bpf: perform l4 dnat on health service vip to backend port
bpf: perform l4 dnat on health service vip to backend port

Given the order is bind() + connect(), rewrite the destination port
to the backend if it doesn't match the service VIP. Implement this
for pure v4 and v6 sockets.

Signed-off-by: Daniel Borkmann <3d0f3b9ddcacec30c4008c5e030e6c13a478cb4f@iogearbox.net>

cilium/cilium,tgraf/cilium,tklauser/cilium,michi-covalent/cilium,michi-covalent/cilium,cilium/cilium,tgraf/cilium,tgraf/cilium,michi-covalent/cilium,michi-covalent/cilium,tklauser/cilium,michi-covalent/cilium,tklauser/cilium,cilium/cilium,tgraf/cilium,tklauser/cilium,tgraf/cilium,tklauser/cilium,cilium/cilium,tgraf/cilium,cilium/cilium