#define _XOPEN_SOURCE   500
#define __EXTENSIONS__

/*
 * Simple networking server which uses SCTP 1-N 
 */
#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 <netinet/sctp.h>


#define MAXIDLETIME     1


static void
print_src(int fd, sctp_assoc_t assoc_id)
{
	struct sctp_status sstat;
	struct sctp_paddrinfo *spinfo;
	char tmpname[INET_ADDRSTRLEN];
	unsigned int port;
	unsigned int ulen;
	struct sockaddr_in *s_in;

	bzero(&sstat, sizeof (sstat));

	ulen = sizeof (sstat);
	if (sctp_opt_info(fd, assoc_id, SCTP_STATUS, &sstat, &ulen) < 0) {
		perror("sctp_opt_info()");
		return;
	}
	spinfo = &sstat.sstat_primary;

	s_in = (struct sockaddr_in *)&spinfo->spinfo_address;
	inet_ntop(AF_INET, &s_in->sin_addr, tmpname, sizeof (tmpname));
	port = ntohs(s_in->sin_port);
	printf("Msg from %d: %s/%d\n", assoc_id, tmpname, port);
}

int
main(int argc, char **argv)
{
	int echo_s;
	struct sockaddr_in laddr;
	struct sctp_event_subscribe ses;
	int ret;
	struct msghdr mhdr;
	struct iovec iov;
	char data[8192];
	char cdata[sizeof (struct sctp_sndrcvinfo) + sizeof (struct cmsghdr)];
	struct cmsghdr *cmsg;
	struct sctp_sndrcvinfo *sinfo;
	struct sctp_assoc_change *sac;
	struct sockaddr_in from;
	socklen_t fromlen = sizeof (struct sockaddr_in);
	fd_set	rset;
	int i;

        if (argc < 2) {
		 printf("usage: sctp_server <local_port>\n");
                 exit(0);
        }

	echo_s = socket(AF_INET, SOCK_SEQPACKET, IPPROTO_SCTP);

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

	i = 1;
	setsockopt(echo_s, SOL_SOCKET, SO_REUSEADDR, &i, sizeof (i));
	i = MAXIDLETIME;
	setsockopt(echo_s, IPPROTO_SCTP, SCTP_AUTOCLOSE, &i, sizeof (i));

	bzero(&ses, sizeof (ses));
	ses.sctp_data_io_event = 1;
	setsockopt(echo_s, IPPROTO_SCTP, SCTP_EVENTS, &ses, sizeof (ses));

	FD_ZERO(&rset);

	while (1) {
		FD_SET(echo_s, &rset);
		select(5, &rset, NULL, NULL, NULL);
		if (FD_ISSET(echo_s, &rset) ) {
			bzero(cdata, sizeof (cdata));
			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;
			sinfo = (struct sctp_sndrcvinfo *)(cmsg + 1);

			if ((ret = recvmsg(echo_s, &mhdr, MSG_DONTWAIT)) < 0) {
				perror("recvmsg()");
			}
			if (mhdr.msg_controllen) {
				print_src(echo_s, sinfo->sinfo_assoc_id);
			}
			/* echo back */
			iov.iov_len = ret;
			if (sendmsg(echo_s, &mhdr, MSG_DONTWAIT) < 0) {
				perror("sendmsg()");
			}
			printf("received:");
			fflush(stdout);
			write(1, data, ret);
		}
	}
}