void send_file(int sk)
{
    struct msghdr outmsg;
    char outcmsg[CMSG_SPACE(sizeof(struct sctp_sndrcvinfo))];
    struct cmsghdr *cmsg;
    struct sctp_sndrcvinfo *sinfo;
    struct iovec iov;
    char message[1500];
    struct hostent *hst;
    struct sockaddr *addrs;
    int msglen;
    int error = 0;
    int try_error=0;
    int stream = 1;
    //Kiem lai dia chi dich va gan cac thong tin phu hop
        if (remote_host != NULL) {
		hst = gethostbyname(remote_host);
		if (hst == NULL || hst->h_length < 1) {
			fprintf(stderr, "%s: bad hostname: \n",
				remote_host);
			exit(1);
		}
		ra_family = hst->h_addrtype;
                ra_len = sizeof(remote_addr);
                ra_raw = &remote_addr.sin_addr;
		remote_addr.sin_port = htons(8000);
		remote_addr.sin_family = AF_INET;
		memcpy(ra_raw, hst->h_addr_list[0], hst->h_length);
        }
        else
        {
            //Hostname khong ton tai thoat chuong trinh...
            printf("Not found remote host!!!\n");
            printf("Shutdown program.\n");
            exit(1);
        }
        printf("Host name is %s.\n",remote_host);
        // KIem tra su ton tai cua ket noi toi remote addrs
        if ((SOCK_SEQPACKET == socket_type) && associd &&
            (0 != test_sk_for_assoc(sk, associd))) {
		associd = test_recv_assoc_change(sk);
		printf("Old association gone, Starting a new one!\n");
		new_connection = 1;
	}
        int fd;
        if ( localfile == NULL ) fd = 0;
	fd = open(localfile,O_RDONLY);
        if(fd==-1)
        {
            printf("Read file error.\n");
            exit(1);
        }
	fprintf(stderr," ready to send...\n");
        printf("Ready to send file....\n");
        msglen=read(fd,message,1024);
        do {
            /* Initialize the message struct we use to pass
		 * messages to the remote socket.
             */
            try_error++;
            if(try_error==100)
            {
                printf("Can't connect remote address,program shutdown.\n");
                exit(1);
            }
            iov.iov_base = message;
            iov.iov_len = msglen;
            outmsg.msg_iov = &iov;
            outmsg.msg_iovlen = 1;
            outmsg.msg_control = outcmsg;;
            outmsg.msg_controllen = sizeof(outcmsg);
            outmsg.msg_name = &remote_addr;
            outmsg.msg_namelen = ra_len;
            cmsg = CMSG_FIRSTHDR(&outmsg);
            cmsg->cmsg_level = IPPROTO_SCTP;
            cmsg->cmsg_type = SCTP_SNDRCV;
            cmsg->cmsg_len = CMSG_LEN(sizeof(struct sctp_sndrcvinfo));
            outmsg.msg_controllen = cmsg->cmsg_len;
            sinfo = (struct sctp_sndrcvinfo *)CMSG_DATA(cmsg);
            memset(sinfo, 0, sizeof(struct sctp_sndrcvinfo));
            sinfo->sinfo_flags = 0;
            sinfo->sinfo_stream = 1;
            sinfo->sinfo_ppid=rand();
            error = sendmsg(sk, &outmsg, MSG_WAITALL);
            if (error != msglen) 
		printf(stderr, ": error: %s.\n", strerror(errno));
	} while (error != msglen);

    /* If this is the first message sent over a UDP-style socket,
     * get the associd from the SCTP_ASSOC_CHANGE notification.
     */
	if ((SOCK_SEQPACKET == socket_type) && (0 == associd))
			associd = test_recv_assoc_change(sk);

	/* Verify there is no association.  */
	if (0 != test_sk_for_assoc(sk, associd)) {
		printf("No association is present now!!\n");
		new_connection = 1;
		}
        else {
		if (new_connection) {
		int rc = sctp_getpaddrs(sk, associd, &addrs);
		if (0 >= rc) {
                    if (rc == 0) {
			fprintf(stderr, "sctp_getpaddrs failed, no peers.\n");
                    } else {
			fprintf(stderr, "sctp_getpaddrs failed %s(%d).\n", strerror(errno), errno);
			}
                         exit(1);
		}
		printf("New connection, peer addresses\n");
		//print_addr_buf(addrs, rc);
		sctp_freepaddrs(addrs);
		new_connection = 0;
		}
        }
        iov.iov_base = buffer;
	iov.iov_len = 1;
	outmsg.msg_iov = &iov;
	outmsg.msg_iovlen = 1;
        /* open the file */
	
	while ( (msglen = read(fd,buffer,1024)) > 0 ) {
		/* Send to our neighbor.  */
            if(stream==1) stream=2;
            if(stream==2)  stream=1;
            sinfo->sinfo_stream = stream;
			iov.iov_len = msglen;
		 sendmsg(sk, &outmsg, MSG_WAITALL);
	}

	close(fd);
	close(sk);
}