def Update_Window():
filename = "input.txt"
with open(filename) as f:
content = f.read()
global window
global window_size
global window_condition
global SEGMENT_SIZE
global sent_number_of_segment
global ofset
global updateWindow
global is_Update_Window_ACTIVE
while ofset < len(content):
if updateWindow == True:
lock.acquire()#lock
print "window acquiring..."
print "ofset = " + str(ofset)
print "len(content) = " + str(len(content))
if updateWindow == True:
window = []
window_condition = []
updateWindow = False
seq = 0
print "window updating..."
while True:
if ofset + SEGMENT_SIZE > len(content):
segment = content[ofset:]
window.append(ip_checksum(segment) + str(seq) + segment)
window_condition.append(1)
ofset = len(content)
break
else:
segment = content[ofset: ofset + SEGMENT_SIZE]
ofset += SEGMENT_SIZE
window.append(ip_checksum(segment) + str(seq) + segment)
window_condition.append(1)
seq += 1
#print window_condition
if len(window) == window_size:
break
time.sleep(0.01)
print "window releasing..."
lock.release()#unlock
print "Update_Window is finishing..."
is_Update_Window_ACTIVE = False
def Get_Packet(dest, listen):
global window
global window_condition
global update_Window_and_write_to_file_FLAG
global numberofActive_Get_Packet
global half
send_sock = socket(AF_INET, SOCK_DGRAM)
recv_sock = socket(AF_INET, SOCK_DGRAM)
recv_sock.bind(listen)
recv_sock.settimeout(20)
while True:
if sum(window_condition) != len(window_condition):
# lock.acquire()#lock
try:
message, address = recv_sock.recvfrom(1000)
message_list = message.split(' ', 2)
checksum = message[:2]
seq = int(message[2])
content = message[3:]
print "taken seq is " + str(seq)
print "-----------------------"
if ip_checksum(content) == checksum:
print window_condition
if window_condition[
seq] == -1: #implementing of window and pipelining taken packets displayed as 1 , waiting packets -1 on client
if (half == 0 and seq < len(window) / 2) or (
half == 1 and seq >= len(window) / 2):
window_condition[seq] = 1 # seq th is taken
window[seq] = content
checksum = ip_checksum(str(seq))
print "sending seq is " + str(seq)
send_sock.sendto(checksum + " " + str(seq), dest)
if half == 0 and sum(window_condition) == 0:
half = 1
if sum(window_condition) == len(window_condition):
update_Window_and_write_to_file_FLAG = True
half = 0
elif half == 0 and seq >= len(window) / 2:
checksum = ip_checksum(str(seq))
send_sock.sendto(checksum + " " + str(seq), dest)
print "sending seq is " + str(seq)
else:
seq = -1
checksum = ip_checksum(str(seq))
send_sock.sendto(checksum + " " + str(seq), dest)
print "half error sending seq is -1"
else:
checksum = ip_checksum(str(seq))
send_sock.sendto(checksum + " " + str(seq), dest)
print "sending seq is " + str(seq)
else:
seq = -1
checksum = ip_checksum(str(seq))
send_sock.sendto(checksum + " " + str(seq), dest)
print "checksum error sending seq is -1"
# lock.release()#unlock
except timeout:
print "timeout"
# lock.release()#unlock
break
numberofActive_Get_Packet -= 1
if numberofActive_Get_Packet <= 0:
update_Window_and_write_to_file_FLAG = True
def send(content, to):
checksum = ip_checksum(content)
send_sock.sendto(checksum + content, to)
recv_sock.bind(listen)
recv_sock.settimeout(1)
offset = 0
seq = 0
while offset < len(content):
if offset + SEGMENT_SIZE > len(content):
segment = content[offset:]
else:
segment = content[offset:offset + SEGMENT_SIZE]
offset += SEGMENT_SIZE
ack_received = False
while not ack_received:
send_sock.sendto(ip_checksum(segment) + str(seq) + segment, dest)
try:
message, address = recv_sock.recvfrom(4096)
except timeout:
print "Timeout"
else:
print message
checksum = message[:2]
ack_seq = message[5]
if ip_checksum(
message[2:]) == checksum and ack_seq == str(seq):
ack_received = True
seq = 1 - seq
recv_sock.bind(listen)
recv_sock.settimeout(1)
offset = 0
seq = 0
while offset < len(content):
if offset + SEGMENT_SIZE > len(content):
segment = content[offset:]
else:
segment = content[offset:offset + SEGMENT_SIZE]
offset += SEGMENT_SIZE
ack_received = False
while not ack_received:
send_sock.sendto(ip_checksum(segment) + str(seq) + segment, dest)
try:
message, address = recv_sock.recvfrom(4096)
except timeout:
print "Timeout"
else:
print message
checksum = message[:2]
ack_seq = message[5]
if ip_checksum(message[2:]) == checksum and ack_seq == str(seq):
ack_received = True
seq = 1 - seq
if __name__ == "__main__":
dest_addr = argv[1]
dest_port = int(argv[2])
dest = (dest_addr, dest_port)
listen_addr = argv[3]
listen_port = int(argv[4])
listen = (listen_addr, listen_port)
send_sock = socket(AF_INET, SOCK_DGRAM)
recv_sock = socket(AF_INET, SOCK_DGRAM)
recv_sock.bind(listen)
expecting_seq = 0
while True:
message, address = recv_sock.recvfrom(4096)
checksum = message[:2]
seq = message[2]
content = message[3:]
if ip_checksum(content) == checksum:
send("ACK" + seq, dest)
if seq == str(expecting_seq):
stdout.write(content)
expecting_seq = 1 - expecting_seq
else:
negative_seq = str(1 - expecting_seq)
send("ACK" + negative_seq, dest)
def send(content, to):
checksum = ip_checksum(content)
send_sock.sendto(checksum + content, to)
if __name__ == "__main__":
dest_addr = argv[1]
dest_port = int(argv[2])
dest = (dest_addr, dest_port)
listen_addr = argv[3]
listen_port = int(argv[4])
listen = (listen_addr, listen_port)
send_sock = socket(AF_INET, SOCK_DGRAM)
recv_sock = socket(AF_INET, SOCK_DGRAM)
recv_sock.bind(listen)
expecting_seq = 0
while True:
message, address = recv_sock.recvfrom(4096)
checksum = message[:2]
seq = message[2]
content = message[3:]
if ip_checksum(content) == checksum:
send("ACK" + seq, dest)
if seq == str(expecting_seq):
stdout.write(content)
expecting_seq = 1 - expecting_seq
else:
negative_seq = str(1 - expecting_seq)
send("ACK" + negative_seq, dest)
