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/* packet-x29.c
 * Routines for X.29 packet dissection
 *
 * 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

#include "config.h"

#include <epan/packet.h>
#include <epan/nlpid.h>

void proto_register_x29(void);
void proto_reg_handoff_x29(void);

static int proto_x29 = -1;
static int hf_msg_code = -1;
static int hf_error_type = -1;
static int hf_inv_msg_code = -1;

/* Generated from convert_proto_tree_add_text.pl */
static int hf_x29_pad_message_data = -1;
static int hf_x29_type_reference_value = -1;
static int hf_x29_type_reference = -1;
static int hf_x29_data = -1;
static int hf_x29_type_of_aspect = -1;
static int hf_x29_reselection_message_data = -1;
static int hf_x29_break_value = -1;
static int hf_x29_parameter = -1;
static int hf_x29_value = -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 const value_string reference_type_vals[] = {
        { 0x01, "Change in PAD Aspect" },
        { 0x08, "Break" },
        { 0,    NULL },
};

static int
dissect_x29(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data)
{
        int         offset = 0;
        proto_tree *x29_tree;
        proto_item *ti;
        gboolean   *q_bit_set;
        guint8      msg_code;
        guint8      error_type;
        guint8      type_ref;
        gint        next_offset;
        int         linelen;

        /* Reject the packet if data is NULL */
        if (data == NULL)
                return 0;
        q_bit_set = (gboolean *)data;

        col_set_str(pinfo->cinfo, COL_PROTOCOL, "X.29");
        col_clear(pinfo->cinfo, COL_INFO);

        ti = proto_tree_add_item(tree, proto_x29, tvb, offset, -1, ENC_NA);
        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);
                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_item(x29_tree, hf_x29_parameter, tvb, offset, 1, ENC_BIG_ENDIAN);
                                offset++;
                                proto_tree_add_item(x29_tree, hf_x29_value, tvb, offset, 1, ENC_BIG_ENDIAN);
                                offset++;
                        }
                        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, ENC_BIG_ENDIAN);
                        }
                        break;

                case BREAK_IND_MSG:
                        if (tvb_reported_length_remaining(tvb, offset) > 0) {
                                type_ref = tvb_get_guint8(tvb, offset);
                                proto_tree_add_item(x29_tree, hf_x29_type_reference, tvb, offset, 1, ENC_BIG_ENDIAN);
                                offset++;
                                switch (type_ref) {

                                case 0x01:      /* change in PAD Aspect */
                                        /*
                                         * XXX - dissect as per X.28.
                                         */
                                        proto_tree_add_item(x29_tree, hf_x29_type_of_aspect, tvb, offset, 1, ENC_BIG_ENDIAN);
                                        offset++;
                                        break;

                                case 0x08:      /* break */
                                        proto_tree_add_item(x29_tree, hf_x29_break_value, tvb, offset, 1, ENC_BIG_ENDIAN);
                                        offset++;
                                        break;

                                default:
                                        proto_tree_add_item(x29_tree, hf_x29_type_reference_value, tvb, offset, 1, ENC_BIG_ENDIAN);
                                        offset++;
                                        break;
                                }
                        }
                        break;

                case RESELECTION_MSG:
                        /*
                         * XXX - dissect me.
                         */
                        proto_tree_add_item(x29_tree, hf_x29_reselection_message_data, tvb, offset, -1, ENC_NA);
                        break;

                case RESEL_WITH_TOA_NPI_MSG:
                        /*
                         * XXX - dissect me.
                         */
                        proto_tree_add_item(x29_tree, hf_x29_reselection_message_data, tvb, offset, -1, ENC_NA);
                        break;

                default:
                        proto_tree_add_item(x29_tree, hf_x29_pad_message_data, tvb, offset, -1, ENC_NA);
                        break;
                }
        } else {
                /*
                 * Q bit not set - this is data.
                 */
                col_set_str(pinfo->cinfo, COL_INFO, "Data ...");

                if (tree) {
                        while (tvb_offset_exists(tvb, offset)) {
                                /*
                                 * Find the end of the line.
                                 */
                                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_item(x29_tree, hf_x29_data, tvb, offset, linelen, ENC_NA|ENC_ASCII);
                                offset = next_offset;
                        }
                }
        }

        return tvb_captured_length(tvb);
}

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 }},

                /* Generated from convert_proto_tree_add_text.pl */
                { &hf_x29_type_reference, { "Type reference", "x29.type_reference", FT_UINT8, BASE_DEC, VALS(reference_type_vals), 0x0, NULL, HFILL }},
                { &hf_x29_type_of_aspect, { "Type of aspect", "x29.type_of_aspect", FT_UINT8, BASE_HEX, NULL, 0x0, NULL, HFILL }},
                { &hf_x29_break_value, { "Break value", "x29.break_value", FT_UINT8, BASE_HEX, NULL, 0x0, NULL, HFILL }},
                { &hf_x29_type_reference_value, { "Type value", "x29.type_reference.value", FT_UINT8, BASE_HEX, NULL, 0x0, NULL, HFILL }},
                { &hf_x29_reselection_message_data, { "Reselection message data", "x29.reselection_message_data", FT_BYTES, BASE_NONE, NULL, 0x0, NULL, HFILL }},
                { &hf_x29_pad_message_data, { "PAD message data", "x29.pad_message_data", FT_BYTES, BASE_NONE, NULL, 0x0, NULL, HFILL }},
                { &hf_x29_data, { "Data", "x29.data", FT_STRING, BASE_NONE, NULL, 0x0, NULL, HFILL }},
                { &hf_x29_parameter, { "Parameter", "x29.parameter", FT_UINT8, BASE_DEC, NULL, 0x0, NULL, HFILL }},
                { &hf_x29_value, { "Value", "x29.value", FT_UINT8, BASE_DEC, NULL, 0x0, NULL, HFILL }},
        };
        static gint *ett[] = {
                &ett_x29,
        };

        proto_x29 = proto_register_protocol("X.29", "X.29", "x29");
        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_uint("x.25.spi", NLPID_SPI_X_29, x29_handle);
}

/*
 * Editor modelines  -  http://www.wireshark.org/tools/modelines.html
 *
 * Local variables:
 * c-basic-offset: 8
 * tab-width: 8
 * indent-tabs-mode: t
 * End:
 *
 * vi: set shiftwidth=8 tabstop=8 noexpandtab:
 * :indentSize=8:tabSize=8:noTabs=false:
 */