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