--- /dev/null
+#!/usr/bin/python
+
+"""
+Script that takes a file (output by wireshark/tshark, in JSON format) and analyze
+the variety of packet sizes of a certain device at a certain time.
+"""
+
+import sys
+import json
+import numpy as np
+from collections import defaultdict
+from dateutil import parser
+
+JSON_KEY_SOURCE = "_source"
+JSON_KEY_LAYERS = "layers"
+
+JSON_KEY_ETH = "eth"
+JSON_KEY_ETH_DST = "eth.dst"
+JSON_KEY_ETH_SRC = "eth.src"
+JSON_KEY_FRAME = "frame"
+JSON_KEY_FRAME_TIME = "frame.time"
+JSON_KEY_FRAME_LENGTH = "frame.len"
+TABLE_HEADER_X = "Timestamp (hh:mm:ss)"
+TABLE_HEADER_Y = "Packet sizes (bytes)"
+INCOMING_APPENDIX = "_incoming"
+OUTGOING_APPENDIX = "_outgoing"
+FILE_APPENDIX = ".dat"
+
+
+def save_to_file(tblheader, dictionary, filenameout):
+ """ Show summary of statistics of PCAP file
+ Args:
+ tblheader: header for the saved table
+ dictionary: dictionary to be saved
+ filename_out: file name to save
+ """
+ # Appending, not overwriting!
+ f = open(filenameout, 'a')
+ # Write the table header
+ f.write("# " + tblheader + "\n")
+ f.write("# " + TABLE_HEADER_X + " " + TABLE_HEADER_Y + "\n")
+ # Write "0 0" if dictionary is empty
+ if not dictionary:
+ f.write("0 0")
+ f.close()
+ print "Writing zeroes to file: ", filenameout
+ return
+
+ # Iterate over dictionary and write (key, value) pairs
+ for key in sorted(dictionary):
+ # Space separated
+ f.write(str(key) + " " + str(dictionary[key]) + "\n")
+ f.close()
+ print "Writing output to file: ", filenameout
+
+
+def main():
+ """ Main function
+ """
+ if len(sys.argv) < 5:
+ print "Usage: python", sys.argv[0], "<input_file> <output_file> <device_name> <mac_address>"
+ return
+ # Parse the file for the specified MAC address
+ timefreq_incoming = parse_json(sys.argv[1], sys.argv[4], True)
+ timefreq_outgoing = parse_json(sys.argv[1], sys.argv[4], False)
+ # Write statistics into file
+ print "====================================================================="
+ print "==> Analyzing incoming traffic ..."
+ save_to_file(sys.argv[3] + INCOMING_APPENDIX, timefreq_incoming, sys.argv[2] + INCOMING_APPENDIX + FILE_APPENDIX)
+ print "====================================================================="
+ print "==> Analyzing outgoing traffic ..."
+ save_to_file(sys.argv[3] + OUTGOING_APPENDIX, timefreq_outgoing, sys.argv[2] + OUTGOING_APPENDIX + FILE_APPENDIX)
+ print "====================================================================="
+
+
+# Convert JSON file containing DNS traffic to a map in which a hostname points to its set of associated IPs.
+def parse_json(filepath, macaddress, incomingoutgoing):
+ """ Show summary of statistics of PCAP file
+ Args:
+ filepath: path of the read file
+ macaddress: MAC address of a device to analyze
+ incomingoutgoing: boolean to define whether we collect incoming or outgoing traffic
+ True = incoming, False = outgoing
+ """
+ # Maps timestamps to frequencies of packets
+ packetsize = dict()
+ with open(filepath) as jf:
+ # Read JSON.
+ # data becomes reference to root JSON object (or in our case json array)
+ data = json.load(jf)
+ # Loop through json objects in data
+ # Each entry is a pcap entry (request/response (packet) and associated metadata)
+ for p in data:
+ # p is a JSON object, not an index
+ layers = p[JSON_KEY_SOURCE][JSON_KEY_LAYERS]
+ # Get timestamp
+ frame = layers.get(JSON_KEY_FRAME, None)
+ datetime = frame.get(JSON_KEY_FRAME_TIME, None)
+ length = frame.get(JSON_KEY_FRAME_LENGTH, None)
+ # Get into the Ethernet address part
+ eth = layers.get(JSON_KEY_ETH, None)
+ # Skip any non DNS traffic
+ if eth is None:
+ print "[ WARNING: Packet has no ethernet address! ]"
+ continue
+ # Get source and destination MAC addresses
+ src = eth.get(JSON_KEY_ETH_SRC, None)
+ dst = eth.get(JSON_KEY_ETH_DST, None)
+ # Get just the time part
+ datetimeobj = parser.parse(datetime)
+ timestr = str(datetimeobj.time())
+ print str(timestr) + " - src:" + str(src) + " - dest:" + str(dst)
+ # Get and count the traffic for the specified MAC address
+ if incomingoutgoing:
+ if dst == macaddress:
+ # Put the time frequency in the dictionary
+ packetsize[timestr] = length
+ else:
+ if src == macaddress:
+ # Put the time frequency in the dictionary
+ packetsize[timestr] = length
+
+ return packetsize
+
+
+if __name__ == '__main__':
+ main()
+