| #!/usr/bin/env python |
| # -*- coding: utf-8 -*- |
| # |
| # Project ___| | | | _ \| | |
| # / __| | | | |_) | | |
| # | (__| |_| | _ <| |___ |
| # \___|\___/|_| \_\_____| |
| # |
| # Copyright (C) 2017 - 2020, Daniel Stenberg, <[email protected]>, et al. |
| # |
| # This software is licensed as described in the file COPYING, which |
| # you should have received as part of this distribution. The terms |
| # are also available at https://curl.se/docs/copyright.html. |
| # |
| # You may opt to use, copy, modify, merge, publish, distribute and/or sell |
| # copies of the Software, and permit persons to whom the Software is |
| # furnished to do so, under the terms of the COPYING file. |
| # |
| # This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY |
| # KIND, either express or implied. |
| # |
| """ A telnet server which negotiates""" |
| |
| from __future__ import (absolute_import, division, print_function, |
| unicode_literals) |
| |
| import argparse |
| import logging |
| import os |
| import sys |
| |
| from util import ClosingFileHandler |
| |
| if sys.version_info.major >= 3: |
| import socketserver |
| else: |
| import SocketServer as socketserver |
| |
| log = logging.getLogger(__name__) |
| HOST = "localhost" |
| IDENT = "NTEL" |
| |
| |
| # The strings that indicate the test framework is checking our aliveness |
| VERIFIED_REQ = "verifiedserver" |
| VERIFIED_RSP = "WE ROOLZ: {pid}" |
| |
| |
| def telnetserver(options): |
| """ |
| Starts up a TCP server with a telnet handler and serves DICT requests |
| forever. |
| """ |
| if options.pidfile: |
| pid = os.getpid() |
| # see tests/server/util.c function write_pidfile |
| if os.name == "nt": |
| pid += 65536 |
| with open(options.pidfile, "w") as f: |
| f.write(str(pid)) |
| |
| local_bind = (HOST, options.port) |
| log.info("Listening on %s", local_bind) |
| |
| # Need to set the allow_reuse on the class, not on the instance. |
| socketserver.TCPServer.allow_reuse_address = True |
| server = socketserver.TCPServer(local_bind, NegotiatingTelnetHandler) |
| server.serve_forever() |
| |
| return ScriptRC.SUCCESS |
| |
| |
| class NegotiatingTelnetHandler(socketserver.BaseRequestHandler): |
| """Handler class for Telnet connections. |
| |
| """ |
| def handle(self): |
| """ |
| Negotiates options before reading data. |
| """ |
| neg = Negotiator(self.request) |
| |
| try: |
| # Send some initial negotiations. |
| neg.send_do("NEW_ENVIRON") |
| neg.send_will("NEW_ENVIRON") |
| neg.send_dont("NAWS") |
| neg.send_wont("NAWS") |
| |
| # Get the data passed through the negotiator |
| data = neg.recv(1024) |
| log.debug("Incoming data: %r", data) |
| |
| if VERIFIED_REQ.encode('utf-8') in data: |
| log.debug("Received verification request from test framework") |
| pid = os.getpid() |
| # see tests/server/util.c function write_pidfile |
| if os.name == "nt": |
| pid += 65536 |
| response = VERIFIED_RSP.format(pid=pid) |
| response_data = response.encode('utf-8') |
| else: |
| log.debug("Received normal request - echoing back") |
| response_data = data.decode('utf-8').strip().encode('utf-8') |
| |
| if response_data: |
| log.debug("Sending %r", response_data) |
| self.request.sendall(response_data) |
| |
| except IOError: |
| log.exception("IOError hit during request") |
| |
| |
| class Negotiator(object): |
| NO_NEG = 0 |
| START_NEG = 1 |
| WILL = 2 |
| WONT = 3 |
| DO = 4 |
| DONT = 5 |
| |
| def __init__(self, tcp): |
| self.tcp = tcp |
| self.state = self.NO_NEG |
| |
| def recv(self, bytes): |
| """ |
| Read bytes from TCP, handling negotiation sequences |
| |
| :param bytes: Number of bytes to read |
| :return: a buffer of bytes |
| """ |
| buffer = bytearray() |
| |
| # If we keep receiving negotiation sequences, we won't fill the buffer. |
| # Keep looping while we can, and until we have something to give back |
| # to the caller. |
| while len(buffer) == 0: |
| data = self.tcp.recv(bytes) |
| if not data: |
| # TCP failed to give us any data. Break out. |
| break |
| |
| for byte_int in bytearray(data): |
| if self.state == self.NO_NEG: |
| self.no_neg(byte_int, buffer) |
| elif self.state == self.START_NEG: |
| self.start_neg(byte_int) |
| elif self.state in [self.WILL, self.WONT, self.DO, self.DONT]: |
| self.handle_option(byte_int) |
| else: |
| # Received an unexpected byte. Stop negotiations |
| log.error("Unexpected byte %s in state %s", |
| byte_int, |
| self.state) |
| self.state = self.NO_NEG |
| |
| return buffer |
| |
| def no_neg(self, byte_int, buffer): |
| # Not negotiating anything thus far. Check to see if we |
| # should. |
| if byte_int == NegTokens.IAC: |
| # Start negotiation |
| log.debug("Starting negotiation (IAC)") |
| self.state = self.START_NEG |
| else: |
| # Just append the incoming byte to the buffer |
| buffer.append(byte_int) |
| |
| def start_neg(self, byte_int): |
| # In a negotiation. |
| log.debug("In negotiation (%s)", |
| NegTokens.from_val(byte_int)) |
| |
| if byte_int == NegTokens.WILL: |
| # Client is confirming they are willing to do an option |
| log.debug("Client is willing") |
| self.state = self.WILL |
| elif byte_int == NegTokens.WONT: |
| # Client is confirming they are unwilling to do an |
| # option |
| log.debug("Client is unwilling") |
| self.state = self.WONT |
| elif byte_int == NegTokens.DO: |
| # Client is indicating they can do an option |
| log.debug("Client can do") |
| self.state = self.DO |
| elif byte_int == NegTokens.DONT: |
| # Client is indicating they can't do an option |
| log.debug("Client can't do") |
| self.state = self.DONT |
| else: |
| # Received an unexpected byte. Stop negotiations |
| log.error("Unexpected byte %s in state %s", |
| byte_int, |
| self.state) |
| self.state = self.NO_NEG |
| |
| def handle_option(self, byte_int): |
| if byte_int in [NegOptions.BINARY, |
| NegOptions.CHARSET, |
| NegOptions.SUPPRESS_GO_AHEAD, |
| NegOptions.NAWS, |
| NegOptions.NEW_ENVIRON]: |
| log.debug("Option: %s", NegOptions.from_val(byte_int)) |
| |
| # No further negotiation of this option needed. Reset the state. |
| self.state = self.NO_NEG |
| |
| else: |
| # Received an unexpected byte. Stop negotiations |
| log.error("Unexpected byte %s in state %s", |
| byte_int, |
| self.state) |
| self.state = self.NO_NEG |
| |
| def send_message(self, message_ints): |
| self.tcp.sendall(bytearray(message_ints)) |
| |
| def send_iac(self, arr): |
| message = [NegTokens.IAC] |
| message.extend(arr) |
| self.send_message(message) |
| |
| def send_do(self, option_str): |
| log.debug("Sending DO %s", option_str) |
| self.send_iac([NegTokens.DO, NegOptions.to_val(option_str)]) |
| |
| def send_dont(self, option_str): |
| log.debug("Sending DONT %s", option_str) |
| self.send_iac([NegTokens.DONT, NegOptions.to_val(option_str)]) |
| |
| def send_will(self, option_str): |
| log.debug("Sending WILL %s", option_str) |
| self.send_iac([NegTokens.WILL, NegOptions.to_val(option_str)]) |
| |
| def send_wont(self, option_str): |
| log.debug("Sending WONT %s", option_str) |
| self.send_iac([NegTokens.WONT, NegOptions.to_val(option_str)]) |
| |
| |
| class NegBase(object): |
| @classmethod |
| def to_val(cls, name): |
| return getattr(cls, name) |
| |
| @classmethod |
| def from_val(cls, val): |
| for k in cls.__dict__.keys(): |
| if getattr(cls, k) == val: |
| return k |
| |
| return "<unknown>" |
| |
| |
| class NegTokens(NegBase): |
| # The start of a negotiation sequence |
| IAC = 255 |
| # Confirm willingness to negotiate |
| WILL = 251 |
| # Confirm unwillingness to negotiate |
| WONT = 252 |
| # Indicate willingness to negotiate |
| DO = 253 |
| # Indicate unwillingness to negotiate |
| DONT = 254 |
| |
| # The start of sub-negotiation options. |
| SB = 250 |
| # The end of sub-negotiation options. |
| SE = 240 |
| |
| |
| class NegOptions(NegBase): |
| # Binary Transmission |
| BINARY = 0 |
| # Suppress Go Ahead |
| SUPPRESS_GO_AHEAD = 3 |
| # NAWS - width and height of client |
| NAWS = 31 |
| # NEW-ENVIRON - environment variables on client |
| NEW_ENVIRON = 39 |
| # Charset option |
| CHARSET = 42 |
| |
| |
| def get_options(): |
| parser = argparse.ArgumentParser() |
| |
| parser.add_argument("--port", action="store", default=9019, |
| type=int, help="port to listen on") |
| parser.add_argument("--verbose", action="store", type=int, default=0, |
| help="verbose output") |
| parser.add_argument("--pidfile", action="store", |
| help="file name for the PID") |
| parser.add_argument("--logfile", action="store", |
| help="file name for the log") |
| parser.add_argument("--srcdir", action="store", help="test directory") |
| parser.add_argument("--id", action="store", help="server ID") |
| parser.add_argument("--ipv4", action="store_true", default=0, |
| help="IPv4 flag") |
| |
| return parser.parse_args() |
| |
| |
| def setup_logging(options): |
| """ |
| Set up logging from the command line options |
| """ |
| root_logger = logging.getLogger() |
| add_stdout = False |
| |
| formatter = logging.Formatter("%(asctime)s %(levelname)-5.5s " |
| "[{ident}] %(message)s" |
| .format(ident=IDENT)) |
| |
| # Write out to a logfile |
| if options.logfile: |
| handler = ClosingFileHandler(options.logfile) |
| handler.setFormatter(formatter) |
| handler.setLevel(logging.DEBUG) |
| root_logger.addHandler(handler) |
| else: |
| # The logfile wasn't specified. Add a stdout logger. |
| add_stdout = True |
| |
| if options.verbose: |
| # Add a stdout logger as well in verbose mode |
| root_logger.setLevel(logging.DEBUG) |
| add_stdout = True |
| else: |
| root_logger.setLevel(logging.INFO) |
| |
| if add_stdout: |
| stdout_handler = logging.StreamHandler(sys.stdout) |
| stdout_handler.setFormatter(formatter) |
| stdout_handler.setLevel(logging.DEBUG) |
| root_logger.addHandler(stdout_handler) |
| |
| |
| class ScriptRC(object): |
| """Enum for script return codes""" |
| SUCCESS = 0 |
| FAILURE = 1 |
| EXCEPTION = 2 |
| |
| |
| class ScriptException(Exception): |
| pass |
| |
| |
| if __name__ == '__main__': |
| # Get the options from the user. |
| options = get_options() |
| |
| # Setup logging using the user options |
| setup_logging(options) |
| |
| # Run main script. |
| try: |
| rc = telnetserver(options) |
| except Exception as e: |
| log.exception(e) |
| rc = ScriptRC.EXCEPTION |
| |
| log.info("Returning %d", rc) |
| sys.exit(rc) |
