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

[Jarno Rajahalme]

On Nov 20, 2014, at 12:18 PM, Jesse Gross <jesse at nicira.com> wrote:

> On Thu, Nov 20, 2014 at 10:35 AM, Jarno Rajahalme <jrajahalme at nicira.com> wrote:
>> The netlink key for flow put is serialized from struct flow, so even in the
>> case of L3 the ethertype would be serialized.
>> 
>> Even the kernel datapath is encoding the ethertype in key_extract(), even
>> when it is not in the packet:
>> 
>> + /* Link layer. */
>> + if (key->phy.is_layer3) {
>> + key->eth.tci = 0;
>> + key->eth.type = skb->protocol;
>> + } else {
>> 
>> So I guess you are not saying that the ethertype should not be serialized,
>> due to it not being in the L3 packet?
> 
> The EtherType is stored in the flow key for efficiency but it is
> actually not part of the serialized netlink representation currently.

OK, I see patch 2/5 skipping past the line where dl_type is serialized in odp-util.c. 

> This revision of the series introduces a patch to change the
> serialization from userspace for the purposes of packet execution but
> it is not done from the kernel or at all in previous revisions. I
> think it is important that userspace, kernel, and the data contained
> in the packet line up as closely as possible.


So by encoding the whole key the datapath can detect the presence of OVS_KEY_ATTR_IPV4 or OVS_KEY_ATTR_IPV6 and use those to set the skb->protocol?

  Jarno