UDP 通信流程_udp通信过程-CSDN博客参考来源

UDP 通信流程_udp通信过程-CSDN博客

这里移植到windows 上 ，使用 devc++ 开发。 

服务端代码

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <winsock2.h>int main()
{WORD sockVersion = MAKEWORD(2, 2);WSADATA data;if (WSAStartup(sockVersion, &data) != 0){return 0;}// 1. 创建通信的套接字SOCKET fd = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);if (fd == INVALID_SOCKET){printf("无效的 socket !");return 0;}// 2. 通信的套接字和本地的IP与端口绑定struct sockaddr_in addr;addr.sin_family = AF_INET;addr.sin_port = htons(9999);    // 大端addr.sin_addr.s_addr = htonl(INADDR_ANY);  // 0.0.0.0int ret = bind(fd, (struct sockaddr*)&addr, sizeof(addr));if(ret == -1){perror("bind");exit(0);}char buf[1024];struct sockaddr_in cliaddr;int len = sizeof(cliaddr);// 3. 通信while(1){// 接收数据memset(buf, 0, sizeof(buf));int rlen = recvfrom(fd, buf, sizeof(buf), 0, (struct sockaddr*)&cliaddr, &len);printf("客户端的IP地址: %s, 端口: %d\n",inet_ntoa(cliaddr.sin_addr),ntohs(cliaddr.sin_port));printf("客户端say: %s\n", buf);// 回复数据// 数据回复给了发送数据的客户端sendto(fd, buf, rlen, 0, (struct sockaddr*)&cliaddr, sizeof(cliaddr));}close(fd);return 0;
}

客户端代码

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <winsock2.h>int main()
{WORD sockVersion = MAKEWORD(2, 2);WSADATA data;if (WSAStartup(sockVersion, &data) != 0){return 0;}// 1. 创建通信的套接字SOCKET fd = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);if (fd == INVALID_SOCKET){printf("无效的 socket !");return 0;}// 2. 通信的套接字和本地的IP与端口绑定struct sockaddr_in addr;addr.sin_family = AF_INET;addr.sin_port = htons(9999);    // 大端
//	addr.sin_addr.s_addr = htonl(INADDR_BROADCAST);  // 255.255.255.255 广播 char loa[16] = "127.0.0.1";						// 这是指定 IP发送数据 addr.sin_addr.S_un.S_addr = inet_addr(loa);				// 加入指定 IP char buf[1024];char ipbuf[64];int num = 0;// 2. 通信while(1){sprintf(buf, "hello, udp %d....\n", num++);// 发送数据, 数据发送给了服务器sendto(fd, buf, strlen(buf)+1, 0, (struct sockaddr*)&addr, sizeof(addr));// 接收数据memset(buf, 0, sizeof(buf));recvfrom(fd, buf, sizeof(buf), 0, NULL, NULL);printf("服务器say: %s\n", buf);sleep(1);}close(fd);return 0;
}