连续重传滑动窗口协议实现代码

由于连续重传滑动窗口协议的实现可能有很多细节，因此这里只提供一个简单的示例代码作为参考。

发送方：

from socket import *

# 创建套接字和连接服务器
client_socket = socket(AF_INET, SOCK_STREAM)
client_socket.connect(('127.0.0.1', 8888))

# 定义窗口大小和起始序号
WINDOW_SIZE = 3
start_seq_num = 0

# 发送方发送数据的次数
send_times = 10

# 创建数据包
packets = [f"{i}".encode() for i in range(send_times)]

# 记录已发送但未收到确认的数据包
unacknowledged_packets = packets[:WINDOW_SIZE]

# 循环发送数据包
while packets:
    # 发送未确认的数据包
    for packet in unacknowledged_packets:
        client_socket.send(packet)
        print(f"send:{packet.decode()}")

    # 接收确认，如果有超时则重传
    for i in range(WINDOW_SIZE):
        try:
            # 设置接收超时时间
            client_socket.settimeout(1)
            data = client_socket.recv(1024)
        except timeout:
            # 超时了，重传未确认的数据包
            print(f"timeout, resend:{unacknowledged_packets[0].decode()}")
            client_socket.send(unacknowledged_packets[0])
            continue

        # 收到确认，从未确认列表中删除
        ack = int(data.decode())
        print(f"ack:{ack}")
        unacknowledged_packets.pop(0)

    # 发送下一个数据包
    if packets:
        packet = packets.pop(0)
        unacknowledged_packets.append(packet)

# 关闭套接字
client_socket.close()

接收方：

from socket import *
import time

# 创建套接字和绑定端口
server_socket = socket(AF_INET, SOCK_STREAM)
server_socket.bind(('127.0.0.1', 8888))
server_socket.listen(1)
print('The server is ready to receive')

# 接收方接收数据的次数
receive_times = 10

# 定义窗口大小和期望接收的下一个序号
WINDOW_SIZE = 3
expected_seq_num = 0

# 记录已收到但未确认的数据包
unacknowledged_packets = []

# 循环接收数据包并发送确认
while receive_times > 0:
    # 接收数据包
    connection_socket, address = server_socket.accept()
    data = connection_socket.recv(1024)
    print(f"receive:{data.decode()}")

    # 如果接收到的是期望的数据包，则发送确认
    seq_num = int(data.decode())
    if seq_num == expected_seq_num:
        expected_seq_num += 1
        ack = str(seq_num).encode()
        connection_socket.send(ack)
        print(f"send ack:{ack.decode()}")

        # 将已收到但未确认的数据包添加到列表中
        unacknowledged_packets.append(data)

        # 如果列表中的数据包个数达到窗口大小，则移动窗口并清空列表
        if len(unacknowledged_packets) == WINDOW_SIZE:
            unacknowledged_packets.clear()
            receive_times -= WINDOW_SIZE
            print(f"move window, receive_times:{receive_times}")
    # 如果接收到的不是期望的数据包，则丢弃并重新发送确认
    else:
        ack = str(expected_seq_num - 1).encode()
        connection_socket.send(ack)
        print(f"send ack:{ack.decode()}")

    # 延迟一段时间再关闭套接字，模拟网络延迟
    time.sleep(0.5)
    connection_socket.close()

# 关闭套接字
server_socket.close()