From 278d7850c768e06446e3c8bccf98b5f881163002 Mon Sep 17 00:00:00 2001
From: marco <49691247+marcoSchr@users.noreply.github.com>
Date: Fri, 18 Aug 2023 12:51:41 +0200
Subject: [PATCH] M17: add data structures for GNSS and extended callsign
 metadata.

---
 .../include/protocols/M17/M17Datatypes.hpp    | 92 +++++++++++++++++--
 openrtx/src/rtx/OpMode_M17.cpp                |  6 +-
 2 files changed, 88 insertions(+), 10 deletions(-)

diff --git a/openrtx/include/protocols/M17/M17Datatypes.hpp b/openrtx/include/protocols/M17/M17Datatypes.hpp
index c2a424fd..b5b59fa9 100644
--- a/openrtx/include/protocols/M17/M17Datatypes.hpp
+++ b/openrtx/include/protocols/M17/M17Datatypes.hpp
@@ -32,12 +32,91 @@ namespace M17
 {
 
 using call_t    = std::array< uint8_t, 6 >;    // Data type for encoded callsign
-using meta_t    = std::array< uint8_t, 14 >;   // Data type for LSF metadata field
 using payload_t = std::array< uint8_t, 16 >;   // Data type for frame payload field
 using lich_t    = std::array< uint8_t, 12 >;   // Data type for Golay(24,12) encoded LICH data
 using frame_t   = std::array< uint8_t, 48 >;   // Data type for a full M17 data frame, including sync word
 using syncw_t   = std::array< uint8_t, 2  >;   // Data type for a sync word
 
+enum M17DataMode
+{
+    M17_DATAMODE_PACKET = 0,
+    M17_DATAMODE_STREAM = 1
+};
+
+enum M17DataType
+{
+    M17_DATATYPE_DATA       = 1,
+    M17_DATATYPE_VOICE      = 2,
+    M17_DATATYPE_VOICE_DATA = 3
+};
+
+enum M17EncyptionType
+{
+    M17_ENCRYPTION_NONE      = 0,
+    M17_ENCRYPTION_AES       = 1,
+    M17_ENCRYPTION_SCRAMBLER = 2,
+    M17_ENCRYPTION_OTHER     = 3,
+};
+
+enum M17MetaType
+{
+    M17_META_TEXT          = 0,
+    M17_META_GNSS          = 1,
+    M17_META_EXTD_CALLSIGN = 2,
+};
+
+enum M17ScramblingType
+{
+    M17_SCRAMBLING_8BIT     = 0,
+    M17_SCRAMBLING_16BIT    = 1,
+    M17_SCRAMBLING_24BIT    = 2,
+};
+
+
+/**
+ * Data structure for M17 GNSS metadata field.
+ */
+typedef struct __attribute__((packed))
+{
+    uint8_t  data_src;          //< Data source
+    uint8_t  station_type;      //< Station type
+    uint8_t  lat_deg;           //< Latitude, whole number
+    uint16_t lat_dec;           //< Latitude, decimal part multiplied by 65535
+    uint8_t  lon_deg;           //< Longitude, whole number
+    uint16_t lon_dec;           //< Longitude, decimal part multiplied by 65535
+    uint8_t  lat_sign  : 1;     //< Latitude N/S: 0 = north, 1 = south
+    uint8_t  lon_sign  : 1;     //< Longitude E/W: 0 = east, 1 = west
+    uint8_t  alt_valid : 1;     //< Altitude data valid
+    uint8_t  spd_valid : 1;     //< Speed data valid
+    uint8_t  _unused   : 4;
+    uint16_t altitude;          //< Altitude above sea level in feet + 1500
+    uint16_t bearing;           //< Bearing in degrees, whole number
+    uint8_t  speed;             //< Speed in mph, whole number
+}
+gnssData_t;
+
+/**
+ * Data structure for M17 extended callsign metadata field.
+ */
+typedef struct __attribute__((packed))
+{
+    call_t   call1;
+    call_t   call2;
+    uint16_t _unused;
+}
+extdCall_t;
+
+/**
+ * Data structure for M17 LSF metadata field.
+ */
+typedef union
+{
+    extdCall_t extended_call_sign;
+    gnssData_t gnss_data;
+    uint8_t    raw_data[14];
+}
+meta_t;
+
 /**
  * This structure provides bit field definitions for the "TYPE" field
  * contained in an M17 Link Setup Frame.
@@ -46,19 +125,18 @@ typedef union
 {
     struct __attribute__((packed))
     {
-        uint16_t stream     : 1;    //< Packet/stream indicator: 0 = packet, 1 = stream
+        uint16_t dataMode   : 1;    //< Packet/stream indicator: 0 = packet, 1 = stream
         uint16_t dataType   : 2;    //< Data type indicator
         uint16_t encType    : 2;    //< Encryption type
         uint16_t encSubType : 2;    //< Encryption subtype
         uint16_t CAN        : 4;    //< Channel Access Number
-        uint16_t            : 4;    //< Reserved, padding to 16 bit
-    }
-    fields;
+        uint16_t            : 5;    //< Reserved, padding to 16 bit
+    } fields;
 
     uint16_t value;
 }
 streamType_t;
 
-}      // namespace M17
+}  // namespace M17
 
-#endif // M17_DATATYPES_H
+#endif  // M17_DATATYPES_H
diff --git a/openrtx/src/rtx/OpMode_M17.cpp b/openrtx/src/rtx/OpMode_M17.cpp
index 6bde9d6c..e2fcd3ba 100644
--- a/openrtx/src/rtx/OpMode_M17.cpp
+++ b/openrtx/src/rtx/OpMode_M17.cpp
@@ -224,9 +224,9 @@ void OpMode_M17::txState(rtxStatus_t *const status)
         if(!dst.empty()) lsf.setDestination(dst);
 
         streamType_t type;
-        type.fields.stream   = 1;             // Stream
-        type.fields.dataType = 2;             // Voice data
-        type.fields.CAN      = status->can;   // Channel access number
+        type.fields.dataMode = M17_DATAMODE_STREAM;     // Stream
+        type.fields.dataType = M17_DATATYPE_VOICE;      // Voice data
+        type.fields.CAN      = status->can;             // Channel access number
 
         lsf.setType(type);
         lsf.updateCrc();