bgpd: Make source interface selection in BGP for nexthop determination more robust

Ensure that if 'update-source <interface>' is specified, that interface is
chosen as the source for the local nexthops. Otherwise, do a complete
match on the local IP address of the connection to determine the source
interface for the local nexthops; this will handle scenarios where there
is an overlap of subnets between interfaces (e.g., loopback and another
interface).

Signed-off-by: Vivek Venkatraman <vivek@cumulusnetworks.com>
1 file changed