Subject: Re: [RFC PATCH v2 net-next 0/3] flow_offload: Re-add per-action statistics

From: Vlad Buslov <[email-masked]>
Date: Wed, 22 May 2019 17:49:53 +0000

On Wed 22 May 2019 at 20:24, Jamal Hadi Salim <[email-masked]> wrote:
> On 2019-05-22 11:08 a.m., Vlad Buslov wrote:
>>
>> On Tue 21 May 2019 at 16:23, Vlad Buslov <[email-masked]> wrote:
>
>>
>> It seems that culprit in this case is tc_action->order field. It is used
>> as nla attrtype when dumping actions. Initially it is set according to
>> ordering of actions of filter that creates them. However, it is
>> overwritten in tca_action_gd() each time action is dumped through action
>> API (according to action position in tb array) and when new filter is
>> attached to shared action (according to action order on the filter).
>> With this we have another way to reproduce the bug:
>>
>> sudo tc qdisc add dev lo ingress
>>
>> #shared action is the first action (order 1)
>> sudo tc filter add dev lo parent ffff: protocol ip prio 8 u32 \
>> match ip dst 127.0.0.8/32 flowid 1:10 \
>> action drop index 104 \
>> action vlan push id 100 protocol 802.1q
>>
>> #shared action is the the second action (order 2)
>> sudo tc filter add dev lo parent ffff: protocol ip prio 8 u32 \
>> match ip dst 127.0.0.10/32 flowid 1:10 \
>> action vlan push id 101 protocol 802.1q \
>> action drop index 104
>>
>> # Now action is only visible on one filter
>> sudo tc -s filter ls dev lo parent ffff: protocol ip
>>
>
> Ok, thanks for chasing this. A test case i had in mind is to
> maybe have 3 actions. Add the drop in the middle for one
> and at the begging for another and see if they are visible
> with the patch.
> If you dont have time I can test maybe AM tommorow.

Works with my patch:

~$ sudo tc qdisc del dev lo ingress
~$ sudo tc qdisc add dev lo ingress
~$ sudo tc filter add dev lo parent ffff: protocol ip prio 8 u32 \
> match ip dst 127.0.0.8/32 flowid 1:10 \
> action drop index 104 \
> mirred egress redirect dev ens1f0 \
> action vlan push id 100 protocol 802.1q
~$ sudo tc filter add dev lo parent ffff: protocol ip prio 8 u32 \
> match ip dst 127.0.0.10/32 flowid 1:10 \
> action vlan push id 101 protocol 802.1q \
> action drop index 104 \
> mirred egress redirect dev ens1f0
~$ sudo tc -s filter ls dev lo parent ffff: protocol ip
filter pref 8 u32 chain 0
filter pref 8 u32 chain 0 fh 800: ht divisor 1
filter pref 8 u32 chain 0 fh 800::800 order 2048 key ht 800 bkt 0 flowid 1:10 not_in_hw  (rule hit 0 success 0)
  match 7f000008/ffffffff at 16 (success 0 )
        action order 1: gact action drop
         random type none pass val 0
         index 104 ref 2 bind 2 installed 8 sec used 8 sec
        Action statistics:
        Sent 0 bytes 0 pkt (dropped 0, overlimits 0 requeues 0)
        backlog 0b 0p requeues 0

        action order 2: mirred (Egress Redirect to device ens1f0) stolen
        index 1 ref 1 bind 1 installed 8 sec used 8 sec
        Action statistics:
        Sent 0 bytes 0 pkt (dropped 0, overlimits 0 requeues 0)
        backlog 0b 0p requeues 0

        action order 3: vlan  push id 100 protocol 802.1Q priority 0 pipe
         index 1 ref 1 bind 1 installed 8 sec used 8 sec
        Action statistics:
        Sent 0 bytes 0 pkt (dropped 0, overlimits 0 requeues 0)
        backlog 0b 0p requeues 0

filter pref 8 u32 chain 0 fh 800::801 order 2049 key ht 800 bkt 0 flowid 1:10 not_in_hw  (rule hit 0 success 0)
  match 7f00000a/ffffffff at 16 (success 0 )
        action order 1: vlan  push id 101 protocol 802.1Q priority 0 pipe
         index 2 ref 1 bind 1 installed 4 sec used 4 sec
        Action statistics:
        Sent 0 bytes 0 pkt (dropped 0, overlimits 0 requeues 0)
        backlog 0b 0p requeues 0

        action order 2: gact action drop
         random type none pass val 0
         index 104 ref 2 bind 2 installed 8 sec used 8 sec
        Action statistics:
        Sent 0 bytes 0 pkt (dropped 0, overlimits 0 requeues 0)
        backlog 0b 0p requeues 0

        action order 3: mirred (Egress Redirect to device ens1f0) stolen
        index 2 ref 1 bind 1 installed 4 sec used 4 sec
        Action statistics:
        Sent 0 bytes 0 pkt (dropped 0, overlimits 0 requeues 0)
        backlog 0b 0p requeues 0