[FEATURE] Bind to interface

[slldev]

Hello, nice module. Something myself and presumably others would benefit from is being able to bind to specific interface, using

sock.setsockopt(
                socket.SOL_SOCKET,
                socket.SO_BINDTODEVICE,
               {interface}),
            )

I took a look at protocol.py and didn't immediately see a way to implement this. Any guidance?

[Amaindex]

Hi @slldev, thank you for your issue.

I have thought about this point. Although I haven't solved it, some of my thoughts and discoveries may help you:

• There is a saying (although I don't know if this is correct) that the SOCKS works at the transport layer, so it should deal with network layer concepts, such as IP addresses, rather than concepts at the lower level, such as interface, etc.
• In many cases, if you want to force SOCKS to use a particular network interface, you can do this by binding the socket to the ip of the network interface. For asyncio-socks-server, you can specify the host and port parameters of loop.create_server at here and the local_addr parameters of loop.create_connection at here.
• The asyncio module does not provide an API to set the socket-opt, but it is implemented based on Python's socket object. You can set the socket-opt for the object, but I am not sure if this will bring unpredictable side effects because I do not fully understand the implementation of asyncio🤣.