From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail.netfilter.org (mail.netfilter.org [217.70.190.124]) (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 9F09B2D600 for ; Tue, 8 Apr 2025 16:37:44 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.70.190.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744130267; cv=none; b=mKUWCx8lQ1i1BM5oAD4xbXTHW2t8ml4pGZX9To0JaHTgpSY7DxlCbEJJeihDEhk4ctEHJ/1jPbp2L/KUeO9qSEH7feugeE4sA/p2XPd/SCxnukIktB/QsRqJd2/1L+sFNwahXQSJlOMP3LuoYkbhTe229WzJ+M9KO8gRkmnYksI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744130267; c=relaxed/simple; bh=oubJ8IQkh+iy6BOT4io5LhcTE8knv84F3KLX4HHzPOA=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=ujjIc3QT06DtVa21RNCvGMk0I60+gfaoSLjNObCO12VAQAGVs9JEg7kourc8Vjbh7LVJgPtGqACD6rk3JGm7GDRE73A/dCnIzVneBBqANng1C0UzAC5SUhGNSmcpucs2206faMM4GHMplNpF539XEJyJPDN5TNFG1FmtMlAwZy0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=netfilter.org; spf=pass smtp.mailfrom=netfilter.org; dkim=pass (2048-bit key) header.d=netfilter.org header.i=@netfilter.org header.b=a0Gr3wTr; dkim=pass (2048-bit key) header.d=netfilter.org header.i=@netfilter.org header.b=GVwFZI2F; arc=none smtp.client-ip=217.70.190.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=netfilter.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=netfilter.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=netfilter.org header.i=@netfilter.org header.b="a0Gr3wTr"; dkim=pass (2048-bit key) header.d=netfilter.org header.i=@netfilter.org header.b="GVwFZI2F" Received: by mail.netfilter.org (Postfix, from userid 109) id E02D86055C; Tue, 8 Apr 2025 18:37:42 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=netfilter.org; s=2025; t=1744130262; bh=S0lJjgIsR2Nj+QQEAG6VqpYG9UU+9VDQNZtx/t9shsc=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=a0Gr3wTrcHQ6JMC0/5eUCTj0DGyb266YEYX5Ty4pZrOWyQLdqyo4w2YMDryXEgdyo MhrCkEgeZYMEH4DA9G80jPCUMyv8VPRtLto0tciWYcsDzmGOg8Rk0FJ27o8g5y0pjW arQzPYtcvBYpv+6UzL7qjHPI9tBjJ291L0R0tN+3sTcJM5J+R7I44ImHKTpjzMcfUa 8jxARk449cfBFcR5/zU0lT9Z0UZSiLEjMRGhM0om5gYfxDqrCfhABetUV6GPSeA4EQ Fc3U4huXDxOdc69N7HvTGEV1riU6OZry/MU55GoNwXm56c5zJuEBkBHzejxDZ1O63W y8acSm5CKmqBg== X-Spam-Level: Received: from netfilter.org (mail-agni [217.70.190.124]) by mail.netfilter.org (Postfix) with ESMTPSA id CDD1D603B2; Tue, 8 Apr 2025 18:37:39 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=netfilter.org; s=2025; t=1744130260; bh=S0lJjgIsR2Nj+QQEAG6VqpYG9UU+9VDQNZtx/t9shsc=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=GVwFZI2F5isOuELBL0iInJijdwXRoy2PAs3onNlgrfAUFZOFtaT9Oaobz1qdviJzy 70mW+/TnxRa5c3nMHmRR8jlpt7XO4LCrZLRorXGUFS0URjZnIq4+QLeUxJB/3juabR o29W+6sxdReOL+czzq/dVrYLLFtM5cqNCSb5wRqD8TdH4lGJ2a1SLX8gS8qc0zAm1j c/JJ3rNp6rHhUr5KNPzK2gmtHLnAtfHxWzop+6Mb/Zz8x32QBeqwabH691Uv3A6iJA SjOftxY7WMqAdEgesncpibsTz2AhzdJwLW1n7y0S8SFQ8ichQhJ3GOWQt4hpf/xom9 JiRxwRcTcDJPQ== Date: Tue, 8 Apr 2025 18:37:36 +0200 From: Pablo Neira Ayuso To: Kuniyuki Iwashima Cc: "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Simon Horman , David Ahern , Neal Cardwell , Willem de Bruijn , Jozsef Kadlecsik , Paul Moore , James Morris , "Serge E. Hallyn" , Kuniyuki Iwashima , netdev@vger.kernel.org Subject: Re: [PATCH v1 net-next 2/4] net: Retire DCCP. Message-ID: References: <20250407231823.95927-1-kuniyu@amazon.com> <20250407231823.95927-3-kuniyu@amazon.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20250407231823.95927-3-kuniyu@amazon.com> Hi Kuniyuki, On Mon, Apr 07, 2025 at 04:17:49PM -0700, Kuniyuki Iwashima wrote: > DCCP was orphaned in 2021 by commit 054c4610bd05 ("MAINTAINERS: dccp: > move Gerrit Renker to CREDITS"), which noted that the last maintainer > had been inactive for five years. > > In recent years, it has become a playground for syzbot, and most changes > to DCCP have been odd bug fixes triggered by syzbot. Apart from that, > the only changes have been driven by treewide or networking API updates > or adjustments related to TCP. > > Thus, in 2023, we announced we would remove DCCP in 2025 via commit > b144fcaf46d4 ("dccp: Print deprecation notice."). > > Since then, only one individual has contacted the netdev mailing list. [0] > > There is ongoing research for Multipath DCCP. The repository is hosted > on GitHub [1], and development is not taking place through the upstream > community. While the repository is published under the GPLv2 license, > the scheduling part remains proprietary, with a LICENSE file [2] stating: > > "This is not Open Source software." > > The researcher mentioned a plan to address the licensing issue, upstream > the patches, and step up as a maintainer, but there has been no further > communication since then. > > Maintaining DCCP for a decade without any real users has become a burden. > > Therefore, it's time to remove it. > > Removing DCCP will also provide significant benefits to TCP. It allows > us to freely reorganize the layout of struct inet_connection_sock, which > is currently shared with DCCP, and optimize it to reduce the number of > cachelines accessed in the TCP fast path. Netfilter parses skbuffs, in that sense, it is a middlebox. Main concern on my side is that it could break rulesets, even for people that don't really see dccp traffic ever, ruleset could stop loading. I would keep the netfilter bits aside by now, based on your netfilter updates, we can internally discuss how to phase out dccp support to get aligned with netdev maintainers, as it seems there is a wish to reduce debt in this front. Having said, this Netfilter does not rely on any of this socket structures, I think it should not be an impediment for your tree spring cleanup (IIRC we have no hard dependencies on CONFIG_DCCP). > Note that we leave uAPI headers alone for userspace programs.