/*------------------------------------------------------------------------
* 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;
}
/*------------------------------------------------------------------------
* igmp_update - send (delayed) IGMP host group updates
*------------------------------------------------------------------------
*/
PROCESS
igmp_update(void)
{
struct hg *phg;
HostGroup.hi_uport = pcreate(HG_TSIZE);
while (1) {
phg = (struct hg *)preceive(HostGroup.hi_uport);
wait(HostGroup.hi_mutex);
if (phg->hg_state == HGS_DELAYING) {
phg->hg_state = HGS_IDLE;
igmp(IGT_HREPORT, phg->hg_ifnum, phg->hg_ipa);
}
signal(HostGroup.hi_mutex);
}
}
