epan/dissectors/packet-x29.c

   1 /* packet-x29.c
   2  * Routines for X.29 packet dissection
   3  *
   4  * $Id$
   5  *
   6  * Wireshark - Network traffic analyzer
   7  * By Gerald Combs <gerald@wireshark.org>
   8  * Copyright 1998 Gerald Combs
   9  *
  10  * This program is free software; you can redistribute it and/or
  11  * modify it under the terms of the GNU General Public License
  12  * as published by the Free Software Foundation; either version 2
  13  * of the License, or (at your option) any later version.
  14  *
  15  * This program is distributed in the hope that it will be useful,
  16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18  * GNU General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU General Public License
  21  * along with this program; if not, write to the Free Software
  22  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  23  */
  24
  25 #ifdef HAVE_CONFIG_H
  26 # include "config.h"
  27 #endif
  28
  29 #include <stdio.h>
  30
  31 #include <string.h>
  32 #include <glib.h>
  33 #include <epan/packet.h>
  34 #include <epan/strutil.h>
  35 #include <epan/nlpid.h>
  36
  37 static int proto_x29 = -1;
  38 static int hf_msg_code = -1;
  39 static int hf_error_type = -1;
  40 static int hf_inv_msg_code = -1;
  41
  42 static gint ett_x29 = -1;
  43
  44 /*
  45  * PAD messages.
  46  */
  47 #define SET_MSG                 0x02
  48 #define READ_MSG                0x04
  49 #define SET_AND_READ_MSG        0x06
  50 #define PARAMETER_IND_MSG       0x00
  51 #define INV_TO_CLEAR_MSG        0x01
  52 #define BREAK_IND_MSG           0x03
  53 #define RESELECTION_MSG         0x07
  54 #define ERROR_MSG               0x05
  55 #define RESEL_WITH_TOA_NPI_MSG  0x08
  56
  57 static const value_string message_code_vals[] = {
  58         { SET_MSG,                      "Set" },
  59         { READ_MSG,                     "Read" },
  60         { SET_AND_READ_MSG,             "Set and read" },
  61         { PARAMETER_IND_MSG,            "Parameter indication" },
  62         { INV_TO_CLEAR_MSG,             "Invitation to clear" },
  63         { BREAK_IND_MSG,                "Indication of break" },
  64         { RESELECTION_MSG,              "Reselection" },
  65         { ERROR_MSG,                    "Error" },
  66         { RESEL_WITH_TOA_NPI_MSG,       "Reselection with TOA/NPI" },
  67         { 0,                            NULL }
  68 };
  69
  70 static const value_string error_type_vals[] = {
  71         { 0x00, "Received PAD message contained less than eight bits" },
  72         { 0x02, "Unrecognized message code in received PAD message" },
  73         { 0x04, "Parameter field format was incorrect or incompatible with message code" },
  74         { 0x06, "Received PAD message did not contain an integral number of octets" },
  75         { 0x08, "Received Parameter Indication PAD message was unsolicited" },
  76         { 0x0A, "Received PAD message was too long" },
  77         { 0x0C, "Unauthorized reselection PAD message" },
  78         { 0,    NULL },
  79 };
  80
  81 static void
  82 dissect_x29(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
  83 {
  84         int offset = 0;
  85         proto_tree *x29_tree = NULL;
  86         proto_item *ti;
  87         gboolean *q_bit_set = pinfo->private_data;
  88         guint8 msg_code;
  89         guint8 error_type;
  90         guint8 type_ref;
  91         gint next_offset;
  92         int linelen;
  93
  94         col_set_str(pinfo->cinfo, COL_PROTOCOL, "X.29");
  95         if (check_col(pinfo->cinfo, COL_INFO))
  96                 col_clear(pinfo->cinfo, COL_INFO);
  97
  98         if (tree) {
  99                 ti = proto_tree_add_item(tree, proto_x29, tvb, offset, -1,
 100                     FALSE);
 101                 x29_tree = proto_item_add_subtree(ti, ett_x29);
 102         }
 103
 104         if (*q_bit_set) {
 105                 /*
 106                  * Q bit set - this is a PAD message.
 107                  */
 108                 msg_code = tvb_get_guint8(tvb, offset);
 109                 if (check_col(pinfo->cinfo, COL_INFO)) {
 110                         col_add_fstr(pinfo->cinfo, COL_INFO, "%s PAD message",
 111                             val_to_str(msg_code, message_code_vals,
 112                                 "Unknown (0x%02x)"));
 113                 }
 114                 proto_tree_add_uint(x29_tree, hf_msg_code, tvb,
 115                     offset, 1, msg_code);
 116                 offset++;
 117
 118                 switch (msg_code) {
 119
 120                 case SET_MSG:
 121                 case READ_MSG:
 122                 case SET_AND_READ_MSG:
 123                 case PARAMETER_IND_MSG:
 124                         /*
 125                          * XXX - dissect the references as per X.3.
 126                          */
 127                         while (tvb_reported_length_remaining(tvb, offset) > 0) {
 128                                 proto_tree_add_text(x29_tree, tvb, offset, 2,
 129                                     "Parameter %u, value %u",
 130                                     tvb_get_guint8(tvb, offset),
 131                                     tvb_get_guint8(tvb, offset + 1));
 132                                 offset += 2;
 133                         }
 134                         break;
 135
 136                 case INV_TO_CLEAR_MSG:
 137                         /*
 138                          * No data for this message.
 139                          */
 140                         break;
 141
 142                 case ERROR_MSG:
 143                         error_type = tvb_get_guint8(tvb, offset);
 144                         proto_tree_add_uint(x29_tree, hf_error_type, tvb,
 145                             offset, 1, error_type);
 146                         offset++;
 147                         if (error_type != 0) {
 148                                 proto_tree_add_item(x29_tree, hf_inv_msg_code,
 149                                     tvb, offset, 1, FALSE);
 150                         }
 151                         break;
 152
 153                 case BREAK_IND_MSG:
 154                         if (tvb_reported_length_remaining(tvb, offset) > 0) {
 155                                 type_ref = tvb_get_guint8(tvb, offset);
 156                                 switch (type_ref) {
 157
 158                                 case 0x01:      /* change in PAD Aspect */
 159                                         /*
 160                                          * XXX - dissect as per X.28.
 161                                          */
 162                                         proto_tree_add_text(x29_tree, tvb,
 163                                             offset, 1, "Type reference: Change in PAD Aspect");
 164                                         offset++;
 165                                         proto_tree_add_text(x29_tree, tvb,
 166                                             offset, 1, "Type of aspect: 0x%02x",
 167                                             type_ref);
 168                                         offset++;
 169                                         break;
 170
 171                                 case 0x08:      /* break */
 172                                         proto_tree_add_text(x29_tree, tvb,
 173                                             offset, 1, "Type reference: Break");
 174                                         offset++;
 175                                         proto_tree_add_text(x29_tree, tvb,
 176                                             offset, 1, "Break value: 0x%02x",
 177                                             type_ref);
 178                                         offset++;
 179                                         break;
 180
 181                                 default:
 182                                         proto_tree_add_text(x29_tree, tvb,
 183                                             offset, 1, "Unknown type reference (0x%02x)",
 184                                             type_ref);
 185                                         offset++;
 186                                         proto_tree_add_text(x29_tree, tvb,
 187                                             offset, 1, "Type value: 0x%02x",
 188                                             type_ref);
 189                                         offset++;
 190                                         break;
 191                                 }
 192                         }
 193                         break;
 194
 195                 case RESELECTION_MSG:
 196                         /*
 197                          * XXX - dissect me.
 198                          */
 199                         proto_tree_add_text(x29_tree, tvb, offset, -1,
 200                             "Reselection message data");
 201                         break;
 202
 203                 case RESEL_WITH_TOA_NPI_MSG:
 204                         /*
 205                          * XXX - dissect me.
 206                          */
 207                         proto_tree_add_text(x29_tree, tvb, offset, -1,
 208                             "Reselection message data");
 209                         break;
 210
 211                 default:
 212                         proto_tree_add_text(x29_tree, tvb, offset, -1,
 213                             "PAD message data");
 214                         break;
 215                 }
 216         } else {
 217                 /*
 218                  * Q bit not set - this is data.
 219                  */
 220                 if (check_col(pinfo->cinfo, COL_INFO))
 221                         col_set_str(pinfo->cinfo, COL_INFO, "Data ...");
 222
 223                 if (tree) {
 224                         while (tvb_offset_exists(tvb, offset)) {
 225                                 /*
 226                                  * Find the end of the line.
 227                                  */
 228                                 linelen = tvb_find_line_end(tvb, offset, -1,
 229                                     &next_offset, FALSE);
 230
 231                                 /*
 232                                  * Now compute the length of the line
 233                                  * *including* the end-of-line indication,
 234                                  * if any; we display it all.
 235                                  */
 236                                 linelen = next_offset - offset;
 237
 238                                 proto_tree_add_text(x29_tree, tvb, offset,
 239                                     linelen, "Data: %s",
 240                                     tvb_format_text(tvb, offset, linelen));
 241                                 offset = next_offset;
 242                         }
 243                 }
 244         }
 245 }
 246
 247 void
 248 proto_register_x29(void)
 249 {
 250         static hf_register_info hf[] = {
 251             { &hf_msg_code,
 252                 { "Message code", "x29.msg_code", FT_UINT8, BASE_HEX,
 253                   VALS(message_code_vals), 0x0, "X.29 PAD message code",
 254                   HFILL }},
 255             { &hf_error_type,
 256                 { "Error type", "x29.error_type", FT_UINT8, BASE_HEX,
 257                   VALS(error_type_vals), 0x0, "X.29 error PAD message error type",
 258                   HFILL }},
 259             { &hf_inv_msg_code,
 260                 { "Invalid message code", "x29.inv_msg_code", FT_UINT8, BASE_HEX,
 261                   VALS(message_code_vals), 0x0, "X.29 Error PAD message invalid message code",
 262                   HFILL }},
 263         };
 264         static gint *ett[] = {
 265                 &ett_x29,
 266         };
 267
 268         proto_x29 = proto_register_protocol("X.29", "X.29", "x29");
 269         proto_register_field_array(proto_x29, hf, array_length(hf));
 270         proto_register_subtree_array(ett, array_length(ett));
 271 }
 272
 273 void
 274 proto_reg_handoff_x29(void)
 275 {
 276         dissector_handle_t x29_handle;
 277
 278         x29_handle = create_dissector_handle(dissect_x29, proto_x29);
 279         dissector_add("x.25.spi", NLPID_SPI_X_29, x29_handle);
 280 }