[GTPv2] Dissect ULI Timestamp.

Change-Id: If257831315423e5654cbbc3f6af99703cfad7f90
Reviewed-on: https://code.wireshark.org/review/7614
Reviewed-by: Anders Broman <a.broman58@gmail.com>

3 files changed, 63 insertions, 7 deletions

diff --git a/epan/dissectors/packet-gtpv2.c b/epan/dissectors/packet-gtpv2.c
index cbc3a2e572..1a2ff7cce9 100644
--- a/epan/dissectors/packet-gtpv2.c
+++ b/epan/dissectors/packet-gtpv2.c
@@ -408,6 +408,7 @@ static int hf_gtpv2_ip4cp_ipv4 = -1;
 static int hf_gtpv2_change_report_flags_sncr = -1;
 static int hf_gtpv2_change_report_flags_tzcr = -1;
 static int hf_gtpv2_action_indication_val = -1;
+static int hf_gtpv2_uli_timestamp = -1;
 static int hf_gtpv2_mbms_session_duration_days = -1;
 static int hf_gtpv2_mbms_session_duration_secs = -1;
 static int hf_gtpv2_node_features_prn = -1;
@@ -5280,7 +5281,16 @@ dissect_gtpv2_twan_Identifier(tvbuff_t *tvb, packet_info *pinfo _U_, proto_tree
 static void
 dissect_gtpv2_uli_timestamp(tvbuff_t *tvb, packet_info *pinfo _U_, proto_tree *tree, proto_item *item _U_, guint16 length _U_, guint8 message_type _U_, guint8 instance _U_)
 {
-    proto_tree_add_expert(tree, pinfo, &ei_gtpv2_ie_data_not_dissected, tvb, 0, length);
+	const gchar *time_str;
+
+	/* Octets 5 to 8 are encoded in the same format as the first four octets of the 64-bit timestamp
+	 * format as defined in section 6 of IETF RFC 5905
+	 */
+
+	time_str = tvb_ntp_fmt_ts_sec(tvb, 0);
+	proto_tree_add_string(tree, hf_gtpv2_uli_timestamp, tvb, 0, 8, time_str);
+	proto_item_append_text(item, "%s", time_str);
+
 }
 /*
  * 8.102        MBMS Flags
@@ -7504,12 +7514,17 @@ void proto_register_gtpv2(void)
           FT_UINT8, BASE_DEC|BASE_EXT_STRING, &gtpv2_action_indication_vals_ext, 0x07,
           NULL , HFILL}
         },
-        { &hf_gtpv2_abs_time_mbms_data,
-          {"Absolute Time of MBMS Data Transfer", "gtpv2.abs_time_mbms_data",
-           FT_STRING, BASE_NONE, NULL, 0,
-           NULL, HFILL}
-        },
-        { &hf_gtpv2_mbms_session_duration_days,
+		{ &hf_gtpv2_uli_timestamp,
+		{ "ULI Timestamp", "gtpv2.uli_timestamp",
+		FT_STRING, BASE_NONE, NULL, 0,
+		NULL, HFILL }
+		},
+		{ &hf_gtpv2_abs_time_mbms_data,
+		{ "Absolute Time of MBMS Data Transfer", "gtpv2.abs_time_mbms_data",
+		FT_STRING, BASE_NONE, NULL, 0,
+		NULL, HFILL }
+		},
+		{ &hf_gtpv2_mbms_session_duration_days,
           {"MBMS Session Duration (days)", "gtpv2.mbms_session_duration_days",
            FT_UINT24, BASE_DEC, NULL, 0x00007F,
            NULL, HFILL}
diff --git a/epan/dissectors/packet-ntp.c b/epan/dissectors/packet-ntp.c
index f338b9eb58..0d139ee2ab 100644
--- a/epan/dissectors/packet-ntp.c
+++ b/epan/dissectors/packet-ntp.c
@@ -704,6 +704,46 @@ tvb_ntp_fmt_ts(tvbuff_t *tvb, gint offset)
 	return buff;
 }
 
+/* tvb_ntp_fmt_ts_sec - converts an NTP timestamps second part (32bits) to an human readable string.
+* TVB and an offset (IN).
+* returns pointer to filled buffer.  This buffer will be freed automatically once
+* dissection of the next packet occurs.
+*/
+const char *
+tvb_ntp_fmt_ts_sec(tvbuff_t *tvb, gint offset)
+{
+	guint32		 tempstmp;
+	time_t		 temptime;
+	struct tm	*bd;
+	char		*buff;
+
+	tempstmp = tvb_get_ntohl(tvb, offset);
+	if (tempstmp == 0){
+		return "NULL";
+	}
+
+	/* We need a temporary variable here so the unsigned math
+	* works correctly (for years > 2036 according to RFC 2030
+	* chapter 3).
+	*/
+	temptime = (time_t)(tempstmp - NTP_BASETIME);
+	bd = gmtime(&temptime);
+	if (!bd){
+		return "Not representable";
+	}
+
+	buff = (char *)wmem_alloc(wmem_packet_scope(), NTP_TS_SIZE);
+	g_snprintf(buff, NTP_TS_SIZE,
+		"%s %2d, %d %02d:%02d:%02d UTC",
+		mon_names[bd->tm_mon],
+		bd->tm_mday,
+		bd->tm_year + 1900,
+		bd->tm_hour,
+		bd->tm_min,
+		bd->tm_sec);
+	return buff;
+}
+
 void
 ntp_to_nstime(tvbuff_t *tvb, gint offset, nstime_t *nstime)
 {
diff --git a/epan/dissectors/packet-ntp.h b/epan/dissectors/packet-ntp.h
index 0723e5cf44..b465d54c03 100644
--- a/epan/dissectors/packet-ntp.h
+++ b/epan/dissectors/packet-ntp.h
@@ -24,6 +24,7 @@
 #define PACKET_NTP_H
 
 extern const char *tvb_ntp_fmt_ts(tvbuff_t *tvb, gint offset);
+extern const char *tvb_ntp_fmt_ts_sec(tvbuff_t *tvb, gint offset);
 extern const char *tvb_mip6_fmt_ts(tvbuff_t *tvb, gint offset);
 extern void ntp_to_nstime(tvbuff_t *tvb, gint offset, nstime_t *nstime);