netdev - Re: [net-next PATCH 1/1] net_sched fix: reclassification needs to consider ether protocol changes

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Message-ID: <56C23C29.2060101@iogearbox.net>
Date:	Mon, 15 Feb 2016 21:59:21 +0100
From:	Daniel Borkmann <daniel@...earbox.net>
To:	Jamal Hadi Salim <jhs@...atatu.com>
CC:	davem@...emloft.net, netdev@...r.kernel.org
Subject: Re: [net-next PATCH 1/1] net_sched fix: reclassification needs to
 consider ether protocol changes

On 02/15/2016 08:49 PM, Jamal Hadi Salim wrote:
> From: Jamal Hadi Salim <jhs@...atatu.com>
>
> actions could change the etherproto in particular with ethernet
> tunnelled data. Typically such actions, after peeling the outer header,
> will ask for the packet to be  reclassified. We then need to restart
> the classification with the new proto header.
>
> Example setup used to catch this:
> sudo tc qdisc add dev $ETH ingress
> sudo tc filter add dev $ETH parent ffff: prio 2 protocol 0xbeef \
> u32 match u32 0 0 flowid 1:1 \
> action ife decode reclassify

ife action is out of tree, but I believe this should be possible with
vlan action and using reclassify as tc opcode.

> Fixes: 3b3ae880266d ("net: sched: consolidate tc_classify{,_compat}")
> Signed-off-by: Jamal Hadi Salim <jhs@...atatu.com>

Has kbuild bot issues, I'd probably just move this under 'reset' label,
like:

diff --git a/net/sched/sch_api.c b/net/sched/sch_api.c
index b5c2cf2..af1acf0 100644
--- a/net/sched/sch_api.c
+++ b/net/sched/sch_api.c
@@ -1852,6 +1852,7 @@ reset:
  	}

  	tp = old_tp;
+	protocol = tc_skb_protocol(skb);
  	goto reclassify;
  #endif
  }

Thanks,
Daniel