IPv6 next-hop with incorrect link-local address received

[Ondrej Zajicek]

On Fri, Aug 10, 2018 at 12:35:48PM +0200, Sebastian Neuner wrote:
> Hi all,
> 
> So now the next-hop in the BGP update looks like this:
> 
> >  Next hop network address (32 bytes)
> >    Next Hop: xxxx:xxxx:c02::28
> >    Next Hop: fe80::28a:96ff:fecc:c10
> 
> The GUA next-hop is correct and points to a VM on the server (i.e. not
> on the /127). The link-local next-hop points to the Cisco.
> Unfortunately, this is the one, bird uses to install the route in the
> kernel.
> 
> Am I missing something? Can I work around this somehow?

Perhaps you can use:

  gw = bgp_next_hop;

in import filter, which will set gateway based on GUA next-hop. And you
can use:

  bgp_next_hop = bgp_next_hop;

which will clear up link-local next hop (because bgp_next_hop in filters
only access the GUA part and resets link-local part when set).

-- 
Elen sila lumenn' omentielvo

Ondrej 'Santiago' Zajicek (email: santiago at crfreenet.org)
OpenPGP encrypted e-mails preferred (KeyID 0x11DEADC3, wwwkeys.pgp.net)
"To err is human -- to blame it on a computer is even more so."