By design, VRFs allow route-leaking for forwarded packages, but not for local processes using a socket. While it was possible to leak such TCP traffic through a VRF on a 4.x kernel, this behavior was considered wrong and got fixed in Linux 5.x[1]. From now on, local unix sockets must run in the VRF itself using `ip vrf exec`[2] which basically injects a BPF program into the VRF and drops elevated networking capabilities by default for the specified command. [1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=3c82a21f4320c8d54cf6456b27c8d49e5ffb722e [2] https://man7.org/linux/man-pages/man8/ip-vrf.8.html
The subtest was mainly written to demonstrate the VRF-issues with a 5.x-kernel. However this breaks the entire test now as we have 5.4 as default kernel. Disabling the test for now, I still need to find some time to investigate.