UDP Broadcast Server and Client

broadcast.py

import socket
import time


def serve(port):
    with socket.socket(socket.AF_INET, socket.SOCK_DGRAM) as sock:
        sock.setsockopt(socket.SOL_SOCKET, socket.SO_BROADCAST, 1)
        while True:
            sock.sendto(bytes(time.ctime(), encoding='utf-8'), ('<broadcast>', port))
            time.sleep(1)


def monitor(port):
    with socket.socket(socket.AF_INET, socket.SOCK_DGRAM, socket.IPPROTO_UDP) as sock:
        sock.bind(('', port))
        while True:
            content, address = sock.recvfrom(64)
            print(f'\r> {address[0]}:{address[1]}: {content.decode("utf-8")}', end='')


if __name__ == '__main__':
    import argparse
    import multiprocessing
    
    parser = argparse.ArgumentParser(description='serve and/or monitor UDP broadcast traffic')
    parser.add_argument('-p', '--port', type=int, default=5606)
    parser.add_argument('-s', '--serve', action='store_true', help='broadcast traffic')
    parser.add_argument('-m', '--monitor', action='store_true', help='listen for traffic')

    args = parser.parse_args()

    if not (args.serve or args.monitor):
        parser.error('no action specified: expected at least one of --serve, --monitor')

    processes = []

    if args.serve:
        processes.append(multiprocessing.Process(target=serve, args=(args.port,)))
    if args.monitor:
        processes.append(multiprocessing.Process(target=monitor, args=(args.port,)))

    for process in processes:
        process.start()

    try:
        while True:
            time.sleep(0.1)
    except KeyboardInterrupt:
        print('\nstopping...')
        for process in processes:
            process.terminate()