def test1_createProtocolMessages( self ):
# An empty message consists only of a header.
self.failUnless(len(message.createProtocolMessages("")[0]) == \
const.HDR_LENGTH)
msg = message.createProtocolMessages('X' * const.MPU)
self.failUnless((len(msg) == 1) and (len(msg[0]) == const.MTU))
msg = message.createProtocolMessages('X' * (const.MPU + 1))
self.failUnless((len(msg) == 2) and \
(len(msg[0]) == const.MTU) and \
(len(msg[1]) == (const.HDR_LENGTH + 1)))
def sendRemote(self, data, flags=const.FLAG_PAYLOAD):
"""
Send data to the remote end after a connection was established.
The given `data' is first encapsulated in protocol messages. Then, the
protocol message(s) are sent over the wire. The argument `flags'
specifies the protocol message flags with the default flags signalling
payload.
"""
log.debug("Processing %d bytes of outgoing data." % len(data))
# Wrap the application's data in ScrambleSuit protocol messages.
messages = message.createProtocolMessages(data, flags=flags)
blurb = "".join([
msg.encryptAndHMAC(self.sendCrypter, self.sendHMAC)
for msg in messages
])
# Flush data chunk for chunk to obfuscate inter-arrival times.
if const.USE_IAT_OBFUSCATION:
if len(self.choppingBuf) == 0:
self.choppingBuf.write(blurb)
reactor.callLater(self.iatMorpher.randomSample(),
self.flushPieces)
else:
# flushPieces() is still busy processing the chopping buffer.
self.choppingBuf.write(blurb)
else:
padBlurb = self.pktMorpher.getPadding(self.sendCrypter,
self.sendHMAC, len(blurb))
self.circuit.downstream.write(blurb + padBlurb)
def sendRemote( self, data, flags=const.FLAG_PAYLOAD ):
"""
Send data to the remote end after a connection was established.
The given `data' is first encapsulated in protocol messages. Then, the
protocol message(s) are sent over the wire. The argument `flags'
specifies the protocol message flags with the default flags signalling
payload.
"""
log.debug("Processing %d bytes of outgoing data." % len(data))
# Wrap the application's data in ScrambleSuit protocol messages.
messages = message.createProtocolMessages(data, flags=flags)
blurb = "".join([msg.encryptAndHMAC(self.sendCrypter,
self.sendHMAC) for msg in messages])
# Flush data chunk for chunk to obfuscate inter-arrival times.
if const.USE_IAT_OBFUSCATION:
if len(self.choppingBuf) == 0:
self.choppingBuf.write(blurb)
reactor.callLater(self.iatMorpher.randomSample(),
self.flushPieces)
else:
# flushPieces() is still busy processing the chopping buffer.
self.choppingBuf.write(blurb)
else:
padBlurb = self.pktMorpher.getPadding(self.sendCrypter,
self.sendHMAC,
len(blurb))
self.circuit.downstream.write(blurb + padBlurb)
def sendRemote( self, data, flags=const.FLAG_PAYLOAD ):
"""
Send data to the remote end after a connection was established.
The given `data' is first encapsulated in protocol messages. Then, the
protocol message(s) are sent over the wire. The argument `flags'
specifies the protocol message flags with the default flags signalling
payload.
"""
log.debug("Processing %d bytes of outgoing data." % len(data))
# Wrap the application's data in ScrambleSuit protocol messages.
messages = message.createProtocolMessages(data, flags=flags)
# Let the packet morpher tell us how much we should pad.
paddingLen = self.pktMorpher.calcPadding(sum([len(msg) for
msg in messages]))
# If padding > header length, a single message will do...
if paddingLen > const.HDR_LENGTH:
messages.append(message.new("", paddingLen=paddingLen -
const.HDR_LENGTH))
# ...otherwise, we use two padding-only messages.
else:
messages.append(message.new("", paddingLen=const.MPU -
const.HDR_LENGTH))
messages.append(message.new("", paddingLen=paddingLen))
blurb = "".join([msg.encryptAndHMAC(self.sendCrypter,
self.sendHMAC) for msg in messages])
# Flush data chunk for chunk to obfuscate inter arrival times.
if const.USE_IAT_OBFUSCATION:
if len(self.choppingBuf) == 0:
self.choppingBuf.write(blurb)
reactor.callLater(self.iatMorpher.randomSample(),
self.flushPieces)
else:
# flushPieces() is still busy processing the chopping buffer.
self.choppingBuf.write(blurb)
else:
self.circuit.downstream.write(blurb)
