C/S

client.c

#include<errno.h>
#include<semaphore.h>
#include<string.h>
#include<sys/stat.h>
#include<fcntl.h>
#include<errno.h>
#include<stdlib.h>
#include<unistd.h>
#include<stdio.h>
#include<sys/mman.h>
<pre class="cpp" name="code">#include<errno.h>
#include<semaphore.h>
#include<string.h>
#include<sys/stat.h>
#include<fcntl.h>
#include<errno.h>
#include<stdlib.h>
#include<unistd.h>
#include<stdio.h>
#include<sys/mman.h>
#include<sys/types.h>
#include<signal.h>
#include<pthread.h>
#include<netinet/in.h>
#include<arpa/inet.h>
#include<sys/socket.h>
#define SERVER_PORT 8000
#define MAXLINE 4096
int main(){
	struct sockaddr_in serveraddr,clientaddr;
	int sockfd,addrlen,confd,len,i;
	char ipstr[128];
	char buf[MAXLINE];

	sockfd=socket(AF_INET,SOCK_STREAM,0);
	bzero(&serveraddr,sizeof(serveraddr));
	serveraddr.sin_family=AF_INET;
	serveraddr.sin_addr.s_addr=htonl(INADDR_ANY);
	serveraddr.sin_port=htons(SERVER_PORT);
	bind(sockfd,(struct sockaddr*)&serveraddr,sizeof(serveraddr));
	listen(sockfd,128);
	while(1){
		addrlen=sizeof(clientaddr);
		confd=accept(sockfd,(struct sockaddr*)&clientaddr,&addrlen);
		inet_ntop(AF_INET,&clientaddr.sin_addr.s_addr,ipstr,sizeof(ipstr));
		printf("client ip %s\nport %d\n",ipstr,ntohs(clientaddr.sin_port));
		len=read(confd,buf,sizeof(buf));
		i=0;
		while(i<len){
			buf[i]=toupper(buf[i]);
			i++;
		}
		write(STDOUT_FILENO,buf,len);
		write(confd,buf,len);
		close(confd);
	}
	close(sockfd);
	return 0;
}

server.c

#include<errno.h>
#include<semaphore.h>
#include<string.h>
#include<sys/stat.h>
#include<fcntl.h>
#include<errno.h>
#include<stdlib.h>
#include<unistd.h>
#include<stdio.h>
#include<sys/mman.h>
#include<sys/types.h>
#include<signal.h>
#include<pthread.h>
#include<netinet/in.h>
#include<arpa/inet.h>
#include<sys/socket.h>
#define SERVER_PORT 8000
#define MAXLINE 4096
int main(){
	struct sockaddr_in serveraddr,clientaddr;
	int sockfd,addrlen,confd,len,i;
	char ipstr[128];
	char buf[MAXLINE];

	sockfd=socket(AF_INET,SOCK_STREAM,0);
	bzero(&serveraddr,sizeof(serveraddr));
	serveraddr.sin_family=AF_INET;
	serveraddr.sin_addr.s_addr=htonl(INADDR_ANY);
	serveraddr.sin_port=htons(SERVER_PORT);
	bind(sockfd,(struct sockaddr*)&serveraddr,sizeof(serveraddr));
	listen(sockfd,128);
	while(1){
		addrlen=sizeof(clientaddr);
		confd=accept(sockfd,(struct sockaddr*)&clientaddr,&addrlen);
		inet_ntop(AF_INET,&clientaddr.sin_addr.s_addr,ipstr,sizeof(ipstr));
		printf("client ip %s\nport %d\n",ipstr,ntohs(clientaddr.sin_port));
		len=read(confd,buf,sizeof(buf));
		i=0;
		while(i<len){
			buf[i]=toupper(buf[i]);
			i++;
		}
		write(STDOUT_FILENO,buf,len);
		write(confd,buf,len);
		close(confd);
	}
	close(sockfd);
	return 0;
}