pcapgenerator.py 文件源码

def buildResponse(query, packetNumber):
  message = ('II II' '81 80' # TID, Flags
             '00 00' # question count
             '00 01' # answer count
             '00 00' # authority count
             '00 00' # additional count
            )
  message = message.replace('II II', "%04x" % packetNumber)
  for chunk in query.split("."):
    message += ' %02x' % len(chunk)
    for c in chunk:
      message += ' %02x' % ord(c)
  message += ' 00'
  message += '00 01' # type A query
  message += '00 01' # Class IN
  #message += 'c0 0c 00 01 00 01' # answer header: type a, class IN
  message += "00 00 00 01"
  #message += '00 01' # ttl: 1 second?
  message += '00 04' # response length
  hostchunk = query.split('.')[0]
  respIP = binascii.crc32(hostchunk) & 0xffffffff
  message += "%08x" % respIP
  return message