sys/netinet/igmp.c

   1 /*
   2  * Copyright (c) 1988 Stephen Deering.
   3  * Copyright (c) 1992, 1993
   4  *      The Regents of the University of California.  All rights reserved.
   5  *
   6  * This code is derived from software contributed to Berkeley by
   7  * Stephen Deering of Stanford University.
   8  *
   9  * Redistribution and use in source and binary forms, with or without
  10  * modification, are permitted provided that the following conditions
  11  * are met:
  12  * 1. Redistributions of source code must retain the above copyright
  13  *    notice, this list of conditions and the following disclaimer.
  14  * 2. Redistributions in binary form must reproduce the above copyright
  15  *    notice, this list of conditions and the following disclaimer in the
  16  *    documentation and/or other materials provided with the distribution.
  17  * 3. Neither the name of the University nor the names of its contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  *
  33  *      @(#)igmp.c      8.1 (Berkeley) 7/19/93
  34  * $FreeBSD: src/sys/netinet/igmp.c,v 1.29.2.2 2003/01/23 21:06:44 sam Exp $
  35  */
  36
  37 /*
  38  * Internet Group Management Protocol (IGMP) routines.
  39  *
  40  * Written by Steve Deering, Stanford, May 1988.
  41  * Modified by Rosen Sharma, Stanford, Aug 1994.
  42  * Modified by Bill Fenner, Xerox PARC, Feb 1995.
  43  * Modified to fully comply to IGMPv2 by Bill Fenner, Oct 1995.
  44  *
  45  * MULTICAST Revision: 3.5.1.4
  46  */
  47
  48 #include <sys/param.h>
  49 #include <sys/systm.h>
  50 #include <sys/malloc.h>
  51 #include <sys/mbuf.h>
  52 #include <sys/socket.h>
  53 #include <sys/protosw.h>
  54 #include <sys/kernel.h>
  55 #include <sys/sysctl.h>
  56 #include <sys/in_cksum.h>
  57 #include <sys/thread2.h>
  58
  59 #include <machine/stdarg.h>
  60
  61 #include <net/if.h>
  62 #include <net/route.h>
  63 #include <net/netmsg2.h>
  64 #include <net/netisr2.h>
  65
  66 #include <netinet/in.h>
  67 #include <netinet/in_var.h>
  68 #include <netinet/in_systm.h>
  69 #include <netinet/ip.h>
  70 #include <netinet/ip_var.h>
  71 #include <netinet/igmp.h>
  72 #include <netinet/igmp_var.h>
  73
  74 static MALLOC_DEFINE(M_IGMP, "igmp", "igmp state");
  75
  76 static struct router_info *
  77                 find_rti (struct ifnet *ifp);
  78
  79 static struct igmpstat igmpstat;
  80
  81 SYSCTL_STRUCT(_net_inet_igmp, IGMPCTL_STATS, stats, CTLFLAG_RW,
  82         &igmpstat, igmpstat, "IGMP statistics");
  83
  84 static int igmp_timers_are_running;
  85 static u_long igmp_all_hosts_group;
  86 static u_long igmp_all_rtrs_group;
  87 static struct mbuf *router_alert;
  88 static struct router_info *Head;
  89
  90 static struct netmsg_base igmp_slowtimo_netmsg;
  91 static struct netmsg_base igmp_fasttimo_netmsg;
  92
  93 static void igmp_sendpkt (struct in_multi *, int, unsigned long);
  94 static void igmp_slowtimo_dispatch(netmsg_t);
  95 static void igmp_fasttimo_dispatch(netmsg_t);
  96
  97 void
  98 igmp_init(void)
  99 {
 100         struct ipoption *ra;
 101
 102         /*
 103          * To avoid byte-swapping the same value over and over again.
 104          */
 105         igmp_all_hosts_group = htonl(INADDR_ALLHOSTS_GROUP);
 106         igmp_all_rtrs_group = htonl(INADDR_ALLRTRS_GROUP);
 107
 108         igmp_timers_are_running = 0;
 109
 110         /*
 111          * Construct a Router Alert option to use in outgoing packets
 112          */
 113         MGET(router_alert, M_NOWAIT, MT_DATA);
 114         ra = mtod(router_alert, struct ipoption *);
 115         ra->ipopt_dst.s_addr = 0;
 116         ra->ipopt_list[0] = IPOPT_RA;   /* Router Alert Option */
 117         ra->ipopt_list[1] = 0x04;       /* 4 bytes long */
 118         ra->ipopt_list[2] = 0x00;
 119         ra->ipopt_list[3] = 0x00;
 120         router_alert->m_len = sizeof(ra->ipopt_dst) + ra->ipopt_list[1];
 121
 122         Head = NULL;
 123
 124         netmsg_init(&igmp_slowtimo_netmsg, NULL, &netisr_adone_rport,
 125             MSGF_PRIORITY, igmp_slowtimo_dispatch);
 126         netmsg_init(&igmp_fasttimo_netmsg, NULL, &netisr_adone_rport,
 127             MSGF_PRIORITY, igmp_fasttimo_dispatch);
 128 }
 129
 130 static struct router_info *
 131 find_rti(struct ifnet *ifp)
 132 {
 133         struct router_info *rti = Head;
 134
 135 #ifdef IGMP_DEBUG
 136         kprintf("[igmp.c, _find_rti] --> entering \n");
 137 #endif
 138         while (rti) {
 139                 if (rti->rti_ifp == ifp) {
 140 #ifdef IGMP_DEBUG
 141                         kprintf("[igmp.c, _find_rti] --> found old entry \n");
 142 #endif
 143                         return rti;
 144                 }
 145                 rti = rti->rti_next;
 146         }
 147         rti = kmalloc(sizeof *rti, M_IGMP, M_INTWAIT);
 148         rti->rti_ifp = ifp;
 149         rti->rti_type = IGMP_V2_ROUTER;
 150         rti->rti_time = 0;
 151         rti->rti_next = Head;
 152         Head = rti;
 153 #ifdef IGMP_DEBUG
 154         kprintf("[igmp.c, _find_rti] --> created an entry \n");
 155 #endif
 156         return rti;
 157 }
 158
 159 int
 160 igmp_input(struct mbuf **mp, int *offp, int proto)
 161 {
 162         struct mbuf *m = *mp;
 163         int iphlen;
 164         struct igmp *igmp;
 165         struct ip *ip;
 166         int igmplen;
 167         struct ifnet *ifp = m->m_pkthdr.rcvif;
 168         int minlen;
 169         struct in_multi *inm;
 170         struct in_ifaddr *ia;
 171         struct in_multistep step;
 172         struct router_info *rti;
 173         int timer; /** timer value in the igmp query header **/
 174
 175         iphlen = *offp;
 176         *mp = NULL;
 177
 178         ++igmpstat.igps_rcv_total;
 179
 180         ip = mtod(m, struct ip *);
 181         igmplen = ip->ip_len;
 182
 183         /*
 184          * Validate lengths
 185          */
 186         if (igmplen < IGMP_MINLEN) {
 187                 ++igmpstat.igps_rcv_tooshort;
 188                 m_freem(m);
 189                 return(IPPROTO_DONE);
 190         }
 191         minlen = iphlen + IGMP_MINLEN;
 192         if ((m->m_flags & M_EXT || m->m_len < minlen) &&
 193             (m = m_pullup(m, minlen)) == NULL) {
 194                 ++igmpstat.igps_rcv_tooshort;
 195                 return(IPPROTO_DONE);
 196         }
 197
 198         /*
 199          * Validate checksum
 200          */
 201         m->m_data += iphlen;
 202         m->m_len -= iphlen;
 203         igmp = mtod(m, struct igmp *);
 204         if (in_cksum(m, igmplen)) {
 205                 ++igmpstat.igps_rcv_badsum;
 206                 m_freem(m);
 207                 return(IPPROTO_DONE);
 208         }
 209         m->m_data -= iphlen;
 210         m->m_len += iphlen;
 211
 212         ip = mtod(m, struct ip *);
 213         timer = igmp->igmp_code * PR_FASTHZ / IGMP_TIMER_SCALE;
 214         if (timer == 0)
 215                 timer = 1;
 216         rti = find_rti(ifp);
 217
 218         /*
 219          * In the IGMPv2 specification, there are 3 states and a flag.
 220          *
 221          * In Non-Member state, we simply don't have a membership record.
 222          * In Delaying Member state, our timer is running (inm->inm_timer)
 223          * In Idle Member state, our timer is not running (inm->inm_timer==0)
 224          *
 225          * The flag is inm->inm_state, it is set to IGMP_OTHERMEMBER if
 226          * we have heard a report from another member, or IGMP_IREPORTEDLAST
 227          * if I sent the last report.
 228          */
 229         switch (igmp->igmp_type) {
 230
 231         case IGMP_MEMBERSHIP_QUERY:
 232                 ++igmpstat.igps_rcv_queries;
 233
 234                 if (ifp->if_flags & IFF_LOOPBACK)
 235                         break;
 236
 237                 if (igmp->igmp_code == 0) {
 238                         /*
 239                          * Old router.  Remember that the querier on this
 240                          * interface is old, and set the timer to the
 241                          * value in RFC 1112.
 242                          */
 243
 244                         rti->rti_type = IGMP_V1_ROUTER;
 245                         rti->rti_time = 0;
 246
 247                         timer = IGMP_MAX_HOST_REPORT_DELAY * PR_FASTHZ;
 248
 249                         if (ip->ip_dst.s_addr != igmp_all_hosts_group ||
 250                             igmp->igmp_group.s_addr != 0) {
 251                                 ++igmpstat.igps_rcv_badqueries;
 252                                 m_freem(m);
 253                                 return(IPPROTO_DONE);
 254                         }
 255                 } else {
 256                         /*
 257                          * New router.  Simply do the new validity check.
 258                          */
 259
 260                         if (igmp->igmp_group.s_addr != 0 &&
 261                             !IN_MULTICAST(ntohl(igmp->igmp_group.s_addr))) {
 262                                 ++igmpstat.igps_rcv_badqueries;
 263                                 m_freem(m);
 264                                 return(IPPROTO_DONE);
 265                         }
 266                 }
 267
 268                 /*
 269                  * - Start the timers in all of our membership records
 270                  *   that the query applies to for the interface on
 271                  *   which the query arrived excl. those that belong
 272                  *   to the "all-hosts" group (224.0.0.1).
 273                  * - Restart any timer that is already running but has
 274                  *   a value longer than the requested timeout.
 275                  * - Use the value specified in the query message as
 276                  *   the maximum timeout.
 277                  */
 278                 IN_FIRST_MULTI(step, inm);
 279                 while (inm != NULL) {
 280                         if (inm->inm_ifp == ifp &&
 281                             inm->inm_addr.s_addr != igmp_all_hosts_group &&
 282                             (igmp->igmp_group.s_addr == 0 ||
 283                              igmp->igmp_group.s_addr == inm->inm_addr.s_addr)) {
 284                                 if (inm->inm_timer == 0 ||
 285                                     inm->inm_timer > timer) {
 286                                         inm->inm_timer =
 287                                                 IGMP_RANDOM_DELAY(timer);
 288                                         igmp_timers_are_running = 1;
 289                                 }
 290                         }
 291                         IN_NEXT_MULTI(step, inm);
 292                 }
 293
 294                 break;
 295
 296         case IGMP_V1_MEMBERSHIP_REPORT:
 297         case IGMP_V2_MEMBERSHIP_REPORT:
 298                 /*
 299                  * For fast leave to work, we have to know that we are the
 300                  * last person to send a report for this group.  Reports
 301                  * can potentially get looped back if we are a multicast
 302                  * router, so discard reports sourced by me.
 303                  */
 304                 ia = IFP_TO_IA(ifp);
 305                 if (ia && ip->ip_src.s_addr == IA_SIN(ia)->sin_addr.s_addr)
 306                         break;
 307
 308                 ++igmpstat.igps_rcv_reports;
 309
 310                 if (ifp->if_flags & IFF_LOOPBACK)
 311                         break;
 312
 313                 if (!IN_MULTICAST(ntohl(igmp->igmp_group.s_addr))) {
 314                         ++igmpstat.igps_rcv_badreports;
 315                         m_freem(m);
 316                         return(IPPROTO_DONE);
 317                 }
 318
 319                 /*
 320                  * KLUDGE: if the IP source address of the report has an
 321                  * unspecified (i.e., zero) subnet number, as is allowed for
 322                  * a booting host, replace it with the correct subnet number
 323                  * so that a process-level multicast routing demon can
 324                  * determine which subnet it arrived from.  This is necessary
 325                  * to compensate for the lack of any way for a process to
 326                  * determine the arrival interface of an incoming packet.
 327                  */
 328                 if ((ntohl(ip->ip_src.s_addr) & IN_CLASSA_NET) == 0)
 329                         if (ia) ip->ip_src.s_addr = htonl(ia->ia_subnet);
 330
 331                 /*
 332                  * If we belong to the group being reported, stop
 333                  * our timer for that group.
 334                  */
 335                 inm = IN_LOOKUP_MULTI(&igmp->igmp_group, ifp);
 336
 337                 if (inm != NULL) {
 338                         inm->inm_timer = 0;
 339                         ++igmpstat.igps_rcv_ourreports;
 340
 341                         inm->inm_state = IGMP_OTHERMEMBER;
 342                 }
 343
 344                 break;
 345         }
 346
 347         /*
 348          * Pass all valid IGMP packets up to any process(es) listening
 349          * on a raw IGMP socket.
 350          */
 351         *mp = m;
 352         rip_input(mp, offp, proto);
 353         return(IPPROTO_DONE);
 354 }
 355
 356 void
 357 igmp_joingroup(struct in_multi *inm)
 358 {
 359         crit_enter();
 360         if (inm->inm_addr.s_addr == igmp_all_hosts_group
 361             || inm->inm_ifp->if_flags & IFF_LOOPBACK) {
 362                 inm->inm_timer = 0;
 363                 inm->inm_state = IGMP_OTHERMEMBER;
 364         } else {
 365                 inm->inm_rti = find_rti(inm->inm_ifp);
 366                 igmp_sendpkt(inm, inm->inm_rti->rti_type, 0);
 367                 inm->inm_timer = IGMP_RANDOM_DELAY(
 368                                         IGMP_MAX_HOST_REPORT_DELAY*PR_FASTHZ);
 369                 inm->inm_state = IGMP_IREPORTEDLAST;
 370                 igmp_timers_are_running = 1;
 371         }
 372         crit_exit();
 373 }
 374
 375 void
 376 igmp_leavegroup(struct in_multi *inm)
 377 {
 378         if (inm->inm_state == IGMP_IREPORTEDLAST &&
 379             inm->inm_addr.s_addr != igmp_all_hosts_group &&
 380             !(inm->inm_ifp->if_flags & IFF_LOOPBACK) &&
 381             inm->inm_rti->rti_type != IGMP_V1_ROUTER)
 382                 igmp_sendpkt(inm, IGMP_V2_LEAVE_GROUP, igmp_all_rtrs_group);
 383 }
 384
 385 static void
 386 igmp_fasttimo_ipi(void *arg __unused)
 387 {
 388         struct lwkt_msg *msg = &igmp_fasttimo_netmsg.lmsg;
 389
 390         crit_enter();
 391         if (msg->ms_flags & MSGF_DONE)
 392                 lwkt_sendmsg_oncpu(netisr_cpuport(0), msg);
 393         crit_exit();
 394 }
 395
 396 void
 397 igmp_fasttimo(void)
 398 {
 399         lwkt_send_ipiq_bycpu(0, igmp_fasttimo_ipi, NULL);
 400 }
 401
 402 static void
 403 igmp_fasttimo_dispatch(netmsg_t nmsg)
 404 {
 405         struct in_multi *inm;
 406         struct in_multistep step;
 407
 408         crit_enter();
 409         lwkt_replymsg(&nmsg->lmsg, 0);  /* reply ASAP */
 410         crit_exit();
 411
 412         /*
 413          * Quick check to see if any work needs to be done, in order
 414          * to minimize the overhead of fasttimo processing.
 415          */
 416
 417         if (!igmp_timers_are_running)
 418                 return;
 419
 420         igmp_timers_are_running = 0;
 421         IN_FIRST_MULTI(step, inm);
 422         while (inm != NULL) {
 423                 if (inm->inm_timer == 0) {
 424                         /* do nothing */
 425                 } else if (--inm->inm_timer == 0) {
 426                         igmp_sendpkt(inm, inm->inm_rti->rti_type, 0);
 427                         inm->inm_state = IGMP_IREPORTEDLAST;
 428                 } else {
 429                         igmp_timers_are_running = 1;
 430                 }
 431                 IN_NEXT_MULTI(step, inm);
 432         }
 433 }
 434
 435 static void
 436 igmp_slowtimo_ipi(void *arg __unused)
 437 {
 438         struct lwkt_msg *msg = &igmp_slowtimo_netmsg.lmsg;
 439
 440         crit_enter();
 441         if (msg->ms_flags & MSGF_DONE)
 442                 lwkt_sendmsg_oncpu(netisr_cpuport(0), msg);
 443         crit_exit();
 444 }
 445
 446 void
 447 igmp_slowtimo(void)
 448 {
 449         lwkt_send_ipiq_bycpu(0, igmp_slowtimo_ipi, NULL);
 450 }
 451
 452 static void
 453 igmp_slowtimo_dispatch(netmsg_t nmsg)
 454 {
 455         struct router_info *rti = Head;
 456
 457         crit_enter();
 458         lwkt_replymsg(&nmsg->lmsg, 0);  /* reply ASAP */
 459         crit_exit();
 460
 461 #ifdef IGMP_DEBUG
 462         kprintf("[igmp.c,_slowtimo] -- > entering \n");
 463 #endif
 464         while (rti) {
 465             if (rti->rti_type == IGMP_V1_ROUTER) {
 466                 rti->rti_time++;
 467                 if (rti->rti_time >= IGMP_AGE_THRESHOLD) {
 468                         rti->rti_type = IGMP_V2_ROUTER;
 469                 }
 470             }
 471             rti = rti->rti_next;
 472         }
 473 #ifdef IGMP_DEBUG
 474         kprintf("[igmp.c,_slowtimo] -- > exiting \n");
 475 #endif
 476 }
 477
 478 static struct route igmprt;
 479
 480 static void
 481 igmp_sendpkt(struct in_multi *inm, int type, unsigned long addr)
 482 {
 483         struct mbuf *m;
 484         struct igmp *igmp;
 485         struct ip *ip;
 486         struct ip_moptions imo;
 487
 488         MGETHDR(m, M_NOWAIT, MT_HEADER);
 489         if (m == NULL)
 490                 return;
 491
 492         m->m_pkthdr.rcvif = loif;
 493         m->m_pkthdr.len = sizeof(struct ip) + IGMP_MINLEN;
 494         MH_ALIGN(m, IGMP_MINLEN + sizeof(struct ip));
 495         m->m_data += sizeof(struct ip);
 496         m->m_len = IGMP_MINLEN;
 497         igmp = mtod(m, struct igmp *);
 498         igmp->igmp_type   = type;
 499         igmp->igmp_code   = 0;
 500         igmp->igmp_group  = inm->inm_addr;
 501         igmp->igmp_cksum  = 0;
 502         igmp->igmp_cksum  = in_cksum(m, IGMP_MINLEN);
 503
 504         m->m_data -= sizeof(struct ip);
 505         m->m_len += sizeof(struct ip);
 506         ip = mtod(m, struct ip *);
 507         ip->ip_tos = 0;
 508         ip->ip_len = sizeof(struct ip) + IGMP_MINLEN;
 509         ip->ip_off = 0;
 510         ip->ip_p = IPPROTO_IGMP;
 511         ip->ip_src.s_addr = INADDR_ANY;
 512         ip->ip_dst.s_addr = addr ? addr : igmp->igmp_group.s_addr;
 513
 514         imo.imo_multicast_ifp = inm->inm_ifp;
 515         imo.imo_multicast_ttl = 1;
 516         imo.imo_multicast_vif = -1;
 517         /*
 518          * Request loopback of the report if we are acting as a multicast
 519          * router, so that the process-level routing demon can hear it.
 520          */
 521         imo.imo_multicast_loop = (ip_mrouter != NULL);
 522
 523         /*
 524          * XXX
 525          * Do we have to worry about reentrancy here?  Don't think so.
 526          */
 527         ip_output(m, router_alert, &igmprt, 0, &imo, NULL);
 528
 529         ++igmpstat.igps_snd_reports;
 530 }