mirror of
https://github.com/GNS3/gns3-server
synced 2024-11-12 19:38:57 +00:00
282 lines
11 KiB
Python
282 lines
11 KiB
Python
# -*- coding: utf-8 -*-
|
||
#
|
||
# Copyright (C) 2014 GNS3 Technologies Inc.
|
||
#
|
||
# This program is free software: you can redistribute it and/or modify
|
||
# it under the terms of the GNU General Public License as published by
|
||
# the Free Software Foundation, either version 3 of the License, or
|
||
# (at your option) any later version.
|
||
#
|
||
# This program is distributed in the hope that it will be useful,
|
||
# but WITHOUT ANY WARRANTY; without even the implied warranty of
|
||
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
||
# GNU General Public License for more details.
|
||
#
|
||
# You should have received a copy of the GNU General Public License
|
||
# along with this program. If not, see <http://www.gnu.org/licenses/>.
|
||
|
||
import asyncio
|
||
import asyncio.subprocess
|
||
|
||
import logging
|
||
log = logging.getLogger(__name__)
|
||
|
||
# Mostly from https://code.google.com/p/miniboa/source/browse/trunk/miniboa/telnet.py
|
||
|
||
# Telnet Commands
|
||
SE = 240 # End of sub-negotiation parameters
|
||
NOP = 241 # No operation
|
||
DATMK = 242 # Data stream portion of a sync.
|
||
BREAK = 243 # NVT Character BRK
|
||
IP = 244 # Interrupt Process
|
||
AO = 245 # Abort Output
|
||
AYT = 246 # Are you there
|
||
EC = 247 # Erase Character
|
||
EL = 248 # Erase Line
|
||
GA = 249 # The Go Ahead Signal
|
||
SB = 250 # Sub-option to follow
|
||
WILL = 251 # Will; request or confirm option begin
|
||
WONT = 252 # Wont; deny option request
|
||
DO = 253 # Do = Request or confirm remote option
|
||
DONT = 254 # Don't = Demand or confirm option halt
|
||
IAC = 255 # Interpret as Command
|
||
SEND = 1 # Sub-process negotiation SEND command
|
||
IS = 0 # Sub-process negotiation IS command
|
||
|
||
# Telnet Options
|
||
BINARY = 0 # Transmit Binary
|
||
ECHO = 1 # Echo characters back to sender
|
||
RECON = 2 # Reconnection
|
||
SGA = 3 # Suppress Go-Ahead
|
||
TMARK = 6 # Timing Mark
|
||
TTYPE = 24 # Terminal Type
|
||
NAWS = 31 # Negotiate About Window Size
|
||
LINEMO = 34 # Line Mode
|
||
|
||
READ_SIZE = 1024
|
||
|
||
|
||
class AsyncioTelnetServer:
|
||
|
||
def __init__(self, reader=None, writer=None, binary=True, echo=False):
|
||
self._reader = reader
|
||
self._writer = writer
|
||
self._clients = set()
|
||
self._lock = asyncio.Lock()
|
||
self._reader_process = None
|
||
self._current_read = None
|
||
|
||
self._binary = binary
|
||
# If echo is true when the client send data
|
||
# the data is echo on his terminal by telnet otherwise
|
||
# it's our job (or the wrapped app) to send back the data
|
||
self._echo = echo
|
||
|
||
@asyncio.coroutine
|
||
def run(self, network_reader, network_writer):
|
||
# Keep track of connected clients
|
||
self._clients.add(network_writer)
|
||
|
||
try:
|
||
# Send initial telnet session opening
|
||
if self._echo:
|
||
network_writer.write(bytes([IAC, WILL, ECHO]))
|
||
else:
|
||
network_writer.write(bytes([
|
||
IAC, WONT, ECHO,
|
||
IAC, DONT, ECHO]))
|
||
|
||
if self._binary:
|
||
network_writer.write(bytes([
|
||
IAC, WILL, SGA,
|
||
IAC, WILL, BINARY,
|
||
IAC, DO, BINARY]))
|
||
else:
|
||
network_writer.write(bytes([
|
||
IAC, WONT, SGA,
|
||
IAC, DONT, SGA,
|
||
IAC, WONT, BINARY,
|
||
IAC, DONT, BINARY]))
|
||
yield from network_writer.drain()
|
||
|
||
yield from self._process(network_reader, network_writer)
|
||
except ConnectionResetError:
|
||
with (yield from self._lock):
|
||
|
||
network_writer.close()
|
||
|
||
if self._reader_process == network_reader:
|
||
self._reader_process = None
|
||
# Cancel current read from this reader
|
||
self._current_read.cancel()
|
||
self._clients.remove(network_writer)
|
||
|
||
@asyncio.coroutine
|
||
def _get_reader(self, network_reader):
|
||
"""
|
||
Get a reader or None if another reader is already reading.
|
||
"""
|
||
with (yield from self._lock):
|
||
if self._reader_process is None:
|
||
self._reader_process = network_reader
|
||
if self._reader_process == network_reader:
|
||
self._current_read = asyncio.async(self._reader.read(READ_SIZE))
|
||
return self._current_read
|
||
return None
|
||
|
||
@asyncio.coroutine
|
||
def _process(self, network_reader, network_writer):
|
||
network_read = asyncio.async(network_reader.read(READ_SIZE))
|
||
reader_read = yield from self._get_reader(network_reader)
|
||
|
||
while True:
|
||
if reader_read is None:
|
||
reader_read = yield from self._get_reader(network_reader)
|
||
if reader_read is None:
|
||
done, pending = yield from asyncio.wait(
|
||
[
|
||
network_read,
|
||
],
|
||
timeout=1,
|
||
return_when=asyncio.FIRST_COMPLETED)
|
||
else:
|
||
done, pending = yield from asyncio.wait(
|
||
[
|
||
network_read,
|
||
reader_read
|
||
],
|
||
return_when=asyncio.FIRST_COMPLETED)
|
||
for coro in done:
|
||
data = coro.result()
|
||
# Console is closed
|
||
if len(data) == 0:
|
||
raise ConnectionResetError()
|
||
|
||
if coro == network_read:
|
||
network_read = asyncio.async(network_reader.read(READ_SIZE))
|
||
|
||
if IAC in data:
|
||
data = yield from self._IAC_parser(data, network_reader, network_writer)
|
||
if len(data) == 0:
|
||
continue
|
||
|
||
if not self._binary:
|
||
data = data.replace(b"\r\n", b"\n")
|
||
|
||
if self._writer:
|
||
self._writer.write(data)
|
||
yield from self._writer.drain()
|
||
elif coro == reader_read:
|
||
reader_read = yield from self._get_reader(network_reader)
|
||
|
||
# Replicate the output on all clients
|
||
for writer in self._clients:
|
||
writer.write(data)
|
||
yield from writer.drain()
|
||
|
||
def _IAC_parser(self, buf, network_reader, network_writer):
|
||
"""
|
||
Processes and removes any Telnet commands from the buffer.
|
||
|
||
:param buf: buffer
|
||
:returns: buffer minus Telnet commands
|
||
"""
|
||
|
||
skip_to = 0
|
||
while True:
|
||
# Locate an IAC to process
|
||
iac_loc = buf.find(IAC, skip_to)
|
||
if iac_loc < 0:
|
||
break
|
||
|
||
# Get the TELNET command
|
||
iac_cmd = bytearray([IAC])
|
||
try:
|
||
iac_cmd.append(buf[iac_loc + 1])
|
||
except IndexError:
|
||
d = yield from network_reader.read(1)
|
||
buf.extend(d)
|
||
iac_cmd.append(buf[iac_loc + 1])
|
||
|
||
# Is this just a 2-byte TELNET command?
|
||
if iac_cmd[1] not in [WILL, WONT, DO, DONT]:
|
||
if iac_cmd[1] == AYT:
|
||
log.debug("Telnet server received Are-You-There (AYT)")
|
||
network_writer.write(b'\r\nYour Are-You-There received. I am here.\r\n')
|
||
elif iac_cmd[1] == IAC:
|
||
# It's data, not an IAC
|
||
iac_cmd.pop()
|
||
# This prevents the 0xff from being
|
||
# interrupted as yet another IAC
|
||
skip_to = iac_loc + 1
|
||
log.debug("Received IAC IAC")
|
||
elif iac_cmd[1] == NOP:
|
||
pass
|
||
else:
|
||
log.debug("Unhandled telnet command: "
|
||
"{0:#x} {1:#x}".format(*iac_cmd))
|
||
|
||
# This must be a 3-byte TELNET command
|
||
else:
|
||
try:
|
||
iac_cmd.append(buf[iac_loc + 2])
|
||
except IndexError:
|
||
d = yield from network_reader.read(1)
|
||
buf.extend(d)
|
||
iac_cmd.append(buf[iac_loc + 2])
|
||
# We do ECHO, SGA, and BINARY. Period.
|
||
if iac_cmd[1] == DO:
|
||
if iac_cmd[2] not in [ECHO, SGA, BINARY]:
|
||
network_writer.write(bytes([IAC, WONT, iac_cmd[2]]))
|
||
log.debug("Telnet WON'T {:#x}".format(iac_cmd[2]))
|
||
else:
|
||
if iac_cmd[2] == SGA:
|
||
if self._binary:
|
||
network_writer.write(bytes([IAC, WILL, iac_cmd[2]]))
|
||
else:
|
||
network_writer.write(bytes([IAC, WONT, iac_cmd[2]]))
|
||
log.debug("Telnet WON'T {:#x}".format(iac_cmd[2]))
|
||
|
||
elif iac_cmd[1] == DONT:
|
||
log.debug("Unhandled DONT telnet command: "
|
||
"{0:#x} {1:#x} {2:#x}".format(*iac_cmd))
|
||
elif iac_cmd[1] == WILL:
|
||
log.debug("Unhandled WILL telnet command: "
|
||
"{0:#x} {1:#x} {2:#x}".format(*iac_cmd))
|
||
elif iac_cmd[1] == WONT:
|
||
log.debug("Unhandled WONT telnet command: "
|
||
"{0:#x} {1:#x} {2:#x}".format(*iac_cmd))
|
||
else:
|
||
log.debug("Unhandled telnet command: "
|
||
"{0:#x} {1:#x} {2:#x}".format(*iac_cmd))
|
||
|
||
# Remove the entire TELNET command from the buffer
|
||
buf = buf.replace(iac_cmd, b'', 1)
|
||
|
||
yield from network_writer.drain()
|
||
|
||
# Return the new copy of the buffer, minus telnet commands
|
||
return buf
|
||
|
||
if __name__ == '__main__':
|
||
logging.basicConfig(level=logging.DEBUG)
|
||
loop = asyncio.get_event_loop()
|
||
|
||
process = loop.run_until_complete(asyncio.async(asyncio.subprocess.create_subprocess_exec("/bin/sh", "-i",
|
||
stdout=asyncio.subprocess.PIPE,
|
||
stderr=asyncio.subprocess.STDOUT,
|
||
stdin=asyncio.subprocess.PIPE)))
|
||
server = AsyncioTelnetServer(reader=process.stdout, writer=process.stdin, binary=False, echo=False)
|
||
|
||
coro = asyncio.start_server(server.run, '127.0.0.1', 4444, loop=loop)
|
||
s = loop.run_until_complete(coro)
|
||
|
||
try:
|
||
loop.run_forever()
|
||
except KeyboardInterrupt:
|
||
pass
|
||
# Close the server
|
||
s.close()
|
||
loop.run_until_complete(s.wait_closed())
|
||
loop.close()
|