服务器端：
#include<stdio.h>
#include<stdlib.h>
#include<sys/socket.h>
#include<arpa/inet.h>
#include<string.h>
#include<errno.h>
#include<unistd.h>
#define BUFSIZE 1024
int main(void)
{
struct sockaddr_in local_addr,remote_addr;
int sockfd;
int server_ip,nrecv;
int alen;
FILE *fp;
char buffer[BUFSIZE];
memset(&local_addr,0,sizeof(local_addr));
local_addr.sin_family=AF_INET;
local_addr.sin_port=htons(5666);
inet_pton(AF_INET,"127.0.0.1",(void*)&server_ip);
local_addr.sin_addr.s_addr=server_ip;
sockfd=socket(AF_INET,SOCK_DGRAM,0);
if(bind(sockfd,(struct sockaddr*)&local_addr,sizeof(struct sockaddr))<0){
fprintf(stderr,"error:bind() error!\n");
exit(-1);
}
printf("====================Begin to service====================\n");
while(1){
if((nrecv=recvfrom(sockfd,buffer,BUFSIZE,0,(struct sockaddr*)&remote_addr,&alen))<0){
fprintf(stderr,"error:%s\n",strerror(errno));
exit(1);
}else
{
buffer[nrecv]='\0';
sendto(sockfd,buffer,strlen(buffer),0,(struct sockaddr*)&remote_addr,alen);
}
}
exit(0);
}
客户端：
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <strings.h>
#include <string.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h>
#define PORT 1234
#define MAXDATASIZE 100
int main(int argc, char *argv[])
{
int fd, numbytes;
int server_ip;
char recvbuf[MAXDATASIZE];
char sendbuf[MAXDATASIZE];
struct hostent *he;
struct sockaddr_in server,client;
if ((fd=socket(AF_INET, SOCK_DGRAM, 0))==-1){
printf("socket() error\n");
exit(1);
}
bzero(&server,sizeof(server));
server.sin_family=AF_INET;
server.sin_port=htons(5666);
inet_pton(AF_INET,"127.0.0.1",(void*)&server_ip);
server.sin_addr.s_addr=server_ip;
socklen_t len;
len=sizeof(struct sockaddr_in);
while (1) {
printf("input message:");
fgets(sendbuf,40,stdin);
sendto(fd,sendbuf,strlen(sendbuf),0,(struct sockaddr *)&server,len);
if ((numbytes=recvfrom(fd,recvbuf,MAXDATASIZE,0,(struct sockaddr *)&server,&len)) == -1){
printf("recvfrom() error\n");
exit(1);
}
recvbuf[numbytes]='\0';
printf("Server Return Reverse Message: %s\n",recvbuf);
}
close(fd);
}
完毕
