python 抓包保存为pcap文件并解析的实例

Z时代
2024-01-10
分类：综合

首先是抓包，使用scapy模块，

sniff()函数在其中参数为本地文件路径时，操作为打开本地文件

若参数为BPF过滤规则和回调函数，则进行Sniff，回调函数用于对Sniff到的数据包进行处理


import os
from scapy.all import *
pkts=[]
count=0
pcapnum=0
filename=''
def test_dump_file(dump_file):
  print "Testing the dump file..."
  if os.path.exists(dump_file):
    print "dump fie %s found." %dump_file
    pkts=sniff(offline=dump_file)
    count = 0
    while (count<=2):                   
      print "----Dumping pkt:%s----" %dump_file
      print hexdump(pkts[count])
      count +=1
  else:
    print "dump fie %s not found." %dump_file
def write_cap(x):
  global pkts
  global count
  global pcapnum
  global filename
  pkts.append(x)
  count +=1
  if count ==3:             <span style="font-family: Arial, Helvetica, sans-serif;">#每3个TCP操作封为一个包（为了检测正确性，使用时尽量增多）</span>
  pcapnum +=1
  pname="pcap%d.pcap"%pcapnum
  wrpcap(pname,pkts)
  filename ="./pcap%d.pcap"%pcapnum
  test_dump_file(filename)
  pkts=[]
  count=0
if __name__=='__main__':
  print "Start packet capturing and dumping ..."
  sniff(filter="dst net 127.0.0.1 and tcp",prn=write_cap)   #BPF过滤规则

下面是对pcap文件的解析，会自动查找下一个pcap文件，按照src.ip和dst.ip进行划分


# -*- coding: cp936 -*-
import re
import zlib
import os
from scapy.all import *
num=1
a=rdpcap("pcap1.pcap")               #循环打开文件
while True:
  try:
    num+=1
    file_name="pcap%d.pcap" % num
    b=rdpcap(file_name)
    a=a+b
  except:
    break
    print "[*] Read pcap file ok"
print "[*] Begin to parse pcapfile..."
print a
try:
  #print "[*] OPen new pcap_file %s" % pcap_file
  sessions=a.sessions()
  for session in sessions:
    print "[*]New session %s" % session
    data_payload=""
    for packet in sessions[session]:
      try:
        data_payload +=str(packet[TCP].payload)
        print "[**] Data:%s" % data_payload
      except:
        pass
except:
  print "[*]no pcapfile..."