#!/usr/bin/python3

# Lifted from Russ Dill's juniper-vpn-wrap.py, thus:
#
#    This program is free software; you can redistribute it and/or modify
#    it under the terms of the GNU General Public License as published by
#    the Free Software Foundation; either version 2 of the License, or
#    (at your option) any later version.
#
#    This program is distributed in the hope that it will be useful,
#    but WITHOUT ANY WARRANTY; without even the implied warranty of
#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#    GNU General Public License for more details.
#
#    You should have received a copy of the GNU General Public License
#    along with this program; if not, write to the Free Software
#    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

import subprocess
import sys
import os
import zipfile
import urllib.request
import ssl

# In order to run this, you will need to build tncc_preload.so (from
# https://github.com/russdill/ncsvc-socks-wrapper) and place it in this
# directory.
#
# Very old versions of the TNCC Java binary expect to find files in
# ~/.juniper_networks instead of ~/.pulse_secure
TNCC_DIRECTORY = "~/.pulse_secure"

ssl._create_default_https_context = ssl._create_unverified_context


class Tncc:
    def __init__(self, vpn_host):
        self.vpn_host = vpn_host
        self.plugin_jar = '/usr/share/icedtea-web/plugin.jar'

        if not os.path.isfile(self.plugin_jar):
            print('WARNING: no IcedTea Java web plugin JAR found at %s' % self.plugin_jar, file=sys.stderr)
            self.plugin_jar = None
        self.user_agent = 'Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.0.1) Gecko/2008071615 Fedora/3.0.1-1.fc9 Firefox/3.0.1'

    def tncc_init(self):
        class_names = ('net.juniper.tnc.NARPlatform.linux.LinuxHttpNAR',
                       'net.juniper.tnc.HttpNAR.HttpNAR')
        self.class_name = None

        self.tncc_jar = os.path.expanduser(os.path.join(TNCC_DIRECTORY, 'tncc.jar'))
        try:
            if zipfile.ZipFile(self.tncc_jar, 'r').testzip() is not None:
                raise Exception()
        except Exception:
            print('Downloading tncc.jar...')
            os.makedirs(os.path.expanduser(TNCC_DIRECTORY), exist_ok=True)
            urllib.request.urlretrieve('https://' + self.vpn_host
                                       + '/dana-cached/hc/tncc.jar', self.tncc_jar)

        with zipfile.ZipFile(self.tncc_jar, 'r') as jar:
            for name in class_names:
                try:
                    jar.getinfo(name.replace('.', '/') + '.class')
                    self.class_name = name
                    break
                except Exception:
                    pass
            else:
                raise Exception('Could not find class name for', self.tncc_jar)

        self.tncc_preload = \
            os.path.expanduser(os.path.join(TNCC_DIRECTORY, 'tncc_preload.so'))
        if not os.path.isfile(self.tncc_preload):
            print('WARNING: no tncc_preload found at %s' % self.tncc_preload, file=sys.stderr)
            self.tncc_preload = None

    def tncc_start(self):
        # tncc is the host checker app. It can check different
        # security policies of the host and report back. We have
        # to send it a preauth key (from the DSPREAUTH cookie)
        # and it sends back a new cookie value we submit.
        # After logging in, we send back another cookie to tncc.
        # Subsequently, it contacts https://<vpn_host:443 every
        # 10 minutes.

        if not self.tncc_jar:
            self.tncc_init()

        self.tncc_process = subprocess.Popen(['java',
            '-classpath', self.tncc_jar + (':' + self.plugin_jar if self.plugin_jar else ''),
            self.class_name,
            'log_level', '100',
            'postRetries', '6',
            'ivehost', self.vpn_host,
            'home_dir', os.path.expanduser('~'),
            'Parameter0', '',
            'user_agent', self.user_agent,
            ], env={'LD_PRELOAD': self.tncc_preload} if self.tncc_preload else {})


if __name__ == "__main__":
    if len(sys.argv) <= 1:
        print("Usage: %s [vpn-host]" % sys.argv[0])
        raise SystemExit(1)

    tncc = Tncc(sys.argv[1])
    tncc.tncc_init()
    tncc.tncc_start()