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                         hook_p rethook;
 536
 537                         /* Flush all entries in the hash table */
 538                         ng_bridge_remove_hosts(priv, NULL);
 539
 540                         /* Reset all loop detection counters and stats */
 541                         NG_NODE_FOREACH_HOOK(node, ng_bridge_reset_link, NULL,
 542                             rethook);
 543                         break;
 544                     }
 545                 case NGM_BRIDGE_GET_STATS:
 546                 case NGM_BRIDGE_CLR_STATS:
 547                 case NGM_BRIDGE_GETCLR_STATS:
 548                     {
 549                         hook_p hook;
 550                         link_p link;
 551                         char linkName[NG_HOOKSIZ];
 552                         int linkNum;
 553
 554                         /* Get link number */
 555                         if (msg->header.arglen != sizeof(u_int32_t)) {
 556                                 error = EINVAL;
 557                                 break;
 558                         }
 559                         linkNum = *((int32_t *)msg->data);
 560                         if (linkNum < 0)
 561                                 snprintf(linkName, sizeof(linkName),
 562                                     "%s%u", NG_BRIDGE_HOOK_UPLINK_PREFIX, -linkNum);
 563                         else
 564                                 snprintf(linkName, sizeof(linkName),
 565                                     "%s%u", NG_BRIDGE_HOOK_LINK_PREFIX, linkNum);
 566
 567                         if ((hook = ng_findhook(node, linkName)) == NULL) {
 568                                 error = ENOTCONN;
 569                                 break;
 570                         }
 571                         link = NG_HOOK_PRIVATE(hook);
 572
 573                         /* Get/clear stats */
 574                         if (msg->header.cmd != NGM_BRIDGE_CLR_STATS) {
 575                                 struct ng_bridge_link_stats *rs;
 576
 577                                 NG_MKRESPONSE(resp, msg,
 578                                     sizeof(link->stats), M_NOWAIT);
 579                                 if (resp == NULL) {
 580                                         error = ENOMEM;
 581                                         break;
 582                                 }
 583                                 rs = (struct ng_bridge_link_stats *)resp->data;
 584 #define FETCH(x)        rs->x = counter_u64_fetch(link->stats.x)
 585                                 FETCH(recvOctets);
 586                                 FETCH(recvPackets);
 587                                 FETCH(recvMulticasts);
 588                                 FETCH(recvBroadcasts);
 589                                 FETCH(recvUnknown);
 590                                 FETCH(recvRunts);
 591                                 FETCH(recvInvalid);
 592                                 FETCH(xmitOctets);
 593                                 FETCH(xmitPackets);
 594                                 FETCH(xmitMulticasts);
 595                                 FETCH(xmitBroadcasts);
 596                                 FETCH(loopDrops);
 597                                 rs->loopDetects = link->stats.loopDetects;
 598                                 FETCH(memoryFailures);
 599 #undef FETCH
 600                         }
 601                         if (msg->header.cmd != NGM_BRIDGE_GET_STATS)
 602                                 ng_bridge_clear_link_stats(&link->stats);
 603                         break;
 604                     }
 605                 case NGM_BRIDGE_GET_TABLE:
 606                     {
 607                         struct ng_bridge_host_ary *ary;
 608                         struct ng_bridge_host *host;
 609                         int i = 0, bucket;
 610
 611                         NG_MKRESPONSE(resp, msg, sizeof(*ary)
 612                             + (priv->numHosts * sizeof(*ary->hosts)), M_NOWAIT);
 613                         if (resp == NULL) {
 614                                 error = ENOMEM;
 615                                 break;
 616                         }
 617                         ary = (struct ng_bridge_host_ary *)resp->data;
 618                         ary->numHosts = priv->numHosts;
 619                         for (bucket = 0; bucket < priv->numBuckets; bucket++) {
 620                                 SLIST_FOREACH(host, &priv->tab[bucket], next) {
 621                                         memcpy(ary->hosts[i].addr,
 622                                                host->addr,
 623                                                sizeof(ary->hosts[i].addr));
 624                                         ary->hosts[i].age       = host->age;
 625                                         ary->hosts[i].staleness = host->staleness;
 626                                         strncpy(ary->hosts[i].hook,
 627                                                 NG_HOOK_NAME(host->link->hook),
 628                                                 sizeof(ary->hosts[i].hook));
 629                                         i++;
 630                                 }
 631                         }
 632                         break;
 633                     }
 634                 case NGM_BRIDGE_SET_PERSISTENT:
 635                     {
 636                         priv->persistent = 1;
 637                         break;
 638                     }
 639                 case NGM_BRIDGE_MOVE_HOST:
 640                 {
 641                         struct ng_bridge_move_host *mh;
 642                         hook_p hook;
 643
 644                         if (msg->header.arglen < sizeof(*mh)) {
 645                                 error = EINVAL;
 646                                 break;
 647                         }
 648                         mh = (struct ng_bridge_move_host *)msg->data;
 649                         hook = (mh->hook[0] == 0)
 650                             ? lasthook
 651                             : ng_findhook(node, mh->hook);
 652                         if (hook == NULL) {
 653                                 error = ENOENT;
 654                                 break;
 655                         }
 656                         error = ng_bridge_put(priv, mh->addr, NG_HOOK_PRIVATE(hook));
 657                         break;
 658                 }
 659                 default:
 660                         error = EINVAL;
 661                         break;
 662                 }
 663                 break;
 664         default:
 665                 error = EINVAL;
 666                 break;
 667         }
 668
 669         /* Done */
 670         NG_RESPOND_MSG(error, node, item, resp);
 671         NG_FREE_MSG(msg);
 672         return (error);
 673 }
 674
 675 /*
 676  * Receive data on a hook
 677  */
 678 struct ng_bridge_send_ctx {
 679         link_p foundFirst, incoming;
 680         struct mbuf * m;
 681         int manycast, error;
 682 };
 683
 684 /*
 685  * Update stats and send out
 686  */
 687 static inline int
 688 ng_bridge_send_data(link_cp dst, int manycast, struct mbuf *m, item_p item) {
 689         int error = 0;
 690         size_t len = m->m_pkthdr.len;
 691
 692         if(item != NULL)
 693                 NG_FWD_NEW_DATA(error, item, dst->hook, m);
 694         else
 695                 NG_SEND_DATA_ONLY(error, dst->hook, m);
 696
 697         if (error) {
 698                 /* The packet is still ours */
 699                 if (item != NULL)
 700                         NG_FREE_ITEM(item);
 701                 if (m != NULL)
 702                         NG_FREE_M(m);
 703                 return (error);
 704         }
 705
 706         counter_u64_add(dst->stats.xmitPackets, 1);
 707         counter_u64_add(dst->stats.xmitOctets, len);
 708         switch (manycast) {
 709         default:                       /* unknown unicast */
 710                 break;
 711         case 1:                        /* multicast */
 712                 counter_u64_add(dst->stats.xmitMulticasts, 1);
 713                 break;
 714         case 2:                        /* broadcast */
 715                 counter_u64_add(dst->stats.xmitBroadcasts, 1);
 716                 break;
 717         }
 718         return (0);
 719 }
 720
 721 /*
 722  * Loop body for sending to multiple destinations
 723  * return 0 to stop looping
 724  */
 725 static int
 726 ng_bridge_send_ctx(hook_p dst, void *arg)
 727 {
 728         struct ng_bridge_send_ctx *ctx = arg;
 729         link_p destLink = NG_HOOK_PRIVATE(dst);
 730         struct mbuf *m2 = NULL;
 731         int error = 0;
 732
 733         /* Skip incoming link */
 734         if (destLink == ctx->incoming) {
 735                 return (1);
 736         }
 737
 738         /* Skip sending unknowns to undesired links  */
 739         if (!ctx->manycast && !destLink->sendUnknown)
 740                 return (1);
 741
 742         if (ctx->foundFirst == NULL) {
 743                 /*
 744                  * This is the first usable link we have found.
 745                  * Reserve it for the originals.
 746                  * If we never find another we save a copy.
 747                  */
 748                 ctx->foundFirst = destLink;
 749                 return (1);
 750         }
 751
 752         /*
 753          * It's usable link but not the reserved (first) one.
 754          * Copy mbuf info for sending.
 755          */
 756         m2 = m_dup(ctx->m, M_NOWAIT);
 757         if (m2 == NULL) {
 758                 counter_u64_add(ctx->incoming->stats.memoryFailures, 1);
 759                 ctx->error = ENOBUFS;
 760                 return (0);            /* abort loop, do not try again and again */
 761         }
 762
 763         /* Send packet */
 764         error = ng_bridge_send_data(destLink, ctx->manycast, m2, NULL);
 765         if (error)
 766           ctx->error = error;
 767         return (1);
 768 }
 769
 770 static int
 771 ng_bridge_rcvdata(hook_p hook, item_p item)
 772 {
 773         const node_p node = NG_HOOK_NODE(hook);
 774         const priv_p priv = NG_NODE_PRIVATE(node);
 775         struct ng_bridge_host *host;
 776         struct ether_header *eh;
 777         struct ng_bridge_send_ctx ctx = { 0 };
 778         hook_p ret;
 779
 780         NGI_GET_M(item, ctx.m);
 781
 782         ctx.incoming = NG_HOOK_PRIVATE(hook);
 783         /* Sanity check packet and pull up header */
 784         if (ctx.m->m_pkthdr.len < ETHER_HDR_LEN) {
 785                 counter_u64_add(ctx.incoming->stats.recvRunts, 1);
 786                 NG_FREE_ITEM(item);
 787                 NG_FREE_M(ctx.m);
 788                 return (EINVAL);
 789         }
 790         if (ctx.m->m_len < ETHER_HDR_LEN && !(ctx.m = m_pullup(ctx.m, ETHER_HDR_LEN))) {
 791                 counter_u64_add(ctx.incoming->stats.memoryFailures, 1);
 792                 NG_FREE_ITEM(item);
 793                 return (ENOBUFS);
 794         }
 795         eh = mtod(ctx.m, struct ether_header *);
 796         if ((eh->ether_shost[0] & 1) != 0) {
 797                 counter_u64_add(ctx.incoming->stats.recvInvalid, 1);
 798                 NG_FREE_ITEM(item);
 799                 NG_FREE_M(ctx.m);
 800                 return (EINVAL);
 801         }
 802
 803         /* Is link disabled due to a loopback condition? */
 804         if (ctx.incoming->loopCount != 0) {
 805                 counter_u64_add(ctx.incoming->stats.loopDrops, 1);
 806                 NG_FREE_ITEM(item);
 807                 NG_FREE_M(ctx.m);
 808                 return (ELOOP);
 809         }
 810
 811         /* Update stats */
 812         counter_u64_add(ctx.incoming->stats.recvPackets, 1);
 813         counter_u64_add(ctx.incoming->stats.recvOctets, ctx.m->m_pkthdr.len);
 814         if ((ctx.manycast = (eh->ether_dhost[0] & 1)) != 0) {
 815                 if (ETHER_EQUAL(eh->ether_dhost, ng_bridge_bcast_addr)) {
 816                         counter_u64_add(ctx.incoming->stats.recvBroadcasts, 1);
 817                         ctx.manycast = 2;
 818                 } else
 819                         counter_u64_add(ctx.incoming->stats.recvMulticasts, 1);
 820         }
 821
 822         /* Look up packet's source Ethernet address in hashtable */
 823         if ((host = ng_bridge_get(priv, eh->ether_shost)) != NULL)
 824                 /* Update time since last heard from this host.
 825                  * This is safe without locking, because it's
 826                  * the only operation during shared access.
 827                  */
 828                 if (__predict_false(host->staleness > 0))
 829                         host->staleness = 0;
 830
 831         if ((host == NULL && ctx.incoming->learnMac) ||
 832             (host != NULL && host->link != ctx.incoming)) {
 833                 struct ng_mesg *msg;
 834                 struct ng_bridge_move_host *mh;
 835                 int error = 0;
 836
 837                 NG_MKMESSAGE(msg, NGM_BRIDGE_COOKIE, NGM_BRIDGE_MOVE_HOST,
 838                     sizeof(*mh), M_NOWAIT);
 839                 if (msg == NULL) {
 840                         counter_u64_add(ctx.incoming->stats.memoryFailures, 1);
 841                         NG_FREE_ITEM(item);
 842                         NG_FREE_M(ctx.m);
 843                         return (ENOMEM);
 844                 }
 845                 mh = (struct ng_bridge_move_host *)msg->data;
 846                 strncpy(mh->hook, NG_HOOK_NAME(ctx.incoming->hook),
 847                     sizeof(mh->hook));
 848                 memcpy(mh->addr, eh->ether_shost, sizeof(mh->addr));
 849                 NG_SEND_MSG_ID(error, node, msg, NG_NODE_ID(node),
 850                     NG_NODE_ID(node));
 851                 if (error)
 852                         counter_u64_add(ctx.incoming->stats.memoryFailures, 1);
 853         }
 854
 855         if (host != NULL && host->link != ctx.incoming) {
 856                 if (host->age < priv->conf.minStableAge) {
 857                         /* Drop packet on instable links */
 858                         counter_u64_add(ctx.incoming->stats.loopDrops, 1);
 859                         NG_FREE_ITEM(item);
 860                         NG_FREE_M(ctx.m);
 861                         return (ELOOP);
 862                 }
 863         }
 864
 865         /* Run packet through ipfw processing, if enabled */
 866 #if 0
 867         if (priv->conf.ipfw[linkNum] && V_fw_enable && V_ip_fw_chk_ptr != NULL) {
 868                 /* XXX not implemented yet */
 869         }
 870 #endif
 871
 872         /*
 873          * If unicast and destination host known, deliver to host's link,
 874          * unless it is the same link as the packet came in on.
 875          */
 876         if (!ctx.manycast) {
 877                 /* Determine packet destination link */
 878                 if ((host = ng_bridge_get(priv, eh->ether_dhost)) != NULL) {
 879                         link_p destLink = host->link;
 880
 881                         /* If destination same as incoming link, do nothing */
 882                         if (destLink == ctx.incoming) {
 883                                 NG_FREE_ITEM(item);
 884                                 NG_FREE_M(ctx.m);
 885                                 return (0);
 886                         }
 887
 888                         /* Deliver packet out the destination link */
 889                         return (ng_bridge_send_data(destLink, ctx.manycast, ctx.m, item));
 890                 }
 891
 892                 /* Destination host is not known */
 893                 counter_u64_add(ctx.incoming->stats.recvUnknown, 1);
 894         }
 895
 896         /* Distribute unknown, multicast, broadcast pkts to all other links */
 897         NG_NODE_FOREACH_HOOK(node, ng_bridge_send_ctx, &ctx, ret);
 898
 899         /* Finally send out on the first link found */
 900         if (ctx.foundFirst != NULL) {
 901                 int error = ng_bridge_send_data(ctx.foundFirst, ctx.manycast, ctx.m, item);
 902                 if (error)
 903                         ctx.error = error;
 904         } else {                       /* nothing to send at all */
 905                 NG_FREE_ITEM(item);
 906                 NG_FREE_M(ctx.m);
 907         }
 908
 909         return (ctx.error);
 910 }
 911
 912 /*
 913  * Shutdown node
 914  */
 915 static int
 916 ng_bridge_shutdown(node_p node)
 917 {
 918         const priv_p priv = NG_NODE_PRIVATE(node);
 919
 920         /*
 921          * Shut down everything including the timer.  Even if the
 922          * callout has already been dequeued and is about to be
 923          * run, ng_bridge_timeout() won't be fired as the node
 924          * is already marked NGF_INVALID, so we're safe to free
 925          * the node now.
 926          */
 927         KASSERT(priv->numLinks == 0 && priv->numHosts == 0,
 928             ("%s: numLinks=%d numHosts=%d",
 929             __func__, priv->numLinks, priv->numHosts));
 930         ng_uncallout(&priv->timer, node);
 931         NG_NODE_SET_PRIVATE(node, NULL);
 932         NG_NODE_UNREF(node);
 933         free(priv->tab, M_NETGRAPH_BRIDGE);
 934         free(priv, M_NETGRAPH_BRIDGE);
 935         return (0);
 936 }
 937
 938 /*
 939  * Hook disconnection.
 940  */
 941 static int
 942 ng_bridge_disconnect(hook_p hook)
 943 {
 944         const priv_p priv = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
 945         link_p link = NG_HOOK_PRIVATE(hook);
 946
 947         /* Remove all hosts associated with this link */
 948         ng_bridge_remove_hosts(priv, link);
 949
 950         /* Free associated link information */
 951         ng_bridge_free_link(link);
 952         priv->numLinks--;
 953
 954         /* If no more hooks, go away */
 955         if ((NG_NODE_NUMHOOKS(NG_HOOK_NODE(hook)) == 0)
 956             && (NG_NODE_IS_VALID(NG_HOOK_NODE(hook)))
 957             && !priv->persistent) {
 958                 ng_rmnode_self(NG_HOOK_NODE(hook));
 959         }
 960         return (0);
 961 }
 962
 963 /******************************************************************
 964                     HASH TABLE FUNCTIONS
 965 ******************************************************************/
 966
 967 /*
 968  * Hash algorithm
 969  */
 970 #define HASH(addr,mask)         ( (((const u_int16_t *)(addr))[0]       \
 971                                  ^ ((const u_int16_t *)(addr))[1]       \
 972                                  ^ ((const u_int16_t *)(addr))[2]) & (mask) )
 973
 974 /*
 975  * Find a host entry in the table.
 976  */
 977 static struct ng_bridge_host *
 978 ng_bridge_get(priv_cp priv, const u_char *addr)
 979 {
 980         const int bucket = HASH(addr, priv->hashMask);
 981         struct ng_bridge_host *host;
 982
 983         SLIST_FOREACH(host, &priv->tab[bucket], next) {
 984                 if (ETHER_EQUAL(host->addr, addr))
 985                         return (host);
 986         }
 987         return (NULL);
 988 }
 989
 990 /*
 991  * Add a host entry to the table. If it already exists, move it
 992  * to the new link. Returns 0 on success.
 993  */
 994 static int
 995 ng_bridge_put(priv_p priv, const u_char *addr, link_p link)
 996 {
 997         const int bucket = HASH(addr, priv->hashMask);
 998         struct ng_bridge_host *host;
 999
1000         if ((host = ng_bridge_get(priv, addr)) != NULL) {
1001                 /* Host already on the correct link? */
1002                 if (host->link == link)
1003                         return 0;
1004
1005                 /* Move old host over to new link */
1006                 if (host->age >= priv->conf.minStableAge) {
1007                         host->link = link;
1008                         host->age = 0;
1009                         return (0);
1010                 }
1011                 /*
1012                  * If the host was recently moved to the old link and
1013                  * it's now jumping to a new link, declare a loopback
1014                  * condition.
1015                  */
1016                 if (priv->conf.debugLevel >= 2)
1017                     log(LOG_WARNING, "ng_bridge: %s:"
1018                         " loopback detected on %s\n",
1019                         ng_bridge_nodename(priv->node),
1020                         NG_HOOK_NAME(link->hook));
1021
1022                 /* Mark link as linka non grata */
1023                 link->loopCount = priv->conf.loopTimeout;
1024                 link->stats.loopDetects++;
1025
1026                 /* Forget all hosts on this link */
1027                 ng_bridge_remove_hosts(priv, link);
1028                 return (ELOOP);
1029         }
1030
1031         /* Allocate and initialize new hashtable entry */
1032         host = malloc(sizeof(*host), M_NETGRAPH_BRIDGE, M_NOWAIT);
1033         if (host == NULL)
1034                 return (ENOMEM);
1035         bcopy(addr, host->addr, ETHER_ADDR_LEN);
1036         host->link = link;
1037         host->staleness = 0;
1038         host->age = 0;
1039
1040         /* Add new element to hash bucket */
1041         SLIST_INSERT_HEAD(&priv->tab[bucket], host, next);
1042         priv->numHosts++;
1043
1044         /* Resize table if necessary */
1045         ng_bridge_rehash(priv);
1046         return (0);
1047 }
1048
1049 /*
1050  * Resize the hash table. We try to maintain the number of buckets
1051  * such that the load factor is in the range 0.25 to 1.0.
1052  *
1053  * If we can't get the new memory then we silently fail. This is OK
1054  * because things will still work and we'll try again soon anyway.
1055  */
1056 static void
1057 ng_bridge_rehash(priv_p priv)
1058 {
1059         struct ng_bridge_bucket *newTab;
1060         int oldBucket, newBucket;
1061         int newNumBuckets;
1062         u_int newMask;
1063
1064         /* Is table too full or too empty? */
1065         if (priv->numHosts > priv->numBuckets
1066             && (priv->numBuckets << 1) <= MAX_BUCKETS)
1067                 newNumBuckets = priv->numBuckets << 1;
1068         else if (priv->numHosts < (priv->numBuckets >> 2)
1069             && (priv->numBuckets >> 2) >= MIN_BUCKETS)
1070                 newNumBuckets = priv->numBuckets >> 2;
1071         else
1072                 return;
1073         newMask = newNumBuckets - 1;
1074
1075         /* Allocate and initialize new table */
1076         newTab = malloc(newNumBuckets * sizeof(*newTab),
1077             M_NETGRAPH_BRIDGE, M_NOWAIT | M_ZERO);
1078         if (newTab == NULL)
1079                 return;
1080
1081         /* Move all entries from old table to new table */
1082         for (oldBucket = 0; oldBucket < priv->numBuckets; oldBucket++) {
1083                 struct ng_bridge_bucket *const oldList = &priv->tab[oldBucket];
1084
1085                 while (!SLIST_EMPTY(oldList)) {
1086                         struct ng_bridge_host *const host
1087                             = SLIST_FIRST(oldList);
1088
1089                         SLIST_REMOVE_HEAD(oldList, next);
1090                         newBucket = HASH(host->addr, newMask);
1091                         SLIST_INSERT_HEAD(&newTab[newBucket], host, next);
1092                 }
1093         }
1094
1095         /* Replace old table with new one */
1096         if (priv->conf.debugLevel >= 3) {
1097                 log(LOG_INFO, "ng_bridge: %s: table size %d -> %d\n",
1098                     ng_bridge_nodename(priv->node),
1099                     priv->numBuckets, newNumBuckets);
1100         }
1101         free(priv->tab, M_NETGRAPH_BRIDGE);
1102         priv->numBuckets = newNumBuckets;
1103         priv->hashMask = newMask;
1104         priv->tab = newTab;
1105         return;
1106 }
1107
1108 /******************************************************************
1109                     MISC FUNCTIONS
1110 ******************************************************************/
1111
1112 /*
1113  * Remove all hosts associated with a specific link from the hashtable.
1114  * If linkNum == -1, then remove all hosts in the table.
1115  */
1116 static void
1117 ng_bridge_remove_hosts(priv_p priv, link_p link)
1118 {
1119         int bucket;
1120
1121         for (bucket = 0; bucket < priv->numBuckets; bucket++) {
1122                 struct ng_bridge_host **hptr = &SLIST_FIRST(&priv->tab[bucket]);
1123
1124                 while (*hptr != NULL) {
1125                         struct ng_bridge_host *const host = *hptr;
1126
1127                         if (link == NULL || host->link == link) {
1128                                 *hptr = SLIST_NEXT(host, next);
1129                                 free(host, M_NETGRAPH_BRIDGE);
1130                                 priv->numHosts--;
1131                         } else
1132                                 hptr = &SLIST_NEXT(host, next);
1133                 }
1134         }
1135 }
1136
1137 /*
1138  * Handle our once-per-second timeout event. We do two things:
1139  * we decrement link->loopCount for those links being muted due to
1140  * a detected loopback condition, and we remove any hosts from
1141  * the hashtable whom we haven't heard from in a long while.
1142  */
1143 static int
1144 ng_bridge_unmute(hook_p hook, void *arg)
1145 {
1146         link_p link = NG_HOOK_PRIVATE(hook);
1147         node_p node = NG_HOOK_NODE(hook);
1148         priv_p priv = NG_NODE_PRIVATE(node);
1149         int *counter = arg;
1150
1151         if (link->loopCount != 0) {
1152                 link->loopCount--;
1153                 if (link->loopCount == 0 && priv->conf.debugLevel >= 2) {
1154                         log(LOG_INFO, "ng_bridge: %s:"
1155                             " restoring looped back %s\n",
1156                             ng_bridge_nodename(node), NG_HOOK_NAME(hook));
1157                 }
1158         }
1159         (*counter)++;
1160         return (1);
1161 }
1162
1163 static void
1164 ng_bridge_timeout(node_p node, hook_p hook, void *arg1, int arg2)
1165 {
1166         const priv_p priv = NG_NODE_PRIVATE(node);
1167         int bucket;
1168         int counter = 0;
1169         hook_p ret;
1170
1171         /* Update host time counters and remove stale entries */
1172         for (bucket = 0; bucket < priv->numBuckets; bucket++) {
1173                 struct ng_bridge_host **hptr = &SLIST_FIRST(&priv->tab[bucket]);
1174
1175                 while (*hptr != NULL) {
1176                         struct ng_bridge_host *const host = *hptr;
1177
1178                         /* Remove hosts we haven't heard from in a while */
1179                         if (++host->staleness >= priv->conf.maxStaleness) {
1180                                 *hptr = SLIST_NEXT(host, next);
1181                                 free(host, M_NETGRAPH_BRIDGE);
1182                                 priv->numHosts--;
1183                         } else {
1184                                 if (host->age < 0xffff)
1185                                         host->age++;
1186                                 hptr = &SLIST_NEXT(host, next);
1187                                 counter++;
1188                         }
1189                 }
1190         }
1191         KASSERT(priv->numHosts == counter,
1192             ("%s: hosts: %d != %d", __func__, priv->numHosts, counter));
1193
1194         /* Decrease table size if necessary */
1195         ng_bridge_rehash(priv);
1196
1197         /* Decrease loop counter on muted looped back links */
1198         counter = 0;
1199         NG_NODE_FOREACH_HOOK(node, ng_bridge_unmute, &counter, ret);
1200         KASSERT(priv->numLinks == counter,
1201             ("%s: links: %d != %d", __func__, priv->numLinks, counter));
1202
1203         /* Register a new timeout, keeping the existing node reference */
1204         ng_callout(&priv->timer, node, NULL, hz, ng_bridge_timeout, NULL, 0);
1205 }
1206
1207 /*
1208  * Return node's "name", even if it doesn't have one.
1209  */
1210 static const char *
1211 ng_bridge_nodename(node_cp node)
1212 {
1213         static char name[NG_NODESIZ];
1214
1215         if (NG_NODE_HAS_NAME(node))
1216                 snprintf(name, sizeof(name), "%s", NG_NODE_NAME(node));
1217         else
1218                 snprintf(name, sizeof(name), "[%x]", ng_node2ID(node));
1219         return name;
1220 }