From Jon Ellch via bug 5175:

Please see the attached patch which updates the ppi-geolocation support
to v2.0 of the specification. This iteration adds a new tag (sensor) and
removes support for velocity/acceleration from the vector tag. Most of
the changes center on the Vector tag. Everything that takes place
elsewhere is cosmetic.

I ran this iteration through fuzz-test and check-APIs just like last
time.


From me:

Replace tvb_get_ephemeral_string with tvb_format_text. Move dissector
registration to the bottom of each file.

svn path=/trunk/; revision=37733

1 files changed, 268 insertions, 250 deletions

diff --git a/epan/dissectors/packet-ppi-gps.c b/epan/dissectors/packet-ppi-gps.c
index a01fc7fb3a..829f857924 100644
--- a/epan/dissectors/packet-ppi-gps.c
+++ b/epan/dissectors/packet-ppi-gps.c
@@ -36,6 +36,7 @@
 #include <epan/prefs.h>
 #include <epan/reassemble.h>
 #include <epan/dissectors/packet-ppi-geolocation-common.h>
+
 enum ppi_geotagging_type {
     PPI_GEOTAG_GPSFLAGS = 0,
     PPI_GEOTAG_LAT = 1,
@@ -52,7 +53,24 @@ enum ppi_geotagging_type {
     PPI_GEOTAG_APPDATA = 30,
     PPI_GEOTAG_EXT = 31
 };
-#define PPI_GPS_MAXTAGLEN  148 /* This increases as fields above are added */
+#define PPI_GPS_MAXTAGLEN  144 /* increase as fields are added */
+
+#define PPI_GPS_MASK_GPSFLAGS       0x00000001
+#define PPI_GPS_MASK_LAT            0x00000002
+#define PPI_GPS_MASK_LON            0x00000004
+#define PPI_GPS_MASK_ALT            0x00000008
+#define PPI_GPS_MASK_ALT_G          0x00000010
+
+#define PPI_GPS_MASK_GPSTIME        0x00000020
+#define PPI_GPS_MASK_FRACTIME       0x00000040
+#define PPI_GPS_MASK_EPH            0x00000080
+#define PPI_GPS_MASK_EPV            0x00000100
+#define PPI_GPS_MASK_EPT            0x00000200
+
+#define PPI_GPS_MASK_DESCRSTR       0x10000000
+#define PPI_GPS_MASK_APPID          0x20000000
+#define PPI_GPS_MASK_APPDATA        0x40000000
+#define PPI_GPS_MASK_EXT            0x80000000
 
 
 /* protocol */
@@ -72,7 +90,7 @@ static int hf_ppi_gps_fractime = -1;
 static int hf_ppi_gps_eph = -1;
 static int hf_ppi_gps_epv = -1;
 static int hf_ppi_gps_ept = -1;
-static int hf_ppi_gps_descr = -1;
+static int hf_ppi_gps_descstr = -1;
 static int hf_ppi_gps_appspecific_num = -1; /* 4-byte tag no */
 static int hf_ppi_gps_appspecific_data = -1; /* 60 byte arbitrary data */
 /* "Present" flags, tese represent decoded-bits in the gui */
@@ -110,232 +128,6 @@ static gint ett_ppi_gps_gpsflags_flags= -1;
 static void
 dissect_ppi_gps(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree);
 
-void
-proto_register_ppi_gps(void) {
-    /* The following array initializes those header fields declared above to the values displayed */
-    static hf_register_info hf[] = {
-        { &hf_ppi_gps_version,
-            { "Header revision", "ppi_gps.version",
-                FT_UINT8, BASE_DEC, NULL, 0x0,
-                "Version of ppi_gps header format", HFILL } },
-        { &hf_ppi_gps_pad,
-          { "Header pad", "ppi_gps.pad",
-            FT_UINT8, BASE_DEC, NULL, 0x0,
-            "Padding", HFILL } },
-        { &hf_ppi_gps_length,
-          { "Header length", "ppi_gps.length",
-            FT_UINT16, BASE_DEC, NULL, 0x0,
-            "Length of header including version, pad, length and data fields", HFILL } },
-        { &hf_ppi_gps_present, /* these flag fields are composed of a uint32 on the display */
-          { "Present", "ppi_gps.present",
-            FT_UINT32, BASE_HEX, NULL, 0x0,
-            "Bitmask indicating which fields are present", HFILL } },
-
-#define PPI_GPS_MASK_GPSFLAGS       0x00000001
-#define PPI_GPS_MASK_LAT            0x00000002
-#define PPI_GPS_MASK_LON            0x00000004
-#define PPI_GPS_MASK_ALT            0x00000008
-#define PPI_GPS_MASK_ALT_G          0x00000010
-
-#define PPI_GPS_MASK_GPSTIME        0x00000020
-#define PPI_GPS_MASK_FRACTIME       0x00000040
-#define PPI_GPS_MASK_EPH            0x00000080
-#define PPI_GPS_MASK_EPV            0x00000100
-#define PPI_GPS_MASK_EPT            0x00000200
-
-#define PPI_GPS_MASK_DESCRSTR       0x10000000
-#define PPI_GPS_MASK_APPID          0x20000000
-#define PPI_GPS_MASK_APPDATA        0x40000000
-#define PPI_GPS_MASK_EXT            0x80000000
-
-        /* Boolean 'present' flags */
-        { &hf_ppi_gps_present_gpsflags_flags, /* followed by a lot of booleans */
-          { "GPSFlags", "ppi_gps.present.gpsflagss",
-            FT_BOOLEAN, 32, NULL, PPI_GPS_MASK_GPSFLAGS,
-            "32-bit bitmask indicating type of GPS fix (GPS/INS/software/etc)", HFILL } },
-        { &hf_ppi_gps_present_lat,
-          { "Lat", "ppi_gps.present.lat",
-            FT_BOOLEAN, 32, NULL, PPI_GPS_MASK_LAT,
-            "Specifies if the latitude field is present", HFILL } },
-
-        { &hf_ppi_gps_present_lon,
-          { "Lon", "ppi_gps.present.lon",
-            FT_BOOLEAN, 32, NULL, PPI_GPS_MASK_LON,
-            "Specifies if the longitude field is present", HFILL } },
-
-        { &hf_ppi_gps_present_alt,
-          { "Alt", "ppi_gps.present.alt",
-            FT_BOOLEAN, 32, NULL, PPI_GPS_MASK_ALT,
-            "Specifies if the altitude field is present", HFILL } },
-
-        { &hf_ppi_gps_present_alt_gnd,
-          { "Alt-gnd", "ppi_gps.present.alt_gnd",
-            FT_BOOLEAN, 32, NULL, PPI_GPS_MASK_ALT_G,
-            "Specifies if the altitude-g field is present", HFILL } },
-
-        { &hf_ppi_gps_present_gpstime,
-          { "GPStime", "ppi_gps.present.gpstime",
-            FT_BOOLEAN, 32, NULL, PPI_GPS_MASK_GPSTIME,
-            "Specifies if the GPS time field is present", HFILL } },
-
-
-        { &hf_ppi_gps_present_fractime,
-          { "fractime", "ppi_gps.present.fractime",
-            FT_BOOLEAN, 32, NULL, PPI_GPS_MASK_FRACTIME,
-            "Specifies if the fractional time field is present", HFILL } },
-
-
-        { &hf_ppi_gps_present_eph,
-          { "error_h", "ppi_gps.present.eph",
-            FT_BOOLEAN, 32, NULL, PPI_GPS_MASK_EPH,
-            "Specifies if the horizontal error field is present (eph)", HFILL } },
-
-        { &hf_ppi_gps_present_epv,
-          { "error_v", "ppi_gps.present.epv",
-            FT_BOOLEAN, 32, NULL, PPI_GPS_MASK_EPV,
-            "Specifies if the vertical error field present (epv)", HFILL } },
-
-
-        { &hf_ppi_gps_present_ept,
-          { "error_t", "ppi_gps.present.ept",
-            FT_BOOLEAN, 32, NULL, PPI_GPS_MASK_EPT,
-            "Specifies if the estimed time error field is present (ept)", HFILL } },
-
-        { &hf_ppi_gps_present_descr,
-          { "Description", "ppi_gps.present.descr",
-            FT_BOOLEAN, 32, NULL, PPI_GPS_MASK_DESCRSTR,
-            "Specifies if the (ASCII) description is present", HFILL } },
-
-        { &hf_ppi_gps_present_appspecific_num,
-          { "AppId", "ppi_gps.present.appid",
-            FT_BOOLEAN, 32, NULL, PPI_GPS_MASK_APPID,
-            "Specifies if the application specific field id is present", HFILL } },
-
-        { &hf_ppi_gps_present_appspecific_data,
-          { "AppData", "ppi_gps.present.appdata",
-            FT_BOOLEAN, 32, NULL, PPI_GPS_MASK_APPDATA,
-            "Specifies if the application specific data field  is present", HFILL } },
-
-        { &hf_ppi_gps_present_ext,
-          { "Ext", "ppi_gps.present.ext",
-            FT_BOOLEAN, 32, NULL, PPI_GPS_MASK_EXT,
-            "Specifies if there are any extensions to the header present", HFILL } },
-
-        /* ---Now we get to the actual data fields--- */
-
-        { &hf_ppi_gps_gpsflags_flags,
-          { "GPSFlags", "ppi_gps.gpsflags",
-            FT_UINT32, BASE_HEX, NULL, 0x0,
-            "Bitmask indicating GPS/INS/manual fix", HFILL } },
-        { &hf_ppi_gps_lat,
-          { "Latitude", "ppi_gps.lat",
-            FT_DOUBLE, BASE_NONE, NULL, 0x0,
-            "Latitude packet was received at", HFILL } },
-        { &hf_ppi_gps_lon,
-          { "Longitude", "ppi_gps.lon",
-            FT_DOUBLE, BASE_NONE, NULL, 0x0,
-            "Longitude packet was received at", HFILL } },
-        { &hf_ppi_gps_alt,
-          { "Altitude", "ppi_gps.alt",
-            FT_DOUBLE, BASE_NONE, NULL, 0x0,
-            "Altitude packet was received at", HFILL } },
-        { &hf_ppi_gps_alt_gnd,
-          { "Altitude_gnd", "ppi_gps.alt_gnd",
-            FT_DOUBLE, BASE_NONE, NULL, 0x0,
-            "Altitude packet was received at (relative to ground)", HFILL } },
-        { &hf_ppi_gps_gpstime,
-          { "GPSTimestamp", "ppi_gps.gpstime",
-            FT_ABSOLUTE_TIME, ABSOLUTE_TIME_UTC, NULL, 0x0,
-            "GPSTimestamp packet was received at", HFILL } },
-        { &hf_ppi_gps_fractime,
-          { "fractional Timestamp", "ppi_gps.fractime",
-            FT_DOUBLE, BASE_NONE, NULL, 0x0,
-            "fractional GPSTimestamp packet was received at", HFILL } },
-        { &hf_ppi_gps_eph,
-          { "Horizontal Error (m)", "ppi_gps.eph",
-            FT_DOUBLE, BASE_NONE, NULL, 0x0,
-            "Horizontal margin of error (meters)", HFILL } },
-        { &hf_ppi_gps_epv,
-          { "Vertical Error (m)", "ppi_gps.epv",
-            FT_DOUBLE, BASE_NONE, NULL, 0x0,
-            "Vertical margin of error (meters)", HFILL } },
-        { &hf_ppi_gps_ept,
-          { "Time Error (s)", "ppi_gps.ept",
-            FT_DOUBLE, BASE_NONE, NULL, 0x0,
-            "Time margin of error (secs)", HFILL } },
-        { &hf_ppi_gps_descr,
-          { "Description", "ppi_gps.descr",
-            FT_STRING, BASE_NONE, NULL, 0x0,
-            NULL, HFILL } },
-        { &hf_ppi_gps_appspecific_num,
-          { "Application Specific id", "ppi_gps.appid",
-            FT_UINT32, BASE_HEX, NULL, 0x0,
-            "Application-specific identifier", HFILL } },
-        { &hf_ppi_gps_appspecific_data,
-          { "Application specific data", "ppi_gps.appdata",
-            FT_BYTES, BASE_NONE, NULL, 0x0,
-            NULL, HFILL } },
-
-        /* --- moving on to the 'FixType' flags --- */
-#define PPI_GPS_GPSFLAGS_FLAG0_NOFIX     0x00000001
-#define PPI_GPS_GPSFLAGS_FLAG1_GPS       0x00000002
-#define PPI_GPS_GPSFLAGS_FLAG2_DIFFGPS   0x00000004
-#define PPI_GPS_GPSFLAGS_FLAG3_PPS       0x00000008
-#define PPI_GPS_GPSFLAGS_FLAG4_RTK       0x00000010
-#define PPI_GPS_GPSFLAGS_FLAG5_FLOATRTK  0x00000020
-#define PPI_GPS_GPSFLAGS_FLAG6_DEAD_RECK 0x00000040
-#define PPI_GPS_GPSFLAGS_FLAG7_MANUAL    0x00000080
-#define PPI_GPS_GPSFLAGS_FLAG8_SIM       0x00000100
-        { &hf_ppi_gps_gpsflags_flag0_nofix, /* no fix available */
-          { "No fix available", "ppi_gps.gpsflagss.nofix",
-            FT_BOOLEAN, 32, NULL, PPI_GPS_GPSFLAGS_FLAG0_NOFIX,
-            NULL, HFILL } },
-        { &hf_ppi_gps_gpsflags_flag1_gpsfix, /* GPSfix available */
-          { "GPS provided fix", "ppi_gps.gpsflagss.gps",
-            FT_BOOLEAN, 32, NULL, PPI_GPS_GPSFLAGS_FLAG1_GPS,
-            NULL, HFILL } },
-        { &hf_ppi_gps_gpsflags_flag2_diffgps, /* Differential GPS fix  available */
-          { "Differential GPS provided fix", "ppi_gps.gpsflagss.diffgps",
-            FT_BOOLEAN, 32, NULL, PPI_GPS_GPSFLAGS_FLAG2_DIFFGPS,
-            "DGPS provided fix", HFILL } },
-        { &hf_ppi_gps_gpsflags_flag3_PPS, /* PPS fix  */
-          { "PPS fix", "ppi_gps.gpsflagss.pps",
-            FT_BOOLEAN, 32, NULL, PPI_GPS_GPSFLAGS_FLAG3_PPS,
-            NULL, HFILL } },
-        { &hf_ppi_gps_gpsflags_flag4_RTK, /* RTK fix*/
-          { "RTK fix", "ppi_gps.gpsflagss.rtk",
-            FT_BOOLEAN, 32, NULL, PPI_GPS_GPSFLAGS_FLAG4_RTK,
-            NULL, HFILL } },
-        { &hf_ppi_gps_gpsflags_flag5_floatRTK, /*float RTK */
-          { "floatRTK fix", "ppi_gps.gpsflagss.frtk",
-            FT_BOOLEAN, 32, NULL, PPI_GPS_GPSFLAGS_FLAG5_FLOATRTK,
-            NULL, HFILL } },
-        { &hf_ppi_gps_gpsflags_flag6_dead_reck, /*dead reckoning */
-          { "dead reckoning fix", "ppi_gps.gpsflagss.dead_reck",
-            FT_BOOLEAN, 32, NULL, PPI_GPS_GPSFLAGS_FLAG6_DEAD_RECK,
-            NULL, HFILL } },
-        { &hf_ppi_gps_gpsflags_flag7_manual, /* manual */
-          { "manual fix", "ppi_gps.gpsflagss.manual",
-            FT_BOOLEAN, 32, NULL, PPI_GPS_GPSFLAGS_FLAG7_MANUAL,
-            NULL, HFILL } },
-        { &hf_ppi_gps_gpsflags_flag8_sim, /* simulation */
-          { "simulated fix", "ppi_gps.gpsflagss.simulation",
-            FT_BOOLEAN, 32, NULL, PPI_GPS_GPSFLAGS_FLAG8_SIM,
-            NULL, HFILL } },
-
-    };
-    static gint *ett[] = {
-        &ett_ppi_gps,
-        &ett_ppi_gps_present,
-        &ett_ppi_gps_gpsflags_flags
-    };
-
-    proto_ppi_gps = proto_register_protocol("PPI Geotagging GPS tag decoder", "PPI GPS Decoder", "ppi_gps");
-    proto_register_field_array(proto_ppi_gps, hf, array_length(hf));
-    proto_register_subtree_array(ett, array_length(ett));
-    register_dissector("ppi_gps", dissect_ppi_gps, proto_ppi_gps);
-
-}
 void dissect_ppi_gps(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree) {
     /* These are locals used for processing the current tvb */
     guint length;
@@ -347,6 +139,7 @@ void dissect_ppi_gps(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree) {
     proto_tree *my_pt, *gpsflags_flags_tree = NULL; /* used for DeviceType bitmask stuff */
 
     proto_item *ti = NULL;
+    proto_item *gps_line = NULL;
 
 
     /* bits */
@@ -358,6 +151,8 @@ void dissect_ppi_gps(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree) {
     nstime_t gps_timestamp;
     int gps_time_size, already_processed_fractime; /* we use this internally to track if this is a 4 or 8 byte wide timestamp */
     gdouble eph, epv, ept;
+    gchar *curr_str;
+
 
     /* these are temporary intermediate values, used in the individual cases below */
     guint32 t_lat, t_lon, t_alt, t_alt_gnd;
@@ -374,47 +169,47 @@ void dissect_ppi_gps(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree) {
     length = tvb_get_letohs(tvb, offset+2);
     present = tvb_get_letohl(tvb, offset+4);
 
+    /* Setup basic column info */
     if (check_col(pinfo->cinfo, COL_INFO))
         col_add_fstr(pinfo->cinfo, COL_INFO, "PPI_GPS Capture v%u, Length %u", version, length);
 
-    /* Dissect the packet */
+    /* Create the basic dissection tree*/
     if (tree) {
-        ti = proto_tree_add_protocol_format(tree, proto_ppi_gps,
-                                            tvb, 0, length, "PPI GPS Header v%u, Length %u", version, length);
+        ti = proto_tree_add_protocol_format(tree, proto_ppi_gps, tvb, 0, length, "GPS:");
+        gps_line = ti; /*we will make this more useful if we hit lon/lat later */
         ppi_gps_tree= proto_item_add_subtree(ti, ett_ppi_gps);
         proto_tree_add_uint(ppi_gps_tree, hf_ppi_gps_version, tvb, offset, 1, version);
         proto_tree_add_item(ppi_gps_tree, hf_ppi_gps_pad, tvb, offset + 1, 1, FALSE);
         ti = proto_tree_add_uint(ppi_gps_tree, hf_ppi_gps_length, tvb, offset + 2, 2, length);
     }
-    /* basic length sanity checking */
-    if (length > PPI_GPS_MAXTAGLEN ) {
+
+    /* We support v1 and v2 of GPS tags (identical) */
+    if (! (version == 1 || version == 2) ) {
         if (tree)
-            proto_item_append_text(ti, "Invalid PPI-GPS length  (got %d, %d max\n)", length, PPI_GPS_MAXTAGLEN);
+            proto_item_append_text(ti, "invalid version (got %d,  expected 1 or 2)", version);
         return;
     }
-    /* no minimum length check, technically zero is valid */
 
     /* initialize the length of the actual tag contents */
     length_remaining = length;
-    if (version != 1) {
-        if (tree)
-            proto_item_append_text(ti, "invalid version (got %d, expected 1)", version);
-        return;
-    }
-
-    /*
-     * This only works if there is exactly 1 present
-     * field in the header. This is not a problem as there are currently no extended bitmasks defined.
-     */
+    /* minimum length check, should atleast be a fixed-size geotagging-base header*/
     if (length_remaining < PPI_GEOBASE_MIN_HEADER_LEN) {
         /*
          * Base-geotag-header (Radiotap lookalike) is shorter than the fixed-length portion
          * plus one "present" bitset.
          */
         if (tree)
-            proto_item_append_text(ti, " (bogus - minimum length is 8)");
+            proto_item_append_text(ti, " (invalid - minimum length is 8)");
+        return;
+    }
+
+    /* perform tag-specific max length sanity checking */
+    if (length > PPI_GPS_MAXTAGLEN ) {
+        if (tree)
+            proto_item_append_text(ti, "Invalid PPI-GPS length  (got %d, %d max\n)", length, PPI_GPS_MAXTAGLEN);
         return;
     }
+
     /* Subtree for the "present flags" bitfield. */
     if (tree) {
         pt = proto_tree_add_uint(ppi_gps_tree, hf_ppi_gps_present, tvb, offset + 4, 4, present);
@@ -474,7 +269,10 @@ void dissect_ppi_gps(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree) {
             t_lat = tvb_get_letohl(tvb, offset);
             lat =  fixed3_7_to_gdouble(t_lat);
             if (tree)
+            {
                 proto_tree_add_double(ppi_gps_tree, hf_ppi_gps_lat, tvb, offset, 4, lat);
+                proto_item_append_text(gps_line, " Lat:%f ", lat);
+            }
             offset+=4;
             length_remaining-=4;
             break;
@@ -484,7 +282,10 @@ void dissect_ppi_gps(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree) {
             t_lon = tvb_get_letohl(tvb, offset);
             lon =  fixed3_7_to_gdouble(t_lon);
             if (tree)
+            {
                 proto_tree_add_double(ppi_gps_tree, hf_ppi_gps_lon, tvb, offset, 4, lon);
+                proto_item_append_text(gps_line, " Lon:%f ", lon);
+            }
             offset+=4;
             length_remaining-=4;
             break;
@@ -494,7 +295,10 @@ void dissect_ppi_gps(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree) {
             t_alt = tvb_get_letohl(tvb, offset);
             alt = fixed6_4_to_gdouble(t_alt);
             if (tree)
+            {
                 proto_tree_add_double(ppi_gps_tree, hf_ppi_gps_alt, tvb, offset, 4, alt);
+                proto_item_append_text(gps_line, " Alt:%f ", alt);
+            }
             offset+=4;
             length_remaining-=4;
             break;
@@ -504,7 +308,10 @@ void dissect_ppi_gps(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree) {
             t_alt_gnd = tvb_get_letohl(tvb, offset);
             alt_gnd = fixed6_4_to_gdouble(t_alt_gnd);
             if (tree)
+            {
                 proto_tree_add_double(ppi_gps_tree, hf_ppi_gps_alt_gnd, tvb, offset, 4, alt_gnd);
+                proto_item_append_text(gps_line, " Alt_g:%f ", alt_gnd);
+            }
             offset+=4;
             length_remaining-=4;
             break;
@@ -570,7 +377,12 @@ void dissect_ppi_gps(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree) {
             if (length_remaining < 32)
                 break;
             if (tree)
-                proto_tree_add_item(ppi_gps_tree, hf_ppi_gps_descr, tvb, offset, 32,  FALSE);
+            {
+                /* proto_tree_add_item(ppi_gps_tree, hf_ppi_gps_descstr, tvb, offset, 32,  FALSE); */
+                curr_str = tvb_format_text(tvb, offset, 32); /* need to append_text this */
+                proto_tree_add_string(ppi_gps_tree, hf_ppi_gps_descstr, tvb, offset, 32, curr_str);
+                proto_item_append_text(gps_line, " (%s)", curr_str);
+            }
             offset+=32;
             length_remaining-=32;
             break;
@@ -609,6 +421,215 @@ void dissect_ppi_gps(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree) {
     return;
 }
 
+void
+proto_register_ppi_gps(void) {
+    /* The following array initializes those header fields declared above to the values displayed */
+    static hf_register_info hf[] = {
+        { &hf_ppi_gps_version,
+            { "Header revision", "ppi_gps.version",
+                FT_UINT8, BASE_DEC, NULL, 0x0,
+                "Version of ppi_gps header format", HFILL } },
+        { &hf_ppi_gps_pad,
+          { "Header pad", "ppi_gps.pad",
+            FT_UINT8, BASE_DEC, NULL, 0x0,
+            "Padding", HFILL } },
+        { &hf_ppi_gps_length,
+          { "Header length", "ppi_gps.length",
+            FT_UINT16, BASE_DEC, NULL, 0x0,
+            "Length of header including version, pad, length and data fields", HFILL } },
+        { &hf_ppi_gps_present, /* these flag fields are composed of a uint32 on the display */
+          { "Present", "ppi_gps.present",
+            FT_UINT32, BASE_HEX, NULL, 0x0,
+            "Bitmask indicating which fields are present", HFILL } },
+
+        /* Boolean 'present' flags */
+        { &hf_ppi_gps_present_gpsflags_flags, /* followed by a lot of booleans */
+          { "GPSFlags", "ppi_gps.present.gpsflagss",
+            FT_BOOLEAN, 32, NULL, PPI_GPS_MASK_GPSFLAGS,
+            "32-bit bitmask indicating type of GPS fix (GPS/INS/software/etc)", HFILL } },
+        { &hf_ppi_gps_present_lat,
+          { "Lat", "ppi_gps.present.lat",
+            FT_BOOLEAN, 32, NULL, PPI_GPS_MASK_LAT,
+            "Specifies if the latitude field is present", HFILL } },
+
+        { &hf_ppi_gps_present_lon,
+          { "Lon", "ppi_gps.present.lon",
+            FT_BOOLEAN, 32, NULL, PPI_GPS_MASK_LON,
+            "Specifies if the longitude field is present", HFILL } },
+
+        { &hf_ppi_gps_present_alt,
+          { "Alt", "ppi_gps.present.alt",
+            FT_BOOLEAN, 32, NULL, PPI_GPS_MASK_ALT,
+            "Specifies if the altitude field is present", HFILL } },
+
+        { &hf_ppi_gps_present_alt_gnd,
+          { "Alt-gnd", "ppi_gps.present.alt_gnd",
+            FT_BOOLEAN, 32, NULL, PPI_GPS_MASK_ALT_G,
+            "Specifies if the altitude-g field is present", HFILL } },
+
+        { &hf_ppi_gps_present_gpstime,
+          { "GPStime", "ppi_gps.present.gpstime",
+            FT_BOOLEAN, 32, NULL, PPI_GPS_MASK_GPSTIME,
+            "Specifies if the GPS time field is present", HFILL } },
+
+
+        { &hf_ppi_gps_present_fractime,
+          { "fractime", "ppi_gps.present.fractime",
+            FT_BOOLEAN, 32, NULL, PPI_GPS_MASK_FRACTIME,
+            "Specifies if the fractional time field is present", HFILL } },
+
+
+        { &hf_ppi_gps_present_eph,
+          { "error_h", "ppi_gps.present.eph",
+            FT_BOOLEAN, 32, NULL, PPI_GPS_MASK_EPH,
+            "Specifies if the horizontal error field is present (eph)", HFILL } },
+
+        { &hf_ppi_gps_present_epv,
+          { "error_v", "ppi_gps.present.epv",
+            FT_BOOLEAN, 32, NULL, PPI_GPS_MASK_EPV,
+            "Specifies if the vertical error field present (epv)", HFILL } },
+
+
+        { &hf_ppi_gps_present_ept,
+          { "error_t", "ppi_gps.present.ept",
+            FT_BOOLEAN, 32, NULL, PPI_GPS_MASK_EPT,
+            "Specifies if the estimed time error field is present (ept)", HFILL } },
+
+        { &hf_ppi_gps_present_descr,
+          { "Description", "ppi_gps.present.descr",
+            FT_BOOLEAN, 32, NULL, PPI_GPS_MASK_DESCRSTR,
+            "Specifies if the (ASCII) description is present", HFILL } },
+
+        { &hf_ppi_gps_present_appspecific_num,
+          { "AppId", "ppi_gps.present.appid",
+            FT_BOOLEAN, 32, NULL, PPI_GPS_MASK_APPID,
+            "Specifies if the application specific field id is present", HFILL } },
+
+        { &hf_ppi_gps_present_appspecific_data,
+          { "AppData", "ppi_gps.present.appdata",
+            FT_BOOLEAN, 32, NULL, PPI_GPS_MASK_APPDATA,
+            "Specifies if the application specific data field  is present", HFILL } },
+
+        { &hf_ppi_gps_present_ext,
+          { "Ext", "ppi_gps.present.ext",
+            FT_BOOLEAN, 32, NULL, PPI_GPS_MASK_EXT,
+            "Specifies if there are any extensions to the header present", HFILL } },
+
+        /* ---Now we get to the actual data fields--- */
+
+        { &hf_ppi_gps_gpsflags_flags,
+          { "GPSFlags", "ppi_gps.gpsflags",
+            FT_UINT32, BASE_HEX, NULL, 0x0,
+            "Bitmask indicating GPS/INS/manual fix", HFILL } },
+        { &hf_ppi_gps_lat,
+          { "Latitude", "ppi_gps.lat",
+            FT_DOUBLE, BASE_NONE, NULL, 0x0,
+            "Latitude packet was received at", HFILL } },
+        { &hf_ppi_gps_lon,
+          { "Longitude", "ppi_gps.lon",
+            FT_DOUBLE, BASE_NONE, NULL, 0x0,
+            "Longitude packet was received at", HFILL } },
+        { &hf_ppi_gps_alt,
+          { "Altitude", "ppi_gps.alt",
+            FT_DOUBLE, BASE_NONE, NULL, 0x0,
+            "Altitude packet was received at", HFILL } },
+        { &hf_ppi_gps_alt_gnd,
+          { "Altitude_gnd", "ppi_gps.alt_gnd",
+            FT_DOUBLE, BASE_NONE, NULL, 0x0,
+            "Altitude packet was received at (relative to ground)", HFILL } },
+        { &hf_ppi_gps_gpstime,
+          { "GPSTimestamp", "ppi_gps.gpstime",
+            FT_ABSOLUTE_TIME, ABSOLUTE_TIME_UTC, NULL, 0x0,
+            "GPSTimestamp packet was received at", HFILL } },
+        { &hf_ppi_gps_fractime,
+          { "fractional Timestamp", "ppi_gps.fractime",
+            FT_DOUBLE, BASE_NONE, NULL, 0x0,
+            "fractional GPSTimestamp packet was received at", HFILL } },
+        { &hf_ppi_gps_eph,
+          { "Horizontal Error (m)", "ppi_gps.eph",
+            FT_DOUBLE, BASE_NONE, NULL, 0x0,
+            "Horizontal margin of error (meters)", HFILL } },
+        { &hf_ppi_gps_epv,
+          { "Vertical Error (m)", "ppi_gps.epv",
+            FT_DOUBLE, BASE_NONE, NULL, 0x0,
+            "Vertical margin of error (meters)", HFILL } },
+        { &hf_ppi_gps_ept,
+          { "Time Error (s)", "ppi_gps.ept",
+            FT_DOUBLE, BASE_NONE, NULL, 0x0,
+            "Time margin of error (secs)", HFILL } },
+        { &hf_ppi_gps_descstr,
+          { "Description", "ppi_gps.descr",
+            FT_STRING, BASE_NONE, NULL, 0x0,
+            NULL, HFILL } },
+        { &hf_ppi_gps_appspecific_num,
+          { "Application Specific id", "ppi_gps.appid",
+            FT_UINT32, BASE_HEX, NULL, 0x0,
+            "Application-specific identifier", HFILL } },
+        { &hf_ppi_gps_appspecific_data,
+          { "Application specific data", "ppi_gps.appdata",
+            FT_BYTES, BASE_NONE, NULL, 0x0,
+            NULL, HFILL } },
+
+        /* --- moving on to the 'FixType' flags --- */
+#define PPI_GPS_GPSFLAGS_FLAG0_NOFIX     0x00000001
+#define PPI_GPS_GPSFLAGS_FLAG1_GPS       0x00000002
+#define PPI_GPS_GPSFLAGS_FLAG2_DIFFGPS   0x00000004
+#define PPI_GPS_GPSFLAGS_FLAG3_PPS       0x00000008
+#define PPI_GPS_GPSFLAGS_FLAG4_RTK       0x00000010
+#define PPI_GPS_GPSFLAGS_FLAG5_FLOATRTK  0x00000020
+#define PPI_GPS_GPSFLAGS_FLAG6_DEAD_RECK 0x00000040
+#define PPI_GPS_GPSFLAGS_FLAG7_MANUAL    0x00000080
+#define PPI_GPS_GPSFLAGS_FLAG8_SIM       0x00000100
+        { &hf_ppi_gps_gpsflags_flag0_nofix, /* no fix available */
+          { "No fix available", "ppi_gps.gpsflagss.nofix",
+            FT_BOOLEAN, 32, NULL, PPI_GPS_GPSFLAGS_FLAG0_NOFIX,
+            NULL, HFILL } },
+        { &hf_ppi_gps_gpsflags_flag1_gpsfix, /* GPSfix available */
+          { "GPS provided fix", "ppi_gps.gpsflagss.gps",
+            FT_BOOLEAN, 32, NULL, PPI_GPS_GPSFLAGS_FLAG1_GPS,
+            NULL, HFILL } },
+        { &hf_ppi_gps_gpsflags_flag2_diffgps, /* Differential GPS fix  available */
+          { "Differential GPS provided fix", "ppi_gps.gpsflagss.diffgps",
+            FT_BOOLEAN, 32, NULL, PPI_GPS_GPSFLAGS_FLAG2_DIFFGPS,
+            "DGPS provided fix", HFILL } },
+        { &hf_ppi_gps_gpsflags_flag3_PPS, /* PPS fix  */
+          { "PPS fix", "ppi_gps.gpsflagss.pps",
+            FT_BOOLEAN, 32, NULL, PPI_GPS_GPSFLAGS_FLAG3_PPS,
+            NULL, HFILL } },
+        { &hf_ppi_gps_gpsflags_flag4_RTK, /* RTK fix*/
+          { "RTK fix", "ppi_gps.gpsflagss.rtk",
+            FT_BOOLEAN, 32, NULL, PPI_GPS_GPSFLAGS_FLAG4_RTK,
+            NULL, HFILL } },
+        { &hf_ppi_gps_gpsflags_flag5_floatRTK, /*float RTK */
+          { "floatRTK fix", "ppi_gps.gpsflagss.frtk",
+            FT_BOOLEAN, 32, NULL, PPI_GPS_GPSFLAGS_FLAG5_FLOATRTK,
+            NULL, HFILL } },
+        { &hf_ppi_gps_gpsflags_flag6_dead_reck, /*dead reckoning */
+          { "dead reckoning fix", "ppi_gps.gpsflagss.dead_reck",
+            FT_BOOLEAN, 32, NULL, PPI_GPS_GPSFLAGS_FLAG6_DEAD_RECK,
+            NULL, HFILL } },
+        { &hf_ppi_gps_gpsflags_flag7_manual, /* manual */
+          { "manual fix", "ppi_gps.gpsflagss.manual",
+            FT_BOOLEAN, 32, NULL, PPI_GPS_GPSFLAGS_FLAG7_MANUAL,
+            NULL, HFILL } },
+        { &hf_ppi_gps_gpsflags_flag8_sim, /* simulation */
+          { "simulated fix", "ppi_gps.gpsflagss.simulation",
+            FT_BOOLEAN, 32, NULL, PPI_GPS_GPSFLAGS_FLAG8_SIM,
+            NULL, HFILL } },
+
+    };
+    static gint *ett[] = {
+        &ett_ppi_gps,
+        &ett_ppi_gps_present,
+        &ett_ppi_gps_gpsflags_flags
+    };
+
+    proto_ppi_gps = proto_register_protocol("PPI Geotagging GPS tag decoder", "PPI GPS Decoder", "ppi_gps");
+    proto_register_field_array(proto_ppi_gps, hf, array_length(hf));
+    proto_register_subtree_array(ett, array_length(ett));
+    register_dissector("ppi_gps", dissect_ppi_gps, proto_ppi_gps);
+}
+
 /*
  * Editor modelines
  *
@@ -621,6 +642,3 @@ void dissect_ppi_gps(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree) {
  * ex: set shiftwidth=4 tabstop=8 expandtab
  * :indentSize=4:tabSize=8:noTabs=true:
  */
-
-
-