BOSWatch/includes/decoders/fms.py

#!/usr/bin/python
# -*- coding: cp1252 -*-

"""
FMS Decoder

@author: Bastian Schroll

@requires: Configuration has to be set in the config.ini
"""

import logging
import time #timestamp for doublealarm
import re #Regex for validation

from includes import globals  # Global variables

#FMS Decoder Function
#validate -> check double alarm -> log      
def decode(freq, decoded):
	"""
	Export FMS Information from Multimon-NG RAW String and call alarmHandler.processAlarm()

	@type    freq: string
	@param   freq: frequency of the SDR Stick
	@type    decoded: string
	@param   decoded: RAW Information from Multimon-NG

	@requires:  Configuration has to be set in the config.ini
	
	@return:    nothing
	@exception: Exception if FMS decode failed
	"""
	timestamp = int(time.time())#Get Timestamp                  

	fms_service = decoded[19]       #Organisation
	fms_country = decoded[36]       #Bundesland
	fms_location = decoded[65:67]   #Ort
	fms_vehicle = decoded[72:76]    #Fahrzeug
	fms_status = decoded[84]        #Status
	fms_direction = decoded[101]    #Richtung
	fms_tsi = decoded[114:117]      #Taktische Kruzinformation
		
	if "CRC correct" in decoded: #check CRC is correct  
		fms_id = fms_service+fms_country+fms_location+fms_vehicle+fms_status+fms_direction #build FMS id
		if re.search("[0-9a-f]{8}[0-9a-f]{1}[01]{1}", fms_id): #if FMS is valid
			if fms_id == globals.fms_id_old and timestamp < globals.fms_time_old + globals.config.getint("FMS", "double_ignore_time"): #check for double alarm
				logging.info("FMS double alarm: %s within %s second(s)", globals.fms_id_old, timestamp-globals.fms_time_old)
				globals.fms_time_old = timestamp #in case of double alarm, fms_double_ignore_time set new
			else:
				logging.info("FMS:%s Status:%s Richtung:%s TSI:%s", fms_id[0:8], fms_status, fms_direction, fms_tsi)
				data = {"fms":fms_id[0:8], "status":fms_status, "direction":fms_direction, "tsi":fms_tsi}
				from includes import alarmHandler
				alarmHandler.processAlarm("FMS",freq,data)
				
				globals.fms_id_old = fms_id #save last id
				globals.fms_time_old = timestamp #save last time	
		else:
			logging.warning("No valid FMS: %s", fms_id)    
	else:
		logging.warning("FMS CRC incorrect")