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/*
The oRTP library is an RTP (Realtime Transport Protocol - rfc1889) stack.
Copyright (C) 2001 Simon MORLAT simon.morlat@linphone.org
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 <rtp.h>
#include "rtpmod.h"
#define RTP_SEQ_IS_GREATER(seq1,seq2)\
((guint16)((guint16)(seq1) - (guint16)(seq2))< (guint16)(1<<15))
/* put an rtp packet in queue. It is called by rtp_parse()*/
void rtp_putq(queue_t *q, mblk_t *mp)
{
mblk_t *tmp;
rtp_header_t *rtp=(rtp_header_t*)mp->b_rptr,*tmprtp;
/* insert message block by increasing time stamp order : the last (at the bottom)
message of the queue is the newest*/
ortp_debug("rtp_putq(): Enqueuing packet with ts=%i and seq=%i",rtp->timestamp,rtp->seq_number);
if (qempty(q)) {
putq(q,mp);
return;
}
tmp=qlast(q);
/* we look at the queue from bottom to top, because enqueued packets have a better chance
to be enqueued at the bottom, since there are surely newer */
while (!qend(q,tmp))
{
tmprtp=(rtp_header_t*)tmp->b_rptr;
ortp_debug("rtp_putq(): Seeing packet with seq=%i",tmprtp->seq_number);
if (rtp->seq_number == tmprtp->seq_number)
{
/* this is a duplicated packet. Don't queue it */
ortp_debug("rtp_putq: duplicated message.");
freemsg(mp);
return;
}else if (RTP_SEQ_IS_GREATER(rtp->seq_number,tmprtp->seq_number)){
insq(q,tmp->b_next,mp);
return;
}
tmp=tmp->b_prev;
}
/* this packet is the oldest, it has to be
placed on top of the queue */
insq(q,qfirst(q),mp);
}
mblk_t *rtp_getq(queue_t *q,guint32 timestamp, int *rejected)
{
mblk_t *tmp,*ret=NULL,*old;
rtp_header_t *tmprtp;
guint32 oldest;
guint32 ts_found=0;
*rejected=0;
ortp_debug("rtp_getq(): Timestamp %i wanted.",timestamp);
if (qempty(q))
{
/*ortp_debug("rtp_getq: q is empty.");*/
return NULL;
}
/* prevent somebody to ask for a timestamp that is older than the oldest of the queue */
oldest=((rtp_header_t*) qfirst(q)->b_rptr)->timestamp;
if (RTP_TIMESTAMP_IS_STRICTLY_NEWER_THAN(oldest,timestamp))
{
ortp_debug("rtp_getq(): asking for too old packet ! oldest=%i",oldest);
return NULL;
}
ret=NULL;
old=NULL;
/* return the packet with ts just equal or older than the asked timestamp */
while ((tmp=qfirst(q))!=NULL)
{
tmprtp=(rtp_header_t*)tmp->b_rptr;
ortp_debug("rtp_getq: Seeing packet with ts=%i",tmprtp->timestamp);
if ( RTP_TIMESTAMP_IS_NEWER_THAN(timestamp,tmprtp->timestamp) )
{
if (ret!=NULL && tmprtp->timestamp==ts_found) {
/* we've found two packets with same timestamp. return the first one */
break;
}
if (old!=NULL) {
ortp_debug("rtp_getq: discarding too old packet with ts=%i",ts_found);
(*rejected)++;
freemsg(old);
}
ret=getq(q); /* dequeue the packet, since it has an interesting timestamp*/
ts_found=tmprtp->timestamp;
ortp_debug("rtp_getq: Found packet with ts=%i",tmprtp->timestamp);
old=ret;
}
else
{
break;
}
}
return ret;
}
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