On Wed, 2019-11-13 at 16:48 +0100, Matthieu Baerts wrote:
<On 12/11/2019 09:21, Paolo Abeni wrote:
> 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
When you say that the option is omitted, do you mean that the option is
sent in the new (dedicated?) ACK packet or dropped/never sent? :)
With the current code, prior to this series, the ADD/DEL_ADDR option
exceeding the TCP option space is dropped/never sent. This series do
not change such behavior.
Inserting a (duplicate) ack to try to fit such option looks doable, but
also out-of-scope for this change.