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  */
  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 <netgraph7/ng_message.h>
  78 #include <netgraph7/netgraph.h>
  79 #include <netgraph7/ng_parse.h>
  80 #include "ng_bridge.h"
  81
  82 #ifdef NG_SEPARATE_MALLOC
  83 MALLOC_DEFINE(M_NETGRAPH_BRIDGE, "netgraph_bridge", "netgraph bridge node ");
  84 #else
  85 #define M_NETGRAPH_BRIDGE M_NETGRAPH
  86 #endif
  87
  88 /* Per-link private data */
  89 struct ng_bridge_link {
  90         hook_p                          hook;           /* netgraph hook */
  91         u_int16_t                       loopCount;      /* loop ignore timer */
  92         struct ng_bridge_link_stats     stats;          /* link stats */
  93 };
  94
  95 /* Per-node private data */
  96 struct ng_bridge_private {
  97         struct ng_bridge_bucket *tab;           /* hash table bucket array */
  98         struct ng_bridge_link   *links[NG_BRIDGE_MAX_LINKS];
  99         struct ng_bridge_config conf;           /* node configuration */
 100         node_p                  node;           /* netgraph node */
 101         u_int                   numHosts;       /* num entries in table */
 102         u_int                   numBuckets;     /* num buckets in table */
 103         u_int                   hashMask;       /* numBuckets - 1 */
 104         int                     numLinks;       /* num connected links */
 105         struct callout          timer;          /* one second periodic timer */
 106 };
 107 typedef struct ng_bridge_private *priv_p;
 108
 109 /* Information about a host, stored in a hash table entry */
 110 struct ng_bridge_hent {
 111         struct ng_bridge_host           host;   /* actual host info */
 112         SLIST_ENTRY(ng_bridge_hent)     next;   /* next entry in bucket */
 113 };
 114
 115 /* Hash table bucket declaration */
 116 SLIST_HEAD(ng_bridge_bucket, ng_bridge_hent);
 117
 118 /* Netgraph node methods */
 119 static ng_constructor_t ng_bridge_constructor;
 120 static ng_rcvmsg_t      ng_bridge_rcvmsg;
 121 static ng_shutdown_t    ng_bridge_shutdown;
 122 static ng_newhook_t     ng_bridge_newhook;
 123 static ng_rcvdata_t     ng_bridge_rcvdata;
 124 static ng_disconnect_t  ng_bridge_disconnect;
 125
 126 /* Other internal functions */
 127 static struct   ng_bridge_host *ng_bridge_get(priv_p priv, const u_char *addr);
 128 static int      ng_bridge_put(priv_p priv, const u_char *addr, int linkNum);
 129 static void     ng_bridge_rehash(priv_p priv);
 130 static void     ng_bridge_remove_hosts(priv_p priv, int linkNum);
 131 static void     ng_bridge_timeout(node_p node, hook_p hook, void *arg1, int arg2);
 132 static const    char *ng_bridge_nodename(node_p node);
 133
 134 /* Ethernet broadcast */
 135 static const u_char ng_bridge_bcast_addr[ETHER_ADDR_LEN] =
 136     { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
 137
 138 /* Store each hook's link number in the private field */
 139 #define LINK_NUM(hook)          (*(u_int16_t *)(&(hook)->private))
 140
 141 /* Compare Ethernet addresses using 32 and 16 bit words instead of bytewise */
 142 #define ETHER_EQUAL(a,b)        (((const u_int32_t *)(a))[0] \
 143                                         == ((const u_int32_t *)(b))[0] \
 144                                     && ((const u_int16_t *)(a))[2] \
 145                                         == ((const u_int16_t *)(b))[2])
 146
 147 /* Minimum and maximum number of hash buckets. Must be a power of two. */
 148 #define MIN_BUCKETS             (1 << 5)        /* 32 */
 149 #define MAX_BUCKETS             (1 << 14)       /* 16384 */
 150
 151 /* Configuration default values */
 152 #define DEFAULT_LOOP_TIMEOUT    60
 153 #define DEFAULT_MAX_STALENESS   (15 * 60)       /* same as ARP timeout */
 154 #define DEFAULT_MIN_STABLE_AGE  1
 155
 156 /******************************************************************
 157                     NETGRAPH PARSE TYPES
 158 ******************************************************************/
 159
 160 /*
 161  * How to determine the length of the table returned by NGM_BRIDGE_GET_TABLE
 162  */
 163 static int
 164 ng_bridge_getTableLength(const struct ng_parse_type *type,
 165         const u_char *start, const u_char *buf)
 166 {
 167         const struct ng_bridge_host_ary *const hary
 168             = (const struct ng_bridge_host_ary *)(buf - sizeof(u_int32_t));
 169
 170         return hary->numHosts;
 171 }
 172
 173 /* Parse type for struct ng_bridge_host_ary */
 174 static const struct ng_parse_struct_field ng_bridge_host_type_fields[]
 175         = NG_BRIDGE_HOST_TYPE_INFO(&ng_parse_enaddr_type);
 176 static const struct ng_parse_type ng_bridge_host_type = {
 177         &ng_parse_struct_type,
 178         &ng_bridge_host_type_fields
 179 };
 180 static const struct ng_parse_array_info ng_bridge_hary_type_info = {
 181         &ng_bridge_host_type,
 182         ng_bridge_getTableLength
 183 };
 184 static const struct ng_parse_type ng_bridge_hary_type = {
 185         &ng_parse_array_type,
 186         &ng_bridge_hary_type_info
 187 };
 188 static const struct ng_parse_struct_field ng_bridge_host_ary_type_fields[]
 189         = NG_BRIDGE_HOST_ARY_TYPE_INFO(&ng_bridge_hary_type);
 190 static const struct ng_parse_type ng_bridge_host_ary_type = {
 191         &ng_parse_struct_type,
 192         &ng_bridge_host_ary_type_fields
 193 };
 194
 195 /* Parse type for struct ng_bridge_config */
 196 static const struct ng_parse_fixedarray_info ng_bridge_ipfwary_type_info = {
 197         &ng_parse_uint8_type,
 198         NG_BRIDGE_MAX_LINKS
 199 };
 200 static const struct ng_parse_type ng_bridge_ipfwary_type = {
 201         &ng_parse_fixedarray_type,
 202         &ng_bridge_ipfwary_type_info
 203 };
 204 static const struct ng_parse_struct_field ng_bridge_config_type_fields[]
 205         = NG_BRIDGE_CONFIG_TYPE_INFO(&ng_bridge_ipfwary_type);
 206 static const struct ng_parse_type ng_bridge_config_type = {
 207         &ng_parse_struct_type,
 208         &ng_bridge_config_type_fields
 209 };
 210
 211 /* Parse type for struct ng_bridge_link_stat */
 212 static const struct ng_parse_struct_field ng_bridge_stats_type_fields[]
 213         = NG_BRIDGE_STATS_TYPE_INFO;
 214 static const struct ng_parse_type ng_bridge_stats_type = {
 215         &ng_parse_struct_type,
 216         &ng_bridge_stats_type_fields
 217 };
 218
 219 /* List of commands and how to convert arguments to/from ASCII */
 220 static const struct ng_cmdlist ng_bridge_cmdlist[] = {
 221         {
 222           NGM_BRIDGE_COOKIE,
 223           NGM_BRIDGE_SET_CONFIG,
 224           "setconfig",
 225           &ng_bridge_config_type,
 226           NULL
 227         },
 228         {
 229           NGM_BRIDGE_COOKIE,
 230           NGM_BRIDGE_GET_CONFIG,
 231           "getconfig",
 232           NULL,
 233           &ng_bridge_config_type
 234         },
 235         {
 236           NGM_BRIDGE_COOKIE,
 237           NGM_BRIDGE_RESET,
 238           "reset",
 239           NULL,
 240           NULL
 241         },
 242         {
 243           NGM_BRIDGE_COOKIE,
 244           NGM_BRIDGE_GET_STATS,
 245           "getstats",
 246           &ng_parse_uint32_type,
 247           &ng_bridge_stats_type
 248         },
 249         {
 250           NGM_BRIDGE_COOKIE,
 251           NGM_BRIDGE_CLR_STATS,
 252           "clrstats",
 253           &ng_parse_uint32_type,
 254           NULL
 255         },
 256         {
 257           NGM_BRIDGE_COOKIE,
 258           NGM_BRIDGE_GETCLR_STATS,
 259           "getclrstats",
 260           &ng_parse_uint32_type,
 261           &ng_bridge_stats_type
 262         },
 263         {
 264           NGM_BRIDGE_COOKIE,
 265           NGM_BRIDGE_GET_TABLE,
 266           "gettable",
 267           NULL,
 268           &ng_bridge_host_ary_type
 269         },
 270         { 0 }
 271 };
 272
 273 /* Node type descriptor */
 274 static struct ng_type ng_bridge_typestruct = {
 275         .version =      NG_ABI_VERSION,
 276         .name =         NG_BRIDGE_NODE_TYPE,
 277         .constructor =  ng_bridge_constructor,
 278         .rcvmsg =       ng_bridge_rcvmsg,
 279         .shutdown =     ng_bridge_shutdown,
 280         .newhook =      ng_bridge_newhook,
 281         .rcvdata =      ng_bridge_rcvdata,
 282         .disconnect =   ng_bridge_disconnect,
 283         .cmdlist =      ng_bridge_cmdlist,
 284 };
 285 NETGRAPH_INIT(bridge, &ng_bridge_typestruct);
 286
 287 /******************************************************************
 288                     NETGRAPH NODE METHODS
 289 ******************************************************************/
 290
 291 /*
 292  * Node constructor
 293  */
 294 static int
 295 ng_bridge_constructor(node_p node)
 296 {
 297         priv_p priv;
 298
 299         /* Allocate and initialize private info */
 300         priv = kmalloc(sizeof(*priv), M_NETGRAPH_BRIDGE,
 301                        M_WAITOK | M_NULLOK | M_ZERO);
 302         if (priv == NULL)
 303                 return (ENOMEM);
 304         ng_callout_init(&priv->timer);
 305
 306         /* Allocate and initialize hash table, etc. */
 307         priv->tab = kmalloc(MIN_BUCKETS * sizeof(*priv->tab),
 308                             M_NETGRAPH_BRIDGE, M_WAITOK | M_NULLOK | M_ZERO);
 309         if (priv->tab == NULL) {
 310                 kfree(priv, M_NETGRAPH_BRIDGE);
 311                 return (ENOMEM);
 312         }
 313         priv->numBuckets = MIN_BUCKETS;
 314         priv->hashMask = MIN_BUCKETS - 1;
 315         priv->conf.debugLevel = 1;
 316         priv->conf.loopTimeout = DEFAULT_LOOP_TIMEOUT;
 317         priv->conf.maxStaleness = DEFAULT_MAX_STALENESS;
 318         priv->conf.minStableAge = DEFAULT_MIN_STABLE_AGE;
 319
 320         /*
 321          * This node has all kinds of stuff that could be screwed by SMP.
 322          * Until it gets it's own internal protection, we go through in
 323          * single file. This could hurt a machine bridging beteen two
 324          * GB ethernets so it should be fixed.
 325          * When it's fixed the process SHOULD NOT SLEEP, spinlocks please!
 326          * (and atomic ops )
 327          */
 328         NG_NODE_FORCE_WRITER(node);
 329         NG_NODE_SET_PRIVATE(node, priv);
 330         priv->node = node;
 331
 332         /* Start timer; timer is always running while node is alive */
 333         ng_callout(&priv->timer, node, NULL, hz, ng_bridge_timeout, NULL, 0);
 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 = NG_NODE_PRIVATE(node);
 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                 priv->links[linkNum] = kmalloc(sizeof(*priv->links[linkNum]),
 363                                                M_NETGRAPH_BRIDGE,
 364                                                M_WAITOK | M_NULLOK | M_ZERO);
 365                 if (priv->links[linkNum] == NULL)
 366                         return (ENOMEM);
 367                 priv->links[linkNum]->hook = hook;
 368                 NG_HOOK_SET_PRIVATE(hook, (void *)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, item_p item, hook_p lasthook)
 382 {
 383         const priv_p priv = NG_NODE_PRIVATE(node);
 384         struct ng_mesg *resp = NULL;
 385         int error = 0;
 386         struct ng_mesg *msg;
 387
 388         NGI_GET_MSG(item, msg);
 389         switch (msg->header.typecookie) {
 390         case NGM_BRIDGE_COOKIE:
 391                 switch (msg->header.cmd) {
 392                 case NGM_BRIDGE_GET_CONFIG:
 393                     {
 394                         struct ng_bridge_config *conf;
 395
 396                         NG_MKRESPONSE(resp, msg,
 397                             sizeof(struct ng_bridge_config), M_WAITOK | M_NULLOK);
 398                         if (resp == NULL) {
 399                                 error = ENOMEM;
 400                                 break;
 401                         }
 402                         conf = (struct ng_bridge_config *)resp->data;
 403                         *conf = priv->conf;     /* no sanity checking needed */
 404                         break;
 405                     }
 406                 case NGM_BRIDGE_SET_CONFIG:
 407                     {
 408                         struct ng_bridge_config *conf;
 409                         int i;
 410
 411                         if (msg->header.arglen
 412                             != sizeof(struct ng_bridge_config)) {
 413                                 error = EINVAL;
 414                                 break;
 415                         }
 416                         conf = (struct ng_bridge_config *)msg->data;
 417                         priv->conf = *conf;
 418                         for (i = 0; i < NG_BRIDGE_MAX_LINKS; i++)
 419                                 priv->conf.ipfw[i] = !!priv->conf.ipfw[i];
 420                         break;
 421                     }
 422                 case NGM_BRIDGE_RESET:
 423                     {
 424                         int i;
 425
 426                         /* Flush all entries in the hash table */
 427                         ng_bridge_remove_hosts(priv, -1);
 428
 429                         /* Reset all loop detection counters and stats */
 430                         for (i = 0; i < NG_BRIDGE_MAX_LINKS; i++) {
 431                                 if (priv->links[i] == NULL)
 432                                         continue;
 433                                 priv->links[i]->loopCount = 0;
 434                                 bzero(&priv->links[i]->stats,
 435                                     sizeof(priv->links[i]->stats));
 436                         }
 437                         break;
 438                     }
 439                 case NGM_BRIDGE_GET_STATS:
 440                 case NGM_BRIDGE_CLR_STATS:
 441                 case NGM_BRIDGE_GETCLR_STATS:
 442                     {
 443                         struct ng_bridge_link *link;
 444                         int linkNum;
 445
 446                         /* Get link number */
 447                         if (msg->header.arglen != sizeof(u_int32_t)) {
 448                                 error = EINVAL;
 449                                 break;
 450                         }
 451                         linkNum = *((u_int32_t *)msg->data);
 452                         if (linkNum < 0 || linkNum >= NG_BRIDGE_MAX_LINKS) {
 453                                 error = EINVAL;
 454                                 break;
 455                         }
 456                         if ((link = priv->links[linkNum]) == NULL) {
 457                                 error = ENOTCONN;
 458                                 break;
 459                         }
 460
 461                         /* Get/clear stats */
 462                         if (msg->header.cmd != NGM_BRIDGE_CLR_STATS) {
 463                                 NG_MKRESPONSE(resp, msg,
 464                                     sizeof(link->stats), M_WAITOK | M_NULLOK);
 465                                 if (resp == NULL) {
 466                                         error = ENOMEM;
 467                                         break;
 468                                 }
 469                                 bcopy(&link->stats,
 470                                     resp->data, sizeof(link->stats));
 471                         }
 472                         if (msg->header.cmd != NGM_BRIDGE_GET_STATS)
 473                                 bzero(&link->stats, sizeof(link->stats));
 474                         break;
 475                     }
 476                 case NGM_BRIDGE_GET_TABLE:
 477                     {
 478                         struct ng_bridge_host_ary *ary;
 479                         struct ng_bridge_hent *hent;
 480                         int i = 0, bucket;
 481
 482                         NG_MKRESPONSE(resp, msg, sizeof(*ary)
 483                             + (priv->numHosts * sizeof(*ary->hosts)), M_WAITOK | M_NULLOK);
 484                         if (resp == NULL) {
 485                                 error = ENOMEM;
 486                                 break;
 487                         }
 488                         ary = (struct ng_bridge_host_ary *)resp->data;
 489                         ary->numHosts = priv->numHosts;
 490                         for (bucket = 0; bucket < priv->numBuckets; bucket++) {
 491                                 SLIST_FOREACH(hent, &priv->tab[bucket], next)
 492                                         ary->hosts[i++] = hent->host;
 493                         }
 494                         break;
 495                     }
 496                 default:
 497                         error = EINVAL;
 498                         break;
 499                 }
 500                 break;
 501         default:
 502                 error = EINVAL;
 503                 break;
 504         }
 505
 506         /* Done */
 507         NG_RESPOND_MSG(error, node, item, resp);
 508         NG_FREE_MSG(msg);
 509         return (error);
 510 }
 511
 512 /*
 513  * Receive data on a hook
 514  */
 515 static int
 516 ng_bridge_rcvdata(hook_p hook, item_p item)
 517 {
 518         const node_p node = NG_HOOK_NODE(hook);
 519         const priv_p priv = NG_NODE_PRIVATE(node);
 520         struct ng_bridge_host *host;
 521         struct ng_bridge_link *link;
 522         struct ether_header *eh;
 523         int error = 0, linkNum, linksSeen;
 524         int manycast;
 525         struct mbuf *m;
 526         struct ng_bridge_link *firstLink;
 527
 528         NGI_GET_M(item, m);
 529         /* Get link number */
 530         linkNum = (intptr_t)NG_HOOK_PRIVATE(hook);
 531         KASSERT(linkNum >= 0 && linkNum < NG_BRIDGE_MAX_LINKS,
 532             ("%s: linkNum=%u", __func__, linkNum));
 533         link = priv->links[linkNum];
 534         KASSERT(link != NULL, ("%s: link%d null", __func__, linkNum));
 535
 536         /* Sanity check packet and pull up header */
 537         if (m->m_pkthdr.len < ETHER_HDR_LEN) {
 538                 link->stats.recvRunts++;
 539                 NG_FREE_ITEM(item);
 540                 NG_FREE_M(m);
 541                 return (EINVAL);
 542         }
 543         if (m->m_len < ETHER_HDR_LEN && !(m = m_pullup(m, ETHER_HDR_LEN))) {
 544                 link->stats.memoryFailures++;
 545                 NG_FREE_ITEM(item);
 546                 return (ENOBUFS);
 547         }
 548         eh = mtod(m, struct ether_header *);
 549         if ((eh->ether_shost[0] & 1) != 0) {
 550                 link->stats.recvInvalid++;
 551                 NG_FREE_ITEM(item);
 552                 NG_FREE_M(m);
 553                 return (EINVAL);
 554         }
 555
 556         /* Is link disabled due to a loopback condition? */
 557         if (link->loopCount != 0) {
 558                 link->stats.loopDrops++;
 559                 NG_FREE_ITEM(item);
 560                 NG_FREE_M(m);
 561                 return (ELOOP);         /* XXX is this an appropriate error? */
 562         }
 563
 564         /* Update stats */
 565         link->stats.recvPackets++;
 566         link->stats.recvOctets += m->m_pkthdr.len;
 567         if ((manycast = (eh->ether_dhost[0] & 1)) != 0) {
 568                 if (ETHER_EQUAL(eh->ether_dhost, ng_bridge_bcast_addr)) {
 569                         link->stats.recvBroadcasts++;
 570                         manycast = 2;
 571                 } else
 572                         link->stats.recvMulticasts++;
 573         }
 574
 575         /* Look up packet's source Ethernet address in hashtable */
 576         if ((host = ng_bridge_get(priv, eh->ether_shost)) != NULL) {
 577
 578                 /* Update time since last heard from this host */
 579                 host->staleness = 0;
 580
 581                 /* Did host jump to a different link? */
 582                 if (host->linkNum != linkNum) {
 583
 584                         /*
 585                          * If the host's old link was recently established
 586                          * on the old link and it's already jumped to a new
 587                          * link, declare a loopback condition.
 588                          */
 589                         if (host->age < priv->conf.minStableAge) {
 590
 591                                 /* Log the problem */
 592                                 if (priv->conf.debugLevel >= 2) {
 593                                         struct ifnet *ifp = m->m_pkthdr.rcvif;
 594                                         char suffix[32];
 595
 596                                         if (ifp != NULL)
 597                                                 snprintf(suffix, sizeof(suffix),
 598                                                     " (%s)", ifp->if_xname);
 599                                         else
 600                                                 *suffix = '\0';
 601                                         log(LOG_WARNING, "ng_bridge: %s:"
 602                                             " loopback detected on %s%s\n",
 603                                             ng_bridge_nodename(node),
 604                                             NG_HOOK_NAME(hook), suffix);
 605                                 }
 606
 607                                 /* Mark link as linka non grata */
 608                                 link->loopCount = priv->conf.loopTimeout;
 609                                 link->stats.loopDetects++;
 610
 611                                 /* Forget all hosts on this link */
 612                                 ng_bridge_remove_hosts(priv, linkNum);
 613
 614                                 /* Drop packet */
 615                                 link->stats.loopDrops++;
 616                                 NG_FREE_ITEM(item);
 617                                 NG_FREE_M(m);
 618                                 return (ELOOP);         /* XXX appropriate? */
 619                         }
 620
 621                         /* Move host over to new link */
 622                         host->linkNum = linkNum;
 623                         host->age = 0;
 624                 }
 625         } else {
 626                 if (!ng_bridge_put(priv, eh->ether_shost, linkNum)) {
 627                         link->stats.memoryFailures++;
 628                         NG_FREE_ITEM(item);
 629                         NG_FREE_M(m);
 630                         return (ENOMEM);
 631                 }
 632         }
 633
 634         /* Run packet through ipfw processing, if enabled */
 635 #if 0
 636         if (priv->conf.ipfw[linkNum] && fw_enable && ip_fw_chk_ptr != NULL) {
 637                 /* XXX not implemented yet */
 638         }
 639 #endif
 640
 641         /*
 642          * If unicast and destination host known, deliver to host's link,
 643          * unless it is the same link as the packet came in on.
 644          */
 645         if (!manycast) {
 646
 647                 /* Determine packet destination link */
 648                 if ((host = ng_bridge_get(priv, eh->ether_dhost)) != NULL) {
 649                         struct ng_bridge_link *const destLink
 650                             = priv->links[host->linkNum];
 651
 652                         /* If destination same as incoming link, do nothing */
 653                         KASSERT(destLink != NULL,
 654                             ("%s: link%d null", __func__, host->linkNum));
 655                         if (destLink == link) {
 656                                 NG_FREE_ITEM(item);
 657                                 NG_FREE_M(m);
 658                                 return (0);
 659                         }
 660
 661                         /* Deliver packet out the destination link */
 662                         destLink->stats.xmitPackets++;
 663                         destLink->stats.xmitOctets += m->m_pkthdr.len;
 664                         NG_FWD_NEW_DATA(error, item, destLink->hook, m);
 665                         return (error);
 666                 }
 667
 668                 /* Destination host is not known */
 669                 link->stats.recvUnknown++;
 670         }
 671
 672         /* Distribute unknown, multicast, broadcast pkts to all other links */
 673         firstLink = NULL;
 674         for (linkNum = linksSeen = 0; linksSeen <= priv->numLinks; linkNum++) {
 675                 struct ng_bridge_link *destLink;
 676                 struct mbuf *m2 = NULL;
 677
 678                 /*
 679                  * If we have checked all the links then now
 680                  * send the original on its reserved link
 681                  */
 682                 if (linksSeen == priv->numLinks) {
 683                         /* If we never saw a good link, leave. */
 684                         if (firstLink == NULL) {
 685                                 NG_FREE_ITEM(item);
 686                                 NG_FREE_M(m);
 687                                 return (0);
 688                         }
 689                         destLink = firstLink;
 690                 } else {
 691                         destLink = priv->links[linkNum];
 692                         if (destLink != NULL)
 693                                 linksSeen++;
 694                         /* Skip incoming link and disconnected links */
 695                         if (destLink == NULL || destLink == link) {
 696                                 continue;
 697                         }
 698                         if (firstLink == NULL) {
 699                                 /*
 700                                  * This is the first usable link we have found.
 701                                  * Reserve it for the originals.
 702                                  * If we never find another we save a copy.
 703                                  */
 704                                 firstLink = destLink;
 705                                 continue;
 706                         }
 707
 708                         /*
 709                          * It's usable link but not the reserved (first) one.
 710                          * Copy mbuf info for sending.
 711                          */
 712                         m2 = m_dup(m, MB_DONTWAIT);     /* XXX m_copypacket() */
 713                         if (m2 == NULL) {
 714                                 link->stats.memoryFailures++;
 715                                 NG_FREE_ITEM(item);
 716                                 NG_FREE_M(m);
 717                                 return (ENOBUFS);
 718                         }
 719                 }
 720
 721                 /* Update stats */
 722                 destLink->stats.xmitPackets++;
 723                 destLink->stats.xmitOctets += m->m_pkthdr.len;
 724                 switch (manycast) {
 725                 case 0:                                 /* unicast */
 726                         break;
 727                 case 1:                                 /* multicast */
 728                         destLink->stats.xmitMulticasts++;
 729                         break;
 730                 case 2:                                 /* broadcast */
 731                         destLink->stats.xmitBroadcasts++;
 732                         break;
 733                 }
 734
 735                 /* Send packet */
 736                 if (destLink == firstLink) {
 737                         /*
 738                          * If we've sent all the others, send the original
 739                          * on the first link we found.
 740                          */
 741                         NG_FWD_NEW_DATA(error, item, destLink->hook, m);
 742                         break; /* always done last - not really needed. */
 743                 } else {
 744                         NG_SEND_DATA_ONLY(error, destLink->hook, m2);
 745                 }
 746         }
 747         return (error);
 748 }
 749
 750 /*
 751  * Shutdown node
 752  */
 753 static int
 754 ng_bridge_shutdown(node_p node)
 755 {
 756         const priv_p priv = NG_NODE_PRIVATE(node);
 757
 758         /*
 759          * Shut down everything including the timer.  Even if the
 760          * callout has already been dequeued and is about to be
 761          * run, ng_bridge_timeout() won't be fired as the node
 762          * is already marked NGF_INVALID, so we're safe to free
 763          * the node now.
 764          */
 765         KASSERT(priv->numLinks == 0 && priv->numHosts == 0,
 766             ("%s: numLinks=%d numHosts=%d",
 767             __func__, priv->numLinks, priv->numHosts));
 768         ng_uncallout(&priv->timer, node);
 769         NG_NODE_SET_PRIVATE(node, NULL);
 770         NG_NODE_UNREF(node);
 771         kfree(priv->tab, M_NETGRAPH_BRIDGE);
 772         kfree(priv, M_NETGRAPH_BRIDGE);
 773         return (0);
 774 }
 775
 776 /*
 777  * Hook disconnection.
 778  */
 779 static int
 780 ng_bridge_disconnect(hook_p hook)
 781 {
 782         const priv_p priv = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
 783         int linkNum;
 784
 785         /* Get link number */
 786         linkNum = (intptr_t)NG_HOOK_PRIVATE(hook);
 787         KASSERT(linkNum >= 0 && linkNum < NG_BRIDGE_MAX_LINKS,
 788             ("%s: linkNum=%u", __func__, linkNum));
 789
 790         /* Remove all hosts associated with this link */
 791         ng_bridge_remove_hosts(priv, linkNum);
 792
 793         /* Free associated link information */
 794         KASSERT(priv->links[linkNum] != NULL, ("%s: no link", __func__));
 795         kfree(priv->links[linkNum], M_NETGRAPH_BRIDGE);
 796         priv->links[linkNum] = NULL;
 797         priv->numLinks--;
 798
 799         /* If no more hooks, go away */
 800         if ((NG_NODE_NUMHOOKS(NG_HOOK_NODE(hook)) == 0)
 801         && (NG_NODE_IS_VALID(NG_HOOK_NODE(hook)))) {
 802                 ng_rmnode_self(NG_HOOK_NODE(hook));
 803         }
 804         return (0);
 805 }
 806
 807 /******************************************************************
 808                     HASH TABLE FUNCTIONS
 809 ******************************************************************/
 810
 811 /*
 812  * Hash algorithm
 813  */
 814 #define HASH(addr,mask)         ( (((const u_int16_t *)(addr))[0]       \
 815                                  ^ ((const u_int16_t *)(addr))[1]       \
 816                                  ^ ((const u_int16_t *)(addr))[2]) & (mask) )
 817
 818 /*
 819  * Find a host entry in the table.
 820  */
 821 static struct ng_bridge_host *
 822 ng_bridge_get(priv_p priv, const u_char *addr)
 823 {
 824         const int bucket = HASH(addr, priv->hashMask);
 825         struct ng_bridge_hent *hent;
 826
 827         SLIST_FOREACH(hent, &priv->tab[bucket], next) {
 828                 if (ETHER_EQUAL(hent->host.addr, addr))
 829                         return (&hent->host);
 830         }
 831         return (NULL);
 832 }
 833
 834 /*
 835  * Add a new host entry to the table. This assumes the host doesn't
 836  * already exist in the table. Returns 1 on success, 0 if there
 837  * was a memory allocation failure.
 838  */
 839 static int
 840 ng_bridge_put(priv_p priv, const u_char *addr, int linkNum)
 841 {
 842         const int bucket = HASH(addr, priv->hashMask);
 843         struct ng_bridge_hent *hent;
 844
 845 #ifdef INVARIANTS
 846         /* Assert that entry does not already exist in hashtable */
 847         SLIST_FOREACH(hent, &priv->tab[bucket], next) {
 848                 KASSERT(!ETHER_EQUAL(hent->host.addr, addr),
 849                     ("%s: entry %6D exists in table", __func__, addr, ":"));
 850         }
 851 #endif
 852
 853         /* Allocate and initialize new hashtable entry */
 854         hent = kmalloc(sizeof(*hent), M_NETGRAPH_BRIDGE, M_WAITOK | M_NULLOK);
 855         if (hent == NULL)
 856                 return (0);
 857         bcopy(addr, hent->host.addr, ETHER_ADDR_LEN);
 858         hent->host.linkNum = linkNum;
 859         hent->host.staleness = 0;
 860         hent->host.age = 0;
 861
 862         /* Add new element to hash bucket */
 863         SLIST_INSERT_HEAD(&priv->tab[bucket], hent, next);
 864         priv->numHosts++;
 865
 866         /* Resize table if necessary */
 867         ng_bridge_rehash(priv);
 868         return (1);
 869 }
 870
 871 /*
 872  * Resize the hash table. We try to maintain the number of buckets
 873  * such that the load factor is in the range 0.25 to 1.0.
 874  *
 875  * If we can't get the new memory then we silently fail. This is OK
 876  * because things will still work and we'll try again soon anyway.
 877  */
 878 static void
 879 ng_bridge_rehash(priv_p priv)
 880 {
 881         struct ng_bridge_bucket *newTab;
 882         int oldBucket, newBucket;
 883         int newNumBuckets;
 884         u_int newMask;
 885
 886         /* Is table too full or too empty? */
 887         if (priv->numHosts > priv->numBuckets
 888             && (priv->numBuckets << 1) <= MAX_BUCKETS)
 889                 newNumBuckets = priv->numBuckets << 1;
 890         else if (priv->numHosts < (priv->numBuckets >> 2)
 891             && (priv->numBuckets >> 2) >= MIN_BUCKETS)
 892                 newNumBuckets = priv->numBuckets >> 2;
 893         else
 894                 return;
 895         newMask = newNumBuckets - 1;
 896
 897         /* Allocate and initialize new table */
 898         newTab = kmalloc(newNumBuckets * sizeof(*newTab), M_NETGRAPH_BRIDGE,
 899                          M_NOWAIT | M_ZERO);
 900         if (newTab == NULL)
 901                 return;
 902
 903         /* Move all entries from old table to new table */
 904         for (oldBucket = 0; oldBucket < priv->numBuckets; oldBucket++) {
 905                 struct ng_bridge_bucket *const oldList = &priv->tab[oldBucket];
 906
 907                 while (!SLIST_EMPTY(oldList)) {
 908                         struct ng_bridge_hent *const hent
 909                             = SLIST_FIRST(oldList);
 910
 911                         SLIST_REMOVE_HEAD(oldList, next);
 912                         newBucket = HASH(hent->host.addr, newMask);
 913                         SLIST_INSERT_HEAD(&newTab[newBucket], hent, next);
 914                 }
 915         }
 916
 917         /* Replace old table with new one */
 918         if (priv->conf.debugLevel >= 3) {
 919                 log(LOG_INFO, "ng_bridge: %s: table size %d -> %d\n",
 920                     ng_bridge_nodename(priv->node),
 921                     priv->numBuckets, newNumBuckets);
 922         }
 923         kfree(priv->tab, M_NETGRAPH_BRIDGE);
 924         priv->numBuckets = newNumBuckets;
 925         priv->hashMask = newMask;
 926         priv->tab = newTab;
 927         return;
 928 }
 929
 930 /******************************************************************
 931                     MISC FUNCTIONS
 932 ******************************************************************/
 933
 934 /*
 935  * Remove all hosts associated with a specific link from the hashtable.
 936  * If linkNum == -1, then remove all hosts in the table.
 937  */
 938 static void
 939 ng_bridge_remove_hosts(priv_p priv, int linkNum)
 940 {
 941         int bucket;
 942
 943         for (bucket = 0; bucket < priv->numBuckets; bucket++) {
 944                 struct ng_bridge_hent **hptr = &SLIST_FIRST(&priv->tab[bucket]);
 945
 946                 while (*hptr != NULL) {
 947                         struct ng_bridge_hent *const hent = *hptr;
 948
 949                         if (linkNum == -1 || hent->host.linkNum == linkNum) {
 950                                 *hptr = SLIST_NEXT(hent, next);
 951                                 kfree(hent, M_NETGRAPH_BRIDGE);
 952                                 priv->numHosts--;
 953                         } else
 954                                 hptr = &SLIST_NEXT(hent, next);
 955                 }
 956         }
 957 }
 958
 959 /*
 960  * Handle our once-per-second timeout event. We do two things:
 961  * we decrement link->loopCount for those links being muted due to
 962  * a detected loopback condition, and we remove any hosts from
 963  * the hashtable whom we haven't heard from in a long while.
 964  */
 965 static void
 966 ng_bridge_timeout(node_p node, hook_p hook, void *arg1, int arg2)
 967 {
 968         const priv_p priv = NG_NODE_PRIVATE(node);
 969         int bucket;
 970         int counter = 0;
 971         int linkNum;
 972
 973         /* Update host time counters and remove stale entries */
 974         for (bucket = 0; bucket < priv->numBuckets; bucket++) {
 975                 struct ng_bridge_hent **hptr = &SLIST_FIRST(&priv->tab[bucket]);
 976
 977                 while (*hptr != NULL) {
 978                         struct ng_bridge_hent *const hent = *hptr;
 979
 980                         /* Make sure host's link really exists */
 981                         KASSERT(priv->links[hent->host.linkNum] != NULL,
 982                             ("%s: host %6D on nonexistent link %d",
 983                             __func__, hent->host.addr, ":",
 984                             hent->host.linkNum));
 985
 986                         /* Remove hosts we haven't heard from in a while */
 987                         if (++hent->host.staleness >= priv->conf.maxStaleness) {
 988                                 *hptr = SLIST_NEXT(hent, next);
 989                                 kfree(hent, M_NETGRAPH_BRIDGE);
 990                                 priv->numHosts--;
 991                         } else {
 992                                 if (hent->host.age < 0xffff)
 993                                         hent->host.age++;
 994                                 hptr = &SLIST_NEXT(hent, next);
 995                                 counter++;
 996                         }
 997                 }
 998         }
 999         KASSERT(priv->numHosts == counter,
1000             ("%s: hosts: %d != %d", __func__, priv->numHosts, counter));
1001
1002         /* Decrease table size if necessary */
1003         ng_bridge_rehash(priv);
1004
1005         /* Decrease loop counter on muted looped back links */
1006         for (counter = linkNum = 0; linkNum < NG_BRIDGE_MAX_LINKS; linkNum++) {
1007                 struct ng_bridge_link *const link = priv->links[linkNum];
1008
1009                 if (link != NULL) {
1010                         if (link->loopCount != 0) {
1011                                 link->loopCount--;
1012                                 if (link->loopCount == 0
1013                                     && priv->conf.debugLevel >= 2) {
1014                                         log(LOG_INFO, "ng_bridge: %s:"
1015                                             " restoring looped back link%d\n",
1016                                             ng_bridge_nodename(node), linkNum);
1017                                 }
1018                         }
1019                         counter++;
1020                 }
1021         }
1022         KASSERT(priv->numLinks == counter,
1023             ("%s: links: %d != %d", __func__, priv->numLinks, counter));
1024
1025         /* Register a new timeout, keeping the existing node reference */
1026         ng_callout(&priv->timer, node, NULL, hz, ng_bridge_timeout, NULL, 0);
1027 }
1028
1029 /*
1030  * Return node's "name", even if it doesn't have one.
1031  */
1032 static const char *
1033 ng_bridge_nodename(node_p node)
1034 {
1035         static char name[NG_NODESIZ];
1036
1037         if (NG_NODE_NAME(node) != NULL)
1038                 snprintf(name, sizeof(name), "%s", NG_NODE_NAME(node));
1039         else
1040                 snprintf(name, sizeof(name), "[%x]", ng_node2ID(node));
1041         return name;
1042 }
1043