#!/usr/bin/env python
# vim: tabstop=4 shiftwidth=4 softtabstop=4

# Copyright (c) 2012 OpenStack, LLC.
# All Rights Reserved.
#
#    Licensed under the Apache License, Version 2.0 (the "License"); you may
#    not use this file except in compliance with the License. You may obtain
#    a copy of the License at
#
#         http://www.apache.org/licenses/LICENSE-2.0
#
#    Unless required by applicable law or agreed to in writing, software
#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
#    License for the specific language governing permissions and limitations
#    under the License.

'''
Websocket proxy that is compatible with OpenStack Nova.
Leverages websockify.py by Joel Martin
'''

import Cookie
import os
import socket
import sys

import websockify

from nova import context
from nova import flags
from nova.openstack.common import cfg
from nova.openstack.common import log as logging
from nova.openstack.common import rpc
from nova import utils


opts = [
    cfg.BoolOpt('record',
                default=False,
                help='Record sessions to FILE.[session_number]'),
    cfg.BoolOpt('daemon',
                default=False,
                help='Become a daemon (background process)'),
    cfg.BoolOpt('ssl_only',
                default=False,
                help='Disallow non-encrypted connections'),
    cfg.BoolOpt('source_is_ipv6',
                default=False,
                help='Source is ipv6'),
    cfg.StrOpt('cert',
               default='self.pem',
               help='SSL certificate file'),
    cfg.StrOpt('key',
               default=None,
               help='SSL key file (if separate from cert)'),
    cfg.StrOpt('web',
               default='/usr/share/novnc',
               help='Run webserver on same port. Serve files from DIR.'),
    cfg.StrOpt('novncproxy_host',
               default='0.0.0.0',
               help='Host on which to listen for incoming requests'),
    cfg.IntOpt('novncproxy_port',
               default=6080,
               help='Port on which to listen for incoming requests'),
    ]
FLAGS = flags.FLAGS
FLAGS.register_cli_opts(opts)
LOG = logging.getLogger(__name__)


class NovaWebSocketProxy(websockify.WebSocketProxy):
    def __init__(self, *args, **kwargs):
        websockify.WebSocketProxy.__init__(self, unix_target=None,
                                           target_cfg=None,
                                           ssl_target=None, *args, **kwargs)

    def new_client(self):
        """
        Called after a new WebSocket connection has been established.
        """
        cookie = Cookie.SimpleCookie()
        cookie.load(self.headers.getheader('cookie'))
        token = cookie['token'].value
        ctxt = context.get_admin_context()
        connect_info = rpc.call(ctxt, 'consoleauth',
                                {'method': 'check_token',
                                 'args': {'token': token}})

        if not connect_info:
            LOG.audit("Invalid Token: %s", token)
            raise Exception("Invalid Token")

        host = connect_info['host']
        port = int(connect_info['port'])

        # Connect to the target
        self.msg("connecting to: %s:%s" % (host, port))
        LOG.audit("connecting to: %s:%s" % (host, port))
        tsock = self.socket(host, port, connect=True)

        # Handshake as necessary
        if connect_info.get('internal_access_path'):
            tsock.send("CONNECT %s HTTP/1.1\r\n\r\n" %
                        connect_info['internal_access_path'])
            while True:
                data = tsock.recv(4096, socket.MSG_PEEK)
                if data.find("\r\n\r\n") != -1:
                    if not data.split("\r\n")[0].find("200"):
                        LOG.audit("Invalid Connection Info %s", token)
                        raise Exception("Invalid Connection Info")
                    tsock.recv(len(data))
                    break

        if self.verbose and not self.daemon:
            print(self.traffic_legend)

        # Start proxying
        try:
            self.do_proxy(tsock)
        except Exception:
            if tsock:
                tsock.shutdown(socket.SHUT_RDWR)
                tsock.close()
                self.vmsg("%s:%s: Target closed" % (host, port))
                LOG.audit("%s:%s: Target closed" % (host, port))
            raise


if __name__ == '__main__':
    if FLAGS.ssl_only and not os.path.exists(FLAGS.cert):
        parser.error("SSL only and %s not found" % FLAGS.cert)

    # Setup flags
    flags.parse_args(sys.argv)

    # Check to see if novnc html/js/css files are present
    if not os.path.exists(FLAGS.web):
        print "Can not find novnc html/js/css files at %s." % FLAGS.web
        sys.exit(-1)

    # Create and start the NovaWebSockets proxy
    server = NovaWebSocketProxy(listen_host=FLAGS.novncproxy_host,
                                listen_port=FLAGS.novncproxy_port,
                                source_is_ipv6=FLAGS.source_is_ipv6,
                                verbose=FLAGS.verbose,
                                cert=FLAGS.cert,
                                key=FLAGS.key,
                                ssl_only=FLAGS.ssl_only,
                                daemon=FLAGS.daemon,
                                record=FLAGS.record,
                                web=FLAGS.web,
                                target_host='ignore',
                                target_port='ignore',
                                wrap_mode='exit',
                                wrap_cmd=None)
    server.start_server()