[PATCH] babel: Keep separate auth PC counters for unicast and multicast

Ondrej Zajicek santiago at crfreenet.org
Tue Jan 24 18:40:38 CET 2023


On Tue, Jan 24, 2023 at 12:12:19AM +0100, Toke Høiland-Jørgensen via Bird-users wrote:
> The issue has been described in draft-ietf-babel-mac-relaxed, which is
> currently pending RFC publication. That also describes two mitigation
> mechanisms: Keeping separate PC counters for unicast and multicast, and
> using a reorder window for PC values. This patch implements the former as
> that is the simplest, and resolves the particular issue seen on WiFi.

Hi

Is that sufficient? In general, one should not assume anything about link
frame ordering. Even two unicast (or two multicast) packets can be
reordered due to e.g. frame retransmission.

I think that simple sequence numbers work in two cases - if there is
sufficient interval between packets, or there is only one packet flying
(e.g. LSREQ-LSUPD ping-pong in OSPF). That is approach used in OSPFv2 and
OSPFv3, but that is not true in Babel.

-- 
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."



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