Generate route files for openvpn in openwrt

chnroutes_openwrt.py

#!/usr/bin/env python

"""
hacked for openwrt, from http://chnroutes.googlecode.com/files/chnroutes.py
"""

import re
import urllib2
import sys
import argparse
import math

def generate_openwrt():
    results = fetch_ip_data()
    upscript_header = """#!/bin/sh
export PATH="/bin:/sbin:/usr/sbin:/usr/bin"

OLDGW=`route -n|grep '^0\.0\.0\.0.*pppoe-wan$'|tr -s ' '|cut -d ' ' -f2`

if [ $OLDGW == '' ]; then
    exit 0
fi

if [ ! -e /tmp/vpn_oldgw ]; then
    echo $OLDGW > /tmp/vpn_oldgw
fi

    """

    downscript_header = """#!/bin/sh
export PATH="/bin:/sbin:/usr/sbin:/usr/bin"

OLDGW=`cat /tmp/vpn_oldgw`

    """

    upfile = open('vpnup','w')
    downfile = open('vpndown','w')
    upfile.write(upscript_header)
    upfile.write('\n')
    downfile.write(downscript_header)
    downfile.write('\n')

    for ip, mask, _ in results:
        upfile.write('route add -net %s netmask %s gw $OLDGW\n'%(ip,mask))
        downfile.write('route del -net %s netmask %s\n'%(ip,mask))

    downfile.write('rm /tmp/vpn_oldgw\n')

    print """Route files are generated.

Login to your openwrt, then copy vpnup to /etc/openvpn/vpnup, and copy vpndown to /etc/openvpn/vpndown.

Append following scripts into your openvpn.conf:

    script-security 2
    up /etc/openvpn/vpnup
    down /etc/openvpn/vpndown
    """

def fetch_ip_data():
    #fetch data from apnic
    print "Fetching data from apnic.net, it might take a few minutes, please wait..."
    url=r'http://ftp.apnic.net/apnic/stats/apnic/delegated-apnic-latest'
    data=urllib2.urlopen(url).read()

    cnregex=re.compile(r'apnic\|cn\|ipv4\|[0-9\.]+\|[0-9]+\|[0-9]+\|a.*',re.IGNORECASE)
    cndata=cnregex.findall(data)

    results=[]

    for item in cndata:
        unit_items=item.split('|')
        starting_ip=unit_items[3]
        num_ip=int(unit_items[4])

        imask=0xffffffff^(num_ip-1)
        #convert to string
        imask=hex(imask)[2:]
        mask=[0]*4
        mask[0]=imask[0:2]
        mask[1]=imask[2:4]
        mask[2]=imask[4:6]
        mask[3]=imask[6:8]

        #convert str to int
        mask=[ int(i,16 ) for i in mask]
        mask="%d.%d.%d.%d"%tuple(mask)

        #mask in *nix format
        mask2=32-int(math.log(num_ip,2))

        results.append((starting_ip,mask,mask2))

    return results

def main():
    if len(sys.argv) > 1 and sys.argv[1] in ("-h", "--help"):
        print "Run this script directly to generate route files for openvpn of openwrt."
        sys.exit(1)
    generate_openwrt()

if __name__=='__main__':
    main()