fix: benerin go_back_n

const.py

@@ -6,7 +6,8 @@ class FLAGS:
   ACK = 0b0001_0000
 
 WINDOWS_SIZE = 16
-SERVER_TIMEOUT = CLIENT_TIMEOUT = 5
+CLIENT_TIMEOUT = 5
+SERVER_TIMEOUT = CLIENT_TIMEOUT / 2
 
 HEADER_SIZE = 12  # bytes
 MAX_PAYLOAD_SIZE = 32768  # bytes

server.py

@@ -21,6 +21,7 @@ def send_handler(
   sequence_base = 0
   sequence_max = WINDOWS_SIZE + 1
   ack_number = -1
+  go_back = False
 
   def update_ack():
     nonlocal ack_number
@@ -41,10 +42,8 @@ def send_handler(
     # terima ACK
     update_ack()
 
-    can_send = sequence_base <= sequence_current <= sequence_max
+    can_send = sequence_base <= sequence_current < sequence_max
     init_time = perf_counter()
-    i = 0
-    max_try = 3
     while not can_send:
       # Nunggu dapet ACK sampe timeout
       # Kalo timeout belom go_back_n
@@ -54,16 +53,17 @@ def send_handler(
       update_ack()
       # Tandai request udah di-consume
       event.clear()
-      can_send = sequence_base <= sequence_current <= sequence_max
+      can_send = sequence_base <= sequence_current < sequence_max
 
       # masih ga bisa ngirim dan waktu habis
       if not can_send and perf_counter() - init_time >= SERVER_TIMEOUT:
-        if i >= max_try:
-          print(f'Connection with client {client[0]}:{client[1]} has timed out after {max_try} tries. Giving up.')
-          return
+        packets.go_back_n(WINDOWS_SIZE + 1)
+        go_back = True
+        break
 
-        packets.go_back_n(WINDOWS_SIZE)
-        i += 1
+    if go_back:
+      go_back = False
+      continue
 
     print(f'Sending packet {sequence_current} to {client[0]}:{client[1]}')
     sock.sendto(packet, client)