From nobody Sun Dec 14 06:18:16 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 326432701B1 for ; Wed, 23 Apr 2025 09:40:51 +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=1745401253; cv=none; b=ewOx48mYrvndCrLUPs6n4ZnHXguFgd5S9TL6zPwRrsQaNAlqZ8S9rHPqxzNBCD0ppNryJgNGPEsHq4iW4vhkpXankIQdhTSSHrZJ4BdiHsGj8tLzpWgjhDl3Ep7Ck4gui02g9sp7sI7RSPEdF53fJnAd649ck8UhnMtV+sBMgAM= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745401253; c=relaxed/simple; bh=MhAHx5bVmBey5XvXe90ZD+YCTc0dE13hi9qKwowki4Q=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=gcgfJXzHeLUgHvGLNkE7GlgBa6GTUQt//tAr4F8KQge3WJq1heCftWA8E5ZCYLVnOcNKyLloydd1ZOlU3q2zjqFchPCHnJ3qni3WwGJNWs0nouXFGaw8VVtJlCmF0KLRPimoZhC2QGTmboS4Cg2ZjKs/klqeWSme1bSfoi6vHUA= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=GJdZNcDK; 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="GJdZNcDK" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 79F3AC4CEE2; Wed, 23 Apr 2025 09:40:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1745401251; bh=MhAHx5bVmBey5XvXe90ZD+YCTc0dE13hi9qKwowki4Q=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=GJdZNcDKQ1zmnop1OStxOcEXmoMZCb5SPU9BSBNDczDSMhVM0sHmGtANhSYDk89Fh y7Oi2AdRw9go9D8lox9ipF9dokxSNa6ILOdgul0F82b+6+11APWsxZLV+xPyv2rUHd WqnxRfZxeeO4zK89zeH/qlfYwXE+lgRPsfk2VOR4JmznPDaL26EmyId3ZHjnnajtbF hnDe9fvQEKS8xbSLjQST+s7FXyXUB1ebbX6xfhfvRWCqaBFt+anAAoQ4Aklu36+kP/ Ow4+jD1fnNXnVj27UHsfTEtlxJ5tgoLOI7jbg672bpRbwu1gyzB/Ol6Jbzo95jn9yo HWf3bxabFnOVw== From: Geliang Tang To: mptcp@lists.linux.dev Cc: Geliang Tang Subject: [PATCH mptcp-next v2 1/3] tcp: add tcp_sock_set_maxseg Date: Wed, 23 Apr 2025 17:40:40 +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 Add a helper tcp_sock_set_maxseg() to directly set the TCP_MAXSEG sockopt from kernel space. Signed-off-by: Geliang Tang Acked-by: Matthieu Baerts (NGI0) --- include/linux/tcp.h | 1 + net/ipv4/tcp.c | 24 +++++++++++++++--------- 2 files changed, 16 insertions(+), 9 deletions(-) diff --git a/include/linux/tcp.h b/include/linux/tcp.h index 1669d95bb0f9..0041bc0aaee9 100644 --- a/include/linux/tcp.h +++ b/include/linux/tcp.h @@ -623,6 +623,7 @@ 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 4516f93f6cd2..402f4a9b3fd1 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -3725,6 +3725,20 @@ 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; +} +EXPORT_SYMBOL(tcp_sock_set_maxseg); + /* * Socket option code for TCP. */ @@ -3857,15 +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