net/bridge/br_fdb.c

   1 /*
   2  *      Forwarding database
   3  *      Linux ethernet bridge
   4  *
   5  *      Authors:
   6  *      Lennert Buytenhek               <buytenh@gnu.org>
   7  *
   8  *      This program is free software; you can redistribute it and/or
   9  *      modify it under the terms of the GNU General Public License
  10  *      as published by the Free Software Foundation; either version
  11  *      2 of the License, or (at your option) any later version.
  12  */
  13
  14 #include <linux/kernel.h>
  15 #include <linux/init.h>
  16 #include <linux/rculist.h>
  17 #include <linux/spinlock.h>
  18 #include <linux/times.h>
  19 #include <linux/netdevice.h>
  20 #include <linux/etherdevice.h>
  21 #include <linux/jhash.h>
  22 #include <linux/random.h>
  23 #include <linux/slab.h>
  24 #include <linux/atomic.h>
  25 #include <asm/unaligned.h>
  26 #include "br_private.h"
  27
  28 static struct kmem_cache *br_fdb_cache __read_mostly;
  29 static int fdb_insert(struct net_bridge *br, struct net_bridge_port *source,
  30                       const unsigned char *addr);
  31 static void fdb_notify(const struct net_bridge_fdb_entry *, int);
  32
  33 static u32 fdb_salt __read_mostly;
  34
  35 int __init br_fdb_init(void)
  36 {
  37         br_fdb_cache = kmem_cache_create("bridge_fdb_cache",
  38                                          sizeof(struct net_bridge_fdb_entry),
  39                                          0,
  40                                          SLAB_HWCACHE_ALIGN, NULL);
  41         if (!br_fdb_cache)
  42                 return -ENOMEM;
  43
  44         get_random_bytes(&fdb_salt, sizeof(fdb_salt));
  45         return 0;
  46 }
  47
  48 void br_fdb_fini(void)
  49 {
  50         kmem_cache_destroy(br_fdb_cache);
  51 }
  52
  53
  54 /* if topology_changing then use forward_delay (default 15 sec)
  55  * otherwise keep longer (default 5 minutes)
  56  */
  57 static inline unsigned long hold_time(const struct net_bridge *br)
  58 {
  59         return br->topology_change ? br->forward_delay : br->ageing_time;
  60 }
  61
  62 static inline int has_expired(const struct net_bridge *br,
  63                                   const struct net_bridge_fdb_entry *fdb)
  64 {
  65         return !fdb->is_static &&
  66                 time_before_eq(fdb->updated + hold_time(br), jiffies);
  67 }
  68
  69 static inline int br_mac_hash(const unsigned char *mac)
  70 {
  71         /* use 1 byte of OUI cnd 3 bytes of NIC */
  72         u32 key = get_unaligned((u32 *)(mac + 2));
  73         return jhash_1word(key, fdb_salt) & (BR_HASH_SIZE - 1);
  74 }
  75
  76 static void fdb_rcu_free(struct rcu_head *head)
  77 {
  78         struct net_bridge_fdb_entry *ent
  79                 = container_of(head, struct net_bridge_fdb_entry, rcu);
  80         kmem_cache_free(br_fdb_cache, ent);
  81 }
  82
  83 static inline void fdb_delete(struct net_bridge_fdb_entry *f)
  84 {
  85         fdb_notify(f, RTM_DELNEIGH);
  86         hlist_del_rcu(&f->hlist);
  87         call_rcu(&f->rcu, fdb_rcu_free);
  88 }
  89
  90 void br_fdb_changeaddr(struct net_bridge_port *p, const unsigned char *newaddr)
  91 {
  92         struct net_bridge *br = p->br;
  93         int i;
  94
  95         spin_lock_bh(&br->hash_lock);
  96
  97         /* Search all chains since old address/hash is unknown */
  98         for (i = 0; i < BR_HASH_SIZE; i++) {
  99                 struct hlist_node *h;
 100                 hlist_for_each(h, &br->hash[i]) {
 101                         struct net_bridge_fdb_entry *f;
 102
 103                         f = hlist_entry(h, struct net_bridge_fdb_entry, hlist);
 104                         if (f->dst == p && f->is_local) {
 105                                 /* maybe another port has same hw addr? */
 106                                 struct net_bridge_port *op;
 107                                 list_for_each_entry(op, &br->port_list, list) {
 108                                         if (op != p &&
 109                                             !compare_ether_addr(op->dev->dev_addr,
 110                                                                 f->addr.addr)) {
 111                                                 f->dst = op;
 112                                                 goto insert;
 113                                         }
 114                                 }
 115
 116                                 /* delete old one */
 117                                 fdb_delete(f);
 118                                 goto insert;
 119                         }
 120                 }
 121         }
 122  insert:
 123         /* insert new address,  may fail if invalid address or dup. */
 124         fdb_insert(br, p, newaddr);
 125
 126         spin_unlock_bh(&br->hash_lock);
 127 }
 128
 129 void br_fdb_cleanup(unsigned long _data)
 130 {
 131         struct net_bridge *br = (struct net_bridge *)_data;
 132         unsigned long delay = hold_time(br);
 133         unsigned long next_timer = jiffies + br->ageing_time;
 134         int i;
 135
 136         spin_lock_bh(&br->hash_lock);
 137         for (i = 0; i < BR_HASH_SIZE; i++) {
 138                 struct net_bridge_fdb_entry *f;
 139                 struct hlist_node *h, *n;
 140
 141                 hlist_for_each_entry_safe(f, h, n, &br->hash[i], hlist) {
 142                         unsigned long this_timer;
 143                         if (f->is_static)
 144                                 continue;
 145                         this_timer = f->updated + delay;
 146                         if (time_before_eq(this_timer, jiffies))
 147                                 fdb_delete(f);
 148                         else if (time_before(this_timer, next_timer))
 149                                 next_timer = this_timer;
 150                 }
 151         }
 152         spin_unlock_bh(&br->hash_lock);
 153
 154         mod_timer(&br->gc_timer, round_jiffies_up(next_timer));
 155 }
 156
 157 /* Completely flush all dynamic entries in forwarding database.*/
 158 void br_fdb_flush(struct net_bridge *br)
 159 {
 160         int i;
 161
 162         spin_lock_bh(&br->hash_lock);
 163         for (i = 0; i < BR_HASH_SIZE; i++) {
 164                 struct net_bridge_fdb_entry *f;
 165                 struct hlist_node *h, *n;
 166                 hlist_for_each_entry_safe(f, h, n, &br->hash[i], hlist) {
 167                         if (!f->is_static)
 168                                 fdb_delete(f);
 169                 }
 170         }
 171         spin_unlock_bh(&br->hash_lock);
 172 }
 173
 174 /* Flush all entries referring to a specific port.
 175  * if do_all is set also flush static entries
 176  */
 177 void br_fdb_delete_by_port(struct net_bridge *br,
 178                            const struct net_bridge_port *p,
 179                            int do_all)
 180 {
 181         int i;
 182
 183         spin_lock_bh(&br->hash_lock);
 184         for (i = 0; i < BR_HASH_SIZE; i++) {
 185                 struct hlist_node *h, *g;
 186
 187                 hlist_for_each_safe(h, g, &br->hash[i]) {
 188                         struct net_bridge_fdb_entry *f
 189                                 = hlist_entry(h, struct net_bridge_fdb_entry, hlist);
 190                         if (f->dst != p)
 191                                 continue;
 192
 193                         if (f->is_static && !do_all)
 194                                 continue;
 195                         /*
 196                          * if multiple ports all have the same device address
 197                          * then when one port is deleted, assign
 198                          * the local entry to other port
 199                          */
 200                         if (f->is_local) {
 201                                 struct net_bridge_port *op;
 202                                 list_for_each_entry(op, &br->port_list, list) {
 203                                         if (op != p &&
 204                                             !compare_ether_addr(op->dev->dev_addr,
 205                                                                 f->addr.addr)) {
 206                                                 f->dst = op;
 207                                                 goto skip_delete;
 208                                         }
 209                                 }
 210                         }
 211
 212                         fdb_delete(f);
 213                 skip_delete: ;
 214                 }
 215         }
 216         spin_unlock_bh(&br->hash_lock);
 217 }
 218
 219 /* No locking or refcounting, assumes caller has rcu_read_lock */
 220 struct net_bridge_fdb_entry *__br_fdb_get(struct net_bridge *br,
 221                                           const unsigned char *addr)
 222 {
 223         struct hlist_node *h;
 224         struct net_bridge_fdb_entry *fdb;
 225
 226         hlist_for_each_entry_rcu(fdb, h, &br->hash[br_mac_hash(addr)], hlist) {
 227                 if (!compare_ether_addr(fdb->addr.addr, addr)) {
 228                         if (unlikely(has_expired(br, fdb)))
 229                                 break;
 230                         return fdb;
 231                 }
 232         }
 233
 234         return NULL;
 235 }
 236
 237 #if defined(CONFIG_ATM_LANE) || defined(CONFIG_ATM_LANE_MODULE)
 238 /* Interface used by ATM LANE hook to test
 239  * if an addr is on some other bridge port */
 240 int br_fdb_test_addr(struct net_device *dev, unsigned char *addr)
 241 {
 242         struct net_bridge_fdb_entry *fdb;
 243         struct net_bridge_port *port;
 244         int ret;
 245
 246         rcu_read_lock();
 247         port = br_port_get_rcu(dev);
 248         if (!port)
 249                 ret = 0;
 250         else {
 251                 fdb = __br_fdb_get(port->br, addr);
 252                 ret = fdb && fdb->dst->dev != dev &&
 253                         fdb->dst->state == BR_STATE_FORWARDING;
 254         }
 255         rcu_read_unlock();
 256
 257         return ret;
 258 }
 259 #endif /* CONFIG_ATM_LANE */
 260
 261 /*
 262  * Fill buffer with forwarding table records in
 263  * the API format.
 264  */
 265 int br_fdb_fillbuf(struct net_bridge *br, void *buf,
 266                    unsigned long maxnum, unsigned long skip)
 267 {
 268         struct __fdb_entry *fe = buf;
 269         int i, num = 0;
 270         struct hlist_node *h;
 271         struct net_bridge_fdb_entry *f;
 272
 273         memset(buf, 0, maxnum*sizeof(struct __fdb_entry));
 274
 275         rcu_read_lock();
 276         for (i = 0; i < BR_HASH_SIZE; i++) {
 277                 hlist_for_each_entry_rcu(f, h, &br->hash[i], hlist) {
 278                         if (num >= maxnum)
 279                                 goto out;
 280
 281                         if (has_expired(br, f))
 282                                 continue;
 283
 284                         if (skip) {
 285                                 --skip;
 286                                 continue;
 287                         }
 288
 289                         /* convert from internal format to API */
 290                         memcpy(fe->mac_addr, f->addr.addr, ETH_ALEN);
 291
 292                         /* due to ABI compat need to split into hi/lo */
 293                         fe->port_no = f->dst->port_no;
 294                         fe->port_hi = f->dst->port_no >> 8;
 295
 296                         fe->is_local = f->is_local;
 297                         if (!f->is_static)
 298                                 fe->ageing_timer_value = jiffies_to_clock_t(jiffies - f->updated);
 299                         ++fe;
 300                         ++num;
 301                 }
 302         }
 303
 304  out:
 305         rcu_read_unlock();
 306
 307         return num;
 308 }
 309
 310 static struct net_bridge_fdb_entry *fdb_find(struct hlist_head *head,
 311                                              const unsigned char *addr)
 312 {
 313         struct hlist_node *h;
 314         struct net_bridge_fdb_entry *fdb;
 315
 316         hlist_for_each_entry(fdb, h, head, hlist) {
 317                 if (!compare_ether_addr(fdb->addr.addr, addr))
 318                         return fdb;
 319         }
 320         return NULL;
 321 }
 322
 323 static struct net_bridge_fdb_entry *fdb_find_rcu(struct hlist_head *head,
 324                                                  const unsigned char *addr)
 325 {
 326         struct hlist_node *h;
 327         struct net_bridge_fdb_entry *fdb;
 328
 329         hlist_for_each_entry_rcu(fdb, h, head, hlist) {
 330                 if (!compare_ether_addr(fdb->addr.addr, addr))
 331                         return fdb;
 332         }
 333         return NULL;
 334 }
 335
 336 static struct net_bridge_fdb_entry *fdb_create(struct hlist_head *head,
 337                                                struct net_bridge_port *source,
 338                                                const unsigned char *addr)
 339 {
 340         struct net_bridge_fdb_entry *fdb;
 341
 342         fdb = kmem_cache_alloc(br_fdb_cache, GFP_ATOMIC);
 343         if (fdb) {
 344                 memcpy(fdb->addr.addr, addr, ETH_ALEN);
 345                 fdb->dst = source;
 346                 fdb->is_local = 0;
 347                 fdb->is_static = 0;
 348                 fdb->updated = fdb->used = jiffies;
 349                 hlist_add_head_rcu(&fdb->hlist, head);
 350                 fdb_notify(fdb, RTM_NEWNEIGH);
 351         }
 352         return fdb;
 353 }
 354
 355 static int fdb_insert(struct net_bridge *br, struct net_bridge_port *source,
 356                   const unsigned char *addr)
 357 {
 358         struct hlist_head *head = &br->hash[br_mac_hash(addr)];
 359         struct net_bridge_fdb_entry *fdb;
 360
 361         if (!is_valid_ether_addr(addr))
 362                 return -EINVAL;
 363
 364         fdb = fdb_find(head, addr);
 365         if (fdb) {
 366                 /* it is okay to have multiple ports with same
 367                  * address, just use the first one.
 368                  */
 369                 if (fdb->is_local)
 370                         return 0;
 371                 br_warn(br, "adding interface %s with same address "
 372                        "as a received packet\n",
 373                        source->dev->name);
 374                 fdb_delete(fdb);
 375         }
 376
 377         fdb = fdb_create(head, source, addr);
 378         if (!fdb)
 379                 return -ENOMEM;
 380
 381         fdb->is_local = fdb->is_static = 1;
 382         return 0;
 383 }
 384
 385 /* Add entry for local address of interface */
 386 int br_fdb_insert(struct net_bridge *br, struct net_bridge_port *source,
 387                   const unsigned char *addr)
 388 {
 389         int ret;
 390
 391         spin_lock_bh(&br->hash_lock);
 392         ret = fdb_insert(br, source, addr);
 393         spin_unlock_bh(&br->hash_lock);
 394         return ret;
 395 }
 396
 397 void br_fdb_update(struct net_bridge *br, struct net_bridge_port *source,
 398                    const unsigned char *addr)
 399 {
 400         struct hlist_head *head = &br->hash[br_mac_hash(addr)];
 401         struct net_bridge_fdb_entry *fdb;
 402
 403         /* some users want to always flood. */
 404         if (hold_time(br) == 0)
 405                 return;
 406
 407         /* ignore packets unless we are using this port */
 408         if (!(source->state == BR_STATE_LEARNING ||
 409               source->state == BR_STATE_FORWARDING))
 410                 return;
 411
 412         fdb = fdb_find_rcu(head, addr);
 413         if (likely(fdb)) {
 414                 /* attempt to update an entry for a local interface */
 415                 if (unlikely(fdb->is_local)) {
 416                         if (net_ratelimit())
 417                                 br_warn(br, "received packet on %s with "
 418                                         "own address as source address\n",
 419                                         source->dev->name);
 420                 } else {
 421                         /* fastpath: update of existing entry */
 422                         fdb->dst = source;
 423                         fdb->updated = jiffies;
 424                 }
 425         } else {
 426                 spin_lock(&br->hash_lock);
 427                 if (likely(!fdb_find(head, addr)))
 428                         fdb_create(head, source, addr);
 429
 430                 /* else  we lose race and someone else inserts
 431                  * it first, don't bother updating
 432                  */
 433                 spin_unlock(&br->hash_lock);
 434         }
 435 }
 436
 437 static int fdb_to_nud(const struct net_bridge_fdb_entry *fdb)
 438 {
 439         if (fdb->is_local)
 440                 return NUD_PERMANENT;
 441         else if (fdb->is_static)
 442                 return NUD_NOARP;
 443         else if (has_expired(fdb->dst->br, fdb))
 444                 return NUD_STALE;
 445         else
 446                 return NUD_REACHABLE;
 447 }
 448
 449 static int fdb_fill_info(struct sk_buff *skb,
 450                          const struct net_bridge_fdb_entry *fdb,
 451                          u32 pid, u32 seq, int type, unsigned int flags)
 452 {
 453         unsigned long now = jiffies;
 454         struct nda_cacheinfo ci;
 455         struct nlmsghdr *nlh;
 456         struct ndmsg *ndm;
 457
 458         nlh = nlmsg_put(skb, pid, seq, type, sizeof(*ndm), flags);
 459         if (nlh == NULL)
 460                 return -EMSGSIZE;
 461
 462
 463         ndm = nlmsg_data(nlh);
 464         ndm->ndm_family  = AF_BRIDGE;
 465         ndm->ndm_pad1    = 0;
 466         ndm->ndm_pad2    = 0;
 467         ndm->ndm_flags   = 0;
 468         ndm->ndm_type    = 0;
 469         ndm->ndm_ifindex = fdb->dst->dev->ifindex;
 470         ndm->ndm_state   = fdb_to_nud(fdb);
 471
 472         NLA_PUT(skb, NDA_LLADDR, ETH_ALEN, &fdb->addr);
 473
 474         ci.ndm_used      = jiffies_to_clock_t(now - fdb->used);
 475         ci.ndm_confirmed = 0;
 476         ci.ndm_updated   = jiffies_to_clock_t(now - fdb->updated);
 477         ci.ndm_refcnt    = 0;
 478         NLA_PUT(skb, NDA_CACHEINFO, sizeof(ci), &ci);
 479
 480         return nlmsg_end(skb, nlh);
 481
 482 nla_put_failure:
 483         nlmsg_cancel(skb, nlh);
 484         return -EMSGSIZE;
 485 }
 486
 487 static inline size_t fdb_nlmsg_size(void)
 488 {
 489         return NLMSG_ALIGN(sizeof(struct ndmsg))
 490                 + nla_total_size(ETH_ALEN) /* NDA_LLADDR */
 491                 + nla_total_size(sizeof(struct nda_cacheinfo));
 492 }
 493
 494 static void fdb_notify(const struct net_bridge_fdb_entry *fdb, int type)
 495 {
 496         struct net *net = dev_net(fdb->dst->dev);
 497         struct sk_buff *skb;
 498         int err = -ENOBUFS;
 499
 500         skb = nlmsg_new(fdb_nlmsg_size(), GFP_ATOMIC);
 501         if (skb == NULL)
 502                 goto errout;
 503
 504         err = fdb_fill_info(skb, fdb, 0, 0, type, 0);
 505         if (err < 0) {
 506                 /* -EMSGSIZE implies BUG in fdb_nlmsg_size() */
 507                 WARN_ON(err == -EMSGSIZE);
 508                 kfree_skb(skb);
 509                 goto errout;
 510         }
 511         rtnl_notify(skb, net, 0, RTNLGRP_NEIGH, NULL, GFP_ATOMIC);
 512         return;
 513 errout:
 514         if (err < 0)
 515                 rtnl_set_sk_err(net, RTNLGRP_NEIGH, err);
 516 }
 517
 518 /* Dump information about entries, in response to GETNEIGH */
 519 int br_fdb_dump(struct sk_buff *skb, struct netlink_callback *cb)
 520 {
 521         struct net *net = sock_net(skb->sk);
 522         struct net_device *dev;
 523         int idx = 0;
 524
 525         rcu_read_lock();
 526         for_each_netdev_rcu(net, dev) {
 527                 struct net_bridge *br = netdev_priv(dev);
 528                 int i;
 529
 530                 if (!(dev->priv_flags & IFF_EBRIDGE))
 531                         continue;
 532
 533                 for (i = 0; i < BR_HASH_SIZE; i++) {
 534                         struct hlist_node *h;
 535                         struct net_bridge_fdb_entry *f;
 536
 537                         hlist_for_each_entry_rcu(f, h, &br->hash[i], hlist) {
 538                                 if (idx < cb->args[0])
 539                                         goto skip;
 540
 541                                 if (fdb_fill_info(skb, f,
 542                                                   NETLINK_CB(cb->skb).pid,
 543                                                   cb->nlh->nlmsg_seq,
 544                                                   RTM_NEWNEIGH,
 545                                                   NLM_F_MULTI) < 0)
 546                                         break;
 547 skip:
 548                                 ++idx;
 549                         }
 550                 }
 551         }
 552         rcu_read_unlock();
 553
 554         cb->args[0] = idx;
 555
 556         return skb->len;
 557 }
 558
 559 /* Create new static fdb entry */
 560 static int fdb_add_entry(struct net_bridge_port *source, const __u8 *addr,
 561                          __u16 state)
 562 {
 563         struct net_bridge *br = source->br;
 564         struct hlist_head *head = &br->hash[br_mac_hash(addr)];
 565         struct net_bridge_fdb_entry *fdb;
 566
 567         fdb = fdb_find(head, addr);
 568         if (fdb)
 569                 return -EEXIST;
 570
 571         fdb = fdb_create(head, source, addr);
 572         if (!fdb)
 573                 return -ENOMEM;
 574
 575         if (state & NUD_PERMANENT)
 576                 fdb->is_local = fdb->is_static = 1;
 577         else if (state & NUD_NOARP)
 578                 fdb->is_static = 1;
 579         return 0;
 580 }
 581
 582 /* Add new permanent fdb entry with RTM_NEWNEIGH */
 583 int br_fdb_add(struct sk_buff *skb, struct nlmsghdr *nlh, void *arg)
 584 {
 585         struct net *net = sock_net(skb->sk);
 586         struct ndmsg *ndm;
 587         struct nlattr *tb[NDA_MAX+1];
 588         struct net_device *dev;
 589         struct net_bridge_port *p;
 590         const __u8 *addr;
 591         int err;
 592
 593         ASSERT_RTNL();
 594         err = nlmsg_parse(nlh, sizeof(*ndm), tb, NDA_MAX, NULL);
 595         if (err < 0)
 596                 return err;
 597
 598         ndm = nlmsg_data(nlh);
 599         if (ndm->ndm_ifindex == 0) {
 600                 pr_info("bridge: RTM_NEWNEIGH with invalid ifindex\n");
 601                 return -EINVAL;
 602         }
 603
 604         dev = __dev_get_by_index(net, ndm->ndm_ifindex);
 605         if (dev == NULL) {
 606                 pr_info("bridge: RTM_NEWNEIGH with unknown ifindex\n");
 607                 return -ENODEV;
 608         }
 609
 610         if (!tb[NDA_LLADDR] || nla_len(tb[NDA_LLADDR]) != ETH_ALEN) {
 611                 pr_info("bridge: RTM_NEWNEIGH with invalid address\n");
 612                 return -EINVAL;
 613         }
 614
 615         addr = nla_data(tb[NDA_LLADDR]);
 616         if (!is_valid_ether_addr(addr)) {
 617                 pr_info("bridge: RTM_NEWNEIGH with invalid ether address\n");
 618                 return -EINVAL;
 619         }
 620
 621         p = br_port_get_rtnl(dev);
 622         if (p == NULL) {
 623                 pr_info("bridge: RTM_NEWNEIGH %s not a bridge port\n",
 624                         dev->name);
 625                 return -EINVAL;
 626         }
 627
 628         spin_lock_bh(&p->br->hash_lock);
 629         err = fdb_add_entry(p, addr, ndm->ndm_state);
 630         spin_unlock_bh(&p->br->hash_lock);
 631
 632         return err;
 633 }
 634
 635 static int fdb_delete_by_addr(struct net_bridge_port *p, const u8 *addr)
 636 {
 637         struct net_bridge *br = p->br;
 638         struct hlist_head *head = &br->hash[br_mac_hash(addr)];
 639         struct net_bridge_fdb_entry *fdb;
 640
 641         fdb = fdb_find(head, addr);
 642         if (!fdb)
 643                 return -ENOENT;
 644
 645         fdb_delete(fdb);
 646         return 0;
 647 }
 648
 649 /* Remove neighbor entry with RTM_DELNEIGH */
 650 int br_fdb_delete(struct sk_buff *skb, struct nlmsghdr *nlh, void *arg)
 651 {
 652         struct net *net = sock_net(skb->sk);
 653         struct ndmsg *ndm;
 654         struct net_bridge_port *p;
 655         struct nlattr *llattr;
 656         const __u8 *addr;
 657         struct net_device *dev;
 658         int err;
 659
 660         ASSERT_RTNL();
 661         if (nlmsg_len(nlh) < sizeof(*ndm))
 662                 return -EINVAL;
 663
 664         ndm = nlmsg_data(nlh);
 665         if (ndm->ndm_ifindex == 0) {
 666                 pr_info("bridge: RTM_DELNEIGH with invalid ifindex\n");
 667                 return -EINVAL;
 668         }
 669
 670         dev = __dev_get_by_index(net, ndm->ndm_ifindex);
 671         if (dev == NULL) {
 672                 pr_info("bridge: RTM_DELNEIGH with unknown ifindex\n");
 673                 return -ENODEV;
 674         }
 675
 676         llattr = nlmsg_find_attr(nlh, sizeof(*ndm), NDA_LLADDR);
 677         if (llattr == NULL || nla_len(llattr) != ETH_ALEN) {
 678                 pr_info("bridge: RTM_DELNEIGH with invalid address\n");
 679                 return -EINVAL;
 680         }
 681
 682         addr = nla_data(llattr);
 683
 684         p = br_port_get_rtnl(dev);
 685         if (p == NULL) {
 686                 pr_info("bridge: RTM_DELNEIGH %s not a bridge port\n",
 687                         dev->name);
 688                 return -EINVAL;
 689         }
 690
 691         spin_lock_bh(&p->br->hash_lock);
 692         err = fdb_delete_by_addr(p, addr);
 693         spin_unlock_bh(&p->br->hash_lock);
 694
 695         return err;
 696 }