[net-next PATCH v2 1/1] net_sched fix: reclassification needs to consider ether protocol changes

[net-next PATCH v2 1/1] net_sched fix: reclassification needs to consider ether protocol changes

[Jamal Hadi Salim]

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: pref 1 protocol 802.1Q \
u32 match u32 0 0 flowid 1:1 \
action vlan pop reclassify

Fixes: 3b3ae880266d ("net: sched: consolidate tc_classify{,_compat}")
Signed-off-by: Jamal Hadi Salim <jhs@mojatatu.com>
---
 net/sched/sch_api.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/net/sched/sch_api.c b/net/sched/sch_api.c
index b5c2cf2..22ab634 100644
--- a/net/sched/sch_api.c
+++ b/net/sched/sch_api.c
@@ -1818,13 +1818,14 @@ done:
 int tc_classify(struct sk_buff *skb, const struct tcf_proto *tp,
 		struct tcf_result *res, bool compat_mode)
 {
-	__be16 protocol = tc_skb_protocol(skb);
 #ifdef CONFIG_NET_CLS_ACT
-	const struct tcf_proto *old_tp = tp;
 	int limit = 0;
+#endif
+	const struct tcf_proto *old_tp = tp;
+	__be16 protocol;
 
 reclassify:
-#endif
+	protocol = tc_skb_protocol(skb);
 	for (; tp; tp = rcu_dereference_bh(tp->next)) {
 		int err;
 
-- 
1.9.1

Re: [net-next PATCH v2 1/1] net_sched fix: reclassification needs to consider ether protocol changes

[Daniel Borkmann]

On 02/16/2016 01:37 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: pref 1 protocol 802.1Q \
> u32 match u32 0 0 flowid 1:1 \
> action vlan pop reclassify
>
> Fixes: 3b3ae880266d ("net: sched: consolidate tc_classify{,_compat}")
> Signed-off-by: Jamal Hadi Salim <jhs@mojatatu.com>
> ---
>   net/sched/sch_api.c | 7 ++++---
>   1 file changed, 4 insertions(+), 3 deletions(-)
>
> diff --git a/net/sched/sch_api.c b/net/sched/sch_api.c
> index b5c2cf2..22ab634 100644
> --- a/net/sched/sch_api.c
> +++ b/net/sched/sch_api.c
> @@ -1818,13 +1818,14 @@ done:
>   int tc_classify(struct sk_buff *skb, const struct tcf_proto *tp,
>   		struct tcf_result *res, bool compat_mode)
>   {
> -	__be16 protocol = tc_skb_protocol(skb);
>   #ifdef CONFIG_NET_CLS_ACT
> -	const struct tcf_proto *old_tp = tp;
>   	int limit = 0;
> +#endif
> +	const struct tcf_proto *old_tp = tp;
> +	__be16 protocol;
>
>   reclassify:
> -#endif
> +	protocol = tc_skb_protocol(skb);
>   	for (; tp; tp = rcu_dereference_bh(tp->next)) {
>   		int err;
>

But, how is that better than the one-liner I suggested to you in
my earlier mail?

With this patch, I now get :

   CC      net/sched/sch_api.o
net/sched/sch_api.c: In function ‘tc_classify’:
net/sched/sch_api.c:1827:1: warning: label ‘reclassify’ defined but not used [-Wunused-label]
  reclassify:
  ^
net/sched/sch_api.c:1824:26: warning: unused variable ‘old_tp’ [-Wunused-variable]
   const struct tcf_proto *old_tp = tp;
                           ^
Thanks,
Daniel

Re: [net-next PATCH v2 1/1] net_sched fix: reclassification needs to consider ether protocol changes

[Jamal Hadi Salim]

On 16-02-16 10:20 AM, Daniel Borkmann wrote:
> On 02/16/2016 01:37 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: pref 1 protocol 802.1Q \
>> u32 match u32 0 0 flowid 1:1 \
>> action vlan pop reclassify
>>
>> Fixes: 3b3ae880266d ("net: sched: consolidate tc_classify{,_compat}")
>> Signed-off-by: Jamal Hadi Salim <jhs@mojatatu.com>
>> ---
>>   net/sched/sch_api.c | 7 ++++---
>>   1 file changed, 4 insertions(+), 3 deletions(-)
>>
>> diff --git a/net/sched/sch_api.c b/net/sched/sch_api.c
>> index b5c2cf2..22ab634 100644
>> --- a/net/sched/sch_api.c
>> +++ b/net/sched/sch_api.c
>> @@ -1818,13 +1818,14 @@ done:
>>   int tc_classify(struct sk_buff *skb, const struct tcf_proto *tp,
>>           struct tcf_result *res, bool compat_mode)
>>   {
>> -    __be16 protocol = tc_skb_protocol(skb);
>>   #ifdef CONFIG_NET_CLS_ACT
>> -    const struct tcf_proto *old_tp = tp;
>>       int limit = 0;
>> +#endif
>> +    const struct tcf_proto *old_tp = tp;
>> +    __be16 protocol;
>>
>>   reclassify:
>> -#endif
>> +    protocol = tc_skb_protocol(skb);
>>       for (; tp; tp = rcu_dereference_bh(tp->next)) {
>>           int err;
>>
>
> But, how is that better than the one-liner I suggested to you in
> my earlier mail?
>

Thats how the original code was (and what i tested). I dont have time
to test right now but i will send an update with your suggestion.

cheers,
jamal

Re: [net-next PATCH v2 1/1] net_sched fix: reclassification needs to consider ether protocol changes

[Jamal Hadi Salim]

On 16-02-17 06:19 AM, Jamal Hadi Salim wrote:

> Thats how the original code was (and what i tested). I dont have time
> to test right now but i will send an update with your suggestion.
>

My setup was still running so I managed to test it with IFE

cheers,
jamal

Re: [net-next PATCH v2 1/1] net_sched fix: reclassification needs to consider ether protocol changes

[Jamal Hadi Salim]

On 16-02-18 06:53 AM, Daniel Borkmann wrote:
> On 02/17/2016 06:27 PM, Cong Wang wrote:

>>>          const struct tcf_proto *old_tp = tp;
>>>          int limit = 0;
>>> -
>>
>> Why remove this empty line? I think it is still useful. :)
>>
>> Also your patch should be targeted to -net instead of -net-next, since it
>> fixes a bug.
>
> Yeah, good point. That should go to -net (minus the unrelated white
> space change).
>


One patch coming right up boys;->

cheers,
jamal

Re: [net-next PATCH v2 1/1] net_sched fix: reclassification needs to consider ether protocol changes

[Daniel Borkmann]

On 02/17/2016 06:27 PM, Cong Wang wrote:
> On Wed, Feb 17, 2016 at 3:37 AM, Jamal Hadi Salim <jhs@mojatatu.com> 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: pref 1 protocol 802.1Q \
>> u32 match u32 0 0 flowid 1:1 \
>> action  vlan pop reclassify
>>
>> Fixes: 3b3ae880266d ("net: sched: consolidate tc_classify{,_compat}")
>> Signed-off-by: Jamal Hadi Salim <jhs@mojatatu.com>
>> ---
>>   net/sched/sch_api.c | 2 +-
>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/net/sched/sch_api.c b/net/sched/sch_api.c
>> index b5c2cf2..af46fee 100644
>> --- a/net/sched/sch_api.c
>> +++ b/net/sched/sch_api.c
>> @@ -1822,7 +1822,6 @@ int tc_classify(struct sk_buff *skb, const struct tcf_proto *tp,
>>   #ifdef CONFIG_NET_CLS_ACT
>>          const struct tcf_proto *old_tp = tp;
>>          int limit = 0;
>> -
>
> Why remove this empty line? I think it is still useful. :)
>
> Also your patch should be targeted to -net instead of -net-next, since it
> fixes a bug.

Yeah, good point. That should go to -net (minus the unrelated white space change).

Thanks,
Daniel

Re: [net-next PATCH v2 1/1] net_sched fix: reclassification needs to consider ether protocol changes

[Cong Wang]

On Wed, Feb 17, 2016 at 3:37 AM, Jamal Hadi Salim <jhs@mojatatu.com> 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: pref 1 protocol 802.1Q \
> u32 match u32 0 0 flowid 1:1 \
> action  vlan pop reclassify
>
> Fixes: 3b3ae880266d ("net: sched: consolidate tc_classify{,_compat}")
> Signed-off-by: Jamal Hadi Salim <jhs@mojatatu.com>
> ---
>  net/sched/sch_api.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/net/sched/sch_api.c b/net/sched/sch_api.c
> index b5c2cf2..af46fee 100644
> --- a/net/sched/sch_api.c
> +++ b/net/sched/sch_api.c
> @@ -1822,7 +1822,6 @@ int tc_classify(struct sk_buff *skb, const struct tcf_proto *tp,
>  #ifdef CONFIG_NET_CLS_ACT
>         const struct tcf_proto *old_tp = tp;
>         int limit = 0;
> -

Why remove this empty line? I think it is still useful. :)

Also your patch should be targeted to -net instead of -net-next, since it
fixes a bug.

Thanks.

[net-next PATCH v2 1/1] net_sched fix: reclassification needs to consider ether protocol changes

[Jamal Hadi Salim]

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: pref 1 protocol 802.1Q \
u32 match u32 0 0 flowid 1:1 \
action  vlan pop reclassify

Fixes: 3b3ae880266d ("net: sched: consolidate tc_classify{,_compat}")
Signed-off-by: Jamal Hadi Salim <jhs@mojatatu.com>
---
 net/sched/sch_api.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/sched/sch_api.c b/net/sched/sch_api.c
index b5c2cf2..af46fee 100644
--- a/net/sched/sch_api.c
+++ b/net/sched/sch_api.c
@@ -1822,7 +1822,6 @@ int tc_classify(struct sk_buff *skb, const struct tcf_proto *tp,
 #ifdef CONFIG_NET_CLS_ACT
 	const struct tcf_proto *old_tp = tp;
 	int limit = 0;
-
 reclassify:
 #endif
 	for (; tp; tp = rcu_dereference_bh(tp->next)) {
@@ -1852,6 +1851,7 @@ reset:
 	}
 
 	tp = old_tp;
+	protocol = tc_skb_protocol(skb);
 	goto reclassify;
 #endif
 }
-- 
1.9.1