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 canfd_frame *cfd = (struct canfd_frame *)skb->data; 203 struct can_pkg_stats *pkg_stats = dev_net(skb->dev)->can.pkg_stats; 204 int err = -EINVAL; 205 206 if (skb->len == CAN_MTU) { 207 skb->protocol = htons(ETH_P_CAN); 208 if (unlikely(cfd->len > CAN_MAX_DLEN)) 209 goto inval_skb; 210 } else if (skb->len == CANFD_MTU) { 211 skb->protocol = htons(ETH_P_CANFD); 212 if (unlikely(cfd->len > CANFD_MAX_DLEN)) 213 goto inval_skb; 214 } else { 215 goto inval_skb; 216 } 217 218 /* Make sure the CAN frame can pass the selected CAN netdevice. 219 * As structs can_frame and canfd_frame are similar, we can provide 220 * CAN FD frames to legacy CAN drivers as long as the length is <= 8 221 */ 222 if (unlikely(skb->len > skb->dev->mtu && cfd->len > CAN_MAX_DLEN)) { 223 err = -EMSGSIZE; 224 goto inval_skb; 225 } 226 227 if (unlikely(skb->dev->type != ARPHRD_CAN)) { 228 err = -EPERM; 229 goto inval_skb; 230 } 231 232 if (unlikely(!(skb->dev->flags & IFF_UP))) { 233 err = -ENETDOWN; 234 goto inval_skb; 235 } 236 237 skb->ip_summed = CHECKSUM_UNNECESSARY; 238 239 skb_reset_mac_header(skb); 240 skb_reset_network_header(skb); 241 skb_reset_transport_header(skb); 242 243 if (loop) { 244 /* local loopback of sent CAN frames */ 245 246 /* indication for the CAN driver: do loopback */ 247 skb->pkt_type = PACKET_LOOPBACK; 248 249 /* The reference to the originating sock may be required 250 * by the receiving socket to check whether the frame is 251 * its own. Example: can_raw sockopt CAN_RAW_RECV_OWN_MSGS 252 * Therefore we have to ensure that skb->sk remains the 253 * reference to the originating sock by restoring skb->sk 254 * after each skb_clone() or skb_orphan() usage. 255 */ 256 257 if (!(skb->dev->flags & IFF_ECHO)) { 258 /* If the interface is not capable to do loopback 259 * itself, we do it here. 260 */ 261 newskb = skb_clone(skb, GFP_ATOMIC); 262 if (!newskb) { 263 kfree_skb(skb); 264 return -ENOMEM; 265 } 266 267 can_skb_set_owner(newskb, skb->sk); 268 newskb->ip_summed = CHECKSUM_UNNECESSARY; 269 newskb->pkt_type = PACKET_BROADCAST; 270 } 271 } else { 272 /* indication for the CAN driver: no loopback required */ 273 skb->pkt_type = PACKET_HOST; 274 } 275 276 /* send to netdevice */ 277 err = dev_queue_xmit(skb); 278 if (err > 0) 279 err = net_xmit_errno(err); 280 281 if (err) { 282 kfree_skb(newskb); 283 return err; 284 } 285 286 if (newskb) 287 netif_rx_ni(newskb); 288 289 /* update statistics */ 290 pkg_stats->tx_frames++; 291 pkg_stats->tx_frames_delta++; 292 293 return 0; 294 295 inval_skb: 296 kfree_skb(skb); 297 return err; 298 } 299 EXPORT_SYMBOL(can_send); 300 301 /* af_can rx path */ 302 303 static struct can_dev_rcv_lists *can_dev_rcv_lists_find(struct net *net, 304 struct net_device *dev) 305 { 306 if (dev) { 307 struct can_ml_priv *can_ml = can_get_ml_priv(dev); 308 return &can_ml->dev_rcv_lists; 309 } else { 310 return net->can.rx_alldev_list; 311 } 312 } 313 314 /** 315 * effhash - hash function for 29 bit CAN identifier reduction 316 * @can_id: 29 bit CAN identifier 317 * 318 * Description: 319 * To reduce the linear traversal in one linked list of _single_ EFF CAN 320 * frame subscriptions the 29 bit identifier is mapped to 10 bits. 321 * (see CAN_EFF_RCV_HASH_BITS definition) 322 * 323 * Return: 324 * Hash value from 0x000 - 0x3FF ( enforced by CAN_EFF_RCV_HASH_BITS mask ) 325 */ 326 static unsigned int effhash(canid_t can_id) 327 { 328 unsigned int hash; 329 330 hash = can_id; 331 hash ^= can_id >> CAN_EFF_RCV_HASH_BITS; 332 hash ^= can_id >> (2 * CAN_EFF_RCV_HASH_BITS); 333 334 return hash & ((1 << CAN_EFF_RCV_HASH_BITS) - 1); 335 } 336 337 /** 338 * can_rcv_list_find - determine optimal filterlist inside device filter struct 339 * @can_id: pointer to CAN identifier of a given can_filter 340 * @mask: pointer to CAN mask of a given can_filter 341 * @dev_rcv_lists: pointer to the device filter struct 342 * 343 * Description: 344 * Returns the optimal filterlist to reduce the filter handling in the 345 * receive path. This function is called by service functions that need 346 * to register or unregister a can_filter in the filter lists. 347 * 348 * A filter matches in general, when 349 * 350 * <received_can_id> & mask == can_id & mask 351 * 352 * so every bit set in the mask (even CAN_EFF_FLAG, CAN_RTR_FLAG) describe 353 * relevant bits for the filter. 354 * 355 * The filter can be inverted (CAN_INV_FILTER bit set in can_id) or it can 356 * filter for error messages (CAN_ERR_FLAG bit set in mask). For error msg 357 * frames there is a special filterlist and a special rx path filter handling. 358 * 359 * Return: 360 * Pointer to optimal filterlist for the given can_id/mask pair. 361 * Consistency checked mask. 362 * Reduced can_id to have a preprocessed filter compare value. 363 */ 364 static struct hlist_head *can_rcv_list_find(canid_t *can_id, canid_t *mask, 365 struct can_dev_rcv_lists *dev_rcv_lists) 366 { 367 canid_t inv = *can_id & CAN_INV_FILTER; /* save flag before masking */ 368 369 /* filter for error message frames in extra filterlist */ 370 if (*mask & CAN_ERR_FLAG) { 371 /* clear CAN_ERR_FLAG in filter entry */ 372 *mask &= CAN_ERR_MASK; 373 return &dev_rcv_lists->rx[RX_ERR]; 374 } 375 376 /* with cleared CAN_ERR_FLAG we have a simple mask/value filterpair */ 377 378 #define CAN_EFF_RTR_FLAGS (CAN_EFF_FLAG | CAN_RTR_FLAG) 379 380 /* ensure valid values in can_mask for 'SFF only' frame filtering */ 381 if ((*mask & CAN_EFF_FLAG) && !(*can_id & CAN_EFF_FLAG)) 382 *mask &= (CAN_SFF_MASK | CAN_EFF_RTR_FLAGS); 383 384 /* reduce condition testing at receive time */ 385 *can_id &= *mask; 386 387 /* inverse can_id/can_mask filter */ 388 if (inv) 389 return &dev_rcv_lists->rx[RX_INV]; 390 391 /* mask == 0 => no condition testing at receive time */ 392 if (!(*mask)) 393 return &dev_rcv_lists->rx[RX_ALL]; 394 395 /* extra filterlists for the subscription of a single non-RTR can_id */ 396 if (((*mask & CAN_EFF_RTR_FLAGS) == CAN_EFF_RTR_FLAGS) && 397 !(*can_id & CAN_RTR_FLAG)) { 398 if (*can_id & CAN_EFF_FLAG) { 399 if (*mask == (CAN_EFF_MASK | CAN_EFF_RTR_FLAGS)) 400 return &dev_rcv_lists->rx_eff[effhash(*can_id)]; 401 } else { 402 if (*mask == (CAN_SFF_MASK | CAN_EFF_RTR_FLAGS)) 403 return &dev_rcv_lists->rx_sff[*can_id]; 404 } 405 } 406 407 /* default: filter via can_id/can_mask */ 408 return &dev_rcv_lists->rx[RX_FIL]; 409 } 410 411 /** 412 * can_rx_register - subscribe CAN frames from a specific interface 413 * @net: the applicable net namespace 414 * @dev: pointer to netdevice (NULL => subscribe from 'all' CAN devices list) 415 * @can_id: CAN identifier (see description) 416 * @mask: CAN mask (see description) 417 * @func: callback function on filter match 418 * @data: returned parameter for callback function 419 * @ident: string for calling module identification 420 * @sk: socket pointer (might be NULL) 421 * 422 * Description: 423 * Invokes the callback function with the received sk_buff and the given 424 * parameter 'data' on a matching receive filter. A filter matches, when 425 * 426 * <received_can_id> & mask == can_id & mask 427 * 428 * The filter can be inverted (CAN_INV_FILTER bit set in can_id) or it can 429 * filter for error message frames (CAN_ERR_FLAG bit set in mask). 430 * 431 * The provided pointer to the sk_buff is guaranteed to be valid as long as 432 * the callback function is running. The callback function must *not* free 433 * the given sk_buff while processing it's task. When the given sk_buff is 434 * needed after the end of the callback function it must be cloned inside 435 * the callback function with skb_clone(). 436 * 437 * Return: 438 * 0 on success 439 * -ENOMEM on missing cache mem to create subscription entry 440 * -ENODEV unknown device 441 */ 442 int can_rx_register(struct net *net, struct net_device *dev, canid_t can_id, 443 canid_t mask, void (*func)(struct sk_buff *, void *), 444 void *data, char *ident, struct sock *sk) 445 { 446 struct receiver *rcv; 447 struct hlist_head *rcv_list; 448 struct can_dev_rcv_lists *dev_rcv_lists; 449 struct can_rcv_lists_stats *rcv_lists_stats = net->can.rcv_lists_stats; 450 int err = 0; 451 452 /* insert new receiver (dev,canid,mask) -> (func,data) */ 453 454 if (dev && dev->type != ARPHRD_CAN) 455 return -ENODEV; 456 457 if (dev && !net_eq(net, dev_net(dev))) 458 return -ENODEV; 459 460 rcv = kmem_cache_alloc(rcv_cache, GFP_KERNEL); 461 if (!rcv) 462 return -ENOMEM; 463 464 spin_lock_bh(&net->can.rcvlists_lock); 465 466 dev_rcv_lists = can_dev_rcv_lists_find(net, dev); 467 rcv_list = can_rcv_list_find(&can_id, &mask, dev_rcv_lists); 468 469 rcv->can_id = can_id; 470 rcv->mask = mask; 471 rcv->matches = 0; 472 rcv->func = func; 473 rcv->data = data; 474 rcv->ident = ident; 475 rcv->sk = sk; 476 477 hlist_add_head_rcu(&rcv->list, rcv_list); 478 dev_rcv_lists->entries++; 479 480 rcv_lists_stats->rcv_entries++; 481 rcv_lists_stats->rcv_entries_max = max(rcv_lists_stats->rcv_entries_max, 482 rcv_lists_stats->rcv_entries); 483 spin_unlock_bh(&net->can.rcvlists_lock); 484 485 return err; 486 } 487 EXPORT_SYMBOL(can_rx_register); 488 489 /* can_rx_delete_receiver - rcu callback for single receiver entry removal */ 490 static void can_rx_delete_receiver(struct rcu_head *rp) 491 { 492 struct receiver *rcv = container_of(rp, struct receiver, rcu); 493 struct sock *sk = rcv->sk; 494 495 kmem_cache_free(rcv_cache, rcv); 496 if (sk) 497 sock_put(sk); 498 } 499 500 /** 501 * can_rx_unregister - unsubscribe CAN frames from a specific interface 502 * @net: the applicable net namespace 503 * @dev: pointer to netdevice (NULL => unsubscribe from 'all' CAN devices list) 504 * @can_id: CAN identifier 505 * @mask: CAN mask 506 * @func: callback function on filter match 507 * @data: returned parameter for callback function 508 * 509 * Description: 510 * Removes subscription entry depending on given (subscription) values. 511 */ 512 void can_rx_unregister(struct net *net, struct net_device *dev, canid_t can_id, 513 canid_t mask, void (*func)(struct sk_buff *, void *), 514 void *data) 515 { 516 struct receiver *rcv = NULL; 517 struct hlist_head *rcv_list; 518 struct can_rcv_lists_stats *rcv_lists_stats = net->can.rcv_lists_stats; 519 struct can_dev_rcv_lists *dev_rcv_lists; 520 521 if (dev && dev->type != ARPHRD_CAN) 522 return; 523 524 if (dev && !net_eq(net, dev_net(dev))) 525 return; 526 527 spin_lock_bh(&net->can.rcvlists_lock); 528 529 dev_rcv_lists = can_dev_rcv_lists_find(net, dev); 530 rcv_list = can_rcv_list_find(&can_id, &mask, dev_rcv_lists); 531 532 /* Search the receiver list for the item to delete. This should 533 * exist, since no receiver may be unregistered that hasn't 534 * been registered before. 535 */ 536 hlist_for_each_entry_rcu(rcv, rcv_list, list) { 537 if (rcv->can_id == can_id && rcv->mask == mask && 538 rcv->func == func && rcv->data == data) 539 break; 540 } 541 542 /* Check for bugs in CAN protocol implementations using af_can.c: 543 * 'rcv' will be NULL if no matching list item was found for removal. 544 * As this case may potentially happen when closing a socket while 545 * the notifier for removing the CAN netdev is running we just print 546 * a warning here. 547 */ 548 if (!rcv) { 549 pr_warn("can: receive list entry not found for dev %s, id %03X, mask %03X\n", 550 DNAME(dev), can_id, mask); 551 goto out; 552 } 553 554 hlist_del_rcu(&rcv->list); 555 dev_rcv_lists->entries--; 556 557 if (rcv_lists_stats->rcv_entries > 0) 558 rcv_lists_stats->rcv_entries--; 559 560 out: 561 spin_unlock_bh(&net->can.rcvlists_lock); 562 563 /* schedule the receiver item for deletion */ 564 if (rcv) { 565 if (rcv->sk) 566 sock_hold(rcv->sk); 567 call_rcu(&rcv->rcu, can_rx_delete_receiver); 568 } 569 } 570 EXPORT_SYMBOL(can_rx_unregister); 571 572 static inline void deliver(struct sk_buff *skb, struct receiver *rcv) 573 { 574 rcv->func(skb, rcv->data); 575 rcv->matches++; 576 } 577 578 static int can_rcv_filter(struct can_dev_rcv_lists *dev_rcv_lists, struct sk_buff *skb) 579 { 580 struct receiver *rcv; 581 int matches = 0; 582 struct can_frame *cf = (struct can_frame *)skb->data; 583 canid_t can_id = cf->can_id; 584 585 if (dev_rcv_lists->entries == 0) 586 return 0; 587 588 if (can_id & CAN_ERR_FLAG) { 589 /* check for error message frame entries only */ 590 hlist_for_each_entry_rcu(rcv, &dev_rcv_lists->rx[RX_ERR], list) { 591 if (can_id & rcv->mask) { 592 deliver(skb, rcv); 593 matches++; 594 } 595 } 596 return matches; 597 } 598 599 /* check for unfiltered entries */ 600 hlist_for_each_entry_rcu(rcv, &dev_rcv_lists->rx[RX_ALL], list) { 601 deliver(skb, rcv); 602 matches++; 603 } 604 605 /* check for can_id/mask entries */ 606 hlist_for_each_entry_rcu(rcv, &dev_rcv_lists->rx[RX_FIL], list) { 607 if ((can_id & rcv->mask) == rcv->can_id) { 608 deliver(skb, rcv); 609 matches++; 610 } 611 } 612 613 /* check for inverted can_id/mask entries */ 614 hlist_for_each_entry_rcu(rcv, &dev_rcv_lists->rx[RX_INV], list) { 615 if ((can_id & rcv->mask) != rcv->can_id) { 616 deliver(skb, rcv); 617 matches++; 618 } 619 } 620 621 /* check filterlists for single non-RTR can_ids */ 622 if (can_id & CAN_RTR_FLAG) 623 return matches; 624 625 if (can_id & CAN_EFF_FLAG) { 626 hlist_for_each_entry_rcu(rcv, &dev_rcv_lists->rx_eff[effhash(can_id)], list) { 627 if (rcv->can_id == can_id) { 628 deliver(skb, rcv); 629 matches++; 630 } 631 } 632 } else { 633 can_id &= CAN_SFF_MASK; 634 hlist_for_each_entry_rcu(rcv, &dev_rcv_lists->rx_sff[can_id], list) { 635 deliver(skb, rcv); 636 matches++; 637 } 638 } 639 640 return matches; 641 } 642 643 static void can_receive(struct sk_buff *skb, struct net_device *dev) 644 { 645 struct can_dev_rcv_lists *dev_rcv_lists; 646 struct net *net = dev_net(dev); 647 struct can_pkg_stats *pkg_stats = net->can.pkg_stats; 648 int matches; 649 650 /* update statistics */ 651 pkg_stats->rx_frames++; 652 pkg_stats->rx_frames_delta++; 653 654 /* create non-zero unique skb identifier together with *skb */ 655 while (!(can_skb_prv(skb)->skbcnt)) 656 can_skb_prv(skb)->skbcnt = atomic_inc_return(&skbcounter); 657 658 rcu_read_lock(); 659 660 /* deliver the packet to sockets listening on all devices */ 661 matches = can_rcv_filter(net->can.rx_alldev_list, skb); 662 663 /* find receive list for this device */ 664 dev_rcv_lists = can_dev_rcv_lists_find(net, dev); 665 matches += can_rcv_filter(dev_rcv_lists, skb); 666 667 rcu_read_unlock(); 668 669 /* consume the skbuff allocated by the netdevice driver */ 670 consume_skb(skb); 671 672 if (matches > 0) { 673 pkg_stats->matches++; 674 pkg_stats->matches_delta++; 675 } 676 } 677 678 static int can_rcv(struct sk_buff *skb, struct net_device *dev, 679 struct packet_type *pt, struct net_device *orig_dev) 680 { 681 struct canfd_frame *cfd = (struct canfd_frame *)skb->data; 682 683 if (unlikely(dev->type != ARPHRD_CAN || skb->len != CAN_MTU)) { 684 pr_warn_once("PF_CAN: dropped non conform CAN skbuff: dev type %d, len %d\n", 685 dev->type, skb->len); 686 goto free_skb; 687 } 688 689 /* This check is made separately since cfd->len would be uninitialized if skb->len = 0. */ 690 if (unlikely(cfd->len > CAN_MAX_DLEN)) { 691 pr_warn_once("PF_CAN: dropped non conform CAN skbuff: dev type %d, len %d, datalen %d\n", 692 dev->type, skb->len, cfd->len); 693 goto free_skb; 694 } 695 696 can_receive(skb, dev); 697 return NET_RX_SUCCESS; 698 699 free_skb: 700 kfree_skb(skb); 701 return NET_RX_DROP; 702 } 703 704 static int canfd_rcv(struct sk_buff *skb, struct net_device *dev, 705 struct packet_type *pt, struct net_device *orig_dev) 706 { 707 struct canfd_frame *cfd = (struct canfd_frame *)skb->data; 708 709 if (unlikely(dev->type != ARPHRD_CAN || skb->len != CANFD_MTU)) { 710 pr_warn_once("PF_CAN: dropped non conform CAN FD skbuff: dev type %d, len %d\n", 711 dev->type, skb->len); 712 goto free_skb; 713 } 714 715 /* This check is made separately since cfd->len would be uninitialized if skb->len = 0. */ 716 if (unlikely(cfd->len > CANFD_MAX_DLEN)) { 717 pr_warn_once("PF_CAN: dropped non conform CAN FD skbuff: dev type %d, len %d, datalen %d\n", 718 dev->type, skb->len, cfd->len); 719 goto free_skb; 720 } 721 722 can_receive(skb, dev); 723 return NET_RX_SUCCESS; 724 725 free_skb: 726 kfree_skb(skb); 727 return NET_RX_DROP; 728 } 729 730 /* af_can protocol functions */ 731 732 /** 733 * can_proto_register - register CAN transport protocol 734 * @cp: pointer to CAN protocol structure 735 * 736 * Return: 737 * 0 on success 738 * -EINVAL invalid (out of range) protocol number 739 * -EBUSY protocol already in use 740 * -ENOBUF if proto_register() fails 741 */ 742 int can_proto_register(const struct can_proto *cp) 743 { 744 int proto = cp->protocol; 745 int err = 0; 746 747 if (proto < 0 || proto >= CAN_NPROTO) { 748 pr_err("can: protocol number %d out of range\n", proto); 749 return -EINVAL; 750 } 751 752 err = proto_register(cp->prot, 0); 753 if (err < 0) 754 return err; 755 756 mutex_lock(&proto_tab_lock); 757 758 if (rcu_access_pointer(proto_tab[proto])) { 759 pr_err("can: protocol %d already registered\n", proto); 760 err = -EBUSY; 761 } else { 762 RCU_INIT_POINTER(proto_tab[proto], cp); 763 } 764 765 mutex_unlock(&proto_tab_lock); 766 767 if (err < 0) 768 proto_unregister(cp->prot); 769 770 return err; 771 } 772 EXPORT_SYMBOL(can_proto_register); 773 774 /** 775 * can_proto_unregister - unregister CAN transport protocol 776 * @cp: pointer to CAN protocol structure 777 */ 778 void can_proto_unregister(const struct can_proto *cp) 779 { 780 int proto = cp->protocol; 781 782 mutex_lock(&proto_tab_lock); 783 BUG_ON(rcu_access_pointer(proto_tab[proto]) != cp); 784 RCU_INIT_POINTER(proto_tab[proto], NULL); 785 mutex_unlock(&proto_tab_lock); 786 787 synchronize_rcu(); 788 789 proto_unregister(cp->prot); 790 } 791 EXPORT_SYMBOL(can_proto_unregister); 792 793 static int can_pernet_init(struct net *net) 794 { 795 spin_lock_init(&net->can.rcvlists_lock); 796 net->can.rx_alldev_list = 797 kzalloc(sizeof(*net->can.rx_alldev_list), GFP_KERNEL); 798 if (!net->can.rx_alldev_list) 799 goto out; 800 net->can.pkg_stats = kzalloc(sizeof(*net->can.pkg_stats), GFP_KERNEL); 801 if (!net->can.pkg_stats) 802 goto out_free_rx_alldev_list; 803 net->can.rcv_lists_stats = kzalloc(sizeof(*net->can.rcv_lists_stats), GFP_KERNEL); 804 if (!net->can.rcv_lists_stats) 805 goto out_free_pkg_stats; 806 807 if (IS_ENABLED(CONFIG_PROC_FS)) { 808 /* the statistics are updated every second (timer triggered) */ 809 if (stats_timer) { 810 timer_setup(&net->can.stattimer, can_stat_update, 811 0); 812 mod_timer(&net->can.stattimer, 813 round_jiffies(jiffies + HZ)); 814 } 815 net->can.pkg_stats->jiffies_init = jiffies; 816 can_init_proc(net); 817 } 818 819 return 0; 820 821 out_free_pkg_stats: 822 kfree(net->can.pkg_stats); 823 out_free_rx_alldev_list: 824 kfree(net->can.rx_alldev_list); 825 out: 826 return -ENOMEM; 827 } 828 829 static void can_pernet_exit(struct net *net) 830 { 831 if (IS_ENABLED(CONFIG_PROC_FS)) { 832 can_remove_proc(net); 833 if (stats_timer) 834 del_timer_sync(&net->can.stattimer); 835 } 836 837 kfree(net->can.rx_alldev_list); 838 kfree(net->can.pkg_stats); 839 kfree(net->can.rcv_lists_stats); 840 } 841 842 /* af_can module init/exit functions */ 843 844 static struct packet_type can_packet __read_mostly = { 845 .type = cpu_to_be16(ETH_P_CAN), 846 .func = can_rcv, 847 }; 848 849 static struct packet_type canfd_packet __read_mostly = { 850 .type = cpu_to_be16(ETH_P_CANFD), 851 .func = canfd_rcv, 852 }; 853 854 static const struct net_proto_family can_family_ops = { 855 .family = PF_CAN, 856 .create = can_create, 857 .owner = THIS_MODULE, 858 }; 859 860 static struct pernet_operations can_pernet_ops __read_mostly = { 861 .init = can_pernet_init, 862 .exit = can_pernet_exit, 863 }; 864 865 static __init int can_init(void) 866 { 867 int err; 868 869 /* check for correct padding to be able to use the structs similarly */ 870 BUILD_BUG_ON(offsetof(struct can_frame, len) != 871 offsetof(struct canfd_frame, len) || 872 offsetof(struct can_frame, data) != 873 offsetof(struct canfd_frame, data)); 874 875 pr_info("can: controller area network core\n"); 876 877 rcv_cache = kmem_cache_create("can_receiver", sizeof(struct receiver), 878 0, 0, NULL); 879 if (!rcv_cache) 880 return -ENOMEM; 881 882 err = register_pernet_subsys(&can_pernet_ops); 883 if (err) 884 goto out_pernet; 885 886 /* protocol register */ 887 err = sock_register(&can_family_ops); 888 if (err) 889 goto out_sock; 890 891 dev_add_pack(&can_packet); 892 dev_add_pack(&canfd_packet); 893 894 return 0; 895 896 out_sock: 897 unregister_pernet_subsys(&can_pernet_ops); 898 out_pernet: 899 kmem_cache_destroy(rcv_cache); 900 901 return err; 902 } 903 904 static __exit void can_exit(void) 905 { 906 /* protocol unregister */ 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