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
  81 #ifdef NG_SEPARATE_MALLOC
  82 MALLOC_DEFINE(M_NETGRAPH_BRIDGE, "netgraph_bridge", "netgraph bridge node ");
  83 #else
  84 #define M_NETGRAPH_BRIDGE M_NETGRAPH
  85 #endif
  86
  87 /* Per-link private data */
  88 struct ng_bridge_link {
  89         hook_p                          hook;           /* netgraph hook */
  90         u_int16_t                       loopCount;      /* loop ignore timer */
  91         struct ng_bridge_link_stats     stats;          /* link stats */
  92 };
  93
  94 /* Per-node private data */
  95 struct ng_bridge_private {
  96         struct ng_bridge_bucket *tab;           /* hash table bucket array */
  97         struct ng_bridge_link   *links[NG_BRIDGE_MAX_LINKS];
  98         struct ng_bridge_config conf;           /* node configuration */
  99         node_p                  node;           /* netgraph node */
 100         u_int                   numHosts;       /* num entries in table */
 101         u_int                   numBuckets;     /* num buckets in table */
 102         u_int                   hashMask;       /* numBuckets - 1 */
 103         int                     numLinks;       /* num connected links */
 104         struct callout          timer;          /* one second periodic timer */
 105 };
 106 typedef struct ng_bridge_private *priv_p;
 107
 108 /* Information about a host, stored in a hash table entry */
 109 struct ng_bridge_hent {
 110         struct ng_bridge_host           host;   /* actual host info */
 111         SLIST_ENTRY(ng_bridge_hent)     next;   /* next entry in bucket */
 112 };
 113
 114 /* Hash table bucket declaration */
 115 SLIST_HEAD(ng_bridge_bucket, ng_bridge_hent);
 116
 117 /* Netgraph node methods */
 118 static ng_constructor_t ng_bridge_constructor;
 119 static ng_rcvmsg_t      ng_bridge_rcvmsg;
 120 static ng_shutdown_t    ng_bridge_shutdown;
 121 static ng_newhook_t     ng_bridge_newhook;
 122 static ng_rcvdata_t     ng_bridge_rcvdata;
 123 static ng_disconnect_t  ng_bridge_disconnect;
 124
 125 /* Other internal functions */
 126 static struct   ng_bridge_host *ng_bridge_get(priv_p priv, const u_char *addr);
 127 static int      ng_bridge_put(priv_p priv, const u_char *addr, int linkNum);
 128 static void     ng_bridge_rehash(priv_p priv);
 129 static void     ng_bridge_remove_hosts(priv_p priv, int linkNum);
 130 static void     ng_bridge_timeout(void *arg);
 131 static const    char *ng_bridge_nodename(node_p node);
 132
 133 /* Ethernet broadcast */
 134 static const u_char ng_bridge_bcast_addr[ETHER_ADDR_LEN] =
 135     { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
 136
 137 /* Store each hook's link number in the private field */
 138 #define LINK_NUM(hook)          (*(u_int16_t *)(&(hook)->private))
 139
 140 /* Compare Ethernet addresses using 32 and 16 bit words instead of bytewise */
 141 #define ETHER_EQUAL(a,b)        (((const u_int32_t *)(a))[0] \
 142                                         == ((const u_int32_t *)(b))[0] \
 143                                     && ((const u_int16_t *)(a))[2] \
 144                                         == ((const u_int16_t *)(b))[2])
 145
 146 /* Minimum and maximum number of hash buckets. Must be a power of two. */
 147 #define MIN_BUCKETS             (1 << 5)        /* 32 */
 148 #define MAX_BUCKETS             (1 << 14)       /* 16384 */
 149
 150 /* Configuration default values */
 151 #define DEFAULT_LOOP_TIMEOUT    60
 152 #define DEFAULT_MAX_STALENESS   (15 * 60)       /* same as ARP timeout */
 153 #define DEFAULT_MIN_STABLE_AGE  1
 154
 155 /******************************************************************
 156                     NETGRAPH PARSE TYPES
 157 ******************************************************************/
 158
 159 /*
 160  * How to determine the length of the table returned by NGM_BRIDGE_GET_TABLE
 161  */
 162 static int
 163 ng_bridge_getTableLength(const struct ng_parse_type *type,
 164         const u_char *start, const u_char *buf)
 165 {
 166         const struct ng_bridge_host_ary *const hary
 167             = (const struct ng_bridge_host_ary *)(buf - sizeof(u_int32_t));
 168
 169         return hary->numHosts;
 170 }
 171
 172 /* Parse type for struct ng_bridge_host_ary */
 173 static const struct ng_parse_struct_field ng_bridge_host_type_fields[]
 174         = NG_BRIDGE_HOST_TYPE_INFO(&ng_parse_enaddr_type);
 175 static const struct ng_parse_type ng_bridge_host_type = {
 176         &ng_parse_struct_type,
 177         &ng_bridge_host_type_fields
 178 };
 179 static const struct ng_parse_array_info ng_bridge_hary_type_info = {
 180         &ng_bridge_host_type,
 181         ng_bridge_getTableLength
 182 };
 183 static const struct ng_parse_type ng_bridge_hary_type = {
 184         &ng_parse_array_type,
 185         &ng_bridge_hary_type_info
 186 };
 187 static const struct ng_parse_struct_field ng_bridge_host_ary_type_fields[]
 188         = NG_BRIDGE_HOST_ARY_TYPE_INFO(&ng_bridge_hary_type);
 189 static const struct ng_parse_type ng_bridge_host_ary_type = {
 190         &ng_parse_struct_type,
 191         &ng_bridge_host_ary_type_fields
 192 };
 193
 194 /* Parse type for struct ng_bridge_config */
 195 static const struct ng_parse_fixedarray_info ng_bridge_ipfwary_type_info = {
 196         &ng_parse_uint8_type,
 197         NG_BRIDGE_MAX_LINKS
 198 };
 199 static const struct ng_parse_type ng_bridge_ipfwary_type = {
 200         &ng_parse_fixedarray_type,
 201         &ng_bridge_ipfwary_type_info
 202 };
 203 static const struct ng_parse_struct_field ng_bridge_config_type_fields[]
 204         = NG_BRIDGE_CONFIG_TYPE_INFO(&ng_bridge_ipfwary_type);
 205 static const struct ng_parse_type ng_bridge_config_type = {
 206         &ng_parse_struct_type,
 207         &ng_bridge_config_type_fields
 208 };
 209
 210 /* Parse type for struct ng_bridge_link_stat */
 211 static const struct ng_parse_struct_field ng_bridge_stats_type_fields[]
 212         = NG_BRIDGE_STATS_TYPE_INFO;
 213 static const struct ng_parse_type ng_bridge_stats_type = {
 214         &ng_parse_struct_type,
 215         &ng_bridge_stats_type_fields
 216 };
 217
 218 /* List of commands and how to convert arguments to/from ASCII */
 219 static const struct ng_cmdlist ng_bridge_cmdlist[] = {
 220         {
 221           NGM_BRIDGE_COOKIE,
 222           NGM_BRIDGE_SET_CONFIG,
 223           "setconfig",
 224           &ng_bridge_config_type,
 225           NULL
 226         },
 227         {
 228           NGM_BRIDGE_COOKIE,
 229           NGM_BRIDGE_GET_CONFIG,
 230           "getconfig",
 231           NULL,
 232           &ng_bridge_config_type
 233         },
 234         {
 235           NGM_BRIDGE_COOKIE,
 236           NGM_BRIDGE_RESET,
 237           "reset",
 238           NULL,
 239           NULL
 240         },
 241         {
 242           NGM_BRIDGE_COOKIE,
 243           NGM_BRIDGE_GET_STATS,
 244           "getstats",
 245           &ng_parse_uint32_type,
 246           &ng_bridge_stats_type
 247         },
 248         {
 249           NGM_BRIDGE_COOKIE,
 250           NGM_BRIDGE_CLR_STATS,
 251           "clrstats",
 252           &ng_parse_uint32_type,
 253           NULL
 254         },
 255         {
 256           NGM_BRIDGE_COOKIE,
 257           NGM_BRIDGE_GETCLR_STATS,
 258           "getclrstats",
 259           &ng_parse_uint32_type,
 260           &ng_bridge_stats_type
 261         },
 262         {
 263           NGM_BRIDGE_COOKIE,
 264           NGM_BRIDGE_GET_TABLE,
 265           "gettable",
 266           NULL,
 267           &ng_bridge_host_ary_type
 268         },
 269         { 0 }
 270 };
 271
 272 /* Node type descriptor */
 273 static struct ng_type ng_bridge_typestruct = {
 274         .version =      NG_ABI_VERSION,
 275         .name =         NG_BRIDGE_NODE_TYPE,
 276         .constructor =  ng_bridge_constructor,
 277         .rcvmsg =       ng_bridge_rcvmsg,
 278         .shutdown =     ng_bridge_shutdown,
 279         .newhook =      ng_bridge_newhook,
 280         .rcvdata =      ng_bridge_rcvdata,
 281         .disconnect =   ng_bridge_disconnect,
 282         .cmdlist =      ng_bridge_cmdlist,
 283 };
 284 NETGRAPH_INIT(bridge, &ng_bridge_typestruct);
 285
 286 /******************************************************************
 287                     NETGRAPH NODE METHODS
 288 ******************************************************************/
 289
 290 /*
 291  * Node constructor
 292  */
 293 static int
 294 ng_bridge_constructor(node_p node)
 295 {
 296         priv_p priv;
 297
 298         /* Allocate and initialize private info */
 299         MALLOC(priv, priv_p, sizeof(*priv), M_NETGRAPH_BRIDGE, M_NOWAIT | M_ZERO);
 300         if (priv == NULL)
 301                 return (ENOMEM);
 302         callout_init(&priv->timer, 0);
 303
 304         /* Allocate and initialize hash table, etc. */
 305         MALLOC(priv->tab, struct ng_bridge_bucket *,
 306             MIN_BUCKETS * sizeof(*priv->tab), M_NETGRAPH_BRIDGE, M_NOWAIT | M_ZERO);
 307         if (priv->tab == NULL) {
 308                 FREE(priv, M_NETGRAPH_BRIDGE);
 309                 return (ENOMEM);
 310         }
 311         priv->numBuckets = MIN_BUCKETS;
 312         priv->hashMask = MIN_BUCKETS - 1;
 313         priv->conf.debugLevel = 1;
 314         priv->conf.loopTimeout = DEFAULT_LOOP_TIMEOUT;
 315         priv->conf.maxStaleness = DEFAULT_MAX_STALENESS;
 316         priv->conf.minStableAge = DEFAULT_MIN_STABLE_AGE;
 317
 318         /*
 319          * This node has all kinds of stuff that could be screwed by SMP.
 320          * Until it gets it's own internal protection, we go through in
 321          * single file. This could hurt a machine bridging beteen two
 322          * GB ethernets so it should be fixed.
 323          * When it's fixed the process SHOULD NOT SLEEP, spinlocks please!
 324          * (and atomic ops )
 325          */
 326         NG_NODE_FORCE_WRITER(node);
 327         NG_NODE_SET_PRIVATE(node, priv);
 328         priv->node = node;
 329
 330         /* Start timer; timer is always running while node is alive */
 331         callout_reset(&priv->timer, hz, ng_bridge_timeout, priv->node);
 332
 333         /* Done */
 334         return (0);
 335 }
 336
 337 /*
 338  * Method for attaching a new hook
 339  */
 340 static  int
 341 ng_bridge_newhook(node_p node, hook_p hook, const char *name)
 342 {
 343         const priv_p priv = NG_NODE_PRIVATE(node);
 344
 345         /* Check for a link hook */
 346         if (strncmp(name, NG_BRIDGE_HOOK_LINK_PREFIX,
 347             strlen(NG_BRIDGE_HOOK_LINK_PREFIX)) == 0) {
 348                 const char *cp;
 349                 char *eptr;
 350                 u_long linkNum;
 351
 352                 cp = name + strlen(NG_BRIDGE_HOOK_LINK_PREFIX);
 353                 if (!isdigit(*cp) || (cp[0] == '0' && cp[1] != '\0'))
 354                         return (EINVAL);
 355                 linkNum = strtoul(cp, &eptr, 10);
 356                 if (*eptr != '\0' || linkNum >= NG_BRIDGE_MAX_LINKS)
 357                         return (EINVAL);
 358                 if (priv->links[linkNum] != NULL)
 359                         return (EISCONN);
 360                 MALLOC(priv->links[linkNum], struct ng_bridge_link *,
 361                     sizeof(*priv->links[linkNum]), M_NETGRAPH_BRIDGE, M_NOWAIT|M_ZERO);
 362                 if (priv->links[linkNum] == NULL)
 363                         return (ENOMEM);
 364                 priv->links[linkNum]->hook = hook;
 365                 NG_HOOK_SET_PRIVATE(hook, (void *)linkNum);
 366                 priv->numLinks++;
 367                 return (0);
 368         }
 369
 370         /* Unknown hook name */
 371         return (EINVAL);
 372 }
 373
 374 /*
 375  * Receive a control message
 376  */
 377 static int
 378 ng_bridge_rcvmsg(node_p node, item_p item, hook_p lasthook)
 379 {
 380         const priv_p priv = NG_NODE_PRIVATE(node);
 381         struct ng_mesg *resp = NULL;
 382         int error = 0;
 383         struct ng_mesg *msg;
 384
 385         NGI_GET_MSG(item, msg);
 386         switch (msg->header.typecookie) {
 387         case NGM_BRIDGE_COOKIE:
 388                 switch (msg->header.cmd) {
 389                 case NGM_BRIDGE_GET_CONFIG:
 390                     {
 391                         struct ng_bridge_config *conf;
 392
 393                         NG_MKRESPONSE(resp, msg,
 394                             sizeof(struct ng_bridge_config), M_NOWAIT);
 395                         if (resp == NULL) {
 396                                 error = ENOMEM;
 397                                 break;
 398                         }
 399                         conf = (struct ng_bridge_config *)resp->data;
 400                         *conf = priv->conf;     /* no sanity checking needed */
 401                         break;
 402                     }
 403                 case NGM_BRIDGE_SET_CONFIG:
 404                     {
 405                         struct ng_bridge_config *conf;
 406                         int i;
 407
 408                         if (msg->header.arglen
 409                             != sizeof(struct ng_bridge_config)) {
 410                                 error = EINVAL;
 411                                 break;
 412                         }
 413                         conf = (struct ng_bridge_config *)msg->data;
 414                         priv->conf = *conf;
 415                         for (i = 0; i < NG_BRIDGE_MAX_LINKS; i++)
 416                                 priv->conf.ipfw[i] = !!priv->conf.ipfw[i];
 417                         break;
 418                     }
 419                 case NGM_BRIDGE_RESET:
 420                     {
 421                         int i;
 422
 423                         /* Flush all entries in the hash table */
 424                         ng_bridge_remove_hosts(priv, -1);
 425
 426                         /* Reset all loop detection counters and stats */
 427                         for (i = 0; i < NG_BRIDGE_MAX_LINKS; i++) {
 428                                 if (priv->links[i] == NULL)
 429                                         continue;
 430                                 priv->links[i]->loopCount = 0;
 431                                 bzero(&priv->links[i]->stats,
 432                                     sizeof(priv->links[i]->stats));
 433                         }
 434                         break;
 435                     }
 436                 case NGM_BRIDGE_GET_STATS:
 437                 case NGM_BRIDGE_CLR_STATS:
 438                 case NGM_BRIDGE_GETCLR_STATS:
 439                     {
 440                         struct ng_bridge_link *link;
 441                         int linkNum;
 442
 443                         /* Get link number */
 444                         if (msg->header.arglen != sizeof(u_int32_t)) {
 445                                 error = EINVAL;
 446                                 break;
 447                         }
 448                         linkNum = *((u_int32_t *)msg->data);
 449                         if (linkNum < 0 || linkNum >= NG_BRIDGE_MAX_LINKS) {
 450                                 error = EINVAL;
 451                                 break;
 452                         }
 453                         if ((link = priv->links[linkNum]) == NULL) {
 454                                 error = ENOTCONN;
 455                                 break;
 456                         }
 457
 458                         /* Get/clear stats */
 459                         if (msg->header.cmd != NGM_BRIDGE_CLR_STATS) {
 460                                 NG_MKRESPONSE(resp, msg,
 461                                     sizeof(link->stats), M_NOWAIT);
 462                                 if (resp == NULL) {
 463                                         error = ENOMEM;
 464                                         break;
 465                                 }
 466                                 bcopy(&link->stats,
 467                                     resp->data, sizeof(link->stats));
 468                         }
 469                         if (msg->header.cmd != NGM_BRIDGE_GET_STATS)
 470                                 bzero(&link->stats, sizeof(link->stats));
 471                         break;
 472                     }
 473                 case NGM_BRIDGE_GET_TABLE:
 474                     {
 475                         struct ng_bridge_host_ary *ary;
 476                         struct ng_bridge_hent *hent;
 477                         int i = 0, bucket;
 478
 479                         NG_MKRESPONSE(resp, msg, sizeof(*ary)
 480                             + (priv->numHosts * sizeof(*ary->hosts)), M_NOWAIT);
 481                         if (resp == NULL) {
 482                                 error = ENOMEM;
 483                                 break;
 484                         }
 485                         ary = (struct ng_bridge_host_ary *)resp->data;
 486                         ary->numHosts = priv->numHosts;
 487                         for (bucket = 0; bucket < priv->numBuckets; bucket++) {
 488                                 SLIST_FOREACH(hent, &priv->tab[bucket], next)
 489                                         ary->hosts[i++] = hent->host;
 490                         }
 491                         break;
 492                     }
 493                 default:
 494                         error = EINVAL;
 495                         break;
 496                 }
 497                 break;
 498         default:
 499                 error = EINVAL;
 500                 break;
 501         }
 502
 503         /* Done */
 504         NG_RESPOND_MSG(error, node, item, resp);
 505         NG_FREE_MSG(msg);
 506         return (error);
 507 }
 508
 509 /*
 510  * Receive data on a hook
 511  */
 512 static int
 513 ng_bridge_rcvdata(hook_p hook, item_p item)
 514 {
 515         const node_p node = NG_HOOK_NODE(hook);
 516         const priv_p priv = NG_NODE_PRIVATE(node);
 517         struct ng_bridge_host *host;
 518         struct ng_bridge_link *link;
 519         struct ether_header *eh;
 520         int error = 0, linkNum, linksSeen;
 521         int manycast;
 522         struct mbuf *m;
 523         struct ng_bridge_link *firstLink;
 524
 525         NGI_GET_M(item, m);
 526         /* Get link number */
 527         linkNum = (intptr_t)NG_HOOK_PRIVATE(hook);
 528         KASSERT(linkNum >= 0 && linkNum < NG_BRIDGE_MAX_LINKS,
 529             ("%s: linkNum=%u", __func__, linkNum));
 530         link = priv->links[linkNum];
 531         KASSERT(link != NULL, ("%s: link%d null", __func__, linkNum));
 532
 533         /* Sanity check packet and pull up header */
 534         if (m->m_pkthdr.len < ETHER_HDR_LEN) {
 535                 link->stats.recvRunts++;
 536                 NG_FREE_ITEM(item);
 537                 NG_FREE_M(m);
 538                 return (EINVAL);
 539         }
 540         if (m->m_len < ETHER_HDR_LEN && !(m = m_pullup(m, ETHER_HDR_LEN))) {
 541                 link->stats.memoryFailures++;
 542                 NG_FREE_ITEM(item);
 543                 return (ENOBUFS);
 544         }
 545         eh = mtod(m, struct ether_header *);
 546         if ((eh->ether_shost[0] & 1) != 0) {
 547                 link->stats.recvInvalid++;
 548                 NG_FREE_ITEM(item);
 549                 NG_FREE_M(m);
 550                 return (EINVAL);
 551         }
 552
 553         /* Is link disabled due to a loopback condition? */
 554         if (link->loopCount != 0) {
 555                 link->stats.loopDrops++;
 556                 NG_FREE_ITEM(item);
 557                 NG_FREE_M(m);
 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                                                 snprintf(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                                             NG_HOOK_NAME(hook), 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_ITEM(item);
 614                                 NG_FREE_M(m);
 615                                 return (ELOOP);         /* XXX appropriate? */
 616                         }
 617
 618                         /* Move host over to new link */
 619                         host->linkNum = linkNum;
 620                         host->age = 0;
 621                 }
 622         } else {
 623                 if (!ng_bridge_put(priv, eh->ether_shost, linkNum)) {
 624                         link->stats.memoryFailures++;
 625                         NG_FREE_ITEM(item);
 626                         NG_FREE_M(m);
 627                         return (ENOMEM);
 628                 }
 629         }
 630
 631         /* Run packet through ipfw processing, if enabled */
 632         if (priv->conf.ipfw[linkNum] && fw_enable && ip_fw_chk_ptr != NULL) {
 633                 /* XXX not implemented yet */
 634         }
 635
 636         /*
 637          * If unicast and destination host known, deliver to host's link,
 638          * unless it is the same link as the packet came in on.
 639          */
 640         if (!manycast) {
 641
 642                 /* Determine packet destination link */
 643                 if ((host = ng_bridge_get(priv, eh->ether_dhost)) != NULL) {
 644                         struct ng_bridge_link *const destLink
 645                             = priv->links[host->linkNum];
 646
 647                         /* If destination same as incoming link, do nothing */
 648                         KASSERT(destLink != NULL,
 649                             ("%s: link%d null", __func__, host->linkNum));
 650                         if (destLink == link) {
 651                                 NG_FREE_ITEM(item);
 652                                 NG_FREE_M(m);
 653                                 return (0);
 654                         }
 655
 656                         /* Deliver packet out the destination link */
 657                         destLink->stats.xmitPackets++;
 658                         destLink->stats.xmitOctets += m->m_pkthdr.len;
 659                         NG_FWD_NEW_DATA(error, item, destLink->hook, m);
 660                         return (error);
 661                 }
 662
 663                 /* Destination host is not known */
 664                 link->stats.recvUnknown++;
 665         }
 666
 667         /* Distribute unknown, multicast, broadcast pkts to all other links */
 668         firstLink = NULL;
 669         for (linkNum = linksSeen = 0; linksSeen <= priv->numLinks; linkNum++) {
 670                 struct ng_bridge_link *destLink;
 671                 struct mbuf *m2 = NULL;
 672
 673                 /*
 674                  * If we have checked all the links then now
 675                  * send the original on its reserved link
 676                  */
 677                 if (linksSeen == priv->numLinks) {
 678                         /* If we never saw a good link, leave. */
 679                         if (firstLink == NULL) {
 680                                 NG_FREE_ITEM(item);
 681                                 NG_FREE_M(m);
 682                                 return (0);
 683                         }
 684                         destLink = firstLink;
 685                 } else {
 686                         destLink = priv->links[linkNum];
 687                         if (destLink != NULL)
 688                                 linksSeen++;
 689                         /* Skip incoming link and disconnected links */
 690                         if (destLink == NULL || destLink == link) {
 691                                 continue;
 692                         }
 693                         if (firstLink == NULL) {
 694                                 /*
 695                                  * This is the first usable link we have found.
 696                                  * Reserve it for the originals.
 697                                  * If we never find another we save a copy.
 698                                  */
 699                                 firstLink = destLink;
 700                                 continue;
 701                         }
 702
 703                         /*
 704                          * It's usable link but not the reserved (first) one.
 705                          * Copy mbuf info for sending.
 706                          */
 707                         m2 = m_dup(m, M_DONTWAIT);      /* XXX m_copypacket() */
 708                         if (m2 == NULL) {
 709                                 link->stats.memoryFailures++;
 710                                 NG_FREE_ITEM(item);
 711                                 NG_FREE_M(m);
 712                                 return (ENOBUFS);
 713                         }
 714                 }
 715
 716                 /* Update stats */
 717                 destLink->stats.xmitPackets++;
 718                 destLink->stats.xmitOctets += m->m_pkthdr.len;
 719                 switch (manycast) {
 720                 case 0:                                 /* unicast */
 721                         break;
 722                 case 1:                                 /* multicast */
 723                         destLink->stats.xmitMulticasts++;
 724                         break;
 725                 case 2:                                 /* broadcast */
 726                         destLink->stats.xmitBroadcasts++;
 727                         break;
 728                 }
 729
 730                 /* Send packet */
 731                 if (destLink == firstLink) {
 732                         /*
 733                          * If we've sent all the others, send the original
 734                          * on the first link we found.
 735                          */
 736                         NG_FWD_NEW_DATA(error, item, destLink->hook, m);
 737                         break; /* always done last - not really needed. */
 738                 } else {
 739                         NG_SEND_DATA_ONLY(error, destLink->hook, m2);
 740                 }
 741         }
 742         return (error);
 743 }
 744
 745 /*
 746  * Shutdown node
 747  */
 748 static int
 749 ng_bridge_shutdown(node_p node)
 750 {
 751         const priv_p priv = NG_NODE_PRIVATE(node);
 752
 753         /*
 754          * Shut down everything except the timer. There's no way to
 755          * avoid another possible timeout event (it may have already
 756          * been dequeued), so we can't free the node yet.
 757          */
 758         KASSERT(priv->numLinks == 0 && priv->numHosts == 0,
 759             ("%s: numLinks=%d numHosts=%d",
 760             __func__, priv->numLinks, priv->numHosts));
 761         FREE(priv->tab, M_NETGRAPH_BRIDGE);
 762
 763         /* NGF_INVALID flag is now set so node will be freed at next timeout */
 764         return (0);
 765 }
 766
 767 /*
 768  * Hook disconnection.
 769  */
 770 static int
 771 ng_bridge_disconnect(hook_p hook)
 772 {
 773         const priv_p priv = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
 774         int linkNum;
 775
 776         /* Get link number */
 777         linkNum = (intptr_t)NG_HOOK_PRIVATE(hook);
 778         KASSERT(linkNum >= 0 && linkNum < NG_BRIDGE_MAX_LINKS,
 779             ("%s: linkNum=%u", __func__, linkNum));
 780
 781         /* Remove all hosts associated with this link */
 782         ng_bridge_remove_hosts(priv, linkNum);
 783
 784         /* Free associated link information */
 785         KASSERT(priv->links[linkNum] != NULL, ("%s: no link", __func__));
 786         FREE(priv->links[linkNum], M_NETGRAPH_BRIDGE);
 787         priv->links[linkNum] = NULL;
 788         priv->numLinks--;
 789
 790         /* If no more hooks, go away */
 791         if ((NG_NODE_NUMHOOKS(NG_HOOK_NODE(hook)) == 0)
 792         && (NG_NODE_IS_VALID(NG_HOOK_NODE(hook)))) {
 793                 ng_rmnode_self(NG_HOOK_NODE(hook));
 794         }
 795         return (0);
 796 }
 797
 798 /******************************************************************
 799                     HASH TABLE FUNCTIONS
 800 ******************************************************************/
 801
 802 /*
 803  * Hash algorithm
 804  */
 805 #define HASH(addr,mask)         ( (((const u_int16_t *)(addr))[0]       \
 806                                  ^ ((const u_int16_t *)(addr))[1]       \
 807                                  ^ ((const u_int16_t *)(addr))[2]) & (mask) )
 808
 809 /*
 810  * Find a host entry in the table.
 811  */
 812 static struct ng_bridge_host *
 813 ng_bridge_get(priv_p priv, const u_char *addr)
 814 {
 815         const int bucket = HASH(addr, priv->hashMask);
 816         struct ng_bridge_hent *hent;
 817
 818         SLIST_FOREACH(hent, &priv->tab[bucket], next) {
 819                 if (ETHER_EQUAL(hent->host.addr, addr))
 820                         return (&hent->host);
 821         }
 822         return (NULL);
 823 }
 824
 825 /*
 826  * Add a new host entry to the table. This assumes the host doesn't
 827  * already exist in the table. Returns 1 on success, 0 if there
 828  * was a memory allocation failure.
 829  */
 830 static int
 831 ng_bridge_put(priv_p priv, const u_char *addr, int linkNum)
 832 {
 833         const int bucket = HASH(addr, priv->hashMask);
 834         struct ng_bridge_hent *hent;
 835
 836 #ifdef INVARIANTS
 837         /* Assert that entry does not already exist in hashtable */
 838         SLIST_FOREACH(hent, &priv->tab[bucket], next) {
 839                 KASSERT(!ETHER_EQUAL(hent->host.addr, addr),
 840                     ("%s: entry %6D exists in table", __func__, addr, ":"));
 841         }
 842 #endif
 843
 844         /* Allocate and initialize new hashtable entry */
 845         MALLOC(hent, struct ng_bridge_hent *,
 846             sizeof(*hent), M_NETGRAPH_BRIDGE, M_NOWAIT);
 847         if (hent == NULL)
 848                 return (0);
 849         bcopy(addr, hent->host.addr, ETHER_ADDR_LEN);
 850         hent->host.linkNum = linkNum;
 851         hent->host.staleness = 0;
 852         hent->host.age = 0;
 853
 854         /* Add new element to hash bucket */
 855         SLIST_INSERT_HEAD(&priv->tab[bucket], hent, next);
 856         priv->numHosts++;
 857
 858         /* Resize table if necessary */
 859         ng_bridge_rehash(priv);
 860         return (1);
 861 }
 862
 863 /*
 864  * Resize the hash table. We try to maintain the number of buckets
 865  * such that the load factor is in the range 0.25 to 1.0.
 866  *
 867  * If we can't get the new memory then we silently fail. This is OK
 868  * because things will still work and we'll try again soon anyway.
 869  */
 870 static void
 871 ng_bridge_rehash(priv_p priv)
 872 {
 873         struct ng_bridge_bucket *newTab;
 874         int oldBucket, newBucket;
 875         int newNumBuckets;
 876         u_int newMask;
 877
 878         /* Is table too full or too empty? */
 879         if (priv->numHosts > priv->numBuckets
 880             && (priv->numBuckets << 1) <= MAX_BUCKETS)
 881                 newNumBuckets = priv->numBuckets << 1;
 882         else if (priv->numHosts < (priv->numBuckets >> 2)
 883             && (priv->numBuckets >> 2) >= MIN_BUCKETS)
 884                 newNumBuckets = priv->numBuckets >> 2;
 885         else
 886                 return;
 887         newMask = newNumBuckets - 1;
 888
 889         /* Allocate and initialize new table */
 890         MALLOC(newTab, struct ng_bridge_bucket *,
 891             newNumBuckets * sizeof(*newTab), M_NETGRAPH_BRIDGE, M_NOWAIT | M_ZERO);
 892         if (newTab == NULL)
 893                 return;
 894
 895         /* Move all entries from old table to new table */
 896         for (oldBucket = 0; oldBucket < priv->numBuckets; oldBucket++) {
 897                 struct ng_bridge_bucket *const oldList = &priv->tab[oldBucket];
 898
 899                 while (!SLIST_EMPTY(oldList)) {
 900                         struct ng_bridge_hent *const hent
 901                             = SLIST_FIRST(oldList);
 902
 903                         SLIST_REMOVE_HEAD(oldList, next);
 904                         newBucket = HASH(hent->host.addr, newMask);
 905                         SLIST_INSERT_HEAD(&newTab[newBucket], hent, next);
 906                 }
 907         }
 908
 909         /* Replace old table with new one */
 910         if (priv->conf.debugLevel >= 3) {
 911                 log(LOG_INFO, "ng_bridge: %s: table size %d -> %d\n",
 912                     ng_bridge_nodename(priv->node),
 913                     priv->numBuckets, newNumBuckets);
 914         }
 915         FREE(priv->tab, M_NETGRAPH_BRIDGE);
 916         priv->numBuckets = newNumBuckets;
 917         priv->hashMask = newMask;
 918         priv->tab = newTab;
 919         return;
 920 }
 921
 922 /******************************************************************
 923                     MISC FUNCTIONS
 924 ******************************************************************/
 925
 926 /*
 927  * Remove all hosts associated with a specific link from the hashtable.
 928  * If linkNum == -1, then remove all hosts in the table.
 929  */
 930 static void
 931 ng_bridge_remove_hosts(priv_p priv, int linkNum)
 932 {
 933         int bucket;
 934
 935         for (bucket = 0; bucket < priv->numBuckets; bucket++) {
 936                 struct ng_bridge_hent **hptr = &SLIST_FIRST(&priv->tab[bucket]);
 937
 938                 while (*hptr != NULL) {
 939                         struct ng_bridge_hent *const hent = *hptr;
 940
 941                         if (linkNum == -1 || hent->host.linkNum == linkNum) {
 942                                 *hptr = SLIST_NEXT(hent, next);
 943                                 FREE(hent, M_NETGRAPH_BRIDGE);
 944                                 priv->numHosts--;
 945                         } else
 946                                 hptr = &SLIST_NEXT(hent, next);
 947                 }
 948         }
 949 }
 950
 951 /*
 952  * Handle our once-per-second timeout event. We do two things:
 953  * we decrement link->loopCount for those links being muted due to
 954  * a detected loopback condition, and we remove any hosts from
 955  * the hashtable whom we haven't heard from in a long while.
 956  *
 957  * If the node has the NGF_INVALID flag set, our job is to kill it.
 958  */
 959 static void
 960 ng_bridge_timeout(void *arg)
 961 {
 962         const node_p node = arg;
 963         const priv_p priv = NG_NODE_PRIVATE(node);
 964         int s, bucket;
 965         int counter = 0;
 966         int linkNum;
 967
 968         /* If node was shut down, this is the final lingering timeout */
 969         s = splnet();
 970         if (NG_NODE_NOT_VALID(node)) {
 971                 FREE(priv, M_NETGRAPH_BRIDGE);
 972                 NG_NODE_SET_PRIVATE(node, NULL);
 973                 NG_NODE_UNREF(node);
 974                 splx(s);
 975                 return;
 976         }
 977
 978         /* Register a new timeout, keeping the existing node reference */
 979         callout_reset(&priv->timer, hz, ng_bridge_timeout, node);
 980
 981         /* Update host time counters and remove stale entries */
 982         for (bucket = 0; bucket < priv->numBuckets; bucket++) {
 983                 struct ng_bridge_hent **hptr = &SLIST_FIRST(&priv->tab[bucket]);
 984
 985                 while (*hptr != NULL) {
 986                         struct ng_bridge_hent *const hent = *hptr;
 987
 988                         /* Make sure host's link really exists */
 989                         KASSERT(priv->links[hent->host.linkNum] != NULL,
 990                             ("%s: host %6D on nonexistent link %d\n",
 991                             __func__, hent->host.addr, ":",
 992                             hent->host.linkNum));
 993
 994                         /* Remove hosts we haven't heard from in a while */
 995                         if (++hent->host.staleness >= priv->conf.maxStaleness) {
 996                                 *hptr = SLIST_NEXT(hent, next);
 997                                 FREE(hent, M_NETGRAPH_BRIDGE);
 998                                 priv->numHosts--;
 999                         } else {
1000                                 if (hent->host.age < 0xffff)
1001                                         hent->host.age++;
1002                                 hptr = &SLIST_NEXT(hent, next);
1003                                 counter++;
1004                         }
1005                 }
1006         }
1007         KASSERT(priv->numHosts == counter,
1008             ("%s: hosts: %d != %d", __func__, priv->numHosts, counter));
1009
1010         /* Decrease table size if necessary */
1011         ng_bridge_rehash(priv);
1012
1013         /* Decrease loop counter on muted looped back links */
1014         for (counter = linkNum = 0; linkNum < NG_BRIDGE_MAX_LINKS; linkNum++) {
1015                 struct ng_bridge_link *const link = priv->links[linkNum];
1016
1017                 if (link != NULL) {
1018                         if (link->loopCount != 0) {
1019                                 link->loopCount--;
1020                                 if (link->loopCount == 0
1021                                     && priv->conf.debugLevel >= 2) {
1022                                         log(LOG_INFO, "ng_bridge: %s:"
1023                                             " restoring looped back link%d\n",
1024                                             ng_bridge_nodename(node), linkNum);
1025                                 }
1026                         }
1027                         counter++;
1028                 }
1029         }
1030         KASSERT(priv->numLinks == counter,
1031             ("%s: links: %d != %d", __func__, priv->numLinks, counter));
1032
1033         /* Done */
1034         splx(s);
1035 }
1036
1037 /*
1038  * Return node's "name", even if it doesn't have one.
1039  */
1040 static const char *
1041 ng_bridge_nodename(node_p node)
1042 {
1043         static char name[NG_NODESIZ];
1044
1045         if (NG_NODE_NAME(node) != NULL)
1046                 snprintf(name, sizeof(name), "%s", NG_NODE_NAME(node));
1047         else
1048                 snprintf(name, sizeof(name), "[%x]", ng_node2ID(node));
1049         return name;
1050 }
1051