Added EXTENDED_SEQUENCE_NUMBERS option

Added support for extended sequence numbers, which is a non-standard way to
increase the number of bits (from 8 to 12) for sequence numbers in AVTP
frames.  This is useful for Wi-Fi with retries, which can drop large numbers
of sequential frames.
To enable this feature, uncomment the EXTENDED_SEQUENCE_NUMBERS define.  The
feature is currently disabled.

4 files changed, 80 insertions, 19 deletions

diff --git a/lib/avtp_pipeline/avtp/openavb_avtp.c b/lib/avtp_pipeline/avtp/openavb_avtp.c
index cfea6adc..a753dff0 100644
--- a/lib/avtp_pipeline/avtp/openavb_avtp.c
+++ b/lib/avtp_pipeline/avtp/openavb_avtp.c
@@ -322,12 +322,23 @@ static openavbRC fillAvtpHdr(avtp_stream_t *pStream, U8 *pFill)
 			// - 1 bit		tv (timestamp valid)		= 1
 			// TODO: set mr correctly
 			*pFill++ = 0x81;
+#ifdef EXTENDED_SEQUENCE_NUMBERS
+			// - 8 bits		sequence num				= increments with each frame
+			*pFill++ = (pStream->avtp_sequence_num & 0x00FF);
+			// - 4 bits		upper bits of sequence num  = increments every 256 frames
+			// - 1 bit		using extended seq numbers	= 1
+			// - 2 bits		reserved					= 0
+			// - 1 bit		tu (timestamp uncertain)	= 1 when no PTP sync
+			// TODO: set tu correctly
+			*pFill++ = (U8) ((pStream->avtp_sequence_num & 0x0F00) >> 4) | 0x08;
+#else
 			// - 8 bits		sequence num				= increments with each frame
 			*pFill++ = pStream->avtp_sequence_num;
-			// - 7 bits		reserved					= 0;
+			// - 7 bits		reserved					= 0
 			// - 1 bit		tu (timestamp uncertain)	= 1 when no PTP sync
 			// TODO: set tu correctly
 			*pFill++ = 0;
+#endif
 			// - 8 bytes    stream_id
 			memcpy(pFill, (U8 *)&pStream->streamIDnet, 8);
 			break;
@@ -424,7 +435,11 @@ openavbRC openavbAvtpTx(void *pv, bool bSend, bool txBlockingInIntf)
 			}
 
 			// Increment the sequence number now that we are sure this is a good packet.
+#ifdef EXTENDED_SEQUENCE_NUMBERS
+			pStream->avtp_sequence_num = ((pStream->avtp_sequence_num + 1) & 0x0FFF);
+#else
 			pStream->avtp_sequence_num++;
+#endif
 
 			// Mirror the frame.
 			int i;
@@ -544,8 +559,13 @@ static void x_avtpRxFrame(avtp_stream_t *pStream, U8 *pFrame, U32 frameLen)
 {
 	AVB_TRACE_ENTRY(AVB_TRACE_AVTP_DETAIL);
 	IF_LOG_INTERVAL(4096) AVB_LOGF_DEBUG("pFrame=%p, len=%u", pFrame, frameLen);
-	U8 subtype, flags, flags2, rxSeq, nLost, avtpVersion;
+	U8 subtype, flags, flags2, avtpVersion;
 	U8 *pRead = pFrame;
+#ifdef EXTENDED_SEQUENCE_NUMBERS
+	U16 rxSeq, nLost;
+#else
+	U8 rxSeq, nLost;
+#endif
 
 	// AVTP Header
 	//
@@ -561,23 +581,53 @@ static void x_avtpRxFrame(avtp_stream_t *pStream, U8 *pFrame, U32 frameLen)
 
 			rxSeq = *pRead++;
 
-			if (pStream->nLost == -1) {
-				// first frame received, don't check for mismatch
-				pStream->nLost = 0;
-			}
-			else if (pStream->avtp_sequence_num != rxSeq) {
-				nLost = (rxSeq - pStream->avtp_sequence_num)
-					+ (rxSeq < pStream->avtp_sequence_num ? 256 : 0);
-				AVB_LOGF_INFO("AVTP sequence mismatch: expected: %3u,\tgot: %3u,\tlost %3d",
-					pStream->avtp_sequence_num, rxSeq, nLost);
-				pStream->nLost += nLost;
-
-				// Notify the map that frames were lost.
-				if (pStream->pMapCB->map_rx_lost_cb) {
-					pStream->pMapCB->map_rx_lost_cb(pStream->pMediaQ, nLost);
+#ifdef EXTENDED_SEQUENCE_NUMBERS
+			if ((*pRead & 0x08) != 0) {
+				// Get the upper 4 bits of the sequence number.
+				rxSeq |= (((U16) (*pRead & 0xF0)) << 4);
+
+				if (pStream->nLost == -1) {
+					// first frame received, don't check for mismatch
+					pStream->nLost = 0;
+				}
+				else if (pStream->avtp_sequence_num != rxSeq) {
+					nLost = (rxSeq - pStream->avtp_sequence_num)
+						+ (rxSeq < pStream->avtp_sequence_num ? 0x1000 : 0);
+					AVB_LOGF_INFO("AVTP sequence mismatch: expected: %4u,\tgot: %4u,\tlost %4d",
+						pStream->avtp_sequence_num, rxSeq, nLost);
+					pStream->nLost += nLost;
+
+					// Notify the map that frames were lost.
+					if (pStream->pMapCB->map_rx_lost_cb) {
+						pStream->pMapCB->map_rx_lost_cb(pStream->pMediaQ, nLost);
+					}
+				}
+				pStream->avtp_sequence_num = ((rxSeq + 1) & 0x0FFF);
+			} else
+#endif
+			{
+				if (pStream->nLost == -1) {
+					// first frame received, don't check for mismatch
+					pStream->nLost = 0;
+				}
+				else if (pStream->avtp_sequence_num != rxSeq) {
+					nLost = (rxSeq - pStream->avtp_sequence_num)
+						+ (rxSeq < pStream->avtp_sequence_num ? 0x100 : 0);
+					AVB_LOGF_INFO("AVTP sequence mismatch: expected: %3u,\tgot: %3u,\tlost %3d",
+						pStream->avtp_sequence_num, rxSeq, nLost);
+					pStream->nLost += nLost;
+
+					// Notify the map that frames were lost.
+					if (pStream->pMapCB->map_rx_lost_cb) {
+						pStream->pMapCB->map_rx_lost_cb(pStream->pMediaQ, nLost);
+					}
 				}
+#ifdef EXTENDED_SEQUENCE_NUMBERS
+				pStream->avtp_sequence_num = ((rxSeq + 1) & 0x00FF);
+#else
+				pStream->avtp_sequence_num = rxSeq + 1;
+#endif
 			}
-			pStream->avtp_sequence_num = rxSeq + 1;
 
 			pStream->bytes += frameLen;
 
diff --git a/lib/avtp_pipeline/avtp/openavb_avtp.h b/lib/avtp_pipeline/avtp/openavb_avtp.h
index 71139271..eb163373 100644
--- a/lib/avtp_pipeline/avtp/openavb_avtp.h
+++ b/lib/avtp_pipeline/avtp/openavb_avtp.h
@@ -83,6 +83,13 @@ typedef struct {
 } avtp_state_t;
 
 
+/* If EXTENDED_SEQUENCE_NUMBERS is defined, uses the 4 most significant bits of the reserved space
+ *  immediately following the sequence_num value to allow for larger sequence numbers.
+ * The bit following those 4 bits is also set to indicate that
+ *  extended sequence numbers are in use.
+ */
+//#define EXTENDED_SEQUENCE_NUMBERS
+
 /* Info associated with an AVTP stream (RX or TX).
  *
  * The void* handle that is returned to the client
@@ -117,7 +124,11 @@ typedef struct
 	// Max frame size
 	U16 frameLen;
 	// AVTP sequence number
+#ifdef EXTENDED_SEQUENCE_NUMBERS
+	U16 avtp_sequence_num;
+#else
 	U8 avtp_sequence_num;
+#endif
 	// Paused state of the stream
 	bool bPause;
 	// Encapsulation-specific state information
diff --git a/lib/avtp_pipeline/include/openavb_map_pub.h b/lib/avtp_pipeline/include/openavb_map_pub.h
index 8e4abeea..feb8a9e5 100755
--- a/lib/avtp_pipeline/include/openavb_map_pub.h
+++ b/lib/avtp_pipeline/include/openavb_map_pub.h
@@ -141,7 +141,7 @@ typedef bool (*openavb_map_rx_cb_t)(media_q_t *pMediaQ, U8 *pData, U32 datalen);
  * \param pMediaQ A pointer to the media queue for this stream
  * \param numLost The number of sequence numbers missing (i.e. number of lost packets)
  */
-typedef bool (*openavb_map_rx_lost_cb_t)(media_q_t *pMediaQ, U8 numLost);
+typedef bool (*openavb_map_rx_lost_cb_t)(media_q_t *pMediaQ, U16 numLost);
 
 /** This callback will be called when the stream is closing.
  *
diff --git a/lib/avtp_pipeline/map_aaf_audio/openavb_map_aaf_audio.c b/lib/avtp_pipeline/map_aaf_audio/openavb_map_aaf_audio.c
index e3a5906a..12636619 100755
--- a/lib/avtp_pipeline/map_aaf_audio/openavb_map_aaf_audio.c
+++ b/lib/avtp_pipeline/map_aaf_audio/openavb_map_aaf_audio.c
@@ -1063,7 +1063,7 @@ bool openavbMapAVTPAudioRxCB(media_q_t *pMediaQ, U8 *pData, U32 dataLen)
 }
 
 // This callback occurs when running as a listener and data is not available.
-bool openavbMapAVTPAudioRxLostCB(media_q_t *pMediaQ, U8 numLost)
+bool openavbMapAVTPAudioRxLostCB(media_q_t *pMediaQ, U16 numLost)
 {
 	AVB_TRACE_ENTRY(AVB_TRACE_MAP_DETAIL);