netdev - Re: Ingress tc filters with IPSec

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Date:	Sat, 30 May 2015 02:24:51 -0400
From:	"John A. Sullivan III" <jsullivan@...nsourcedevel.com>
To:	netdev@...r.kernel.org
Subject: Re: Ingress tc filters with IPSec

On Sat, 2015-05-30 at 01:52 -0400, John A. Sullivan III wrote:
> Argh! yet another obstacle from my ignorance.  We are attempting ingress
> traffic shaping using IFB interfaces on traffic coming via GRE / IPSec.
> Filters and hash tables are working fine with plain GRE including
> stripping the header.  We even got the ematch filter working so that the
> ESP packets are the only packets not redirected to IFB.
> 
> But, regardless of whether we redirect ESP packets to IFB, the filters
> never see the decrypted packets.  I thought the packets passed through
> the interface twice - first encrypted and they decrypted.  However,
> tcpdump only shows the ESP packets on the interface.
> 
> How do we apply filters to the packets after decryption? Thanks - John

I see what changed.  In the past, this seemed to work but we were using
tunnel mode.  We were trying to use transport mode in this application
but that seems to prevent the decrypted packet contents from appearing
again on the interface.  Reverting to tunnel mode made the contents
visible again and our filters are working as expected - John

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