From nobody Sun Dec 14 05:53:38 2025 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 407A4202C21 for ; Tue, 22 Apr 2025 09:32:00 +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=1745314321; cv=none; b=q34qkY3LXl2/qoriTtgvML2iStJ2meX+Y2PyAvCBl6Ow1fSlIaOBWdla2gb6F+AAR8/JrhleiCq51kSXN8exriItqPfUmJRTzmxf099xCUtdJ1vflGjpYWHmQkKTlOaQ1pVjg/OOWnYqRtzH5nrGSIQgEtK1WwWjqHvzUtVASso= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745314321; c=relaxed/simple; bh=CGsrBcKI6v3kABL0+eExA3y73MnxBRshNjk+HcTKG5o=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=HExKgi1vW41YiiQplipSNqMG8Wx+jKgB2Nr9SibkYHsXyZaCUDzS4zJh3/nfaMKKBfzjGBJP+CL3AsMkT719JSidSls+jxCztz+is3RI970zqhcoQsM3V41r+9gU8A0bFDkk40dMNTTcp/Q+bdY6+RsfkRrJ5ybnW5wJFwkjCMo= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=g3kg67hq; 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="g3kg67hq" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B1E61C4CEEC; Tue, 22 Apr 2025 09:31:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1745314320; bh=CGsrBcKI6v3kABL0+eExA3y73MnxBRshNjk+HcTKG5o=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=g3kg67hqAEFiCAZxMN/xMlSNj42smpsdTuRrrFIk9PhhXrcOKq6imr8qEtZS7Wked 0pKnYe8+7JQ/QmfRAhhkTaGmA62ROlxxXLI130AdGLn1uj0mRG5TJER/P6D/Afdwvw XT9z8H2hfp+4VSdqEqnMHu2D6g1UmpvZcBhAvPTdEqN6L7q5t6T8WwHn8MfJFgTV8u oRnSDFnPfgBGtnnwNdH7h/Wg+2LkoPlshtLk9/m2uOUIUeSiApYtag6e5D1lyv/SW3 SDA1bkmH1rdD37Vu8YWlKhK3USJyIUinC08hpAR2tikDlsleprnerYIRdi49b9N4O5 ikAfZ3S73Ybzg== From: Geliang Tang To: mptcp@lists.linux.dev Cc: Geliang Tang Subject: [PATCH mptcp-next v1 1/2] mptcp: add TCP_MAXSEG sockopt support Date: Tue, 22 Apr 2025 17:30:44 +0800 Message-ID: <73d0d8594eaee83d2902ca23c3972ec5e6d628f4.1745314165.git.tanggeliang@kylinos.cn> X-Mailer: git-send-email 2.43.0 In-Reply-To: References: Precedence: bulk X-Mailing-List: mptcp@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Geliang Tang The TCP_MAXSEG socket option is currently not supported by MPTCP, mainly because it has never been requested before. But there are still valid use-cases, e.g. with HAProxy. This patch adds its support in MPTCP by propagating the value to all subflows. Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/515 Signed-off-by: Geliang Tang --- net/mptcp/sockopt.c | 29 +++++++++++++++++++++++++++++ 1 file changed, 29 insertions(+) diff --git a/net/mptcp/sockopt.c b/net/mptcp/sockopt.c index 3caa0a9d3b38..3014713b037c 100644 --- a/net/mptcp/sockopt.c +++ b/net/mptcp/sockopt.c @@ -798,6 +798,24 @@ static int mptcp_setsockopt_first_sf_only(struct mptcp= _sock *msk, int level, int return ret; } =20 +static int mptcp_setsockopt_sol_tcp_maxseg(struct mptcp_sock *msk, + sockptr_t optval, + unsigned int optlen) +{ + struct mptcp_subflow_context *subflow; + + mptcp_for_each_subflow(msk, subflow) { + struct sock *ssk =3D mptcp_subflow_tcp_sock(subflow); + int ret; + + ret =3D tcp_setsockopt(ssk, SOL_TCP, TCP_MAXSEG, optval, optlen); + if (ret) + return ret; + } + + return 0; +} + static int mptcp_setsockopt_sol_tcp(struct mptcp_sock *msk, int optname, sockptr_t optval, unsigned int optlen) { @@ -819,6 +837,8 @@ static int mptcp_setsockopt_sol_tcp(struct mptcp_sock *= msk, int optname, case TCP_FASTOPEN_NO_COOKIE: return mptcp_setsockopt_first_sf_only(msk, SOL_TCP, optname, optval, optlen); + case TCP_MAXSEG: + return mptcp_setsockopt_sol_tcp_maxseg(msk, optval, optlen); } =20 ret =3D mptcp_get_int_option(msk, optval, optlen, &val); @@ -1368,6 +1388,13 @@ static int mptcp_put_int_option(struct mptcp_sock *m= sk, char __user *optval, return 0; } =20 +static int mptcp_getsockopt_sol_tcp_maxseg(struct mptcp_sock *msk, + char __user *optval, + int __user *optlen) +{ + return tcp_getsockopt(msk->first, SOL_TCP, TCP_MAXSEG, optval, optlen); +} + static int mptcp_getsockopt_sol_tcp(struct mptcp_sock *msk, int optname, char __user *optval, int __user *optlen) { @@ -1407,6 +1434,8 @@ static int mptcp_getsockopt_sol_tcp(struct mptcp_sock= *msk, int optname, return mptcp_put_int_option(msk, optval, optlen, msk->notsent_lowat); case TCP_IS_MPTCP: return mptcp_put_int_option(msk, optval, optlen, 1); + case TCP_MAXSEG: + return mptcp_getsockopt_sol_tcp_maxseg(msk, optval, optlen); } return -EOPNOTSUPP; } --=20 2.43.0