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Diffstat (limited to 'examples/rfc2217_server.py')
| -rw-r--r-- | examples/rfc2217_server.py | 204 |
1 files changed, 204 insertions, 0 deletions
diff --git a/examples/rfc2217_server.py b/examples/rfc2217_server.py new file mode 100644 index 0000000..81fb520 --- /dev/null +++ b/examples/rfc2217_server.py @@ -0,0 +1,204 @@ +#!/usr/bin/env python + +# (C) 2009 Chris Liechti <cliechti@gmx.net> +# redirect data from a TCP/IP connection to a serial port and vice versa +# using RFC 2217 + + +import sys +import os +import threading +import time +import socket +import serial +import serial.rfc2217 +import logging + +class Redirector: + def __init__(self, serial_instance, socket, debug=None): + self.serial = serial_instance + self.socket = socket + self._write_lock = threading.Lock() + self.rfc2217 = serial.rfc2217.PortManager( + self.serial, + self, + logger = (debug and logging.getLogger('rfc2217.server')) + ) + self.log = logging.getLogger('redirector') + + def statusline_poller(self): + self.log.debug('status line poll thread started') + while self.alive: + time.sleep(1) + self.rfc2217.check_modem_lines() + self.log.debug('status line poll thread terminated') + + def shortcut(self): + """connect the serial port to the TCP port by copying everything + from one side to the other""" + self.alive = True + self.thread_read = threading.Thread(target=self.reader) + self.thread_read.setDaemon(True) + self.thread_read.setName('serial->socket') + self.thread_read.start() + self.thread_poll = threading.Thread(target=self.statusline_poller) + self.thread_poll.setDaemon(True) + self.thread_poll.setName('status line poll') + self.thread_poll.start() + self.writer() + + def reader(self): + """loop forever and copy serial->socket""" + self.log.debug('reader thread started') + while self.alive: + try: + data = self.serial.read(1) # read one, blocking + n = self.serial.inWaiting() # look if there is more + if n: + data = data + self.serial.read(n) # and get as much as possible + if data: + # escape outgoing data when needed (Telnet IAC (0xff) character) + data = serial.to_bytes(self.rfc2217.escape(data)) + self._write_lock.acquire() + try: + self.socket.sendall(data) # send it over TCP + finally: + self._write_lock.release() + except socket.error, msg: + self.log.error('%s' % (msg,)) + # probably got disconnected + break + self.alive = False + self.log.debug('reader thread terminated') + + def write(self, data): + """thread safe socket write with no data escaping. used to send telnet stuff""" + self._write_lock.acquire() + try: + self.socket.sendall(data) + finally: + self._write_lock.release() + + def writer(self): + """loop forever and copy socket->serial""" + while self.alive: + try: + data = self.socket.recv(1024) + if not data: + break + self.serial.write(serial.to_bytes(self.rfc2217.filter(data))) + except socket.error, msg: + self.log.error('%s' % (msg,)) + # probably got disconnected + break + self.stop() + + def stop(self): + """Stop copying""" + self.log.debug('stopping') + if self.alive: + self.alive = False + self.thread_read.join() + self.thread_poll.join() + + +if __name__ == '__main__': + import optparse + + parser = optparse.OptionParser( + usage = "%prog [options] port", + description = "RFC 2217 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_option("-p", "--localport", + dest = "local_port", + action = "store", + type = 'int', + help = "local TCP port", + default = 2217 + ) + + parser.add_option("-v", "--verbose", + dest = "verbosity", + action = "count", + help = "print more diagnostic messages (option can be given multiple times)", + default = 0 + ) + + (options, args) = parser.parse_args() + + if len(args) != 1: + parser.error('serial port name required as argument') + + if options.verbosity > 3: + options.verbosity = 3 + level = ( + logging.WARNING, + logging.INFO, + logging.DEBUG, + logging.NOTSET, + )[options.verbosity] + logging.basicConfig(level=logging.INFO) + logging.getLogger('root').setLevel(logging.INFO) + logging.getLogger('rfc2217').setLevel(level) + + # connect to serial port + ser = serial.Serial() + ser.port = args[0] + ser.timeout = 3 # required so that the reader thread can exit + + logging.info("RFC 2217 TCP/IP to Serial redirector - type Ctrl-C / BREAK to quit") + + try: + ser.open() + except serial.SerialException, e: + logging.error("Could not open serial port %s: %s" % (ser.portstr, e)) + sys.exit(1) + + logging.info("Serving serial port: %s" % (ser.portstr,)) + settings = ser.getSettingsDict() + # reset contol line as no _remote_ "terminal" has been connected yet + ser.setDTR(False) + ser.setRTS(False) + + srv = socket.socket(socket.AF_INET, socket.SOCK_STREAM) + srv.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1) + srv.bind( ('', options.local_port) ) + srv.listen(1) + logging.info("TCP/IP port: %s" % (options.local_port,)) + while True: + try: + connection, addr = srv.accept() + logging.info('Connected by %s:%s' % (addr[0], addr[1])) + connection.setsockopt( socket.IPPROTO_TCP, socket.TCP_NODELAY, 1) + ser.setRTS(True) + ser.setDTR(True) + # enter network <-> serial loop + r = Redirector( + ser, + connection, + options.verbosity > 0 + ) + try: + r.shortcut() + finally: + logging.info('Disconnected') + r.stop() + connection.close() + ser.setDTR(False) + ser.setRTS(False) + # Restore port settings (may have been changed by RFC 2217 capable + # client) + ser.applySettingsDict(settings) + except KeyboardInterrupt: + break + except socket.error, msg: + logging.error('%s' % (msg,)) + + logging.info('--- exit ---') |