[vlc-devel] [PATCH] rtp sout: ensure seq value in rtsp is accurate

[Pierre Ynard]

Handle caching and fix race conditions


diff --git a/modules/stream_out/rtp.c b/modules/stream_out/rtp.c
index ff6388f..805b1ec 100644
--- a/modules/stream_out/rtp.c
+++ b/modules/stream_out/rtp.c
@@ -312,6 +312,9 @@ struct sout_stream_id_t
     uint8_t     i_payload_type;
     uint8_t     ssrc[4];
 
+    /* for rtsp */
+    uint16_t    i_seq_sent_next;
+
     /* for sdp */
     const char  *psz_enc;
     char        *psz_fmtp;
@@ -925,6 +928,8 @@ static sout_stream_id_t *Add( sout_stream_t *p_stream, es_format_t *p_fmt )
     vlc_rand_bytes (&id->i_sequence, sizeof (id->i_sequence));
     vlc_rand_bytes (id->ssrc, sizeof (id->ssrc));
 
+    id->i_seq_sent_next = id->i_sequence;
+
     id->psz_enc    = NULL;
     id->psz_fmtp   = NULL;
     id->i_clock_rate = 90000; /* most common case for video */
@@ -1037,7 +1042,7 @@ static sout_stream_id_t *Add( sout_stream_t *p_stream, es_format_t *p_fmt )
                  * packets in case of rtcp-mux) */
                 setsockopt (fd, SOL_SOCKET, SO_RCVBUF, &(int){ 0 },
                             sizeof (int));
-                rtp_add_sink( id, fd, p_sys->rtcp_mux );
+                rtp_add_sink( id, fd, p_sys->rtcp_mux, NULL );
             }
         }
 
@@ -1596,6 +1601,7 @@ static void* ThreadSend( vlc_object_t *p_this )
 
             deadv[deadc++] = id->sinkv[i].rtp_fd;
         }
+        id->i_seq_sent_next = ((uint16_t *) out->p_buffer)[1] + 1;
         vlc_mutex_unlock( &id->lock_sink );
         block_Release( out );
 
@@ -1623,7 +1629,7 @@ static void *rtp_listen_thread( void *data )
         if( fd == -1 )
             continue;
         int canc = vlc_savecancel( );
-        rtp_add_sink( id, fd, true );
+        rtp_add_sink( id, fd, true, NULL );
         vlc_restorecancel( canc );
     }
 
@@ -1631,7 +1637,7 @@ static void *rtp_listen_thread( void *data )
 }
 
 
-int rtp_add_sink( sout_stream_id_t *id, int fd, bool rtcp_mux )
+int rtp_add_sink( sout_stream_id_t *id, int fd, bool rtcp_mux, uint16_t *seq )
 {
     rtp_sink_t sink = { fd, NULL };
     sink.rtcp = OpenRTCP( VLC_OBJECT( id->p_stream ), fd, IPPROTO_UDP,
@@ -1641,6 +1647,8 @@ int rtp_add_sink( sout_stream_id_t *id, int fd, bool rtcp_mux )
 
     vlc_mutex_lock( &id->lock_sink );
     INSERT_ELEM( id->sinkv, id->sinkc, id->sinkc, sink );
+    if( seq != NULL )
+        *seq = id->i_seq_sent_next;
     vlc_mutex_unlock( &id->lock_sink );
     return VLC_SUCCESS;
 }
@@ -1666,11 +1674,16 @@ void rtp_del_sink( sout_stream_id_t *id, int fd )
     net_Close( sink.rtp_fd );
 }
 
-uint16_t rtp_get_seq( const sout_stream_id_t *id )
+uint16_t rtp_get_seq( sout_stream_id_t *id )
 {
-    /* This will return values for the next packet.
-     * Accounting for caching would not be totally trivial. */
-    return id->i_sequence;
+    /* This will return values for the next packet. */
+    uint16_t seq;
+
+    vlc_mutex_lock( &id->lock_sink );
+    seq = id->i_seq_sent_next;
+    vlc_mutex_unlock( &id->lock_sink );
+
+    return seq;
 }
 
 /* FIXME: this is pretty bad - if we remove and then insert an ES
diff --git a/modules/stream_out/rtp.h b/modules/stream_out/rtp.h
index aec9dde..5372146 100644
--- a/modules/stream_out/rtp.h
+++ b/modules/stream_out/rtp.h
@@ -36,9 +36,9 @@ void RtspDelId( rtsp_stream_t *rtsp, rtsp_stream_id_t * );
 
 char *SDPGenerate( const sout_stream_t *p_stream, const char *rtsp_url );
 
-int rtp_add_sink( sout_stream_id_t *id, int fd, bool rtcp_mux );
+int rtp_add_sink( sout_stream_id_t *id, int fd, bool rtcp_mux, uint16_t *seq );
 void rtp_del_sink( sout_stream_id_t *id, int fd );
-uint16_t rtp_get_seq( const sout_stream_id_t *id );
+uint16_t rtp_get_seq( sout_stream_id_t *id );
 unsigned rtp_get_num( const sout_stream_id_t *id );
 
 /* RTP packetization */
diff --git a/modules/stream_out/rtsp.c b/modules/stream_out/rtsp.c
index 61d81fa..a8e3027 100644
--- a/modules/stream_out/rtsp.c
+++ b/modules/stream_out/rtsp.c
@@ -646,16 +646,19 @@ static int RtspHandler( rtsp_stream_t *rtsp, rtsp_stream_id_t *id,
                     rtsp_strack_t *tr = ses->trackv + i;
                     if( ( id == NULL ) || ( tr->id == id->sout_id ) )
                     {
+                        uint16_t seq;
                         if( !tr->playing )
                         {
                             tr->playing = true;
-                            rtp_add_sink( tr->id, tr->fd, false );
+                            rtp_add_sink( tr->id, tr->fd, false, &seq );
                         }
+                        else
+                            seq = rtp_get_seq( tr->id );
                         infolen += sprintf( info + infolen,
                                             "url=%s/trackID=%u;seq=%u, ",
                                             control,
                                             rtp_get_num( tr->id ),
-                                            rtp_get_seq( tr->id ) );
+                                            seq );
                     }
                 }
                 if( infolen > 0 )


Regards,

-- 
Pierre Ynard
"Une âme dans un corps, c'est comme un dessin sur une feuille de papier."