Subject: Re: [PATCH net-next V17 3/3] 802.1AD: Flow handling, actions, vlan parsing and netlink attributes

From: Thomas F Herbert <[email-masked]>
Date: Tue, 20 Oct 2015 10:26:26 -0400

On 10/19/15 2:28 PM, Pravin Shelar wrote:
> On Sat, Oct 17, 2015 at 6:12 PM, Thomas F Herbert
> <[email-masked]> wrote:
>> Add support for 802.1ad including the ability to push and pop double
>> tagged vlans. Add support for 802.1ad to netlink parsing and flow
>> conversion. Uses double nested encap attributes to represent double
>> tagged vlan. Inner TPID encoded along with ctci in nested attributes.
>>
>> Signed-off-by: Thomas F Herbert <[email-masked]>
>> ---
>>   net/openvswitch/actions.c      |   6 +-
>>   net/openvswitch/flow.c         |  76 +++++++++++++-----
>>   net/openvswitch/flow.h         |   8 +-
>>   net/openvswitch/flow_netlink.c | 172 +++++++++++++++++++++++++++++++++++++----
>>   net/openvswitch/vport-netdev.c |   4 +-
>>   5 files changed, 227 insertions(+), 39 deletions(-)
>>
>> diff --git a/net/openvswitch/actions.c b/net/openvswitch/actions.c
>> index 315f533..09cc1c9 100644
> ...
>
>> diff --git a/net/openvswitch/flow_netlink.c b/net/openvswitch/flow_netlink.c
>> index c92d6a2..97a6d12 100644
>> --- a/net/openvswitch/flow_netlink.c
>> +++ b/net/openvswitch/flow_netlink.c
> ...
>
>> @@ -1320,6 +1443,7 @@ static int __ovs_nla_put_key(const struct sw_flow_key *swkey,
>>   {
>>          struct ovs_key_ethernet *eth_key;
>>          struct nlattr *nla, *encap;
>> +       struct nlattr *in_encap = NULL;
>>
>>          if (nla_put_u32(skb, OVS_KEY_ATTR_RECIRC_ID, output->recirc_id))
>>                  goto nla_put_failure;
>> @@ -1368,17 +1492,29 @@ static int __ovs_nla_put_key(const struct sw_flow_key *swkey,
>>          ether_addr_copy(eth_key->eth_src, output->eth.src);
>>          ether_addr_copy(eth_key->eth_dst, output->eth.dst);
>>
>> -       if (swkey->eth.tci || swkey->eth.type == htons(ETH_P_8021Q)) {
>> -               __be16 eth_type;
>> -               eth_type = !is_mask ? htons(ETH_P_8021Q) : htons(0xffff);
>> -               if (nla_put_be16(skb, OVS_KEY_ATTR_ETHERTYPE, eth_type) ||
>> -                   nla_put_be16(skb, OVS_KEY_ATTR_VLAN, output->eth.tci))
>> +       if (swkey->eth.vlan.tci || eth_type_vlan(swkey->eth.type)) {
>> +               if (nla_put_be16(skb, OVS_KEY_ATTR_ETHERTYPE,
>> +                                output->eth.vlan.tpid) ||
>> +                   nla_put_be16(skb, OVS_KEY_ATTR_VLAN, output->eth.vlan.tci))
>>                          goto nla_put_failure;
>>                  encap = nla_nest_start(skb, OVS_KEY_ATTR_ENCAP);
>> -               if (!swkey->eth.tci)
>> +               if (!swkey->eth.vlan.tci)
>>                          goto unencap;
>> -       } else
>> +               if (swkey->eth.cvlan.tci) {
>> +                       /* Customer tci is nested but uses same key attribute.
>> +                        */
>> +                       if (nla_put_be16(skb, OVS_KEY_ATTR_ETHERTYPE,
>> +                                        output->eth.cvlan.tpid) ||
>> +                           nla_put_be16(skb, OVS_KEY_ATTR_VLAN,
>> +                                        output->eth.cvlan.tci))
>> +                               goto nla_put_failure;
>> +                       in_encap = nla_nest_start(skb, OVS_KEY_ATTR_ENCAP);
>> +                       if (!swkey->eth.cvlan.tci)
>> +                               goto unencap;
>> +               }
>> +       } else {
>>                  encap = NULL;
>> +       }
> After the vlan parsing changes, we need to encode cvlan in outer
> netlink attribute and then encode regular vlan.
I don't understand this. cvlan is inner vlan, why would it be encoded in 
outer vlan without the 2nd layer of encapsulation?

One think I see I should have done is check for eth_type_vlan() on the 
inner tag as well.
> Currently we are
> reversing netlink encoding while sending back the vlan attributes.
> cvlan and vlan is independent,
Are you talking about a corner case where the incoming packet has an 
inner vlan but no outer vlN?
> therefore we need to check
> swkey->eth.cvlan.tc outside of swkey->eth.vlan.tci block. Also
> redundant check for swkey->eth.cvlan.tci should be removed
I must be missing something because I don't understand this either. 
First my patch encodes the outer vlan and then sets the encap bit and 
then encodes the inner vlan. The encoding shows up correctly in user space.
>
> Can you also post changes for userspace vswitchd so that I can try next patch.
I posted a patch for user space (V14) to ovs dev on October 2nd. I 
haven't made any changes since then.
http://openvswitch.org/pipermail/dev/2015-October/060874.html