packet-x29.c

   1 /* packet-x29.c
   2  * Routines for X.29 packet dissection
   3  *
   4  * $Id: packet-x29.c,v 1.1 2003/01/06 02:24:57 guy Exp $
   5  *
   6  * Ethereal - Network traffic analyzer
   7  * By Gerald Combs <gerald@ethereal.com>
   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 "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         if (check_col(pinfo->cinfo, COL_PROTOCOL))
  95                 col_set_str(pinfo->cinfo, COL_PROTOCOL, "X.29");
  96         if (check_col(pinfo->cinfo, COL_INFO))
  97                 col_clear(pinfo->cinfo, COL_INFO);
  98
  99         if (tree) {
 100                 ti = proto_tree_add_item(tree, proto_x29, tvb, offset, -1,
 101                     FALSE);
 102                 x29_tree = proto_item_add_subtree(ti, ett_x29);
 103         }
 104
 105         if (*q_bit_set) {
 106                 /*
 107                  * Q bit set - this is a PAD message.
 108                  */
 109                 msg_code = tvb_get_guint8(tvb, offset);
 110                 if (check_col(pinfo->cinfo, COL_INFO)) {
 111                         col_add_fstr(pinfo->cinfo, COL_INFO, "%s PAD message",
 112                             val_to_str(msg_code, message_code_vals,
 113                                 "Unknown (0x%02x)"));
 114                 }
 115                 proto_tree_add_uint(x29_tree, hf_msg_code, tvb,
 116                     offset, 1, msg_code);
 117                 offset++;
 118
 119                 switch (msg_code) {
 120
 121                 case SET_MSG:
 122                 case READ_MSG:
 123                 case SET_AND_READ_MSG:
 124                 case PARAMETER_IND_MSG:
 125                         /*
 126                          * XXX - dissect the references as per X.3.
 127                          */
 128                         while (tvb_reported_length_remaining(tvb, offset) > 0) {
 129                                 proto_tree_add_text(x29_tree, tvb, offset, 2,
 130                                     "Parameter %u, value %u",
 131                                     tvb_get_guint8(tvb, offset),
 132                                     tvb_get_guint8(tvb, offset + 1));
 133                                 offset += 2;
 134                         }
 135                         break;
 136
 137                 case INV_TO_CLEAR_MSG:
 138                         /*
 139                          * No data for this message.
 140                          */
 141                         break;
 142
 143                 case ERROR_MSG:
 144                         error_type = tvb_get_guint8(tvb, offset);
 145                         proto_tree_add_uint(x29_tree, hf_error_type, tvb,
 146                             offset, 1, error_type);
 147                         offset++;
 148                         if (error_type != 0) {
 149                                 proto_tree_add_item(x29_tree, hf_inv_msg_code,
 150                                     tvb, offset, 1, FALSE);
 151                         }
 152                         break;
 153
 154                 case BREAK_IND_MSG:
 155                         if (tvb_reported_length_remaining(tvb, offset) > 0) {
 156                                 type_ref = tvb_get_guint8(tvb, offset);
 157                                 switch (type_ref) {
 158
 159                                 case 0x01:      /* change in PAD Aspect */
 160                                         /*
 161                                          * XXX - dissect as per X.28.
 162                                          */
 163                                         proto_tree_add_text(x29_tree, tvb,
 164                                             offset, 1, "Type reference: Change in PAD Aspect");
 165                                         offset++;
 166                                         proto_tree_add_text(x29_tree, tvb,
 167                                             offset, 1, "Type of aspect: 0x%02x",
 168                                             type_ref);
 169                                         offset++;
 170                                         break;
 171
 172                                 case 0x08:      /* break */
 173                                         proto_tree_add_text(x29_tree, tvb,
 174                                             offset, 1, "Type reference: Break");
 175                                         offset++;
 176                                         proto_tree_add_text(x29_tree, tvb,
 177                                             offset, 1, "Break value: 0x%02x",
 178                                             type_ref);
 179                                         offset++;
 180                                         break;
 181
 182                                 default:
 183                                         proto_tree_add_text(x29_tree, tvb,
 184                                             offset, 1, "Unknown type reference (0x%02x)",
 185                                             type_ref);
 186                                         offset++;
 187                                         proto_tree_add_text(x29_tree, tvb,
 188                                             offset, 1, "Type value: 0x%02x",
 189                                             type_ref);
 190                                         offset++;
 191                                         break;
 192                                 }
 193                         }
 194                         break;
 195
 196                 case RESELECTION_MSG:
 197                         /*
 198                          * XXX - dissect me.
 199                          */
 200                         proto_tree_add_text(x29_tree, tvb, offset, -1,
 201                             "Reselection message data");
 202                         break;
 203
 204                 case RESEL_WITH_TOA_NPI_MSG:
 205                         /*
 206                          * XXX - dissect me.
 207                          */
 208                         proto_tree_add_text(x29_tree, tvb, offset, -1,
 209                             "Reselection message data");
 210                         break;
 211
 212                 default:
 213                         proto_tree_add_text(x29_tree, tvb, offset, -1,
 214                             "PAD message data");
 215                         break;
 216                 }
 217         } else {
 218                 /*
 219                  * Q bit not set - this is data.
 220                  */
 221                 if (check_col(pinfo->cinfo, COL_INFO))
 222                         col_add_fstr(pinfo->cinfo, COL_INFO, "Data ...");
 223
 224                 if (tree) {
 225                         while (tvb_offset_exists(tvb, offset)) {
 226                                 /*
 227                                  * Find the end of the line.
 228                                  */
 229                                 linelen = tvb_find_line_end(tvb, offset, -1,
 230                                     &next_offset, FALSE);
 231
 232                                 /*
 233                                  * Now compute the length of the line
 234                                  * *including* the end-of-line indication,
 235                                  * if any; we display it all.
 236                                  */
 237                                 linelen = next_offset - offset;
 238
 239                                 proto_tree_add_text(x29_tree, tvb, offset,
 240                                     linelen, "Data: %s",
 241                                     tvb_format_text(tvb, offset, linelen));
 242                                 offset = next_offset;
 243                         }
 244                 }
 245         }
 246 }
 247
 248 void
 249 proto_register_x29(void)
 250 {
 251         static hf_register_info hf[] = {
 252             { &hf_msg_code,
 253                 { "Message code", "x29.msg_code", FT_UINT8, BASE_HEX,
 254                   VALS(message_code_vals), 0x0, "X.29 PAD message code",
 255                   HFILL }},
 256             { &hf_error_type,
 257                 { "Error type", "x29.error_type", FT_UINT8, BASE_HEX,
 258                   VALS(error_type_vals), 0x0, "X.29 error PAD message error type",
 259                   HFILL }},
 260             { &hf_inv_msg_code,
 261                 { "Invalid message code", "x29.inv_msg_code", FT_UINT8, BASE_HEX,
 262                   VALS(message_code_vals), 0x0, "X.29 Error PAD message invalid message code",
 263                   HFILL }},
 264         };
 265         static gint *ett[] = {
 266                 &ett_x29,
 267         };
 268
 269         proto_x29 = proto_register_protocol("X.29", "X.29", "x.29");
 270         proto_register_field_array(proto_x29, hf, array_length(hf));
 271         proto_register_subtree_array(ett, array_length(ett));
 272 }
 273
 274 void
 275 proto_reg_handoff_x29(void)
 276 {
 277         dissector_handle_t x29_handle;
 278
 279         x29_handle = create_dissector_handle(dissect_x29, proto_x29);
 280         dissector_add("x.25.spi", NLPID_SPI_X_29, x29_handle);
 281 }