From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A67593081A9 for ; Mon, 27 Oct 2025 15:34:54 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761579294; cv=none; b=uhFO39oDXvE0FKcf4Ib7cBygXBwsxsP0bLeNQTIVoMdHWY5K3DirEgXN49R7BKHIFJRIXmPEqyuTOysx3vpWdslfKg6Vn65lqFqJHSObe8kp9NEOUZTs1L4KpA7Py8jn/qsvgslYSQC9KLvwjhxpAMIl26CA401nc8HP5lOtHKs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761579294; c=relaxed/simple; bh=10p6uTgcw3AoRxQrOgez8FotQiOoe0tXZNMRbJV4cTQ=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Ly7D0VbTGAh0yhocI8VHQqnvwH/DbKo65FMcT2firFML+maIuvVnUzYP6V3eCcQJiSpZngKelCNXF+c/DQfY49RxGfKGLEBRfg2QlokVg79dQvAXBJKSWjPxanModF9R3WGIHPS4XXAarfHZxLeNiC/RtphlPkM/MKkYsqg70oY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=AcUmyuBL; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="AcUmyuBL" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 75199C4CEF1; Mon, 27 Oct 2025 15:34:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1761579294; bh=10p6uTgcw3AoRxQrOgez8FotQiOoe0tXZNMRbJV4cTQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=AcUmyuBLNhueV8ChZKxZS1TqnR8hPlXEG7a8tMNZwdtF+NHi+pK45ZpXfaFR0uxD5 1U/emoEQRMEWncis99ofporasqQ4kdhPPbBupggVAE1gHNujAGmP+oevdUafgx6b8W RCG0sbvIq6a2SYg77/ynKZYmdJ071ErahQj4kgXVWbEHpxltm7ZWu/92pQTWaH2aSF qypVeTBvIjKXNy11qwxyGzsQVX6K9vZTd5Ezgcm04JzpIMIccbJcKJDcIOLB+rvzAY XgnHW5qzLK34uq3XNJbkbXtbW5HY2X5VhAAwnmUX58nL/JTvVVHeNOYUsx/aurefyQ D5WS0Msx3qaTw== From: Sasha Levin To: stable@vger.kernel.org Cc: "Matthieu Baerts (NGI0)" , Geliang Tang , Jakub Kicinski , Sasha Levin Subject: [PATCH 6.12.y] mptcp: pm: in-kernel: C-flag: handle late ADD_ADDR Date: Mon, 27 Oct 2025 11:34:51 -0400 Message-ID: <20251027153451.554067-1-sashal@kernel.org> X-Mailer: git-send-email 2.51.0 In-Reply-To: <2025102634-cache-seventeen-becb@gregkh> References: <2025102634-cache-seventeen-becb@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: "Matthieu Baerts (NGI0)" [ Upstream commit e84cb860ac3ce67ec6ecc364433fd5b412c448bc ] The special C-flag case expects the ADD_ADDR to be received when switching to 'fully-established'. But for various reasons, the ADD_ADDR could be sent after the "4th ACK", and the special case doesn't work. On NIPA, the new test validating this special case for the C-flag failed a few times, e.g. 102 default limits, server deny join id 0 syn rx [FAIL] got 0 JOIN[s] syn rx expected 2 Server ns stats (...) MPTcpExtAddAddrTx 1 MPTcpExtEchoAdd 1 Client ns stats (...) MPTcpExtAddAddr 1 MPTcpExtEchoAddTx 1 synack rx [FAIL] got 0 JOIN[s] synack rx expected 2 ack rx [FAIL] got 0 JOIN[s] ack rx expected 2 join Rx [FAIL] see above syn tx [FAIL] got 0 JOIN[s] syn tx expected 2 join Tx [FAIL] see above I had a suspicion about what the issue could be: the ADD_ADDR might have been received after the switch to the 'fully-established' state. The issue was not easy to reproduce. The packet capture shown that the ADD_ADDR can indeed be sent with a delay, and the client would not try to establish subflows to it as expected. A simple fix is not to mark the endpoints as 'used' in the C-flag case, when looking at creating subflows to the remote initial IP address and port. In this case, there is no need to try. Note: newly added fullmesh endpoints will still continue to be used as expected, thanks to the conditions behind mptcp_pm_add_addr_c_flag_case. Fixes: 4b1ff850e0c1 ("mptcp: pm: in-kernel: usable client side with C-flag") Cc: stable@vger.kernel.org Reviewed-by: Geliang Tang Signed-off-by: Matthieu Baerts (NGI0) Link: https://patch.msgid.link/20251020-net-mptcp-c-flag-late-add-addr-v1-1-8207030cb0e8@kernel.org Signed-off-by: Jakub Kicinski [ applied to pm_netlink.c instead of pm_kernel.c ] Signed-off-by: Sasha Levin --- net/mptcp/pm_netlink.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/net/mptcp/pm_netlink.c b/net/mptcp/pm_netlink.c index 8d5406515c304..4d9a5c8f3b2f0 100644 --- a/net/mptcp/pm_netlink.c +++ b/net/mptcp/pm_netlink.c @@ -618,6 +618,10 @@ static void mptcp_pm_create_subflow_or_signal_addr(struct mptcp_sock *msk) } subflow: + /* No need to try establishing subflows to remote id0 if not allowed */ + if (mptcp_pm_add_addr_c_flag_case(msk)) + goto exit; + /* check if should create a new subflow */ while (msk->pm.local_addr_used < local_addr_max && msk->pm.subflows < subflows_max) { @@ -649,6 +653,8 @@ static void mptcp_pm_create_subflow_or_signal_addr(struct mptcp_sock *msk) __mptcp_subflow_connect(sk, &local, &addrs[i]); spin_lock_bh(&msk->pm.lock); } + +exit: mptcp_pm_nl_check_work_pending(msk); } -- 2.51.0