#include 			<stdio.h> 			/* standard in/out procedures */
#include 			<stdlib.h>			/* defines system calls */
#include 			<string.h>			/* necessary for memset */
#include			<netdb.h>
#include 			<sys/socket.h>		/* used for all socket calls */
#include 			<netinet/in.h>		/* used for sockaddr_in */
#include			<arpa/inet.h>


#define SERV_PORT 	11111				/* define our server port number */
#define MSGLEN 		80  				/* limit incoming message size */

int
main(int argc, char** argv)
{
/* CREATE THE SOCKET */

	struct sockaddr_in servaddr; 		/* our server's address */
	struct sockaddr_in cliaddr;			/* the client's address */
	int sockfd; 						/* Initialize our socket */
	socklen_t addrlen = sizeof(cliaddr);/* length of address' */
	int recvlen;						/* number of bytes recieved */
	int msgnum = 0;						/* the messages we reveive in order */
	char buf[MSGLEN];			/* the incoming message */

/* create a UDP/IP socket */

	if((sockfd = socket(AF_INET, SOCK_DGRAM, 0)) < 0)
	{
		perror("cannot create socket");
		return 0;
	}
				
/*	printf("created socket descriptor = %d\n", sockfd);  */

/* INADDR_ANY = IP address and socket =  11111, modify SERV_PORT to change */
	memset((char *)&servaddr, 0, sizeof(servaddr));


	servaddr.sin_family 	 = AF_INET;
	/* host-to-network-long conversion (htonl) */
	servaddr.sin_addr.s_addr = htonl(INADDR_ANY);
	/* host-to-network-short conversion (htons) */
	servaddr.sin_port 		 = htons(SERV_PORT);


	if (bind(sockfd, (struct sockaddr *)&servaddr, sizeof(servaddr)) < 0) {
		perror("bind failed");
		return 0;
	}

/* loop, listen for client, print received, reply to client */
	for(;;) {
		printf("waiting for client message on port %d\n", SERV_PORT);
		recvlen = recvfrom(sockfd, buf, MSGLEN, 0, (struct sockaddr *)&cliaddr, &addrlen);
		printf("heard %d bytes\n", recvlen);
		if (recvlen > 0) {
			buf[recvlen] = 0;
			printf("I heard this: \"%s\"\n", buf);
	}
	else
		printf("lost the connection to client\n");
	sprintf(buf, "Message #%d received\n", msgnum++);
	printf("reply sent \"%s\"\n", buf);
	if (sendto(sockfd, buf, strlen(buf), 0, (struct sockaddr *)&cliaddr, addrlen) < 0)
		perror("sendto");
	/* continues to loop, use "Ctrl+C" to terminate listening */

	}
}