[net-next,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@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 <jhs@mojatatu.com>

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


Thanks,
Daniel

On 16-02-15 03:59 PM, Daniel Borkmann wrote:
> On 02/15/2016 08:49 PM, Jamal Hadi Salim wrote:
>> From: Jamal Hadi Salim <jhs@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.
>

Ok, let me do some test with vlan example.(Note: Caught this when i was
trying to test the IFE code for submission on the flight home).

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


The polite bot is confused in its report. I had to look at .config to
figure it out. I guess this is the point where human intervention is
needed. Basically the problem is it turned off CONFIG_NET_CLS_ACT
and recompiled; for a second i thought it was i386 specific.
I will juggle things around to make it happy.

cheers,
jamal


> Thanks,
> Daniel