1 // SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause) 2 /* af_can.c - Protocol family CAN core module 3 * (used by different CAN protocol modules) 4 * 5 * Copyright (c) 2002-2017 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/can/can-ml.h> 62 #include <linux/ratelimit.h> 63 #include <net/net_namespace.h> 64 #include <net/sock.h> 65 66 #include "af_can.h" 67 68 MODULE_DESCRIPTION("Controller Area Network PF_CAN core"); 69 MODULE_LICENSE("Dual BSD/GPL"); 70 MODULE_AUTHOR("Urs Thuermann <urs.thuermann@volkswagen.de>, " 71 "Oliver Hartkopp <oliver.hartkopp@volkswagen.de>"); 72 73 MODULE_ALIAS_NETPROTO(PF_CAN); 74 75 static int stats_timer __read_mostly = 1; 76 module_param(stats_timer, int, 0444); 77 MODULE_PARM_DESC(stats_timer, "enable timer for statistics (default:on)"); 78 79 static struct kmem_cache *rcv_cache __read_mostly; 80 81 /* table of registered CAN protocols */ 82 static const struct can_proto __rcu *proto_tab[CAN_NPROTO] __read_mostly; 83 static DEFINE_MUTEX(proto_tab_lock); 84 85 static atomic_t skbcounter = ATOMIC_INIT(0); 86 87 /* af_can socket functions */ 88 89 void can_sock_destruct(struct sock *sk) 90 { 91 skb_queue_purge(&sk->sk_receive_queue); 92 skb_queue_purge(&sk->sk_error_queue); 93 } 94 EXPORT_SYMBOL(can_sock_destruct); 95 96 static const struct can_proto *can_get_proto(int protocol) 97 { 98 const struct can_proto *cp; 99 100 rcu_read_lock(); 101 cp = rcu_dereference(proto_tab[protocol]); 102 if (cp && !try_module_get(cp->prot->owner)) 103 cp = NULL; 104 rcu_read_unlock(); 105 106 return cp; 107 } 108 109 static inline void can_put_proto(const struct can_proto *cp) 110 { 111 module_put(cp->prot->owner); 112 } 113 114 static int can_create(struct net *net, struct socket *sock, int protocol, 115 int kern) 116 { 117 struct sock *sk; 118 const struct can_proto *cp; 119 int err = 0; 120 121 sock->state = SS_UNCONNECTED; 122 123 if (protocol < 0 || protocol >= CAN_NPROTO) 124 return -EINVAL; 125 126 cp = can_get_proto(protocol); 127 128 #ifdef CONFIG_MODULES 129 if (!cp) { 130 /* try to load protocol module if kernel is modular */ 131 132 err = request_module("can-proto-%d", protocol); 133 134 /* In case of error we only print a message but don't 135 * return the error code immediately. Below we will 136 * return -EPROTONOSUPPORT 137 */ 138 if (err) 139 pr_err_ratelimited("can: request_module (can-proto-%d) failed.\n", 140 protocol); 141 142 cp = can_get_proto(protocol); 143 } 144 #endif 145 146 /* check for available protocol and correct usage */ 147 148 if (!cp) 149 return -EPROTONOSUPPORT; 150 151 if (cp->type != sock->type) { 152 err = -EPROTOTYPE; 153 goto errout; 154 } 155 156 sock->ops = cp->ops; 157 158 sk = sk_alloc(net, PF_CAN, GFP_KERNEL, cp->prot, kern); 159 if (!sk) { 160 err = -ENOMEM; 161 goto errout; 162 } 163 164 sock_init_data(sock, sk); 165 sk->sk_destruct = can_sock_destruct; 166 167 if (sk->sk_prot->init) 168 err = sk->sk_prot->init(sk); 169 170 if (err) { 171 /* release sk on errors */ 172 sock_orphan(sk); 173 sock_put(sk); 174 } 175 176 errout: 177 can_put_proto(cp); 178 return err; 179 } 180 181 /* af_can tx path */ 182 183 /** 184 * can_send - transmit a CAN frame (optional with local loopback) 185 * @skb: pointer to socket buffer with CAN frame in data section 186 * @loop: loopback for listeners on local CAN sockets (recommended default!) 187 * 188 * Due to the loopback this routine must not be called from hardirq context. 189 * 190 * Return: 191 * 0 on success 192 * -ENETDOWN when the selected interface is down 193 * -ENOBUFS on full driver queue (see net_xmit_errno()) 194 * -ENOMEM when local loopback failed at calling skb_clone() 195 * -EPERM when trying to send on a non-CAN interface 196 * -EMSGSIZE CAN frame size is bigger than CAN interface MTU 197 * -EINVAL when the skb->data does not contain a valid CAN frame 198 */ 199 int can_send(struct sk_buff *skb, int loop) 200 { 201 struct sk_buff *newskb = NULL; 202 struct can_pkg_stats *pkg_stats = dev_net(skb->dev)->can.pkg_stats; 203 int err = -EINVAL; 204 205 if (can_is_canxl_skb(skb)) { 206 skb->protocol = htons(ETH_P_CANXL); 207 } else if (can_is_can_skb(skb)) { 208 skb->protocol = htons(ETH_P_CAN); 209 } else if (can_is_canfd_skb(skb)) { 210 struct canfd_frame *cfd = (struct canfd_frame *)skb->data; 211 212 skb->protocol = htons(ETH_P_CANFD); 213 214 /* set CAN FD flag for CAN FD frames by default */ 215 cfd->flags |= CANFD_FDF; 216 } else { 217 goto inval_skb; 218 } 219 220 /* Make sure the CAN frame can pass the selected CAN netdevice. */ 221 if (unlikely(skb->len > skb->dev->mtu)) { 222 err = -EMSGSIZE; 223 goto inval_skb; 224 } 225 226 if (unlikely(skb->dev->type != ARPHRD_CAN)) { 227 err = -EPERM; 228 goto inval_skb; 229 } 230 231 if (unlikely(!(skb->dev->flags & IFF_UP))) { 232 err = -ENETDOWN; 233 goto inval_skb; 234 } 235 236 skb->ip_summed = CHECKSUM_UNNECESSARY; 237 238 skb_reset_mac_header(skb); 239 skb_reset_network_header(skb); 240 skb_reset_transport_header(skb); 241 242 if (loop) { 243 /* local loopback of sent CAN frames */ 244 245 /* indication for the CAN driver: do loopback */ 246 skb->pkt_type = PACKET_LOOPBACK; 247 248 /* The reference to the originating sock may be required 249 * by the receiving socket to check whether the frame is 250 * its own. Example: can_raw sockopt CAN_RAW_RECV_OWN_MSGS 251 * Therefore we have to ensure that skb->sk remains the 252 * reference to the originating sock by restoring skb->sk 253 * after each skb_clone() or skb_orphan() usage. 254 */ 255 256 if (!(skb->dev->flags & IFF_ECHO)) { 257 /* If the interface is not capable to do loopback 258 * itself, we do it here. 259 */ 260 newskb = skb_clone(skb, GFP_ATOMIC); 261 if (!newskb) { 262 kfree_skb(skb); 263 return -ENOMEM; 264 } 265 266 can_skb_set_owner(newskb, skb->sk); 267 newskb->ip_summed = CHECKSUM_UNNECESSARY; 268 newskb->pkt_type = PACKET_BROADCAST; 269 } 270 } else { 271 /* indication for the CAN driver: no loopback required */ 272 skb->pkt_type = PACKET_HOST; 273 } 274 275 /* send to netdevice */ 276 err = dev_queue_xmit(skb); 277 if (err > 0) 278 err = net_xmit_errno(err); 279 280 if (err) { 281 kfree_skb(newskb); 282 return err; 283 } 284 285 if (newskb) 286 netif_rx(newskb); 287 288 /* update statistics */ 289 pkg_stats->tx_frames++; 290 pkg_stats->tx_frames_delta++; 291 292 return 0; 293 294 inval_skb: 295 kfree_skb(skb); 296 return err; 297 } 298 EXPORT_SYMBOL(can_send); 299 300 /* af_can rx path */ 301 302 static struct can_dev_rcv_lists *can_dev_rcv_lists_find(struct net *net, 303 struct net_device *dev) 304 { 305 if (dev) { 306 struct can_ml_priv *can_ml = can_get_ml_priv(dev); 307 return &can_ml->dev_rcv_lists; 308 } else { 309 return net->can.rx_alldev_list; 310 } 311 } 312 313 /** 314 * effhash - hash function for 29 bit CAN identifier reduction 315 * @can_id: 29 bit CAN identifier 316 * 317 * Description: 318 * To reduce the linear traversal in one linked list of _single_ EFF CAN 319 * frame subscriptions the 29 bit identifier is mapped to 10 bits. 320 * (see CAN_EFF_RCV_HASH_BITS definition) 321 * 322 * Return: 323 * Hash value from 0x000 - 0x3FF ( enforced by CAN_EFF_RCV_HASH_BITS mask ) 324 */ 325 static unsigned int effhash(canid_t can_id) 326 { 327 unsigned int hash; 328 329 hash = can_id; 330 hash ^= can_id >> CAN_EFF_RCV_HASH_BITS; 331 hash ^= can_id >> (2 * CAN_EFF_RCV_HASH_BITS); 332 333 return hash & ((1 << CAN_EFF_RCV_HASH_BITS) - 1); 334 } 335 336 /** 337 * can_rcv_list_find - determine optimal filterlist inside device filter struct 338 * @can_id: pointer to CAN identifier of a given can_filter 339 * @mask: pointer to CAN mask of a given can_filter 340 * @dev_rcv_lists: pointer to the device filter struct 341 * 342 * Description: 343 * Returns the optimal filterlist to reduce the filter handling in the 344 * receive path. This function is called by service functions that need 345 * to register or unregister a can_filter in the filter lists. 346 * 347 * A filter matches in general, when 348 * 349 * <received_can_id> & mask == can_id & mask 350 * 351 * so every bit set in the mask (even CAN_EFF_FLAG, CAN_RTR_FLAG) describe 352 * relevant bits for the filter. 353 * 354 * The filter can be inverted (CAN_INV_FILTER bit set in can_id) or it can 355 * filter for error messages (CAN_ERR_FLAG bit set in mask). For error msg 356 * frames there is a special filterlist and a special rx path filter handling. 357 * 358 * Return: 359 * Pointer to optimal filterlist for the given can_id/mask pair. 360 * Consistency checked mask. 361 * Reduced can_id to have a preprocessed filter compare value. 362 */ 363 static struct hlist_head *can_rcv_list_find(canid_t *can_id, canid_t *mask, 364 struct can_dev_rcv_lists *dev_rcv_lists) 365 { 366 canid_t inv = *can_id & CAN_INV_FILTER; /* save flag before masking */ 367 368 /* filter for error message frames in extra filterlist */ 369 if (*mask & CAN_ERR_FLAG) { 370 /* clear CAN_ERR_FLAG in filter entry */ 371 *mask &= CAN_ERR_MASK; 372 return &dev_rcv_lists->rx[RX_ERR]; 373 } 374 375 /* with cleared CAN_ERR_FLAG we have a simple mask/value filterpair */ 376 377 #define CAN_EFF_RTR_FLAGS (CAN_EFF_FLAG | CAN_RTR_FLAG) 378 379 /* ensure valid values in can_mask for 'SFF only' frame filtering */ 380 if ((*mask & CAN_EFF_FLAG) && !(*can_id & CAN_EFF_FLAG)) 381 *mask &= (CAN_SFF_MASK | CAN_EFF_RTR_FLAGS); 382 383 /* reduce condition testing at receive time */ 384 *can_id &= *mask; 385 386 /* inverse can_id/can_mask filter */ 387 if (inv) 388 return &dev_rcv_lists->rx[RX_INV]; 389 390 /* mask == 0 => no condition testing at receive time */ 391 if (!(*mask)) 392 return &dev_rcv_lists->rx[RX_ALL]; 393 394 /* extra filterlists for the subscription of a single non-RTR can_id */ 395 if (((*mask & CAN_EFF_RTR_FLAGS) == CAN_EFF_RTR_FLAGS) && 396 !(*can_id & CAN_RTR_FLAG)) { 397 if (*can_id & CAN_EFF_FLAG) { 398 if (*mask == (CAN_EFF_MASK | CAN_EFF_RTR_FLAGS)) 399 return &dev_rcv_lists->rx_eff[effhash(*can_id)]; 400 } else { 401 if (*mask == (CAN_SFF_MASK | CAN_EFF_RTR_FLAGS)) 402 return &dev_rcv_lists->rx_sff[*can_id]; 403 } 404 } 405 406 /* default: filter via can_id/can_mask */ 407 return &dev_rcv_lists->rx[RX_FIL]; 408 } 409 410 /** 411 * can_rx_register - subscribe CAN frames from a specific interface 412 * @net: the applicable net namespace 413 * @dev: pointer to netdevice (NULL => subscribe from 'all' CAN devices list) 414 * @can_id: CAN identifier (see description) 415 * @mask: CAN mask (see description) 416 * @func: callback function on filter match 417 * @data: returned parameter for callback function 418 * @ident: string for calling module identification 419 * @sk: socket pointer (might be NULL) 420 * 421 * Description: 422 * Invokes the callback function with the received sk_buff and the given 423 * parameter 'data' on a matching receive filter. A filter matches, when 424 * 425 * <received_can_id> & mask == can_id & mask 426 * 427 * The filter can be inverted (CAN_INV_FILTER bit set in can_id) or it can 428 * filter for error message frames (CAN_ERR_FLAG bit set in mask). 429 * 430 * The provided pointer to the sk_buff is guaranteed to be valid as long as 431 * the callback function is running. The callback function must *not* free 432 * the given sk_buff while processing it's task. When the given sk_buff is 433 * needed after the end of the callback function it must be cloned inside 434 * the callback function with skb_clone(). 435 * 436 * Return: 437 * 0 on success 438 * -ENOMEM on missing cache mem to create subscription entry 439 * -ENODEV unknown device 440 */ 441 int can_rx_register(struct net *net, struct net_device *dev, canid_t can_id, 442 canid_t mask, void (*func)(struct sk_buff *, void *), 443 void *data, char *ident, struct sock *sk) 444 { 445 struct receiver *rcv; 446 struct hlist_head *rcv_list; 447 struct can_dev_rcv_lists *dev_rcv_lists; 448 struct can_rcv_lists_stats *rcv_lists_stats = net->can.rcv_lists_stats; 449 450 /* insert new receiver (dev,canid,mask) -> (func,data) */ 451 452 if (dev && (dev->type != ARPHRD_CAN || !can_get_ml_priv(dev))) 453 return -ENODEV; 454 455 if (dev && !net_eq(net, dev_net(dev))) 456 return -ENODEV; 457 458 rcv = kmem_cache_alloc(rcv_cache, GFP_KERNEL); 459 if (!rcv) 460 return -ENOMEM; 461 462 spin_lock_bh(&net->can.rcvlists_lock); 463 464 dev_rcv_lists = can_dev_rcv_lists_find(net, dev); 465 rcv_list = can_rcv_list_find(&can_id, &mask, dev_rcv_lists); 466 467 rcv->can_id = can_id; 468 rcv->mask = mask; 469 rcv->matches = 0; 470 rcv->func = func; 471 rcv->data = data; 472 rcv->ident = ident; 473 rcv->sk = sk; 474 475 hlist_add_head_rcu(&rcv->list, rcv_list); 476 dev_rcv_lists->entries++; 477 478 rcv_lists_stats->rcv_entries++; 479 rcv_lists_stats->rcv_entries_max = max(rcv_lists_stats->rcv_entries_max, 480 rcv_lists_stats->rcv_entries); 481 spin_unlock_bh(&net->can.rcvlists_lock); 482 483 return 0; 484 } 485 EXPORT_SYMBOL(can_rx_register); 486 487 /* can_rx_delete_receiver - rcu callback for single receiver entry removal */ 488 static void can_rx_delete_receiver(struct rcu_head *rp) 489 { 490 struct receiver *rcv = container_of(rp, struct receiver, rcu); 491 struct sock *sk = rcv->sk; 492 493 kmem_cache_free(rcv_cache, rcv); 494 if (sk) 495 sock_put(sk); 496 } 497 498 /** 499 * can_rx_unregister - unsubscribe CAN frames from a specific interface 500 * @net: the applicable net namespace 501 * @dev: pointer to netdevice (NULL => unsubscribe from 'all' CAN devices list) 502 * @can_id: CAN identifier 503 * @mask: CAN mask 504 * @func: callback function on filter match 505 * @data: returned parameter for callback function 506 * 507 * Description: 508 * Removes subscription entry depending on given (subscription) values. 509 */ 510 void can_rx_unregister(struct net *net, struct net_device *dev, canid_t can_id, 511 canid_t mask, void (*func)(struct sk_buff *, void *), 512 void *data) 513 { 514 struct receiver *rcv = NULL; 515 struct hlist_head *rcv_list; 516 struct can_rcv_lists_stats *rcv_lists_stats = net->can.rcv_lists_stats; 517 struct can_dev_rcv_lists *dev_rcv_lists; 518 519 if (dev && dev->type != ARPHRD_CAN) 520 return; 521 522 if (dev && !net_eq(net, dev_net(dev))) 523 return; 524 525 spin_lock_bh(&net->can.rcvlists_lock); 526 527 dev_rcv_lists = can_dev_rcv_lists_find(net, dev); 528 rcv_list = can_rcv_list_find(&can_id, &mask, dev_rcv_lists); 529 530 /* Search the receiver list for the item to delete. This should 531 * exist, since no receiver may be unregistered that hasn't 532 * been registered before. 533 */ 534 hlist_for_each_entry_rcu(rcv, rcv_list, list) { 535 if (rcv->can_id == can_id && rcv->mask == mask && 536 rcv->func == func && rcv->data == data) 537 break; 538 } 539 540 /* Check for bugs in CAN protocol implementations using af_can.c: 541 * 'rcv' will be NULL if no matching list item was found for removal. 542 * As this case may potentially happen when closing a socket while 543 * the notifier for removing the CAN netdev is running we just print 544 * a warning here. 545 */ 546 if (!rcv) { 547 pr_warn("can: receive list entry not found for dev %s, id %03X, mask %03X\n", 548 DNAME(dev), can_id, mask); 549 goto out; 550 } 551 552 hlist_del_rcu(&rcv->list); 553 dev_rcv_lists->entries--; 554 555 if (rcv_lists_stats->rcv_entries > 0) 556 rcv_lists_stats->rcv_entries--; 557 558 out: 559 spin_unlock_bh(&net->can.rcvlists_lock); 560 561 /* schedule the receiver item for deletion */ 562 if (rcv) { 563 if (rcv->sk) 564 sock_hold(rcv->sk); 565 call_rcu(&rcv->rcu, can_rx_delete_receiver); 566 } 567 } 568 EXPORT_SYMBOL(can_rx_unregister); 569 570 static inline void deliver(struct sk_buff *skb, struct receiver *rcv) 571 { 572 rcv->func(skb, rcv->data); 573 rcv->matches++; 574 } 575 576 static int can_rcv_filter(struct can_dev_rcv_lists *dev_rcv_lists, struct sk_buff *skb) 577 { 578 struct receiver *rcv; 579 int matches = 0; 580 struct can_frame *cf = (struct can_frame *)skb->data; 581 canid_t can_id = cf->can_id; 582 583 if (dev_rcv_lists->entries == 0) 584 return 0; 585 586 if (can_id & CAN_ERR_FLAG) { 587 /* check for error message frame entries only */ 588 hlist_for_each_entry_rcu(rcv, &dev_rcv_lists->rx[RX_ERR], list) { 589 if (can_id & rcv->mask) { 590 deliver(skb, rcv); 591 matches++; 592 } 593 } 594 return matches; 595 } 596 597 /* check for unfiltered entries */ 598 hlist_for_each_entry_rcu(rcv, &dev_rcv_lists->rx[RX_ALL], list) { 599 deliver(skb, rcv); 600 matches++; 601 } 602 603 /* check for can_id/mask entries */ 604 hlist_for_each_entry_rcu(rcv, &dev_rcv_lists->rx[RX_FIL], list) { 605 if ((can_id & rcv->mask) == rcv->can_id) { 606 deliver(skb, rcv); 607 matches++; 608 } 609 } 610 611 /* check for inverted can_id/mask entries */ 612 hlist_for_each_entry_rcu(rcv, &dev_rcv_lists->rx[RX_INV], list) { 613 if ((can_id & rcv->mask) != rcv->can_id) { 614 deliver(skb, rcv); 615 matches++; 616 } 617 } 618 619 /* check filterlists for single non-RTR can_ids */ 620 if (can_id & CAN_RTR_FLAG) 621 return matches; 622 623 if (can_id & CAN_EFF_FLAG) { 624 hlist_for_each_entry_rcu(rcv, &dev_rcv_lists->rx_eff[effhash(can_id)], list) { 625 if (rcv->can_id == can_id) { 626 deliver(skb, rcv); 627 matches++; 628 } 629 } 630 } else { 631 can_id &= CAN_SFF_MASK; 632 hlist_for_each_entry_rcu(rcv, &dev_rcv_lists->rx_sff[can_id], list) { 633 deliver(skb, rcv); 634 matches++; 635 } 636 } 637 638 return matches; 639 } 640 641 static void can_receive(struct sk_buff *skb, struct net_device *dev) 642 { 643 struct can_dev_rcv_lists *dev_rcv_lists; 644 struct net *net = dev_net(dev); 645 struct can_pkg_stats *pkg_stats = net->can.pkg_stats; 646 int matches; 647 648 /* update statistics */ 649 pkg_stats->rx_frames++; 650 pkg_stats->rx_frames_delta++; 651 652 /* create non-zero unique skb identifier together with *skb */ 653 while (!(can_skb_prv(skb)->skbcnt)) 654 can_skb_prv(skb)->skbcnt = atomic_inc_return(&skbcounter); 655 656 rcu_read_lock(); 657 658 /* deliver the packet to sockets listening on all devices */ 659 matches = can_rcv_filter(net->can.rx_alldev_list, skb); 660 661 /* find receive list for this device */ 662 dev_rcv_lists = can_dev_rcv_lists_find(net, dev); 663 matches += can_rcv_filter(dev_rcv_lists, skb); 664 665 rcu_read_unlock(); 666 667 /* consume the skbuff allocated by the netdevice driver */ 668 consume_skb(skb); 669 670 if (matches > 0) { 671 pkg_stats->matches++; 672 pkg_stats->matches_delta++; 673 } 674 } 675 676 static int can_rcv(struct sk_buff *skb, struct net_device *dev, 677 struct packet_type *pt, struct net_device *orig_dev) 678 { 679 if (unlikely(dev->type != ARPHRD_CAN || !can_get_ml_priv(dev) || !can_is_can_skb(skb))) { 680 pr_warn_once("PF_CAN: dropped non conform CAN skbuff: dev type %d, len %d\n", 681 dev->type, skb->len); 682 683 kfree_skb(skb); 684 return NET_RX_DROP; 685 } 686 687 can_receive(skb, dev); 688 return NET_RX_SUCCESS; 689 } 690 691 static int canfd_rcv(struct sk_buff *skb, struct net_device *dev, 692 struct packet_type *pt, struct net_device *orig_dev) 693 { 694 if (unlikely(dev->type != ARPHRD_CAN || !can_get_ml_priv(dev) || !can_is_canfd_skb(skb))) { 695 pr_warn_once("PF_CAN: dropped non conform CAN FD skbuff: dev type %d, len %d\n", 696 dev->type, skb->len); 697 698 kfree_skb(skb); 699 return NET_RX_DROP; 700 } 701 702 can_receive(skb, dev); 703 return NET_RX_SUCCESS; 704 } 705 706 static int canxl_rcv(struct sk_buff *skb, struct net_device *dev, 707 struct packet_type *pt, struct net_device *orig_dev) 708 { 709 if (unlikely(dev->type != ARPHRD_CAN || !can_get_ml_priv(dev) || !can_is_canxl_skb(skb))) { 710 pr_warn_once("PF_CAN: dropped non conform CAN XL skbuff: dev type %d, len %d\n", 711 dev->type, skb->len); 712 713 kfree_skb(skb); 714 return NET_RX_DROP; 715 } 716 717 can_receive(skb, dev); 718 return NET_RX_SUCCESS; 719 } 720 721 /* af_can protocol functions */ 722 723 /** 724 * can_proto_register - register CAN transport protocol 725 * @cp: pointer to CAN protocol structure 726 * 727 * Return: 728 * 0 on success 729 * -EINVAL invalid (out of range) protocol number 730 * -EBUSY protocol already in use 731 * -ENOBUF if proto_register() fails 732 */ 733 int can_proto_register(const struct can_proto *cp) 734 { 735 int proto = cp->protocol; 736 int err = 0; 737 738 if (proto < 0 || proto >= CAN_NPROTO) { 739 pr_err("can: protocol number %d out of range\n", proto); 740 return -EINVAL; 741 } 742 743 err = proto_register(cp->prot, 0); 744 if (err < 0) 745 return err; 746 747 mutex_lock(&proto_tab_lock); 748 749 if (rcu_access_pointer(proto_tab[proto])) { 750 pr_err("can: protocol %d already registered\n", proto); 751 err = -EBUSY; 752 } else { 753 RCU_INIT_POINTER(proto_tab[proto], cp); 754 } 755 756 mutex_unlock(&proto_tab_lock); 757 758 if (err < 0) 759 proto_unregister(cp->prot); 760 761 return err; 762 } 763 EXPORT_SYMBOL(can_proto_register); 764 765 /** 766 * can_proto_unregister - unregister CAN transport protocol 767 * @cp: pointer to CAN protocol structure 768 */ 769 void can_proto_unregister(const struct can_proto *cp) 770 { 771 int proto = cp->protocol; 772 773 mutex_lock(&proto_tab_lock); 774 BUG_ON(rcu_access_pointer(proto_tab[proto]) != cp); 775 RCU_INIT_POINTER(proto_tab[proto], NULL); 776 mutex_unlock(&proto_tab_lock); 777 778 synchronize_rcu(); 779 780 proto_unregister(cp->prot); 781 } 782 EXPORT_SYMBOL(can_proto_unregister); 783 784 static int can_pernet_init(struct net *net) 785 { 786 spin_lock_init(&net->can.rcvlists_lock); 787 net->can.rx_alldev_list = 788 kzalloc(sizeof(*net->can.rx_alldev_list), GFP_KERNEL); 789 if (!net->can.rx_alldev_list) 790 goto out; 791 net->can.pkg_stats = kzalloc(sizeof(*net->can.pkg_stats), GFP_KERNEL); 792 if (!net->can.pkg_stats) 793 goto out_free_rx_alldev_list; 794 net->can.rcv_lists_stats = kzalloc(sizeof(*net->can.rcv_lists_stats), GFP_KERNEL); 795 if (!net->can.rcv_lists_stats) 796 goto out_free_pkg_stats; 797 798 if (IS_ENABLED(CONFIG_PROC_FS)) { 799 /* the statistics are updated every second (timer triggered) */ 800 if (stats_timer) { 801 timer_setup(&net->can.stattimer, can_stat_update, 802 0); 803 mod_timer(&net->can.stattimer, 804 round_jiffies(jiffies + HZ)); 805 } 806 net->can.pkg_stats->jiffies_init = jiffies; 807 can_init_proc(net); 808 } 809 810 return 0; 811 812 out_free_pkg_stats: 813 kfree(net->can.pkg_stats); 814 out_free_rx_alldev_list: 815 kfree(net->can.rx_alldev_list); 816 out: 817 return -ENOMEM; 818 } 819 820 static void can_pernet_exit(struct net *net) 821 { 822 if (IS_ENABLED(CONFIG_PROC_FS)) { 823 can_remove_proc(net); 824 if (stats_timer) 825 del_timer_sync(&net->can.stattimer); 826 } 827 828 kfree(net->can.rx_alldev_list); 829 kfree(net->can.pkg_stats); 830 kfree(net->can.rcv_lists_stats); 831 } 832 833 /* af_can module init/exit functions */ 834 835 static struct packet_type can_packet __read_mostly = { 836 .type = cpu_to_be16(ETH_P_CAN), 837 .func = can_rcv, 838 }; 839 840 static struct packet_type canfd_packet __read_mostly = { 841 .type = cpu_to_be16(ETH_P_CANFD), 842 .func = canfd_rcv, 843 }; 844 845 static struct packet_type canxl_packet __read_mostly = { 846 .type = cpu_to_be16(ETH_P_CANXL), 847 .func = canxl_rcv, 848 }; 849 850 static const struct net_proto_family can_family_ops = { 851 .family = PF_CAN, 852 .create = can_create, 853 .owner = THIS_MODULE, 854 }; 855 856 static struct pernet_operations can_pernet_ops __read_mostly = { 857 .init = can_pernet_init, 858 .exit = can_pernet_exit, 859 }; 860 861 static __init int can_init(void) 862 { 863 int err; 864 865 /* check for correct padding to be able to use the structs similarly */ 866 BUILD_BUG_ON(offsetof(struct can_frame, len) != 867 offsetof(struct canfd_frame, len) || 868 offsetof(struct can_frame, len) != 869 offsetof(struct canxl_frame, flags) || 870 offsetof(struct can_frame, data) != 871 offsetof(struct canfd_frame, data)); 872 873 pr_info("can: controller area network core\n"); 874 875 rcv_cache = kmem_cache_create("can_receiver", sizeof(struct receiver), 876 0, 0, NULL); 877 if (!rcv_cache) 878 return -ENOMEM; 879 880 err = register_pernet_subsys(&can_pernet_ops); 881 if (err) 882 goto out_pernet; 883 884 /* protocol register */ 885 err = sock_register(&can_family_ops); 886 if (err) 887 goto out_sock; 888 889 dev_add_pack(&can_packet); 890 dev_add_pack(&canfd_packet); 891 dev_add_pack(&canxl_packet); 892 893 return 0; 894 895 out_sock: 896 unregister_pernet_subsys(&can_pernet_ops); 897 out_pernet: 898 kmem_cache_destroy(rcv_cache); 899 900 return err; 901 } 902 903 static __exit void can_exit(void) 904 { 905 /* protocol unregister */ 906 dev_remove_pack(&canxl_packet); 907 dev_remove_pack(&canfd_packet); 908 dev_remove_pack(&can_packet); 909 sock_unregister(PF_CAN); 910 911 unregister_pernet_subsys(&can_pernet_ops); 912 913 rcu_barrier(); /* Wait for completion of call_rcu()'s */ 914 915 kmem_cache_destroy(rcv_cache); 916 } 917 918 module_init(can_init); 919 module_exit(can_exit); 920