UDP ​

from socket import *

tcp_socket = socket(AF_INET, SOCK_STREAM)  # 创建跨主机TCP socket
udp_socket = socket(AF_INET, SOCK_DGRAM)  # 创建跨主机UDP socket

from socket import *

# 客户端
udp_client = socket(AF_INET, SOCK_DGRAM)  # 创建跨主机UDP socket
msg = "测试消息".encode("gb2312")  # 处理编码问题
# msg = b"test message"
udp_client.sendto(msg, ("192.168.0.200", 8080))  # 发送数据
udp_client.close()

# 服务器
udp_server = socket(AF_INET, SOCK_DGRAM)
udp_server.bind(('', 8080))  # ''表示绑定本机所有可用IP，8080为绑定端口
msg,(host,port) = udp_client.recvfrom(1024)  # 阻塞等待接收消息。1024表示每次接收最大字节数
print(msg.decode("gb2312"))
udp_server.close()

from socket import *

def main():
    echo = socket(AF_INET, SOCK_DGRAM)
    echo.bind(('', 8080))
    while True:
        msg, src = echo.recvfrom(1024)
        echo.sendto(msg, src)
        print("received %s from %s" % (msg, src))

    echo.close()


if __name__ == "__main__":
    main()

from socket import *
from threading import Thread
from time import ctime


def receive():
    while True:
        msg, (host, port) = skt.recvfrom(1024)
        print("%s:%d %s\t%s" % (host, port, ctime(), msg.decode()))


def send(addr):
    while True:
        msg = input().encode()
        skt.sendto(msg, addr)


skt: socket = None


def main():
    global skt
    skt = socket(AF_INET, SOCK_DGRAM)
    skt.bind(('', 8080))

    ip = input("target ip:")
    port = int(input("target port:"))

    Thread(target=receive).start()
    Thread(target=send, args=(ip, port)).start()


if __name__ == '__main__':
    main()

from socket import *

bd = socket(AF_INET, SOCK_DGRAM)
bd.setsockopt(SOL_SOCKET, SO_BROADCAST, 1)  # 设置广播
bd.sendto("test broadcast".encode(), ("<broadcast>", 8080))  # 发送到广播地址
bd.close()

from struct import pack

pack("!H8sb5sb",1,"test.txt",0,"octet",0)

"""
pack函数第一个参数为数据包格式，后面各参数填充各位置

1. '!'开头表示此为网络数据包,使用大端组织数据
2. 'H'表示整数占位2B，第二个参数1会占用2B
1. 's'表示字符占位1B，8s表示第三个参数test.txt占用8B
4. 'b'表示整数占位1B，第四个参数0占用1B
5. '5sb'分别为最后octet和0两个参数占位5B和1B
"""

from socket import *
from struct import pack, unpack


def download(file):
    rrq = pack("!H{}sb5sb".format(len(file)), 1, file.encode(), 0, b"octet", 0)  # 构建下载请求
    udp.sendto(rrq, (ip, 69))  # 发送下载文件请求

    chunk = 0  # 本地模块号
    recv_file = None

    while True:
        recv_data, recv_addr = udp.recvfrom(1024)
        recv_len = len(recv_data)
        code_chunk = unpack("!HH", recv_data[:4])
        code = code_chunk[0]  # 操作码
        current_chunk = code_chunk[1]  # 模块号

        if code == 3:  # 数据包
            if current_chunk == 1:  # 如果是第一次接收到数据，那么就创建文件
                recv_file = open(file, "ab")

            if chunk + 1 == current_chunk:  # 校验模块号
                recv_file.write(recv_data[4:])
                chunk += 1
                print("第{}次接收到数据 {} byte(s)".format(chunk, recv_len))
                ack = pack("!HH", 4, chunk)
                udp.sendto(ack, recv_addr)

            if recv_len < 516:  # 判断是否完成
                recv_file.close()
                print('文件下载成功')
                break

        elif code == 5:  # 错误应答
            (error_msg,) = unpack("!{}s".format(recv_len - 4), recv_data[4:recv_len])
            print("error occured at chunk-{}.error message:{}".format(current_chunk, error_msg.decode()))
            break


def upload(file):
    wrq = pack("!H{}sb5sb".format(len(file)), 2, file.encode(), 0, b"octet", 0)  # 构建上传请求
    udp.sendto(wrq, (ip, 69))  # 发送下载上传请求

    chunk = 1  # 本地模块号
    send_file = None

    while True:
        recv_data, recv_addr = udp.recvfrom(1024)
        code, current_chunk = unpack("!HH", recv_data[:4])

        if code == 4:  # ACK
            if current_chunk == 0:  # 如果是第一次，那么就打开文件
                send_file = open(file, "rb")

            if current_chunk + 1 == chunk:  # 校验模块号
                data = send_file.read(512)  # 读取 512 byte数据
                send_data = pack("!HH{}s".format(len(data)), 3, chunk, data)
                udp.sendto(send_data, recv_addr)  # 打包发送数据
                print("第{}次数据已发送 {} byte(s)".format(chunk, len(send_data)))
                chunk += 1

                if len(data) <= 0:  # 判断文件是否读取完成
                    send_file.close()
                    print("文件上传完成...")
                    break

        elif code == 5:  # 错误应答
            recv_len = len(recv_data)
            (error_msg,) = unpack("!{}s".format(recv_len - 4), recv_data[4:recv_len])
            print("error occured at chunk-{}.error message:{}".format(current_chunk, error_msg.decode()))
            break


ip = ''
udp = None


def main():
    global ip, udp

    ip = input("please type the hostname of TFTP server:\n")
    udp = socket(AF_INET, SOCK_DGRAM)  # 创建udp套接字
    udp.bind(('', 8080))

    while True:
        act = int(input("please choose what to do?\n1:download\n2:upload\n3:quit\n"))
        if act == 1:
            file = input("type the name of the file you wanna download...\n")
            download(file)
        elif act == 2:
            file = input("type the name of the file you wanna upload...\n")
            upload(file)
        elif act == 3:
            break

    udp.close()


if __name__ == '__main__':
    main()