Re: [PATCH 5.15.y] mptcp: fully established after ADD_ADDR echo on MPJ

[Greg KH <gregkh@linuxfoundation.org>]

On Tue, Aug 13, 2024 at 12:46:43PM +0200, Matthieu Baerts (NGI0) wrote:
> commit d67c5649c1541dc93f202eeffc6f49220a4ed71d upstream.
> 
> 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: 67b12f792d5e ("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>
> [ Conflicts in options.c, because the context has changed in commit
>   b3ea6b272d79 ("mptcp: consolidate initial ack seq generation"), which
>   is not in this version. This commit is unrelated to this
>   modification. ]
> Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
> ---
>  net/mptcp/options.c | 3 ++-

Now queued up, thanks.

greg k-h