usr.sbin/mrouted/rsrr.c

   1 /*
   2  * Copyright (c) 1993 by the University of Southern California
   3  * All rights reserved.
   4  *
   5  * Permission to use, copy, modify, and distribute this software and its
   6  * documentation in source and binary forms for non-commercial purposes
   7  * and without fee is hereby granted, provided that the above copyright
   8  * notice appear in all copies and that both the copyright notice and
   9  * this permission notice appear in supporting documentation. and that
  10  * any documentation, advertising materials, and other materials related
  11  * to such distribution and use acknowledge that the software was
  12  * developed by the University of Southern California, Information
  13  * Sciences Institute.  The name of the University may not be used to
  14  * endorse or promote products derived from this software without
  15  * specific prior written permission.
  16  *
  17  * THE UNIVERSITY OF SOUTHERN CALIFORNIA makes no representations about
  18  * the suitability of this software for any purpose.  THIS SOFTWARE IS
  19  * PROVIDED "AS IS" AND WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES,
  20  * INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
  21  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
  22  *
  23  * Other copyrights might apply to parts of this software and are so
  24  * noted when applicable.
  25  *
  26  * $FreeBSD: src/usr.sbin/mrouted/rsrr.c,v 1.8.2.1 2001/05/12 09:48:20 kris Exp $
  27  * $DragonFly: src/usr.sbin/mrouted/rsrr.c,v 1.4 2004/03/15 18:10:28 dillon Exp $
  28  */
  29
  30 /* RSRR code written by Daniel Zappala, USC Information Sciences Institute,
  31  * April 1995.
  32  */
  33
  34 /* May 1995 -- Added support for Route Change Notification */
  35
  36 #ifdef RSRR
  37
  38 #include "defs.h"
  39 #include <sys/param.h>
  40 #ifdef HAVE_SA_LEN
  41 #include <stddef.h>     /* for offsetof */
  42 #endif
  43
  44 /*
  45  * Exported variables.
  46  */
  47 int rsrr_socket;                        /* interface to reservation protocol */
  48
  49 /*
  50  * Global RSRR variables.
  51  */
  52 char rsrr_recv_buf[RSRR_MAX_LEN];       /* RSRR receive buffer */
  53 char rsrr_send_buf[RSRR_MAX_LEN];       /* RSRR send buffer */
  54
  55 struct sockaddr_un client_addr;
  56 int client_length = sizeof(client_addr);
  57
  58
  59 /*
  60  * Procedure definitions needed internally.
  61  */
  62 static void     rsrr_accept(int recvlen);
  63 static void     rsrr_accept_iq(void);
  64 static int      rsrr_accept_rq(struct rsrr_rq *route_query, int flags,
  65                                         struct gtable *gt_notify);
  66 static void     rsrr_read(int, fd_set *);
  67 static int      rsrr_send(int sendlen);
  68 static void     rsrr_cache(struct gtable *gt,
  69                                         struct rsrr_rq *route_query);
  70
  71 /* Initialize RSRR socket */
  72 void
  73 rsrr_init(void)
  74 {
  75     int servlen;
  76     struct sockaddr_un serv_addr;
  77
  78     if ((rsrr_socket = socket(AF_UNIX, SOCK_DGRAM, 0)) < 0)
  79         log(LOG_ERR, errno, "Can't create RSRR socket");
  80
  81     unlink(RSRR_SERV_PATH);
  82     bzero((char *) &serv_addr, sizeof(serv_addr));
  83     serv_addr.sun_family = AF_UNIX;
  84     strcpy(serv_addr.sun_path, RSRR_SERV_PATH);
  85 #ifdef HAVE_SA_LEN
  86     servlen = offsetof(struct sockaddr_un, sun_path) +
  87                 strlen(serv_addr.sun_path);
  88     serv_addr.sun_len = servlen;
  89 #else
  90     servlen = sizeof(serv_addr.sun_family) + strlen(serv_addr.sun_path);
  91 #endif
  92
  93     if (bind(rsrr_socket, (struct sockaddr *) &serv_addr, servlen) < 0)
  94         log(LOG_ERR, errno, "Can't bind RSRR socket");
  95
  96     if (register_input_handler(rsrr_socket, rsrr_read) < 0)
  97         log(LOG_WARNING, 0, "Couldn't register RSRR as an input handler");
  98 }
  99
 100 /* Read a message from the RSRR socket */
 101 static void
 102 rsrr_read(int f, fd_set *rfd)
 103 {
 104     int rsrr_recvlen;
 105
 106     bzero((char *) &client_addr, sizeof(client_addr));
 107     rsrr_recvlen = recvfrom(rsrr_socket, rsrr_recv_buf, sizeof(rsrr_recv_buf),
 108                             0, (struct sockaddr *)&client_addr, &client_length);
 109     if (rsrr_recvlen < 0) {
 110         if (errno != EINTR)
 111             log(LOG_ERR, errno, "RSRR recvfrom");
 112         return;
 113     }
 114     rsrr_accept(rsrr_recvlen);
 115 }
 116
 117 /* Accept a message from the reservation protocol and take
 118  * appropriate action.
 119  */
 120 static void
 121 rsrr_accept(int recvlen)
 122 {
 123     struct rsrr_header *rsrr;
 124     struct rsrr_rq *route_query;
 125
 126     if (recvlen < RSRR_HEADER_LEN) {
 127         log(LOG_WARNING, 0,
 128             "Received RSRR packet of %d bytes, which is less than min size",
 129             recvlen);
 130         return;
 131     }
 132
 133     rsrr = (struct rsrr_header *) rsrr_recv_buf;
 134
 135     if (rsrr->version > RSRR_MAX_VERSION) {
 136         log(LOG_WARNING, 0,
 137             "Received RSRR packet version %d, which I don't understand",
 138             rsrr->version);
 139         return;
 140     }
 141
 142     switch (rsrr->version) {
 143       case 1:
 144         switch (rsrr->type) {
 145           case RSRR_INITIAL_QUERY:
 146             /* Send Initial Reply to client */
 147             IF_DEBUG(DEBUG_RSRR)
 148             log(LOG_DEBUG, 0, "Received Initial Query\n");
 149             rsrr_accept_iq();
 150             break;
 151           case RSRR_ROUTE_QUERY:
 152             /* Check size */
 153             if (recvlen < RSRR_RQ_LEN) {
 154                 log(LOG_WARNING, 0,
 155                     "Received Route Query of %d bytes, which is too small",
 156                     recvlen);
 157                 break;
 158             }
 159             /* Get the query */
 160             route_query = (struct rsrr_rq *) (rsrr_recv_buf + RSRR_HEADER_LEN);
 161             IF_DEBUG(DEBUG_RSRR)
 162             log(LOG_DEBUG, 0,
 163                 "Received Route Query for src %s grp %s notification %d",
 164                 inet_fmt(route_query->source_addr.s_addr, s1),
 165                 inet_fmt(route_query->dest_addr.s_addr,s2),
 166                 BIT_TST(rsrr->flags,RSRR_NOTIFICATION_BIT));
 167             /* Send Route Reply to client */
 168             rsrr_accept_rq(route_query,rsrr->flags,NULL);
 169             break;
 170           default:
 171             log(LOG_WARNING, 0,
 172                 "Received RSRR packet type %d, which I don't handle",
 173                 rsrr->type);
 174             break;
 175         }
 176         break;
 177
 178       default:
 179         log(LOG_WARNING, 0,
 180             "Received RSRR packet version %d, which I don't understand",
 181             rsrr->version);
 182         break;
 183     }
 184 }
 185
 186 /* Send an Initial Reply to the reservation protocol. */
 187 static void
 188 rsrr_accept_iq(void)
 189 {
 190     struct rsrr_header *rsrr;
 191     struct rsrr_vif *vif_list;
 192     struct uvif *v;
 193     int vifi, sendlen;
 194
 195     /* Check for space.  There should be room for plenty of vifs,
 196      * but we should check anyway.
 197      */
 198     if (numvifs > RSRR_MAX_VIFS) {
 199         log(LOG_WARNING, 0,
 200             "Can't send RSRR Route Reply because %d is too many vifs",
 201             numvifs);
 202         return;
 203     }
 204
 205     /* Set up message */
 206     rsrr = (struct rsrr_header *) rsrr_send_buf;
 207     rsrr->version = 1;
 208     rsrr->type = RSRR_INITIAL_REPLY;
 209     rsrr->flags = 0;
 210     rsrr->num = numvifs;
 211
 212     vif_list = (struct rsrr_vif *) (rsrr_send_buf + RSRR_HEADER_LEN);
 213
 214     /* Include the vif list. */
 215     for (vifi=0, v = uvifs; vifi < numvifs; vifi++, v++) {
 216         vif_list[vifi].id = vifi;
 217         vif_list[vifi].status = 0;
 218         if (v->uv_flags & VIFF_DISABLED)
 219             BIT_SET(vif_list[vifi].status,RSRR_DISABLED_BIT);
 220         vif_list[vifi].threshold = v->uv_threshold;
 221         vif_list[vifi].local_addr.s_addr = v->uv_lcl_addr;
 222     }
 223
 224     /* Get the size. */
 225     sendlen = RSRR_HEADER_LEN + numvifs*RSRR_VIF_LEN;
 226
 227     /* Send it. */
 228     IF_DEBUG(DEBUG_RSRR)
 229     log(LOG_DEBUG, 0, "Send RSRR Initial Reply");
 230     rsrr_send(sendlen);
 231 }
 232
 233 /* Send a Route Reply to the reservation protocol.  The Route Query
 234  * contains the query to which we are responding.  The flags contain
 235  * the incoming flags from the query or, for route change
 236  * notification, the flags that should be set for the reply.  The
 237  * kernel table entry contains the routing info to use for a route
 238  * change notification.
 239  */
 240 static int
 241 rsrr_accept_rq(struct rsrr_rq *route_query, int flags, struct gtable *gt_notify)
 242 {
 243     struct rsrr_header *rsrr;
 244     struct rsrr_rr *route_reply;
 245     struct gtable *gt,local_g;
 246     struct rtentry *r;
 247     int sendlen;
 248     u_long mcastgrp;
 249
 250     /* Set up message */
 251     rsrr = (struct rsrr_header *) rsrr_send_buf;
 252     rsrr->version = 1;
 253     rsrr->type = RSRR_ROUTE_REPLY;
 254     rsrr->flags = 0;
 255     rsrr->num = 0;
 256
 257     route_reply = (struct rsrr_rr *) (rsrr_send_buf + RSRR_HEADER_LEN);
 258     route_reply->dest_addr.s_addr = route_query->dest_addr.s_addr;
 259     route_reply->source_addr.s_addr = route_query->source_addr.s_addr;
 260     route_reply->query_id = route_query->query_id;
 261
 262     /* Blank routing entry for error. */
 263     route_reply->in_vif = 0;
 264     route_reply->reserved = 0;
 265     route_reply->out_vif_bm = 0;
 266
 267     /* Get the size. */
 268     sendlen = RSRR_RR_LEN;
 269
 270     /* If kernel table entry is defined, then we are sending a Route Reply
 271      * due to a Route Change Notification event.  Use the kernel table entry
 272      * to supply the routing info.
 273      */
 274     if (gt_notify) {
 275         /* Set flags */
 276         rsrr->flags = flags;
 277         /* Include the routing entry. */
 278         route_reply->in_vif = gt_notify->gt_route->rt_parent;
 279         if (BIT_TST(flags,RSRR_NOTIFICATION_BIT))
 280             route_reply->out_vif_bm = gt_notify->gt_grpmems;
 281         else
 282             route_reply->out_vif_bm = 0;
 283     } else if (find_src_grp(route_query->source_addr.s_addr, 0,
 284                             route_query->dest_addr.s_addr)) {
 285
 286         /* Found kernel entry. Code taken from add_table_entry() */
 287         gt = gtp ? gtp->gt_gnext : kernel_table;
 288
 289         /* Include the routing entry. */
 290         route_reply->in_vif = gt->gt_route->rt_parent;
 291         route_reply->out_vif_bm = gt->gt_grpmems;
 292
 293         /* Cache reply if using route change notification. */
 294         if BIT_TST(flags,RSRR_NOTIFICATION_BIT) {
 295             rsrr_cache(gt,route_query);
 296             BIT_SET(rsrr->flags,RSRR_NOTIFICATION_BIT);
 297         }
 298
 299     } else {
 300         /* No kernel entry; use routing table. */
 301         r = determine_route(route_query->source_addr.s_addr);
 302
 303         if (r != NULL) {
 304             /* We need to mimic what will happen if a data packet
 305              * is forwarded by multicast routing -- the kernel will
 306              * make an upcall and mrouted will install a route in the kernel.
 307              * Our outgoing vif bitmap should reflect what that table
 308              * will look like.  Grab code from add_table_entry().
 309              * This is gross, but it's probably better to be accurate.
 310              */
 311
 312             gt = &local_g;
 313             mcastgrp = route_query->dest_addr.s_addr;
 314
 315             gt->gt_mcastgrp     = mcastgrp;
 316             gt->gt_grpmems      = 0;
 317             gt->gt_scope        = 0;
 318             gt->gt_route        = r;
 319
 320             /* obtain the multicast group membership list */
 321             determine_forwvifs(gt);
 322
 323             /* Include the routing entry. */
 324             route_reply->in_vif = gt->gt_route->rt_parent;
 325             route_reply->out_vif_bm = gt->gt_grpmems;
 326
 327         } else {
 328             /* Set error bit. */
 329             BIT_SET(rsrr->flags,RSRR_ERROR_BIT);
 330         }
 331     }
 332
 333     IF_DEBUG(DEBUG_RSRR)
 334     log(LOG_DEBUG, 0, "%sSend RSRR Route Reply for src %s dst %s in vif %d out vif %d\n",
 335         gt_notify ? "Route Change: " : "",
 336         inet_fmt(route_reply->source_addr.s_addr,s1),
 337         inet_fmt(route_reply->dest_addr.s_addr,s2),
 338         route_reply->in_vif,route_reply->out_vif_bm);
 339
 340     /* Send it. */
 341     return rsrr_send(sendlen);
 342 }
 343
 344 /* Send an RSRR message. */
 345 static int
 346 rsrr_send(int sendlen)
 347 {
 348     int error;
 349
 350     /* Send it. */
 351     error = sendto(rsrr_socket, rsrr_send_buf, sendlen, 0,
 352                    (struct sockaddr *)&client_addr, client_length);
 353
 354     /* Check for errors. */
 355     if (error < 0) {
 356         log(LOG_WARNING, errno, "Failed send on RSRR socket");
 357     } else if (error != sendlen) {
 358         log(LOG_WARNING, 0,
 359             "Sent only %d out of %d bytes on RSRR socket\n", error, sendlen);
 360     }
 361     return error;
 362 }
 363
 364 /* Cache a message being sent to a client.  Currently only used for
 365  * caching Route Reply messages for route change notification.
 366  */
 367 static void
 368 rsrr_cache(struct gtable *gt, struct rsrr_rq *route_query)
 369 {
 370     struct rsrr_cache *rc, **rcnp;
 371     struct rsrr_header *rsrr;
 372
 373     rsrr = (struct rsrr_header *) rsrr_send_buf;
 374
 375     rcnp = &gt->gt_rsrr_cache;
 376     while ((rc = *rcnp) != NULL) {
 377         if ((rc->route_query.source_addr.s_addr ==
 378              route_query->source_addr.s_addr) &&
 379             (rc->route_query.dest_addr.s_addr ==
 380              route_query->dest_addr.s_addr) &&
 381             (!strcmp(rc->client_addr.sun_path,client_addr.sun_path))) {
 382             /* Cache entry already exists.
 383              * Check if route notification bit has been cleared.
 384              */
 385             if (!BIT_TST(rsrr->flags,RSRR_NOTIFICATION_BIT)) {
 386                 /* Delete cache entry. */
 387                 *rcnp = rc->next;
 388                 free(rc);
 389             } else {
 390                 /* Update */
 391                 rc->route_query.query_id = route_query->query_id;
 392                 IF_DEBUG(DEBUG_RSRR)
 393                 log(LOG_DEBUG, 0,
 394                         "Update cached query id %ld from client %s\n",
 395                         rc->route_query.query_id, rc->client_addr.sun_path);
 396             }
 397             return;
 398         }
 399         rcnp = &rc->next;
 400     }
 401
 402     /* Cache entry doesn't already exist.  Create one and insert at
 403      * front of list.
 404      */
 405     rc = (struct rsrr_cache *) malloc(sizeof(struct rsrr_cache));
 406     if (rc == NULL)
 407         log(LOG_ERR, 0, "ran out of memory");
 408     rc->route_query.source_addr.s_addr = route_query->source_addr.s_addr;
 409     rc->route_query.dest_addr.s_addr = route_query->dest_addr.s_addr;
 410     rc->route_query.query_id = route_query->query_id;
 411     strcpy(rc->client_addr.sun_path, client_addr.sun_path);
 412     rc->client_length = client_length;
 413     rc->next = gt->gt_rsrr_cache;
 414     gt->gt_rsrr_cache = rc;
 415     IF_DEBUG(DEBUG_RSRR)
 416     log(LOG_DEBUG, 0, "Cached query id %ld from client %s\n",
 417            rc->route_query.query_id,rc->client_addr.sun_path);
 418 }
 419
 420 /* Send all the messages in the cache.  Currently this is used to send
 421  * all the cached Route Reply messages for route change notification.
 422  */
 423 void
 424 rsrr_cache_send(struct gtable *gt, int notify)
 425 {
 426     struct rsrr_cache *rc, **rcnp;
 427     int flags = 0;
 428
 429     if (notify)
 430         BIT_SET(flags,RSRR_NOTIFICATION_BIT);
 431
 432     rcnp = &gt->gt_rsrr_cache;
 433     while ((rc = *rcnp) != NULL) {
 434         if (rsrr_accept_rq(&rc->route_query,flags,gt) < 0) {
 435             IF_DEBUG(DEBUG_RSRR)
 436             log(LOG_DEBUG, 0, "Deleting cached query id %ld from client %s\n",
 437                    rc->route_query.query_id,rc->client_addr.sun_path);
 438             /* Delete cache entry. */
 439             *rcnp = rc->next;
 440             free(rc);
 441         } else {
 442             rcnp = &rc->next;
 443         }
 444     }
 445 }
 446
 447 /* Clean the cache by deleting all entries. */
 448 void
 449 rsrr_cache_clean(struct gtable *gt)
 450 {
 451     struct rsrr_cache *rc, *rc_next;
 452
 453     IF_DEBUG(DEBUG_RSRR)
 454     log(LOG_DEBUG, 0, "cleaning cache for group %s\n",
 455                         inet_fmt(gt->gt_mcastgrp, s1));
 456     rc = gt->gt_rsrr_cache;
 457     while (rc) {
 458         rc_next = rc->next;
 459         free(rc);
 460         rc = rc_next;
 461     }
 462     gt->gt_rsrr_cache = NULL;
 463 }
 464
 465 void
 466 rsrr_clean(void)
 467 {
 468     unlink(RSRR_SERV_PATH);
 469 }
 470
 471 #endif /* RSRR */