添加 chat.py

chat.py

@@ -0,0 +1,68 @@
+import socket
+import threading
+import protocol
+
+LOCAL_PORT = 9000
+TIMEOUT = 2
+
+class StopWaitChat:
+    def __init__(self, local_port, peer_addr):
+        self.sock = socket.socket(
+            socket.AF_INET6,
+            socket.SOCK_DGRAM
+        )
+        self.sock.bind(("::", local_port))
+        self.sock.settimeout(TIMEOUT)
+
+        self.peer_addr = peer_addr
+        self.send_seq = 0
+        self.recv_seq = 0
+
+    def sender(self):
+        while True:
+            msg = input(">> ").encode()
+            pkt = protocol.make_packet(
+                self.send_seq,
+                protocol.TYPE_DATA,
+                msg
+            )
+
+            while True:
+                self.sock.sendto(pkt, self.peer_addr)
+                try:
+                    data, _ = self.sock.recvfrom(1024)
+                    seq, ptype, _ = protocol.parse_packet(data)
+                    if ptype == protocol.TYPE_ACK and seq == self.send_seq:
+                        self.send_seq ^= 1
+                        break
+                except socket.timeout:
+                    print("[timeout] retransmit")
+
+    def receiver(self):
+        while True:
+            data, addr = self.sock.recvfrom(1024)
+            seq, ptype, payload = protocol.parse_packet(data)
+
+            if ptype == protocol.TYPE_DATA:
+                if seq == self.recv_seq:
+                    print("\npeer:", payload.decode())
+                    self.recv_seq ^= 1
+                ack = protocol.make_packet(seq, protocol.TYPE_ACK)
+                self.sock.sendto(ack, addr)
+
+if __name__ == "__main__":
+    import sys
+    if len(sys.argv) != 3:
+        print("用法: python3 chat.py <对方IPv6地址> <对方端口>")
+        exit(1)
+
+    peer_ip = sys.argv[1]
+    peer_port = int(sys.argv[2])
+
+    chat = StopWaitChat(
+        LOCAL_PORT,
+        (peer_ip, peer_port)
+    )
+
+    threading.Thread(target=chat.receiver, daemon=True).start()
+    chat.sender()