def getTCPHeader(self, localhostIP, destinationIP, user_request):
tcpheader_obj = TCPHeader()
tcpheader_obj.setValues(self.sourcePortNum, self.destinationPortNum, self.seq_num, self.current_ack_no, 0, 1, 0, user_request)
tcp_header = tcpheader_obj.build(localhostIP, destinationIP)
return tcp_header
def getTCPHeader(self, localhostIP, destinationIP, user_request):
tcpheader_obj = TCPHeader()
tcpheader_obj.setValues(
self.sourcePortNum, self.destinationPortNum, self.seq_num, self.current_ack_no, 0, 1, 0, user_request
)
tcp_header = tcpheader_obj.build(localhostIP, destinationIP)
return tcp_header
def startTearDown(self, local_current_ack_no, localhostIP, destinationIP, sendSock, receiveSock):
# Sends ACK to server of the received packet content
self.sendAckToServer(local_current_ack_no, localhostIP, destinationIP, sendSock)
self.ip_packet_ID = self.ip_packet_ID + 1
ipheader = self.getIPHeader(localhostIP, destinationIP, self.ip_packet_ID)
tcpobj = TCPHeader()
tcpobj.setValues(self.sourcePortNum, self.destinationPortNum, self.seq_num, local_current_ack_no, 0, 1, 1, "")
tcpheader = tcpobj.build(localhostIP, destinationIP)
packet = ipheader + tcpheader + ""
sendSock.sendto(packet, (destinationIP, 80))
start_time = time.clock()
while True:
try:
receivedPacket = receiveSock.recvfrom(65565)
except:
print "Exception in tear down"
sys.exit(2)
packetData = receivedPacket[0]
received_IPHeader = packetData[0:20]
ipheader = IPHeader(0, 0, 0)
ipheader.extract(received_IPHeader)
checksum = self.calculateCheckSum(received_IPHeader)
spent_Time = time.clock() - start_time
# Resend if time exceeds 1min
if spent_Time > 60:
sendSock.sendto(packet, (destinationIP, 80))
start_time = time.clock()
# Checks if the protocol is 6, and checks the source and destination in the IP Packet
if (
ipheader.protocol == 6
and ipheader.sourceIP == destinationIP
and ipheader.destinationIP == localhostIP
and checksum == 0
):
get_TCPHeader = self.getTCPHeaderFromIPHeader(packetData, ipheader)
tcpheader = TCPHeader()
tcpheader.extract(get_TCPHeader)
if (
tcpheader.sourcePort == self.destinationPortNum
and tcpheader.destPort == self.sourcePortNum
and tcpheader.ackNo == self.seq_num + 1
):
return
def sendAckToServer(self, local_current_ack_no, localhostIP, destinationIP, sendSock):
self.ip_packet_ID = self.ip_packet_ID + 1
ipheader = self.getIPHeader(localhostIP, destinationIP, self.ip_packet_ID)
tcpobj = TCPHeader()
tcpobj.setValues(self.sourcePortNum, self.destinationPortNum, self.seq_num, local_current_ack_no, 0, 1, 0, "")
tcpheader = tcpobj.build(localhostIP, destinationIP)
packet = ipheader + tcpheader + ""
sendSock.sendto(packet, (destinationIP, self.destinationPortNum))
def sendAckToServer(self, local_current_ack_no, localhostIP, destinationIP, sendSock):
self.ip_packet_ID = self.ip_packet_ID + 1
ipheader = self.getIPHeader(localhostIP, destinationIP, self.ip_packet_ID)
tcpobj = TCPHeader()
tcpobj.setValues(self.sourcePortNum, self.destinationPortNum, self.seq_num, local_current_ack_no, 0, 1, 0, "")
tcpheader = tcpobj.build(localhostIP, destinationIP)
packet = ipheader + tcpheader + ""
sendSock.sendto(packet, (destinationIP, self.destinationPortNum))
def buildSYNPacket(self, localhostIP, destinationIP):
IPHeaderObj = IPHeader(localhostIP, destinationIP, self.ip_packet_ID)
ipHeader = IPHeaderObj.build()
userData = ""
TCPObj = TCPHeader()
#Set the SYN Flag
TCPObj.setValues(self.sourcePortNum, self.destinationPortNum, self.seq_num, self.current_ack_no, 1, 0, 0, userData)
tcpHeader = TCPObj.build(localhostIP, destinationIP)
SYNPacket = ipHeader + tcpHeader + userData
return SYNPacket
def buildSYNPacket(self, localhostIP, destinationIP):
IPHeaderObj = IPHeader(localhostIP, destinationIP, self.ip_packet_ID)
ipHeader = IPHeaderObj.build()
userData = ""
TCPObj = TCPHeader()
# Set the SYN Flag
TCPObj.setValues(
self.sourcePortNum, self.destinationPortNum, self.seq_num, self.current_ack_no, 1, 0, 0, userData
)
tcpHeader = TCPObj.build(localhostIP, destinationIP)
SYNPacket = ipHeader + tcpHeader + userData
return SYNPacket
def startTearDown(self, local_current_ack_no, localhostIP, destinationIP, sendSock, receiveSock):
# Sends ACK to server of the received packet content
self.sendAckToServer(local_current_ack_no, localhostIP, destinationIP, sendSock)
self.ip_packet_ID = self.ip_packet_ID + 1
ipheader = self.getIPHeader(localhostIP, destinationIP, self.ip_packet_ID)
tcpobj = TCPHeader()
tcpobj.setValues(self.sourcePortNum, self.destinationPortNum, self.seq_num, local_current_ack_no, 0, 1, 1, "")
tcpheader = tcpobj.build(localhostIP, destinationIP)
packet = ipheader + tcpheader + ""
sendSock.sendto(packet, (destinationIP, 80))
start_time = time.clock()
while True:
try:
receivedPacket = receiveSock.recvfrom(65565)
except:
print "Exception in tear down"
sys.exit(2)
packetData = receivedPacket[0]
received_IPHeader = packetData[0:20]
ipheader = IPHeader(0, 0, 0)
ipheader.extract(received_IPHeader)
checksum = self.calculateCheckSum(received_IPHeader)
spent_Time = time.clock() - start_time
# Resend if time exceeds 1min
if spent_Time > 60:
sendSock.sendto(packet, (destinationIP, 80))
start_time = time.clock()
# Checks if the protocol is 6, and checks the source and destination in the IP Packet
if ipheader.protocol == 6 and ipheader.sourceIP == destinationIP and ipheader.destinationIP == localhostIP and checksum == 0:
get_TCPHeader = self.getTCPHeaderFromIPHeader(packetData, ipheader)
tcpheader = TCPHeader()
tcpheader.extract(get_TCPHeader)
if tcpheader.sourcePort == self.destinationPortNum and tcpheader.destPort == self.sourcePortNum and tcpheader.ackNo == self.seq_num + 1:
return
