sys/netgraph/ng_bridge.c

   1 /*-
   2  * Copyright (c) 2000 Whistle Communications, Inc.
   3  * All rights reserved.
   4  *
   5  * Subject to the following obligations and disclaimer of warranty, use and
   6  * redistribution of this software, in source or object code forms, with or
   7  * without modifications are expressly permitted by Whistle Communications;
   8  * provided, however, that:
   9  * 1. Any and all reproductions of the source or object code must include the
  10  *    copyright notice above and the following disclaimer of warranties; and
  11  * 2. No rights are granted, in any manner or form, to use Whistle
  12  *    Communications, Inc. trademarks, including the mark "WHISTLE
  13  *    COMMUNICATIONS" on advertising, endorsements, or otherwise except as
  14  *    such appears in the above copyright notice or in the software.
  15  *
  16  * THIS SOFTWARE IS BEING PROVIDED BY WHISTLE COMMUNICATIONS "AS IS", AND
  17  * TO THE MAXIMUM EXTENT PERMITTED BY LAW, WHISTLE COMMUNICATIONS MAKES NO
  18  * REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED, REGARDING THIS SOFTWARE,
  19  * INCLUDING WITHOUT LIMITATION, ANY AND ALL IMPLIED WARRANTIES OF
  20  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT.
  21  * WHISTLE COMMUNICATIONS DOES NOT WARRANT, GUARANTEE, OR MAKE ANY
  22  * REPRESENTATIONS REGARDING THE USE OF, OR THE RESULTS OF THE USE OF THIS
  23  * SOFTWARE IN TERMS OF ITS CORRECTNESS, ACCURACY, RELIABILITY OR OTHERWISE.
  24  * IN NO EVENT SHALL WHISTLE COMMUNICATIONS BE LIABLE FOR ANY DAMAGES
  25  * RESULTING FROM OR ARISING OUT OF ANY USE OF THIS SOFTWARE, INCLUDING
  26  * WITHOUT LIMITATION, ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
  27  * PUNITIVE, OR CONSEQUENTIAL DAMAGES, PROCUREMENT OF SUBSTITUTE GOODS OR
  28  * SERVICES, LOSS OF USE, DATA OR PROFITS, HOWEVER CAUSED AND UNDER ANY
  29  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  30  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  31  * THIS SOFTWARE, EVEN IF WHISTLE COMMUNICATIONS IS ADVISED OF THE POSSIBILITY
  32  * OF SUCH DAMAGE.
  33  *
  34  * Author: Archie Cobbs <archie@freebsd.org>
  35  *
  36  * $FreeBSD$
  37  */
  38
  39 /*
  40  * ng_bridge(4) netgraph node type
  41  *
  42  * The node performs standard intelligent Ethernet bridging over
  43  * each of its connected hooks, or links.  A simple loop detection
  44  * algorithm is included which disables a link for priv->conf.loopTimeout
  45  * seconds when a host is seen to have jumped from one link to
  46  * another within priv->conf.minStableAge seconds.
  47  *
  48  * We keep a hashtable that maps Ethernet addresses to host info,
  49  * which is contained in struct ng_bridge_host's. These structures
  50  * tell us on which link the host may be found. A host's entry will
  51  * expire after priv->conf.maxStaleness seconds.
  52  *
  53  * This node is optimzed for stable networks, where machines jump
  54  * from one port to the other only rarely.
  55  */
  56
  57 #include <sys/param.h>
  58 #include <sys/systm.h>
  59 #include <sys/kernel.h>
  60 #include <sys/lock.h>
  61 #include <sys/malloc.h>
  62 #include <sys/mbuf.h>
  63 #include <sys/errno.h>
  64 #include <sys/rwlock.h>
  65 #include <sys/syslog.h>
  66 #include <sys/socket.h>
  67 #include <sys/ctype.h>
  68
  69 #include <net/if.h>
  70 #include <net/if_var.h>
  71 #include <net/ethernet.h>
  72 #include <net/vnet.h>
  73
  74 #include <netinet/in.h>
  75 #if 0   /* not used yet */
  76 #include <netinet/ip_fw.h>
  77 #endif
  78 #include <netgraph/ng_message.h>
  79 #include <netgraph/netgraph.h>
  80 #include <netgraph/ng_parse.h>
  81 #include <netgraph/ng_bridge.h>
  82
  83 #ifdef NG_SEPARATE_MALLOC
  84 static MALLOC_DEFINE(M_NETGRAPH_BRIDGE, "netgraph_bridge",
  85     "netgraph bridge node");
  86 #else
  87 #define M_NETGRAPH_BRIDGE M_NETGRAPH
  88 #endif
  89
  90 /* Per-link private data */
  91 struct ng_bridge_link {
  92         hook_p                          hook;           /* netgraph hook */
  93         u_int16_t                       loopCount;      /* loop ignore timer */
  94         struct ng_bridge_link_stats     stats;          /* link stats */
  95 };
  96
  97 /* Per-node private data */
  98 struct ng_bridge_private {
  99         struct ng_bridge_bucket *tab;           /* hash table bucket array */
 100         struct ng_bridge_config conf;           /* node configuration */
 101         node_p                  node;           /* netgraph node */
 102         u_int                   numHosts;       /* num entries in table */
 103         u_int                   numBuckets;     /* num buckets in table */
 104         u_int                   hashMask;       /* numBuckets - 1 */
 105         int                     numLinks;       /* num connected links */
 106         int                     persistent;     /* can exist w/o hooks */
 107         struct callout          timer;          /* one second periodic timer */
 108 };
 109 typedef struct ng_bridge_private *priv_p;
 110
 111 /* Information about a host, stored in a hash table entry */
 112 struct ng_bridge_hent {
 113         struct ng_bridge_host           host;   /* actual host info */
 114         SLIST_ENTRY(ng_bridge_hent)     next;   /* next entry in bucket */
 115 };
 116
 117 /* Hash table bucket declaration */
 118 SLIST_HEAD(ng_bridge_bucket, ng_bridge_hent);
 119
 120 /* Netgraph node methods */
 121 static ng_constructor_t ng_bridge_constructor;
 122 static ng_rcvmsg_t      ng_bridge_rcvmsg;
 123 static ng_shutdown_t    ng_bridge_shutdown;
 124 static ng_newhook_t     ng_bridge_newhook;
 125 static ng_rcvdata_t     ng_bridge_rcvdata;
 126 static ng_disconnect_t  ng_bridge_disconnect;
 127
 128 /* Other internal functions */
 129 static struct   ng_bridge_host *ng_bridge_get(priv_p priv, const u_char *addr);
 130 static int      ng_bridge_put(priv_p priv, const u_char *addr, link_p link);
 131 static void     ng_bridge_rehash(priv_p priv);
 132 static void     ng_bridge_remove_hosts(priv_p priv, link_p link);
 133 static void     ng_bridge_timeout(node_p node, hook_p hook, void *arg1, int arg2);
 134 static const    char *ng_bridge_nodename(node_p node);
 135
 136 /* Ethernet broadcast */
 137 static const u_char ng_bridge_bcast_addr[ETHER_ADDR_LEN] =
 138     { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
 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_struct_field ng_bridge_config_type_fields[]
 196         = NG_BRIDGE_CONFIG_TYPE_INFO;
 197 static const struct ng_parse_type ng_bridge_config_type = {
 198         &ng_parse_struct_type,
 199         &ng_bridge_config_type_fields
 200 };
 201
 202 /* Parse type for struct ng_bridge_link_stat */
 203 static const struct ng_parse_struct_field ng_bridge_stats_type_fields[]
 204         = NG_BRIDGE_STATS_TYPE_INFO;
 205 static const struct ng_parse_type ng_bridge_stats_type = {
 206         &ng_parse_struct_type,
 207         &ng_bridge_stats_type_fields
 208 };
 209
 210 /* List of commands and how to convert arguments to/from ASCII */
 211 static const struct ng_cmdlist ng_bridge_cmdlist[] = {
 212         {
 213           NGM_BRIDGE_COOKIE,
 214           NGM_BRIDGE_SET_CONFIG,
 215           "setconfig",
 216           &ng_bridge_config_type,
 217           NULL
 218         },
 219         {
 220           NGM_BRIDGE_COOKIE,
 221           NGM_BRIDGE_GET_CONFIG,
 222           "getconfig",
 223           NULL,
 224           &ng_bridge_config_type
 225         },
 226         {
 227           NGM_BRIDGE_COOKIE,
 228           NGM_BRIDGE_RESET,
 229           "reset",
 230           NULL,
 231           NULL
 232         },
 233         {
 234           NGM_BRIDGE_COOKIE,
 235           NGM_BRIDGE_GET_STATS,
 236           "getstats",
 237           &ng_parse_uint32_type,
 238           &ng_bridge_stats_type
 239         },
 240         {
 241           NGM_BRIDGE_COOKIE,
 242           NGM_BRIDGE_CLR_STATS,
 243           "clrstats",
 244           &ng_parse_uint32_type,
 245           NULL
 246         },
 247         {
 248           NGM_BRIDGE_COOKIE,
 249           NGM_BRIDGE_GETCLR_STATS,
 250           "getclrstats",
 251           &ng_parse_uint32_type,
 252           &ng_bridge_stats_type
 253         },
 254         {
 255           NGM_BRIDGE_COOKIE,
 256           NGM_BRIDGE_GET_TABLE,
 257           "gettable",
 258           NULL,
 259           &ng_bridge_host_ary_type
 260         },
 261         {
 262           NGM_BRIDGE_COOKIE,
 263           NGM_BRIDGE_SET_PERSISTENT,
 264           "setpersistent",
 265           NULL,
 266           NULL
 267         },
 268         { 0 }
 269 };
 270
 271 /* Node type descriptor */
 272 static struct ng_type ng_bridge_typestruct = {
 273         .version =      NG_ABI_VERSION,
 274         .name =         NG_BRIDGE_NODE_TYPE,
 275         .constructor =  ng_bridge_constructor,
 276         .rcvmsg =       ng_bridge_rcvmsg,
 277         .shutdown =     ng_bridge_shutdown,
 278         .newhook =      ng_bridge_newhook,
 279         .rcvdata =      ng_bridge_rcvdata,
 280         .disconnect =   ng_bridge_disconnect,
 281         .cmdlist =      ng_bridge_cmdlist,
 282 };
 283 NETGRAPH_INIT(bridge, &ng_bridge_typestruct);
 284
 285 /******************************************************************
 286                     NETGRAPH NODE METHODS
 287 ******************************************************************/
 288
 289 /*
 290  * Node constructor
 291  */
 292 static int
 293 ng_bridge_constructor(node_p node)
 294 {
 295         priv_p priv;
 296
 297         /* Allocate and initialize private info */
 298         priv = malloc(sizeof(*priv), M_NETGRAPH_BRIDGE, M_WAITOK | M_ZERO);
 299         ng_callout_init(&priv->timer);
 300
 301         /* Allocate and initialize hash table, etc. */
 302         priv->tab = malloc(MIN_BUCKETS * sizeof(*priv->tab),
 303             M_NETGRAPH_BRIDGE, M_WAITOK | M_ZERO);
 304         priv->numBuckets = MIN_BUCKETS;
 305         priv->hashMask = MIN_BUCKETS - 1;
 306         priv->conf.debugLevel = 1;
 307         priv->conf.loopTimeout = DEFAULT_LOOP_TIMEOUT;
 308         priv->conf.maxStaleness = DEFAULT_MAX_STALENESS;
 309         priv->conf.minStableAge = DEFAULT_MIN_STABLE_AGE;
 310
 311         /*
 312          * This node has all kinds of stuff that could be screwed by SMP.
 313          * Until it gets it's own internal protection, we go through in
 314          * single file. This could hurt a machine bridging between two
 315          * GB ethernets so it should be fixed.
 316          * When it's fixed the process SHOULD NOT SLEEP, spinlocks please!
 317          * (and atomic ops )
 318          */
 319         NG_NODE_FORCE_WRITER(node);
 320         NG_NODE_SET_PRIVATE(node, priv);
 321         priv->node = node;
 322
 323         /* Start timer; timer is always running while node is alive */
 324         ng_callout(&priv->timer, node, NULL, hz, ng_bridge_timeout, NULL, 0);
 325
 326         /* Done */
 327         return (0);
 328 }
 329
 330 /*
 331  * Method for attaching a new hook
 332  */
 333 static  int
 334 ng_bridge_newhook(node_p node, hook_p hook, const char *name)
 335 {
 336         const priv_p priv = NG_NODE_PRIVATE(node);
 337
 338         /* Check for a link hook */
 339         if (strlen(name) > strlen(NG_BRIDGE_HOOK_LINK_PREFIX)) {
 340                 char linkName[NG_HOOKSIZ];
 341                 u_int32_t linkNum;
 342                 link_p link;
 343
 344                 /* primitive parsing */
 345                 linkNum = strtoul(name + strlen(NG_BRIDGE_HOOK_LINK_PREFIX),
 346                                   NULL, 10);
 347                 /* validation by comparing against the reconstucted name  */
 348                 snprintf(linkName, sizeof(linkName),
 349                          "%s%u", NG_BRIDGE_HOOK_LINK_PREFIX,
 350                          linkNum);
 351                 if (strcmp(linkName, name) != 0)
 352                         return (EINVAL);
 353
 354                 if(NG_PEER_NODE(hook) == node)
 355                         return (ELOOP);
 356
 357                 link = malloc(sizeof(*link), M_NETGRAPH_BRIDGE,
 358                               M_WAITOK|M_ZERO);
 359                 if (link == NULL)
 360                         return (ENOMEM);
 361                 link->hook = hook;
 362                 NG_HOOK_SET_PRIVATE(hook, link);
 363                 priv->numLinks++;
 364                 return (0);
 365         }
 366
 367         /* Unknown hook name */
 368         return (EINVAL);
 369 }
 370
 371 /*
 372  * Receive a control message
 373  */
 374 static int
 375 ng_bridge_reset_link(hook_p hook, void *arg __unused)
 376 {
 377         link_p priv = NG_HOOK_PRIVATE(hook);
 378
 379         priv->loopCount = 0;
 380         bzero(&priv->stats, sizeof(priv->stats));
 381
 382         return (1);
 383 }
 384
 385
 386 static int
 387 ng_bridge_rcvmsg(node_p node, item_p item, hook_p lasthook)
 388 {
 389         const priv_p priv = NG_NODE_PRIVATE(node);
 390         struct ng_mesg *resp = NULL;
 391         int error = 0;
 392         struct ng_mesg *msg;
 393
 394         NGI_GET_MSG(item, msg);
 395         switch (msg->header.typecookie) {
 396         case NGM_BRIDGE_COOKIE:
 397                 switch (msg->header.cmd) {
 398                 case NGM_BRIDGE_GET_CONFIG:
 399                     {
 400                         struct ng_bridge_config *conf;
 401
 402                         NG_MKRESPONSE(resp, msg,
 403                             sizeof(struct ng_bridge_config), M_NOWAIT);
 404                         if (resp == NULL) {
 405                                 error = ENOMEM;
 406                                 break;
 407                         }
 408                         conf = (struct ng_bridge_config *)resp->data;
 409                         *conf = priv->conf;     /* no sanity checking needed */
 410                         break;
 411                     }
 412                 case NGM_BRIDGE_SET_CONFIG:
 413                     {
 414                         struct ng_bridge_config *conf;
 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                         break;
 424                     }
 425                 case NGM_BRIDGE_RESET:
 426                     {
 427                         hook_p rethook;
 428
 429                         /* Flush all entries in the hash table */
 430                         ng_bridge_remove_hosts(priv, NULL);
 431
 432                         /* Reset all loop detection counters and stats */
 433                         NG_NODE_FOREACH_HOOK(node, ng_bridge_reset_link, NULL,
 434                             rethook);
 435                         break;
 436                     }
 437                 case NGM_BRIDGE_GET_STATS:
 438                 case NGM_BRIDGE_CLR_STATS:
 439                 case NGM_BRIDGE_GETCLR_STATS:
 440                     {
 441                         hook_p hook;
 442                         link_p link;
 443                         char linkName[NG_HOOKSIZ];
 444
 445                         /* Get link number */
 446                         if (msg->header.arglen != sizeof(u_int32_t)) {
 447                                 error = EINVAL;
 448                                 break;
 449                         }
 450                         snprintf(linkName, sizeof(linkName),
 451                                  "%s%u", NG_BRIDGE_HOOK_LINK_PREFIX,
 452                                  *((u_int32_t *)msg->data));
 453
 454                         if ((hook = ng_findhook(node, linkName)) == NULL) {
 455                                 error = ENOTCONN;
 456                                 break;
 457                         }
 458                         link = NG_HOOK_PRIVATE(hook);
 459
 460                         /* Get/clear stats */
 461                         if (msg->header.cmd != NGM_BRIDGE_CLR_STATS) {
 462                                 NG_MKRESPONSE(resp, msg,
 463                                     sizeof(link->stats), M_NOWAIT);
 464                                 if (resp == NULL) {
 465                                         error = ENOMEM;
 466                                         break;
 467                                 }
 468                                 bcopy(&link->stats,
 469                                     resp->data, sizeof(link->stats));
 470                         }
 471                         if (msg->header.cmd != NGM_BRIDGE_GET_STATS)
 472                                 bzero(&link->stats, sizeof(link->stats));
 473                         break;
 474                     }
 475                 case NGM_BRIDGE_GET_TABLE:
 476                     {
 477                         struct ng_bridge_host_ary *ary;
 478                         struct ng_bridge_hent *hent;
 479                         int i = 0, bucket;
 480
 481                         NG_MKRESPONSE(resp, msg, sizeof(*ary)
 482                             + (priv->numHosts * sizeof(*ary->hosts)), M_NOWAIT);
 483                         if (resp == NULL) {
 484                                 error = ENOMEM;
 485                                 break;
 486                         }
 487                         ary = (struct ng_bridge_host_ary *)resp->data;
 488                         ary->numHosts = priv->numHosts;
 489                         for (bucket = 0; bucket < priv->numBuckets; bucket++) {
 490                                 SLIST_FOREACH(hent, &priv->tab[bucket], next) {
 491                                         memcpy(ary->hosts[i].addr,
 492                                                hent->host.addr,
 493                                                sizeof(ary->hosts[i].addr));
 494                                         ary->hosts[i].age       = hent->host.age;
 495                                         ary->hosts[i].staleness = hent->host.staleness;
 496                                         strncpy(ary->hosts[i].hook,
 497                                                 NG_HOOK_NAME(hent->host.link->hook),
 498                                                 sizeof(ary->hosts[i].hook));
 499                                         i++;
 500                                 }
 501                         }
 502                         break;
 503                     }
 504                 case NGM_BRIDGE_SET_PERSISTENT:
 505                     {
 506                         priv->persistent = 1;
 507                         break;
 508                     }
 509                 default:
 510                         error = EINVAL;
 511                         break;
 512                 }
 513                 break;
 514         default:
 515                 error = EINVAL;
 516                 break;
 517         }
 518
 519         /* Done */
 520         NG_RESPOND_MSG(error, node, item, resp);
 521         NG_FREE_MSG(msg);
 522         return (error);
 523 }
 524
 525 /*
 526  * Receive data on a hook
 527  */
 528 struct ng_bridge_send_ctx {
 529         link_p foundFirst, incoming;
 530         struct mbuf * m;
 531         int manycast, error;
 532 };
 533
 534 static int
 535 ng_bridge_send_ctx(hook_p dst, void *arg)
 536 {
 537         struct ng_bridge_send_ctx *ctx = arg;
 538         link_p destLink = NG_HOOK_PRIVATE(dst);
 539         struct mbuf *m2 = NULL;
 540         int error = 0;
 541
 542         /* Skip incoming link */
 543         if (destLink == ctx->incoming) {
 544                 return (1);
 545         }
 546
 547         if (ctx->foundFirst == NULL) {
 548                 /*
 549                  * This is the first usable link we have found.
 550                  * Reserve it for the originals.
 551                  * If we never find another we save a copy.
 552                  */
 553                 ctx->foundFirst = destLink;
 554                 return (1);
 555         }
 556
 557         /*
 558          * It's usable link but not the reserved (first) one.
 559          * Copy mbuf info for sending.
 560          */
 561         m2 = m_dup(ctx->m, M_NOWAIT);   /* XXX m_copypacket() */
 562         if (m2 == NULL) {
 563                 ctx->incoming->stats.memoryFailures++;
 564                 ctx->error = ENOBUFS;
 565                 return (0);            /* abort loop */
 566         }
 567
 568
 569         /* Update stats */
 570         destLink->stats.xmitPackets++;
 571         destLink->stats.xmitOctets += m2->m_pkthdr.len;
 572         switch (ctx->manycast) {
 573          default:                                       /* unknown unicast */
 574                 break;
 575          case 1:                                        /* multicast */
 576                 destLink->stats.xmitMulticasts++;
 577                 break;
 578          case 2:                                        /* broadcast */
 579                 destLink->stats.xmitBroadcasts++;
 580                 break;
 581         }
 582
 583         /* Send packet */
 584         NG_SEND_DATA_ONLY(error, destLink->hook, m2);
 585         if(error)
 586           ctx->error = error;
 587         return (1);
 588 }
 589
 590 static int
 591 ng_bridge_rcvdata(hook_p hook, item_p item)
 592 {
 593         const node_p node = NG_HOOK_NODE(hook);
 594         const priv_p priv = NG_NODE_PRIVATE(node);
 595         struct ng_bridge_host *host;
 596         struct ether_header *eh;
 597         struct ng_bridge_send_ctx ctx = { 0 };
 598         hook_p ret;
 599
 600         NGI_GET_M(item, ctx.m);
 601
 602         ctx.incoming = NG_HOOK_PRIVATE(hook);
 603         /* Sanity check packet and pull up header */
 604         if (ctx.m->m_pkthdr.len < ETHER_HDR_LEN) {
 605                 ctx.incoming->stats.recvRunts++;
 606                 NG_FREE_ITEM(item);
 607                 NG_FREE_M(ctx.m);
 608                 return (EINVAL);
 609         }
 610         if (ctx.m->m_len < ETHER_HDR_LEN && !(ctx.m = m_pullup(ctx.m, ETHER_HDR_LEN))) {
 611                 ctx.incoming->stats.memoryFailures++;
 612                 NG_FREE_ITEM(item);
 613                 return (ENOBUFS);
 614         }
 615         eh = mtod(ctx.m, struct ether_header *);
 616         if ((eh->ether_shost[0] & 1) != 0) {
 617                 ctx.incoming->stats.recvInvalid++;
 618                 NG_FREE_ITEM(item);
 619                 NG_FREE_M(ctx.m);
 620                 return (EINVAL);
 621         }
 622
 623         /* Is link disabled due to a loopback condition? */
 624         if (ctx.incoming->loopCount != 0) {
 625                 ctx.incoming->stats.loopDrops++;
 626                 NG_FREE_ITEM(item);
 627                 NG_FREE_M(ctx.m);
 628                 return (ELOOP);         /* XXX is this an appropriate error? */
 629         }
 630
 631         /* Update stats */
 632         ctx.incoming->stats.recvPackets++;
 633         ctx.incoming->stats.recvOctets += ctx.m->m_pkthdr.len;
 634         if ((ctx.manycast = (eh->ether_dhost[0] & 1)) != 0) {
 635                 if (ETHER_EQUAL(eh->ether_dhost, ng_bridge_bcast_addr)) {
 636                         ctx.incoming->stats.recvBroadcasts++;
 637                         ctx.manycast = 2;
 638                 } else
 639                         ctx.incoming->stats.recvMulticasts++;
 640         }
 641
 642         /* Look up packet's source Ethernet address in hashtable */
 643         if ((host = ng_bridge_get(priv, eh->ether_shost)) != NULL) {
 644
 645                 /* Update time since last heard from this host */
 646                 host->staleness = 0;
 647
 648                 /* Did host jump to a different link? */
 649                 if (host->link != ctx.incoming) {
 650
 651                         /*
 652                          * If the host's old link was recently established
 653                          * on the old link and it's already jumped to a new
 654                          * link, declare a loopback condition.
 655                          */
 656                         if (host->age < priv->conf.minStableAge) {
 657
 658                                 /* Log the problem */
 659                                 if (priv->conf.debugLevel >= 2) {
 660                                         struct ifnet *ifp = ctx.m->m_pkthdr.rcvif;
 661                                         char suffix[32];
 662
 663                                         if (ifp != NULL)
 664                                                 snprintf(suffix, sizeof(suffix),
 665                                                     " (%s)", ifp->if_xname);
 666                                         else
 667                                                 *suffix = '\0';
 668                                         log(LOG_WARNING, "ng_bridge: %s:"
 669                                             " loopback detected on %s%s\n",
 670                                             ng_bridge_nodename(node),
 671                                             NG_HOOK_NAME(hook), suffix);
 672                                 }
 673
 674                                 /* Mark link as linka non grata */
 675                                 ctx.incoming->loopCount = priv->conf.loopTimeout;
 676                                 ctx.incoming->stats.loopDetects++;
 677
 678                                 /* Forget all hosts on this link */
 679                                 ng_bridge_remove_hosts(priv, ctx.incoming);
 680
 681                                 /* Drop packet */
 682                                 ctx.incoming->stats.loopDrops++;
 683                                 NG_FREE_ITEM(item);
 684                                 NG_FREE_M(ctx.m);
 685                                 return (ELOOP);         /* XXX appropriate? */
 686                         }
 687
 688                         /* Move host over to new link */
 689                         host->link = ctx.incoming;
 690                         host->age = 0;
 691                 }
 692         } else {
 693                 if (!ng_bridge_put(priv, eh->ether_shost, ctx.incoming)) {
 694                         ctx.incoming->stats.memoryFailures++;
 695                         NG_FREE_ITEM(item);
 696                         NG_FREE_M(ctx.m);
 697                         return (ENOMEM);
 698                 }
 699         }
 700
 701         /* Run packet through ipfw processing, if enabled */
 702 #if 0
 703         if (priv->conf.ipfw[linkNum] && V_fw_enable && V_ip_fw_chk_ptr != NULL) {
 704                 /* XXX not implemented yet */
 705         }
 706 #endif
 707
 708         /*
 709          * If unicast and destination host known, deliver to host's link,
 710          * unless it is the same link as the packet came in on.
 711          */
 712         if (!ctx.manycast) {
 713
 714                 /* Determine packet destination link */
 715                 if ((host = ng_bridge_get(priv, eh->ether_dhost)) != NULL) {
 716                         link_p destLink = host->link;
 717
 718                         /* If destination same as incoming link, do nothing */
 719                         if (destLink == ctx.incoming) {
 720                                 NG_FREE_ITEM(item);
 721                                 NG_FREE_M(ctx.m);
 722                                 return (0);
 723                         }
 724
 725                         /* Deliver packet out the destination link */
 726                         destLink->stats.xmitPackets++;
 727                         destLink->stats.xmitOctets += ctx.m->m_pkthdr.len;
 728                         NG_FWD_NEW_DATA(ctx.error, item, destLink->hook, ctx.m);
 729                         return (ctx.error);
 730                 }
 731
 732                 /* Destination host is not known */
 733                 ctx.incoming->stats.recvUnknown++;
 734         }
 735
 736         /* Distribute unknown, multicast, broadcast pkts to all other links */
 737         NG_NODE_FOREACH_HOOK(node, ng_bridge_send_ctx, &ctx, ret);
 738
 739         /* If we never saw a good link, leave. */
 740         if (ctx.foundFirst == NULL || ctx.error != 0) {
 741                 NG_FREE_ITEM(item);
 742                 NG_FREE_M(ctx.m);
 743                 return (ctx.error);
 744         }
 745
 746         /*
 747          * If we've sent all the others, send the original
 748          * on the first link we found.
 749          */
 750         NG_FWD_NEW_DATA(ctx.error, item, ctx.foundFirst->hook, ctx.m);
 751         return (ctx.error);
 752 }
 753
 754 /*
 755  * Shutdown node
 756  */
 757 static int
 758 ng_bridge_shutdown(node_p node)
 759 {
 760         const priv_p priv = NG_NODE_PRIVATE(node);
 761
 762         /*
 763          * Shut down everything including the timer.  Even if the
 764          * callout has already been dequeued and is about to be
 765          * run, ng_bridge_timeout() won't be fired as the node
 766          * is already marked NGF_INVALID, so we're safe to free
 767          * the node now.
 768          */
 769         KASSERT(priv->numLinks == 0 && priv->numHosts == 0,
 770             ("%s: numLinks=%d numHosts=%d",
 771             __func__, priv->numLinks, priv->numHosts));
 772         ng_uncallout(&priv->timer, node);
 773         NG_NODE_SET_PRIVATE(node, NULL);
 774         NG_NODE_UNREF(node);
 775         free(priv->tab, M_NETGRAPH_BRIDGE);
 776         free(priv, M_NETGRAPH_BRIDGE);
 777         return (0);
 778 }
 779
 780 /*
 781  * Hook disconnection.
 782  */
 783 static int
 784 ng_bridge_disconnect(hook_p hook)
 785 {
 786         const priv_p priv = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
 787         link_p link = NG_HOOK_PRIVATE(hook);
 788
 789         /* Remove all hosts associated with this link */
 790         ng_bridge_remove_hosts(priv, link);
 791
 792         /* Free associated link information */
 793         free(link, M_NETGRAPH_BRIDGE);
 794         priv->numLinks--;
 795
 796         /* If no more hooks, go away */
 797         if ((NG_NODE_NUMHOOKS(NG_HOOK_NODE(hook)) == 0)
 798             && (NG_NODE_IS_VALID(NG_HOOK_NODE(hook)))
 799             && !priv->persistent) {
 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, link_p link)
 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         hent = malloc(sizeof(*hent), M_NETGRAPH_BRIDGE, M_NOWAIT);
 853         if (hent == NULL)
 854                 return (0);
 855         bcopy(addr, hent->host.addr, ETHER_ADDR_LEN);
 856         hent->host.link = link;
 857         hent->host.staleness = 0;
 858         hent->host.age = 0;
 859
 860         /* Add new element to hash bucket */
 861         SLIST_INSERT_HEAD(&priv->tab[bucket], hent, next);
 862         priv->numHosts++;
 863
 864         /* Resize table if necessary */
 865         ng_bridge_rehash(priv);
 866         return (1);
 867 }
 868
 869 /*
 870  * Resize the hash table. We try to maintain the number of buckets
 871  * such that the load factor is in the range 0.25 to 1.0.
 872  *
 873  * If we can't get the new memory then we silently fail. This is OK
 874  * because things will still work and we'll try again soon anyway.
 875  */
 876 static void
 877 ng_bridge_rehash(priv_p priv)
 878 {
 879         struct ng_bridge_bucket *newTab;
 880         int oldBucket, newBucket;
 881         int newNumBuckets;
 882         u_int newMask;
 883
 884         /* Is table too full or too empty? */
 885         if (priv->numHosts > priv->numBuckets
 886             && (priv->numBuckets << 1) <= MAX_BUCKETS)
 887                 newNumBuckets = priv->numBuckets << 1;
 888         else if (priv->numHosts < (priv->numBuckets >> 2)
 889             && (priv->numBuckets >> 2) >= MIN_BUCKETS)
 890                 newNumBuckets = priv->numBuckets >> 2;
 891         else
 892                 return;
 893         newMask = newNumBuckets - 1;
 894
 895         /* Allocate and initialize new table */
 896         newTab = malloc(newNumBuckets * sizeof(*newTab),
 897             M_NETGRAPH_BRIDGE, M_NOWAIT | M_ZERO);
 898         if (newTab == NULL)
 899                 return;
 900
 901         /* Move all entries from old table to new table */
 902         for (oldBucket = 0; oldBucket < priv->numBuckets; oldBucket++) {
 903                 struct ng_bridge_bucket *const oldList = &priv->tab[oldBucket];
 904
 905                 while (!SLIST_EMPTY(oldList)) {
 906                         struct ng_bridge_hent *const hent
 907                             = SLIST_FIRST(oldList);
 908
 909                         SLIST_REMOVE_HEAD(oldList, next);
 910                         newBucket = HASH(hent->host.addr, newMask);
 911                         SLIST_INSERT_HEAD(&newTab[newBucket], hent, next);
 912                 }
 913         }
 914
 915         /* Replace old table with new one */
 916         if (priv->conf.debugLevel >= 3) {
 917                 log(LOG_INFO, "ng_bridge: %s: table size %d -> %d\n",
 918                     ng_bridge_nodename(priv->node),
 919                     priv->numBuckets, newNumBuckets);
 920         }
 921         free(priv->tab, M_NETGRAPH_BRIDGE);
 922         priv->numBuckets = newNumBuckets;
 923         priv->hashMask = newMask;
 924         priv->tab = newTab;
 925         return;
 926 }
 927
 928 /******************************************************************
 929                     MISC FUNCTIONS
 930 ******************************************************************/
 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, link_p link)
 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 (link == NULL || hent->host.link == link) {
 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 int
 965 ng_bridge_unmute(hook_p hook, void *arg)
 966 {
 967         link_p link = NG_HOOK_PRIVATE(hook);
 968         node_p node = NG_HOOK_NODE(hook);
 969         priv_p priv = NG_NODE_PRIVATE(node);
 970         int *counter = arg;
 971
 972         if (link->loopCount != 0) {
 973                 link->loopCount--;
 974                 if (link->loopCount == 0 && priv->conf.debugLevel >= 2) {
 975                         log(LOG_INFO, "ng_bridge: %s:"
 976                             " restoring looped back %s\n",
 977                             ng_bridge_nodename(node), NG_HOOK_NAME(hook));
 978                 }
 979         }
 980         (*counter)++;
 981         return (1);
 982 }
 983
 984 static void
 985 ng_bridge_timeout(node_p node, hook_p hook, void *arg1, int arg2)
 986 {
 987         const priv_p priv = NG_NODE_PRIVATE(node);
 988         int bucket;
 989         int counter = 0;
 990         hook_p ret;
 991
 992         /* Update host time counters and remove stale entries */
 993         for (bucket = 0; bucket < priv->numBuckets; bucket++) {
 994                 struct ng_bridge_hent **hptr = &SLIST_FIRST(&priv->tab[bucket]);
 995
 996                 while (*hptr != NULL) {
 997                         struct ng_bridge_hent *const hent = *hptr;
 998
 999                         /* Remove hosts we haven't heard from in a while */
1000                         if (++hent->host.staleness >= priv->conf.maxStaleness) {
1001                                 *hptr = SLIST_NEXT(hent, next);
1002                                 free(hent, M_NETGRAPH_BRIDGE);
1003                                 priv->numHosts--;
1004                         } else {
1005                                 if (hent->host.age < 0xffff)
1006                                         hent->host.age++;
1007                                 hptr = &SLIST_NEXT(hent, next);
1008                                 counter++;
1009                         }
1010                 }
1011         }
1012         KASSERT(priv->numHosts == counter,
1013             ("%s: hosts: %d != %d", __func__, priv->numHosts, counter));
1014
1015         /* Decrease table size if necessary */
1016         ng_bridge_rehash(priv);
1017
1018         /* Decrease loop counter on muted looped back links */
1019         counter = 0;
1020         NG_NODE_FOREACH_HOOK(node, ng_bridge_unmute, &counter, ret);
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_HAS_NAME(node))
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