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  * $DragonFly: src/sys/netgraph/bridge/ng_bridge.c,v 1.7 2005/02/17 13:59:59 joerg Exp $
  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/malloc.h>
  65 #include <sys/mbuf.h>
  66 #include <sys/errno.h>
  67 #include <sys/syslog.h>
  68 #include <sys/socket.h>
  69 #include <sys/ctype.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, 1, 1, 1);
 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         MALLOC(priv, priv_p, sizeof(*priv), M_NETGRAPH, M_NOWAIT);
 304         if (priv == NULL)
 305                 return (ENOMEM);
 306         bzero(priv, sizeof(*priv));
 307         callout_init(&priv->timer);
 308
 309         /* Allocate and initialize hash table, etc. */
 310         MALLOC(priv->tab, struct ng_bridge_bucket *,
 311             MIN_BUCKETS * sizeof(*priv->tab), M_NETGRAPH, M_NOWAIT);
 312         if (priv->tab == NULL) {
 313                 FREE(priv, M_NETGRAPH);
 314                 return (ENOMEM);
 315         }
 316         bzero(priv->tab, MIN_BUCKETS * sizeof(*priv->tab));  /* init SLIST's */
 317         priv->numBuckets = MIN_BUCKETS;
 318         priv->hashMask = MIN_BUCKETS - 1;
 319         priv->conf.debugLevel = 1;
 320         priv->conf.loopTimeout = DEFAULT_LOOP_TIMEOUT;
 321         priv->conf.maxStaleness = DEFAULT_MAX_STALENESS;
 322         priv->conf.minStableAge = DEFAULT_MIN_STABLE_AGE;
 323
 324         /* Call superclass constructor */
 325         if ((error = ng_make_node_common(&ng_bridge_typestruct, nodep))) {
 326                 FREE(priv, M_NETGRAPH);
 327                 return (error);
 328         }
 329         (*nodep)->private = priv;
 330         priv->node = *nodep;
 331
 332         /* Start timer; timer is always running while node is alive */
 333         callout_reset(&priv->timer, hz, ng_bridge_timeout, priv->node);
 334
 335         /* Done */
 336         return (0);
 337 }
 338
 339 /*
 340  * Method for attaching a new hook
 341  */
 342 static  int
 343 ng_bridge_newhook(node_p node, hook_p hook, const char *name)
 344 {
 345         const priv_p priv = node->private;
 346
 347         /* Check for a link hook */
 348         if (strncmp(name, NG_BRIDGE_HOOK_LINK_PREFIX,
 349             strlen(NG_BRIDGE_HOOK_LINK_PREFIX)) == 0) {
 350                 const char *cp;
 351                 char *eptr;
 352                 u_long linkNum;
 353
 354                 cp = name + strlen(NG_BRIDGE_HOOK_LINK_PREFIX);
 355                 if (!isdigit(*cp) || (cp[0] == '0' && cp[1] != '\0'))
 356                         return (EINVAL);
 357                 linkNum = strtoul(cp, &eptr, 10);
 358                 if (*eptr != '\0' || linkNum >= NG_BRIDGE_MAX_LINKS)
 359                         return (EINVAL);
 360                 if (priv->links[linkNum] != NULL)
 361                         return (EISCONN);
 362                 MALLOC(priv->links[linkNum], struct ng_bridge_link *,
 363                     sizeof(*priv->links[linkNum]), M_NETGRAPH, M_NOWAIT);
 364                 if (priv->links[linkNum] == NULL)
 365                         return (ENOMEM);
 366                 bzero(priv->links[linkNum], sizeof(*priv->links[linkNum]));
 367                 priv->links[linkNum]->hook = hook;
 368                 LINK_NUM(hook) = linkNum;
 369                 priv->numLinks++;
 370                 return (0);
 371         }
 372
 373         /* Unknown hook name */
 374         return (EINVAL);
 375 }
 376
 377 /*
 378  * Receive a control message
 379  */
 380 static int
 381 ng_bridge_rcvmsg(node_p node, struct ng_mesg *msg,
 382         const char *retaddr, struct ng_mesg **rptr)
 383 {
 384         const priv_p priv = node->private;
 385         struct ng_mesg *resp = NULL;
 386         int error = 0;
 387
 388         switch (msg->header.typecookie) {
 389         case NGM_BRIDGE_COOKIE:
 390                 switch (msg->header.cmd) {
 391                 case NGM_BRIDGE_GET_CONFIG:
 392                     {
 393                         struct ng_bridge_config *conf;
 394
 395                         NG_MKRESPONSE(resp, msg,
 396                             sizeof(struct ng_bridge_config), M_NOWAIT);
 397                         if (resp == NULL) {
 398                                 error = ENOMEM;
 399                                 break;
 400                         }
 401                         conf = (struct ng_bridge_config *)resp->data;
 402                         *conf = priv->conf;     /* no sanity checking needed */
 403                         break;
 404                     }
 405                 case NGM_BRIDGE_SET_CONFIG:
 406                     {
 407                         struct ng_bridge_config *conf;
 408                         int i;
 409
 410                         if (msg->header.arglen
 411                             != sizeof(struct ng_bridge_config)) {
 412                                 error = EINVAL;
 413                                 break;
 414                         }
 415                         conf = (struct ng_bridge_config *)msg->data;
 416                         priv->conf = *conf;
 417                         for (i = 0; i < NG_BRIDGE_MAX_LINKS; i++)
 418                                 priv->conf.ipfw[i] = !!priv->conf.ipfw[i];
 419                         break;
 420                     }
 421                 case NGM_BRIDGE_RESET:
 422                     {
 423                         int i;
 424
 425                         /* Flush all entries in the hash table */
 426                         ng_bridge_remove_hosts(priv, -1);
 427
 428                         /* Reset all loop detection counters and stats */
 429                         for (i = 0; i < NG_BRIDGE_MAX_LINKS; i++) {
 430                                 if (priv->links[i] == NULL)
 431                                         continue;
 432                                 priv->links[i]->loopCount = 0;
 433                                 bzero(&priv->links[i]->stats,
 434                                     sizeof(priv->links[i]->stats));
 435                         }
 436                         break;
 437                     }
 438                 case NGM_BRIDGE_GET_STATS:
 439                 case NGM_BRIDGE_CLR_STATS:
 440                 case NGM_BRIDGE_GETCLR_STATS:
 441                     {
 442                         struct ng_bridge_link *link;
 443                         int linkNum;
 444
 445                         /* Get link number */
 446                         if (msg->header.arglen != sizeof(u_int32_t)) {
 447                                 error = EINVAL;
 448                                 break;
 449                         }
 450                         linkNum = *((u_int32_t *)msg->data);
 451                         if (linkNum < 0 || linkNum >= NG_BRIDGE_MAX_LINKS) {
 452                                 error = EINVAL;
 453                                 break;
 454                         }
 455                         if ((link = priv->links[linkNum]) == NULL) {
 456                                 error = ENOTCONN;
 457                                 break;
 458                         }
 459
 460                         /* Get/clear stats */
 461                         if (msg->header.cmd != NGM_BRIDGE_CLR_STATS) {
 462                                 NG_MKRESPONSE(resp, msg,
 463                                     sizeof(link->stats), M_NOWAIT);
 464                                 if (resp == NULL) {
 465                                         error = ENOMEM;
 466                                         break;
 467                                 }
 468                                 bcopy(&link->stats,
 469                                     resp->data, sizeof(link->stats));
 470                         }
 471                         if (msg->header.cmd != NGM_BRIDGE_GET_STATS)
 472                                 bzero(&link->stats, sizeof(link->stats));
 473                         break;
 474                     }
 475                 case NGM_BRIDGE_GET_TABLE:
 476                     {
 477                         struct ng_bridge_host_ary *ary;
 478                         struct ng_bridge_hent *hent;
 479                         int i = 0, bucket;
 480
 481                         NG_MKRESPONSE(resp, msg, sizeof(*ary)
 482                             + (priv->numHosts * sizeof(*ary->hosts)), M_NOWAIT);
 483                         if (resp == NULL) {
 484                                 error = ENOMEM;
 485                                 break;
 486                         }
 487                         ary = (struct ng_bridge_host_ary *)resp->data;
 488                         ary->numHosts = priv->numHosts;
 489                         for (bucket = 0; bucket < priv->numBuckets; bucket++) {
 490                                 SLIST_FOREACH(hent, &priv->tab[bucket], next)
 491                                         ary->hosts[i++] = hent->host;
 492                         }
 493                         break;
 494                     }
 495                 default:
 496                         error = EINVAL;
 497                         break;
 498                 }
 499                 break;
 500         default:
 501                 error = EINVAL;
 502                 break;
 503         }
 504
 505         /* Done */
 506         if (rptr)
 507                 *rptr = resp;
 508         else if (resp != NULL)
 509                 FREE(resp, M_NETGRAPH);
 510         FREE(msg, M_NETGRAPH);
 511         return (error);
 512 }
 513
 514 /*
 515  * Receive data on a hook
 516  */
 517 static int
 518 ng_bridge_rcvdata(hook_p hook, struct mbuf *m, meta_p meta)
 519 {
 520         const node_p node = hook->node;
 521         const priv_p priv = node->private;
 522         struct ng_bridge_host *host;
 523         struct ng_bridge_link *link;
 524         struct ether_header *eh;
 525         int error = 0, linkNum;
 526         int i, manycast;
 527
 528         /* Get link number */
 529         linkNum = LINK_NUM(hook);
 530         KASSERT(linkNum >= 0 && linkNum < NG_BRIDGE_MAX_LINKS,
 531             ("%s: linkNum=%u", __func__, linkNum));
 532         link = priv->links[linkNum];
 533         KASSERT(link != NULL, ("%s: link%d null", __func__, linkNum));
 534
 535         /* Sanity check packet and pull up header */
 536         if (m->m_pkthdr.len < ETHER_HDR_LEN) {
 537                 link->stats.recvRunts++;
 538                 NG_FREE_DATA(m, meta);
 539                 return (EINVAL);
 540         }
 541         if (m->m_len < ETHER_HDR_LEN && !(m = m_pullup(m, ETHER_HDR_LEN))) {
 542                 link->stats.memoryFailures++;
 543                 NG_FREE_META(meta);
 544                 return (ENOBUFS);
 545         }
 546         eh = mtod(m, struct ether_header *);
 547         if ((eh->ether_shost[0] & 1) != 0) {
 548                 link->stats.recvInvalid++;
 549                 NG_FREE_DATA(m, meta);
 550                 return (EINVAL);
 551         }
 552
 553         /* Is link disabled due to a loopback condition? */
 554         if (link->loopCount != 0) {
 555                 link->stats.loopDrops++;
 556                 NG_FREE_DATA(m, meta);
 557                 return (ELOOP);         /* XXX is this an appropriate error? */
 558         }
 559
 560         /* Update stats */
 561         link->stats.recvPackets++;
 562         link->stats.recvOctets += m->m_pkthdr.len;
 563         if ((manycast = (eh->ether_dhost[0] & 1)) != 0) {
 564                 if (ETHER_EQUAL(eh->ether_dhost, ng_bridge_bcast_addr)) {
 565                         link->stats.recvBroadcasts++;
 566                         manycast = 2;
 567                 } else
 568                         link->stats.recvMulticasts++;
 569         }
 570
 571         /* Look up packet's source Ethernet address in hashtable */
 572         if ((host = ng_bridge_get(priv, eh->ether_shost)) != NULL) {
 573
 574                 /* Update time since last heard from this host */
 575                 host->staleness = 0;
 576
 577                 /* Did host jump to a different link? */
 578                 if (host->linkNum != linkNum) {
 579
 580                         /*
 581                          * If the host's old link was recently established
 582                          * on the old link and it's already jumped to a new
 583                          * link, declare a loopback condition.
 584                          */
 585                         if (host->age < priv->conf.minStableAge) {
 586
 587                                 /* Log the problem */
 588                                 if (priv->conf.debugLevel >= 2) {
 589                                         struct ifnet *ifp = m->m_pkthdr.rcvif;
 590                                         char suffix[32];
 591
 592                                         if (ifp != NULL)
 593                                                 snprintf(suffix, sizeof(suffix),
 594                                                     " (%s)", ifp->if_xname);
 595                                         else
 596                                                 *suffix = '\0';
 597                                         log(LOG_WARNING, "ng_bridge: %s:"
 598                                             " loopback detected on %s%s\n",
 599                                             ng_bridge_nodename(node),
 600                                             hook->name, suffix);
 601                                 }
 602
 603                                 /* Mark link as linka non grata */
 604                                 link->loopCount = priv->conf.loopTimeout;
 605                                 link->stats.loopDetects++;
 606
 607                                 /* Forget all hosts on this link */
 608                                 ng_bridge_remove_hosts(priv, linkNum);
 609
 610                                 /* Drop packet */
 611                                 link->stats.loopDrops++;
 612                                 NG_FREE_DATA(m, meta);
 613                                 return (ELOOP);         /* XXX appropriate? */
 614                         }
 615
 616                         /* Move host over to new link */
 617                         host->linkNum = linkNum;
 618                         host->age = 0;
 619                 }
 620         } else {
 621                 if (!ng_bridge_put(priv, eh->ether_shost, linkNum)) {
 622                         link->stats.memoryFailures++;
 623                         NG_FREE_DATA(m, meta);
 624                         return (ENOMEM);
 625                 }
 626         }
 627
 628         /* Run packet through ipfw processing, if enabled */
 629         if (priv->conf.ipfw[linkNum] && fw_enable && ip_fw_chk_ptr != NULL) {
 630                 /* XXX not implemented yet */
 631         }
 632
 633         /*
 634          * If unicast and destination host known, deliver to host's link,
 635          * unless it is the same link as the packet came in on.
 636          */
 637         if (!manycast) {
 638
 639                 /* Determine packet destination link */
 640                 if ((host = ng_bridge_get(priv, eh->ether_dhost)) != NULL) {
 641                         struct ng_bridge_link *const destLink
 642                             = priv->links[host->linkNum];
 643
 644                         /* If destination same as incoming link, do nothing */
 645                         KASSERT(destLink != NULL,
 646                             ("%s: link%d null", __func__, host->linkNum));
 647                         if (destLink == link) {
 648                                 NG_FREE_DATA(m, meta);
 649                                 return (0);
 650                         }
 651
 652                         /* Deliver packet out the destination link */
 653                         destLink->stats.xmitPackets++;
 654                         destLink->stats.xmitOctets += m->m_pkthdr.len;
 655                         NG_SEND_DATA(error, destLink->hook, m, meta);
 656                         return (error);
 657                 }
 658
 659                 /* Destination host is not known */
 660                 link->stats.recvUnknown++;
 661         }
 662
 663         /* Distribute unknown, multicast, broadcast pkts to all other links */
 664         for (linkNum = i = 0; i < priv->numLinks - 1; linkNum++) {
 665                 struct ng_bridge_link *const destLink = priv->links[linkNum];
 666                 meta_p meta2 = NULL;
 667                 struct mbuf *m2;
 668
 669                 /* Skip incoming link and disconnected links */
 670                 if (destLink == NULL || destLink == link)
 671                         continue;
 672
 673                 /* Copy mbuf and meta info */
 674                 if (++i == priv->numLinks - 1) {                /* last link */
 675                         m2 = m;
 676                         meta2 = meta;
 677                 }  else {
 678                         m2 = m_dup(m, M_NOWAIT);        /* XXX m_copypacket() */
 679                         if (m2 == NULL) {
 680                                 link->stats.memoryFailures++;
 681                                 NG_FREE_DATA(m, meta);
 682                                 return (ENOBUFS);
 683                         }
 684                         if (meta != NULL
 685                             && (meta2 = ng_copy_meta(meta)) == NULL) {
 686                                 link->stats.memoryFailures++;
 687                                 m_freem(m2);
 688                                 NG_FREE_DATA(m, meta);
 689                                 return (ENOMEM);
 690                         }
 691                 }
 692
 693                 /* Update stats */
 694                 destLink->stats.xmitPackets++;
 695                 destLink->stats.xmitOctets += m->m_pkthdr.len;
 696                 switch (manycast) {
 697                 case 0:                                 /* unicast */
 698                         break;
 699                 case 1:                                 /* multicast */
 700                         destLink->stats.xmitMulticasts++;
 701                         break;
 702                 case 2:                                 /* broadcast */
 703                         destLink->stats.xmitBroadcasts++;
 704                         break;
 705                 }
 706
 707                 /* Send packet */
 708                 NG_SEND_DATA(error, destLink->hook, m2, meta2);
 709         }
 710         return (error);
 711 }
 712
 713 /*
 714  * Shutdown node
 715  */
 716 static int
 717 ng_bridge_rmnode(node_p node)
 718 {
 719         const priv_p priv = node->private;
 720
 721         /*
 722          * Shut down everything except the timer. There's no way to
 723          * avoid another possible timeout event (it may have already
 724          * been dequeued), so we can't free the node yet.
 725          */
 726         ng_unname(node);
 727         ng_cutlinks(node);              /* frees all link and host info */
 728         KASSERT(priv->numLinks == 0 && priv->numHosts == 0,
 729             ("%s: numLinks=%d numHosts=%d",
 730             __func__, priv->numLinks, priv->numHosts));
 731         FREE(priv->tab, M_NETGRAPH);
 732
 733         /* NG_INVALID flag is now set so node will be freed at next timeout */
 734         return (0);
 735 }
 736
 737 /*
 738  * Hook disconnection.
 739  */
 740 static int
 741 ng_bridge_disconnect(hook_p hook)
 742 {
 743         const priv_p priv = hook->node->private;
 744         int linkNum;
 745
 746         /* Get link number */
 747         linkNum = LINK_NUM(hook);
 748         KASSERT(linkNum >= 0 && linkNum < NG_BRIDGE_MAX_LINKS,
 749             ("%s: linkNum=%u", __func__, linkNum));
 750
 751         /* Remove all hosts associated with this link */
 752         ng_bridge_remove_hosts(priv, linkNum);
 753
 754         /* Free associated link information */
 755         KASSERT(priv->links[linkNum] != NULL, ("%s: no link", __func__));
 756         FREE(priv->links[linkNum], M_NETGRAPH);
 757         priv->links[linkNum] = NULL;
 758         priv->numLinks--;
 759
 760         /* If no more hooks, go away */
 761         if (hook->node->numhooks == 0)
 762                 ng_rmnode(hook->node);
 763         return (0);
 764 }
 765
 766 /******************************************************************
 767                     HASH TABLE FUNCTIONS
 768 ******************************************************************/
 769
 770 /*
 771  * Hash algorithm
 772  *
 773  * Only hashing bytes 3-6 of the Ethernet address is sufficient and fast.
 774  */
 775 #define HASH(addr,mask)         ( (((const u_int16_t *)(addr))[0]       \
 776                                  ^ ((const u_int16_t *)(addr))[1]       \
 777                                  ^ ((const u_int16_t *)(addr))[2]) & (mask) )
 778
 779 /*
 780  * Find a host entry in the table.
 781  */
 782 static struct ng_bridge_host *
 783 ng_bridge_get(priv_p priv, const u_char *addr)
 784 {
 785         const int bucket = HASH(addr, priv->hashMask);
 786         struct ng_bridge_hent *hent;
 787
 788         SLIST_FOREACH(hent, &priv->tab[bucket], next) {
 789                 if (ETHER_EQUAL(hent->host.addr, addr))
 790                         return (&hent->host);
 791         }
 792         return (NULL);
 793 }
 794
 795 /*
 796  * Add a new host entry to the table. This assumes the host doesn't
 797  * already exist in the table. Returns 1 on success, 0 if there
 798  * was a memory allocation failure.
 799  */
 800 static int
 801 ng_bridge_put(priv_p priv, const u_char *addr, int linkNum)
 802 {
 803         const int bucket = HASH(addr, priv->hashMask);
 804         struct ng_bridge_hent *hent;
 805
 806 #ifdef INVARIANTS
 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 %6D exists in table", __func__, addr, ":"));
 811         }
 812 #endif
 813
 814         /* Allocate and initialize new hashtable entry */
 815         MALLOC(hent, struct ng_bridge_hent *,
 816             sizeof(*hent), M_NETGRAPH, M_NOWAIT);
 817         if (hent == NULL)
 818                 return (0);
 819         bcopy(addr, hent->host.addr, ETHER_ADDR_LEN);
 820         hent->host.linkNum = linkNum;
 821         hent->host.staleness = 0;
 822         hent->host.age = 0;
 823
 824         /* Add new element to hash bucket */
 825         SLIST_INSERT_HEAD(&priv->tab[bucket], hent, next);
 826         priv->numHosts++;
 827
 828         /* Resize table if necessary */
 829         ng_bridge_rehash(priv);
 830         return (1);
 831 }
 832
 833 /*
 834  * Resize the hash table. We try to maintain the number of buckets
 835  * such that the load factor is in the range 0.25 to 1.0.
 836  *
 837  * If we can't get the new memory then we silently fail. This is OK
 838  * because things will still work and we'll try again soon anyway.
 839  */
 840 static void
 841 ng_bridge_rehash(priv_p priv)
 842 {
 843         struct ng_bridge_bucket *newTab;
 844         int oldBucket, newBucket;
 845         int newNumBuckets;
 846         u_int newMask;
 847
 848         /* Is table too full or too empty? */
 849         if (priv->numHosts > priv->numBuckets
 850             && (priv->numBuckets << 1) <= MAX_BUCKETS)
 851                 newNumBuckets = priv->numBuckets << 1;
 852         else if (priv->numHosts < (priv->numBuckets >> 2)
 853             && (priv->numBuckets >> 2) >= MIN_BUCKETS)
 854                 newNumBuckets = priv->numBuckets >> 2;
 855         else
 856                 return;
 857         newMask = newNumBuckets - 1;
 858
 859         /* Allocate and initialize new table */
 860         MALLOC(newTab, struct ng_bridge_bucket *,
 861             newNumBuckets * sizeof(*newTab), M_NETGRAPH, M_NOWAIT);
 862         if (newTab == NULL)
 863                 return;
 864         bzero(newTab, newNumBuckets * sizeof(*newTab));
 865
 866         /* Move all entries from old table to new table */
 867         for (oldBucket = 0; oldBucket < priv->numBuckets; oldBucket++) {
 868                 struct ng_bridge_bucket *const oldList = &priv->tab[oldBucket];
 869
 870                 while (!SLIST_EMPTY(oldList)) {
 871                         struct ng_bridge_hent *const hent
 872                             = SLIST_FIRST(oldList);
 873
 874                         SLIST_REMOVE_HEAD(oldList, next);
 875                         newBucket = HASH(hent->host.addr, newMask);
 876                         SLIST_INSERT_HEAD(&newTab[newBucket], hent, next);
 877                 }
 878         }
 879
 880         /* Replace old table with new one */
 881         if (priv->conf.debugLevel >= 3) {
 882                 log(LOG_INFO, "ng_bridge: %s: table size %d -> %d\n",
 883                     ng_bridge_nodename(priv->node),
 884                     priv->numBuckets, newNumBuckets);
 885         }
 886         FREE(priv->tab, M_NETGRAPH);
 887         priv->numBuckets = newNumBuckets;
 888         priv->hashMask = newMask;
 889         priv->tab = newTab;
 890         return;
 891 }
 892
 893 /******************************************************************
 894                     MISC FUNCTIONS
 895 ******************************************************************/
 896
 897 /*
 898  * Remove all hosts associated with a specific link from the hashtable.
 899  * If linkNum == -1, then remove all hosts in the table.
 900  */
 901 static void
 902 ng_bridge_remove_hosts(priv_p priv, int linkNum)
 903 {
 904         int bucket;
 905
 906         for (bucket = 0; bucket < priv->numBuckets; bucket++) {
 907                 struct ng_bridge_hent **hptr = &SLIST_FIRST(&priv->tab[bucket]);
 908
 909                 while (*hptr != NULL) {
 910                         struct ng_bridge_hent *const hent = *hptr;
 911
 912                         if (linkNum == -1 || hent->host.linkNum == linkNum) {
 913                                 *hptr = SLIST_NEXT(hent, next);
 914                                 FREE(hent, M_NETGRAPH);
 915                                 priv->numHosts--;
 916                         } else
 917                                 hptr = &SLIST_NEXT(hent, next);
 918                 }
 919         }
 920 }
 921
 922 /*
 923  * Handle our once-per-second timeout event. We do two things:
 924  * we decrement link->loopCount for those links being muted due to
 925  * a detected loopback condition, and we remove any hosts from
 926  * the hashtable whom we haven't heard from in a long while.
 927  *
 928  * If the node has the NG_INVALID flag set, our job is to kill it.
 929  */
 930 static void
 931 ng_bridge_timeout(void *arg)
 932 {
 933         const node_p node = arg;
 934         const priv_p priv = node->private;
 935         int s, bucket;
 936         int counter = 0;
 937         int linkNum;
 938
 939         /* If node was shut down, this is the final lingering timeout */
 940         s = splnet();
 941         if ((node->flags & NG_INVALID) != 0) {
 942                 FREE(priv, M_NETGRAPH);
 943                 node->private = NULL;
 944                 ng_unref(node);
 945                 splx(s);
 946                 return;
 947         }
 948
 949         /* Register a new timeout, keeping the existing node reference */
 950         callout_reset(&priv->timer, hz, ng_bridge_timeout, node);
 951
 952         /* Update host time counters and remove stale entries */
 953         for (bucket = 0; bucket < priv->numBuckets; bucket++) {
 954                 struct ng_bridge_hent **hptr = &SLIST_FIRST(&priv->tab[bucket]);
 955
 956                 while (*hptr != NULL) {
 957                         struct ng_bridge_hent *const hent = *hptr;
 958
 959                         /* Make sure host's link really exists */
 960                         KASSERT(priv->links[hent->host.linkNum] != NULL,
 961                             ("%s: host %6D on nonexistent link %d\n",
 962                             __func__, hent->host.addr, ":",
 963                             hent->host.linkNum));
 964
 965                         /* Remove hosts we haven't heard from in a while */
 966                         if (++hent->host.staleness >= priv->conf.maxStaleness) {
 967                                 *hptr = SLIST_NEXT(hent, next);
 968                                 FREE(hent, M_NETGRAPH);
 969                                 priv->numHosts--;
 970                         } else {
 971                                 if (hent->host.age < 0xffff)
 972                                         hent->host.age++;
 973                                 hptr = &SLIST_NEXT(hent, next);
 974                                 counter++;
 975                         }
 976                 }
 977         }
 978         KASSERT(priv->numHosts == counter,
 979             ("%s: hosts: %d != %d", __func__, priv->numHosts, counter));
 980
 981         /* Decrease table size if necessary */
 982         ng_bridge_rehash(priv);
 983
 984         /* Decrease loop counter on muted looped back links */
 985         for (counter = linkNum = 0; linkNum < NG_BRIDGE_MAX_LINKS; linkNum++) {
 986                 struct ng_bridge_link *const link = priv->links[linkNum];
 987
 988                 if (link != NULL) {
 989                         if (link->loopCount != 0) {
 990                                 link->loopCount--;
 991                                 if (link->loopCount == 0
 992                                     && priv->conf.debugLevel >= 2) {
 993                                         log(LOG_INFO, "ng_bridge: %s:"
 994                                             " restoring looped back link%d\n",
 995                                             ng_bridge_nodename(node), linkNum);
 996                                 }
 997                         }
 998                         counter++;
 999                 }
1000         }
1001         KASSERT(priv->numLinks == counter,
1002             ("%s: links: %d != %d", __func__, priv->numLinks, counter));
1003
1004         /* Done */
1005         splx(s);
1006 }
1007
1008 /*
1009  * Return node's "name", even if it doesn't have one.
1010  */
1011 static const char *
1012 ng_bridge_nodename(node_p node)
1013 {
1014         static char name[NG_NODELEN+1];
1015
1016         if (node->name != NULL)
1017                 snprintf(name, sizeof(name), "%s", node->name);
1018         else
1019                 snprintf(name, sizeof(name), "[%x]", ng_node2ID(node));
1020         return name;
1021 }
1022