sys/netgraph/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  * $FreeBSD$
  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/lock.h>
  65 #include <sys/malloc.h>
  66 #include <sys/mbuf.h>
  67 #include <sys/errno.h>
  68 #include <sys/rwlock.h>
  69 #include <sys/syslog.h>
  70 #include <sys/socket.h>
  71 #include <sys/ctype.h>
  72
  73 #include <net/if.h>
  74 #include <net/ethernet.h>
  75 #include <net/vnet.h>
  76
  77 #include <netinet/in.h>
  78 #include <netinet/ip_fw.h>
  79
  80 #include <netgraph/ng_message.h>
  81 #include <netgraph/netgraph.h>
  82 #include <netgraph/ng_parse.h>
  83 #include <netgraph/ng_bridge.h>
  84
  85 #ifdef NG_SEPARATE_MALLOC
  86 MALLOC_DEFINE(M_NETGRAPH_BRIDGE, "netgraph_bridge", "netgraph bridge node");
  87 #else
  88 #define M_NETGRAPH_BRIDGE M_NETGRAPH
  89 #endif
  90
  91 /* Per-link private data */
  92 struct ng_bridge_link {
  93         hook_p                          hook;           /* netgraph hook */
  94         u_int16_t                       loopCount;      /* loop ignore timer */
  95         struct ng_bridge_link_stats     stats;          /* link stats */
  96 };
  97
  98 /* Per-node private data */
  99 struct ng_bridge_private {
 100         struct ng_bridge_bucket *tab;           /* hash table bucket array */
 101         struct ng_bridge_link   *links[NG_BRIDGE_MAX_LINKS];
 102         struct ng_bridge_config conf;           /* node configuration */
 103         node_p                  node;           /* netgraph node */
 104         u_int                   numHosts;       /* num entries in table */
 105         u_int                   numBuckets;     /* num buckets in table */
 106         u_int                   hashMask;       /* numBuckets - 1 */
 107         int                     numLinks;       /* num connected links */
 108         int                     persistent;     /* can exist w/o hooks */
 109         struct callout          timer;          /* one second periodic timer */
 110 };
 111 typedef struct ng_bridge_private *priv_p;
 112
 113 /* Information about a host, stored in a hash table entry */
 114 struct ng_bridge_hent {
 115         struct ng_bridge_host           host;   /* actual host info */
 116         SLIST_ENTRY(ng_bridge_hent)     next;   /* next entry in bucket */
 117 };
 118
 119 /* Hash table bucket declaration */
 120 SLIST_HEAD(ng_bridge_bucket, ng_bridge_hent);
 121
 122 /* Netgraph node methods */
 123 static ng_constructor_t ng_bridge_constructor;
 124 static ng_rcvmsg_t      ng_bridge_rcvmsg;
 125 static ng_shutdown_t    ng_bridge_shutdown;
 126 static ng_newhook_t     ng_bridge_newhook;
 127 static ng_rcvdata_t     ng_bridge_rcvdata;
 128 static ng_disconnect_t  ng_bridge_disconnect;
 129
 130 /* Other internal functions */
 131 static struct   ng_bridge_host *ng_bridge_get(priv_p priv, const u_char *addr);
 132 static int      ng_bridge_put(priv_p priv, const u_char *addr, int linkNum);
 133 static void     ng_bridge_rehash(priv_p priv);
 134 static void     ng_bridge_remove_hosts(priv_p priv, int linkNum);
 135 static void     ng_bridge_timeout(node_p node, hook_p hook, void *arg1, int arg2);
 136 static const    char *ng_bridge_nodename(node_p node);
 137
 138 /* Ethernet broadcast */
 139 static const u_char ng_bridge_bcast_addr[ETHER_ADDR_LEN] =
 140     { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
 141
 142 /* Store each hook's link number in the private field */
 143 #define LINK_NUM(hook)          (*(u_int16_t *)(&(hook)->private))
 144
 145 /* Compare Ethernet addresses using 32 and 16 bit words instead of bytewise */
 146 #define ETHER_EQUAL(a,b)        (((const u_int32_t *)(a))[0] \
 147                                         == ((const u_int32_t *)(b))[0] \
 148                                     && ((const u_int16_t *)(a))[2] \
 149                                         == ((const u_int16_t *)(b))[2])
 150
 151 /* Minimum and maximum number of hash buckets. Must be a power of two. */
 152 #define MIN_BUCKETS             (1 << 5)        /* 32 */
 153 #define MAX_BUCKETS             (1 << 14)       /* 16384 */
 154
 155 /* Configuration default values */
 156 #define DEFAULT_LOOP_TIMEOUT    60
 157 #define DEFAULT_MAX_STALENESS   (15 * 60)       /* same as ARP timeout */
 158 #define DEFAULT_MIN_STABLE_AGE  1
 159
 160 /******************************************************************
 161                     NETGRAPH PARSE TYPES
 162 ******************************************************************/
 163
 164 /*
 165  * How to determine the length of the table returned by NGM_BRIDGE_GET_TABLE
 166  */
 167 static int
 168 ng_bridge_getTableLength(const struct ng_parse_type *type,
 169         const u_char *start, const u_char *buf)
 170 {
 171         const struct ng_bridge_host_ary *const hary
 172             = (const struct ng_bridge_host_ary *)(buf - sizeof(u_int32_t));
 173
 174         return hary->numHosts;
 175 }
 176
 177 /* Parse type for struct ng_bridge_host_ary */
 178 static const struct ng_parse_struct_field ng_bridge_host_type_fields[]
 179         = NG_BRIDGE_HOST_TYPE_INFO(&ng_parse_enaddr_type);
 180 static const struct ng_parse_type ng_bridge_host_type = {
 181         &ng_parse_struct_type,
 182         &ng_bridge_host_type_fields
 183 };
 184 static const struct ng_parse_array_info ng_bridge_hary_type_info = {
 185         &ng_bridge_host_type,
 186         ng_bridge_getTableLength
 187 };
 188 static const struct ng_parse_type ng_bridge_hary_type = {
 189         &ng_parse_array_type,
 190         &ng_bridge_hary_type_info
 191 };
 192 static const struct ng_parse_struct_field ng_bridge_host_ary_type_fields[]
 193         = NG_BRIDGE_HOST_ARY_TYPE_INFO(&ng_bridge_hary_type);
 194 static const struct ng_parse_type ng_bridge_host_ary_type = {
 195         &ng_parse_struct_type,
 196         &ng_bridge_host_ary_type_fields
 197 };
 198
 199 /* Parse type for struct ng_bridge_config */
 200 static const struct ng_parse_fixedarray_info ng_bridge_ipfwary_type_info = {
 201         &ng_parse_uint8_type,
 202         NG_BRIDGE_MAX_LINKS
 203 };
 204 static const struct ng_parse_type ng_bridge_ipfwary_type = {
 205         &ng_parse_fixedarray_type,
 206         &ng_bridge_ipfwary_type_info
 207 };
 208 static const struct ng_parse_struct_field ng_bridge_config_type_fields[]
 209         = NG_BRIDGE_CONFIG_TYPE_INFO(&ng_bridge_ipfwary_type);
 210 static const struct ng_parse_type ng_bridge_config_type = {
 211         &ng_parse_struct_type,
 212         &ng_bridge_config_type_fields
 213 };
 214
 215 /* Parse type for struct ng_bridge_link_stat */
 216 static const struct ng_parse_struct_field ng_bridge_stats_type_fields[]
 217         = NG_BRIDGE_STATS_TYPE_INFO;
 218 static const struct ng_parse_type ng_bridge_stats_type = {
 219         &ng_parse_struct_type,
 220         &ng_bridge_stats_type_fields
 221 };
 222
 223 /* List of commands and how to convert arguments to/from ASCII */
 224 static const struct ng_cmdlist ng_bridge_cmdlist[] = {
 225         {
 226           NGM_BRIDGE_COOKIE,
 227           NGM_BRIDGE_SET_CONFIG,
 228           "setconfig",
 229           &ng_bridge_config_type,
 230           NULL
 231         },
 232         {
 233           NGM_BRIDGE_COOKIE,
 234           NGM_BRIDGE_GET_CONFIG,
 235           "getconfig",
 236           NULL,
 237           &ng_bridge_config_type
 238         },
 239         {
 240           NGM_BRIDGE_COOKIE,
 241           NGM_BRIDGE_RESET,
 242           "reset",
 243           NULL,
 244           NULL
 245         },
 246         {
 247           NGM_BRIDGE_COOKIE,
 248           NGM_BRIDGE_GET_STATS,
 249           "getstats",
 250           &ng_parse_uint32_type,
 251           &ng_bridge_stats_type
 252         },
 253         {
 254           NGM_BRIDGE_COOKIE,
 255           NGM_BRIDGE_CLR_STATS,
 256           "clrstats",
 257           &ng_parse_uint32_type,
 258           NULL
 259         },
 260         {
 261           NGM_BRIDGE_COOKIE,
 262           NGM_BRIDGE_GETCLR_STATS,
 263           "getclrstats",
 264           &ng_parse_uint32_type,
 265           &ng_bridge_stats_type
 266         },
 267         {
 268           NGM_BRIDGE_COOKIE,
 269           NGM_BRIDGE_GET_TABLE,
 270           "gettable",
 271           NULL,
 272           &ng_bridge_host_ary_type
 273         },
 274         {
 275           NGM_BRIDGE_COOKIE,
 276           NGM_BRIDGE_SET_PERSISTENT,
 277           "setpersistent",
 278           NULL,
 279           NULL
 280         },
 281         { 0 }
 282 };
 283
 284 /* Node type descriptor */
 285 static struct ng_type ng_bridge_typestruct = {
 286         .version =      NG_ABI_VERSION,
 287         .name =         NG_BRIDGE_NODE_TYPE,
 288         .constructor =  ng_bridge_constructor,
 289         .rcvmsg =       ng_bridge_rcvmsg,
 290         .shutdown =     ng_bridge_shutdown,
 291         .newhook =      ng_bridge_newhook,
 292         .rcvdata =      ng_bridge_rcvdata,
 293         .disconnect =   ng_bridge_disconnect,
 294         .cmdlist =      ng_bridge_cmdlist,
 295 };
 296 NETGRAPH_INIT(bridge, &ng_bridge_typestruct);
 297
 298 /******************************************************************
 299                     NETGRAPH NODE METHODS
 300 ******************************************************************/
 301
 302 /*
 303  * Node constructor
 304  */
 305 static int
 306 ng_bridge_constructor(node_p node)
 307 {
 308         priv_p priv;
 309
 310         /* Allocate and initialize private info */
 311         priv = malloc(sizeof(*priv), M_NETGRAPH_BRIDGE, M_NOWAIT | M_ZERO);
 312         if (priv == NULL)
 313                 return (ENOMEM);
 314         ng_callout_init(&priv->timer);
 315
 316         /* Allocate and initialize hash table, etc. */
 317         priv->tab = malloc(MIN_BUCKETS * sizeof(*priv->tab),
 318             M_NETGRAPH_BRIDGE, M_NOWAIT | M_ZERO);
 319         if (priv->tab == NULL) {
 320                 free(priv, M_NETGRAPH_BRIDGE);
 321                 return (ENOMEM);
 322         }
 323         priv->numBuckets = MIN_BUCKETS;
 324         priv->hashMask = MIN_BUCKETS - 1;
 325         priv->conf.debugLevel = 1;
 326         priv->conf.loopTimeout = DEFAULT_LOOP_TIMEOUT;
 327         priv->conf.maxStaleness = DEFAULT_MAX_STALENESS;
 328         priv->conf.minStableAge = DEFAULT_MIN_STABLE_AGE;
 329
 330         /*
 331          * This node has all kinds of stuff that could be screwed by SMP.
 332          * Until it gets it's own internal protection, we go through in
 333          * single file. This could hurt a machine bridging beteen two
 334          * GB ethernets so it should be fixed.
 335          * When it's fixed the process SHOULD NOT SLEEP, spinlocks please!
 336          * (and atomic ops )
 337          */
 338         NG_NODE_FORCE_WRITER(node);
 339         NG_NODE_SET_PRIVATE(node, priv);
 340         priv->node = node;
 341
 342         /* Start timer; timer is always running while node is alive */
 343         ng_callout(&priv->timer, node, NULL, hz, ng_bridge_timeout, NULL, 0);
 344
 345         /* Done */
 346         return (0);
 347 }
 348
 349 /*
 350  * Method for attaching a new hook
 351  */
 352 static  int
 353 ng_bridge_newhook(node_p node, hook_p hook, const char *name)
 354 {
 355         const priv_p priv = NG_NODE_PRIVATE(node);
 356
 357         /* Check for a link hook */
 358         if (strncmp(name, NG_BRIDGE_HOOK_LINK_PREFIX,
 359             strlen(NG_BRIDGE_HOOK_LINK_PREFIX)) == 0) {
 360                 const char *cp;
 361                 char *eptr;
 362                 u_long linkNum;
 363
 364                 cp = name + strlen(NG_BRIDGE_HOOK_LINK_PREFIX);
 365                 if (!isdigit(*cp) || (cp[0] == '0' && cp[1] != '\0'))
 366                         return (EINVAL);
 367                 linkNum = strtoul(cp, &eptr, 10);
 368                 if (*eptr != '\0' || linkNum >= NG_BRIDGE_MAX_LINKS)
 369                         return (EINVAL);
 370                 if (priv->links[linkNum] != NULL)
 371                         return (EISCONN);
 372                 priv->links[linkNum] = malloc(sizeof(*priv->links[linkNum]),
 373                     M_NETGRAPH_BRIDGE, M_NOWAIT|M_ZERO);
 374                 if (priv->links[linkNum] == NULL)
 375                         return (ENOMEM);
 376                 priv->links[linkNum]->hook = hook;
 377                 NG_HOOK_SET_PRIVATE(hook, (void *)linkNum);
 378                 priv->numLinks++;
 379                 return (0);
 380         }
 381
 382         /* Unknown hook name */
 383         return (EINVAL);
 384 }
 385
 386 /*
 387  * Receive a control message
 388  */
 389 static int
 390 ng_bridge_rcvmsg(node_p node, item_p item, hook_p lasthook)
 391 {
 392         const priv_p priv = NG_NODE_PRIVATE(node);
 393         struct ng_mesg *resp = NULL;
 394         int error = 0;
 395         struct ng_mesg *msg;
 396
 397         NGI_GET_MSG(item, msg);
 398         switch (msg->header.typecookie) {
 399         case NGM_BRIDGE_COOKIE:
 400                 switch (msg->header.cmd) {
 401                 case NGM_BRIDGE_GET_CONFIG:
 402                     {
 403                         struct ng_bridge_config *conf;
 404
 405                         NG_MKRESPONSE(resp, msg,
 406                             sizeof(struct ng_bridge_config), M_NOWAIT);
 407                         if (resp == NULL) {
 408                                 error = ENOMEM;
 409                                 break;
 410                         }
 411                         conf = (struct ng_bridge_config *)resp->data;
 412                         *conf = priv->conf;     /* no sanity checking needed */
 413                         break;
 414                     }
 415                 case NGM_BRIDGE_SET_CONFIG:
 416                     {
 417                         struct ng_bridge_config *conf;
 418                         int i;
 419
 420                         if (msg->header.arglen
 421                             != sizeof(struct ng_bridge_config)) {
 422                                 error = EINVAL;
 423                                 break;
 424                         }
 425                         conf = (struct ng_bridge_config *)msg->data;
 426                         priv->conf = *conf;
 427                         for (i = 0; i < NG_BRIDGE_MAX_LINKS; i++)
 428                                 priv->conf.ipfw[i] = !!priv->conf.ipfw[i];
 429                         break;
 430                     }
 431                 case NGM_BRIDGE_RESET:
 432                     {
 433                         int i;
 434
 435                         /* Flush all entries in the hash table */
 436                         ng_bridge_remove_hosts(priv, -1);
 437
 438                         /* Reset all loop detection counters and stats */
 439                         for (i = 0; i < NG_BRIDGE_MAX_LINKS; i++) {
 440                                 if (priv->links[i] == NULL)
 441                                         continue;
 442                                 priv->links[i]->loopCount = 0;
 443                                 bzero(&priv->links[i]->stats,
 444                                     sizeof(priv->links[i]->stats));
 445                         }
 446                         break;
 447                     }
 448                 case NGM_BRIDGE_GET_STATS:
 449                 case NGM_BRIDGE_CLR_STATS:
 450                 case NGM_BRIDGE_GETCLR_STATS:
 451                     {
 452                         struct ng_bridge_link *link;
 453                         int linkNum;
 454
 455                         /* Get link number */
 456                         if (msg->header.arglen != sizeof(u_int32_t)) {
 457                                 error = EINVAL;
 458                                 break;
 459                         }
 460                         linkNum = *((u_int32_t *)msg->data);
 461                         if (linkNum < 0 || linkNum >= NG_BRIDGE_MAX_LINKS) {
 462                                 error = EINVAL;
 463                                 break;
 464                         }
 465                         if ((link = priv->links[linkNum]) == NULL) {
 466                                 error = ENOTCONN;
 467                                 break;
 468                         }
 469
 470                         /* Get/clear stats */
 471                         if (msg->header.cmd != NGM_BRIDGE_CLR_STATS) {
 472                                 NG_MKRESPONSE(resp, msg,
 473                                     sizeof(link->stats), M_NOWAIT);
 474                                 if (resp == NULL) {
 475                                         error = ENOMEM;
 476                                         break;
 477                                 }
 478                                 bcopy(&link->stats,
 479                                     resp->data, sizeof(link->stats));
 480                         }
 481                         if (msg->header.cmd != NGM_BRIDGE_GET_STATS)
 482                                 bzero(&link->stats, sizeof(link->stats));
 483                         break;
 484                     }
 485                 case NGM_BRIDGE_GET_TABLE:
 486                     {
 487                         struct ng_bridge_host_ary *ary;
 488                         struct ng_bridge_hent *hent;
 489                         int i = 0, bucket;
 490
 491                         NG_MKRESPONSE(resp, msg, sizeof(*ary)
 492                             + (priv->numHosts * sizeof(*ary->hosts)), M_NOWAIT);
 493                         if (resp == NULL) {
 494                                 error = ENOMEM;
 495                                 break;
 496                         }
 497                         ary = (struct ng_bridge_host_ary *)resp->data;
 498                         ary->numHosts = priv->numHosts;
 499                         for (bucket = 0; bucket < priv->numBuckets; bucket++) {
 500                                 SLIST_FOREACH(hent, &priv->tab[bucket], next)
 501                                         ary->hosts[i++] = hent->host;
 502                         }
 503                         break;
 504                     }
 505                 case NGM_BRIDGE_SET_PERSISTENT:
 506                     {
 507                         priv->persistent = 1;
 508                         break;
 509                     }
 510                 default:
 511                         error = EINVAL;
 512                         break;
 513                 }
 514                 break;
 515         default:
 516                 error = EINVAL;
 517                 break;
 518         }
 519
 520         /* Done */
 521         NG_RESPOND_MSG(error, node, item, resp);
 522         NG_FREE_MSG(msg);
 523         return (error);
 524 }
 525
 526 /*
 527  * Receive data on a hook
 528  */
 529 static int
 530 ng_bridge_rcvdata(hook_p hook, item_p item)
 531 {
 532         const node_p node = NG_HOOK_NODE(hook);
 533         const priv_p priv = NG_NODE_PRIVATE(node);
 534         struct ng_bridge_host *host;
 535         struct ng_bridge_link *link;
 536         struct ether_header *eh;
 537         int error = 0, linkNum, linksSeen;
 538         int manycast;
 539         struct mbuf *m;
 540         struct ng_bridge_link *firstLink;
 541
 542         NGI_GET_M(item, m);
 543         /* Get link number */
 544         linkNum = (intptr_t)NG_HOOK_PRIVATE(hook);
 545         KASSERT(linkNum >= 0 && linkNum < NG_BRIDGE_MAX_LINKS,
 546             ("%s: linkNum=%u", __func__, linkNum));
 547         link = priv->links[linkNum];
 548         KASSERT(link != NULL, ("%s: link%d null", __func__, linkNum));
 549
 550         /* Sanity check packet and pull up header */
 551         if (m->m_pkthdr.len < ETHER_HDR_LEN) {
 552                 link->stats.recvRunts++;
 553                 NG_FREE_ITEM(item);
 554                 NG_FREE_M(m);
 555                 return (EINVAL);
 556         }
 557         if (m->m_len < ETHER_HDR_LEN && !(m = m_pullup(m, ETHER_HDR_LEN))) {
 558                 link->stats.memoryFailures++;
 559                 NG_FREE_ITEM(item);
 560                 return (ENOBUFS);
 561         }
 562         eh = mtod(m, struct ether_header *);
 563         if ((eh->ether_shost[0] & 1) != 0) {
 564                 link->stats.recvInvalid++;
 565                 NG_FREE_ITEM(item);
 566                 NG_FREE_M(m);
 567                 return (EINVAL);
 568         }
 569
 570         /* Is link disabled due to a loopback condition? */
 571         if (link->loopCount != 0) {
 572                 link->stats.loopDrops++;
 573                 NG_FREE_ITEM(item);
 574                 NG_FREE_M(m);
 575                 return (ELOOP);         /* XXX is this an appropriate error? */
 576         }
 577
 578         /* Update stats */
 579         link->stats.recvPackets++;
 580         link->stats.recvOctets += m->m_pkthdr.len;
 581         if ((manycast = (eh->ether_dhost[0] & 1)) != 0) {
 582                 if (ETHER_EQUAL(eh->ether_dhost, ng_bridge_bcast_addr)) {
 583                         link->stats.recvBroadcasts++;
 584                         manycast = 2;
 585                 } else
 586                         link->stats.recvMulticasts++;
 587         }
 588
 589         /* Look up packet's source Ethernet address in hashtable */
 590         if ((host = ng_bridge_get(priv, eh->ether_shost)) != NULL) {
 591
 592                 /* Update time since last heard from this host */
 593                 host->staleness = 0;
 594
 595                 /* Did host jump to a different link? */
 596                 if (host->linkNum != linkNum) {
 597
 598                         /*
 599                          * If the host's old link was recently established
 600                          * on the old link and it's already jumped to a new
 601                          * link, declare a loopback condition.
 602                          */
 603                         if (host->age < priv->conf.minStableAge) {
 604
 605                                 /* Log the problem */
 606                                 if (priv->conf.debugLevel >= 2) {
 607                                         struct ifnet *ifp = m->m_pkthdr.rcvif;
 608                                         char suffix[32];
 609
 610                                         if (ifp != NULL)
 611                                                 snprintf(suffix, sizeof(suffix),
 612                                                     " (%s)", ifp->if_xname);
 613                                         else
 614                                                 *suffix = '\0';
 615                                         log(LOG_WARNING, "ng_bridge: %s:"
 616                                             " loopback detected on %s%s\n",
 617                                             ng_bridge_nodename(node),
 618                                             NG_HOOK_NAME(hook), suffix);
 619                                 }
 620
 621                                 /* Mark link as linka non grata */
 622                                 link->loopCount = priv->conf.loopTimeout;
 623                                 link->stats.loopDetects++;
 624
 625                                 /* Forget all hosts on this link */
 626                                 ng_bridge_remove_hosts(priv, linkNum);
 627
 628                                 /* Drop packet */
 629                                 link->stats.loopDrops++;
 630                                 NG_FREE_ITEM(item);
 631                                 NG_FREE_M(m);
 632                                 return (ELOOP);         /* XXX appropriate? */
 633                         }
 634
 635                         /* Move host over to new link */
 636                         host->linkNum = linkNum;
 637                         host->age = 0;
 638                 }
 639         } else {
 640                 if (!ng_bridge_put(priv, eh->ether_shost, linkNum)) {
 641                         link->stats.memoryFailures++;
 642                         NG_FREE_ITEM(item);
 643                         NG_FREE_M(m);
 644                         return (ENOMEM);
 645                 }
 646         }
 647
 648         /* Run packet through ipfw processing, if enabled */
 649 #if 0
 650         if (priv->conf.ipfw[linkNum] && V_fw_enable && V_ip_fw_chk_ptr != NULL) {
 651                 /* XXX not implemented yet */
 652         }
 653 #endif
 654
 655         /*
 656          * If unicast and destination host known, deliver to host's link,
 657          * unless it is the same link as the packet came in on.
 658          */
 659         if (!manycast) {
 660
 661                 /* Determine packet destination link */
 662                 if ((host = ng_bridge_get(priv, eh->ether_dhost)) != NULL) {
 663                         struct ng_bridge_link *const destLink
 664                             = priv->links[host->linkNum];
 665
 666                         /* If destination same as incoming link, do nothing */
 667                         KASSERT(destLink != NULL,
 668                             ("%s: link%d null", __func__, host->linkNum));
 669                         if (destLink == link) {
 670                                 NG_FREE_ITEM(item);
 671                                 NG_FREE_M(m);
 672                                 return (0);
 673                         }
 674
 675                         /* Deliver packet out the destination link */
 676                         destLink->stats.xmitPackets++;
 677                         destLink->stats.xmitOctets += m->m_pkthdr.len;
 678                         NG_FWD_NEW_DATA(error, item, destLink->hook, m);
 679                         return (error);
 680                 }
 681
 682                 /* Destination host is not known */
 683                 link->stats.recvUnknown++;
 684         }
 685
 686         /* Distribute unknown, multicast, broadcast pkts to all other links */
 687         firstLink = NULL;
 688         for (linkNum = linksSeen = 0; linksSeen <= priv->numLinks; linkNum++) {
 689                 struct ng_bridge_link *destLink;
 690                 struct mbuf *m2 = NULL;
 691
 692                 /*
 693                  * If we have checked all the links then now
 694                  * send the original on its reserved link
 695                  */
 696                 if (linksSeen == priv->numLinks) {
 697                         /* If we never saw a good link, leave. */
 698                         if (firstLink == NULL) {
 699                                 NG_FREE_ITEM(item);
 700                                 NG_FREE_M(m);
 701                                 return (0);
 702                         }
 703                         destLink = firstLink;
 704                 } else {
 705                         destLink = priv->links[linkNum];
 706                         if (destLink != NULL)
 707                                 linksSeen++;
 708                         /* Skip incoming link and disconnected links */
 709                         if (destLink == NULL || destLink == link) {
 710                                 continue;
 711                         }
 712                         if (firstLink == NULL) {
 713                                 /*
 714                                  * This is the first usable link we have found.
 715                                  * Reserve it for the originals.
 716                                  * If we never find another we save a copy.
 717                                  */
 718                                 firstLink = destLink;
 719                                 continue;
 720                         }
 721
 722                         /*
 723                          * It's usable link but not the reserved (first) one.
 724                          * Copy mbuf info for sending.
 725                          */
 726                         m2 = m_dup(m, M_DONTWAIT);      /* XXX m_copypacket() */
 727                         if (m2 == NULL) {
 728                                 link->stats.memoryFailures++;
 729                                 NG_FREE_ITEM(item);
 730                                 NG_FREE_M(m);
 731                                 return (ENOBUFS);
 732                         }
 733                 }
 734
 735                 /* Update stats */
 736                 destLink->stats.xmitPackets++;
 737                 destLink->stats.xmitOctets += m->m_pkthdr.len;
 738                 switch (manycast) {
 739                 case 0:                                 /* unicast */
 740                         break;
 741                 case 1:                                 /* multicast */
 742                         destLink->stats.xmitMulticasts++;
 743                         break;
 744                 case 2:                                 /* broadcast */
 745                         destLink->stats.xmitBroadcasts++;
 746                         break;
 747                 }
 748
 749                 /* Send packet */
 750                 if (destLink == firstLink) {
 751                         /*
 752                          * If we've sent all the others, send the original
 753                          * on the first link we found.
 754                          */
 755                         NG_FWD_NEW_DATA(error, item, destLink->hook, m);
 756                         break; /* always done last - not really needed. */
 757                 } else {
 758                         NG_SEND_DATA_ONLY(error, destLink->hook, m2);
 759                 }
 760         }
 761         return (error);
 762 }
 763
 764 /*
 765  * Shutdown node
 766  */
 767 static int
 768 ng_bridge_shutdown(node_p node)
 769 {
 770         const priv_p priv = NG_NODE_PRIVATE(node);
 771
 772         /*
 773          * Shut down everything including the timer.  Even if the
 774          * callout has already been dequeued and is about to be
 775          * run, ng_bridge_timeout() won't be fired as the node
 776          * is already marked NGF_INVALID, so we're safe to free
 777          * the node now.
 778          */
 779         KASSERT(priv->numLinks == 0 && priv->numHosts == 0,
 780             ("%s: numLinks=%d numHosts=%d",
 781             __func__, priv->numLinks, priv->numHosts));
 782         ng_uncallout(&priv->timer, node);
 783         NG_NODE_SET_PRIVATE(node, NULL);
 784         NG_NODE_UNREF(node);
 785         free(priv->tab, M_NETGRAPH_BRIDGE);
 786         free(priv, M_NETGRAPH_BRIDGE);
 787         return (0);
 788 }
 789
 790 /*
 791  * Hook disconnection.
 792  */
 793 static int
 794 ng_bridge_disconnect(hook_p hook)
 795 {
 796         const priv_p priv = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
 797         int linkNum;
 798
 799         /* Get link number */
 800         linkNum = (intptr_t)NG_HOOK_PRIVATE(hook);
 801         KASSERT(linkNum >= 0 && linkNum < NG_BRIDGE_MAX_LINKS,
 802             ("%s: linkNum=%u", __func__, linkNum));
 803
 804         /* Remove all hosts associated with this link */
 805         ng_bridge_remove_hosts(priv, linkNum);
 806
 807         /* Free associated link information */
 808         KASSERT(priv->links[linkNum] != NULL, ("%s: no link", __func__));
 809         free(priv->links[linkNum], M_NETGRAPH_BRIDGE);
 810         priv->links[linkNum] = NULL;
 811         priv->numLinks--;
 812
 813         /* If no more hooks, go away */
 814         if ((NG_NODE_NUMHOOKS(NG_HOOK_NODE(hook)) == 0)
 815             && (NG_NODE_IS_VALID(NG_HOOK_NODE(hook)))
 816             && !priv->persistent) {
 817                 ng_rmnode_self(NG_HOOK_NODE(hook));
 818         }
 819         return (0);
 820 }
 821
 822 /******************************************************************
 823                     HASH TABLE FUNCTIONS
 824 ******************************************************************/
 825
 826 /*
 827  * Hash algorithm
 828  */
 829 #define HASH(addr,mask)         ( (((const u_int16_t *)(addr))[0]       \
 830                                  ^ ((const u_int16_t *)(addr))[1]       \
 831                                  ^ ((const u_int16_t *)(addr))[2]) & (mask) )
 832
 833 /*
 834  * Find a host entry in the table.
 835  */
 836 static struct ng_bridge_host *
 837 ng_bridge_get(priv_p priv, const u_char *addr)
 838 {
 839         const int bucket = HASH(addr, priv->hashMask);
 840         struct ng_bridge_hent *hent;
 841
 842         SLIST_FOREACH(hent, &priv->tab[bucket], next) {
 843                 if (ETHER_EQUAL(hent->host.addr, addr))
 844                         return (&hent->host);
 845         }
 846         return (NULL);
 847 }
 848
 849 /*
 850  * Add a new host entry to the table. This assumes the host doesn't
 851  * already exist in the table. Returns 1 on success, 0 if there
 852  * was a memory allocation failure.
 853  */
 854 static int
 855 ng_bridge_put(priv_p priv, const u_char *addr, int linkNum)
 856 {
 857         const int bucket = HASH(addr, priv->hashMask);
 858         struct ng_bridge_hent *hent;
 859
 860 #ifdef INVARIANTS
 861         /* Assert that entry does not already exist in hashtable */
 862         SLIST_FOREACH(hent, &priv->tab[bucket], next) {
 863                 KASSERT(!ETHER_EQUAL(hent->host.addr, addr),
 864                     ("%s: entry %6D exists in table", __func__, addr, ":"));
 865         }
 866 #endif
 867
 868         /* Allocate and initialize new hashtable entry */
 869         hent = malloc(sizeof(*hent), M_NETGRAPH_BRIDGE, M_NOWAIT);
 870         if (hent == NULL)
 871                 return (0);
 872         bcopy(addr, hent->host.addr, ETHER_ADDR_LEN);
 873         hent->host.linkNum = linkNum;
 874         hent->host.staleness = 0;
 875         hent->host.age = 0;
 876
 877         /* Add new element to hash bucket */
 878         SLIST_INSERT_HEAD(&priv->tab[bucket], hent, next);
 879         priv->numHosts++;
 880
 881         /* Resize table if necessary */
 882         ng_bridge_rehash(priv);
 883         return (1);
 884 }
 885
 886 /*
 887  * Resize the hash table. We try to maintain the number of buckets
 888  * such that the load factor is in the range 0.25 to 1.0.
 889  *
 890  * If we can't get the new memory then we silently fail. This is OK
 891  * because things will still work and we'll try again soon anyway.
 892  */
 893 static void
 894 ng_bridge_rehash(priv_p priv)
 895 {
 896         struct ng_bridge_bucket *newTab;
 897         int oldBucket, newBucket;
 898         int newNumBuckets;
 899         u_int newMask;
 900
 901         /* Is table too full or too empty? */
 902         if (priv->numHosts > priv->numBuckets
 903             && (priv->numBuckets << 1) <= MAX_BUCKETS)
 904                 newNumBuckets = priv->numBuckets << 1;
 905         else if (priv->numHosts < (priv->numBuckets >> 2)
 906             && (priv->numBuckets >> 2) >= MIN_BUCKETS)
 907                 newNumBuckets = priv->numBuckets >> 2;
 908         else
 909                 return;
 910         newMask = newNumBuckets - 1;
 911
 912         /* Allocate and initialize new table */
 913         newTab = malloc(newNumBuckets * sizeof(*newTab),
 914             M_NETGRAPH_BRIDGE, M_NOWAIT | M_ZERO);
 915         if (newTab == NULL)
 916                 return;
 917
 918         /* Move all entries from old table to new table */
 919         for (oldBucket = 0; oldBucket < priv->numBuckets; oldBucket++) {
 920                 struct ng_bridge_bucket *const oldList = &priv->tab[oldBucket];
 921
 922                 while (!SLIST_EMPTY(oldList)) {
 923                         struct ng_bridge_hent *const hent
 924                             = SLIST_FIRST(oldList);
 925
 926                         SLIST_REMOVE_HEAD(oldList, next);
 927                         newBucket = HASH(hent->host.addr, newMask);
 928                         SLIST_INSERT_HEAD(&newTab[newBucket], hent, next);
 929                 }
 930         }
 931
 932         /* Replace old table with new one */
 933         if (priv->conf.debugLevel >= 3) {
 934                 log(LOG_INFO, "ng_bridge: %s: table size %d -> %d\n",
 935                     ng_bridge_nodename(priv->node),
 936                     priv->numBuckets, newNumBuckets);
 937         }
 938         free(priv->tab, M_NETGRAPH_BRIDGE);
 939         priv->numBuckets = newNumBuckets;
 940         priv->hashMask = newMask;
 941         priv->tab = newTab;
 942         return;
 943 }
 944
 945 /******************************************************************
 946                     MISC FUNCTIONS
 947 ******************************************************************/
 948
 949 /*
 950  * Remove all hosts associated with a specific link from the hashtable.
 951  * If linkNum == -1, then remove all hosts in the table.
 952  */
 953 static void
 954 ng_bridge_remove_hosts(priv_p priv, int linkNum)
 955 {
 956         int bucket;
 957
 958         for (bucket = 0; bucket < priv->numBuckets; bucket++) {
 959                 struct ng_bridge_hent **hptr = &SLIST_FIRST(&priv->tab[bucket]);
 960
 961                 while (*hptr != NULL) {
 962                         struct ng_bridge_hent *const hent = *hptr;
 963
 964                         if (linkNum == -1 || hent->host.linkNum == linkNum) {
 965                                 *hptr = SLIST_NEXT(hent, next);
 966                                 free(hent, M_NETGRAPH_BRIDGE);
 967                                 priv->numHosts--;
 968                         } else
 969                                 hptr = &SLIST_NEXT(hent, next);
 970                 }
 971         }
 972 }
 973
 974 /*
 975  * Handle our once-per-second timeout event. We do two things:
 976  * we decrement link->loopCount for those links being muted due to
 977  * a detected loopback condition, and we remove any hosts from
 978  * the hashtable whom we haven't heard from in a long while.
 979  */
 980 static void
 981 ng_bridge_timeout(node_p node, hook_p hook, void *arg1, int arg2)
 982 {
 983         const priv_p priv = NG_NODE_PRIVATE(node);
 984         int bucket;
 985         int counter = 0;
 986         int linkNum;
 987
 988         /* Update host time counters and remove stale entries */
 989         for (bucket = 0; bucket < priv->numBuckets; bucket++) {
 990                 struct ng_bridge_hent **hptr = &SLIST_FIRST(&priv->tab[bucket]);
 991
 992                 while (*hptr != NULL) {
 993                         struct ng_bridge_hent *const hent = *hptr;
 994
 995                         /* Make sure host's link really exists */
 996                         KASSERT(priv->links[hent->host.linkNum] != NULL,
 997                             ("%s: host %6D on nonexistent link %d\n",
 998                             __func__, hent->host.addr, ":",
 999                             hent->host.linkNum));
1000
1001                         /* Remove hosts we haven't heard from in a while */
1002                         if (++hent->host.staleness >= priv->conf.maxStaleness) {
1003                                 *hptr = SLIST_NEXT(hent, next);
1004                                 free(hent, M_NETGRAPH_BRIDGE);
1005                                 priv->numHosts--;
1006                         } else {
1007                                 if (hent->host.age < 0xffff)
1008                                         hent->host.age++;
1009                                 hptr = &SLIST_NEXT(hent, next);
1010                                 counter++;
1011                         }
1012                 }
1013         }
1014         KASSERT(priv->numHosts == counter,
1015             ("%s: hosts: %d != %d", __func__, priv->numHosts, counter));
1016
1017         /* Decrease table size if necessary */
1018         ng_bridge_rehash(priv);
1019
1020         /* Decrease loop counter on muted looped back links */
1021         for (counter = linkNum = 0; linkNum < NG_BRIDGE_MAX_LINKS; linkNum++) {
1022                 struct ng_bridge_link *const link = priv->links[linkNum];
1023
1024                 if (link != NULL) {
1025                         if (link->loopCount != 0) {
1026                                 link->loopCount--;
1027                                 if (link->loopCount == 0
1028                                     && priv->conf.debugLevel >= 2) {
1029                                         log(LOG_INFO, "ng_bridge: %s:"
1030                                             " restoring looped back link%d\n",
1031                                             ng_bridge_nodename(node), linkNum);
1032                                 }
1033                         }
1034                         counter++;
1035                 }
1036         }
1037         KASSERT(priv->numLinks == counter,
1038             ("%s: links: %d != %d", __func__, priv->numLinks, counter));
1039
1040         /* Register a new timeout, keeping the existing node reference */
1041         ng_callout(&priv->timer, node, NULL, hz, ng_bridge_timeout, NULL, 0);
1042 }
1043
1044 /*
1045  * Return node's "name", even if it doesn't have one.
1046  */
1047 static const char *
1048 ng_bridge_nodename(node_p node)
1049 {
1050         static char name[NG_NODESIZ];
1051
1052         if (NG_NODE_NAME(node) != NULL)
1053                 snprintf(name, sizeof(name), "%s", NG_NODE_NAME(node));
1054         else
1055                 snprintf(name, sizeof(name), "[%x]", ng_node2ID(node));
1056         return name;
1057 }
1058