unimore/kernel-hacking-2024-linux-steffo
unimore/kernel-hacking-2024-linux-steffo
1
Fork 0
Code Pull requests 5 Wiki Activity

mptcp: fully established after ADD_ADDR echo on MPJ

Browse source 
Before this patch, receiving an ADD_ADDR echo on the just connected
MP_JOIN subflow -- initiator side, after the MP_JOIN 3WHS -- was
resulting in an MP_RESET. That's because only ACKs with a DSS or
ADD_ADDRs without the echo bit were allowed.

Not allowing the ADD_ADDR echo after an MP_CAPABLE 3WHS makes sense, as
we are not supposed to send an ADD_ADDR before because it requires to be
in full established mode first. For the MP_JOIN 3WHS, that's different:
the ADD_ADDR can be sent on a previous subflow, and the ADD_ADDR echo
can be received on the recently created one. The other peer will already
be in fully established, so it is allowed to send that.

We can then relax the conditions here to accept the ADD_ADDR echo for
MPJ subflows.

Fixes: 67b12f792d ("mptcp: full fully established support after ADD_ADDR")
Cc: stable@vger.kernel.org
Reviewed-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://patch.msgid.link/20240731-upstream-net-20240731-mptcp-endp-subflow-signal-v1-1-c8a9b036493b@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Matthieu Baerts (NGI0) 2024-07-31 13:05:53 +02:00 committed by Jakub Kicinski
parent 183d46ff42
commit d67c5649c1
1 changed files with 2 additions and 1 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

3
net/mptcp/options.c
View file

@ -958,7 +958,8 @@ static bool check_fully_established(struct mptcp_sock *msk, struct sock *ssk,
if (subflow->remote_key_valid &&
(((mp_opt->suboptions & OPTION_MPTCP_DSS) && mp_opt->use_ack) ||
((mp_opt->suboptions & OPTION_MPTCP_ADD_ADDR) && !mp_opt->echo))) {
((mp_opt->suboptions & OPTION_MPTCP_ADD_ADDR) &&
(!mp_opt->echo || subflow->mp_join)))) {
/* subflows are fully established as soon as we get any
* additional ack, including ADD_ADDR.
*/