Hi BIRD-Users, I just got into a situation here... I reconfigured my bird (with some new filter rules on BGP), but now some peerings don't come up anymore: bird> show protocols R8596x130 name proto table state since info R8596x130 BGP T8596x130 start 12:03 Idle Received: Malformed attribute list All I see in the logs is: Apr 8 12:04:54 rs2 bird: R8596x130: Connected to table T8596x130 Apr 8 12:04:54 rs2 bird: R8596x130: State changed to up Apr 8 12:04:54 rs2 bird: R8596x130: Received: Malformed attribute list: c00800 Apr 8 12:04:54 rs2 bird: R8596x130: BGP session closed I beg for your help! Wolfgang -- www.vix.at | www.aco.net wh@univie.ac.at | WH844-RIPE Vienna University Computer Center
Allright, reply to myself: This seems to be a bug in BIRD. What I actually added was a rule that certain communities should be deleted: if ((1120,1)) ~ bgp_community then bgp_community.delete((1120,1)); this actually seemed to delete the only community attached to a certain prefix, which led to a bgp announcement that contained the community attribute which was in fact empty. this causes some cisco routers to throw up on the bgp session. So I think this is a bug in BIRD - if the last community is deleted on a prefix, the community tag must no longer be attached to the prefix. What do you think? Are there any chances you could fix this in the coming update? Wolfgang On Apr 8, 2010, at 14:05 , Wolfgang Hennerbichler wrote:
Hi BIRD-Users,
I just got into a situation here... I reconfigured my bird (with some new filter rules on BGP), but now some peerings don't come up anymore:
bird> show protocols R8596x130 name proto table state since info R8596x130 BGP T8596x130 start 12:03 Idle
On Thu, Apr 08, 2010 at 02:44:11PM +0200, Wolfgang Hennerbichler wrote:
Allright, reply to myself:
This seems to be a bug in BIRD. What I actually added was a rule that certain communities should be deleted: if ((1120,1)) ~ bgp_community then bgp_community.delete((1120,1));
this actually seemed to delete the only community attached to a certain prefix, which led to a bgp announcement that contained the community attribute which was in fact empty. this causes some cisco routers to throw up on the bgp session. So I think this is a bug in BIRD - if the last community is deleted on a prefix, the community tag must no longer be attached to the prefix. What do you think? Are there any chances you could fix this in the coming update?
Hello. Thank you for the bug report. The RFC 1997 does not explicitly forbid empty community attribute and we assumed that it is valid. But if some Cisco routers don't like it reasonable to not generate such attribute. I fixed it in dev version and the fix will be in coming update. -- Elen sila lumenn' omentielvo Ondrej 'SanTiago' Zajicek (email: santiago@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."
On Apr 9, 2010, at 10:08 , Ondrej Zajicek wrote:
Hello.
Hi,
Thank you for the bug report.
No problem.
The RFC 1997 does not explicitly forbid empty community attribute and we assumed that it is valid. But if some Cisco routers don't like it reasonable to not generate such attribute. I fixed it in dev version and the fix will be in coming update.
Great news. Actually I think every cisco router threw up, JunOS didn't seem to care (I think). BTW: What happens if I do a bgp_community.delete ((1234,1234)) if the community doesn't exist?
-- Elen sila lumenn' omentielvo
Ondrej 'SanTiago' Zajicek (email: santiago@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."
-- www.vix.at | www.aco.net wh@univie.ac.at | WH844-RIPE Vienna University Computer Center
On Fri, Apr 09, 2010 at 10:09:22AM +0200, Wolfgang Hennerbichler wrote:
Great news. Actually I think every cisco router threw up, JunOS didn't seem to care (I think). BTW: What happens if I do a bgp_community.delete ((1234,1234)) if the community doesn't exist?
It does nothing (with the exception that if there is no community attribute, it creates the empty one). -- Elen sila lumenn' omentielvo Ondrej 'SanTiago' Zajicek (email: santiago@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."
On Apr 9, 2010, at 10:43 , Ondrej Zajicek wrote:
On Fri, Apr 09, 2010 at 10:09:22AM +0200, Wolfgang Hennerbichler wrote:
Great news. Actually I think every cisco router threw up, JunOS didn't seem to care (I think). BTW: What happens if I do a bgp_community.delete ((1234,1234)) if the community doesn't exist?
It does nothing (with the exception that if there is no community attribute, it creates the empty one).
good, except for the latter, this is my expected behaviour.
-- Elen sila lumenn' omentielvo
Ondrej 'SanTiago' Zajicek (email: santiago@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."
-- www.vix.at | www.aco.net wh@univie.ac.at | WH844-RIPE Vienna University Computer Center
participants (2)
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Ondrej Zajicek -
Wolfgang Hennerbichler