| 1 | /* |
| 2 | * af_can.c - Protocol family CAN core module |
| 3 | * (used by different CAN protocol modules) |
| 4 | * |
| 5 | * Copyright (c) 2002-2007 Volkswagen Group Electronic Research |
| 6 | * All rights reserved. |
| 7 | * |
| 8 | * Redistribution and use in source and binary forms, with or without |
| 9 | * modification, are permitted provided that the following conditions |
| 10 | * are met: |
| 11 | * 1. Redistributions of source code must retain the above copyright |
| 12 | * notice, this list of conditions and the following disclaimer. |
| 13 | * 2. Redistributions in binary form must reproduce the above copyright |
| 14 | * notice, this list of conditions and the following disclaimer in the |
| 15 | * documentation and/or other materials provided with the distribution. |
| 16 | * 3. Neither the name of Volkswagen nor the names of its contributors |
| 17 | * may be used to endorse or promote products derived from this software |
| 18 | * without specific prior written permission. |
| 19 | * |
| 20 | * Alternatively, provided that this notice is retained in full, this |
| 21 | * software may be distributed under the terms of the GNU General |
| 22 | * Public License ("GPL") version 2, in which case the provisions of the |
| 23 | * GPL apply INSTEAD OF those given above. |
| 24 | * |
| 25 | * The provided data structures and external interfaces from this code |
| 26 | * are not restricted to be used by modules with a GPL compatible license. |
| 27 | * |
| 28 | * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
| 29 | * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
| 30 | * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
| 31 | * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT |
| 32 | * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
| 33 | * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT |
| 34 | * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| 35 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| 36 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| 37 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE |
| 38 | * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH |
| 39 | * DAMAGE. |
| 40 | * |
| 41 | */ |
| 42 | |
| 43 | #include <linux/module.h> |
| 44 | #include <linux/stddef.h> |
| 45 | #include <linux/init.h> |
| 46 | #include <linux/kmod.h> |
| 47 | #include <linux/slab.h> |
| 48 | #include <linux/list.h> |
| 49 | #include <linux/spinlock.h> |
| 50 | #include <linux/rcupdate.h> |
| 51 | #include <linux/uaccess.h> |
| 52 | #include <linux/net.h> |
| 53 | #include <linux/netdevice.h> |
| 54 | #include <linux/socket.h> |
| 55 | #include <linux/if_ether.h> |
| 56 | #include <linux/if_arp.h> |
| 57 | #include <linux/skbuff.h> |
| 58 | #include <linux/can.h> |
| 59 | #include <linux/can/core.h> |
| 60 | #include <linux/can/skb.h> |
| 61 | #include <linux/ratelimit.h> |
| 62 | #include <net/net_namespace.h> |
| 63 | #include <net/sock.h> |
| 64 | |
| 65 | #include "af_can.h" |
| 66 | |
| 67 | static __initconst const char banner[] = KERN_INFO |
| 68 | "can: controller area network core (" CAN_VERSION_STRING ")\n"; |
| 69 | |
| 70 | MODULE_DESCRIPTION("Controller Area Network PF_CAN core"); |
| 71 | MODULE_LICENSE("Dual BSD/GPL"); |
| 72 | MODULE_AUTHOR("Urs Thuermann <urs.thuermann@volkswagen.de>, " |
| 73 | "Oliver Hartkopp <oliver.hartkopp@volkswagen.de>"); |
| 74 | |
| 75 | MODULE_ALIAS_NETPROTO(PF_CAN); |
| 76 | |
| 77 | static int stats_timer __read_mostly = 1; |
| 78 | module_param(stats_timer, int, S_IRUGO); |
| 79 | MODULE_PARM_DESC(stats_timer, "enable timer for statistics (default:on)"); |
| 80 | |
| 81 | /* receive filters subscribed for 'all' CAN devices */ |
| 82 | struct dev_rcv_lists can_rx_alldev_list; |
| 83 | static DEFINE_SPINLOCK(can_rcvlists_lock); |
| 84 | |
| 85 | static struct kmem_cache *rcv_cache __read_mostly; |
| 86 | |
| 87 | /* table of registered CAN protocols */ |
| 88 | static const struct can_proto *proto_tab[CAN_NPROTO] __read_mostly; |
| 89 | static DEFINE_MUTEX(proto_tab_lock); |
| 90 | |
| 91 | struct timer_list can_stattimer; /* timer for statistics update */ |
| 92 | struct s_stats can_stats; /* packet statistics */ |
| 93 | struct s_pstats can_pstats; /* receive list statistics */ |
| 94 | |
| 95 | /* |
| 96 | * af_can socket functions |
| 97 | */ |
| 98 | |
| 99 | int can_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg) |
| 100 | { |
| 101 | struct sock *sk = sock->sk; |
| 102 | |
| 103 | switch (cmd) { |
| 104 | |
| 105 | case SIOCGSTAMP: |
| 106 | return sock_get_timestamp(sk, (struct timeval __user *)arg); |
| 107 | |
| 108 | default: |
| 109 | return -ENOIOCTLCMD; |
| 110 | } |
| 111 | } |
| 112 | EXPORT_SYMBOL(can_ioctl); |
| 113 | |
| 114 | static void can_sock_destruct(struct sock *sk) |
| 115 | { |
| 116 | skb_queue_purge(&sk->sk_receive_queue); |
| 117 | } |
| 118 | |
| 119 | static const struct can_proto *can_get_proto(int protocol) |
| 120 | { |
| 121 | const struct can_proto *cp; |
| 122 | |
| 123 | rcu_read_lock(); |
| 124 | cp = rcu_dereference(proto_tab[protocol]); |
| 125 | if (cp && !try_module_get(cp->prot->owner)) |
| 126 | cp = NULL; |
| 127 | rcu_read_unlock(); |
| 128 | |
| 129 | return cp; |
| 130 | } |
| 131 | |
| 132 | static inline void can_put_proto(const struct can_proto *cp) |
| 133 | { |
| 134 | module_put(cp->prot->owner); |
| 135 | } |
| 136 | |
| 137 | static int can_create(struct net *net, struct socket *sock, int protocol, |
| 138 | int kern) |
| 139 | { |
| 140 | struct sock *sk; |
| 141 | const struct can_proto *cp; |
| 142 | int err = 0; |
| 143 | |
| 144 | sock->state = SS_UNCONNECTED; |
| 145 | |
| 146 | if (protocol < 0 || protocol >= CAN_NPROTO) |
| 147 | return -EINVAL; |
| 148 | |
| 149 | if (!net_eq(net, &init_net)) |
| 150 | return -EAFNOSUPPORT; |
| 151 | |
| 152 | cp = can_get_proto(protocol); |
| 153 | |
| 154 | #ifdef CONFIG_MODULES |
| 155 | if (!cp) { |
| 156 | /* try to load protocol module if kernel is modular */ |
| 157 | |
| 158 | err = request_module("can-proto-%d", protocol); |
| 159 | |
| 160 | /* |
| 161 | * In case of error we only print a message but don't |
| 162 | * return the error code immediately. Below we will |
| 163 | * return -EPROTONOSUPPORT |
| 164 | */ |
| 165 | if (err) |
| 166 | printk_ratelimited(KERN_ERR "can: request_module " |
| 167 | "(can-proto-%d) failed.\n", protocol); |
| 168 | |
| 169 | cp = can_get_proto(protocol); |
| 170 | } |
| 171 | #endif |
| 172 | |
| 173 | /* check for available protocol and correct usage */ |
| 174 | |
| 175 | if (!cp) |
| 176 | return -EPROTONOSUPPORT; |
| 177 | |
| 178 | if (cp->type != sock->type) { |
| 179 | err = -EPROTOTYPE; |
| 180 | goto errout; |
| 181 | } |
| 182 | |
| 183 | sock->ops = cp->ops; |
| 184 | |
| 185 | sk = sk_alloc(net, PF_CAN, GFP_KERNEL, cp->prot); |
| 186 | if (!sk) { |
| 187 | err = -ENOMEM; |
| 188 | goto errout; |
| 189 | } |
| 190 | |
| 191 | sock_init_data(sock, sk); |
| 192 | sk->sk_destruct = can_sock_destruct; |
| 193 | |
| 194 | if (sk->sk_prot->init) |
| 195 | err = sk->sk_prot->init(sk); |
| 196 | |
| 197 | if (err) { |
| 198 | /* release sk on errors */ |
| 199 | sock_orphan(sk); |
| 200 | sock_put(sk); |
| 201 | } |
| 202 | |
| 203 | errout: |
| 204 | can_put_proto(cp); |
| 205 | return err; |
| 206 | } |
| 207 | |
| 208 | /* |
| 209 | * af_can tx path |
| 210 | */ |
| 211 | |
| 212 | /** |
| 213 | * can_send - transmit a CAN frame (optional with local loopback) |
| 214 | * @skb: pointer to socket buffer with CAN frame in data section |
| 215 | * @loop: loopback for listeners on local CAN sockets (recommended default!) |
| 216 | * |
| 217 | * Due to the loopback this routine must not be called from hardirq context. |
| 218 | * |
| 219 | * Return: |
| 220 | * 0 on success |
| 221 | * -ENETDOWN when the selected interface is down |
| 222 | * -ENOBUFS on full driver queue (see net_xmit_errno()) |
| 223 | * -ENOMEM when local loopback failed at calling skb_clone() |
| 224 | * -EPERM when trying to send on a non-CAN interface |
| 225 | * -EMSGSIZE CAN frame size is bigger than CAN interface MTU |
| 226 | * -EINVAL when the skb->data does not contain a valid CAN frame |
| 227 | */ |
| 228 | int can_send(struct sk_buff *skb, int loop) |
| 229 | { |
| 230 | struct sk_buff *newskb = NULL; |
| 231 | struct canfd_frame *cfd = (struct canfd_frame *)skb->data; |
| 232 | int err = -EINVAL; |
| 233 | |
| 234 | if (skb->len == CAN_MTU) { |
| 235 | skb->protocol = htons(ETH_P_CAN); |
| 236 | if (unlikely(cfd->len > CAN_MAX_DLEN)) |
| 237 | goto inval_skb; |
| 238 | } else if (skb->len == CANFD_MTU) { |
| 239 | skb->protocol = htons(ETH_P_CANFD); |
| 240 | if (unlikely(cfd->len > CANFD_MAX_DLEN)) |
| 241 | goto inval_skb; |
| 242 | } else |
| 243 | goto inval_skb; |
| 244 | |
| 245 | /* |
| 246 | * Make sure the CAN frame can pass the selected CAN netdevice. |
| 247 | * As structs can_frame and canfd_frame are similar, we can provide |
| 248 | * CAN FD frames to legacy CAN drivers as long as the length is <= 8 |
| 249 | */ |
| 250 | if (unlikely(skb->len > skb->dev->mtu && cfd->len > CAN_MAX_DLEN)) { |
| 251 | err = -EMSGSIZE; |
| 252 | goto inval_skb; |
| 253 | } |
| 254 | |
| 255 | if (unlikely(skb->dev->type != ARPHRD_CAN)) { |
| 256 | err = -EPERM; |
| 257 | goto inval_skb; |
| 258 | } |
| 259 | |
| 260 | if (unlikely(!(skb->dev->flags & IFF_UP))) { |
| 261 | err = -ENETDOWN; |
| 262 | goto inval_skb; |
| 263 | } |
| 264 | |
| 265 | skb->ip_summed = CHECKSUM_UNNECESSARY; |
| 266 | |
| 267 | skb_reset_mac_header(skb); |
| 268 | skb_reset_network_header(skb); |
| 269 | skb_reset_transport_header(skb); |
| 270 | |
| 271 | if (loop) { |
| 272 | /* local loopback of sent CAN frames */ |
| 273 | |
| 274 | /* indication for the CAN driver: do loopback */ |
| 275 | skb->pkt_type = PACKET_LOOPBACK; |
| 276 | |
| 277 | /* |
| 278 | * The reference to the originating sock may be required |
| 279 | * by the receiving socket to check whether the frame is |
| 280 | * its own. Example: can_raw sockopt CAN_RAW_RECV_OWN_MSGS |
| 281 | * Therefore we have to ensure that skb->sk remains the |
| 282 | * reference to the originating sock by restoring skb->sk |
| 283 | * after each skb_clone() or skb_orphan() usage. |
| 284 | */ |
| 285 | |
| 286 | if (!(skb->dev->flags & IFF_ECHO)) { |
| 287 | /* |
| 288 | * If the interface is not capable to do loopback |
| 289 | * itself, we do it here. |
| 290 | */ |
| 291 | newskb = skb_clone(skb, GFP_ATOMIC); |
| 292 | if (!newskb) { |
| 293 | kfree_skb(skb); |
| 294 | return -ENOMEM; |
| 295 | } |
| 296 | |
| 297 | can_skb_set_owner(newskb, skb->sk); |
| 298 | newskb->ip_summed = CHECKSUM_UNNECESSARY; |
| 299 | newskb->pkt_type = PACKET_BROADCAST; |
| 300 | } |
| 301 | } else { |
| 302 | /* indication for the CAN driver: no loopback required */ |
| 303 | skb->pkt_type = PACKET_HOST; |
| 304 | } |
| 305 | |
| 306 | /* send to netdevice */ |
| 307 | err = dev_queue_xmit(skb); |
| 308 | if (err > 0) |
| 309 | err = net_xmit_errno(err); |
| 310 | |
| 311 | if (err) { |
| 312 | kfree_skb(newskb); |
| 313 | return err; |
| 314 | } |
| 315 | |
| 316 | if (newskb) |
| 317 | netif_rx_ni(newskb); |
| 318 | |
| 319 | /* update statistics */ |
| 320 | can_stats.tx_frames++; |
| 321 | can_stats.tx_frames_delta++; |
| 322 | |
| 323 | return 0; |
| 324 | |
| 325 | inval_skb: |
| 326 | kfree_skb(skb); |
| 327 | return err; |
| 328 | } |
| 329 | EXPORT_SYMBOL(can_send); |
| 330 | |
| 331 | /* |
| 332 | * af_can rx path |
| 333 | */ |
| 334 | |
| 335 | static struct dev_rcv_lists *find_dev_rcv_lists(struct net_device *dev) |
| 336 | { |
| 337 | if (!dev) |
| 338 | return &can_rx_alldev_list; |
| 339 | else |
| 340 | return (struct dev_rcv_lists *)dev->ml_priv; |
| 341 | } |
| 342 | |
| 343 | /** |
| 344 | * find_rcv_list - determine optimal filterlist inside device filter struct |
| 345 | * @can_id: pointer to CAN identifier of a given can_filter |
| 346 | * @mask: pointer to CAN mask of a given can_filter |
| 347 | * @d: pointer to the device filter struct |
| 348 | * |
| 349 | * Description: |
| 350 | * Returns the optimal filterlist to reduce the filter handling in the |
| 351 | * receive path. This function is called by service functions that need |
| 352 | * to register or unregister a can_filter in the filter lists. |
| 353 | * |
| 354 | * A filter matches in general, when |
| 355 | * |
| 356 | * <received_can_id> & mask == can_id & mask |
| 357 | * |
| 358 | * so every bit set in the mask (even CAN_EFF_FLAG, CAN_RTR_FLAG) describe |
| 359 | * relevant bits for the filter. |
| 360 | * |
| 361 | * The filter can be inverted (CAN_INV_FILTER bit set in can_id) or it can |
| 362 | * filter for error messages (CAN_ERR_FLAG bit set in mask). For error msg |
| 363 | * frames there is a special filterlist and a special rx path filter handling. |
| 364 | * |
| 365 | * Return: |
| 366 | * Pointer to optimal filterlist for the given can_id/mask pair. |
| 367 | * Constistency checked mask. |
| 368 | * Reduced can_id to have a preprocessed filter compare value. |
| 369 | */ |
| 370 | static struct hlist_head *find_rcv_list(canid_t *can_id, canid_t *mask, |
| 371 | struct dev_rcv_lists *d) |
| 372 | { |
| 373 | canid_t inv = *can_id & CAN_INV_FILTER; /* save flag before masking */ |
| 374 | |
| 375 | /* filter for error message frames in extra filterlist */ |
| 376 | if (*mask & CAN_ERR_FLAG) { |
| 377 | /* clear CAN_ERR_FLAG in filter entry */ |
| 378 | *mask &= CAN_ERR_MASK; |
| 379 | return &d->rx[RX_ERR]; |
| 380 | } |
| 381 | |
| 382 | /* with cleared CAN_ERR_FLAG we have a simple mask/value filterpair */ |
| 383 | |
| 384 | #define CAN_EFF_RTR_FLAGS (CAN_EFF_FLAG | CAN_RTR_FLAG) |
| 385 | |
| 386 | /* ensure valid values in can_mask for 'SFF only' frame filtering */ |
| 387 | if ((*mask & CAN_EFF_FLAG) && !(*can_id & CAN_EFF_FLAG)) |
| 388 | *mask &= (CAN_SFF_MASK | CAN_EFF_RTR_FLAGS); |
| 389 | |
| 390 | /* reduce condition testing at receive time */ |
| 391 | *can_id &= *mask; |
| 392 | |
| 393 | /* inverse can_id/can_mask filter */ |
| 394 | if (inv) |
| 395 | return &d->rx[RX_INV]; |
| 396 | |
| 397 | /* mask == 0 => no condition testing at receive time */ |
| 398 | if (!(*mask)) |
| 399 | return &d->rx[RX_ALL]; |
| 400 | |
| 401 | /* extra filterlists for the subscription of a single non-RTR can_id */ |
| 402 | if (((*mask & CAN_EFF_RTR_FLAGS) == CAN_EFF_RTR_FLAGS) && |
| 403 | !(*can_id & CAN_RTR_FLAG)) { |
| 404 | |
| 405 | if (*can_id & CAN_EFF_FLAG) { |
| 406 | if (*mask == (CAN_EFF_MASK | CAN_EFF_RTR_FLAGS)) { |
| 407 | /* RFC: a future use-case for hash-tables? */ |
| 408 | return &d->rx[RX_EFF]; |
| 409 | } |
| 410 | } else { |
| 411 | if (*mask == (CAN_SFF_MASK | CAN_EFF_RTR_FLAGS)) |
| 412 | return &d->rx_sff[*can_id]; |
| 413 | } |
| 414 | } |
| 415 | |
| 416 | /* default: filter via can_id/can_mask */ |
| 417 | return &d->rx[RX_FIL]; |
| 418 | } |
| 419 | |
| 420 | /** |
| 421 | * can_rx_register - subscribe CAN frames from a specific interface |
| 422 | * @dev: pointer to netdevice (NULL => subcribe from 'all' CAN devices list) |
| 423 | * @can_id: CAN identifier (see description) |
| 424 | * @mask: CAN mask (see description) |
| 425 | * @func: callback function on filter match |
| 426 | * @data: returned parameter for callback function |
| 427 | * @ident: string for calling module indentification |
| 428 | * @sk: socket pointer (might be NULL) |
| 429 | * |
| 430 | * Description: |
| 431 | * Invokes the callback function with the received sk_buff and the given |
| 432 | * parameter 'data' on a matching receive filter. A filter matches, when |
| 433 | * |
| 434 | * <received_can_id> & mask == can_id & mask |
| 435 | * |
| 436 | * The filter can be inverted (CAN_INV_FILTER bit set in can_id) or it can |
| 437 | * filter for error message frames (CAN_ERR_FLAG bit set in mask). |
| 438 | * |
| 439 | * The provided pointer to the sk_buff is guaranteed to be valid as long as |
| 440 | * the callback function is running. The callback function must *not* free |
| 441 | * the given sk_buff while processing it's task. When the given sk_buff is |
| 442 | * needed after the end of the callback function it must be cloned inside |
| 443 | * the callback function with skb_clone(). |
| 444 | * |
| 445 | * Return: |
| 446 | * 0 on success |
| 447 | * -ENOMEM on missing cache mem to create subscription entry |
| 448 | * -ENODEV unknown device |
| 449 | */ |
| 450 | int can_rx_register(struct net_device *dev, canid_t can_id, canid_t mask, |
| 451 | void (*func)(struct sk_buff *, void *), void *data, |
| 452 | char *ident, struct sock *sk) |
| 453 | { |
| 454 | struct receiver *r; |
| 455 | struct hlist_head *rl; |
| 456 | struct dev_rcv_lists *d; |
| 457 | int err = 0; |
| 458 | |
| 459 | /* insert new receiver (dev,canid,mask) -> (func,data) */ |
| 460 | |
| 461 | if (dev && dev->type != ARPHRD_CAN) |
| 462 | return -ENODEV; |
| 463 | |
| 464 | r = kmem_cache_alloc(rcv_cache, GFP_KERNEL); |
| 465 | if (!r) |
| 466 | return -ENOMEM; |
| 467 | |
| 468 | spin_lock(&can_rcvlists_lock); |
| 469 | |
| 470 | d = find_dev_rcv_lists(dev); |
| 471 | if (d) { |
| 472 | rl = find_rcv_list(&can_id, &mask, d); |
| 473 | |
| 474 | r->can_id = can_id; |
| 475 | r->mask = mask; |
| 476 | r->matches = 0; |
| 477 | r->func = func; |
| 478 | r->data = data; |
| 479 | r->ident = ident; |
| 480 | r->sk = sk; |
| 481 | |
| 482 | hlist_add_head_rcu(&r->list, rl); |
| 483 | d->entries++; |
| 484 | |
| 485 | can_pstats.rcv_entries++; |
| 486 | if (can_pstats.rcv_entries_max < can_pstats.rcv_entries) |
| 487 | can_pstats.rcv_entries_max = can_pstats.rcv_entries; |
| 488 | } else { |
| 489 | kmem_cache_free(rcv_cache, r); |
| 490 | err = -ENODEV; |
| 491 | } |
| 492 | |
| 493 | spin_unlock(&can_rcvlists_lock); |
| 494 | |
| 495 | return err; |
| 496 | } |
| 497 | EXPORT_SYMBOL(can_rx_register); |
| 498 | |
| 499 | /* |
| 500 | * can_rx_delete_receiver - rcu callback for single receiver entry removal |
| 501 | */ |
| 502 | static void can_rx_delete_receiver(struct rcu_head *rp) |
| 503 | { |
| 504 | struct receiver *r = container_of(rp, struct receiver, rcu); |
| 505 | struct sock *sk = r->sk; |
| 506 | |
| 507 | kmem_cache_free(rcv_cache, r); |
| 508 | if (sk) |
| 509 | sock_put(sk); |
| 510 | } |
| 511 | |
| 512 | /** |
| 513 | * can_rx_unregister - unsubscribe CAN frames from a specific interface |
| 514 | * @dev: pointer to netdevice (NULL => unsubcribe from 'all' CAN devices list) |
| 515 | * @can_id: CAN identifier |
| 516 | * @mask: CAN mask |
| 517 | * @func: callback function on filter match |
| 518 | * @data: returned parameter for callback function |
| 519 | * |
| 520 | * Description: |
| 521 | * Removes subscription entry depending on given (subscription) values. |
| 522 | */ |
| 523 | void can_rx_unregister(struct net_device *dev, canid_t can_id, canid_t mask, |
| 524 | void (*func)(struct sk_buff *, void *), void *data) |
| 525 | { |
| 526 | struct receiver *r = NULL; |
| 527 | struct hlist_head *rl; |
| 528 | struct dev_rcv_lists *d; |
| 529 | |
| 530 | if (dev && dev->type != ARPHRD_CAN) |
| 531 | return; |
| 532 | |
| 533 | spin_lock(&can_rcvlists_lock); |
| 534 | |
| 535 | d = find_dev_rcv_lists(dev); |
| 536 | if (!d) { |
| 537 | pr_err("BUG: receive list not found for " |
| 538 | "dev %s, id %03X, mask %03X\n", |
| 539 | DNAME(dev), can_id, mask); |
| 540 | goto out; |
| 541 | } |
| 542 | |
| 543 | rl = find_rcv_list(&can_id, &mask, d); |
| 544 | |
| 545 | /* |
| 546 | * Search the receiver list for the item to delete. This should |
| 547 | * exist, since no receiver may be unregistered that hasn't |
| 548 | * been registered before. |
| 549 | */ |
| 550 | |
| 551 | hlist_for_each_entry_rcu(r, rl, list) { |
| 552 | if (r->can_id == can_id && r->mask == mask && |
| 553 | r->func == func && r->data == data) |
| 554 | break; |
| 555 | } |
| 556 | |
| 557 | /* |
| 558 | * Check for bugs in CAN protocol implementations using af_can.c: |
| 559 | * 'r' will be NULL if no matching list item was found for removal. |
| 560 | */ |
| 561 | |
| 562 | if (!r) { |
| 563 | WARN(1, "BUG: receive list entry not found for dev %s, " |
| 564 | "id %03X, mask %03X\n", DNAME(dev), can_id, mask); |
| 565 | goto out; |
| 566 | } |
| 567 | |
| 568 | hlist_del_rcu(&r->list); |
| 569 | d->entries--; |
| 570 | |
| 571 | if (can_pstats.rcv_entries > 0) |
| 572 | can_pstats.rcv_entries--; |
| 573 | |
| 574 | /* remove device structure requested by NETDEV_UNREGISTER */ |
| 575 | if (d->remove_on_zero_entries && !d->entries) { |
| 576 | kfree(d); |
| 577 | dev->ml_priv = NULL; |
| 578 | } |
| 579 | |
| 580 | out: |
| 581 | spin_unlock(&can_rcvlists_lock); |
| 582 | |
| 583 | /* schedule the receiver item for deletion */ |
| 584 | if (r) { |
| 585 | if (r->sk) |
| 586 | sock_hold(r->sk); |
| 587 | call_rcu(&r->rcu, can_rx_delete_receiver); |
| 588 | } |
| 589 | } |
| 590 | EXPORT_SYMBOL(can_rx_unregister); |
| 591 | |
| 592 | static inline void deliver(struct sk_buff *skb, struct receiver *r) |
| 593 | { |
| 594 | r->func(skb, r->data); |
| 595 | r->matches++; |
| 596 | } |
| 597 | |
| 598 | static int can_rcv_filter(struct dev_rcv_lists *d, struct sk_buff *skb) |
| 599 | { |
| 600 | struct receiver *r; |
| 601 | int matches = 0; |
| 602 | struct can_frame *cf = (struct can_frame *)skb->data; |
| 603 | canid_t can_id = cf->can_id; |
| 604 | |
| 605 | if (d->entries == 0) |
| 606 | return 0; |
| 607 | |
| 608 | if (can_id & CAN_ERR_FLAG) { |
| 609 | /* check for error message frame entries only */ |
| 610 | hlist_for_each_entry_rcu(r, &d->rx[RX_ERR], list) { |
| 611 | if (can_id & r->mask) { |
| 612 | deliver(skb, r); |
| 613 | matches++; |
| 614 | } |
| 615 | } |
| 616 | return matches; |
| 617 | } |
| 618 | |
| 619 | /* check for unfiltered entries */ |
| 620 | hlist_for_each_entry_rcu(r, &d->rx[RX_ALL], list) { |
| 621 | deliver(skb, r); |
| 622 | matches++; |
| 623 | } |
| 624 | |
| 625 | /* check for can_id/mask entries */ |
| 626 | hlist_for_each_entry_rcu(r, &d->rx[RX_FIL], list) { |
| 627 | if ((can_id & r->mask) == r->can_id) { |
| 628 | deliver(skb, r); |
| 629 | matches++; |
| 630 | } |
| 631 | } |
| 632 | |
| 633 | /* check for inverted can_id/mask entries */ |
| 634 | hlist_for_each_entry_rcu(r, &d->rx[RX_INV], list) { |
| 635 | if ((can_id & r->mask) != r->can_id) { |
| 636 | deliver(skb, r); |
| 637 | matches++; |
| 638 | } |
| 639 | } |
| 640 | |
| 641 | /* check filterlists for single non-RTR can_ids */ |
| 642 | if (can_id & CAN_RTR_FLAG) |
| 643 | return matches; |
| 644 | |
| 645 | if (can_id & CAN_EFF_FLAG) { |
| 646 | hlist_for_each_entry_rcu(r, &d->rx[RX_EFF], list) { |
| 647 | if (r->can_id == can_id) { |
| 648 | deliver(skb, r); |
| 649 | matches++; |
| 650 | } |
| 651 | } |
| 652 | } else { |
| 653 | can_id &= CAN_SFF_MASK; |
| 654 | hlist_for_each_entry_rcu(r, &d->rx_sff[can_id], list) { |
| 655 | deliver(skb, r); |
| 656 | matches++; |
| 657 | } |
| 658 | } |
| 659 | |
| 660 | return matches; |
| 661 | } |
| 662 | |
| 663 | static void can_receive(struct sk_buff *skb, struct net_device *dev) |
| 664 | { |
| 665 | struct dev_rcv_lists *d; |
| 666 | int matches; |
| 667 | |
| 668 | /* update statistics */ |
| 669 | can_stats.rx_frames++; |
| 670 | can_stats.rx_frames_delta++; |
| 671 | |
| 672 | rcu_read_lock(); |
| 673 | |
| 674 | /* deliver the packet to sockets listening on all devices */ |
| 675 | matches = can_rcv_filter(&can_rx_alldev_list, skb); |
| 676 | |
| 677 | /* find receive list for this device */ |
| 678 | d = find_dev_rcv_lists(dev); |
| 679 | if (d) |
| 680 | matches += can_rcv_filter(d, skb); |
| 681 | |
| 682 | rcu_read_unlock(); |
| 683 | |
| 684 | /* consume the skbuff allocated by the netdevice driver */ |
| 685 | consume_skb(skb); |
| 686 | |
| 687 | if (matches > 0) { |
| 688 | can_stats.matches++; |
| 689 | can_stats.matches_delta++; |
| 690 | } |
| 691 | } |
| 692 | |
| 693 | static int can_rcv(struct sk_buff *skb, struct net_device *dev, |
| 694 | struct packet_type *pt, struct net_device *orig_dev) |
| 695 | { |
| 696 | struct canfd_frame *cfd = (struct canfd_frame *)skb->data; |
| 697 | |
| 698 | if (unlikely(!net_eq(dev_net(dev), &init_net))) |
| 699 | goto drop; |
| 700 | |
| 701 | if (WARN_ONCE(dev->type != ARPHRD_CAN || |
| 702 | skb->len != CAN_MTU || |
| 703 | cfd->len > CAN_MAX_DLEN, |
| 704 | "PF_CAN: dropped non conform CAN skbuf: " |
| 705 | "dev type %d, len %d, datalen %d\n", |
| 706 | dev->type, skb->len, cfd->len)) |
| 707 | goto drop; |
| 708 | |
| 709 | can_receive(skb, dev); |
| 710 | return NET_RX_SUCCESS; |
| 711 | |
| 712 | drop: |
| 713 | kfree_skb(skb); |
| 714 | return NET_RX_DROP; |
| 715 | } |
| 716 | |
| 717 | static int canfd_rcv(struct sk_buff *skb, struct net_device *dev, |
| 718 | struct packet_type *pt, struct net_device *orig_dev) |
| 719 | { |
| 720 | struct canfd_frame *cfd = (struct canfd_frame *)skb->data; |
| 721 | |
| 722 | if (unlikely(!net_eq(dev_net(dev), &init_net))) |
| 723 | goto drop; |
| 724 | |
| 725 | if (WARN_ONCE(dev->type != ARPHRD_CAN || |
| 726 | skb->len != CANFD_MTU || |
| 727 | cfd->len > CANFD_MAX_DLEN, |
| 728 | "PF_CAN: dropped non conform CAN FD skbuf: " |
| 729 | "dev type %d, len %d, datalen %d\n", |
| 730 | dev->type, skb->len, cfd->len)) |
| 731 | goto drop; |
| 732 | |
| 733 | can_receive(skb, dev); |
| 734 | return NET_RX_SUCCESS; |
| 735 | |
| 736 | drop: |
| 737 | kfree_skb(skb); |
| 738 | return NET_RX_DROP; |
| 739 | } |
| 740 | |
| 741 | /* |
| 742 | * af_can protocol functions |
| 743 | */ |
| 744 | |
| 745 | /** |
| 746 | * can_proto_register - register CAN transport protocol |
| 747 | * @cp: pointer to CAN protocol structure |
| 748 | * |
| 749 | * Return: |
| 750 | * 0 on success |
| 751 | * -EINVAL invalid (out of range) protocol number |
| 752 | * -EBUSY protocol already in use |
| 753 | * -ENOBUF if proto_register() fails |
| 754 | */ |
| 755 | int can_proto_register(const struct can_proto *cp) |
| 756 | { |
| 757 | int proto = cp->protocol; |
| 758 | int err = 0; |
| 759 | |
| 760 | if (proto < 0 || proto >= CAN_NPROTO) { |
| 761 | pr_err("can: protocol number %d out of range\n", proto); |
| 762 | return -EINVAL; |
| 763 | } |
| 764 | |
| 765 | err = proto_register(cp->prot, 0); |
| 766 | if (err < 0) |
| 767 | return err; |
| 768 | |
| 769 | mutex_lock(&proto_tab_lock); |
| 770 | |
| 771 | if (proto_tab[proto]) { |
| 772 | pr_err("can: protocol %d already registered\n", proto); |
| 773 | err = -EBUSY; |
| 774 | } else |
| 775 | RCU_INIT_POINTER(proto_tab[proto], cp); |
| 776 | |
| 777 | mutex_unlock(&proto_tab_lock); |
| 778 | |
| 779 | if (err < 0) |
| 780 | proto_unregister(cp->prot); |
| 781 | |
| 782 | return err; |
| 783 | } |
| 784 | EXPORT_SYMBOL(can_proto_register); |
| 785 | |
| 786 | /** |
| 787 | * can_proto_unregister - unregister CAN transport protocol |
| 788 | * @cp: pointer to CAN protocol structure |
| 789 | */ |
| 790 | void can_proto_unregister(const struct can_proto *cp) |
| 791 | { |
| 792 | int proto = cp->protocol; |
| 793 | |
| 794 | mutex_lock(&proto_tab_lock); |
| 795 | BUG_ON(proto_tab[proto] != cp); |
| 796 | RCU_INIT_POINTER(proto_tab[proto], NULL); |
| 797 | mutex_unlock(&proto_tab_lock); |
| 798 | |
| 799 | synchronize_rcu(); |
| 800 | |
| 801 | proto_unregister(cp->prot); |
| 802 | } |
| 803 | EXPORT_SYMBOL(can_proto_unregister); |
| 804 | |
| 805 | /* |
| 806 | * af_can notifier to create/remove CAN netdevice specific structs |
| 807 | */ |
| 808 | static int can_notifier(struct notifier_block *nb, unsigned long msg, |
| 809 | void *data) |
| 810 | { |
| 811 | struct net_device *dev = (struct net_device *)data; |
| 812 | struct dev_rcv_lists *d; |
| 813 | |
| 814 | if (!net_eq(dev_net(dev), &init_net)) |
| 815 | return NOTIFY_DONE; |
| 816 | |
| 817 | if (dev->type != ARPHRD_CAN) |
| 818 | return NOTIFY_DONE; |
| 819 | |
| 820 | switch (msg) { |
| 821 | |
| 822 | case NETDEV_REGISTER: |
| 823 | |
| 824 | /* create new dev_rcv_lists for this device */ |
| 825 | d = kzalloc(sizeof(*d), GFP_KERNEL); |
| 826 | if (!d) |
| 827 | return NOTIFY_DONE; |
| 828 | BUG_ON(dev->ml_priv); |
| 829 | dev->ml_priv = d; |
| 830 | |
| 831 | break; |
| 832 | |
| 833 | case NETDEV_UNREGISTER: |
| 834 | spin_lock(&can_rcvlists_lock); |
| 835 | |
| 836 | d = dev->ml_priv; |
| 837 | if (d) { |
| 838 | if (d->entries) |
| 839 | d->remove_on_zero_entries = 1; |
| 840 | else { |
| 841 | kfree(d); |
| 842 | dev->ml_priv = NULL; |
| 843 | } |
| 844 | } else |
| 845 | pr_err("can: notifier: receive list not found for dev " |
| 846 | "%s\n", dev->name); |
| 847 | |
| 848 | spin_unlock(&can_rcvlists_lock); |
| 849 | |
| 850 | break; |
| 851 | } |
| 852 | |
| 853 | return NOTIFY_DONE; |
| 854 | } |
| 855 | |
| 856 | /* |
| 857 | * af_can module init/exit functions |
| 858 | */ |
| 859 | |
| 860 | static struct packet_type can_packet __read_mostly = { |
| 861 | .type = cpu_to_be16(ETH_P_CAN), |
| 862 | .func = can_rcv, |
| 863 | }; |
| 864 | |
| 865 | static struct packet_type canfd_packet __read_mostly = { |
| 866 | .type = cpu_to_be16(ETH_P_CANFD), |
| 867 | .func = canfd_rcv, |
| 868 | }; |
| 869 | |
| 870 | static const struct net_proto_family can_family_ops = { |
| 871 | .family = PF_CAN, |
| 872 | .create = can_create, |
| 873 | .owner = THIS_MODULE, |
| 874 | }; |
| 875 | |
| 876 | /* notifier block for netdevice event */ |
| 877 | static struct notifier_block can_netdev_notifier __read_mostly = { |
| 878 | .notifier_call = can_notifier, |
| 879 | }; |
| 880 | |
| 881 | static __init int can_init(void) |
| 882 | { |
| 883 | /* check for correct padding to be able to use the structs similarly */ |
| 884 | BUILD_BUG_ON(offsetof(struct can_frame, can_dlc) != |
| 885 | offsetof(struct canfd_frame, len) || |
| 886 | offsetof(struct can_frame, data) != |
| 887 | offsetof(struct canfd_frame, data)); |
| 888 | |
| 889 | printk(banner); |
| 890 | |
| 891 | memset(&can_rx_alldev_list, 0, sizeof(can_rx_alldev_list)); |
| 892 | |
| 893 | rcv_cache = kmem_cache_create("can_receiver", sizeof(struct receiver), |
| 894 | 0, 0, NULL); |
| 895 | if (!rcv_cache) |
| 896 | return -ENOMEM; |
| 897 | |
| 898 | if (stats_timer) { |
| 899 | /* the statistics are updated every second (timer triggered) */ |
| 900 | setup_timer(&can_stattimer, can_stat_update, 0); |
| 901 | mod_timer(&can_stattimer, round_jiffies(jiffies + HZ)); |
| 902 | } else |
| 903 | can_stattimer.function = NULL; |
| 904 | |
| 905 | can_init_proc(); |
| 906 | |
| 907 | /* protocol register */ |
| 908 | sock_register(&can_family_ops); |
| 909 | register_netdevice_notifier(&can_netdev_notifier); |
| 910 | dev_add_pack(&can_packet); |
| 911 | dev_add_pack(&canfd_packet); |
| 912 | |
| 913 | return 0; |
| 914 | } |
| 915 | |
| 916 | static __exit void can_exit(void) |
| 917 | { |
| 918 | struct net_device *dev; |
| 919 | |
| 920 | if (stats_timer) |
| 921 | del_timer_sync(&can_stattimer); |
| 922 | |
| 923 | can_remove_proc(); |
| 924 | |
| 925 | /* protocol unregister */ |
| 926 | dev_remove_pack(&canfd_packet); |
| 927 | dev_remove_pack(&can_packet); |
| 928 | unregister_netdevice_notifier(&can_netdev_notifier); |
| 929 | sock_unregister(PF_CAN); |
| 930 | |
| 931 | /* remove created dev_rcv_lists from still registered CAN devices */ |
| 932 | rcu_read_lock(); |
| 933 | for_each_netdev_rcu(&init_net, dev) { |
| 934 | if (dev->type == ARPHRD_CAN && dev->ml_priv) { |
| 935 | |
| 936 | struct dev_rcv_lists *d = dev->ml_priv; |
| 937 | |
| 938 | BUG_ON(d->entries); |
| 939 | kfree(d); |
| 940 | dev->ml_priv = NULL; |
| 941 | } |
| 942 | } |
| 943 | rcu_read_unlock(); |
| 944 | |
| 945 | rcu_barrier(); /* Wait for completion of call_rcu()'s */ |
| 946 | |
| 947 | kmem_cache_destroy(rcv_cache); |
| 948 | } |
| 949 | |
| 950 | module_init(can_init); |
| 951 | module_exit(can_exit); |