Properly handle AF_INET6 requests

Socket addresses in the Python socket interface are represented in
multiple different ways according to the socket family. Both AF_INET and
AF_INET6 families use tuples with the host as the first element.

Currently we extract the host from the first element of such a tuple,
and ignore the other element. Since AF_INET6 has four elements, this
will fail with a ValueError.

To support AF_INET6 requests, make sure to store whatever is left of the
tuple in a list instead.

untls_proxy.py

@@ -431,7 +431,7 @@ def listen(port):
 	while True:
 		for fd, _ in listening.poll():
 			# TODO: Threads
-			conn, (host, _) = sock_by_fd[fd].accept()
+			conn, (host, *_) = sock_by_fd[fd].accept()
 			proxy(conn, host)
 			conn.close()