def serve_client(self, client, address):
total_time = datetime.now()
pkt = self.wait_for_request(client, address)
if not pkt:
return 1
file = SERVER_FOLDER + pkt.__get__('file')
if os.path.isfile(file): # if file is found on the server
pkt = Packet(status='found')
client.send(pkt.__dump__())
# Logic goes here
f = open(file=file, mode='rb')
data = f.read()
bits = len(data) * 8
# Build packet
packets = [
Packet(data=data[i: i + CHUNK_SIZE],
seq_num=i // CHUNK_SIZE)
for i in range(0, len(data), CHUNK_SIZE)
]
timeout_count = self.begin_transimission(
packets=packets, client=client, address=address)
total_time = (datetime.now() - total_time).total_seconds()
print('Sent ' + str(bits) + ' bits, in ' +
str(total_time) + ' secs, with ' +
str(timeout_count) + ' timeouts')
with open('GBNlog.txt', 'a') as log:
run_metrics = DELIMITER.decode() + '\n'
run_metrics += 'TYPE=GBN\n'
run_metrics += 'THROUGHPUT=' + \
str(bits / total_time) + '\n'
run_metrics += 'PACKET_LOSS=' + \
str(LOSS_PROBABILITY) + '\n'
log.write(run_metrics)
else: # if file not found, send not found packet
pkt = Packet(status='not_found')
client.send(pkt.__dump__())
print('Client disconnected, address: ', address)
client.close()
def begin_transimission(self, packets, client, address):
base = 0
self.send_window(packets, base, client, address)
client_timeout_count = CLIENT_TIMEOUT_TRIALS
while client_timeout_count:
if base >= len(packets):
break
end = base + WINDOW_SIZE
end = end if end < len(packets) else len(packets)
client.settimeout(TIME_OUT_SEC)
try: # Wait for response or timeout
res = client.recv(PACKET_SIZE)
if not res:
break
pkt = Packet(res=res)
pkt.__print__(from_address=address)
seq_num = int(pkt.__get__('seq_num'))
if base <= seq_num <= base + WINDOW_SIZE:
if pkt.__get__('ack') == '+':
client.settimeout(None)
free_slots = int(pkt.__get__('seq_num')) - base + 1
nEnd = end + free_slots
nEnd = nEnd if nEnd < len(packets) else len(packets)
new_pkts = packets[end:nEnd]
for pkt in new_pkts:
if randint(1, 100) > LOSS_PROBABILITY:
pkt.__print__(to_address=address)
client.send(pkt.__dump__())
else:
print(colored('Simulating Packet Loss: ' +
pkt.__get__('seq_num'), 'red'))
base += free_slots
else:
print(colored('Ack out of window, discard ' +
str(seq_num) + ' => from: ' + str(address),
color='blue'))
except timeout:
print(colored('Timeout, resending window. => to: ' +
str(address), color='red'))
self.send_window(packets, base, client, address)
client_timeout_count -= 1
# Retrun number of timeouts
return CLIENT_TIMEOUT_TRIALS - client_timeout_count
