sys/netgraph7/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: src/sys/netgraph/ng_bridge.c,v 1.31 2005/02/09 15:14:44 ru Exp $
  41  */
  42
  43 /*
  44  * ng_bridge(4) netgraph node type
  45  *
  46  * The node performs standard intelligent Ethernet bridging over
  47  * each of its connected hooks, or links.  A simple loop detection
  48  * algorithm is included which disables a link for priv->conf.loopTimeout
  49  * seconds when a host is seen to have jumped from one link to
  50  * another within priv->conf.minStableAge seconds.
  51  *
  52  * We keep a hashtable that maps Ethernet addresses to host info,
  53  * which is contained in struct ng_bridge_host's. These structures
  54  * tell us on which link the host may be found. A host's entry will
  55  * expire after priv->conf.maxStaleness seconds.
  56  *
  57  * This node is optimzed for stable networks, where machines jump
  58  * from one port to the other only rarely.
  59  */
  60
  61 #include <sys/param.h>
  62 #include <sys/systm.h>
  63 #include <sys/kernel.h>
  64 #include <sys/malloc.h>
  65 #include <sys/mbuf.h>
  66 #include <sys/errno.h>
  67 #include <sys/syslog.h>
  68 #include <sys/socket.h>
  69 #include <sys/ctype.h>
  70
  71 #include <net/if.h>
  72 #include <net/ethernet.h>
  73
  74 #include <netinet/in.h>
  75 #include <netinet/ip_fw.h>
  76
  77 #include <netgraph/ng_message.h>
  78 #include <netgraph/netgraph.h>
  79 #include <netgraph/ng_parse.h>
  80 #include <netgraph/ng_bridge.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(node_p node, hook_p hook, void *arg1, int arg2);
 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_field ng_bridge_host_type_fields[]
 175         = NG_BRIDGE_HOST_TYPE_INFO(&ng_parse_enaddr_type);
 176 static const struct ng_parse_type ng_bridge_host_type = {
 177         &ng_parse_struct_type,
 178         &ng_bridge_host_type_fields
 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_field ng_bridge_host_ary_type_fields[]
 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_fields
 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_field ng_bridge_config_type_fields[]
 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_fields
 209 };
 210
 211 /* Parse type for struct ng_bridge_link_stat */
 212 static const struct ng_parse_struct_field ng_bridge_stats_type_fields[]
 213         = 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_fields
 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         .version =      NG_ABI_VERSION,
 276         .name =         NG_BRIDGE_NODE_TYPE,
 277         .constructor =  ng_bridge_constructor,
 278         .rcvmsg =       ng_bridge_rcvmsg,
 279         .shutdown =     ng_bridge_shutdown,
 280         .newhook =      ng_bridge_newhook,
 281         .rcvdata =      ng_bridge_rcvdata,
 282         .disconnect =   ng_bridge_disconnect,
 283         .cmdlist =      ng_bridge_cmdlist,
 284 };
 285 NETGRAPH_INIT(bridge, &ng_bridge_typestruct);
 286
 287 /******************************************************************
 288                     NETGRAPH NODE METHODS
 289 ******************************************************************/
 290
 291 /*
 292  * Node constructor
 293  */
 294 static int
 295 ng_bridge_constructor(node_p node)
 296 {
 297         priv_p priv;
 298
 299         /* Allocate and initialize private info */
 300         MALLOC(priv, priv_p, sizeof(*priv), M_NETGRAPH_BRIDGE, M_NOWAIT | M_ZERO);
 301         if (priv == NULL)
 302                 return (ENOMEM);
 303         ng_callout_init(&priv->timer);
 304
 305         /* Allocate and initialize hash table, etc. */
 306         MALLOC(priv->tab, struct ng_bridge_bucket *,
 307             MIN_BUCKETS * sizeof(*priv->tab), M_NETGRAPH_BRIDGE, M_NOWAIT | M_ZERO);
 308         if (priv->tab == NULL) {
 309                 FREE(priv, M_NETGRAPH_BRIDGE);
 310                 return (ENOMEM);
 311         }
 312         priv->numBuckets = MIN_BUCKETS;
 313         priv->hashMask = MIN_BUCKETS - 1;
 314         priv->conf.debugLevel = 1;
 315         priv->conf.loopTimeout = DEFAULT_LOOP_TIMEOUT;
 316         priv->conf.maxStaleness = DEFAULT_MAX_STALENESS;
 317         priv->conf.minStableAge = DEFAULT_MIN_STABLE_AGE;
 318
 319         /*
 320          * This node has all kinds of stuff that could be screwed by SMP.
 321          * Until it gets it's own internal protection, we go through in
 322          * single file. This could hurt a machine bridging beteen two
 323          * GB ethernets so it should be fixed.
 324          * When it's fixed the process SHOULD NOT SLEEP, spinlocks please!
 325          * (and atomic ops )
 326          */
 327         NG_NODE_FORCE_WRITER(node);
 328         NG_NODE_SET_PRIVATE(node, priv);
 329         priv->node = node;
 330
 331         /* Start timer; timer is always running while node is alive */
 332         ng_callout(&priv->timer, node, NULL, hz, ng_bridge_timeout, NULL, 0);
 333
 334         /* Done */
 335         return (0);
 336 }
 337
 338 /*
 339  * Method for attaching a new hook
 340  */
 341 static  int
 342 ng_bridge_newhook(node_p node, hook_p hook, const char *name)
 343 {
 344         const priv_p priv = NG_NODE_PRIVATE(node);
 345
 346         /* Check for a link hook */
 347         if (strncmp(name, NG_BRIDGE_HOOK_LINK_PREFIX,
 348             strlen(NG_BRIDGE_HOOK_LINK_PREFIX)) == 0) {
 349                 const char *cp;
 350                 char *eptr;
 351                 u_long linkNum;
 352
 353                 cp = name + strlen(NG_BRIDGE_HOOK_LINK_PREFIX);
 354                 if (!isdigit(*cp) || (cp[0] == '0' && cp[1] != '\0'))
 355                         return (EINVAL);
 356                 linkNum = strtoul(cp, &eptr, 10);
 357                 if (*eptr != '\0' || linkNum >= NG_BRIDGE_MAX_LINKS)
 358                         return (EINVAL);
 359                 if (priv->links[linkNum] != NULL)
 360                         return (EISCONN);
 361                 MALLOC(priv->links[linkNum], struct ng_bridge_link *,
 362                     sizeof(*priv->links[linkNum]), M_NETGRAPH_BRIDGE, M_NOWAIT|M_ZERO);
 363                 if (priv->links[linkNum] == NULL)
 364                         return (ENOMEM);
 365                 priv->links[linkNum]->hook = hook;
 366                 NG_HOOK_SET_PRIVATE(hook, (void *)linkNum);
 367                 priv->numLinks++;
 368                 return (0);
 369         }
 370
 371         /* Unknown hook name */
 372         return (EINVAL);
 373 }
 374
 375 /*
 376  * Receive a control message
 377  */
 378 static int
 379 ng_bridge_rcvmsg(node_p node, item_p item, hook_p lasthook)
 380 {
 381         const priv_p priv = NG_NODE_PRIVATE(node);
 382         struct ng_mesg *resp = NULL;
 383         int error = 0;
 384         struct ng_mesg *msg;
 385
 386         NGI_GET_MSG(item, msg);
 387         switch (msg->header.typecookie) {
 388         case NGM_BRIDGE_COOKIE:
 389                 switch (msg->header.cmd) {
 390                 case NGM_BRIDGE_GET_CONFIG:
 391                     {
 392                         struct ng_bridge_config *conf;
 393
 394                         NG_MKRESPONSE(resp, msg,
 395                             sizeof(struct ng_bridge_config), M_NOWAIT);
 396                         if (resp == NULL) {
 397                                 error = ENOMEM;
 398                                 break;
 399                         }
 400                         conf = (struct ng_bridge_config *)resp->data;
 401                         *conf = priv->conf;     /* no sanity checking needed */
 402                         break;
 403                     }
 404                 case NGM_BRIDGE_SET_CONFIG:
 405                     {
 406                         struct ng_bridge_config *conf;
 407                         int i;
 408
 409                         if (msg->header.arglen
 410                             != sizeof(struct ng_bridge_config)) {
 411                                 error = EINVAL;
 412                                 break;
 413                         }
 414                         conf = (struct ng_bridge_config *)msg->data;
 415                         priv->conf = *conf;
 416                         for (i = 0; i < NG_BRIDGE_MAX_LINKS; i++)
 417                                 priv->conf.ipfw[i] = !!priv->conf.ipfw[i];
 418                         break;
 419                     }
 420                 case NGM_BRIDGE_RESET:
 421                     {
 422                         int i;
 423
 424                         /* Flush all entries in the hash table */
 425                         ng_bridge_remove_hosts(priv, -1);
 426
 427                         /* Reset all loop detection counters and stats */
 428                         for (i = 0; i < NG_BRIDGE_MAX_LINKS; i++) {
 429                                 if (priv->links[i] == NULL)
 430                                         continue;
 431                                 priv->links[i]->loopCount = 0;
 432                                 bzero(&priv->links[i]->stats,
 433                                     sizeof(priv->links[i]->stats));
 434                         }
 435                         break;
 436                     }
 437                 case NGM_BRIDGE_GET_STATS:
 438                 case NGM_BRIDGE_CLR_STATS:
 439                 case NGM_BRIDGE_GETCLR_STATS:
 440                     {
 441                         struct ng_bridge_link *link;
 442                         int linkNum;
 443
 444                         /* Get link number */
 445                         if (msg->header.arglen != sizeof(u_int32_t)) {
 446                                 error = EINVAL;
 447                                 break;
 448                         }
 449                         linkNum = *((u_int32_t *)msg->data);
 450                         if (linkNum < 0 || linkNum >= NG_BRIDGE_MAX_LINKS) {
 451                                 error = EINVAL;
 452                                 break;
 453                         }
 454                         if ((link = priv->links[linkNum]) == NULL) {
 455                                 error = ENOTCONN;
 456                                 break;
 457                         }
 458
 459                         /* Get/clear stats */
 460                         if (msg->header.cmd != NGM_BRIDGE_CLR_STATS) {
 461                                 NG_MKRESPONSE(resp, msg,
 462                                     sizeof(link->stats), M_NOWAIT);
 463                                 if (resp == NULL) {
 464                                         error = ENOMEM;
 465                                         break;
 466                                 }
 467                                 bcopy(&link->stats,
 468                                     resp->data, sizeof(link->stats));
 469                         }
 470                         if (msg->header.cmd != NGM_BRIDGE_GET_STATS)
 471                                 bzero(&link->stats, sizeof(link->stats));
 472                         break;
 473                     }
 474                 case NGM_BRIDGE_GET_TABLE:
 475                     {
 476                         struct ng_bridge_host_ary *ary;
 477                         struct ng_bridge_hent *hent;
 478                         int i = 0, bucket;
 479
 480                         NG_MKRESPONSE(resp, msg, sizeof(*ary)
 481                             + (priv->numHosts * sizeof(*ary->hosts)), M_NOWAIT);
 482                         if (resp == NULL) {
 483                                 error = ENOMEM;
 484                                 break;
 485                         }
 486                         ary = (struct ng_bridge_host_ary *)resp->data;
 487                         ary->numHosts = priv->numHosts;
 488                         for (bucket = 0; bucket < priv->numBuckets; bucket++) {
 489                                 SLIST_FOREACH(hent, &priv->tab[bucket], next)
 490                                         ary->hosts[i++] = hent->host;
 491                         }
 492                         break;
 493                     }
 494                 default:
 495                         error = EINVAL;
 496                         break;
 497                 }
 498                 break;
 499         default:
 500                 error = EINVAL;
 501                 break;
 502         }
 503
 504         /* Done */
 505         NG_RESPOND_MSG(error, node, item, resp);
 506         NG_FREE_MSG(msg);
 507         return (error);
 508 }
 509
 510 /*
 511  * Receive data on a hook
 512  */
 513 static int
 514 ng_bridge_rcvdata(hook_p hook, item_p item)
 515 {
 516         const node_p node = NG_HOOK_NODE(hook);
 517         const priv_p priv = NG_NODE_PRIVATE(node);
 518         struct ng_bridge_host *host;
 519         struct ng_bridge_link *link;
 520         struct ether_header *eh;
 521         int error = 0, linkNum, linksSeen;
 522         int manycast;
 523         struct mbuf *m;
 524         struct ng_bridge_link *firstLink;
 525
 526         NGI_GET_M(item, m);
 527         /* Get link number */
 528         linkNum = (intptr_t)NG_HOOK_PRIVATE(hook);
 529         KASSERT(linkNum >= 0 && linkNum < NG_BRIDGE_MAX_LINKS,
 530             ("%s: linkNum=%u", __func__, linkNum));
 531         link = priv->links[linkNum];
 532         KASSERT(link != NULL, ("%s: link%d null", __func__, linkNum));
 533
 534         /* Sanity check packet and pull up header */
 535         if (m->m_pkthdr.len < ETHER_HDR_LEN) {
 536                 link->stats.recvRunts++;
 537                 NG_FREE_ITEM(item);
 538                 NG_FREE_M(m);
 539                 return (EINVAL);
 540         }
 541         if (m->m_len < ETHER_HDR_LEN && !(m = m_pullup(m, ETHER_HDR_LEN))) {
 542                 link->stats.memoryFailures++;
 543                 NG_FREE_ITEM(item);
 544                 return (ENOBUFS);
 545         }
 546         eh = mtod(m, struct ether_header *);
 547         if ((eh->ether_shost[0] & 1) != 0) {
 548                 link->stats.recvInvalid++;
 549                 NG_FREE_ITEM(item);
 550                 NG_FREE_M(m);
 551                 return (EINVAL);
 552         }
 553
 554         /* Is link disabled due to a loopback condition? */
 555         if (link->loopCount != 0) {
 556                 link->stats.loopDrops++;
 557                 NG_FREE_ITEM(item);
 558                 NG_FREE_M(m);
 559                 return (ELOOP);         /* XXX is this an appropriate error? */
 560         }
 561
 562         /* Update stats */
 563         link->stats.recvPackets++;
 564         link->stats.recvOctets += m->m_pkthdr.len;
 565         if ((manycast = (eh->ether_dhost[0] & 1)) != 0) {
 566                 if (ETHER_EQUAL(eh->ether_dhost, ng_bridge_bcast_addr)) {
 567                         link->stats.recvBroadcasts++;
 568                         manycast = 2;
 569                 } else
 570                         link->stats.recvMulticasts++;
 571         }
 572
 573         /* Look up packet's source Ethernet address in hashtable */
 574         if ((host = ng_bridge_get(priv, eh->ether_shost)) != NULL) {
 575
 576                 /* Update time since last heard from this host */
 577                 host->staleness = 0;
 578
 579                 /* Did host jump to a different link? */
 580                 if (host->linkNum != linkNum) {
 581
 582                         /*
 583                          * If the host's old link was recently established
 584                          * on the old link and it's already jumped to a new
 585                          * link, declare a loopback condition.
 586                          */
 587                         if (host->age < priv->conf.minStableAge) {
 588
 589                                 /* Log the problem */
 590                                 if (priv->conf.debugLevel >= 2) {
 591                                         struct ifnet *ifp = m->m_pkthdr.rcvif;
 592                                         char suffix[32];
 593
 594                                         if (ifp != NULL)
 595                                                 snprintf(suffix, sizeof(suffix),
 596                                                     " (%s)", ifp->if_xname);
 597                                         else
 598                                                 *suffix = '\0';
 599                                         log(LOG_WARNING, "ng_bridge: %s:"
 600                                             " loopback detected on %s%s\n",
 601                                             ng_bridge_nodename(node),
 602                                             NG_HOOK_NAME(hook), suffix);
 603                                 }
 604
 605                                 /* Mark link as linka non grata */
 606                                 link->loopCount = priv->conf.loopTimeout;
 607                                 link->stats.loopDetects++;
 608
 609                                 /* Forget all hosts on this link */
 610                                 ng_bridge_remove_hosts(priv, linkNum);
 611
 612                                 /* Drop packet */
 613                                 link->stats.loopDrops++;
 614                                 NG_FREE_ITEM(item);
 615                                 NG_FREE_M(m);
 616                                 return (ELOOP);         /* XXX appropriate? */
 617                         }
 618
 619                         /* Move host over to new link */
 620                         host->linkNum = linkNum;
 621                         host->age = 0;
 622                 }
 623         } else {
 624                 if (!ng_bridge_put(priv, eh->ether_shost, linkNum)) {
 625                         link->stats.memoryFailures++;
 626                         NG_FREE_ITEM(item);
 627                         NG_FREE_M(m);
 628                         return (ENOMEM);
 629                 }
 630         }
 631
 632         /* Run packet through ipfw processing, if enabled */
 633 #if 0
 634         if (priv->conf.ipfw[linkNum] && fw_enable && ip_fw_chk_ptr != NULL) {
 635                 /* XXX not implemented yet */
 636         }
 637 #endif
 638
 639         /*
 640          * If unicast and destination host known, deliver to host's link,
 641          * unless it is the same link as the packet came in on.
 642          */
 643         if (!manycast) {
 644
 645                 /* Determine packet destination link */
 646                 if ((host = ng_bridge_get(priv, eh->ether_dhost)) != NULL) {
 647                         struct ng_bridge_link *const destLink
 648                             = priv->links[host->linkNum];
 649
 650                         /* If destination same as incoming link, do nothing */
 651                         KASSERT(destLink != NULL,
 652                             ("%s: link%d null", __func__, host->linkNum));
 653                         if (destLink == link) {
 654                                 NG_FREE_ITEM(item);
 655                                 NG_FREE_M(m);
 656                                 return (0);
 657                         }
 658
 659                         /* Deliver packet out the destination link */
 660                         destLink->stats.xmitPackets++;
 661                         destLink->stats.xmitOctets += m->m_pkthdr.len;
 662                         NG_FWD_NEW_DATA(error, item, destLink->hook, m);
 663                         return (error);
 664                 }
 665
 666                 /* Destination host is not known */
 667                 link->stats.recvUnknown++;
 668         }
 669
 670         /* Distribute unknown, multicast, broadcast pkts to all other links */
 671         firstLink = NULL;
 672         for (linkNum = linksSeen = 0; linksSeen <= priv->numLinks; linkNum++) {
 673                 struct ng_bridge_link *destLink;
 674                 struct mbuf *m2 = NULL;
 675
 676                 /*
 677                  * If we have checked all the links then now
 678                  * send the original on its reserved link
 679                  */
 680                 if (linksSeen == priv->numLinks) {
 681                         /* If we never saw a good link, leave. */
 682                         if (firstLink == NULL) {
 683                                 NG_FREE_ITEM(item);
 684                                 NG_FREE_M(m);
 685                                 return (0);
 686                         }
 687                         destLink = firstLink;
 688                 } else {
 689                         destLink = priv->links[linkNum];
 690                         if (destLink != NULL)
 691                                 linksSeen++;
 692                         /* Skip incoming link and disconnected links */
 693                         if (destLink == NULL || destLink == link) {
 694                                 continue;
 695                         }
 696                         if (firstLink == NULL) {
 697                                 /*
 698                                  * This is the first usable link we have found.
 699                                  * Reserve it for the originals.
 700                                  * If we never find another we save a copy.
 701                                  */
 702                                 firstLink = destLink;
 703                                 continue;
 704                         }
 705
 706                         /*
 707                          * It's usable link but not the reserved (first) one.
 708                          * Copy mbuf info for sending.
 709                          */
 710                         m2 = m_dup(m, M_DONTWAIT);      /* XXX m_copypacket() */
 711                         if (m2 == NULL) {
 712                                 link->stats.memoryFailures++;
 713                                 NG_FREE_ITEM(item);
 714                                 NG_FREE_M(m);
 715                                 return (ENOBUFS);
 716                         }
 717                 }
 718
 719                 /* Update stats */
 720                 destLink->stats.xmitPackets++;
 721                 destLink->stats.xmitOctets += m->m_pkthdr.len;
 722                 switch (manycast) {
 723                 case 0:                                 /* unicast */
 724                         break;
 725                 case 1:                                 /* multicast */
 726                         destLink->stats.xmitMulticasts++;
 727                         break;
 728                 case 2:                                 /* broadcast */
 729                         destLink->stats.xmitBroadcasts++;
 730                         break;
 731                 }
 732
 733                 /* Send packet */
 734                 if (destLink == firstLink) {
 735                         /*
 736                          * If we've sent all the others, send the original
 737                          * on the first link we found.
 738                          */
 739                         NG_FWD_NEW_DATA(error, item, destLink->hook, m);
 740                         break; /* always done last - not really needed. */
 741                 } else {
 742                         NG_SEND_DATA_ONLY(error, destLink->hook, m2);
 743                 }
 744         }
 745         return (error);
 746 }
 747
 748 /*
 749  * Shutdown node
 750  */
 751 static int
 752 ng_bridge_shutdown(node_p node)
 753 {
 754         const priv_p priv = NG_NODE_PRIVATE(node);
 755
 756         /*
 757          * Shut down everything including the timer.  Even if the
 758          * callout has already been dequeued and is about to be
 759          * run, ng_bridge_timeout() won't be fired as the node
 760          * is already marked NGF_INVALID, so we're safe to free
 761          * the node now.
 762          */
 763         KASSERT(priv->numLinks == 0 && priv->numHosts == 0,
 764             ("%s: numLinks=%d numHosts=%d",
 765             __func__, priv->numLinks, priv->numHosts));
 766         ng_uncallout(&priv->timer, node);
 767         NG_NODE_SET_PRIVATE(node, NULL);
 768         NG_NODE_UNREF(node);
 769         FREE(priv->tab, M_NETGRAPH_BRIDGE);
 770         FREE(priv, M_NETGRAPH_BRIDGE);
 771         return (0);
 772 }
 773
 774 /*
 775  * Hook disconnection.
 776  */
 777 static int
 778 ng_bridge_disconnect(hook_p hook)
 779 {
 780         const priv_p priv = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
 781         int linkNum;
 782
 783         /* Get link number */
 784         linkNum = (intptr_t)NG_HOOK_PRIVATE(hook);
 785         KASSERT(linkNum >= 0 && linkNum < NG_BRIDGE_MAX_LINKS,
 786             ("%s: linkNum=%u", __func__, linkNum));
 787
 788         /* Remove all hosts associated with this link */
 789         ng_bridge_remove_hosts(priv, linkNum);
 790
 791         /* Free associated link information */
 792         KASSERT(priv->links[linkNum] != NULL, ("%s: no link", __func__));
 793         FREE(priv->links[linkNum], M_NETGRAPH_BRIDGE);
 794         priv->links[linkNum] = NULL;
 795         priv->numLinks--;
 796
 797         /* If no more hooks, go away */
 798         if ((NG_NODE_NUMHOOKS(NG_HOOK_NODE(hook)) == 0)
 799         && (NG_NODE_IS_VALID(NG_HOOK_NODE(hook)))) {
 800                 ng_rmnode_self(NG_HOOK_NODE(hook));
 801         }
 802         return (0);
 803 }
 804
 805 /******************************************************************
 806                     HASH TABLE FUNCTIONS
 807 ******************************************************************/
 808
 809 /*
 810  * Hash algorithm
 811  */
 812 #define HASH(addr,mask)         ( (((const u_int16_t *)(addr))[0]       \
 813                                  ^ ((const u_int16_t *)(addr))[1]       \
 814                                  ^ ((const u_int16_t *)(addr))[2]) & (mask) )
 815
 816 /*
 817  * Find a host entry in the table.
 818  */
 819 static struct ng_bridge_host *
 820 ng_bridge_get(priv_p priv, const u_char *addr)
 821 {
 822         const int bucket = HASH(addr, priv->hashMask);
 823         struct ng_bridge_hent *hent;
 824
 825         SLIST_FOREACH(hent, &priv->tab[bucket], next) {
 826                 if (ETHER_EQUAL(hent->host.addr, addr))
 827                         return (&hent->host);
 828         }
 829         return (NULL);
 830 }
 831
 832 /*
 833  * Add a new host entry to the table. This assumes the host doesn't
 834  * already exist in the table. Returns 1 on success, 0 if there
 835  * was a memory allocation failure.
 836  */
 837 static int
 838 ng_bridge_put(priv_p priv, const u_char *addr, int linkNum)
 839 {
 840         const int bucket = HASH(addr, priv->hashMask);
 841         struct ng_bridge_hent *hent;
 842
 843 #ifdef INVARIANTS
 844         /* Assert that entry does not already exist in hashtable */
 845         SLIST_FOREACH(hent, &priv->tab[bucket], next) {
 846                 KASSERT(!ETHER_EQUAL(hent->host.addr, addr),
 847                     ("%s: entry %6D exists in table", __func__, addr, ":"));
 848         }
 849 #endif
 850
 851         /* Allocate and initialize new hashtable entry */
 852         MALLOC(hent, struct ng_bridge_hent *,
 853             sizeof(*hent), M_NETGRAPH_BRIDGE, M_NOWAIT);
 854         if (hent == NULL)
 855                 return (0);
 856         bcopy(addr, hent->host.addr, ETHER_ADDR_LEN);
 857         hent->host.linkNum = linkNum;
 858         hent->host.staleness = 0;
 859         hent->host.age = 0;
 860
 861         /* Add new element to hash bucket */
 862         SLIST_INSERT_HEAD(&priv->tab[bucket], hent, next);
 863         priv->numHosts++;
 864
 865         /* Resize table if necessary */
 866         ng_bridge_rehash(priv);
 867         return (1);
 868 }
 869
 870 /*
 871  * Resize the hash table. We try to maintain the number of buckets
 872  * such that the load factor is in the range 0.25 to 1.0.
 873  *
 874  * If we can't get the new memory then we silently fail. This is OK
 875  * because things will still work and we'll try again soon anyway.
 876  */
 877 static void
 878 ng_bridge_rehash(priv_p priv)
 879 {
 880         struct ng_bridge_bucket *newTab;
 881         int oldBucket, newBucket;
 882         int newNumBuckets;
 883         u_int newMask;
 884
 885         /* Is table too full or too empty? */
 886         if (priv->numHosts > priv->numBuckets
 887             && (priv->numBuckets << 1) <= MAX_BUCKETS)
 888                 newNumBuckets = priv->numBuckets << 1;
 889         else if (priv->numHosts < (priv->numBuckets >> 2)
 890             && (priv->numBuckets >> 2) >= MIN_BUCKETS)
 891                 newNumBuckets = priv->numBuckets >> 2;
 892         else
 893                 return;
 894         newMask = newNumBuckets - 1;
 895
 896         /* Allocate and initialize new table */
 897         MALLOC(newTab, struct ng_bridge_bucket *,
 898             newNumBuckets * sizeof(*newTab), M_NETGRAPH_BRIDGE, M_NOWAIT | M_ZERO);
 899         if (newTab == NULL)
 900                 return;
 901
 902         /* Move all entries from old table to new table */
 903         for (oldBucket = 0; oldBucket < priv->numBuckets; oldBucket++) {
 904                 struct ng_bridge_bucket *const oldList = &priv->tab[oldBucket];
 905
 906                 while (!SLIST_EMPTY(oldList)) {
 907                         struct ng_bridge_hent *const hent
 908                             = SLIST_FIRST(oldList);
 909
 910                         SLIST_REMOVE_HEAD(oldList, next);
 911                         newBucket = HASH(hent->host.addr, newMask);
 912                         SLIST_INSERT_HEAD(&newTab[newBucket], hent, next);
 913                 }
 914         }
 915
 916         /* Replace old table with new one */
 917         if (priv->conf.debugLevel >= 3) {
 918                 log(LOG_INFO, "ng_bridge: %s: table size %d -> %d\n",
 919                     ng_bridge_nodename(priv->node),
 920                     priv->numBuckets, newNumBuckets);
 921         }
 922         FREE(priv->tab, M_NETGRAPH_BRIDGE);
 923         priv->numBuckets = newNumBuckets;
 924         priv->hashMask = newMask;
 925         priv->tab = newTab;
 926         return;
 927 }
 928
 929 /******************************************************************
 930                     MISC FUNCTIONS
 931 ******************************************************************/
 932
 933 /*
 934  * Remove all hosts associated with a specific link from the hashtable.
 935  * If linkNum == -1, then remove all hosts in the table.
 936  */
 937 static void
 938 ng_bridge_remove_hosts(priv_p priv, int linkNum)
 939 {
 940         int bucket;
 941
 942         for (bucket = 0; bucket < priv->numBuckets; bucket++) {
 943                 struct ng_bridge_hent **hptr = &SLIST_FIRST(&priv->tab[bucket]);
 944
 945                 while (*hptr != NULL) {
 946                         struct ng_bridge_hent *const hent = *hptr;
 947
 948                         if (linkNum == -1 || hent->host.linkNum == linkNum) {
 949                                 *hptr = SLIST_NEXT(hent, next);
 950                                 FREE(hent, M_NETGRAPH_BRIDGE);
 951                                 priv->numHosts--;
 952                         } else
 953                                 hptr = &SLIST_NEXT(hent, next);
 954                 }
 955         }
 956 }
 957
 958 /*
 959  * Handle our once-per-second timeout event. We do two things:
 960  * we decrement link->loopCount for those links being muted due to
 961  * a detected loopback condition, and we remove any hosts from
 962  * the hashtable whom we haven't heard from in a long while.
 963  */
 964 static void
 965 ng_bridge_timeout(node_p node, hook_p hook, void *arg1, int arg2)
 966 {
 967         const priv_p priv = NG_NODE_PRIVATE(node);
 968         int bucket;
 969         int counter = 0;
 970         int linkNum;
 971
 972         /* Update host time counters and remove stale entries */
 973         for (bucket = 0; bucket < priv->numBuckets; bucket++) {
 974                 struct ng_bridge_hent **hptr = &SLIST_FIRST(&priv->tab[bucket]);
 975
 976                 while (*hptr != NULL) {
 977                         struct ng_bridge_hent *const hent = *hptr;
 978
 979                         /* Make sure host's link really exists */
 980                         KASSERT(priv->links[hent->host.linkNum] != NULL,
 981                             ("%s: host %6D on nonexistent link %d\n",
 982                             __func__, hent->host.addr, ":",
 983                             hent->host.linkNum));
 984
 985                         /* Remove hosts we haven't heard from in a while */
 986                         if (++hent->host.staleness >= priv->conf.maxStaleness) {
 987                                 *hptr = SLIST_NEXT(hent, next);
 988                                 FREE(hent, M_NETGRAPH_BRIDGE);
 989                                 priv->numHosts--;
 990                         } else {
 991                                 if (hent->host.age < 0xffff)
 992                                         hent->host.age++;
 993                                 hptr = &SLIST_NEXT(hent, next);
 994                                 counter++;
 995                         }
 996                 }
 997         }
 998         KASSERT(priv->numHosts == counter,
 999             ("%s: hosts: %d != %d", __func__, priv->numHosts, counter));
1000
1001         /* Decrease table size if necessary */
1002         ng_bridge_rehash(priv);
1003
1004         /* Decrease loop counter on muted looped back links */
1005         for (counter = linkNum = 0; linkNum < NG_BRIDGE_MAX_LINKS; linkNum++) {
1006                 struct ng_bridge_link *const link = priv->links[linkNum];
1007
1008                 if (link != NULL) {
1009                         if (link->loopCount != 0) {
1010                                 link->loopCount--;
1011                                 if (link->loopCount == 0
1012                                     && priv->conf.debugLevel >= 2) {
1013                                         log(LOG_INFO, "ng_bridge: %s:"
1014                                             " restoring looped back link%d\n",
1015                                             ng_bridge_nodename(node), linkNum);
1016                                 }
1017                         }
1018                         counter++;
1019                 }
1020         }
1021         KASSERT(priv->numLinks == counter,
1022             ("%s: links: %d != %d", __func__, priv->numLinks, counter));
1023
1024         /* Register a new timeout, keeping the existing node reference */
1025         ng_callout(&priv->timer, node, NULL, hz, ng_bridge_timeout, NULL, 0);
1026 }
1027
1028 /*
1029  * Return node's "name", even if it doesn't have one.
1030  */
1031 static const char *
1032 ng_bridge_nodename(node_p node)
1033 {
1034         static char name[NG_NODESIZ];
1035
1036         if (NG_NODE_NAME(node) != NULL)
1037                 snprintf(name, sizeof(name), "%s", NG_NODE_NAME(node));
1038         else
1039                 snprintf(name, sizeof(name), "[%x]", ng_node2ID(node));
1040         return name;
1041 }
1042