sys/netgraph/bridge/ng_bridge.c

   1
   2 /*
   3  * ng_bridge.c
   4  *
   5  * Copyright (c) 2000 Whistle Communications, Inc.
   6  * All rights reserved.
   7  *
   8  * Subject to the following obligations and disclaimer of warranty, use and
   9  * redistribution of this software, in source or object code forms, with or
  10  * without modifications are expressly permitted by Whistle Communications;
  11  * provided, however, that:
  12  * 1. Any and all reproductions of the source or object code must include the
  13  *    copyright notice above and the following disclaimer of warranties; and
  14  * 2. No rights are granted, in any manner or form, to use Whistle
  15  *    Communications, Inc. trademarks, including the mark "WHISTLE
  16  *    COMMUNICATIONS" on advertising, endorsements, or otherwise except as
  17  *    such appears in the above copyright notice or in the software.
  18  *
  19  * THIS SOFTWARE IS BEING PROVIDED BY WHISTLE COMMUNICATIONS "AS IS", AND
  20  * TO THE MAXIMUM EXTENT PERMITTED BY LAW, WHISTLE COMMUNICATIONS MAKES NO
  21  * REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED, REGARDING THIS SOFTWARE,
  22  * INCLUDING WITHOUT LIMITATION, ANY AND ALL IMPLIED WARRANTIES OF
  23  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT.
  24  * WHISTLE COMMUNICATIONS DOES NOT WARRANT, GUARANTEE, OR MAKE ANY
  25  * REPRESENTATIONS REGARDING THE USE OF, OR THE RESULTS OF THE USE OF THIS
  26  * SOFTWARE IN TERMS OF ITS CORRECTNESS, ACCURACY, RELIABILITY OR OTHERWISE.
  27  * IN NO EVENT SHALL WHISTLE COMMUNICATIONS BE LIABLE FOR ANY DAMAGES
  28  * RESULTING FROM OR ARISING OUT OF ANY USE OF THIS SOFTWARE, INCLUDING
  29  * WITHOUT LIMITATION, ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
  30  * PUNITIVE, OR CONSEQUENTIAL DAMAGES, PROCUREMENT OF SUBSTITUTE GOODS OR
  31  * SERVICES, LOSS OF USE, DATA OR PROFITS, HOWEVER CAUSED AND UNDER ANY
  32  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  33  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  34  * THIS SOFTWARE, EVEN IF WHISTLE COMMUNICATIONS IS ADVISED OF THE POSSIBILITY
  35  * OF SUCH DAMAGE.
  36  *
  37  * Author: Archie Cobbs <archie@freebsd.org>
  38  *
  39  * $FreeBSD: src/sys/netgraph/ng_bridge.c,v 1.1.2.5 2002/07/02 23:44:02 archie Exp $
  40  * $DragonFly: src/sys/netgraph/bridge/ng_bridge.c,v 1.10 2007/06/03 20:51:12 dillon Exp $
  41  */
  42
  43 /*
  44  * ng_bridge(4) netgraph node type
  45  *
  46  * The node performs standard intelligent Ethernet bridging over
  47  * each of its connected hooks, or links.  A simple loop detection
  48  * algorithm is included which disables a link for priv->conf.loopTimeout
  49  * seconds when a host is seen to have jumped from one link to
  50  * another within priv->conf.minStableAge seconds.
  51  *
  52  * We keep a hashtable that maps Ethernet addresses to host info,
  53  * which is contained in struct ng_bridge_host's. These structures
  54  * tell us on which link the host may be found. A host's entry will
  55  * expire after priv->conf.maxStaleness seconds.
  56  *
  57  * This node is optimzed for stable networks, where machines jump
  58  * from one port to the other only rarely.
  59  */
  60
  61 #include <sys/param.h>
  62 #include <sys/systm.h>
  63 #include <sys/kernel.h>
  64 #include <sys/malloc.h>
  65 #include <sys/mbuf.h>
  66 #include <sys/errno.h>
  67 #include <sys/syslog.h>
  68 #include <sys/socket.h>
  69 #include <sys/ctype.h>
  70 #include <sys/thread2.h>
  71
  72 #include <net/if.h>
  73 #include <net/ethernet.h>
  74
  75 #include <netinet/in.h>
  76 #include <net/ipfw/ip_fw.h>
  77
  78 #include <netgraph/ng_message.h>
  79 #include <netgraph/netgraph.h>
  80 #include <netgraph/ng_parse.h>
  81 #include "ng_bridge.h"
  82 #include <netgraph/ether/ng_ether.h>
  83
  84 /* Per-link private data */
  85 struct ng_bridge_link {
  86         hook_p                          hook;           /* netgraph hook */
  87         u_int16_t                       loopCount;      /* loop ignore timer */
  88         struct ng_bridge_link_stats     stats;          /* link stats */
  89 };
  90
  91 /* Per-node private data */
  92 struct ng_bridge_private {
  93         struct ng_bridge_bucket *tab;           /* hash table bucket array */
  94         struct ng_bridge_link   *links[NG_BRIDGE_MAX_LINKS];
  95         struct ng_bridge_config conf;           /* node configuration */
  96         node_p                  node;           /* netgraph node */
  97         u_int                   numHosts;       /* num entries in table */
  98         u_int                   numBuckets;     /* num buckets in table */
  99         u_int                   hashMask;       /* numBuckets - 1 */
 100         int                     numLinks;       /* num connected links */
 101         struct callout          timer;          /* one second periodic timer */
 102 };
 103 typedef struct ng_bridge_private *priv_p;
 104
 105 /* Information about a host, stored in a hash table entry */
 106 struct ng_bridge_hent {
 107         struct ng_bridge_host           host;   /* actual host info */
 108         SLIST_ENTRY(ng_bridge_hent)     next;   /* next entry in bucket */
 109 };
 110
 111 /* Hash table bucket declaration */
 112 SLIST_HEAD(ng_bridge_bucket, ng_bridge_hent);
 113
 114 /* Netgraph node methods */
 115 static ng_constructor_t ng_bridge_constructor;
 116 static ng_rcvmsg_t      ng_bridge_rcvmsg;
 117 static ng_shutdown_t    ng_bridge_rmnode;
 118 static ng_newhook_t     ng_bridge_newhook;
 119 static ng_rcvdata_t     ng_bridge_rcvdata;
 120 static ng_disconnect_t  ng_bridge_disconnect;
 121
 122 /* Other internal functions */
 123 static struct   ng_bridge_host *ng_bridge_get(priv_p priv, const u_char *addr);
 124 static int      ng_bridge_put(priv_p priv, const u_char *addr, int linkNum);
 125 static void     ng_bridge_rehash(priv_p priv);
 126 static void     ng_bridge_remove_hosts(priv_p priv, int linkNum);
 127 static void     ng_bridge_timeout(void *arg);
 128 static const    char *ng_bridge_nodename(node_p node);
 129
 130 /* Ethernet broadcast */
 131 static const u_char ng_bridge_bcast_addr[ETHER_ADDR_LEN] =
 132     { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
 133
 134 /* Store each hook's link number in the private field */
 135 #define LINK_NUM(hook)          (*(u_int16_t *)(&(hook)->private))
 136
 137 /* Compare Ethernet addresses using 32 and 16 bit words instead of bytewise */
 138 #define ETHER_EQUAL(a,b)        (((const u_int32_t *)(a))[0] \
 139                                         == ((const u_int32_t *)(b))[0] \
 140                                     && ((const u_int16_t *)(a))[2] \
 141                                         == ((const u_int16_t *)(b))[2])
 142
 143 /* Minimum and maximum number of hash buckets. Must be a power of two. */
 144 #define MIN_BUCKETS             (1 << 5)        /* 32 */
 145 #define MAX_BUCKETS             (1 << 14)       /* 16384 */
 146
 147 /* Configuration default values */
 148 #define DEFAULT_LOOP_TIMEOUT    60
 149 #define DEFAULT_MAX_STALENESS   (15 * 60)       /* same as ARP timeout */
 150 #define DEFAULT_MIN_STABLE_AGE  1
 151
 152 /******************************************************************
 153                     NETGRAPH PARSE TYPES
 154 ******************************************************************/
 155
 156 /*
 157  * How to determine the length of the table returned by NGM_BRIDGE_GET_TABLE
 158  */
 159 static int
 160 ng_bridge_getTableLength(const struct ng_parse_type *type,
 161         const u_char *start, const u_char *buf)
 162 {
 163         const struct ng_bridge_host_ary *const hary
 164             = (const struct ng_bridge_host_ary *)(buf - sizeof(u_int32_t));
 165
 166         return hary->numHosts;
 167 }
 168
 169 /* Parse type for struct ng_bridge_host_ary */
 170 static const struct ng_parse_struct_field ng_bridge_host_type_fields[]
 171         = NG_BRIDGE_HOST_TYPE_INFO(&ng_ether_enaddr_type);
 172 static const struct ng_parse_type ng_bridge_host_type = {
 173         &ng_parse_struct_type,
 174         &ng_bridge_host_type_fields
 175 };
 176 static const struct ng_parse_array_info ng_bridge_hary_type_info = {
 177         &ng_bridge_host_type,
 178         ng_bridge_getTableLength
 179 };
 180 static const struct ng_parse_type ng_bridge_hary_type = {
 181         &ng_parse_array_type,
 182         &ng_bridge_hary_type_info
 183 };
 184 static const struct ng_parse_struct_field ng_bridge_host_ary_type_fields[]
 185         = NG_BRIDGE_HOST_ARY_TYPE_INFO(&ng_bridge_hary_type);
 186 static const struct ng_parse_type ng_bridge_host_ary_type = {
 187         &ng_parse_struct_type,
 188         &ng_bridge_host_ary_type_fields
 189 };
 190
 191 /* Parse type for struct ng_bridge_config */
 192 static const struct ng_parse_fixedarray_info ng_bridge_ipfwary_type_info = {
 193         &ng_parse_uint8_type,
 194         NG_BRIDGE_MAX_LINKS
 195 };
 196 static const struct ng_parse_type ng_bridge_ipfwary_type = {
 197         &ng_parse_fixedarray_type,
 198         &ng_bridge_ipfwary_type_info
 199 };
 200 static const struct ng_parse_struct_field ng_bridge_config_type_fields[]
 201         = NG_BRIDGE_CONFIG_TYPE_INFO(&ng_bridge_ipfwary_type);
 202 static const struct ng_parse_type ng_bridge_config_type = {
 203         &ng_parse_struct_type,
 204         &ng_bridge_config_type_fields
 205 };
 206
 207 /* Parse type for struct ng_bridge_link_stat */
 208 static const struct ng_parse_struct_field ng_bridge_stats_type_fields[]
 209         = NG_BRIDGE_STATS_TYPE_INFO;
 210 static const struct ng_parse_type ng_bridge_stats_type = {
 211         &ng_parse_struct_type,
 212         &ng_bridge_stats_type_fields
 213 };
 214
 215 /* List of commands and how to convert arguments to/from ASCII */
 216 static const struct ng_cmdlist ng_bridge_cmdlist[] = {
 217         {
 218           NGM_BRIDGE_COOKIE,
 219           NGM_BRIDGE_SET_CONFIG,
 220           "setconfig",
 221           &ng_bridge_config_type,
 222           NULL
 223         },
 224         {
 225           NGM_BRIDGE_COOKIE,
 226           NGM_BRIDGE_GET_CONFIG,
 227           "getconfig",
 228           NULL,
 229           &ng_bridge_config_type
 230         },
 231         {
 232           NGM_BRIDGE_COOKIE,
 233           NGM_BRIDGE_RESET,
 234           "reset",
 235           NULL,
 236           NULL
 237         },
 238         {
 239           NGM_BRIDGE_COOKIE,
 240           NGM_BRIDGE_GET_STATS,
 241           "getstats",
 242           &ng_parse_uint32_type,
 243           &ng_bridge_stats_type
 244         },
 245         {
 246           NGM_BRIDGE_COOKIE,
 247           NGM_BRIDGE_CLR_STATS,
 248           "clrstats",
 249           &ng_parse_uint32_type,
 250           NULL
 251         },
 252         {
 253           NGM_BRIDGE_COOKIE,
 254           NGM_BRIDGE_GETCLR_STATS,
 255           "getclrstats",
 256           &ng_parse_uint32_type,
 257           &ng_bridge_stats_type
 258         },
 259         {
 260           NGM_BRIDGE_COOKIE,
 261           NGM_BRIDGE_GET_TABLE,
 262           "gettable",
 263           NULL,
 264           &ng_bridge_host_ary_type
 265         },
 266         { 0 }
 267 };
 268
 269 /* Node type descriptor */
 270 static struct ng_type ng_bridge_typestruct = {
 271         NG_VERSION,
 272         NG_BRIDGE_NODE_TYPE,
 273         NULL,
 274         ng_bridge_constructor,
 275         ng_bridge_rcvmsg,
 276         ng_bridge_rmnode,
 277         ng_bridge_newhook,
 278         NULL,
 279         NULL,
 280         ng_bridge_rcvdata,
 281         ng_bridge_rcvdata,
 282         ng_bridge_disconnect,
 283         ng_bridge_cmdlist,
 284 };
 285 NETGRAPH_INIT(bridge, &ng_bridge_typestruct);
 286
 287 /* Depend on ng_ether so we can use the Ethernet parse type */
 288 MODULE_DEPEND(ng_bridge, ng_ether, 1, 1, 1);
 289
 290 /******************************************************************
 291                     NETGRAPH NODE METHODS
 292 ******************************************************************/
 293
 294 /*
 295  * Node constructor
 296  */
 297 static int
 298 ng_bridge_constructor(node_p *nodep)
 299 {
 300         priv_p priv;
 301         int error;
 302
 303         /* Allocate and initialize private info */
 304         MALLOC(priv, priv_p, sizeof(*priv), M_NETGRAPH, M_NOWAIT);
 305         if (priv == NULL)
 306                 return (ENOMEM);
 307         bzero(priv, sizeof(*priv));
 308         callout_init(&priv->timer);
 309
 310         /* Allocate and initialize hash table, etc. */
 311         MALLOC(priv->tab, struct ng_bridge_bucket *,
 312             MIN_BUCKETS * sizeof(*priv->tab), M_NETGRAPH, M_NOWAIT);
 313         if (priv->tab == NULL) {
 314                 FREE(priv, M_NETGRAPH);
 315                 return (ENOMEM);
 316         }
 317         bzero(priv->tab, MIN_BUCKETS * sizeof(*priv->tab));  /* init SLIST's */
 318         priv->numBuckets = MIN_BUCKETS;
 319         priv->hashMask = MIN_BUCKETS - 1;
 320         priv->conf.debugLevel = 1;
 321         priv->conf.loopTimeout = DEFAULT_LOOP_TIMEOUT;
 322         priv->conf.maxStaleness = DEFAULT_MAX_STALENESS;
 323         priv->conf.minStableAge = DEFAULT_MIN_STABLE_AGE;
 324
 325         /* Call superclass constructor */
 326         if ((error = ng_make_node_common(&ng_bridge_typestruct, nodep))) {
 327                 FREE(priv, M_NETGRAPH);
 328                 return (error);
 329         }
 330         (*nodep)->private = priv;
 331         priv->node = *nodep;
 332
 333         /* Start timer; timer is always running while node is alive */
 334         callout_reset(&priv->timer, hz, ng_bridge_timeout, priv->node);
 335
 336         /* Done */
 337         return (0);
 338 }
 339
 340 /*
 341  * Method for attaching a new hook
 342  */
 343 static  int
 344 ng_bridge_newhook(node_p node, hook_p hook, const char *name)
 345 {
 346         const priv_p priv = node->private;
 347
 348         /* Check for a link hook */
 349         if (strncmp(name, NG_BRIDGE_HOOK_LINK_PREFIX,
 350             strlen(NG_BRIDGE_HOOK_LINK_PREFIX)) == 0) {
 351                 const char *cp;
 352                 char *eptr;
 353                 u_long linkNum;
 354
 355                 cp = name + strlen(NG_BRIDGE_HOOK_LINK_PREFIX);
 356                 if (!isdigit(*cp) || (cp[0] == '0' && cp[1] != '\0'))
 357                         return (EINVAL);
 358                 linkNum = strtoul(cp, &eptr, 10);
 359                 if (*eptr != '\0' || linkNum >= NG_BRIDGE_MAX_LINKS)
 360                         return (EINVAL);
 361                 if (priv->links[linkNum] != NULL)
 362                         return (EISCONN);
 363                 MALLOC(priv->links[linkNum], struct ng_bridge_link *,
 364                     sizeof(*priv->links[linkNum]), M_NETGRAPH, M_NOWAIT);
 365                 if (priv->links[linkNum] == NULL)
 366                         return (ENOMEM);
 367                 bzero(priv->links[linkNum], sizeof(*priv->links[linkNum]));
 368                 priv->links[linkNum]->hook = hook;
 369                 LINK_NUM(hook) = linkNum;
 370                 priv->numLinks++;
 371                 return (0);
 372         }
 373
 374         /* Unknown hook name */
 375         return (EINVAL);
 376 }
 377
 378 /*
 379  * Receive a control message
 380  */
 381 static int
 382 ng_bridge_rcvmsg(node_p node, struct ng_mesg *msg,
 383         const char *retaddr, struct ng_mesg **rptr)
 384 {
 385         const priv_p priv = node->private;
 386         struct ng_mesg *resp = NULL;
 387         int error = 0;
 388
 389         switch (msg->header.typecookie) {
 390         case NGM_BRIDGE_COOKIE:
 391                 switch (msg->header.cmd) {
 392                 case NGM_BRIDGE_GET_CONFIG:
 393                     {
 394                         struct ng_bridge_config *conf;
 395
 396                         NG_MKRESPONSE(resp, msg,
 397                             sizeof(struct ng_bridge_config), M_NOWAIT);
 398                         if (resp == NULL) {
 399                                 error = ENOMEM;
 400                                 break;
 401                         }
 402                         conf = (struct ng_bridge_config *)resp->data;
 403                         *conf = priv->conf;     /* no sanity checking needed */
 404                         break;
 405                     }
 406                 case NGM_BRIDGE_SET_CONFIG:
 407                     {
 408                         struct ng_bridge_config *conf;
 409                         int i;
 410
 411                         if (msg->header.arglen
 412                             != sizeof(struct ng_bridge_config)) {
 413                                 error = EINVAL;
 414                                 break;
 415                         }
 416                         conf = (struct ng_bridge_config *)msg->data;
 417                         priv->conf = *conf;
 418                         for (i = 0; i < NG_BRIDGE_MAX_LINKS; i++)
 419                                 priv->conf.ipfw[i] = !!priv->conf.ipfw[i];
 420                         break;
 421                     }
 422                 case NGM_BRIDGE_RESET:
 423                     {
 424                         int i;
 425
 426                         /* Flush all entries in the hash table */
 427                         ng_bridge_remove_hosts(priv, -1);
 428
 429                         /* Reset all loop detection counters and stats */
 430                         for (i = 0; i < NG_BRIDGE_MAX_LINKS; i++) {
 431                                 if (priv->links[i] == NULL)
 432                                         continue;
 433                                 priv->links[i]->loopCount = 0;
 434                                 bzero(&priv->links[i]->stats,
 435                                     sizeof(priv->links[i]->stats));
 436                         }
 437                         break;
 438                     }
 439                 case NGM_BRIDGE_GET_STATS:
 440                 case NGM_BRIDGE_CLR_STATS:
 441                 case NGM_BRIDGE_GETCLR_STATS:
 442                     {
 443                         struct ng_bridge_link *link;
 444                         int linkNum;
 445
 446                         /* Get link number */
 447                         if (msg->header.arglen != sizeof(u_int32_t)) {
 448                                 error = EINVAL;
 449                                 break;
 450                         }
 451                         linkNum = *((u_int32_t *)msg->data);
 452                         if (linkNum < 0 || linkNum >= NG_BRIDGE_MAX_LINKS) {
 453                                 error = EINVAL;
 454                                 break;
 455                         }
 456                         if ((link = priv->links[linkNum]) == NULL) {
 457                                 error = ENOTCONN;
 458                                 break;
 459                         }
 460
 461                         /* Get/clear stats */
 462                         if (msg->header.cmd != NGM_BRIDGE_CLR_STATS) {
 463                                 NG_MKRESPONSE(resp, msg,
 464                                     sizeof(link->stats), M_NOWAIT);
 465                                 if (resp == NULL) {
 466                                         error = ENOMEM;
 467                                         break;
 468                                 }
 469                                 bcopy(&link->stats,
 470                                     resp->data, sizeof(link->stats));
 471                         }
 472                         if (msg->header.cmd != NGM_BRIDGE_GET_STATS)
 473                                 bzero(&link->stats, sizeof(link->stats));
 474                         break;
 475                     }
 476                 case NGM_BRIDGE_GET_TABLE:
 477                     {
 478                         struct ng_bridge_host_ary *ary;
 479                         struct ng_bridge_hent *hent;
 480                         int i = 0, bucket;
 481
 482                         NG_MKRESPONSE(resp, msg, sizeof(*ary)
 483                             + (priv->numHosts * sizeof(*ary->hosts)), M_NOWAIT);
 484                         if (resp == NULL) {
 485                                 error = ENOMEM;
 486                                 break;
 487                         }
 488                         ary = (struct ng_bridge_host_ary *)resp->data;
 489                         ary->numHosts = priv->numHosts;
 490                         for (bucket = 0; bucket < priv->numBuckets; bucket++) {
 491                                 SLIST_FOREACH(hent, &priv->tab[bucket], next)
 492                                         ary->hosts[i++] = hent->host;
 493                         }
 494                         break;
 495                     }
 496                 default:
 497                         error = EINVAL;
 498                         break;
 499                 }
 500                 break;
 501         default:
 502                 error = EINVAL;
 503                 break;
 504         }
 505
 506         /* Done */
 507         if (rptr)
 508                 *rptr = resp;
 509         else if (resp != NULL)
 510                 FREE(resp, M_NETGRAPH);
 511         FREE(msg, M_NETGRAPH);
 512         return (error);
 513 }
 514
 515 /*
 516  * Receive data on a hook
 517  */
 518 static int
 519 ng_bridge_rcvdata(hook_p hook, struct mbuf *m, meta_p meta)
 520 {
 521         const node_p node = hook->node;
 522         const priv_p priv = node->private;
 523         struct ng_bridge_host *host;
 524         struct ng_bridge_link *link;
 525         struct ether_header *eh;
 526         int error = 0, linkNum;
 527         int i, manycast;
 528
 529         /* Get link number */
 530         linkNum = LINK_NUM(hook);
 531         KASSERT(linkNum >= 0 && linkNum < NG_BRIDGE_MAX_LINKS,
 532             ("%s: linkNum=%u", __func__, linkNum));
 533         link = priv->links[linkNum];
 534         KASSERT(link != NULL, ("%s: link%d null", __func__, linkNum));
 535
 536         /* Sanity check packet and pull up header */
 537         if (m->m_pkthdr.len < ETHER_HDR_LEN) {
 538                 link->stats.recvRunts++;
 539                 NG_FREE_DATA(m, meta);
 540                 return (EINVAL);
 541         }
 542         if (m->m_len < ETHER_HDR_LEN && !(m = m_pullup(m, ETHER_HDR_LEN))) {
 543                 link->stats.memoryFailures++;
 544                 NG_FREE_META(meta);
 545                 return (ENOBUFS);
 546         }
 547         eh = mtod(m, struct ether_header *);
 548         if ((eh->ether_shost[0] & 1) != 0) {
 549                 link->stats.recvInvalid++;
 550                 NG_FREE_DATA(m, meta);
 551                 return (EINVAL);
 552         }
 553
 554         /* Is link disabled due to a loopback condition? */
 555         if (link->loopCount != 0) {
 556                 link->stats.loopDrops++;
 557                 NG_FREE_DATA(m, meta);
 558                 return (ELOOP);         /* XXX is this an appropriate error? */
 559         }
 560
 561         /* Update stats */
 562         link->stats.recvPackets++;
 563         link->stats.recvOctets += m->m_pkthdr.len;
 564         if ((manycast = (eh->ether_dhost[0] & 1)) != 0) {
 565                 if (ETHER_EQUAL(eh->ether_dhost, ng_bridge_bcast_addr)) {
 566                         link->stats.recvBroadcasts++;
 567                         manycast = 2;
 568                 } else
 569                         link->stats.recvMulticasts++;
 570         }
 571
 572         /* Look up packet's source Ethernet address in hashtable */
 573         if ((host = ng_bridge_get(priv, eh->ether_shost)) != NULL) {
 574
 575                 /* Update time since last heard from this host */
 576                 host->staleness = 0;
 577
 578                 /* Did host jump to a different link? */
 579                 if (host->linkNum != linkNum) {
 580
 581                         /*
 582                          * If the host's old link was recently established
 583                          * on the old link and it's already jumped to a new
 584                          * link, declare a loopback condition.
 585                          */
 586                         if (host->age < priv->conf.minStableAge) {
 587
 588                                 /* Log the problem */
 589                                 if (priv->conf.debugLevel >= 2) {
 590                                         struct ifnet *ifp = m->m_pkthdr.rcvif;
 591                                         char suffix[32];
 592
 593                                         if (ifp != NULL)
 594                                                 ksnprintf(suffix, sizeof(suffix),
 595                                                     " (%s)", ifp->if_xname);
 596                                         else
 597                                                 *suffix = '\0';
 598                                         log(LOG_WARNING, "ng_bridge: %s:"
 599                                             " loopback detected on %s%s\n",
 600                                             ng_bridge_nodename(node),
 601                                             hook->name, suffix);
 602                                 }
 603
 604                                 /* Mark link as linka non grata */
 605                                 link->loopCount = priv->conf.loopTimeout;
 606                                 link->stats.loopDetects++;
 607
 608                                 /* Forget all hosts on this link */
 609                                 ng_bridge_remove_hosts(priv, linkNum);
 610
 611                                 /* Drop packet */
 612                                 link->stats.loopDrops++;
 613                                 NG_FREE_DATA(m, meta);
 614                                 return (ELOOP);         /* XXX appropriate? */
 615                         }
 616
 617                         /* Move host over to new link */
 618                         host->linkNum = linkNum;
 619                         host->age = 0;
 620                 }
 621         } else {
 622                 if (!ng_bridge_put(priv, eh->ether_shost, linkNum)) {
 623                         link->stats.memoryFailures++;
 624                         NG_FREE_DATA(m, meta);
 625                         return (ENOMEM);
 626                 }
 627         }
 628
 629         /* Run packet through ipfw processing, if enabled */
 630         if (priv->conf.ipfw[linkNum] && fw_enable && ip_fw_chk_ptr != NULL) {
 631                 /* XXX not implemented yet */
 632         }
 633
 634         /*
 635          * If unicast and destination host known, deliver to host's link,
 636          * unless it is the same link as the packet came in on.
 637          */
 638         if (!manycast) {
 639
 640                 /* Determine packet destination link */
 641                 if ((host = ng_bridge_get(priv, eh->ether_dhost)) != NULL) {
 642                         struct ng_bridge_link *const destLink
 643                             = priv->links[host->linkNum];
 644
 645                         /* If destination same as incoming link, do nothing */
 646                         KASSERT(destLink != NULL,
 647                             ("%s: link%d null", __func__, host->linkNum));
 648                         if (destLink == link) {
 649                                 NG_FREE_DATA(m, meta);
 650                                 return (0);
 651                         }
 652
 653                         /* Deliver packet out the destination link */
 654                         destLink->stats.xmitPackets++;
 655                         destLink->stats.xmitOctets += m->m_pkthdr.len;
 656                         NG_SEND_DATA(error, destLink->hook, m, meta);
 657                         return (error);
 658                 }
 659
 660                 /* Destination host is not known */
 661                 link->stats.recvUnknown++;
 662         }
 663
 664         /* Distribute unknown, multicast, broadcast pkts to all other links */
 665         for (linkNum = i = 0; i < priv->numLinks - 1; linkNum++) {
 666                 struct ng_bridge_link *const destLink = priv->links[linkNum];
 667                 meta_p meta2 = NULL;
 668                 struct mbuf *m2;
 669
 670                 /* Skip incoming link and disconnected links */
 671                 if (destLink == NULL || destLink == link)
 672                         continue;
 673
 674                 /* Copy mbuf and meta info */
 675                 if (++i == priv->numLinks - 1) {                /* last link */
 676                         m2 = m;
 677                         meta2 = meta;
 678                 }  else {
 679                         m2 = m_dup(m, M_NOWAIT);        /* XXX m_copypacket() */
 680                         if (m2 == NULL) {
 681                                 link->stats.memoryFailures++;
 682                                 NG_FREE_DATA(m, meta);
 683                                 return (ENOBUFS);
 684                         }
 685                         if (meta != NULL
 686                             && (meta2 = ng_copy_meta(meta)) == NULL) {
 687                                 link->stats.memoryFailures++;
 688                                 m_freem(m2);
 689                                 NG_FREE_DATA(m, meta);
 690                                 return (ENOMEM);
 691                         }
 692                 }
 693
 694                 /* Update stats */
 695                 destLink->stats.xmitPackets++;
 696                 destLink->stats.xmitOctets += m->m_pkthdr.len;
 697                 switch (manycast) {
 698                 case 0:                                 /* unicast */
 699                         break;
 700                 case 1:                                 /* multicast */
 701                         destLink->stats.xmitMulticasts++;
 702                         break;
 703                 case 2:                                 /* broadcast */
 704                         destLink->stats.xmitBroadcasts++;
 705                         break;
 706                 }
 707
 708                 /* Send packet */
 709                 NG_SEND_DATA(error, destLink->hook, m2, meta2);
 710         }
 711         return (error);
 712 }
 713
 714 /*
 715  * Shutdown node
 716  */
 717 static int
 718 ng_bridge_rmnode(node_p node)
 719 {
 720         const priv_p priv = node->private;
 721
 722         /*
 723          * Shut down everything except the timer. There's no way to
 724          * avoid another possible timeout event (it may have already
 725          * been dequeued), so we can't free the node yet.
 726          */
 727         ng_unname(node);
 728         ng_cutlinks(node);              /* frees all link and host info */
 729         KASSERT(priv->numLinks == 0 && priv->numHosts == 0,
 730             ("%s: numLinks=%d numHosts=%d",
 731             __func__, priv->numLinks, priv->numHosts));
 732         FREE(priv->tab, M_NETGRAPH);
 733
 734         /* NG_INVALID flag is now set so node will be freed at next timeout */
 735         return (0);
 736 }
 737
 738 /*
 739  * Hook disconnection.
 740  */
 741 static int
 742 ng_bridge_disconnect(hook_p hook)
 743 {
 744         const priv_p priv = hook->node->private;
 745         int linkNum;
 746
 747         /* Get link number */
 748         linkNum = LINK_NUM(hook);
 749         KASSERT(linkNum >= 0 && linkNum < NG_BRIDGE_MAX_LINKS,
 750             ("%s: linkNum=%u", __func__, linkNum));
 751
 752         /* Remove all hosts associated with this link */
 753         ng_bridge_remove_hosts(priv, linkNum);
 754
 755         /* Free associated link information */
 756         KASSERT(priv->links[linkNum] != NULL, ("%s: no link", __func__));
 757         FREE(priv->links[linkNum], M_NETGRAPH);
 758         priv->links[linkNum] = NULL;
 759         priv->numLinks--;
 760
 761         /* If no more hooks, go away */
 762         if (hook->node->numhooks == 0)
 763                 ng_rmnode(hook->node);
 764         return (0);
 765 }
 766
 767 /******************************************************************
 768                     HASH TABLE FUNCTIONS
 769 ******************************************************************/
 770
 771 /*
 772  * Hash algorithm
 773  *
 774  * Only hashing bytes 3-6 of the Ethernet address is sufficient and fast.
 775  */
 776 #define HASH(addr,mask)         ( (((const u_int16_t *)(addr))[0]       \
 777                                  ^ ((const u_int16_t *)(addr))[1]       \
 778                                  ^ ((const u_int16_t *)(addr))[2]) & (mask) )
 779
 780 /*
 781  * Find a host entry in the table.
 782  */
 783 static struct ng_bridge_host *
 784 ng_bridge_get(priv_p priv, const u_char *addr)
 785 {
 786         const int bucket = HASH(addr, priv->hashMask);
 787         struct ng_bridge_hent *hent;
 788
 789         SLIST_FOREACH(hent, &priv->tab[bucket], next) {
 790                 if (ETHER_EQUAL(hent->host.addr, addr))
 791                         return (&hent->host);
 792         }
 793         return (NULL);
 794 }
 795
 796 /*
 797  * Add a new host entry to the table. This assumes the host doesn't
 798  * already exist in the table. Returns 1 on success, 0 if there
 799  * was a memory allocation failure.
 800  */
 801 static int
 802 ng_bridge_put(priv_p priv, const u_char *addr, int linkNum)
 803 {
 804         const int bucket = HASH(addr, priv->hashMask);
 805         struct ng_bridge_hent *hent;
 806
 807 #ifdef INVARIANTS
 808         /* Assert that entry does not already exist in hashtable */
 809         SLIST_FOREACH(hent, &priv->tab[bucket], next) {
 810                 KASSERT(!ETHER_EQUAL(hent->host.addr, addr),
 811                     ("%s: entry %6D exists in table", __func__, addr, ":"));
 812         }
 813 #endif
 814
 815         /* Allocate and initialize new hashtable entry */
 816         MALLOC(hent, struct ng_bridge_hent *,
 817             sizeof(*hent), M_NETGRAPH, M_NOWAIT);
 818         if (hent == NULL)
 819                 return (0);
 820         bcopy(addr, hent->host.addr, ETHER_ADDR_LEN);
 821         hent->host.linkNum = linkNum;
 822         hent->host.staleness = 0;
 823         hent->host.age = 0;
 824
 825         /* Add new element to hash bucket */
 826         SLIST_INSERT_HEAD(&priv->tab[bucket], hent, next);
 827         priv->numHosts++;
 828
 829         /* Resize table if necessary */
 830         ng_bridge_rehash(priv);
 831         return (1);
 832 }
 833
 834 /*
 835  * Resize the hash table. We try to maintain the number of buckets
 836  * such that the load factor is in the range 0.25 to 1.0.
 837  *
 838  * If we can't get the new memory then we silently fail. This is OK
 839  * because things will still work and we'll try again soon anyway.
 840  */
 841 static void
 842 ng_bridge_rehash(priv_p priv)
 843 {
 844         struct ng_bridge_bucket *newTab;
 845         int oldBucket, newBucket;
 846         int newNumBuckets;
 847         u_int newMask;
 848
 849         /* Is table too full or too empty? */
 850         if (priv->numHosts > priv->numBuckets
 851             && (priv->numBuckets << 1) <= MAX_BUCKETS)
 852                 newNumBuckets = priv->numBuckets << 1;
 853         else if (priv->numHosts < (priv->numBuckets >> 2)
 854             && (priv->numBuckets >> 2) >= MIN_BUCKETS)
 855                 newNumBuckets = priv->numBuckets >> 2;
 856         else
 857                 return;
 858         newMask = newNumBuckets - 1;
 859
 860         /* Allocate and initialize new table */
 861         MALLOC(newTab, struct ng_bridge_bucket *,
 862             newNumBuckets * sizeof(*newTab), M_NETGRAPH, M_NOWAIT);
 863         if (newTab == NULL)
 864                 return;
 865         bzero(newTab, newNumBuckets * sizeof(*newTab));
 866
 867         /* Move all entries from old table to new table */
 868         for (oldBucket = 0; oldBucket < priv->numBuckets; oldBucket++) {
 869                 struct ng_bridge_bucket *const oldList = &priv->tab[oldBucket];
 870
 871                 while (!SLIST_EMPTY(oldList)) {
 872                         struct ng_bridge_hent *const hent
 873                             = SLIST_FIRST(oldList);
 874
 875                         SLIST_REMOVE_HEAD(oldList, next);
 876                         newBucket = HASH(hent->host.addr, newMask);
 877                         SLIST_INSERT_HEAD(&newTab[newBucket], hent, next);
 878                 }
 879         }
 880
 881         /* Replace old table with new one */
 882         if (priv->conf.debugLevel >= 3) {
 883                 log(LOG_INFO, "ng_bridge: %s: table size %d -> %d\n",
 884                     ng_bridge_nodename(priv->node),
 885                     priv->numBuckets, newNumBuckets);
 886         }
 887         FREE(priv->tab, M_NETGRAPH);
 888         priv->numBuckets = newNumBuckets;
 889         priv->hashMask = newMask;
 890         priv->tab = newTab;
 891         return;
 892 }
 893
 894 /******************************************************************
 895                     MISC FUNCTIONS
 896 ******************************************************************/
 897
 898 /*
 899  * Remove all hosts associated with a specific link from the hashtable.
 900  * If linkNum == -1, then remove all hosts in the table.
 901  */
 902 static void
 903 ng_bridge_remove_hosts(priv_p priv, int linkNum)
 904 {
 905         int bucket;
 906
 907         for (bucket = 0; bucket < priv->numBuckets; bucket++) {
 908                 struct ng_bridge_hent **hptr = &SLIST_FIRST(&priv->tab[bucket]);
 909
 910                 while (*hptr != NULL) {
 911                         struct ng_bridge_hent *const hent = *hptr;
 912
 913                         if (linkNum == -1 || hent->host.linkNum == linkNum) {
 914                                 *hptr = SLIST_NEXT(hent, next);
 915                                 FREE(hent, M_NETGRAPH);
 916                                 priv->numHosts--;
 917                         } else
 918                                 hptr = &SLIST_NEXT(hent, next);
 919                 }
 920         }
 921 }
 922
 923 /*
 924  * Handle our once-per-second timeout event. We do two things:
 925  * we decrement link->loopCount for those links being muted due to
 926  * a detected loopback condition, and we remove any hosts from
 927  * the hashtable whom we haven't heard from in a long while.
 928  *
 929  * If the node has the NG_INVALID flag set, our job is to kill it.
 930  */
 931 static void
 932 ng_bridge_timeout(void *arg)
 933 {
 934         const node_p node = arg;
 935         const priv_p priv = node->private;
 936         int bucket;
 937         int counter = 0;
 938         int linkNum;
 939
 940         /* If node was shut down, this is the final lingering timeout */
 941         crit_enter();
 942         if ((node->flags & NG_INVALID) != 0) {
 943                 FREE(priv, M_NETGRAPH);
 944                 node->private = NULL;
 945                 ng_unref(node);
 946                 crit_exit();
 947                 return;
 948         }
 949
 950         /* Register a new timeout, keeping the existing node reference */
 951         callout_reset(&priv->timer, hz, ng_bridge_timeout, node);
 952
 953         /* Update host time counters and remove stale entries */
 954         for (bucket = 0; bucket < priv->numBuckets; bucket++) {
 955                 struct ng_bridge_hent **hptr = &SLIST_FIRST(&priv->tab[bucket]);
 956
 957                 while (*hptr != NULL) {
 958                         struct ng_bridge_hent *const hent = *hptr;
 959
 960                         /* Make sure host's link really exists */
 961                         KASSERT(priv->links[hent->host.linkNum] != NULL,
 962                             ("%s: host %6D on nonexistent link %d\n",
 963                             __func__, hent->host.addr, ":",
 964                             hent->host.linkNum));
 965
 966                         /* Remove hosts we haven't heard from in a while */
 967                         if (++hent->host.staleness >= priv->conf.maxStaleness) {
 968                                 *hptr = SLIST_NEXT(hent, next);
 969                                 FREE(hent, M_NETGRAPH);
 970                                 priv->numHosts--;
 971                         } else {
 972                                 if (hent->host.age < 0xffff)
 973                                         hent->host.age++;
 974                                 hptr = &SLIST_NEXT(hent, next);
 975                                 counter++;
 976                         }
 977                 }
 978         }
 979         KASSERT(priv->numHosts == counter,
 980             ("%s: hosts: %d != %d", __func__, priv->numHosts, counter));
 981
 982         /* Decrease table size if necessary */
 983         ng_bridge_rehash(priv);
 984
 985         /* Decrease loop counter on muted looped back links */
 986         for (counter = linkNum = 0; linkNum < NG_BRIDGE_MAX_LINKS; linkNum++) {
 987                 struct ng_bridge_link *const link = priv->links[linkNum];
 988
 989                 if (link != NULL) {
 990                         if (link->loopCount != 0) {
 991                                 link->loopCount--;
 992                                 if (link->loopCount == 0
 993                                     && priv->conf.debugLevel >= 2) {
 994                                         log(LOG_INFO, "ng_bridge: %s:"
 995                                             " restoring looped back link%d\n",
 996                                             ng_bridge_nodename(node), linkNum);
 997                                 }
 998                         }
 999                         counter++;
1000                 }
1001         }
1002         KASSERT(priv->numLinks == counter,
1003             ("%s: links: %d != %d", __func__, priv->numLinks, counter));
1004
1005         /* Done */
1006         crit_exit();
1007 }
1008
1009 /*
1010  * Return node's "name", even if it doesn't have one.
1011  */
1012 static const char *
1013 ng_bridge_nodename(node_p node)
1014 {
1015         static char name[NG_NODESIZ];
1016
1017         if (node->name != NULL)
1018                 ksnprintf(name, sizeof(name), "%s", node->name);
1019         else
1020                 ksnprintf(name, sizeof(name), "[%x]", ng_node2ID(node));
1021         return name;
1022 }
1023