Re: RFC 5575 question: is Destination Prefix mendatory?

[Alarig Le Lay]

On Tue 21 Apr 2020 18:08:17 GMT, Ondrej Zajicek wrote:
> Hi
> 
> See https://bird.network.cz/pipermail/bird-users/2020-February/014220.html
> 
> Fixed in commit 78e4a123bb937bb45f7eaebb0ea475095443bfd0

I didn’t see the previous message, sorry. I made a package based on this
commit and it works, thank you very much :)

-- 
Alarig

Re: RFC 5575 question: is Destination Prefix mendatory?

[Ondrej Zajicek]

On Tue, Apr 21, 2020 at 05:50:50PM +0200, Alarig Le Lay wrote:
> Hi,
> 
> it seems that for bird, the flowspec destination prefix is mentatory. I
> have a session with an exabgp and if I send this
>   echo 'announce flow route { match { source 213.167.241.55/32; 
> destination 0.0.0.0/0; } then { discard; } }' > /var/run/exabgp.cmd
> It works, I have the route:

Hi

See https://bird.network.cz/pipermail/bird-users/2020-February/014220.html

Fixed in commit 78e4a123bb937bb45f7eaebb0ea475095443bfd0

-- 
Elen sila lumenn' omentielvo

Ondrej 'Santiago' Zajicek (email: santi...@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."

RFC 5575 question: is Destination Prefix mendatory?

[Alarig Le Lay]

Hi,

it seems that for bird, the flowspec destination prefix is mentatory. I
have a session with an exabgp and if I send this
echo 'announce flow route { match { source 213.167.241.55/32; 
destination 0.0.0.0/0; } then { discard; } }' > /var/run/exabgp.cmd
It works, I have the route:

bird> show route all table flowtab4
Table flowtab4:
flow4 { dst 0.0.0.0/0; src 213.167.241.55/32; }  [bgp_wfiltr1_ipv4 
15:44:14.440 from 217.70.176.118] * (100) [i]
Type: BGP univ
BGP.origin: IGP
BGP.as_path:
BGP.local_pref: 100
BGP.ext_community: (generic, 0x8006, 0x0)

But, if I send this:
echo 'announce flow route { match { source 213.167.241.55/32; } then { 
discard; } }' > /var/run/exabgp.cmd
It doesn’t work, the session is in error state (BGP Error: Malformed
attribute list) and the log says "Invalid flow route: Destination prefix
is missing".

However, https://tools.ietf.org/html/rfc5575#section-4 says
   We define a "Flow Specification" NLRI type that may include several
   components such as destination prefix, source prefix, protocol,
   ports, etc.  This NLRI is treated as an opaque bit string prefix by
   BGP.  Each bit string identifies a key to a database entry with which
   a set of attributes can be associated.

As it’s “may”, I would say that it’s not mendatory. The sessions toward
ASR9K routers accept the annoucement.

Regards,
-- 
Alarig