c udp client and server

/*
	Simple udp client
	Silver Moon (m00n.silv3r@gmail.com)
*/
#include<stdio.h>	//printf
#include<string.h> //memset
#include<stdlib.h> //exit(0);
#include<arpa/inet.h>
#include<sys/socket.h>

#define SERVER "127.0.0.1"
#define BUFLEN 512	//Max length of buffer
#define PORT 8888	//The port on which to send data

void die(char *s)
{
	perror(s);
	exit(1);
}

int main(void)
{
	struct sockaddr_in si_other;
	int s, i, slen=sizeof(si_other);
	char buf[BUFLEN];
	char message[BUFLEN];

	if ( (s=socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP)) == -1)
	{
		die("socket");
	}

	memset((char *) &si_other, 0, sizeof(si_other));
	si_other.sin_family = AF_INET;
	si_other.sin_port = htons(PORT);
	
	if (inet_aton(SERVER , &si_other.sin_addr) == 0) 
	{
		fprintf(stderr, "inet_aton() failed\n");
		exit(1);
	}

	while(1)
	{
		printf("Enter message : ");
		gets(message);
		
		//send the message
		if (sendto(s, message, strlen(message) , 0 , (struct sockaddr *) &si_other, slen)==-1)
		{
			die("sendto()");
		}
		
		//receive a reply and print it
		//clear the buffer by filling null, it might have previously received data
		memset(buf,'\0', BUFLEN);
		//try to receive some data, this is a blocking call
		if (recvfrom(s, buf, BUFLEN, 0, (struct sockaddr *) &si_other, &slen) == -1)
		{
			die("recvfrom()");
		}
		
		puts(buf);
	}

	close(s);
	return 0;
}




/*
	Simple udp server
	Silver Moon (m00n.silv3r@gmail.com)
*/
#include<stdio.h>	//printf
#include<string.h> //memset
#include<stdlib.h> //exit(0);
#include<arpa/inet.h>
#include<sys/socket.h>

#define BUFLEN 512	//Max length of buffer
#define PORT 8888	//The port on which to listen for incoming data

void die(char *s)
{
	perror(s);
	exit(1);
}

int main(void)
{
	struct sockaddr_in si_me, si_other;
	
	int s, i, slen = sizeof(si_other) , recv_len;
	char buf[BUFLEN];
	
	//create a UDP socket
	if ((s=socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP)) == -1)
	{
		die("socket");
	}
	
	// zero out the structure
	memset((char *) &si_me, 0, sizeof(si_me));
	
	si_me.sin_family = AF_INET;
	si_me.sin_port = htons(PORT);
	si_me.sin_addr.s_addr = htonl(INADDR_ANY);
	
	//bind socket to port
	if( bind(s , (struct sockaddr*)&si_me, sizeof(si_me) ) == -1)
	{
		die("bind");
	}
	
	//keep listening for data
	while(1)
	{
		printf("Waiting for data...");
		fflush(stdout);
		
		//try to receive some data, this is a blocking call
		if ((recv_len = recvfrom(s, buf, BUFLEN, 0, (struct sockaddr *) &si_other, &slen)) == -1)
		{
			die("recvfrom()");
		}
		
		//print details of the client/peer and the data received
		printf("Received packet from %s:%d\n", inet_ntoa(si_other.sin_addr), ntohs(si_other.sin_port));
		printf("Data: %s\n" , buf);
		
		//now reply the client with the same data
		if (sendto(s, buf, recv_len, 0, (struct sockaddr*) &si_other, slen) == -1)
		{
			die("sendto()");
		}
	}

	close(s);
	return 0;
}

//http://www.binarytides.com/programming-udp-sockets-c-linux/