Ignore NUD probe failure on incompleted IPv6 neighbors.
We often see the on-link IPv6 DNS server never responds to the multicast
NSes for address resolution often, although AP populates the RNDSS option
in RA, then device gets on-link IPv6 DNS server and send multicast NS to
query the link-layer address corresponding to on-link IPv6 global DNS
server address. If on-link IPv6 DNS server never respond to address
resolution, then we think that's not reachable and invoke reachability
failure then. To improve this situation, iff there is other available
DNS server in LinkProperties, we can try to ignore the NUD probe failure
and keep wifi still connected. Apply the same approach to IPv6 default
router neighbor, but the ignorance for incomplete IPv6 neighbors is
flag off by default.
Bug: 233684075
Bug: 249550357
Test: m NetworkStackIntegrationTests
Change-Id: I38785829188f62fd1d47142a641594a83ae91b5c
3 files changed
