From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 73214364E89; Mon, 28 Sep 2026 21:18:06 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790630288; cv=none; b=senLT2axYMllpqtUehjsDZWjq+/4ZYvUC8QcPfTXkrKmTZTvdnW5iV4056EEp/hsxcdTOGkPVdY5ehIQYpUc4ldLg5CmKzw8nP5Oel6erq7fS6hkgvNnYITVuhuzThAGkeMgQqg+9qcMyMISPk2mjQNwzD/IBSfFSmHZxq6X9xg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790630288; c=relaxed/simple; bh=7M7fJ5FstXWzL5H1GQ2KodG1IQeWAG9XJtykoxuneAQ=; h=Message-ID:Date:MIME-Version:Subject:From:To:Cc:References: In-Reply-To:Content-Type; b=NhkKnaUExG2z77jg3XatGltVxSka0tItv+Uo47V+/l5Em1bF3NLYEIQLw7X1xU5umkYzTXk0nLFFRSjKAr6Wo2y5d0T49wAjnZMAGCeFWvZbD4cEphb1wuVLpxclilxxqy+x/yjU9eMvP4UnMjmvEOOaDKurAXPcilAReLr+Xg0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=dB9H5IKe; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="dB9H5IKe" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3AC891F000FF; Mon, 28 Sep 2026 21:18:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1790630286; bh=TFPWYRQoyz6NWOuEze9ht0jM/GEuJCUXxLhM2GrLzxU=; h=Date:Subject:From:To:Cc:References:In-Reply-To; b=dB9H5IKeAnra4gl9EZU9Ss3vj8CAYtRSkGFQHsZtDA1K0cSG3Mep+RsQViwoNTU/8 AtSgEppgX+Den+KR9JprebA9MVJKryIiZw3CmG9J8iBAoT8KcqHUoJ7agr1ljceRiX eX+/vZGHJUOzzphPFIhYp6TaVsoW7FTgH9vPuOGQyL8PYKvqj6Sqyx0Z9WUve+rS+U EyXPeYO1z4NcfAbuFfrO8HGJUJAyeH865jo9HH37/Vu7yObS5YMyGNWpe9loDcVXqc epBNHVF6RboR3plEO4+q4fu8WJCJQhEClGWJhBAAz7SpTLj2Ihc3hROZCXpVgxaCrf N8362+EWdbmiA== Message-ID: <4278a970-2957-4387-8f20-604ae4ae97e9@kernel.org> Date: Mon, 28 Sep 2026 23:17:59 +0200 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Beta Subject: Re: [PATCH net-next 5/5] selftests: mptcp: convert iptables to nftables for mptcp_join.sh Content-Language: fr From: Matthieu Baerts To: netdev-bot+sashiko@kernel.org, Hangbin Liu Cc: martineau@kernel.org, geliang@kernel.org, davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, horms@kernel.org, netdev@vger.kernel.org, mptcp@lists.linux.dev, linux-kernel@vger.kernel.org, quanyeyang@proton.me References: <20260926-net-next-mptcp-misc-feat-7-4-v1-5-67af4ab37406@kernel.org> <179058242453.3145.1450534124183352369@kernel.org> Autocrypt: addr=matttbe@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 8bit On 28/09/2026 13:24, Matthieu Baerts wrote: > Hello, > > On 28/09/2026 10:00, netdev-bot+sashiko@kernel.org wrote: >> Thank you for your contribution! Sashiko AI review found 2 potential >> issue(s) to consider. >> >> Critical: 0 · High: 0 · Medium: 1 · Low: 1 >> >> If you believe none of the issues are legitimate, please reply to each >> issue of Medium severity or higher and explain why the AI is wrong. > > TL;DR: It looks like there are issues with NFTables, but no new version > needed here for these MPTCP patches. > >> If any of them are legitimate and you plan to respin, please let patchwork >> know by including "pw-bot: cr" as a separate line at the end of your reply >> (one such reply per series is enough). >> >> - [Medium] In endpoint_tests() >> (tools/testing/selftests/net/mptcp/mptcp_join.sh), the new rule `tcp… >> - [Low] The patch removes CONFIG_NFT_COMPAT from >> tools/testing/selftests/net/mptcp/config, "since we don't need it now". >> >> -- >> >> selftests: mptcp: convert iptables to nftables for mptcp_join.sh >> >> This converts the iptables/ip6tables rules in mptcp_join.sh to nftables. >> It keeps the same table and chain names and adds init_nftables() to set >> up the tables only when a test needs them. The cBPF bytecode that matched >> the ADD_ADDR and RM_ADDR suboptions is replaced with "tcp option mptcp >> subtype" matching. In the config fragment, CONFIG_NFT_COMPAT is swapped >> for the nft modules that are now needed. > > (...) > >>> diff --git a/tools/testing/selftests/net/mptcp/mptcp_join.sh b/tools/testing/selftests/net/mptcp/mptcp_join.sh >>> index 18ce7136a2b0e..b16e24418e737 100755 >>> --- a/tools/testing/selftests/net/mptcp/mptcp_join.sh >>> +++ b/tools/testing/selftests/net/mptcp/mptcp_join.sh >> >> [ ... ] >> >>> @@ -4402,12 +4372,10 @@ endpoint_tests() >>> >>> # To make sure RM_ADDR are sent over a different subflow, but >>> # allow the rest to quickly and cleanly close the subflow >>> - local ipt=1 >>> - ip netns exec "${ns2}" ${iptables} -I OUTPUT -s "10.0.1.2" \ >>> - -p tcp -m tcp --tcp-option 30 \ >>> - -m bpf --bytecode \ >>> - "$CBPF_MPTCP_SUBOPTION_RM_ADDR" \ >>> - -j DROP || ipt=0 >>> + local nft=1 >>> + ip netns exec "${ns2}" nft insert rule ip filter OUTPUT \ >>> + ip saddr 10.0.1.2 meta l4proto tcp \ >>> + tcp option mptcp subtype remove-addr drop || nft=0 >> >> [Severity: Medium] >> Can this rule ever match an RM_ADDR packet on an established connection? >> >> nft_exthdr_tcp_eval() stops at the first TCP option whose kind matches >> (30 for MPTCP). The subtype check therefore only ever sees the first >> MPTCP suboption: >> >> net/netfilter/nft_exthdr.c:nft_exthdr_tcp_eval() { >> ... >> for (i = sizeof(*tcph); i < tcphdr_len - 1; i += optl) { >> optl = optlen(opt, i); >> >> if (priv->type != opt[i]) >> continue; >> ... >> return; >> } >> ... >> } > > Indeed, the RM_ADDR will be added in a second MPTCP option. It looks > like Netfilter doesn't handle that case. But that seems to be an issue > on the Netfilter side, rather than with the command that should work. I > will follow up with Netfilter devs. If a fix cannot be added on their > side, I will change the nft command to look at a specific offset. > > Note that the command here is just to check there is no RM_ADDR sent on > the wrong side: it shouldn't catch any packets here anyway. After a discussion with Netfilter devs, it looks like a fix will not be easy to have. Yet, I wonder if it wouldn't be better to apply this patch like that (it doesn't break things), and have an explicit follow-up/fix to document this issue somehow. @Hangbin: do you plan to look at a fix for that? I guess a raw payload looking at the same fields as what the previous cBPF rule was doing would be enough. Don't hesitate to fix the "low" priority comments as well. https://lore.kernel.org/all/20260926-net-next-mptcp-misc-feat-7-4-v1-0-67af4ab37406@kernel.org/T/#u Cheers, Matt -- Sponsored by the NGI0 Core fund.