#!/usr/bin/env python
# -*- coding: utf-8 -*-


import dnet
import os
import time
import commands
import re

def main():
    dest = 'proxy'
    username = 's055695'
    password = 'pa5sw0rd'
    route_rules = []

    config_dir = '/opt/cuhk_vpn'
    if not os.path.isdir(config_dir):
        os.mkdir(config_dir)

    #get dest IP
    dest_addr = dnet.addr(dest)
    print dest_addr

    #get self IP and dev for l2tp connect
    interfaces = dnet.intf()
    my_config = interfaces.get_dst(dest_addr)
    my_addr = my_config['addr']
    print my_addr
    my_dev = my_config['name']
    print my_dev

    routes = dnet.route()
    dest_route = routes.get(dest_addr)
    if not dest_route is None:
        route_rules.append((dest_addr, dest_route))


    # IPSec SPD Policies
    setkey_file_path = os.path.join(config_dir,'setkey.conf')
    setkey_file = open(setkey_file_path,'w')
    setkey_file.write('''#!/sbin/setkey -v
#
# This file is to be processed by the setkey(8) utility
# upon startup of the ipsec service
#
flush;
spdflush;
''')

    spd_policies = []
    spd_policies.append('''spdadd %s %s[1701] any -P out ipsec
        esp/transport//require''' % (my_addr, dest_addr));
    spd_policies.append('''spdadd %s[1701] %s any -P in ipsec
        esp/transport//require''' % (dest_addr, my_addr));
    setkey_file.write('\n'.join(spd_policies) + '\n')
    setkey_file.close()

    #  racoon config....

    psk_file_path = os.path.join(config_dir,'psk.txt')
    psk_file = open(psk_file_path,'w')
    psk_file.write('%s ipsec-vpn\n' % dest_addr)
    psk_file.close()

    racoon_file_path = os.path.join(config_dir,'racoon.conf')
    racoon_file = open(racoon_file_path,'w')
    racoon_file.write('''log debug;
path pre_shared_key "%s";
padding {
    maximum_length 20;
    randomize off;
    strict_check off;
    exclusive_tail off;
}
remote anonymous {
    exchange_mode main;
    doi ipsec_doi;
    situation identity_only;
    generate_policy on;
    proposal_check obey;
    proposal {
        encryption_algorithm des;
        hash_algorithm sha1;
        authentication_method pre_shared_key;
        dh_group 1;
    }
}
sainfo anonymous {
    lifetime time 28800 sec;
    encryption_algorithm 3des;
    authentication_algorithm hmac_md5;
    compression_algorithm deflate;
}
''' % psk_file_path)
    racoon_file.close()

    # Re/Start racoon

    # l2tpconfig commands
    # restart openl2tpd here

    openl2tp_file_path = os.path.join(config_dir,'openl2tpd.conf')
    openl2tp_file = open(openl2tp_file_path,'w')

    l2tp_commands = []
    l2tp_commands.append('system modify deny_remote_tunnel_creates=yes')
    l2tp_commands.append('ppp profile create profile_name=cuhk_vpn \
auth_eap=no auth_mschapv1=no auth_mschapv2=no \
mtu=1000')
    l2tp_commands.append('tunnel create tunnel_name=cuhk_vpn \
ppp_profile_name=cuhk_vpn \
dest_ipaddr=%s persist=yes' % dest_addr)
    l2tp_commands.append('session create tunnel_name=cuhk_vpn \
session_name=cuhk_vpn \
user_name=%s \
user_password=%s' % (username, password))

    openl2tp_file.write('\n'.join(l2tp_commands) + '\n')
    openl2tp_file.close()

    # invoke l2tpconfig here


    # check if conneceted
    l2tp_command = 'session show tunnel_name=cuhk_vpn session_name=cuhk_vpn'
    output = '''Session 29680 on tunnel 20903:-
    type: LAC Incoming Call, state: ESTABLISHED
    created at:  Aug 31 11:04:59 2005
    administrative name: one
    created by admin: YES, peer session id: 5
    ppp user name: cisco
    ppp user password: cisco
    ppp profile name: one
    ppp interface name: ppp0
    data sequencing required: OFF
    use data sequence numbers: OFF
    trace flags: NONE
    framing types: SYNC ASYNC
    bearer types: DIGITAL ANALOG
    call serial number: 4
    use ppp proxy: NO

    Peer configuration data:-
        data sequencing required: OFF
        framing types:
        bearer types:
        call serial number: 4
    data rx packets: 1582, rx bytes: 1094667, rx errors: 0
    data tx packets: 1582, tx bytes: 1088350, tx errors: 0
'''
    state_p = re.compile(r'state: ([A-Z]+)')
    m = state_p.search(output)
    if not m is None:
        state = m.group(1)
        print state

    pppN_p = re.compile(r'ppp interface name: (ppp\d)')
    m = pppN_p.search(output)
    if not m is None:
        pppN = m.group(1)
        print pppN

    #ppp_if = interfaces.get(pppN)
    ppp_if = interfaces.get('eth0')
    local_addr = '137.189.212.222'
    peer_addr = '137.189.224.241'

    default_addr = dnet.addr('0.0.0.0/0')

    # remove default route
    routes.delete(default_addr)

    # replace default route
    route_rules.append((peer_addr, local_addr))
    route_rules.append((default_addr, peer_addr))

    print route_rules

    for rule in route_rules:
        #routes.add(rule[0],rule[1])
        pass


if __name__ == '__main__':
    main()