c语言实现简单的udp传输（ c/s 模型）

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客户端代码：

/*client.c*/#include <stdio.h>#include <sys/types.h>#include <sys/socket.h>#include <netinet/in.h>#include <string.h>#include <arpa/inet.h>#define MAXBUF 256int main(int argc, char const *argv[]){int s = 0;int n = 0;int reuse = 1;int port = 1987;struct sockaddr_in srv;char buf[MAXBUF] = {0};/*解析参数*/if (argc != 2){printf("Usage:%s ServerIP\n", argv[0]);return -1;}bzero(&srv, sizeof(srv));srv.sin_family = PF_INET;srv.sin_addr.s_addr = inet_addr(argv[1]);srv.sin_port = htons(port);/*创建 UDP 套节字*/s = socket(AF_INET, SOCK_DGRAM, 0);if(s<0){perror("socket");return -1;}while(1){memset(buf, 0, MAXBUF);/*读取用户输入到buf中*/fgets(buf, MAXBUF, stdin);/*通过套节字 s 向服务器发送数据*/if ((n = sendto(s, buf, strlen(buf), 0, (struct sockaddr *) &srv, sizeof(struct sockaddr))) < 0){perror("sendto");return -1;}else{printf("send to %s(port=%d) len %d:%s\n", argv[1], port, n, buf);}}}

服务器端代码：

/*server.c*/#include <stdio.h>#include <sys/types.h>#include <sys/socket.h>#include <netinet/in.h>#include <string.h>#include <arpa/inet.h>#define MAXBUF 256int main(int argc, char const *argv[]){int s = 0;int n = 0;int reuse = 1;int cli_len = sizeof(struct sockaddr);int port = 1987;char buf[MAXBUF] = {0};struct sockaddr_in addr, cli;/*初始化本地监听端口信息*/bzero(&addr, sizeof(addr));addr.sin_family = PF_INET;addr.sin_addr.s_addr = INADDR_ANY;addr.sin_port = htons(port);/*创建UDP套节字*/s = socket(AF_INET, SOCK_DGRAM, 0);if (s<0){perror("socket");return -1;}/*允许端口复用*/setsockopt(s, SOL_SOCKET, SO_REUSEADDR, &reuse, sizeof(reuse));/*绑定指定端口*/if (bind(s, (struct sockaddr *)&addr, sizeof(addr)) < 0){perror("bind");return -1;}while(1){memset(buf, 0, MAXBUF);/*从套节字s中读取数据*/n = recvfrom(s, buf, MAXBUF, 0, (struct sockaddr *)&cli, &cli_len);if(n<0){perror("recvfrom");return -1;}else{printf("receive msg from %s(port=%d) len %d: %s\n",inet_ntoa(cli.sin_addr), port, n, buf);}}return 0;}

编译命令：

客户端：

gcc client.c -o client./client 127.0.0.1

服务端：

gcc server.c -o server./server

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