ipv6: adjust MLD membership on address state changes

If MLD support is enabled, each locally assigned IPv6 address in the
appropriate state must be a member of the solicited-node multicast
group corresponding to that address.  Ensure that this is always the
case by (re-)deciding on the membership upon every address state
change.  By doing so, this patch enforces that user-initiated state
changes to addresses (e.g., deletion) never cause a desynchronization
with the corresponding solicited-node multicast group membership,
thereby making such user-initiated state changes simpler and safer.
3 files changed