def test_reject_negative_negotiation():
opt = StreamParser.OptionNegotiation(
OPTIONS.TM, OPTIONS.TM.value, StreamParser.Host.LOCAL, False
)
assert opt.refuse() == StreamParser.OptionNegotiation(
OPTIONS.TM, OPTIONS.TM.value, StreamParser.Host.LOCAL, True
)
def test_accept_negative_negotiation():
opt = StreamParser.OptionNegotiation(
OPTIONS.TM, OPTIONS.TM.value, StreamParser.Host.LOCAL, False
)
assert opt.accept() == StreamParser.OptionNegotiation(
OPTIONS.TM, OPTIONS.TM.value, StreamParser.Host.LOCAL, False
)
def test_stream_user_data_crlf(stream_parser):
events = stream_parser.stream_updates([Tokenizer.StreamData(b"Hello,\r\nworld!")])
assert events == [
StreamParser.UserData("Hello,"),
StreamParser.UserData("\n"),
StreamParser.UserData("world!"),
]
def __init__(self, reader, writer):
self.reader = reader
self.writer = writer
self.encoder = StreamStuffer()
self.tokenizer = Tokenizer()
self.parser = StreamParser()
self.line_buffer = LineBuffer()
self.update_buffer = []
self.prompt_mgr = None
self.echo_state = EchoOptionState()
def test_stream_command_in_crlf(stream_parser):
events = stream_parser.stream_updates(
[
Tokenizer.StreamData(b"abc\r"),
Tokenizer.Command(B.NOP, B.NOP.value),
Tokenizer.StreamData(b"\ndef"),
]
)
assert events == [
StreamParser.UserData("abc"),
StreamParser.Command(B.NOP, B.NOP.value),
StreamParser.UserData("\n"),
StreamParser.UserData("def"),
]
def test_stuffer_option_recognized(stuffer):
stuffed = stuffer.stuff(
StreamParser.OptionNegotiation(
OPTIONS.TM, OPTIONS.TM.value, StreamParser.Host.PEER, False
)
)
assert stuffed == (B.IAC.byte + B.DONT.byte + OPTIONS.TM.byte)
def _write(self, text):
if isinstance(text, str):
text = StreamParser.UserData(text)
out_data = self.encoder.stuff(text)
logger.debug("writing", extra={"data": out_data})
self.writer.write(out_data)
def test_stream_sb(stream_parser):
events = stream_parser.stream_updates(
[
Tokenizer.Option(B.SB, None, 42),
Tokenizer.StreamData(b"1234"),
Tokenizer.Command(B.SE, B.SE.value),
]
)
assert events == [StreamParser.OptionSubnegotiation(None, 42)]
def test_stream_dont(stream_parser):
events = stream_parser.stream_updates(
[Tokenizer.Option(B.DONT, OPTIONS.TM, OPTIONS.TM.value)]
)
assert events == [
StreamParser.OptionNegotiation(
OPTIONS.TM, OPTIONS.TM.value, StreamParser.Host.LOCAL, False
)
]
def test_stuffer_text(stuffer):
stuffed = stuffer.stuff(StreamParser.UserData("abc"))
assert stuffed == b"abc"
def test_stream_user_data(stream_parser):
events = stream_parser.stream_updates([Tokenizer.StreamData(b"Hello, world!")])
assert events == [StreamParser.UserData("Hello, world!")]
def stream_parser():
return StreamParser()
def test_integration(tokenizer, stream_parser):
data = (
b"Hel"
+ B.IAC.byte
+ B.NOP.byte
+ b"lo,\r"
+
# start a subneg
B.IAC.byte
+ B.SB.byte
+ bytes([42])
+ b"abc"
+
# literal IAC SE as subneg data
B.IAC.byte
+ B.IAC.byte
+ B.SE.byte
+ b"def"
+
# finish the subneg
B.IAC.byte
+ B.SE.byte
+ b"\0wor"
+ B.IAC.byte
+ B.DO.byte
+ bytes([42])
+ b"ld!"
)
atomized = [bytes([b]) for b in data] # process it one byte at a time
toks = sum([tokenizer.tokens(b) for b in atomized], [])
events = sum([stream_parser.stream_updates([tok]) for tok in toks], [])
assert events == [
StreamParser.UserData("H"),
StreamParser.UserData("e"),
StreamParser.UserData("l"),
StreamParser.Command(B.NOP, B.NOP.value),
StreamParser.UserData("l"),
StreamParser.UserData("o"),
StreamParser.UserData(","),
StreamParser.OptionSubnegotiation(None, 42),
StreamParser.UserData("\r"),
StreamParser.UserData("w"),
StreamParser.UserData("o"),
StreamParser.UserData("r"),
StreamParser.OptionNegotiation(None, 42, StreamParser.Host.LOCAL, True),
StreamParser.UserData("l"),
StreamParser.UserData("d"),
StreamParser.UserData("!"),
]
def test_stuffer_option_unrecognized(stuffer):
stuffed = stuffer.stuff(
StreamParser.OptionNegotiation(None, 42, StreamParser.Host.PEER, False)
)
assert stuffed == (B.IAC.byte + B.DONT.byte + bytes([42]))
def test_stuffer_crlf(stuffer):
stuffed = stuffer.stuff(StreamParser.UserData("abc\ndef\rghi"))
assert stuffed == b"abc\r\ndef\r\0ghi"
def test_stuffer_nonascii(stuffer):
try:
stuffed = stuffer.stuff(StreamParser.UserData("abcdéf"))
assert False # should have thrown an exception
except UnicodeEncodeError:
pass # expected behavior under test
def make_negotiation(self, state):
return StreamParser.OptionNegotiation(OPTIONS.ECHO, OPTIONS.ECHO.value,
StreamParser.Host.LOCAL, state)
def test_stream_user_data_nonascii(stream_parser):
events = stream_parser.stream_updates([Tokenizer.StreamData(b"abc\xabdef")])
assert events == [StreamParser.UserData("abcdef")]
def test_stream_wont(stream_parser):
events = stream_parser.stream_updates([Tokenizer.Option(B.WONT, None, 42)])
assert events == [
StreamParser.OptionNegotiation(None, 42, StreamParser.Host.PEER, False)
]
def test_stream_will(stream_parser):
events = stream_parser.stream_updates([Tokenizer.Option(B.WILL, None, 42)])
assert events == [
StreamParser.OptionNegotiation(None, 42, StreamParser.Host.PEER, True)
]
def test_stream_command(stream_parser):
events = stream_parser.stream_updates([Tokenizer.Command(B.NOP, B.NOP.value)])
assert events == [StreamParser.Command(B.NOP, B.NOP.value)]
class Terminal:
READ_SIZE = 2**12 # arbitrary pleasant number?
def __init__(self, reader, writer):
self.reader = reader
self.writer = writer
self.encoder = StreamStuffer()
self.tokenizer = Tokenizer()
self.parser = StreamParser()
self.line_buffer = LineBuffer()
self.update_buffer = []
self.prompt_mgr = None
self.echo_state = EchoOptionState()
async def __aenter__(self):
return self
async def __aexit__(self, exc_type, exc_value, traceback):
await self.close()
async def close(self):
await self.writer.drain()
self.writer.close()
await self.writer.wait_closed()
async def sleep(self, secs):
await self.writer.drain()
await asyncio.sleep(secs)
async def write(self, texts, drain=False):
if texts is None:
texts = []
if not isinstance(texts, list):
texts = [texts]
for text in texts:
self._write(text)
if drain:
await self.writer.drain()
def _write(self, text):
if isinstance(text, str):
text = StreamParser.UserData(text)
out_data = self.encoder.stuff(text)
logger.debug("writing", extra={"data": out_data})
self.writer.write(out_data)
@contextlib.contextmanager
def prompt(self, prompt):
self.prompt_mgr = Prompt(prompt)
try:
yield
finally:
self.prompt_mgr = None
async def input(self, prompt):
with self.prompt(prompt):
return await self._input_line()
async def input_secret(self, prompt):
with self.prompt(prompt):
async with self.echo_off():
result = await self._input_line()
# echo peer's LF
await self.write("\n")
return result
async def _input_line(self):
while True:
line = await self._handle_input_once()
if line:
return line
async def _handle_input_once(self):
await self.require_line_buffer()
annotations, line = self.line_buffer.pop()
for annotation in annotations:
handler_name = "annotation_" + annotation.__class__.__name__
handler = getattr(self, handler_name)
await handler(annotation)
return line
async def require_line_buffer(self):
while not self.line_buffer.has_line():
await self.require_update_buffer()
update = self.update_buffer.pop(0)
await self.write(self.handle_update(update), drain=True)
async def require_update_buffer(self):
while not self.update_buffer:
await self.write(self.prompt_mgr.require_has_prompt(), drain=True)
self.update_buffer = await self.fetch_updates()
async def fetch_updates(self):
data = await self.reader.read(self.READ_SIZE)
logger.debug("read", extra={"data": data})
if not data:
raise EOFError()
toks = self.tokenizer.tokens(data)
return self.parser.stream_updates(toks)
async def annotation_TimingMark(self, annotation):
await self.write(annotation.option.accept(), drain=True)
#
# locally requested state changes
#
@contextlib.asynccontextmanager
async def echo_off(self):
# The way we turn echo off is by turning on the server echo option
# and then just not echoing anythiing.
await self.write(self.echo_state.local_request(True), drain=True)
try:
yield
finally:
await self.write(self.echo_state.local_request(False), drain=True)
#
# input stream updates
#
def handle_update(self, update):
handle = getattr(self, "update_" + update.__class__.__name__, None)
if not handle:
logger.info("unhandled update", extra={"update": update})
return
return handle(update)
def update_UserData(self, update):
self.line_buffer.append(update.data)
self.prompt_mgr.mark_user_data()
#
# telnet options
#
def update_OptionNegotiation(self, request):
handler = self.get_option_handler(request)
return handler(request)
def get_option_handler(self, request):
if request.option is None:
return self.option_unhandled
handler_name = "option_" + request.option.name
handler = getattr(self, "option_" + request.option.name, None)
return handler or self.option_unhandled
def option_TM(self, request):
if not request.state:
# client is rejecting this option. we only send it when it's
# requested, so it's safe to ignore this.
logger.debug("ignoring unmatched request",
extra={"request": request})
return
if request.host == StreamParser.Host.LOCAL:
# client is requesting a TM.
logger.info(f"ACCEPTING", extra={"request": request})
self.line_buffer.annotate(self.TimingMark(request))
return
# otherwise client is sending us a TM, which we didn't request. ignore it.
logger.debug("ignoring unrequested request",
extra={"request": request})
def option_ECHO(self, request):
return self.echo_state.handle_negotiation(request)
def option_unhandled(self, request):
if request.state:
# Peer is requesting an unsupported option. Refuse.
logger.info("rejecting option", extra={"request": request})
return request.refuse()
# else client is requesting to disable an option. we support no
# options, so all are off. ignore it.
else:
logger.debug("ignoring option", extra={"request": request})
# telnet commands
def update_Command(self, command):
handler = self.get_command_handler(command)
return handler(command)
def get_command_handler(self, command):
if command.command is None:
return self.command_unhandled
handler_name = "command_" + command.command.name
handler = getattr(self, handler_name, None)
return handler or self.command_unhandled
def command_unhandled(self, command):
logger.info("unhandled command", extra={"command": command})
def command_IP(self, command):
logger.debug("interrupt process")
# Currently we only ever read peer input during prompting, so
# there's no process to interrupt. For bonus complexity there's a
# fair chance the peer will send a timing mark request and discard
# everything it gets before we acknowledge, so there's no point
# sending a prompt unless we're sure they're ready. For no just
# clear the input.
self.line_buffer.clear()
self.prompt_mgr.mark_interrupt()
TimingMark = collections.namedtuple("TimingMark", ["option"])