From nobody Sun Dec 14 06:45:03 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 C67BB1E32D3 for ; Wed, 30 Apr 2025 05:49:55 +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=1745992195; cv=none; b=Htgt8c1L+sykAXuMQHVCRObn+3rEvGf17/cC/2Ip70HiG+ywRejlWf0fuSlvIlDq8W8dA4bSBesK33HeJyb/3UUo5Mo6PRpBze4r2xilGHOub7/O6Fxkd2YUdc/kUSM2d4tFQS/0Lej4DMKRJEM0JOdJK1jr9gHRTF6xNrsdr0w= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745992195; c=relaxed/simple; bh=3VYPnAy6jQfXdvjrxqQcao6d89NaXnZKASEGyczSm3A=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=T7os6jSpHGl2PnJ8MXN9TNqiMDRw3W6BeTZSz8czj8OnAFkyPyh0QGJa8vFQqrpB64u6gOlc5zvbon+foSCcCQ3gIOpiqTqasggnhyGNMsNJ6CyR3OK/ped1L9KEoVUm9MsAL8pJDJYdKxGBZoTkIDehdxIinoma7W9NZbBoJGI= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=gyibBAEr; 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="gyibBAEr" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 24BC0C4CEEC; Wed, 30 Apr 2025 05:49:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1745992195; bh=3VYPnAy6jQfXdvjrxqQcao6d89NaXnZKASEGyczSm3A=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=gyibBAErQFcbVIIFgj/OuOXME3jaHPABHhralkm9W+q90exdKI0qFZqMIdiKZlnkH 9Jrk581qcyMMuUWxUeLTr5C9wfdo2989rak+0XRrjkz8XpOJmUaY5FDuDJTrzFhZTf bfUBiAKo8+zws2rm4lc6pNyNNQ5EjjQMDUggES0mI0eNa302G0sfUv742Y1H7FeTab Ohi5Dl25zROQEWJp4Q3rLmvnSmWIK9X0cyaOX/EmRXEEX+naD/OA1v/o25mXVysJY1 OZSoh8YsrplqiOZu+LUvFz9ziugIdgGkkN0CVZsegNF9LTFEHUNUtc+bjH9Pc2+8pJ 9CFeSgvPv+wLw== From: Geliang Tang To: mptcp@lists.linux.dev Cc: Geliang Tang Subject: [PATCH mptcp-next v3 2/2] mptcp: add TCP_MAXSEG sockopt support Date: Wed, 30 Apr 2025 13:49:45 +0800 Message-ID: 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. Similar to mptcp_setsockopt_first_sf_only(), a generic helper mptcp_setsockopt_all_subflows() is added to set sockopt for each subflows of the mptcp socket. Add a new member for struct mptcp_sock to store the TCP_MAXSEG value, and return this value in getsockopt. Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/515 Signed-off-by: Geliang Tang Reviewed-by: Matthieu Baerts (NGI0) --- net/mptcp/protocol.h | 1 + net/mptcp/sockopt.c | 25 +++++++++++++++++++++++++ 2 files changed, 26 insertions(+) diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h index 64aa091cb685..91aaed17fe56 100644 --- a/net/mptcp/protocol.h +++ b/net/mptcp/protocol.h @@ -327,6 +327,7 @@ struct mptcp_sock { int keepalive_cnt; int keepalive_idle; int keepalive_intvl; + int maxseg; struct work_struct work; struct sk_buff *ooo_last_skb; struct rb_root out_of_order_queue; diff --git a/net/mptcp/sockopt.c b/net/mptcp/sockopt.c index afa54fba51e2..5a002dd05cc9 100644 --- a/net/mptcp/sockopt.c +++ b/net/mptcp/sockopt.c @@ -798,6 +798,22 @@ static int mptcp_setsockopt_first_sf_only(struct mptcp= _sock *msk, int level, int return ret; } =20 +static int mptcp_setsockopt_all_subflows(struct mptcp_sock *msk, int level= , int optname, + 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 =3D 0; + + ret =3D tcp_setsockopt(ssk, level, optname, 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) { @@ -859,6 +875,11 @@ static int mptcp_setsockopt_sol_tcp(struct mptcp_sock = *msk, int optname, &msk->keepalive_cnt, val); break; + case TCP_MAXSEG: + msk->maxseg =3D val; + ret =3D mptcp_setsockopt_all_subflows(msk, SOL_TCP, optname, + optval, optlen); + break; default: ret =3D -ENOPROTOOPT; } @@ -1406,6 +1427,9 @@ 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_first_sf_only(msk, SOL_TCP, optname, + optval, optlen); } return -EOPNOTSUPP; } @@ -1552,6 +1576,7 @@ static void sync_socket_options(struct mptcp_sock *ms= k, struct sock *ssk) tcp_sock_set_keepidle_locked(ssk, msk->keepalive_idle); tcp_sock_set_keepintvl(ssk, msk->keepalive_intvl); tcp_sock_set_keepcnt(ssk, msk->keepalive_cnt); + tcp_sock_set_maxseg(ssk, msk->maxseg); =20 inet_assign_bit(TRANSPARENT, ssk, inet_test_bit(TRANSPARENT, sk)); inet_assign_bit(FREEBIND, ssk, inet_test_bit(FREEBIND, sk)); --=20 2.43.0