Add an X.29 dissector.

The Q bit in X.25 doesn't mean "this is QLLC traffic", it's just a "this
packet is special" indication.  Have the X.25 dissector pass as the
"private_data" pointer a pointer to a gboolean indicating whether the Q
bit was set or not.  Replace the "decode non-Q-bit traffic as SNA"
option with a "decode traffic as QLLC/SNA if we didn't see the Call
Request packet and thus don't know what it is" option, which hands
traffic to the QLLC dissector for that traffic.  Have the QLLC dissector
hand traffic to the SNA dissector if the Q bit isn't set.

Arrange that we determine whether the Q bit is set regardless of whether
we're building the protocol tree or not.

If we don't just dissect traffic as QLLC/SNA if we didn't see the Call
Request packet, check not only for 0x45 (as an indication that it's
probably IP), check also for NLPID_ISO8473_CLNP and treat that as an
indication that it's probably OSI CLNP.


git-svn-id: http://anonsvn.wireshark.org/wireshark/trunk@6854 f5534014-38df-0310-8fa8-9805f1628bb7

1 files changed, 281 insertions, 0 deletions

diff --git a/packet-x29.c b/packet-x29.c
new file mode 100644
index 0000000000..49afb898be
--- /dev/null
+++ b/packet-x29.c
@@ -0,0 +1,281 @@
+/* packet-x29.c
+ * Routines for X.29 packet dissection
+ *
+ * $Id: packet-x29.c,v 1.1 2003/01/06 02:24:57 guy Exp $
+ *
+ * Ethereal - Network traffic analyzer
+ * By Gerald Combs <gerald@ethereal.com>
+ * 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 <stdio.h>
+
+#include <string.h>
+#include <glib.h>
+#include <epan/packet.h>
+#include <epan/strutil.h>
+#include "nlpid.h"
+
+static int proto_x29 = -1;
+static int hf_msg_code = -1;
+static int hf_error_type = -1;
+static int hf_inv_msg_code = -1;
+
+static gint ett_x29 = -1;
+
+/*
+ * PAD messages.
+ */
+#define SET_MSG			0x02
+#define READ_MSG		0x04
+#define SET_AND_READ_MSG	0x06
+#define PARAMETER_IND_MSG	0x00
+#define INV_TO_CLEAR_MSG	0x01
+#define BREAK_IND_MSG		0x03
+#define RESELECTION_MSG		0x07
+#define ERROR_MSG		0x05
+#define RESEL_WITH_TOA_NPI_MSG	0x08
+
+static const value_string message_code_vals[] = {
+	{ SET_MSG,			"Set" },
+	{ READ_MSG,			"Read" },
+	{ SET_AND_READ_MSG,		"Set and read" },
+	{ PARAMETER_IND_MSG,		"Parameter indication" },
+	{ INV_TO_CLEAR_MSG,		"Invitation to clear" },
+	{ BREAK_IND_MSG,		"Indication of break" },
+	{ RESELECTION_MSG,		"Reselection" },
+	{ ERROR_MSG,			"Error" },
+	{ RESEL_WITH_TOA_NPI_MSG,	"Reselection with TOA/NPI" },
+	{ 0,				NULL }
+};
+
+static const value_string error_type_vals[] = {
+	{ 0x00, "Received PAD message contained less than eight bits" },
+	{ 0x02, "Unrecognized message code in received PAD message" },
+	{ 0x04, "Parameter field format was incorrect or incompatible with message code" },
+	{ 0x06, "Received PAD message did not contain an integral number of octets" },
+	{ 0x08, "Received Parameter Indication PAD message was unsolicited" },
+	{ 0x0A, "Received PAD message was too long" },
+	{ 0x0C, "Unauthorized reselection PAD message" },
+	{ 0,    NULL },
+};
+
+static void
+dissect_x29(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
+{
+	int offset = 0;
+        proto_tree *x29_tree = NULL;
+        proto_item *ti;
+	gboolean *q_bit_set = pinfo->private_data;
+	guint8 msg_code;
+	guint8 error_type;
+	guint8 type_ref;
+	gint next_offset;
+	int linelen;
+
+	if (check_col(pinfo->cinfo, COL_PROTOCOL))
+		col_set_str(pinfo->cinfo, COL_PROTOCOL, "X.29");
+	if (check_col(pinfo->cinfo, COL_INFO))
+		col_clear(pinfo->cinfo, COL_INFO);
+
+	if (tree) {
+		ti = proto_tree_add_item(tree, proto_x29, tvb, offset, -1,
+		    FALSE);
+		x29_tree = proto_item_add_subtree(ti, ett_x29);
+	}
+
+	if (*q_bit_set) {
+		/*
+		 * Q bit set - this is a PAD message.
+		 */
+		msg_code = tvb_get_guint8(tvb, offset);
+		if (check_col(pinfo->cinfo, COL_INFO)) {
+			col_add_fstr(pinfo->cinfo, COL_INFO, "%s PAD message",
+			    val_to_str(msg_code, message_code_vals,
+			        "Unknown (0x%02x)"));
+		}
+		proto_tree_add_uint(x29_tree, hf_msg_code, tvb,
+		    offset, 1, msg_code);
+		offset++;
+
+		switch (msg_code) {
+
+		case SET_MSG:
+		case READ_MSG:
+		case SET_AND_READ_MSG:
+		case PARAMETER_IND_MSG:
+			/*
+			 * XXX - dissect the references as per X.3.
+			 */
+			while (tvb_reported_length_remaining(tvb, offset) > 0) {
+				proto_tree_add_text(x29_tree, tvb, offset, 2,
+				    "Parameter %u, value %u",
+				    tvb_get_guint8(tvb, offset),
+				    tvb_get_guint8(tvb, offset + 1));
+				offset += 2;
+			}
+			break;
+
+		case INV_TO_CLEAR_MSG:
+			/*
+			 * No data for this message.
+			 */
+			break;
+
+		case ERROR_MSG:
+			error_type = tvb_get_guint8(tvb, offset);
+			proto_tree_add_uint(x29_tree, hf_error_type, tvb,
+			    offset, 1, error_type);
+			offset++;
+			if (error_type != 0) {
+				proto_tree_add_item(x29_tree, hf_inv_msg_code,
+				    tvb, offset, 1, FALSE);
+			}
+			break;
+
+		case BREAK_IND_MSG:
+			if (tvb_reported_length_remaining(tvb, offset) > 0) {
+				type_ref = tvb_get_guint8(tvb, offset);
+				switch (type_ref) {
+
+				case 0x01:	/* change in PAD Aspect */
+					/*
+					 * XXX - dissect as per X.28.
+					 */
+					proto_tree_add_text(x29_tree, tvb,
+					    offset, 1, "Type reference: Change in PAD Aspect");
+					offset++;
+					proto_tree_add_text(x29_tree, tvb,
+					    offset, 1, "Type of aspect: 0x%02x",
+					    type_ref);
+					offset++;
+					break;
+
+				case 0x08:	/* break */
+					proto_tree_add_text(x29_tree, tvb,
+					    offset, 1, "Type reference: Break");
+					offset++;
+					proto_tree_add_text(x29_tree, tvb,
+					    offset, 1, "Break value: 0x%02x",
+					    type_ref);
+					offset++;
+					break;
+
+				default:
+					proto_tree_add_text(x29_tree, tvb,
+					    offset, 1, "Unknown type reference (0x%02x)",
+					    type_ref);
+					offset++;
+					proto_tree_add_text(x29_tree, tvb,
+					    offset, 1, "Type value: 0x%02x",
+					    type_ref);
+					offset++;
+					break;
+				}
+			}
+			break;
+
+		case RESELECTION_MSG:
+			/*
+			 * XXX - dissect me.
+			 */
+			proto_tree_add_text(x29_tree, tvb, offset, -1,
+			    "Reselection message data");
+			break;
+
+		case RESEL_WITH_TOA_NPI_MSG:
+			/*
+			 * XXX - dissect me.
+			 */
+			proto_tree_add_text(x29_tree, tvb, offset, -1,
+			    "Reselection message data");
+			break;
+
+		default:
+			proto_tree_add_text(x29_tree, tvb, offset, -1,
+			    "PAD message data");
+			break;
+		}
+	} else {
+		/*
+		 * Q bit not set - this is data.
+		 */
+		if (check_col(pinfo->cinfo, COL_INFO))
+			col_add_fstr(pinfo->cinfo, COL_INFO, "Data ...");
+
+		if (tree) {
+			while (tvb_offset_exists(tvb, offset)) {
+				/*
+				 * Find the end of the line.
+				 */
+				linelen = tvb_find_line_end(tvb, offset, -1,
+				    &next_offset, FALSE);
+
+				/*
+				 * Now compute the length of the line
+				 * *including* the end-of-line indication,
+				 * if any; we display it all.
+				 */
+				linelen = next_offset - offset;
+
+				proto_tree_add_text(x29_tree, tvb, offset,
+				    linelen, "Data: %s",
+				    tvb_format_text(tvb, offset, linelen));
+				offset = next_offset;
+			}
+		}
+	}
+}
+
+void
+proto_register_x29(void)
+{
+	static hf_register_info hf[] = {
+	    { &hf_msg_code,
+		{ "Message code", "x29.msg_code", FT_UINT8, BASE_HEX,
+		  VALS(message_code_vals), 0x0, "X.29 PAD message code",
+		  HFILL }},
+	    { &hf_error_type,
+		{ "Error type", "x29.error_type", FT_UINT8, BASE_HEX,
+		  VALS(error_type_vals), 0x0, "X.29 error PAD message error type",
+		  HFILL }},
+	    { &hf_inv_msg_code,
+		{ "Invalid message code", "x29.inv_msg_code", FT_UINT8, BASE_HEX,
+		  VALS(message_code_vals), 0x0, "X.29 Error PAD message invalid message code",
+		  HFILL }},
+        };
+	static gint *ett[] = {
+		&ett_x29,
+	};
+
+        proto_x29 = proto_register_protocol("X.29", "X.29", "x.29");
+	proto_register_field_array(proto_x29, hf, array_length(hf));
+	proto_register_subtree_array(ett, array_length(ett));
+}
+
+void
+proto_reg_handoff_x29(void)
+{
+	dissector_handle_t x29_handle;
+
+	x29_handle = create_dissector_handle(dissect_x29, proto_x29);
+	dissector_add("x.25.spi", NLPID_SPI_X_29, x29_handle);
+}