#!/usr/bin/python
from scapy.all import *
from subprocess import Popen, PIPE
import os,sys


class Proxy:
	srcIP = ""
	dstIP = ""
	srcPort = ""
	dstPort = ""
	seq = None
	ack = None

	def __init__(self, data):
		self.index = data

	def main(self):
		#First add iptables rules
		self.iptables("-A")
		print "IPTABLES rules updated"

		#Listen for SYN to port 80
		sniff(filter="tcp dst port 80 && tcp[13] & 2 != 0", prn=self.procSyn)
		self.flush()
		print "Removed IPTABLES Rules"

	def procSyn(self, syn):
		self.srcIP = syn[IP].src
		self.dstIP = syn[IP].dst
		self.srcPort = syn[TCP].sport
		self.dstPort = syn[TCP].dport

		iplayer = IP(src=self.dstIP, dst=self.srcIP)

		print "Received SYN from %s" % str(self.srcIP)
	
		#SYN Packet
		self.seq = 9001
		p = iplayer/TCP(seq=self.seq, sport=self.dstPort, dport=self.srcPort, flags="S")
		print "Sending SYN..."
		#SYN ACK
		synack = sr1(p, timeout=1)

		if not synack:
			print "SYN-ACK not received"
			return 0
			#self.flush()
			#sys.exit(1)

		print "Received SYN-ACK"
		#ACK
		self.seq = self.seq + 1
		self.ack = synack.seq + 1

		print "Sending ACK..."
		p = iplayer/TCP(seq=self.seq, ack = self.ack, sport=self.dstPort, dport=self.srcPort, flags="A")

		#HTTP GET
		get = sr1(p, timeout=1)

		if not get:
			print "GET not received"
			return 0
			#self.flush()
			#sys.exit(1)

		print "Got data packet"

		data_len = len(get[Raw])

		payload = "HTTP/1.1 200 OK\r\nDate: Mon, 08 Mar 2010 03:17:15 CMD\r\nServer: \r\nContent-Length: %s\r\nKeep-Alive: timeout=5, max=99\r\nConnection: Keep-Alive\r\nContent-Type: text/html; charset=utf-8\r\n\r\n%s" % (str(len(self.index)), self.index)

		self.seq = get.ack
		self.ack = get.seq + data_len

		p = iplayer/TCP(seq=self.seq, ack=self.ack, sport=self.dstPort, dport=self.srcPort, flags="A")
		send(p)

		#HTTP Reseponse
		p = iplayer/TCP(seq=self.seq, ack=self.ack, sport=self.dstPort, dport=self.srcPort, flags="A")/payload

		send(p)

	def iptables(self, action):
		cmd  = "iptables %s OUTPUT -p tcp --tcp-flags RST RST -j DROP" % action
		cmd2 = "iptables %s OUTPUT -p ICMP --icmp-type port-unreachable -j DROP" % action

		p = Popen(cmd, stdout=PIPE, stderr=PIPE, shell=True)
		p.wait()
		p2 = Popen(cmd2, stdout=PIPE, stderr=PIPE, shell=True)
		p2.wait()

	def flush(self):
		cmd = "iptables -F OUTPUT"
		p = Popen(cmd, stdout=PIPE, stderr=PIPE, shell=True)
		p.wait()

if __name__ == "__main__":
	index = sys.argv[1]
	f = open(index,'rb')
	data = f.read()
	f.close()
	
	p = Proxy(data)
	p.main()