1#!/usr/bin/env python3.6
2#
3# Copyright (c) 2013-2018 by Ron Frederick <ronf@timeheart.net> and others.
4#
5# This program and the accompanying materials are made available under
6# the terms of the Eclipse Public License v2.0 which accompanies this
7# distribution and is available at:
8#
9#     http://www.eclipse.org/legal/epl-2.0/
10#
11# This program may also be made available under the following secondary
12# licenses when the conditions for such availability set forth in the
13# Eclipse Public License v2.0 are satisfied:
14#
15#    GNU General Public License, Version 2.0, or any later versions of
16#    that license
17#
18# SPDX-License-Identifier: EPL-2.0 OR GPL-2.0-or-later
19#
20# Contributors:
21#     Ron Frederick - initial implementation, API, and documentation
22
23# To run this program, the file ``ssh_host_key`` must exist with an SSH
24# private key in it to use as a server host key. An SSH host certificate
25# can optionally be provided in the file ``ssh_host_key-cert.pub``.
26#
27# The file ``ssh_user_ca`` must exist with a cert-authority entry of
28# the certificate authority which can sign valid client certificates.
29
30import asyncio, asyncssh, sys
31
32class MySSHServer(asyncssh.SSHServer):
33    def connection_requested(self, dest_host, dest_port, orig_host, orig_port):
34        if dest_port == 80:
35            return True
36        else:
37            raise asyncssh.ChannelOpenError(
38                      asyncssh.OPEN_ADMINISTRATIVELY_PROHIBITED,
39                      'Only connections to port 80 are allowed')
40
41async def start_server():
42    await asyncssh.create_server(MySSHServer, '', 8022,
43                                 server_host_keys=['ssh_host_key'],
44                                 authorized_client_keys='ssh_user_ca')
45
46loop = asyncio.get_event_loop()
47
48try:
49    loop.run_until_complete(start_server())
50except (OSError, asyncssh.Error) as exc:
51    sys.exit('SSH server failed: ' + str(exc))
52
53loop.run_forever()
54