Get the latest tech news
eBPF Mystery: When is IPv4 not IPv4? When it's pretending to be IPv6
Code, Apps and Thoughts @lawrencegripper
This was invaluable for tracking down this bug, without them, it would be very hard to reason about what was happening inside the eBPF portion of the progam. Running the repro steps dotnet add package x with the above hook, I was immediately greeted by connect6 being hit, even though wireshark showed IPv4 traffic exiting the VM. My wireshark traces didn’t see the IPv6 traffic, as the kernel is translating it back to IPv4 when making the networking call, so this interim state is only visible to the eBPF programs/kernel.
Or read this on Hacker News