[magma] IGMPv2 query processing by a v1 stack

[Subrata Sa <kiteflyer77 at gmail.com>]

Hello,

An IGMPv1 stack has joined groups G1, G2 and G3 and it has received an
IGMPv2 group (G1) specific query where none of the groups is "all
hosts group". I can think of following possibilities as how the stack
can handle the Query:

1. Process it as an IGMPv1 general query

As per RFC 1112 (pages 11, 12)
"
Group Address
In a Host Membership Query message, the group address field is zeroed
when sent, ignored when received. (B)
"

So the IGMPv2 Query packet is treated as a general query and reports
for ALL groups are sent.

Cons: Groups (G2, G3) that are not queried are being reported.

2. Send report for only group G1

Cons: any?

3. Drop it

Cons: Router/ snooping switch cannot refresh its forwarding state for
group G1 though sending a periodic v2 general query would do so.

I'm tempted to go for the 3rd option. What to you think?

-Subrata