#!/usr/bin/python

import sys,commands
from optparse import OptionParser
from dns.resolver import query
from dns.exception import DNSException
import re

# default domain list
config = '/etc/setroute.list'

# read domains from file
def read_list(file):

  lines = [line.strip() for line in open(config)]  
  names = []

  for name in lines:
    if name:
      names.append(name)
        
  return names

# host to IP addresses
def host_to_ip(name):
  ip = []
  try:
    qa = query(name,"A")
    for i in qa:  
      print name+"->"+i.to_text()
      ip.append(i.to_text())
  except DNSException:
    return []
  finally:
    return ip      

# convert names into IP addresses
def to_ip(names):
  re_ip = re.compile('\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}$')
  ip_list = []
  for name in names:
    if re_ip.match(name):
      ip_list = list(set(ip_list + [name]))
      print name+' appended'
    else:
      ip = host_to_ip(name)
      ip_list = list(set(ip_list + ip))
  return ip_list  

# set route
def set_route(list,interface,gateway,dest,remove):
  for i in list:
    if remove:
      if interface:
        if gateway:
          command = "route del -net %s netmask 255.255.255.255 gw %s dev %s" % (i,gateway,interface)
        else:
          command = "route del -net %s netmask 255.255.255.255 dev %s" % (i,interface)
      elif dest:  
        command = "iptables -t nat -D OUTPUT -p tcp -d %s -m tcp -j DNAT --to-destination %s" % (i,dest)
      elif gateway:  
        command = "route del -net %s netmask 255.255.255.255 gw %s" % (i,gateway)
      elif ipset:
        command = "ipset del %s %s" %(ipset,i)  
      print command
      commands.getoutput(command)
    else:  
      if interface:
        if gateway:
          command = "route add -net %s netmask 255.255.255.255 gw %s dev %s" % (i,gateway,interface)
        else:
          command = "route add -net %s netmask 255.255.255.255 dev %s" % (i,interface)
      elif dest:  
        command = "iptables -t nat -I OUTPUT -p tcp -d %s -m tcp -j DNAT --to-destination %s" % (i,dest)
      elif gateway:  
        command = "route add -net %s netmask 255.255.255.255 gw %s" % (i,gateway)
      elif ipset:
        command = "ipset add %s %s" %(ipset,i)  
      print command
      commands.getoutput(command)

# main procedure - process input parameters, read file and set route
def main():
  global dest,interface,gateway,remove
  try:
    domain_list = read_list(config)
  except:
    print "Cannot get domains list from file", config
    exit()  
  ip_list = to_ip(domain_list)
  set_route(ip_list,interface,gateway,dest,remove)

if __name__ == "__main__":
  parser = OptionParser()
  parser.add_option("-l", "--list", dest="config", help="Domain names list (default /etc/setroute.list) " )
  parser.add_option("-s", "--ipset", dest="ipset", help="IPset to fill in")
  parser.add_option("-d", "--destination", dest="destination", help="Proxy server (IP:Port)")
  parser.add_option("-i", "--interface", dest="interface", help="Interface name")
  parser.add_option("-g", "--gateway", dest="gateway", help="Gateway IP")
  parser.add_option("-r", "--remove", action="store_true", dest="remove", help="Remove redirection")
  (options, args) = parser.parse_args()
  opts = options.__dict__
  if opts["config"]:
    config = opts["config"]
  if opts["destination"]:
    dest = opts["destination"] 
  else:
    dest = None  
  if opts["interface"]:
    interface = opts["interface"] 
  else:
    interface = None  
  if opts["gateway"]:
    gateway = opts["gateway"] 
  else:
    gateway = None  
  if opts["remove"]:
    remove = opts["remove"] 
  else:
    remove = None  
  if opts["ipset"]:
    ipset = opts["ipset"] 
  else:
    ipset = None  
  main()