tcp-serv-rst.py

#!/usr/bin/env python3

import argparse
import socket
import struct
from time import sleep

FRAG1 = b"""HTTP/1.0 200 OK\r
Server: netcat\r
Content-Type: text/plain\r
Content-Length: 300\r
\r
asdfasdfsdf
asdf
--------------------
234234234
^Z"""

def main():
    argp = argparse.ArgumentParser()
    argp.add_argument('host', default='localhost',
                      help="which address to bind on")
    argp.add_argument('port', default=8097, type=int,
                      help="which port to listen on")
    opts = argp.parse_args()
    # --- #

    gai = socket.getaddrinfo(opts.host, opts.port,
                             socket.AF_INET, socket.SOCK_STREAM,
                             flags=socket.AI_ADDRCONFIG)
    print(f"Resolved to {len(gai)} address pair(s):")
    for addrinfo in gai:
        print(f" - {addrinfo}")

    while True:
        try:
            for addrinfo in gai:
                s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
                s.setsockopt(socket.SOL_SOCKET,
                             socket.SO_LINGER,
                             struct.pack('ii', 1, 0))

                print(f"binding {addrinfo[4]}")
                s.bind(addrinfo[4])
                print("Listening...")
                s.listen()

                connection, (clientaddr, clientport) = s.accept()
                print(f"Accepted connection from {clientaddr}:{clientport}.")
                _request = connection.recv(1024)
                sleep(0.128)
                connection.send(FRAG1)
                print(f"Sent response len {len(FRAG1)}:\n{FRAG1!r}")
                sleep(0.3)
                #-- With SO_LINGER set, sends RST
                connection.close()
                print("*** RST sent! ***")

                print()
                sleep(3.5)
        except KeyboardInterrupt:
            break


if __name__ == "__main__":
    import sys
    sys.exit(main())