xdpcap support for IP-in-IP tunneled packets.

Hi,

Summary: I am trying to use xdpcap to capture the packets which have IP-in-IP additional header. I couldn't capture the packets with xdpcap.

Issue:
The packets structure is as follows
eth header + ip-ip tunnel header + ip header + tcp/udp header + data

Setup:
Source machine -> Proxy server( where xdpcap runs) -> destination

I am doing some processing in proxy server and apply XDP_TX on the data. I want to trace this data.

Can you suggest how to capture the packets?

Start by reproducing the reported proxy-server setup with an Ethernet header, IP-in-IP tunnel header, inner IP header, TCP or UDP header, and data. Investigate how xdpcap handles these packets after XDP_TX, and consider the work complete when tunneled packets can be captured reliably in this setup.

Written by the indexing model from the issue text.