UDP小实验

news/2025/2/13 10:39:07/

需求：
```csharp
如果客户端发送的消息是 "time\n"，服务器会获取当前的本地时间，
并将其格式化为 YYYY-MM-DD HH:MM:SS 的字符串发送给客户端。
如果客户端发送的消息不是 "time\n"，服务器会返回 "cmd error!" 给客户端。

server.c

/*===============================================
*   文件名称：server.c
*   创 建 者：
*   创建日期：2025年02月10日
*   描    述：
================================================*/
#include <stdio.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <string.h>
#include <stdlib.h>
#include <arpa/inet.h>
#include <netinet/in.h>
#include <unistd.h>
#include <time.h>
int main(int argc, char *argv[])
{ time_t t;struct tm *mt = NULL;int sockfd = socket(AF_INET,SOCK_DGRAM,0);if(sockfd < 0){perror("socket");exit(-1);}struct sockaddr_in saddr;saddr.sin_family = AF_INET;saddr.sin_port = htons(8888);saddr.sin_addr.s_addr = inet_addr("192.168.6.44");int s_len = sizeof(saddr);int ret = bind(sockfd,(struct sockaddr *)&saddr,s_len);if(ret < 0){perror("bind");exit(-1);}struct sockaddr_in caddr;int c_len = sizeof(caddr);memset(&caddr,0,sizeof(caddr));char buf[64] = {0};while(1){memset(buf,0,64);ret = recvfrom(sockfd,buf,64,0,(struct sockaddr *)&caddr,&c_len);if(ret < 0){perror("recvfrom");exit(-1);}printf("ip:%s --- recv %d bytes:%s\n",inet_ntoa(caddr.sin_addr),ret,buf);if(strcmp(buf,"time\n") == 0){memset(buf,0,64);time(&t);mt = localtime(&t);sprintf(buf,"%d-%d-%d %02d:%02d:%02d",mt->tm_year+1900,mt->tm_mon+1,mt->tm_mday,mt->tm_hour,mt->tm_min,mt->tm_sec);sendto(sockfd,buf,64,0,(struct sockaddr *)&caddr,c_len);}else{strcpy(buf, "cmd error!");sendto(sockfd, buf, 64, 0, (struct sockaddr *)&caddr, c_len);}}close(sockfd);return 0;
}

client.c

/*===============================================
*   文件名称：client.c
*   创 建 者：
*   创建日期：2025年02月10日
*   描    述：
================================================*/
#include <stdio.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <string.h>
#include <stdlib.h>
#include <arpa/inet.h>
#include <netinet/in.h>
int main(int argc, char *argv[])
{ int sockfd = socket(AF_INET,SOCK_DGRAM,0);if(sockfd < 0){perror("socket");exit(-1);}struct sockaddr_in saddr,caddr;saddr.sin_family = AF_INET;saddr.sin_port = htons(8888);saddr.sin_addr.s_addr = inet_addr("192.168.6.44");int s_len = sizeof(saddr);int c_len = sizeof(caddr);memset(&caddr,0,sizeof(caddr));char buf[64] = {0};while(1){memset(buf,0,64);fgets(buf,64,stdin);int ret = sendto(sockfd,buf,64,0,(struct sockaddr *)&saddr,s_len);if(ret < 0){perror("sendto");exit(-1);}memset(buf,0,64);recvfrom(sockfd, buf, 64, 0, (struct sockaddr *)&caddr, &c_len);printf("%s\n", buf);}close(sockfd);return 0;
}