def GBN(self):
# Requesting File From Server
current_seq = 0
pkt = create_udp_packet(self.port_number, self.server_port, 0,
self.file_name)
self.client_sock.sendto(pkt, (localhost, self.server_port))
print("CLIENT sent file request.")
file_data = bytearray()
ackd_pkts = []
while True:
# Receive 256 Bytes + 10 Bytes (Header) of data from server.
data = self.client_sock.recv(256 + 10)
if data == b'EOF' or not data:
break
# Extracting data from packet.
handler_port = int.from_bytes(data[:2], 'big')
dest_port = int.from_bytes(data[2:4], 'big')
msg_len = int.from_bytes(data[4:6], 'big')
checksum = int.from_bytes(data[6:8], 'big')
pkt_seq = int.from_bytes(data[8:10], 'big')
# If the data is invalid, ignore it.
if not validate_checksum(data):
continue
print("Receiving", pkt_seq)
if pkt_seq == current_seq:
ack_pkt = create_ack_packet(pkt_seq)
if random.random() < 0.95:
self.client_sock.sendto(ack_pkt, (localhost, handler_port))
print("Sending ack", pkt_seq)
# check with window size
current_seq += 1
ackd_pkts.append(data[10:])
else:
if current_seq > 0:
ack_pkt = create_ack_packet(current_seq - 1)
if random.random() < 0.95:
self.client_sock.sendto(ack_pkt,
(localhost, handler_port))
print("Sending ack", current_seq - 1)
for s in ackd_pkts:
file_data.extend(s)
ackd_pkts.clear()
with open(os.path.realpath(self.file_name), 'wb') as file:
file.write(file_data)
self.client_sock.close()
def rdt30(self):
pkt = create_udp_packet(self.client_sock.getsockname()[1],
self.server_port, 0, self.file_name, False)
self.client_sock.sendto(pkt, (localhost, self.server_port))
print("CLIENT sent file request.")
full_data = bytearray()
# Expected seq number
seq_no = 0
ack_pkt = None
while True:
data = self.client_sock.recv(256 + 10)
# Indication that the file is fully sent by the server by sending EOF signal or data is corrupted.
if data == b'EOF' or not data:
break
# Extracting the data from packet received from server
handler_port = int.from_bytes(data[:2], 'big')
dest_port = int.from_bytes(data[2:4], 'big')
msg_len = int.from_bytes(data[4:6], 'big')
checksum = int.from_bytes(data[6:8], 'big')
pkt_seq = int.from_bytes(data[8:10], 'big')
if not validate_checksum(data) or seq_no != pkt_seq:
if ack_pkt is not None:
if random.random() < 0.95:
print("CLIENT resending ACK",
int.from_bytes(ack_pkt, 'big'))
self.client_sock.sendto(ack_pkt,
(localhost, handler_port))
continue
if validate_checksum(data) and pkt_seq == seq_no:
print("CLIENT received packet with sequence", pkt_seq)
full_data.extend(data[10:])
ack_pkt = create_ack_packet(seq_no)
if random.random() < 0.95:
print("CLIENT resending ACK",
int.from_bytes(ack_pkt, 'big'))
self.client_sock.sendto(ack_pkt, (localhost, handler_port))
print("CLIENT sent ACK", seq_no)
seq_no = seq_no ^ 1
print("CLIENT expecting packet", seq_no)
data = None
# Write file's data on HDD from bytearray.
with open(os.path.realpath(self.file_name), 'wb') as f:
f.write(full_data)
self.client_sock.close()
def selective_repeat(self):
# Requesting File From Server
pkt = create_udp_packet(self.port_number, self.server_port, 0, self.file_name)
self.client_sock.sendto(pkt, (localhost, self.server_port))
print("CLIENT sent file request.")
file_data = bytearray()
window = Window(self.window_size)
while True:
# Receive 256 Bytes + 10 Bytes (Header) of data from server.
data = self.client_sock.recv(256+10)
# Break when EOF is reached.
if data == b'EOF' or not data:
break
# Extracting data from packet.
handler_port = int.from_bytes(data[:2], 'big')
dest_port = int.from_bytes(data[2:4], 'big')
msg_len = int.from_bytes(data[4:6], 'big')
checksum = int.from_bytes(data[6:8], 'big')
pkt_seq = int.from_bytes(data[8:10], 'big')
# If the data is invalid, ignore it.
if not validate_checksum(data):
continue
print("Receving", pkt_seq)
# Create and acknowledgment packet with the sequence number received
# And successfully send it with 95% chance.
ack_pkt = create_ack_packet(pkt_seq)
if random.random() < 0.95:
self.client_sock.sendto(ack_pkt, (localhost, handler_port))
print(window.current_c())
# Only buffer the data that in the current window frame.
# This is becuase that you should ignore packets received that
# Client has already buffered, however you still need to send an
# ACK for those.
if pkt_seq in window:
window.buffer_data(data[10:], pkt_seq)
# Also, Instead of dealing with the base sequence number, Just
# Buffering every packet and then iterate the current window
# And breaking when we find the very first unacked packet
# is a better option.
for s in window.current_c():
if s.acked:
file_data.extend(s.data)
window.update_base()
else:
break
with open(os.path.realpath(self.file_name), 'wb') as file:
file.write(file_data)
self.client_sock.close()