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 sock->sk = NULL; 175 } else { 176 sock_prot_inuse_add(net, sk->sk_prot, 1); 177 } 178 179 errout: 180 can_put_proto(cp); 181 return err; 182 } 183 184 /* af_can tx path */ 185 186 /** 187 * can_send - transmit a CAN frame (optional with local loopback) 188 * @skb: pointer to socket buffer with CAN frame in data section 189 * @loop: loopback for listeners on local CAN sockets (recommended default!) 190 * 191 * Due to the loopback this routine must not be called from hardirq context. 192 * 193 * Return: 194 * 0 on success 195 * -ENETDOWN when the selected interface is down 196 * -ENOBUFS on full driver queue (see net_xmit_errno()) 197 * -ENOMEM when local loopback failed at calling skb_clone() 198 * -EPERM when trying to send on a non-CAN interface 199 * -EMSGSIZE CAN frame size is bigger than CAN interface MTU 200 * -EINVAL when the skb->data does not contain a valid CAN frame 201 */ 202 int can_send(struct sk_buff *skb, int loop) 203 { 204 struct sk_buff *newskb = NULL; 205 struct can_pkg_stats *pkg_stats = dev_net(skb->dev)->can.pkg_stats; 206 int err = -EINVAL; 207 208 if (can_is_canxl_skb(skb)) { 209 skb->protocol = htons(ETH_P_CANXL); 210 } else if (can_is_can_skb(skb)) { 211 skb->protocol = htons(ETH_P_CAN); 212 } else if (can_is_canfd_skb(skb)) { 213 struct canfd_frame *cfd = (struct canfd_frame *)skb->data; 214 215 skb->protocol = htons(ETH_P_CANFD); 216 217 /* set CAN FD flag for CAN FD frames by default */ 218 cfd->flags |= CANFD_FDF; 219 } else { 220 goto inval_skb; 221 } 222 223 /* Make sure the CAN frame can pass the selected CAN netdevice. */ 224 if (unlikely(skb->len > READ_ONCE(skb->dev->mtu))) { 225 err = -EMSGSIZE; 226 goto inval_skb; 227 } 228 229 if (unlikely(skb->dev->type != ARPHRD_CAN)) { 230 err = -EPERM; 231 goto inval_skb; 232 } 233 234 if (unlikely(!(skb->dev->flags & IFF_UP))) { 235 err = -ENETDOWN; 236 goto inval_skb; 237 } 238 239 skb->ip_summed = CHECKSUM_UNNECESSARY; 240 241 skb_reset_mac_header(skb); 242 skb_reset_network_header(skb); 243 skb_reset_transport_header(skb); 244 245 if (loop) { 246 /* local loopback of sent CAN frames */ 247 248 /* indication for the CAN driver: do loopback */ 249 skb->pkt_type = PACKET_LOOPBACK; 250 251 /* The reference to the originating sock may be required 252 * by the receiving socket to check whether the frame is 253 * its own. Example: can_raw sockopt CAN_RAW_RECV_OWN_MSGS 254 * Therefore we have to ensure that skb->sk remains the 255 * reference to the originating sock by restoring skb->sk 256 * after each skb_clone() or skb_orphan() usage. 257 */ 258 259 if (!(skb->dev->flags & IFF_ECHO)) { 260 /* If the interface is not capable to do loopback 261 * itself, we do it here. 262 */ 263 newskb = skb_clone(skb, GFP_ATOMIC); 264 if (!newskb) { 265 kfree_skb(skb); 266 return -ENOMEM; 267 } 268 269 can_skb_set_owner(newskb, skb->sk); 270 newskb->ip_summed = CHECKSUM_UNNECESSARY; 271 newskb->pkt_type = PACKET_BROADCAST; 272 } 273 } else { 274 /* indication for the CAN driver: no loopback required */ 275 skb->pkt_type = PACKET_HOST; 276 } 277 278 /* send to netdevice */ 279 err = dev_queue_xmit(skb); 280 if (err > 0) 281 err = net_xmit_errno(err); 282 283 if (err) { 284 kfree_skb(newskb); 285 return err; 286 } 287 288 if (newskb) 289 netif_rx(newskb); 290 291 /* update statistics */ 292 atomic_long_inc(&pkg_stats->tx_frames); 293 atomic_long_inc(&pkg_stats->tx_frames_delta); 294 295 return 0; 296 297 inval_skb: 298 kfree_skb(skb); 299 return err; 300 } 301 EXPORT_SYMBOL(can_send); 302 303 /* af_can rx path */ 304 305 static struct can_dev_rcv_lists *can_dev_rcv_lists_find(struct net *net, 306 struct net_device *dev) 307 { 308 if (dev) { 309 struct can_ml_priv *can_ml = can_get_ml_priv(dev); 310 return &can_ml->dev_rcv_lists; 311 } else { 312 return net->can.rx_alldev_list; 313 } 314 } 315 316 /** 317 * effhash - hash function for 29 bit CAN identifier reduction 318 * @can_id: 29 bit CAN identifier 319 * 320 * Description: 321 * To reduce the linear traversal in one linked list of _single_ EFF CAN 322 * frame subscriptions the 29 bit identifier is mapped to 10 bits. 323 * (see CAN_EFF_RCV_HASH_BITS definition) 324 * 325 * Return: 326 * Hash value from 0x000 - 0x3FF ( enforced by CAN_EFF_RCV_HASH_BITS mask ) 327 */ 328 static unsigned int effhash(canid_t can_id) 329 { 330 unsigned int hash; 331 332 hash = can_id; 333 hash ^= can_id >> CAN_EFF_RCV_HASH_BITS; 334 hash ^= can_id >> (2 * CAN_EFF_RCV_HASH_BITS); 335 336 return hash & ((1 << CAN_EFF_RCV_HASH_BITS) - 1); 337 } 338 339 /** 340 * can_rcv_list_find - determine optimal filterlist inside device filter struct 341 * @can_id: pointer to CAN identifier of a given can_filter 342 * @mask: pointer to CAN mask of a given can_filter 343 * @dev_rcv_lists: pointer to the device filter struct 344 * 345 * Description: 346 * Returns the optimal filterlist to reduce the filter handling in the 347 * receive path. This function is called by service functions that need 348 * to register or unregister a can_filter in the filter lists. 349 * 350 * A filter matches in general, when 351 * 352 * <received_can_id> & mask == can_id & mask 353 * 354 * so every bit set in the mask (even CAN_EFF_FLAG, CAN_RTR_FLAG) describe 355 * relevant bits for the filter. 356 * 357 * The filter can be inverted (CAN_INV_FILTER bit set in can_id) or it can 358 * filter for error messages (CAN_ERR_FLAG bit set in mask). For error msg 359 * frames there is a special filterlist and a special rx path filter handling. 360 * 361 * Return: 362 * Pointer to optimal filterlist for the given can_id/mask pair. 363 * Consistency checked mask. 364 * Reduced can_id to have a preprocessed filter compare value. 365 */ 366 static struct hlist_head *can_rcv_list_find(canid_t *can_id, canid_t *mask, 367 struct can_dev_rcv_lists *dev_rcv_lists) 368 { 369 canid_t inv = *can_id & CAN_INV_FILTER; /* save flag before masking */ 370 371 /* filter for error message frames in extra filterlist */ 372 if (*mask & CAN_ERR_FLAG) { 373 /* clear CAN_ERR_FLAG in filter entry */ 374 *mask &= CAN_ERR_MASK; 375 return &dev_rcv_lists->rx[RX_ERR]; 376 } 377 378 /* with cleared CAN_ERR_FLAG we have a simple mask/value filterpair */ 379 380 #define CAN_EFF_RTR_FLAGS (CAN_EFF_FLAG | CAN_RTR_FLAG) 381 382 /* ensure valid values in can_mask for 'SFF only' frame filtering */ 383 if ((*mask & CAN_EFF_FLAG) && !(*can_id & CAN_EFF_FLAG)) 384 *mask &= (CAN_SFF_MASK | CAN_EFF_RTR_FLAGS); 385 386 /* reduce condition testing at receive time */ 387 *can_id &= *mask; 388 389 /* inverse can_id/can_mask filter */ 390 if (inv) 391 return &dev_rcv_lists->rx[RX_INV]; 392 393 /* mask == 0 => no condition testing at receive time */ 394 if (!(*mask)) 395 return &dev_rcv_lists->rx[RX_ALL]; 396 397 /* extra filterlists for the subscription of a single non-RTR can_id */ 398 if (((*mask & CAN_EFF_RTR_FLAGS) == CAN_EFF_RTR_FLAGS) && 399 !(*can_id & CAN_RTR_FLAG)) { 400 if (*can_id & CAN_EFF_FLAG) { 401 if (*mask == (CAN_EFF_MASK | CAN_EFF_RTR_FLAGS)) 402 return &dev_rcv_lists->rx_eff[effhash(*can_id)]; 403 } else { 404 if (*mask == (CAN_SFF_MASK | CAN_EFF_RTR_FLAGS)) 405 return &dev_rcv_lists->rx_sff[*can_id]; 406 } 407 } 408 409 /* default: filter via can_id/can_mask */ 410 return &dev_rcv_lists->rx[RX_FIL]; 411 } 412 413 /** 414 * can_rx_register - subscribe CAN frames from a specific interface 415 * @net: the applicable net namespace 416 * @dev: pointer to netdevice (NULL => subscribe from 'all' CAN devices list) 417 * @can_id: CAN identifier (see description) 418 * @mask: CAN mask (see description) 419 * @func: callback function on filter match 420 * @data: returned parameter for callback function 421 * @ident: string for calling module identification 422 * @sk: socket pointer (might be NULL) 423 * 424 * Description: 425 * Invokes the callback function with the received sk_buff and the given 426 * parameter 'data' on a matching receive filter. A filter matches, when 427 * 428 * <received_can_id> & mask == can_id & mask 429 * 430 * The filter can be inverted (CAN_INV_FILTER bit set in can_id) or it can 431 * filter for error message frames (CAN_ERR_FLAG bit set in mask). 432 * 433 * The provided pointer to the sk_buff is guaranteed to be valid as long as 434 * the callback function is running. The callback function must *not* free 435 * the given sk_buff while processing it's task. When the given sk_buff is 436 * needed after the end of the callback function it must be cloned inside 437 * the callback function with skb_clone(). 438 * 439 * Return: 440 * 0 on success 441 * -ENOMEM on missing cache mem to create subscription entry 442 * -ENODEV unknown device 443 */ 444 int can_rx_register(struct net *net, struct net_device *dev, canid_t can_id, 445 canid_t mask, void (*func)(struct sk_buff *, void *), 446 void *data, char *ident, struct sock *sk) 447 { 448 struct receiver *rcv; 449 struct hlist_head *rcv_list; 450 struct can_dev_rcv_lists *dev_rcv_lists; 451 struct can_rcv_lists_stats *rcv_lists_stats = net->can.rcv_lists_stats; 452 453 /* insert new receiver (dev,canid,mask) -> (func,data) */ 454 455 if (dev && (dev->type != ARPHRD_CAN || !can_get_ml_priv(dev))) 456 return -ENODEV; 457 458 if (dev && !net_eq(net, dev_net(dev))) 459 return -ENODEV; 460 461 rcv = kmem_cache_alloc(rcv_cache, GFP_KERNEL); 462 if (!rcv) 463 return -ENOMEM; 464 465 spin_lock_bh(&net->can.rcvlists_lock); 466 467 dev_rcv_lists = can_dev_rcv_lists_find(net, dev); 468 rcv_list = can_rcv_list_find(&can_id, &mask, dev_rcv_lists); 469 470 rcv->can_id = can_id; 471 rcv->mask = mask; 472 rcv->matches = 0; 473 rcv->func = func; 474 rcv->data = data; 475 rcv->ident = ident; 476 rcv->sk = sk; 477 478 hlist_add_head_rcu(&rcv->list, rcv_list); 479 dev_rcv_lists->entries++; 480 481 rcv_lists_stats->rcv_entries++; 482 rcv_lists_stats->rcv_entries_max = max(rcv_lists_stats->rcv_entries_max, 483 rcv_lists_stats->rcv_entries); 484 spin_unlock_bh(&net->can.rcvlists_lock); 485 486 return 0; 487 } 488 EXPORT_SYMBOL(can_rx_register); 489 490 /* can_rx_delete_receiver - rcu callback for single receiver entry removal */ 491 static void can_rx_delete_receiver(struct rcu_head *rp) 492 { 493 struct receiver *rcv = container_of(rp, struct receiver, rcu); 494 struct sock *sk = rcv->sk; 495 496 kmem_cache_free(rcv_cache, rcv); 497 if (sk) 498 sock_put(sk); 499 } 500 501 /** 502 * can_rx_unregister - unsubscribe CAN frames from a specific interface 503 * @net: the applicable net namespace 504 * @dev: pointer to netdevice (NULL => unsubscribe from 'all' CAN devices list) 505 * @can_id: CAN identifier 506 * @mask: CAN mask 507 * @func: callback function on filter match 508 * @data: returned parameter for callback function 509 * 510 * Description: 511 * Removes subscription entry depending on given (subscription) values. 512 */ 513 void can_rx_unregister(struct net *net, struct net_device *dev, canid_t can_id, 514 canid_t mask, void (*func)(struct sk_buff *, void *), 515 void *data) 516 { 517 struct receiver *rcv = NULL; 518 struct hlist_head *rcv_list; 519 struct can_rcv_lists_stats *rcv_lists_stats = net->can.rcv_lists_stats; 520 struct can_dev_rcv_lists *dev_rcv_lists; 521 522 if (dev && dev->type != ARPHRD_CAN) 523 return; 524 525 if (dev && !net_eq(net, dev_net(dev))) 526 return; 527 528 spin_lock_bh(&net->can.rcvlists_lock); 529 530 dev_rcv_lists = can_dev_rcv_lists_find(net, dev); 531 rcv_list = can_rcv_list_find(&can_id, &mask, dev_rcv_lists); 532 533 /* Search the receiver list for the item to delete. This should 534 * exist, since no receiver may be unregistered that hasn't 535 * been registered before. 536 */ 537 hlist_for_each_entry_rcu(rcv, rcv_list, list) { 538 if (rcv->can_id == can_id && rcv->mask == mask && 539 rcv->func == func && rcv->data == data) 540 break; 541 } 542 543 /* Check for bugs in CAN protocol implementations using af_can.c: 544 * 'rcv' will be NULL if no matching list item was found for removal. 545 * As this case may potentially happen when closing a socket while 546 * the notifier for removing the CAN netdev is running we just print 547 * a warning here. 548 */ 549 if (!rcv) { 550 pr_warn("can: receive list entry not found for dev %s, id %03X, mask %03X\n", 551 DNAME(dev), can_id, mask); 552 goto out; 553 } 554 555 hlist_del_rcu(&rcv->list); 556 dev_rcv_lists->entries--; 557 558 if (rcv_lists_stats->rcv_entries > 0) 559 rcv_lists_stats->rcv_entries--; 560 561 out: 562 spin_unlock_bh(&net->can.rcvlists_lock); 563 564 /* schedule the receiver item for deletion */ 565 if (rcv) { 566 if (rcv->sk) 567 sock_hold(rcv->sk); 568 call_rcu(&rcv->rcu, can_rx_delete_receiver); 569 } 570 } 571 EXPORT_SYMBOL(can_rx_unregister); 572 573 static inline void deliver(struct sk_buff *skb, struct receiver *rcv) 574 { 575 rcv->func(skb, rcv->data); 576 rcv->matches++; 577 } 578 579 static int can_rcv_filter(struct can_dev_rcv_lists *dev_rcv_lists, struct sk_buff *skb) 580 { 581 struct receiver *rcv; 582 int matches = 0; 583 struct can_frame *cf = (struct can_frame *)skb->data; 584 canid_t can_id = cf->can_id; 585 586 if (dev_rcv_lists->entries == 0) 587 return 0; 588 589 if (can_id & CAN_ERR_FLAG) { 590 /* check for error message frame entries only */ 591 hlist_for_each_entry_rcu(rcv, &dev_rcv_lists->rx[RX_ERR], list) { 592 if (can_id & rcv->mask) { 593 deliver(skb, rcv); 594 matches++; 595 } 596 } 597 return matches; 598 } 599 600 /* check for unfiltered entries */ 601 hlist_for_each_entry_rcu(rcv, &dev_rcv_lists->rx[RX_ALL], list) { 602 deliver(skb, rcv); 603 matches++; 604 } 605 606 /* check for can_id/mask entries */ 607 hlist_for_each_entry_rcu(rcv, &dev_rcv_lists->rx[RX_FIL], list) { 608 if ((can_id & rcv->mask) == rcv->can_id) { 609 deliver(skb, rcv); 610 matches++; 611 } 612 } 613 614 /* check for inverted can_id/mask entries */ 615 hlist_for_each_entry_rcu(rcv, &dev_rcv_lists->rx[RX_INV], list) { 616 if ((can_id & rcv->mask) != rcv->can_id) { 617 deliver(skb, rcv); 618 matches++; 619 } 620 } 621 622 /* check filterlists for single non-RTR can_ids */ 623 if (can_id & CAN_RTR_FLAG) 624 return matches; 625 626 if (can_id & CAN_EFF_FLAG) { 627 hlist_for_each_entry_rcu(rcv, &dev_rcv_lists->rx_eff[effhash(can_id)], list) { 628 if (rcv->can_id == can_id) { 629 deliver(skb, rcv); 630 matches++; 631 } 632 } 633 } else { 634 can_id &= CAN_SFF_MASK; 635 hlist_for_each_entry_rcu(rcv, &dev_rcv_lists->rx_sff[can_id], list) { 636 deliver(skb, rcv); 637 matches++; 638 } 639 } 640 641 return matches; 642 } 643 644 void can_set_skb_uid(struct sk_buff *skb) 645 { 646 /* create non-zero unique skb identifier together with *skb */ 647 while (!(skb->hash)) 648 skb->hash = atomic_inc_return(&skbcounter); 649 650 skb->sw_hash = 1; 651 } 652 EXPORT_SYMBOL(can_set_skb_uid); 653 654 static void can_receive(struct sk_buff *skb, struct net_device *dev) 655 { 656 struct can_dev_rcv_lists *dev_rcv_lists; 657 struct net *net = dev_net(dev); 658 struct can_pkg_stats *pkg_stats = net->can.pkg_stats; 659 int matches; 660 661 /* update statistics */ 662 atomic_long_inc(&pkg_stats->rx_frames); 663 atomic_long_inc(&pkg_stats->rx_frames_delta); 664 665 can_set_skb_uid(skb); 666 667 rcu_read_lock(); 668 669 /* deliver the packet to sockets listening on all devices */ 670 matches = can_rcv_filter(net->can.rx_alldev_list, skb); 671 672 /* find receive list for this device */ 673 dev_rcv_lists = can_dev_rcv_lists_find(net, dev); 674 matches += can_rcv_filter(dev_rcv_lists, skb); 675 676 rcu_read_unlock(); 677 678 /* consume the skbuff allocated by the netdevice driver */ 679 consume_skb(skb); 680 681 if (matches > 0) { 682 atomic_long_inc(&pkg_stats->matches); 683 atomic_long_inc(&pkg_stats->matches_delta); 684 } 685 } 686 687 static int can_rcv(struct sk_buff *skb, struct net_device *dev, 688 struct packet_type *pt, struct net_device *orig_dev) 689 { 690 if (unlikely(dev->type != ARPHRD_CAN || !can_get_ml_priv(dev) || 691 !can_skb_ext_find(skb) || !can_is_can_skb(skb))) { 692 pr_warn_once("PF_CAN: dropped non conform CAN skbuff: dev type %d, len %d\n", 693 dev->type, skb->len); 694 695 kfree_skb_reason(skb, SKB_DROP_REASON_CAN_RX_INVALID_FRAME); 696 return NET_RX_DROP; 697 } 698 699 can_receive(skb, dev); 700 return NET_RX_SUCCESS; 701 } 702 703 static int canfd_rcv(struct sk_buff *skb, struct net_device *dev, 704 struct packet_type *pt, struct net_device *orig_dev) 705 { 706 if (unlikely(dev->type != ARPHRD_CAN || !can_get_ml_priv(dev) || 707 !can_skb_ext_find(skb) || !can_is_canfd_skb(skb))) { 708 pr_warn_once("PF_CAN: dropped non conform CAN FD skbuff: dev type %d, len %d\n", 709 dev->type, skb->len); 710 711 kfree_skb_reason(skb, SKB_DROP_REASON_CANFD_RX_INVALID_FRAME); 712 return NET_RX_DROP; 713 } 714 715 can_receive(skb, dev); 716 return NET_RX_SUCCESS; 717 } 718 719 static int canxl_rcv(struct sk_buff *skb, struct net_device *dev, 720 struct packet_type *pt, struct net_device *orig_dev) 721 { 722 if (unlikely(dev->type != ARPHRD_CAN || !can_get_ml_priv(dev) || 723 !can_skb_ext_find(skb) || !can_is_canxl_skb(skb))) { 724 pr_warn_once("PF_CAN: dropped non conform CAN XL skbuff: dev type %d, len %d\n", 725 dev->type, skb->len); 726 727 kfree_skb_reason(skb, SKB_DROP_REASON_CANXL_RX_INVALID_FRAME); 728 return NET_RX_DROP; 729 } 730 731 can_receive(skb, dev); 732 return NET_RX_SUCCESS; 733 } 734 735 /* af_can protocol functions */ 736 737 /** 738 * can_proto_register - register CAN transport protocol 739 * @cp: pointer to CAN protocol structure 740 * 741 * Return: 742 * 0 on success 743 * -EINVAL invalid (out of range) protocol number 744 * -EBUSY protocol already in use 745 * -ENOBUF if proto_register() fails 746 */ 747 int can_proto_register(const struct can_proto *cp) 748 { 749 int proto = cp->protocol; 750 int err = 0; 751 752 if (proto < 0 || proto >= CAN_NPROTO) { 753 pr_err("can: protocol number %d out of range\n", proto); 754 return -EINVAL; 755 } 756 757 err = proto_register(cp->prot, 0); 758 if (err < 0) 759 return err; 760 761 mutex_lock(&proto_tab_lock); 762 763 if (rcu_access_pointer(proto_tab[proto])) { 764 pr_err("can: protocol %d already registered\n", proto); 765 err = -EBUSY; 766 } else { 767 RCU_INIT_POINTER(proto_tab[proto], cp); 768 } 769 770 mutex_unlock(&proto_tab_lock); 771 772 if (err < 0) 773 proto_unregister(cp->prot); 774 775 return err; 776 } 777 EXPORT_SYMBOL(can_proto_register); 778 779 /** 780 * can_proto_unregister - unregister CAN transport protocol 781 * @cp: pointer to CAN protocol structure 782 */ 783 void can_proto_unregister(const struct can_proto *cp) 784 { 785 int proto = cp->protocol; 786 787 mutex_lock(&proto_tab_lock); 788 BUG_ON(rcu_access_pointer(proto_tab[proto]) != cp); 789 RCU_INIT_POINTER(proto_tab[proto], NULL); 790 mutex_unlock(&proto_tab_lock); 791 792 synchronize_rcu(); 793 794 proto_unregister(cp->prot); 795 } 796 EXPORT_SYMBOL(can_proto_unregister); 797 798 static int can_pernet_init(struct net *net) 799 { 800 spin_lock_init(&net->can.rcvlists_lock); 801 net->can.rx_alldev_list = kzalloc_obj(*net->can.rx_alldev_list, 802 GFP_KERNEL); 803 if (!net->can.rx_alldev_list) 804 goto out; 805 net->can.pkg_stats = kzalloc_obj(*net->can.pkg_stats); 806 if (!net->can.pkg_stats) 807 goto out_free_rx_alldev_list; 808 net->can.rcv_lists_stats = kzalloc_obj(*net->can.rcv_lists_stats, 809 GFP_KERNEL); 810 if (!net->can.rcv_lists_stats) 811 goto out_free_pkg_stats; 812 813 if (IS_ENABLED(CONFIG_PROC_FS)) { 814 /* the statistics are updated every second (timer triggered) */ 815 if (stats_timer) { 816 timer_setup(&net->can.stattimer, can_stat_update, 817 0); 818 mod_timer(&net->can.stattimer, 819 round_jiffies(jiffies + HZ)); 820 } 821 net->can.pkg_stats->jiffies_init = jiffies; 822 can_init_proc(net); 823 } 824 825 return 0; 826 827 out_free_pkg_stats: 828 kfree(net->can.pkg_stats); 829 out_free_rx_alldev_list: 830 kfree(net->can.rx_alldev_list); 831 out: 832 return -ENOMEM; 833 } 834 835 static void can_pernet_exit(struct net *net) 836 { 837 if (IS_ENABLED(CONFIG_PROC_FS)) { 838 can_remove_proc(net); 839 if (stats_timer) 840 timer_delete_sync(&net->can.stattimer); 841 } 842 843 kfree(net->can.rx_alldev_list); 844 kfree(net->can.pkg_stats); 845 kfree(net->can.rcv_lists_stats); 846 } 847 848 /* af_can module init/exit functions */ 849 850 static struct packet_type can_packet __read_mostly = { 851 .type = cpu_to_be16(ETH_P_CAN), 852 .func = can_rcv, 853 }; 854 855 static struct packet_type canfd_packet __read_mostly = { 856 .type = cpu_to_be16(ETH_P_CANFD), 857 .func = canfd_rcv, 858 }; 859 860 static struct packet_type canxl_packet __read_mostly = { 861 .type = cpu_to_be16(ETH_P_CANXL), 862 .func = canxl_rcv, 863 }; 864 865 static const struct net_proto_family can_family_ops = { 866 .family = PF_CAN, 867 .create = can_create, 868 .owner = THIS_MODULE, 869 }; 870 871 static struct pernet_operations can_pernet_ops __read_mostly = { 872 .init = can_pernet_init, 873 .exit = can_pernet_exit, 874 }; 875 876 static __init int can_init(void) 877 { 878 int err; 879 880 /* check for correct padding to be able to use the structs similarly */ 881 BUILD_BUG_ON(offsetof(struct can_frame, len) != 882 offsetof(struct canfd_frame, len) || 883 offsetof(struct can_frame, len) != 884 offsetof(struct canxl_frame, flags) || 885 offsetof(struct can_frame, data) != 886 offsetof(struct canfd_frame, data)); 887 888 pr_info("can: controller area network core\n"); 889 890 rcv_cache = kmem_cache_create("can_receiver", sizeof(struct receiver), 891 0, 0, NULL); 892 if (!rcv_cache) 893 return -ENOMEM; 894 895 err = register_pernet_subsys(&can_pernet_ops); 896 if (err) 897 goto out_pernet; 898 899 /* protocol register */ 900 err = sock_register(&can_family_ops); 901 if (err) 902 goto out_sock; 903 904 dev_add_pack(&can_packet); 905 dev_add_pack(&canfd_packet); 906 dev_add_pack(&canxl_packet); 907 908 return 0; 909 910 out_sock: 911 unregister_pernet_subsys(&can_pernet_ops); 912 out_pernet: 913 kmem_cache_destroy(rcv_cache); 914 915 return err; 916 } 917 918 static __exit void can_exit(void) 919 { 920 /* protocol unregister */ 921 dev_remove_pack(&canxl_packet); 922 dev_remove_pack(&canfd_packet); 923 dev_remove_pack(&can_packet); 924 sock_unregister(PF_CAN); 925 926 unregister_pernet_subsys(&can_pernet_ops); 927 928 rcu_barrier(); /* Wait for completion of call_rcu()'s */ 929 930 kmem_cache_destroy(rcv_cache); 931 } 932 933 module_init(can_init); 934 module_exit(can_exit); 935