rtpparse.c

ortp协议栈（实时传输协议）

/*
  The oRTP library implements the RTP protocol (rfc1889).
  Copyright (C) 2001  Simon MORLAT [e-mail]

  This library is free software; you can redistribute it and/or
  modify it under the terms of the GNU Lesser General Public
  License as published by the Free Software Foundation; either
  version 2.1 of the License, or (at your option) any later version.

  This library is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  Lesser General Public License for more details.

  You should have received a copy of the GNU Lesser General Public
  License along with this library; if not, write to the Free Software
  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
*/



#include "ortp.h"


void rtp_parse(RtpSession *session,mblk_t *mp)
{
	gint i,header_size;
	mblk_t *mdata;
	rtp_header_t *rtp;
	gint msgsize;
	
	g_return_if_fail(mp!=NULL);
#ifdef TARGET_IS_HPUXKERNEL
	if (mp->b_cont!=NULL){
		mblk_t *newm;
		/* the message is fragmented, we need to reassemble it*/
		newm=msgpullup(mp,-1);
		freemsg(mp);
		mp=newm;
	}
#endif
	
	msgsize=msgdsize(mp);
	ortp_global_stats.hw_recv+=msgsize;
	session->stats.hw_recv+=msgsize;
	ortp_global_stats.packet_recv++;
	session->stats.packet_recv++;
	
	rtp=(rtp_header_t*)mp->b_rptr;
	if (rtp->version!=2)
	{
		g_message("Receiving rtp packet with version number !=2...discarded");
		session->stats.bad++;
		ortp_global_stats.bad++;
		freemsg(mp);
		return;
	}
	
	/* convert all header data from network order to host order */
	rtp->seq_number=ntohs(rtp->seq_number);
	rtp->timestamp=ntohl(rtp->timestamp);
	rtp->ssrc=ntohl(rtp->ssrc);
	/* convert csrc if necessary */
	for (i=0;i<rtp->cc;i++)
		rtp->csrc[i]=ntohl(rtp->csrc[i]);
	if (session->ssrc!=0)
	{
		/*the ssrc is set, so we must check it */
		if (session->ssrc!=rtp->ssrc){
			//g_message("rtp_parse: bad ssrc - %i",rtp->ssrc);
			session->ssrc=rtp->ssrc;
			rtp_signal_table_emit(&session->on_ssrc_changed);
		}
	}else session->ssrc=rtp->ssrc;
	
	if (!(session->flags & RTP_SESSION_RECV_SYNC)){
		
		/* avoid very old packet to enqueued, because the user is no more supposed to get them */
		if (RTP_TIMESTAMP_IS_NEWER_THAN(session->rtp.rcv_last_ts,rtp->timestamp)){
			g_message("rtp_parse: silently discarding very old packet (ts=%i)",rtp->timestamp);
			freemsg(mp);
			session->stats.outoftime+=msgsize;
			ortp_global_stats.outoftime+=msgsize;
			return;
		}
	}
	/* creates a new mblk_t to be linked with the rtp header*/
	mdata=dupb(mp);
	header_size=RTP_FIXED_HEADER_SIZE+ (4*rtp->cc);
	mp->b_wptr=mp->b_rptr+header_size;
	mdata->b_rptr+=header_size;
	/* link proto with data */
	mp->b_cont=mdata;
	/* and then add the packet to the queue */
	
	rtp_putq(session->rtp.rq,mp);
	/* make some checks: q size must not exceed RtpStream::max_rq_size */
	while (session->rtp.rq->q_count> session->rtp.max_rq_size)
	{
		/* remove the oldest mblk_t */
		mp=getq(session->rtp.rq);
		if (mp!=NULL)
		{
			msgsize=msgdsize(mp);
			g_message("rtp_putq: Queue is full. Discarding message with ts=%i",((rtp_header_t*)mp->b_rptr)->timestamp);
			freemsg(mp);
			session->stats.discarded+=msgsize;
			ortp_global_stats.discarded+=msgsize;
		}
	}
}