89 lines
2.9 KiB
Python
89 lines
2.9 KiB
Python
import sys
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import time
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import threading
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from scapy.all import Ether, IP, UDP, send, sendp, Raw, sniff
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global initial_timestamp
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initial_timestamp = int(time.time() * 1000)
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# Simulated ACK sending function
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def send_ack(destination_IP, my_port, sender_port):
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ack_data = ""
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###################
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# With localhost:
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ack_packet = (
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IP(dst=destination_IP)
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/ UDP(dport=sender_port, sport=my_port)
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/ Raw(load=str(ack_data))
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)
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send(ack_packet, verbose=False)
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###################
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# With netns:
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# ack_packet = Ether(dst="00:00:00:00:00:04", src="00:00:00:00:00:01") / IP(dst="127.0.0.1") / UDP(dport=5551) / Raw(load=str(ack_data))
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# sendp(ack_packet, verbose=False)
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###################
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print(f"Sent ACK: {ack_data}")
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# Process incoming packets
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def process_packet(pkt):
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################### Save timestamps ###################
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if Raw in pkt:
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with open(save_file, "a") as f: # open as "a" for append
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global initial_timestamp
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receival_time = str(
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int(time.time() * 1000) - initial_timestamp
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) # time of arrival at receiver
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send_time = pkt[Raw].load # time it was sent from the sender
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################### Conversion & error handling ###################
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try:
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send_time = int(
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send_time.decode("utf-8").split("X")[0]
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) # decode the payload and stop at "X"
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except (
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ValueError
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): # For the last packet without a timestamp but "END" as payload
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print(f"END for {my_port}")
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send_ack(destination_IP, my_port, sender_port)
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return
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except Exception as e:
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print(f"Decoding error at {my_port}")
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send_ack(destination_IP, my_port, sender_port)
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return
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################### Write data ###################
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aoi = int(receival_time) - send_time
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f.write(f"{send_time},{receival_time},{aoi}\n")
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send_ack(destination_IP, my_port, sender_port)
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# Main loop
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def main(destination_IP, my_port, sender_port):
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###################
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# With localhost:
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sniff(
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iface="lo",
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filter=f"udp and dst port {my_port}",
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prn=process_packet,
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store=False,
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)
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###################
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# With netns:
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# sniff(iface="ns-g", filter=f"udp and dst port {my_port}", prn=process_packet, store=False)
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###################
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if __name__ == "__main__":
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if len(sys.argv) != 4:
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print(
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"Usage: python receive_and_ack.py <destination_IP> <my_port> <sender_port>"
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)
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sys.exit(1)
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destination_IP = sys.argv[1] # Clear
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my_port = int(sys.argv[2]) # Port to listen on
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sender_port = int(sys.argv[3]) # Port to send acks to
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save_file = f"timestamps_{my_port}"
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main(destination_IP, my_port, sender_port)
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