From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 539DFC433FE for ; Sat, 9 Apr 2022 09:51:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232347AbiDIJyB (ORCPT ); Sat, 9 Apr 2022 05:54:01 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39180 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231248AbiDIJyB (ORCPT ); Sat, 9 Apr 2022 05:54:01 -0400 Received: from Chamillionaire.breakpoint.cc (Chamillionaire.breakpoint.cc [IPv6:2a0a:51c0:0:12e:520::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id EC973E0C9 for ; Sat, 9 Apr 2022 02:51:53 -0700 (PDT) Received: from fw by Chamillionaire.breakpoint.cc with local (Exim 4.92) (envelope-from ) id 1nd7l2-0007O8-51; Sat, 09 Apr 2022 11:51:52 +0200 Date: Sat, 9 Apr 2022 11:51:52 +0200 From: Florian Westphal To: Topi Miettinen Cc: netfilter-devel@vger.kernel.org Subject: Re: [PATCH] doc: Document that kernel may accept unimplemented expressions Message-ID: <20220409095152.GA19371@breakpoint.cc> References: <20220409094402.22567-1-toiwoton@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220409094402.22567-1-toiwoton@gmail.com> User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: netfilter-devel@vger.kernel.org Topi Miettinen wrote: > Kernel silently accepts input chain filters using meta skuid, meta > skgid, meta cgroup or socket cgroupv2 expressions but they don't work > yet. Warn the users of this possibility. > > Signed-off-by: Topi Miettinen > --- > doc/nft.txt | 5 +++++ > 1 file changed, 5 insertions(+) > > diff --git a/doc/nft.txt b/doc/nft.txt > index f7a53ac9..4820b4ae 100644 > --- a/doc/nft.txt > +++ b/doc/nft.txt > @@ -932,6 +932,11 @@ filter output oif wlan0 > ^^^^^^^^^^^^^^^^^^^^^^^ > --------------------------------- > > +Note that the kernel may accept expressions without errors even if it > +doesn't implement the feature. For example, input chain filters using > +*meta skuid*, *meta skgid*, *meta cgroup* or *socket cgroupv2* > +expressions are silently accepted but they don't work yet. Thats not correct. Those expressions load values from skb->sk, i.e. the socket associated with the packet. In input, such socket may exist, either because of tproxy rules, early demux, or bpf programs.