network4w_uecho_client_connected.c

/*
pineoc, 2015-03-23
week 4 network programming
udp echo server & client + connected
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 32

#define CONNECTEDMODE 1

void error_handling(char* msg);

int main(int argc,char* argv[])
{
	int sock;
	char msg[BUF_SIZE];
	int str_len;
	socklen_t addr_sz;

	struct sockaddr_in serv_addr,from_addr;

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

	sock = socket(PF_INET,SOCK_DGRAM,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(CONNECTEDMODE==1)
    if(connect(sock,(struct sockaddr*)&serv_addr,sizeof(serv_addr))==-1)
        error_handling("connect() err");
#endif

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

    	if((!strcmp(msg,"q\n")) || !strcmp(msg,"Q\n"))
    		break;
#if(CONNECTEDMODE==0)
    	sendto(sock,msg,strlen(msg),0,(struct sockaddr*)&serv_addr,sizeof(serv_addr));
    	addr_sz=sizeof(from_addr);
    	str_len = recvfrom(sock,msg,BUF_SIZE,0,(struct sockaddr*)&from_addr,addr_sz);
#else
        write(sock,msg,strlen(msg));
        str_len = read(sock,msg,sizeof(msg)-1);
#endif
        msg[str_len]=0;
        printf("Message from server : %s",msg);
    }

    close(sock);
	return 0;
}

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