Wireshark · Wireshark-dev: [Wireshark-dev] [PATCH] new dissector for ip.access GSM A-bis over IP

[Harald Welte <laforge@xxxxxxxxxxxx>]

Hi!

I've written the following wireshark dissector for the GSM A-bis over IP
protocol as it is used with ip.access nanoBTS products.  The code was written
while developing OpenBSC (see http://openbsc.gnumonks.org/).

I'd like to request its inclusion into the wireshark mainline tree.  Please
review and let me know if there are any issues.

I'm also in the process of writing a generic GSM 12.21 (A-bis OML) dissector,
as well as extending the packet-rsl.c with ip.access nanoBTS vendor extensions.
I'm not sure when those will be finished, but I expect to post them within the
next couple of weeks.

Regards,
	Harald

Index: epan/dissectors/Makefile.common
===================================================================
--- epan/dissectors/Makefile.common.orig	2009-07-03 22:19:54.000000000 +0200
+++ epan/dissectors/Makefile.common	2009-07-03 22:20:16.000000000 +0200
@@ -471,6 +471,7 @@
 	packet-gsm_a_gm.c		\
 	packet-gsm_a_rp.c		\
 	packet-gsm_a_rr.c	\
+	packet-gsm_abis_ip.c	\
 	packet-gsm_bsslap.c		\
 	packet-gsm_bssmap_le.c	\
 	packet-gsm_sms.c	\
Index: epan/dissectors/packet-rsl.c
===================================================================
--- epan/dissectors/packet-rsl.c.orig	2009-07-03 22:19:54.000000000 +0200
+++ epan/dissectors/packet-rsl.c	2009-07-03 22:20:16.000000000 +0200
@@ -3950,6 +3950,7 @@
 	proto_register_field_array(proto_rsl, hf, array_length(hf));
 	proto_register_subtree_array(ett, array_length(ett));
 
+	register_dissector("gsm_abis_rsl", dissect_rsl, proto_rsl);
 
 }
 
Index: epan/dissectors/packet-gsm_abis_ip.c
===================================================================
--- /dev/null	1970-01-01 00:00:00.000000000 +0000
+++ epan/dissectors/packet-gsm_abis_ip.c	2009-07-03 22:20:16.000000000 +0200
@@ -0,0 +1,279 @@
+/* packet-gsm_abis_ip.c
+ * Routines for packet dissection of ip.access A-bis over IP
+ * Copyright 2009 by Harald Welte <laforge@xxxxxxxxxxxx>
+ *
+ * $Id$
+ *
+ * Wireshark - Network traffic analyzer
+ * By Gerald Combs <gerald@xxxxxxxxxxxxx>
+ * 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/emem.h>
+
+/* Initialize the protocol and registered fields */
+static int proto_abisip = -1;
+static int proto_ipaccess = -1;
+
+static int hf_abisip_data_len = -1;
+static int hf_abisip_protocol = -1;
+
+static int hf_ipaccess_msgtype = -1;
+static int hf_ipaccess_attr_tag = -1;
+static int hf_ipaccess_attr_string = -1;
+
+/* Initialize the subtree pointers */
+static gint ett_abisip = -1;
+static gint ett_ipaccess = -1;
+
+enum {
+	SUB_OML,
+	SUB_RSL,
+	SUB_IPACCESS,
+
+	SUB_MAX
+};
+
+static dissector_handle_t sub_handles[SUB_MAX];
+
+#define TCP_PORT_ABISIP_PRIM	 3002
+#define TCP_PORT_ABISIP_SEC	 3003
+#define TCP_PORT_ABISIP_INST	 3006
+
+#define ABISIP_RSL	0x00
+#define ABISIP_IPACCESS	0xfe
+#define ABISIP_OML	0xff
+
+static const value_string abisip_protocol_vals[] = {
+	{ 0x00,		"RSL" },
+	{ 0xfe,		"IPA" },
+	{ 0xff,		"OML" },
+	{ 0, 		NULL }
+};
+
+static const value_string ipaccess_msgtype_vals[] = {
+	{ 0x00,		"PING?" },
+	{ 0x01, 	"PONG!" },
+	{ 0x04, 	"IDENTITY REQUEST" },
+	{ 0x05, 	"IDENTITY RESPONSE" },
+	{ 0x06, 	"IDENTITY CONF" },
+	{ 0,		NULL }
+};
+
+static const value_string ipaccess_idtag_vals[] = {
+	{ 0x00,		"Serial Number" },
+	{ 0x01,		"Unit Name" },
+	{ 0x02,		"Location" },
+	{ 0x04,		"Equipment Version" },
+	{ 0x05,		"Software Version" },
+	{ 0x06,		"IP Address" },
+	{ 0x07,		"MAC Address" },
+	{ 0x08,		"Unit ID" },
+};
+
+static gint
+dissect_ipa_attr(tvbuff_t *tvb, int base_offs, proto_tree *tree)
+{
+	guint8 len, tag, attr_type;
+
+	int offset = base_offs;
+
+	while (tvb_reported_length_remaining(tvb, offset) != 0) {
+		attr_type = tvb_get_guint8(tvb, offset);
+
+		switch (attr_type) {
+		case 0x00:	/* a string prefixed by its length */
+			len = tvb_get_guint8(tvb, offset+1);
+			tag = tvb_get_guint8(tvb, offset+2);
+			proto_tree_add_item(tree, hf_ipaccess_attr_tag,
+					    tvb, offset+2, 1, FALSE);
+			proto_tree_add_item(tree, hf_ipaccess_attr_string,
+					    tvb, offset+3, len-1, FALSE);
+			break;
+		case 0x01:	/* a single-byte reqest for a certain attr */
+			len = 0;
+			proto_tree_add_item(tree, hf_ipaccess_attr_tag,
+					    tvb, offset+1, 1, FALSE);
+			break;
+		};
+		offset += len + 2;
+	};
+	return offset;
+}
+
+/* Dissect an ip.access specific message */
+static gint
+dissect_ipaccess(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
+{
+	proto_item *ti;
+	proto_tree *ipaccess_tree;
+	guint8 msg_type;
+
+	msg_type = tvb_get_guint8(tvb, 0);
+
+	if (check_col(pinfo->cinfo, COL_INFO))
+		col_append_fstr(pinfo->cinfo, COL_INFO, "%s ",
+				val_to_str(msg_type, ipaccess_msgtype_vals,
+					   "unknown 0x%02x"));
+	if (tree) {
+		ti = proto_tree_add_item(tree, proto_ipaccess, tvb, 0, -1, FALSE);
+		ipaccess_tree = proto_item_add_subtree(ti, ett_ipaccess);
+		proto_tree_add_item(ipaccess_tree, hf_ipaccess_msgtype,
+				    tvb, 0, 1, FALSE);
+		switch (msg_type) {
+		case 4:
+		case 5:
+			dissect_ipa_attr(tvb, 1, ipaccess_tree);
+			break;
+		}
+	}
+
+	return 1;
+}
+
+
+/* Code to actually dissect the packets */
+static void
+dissect_abisip(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
+{
+
+	int offset = 0;
+
+	if (check_col(pinfo->cinfo, COL_PROTOCOL))
+		col_set_str(pinfo->cinfo, COL_PROTOCOL, "Abis/IP");
+	if (check_col(pinfo->cinfo, COL_INFO))
+		col_clear(pinfo->cinfo, COL_INFO);
+
+	while (tvb_reported_length_remaining(tvb, offset) != 0) {
+		proto_item *ti;
+		proto_tree *abisip_tree;
+		guint8 len, msg_type;
+		tvbuff_t *next_tvb;
+
+		len = tvb_get_guint8(tvb, offset+1);
+		msg_type = tvb_get_guint8(tvb, offset+2);
+
+		if (check_col(pinfo->cinfo, COL_INFO))
+			col_append_fstr(pinfo->cinfo, COL_INFO, "%s ",
+				     val_to_str(msg_type, abisip_protocol_vals,
+						   "unknown 0x%02x"));
+
+		if (tree) {
+			ti = proto_tree_add_protocol_format(tree, proto_abisip,
+					tvb, offset, len+3,
+					"A-bis/IP protocol ip.access, type: %s",
+					val_to_str(msg_type, abisip_protocol_vals,
+						   "unknown 0x%02x"));
+			abisip_tree = proto_item_add_subtree(ti, ett_abisip);
+			proto_tree_add_item(abisip_tree, hf_abisip_data_len,
+					    tvb, offset+1, 1, FALSE);
+			proto_tree_add_item(abisip_tree, hf_abisip_protocol,
+					    tvb, offset+2, 1, FALSE);
+		}
+
+		next_tvb = tvb_new_subset(tvb, offset+3, len, len);
+
+		switch (msg_type) {
+		case ABISIP_RSL:
+			/* hand this off to the standard A-bis RSL dissector */
+			call_dissector(sub_handles[SUB_RSL], next_tvb, pinfo, tree);
+			break;
+		case ABISIP_OML:
+			/* hand this off to the standard A-bis OML dissector */
+			if (sub_handles[SUB_OML])
+				call_dissector(sub_handles[SUB_OML], next_tvb,
+						 pinfo, tree);
+			break;
+		case ABISIP_IPACCESS:
+			dissect_ipaccess(next_tvb, pinfo, tree);
+			break;
+		}
+		offset += len + 3;
+	}
+}
+
+void proto_register_abis_ip(void)
+{
+	static hf_register_info hf[] = {
+		{&hf_abisip_data_len,
+		 {"DataLen", "abisip.data_len",
+		  FT_UINT8, BASE_DEC, NULL, 0x0,
+		  "The length of the data (in bytes)", HFILL}
+		 },
+		{&hf_abisip_protocol,
+		 {"Protocol", "abisip.protocol",
+		  FT_UINT8, BASE_HEX, VALS(abisip_protocol_vals), 0x0,
+		  "The A-bis/IP Sub-Protocol", HFILL}
+		 },
+	};
+	static hf_register_info hf_ipa[] = {
+		{&hf_ipaccess_msgtype,
+		 {"MessageType", "ipaccess.msg_type",
+		  FT_UINT8, BASE_HEX, VALS(ipaccess_msgtype_vals), 0x0,
+		  "Type of ip.access messsage", HFILL}
+		 },
+		{&hf_ipaccess_attr_tag,
+		 {"Tag", "ipaccess.attr_tag",
+		  FT_UINT8, BASE_HEX, VALS(ipaccess_idtag_vals), 0x0,
+		  "Attribute Tag", HFILL}
+		 },
+		{&hf_ipaccess_attr_string,
+		 {"String", "ipaccess.attr_string",
+		  FT_STRING, BASE_NONE, NULL, 0x0,
+		  "String attribute", HFILL}
+		 },
+	};
+
+	static gint *ett[] = {
+		&ett_abisip,
+		&ett_ipaccess,
+	};
+
+	proto_abisip =
+	    proto_register_protocol("GSM A-bis/IP protocol as used by ip.access",
+				    "GSM A-bis/IP", "gsm_abis_ip");
+	proto_ipaccess =
+	    proto_register_protocol("GSM A-bis/IP ip.access CCM sub-protocol",
+				    "IPA", "ipaccess");
+
+	proto_register_field_array(proto_abisip, hf, array_length(hf));
+	proto_register_field_array(proto_ipaccess, hf_ipa, array_length(hf_ipa));
+	proto_register_subtree_array(ett, array_length(ett));
+
+	register_dissector("gsm_abis_ip", dissect_abisip, proto_abisip);
+}
+
+void proto_reg_handoff_gsm_abis_ip(void)
+{
+	dissector_handle_t abisip_handle;
+
+	sub_handles[SUB_RSL] = find_dissector("gsm_abis_rsl");
+	sub_handles[SUB_OML] = find_dissector("gsm_abis_oml");
+
+	abisip_handle = create_dissector_handle(dissect_abisip, proto_abisip);
+	dissector_add("tcp.port", TCP_PORT_ABISIP_PRIM, abisip_handle);
+	dissector_add("tcp.port", TCP_PORT_ABISIP_SEC, abisip_handle);
+	dissector_add("tcp.port", TCP_PORT_ABISIP_INST, abisip_handle);
+	dissector_add("udp.port", TCP_PORT_ABISIP_INST, abisip_handle);
+}

-- 
- Harald Welte <laforge@xxxxxxxxxxxx>           http://laforge.gnumonks.org/
============================================================================
"Privacy in residential applications is a desirable marketing option."
                                                  (ETSI EN 300 175-7 Ch. A6)