def generateInitPacket(self):
p = Packet()
p.session_id = BitArray(bin='0'*Header.SESSION_ID)
p.seq_number = BitArray(uint=self.seqnumber,length=Header.SEQ_NUMBER)
p.ack = BitArray(bin='0'*Header.ACK)
p.data_len = BitArray(uint=len(self.tag),length=Header.DATA_LEN)
p.flags = BitArray(uint=Flags.SYNC,length=Header.FLAGS)
p.optional_headers = True
p.sync_type = BitArray(uint=Sync.REQUEST_AUTH,length=OptionalHeader.SYNC_TYPE)
p.content = BitArray(bytes=BitArray(hex=self.tag).bytes, length=Sizes.TAG)
return p
def generateAuthResponsePacket(self, req, sessionID):
p = Packet()
p.session_id = sessionID
p.seq_number = BitArray(uint=1, length=Header.SEQ_NUMBER)
p.ack = req.seq_number
p.data_len = BitArray(bin='0' * Header.DATA_LEN)
p.flags = BitArray(uint=Flags.SYNC, length=Header.FLAGS)
p.optional_headers = True
p.sync_type = BitArray(uint=Sync.RESPONSE_AUTH,
length=OptionalHeader.SYNC_TYPE)
p.content = BitArray()
return p
def generateTerminatePacket(self,packt):
p = Packet()
p.session_id = self.sid
self.seqnumber+=1
p.seq_number = BitArray(uint=self.seqnumber,length=Header.SEQ_NUMBER)
p.ack = packt.seq_number
p.data_len = BitArray(bin='0'*Header.DATA_LEN)
p.flags = BitArray(uint=Flags.SYNC,length=Header.FLAGS)
p.optional_headers = True
p.sync_type = BitArray(uint=Sync.SESSION_TERMINATION,length=OptionalHeader.SYNC_TYPE)
p.content = BitArray()
return p
def generateReintializationPacket(self,packt):
p = Packet()
p.session_id = self.sid
self.seqnumber+=1
p.seq_number = BitArray(uint=self.seqnumber,length=Header.SEQ_NUMBER)
p.ack = packt.seq_number
p.data_len = BitArray(bin='0'*Header.DATA_LEN)
p.flags = BitArray(uint=Flags.SYNC,length=Header.FLAGS)
p.optional_headers = True
p.sync_type = BitArray(uint=Sync.REINITIALIZING,length=OptionalHeader.SYNC_TYPE)
p.content = BitArray()
return p
def buildPacket(header, body):
p = Packet()
p.session_id = header[0:Offsets.SESSION_ID]
p.seq_number = header[Offsets.SESSION_ID:Offsets.SEQ_NUMBER]
p.ack = header[Offsets.SEQ_NUMBER:Offsets.ACK]
p.data_len = header[Offsets.ACK:Offsets.DATA_LEN]
p.flags = header[Offsets.DATA_LEN:Offsets.FLAGS]
p.sync_type = None
p.content = None
if p.isFlagActive(Flags.SYNC):
p.sync_type = BitArray(bin=body.bin[0:Offsets.SYNC_TYPE])
p.content = BitArray(bin=body.bin[Offsets.SYNC_TYPE:])
p.optional_headers = True
else:
p.sync_type = BitArray()
p.content = BitArray(bin=body.bin)
return p