Connection over existing non-TCP socket fails

[cwe-skov-dk]

I use asyncssh 2.17.0 to connect a server using an established WebRTC tunnel. To connect the tunnel and asyncssh I create a socket.socketpair() and use one end of the pair inside asyncssh.connect() as sock argument.

This ends in a failure in sock.setsockopt(socket.IPPROTO_TCP, socket.TCP_NODELAY, 1) inside connection_made() in asyncssh connection.py line 1275.

Adding a test for sock.family fixes the issue and the connection is established correctly using the socketpair socket:

        if sock:
            sock.setsockopt(socket.SOL_SOCKET, socket.SO_KEEPALIVE,
                            self._tcp_keepalive)
            if sock.family in {socket.AF_INET, socket.AF_INET6}:
                sock.setsockopt(socket.IPPROTO_TCP, socket.TCP_NODELAY, 1)

[ronf]

This change makes sense - I'll add it in as soon as I'm done with another change I'm in the middle of.

Thanks for the report!

[ronf]

This is now available as commit dcd1c61 in the "develop" branch.

Note that you will still want to pass in a host and port when making the asyncssh.connect() call. Otherwise, things like the known hosts lookup may fail to find the right entry for the server you are connecting to.

[cwe-skov-dk]

Thanks a lot!

Yes, I know about the hostname and do pass that to asyncssh.connect() in my implementation.