ether2any/tunnel/rfc1149/rfc1149.py

#!/usr/bin/python
# -*- coding: utf-8 -*-
#
# Copyright (C) 2011 Sebastian Lohff <seba@seba-geek.de>
# Licensed under GPL v3 or later

import pyudev
import subprocess
import scapy
from scapy.all import IP
import sys
import tempfile
import threading
from zlib import crc32

from conf import Conf

sys.path.append("../../../")

from ether2any import Ether2Any

class UdevReader(threading.Thread):
	def __init__(self, dev):
		threading.Thread.__init__(self)
		self.daemon = True
		self.context = pyudev.Context()

		self.dev = dev

		self.mountpoint = Conf.get("mountpoint")
		self.attrs = Conf.get("udevAttrs")
	
	def isUsableDevice(self, device):
		for k, v in self.attrs.items():
			try:
				if not device[k] == v:
					print device[k]
					return False
			except KeyError:
				return False
		return True

	def readPacket(self):
		print " ** Decoding packet"
		p = subprocess.Popen("find %s -iname '*jpg'  -printf '%%C@ %%p\n'|sort -n|tail -n 1|awk {'print $2'}" % (self.mountpoint,), shell=True, stdout=subprocess.PIPE)
		if p.wait() != 0:
			return False
		imgName = p.stdout.read().strip()
		if imgName == "":
			print " !! Error: No suitable image found"
			return False
		print "	++ Using image %s" % imgName
		print "	++ Attempting convert + tesseract decoding"
		imgFile, txtFile = tempfile.mktemp(suffix=".tif"), tempfile.mktemp()
		p = subprocess.Popen("convert %(input)s -colorspace Gray -white-threshold 45%% %(tmpImg)s ; tesseract %(tmpImg)s %(output)s nobatch tessconf/hex" % {'input': imgName, 'tmpImg': imgFile, 'output': txtFile}, shell=True)
		if p.wait() != 0:
			print "	!! Error executing convert/tesseract command"
			return False
		output = None
		try:
			outFile = open(txtFile + ".txt", "r")
			output = outFile.read()
			outFile.close()
		except IOError:
			print " !! Could not open tesseract output file"
			return False
		output = output.replace("\n", "").replace(" ", "")
		if len(output) % 2 != 0:
			print " !! Output of tesseract is not byte aligned"
			return False
		if len(output) < 10:
			print " !! Output of tesseract is not long enough"
			return False
		
		packet = "".join(map(lambda x: chr(int(output[x:x+2], 16)), xrange(0, len(output[0:-8]), 2)))
		checksum = int(output[-8:], 16)
		calcedChecksum = crc32(packet) & 0xffffffff
		if checksum != calcedChecksum:
			print " !! Checksum failed (was 0x%08x, should be 0x%08x)" % (checksum, calcedChecksum)
			return False
		self.dev.write(packet)
		return True
	
	def run(self):
		monitor = pyudev.Monitor.from_netlink(self.context)
		monitor.filter_by(subsystem='block')
		for action, device in monitor:
			if self.isUsableDevice(device):
				self.devname = device['DEVNAME']
				if action == 'add':
					print ["/bin/mount", self.devname, self.mountpoint]
					p = subprocess.Popen(["/bin/mount", self.devname, self.mountpoint])
					ret = p.wait()
					if ret == 0:
						print " ++ Mounted camera/card (%s) at %s" % (self.devname, self.mountpoint)
						if self.readPacket():
							print " >> Successfully read packet"
						else:
							print " !! Error reading packet"
						print " ** Releasing camera/card (%s)..." % (self.devname,)
						subprocess.Popen(["/bin/umount", "-f", self.devname])
						subprocess.Popen("/bin/sync")
						print " ** Unmounted"
					else:
						print " !! Error mounting stick (%s) at %s: Error id %d" % (self.devname, self.mountpoint, ret)
				elif action == 'remove':
					print " -- Camera/card (%s) removed." % self.devname


class RFC1149(Ether2Any):
	
	def __init__(self):
		Ether2Any.__init__(self, tap=False)
		
		network = Conf.get("network", {'mtu': 1500})
		
		self.dev.ifconfig(**network)
		self.dev.up()
		
		self.reader = UdevReader(self.dev)
		self.reader.start()
	
	def toPrinter(self, packet):
		packet = packet.upper()
		print packet
	
	def sendToNet(self, packet):
		print "packet", repr(packet)
		scp = IP(packet)
		checksum = crc32(packet) & 0xffffffff
		checksumStr = "%08x" % checksum
		hexRepr = " ".join(map(lambda x: "%02x" % ord(x), packet[4:])) + " " + " ".join(map(lambda x: checksumStr[x:x+2], range(0, len(checksumStr), 2)))
		print " ?>", scp.summary(), " -- hex len", len(hexRepr), "checksum 0x%08x" % checksum
		i = ""
		while i.lower() not in ("a", "d"):
			i = raw_input(" ?? (A)ccept/(D)rop? ")
		if i == "a":
			# accept the packet!
			print " >> Moved one packet to printer"
			self.toPrinter(hexRepr)
			self.reader.output(hexRepr.replace(" ", ""))
		else:
			print " -- Dropped"

if __name__ == '__main__':
	rfc1149 = RFC1149()
	rfc1149.run()