netdev - Re: [tproxy,regression] tproxy broken in 2.6.32

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Date:	Sat, 28 Nov 2009 10:45:57 -0500
From:	jamal <hadi@...erus.ca>
To:	KOVACS Krisztian <hidden@....bme.hu>
Cc:	KOVACS Krisztian <hidden@...abit.hu>,
	Andreas Schultz <aschultz@...p10.net>, tproxy@...ts.balabit.hu,
	netdev@...r.kernel.org
Subject: Re: [tproxy,regression] tproxy broken in 2.6.32

On Sat, 2009-11-28 at 16:15 +0100, KOVACS Krisztian wrote:


> It's already on prerouting, so that's not the problem.

ok.

> The problem is that for tproxy to work we've used to have a rule like
> this:
> 
> # ip rule add fwmark 1 lookup 100
> 
> plus a few iptables rules setting mark values.
> 
> The issue is that previously fib_validate_source ignored the mark set on
> the skb, and thus when fib_validate_source() did a FIB lookup, it all went
> fine, because it found a result of type RTN_UNICAST.


Ok, that would be it ;-> 


>  However, with your
> change, and because of the ip rule above not being specific enough now
> it's returning with type RTN_LOCAL, and that's considered invalid and thus
> the skb is dropped.

Well, since we are validating a source address - only unicast routes
are legitimate imo. i.e it was wrong to allow local before.

> 
> The workaround is using more specific ip rules that include the ingress
> interface name:
> 
> # ip rule add dev eth0 fwmark 1 lookup 100
> 

Or adding routes into table 100 with type "unicast" would do it as
well.

cheers,
jamal

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