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Diffstat (limited to 'examples/tcp_serial_redirect.py')
| -rwxr-xr-x | examples/tcp_serial_redirect.py | 230 |
1 files changed, 230 insertions, 0 deletions
diff --git a/examples/tcp_serial_redirect.py b/examples/tcp_serial_redirect.py new file mode 100755 index 0000000..bd7db77 --- /dev/null +++ b/examples/tcp_serial_redirect.py @@ -0,0 +1,230 @@ +#!/usr/bin/env python +# +# Redirect data from a TCP/IP connection to a serial port and vice versa. +# +# (C) 2002-2020 Chris Liechti <cliechti@gmx.net> +# +# SPDX-License-Identifier: BSD-3-Clause + +import sys +import socket +import serial +import serial.threaded +import time + + +class SerialToNet(serial.threaded.Protocol): + """serial->socket""" + + def __init__(self): + self.socket = None + + def __call__(self): + return self + + def data_received(self, data): + if self.socket is not None: + self.socket.sendall(data) + + +if __name__ == '__main__': # noqa + import argparse + + parser = argparse.ArgumentParser( + description='Simple Serial to Network (TCP/IP) redirector.', + epilog="""\ +NOTE: no security measures are implemented. Anyone can remotely connect +to this service over the network. + +Only one connection at once is supported. When the connection is terminated +it waits for the next connect. +""") + + parser.add_argument( + 'SERIALPORT', + help="serial port name") + + parser.add_argument( + 'BAUDRATE', + type=int, + nargs='?', + help='set baud rate, default: %(default)s', + default=9600) + + parser.add_argument( + '-q', '--quiet', + action='store_true', + help='suppress non error messages', + default=False) + + parser.add_argument( + '--develop', + action='store_true', + help='Development mode, prints Python internals on errors', + default=False) + + group = parser.add_argument_group('serial port') + + group.add_argument( + "--bytesize", + choices=[5, 6, 7, 8], + type=int, + help="set bytesize, one of {5 6 7 8}, default: 8", + default=8) + + group.add_argument( + "--parity", + choices=['N', 'E', 'O', 'S', 'M'], + type=lambda c: c.upper(), + help="set parity, one of {N E O S M}, default: N", + default='N') + + group.add_argument( + "--stopbits", + choices=[1, 1.5, 2], + type=float, + help="set stopbits, one of {1 1.5 2}, default: 1", + default=1) + + group.add_argument( + '--rtscts', + action='store_true', + help='enable RTS/CTS flow control (default off)', + default=False) + + group.add_argument( + '--xonxoff', + action='store_true', + help='enable software flow control (default off)', + default=False) + + group.add_argument( + '--rts', + type=int, + help='set initial RTS line state (possible values: 0, 1)', + default=None) + + group.add_argument( + '--dtr', + type=int, + help='set initial DTR line state (possible values: 0, 1)', + default=None) + + group = parser.add_argument_group('network settings') + + exclusive_group = group.add_mutually_exclusive_group() + + exclusive_group.add_argument( + '-P', '--localport', + type=int, + help='local TCP port', + default=7777) + + exclusive_group.add_argument( + '-c', '--client', + metavar='HOST:PORT', + help='make the connection as a client, instead of running a server', + default=False) + + args = parser.parse_args() + + # connect to serial port + ser = serial.serial_for_url(args.SERIALPORT, do_not_open=True) + ser.baudrate = args.BAUDRATE + ser.bytesize = args.bytesize + ser.parity = args.parity + ser.stopbits = args.stopbits + ser.rtscts = args.rtscts + ser.xonxoff = args.xonxoff + + if args.rts is not None: + ser.rts = args.rts + + if args.dtr is not None: + ser.dtr = args.dtr + + if not args.quiet: + sys.stderr.write( + '--- TCP/IP to Serial redirect on {p.name} {p.baudrate},{p.bytesize},{p.parity},{p.stopbits} ---\n' + '--- type Ctrl-C / BREAK to quit\n'.format(p=ser)) + + try: + ser.open() + except serial.SerialException as e: + sys.stderr.write('Could not open serial port {}: {}\n'.format(ser.name, e)) + sys.exit(1) + + ser_to_net = SerialToNet() + serial_worker = serial.threaded.ReaderThread(ser, ser_to_net) + serial_worker.start() + + if not args.client: + srv = socket.socket(socket.AF_INET, socket.SOCK_STREAM) + srv.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1) + srv.bind(('', args.localport)) + srv.listen(1) + try: + intentional_exit = False + while True: + if args.client: + host, port = args.client.split(':') + sys.stderr.write("Opening connection to {}:{}...\n".format(host, port)) + client_socket = socket.socket() + try: + client_socket.connect((host, int(port))) + except socket.error as msg: + sys.stderr.write('WARNING: {}\n'.format(msg)) + time.sleep(5) # intentional delay on reconnection as client + continue + sys.stderr.write('Connected\n') + client_socket.setsockopt(socket.IPPROTO_TCP, socket.TCP_NODELAY, 1) + #~ client_socket.settimeout(5) + else: + sys.stderr.write('Waiting for connection on {}...\n'.format(args.localport)) + client_socket, addr = srv.accept() + sys.stderr.write('Connected by {}\n'.format(addr)) + # More quickly detect bad clients who quit without closing the + # connection: After 1 second of idle, start sending TCP keep-alive + # packets every 1 second. If 3 consecutive keep-alive packets + # fail, assume the client is gone and close the connection. + try: + client_socket.setsockopt(socket.IPPROTO_TCP, socket.TCP_KEEPIDLE, 1) + client_socket.setsockopt(socket.IPPROTO_TCP, socket.TCP_KEEPINTVL, 1) + client_socket.setsockopt(socket.IPPROTO_TCP, socket.TCP_KEEPCNT, 3) + client_socket.setsockopt(socket.SOL_SOCKET, socket.SO_KEEPALIVE, 1) + except AttributeError: + pass # XXX not available on windows + client_socket.setsockopt(socket.IPPROTO_TCP, socket.TCP_NODELAY, 1) + try: + ser_to_net.socket = client_socket + # enter network <-> serial loop + while True: + try: + data = client_socket.recv(1024) + if not data: + break + ser.write(data) # get a bunch of bytes and send them + except socket.error as msg: + if args.develop: + raise + sys.stderr.write('ERROR: {}\n'.format(msg)) + # probably got disconnected + break + except KeyboardInterrupt: + intentional_exit = True + raise + except socket.error as msg: + if args.develop: + raise + sys.stderr.write('ERROR: {}\n'.format(msg)) + finally: + ser_to_net.socket = None + sys.stderr.write('Disconnected\n') + client_socket.close() + if args.client and not intentional_exit: + time.sleep(5) # intentional delay on reconnection as client + except KeyboardInterrupt: + pass + + sys.stderr.write('\n--- exit ---\n') + serial_worker.stop() |