sys/netgraph7/ng_bridge.c

   1 /*
   2  * ng_bridge.c
   3  */
   4
   5 /*-
   6  * Copyright (c) 2000 Whistle Communications, Inc.
   7  * All rights reserved.
   8  *
   9  * Subject to the following obligations and disclaimer of warranty, use and
  10  * redistribution of this software, in source or object code forms, with or
  11  * without modifications are expressly permitted by Whistle Communications;
  12  * provided, however, that:
  13  * 1. Any and all reproductions of the source or object code must include the
  14  *    copyright notice above and the following disclaimer of warranties; and
  15  * 2. No rights are granted, in any manner or form, to use Whistle
  16  *    Communications, Inc. trademarks, including the mark "WHISTLE
  17  *    COMMUNICATIONS" on advertising, endorsements, or otherwise except as
  18  *    such appears in the above copyright notice or in the software.
  19  *
  20  * THIS SOFTWARE IS BEING PROVIDED BY WHISTLE COMMUNICATIONS "AS IS", AND
  21  * TO THE MAXIMUM EXTENT PERMITTED BY LAW, WHISTLE COMMUNICATIONS MAKES NO
  22  * REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED, REGARDING THIS SOFTWARE,
  23  * INCLUDING WITHOUT LIMITATION, ANY AND ALL IMPLIED WARRANTIES OF
  24  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT.
  25  * WHISTLE COMMUNICATIONS DOES NOT WARRANT, GUARANTEE, OR MAKE ANY
  26  * REPRESENTATIONS REGARDING THE USE OF, OR THE RESULTS OF THE USE OF THIS
  27  * SOFTWARE IN TERMS OF ITS CORRECTNESS, ACCURACY, RELIABILITY OR OTHERWISE.
  28  * IN NO EVENT SHALL WHISTLE COMMUNICATIONS BE LIABLE FOR ANY DAMAGES
  29  * RESULTING FROM OR ARISING OUT OF ANY USE OF THIS SOFTWARE, INCLUDING
  30  * WITHOUT LIMITATION, ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
  31  * PUNITIVE, OR CONSEQUENTIAL DAMAGES, PROCUREMENT OF SUBSTITUTE GOODS OR
  32  * SERVICES, LOSS OF USE, DATA OR PROFITS, HOWEVER CAUSED AND UNDER ANY
  33  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  34  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  35  * THIS SOFTWARE, EVEN IF WHISTLE COMMUNICATIONS IS ADVISED OF THE POSSIBILITY
  36  * OF SUCH DAMAGE.
  37  *
  38  * Author: Archie Cobbs <archie@freebsd.org>
  39  *
  40  * $FreeBSD: src/sys/netgraph/ng_bridge.c,v 1.31 2005/02/09 15:14:44 ru Exp $
  41  * $DragonFly: src/sys/netgraph7/ng_bridge.c,v 1.2 2008/06/26 23:05:35 dillon Exp $
  42  */
  43
  44 /*
  45  * ng_bridge(4) netgraph node type
  46  *
  47  * The node performs standard intelligent Ethernet bridging over
  48  * each of its connected hooks, or links.  A simple loop detection
  49  * algorithm is included which disables a link for priv->conf.loopTimeout
  50  * seconds when a host is seen to have jumped from one link to
  51  * another within priv->conf.minStableAge seconds.
  52  *
  53  * We keep a hashtable that maps Ethernet addresses to host info,
  54  * which is contained in struct ng_bridge_host's. These structures
  55  * tell us on which link the host may be found. A host's entry will
  56  * expire after priv->conf.maxStaleness seconds.
  57  *
  58  * This node is optimzed for stable networks, where machines jump
  59  * from one port to the other only rarely.
  60  */
  61
  62 #include <sys/param.h>
  63 #include <sys/systm.h>
  64 #include <sys/kernel.h>
  65 #include <sys/malloc.h>
  66 #include <sys/mbuf.h>
  67 #include <sys/errno.h>
  68 #include <sys/syslog.h>
  69 #include <sys/socket.h>
  70 #include <sys/ctype.h>
  71
  72 #include <net/if.h>
  73 #include <net/ethernet.h>
  74
  75 #include <netinet/in.h>
  76 #include <netinet/ip_fw.h>
  77
  78 #include "ng_message.h"
  79 #include "netgraph.h"
  80 #include "ng_parse.h"
  81 #include "ng_bridge.h"
  82
  83 #ifdef NG_SEPARATE_MALLOC
  84 MALLOC_DEFINE(M_NETGRAPH_BRIDGE, "netgraph_bridge", "netgraph bridge node ");
  85 #else
  86 #define M_NETGRAPH_BRIDGE M_NETGRAPH
  87 #endif
  88
  89 /* Per-link private data */
  90 struct ng_bridge_link {
  91         hook_p                          hook;           /* netgraph hook */
  92         u_int16_t                       loopCount;      /* loop ignore timer */
  93         struct ng_bridge_link_stats     stats;          /* link stats */
  94 };
  95
  96 /* Per-node private data */
  97 struct ng_bridge_private {
  98         struct ng_bridge_bucket *tab;           /* hash table bucket array */
  99         struct ng_bridge_link   *links[NG_BRIDGE_MAX_LINKS];
 100         struct ng_bridge_config conf;           /* node configuration */
 101         node_p                  node;           /* netgraph node */
 102         u_int                   numHosts;       /* num entries in table */
 103         u_int                   numBuckets;     /* num buckets in table */
 104         u_int                   hashMask;       /* numBuckets - 1 */
 105         int                     numLinks;       /* num connected links */
 106         struct callout          timer;          /* one second periodic timer */
 107 };
 108 typedef struct ng_bridge_private *priv_p;
 109
 110 /* Information about a host, stored in a hash table entry */
 111 struct ng_bridge_hent {
 112         struct ng_bridge_host           host;   /* actual host info */
 113         SLIST_ENTRY(ng_bridge_hent)     next;   /* next entry in bucket */
 114 };
 115
 116 /* Hash table bucket declaration */
 117 SLIST_HEAD(ng_bridge_bucket, ng_bridge_hent);
 118
 119 /* Netgraph node methods */
 120 static ng_constructor_t ng_bridge_constructor;
 121 static ng_rcvmsg_t      ng_bridge_rcvmsg;
 122 static ng_shutdown_t    ng_bridge_shutdown;
 123 static ng_newhook_t     ng_bridge_newhook;
 124 static ng_rcvdata_t     ng_bridge_rcvdata;
 125 static ng_disconnect_t  ng_bridge_disconnect;
 126
 127 /* Other internal functions */
 128 static struct   ng_bridge_host *ng_bridge_get(priv_p priv, const u_char *addr);
 129 static int      ng_bridge_put(priv_p priv, const u_char *addr, int linkNum);
 130 static void     ng_bridge_rehash(priv_p priv);
 131 static void     ng_bridge_remove_hosts(priv_p priv, int linkNum);
 132 static void     ng_bridge_timeout(node_p node, hook_p hook, void *arg1, int arg2);
 133 static const    char *ng_bridge_nodename(node_p node);
 134
 135 /* Ethernet broadcast */
 136 static const u_char ng_bridge_bcast_addr[ETHER_ADDR_LEN] =
 137     { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
 138
 139 /* Store each hook's link number in the private field */
 140 #define LINK_NUM(hook)          (*(u_int16_t *)(&(hook)->private))
 141
 142 /* Compare Ethernet addresses using 32 and 16 bit words instead of bytewise */
 143 #define ETHER_EQUAL(a,b)        (((const u_int32_t *)(a))[0] \
 144                                         == ((const u_int32_t *)(b))[0] \
 145                                     && ((const u_int16_t *)(a))[2] \
 146                                         == ((const u_int16_t *)(b))[2])
 147
 148 /* Minimum and maximum number of hash buckets. Must be a power of two. */
 149 #define MIN_BUCKETS             (1 << 5)        /* 32 */
 150 #define MAX_BUCKETS             (1 << 14)       /* 16384 */
 151
 152 /* Configuration default values */
 153 #define DEFAULT_LOOP_TIMEOUT    60
 154 #define DEFAULT_MAX_STALENESS   (15 * 60)       /* same as ARP timeout */
 155 #define DEFAULT_MIN_STABLE_AGE  1
 156
 157 /******************************************************************
 158                     NETGRAPH PARSE TYPES
 159 ******************************************************************/
 160
 161 /*
 162  * How to determine the length of the table returned by NGM_BRIDGE_GET_TABLE
 163  */
 164 static int
 165 ng_bridge_getTableLength(const struct ng_parse_type *type,
 166         const u_char *start, const u_char *buf)
 167 {
 168         const struct ng_bridge_host_ary *const hary
 169             = (const struct ng_bridge_host_ary *)(buf - sizeof(u_int32_t));
 170
 171         return hary->numHosts;
 172 }
 173
 174 /* Parse type for struct ng_bridge_host_ary */
 175 static const struct ng_parse_struct_field ng_bridge_host_type_fields[]
 176         = NG_BRIDGE_HOST_TYPE_INFO(&ng_parse_enaddr_type);
 177 static const struct ng_parse_type ng_bridge_host_type = {
 178         &ng_parse_struct_type,
 179         &ng_bridge_host_type_fields
 180 };
 181 static const struct ng_parse_array_info ng_bridge_hary_type_info = {
 182         &ng_bridge_host_type,
 183         ng_bridge_getTableLength
 184 };
 185 static const struct ng_parse_type ng_bridge_hary_type = {
 186         &ng_parse_array_type,
 187         &ng_bridge_hary_type_info
 188 };
 189 static const struct ng_parse_struct_field ng_bridge_host_ary_type_fields[]
 190         = NG_BRIDGE_HOST_ARY_TYPE_INFO(&ng_bridge_hary_type);
 191 static const struct ng_parse_type ng_bridge_host_ary_type = {
 192         &ng_parse_struct_type,
 193         &ng_bridge_host_ary_type_fields
 194 };
 195
 196 /* Parse type for struct ng_bridge_config */
 197 static const struct ng_parse_fixedarray_info ng_bridge_ipfwary_type_info = {
 198         &ng_parse_uint8_type,
 199         NG_BRIDGE_MAX_LINKS
 200 };
 201 static const struct ng_parse_type ng_bridge_ipfwary_type = {
 202         &ng_parse_fixedarray_type,
 203         &ng_bridge_ipfwary_type_info
 204 };
 205 static const struct ng_parse_struct_field ng_bridge_config_type_fields[]
 206         = NG_BRIDGE_CONFIG_TYPE_INFO(&ng_bridge_ipfwary_type);
 207 static const struct ng_parse_type ng_bridge_config_type = {
 208         &ng_parse_struct_type,
 209         &ng_bridge_config_type_fields
 210 };
 211
 212 /* Parse type for struct ng_bridge_link_stat */
 213 static const struct ng_parse_struct_field ng_bridge_stats_type_fields[]
 214         = NG_BRIDGE_STATS_TYPE_INFO;
 215 static const struct ng_parse_type ng_bridge_stats_type = {
 216         &ng_parse_struct_type,
 217         &ng_bridge_stats_type_fields
 218 };
 219
 220 /* List of commands and how to convert arguments to/from ASCII */
 221 static const struct ng_cmdlist ng_bridge_cmdlist[] = {
 222         {
 223           NGM_BRIDGE_COOKIE,
 224           NGM_BRIDGE_SET_CONFIG,
 225           "setconfig",
 226           &ng_bridge_config_type,
 227           NULL
 228         },
 229         {
 230           NGM_BRIDGE_COOKIE,
 231           NGM_BRIDGE_GET_CONFIG,
 232           "getconfig",
 233           NULL,
 234           &ng_bridge_config_type
 235         },
 236         {
 237           NGM_BRIDGE_COOKIE,
 238           NGM_BRIDGE_RESET,
 239           "reset",
 240           NULL,
 241           NULL
 242         },
 243         {
 244           NGM_BRIDGE_COOKIE,
 245           NGM_BRIDGE_GET_STATS,
 246           "getstats",
 247           &ng_parse_uint32_type,
 248           &ng_bridge_stats_type
 249         },
 250         {
 251           NGM_BRIDGE_COOKIE,
 252           NGM_BRIDGE_CLR_STATS,
 253           "clrstats",
 254           &ng_parse_uint32_type,
 255           NULL
 256         },
 257         {
 258           NGM_BRIDGE_COOKIE,
 259           NGM_BRIDGE_GETCLR_STATS,
 260           "getclrstats",
 261           &ng_parse_uint32_type,
 262           &ng_bridge_stats_type
 263         },
 264         {
 265           NGM_BRIDGE_COOKIE,
 266           NGM_BRIDGE_GET_TABLE,
 267           "gettable",
 268           NULL,
 269           &ng_bridge_host_ary_type
 270         },
 271         { 0 }
 272 };
 273
 274 /* Node type descriptor */
 275 static struct ng_type ng_bridge_typestruct = {
 276         .version =      NG_ABI_VERSION,
 277         .name =         NG_BRIDGE_NODE_TYPE,
 278         .constructor =  ng_bridge_constructor,
 279         .rcvmsg =       ng_bridge_rcvmsg,
 280         .shutdown =     ng_bridge_shutdown,
 281         .newhook =      ng_bridge_newhook,
 282         .rcvdata =      ng_bridge_rcvdata,
 283         .disconnect =   ng_bridge_disconnect,
 284         .cmdlist =      ng_bridge_cmdlist,
 285 };
 286 NETGRAPH_INIT(bridge, &ng_bridge_typestruct);
 287
 288 /******************************************************************
 289                     NETGRAPH NODE METHODS
 290 ******************************************************************/
 291
 292 /*
 293  * Node constructor
 294  */
 295 static int
 296 ng_bridge_constructor(node_p node)
 297 {
 298         priv_p priv;
 299
 300         /* Allocate and initialize private info */
 301         MALLOC(priv, priv_p, sizeof(*priv), M_NETGRAPH_BRIDGE, 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         MALLOC(priv->tab, struct ng_bridge_bucket *,
 308             MIN_BUCKETS * sizeof(*priv->tab), M_NETGRAPH_BRIDGE, M_WAITOK | M_NULLOK | M_ZERO);
 309         if (priv->tab == NULL) {
 310                 FREE(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                 MALLOC(priv->links[linkNum], struct ng_bridge_link *,
 363                     sizeof(*priv->links[linkNum]), M_NETGRAPH_BRIDGE, M_WAITOK | M_NULLOK | M_ZERO);
 364                 if (priv->links[linkNum] == NULL)
 365                         return (ENOMEM);
 366                 priv->links[linkNum]->hook = hook;
 367                 NG_HOOK_SET_PRIVATE(hook, (void *)linkNum);
 368                 priv->numLinks++;
 369                 return (0);
 370         }
 371
 372         /* Unknown hook name */
 373         return (EINVAL);
 374 }
 375
 376 /*
 377  * Receive a control message
 378  */
 379 static int
 380 ng_bridge_rcvmsg(node_p node, item_p item, hook_p lasthook)
 381 {
 382         const priv_p priv = NG_NODE_PRIVATE(node);
 383         struct ng_mesg *resp = NULL;
 384         int error = 0;
 385         struct ng_mesg *msg;
 386
 387         NGI_GET_MSG(item, msg);
 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_WAITOK | M_NULLOK);
 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_WAITOK | M_NULLOK);
 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_WAITOK | M_NULLOK);
 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         NG_RESPOND_MSG(error, node, item, resp);
 507         NG_FREE_MSG(msg);
 508         return (error);
 509 }
 510
 511 /*
 512  * Receive data on a hook
 513  */
 514 static int
 515 ng_bridge_rcvdata(hook_p hook, item_p item)
 516 {
 517         const node_p node = NG_HOOK_NODE(hook);
 518         const priv_p priv = NG_NODE_PRIVATE(node);
 519         struct ng_bridge_host *host;
 520         struct ng_bridge_link *link;
 521         struct ether_header *eh;
 522         int error = 0, linkNum, linksSeen;
 523         int manycast;
 524         struct mbuf *m;
 525         struct ng_bridge_link *firstLink;
 526
 527         NGI_GET_M(item, m);
 528         /* Get link number */
 529         linkNum = (intptr_t)NG_HOOK_PRIVATE(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_ITEM(item);
 539                 NG_FREE_M(m);
 540                 return (EINVAL);
 541         }
 542         if (m->m_len < ETHER_HDR_LEN && !(m = m_pullup(m, ETHER_HDR_LEN))) {
 543                 link->stats.memoryFailures++;
 544                 NG_FREE_ITEM(item);
 545                 return (ENOBUFS);
 546         }
 547         eh = mtod(m, struct ether_header *);
 548         if ((eh->ether_shost[0] & 1) != 0) {
 549                 link->stats.recvInvalid++;
 550                 NG_FREE_ITEM(item);
 551                 NG_FREE_M(m);
 552                 return (EINVAL);
 553         }
 554
 555         /* Is link disabled due to a loopback condition? */
 556         if (link->loopCount != 0) {
 557                 link->stats.loopDrops++;
 558                 NG_FREE_ITEM(item);
 559                 NG_FREE_M(m);
 560                 return (ELOOP);         /* XXX is this an appropriate error? */
 561         }
 562
 563         /* Update stats */
 564         link->stats.recvPackets++;
 565         link->stats.recvOctets += m->m_pkthdr.len;
 566         if ((manycast = (eh->ether_dhost[0] & 1)) != 0) {
 567                 if (ETHER_EQUAL(eh->ether_dhost, ng_bridge_bcast_addr)) {
 568                         link->stats.recvBroadcasts++;
 569                         manycast = 2;
 570                 } else
 571                         link->stats.recvMulticasts++;
 572         }
 573
 574         /* Look up packet's source Ethernet address in hashtable */
 575         if ((host = ng_bridge_get(priv, eh->ether_shost)) != NULL) {
 576
 577                 /* Update time since last heard from this host */
 578                 host->staleness = 0;
 579
 580                 /* Did host jump to a different link? */
 581                 if (host->linkNum != linkNum) {
 582
 583                         /*
 584                          * If the host's old link was recently established
 585                          * on the old link and it's already jumped to a new
 586                          * link, declare a loopback condition.
 587                          */
 588                         if (host->age < priv->conf.minStableAge) {
 589
 590                                 /* Log the problem */
 591                                 if (priv->conf.debugLevel >= 2) {
 592                                         struct ifnet *ifp = m->m_pkthdr.rcvif;
 593                                         char suffix[32];
 594
 595                                         if (ifp != NULL)
 596                                                 snprintf(suffix, sizeof(suffix),
 597                                                     " (%s)", ifp->if_xname);
 598                                         else
 599                                                 *suffix = '\0';
 600                                         log(LOG_WARNING, "ng_bridge: %s:"
 601                                             " loopback detected on %s%s\n",
 602                                             ng_bridge_nodename(node),
 603                                             NG_HOOK_NAME(hook), suffix);
 604                                 }
 605
 606                                 /* Mark link as linka non grata */
 607                                 link->loopCount = priv->conf.loopTimeout;
 608                                 link->stats.loopDetects++;
 609
 610                                 /* Forget all hosts on this link */
 611                                 ng_bridge_remove_hosts(priv, linkNum);
 612
 613                                 /* Drop packet */
 614                                 link->stats.loopDrops++;
 615                                 NG_FREE_ITEM(item);
 616                                 NG_FREE_M(m);
 617                                 return (ELOOP);         /* XXX appropriate? */
 618                         }
 619
 620                         /* Move host over to new link */
 621                         host->linkNum = linkNum;
 622                         host->age = 0;
 623                 }
 624         } else {
 625                 if (!ng_bridge_put(priv, eh->ether_shost, linkNum)) {
 626                         link->stats.memoryFailures++;
 627                         NG_FREE_ITEM(item);
 628                         NG_FREE_M(m);
 629                         return (ENOMEM);
 630                 }
 631         }
 632
 633         /* Run packet through ipfw processing, if enabled */
 634 #if 0
 635         if (priv->conf.ipfw[linkNum] && fw_enable && ip_fw_chk_ptr != NULL) {
 636                 /* XXX not implemented yet */
 637         }
 638 #endif
 639
 640         /*
 641          * If unicast and destination host known, deliver to host's link,
 642          * unless it is the same link as the packet came in on.
 643          */
 644         if (!manycast) {
 645
 646                 /* Determine packet destination link */
 647                 if ((host = ng_bridge_get(priv, eh->ether_dhost)) != NULL) {
 648                         struct ng_bridge_link *const destLink
 649                             = priv->links[host->linkNum];
 650
 651                         /* If destination same as incoming link, do nothing */
 652                         KASSERT(destLink != NULL,
 653                             ("%s: link%d null", __func__, host->linkNum));
 654                         if (destLink == link) {
 655                                 NG_FREE_ITEM(item);
 656                                 NG_FREE_M(m);
 657                                 return (0);
 658                         }
 659
 660                         /* Deliver packet out the destination link */
 661                         destLink->stats.xmitPackets++;
 662                         destLink->stats.xmitOctets += m->m_pkthdr.len;
 663                         NG_FWD_NEW_DATA(error, item, destLink->hook, m);
 664                         return (error);
 665                 }
 666
 667                 /* Destination host is not known */
 668                 link->stats.recvUnknown++;
 669         }
 670
 671         /* Distribute unknown, multicast, broadcast pkts to all other links */
 672         firstLink = NULL;
 673         for (linkNum = linksSeen = 0; linksSeen <= priv->numLinks; linkNum++) {
 674                 struct ng_bridge_link *destLink;
 675                 struct mbuf *m2 = NULL;
 676
 677                 /*
 678                  * If we have checked all the links then now
 679                  * send the original on its reserved link
 680                  */
 681                 if (linksSeen == priv->numLinks) {
 682                         /* If we never saw a good link, leave. */
 683                         if (firstLink == NULL) {
 684                                 NG_FREE_ITEM(item);
 685                                 NG_FREE_M(m);
 686                                 return (0);
 687                         }
 688                         destLink = firstLink;
 689                 } else {
 690                         destLink = priv->links[linkNum];
 691                         if (destLink != NULL)
 692                                 linksSeen++;
 693                         /* Skip incoming link and disconnected links */
 694                         if (destLink == NULL || destLink == link) {
 695                                 continue;
 696                         }
 697                         if (firstLink == NULL) {
 698                                 /*
 699                                  * This is the first usable link we have found.
 700                                  * Reserve it for the originals.
 701                                  * If we never find another we save a copy.
 702                                  */
 703                                 firstLink = destLink;
 704                                 continue;
 705                         }
 706
 707                         /*
 708                          * It's usable link but not the reserved (first) one.
 709                          * Copy mbuf info for sending.
 710                          */
 711                         m2 = m_dup(m, MB_DONTWAIT);     /* XXX m_copypacket() */
 712                         if (m2 == NULL) {
 713                                 link->stats.memoryFailures++;
 714                                 NG_FREE_ITEM(item);
 715                                 NG_FREE_M(m);
 716                                 return (ENOBUFS);
 717                         }
 718                 }
 719
 720                 /* Update stats */
 721                 destLink->stats.xmitPackets++;
 722                 destLink->stats.xmitOctets += m->m_pkthdr.len;
 723                 switch (manycast) {
 724                 case 0:                                 /* unicast */
 725                         break;
 726                 case 1:                                 /* multicast */
 727                         destLink->stats.xmitMulticasts++;
 728                         break;
 729                 case 2:                                 /* broadcast */
 730                         destLink->stats.xmitBroadcasts++;
 731                         break;
 732                 }
 733
 734                 /* Send packet */
 735                 if (destLink == firstLink) {
 736                         /*
 737                          * If we've sent all the others, send the original
 738                          * on the first link we found.
 739                          */
 740                         NG_FWD_NEW_DATA(error, item, destLink->hook, m);
 741                         break; /* always done last - not really needed. */
 742                 } else {
 743                         NG_SEND_DATA_ONLY(error, destLink->hook, m2);
 744                 }
 745         }
 746         return (error);
 747 }
 748
 749 /*
 750  * Shutdown node
 751  */
 752 static int
 753 ng_bridge_shutdown(node_p node)
 754 {
 755         const priv_p priv = NG_NODE_PRIVATE(node);
 756
 757         /*
 758          * Shut down everything including the timer.  Even if the
 759          * callout has already been dequeued and is about to be
 760          * run, ng_bridge_timeout() won't be fired as the node
 761          * is already marked NGF_INVALID, so we're safe to free
 762          * the node now.
 763          */
 764         KASSERT(priv->numLinks == 0 && priv->numHosts == 0,
 765             ("%s: numLinks=%d numHosts=%d",
 766             __func__, priv->numLinks, priv->numHosts));
 767         ng_uncallout(&priv->timer, node);
 768         NG_NODE_SET_PRIVATE(node, NULL);
 769         NG_NODE_UNREF(node);
 770         FREE(priv->tab, M_NETGRAPH_BRIDGE);
 771         FREE(priv, M_NETGRAPH_BRIDGE);
 772         return (0);
 773 }
 774
 775 /*
 776  * Hook disconnection.
 777  */
 778 static int
 779 ng_bridge_disconnect(hook_p hook)
 780 {
 781         const priv_p priv = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
 782         int linkNum;
 783
 784         /* Get link number */
 785         linkNum = (intptr_t)NG_HOOK_PRIVATE(hook);
 786         KASSERT(linkNum >= 0 && linkNum < NG_BRIDGE_MAX_LINKS,
 787             ("%s: linkNum=%u", __func__, linkNum));
 788
 789         /* Remove all hosts associated with this link */
 790         ng_bridge_remove_hosts(priv, linkNum);
 791
 792         /* Free associated link information */
 793         KASSERT(priv->links[linkNum] != NULL, ("%s: no link", __func__));
 794         FREE(priv->links[linkNum], M_NETGRAPH_BRIDGE);
 795         priv->links[linkNum] = NULL;
 796         priv->numLinks--;
 797
 798         /* If no more hooks, go away */
 799         if ((NG_NODE_NUMHOOKS(NG_HOOK_NODE(hook)) == 0)
 800         && (NG_NODE_IS_VALID(NG_HOOK_NODE(hook)))) {
 801                 ng_rmnode_self(NG_HOOK_NODE(hook));
 802         }
 803         return (0);
 804 }
 805
 806 /******************************************************************
 807                     HASH TABLE FUNCTIONS
 808 ******************************************************************/
 809
 810 /*
 811  * Hash algorithm
 812  */
 813 #define HASH(addr,mask)         ( (((const u_int16_t *)(addr))[0]       \
 814                                  ^ ((const u_int16_t *)(addr))[1]       \
 815                                  ^ ((const u_int16_t *)(addr))[2]) & (mask) )
 816
 817 /*
 818  * Find a host entry in the table.
 819  */
 820 static struct ng_bridge_host *
 821 ng_bridge_get(priv_p priv, const u_char *addr)
 822 {
 823         const int bucket = HASH(addr, priv->hashMask);
 824         struct ng_bridge_hent *hent;
 825
 826         SLIST_FOREACH(hent, &priv->tab[bucket], next) {
 827                 if (ETHER_EQUAL(hent->host.addr, addr))
 828                         return (&hent->host);
 829         }
 830         return (NULL);
 831 }
 832
 833 /*
 834  * Add a new host entry to the table. This assumes the host doesn't
 835  * already exist in the table. Returns 1 on success, 0 if there
 836  * was a memory allocation failure.
 837  */
 838 static int
 839 ng_bridge_put(priv_p priv, const u_char *addr, int linkNum)
 840 {
 841         const int bucket = HASH(addr, priv->hashMask);
 842         struct ng_bridge_hent *hent;
 843
 844 #ifdef INVARIANTS
 845         /* Assert that entry does not already exist in hashtable */
 846         SLIST_FOREACH(hent, &priv->tab[bucket], next) {
 847                 KASSERT(!ETHER_EQUAL(hent->host.addr, addr),
 848                     ("%s: entry %6D exists in table", __func__, addr, ":"));
 849         }
 850 #endif
 851
 852         /* Allocate and initialize new hashtable entry */
 853         MALLOC(hent, struct ng_bridge_hent *,
 854             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         MALLOC(newTab, struct ng_bridge_bucket *,
 899             newNumBuckets * sizeof(*newTab), M_NETGRAPH_BRIDGE, 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         FREE(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                                 FREE(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\n",
 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                                 FREE(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