示例#1
0
def sendAckOrFin(ackNumber,seqNum,ackFlag,finFlag):
	# Call the function in rawIp.py to get the IP header based on the arguments of this function	
	ipHeader = make_ip_header(sourceIp=sourceIp,destinationIp = destinationIp)
	#there is no user data in the ACK packets since the client is not gonna send any more data to the server
	user_data = ''
	# tcp header fields
	# Call the function in rawTcp.py to get the TCP header based on the arguments of this function
	tcpHeader = make_tcp_packet(sourceIp ,destinationIp,tcp_source_global,tcp_destination_global,
					seqNum,ackNumber,finFlag,0,0,ackFlag,user_data)

	#Making the final packet
	packet = ipHeader + tcpHeader + user_data

	#Send the ACK or FIN Packet
	sendSocket.sendto(packet,(destinationIp,0))
示例#2
0
def tcp_handshake_syn():
	# Call the function in rawIp.py to get the IP header based on the arguments of this function	
	ip_header = make_ip_header(sourceIp=sourceIp,destinationIp = destinationIp)
	#there is no user data in the first SYN packet since the client is initiating the three way handshake
	user_data = ''
	# Call the function in rawTcp.py to get the TCP header based on the arguments of this function
	tcp_header = make_tcp_packet(sourceIp,destinationIp,tcp_source_global,
			tcp_destination_global,tcp_seq_global,0,0,1,0,0,user_data)

	#creating the final packet
	packet = ip_header + tcp_header + user_data
	 
	#Send the packet finally - the port specified has no effect
	sendSocket.sendto(packet, (destinationIp , 0 ))

	# receive a packet
	packetReceived = True;
	while packetReceived:
	    packet = receiveSocket.recvfrom(tcp_source_global)
	    packet = packet[0]
	    ip_header = packet[0:20]
	    ipHeader = unpack('!BBHHHBBH4s4s' , ip_header)
	    version_ihl = ipHeader[0]
            version = version_ihl >> 4
	    ihl = version_ihl & 0xF
	    iph_length = ihl * 4

     	    tcp_header = packet[iph_length:iph_length+20]
 	    tcpHeader = unpack('!HHLLBBHHH' , tcp_header)
		
            source_port = tcpHeader[0]
	    dest_port = tcpHeader[1]
	    sequence = tcpHeader[2]
	    acknowledgement = tcpHeader[3]
	    dataOffset_reserved = tcpHeader[4]
	    tcpHeader_length = dataOffset_reserved >> 4

	    if  (acknowledgement == tcp_seq_global + 1) and (dest_port == tcp_source_global) :
		headerSize = iph_length + tcpHeader_length * 4
		data_size = len(packet) - headerSize
		#get data from the packet
		data = packet[headerSize:]
		packetReceived = False;
		#calling the function to perform handshakee by sending ACK for the SYN ACK packet received
		#the sequence will be increased by 1 and the ackNumber will be same as the seq number of the
		#received packet
		send_req(ackNum = sequence + 1,seqNum = acknowledgement)
示例#3
0
def send_req(ackNum,seqNum):
	# Call the function in rawIp.py to get the IP header based on the arguments of this function	
	ip_header = make_ip_header(sourceIp=sourceIp,destinationIp = destinationIp)


	# tcp data field
	user_data ='GET '+ filePath +' HTTP/1.0\r\nHost: '+ address +'\r\nUser-Agent: HTTPTool/1.1\r\nAccept-Language: en-US,en;q=0.5\r\nConnection: keep-alive\r\n\r\n';
	# Call the function in rawTcp.py to get the TCP header based on the arguments of this function	
	tcp_header = make_tcp_packet(sourceIp ,destinationIp,tcp_source_global,tcp_destination_global,
					seqNum ,ackNum,0,0,1,1,user_data)

	# this is the final packet that needs to be sent to the destination
	packet = ip_header + tcp_header + user_data

	sendSocket.sendto(packet, (destinationIp , 0 )) 
	# receive the ACK packet from the server .. this packet contains the sequence number for the receiver used for
	# the rest of the communication
	#sending the seq number of the last acked packet
	get_file(nextSeq = ackNum,clientSeqNum = seqNum + len(user_data))