8:21 a.m.
On Mon, 2019-11-11 at 13:50 -0800, Peter Krystad wrote:
Hi Paolo -
On Mon, 2019-11-11 at 17:53 +0100, Paolo Abeni wrote:
> since such option will always fit the tcp header, module bugs.
"modulo"
thnx! Hopefully comment should be dropped when squashing ;)
How is it guaranteed that it will always fit, now and in the future?
TCP option space must accomodate tstamp (12 bytes) and MPTCP options.
AFAICS DSS, MP_CAPABLE and MP_JOIN are mutually esclusive, and the
bigger is DSS with 64 bytes ack/seq and csum with a total of 28 bytes -
which fit the TCP option space.
Additional MPTCP options (ADD/DEL_ADDR/PRIO/FAIL/FASTCLOSE/...) can
indeed run out of space, but that failure is not fatal (do not break
the connection nor causes fallback) and is handled gracefully - no
WARN, just omit the option. Additionally we could increment some MIB
counter.
Thanks,
Paolo