From Harald Welte:

Add new GSMTAP dissector.
https://bugs.wireshark.org/bugzilla/show_bug.cgi?id=4508
(I incorporated the .h file into the .c file).

svn path=/trunk/; revision=32214

1 files changed, 398 insertions, 0 deletions

diff --git a/epan/dissectors/packet-gsmtap.c b/epan/dissectors/packet-gsmtap.c
new file mode 100644
index 0000000000..ce330bc42e
--- /dev/null
+++ b/epan/dissectors/packet-gsmtap.c
@@ -0,0 +1,398 @@
+/* packet-gsmtap.c
+ * Routines for GSMTAP captures
+ *
+ * (C) 2008-2010 by Harald Welte <laforge@gnumonks.org>
+ *
+ * $Id$
+ *
+ * Wireshark - Network traffic analyzer
+ * By Gerald Combs <gerald@wireshark.org>
+ * Copyright 1998 Gerald Combs
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
+ * 02111-1307, USA.
+ *
+ */
+
+/* GSMTAP is a generic header format for GSM protocol captures,
+ * it uses the IANA-assigned UDP port number 4729 and carries
+ * payload in various formats of GSM interfaces such as Um MAC
+ * blocks or Um bursts.
+ *
+ * Example programs generating GSMTAP data are airprobe
+ * (http://airprobe.org/) or OsmocomBB (http://bb.osmocom.org/)
+ */
+
+#ifdef HAVE_CONFIG_H
+# include "config.h"
+#endif
+
+#include <glib.h>
+#include <epan/packet.h>
+#include <epan/prefs.h>
+
+#define GSMTAP_TYPE_UM			0x01
+#define GSMTAP_TYPE_ABIS		0x02
+#define GSMTAP_TYPE_UM_BURST	0x03	/* raw burst bits */
+
+#define GSMTAP_BURST_UNKNOWN		0x00
+#define GSMTAP_BURST_FCCH			0x01
+#define GSMTAP_BURST_PARTIAL_SCH	0x02
+#define GSMTAP_BURST_SCH			0x03
+#define GSMTAP_BURST_CTS_SCH		0x04
+#define GSMTAP_BURST_COMPACT_SCH	0x05
+#define GSMTAP_BURST_NORMAL			0x06
+#define GSMTAP_BURST_DUMMY			0x07
+#define GSMTAP_BURST_ACCESS			0x08
+#define GSMTAP_BURST_NONE			0x09
+
+#define GSMTAP_CHANNEL_UNKNOWN	0x00
+#define GSMTAP_CHANNEL_BCCH		0x01
+#define GSMTAP_CHANNEL_CCCH		0x02
+#define GSMTAP_CHANNEL_RACH		0x03
+#define GSMTAP_CHANNEL_AGCH		0x04
+#define GSMTAP_CHANNEL_PCH		0x05
+#define GSMTAP_CHANNEL_SDCCH	0x06
+#define GSMTAP_CHANNEL_SDCCH4	0x07
+#define GSMTAP_CHANNEL_SDCCH8	0x08
+#define GSMTAP_CHANNEL_TCH_F	0x09
+#define GSMTAP_CHANNEL_TCH_H	0x0a
+#define GSMTAP_CHANNEL_ACCH		0x80
+
+#define GSMTAP_ARFCN_F_PCS		0x8000
+#define GSMTAP_ARFCN_F_UPLINK	0x4000
+#define GSMTAP_ARFCN_MASK		0x3fff
+
+#define GSMTAP_UDP_PORT			4729
+
+/* This is the header as it is used by gsmtap-generating software.
+ * It is not used by the wireshark dissector and provided for reference only.
+struct gsmtap_hdr {
+	guint8 version;		// version, set to 0x01 currently
+	guint8 hdr_len;		// length in number of 32bit words
+	guint8 type;		// see GSMTAP_TYPE_*
+	guint8 timeslot;	// timeslot (0..7 on Um)
+
+	guint16 arfcn;		// ARFCN (frequency)
+	gint8 signal_dbm;	// signal level in dBm
+	gint8 snr_db;		// signal/noise ratio in dB
+
+	guint32 frame_number;	// GSM Frame Number (FN)
+
+	guint8 sub_type;	// Type of burst/channel, see above
+	guint8 antenna_nr;	// Antenna Number
+	guint8 sub_slot;	// sub-slot within timeslot
+	guint8 res;		// reserved for future use (RFU)
+}
+ */
+
+static int proto_gsmtap = -1;
+
+static int hf_gsmtap_version = -1;
+static int hf_gsmtap_hdrlen = -1;
+static int hf_gsmtap_type = -1;
+static int hf_gsmtap_timeslot = -1;
+static int hf_gsmtap_subslot = -1;
+static int hf_gsmtap_arfcn = -1;
+static int hf_gsmtap_uplink = -1;
+static int hf_gsmtap_noise_dbm = -1;
+static int hf_gsmtap_signal_dbm = -1;
+static int hf_gsmtap_frame_nr = -1;
+static int hf_gsmtap_burst_type = -1;
+static int hf_gsmtap_channel_type = -1;
+static int hf_gsmtap_antenna = -1;
+
+static int hf_sacch_l1h_power_lev = -1;
+static int hf_sacch_l1h_fpc = -1;
+static int hf_sacch_l1h_ta = -1;
+
+static gint ett_gsmtap = -1;
+
+enum {
+	GSMTAP_SUB_DATA = 0,
+	GSMTAP_SUB_UM,
+	GSMTAP_SUB_UM_LAPDM,
+	GSMTAP_SUB_ABIS,
+
+	GSMTAP_SUB_MAX
+};
+
+static dissector_handle_t sub_handles[GSMTAP_SUB_MAX];
+
+static const value_string gsmtap_bursts[] = {
+	{ GSMTAP_BURST_UNKNOWN,		"UNKNOWN" },
+	{ GSMTAP_BURST_FCCH,		"FCCH" },
+	{ GSMTAP_BURST_PARTIAL_SCH,	"PARTIAL SCH" },
+	{ GSMTAP_BURST_SCH,			"SCH" },
+	{ GSMTAP_BURST_CTS_SCH,		"CTS SCH" },
+	{ GSMTAP_BURST_COMPACT_SCH,	"COMPACT SCH" },
+	{ GSMTAP_BURST_NORMAL,		"NORMAL" },
+	{ GSMTAP_BURST_DUMMY,		"DUMMY" },
+	{ GSMTAP_BURST_ACCESS,		"RACH" },
+	{ 0,				NULL },
+};
+
+static const value_string gsmtap_channels[] = {
+	{ GSMTAP_CHANNEL_UNKNOWN,	"UNKNOWN" },
+	{ GSMTAP_CHANNEL_BCCH,		"BCCH" },
+	{ GSMTAP_CHANNEL_CCCH,		"CCCH" },
+	{ GSMTAP_CHANNEL_RACH,		"RACH" },
+	{ GSMTAP_CHANNEL_AGCH,		"AGCH" },
+	{ GSMTAP_CHANNEL_PCH,		"PCH" },
+	{ GSMTAP_CHANNEL_SDCCH,		"SDCCH" },
+	{ GSMTAP_CHANNEL_SDCCH4,	"SDCCH/4" },
+	{ GSMTAP_CHANNEL_SDCCH8,	"SDCCH/8" },
+	{ GSMTAP_CHANNEL_TCH_F,		"FACCH/F" },
+	{ GSMTAP_CHANNEL_TCH_H,		"FACCH/H" },
+	{ GSMTAP_CHANNEL_ACCH|
+	  GSMTAP_CHANNEL_SDCCH,		"LSACCH" },
+	{ GSMTAP_CHANNEL_ACCH|
+	  GSMTAP_CHANNEL_SDCCH4,	"SACCH/4" },
+	{ GSMTAP_CHANNEL_ACCH|
+	  GSMTAP_CHANNEL_SDCCH8,	"SACCH/8" },
+	{ GSMTAP_CHANNEL_ACCH|
+	  GSMTAP_CHANNEL_TCH_F,		"SACCH/F" },
+	{ GSMTAP_CHANNEL_ACCH|
+	  GSMTAP_CHANNEL_TCH_F,		"SACCH/H" },
+	{ 0,				NULL },
+};
+
+static const value_string gsmtap_types[] = {
+	{ GSMTAP_TYPE_UM,	"GSM Um (MS<->BTS)" },
+	{ GSMTAP_TYPE_ABIS,	"GSM Abis (BTS<->BSC)" },
+	{ GSMTAP_TYPE_UM_BURST,	"GSM Um burst (MS<->BTS)" },
+	{ 0,			NULL },
+};
+
+/* dissect a SACCH L1 header which is included in the first 2 bytes
+ * of every SACCH frame (according to TS 04.04) */
+static void
+dissect_sacch_l1h(tvbuff_t *tvb, proto_tree *tree)
+{
+	proto_item *ti;
+	proto_tree *l1h_tree = NULL;
+
+	if (!tree)
+		return;
+
+	ti = proto_tree_add_protocol_format(tree, proto_gsmtap, tvb, 0, 2,
+			"SACCH L1 Header, Power Level: %u, Timing Advance: %u",
+			tvb_get_guint8(tvb, 0) & 0x1f,
+			tvb_get_guint8(tvb, 1));
+	l1h_tree = proto_item_add_subtree(ti, ett_gsmtap);
+	/* Power Level */
+	proto_tree_add_item(l1h_tree, hf_sacch_l1h_power_lev, tvb, 0, 1, FALSE);
+	/* Fast Power Control */
+	proto_tree_add_item(l1h_tree, hf_sacch_l1h_fpc, tvb, 0, 1, FALSE);
+	/* Acutal Timing Advance */
+	proto_tree_add_item(l1h_tree, hf_sacch_l1h_ta, tvb, 1, 1, FALSE);
+}
+
+/* dissect a GSMTAP header and hand payload off to respective dissector */
+static void
+dissect_gsmtap(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
+{
+	int sub_handle, len, offset = 0;
+	proto_item *ti;
+	proto_tree *gsmtap_tree = NULL;
+	tvbuff_t *payload_tvb, *l1h_tvb = NULL;
+	guint8 hdr_len, type, sub_type;
+	guint16 arfcn;
+
+	len = tvb_length(tvb);
+
+	hdr_len = tvb_get_guint8(tvb, offset + 1) <<2;
+	type = tvb_get_guint8(tvb, offset + 2);
+	sub_type = tvb_get_guint8(tvb, offset + 12);
+	arfcn = tvb_get_ntohs(tvb, offset + 4);
+
+	/* In case of a SACCH, there is a two-byte L1 header in front
+	 * of the packet (see TS 04.04) */
+	if (type == GSMTAP_TYPE_UM &&
+	    sub_type & GSMTAP_CHANNEL_ACCH) {
+		l1h_tvb = tvb_new_subset(tvb, hdr_len, 2, 2);
+		payload_tvb = tvb_new_subset(tvb, hdr_len+2, len-(hdr_len+2),
+					     len-(hdr_len+2));
+	} else {
+		payload_tvb = tvb_new_subset(tvb, hdr_len, len-hdr_len,
+					     len-hdr_len);
+	}
+
+	/* We don't want any UDP related info left in the INFO field, as the
+	 * gsm_a_dtap dissector will not clear but only append */
+	col_clear(pinfo->cinfo, COL_INFO);
+
+	col_set_str(pinfo->cinfo, COL_PROTOCOL, "GSMTAP");
+
+	if (arfcn & GSMTAP_ARFCN_F_UPLINK) {
+		col_append_str(pinfo->cinfo, COL_RES_NET_SRC, "MS");
+		col_append_str(pinfo->cinfo, COL_RES_NET_DST, "BTS");
+		/* p2p_dir is used by the LAPDm dissector */
+		pinfo->p2p_dir = P2P_DIR_SENT;
+	} else {
+		col_set_str(pinfo->cinfo, COL_RES_NET_SRC, "BTS");
+		switch (sub_type & ~GSMTAP_CHANNEL_ACCH) {
+		case GSMTAP_CHANNEL_BCCH:
+		case GSMTAP_CHANNEL_CCCH:
+		case GSMTAP_CHANNEL_PCH:
+		case GSMTAP_CHANNEL_AGCH:
+			col_set_str(pinfo->cinfo, COL_RES_NET_DST, "Broadcast");
+			break;
+		default:
+			col_set_str(pinfo->cinfo, COL_RES_NET_DST, "MS");
+			break;
+		}
+		/* p2p_dir is used by the LAPDm dissector */
+		pinfo->p2p_dir = P2P_DIR_RECV;
+	}
+
+	if (tree) {
+		ti = proto_tree_add_protocol_format(tree, proto_gsmtap, tvb, 0, hdr_len,
+			"GSM TAP Header, ARFCN: %u (%s), TS: %u, Channel: %s (%u)",
+			arfcn & GSMTAP_ARFCN_MASK,
+			arfcn & GSMTAP_ARFCN_F_UPLINK ? "Uplink" : "Downlink",
+			tvb_get_guint8(tvb, offset+3),
+			match_strval(tvb_get_guint8(tvb, offset+12), gsmtap_channels),
+			tvb_get_guint8(tvb, offset+14));
+		gsmtap_tree = proto_item_add_subtree(ti, ett_gsmtap);
+		proto_tree_add_item(gsmtap_tree, hf_gsmtap_version,
+				    tvb, offset, 1, FALSE);
+		proto_tree_add_uint_format(gsmtap_tree, hf_gsmtap_hdrlen,
+				    tvb, offset+1, 1, hdr_len,
+				    "Header length: %u bytes", hdr_len);
+		proto_tree_add_item(gsmtap_tree, hf_gsmtap_type,
+				    tvb, offset+2, 1, FALSE);
+		proto_tree_add_item(gsmtap_tree, hf_gsmtap_timeslot,
+				    tvb, offset+3, 1, FALSE);
+		proto_tree_add_item(gsmtap_tree, hf_gsmtap_arfcn,
+				    tvb, offset+4, 2, FALSE);
+		proto_tree_add_item(gsmtap_tree, hf_gsmtap_uplink,
+				    tvb, offset+4, 2, FALSE);
+		proto_tree_add_item(gsmtap_tree, hf_gsmtap_noise_dbm,
+				    tvb, offset+6, 1, FALSE);
+		proto_tree_add_item(gsmtap_tree, hf_gsmtap_signal_dbm,
+				    tvb, offset+7, 1, FALSE);
+		proto_tree_add_item(gsmtap_tree, hf_gsmtap_frame_nr,
+				    tvb, offset+8, 4, FALSE);
+		if (type == GSMTAP_TYPE_UM_BURST)
+			proto_tree_add_item(gsmtap_tree, hf_gsmtap_burst_type,
+					    tvb, offset+12, 1, FALSE);
+		else if (type == GSMTAP_TYPE_UM)
+			proto_tree_add_item(gsmtap_tree, hf_gsmtap_channel_type,
+					    tvb, offset+12, 1, FALSE);
+		proto_tree_add_item(gsmtap_tree, hf_gsmtap_antenna,
+				    tvb, offset+13, 1, FALSE);
+		proto_tree_add_item(gsmtap_tree, hf_gsmtap_subslot,
+				    tvb, offset+14, 1, FALSE);
+	}
+
+	switch (type) {
+	case GSMTAP_TYPE_UM:
+		if (l1h_tvb)
+			dissect_sacch_l1h(l1h_tvb, tree);
+		switch (sub_type & ~GSMTAP_CHANNEL_ACCH) {
+		case GSMTAP_CHANNEL_BCCH:
+		case GSMTAP_CHANNEL_CCCH:
+		case GSMTAP_CHANNEL_PCH:
+		case GSMTAP_CHANNEL_AGCH:
+			/* FIXME: we might want to skip idle frames */
+			sub_handle = GSMTAP_SUB_UM;
+			break;
+		case GSMTAP_CHANNEL_SDCCH:
+		case GSMTAP_CHANNEL_SDCCH4:
+		case GSMTAP_CHANNEL_SDCCH8:
+		case GSMTAP_CHANNEL_TCH_F:
+		case GSMTAP_CHANNEL_TCH_H:
+			sub_handle = GSMTAP_SUB_UM_LAPDM;
+			break;
+		case GSMTAP_CHANNEL_RACH:
+		default:
+			sub_handle = GSMTAP_SUB_DATA;
+			break;
+		}
+		break;
+	case GSMTAP_TYPE_UM_BURST:
+	default:
+		sub_handle = GSMTAP_SUB_DATA;
+		break;
+	}
+	call_dissector(sub_handles[sub_handle], payload_tvb, pinfo, tree);
+}
+
+static const true_false_string sacch_l1h_fpc_mode_vals = {
+	"In use",
+	"Not in use"
+};
+
+void
+proto_register_gsmtap(void)
+{
+	static hf_register_info hf[] = {
+		{ &hf_gsmtap_version, { "Version", "gsmtap.version",
+		  FT_UINT8, BASE_DEC, NULL, 0, NULL, HFILL } },
+		{ &hf_gsmtap_hdrlen, { "Header Length", "gsmtap.hdr_len",
+		  FT_UINT8, BASE_DEC, NULL, 0, NULL, HFILL } },
+		{ &hf_gsmtap_type, { "Payload Type", "gsmtap.type",
+		  FT_UINT8, BASE_DEC, VALS(gsmtap_types), 0, NULL, HFILL } },
+		{ &hf_gsmtap_timeslot, { "Time Slot", "gsmtap.ts",
+		  FT_UINT8, BASE_DEC, NULL, 0, NULL, HFILL } },
+		{ &hf_gsmtap_arfcn, { "ARFCN", "gsmtap.arfcn",
+		  FT_UINT16, BASE_DEC, NULL, GSMTAP_ARFCN_MASK, NULL, HFILL } },
+		{ &hf_gsmtap_uplink, { "Uplink", "gsmtap.uplink",
+		  FT_UINT16, BASE_DEC, NULL, GSMTAP_ARFCN_F_UPLINK, NULL, HFILL } },
+		{ &hf_gsmtap_noise_dbm, { "Signal/Noise Ratio (dB)", "gsmtap.snr_db",
+		  FT_UINT8, BASE_DEC, NULL, 0, NULL, HFILL } },
+		{ &hf_gsmtap_signal_dbm, { "Signal Level (dBm)", "gsmtap.signal_dbm",
+		  FT_UINT8, BASE_DEC, NULL, 0, NULL, HFILL } },
+		{ &hf_gsmtap_frame_nr, { "GSM Frame Number", "gsmtap.frame_nr",
+		  FT_UINT32, BASE_DEC, NULL, 0, NULL, HFILL } },
+		{ &hf_gsmtap_burst_type, { "Burst Type", "gsmtap.burst_type",
+		  FT_UINT8, BASE_DEC, VALS(gsmtap_bursts), 0, NULL, HFILL }},
+		{ &hf_gsmtap_channel_type, { "Channel Type", "gsmtap.chan_type",
+		  FT_UINT8, BASE_DEC, VALS(gsmtap_channels), 0, NULL, HFILL }},
+		{ &hf_gsmtap_antenna, { "Antenna Number", "gsmtap.antenna",
+		  FT_UINT8, BASE_DEC, NULL, 0, NULL, HFILL } },
+		{ &hf_gsmtap_subslot, { "Sub-Slot", "gsmtap.sub_slot",
+		  FT_UINT8, BASE_DEC, NULL, 0, NULL, HFILL } },
+
+		{ &hf_sacch_l1h_power_lev, { "MS power level", "gsmtap.sacch_l1.power_lev",
+		  FT_UINT8, BASE_DEC, NULL, 0x1f, NULL, HFILL } },
+		{ &hf_sacch_l1h_fpc, { "FPC", "gsmtap.sacch_l1.fpc",
+		  FT_BOOLEAN, 8, TFS(&sacch_l1h_fpc_mode_vals), 0x04,
+		  NULL, HFILL } },
+		{ &hf_sacch_l1h_ta, { "Actual Timing Advance", "gsmtap.sacch_l1.ta",
+		  FT_UINT8, BASE_DEC, NULL, 0, NULL, HFILL } },
+	};
+	static gint *ett[] = {
+		&ett_gsmtap
+	};
+
+	proto_gsmtap = proto_register_protocol("GSM Radiotap", "GSMTAP", "gsmtap");
+	proto_register_field_array(proto_gsmtap, hf, array_length(hf));
+	proto_register_subtree_array(ett, array_length(ett));
+}
+
+void
+proto_reg_handoff_gsmtap(void)
+{
+	dissector_handle_t gsmtap_handle;
+
+	sub_handles[GSMTAP_SUB_DATA] = find_dissector("data");
+	sub_handles[GSMTAP_SUB_UM] = find_dissector("gsm_a_ccch");
+	sub_handles[GSMTAP_SUB_UM_LAPDM] = find_dissector("lapdm");
+	sub_handles[GSMTAP_SUB_ABIS] = find_dissector("gsm_a_dtap");
+	gsmtap_handle = create_dissector_handle(dissect_gsmtap, proto_gsmtap);
+	dissector_add("udp.port", GSMTAP_UDP_PORT, gsmtap_handle);
+}