AX-688 - Gate UAV/drone support behind --enable-uav runtime flag

Author: awhite-jetnet

help.h

@@ -59,6 +59,7 @@ static struct argp_option optionsReadsb[] = {
     {"interactive-ttl", OptInteractiveTTL, "<sec>", 0, "Remove from list if idle for <sec> (default: 60)", 1},
     {"modeac", OptModeAc, 0, 0, "Enable decoding of SSR Modes 3/A & 3/C", 1},
     {"modeac-auto", OptModeAcAuto, 0, 0, "Enable Mode A/C if requested by a Beast connection", 1},
+    {"enable-uav", OptEnableUav, 0, 0, "Enable processing of UAV/drone data ($ prefix in SBS input)", 1},
     {"max-range", OptMaxRange, "<dist>", 0, "Absolute maximum range for position decoding (in nm, default: 300)", 1},
     {"fix", OptFix, 0, 0, "Enable CRC single-bit error correction (default)", 1},
     {"no-fix", OptNoFix, 0, 0, "Disable CRC single-bit error correction", 1},

net_io.c

@@ -2994,7 +2994,7 @@ static int decodeSbsLine(struct client *c, char *line, int remote, int64_t now,
     char *icao = t[5];
 
     // Check for $ prefix (UAV/drone identifier)
-    if (icao_len == 7 && icao[0] == '$') {
+    if (Modes.enable_uav && icao_len == 7 && icao[0] == '$') {
         is_uav = 1;
         icao = t[5] + 1;  // Skip $ prefix
         icao_len = 6;

readsb.c

@@ -1481,6 +1481,9 @@ static error_t parse_opt(int key, char *arg, struct argp_state *state) {
         case OptModeAcAuto:
             Modes.mode_ac_auto = 1;
             break;
+        case OptEnableUav:
+            Modes.enable_uav = 1;
+            break;
         case OptNetOnly:
             Modes.net = 1;
             Modes.net_only = 1;

readsb.h

@@ -640,6 +640,7 @@ struct _Modes
     int8_t raw; // Raw output format
     int8_t mode_ac; // Enable decoding of SSR Modes A & C
     int8_t mode_ac_auto; // allow toggling of A/C by Beast commands
+    int8_t enable_uav; // Enable processing of UAV/drone data
     int8_t debug_net;
     int8_t debug_flush;
     int8_t debug_no_discard;
@@ -1272,6 +1273,7 @@ enum {
     OptSoapyBandwith,
     OptSoapyEnableAgc,
     OptSoapyGainElement,
+    OptEnableUav,
 };