From mboxrd@z Thu Jan 1 00:00:00 1970 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 C4BDE1EFF8E for ; Tue, 22 Apr 2025 11:18:38 +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=1745320718; cv=none; b=lUD8cmi16DHCjom37Vgn3MgiR5H6CreOV7roP/mSGaZsAK+a7Lgm/3W9ZnRWkLKItggDcEC8qArkUustzdLY/Vgdm8EfrbscZST0w4lZ3myLISzZx9kXMeUrIYef5w5erUJvHl173IXeV3JreoOP3E0FzddUCT/WbhHl4iZZfMw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745320718; c=relaxed/simple; bh=9v2GwHVK+pzEOrlq+tFp/dt9nz6ES1vE87BVYXTlBzM=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=jOrz2GuseuBw21E1PPZDCgFGwrcZI0p2j2wjFvsY8p5mDg9Z4GGbon/LV8ec11Tgs3Bs1wqktED/7FMrFu3CkS3lAaC0e12WIpKyABk5StOqJUOvfwgPjYcQkawQXZAxZGddEF14rAXrsMkWpdq/GII7UHDsrWxLVu/10XYG3Y0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=bQlF6+rR; 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="bQlF6+rR" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 73213C4CEF0; Tue, 22 Apr 2025 11:18:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1745320718; bh=9v2GwHVK+pzEOrlq+tFp/dt9nz6ES1vE87BVYXTlBzM=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=bQlF6+rRNghFDB22xufqVPn7MVFttSDJqFvWXaS9aOJHMScBexee+EcJ6RhKwF/b5 wCMl5xzmq8xYDkJNxFbVfuPZBpP71sL+yrwSvH34pj8y/LikojFoT/8Xd4M9ySR0Kn jdGpKXcMQi80Yt3/meHuhqBmuCsqATSIAaezD4G/HSXlxjUCFR9UGY1R0FFeCgS3pw 4+5GCg4wlyb+vGYEcDkvtzVXkXx+H2Lja1hNEmpTVJ9ir2oSp57dX/U0QZPHNYxX9S 2RbTfqm944C3KM48uxeqFEAanigiLx8w0VemdNHyy0RtPVX2g30WhX11iv5TuvfVJb qKp2TCp2eKZ4g== Message-ID: <4f396f53-aed8-4d59-a9b7-56827e1f0139@kernel.org> Date: Tue, 22 Apr 2025 13:18:34 +0200 Precedence: bulk X-Mailing-List: mptcp@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Beta Subject: Re: [PATCH mptcp-next v1 1/2] mptcp: add TCP_MAXSEG sockopt support Content-Language: en-GB, fr-BE To: Geliang Tang , mptcp@lists.linux.dev Cc: Geliang Tang References: <73d0d8594eaee83d2902ca23c3972ec5e6d628f4.1745314165.git.tanggeliang@kylinos.cn> From: Matthieu Baerts Autocrypt: addr=matttbe@kernel.org; keydata= xsFNBFXj+ekBEADxVr99p2guPcqHFeI/JcFxls6KibzyZD5TQTyfuYlzEp7C7A9swoK5iCvf YBNdx5Xl74NLSgx6y/1NiMQGuKeu+2BmtnkiGxBNanfXcnl4L4Lzz+iXBvvbtCbynnnqDDqU c7SPFMpMesgpcu1xFt0F6bcxE+0ojRtSCZ5HDElKlHJNYtD1uwY4UYVGWUGCF/+cY1YLmtfb WdNb/SFo+Mp0HItfBC12qtDIXYvbfNUGVnA5jXeWMEyYhSNktLnpDL2gBUCsdbkov5VjiOX7 CRTkX0UgNWRjyFZwThaZADEvAOo12M5uSBk7h07yJ97gqvBtcx45IsJwfUJE4hy8qZqsA62A nTRflBvp647IXAiCcwWsEgE5AXKwA3aL6dcpVR17JXJ6nwHHnslVi8WesiqzUI9sbO/hXeXw TDSB+YhErbNOxvHqCzZEnGAAFf6ges26fRVyuU119AzO40sjdLV0l6LE7GshddyazWZf0iac nEhX9NKxGnuhMu5SXmo2poIQttJuYAvTVUNwQVEx/0yY5xmiuyqvXa+XT7NKJkOZSiAPlNt6 VffjgOP62S7M9wDShUghN3F7CPOrrRsOHWO/l6I/qJdUMW+MHSFYPfYiFXoLUZyPvNVCYSgs 3oQaFhHapq1f345XBtfG3fOYp1K2wTXd4ThFraTLl8PHxCn4ywARAQABzSRNYXR0aGlldSBC YWVydHMgPG1hdHR0YmVAa2VybmVsLm9yZz7CwZEEEwEIADsCGwMFCwkIBwIGFQoJCAsCBBYC AwECHgECF4AWIQToy4X3aHcFem4n93r2t4JPQmmgcwUCZUDpDAIZAQAKCRD2t4JPQmmgcz33 EACjROM3nj9FGclR5AlyPUbAq/txEX7E0EFQCDtdLPrjBcLAoaYJIQUV8IDCcPjZMJy2ADp7 /zSwYba2rE2C9vRgjXZJNt21mySvKnnkPbNQGkNRl3TZAinO1Ddq3fp2c/GmYaW1NWFSfOmw MvB5CJaN0UK5l0/drnaA6Hxsu62V5UnpvxWgexqDuo0wfpEeP1PEqMNzyiVPvJ8bJxgM8qoC cpXLp1Rq/jq7pbUycY8GeYw2j+FVZJHlhL0w0Zm9CFHThHxRAm1tsIPc+oTorx7haXP+nN0J iqBXVAxLK2KxrHtMygim50xk2QpUotWYfZpRRv8dMygEPIB3f1Vi5JMwP4M47NZNdpqVkHrm jvcNuLfDgf/vqUvuXs2eA2/BkIHcOuAAbsvreX1WX1rTHmx5ud3OhsWQQRVL2rt+0p1DpROI 3Ob8F78W5rKr4HYvjX2Inpy3WahAm7FzUY184OyfPO/2zadKCqg8n01mWA9PXxs84bFEV2mP VzC5j6K8U3RNA6cb9bpE5bzXut6T2gxj6j+7TsgMQFhbyH/tZgpDjWvAiPZHb3sV29t8XaOF BwzqiI2AEkiWMySiHwCCMsIH9WUH7r7vpwROko89Tk+InpEbiphPjd7qAkyJ+tNIEWd1+MlX ZPtOaFLVHhLQ3PLFLkrU3+Yi3tXqpvLE3gO3LM7BTQRV4/npARAA5+u/Sx1n9anIqcgHpA7l 5SUCP1e/qF7n5DK8LiM10gYglgY0XHOBi0S7vHppH8hrtpizx+7t5DBdPJgVtR6SilyK0/mp 9nWHDhc9rwU3KmHYgFFsnX58eEmZxz2qsIY8juFor5r7kpcM5dRR9aB+HjlOOJJgyDxcJTwM 1ey4L/79P72wuXRhMibN14SX6TZzf+/XIOrM6TsULVJEIv1+NdczQbs6pBTpEK/G2apME7vf mjTsZU26Ezn+LDMX16lHTmIJi7Hlh7eifCGGM+g/AlDV6aWKFS+sBbwy+YoS0Zc3Yz8zrdbi Kzn3kbKd+99//mysSVsHaekQYyVvO0KD2KPKBs1S/ImrBb6XecqxGy/y/3HWHdngGEY2v2IP Qox7mAPznyKyXEfG+0rrVseZSEssKmY01IsgwwbmN9ZcqUKYNhjv67WMX7tNwiVbSrGLZoqf Xlgw4aAdnIMQyTW8nE6hH/Iwqay4S2str4HZtWwyWLitk7N+e+vxuK5qto4AxtB7VdimvKUs x6kQO5F3YWcC3vCXCgPwyV8133+fIR2L81R1L1q3swaEuh95vWj6iskxeNWSTyFAVKYYVskG V+OTtB71P1XCnb6AJCW9cKpC25+zxQqD2Zy0dK3u2RuKErajKBa/YWzuSaKAOkneFxG3LJIv Hl7iqPF+JDCjB5sAEQEAAcLBXwQYAQIACQUCVeP56QIbDAAKCRD2t4JPQmmgc5VnD/9YgbCr HR1FbMbm7td54UrYvZV/i7m3dIQNXK2e+Cbv5PXf19ce3XluaE+wA8D+vnIW5mbAAiojt3Mb 6p0WJS3QzbObzHNgAp3zy/L4lXwc6WW5vnpWAzqXFHP8D9PTpqvBALbXqL06smP47JqbyQxj Xf7D2rrPeIqbYmVY9da1KzMOVf3gReazYa89zZSdVkMojfWsbq05zwYU+SCWS3NiyF6QghbW voxbFwX1i/0xRwJiX9NNbRj1huVKQuS4W7rbWA87TrVQPXUAdkyd7FRYICNW+0gddysIwPoa KrLfx3Ba6Rpx0JznbrVOtXlihjl4KV8mtOPjYDY9u+8x412xXnlGl6AC4HLu2F3ECkamY4G6 UxejX+E6vW6Xe4n7H+rEX5UFgPRdYkS1TA/X3nMen9bouxNsvIJv7C6adZmMHqu/2azX7S7I vrxxySzOw9GxjoVTuzWMKWpDGP8n71IFeOot8JuPZtJ8omz+DZel+WCNZMVdVNLPOd5frqOv mpz0VhFAlNTjU1Vy0CnuxX3AM51J8dpdNyG0S8rADh6C8AKCDOfUstpq28/6oTaQv7QZdge0 JY6dglzGKnCi/zsmp2+1w559frz4+IC7j/igvJGX4KDDKUs0mlld8J2u2sBXv7CGxdzQoHaz lzVbFe7fduHbABmYz9cefQpO7wDE/Q== Organization: NGI0 Core In-Reply-To: <73d0d8594eaee83d2902ca23c3972ec5e6d628f4.1745314165.git.tanggeliang@kylinos.cn> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Hi Geliang, On 22/04/2025 11:30, Geliang Tang wrote: > 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. Thank you for looking at that. > 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; > } > > +static int mptcp_setsockopt_sol_tcp_maxseg(struct mptcp_sock *msk, > + sockptr_t optval, > + unsigned int optlen) Might be good to have a generic helper, similar to mptcp_setsockopt_first_sf_only(), no? mptcp_setsockopt_all_subflows() > +{ > + struct mptcp_subflow_context *subflow; > + > + mptcp_for_each_subflow(msk, subflow) { If there is no subflows (listening sockets?), you might need to call mptcp_setsockopt_first_sf_only(), no? > + struct sock *ssk = mptcp_subflow_tcp_sock(subflow); > + int ret; > + > + ret = tcp_setsockopt(ssk, SOL_TCP, TCP_MAXSEG, optval, optlen); No need to lock around this call? > + 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); > } > > ret = mptcp_get_int_option(msk, optval, optlen, &val); > @@ -1368,6 +1388,13 @@ static int mptcp_put_int_option(struct mptcp_sock *msk, char __user *optval, > return 0; > } > > +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); Same here: no need to lock? Also, msk->first can be NULL for listening sockets, no? Anyway, I think it is best not to change the way the socket options are handled today: the socket option is propagated to existing and future subflows. Look how "msk->keepalive_intvl" is handled in sockopt.c for example. - setsockopt: store the value (in case of success) in the msk. - getsockopt: return this value (mptcp_put_int_option()) WDYT? > +} > + > 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; > } Cheers, Matt -- Sponsored by the NGI0 Core fund.