sys/netgraph/ng_bridge.c

   1 /*-
   2  * Copyright (c) 2000 Whistle Communications, Inc.
   3  * All rights reserved.
   4  *
   5  * Subject to the following obligations and disclaimer of warranty, use and
   6  * redistribution of this software, in source or object code forms, with or
   7  * without modifications are expressly permitted by Whistle Communications;
   8  * provided, however, that:
   9  * 1. Any and all reproductions of the source or object code must include the
  10  *    copyright notice above and the following disclaimer of warranties; and
  11  * 2. No rights are granted, in any manner or form, to use Whistle
  12  *    Communications, Inc. trademarks, including the mark "WHISTLE
  13  *    COMMUNICATIONS" on advertising, endorsements, or otherwise except as
  14  *    such appears in the above copyright notice or in the software.
  15  *
  16  * THIS SOFTWARE IS BEING PROVIDED BY WHISTLE COMMUNICATIONS "AS IS", AND
  17  * TO THE MAXIMUM EXTENT PERMITTED BY LAW, WHISTLE COMMUNICATIONS MAKES NO
  18  * REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED, REGARDING THIS SOFTWARE,
  19  * INCLUDING WITHOUT LIMITATION, ANY AND ALL IMPLIED WARRANTIES OF
  20  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT.
  21  * WHISTLE COMMUNICATIONS DOES NOT WARRANT, GUARANTEE, OR MAKE ANY
  22  * REPRESENTATIONS REGARDING THE USE OF, OR THE RESULTS OF THE USE OF THIS
  23  * SOFTWARE IN TERMS OF ITS CORRECTNESS, ACCURACY, RELIABILITY OR OTHERWISE.
  24  * IN NO EVENT SHALL WHISTLE COMMUNICATIONS BE LIABLE FOR ANY DAMAGES
  25  * RESULTING FROM OR ARISING OUT OF ANY USE OF THIS SOFTWARE, INCLUDING
  26  * WITHOUT LIMITATION, ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
  27  * PUNITIVE, OR CONSEQUENTIAL DAMAGES, PROCUREMENT OF SUBSTITUTE GOODS OR
  28  * SERVICES, LOSS OF USE, DATA OR PROFITS, HOWEVER CAUSED AND UNDER ANY
  29  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  30  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  31  * THIS SOFTWARE, EVEN IF WHISTLE COMMUNICATIONS IS ADVISED OF THE POSSIBILITY
  32  * OF SUCH DAMAGE.
  33  *
  34  * Author: Archie Cobbs <archie@freebsd.org>
  35  *
  36  * $FreeBSD$
  37  */
  38
  39 /*
  40  * ng_bridge(4) netgraph node type
  41  *
  42  * The node performs standard intelligent Ethernet bridging over
  43  * each of its connected hooks, or links.  A simple loop detection
  44  * algorithm is included which disables a link for priv->conf.loopTimeout
  45  * seconds when a host is seen to have jumped from one link to
  46  * another within priv->conf.minStableAge seconds.
  47  *
  48  * We keep a hashtable that maps Ethernet addresses to host info,
  49  * which is contained in struct ng_bridge_host's. These structures
  50  * tell us on which link the host may be found. A host's entry will
  51  * expire after priv->conf.maxStaleness seconds.
  52  *
  53  * This node is optimzed for stable networks, where machines jump
  54  * from one port to the other only rarely.
  55  */
  56
  57 #include <sys/param.h>
  58 #include <sys/systm.h>
  59 #include <sys/kernel.h>
  60 #include <sys/lock.h>
  61 #include <sys/malloc.h>
  62 #include <sys/mbuf.h>
  63 #include <sys/errno.h>
  64 #include <sys/rwlock.h>
  65 #include <sys/syslog.h>
  66 #include <sys/socket.h>
  67 #include <sys/ctype.h>
  68 #include <sys/types.h>
  69 #include <sys/counter.h>
  70
  71 #include <net/if.h>
  72 #include <net/if_var.h>
  73 #include <net/ethernet.h>
  74 #include <net/vnet.h>
  75
  76 #include <netinet/in.h>
  77 #include <netgraph/ng_message.h>
  78 #include <netgraph/netgraph.h>
  79 #include <netgraph/ng_parse.h>
  80 #include <netgraph/ng_bridge.h>
  81
  82 #ifdef NG_SEPARATE_MALLOC
  83 static MALLOC_DEFINE(M_NETGRAPH_BRIDGE, "netgraph_bridge",
  84     "netgraph bridge node");
  85 #else
  86 #define M_NETGRAPH_BRIDGE M_NETGRAPH
  87 #endif
  88
  89 /* Counter based stats */
  90 struct ng_bridge_link_kernel_stats {
  91         counter_u64_t   recvOctets;     /* total octets rec'd on link */
  92         counter_u64_t   recvPackets;    /* total pkts rec'd on link */
  93         counter_u64_t   recvMulticasts; /* multicast pkts rec'd on link */
  94         counter_u64_t   recvBroadcasts; /* broadcast pkts rec'd on link */
  95         counter_u64_t   recvUnknown;    /* pkts rec'd with unknown dest addr */
  96         counter_u64_t   recvRunts;      /* pkts rec'd less than 14 bytes */
  97         counter_u64_t   recvInvalid;    /* pkts rec'd with bogus source addr */
  98         counter_u64_t   xmitOctets;     /* total octets xmit'd on link */
  99         counter_u64_t   xmitPackets;    /* total pkts xmit'd on link */
 100         counter_u64_t   xmitMulticasts; /* multicast pkts xmit'd on link */
 101         counter_u64_t   xmitBroadcasts; /* broadcast pkts xmit'd on link */
 102         counter_u64_t   loopDrops;      /* pkts dropped due to loopback */
 103         u_int64_t       loopDetects;    /* number of loop detections */
 104         counter_u64_t   memoryFailures; /* times couldn't get mem or mbuf */
 105 };
 106
 107 /* Per-link private data */
 108 struct ng_bridge_link {
 109         hook_p                          hook;           /* netgraph hook */
 110         u_int16_t                       loopCount;      /* loop ignore timer */
 111         unsigned int                    learnMac : 1,   /* autolearn macs */
 112                                         sendUnknown : 1;/* send unknown macs out */
 113         struct ng_bridge_link_kernel_stats stats;       /* link stats */
 114 };
 115 typedef struct ng_bridge_link const *link_cp;   /* read only access */
 116
 117 /* Per-node private data */
 118 struct ng_bridge_private {
 119         struct ng_bridge_bucket *tab;           /* hash table bucket array */
 120         struct ng_bridge_config conf;           /* node configuration */
 121         node_p                  node;           /* netgraph node */
 122         u_int                   numHosts;       /* num entries in table */
 123         u_int                   numBuckets;     /* num buckets in table */
 124         u_int                   hashMask;       /* numBuckets - 1 */
 125         int                     numLinks;       /* num connected links */
 126         unsigned int            persistent : 1, /* can exist w/o hooks */
 127                                 sendUnknown : 1;/* links receive unknowns by default */
 128         struct callout          timer;          /* one second periodic timer */
 129 };
 130 typedef struct ng_bridge_private *priv_p;
 131 typedef struct ng_bridge_private const *priv_cp;        /* read only access */
 132
 133 /* Information about a host, stored in a hash table entry */
 134 struct ng_bridge_host {
 135         u_char          addr[6];        /* ethernet address */
 136         link_p          link;           /* link where addr can be found */
 137         u_int16_t       age;            /* seconds ago entry was created */
 138         u_int16_t       staleness;      /* seconds ago host last heard from */
 139         SLIST_ENTRY(ng_bridge_host)     next;   /* next entry in bucket */
 140 };
 141
 142 /* Hash table bucket declaration */
 143 SLIST_HEAD(ng_bridge_bucket, ng_bridge_host);
 144
 145 /* Netgraph node methods */
 146 static ng_constructor_t ng_bridge_constructor;
 147 static ng_rcvmsg_t      ng_bridge_rcvmsg;
 148 static ng_shutdown_t    ng_bridge_shutdown;
 149 static ng_newhook_t     ng_bridge_newhook;
 150 static ng_rcvdata_t     ng_bridge_rcvdata;
 151 static ng_disconnect_t  ng_bridge_disconnect;
 152
 153 /* Other internal functions */
 154 static void     ng_bridge_free_link(link_p link);
 155 static struct   ng_bridge_host *ng_bridge_get(priv_cp priv, const u_char *addr);
 156 static int      ng_bridge_put(priv_p priv, const u_char *addr, link_p link);
 157 static void     ng_bridge_rehash(priv_p priv);
 158 static void     ng_bridge_remove_hosts(priv_p priv, link_p link);
 159 static void     ng_bridge_timeout(node_p node, hook_p hook, void *arg1, int arg2);
 160 static const    char *ng_bridge_nodename(node_cp node);
 161
 162 /* Ethernet broadcast */
 163 static const u_char ng_bridge_bcast_addr[ETHER_ADDR_LEN] =
 164     { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
 165
 166 /* Compare Ethernet addresses using 32 and 16 bit words instead of bytewise */
 167 #define ETHER_EQUAL(a,b)        (((const u_int32_t *)(a))[0] \
 168                                         == ((const u_int32_t *)(b))[0] \
 169                                     && ((const u_int16_t *)(a))[2] \
 170                                         == ((const u_int16_t *)(b))[2])
 171
 172 /* Minimum and maximum number of hash buckets. Must be a power of two. */
 173 #define MIN_BUCKETS             (1 << 5)        /* 32 */
 174 #define MAX_BUCKETS             (1 << 14)       /* 16384 */
 175
 176 /* Configuration default values */
 177 #define DEFAULT_LOOP_TIMEOUT    60
 178 #define DEFAULT_MAX_STALENESS   (15 * 60)       /* same as ARP timeout */
 179 #define DEFAULT_MIN_STABLE_AGE  1
 180
 181 /******************************************************************
 182                     NETGRAPH PARSE TYPES
 183 ******************************************************************/
 184
 185 /*
 186  * How to determine the length of the table returned by NGM_BRIDGE_GET_TABLE
 187  */
 188 static int
 189 ng_bridge_getTableLength(const struct ng_parse_type *type,
 190         const u_char *start, const u_char *buf)
 191 {
 192         const struct ng_bridge_host_ary *const hary
 193             = (const struct ng_bridge_host_ary *)(buf - sizeof(u_int32_t));
 194
 195         return hary->numHosts;
 196 }
 197
 198 /* Parse type for struct ng_bridge_host_ary */
 199 static const struct ng_parse_struct_field ng_bridge_host_type_fields[]
 200         = NG_BRIDGE_HOST_TYPE_INFO(&ng_parse_enaddr_type);
 201 static const struct ng_parse_type ng_bridge_host_type = {
 202         &ng_parse_struct_type,
 203         &ng_bridge_host_type_fields
 204 };
 205 static const struct ng_parse_array_info ng_bridge_hary_type_info = {
 206         &ng_bridge_host_type,
 207         ng_bridge_getTableLength
 208 };
 209 static const struct ng_parse_type ng_bridge_hary_type = {
 210         &ng_parse_array_type,
 211         &ng_bridge_hary_type_info
 212 };
 213 static const struct ng_parse_struct_field ng_bridge_host_ary_type_fields[]
 214         = NG_BRIDGE_HOST_ARY_TYPE_INFO(&ng_bridge_hary_type);
 215 static const struct ng_parse_type ng_bridge_host_ary_type = {
 216         &ng_parse_struct_type,
 217         &ng_bridge_host_ary_type_fields
 218 };
 219
 220 /* Parse type for struct ng_bridge_config */
 221 static const struct ng_parse_struct_field ng_bridge_config_type_fields[]
 222         = NG_BRIDGE_CONFIG_TYPE_INFO;
 223 static const struct ng_parse_type ng_bridge_config_type = {
 224         &ng_parse_struct_type,
 225         &ng_bridge_config_type_fields
 226 };
 227
 228 /* Parse type for struct ng_bridge_link_stat */
 229 static const struct ng_parse_struct_field ng_bridge_stats_type_fields[]
 230         = NG_BRIDGE_STATS_TYPE_INFO;
 231 static const struct ng_parse_type ng_bridge_stats_type = {
 232         &ng_parse_struct_type,
 233         &ng_bridge_stats_type_fields
 234 };
 235 /* Parse type for struct ng_bridge_move_host */
 236 static const struct ng_parse_struct_field ng_bridge_move_host_type_fields[]
 237         = NG_BRIDGE_MOVE_HOST_TYPE_INFO(&ng_parse_enaddr_type);
 238 static const struct ng_parse_type ng_bridge_move_host_type = {
 239         &ng_parse_struct_type,
 240         &ng_bridge_move_host_type_fields
 241 };
 242
 243 /* List of commands and how to convert arguments to/from ASCII */
 244 static const struct ng_cmdlist ng_bridge_cmdlist[] = {
 245         {
 246           NGM_BRIDGE_COOKIE,
 247           NGM_BRIDGE_SET_CONFIG,
 248           "setconfig",
 249           &ng_bridge_config_type,
 250           NULL
 251         },
 252         {
 253           NGM_BRIDGE_COOKIE,
 254           NGM_BRIDGE_GET_CONFIG,
 255           "getconfig",
 256           NULL,
 257           &ng_bridge_config_type
 258         },
 259         {
 260           NGM_BRIDGE_COOKIE,
 261           NGM_BRIDGE_RESET,
 262           "reset",
 263           NULL,
 264           NULL
 265         },
 266         {
 267           NGM_BRIDGE_COOKIE,
 268           NGM_BRIDGE_GET_STATS,
 269           "getstats",
 270           &ng_parse_uint32_type,
 271           &ng_bridge_stats_type
 272         },
 273         {
 274           NGM_BRIDGE_COOKIE,
 275           NGM_BRIDGE_CLR_STATS,
 276           "clrstats",
 277           &ng_parse_uint32_type,
 278           NULL
 279         },
 280         {
 281           NGM_BRIDGE_COOKIE,
 282           NGM_BRIDGE_GETCLR_STATS,
 283           "getclrstats",
 284           &ng_parse_uint32_type,
 285           &ng_bridge_stats_type
 286         },
 287         {
 288           NGM_BRIDGE_COOKIE,
 289           NGM_BRIDGE_GET_TABLE,
 290           "gettable",
 291           NULL,
 292           &ng_bridge_host_ary_type
 293         },
 294         {
 295           NGM_BRIDGE_COOKIE,
 296           NGM_BRIDGE_SET_PERSISTENT,
 297           "setpersistent",
 298           NULL,
 299           NULL
 300         },
 301         {
 302           NGM_BRIDGE_COOKIE,
 303           NGM_BRIDGE_MOVE_HOST,
 304           "movehost",
 305           &ng_bridge_move_host_type,
 306           NULL
 307         },
 308         { 0 }
 309 };
 310
 311 /* Node type descriptor */
 312 static struct ng_type ng_bridge_typestruct = {
 313         .version =      NG_ABI_VERSION,
 314         .name =         NG_BRIDGE_NODE_TYPE,
 315         .constructor =  ng_bridge_constructor,
 316         .rcvmsg =       ng_bridge_rcvmsg,
 317         .shutdown =     ng_bridge_shutdown,
 318         .newhook =      ng_bridge_newhook,
 319         .rcvdata =      ng_bridge_rcvdata,
 320         .disconnect =   ng_bridge_disconnect,
 321         .cmdlist =      ng_bridge_cmdlist,
 322 };
 323 NETGRAPH_INIT(bridge, &ng_bridge_typestruct);
 324
 325 /******************************************************************
 326                     NETGRAPH NODE METHODS
 327 ******************************************************************/
 328
 329 /*
 330  * Node constructor
 331  */
 332 static int
 333 ng_bridge_constructor(node_p node)
 334 {
 335         priv_p priv;
 336
 337         /* Allocate and initialize private info */
 338         priv = malloc(sizeof(*priv), M_NETGRAPH_BRIDGE, M_WAITOK | M_ZERO);
 339         ng_callout_init(&priv->timer);
 340
 341         /* Allocate and initialize hash table, etc. */
 342         priv->tab = malloc(MIN_BUCKETS * sizeof(*priv->tab),
 343             M_NETGRAPH_BRIDGE, M_WAITOK | M_ZERO);
 344         priv->numBuckets = MIN_BUCKETS;
 345         priv->hashMask = MIN_BUCKETS - 1;
 346         priv->conf.debugLevel = 1;
 347         priv->conf.loopTimeout = DEFAULT_LOOP_TIMEOUT;
 348         priv->conf.maxStaleness = DEFAULT_MAX_STALENESS;
 349         priv->conf.minStableAge = DEFAULT_MIN_STABLE_AGE;
 350         priv->sendUnknown = 1;         /* classic bridge */
 351
 352         NG_NODE_SET_PRIVATE(node, priv);
 353         priv->node = node;
 354
 355         /* Start timer; timer is always running while node is alive */
 356         ng_callout(&priv->timer, node, NULL, hz, ng_bridge_timeout, NULL, 0);
 357
 358         /* Done */
 359         return (0);
 360 }
 361
 362 /*
 363  * Method for attaching a new hook
 364  */
 365 static  int
 366 ng_bridge_newhook(node_p node, hook_p hook, const char *name)
 367 {
 368         const priv_p priv = NG_NODE_PRIVATE(node);
 369         char linkName[NG_HOOKSIZ];
 370         u_int32_t linkNum;
 371         link_p link;
 372         const char *prefix = NG_BRIDGE_HOOK_LINK_PREFIX;
 373         bool isUplink;
 374
 375         /* Check for a link hook */
 376         if (strlen(name) <= strlen(prefix))
 377                 return (EINVAL);       /* Unknown hook name */
 378
 379         isUplink = (name[0] == 'u');
 380         if (isUplink)
 381                 prefix = NG_BRIDGE_HOOK_UPLINK_PREFIX;
 382
 383         /* primitive parsing */
 384         linkNum = strtoul(name + strlen(prefix), NULL, 10);
 385         /* validation by comparing against the reconstucted name  */
 386         snprintf(linkName, sizeof(linkName), "%s%u", prefix, linkNum);
 387         if (strcmp(linkName, name) != 0)
 388                 return (EINVAL);
 389
 390         if (linkNum == 0 && isUplink)
 391                 return (EINVAL);
 392
 393         if(NG_PEER_NODE(hook) == node)
 394                 return (ELOOP);
 395
 396         link = malloc(sizeof(*link), M_NETGRAPH_BRIDGE, M_NOWAIT | M_ZERO);
 397         if (link == NULL)
 398                 return (ENOMEM);
 399
 400 #define NG_BRIDGE_COUNTER_ALLOC(f) do {                 \
 401         link->stats.f = counter_u64_alloc(M_NOWAIT);    \
 402         if (link->stats.f == NULL)                      \
 403                 goto nomem;                             \
 404 } while (0)
 405         NG_BRIDGE_COUNTER_ALLOC(recvOctets);
 406         NG_BRIDGE_COUNTER_ALLOC(recvPackets);
 407         NG_BRIDGE_COUNTER_ALLOC(recvMulticasts);
 408         NG_BRIDGE_COUNTER_ALLOC(recvBroadcasts);
 409         NG_BRIDGE_COUNTER_ALLOC(recvUnknown);
 410         NG_BRIDGE_COUNTER_ALLOC(recvRunts);
 411         NG_BRIDGE_COUNTER_ALLOC(recvInvalid);
 412         NG_BRIDGE_COUNTER_ALLOC(xmitOctets);
 413         NG_BRIDGE_COUNTER_ALLOC(xmitPackets);
 414         NG_BRIDGE_COUNTER_ALLOC(xmitMulticasts);
 415         NG_BRIDGE_COUNTER_ALLOC(xmitBroadcasts);
 416         NG_BRIDGE_COUNTER_ALLOC(loopDrops);
 417         NG_BRIDGE_COUNTER_ALLOC(memoryFailures);
 418 #undef NG_BRIDGE_COUNTER_ALLOC
 419
 420         link->hook = hook;
 421         if (isUplink) {
 422                 link->learnMac = 0;
 423                 link->sendUnknown = 1;
 424                 if (priv->numLinks == 0)        /* if the first link is an uplink */
 425                         priv->sendUnknown = 0;  /* switch to restrictive mode */
 426         } else {
 427                 link->learnMac = 1;
 428                 link->sendUnknown = priv->sendUnknown;
 429         }
 430
 431         NG_HOOK_SET_PRIVATE(hook, link);
 432         priv->numLinks++;
 433         return (0);
 434
 435 nomem:
 436         ng_bridge_free_link(link);
 437         return (ENOMEM);
 438 }
 439
 440 /*
 441  * Receive a control message
 442  */
 443 static void
 444 ng_bridge_clear_link_stats(struct ng_bridge_link_kernel_stats *p)
 445 {
 446         counter_u64_zero(p->recvOctets);
 447         counter_u64_zero(p->recvPackets);
 448         counter_u64_zero(p->recvMulticasts);
 449         counter_u64_zero(p->recvBroadcasts);
 450         counter_u64_zero(p->recvUnknown);
 451         counter_u64_zero(p->recvRunts);
 452         counter_u64_zero(p->recvInvalid);
 453         counter_u64_zero(p->xmitOctets);
 454         counter_u64_zero(p->xmitPackets);
 455         counter_u64_zero(p->xmitMulticasts);
 456         counter_u64_zero(p->xmitBroadcasts);
 457         counter_u64_zero(p->loopDrops);
 458         p->loopDetects = 0;
 459         counter_u64_zero(p->memoryFailures);
 460 }
 461
 462 static void
 463 ng_bridge_free_link(link_p link)
 464 {
 465         counter_u64_free(link->stats.recvOctets);
 466         counter_u64_free(link->stats.recvPackets);
 467         counter_u64_free(link->stats.recvMulticasts);
 468         counter_u64_free(link->stats.recvBroadcasts);
 469         counter_u64_free(link->stats.recvUnknown);
 470         counter_u64_free(link->stats.recvRunts);
 471         counter_u64_free(link->stats.recvInvalid);
 472         counter_u64_free(link->stats.xmitOctets);
 473         counter_u64_free(link->stats.xmitPackets);
 474         counter_u64_free(link->stats.xmitMulticasts);
 475         counter_u64_free(link->stats.xmitBroadcasts);
 476         counter_u64_free(link->stats.loopDrops);
 477         counter_u64_free(link->stats.memoryFailures);
 478         free(link, M_NETGRAPH_BRIDGE);
 479 }
 480
 481 static int
 482 ng_bridge_reset_link(hook_p hook, void *arg __unused)
 483 {
 484         link_p priv = NG_HOOK_PRIVATE(hook);
 485
 486         priv->loopCount = 0;
 487         ng_bridge_clear_link_stats(&priv->stats);
 488         return (1);
 489 }
 490
 491 static int
 492 ng_bridge_rcvmsg(node_p node, item_p item, hook_p lasthook)
 493 {
 494         const priv_p priv = NG_NODE_PRIVATE(node);
 495         struct ng_mesg *resp = NULL;
 496         int error = 0;
 497         struct ng_mesg *msg;
 498
 499         NGI_GET_MSG(item, msg);
 500         switch (msg->header.typecookie) {
 501         case NGM_BRIDGE_COOKIE:
 502                 switch (msg->header.cmd) {
 503                 case NGM_BRIDGE_GET_CONFIG:
 504                     {
 505                         struct ng_bridge_config *conf;
 506
 507                         NG_MKRESPONSE(resp, msg,
 508                             sizeof(struct ng_bridge_config), M_NOWAIT);
 509                         if (resp == NULL) {
 510                                 error = ENOMEM;
 511                                 break;
 512                         }
 513                         conf = (struct ng_bridge_config *)resp->data;
 514                         *conf = priv->conf;     /* no sanity checking needed */
 515                         break;
 516                     }
 517                 case NGM_BRIDGE_SET_CONFIG:
 518                     {
 519                         struct ng_bridge_config *conf;
 520
 521                         if (msg->header.arglen
 522                             != sizeof(struct ng_bridge_config)) {
 523                                 error = EINVAL;
 524                                 break;
 525                         }
 526                         conf = (struct ng_bridge_config *)msg->data;
 527                         priv->conf = *conf;
 528                         break;
 529                     }
 530                 case NGM_BRIDGE_RESET:
 531                     {
 532                         /* Flush all entries in the hash table */
 533                         ng_bridge_remove_hosts(priv, NULL);
 534
 535                         /* Reset all loop detection counters and stats */
 536                         NG_NODE_FOREACH_HOOK(node, ng_bridge_reset_link, NULL);
 537                         break;
 538                     }
 539                 case NGM_BRIDGE_GET_STATS:
 540                 case NGM_BRIDGE_CLR_STATS:
 541                 case NGM_BRIDGE_GETCLR_STATS:
 542                     {
 543                         hook_p hook;
 544                         link_p link;
 545                         char linkName[NG_HOOKSIZ];
 546                         int linkNum;
 547
 548                         /* Get link number */
 549                         if (msg->header.arglen != sizeof(u_int32_t)) {
 550                                 error = EINVAL;
 551                                 break;
 552                         }
 553                         linkNum = *((int32_t *)msg->data);
 554                         if (linkNum < 0)
 555                                 snprintf(linkName, sizeof(linkName),
 556                                     "%s%u", NG_BRIDGE_HOOK_UPLINK_PREFIX, -linkNum);
 557                         else
 558                                 snprintf(linkName, sizeof(linkName),
 559                                     "%s%u", NG_BRIDGE_HOOK_LINK_PREFIX, linkNum);
 560
 561                         if ((hook = ng_findhook(node, linkName)) == NULL) {
 562                                 error = ENOTCONN;
 563                                 break;
 564                         }
 565                         link = NG_HOOK_PRIVATE(hook);
 566
 567                         /* Get/clear stats */
 568                         if (msg->header.cmd != NGM_BRIDGE_CLR_STATS) {
 569                                 struct ng_bridge_link_stats *rs;
 570
 571                                 NG_MKRESPONSE(resp, msg,
 572                                     sizeof(link->stats), M_NOWAIT);
 573                                 if (resp == NULL) {
 574                                         error = ENOMEM;
 575                                         break;
 576                                 }
 577                                 rs = (struct ng_bridge_link_stats *)resp->data;
 578 #define FETCH(x)        rs->x = counter_u64_fetch(link->stats.x)
 579                                 FETCH(recvOctets);
 580                                 FETCH(recvPackets);
 581                                 FETCH(recvMulticasts);
 582                                 FETCH(recvBroadcasts);
 583                                 FETCH(recvUnknown);
 584                                 FETCH(recvRunts);
 585                                 FETCH(recvInvalid);
 586                                 FETCH(xmitOctets);
 587                                 FETCH(xmitPackets);
 588                                 FETCH(xmitMulticasts);
 589                                 FETCH(xmitBroadcasts);
 590                                 FETCH(loopDrops);
 591                                 rs->loopDetects = link->stats.loopDetects;
 592                                 FETCH(memoryFailures);
 593 #undef FETCH
 594                         }
 595                         if (msg->header.cmd != NGM_BRIDGE_GET_STATS)
 596                                 ng_bridge_clear_link_stats(&link->stats);
 597                         break;
 598                     }
 599                 case NGM_BRIDGE_GET_TABLE:
 600                     {
 601                         struct ng_bridge_host_ary *ary;
 602                         struct ng_bridge_host *host;
 603                         int i = 0, bucket;
 604
 605                         NG_MKRESPONSE(resp, msg, sizeof(*ary)
 606                             + (priv->numHosts * sizeof(*ary->hosts)), M_NOWAIT);
 607                         if (resp == NULL) {
 608                                 error = ENOMEM;
 609                                 break;
 610                         }
 611                         ary = (struct ng_bridge_host_ary *)resp->data;
 612                         ary->numHosts = priv->numHosts;
 613                         for (bucket = 0; bucket < priv->numBuckets; bucket++) {
 614                                 SLIST_FOREACH(host, &priv->tab[bucket], next) {
 615                                         memcpy(ary->hosts[i].addr,
 616                                                host->addr,
 617                                                sizeof(ary->hosts[i].addr));
 618                                         ary->hosts[i].age       = host->age;
 619                                         ary->hosts[i].staleness = host->staleness;
 620                                         strncpy(ary->hosts[i].hook,
 621                                                 NG_HOOK_NAME(host->link->hook),
 622                                                 sizeof(ary->hosts[i].hook));
 623                                         i++;
 624                                 }
 625                         }
 626                         break;
 627                     }
 628                 case NGM_BRIDGE_SET_PERSISTENT:
 629                     {
 630                         priv->persistent = 1;
 631                         break;
 632                     }
 633                 case NGM_BRIDGE_MOVE_HOST:
 634                 {
 635                         struct ng_bridge_move_host *mh;
 636                         hook_p hook;
 637
 638                         if (msg->header.arglen < sizeof(*mh)) {
 639                                 error = EINVAL;
 640                                 break;
 641                         }
 642                         mh = (struct ng_bridge_move_host *)msg->data;
 643                         hook = (mh->hook[0] == 0)
 644                             ? lasthook
 645                             : ng_findhook(node, mh->hook);
 646                         if (hook == NULL) {
 647                                 error = ENOENT;
 648                                 break;
 649                         }
 650                         error = ng_bridge_put(priv, mh->addr, NG_HOOK_PRIVATE(hook));
 651                         break;
 652                 }
 653                 default:
 654                         error = EINVAL;
 655                         break;
 656                 }
 657                 break;
 658         default:
 659                 error = EINVAL;
 660                 break;
 661         }
 662
 663         /* Done */
 664         NG_RESPOND_MSG(error, node, item, resp);
 665         NG_FREE_MSG(msg);
 666         return (error);
 667 }
 668
 669 /*
 670  * Receive data on a hook
 671  */
 672 struct ng_bridge_send_ctx {
 673         link_p foundFirst, incoming;
 674         struct mbuf * m;
 675         int manycast, error;
 676 };
 677
 678 /*
 679  * Update stats and send out
 680  */
 681 static inline int
 682 ng_bridge_send_data(link_cp dst, int manycast, struct mbuf *m, item_p item) {
 683         int error = 0;
 684         size_t len = m->m_pkthdr.len;
 685
 686         if(item != NULL)
 687                 NG_FWD_NEW_DATA(error, item, dst->hook, m);
 688         else
 689                 NG_SEND_DATA_ONLY(error, dst->hook, m);
 690
 691         if (error) {
 692                 if (error == ENOMEM)
 693                         counter_u64_add(dst->stats.memoryFailures, 1);
 694                 /* The packet is still ours */
 695                 if (item != NULL)
 696                         NG_FREE_ITEM(item);
 697                 if (m != NULL)
 698                         NG_FREE_M(m);
 699                 return (error);
 700         }
 701
 702         counter_u64_add(dst->stats.xmitPackets, 1);
 703         counter_u64_add(dst->stats.xmitOctets, len);
 704         switch (manycast) {
 705         default:                       /* unknown unicast */
 706                 break;
 707         case 1:                        /* multicast */
 708                 counter_u64_add(dst->stats.xmitMulticasts, 1);
 709                 break;
 710         case 2:                        /* broadcast */
 711                 counter_u64_add(dst->stats.xmitBroadcasts, 1);
 712                 break;
 713         }
 714         return (0);
 715 }
 716
 717 /*
 718  * Loop body for sending to multiple destinations
 719  * return 0 to stop looping
 720  */
 721 static int
 722 ng_bridge_send_ctx(hook_p dst, void *arg)
 723 {
 724         struct ng_bridge_send_ctx *ctx = arg;
 725         link_p destLink = NG_HOOK_PRIVATE(dst);
 726         struct mbuf *m2 = NULL;
 727         int error = 0;
 728
 729         /* Skip incoming link */
 730         if (destLink == ctx->incoming) {
 731                 return (1);
 732         }
 733
 734         /* Skip sending unknowns to undesired links  */
 735         if (!ctx->manycast && !destLink->sendUnknown)
 736                 return (1);
 737
 738         if (ctx->foundFirst == NULL) {
 739                 /*
 740                  * This is the first usable link we have found.
 741                  * Reserve it for the originals.
 742                  * If we never find another we save a copy.
 743                  */
 744                 ctx->foundFirst = destLink;
 745                 return (1);
 746         }
 747
 748         /*
 749          * It's usable link but not the reserved (first) one.
 750          * Copy mbuf info for sending.
 751          */
 752         m2 = m_dup(ctx->m, M_NOWAIT);
 753         if (m2 == NULL) {
 754                 counter_u64_add(ctx->incoming->stats.memoryFailures, 1);
 755                 ctx->error = ENOBUFS;
 756                 return (0);            /* abort loop, do not try again and again */
 757         }
 758
 759         /* Send packet */
 760         error = ng_bridge_send_data(destLink, ctx->manycast, m2, NULL);
 761         if (error)
 762           ctx->error = error;
 763         return (1);
 764 }
 765
 766 static int
 767 ng_bridge_rcvdata(hook_p hook, item_p item)
 768 {
 769         const node_p node = NG_HOOK_NODE(hook);
 770         const priv_p priv = NG_NODE_PRIVATE(node);
 771         struct ng_bridge_host *host;
 772         struct ether_header *eh;
 773         struct ng_bridge_send_ctx ctx = { 0 };
 774
 775         NGI_GET_M(item, ctx.m);
 776
 777         ctx.incoming = NG_HOOK_PRIVATE(hook);
 778         /* Sanity check packet and pull up header */
 779         if (ctx.m->m_pkthdr.len < ETHER_HDR_LEN) {
 780                 counter_u64_add(ctx.incoming->stats.recvRunts, 1);
 781                 NG_FREE_ITEM(item);
 782                 NG_FREE_M(ctx.m);
 783                 return (EINVAL);
 784         }
 785         if (ctx.m->m_len < ETHER_HDR_LEN && !(ctx.m = m_pullup(ctx.m, ETHER_HDR_LEN))) {
 786                 counter_u64_add(ctx.incoming->stats.memoryFailures, 1);
 787                 NG_FREE_ITEM(item);
 788                 return (ENOBUFS);
 789         }
 790         eh = mtod(ctx.m, struct ether_header *);
 791         if ((eh->ether_shost[0] & 1) != 0) {
 792                 counter_u64_add(ctx.incoming->stats.recvInvalid, 1);
 793                 NG_FREE_ITEM(item);
 794                 NG_FREE_M(ctx.m);
 795                 return (EINVAL);
 796         }
 797
 798         /* Is link disabled due to a loopback condition? */
 799         if (ctx.incoming->loopCount != 0) {
 800                 counter_u64_add(ctx.incoming->stats.loopDrops, 1);
 801                 NG_FREE_ITEM(item);
 802                 NG_FREE_M(ctx.m);
 803                 return (ELOOP);
 804         }
 805
 806         /* Update stats */
 807         counter_u64_add(ctx.incoming->stats.recvPackets, 1);
 808         counter_u64_add(ctx.incoming->stats.recvOctets, ctx.m->m_pkthdr.len);
 809         if ((ctx.manycast = (eh->ether_dhost[0] & 1)) != 0) {
 810                 if (ETHER_EQUAL(eh->ether_dhost, ng_bridge_bcast_addr)) {
 811                         counter_u64_add(ctx.incoming->stats.recvBroadcasts, 1);
 812                         ctx.manycast = 2;
 813                 } else
 814                         counter_u64_add(ctx.incoming->stats.recvMulticasts, 1);
 815         }
 816
 817         /* Look up packet's source Ethernet address in hashtable */
 818         if ((host = ng_bridge_get(priv, eh->ether_shost)) != NULL)
 819                 /* Update time since last heard from this host.
 820                  * This is safe without locking, because it's
 821                  * the only operation during shared access.
 822                  */
 823                 if (__predict_false(host->staleness > 0))
 824                         host->staleness = 0;
 825
 826         if ((host == NULL && ctx.incoming->learnMac) ||
 827             (host != NULL && host->link != ctx.incoming)) {
 828                 struct ng_mesg *msg;
 829                 struct ng_bridge_move_host *mh;
 830                 int error = 0;
 831
 832                 NG_MKMESSAGE(msg, NGM_BRIDGE_COOKIE, NGM_BRIDGE_MOVE_HOST,
 833                     sizeof(*mh), M_NOWAIT);
 834                 if (msg == NULL) {
 835                         counter_u64_add(ctx.incoming->stats.memoryFailures, 1);
 836                         NG_FREE_ITEM(item);
 837                         NG_FREE_M(ctx.m);
 838                         return (ENOMEM);
 839                 }
 840                 mh = (struct ng_bridge_move_host *)msg->data;
 841                 strncpy(mh->hook, NG_HOOK_NAME(ctx.incoming->hook),
 842                     sizeof(mh->hook));
 843                 memcpy(mh->addr, eh->ether_shost, sizeof(mh->addr));
 844                 NG_SEND_MSG_ID(error, node, msg, NG_NODE_ID(node),
 845                     NG_NODE_ID(node));
 846                 if (error)
 847                         counter_u64_add(ctx.incoming->stats.memoryFailures, 1);
 848         }
 849
 850         if (host != NULL && host->link != ctx.incoming) {
 851                 if (host->age < priv->conf.minStableAge) {
 852                         /* Drop packet on instable links */
 853                         counter_u64_add(ctx.incoming->stats.loopDrops, 1);
 854                         NG_FREE_ITEM(item);
 855                         NG_FREE_M(ctx.m);
 856                         return (ELOOP);
 857                 }
 858         }
 859
 860         /*
 861          * If unicast and destination host known, deliver to host's link,
 862          * unless it is the same link as the packet came in on.
 863          */
 864         if (!ctx.manycast) {
 865                 /* Determine packet destination link */
 866                 if ((host = ng_bridge_get(priv, eh->ether_dhost)) != NULL) {
 867                         link_p destLink = host->link;
 868
 869                         /* If destination same as incoming link, do nothing */
 870                         if (destLink == ctx.incoming) {
 871                                 NG_FREE_ITEM(item);
 872                                 NG_FREE_M(ctx.m);
 873                                 return (0);
 874                         }
 875
 876                         /* Deliver packet out the destination link */
 877                         return (ng_bridge_send_data(destLink, ctx.manycast, ctx.m, item));
 878                 }
 879
 880                 /* Destination host is not known */
 881                 counter_u64_add(ctx.incoming->stats.recvUnknown, 1);
 882         }
 883
 884         /* Distribute unknown, multicast, broadcast pkts to all other links */
 885         NG_NODE_FOREACH_HOOK(node, ng_bridge_send_ctx, &ctx);
 886
 887         /* Finally send out on the first link found */
 888         if (ctx.foundFirst != NULL) {
 889                 int error = ng_bridge_send_data(ctx.foundFirst, ctx.manycast, ctx.m, item);
 890                 if (error)
 891                         ctx.error = error;
 892         } else {                       /* nothing to send at all */
 893                 NG_FREE_ITEM(item);
 894                 NG_FREE_M(ctx.m);
 895         }
 896
 897         return (ctx.error);
 898 }
 899
 900 /*
 901  * Shutdown node
 902  */
 903 static int
 904 ng_bridge_shutdown(node_p node)
 905 {
 906         const priv_p priv = NG_NODE_PRIVATE(node);
 907
 908         /*
 909          * Shut down everything including the timer.  Even if the
 910          * callout has already been dequeued and is about to be
 911          * run, ng_bridge_timeout() won't be fired as the node
 912          * is already marked NGF_INVALID, so we're safe to free
 913          * the node now.
 914          */
 915         KASSERT(priv->numLinks == 0 && priv->numHosts == 0,
 916             ("%s: numLinks=%d numHosts=%d",
 917             __func__, priv->numLinks, priv->numHosts));
 918         ng_uncallout(&priv->timer, node);
 919         NG_NODE_SET_PRIVATE(node, NULL);
 920         NG_NODE_UNREF(node);
 921         free(priv->tab, M_NETGRAPH_BRIDGE);
 922         free(priv, M_NETGRAPH_BRIDGE);
 923         return (0);
 924 }
 925
 926 /*
 927  * Hook disconnection.
 928  */
 929 static int
 930 ng_bridge_disconnect(hook_p hook)
 931 {
 932         const priv_p priv = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
 933         link_p link = NG_HOOK_PRIVATE(hook);
 934
 935         /* Remove all hosts associated with this link */
 936         ng_bridge_remove_hosts(priv, link);
 937
 938         /* Free associated link information */
 939         ng_bridge_free_link(link);
 940         priv->numLinks--;
 941
 942         /* If no more hooks, go away */
 943         if ((NG_NODE_NUMHOOKS(NG_HOOK_NODE(hook)) == 0)
 944             && (NG_NODE_IS_VALID(NG_HOOK_NODE(hook)))
 945             && !priv->persistent) {
 946                 ng_rmnode_self(NG_HOOK_NODE(hook));
 947         }
 948         return (0);
 949 }
 950
 951 /******************************************************************
 952                     HASH TABLE FUNCTIONS
 953 ******************************************************************/
 954
 955 /*
 956  * Hash algorithm
 957  */
 958 #define HASH(addr,mask)         ( (((const u_int16_t *)(addr))[0]       \
 959                                  ^ ((const u_int16_t *)(addr))[1]       \
 960                                  ^ ((const u_int16_t *)(addr))[2]) & (mask) )
 961
 962 /*
 963  * Find a host entry in the table.
 964  */
 965 static struct ng_bridge_host *
 966 ng_bridge_get(priv_cp priv, const u_char *addr)
 967 {
 968         const int bucket = HASH(addr, priv->hashMask);
 969         struct ng_bridge_host *host;
 970
 971         SLIST_FOREACH(host, &priv->tab[bucket], next) {
 972                 if (ETHER_EQUAL(host->addr, addr))
 973                         return (host);
 974         }
 975         return (NULL);
 976 }
 977
 978 /*
 979  * Add a host entry to the table. If it already exists, move it
 980  * to the new link. Returns 0 on success.
 981  */
 982 static int
 983 ng_bridge_put(priv_p priv, const u_char *addr, link_p link)
 984 {
 985         const int bucket = HASH(addr, priv->hashMask);
 986         struct ng_bridge_host *host;
 987
 988         if ((host = ng_bridge_get(priv, addr)) != NULL) {
 989                 /* Host already on the correct link? */
 990                 if (host->link == link)
 991                         return 0;
 992
 993                 /* Move old host over to new link */
 994                 if (host->age >= priv->conf.minStableAge) {
 995                         host->link = link;
 996                         host->age = 0;
 997                         return (0);
 998                 }
 999                 /*
1000                  * If the host was recently moved to the old link and
1001                  * it's now jumping to a new link, declare a loopback
1002                  * condition.
1003                  */
1004                 if (priv->conf.debugLevel >= 2)
1005                     log(LOG_WARNING, "ng_bridge: %s:"
1006                         " loopback detected on %s\n",
1007                         ng_bridge_nodename(priv->node),
1008                         NG_HOOK_NAME(link->hook));
1009
1010                 /* Mark link as linka non grata */
1011                 link->loopCount = priv->conf.loopTimeout;
1012                 link->stats.loopDetects++;
1013
1014                 /* Forget all hosts on this link */
1015                 ng_bridge_remove_hosts(priv, link);
1016                 return (ELOOP);
1017         }
1018
1019         /* Allocate and initialize new hashtable entry */
1020         host = malloc(sizeof(*host), M_NETGRAPH_BRIDGE, M_NOWAIT);
1021         if (host == NULL)
1022                 return (ENOMEM);
1023         bcopy(addr, host->addr, ETHER_ADDR_LEN);
1024         host->link = link;
1025         host->staleness = 0;
1026         host->age = 0;
1027
1028         /* Add new element to hash bucket */
1029         SLIST_INSERT_HEAD(&priv->tab[bucket], host, next);
1030         priv->numHosts++;
1031
1032         /* Resize table if necessary */
1033         ng_bridge_rehash(priv);
1034         return (0);
1035 }
1036
1037 /*
1038  * Resize the hash table. We try to maintain the number of buckets
1039  * such that the load factor is in the range 0.25 to 1.0.
1040  *
1041  * If we can't get the new memory then we silently fail. This is OK
1042  * because things will still work and we'll try again soon anyway.
1043  */
1044 static void
1045 ng_bridge_rehash(priv_p priv)
1046 {
1047         struct ng_bridge_bucket *newTab;
1048         int oldBucket, newBucket;
1049         int newNumBuckets;
1050         u_int newMask;
1051
1052         /* Is table too full or too empty? */
1053         if (priv->numHosts > priv->numBuckets
1054             && (priv->numBuckets << 1) <= MAX_BUCKETS)
1055                 newNumBuckets = priv->numBuckets << 1;
1056         else if (priv->numHosts < (priv->numBuckets >> 2)
1057             && (priv->numBuckets >> 2) >= MIN_BUCKETS)
1058                 newNumBuckets = priv->numBuckets >> 2;
1059         else
1060                 return;
1061         newMask = newNumBuckets - 1;
1062
1063         /* Allocate and initialize new table */
1064         newTab = malloc(newNumBuckets * sizeof(*newTab),
1065             M_NETGRAPH_BRIDGE, M_NOWAIT | M_ZERO);
1066         if (newTab == NULL)
1067                 return;
1068
1069         /* Move all entries from old table to new table */
1070         for (oldBucket = 0; oldBucket < priv->numBuckets; oldBucket++) {
1071                 struct ng_bridge_bucket *const oldList = &priv->tab[oldBucket];
1072
1073                 while (!SLIST_EMPTY(oldList)) {
1074                         struct ng_bridge_host *const host
1075                             = SLIST_FIRST(oldList);
1076
1077                         SLIST_REMOVE_HEAD(oldList, next);
1078                         newBucket = HASH(host->addr, newMask);
1079                         SLIST_INSERT_HEAD(&newTab[newBucket], host, next);
1080                 }
1081         }
1082
1083         /* Replace old table with new one */
1084         if (priv->conf.debugLevel >= 3) {
1085                 log(LOG_INFO, "ng_bridge: %s: table size %d -> %d\n",
1086                     ng_bridge_nodename(priv->node),
1087                     priv->numBuckets, newNumBuckets);
1088         }
1089         free(priv->tab, M_NETGRAPH_BRIDGE);
1090         priv->numBuckets = newNumBuckets;
1091         priv->hashMask = newMask;
1092         priv->tab = newTab;
1093         return;
1094 }
1095
1096 /******************************************************************
1097                     MISC FUNCTIONS
1098 ******************************************************************/
1099
1100 /*
1101  * Remove all hosts associated with a specific link from the hashtable.
1102  * If linkNum == -1, then remove all hosts in the table.
1103  */
1104 static void
1105 ng_bridge_remove_hosts(priv_p priv, link_p link)
1106 {
1107         int bucket;
1108
1109         for (bucket = 0; bucket < priv->numBuckets; bucket++) {
1110                 struct ng_bridge_host **hptr = &SLIST_FIRST(&priv->tab[bucket]);
1111
1112                 while (*hptr != NULL) {
1113                         struct ng_bridge_host *const host = *hptr;
1114
1115                         if (link == NULL || host->link == link) {
1116                                 *hptr = SLIST_NEXT(host, next);
1117                                 free(host, M_NETGRAPH_BRIDGE);
1118                                 priv->numHosts--;
1119                         } else
1120                                 hptr = &SLIST_NEXT(host, next);
1121                 }
1122         }
1123 }
1124
1125 /*
1126  * Handle our once-per-second timeout event. We do two things:
1127  * we decrement link->loopCount for those links being muted due to
1128  * a detected loopback condition, and we remove any hosts from
1129  * the hashtable whom we haven't heard from in a long while.
1130  */
1131 static int
1132 ng_bridge_unmute(hook_p hook, void *arg)
1133 {
1134         link_p link = NG_HOOK_PRIVATE(hook);
1135         node_p node = NG_HOOK_NODE(hook);
1136         priv_p priv = NG_NODE_PRIVATE(node);
1137         int *counter = arg;
1138
1139         if (link->loopCount != 0) {
1140                 link->loopCount--;
1141                 if (link->loopCount == 0 && priv->conf.debugLevel >= 2) {
1142                         log(LOG_INFO, "ng_bridge: %s:"
1143                             " restoring looped back %s\n",
1144                             ng_bridge_nodename(node), NG_HOOK_NAME(hook));
1145                 }
1146         }
1147         (*counter)++;
1148         return (1);
1149 }
1150
1151 static void
1152 ng_bridge_timeout(node_p node, hook_p hook, void *arg1, int arg2)
1153 {
1154         const priv_p priv = NG_NODE_PRIVATE(node);
1155         int bucket;
1156         int counter = 0;
1157
1158         /* Update host time counters and remove stale entries */
1159         for (bucket = 0; bucket < priv->numBuckets; bucket++) {
1160                 struct ng_bridge_host **hptr = &SLIST_FIRST(&priv->tab[bucket]);
1161
1162                 while (*hptr != NULL) {
1163                         struct ng_bridge_host *const host = *hptr;
1164
1165                         /* Remove hosts we haven't heard from in a while */
1166                         if (++host->staleness >= priv->conf.maxStaleness) {
1167                                 *hptr = SLIST_NEXT(host, next);
1168                                 free(host, M_NETGRAPH_BRIDGE);
1169                                 priv->numHosts--;
1170                         } else {
1171                                 if (host->age < 0xffff)
1172                                         host->age++;
1173                                 hptr = &SLIST_NEXT(host, next);
1174                                 counter++;
1175                         }
1176                 }
1177         }
1178         KASSERT(priv->numHosts == counter,
1179             ("%s: hosts: %d != %d", __func__, priv->numHosts, counter));
1180
1181         /* Decrease table size if necessary */
1182         ng_bridge_rehash(priv);
1183
1184         /* Decrease loop counter on muted looped back links */
1185         counter = 0;
1186         NG_NODE_FOREACH_HOOK(node, ng_bridge_unmute, &counter);
1187         KASSERT(priv->numLinks == counter,
1188             ("%s: links: %d != %d", __func__, priv->numLinks, counter));
1189
1190         /* Register a new timeout, keeping the existing node reference */
1191         ng_callout(&priv->timer, node, NULL, hz, ng_bridge_timeout, NULL, 0);
1192 }
1193
1194 /*
1195  * Return node's "name", even if it doesn't have one.
1196  */
1197 static const char *
1198 ng_bridge_nodename(node_cp node)
1199 {
1200         static char name[NG_NODESIZ];
1201
1202         if (NG_NODE_HAS_NAME(node))
1203                 snprintf(name, sizeof(name), "%s", NG_NODE_NAME(node));
1204         else
1205                 snprintf(name, sizeof(name), "[%x]", ng_node2ID(node));
1206         return name;
1207 }