sys/netgraph/ng_bridge.c

   1 /*
   2  * ng_bridge.c
   3  */
   4
   5 /*-
   6  * Copyright (c) 2000 Whistle Communications, Inc.
   7  * All rights reserved.
   8  *
   9  * Subject to the following obligations and disclaimer of warranty, use and
  10  * redistribution of this software, in source or object code forms, with or
  11  * without modifications are expressly permitted by Whistle Communications;
  12  * provided, however, that:
  13  * 1. Any and all reproductions of the source or object code must include the
  14  *    copyright notice above and the following disclaimer of warranties; and
  15  * 2. No rights are granted, in any manner or form, to use Whistle
  16  *    Communications, Inc. trademarks, including the mark "WHISTLE
  17  *    COMMUNICATIONS" on advertising, endorsements, or otherwise except as
  18  *    such appears in the above copyright notice or in the software.
  19  *
  20  * THIS SOFTWARE IS BEING PROVIDED BY WHISTLE COMMUNICATIONS "AS IS", AND
  21  * TO THE MAXIMUM EXTENT PERMITTED BY LAW, WHISTLE COMMUNICATIONS MAKES NO
  22  * REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED, REGARDING THIS SOFTWARE,
  23  * INCLUDING WITHOUT LIMITATION, ANY AND ALL IMPLIED WARRANTIES OF
  24  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT.
  25  * WHISTLE COMMUNICATIONS DOES NOT WARRANT, GUARANTEE, OR MAKE ANY
  26  * REPRESENTATIONS REGARDING THE USE OF, OR THE RESULTS OF THE USE OF THIS
  27  * SOFTWARE IN TERMS OF ITS CORRECTNESS, ACCURACY, RELIABILITY OR OTHERWISE.
  28  * IN NO EVENT SHALL WHISTLE COMMUNICATIONS BE LIABLE FOR ANY DAMAGES
  29  * RESULTING FROM OR ARISING OUT OF ANY USE OF THIS SOFTWARE, INCLUDING
  30  * WITHOUT LIMITATION, ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
  31  * PUNITIVE, OR CONSEQUENTIAL DAMAGES, PROCUREMENT OF SUBSTITUTE GOODS OR
  32  * SERVICES, LOSS OF USE, DATA OR PROFITS, HOWEVER CAUSED AND UNDER ANY
  33  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  34  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  35  * THIS SOFTWARE, EVEN IF WHISTLE COMMUNICATIONS IS ADVISED OF THE POSSIBILITY
  36  * OF SUCH DAMAGE.
  37  *
  38  * Author: Archie Cobbs <archie@freebsd.org>
  39  *
  40  * $FreeBSD$
  41  */
  42
  43 /*
  44  * ng_bridge(4) netgraph node type
  45  *
  46  * The node performs standard intelligent Ethernet bridging over
  47  * each of its connected hooks, or links.  A simple loop detection
  48  * algorithm is included which disables a link for priv->conf.loopTimeout
  49  * seconds when a host is seen to have jumped from one link to
  50  * another within priv->conf.minStableAge seconds.
  51  *
  52  * We keep a hashtable that maps Ethernet addresses to host info,
  53  * which is contained in struct ng_bridge_host's. These structures
  54  * tell us on which link the host may be found. A host's entry will
  55  * expire after priv->conf.maxStaleness seconds.
  56  *
  57  * This node is optimzed for stable networks, where machines jump
  58  * from one port to the other only rarely.
  59  */
  60
  61 #include <sys/param.h>
  62 #include <sys/systm.h>
  63 #include <sys/kernel.h>
  64 #include <sys/lock.h>
  65 #include <sys/malloc.h>
  66 #include <sys/mbuf.h>
  67 #include <sys/errno.h>
  68 #include <sys/rwlock.h>
  69 #include <sys/syslog.h>
  70 #include <sys/socket.h>
  71 #include <sys/ctype.h>
  72
  73 #include <net/if.h>
  74 #include <net/ethernet.h>
  75 #include <net/vnet.h>
  76
  77 #include <netinet/in.h>
  78 #if 0   /* not used yet */
  79 #include <netinet/ip_fw.h>
  80 #endif
  81 #include <netgraph/ng_message.h>
  82 #include <netgraph/netgraph.h>
  83 #include <netgraph/ng_parse.h>
  84 #include <netgraph/ng_bridge.h>
  85
  86 #ifdef NG_SEPARATE_MALLOC
  87 MALLOC_DEFINE(M_NETGRAPH_BRIDGE, "netgraph_bridge", "netgraph bridge node");
  88 #else
  89 #define M_NETGRAPH_BRIDGE M_NETGRAPH
  90 #endif
  91
  92 /* Per-link private data */
  93 struct ng_bridge_link {
  94         hook_p                          hook;           /* netgraph hook */
  95         u_int16_t                       loopCount;      /* loop ignore timer */
  96         struct ng_bridge_link_stats     stats;          /* link stats */
  97 };
  98
  99 /* Per-node private data */
 100 struct ng_bridge_private {
 101         struct ng_bridge_bucket *tab;           /* hash table bucket array */
 102         struct ng_bridge_link   *links[NG_BRIDGE_MAX_LINKS];
 103         struct ng_bridge_config conf;           /* node configuration */
 104         node_p                  node;           /* netgraph node */
 105         u_int                   numHosts;       /* num entries in table */
 106         u_int                   numBuckets;     /* num buckets in table */
 107         u_int                   hashMask;       /* numBuckets - 1 */
 108         int                     numLinks;       /* num connected links */
 109         int                     persistent;     /* can exist w/o hooks */
 110         struct callout          timer;          /* one second periodic timer */
 111 };
 112 typedef struct ng_bridge_private *priv_p;
 113
 114 /* Information about a host, stored in a hash table entry */
 115 struct ng_bridge_hent {
 116         struct ng_bridge_host           host;   /* actual host info */
 117         SLIST_ENTRY(ng_bridge_hent)     next;   /* next entry in bucket */
 118 };
 119
 120 /* Hash table bucket declaration */
 121 SLIST_HEAD(ng_bridge_bucket, ng_bridge_hent);
 122
 123 /* Netgraph node methods */
 124 static ng_constructor_t ng_bridge_constructor;
 125 static ng_rcvmsg_t      ng_bridge_rcvmsg;
 126 static ng_shutdown_t    ng_bridge_shutdown;
 127 static ng_newhook_t     ng_bridge_newhook;
 128 static ng_rcvdata_t     ng_bridge_rcvdata;
 129 static ng_disconnect_t  ng_bridge_disconnect;
 130
 131 /* Other internal functions */
 132 static struct   ng_bridge_host *ng_bridge_get(priv_p priv, const u_char *addr);
 133 static int      ng_bridge_put(priv_p priv, const u_char *addr, int linkNum);
 134 static void     ng_bridge_rehash(priv_p priv);
 135 static void     ng_bridge_remove_hosts(priv_p priv, int linkNum);
 136 static void     ng_bridge_timeout(node_p node, hook_p hook, void *arg1, int arg2);
 137 static const    char *ng_bridge_nodename(node_p node);
 138
 139 /* Ethernet broadcast */
 140 static const u_char ng_bridge_bcast_addr[ETHER_ADDR_LEN] =
 141     { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
 142
 143 /* Store each hook's link number in the private field */
 144 #define LINK_NUM(hook)          (*(u_int16_t *)(&(hook)->private))
 145
 146 /* Compare Ethernet addresses using 32 and 16 bit words instead of bytewise */
 147 #define ETHER_EQUAL(a,b)        (((const u_int32_t *)(a))[0] \
 148                                         == ((const u_int32_t *)(b))[0] \
 149                                     && ((const u_int16_t *)(a))[2] \
 150                                         == ((const u_int16_t *)(b))[2])
 151
 152 /* Minimum and maximum number of hash buckets. Must be a power of two. */
 153 #define MIN_BUCKETS             (1 << 5)        /* 32 */
 154 #define MAX_BUCKETS             (1 << 14)       /* 16384 */
 155
 156 /* Configuration default values */
 157 #define DEFAULT_LOOP_TIMEOUT    60
 158 #define DEFAULT_MAX_STALENESS   (15 * 60)       /* same as ARP timeout */
 159 #define DEFAULT_MIN_STABLE_AGE  1
 160
 161 /******************************************************************
 162                     NETGRAPH PARSE TYPES
 163 ******************************************************************/
 164
 165 /*
 166  * How to determine the length of the table returned by NGM_BRIDGE_GET_TABLE
 167  */
 168 static int
 169 ng_bridge_getTableLength(const struct ng_parse_type *type,
 170         const u_char *start, const u_char *buf)
 171 {
 172         const struct ng_bridge_host_ary *const hary
 173             = (const struct ng_bridge_host_ary *)(buf - sizeof(u_int32_t));
 174
 175         return hary->numHosts;
 176 }
 177
 178 /* Parse type for struct ng_bridge_host_ary */
 179 static const struct ng_parse_struct_field ng_bridge_host_type_fields[]
 180         = NG_BRIDGE_HOST_TYPE_INFO(&ng_parse_enaddr_type);
 181 static const struct ng_parse_type ng_bridge_host_type = {
 182         &ng_parse_struct_type,
 183         &ng_bridge_host_type_fields
 184 };
 185 static const struct ng_parse_array_info ng_bridge_hary_type_info = {
 186         &ng_bridge_host_type,
 187         ng_bridge_getTableLength
 188 };
 189 static const struct ng_parse_type ng_bridge_hary_type = {
 190         &ng_parse_array_type,
 191         &ng_bridge_hary_type_info
 192 };
 193 static const struct ng_parse_struct_field ng_bridge_host_ary_type_fields[]
 194         = NG_BRIDGE_HOST_ARY_TYPE_INFO(&ng_bridge_hary_type);
 195 static const struct ng_parse_type ng_bridge_host_ary_type = {
 196         &ng_parse_struct_type,
 197         &ng_bridge_host_ary_type_fields
 198 };
 199
 200 /* Parse type for struct ng_bridge_config */
 201 static const struct ng_parse_fixedarray_info ng_bridge_ipfwary_type_info = {
 202         &ng_parse_uint8_type,
 203         NG_BRIDGE_MAX_LINKS
 204 };
 205 static const struct ng_parse_type ng_bridge_ipfwary_type = {
 206         &ng_parse_fixedarray_type,
 207         &ng_bridge_ipfwary_type_info
 208 };
 209 static const struct ng_parse_struct_field ng_bridge_config_type_fields[]
 210         = NG_BRIDGE_CONFIG_TYPE_INFO(&ng_bridge_ipfwary_type);
 211 static const struct ng_parse_type ng_bridge_config_type = {
 212         &ng_parse_struct_type,
 213         &ng_bridge_config_type_fields
 214 };
 215
 216 /* Parse type for struct ng_bridge_link_stat */
 217 static const struct ng_parse_struct_field ng_bridge_stats_type_fields[]
 218         = NG_BRIDGE_STATS_TYPE_INFO;
 219 static const struct ng_parse_type ng_bridge_stats_type = {
 220         &ng_parse_struct_type,
 221         &ng_bridge_stats_type_fields
 222 };
 223
 224 /* List of commands and how to convert arguments to/from ASCII */
 225 static const struct ng_cmdlist ng_bridge_cmdlist[] = {
 226         {
 227           NGM_BRIDGE_COOKIE,
 228           NGM_BRIDGE_SET_CONFIG,
 229           "setconfig",
 230           &ng_bridge_config_type,
 231           NULL
 232         },
 233         {
 234           NGM_BRIDGE_COOKIE,
 235           NGM_BRIDGE_GET_CONFIG,
 236           "getconfig",
 237           NULL,
 238           &ng_bridge_config_type
 239         },
 240         {
 241           NGM_BRIDGE_COOKIE,
 242           NGM_BRIDGE_RESET,
 243           "reset",
 244           NULL,
 245           NULL
 246         },
 247         {
 248           NGM_BRIDGE_COOKIE,
 249           NGM_BRIDGE_GET_STATS,
 250           "getstats",
 251           &ng_parse_uint32_type,
 252           &ng_bridge_stats_type
 253         },
 254         {
 255           NGM_BRIDGE_COOKIE,
 256           NGM_BRIDGE_CLR_STATS,
 257           "clrstats",
 258           &ng_parse_uint32_type,
 259           NULL
 260         },
 261         {
 262           NGM_BRIDGE_COOKIE,
 263           NGM_BRIDGE_GETCLR_STATS,
 264           "getclrstats",
 265           &ng_parse_uint32_type,
 266           &ng_bridge_stats_type
 267         },
 268         {
 269           NGM_BRIDGE_COOKIE,
 270           NGM_BRIDGE_GET_TABLE,
 271           "gettable",
 272           NULL,
 273           &ng_bridge_host_ary_type
 274         },
 275         {
 276           NGM_BRIDGE_COOKIE,
 277           NGM_BRIDGE_SET_PERSISTENT,
 278           "setpersistent",
 279           NULL,
 280           NULL
 281         },
 282         { 0 }
 283 };
 284
 285 /* Node type descriptor */
 286 static struct ng_type ng_bridge_typestruct = {
 287         .version =      NG_ABI_VERSION,
 288         .name =         NG_BRIDGE_NODE_TYPE,
 289         .constructor =  ng_bridge_constructor,
 290         .rcvmsg =       ng_bridge_rcvmsg,
 291         .shutdown =     ng_bridge_shutdown,
 292         .newhook =      ng_bridge_newhook,
 293         .rcvdata =      ng_bridge_rcvdata,
 294         .disconnect =   ng_bridge_disconnect,
 295         .cmdlist =      ng_bridge_cmdlist,
 296 };
 297 NETGRAPH_INIT(bridge, &ng_bridge_typestruct);
 298
 299 /******************************************************************
 300                     NETGRAPH NODE METHODS
 301 ******************************************************************/
 302
 303 /*
 304  * Node constructor
 305  */
 306 static int
 307 ng_bridge_constructor(node_p node)
 308 {
 309         priv_p priv;
 310
 311         /* Allocate and initialize private info */
 312         priv = malloc(sizeof(*priv), M_NETGRAPH_BRIDGE, M_WAITOK | M_ZERO);
 313         ng_callout_init(&priv->timer);
 314
 315         /* Allocate and initialize hash table, etc. */
 316         priv->tab = malloc(MIN_BUCKETS * sizeof(*priv->tab),
 317             M_NETGRAPH_BRIDGE, M_WAITOK | M_ZERO);
 318         priv->numBuckets = MIN_BUCKETS;
 319         priv->hashMask = MIN_BUCKETS - 1;
 320         priv->conf.debugLevel = 1;
 321         priv->conf.loopTimeout = DEFAULT_LOOP_TIMEOUT;
 322         priv->conf.maxStaleness = DEFAULT_MAX_STALENESS;
 323         priv->conf.minStableAge = DEFAULT_MIN_STABLE_AGE;
 324
 325         /*
 326          * This node has all kinds of stuff that could be screwed by SMP.
 327          * Until it gets it's own internal protection, we go through in
 328          * single file. This could hurt a machine bridging beteen two
 329          * GB ethernets so it should be fixed.
 330          * When it's fixed the process SHOULD NOT SLEEP, spinlocks please!
 331          * (and atomic ops )
 332          */
 333         NG_NODE_FORCE_WRITER(node);
 334         NG_NODE_SET_PRIVATE(node, priv);
 335         priv->node = node;
 336
 337         /* Start timer; timer is always running while node is alive */
 338         ng_callout(&priv->timer, node, NULL, hz, ng_bridge_timeout, NULL, 0);
 339
 340         /* Done */
 341         return (0);
 342 }
 343
 344 /*
 345  * Method for attaching a new hook
 346  */
 347 static  int
 348 ng_bridge_newhook(node_p node, hook_p hook, const char *name)
 349 {
 350         const priv_p priv = NG_NODE_PRIVATE(node);
 351
 352         /* Check for a link hook */
 353         if (strncmp(name, NG_BRIDGE_HOOK_LINK_PREFIX,
 354             strlen(NG_BRIDGE_HOOK_LINK_PREFIX)) == 0) {
 355                 const char *cp;
 356                 char *eptr;
 357                 u_long linkNum;
 358
 359                 cp = name + strlen(NG_BRIDGE_HOOK_LINK_PREFIX);
 360                 if (!isdigit(*cp) || (cp[0] == '0' && cp[1] != '\0'))
 361                         return (EINVAL);
 362                 linkNum = strtoul(cp, &eptr, 10);
 363                 if (*eptr != '\0' || linkNum >= NG_BRIDGE_MAX_LINKS)
 364                         return (EINVAL);
 365                 if (priv->links[linkNum] != NULL)
 366                         return (EISCONN);
 367                 priv->links[linkNum] = malloc(sizeof(*priv->links[linkNum]),
 368                     M_NETGRAPH_BRIDGE, M_NOWAIT|M_ZERO);
 369                 if (priv->links[linkNum] == NULL)
 370                         return (ENOMEM);
 371                 priv->links[linkNum]->hook = hook;
 372                 NG_HOOK_SET_PRIVATE(hook, (void *)linkNum);
 373                 priv->numLinks++;
 374                 return (0);
 375         }
 376
 377         /* Unknown hook name */
 378         return (EINVAL);
 379 }
 380
 381 /*
 382  * Receive a control message
 383  */
 384 static int
 385 ng_bridge_rcvmsg(node_p node, item_p item, hook_p lasthook)
 386 {
 387         const priv_p priv = NG_NODE_PRIVATE(node);
 388         struct ng_mesg *resp = NULL;
 389         int error = 0;
 390         struct ng_mesg *msg;
 391
 392         NGI_GET_MSG(item, msg);
 393         switch (msg->header.typecookie) {
 394         case NGM_BRIDGE_COOKIE:
 395                 switch (msg->header.cmd) {
 396                 case NGM_BRIDGE_GET_CONFIG:
 397                     {
 398                         struct ng_bridge_config *conf;
 399
 400                         NG_MKRESPONSE(resp, msg,
 401                             sizeof(struct ng_bridge_config), M_NOWAIT);
 402                         if (resp == NULL) {
 403                                 error = ENOMEM;
 404                                 break;
 405                         }
 406                         conf = (struct ng_bridge_config *)resp->data;
 407                         *conf = priv->conf;     /* no sanity checking needed */
 408                         break;
 409                     }
 410                 case NGM_BRIDGE_SET_CONFIG:
 411                     {
 412                         struct ng_bridge_config *conf;
 413                         int i;
 414
 415                         if (msg->header.arglen
 416                             != sizeof(struct ng_bridge_config)) {
 417                                 error = EINVAL;
 418                                 break;
 419                         }
 420                         conf = (struct ng_bridge_config *)msg->data;
 421                         priv->conf = *conf;
 422                         for (i = 0; i < NG_BRIDGE_MAX_LINKS; i++)
 423                                 priv->conf.ipfw[i] = !!priv->conf.ipfw[i];
 424                         break;
 425                     }
 426                 case NGM_BRIDGE_RESET:
 427                     {
 428                         int i;
 429
 430                         /* Flush all entries in the hash table */
 431                         ng_bridge_remove_hosts(priv, -1);
 432
 433                         /* Reset all loop detection counters and stats */
 434                         for (i = 0; i < NG_BRIDGE_MAX_LINKS; i++) {
 435                                 if (priv->links[i] == NULL)
 436                                         continue;
 437                                 priv->links[i]->loopCount = 0;
 438                                 bzero(&priv->links[i]->stats,
 439                                     sizeof(priv->links[i]->stats));
 440                         }
 441                         break;
 442                     }
 443                 case NGM_BRIDGE_GET_STATS:
 444                 case NGM_BRIDGE_CLR_STATS:
 445                 case NGM_BRIDGE_GETCLR_STATS:
 446                     {
 447                         struct ng_bridge_link *link;
 448                         int linkNum;
 449
 450                         /* Get link number */
 451                         if (msg->header.arglen != sizeof(u_int32_t)) {
 452                                 error = EINVAL;
 453                                 break;
 454                         }
 455                         linkNum = *((u_int32_t *)msg->data);
 456                         if (linkNum < 0 || linkNum >= NG_BRIDGE_MAX_LINKS) {
 457                                 error = EINVAL;
 458                                 break;
 459                         }
 460                         if ((link = priv->links[linkNum]) == NULL) {
 461                                 error = ENOTCONN;
 462                                 break;
 463                         }
 464
 465                         /* Get/clear stats */
 466                         if (msg->header.cmd != NGM_BRIDGE_CLR_STATS) {
 467                                 NG_MKRESPONSE(resp, msg,
 468                                     sizeof(link->stats), M_NOWAIT);
 469                                 if (resp == NULL) {
 470                                         error = ENOMEM;
 471                                         break;
 472                                 }
 473                                 bcopy(&link->stats,
 474                                     resp->data, sizeof(link->stats));
 475                         }
 476                         if (msg->header.cmd != NGM_BRIDGE_GET_STATS)
 477                                 bzero(&link->stats, sizeof(link->stats));
 478                         break;
 479                     }
 480                 case NGM_BRIDGE_GET_TABLE:
 481                     {
 482                         struct ng_bridge_host_ary *ary;
 483                         struct ng_bridge_hent *hent;
 484                         int i = 0, bucket;
 485
 486                         NG_MKRESPONSE(resp, msg, sizeof(*ary)
 487                             + (priv->numHosts * sizeof(*ary->hosts)), M_NOWAIT);
 488                         if (resp == NULL) {
 489                                 error = ENOMEM;
 490                                 break;
 491                         }
 492                         ary = (struct ng_bridge_host_ary *)resp->data;
 493                         ary->numHosts = priv->numHosts;
 494                         for (bucket = 0; bucket < priv->numBuckets; bucket++) {
 495                                 SLIST_FOREACH(hent, &priv->tab[bucket], next)
 496                                         ary->hosts[i++] = hent->host;
 497                         }
 498                         break;
 499                     }
 500                 case NGM_BRIDGE_SET_PERSISTENT:
 501                     {
 502                         priv->persistent = 1;
 503                         break;
 504                     }
 505                 default:
 506                         error = EINVAL;
 507                         break;
 508                 }
 509                 break;
 510         default:
 511                 error = EINVAL;
 512                 break;
 513         }
 514
 515         /* Done */
 516         NG_RESPOND_MSG(error, node, item, resp);
 517         NG_FREE_MSG(msg);
 518         return (error);
 519 }
 520
 521 /*
 522  * Receive data on a hook
 523  */
 524 static int
 525 ng_bridge_rcvdata(hook_p hook, item_p item)
 526 {
 527         const node_p node = NG_HOOK_NODE(hook);
 528         const priv_p priv = NG_NODE_PRIVATE(node);
 529         struct ng_bridge_host *host;
 530         struct ng_bridge_link *link;
 531         struct ether_header *eh;
 532         int error = 0, linkNum, linksSeen;
 533         int manycast;
 534         struct mbuf *m;
 535         struct ng_bridge_link *firstLink;
 536
 537         NGI_GET_M(item, m);
 538         /* Get link number */
 539         linkNum = (intptr_t)NG_HOOK_PRIVATE(hook);
 540         KASSERT(linkNum >= 0 && linkNum < NG_BRIDGE_MAX_LINKS,
 541             ("%s: linkNum=%u", __func__, linkNum));
 542         link = priv->links[linkNum];
 543         KASSERT(link != NULL, ("%s: link%d null", __func__, linkNum));
 544
 545         /* Sanity check packet and pull up header */
 546         if (m->m_pkthdr.len < ETHER_HDR_LEN) {
 547                 link->stats.recvRunts++;
 548                 NG_FREE_ITEM(item);
 549                 NG_FREE_M(m);
 550                 return (EINVAL);
 551         }
 552         if (m->m_len < ETHER_HDR_LEN && !(m = m_pullup(m, ETHER_HDR_LEN))) {
 553                 link->stats.memoryFailures++;
 554                 NG_FREE_ITEM(item);
 555                 return (ENOBUFS);
 556         }
 557         eh = mtod(m, struct ether_header *);
 558         if ((eh->ether_shost[0] & 1) != 0) {
 559                 link->stats.recvInvalid++;
 560                 NG_FREE_ITEM(item);
 561                 NG_FREE_M(m);
 562                 return (EINVAL);
 563         }
 564
 565         /* Is link disabled due to a loopback condition? */
 566         if (link->loopCount != 0) {
 567                 link->stats.loopDrops++;
 568                 NG_FREE_ITEM(item);
 569                 NG_FREE_M(m);
 570                 return (ELOOP);         /* XXX is this an appropriate error? */
 571         }
 572
 573         /* Update stats */
 574         link->stats.recvPackets++;
 575         link->stats.recvOctets += m->m_pkthdr.len;
 576         if ((manycast = (eh->ether_dhost[0] & 1)) != 0) {
 577                 if (ETHER_EQUAL(eh->ether_dhost, ng_bridge_bcast_addr)) {
 578                         link->stats.recvBroadcasts++;
 579                         manycast = 2;
 580                 } else
 581                         link->stats.recvMulticasts++;
 582         }
 583
 584         /* Look up packet's source Ethernet address in hashtable */
 585         if ((host = ng_bridge_get(priv, eh->ether_shost)) != NULL) {
 586
 587                 /* Update time since last heard from this host */
 588                 host->staleness = 0;
 589
 590                 /* Did host jump to a different link? */
 591                 if (host->linkNum != linkNum) {
 592
 593                         /*
 594                          * If the host's old link was recently established
 595                          * on the old link and it's already jumped to a new
 596                          * link, declare a loopback condition.
 597                          */
 598                         if (host->age < priv->conf.minStableAge) {
 599
 600                                 /* Log the problem */
 601                                 if (priv->conf.debugLevel >= 2) {
 602                                         struct ifnet *ifp = m->m_pkthdr.rcvif;
 603                                         char suffix[32];
 604
 605                                         if (ifp != NULL)
 606                                                 snprintf(suffix, sizeof(suffix),
 607                                                     " (%s)", ifp->if_xname);
 608                                         else
 609                                                 *suffix = '\0';
 610                                         log(LOG_WARNING, "ng_bridge: %s:"
 611                                             " loopback detected on %s%s\n",
 612                                             ng_bridge_nodename(node),
 613                                             NG_HOOK_NAME(hook), suffix);
 614                                 }
 615
 616                                 /* Mark link as linka non grata */
 617                                 link->loopCount = priv->conf.loopTimeout;
 618                                 link->stats.loopDetects++;
 619
 620                                 /* Forget all hosts on this link */
 621                                 ng_bridge_remove_hosts(priv, linkNum);
 622
 623                                 /* Drop packet */
 624                                 link->stats.loopDrops++;
 625                                 NG_FREE_ITEM(item);
 626                                 NG_FREE_M(m);
 627                                 return (ELOOP);         /* XXX appropriate? */
 628                         }
 629
 630                         /* Move host over to new link */
 631                         host->linkNum = linkNum;
 632                         host->age = 0;
 633                 }
 634         } else {
 635                 if (!ng_bridge_put(priv, eh->ether_shost, linkNum)) {
 636                         link->stats.memoryFailures++;
 637                         NG_FREE_ITEM(item);
 638                         NG_FREE_M(m);
 639                         return (ENOMEM);
 640                 }
 641         }
 642
 643         /* Run packet through ipfw processing, if enabled */
 644 #if 0
 645         if (priv->conf.ipfw[linkNum] && V_fw_enable && V_ip_fw_chk_ptr != NULL) {
 646                 /* XXX not implemented yet */
 647         }
 648 #endif
 649
 650         /*
 651          * If unicast and destination host known, deliver to host's link,
 652          * unless it is the same link as the packet came in on.
 653          */
 654         if (!manycast) {
 655
 656                 /* Determine packet destination link */
 657                 if ((host = ng_bridge_get(priv, eh->ether_dhost)) != NULL) {
 658                         struct ng_bridge_link *const destLink
 659                             = priv->links[host->linkNum];
 660
 661                         /* If destination same as incoming link, do nothing */
 662                         KASSERT(destLink != NULL,
 663                             ("%s: link%d null", __func__, host->linkNum));
 664                         if (destLink == link) {
 665                                 NG_FREE_ITEM(item);
 666                                 NG_FREE_M(m);
 667                                 return (0);
 668                         }
 669
 670                         /* Deliver packet out the destination link */
 671                         destLink->stats.xmitPackets++;
 672                         destLink->stats.xmitOctets += m->m_pkthdr.len;
 673                         NG_FWD_NEW_DATA(error, item, destLink->hook, m);
 674                         return (error);
 675                 }
 676
 677                 /* Destination host is not known */
 678                 link->stats.recvUnknown++;
 679         }
 680
 681         /* Distribute unknown, multicast, broadcast pkts to all other links */
 682         firstLink = NULL;
 683         for (linkNum = linksSeen = 0; linksSeen <= priv->numLinks; linkNum++) {
 684                 struct ng_bridge_link *destLink;
 685                 struct mbuf *m2 = NULL;
 686
 687                 /*
 688                  * If we have checked all the links then now
 689                  * send the original on its reserved link
 690                  */
 691                 if (linksSeen == priv->numLinks) {
 692                         /* If we never saw a good link, leave. */
 693                         if (firstLink == NULL) {
 694                                 NG_FREE_ITEM(item);
 695                                 NG_FREE_M(m);
 696                                 return (0);
 697                         }
 698                         destLink = firstLink;
 699                 } else {
 700                         destLink = priv->links[linkNum];
 701                         if (destLink != NULL)
 702                                 linksSeen++;
 703                         /* Skip incoming link and disconnected links */
 704                         if (destLink == NULL || destLink == link) {
 705                                 continue;
 706                         }
 707                         if (firstLink == NULL) {
 708                                 /*
 709                                  * This is the first usable link we have found.
 710                                  * Reserve it for the originals.
 711                                  * If we never find another we save a copy.
 712                                  */
 713                                 firstLink = destLink;
 714                                 continue;
 715                         }
 716
 717                         /*
 718                          * It's usable link but not the reserved (first) one.
 719                          * Copy mbuf info for sending.
 720                          */
 721                         m2 = m_dup(m, M_DONTWAIT);      /* XXX m_copypacket() */
 722                         if (m2 == NULL) {
 723                                 link->stats.memoryFailures++;
 724                                 NG_FREE_ITEM(item);
 725                                 NG_FREE_M(m);
 726                                 return (ENOBUFS);
 727                         }
 728                 }
 729
 730                 /* Update stats */
 731                 destLink->stats.xmitPackets++;
 732                 destLink->stats.xmitOctets += m->m_pkthdr.len;
 733                 switch (manycast) {
 734                 case 0:                                 /* unicast */
 735                         break;
 736                 case 1:                                 /* multicast */
 737                         destLink->stats.xmitMulticasts++;
 738                         break;
 739                 case 2:                                 /* broadcast */
 740                         destLink->stats.xmitBroadcasts++;
 741                         break;
 742                 }
 743
 744                 /* Send packet */
 745                 if (destLink == firstLink) {
 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(error, item, destLink->hook, m);
 751                         break; /* always done last - not really needed. */
 752                 } else {
 753                         NG_SEND_DATA_ONLY(error, destLink->hook, m2);
 754                 }
 755         }
 756         return (error);
 757 }
 758
 759 /*
 760  * Shutdown node
 761  */
 762 static int
 763 ng_bridge_shutdown(node_p node)
 764 {
 765         const priv_p priv = NG_NODE_PRIVATE(node);
 766
 767         /*
 768          * Shut down everything including the timer.  Even if the
 769          * callout has already been dequeued and is about to be
 770          * run, ng_bridge_timeout() won't be fired as the node
 771          * is already marked NGF_INVALID, so we're safe to free
 772          * the node now.
 773          */
 774         KASSERT(priv->numLinks == 0 && priv->numHosts == 0,
 775             ("%s: numLinks=%d numHosts=%d",
 776             __func__, priv->numLinks, priv->numHosts));
 777         ng_uncallout(&priv->timer, node);
 778         NG_NODE_SET_PRIVATE(node, NULL);
 779         NG_NODE_UNREF(node);
 780         free(priv->tab, M_NETGRAPH_BRIDGE);
 781         free(priv, M_NETGRAPH_BRIDGE);
 782         return (0);
 783 }
 784
 785 /*
 786  * Hook disconnection.
 787  */
 788 static int
 789 ng_bridge_disconnect(hook_p hook)
 790 {
 791         const priv_p priv = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
 792         int linkNum;
 793
 794         /* Get link number */
 795         linkNum = (intptr_t)NG_HOOK_PRIVATE(hook);
 796         KASSERT(linkNum >= 0 && linkNum < NG_BRIDGE_MAX_LINKS,
 797             ("%s: linkNum=%u", __func__, linkNum));
 798
 799         /* Remove all hosts associated with this link */
 800         ng_bridge_remove_hosts(priv, linkNum);
 801
 802         /* Free associated link information */
 803         KASSERT(priv->links[linkNum] != NULL, ("%s: no link", __func__));
 804         free(priv->links[linkNum], M_NETGRAPH_BRIDGE);
 805         priv->links[linkNum] = NULL;
 806         priv->numLinks--;
 807
 808         /* If no more hooks, go away */
 809         if ((NG_NODE_NUMHOOKS(NG_HOOK_NODE(hook)) == 0)
 810             && (NG_NODE_IS_VALID(NG_HOOK_NODE(hook)))
 811             && !priv->persistent) {
 812                 ng_rmnode_self(NG_HOOK_NODE(hook));
 813         }
 814         return (0);
 815 }
 816
 817 /******************************************************************
 818                     HASH TABLE FUNCTIONS
 819 ******************************************************************/
 820
 821 /*
 822  * Hash algorithm
 823  */
 824 #define HASH(addr,mask)         ( (((const u_int16_t *)(addr))[0]       \
 825                                  ^ ((const u_int16_t *)(addr))[1]       \
 826                                  ^ ((const u_int16_t *)(addr))[2]) & (mask) )
 827
 828 /*
 829  * Find a host entry in the table.
 830  */
 831 static struct ng_bridge_host *
 832 ng_bridge_get(priv_p priv, const u_char *addr)
 833 {
 834         const int bucket = HASH(addr, priv->hashMask);
 835         struct ng_bridge_hent *hent;
 836
 837         SLIST_FOREACH(hent, &priv->tab[bucket], next) {
 838                 if (ETHER_EQUAL(hent->host.addr, addr))
 839                         return (&hent->host);
 840         }
 841         return (NULL);
 842 }
 843
 844 /*
 845  * Add a new host entry to the table. This assumes the host doesn't
 846  * already exist in the table. Returns 1 on success, 0 if there
 847  * was a memory allocation failure.
 848  */
 849 static int
 850 ng_bridge_put(priv_p priv, const u_char *addr, int linkNum)
 851 {
 852         const int bucket = HASH(addr, priv->hashMask);
 853         struct ng_bridge_hent *hent;
 854
 855 #ifdef INVARIANTS
 856         /* Assert that entry does not already exist in hashtable */
 857         SLIST_FOREACH(hent, &priv->tab[bucket], next) {
 858                 KASSERT(!ETHER_EQUAL(hent->host.addr, addr),
 859                     ("%s: entry %6D exists in table", __func__, addr, ":"));
 860         }
 861 #endif
 862
 863         /* Allocate and initialize new hashtable entry */
 864         hent = malloc(sizeof(*hent), M_NETGRAPH_BRIDGE, M_NOWAIT);
 865         if (hent == NULL)
 866                 return (0);
 867         bcopy(addr, hent->host.addr, ETHER_ADDR_LEN);
 868         hent->host.linkNum = linkNum;
 869         hent->host.staleness = 0;
 870         hent->host.age = 0;
 871
 872         /* Add new element to hash bucket */
 873         SLIST_INSERT_HEAD(&priv->tab[bucket], hent, next);
 874         priv->numHosts++;
 875
 876         /* Resize table if necessary */
 877         ng_bridge_rehash(priv);
 878         return (1);
 879 }
 880
 881 /*
 882  * Resize the hash table. We try to maintain the number of buckets
 883  * such that the load factor is in the range 0.25 to 1.0.
 884  *
 885  * If we can't get the new memory then we silently fail. This is OK
 886  * because things will still work and we'll try again soon anyway.
 887  */
 888 static void
 889 ng_bridge_rehash(priv_p priv)
 890 {
 891         struct ng_bridge_bucket *newTab;
 892         int oldBucket, newBucket;
 893         int newNumBuckets;
 894         u_int newMask;
 895
 896         /* Is table too full or too empty? */
 897         if (priv->numHosts > priv->numBuckets
 898             && (priv->numBuckets << 1) <= MAX_BUCKETS)
 899                 newNumBuckets = priv->numBuckets << 1;
 900         else if (priv->numHosts < (priv->numBuckets >> 2)
 901             && (priv->numBuckets >> 2) >= MIN_BUCKETS)
 902                 newNumBuckets = priv->numBuckets >> 2;
 903         else
 904                 return;
 905         newMask = newNumBuckets - 1;
 906
 907         /* Allocate and initialize new table */
 908         newTab = malloc(newNumBuckets * sizeof(*newTab),
 909             M_NETGRAPH_BRIDGE, M_NOWAIT | M_ZERO);
 910         if (newTab == NULL)
 911                 return;
 912
 913         /* Move all entries from old table to new table */
 914         for (oldBucket = 0; oldBucket < priv->numBuckets; oldBucket++) {
 915                 struct ng_bridge_bucket *const oldList = &priv->tab[oldBucket];
 916
 917                 while (!SLIST_EMPTY(oldList)) {
 918                         struct ng_bridge_hent *const hent
 919                             = SLIST_FIRST(oldList);
 920
 921                         SLIST_REMOVE_HEAD(oldList, next);
 922                         newBucket = HASH(hent->host.addr, newMask);
 923                         SLIST_INSERT_HEAD(&newTab[newBucket], hent, next);
 924                 }
 925         }
 926
 927         /* Replace old table with new one */
 928         if (priv->conf.debugLevel >= 3) {
 929                 log(LOG_INFO, "ng_bridge: %s: table size %d -> %d\n",
 930                     ng_bridge_nodename(priv->node),
 931                     priv->numBuckets, newNumBuckets);
 932         }
 933         free(priv->tab, M_NETGRAPH_BRIDGE);
 934         priv->numBuckets = newNumBuckets;
 935         priv->hashMask = newMask;
 936         priv->tab = newTab;
 937         return;
 938 }
 939
 940 /******************************************************************
 941                     MISC FUNCTIONS
 942 ******************************************************************/
 943
 944 /*
 945  * Remove all hosts associated with a specific link from the hashtable.
 946  * If linkNum == -1, then remove all hosts in the table.
 947  */
 948 static void
 949 ng_bridge_remove_hosts(priv_p priv, int linkNum)
 950 {
 951         int bucket;
 952
 953         for (bucket = 0; bucket < priv->numBuckets; bucket++) {
 954                 struct ng_bridge_hent **hptr = &SLIST_FIRST(&priv->tab[bucket]);
 955
 956                 while (*hptr != NULL) {
 957                         struct ng_bridge_hent *const hent = *hptr;
 958
 959                         if (linkNum == -1 || hent->host.linkNum == linkNum) {
 960                                 *hptr = SLIST_NEXT(hent, next);
 961                                 free(hent, M_NETGRAPH_BRIDGE);
 962                                 priv->numHosts--;
 963                         } else
 964                                 hptr = &SLIST_NEXT(hent, next);
 965                 }
 966         }
 967 }
 968
 969 /*
 970  * Handle our once-per-second timeout event. We do two things:
 971  * we decrement link->loopCount for those links being muted due to
 972  * a detected loopback condition, and we remove any hosts from
 973  * the hashtable whom we haven't heard from in a long while.
 974  */
 975 static void
 976 ng_bridge_timeout(node_p node, hook_p hook, void *arg1, int arg2)
 977 {
 978         const priv_p priv = NG_NODE_PRIVATE(node);
 979         int bucket;
 980         int counter = 0;
 981         int linkNum;
 982
 983         /* Update host time counters and remove stale entries */
 984         for (bucket = 0; bucket < priv->numBuckets; bucket++) {
 985                 struct ng_bridge_hent **hptr = &SLIST_FIRST(&priv->tab[bucket]);
 986
 987                 while (*hptr != NULL) {
 988                         struct ng_bridge_hent *const hent = *hptr;
 989
 990                         /* Make sure host's link really exists */
 991                         KASSERT(priv->links[hent->host.linkNum] != NULL,
 992                             ("%s: host %6D on nonexistent link %d\n",
 993                             __func__, hent->host.addr, ":",
 994                             hent->host.linkNum));
 995
 996                         /* Remove hosts we haven't heard from in a while */
 997                         if (++hent->host.staleness >= priv->conf.maxStaleness) {
 998                                 *hptr = SLIST_NEXT(hent, next);
 999                                 free(hent, M_NETGRAPH_BRIDGE);
1000                                 priv->numHosts--;
1001                         } else {
1002                                 if (hent->host.age < 0xffff)
1003                                         hent->host.age++;
1004                                 hptr = &SLIST_NEXT(hent, next);
1005                                 counter++;
1006                         }
1007                 }
1008         }
1009         KASSERT(priv->numHosts == counter,
1010             ("%s: hosts: %d != %d", __func__, priv->numHosts, counter));
1011
1012         /* Decrease table size if necessary */
1013         ng_bridge_rehash(priv);
1014
1015         /* Decrease loop counter on muted looped back links */
1016         for (counter = linkNum = 0; linkNum < NG_BRIDGE_MAX_LINKS; linkNum++) {
1017                 struct ng_bridge_link *const link = priv->links[linkNum];
1018
1019                 if (link != NULL) {
1020                         if (link->loopCount != 0) {
1021                                 link->loopCount--;
1022                                 if (link->loopCount == 0
1023                                     && priv->conf.debugLevel >= 2) {
1024                                         log(LOG_INFO, "ng_bridge: %s:"
1025                                             " restoring looped back link%d\n",
1026                                             ng_bridge_nodename(node), linkNum);
1027                                 }
1028                         }
1029                         counter++;
1030                 }
1031         }
1032         KASSERT(priv->numLinks == counter,
1033             ("%s: links: %d != %d", __func__, priv->numLinks, counter));
1034
1035         /* Register a new timeout, keeping the existing node reference */
1036         ng_callout(&priv->timer, node, NULL, hz, ng_bridge_timeout, NULL, 0);
1037 }
1038
1039 /*
1040  * Return node's "name", even if it doesn't have one.
1041  */
1042 static const char *
1043 ng_bridge_nodename(node_p node)
1044 {
1045         static char name[NG_NODESIZ];
1046
1047         if (NG_NODE_NAME(node) != NULL)
1048                 snprintf(name, sizeof(name), "%s", NG_NODE_NAME(node));
1049         else
1050                 snprintf(name, sizeof(name), "[%x]", ng_node2ID(node));
1051         return name;
1052 }
1053