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| author | Jaap Keuter <jaap.keuter@xs4all.nl> | 2018-06-04 14:52:26 +0200 |
|---|---|---|
| committer | Anders Broman <a.broman58@gmail.com> | 2018-06-05 04:16:24 +0000 |
| commit | 447ffdf042e0eebf87ea9d33a9823e6d24345a0e (patch) | |
| tree | 808092498e2ff9ae1fac4a5f216f5a3ee069b325 /epan/dissectors/packet-ppi-gps.c | |
| parent | 8e7396edb4b4ac9580cdddb4feb0903da071905f (diff) | |
Correctly handle the PPI GPS timestamp fraction
The timestamp and timestamp fraction are processed in one step,
since this creates a proper timestamp interpretation. There are
two fixes to this code to deal with erroneous packets.
One is that when taking into account the timestamp fragment the
available data must be 8 bytes in total, not just 4.
The other is that when the mask indicates that there's only a
timestamp fraction, nothing was shown.
Change-Id: I4a0a65229f322ad56673a26ff6b3e769e994062d
Signed-off-by: Jaap Keuter <jaap.keuter@xs4all.nl>
Reviewed-on: https://code.wireshark.org/review/28007
Tested-by: Petri Dish Buildbot
Reviewed-by: Anders Broman <a.broman58@gmail.com>
Diffstat (limited to 'epan/dissectors/packet-ppi-gps.c')
| -rw-r--r-- | epan/dissectors/packet-ppi-gps.c | 13 |
1 files changed, 7 insertions, 6 deletions
diff --git a/epan/dissectors/packet-ppi-gps.c b/epan/dissectors/packet-ppi-gps.c index f421587dc7..0cb5d2fef2 100644 --- a/epan/dissectors/packet-ppi-gps.c +++ b/epan/dissectors/packet-ppi-gps.c @@ -68,7 +68,7 @@ static int hf_ppi_gps_lat = -1; static int hf_ppi_gps_alt = -1; static int hf_ppi_gps_alt_gnd = -1; static int hf_ppi_gps_gpstime = -1; -/* static int hf_ppi_gps_fractime = -1; */ +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; @@ -295,7 +295,7 @@ dissect_ppi_gps(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data /* This is somewhat tricky, inside the GPSTIME case we test if the optional fractional time */ /* is present. If so, we pull it out, and combine it with GPSTime. */ /* If we do this, we set already_processed_fractime to avoid hitting it below */ - if (length_remaining < 4 && (present & PPI_GPS_MASK_FRACTIME)) + if (length_remaining < 8 && (present & PPI_GPS_MASK_FRACTIME)) break; else if (present & PPI_GPS_MASK_FRACTIME) { gps_timestamp.nsecs = tvb_get_letohl(tvb, offset + 4); /* manually offset seconds */ @@ -311,6 +311,9 @@ dissect_ppi_gps(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data break; if (already_processed_fractime) break; + proto_tree_add_item(ppi_gps_tree, hf_ppi_gps_fractime, tvb, offset, 4, ENC_LITTLE_ENDIAN); + offset += 4; + length_remaining -= 4; break; case PPI_GEOTAG_EPH: if (length_remaining < 4) @@ -504,12 +507,10 @@ proto_register_ppi_gps(void) { { "GPSTimestamp", "ppi_gps.gpstime", FT_ABSOLUTE_TIME, ABSOLUTE_TIME_UTC, NULL, 0x0, "GPSTimestamp packet was received at", HFILL } }, -#if 0 { &hf_ppi_gps_fractime, { "fractional Timestamp", "ppi_gps.fractime", - FT_DOUBLE, BASE_NONE, NULL, 0x0, - "fractional GPSTimestamp packet was received at", HFILL } }, -#endif + FT_UINT32, BASE_DEC, NULL, 0x0, + "Fractional of GPSTimestamp packet was received at", HFILL } }, { &hf_ppi_gps_eph, { "Horizontal Error (m)", "ppi_gps.eph", FT_DOUBLE, BASE_NONE, NULL, 0x0, |