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/if_var.h>
  75 #include <net/ethernet.h>
  76 #include <net/vnet.h>
  77
  78 #include <netinet/in.h>
  79 #if 0   /* not used yet */
  80 #include <netinet/ip_fw.h>
  81 #endif
  82 #include <netgraph/ng_message.h>
  83 #include <netgraph/netgraph.h>
  84 #include <netgraph/ng_parse.h>
  85 #include <netgraph/ng_bridge.h>
  86
  87 #ifdef NG_SEPARATE_MALLOC
  88 static MALLOC_DEFINE(M_NETGRAPH_BRIDGE, "netgraph_bridge",
  89     "netgraph bridge node");
  90 #else
  91 #define M_NETGRAPH_BRIDGE M_NETGRAPH
  92 #endif
  93
  94 /* Per-link private data */
  95 struct ng_bridge_link {
  96         hook_p                          hook;           /* netgraph hook */
  97         u_int16_t                       loopCount;      /* loop ignore timer */
  98         struct ng_bridge_link_stats     stats;          /* link stats */
  99 };
 100
 101 /* Per-node private data */
 102 struct ng_bridge_private {
 103         struct ng_bridge_bucket *tab;           /* hash table bucket array */
 104         struct ng_bridge_link   *links[NG_BRIDGE_MAX_LINKS];
 105         struct ng_bridge_config conf;           /* node configuration */
 106         node_p                  node;           /* netgraph node */
 107         u_int                   numHosts;       /* num entries in table */
 108         u_int                   numBuckets;     /* num buckets in table */
 109         u_int                   hashMask;       /* numBuckets - 1 */
 110         int                     numLinks;       /* num connected links */
 111         int                     persistent;     /* can exist w/o hooks */
 112         struct callout          timer;          /* one second periodic timer */
 113 };
 114 typedef struct ng_bridge_private *priv_p;
 115
 116 /* Information about a host, stored in a hash table entry */
 117 struct ng_bridge_hent {
 118         struct ng_bridge_host           host;   /* actual host info */
 119         SLIST_ENTRY(ng_bridge_hent)     next;   /* next entry in bucket */
 120 };
 121
 122 /* Hash table bucket declaration */
 123 SLIST_HEAD(ng_bridge_bucket, ng_bridge_hent);
 124
 125 /* Netgraph node methods */
 126 static ng_constructor_t ng_bridge_constructor;
 127 static ng_rcvmsg_t      ng_bridge_rcvmsg;
 128 static ng_shutdown_t    ng_bridge_shutdown;
 129 static ng_newhook_t     ng_bridge_newhook;
 130 static ng_rcvdata_t     ng_bridge_rcvdata;
 131 static ng_disconnect_t  ng_bridge_disconnect;
 132
 133 /* Other internal functions */
 134 static struct   ng_bridge_host *ng_bridge_get(priv_p priv, const u_char *addr);
 135 static int      ng_bridge_put(priv_p priv, const u_char *addr, int linkNum);
 136 static void     ng_bridge_rehash(priv_p priv);
 137 static void     ng_bridge_remove_hosts(priv_p priv, int linkNum);
 138 static void     ng_bridge_timeout(node_p node, hook_p hook, void *arg1, int arg2);
 139 static const    char *ng_bridge_nodename(node_p node);
 140
 141 /* Ethernet broadcast */
 142 static const u_char ng_bridge_bcast_addr[ETHER_ADDR_LEN] =
 143     { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
 144
 145 /* Store each hook's link number in the private field */
 146 #define LINK_NUM(hook)          (*(u_int16_t *)(&(hook)->private))
 147
 148 /* Compare Ethernet addresses using 32 and 16 bit words instead of bytewise */
 149 #define ETHER_EQUAL(a,b)        (((const u_int32_t *)(a))[0] \
 150                                         == ((const u_int32_t *)(b))[0] \
 151                                     && ((const u_int16_t *)(a))[2] \
 152                                         == ((const u_int16_t *)(b))[2])
 153
 154 /* Minimum and maximum number of hash buckets. Must be a power of two. */
 155 #define MIN_BUCKETS             (1 << 5)        /* 32 */
 156 #define MAX_BUCKETS             (1 << 14)       /* 16384 */
 157
 158 /* Configuration default values */
 159 #define DEFAULT_LOOP_TIMEOUT    60
 160 #define DEFAULT_MAX_STALENESS   (15 * 60)       /* same as ARP timeout */
 161 #define DEFAULT_MIN_STABLE_AGE  1
 162
 163 /******************************************************************
 164                     NETGRAPH PARSE TYPES
 165 ******************************************************************/
 166
 167 /*
 168  * How to determine the length of the table returned by NGM_BRIDGE_GET_TABLE
 169  */
 170 static int
 171 ng_bridge_getTableLength(const struct ng_parse_type *type,
 172         const u_char *start, const u_char *buf)
 173 {
 174         const struct ng_bridge_host_ary *const hary
 175             = (const struct ng_bridge_host_ary *)(buf - sizeof(u_int32_t));
 176
 177         return hary->numHosts;
 178 }
 179
 180 /* Parse type for struct ng_bridge_host_ary */
 181 static const struct ng_parse_struct_field ng_bridge_host_type_fields[]
 182         = NG_BRIDGE_HOST_TYPE_INFO(&ng_parse_enaddr_type);
 183 static const struct ng_parse_type ng_bridge_host_type = {
 184         &ng_parse_struct_type,
 185         &ng_bridge_host_type_fields
 186 };
 187 static const struct ng_parse_array_info ng_bridge_hary_type_info = {
 188         &ng_bridge_host_type,
 189         ng_bridge_getTableLength
 190 };
 191 static const struct ng_parse_type ng_bridge_hary_type = {
 192         &ng_parse_array_type,
 193         &ng_bridge_hary_type_info
 194 };
 195 static const struct ng_parse_struct_field ng_bridge_host_ary_type_fields[]
 196         = NG_BRIDGE_HOST_ARY_TYPE_INFO(&ng_bridge_hary_type);
 197 static const struct ng_parse_type ng_bridge_host_ary_type = {
 198         &ng_parse_struct_type,
 199         &ng_bridge_host_ary_type_fields
 200 };
 201
 202 /* Parse type for struct ng_bridge_config */
 203 static const struct ng_parse_fixedarray_info ng_bridge_ipfwary_type_info = {
 204         &ng_parse_uint8_type,
 205         NG_BRIDGE_MAX_LINKS
 206 };
 207 static const struct ng_parse_type ng_bridge_ipfwary_type = {
 208         &ng_parse_fixedarray_type,
 209         &ng_bridge_ipfwary_type_info
 210 };
 211 static const struct ng_parse_struct_field ng_bridge_config_type_fields[]
 212         = NG_BRIDGE_CONFIG_TYPE_INFO(&ng_bridge_ipfwary_type);
 213 static const struct ng_parse_type ng_bridge_config_type = {
 214         &ng_parse_struct_type,
 215         &ng_bridge_config_type_fields
 216 };
 217
 218 /* Parse type for struct ng_bridge_link_stat */
 219 static const struct ng_parse_struct_field ng_bridge_stats_type_fields[]
 220         = NG_BRIDGE_STATS_TYPE_INFO;
 221 static const struct ng_parse_type ng_bridge_stats_type = {
 222         &ng_parse_struct_type,
 223         &ng_bridge_stats_type_fields
 224 };
 225
 226 /* List of commands and how to convert arguments to/from ASCII */
 227 static const struct ng_cmdlist ng_bridge_cmdlist[] = {
 228         {
 229           NGM_BRIDGE_COOKIE,
 230           NGM_BRIDGE_SET_CONFIG,
 231           "setconfig",
 232           &ng_bridge_config_type,
 233           NULL
 234         },
 235         {
 236           NGM_BRIDGE_COOKIE,
 237           NGM_BRIDGE_GET_CONFIG,
 238           "getconfig",
 239           NULL,
 240           &ng_bridge_config_type
 241         },
 242         {
 243           NGM_BRIDGE_COOKIE,
 244           NGM_BRIDGE_RESET,
 245           "reset",
 246           NULL,
 247           NULL
 248         },
 249         {
 250           NGM_BRIDGE_COOKIE,
 251           NGM_BRIDGE_GET_STATS,
 252           "getstats",
 253           &ng_parse_uint32_type,
 254           &ng_bridge_stats_type
 255         },
 256         {
 257           NGM_BRIDGE_COOKIE,
 258           NGM_BRIDGE_CLR_STATS,
 259           "clrstats",
 260           &ng_parse_uint32_type,
 261           NULL
 262         },
 263         {
 264           NGM_BRIDGE_COOKIE,
 265           NGM_BRIDGE_GETCLR_STATS,
 266           "getclrstats",
 267           &ng_parse_uint32_type,
 268           &ng_bridge_stats_type
 269         },
 270         {
 271           NGM_BRIDGE_COOKIE,
 272           NGM_BRIDGE_GET_TABLE,
 273           "gettable",
 274           NULL,
 275           &ng_bridge_host_ary_type
 276         },
 277         {
 278           NGM_BRIDGE_COOKIE,
 279           NGM_BRIDGE_SET_PERSISTENT,
 280           "setpersistent",
 281           NULL,
 282           NULL
 283         },
 284         { 0 }
 285 };
 286
 287 /* Node type descriptor */
 288 static struct ng_type ng_bridge_typestruct = {
 289         .version =      NG_ABI_VERSION,
 290         .name =         NG_BRIDGE_NODE_TYPE,
 291         .constructor =  ng_bridge_constructor,
 292         .rcvmsg =       ng_bridge_rcvmsg,
 293         .shutdown =     ng_bridge_shutdown,
 294         .newhook =      ng_bridge_newhook,
 295         .rcvdata =      ng_bridge_rcvdata,
 296         .disconnect =   ng_bridge_disconnect,
 297         .cmdlist =      ng_bridge_cmdlist,
 298 };
 299 NETGRAPH_INIT(bridge, &ng_bridge_typestruct);
 300
 301 /******************************************************************
 302                     NETGRAPH NODE METHODS
 303 ******************************************************************/
 304
 305 /*
 306  * Node constructor
 307  */
 308 static int
 309 ng_bridge_constructor(node_p node)
 310 {
 311         priv_p priv;
 312
 313         /* Allocate and initialize private info */
 314         priv = malloc(sizeof(*priv), M_NETGRAPH_BRIDGE, M_WAITOK | M_ZERO);
 315         ng_callout_init(&priv->timer);
 316
 317         /* Allocate and initialize hash table, etc. */
 318         priv->tab = malloc(MIN_BUCKETS * sizeof(*priv->tab),
 319             M_NETGRAPH_BRIDGE, M_WAITOK | M_ZERO);
 320         priv->numBuckets = MIN_BUCKETS;
 321         priv->hashMask = MIN_BUCKETS - 1;
 322         priv->conf.debugLevel = 1;
 323         priv->conf.loopTimeout = DEFAULT_LOOP_TIMEOUT;
 324         priv->conf.maxStaleness = DEFAULT_MAX_STALENESS;
 325         priv->conf.minStableAge = DEFAULT_MIN_STABLE_AGE;
 326
 327         /*
 328          * This node has all kinds of stuff that could be screwed by SMP.
 329          * Until it gets it's own internal protection, we go through in
 330          * single file. This could hurt a machine bridging between two
 331          * GB ethernets so it should be fixed.
 332          * When it's fixed the process SHOULD NOT SLEEP, spinlocks please!
 333          * (and atomic ops )
 334          */
 335         NG_NODE_FORCE_WRITER(node);
 336         NG_NODE_SET_PRIVATE(node, priv);
 337         priv->node = node;
 338
 339         /* Start timer; timer is always running while node is alive */
 340         ng_callout(&priv->timer, node, NULL, hz, ng_bridge_timeout, NULL, 0);
 341
 342         /* Done */
 343         return (0);
 344 }
 345
 346 /*
 347  * Method for attaching a new hook
 348  */
 349 static  int
 350 ng_bridge_newhook(node_p node, hook_p hook, const char *name)
 351 {
 352         const priv_p priv = NG_NODE_PRIVATE(node);
 353
 354         /* Check for a link hook */
 355         if (strncmp(name, NG_BRIDGE_HOOK_LINK_PREFIX,
 356             strlen(NG_BRIDGE_HOOK_LINK_PREFIX)) == 0) {
 357                 const char *cp;
 358                 char *eptr;
 359                 u_long linkNum;
 360
 361                 cp = name + strlen(NG_BRIDGE_HOOK_LINK_PREFIX);
 362                 if (!isdigit(*cp) || (cp[0] == '0' && cp[1] != '\0'))
 363                         return (EINVAL);
 364                 linkNum = strtoul(cp, &eptr, 10);
 365                 if (*eptr != '\0' || linkNum >= NG_BRIDGE_MAX_LINKS)
 366                         return (EINVAL);
 367                 if (priv->links[linkNum] != NULL)
 368                         return (EISCONN);
 369                 priv->links[linkNum] = malloc(sizeof(*priv->links[linkNum]),
 370                     M_NETGRAPH_BRIDGE, M_NOWAIT|M_ZERO);
 371                 if (priv->links[linkNum] == NULL)
 372                         return (ENOMEM);
 373                 priv->links[linkNum]->hook = hook;
 374                 NG_HOOK_SET_PRIVATE(hook, (void *)linkNum);
 375                 priv->numLinks++;
 376                 return (0);
 377         }
 378
 379         /* Unknown hook name */
 380         return (EINVAL);
 381 }
 382
 383 /*
 384  * Receive a control message
 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                         int i;
 416
 417                         if (msg->header.arglen
 418                             != sizeof(struct ng_bridge_config)) {
 419                                 error = EINVAL;
 420                                 break;
 421                         }
 422                         conf = (struct ng_bridge_config *)msg->data;
 423                         priv->conf = *conf;
 424                         for (i = 0; i < NG_BRIDGE_MAX_LINKS; i++)
 425                                 priv->conf.ipfw[i] = !!priv->conf.ipfw[i];
 426                         break;
 427                     }
 428                 case NGM_BRIDGE_RESET:
 429                     {
 430                         int i;
 431
 432                         /* Flush all entries in the hash table */
 433                         ng_bridge_remove_hosts(priv, -1);
 434
 435                         /* Reset all loop detection counters and stats */
 436                         for (i = 0; i < NG_BRIDGE_MAX_LINKS; i++) {
 437                                 if (priv->links[i] == NULL)
 438                                         continue;
 439                                 priv->links[i]->loopCount = 0;
 440                                 bzero(&priv->links[i]->stats,
 441                                     sizeof(priv->links[i]->stats));
 442                         }
 443                         break;
 444                     }
 445                 case NGM_BRIDGE_GET_STATS:
 446                 case NGM_BRIDGE_CLR_STATS:
 447                 case NGM_BRIDGE_GETCLR_STATS:
 448                     {
 449                         struct ng_bridge_link *link;
 450                         int linkNum;
 451
 452                         /* Get link number */
 453                         if (msg->header.arglen != sizeof(u_int32_t)) {
 454                                 error = EINVAL;
 455                                 break;
 456                         }
 457                         linkNum = *((u_int32_t *)msg->data);
 458                         if (linkNum < 0 || linkNum >= NG_BRIDGE_MAX_LINKS) {
 459                                 error = EINVAL;
 460                                 break;
 461                         }
 462                         if ((link = priv->links[linkNum]) == NULL) {
 463                                 error = ENOTCONN;
 464                                 break;
 465                         }
 466
 467                         /* Get/clear stats */
 468                         if (msg->header.cmd != NGM_BRIDGE_CLR_STATS) {
 469                                 NG_MKRESPONSE(resp, msg,
 470                                     sizeof(link->stats), M_NOWAIT);
 471                                 if (resp == NULL) {
 472                                         error = ENOMEM;
 473                                         break;
 474                                 }
 475                                 bcopy(&link->stats,
 476                                     resp->data, sizeof(link->stats));
 477                         }
 478                         if (msg->header.cmd != NGM_BRIDGE_GET_STATS)
 479                                 bzero(&link->stats, sizeof(link->stats));
 480                         break;
 481                     }
 482                 case NGM_BRIDGE_GET_TABLE:
 483                     {
 484                         struct ng_bridge_host_ary *ary;
 485                         struct ng_bridge_hent *hent;
 486                         int i = 0, bucket;
 487
 488                         NG_MKRESPONSE(resp, msg, sizeof(*ary)
 489                             + (priv->numHosts * sizeof(*ary->hosts)), M_NOWAIT);
 490                         if (resp == NULL) {
 491                                 error = ENOMEM;
 492                                 break;
 493                         }
 494                         ary = (struct ng_bridge_host_ary *)resp->data;
 495                         ary->numHosts = priv->numHosts;
 496                         for (bucket = 0; bucket < priv->numBuckets; bucket++) {
 497                                 SLIST_FOREACH(hent, &priv->tab[bucket], next)
 498                                         ary->hosts[i++] = hent->host;
 499                         }
 500                         break;
 501                     }
 502                 case NGM_BRIDGE_SET_PERSISTENT:
 503                     {
 504                         priv->persistent = 1;
 505                         break;
 506                     }
 507                 default:
 508                         error = EINVAL;
 509                         break;
 510                 }
 511                 break;
 512         default:
 513                 error = EINVAL;
 514                 break;
 515         }
 516
 517         /* Done */
 518         NG_RESPOND_MSG(error, node, item, resp);
 519         NG_FREE_MSG(msg);
 520         return (error);
 521 }
 522
 523 /*
 524  * Receive data on a hook
 525  */
 526 static int
 527 ng_bridge_rcvdata(hook_p hook, item_p item)
 528 {
 529         const node_p node = NG_HOOK_NODE(hook);
 530         const priv_p priv = NG_NODE_PRIVATE(node);
 531         struct ng_bridge_host *host;
 532         struct ng_bridge_link *link;
 533         struct ether_header *eh;
 534         int error = 0, linkNum, linksSeen;
 535         int manycast;
 536         struct mbuf *m;
 537         struct ng_bridge_link *firstLink;
 538
 539         NGI_GET_M(item, m);
 540         /* Get link number */
 541         linkNum = (intptr_t)NG_HOOK_PRIVATE(hook);
 542         KASSERT(linkNum >= 0 && linkNum < NG_BRIDGE_MAX_LINKS,
 543             ("%s: linkNum=%u", __func__, linkNum));
 544         link = priv->links[linkNum];
 545         KASSERT(link != NULL, ("%s: link%d null", __func__, linkNum));
 546
 547         /* Sanity check packet and pull up header */
 548         if (m->m_pkthdr.len < ETHER_HDR_LEN) {
 549                 link->stats.recvRunts++;
 550                 NG_FREE_ITEM(item);
 551                 NG_FREE_M(m);
 552                 return (EINVAL);
 553         }
 554         if (m->m_len < ETHER_HDR_LEN && !(m = m_pullup(m, ETHER_HDR_LEN))) {
 555                 link->stats.memoryFailures++;
 556                 NG_FREE_ITEM(item);
 557                 return (ENOBUFS);
 558         }
 559         eh = mtod(m, struct ether_header *);
 560         if ((eh->ether_shost[0] & 1) != 0) {
 561                 link->stats.recvInvalid++;
 562                 NG_FREE_ITEM(item);
 563                 NG_FREE_M(m);
 564                 return (EINVAL);
 565         }
 566
 567         /* Is link disabled due to a loopback condition? */
 568         if (link->loopCount != 0) {
 569                 link->stats.loopDrops++;
 570                 NG_FREE_ITEM(item);
 571                 NG_FREE_M(m);
 572                 return (ELOOP);         /* XXX is this an appropriate error? */
 573         }
 574
 575         /* Update stats */
 576         link->stats.recvPackets++;
 577         link->stats.recvOctets += m->m_pkthdr.len;
 578         if ((manycast = (eh->ether_dhost[0] & 1)) != 0) {
 579                 if (ETHER_EQUAL(eh->ether_dhost, ng_bridge_bcast_addr)) {
 580                         link->stats.recvBroadcasts++;
 581                         manycast = 2;
 582                 } else
 583                         link->stats.recvMulticasts++;
 584         }
 585
 586         /* Look up packet's source Ethernet address in hashtable */
 587         if ((host = ng_bridge_get(priv, eh->ether_shost)) != NULL) {
 588
 589                 /* Update time since last heard from this host */
 590                 host->staleness = 0;
 591
 592                 /* Did host jump to a different link? */
 593                 if (host->linkNum != linkNum) {
 594
 595                         /*
 596                          * If the host's old link was recently established
 597                          * on the old link and it's already jumped to a new
 598                          * link, declare a loopback condition.
 599                          */
 600                         if (host->age < priv->conf.minStableAge) {
 601
 602                                 /* Log the problem */
 603                                 if (priv->conf.debugLevel >= 2) {
 604                                         struct ifnet *ifp = m->m_pkthdr.rcvif;
 605                                         char suffix[32];
 606
 607                                         if (ifp != NULL)
 608                                                 snprintf(suffix, sizeof(suffix),
 609                                                     " (%s)", ifp->if_xname);
 610                                         else
 611                                                 *suffix = '\0';
 612                                         log(LOG_WARNING, "ng_bridge: %s:"
 613                                             " loopback detected on %s%s\n",
 614                                             ng_bridge_nodename(node),
 615                                             NG_HOOK_NAME(hook), suffix);
 616                                 }
 617
 618                                 /* Mark link as linka non grata */
 619                                 link->loopCount = priv->conf.loopTimeout;
 620                                 link->stats.loopDetects++;
 621
 622                                 /* Forget all hosts on this link */
 623                                 ng_bridge_remove_hosts(priv, linkNum);
 624
 625                                 /* Drop packet */
 626                                 link->stats.loopDrops++;
 627                                 NG_FREE_ITEM(item);
 628                                 NG_FREE_M(m);
 629                                 return (ELOOP);         /* XXX appropriate? */
 630                         }
 631
 632                         /* Move host over to new link */
 633                         host->linkNum = linkNum;
 634                         host->age = 0;
 635                 }
 636         } else {
 637                 if (!ng_bridge_put(priv, eh->ether_shost, linkNum)) {
 638                         link->stats.memoryFailures++;
 639                         NG_FREE_ITEM(item);
 640                         NG_FREE_M(m);
 641                         return (ENOMEM);
 642                 }
 643         }
 644
 645         /* Run packet through ipfw processing, if enabled */
 646 #if 0
 647         if (priv->conf.ipfw[linkNum] && V_fw_enable && V_ip_fw_chk_ptr != NULL) {
 648                 /* XXX not implemented yet */
 649         }
 650 #endif
 651
 652         /*
 653          * If unicast and destination host known, deliver to host's link,
 654          * unless it is the same link as the packet came in on.
 655          */
 656         if (!manycast) {
 657
 658                 /* Determine packet destination link */
 659                 if ((host = ng_bridge_get(priv, eh->ether_dhost)) != NULL) {
 660                         struct ng_bridge_link *const destLink
 661                             = priv->links[host->linkNum];
 662
 663                         /* If destination same as incoming link, do nothing */
 664                         KASSERT(destLink != NULL,
 665                             ("%s: link%d null", __func__, host->linkNum));
 666                         if (destLink == link) {
 667                                 NG_FREE_ITEM(item);
 668                                 NG_FREE_M(m);
 669                                 return (0);
 670                         }
 671
 672                         /* Deliver packet out the destination link */
 673                         destLink->stats.xmitPackets++;
 674                         destLink->stats.xmitOctets += m->m_pkthdr.len;
 675                         NG_FWD_NEW_DATA(error, item, destLink->hook, m);
 676                         return (error);
 677                 }
 678
 679                 /* Destination host is not known */
 680                 link->stats.recvUnknown++;
 681         }
 682
 683         /* Distribute unknown, multicast, broadcast pkts to all other links */
 684         firstLink = NULL;
 685         for (linkNum = linksSeen = 0; linksSeen <= priv->numLinks; linkNum++) {
 686                 struct ng_bridge_link *destLink;
 687                 struct mbuf *m2 = NULL;
 688
 689                 /*
 690                  * If we have checked all the links then now
 691                  * send the original on its reserved link
 692                  */
 693                 if (linksSeen == priv->numLinks) {
 694                         /* If we never saw a good link, leave. */
 695                         if (firstLink == NULL) {
 696                                 NG_FREE_ITEM(item);
 697                                 NG_FREE_M(m);
 698                                 return (0);
 699                         }
 700                         destLink = firstLink;
 701                 } else {
 702                         destLink = priv->links[linkNum];
 703                         if (destLink != NULL)
 704                                 linksSeen++;
 705                         /* Skip incoming link and disconnected links */
 706                         if (destLink == NULL || destLink == link) {
 707                                 continue;
 708                         }
 709                         if (firstLink == NULL) {
 710                                 /*
 711                                  * This is the first usable link we have found.
 712                                  * Reserve it for the originals.
 713                                  * If we never find another we save a copy.
 714                                  */
 715                                 firstLink = destLink;
 716                                 continue;
 717                         }
 718
 719                         /*
 720                          * It's usable link but not the reserved (first) one.
 721                          * Copy mbuf info for sending.
 722                          */
 723                         m2 = m_dup(m, M_NOWAIT);        /* XXX m_copypacket() */
 724                         if (m2 == NULL) {
 725                                 link->stats.memoryFailures++;
 726                                 NG_FREE_ITEM(item);
 727                                 NG_FREE_M(m);
 728                                 return (ENOBUFS);
 729                         }
 730                 }
 731
 732                 /* Update stats */
 733                 destLink->stats.xmitPackets++;
 734                 destLink->stats.xmitOctets += m->m_pkthdr.len;
 735                 switch (manycast) {
 736                 case 0:                                 /* unicast */
 737                         break;
 738                 case 1:                                 /* multicast */
 739                         destLink->stats.xmitMulticasts++;
 740                         break;
 741                 case 2:                                 /* broadcast */
 742                         destLink->stats.xmitBroadcasts++;
 743                         break;
 744                 }
 745
 746                 /* Send packet */
 747                 if (destLink == firstLink) {
 748                         /*
 749                          * If we've sent all the others, send the original
 750                          * on the first link we found.
 751                          */
 752                         NG_FWD_NEW_DATA(error, item, destLink->hook, m);
 753                         break; /* always done last - not really needed. */
 754                 } else {
 755                         NG_SEND_DATA_ONLY(error, destLink->hook, m2);
 756                 }
 757         }
 758         return (error);
 759 }
 760
 761 /*
 762  * Shutdown node
 763  */
 764 static int
 765 ng_bridge_shutdown(node_p node)
 766 {
 767         const priv_p priv = NG_NODE_PRIVATE(node);
 768
 769         /*
 770          * Shut down everything including the timer.  Even if the
 771          * callout has already been dequeued and is about to be
 772          * run, ng_bridge_timeout() won't be fired as the node
 773          * is already marked NGF_INVALID, so we're safe to free
 774          * the node now.
 775          */
 776         KASSERT(priv->numLinks == 0 && priv->numHosts == 0,
 777             ("%s: numLinks=%d numHosts=%d",
 778             __func__, priv->numLinks, priv->numHosts));
 779         ng_uncallout(&priv->timer, node);
 780         NG_NODE_SET_PRIVATE(node, NULL);
 781         NG_NODE_UNREF(node);
 782         free(priv->tab, M_NETGRAPH_BRIDGE);
 783         free(priv, M_NETGRAPH_BRIDGE);
 784         return (0);
 785 }
 786
 787 /*
 788  * Hook disconnection.
 789  */
 790 static int
 791 ng_bridge_disconnect(hook_p hook)
 792 {
 793         const priv_p priv = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
 794         int linkNum;
 795
 796         /* Get link number */
 797         linkNum = (intptr_t)NG_HOOK_PRIVATE(hook);
 798         KASSERT(linkNum >= 0 && linkNum < NG_BRIDGE_MAX_LINKS,
 799             ("%s: linkNum=%u", __func__, linkNum));
 800
 801         /* Remove all hosts associated with this link */
 802         ng_bridge_remove_hosts(priv, linkNum);
 803
 804         /* Free associated link information */
 805         KASSERT(priv->links[linkNum] != NULL, ("%s: no link", __func__));
 806         free(priv->links[linkNum], M_NETGRAPH_BRIDGE);
 807         priv->links[linkNum] = NULL;
 808         priv->numLinks--;
 809
 810         /* If no more hooks, go away */
 811         if ((NG_NODE_NUMHOOKS(NG_HOOK_NODE(hook)) == 0)
 812             && (NG_NODE_IS_VALID(NG_HOOK_NODE(hook)))
 813             && !priv->persistent) {
 814                 ng_rmnode_self(NG_HOOK_NODE(hook));
 815         }
 816         return (0);
 817 }
 818
 819 /******************************************************************
 820                     HASH TABLE FUNCTIONS
 821 ******************************************************************/
 822
 823 /*
 824  * Hash algorithm
 825  */
 826 #define HASH(addr,mask)         ( (((const u_int16_t *)(addr))[0]       \
 827                                  ^ ((const u_int16_t *)(addr))[1]       \
 828                                  ^ ((const u_int16_t *)(addr))[2]) & (mask) )
 829
 830 /*
 831  * Find a host entry in the table.
 832  */
 833 static struct ng_bridge_host *
 834 ng_bridge_get(priv_p priv, const u_char *addr)
 835 {
 836         const int bucket = HASH(addr, priv->hashMask);
 837         struct ng_bridge_hent *hent;
 838
 839         SLIST_FOREACH(hent, &priv->tab[bucket], next) {
 840                 if (ETHER_EQUAL(hent->host.addr, addr))
 841                         return (&hent->host);
 842         }
 843         return (NULL);
 844 }
 845
 846 /*
 847  * Add a new host entry to the table. This assumes the host doesn't
 848  * already exist in the table. Returns 1 on success, 0 if there
 849  * was a memory allocation failure.
 850  */
 851 static int
 852 ng_bridge_put(priv_p priv, const u_char *addr, int linkNum)
 853 {
 854         const int bucket = HASH(addr, priv->hashMask);
 855         struct ng_bridge_hent *hent;
 856
 857 #ifdef INVARIANTS
 858         /* Assert that entry does not already exist in hashtable */
 859         SLIST_FOREACH(hent, &priv->tab[bucket], next) {
 860                 KASSERT(!ETHER_EQUAL(hent->host.addr, addr),
 861                     ("%s: entry %6D exists in table", __func__, addr, ":"));
 862         }
 863 #endif
 864
 865         /* Allocate and initialize new hashtable entry */
 866         hent = malloc(sizeof(*hent), M_NETGRAPH_BRIDGE, M_NOWAIT);
 867         if (hent == NULL)
 868                 return (0);
 869         bcopy(addr, hent->host.addr, ETHER_ADDR_LEN);
 870         hent->host.linkNum = linkNum;
 871         hent->host.staleness = 0;
 872         hent->host.age = 0;
 873
 874         /* Add new element to hash bucket */
 875         SLIST_INSERT_HEAD(&priv->tab[bucket], hent, next);
 876         priv->numHosts++;
 877
 878         /* Resize table if necessary */
 879         ng_bridge_rehash(priv);
 880         return (1);
 881 }
 882
 883 /*
 884  * Resize the hash table. We try to maintain the number of buckets
 885  * such that the load factor is in the range 0.25 to 1.0.
 886  *
 887  * If we can't get the new memory then we silently fail. This is OK
 888  * because things will still work and we'll try again soon anyway.
 889  */
 890 static void
 891 ng_bridge_rehash(priv_p priv)
 892 {
 893         struct ng_bridge_bucket *newTab;
 894         int oldBucket, newBucket;
 895         int newNumBuckets;
 896         u_int newMask;
 897
 898         /* Is table too full or too empty? */
 899         if (priv->numHosts > priv->numBuckets
 900             && (priv->numBuckets << 1) <= MAX_BUCKETS)
 901                 newNumBuckets = priv->numBuckets << 1;
 902         else if (priv->numHosts < (priv->numBuckets >> 2)
 903             && (priv->numBuckets >> 2) >= MIN_BUCKETS)
 904                 newNumBuckets = priv->numBuckets >> 2;
 905         else
 906                 return;
 907         newMask = newNumBuckets - 1;
 908
 909         /* Allocate and initialize new table */
 910         newTab = malloc(newNumBuckets * sizeof(*newTab),
 911             M_NETGRAPH_BRIDGE, M_NOWAIT | M_ZERO);
 912         if (newTab == NULL)
 913                 return;
 914
 915         /* Move all entries from old table to new table */
 916         for (oldBucket = 0; oldBucket < priv->numBuckets; oldBucket++) {
 917                 struct ng_bridge_bucket *const oldList = &priv->tab[oldBucket];
 918
 919                 while (!SLIST_EMPTY(oldList)) {
 920                         struct ng_bridge_hent *const hent
 921                             = SLIST_FIRST(oldList);
 922
 923                         SLIST_REMOVE_HEAD(oldList, next);
 924                         newBucket = HASH(hent->host.addr, newMask);
 925                         SLIST_INSERT_HEAD(&newTab[newBucket], hent, next);
 926                 }
 927         }
 928
 929         /* Replace old table with new one */
 930         if (priv->conf.debugLevel >= 3) {
 931                 log(LOG_INFO, "ng_bridge: %s: table size %d -> %d\n",
 932                     ng_bridge_nodename(priv->node),
 933                     priv->numBuckets, newNumBuckets);
 934         }
 935         free(priv->tab, M_NETGRAPH_BRIDGE);
 936         priv->numBuckets = newNumBuckets;
 937         priv->hashMask = newMask;
 938         priv->tab = newTab;
 939         return;
 940 }
 941
 942 /******************************************************************
 943                     MISC FUNCTIONS
 944 ******************************************************************/
 945
 946 /*
 947  * Remove all hosts associated with a specific link from the hashtable.
 948  * If linkNum == -1, then remove all hosts in the table.
 949  */
 950 static void
 951 ng_bridge_remove_hosts(priv_p priv, int linkNum)
 952 {
 953         int bucket;
 954
 955         for (bucket = 0; bucket < priv->numBuckets; bucket++) {
 956                 struct ng_bridge_hent **hptr = &SLIST_FIRST(&priv->tab[bucket]);
 957
 958                 while (*hptr != NULL) {
 959                         struct ng_bridge_hent *const hent = *hptr;
 960
 961                         if (linkNum == -1 || hent->host.linkNum == linkNum) {
 962                                 *hptr = SLIST_NEXT(hent, next);
 963                                 free(hent, M_NETGRAPH_BRIDGE);
 964                                 priv->numHosts--;
 965                         } else
 966                                 hptr = &SLIST_NEXT(hent, next);
 967                 }
 968         }
 969 }
 970
 971 /*
 972  * Handle our once-per-second timeout event. We do two things:
 973  * we decrement link->loopCount for those links being muted due to
 974  * a detected loopback condition, and we remove any hosts from
 975  * the hashtable whom we haven't heard from in a long while.
 976  */
 977 static void
 978 ng_bridge_timeout(node_p node, hook_p hook, void *arg1, int arg2)
 979 {
 980         const priv_p priv = NG_NODE_PRIVATE(node);
 981         int bucket;
 982         int counter = 0;
 983         int linkNum;
 984
 985         /* Update host time counters and remove stale entries */
 986         for (bucket = 0; bucket < priv->numBuckets; bucket++) {
 987                 struct ng_bridge_hent **hptr = &SLIST_FIRST(&priv->tab[bucket]);
 988
 989                 while (*hptr != NULL) {
 990                         struct ng_bridge_hent *const hent = *hptr;
 991
 992                         /* Make sure host's link really exists */
 993                         KASSERT(priv->links[hent->host.linkNum] != NULL,
 994                             ("%s: host %6D on nonexistent link %d\n",
 995                             __func__, hent->host.addr, ":",
 996                             hent->host.linkNum));
 997
 998                         /* Remove hosts we haven't heard from in a while */
 999                         if (++hent->host.staleness >= priv->conf.maxStaleness) {
1000                                 *hptr = SLIST_NEXT(hent, next);
1001                                 free(hent, M_NETGRAPH_BRIDGE);
1002                                 priv->numHosts--;
1003                         } else {
1004                                 if (hent->host.age < 0xffff)
1005                                         hent->host.age++;
1006                                 hptr = &SLIST_NEXT(hent, next);
1007                                 counter++;
1008                         }
1009                 }
1010         }
1011         KASSERT(priv->numHosts == counter,
1012             ("%s: hosts: %d != %d", __func__, priv->numHosts, counter));
1013
1014         /* Decrease table size if necessary */
1015         ng_bridge_rehash(priv);
1016
1017         /* Decrease loop counter on muted looped back links */
1018         for (counter = linkNum = 0; linkNum < NG_BRIDGE_MAX_LINKS; linkNum++) {
1019                 struct ng_bridge_link *const link = priv->links[linkNum];
1020
1021                 if (link != NULL) {
1022                         if (link->loopCount != 0) {
1023                                 link->loopCount--;
1024                                 if (link->loopCount == 0
1025                                     && priv->conf.debugLevel >= 2) {
1026                                         log(LOG_INFO, "ng_bridge: %s:"
1027                                             " restoring looped back link%d\n",
1028                                             ng_bridge_nodename(node), linkNum);
1029                                 }
1030                         }
1031                         counter++;
1032                 }
1033         }
1034         KASSERT(priv->numLinks == counter,
1035             ("%s: links: %d != %d", __func__, priv->numLinks, counter));
1036
1037         /* Register a new timeout, keeping the existing node reference */
1038         ng_callout(&priv->timer, node, NULL, hz, ng_bridge_timeout, NULL, 0);
1039 }
1040
1041 /*
1042  * Return node's "name", even if it doesn't have one.
1043  */
1044 static const char *
1045 ng_bridge_nodename(node_p node)
1046 {
1047         static char name[NG_NODESIZ];
1048
1049         if (NG_NODE_HAS_NAME(node))
1050                 snprintf(name, sizeof(name), "%s", NG_NODE_NAME(node));
1051         else
1052                 snprintf(name, sizeof(name), "[%x]", ng_node2ID(node));
1053         return name;
1054 }
1055