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@scturtle
Last active Dec 22, 2015
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dns proxy server using 0bad.com and ip
import SocketServer
from gevent import monkey
monkey.patch_socket(dns=False)
import requests
from dnslib import *
cache = {'0bad.com': ['69.163.160.212'], 'bitstress.com': ['127.0.0.1']}
def redirect_ip(data, ip='144.214.121.220'):
s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
# query the official server
s.sendto(data, (ip, 53))
data, server = s.recvfrom(2048)
s.close()
# parse reply
#reply = DNSRecord.parse(data)
#ips = [str(rr.rdata) for rr in reply.rr]
#print 'from school'#, ip, ips
return data
def redirect_tcp(data, ip='8.8.8.8'):
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.settimeout(10)
s.connect((ip, 53))
s.sendall(data)
data = s.recv(2048)
s.close()
return data
def redirect_0bad(data, request):
id, qname, qtype = request.header.id, request.q.qname, request.q.qtype
domain = str(qname)
# if relate to school, redirect to the official server
if domain.endswith('.edu.hk'):
return redirect_ip(data)
# construct reply
reply = DNSRecord(DNSHeader(id=id, qr=1, aa=1, ra=1), q=request.q)
# fix
data = redirect_ip(data)
reply = DNSRecord.parse(data)
for r in reply.rr:
if r.rtype != QTYPE.A:
reply.add_answer(r)
if qtype == QTYPE.A:
# query the 0bad.com
if domain not in cache:
text = requests.get('http://0bad.com/?dm='+domain).text
text = text.strip().replace('<pre>', '').replace('</pre>', '')
lines = [l.split() for l in text.split('\n') if l]
lines = [l for l in lines if l[-2] == 'A']
ips = [l[-1] for l in lines]
cache[domain] = ips
else:
ips = cache[domain]
print ips
for ip in ips:
reply.add_answer(RR(qname, qtype, rdata=A(ip)))
return reply.pack()
else:
# else, query the official server
return redirect_ip(data)
class ServerHandler(SocketServer.BaseRequestHandler):
daemon_threads = True
allow_reuse_address = True
def handle(self):
data = self.request[0]
socket = self.request[1]
addr = self.client_address
request = DNSRecord.parse(data)
qname, qtype = request.q.qname, request.q.qtype
print '\nrequest: {} {}'.format(str(qname), QTYPE[qtype])
#data = redirect_ip(data)
#data = redirect_tcp(data)
data = redirect_0bad(data, request)
socket.sendto(data, addr)
class ThreadedUDPServer(SocketServer.ThreadingMixIn, SocketServer.UDPServer):
def __init__(self, s, t):
SocketServer.UDPServer.__init__(self, s, t)
def main():
try:
server = ThreadedUDPServer(('127.0.0.1', 53), ServerHandler)
except Exception as e:
print "Failed to create socket on UDP port 53:", e
exit(1)
print 'start listening on 53 ...'
server.serve_forever()
server.shutdown()
if __name__ == '__main__':
main()
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