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

[Daniel Borkmann]

On 02/15/2016 08:49 PM, Jamal Hadi Salim wrote:

From: Jamal Hadi Salim <j...@mojatatu.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 <j...@mojatatu.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