sys/netgraph/ng_bridge.c

   1 /*
   2  * ng_bridge.c
   3  */
   4
   5 /*-
   6  * Copyright (c) 2000 Whistle Communications, Inc.
   7  * All rights reserved.
   8  *
   9  * Subject to the following obligations and disclaimer of warranty, use and
  10  * redistribution of this software, in source or object code forms, with or
  11  * without modifications are expressly permitted by Whistle Communications;
  12  * provided, however, that:
  13  * 1. Any and all reproductions of the source or object code must include the
  14  *    copyright notice above and the following disclaimer of warranties; and
  15  * 2. No rights are granted, in any manner or form, to use Whistle
  16  *    Communications, Inc. trademarks, including the mark "WHISTLE
  17  *    COMMUNICATIONS" on advertising, endorsements, or otherwise except as
  18  *    such appears in the above copyright notice or in the software.
  19  *
  20  * THIS SOFTWARE IS BEING PROVIDED BY WHISTLE COMMUNICATIONS "AS IS", AND
  21  * TO THE MAXIMUM EXTENT PERMITTED BY LAW, WHISTLE COMMUNICATIONS MAKES NO
  22  * REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED, REGARDING THIS SOFTWARE,
  23  * INCLUDING WITHOUT LIMITATION, ANY AND ALL IMPLIED WARRANTIES OF
  24  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT.
  25  * WHISTLE COMMUNICATIONS DOES NOT WARRANT, GUARANTEE, OR MAKE ANY
  26  * REPRESENTATIONS REGARDING THE USE OF, OR THE RESULTS OF THE USE OF THIS
  27  * SOFTWARE IN TERMS OF ITS CORRECTNESS, ACCURACY, RELIABILITY OR OTHERWISE.
  28  * IN NO EVENT SHALL WHISTLE COMMUNICATIONS BE LIABLE FOR ANY DAMAGES
  29  * RESULTING FROM OR ARISING OUT OF ANY USE OF THIS SOFTWARE, INCLUDING
  30  * WITHOUT LIMITATION, ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
  31  * PUNITIVE, OR CONSEQUENTIAL DAMAGES, PROCUREMENT OF SUBSTITUTE GOODS OR
  32  * SERVICES, LOSS OF USE, DATA OR PROFITS, HOWEVER CAUSED AND UNDER ANY
  33  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  34  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  35  * THIS SOFTWARE, EVEN IF WHISTLE COMMUNICATIONS IS ADVISED OF THE POSSIBILITY
  36  * OF SUCH DAMAGE.
  37  *
  38  * Author: Archie Cobbs <archie@freebsd.org>
  39  *
  40  * $FreeBSD$
  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/lock.h>
  65 #include <sys/malloc.h>
  66 #include <sys/mbuf.h>
  67 #include <sys/errno.h>
  68 #include <sys/rwlock.h>
  69 #include <sys/syslog.h>
  70 #include <sys/socket.h>
  71 #include <sys/ctype.h>
  72
  73 #include <net/if.h>
  74 #include <net/ethernet.h>
  75 #include <net/vnet.h>
  76
  77 #include <netinet/in.h>
  78 #if 0   /* not used yet */
  79 #include <netinet/ip_fw.h>
  80 #endif
  81 #include <netgraph/ng_message.h>
  82 #include <netgraph/netgraph.h>
  83 #include <netgraph/ng_parse.h>
  84 #include <netgraph/ng_bridge.h>
  85
  86 #ifdef NG_SEPARATE_MALLOC
  87 static MALLOC_DEFINE(M_NETGRAPH_BRIDGE, "netgraph_bridge",
  88     "netgraph bridge node");
  89 #else
  90 #define M_NETGRAPH_BRIDGE M_NETGRAPH
  91 #endif
  92
  93 /* Per-link private data */
  94 struct ng_bridge_link {
  95         hook_p                          hook;           /* netgraph hook */
  96         u_int16_t                       loopCount;      /* loop ignore timer */
  97         struct ng_bridge_link_stats     stats;          /* link stats */
  98 };
  99
 100 /* Per-node private data */
 101 struct ng_bridge_private {
 102         struct ng_bridge_bucket *tab;           /* hash table bucket array */
 103         struct ng_bridge_link   *links[NG_BRIDGE_MAX_LINKS];
 104         struct ng_bridge_config conf;           /* node configuration */
 105         node_p                  node;           /* netgraph node */
 106         u_int                   numHosts;       /* num entries in table */
 107         u_int                   numBuckets;     /* num buckets in table */
 108         u_int                   hashMask;       /* numBuckets - 1 */
 109         int                     numLinks;       /* num connected links */
 110         int                     persistent;     /* can exist w/o hooks */
 111         struct callout          timer;          /* one second periodic timer */
 112 };
 113 typedef struct ng_bridge_private *priv_p;
 114
 115 /* Information about a host, stored in a hash table entry */
 116 struct ng_bridge_hent {
 117         struct ng_bridge_host           host;   /* actual host info */
 118         SLIST_ENTRY(ng_bridge_hent)     next;   /* next entry in bucket */
 119 };
 120
 121 /* Hash table bucket declaration */
 122 SLIST_HEAD(ng_bridge_bucket, ng_bridge_hent);
 123
 124 /* Netgraph node methods */
 125 static ng_constructor_t ng_bridge_constructor;
 126 static ng_rcvmsg_t      ng_bridge_rcvmsg;
 127 static ng_shutdown_t    ng_bridge_shutdown;
 128 static ng_newhook_t     ng_bridge_newhook;
 129 static ng_rcvdata_t     ng_bridge_rcvdata;
 130 static ng_disconnect_t  ng_bridge_disconnect;
 131
 132 /* Other internal functions */
 133 static struct   ng_bridge_host *ng_bridge_get(priv_p priv, const u_char *addr);
 134 static int      ng_bridge_put(priv_p priv, const u_char *addr, int linkNum);
 135 static void     ng_bridge_rehash(priv_p priv);
 136 static void     ng_bridge_remove_hosts(priv_p priv, int linkNum);
 137 static void     ng_bridge_timeout(node_p node, hook_p hook, void *arg1, int arg2);
 138 static const    char *ng_bridge_nodename(node_p node);
 139
 140 /* Ethernet broadcast */
 141 static const u_char ng_bridge_bcast_addr[ETHER_ADDR_LEN] =
 142     { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
 143
 144 /* Store each hook's link number in the private field */
 145 #define LINK_NUM(hook)          (*(u_int16_t *)(&(hook)->private))
 146
 147 /* Compare Ethernet addresses using 32 and 16 bit words instead of bytewise */
 148 #define ETHER_EQUAL(a,b)        (((const u_int32_t *)(a))[0] \
 149                                         == ((const u_int32_t *)(b))[0] \
 150                                     && ((const u_int16_t *)(a))[2] \
 151                                         == ((const u_int16_t *)(b))[2])
 152
 153 /* Minimum and maximum number of hash buckets. Must be a power of two. */
 154 #define MIN_BUCKETS             (1 << 5)        /* 32 */
 155 #define MAX_BUCKETS             (1 << 14)       /* 16384 */
 156
 157 /* Configuration default values */
 158 #define DEFAULT_LOOP_TIMEOUT    60
 159 #define DEFAULT_MAX_STALENESS   (15 * 60)       /* same as ARP timeout */
 160 #define DEFAULT_MIN_STABLE_AGE  1
 161
 162 /******************************************************************
 163                     NETGRAPH PARSE TYPES
 164 ******************************************************************/
 165
 166 /*
 167  * How to determine the length of the table returned by NGM_BRIDGE_GET_TABLE
 168  */
 169 static int
 170 ng_bridge_getTableLength(const struct ng_parse_type *type,
 171         const u_char *start, const u_char *buf)
 172 {
 173         const struct ng_bridge_host_ary *const hary
 174             = (const struct ng_bridge_host_ary *)(buf - sizeof(u_int32_t));
 175
 176         return hary->numHosts;
 177 }
 178
 179 /* Parse type for struct ng_bridge_host_ary */
 180 static const struct ng_parse_struct_field ng_bridge_host_type_fields[]
 181         = NG_BRIDGE_HOST_TYPE_INFO(&ng_parse_enaddr_type);
 182 static const struct ng_parse_type ng_bridge_host_type = {
 183         &ng_parse_struct_type,
 184         &ng_bridge_host_type_fields
 185 };
 186 static const struct ng_parse_array_info ng_bridge_hary_type_info = {
 187         &ng_bridge_host_type,
 188         ng_bridge_getTableLength
 189 };
 190 static const struct ng_parse_type ng_bridge_hary_type = {
 191         &ng_parse_array_type,
 192         &ng_bridge_hary_type_info
 193 };
 194 static const struct ng_parse_struct_field ng_bridge_host_ary_type_fields[]
 195         = NG_BRIDGE_HOST_ARY_TYPE_INFO(&ng_bridge_hary_type);
 196 static const struct ng_parse_type ng_bridge_host_ary_type = {
 197         &ng_parse_struct_type,
 198         &ng_bridge_host_ary_type_fields
 199 };
 200
 201 /* Parse type for struct ng_bridge_config */
 202 static const struct ng_parse_fixedarray_info ng_bridge_ipfwary_type_info = {
 203         &ng_parse_uint8_type,
 204         NG_BRIDGE_MAX_LINKS
 205 };
 206 static const struct ng_parse_type ng_bridge_ipfwary_type = {
 207         &ng_parse_fixedarray_type,
 208         &ng_bridge_ipfwary_type_info
 209 };
 210 static const struct ng_parse_struct_field ng_bridge_config_type_fields[]
 211         = NG_BRIDGE_CONFIG_TYPE_INFO(&ng_bridge_ipfwary_type);
 212 static const struct ng_parse_type ng_bridge_config_type = {
 213         &ng_parse_struct_type,
 214         &ng_bridge_config_type_fields
 215 };
 216
 217 /* Parse type for struct ng_bridge_link_stat */
 218 static const struct ng_parse_struct_field ng_bridge_stats_type_fields[]
 219         = NG_BRIDGE_STATS_TYPE_INFO;
 220 static const struct ng_parse_type ng_bridge_stats_type = {
 221         &ng_parse_struct_type,
 222         &ng_bridge_stats_type_fields
 223 };
 224
 225 /* List of commands and how to convert arguments to/from ASCII */
 226 static const struct ng_cmdlist ng_bridge_cmdlist[] = {
 227         {
 228           NGM_BRIDGE_COOKIE,
 229           NGM_BRIDGE_SET_CONFIG,
 230           "setconfig",
 231           &ng_bridge_config_type,
 232           NULL
 233         },
 234         {
 235           NGM_BRIDGE_COOKIE,
 236           NGM_BRIDGE_GET_CONFIG,
 237           "getconfig",
 238           NULL,
 239           &ng_bridge_config_type
 240         },
 241         {
 242           NGM_BRIDGE_COOKIE,
 243           NGM_BRIDGE_RESET,
 244           "reset",
 245           NULL,
 246           NULL
 247         },
 248         {
 249           NGM_BRIDGE_COOKIE,
 250           NGM_BRIDGE_GET_STATS,
 251           "getstats",
 252           &ng_parse_uint32_type,
 253           &ng_bridge_stats_type
 254         },
 255         {
 256           NGM_BRIDGE_COOKIE,
 257           NGM_BRIDGE_CLR_STATS,
 258           "clrstats",
 259           &ng_parse_uint32_type,
 260           NULL
 261         },
 262         {
 263           NGM_BRIDGE_COOKIE,
 264           NGM_BRIDGE_GETCLR_STATS,
 265           "getclrstats",
 266           &ng_parse_uint32_type,
 267           &ng_bridge_stats_type
 268         },
 269         {
 270           NGM_BRIDGE_COOKIE,
 271           NGM_BRIDGE_GET_TABLE,
 272           "gettable",
 273           NULL,
 274           &ng_bridge_host_ary_type
 275         },
 276         {
 277           NGM_BRIDGE_COOKIE,
 278           NGM_BRIDGE_SET_PERSISTENT,
 279           "setpersistent",
 280           NULL,
 281           NULL
 282         },
 283         { 0 }
 284 };
 285
 286 /* Node type descriptor */
 287 static struct ng_type ng_bridge_typestruct = {
 288         .version =      NG_ABI_VERSION,
 289         .name =         NG_BRIDGE_NODE_TYPE,
 290         .constructor =  ng_bridge_constructor,
 291         .rcvmsg =       ng_bridge_rcvmsg,
 292         .shutdown =     ng_bridge_shutdown,
 293         .newhook =      ng_bridge_newhook,
 294         .rcvdata =      ng_bridge_rcvdata,
 295         .disconnect =   ng_bridge_disconnect,
 296         .cmdlist =      ng_bridge_cmdlist,
 297 };
 298 NETGRAPH_INIT(bridge, &ng_bridge_typestruct);
 299
 300 /******************************************************************
 301                     NETGRAPH NODE METHODS
 302 ******************************************************************/
 303
 304 /*
 305  * Node constructor
 306  */
 307 static int
 308 ng_bridge_constructor(node_p node)
 309 {
 310         priv_p priv;
 311
 312         /* Allocate and initialize private info */
 313         priv = malloc(sizeof(*priv), M_NETGRAPH_BRIDGE, M_WAITOK | M_ZERO);
 314         ng_callout_init(&priv->timer);
 315
 316         /* Allocate and initialize hash table, etc. */
 317         priv->tab = malloc(MIN_BUCKETS * sizeof(*priv->tab),
 318             M_NETGRAPH_BRIDGE, M_WAITOK | M_ZERO);
 319         priv->numBuckets = MIN_BUCKETS;
 320         priv->hashMask = MIN_BUCKETS - 1;
 321         priv->conf.debugLevel = 1;
 322         priv->conf.loopTimeout = DEFAULT_LOOP_TIMEOUT;
 323         priv->conf.maxStaleness = DEFAULT_MAX_STALENESS;
 324         priv->conf.minStableAge = DEFAULT_MIN_STABLE_AGE;
 325
 326         /*
 327          * This node has all kinds of stuff that could be screwed by SMP.
 328          * Until it gets it's own internal protection, we go through in
 329          * single file. This could hurt a machine bridging beteen two
 330          * GB ethernets so it should be fixed.
 331          * When it's fixed the process SHOULD NOT SLEEP, spinlocks please!
 332          * (and atomic ops )
 333          */
 334         NG_NODE_FORCE_WRITER(node);
 335         NG_NODE_SET_PRIVATE(node, priv);
 336         priv->node = node;
 337
 338         /* Start timer; timer is always running while node is alive */
 339         ng_callout(&priv->timer, node, NULL, hz, ng_bridge_timeout, NULL, 0);
 340
 341         /* Done */
 342         return (0);
 343 }
 344
 345 /*
 346  * Method for attaching a new hook
 347  */
 348 static  int
 349 ng_bridge_newhook(node_p node, hook_p hook, const char *name)
 350 {
 351         const priv_p priv = NG_NODE_PRIVATE(node);
 352
 353         /* Check for a link hook */
 354         if (strncmp(name, NG_BRIDGE_HOOK_LINK_PREFIX,
 355             strlen(NG_BRIDGE_HOOK_LINK_PREFIX)) == 0) {
 356                 const char *cp;
 357                 char *eptr;
 358                 u_long linkNum;
 359
 360                 cp = name + strlen(NG_BRIDGE_HOOK_LINK_PREFIX);
 361                 if (!isdigit(*cp) || (cp[0] == '0' && cp[1] != '\0'))
 362                         return (EINVAL);
 363                 linkNum = strtoul(cp, &eptr, 10);
 364                 if (*eptr != '\0' || linkNum >= NG_BRIDGE_MAX_LINKS)
 365                         return (EINVAL);
 366                 if (priv->links[linkNum] != NULL)
 367                         return (EISCONN);
 368                 priv->links[linkNum] = malloc(sizeof(*priv->links[linkNum]),
 369                     M_NETGRAPH_BRIDGE, M_NOWAIT|M_ZERO);
 370                 if (priv->links[linkNum] == NULL)
 371                         return (ENOMEM);
 372                 priv->links[linkNum]->hook = hook;
 373                 NG_HOOK_SET_PRIVATE(hook, (void *)linkNum);
 374                 priv->numLinks++;
 375                 return (0);
 376         }
 377
 378         /* Unknown hook name */
 379         return (EINVAL);
 380 }
 381
 382 /*
 383  * Receive a control message
 384  */
 385 static int
 386 ng_bridge_rcvmsg(node_p node, item_p item, hook_p lasthook)
 387 {
 388         const priv_p priv = NG_NODE_PRIVATE(node);
 389         struct ng_mesg *resp = NULL;
 390         int error = 0;
 391         struct ng_mesg *msg;
 392
 393         NGI_GET_MSG(item, msg);
 394         switch (msg->header.typecookie) {
 395         case NGM_BRIDGE_COOKIE:
 396                 switch (msg->header.cmd) {
 397                 case NGM_BRIDGE_GET_CONFIG:
 398                     {
 399                         struct ng_bridge_config *conf;
 400
 401                         NG_MKRESPONSE(resp, msg,
 402                             sizeof(struct ng_bridge_config), M_NOWAIT);
 403                         if (resp == NULL) {
 404                                 error = ENOMEM;
 405                                 break;
 406                         }
 407                         conf = (struct ng_bridge_config *)resp->data;
 408                         *conf = priv->conf;     /* no sanity checking needed */
 409                         break;
 410                     }
 411                 case NGM_BRIDGE_SET_CONFIG:
 412                     {
 413                         struct ng_bridge_config *conf;
 414                         int i;
 415
 416                         if (msg->header.arglen
 417                             != sizeof(struct ng_bridge_config)) {
 418                                 error = EINVAL;
 419                                 break;
 420                         }
 421                         conf = (struct ng_bridge_config *)msg->data;
 422                         priv->conf = *conf;
 423                         for (i = 0; i < NG_BRIDGE_MAX_LINKS; i++)
 424                                 priv->conf.ipfw[i] = !!priv->conf.ipfw[i];
 425                         break;
 426                     }
 427                 case NGM_BRIDGE_RESET:
 428                     {
 429                         int i;
 430
 431                         /* Flush all entries in the hash table */
 432                         ng_bridge_remove_hosts(priv, -1);
 433
 434                         /* Reset all loop detection counters and stats */
 435                         for (i = 0; i < NG_BRIDGE_MAX_LINKS; i++) {
 436                                 if (priv->links[i] == NULL)
 437                                         continue;
 438                                 priv->links[i]->loopCount = 0;
 439                                 bzero(&priv->links[i]->stats,
 440                                     sizeof(priv->links[i]->stats));
 441                         }
 442                         break;
 443                     }
 444                 case NGM_BRIDGE_GET_STATS:
 445                 case NGM_BRIDGE_CLR_STATS:
 446                 case NGM_BRIDGE_GETCLR_STATS:
 447                     {
 448                         struct ng_bridge_link *link;
 449                         int linkNum;
 450
 451                         /* Get link number */
 452                         if (msg->header.arglen != sizeof(u_int32_t)) {
 453                                 error = EINVAL;
 454                                 break;
 455                         }
 456                         linkNum = *((u_int32_t *)msg->data);
 457                         if (linkNum < 0 || linkNum >= NG_BRIDGE_MAX_LINKS) {
 458                                 error = EINVAL;
 459                                 break;
 460                         }
 461                         if ((link = priv->links[linkNum]) == NULL) {
 462                                 error = ENOTCONN;
 463                                 break;
 464                         }
 465
 466                         /* Get/clear stats */
 467                         if (msg->header.cmd != NGM_BRIDGE_CLR_STATS) {
 468                                 NG_MKRESPONSE(resp, msg,
 469                                     sizeof(link->stats), M_NOWAIT);
 470                                 if (resp == NULL) {
 471                                         error = ENOMEM;
 472                                         break;
 473                                 }
 474                                 bcopy(&link->stats,
 475                                     resp->data, sizeof(link->stats));
 476                         }
 477                         if (msg->header.cmd != NGM_BRIDGE_GET_STATS)
 478                                 bzero(&link->stats, sizeof(link->stats));
 479                         break;
 480                     }
 481                 case NGM_BRIDGE_GET_TABLE:
 482                     {
 483                         struct ng_bridge_host_ary *ary;
 484                         struct ng_bridge_hent *hent;
 485                         int i = 0, bucket;
 486
 487                         NG_MKRESPONSE(resp, msg, sizeof(*ary)
 488                             + (priv->numHosts * sizeof(*ary->hosts)), M_NOWAIT);
 489                         if (resp == NULL) {
 490                                 error = ENOMEM;
 491                                 break;
 492                         }
 493                         ary = (struct ng_bridge_host_ary *)resp->data;
 494                         ary->numHosts = priv->numHosts;
 495                         for (bucket = 0; bucket < priv->numBuckets; bucket++) {
 496                                 SLIST_FOREACH(hent, &priv->tab[bucket], next)
 497                                         ary->hosts[i++] = hent->host;
 498                         }
 499                         break;
 500                     }
 501                 case NGM_BRIDGE_SET_PERSISTENT:
 502                     {
 503                         priv->persistent = 1;
 504                         break;
 505                     }
 506                 default:
 507                         error = EINVAL;
 508                         break;
 509                 }
 510                 break;
 511         default:
 512                 error = EINVAL;
 513                 break;
 514         }
 515
 516         /* Done */
 517         NG_RESPOND_MSG(error, node, item, resp);
 518         NG_FREE_MSG(msg);
 519         return (error);
 520 }
 521
 522 /*
 523  * Receive data on a hook
 524  */
 525 static int
 526 ng_bridge_rcvdata(hook_p hook, item_p item)
 527 {
 528         const node_p node = NG_HOOK_NODE(hook);
 529         const priv_p priv = NG_NODE_PRIVATE(node);
 530         struct ng_bridge_host *host;
 531         struct ng_bridge_link *link;
 532         struct ether_header *eh;
 533         int error = 0, linkNum, linksSeen;
 534         int manycast;
 535         struct mbuf *m;
 536         struct ng_bridge_link *firstLink;
 537
 538         NGI_GET_M(item, m);
 539         /* Get link number */
 540         linkNum = (intptr_t)NG_HOOK_PRIVATE(hook);
 541         KASSERT(linkNum >= 0 && linkNum < NG_BRIDGE_MAX_LINKS,
 542             ("%s: linkNum=%u", __func__, linkNum));
 543         link = priv->links[linkNum];
 544         KASSERT(link != NULL, ("%s: link%d null", __func__, linkNum));
 545
 546         /* Sanity check packet and pull up header */
 547         if (m->m_pkthdr.len < ETHER_HDR_LEN) {
 548                 link->stats.recvRunts++;
 549                 NG_FREE_ITEM(item);
 550                 NG_FREE_M(m);
 551                 return (EINVAL);
 552         }
 553         if (m->m_len < ETHER_HDR_LEN && !(m = m_pullup(m, ETHER_HDR_LEN))) {
 554                 link->stats.memoryFailures++;
 555                 NG_FREE_ITEM(item);
 556                 return (ENOBUFS);
 557         }
 558         eh = mtod(m, struct ether_header *);
 559         if ((eh->ether_shost[0] & 1) != 0) {
 560                 link->stats.recvInvalid++;
 561                 NG_FREE_ITEM(item);
 562                 NG_FREE_M(m);
 563                 return (EINVAL);
 564         }
 565
 566         /* Is link disabled due to a loopback condition? */
 567         if (link->loopCount != 0) {
 568                 link->stats.loopDrops++;
 569                 NG_FREE_ITEM(item);
 570                 NG_FREE_M(m);
 571                 return (ELOOP);         /* XXX is this an appropriate error? */
 572         }
 573
 574         /* Update stats */
 575         link->stats.recvPackets++;
 576         link->stats.recvOctets += m->m_pkthdr.len;
 577         if ((manycast = (eh->ether_dhost[0] & 1)) != 0) {
 578                 if (ETHER_EQUAL(eh->ether_dhost, ng_bridge_bcast_addr)) {
 579                         link->stats.recvBroadcasts++;
 580                         manycast = 2;
 581                 } else
 582                         link->stats.recvMulticasts++;
 583         }
 584
 585         /* Look up packet's source Ethernet address in hashtable */
 586         if ((host = ng_bridge_get(priv, eh->ether_shost)) != NULL) {
 587
 588                 /* Update time since last heard from this host */
 589                 host->staleness = 0;
 590
 591                 /* Did host jump to a different link? */
 592                 if (host->linkNum != linkNum) {
 593
 594                         /*
 595                          * If the host's old link was recently established
 596                          * on the old link and it's already jumped to a new
 597                          * link, declare a loopback condition.
 598                          */
 599                         if (host->age < priv->conf.minStableAge) {
 600
 601                                 /* Log the problem */
 602                                 if (priv->conf.debugLevel >= 2) {
 603                                         struct ifnet *ifp = m->m_pkthdr.rcvif;
 604                                         char suffix[32];
 605
 606                                         if (ifp != NULL)
 607                                                 snprintf(suffix, sizeof(suffix),
 608                                                     " (%s)", ifp->if_xname);
 609                                         else
 610                                                 *suffix = '\0';
 611                                         log(LOG_WARNING, "ng_bridge: %s:"
 612                                             " loopback detected on %s%s\n",
 613                                             ng_bridge_nodename(node),
 614                                             NG_HOOK_NAME(hook), suffix);
 615                                 }
 616
 617                                 /* Mark link as linka non grata */
 618                                 link->loopCount = priv->conf.loopTimeout;
 619                                 link->stats.loopDetects++;
 620
 621                                 /* Forget all hosts on this link */
 622                                 ng_bridge_remove_hosts(priv, linkNum);
 623
 624                                 /* Drop packet */
 625                                 link->stats.loopDrops++;
 626                                 NG_FREE_ITEM(item);
 627                                 NG_FREE_M(m);
 628                                 return (ELOOP);         /* XXX appropriate? */
 629                         }
 630
 631                         /* Move host over to new link */
 632                         host->linkNum = linkNum;
 633                         host->age = 0;
 634                 }
 635         } else {
 636                 if (!ng_bridge_put(priv, eh->ether_shost, linkNum)) {
 637                         link->stats.memoryFailures++;
 638                         NG_FREE_ITEM(item);
 639                         NG_FREE_M(m);
 640                         return (ENOMEM);
 641                 }
 642         }
 643
 644         /* Run packet through ipfw processing, if enabled */
 645 #if 0
 646         if (priv->conf.ipfw[linkNum] && V_fw_enable && V_ip_fw_chk_ptr != NULL) {
 647                 /* XXX not implemented yet */
 648         }
 649 #endif
 650
 651         /*
 652          * If unicast and destination host known, deliver to host's link,
 653          * unless it is the same link as the packet came in on.
 654          */
 655         if (!manycast) {
 656
 657                 /* Determine packet destination link */
 658                 if ((host = ng_bridge_get(priv, eh->ether_dhost)) != NULL) {
 659                         struct ng_bridge_link *const destLink
 660                             = priv->links[host->linkNum];
 661
 662                         /* If destination same as incoming link, do nothing */
 663                         KASSERT(destLink != NULL,
 664                             ("%s: link%d null", __func__, host->linkNum));
 665                         if (destLink == link) {
 666                                 NG_FREE_ITEM(item);
 667                                 NG_FREE_M(m);
 668                                 return (0);
 669                         }
 670
 671                         /* Deliver packet out the destination link */
 672                         destLink->stats.xmitPackets++;
 673                         destLink->stats.xmitOctets += m->m_pkthdr.len;
 674                         NG_FWD_NEW_DATA(error, item, destLink->hook, m);
 675                         return (error);
 676                 }
 677
 678                 /* Destination host is not known */
 679                 link->stats.recvUnknown++;
 680         }
 681
 682         /* Distribute unknown, multicast, broadcast pkts to all other links */
 683         firstLink = NULL;
 684         for (linkNum = linksSeen = 0; linksSeen <= priv->numLinks; linkNum++) {
 685                 struct ng_bridge_link *destLink;
 686                 struct mbuf *m2 = NULL;
 687
 688                 /*
 689                  * If we have checked all the links then now
 690                  * send the original on its reserved link
 691                  */
 692                 if (linksSeen == priv->numLinks) {
 693                         /* If we never saw a good link, leave. */
 694                         if (firstLink == NULL) {
 695                                 NG_FREE_ITEM(item);
 696                                 NG_FREE_M(m);
 697                                 return (0);
 698                         }
 699                         destLink = firstLink;
 700                 } else {
 701                         destLink = priv->links[linkNum];
 702                         if (destLink != NULL)
 703                                 linksSeen++;
 704                         /* Skip incoming link and disconnected links */
 705                         if (destLink == NULL || destLink == link) {
 706                                 continue;
 707                         }
 708                         if (firstLink == NULL) {
 709                                 /*
 710                                  * This is the first usable link we have found.
 711                                  * Reserve it for the originals.
 712                                  * If we never find another we save a copy.
 713                                  */
 714                                 firstLink = destLink;
 715                                 continue;
 716                         }
 717
 718                         /*
 719                          * It's usable link but not the reserved (first) one.
 720                          * Copy mbuf info for sending.
 721                          */
 722                         m2 = m_dup(m, M_DONTWAIT);      /* XXX m_copypacket() */
 723                         if (m2 == NULL) {
 724                                 link->stats.memoryFailures++;
 725                                 NG_FREE_ITEM(item);
 726                                 NG_FREE_M(m);
 727                                 return (ENOBUFS);
 728                         }
 729                 }
 730
 731                 /* Update stats */
 732                 destLink->stats.xmitPackets++;
 733                 destLink->stats.xmitOctets += m->m_pkthdr.len;
 734                 switch (manycast) {
 735                 case 0:                                 /* unicast */
 736                         break;
 737                 case 1:                                 /* multicast */
 738                         destLink->stats.xmitMulticasts++;
 739                         break;
 740                 case 2:                                 /* broadcast */
 741                         destLink->stats.xmitBroadcasts++;
 742                         break;
 743                 }
 744
 745                 /* Send packet */
 746                 if (destLink == firstLink) {
 747                         /*
 748                          * If we've sent all the others, send the original
 749                          * on the first link we found.
 750                          */
 751                         NG_FWD_NEW_DATA(error, item, destLink->hook, m);
 752                         break; /* always done last - not really needed. */
 753                 } else {
 754                         NG_SEND_DATA_ONLY(error, destLink->hook, m2);
 755                 }
 756         }
 757         return (error);
 758 }
 759
 760 /*
 761  * Shutdown node
 762  */
 763 static int
 764 ng_bridge_shutdown(node_p node)
 765 {
 766         const priv_p priv = NG_NODE_PRIVATE(node);
 767
 768         /*
 769          * Shut down everything including the timer.  Even if the
 770          * callout has already been dequeued and is about to be
 771          * run, ng_bridge_timeout() won't be fired as the node
 772          * is already marked NGF_INVALID, so we're safe to free
 773          * the node now.
 774          */
 775         KASSERT(priv->numLinks == 0 && priv->numHosts == 0,
 776             ("%s: numLinks=%d numHosts=%d",
 777             __func__, priv->numLinks, priv->numHosts));
 778         ng_uncallout(&priv->timer, node);
 779         NG_NODE_SET_PRIVATE(node, NULL);
 780         NG_NODE_UNREF(node);
 781         free(priv->tab, M_NETGRAPH_BRIDGE);
 782         free(priv, M_NETGRAPH_BRIDGE);
 783         return (0);
 784 }
 785
 786 /*
 787  * Hook disconnection.
 788  */
 789 static int
 790 ng_bridge_disconnect(hook_p hook)
 791 {
 792         const priv_p priv = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
 793         int linkNum;
 794
 795         /* Get link number */
 796         linkNum = (intptr_t)NG_HOOK_PRIVATE(hook);
 797         KASSERT(linkNum >= 0 && linkNum < NG_BRIDGE_MAX_LINKS,
 798             ("%s: linkNum=%u", __func__, linkNum));
 799
 800         /* Remove all hosts associated with this link */
 801         ng_bridge_remove_hosts(priv, linkNum);
 802
 803         /* Free associated link information */
 804         KASSERT(priv->links[linkNum] != NULL, ("%s: no link", __func__));
 805         free(priv->links[linkNum], M_NETGRAPH_BRIDGE);
 806         priv->links[linkNum] = NULL;
 807         priv->numLinks--;
 808
 809         /* If no more hooks, go away */
 810         if ((NG_NODE_NUMHOOKS(NG_HOOK_NODE(hook)) == 0)
 811             && (NG_NODE_IS_VALID(NG_HOOK_NODE(hook)))
 812             && !priv->persistent) {
 813                 ng_rmnode_self(NG_HOOK_NODE(hook));
 814         }
 815         return (0);
 816 }
 817
 818 /******************************************************************
 819                     HASH TABLE FUNCTIONS
 820 ******************************************************************/
 821
 822 /*
 823  * Hash algorithm
 824  */
 825 #define HASH(addr,mask)         ( (((const u_int16_t *)(addr))[0]       \
 826                                  ^ ((const u_int16_t *)(addr))[1]       \
 827                                  ^ ((const u_int16_t *)(addr))[2]) & (mask) )
 828
 829 /*
 830  * Find a host entry in the table.
 831  */
 832 static struct ng_bridge_host *
 833 ng_bridge_get(priv_p priv, const u_char *addr)
 834 {
 835         const int bucket = HASH(addr, priv->hashMask);
 836         struct ng_bridge_hent *hent;
 837
 838         SLIST_FOREACH(hent, &priv->tab[bucket], next) {
 839                 if (ETHER_EQUAL(hent->host.addr, addr))
 840                         return (&hent->host);
 841         }
 842         return (NULL);
 843 }
 844
 845 /*
 846  * Add a new host entry to the table. This assumes the host doesn't
 847  * already exist in the table. Returns 1 on success, 0 if there
 848  * was a memory allocation failure.
 849  */
 850 static int
 851 ng_bridge_put(priv_p priv, const u_char *addr, int linkNum)
 852 {
 853         const int bucket = HASH(addr, priv->hashMask);
 854         struct ng_bridge_hent *hent;
 855
 856 #ifdef INVARIANTS
 857         /* Assert that entry does not already exist in hashtable */
 858         SLIST_FOREACH(hent, &priv->tab[bucket], next) {
 859                 KASSERT(!ETHER_EQUAL(hent->host.addr, addr),
 860                     ("%s: entry %6D exists in table", __func__, addr, ":"));
 861         }
 862 #endif
 863
 864         /* Allocate and initialize new hashtable entry */
 865         hent = malloc(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         newTab = malloc(newNumBuckets * sizeof(*newTab),
 910             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 static void
 977 ng_bridge_timeout(node_p node, hook_p hook, void *arg1, int arg2)
 978 {
 979         const priv_p priv = NG_NODE_PRIVATE(node);
 980         int bucket;
 981         int counter = 0;
 982         int linkNum;
 983
 984         /* Update host time counters and remove stale entries */
 985         for (bucket = 0; bucket < priv->numBuckets; bucket++) {
 986                 struct ng_bridge_hent **hptr = &SLIST_FIRST(&priv->tab[bucket]);
 987
 988                 while (*hptr != NULL) {
 989                         struct ng_bridge_hent *const hent = *hptr;
 990
 991                         /* Make sure host's link really exists */
 992                         KASSERT(priv->links[hent->host.linkNum] != NULL,
 993                             ("%s: host %6D on nonexistent link %d\n",
 994                             __func__, hent->host.addr, ":",
 995                             hent->host.linkNum));
 996
 997                         /* Remove hosts we haven't heard from in a while */
 998                         if (++hent->host.staleness >= priv->conf.maxStaleness) {
 999                                 *hptr = SLIST_NEXT(hent, next);
1000                                 free(hent, M_NETGRAPH_BRIDGE);
1001                                 priv->numHosts--;
1002                         } else {
1003                                 if (hent->host.age < 0xffff)
1004                                         hent->host.age++;
1005                                 hptr = &SLIST_NEXT(hent, next);
1006                                 counter++;
1007                         }
1008                 }
1009         }
1010         KASSERT(priv->numHosts == counter,
1011             ("%s: hosts: %d != %d", __func__, priv->numHosts, counter));
1012
1013         /* Decrease table size if necessary */
1014         ng_bridge_rehash(priv);
1015
1016         /* Decrease loop counter on muted looped back links */
1017         for (counter = linkNum = 0; linkNum < NG_BRIDGE_MAX_LINKS; linkNum++) {
1018                 struct ng_bridge_link *const link = priv->links[linkNum];
1019
1020                 if (link != NULL) {
1021                         if (link->loopCount != 0) {
1022                                 link->loopCount--;
1023                                 if (link->loopCount == 0
1024                                     && priv->conf.debugLevel >= 2) {
1025                                         log(LOG_INFO, "ng_bridge: %s:"
1026                                             " restoring looped back link%d\n",
1027                                             ng_bridge_nodename(node), linkNum);
1028                                 }
1029                         }
1030                         counter++;
1031                 }
1032         }
1033         KASSERT(priv->numLinks == counter,
1034             ("%s: links: %d != %d", __func__, priv->numLinks, counter));
1035
1036         /* Register a new timeout, keeping the existing node reference */
1037         ng_callout(&priv->timer, node, NULL, hz, ng_bridge_timeout, NULL, 0);
1038 }
1039
1040 /*
1041  * Return node's "name", even if it doesn't have one.
1042  */
1043 static const char *
1044 ng_bridge_nodename(node_p node)
1045 {
1046         static char name[NG_NODESIZ];
1047
1048         if (NG_NODE_NAME(node) != NULL)
1049                 snprintf(name, sizeof(name), "%s", NG_NODE_NAME(node));
1050         else
1051                 snprintf(name, sizeof(name), "[%x]", ng_node2ID(node));
1052         return name;
1053 }
1054