[包编辑]修复包的checksum

[包编辑]修复包的checksum

如果我们修改了pcap的内容，之后会导致在TCP层里的checksum不对，这时我们就需要重新生成新的cksum并将Checksum字段修改正确，可使用如下脚本：

from scapy.all import *
import sys
import logging
logging.getLogger("scapy").setLevel(1)
 
if len(sys.argv) != 2:
    print("Usage:./ChecksumFixer  <input_pcap_file> <output_pcap_file>")
    print("Example: ./ChecksumFixer input.pcap output.pcap")
    sys.exit(1)
# ------------------------Command Line Argument---------------------------------------
input_file = sys.argv[1]
output_file = sys.argv[2]
# ------------------------Get The layer and Fix Checksum-------------------------------
def getLayer(p):
    for paktype in (IP, TCP, UDP, ICMP):
        try:
            p.getlayer(paktype).chksum = None
        except AttributeError:
            pass
    return p
# -----------------------FixPcap in input file and write to output fi`enter code here`le----------------
 
def fixpcap():
    paks = rdpcap(input_file)
    fc = map(getLayer, paks)
    wrpcap(output_file, fc)
 
if __name__ == '__main__':
    fixpcap()