netdev - Re: [v8 PATCH 2/3] NETFILTER module xt_hmark, new target for HASH based fwmark

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Date:	Thu, 9 Feb 2012 19:32:03 +0100
From:	Hans Schillstrom <hans@...illstrom.com>
To:	Pablo Neira Ayuso <pablo@...filter.org>
Cc:	Hans Schillstrom <hans.schillstrom@...csson.com>, kaber@...sh.net,
	jengelh@...ozas.de, netfilter-devel@...r.kernel.org,
	netdev@...r.kernel.org
Subject: Re: [v8 PATCH 2/3] NETFILTER module xt_hmark, new target for HASH based fwmark


On Wednesday, February 08, 2012 01:27:43 Pablo Neira Ayuso wrote:
> On Fri, Jan 27, 2012 at 03:41:42PM +0100, Hans Schillstrom wrote:
[snip]

> > +#if defined(CONFIG_NF_NAT)
> > +	if (ct && test_bit(IP_CT_IS_REPLY, &ct->status)) {
> > +		struct nf_conntrack_tuple *otuple;
> > +
> > +		otuple = &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple;
> > +		/*
> > +		 * On the "return flow", to get the original address
> > +		 */
> > +		if ((ct->status & IPS_DST_NAT) &&
> > +			(info->flags & XT_HMARK_USE_DNAT)) {
> > +			addr1 = (__force u32) otuple->dst.u3.in.s_addr;
> > +			dnatport = otuple->dst.u.udp.port;
> > +		}
> > +		if ((ct->status & IPS_SRC_NAT) &&
> > +			(info->flags & XT_HMARK_USE_SNAT)) {
> > +			addr2 = (__force u32) otuple->src.u3.in.s_addr;
> > +			snatport = otuple->src.u.udp.port;
> > +		}
> 
> You can make this much more simple.
> 
> Allow the user to tell your HMARK target to use the conntrack
> information instead.
> 
> My opinion is that the user must have total control on the target
> behaviour through the configuration options. The number of internal
> by-default decisions have to be kept up to the minimum, otherwise
> the behaviour of the target may seem obscure.
> 
> > +	}
> > +#endif
> > +	/* user space tool ensures that prmask is zero when method is L3*/

While dealing with fragmentation in ipvs, an idea run into my head...
why not take care of fragments from nfct_reasm in L3_4 mode ?

OK it might be an obscure behaviour but on the other hand
people expect that fragments is handled by netfilter...


/Hans
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