This adds support for BGP RFC 5549 (Extended Next Hop Encoding capability)
* send and receive of the capability
* processing of IPv4->IPv6 next-hops
* for resolving these IPv6 next-hops, itsworks with the current
next-hop-tracking support
* added a new message type between BGP and Zebra for such route
install/uninstall
* zserv side of changes to process IPv4 prefix ->IPv6 next-hops
* required show command changes for IPv4 prefix having IPv6 next-hops
Few points to note about the implementation:
* It does an implicit next-hop-self when a [IPv4 prefix -> IPv6 LL next-hop]
is to be considered for advertisement to IPv4 peering (or IPv6 peering
without Extended next-hop capability negotiated)
* Currently feature is off by default, enable it by configuring
'neighbor <> capability extended-nexthop'
* Current support is for IPv4 Unicast prefixes only.
IMPORTANT NOTE:
This patch alone isn't enough to have IPv4->IPv6 routes installed into
the kernel. A separate patch is needed for that to work for the netlink
interface.
Signed-off-by: Vipin Kumar <vipin@cumulusnetworks.com> Reviewed-by: Daniel Walton <dwalton@cumulusnetworks.com>
Vivek Venkatraman <vivek@cumulusnetworks.com>
Donald Sharp <sharpd@cumulusnetworks.com>