107 lines
2.4 KiB
Python
107 lines
2.4 KiB
Python
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from scapy.all import *
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import socket
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import struct
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import hmac
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import hashlib
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keyd = '123'
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def calculate_tcp_length(pkt):
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iphdr_len = pkt[IP].ihl * 4
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total_len = pkt[IP].len
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tcp_hdrlen = pkt[TCP].dataofs * 4
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tcp_payload_len = total_len - iphdr_len - tcp_hdrlen
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return tcp_payload_len
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def refill_tcp_pseudo_header(pkt):
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destination = pkt[IP].dst
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source = pkt[IP].src
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reserved = 0
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protocol = socket.IPPROTO_TCP
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tcp_hdrlen = pkt[TCP].dataofs *4
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tcp_payload_len =calculate_tcp_length(pkt)
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total_length = tcp_hdrlen + tcp_payload_len
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print("!!!!!!!!!!!!!!!!!!!!!!!!")
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print(destination)
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print(source)
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destination_ip = int(socket.inet_aton(destination).encode('hex'),16)
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source_ip = int(socket.inet_aton(source).encode('hex'),16)
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print("%%%%%%%%%%%%%%%%%%%")
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print(destination_ip)
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destination_ip = struct.pack("!I",destination_ip)
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print(repr(destination_ip))
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print(source_ip)
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source_ip = struct.pack("!I",source_ip)
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print(repr(source_ip))
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print("^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^")
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#pseudo header
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psh = struct.pack("!4s4sBBH",
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source_ip,
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destination_ip,
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reserved,
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protocol,
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total_length
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)
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print(hexdump(psh))
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return psh
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def get_tcp_header(pkt):
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pkt = pkt[IP]
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iphdr_len = pkt[IP].ihl * 4
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tcp_header = pkt[iphdr_len:iphdr_len+20]
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tcp_payload = pkt[iphdr_len+20:]
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def analysis_pkt(pkt):
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ip = pkt[IP]
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print(repr(ip))
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print("#####################")
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print(hexdump(ip))
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tcp = pkt[TCP]
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print(repr(tcp))
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print("#####################")
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tcp_options = pkt[TCP].options
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print(repr(tcp_options))
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print("#####################")
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tcp_load = pkt[TCP].payload
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print(repr(tcp_load))
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print("#####################")
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psh = refill_tcp_pseudo_header(pkt)
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iphdr_len = pkt[IP].ihl * 4
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tcp_hdrlen = pkt[TCP].dataofs * 4
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pkt[TCP].chksum = 0
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pkt = str(pkt[IP])
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tcp_header = pkt[iphdr_len:iphdr_len+20]
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tcp_payload = pkt[iphdr_len+tcp_hdrlen:]
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print(hexdump(tcp_header))
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print(hexdump(tcp_payload))
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tcp = psh + tcp_header + tcp_payload
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print(hexdump(tcp))
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res = hmac.new(keyd, tcp, hashlib.md5).digest()
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print(hexdump(res))
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def main():
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try:
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pkts = rdpcap('test.pcap')
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print("len=",len(pkts))
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print("len=",len(str(pkts[0])))
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for pktno in range(len(pkts)):
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print(repr(pkts[pktno]))
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print("#####################")
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analysis_pkt(pkts[pktno])
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except Scapy_Exception as e:
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print(e)
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if __name__=="__main__":
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main()
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