On Mon, Apr 18, 2022 at 04:43:32AM +0200, Alexander Zubkov wrote: > For example bird can check that the hold timer proposed by a peer is > at least 2 times greater than the local keepalive timer as in the > attached patch.
Hi Thanks for the patch. You are right, it would be a good idea to check the hold time against the configured keepalive time. It is a question where to put the cutoff, as technically even longer keepalive intervals (than half of hold times) are viable, so in corner cases it may break some working setups. I think that rejecting session when hold timer is smaller than local keepalive (so it is clear misconfiguration), and just a warning when it is smaller than 2*keepalive would be a good approach. Will look at that. > On Mon, Apr 11, 2022 at 1:12 PM Alexander Zubkov <gr...@qrator.net> wrote: > > > > Hi, > > > > Found interesting thing. If I set "keepalive time" for a BGP session, > > this values is not modified after the hold time negotiations and as a > > result I can get a BGP session with hold timer less than keepalive > > timer and it will die due to hold timer expired after some time. > > https://gitlab.nic.cz/labs/bird/-/blob/692055e3df6cc9f0d428d3b0dd8cdd8e825eb6f4/proto/bgp/packets.c#L908 > > I think more correct bahivour would be to close the BGP session with > > unacceptable hold timer error in such case. -- 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."
