server.c

用户数据报协议的程序源码

#include <sys/types.h>
#include <sys/socket.h>
#include <string.h>
#include <netinet/in.h>
#include <stdio.h>
#include <stdlib.h>
 
#define MAXLINE         80
#define SERV_PORT       8888
 
void do_echo(int sockfd, struct sockaddr *pcliaddr, socklen_t clilen)
{
        int n;
        socklen_t len;
        char mesg[MAXLINE];
 
        for(;;)
        {
                len = clilen;
		memset(mesg,0,MAXLINE);
                /* waiting for receive data */
                n = recvfrom(sockfd, mesg, MAXLINE, 0, pcliaddr, &len);
		printf("%s \n",mesg);
		//printf("addr=%d \n",(struct sockaddr_in *)(pcliaddr)->sin_addr);

                /* sent data back to client */
                sendto(sockfd, mesg, n, 0, pcliaddr, len);
        }
}
 
int main(void)
{
        int sockfd;
        struct sockaddr_in servaddr, cliaddr;

        sockfd = socket(AF_INET, SOCK_DGRAM, 0); /* create a socket */
 
        /* init servaddr */
        bzero(&servaddr, sizeof(servaddr));
        servaddr.sin_family = AF_INET;
        servaddr.sin_addr.s_addr = htonl(INADDR_ANY);
        servaddr.sin_port = htons(SERV_PORT);
 
        /* bind address and port to socket */
        if(bind(sockfd, (struct sockaddr *)&servaddr, sizeof(servaddr)) == -1)
        {
                perror("bind error");
                exit(1);
        }
 
        do_echo(sockfd, (struct sockaddr *)&cliaddr, sizeof(cliaddr));

        return 0;
}