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 #if 0   /* not used yet */
  78 #include <netinet/ip_fw.h>
  79 #endif
  80 #include <netgraph/ng_message.h>
  81 #include <netgraph/netgraph.h>
  82 #include <netgraph/ng_parse.h>
  83 #include <netgraph/ng_bridge.h>
  84
  85 #ifdef NG_SEPARATE_MALLOC
  86 static MALLOC_DEFINE(M_NETGRAPH_BRIDGE, "netgraph_bridge",
  87     "netgraph bridge node");
  88 #else
  89 #define M_NETGRAPH_BRIDGE M_NETGRAPH
  90 #endif
  91
  92 /* Counter based stats */
  93 struct ng_bridge_link_kernel_stats {
  94         counter_u64_t   recvOctets;     /* total octets rec'd on link */
  95         counter_u64_t   recvPackets;    /* total pkts rec'd on link */
  96         counter_u64_t   recvMulticasts; /* multicast pkts rec'd on link */
  97         counter_u64_t   recvBroadcasts; /* broadcast pkts rec'd on link */
  98         counter_u64_t   recvUnknown;    /* pkts rec'd with unknown dest addr */
  99         counter_u64_t   recvRunts;      /* pkts rec'd less than 14 bytes */
 100         counter_u64_t   recvInvalid;    /* pkts rec'd with bogus source addr */
 101         counter_u64_t   xmitOctets;     /* total octets xmit'd on link */
 102         counter_u64_t   xmitPackets;    /* total pkts xmit'd on link */
 103         counter_u64_t   xmitMulticasts; /* multicast pkts xmit'd on link */
 104         counter_u64_t   xmitBroadcasts; /* broadcast pkts xmit'd on link */
 105         counter_u64_t   loopDrops;      /* pkts dropped due to loopback */
 106         u_int64_t       loopDetects;    /* number of loop detections */
 107         counter_u64_t   memoryFailures; /* times couldn't get mem or mbuf */
 108 };
 109
 110 /* Per-link private data */
 111 struct ng_bridge_link {
 112         hook_p                          hook;           /* netgraph hook */
 113         u_int16_t                       loopCount;      /* loop ignore timer */
 114         unsigned int                    learnMac : 1,   /* autolearn macs */
 115                                         sendUnknown : 1;/* send unknown macs out */
 116         struct ng_bridge_link_kernel_stats stats;       /* link stats */
 117 };
 118 typedef struct ng_bridge_link const *link_cp;   /* read only access */
 119
 120 /* Per-node private data */
 121 struct ng_bridge_private {
 122         struct ng_bridge_bucket *tab;           /* hash table bucket array */
 123         struct ng_bridge_config conf;           /* node configuration */
 124         node_p                  node;           /* netgraph node */
 125         u_int                   numHosts;       /* num entries in table */
 126         u_int                   numBuckets;     /* num buckets in table */
 127         u_int                   hashMask;       /* numBuckets - 1 */
 128         int                     numLinks;       /* num connected links */
 129         unsigned int            persistent : 1, /* can exist w/o hooks */
 130                                 sendUnknown : 1;/* links receive unknowns by default */
 131         struct callout          timer;          /* one second periodic timer */
 132 };
 133 typedef struct ng_bridge_private *priv_p;
 134 typedef struct ng_bridge_private const *priv_cp;        /* read only access */
 135
 136 /* Information about a host, stored in a hash table entry */
 137 struct ng_bridge_host {
 138         u_char          addr[6];        /* ethernet address */
 139         link_p          link;           /* link where addr can be found */
 140         u_int16_t       age;            /* seconds ago entry was created */
 141         u_int16_t       staleness;      /* seconds ago host last heard from */
 142         SLIST_ENTRY(ng_bridge_host)     next;   /* next entry in bucket */
 143 };
 144
 145 /* Hash table bucket declaration */
 146 SLIST_HEAD(ng_bridge_bucket, ng_bridge_host);
 147
 148 /* Netgraph node methods */
 149 static ng_constructor_t ng_bridge_constructor;
 150 static ng_rcvmsg_t      ng_bridge_rcvmsg;
 151 static ng_shutdown_t    ng_bridge_shutdown;
 152 static ng_newhook_t     ng_bridge_newhook;
 153 static ng_rcvdata_t     ng_bridge_rcvdata;
 154 static ng_disconnect_t  ng_bridge_disconnect;
 155
 156 /* Other internal functions */
 157 static void     ng_bridge_free_link(link_p link);
 158 static struct   ng_bridge_host *ng_bridge_get(priv_cp priv, const u_char *addr);
 159 static int      ng_bridge_put(priv_p priv, const u_char *addr, link_p link);
 160 static void     ng_bridge_rehash(priv_p priv);
 161 static void     ng_bridge_remove_hosts(priv_p priv, link_p link);
 162 static void     ng_bridge_timeout(node_p node, hook_p hook, void *arg1, int arg2);
 163 static const    char *ng_bridge_nodename(node_cp node);
 164
 165 /* Ethernet broadcast */
 166 static const u_char ng_bridge_bcast_addr[ETHER_ADDR_LEN] =
 167     { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
 168
 169 /* Compare Ethernet addresses using 32 and 16 bit words instead of bytewise */
 170 #define ETHER_EQUAL(a,b)        (((const u_int32_t *)(a))[0] \
 171                                         == ((const u_int32_t *)(b))[0] \
 172                                     && ((const u_int16_t *)(a))[2] \
 173                                         == ((const u_int16_t *)(b))[2])
 174
 175 /* Minimum and maximum number of hash buckets. Must be a power of two. */
 176 #define MIN_BUCKETS             (1 << 5)        /* 32 */
 177 #define MAX_BUCKETS             (1 << 14)       /* 16384 */
 178
 179 /* Configuration default values */
 180 #define DEFAULT_LOOP_TIMEOUT    60
 181 #define DEFAULT_MAX_STALENESS   (15 * 60)       /* same as ARP timeout */
 182 #define DEFAULT_MIN_STABLE_AGE  1
 183
 184 /******************************************************************
 185                     NETGRAPH PARSE TYPES
 186 ******************************************************************/
 187
 188 /*
 189  * How to determine the length of the table returned by NGM_BRIDGE_GET_TABLE
 190  */
 191 static int
 192 ng_bridge_getTableLength(const struct ng_parse_type *type,
 193         const u_char *start, const u_char *buf)
 194 {
 195         const struct ng_bridge_host_ary *const hary
 196             = (const struct ng_bridge_host_ary *)(buf - sizeof(u_int32_t));
 197
 198         return hary->numHosts;
 199 }
 200
 201 /* Parse type for struct ng_bridge_host_ary */
 202 static const struct ng_parse_struct_field ng_bridge_host_type_fields[]
 203         = NG_BRIDGE_HOST_TYPE_INFO(&ng_parse_enaddr_type);
 204 static const struct ng_parse_type ng_bridge_host_type = {
 205         &ng_parse_struct_type,
 206         &ng_bridge_host_type_fields
 207 };
 208 static const struct ng_parse_array_info ng_bridge_hary_type_info = {
 209         &ng_bridge_host_type,
 210         ng_bridge_getTableLength
 211 };
 212 static const struct ng_parse_type ng_bridge_hary_type = {
 213         &ng_parse_array_type,
 214         &ng_bridge_hary_type_info
 215 };
 216 static const struct ng_parse_struct_field ng_bridge_host_ary_type_fields[]
 217         = NG_BRIDGE_HOST_ARY_TYPE_INFO(&ng_bridge_hary_type);
 218 static const struct ng_parse_type ng_bridge_host_ary_type = {
 219         &ng_parse_struct_type,
 220         &ng_bridge_host_ary_type_fields
 221 };
 222
 223 /* Parse type for struct ng_bridge_config */
 224 static const struct ng_parse_struct_field ng_bridge_config_type_fields[]
 225         = NG_BRIDGE_CONFIG_TYPE_INFO;
 226 static const struct ng_parse_type ng_bridge_config_type = {
 227         &ng_parse_struct_type,
 228         &ng_bridge_config_type_fields
 229 };
 230
 231 /* Parse type for struct ng_bridge_link_stat */
 232 static const struct ng_parse_struct_field ng_bridge_stats_type_fields[]
 233         = NG_BRIDGE_STATS_TYPE_INFO;
 234 static const struct ng_parse_type ng_bridge_stats_type = {
 235         &ng_parse_struct_type,
 236         &ng_bridge_stats_type_fields
 237 };
 238 /* Parse type for struct ng_bridge_move_host */
 239 static const struct ng_parse_struct_field ng_bridge_move_host_type_fields[]
 240         = NG_BRIDGE_MOVE_HOST_TYPE_INFO(&ng_parse_enaddr_type);
 241 static const struct ng_parse_type ng_bridge_move_host_type = {
 242         &ng_parse_struct_type,
 243         &ng_bridge_move_host_type_fields
 244 };
 245
 246 /* List of commands and how to convert arguments to/from ASCII */
 247 static const struct ng_cmdlist ng_bridge_cmdlist[] = {
 248         {
 249           NGM_BRIDGE_COOKIE,
 250           NGM_BRIDGE_SET_CONFIG,
 251           "setconfig",
 252           &ng_bridge_config_type,
 253           NULL
 254         },
 255         {
 256           NGM_BRIDGE_COOKIE,
 257           NGM_BRIDGE_GET_CONFIG,
 258           "getconfig",
 259           NULL,
 260           &ng_bridge_config_type
 261         },
 262         {
 263           NGM_BRIDGE_COOKIE,
 264           NGM_BRIDGE_RESET,
 265           "reset",
 266           NULL,
 267           NULL
 268         },
 269         {
 270           NGM_BRIDGE_COOKIE,
 271           NGM_BRIDGE_GET_STATS,
 272           "getstats",
 273           &ng_parse_uint32_type,
 274           &ng_bridge_stats_type
 275         },
 276         {
 277           NGM_BRIDGE_COOKIE,
 278           NGM_BRIDGE_CLR_STATS,
 279           "clrstats",
 280           &ng_parse_uint32_type,
 281           NULL
 282         },
 283         {
 284           NGM_BRIDGE_COOKIE,
 285           NGM_BRIDGE_GETCLR_STATS,
 286           "getclrstats",
 287           &ng_parse_uint32_type,
 288           &ng_bridge_stats_type
 289         },
 290         {
 291           NGM_BRIDGE_COOKIE,
 292           NGM_BRIDGE_GET_TABLE,
 293           "gettable",
 294           NULL,
 295           &ng_bridge_host_ary_type
 296         },
 297         {
 298           NGM_BRIDGE_COOKIE,
 299           NGM_BRIDGE_SET_PERSISTENT,
 300           "setpersistent",
 301           NULL,
 302           NULL
 303         },
 304         {
 305           NGM_BRIDGE_COOKIE,
 306           NGM_BRIDGE_MOVE_HOST,
 307           "movehost",
 308           &ng_bridge_move_host_type,
 309           NULL
 310         },
 311         { 0 }
 312 };
 313
 314 /* Node type descriptor */
 315 static struct ng_type ng_bridge_typestruct = {
 316         .version =      NG_ABI_VERSION,
 317         .name =         NG_BRIDGE_NODE_TYPE,
 318         .constructor =  ng_bridge_constructor,
 319         .rcvmsg =       ng_bridge_rcvmsg,
 320         .shutdown =     ng_bridge_shutdown,
 321         .newhook =      ng_bridge_newhook,
 322         .rcvdata =      ng_bridge_rcvdata,
 323         .disconnect =   ng_bridge_disconnect,
 324         .cmdlist =      ng_bridge_cmdlist,
 325 };
 326 NETGRAPH_INIT(bridge, &ng_bridge_typestruct);
 327
 328 /******************************************************************
 329                     NETGRAPH NODE METHODS
 330 ******************************************************************/
 331
 332 /*
 333  * Node constructor
 334  */
 335 static int
 336 ng_bridge_constructor(node_p node)
 337 {
 338         priv_p priv;
 339
 340         /* Allocate and initialize private info */
 341         priv = malloc(sizeof(*priv), M_NETGRAPH_BRIDGE, M_WAITOK | M_ZERO);
 342         ng_callout_init(&priv->timer);
 343
 344         /* Allocate and initialize hash table, etc. */
 345         priv->tab = malloc(MIN_BUCKETS * sizeof(*priv->tab),
 346             M_NETGRAPH_BRIDGE, M_WAITOK | M_ZERO);
 347         priv->numBuckets = MIN_BUCKETS;
 348         priv->hashMask = MIN_BUCKETS - 1;
 349         priv->conf.debugLevel = 1;
 350         priv->conf.loopTimeout = DEFAULT_LOOP_TIMEOUT;
 351         priv->conf.maxStaleness = DEFAULT_MAX_STALENESS;
 352         priv->conf.minStableAge = DEFAULT_MIN_STABLE_AGE;
 353         priv->sendUnknown = 1;         /* classic bridge */
 354
 355         NG_NODE_SET_PRIVATE(node, priv);
 356         priv->node = node;
 357
 358         /* Start timer; timer is always running while node is alive */
 359         ng_callout(&priv->timer, node, NULL, hz, ng_bridge_timeout, NULL, 0);
 360
 361         /* Done */
 362         return (0);
 363 }
 364
 365 /*
 366  * Method for attaching a new hook
 367  */
 368 static  int
 369 ng_bridge_newhook(node_p node, hook_p hook, const char *name)
 370 {
 371         const priv_p priv = NG_NODE_PRIVATE(node);
 372         char linkName[NG_HOOKSIZ];
 373         u_int32_t linkNum;
 374         link_p link;
 375         const char *prefix = NG_BRIDGE_HOOK_LINK_PREFIX;
 376         bool isUplink;
 377
 378         /* Check for a link hook */
 379         if (strlen(name) <= strlen(prefix))
 380                 return (EINVAL);       /* Unknown hook name */
 381
 382         isUplink = (name[0] == 'u');
 383         if (isUplink)
 384                 prefix = NG_BRIDGE_HOOK_UPLINK_PREFIX;
 385
 386         /* primitive parsing */
 387         linkNum = strtoul(name + strlen(prefix), NULL, 10);
 388         /* validation by comparing against the reconstucted name  */
 389         snprintf(linkName, sizeof(linkName), "%s%u", prefix, linkNum);
 390         if (strcmp(linkName, name) != 0)
 391                 return (EINVAL);
 392
 393         if (linkNum == 0 && isUplink)
 394                 return (EINVAL);
 395
 396         if(NG_PEER_NODE(hook) == node)
 397                 return (ELOOP);
 398
 399         link = malloc(sizeof(*link), M_NETGRAPH_BRIDGE, M_NOWAIT | M_ZERO);
 400         if (link == NULL)
 401                 return (ENOMEM);
 402
 403 #define NG_BRIDGE_COUNTER_ALLOC(f) do {                 \
 404         link->stats.f = counter_u64_alloc(M_NOWAIT);    \
 405         if (link->stats.f == NULL)                      \
 406                 goto nomem;                             \
 407 } while (0)
 408         NG_BRIDGE_COUNTER_ALLOC(recvOctets);
 409         NG_BRIDGE_COUNTER_ALLOC(recvPackets);
 410         NG_BRIDGE_COUNTER_ALLOC(recvMulticasts);
 411         NG_BRIDGE_COUNTER_ALLOC(recvBroadcasts);
 412         NG_BRIDGE_COUNTER_ALLOC(recvUnknown);
 413         NG_BRIDGE_COUNTER_ALLOC(recvRunts);
 414         NG_BRIDGE_COUNTER_ALLOC(recvInvalid);
 415         NG_BRIDGE_COUNTER_ALLOC(xmitOctets);
 416         NG_BRIDGE_COUNTER_ALLOC(xmitPackets);
 417         NG_BRIDGE_COUNTER_ALLOC(xmitMulticasts);
 418         NG_BRIDGE_COUNTER_ALLOC(xmitBroadcasts);
 419         NG_BRIDGE_COUNTER_ALLOC(loopDrops);
 420         NG_BRIDGE_COUNTER_ALLOC(memoryFailures);
 421 #undef NG_BRIDGE_COUNTER_ALLOC
 422
 423         link->hook = hook;
 424         if (isUplink) {
 425                 link->learnMac = 0;
 426                 link->sendUnknown = 1;
 427                 if (priv->numLinks == 0)        /* if the first link is an uplink */
 428                         priv->sendUnknown = 0;  /* switch to restrictive mode */
 429         } else {
 430                 link->learnMac = 1;
 431                 link->sendUnknown = priv->sendUnknown;
 432         }
 433
 434         NG_HOOK_SET_PRIVATE(hook, link);
 435         priv->numLinks++;
 436         return (0);
 437
 438 nomem:
 439         ng_bridge_free_link(link);
 440         return (ENOMEM);
 441 }
 442
 443 /*
 444  * Receive a control message
 445  */
 446 static void
 447 ng_bridge_clear_link_stats(struct ng_bridge_link_kernel_stats *p)
 448 {
 449         counter_u64_zero(p->recvOctets);
 450         counter_u64_zero(p->recvPackets);
 451         counter_u64_zero(p->recvMulticasts);
 452         counter_u64_zero(p->recvBroadcasts);
 453         counter_u64_zero(p->recvUnknown);
 454         counter_u64_zero(p->recvRunts);
 455         counter_u64_zero(p->recvInvalid);
 456         counter_u64_zero(p->xmitOctets);
 457         counter_u64_zero(p->xmitPackets);
 458         counter_u64_zero(p->xmitMulticasts);
 459         counter_u64_zero(p->xmitBroadcasts);
 460         counter_u64_zero(p->loopDrops);
 461         p->loopDetects = 0;
 462         counter_u64_zero(p->memoryFailures);
 463 }
 464
 465 static void
 466 ng_bridge_free_link(link_p link)
 467 {
 468         counter_u64_free(link->stats.recvOctets);
 469         counter_u64_free(link->stats.recvPackets);
 470         counter_u64_free(link->stats.recvMulticasts);
 471         counter_u64_free(link->stats.recvBroadcasts);
 472         counter_u64_free(link->stats.recvUnknown);
 473         counter_u64_free(link->stats.recvRunts);
 474         counter_u64_free(link->stats.recvInvalid);
 475         counter_u64_free(link->stats.xmitOctets);
 476         counter_u64_free(link->stats.xmitPackets);
 477         counter_u64_free(link->stats.xmitMulticasts);
 478         counter_u64_free(link->stats.xmitBroadcasts);
 479         counter_u64_free(link->stats.loopDrops);
 480         counter_u64_free(link->stats.memoryFailures);
 481         free(link, M_NETGRAPH_BRIDGE);
 482 }
 483
 484 static int
 485 ng_bridge_reset_link(hook_p hook, void *arg __unused)
 486 {
 487         link_p priv = NG_HOOK_PRIVATE(hook);
 488
 489         priv->loopCount = 0;
 490         ng_bridge_clear_link_stats(&priv->stats);
 491         return (1);
 492 }
 493
 494 static int
 495 ng_bridge_rcvmsg(node_p node, item_p item, hook_p lasthook)
 496 {
 497         const priv_p priv = NG_NODE_PRIVATE(node);
 498         struct ng_mesg *resp = NULL;
 499         int error = 0;
 500         struct ng_mesg *msg;
 501
 502         NGI_GET_MSG(item, msg);
 503         switch (msg->header.typecookie) {
 504         case NGM_BRIDGE_COOKIE:
 505                 switch (msg->header.cmd) {
 506                 case NGM_BRIDGE_GET_CONFIG:
 507                     {
 508                         struct ng_bridge_config *conf;
 509
 510                         NG_MKRESPONSE(resp, msg,
 511                             sizeof(struct ng_bridge_config), M_NOWAIT);
 512                         if (resp == NULL) {
 513                                 error = ENOMEM;
 514                                 break;
 515                         }
 516                         conf = (struct ng_bridge_config *)resp->data;
 517                         *conf = priv->conf;     /* no sanity checking needed */
 518                         break;
 519                     }
 520                 case NGM_BRIDGE_SET_CONFIG:
 521                     {
 522                         struct ng_bridge_config *conf;
 523
 524                         if (msg->header.arglen
 525                             != sizeof(struct ng_bridge_config)) {
 526                                 error = EINVAL;
 527                                 break;
 528                         }
 529                         conf = (struct ng_bridge_config *)msg->data;
 530                         priv->conf = *conf;
 531                         break;
 532                     }
 533                 case NGM_BRIDGE_RESET:
 534                     {
 535                         /* Flush all entries in the hash table */
 536                         ng_bridge_remove_hosts(priv, NULL);
 537
 538                         /* Reset all loop detection counters and stats */
 539                         NG_NODE_FOREACH_HOOK(node, ng_bridge_reset_link, NULL);
 540                         break;
 541                     }
 542                 case NGM_BRIDGE_GET_STATS:
 543                 case NGM_BRIDGE_CLR_STATS:
 544                 case NGM_BRIDGE_GETCLR_STATS:
 545                     {
 546                         hook_p hook;
 547                         link_p link;
 548                         char linkName[NG_HOOKSIZ];
 549                         int linkNum;
 550
 551                         /* Get link number */
 552                         if (msg->header.arglen != sizeof(u_int32_t)) {
 553                                 error = EINVAL;
 554                                 break;
 555                         }
 556                         linkNum = *((int32_t *)msg->data);
 557                         if (linkNum < 0)
 558                                 snprintf(linkName, sizeof(linkName),
 559                                     "%s%u", NG_BRIDGE_HOOK_UPLINK_PREFIX, -linkNum);
 560                         else
 561                                 snprintf(linkName, sizeof(linkName),
 562                                     "%s%u", NG_BRIDGE_HOOK_LINK_PREFIX, linkNum);
 563
 564                         if ((hook = ng_findhook(node, linkName)) == NULL) {
 565                                 error = ENOTCONN;
 566                                 break;
 567                         }
 568                         link = NG_HOOK_PRIVATE(hook);
 569
 570                         /* Get/clear stats */
 571                         if (msg->header.cmd != NGM_BRIDGE_CLR_STATS) {
 572                                 struct ng_bridge_link_stats *rs;
 573
 574                                 NG_MKRESPONSE(resp, msg,
 575                                     sizeof(link->stats), M_NOWAIT);
 576                                 if (resp == NULL) {
 577                                         error = ENOMEM;
 578                                         break;
 579                                 }
 580                                 rs = (struct ng_bridge_link_stats *)resp->data;
 581 #define FETCH(x)        rs->x = counter_u64_fetch(link->stats.x)
 582                                 FETCH(recvOctets);
 583                                 FETCH(recvPackets);
 584                                 FETCH(recvMulticasts);
 585                                 FETCH(recvBroadcasts);
 586                                 FETCH(recvUnknown);
 587                                 FETCH(recvRunts);
 588                                 FETCH(recvInvalid);
 589                                 FETCH(xmitOctets);
 590                                 FETCH(xmitPackets);
 591                                 FETCH(xmitMulticasts);
 592                                 FETCH(xmitBroadcasts);
 593                                 FETCH(loopDrops);
 594                                 rs->loopDetects = link->stats.loopDetects;
 595                                 FETCH(memoryFailures);
 596 #undef FETCH
 597                         }
 598                         if (msg->header.cmd != NGM_BRIDGE_GET_STATS)
 599                                 ng_bridge_clear_link_stats(&link->stats);
 600                         break;
 601                     }
 602                 case NGM_BRIDGE_GET_TABLE:
 603                     {
 604                         struct ng_bridge_host_ary *ary;
 605                         struct ng_bridge_host *host;
 606                         int i = 0, bucket;
 607
 608                         NG_MKRESPONSE(resp, msg, sizeof(*ary)
 609                             + (priv->numHosts * sizeof(*ary->hosts)), M_NOWAIT);
 610                         if (resp == NULL) {
 611                                 error = ENOMEM;
 612                                 break;
 613                         }
 614                         ary = (struct ng_bridge_host_ary *)resp->data;
 615                         ary->numHosts = priv->numHosts;
 616                         for (bucket = 0; bucket < priv->numBuckets; bucket++) {
 617                                 SLIST_FOREACH(host, &priv->tab[bucket], next) {
 618                                         memcpy(ary->hosts[i].addr,
 619                                                host->addr,
 620                                                sizeof(ary->hosts[i].addr));
 621                                         ary->hosts[i].age       = host->age;
 622                                         ary->hosts[i].staleness = host->staleness;
 623                                         strncpy(ary->hosts[i].hook,
 624                                                 NG_HOOK_NAME(host->link->hook),
 625                                                 sizeof(ary->hosts[i].hook));
 626                                         i++;
 627                                 }
 628                         }
 629                         break;
 630                     }
 631                 case NGM_BRIDGE_SET_PERSISTENT:
 632                     {
 633                         priv->persistent = 1;
 634                         break;
 635                     }
 636                 case NGM_BRIDGE_MOVE_HOST:
 637                 {
 638                         struct ng_bridge_move_host *mh;
 639                         hook_p hook;
 640
 641                         if (msg->header.arglen < sizeof(*mh)) {
 642                                 error = EINVAL;
 643                                 break;
 644                         }
 645                         mh = (struct ng_bridge_move_host *)msg->data;
 646                         hook = (mh->hook[0] == 0)
 647                             ? lasthook
 648                             : ng_findhook(node, mh->hook);
 649                         if (hook == NULL) {
 650                                 error = ENOENT;
 651                                 break;
 652                         }
 653                         error = ng_bridge_put(priv, mh->addr, NG_HOOK_PRIVATE(hook));
 654                         break;
 655                 }
 656                 default:
 657                         error = EINVAL;
 658                         break;
 659                 }
 660                 break;
 661         default:
 662                 error = EINVAL;
 663                 break;
 664         }
 665
 666         /* Done */
 667         NG_RESPOND_MSG(error, node, item, resp);
 668         NG_FREE_MSG(msg);
 669         return (error);
 670 }
 671
 672 /*
 673  * Receive data on a hook
 674  */
 675 struct ng_bridge_send_ctx {
 676         link_p foundFirst, incoming;
 677         struct mbuf * m;
 678         int manycast, error;
 679 };
 680
 681 /*
 682  * Update stats and send out
 683  */
 684 static inline int
 685 ng_bridge_send_data(link_cp dst, int manycast, struct mbuf *m, item_p item) {
 686         int error = 0;
 687         size_t len = m->m_pkthdr.len;
 688
 689         if(item != NULL)
 690                 NG_FWD_NEW_DATA(error, item, dst->hook, m);
 691         else
 692                 NG_SEND_DATA_ONLY(error, dst->hook, m);
 693
 694         if (error) {
 695                 if (error == ENOMEM)
 696                         counter_u64_add(dst->stats.memoryFailures, 1);
 697                 /* The packet is still ours */
 698                 if (item != NULL)
 699                         NG_FREE_ITEM(item);
 700                 if (m != NULL)
 701                         NG_FREE_M(m);
 702                 return (error);
 703         }
 704
 705         counter_u64_add(dst->stats.xmitPackets, 1);
 706         counter_u64_add(dst->stats.xmitOctets, len);
 707         switch (manycast) {
 708         default:                       /* unknown unicast */
 709                 break;
 710         case 1:                        /* multicast */
 711                 counter_u64_add(dst->stats.xmitMulticasts, 1);
 712                 break;
 713         case 2:                        /* broadcast */
 714                 counter_u64_add(dst->stats.xmitBroadcasts, 1);
 715                 break;
 716         }
 717         return (0);
 718 }
 719
 720 /*
 721  * Loop body for sending to multiple destinations
 722  * return 0 to stop looping
 723  */
 724 static int
 725 ng_bridge_send_ctx(hook_p dst, void *arg)
 726 {
 727         struct ng_bridge_send_ctx *ctx = arg;
 728         link_p destLink = NG_HOOK_PRIVATE(dst);
 729         struct mbuf *m2 = NULL;
 730         int error = 0;
 731
 732         /* Skip incoming link */
 733         if (destLink == ctx->incoming) {
 734                 return (1);
 735         }
 736
 737         /* Skip sending unknowns to undesired links  */
 738         if (!ctx->manycast && !destLink->sendUnknown)
 739                 return (1);
 740
 741         if (ctx->foundFirst == NULL) {
 742                 /*
 743                  * This is the first usable link we have found.
 744                  * Reserve it for the originals.
 745                  * If we never find another we save a copy.
 746                  */
 747                 ctx->foundFirst = destLink;
 748                 return (1);
 749         }
 750
 751         /*
 752          * It's usable link but not the reserved (first) one.
 753          * Copy mbuf info for sending.
 754          */
 755         m2 = m_dup(ctx->m, M_NOWAIT);
 756         if (m2 == NULL) {
 757                 counter_u64_add(ctx->incoming->stats.memoryFailures, 1);
 758                 ctx->error = ENOBUFS;
 759                 return (0);            /* abort loop, do not try again and again */
 760         }
 761
 762         /* Send packet */
 763         error = ng_bridge_send_data(destLink, ctx->manycast, m2, NULL);
 764         if (error)
 765           ctx->error = error;
 766         return (1);
 767 }
 768
 769 static int
 770 ng_bridge_rcvdata(hook_p hook, item_p item)
 771 {
 772         const node_p node = NG_HOOK_NODE(hook);
 773         const priv_p priv = NG_NODE_PRIVATE(node);
 774         struct ng_bridge_host *host;
 775         struct ether_header *eh;
 776         struct ng_bridge_send_ctx ctx = { 0 };
 777
 778         NGI_GET_M(item, ctx.m);
 779
 780         ctx.incoming = NG_HOOK_PRIVATE(hook);
 781         /* Sanity check packet and pull up header */
 782         if (ctx.m->m_pkthdr.len < ETHER_HDR_LEN) {
 783                 counter_u64_add(ctx.incoming->stats.recvRunts, 1);
 784                 NG_FREE_ITEM(item);
 785                 NG_FREE_M(ctx.m);
 786                 return (EINVAL);
 787         }
 788         if (ctx.m->m_len < ETHER_HDR_LEN && !(ctx.m = m_pullup(ctx.m, ETHER_HDR_LEN))) {
 789                 counter_u64_add(ctx.incoming->stats.memoryFailures, 1);
 790                 NG_FREE_ITEM(item);
 791                 return (ENOBUFS);
 792         }
 793         eh = mtod(ctx.m, struct ether_header *);
 794         if ((eh->ether_shost[0] & 1) != 0) {
 795                 counter_u64_add(ctx.incoming->stats.recvInvalid, 1);
 796                 NG_FREE_ITEM(item);
 797                 NG_FREE_M(ctx.m);
 798                 return (EINVAL);
 799         }
 800
 801         /* Is link disabled due to a loopback condition? */
 802         if (ctx.incoming->loopCount != 0) {
 803                 counter_u64_add(ctx.incoming->stats.loopDrops, 1);
 804                 NG_FREE_ITEM(item);
 805                 NG_FREE_M(ctx.m);
 806                 return (ELOOP);
 807         }
 808
 809         /* Update stats */
 810         counter_u64_add(ctx.incoming->stats.recvPackets, 1);
 811         counter_u64_add(ctx.incoming->stats.recvOctets, ctx.m->m_pkthdr.len);
 812         if ((ctx.manycast = (eh->ether_dhost[0] & 1)) != 0) {
 813                 if (ETHER_EQUAL(eh->ether_dhost, ng_bridge_bcast_addr)) {
 814                         counter_u64_add(ctx.incoming->stats.recvBroadcasts, 1);
 815                         ctx.manycast = 2;
 816                 } else
 817                         counter_u64_add(ctx.incoming->stats.recvMulticasts, 1);
 818         }
 819
 820         /* Look up packet's source Ethernet address in hashtable */
 821         if ((host = ng_bridge_get(priv, eh->ether_shost)) != NULL)
 822                 /* Update time since last heard from this host.
 823                  * This is safe without locking, because it's
 824                  * the only operation during shared access.
 825                  */
 826                 if (__predict_false(host->staleness > 0))
 827                         host->staleness = 0;
 828
 829         if ((host == NULL && ctx.incoming->learnMac) ||
 830             (host != NULL && host->link != ctx.incoming)) {
 831                 struct ng_mesg *msg;
 832                 struct ng_bridge_move_host *mh;
 833                 int error = 0;
 834
 835                 NG_MKMESSAGE(msg, NGM_BRIDGE_COOKIE, NGM_BRIDGE_MOVE_HOST,
 836                     sizeof(*mh), M_NOWAIT);
 837                 if (msg == NULL) {
 838                         counter_u64_add(ctx.incoming->stats.memoryFailures, 1);
 839                         NG_FREE_ITEM(item);
 840                         NG_FREE_M(ctx.m);
 841                         return (ENOMEM);
 842                 }
 843                 mh = (struct ng_bridge_move_host *)msg->data;
 844                 strncpy(mh->hook, NG_HOOK_NAME(ctx.incoming->hook),
 845                     sizeof(mh->hook));
 846                 memcpy(mh->addr, eh->ether_shost, sizeof(mh->addr));
 847                 NG_SEND_MSG_ID(error, node, msg, NG_NODE_ID(node),
 848                     NG_NODE_ID(node));
 849                 if (error)
 850                         counter_u64_add(ctx.incoming->stats.memoryFailures, 1);
 851         }
 852
 853         if (host != NULL && host->link != ctx.incoming) {
 854                 if (host->age < priv->conf.minStableAge) {
 855                         /* Drop packet on instable links */
 856                         counter_u64_add(ctx.incoming->stats.loopDrops, 1);
 857                         NG_FREE_ITEM(item);
 858                         NG_FREE_M(ctx.m);
 859                         return (ELOOP);
 860                 }
 861         }
 862
 863         /* Run packet through ipfw processing, if enabled */
 864 #if 0
 865         if (priv->conf.ipfw[linkNum] && V_fw_enable && V_ip_fw_chk_ptr != NULL) {
 866                 /* XXX not implemented yet */
 867         }
 868 #endif
 869
 870         /*
 871          * If unicast and destination host known, deliver to host's link,
 872          * unless it is the same link as the packet came in on.
 873          */
 874         if (!ctx.manycast) {
 875                 /* Determine packet destination link */
 876                 if ((host = ng_bridge_get(priv, eh->ether_dhost)) != NULL) {
 877                         link_p destLink = host->link;
 878
 879                         /* If destination same as incoming link, do nothing */
 880                         if (destLink == ctx.incoming) {
 881                                 NG_FREE_ITEM(item);
 882                                 NG_FREE_M(ctx.m);
 883                                 return (0);
 884                         }
 885
 886                         /* Deliver packet out the destination link */
 887                         return (ng_bridge_send_data(destLink, ctx.manycast, ctx.m, item));
 888                 }
 889
 890                 /* Destination host is not known */
 891                 counter_u64_add(ctx.incoming->stats.recvUnknown, 1);
 892         }
 893
 894         /* Distribute unknown, multicast, broadcast pkts to all other links */
 895         NG_NODE_FOREACH_HOOK(node, ng_bridge_send_ctx, &ctx);
 896
 897         /* Finally send out on the first link found */
 898         if (ctx.foundFirst != NULL) {
 899                 int error = ng_bridge_send_data(ctx.foundFirst, ctx.manycast, ctx.m, item);
 900                 if (error)
 901                         ctx.error = error;
 902         } else {                       /* nothing to send at all */
 903                 NG_FREE_ITEM(item);
 904                 NG_FREE_M(ctx.m);
 905         }
 906
 907         return (ctx.error);
 908 }
 909
 910 /*
 911  * Shutdown node
 912  */
 913 static int
 914 ng_bridge_shutdown(node_p node)
 915 {
 916         const priv_p priv = NG_NODE_PRIVATE(node);
 917
 918         /*
 919          * Shut down everything including the timer.  Even if the
 920          * callout has already been dequeued and is about to be
 921          * run, ng_bridge_timeout() won't be fired as the node
 922          * is already marked NGF_INVALID, so we're safe to free
 923          * the node now.
 924          */
 925         KASSERT(priv->numLinks == 0 && priv->numHosts == 0,
 926             ("%s: numLinks=%d numHosts=%d",
 927             __func__, priv->numLinks, priv->numHosts));
 928         ng_uncallout(&priv->timer, node);
 929         NG_NODE_SET_PRIVATE(node, NULL);
 930         NG_NODE_UNREF(node);
 931         free(priv->tab, M_NETGRAPH_BRIDGE);
 932         free(priv, M_NETGRAPH_BRIDGE);
 933         return (0);
 934 }
 935
 936 /*
 937  * Hook disconnection.
 938  */
 939 static int
 940 ng_bridge_disconnect(hook_p hook)
 941 {
 942         const priv_p priv = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
 943         link_p link = NG_HOOK_PRIVATE(hook);
 944
 945         /* Remove all hosts associated with this link */
 946         ng_bridge_remove_hosts(priv, link);
 947
 948         /* Free associated link information */
 949         ng_bridge_free_link(link);
 950         priv->numLinks--;
 951
 952         /* If no more hooks, go away */
 953         if ((NG_NODE_NUMHOOKS(NG_HOOK_NODE(hook)) == 0)
 954             && (NG_NODE_IS_VALID(NG_HOOK_NODE(hook)))
 955             && !priv->persistent) {
 956                 ng_rmnode_self(NG_HOOK_NODE(hook));
 957         }
 958         return (0);
 959 }
 960
 961 /******************************************************************
 962                     HASH TABLE FUNCTIONS
 963 ******************************************************************/
 964
 965 /*
 966  * Hash algorithm
 967  */
 968 #define HASH(addr,mask)         ( (((const u_int16_t *)(addr))[0]       \
 969                                  ^ ((const u_int16_t *)(addr))[1]       \
 970                                  ^ ((const u_int16_t *)(addr))[2]) & (mask) )
 971
 972 /*
 973  * Find a host entry in the table.
 974  */
 975 static struct ng_bridge_host *
 976 ng_bridge_get(priv_cp priv, const u_char *addr)
 977 {
 978         const int bucket = HASH(addr, priv->hashMask);
 979         struct ng_bridge_host *host;
 980
 981         SLIST_FOREACH(host, &priv->tab[bucket], next) {
 982                 if (ETHER_EQUAL(host->addr, addr))
 983                         return (host);
 984         }
 985         return (NULL);
 986 }
 987
 988 /*
 989  * Add a host entry to the table. If it already exists, move it
 990  * to the new link. Returns 0 on success.
 991  */
 992 static int
 993 ng_bridge_put(priv_p priv, const u_char *addr, link_p link)
 994 {
 995         const int bucket = HASH(addr, priv->hashMask);
 996         struct ng_bridge_host *host;
 997
 998         if ((host = ng_bridge_get(priv, addr)) != NULL) {
 999                 /* Host already on the correct link? */
1000                 if (host->link == link)
1001                         return 0;
1002
1003                 /* Move old host over to new link */
1004                 if (host->age >= priv->conf.minStableAge) {
1005                         host->link = link;
1006                         host->age = 0;
1007                         return (0);
1008                 }
1009                 /*
1010                  * If the host was recently moved to the old link and
1011                  * it's now jumping to a new link, declare a loopback
1012                  * condition.
1013                  */
1014                 if (priv->conf.debugLevel >= 2)
1015                     log(LOG_WARNING, "ng_bridge: %s:"
1016                         " loopback detected on %s\n",
1017                         ng_bridge_nodename(priv->node),
1018                         NG_HOOK_NAME(link->hook));
1019
1020                 /* Mark link as linka non grata */
1021                 link->loopCount = priv->conf.loopTimeout;
1022                 link->stats.loopDetects++;
1023
1024                 /* Forget all hosts on this link */
1025                 ng_bridge_remove_hosts(priv, link);
1026                 return (ELOOP);
1027         }
1028
1029         /* Allocate and initialize new hashtable entry */
1030         host = malloc(sizeof(*host), M_NETGRAPH_BRIDGE, M_NOWAIT);
1031         if (host == NULL)
1032                 return (ENOMEM);
1033         bcopy(addr, host->addr, ETHER_ADDR_LEN);
1034         host->link = link;
1035         host->staleness = 0;
1036         host->age = 0;
1037
1038         /* Add new element to hash bucket */
1039         SLIST_INSERT_HEAD(&priv->tab[bucket], host, next);
1040         priv->numHosts++;
1041
1042         /* Resize table if necessary */
1043         ng_bridge_rehash(priv);
1044         return (0);
1045 }
1046
1047 /*
1048  * Resize the hash table. We try to maintain the number of buckets
1049  * such that the load factor is in the range 0.25 to 1.0.
1050  *
1051  * If we can't get the new memory then we silently fail. This is OK
1052  * because things will still work and we'll try again soon anyway.
1053  */
1054 static void
1055 ng_bridge_rehash(priv_p priv)
1056 {
1057         struct ng_bridge_bucket *newTab;
1058         int oldBucket, newBucket;
1059         int newNumBuckets;
1060         u_int newMask;
1061
1062         /* Is table too full or too empty? */
1063         if (priv->numHosts > priv->numBuckets
1064             && (priv->numBuckets << 1) <= MAX_BUCKETS)
1065                 newNumBuckets = priv->numBuckets << 1;
1066         else if (priv->numHosts < (priv->numBuckets >> 2)
1067             && (priv->numBuckets >> 2) >= MIN_BUCKETS)
1068                 newNumBuckets = priv->numBuckets >> 2;
1069         else
1070                 return;
1071         newMask = newNumBuckets - 1;
1072
1073         /* Allocate and initialize new table */
1074         newTab = malloc(newNumBuckets * sizeof(*newTab),
1075             M_NETGRAPH_BRIDGE, M_NOWAIT | M_ZERO);
1076         if (newTab == NULL)
1077                 return;
1078
1079         /* Move all entries from old table to new table */
1080         for (oldBucket = 0; oldBucket < priv->numBuckets; oldBucket++) {
1081                 struct ng_bridge_bucket *const oldList = &priv->tab[oldBucket];
1082
1083                 while (!SLIST_EMPTY(oldList)) {
1084                         struct ng_bridge_host *const host
1085                             = SLIST_FIRST(oldList);
1086
1087                         SLIST_REMOVE_HEAD(oldList, next);
1088                         newBucket = HASH(host->addr, newMask);
1089                         SLIST_INSERT_HEAD(&newTab[newBucket], host, next);
1090                 }
1091         }
1092
1093         /* Replace old table with new one */
1094         if (priv->conf.debugLevel >= 3) {
1095                 log(LOG_INFO, "ng_bridge: %s: table size %d -> %d\n",
1096                     ng_bridge_nodename(priv->node),
1097                     priv->numBuckets, newNumBuckets);
1098         }
1099         free(priv->tab, M_NETGRAPH_BRIDGE);
1100         priv->numBuckets = newNumBuckets;
1101         priv->hashMask = newMask;
1102         priv->tab = newTab;
1103         return;
1104 }
1105
1106 /******************************************************************
1107                     MISC FUNCTIONS
1108 ******************************************************************/
1109
1110 /*
1111  * Remove all hosts associated with a specific link from the hashtable.
1112  * If linkNum == -1, then remove all hosts in the table.
1113  */
1114 static void
1115 ng_bridge_remove_hosts(priv_p priv, link_p link)
1116 {
1117         int bucket;
1118
1119         for (bucket = 0; bucket < priv->numBuckets; bucket++) {
1120                 struct ng_bridge_host **hptr = &SLIST_FIRST(&priv->tab[bucket]);
1121
1122                 while (*hptr != NULL) {
1123                         struct ng_bridge_host *const host = *hptr;
1124
1125                         if (link == NULL || host->link == link) {
1126                                 *hptr = SLIST_NEXT(host, next);
1127                                 free(host, M_NETGRAPH_BRIDGE);
1128                                 priv->numHosts--;
1129                         } else
1130                                 hptr = &SLIST_NEXT(host, next);
1131                 }
1132         }
1133 }
1134
1135 /*
1136  * Handle our once-per-second timeout event. We do two things:
1137  * we decrement link->loopCount for those links being muted due to
1138  * a detected loopback condition, and we remove any hosts from
1139  * the hashtable whom we haven't heard from in a long while.
1140  */
1141 static int
1142 ng_bridge_unmute(hook_p hook, void *arg)
1143 {
1144         link_p link = NG_HOOK_PRIVATE(hook);
1145         node_p node = NG_HOOK_NODE(hook);
1146         priv_p priv = NG_NODE_PRIVATE(node);
1147         int *counter = arg;
1148
1149         if (link->loopCount != 0) {
1150                 link->loopCount--;
1151                 if (link->loopCount == 0 && priv->conf.debugLevel >= 2) {
1152                         log(LOG_INFO, "ng_bridge: %s:"
1153                             " restoring looped back %s\n",
1154                             ng_bridge_nodename(node), NG_HOOK_NAME(hook));
1155                 }
1156         }
1157         (*counter)++;
1158         return (1);
1159 }
1160
1161 static void
1162 ng_bridge_timeout(node_p node, hook_p hook, void *arg1, int arg2)
1163 {
1164         const priv_p priv = NG_NODE_PRIVATE(node);
1165         int bucket;
1166         int counter = 0;
1167
1168         /* Update host time counters and remove stale entries */
1169         for (bucket = 0; bucket < priv->numBuckets; bucket++) {
1170                 struct ng_bridge_host **hptr = &SLIST_FIRST(&priv->tab[bucket]);
1171
1172                 while (*hptr != NULL) {
1173                         struct ng_bridge_host *const host = *hptr;
1174
1175                         /* Remove hosts we haven't heard from in a while */
1176                         if (++host->staleness >= priv->conf.maxStaleness) {
1177                                 *hptr = SLIST_NEXT(host, next);
1178                                 free(host, M_NETGRAPH_BRIDGE);
1179                                 priv->numHosts--;
1180                         } else {
1181                                 if (host->age < 0xffff)
1182                                         host->age++;
1183                                 hptr = &SLIST_NEXT(host, next);
1184                                 counter++;
1185                         }
1186                 }
1187         }
1188         KASSERT(priv->numHosts == counter,
1189             ("%s: hosts: %d != %d", __func__, priv->numHosts, counter));
1190
1191         /* Decrease table size if necessary */
1192         ng_bridge_rehash(priv);
1193
1194         /* Decrease loop counter on muted looped back links */
1195         counter = 0;
1196         NG_NODE_FOREACH_HOOK(node, ng_bridge_unmute, &counter);
1197         KASSERT(priv->numLinks == counter,
1198             ("%s: links: %d != %d", __func__, priv->numLinks, counter));
1199
1200         /* Register a new timeout, keeping the existing node reference */
1201         ng_callout(&priv->timer, node, NULL, hz, ng_bridge_timeout, NULL, 0);
1202 }
1203
1204 /*
1205  * Return node's "name", even if it doesn't have one.
1206  */
1207 static const char *
1208 ng_bridge_nodename(node_cp node)
1209 {
1210         static char name[NG_NODESIZ];
1211
1212         if (NG_NODE_HAS_NAME(node))
1213                 snprintf(name, sizeof(name), "%s", NG_NODE_NAME(node));
1214         else
1215                 snprintf(name, sizeof(name), "[%x]", ng_node2ID(node));
1216         return name;
1217 }