def startReceiving(self):
"""# Function for receiving data"""
time.sleep(0.4)
# receive data from sender
data = self.connection.recv(576).decode()
# initialise total data received
total_data = ""
while data != "end":
print("\nSTATUS: FRAME RECEIVED")
# build frame from binary data string
frame = Frame.build(data)
# If frame has no error
if not frame.hasError():
print("STATUS: NO ERROR FOUND")
seqNo = frame.getSeqNo()
if self.seqNo == seqNo:
# extract data
data = frame.getData()
# print(data)
total_data += data
# update the sequence number of ACK
self.seqNo = (self.seqNo + 1) % 2
# send the corresponding ACK
self.sendAck()
print("STATUS: ACK SENT\n")
# if sequence number is not what is required, resend the previous ACK
else:
self.resendPreviousACK()
print("STATUS: ACK RESENT")
# discard erroneous frame
else:
print("STATUS: FRAME DISCARDED")
# wait and receive next frame
data = self.connection.recv(576).decode()
file = open(self.filename, 'w')
file.write(total_data)
file.close()
def receiveAck(self):
"""Function to handle acknowledgement receiving"""
time.sleep(0.2)
# loop until end of transmission
while (not self.eot) or (self.window_size > 0):
# if any frames were sent
if (self.window_size > 0):
# wait and receive acknowledgement and build frame from that
received = self.connection.recv(384).decode()
frame = Frame.build(received)
else:
continue
# if frame type is acknowledgement
if frame.getType() == 1:
# if frame has no error
if (frame.hasError() == False):
if self.isValidACK(frame.seqNo):
# Acquire lock for accessing window
self.lock.acquire()
# update the window front and window size according to the ackNo
while (self.front != frame.seqNo):
roundTripTime = time.time() - self.frame_timer[
self.front]
rttList.append(roundTripTime)
print("STATUS: FRAME", self.front,
"HAS REACHED SUCCESSFULLY\n")
self.front = (self.front + 1) % (MAX_WINDOW_SIZE +
1)
self.window_size -= 1
# Release window access lock
self.lock.release()
else:
print("STATUS: WRONG ACK")
else:
print("STATUS: ERRONEOUS ACK")
else:
print("STATUS: RECEIVED FRAME IS NOT AN ACK")
def startReceiving(self):
"""Function for receiving data"""
time.sleep(0.4)
# Wait for data and receive
data = self.connection.recv(576).decode()
total_data = ""
# If data-receiving hasn't ended yet
while data != "end":
# Build frame from binary data string
frame = Frame.build(data)
print("\nSTATUS: FRAME RECEIVED")
# If frame has no error
if not frame.hasError():
print("STATUS: NO ERROR FOUND")
# get frame sequence number
seqNo = frame.getSeqNo()
# if the ack no in received frame is equal to the expected
if self.seqNo == seqNo:
data = frame.getData()
# print(data)
total_data += data
self.seqNo = (self.seqNo + 1) % WINDOW_SIZE
self.sendAck()
print("STATUS: ACK SENT\n")
else:
self.resendPreviousACK()
print("STATUS: ACK RESENT")
# discard erroneous frame
else:
print("STATUS: FRAME DISCARDED")
# wait and receive next frame
data = self.connection.recv(576).decode()
file = open(self.filename, 'w')
file.write(total_data)
file.close()
def receiveAck(self):
"""Function to receive ACK frame"""
time.sleep(0.2)
# loop until end of transmission
while((not self.eot) or (self.frameSent)):
# if a frame is sent
if self.frameSent:
# wait and receive acknowledgement and build frame from that
received = self.connection.recv(384).decode()
if ("collision" not in received) and len(received) == 384:
# decode the received frame
frame = Frame.build(received)
# if frame type is acknowledgement, do the following
if frame.getType() == 1:
# if frame has no error, do the following
if(frame.hasError()==False):
# if ACK_NO == SEQ_NO then receive it, stop timer(set the internal flag of time-out event)
if frame.seqNo == self.seqNo:
# store the round trip time
self.receiveTime = time.time()
# evaluate the round trip time and append it to the list
roundTripTime = self.receiveTime - self.sentTime
rttList.append(roundTripTime)
print(self.name, "STATUS: DATA HAS REACHED SUCCESSFULLY\n")
# unset the frameSent flag
self.frameSent = False
else:
print(self.name, "STATUS: WRONG ACK")
else:
print(self.name, "STATUS: ERRONEOUS ACK")
else:
print(self.name, "STATUS: RECEIVED FRAME IS NOT AN ACK")
else:
print (self.name, "STATUS: Collision detected")
self.collision += 1
self.sentTime=time.time()
def receiveAckOrNak(self):
"""Function to handle acknowledgement receiving"""
time.sleep(0.2)
# loop until end of transmission
while (not self.eot) or (self.window_size > 0):
# if any frames were sent
if (self.window_size > 0):
# wait and receive acknowledgement and build frame from that
received = self.connection.recv(384).decode()
frame = Frame.build(received)
else:
continue
# if frame type is ACK
if frame.getType() == 1:
# if frame has no error
if (frame.hasError() == False):
if self.validACK(frame.seqNo):
# Acquire lock for accessing window
self.lock.acquire()
# update the window front and window size according to the ackNo
while (self.front != frame.seqNo):
# Store round-trip time into the list
roundTripTime = time.time() - self.frameTimer[
self.front]
rttList.append(roundTripTime)
print("STATUS: FRAME", self.front,
"HAS REACHED SUCCESSFULLY\n")
self.current_window[self.front] = 0
self.front = ((self.front + 1) %
MAX_SEQUENCE_NUMBER)
self.window_size -= 1
# release window access lock
self.lock.release()
else:
print("STATUS: WRONG ACK")
else:
print("STATUS: ERRONEOUS ACK")
# if frame type is NAK
elif frame.getType() == 2:
# if frame has no error
if not frame.hasError():
# if requested sequence number is within window
if self.validACK(frame.seqNo):
# acquire lock for accessing window
self.lock.acquire()
# resend the requested frame
if (self.current_window[frame.seqNo] != 0):
self.connection.send(
str.encode(self.current_window[
frame.seqNo].toBinaryString(46)))
print("STATUS: FRAME", frame.seqNo,
"RESENT from NAK")
self.frameTimer[frame.seqNo] = time.time()
self.totalFrameCount += 1
# release window access lock
self.lock.release()
else:
print("STATUS: WRONG NAK")
else:
print("STATUS: ERRONEOUS NAK")
else:
print("STATUS: RECEIVED FRAME IS NOT AN ACK")
def startReceiving(self):
"""Function for receiving frames"""
time.sleep(0.4)
ACKresendingThread = threading.Thread(target=self.resendPreviousACK)
ACKresendingThread.start()
# wait for data and receive
data = self.connection.recv(576).decode()
total_data = ""
while data != "end":
# build frame from binary data string
frame = Frame.build(data)
print("\nSTATUS: FRAME RECEIVED")
if not frame.hasError():
print("STATUS: NO ERROR FOUND")
seqNo = frame.getSeqNo()
# if frame other than first one got, send NAK
if (seqNo != self.front and self.nakSent == False):
self.sendNak()
self.nakSent = True
# if seq no within the window accept it
if (self.validSEQ(seqNo) and self.filled_up[seqNo] == False):
self.filled_up[seqNo] = True
self.window[seqNo] = frame.getData()
print(frame.getData())
# take the received data sequentially into the final data string
# update the front, end of the window accordingly (also update flags)
while (self.filled_up[self.front] == True):
total_data += self.window[self.front]
self.filled_up[self.front] = False
self.front = (self.front + 1) % MAX_SEQUENCE_NUMBER
self.end = (self.end + 1) % MAX_SEQUENCE_NUMBER
self.ackSent = True
print("STATUS: FRAME RECEIVED SUCCESSFULLY")
# if sequential frame received, send acknowledgement
if (self.ackSent):
self.sendAck()
self.ackSent = False
self.nakSent = False
# discard erroneous frame
else:
print("STATUS: ERRONEOUS FRAME")
# wait and receive next frame
data = self.connection.recv(576).decode()
# stop the resending-acknowledgement thread
self.eot = True
ACKresendingThread.join()
# write the whole data into file
file = open(self.filename, 'w')
file.write(total_data)
file.close()