#!/usr/bin/env python # # Redirect data from a TCP/IP connection to a serial port and vice versa. # # (C) 2002-2020 Chris Liechti # # 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()