SCTP mode supported

[liudf0716]

xfrpc currently does not support STCP, and we are in need of assistance to implement it. As stated in the frp documentation, 'STCP' is described as:

Expose your service privately
Some services will be at risk if exposed directly to the public network. With STCP (secret TCP) mode, a preshared key is needed to access the service from another client.

Configure frps same as above.

Start frpc on machine B with the following config. This example is for exposing the SSH service (port 22), and note the sk field for the preshared key, and that the remote_port field is removed here:

frpc.ini

[common]
server_addr = x.x.x.x
server_port = 7000

[secret_ssh]
type = stcp
sk = abcdefg
local_ip = 127.0.0.1
local_port = 22
Start another frpc (typically on another machine C) with the following config to access the SSH service with a security key (sk field):

frpc.ini

[common]
server_addr = x.x.x.x
server_port = 7000

[secret_ssh_visitor]
type = stcp
role = visitor
server_name = secret_ssh
sk = abcdefg
bind_addr = 127.0.0.1
bind_port = 6000
On machine C, connect to SSH on machine B, using this command:
ssh -oPort=6000 127.0.0.1