pcap.py

import struct
import time

PCAP_GLOBAL_HEADER_FMT = '@ I H H i I I I '


# Global Header Values
PCAP_MAGICAL_NUMBER = 2712847316
PCAP_MJ_VERN_NUMBER = 2
PCAP_MI_VERN_NUMBER = 4
PCAP_LOCAL_CORECTIN = 0
PCAP_ACCUR_TIMSTAMP = 0
PCAP_MAX_LENGTH_CAP = 65535
PCAP_DATA_LINK_TYPE = 1

class Pcap:
    

 def __init__(self, filename, link_type=PCAP_DATA_LINK_TYPE):
  self.pcap_file = open(filename, 'wb') # 4 + 2 + 2 + 4 + 4 + 4 + 4
  self.pcap_file.write(struct.pack('@ I H H i I I I ', PCAP_MAGICAL_NUMBER, PCAP_MJ_VERN_NUMBER, PCAP_MI_VERN_NUMBER, PCAP_LOCAL_CORECTIN, PCAP_ACCUR_TIMSTAMP, PCAP_MAX_LENGTH_CAP, link_type))
  print ("[+] Link Type : {}".format(link_type))

 def writelist(self, data=[]):
  for i in data:
   self.write(i)
  return

 def write(self, data):
  ts_sec, ts_usec = map(int, str(time.time()).split('.'))
  length = len(data)
  self.pcap_file.write(struct.pack('@ I I I I', ts_sec, ts_usec, length, length))
  self.pcap_file.write(data)