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