#! python
#
# This module implements a RFC2217 compatible client. RF2217 descibes a
# protocol to access serial ports over TCP/IP and allows setting the baud rate,
# modem control lines etc.
#
# This file is part of pySerial. https://github.com/pyserial/pyserial
# (C) 2001-2015 Chris Liechti <cliechti@gmx.net>
#
# SPDX-License-Identifier: BSD-3-Clause
# TODO:
# - setting control line -> answer is not checked (had problems with one of the
# severs). consider implementing a compatibility mode flag to make check
# conditional
# - write timeout not implemented at all
# ###########################################################################
# observations and issues with servers
# ===========================================================================
# sredird V2.2.1
# - http://www.ibiblio.org/pub/Linux/system/serial/ sredird-2.2.2.tar.gz
# - does not acknowledge SET_CONTROL (RTS/DTR) correctly, always responding
# [105 1] instead of the actual value.
# - SET_BAUDRATE answer contains 4 extra null bytes -> probably for larger
# numbers than 2**32?
# - To get the signature [COM_PORT_OPTION 0] has to be sent.
# - run a server: while true; do nc -l -p 7000 -c "sredird debug /dev/ttyUSB0 /var/lock/sredir"; done
# ===========================================================================
# telnetcpcd (untested)
# - http://ftp.wayne.edu/kermit/sredird/telnetcpcd-1.09.tar.gz
# - To get the signature [COM_PORT_OPTION] w/o data has to be sent.
# ===========================================================================
# ser2net
# - does not negotiate BINARY or COM_PORT_OPTION for his side but at least
# acknowledges that the client activates these options
# - The configuration may be that the server prints a banner. As this client
# implementation does a flushInput on connect, this banner is hidden from
# the user application.
# - NOTIFY_MODEMSTATE: the poll interval of the server seems to be one
# second.
# - To get the signature [COM_PORT_OPTION 0] has to be sent.
# - run a server: run ser2net daemon, in /etc/ser2net.conf:
# 2000:telnet:0:/dev/ttyS0:9600 remctl banner
# ###########################################################################
# How to identify ports? pySerial might want to support other protocols in the
# future, so lets use an URL scheme.
# for RFC2217 compliant servers we will use this:
# rfc2217://<host>:<port>[?option[&option...]]
#
# options:
# - "logging" set log level print diagnostic messages (e.g. "logging=debug")
# - "ign_set_control": do not look at the answers to SET_CONTROL
# - "poll_modem": issue NOTIFY_MODEMSTATE requests when CTS/DTR/RI/CD is read.
# Without this option it expects that the server sends notifications
# automatically on change (which most servers do and is according to the
# RFC).
# the order of the options is not relevant
import logging
import socket
import struct
import threading
import time
try:
import urlparse
except ImportError:
import urllib.parse as urlparse
try:
import Queue
except ImportError:
import queue as Queue
import serial
from serial.serialutil import SerialBase, SerialException, to_bytes, iterbytes, portNotOpenError
# port string is expected to be something like this:
# rfc2217://host:port
# host may be an IP or including domain, whatever.
# port is 0...65535
# map log level names to constants. used in from_url()
LOGGER_LEVELS = {
'debug': logging.DEBUG,
'info': logging.INFO,
'warning': logging.WARNING,
'error': logging.ERROR,
}
# telnet protocol characters
SE = b'\xf0' # Subnegotiation End
NOP = b'\xf1' # No Operation
DM = b'\xf2' # Data Mark
BRK = b'\xf3' # Break
IP = b'\xf4' # Interrupt process
AO = b'\xf5' # Abort output
AYT = b'\xf6' # Are You There
EC = b'\xf7' # Erase Character
EL = b'\xf8' # Erase Line
GA = b'\xf9' # Go Ahead
SB = b'\xfa' # Subnegotiation Begin
WILL = b'\xfb'
WONT = b'\xfc'
DO = b'\xfd'
DONT = b'\xfe'
IAC = b'\xff' # Interpret As Command
IAC_DOUBLED = b'\xff\xff'
# selected telnet options
BINARY = b'\x00' # 8-bit data path
ECHO = b'\x01' # echo
SGA = b'\x03' # suppress go ahead
# RFC2217
COM_PORT_OPTION = b'\x2c'
# Client to Access Server
SET_BAUDRATE = b'\x01'
SET_DATASIZE = b'\x02'
SET_PARITY = b'\x03'
SET_STOPSIZE = b'\x04'
SET_CONTROL = b'\x05'
NOTIFY_LINESTATE = b'\x06'
NOTIFY_MODEMSTATE = b'\x07'
FLOWCONTROL_SUSPEND = b'\x08'
FLOWCONTROL_RESUME = b'\x09'
SET_LINESTATE_MASK = b'\x0a'
SET_MODEMSTATE_MASK = b'\x0b'
PURGE_DATA = b'\x0c'
SERVER_SET_BAUDRATE = b'\x65'
SERVER_SET_DATASIZE = b'\x66'
SERVER_SET_PARITY = b'\x67'
SERVER_SET_STOPSIZE = b'\x68'
SERVER_SET_CONTROL = b'\x69'
SERVER_NOTIFY_LINESTATE = b'\x6a'
SERVER_NOTIFY_MODEMSTATE = b'\x6b'
SERVER_FLOWCONTROL_SUSPEND = b'\x6c'
SERVER_FLOWCONTROL_RESUME = b'\x6d'
SERVER_SET_LINESTATE_MASK = b'\x6e'
SERVER_SET_MODEMSTATE_MASK = b'\x6f'
SERVER_PURGE_DATA = b'\x70'
RFC2217_ANSWER_MAP = {
SET_BAUDRATE: SERVER_SET_BAUDRATE,
SET_DATASIZE: SERVER_SET_DATASIZE,
SET_PARITY: SERVER_SET_PARITY,
SET_STOPSIZE: SERVER_SET_STOPSIZE,
SET_CONTROL: SERVER_SET_CONTROL,
NOTIFY_LINESTATE: SERVER_NOTIFY_LINESTATE,
NOTIFY_MODEMSTATE: SERVER_NOTIFY_MODEMSTATE,
FLOWCONTROL_SUSPEND: SERVER_FLOWCONTROL_SUSPEND,
FLOWCONTROL_RESUME: SERVER_FLOWCONTROL_RESUME,
SET_LINESTATE_MASK: SERVER_SET_LINESTATE_MASK,
SET_MODEMSTATE_MASK: SERVER_SET_MODEMSTATE_MASK,
PURGE_DATA: SERVER_PURGE_DATA,
}
SET_CONTROL_REQ_FLOW_SETTING = b'\x00' # Request Com Port Flow Control Setting (outbound/both)
SET_CONTROL_USE_NO_FLOW_CONTROL = b'\x01' # Use No Flow Control (outbound/both)
SET_CONTROL_USE_SW_FLOW_CONTROL = b'\x02' # Use XON/XOFF Flow Control (outbound/both)
SET_CONTROL_USE_HW_FLOW_CONTROL = b'\x03' # Use HARDWARE Flow Control (outbound/both)
SET_CONTROL_REQ_BREAK_STATE = b'\x04' # Request BREAK State
SET_CONTROL_BREAK_ON = b'\x05' # Set BREAK State ON
SET_CONTROL_BREAK_OFF = b'\x06' # Set BREAK State OFF
SET_CONTROL_REQ_DTR = b'\x07' # Request DTR Signal State
SET_CONTROL_DTR_ON = b'\x08' # Set DTR Signal State ON
SET_CONTROL_DTR_OFF = b'\x09' # Set DTR Signal State OFF
SET_CONTROL_REQ_RTS = b'\x0a' # Request RTS Signal State
SET_CONTROL_RTS_ON = b'\x0b' # Set RTS Signal State ON
SET_CONTROL_RTS_OFF = b'\x0c' # Set RTS Signal State OFF
SET_CONTROL_REQ_FLOW_SETTING_IN = b'\x0d' # Request Com Port Flow Control Setting (inbound)
SET_CONTROL_USE_NO_FLOW_CONTROL_IN = b'\x0e' # Use No Flow Control (inbound)
SET_CONTROL_USE_SW_FLOW_CONTOL_IN = b'\x0f' # Use XON/XOFF Flow Control (inbound)
SET_CONTROL_USE_HW_FLOW_CONTOL_IN = b'\x10' # Use HARDWARE Flow Control (inbound)
SET_CONTROL_USE_DCD_FLOW_CONTROL = b'\x11' # Use DCD Flow Control (outbound/both)
SET_CONTROL_USE_DTR_FLOW_CONTROL = b'\x12' # Use DTR Flow Control (inbound)
SET_CONTROL_USE_DSR_FLOW_CONTROL = b'\x13' # Use DSR Flow Control (outbound/both)
LINESTATE_MASK_TIMEOUT = 128 # Time-out Error
LINESTATE_MASK_SHIFTREG_EMPTY = 64 # Transfer Shift Register Empty
LINESTATE_MASK_TRANSREG_EMPTY = 32 # Transfer Holding Register Empty
LINESTATE_MASK_BREAK_DETECT = 16 # Break-detect Error
LINESTATE_MASK_FRAMING_ERROR = 8 # Framing Error
LINESTATE_MASK_PARTIY_ERROR = 4 # Parity Error
LINESTATE_MASK_OVERRUN_ERROR = 2 # Overrun Error
LINESTATE_MASK_DATA_READY = 1 # Data Ready
MODEMSTATE_MASK_CD = 128 # Receive Line Signal Detect (also known as Carrier Detect)
MODEMSTATE_MASK_RI = 64 # Ring Indicator
MODEMSTATE_MASK_DSR = 32 # Data-Set-Ready Signal State
MODEMSTATE_MASK_CTS = 16 # Clear-To-Send Signal State
MODEMSTATE_MASK_CD_CHANGE = 8 # Delta Receive Line Signal Detect
MODEMSTATE_MASK_RI_CHANGE = 4 # Trailing-edge Ring Detector
MODEMSTATE_MASK_DSR_CHANGE = 2 # Delta Data-Set-Ready
MODEMSTATE_MASK_CTS_CHANGE = 1 # Delta Clear-To-Send
PURGE_RECEIVE_BUFFER = b'\x01' # Purge access server receive data buffer
PURGE_TRANSMIT_BUFFER = b'\x02' # Purge access server transmit data buffer
PURGE_BOTH_BUFFERS = b'\x03' # Purge both the access server receive data buffer and the access server transmit data buffer
RFC2217_PARITY_MAP = {
serial.PARITY_NONE: 1,
serial.PARITY_ODD: 2,
serial.PARITY_EVEN: 3,
serial.PARITY_MARK: 4,
serial.PARITY_SPACE: 5,
}
RFC2217_REVERSE_PARITY_MAP = dict((v, k) for k, v in RFC2217_PARITY_MAP.items())
RFC2217_STOPBIT_MAP = {
serial.STOPBITS_ONE: 1,
serial.STOPBITS_ONE_POINT_FIVE: 3,
serial.STOPBITS_TWO: 2,
}
RFC2217_REVERSE_STOPBIT_MAP = dict((v, k) for k, v in RFC2217_STOPBIT_MAP.items())
# Telnet filter states
M_NORMAL = 0
M_IAC_SEEN = 1
M_NEGOTIATE = 2
# TelnetOption and TelnetSubnegotiation states
REQUESTED = 'REQUESTED'
ACTIVE = 'ACTIVE'
INACTIVE = 'INACTIVE'
REALLY_INACTIVE = 'REALLY_INACTIVE'
class TelnetOption(object):
"""Manage a single telnet option, keeps track of DO/DONT WILL/WONT."""
def __init__(self, connection, name, option, send_yes, send_no, ack_yes, ack_no, initial_state, activation_callback=None):
"""\
Initialize option.
:param connection: connection used to transmit answers
:param name: a readable name for debug outputs
:param send_yes: what to send when option is to be enabled.
:param send_no: what to send when option is to be disabled.
:param ack_yes: what to expect when remote agrees on option.
:param ack_no: what to expect when remote disagrees on option.
:param initial_state: options initialized with REQUESTED are tried to
be enabled on startup. use INACTIVE for all others.
"""
self.connection = connection
self.name = name
self.option = option
self.send_yes = send_yes
self.send_no = send_no
self.ack_yes = ack_yes
self.ack_no = ack_no
self.state = initial_state
self.active = False
self.activation_callback = activation_callback
def __repr__(self):
"""String for debug outputs"""
return "%s:%s(%s)" % (self.name, self.active, self.state)
def process_incoming(self, command):
"""\
A DO/DONT/WILL/WONT was received for this option, update state and
answer when needed.
"""
if command == self.ack_yes:
if self.state is REQUESTED:
self.state = ACTIVE
self.active = True
if self.activation_callback is not None:
self.activation_callback()
elif self.state is ACTIVE:
pass
elif self.state is INACTIVE:
self.state = ACTIVE
self.connection.telnetSendOption(self.send_yes, self.option)
self.active = True
if self.activation_callback is not None:
self.activation_callback()
elif self.state is REALLY_INACTIVE:
self.connection.telnetSendOption(self.send_no, self.option)
else:
raise ValueError('option in illegal state %r' % self)
elif command == self.ack_no:
if self.state is REQUESTED:
self.state = INACTIVE
self.active = False
elif self.state is ACTIVE:
self.state = INACTIVE
self.connection.telnetSendOption(self.send_no, self.option)
self.active = False
elif self.state is INACTIVE:
pass
elif self.state is REALLY_INACTIVE:
pass
else:
raise ValueError('option in illegal state %r' % self)
class TelnetSubnegotiation(object):
"""\
A object to handle subnegotiation of options. In this case actually
sub-sub options for RFC 2217. It is used to track com port options.
"""
def __init__(self, connection, name, option, ack_option=None):
if ack_option is None:
ack_option = option
self.connection = connection
self.name = name
self.option = option
self.value = None
self.ack_option = ack_option
self.state = INACTIVE
def __repr__(self):
"""String for debug outputs."""
return "%s:%s" % (self.name, self.state)
def set(self, value):
"""\
Request a change of the value. a request is sent to the server. if
the client needs to know if the change is performed he has to check the
state of this object.
"""
self.value = value
self.state = REQUESTED
self.connection.rfc2217SendSubnegotiation(self.option, self.value)
if self.connection.logger:
self.connection.logger.debug("SB Requesting %s -> %r" % (self.name, self.value))
def isReady(self):
"""\
Check if answer from server has been received. when server rejects
the change, raise a ValueError.
"""
if self.state == REALLY_INACTIVE:
raise ValueError("remote rejected value for option %r" % (self.name))
return self.state == ACTIVE
# add property to have a similar interface as TelnetOption
active = property(isReady)
def wait(self, timeout=3):
"""\
Wait until the subnegotiation has been acknowledged or timeout. It
can also throw a value error when the answer from the server does not
match the value sent.
"""
timeout_time = time.time() + timeout
while time.time() < timeout_time:
time.sleep(0.05) # prevent 100% CPU load
if self.isReady():
break
else:
raise SerialException("timeout while waiting for option %r" % (self.name))
def checkAnswer(self, suboption):
"""\
Check an incoming subnegotiation block. The parameter already has
cut off the header like sub option number and com port option value.
"""
if self.value == suboption[:len(self.value)]:
self.state = ACTIVE
else:
# error propagation done in isReady
self.state = REALLY_INACTIVE
if self.connection.logger:
self.connection.logger.debug("SB Answer %s -> %r -> %s" % (self.name, suboption, self.state))
class Serial(SerialBase):
"""Serial port implementation for RFC 2217 remote serial ports."""
BAUDRATES = (50, 75, 110, 134, 150, 200, 300, 600, 1200, 1800, 2400, 4800,
9600, 19200, 38400, 57600, 115200)
def __init__(self, *args, **kwargs):
super(Serial, self).__init__(*args, **kwargs)
self._thread = None
self._socket = None
def open(self):
"""\
Open port with current settings. This may throw a SerialException
if the port cannot be opened.
"""
self.logger = None
self._ignore_set_control_answer = False
self._poll_modem_state = False
self._network_timeout = 3
if self._port is None:
raise SerialException("Port must be configured before it can be used.")
if self.is_open:
raise SerialException("Port is already open.")
try:
self._socket = socket.create_connection(self.from_url(self.portstr))
self._socket.setsockopt(socket.IPPROTO_TCP, socket.TCP_NODELAY, 1)
except Exception as msg:
self._socket = None
raise SerialException("Could not open port %s: %s" % (self.portstr, msg))
self._socket.settimeout(5) # XXX good value?
# use a thread save queue as buffer. it also simplifies implementing
# the read timeout
self._read_buffer = Queue.Queue()
# to ensure that user writes does not interfere with internal
# telnet/rfc2217 options establish a lock
self._write_lock = threading.Lock()
# name the following separately so that, below, a check can be easily done
mandadory_options = [
TelnetOption(self, 'we-BINARY', BINARY, WILL, WONT, DO, DONT, INACTIVE),
TelnetOption(self, 'we-RFC2217', COM_PORT_OPTION, WILL, WONT, DO, DONT, REQUESTED),
]
# all supported telnet options
self._telnet_options = [
TelnetOption(self, 'ECHO', ECHO, DO, DONT, WILL, WONT, REQUESTED),
TelnetOption(self, 'we-SGA', SGA, WILL, WONT, DO, DONT, REQUESTED),
TelnetOption(self, 'they-SGA', SGA, DO, DONT, WILL, WONT, REQUESTED),
TelnetOption(self, 'they-BINARY', BINARY, DO, DONT, WILL, WONT, INACTIVE),
TelnetOption(self, 'they-RFC2217', COM_PORT_OPTION, DO, DONT, WILL, WONT, REQUESTED),
] + mandadory_options
# RFC 2217 specific states
# COM port settings
self._rfc2217_port_settings = {
'baudrate': TelnetSubnegotiation(self, 'baudrate', SET_BAUDRATE, SERVER_SET_BAUDRATE),
'datasize': TelnetSubnegotiation(self, 'datasize', SET_DATASIZE, SERVER_SET_DATASIZE),
'parity': TelnetSubnegotiation(self, 'parity', SET_PARITY, SERVER_SET_PARITY),
'stopsize': TelnetSubnegotiation(self, 'stopsize', SET_STOPSIZE, SERVER_SET_STOPSIZE),
}
# There are more subnegotiation objects, combine all in one dictionary
# for easy access
self._rfc2217_options = {
'purge': TelnetSubnegotiation(self, 'purge', PURGE_DATA, SERVER_PURGE_DATA),
'control': TelnetSubnegotiation(self, 'control', SET_CONTROL, SERVER_SET_CONTROL),
}
self._rfc2217_options.update(self._rfc2217_port_settings)
# cache for line and modem states that the server sends to us
self._linestate = 0
self._modemstate = None
self._modemstate_expires = 0
# RFC 2217 flow control between server and client
self._remote_suspend_flow = False
self.is_open = True
self._thread = threading.Thread(target=self._telnetReadLoop)
self._thread.setDaemon(True)
self._thread.setName('pySerial RFC 2217 reader thread for %s' % (self._port,))
self._thread.start()
try: # must clean-up if open fails
# negotiate Telnet/RFC 2217 -> send initial requests
for option in self._telnet_options:
if option.state is REQUESTED:
self.telnetSendOption(option.send_yes, option.option)
# now wait until important options are negotiated
timeout_time = time.time() + self._network_timeout
while time.time() < timeout_time:
time.sleep(0.05) # prevent 100% CPU load
if sum(o.active for o in mandadory_options) == sum(o.state != INACTIVE for o in mandadory_options):
break
else:
raise SerialException("Remote does not seem to support RFC2217 or BINARY mode %r" % mandadory_options)
if self.logger:
self.logger.info("Negotiated options: %s" % self._telnet_options)
# fine, go on, set RFC 2271 specific things
self._reconfigure_port()
# all things set up get, now a clean start
if not self._dsrdtr:
self._update_dtr_state()
if not self._rtscts:
self._update_rts_state()
self.reset_input_buffer()
self.reset_output_buffer()
except:
self.close()
raise
def _reconfigure_port(self):
"""Set communication parameters on opened port."""
if self._socket is None:
raise SerialException("Can only operate on open ports")
# if self._timeout != 0 and self._interCharTimeout is not None:
# XXX
if self._write_timeout is not None:
raise NotImplementedError('write_timeout is currently not supported')
# XXX
# Setup the connection
# to get good performance, all parameter changes are sent first...
if not 0 < self._baudrate < 2**32:
raise ValueError("invalid baudrate: %r" % (self._baudrate))
self._rfc2217_port_settings['baudrate'].set(struct.pack(b'!I', self._baudrate))
self._rfc2217_port_settings['datasize'].set(struct.pack(b'!B', self._bytesize))
self._rfc2217_port_settings['parity'].set(struct.pack(b'!B', RFC2217_PARITY_MAP[self._parity]))
self._rfc2217_port_settings['stopsize'].set(struct.pack(b'!B', RFC2217_STOPBIT_MAP[self._stopbits]))
# and now wait until parameters are active
items = self._rfc2217_port_settings.values()
if self.logger:
self.logger.debug("Negotiating settings: %s" % (items,))
timeout_time = time.time() + self._network_timeout
while time.time() < timeout_time:
time.sleep(0.05) # prevent 100% CPU load
if sum(o.active for o in items) == len(items):
break
else:
raise SerialException("Remote does not accept parameter change (RFC2217): %r" % items)
if self.logger:
self.logger.info("Negotiated settings: %s" % (items,))
if self._rtscts and self._xonxoff:
raise ValueError('xonxoff and rtscts together are not supported')
elif self._rtscts:
self.rfc2217SetControl(SET_CONTROL_USE_HW_FLOW_CONTROL)
elif self._xonxoff:
self.rfc2217SetControl(SET_CONTROL_USE_SW_FLOW_CONTROL)
else:
self.rfc2217SetControl(SET_CONTROL_USE_NO_FLOW_CONTROL)
def close(self):
"""Close port"""
self.is_open = False
if self._socket:
try:
self._socket.shutdown(socket.SHUT_RDWR)
self._socket.close()
except:
# ignore errors.
pass
if self._thread:
self._thread.join(7) # XXX more than socket timeout
self._thread = None
# in case of quick reconnects, give the server some time
time.sleep(0.3)
self._socket = None
def from_url(self, url):
"""extract host and port from an URL string"""
parts = urlparse.urlsplit(url)
if parts.scheme != "rfc2217":
raise SerialException('expected a string in the form "rfc2217://<host>:<port>[?option[&option...]]": not starting with rfc2217:// (%r)' % (parts.scheme,))
try:
# process options now, directly altering self
for option, values in urlparse.parse_qs(parts.query, True).items():
if option == 'logging':
logging.basicConfig() # XXX is that good to call it here?
self.logger = logging.getLogger('pySerial.rfc2217')
self.logger.setLevel(LOGGER_LEVELS[values[0]])
self.logger.debug('enabled logging')
elif option == 'ign_set_control':
self._ignore_set_control_answer = True
elif option == 'poll_modem':
self._poll_modem_state = True
elif option == 'timeout':
self._network_timeout = float(values[0])
else:
raise ValueError('unknown option: %r' % (option,))
# get host and port
host, port = parts.hostname, parts.port
if not 0 <= port < 65536:
raise ValueError("port not in range 0...65535")
except ValueError as e:
raise SerialException('expected a string in the form "rfc2217://<host>:<port>[?option[&option...]]": %s' % e)
return (host, port)
# - - - - - - - - - - - - - - - - - - - - - - - -
@property
def in_waiting(self):
"""Return the number of bytes currently in the input buffer."""
if not self.is_open:
raise portNotOpenError
return self._read_buffer.qsize()
def read(self, size=1):
"""\
Read size bytes from the serial port. If a timeout is set it may
return less characters as requested. With no timeout it will block
until the requested number of bytes is read.
"""
if not self.is_open:
raise portNotOpenError
data = bytearray()
try:
while len(data) < size:
if self._thread is None:
raise SerialException('connection failed (reader thread died)')
data += self._read_buffer.get(True, self._timeout)
except Queue.Empty: # -> timeout
pass
return bytes(data)
def write(self, data):
"""\
Output the given byte string over the serial port. Can block if the
connection is blocked. May raise SerialException if the connection is
closed.
"""
if not self.is_open:
raise portNotOpenError
with self._write_lock:
try:
self._socket.sendall(to_bytes(data).replace(IAC, IAC_DOUBLED))
except socket.error as e:
raise SerialException("connection failed (socket error): %s" % (e,))
return len(data)
def reset_input_buffer(self):
"""Clear input buffer, discarding all that is in the buffer."""
if not self.is_open:
raise portNotOpenError
self.rfc2217SendPurge(PURGE_RECEIVE_BUFFER)
# empty read buffer
while self._read_buffer.qsize():
self._read_buffer.get(False)
def reset_output_buffer(self):
"""\
Clear output buffer, aborting the current output and
discarding all that is in the buffer.
"""
if not self.is_open:
raise portNotOpenError
self.rfc2217SendPurge(PURGE_TRANSMIT_BUFFER)
def _update_break_state(self):
"""\
Set break: Controls TXD. When active, to transmitting is
possible.
"""
if not self.is_open:
raise portNotOpenError
if self.logger:
self.logger.info('set BREAK to %s' % ('active' if self._break_state else 'inactive'))
if self._break_state:
self.rfc2217SetControl(SET_CONTROL_BREAK_ON)
else:
self.rfc2217SetControl(SET_CONTROL_BREAK_OFF)
def _update_rts_state(self):
"""Set terminal status line: Request To Send."""
if not self.is_open:
raise portNotOpenError
if self.logger:
self.logger.info('set RTS to %s' % ('active' if self._rts_state else 'inactive'))
if self._rts_state:
self.rfc2217SetControl(SET_CONTROL_RTS_ON)
else:
self.rfc2217SetControl(SET_CONTROL_RTS_OFF)
def _update_dtr_state(self, level=True):
"""Set terminal status line: Data Terminal Ready."""
if not self.is_open:
raise portNotOpenError
if self.logger:
self.logger.info('set DTR to %s' % ('active' if self._dtr_state else 'inactive'))
if self._dtr_state:
self.rfc2217SetControl(SET_CONTROL_DTR_ON)
else:
self.rfc2217SetControl(SET_CONTROL_DTR_OFF)
@property
def cts(self):
"""Read terminal status line: Clear To Send."""
if not self.is_open:
raise portNotOpenError
return bool(self.getModemState() & MODEMSTATE_MASK_CTS)
@property
def dsr(self):
"""Read terminal status line: Data Set Ready."""
if not self.is_open:
raise portNotOpenError
return bool(self.getModemState() & MODEMSTATE_MASK_DSR)
@property
def ri(self):
"""Read terminal status line: Ring Indicator."""
if not self.is_open:
raise portNotOpenError
return bool(self.getModemState() & MODEMSTATE_MASK_RI)
@property
def cd(self):
"""Read terminal status line: Carrier Detect."""
if not self.is_open:
raise portNotOpenError
return bool(self.getModemState() & MODEMSTATE_MASK_CD)
# - - - platform specific - - -
# None so far
# - - - RFC2217 specific - - -
def _telnetReadLoop(self):
"""Read loop for the socket."""
mode = M_NORMAL
suboption = None
try:
while self.is_open:
try:
data = self._socket.recv(1024)
except socket.timeout:
# just need to get out of recv form time to time to check if
# still alive
continue
except socket.error as e:
# connection fails -> terminate loop
if self.logger:
self.logger.debug("socket error in reader thread: %s" % (e,))
break
if not data:
break # lost connection
for byte in iterbytes(data):
if mode == M_NORMAL:
# interpret as command or as data
if byte == IAC:
mode = M_IAC_SEEN
else:
# store data in read buffer or sub option buffer
# depending on state
if suboption is not None:
suboption += byte
else:
self._read_buffer.put(byte)
elif mode == M_IAC_SEEN:
if byte == IAC:
# interpret as command doubled -> insert character
# itself
if suboption is not None:
suboption += IAC
else:
self._read_buffer.put(IAC)
mode = M_NORMAL
elif byte == SB:
# sub option start
suboption = bytearray()
mode = M_NORMAL
elif byte == SE:
# sub option end -> process it now
self._telnetProcessSubnegotiation(bytes(suboption))
suboption = None
mode = M_NORMAL
elif byte in (DO, DONT, WILL, WONT):
# negotiation
telnet_command = byte
mode = M_NEGOTIATE
else:
# other telnet commands
self._telnetProcessCommand(byte)
mode = M_NORMAL
elif mode == M_NEGOTIATE: # DO, DONT, WILL, WONT was received, option now following
self._telnetNegotiateOption(telnet_command, byte)
mode = M_NORMAL
finally:
self._thread = None
if self.logger:
self.logger.debug("read thread terminated")
# - incoming telnet commands and options
def _telnetProcessCommand(self, command):
"""Process commands other than DO, DONT, WILL, WONT."""
# Currently none. RFC2217 only uses negotiation and subnegotiation.
if self.logger:
self.logger.warning("ignoring Telnet command: %r" % (command,))
def _telnetNegotiateOption(self, command, option):
"""Process incoming DO, DONT, WILL, WONT."""
# check our registered telnet options and forward command to them
# they know themselves if they have to answer or not
known = False
for item in self._telnet_options:
# can have more than one match! as some options are duplicated for
# 'us' and 'them'
if item.option == option:
item.process_incoming(command)
known = True
if not known:
# handle unknown options
# only answer to positive requests and deny them
if command == WILL or command == DO:
self.telnetSendOption((DONT if command == WILL else WONT), option)
if self.logger:
self.logger.warning("rejected Telnet option: %r" % (option,))
def _telnetProcessSubnegotiation(self, suboption):
"""Process subnegotiation, the data between IAC SB and IAC SE."""
if suboption[0:1] == COM_PORT_OPTION:
if suboption[1:2] == SERVER_NOTIFY_LINESTATE and len(suboption) >= 3:
self._linestate = ord(suboption[2:3]) # ensure it is a number
if self.logger:
self.logger.info("NOTIFY_LINESTATE: %s" % self._linestate)
elif suboption[1:2] == SERVER_NOTIFY_MODEMSTATE and len(suboption) >= 3:
self._modemstate = ord(suboption[2:3]) # ensure it is a number
if self.logger:
self.logger.info("NOTIFY_MODEMSTATE: %s" % self._modemstate)
# update time when we think that a poll would make sense
self._modemstate_expires = time.time() + 0.3
elif suboption[1:2] == FLOWCONTROL_SUSPEND:
self._remote_suspend_flow = True
elif suboption[1:2] == FLOWCONTROL_RESUME:
self._remote_suspend_flow = False
else:
for item in self._rfc2217_options.values():
if item.ack_option == suboption[1:2]:
#~ print "processing COM_PORT_OPTION: %r" % list(suboption[1:])
item.checkAnswer(bytes(suboption[2:]))
break
else:
if self.logger:
self.logger.warning("ignoring COM_PORT_OPTION: %r" % (suboption,))
else:
if self.logger:
self.logger.warning("ignoring subnegotiation: %r" % (suboption,))
# - outgoing telnet commands and options
def _internal_raw_write(self, data):
"""internal socket write with no data escaping. used to send telnet stuff."""
with self._write_lock:
self._socket.sendall(data)
def telnetSendOption(self, action, option):
"""Send DO, DONT, WILL, WONT."""
self._internal_raw_write(to_bytes([IAC, action, option]))
def rfc2217SendSubnegotiation(self, option, value=b''):
"""Subnegotiation of RFC2217 parameters."""
value = value.replace(IAC, IAC_DOUBLED)
self._internal_raw_write(to_bytes([IAC, SB, COM_PORT_OPTION, option] + list(value) + [IAC, SE]))
def rfc2217SendPurge(self, value):
item = self._rfc2217_options['purge']
item.set(value) # transmit desired purge type
item.wait(self._network_timeout) # wait for acknowledge from the server
def rfc2217SetControl(self, value):
item = self._rfc2217_options['control']
item.set(value) # transmit desired control type
if self._ignore_set_control_answer:
# answers are ignored when option is set. compatibility mode for
# servers that answer, but not the expected one... (or no answer
# at all) i.e. sredird
time.sleep(0.1) # this helps getting the unit tests passed
else:
item.wait(self._network_timeout) # wait for acknowledge from the server
def rfc2217FlowServerReady(self):
"""\
check if server is ready to receive data. block for some time when
not.
"""
#~ if self._remote_suspend_flow:
#~ wait---
def getModemState(self):
"""\
get last modem state (cached value. If value is "old", request a new
one. This cache helps that we don't issue to many requests when e.g. all
status lines, one after the other is queried by the user (getCTS, getDSR
etc.)
"""
# active modem state polling enabled? is the value fresh enough?
if self._poll_modem_state and self._modemstate_expires < time.time():
if self.logger:
self.logger.debug('polling modem state')
# when it is older, request an update
self.rfc2217SendSubnegotiation(NOTIFY_MODEMSTATE)
timeout_time = time.time() + self._network_timeout
while time.time() < timeout_time:
time.sleep(0.05) # prevent 100% CPU load
# when expiration time is updated, it means that there is a new
# value
if self._modemstate_expires > time.time():
break
else:
if self.logger:
self.logger.warning('poll for modem state failed')
# even when there is a timeout, do not generate an error just
# return the last known value. this way we can support buggy
# servers that do not respond to polls, but send automatic
# updates.
if self._modemstate is not None:
if self.logger:
self.logger.debug('using cached modem state')
return self._modemstate
else:
# never received a notification from the server
raise SerialException("remote sends no NOTIFY_MODEMSTATE")
#############################################################################
# The following is code that helps implementing an RFC 2217 server.
class PortManager(object):
"""\
This class manages the state of Telnet and RFC 2217. It needs a serial
instance and a connection to work with. Connection is expected to implement
a (thread safe) write function, that writes the string to the network.
"""
def __init__(self, serial_port, connection, logger=None):
self.serial = serial_port
self.connection = connection
self.logger = logger
self._client_is_rfc2217 = False
# filter state machine
self.mode = M_NORMAL
self.suboption = None
self.telnet_command = None
# states for modem/line control events
self.modemstate_mask = 255
self.last_modemstate = None
self.linstate_mask = 0
# all supported telnet options
self._telnet_options = [
TelnetOption(self, 'ECHO', ECHO, WILL, WONT, DO, DONT, REQUESTED),
TelnetOption(self, 'we-SGA', SGA, WILL, WONT, DO, DONT, REQUESTED),
TelnetOption(self, 'they-SGA', SGA, DO, DONT, WILL, WONT, INACTIVE),
TelnetOption(self, 'we-BINARY', BINARY, WILL, WONT, DO, DONT, INACTIVE),
TelnetOption(self, 'they-BINARY', BINARY, DO, DONT, WILL, WONT, REQUESTED),
TelnetOption(self, 'we-RFC2217', COM_PORT_OPTION, WILL, WONT, DO, DONT, REQUESTED, self._client_ok),
TelnetOption(self, 'they-RFC2217', COM_PORT_OPTION, DO, DONT, WILL, WONT, INACTIVE, self._client_ok),
]
# negotiate Telnet/RFC2217 -> send initial requests
if self.logger:
self.logger.debug("requesting initial Telnet/RFC 2217 options")
for option in self._telnet_options:
if option.state is REQUESTED:
self.telnetSendOption(option.send_yes, option.option)
# issue 1st modem state notification
def _client_ok(self):
"""\
callback of telnet option. It gets called when option is activated.
This one here is used to detect when the client agrees on RFC 2217. A
flag is set so that other functions like check_modem_lines know if the
client is OK.
"""
# The callback is used for we and they so if one party agrees, we're
# already happy. it seems not all servers do the negotiation correctly
# and i guess there are incorrect clients too.. so be happy if client
# answers one or the other positively.
self._client_is_rfc2217 = True
if self.logger:
self.logger.info("client accepts RFC 2217")
# this is to ensure that the client gets a notification, even if there
# was no change
self.check_modem_lines(force_notification=True)
# - outgoing telnet commands and options
def telnetSendOption(self, action, option):
"""Send DO, DONT, WILL, WONT."""
self.connection.write(to_bytes([IAC, action, option]))
def rfc2217SendSubnegotiation(self, option, value=b''):
"""Subnegotiation of RFC 2217 parameters."""
value = value.replace(IAC, IAC_DOUBLED)
self.connection.write(to_bytes([IAC, SB, COM_PORT_OPTION, option] + list(value) + [IAC, SE]))
# - check modem lines, needs to be called periodically from user to
# establish polling
def check_modem_lines(self, force_notification=False):
modemstate = (
(self.serial.getCTS() and MODEMSTATE_MASK_CTS) |
(self.serial.getDSR() and MODEMSTATE_MASK_DSR) |
(self.serial.getRI() and MODEMSTATE_MASK_RI) |
(self.serial.getCD() and MODEMSTATE_MASK_CD))
# check what has changed
deltas = modemstate ^ (self.last_modemstate or 0) # when last is None -> 0
if deltas & MODEMSTATE_MASK_CTS:
modemstate |= MODEMSTATE_MASK_CTS_CHANGE
if deltas & MODEMSTATE_MASK_DSR:
modemstate |= MODEMSTATE_MASK_DSR_CHANGE
if deltas & MODEMSTATE_MASK_RI:
modemstate |= MODEMSTATE_MASK_RI_CHANGE
if deltas & MODEMSTATE_MASK_CD:
modemstate |= MODEMSTATE_MASK_CD_CHANGE
# if new state is different and the mask allows this change, send
# notification. suppress notifications when client is not rfc2217
if modemstate != self.last_modemstate or force_notification:
if (self._client_is_rfc2217 and (modemstate & self.modemstate_mask)) or force_notification:
self.rfc2217SendSubnegotiation(
SERVER_NOTIFY_MODEMSTATE,
to_bytes([modemstate & self.modemstate_mask])
)
if self.logger:
self.logger.info("NOTIFY_MODEMSTATE: %s" % (modemstate,))
# save last state, but forget about deltas.
# otherwise it would also notify about changing deltas which is
# probably not very useful
self.last_modemstate = modemstate & 0xf0
# - outgoing data escaping
def escape(self, data):
"""\
This generator function is for the user. All outgoing data has to be
properly escaped, so that no IAC character in the data stream messes up
the Telnet state machine in the server.
socket.sendall(escape(data))
"""
for byte in iterbytes(data):
if byte == IAC:
yield IAC
yield IAC
else:
yield byte
# - incoming data filter
def filter(self, data):
"""\
Handle a bunch of incoming bytes. This is a generator. It will yield
all characters not of interest for Telnet/RFC 2217.
The idea is that the reader thread pushes data from the socket through
this filter:
for byte in filter(socket.recv(1024)):
# do things like CR/LF conversion/whatever
# and write data to the serial port
serial.write(byte)
(socket error handling code left as exercise for the reader)
"""
for byte in iterbytes(data):
if self.mode == M_NORMAL:
# interpret as command or as data
if byte == IAC:
self.mode = M_IAC_SEEN
else:
# store data in sub option buffer or pass it to our
# consumer depending on state
if self.suboption is not None:
self.suboption += byte
else:
yield byte
elif self.mode == M_IAC_SEEN:
if byte == IAC:
# interpret as command doubled -> insert character
# itself
if self.suboption is not None:
self.suboption += byte
else:
yield byte
self.mode = M_NORMAL
elif byte == SB:
# sub option start
self.suboption = bytearray()
self.mode = M_NORMAL
elif byte == SE:
# sub option end -> process it now
self._telnetProcessSubnegotiation(bytes(self.suboption))
self.suboption = None
self.mode = M_NORMAL
elif byte in (DO, DONT, WILL, WONT):
# negotiation
self.telnet_command = byte
self.mode = M_NEGOTIATE
else:
# other telnet commands
self._telnetProcessCommand(byte)
self.mode = M_NORMAL
elif self.mode == M_NEGOTIATE: # DO, DONT, WILL, WONT was received, option now following
self._telnetNegotiateOption(self.telnet_command, byte)
self.mode = M_NORMAL
# - incoming telnet commands and options
def _telnetProcessCommand(self, command):
"""Process commands other than DO, DONT, WILL, WONT."""
# Currently none. RFC2217 only uses negotiation and subnegotiation.
if self.logger:
self.logger.warning("ignoring Telnet command: %r" % (command,))
def _telnetNegotiateOption(self, command, option):
"""Process incoming DO, DONT, WILL, WONT."""
# check our registered telnet options and forward command to them
# they know themselves if they have to answer or not
known = False
for item in self._telnet_options:
# can have more than one match! as some options are duplicated for
# 'us' and 'them'
if item.option == option:
item.process_incoming(command)
known = True
if not known:
# handle unknown options
# only answer to positive requests and deny them
if command == WILL or command == DO:
self.telnetSendOption((DONT if command == WILL else WONT), option)
if self.logger:
self.logger.warning("rejected Telnet option: %r" % (option,))
def _telnetProcessSubnegotiation(self, suboption):
"""Process subnegotiation, the data between IAC SB and IAC SE."""
if suboption[0:1] == COM_PORT_OPTION:
if self.logger:
self.logger.debug('received COM_PORT_OPTION: %r' % (suboption,))
if suboption[1:2] == SET_BAUDRATE:
backup = self.serial.baudrate
try:
(baudrate,) = struct.unpack(b"!I", suboption[2:6])
if baudrate != 0:
self.serial.baudrate = baudrate
except ValueError as e:
if self.logger:
self.logger.error("failed to set baud rate: %s" % (e,))
self.serial.baudrate = backup
else:
if self.logger:
self.logger.info("%s baud rate: %s" % ('set' if baudrate else 'get', self.serial.baudrate))
self.rfc2217SendSubnegotiation(SERVER_SET_BAUDRATE, struct.pack(b"!I", self.serial.baudrate))
elif suboption[1:2] == SET_DATASIZE:
backup = self.serial.bytesize
try:
(datasize,) = struct.unpack(b"!B", suboption[2:3])
if datasize != 0:
self.serial.bytesize = datasize
except ValueError as e:
if self.logger:
self.logger.error("failed to set data size: %s" % (e,))
self.serial.bytesize = backup
else:
if self.logger:
self.logger.info("%s data size: %s" % ('set' if datasize else 'get', self.serial.bytesize))
self.rfc2217SendSubnegotiation(SERVER_SET_DATASIZE, struct.pack(b"!B", self.serial.bytesize))
elif suboption[1:2] == SET_PARITY:
backup = self.serial.parity
try:
parity = struct.unpack(b"!B", suboption[2:3])[0]
if parity != 0:
self.serial.parity = RFC2217_REVERSE_PARITY_MAP[parity]
except ValueError as e:
if self.logger:
self.logger.error("failed to set parity: %s" % (e,))
self.serial.parity = backup
else:
if self.logger:
self.logger.info("%s parity: %s" % ('set' if parity else 'get', self.serial.parity))
self.rfc2217SendSubnegotiation(
SERVER_SET_PARITY,
struct.pack(b"!B", RFC2217_PARITY_MAP[self.serial.parity])
)
elif suboption[1:2] == SET_STOPSIZE:
backup = self.serial.stopbits
try:
stopbits = struct.unpack(b"!B", suboption[2:3])[0]
if stopbits != 0:
self.serial.stopbits = RFC2217_REVERSE_STOPBIT_MAP[stopbits]
except ValueError as e:
if self.logger:
self.logger.error("failed to set stop bits: %s" % (e,))
self.serial.stopbits = backup
else:
if self.logger:
self.logger.info("%s stop bits: %s" % ('set' if stopbits else 'get', self.serial.stopbits))
self.rfc2217SendSubnegotiation(
SERVER_SET_STOPSIZE,
struct.pack(b"!B", RFC2217_STOPBIT_MAP[self.serial.stopbits])
)
elif suboption[1:2] == SET_CONTROL:
if suboption[2:3] == SET_CONTROL_REQ_FLOW_SETTING:
if self.serial.xonxoff:
self.rfc2217SendSubnegotiation(SERVER_SET_CONTROL, SET_CONTROL_USE_SW_FLOW_CONTROL)
elif self.serial.rtscts:
self.rfc2217SendSubnegotiation(SERVER_SET_CONTROL, SET_CONTROL_USE_HW_FLOW_CONTROL)
else:
self.rfc2217SendSubnegotiation(SERVER_SET_CONTROL, SET_CONTROL_USE_NO_FLOW_CONTROL)
elif suboption[2:3] == SET_CONTROL_USE_NO_FLOW_CONTROL:
self.serial.xonxoff = False
self.serial.rtscts = False
if self.logger:
self.logger.info("changed flow control to None")
self.rfc2217SendSubnegotiation(SERVER_SET_CONTROL, SET_CONTROL_USE_NO_FLOW_CONTROL)
elif suboption[2:3] == SET_CONTROL_USE_SW_FLOW_CONTROL:
self.serial.xonxoff = True
if self.logger:
self.logger.info("changed flow control to XON/XOFF")
self.rfc2217SendSubnegotiation(SERVER_SET_CONTROL, SET_CONTROL_USE_SW_FLOW_CONTROL)
elif suboption[2:3] == SET_CONTROL_USE_HW_FLOW_CONTROL:
self.serial.rtscts = True
if self.logger:
self.logger.info("changed flow control to RTS/CTS")
self.rfc2217SendSubnegotiation(SERVER_SET_CONTROL, SET_CONTROL_USE_HW_FLOW_CONTROL)
elif suboption[2:3] == SET_CONTROL_REQ_BREAK_STATE:
if self.logger:
self.logger.warning("requested break state - not implemented")
pass # XXX needs cached value
elif suboption[2:3] == SET_CONTROL_BREAK_ON:
self.serial.setBreak(True)
if self.logger:
self.logger.info("changed BREAK to active")
self.rfc2217SendSubnegotiation(SERVER_SET_CONTROL, SET_CONTROL_BREAK_ON)
elif suboption[2:3] == SET_CONTROL_BREAK_OFF:
self.serial.setBreak(False)
if self.logger:
self.logger.info("changed BREAK to inactive")
self.rfc2217SendSubnegotiation(SERVER_SET_CONTROL, SET_CONTROL_BREAK_OFF)
elif suboption[2:3] == SET_CONTROL_REQ_DTR:
if self.logger:
self.logger.warning("requested DTR state - not implemented")
pass # XXX needs cached value
elif suboption[2:3] == SET_CONTROL_DTR_ON:
self.serial.setDTR(True)
if self.logger:
self.logger.info("changed DTR to active")
self.rfc2217SendSubnegotiation(SERVER_SET_CONTROL, SET_CONTROL_DTR_ON)
elif suboption[2:3] == SET_CONTROL_DTR_OFF:
self.serial.setDTR(False)
if self.logger:
self.logger.info("changed DTR to inactive")
self.rfc2217SendSubnegotiation(SERVER_SET_CONTROL, SET_CONTROL_DTR_OFF)
elif suboption[2:3] == SET_CONTROL_REQ_RTS:
if self.logger:
self.logger.warning("requested RTS state - not implemented")
pass # XXX needs cached value
#~ self.rfc2217SendSubnegotiation(SERVER_SET_CONTROL, SET_CONTROL_RTS_ON)
elif suboption[2:3] == SET_CONTROL_RTS_ON:
self.serial.setRTS(True)
if self.logger:
self.logger.info("changed RTS to active")
self.rfc2217SendSubnegotiation(SERVER_SET_CONTROL, SET_CONTROL_RTS_ON)
elif suboption[2:3] == SET_CONTROL_RTS_OFF:
self.serial.setRTS(False)
if self.logger:
self.logger.info("changed RTS to inactive")
self.rfc2217SendSubnegotiation(SERVER_SET_CONTROL, SET_CONTROL_RTS_OFF)
#~ elif suboption[2:3] == SET_CONTROL_REQ_FLOW_SETTING_IN:
#~ elif suboption[2:3] == SET_CONTROL_USE_NO_FLOW_CONTROL_IN:
#~ elif suboption[2:3] == SET_CONTROL_USE_SW_FLOW_CONTOL_IN:
#~ elif suboption[2:3] == SET_CONTROL_USE_HW_FLOW_CONTOL_IN:
#~ elif suboption[2:3] == SET_CONTROL_USE_DCD_FLOW_CONTROL:
#~ elif suboption[2:3] == SET_CONTROL_USE_DTR_FLOW_CONTROL:
#~ elif suboption[2:3] == SET_CONTROL_USE_DSR_FLOW_CONTROL:
elif suboption[1:2] == NOTIFY_LINESTATE:
# client polls for current state
self.rfc2217SendSubnegotiation(
SERVER_NOTIFY_LINESTATE,
to_bytes([0])) # sorry, nothing like that implemented
elif suboption[1:2] == NOTIFY_MODEMSTATE:
if self.logger:
self.logger.info("request for modem state")
# client polls for current state
self.check_modem_lines(force_notification=True)
elif suboption[1:2] == FLOWCONTROL_SUSPEND:
if self.logger:
self.logger.info("suspend")
self._remote_suspend_flow = True
elif suboption[1:2] == FLOWCONTROL_RESUME:
if self.logger:
self.logger.info("resume")
self._remote_suspend_flow = False
elif suboption[1:2] == SET_LINESTATE_MASK:
self.linstate_mask = ord(suboption[2:3]) # ensure it is a number
if self.logger:
self.logger.info("line state mask: 0x%02x" % (self.linstate_mask,))
elif suboption[1:2] == SET_MODEMSTATE_MASK:
self.modemstate_mask = ord(suboption[2:3]) # ensure it is a number
if self.logger:
self.logger.info("modem state mask: 0x%02x" % (self.modemstate_mask,))
elif suboption[1:2] == PURGE_DATA:
if suboption[2:3] == PURGE_RECEIVE_BUFFER:
self.serial.reset_input_buffer()
if self.logger:
self.logger.info("purge in")
self.rfc2217SendSubnegotiation(SERVER_PURGE_DATA, PURGE_RECEIVE_BUFFER)
elif suboption[2:3] == PURGE_TRANSMIT_BUFFER:
self.serial.reset_output_buffer()
if self.logger:
self.logger.info("purge out")
self.rfc2217SendSubnegotiation(SERVER_PURGE_DATA, PURGE_TRANSMIT_BUFFER)
elif suboption[2:3] == PURGE_BOTH_BUFFERS:
self.serial.reset_input_buffer()
self.serial.reset_output_buffer()
if self.logger:
self.logger.info("purge both")
self.rfc2217SendSubnegotiation(SERVER_PURGE_DATA, PURGE_BOTH_BUFFERS)
else:
if self.logger:
self.logger.error("undefined PURGE_DATA: %r" % list(suboption[2:]))
else:
if self.logger:
self.logger.error("undefined COM_PORT_OPTION: %r" % list(suboption[1:]))
else:
if self.logger:
self.logger.warning("unknown subnegotiation: %r" % (suboption,))
# simple client test
if __name__ == '__main__':
import sys
s = Serial('rfc2217://localhost:7000', 115200)
sys.stdout.write('%s\n' % s)
sys.stdout.write("write...\n")
s.write(b"hello\n")
s.flush()
sys.stdout.write("read: %s\n" % s.read(5))
s.close()
