sys/netgraph/bridge/ng_bridge.c

   1
   2 /*
   3  * ng_bridge.c
   4  *
   5  * Copyright (c) 2000 Whistle Communications, Inc.
   6  * All rights reserved.
   7  *
   8  * Subject to the following obligations and disclaimer of warranty, use and
   9  * redistribution of this software, in source or object code forms, with or
  10  * without modifications are expressly permitted by Whistle Communications;
  11  * provided, however, that:
  12  * 1. Any and all reproductions of the source or object code must include the
  13  *    copyright notice above and the following disclaimer of warranties; and
  14  * 2. No rights are granted, in any manner or form, to use Whistle
  15  *    Communications, Inc. trademarks, including the mark "WHISTLE
  16  *    COMMUNICATIONS" on advertising, endorsements, or otherwise except as
  17  *    such appears in the above copyright notice or in the software.
  18  *
  19  * THIS SOFTWARE IS BEING PROVIDED BY WHISTLE COMMUNICATIONS "AS IS", AND
  20  * TO THE MAXIMUM EXTENT PERMITTED BY LAW, WHISTLE COMMUNICATIONS MAKES NO
  21  * REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED, REGARDING THIS SOFTWARE,
  22  * INCLUDING WITHOUT LIMITATION, ANY AND ALL IMPLIED WARRANTIES OF
  23  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT.
  24  * WHISTLE COMMUNICATIONS DOES NOT WARRANT, GUARANTEE, OR MAKE ANY
  25  * REPRESENTATIONS REGARDING THE USE OF, OR THE RESULTS OF THE USE OF THIS
  26  * SOFTWARE IN TERMS OF ITS CORRECTNESS, ACCURACY, RELIABILITY OR OTHERWISE.
  27  * IN NO EVENT SHALL WHISTLE COMMUNICATIONS BE LIABLE FOR ANY DAMAGES
  28  * RESULTING FROM OR ARISING OUT OF ANY USE OF THIS SOFTWARE, INCLUDING
  29  * WITHOUT LIMITATION, ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
  30  * PUNITIVE, OR CONSEQUENTIAL DAMAGES, PROCUREMENT OF SUBSTITUTE GOODS OR
  31  * SERVICES, LOSS OF USE, DATA OR PROFITS, HOWEVER CAUSED AND UNDER ANY
  32  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  33  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  34  * THIS SOFTWARE, EVEN IF WHISTLE COMMUNICATIONS IS ADVISED OF THE POSSIBILITY
  35  * OF SUCH DAMAGE.
  36  *
  37  * Author: Archie Cobbs <archie@freebsd.org>
  38  *
  39  * $FreeBSD: src/sys/netgraph/ng_bridge.c,v 1.1.2.5 2002/07/02 23:44:02 archie Exp $
  40  */
  41
  42 /*
  43  * ng_bridge(4) netgraph node type
  44  *
  45  * The node performs standard intelligent Ethernet bridging over
  46  * each of its connected hooks, or links.  A simple loop detection
  47  * algorithm is included which disables a link for priv->conf.loopTimeout
  48  * seconds when a host is seen to have jumped from one link to
  49  * another within priv->conf.minStableAge seconds.
  50  *
  51  * We keep a hashtable that maps Ethernet addresses to host info,
  52  * which is contained in struct ng_bridge_host's. These structures
  53  * tell us on which link the host may be found. A host's entry will
  54  * expire after priv->conf.maxStaleness seconds.
  55  *
  56  * This node is optimzed for stable networks, where machines jump
  57  * from one port to the other only rarely.
  58  */
  59
  60 #include <sys/param.h>
  61 #include <sys/systm.h>
  62 #include <sys/kernel.h>
  63 #include <sys/malloc.h>
  64 #include <sys/mbuf.h>
  65 #include <sys/errno.h>
  66 #include <sys/syslog.h>
  67 #include <sys/socket.h>
  68 #include <sys/ctype.h>
  69 #include <sys/thread2.h>
  70
  71 #include <net/if.h>
  72 #include <net/ethernet.h>
  73
  74 #include <netinet/in.h>
  75 #include <net/ipfw/ip_fw.h>
  76
  77 #include <netgraph/ng_message.h>
  78 #include <netgraph/netgraph.h>
  79 #include <netgraph/ng_parse.h>
  80 #include "ng_bridge.h"
  81 #include <netgraph/ether/ng_ether.h>
  82
  83 /* Per-link private data */
  84 struct ng_bridge_link {
  85         hook_p                          hook;           /* netgraph hook */
  86         u_int16_t                       loopCount;      /* loop ignore timer */
  87         struct ng_bridge_link_stats     stats;          /* link stats */
  88 };
  89
  90 /* Per-node private data */
  91 struct ng_bridge_private {
  92         struct ng_bridge_bucket *tab;           /* hash table bucket array */
  93         struct ng_bridge_link   *links[NG_BRIDGE_MAX_LINKS];
  94         struct ng_bridge_config conf;           /* node configuration */
  95         node_p                  node;           /* netgraph node */
  96         u_int                   numHosts;       /* num entries in table */
  97         u_int                   numBuckets;     /* num buckets in table */
  98         u_int                   hashMask;       /* numBuckets - 1 */
  99         int                     numLinks;       /* num connected links */
 100         struct callout          timer;          /* one second periodic timer */
 101 };
 102 typedef struct ng_bridge_private *priv_p;
 103
 104 /* Information about a host, stored in a hash table entry */
 105 struct ng_bridge_hent {
 106         struct ng_bridge_host           host;   /* actual host info */
 107         SLIST_ENTRY(ng_bridge_hent)     next;   /* next entry in bucket */
 108 };
 109
 110 /* Hash table bucket declaration */
 111 SLIST_HEAD(ng_bridge_bucket, ng_bridge_hent);
 112
 113 /* Netgraph node methods */
 114 static ng_constructor_t ng_bridge_constructor;
 115 static ng_rcvmsg_t      ng_bridge_rcvmsg;
 116 static ng_shutdown_t    ng_bridge_rmnode;
 117 static ng_newhook_t     ng_bridge_newhook;
 118 static ng_rcvdata_t     ng_bridge_rcvdata;
 119 static ng_disconnect_t  ng_bridge_disconnect;
 120
 121 /* Other internal functions */
 122 static struct   ng_bridge_host *ng_bridge_get(priv_p priv, const u_char *addr);
 123 static int      ng_bridge_put(priv_p priv, const u_char *addr, int linkNum);
 124 static void     ng_bridge_rehash(priv_p priv);
 125 static void     ng_bridge_remove_hosts(priv_p priv, int linkNum);
 126 static void     ng_bridge_timeout(void *arg);
 127 static const    char *ng_bridge_nodename(node_p node);
 128
 129 /* Ethernet broadcast */
 130 static const u_char ng_bridge_bcast_addr[ETHER_ADDR_LEN] =
 131     { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
 132
 133 /* Store each hook's link number in the private field */
 134 #define LINK_NUM(hook)          (*(u_int16_t *)(&(hook)->private))
 135
 136 /* Compare Ethernet addresses using 32 and 16 bit words instead of bytewise */
 137 #define ETHER_EQUAL(a,b)        (((const u_int32_t *)(a))[0] \
 138                                         == ((const u_int32_t *)(b))[0] \
 139                                     && ((const u_int16_t *)(a))[2] \
 140                                         == ((const u_int16_t *)(b))[2])
 141
 142 /* Minimum and maximum number of hash buckets. Must be a power of two. */
 143 #define MIN_BUCKETS             (1 << 5)        /* 32 */
 144 #define MAX_BUCKETS             (1 << 14)       /* 16384 */
 145
 146 /* Configuration default values */
 147 #define DEFAULT_LOOP_TIMEOUT    60
 148 #define DEFAULT_MAX_STALENESS   (15 * 60)       /* same as ARP timeout */
 149 #define DEFAULT_MIN_STABLE_AGE  1
 150
 151 /******************************************************************
 152                     NETGRAPH PARSE TYPES
 153 ******************************************************************/
 154
 155 /*
 156  * How to determine the length of the table returned by NGM_BRIDGE_GET_TABLE
 157  */
 158 static int
 159 ng_bridge_getTableLength(const struct ng_parse_type *type,
 160         const u_char *start, const u_char *buf)
 161 {
 162         const struct ng_bridge_host_ary *const hary
 163             = (const struct ng_bridge_host_ary *)(buf - sizeof(u_int32_t));
 164
 165         return hary->numHosts;
 166 }
 167
 168 /* Parse type for struct ng_bridge_host_ary */
 169 static const struct ng_parse_struct_field ng_bridge_host_type_fields[]
 170         = NG_BRIDGE_HOST_TYPE_INFO(&ng_ether_enaddr_type);
 171 static const struct ng_parse_type ng_bridge_host_type = {
 172         &ng_parse_struct_type,
 173         &ng_bridge_host_type_fields
 174 };
 175 static const struct ng_parse_array_info ng_bridge_hary_type_info = {
 176         &ng_bridge_host_type,
 177         ng_bridge_getTableLength
 178 };
 179 static const struct ng_parse_type ng_bridge_hary_type = {
 180         &ng_parse_array_type,
 181         &ng_bridge_hary_type_info
 182 };
 183 static const struct ng_parse_struct_field ng_bridge_host_ary_type_fields[]
 184         = NG_BRIDGE_HOST_ARY_TYPE_INFO(&ng_bridge_hary_type);
 185 static const struct ng_parse_type ng_bridge_host_ary_type = {
 186         &ng_parse_struct_type,
 187         &ng_bridge_host_ary_type_fields
 188 };
 189
 190 /* Parse type for struct ng_bridge_config */
 191 static const struct ng_parse_fixedarray_info ng_bridge_ipfwary_type_info = {
 192         &ng_parse_uint8_type,
 193         NG_BRIDGE_MAX_LINKS
 194 };
 195 static const struct ng_parse_type ng_bridge_ipfwary_type = {
 196         &ng_parse_fixedarray_type,
 197         &ng_bridge_ipfwary_type_info
 198 };
 199 static const struct ng_parse_struct_field ng_bridge_config_type_fields[]
 200         = NG_BRIDGE_CONFIG_TYPE_INFO(&ng_bridge_ipfwary_type);
 201 static const struct ng_parse_type ng_bridge_config_type = {
 202         &ng_parse_struct_type,
 203         &ng_bridge_config_type_fields
 204 };
 205
 206 /* Parse type for struct ng_bridge_link_stat */
 207 static const struct ng_parse_struct_field ng_bridge_stats_type_fields[]
 208         = NG_BRIDGE_STATS_TYPE_INFO;
 209 static const struct ng_parse_type ng_bridge_stats_type = {
 210         &ng_parse_struct_type,
 211         &ng_bridge_stats_type_fields
 212 };
 213
 214 /* List of commands and how to convert arguments to/from ASCII */
 215 static const struct ng_cmdlist ng_bridge_cmdlist[] = {
 216         {
 217           NGM_BRIDGE_COOKIE,
 218           NGM_BRIDGE_SET_CONFIG,
 219           "setconfig",
 220           &ng_bridge_config_type,
 221           NULL
 222         },
 223         {
 224           NGM_BRIDGE_COOKIE,
 225           NGM_BRIDGE_GET_CONFIG,
 226           "getconfig",
 227           NULL,
 228           &ng_bridge_config_type
 229         },
 230         {
 231           NGM_BRIDGE_COOKIE,
 232           NGM_BRIDGE_RESET,
 233           "reset",
 234           NULL,
 235           NULL
 236         },
 237         {
 238           NGM_BRIDGE_COOKIE,
 239           NGM_BRIDGE_GET_STATS,
 240           "getstats",
 241           &ng_parse_uint32_type,
 242           &ng_bridge_stats_type
 243         },
 244         {
 245           NGM_BRIDGE_COOKIE,
 246           NGM_BRIDGE_CLR_STATS,
 247           "clrstats",
 248           &ng_parse_uint32_type,
 249           NULL
 250         },
 251         {
 252           NGM_BRIDGE_COOKIE,
 253           NGM_BRIDGE_GETCLR_STATS,
 254           "getclrstats",
 255           &ng_parse_uint32_type,
 256           &ng_bridge_stats_type
 257         },
 258         {
 259           NGM_BRIDGE_COOKIE,
 260           NGM_BRIDGE_GET_TABLE,
 261           "gettable",
 262           NULL,
 263           &ng_bridge_host_ary_type
 264         },
 265         { 0 }
 266 };
 267
 268 /* Node type descriptor */
 269 static struct ng_type ng_bridge_typestruct = {
 270         NG_VERSION,
 271         NG_BRIDGE_NODE_TYPE,
 272         NULL,
 273         ng_bridge_constructor,
 274         ng_bridge_rcvmsg,
 275         ng_bridge_rmnode,
 276         ng_bridge_newhook,
 277         NULL,
 278         NULL,
 279         ng_bridge_rcvdata,
 280         ng_bridge_rcvdata,
 281         ng_bridge_disconnect,
 282         ng_bridge_cmdlist,
 283 };
 284 NETGRAPH_INIT(bridge, &ng_bridge_typestruct);
 285
 286 /* Depend on ng_ether so we can use the Ethernet parse type */
 287 MODULE_DEPEND(ng_bridge, ng_ether, NG_ABI_VERSION, NG_ABI_VERSION, NG_ABI_VERSION);
 288
 289 /******************************************************************
 290                     NETGRAPH NODE METHODS
 291 ******************************************************************/
 292
 293 /*
 294  * Node constructor
 295  */
 296 static int
 297 ng_bridge_constructor(node_p *nodep)
 298 {
 299         priv_p priv;
 300         int error;
 301
 302         /* Allocate and initialize private info */
 303         priv = kmalloc(sizeof(*priv), M_NETGRAPH, M_NOWAIT | M_ZERO);
 304         if (priv == NULL)
 305                 return (ENOMEM);
 306         callout_init(&priv->timer);
 307
 308         /* Allocate and initialize hash table, etc. */
 309         priv->tab = kmalloc(MIN_BUCKETS * sizeof(*priv->tab), M_NETGRAPH,
 310                             M_NOWAIT | M_ZERO);
 311         if (priv->tab == NULL) {
 312                 kfree(priv, M_NETGRAPH);
 313                 return (ENOMEM);
 314         }
 315         priv->numBuckets = MIN_BUCKETS;
 316         priv->hashMask = MIN_BUCKETS - 1;
 317         priv->conf.debugLevel = 1;
 318         priv->conf.loopTimeout = DEFAULT_LOOP_TIMEOUT;
 319         priv->conf.maxStaleness = DEFAULT_MAX_STALENESS;
 320         priv->conf.minStableAge = DEFAULT_MIN_STABLE_AGE;
 321
 322         /* Call superclass constructor */
 323         if ((error = ng_make_node_common(&ng_bridge_typestruct, nodep))) {
 324                 kfree(priv, M_NETGRAPH);
 325                 return (error);
 326         }
 327         (*nodep)->private = priv;
 328         priv->node = *nodep;
 329
 330         /* Start timer; timer is always running while node is alive */
 331         callout_reset(&priv->timer, hz, ng_bridge_timeout, priv->node);
 332
 333         /* Done */
 334         return (0);
 335 }
 336
 337 /*
 338  * Method for attaching a new hook
 339  */
 340 static  int
 341 ng_bridge_newhook(node_p node, hook_p hook, const char *name)
 342 {
 343         const priv_p priv = node->private;
 344
 345         /* Check for a link hook */
 346         if (strncmp(name, NG_BRIDGE_HOOK_LINK_PREFIX,
 347             strlen(NG_BRIDGE_HOOK_LINK_PREFIX)) == 0) {
 348                 const char *cp;
 349                 char *eptr;
 350                 u_long linkNum;
 351
 352                 cp = name + strlen(NG_BRIDGE_HOOK_LINK_PREFIX);
 353                 if (!isdigit(*cp) || (cp[0] == '0' && cp[1] != '\0'))
 354                         return (EINVAL);
 355                 linkNum = strtoul(cp, &eptr, 10);
 356                 if (*eptr != '\0' || linkNum >= NG_BRIDGE_MAX_LINKS)
 357                         return (EINVAL);
 358                 if (priv->links[linkNum] != NULL)
 359                         return (EISCONN);
 360                 priv->links[linkNum] = kmalloc(sizeof(*priv->links[linkNum]),
 361                                                M_NETGRAPH, M_NOWAIT);
 362                 if (priv->links[linkNum] == NULL)
 363                         return (ENOMEM);
 364                 bzero(priv->links[linkNum], sizeof(*priv->links[linkNum]));
 365                 priv->links[linkNum]->hook = hook;
 366                 LINK_NUM(hook) = linkNum;
 367                 priv->numLinks++;
 368                 return (0);
 369         }
 370
 371         /* Unknown hook name */
 372         return (EINVAL);
 373 }
 374
 375 /*
 376  * Receive a control message
 377  */
 378 static int
 379 ng_bridge_rcvmsg(node_p node, struct ng_mesg *msg,
 380         const char *retaddr, struct ng_mesg **rptr)
 381 {
 382         const priv_p priv = node->private;
 383         struct ng_mesg *resp = NULL;
 384         int error = 0;
 385
 386         switch (msg->header.typecookie) {
 387         case NGM_BRIDGE_COOKIE:
 388                 switch (msg->header.cmd) {
 389                 case NGM_BRIDGE_GET_CONFIG:
 390                     {
 391                         struct ng_bridge_config *conf;
 392
 393                         NG_MKRESPONSE(resp, msg,
 394                             sizeof(struct ng_bridge_config), M_NOWAIT);
 395                         if (resp == NULL) {
 396                                 error = ENOMEM;
 397                                 break;
 398                         }
 399                         conf = (struct ng_bridge_config *)resp->data;
 400                         *conf = priv->conf;     /* no sanity checking needed */
 401                         break;
 402                     }
 403                 case NGM_BRIDGE_SET_CONFIG:
 404                     {
 405                         struct ng_bridge_config *conf;
 406                         int i;
 407
 408                         if (msg->header.arglen
 409                             != sizeof(struct ng_bridge_config)) {
 410                                 error = EINVAL;
 411                                 break;
 412                         }
 413                         conf = (struct ng_bridge_config *)msg->data;
 414                         priv->conf = *conf;
 415                         for (i = 0; i < NG_BRIDGE_MAX_LINKS; i++)
 416                                 priv->conf.ipfw[i] = !!priv->conf.ipfw[i];
 417                         break;
 418                     }
 419                 case NGM_BRIDGE_RESET:
 420                     {
 421                         int i;
 422
 423                         /* Flush all entries in the hash table */
 424                         ng_bridge_remove_hosts(priv, -1);
 425
 426                         /* Reset all loop detection counters and stats */
 427                         for (i = 0; i < NG_BRIDGE_MAX_LINKS; i++) {
 428                                 if (priv->links[i] == NULL)
 429                                         continue;
 430                                 priv->links[i]->loopCount = 0;
 431                                 bzero(&priv->links[i]->stats,
 432                                     sizeof(priv->links[i]->stats));
 433                         }
 434                         break;
 435                     }
 436                 case NGM_BRIDGE_GET_STATS:
 437                 case NGM_BRIDGE_CLR_STATS:
 438                 case NGM_BRIDGE_GETCLR_STATS:
 439                     {
 440                         struct ng_bridge_link *link;
 441                         int linkNum;
 442
 443                         /* Get link number */
 444                         if (msg->header.arglen != sizeof(u_int32_t)) {
 445                                 error = EINVAL;
 446                                 break;
 447                         }
 448                         linkNum = *((u_int32_t *)msg->data);
 449                         if (linkNum < 0 || linkNum >= NG_BRIDGE_MAX_LINKS) {
 450                                 error = EINVAL;
 451                                 break;
 452                         }
 453                         if ((link = priv->links[linkNum]) == NULL) {
 454                                 error = ENOTCONN;
 455                                 break;
 456                         }
 457
 458                         /* Get/clear stats */
 459                         if (msg->header.cmd != NGM_BRIDGE_CLR_STATS) {
 460                                 NG_MKRESPONSE(resp, msg,
 461                                     sizeof(link->stats), M_NOWAIT);
 462                                 if (resp == NULL) {
 463                                         error = ENOMEM;
 464                                         break;
 465                                 }
 466                                 bcopy(&link->stats,
 467                                     resp->data, sizeof(link->stats));
 468                         }
 469                         if (msg->header.cmd != NGM_BRIDGE_GET_STATS)
 470                                 bzero(&link->stats, sizeof(link->stats));
 471                         break;
 472                     }
 473                 case NGM_BRIDGE_GET_TABLE:
 474                     {
 475                         struct ng_bridge_host_ary *ary;
 476                         struct ng_bridge_hent *hent;
 477                         int i = 0, bucket;
 478
 479                         NG_MKRESPONSE(resp, msg, sizeof(*ary)
 480                             + (priv->numHosts * sizeof(*ary->hosts)), M_NOWAIT);
 481                         if (resp == NULL) {
 482                                 error = ENOMEM;
 483                                 break;
 484                         }
 485                         ary = (struct ng_bridge_host_ary *)resp->data;
 486                         ary->numHosts = priv->numHosts;
 487                         for (bucket = 0; bucket < priv->numBuckets; bucket++) {
 488                                 SLIST_FOREACH(hent, &priv->tab[bucket], next)
 489                                         ary->hosts[i++] = hent->host;
 490                         }
 491                         break;
 492                     }
 493                 default:
 494                         error = EINVAL;
 495                         break;
 496                 }
 497                 break;
 498         default:
 499                 error = EINVAL;
 500                 break;
 501         }
 502
 503         /* Done */
 504         if (rptr)
 505                 *rptr = resp;
 506         else if (resp != NULL)
 507                 kfree(resp, M_NETGRAPH);
 508         kfree(msg, M_NETGRAPH);
 509         return (error);
 510 }
 511
 512 /*
 513  * Receive data on a hook
 514  */
 515 static int
 516 ng_bridge_rcvdata(hook_p hook, struct mbuf *m, meta_p meta)
 517 {
 518         const node_p node = hook->node;
 519         const priv_p priv = node->private;
 520         struct ng_bridge_host *host;
 521         struct ng_bridge_link *link;
 522         struct ether_header *eh;
 523         int error = 0, linkNum;
 524         int i, manycast;
 525
 526         /* Get link number */
 527         linkNum = LINK_NUM(hook);
 528         KASSERT(linkNum >= 0 && linkNum < NG_BRIDGE_MAX_LINKS,
 529             ("%s: linkNum=%u", __func__, linkNum));
 530         link = priv->links[linkNum];
 531         KASSERT(link != NULL, ("%s: link%d null", __func__, linkNum));
 532
 533         /* Sanity check packet and pull up header */
 534         if (m->m_pkthdr.len < ETHER_HDR_LEN) {
 535                 link->stats.recvRunts++;
 536                 NG_FREE_DATA(m, meta);
 537                 return (EINVAL);
 538         }
 539         if (m->m_len < ETHER_HDR_LEN && !(m = m_pullup(m, ETHER_HDR_LEN))) {
 540                 link->stats.memoryFailures++;
 541                 NG_FREE_META(meta);
 542                 return (ENOBUFS);
 543         }
 544         eh = mtod(m, struct ether_header *);
 545         if ((eh->ether_shost[0] & 1) != 0) {
 546                 link->stats.recvInvalid++;
 547                 NG_FREE_DATA(m, meta);
 548                 return (EINVAL);
 549         }
 550
 551         /* Is link disabled due to a loopback condition? */
 552         if (link->loopCount != 0) {
 553                 link->stats.loopDrops++;
 554                 NG_FREE_DATA(m, meta);
 555                 return (ELOOP);         /* XXX is this an appropriate error? */
 556         }
 557
 558         /* Update stats */
 559         link->stats.recvPackets++;
 560         link->stats.recvOctets += m->m_pkthdr.len;
 561         if ((manycast = (eh->ether_dhost[0] & 1)) != 0) {
 562                 if (ETHER_EQUAL(eh->ether_dhost, ng_bridge_bcast_addr)) {
 563                         link->stats.recvBroadcasts++;
 564                         manycast = 2;
 565                 } else
 566                         link->stats.recvMulticasts++;
 567         }
 568
 569         /* Look up packet's source Ethernet address in hashtable */
 570         if ((host = ng_bridge_get(priv, eh->ether_shost)) != NULL) {
 571
 572                 /* Update time since last heard from this host */
 573                 host->staleness = 0;
 574
 575                 /* Did host jump to a different link? */
 576                 if (host->linkNum != linkNum) {
 577
 578                         /*
 579                          * If the host's old link was recently established
 580                          * on the old link and it's already jumped to a new
 581                          * link, declare a loopback condition.
 582                          */
 583                         if (host->age < priv->conf.minStableAge) {
 584
 585                                 /* Log the problem */
 586                                 if (priv->conf.debugLevel >= 2) {
 587                                         struct ifnet *ifp = m->m_pkthdr.rcvif;
 588                                         char suffix[32];
 589
 590                                         if (ifp != NULL)
 591                                                 ksnprintf(suffix, sizeof(suffix),
 592                                                     " (%s)", ifp->if_xname);
 593                                         else
 594                                                 *suffix = '\0';
 595                                         log(LOG_WARNING, "ng_bridge: %s:"
 596                                             " loopback detected on %s%s\n",
 597                                             ng_bridge_nodename(node),
 598                                             hook->name, suffix);
 599                                 }
 600
 601                                 /* Mark link as linka non grata */
 602                                 link->loopCount = priv->conf.loopTimeout;
 603                                 link->stats.loopDetects++;
 604
 605                                 /* Forget all hosts on this link */
 606                                 ng_bridge_remove_hosts(priv, linkNum);
 607
 608                                 /* Drop packet */
 609                                 link->stats.loopDrops++;
 610                                 NG_FREE_DATA(m, meta);
 611                                 return (ELOOP);         /* XXX appropriate? */
 612                         }
 613
 614                         /* Move host over to new link */
 615                         host->linkNum = linkNum;
 616                         host->age = 0;
 617                 }
 618         } else {
 619                 if (!ng_bridge_put(priv, eh->ether_shost, linkNum)) {
 620                         link->stats.memoryFailures++;
 621                         NG_FREE_DATA(m, meta);
 622                         return (ENOMEM);
 623                 }
 624         }
 625
 626         /* Run packet through ipfw processing, if enabled */
 627         if (priv->conf.ipfw[linkNum] && fw_enable && ip_fw_chk_ptr != NULL) {
 628                 /* XXX not implemented yet */
 629         }
 630
 631         /*
 632          * If unicast and destination host known, deliver to host's link,
 633          * unless it is the same link as the packet came in on.
 634          */
 635         if (!manycast) {
 636
 637                 /* Determine packet destination link */
 638                 if ((host = ng_bridge_get(priv, eh->ether_dhost)) != NULL) {
 639                         struct ng_bridge_link *const destLink
 640                             = priv->links[host->linkNum];
 641
 642                         /* If destination same as incoming link, do nothing */
 643                         KASSERT(destLink != NULL,
 644                             ("%s: link%d null", __func__, host->linkNum));
 645                         if (destLink == link) {
 646                                 NG_FREE_DATA(m, meta);
 647                                 return (0);
 648                         }
 649
 650                         /* Deliver packet out the destination link */
 651                         destLink->stats.xmitPackets++;
 652                         destLink->stats.xmitOctets += m->m_pkthdr.len;
 653                         NG_SEND_DATA(error, destLink->hook, m, meta);
 654                         return (error);
 655                 }
 656
 657                 /* Destination host is not known */
 658                 link->stats.recvUnknown++;
 659         }
 660
 661         /* Distribute unknown, multicast, broadcast pkts to all other links */
 662         for (linkNum = i = 0; i < priv->numLinks - 1; linkNum++) {
 663                 struct ng_bridge_link *const destLink = priv->links[linkNum];
 664                 meta_p meta2 = NULL;
 665                 struct mbuf *m2;
 666
 667                 /* Skip incoming link and disconnected links */
 668                 if (destLink == NULL || destLink == link)
 669                         continue;
 670
 671                 /* Copy mbuf and meta info */
 672                 if (++i == priv->numLinks - 1) {                /* last link */
 673                         m2 = m;
 674                         meta2 = meta;
 675                 }  else {
 676                         m2 = m_dup(m, M_NOWAIT);        /* XXX m_copypacket() */
 677                         if (m2 == NULL) {
 678                                 link->stats.memoryFailures++;
 679                                 NG_FREE_DATA(m, meta);
 680                                 return (ENOBUFS);
 681                         }
 682                         if (meta != NULL
 683                             && (meta2 = ng_copy_meta(meta)) == NULL) {
 684                                 link->stats.memoryFailures++;
 685                                 m_freem(m2);
 686                                 NG_FREE_DATA(m, meta);
 687                                 return (ENOMEM);
 688                         }
 689                 }
 690
 691                 /* Update stats */
 692                 destLink->stats.xmitPackets++;
 693                 destLink->stats.xmitOctets += m->m_pkthdr.len;
 694                 switch (manycast) {
 695                 case 0:                                 /* unicast */
 696                         break;
 697                 case 1:                                 /* multicast */
 698                         destLink->stats.xmitMulticasts++;
 699                         break;
 700                 case 2:                                 /* broadcast */
 701                         destLink->stats.xmitBroadcasts++;
 702                         break;
 703                 }
 704
 705                 /* Send packet */
 706                 NG_SEND_DATA(error, destLink->hook, m2, meta2);
 707         }
 708         return (error);
 709 }
 710
 711 /*
 712  * Shutdown node
 713  */
 714 static int
 715 ng_bridge_rmnode(node_p node)
 716 {
 717         const priv_p priv = node->private;
 718
 719         /*
 720          * Shut down everything except the timer. There's no way to
 721          * avoid another possible timeout event (it may have already
 722          * been dequeued), so we can't free the node yet.
 723          */
 724         ng_unname(node);
 725         ng_cutlinks(node);              /* frees all link and host info */
 726         KASSERT(priv->numLinks == 0 && priv->numHosts == 0,
 727             ("%s: numLinks=%d numHosts=%d",
 728             __func__, priv->numLinks, priv->numHosts));
 729         kfree(priv->tab, M_NETGRAPH);
 730
 731         /* NG_INVALID flag is now set so node will be freed at next timeout */
 732         return (0);
 733 }
 734
 735 /*
 736  * Hook disconnection.
 737  */
 738 static int
 739 ng_bridge_disconnect(hook_p hook)
 740 {
 741         const priv_p priv = hook->node->private;
 742         int linkNum;
 743
 744         /* Get link number */
 745         linkNum = LINK_NUM(hook);
 746         KASSERT(linkNum >= 0 && linkNum < NG_BRIDGE_MAX_LINKS,
 747             ("%s: linkNum=%u", __func__, linkNum));
 748
 749         /* Remove all hosts associated with this link */
 750         ng_bridge_remove_hosts(priv, linkNum);
 751
 752         /* Free associated link information */
 753         KASSERT(priv->links[linkNum] != NULL, ("%s: no link", __func__));
 754         kfree(priv->links[linkNum], M_NETGRAPH);
 755         priv->links[linkNum] = NULL;
 756         priv->numLinks--;
 757
 758         /* If no more hooks, go away */
 759         if (hook->node->numhooks == 0)
 760                 ng_rmnode(hook->node);
 761         return (0);
 762 }
 763
 764 /******************************************************************
 765                     HASH TABLE FUNCTIONS
 766 ******************************************************************/
 767
 768 /*
 769  * Hash algorithm
 770  *
 771  * Only hashing bytes 3-6 of the Ethernet address is sufficient and fast.
 772  */
 773 #define HASH(addr,mask)         ( (((const u_int16_t *)(addr))[0]       \
 774                                  ^ ((const u_int16_t *)(addr))[1]       \
 775                                  ^ ((const u_int16_t *)(addr))[2]) & (mask) )
 776
 777 /*
 778  * Find a host entry in the table.
 779  */
 780 static struct ng_bridge_host *
 781 ng_bridge_get(priv_p priv, const u_char *addr)
 782 {
 783         const int bucket = HASH(addr, priv->hashMask);
 784         struct ng_bridge_hent *hent;
 785
 786         SLIST_FOREACH(hent, &priv->tab[bucket], next) {
 787                 if (ETHER_EQUAL(hent->host.addr, addr))
 788                         return (&hent->host);
 789         }
 790         return (NULL);
 791 }
 792
 793 /*
 794  * Add a new host entry to the table. This assumes the host doesn't
 795  * already exist in the table. Returns 1 on success, 0 if there
 796  * was a memory allocation failure.
 797  */
 798 static int
 799 ng_bridge_put(priv_p priv, const u_char *addr, int linkNum)
 800 {
 801         const int bucket = HASH(addr, priv->hashMask);
 802         struct ng_bridge_hent *hent;
 803
 804 #ifdef INVARIANTS
 805         char ethstr[ETHER_ADDRSTRLEN + 1];
 806
 807         /* Assert that entry does not already exist in hashtable */
 808         SLIST_FOREACH(hent, &priv->tab[bucket], next) {
 809                 KASSERT(!ETHER_EQUAL(hent->host.addr, addr),
 810                     ("%s: entry %s exists in table", __func__, kether_ntoa(addr, ethstr)));
 811         }
 812 #endif
 813
 814         /* Allocate and initialize new hashtable entry */
 815         hent = kmalloc(sizeof(*hent), M_NETGRAPH, M_NOWAIT);
 816         if (hent == NULL)
 817                 return (0);
 818         bcopy(addr, hent->host.addr, ETHER_ADDR_LEN);
 819         hent->host.linkNum = linkNum;
 820         hent->host.staleness = 0;
 821         hent->host.age = 0;
 822
 823         /* Add new element to hash bucket */
 824         SLIST_INSERT_HEAD(&priv->tab[bucket], hent, next);
 825         priv->numHosts++;
 826
 827         /* Resize table if necessary */
 828         ng_bridge_rehash(priv);
 829         return (1);
 830 }
 831
 832 /*
 833  * Resize the hash table. We try to maintain the number of buckets
 834  * such that the load factor is in the range 0.25 to 1.0.
 835  *
 836  * If we can't get the new memory then we silently fail. This is OK
 837  * because things will still work and we'll try again soon anyway.
 838  */
 839 static void
 840 ng_bridge_rehash(priv_p priv)
 841 {
 842         struct ng_bridge_bucket *newTab;
 843         int oldBucket, newBucket;
 844         int newNumBuckets;
 845         u_int newMask;
 846
 847         /* Is table too full or too empty? */
 848         if (priv->numHosts > priv->numBuckets
 849             && (priv->numBuckets << 1) <= MAX_BUCKETS)
 850                 newNumBuckets = priv->numBuckets << 1;
 851         else if (priv->numHosts < (priv->numBuckets >> 2)
 852             && (priv->numBuckets >> 2) >= MIN_BUCKETS)
 853                 newNumBuckets = priv->numBuckets >> 2;
 854         else
 855                 return;
 856         newMask = newNumBuckets - 1;
 857
 858         /* Allocate and initialize new table */
 859         newTab = kmalloc(newNumBuckets * sizeof(*newTab), M_NETGRAPH,
 860                          M_NOWAIT | M_ZERO);
 861         if (newTab == NULL)
 862                 return;
 863
 864         /* Move all entries from old table to new table */
 865         for (oldBucket = 0; oldBucket < priv->numBuckets; oldBucket++) {
 866                 struct ng_bridge_bucket *const oldList = &priv->tab[oldBucket];
 867
 868                 while (!SLIST_EMPTY(oldList)) {
 869                         struct ng_bridge_hent *const hent
 870                             = SLIST_FIRST(oldList);
 871
 872                         SLIST_REMOVE_HEAD(oldList, next);
 873                         newBucket = HASH(hent->host.addr, newMask);
 874                         SLIST_INSERT_HEAD(&newTab[newBucket], hent, next);
 875                 }
 876         }
 877
 878         /* Replace old table with new one */
 879         if (priv->conf.debugLevel >= 3) {
 880                 log(LOG_INFO, "ng_bridge: %s: table size %d -> %d\n",
 881                     ng_bridge_nodename(priv->node),
 882                     priv->numBuckets, newNumBuckets);
 883         }
 884         kfree(priv->tab, M_NETGRAPH);
 885         priv->numBuckets = newNumBuckets;
 886         priv->hashMask = newMask;
 887         priv->tab = newTab;
 888         return;
 889 }
 890
 891 /******************************************************************
 892                     MISC FUNCTIONS
 893 ******************************************************************/
 894
 895 /*
 896  * Remove all hosts associated with a specific link from the hashtable.
 897  * If linkNum == -1, then remove all hosts in the table.
 898  */
 899 static void
 900 ng_bridge_remove_hosts(priv_p priv, int linkNum)
 901 {
 902         int bucket;
 903
 904         for (bucket = 0; bucket < priv->numBuckets; bucket++) {
 905                 struct ng_bridge_hent **hptr = &SLIST_FIRST(&priv->tab[bucket]);
 906
 907                 while (*hptr != NULL) {
 908                         struct ng_bridge_hent *const hent = *hptr;
 909
 910                         if (linkNum == -1 || hent->host.linkNum == linkNum) {
 911                                 *hptr = SLIST_NEXT(hent, next);
 912                                 kfree(hent, M_NETGRAPH);
 913                                 priv->numHosts--;
 914                         } else
 915                                 hptr = &SLIST_NEXT(hent, next);
 916                 }
 917         }
 918 }
 919
 920 /*
 921  * Handle our once-per-second timeout event. We do two things:
 922  * we decrement link->loopCount for those links being muted due to
 923  * a detected loopback condition, and we remove any hosts from
 924  * the hashtable whom we haven't heard from in a long while.
 925  *
 926  * If the node has the NG_INVALID flag set, our job is to kill it.
 927  */
 928 static void
 929 ng_bridge_timeout(void *arg)
 930 {
 931         const node_p node = arg;
 932         const priv_p priv = node->private;
 933         int bucket;
 934         int counter = 0;
 935         int linkNum;
 936         char ethstr[ETHER_ADDRSTRLEN + 1];
 937
 938         /* If node was shut down, this is the final lingering timeout */
 939         crit_enter();
 940         if ((node->flags & NG_INVALID) != 0) {
 941                 kfree(priv, M_NETGRAPH);
 942                 node->private = NULL;
 943                 ng_unref(node);
 944                 crit_exit();
 945                 return;
 946         }
 947
 948         /* Register a new timeout, keeping the existing node reference */
 949         callout_reset(&priv->timer, hz, ng_bridge_timeout, node);
 950
 951         /* Update host time counters and remove stale entries */
 952         for (bucket = 0; bucket < priv->numBuckets; bucket++) {
 953                 struct ng_bridge_hent **hptr = &SLIST_FIRST(&priv->tab[bucket]);
 954
 955                 while (*hptr != NULL) {
 956                         struct ng_bridge_hent *const hent = *hptr;
 957
 958                         /* Make sure host's link really exists */
 959                         KASSERT(priv->links[hent->host.linkNum] != NULL,
 960                             ("%s: host %s on nonexistent link %d",
 961                             __func__, kether_ntoa(hent->host.addr, ethstr),
 962                             hent->host.linkNum));
 963
 964                         /* Remove hosts we haven't heard from in a while */
 965                         if (++hent->host.staleness >= priv->conf.maxStaleness) {
 966                                 *hptr = SLIST_NEXT(hent, next);
 967                                 kfree(hent, M_NETGRAPH);
 968                                 priv->numHosts--;
 969                         } else {
 970                                 if (hent->host.age < 0xffff)
 971                                         hent->host.age++;
 972                                 hptr = &SLIST_NEXT(hent, next);
 973                                 counter++;
 974                         }
 975                 }
 976         }
 977         KASSERT(priv->numHosts == counter,
 978             ("%s: hosts: %d != %d", __func__, priv->numHosts, counter));
 979
 980         /* Decrease table size if necessary */
 981         ng_bridge_rehash(priv);
 982
 983         /* Decrease loop counter on muted looped back links */
 984         for (counter = linkNum = 0; linkNum < NG_BRIDGE_MAX_LINKS; linkNum++) {
 985                 struct ng_bridge_link *const link = priv->links[linkNum];
 986
 987                 if (link != NULL) {
 988                         if (link->loopCount != 0) {
 989                                 link->loopCount--;
 990                                 if (link->loopCount == 0
 991                                     && priv->conf.debugLevel >= 2) {
 992                                         log(LOG_INFO, "ng_bridge: %s:"
 993                                             " restoring looped back link%d\n",
 994                                             ng_bridge_nodename(node), linkNum);
 995                                 }
 996                         }
 997                         counter++;
 998                 }
 999         }
1000         KASSERT(priv->numLinks == counter,
1001             ("%s: links: %d != %d", __func__, priv->numLinks, counter));
1002
1003         /* Done */
1004         crit_exit();
1005 }
1006
1007 /*
1008  * Return node's "name", even if it doesn't have one.
1009  */
1010 static const char *
1011 ng_bridge_nodename(node_p node)
1012 {
1013         static char name[NG_NODESIZ];
1014
1015         if (node->name != NULL)
1016                 ksnprintf(name, sizeof(name), "%s", node->name);
1017         else
1018                 ksnprintf(name, sizeof(name), "[%x]", ng_node2ID(node));
1019         return name;
1020 }
1021