From nobody Sun Dec 14 08:06:54 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 2D0162701B1 for ; Wed, 23 Apr 2025 09:40:53 +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=1745401255; cv=none; b=ZcxB0ChL2s1F2LqFl4/TBtySPEWTL8BxuqekIxPJcG7+lRmrBQh6toIXOSTKfdCcs27wNUbB3Y4bJjgLmQ4+eM8ErHJAHQFN1V1cNFxGijFS9rf22g6fFr/bSgN0EzxVGbY5m8IQr5B8MRSaBp12fNA89QEfyUHxE8tmrs7AW10= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745401255; c=relaxed/simple; bh=itfQbPsn1BntUraeR373sWvbaxL8NsijCSxuKEkhTgE=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Ex3eKoZujAE4oUp6+5eWMmmfOrQCXV79sqtXIEx2hrbZvWEP9HfkFtbgKSx8ds2a8+u/yyk9olMMihFaMHuhdLVnkznQe0oy/5n0ja59YZhRZuKhbaEt1vbXMC4ZHFCowBn4kI1PenBVGrXG3PstgG5c5j3IXJzaebXuvBvQ4Ho= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=e0sEFbIQ; 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="e0sEFbIQ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 52920C4CEEC; Wed, 23 Apr 2025 09:40:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1745401253; bh=itfQbPsn1BntUraeR373sWvbaxL8NsijCSxuKEkhTgE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=e0sEFbIQDFJt0upXQAJuoUx7mx3MuDBEaXTF+s3r0hoOfYF2XRcrOqzbTbH2EOzQL kZsUJGIS7UeWslB8tlEZFkOc+sJ7rcGLAseEB+wQUtgO9olDiswAVW+JWNSeArymx5 b8Itiwb3snVTLzWizt6mtkhTrj+Fn2iuUJ5jKLnbVlEbLrmWlrXzZuU4QbQY7WDRfU 8jgEmmBhI2THp6aPCvquyGWwkFRPDmv0xVMbgq+daSXnQB+wBKmqlOscrhKuC/5NkD zUK8YgnSrvPPihKtzE1v6iX0Uv4tL4aO9pkKcMMqjv7UkBmezzSEApYF8ZaEE2X69q WpZ0L1ZG+fVXA== From: Geliang Tang To: mptcp@lists.linux.dev Cc: Geliang Tang Subject: [PATCH mptcp-next v2 2/3] mptcp: add TCP_MAXSEG sockopt support Date: Wed, 23 Apr 2025 17:40:41 +0800 Message-ID: <8160ae5fd83c0815cee2f5998948199200574bc7.1745401025.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. 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 --- net/mptcp/protocol.h | 1 + net/mptcp/sockopt.c | 24 ++++++++++++++++++++++++ 2 files changed, 25 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 3caa0a9d3b38..a7992cbc5ed9 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; } @@ -1407,6 +1428,8 @@ 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_put_int_option(msk, optval, optlen, msk->maxseg); } return -EOPNOTSUPP; } @@ -1553,6 +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