#include <stdlib.h>
#include <stdio.h>
#include <errno.h>
#include <string.h>
#include <unistd.h>
#include <netdb.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <sys/types.h>
#include <arpa/inet.h>
#define SERVER_PORT 8888
#define MAX_MSG_SIZE 1024
void udps_respon(int sockfd)
{
struct sockaddr_in addr;
int addrlen,n;
char msg[MAX_MSG_SIZE];
char addr_p[20];
while(1)
{ /* 从网络上读,并写到网络上 */
bzero(msg,sizeof(msg)); // 初始化,清零
addrlen = sizeof(struct sockaddr);
n=recvfrom(sockfd,msg,MAX_MSG_SIZE,0,(struct sockaddr*)&addr,&addrlen); // 从客户端接收消息
msg[n]=0;
/* 显示服务端已经收到了信息 */
inet_ntop(AF_INET, &addr.sin_addr, addr_p, sizeof(addr_p));
printf("Client Ip is %s, port is %d\n",addr_p,ntohs(addr.sin_port));
sendto(sockfd,msg,strlen(msg),0,&addr,addrlen);
fprintf(stdout,"Server have received %s",msg); // 显示消息
}
}
int main(void)
{
int sockfd;
struct sockaddr_in addr;
/* 服务器端开始建立socket描述符 */
sockfd=socket(AF_INET,SOCK_DGRAM,0);
if(sockfd<0)
{
fprintf(stderr,"Socket Error:%s\n",strerror(errno));
exit(1);
}
/* 服务器端填充 sockaddr结构 */
bzero(&addr,sizeof(struct sockaddr_in));
addr.sin_family=AF_INET;
addr.sin_addr.s_addr=htonl(INADDR_ANY);
addr.sin_port=htons(SERVER_PORT);
/* 捆绑sockfd描述符 */
if(bind(sockfd,(struct sockaddr *)&addr,sizeof(struct sockaddr_in))<0)
{
fprintf(stderr,"Bind Error:%s\n",strerror(errno));
exit(1);
}
udps_respon(sockfd); // 进行读写操作
close(sockfd);
}
