/*------------------------------------------------------------------------
* icerrok - is it ok to send an error response?
*------------------------------------------------------------------------
*/
Bool
icerrok(struct ep *pep)
{
struct ip *pip = (struct ip *)pep->ep_data;
struct icmp *pic = (struct icmp *)pip->ip_data;
/* don't send errors about error packets... */
if (pip->ip_proto == IPT_ICMP)
switch(pic->ic_type) {
case ICT_DESTUR:
case ICT_REDIRECT:
case ICT_SRCQ:
case ICT_TIMEX:
case ICT_PARAMP:
return FALSE;
default:
break;
}
/* ...or other than the first of a fragment */
if (pip->ip_fragoff & IP_FRAGOFF)
return FALSE;
/* ...or broadcast or multicast packets */
if (isbrc(pip->ip_dst) || IP_CLASSD(pip->ip_dst))
return FALSE;
return TRUE;
}
/*------------------------------------------------------------------------
* 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;
}
