def receive(self, packet):
"""Receives a packet. Based on its message, returns
a response packet."""
# Reads basic data from received packet
clientIp = packet.getOriginIp()
segment = packet.getSegment()
clientPort = segment.getOriginPort()
msg = packet.getSegment().getMessage()
# Adjusts ack and seq numbers
ackNumber = segment.getSeqNumber() + segment.getMessageSize()
seqNumber = segment.getAckNumber()
# Received a SYN packet; establish connection with client
if segment.getSYN() is True:
clientIp = packet.getOriginIp()
synSegment = TcpSegment("", self.serverPort, clientPort)
synSegment.setSYN()
synSegment.setACK()
synSegment.setAckNumber(1)
synSegment.setSeqNumber(seqNumber)
return IpDatagram(synSegment, self.serverIp, clientIp)
# Received a FIN packet; close connection with client
elif segment.getFIN() is True:
clientIp = packet.getOriginIp()
finSegment = TcpSegment("", self.serverPort, clientPort)
finSegment.setFIN()
finSegment.setACK()
finSegment.setAckNumber(ackNumber + 1)
finSegment.setSeqNumber(seqNumber)
return IpDatagram(finSegment, self.serverIp, clientIp)
# Received an ACK packet; do nothing
elif msg == "":
return None
# Packet contains a message from the client;
# send an ACK packet and a message packet
# ACK packet
ackSegment = TcpSegment("", self.serverPort, clientPort)
ackSegment.setACK()
ackSegment.setAckNumber(ackNumber)
ackSegment.setSeqNumber(seqNumber)
ackPacket = IpDatagram(ackSegment, self.serverIp, clientIp)
# Response packet (contains a non-empty message)
respMessage = self.__parseMessage([clientIp, clientPort], msg)
respSegment = TcpSegment(respMessage, self.serverPort, clientPort)
respSegment.setACK()
respSegment.setAckNumber(ackNumber)
respSegment.setSeqNumber(seqNumber)
respPacket = IpDatagram(respSegment, self.serverIp, clientIp)
return [ackPacket, respPacket]
def receive(self, packet):
"""Receives and parses a packet from the IRC server."""
segment = packet.getSegment()
msg = segment.getMessage()
# Packet contains a message from the server;
# first, read message contained in the packet
# Received CONNECT confirmation
if msg[0] == '0':
self.serverIp = packet.getOriginIp()
# Received USER confirmation
elif msg[0] == '1':
pass
# Received QUIT confirmation
elif msg[0] == '2':
self.mustClose = True
# Then, create and send an ACK packet
ackSegment = TcpSegment("", self.clientPort, self.serverPort)
# Adjusts ack and seq numbers
self.ackNumber = segment.getSeqNumber() + segment.getMessageSize()
self.seqNumber = segment.getAckNumber()
ackSegment.setACK()
ackSegment.setAckNumber(self.ackNumber)
ackSegment.setSeqNumber(self.seqNumber)
ackPacket = IpDatagram(ackSegment, self.clientIp, self.serverIp)
if self.mustClose:
self.mustClose = False
finSegment = TcpSegment("", self.clientPort, self.serverPort)
finSegment.setFIN()
finSegment.setAckNumber(self.ackNumber)
finSegment.setSeqNumber(self.seqNumber)
finPacket = IpDatagram(finSegment, self.clientIp, self.serverIp)
self.clientPort = None
self.serverIp = None
return [ackPacket, finPacket]
return ackPacket
def receive(self, packet):
"""Receives and parses a packet from the IRC server."""
segment = packet.getSegment()
msg = segment.getMessage()
# Packet contains a message from the server;
# first, read message contained in the packet
# Received CONNECT confirmation
if msg[0] == '0':
self.serverIp = packet.getOriginIp()
# Received USER confirmation
elif msg[0] == '1':
pass
# Received QUIT confirmation
elif msg[0] == '2':
self.mustClose = True
# Then, create and send an ACK packet
ackSegment = TcpSegment("", self.clientPort, self.serverPort)
# Adjusts ack and seq numbers
self.ackNumber = segment.getSeqNumber() + segment.getMessageSize()
self.seqNumber = segment.getAckNumber()
ackSegment.setACK()
ackSegment.setAckNumber(self.ackNumber)
ackSegment.setSeqNumber(self.seqNumber)
ackPacket = IpDatagram(ackSegment, self.clientIp, self.serverIp)
if self.mustClose:
self.mustClose = False
finSegment = TcpSegment("", self.clientPort, self.serverPort)
finSegment.setFIN()
finSegment.setAckNumber(self.ackNumber)
finSegment.setSeqNumber(self.seqNumber)
finPacket = IpDatagram(finSegment, self.clientIp, self.serverIp)
self.clientPort = None
self.serverIp = None
return [ackPacket, finPacket]
return ackPacket
