[ovs-dev] [PATCH v8 5/5] datapath: add layer 3 support to ovs_packet_cmd_execute()

Jesse Gross jesse at nicira.com
Mon Nov 17 23:36:40 UTC 2014


On Mon, Nov 17, 2014 at 2:37 PM, Lori Jakab <lojakab at cisco.com> wrote:
> On 11/18/14 12:33 AM, Jesse Gross wrote:
>>
>> On Mon, Nov 17, 2014 at 1:50 PM, Lori Jakab <lojakab at cisco.com> wrote:
>>>
>>> On 11/17/14 8:03 PM, Jesse Gross wrote:
>>>>
>>>> On Mon, Nov 17, 2014 at 9:24 AM, Lorand Jakab <lojakab at cisco.com> wrote:
>>>>>
>>>>> diff --git a/datapath/flow_netlink.c b/datapath/flow_netlink.c
>>>>> index 54510c8..8ca3469 100644
>>>>> --- a/datapath/flow_netlink.c
>>>>> +++ b/datapath/flow_netlink.c
>>>>> @@ -692,6 +692,18 @@ static int metadata_from_nlattrs(struct
>>>>> sw_flow_match *match,  u64 *attrs,
>>>>>                   else
>>>>>                           SW_FLOW_KEY_PUT(match, phy.is_layer3, true,
>>>>> is_mask);
>>>>>           }
>>>>> +       /* Layer 3 packets from user space have the EtherType as
>>>>> metadata
>>>>> */
>>>>> +       if (*attrs & (1ULL << OVS_KEY_ATTR_ETHERTYPE)) {
>>>>
>>>> Is this correct? I thought that EtherType wasn't serialized in this
>>>> case - in other places we extract this from the IP/IPv6 attribute
>>>> directly.
>>>
>>>
>>> For "ovs_flow" Netlink messages we can do that, but not for "ovs_packet"
>>> messages, which only have packet metadata, not the full flow key.  Packet
>>> metadata didn't include EtherType until now, but I unless we use the
>>> nibble
>>> from the IP version, we need to add it for layer 3 packets only.
>>
>> Hmm, I see. I think that diverging the Netlink encoding for flow
>> installation vs. metadata is probably not a good idea over the long
>> term. If I remember correctly, I believe the reason for only encoding
>> part of the flow key for metadata was to reduce serialization cost.
>> Jarno is thinking about combining the packet execution with flow
>> installation, which would might make this a moot point. If that's the
>> case, then we can probably solve this issue by just using the full
>> flow key.
>
> OK, how should I proceed then?  Should I wait until that work lands in
> master?

I don't know the current status of that work, maybe Jarno can let you
know. I think he also might have made the original change to only send
the metadata so might have some of the history there. Perhaps we can
just undo that change if we expect that it will be addressed soon.



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