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 int err = 0; 450 451 /* insert new receiver (dev,canid,mask) -> (func,data) */ 452 453 if (dev && dev->type != ARPHRD_CAN) 454 return -ENODEV; 455 456 if (dev && !net_eq(net, dev_net(dev))) 457 return -ENODEV; 458 459 rcv = kmem_cache_alloc(rcv_cache, GFP_KERNEL); 460 if (!rcv) 461 return -ENOMEM; 462 463 spin_lock_bh(&net->can.rcvlists_lock); 464 465 dev_rcv_lists = can_dev_rcv_lists_find(net, dev); 466 rcv_list = can_rcv_list_find(&can_id, &mask, dev_rcv_lists); 467 468 rcv->can_id = can_id; 469 rcv->mask = mask; 470 rcv->matches = 0; 471 rcv->func = func; 472 rcv->data = data; 473 rcv->ident = ident; 474 rcv->sk = sk; 475 476 hlist_add_head_rcu(&rcv->list, rcv_list); 477 dev_rcv_lists->entries++; 478 479 rcv_lists_stats->rcv_entries++; 480 rcv_lists_stats->rcv_entries_max = max(rcv_lists_stats->rcv_entries_max, 481 rcv_lists_stats->rcv_entries); 482 spin_unlock_bh(&net->can.rcvlists_lock); 483 484 return err; 485 } 486 EXPORT_SYMBOL(can_rx_register); 487 488 /* can_rx_delete_receiver - rcu callback for single receiver entry removal */ 489 static void can_rx_delete_receiver(struct rcu_head *rp) 490 { 491 struct receiver *rcv = container_of(rp, struct receiver, rcu); 492 struct sock *sk = rcv->sk; 493 494 kmem_cache_free(rcv_cache, rcv); 495 if (sk) 496 sock_put(sk); 497 } 498 499 /** 500 * can_rx_unregister - unsubscribe CAN frames from a specific interface 501 * @net: the applicable net namespace 502 * @dev: pointer to netdevice (NULL => unsubscribe from 'all' CAN devices list) 503 * @can_id: CAN identifier 504 * @mask: CAN mask 505 * @func: callback function on filter match 506 * @data: returned parameter for callback function 507 * 508 * Description: 509 * Removes subscription entry depending on given (subscription) values. 510 */ 511 void can_rx_unregister(struct net *net, struct net_device *dev, canid_t can_id, 512 canid_t mask, void (*func)(struct sk_buff *, void *), 513 void *data) 514 { 515 struct receiver *rcv = NULL; 516 struct hlist_head *rcv_list; 517 struct can_rcv_lists_stats *rcv_lists_stats = net->can.rcv_lists_stats; 518 struct can_dev_rcv_lists *dev_rcv_lists; 519 520 if (dev && dev->type != ARPHRD_CAN) 521 return; 522 523 if (dev && !net_eq(net, dev_net(dev))) 524 return; 525 526 spin_lock_bh(&net->can.rcvlists_lock); 527 528 dev_rcv_lists = can_dev_rcv_lists_find(net, dev); 529 rcv_list = can_rcv_list_find(&can_id, &mask, dev_rcv_lists); 530 531 /* Search the receiver list for the item to delete. This should 532 * exist, since no receiver may be unregistered that hasn't 533 * been registered before. 534 */ 535 hlist_for_each_entry_rcu(rcv, rcv_list, list) { 536 if (rcv->can_id == can_id && rcv->mask == mask && 537 rcv->func == func && rcv->data == data) 538 break; 539 } 540 541 /* Check for bugs in CAN protocol implementations using af_can.c: 542 * 'rcv' will be NULL if no matching list item was found for removal. 543 * As this case may potentially happen when closing a socket while 544 * the notifier for removing the CAN netdev is running we just print 545 * a warning here. 546 */ 547 if (!rcv) { 548 pr_warn("can: receive list entry not found for dev %s, id %03X, mask %03X\n", 549 DNAME(dev), can_id, mask); 550 goto out; 551 } 552 553 hlist_del_rcu(&rcv->list); 554 dev_rcv_lists->entries--; 555 556 if (rcv_lists_stats->rcv_entries > 0) 557 rcv_lists_stats->rcv_entries--; 558 559 out: 560 spin_unlock_bh(&net->can.rcvlists_lock); 561 562 /* schedule the receiver item for deletion */ 563 if (rcv) { 564 if (rcv->sk) 565 sock_hold(rcv->sk); 566 call_rcu(&rcv->rcu, can_rx_delete_receiver); 567 } 568 } 569 EXPORT_SYMBOL(can_rx_unregister); 570 571 static inline void deliver(struct sk_buff *skb, struct receiver *rcv) 572 { 573 rcv->func(skb, rcv->data); 574 rcv->matches++; 575 } 576 577 static int can_rcv_filter(struct can_dev_rcv_lists *dev_rcv_lists, struct sk_buff *skb) 578 { 579 struct receiver *rcv; 580 int matches = 0; 581 struct can_frame *cf = (struct can_frame *)skb->data; 582 canid_t can_id = cf->can_id; 583 584 if (dev_rcv_lists->entries == 0) 585 return 0; 586 587 if (can_id & CAN_ERR_FLAG) { 588 /* check for error message frame entries only */ 589 hlist_for_each_entry_rcu(rcv, &dev_rcv_lists->rx[RX_ERR], list) { 590 if (can_id & rcv->mask) { 591 deliver(skb, rcv); 592 matches++; 593 } 594 } 595 return matches; 596 } 597 598 /* check for unfiltered entries */ 599 hlist_for_each_entry_rcu(rcv, &dev_rcv_lists->rx[RX_ALL], list) { 600 deliver(skb, rcv); 601 matches++; 602 } 603 604 /* check for can_id/mask entries */ 605 hlist_for_each_entry_rcu(rcv, &dev_rcv_lists->rx[RX_FIL], list) { 606 if ((can_id & rcv->mask) == rcv->can_id) { 607 deliver(skb, rcv); 608 matches++; 609 } 610 } 611 612 /* check for inverted can_id/mask entries */ 613 hlist_for_each_entry_rcu(rcv, &dev_rcv_lists->rx[RX_INV], list) { 614 if ((can_id & rcv->mask) != rcv->can_id) { 615 deliver(skb, rcv); 616 matches++; 617 } 618 } 619 620 /* check filterlists for single non-RTR can_ids */ 621 if (can_id & CAN_RTR_FLAG) 622 return matches; 623 624 if (can_id & CAN_EFF_FLAG) { 625 hlist_for_each_entry_rcu(rcv, &dev_rcv_lists->rx_eff[effhash(can_id)], list) { 626 if (rcv->can_id == can_id) { 627 deliver(skb, rcv); 628 matches++; 629 } 630 } 631 } else { 632 can_id &= CAN_SFF_MASK; 633 hlist_for_each_entry_rcu(rcv, &dev_rcv_lists->rx_sff[can_id], list) { 634 deliver(skb, rcv); 635 matches++; 636 } 637 } 638 639 return matches; 640 } 641 642 static void can_receive(struct sk_buff *skb, struct net_device *dev) 643 { 644 struct can_dev_rcv_lists *dev_rcv_lists; 645 struct net *net = dev_net(dev); 646 struct can_pkg_stats *pkg_stats = net->can.pkg_stats; 647 int matches; 648 649 /* update statistics */ 650 pkg_stats->rx_frames++; 651 pkg_stats->rx_frames_delta++; 652 653 /* create non-zero unique skb identifier together with *skb */ 654 while (!(can_skb_prv(skb)->skbcnt)) 655 can_skb_prv(skb)->skbcnt = atomic_inc_return(&skbcounter); 656 657 rcu_read_lock(); 658 659 /* deliver the packet to sockets listening on all devices */ 660 matches = can_rcv_filter(net->can.rx_alldev_list, skb); 661 662 /* find receive list for this device */ 663 dev_rcv_lists = can_dev_rcv_lists_find(net, dev); 664 matches += can_rcv_filter(dev_rcv_lists, skb); 665 666 rcu_read_unlock(); 667 668 /* consume the skbuff allocated by the netdevice driver */ 669 consume_skb(skb); 670 671 if (matches > 0) { 672 pkg_stats->matches++; 673 pkg_stats->matches_delta++; 674 } 675 } 676 677 static int can_rcv(struct sk_buff *skb, struct net_device *dev, 678 struct packet_type *pt, struct net_device *orig_dev) 679 { 680 if (unlikely(dev->type != ARPHRD_CAN || (!can_is_can_skb(skb)))) { 681 pr_warn_once("PF_CAN: dropped non conform CAN skbuff: dev type %d, len %d\n", 682 dev->type, skb->len); 683 684 kfree_skb(skb); 685 return NET_RX_DROP; 686 } 687 688 can_receive(skb, dev); 689 return NET_RX_SUCCESS; 690 } 691 692 static int canfd_rcv(struct sk_buff *skb, struct net_device *dev, 693 struct packet_type *pt, struct net_device *orig_dev) 694 { 695 if (unlikely(dev->type != ARPHRD_CAN || (!can_is_canfd_skb(skb)))) { 696 pr_warn_once("PF_CAN: dropped non conform CAN FD skbuff: dev type %d, len %d\n", 697 dev->type, skb->len); 698 699 kfree_skb(skb); 700 return NET_RX_DROP; 701 } 702 703 can_receive(skb, dev); 704 return NET_RX_SUCCESS; 705 } 706 707 static int canxl_rcv(struct sk_buff *skb, struct net_device *dev, 708 struct packet_type *pt, struct net_device *orig_dev) 709 { 710 if (unlikely(dev->type != ARPHRD_CAN || (!can_is_canxl_skb(skb)))) { 711 pr_warn_once("PF_CAN: dropped non conform CAN XL skbuff: dev type %d, len %d\n", 712 dev->type, skb->len); 713 714 kfree_skb(skb); 715 return NET_RX_DROP; 716 } 717 718 can_receive(skb, dev); 719 return NET_RX_SUCCESS; 720 } 721 722 /* af_can protocol functions */ 723 724 /** 725 * can_proto_register - register CAN transport protocol 726 * @cp: pointer to CAN protocol structure 727 * 728 * Return: 729 * 0 on success 730 * -EINVAL invalid (out of range) protocol number 731 * -EBUSY protocol already in use 732 * -ENOBUF if proto_register() fails 733 */ 734 int can_proto_register(const struct can_proto *cp) 735 { 736 int proto = cp->protocol; 737 int err = 0; 738 739 if (proto < 0 || proto >= CAN_NPROTO) { 740 pr_err("can: protocol number %d out of range\n", proto); 741 return -EINVAL; 742 } 743 744 err = proto_register(cp->prot, 0); 745 if (err < 0) 746 return err; 747 748 mutex_lock(&proto_tab_lock); 749 750 if (rcu_access_pointer(proto_tab[proto])) { 751 pr_err("can: protocol %d already registered\n", proto); 752 err = -EBUSY; 753 } else { 754 RCU_INIT_POINTER(proto_tab[proto], cp); 755 } 756 757 mutex_unlock(&proto_tab_lock); 758 759 if (err < 0) 760 proto_unregister(cp->prot); 761 762 return err; 763 } 764 EXPORT_SYMBOL(can_proto_register); 765 766 /** 767 * can_proto_unregister - unregister CAN transport protocol 768 * @cp: pointer to CAN protocol structure 769 */ 770 void can_proto_unregister(const struct can_proto *cp) 771 { 772 int proto = cp->protocol; 773 774 mutex_lock(&proto_tab_lock); 775 BUG_ON(rcu_access_pointer(proto_tab[proto]) != cp); 776 RCU_INIT_POINTER(proto_tab[proto], NULL); 777 mutex_unlock(&proto_tab_lock); 778 779 synchronize_rcu(); 780 781 proto_unregister(cp->prot); 782 } 783 EXPORT_SYMBOL(can_proto_unregister); 784 785 static int can_pernet_init(struct net *net) 786 { 787 spin_lock_init(&net->can.rcvlists_lock); 788 net->can.rx_alldev_list = 789 kzalloc(sizeof(*net->can.rx_alldev_list), GFP_KERNEL); 790 if (!net->can.rx_alldev_list) 791 goto out; 792 net->can.pkg_stats = kzalloc(sizeof(*net->can.pkg_stats), GFP_KERNEL); 793 if (!net->can.pkg_stats) 794 goto out_free_rx_alldev_list; 795 net->can.rcv_lists_stats = kzalloc(sizeof(*net->can.rcv_lists_stats), GFP_KERNEL); 796 if (!net->can.rcv_lists_stats) 797 goto out_free_pkg_stats; 798 799 if (IS_ENABLED(CONFIG_PROC_FS)) { 800 /* the statistics are updated every second (timer triggered) */ 801 if (stats_timer) { 802 timer_setup(&net->can.stattimer, can_stat_update, 803 0); 804 mod_timer(&net->can.stattimer, 805 round_jiffies(jiffies + HZ)); 806 } 807 net->can.pkg_stats->jiffies_init = jiffies; 808 can_init_proc(net); 809 } 810 811 return 0; 812 813 out_free_pkg_stats: 814 kfree(net->can.pkg_stats); 815 out_free_rx_alldev_list: 816 kfree(net->can.rx_alldev_list); 817 out: 818 return -ENOMEM; 819 } 820 821 static void can_pernet_exit(struct net *net) 822 { 823 if (IS_ENABLED(CONFIG_PROC_FS)) { 824 can_remove_proc(net); 825 if (stats_timer) 826 del_timer_sync(&net->can.stattimer); 827 } 828 829 kfree(net->can.rx_alldev_list); 830 kfree(net->can.pkg_stats); 831 kfree(net->can.rcv_lists_stats); 832 } 833 834 /* af_can module init/exit functions */ 835 836 static struct packet_type can_packet __read_mostly = { 837 .type = cpu_to_be16(ETH_P_CAN), 838 .func = can_rcv, 839 }; 840 841 static struct packet_type canfd_packet __read_mostly = { 842 .type = cpu_to_be16(ETH_P_CANFD), 843 .func = canfd_rcv, 844 }; 845 846 static struct packet_type canxl_packet __read_mostly = { 847 .type = cpu_to_be16(ETH_P_CANXL), 848 .func = canxl_rcv, 849 }; 850 851 static const struct net_proto_family can_family_ops = { 852 .family = PF_CAN, 853 .create = can_create, 854 .owner = THIS_MODULE, 855 }; 856 857 static struct pernet_operations can_pernet_ops __read_mostly = { 858 .init = can_pernet_init, 859 .exit = can_pernet_exit, 860 }; 861 862 static __init int can_init(void) 863 { 864 int err; 865 866 /* check for correct padding to be able to use the structs similarly */ 867 BUILD_BUG_ON(offsetof(struct can_frame, len) != 868 offsetof(struct canfd_frame, len) || 869 offsetof(struct can_frame, data) != 870 offsetof(struct canfd_frame, data)); 871 872 pr_info("can: controller area network core\n"); 873 874 rcv_cache = kmem_cache_create("can_receiver", sizeof(struct receiver), 875 0, 0, NULL); 876 if (!rcv_cache) 877 return -ENOMEM; 878 879 err = register_pernet_subsys(&can_pernet_ops); 880 if (err) 881 goto out_pernet; 882 883 /* protocol register */ 884 err = sock_register(&can_family_ops); 885 if (err) 886 goto out_sock; 887 888 dev_add_pack(&can_packet); 889 dev_add_pack(&canfd_packet); 890 dev_add_pack(&canxl_packet); 891 892 return 0; 893 894 out_sock: 895 unregister_pernet_subsys(&can_pernet_ops); 896 out_pernet: 897 kmem_cache_destroy(rcv_cache); 898 899 return err; 900 } 901 902 static __exit void can_exit(void) 903 { 904 /* protocol unregister */ 905 dev_remove_pack(&canfd_packet); 906 dev_remove_pack(&can_packet); 907 sock_unregister(PF_CAN); 908 909 unregister_pernet_subsys(&can_pernet_ops); 910 911 rcu_barrier(); /* Wait for completion of call_rcu()'s */ 912 913 kmem_cache_destroy(rcv_cache); 914 } 915 916 module_init(can_init); 917 module_exit(can_exit); 918