network3w_echoc.c

/*
pineoc, 2015-03-16
week 3 network programming
iterative echo server & client
client code
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <arpa/inet.h>
#include <sys/socket.h>

#define BUF_SIZE 1024
void error_handling(char* msg);

int main(int argc,char* argv[])
{
	int sock;
	char msg[BUF_SIZE];
	int str_len;
	struct sockaddr_in serv_addr;

	if(argc!=3)
	{
		printf("Usage : %s <IP> <port> \n",argv[0]);
        exit(1);
	}

	sock = socket(PF_INET,SOCK_STREAM,0);
    if(sock==-1)
        error_handling("socket() err");
 
    memset(&serv_addr,0,sizeof(serv_addr));
    serv_addr.sin_family = AF_INET;
    serv_addr.sin_addr.s_addr = inet_addr(argv[1]);
    serv_addr.sin_port = htons(atoi(argv[2]));
 
    if(connect(sock,(struct sockaddr*)&serv_addr,sizeof(serv_addr))==-1)
        error_handling("connect() err");
    else
    	puts("connected.......");

    while(1)
    {
    	fputs("Input msg(Q to quit)",stdout);
    	fgets(msg,BUF_SIZE,stdin);

    	if((!strcmp(msg,"q\n")) || !strcmp(msg,"quit\n"))
    	{
    		break;
    	}

    	write(sock,msg,strlen(msg));
    	str_len = read(sock,msg,BUF_SIZE-1);
    	msg[str_len]=0;
    	printf("msg from server : %s",msg);
    }
    close(sock);

	return 0;
}

void error_handling(char* msg)
{
    fputs(msg,stderr);
    fputc('\n',stderr);
    exit(1);
}

network3w_echos.c

/*
pineoc, 2015-03-16
week 3 network programming
iterative echo server & client
server code
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <arpa/inet.h>
#include <sys/socket.h>

#define BUF_SIZE 1024
void error_handling(char* msg);

int main(int argc,char* argv[])
{
	int serv_sock,clnt_sock;
	char msg[BUF_SIZE];
	int str_len,i;

	struct sockaddr_in serv_addr,clnt_addr;
	socklen_t clnt_addr_sz;

	if(argc!=2)
	{
		printf("Usage :%s <port>\n",argv[0]);
		exit(1);
	}
	serv_sock = socket(PF_INET,SOCK_STREAM,0);
	if(serv_sock==-1)
        error_handling("socket() err");
    memset(&serv_addr,0,sizeof(serv_addr));
    serv_addr.sin_family=AF_INET;
    serv_addr.sin_addr.s_addr = htonl(INADDR_ANY);
    serv_addr.sin_port = htons(atoi(argv[1]));

    if(bind(serv_sock,(struct sockaddr*)&serv_addr,sizeof(serv_addr))==-1)
        error_handling("bind() err");

    if(listen(serv_sock,5)==-1)
        error_handling("listen() err");

    clnt_addr_sz = sizeof(clnt_addr);

    for(i=0;i<5;i++)
    {
    	clnt_sock=accept(serv_sock,(struct sockaddr*)&clnt_addr,&clnt_addr_sz);
    	if(clnt_sock==-1)
        	error_handling("accept() err");
        else
        	printf("connected client %d \n",i+1);
        while((str_len=read(clnt_sock,msg,BUF_SIZE))!=0)
        	write(clnt_sock,msg,str_len);

        close(clnt_sock);
    }
    close(serv_sock);

	return 0;
}

void error_handling(char* msg)
{
    fputs(msg,stderr);
    fputc('\n',stderr);
    exit(1);
}