From Sylvain Munaut: Add support LAPSat : GMR-1 Datalink layer https://bugs.wireshark.org/bugzilla/show_bug.cgi?id=6918

svn path=/trunk/; revision=41404

1 files changed, 767 insertions, 0 deletions

diff --git a/epan/dissectors/packet-lapsat.c b/epan/dissectors/packet-lapsat.c
new file mode 100644
index 0000000000..fb0aeacd48
--- /dev/null
+++ b/epan/dissectors/packet-lapsat.c
@@ -0,0 +1,767 @@
+/* packet-lapsat.c
+ *
+ * Routines for GMR-1 LAPSat dissection in wireshark.
+ *
+ * Link Access Procedures (LAP) for the Satellite Channel (LAPSat).
+ * LAPSat is the protocol for signalling transfer between an Access
+ * Terminal (MES) and a Gateway Station (GS) in the GeoMobile (GMR-1) network.
+ *
+ * Copyright (c) 2011 Sylvain Munaut <tnt@246tNt.com>
+ * Inspired on LAPDm code by Duncan Salerno <duncan.salerno@googlemail.com>
+ *
+ * References:
+ *  [1] ETSI TS 101 376-4-6 V1.2.1 - GMR-1 04.006
+ *
+ * $Id$
+ *
+ * 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.
+ */
+
+#ifdef HAVE_CONFIG_H
+# include "config.h"
+#endif
+
+#include <glib.h>
+#include <epan/packet.h>
+#include <epan/reassemble.h>
+
+
+static int proto_lapsat = -1;
+
+static GHashTable *lapsat_fragment_table = NULL;
+static GHashTable *lapsat_reassembled_table = NULL;
+
+static dissector_table_t lapsat_sapi_dissector_table;
+
+static dissector_handle_t data_handle;
+
+static gint ett_lapsat = -1;
+static gint ett_lapsat_address = -1;
+static gint ett_lapsat_control = -1;
+static gint ett_lapsat_fragment = -1;
+static gint ett_lapsat_fragments = -1;
+
+static int hf_lapsat_addr = -1;
+static int hf_lapsat_addr_sst = -1;
+static int hf_lapsat_addr_cr = -1;
+static int hf_lapsat_addr_sapi = -1;
+static int hf_lapsat_addr_si = -1;
+static int hf_lapsat_addr_lpd = -1;
+static int hf_lapsat_addr_lfi = -1;
+
+static int hf_lapsat_ctl = -1;
+static int hf_lapsat_ctl_ftype_i = -1;
+static int hf_lapsat_ctl_ftype_s_u = -1;
+static int hf_lapsat_ctl_s_ftype = -1;
+static int hf_lapsat_ctl_u_modifier_cmd = -1;
+static int hf_lapsat_ctl_u_modifier_resp = -1;
+static int hf_lapsat_ctl_n_r = -1;
+static int hf_lapsat_ctl_n_s = -1;
+static int hf_lapsat_ctl_p = -1;
+static int hf_lapsat_ctl_f = -1;
+static int hf_lapsat_ctl_mii = -1;
+
+static int hf_lapsat_payload_last_nibble = -1;
+
+static int hf_lapsat_len = -1;
+
+static int hf_lapsat_fragments = -1;
+static int hf_lapsat_fragment = -1;
+static int hf_lapsat_fragment_overlap = -1;
+static int hf_lapsat_fragment_overlap_conflicts = -1;
+static int hf_lapsat_fragment_multiple_tails = -1;
+static int hf_lapsat_fragment_too_long_fragment = -1;
+static int hf_lapsat_fragment_error = -1;
+static int hf_lapsat_fragment_count = -1;
+static int hf_lapsat_reassembled_in = -1;
+static int hf_lapsat_reassembled_length = -1;
+
+
+#define LAPSAT_HEADER_LEN		3
+
+#define LAPSAT_SAPI_RR_CC_MM		0
+#define LAPSAT_SAPI_SMS			3
+
+
+/*
+ * Address field bits
+ */
+
+#define LAPSAT_SST			0x01	/* SACCH status bit */
+#define LAPSAT_CR			0x02	/* Command/Response bit */
+#define LAPSAT_SAPI_MSK			0x0c	/* Service Access Point Identifier */
+#define LAPSAT_SAPI_SHIFT		2
+#define LAPSAT_SI			0x10	/* Segment Indicator */
+#define LAPSAT_LPD_MSK			0x60	/* DL for LAPSat or SMS-CB */
+#define LAPSAT_LPD_SHIFT		6
+#define LAPSAT_LFI			0x80	/* Length Field Indicator */
+
+static const value_string lapsat_addr_sst_vals[] = {
+	{ 0, "FACCH and all other messages" },
+	{ 1, "SACCH message" },
+	{ 0 , NULL }
+};
+
+static const value_string lapsat_addr_sapi_vals[] = {
+	{ LAPSAT_SAPI_RR_CC_MM, "RR/MM/CC" },
+	{ LAPSAT_SAPI_SMS, "SMS/SS" },
+	{ 0, NULL }
+};
+
+static const value_string lapsat_addr_lpd_vals[] = {
+	{ 0, "Normal GMR-1" },
+	{ 1, "Cell broadcast service" },
+	{ 0, NULL }
+};
+
+static const value_string lapsat_addr_si_vals[] = {
+	{ 0, "Complete/Last Segment of L3 message" },
+	{ 1, "Segment only" },
+	{ 0, NULL }
+};
+
+static const value_string lapsat_addr_lfi_vals[] = {
+	{ 0, "Length Field not present (all data valid)" },
+	{ 1, "Length Field present" },
+	{ 0, NULL }
+};
+
+
+/*
+ * Frame types
+ */
+
+#define LAPSAT_CTL_TYPE_S		0x001
+#define	LAPSAT_CTL_TYPE_U		0x003
+#define LAPSAT_CTL_TYPE_S_U_MSK		0x003
+
+#define	LAPSAT_CTL_TYPE_I		0x000
+#define	LAPSAT_CTL_TYPE_I_MSK		0x001
+
+static const value_string lapsat_ctl_ftype_vals[] = {
+	{ LAPSAT_CTL_TYPE_I, "Information frame" },
+	{ LAPSAT_CTL_TYPE_S, "Supervisory frame" },
+	{ LAPSAT_CTL_TYPE_U, "Unnumbered frame" },
+	{ 0, NULL }
+};
+
+
+/*
+ * S-format frame types
+ */
+
+#define LAPSAT_CTL_S_FTYPE_MSK		0x00c
+
+#define LAPSAT_RR			0x000
+#define LAPSAT_GREJ			0x008
+
+static const value_string lapsat_ctl_s_ftype_vals[] = {
+	{ LAPSAT_RR >> 2,   "Receiver ready" },
+	{ LAPSAT_GREJ >> 2, "Group reject" },
+	{ 0, NULL}
+};
+
+
+/*
+ * U-format modifiers
+ */
+
+#define LAPSAT_CTL_U_MODIFIER_MSK	0x18c
+
+#define LAPSAT_SABM			0x08c
+#define LAPSAT_DM			0x00c
+#define LAPSAT_DISC			0x100
+#define LAPSAT_UA			0x180
+#define LAPSAT_UI			0x000
+
+static const value_string lapsat_ctl_u_modifier_vals_cmd[] = {
+	{ LAPSAT_SABM >> 2, "Set Asynchronous Balanced Mode" },
+	{ LAPSAT_DISC >> 2, "Disconnect" },
+	{ LAPSAT_UI >> 2,   "Unnumbered Information" },
+	{ 0, NULL}
+};
+
+static const value_string lapsat_ctl_u_modifier_vals_resp[] = {
+	{ LAPSAT_DM >> 2,   "Disconnected mode" },
+	{ LAPSAT_UA >> 2,   "Unnumbered Acknowledge" },
+	{ 0, NULL}
+};
+
+
+/*
+ * Control fields
+ */
+
+#define LAPSAT_CTL_P_F			0x040
+#define LAPSAT_CTL_MII			0x200
+#define LAPSAT_CTL_N_R_MSK		0xf80
+#define LAPSAT_CTL_N_R_SHIFT		7
+#define LAPSAT_CTL_N_S_MSK		0x03e
+#define LAPSAT_CTL_N_S_SHIFT		1
+
+
+/*
+ * Fragment stuff
+ */
+
+static const value_string true_false_vals[] = {
+	{ 0, "False" },
+	{ 1, "True" },
+	{ 0, NULL },
+};
+
+
+static const fragment_items lapsat_frag_items = {
+	/* Fragment subtrees */
+	&ett_lapsat_fragment,
+	&ett_lapsat_fragments,
+	/* Fragment fields */
+	&hf_lapsat_fragments,
+	&hf_lapsat_fragment,
+	&hf_lapsat_fragment_overlap,
+	&hf_lapsat_fragment_overlap_conflicts,
+	&hf_lapsat_fragment_multiple_tails,
+	&hf_lapsat_fragment_too_long_fragment,
+	&hf_lapsat_fragment_error,
+	&hf_lapsat_fragment_count,
+	/* Reassembled in field */
+	&hf_lapsat_reassembled_in,
+	/* Reassembled length field */
+	&hf_lapsat_reassembled_length,
+	/* Tag */
+	"fragments"
+};
+
+static void
+lapsat_defragment_init(void)
+{
+	fragment_table_init(&lapsat_fragment_table);
+	reassembled_table_init(&lapsat_reassembled_table);
+}
+
+
+/*
+ * Main dissection functions
+ */
+
+static guint16
+dissect_control(tvbuff_t *tvb, packet_info *pinfo _U_, proto_tree *tree, int is_response)
+{
+	proto_tree *ctl_tree;
+	proto_item *ctl_ti;
+	guint16 ctl, poll_final;
+	const char *frame_type;
+	char *info;
+
+	info = ep_alloc(80);
+
+	/* Grab complete control field */
+	ctl = tvb_get_ntohs(tvb, 1) >> 4;
+
+	poll_final = ctl & LAPSAT_CTL_P_F;
+
+	/* Generate small 'descriptive' text */
+	switch (ctl & LAPSAT_CTL_TYPE_S_U_MSK) {
+	case LAPSAT_CTL_TYPE_S:
+		/*
+		 * Supervisory frame.
+		 */
+		switch (ctl & LAPSAT_CTL_S_FTYPE_MSK) {
+		case LAPSAT_RR:
+			frame_type = "RR";
+			break;
+		case LAPSAT_GREJ:
+			frame_type = "GREJ";
+			break;
+		default:
+			frame_type = "Unknown";
+			break;
+		}
+
+		g_snprintf(info, 80, "S%s, func=%s, N(R)=%u",
+			poll_final ? (is_response ? " F" : " P") : "",
+			frame_type,
+			(ctl & LAPSAT_CTL_N_R_MSK) >> LAPSAT_CTL_N_R_SHIFT);
+
+		break;
+
+	case LAPSAT_CTL_TYPE_U:
+		/*
+		 * Unnumbered frame
+		 */
+		switch (ctl & LAPSAT_CTL_U_MODIFIER_MSK) {
+		case LAPSAT_SABM:
+			frame_type = (ctl & LAPSAT_CTL_MII) ?
+				"SABM, MII=1" : "SABM, MII=0";
+			break;
+		case LAPSAT_DM:
+			frame_type = "DM";
+			break;
+		case LAPSAT_DISC:
+			frame_type = "DISC";
+			break;
+		case LAPSAT_UA:
+			frame_type = "UA";
+			break;
+		case LAPSAT_UI:
+			frame_type = "UI";
+			break;
+		default:
+			frame_type = "Unknown";
+			break;
+		}
+
+		g_snprintf(info, 80, "U%s, func=%s",
+			poll_final ? (is_response ? " F" : " P") : "",
+			frame_type);
+
+		break;
+
+	default:
+		/*
+		 * Information frame
+		 */
+		g_snprintf(info, 80, "I%s, N(R)=%u, N(S)=%u",
+			poll_final ? " P" : "",
+			(ctl & LAPSAT_CTL_N_R_MSK) >> LAPSAT_CTL_N_R_SHIFT,
+			(ctl & LAPSAT_CTL_N_S_MSK) >> LAPSAT_CTL_N_S_SHIFT);
+
+		break;
+	}
+
+	/* Add info */
+	if (check_col(pinfo->cinfo, COL_INFO))
+		col_add_str(pinfo->cinfo, COL_INFO, info);
+
+	/* Create item & subtree */
+	ctl_ti = proto_tree_add_uint_format_value(
+			tree, hf_lapsat_ctl,
+			tvb, 1, 2, (guint32)ctl,
+			"%s (0x%03x)", info, ctl
+	);
+
+	ctl_tree = proto_item_add_subtree(ctl_ti, ett_lapsat_control);
+
+	/* Add all fields */
+	switch (ctl & LAPSAT_CTL_TYPE_S_U_MSK) {
+	case LAPSAT_CTL_TYPE_S:
+		/*
+		 * Supervisory frame.
+		 */
+
+		proto_tree_add_item(ctl_tree, hf_lapsat_ctl_ftype_s_u,
+		                    tvb, 1, 2, ENC_BIG_ENDIAN);
+
+		proto_tree_add_item(ctl_tree, hf_lapsat_ctl_s_ftype,
+		                    tvb, 1, 2, ENC_BIG_ENDIAN);
+
+		proto_tree_add_item(ctl_tree, hf_lapsat_ctl_n_r,
+		                    tvb, 1, 2, ENC_BIG_ENDIAN);
+
+		if (poll_final)
+			proto_tree_add_item(ctl_tree,
+				is_response ? hf_lapsat_ctl_f : hf_lapsat_ctl_p,
+				tvb, 1, 2, ENC_BIG_ENDIAN);
+
+		break;
+
+	case LAPSAT_CTL_TYPE_U:
+		/*
+		 * Unnumbered frame
+		 */
+
+		proto_tree_add_item(ctl_tree, hf_lapsat_ctl_ftype_s_u,
+		                    tvb, 1, 2, ENC_BIG_ENDIAN);
+
+		proto_tree_add_item(ctl_tree,
+			is_response ?	hf_lapsat_ctl_u_modifier_resp :
+					hf_lapsat_ctl_u_modifier_cmd,
+			tvb, 1, 2, ENC_BIG_ENDIAN);
+
+		if (poll_final)
+			proto_tree_add_item(ctl_tree,
+				is_response ? hf_lapsat_ctl_f : hf_lapsat_ctl_p,
+				tvb, 1, 2, ENC_BIG_ENDIAN);
+
+		if (((ctl & LAPSAT_CTL_U_MODIFIER_MSK) == LAPSAT_SABM) &&
+		     (ctl & LAPSAT_CTL_MII))
+			proto_tree_add_item(ctl_tree, hf_lapsat_ctl_mii,
+			                    tvb, 1, 2, ENC_BIG_ENDIAN);
+
+		break;
+
+	default:
+		/*
+		 * Information frame
+		 */
+
+		proto_tree_add_item(ctl_tree, hf_lapsat_ctl_ftype_i,
+		                    tvb, 1, 2, ENC_BIG_ENDIAN);
+
+		proto_tree_add_item(ctl_tree, hf_lapsat_ctl_n_r,
+		                    tvb, 1, 2, ENC_BIG_ENDIAN);
+
+		proto_tree_add_item(ctl_tree, hf_lapsat_ctl_n_s,
+		                    tvb, 1, 2, ENC_BIG_ENDIAN);
+
+		if (poll_final)
+			proto_tree_add_item(ctl_tree, hf_lapsat_ctl_p,
+					    tvb, 1, 2, ENC_BIG_ENDIAN);
+
+		break;
+	}
+
+	return ctl;
+}
+
+static void
+dissect_lapsat(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
+{
+	proto_tree *lapsat_tree, *addr_tree;
+	proto_item *lapsat_ti, *addr_ti;
+	tvbuff_t *payload;
+	guint8 addr, sapi, cr;
+	guint16 control;
+	unsigned int hlen, is_response = 0, plen;
+
+	/* Check that there's enough data */
+	if (tvb_length(tvb) < LAPSAT_HEADER_LEN)
+		return;
+
+	/* Set protocol column */
+	col_set_str(pinfo->cinfo, COL_PROTOCOL, "LAPSat");
+
+	/* Grab a couple of fields */
+	addr = tvb_get_guint8(tvb, 0);
+
+	sapi = (addr & LAPSAT_SAPI_MSK) >> LAPSAT_SAPI_SHIFT;
+
+	cr = addr & LAPSAT_CR;
+	if (pinfo->p2p_dir == P2P_DIR_RECV) {
+		is_response = cr ? FALSE : TRUE;
+	}
+	else if (pinfo->p2p_dir == P2P_DIR_SENT) {
+		is_response = cr ? TRUE : FALSE;
+	}
+
+	hlen = LAPSAT_HEADER_LEN;
+
+	if (addr & LAPSAT_LFI)
+		hlen++;
+
+		/* FIXME if "S func=GREJ", extend */
+
+	/* Create LAPSat tree */
+	lapsat_ti = proto_tree_add_item(tree, proto_lapsat, tvb, 0, hlen, ENC_BIG_ENDIAN);
+	lapsat_tree = proto_item_add_subtree(lapsat_ti, ett_lapsat);
+
+	/* Dissect address field */
+	addr_ti = proto_tree_add_item(lapsat_tree, hf_lapsat_addr, tvb, 0, 1, ENC_BIG_ENDIAN);
+	addr_tree = proto_item_add_subtree(addr_ti, ett_lapsat_address);
+
+	proto_tree_add_item(addr_tree, hf_lapsat_addr_sst,  tvb, 0, 1, ENC_BIG_ENDIAN);
+	proto_tree_add_item(addr_tree, hf_lapsat_addr_cr,   tvb, 0, 1, ENC_BIG_ENDIAN);
+	proto_tree_add_item(addr_tree, hf_lapsat_addr_sapi, tvb, 0, 1, ENC_BIG_ENDIAN);
+	proto_tree_add_item(addr_tree, hf_lapsat_addr_si,   tvb, 0, 1, ENC_BIG_ENDIAN);
+	proto_tree_add_item(addr_tree, hf_lapsat_addr_lpd,  tvb, 0, 1, ENC_BIG_ENDIAN);
+	proto_tree_add_item(addr_tree, hf_lapsat_addr_lfi,  tvb, 0, 1, ENC_BIG_ENDIAN);
+
+	/* Dissect control field */
+	control = dissect_control(tvb, pinfo, lapsat_tree, is_response);
+
+	/* Last payload nibble */
+	proto_tree_add_item(lapsat_tree, hf_lapsat_payload_last_nibble, tvb, 2, 1, ENC_BIG_ENDIAN);
+
+	/* Optional length field */
+	if (addr & LAPSAT_LFI)
+		proto_tree_add_item(lapsat_tree, hf_lapsat_len, tvb, 3, 1, ENC_BIG_ENDIAN);
+
+	/* If frame is "S func=GREJ", then add Na(R) & Nb(R) */
+		/* FIXME */
+
+	/* Get the payload */
+	plen = (addr & LAPSAT_LFI) ?
+		tvb_get_guint8(tvb, 3) : tvb_length(tvb) - hlen;
+
+	if (!plen)
+		return;	/* No point in doing more if there is no payload */
+
+	DISSECTOR_ASSERT((plen + hlen) <= tvb_length(tvb));
+
+	if ((plen + hlen) == tvb_length(tvb)) {
+		/* Need to integrate the last nibble */
+		guint8 *data = ep_alloc(plen);
+		tvb_memcpy(tvb, data, hlen, plen);
+		data[plen-1] |= tvb_get_guint8(tvb, 2) << 4;
+		payload = tvb_new_child_real_data(tvb, data, plen, plen);
+	} else {
+		/* Last nibble doesn't need merging */
+		payload = tvb_new_subset(tvb, hlen, plen, -1);
+	}
+
+	add_new_data_source(pinfo, payload, "LAPSat Payload");
+
+	/* Handle fragments */
+	if ((control & LAPSAT_CTL_TYPE_I_MSK) == LAPSAT_CTL_TYPE_I) {
+		/*
+		 * Potentially fragmented I frames
+		 */
+		fragment_data *fd_m = NULL;
+		tvbuff_t *reassembled = NULL;
+		guint32 fragment_id;
+		gboolean save_fragmented = pinfo->fragmented;
+
+		/* Is this a fragment ? */
+		pinfo->fragmented = !!(addr & LAPSAT_SI);
+
+		/* Rely on caller to provide a way to group fragments */
+		fragment_id = (pinfo->circuit_id << 3) | (sapi << 1) | pinfo->p2p_dir;
+
+		/* Fragment reconstruction helpers */
+		fd_m = fragment_add_seq_next(
+			payload, 0, pinfo,
+			fragment_id,		/* To group fragments */
+			lapsat_fragment_table,
+			lapsat_reassembled_table,
+			plen,
+			!!(addr & LAPSAT_SI)	/* More fragment ? */
+		);
+
+		reassembled = process_reassembled_data(
+			payload, 0, pinfo,
+			"Reassembled LAPSat", fd_m, &lapsat_frag_items,
+			NULL, lapsat_tree
+		);
+
+		/* Reassembled into this packet ? */
+		if (fd_m && pinfo->fd->num == fd_m->reassembled_in) {
+			/* Yes, so handoff to upper layers */
+			if (!dissector_try_uint(lapsat_sapi_dissector_table, sapi,
+			                        reassembled, pinfo, tree))
+				call_dissector(data_handle, reassembled, pinfo, tree);
+		} else {
+			/* No, just add infos */
+			col_append_str(pinfo->cinfo, COL_INFO, " (Fragment)");
+			proto_tree_add_text(lapsat_tree, payload, 0, -1, "Fragment Data");
+		}
+
+		/* Now reset fragmentation information in pinfo */
+		pinfo->fragmented = save_fragmented;
+	} else {
+		/*
+		 * Whole frame
+		 */
+		if (!dissector_try_uint(lapsat_sapi_dissector_table, sapi, payload, pinfo, tree))
+			call_dissector(data_handle, payload, pinfo, tree);
+	}
+}
+
+void
+proto_register_lapsat(void)
+{
+	static hf_register_info hf[] = {
+		/* Address field */
+		{ &hf_lapsat_addr,
+		  { "Address Field", "lapsat.address",
+		    FT_UINT8, BASE_HEX, NULL, 0x00,
+		    NULL, HFILL },
+		},
+		{ &hf_lapsat_addr_sst,
+		  { "SST", "lapsat.address.sst",
+		    FT_UINT8, BASE_DEC, VALS(lapsat_addr_sst_vals), LAPSAT_SST,
+		    "SACCH status bit", HFILL },
+		},
+		{ &hf_lapsat_addr_cr,
+		  { "C/R", "lapsat.address.cr",
+		    FT_UINT8, BASE_DEC, NULL, LAPSAT_CR,
+		    "Command/response bit", HFILL },
+		},
+		{ &hf_lapsat_addr_sapi,
+		  { "SAPI", "lapsat.address.sapi",
+		    FT_UINT8, BASE_DEC, VALS(lapsat_addr_sapi_vals), LAPSAT_SAPI_MSK,
+		    "Service access point identifier", HFILL },
+		},
+		{ &hf_lapsat_addr_si,
+		  { "SI", "lapsat.address.si",
+		    FT_UINT8, BASE_DEC, VALS(lapsat_addr_si_vals), LAPSAT_SI,
+		    "Segment Indicator", HFILL },
+		},
+		{ &hf_lapsat_addr_lpd,
+		  { "LPD", "lapsat.address.lpd",
+		    FT_UINT8, BASE_DEC, VALS(lapsat_addr_lpd_vals), LAPSAT_LPD_MSK,
+		    "Link Protocol Discriminator", HFILL },
+		},
+		{ &hf_lapsat_addr_lfi,
+		  { "LFI", "lapsat.address.lfi",
+		    FT_UINT8, BASE_DEC, VALS(lapsat_addr_lfi_vals), LAPSAT_LFI,
+		    "Length Field Indicator", HFILL },
+		},
+
+		/* Control field */
+		{ &hf_lapsat_ctl,
+		  { "Control Field", "lapsat.control_field",
+		    FT_UINT16, BASE_HEX, NULL, 0x00,
+		    NULL, HFILL }
+		},
+		{ &hf_lapsat_ctl_ftype_i,
+		  { "Frame type", "lapsat.control.ftype",
+		    FT_UINT16, BASE_DEC, VALS(lapsat_ctl_ftype_vals), LAPSAT_CTL_TYPE_I_MSK << 4,
+		    NULL, HFILL }
+		},
+		{ &hf_lapsat_ctl_ftype_s_u,
+		  { "Frame type", "lapsat.control.ftype",
+		    FT_UINT16, BASE_DEC, VALS(lapsat_ctl_ftype_vals), LAPSAT_CTL_TYPE_S_U_MSK << 4,
+		    NULL, HFILL }
+		},
+		{ &hf_lapsat_ctl_s_ftype,
+		  { "Supervisory frame type", "lapsat.control.s_ftype",
+		    FT_UINT16, BASE_DEC, VALS(lapsat_ctl_s_ftype_vals), LAPSAT_CTL_S_FTYPE_MSK << 4,
+		    NULL, HFILL }
+		},
+		{ &hf_lapsat_ctl_u_modifier_cmd,
+		  { "Command", "lapsat.control.u_modifier_cmd",
+		    FT_UINT16, BASE_HEX, VALS(lapsat_ctl_u_modifier_vals_cmd),
+		    LAPSAT_CTL_U_MODIFIER_MSK << 4,
+		    NULL, HFILL }
+		},
+		{ &hf_lapsat_ctl_u_modifier_resp,
+		  { "Response", "lapsat.control.u_modifier_resp",
+		    FT_UINT16, BASE_HEX, VALS(lapsat_ctl_u_modifier_vals_resp),
+		    LAPSAT_CTL_U_MODIFIER_MSK << 4,
+		    NULL, HFILL }
+		},
+		{ &hf_lapsat_ctl_n_r,
+		  { "N(R)", "lapsat.control.n_r",
+		    FT_UINT16, BASE_DEC, NULL, LAPSAT_CTL_N_R_MSK << 4,
+		    NULL, HFILL }
+		},
+		{ &hf_lapsat_ctl_n_s,
+		  { "N(S)", "lapsat.control.n_s",
+		    FT_UINT16, BASE_DEC, NULL, LAPSAT_CTL_N_S_MSK << 4,
+		    NULL, HFILL }
+		},
+		{ &hf_lapsat_ctl_p,
+		  { "Poll", "lapsat.control.p",
+		    FT_UINT16, BASE_DEC, VALS(true_false_vals), LAPSAT_CTL_P_F << 4,
+		    NULL, HFILL }
+		},
+		{ &hf_lapsat_ctl_f,
+		  { "Final", "lapsat.control.f",
+		    FT_UINT16, BASE_DEC, VALS(true_false_vals), LAPSAT_CTL_P_F << 4,
+		    NULL, HFILL }
+		},
+		{ &hf_lapsat_ctl_mii,
+		  { "MII", "lapsat.control.mii",
+		    FT_UINT16, BASE_DEC, VALS(true_false_vals), LAPSAT_CTL_MII << 4,
+		    "Mobile Identity Indicator", HFILL }
+		},
+
+		/* Payload last nibble */
+		{ &hf_lapsat_payload_last_nibble,
+		  { "Payload last nibble", "lapsat.payload.last_nibble",
+		    FT_UINT8, BASE_HEX, NULL, 0x0f,
+		    NULL, HFILL }
+		},
+
+		/* Length field */
+		{ &hf_lapsat_len,
+		  { "Length Field", "lapsat.length",
+		    FT_UINT8, BASE_DEC, NULL, 0x00,
+		    NULL, HFILL },
+		},
+
+		/* Fragment reassembly */
+		{ &hf_lapsat_fragments,
+		  { "Message fragments", "lapsat.fragments",
+		    FT_NONE, BASE_NONE, NULL, 0x00,
+		    "LAPSat Message fragments", HFILL }
+		},
+		{ &hf_lapsat_fragment,
+		  { "Message fragment", "lapsat.fragment",
+		    FT_FRAMENUM, BASE_NONE, NULL, 0x00,
+		    "LAPSat Message fragment", HFILL }
+		},
+		{ &hf_lapsat_fragment_overlap,
+		  { "Message fragment overlap", "lapsat.fragment.overlap",
+		    FT_BOOLEAN, BASE_NONE, NULL, 0x0,
+		    "LAPSat Message fragment overlaps with other fragment(s)", HFILL }
+		},
+		{ &hf_lapsat_fragment_overlap_conflicts,
+		  { "Message fragment overlapping with conflicting data",
+		    "lapsat.fragment.overlap.conflicts",
+		    FT_BOOLEAN, BASE_NONE, NULL, 0x0,
+		    "LAPSat Message fragment overlaps with conflicting data", HFILL }
+		},
+		{ &hf_lapsat_fragment_multiple_tails,
+		  { "Message has multiple tail fragments", "lapsat.fragment.multiple_tails",
+		    FT_BOOLEAN, BASE_NONE, NULL, 0x0,
+		    "LAPSat Message fragment has multiple tail fragments", HFILL }
+		},
+		{ &hf_lapsat_fragment_too_long_fragment,
+		  { "Message fragment too long", "lapsat.fragment.too_long_fragment",
+		    FT_BOOLEAN, BASE_NONE, NULL, 0x0,
+		    "LAPSat Message fragment data goes beyond the packet end", HFILL }
+		},
+		{ &hf_lapsat_fragment_error,
+		  { "Message defragmentation error", "lapsat.fragment.error",
+		    FT_FRAMENUM, BASE_NONE, NULL, 0x00,
+		    "LAPSat Message defragmentation error due to illegal fragments", HFILL }
+		},
+		{ &hf_lapsat_fragment_count,
+		  { "Message fragment count", "lapsat.fragment.count",
+		    FT_UINT32, BASE_DEC, NULL, 0x00,
+		    NULL, HFILL }
+		},
+		{ &hf_lapsat_reassembled_in,
+		  { "Reassembled in", "lapsat.reassembled.in",
+		    FT_FRAMENUM, BASE_NONE, NULL, 0x00,
+		    "LAPSat Message has been reassembled in this packet.", HFILL }
+		},
+		{ &hf_lapsat_reassembled_length,
+		  { "Reassembled LAPSat length", "lapsat.reassembled.length",
+		    FT_UINT32, BASE_DEC, NULL, 0x00,
+		    "The total length of the reassembled payload", HFILL }
+		},
+	};
+
+	static gint *ett[] = {
+		&ett_lapsat,
+		&ett_lapsat_address,
+		&ett_lapsat_control,
+		&ett_lapsat_fragment,
+		&ett_lapsat_fragments,
+	};
+
+	proto_lapsat = proto_register_protocol("Link Access Procedure, Satellite channel (LAPSat)", "LAPSat", "lapsat");
+
+	proto_register_field_array (proto_lapsat, hf, array_length(hf));
+	proto_register_subtree_array(ett, array_length(ett));
+
+	register_dissector("lapsat", dissect_lapsat, proto_lapsat);
+
+	lapsat_sapi_dissector_table = register_dissector_table("lapsat.sapi", "LAPSat SAPI", FT_UINT8, BASE_DEC);
+
+	register_init_routine (lapsat_defragment_init);
+}
+
+void
+proto_reg_handoff_lapsat(void)
+{
+	data_handle = find_dissector("data");
+}