[SAM] detect the presence of an IGMPv3 querier

[Sebastian Wölke <[e-mail]>]

Hi all,

I'm working on a system software that automatically detects the presence
of a multicast querier in the current subnet based on passively
monitoring Linux kernel states.

This works fine for IPv6/MLD by looking into the /proc/net/SNMP6 table.
For IPv4/IGMP, the SNMP approach does not work. I can detect an IGMPv2
querier by monitoring 'Timer' in the /proc/net/igmp table: this counts
down the [Unsolicited Report Interval]. However, this does not exist for
IGMPv3, as reports are not suppressed.

My question is about IGMPv3. Does anybody know how to detect the
presence of an IGMPv3 querier based on the kernel states of a multicast
client?

Thanks for your support,

Sebastian