From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from desiato.infradead.org (desiato.infradead.org [90.155.92.199]) (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 370CC38552F; Wed, 1 Apr 2026 07:45:39 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=90.155.92.199 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775029545; cv=none; b=DBF5fLoR5w3vQQqHSeQ6809h2L1zGT8ZcC3U0Xi45v0QJp705Chq53nTQ0a14THwgK/1vuYIOrYiAbdqHpmoGJKAqfFF8fFnNVIGEp8cmTo2H5VXAXG5wfMIHsnIlt4SVyxTkdYHSYIfXfvAir1SWmVoOydmHy1AHqy9j0gy8aM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775029545; c=relaxed/simple; bh=qN7W5IBVBu/OQTCESu4Ceo7yTOnBD6XUujV3W2X5nu8=; h=From:To:Subject:Date:Message-ID:MIME-Version; b=Fo8BJRKys1ArCG1GrCKGbO7v+uajmYkwBheiMH04hY6F2ybJtbQ4xxTY5s3uq+2Tkx+duq18CS0EwERyym2YuPI07Moj8Rj/APKNcvhC3NbmTJCqr/ZZ4eMH/xOVIG91ZlIxDOR62e2RJVFHbtJIFTd7w0Q+YTBawfB9fscvhMo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=infradead.org; spf=none smtp.mailfrom=desiato.srs.infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=qppyHh4y; arc=none smtp.client-ip=90.155.92.199 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=desiato.srs.infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="qppyHh4y" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=desiato.20200630; h=Sender:Content-Transfer-Encoding: MIME-Version:Message-ID:Date:Subject:To:From:Reply-To:Cc:Content-Type: Content-ID:Content-Description:In-Reply-To:References; bh=ocYqYAcgR1+/f5z2PeObgww9KvTkVcu5upOhy12M96c=; b=qppyHh4yVyPfuZinNmzNuvUo98 ZzIQLIAkGtEusEFCWJLH056dBP0ZGgDld2dbOncKsxuY3CdOjHfDNBojsMgurWLZKRZ2VEb3DZ6lI RfsN1GcZUdsyEr5B7f5wp3K35mkdWnmyVDGQZSmA2Dl6j2mZNYm0KMTuEEl/7vMAvNs4ePewrI7FM 2O0TjqZhbd94Bc4ck74/suWRXQ1kS8kGuAZt/IXK5LxpTVyqsK5xpycHKG97uEHKkkxJzhThrDmJM IuvFXMEMqWQbh3URIbtzq1ou7YPYh8Z6QUyTRAgNmBChGcFHdjPbAAcsH5RXTZWoNL3MngVsfUPBL re9IFLlA==; Received: from [2001:8b0:10b:1::425] (helo=i7.infradead.org) by desiato.infradead.org with esmtpsa (Exim 4.98.2 #2 (Red Hat Linux)) id 1w7qGN-0000000HLQO-0An7; Wed, 01 Apr 2026 07:45:19 +0000 Received: from dwoodhou by i7.infradead.org with local (Exim 4.98.2 #2 (Red Hat Linux)) id 1w7qGM-00000007xe2-1Dj0; Wed, 01 Apr 2026 08:45:18 +0100 From: David Woodhouse To: Saeed Mahameed , Leon Romanovsky , Tariq Toukan , Mark Bloch , Andrew Lunn , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Simon Horman , Nikolay Aleksandrov , Ido Schimmel , Martin KaFai Lau , Daniel Borkmann , John Fastabend , Stanislav Fomichev , Alexei Starovoitov , Andrii Nakryiko , Eduard Zingerman , Song Liu , Yonghong Song , KP Singh , Hao Luo , Jiri Olsa , Kuniyuki Iwashima , Willem de Bruijn , David Ahern , Neal Cardwell , Johannes Berg , Pablo Neira Ayuso , Florian Westphal , Phil Sutter , Guillaume Nault , David Woodhouse , Kees Cook , Alexei Lazar , Gal Pressman , Paul Moore , netdev@vger.kernel.org, linux-rdma@vger.kernel.org, linux-kernel@vger.kernel.org, oss-drivers@corigine.com, bridge@lists.linux.dev, bpf@vger.kernel.org, linux-wireless@vger.kernel.org, netfilter-devel@vger.kernel.org, coreteam@netfilter.org, torvalds@linux-foundation.org, jon.maddog.hall@gmail.com Subject: [PATCH 0/6] Deprecate Legacy IP Date: Wed, 1 Apr 2026 08:44:14 +0100 Message-ID: <20260401074509.1897527-1-dwmw2@infradead.org> X-Mailer: git-send-email 2.51.0 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: David Woodhouse X-SRS-Rewrite: SMTP reverse-path rewritten from by desiato.infradead.org. See http://www.infradead.org/rpr.html RFC1883, the IPv6 standard, was published in the final decade of the 1900s. That's closer in time to the Apollo 11 moon landing than it was to today. Even our esteemed Maddog has worked with computers for longer in the IPv6 era, than he ever did before it. Yet Linux still can't even be *built* with only IPv6 support and without support for Legacy IP. This long overdue patch series fixes that, and immediately marks Legacy IP for deprecation. It also cleans up a few tautological "INET && IPV6" and "INET || IPV6" checks, since IPV6 (and now LEGACY_IP) cannot be selected without the overall CONFIG_INET option. For now, we only add a warning when a process *listens* on a Legacy IP socket (since you can listen on IPv6 and still accept connections which have come through a timewarp from the 20th century. Adding warnings for making outbound connections or *accepting* on Legacy IP can come later. 'I would be happy if "Legacy IP" ceased to be the "industry standard" and IPv6 be the default, even if I had to beat IPv6 into the head of every single network administrator's head with a shovel.' said Jon 'maddog' Hall, ancient supporter of Free and Open Source Software. David Woodhouse (6): net: Simplify tautological CONFIG_INET/CONFIG_IPV6 guards net: Add CONFIG_LEGACY_IP option net: Guard Legacy IP entry points with CONFIG_LEGACY_IP net: Make IPv4-only Kconfig options depend on LEGACY_IP net: Change CONFIG_INET to CONFIG_LEGACY_IP for IPv4-only code net: Warn when processes listen on AF_INET sockets .../net/ethernet/mellanox/mlx5/core/en/tc_tun.c | 6 ++-- .../net/ethernet/mellanox/mlx5/core/en/tc_tun.h | 2 +- .../ethernet/mellanox/mlx5/core/en/tc_tun_encap.c | 2 +- .../ethernet/netronome/nfp/flower/tunnel_conf.c | 2 +- include/linux/indirect_call_wrapper.h | 4 ++- net/bridge/br_arp_nd_proxy.c | 2 +- net/bridge/br_private.h | 8 +++++ net/core/filter.c | 12 +++---- net/core/secure_seq.c | 2 +- net/core/sock.c | 2 +- net/ipv4/Kconfig | 37 ++++++++++++++++++++++ net/ipv4/af_inet.c | 23 +++++++++++--- net/ipv4/devinet.c | 2 ++ net/ipv4/route.c | 1 - net/ipv4/tcp_ipv4.c | 30 ++++++++++-------- net/mac80211/main.c | 10 +++--- net/netfilter/nfnetlink_queue.c | 2 +- 17 files changed, 105 insertions(+), 42 deletions(-)