From mboxrd@z Thu Jan 1 00:00:00 1970 From: Patrick McHardy Subject: Re: [PATCH 5/6] netfilter: allow NFQUEUE bypass if no listener is available Date: Tue, 18 Jan 2011 16:09:29 +0100 Message-ID: <4D35AD29.2060400@trash.net> References: <1295183947-12786-1-git-send-email-fw@strlen.de> <1295183947-12786-6-git-send-email-fw@strlen.de> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 Content-Transfer-Encoding: 7bit Cc: netfilter-devel@vger.kernel.org, Florian Westphal To: Florian Westphal Return-path: Received: from stinky.trash.net ([213.144.137.162]:57423 "EHLO stinky.trash.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752100Ab1ARPJc (ORCPT ); Tue, 18 Jan 2011 10:09:32 -0500 In-Reply-To: <1295183947-12786-6-git-send-email-fw@strlen.de> Sender: netfilter-devel-owner@vger.kernel.org List-ID: On 16.01.2011 14:19, Florian Westphal wrote: > If an skb is to be NF_QUEUE'd, but no program has opened the queue, the > packet is dropped. > > This adds a v2 target revision of xt_NFQUEUE that allows packets to > continue through the ruleset instead. > > Because the actual queueing happens outside of the target context, the > 'bypass' flag has to be communicated back to the netfilter core. > > Unfortunately the only choice to do this without adding a new function > argument is to use the target function return value (i.e. the verdict). > > In the NF_QUEUE case, the upper 16bit already contain the queue number > to use. The previous patch reduced NF_VERDICT_MASK to 0xff, i.e. > we now have extra room for a new flag. > > If a hook issued a NF_QUEUE verdict, then the netfilter core will > continue packet processing if the queueing hook > returns -ESRCH (== "this queue does not exist") and the new > NF_VERDICT_FLAG_QUEUE_BYPASS flag is set in the verdict value. > > Note: If the queue exists, but userspace does not consume packets fast > enough, the skb will still be dropped. Applied, thanks.