Files correlati : utilma verione di curl git-svn-id: svn://10.65.10.50/branches/R_10_00@24159 c028cbd2-c16b-5b4b-a496-9718f37d4682
		
			
				
	
	
		
			350 lines
		
	
	
		
			10 KiB
		
	
	
	
		
			Python
		
	
	
	
	
	
			
		
		
	
	
			350 lines
		
	
	
		
			10 KiB
		
	
	
	
		
			Python
		
	
	
	
	
	
#!/usr/bin/env python
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# -*- coding: utf-8 -*-
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#
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""" A telnet server which negotiates"""
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from __future__ import (absolute_import, division, print_function,
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                        unicode_literals)
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import argparse
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import os
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import sys
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import logging
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import struct
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try:  # Python 2
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    import SocketServer as socketserver
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except ImportError:  # Python 3
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    import socketserver
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log = logging.getLogger(__name__)
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HOST = "localhost"
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IDENT = "NTEL"
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# The strings that indicate the test framework is checking our aliveness
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VERIFIED_REQ = b"verifiedserver"
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VERIFIED_RSP = b"WE ROOLZ: {pid}"
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def telnetserver(options):
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    """
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    Starts up a TCP server with a telnet handler and serves DICT requests
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    forever.
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    """
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    if options.pidfile:
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        pid = os.getpid()
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        with open(options.pidfile, "w") as f:
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            f.write(b"{0}".format(pid))
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    local_bind = (HOST, options.port)
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    log.info("Listening on %s", local_bind)
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    # Need to set the allow_reuse on the class, not on the instance.
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    socketserver.TCPServer.allow_reuse_address = True
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    server = socketserver.TCPServer(local_bind, NegotiatingTelnetHandler)
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    server.serve_forever()
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    return ScriptRC.SUCCESS
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class NegotiatingTelnetHandler(socketserver.BaseRequestHandler):
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    """Handler class for Telnet connections.
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    """
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    def handle(self):
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        """
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        Negotiates options before reading data.
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        """
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        neg = Negotiator(self.request)
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        try:
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            # Send some initial negotiations.
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            neg.send_do("NEW_ENVIRON")
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            neg.send_will("NEW_ENVIRON")
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            neg.send_dont("NAWS")
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            neg.send_wont("NAWS")
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            # Get the data passed through the negotiator
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            data = neg.recv(1024)
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            log.debug("Incoming data: %r", data)
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            if VERIFIED_REQ in data:
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                log.debug("Received verification request from test framework")
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                response_data = VERIFIED_RSP.format(pid=os.getpid())
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            else:
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                log.debug("Received normal request - echoing back")
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                response_data = data.strip()
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            if response_data:
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                log.debug("Sending %r", response_data)
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                self.request.sendall(response_data)
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        except IOError:
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            log.exception("IOError hit during request")
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class Negotiator(object):
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    NO_NEG = 0
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    START_NEG = 1
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    WILL = 2
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    WONT = 3
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    DO = 4
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    DONT = 5
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    def __init__(self, tcp):
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        self.tcp = tcp
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        self.state = self.NO_NEG
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    def recv(self, bytes):
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        """
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        Read bytes from TCP, handling negotiation sequences
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        :param bytes: Number of bytes to read
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        :return: a buffer of bytes
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        """
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        buffer = bytearray()
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        # If we keep receiving negotiation sequences, we won't fill the buffer.
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        # Keep looping while we can, and until we have something to give back
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        # to the caller.
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        while len(buffer) == 0:
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            data = self.tcp.recv(bytes)
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            if not data:
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                # TCP failed to give us any data. Break out.
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                break
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            for byte in data:
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                byte_int = self.byte_to_int(byte)
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                if self.state == self.NO_NEG:
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                    self.no_neg(byte, byte_int, buffer)
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                elif self.state == self.START_NEG:
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                    self.start_neg(byte_int)
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                elif self.state in [self.WILL, self.WONT, self.DO, self.DONT]:
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                    self.handle_option(byte_int)
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                else:
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                    # Received an unexpected byte. Stop negotiations
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                    log.error("Unexpected byte %s in state %s",
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                              byte_int,
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                              self.state)
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                    self.state = self.NO_NEG
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        return buffer
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    def byte_to_int(self, byte):
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        return struct.unpack(b'B', byte)[0]
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    def no_neg(self, byte, byte_int, buffer):
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        # Not negotiating anything thus far. Check to see if we
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        # should.
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        if byte_int == NegTokens.IAC:
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            # Start negotiation
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            log.debug("Starting negotiation (IAC)")
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            self.state = self.START_NEG
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        else:
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            # Just append the incoming byte to the buffer
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            buffer.append(byte)
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    def start_neg(self, byte_int):
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        # In a negotiation.
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        log.debug("In negotiation (%s)",
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                  NegTokens.from_val(byte_int))
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        if byte_int == NegTokens.WILL:
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            # Client is confirming they are willing to do an option
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            log.debug("Client is willing")
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            self.state = self.WILL
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        elif byte_int == NegTokens.WONT:
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            # Client is confirming they are unwilling to do an
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            # option
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            log.debug("Client is unwilling")
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            self.state = self.WONT
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        elif byte_int == NegTokens.DO:
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            # Client is indicating they can do an option
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            log.debug("Client can do")
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            self.state = self.DO
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        elif byte_int == NegTokens.DONT:
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            # Client is indicating they can't do an option
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            log.debug("Client can't do")
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            self.state = self.DONT
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        else:
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            # Received an unexpected byte. Stop negotiations
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            log.error("Unexpected byte %s in state %s",
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                      byte_int,
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                      self.state)
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            self.state = self.NO_NEG
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    def handle_option(self, byte_int):
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        if byte_int in [NegOptions.BINARY,
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                        NegOptions.CHARSET,
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                        NegOptions.SUPPRESS_GO_AHEAD,
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                        NegOptions.NAWS,
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                        NegOptions.NEW_ENVIRON]:
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            log.debug("Option: %s", NegOptions.from_val(byte_int))
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            # No further negotiation of this option needed. Reset the state.
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            self.state = self.NO_NEG
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        else:
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            # Received an unexpected byte. Stop negotiations
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            log.error("Unexpected byte %s in state %s",
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                      byte_int,
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                      self.state)
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            self.state = self.NO_NEG
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    def send_message(self, message):
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        packed_message = self.pack(message)
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        self.tcp.sendall(packed_message)
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    def pack(self, arr):
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        return struct.pack(b'{0}B'.format(len(arr)), *arr)
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    def send_iac(self, arr):
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        message = [NegTokens.IAC]
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        message.extend(arr)
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        self.send_message(message)
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    def send_do(self, option_str):
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        log.debug("Sending DO %s", option_str)
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        self.send_iac([NegTokens.DO, NegOptions.to_val(option_str)])
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    def send_dont(self, option_str):
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        log.debug("Sending DONT %s", option_str)
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        self.send_iac([NegTokens.DONT, NegOptions.to_val(option_str)])
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    def send_will(self, option_str):
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        log.debug("Sending WILL %s", option_str)
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        self.send_iac([NegTokens.WILL, NegOptions.to_val(option_str)])
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    def send_wont(self, option_str):
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        log.debug("Sending WONT %s", option_str)
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        self.send_iac([NegTokens.WONT, NegOptions.to_val(option_str)])
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class NegBase(object):
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    @classmethod
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    def to_val(cls, name):
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        return getattr(cls, name)
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    @classmethod
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    def from_val(cls, val):
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        for k in cls.__dict__.keys():
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            if getattr(cls, k) == val:
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                return k
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        return "<unknown>"
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class NegTokens(NegBase):
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    # The start of a negotiation sequence
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    IAC = 255
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    # Confirm willingness to negotiate
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    WILL = 251
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    # Confirm unwillingness to negotiate
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    WONT = 252
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    # Indicate willingness to negotiate
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    DO = 253
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    # Indicate unwillingness to negotiate
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    DONT = 254
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    # The start of sub-negotiation options.
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    SB = 250
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    # The end of sub-negotiation options.
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    SE = 240
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class NegOptions(NegBase):
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    # Binary Transmission
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    BINARY = 0
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    # Suppress Go Ahead
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    SUPPRESS_GO_AHEAD = 3
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    # NAWS - width and height of client
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    NAWS = 31
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    # NEW-ENVIRON - environment variables on client
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    NEW_ENVIRON = 39
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    # Charset option
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    CHARSET = 42
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def get_options():
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    parser = argparse.ArgumentParser()
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    parser.add_argument("--port", action="store", default=9019,
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                        type=int, help="port to listen on")
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    parser.add_argument("--verbose", action="store", type=int, default=0,
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                        help="verbose output")
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    parser.add_argument("--pidfile", action="store",
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                        help="file name for the PID")
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    parser.add_argument("--logfile", action="store",
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                        help="file name for the log")
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    parser.add_argument("--srcdir", action="store", help="test directory")
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    parser.add_argument("--id", action="store", help="server ID")
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    parser.add_argument("--ipv4", action="store_true", default=0,
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                        help="IPv4 flag")
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    return parser.parse_args()
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def setup_logging(options):
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    """
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    Set up logging from the command line options
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    """
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    root_logger = logging.getLogger()
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    add_stdout = False
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    formatter = logging.Formatter("%(asctime)s %(levelname)-5.5s "
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                                  "[{ident}] %(message)s"
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                                  .format(ident=IDENT))
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    # Write out to a logfile
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    if options.logfile:
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        handler = logging.FileHandler(options.logfile, mode="w")
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        handler.setFormatter(formatter)
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        handler.setLevel(logging.DEBUG)
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        root_logger.addHandler(handler)
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    else:
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        # The logfile wasn't specified. Add a stdout logger.
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        add_stdout = True
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    if options.verbose:
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        # Add a stdout logger as well in verbose mode
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        root_logger.setLevel(logging.DEBUG)
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        add_stdout = True
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    else:
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        root_logger.setLevel(logging.INFO)
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    if add_stdout:
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        stdout_handler = logging.StreamHandler(sys.stdout)
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        stdout_handler.setFormatter(formatter)
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        stdout_handler.setLevel(logging.DEBUG)
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        root_logger.addHandler(stdout_handler)
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class ScriptRC(object):
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    """Enum for script return codes"""
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    SUCCESS = 0
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    FAILURE = 1
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    EXCEPTION = 2
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class ScriptException(Exception):
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    pass
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if __name__ == '__main__':
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    # Get the options from the user.
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    options = get_options()
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    # Setup logging using the user options
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    setup_logging(options)
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    # Run main script.
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    try:
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        rc = telnetserver(options)
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    except Exception as e:
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        log.exception(e)
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        rc = ScriptRC.EXCEPTION
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    log.info("Returning %d", rc)
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    sys.exit(rc)
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