def receiver():
# receive data from server (data, addr)
global LASTACK
global EXIT_THREAD
global SEND_BUF
global SEND_BUF_SEQ
global TIMER
global EXPIRED
recv_buf = []
toDisplay = -1
time.sleep(0.01)
while EXIT_THREAD != 1:
try:
d = s.recvfrom(64)
recv_buf.append(d)
# print "Receiving.."
except:
# print "error here"
pass
for datagram in recv_buf:
errno, seq_no = util.parseDatagram(datagram[0], 1)
if errno == 0:
if len(SEND_BUF_SEQ) > 0 and (seq_no >= SEND_BUF_SEQ[0]):
# print "ACK #" + str(seq_no)
# print SEND_BUF_SEQ
diff = seq_no - SEND_BUF_SEQ[0]
THREAD_LOCK.acquire()
for tc in range(diff):
SEND_BUF.pop(0)
SEND_BUF_SEQ.pop(0)
THREAD_LOCK.release()
recv_buf.pop(0)
TIMER.cancel()
# TIMER.join()
THREAD_LOCK.acquire()
EXPIRED = 0
TIMER = threading.Timer(TIMER_SET, timerHandler)
TIMER.start()
THREAD_LOCK.release()
LASTACK = seq_no - 1
elif errno == 1:
print "Unmatched checksum, datagram is corrupted"
elif errno == 2:
print "Unmatched indicator, datagram is corrupted"
def receiver():
# receive data from server (data, addr)
global LASTACK
global EXIT_THREAD
global SEND_BUF
global SEND_BUF_SEQ
global TIMER
global EXPIRED
recv_buf = []
toDisplay = -1
time.sleep(0.01)
while EXIT_THREAD != 1:
try:
d = s.recvfrom(64)
recv_buf.append(d)
# print "Receiving.."
except:
# print "error here"
pass
for datagram in recv_buf:
errno, seq_no = util.parseDatagram(datagram[0], 1)
if errno == 0:
if len(SEND_BUF_SEQ) > 0 and (seq_no >= SEND_BUF_SEQ[0]):
# print "ACK #" + str(seq_no)
# print SEND_BUF_SEQ
diff = seq_no - SEND_BUF_SEQ[0]
THREAD_LOCK.acquire()
for tc in range(diff):
SEND_BUF.pop(0)
SEND_BUF_SEQ.pop(0)
THREAD_LOCK.release()
recv_buf.pop(0)
TIMER.cancel()
# TIMER.join()
THREAD_LOCK.acquire()
EXPIRED = 0
TIMER = threading.Timer(TIMER_SET, timerHandler)
TIMER.start()
THREAD_LOCK.release()
LASTACK = seq_no - 1
elif errno == 1:
print "Unmatched checksum, datagram is corrupted"
elif errno == 2:
print "Unmatched indicator, datagram is corrupted"
def FTPReceiver(s, p=0.05):
global P # Probability of packet loss
P = p
# Initialize the Sequence number
lastSEQNO = -1
max_seq_no = -1
firstTime = True
MSS = 0
oldSEQNO = -1
buffer=""
while 1:
packet = s.recvfrom(1100)
data = packet[0]
serverAddr = packet[1]
if not data:
continue
if firstTime:
MSS = len(data) - 64
firstTime = False
# Simulate a random drop process
randomNum = random.random()
# print randomNum
if randomNum <= P:
if oldSEQNO != lastSEQNO:
oldSEQNO = lastSEQNO
print "Packet loss, sequence num = " + str((lastSEQNO + 1) * MSS)
continue
errno, seq_no, dataText = util.parseDatagram(data, 0)
# print "SEQ_NO:" + str(seq_no)
# print "LAST_ACK:" + str(lastSEQNO)
if seq_no > max_seq_no:
max_seq_no = seq_no
if errno == 0:
if seq_no == lastSEQNO + 1:
lastSEQNO = seq_no
buffer+=dataText
reply = util.buildHeader(lastSEQNO+1, '', 1)
s.sendto(reply, serverAddr)
elif errno == 1:
print "Unmatched checksum, datagram is corrupted"
break
elif errno == 2:
print "Unmatched indicator, datagram is corrupted"
break
else:
if seq_no == lastSEQNO + 1:
lastSEQNO = seq_no
reply = util.buildHeader(lastSEQNO+1, '', 3)
s.sendto(reply, serverAddr)
if max_seq_no == lastSEQNO:
print "Transfer finished!"
print "SEQ_NO "+str((lastSEQNO+1)*MSS)+ " is sent!"
break
s.close()
return buffer
def FTPReceiver(s, p=0.05):
global P # Probability of packet loss
P = p
# Initialize the Sequence number
lastSEQNO = -1
max_seq_no = -1
firstTime = True
MSS = 0
oldSEQNO = -1
buffer = ""
while 1:
packet = s.recvfrom(1100)
data = packet[0]
serverAddr = packet[1]
if not data:
continue
if firstTime:
MSS = len(data) - 64
firstTime = False
# Simulate a random drop process
randomNum = random.random()
# print randomNum
if randomNum <= P:
if oldSEQNO != lastSEQNO:
oldSEQNO = lastSEQNO
print "Packet loss, sequence num = " + str(
(lastSEQNO + 1) * MSS)
continue
errno, seq_no, dataText = util.parseDatagram(data, 0)
# print "SEQ_NO:" + str(seq_no)
# print "LAST_ACK:" + str(lastSEQNO)
if seq_no > max_seq_no:
max_seq_no = seq_no
if errno == 0:
if seq_no == lastSEQNO + 1:
lastSEQNO = seq_no
buffer += dataText
reply = util.buildHeader(lastSEQNO + 1, '', 1)
s.sendto(reply, serverAddr)
elif errno == 1:
print "Unmatched checksum, datagram is corrupted"
break
elif errno == 2:
print "Unmatched indicator, datagram is corrupted"
break
else:
if seq_no == lastSEQNO + 1:
lastSEQNO = seq_no
reply = util.buildHeader(lastSEQNO + 1, '', 3)
s.sendto(reply, serverAddr)
if max_seq_no == lastSEQNO:
print "Transfer finished!"
print "SEQ_NO " + str((lastSEQNO + 1) * MSS) + " is sent!"
break
s.close()
return buffer
