def sendSYN(rxp_socket):
print "Sending SYN! from socket", rxp_socket
header = RxPPacketHeader()
header.src_port = rxp_socket.source_address[1]
header.dst_port = rxp_socket.destination_address[1]
header.syn_flag = 1
packet = RxPPacket(header)
number_of_resends = RxPPacket.MAX_RESEND_LIMIT
while number_of_resends > 0:
print "Attempt #", (RxPPacket.MAX_RESEND_LIMIT - number_of_resends) + 1
rxp_socket.sendPacket(packet)
try:
address, packet = rxp_socket.receivePacket(RxPPacket.MAX_PACKET_SIZE)
print "Verifying packet"
if not packet.verifyPacket(): #invalid checksum
print("Incorrect checksum for sent data ack. Discarding packet")
number_of_resends -= 1
elif packet.header.syn_flag == 0 or packet.header.ack_flag == 0:
print("Not a SYN ACK! Discarding")
number_of_resends -= 1
else:
print("Received succesful SYN ACK")
return packet
except Exception as e:
if str(e) == "timed out":
print("Sending SYN timed out. " + str(number_of_resends - 1) + " attempts remaining")
number_of_resends -= 1
elif str(e).find("EOFError"):
print("Packet was mangled! resending!")
number_of_resends -= 1
else:
print "Grr"
print str(e)
raise e
raise RxPException("Sending SYN failed!")
return None
def sendSYNACK(rxp_socket):
print "Sending SYNACK!"
header = RxPPacketHeader()
header.src_port = rxp_socket.source_address[1]
header.dst_port = rxp_socket.destination_address[1]
header.syn_flag = 1
header.ack_flag = 1
packet = RxPPacket(header)
number_of_resends = RxPPacket.MAX_RESEND_LIMIT
while number_of_resends > 0:
rxp_socket.sendPacket(packet)
try:
address, packet = rxp_socket.receivePacket(RxPPacket.MAX_PACKET_SIZE)
if not packet.verifyPacket(): #invalid checksum
print("Incorrect checksum for sent data ack. Discarding packet")
number_of_resends -= 1
elif packet.header.syn_flag == 1 or packet.header.ack_flag == 0:
print("Not a ACK! Discarding")
number_of_resends -= 1
else:
print("Received succesful ACK to our SYNACK")
return packet
except Exception as e:
if str(e) == "timed out":
print("Sending SYN timed out. " + str(number_of_resends) + " resends remaining")
number_of_resends -= 1
else:
raise e
return None
