From b6f007a104be2015e2cd075483e17c3e9ca655c1 Mon Sep 17 00:00:00 2001
From: Determinant <tederminant@gmail.com>
Date: Mon, 23 Mar 2020 18:53:24 -0400
Subject: [PATCH 01/14] WIP: support stratux protocol

---
 dump1090.c |   5 ++
 dump1090.h |   4 +-
 net_io.c   | 227 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 235 insertions(+), 1 deletion(-)

diff --git a/dump1090.c b/dump1090.c
index 2506e8c..356c1f5 100644
--- a/dump1090.c
+++ b/dump1090.c
@@ -116,6 +116,7 @@ void modesInitConfig(void) {
     Modes.net_output_sbs_ports    = strdup("30003");
     Modes.net_input_beast_ports   = strdup("30004,30104");
     Modes.net_output_beast_ports  = strdup("30005");
+    Modes.net_output_stratux_ports= strdup("30006");
     Modes.interactive_display_ttl = MODES_INTERACTIVE_DISPLAY_TTL;
     Modes.json_interval           = 1000;
     Modes.json_location_accuracy  = 1;
@@ -299,6 +300,7 @@ void showHelp(void) {
 "--net-sbs-port <ports>   TCP BaseStation output listen ports (default: 30003)\n"
 "--net-bi-port <ports>    TCP Beast input listen ports  (default: 30004,30104)\n"
 "--net-bo-port <ports>    TCP Beast output listen ports (default: 30005)\n"
+"--net-stratux-port <ports>   TCP Stratux output listen ports (default: 30006)\n"
 "--net-ro-size <size>     TCP output minimum size (default: 0)\n"
 "--net-ro-interval <rate> TCP output memory flush rate in seconds (default: 0)\n"
 "--net-heartbeat <rate>   TCP heartbeat rate in seconds (default: 60 sec; 0 to disable)\n"
@@ -532,6 +534,9 @@ int main(int argc, char **argv) {
         } else if (!strcmp(argv[j],"--net-sbs-port") && more) {
             free(Modes.net_output_sbs_ports);
             Modes.net_output_sbs_ports = strdup(argv[++j]);
+        } else if (!strcmp(argv[j],"--net-stratux-port") && more) {
+            free(Modes.net_output_stratux_ports);
+            Modes.net_output_stratux_ports = strdup(argv[++j]);
         } else if (!strcmp(argv[j],"--net-buffer") && more) {
             Modes.net_sndbuf_size = atoi(argv[++j]);
         } else if (!strcmp(argv[j],"--net-verbatim")) {
diff --git a/dump1090.h b/dump1090.h
index 5c7cf73..ec45d8e 100644
--- a/dump1090.h
+++ b/dump1090.h
@@ -52,7 +52,7 @@
 
 // Default version number, if not overriden by the Makefile
 #ifndef MODES_DUMP1090_VERSION
-# define MODES_DUMP1090_VERSION     "v1.13-custom"
+# define MODES_DUMP1090_VERSION     "v1.13-stratux"
 #endif
 
 #ifndef MODES_DUMP1090_VARIANT
@@ -332,6 +332,7 @@ struct {                             // Internal state
     struct net_writer beast_verbatim_out;        // Beast-format output, verbatim mode
     struct net_writer beast_cooked_out;          // Beast-format output, "cooked" mode
     struct net_writer sbs_out;                   // SBS-format output
+    struct net_writer stratux_out;               // Stratux-format output
     struct net_writer fatsv_out;                 // FATSV-format output
 
 #ifdef _WIN32
@@ -354,6 +355,7 @@ struct {                             // Internal state
     char *net_output_raw_ports;      // List of raw output TCP ports
     char *net_input_raw_ports;       // List of raw input TCP ports
     char *net_output_sbs_ports;      // List of SBS output TCP ports
+    char *net_output_stratux_ports;  // List of Stratux output TCP ports
     char *net_input_beast_ports;     // List of Beast input TCP ports
     char *net_output_beast_ports;    // List of Beast output TCP ports
     char *net_bind_address;          // Bind address
diff --git a/net_io.c b/net_io.c
index 6375f01..6c72595 100644
--- a/net_io.c
+++ b/net_io.c
@@ -77,6 +77,7 @@ static void moveNetClient(struct client *c, struct net_service *new_service);
 static void send_raw_heartbeat(struct net_service *service);
 static void send_beast_heartbeat(struct net_service *service);
 static void send_sbs_heartbeat(struct net_service *service);
+static void send_stratux_heartbeat(struct net_service *service);
 
 static void writeBeastMessage(struct net_writer *writer, uint64_t timestamp, double signalLevel, unsigned char *msg, int msgLen);
 
@@ -268,6 +269,9 @@ void modesInitNet(void) {
     s = serviceInit("Basestation TCP output", &Modes.sbs_out, send_sbs_heartbeat, READ_MODE_IGNORE, NULL, NULL);
     serviceListen(s, Modes.net_bind_address, Modes.net_output_sbs_ports);
 
+    s = serviceInit("Stratux TCP output", &Modes.stratux_out, send_stratux_heartbeat, READ_MODE_IGNORE, NULL, NULL);
+    serviceListen(s, Modes.net_bind_address, Modes.net_output_stratux_ports);
+
     s = serviceInit("Raw TCP input", NULL, NULL, READ_MODE_ASCII, "\n", decodeHexMessage);
     serviceListen(s, Modes.net_bind_address, Modes.net_input_raw_ports);
 
@@ -776,6 +780,228 @@ static void send_sbs_heartbeat(struct net_service *service)
     completeWrite(service->writer, data + len);
 }
 
+////////////////////////////////////////// Start Stratux block 
+
+//
+//=========================================================================
+//
+// Write Stratux output to TCP clients
+// The message structure mm->bFlags tells us what has been updated by this message
+//
+// Output format is a JSON representation of a subset of the fields used in the
+// Stratux traffic structure.
+//
+static void modesSendStratuxOutput(struct modesMessage *mm, struct aircraft *a) {
+    char *p;
+    struct timespec now;
+    struct tm    stTime_receive, stTime_now;
+    int          msgType;
+
+    // Send all addresses, since we want to see TIS-B data.
+    //if (mm->addr & MODES_NON_ICAO_ADDRESS)
+    //    return;
+
+    p = prepareWrite(&Modes.stratux_out, 1000); // larger buffer size needed vs SBS
+    if (!p)
+        return;
+
+
+    // Decide on the basic SBS Message Type
+    if        ((mm->msgtype ==  4) || (mm->msgtype == 20)) {
+        msgType = 5;
+    } else if ((mm->msgtype ==  5) || (mm->msgtype == 21)) {
+        msgType = 6;
+    } else if ((mm->msgtype ==  0) || (mm->msgtype == 16)) {
+        msgType = 7;
+    } else if  (mm->msgtype == 11) {
+        msgType = 8;
+    } else if ((mm->msgtype != 17) && (mm->msgtype != 18)) {
+        return;
+    } else if ((mm->metype >= 1) && (mm->metype <=  4)) {
+        msgType = 1;
+    } else if ((mm->metype >= 5) && (mm->metype <=  8)) {
+        if (mm->cpr_decoded)
+            {msgType = 2;}
+        else
+            {msgType = 7;}
+    } else if ((mm->metype >= 9) && (mm->metype <= 18)) {
+        if (mm->cpr_decoded)
+            {msgType = 3;}
+        else
+            {msgType = 7;}
+    } else if ((mm->metype == 29) || (mm->metype == 31)) {
+		msgType = 9; // new message type for target state and operational status messages
+    } else if (mm->metype !=  19) {
+        return;
+    } else if ((mm->mesub == 1) || (mm->mesub == 2)) {
+        msgType = 4;
+    } else {
+        return;
+    }
+
+    // Begin populating the traffic.go fields.
+	// ICAO address, Mode S message types, and signal level
+    
+    int cacf = 0; // overload the JSON "CA" field to report CA (DF11 or DF17), CF (DF18), or zero (all other DF types)
+    if ((mm->msgtype == 11) || (mm->msgtype == 17)) {
+        cacf = mm->CA;
+    } else if (mm->msgtype == 18) {
+        cacf = mm->CF;
+    }
+    
+	p += sprintf(p, "{\"Icao_addr\":%d,\"DF\":%d,\"CA\":%d,\"TypeCode\":%d,\"SubtypeCode\":%d,\"SBS_MsgType\":%d,\"SignalLevel\":%f,",mm->addr, mm->msgtype, cacf, mm->metype,  mm->mesub, msgType, mm->signalLevel); // what precision and range is needed for RSSI?
+    
+ 	// Callsign
+	if (mm->callsign_valid) {
+		p += sprintf(p, "\"Tail\":\"%s\",", mm->callsign);
+	} else {
+		p += sprintf(p, "\"Tail\":null,");
+	}   
+    
+    //Squawk
+    if (mm->squawk_valid) {
+        p += sprintf(p, "\"Squawk\":%x,", mm->squawk);
+    }
+    else {
+        p += sprintf(p, "\"Squawk\":null,");
+    }
+    
+    // Emitter type
+	int emitter = 0;
+	int setEmitter = 0;
+	if ((mm->msgtype ==  17) || (mm->msgtype = 18)) {
+		switch (mm->metype) {
+			case 1:
+				emitter = ((mm->mesub) | 0x18);
+				setEmitter = 1;
+                break;
+			case 2:
+				emitter = ((mm->mesub) | 0x10);
+				setEmitter = 1;
+                break;
+			case 3:
+				emitter = ((mm->mesub) | 0x08);
+				setEmitter = 1;
+                break;
+			case 4:
+				emitter = (mm->mesub);
+				setEmitter = 1;
+                break;
+		}
+	}
+	
+	if (setEmitter) {
+		p += sprintf(p, "\"Emitter_category\":%d,", emitter);
+	} else {
+		p += sprintf(p, "\"Emitter_category\":null,");
+	}
+    
+    // OnGround
+    if (mm->airground == AG_GROUND) {
+        p += sprintf(p, "\"OnGround\":true,");
+    } else if (mm->airground == AG_AIRBORNE) {
+        p += sprintf(p, "\"OnGround\":false,");
+    } else {
+        p += sprintf(p, "\"OnGround\":null,");
+    }
+    
+    // Position and position valid flag
+	if (mm->cpr_decoded) {
+		p += sprintf(p, "\"Lat\":%.6f,\"Lng\":%.6f,\"Position_valid\":true,", mm->decoded_lat, mm->decoded_lon);
+	} else {
+		p += sprintf(p, "\"Lat\":null,\"Lng\":null,\"Position_valid\":false,");
+	}
+	
+    // Navigation Accuracy Category - Position
+    if (mm->accuracy.nac_p_valid) {
+        p += sprintf(p, "\"NACp\":%d,", mm->accuracy.nac_p);
+    } else {
+	    p += sprintf(p, "\"NACp\":null,");
+    }
+    
+    bool alt_is_geom = false;
+	// Altitude
+	if (Modes.use_gnss && mm->altitude_geom_valid) {
+		p += sprintf(p, "\"Alt\":%d,",mm->altitude_geom);
+        alt_is_geom = true;
+    } else if (mm->altitude_baro_valid) {
+		p += sprintf(p, "\"Alt\":%d,",mm->altitude_baro);
+    } else {
+		p += sprintf(p, "\"Alt\":null,");
+    }
+    
+    // Altitude Source. True if altitude source is GNSS, false if pressure altitude.
+    if (alt_is_geom) {
+        p += sprintf(p, "\"AltIsGNSS\":true,");
+	} else {
+        p += sprintf(p, "\"AltIsGNSS\":false,");
+    }
+    // GNSS Alt Diff From Baro Alt
+    if (trackDataValid(&a->geom_delta_valid)) {
+        p += sprintf(p, "\"GnssDiffFromBaroAlt\":%d,",a->geom_delta);    // Verify that this is part of a and not mm
+    } else {
+        p += sprintf(p, "\"GnssDiffFromBaroAlt\":null,");
+    }
+    
+ 	//Vertical velocity
+	if (alt_is_geom) {
+        if (mm->geom_rate_valid)
+		    p += sprintf(p, "\"Vvel\":%d,", mm->geom_rate);
+        else
+		    p += sprintf(p,  "\"Vvel\":null,");
+    } else {
+        if (mm->baro_rate_valid)
+		    p += sprintf(p, "\"Vvel\":%d,", mm->baro_rate);
+	    else
+		    p += sprintf(p,  "\"Vvel\":null,");
+    }
+
+	// Ground speed and track
+    if (mm->gs_valid) {
+        p += sprintf(p, "\"Speed_valid\":true,\"Speed\":%.0f,", mm->gs.selected);
+    } else {
+        p += sprintf(p, "\"Speed_valid\":false,\"Speed\":null,"); 
+    }
+
+    if (mm->heading_valid && mm->heading_type == HEADING_GROUND_TRACK) {
+        p += sprintf(p, "\"Track\":%.0f,", mm->heading);
+    } else {
+        p += sprintf(p, "\"Track\":null,");
+    }
+
+    // Find current system time
+    clock_gettime(CLOCK_REALTIME, &now);
+    gmtime_r(&now.tv_sec, &stTime_now);  // we expect UTC 
+
+    // Find message reception time
+    time_t received = (time_t) (mm->sysTimestampMsg / 1000);
+    localtime_r(&received, &stTime_receive);
+
+    //Time message received (based on system clock). Format is 2016-02-20T06:35:43.155Z
+	p += sprintf(p, "\"Timestamp\":\"%04d-%02d-%02dT%02d:%02d:%02d.%03dZ\"", (stTime_receive.tm_year+1900),(stTime_receive.tm_mon+1), stTime_receive.tm_mday, stTime_receive.tm_hour, stTime_receive.tm_min, stTime_receive.tm_sec, (unsigned) (mm->sysTimestampMsg % 1000));
+    
+    p += sprintf(p, "}\r\n");
+
+    completeWrite(&Modes.stratux_out, p);
+}
+
+static void send_stratux_heartbeat(struct net_service *service)
+{
+    static char *heartbeat_message = "{\"Icao_addr\":134217727}\r\n";  // 0x07FFFFFF. Overflows 24-bit ICAO to signal invalic #, need to validate that this won't cause problems with traffic.go
+    char *data;
+    int len = strlen(heartbeat_message);
+
+    if (!service->writer)
+        return;
+
+    data = prepareWrite(service->writer, len);
+    if (!data)
+        return;
+
+    memcpy(data, heartbeat_message, len);
+    completeWrite(service->writer, data + len);
+}
+
 //
 //=========================================================================
 //
@@ -783,6 +1009,7 @@ void modesQueueOutput(struct modesMessage *mm, struct aircraft *a) {
 
     // Delegate to the format-specific outputs, each of which makes its own decision about filtering messages
     modesSendSBSOutput(mm, a);
+    modesSendStratuxOutput(mm, a);
     modesSendRawOutput(mm, a);
     modesSendBeastVerbatimOutput(mm, a);
     modesSendBeastCookedOutput(mm, a);

From 52338202d1d0783a23cba9d5313cd8c077d1d430 Mon Sep 17 00:00:00 2001
From: Determinant <tederminant@gmail.com>
Date: Tue, 24 Mar 2020 14:08:44 -0400
Subject: [PATCH 02/14] ...

---
 net_io.c | 20 ++++++++++++++++----
 1 file changed, 16 insertions(+), 4 deletions(-)

diff --git a/net_io.c b/net_io.c
index 6c72595..73ecff8 100644
--- a/net_io.c
+++ b/net_io.c
@@ -797,9 +797,21 @@ static void modesSendStratuxOutput(struct modesMessage *mm, struct aircraft *a)
     struct tm    stTime_receive, stTime_now;
     int          msgType;
 
-    // Send all addresses, since we want to see TIS-B data.
-    //if (mm->addr & MODES_NON_ICAO_ADDRESS)
-    //    return;
+    // We require a tracked aircraft for SBS output
+    if (!a)
+        return;
+
+    // Don't ever forward 2-bit-corrected messages via SBS output.
+    if (mm->correctedbits >= 2)
+        return;
+
+    // Don't ever forward mlat messages via SBS output.
+    if (mm->source == SOURCE_MLAT)
+        return;
+
+    // Don't ever send unreliable messages via SBS output
+    if (!mm->reliable && !a->reliable)
+        return;
 
     p = prepareWrite(&Modes.stratux_out, 1000); // larger buffer size needed vs SBS
     if (!p)
@@ -869,7 +881,7 @@ static void modesSendStratuxOutput(struct modesMessage *mm, struct aircraft *a)
     // Emitter type
 	int emitter = 0;
 	int setEmitter = 0;
-	if ((mm->msgtype ==  17) || (mm->msgtype = 18)) {
+	if ((mm->msgtype ==  17) || (mm->msgtype == 18)) {
 		switch (mm->metype) {
 			case 1:
 				emitter = ((mm->mesub) | 0x18);

From 2f9c3fe0e180ddd2286c224331d939e790d9895a Mon Sep 17 00:00:00 2001
From: Determinant <tederminant@gmail.com>
Date: Sat, 28 Mar 2020 15:23:30 -0400
Subject: [PATCH 03/14] clean up

---
 net_io.c | 283 +++++++++++++++++++++++++++++--------------------------
 1 file changed, 150 insertions(+), 133 deletions(-)

diff --git a/net_io.c b/net_io.c
index 73ecff8..d4ca0ff 100644
--- a/net_io.c
+++ b/net_io.c
@@ -780,16 +780,10 @@ static void send_sbs_heartbeat(struct net_service *service)
     completeWrite(service->writer, data + len);
 }
 
-////////////////////////////////////////// Start Stratux block 
-
 //
 //=========================================================================
 //
 // Write Stratux output to TCP clients
-// The message structure mm->bFlags tells us what has been updated by this message
-//
-// Output format is a JSON representation of a subset of the fields used in the
-// Stratux traffic structure.
 //
 static void modesSendStratuxOutput(struct modesMessage *mm, struct aircraft *a) {
     char *p;
@@ -813,11 +807,17 @@ static void modesSendStratuxOutput(struct modesMessage *mm, struct aircraft *a)
     if (!mm->reliable && !a->reliable)
         return;
 
+    //// For now, suppress non-ICAO addresses
+    //if (mm->addr & MODES_NON_ICAO_ADDRESS)
+    //    return;
+
     p = prepareWrite(&Modes.stratux_out, 1000); // larger buffer size needed vs SBS
     if (!p)
         return;
 
-
+    // NOTE: not sure about message types, so keep the original code from
+    // stratux/dump1090 as-is.
+    //
     // Decide on the basic SBS Message Type
     if        ((mm->msgtype ==  4) || (mm->msgtype == 20)) {
         msgType = 5;
@@ -842,7 +842,7 @@ static void modesSendStratuxOutput(struct modesMessage *mm, struct aircraft *a)
         else
             {msgType = 7;}
     } else if ((mm->metype == 29) || (mm->metype == 31)) {
-		msgType = 9; // new message type for target state and operational status messages
+        msgType = 9; // new message type for target state and operational status messages
     } else if (mm->metype !=  19) {
         return;
     } else if ((mm->mesub == 1) || (mm->mesub == 2)) {
@@ -852,146 +852,163 @@ static void modesSendStratuxOutput(struct modesMessage *mm, struct aircraft *a)
     }
 
     // Begin populating the traffic.go fields.
-	// ICAO address, Mode S message types, and signal level
-    
+    // ICAO address, Mode S message types, and signal level
+
     int cacf = 0; // overload the JSON "CA" field to report CA (DF11 or DF17), CF (DF18), or zero (all other DF types)
     if ((mm->msgtype == 11) || (mm->msgtype == 17)) {
         cacf = mm->CA;
     } else if (mm->msgtype == 18) {
         cacf = mm->CF;
     }
-    
-	p += sprintf(p, "{\"Icao_addr\":%d,\"DF\":%d,\"CA\":%d,\"TypeCode\":%d,\"SubtypeCode\":%d,\"SBS_MsgType\":%d,\"SignalLevel\":%f,",mm->addr, mm->msgtype, cacf, mm->metype,  mm->mesub, msgType, mm->signalLevel); // what precision and range is needed for RSSI?
-    
- 	// Callsign
-	if (mm->callsign_valid) {
-		p += sprintf(p, "\"Tail\":\"%s\",", mm->callsign);
-	} else {
-		p += sprintf(p, "\"Tail\":null,");
-	}   
-    
-    //Squawk
-    if (mm->squawk_valid) {
-        p += sprintf(p, "\"Squawk\":%x,", mm->squawk);
-    }
-    else {
-        p += sprintf(p, "\"Squawk\":null,");
-    }
-    
-    // Emitter type
-	int emitter = 0;
-	int setEmitter = 0;
-	if ((mm->msgtype ==  17) || (mm->msgtype == 18)) {
-		switch (mm->metype) {
-			case 1:
-				emitter = ((mm->mesub) | 0x18);
-				setEmitter = 1;
-                break;
-			case 2:
-				emitter = ((mm->mesub) | 0x10);
-				setEmitter = 1;
-                break;
-			case 3:
-				emitter = ((mm->mesub) | 0x08);
-				setEmitter = 1;
-                break;
-			case 4:
-				emitter = (mm->mesub);
-				setEmitter = 1;
-                break;
-		}
-	}
-	
-	if (setEmitter) {
-		p += sprintf(p, "\"Emitter_category\":%d,", emitter);
-	} else {
-		p += sprintf(p, "\"Emitter_category\":null,");
-	}
-    
-    // OnGround
-    if (mm->airground == AG_GROUND) {
-        p += sprintf(p, "\"OnGround\":true,");
-    } else if (mm->airground == AG_AIRBORNE) {
-        p += sprintf(p, "\"OnGround\":false,");
-    } else {
-        p += sprintf(p, "\"OnGround\":null,");
-    }
-    
-    // Position and position valid flag
-	if (mm->cpr_decoded) {
-		p += sprintf(p, "\"Lat\":%.6f,\"Lng\":%.6f,\"Position_valid\":true,", mm->decoded_lat, mm->decoded_lon);
-	} else {
-		p += sprintf(p, "\"Lat\":null,\"Lng\":null,\"Position_valid\":false,");
-	}
-	
-    // Navigation Accuracy Category - Position
-    if (mm->accuracy.nac_p_valid) {
-        p += sprintf(p, "\"NACp\":%d,", mm->accuracy.nac_p);
-    } else {
-	    p += sprintf(p, "\"NACp\":null,");
-    }
-    
-    bool alt_is_geom = false;
-	// Altitude
-	if (Modes.use_gnss && mm->altitude_geom_valid) {
-		p += sprintf(p, "\"Alt\":%d,",mm->altitude_geom);
-        alt_is_geom = true;
-    } else if (mm->altitude_baro_valid) {
-		p += sprintf(p, "\"Alt\":%d,",mm->altitude_baro);
-    } else {
-		p += sprintf(p, "\"Alt\":null,");
-    }
-    
-    // Altitude Source. True if altitude source is GNSS, false if pressure altitude.
-    if (alt_is_geom) {
-        p += sprintf(p, "\"AltIsGNSS\":true,");
-	} else {
-        p += sprintf(p, "\"AltIsGNSS\":false,");
-    }
-    // GNSS Alt Diff From Baro Alt
-    if (trackDataValid(&a->geom_delta_valid)) {
-        p += sprintf(p, "\"GnssDiffFromBaroAlt\":%d,",a->geom_delta);    // Verify that this is part of a and not mm
-    } else {
-        p += sprintf(p, "\"GnssDiffFromBaroAlt\":null,");
-    }
-    
- 	//Vertical velocity
-	if (alt_is_geom) {
-        if (mm->geom_rate_valid)
-		    p += sprintf(p, "\"Vvel\":%d,", mm->geom_rate);
-        else
-		    p += sprintf(p,  "\"Vvel\":null,");
-    } else {
-        if (mm->baro_rate_valid)
-		    p += sprintf(p, "\"Vvel\":%d,", mm->baro_rate);
-	    else
-		    p += sprintf(p,  "\"Vvel\":null,");
-    }
 
-	// Ground speed and track
-    if (mm->gs_valid) {
-        p += sprintf(p, "\"Speed_valid\":true,\"Speed\":%.0f,", mm->gs.selected);
-    } else {
-        p += sprintf(p, "\"Speed_valid\":false,\"Speed\":null,"); 
-    }
-
-    if (mm->heading_valid && mm->heading_type == HEADING_GROUND_TRACK) {
-        p += sprintf(p, "\"Track\":%.0f,", mm->heading);
-    } else {
-        p += sprintf(p, "\"Track\":null,");
-    }
+    p += sprintf(p,
+            "{\"Icao_addr\":%d,"
+            "\"DF\":%d,\"CA\":%d,"
+            "\"TypeCode\":%d,"
+            "\"SubtypeCode\":%d,"
+            "\"SBS_MsgType\":%d,"
+            "\"SignalLevel\":%f,",
+            mm->addr,
+            mm->msgtype, cacf,
+            mm->metype,
+            mm->mesub,
+            msgType,
+            mm->signalLevel); // what precision and range is needed for RSSI?
 
     // Find current system time
     clock_gettime(CLOCK_REALTIME, &now);
-    gmtime_r(&now.tv_sec, &stTime_now);  // we expect UTC 
+    gmtime_r(&now.tv_sec, &stTime_now);  // we expect UTC
 
     // Find message reception time
     time_t received = (time_t) (mm->sysTimestampMsg / 1000);
     localtime_r(&received, &stTime_receive);
 
-    //Time message received (based on system clock). Format is 2016-02-20T06:35:43.155Z
-	p += sprintf(p, "\"Timestamp\":\"%04d-%02d-%02dT%02d:%02d:%02d.%03dZ\"", (stTime_receive.tm_year+1900),(stTime_receive.tm_mon+1), stTime_receive.tm_mday, stTime_receive.tm_hour, stTime_receive.tm_min, stTime_receive.tm_sec, (unsigned) (mm->sysTimestampMsg % 1000));
-    
+    // Time message received (based on system clock). Format is 2016-02-20T06:35:43.155Z
+    p += sprintf(p, "\"Timestamp\":\"%04d-%02d-%02dT%02d:%02d:%02d.%03dZ\"", (stTime_receive.tm_year+1900),(stTime_receive.tm_mon+1), stTime_receive.tm_mday, stTime_receive.tm_hour, stTime_receive.tm_min, stTime_receive.tm_sec, (unsigned) (mm->sysTimestampMsg % 1000));
+
+    //// callsign
+    if (mm->callsign_valid)
+        p += sprintf(p, "\"Tail\":\"%s\",", mm->callsign);
+    else
+        p += sprintf(p, "\"Tail\":null,");
+
+    //// altitude & gnss
+    bool alt_is_geom = false;
+    if (Modes.use_gnss && mm->altitude_geom_valid) {
+        p += sprintf(p, "\"Alt\":%d,",mm->altitude_geom);
+        alt_is_geom = true;
+    } else if (mm->altitude_baro_valid)
+        p += sprintf(p, "\"Alt\":%d,",mm->altitude_baro);
+    else
+        p += sprintf(p, "\"Alt\":null,");
+
+    // altitude source
+    if (alt_is_geom)
+        p += sprintf(p, "\"AltIsGNSS\":true,");
+    else
+        p += sprintf(p, "\"AltIsGNSS\":false,");
+
+    // GNSS alt. delta From baro alt.
+    if (trackDataValid(&a->geom_delta_valid))
+        p += sprintf(p, "\"GnssDiffFromBaroAlt\":%d,",a->geom_delta);
+    else
+        p += sprintf(p, "\"GnssDiffFromBaroAlt\":null,");
+    ////
+
+    //// ground speed and track
+    if (mm->gs_valid)
+        p += sprintf(p, "\"Speed_valid\":true,\"Speed\":%.0f,", mm->gs.selected);
+    else
+        p += sprintf(p, "\"Speed_valid\":false,\"Speed\":null,");
+
+    //// ground heading
+    if (mm->heading_valid && mm->heading_type == HEADING_GROUND_TRACK)
+        p += sprintf(p, "\"Track\":%.0f,", mm->heading);
+    else
+        p += sprintf(p, "\"Track\":null,");
+
+    //// position
+    if (mm->cpr_decoded)
+        p += sprintf(p, "\"Lat\":%.6f,\"Lng\":%.6f,\"Position_valid\":true,",
+                    mm->decoded_lat, mm->decoded_lon);
+    else
+        p += sprintf(p, "\"Lat\":null,\"Lng\":null,\"Position_valid\":false,");
+
+    //// vrate
+    if (Modes.use_gnss) {
+        if (mm->geom_rate_valid)
+            p += sprintf(p, "\"Vvel\":%d,", mm->geom_rate);
+        else if (mm->baro_rate_valid)
+            p += sprintf(p, "\"Vvel\":%d,", mm->baro_rate);
+        else
+            p += sprintf(p,  "\"Vvel\":null,");
+    } else {
+        if (mm->baro_rate_valid)
+            p += sprintf(p, "\"Vvel\":%d,", mm->baro_rate);
+        else if (mm->geom_rate_valid)
+            p += sprintf(p, "\"Vvel\":%d,", mm->geom_rate);
+        else
+            p += sprintf(p,  "\"Vvel\":null,");
+    }
+
+    //// squawk
+    if (mm->squawk_valid)
+        p += sprintf(p, "\"Squawk\":%x,", mm->squawk);
+    else
+        p += sprintf(p, "\"Squawk\":null,");
+
+    // TODO: squawk changing alert support in stratux?
+    // TODO: squawk emergency flag?
+    // TODO: squawk ident flag?
+
+    // airground
+    switch (mm->airground) {
+        case AG_GROUND:
+            p += sprintf(p, "\"OnGround\":true,");
+            break;
+        case AG_AIRBORNE:
+            p += sprintf(p, "\"OnGround\":false,");
+            break;
+        default:
+            p += sprintf(p, "\"OnGround\":null,");
+    }
+
+    // navigation accuracy category - position
+    if (mm->accuracy.nac_p_valid) {
+        p += sprintf(p, "\"NACp\":%d,", mm->accuracy.nac_p);
+    } else {
+        p += sprintf(p, "\"NACp\":null,");
+    }
+
+    // emitter type
+    int emitter = 0;
+    int setEmitter = 0;
+    if ((mm->msgtype ==  17) || (mm->msgtype == 18)) {
+        switch (mm->metype) {
+            case 1:
+                emitter = ((mm->mesub) | 0x18);
+                setEmitter = 1;
+                break;
+            case 2:
+                emitter = ((mm->mesub) | 0x10);
+                setEmitter = 1;
+                break;
+            case 3:
+                emitter = ((mm->mesub) | 0x08);
+                setEmitter = 1;
+                break;
+            case 4:
+                emitter = (mm->mesub);
+                setEmitter = 1;
+                break;
+        }
+    }
+
+    if (setEmitter)
+        p += sprintf(p, "\"Emitter_category\":%d,", emitter);
+    else
+        p += sprintf(p, "\"Emitter_category\":null,");
+
     p += sprintf(p, "}\r\n");
 
     completeWrite(&Modes.stratux_out, p);

From eb1d42e47a6d4814e7d1fd0ca0d69ff009dc67a1 Mon Sep 17 00:00:00 2001
From: Determinant <tederminant@gmail.com>
Date: Sat, 28 Mar 2020 15:27:22 -0400
Subject: [PATCH 04/14] ...

---
 dump1090.h | 2 +-
 net_io.c   | 6 +++++-
 2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/dump1090.h b/dump1090.h
index ec45d8e..e5137ba 100644
--- a/dump1090.h
+++ b/dump1090.h
@@ -52,7 +52,7 @@
 
 // Default version number, if not overriden by the Makefile
 #ifndef MODES_DUMP1090_VERSION
-# define MODES_DUMP1090_VERSION     "v1.13-stratux"
+# define MODES_DUMP1090_VERSION     "v1.13-custom"
 #endif
 
 #ifndef MODES_DUMP1090_VARIANT
diff --git a/net_io.c b/net_io.c
index d4ca0ff..d4b3738 100644
--- a/net_io.c
+++ b/net_io.c
@@ -884,7 +884,11 @@ static void modesSendStratuxOutput(struct modesMessage *mm, struct aircraft *a)
     localtime_r(&received, &stTime_receive);
 
     // Time message received (based on system clock). Format is 2016-02-20T06:35:43.155Z
-    p += sprintf(p, "\"Timestamp\":\"%04d-%02d-%02dT%02d:%02d:%02d.%03dZ\"", (stTime_receive.tm_year+1900),(stTime_receive.tm_mon+1), stTime_receive.tm_mday, stTime_receive.tm_hour, stTime_receive.tm_min, stTime_receive.tm_sec, (unsigned) (mm->sysTimestampMsg % 1000));
+    p += sprintf(p, "\"Timestamp\":\"%04d-%02d-%02dT%02d:%02d:%02d.%03dZ\"",
+            (stTime_receive.tm_year+1900),(stTime_receive.tm_mon+1),
+            stTime_receive.tm_mday, stTime_receive.tm_hour,
+            stTime_receive.tm_min, stTime_receive.tm_sec,
+            (unsigned)(mm->sysTimestampMsg % 1000));
 
     //// callsign
     if (mm->callsign_valid)

From 8ba24e8c3bb137e38f2ce945e3f60a18d1c895a4 Mon Sep 17 00:00:00 2001
From: Determinant <tederminant@gmail.com>
Date: Sat, 28 Mar 2020 22:51:31 -0400
Subject: [PATCH 05/14] put the timestamp at last

---
 net_io.c | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/net_io.c b/net_io.c
index d4b3738..3c5f2ca 100644
--- a/net_io.c
+++ b/net_io.c
@@ -883,13 +883,6 @@ static void modesSendStratuxOutput(struct modesMessage *mm, struct aircraft *a)
     time_t received = (time_t) (mm->sysTimestampMsg / 1000);
     localtime_r(&received, &stTime_receive);
 
-    // Time message received (based on system clock). Format is 2016-02-20T06:35:43.155Z
-    p += sprintf(p, "\"Timestamp\":\"%04d-%02d-%02dT%02d:%02d:%02d.%03dZ\"",
-            (stTime_receive.tm_year+1900),(stTime_receive.tm_mon+1),
-            stTime_receive.tm_mday, stTime_receive.tm_hour,
-            stTime_receive.tm_min, stTime_receive.tm_sec,
-            (unsigned)(mm->sysTimestampMsg % 1000));
-
     //// callsign
     if (mm->callsign_valid)
         p += sprintf(p, "\"Tail\":\"%s\",", mm->callsign);
@@ -1013,6 +1006,13 @@ static void modesSendStratuxOutput(struct modesMessage *mm, struct aircraft *a)
     else
         p += sprintf(p, "\"Emitter_category\":null,");
 
+    // Time message received (based on system clock). Format is 2016-02-20T06:35:43.155Z
+    p += sprintf(p, "\"Timestamp\":\"%04d-%02d-%02dT%02d:%02d:%02d.%03dZ\"",
+            (stTime_receive.tm_year+1900),(stTime_receive.tm_mon+1),
+            stTime_receive.tm_mday, stTime_receive.tm_hour,
+            stTime_receive.tm_min, stTime_receive.tm_sec,
+            (unsigned)(mm->sysTimestampMsg % 1000));
+
     p += sprintf(p, "}\r\n");
 
     completeWrite(&Modes.stratux_out, p);

From 258e3f9d6542d65b6411ee923e1631852a7c09a6 Mon Sep 17 00:00:00 2001
From: Determinant <tederminant@gmail.com>
Date: Mon, 30 Mar 2020 12:34:11 -0400
Subject: [PATCH 06/14] turn off stratux support by default

---
 dump1090.c | 5 +++--
 net_io.c   | 9 ++++++---
 2 files changed, 9 insertions(+), 5 deletions(-)

diff --git a/dump1090.c b/dump1090.c
index 356c1f5..467676b 100644
--- a/dump1090.c
+++ b/dump1090.c
@@ -116,7 +116,7 @@ void modesInitConfig(void) {
     Modes.net_output_sbs_ports    = strdup("30003");
     Modes.net_input_beast_ports   = strdup("30004,30104");
     Modes.net_output_beast_ports  = strdup("30005");
-    Modes.net_output_stratux_ports= strdup("30006");
+    Modes.net_output_stratux_ports= NULL;
     Modes.interactive_display_ttl = MODES_INTERACTIVE_DISPLAY_TTL;
     Modes.json_interval           = 1000;
     Modes.json_location_accuracy  = 1;
@@ -535,7 +535,8 @@ int main(int argc, char **argv) {
             free(Modes.net_output_sbs_ports);
             Modes.net_output_sbs_ports = strdup(argv[++j]);
         } else if (!strcmp(argv[j],"--net-stratux-port") && more) {
-            free(Modes.net_output_stratux_ports);
+            if (Modes.net_output_stratux_ports)
+                free(Modes.net_output_stratux_ports);
             Modes.net_output_stratux_ports = strdup(argv[++j]);
         } else if (!strcmp(argv[j],"--net-buffer") && more) {
             Modes.net_sndbuf_size = atoi(argv[++j]);
diff --git a/net_io.c b/net_io.c
index 3c5f2ca..408b6b6 100644
--- a/net_io.c
+++ b/net_io.c
@@ -269,8 +269,10 @@ void modesInitNet(void) {
     s = serviceInit("Basestation TCP output", &Modes.sbs_out, send_sbs_heartbeat, READ_MODE_IGNORE, NULL, NULL);
     serviceListen(s, Modes.net_bind_address, Modes.net_output_sbs_ports);
 
-    s = serviceInit("Stratux TCP output", &Modes.stratux_out, send_stratux_heartbeat, READ_MODE_IGNORE, NULL, NULL);
-    serviceListen(s, Modes.net_bind_address, Modes.net_output_stratux_ports);
+    if (Modes.net_output_stratux_ports) {
+        s = serviceInit("Stratux TCP output", &Modes.stratux_out, send_stratux_heartbeat, READ_MODE_IGNORE, NULL, NULL);
+        serviceListen(s, Modes.net_bind_address, Modes.net_output_stratux_ports);
+    }
 
     s = serviceInit("Raw TCP input", NULL, NULL, READ_MODE_ASCII, "\n", decodeHexMessage);
     serviceListen(s, Modes.net_bind_address, Modes.net_input_raw_ports);
@@ -1042,7 +1044,8 @@ void modesQueueOutput(struct modesMessage *mm, struct aircraft *a) {
 
     // Delegate to the format-specific outputs, each of which makes its own decision about filtering messages
     modesSendSBSOutput(mm, a);
-    modesSendStratuxOutput(mm, a);
+    if (Modes.net_output_stratux_ports)
+        modesSendStratuxOutput(mm, a);
     modesSendRawOutput(mm, a);
     modesSendBeastVerbatimOutput(mm, a);
     modesSendBeastCookedOutput(mm, a);

From d25103361a3c1a6f9bafc089e3bcd51d4637ca6a Mon Sep 17 00:00:00 2001
From: Determinant <tederminant@gmail.com>
Date: Sun, 30 Aug 2020 21:21:49 -0400
Subject: [PATCH 07/14] make change according to the suggestions

---
 dump1090.c |  2 +-
 net_io.c   | 83 +++++++++++++-----------------------------------------
 2 files changed, 20 insertions(+), 65 deletions(-)

diff --git a/dump1090.c b/dump1090.c
index 467676b..f6c0dc6 100644
--- a/dump1090.c
+++ b/dump1090.c
@@ -300,7 +300,7 @@ void showHelp(void) {
 "--net-sbs-port <ports>   TCP BaseStation output listen ports (default: 30003)\n"
 "--net-bi-port <ports>    TCP Beast input listen ports  (default: 30004,30104)\n"
 "--net-bo-port <ports>    TCP Beast output listen ports (default: 30005)\n"
-"--net-stratux-port <ports>   TCP Stratux output listen ports (default: 30006)\n"
+"--net-stratux-port <ports>   TCP Stratux output listen ports (default: disabled)\n"
 "--net-ro-size <size>     TCP output minimum size (default: 0)\n"
 "--net-ro-interval <rate> TCP output memory flush rate in seconds (default: 0)\n"
 "--net-heartbeat <rate>   TCP heartbeat rate in seconds (default: 60 sec; 0 to disable)\n"
diff --git a/net_io.c b/net_io.c
index 408b6b6..25a21de 100644
--- a/net_io.c
+++ b/net_io.c
@@ -791,21 +791,20 @@ static void modesSendStratuxOutput(struct modesMessage *mm, struct aircraft *a)
     char *p;
     struct timespec now;
     struct tm    stTime_receive, stTime_now;
-    int          msgType;
 
-    // We require a tracked aircraft for SBS output
+    // We require a tracked aircraft for Stratux output
     if (!a)
         return;
 
-    // Don't ever forward 2-bit-corrected messages via SBS output.
+    // Don't ever forward 2-bit-corrected messages via Stratux output.
     if (mm->correctedbits >= 2)
         return;
 
-    // Don't ever forward mlat messages via SBS output.
+    // Don't ever forward mlat messages via Stratux output.
     if (mm->source == SOURCE_MLAT)
         return;
 
-    // Don't ever send unreliable messages via SBS output
+    // Don't ever send unreliable messages via Stratux output
     if (!mm->reliable && !a->reliable)
         return;
 
@@ -817,42 +816,6 @@ static void modesSendStratuxOutput(struct modesMessage *mm, struct aircraft *a)
     if (!p)
         return;
 
-    // NOTE: not sure about message types, so keep the original code from
-    // stratux/dump1090 as-is.
-    //
-    // Decide on the basic SBS Message Type
-    if        ((mm->msgtype ==  4) || (mm->msgtype == 20)) {
-        msgType = 5;
-    } else if ((mm->msgtype ==  5) || (mm->msgtype == 21)) {
-        msgType = 6;
-    } else if ((mm->msgtype ==  0) || (mm->msgtype == 16)) {
-        msgType = 7;
-    } else if  (mm->msgtype == 11) {
-        msgType = 8;
-    } else if ((mm->msgtype != 17) && (mm->msgtype != 18)) {
-        return;
-    } else if ((mm->metype >= 1) && (mm->metype <=  4)) {
-        msgType = 1;
-    } else if ((mm->metype >= 5) && (mm->metype <=  8)) {
-        if (mm->cpr_decoded)
-            {msgType = 2;}
-        else
-            {msgType = 7;}
-    } else if ((mm->metype >= 9) && (mm->metype <= 18)) {
-        if (mm->cpr_decoded)
-            {msgType = 3;}
-        else
-            {msgType = 7;}
-    } else if ((mm->metype == 29) || (mm->metype == 31)) {
-        msgType = 9; // new message type for target state and operational status messages
-    } else if (mm->metype !=  19) {
-        return;
-    } else if ((mm->mesub == 1) || (mm->mesub == 2)) {
-        msgType = 4;
-    } else {
-        return;
-    }
-
     // Begin populating the traffic.go fields.
     // ICAO address, Mode S message types, and signal level
 
@@ -868,13 +831,11 @@ static void modesSendStratuxOutput(struct modesMessage *mm, struct aircraft *a)
             "\"DF\":%d,\"CA\":%d,"
             "\"TypeCode\":%d,"
             "\"SubtypeCode\":%d,"
-            "\"SBS_MsgType\":%d,"
             "\"SignalLevel\":%f,",
             mm->addr,
             mm->msgtype, cacf,
             mm->metype,
             mm->mesub,
-            msgType,
             mm->signalLevel); // what precision and range is needed for RSSI?
 
     // Find current system time
@@ -892,14 +853,17 @@ static void modesSendStratuxOutput(struct modesMessage *mm, struct aircraft *a)
         p += sprintf(p, "\"Tail\":null,");
 
     //// altitude & gnss
-    bool alt_is_geom = false;
-    if (Modes.use_gnss && mm->altitude_geom_valid) {
+    bool alt_is_geom;
+    if (mm->altitude_baro_valid) {
+        p += sprintf(p, "\"Alt\":%d,",mm->altitude_baro);
+        alt_is_geom = false;
+    } else if (mm->altitude_geom_valid) {
         p += sprintf(p, "\"Alt\":%d,",mm->altitude_geom);
         alt_is_geom = true;
-    } else if (mm->altitude_baro_valid)
-        p += sprintf(p, "\"Alt\":%d,",mm->altitude_baro);
-    else
+    } else {
         p += sprintf(p, "\"Alt\":null,");
+        alt_is_geom = false;
+    }
 
     // altitude source
     if (alt_is_geom)
@@ -933,22 +897,13 @@ static void modesSendStratuxOutput(struct modesMessage *mm, struct aircraft *a)
     else
         p += sprintf(p, "\"Lat\":null,\"Lng\":null,\"Position_valid\":false,");
 
-    //// vrate
-    if (Modes.use_gnss) {
-        if (mm->geom_rate_valid)
-            p += sprintf(p, "\"Vvel\":%d,", mm->geom_rate);
-        else if (mm->baro_rate_valid)
-            p += sprintf(p, "\"Vvel\":%d,", mm->baro_rate);
-        else
-            p += sprintf(p,  "\"Vvel\":null,");
-    } else {
-        if (mm->baro_rate_valid)
-            p += sprintf(p, "\"Vvel\":%d,", mm->baro_rate);
-        else if (mm->geom_rate_valid)
-            p += sprintf(p, "\"Vvel\":%d,", mm->geom_rate);
-        else
-            p += sprintf(p,  "\"Vvel\":null,");
-    }
+    //// vrate (use barometric if possible)
+    if (mm->baro_rate_valid)
+        p += sprintf(p, "\"Vvel\":%d,", mm->baro_rate);
+    else if (mm->geom_rate_valid)
+        p += sprintf(p, "\"Vvel\":%d,", mm->geom_rate);
+    else
+        p += sprintf(p,  "\"Vvel\":null,");
 
     //// squawk
     if (mm->squawk_valid)

From c89930b4b94834d549b9b5ddc00fefcf603c859c Mon Sep 17 00:00:00 2001
From: Determinant <tederminant@gmail.com>
Date: Mon, 7 Sep 2020 15:36:34 -0400
Subject: [PATCH 08/14] forward mlat messages to Stratux

---
 net_io.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/net_io.c b/net_io.c
index 25a21de..225dac6 100644
--- a/net_io.c
+++ b/net_io.c
@@ -800,9 +800,7 @@ static void modesSendStratuxOutput(struct modesMessage *mm, struct aircraft *a)
     if (mm->correctedbits >= 2)
         return;
 
-    // Don't ever forward mlat messages via Stratux output.
-    if (mm->source == SOURCE_MLAT)
-        return;
+    // NOTE: mlat messages are forwarded via Stratux output.
 
     // Don't ever send unreliable messages via Stratux output
     if (!mm->reliable && !a->reliable)

From bc9336e0be00f30568774ae025833b2f23c1245e Mon Sep 17 00:00:00 2001
From: Oliver Jowett <oliver.jowett@flightaware.com>
Date: Tue, 8 Sep 2020 23:10:18 +0800
Subject: [PATCH 09/14] Revert "forward mlat messages to Stratux"

This reverts commit c89930b4b94834d549b9b5ddc00fefcf603c859c.
---
 net_io.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/net_io.c b/net_io.c
index 7b7876b..c65a43c 100644
--- a/net_io.c
+++ b/net_io.c
@@ -800,7 +800,9 @@ static void modesSendStratuxOutput(struct modesMessage *mm, struct aircraft *a)
     if (mm->correctedbits >= 2)
         return;
 
-    // NOTE: mlat messages are forwarded via Stratux output.
+    // Don't ever forward mlat messages via Stratux output.
+    if (mm->source == SOURCE_MLAT)
+        return;
 
     // Don't ever send unreliable messages via Stratux output
     if (!mm->reliable && !a->reliable)

From ec90edcd8db077ead144be3a39455735dd4d9229 Mon Sep 17 00:00:00 2001
From: Oliver Jowett <oliver.jowett@flightaware.com>
Date: Tue, 8 Sep 2020 23:21:34 +0800
Subject: [PATCH 10/14] Simpify stratux service init

---
 net_io.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/net_io.c b/net_io.c
index c65a43c..14bceda 100644
--- a/net_io.c
+++ b/net_io.c
@@ -269,10 +269,8 @@ void modesInitNet(void) {
     s = serviceInit("Basestation TCP output", &Modes.sbs_out, send_sbs_heartbeat, READ_MODE_IGNORE, NULL, NULL);
     serviceListen(s, Modes.net_bind_address, Modes.net_output_sbs_ports);
 
-    if (Modes.net_output_stratux_ports) {
-        s = serviceInit("Stratux TCP output", &Modes.stratux_out, send_stratux_heartbeat, READ_MODE_IGNORE, NULL, NULL);
-        serviceListen(s, Modes.net_bind_address, Modes.net_output_stratux_ports);
-    }
+    s = serviceInit("Stratux TCP output", &Modes.stratux_out, send_stratux_heartbeat, READ_MODE_IGNORE, NULL, NULL);
+    serviceListen(s, Modes.net_bind_address, Modes.net_output_stratux_ports);
 
     s = serviceInit("Raw TCP input", NULL, NULL, READ_MODE_ASCII, "\n", decodeHexMessage);
     serviceListen(s, Modes.net_bind_address, Modes.net_input_raw_ports);

From da3e9766dec303bb604b6d092932266719c82cd0 Mon Sep 17 00:00:00 2001
From: Oliver Jowett <oliver.jowett@flightaware.com>
Date: Tue, 8 Sep 2020 23:22:53 +0800
Subject: [PATCH 11/14] Harden the stratux output a bit: use safe_snprintf,
 jsonEscapeString

---
 net_io.c | 89 +++++++++++++++++++++++++++++---------------------------
 1 file changed, 46 insertions(+), 43 deletions(-)

diff --git a/net_io.c b/net_io.c
index 14bceda..3740301 100644
--- a/net_io.c
+++ b/net_io.c
@@ -86,6 +86,11 @@ static void writeFATSVPositionUpdate(float lat, float lon, float alt);
 
 static void autoset_modeac();
 
+__attribute__ ((format (printf,3,0))) static char *safe_vsnprintf(char *p, char *end, const char *format, va_list ap);
+__attribute__ ((format (printf,3,4))) static char *safe_snprintf(char *p, char *end, const char *format, ...);
+
+static const char *jsonEscapeString(const char *str);
+
 //
 //=========================================================================
 //
@@ -785,6 +790,8 @@ static void send_sbs_heartbeat(struct net_service *service)
 //
 // Write Stratux output to TCP clients
 //
+
+#define STRATUX_MAX_PACKET_SIZE 1000
 static void modesSendStratuxOutput(struct modesMessage *mm, struct aircraft *a) {
     char *p;
     struct timespec now;
@@ -806,14 +813,12 @@ static void modesSendStratuxOutput(struct modesMessage *mm, struct aircraft *a)
     if (!mm->reliable && !a->reliable)
         return;
 
-    //// For now, suppress non-ICAO addresses
-    //if (mm->addr & MODES_NON_ICAO_ADDRESS)
-    //    return;
-
-    p = prepareWrite(&Modes.stratux_out, 1000); // larger buffer size needed vs SBS
+    p = prepareWrite(&Modes.stratux_out, STRATUX_MAX_PACKET_SIZE); // larger buffer size needed vs SBS
     if (!p)
         return;
 
+    char *end = p + STRATUX_MAX_PACKET_SIZE;
+
     // Begin populating the traffic.go fields.
     // ICAO address, Mode S message types, and signal level
 
@@ -824,7 +829,7 @@ static void modesSendStratuxOutput(struct modesMessage *mm, struct aircraft *a)
         cacf = mm->CF;
     }
 
-    p += sprintf(p,
+    p = safe_snprintf(p, end,
             "{\"Icao_addr\":%d,"
             "\"DF\":%d,\"CA\":%d,"
             "\"TypeCode\":%d,"
@@ -846,68 +851,68 @@ static void modesSendStratuxOutput(struct modesMessage *mm, struct aircraft *a)
 
     //// callsign
     if (mm->callsign_valid)
-        p += sprintf(p, "\"Tail\":\"%s\",", mm->callsign);
+        p = safe_snprintf(p, end, "\"Tail\":\"%s\",", jsonEscapeString(mm->callsign));
     else
-        p += sprintf(p, "\"Tail\":null,");
+        p = safe_snprintf(p, end, "\"Tail\":null,");
 
     //// altitude & gnss
     bool alt_is_geom;
     if (mm->altitude_baro_valid) {
-        p += sprintf(p, "\"Alt\":%d,",mm->altitude_baro);
+        p = safe_snprintf(p, end, "\"Alt\":%d,",mm->altitude_baro);
         alt_is_geom = false;
     } else if (mm->altitude_geom_valid) {
-        p += sprintf(p, "\"Alt\":%d,",mm->altitude_geom);
+        p = safe_snprintf(p, end, "\"Alt\":%d,",mm->altitude_geom);
         alt_is_geom = true;
     } else {
-        p += sprintf(p, "\"Alt\":null,");
+        p = safe_snprintf(p, end, "\"Alt\":null,");
         alt_is_geom = false;
     }
 
     // altitude source
     if (alt_is_geom)
-        p += sprintf(p, "\"AltIsGNSS\":true,");
+        p = safe_snprintf(p, end, "\"AltIsGNSS\":true,");
     else
-        p += sprintf(p, "\"AltIsGNSS\":false,");
+        p = safe_snprintf(p, end, "\"AltIsGNSS\":false,");
 
     // GNSS alt. delta From baro alt.
     if (trackDataValid(&a->geom_delta_valid))
-        p += sprintf(p, "\"GnssDiffFromBaroAlt\":%d,",a->geom_delta);
+        p = safe_snprintf(p, end, "\"GnssDiffFromBaroAlt\":%d,",a->geom_delta);
     else
-        p += sprintf(p, "\"GnssDiffFromBaroAlt\":null,");
+        p = safe_snprintf(p, end, "\"GnssDiffFromBaroAlt\":null,");
     ////
 
     //// ground speed and track
     if (mm->gs_valid)
-        p += sprintf(p, "\"Speed_valid\":true,\"Speed\":%.0f,", mm->gs.selected);
+        p = safe_snprintf(p, end, "\"Speed_valid\":true,\"Speed\":%.0f,", mm->gs.selected);
     else
-        p += sprintf(p, "\"Speed_valid\":false,\"Speed\":null,");
+        p = safe_snprintf(p, end, "\"Speed_valid\":false,\"Speed\":null,");
 
     //// ground heading
     if (mm->heading_valid && mm->heading_type == HEADING_GROUND_TRACK)
-        p += sprintf(p, "\"Track\":%.0f,", mm->heading);
+        p = safe_snprintf(p, end, "\"Track\":%.0f,", mm->heading);
     else
-        p += sprintf(p, "\"Track\":null,");
+        p = safe_snprintf(p, end, "\"Track\":null,");
 
     //// position
     if (mm->cpr_decoded)
-        p += sprintf(p, "\"Lat\":%.6f,\"Lng\":%.6f,\"Position_valid\":true,",
+        p = safe_snprintf(p, end, "\"Lat\":%.6f,\"Lng\":%.6f,\"Position_valid\":true,",
                     mm->decoded_lat, mm->decoded_lon);
     else
-        p += sprintf(p, "\"Lat\":null,\"Lng\":null,\"Position_valid\":false,");
+        p = safe_snprintf(p, end, "\"Lat\":null,\"Lng\":null,\"Position_valid\":false,");
 
     //// vrate (use barometric if possible)
     if (mm->baro_rate_valid)
-        p += sprintf(p, "\"Vvel\":%d,", mm->baro_rate);
+        p = safe_snprintf(p, end, "\"Vvel\":%d,", mm->baro_rate);
     else if (mm->geom_rate_valid)
-        p += sprintf(p, "\"Vvel\":%d,", mm->geom_rate);
+        p = safe_snprintf(p, end, "\"Vvel\":%d,", mm->geom_rate);
     else
-        p += sprintf(p,  "\"Vvel\":null,");
+        p = safe_snprintf(p, end, "\"Vvel\":null,");
 
     //// squawk
     if (mm->squawk_valid)
-        p += sprintf(p, "\"Squawk\":%x,", mm->squawk);
+        p = safe_snprintf(p, end, "\"Squawk\":%x,", mm->squawk);
     else
-        p += sprintf(p, "\"Squawk\":null,");
+        p = safe_snprintf(p, end, "\"Squawk\":null,");
 
     // TODO: squawk changing alert support in stratux?
     // TODO: squawk emergency flag?
@@ -916,61 +921,59 @@ static void modesSendStratuxOutput(struct modesMessage *mm, struct aircraft *a)
     // airground
     switch (mm->airground) {
         case AG_GROUND:
-            p += sprintf(p, "\"OnGround\":true,");
+            p = safe_snprintf(p, end, "\"OnGround\":true,");
             break;
         case AG_AIRBORNE:
-            p += sprintf(p, "\"OnGround\":false,");
+            p = safe_snprintf(p, end, "\"OnGround\":false,");
             break;
         default:
-            p += sprintf(p, "\"OnGround\":null,");
+            p = safe_snprintf(p, end, "\"OnGround\":null,");
     }
 
     // navigation accuracy category - position
     if (mm->accuracy.nac_p_valid) {
-        p += sprintf(p, "\"NACp\":%d,", mm->accuracy.nac_p);
+        p = safe_snprintf(p, end, "\"NACp\":%d,", mm->accuracy.nac_p);
     } else {
-        p += sprintf(p, "\"NACp\":null,");
+        p = safe_snprintf(p, end, "\"NACp\":null,");
     }
 
     // emitter type
-    int emitter = 0;
-    int setEmitter = 0;
+    int emitter = -1;
     if ((mm->msgtype ==  17) || (mm->msgtype == 18)) {
         switch (mm->metype) {
             case 1:
                 emitter = ((mm->mesub) | 0x18);
-                setEmitter = 1;
                 break;
             case 2:
                 emitter = ((mm->mesub) | 0x10);
-                setEmitter = 1;
                 break;
             case 3:
                 emitter = ((mm->mesub) | 0x08);
-                setEmitter = 1;
                 break;
             case 4:
                 emitter = (mm->mesub);
-                setEmitter = 1;
                 break;
         }
     }
 
-    if (setEmitter)
-        p += sprintf(p, "\"Emitter_category\":%d,", emitter);
+    if (emitter >= 0)
+        p = safe_snprintf(p, end, "\"Emitter_category\":%d,", emitter);
     else
-        p += sprintf(p, "\"Emitter_category\":null,");
+        p = safe_snprintf(p, end, "\"Emitter_category\":null,");
 
     // Time message received (based on system clock). Format is 2016-02-20T06:35:43.155Z
-    p += sprintf(p, "\"Timestamp\":\"%04d-%02d-%02dT%02d:%02d:%02d.%03dZ\"",
+    p = safe_snprintf(p, end, "\"Timestamp\":\"%04d-%02d-%02dT%02d:%02d:%02d.%03dZ\"",
             (stTime_receive.tm_year+1900),(stTime_receive.tm_mon+1),
             stTime_receive.tm_mday, stTime_receive.tm_hour,
             stTime_receive.tm_min, stTime_receive.tm_sec,
             (unsigned)(mm->sysTimestampMsg % 1000));
 
-    p += sprintf(p, "}\r\n");
+    p = safe_snprintf(p, end, "}\r\n");
 
-    completeWrite(&Modes.stratux_out, p);
+    if (p < end)
+        completeWrite(&Modes.stratux_out, p);
+    else
+        fprintf(stderr, "stratux: output too large (max %d, overran by %d)\n", STRATUX_MAX_PACKET_SIZE, (int) (p - end));
 }
 
 static void send_stratux_heartbeat(struct net_service *service)

From 9b06099971a6d7acd0b1270a0d5ac6372b4777c4 Mon Sep 17 00:00:00 2001
From: Oliver Jowett <oliver.jowett@flightaware.com>
Date: Tue, 8 Sep 2020 23:25:01 +0800
Subject: [PATCH 12/14] Enable net mode on bare stratux port option

---
 dump1090.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/dump1090.c b/dump1090.c
index c8304a2..aa23b73 100644
--- a/dump1090.c
+++ b/dump1090.c
@@ -550,6 +550,7 @@ int main(int argc, char **argv) {
             free(Modes.net_output_sbs_ports);
             Modes.net_output_sbs_ports = strdup(argv[++j]);
         } else if (!strcmp(argv[j],"--net-stratux-port") && more) {
+            Modes.net = 1;
             free(Modes.net_output_stratux_ports);
             Modes.net_output_stratux_ports = strdup(argv[++j]);
         } else if (!strcmp(argv[j],"--net-buffer") && more) {

From 7356676c5b2ef2db2b147d223ee4db5dafe414e4 Mon Sep 17 00:00:00 2001
From: Oliver Jowett <oliver.jowett@flightaware.com>
Date: Tue, 8 Sep 2020 23:30:24 +0800
Subject: [PATCH 13/14] Don't need conditional output on the stratux port,
 that's done in prepareWrite()

---
 net_io.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/net_io.c b/net_io.c
index 3740301..64436b7 100644
--- a/net_io.c
+++ b/net_io.c
@@ -1000,8 +1000,7 @@ void modesQueueOutput(struct modesMessage *mm, struct aircraft *a) {
 
     // Delegate to the format-specific outputs, each of which makes its own decision about filtering messages
     modesSendSBSOutput(mm, a);
-    if (Modes.net_output_stratux_ports)
-        modesSendStratuxOutput(mm, a);
+    modesSendStratuxOutput(mm, a);
     modesSendRawOutput(mm, a);
     modesSendBeastVerbatimOutput(mm, a);
     modesSendBeastCookedOutput(mm, a);

From 303dcc991575bfadf85e0e2858cc64b1c0271a5d Mon Sep 17 00:00:00 2001
From: Oliver Jowett <oliver.jowett@flightaware.com>
Date: Tue, 8 Sep 2020 23:35:17 +0800
Subject: [PATCH 14/14] Fix stratux output timestamps to really be UTC as they
 claim

---
 net_io.c | 13 +++----------
 1 file changed, 3 insertions(+), 10 deletions(-)

diff --git a/net_io.c b/net_io.c
index 64436b7..f0754c4 100644
--- a/net_io.c
+++ b/net_io.c
@@ -794,8 +794,6 @@ static void send_sbs_heartbeat(struct net_service *service)
 #define STRATUX_MAX_PACKET_SIZE 1000
 static void modesSendStratuxOutput(struct modesMessage *mm, struct aircraft *a) {
     char *p;
-    struct timespec now;
-    struct tm    stTime_receive, stTime_now;
 
     // We require a tracked aircraft for Stratux output
     if (!a)
@@ -841,14 +839,6 @@ static void modesSendStratuxOutput(struct modesMessage *mm, struct aircraft *a)
             mm->mesub,
             mm->signalLevel); // what precision and range is needed for RSSI?
 
-    // Find current system time
-    clock_gettime(CLOCK_REALTIME, &now);
-    gmtime_r(&now.tv_sec, &stTime_now);  // we expect UTC
-
-    // Find message reception time
-    time_t received = (time_t) (mm->sysTimestampMsg / 1000);
-    localtime_r(&received, &stTime_receive);
-
     //// callsign
     if (mm->callsign_valid)
         p = safe_snprintf(p, end, "\"Tail\":\"%s\",", jsonEscapeString(mm->callsign));
@@ -962,6 +952,9 @@ static void modesSendStratuxOutput(struct modesMessage *mm, struct aircraft *a)
         p = safe_snprintf(p, end, "\"Emitter_category\":null,");
 
     // Time message received (based on system clock). Format is 2016-02-20T06:35:43.155Z
+    struct tm stTime_receive;
+    time_t received = (time_t) (mm->sysTimestampMsg / 1000);
+    gmtime_r(&received, &stTime_receive);
     p = safe_snprintf(p, end, "\"Timestamp\":\"%04d-%02d-%02dT%02d:%02d:%02d.%03dZ\"",
             (stTime_receive.tm_year+1900),(stTime_receive.tm_mon+1),
             stTime_receive.tm_mday, stTime_receive.tm_hour,