[ovs-discuss] query regarding outer ethernet header formation for gre encapsulated packet

[Jesse Gross]

It's configured by the user in port options using ovs-vsctl.

On Fri, Jan 23, 2015 at 3:45 AM, Mohit Malik <hr.mohit.malik at gmail.com> wrote:
> Thanks a lot, I really appreciate your response.
> Just 1 more query if you may help me with, how does OVS get the Dest-IP for
> tunneling endpoint in the tun_key attributes.
>
> Thnx
> Mohit
>
> On Thu, Jan 22, 2015 at 9:31 PM, Jesse Gross <jesse at nicira.com> wrote:
>>
>> On Thu, Jan 22, 2015 at 5:12 AM, Mohit Malik <hr.mohit.malik at gmail.com>
>> wrote:
>> > Hi,
>> >
>> > I am trying to understand the GRE encapsulation functionality of OVS. I
>> > have
>> > seen the flow of the packet in case of gre encapsulation, the flow is
>> > like
>> > :-
>> >
>> > do_output -> ovs_vport_send -> gre_send -> __send -> __build_header(to
>> > build
>> > gre header) + iptunnel_xmit(to build and send ip packet)
>> >
>> > So, in this flow I am not able to see the place in code, where outer
>> > ethernet frame is getting attached and also the place where packet is
>> > actually sent out.
>>
>> The packet is handed off to the Linux IP stack to be sent like any
>> other packet. Adding the Ethernet header is not part of OVS, it is
>> based on the routing table, ARP resolution, etc.
>
>