netdev - Re: VRF leaking doesn't work

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Message-ID: <5f673241-9cb1-eb36-be9a-a82b0174bd9c@gmail.com>
Date:   Fri, 12 Mar 2021 09:39:05 -0700
From:   David Ahern <dsahern@...il.com>
To:     Greesha Mikhalkin <grigoriymikhalkin@...il.com>
Cc:     netdev@...r.kernel.org
Subject: Re: VRF leaking doesn't work

On 3/10/21 1:34 AM, Greesha Mikhalkin wrote:
> I see. When i do `ping -I vrf2` to address that was leaked from vrf1
> it selects source address that's set as local in vrf1 routing table.
> Is this expected behavior? I guess, forwarding packets from vrf1 to
> vrf2 local address won't help here.
> 

That's the way the source address selection works -- it takes the fib
lookup result and finds the best source address match for it.

Try adding 'src a.b.c.d' to the leaked route. e.g.,
    ip ro add 172.16.1.0/24 dev red vrf blue src 172.16.2.1

where red and blue are VRFs, 172.16.2.1 is a valid source address in VRF
blue and VRF red has the reverse route installed.