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 1A442221D9C; Mon, 9 Dec 2024 11:31:22 +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=1733743882; cv=none; b=clZXvw4HlUxR81I0iHct48hDg4GEWSzik3jgEOBch1FSwZNAn1Ww9c/A1fNfVAMohYlDuhvZ0JB0KYgyNNIDzHFHL4/3CZhdhqCiUMkokoPAOmUpJX0PcXX4AjC9jZHUPrvqxh1IQWR7flY/FcayDTrV+JeUKBPYW+Fu1cn5sq4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733743882; c=relaxed/simple; bh=CA75l2omv+hK19oiqlXUTMHS50WFKnElsFJ9xaWE/dA=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=tFBCkFkxNyJbNjaNTdjJhgyfT6pTwx1kAdhWldSjouTApB3JQHGT2gZ6k27OS/a/x8tIU6sXNkFOqlGjQZgbWe33DPGggInGB9yDN/N2bboq6hCNF3X5ZLTy/SuPCo6IW42yAaw9JsuWLWq4W9XlyZJ2bB8LEtlFd3LC/Eo6TT4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Il5HO0Ht; 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="Il5HO0Ht" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 959E1C4CED1; Mon, 9 Dec 2024 11:31:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1733743881; bh=CA75l2omv+hK19oiqlXUTMHS50WFKnElsFJ9xaWE/dA=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=Il5HO0Ht79wZ5JbJj/es6EjYbi5nxsS/1Xm0SR3Fxc6P2EWXNi6hNhTAqi/w6EsgY TNOjJZ3B9dhFmpzx3hzRgRjJ+yLohCXsVOcuVEJr5fFn4bHXrI/V3AYdcYSk4MGeRK kWfP53FRVZ6OGlUALxdQwQ9gxym/aDoOlCu2vcwElnba/BM1TutggSrM2EzO7WP2Cz PqydGlGL5Az3K+HuHGISyGBxSmNvvNJkTwQmQfVoVxowUlpFYbg0oKzZHz9LfsKbyH MdQowUSuyUio6l8PVbymyVwAxqChy9IadF3CxOfCMhefDWuBOoWpHhWlLWzE22EONz 2ySMyxe9HH/2Q== Message-ID: Date: Mon, 9 Dec 2024 12:31:15 +0100 Precedence: bulk X-Mailing-List: linux-kselftest@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Beta Subject: Re: [PATCH net-next v12 11/22] ovpn: implement TCP transport Content-Language: en-GB To: Antonio Quartulli Cc: Simon Horman , netdev@vger.kernel.org, Paolo Abeni , Eric Dumazet , Jakub Kicinski , Donald Hunter , Shuah Khan , sd@queasysnail.net, ryazanov.s.a@gmail.com, Andrew Lunn , linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org References: <20241202-b4-ovpn-v12-0-239ff733bf97@openvpn.net> <20241202-b4-ovpn-v12-11-239ff733bf97@openvpn.net> <784fddc4-336c-4674-8277-c7cebea6b94f@redhat.com> <2a1b614c-c52d-44c7-8cb8-c68a8864508d@openvpn.net> <8714deae-c1f7-42ff-9e76-fabd9ca5188b@openvpn.net> <17e7d4c6-4912-4d5e-8723-45a06a1ad529@openvpn.net> <813d75bf-1d7f-472b-967f-27ab8f9d4759@kernel.org> 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: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit On 09/12/2024 11:58, Antonio Quartulli wrote: > On 09/12/2024 11:46, Matthieu Baerts wrote: >> Hi Antonio, >> >> Thank you for working on this, and sharing your work here! >> >> On 05/12/2024 00:09, Antonio Quartulli wrote: >>> On 04/12/2024 23:52, Antonio Quartulli wrote: >>>> Paolo, >>>> >>>> On 04/12/2024 12:15, Antonio Quartulli wrote: >>>> [...] >>>>>>> +        mutex_lock(&tcp6_prot_mutex); >>>>>>> +        if (!ovpn_tcp6_prot.recvmsg) >>>>>>> +            ovpn_tcp_build_protos(&ovpn_tcp6_prot, &ovpn_tcp6_ops, >>>>>>> +                          sock->sk->sk_prot, >>>>>>> +                          sock->sk->sk_socket->ops); >>>>>>> +        mutex_unlock(&tcp6_prot_mutex); >>>>>> >>>>>> This looks like an hack to avoid a build dependency on IPV6, I think >>>>>> the >>>>>> explicit >>>>> >>>>> I happily copied this approach from espintcp.c:espintcp_init_sk() :-D >>>>> >>>>>> >>>>>> #if IS_ENABLED(CONFIG_IPV6) >>>>>> >>>>>> at init time should be preferable >>>> >>>> To get this done at init time I need inet6_stream_ops to be >>>> accessible, but it seems there is no EXPORT_SYMBOL() for this object. >>>> >>>> However, I see that mptcp/protocol.c is happily accessing it. >>>> Any clue how this is possible? >>> >>> I answer myself: mptcp is not tristate and it can only be compiled as >>> built-in. >> >> Indeed, that's why. >> >> Talking about MPTCP, by chance, do you plan to support it later on? :) > > Hi Matthieu, > > It is not on our current roadmap (TCP doesn't get much love in the VPN > world), but I agree it could be an interesting option to explore! I understand, it makes sense not to recommend using TCP for the transport layer for tunnelling solutions. > I have to admit that I haven't played much with MPTCP myself yet, but I > am more than happy to talk about potential advantages for the ovpn use > case. Some people told me they were interested in using OpenVPN with MPTCP to use multiple (low-capacity) network links at the same time. I think intercepting and proxying TCP traffic would always be the best in terms of performances, but using OpenVPN with MPTCP seems to be enough for some, especially when they want to "improve" some type of UDP traffic that cannot be intercepted: QUIC, VPN, etc. I don't have numbers to share, but I can understand this feature can help in some cases. (This reminds me this: https://github.com/OpenVPN/ovpn-dco/issues/60) (and this: https://github.com/arinc9/openvpn/pull/1) Cheers, Matt -- Sponsored by the NGI0 Core fund.