From: Mingyi Zhang <zhangmingyi5@xxxxxxxxxx>
Note that tcp_getsockopt and tcp_setsockopt support TCP_ULP, while
bpf_getsockopt and bpf_setsockopt do not support TCP_ULP.
I think we can add the handling of this case.
We want call bpf_setsockopt to replace the kernel module in the TCP_ULP
case. The purpose is to customize the behavior in connect and sendmsg.
We have an open source community project kmesh (kmesh.net). Based on
this, we refer to some processes of tcp fastopen to implement delayed
connet and perform HTTP DNAT when sendmsg.In this case, we need to parse
HTTP packets in the bpf program and set TCP_ULP for the specified socket.