#define _XOPEN_SOURCE   500
#define __EXTENSIONS__

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <sys/signal.h>
#include <sys/socket.h>
#include <sys/filio.h>

#include "mcast.h"
#define SA      struct sockaddr

void            init_mhdr();
void            display_addr();


struct msghdr   mhdr;
struct iovec    iov;
char            data[8192];
char            cdata[sizeof(struct sockaddr_in) + sizeof(struct cmsghdr)];
struct cmsghdr *cmsg;
struct sockaddr_in from;
socklen_t       fromlen = sizeof(struct sockaddr_in);
struct in_addr  ip_addr;
struct cmsghdr *cmptr;
char            str[32];

int
main(int argc, char **argv)
{

	int             echo_s;
	struct sockaddr_in laddr;
	int             ret;
	int             loop;

	if (argc < 2) {
		printf("usage: %s <group IP> <local_port>\n", argv[0]);
		exit(0);
	}
	echo_s = socket(AF_INET, SOCK_DGRAM, 0);
	reusePort(echo_s);

	bzero(&laddr, sizeof(laddr));
	laddr.sin_family = AF_INET;
	laddr.sin_port = htons(atoi(argv[2]));
	if (bind(echo_s, (struct sockaddr *) & laddr, sizeof(laddr)) < 0) {
		perror("bind error");
		exit(1);
	}
	displayDaddr(echo_s);

	joinGroup(echo_s, argv[1]);
	joinGroup(echo_s, "224.0.0.2");
	joinGroup(echo_s, "224.0.0.3");

	loop = 1;
	setLoopback(echo_s, loop);


	while (1) {

/*  using recvmsg &  sendmsg */
printf("\n.... Using recvMSG & sendMSG ....\n");
		init_mhdr();
		if ((ret = recvmsg(echo_s, &mhdr, MSG_WAITALL)) < 0) {
			perror("recvmsg()");
		}
		printf("received:");
		fflush(stdout);
		write(1, data, ret);
		display_addr();

		iov.iov_len = ret;
		if (sendmsg(echo_s, &mhdr, MSG_DONTWAIT) < 0) {
			perror("sendmsg()");
			exit(-1);
		}
/*  using recvfrom & sendto */
/*
printf("\n.... Using recvFROM & sendTO ....\n");
		if ((ret = recvfrom(echo_s, data, sizeof(data), 0, 
			(SA *) & from, &fromlen)) < 0) {
			perror("recvfrom");
		}
		printf("received:");
		fflush(stdout);
		write(1, data, ret);
		printf("udp message sent  from: %s:%d\n", 
                        inet_ntop(AF_INET, &from.sin_addr, str, sizeof(str)), 
			ntohs(from.sin_port));

		if (sendto(echo_s, data, ret, 0, (SA *) & from, fromlen) < 0) {
			printf("error in sendto\n");
			exit(-1);
		}
*/
	}
}
void
init_mhdr()
{
	bzero(cdata, sizeof(cdata));
	bzero(data, sizeof(data));
	bzero(&mhdr, sizeof(mhdr));
	mhdr.msg_name = &from;
	mhdr.msg_namelen = fromlen;
	mhdr.msg_iov = &iov;
	mhdr.msg_iovlen = 1;
	mhdr.msg_control = cdata;
	mhdr.msg_controllen = sizeof(cdata);
	iov.iov_base = data;
	iov.iov_len = sizeof(data);
	cmsg = (struct cmsghdr *) cdata;
}

void
display_addr()
{

	for (cmptr = CMSG_FIRSTHDR(&mhdr); cmptr != NULL;
	     cmptr = CMSG_NXTHDR(&mhdr, cmptr)) {
		if (cmptr->cmsg_level == IPPROTO_IP &&
		    cmptr->cmsg_type == IP_RECVDSTADDR) {
			memcpy(&ip_addr, CMSG_DATA(cmptr), sizeof(struct in_addr));
			printf("udp message sent  to: %s\n", 
			inet_ntop(AF_INET, &ip_addr, str, sizeof(str)));
			printf("udp message sent  from: %s:%d\n", 
			inet_ntop(AF_INET, &from.sin_addr, str,
					sizeof(str)), ntohs(from.sin_port));
		}
	}
}