def test_repr():
"""Test writer.__repr__ for client and server viewpoint."""
srv = telnetlib3.TelnetWriter(transport=None, protocol=None, server=True)
clt = telnetlib3.TelnetWriter(transport=None, protocol=None, client=True)
assert repr(srv) == ('<TelnetWriter server '
'mode:local +lineflow -xon_any +slc_sim>')
assert repr(clt) == ('<TelnetWriter client '
'mode:local +lineflow -xon_any +slc_sim>')
def test_writer_instantiation_safety():
"""On instantiation, one of server or client must be specified."""
telnetlib3.TelnetWriter(transport=None, protocol=None, client=True)
with pytest.raises(TypeError):
# must define at least server=True or client=True
telnetlib3.TelnetWriter(transport=None, protocol=None)
with pytest.raises(TypeError):
# but cannot define both!
telnetlib3.TelnetWriter(transport=None, protocol=None,
server=True, client=True)
def test_bad_iac():
"""Test using writer.iac for something outside of DO/DONT/WILL/WONT."""
from telnetlib3.telopt import NOP
writer = telnetlib3.TelnetWriter(transport=None,
protocol=None,
server=True)
with pytest.raises(ValueError):
writer.iac(NOP)
def test_illegal_2byte_iac():
"""Given an illegal 2byte IAC command, raise ValueError."""
writer = telnetlib3.TelnetWriter(transport=None,
protocol=None,
server=True)
from telnetlib3.telopt import IAC, SGA
writer.feed_byte(IAC)
with pytest.raises(ValueError):
# IAC SGA(b'\x03'): not a legal 2-byte cmd
writer.feed_byte(SGA)
def test_sb_interrupted():
"""IAC SB gets interrupted by IAC command, reseting and exiting state."""
# when within an SB buffer, all SB protocols we know about remark that
# IAC must be escaped -- for example, the NAWS negotiation of a 65535
# by 0 window size should be '\xff\xff\xff\xff\x00\x00' -- so if we
# receive an IAC **not** followed by an IAC while within a sub-negotiation
# buffer, we are in miscommunication. The remote end is not RFC complaint,
# not a telnet server, or is simply fuzzing us.
#
# instead of awaiting the unlikely SE, and throwing all intermediary bytes
# out, we just clear what we have received so far within this so called
# 'SB', and exit the sb buffering state.
from telnetlib3.telopt import IAC, SB, TM, SE
import logging
log = logging.getLogger(__name__)
log.setLevel(logging.DEBUG)
writer = telnetlib3.TelnetWriter(transport=None,
protocol=None,
server=True,
log=log)
given = IAC + SB + b"sbdata-\xff\xff-sbdata"
sb_expected = b"sbdata-\xff-sbdata"
for val in given:
writer.feed_byte(bytes([val]))
assert b"".join(writer._sb_buffer) == sb_expected
writer.feed_byte(IAC)
with pytest.raises(ValueError, match="SB unhandled"):
# [SB + b's'] unsolicited,
writer.feed_byte(SE)
# the 'IAC TM' interrupts and ends the SB buffer
given = IAC + SB + b"sbdata-" + IAC + TM + b"-sbdata"
for val in given:
writer.feed_byte(bytes([val]))
assert b"".join(writer._sb_buffer) == b""
# so, even if you sent an IAC + SE, that is no longer
# legal for this state.
writer.feed_byte(b"x")
writer.feed_byte(IAC)
with pytest.raises(ValueError, match="not a legal 2-byte cmd"):
writer.feed_byte(SE)
def test_legal_2byte_iac():
"""Nothing special about a 2-byte IAC, test wiring a callback."""
from telnetlib3.telopt import IAC, NOP
import threading
called = threading.Event()
def callback(cmd):
assert cmd == NOP
called.set()
writer = telnetlib3.TelnetWriter(transport=None,
protocol=None,
server=True)
writer.set_iac_callback(cmd=NOP, func=callback)
writer.feed_byte(IAC)
writer.feed_byte(NOP)
assert called.is_set()
