igmp.rar_IGMP Linux_igmp

/* hgjoin.c - hgjoin */ #include <conf.h> #include <kernel.h> #include <network.h> #include <sleep.h> #include <igmp.h> /*------------------------------------------------------------------------ * hgjoin - handle application request to join a host group *------------------------------------------------------------------------ */ int hgjoin(unsigned ifnum, IPaddr ipa, Bool islocal) { struct hg *phg; int i; if (!IP_CLASSD(ipa)) return SYSERR; /* restrict multicast in multi-homed host to primary interface */ if (ifnum != NI_PRIMARY) return SYSERR; wait(HostGroup.hi_mutex); if (phg = hglookup(ifnum, ipa)) { phg->hg_refs++; signal(HostGroup.hi_mutex); return OK; /* already in it */ } signal(HostGroup.hi_mutex); /* add to host group and routing tables */ if (hgadd(ifnum, ipa, islocal) == SYSERR) return SYSERR; rtadd(ipa, ip_maskall, ipa, 0, NI_LOCAL, RT_INF); /* * advertise membership to multicast router(s); don't advertise * 224.0.0.1 (all multicast hosts) membership. */ if (ipa != ig_allhosts) for (i=0; i < IG_NSEND; ++i) { igmp(IGT_HREPORT, ifnum, ipa); sleep10(IG_DELAY); } return OK; }