From nobody Sun Dec 14 06:35:57 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 080A41E32D7 for ; Wed, 30 Apr 2025 05:49:53 +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=1745992194; cv=none; b=nNRuLEaX1RgvjELWqPTmgXy0g4xaCntdceO1wOusqPWTcpoe3KuqXTwLv0RqVxgMdv2ThIKmZnfBi2TCPwK3v8sE7vwqmY8HhvY9UkHx4eREr8y9VffOweJ8kxFoWqw2jG60n+0eUUcXVp+E3L5YwVr9zenOtTbTATEJsQ3g/U8= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745992194; c=relaxed/simple; bh=R89UzM8Nl2S0Dk+t/6mqljP1CoB32z2e10z66oqIp7o=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=AC/ArvHMvZuLQL2girRdEcu3a9CPQRQkjc3D29KbbbvZXENsslaonyYciv55x8bqfDmkCyG1lHJPlJxUYNZwxxpLb5+zhYyqHRRAYsV7vvQaUjyWeHELWLuUqPLoW6I0KIo0Jp6WqAfateZbxgO3AsTiQiWLOUFM6iZfdkD4GmE= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=lwOPK8Qh; 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="lwOPK8Qh" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 003F0C4CEEA; Wed, 30 Apr 2025 05:49:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1745992193; bh=R89UzM8Nl2S0Dk+t/6mqljP1CoB32z2e10z66oqIp7o=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=lwOPK8Qh+aYW+cuhN0mw5ml3VFoJJ3TiPzddrrgmU6nzthaQcPx1s1Jt7RmfsU9mP DJ6diVvfUxy+K1/ejo+Ul2FfUXB0xY0uKu6nqfkKk0zvniqa4T6J5rc3HULJhcG62k V+fe5SmzP9X1wQx47X6dZgsTvu0ygaikw8Z6BM5ZcpKvzHgnFlwQ+QHD8CR3kO0f4Z tZzIAN9PimCjifqxztk0Pp6YQZQpCgL54uqFOj+ZP5l3dxV4RYsj9z4zRrfid3Amit cbD0O1heEQhbqtI6+uAKKG4C7YiOBEAwuMm2fKi4FFxD7/AEY7y4BKHD1wCDa5EamS ua4eNmSH1ykoQ== From: Geliang Tang To: mptcp@lists.linux.dev Cc: Geliang Tang , Matthieu Baerts Subject: [PATCH mptcp-next v3 1/2] tcp: add tcp_sock_set_maxseg Date: Wed, 30 Apr 2025 13:49:44 +0800 Message-ID: <65512e0b126b894d029cad693f8d6b44f70ec311.1745991978.git.geliang@kernel.org> 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 Add a helper tcp_sock_set_maxseg() to directly set the TCP_MAXSEG sockopt from kernel space. This new helper will be used in the following patch. Acked-by: Matthieu Baerts (NGI0) Signed-off-by: Geliang Tang --- include/linux/tcp.h | 1 + net/ipv4/tcp.c | 23 ++++++++++++++--------- 2 files changed, 15 insertions(+), 9 deletions(-) diff --git a/include/linux/tcp.h b/include/linux/tcp.h index a8af71623ba7..41206c3f289f 100644 --- a/include/linux/tcp.h +++ b/include/linux/tcp.h @@ -624,6 +624,7 @@ void tcp_sock_set_nodelay(struct sock *sk); void tcp_sock_set_quickack(struct sock *sk, int val); int tcp_sock_set_syncnt(struct sock *sk, int val); int tcp_sock_set_user_timeout(struct sock *sk, int val); +int tcp_sock_set_maxseg(struct sock *sk, int val); =20 static inline bool dst_tcp_usec_ts(const struct dst_entry *dst) { diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index e1bbb070e734..e1f00faed760 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -3726,6 +3726,19 @@ int tcp_set_window_clamp(struct sock *sk, int val) return 0; } =20 +int tcp_sock_set_maxseg(struct sock *sk, int val) +{ + /* Values greater than interface MTU won't take effect. However + * at the point when this call is done we typically don't yet + * know which interface is going to be used + */ + if (val && (val < TCP_MIN_MSS || val > MAX_TCP_WINDOW)) + return -EINVAL; + + tcp_sk(sk)->rx_opt.user_mss =3D val; + return 0; +} + /* * Socket option code for TCP. */ @@ -3858,15 +3871,7 @@ int do_tcp_setsockopt(struct sock *sk, int level, in= t optname, =20 switch (optname) { case TCP_MAXSEG: - /* Values greater than interface MTU won't take effect. However - * at the point when this call is done we typically don't yet - * know which interface is going to be used - */ - if (val && (val < TCP_MIN_MSS || val > MAX_TCP_WINDOW)) { - err =3D -EINVAL; - break; - } - tp->rx_opt.user_mss =3D val; + tcp_sock_set_maxseg(sk, val); break; =20 case TCP_NODELAY: --=20 2.43.0