[ source navigation ] [ diff markup ] [ identifier search ] [ freetext search ] [ file search ] [ list types ] [ track identifier ]

FreeBSD/Linux Kernel Cross Reference
sys/netinet/igmp.c

Version: -  FREEBSD  -  FREEBSD10  -  FREEBSD9  -  FREEBSD92  -  FREEBSD91  -  FREEBSD90  -  FREEBSD8  -  FREEBSD82  -  FREEBSD81  -  FREEBSD80  -  FREEBSD7  -  FREEBSD74  -  FREEBSD73  -  FREEBSD72  -  FREEBSD71  -  FREEBSD70  -  FREEBSD6  -  FREEBSD64  -  FREEBSD63  -  FREEBSD62  -  FREEBSD61  -  FREEBSD60  -  FREEBSD5  -  FREEBSD55  -  FREEBSD54  -  FREEBSD53  -  FREEBSD52  -  FREEBSD51  -  FREEBSD50  -  FREEBSD4  -  FREEBSD3  -  FREEBSD22  -  cheribsd  -  linux-2.6  -  linux-2.4.22  -  MK83  -  MK84  -  PLAN9  -  DFBSD  -  NETBSD  -  NETBSD5  -  NETBSD4  -  NETBSD3  -  NETBSD20  -  OPENBSD  -  xnu-517  -  xnu-792  -  xnu-792.6.70  -  xnu-1228  -  xnu-1456.1.26  -  xnu-1699.24.8  -  xnu-2050.18.24  -  OPENSOLARIS  -  minix-3-1-1  -  FREEBSD-LIBC  -  FREEBSD8-LIBC  -  FREEBSD7-LIBC  -  FREEBSD6-LIBC  -  GLIBC27 
SearchContext: -  none  -  3  -  10 

    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  * 4. 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  * $FreeBSD$
   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 "opt_mac.h"
   49 
   50 #include <sys/param.h>
   51 #include <sys/systm.h>
   52 #include <sys/mac.h>
   53 #include <sys/malloc.h>
   54 #include <sys/mbuf.h>
   55 #include <sys/socket.h>
   56 #include <sys/protosw.h>
   57 #include <sys/kernel.h>
   58 #include <sys/sysctl.h>
   59 
   60 #include <net/if.h>
   61 #include <net/route.h>
   62 
   63 #include <netinet/in.h>
   64 #include <netinet/in_var.h>
   65 #include <netinet/in_systm.h>
   66 #include <netinet/ip.h>
   67 #include <netinet/ip_var.h>
   68 #include <netinet/igmp.h>
   69 #include <netinet/igmp_var.h>
   70 
   71 #include <machine/in_cksum.h>
   72 
   73 static MALLOC_DEFINE(M_IGMP, "igmp", "igmp state");
   74 
   75 static struct router_info       *find_rti(struct ifnet *ifp);
   76 static void     igmp_sendpkt(struct in_multi *, int, unsigned long);
   77 
   78 static struct igmpstat igmpstat;
   79 
   80 SYSCTL_STRUCT(_net_inet_igmp, IGMPCTL_STATS, stats, CTLFLAG_RW, &igmpstat,
   81     igmpstat, "");
   82 
   83 /*
   84  * igmp_mtx protects all mutable global variables in igmp.c, as well as
   85  * the data fields in struct router_info.  In general, a router_info
   86  * structure will be valid as long as the referencing struct in_multi is
   87  * valid, so no reference counting is used.  We allow unlocked reads of
   88  * router_info data when accessed via an in_multi read-only.
   89  */
   90 static struct mtx igmp_mtx;
   91 static SLIST_HEAD(, router_info) router_info_head;
   92 static int igmp_timers_are_running;
   93 
   94 /*
   95  * XXXRW: can we define these such that these can be made const?  In any
   96  * case, these shouldn't be changed after igmp_init() and therefore don't
   97  * need locking.
   98  */
   99 static u_long igmp_all_hosts_group;
  100 static u_long igmp_all_rtrs_group;
  101 
  102 static struct mbuf *router_alert;
  103 static struct route igmprt;
  104 
  105 #ifdef IGMP_DEBUG
  106 #define IGMP_PRINTF(x)  printf(x)
  107 #else
  108 #define IGMP_PRINTF(x)
  109 #endif
  110 
  111 void
  112 igmp_init(void)
  113 {
  114         struct ipoption *ra;
  115 
  116         /*
  117          * To avoid byte-swapping the same value over and over again.
  118          */
  119         igmp_all_hosts_group = htonl(INADDR_ALLHOSTS_GROUP);
  120         igmp_all_rtrs_group = htonl(INADDR_ALLRTRS_GROUP);
  121 
  122         igmp_timers_are_running = 0;
  123 
  124         /*
  125          * Construct a Router Alert option to use in outgoing packets
  126          */
  127         MGET(router_alert, M_DONTWAIT, MT_DATA);
  128         ra = mtod(router_alert, struct ipoption *);
  129         ra->ipopt_dst.s_addr = 0;
  130         ra->ipopt_list[0] = IPOPT_RA;   /* Router Alert Option */
  131         ra->ipopt_list[1] = 0x04;       /* 4 bytes long */
  132         ra->ipopt_list[2] = 0x00;
  133         ra->ipopt_list[3] = 0x00;
  134         router_alert->m_len = sizeof(ra->ipopt_dst) + ra->ipopt_list[1];
  135 
  136         mtx_init(&igmp_mtx, "igmp_mtx", NULL, MTX_DEF);
  137         SLIST_INIT(&router_info_head);
  138 }
  139 
  140 static struct router_info *
  141 find_rti(struct ifnet *ifp)
  142 {
  143         struct router_info *rti;
  144 
  145         mtx_assert(&igmp_mtx, MA_OWNED);
  146         IGMP_PRINTF("[igmp.c, _find_rti] --> entering \n");
  147         SLIST_FOREACH(rti, &router_info_head, rti_list) {
  148                 if (rti->rti_ifp == ifp) {
  149                         IGMP_PRINTF(
  150                             "[igmp.c, _find_rti] --> found old entry \n");
  151                         return rti;
  152                 }
  153         }
  154         /*
  155          * XXXRW: return value of malloc not checked, despite M_NOWAIT.
  156          */
  157         MALLOC(rti, struct router_info *, sizeof *rti, M_IGMP, M_NOWAIT);
  158         rti->rti_ifp = ifp;
  159         rti->rti_type = IGMP_V2_ROUTER;
  160         rti->rti_time = 0;
  161         SLIST_INSERT_HEAD(&router_info_head, rti, rti_list);
  162 
  163         IGMP_PRINTF("[igmp.c, _find_rti] --> created an entry \n");
  164         return rti;
  165 }
  166 
  167 void
  168 igmp_input(register struct mbuf *m, int off)
  169 {
  170         register int iphlen = off;
  171         register struct igmp *igmp;
  172         register struct ip *ip;
  173         register int igmplen;
  174         register struct ifnet *ifp = m->m_pkthdr.rcvif;
  175         register int minlen;
  176         register struct in_multi *inm;
  177         register struct in_ifaddr *ia;
  178         struct in_multistep step;
  179         struct router_info *rti;
  180         int timer; /** timer value in the igmp query header **/
  181 
  182         ++igmpstat.igps_rcv_total;
  183 
  184         ip = mtod(m, struct ip *);
  185         igmplen = ip->ip_len;
  186 
  187         /*
  188          * Validate lengths
  189          */
  190         if (igmplen < IGMP_MINLEN) {
  191                 ++igmpstat.igps_rcv_tooshort;
  192                 m_freem(m);
  193                 return;
  194         }
  195         minlen = iphlen + IGMP_MINLEN;
  196         if ((m->m_flags & M_EXT || m->m_len < minlen) &&
  197             (m = m_pullup(m, minlen)) == 0) {
  198                 ++igmpstat.igps_rcv_tooshort;
  199                 return;
  200         }
  201 
  202         /*
  203          * Validate checksum
  204          */
  205         m->m_data += iphlen;
  206         m->m_len -= iphlen;
  207         igmp = mtod(m, struct igmp *);
  208         if (in_cksum(m, igmplen)) {
  209                 ++igmpstat.igps_rcv_badsum;
  210                 m_freem(m);
  211                 return;
  212         }
  213         m->m_data -= iphlen;
  214         m->m_len += iphlen;
  215 
  216         ip = mtod(m, struct ip *);
  217         timer = igmp->igmp_code * PR_FASTHZ / IGMP_TIMER_SCALE;
  218         if (timer == 0)
  219                 timer = 1;
  220 
  221         /*
  222          * In the IGMPv2 specification, there are 3 states and a flag.
  223          *
  224          * In Non-Member state, we simply don't have a membership record.
  225          * In Delaying Member state, our timer is running (inm->inm_timer)
  226          * In Idle Member state, our timer is not running (inm->inm_timer==0)
  227          *
  228          * The flag is inm->inm_state, it is set to IGMP_OTHERMEMBER if
  229          * we have heard a report from another member, or IGMP_IREPORTEDLAST
  230          * if I sent the last report.
  231          */
  232         switch (igmp->igmp_type) {
  233         case IGMP_MEMBERSHIP_QUERY:
  234                 ++igmpstat.igps_rcv_queries;
  235 
  236                 if (ifp->if_flags & IFF_LOOPBACK)
  237                         break;
  238 
  239                 if (igmp->igmp_code == 0) {
  240                         /*
  241                          * Old router.  Remember that the querier on this
  242                          * interface is old, and set the timer to the
  243                          * value in RFC 1112.
  244                          */
  245 
  246                         mtx_lock(&igmp_mtx);
  247                         rti = find_rti(ifp);
  248                         rti->rti_type = IGMP_V1_ROUTER;
  249                         rti->rti_time = 0;
  250                         mtx_unlock(&igmp_mtx);
  251 
  252                         timer = IGMP_MAX_HOST_REPORT_DELAY * PR_FASTHZ;
  253 
  254                         if (ip->ip_dst.s_addr != igmp_all_hosts_group ||
  255                             igmp->igmp_group.s_addr != 0) {
  256                                 ++igmpstat.igps_rcv_badqueries;
  257                                 m_freem(m);
  258                                 return;
  259                         }
  260                 } else {
  261                         /*
  262                          * New router.  Simply do the new validity check.
  263                          */
  264                         
  265                         if (igmp->igmp_group.s_addr != 0 &&
  266                             !IN_MULTICAST(ntohl(igmp->igmp_group.s_addr))) {
  267                                 ++igmpstat.igps_rcv_badqueries;
  268                                 m_freem(m);
  269                                 return;
  270                         }
  271                 }
  272 
  273                 /*
  274                  * - Start the timers in all of our membership records
  275                  *   that the query applies to for the interface on
  276                  *   which the query arrived excl. those that belong
  277                  *   to the "all-hosts" group (224.0.0.1).
  278                  * - Restart any timer that is already running but has
  279                  *   a value longer than the requested timeout.
  280                  * - Use the value specified in the query message as
  281                  *   the maximum timeout.
  282                  */
  283                 IN_MULTI_LOCK();
  284                 IN_FIRST_MULTI(step, inm);
  285                 while (inm != NULL) {
  286                         if (inm->inm_ifp == ifp &&
  287                             inm->inm_addr.s_addr != igmp_all_hosts_group &&
  288                             (igmp->igmp_group.s_addr == 0 ||
  289                              igmp->igmp_group.s_addr == inm->inm_addr.s_addr)) {
  290                                 if (inm->inm_timer == 0 ||
  291                                     inm->inm_timer > timer) {
  292                                         inm->inm_timer =
  293                                                 IGMP_RANDOM_DELAY(timer);
  294                                         igmp_timers_are_running = 1;
  295                                 }
  296                         }
  297                         IN_NEXT_MULTI(step, inm);
  298                 }
  299                 IN_MULTI_UNLOCK();
  300 
  301                 break;
  302 
  303         case IGMP_V1_MEMBERSHIP_REPORT:
  304         case IGMP_V2_MEMBERSHIP_REPORT:
  305                 /*
  306                  * For fast leave to work, we have to know that we are the
  307                  * last person to send a report for this group.  Reports
  308                  * can potentially get looped back if we are a multicast
  309                  * router, so discard reports sourced by me.
  310                  */
  311                 IFP_TO_IA(ifp, ia);
  312                 if (ia && ip->ip_src.s_addr == IA_SIN(ia)->sin_addr.s_addr)
  313                         break;
  314 
  315                 ++igmpstat.igps_rcv_reports;
  316 
  317                 if (ifp->if_flags & IFF_LOOPBACK)
  318                         break;
  319 
  320                 if (!IN_MULTICAST(ntohl(igmp->igmp_group.s_addr))) {
  321                         ++igmpstat.igps_rcv_badreports;
  322                         m_freem(m);
  323                         return;
  324                 }
  325 
  326                 /*
  327                  * KLUDGE: if the IP source address of the report has an
  328                  * unspecified (i.e., zero) subnet number, as is allowed for
  329                  * a booting host, replace it with the correct subnet number
  330                  * so that a process-level multicast routing daemon can
  331                  * determine which subnet it arrived from.  This is necessary
  332                  * to compensate for the lack of any way for a process to
  333                  * determine the arrival interface of an incoming packet.
  334                  */
  335                 if ((ntohl(ip->ip_src.s_addr) & IN_CLASSA_NET) == 0)
  336                         if (ia) ip->ip_src.s_addr = htonl(ia->ia_subnet);
  337 
  338                 /*
  339                  * If we belong to the group being reported, stop
  340                  * our timer for that group.
  341                  */
  342                 IN_MULTI_LOCK();
  343                 IN_LOOKUP_MULTI(igmp->igmp_group, ifp, inm);
  344                 if (inm != NULL) {
  345                         inm->inm_timer = 0;
  346                         ++igmpstat.igps_rcv_ourreports;
  347 
  348                         inm->inm_state = IGMP_OTHERMEMBER;
  349                 }
  350                 IN_MULTI_UNLOCK();
  351 
  352                 break;
  353         }
  354 
  355         /*
  356          * Pass all valid IGMP packets up to any process(es) listening
  357          * on a raw IGMP socket.
  358          */
  359         rip_input(m, off);
  360 }
  361 
  362 void
  363 igmp_joingroup(struct in_multi *inm)
  364 {
  365 
  366         IN_MULTI_LOCK_ASSERT();
  367 
  368         if (inm->inm_addr.s_addr == igmp_all_hosts_group
  369             || inm->inm_ifp->if_flags & IFF_LOOPBACK) {
  370                 inm->inm_timer = 0;
  371                 inm->inm_state = IGMP_OTHERMEMBER;
  372         } else {
  373                 mtx_lock(&igmp_mtx);
  374                 inm->inm_rti = find_rti(inm->inm_ifp);
  375                 mtx_unlock(&igmp_mtx);
  376                 igmp_sendpkt(inm, inm->inm_rti->rti_type, 0);
  377                 inm->inm_timer = IGMP_RANDOM_DELAY(
  378                                         IGMP_MAX_HOST_REPORT_DELAY*PR_FASTHZ);
  379                 inm->inm_state = IGMP_IREPORTEDLAST;
  380                 igmp_timers_are_running = 1;
  381         }
  382 }
  383 
  384 void
  385 igmp_leavegroup(struct in_multi *inm)
  386 {
  387 
  388         IN_MULTI_LOCK_ASSERT();
  389 
  390         if (inm->inm_state == IGMP_IREPORTEDLAST &&
  391             inm->inm_addr.s_addr != igmp_all_hosts_group &&
  392             !(inm->inm_ifp->if_flags & IFF_LOOPBACK) &&
  393             inm->inm_rti->rti_type != IGMP_V1_ROUTER)
  394                 igmp_sendpkt(inm, IGMP_V2_LEAVE_GROUP, igmp_all_rtrs_group);
  395 }
  396 
  397 void
  398 igmp_fasttimo(void)
  399 {
  400         register struct in_multi *inm;
  401         struct in_multistep step;
  402 
  403         /*
  404          * Quick check to see if any work needs to be done, in order
  405          * to minimize the overhead of fasttimo processing.
  406          */
  407 
  408         if (!igmp_timers_are_running)
  409                 return;
  410 
  411         IN_MULTI_LOCK();
  412         igmp_timers_are_running = 0;
  413         IN_FIRST_MULTI(step, inm);
  414         while (inm != NULL) {
  415                 if (inm->inm_timer == 0) {
  416                         /* do nothing */
  417                 } else if (--inm->inm_timer == 0) {
  418                         igmp_sendpkt(inm, inm->inm_rti->rti_type, 0);
  419                         inm->inm_state = IGMP_IREPORTEDLAST;
  420                 } else {
  421                         igmp_timers_are_running = 1;
  422                 }
  423                 IN_NEXT_MULTI(step, inm);
  424         }
  425         IN_MULTI_UNLOCK();
  426 }
  427 
  428 void
  429 igmp_slowtimo(void)
  430 {
  431         struct router_info *rti;
  432 
  433         IGMP_PRINTF("[igmp.c,_slowtimo] -- > entering \n");
  434         mtx_lock(&igmp_mtx);
  435         SLIST_FOREACH(rti, &router_info_head, rti_list) {
  436                 if (rti->rti_type == IGMP_V1_ROUTER) {
  437                         rti->rti_time++;
  438                         if (rti->rti_time >= IGMP_AGE_THRESHOLD)
  439                                 rti->rti_type = IGMP_V2_ROUTER;
  440                 }
  441         }
  442         mtx_unlock(&igmp_mtx);
  443         IGMP_PRINTF("[igmp.c,_slowtimo] -- > exiting \n");
  444 }
  445 
  446 static void
  447 igmp_sendpkt(struct in_multi *inm, int type, unsigned long addr)
  448 {
  449         struct mbuf *m;
  450         struct igmp *igmp;
  451         struct ip *ip;
  452         struct ip_moptions imo;
  453 
  454         IN_MULTI_LOCK_ASSERT();
  455 
  456         MGETHDR(m, M_DONTWAIT, MT_HEADER);
  457         if (m == NULL)
  458                 return;
  459 
  460         m->m_pkthdr.rcvif = loif;
  461 #ifdef MAC
  462         mac_create_mbuf_linklayer(inm->inm_ifp, m);
  463 #endif
  464         m->m_pkthdr.len = sizeof(struct ip) + IGMP_MINLEN;
  465         MH_ALIGN(m, IGMP_MINLEN + sizeof(struct ip));
  466         m->m_data += sizeof(struct ip);
  467         m->m_len = IGMP_MINLEN;
  468         igmp = mtod(m, struct igmp *);
  469         igmp->igmp_type = type;
  470         igmp->igmp_code = 0;
  471         igmp->igmp_group = inm->inm_addr;
  472         igmp->igmp_cksum = 0;
  473         igmp->igmp_cksum = in_cksum(m, IGMP_MINLEN);
  474 
  475         m->m_data -= sizeof(struct ip);
  476         m->m_len += sizeof(struct ip);
  477         ip = mtod(m, struct ip *);
  478         ip->ip_tos = 0;
  479         ip->ip_len = sizeof(struct ip) + IGMP_MINLEN;
  480         ip->ip_off = 0;
  481         ip->ip_p = IPPROTO_IGMP;
  482         ip->ip_src.s_addr = INADDR_ANY;
  483         ip->ip_dst.s_addr = addr ? addr : igmp->igmp_group.s_addr;
  484 
  485         imo.imo_multicast_ifp  = inm->inm_ifp;
  486         imo.imo_multicast_ttl  = 1;
  487         imo.imo_multicast_vif  = -1;
  488         /*
  489          * Request loopback of the report if we are acting as a multicast
  490          * router, so that the process-level routing daemon can hear it.
  491          */
  492         imo.imo_multicast_loop = (ip_mrouter != NULL);
  493 
  494         /*
  495          * XXX
  496          * Do we have to worry about reentrancy here?  Don't think so.
  497          */
  498         ip_output(m, router_alert, &igmprt, 0, &imo, NULL);
  499 
  500         ++igmpstat.igps_snd_reports;
  501 }

Cache object: 01c9ea8dd3c4395d0df4f90166a0b431


[ source navigation ] [ diff markup ] [ identifier search ] [ freetext search ] [ file search ] [ list types ] [ track identifier ]


This page is part of the FreeBSD/Linux Linux Kernel Cross-Reference, and was automatically generated using a modified version of the LXR engine.