Feature Request: Chain Shadowsocks

[PowerPress]

Is your feature request related to a problem? Please describe.
I would like to create a chain of shadowsocks servers like proxychains
client - ss server - ss server - ss server - ss server -target

Describe the solution you'd like
Have a chain option in shadowsocks

[zonyitoo]

You can do this with a tunnel:

sslocal(real) -> [sslocal(tunnel) -> ssserver] -> [sslocal(tunnel) -> ssserver] -> ssserver(real)

[PowerPress]

Could you give me an example of commands to do this?

[zonyitoo]

Let's say if you have a server running on 100.100.100.200:1234, and there is a server in the middle listening on 100.100.100.101:2345, then:

Local server:

sslocal -b '127.0.0.1:1080' -s '100.100.100.101:2345' -m 'aes-128-gcm' -k 'TARGET_SERVER_PWD'

Middle server:

# Start a sslocal with tunnel protocol, forwarding all data to 100.100.100.200:1234
sslocal -b '100.100.100.101:2345' --protocol tunnel -s '127.0.0.1:8888' -m 'plain' -k '' --forward-addr '100.100.100.200:1234'

# Start a ssserver locally
ssserver -b '127.0.0.1:8888' -m 'plain' -k ''

Target server:

ssserver -s '100.100.100.200:1234' -m 'aes-128-gcm' -k 'TARGET_SERVER_PWD'

BUT. This is slow, because all the middle servers must run both sslocal and ssserver. Actually you can simply make a dummy TCP, UDP tunnel proxy server with any languages you want:

sslocal -> [Tunnel Proxy server 1] -> [Tunnel Proxy server 2] -> ssserver

Some possible choices:

1. v2ray-plugin, running in standalone mode
2. https://github.com/Qv2ray/mmp-go

[peterwillcn]

Implement port hopping

Users in China sometimes report that their ISPs block or throttle persistent UDP connections. However, these restrictions often only apply to the specific port being used. Port hopping can be used as a workaround for this situation.