39 lines
814 B
Python
39 lines
814 B
Python
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#!/usr/bin/env python3
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# drop_icmp_v4.py
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# Requirements: NetfilterQueue, scapy
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import sys
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from netfilterqueue import NetfilterQueue
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from scapy.all import IP
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def on_packet(pkt):
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data = pkt.get_payload()
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try:
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ip = IP(data)
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# IPv4 ICMP protocol number == 1
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if ip.proto == 1:
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pkt.drop()
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return
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except Exception:
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# parsing error -> accept (conservative choice)
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pass
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pkt.accept()
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def main():
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if len(sys.argv) < 2:
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print("Usage: drop_icmp_v4.py <QUEUE_NUM>", file=sys.stderr)
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sys.exit(1)
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qnum = int(sys.argv[1])
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nfq = NetfilterQueue()
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nfq.bind(qnum, on_packet)
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try:
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nfq.run()
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except KeyboardInterrupt:
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pass
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finally:
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nfq.unbind()
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if __name__ == "__main__":
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main()
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