sys/netgraph7/bridge/ng_bridge.c

   1 /*
   2  * ng_bridge.c
   3  */
   4
   5 /*-
   6  * Copyright (c) 2000 Whistle Communications, Inc.
   7  * All rights reserved.
   8  *
   9  * Subject to the following obligations and disclaimer of warranty, use and
  10  * redistribution of this software, in source or object code forms, with or
  11  * without modifications are expressly permitted by Whistle Communications;
  12  * provided, however, that:
  13  * 1. Any and all reproductions of the source or object code must include the
  14  *    copyright notice above and the following disclaimer of warranties; and
  15  * 2. No rights are granted, in any manner or form, to use Whistle
  16  *    Communications, Inc. trademarks, including the mark "WHISTLE
  17  *    COMMUNICATIONS" on advertising, endorsements, or otherwise except as
  18  *    such appears in the above copyright notice or in the software.
  19  *
  20  * THIS SOFTWARE IS BEING PROVIDED BY WHISTLE COMMUNICATIONS "AS IS", AND
  21  * TO THE MAXIMUM EXTENT PERMITTED BY LAW, WHISTLE COMMUNICATIONS MAKES NO
  22  * REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED, REGARDING THIS SOFTWARE,
  23  * INCLUDING WITHOUT LIMITATION, ANY AND ALL IMPLIED WARRANTIES OF
  24  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT.
  25  * WHISTLE COMMUNICATIONS DOES NOT WARRANT, GUARANTEE, OR MAKE ANY
  26  * REPRESENTATIONS REGARDING THE USE OF, OR THE RESULTS OF THE USE OF THIS
  27  * SOFTWARE IN TERMS OF ITS CORRECTNESS, ACCURACY, RELIABILITY OR OTHERWISE.
  28  * IN NO EVENT SHALL WHISTLE COMMUNICATIONS BE LIABLE FOR ANY DAMAGES
  29  * RESULTING FROM OR ARISING OUT OF ANY USE OF THIS SOFTWARE, INCLUDING
  30  * WITHOUT LIMITATION, ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
  31  * PUNITIVE, OR CONSEQUENTIAL DAMAGES, PROCUREMENT OF SUBSTITUTE GOODS OR
  32  * SERVICES, LOSS OF USE, DATA OR PROFITS, HOWEVER CAUSED AND UNDER ANY
  33  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  34  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  35  * THIS SOFTWARE, EVEN IF WHISTLE COMMUNICATIONS IS ADVISED OF THE POSSIBILITY
  36  * OF SUCH DAMAGE.
  37  *
  38  * Author: Archie Cobbs <archie@freebsd.org>
  39  *
  40  * $FreeBSD: src/sys/netgraph/ng_bridge.c,v 1.31 2005/02/09 15:14:44 ru Exp $
  41  * $DragonFly: src/sys/netgraph7/ng_bridge.c,v 1.2 2008/06/26 23:05:35 dillon Exp $
  42  */
  43
  44 /*
  45  * ng_bridge(4) netgraph node type
  46  *
  47  * The node performs standard intelligent Ethernet bridging over
  48  * each of its connected hooks, or links.  A simple loop detection
  49  * algorithm is included which disables a link for priv->conf.loopTimeout
  50  * seconds when a host is seen to have jumped from one link to
  51  * another within priv->conf.minStableAge seconds.
  52  *
  53  * We keep a hashtable that maps Ethernet addresses to host info,
  54  * which is contained in struct ng_bridge_host's. These structures
  55  * tell us on which link the host may be found. A host's entry will
  56  * expire after priv->conf.maxStaleness seconds.
  57  *
  58  * This node is optimzed for stable networks, where machines jump
  59  * from one port to the other only rarely.
  60  */
  61
  62 #include <sys/param.h>
  63 #include <sys/systm.h>
  64 #include <sys/kernel.h>
  65 #include <sys/malloc.h>
  66 #include <sys/mbuf.h>
  67 #include <sys/errno.h>
  68 #include <sys/syslog.h>
  69 #include <sys/socket.h>
  70 #include <sys/ctype.h>
  71
  72 #include <net/if.h>
  73 #include <net/ethernet.h>
  74
  75 #include <netinet/in.h>
  76 #include <net/ipfw/ip_fw.h>
  77
  78 #include <netgraph7/ng_message.h>
  79 #include <netgraph7/netgraph.h>
  80 #include <netgraph7/ng_parse.h>
  81 #include "ng_bridge.h"
  82
  83 #ifdef NG_SEPARATE_MALLOC
  84 MALLOC_DEFINE(M_NETGRAPH_BRIDGE, "netgraph_bridge", "netgraph bridge node ");
  85 #else
  86 #define M_NETGRAPH_BRIDGE M_NETGRAPH
  87 #endif
  88
  89 /* Per-link private data */
  90 struct ng_bridge_link {
  91         hook_p                          hook;           /* netgraph hook */
  92         u_int16_t                       loopCount;      /* loop ignore timer */
  93         struct ng_bridge_link_stats     stats;          /* link stats */
  94 };
  95
  96 /* Per-node private data */
  97 struct ng_bridge_private {
  98         struct ng_bridge_bucket *tab;           /* hash table bucket array */
  99         struct ng_bridge_link   *links[NG_BRIDGE_MAX_LINKS];
 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         struct callout          timer;          /* one second periodic timer */
 107 };
 108 typedef struct ng_bridge_private *priv_p;
 109
 110 /* Information about a host, stored in a hash table entry */
 111 struct ng_bridge_hent {
 112         struct ng_bridge_host           host;   /* actual host info */
 113         SLIST_ENTRY(ng_bridge_hent)     next;   /* next entry in bucket */
 114 };
 115
 116 /* Hash table bucket declaration */
 117 SLIST_HEAD(ng_bridge_bucket, ng_bridge_hent);
 118
 119 /* Netgraph node methods */
 120 static ng_constructor_t ng_bridge_constructor;
 121 static ng_rcvmsg_t      ng_bridge_rcvmsg;
 122 static ng_shutdown_t    ng_bridge_shutdown;
 123 static ng_newhook_t     ng_bridge_newhook;
 124 static ng_rcvdata_t     ng_bridge_rcvdata;
 125 static ng_disconnect_t  ng_bridge_disconnect;
 126
 127 /* Other internal functions */
 128 static struct   ng_bridge_host *ng_bridge_get(priv_p priv, const u_char *addr);
 129 static int      ng_bridge_put(priv_p priv, const u_char *addr, int linkNum);
 130 static void     ng_bridge_rehash(priv_p priv);
 131 static void     ng_bridge_remove_hosts(priv_p priv, int linkNum);
 132 static void     ng_bridge_timeout(node_p node, hook_p hook, void *arg1, int arg2);
 133 static const    char *ng_bridge_nodename(node_p node);
 134
 135 /* Ethernet broadcast */
 136 static const u_char ng_bridge_bcast_addr[ETHER_ADDR_LEN] =
 137     { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
 138
 139 /* Store each hook's link number in the private field */
 140 #define LINK_NUM(hook)          (*(u_int16_t *)(&(hook)->private))
 141
 142 /* Compare Ethernet addresses using 32 and 16 bit words instead of bytewise */
 143 #define ETHER_EQUAL(a,b)        (((const u_int32_t *)(a))[0] \
 144                                         == ((const u_int32_t *)(b))[0] \
 145                                     && ((const u_int16_t *)(a))[2] \
 146                                         == ((const u_int16_t *)(b))[2])
 147
 148 /* Minimum and maximum number of hash buckets. Must be a power of two. */
 149 #define MIN_BUCKETS             (1 << 5)        /* 32 */
 150 #define MAX_BUCKETS             (1 << 14)       /* 16384 */
 151
 152 /* Configuration default values */
 153 #define DEFAULT_LOOP_TIMEOUT    60
 154 #define DEFAULT_MAX_STALENESS   (15 * 60)       /* same as ARP timeout */
 155 #define DEFAULT_MIN_STABLE_AGE  1
 156
 157 /******************************************************************
 158                     NETGRAPH PARSE TYPES
 159 ******************************************************************/
 160
 161 /*
 162  * How to determine the length of the table returned by NGM_BRIDGE_GET_TABLE
 163  */
 164 static int
 165 ng_bridge_getTableLength(const struct ng_parse_type *type,
 166         const u_char *start, const u_char *buf)
 167 {
 168         const struct ng_bridge_host_ary *const hary
 169             = (const struct ng_bridge_host_ary *)(buf - sizeof(u_int32_t));
 170
 171         return hary->numHosts;
 172 }
 173
 174 /* Parse type for struct ng_bridge_host_ary */
 175 static const struct ng_parse_struct_field ng_bridge_host_type_fields[]
 176         = NG_BRIDGE_HOST_TYPE_INFO(&ng_parse_enaddr_type);
 177 static const struct ng_parse_type ng_bridge_host_type = {
 178         &ng_parse_struct_type,
 179         &ng_bridge_host_type_fields
 180 };
 181 static const struct ng_parse_array_info ng_bridge_hary_type_info = {
 182         &ng_bridge_host_type,
 183         ng_bridge_getTableLength
 184 };
 185 static const struct ng_parse_type ng_bridge_hary_type = {
 186         &ng_parse_array_type,
 187         &ng_bridge_hary_type_info
 188 };
 189 static const struct ng_parse_struct_field ng_bridge_host_ary_type_fields[]
 190         = NG_BRIDGE_HOST_ARY_TYPE_INFO(&ng_bridge_hary_type);
 191 static const struct ng_parse_type ng_bridge_host_ary_type = {
 192         &ng_parse_struct_type,
 193         &ng_bridge_host_ary_type_fields
 194 };
 195
 196 /* Parse type for struct ng_bridge_config */
 197 static const struct ng_parse_fixedarray_info ng_bridge_ipfwary_type_info = {
 198         &ng_parse_uint8_type,
 199         NG_BRIDGE_MAX_LINKS
 200 };
 201 static const struct ng_parse_type ng_bridge_ipfwary_type = {
 202         &ng_parse_fixedarray_type,
 203         &ng_bridge_ipfwary_type_info
 204 };
 205 static const struct ng_parse_struct_field ng_bridge_config_type_fields[]
 206         = NG_BRIDGE_CONFIG_TYPE_INFO(&ng_bridge_ipfwary_type);
 207 static const struct ng_parse_type ng_bridge_config_type = {
 208         &ng_parse_struct_type,
 209         &ng_bridge_config_type_fields
 210 };
 211
 212 /* Parse type for struct ng_bridge_link_stat */
 213 static const struct ng_parse_struct_field ng_bridge_stats_type_fields[]
 214         = NG_BRIDGE_STATS_TYPE_INFO;
 215 static const struct ng_parse_type ng_bridge_stats_type = {
 216         &ng_parse_struct_type,
 217         &ng_bridge_stats_type_fields
 218 };
 219
 220 /* List of commands and how to convert arguments to/from ASCII */
 221 static const struct ng_cmdlist ng_bridge_cmdlist[] = {
 222         {
 223           NGM_BRIDGE_COOKIE,
 224           NGM_BRIDGE_SET_CONFIG,
 225           "setconfig",
 226           &ng_bridge_config_type,
 227           NULL
 228         },
 229         {
 230           NGM_BRIDGE_COOKIE,
 231           NGM_BRIDGE_GET_CONFIG,
 232           "getconfig",
 233           NULL,
 234           &ng_bridge_config_type
 235         },
 236         {
 237           NGM_BRIDGE_COOKIE,
 238           NGM_BRIDGE_RESET,
 239           "reset",
 240           NULL,
 241           NULL
 242         },
 243         {
 244           NGM_BRIDGE_COOKIE,
 245           NGM_BRIDGE_GET_STATS,
 246           "getstats",
 247           &ng_parse_uint32_type,
 248           &ng_bridge_stats_type
 249         },
 250         {
 251           NGM_BRIDGE_COOKIE,
 252           NGM_BRIDGE_CLR_STATS,
 253           "clrstats",
 254           &ng_parse_uint32_type,
 255           NULL
 256         },
 257         {
 258           NGM_BRIDGE_COOKIE,
 259           NGM_BRIDGE_GETCLR_STATS,
 260           "getclrstats",
 261           &ng_parse_uint32_type,
 262           &ng_bridge_stats_type
 263         },
 264         {
 265           NGM_BRIDGE_COOKIE,
 266           NGM_BRIDGE_GET_TABLE,
 267           "gettable",
 268           NULL,
 269           &ng_bridge_host_ary_type
 270         },
 271         { 0 }
 272 };
 273
 274 /* Node type descriptor */
 275 static struct ng_type ng_bridge_typestruct = {
 276         .version =      NG_ABI_VERSION,
 277         .name =         NG_BRIDGE_NODE_TYPE,
 278         .constructor =  ng_bridge_constructor,
 279         .rcvmsg =       ng_bridge_rcvmsg,
 280         .shutdown =     ng_bridge_shutdown,
 281         .newhook =      ng_bridge_newhook,
 282         .rcvdata =      ng_bridge_rcvdata,
 283         .disconnect =   ng_bridge_disconnect,
 284         .cmdlist =      ng_bridge_cmdlist,
 285 };
 286 NETGRAPH_INIT(bridge, &ng_bridge_typestruct);
 287
 288 /******************************************************************
 289                     NETGRAPH NODE METHODS
 290 ******************************************************************/
 291
 292 /*
 293  * Node constructor
 294  */
 295 static int
 296 ng_bridge_constructor(node_p node)
 297 {
 298         priv_p priv;
 299
 300         /* Allocate and initialize private info */
 301         priv = kmalloc(sizeof(*priv), M_NETGRAPH_BRIDGE,
 302                        M_WAITOK | M_NULLOK | M_ZERO);
 303         if (priv == NULL)
 304                 return (ENOMEM);
 305         ng_callout_init(&priv->timer);
 306
 307         /* Allocate and initialize hash table, etc. */
 308         priv->tab = kmalloc(MIN_BUCKETS * sizeof(*priv->tab),
 309                             M_NETGRAPH_BRIDGE, M_WAITOK | M_NULLOK | M_ZERO);
 310         if (priv->tab == NULL) {
 311                 kfree(priv, M_NETGRAPH_BRIDGE);
 312                 return (ENOMEM);
 313         }
 314         priv->numBuckets = MIN_BUCKETS;
 315         priv->hashMask = MIN_BUCKETS - 1;
 316         priv->conf.debugLevel = 1;
 317         priv->conf.loopTimeout = DEFAULT_LOOP_TIMEOUT;
 318         priv->conf.maxStaleness = DEFAULT_MAX_STALENESS;
 319         priv->conf.minStableAge = DEFAULT_MIN_STABLE_AGE;
 320
 321         /*
 322          * This node has all kinds of stuff that could be screwed by SMP.
 323          * Until it gets it's own internal protection, we go through in
 324          * single file. This could hurt a machine bridging beteen two
 325          * GB ethernets so it should be fixed.
 326          * When it's fixed the process SHOULD NOT SLEEP, spinlocks please!
 327          * (and atomic ops )
 328          */
 329         NG_NODE_FORCE_WRITER(node);
 330         NG_NODE_SET_PRIVATE(node, priv);
 331         priv->node = node;
 332
 333         /* Start timer; timer is always running while node is alive */
 334         ng_callout(&priv->timer, node, NULL, hz, ng_bridge_timeout, NULL, 0);
 335
 336         /* Done */
 337         return (0);
 338 }
 339
 340 /*
 341  * Method for attaching a new hook
 342  */
 343 static  int
 344 ng_bridge_newhook(node_p node, hook_p hook, const char *name)
 345 {
 346         const priv_p priv = NG_NODE_PRIVATE(node);
 347
 348         /* Check for a link hook */
 349         if (strncmp(name, NG_BRIDGE_HOOK_LINK_PREFIX,
 350             strlen(NG_BRIDGE_HOOK_LINK_PREFIX)) == 0) {
 351                 const char *cp;
 352                 char *eptr;
 353                 u_long linkNum;
 354
 355                 cp = name + strlen(NG_BRIDGE_HOOK_LINK_PREFIX);
 356                 if (!isdigit(*cp) || (cp[0] == '0' && cp[1] != '\0'))
 357                         return (EINVAL);
 358                 linkNum = strtoul(cp, &eptr, 10);
 359                 if (*eptr != '\0' || linkNum >= NG_BRIDGE_MAX_LINKS)
 360                         return (EINVAL);
 361                 if (priv->links[linkNum] != NULL)
 362                         return (EISCONN);
 363                 priv->links[linkNum] = kmalloc(sizeof(*priv->links[linkNum]),
 364                                                M_NETGRAPH_BRIDGE,
 365                                                M_WAITOK | M_NULLOK | M_ZERO);
 366                 if (priv->links[linkNum] == NULL)
 367                         return (ENOMEM);
 368                 priv->links[linkNum]->hook = hook;
 369                 NG_HOOK_SET_PRIVATE(hook, (void *)linkNum);
 370                 priv->numLinks++;
 371                 return (0);
 372         }
 373
 374         /* Unknown hook name */
 375         return (EINVAL);
 376 }
 377
 378 /*
 379  * Receive a control message
 380  */
 381 static int
 382 ng_bridge_rcvmsg(node_p node, item_p item, hook_p lasthook)
 383 {
 384         const priv_p priv = NG_NODE_PRIVATE(node);
 385         struct ng_mesg *resp = NULL;
 386         int error = 0;
 387         struct ng_mesg *msg;
 388
 389         NGI_GET_MSG(item, msg);
 390         switch (msg->header.typecookie) {
 391         case NGM_BRIDGE_COOKIE:
 392                 switch (msg->header.cmd) {
 393                 case NGM_BRIDGE_GET_CONFIG:
 394                     {
 395                         struct ng_bridge_config *conf;
 396
 397                         NG_MKRESPONSE(resp, msg,
 398                             sizeof(struct ng_bridge_config), M_WAITOK | M_NULLOK);
 399                         if (resp == NULL) {
 400                                 error = ENOMEM;
 401                                 break;
 402                         }
 403                         conf = (struct ng_bridge_config *)resp->data;
 404                         *conf = priv->conf;     /* no sanity checking needed */
 405                         break;
 406                     }
 407                 case NGM_BRIDGE_SET_CONFIG:
 408                     {
 409                         struct ng_bridge_config *conf;
 410                         int i;
 411
 412                         if (msg->header.arglen
 413                             != sizeof(struct ng_bridge_config)) {
 414                                 error = EINVAL;
 415                                 break;
 416                         }
 417                         conf = (struct ng_bridge_config *)msg->data;
 418                         priv->conf = *conf;
 419                         for (i = 0; i < NG_BRIDGE_MAX_LINKS; i++)
 420                                 priv->conf.ipfw[i] = !!priv->conf.ipfw[i];
 421                         break;
 422                     }
 423                 case NGM_BRIDGE_RESET:
 424                     {
 425                         int i;
 426
 427                         /* Flush all entries in the hash table */
 428                         ng_bridge_remove_hosts(priv, -1);
 429
 430                         /* Reset all loop detection counters and stats */
 431                         for (i = 0; i < NG_BRIDGE_MAX_LINKS; i++) {
 432                                 if (priv->links[i] == NULL)
 433                                         continue;
 434                                 priv->links[i]->loopCount = 0;
 435                                 bzero(&priv->links[i]->stats,
 436                                     sizeof(priv->links[i]->stats));
 437                         }
 438                         break;
 439                     }
 440                 case NGM_BRIDGE_GET_STATS:
 441                 case NGM_BRIDGE_CLR_STATS:
 442                 case NGM_BRIDGE_GETCLR_STATS:
 443                     {
 444                         struct ng_bridge_link *link;
 445                         int linkNum;
 446
 447                         /* Get link number */
 448                         if (msg->header.arglen != sizeof(u_int32_t)) {
 449                                 error = EINVAL;
 450                                 break;
 451                         }
 452                         linkNum = *((u_int32_t *)msg->data);
 453                         if (linkNum < 0 || linkNum >= NG_BRIDGE_MAX_LINKS) {
 454                                 error = EINVAL;
 455                                 break;
 456                         }
 457                         if ((link = priv->links[linkNum]) == NULL) {
 458                                 error = ENOTCONN;
 459                                 break;
 460                         }
 461
 462                         /* Get/clear stats */
 463                         if (msg->header.cmd != NGM_BRIDGE_CLR_STATS) {
 464                                 NG_MKRESPONSE(resp, msg,
 465                                     sizeof(link->stats), M_WAITOK | M_NULLOK);
 466                                 if (resp == NULL) {
 467                                         error = ENOMEM;
 468                                         break;
 469                                 }
 470                                 bcopy(&link->stats,
 471                                     resp->data, sizeof(link->stats));
 472                         }
 473                         if (msg->header.cmd != NGM_BRIDGE_GET_STATS)
 474                                 bzero(&link->stats, sizeof(link->stats));
 475                         break;
 476                     }
 477                 case NGM_BRIDGE_GET_TABLE:
 478                     {
 479                         struct ng_bridge_host_ary *ary;
 480                         struct ng_bridge_hent *hent;
 481                         int i = 0, bucket;
 482
 483                         NG_MKRESPONSE(resp, msg, sizeof(*ary)
 484                             + (priv->numHosts * sizeof(*ary->hosts)), M_WAITOK | M_NULLOK);
 485                         if (resp == NULL) {
 486                                 error = ENOMEM;
 487                                 break;
 488                         }
 489                         ary = (struct ng_bridge_host_ary *)resp->data;
 490                         ary->numHosts = priv->numHosts;
 491                         for (bucket = 0; bucket < priv->numBuckets; bucket++) {
 492                                 SLIST_FOREACH(hent, &priv->tab[bucket], next)
 493                                         ary->hosts[i++] = hent->host;
 494                         }
 495                         break;
 496                     }
 497                 default:
 498                         error = EINVAL;
 499                         break;
 500                 }
 501                 break;
 502         default:
 503                 error = EINVAL;
 504                 break;
 505         }
 506
 507         /* Done */
 508         NG_RESPOND_MSG(error, node, item, resp);
 509         NG_FREE_MSG(msg);
 510         return (error);
 511 }
 512
 513 /*
 514  * Receive data on a hook
 515  */
 516 static int
 517 ng_bridge_rcvdata(hook_p hook, item_p item)
 518 {
 519         const node_p node = NG_HOOK_NODE(hook);
 520         const priv_p priv = NG_NODE_PRIVATE(node);
 521         struct ng_bridge_host *host;
 522         struct ng_bridge_link *link;
 523         struct ether_header *eh;
 524         int error = 0, linkNum, linksSeen;
 525         int manycast;
 526         struct mbuf *m;
 527         struct ng_bridge_link *firstLink;
 528
 529         NGI_GET_M(item, m);
 530         /* Get link number */
 531         linkNum = (intptr_t)NG_HOOK_PRIVATE(hook);
 532         KASSERT(linkNum >= 0 && linkNum < NG_BRIDGE_MAX_LINKS,
 533             ("%s: linkNum=%u", __func__, linkNum));
 534         link = priv->links[linkNum];
 535         KASSERT(link != NULL, ("%s: link%d null", __func__, linkNum));
 536
 537         /* Sanity check packet and pull up header */
 538         if (m->m_pkthdr.len < ETHER_HDR_LEN) {
 539                 link->stats.recvRunts++;
 540                 NG_FREE_ITEM(item);
 541                 NG_FREE_M(m);
 542                 return (EINVAL);
 543         }
 544         if (m->m_len < ETHER_HDR_LEN && !(m = m_pullup(m, ETHER_HDR_LEN))) {
 545                 link->stats.memoryFailures++;
 546                 NG_FREE_ITEM(item);
 547                 return (ENOBUFS);
 548         }
 549         eh = mtod(m, struct ether_header *);
 550         if ((eh->ether_shost[0] & 1) != 0) {
 551                 link->stats.recvInvalid++;
 552                 NG_FREE_ITEM(item);
 553                 NG_FREE_M(m);
 554                 return (EINVAL);
 555         }
 556
 557         /* Is link disabled due to a loopback condition? */
 558         if (link->loopCount != 0) {
 559                 link->stats.loopDrops++;
 560                 NG_FREE_ITEM(item);
 561                 NG_FREE_M(m);
 562                 return (ELOOP);         /* XXX is this an appropriate error? */
 563         }
 564
 565         /* Update stats */
 566         link->stats.recvPackets++;
 567         link->stats.recvOctets += m->m_pkthdr.len;
 568         if ((manycast = (eh->ether_dhost[0] & 1)) != 0) {
 569                 if (ETHER_EQUAL(eh->ether_dhost, ng_bridge_bcast_addr)) {
 570                         link->stats.recvBroadcasts++;
 571                         manycast = 2;
 572                 } else
 573                         link->stats.recvMulticasts++;
 574         }
 575
 576         /* Look up packet's source Ethernet address in hashtable */
 577         if ((host = ng_bridge_get(priv, eh->ether_shost)) != NULL) {
 578
 579                 /* Update time since last heard from this host */
 580                 host->staleness = 0;
 581
 582                 /* Did host jump to a different link? */
 583                 if (host->linkNum != linkNum) {
 584
 585                         /*
 586                          * If the host's old link was recently established
 587                          * on the old link and it's already jumped to a new
 588                          * link, declare a loopback condition.
 589                          */
 590                         if (host->age < priv->conf.minStableAge) {
 591
 592                                 /* Log the problem */
 593                                 if (priv->conf.debugLevel >= 2) {
 594                                         struct ifnet *ifp = m->m_pkthdr.rcvif;
 595                                         char suffix[32];
 596
 597                                         if (ifp != NULL)
 598                                                 snprintf(suffix, sizeof(suffix),
 599                                                     " (%s)", ifp->if_xname);
 600                                         else
 601                                                 *suffix = '\0';
 602                                         log(LOG_WARNING, "ng_bridge: %s:"
 603                                             " loopback detected on %s%s\n",
 604                                             ng_bridge_nodename(node),
 605                                             NG_HOOK_NAME(hook), suffix);
 606                                 }
 607
 608                                 /* Mark link as linka non grata */
 609                                 link->loopCount = priv->conf.loopTimeout;
 610                                 link->stats.loopDetects++;
 611
 612                                 /* Forget all hosts on this link */
 613                                 ng_bridge_remove_hosts(priv, linkNum);
 614
 615                                 /* Drop packet */
 616                                 link->stats.loopDrops++;
 617                                 NG_FREE_ITEM(item);
 618                                 NG_FREE_M(m);
 619                                 return (ELOOP);         /* XXX appropriate? */
 620                         }
 621
 622                         /* Move host over to new link */
 623                         host->linkNum = linkNum;
 624                         host->age = 0;
 625                 }
 626         } else {
 627                 if (!ng_bridge_put(priv, eh->ether_shost, linkNum)) {
 628                         link->stats.memoryFailures++;
 629                         NG_FREE_ITEM(item);
 630                         NG_FREE_M(m);
 631                         return (ENOMEM);
 632                 }
 633         }
 634
 635         /* Run packet through ipfw processing, if enabled */
 636 #if 0
 637         if (priv->conf.ipfw[linkNum] && fw_enable && ip_fw_chk_ptr != NULL) {
 638                 /* XXX not implemented yet */
 639         }
 640 #endif
 641
 642         /*
 643          * If unicast and destination host known, deliver to host's link,
 644          * unless it is the same link as the packet came in on.
 645          */
 646         if (!manycast) {
 647
 648                 /* Determine packet destination link */
 649                 if ((host = ng_bridge_get(priv, eh->ether_dhost)) != NULL) {
 650                         struct ng_bridge_link *const destLink
 651                             = priv->links[host->linkNum];
 652
 653                         /* If destination same as incoming link, do nothing */
 654                         KASSERT(destLink != NULL,
 655                             ("%s: link%d null", __func__, host->linkNum));
 656                         if (destLink == link) {
 657                                 NG_FREE_ITEM(item);
 658                                 NG_FREE_M(m);
 659                                 return (0);
 660                         }
 661
 662                         /* Deliver packet out the destination link */
 663                         destLink->stats.xmitPackets++;
 664                         destLink->stats.xmitOctets += m->m_pkthdr.len;
 665                         NG_FWD_NEW_DATA(error, item, destLink->hook, m);
 666                         return (error);
 667                 }
 668
 669                 /* Destination host is not known */
 670                 link->stats.recvUnknown++;
 671         }
 672
 673         /* Distribute unknown, multicast, broadcast pkts to all other links */
 674         firstLink = NULL;
 675         for (linkNum = linksSeen = 0; linksSeen <= priv->numLinks; linkNum++) {
 676                 struct ng_bridge_link *destLink;
 677                 struct mbuf *m2 = NULL;
 678
 679                 /*
 680                  * If we have checked all the links then now
 681                  * send the original on its reserved link
 682                  */
 683                 if (linksSeen == priv->numLinks) {
 684                         /* If we never saw a good link, leave. */
 685                         if (firstLink == NULL) {
 686                                 NG_FREE_ITEM(item);
 687                                 NG_FREE_M(m);
 688                                 return (0);
 689                         }
 690                         destLink = firstLink;
 691                 } else {
 692                         destLink = priv->links[linkNum];
 693                         if (destLink != NULL)
 694                                 linksSeen++;
 695                         /* Skip incoming link and disconnected links */
 696                         if (destLink == NULL || destLink == link) {
 697                                 continue;
 698                         }
 699                         if (firstLink == NULL) {
 700                                 /*
 701                                  * This is the first usable link we have found.
 702                                  * Reserve it for the originals.
 703                                  * If we never find another we save a copy.
 704                                  */
 705                                 firstLink = destLink;
 706                                 continue;
 707                         }
 708
 709                         /*
 710                          * It's usable link but not the reserved (first) one.
 711                          * Copy mbuf info for sending.
 712                          */
 713                         m2 = m_dup(m, MB_DONTWAIT);     /* XXX m_copypacket() */
 714                         if (m2 == NULL) {
 715                                 link->stats.memoryFailures++;
 716                                 NG_FREE_ITEM(item);
 717                                 NG_FREE_M(m);
 718                                 return (ENOBUFS);
 719                         }
 720                 }
 721
 722                 /* Update stats */
 723                 destLink->stats.xmitPackets++;
 724                 destLink->stats.xmitOctets += m->m_pkthdr.len;
 725                 switch (manycast) {
 726                 case 0:                                 /* unicast */
 727                         break;
 728                 case 1:                                 /* multicast */
 729                         destLink->stats.xmitMulticasts++;
 730                         break;
 731                 case 2:                                 /* broadcast */
 732                         destLink->stats.xmitBroadcasts++;
 733                         break;
 734                 }
 735
 736                 /* Send packet */
 737                 if (destLink == firstLink) {
 738                         /*
 739                          * If we've sent all the others, send the original
 740                          * on the first link we found.
 741                          */
 742                         NG_FWD_NEW_DATA(error, item, destLink->hook, m);
 743                         break; /* always done last - not really needed. */
 744                 } else {
 745                         NG_SEND_DATA_ONLY(error, destLink->hook, m2);
 746                 }
 747         }
 748         return (error);
 749 }
 750
 751 /*
 752  * Shutdown node
 753  */
 754 static int
 755 ng_bridge_shutdown(node_p node)
 756 {
 757         const priv_p priv = NG_NODE_PRIVATE(node);
 758
 759         /*
 760          * Shut down everything including the timer.  Even if the
 761          * callout has already been dequeued and is about to be
 762          * run, ng_bridge_timeout() won't be fired as the node
 763          * is already marked NGF_INVALID, so we're safe to free
 764          * the node now.
 765          */
 766         KASSERT(priv->numLinks == 0 && priv->numHosts == 0,
 767             ("%s: numLinks=%d numHosts=%d",
 768             __func__, priv->numLinks, priv->numHosts));
 769         ng_uncallout(&priv->timer, node);
 770         NG_NODE_SET_PRIVATE(node, NULL);
 771         NG_NODE_UNREF(node);
 772         kfree(priv->tab, M_NETGRAPH_BRIDGE);
 773         kfree(priv, M_NETGRAPH_BRIDGE);
 774         return (0);
 775 }
 776
 777 /*
 778  * Hook disconnection.
 779  */
 780 static int
 781 ng_bridge_disconnect(hook_p hook)
 782 {
 783         const priv_p priv = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
 784         int linkNum;
 785
 786         /* Get link number */
 787         linkNum = (intptr_t)NG_HOOK_PRIVATE(hook);
 788         KASSERT(linkNum >= 0 && linkNum < NG_BRIDGE_MAX_LINKS,
 789             ("%s: linkNum=%u", __func__, linkNum));
 790
 791         /* Remove all hosts associated with this link */
 792         ng_bridge_remove_hosts(priv, linkNum);
 793
 794         /* Free associated link information */
 795         KASSERT(priv->links[linkNum] != NULL, ("%s: no link", __func__));
 796         kfree(priv->links[linkNum], M_NETGRAPH_BRIDGE);
 797         priv->links[linkNum] = NULL;
 798         priv->numLinks--;
 799
 800         /* If no more hooks, go away */
 801         if ((NG_NODE_NUMHOOKS(NG_HOOK_NODE(hook)) == 0)
 802         && (NG_NODE_IS_VALID(NG_HOOK_NODE(hook)))) {
 803                 ng_rmnode_self(NG_HOOK_NODE(hook));
 804         }
 805         return (0);
 806 }
 807
 808 /******************************************************************
 809                     HASH TABLE FUNCTIONS
 810 ******************************************************************/
 811
 812 /*
 813  * Hash algorithm
 814  */
 815 #define HASH(addr,mask)         ( (((const u_int16_t *)(addr))[0]       \
 816                                  ^ ((const u_int16_t *)(addr))[1]       \
 817                                  ^ ((const u_int16_t *)(addr))[2]) & (mask) )
 818
 819 /*
 820  * Find a host entry in the table.
 821  */
 822 static struct ng_bridge_host *
 823 ng_bridge_get(priv_p priv, const u_char *addr)
 824 {
 825         const int bucket = HASH(addr, priv->hashMask);
 826         struct ng_bridge_hent *hent;
 827
 828         SLIST_FOREACH(hent, &priv->tab[bucket], next) {
 829                 if (ETHER_EQUAL(hent->host.addr, addr))
 830                         return (&hent->host);
 831         }
 832         return (NULL);
 833 }
 834
 835 /*
 836  * Add a new host entry to the table. This assumes the host doesn't
 837  * already exist in the table. Returns 1 on success, 0 if there
 838  * was a memory allocation failure.
 839  */
 840 static int
 841 ng_bridge_put(priv_p priv, const u_char *addr, int linkNum)
 842 {
 843         const int bucket = HASH(addr, priv->hashMask);
 844         struct ng_bridge_hent *hent;
 845
 846 #ifdef INVARIANTS
 847         /* Assert that entry does not already exist in hashtable */
 848         SLIST_FOREACH(hent, &priv->tab[bucket], next) {
 849                 KASSERT(!ETHER_EQUAL(hent->host.addr, addr),
 850                     ("%s: entry %6D exists in table", __func__, addr, ":"));
 851         }
 852 #endif
 853
 854         /* Allocate and initialize new hashtable entry */
 855         hent = kmalloc(sizeof(*hent), M_NETGRAPH_BRIDGE, M_WAITOK | M_NULLOK);
 856         if (hent == NULL)
 857                 return (0);
 858         bcopy(addr, hent->host.addr, ETHER_ADDR_LEN);
 859         hent->host.linkNum = linkNum;
 860         hent->host.staleness = 0;
 861         hent->host.age = 0;
 862
 863         /* Add new element to hash bucket */
 864         SLIST_INSERT_HEAD(&priv->tab[bucket], hent, next);
 865         priv->numHosts++;
 866
 867         /* Resize table if necessary */
 868         ng_bridge_rehash(priv);
 869         return (1);
 870 }
 871
 872 /*
 873  * Resize the hash table. We try to maintain the number of buckets
 874  * such that the load factor is in the range 0.25 to 1.0.
 875  *
 876  * If we can't get the new memory then we silently fail. This is OK
 877  * because things will still work and we'll try again soon anyway.
 878  */
 879 static void
 880 ng_bridge_rehash(priv_p priv)
 881 {
 882         struct ng_bridge_bucket *newTab;
 883         int oldBucket, newBucket;
 884         int newNumBuckets;
 885         u_int newMask;
 886
 887         /* Is table too full or too empty? */
 888         if (priv->numHosts > priv->numBuckets
 889             && (priv->numBuckets << 1) <= MAX_BUCKETS)
 890                 newNumBuckets = priv->numBuckets << 1;
 891         else if (priv->numHosts < (priv->numBuckets >> 2)
 892             && (priv->numBuckets >> 2) >= MIN_BUCKETS)
 893                 newNumBuckets = priv->numBuckets >> 2;
 894         else
 895                 return;
 896         newMask = newNumBuckets - 1;
 897
 898         /* Allocate and initialize new table */
 899         newTab = kmalloc(newNumBuckets * sizeof(*newTab), M_NETGRAPH_BRIDGE,
 900                          M_NOWAIT | M_ZERO);
 901         if (newTab == NULL)
 902                 return;
 903
 904         /* Move all entries from old table to new table */
 905         for (oldBucket = 0; oldBucket < priv->numBuckets; oldBucket++) {
 906                 struct ng_bridge_bucket *const oldList = &priv->tab[oldBucket];
 907
 908                 while (!SLIST_EMPTY(oldList)) {
 909                         struct ng_bridge_hent *const hent
 910                             = SLIST_FIRST(oldList);
 911
 912                         SLIST_REMOVE_HEAD(oldList, next);
 913                         newBucket = HASH(hent->host.addr, newMask);
 914                         SLIST_INSERT_HEAD(&newTab[newBucket], hent, next);
 915                 }
 916         }
 917
 918         /* Replace old table with new one */
 919         if (priv->conf.debugLevel >= 3) {
 920                 log(LOG_INFO, "ng_bridge: %s: table size %d -> %d\n",
 921                     ng_bridge_nodename(priv->node),
 922                     priv->numBuckets, newNumBuckets);
 923         }
 924         kfree(priv->tab, M_NETGRAPH_BRIDGE);
 925         priv->numBuckets = newNumBuckets;
 926         priv->hashMask = newMask;
 927         priv->tab = newTab;
 928         return;
 929 }
 930
 931 /******************************************************************
 932                     MISC FUNCTIONS
 933 ******************************************************************/
 934
 935 /*
 936  * Remove all hosts associated with a specific link from the hashtable.
 937  * If linkNum == -1, then remove all hosts in the table.
 938  */
 939 static void
 940 ng_bridge_remove_hosts(priv_p priv, int linkNum)
 941 {
 942         int bucket;
 943
 944         for (bucket = 0; bucket < priv->numBuckets; bucket++) {
 945                 struct ng_bridge_hent **hptr = &SLIST_FIRST(&priv->tab[bucket]);
 946
 947                 while (*hptr != NULL) {
 948                         struct ng_bridge_hent *const hent = *hptr;
 949
 950                         if (linkNum == -1 || hent->host.linkNum == linkNum) {
 951                                 *hptr = SLIST_NEXT(hent, next);
 952                                 kfree(hent, M_NETGRAPH_BRIDGE);
 953                                 priv->numHosts--;
 954                         } else
 955                                 hptr = &SLIST_NEXT(hent, next);
 956                 }
 957         }
 958 }
 959
 960 /*
 961  * Handle our once-per-second timeout event. We do two things:
 962  * we decrement link->loopCount for those links being muted due to
 963  * a detected loopback condition, and we remove any hosts from
 964  * the hashtable whom we haven't heard from in a long while.
 965  */
 966 static void
 967 ng_bridge_timeout(node_p node, hook_p hook, void *arg1, int arg2)
 968 {
 969         const priv_p priv = NG_NODE_PRIVATE(node);
 970         int bucket;
 971         int counter = 0;
 972         int linkNum;
 973
 974         /* Update host time counters and remove stale entries */
 975         for (bucket = 0; bucket < priv->numBuckets; bucket++) {
 976                 struct ng_bridge_hent **hptr = &SLIST_FIRST(&priv->tab[bucket]);
 977
 978                 while (*hptr != NULL) {
 979                         struct ng_bridge_hent *const hent = *hptr;
 980
 981                         /* Make sure host's link really exists */
 982                         KASSERT(priv->links[hent->host.linkNum] != NULL,
 983                             ("%s: host %6D on nonexistent link %d\n",
 984                             __func__, hent->host.addr, ":",
 985                             hent->host.linkNum));
 986
 987                         /* Remove hosts we haven't heard from in a while */
 988                         if (++hent->host.staleness >= priv->conf.maxStaleness) {
 989                                 *hptr = SLIST_NEXT(hent, next);
 990                                 kfree(hent, M_NETGRAPH_BRIDGE);
 991                                 priv->numHosts--;
 992                         } else {
 993                                 if (hent->host.age < 0xffff)
 994                                         hent->host.age++;
 995                                 hptr = &SLIST_NEXT(hent, next);
 996                                 counter++;
 997                         }
 998                 }
 999         }
1000         KASSERT(priv->numHosts == counter,
1001             ("%s: hosts: %d != %d", __func__, priv->numHosts, counter));
1002
1003         /* Decrease table size if necessary */
1004         ng_bridge_rehash(priv);
1005
1006         /* Decrease loop counter on muted looped back links */
1007         for (counter = linkNum = 0; linkNum < NG_BRIDGE_MAX_LINKS; linkNum++) {
1008                 struct ng_bridge_link *const link = priv->links[linkNum];
1009
1010                 if (link != NULL) {
1011                         if (link->loopCount != 0) {
1012                                 link->loopCount--;
1013                                 if (link->loopCount == 0
1014                                     && priv->conf.debugLevel >= 2) {
1015                                         log(LOG_INFO, "ng_bridge: %s:"
1016                                             " restoring looped back link%d\n",
1017                                             ng_bridge_nodename(node), linkNum);
1018                                 }
1019                         }
1020                         counter++;
1021                 }
1022         }
1023         KASSERT(priv->numLinks == counter,
1024             ("%s: links: %d != %d", __func__, priv->numLinks, counter));
1025
1026         /* Register a new timeout, keeping the existing node reference */
1027         ng_callout(&priv->timer, node, NULL, hz, ng_bridge_timeout, NULL, 0);
1028 }
1029
1030 /*
1031  * Return node's "name", even if it doesn't have one.
1032  */
1033 static const char *
1034 ng_bridge_nodename(node_p node)
1035 {
1036         static char name[NG_NODESIZ];
1037
1038         if (NG_NODE_NAME(node) != NULL)
1039                 snprintf(name, sizeof(name), "%s", NG_NODE_NAME(node));
1040         else
1041                 snprintf(name, sizeof(name), "[%x]", ng_node2ID(node));
1042         return name;
1043 }
1044