto *cp) 807 { 808 int proto = cp->protocol; 809 810 mutex_lock(&proto_tab_lock); 811 BUG_ON(proto_tab[proto] != cp); 812 RCU_INIT_POINTER(proto_tab[proto], NULL); 813 mutex_unlock(&proto_tab_lock); 814 815 synchronize_rcu(); 816 817 proto_unregister(cp->prot); 818 } 819 EXPORT_SYMBOL(can_proto_unregister); 820 821 /* 822 * af_can notifier to create/remove CAN netdevice specific structs 823 */ 824 static int can_notifier(struct notifier_block *nb, unsigned long msg, 825 void *ptr) 826 { 827 struct net_device *dev = netdev_notifier_info_to_dev(ptr); 828 struct dev_rcv_lists *d; 829 830 if (!net_eq(dev_net(dev), &init_net)) 831 return NOTIFY_DONE; 832 833 if (dev->type != ARPHRD_CAN) 834 return NOTIFY_DONE; 835 836 switch (msg) { 837 838 case NETDEV_REGISTER: 839 840 /* create new dev_rcv_lists for this device */ 841 d = kzalloc(sizeof(*d), GFP_KERNEL); 842 if (!d) 843 return NOTIFY_DONE; 844 BUG_ON(dev->ml_priv); 845 dev->ml_priv = d; 846 847 break; 848 849 case NETDEV_UNREGISTER: 850 spin_lock(&can_rcvlists_lock); 851 852 d = dev->ml_priv; 853 if (d) { 854 if (d->entries) 855 d->remove_on_zero_entries = 1; 856 else { 857 kfree(d); 858 dev->ml_priv = NULL; 859 } 860 } else 861 pr_err("can: notifier: receive list not found for dev " 862 "%s\n", dev->name); 863 864 spin_unlock(&can_rcvlists_lock); 865 866 break; 867 } 868 869 return NOTIFY_DONE; 870 } 871 872 /* 873 * af_can module init/exit functions 874 */ 875 876 static struct packet_type can_packet __read_mostly = { 877 .type = cpu_to_be16(ETH_P_CAN), 878 .func = can_rcv, 879 }; 880 881 static struct packet_type canfd_packet __read_mostly = { 882 .type = cpu_to_be16(ETH_P_CANFD), 883 .func = canfd_rcv, 884 }; 885 886 static const struct net_proto_family can_family_ops = { 887 .family = PF_CAN, 888 .create = can_create, 889 .owner = THIS_MODULE, 890 }; 891 892 /* notifier block for netdevice event */ 893 static struct notifier_block can_netdev_notifier __read_mostly = { 894 .notifier_call = can_notifier, 895 }; 896 897 static __init int can_init(void) 898 { 899 /* check for correct padding to be able to use the structs similarly */ 900 BUILD_BUG_ON(offsetof(struct can_frame, can_dlc) != 901 offsetof(struct canfd_frame, len) || 902 offsetof(struct can_frame, data) != 903 offsetof(struct canfd_frame, data)); 904 905 pr_info("can: controller area network core (" CAN_VERSION_STRING ")\n"); 906 907 memset(&can_rx_alldev_list, 0, sizeof(can_rx_alldev_list)); 908 909 rcv_cache = kmem_cache_create("can_receiver", sizeof(struct receiver), 910 0, 0, NULL); 911 if (!rcv_cache) 912 return -ENOMEM; 913 914 if (stats_timer) { 915 /* the statistics are updated every second (timer triggered) */ 916 setup_timer(&can_stattimer, can_stat_update, 0); 917 mod_timer(&can_stattimer, round_jiffies(jiffies + HZ)); 918 } else 919 can_stattimer.function = NULL; 920 921 can_init_proc(); 922 923 /* protocol register */ 924 sock_register(&can_family_ops); 925 register_netdevice_notifier(&can_netdev_notifier); 926 dev_add_pack(&can_packet); 927 dev_add_pack(&canfd_packet); 928 929 return 0; 930 } 931 932 static __exit void can_exit(void) 933 { 934 struct net_device *dev; 935 936 if (stats_timer) 937 del_timer_sync(&can_stattimer); 938 939 can_remove_proc(); 940 941 /* protocol unregister */ 942 dev_remove_pack(&canfd_packet); 943 dev_remove_pack(&can_packet); 944 unregister_netdevice_notifier(&can_netdev_notifier); 945 sock_unregister(PF_CAN); 946 947 /* remove created dev_rcv_lists from still registered CAN devices */ 948 rcu_read_lock(); 949 for_each_netdev_rcu(&init_net, dev) { 950 if (dev->type == ARPHRD_CAN && dev->ml_priv) { 951 952 struct dev_rcv_lists *d = dev->ml_priv; 953 954 BUG_ON(d->entries); 955 kfree(d); 956 dev->ml_priv = NULL; 957 } 958 } 959 rcu_read_unlock(); 960 961 rcu_barrier(); /* Wait for completion of call_rcu()'s */ 962 963 kmem_cache_destroy(rcv_cache); 964 } 965 966 module_init(can_init); 967 module_exit(can_exit); 968