epan/dissectors/packet-x224.c

   1 /* packet-x224.c
   2  *
   3  * Routine to dissect X.224
   4  * Copyright 2007, Ronnie Sahlberg
   5  *
   6  * $Id$
   7  *
   8  * Wireshark - Network traffic analyzer
   9  * By Gerald Combs <gerald@wireshark.org>
  10  * Copyright 1998 Gerald Combs
  11  *
  12  * This program is free software; you can redistribute it and/or
  13  * modify it under the terms of the GNU General Public License
  14  * as published by the Free Software Foundation; either version 2
  15  * of the License, or (at your option) any later version.
  16  *
  17  * This program is distributed in the hope that it will be useful,
  18  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  19  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20  * GNU General Public License for more details.
  21  *
  22  * You should have received a copy of the GNU General Public License
  23  * along with this program; if not, write to the Free Software
  24  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  25  */
  26
  27 #ifdef HAVE_CONFIG_H
  28 # include "config.h"
  29 #endif
  30
  31 #include <glib.h>
  32 #include <epan/packet.h>
  33
  34 #include "packet-tpkt.h"
  35 #include "packet-frame.h"
  36 #include <epan/conversation.h>
  37 #include <epan/prefs.h>
  38 #include <epan/emem.h>
  39
  40 /* X.224 header fields             */
  41 static int proto_x224                   = -1;
  42 static int hf_x224_length               = -1;
  43 static int hf_x224_code                 = -1;
  44 static int hf_x224_src_ref              = -1;
  45 static int hf_x224_dst_ref              = -1;
  46 static int hf_x224_class                = -1;
  47 static int hf_x224_nr                   = -1;
  48 static int hf_x224_eot                  = -1;
  49
  50
  51
  52 /* X.224 fields defining a sub tree */
  53 static gint ett_x224           = -1;
  54
  55
  56 /* find the dissector for T.125 */
  57 static dissector_handle_t t125_handle;
  58
  59
  60 typedef struct _x224_conv_info_t {
  61         guint8  class;
  62 } x224_conv_info_t;
  63
  64
  65 #define X224_CODE_CR            0xE
  66 #define X224_CODE_CC            0xD
  67 #define X224_CODE_DR            0x8
  68 #define X224_CODE_DC            0xC
  69 #define X224_CODE_DT            0xF
  70 #define X224_CODE_ED            0x1
  71 #define X224_CODE_AK            0x6
  72 #define X224_CODE_EA            0x2
  73 #define X224_CODE_RJ            0x5
  74 #define X224_CODE_ER            0x7
  75
  76 static const value_string code_vals[] = {
  77         {X224_CODE_CR,          "Connection Request"},
  78         {X224_CODE_CC,          "Connection Confirm"},
  79         {X224_CODE_DR,          "Disconnect Request"},
  80         {X224_CODE_DC,          "Disconnect Confirm"},
  81         {X224_CODE_DT,          "Data"},
  82         {X224_CODE_ED,          "Expedited Data"},
  83         {X224_CODE_AK,          "Data Ack"},
  84         {X224_CODE_EA,          "Expedited Data Ack"},
  85         {X224_CODE_RJ,          "Reject"},
  86         {X224_CODE_ER,          "Error"},
  87         {0,NULL}
  88 };
  89
  90 static const value_string class_option_vals[] = {
  91         {0,     "Class 0"},
  92         {1,     "Class 1"},
  93         {2,     "Class 2"},
  94         {3,     "Class 3"},
  95         {4,     "Class 4"},
  96         {0,NULL}
  97 };
  98
  99 static int
 100 dissect_x224_cr(packet_info *pinfo _U_, proto_tree *tree, tvbuff_t *tvb, int offset, x224_conv_info_t *x224_info _U_)
 101 {
 102         guint8 class;
 103
 104         /*DST-REF is always 0 */
 105         offset+=2;
 106
 107         /*SRC-REF*/
 108         proto_tree_add_item(tree, hf_x224_src_ref, tvb, offset, 2, FALSE);
 109         offset+=2;
 110
 111         /* class options */
 112         class = tvb_get_guint8(tvb, offset);
 113         proto_tree_add_item(tree, hf_x224_class, tvb, offset, 1, FALSE);
 114         offset+=1;
 115
 116         return offset;
 117 }
 118
 119 static int
 120 dissect_x224_cc(packet_info *pinfo _U_, proto_tree *tree, tvbuff_t *tvb, int offset, x224_conv_info_t *x224_info)
 121 {
 122         guint8 class;
 123
 124         /*DST-REF */
 125         proto_tree_add_item(tree, hf_x224_dst_ref, tvb, offset, 2, FALSE);
 126         offset+=2;
 127
 128         /*SRC-REF*/
 129         proto_tree_add_item(tree, hf_x224_src_ref, tvb, offset, 2, FALSE);
 130         offset+=2;
 131
 132         /* class options */
 133         class = tvb_get_guint8(tvb, offset);
 134         proto_tree_add_item(tree, hf_x224_class, tvb, offset, 1, FALSE);
 135         x224_info->class = class;
 136         offset+=1;
 137
 138         return offset;
 139 }
 140
 141 static int
 142 dissect_x224_dt(packet_info *pinfo _U_, proto_tree *tree, tvbuff_t *tvb, int offset, x224_conv_info_t *x224_info, proto_tree *parent_tree)
 143 {
 144         proto_item *item = NULL;
 145         tvbuff_t *next_tvb;
 146
 147         switch (x224_info->class >>4) {
 148         case 2:
 149         case 3:
 150         case 4:
 151                 /*DST-REF */
 152                 proto_tree_add_item(tree, hf_x224_dst_ref, tvb, offset, 2, FALSE);
 153                 offset+=2;
 154                 break;
 155         }
 156
 157         item = proto_tree_add_uint(tree, hf_x224_class, tvb, 0, 0, x224_info->class);
 158         PROTO_ITEM_SET_GENERATED(item);
 159
 160
 161         /* EOT / NR */
 162         proto_tree_add_item(tree, hf_x224_eot, tvb, offset, 1, FALSE);
 163         proto_tree_add_item(tree, hf_x224_nr, tvb, offset, 1, FALSE);
 164         offset+=1;
 165
 166
 167         next_tvb = tvb_new_subset(tvb, offset, -1, -1);
 168         call_dissector(t125_handle, next_tvb, pinfo, parent_tree);
 169
 170         return offset;
 171 }
 172
 173 static void
 174 dissect_x224(tvbuff_t *tvb, packet_info *pinfo, proto_tree *parent_tree)
 175 {
 176         proto_tree *tree = NULL;
 177         proto_item *item = NULL;
 178         int offset = 0 ;
 179         guint8 code, length;
 180         conversation_t *conversation;
 181         x224_conv_info_t *x224_info;
 182
 183         if (check_col(pinfo->cinfo, COL_PROTOCOL)){
 184                 col_set_str(pinfo->cinfo, COL_PROTOCOL, "X.224");
 185         }
 186         if (check_col(pinfo->cinfo, COL_INFO)){
 187                 col_clear(pinfo->cinfo, COL_INFO);
 188         }
 189
 190         length = tvb_get_guint8(tvb, offset);
 191         if (parent_tree) {
 192                 item = proto_tree_add_item(parent_tree, proto_x224, tvb, offset, length+1, FALSE);
 193                 tree = proto_item_add_subtree(item, ett_x224);
 194         }
 195
 196
 197         /* length indicator */
 198         proto_tree_add_item(tree, hf_x224_length, tvb, offset, 1, FALSE);
 199         offset+=1;
 200
 201         /* code */
 202         code = tvb_get_guint8(tvb, offset);
 203         proto_tree_add_item(tree, hf_x224_code, tvb, offset, 1, FALSE);
 204         offset+=1;
 205
 206         if (check_col(pinfo->cinfo, COL_INFO)) {
 207                 col_add_fstr(pinfo->cinfo, COL_INFO, "%s (0x%02x)",
 208                         val_to_str(code>>4, code_vals, "Unknown code :%x"),
 209                         code);
 210         }
 211
 212
 213
 214         /*
 215          * We need to track some state for this protocol on a per conversation
 216          * basis so we can do neat things like request/response tracking
 217          */
 218         /*
 219          * Do we have a conversation for this connection?
 220          */
 221         conversation = find_conversation(pinfo->fd->num,
 222                                 &pinfo->src, &pinfo->dst,
 223                                 pinfo->ptype,
 224                                 pinfo->srcport, pinfo->destport, 0);
 225         if (conversation == NULL) {
 226                 /* We don't yet have a conversation, so create one. */
 227                 conversation = conversation_new(pinfo->fd->num,
 228                                 &pinfo->src, &pinfo->dst,
 229                                 pinfo->ptype,
 230                                 pinfo->srcport, pinfo->destport, 0);
 231         }
 232         /*
 233          * Do we already have a state structure for this conv
 234          */
 235         x224_info = conversation_get_proto_data(conversation, proto_x224);
 236         if (!x224_info) {
 237                 /* No.  Attach that information to the conversation, and add
 238                  * it to the list of information structures.
 239                  */
 240                 x224_info = se_alloc(sizeof(x224_conv_info_t));
 241                 x224_info->class=0;
 242
 243                 conversation_add_proto_data(conversation, proto_x224, x224_info);
 244        }
 245
 246         switch (code>>4) {
 247         case X224_CODE_CR:
 248                 offset = dissect_x224_cr(pinfo, tree, tvb, offset, x224_info);
 249                 break;
 250         case X224_CODE_CC:
 251                 offset = dissect_x224_cc(pinfo, tree, tvb, offset, x224_info);
 252                 break;
 253         case X224_CODE_DR:
 254                 /* XXX not implemented yet */
 255                 break;
 256         case X224_CODE_DC:
 257                 /* XXX not implemented yet */
 258                 break;
 259         case X224_CODE_DT:
 260                 offset = dissect_x224_dt(pinfo, tree, tvb, offset, x224_info, parent_tree);
 261                 break;
 262         case X224_CODE_ED:
 263                 /* XXX not implemented yet */
 264                 break;
 265         case X224_CODE_AK:
 266                 /* XXX not implemented yet */
 267                 break;
 268         case X224_CODE_EA:
 269                 /* XXX not implemented yet */
 270                 break;
 271         case X224_CODE_RJ:
 272                 /* XXX not implemented yet */
 273                 break;
 274         case X224_CODE_ER:
 275                 /* XXX not implemented yet */
 276                 break;
 277         }
 278 }
 279
 280 void
 281 proto_register_x224(void)
 282 {
 283         static hf_register_info hf[] =
 284         {
 285         { &hf_x224_length, {
 286         "Length", "x224.length", FT_UINT8, BASE_DEC,
 287         NULL, 0, "", HFILL }},
 288
 289         { &hf_x224_code, {
 290         "Code", "x224.code", FT_UINT8, BASE_HEX,
 291         VALS(code_vals), 0xf0, "", HFILL }},
 292
 293         { &hf_x224_src_ref, {
 294         "SRC-REF", "x224.src_ref", FT_UINT16, BASE_HEX,
 295         NULL, 0, "", HFILL }},
 296
 297         { &hf_x224_dst_ref, {
 298         "DST-REF", "x224.dst_ref", FT_UINT16, BASE_HEX,
 299         NULL, 0, "", HFILL }},
 300
 301         { &hf_x224_class, {
 302         "Class", "x224.class", FT_UINT8, BASE_HEX,
 303         VALS(class_option_vals), 0xf0, "", HFILL }},
 304
 305         { &hf_x224_nr, {
 306         "NR", "x224.nr", FT_UINT8, BASE_HEX,
 307         NULL, 0x7f, "", HFILL }},
 308
 309         { &hf_x224_eot, {
 310         "EOT", "x224.eot", FT_BOOLEAN, 8,
 311         NULL, 0x80, "", HFILL }},
 312
 313         };
 314
 315         static gint *ett[] =
 316         {
 317                 &ett_x224,
 318         };
 319
 320         proto_x224 = proto_register_protocol("ITU-T Rec X.224 ", "X.224", "x224");
 321         proto_register_field_array(proto_x224, hf, array_length(hf));
 322         proto_register_subtree_array(ett, array_length(ett));
 323         register_dissector("x224", dissect_x224, proto_x224);
 324
 325 }
 326
 327 void
 328 proto_reg_handoff_x224(void)
 329 {
 330         t125_handle = find_dissector("t125");
 331 }