itojun 1cc58965b6 don't panic when there's no interface address exist for the specified multicast
outgoing interface (ia == NULL after IFP_TO_IA).

historic behavior (up to revision 1.43) was to use 0.0.0.0 as source address,
but it seems like a mistake according to RFC1112/1122.
2002-01-08 10:05:13 +00:00
..