improve telnet option negotiation
diff --git a/pyserial/documentation/pyserial_api.rst b/pyserial/documentation/pyserial_api.rst
index 0e3f797..22e519c 100644
--- a/pyserial/documentation/pyserial_api.rst
+++ b/pyserial/documentation/pyserial_api.rst
@@ -500,7 +500,6 @@
- :rfc:`2217` flow control between client and server. (objects internal
buffer may eat all your memory when never read)
- - The telnet option negotiation may be done incorrectly.
.. versionadded:: 2.5
diff --git a/pyserial/serial/rfc2217.py b/pyserial/serial/rfc2217.py
index b12acb4..0b1b981 100644
--- a/pyserial/serial/rfc2217.py
+++ b/pyserial/serial/rfc2217.py
@@ -15,7 +15,6 @@
# severs). consider implementing a compatibility mode flag to make check
# conditional
# - write timeout not implemented at all
-# - telnet negotiation probably not correctly implemented
from serialutil import *
import time
@@ -171,6 +170,57 @@
WONT: (DONT, WONT),
}
+REQUESTED = 'REQUESTED'
+ACTIVE = 'ACTIVE'
+INACTIVE = 'INACTIVE'
+REALLY_INACTIVE = 'REALLY_INACTIVE'
+
+class TelnetOption(object):
+ """Manages one telnet option, keeps track of DO/DONT WILL/WONT"""
+ def __init__(self, name, option, send_yes, send_no, ack_yes, ack_no, initial_state):
+ 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
+
+ def __repr__(self):
+ return "%s:%s(%s)" % (self.name, self.active, self.state)
+
+ def process_incoming(self, command, send_option):
+ if command == self.ack_yes:
+ if self.state is REQUESTED:
+ self.state = ACTIVE
+ self.active = True
+ elif self.state is ACTIVE:
+ pass
+ elif self.state is INACTIVE:
+ self.state = ACTIVE
+ send_option(self.send_yes, self.option)
+ self.active = True
+ elif self.state is REALLY_INACTIVE:
+ send_option(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
+ send_option(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 RFC2217Serial(SerialBase):
"""Serial port implementation for RFC2217 remote serial ports"""
@@ -192,7 +242,20 @@
self._socket.settimeout(5)
self._read_buffer = Queue.Queue()
- self._telnet_negotiated_options = {}
+ # name the following separately so that, below, a check can be easily done
+ mandadory_options = [
+ TelnetOption('we-BINARY', BINARY, WILL, WONT, DO, DONT, INACTIVE),
+ TelnetOption('they-BINARY', BINARY, DO, DONT, WILL, WONT, INACTIVE),
+ TelnetOption('we-RFC2217', COM_PORT_OPTION, WILL, WONT, DO, DONT, REQUESTED),
+ TelnetOption('they-RFC2217', COM_PORT_OPTION, DO, DONT, WILL, WONT, REQUESTED),
+ ]
+ # all supported telnet options
+ self._telnet_options = [
+ TelnetOption('ECHO', ECHO, DO, DONT, WILL, WONT, INACTIVE),
+ TelnetOption('we-SGA', SGA, WILL, WONT, DO, DONT, REQUESTED),
+ TelnetOption('they-SGA', SGA, DO, DONT, WILL, WONT, REQUESTED),
+ ] + mandadory_options
+ # RFC2217 specific states
self._rfc2217_negotiated_options = {}
self._linestate = 0
self._modemstate = 0
@@ -202,14 +265,22 @@
self._thread.setName('pySerial RFC2217 reader thread for %s' % (self._port,))
self._thread.start()
- # negotiate Telnet/RFC2217
- self._negotiate_telnet_option(DO, BINARY)
- #~ self._negotiate_telnet_option(DONT, ECHO)
- if self._negotiate_telnet_option(DO, COM_PORT_OPTION) in (WILL, DO):
- raise SerialException("Remote does not seem to support RFC2217")
+ # negotiate Telnet/RFC2217 -> send initial requests
+ for option in self._telnet_options:
+ if option.state is REQUESTED:
+ self._telnet_send_option(option.send_yes, option.option)
+ # now wait until important options are negotiated
+ timeout_time = time.time() + 3
+ while time.time() < timeout_time:
+ if sum(o.active for o in mandadory_options) == len(mandadory_options): break
+ time.sleep(0.05) # prevent 100% CPU load
+ #~ print self._telnet_options
+ if sum(o.active for o in mandadory_options) != len(mandadory_options):
+ raise SerialException("Remote does not seem to support RFC2217 or BINARY mode")
# fine, go on, set RFC2271 specific things
self._reconfigurePort()
+
self._isOpen = True
if not self._rtscts:
self.setRTS(True)
@@ -450,9 +521,19 @@
#~ print "_telnet_process_command %r" % ord(command)
def _telnet_negotiate_option(self, command, option):
- """Process DO, DONT, WILL, WONT"""
- self._telnet_negotiated_options[option] = command
+ """Process incomming DO, DONT, WILL, WONT"""
#~ print "_telnet_negotiate_option %r %r" % ({DO:'DO', DONT:'DONT', WILL:'WILL', WONT:'WONT'}[command], ord(option))
+ known = False
+ for item in self._telnet_options:
+ if item.option == option:
+ item.process_incoming(command, send_option=self._telnet_send_option)
+ known = True
+ if not known:
+ # handle unknown options
+ # only answer to positive requests and deny them
+ if command == WILL or command == DO:
+ self._telnet_send_option((command == WILL and DONT or WONT), option)
+
def _telnet_process_suboption(self, suboption):
"""Process suboptions, the data between IAC SB and IAC SE"""
@@ -472,21 +553,10 @@
# - outgoing telnet commands and options
- def _negotiate_telnet_option(self, action, option):
+ def _telnet_send_option(self, action, option):
"""Send DO, DONT, WILL, WONT"""
- #~ print "_negotiate_telnet_option %r %r" % ({DO:'DO', DONT:'DONT', WILL:'WILL', WONT:'WONT'}[action], ord(option))
- #~ if option in self._telnet_negotiated_options and \
- #~ self._telnet_negotioted_options[option] in TELNET_ACTION_SUCCESS_MAP[action]:
- #~ print "_negotiate_telnet_option already in good state"
- #~ return
+ #~ print "_telnet_send_option %r %r" % ({DO:'DO', DONT:'DONT', WILL:'WILL', WONT:'WONT'}[action], ord(option))
self._socket.sendall(to_bytes([IAC, action, option]))
- for tries in range(10):
- if option in self._telnet_negotiated_options and \
- self._telnet_negotiated_options[option] in TELNET_ACTION_SUCCESS_MAP[action]:
- break
- time.sleep(0.1)
- else:
- raise SerialException("Timeout or server rejected telnet option %r" % (option,))
def _set_comport_option(self, option, value=[]):
"""Subnegotiation of RFC2217 parameters"""
