sys/netgraph/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  * $FreeBSD$
  40  */
  41
  42 /*
  43  * ng_bridge(4) netgraph node type
  44  *
  45  * The node performs standard intelligent Ethernet bridging over
  46  * each of its connected hooks, or links.  A simple loop detection
  47  * algorithm is included which disables a link for priv->conf.loopTimeout
  48  * seconds when a host is seen to have jumped from one link to
  49  * another within priv->conf.minStableAge seconds.
  50  *
  51  * We keep a hashtable that maps Ethernet addresses to host info,
  52  * which is contained in struct ng_bridge_host's. These structures
  53  * tell us on which link the host may be found. A host's entry will
  54  * expire after priv->conf.maxStaleness seconds.
  55  *
  56  * This node is optimzed for stable networks, where machines jump
  57  * from one port to the other only rarely.
  58  */
  59
  60 #include <sys/param.h>
  61 #include <sys/systm.h>
  62 #include <sys/kernel.h>
  63 #include <sys/malloc.h>
  64 #include <sys/mbuf.h>
  65 #include <sys/errno.h>
  66 #include <sys/syslog.h>
  67 #include <sys/socket.h>
  68 #include <sys/ctype.h>
  69
  70 #include <net/if.h>
  71 #include <net/ethernet.h>
  72
  73 #include <netinet/in.h>
  74 #include <netinet/ip_fw.h>
  75
  76 #include <netgraph/ng_message.h>
  77 #include <netgraph/netgraph.h>
  78 #include <netgraph/ng_parse.h>
  79 #include <netgraph/ng_bridge.h>
  80 #include <netgraph/ng_ether.h>
  81
  82 #ifdef NG_SEPARATE_MALLOC
  83 MALLOC_DEFINE(M_NETGRAPH_BRIDGE, "netgraph_bridge", "netgraph bridge node ");
  84 #else
  85 #define M_NETGRAPH_BRIDGE M_NETGRAPH
  86 #endif
  87
  88 /* Per-link private data */
  89 struct ng_bridge_link {
  90         hook_p                          hook;           /* netgraph hook */
  91         u_int16_t                       loopCount;      /* loop ignore timer */
  92         struct ng_bridge_link_stats     stats;          /* link stats */
  93 };
  94
  95 /* Per-node private data */
  96 struct ng_bridge_private {
  97         struct ng_bridge_bucket *tab;           /* hash table bucket array */
  98         struct ng_bridge_link   *links[NG_BRIDGE_MAX_LINKS];
  99         struct ng_bridge_config conf;           /* node configuration */
 100         node_p                  node;           /* netgraph node */
 101         u_int                   numHosts;       /* num entries in table */
 102         u_int                   numBuckets;     /* num buckets in table */
 103         u_int                   hashMask;       /* numBuckets - 1 */
 104         int                     numLinks;       /* num connected links */
 105         struct callout          timer;          /* one second periodic timer */
 106 };
 107 typedef struct ng_bridge_private *priv_p;
 108
 109 /* Information about a host, stored in a hash table entry */
 110 struct ng_bridge_hent {
 111         struct ng_bridge_host           host;   /* actual host info */
 112         SLIST_ENTRY(ng_bridge_hent)     next;   /* next entry in bucket */
 113 };
 114
 115 /* Hash table bucket declaration */
 116 SLIST_HEAD(ng_bridge_bucket, ng_bridge_hent);
 117
 118 /* Netgraph node methods */
 119 static ng_constructor_t ng_bridge_constructor;
 120 static ng_rcvmsg_t      ng_bridge_rcvmsg;
 121 static ng_shutdown_t    ng_bridge_shutdown;
 122 static ng_newhook_t     ng_bridge_newhook;
 123 static ng_rcvdata_t     ng_bridge_rcvdata;
 124 static ng_disconnect_t  ng_bridge_disconnect;
 125
 126 /* Other internal functions */
 127 static struct   ng_bridge_host *ng_bridge_get(priv_p priv, const u_char *addr);
 128 static int      ng_bridge_put(priv_p priv, const u_char *addr, int linkNum);
 129 static void     ng_bridge_rehash(priv_p priv);
 130 static void     ng_bridge_remove_hosts(priv_p priv, int linkNum);
 131 static void     ng_bridge_timeout(void *arg);
 132 static const    char *ng_bridge_nodename(node_p node);
 133
 134 /* Ethernet broadcast */
 135 static const u_char ng_bridge_bcast_addr[ETHER_ADDR_LEN] =
 136     { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
 137
 138 /* Store each hook's link number in the private field */
 139 #define LINK_NUM(hook)          (*(u_int16_t *)(&(hook)->private))
 140
 141 /* Compare Ethernet addresses using 32 and 16 bit words instead of bytewise */
 142 #define ETHER_EQUAL(a,b)        (((const u_int32_t *)(a))[0] \
 143                                         == ((const u_int32_t *)(b))[0] \
 144                                     && ((const u_int16_t *)(a))[2] \
 145                                         == ((const u_int16_t *)(b))[2])
 146
 147 /* Minimum and maximum number of hash buckets. Must be a power of two. */
 148 #define MIN_BUCKETS             (1 << 5)        /* 32 */
 149 #define MAX_BUCKETS             (1 << 14)       /* 16384 */
 150
 151 /* Configuration default values */
 152 #define DEFAULT_LOOP_TIMEOUT    60
 153 #define DEFAULT_MAX_STALENESS   (15 * 60)       /* same as ARP timeout */
 154 #define DEFAULT_MIN_STABLE_AGE  1
 155
 156 /******************************************************************
 157                     NETGRAPH PARSE TYPES
 158 ******************************************************************/
 159
 160 /*
 161  * How to determine the length of the table returned by NGM_BRIDGE_GET_TABLE
 162  */
 163 static int
 164 ng_bridge_getTableLength(const struct ng_parse_type *type,
 165         const u_char *start, const u_char *buf)
 166 {
 167         const struct ng_bridge_host_ary *const hary
 168             = (const struct ng_bridge_host_ary *)(buf - sizeof(u_int32_t));
 169
 170         return hary->numHosts;
 171 }
 172
 173 /* Parse type for struct ng_bridge_host_ary */
 174 static const struct ng_parse_struct_info ng_bridge_host_type_info
 175         = NG_BRIDGE_HOST_TYPE_INFO(&ng_ether_enaddr_type);
 176 static const struct ng_parse_type ng_bridge_host_type = {
 177         &ng_parse_struct_type,
 178         &ng_bridge_host_type_info
 179 };
 180 static const struct ng_parse_array_info ng_bridge_hary_type_info = {
 181         &ng_bridge_host_type,
 182         ng_bridge_getTableLength
 183 };
 184 static const struct ng_parse_type ng_bridge_hary_type = {
 185         &ng_parse_array_type,
 186         &ng_bridge_hary_type_info
 187 };
 188 static const struct ng_parse_struct_info ng_bridge_host_ary_type_info
 189         = NG_BRIDGE_HOST_ARY_TYPE_INFO(&ng_bridge_hary_type);
 190 static const struct ng_parse_type ng_bridge_host_ary_type = {
 191         &ng_parse_struct_type,
 192         &ng_bridge_host_ary_type_info
 193 };
 194
 195 /* Parse type for struct ng_bridge_config */
 196 static const struct ng_parse_fixedarray_info ng_bridge_ipfwary_type_info = {
 197         &ng_parse_uint8_type,
 198         NG_BRIDGE_MAX_LINKS
 199 };
 200 static const struct ng_parse_type ng_bridge_ipfwary_type = {
 201         &ng_parse_fixedarray_type,
 202         &ng_bridge_ipfwary_type_info
 203 };
 204 static const struct ng_parse_struct_info ng_bridge_config_type_info
 205         = NG_BRIDGE_CONFIG_TYPE_INFO(&ng_bridge_ipfwary_type);
 206 static const struct ng_parse_type ng_bridge_config_type = {
 207         &ng_parse_struct_type,
 208         &ng_bridge_config_type_info
 209 };
 210
 211 /* Parse type for struct ng_bridge_link_stat */
 212 static const struct ng_parse_struct_info
 213         ng_bridge_stats_type_info = NG_BRIDGE_STATS_TYPE_INFO;
 214 static const struct ng_parse_type ng_bridge_stats_type = {
 215         &ng_parse_struct_type,
 216         &ng_bridge_stats_type_info
 217 };
 218
 219 /* List of commands and how to convert arguments to/from ASCII */
 220 static const struct ng_cmdlist ng_bridge_cmdlist[] = {
 221         {
 222           NGM_BRIDGE_COOKIE,
 223           NGM_BRIDGE_SET_CONFIG,
 224           "setconfig",
 225           &ng_bridge_config_type,
 226           NULL
 227         },
 228         {
 229           NGM_BRIDGE_COOKIE,
 230           NGM_BRIDGE_GET_CONFIG,
 231           "getconfig",
 232           NULL,
 233           &ng_bridge_config_type
 234         },
 235         {
 236           NGM_BRIDGE_COOKIE,
 237           NGM_BRIDGE_RESET,
 238           "reset",
 239           NULL,
 240           NULL
 241         },
 242         {
 243           NGM_BRIDGE_COOKIE,
 244           NGM_BRIDGE_GET_STATS,
 245           "getstats",
 246           &ng_parse_uint32_type,
 247           &ng_bridge_stats_type
 248         },
 249         {
 250           NGM_BRIDGE_COOKIE,
 251           NGM_BRIDGE_CLR_STATS,
 252           "clrstats",
 253           &ng_parse_uint32_type,
 254           NULL
 255         },
 256         {
 257           NGM_BRIDGE_COOKIE,
 258           NGM_BRIDGE_GETCLR_STATS,
 259           "getclrstats",
 260           &ng_parse_uint32_type,
 261           &ng_bridge_stats_type
 262         },
 263         {
 264           NGM_BRIDGE_COOKIE,
 265           NGM_BRIDGE_GET_TABLE,
 266           "gettable",
 267           NULL,
 268           &ng_bridge_host_ary_type
 269         },
 270         { 0 }
 271 };
 272
 273 /* Node type descriptor */
 274 static struct ng_type ng_bridge_typestruct = {
 275         NG_ABI_VERSION,
 276         NG_BRIDGE_NODE_TYPE,
 277         NULL,
 278         ng_bridge_constructor,
 279         ng_bridge_rcvmsg,
 280         ng_bridge_shutdown,
 281         ng_bridge_newhook,
 282         NULL,
 283         NULL,
 284         ng_bridge_rcvdata,
 285         ng_bridge_disconnect,
 286         ng_bridge_cmdlist,
 287 };
 288 NETGRAPH_INIT(bridge, &ng_bridge_typestruct);
 289
 290 /* Depend on ng_ether so we can use the Ethernet parse type */
 291 MODULE_DEPEND(ng_bridge, ng_ether, 1, 1, 1);
 292
 293 /******************************************************************
 294                     NETGRAPH NODE METHODS
 295 ******************************************************************/
 296
 297 /*
 298  * Node constructor
 299  */
 300 static int
 301 ng_bridge_constructor(node_p node)
 302 {
 303         priv_p priv;
 304
 305         /* Allocate and initialize private info */
 306         MALLOC(priv, priv_p, sizeof(*priv), M_NETGRAPH_BRIDGE, M_NOWAIT | M_ZERO);
 307         if (priv == NULL)
 308                 return (ENOMEM);
 309         callout_init(&priv->timer, 0);
 310
 311         /* Allocate and initialize hash table, etc. */
 312         MALLOC(priv->tab, struct ng_bridge_bucket *,
 313             MIN_BUCKETS * sizeof(*priv->tab), M_NETGRAPH_BRIDGE, M_NOWAIT | M_ZERO);
 314         if (priv->tab == NULL) {
 315                 FREE(priv, M_NETGRAPH_BRIDGE);
 316                 return (ENOMEM);
 317         }
 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         /*
 326          * This node has all kinds of stuff that could be screwed by SMP.
 327          * Until it gets it's own internal protection, we go through in
 328          * single file. This could hurt a machine bridging beteen two
 329          * GB ethernets so it should be fixed.
 330          * When it's fixed the process SHOULD NOT SLEEP, spinlocks please!
 331          * (and atomic ops )
 332          */
 333         NG_NODE_FORCE_WRITER(node);
 334         NG_NODE_SET_PRIVATE(node, priv);
 335         priv->node = node;
 336
 337         /* Start timer; timer is always running while node is alive */
 338         callout_reset(&priv->timer, hz, ng_bridge_timeout, priv->node);
 339
 340         /* Done */
 341         return (0);
 342 }
 343
 344 /*
 345  * Method for attaching a new hook
 346  */
 347 static  int
 348 ng_bridge_newhook(node_p node, hook_p hook, const char *name)
 349 {
 350         const priv_p priv = NG_NODE_PRIVATE(node);
 351
 352         /* Check for a link hook */
 353         if (strncmp(name, NG_BRIDGE_HOOK_LINK_PREFIX,
 354             strlen(NG_BRIDGE_HOOK_LINK_PREFIX)) == 0) {
 355                 const char *cp;
 356                 char *eptr;
 357                 u_long linkNum;
 358
 359                 cp = name + strlen(NG_BRIDGE_HOOK_LINK_PREFIX);
 360                 if (!isdigit(*cp) || (cp[0] == '0' && cp[1] != '\0'))
 361                         return (EINVAL);
 362                 linkNum = strtoul(cp, &eptr, 10);
 363                 if (*eptr != '\0' || linkNum >= NG_BRIDGE_MAX_LINKS)
 364                         return (EINVAL);
 365                 if (priv->links[linkNum] != NULL)
 366                         return (EISCONN);
 367                 MALLOC(priv->links[linkNum], struct ng_bridge_link *,
 368                     sizeof(*priv->links[linkNum]), M_NETGRAPH_BRIDGE, M_NOWAIT|M_ZERO);
 369                 if (priv->links[linkNum] == NULL)
 370                         return (ENOMEM);
 371                 priv->links[linkNum]->hook = hook;
 372                 NG_HOOK_SET_PRIVATE(hook, (void *)linkNum);
 373                 priv->numLinks++;
 374                 return (0);
 375         }
 376
 377         /* Unknown hook name */
 378         return (EINVAL);
 379 }
 380
 381 /*
 382  * Receive a control message
 383  */
 384 static int
 385 ng_bridge_rcvmsg(node_p node, item_p item, hook_p lasthook)
 386 {
 387         const priv_p priv = NG_NODE_PRIVATE(node);
 388         struct ng_mesg *resp = NULL;
 389         int error = 0;
 390         struct ng_mesg *msg;
 391
 392         NGI_GET_MSG(item, msg);
 393         switch (msg->header.typecookie) {
 394         case NGM_BRIDGE_COOKIE:
 395                 switch (msg->header.cmd) {
 396                 case NGM_BRIDGE_GET_CONFIG:
 397                     {
 398                         struct ng_bridge_config *conf;
 399
 400                         NG_MKRESPONSE(resp, msg,
 401                             sizeof(struct ng_bridge_config), M_NOWAIT);
 402                         if (resp == NULL) {
 403                                 error = ENOMEM;
 404                                 break;
 405                         }
 406                         conf = (struct ng_bridge_config *)resp->data;
 407                         *conf = priv->conf;     /* no sanity checking needed */
 408                         break;
 409                     }
 410                 case NGM_BRIDGE_SET_CONFIG:
 411                     {
 412                         struct ng_bridge_config *conf;
 413                         int i;
 414
 415                         if (msg->header.arglen
 416                             != sizeof(struct ng_bridge_config)) {
 417                                 error = EINVAL;
 418                                 break;
 419                         }
 420                         conf = (struct ng_bridge_config *)msg->data;
 421                         priv->conf = *conf;
 422                         for (i = 0; i < NG_BRIDGE_MAX_LINKS; i++)
 423                                 priv->conf.ipfw[i] = !!priv->conf.ipfw[i];
 424                         break;
 425                     }
 426                 case NGM_BRIDGE_RESET:
 427                     {
 428                         int i;
 429
 430                         /* Flush all entries in the hash table */
 431                         ng_bridge_remove_hosts(priv, -1);
 432
 433                         /* Reset all loop detection counters and stats */
 434                         for (i = 0; i < NG_BRIDGE_MAX_LINKS; i++) {
 435                                 if (priv->links[i] == NULL)
 436                                         continue;
 437                                 priv->links[i]->loopCount = 0;
 438                                 bzero(&priv->links[i]->stats,
 439                                     sizeof(priv->links[i]->stats));
 440                         }
 441                         break;
 442                     }
 443                 case NGM_BRIDGE_GET_STATS:
 444                 case NGM_BRIDGE_CLR_STATS:
 445                 case NGM_BRIDGE_GETCLR_STATS:
 446                     {
 447                         struct ng_bridge_link *link;
 448                         int linkNum;
 449
 450                         /* Get link number */
 451                         if (msg->header.arglen != sizeof(u_int32_t)) {
 452                                 error = EINVAL;
 453                                 break;
 454                         }
 455                         linkNum = *((u_int32_t *)msg->data);
 456                         if (linkNum < 0 || linkNum >= NG_BRIDGE_MAX_LINKS) {
 457                                 error = EINVAL;
 458                                 break;
 459                         }
 460                         if ((link = priv->links[linkNum]) == NULL) {
 461                                 error = ENOTCONN;
 462                                 break;
 463                         }
 464
 465                         /* Get/clear stats */
 466                         if (msg->header.cmd != NGM_BRIDGE_CLR_STATS) {
 467                                 NG_MKRESPONSE(resp, msg,
 468                                     sizeof(link->stats), M_NOWAIT);
 469                                 if (resp == NULL) {
 470                                         error = ENOMEM;
 471                                         break;
 472                                 }
 473                                 bcopy(&link->stats,
 474                                     resp->data, sizeof(link->stats));
 475                         }
 476                         if (msg->header.cmd != NGM_BRIDGE_GET_STATS)
 477                                 bzero(&link->stats, sizeof(link->stats));
 478                         break;
 479                     }
 480                 case NGM_BRIDGE_GET_TABLE:
 481                     {
 482                         struct ng_bridge_host_ary *ary;
 483                         struct ng_bridge_hent *hent;
 484                         int i = 0, bucket;
 485
 486                         NG_MKRESPONSE(resp, msg, sizeof(*ary)
 487                             + (priv->numHosts * sizeof(*ary->hosts)), M_NOWAIT);
 488                         if (resp == NULL) {
 489                                 error = ENOMEM;
 490                                 break;
 491                         }
 492                         ary = (struct ng_bridge_host_ary *)resp->data;
 493                         ary->numHosts = priv->numHosts;
 494                         for (bucket = 0; bucket < priv->numBuckets; bucket++) {
 495                                 SLIST_FOREACH(hent, &priv->tab[bucket], next)
 496                                         ary->hosts[i++] = hent->host;
 497                         }
 498                         break;
 499                     }
 500                 default:
 501                         error = EINVAL;
 502                         break;
 503                 }
 504                 break;
 505         default:
 506                 error = EINVAL;
 507                 break;
 508         }
 509
 510         /* Done */
 511         NG_RESPOND_MSG(error, node, item, resp);
 512         NG_FREE_MSG(msg);
 513         return (error);
 514 }
 515
 516 /*
 517  * Receive data on a hook
 518  */
 519 static int
 520 ng_bridge_rcvdata(hook_p hook, item_p item)
 521 {
 522         const node_p node = NG_HOOK_NODE(hook);
 523         const priv_p priv = NG_NODE_PRIVATE(node);
 524         struct ng_bridge_host *host;
 525         struct ng_bridge_link *link;
 526         struct ether_header *eh;
 527         int error = 0, linkNum;
 528         int manycast;
 529         struct mbuf *m;
 530         meta_p meta;
 531         struct ng_bridge_link *firstLink;
 532
 533         NGI_GET_M(item, m);
 534         /* Get link number */
 535         linkNum = (int)NG_HOOK_PRIVATE(hook);
 536         KASSERT(linkNum >= 0 && linkNum < NG_BRIDGE_MAX_LINKS,
 537             ("%s: linkNum=%u", __func__, linkNum));
 538         link = priv->links[linkNum];
 539         KASSERT(link != NULL, ("%s: link%d null", __func__, linkNum));
 540
 541         /* Sanity check packet and pull up header */
 542         if (m->m_pkthdr.len < ETHER_HDR_LEN) {
 543                 link->stats.recvRunts++;
 544                 NG_FREE_ITEM(item);
 545                 NG_FREE_M(m);
 546                 return (EINVAL);
 547         }
 548         if (m->m_len < ETHER_HDR_LEN && !(m = m_pullup(m, ETHER_HDR_LEN))) {
 549                 link->stats.memoryFailures++;
 550                 NG_FREE_ITEM(item);
 551                 return (ENOBUFS);
 552         }
 553         eh = mtod(m, struct ether_header *);
 554         if ((eh->ether_shost[0] & 1) != 0) {
 555                 link->stats.recvInvalid++;
 556                 NG_FREE_ITEM(item);
 557                 NG_FREE_M(m);
 558                 return (EINVAL);
 559         }
 560
 561         /* Is link disabled due to a loopback condition? */
 562         if (link->loopCount != 0) {
 563                 link->stats.loopDrops++;
 564                 NG_FREE_ITEM(item);
 565                 NG_FREE_M(m);
 566                 return (ELOOP);         /* XXX is this an appropriate error? */
 567         }
 568
 569         /* Update stats */
 570         link->stats.recvPackets++;
 571         link->stats.recvOctets += m->m_pkthdr.len;
 572         if ((manycast = (eh->ether_dhost[0] & 1)) != 0) {
 573                 if (ETHER_EQUAL(eh->ether_dhost, ng_bridge_bcast_addr)) {
 574                         link->stats.recvBroadcasts++;
 575                         manycast = 2;
 576                 } else
 577                         link->stats.recvMulticasts++;
 578         }
 579
 580         /* Look up packet's source Ethernet address in hashtable */
 581         if ((host = ng_bridge_get(priv, eh->ether_shost)) != NULL) {
 582
 583                 /* Update time since last heard from this host */
 584                 host->staleness = 0;
 585
 586                 /* Did host jump to a different link? */
 587                 if (host->linkNum != linkNum) {
 588
 589                         /*
 590                          * If the host's old link was recently established
 591                          * on the old link and it's already jumped to a new
 592                          * link, declare a loopback condition.
 593                          */
 594                         if (host->age < priv->conf.minStableAge) {
 595
 596                                 /* Log the problem */
 597                                 if (priv->conf.debugLevel >= 2) {
 598                                         struct ifnet *ifp = m->m_pkthdr.rcvif;
 599                                         char suffix[32];
 600
 601                                         if (ifp != NULL)
 602                                                 snprintf(suffix, sizeof(suffix),
 603                                                     " (%s%d)", ifp->if_name,
 604                                                     ifp->if_unit);
 605                                         else
 606                                                 *suffix = '\0';
 607                                         log(LOG_WARNING, "ng_bridge: %s:"
 608                                             " loopback detected on %s%s\n",
 609                                             ng_bridge_nodename(node),
 610                                             NG_HOOK_NAME(hook), suffix);
 611                                 }
 612
 613                                 /* Mark link as linka non grata */
 614                                 link->loopCount = priv->conf.loopTimeout;
 615                                 link->stats.loopDetects++;
 616
 617                                 /* Forget all hosts on this link */
 618                                 ng_bridge_remove_hosts(priv, linkNum);
 619
 620                                 /* Drop packet */
 621                                 link->stats.loopDrops++;
 622                                 NG_FREE_ITEM(item);
 623                                 NG_FREE_M(m);
 624                                 return (ELOOP);         /* XXX appropriate? */
 625                         }
 626
 627                         /* Move host over to new link */
 628                         host->linkNum = linkNum;
 629                         host->age = 0;
 630                 }
 631         } else {
 632                 if (!ng_bridge_put(priv, eh->ether_shost, linkNum)) {
 633                         link->stats.memoryFailures++;
 634                         NG_FREE_ITEM(item);
 635                         NG_FREE_M(m);
 636                         return (ENOMEM);
 637                 }
 638         }
 639
 640         /* Run packet through ipfw processing, if enabled */
 641         if (priv->conf.ipfw[linkNum] && fw_enable && ip_fw_chk_ptr != NULL) {
 642                 /* XXX not implemented yet */
 643         }
 644
 645         /*
 646          * If unicast and destination host known, deliver to host's link,
 647          * unless it is the same link as the packet came in on.
 648          */
 649         if (!manycast) {
 650
 651                 /* Determine packet destination link */
 652                 if ((host = ng_bridge_get(priv, eh->ether_dhost)) != NULL) {
 653                         struct ng_bridge_link *const destLink
 654                             = priv->links[host->linkNum];
 655
 656                         /* If destination same as incoming link, do nothing */
 657                         KASSERT(destLink != NULL,
 658                             ("%s: link%d null", __func__, host->linkNum));
 659                         if (destLink == link) {
 660                                 NG_FREE_ITEM(item);
 661                                 NG_FREE_M(m);
 662                                 return (0);
 663                         }
 664
 665                         /* Deliver packet out the destination link */
 666                         destLink->stats.xmitPackets++;
 667                         destLink->stats.xmitOctets += m->m_pkthdr.len;
 668                         NG_FWD_NEW_DATA(error, item, destLink->hook, m);
 669                         return (error);
 670                 }
 671
 672                 /* Destination host is not known */
 673                 link->stats.recvUnknown++;
 674         }
 675
 676         /* Distribute unknown, multicast, broadcast pkts to all other links */
 677         meta = NGI_META(item); /* peek.. */
 678         firstLink = NULL;
 679         for (linkNum = 0; linkNum <= priv->numLinks; linkNum++) {
 680                 struct ng_bridge_link *destLink;
 681                 meta_p meta2 = NULL;
 682                 struct mbuf *m2 = NULL;
 683
 684                 /*
 685                  * If we have checked all the links then now
 686                  * send the original on its reserved link
 687                  */
 688                 if (linkNum == priv->numLinks) {
 689                         /* If we never saw a good link, leave. */
 690                         if (firstLink == NULL) {
 691                                 NG_FREE_ITEM(item);
 692                                 NG_FREE_M(m);
 693                                 return (0);
 694                         }
 695                         destLink = firstLink;
 696                 } else {
 697                         destLink = priv->links[linkNum];
 698                         /* Skip incoming link and disconnected links */
 699                         if (destLink == NULL || destLink == link) {
 700                                 continue;
 701                         }
 702                         if (firstLink == NULL) {
 703                                 /*
 704                                  * This is the first usable link we have found.
 705                                  * Reserve it for the originals.
 706                                  * If we never find another we save a copy.
 707                                  */
 708                                 firstLink = destLink;
 709                                 continue;
 710                         }
 711
 712                         /*
 713                          * It's usable link but not the reserved (first) one.
 714                          * Copy mbuf and meta info for sending.
 715                          */
 716                         m2 = m_dup(m, M_NOWAIT);        /* XXX m_copypacket() */
 717                         if (m2 == NULL) {
 718                                 link->stats.memoryFailures++;
 719                                 NG_FREE_ITEM(item);
 720                                 NG_FREE_M(m);
 721                                 return (ENOBUFS);
 722                         }
 723                         if (meta != NULL
 724                             && (meta2 = ng_copy_meta(meta)) == NULL) {
 725                                 link->stats.memoryFailures++;
 726                                 m_freem(m2);
 727                                 NG_FREE_ITEM(item);
 728                                 NG_FREE_M(m);
 729                                 return (ENOMEM);
 730                         }
 731                 }
 732
 733                 /* Update stats */
 734                 destLink->stats.xmitPackets++;
 735                 destLink->stats.xmitOctets += m->m_pkthdr.len;
 736                 switch (manycast) {
 737                 case 0:                                 /* unicast */
 738                         break;
 739                 case 1:                                 /* multicast */
 740                         destLink->stats.xmitMulticasts++;
 741                         break;
 742                 case 2:                                 /* broadcast */
 743                         destLink->stats.xmitBroadcasts++;
 744                         break;
 745                 }
 746
 747                 /* Send packet */
 748                 if (destLink == firstLink) {
 749                         /*
 750                          * If we've sent all the others, send the original
 751                          * on the first link we found.
 752                          */
 753                         NG_FWD_NEW_DATA(error, item, destLink->hook, m);
 754                         break; /* always done last - not really needed. */
 755                 } else {
 756                         NG_SEND_DATA(error, destLink->hook, m2, meta2);
 757                 }
 758         }
 759         return (error);
 760 }
 761
 762 /*
 763  * Shutdown node
 764  */
 765 static int
 766 ng_bridge_shutdown(node_p node)
 767 {
 768         const priv_p priv = NG_NODE_PRIVATE(node);
 769
 770         /*
 771          * Shut down everything except the timer. There's no way to
 772          * avoid another possible timeout event (it may have already
 773          * been dequeued), so we can't free the node yet.
 774          */
 775         KASSERT(priv->numLinks == 0 && priv->numHosts == 0,
 776             ("%s: numLinks=%d numHosts=%d",
 777             __func__, priv->numLinks, priv->numHosts));
 778         FREE(priv->tab, M_NETGRAPH_BRIDGE);
 779
 780         /* NG_INVALID flag is now set so node will be freed at next timeout */
 781         return (0);
 782 }
 783
 784 /*
 785  * Hook disconnection.
 786  */
 787 static int
 788 ng_bridge_disconnect(hook_p hook)
 789 {
 790         const priv_p priv = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
 791         int linkNum;
 792
 793         /* Get link number */
 794         linkNum = (int)NG_HOOK_PRIVATE(hook);
 795         KASSERT(linkNum >= 0 && linkNum < NG_BRIDGE_MAX_LINKS,
 796             ("%s: linkNum=%u", __func__, linkNum));
 797
 798         /* Remove all hosts associated with this link */
 799         ng_bridge_remove_hosts(priv, linkNum);
 800
 801         /* Free associated link information */
 802         KASSERT(priv->links[linkNum] != NULL, ("%s: no link", __func__));
 803         FREE(priv->links[linkNum], M_NETGRAPH_BRIDGE);
 804         priv->links[linkNum] = NULL;
 805         priv->numLinks--;
 806
 807         /* If no more hooks, go away */
 808         if ((NG_NODE_NUMHOOKS(NG_HOOK_NODE(hook)) == 0)
 809         && (NG_NODE_IS_VALID(NG_HOOK_NODE(hook)))) {
 810                 ng_rmnode_self(NG_HOOK_NODE(hook));
 811         }
 812         return (0);
 813 }
 814
 815 /******************************************************************
 816                     HASH TABLE FUNCTIONS
 817 ******************************************************************/
 818
 819 /*
 820  * Hash algorithm
 821  *
 822  * Only hashing bytes 3-6 of the Ethernet address is sufficient and fast.
 823  */
 824 #define HASH(addr,mask)         ( (((const u_int16_t *)(addr))[0]       \
 825                                  ^ ((const u_int16_t *)(addr))[1]       \
 826                                  ^ ((const u_int16_t *)(addr))[2]) & (mask) )
 827
 828 /*
 829  * Find a host entry in the table.
 830  */
 831 static struct ng_bridge_host *
 832 ng_bridge_get(priv_p priv, const u_char *addr)
 833 {
 834         const int bucket = HASH(addr, priv->hashMask);
 835         struct ng_bridge_hent *hent;
 836
 837         SLIST_FOREACH(hent, &priv->tab[bucket], next) {
 838                 if (ETHER_EQUAL(hent->host.addr, addr))
 839                         return (&hent->host);
 840         }
 841         return (NULL);
 842 }
 843
 844 /*
 845  * Add a new host entry to the table. This assumes the host doesn't
 846  * already exist in the table. Returns 1 on success, 0 if there
 847  * was a memory allocation failure.
 848  */
 849 static int
 850 ng_bridge_put(priv_p priv, const u_char *addr, int linkNum)
 851 {
 852         const int bucket = HASH(addr, priv->hashMask);
 853         struct ng_bridge_hent *hent;
 854
 855 #ifdef INVARIANTS
 856         /* Assert that entry does not already exist in hashtable */
 857         SLIST_FOREACH(hent, &priv->tab[bucket], next) {
 858                 KASSERT(!ETHER_EQUAL(hent->host.addr, addr),
 859                     ("%s: entry %6D exists in table", __func__, addr, ":"));
 860         }
 861 #endif
 862
 863         /* Allocate and initialize new hashtable entry */
 864         MALLOC(hent, struct ng_bridge_hent *,
 865             sizeof(*hent), M_NETGRAPH_BRIDGE, M_NOWAIT);
 866         if (hent == NULL)
 867                 return (0);
 868         bcopy(addr, hent->host.addr, ETHER_ADDR_LEN);
 869         hent->host.linkNum = linkNum;
 870         hent->host.staleness = 0;
 871         hent->host.age = 0;
 872
 873         /* Add new element to hash bucket */
 874         SLIST_INSERT_HEAD(&priv->tab[bucket], hent, next);
 875         priv->numHosts++;
 876
 877         /* Resize table if necessary */
 878         ng_bridge_rehash(priv);
 879         return (1);
 880 }
 881
 882 /*
 883  * Resize the hash table. We try to maintain the number of buckets
 884  * such that the load factor is in the range 0.25 to 1.0.
 885  *
 886  * If we can't get the new memory then we silently fail. This is OK
 887  * because things will still work and we'll try again soon anyway.
 888  */
 889 static void
 890 ng_bridge_rehash(priv_p priv)
 891 {
 892         struct ng_bridge_bucket *newTab;
 893         int oldBucket, newBucket;
 894         int newNumBuckets;
 895         u_int newMask;
 896
 897         /* Is table too full or too empty? */
 898         if (priv->numHosts > priv->numBuckets
 899             && (priv->numBuckets << 1) <= MAX_BUCKETS)
 900                 newNumBuckets = priv->numBuckets << 1;
 901         else if (priv->numHosts < (priv->numBuckets >> 2)
 902             && (priv->numBuckets >> 2) >= MIN_BUCKETS)
 903                 newNumBuckets = priv->numBuckets >> 2;
 904         else
 905                 return;
 906         newMask = newNumBuckets - 1;
 907
 908         /* Allocate and initialize new table */
 909         MALLOC(newTab, struct ng_bridge_bucket *,
 910             newNumBuckets * sizeof(*newTab), M_NETGRAPH_BRIDGE, M_NOWAIT | M_ZERO);
 911         if (newTab == NULL)
 912                 return;
 913
 914         /* Move all entries from old table to new table */
 915         for (oldBucket = 0; oldBucket < priv->numBuckets; oldBucket++) {
 916                 struct ng_bridge_bucket *const oldList = &priv->tab[oldBucket];
 917
 918                 while (!SLIST_EMPTY(oldList)) {
 919                         struct ng_bridge_hent *const hent
 920                             = SLIST_FIRST(oldList);
 921
 922                         SLIST_REMOVE_HEAD(oldList, next);
 923                         newBucket = HASH(hent->host.addr, newMask);
 924                         SLIST_INSERT_HEAD(&newTab[newBucket], hent, next);
 925                 }
 926         }
 927
 928         /* Replace old table with new one */
 929         if (priv->conf.debugLevel >= 3) {
 930                 log(LOG_INFO, "ng_bridge: %s: table size %d -> %d\n",
 931                     ng_bridge_nodename(priv->node),
 932                     priv->numBuckets, newNumBuckets);
 933         }
 934         FREE(priv->tab, M_NETGRAPH_BRIDGE);
 935         priv->numBuckets = newNumBuckets;
 936         priv->hashMask = newMask;
 937         priv->tab = newTab;
 938         return;
 939 }
 940
 941 /******************************************************************
 942                     MISC FUNCTIONS
 943 ******************************************************************/
 944
 945 /*
 946  * Remove all hosts associated with a specific link from the hashtable.
 947  * If linkNum == -1, then remove all hosts in the table.
 948  */
 949 static void
 950 ng_bridge_remove_hosts(priv_p priv, int linkNum)
 951 {
 952         int bucket;
 953
 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                         if (linkNum == -1 || hent->host.linkNum == linkNum) {
 961                                 *hptr = SLIST_NEXT(hent, next);
 962                                 FREE(hent, M_NETGRAPH_BRIDGE);
 963                                 priv->numHosts--;
 964                         } else
 965                                 hptr = &SLIST_NEXT(hent, next);
 966                 }
 967         }
 968 }
 969
 970 /*
 971  * Handle our once-per-second timeout event. We do two things:
 972  * we decrement link->loopCount for those links being muted due to
 973  * a detected loopback condition, and we remove any hosts from
 974  * the hashtable whom we haven't heard from in a long while.
 975  *
 976  * If the node has the NG_INVALID flag set, our job is to kill it.
 977  */
 978 static void
 979 ng_bridge_timeout(void *arg)
 980 {
 981         const node_p node = arg;
 982         const priv_p priv = NG_NODE_PRIVATE(node);
 983         int s, bucket;
 984         int counter = 0;
 985         int linkNum;
 986
 987         /* If node was shut down, this is the final lingering timeout */
 988         s = splnet();
 989         if (NG_NODE_NOT_VALID(node)) {
 990                 FREE(priv, M_NETGRAPH);
 991                 NG_NODE_SET_PRIVATE(node, NULL);
 992                 NG_NODE_UNREF(node);
 993                 splx(s);
 994                 return;
 995         }
 996
 997         /* Register a new timeout, keeping the existing node reference */
 998         callout_reset(&priv->timer, hz, ng_bridge_timeout, node);
 999
1000         /* Update host time counters and remove stale entries */
1001         for (bucket = 0; bucket < priv->numBuckets; bucket++) {
1002                 struct ng_bridge_hent **hptr = &SLIST_FIRST(&priv->tab[bucket]);
1003
1004                 while (*hptr != NULL) {
1005                         struct ng_bridge_hent *const hent = *hptr;
1006
1007                         /* Make sure host's link really exists */
1008                         KASSERT(priv->links[hent->host.linkNum] != NULL,
1009                             ("%s: host %6D on nonexistent link %d\n",
1010                             __func__, hent->host.addr, ":",
1011                             hent->host.linkNum));
1012
1013                         /* Remove hosts we haven't heard from in a while */
1014                         if (++hent->host.staleness >= priv->conf.maxStaleness) {
1015                                 *hptr = SLIST_NEXT(hent, next);
1016                                 FREE(hent, M_NETGRAPH_BRIDGE);
1017                                 priv->numHosts--;
1018                         } else {
1019                                 if (hent->host.age < 0xffff)
1020                                         hent->host.age++;
1021                                 hptr = &SLIST_NEXT(hent, next);
1022                                 counter++;
1023                         }
1024                 }
1025         }
1026         KASSERT(priv->numHosts == counter,
1027             ("%s: hosts: %d != %d", __func__, priv->numHosts, counter));
1028
1029         /* Decrease table size if necessary */
1030         ng_bridge_rehash(priv);
1031
1032         /* Decrease loop counter on muted looped back links */
1033         for (counter = linkNum = 0; linkNum < NG_BRIDGE_MAX_LINKS; linkNum++) {
1034                 struct ng_bridge_link *const link = priv->links[linkNum];
1035
1036                 if (link != NULL) {
1037                         if (link->loopCount != 0) {
1038                                 link->loopCount--;
1039                                 if (link->loopCount == 0
1040                                     && priv->conf.debugLevel >= 2) {
1041                                         log(LOG_INFO, "ng_bridge: %s:"
1042                                             " restoring looped back link%d\n",
1043                                             ng_bridge_nodename(node), linkNum);
1044                                 }
1045                         }
1046                         counter++;
1047                 }
1048         }
1049         KASSERT(priv->numLinks == counter,
1050             ("%s: links: %d != %d", __func__, priv->numLinks, counter));
1051
1052         /* Done */
1053         splx(s);
1054 }
1055
1056 /*
1057  * Return node's "name", even if it doesn't have one.
1058  */
1059 static const char *
1060 ng_bridge_nodename(node_p node)
1061 {
1062         static char name[NG_NODELEN+1];
1063
1064         if (NG_NODE_NAME(node) != NULL)
1065                 snprintf(name, sizeof(name), "%s", NG_NODE_NAME(node));
1066         else
1067                 snprintf(name, sizeof(name), "[%x]", ng_node2ID(node));
1068         return name;
1069 }
1070