path: root/src/leap/OpenVPNConnection.py

"""
OpenVPN Connection
"""

from __future__ import (print_function)
import logging
import os
import socket
import telnetlib
import time
from functools import partial

logger = logging.getLogger(name=__name__)

from leap.utils.coroutines import spawn_and_watch_process
from leap.baseapp.config import get_config
from leap.Connection import Connection

class OpenVPNConnection(Connection):
    """
    All related to invocation
    of the openvpn binary
    """
    # Connection Methods

    def __init__(self, config_file=None, watcher_cb=None,host="/tmp/.eip.sock", port="unix", password=None):
        #XXX FIXME
        #change watcher_cb to line_observer
        """
        :param config_file: configuration file to read from
        :param watcher_cb: callback to be \
called for each line in watched stdout
        :param signal_map: dictionary of signal names and callables \
to be triggered for each one of them.
        :type config_file: str
        :type watcher_cb: function
        :type signal_map: dict
        """

        self.config_file = config_file
        self.watcher_cb = watcher_cb
        #self.signal_maps = signal_maps

        self.subp = None
        self.watcher = None

        self.server = None
        self.port = None
        self.proto = None

        self.autostart = True

        self._get_config()

        #Get this info from the Configuration Class
        #XXX hardcoded host here. change.
        self.host = host
        if isinstance(port, str) and port.isdigit():
            port = int(port)
        self.port = port
        self.password = password
        self.tn = None

        #XXX workaround for signaling
        #the ui that we don't know how to
        #manage a connection error
        self.with_errors = False


    def _set_command_mockup(self):
        """
        sets command and args for a command mockup
        that just mimics the output from the real thing
        """
        command, args = get_vpn_stdout_mockup()
        self.command, self.args = command, args

    def _get_config(self):
        """
        retrieves the config options from defaults or
        home file, or config file passed in command line.
        """
        config = get_config(config_file=self.config_file)
        self.config = config

        if config.has_option('openvpn', 'command'):
            commandline = config.get('openvpn', 'command')
            if commandline == "mockup":
                self._set_command_mockup()
                return
            command_split = commandline.split(' ')
            command = command_split[0]
            if len(command_split) > 1:
                args = command_split[1:]
            else:
                args = []
            self.command = command
            #print("debug: command = %s" % command)
            self.args = args
        else:
            self._set_command_mockup()

        if config.has_option('openvpn', 'autostart'):
            autostart = config.get('openvpn', 'autostart')
            self.autostart = autostart

    def _launch_openvpn(self):
        """
        invocation of openvpn binaries in a subprocess.
        """
        #XXX TODO:
        #deprecate watcher_cb,
        #use _only_ signal_maps instead

        if self.watcher_cb is not None:
            linewrite_callback = self.watcher_cb
        else:
            #XXX get logger instead
            linewrite_callback = lambda line: print('watcher: %s' % line)

        observers = (linewrite_callback,
                     partial(self.status_watcher, self.status))
        subp, watcher = spawn_and_watch_process(
            self.command,
            self.args,
            observers=observers)
        self.subp = subp
        self.watcher = watcher

        conn_result = self.status.CONNECTED
        return conn_result

    def _try_connection(self):
        """
        attempts to connect
        """
        if self.subp is not None:
            print('cowardly refusing to launch subprocess again')
            return
        self._launch_openvpn()

    def cleanup(self):
        """
        terminates child subprocess
        """
        if self.subp:
            self.subp.terminate()


    #Here are the actual code to manage OpenVPN Connection
    #TODO: Look into abstraction them and moving them up into base class 
    # this code based on code from cube-routed project

    """
    Run commands over OpenVPN management interface
    and parses the output.
    """
    # XXX might need a lock to avoid
    # race conditions here...

    def forget_errors(self):
        print('forgetting errors')
        self.with_errors = False

    def connect(self):
        """Connect to openvpn management interface"""
        try:
            self.close()
        except:
            #XXX don't like this general
            #catch here.
            pass
        if self.connected():
            return True
        self.tn = UDSTelnet(self.host, self.port)

        # XXX make password optional
        # specially for win plat. we should generate
        # the pass on the fly when invoking manager
        # from conductor

        #self.tn.read_until('ENTER PASSWORD:', 2)
        #self.tn.write(self.password + '\n')
        #self.tn.read_until('SUCCESS:', 2)

        self._seek_to_eof()
        self.forget_errors()
        return True

    def _seek_to_eof(self):
        """
        Read as much as available. Position seek pointer to end of stream
        """
        b = self.tn.read_eager()
        while b:
            b = self.tn.read_eager()

    def connected(self):
        """
        Returns True if connected
        rtype: bool
        """
        #return bool(getattr(self, 'tn', None))
        try:
            assert self.tn
            return True
        except:
            #XXX get rid of
            #this pokemon exception!!!
            return False

    def close(self, announce=True):
        """
        Close connection to openvpn management interface
        """
        if announce:
            self.tn.write("quit\n")
            self.tn.read_all()
        self.tn.get_socket().close()
        del self.tn

    def _send_command(self, cmd, tries=0):
        """
        Send a command to openvpn and return response as list
        """
        if tries > 3:
            return []
        if not self.connected():
            try:
                self.connect()
            except MissingSocketError:
                #XXX capture more helpful error
                #messages
                #pass
                return self.make_error()
        try:
            self.tn.write(cmd + "\n")
        except socket.error:
            logger.error('socket error')
            print('socket error!')
            self.close(announce=False)
            self._send_command(cmd, tries=tries + 1)
            return []
        buf = self.tn.read_until(b"END", 2)
        self._seek_to_eof()
        blist = buf.split('\r\n')
        if blist[-1].startswith('END'):
            del blist[-1]
            return blist
        else:
            return []

    def _send_short_command(self, cmd):
        """
        parse output from commands that are
        delimited by "success" instead
        """
        if not self.connected():
            self.connect()
        self.tn.write(cmd + "\n")
        # XXX not working?
        buf = self.tn.read_until(b"SUCCESS", 2)
        self._seek_to_eof()
        blist = buf.split('\r\n')
        return blist

    #
    # useful vpn commands
    #

    def pid(self):
        #XXX broken
        return self._send_short_command("pid")

    def make_error(self):
        """
        capture error and wrap it in an
        understandable format
        """
        #XXX get helpful error codes
        self.with_errors = True
        now = int(time.time())
        return '%s,LAUNCHER ERROR,ERROR,-,-' % now

    def state(self):
        """
        OpenVPN command: state
        """
        state = self._send_command("state")
        if not state:
            return None
        if isinstance(state, str):
            return state
        if isinstance(state, list):
            if len(state) == 1:
                return state[0]
            else:
                return state[-1]

    def status(self):
        """
        OpenVPN command: status
        """
        status = self._send_command("status")
        return status

    def status2(self):
        """
        OpenVPN command: last 2 statuses
        """
        return self._send_command("status 2")

    #
    # parse  info
    #

    def get_status_io(self):
        status = self.status()
        if isinstance(status, str):
            lines = status.split('\n')
        if isinstance(status, list):
            lines = status
        try:
            (header, when, tun_read, tun_write,
             tcp_read, tcp_write, auth_read) = tuple(lines)
        except ValueError:
            return None

        when_ts = time.strptime(when.split(',')[1], "%a %b %d %H:%M:%S %Y")
        sep = ','
        # XXX cleanup!
        tun_read = tun_read.split(sep)[1]
        tun_write = tun_write.split(sep)[1]
        tcp_read = tcp_read.split(sep)[1]
        tcp_write = tcp_write.split(sep)[1]
        auth_read = auth_read.split(sep)[1]

        # XXX this could be a named tuple. prettier.
        return when_ts, (tun_read, tun_write, tcp_read, tcp_write, auth_read)

    def get_connection_state(self):
        state = self.state()
        if state is not None:
            ts, status_step, ok, ip, remote = state.split(',')
            ts = time.gmtime(float(ts))
            # XXX this could be a named tuple. prettier.
            return ts, status_step, ok, ip, remote

    def status_watcher(self, cs, line):
        """
        a wrapper that calls to ConnectionStatus object
        :param cs: a EIPConnectionStatus instance
        :type cs: EIPConnectionStatus object
        :param line: a single line of the watched output
        :type line: str
        """
        #print('status watcher watching')

        # from the mullvad code, should watch for
        # things like:
        # "Initialization Sequence Completed"
        # "With Errors"
        # "Tap-Win32"

        if "Completed" in line:
            cs.change_to(cs.CONNECTED)
            return

        if "Initial packet from" in line:
            cs.change_to(cs.CONNECTING)
            return



class MissingSocketError(Exception):
    pass


class ConnectionRefusedError(Exception):
    pass

class UDSTelnet(telnetlib.Telnet):

    def open(self, host, port=23, timeout=socket._GLOBAL_DEFAULT_TIMEOUT):
        """Connect to a host. If port is 'unix', it
        will open a connection over unix docmain sockets.

        The optional second argument is the port number, which
        defaults to the standard telnet port (23).

        Don't try to reopen an already connected instance.
        """
        self.eof = 0
        self.host = host
        self.port = port
        self.timeout = timeout

        if self.port == "unix":
            # unix sockets spoken
            if not os.path.exists(self.host):
                raise MissingSocketError
            self.sock = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
            try:
                self.sock.connect(self.host)
            except socket.error:
                raise ConnectionRefusedError
        else:
            self.sock = socket.create_connection((host, port), timeout)