/*-
 * Copyright (c) 1993-1994 The Regents of the University of California.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by the Network Research
 *	Group at Lawrence Berkeley Laboratory.
 * 4. Neither the name of the University nor of the Laboratory may be used
 *    to endorse or promote products derived from this software without
 *    specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */
static const char rcsid[] =
    "@(#) $Header: /cs/research/mice/starship/src/local/CVS_repository/vic/transmitter.cc,v 1.2 1999/03/17 15:34:34 piers Exp $ (LBL)";

#include <stdio.h>
#include <stdlib.h>
#ifndef WIN32
#include <unistd.h>
#endif
#include <errno.h>
#include <string.h>
#ifdef WIN32
//#include <winsock.h>
#include <io.h>
#include <sys/stat.h>
#else
#include <sys/param.h>
#include <sys/uio.h>
#include <netinet/in.h>
#include <sys/file.h>
#include <sys/stat.h>
#endif
#include "ntp-time.h"
#include "transmitter.h"
#include "net.h"
#include "source.h"
#include "decoder.h"
#include "Tcl.h"

#if defined(sun) && !defined(__svr4__) || (defined(_AIX) && !defined(_AIX41))
extern "C" writev(int, iovec*, int);
#endif

Transmitter::pktbuf* Transmitter::freehdrs_;
Transmitter::buffer* Transmitter::freebufs_;
int Transmitter::nbufs_;
int Transmitter::nhdrs_;

/*
 * Sequence number is static so when we change the encoding (which causes
 * new encoder to be allocated) we don't reset the sequence counter.
 * Otherwise, receivers will get confused, reset their stats, and generate
 * odd looking streams of reception reports (i.e., the packet counts will
 * drop back to 0).
 */
u_int16_t Transmitter::seqno_ = 1;

Transmitter::Transmitter() :
	mtu_(1024),
	nf_(0),
	nb_(0),
	np_(0),
	kbps_(128),
	nextpkttime_(0.),
	busy_(0),
	head_(0),
	tail_(0),
	loopback_(1)
{
	memset((char*)&mh_, 0, sizeof(mh_));
	mh_.msg_iovlen = 2;
}

inline double Transmitter::gettimeofday() const
{
	timeval tv;
	::gettimeofday(&tv, 0);
	return (tv.tv_sec + 1e-6 * tv.tv_usec);
}

Transmitter::pktbuf* Transmitter::alloch(u_int32_t ts, int fmt)
{
	pktbuf* pb = freehdrs_;
	if (pb != 0)
		freehdrs_ = pb->next;
	else {
		/*XXX grow exponentially*/
		pb = new pktbuf;
		++nhdrs_;
	}
	rtphdr* rh = (rtphdr*)pb->hdr;
	int flags = RTP_VERSION << 14 | fmt;
	rh->rh_flags = ntohs(flags);
	rh->rh_seqno = htons(seqno_);
	++seqno_;
	rh->rh_ts = htonl(ts);
	rh->rh_ssrc = SourceManager::instance().localsrc()->srcid();

	pb->iov[0].iov_base = (char*)rh;
	pb->buf = 0;

	return (pb);
}

Transmitter::pktbuf* Transmitter::alloc(u_int32_t ts, int fmt)
{
	pktbuf* pb = alloch(ts, fmt);
	buffer* p = freebufs_;
	if (p != 0)
		freebufs_ = p->next;
	else
		p = new buffer;

	pb->buf = p;
	pb->iov[1].iov_base = (char*)p->data;
	return (pb);
}

void Transmitter::loopback(pktbuf* pb)
{
	rtphdr* rh = (rtphdr*)pb->hdr;
	int cc = pb->iov[0].iov_len + pb->iov[1].iov_len;
	/*
	 * Update statistics.
	 */
	nb_ += cc;
	++np_;

	SourceManager& sm = SourceManager::instance();
	Source& s = *sm.localsrc();
	timeval now = unixtime();
	s.lts_data(now);
	s.action();
	s.sts_data(rh->rh_ts);
	s.np(1);
	s.nb(cc);
	s.cs((u_int16_t)ntohs(rh->rh_seqno));

	int flags = ntohs(rh->rh_flags);
	if (flags & RTP_M) {
		++nf_;
		s.nf(1);
	}
	int fmt = flags & 0x7f;
	/*
	 * Handle initialization of loopback decoder
	 * and changes in the stream.
	 */
	PacketHandler* h = s.handler();
	if (h == 0)
		h = s.activate(fmt);
	else if (s.format() != fmt)
		h = s.change_format(fmt);

	if (s.mute() || !loopback_)
		return;

	h->recv(rh, (u_char*)pb->iov[1].iov_base, pb->iov[1].iov_len);
}

int Transmitter::dumpfd_ = -1;
void Transmitter::dump(int fd)
{
	dumpfd_ = fd;
#define MAGIC "RTPCLIP 1.0"
	(void)write(fd, MAGIC, sizeof(MAGIC));
}

/*XXX*/
#ifdef WIN32
int writev(int fd, iovec* iov, int iovlen)
{
	int len = 0, n;
	for (int i = 0; i < iovlen; i++) {
		if ((n = write(fd, iov[i].iov_base, iov[i].iov_len)) == -1) {
			perror("writev");
			exit(1);
		}
		len += n;
	}
	return(len);
}
#endif

void Transmitter::dump(int fd, iovec* iov, int iovlen) const
{
	register int length = 0;
	for (int i = iovlen; --i >= 0; )
		length += iov[i].iov_len;

	char cliphdr[4];
	*(short*)cliphdr = htons(length);
	cliphdr[2] = 0; /* data packet (i.e., not an rtcp packet) */
	cliphdr[3] = 0; /* ? */

	(void)write(fd, cliphdr, 4);
	if (writev(fd, iov, iovlen) < 0) {
		perror("write");
		exit(1);
	}
}

/*
 * Time it takes in seconds to send this
 * packet at the configured bandwidth.
 */
double Transmitter::txtime(pktbuf* pb)
{
	int cc = pb->iov[0].iov_len + pb->iov[1].iov_len;
	return (8 * cc / (1000. * kbps_));
}

void Transmitter::send(pktbuf* pb)
{
	if (!busy_) {
		double delay = txtime(pb);
		nextpkttime_ = gettimeofday() + delay;
		output(pb);
		/*
		 * emulate a transmit interrupt --
		 * assume we will have more to send.
		 */
		msched(int(delay * 1e-3));
		busy_ = 1;
	} else {
		if (head_ != 0) {
			tail_->next = pb;
			tail_ = pb;
		} else
			tail_ = head_ = pb;
		pb->next = 0;
	}
}

void Transmitter::timeout()
{
	double now = gettimeofday();
	for (;;) {
		pktbuf* p = head_;
		if (p != 0) {
			head_ = p->next;
			nextpkttime_ += txtime(p);
			output(p);
			int ms = int(1e-3 * (nextpkttime_ - now));
			/* make sure we will wait more than 10ms */
			if (ms > 1000) {
				msched(ms);
				return;
			}
		} else {
			busy_ = 0;
			break;
		}
	}
}

void Transmitter::flush()
{
	if (busy_) {
		busy_ = 0;
		cancel();
	}

	pktbuf* p = head_;
	while (p != 0) {
		pktbuf* n = p->next;
		output(p);
		p = n;
	}
	head_ = 0;
}

void Transmitter::output(pktbuf* pb)
{
	if (dumpfd_ >= 0)
		dump(dumpfd_, pb->iov, mh_.msg_iovlen);
	transmit(pb);
	loopback(pb);
	release(pb);
}

void Transmitter::release(pktbuf* pb)
{
	pb->next = freehdrs_;
	freehdrs_ = pb;
	buffer* p = pb->buf;
	if (p != 0) {
		p->next = freebufs_;
		freebufs_ = p;
	}
}