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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  25  */
  26
  27 #include "config.h"
  28
  29 #include <glib.h>
  30 #include <epan/packet.h>
  31
  32 #include "packet-tpkt.h"
  33 #include "packet-frame.h"
  34 #include <epan/conversation.h>
  35 #include <epan/emem.h>
  36
  37 /* X.224 header fields             */
  38 static int proto_x224                   = -1;
  39 static int hf_x224_length               = -1;
  40 static int hf_x224_code                 = -1;
  41 static int hf_x224_src_ref              = -1;
  42 static int hf_x224_dst_ref              = -1;
  43 static int hf_x224_class                = -1;
  44 static int hf_x224_rdp_rt               = -1;
  45 static int hf_x224_nr                   = -1;
  46 static int hf_x224_eot                  = -1;
  47
  48
  49
  50 /* X.224 fields defining a sub tree */
  51 static gint ett_x224           = -1;
  52
  53
  54 /* find the dissector for T.125 */
  55 static dissector_handle_t t125_handle;
  56
  57
  58 typedef struct _x224_conv_info_t {
  59         guint8  class;
  60 } x224_conv_info_t;
  61
  62
  63 #define X224_CODE_CR            0xE
  64 #define X224_CODE_CC            0xD
  65 #define X224_CODE_DR            0x8
  66 #define X224_CODE_DC            0xC
  67 #define X224_CODE_DT            0xF
  68 #define X224_CODE_ED            0x1
  69 #define X224_CODE_AK            0x6
  70 #define X224_CODE_EA            0x2
  71 #define X224_CODE_RJ            0x5
  72 #define X224_CODE_ER            0x7
  73
  74 static const value_string code_vals[] = {
  75         {X224_CODE_CR,          "Connection Request"},
  76         {X224_CODE_CC,          "Connection Confirm"},
  77         {X224_CODE_DR,          "Disconnect Request"},
  78         {X224_CODE_DC,          "Disconnect Confirm"},
  79         {X224_CODE_DT,          "Data"},
  80         {X224_CODE_ED,          "Expedited Data"},
  81         {X224_CODE_AK,          "Data Ack"},
  82         {X224_CODE_EA,          "Expedited Data Ack"},
  83         {X224_CODE_RJ,          "Reject"},
  84         {X224_CODE_ER,          "Error"},
  85         {0,NULL}
  86 };
  87
  88 static const value_string class_option_vals[] = {
  89         {0,     "Class 0"},
  90         {1,     "Class 1"},
  91         {2,     "Class 2"},
  92         {3,     "Class 3"},
  93         {4,     "Class 4"},
  94         {0,NULL}
  95 };
  96
  97 static int
  98 dissect_x224_cr(packet_info *pinfo _U_, proto_tree *tree, tvbuff_t *tvb, int offset, x224_conv_info_t *x224_info _U_)
  99 {
 100         /*guint8 class;*/
 101         gint len, next_offset;
 102
 103         /*DST-REF is always 0 */
 104         offset+=2;
 105
 106         /*SRC-REF*/
 107         proto_tree_add_item(tree, hf_x224_src_ref, tvb, offset, 2, ENC_BIG_ENDIAN);
 108         offset+=2;
 109
 110         /* class options */
 111         /*class = tvb_get_guint8(tvb, offset);*/
 112         proto_tree_add_item(tree, hf_x224_class, tvb, offset, 1, ENC_BIG_ENDIAN);
 113         offset+=1;
 114
 115         if(tvb_length_remaining(tvb, offset) > 0) {
 116                 len = tvb_find_line_end(tvb, offset, -1, &next_offset, TRUE);
 117                 proto_tree_add_item(tree, hf_x224_rdp_rt, tvb, offset, len,
 118                                     ENC_ASCII|ENC_NA);
 119                 offset = next_offset;
 120         }
 121
 122         return offset;
 123 }
 124
 125 static int
 126 dissect_x224_cc(packet_info *pinfo _U_, proto_tree *tree, tvbuff_t *tvb, int offset, x224_conv_info_t *x224_info)
 127 {
 128         guint8 class;
 129
 130         /*DST-REF */
 131         proto_tree_add_item(tree, hf_x224_dst_ref, tvb, offset, 2, ENC_BIG_ENDIAN);
 132         offset+=2;
 133
 134         /*SRC-REF*/
 135         proto_tree_add_item(tree, hf_x224_src_ref, tvb, offset, 2, ENC_BIG_ENDIAN);
 136         offset+=2;
 137
 138         /* class options */
 139         class = tvb_get_guint8(tvb, offset);
 140         proto_tree_add_item(tree, hf_x224_class, tvb, offset, 1, ENC_BIG_ENDIAN);
 141         x224_info->class = class;
 142         offset+=1;
 143
 144         return offset;
 145 }
 146
 147 static int
 148 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)
 149 {
 150         proto_item *item = NULL;
 151         tvbuff_t *next_tvb;
 152
 153         switch (x224_info->class >>4) {
 154         case 2:
 155         case 3:
 156         case 4:
 157                 /*DST-REF */
 158                 proto_tree_add_item(tree, hf_x224_dst_ref, tvb, offset, 2, ENC_BIG_ENDIAN);
 159                 offset+=2;
 160                 break;
 161         }
 162
 163         item = proto_tree_add_uint(tree, hf_x224_class, tvb, 0, 0, x224_info->class);
 164         PROTO_ITEM_SET_GENERATED(item);
 165
 166
 167         /* EOT / NR */
 168         proto_tree_add_item(tree, hf_x224_eot, tvb, offset, 1, ENC_BIG_ENDIAN);
 169         proto_tree_add_item(tree, hf_x224_nr, tvb, offset, 1, ENC_BIG_ENDIAN);
 170         offset+=1;
 171
 172
 173         next_tvb = tvb_new_subset_remaining(tvb, offset);
 174         call_dissector(t125_handle, next_tvb, pinfo, parent_tree);
 175
 176         return offset;
 177 }
 178
 179 static int
 180 dissect_x224(tvbuff_t *tvb, packet_info *pinfo, proto_tree *parent_tree, void *data _U_)
 181 {
 182         proto_tree *tree = NULL;
 183         proto_item *item = NULL;
 184         int offset = 0 ;
 185         guint8 code, length;
 186         conversation_t *conversation;
 187         x224_conv_info_t *x224_info;
 188
 189         col_set_str(pinfo->cinfo, COL_PROTOCOL, "X.224");
 190         col_clear(pinfo->cinfo, COL_INFO);
 191
 192         length = tvb_get_guint8(tvb, offset);
 193         if (parent_tree) {
 194                 item = proto_tree_add_item(parent_tree, proto_x224, tvb, offset, length+1, ENC_NA);
 195                 tree = proto_item_add_subtree(item, ett_x224);
 196         }
 197
 198
 199         /* length indicator */
 200         proto_tree_add_item(tree, hf_x224_length, tvb, offset, 1, ENC_BIG_ENDIAN);
 201         offset+=1;
 202
 203         /* code */
 204         code = tvb_get_guint8(tvb, offset);
 205         proto_tree_add_item(tree, hf_x224_code, tvb, offset, 1, ENC_BIG_ENDIAN);
 206         offset+=1;
 207
 208         if (check_col(pinfo->cinfo, COL_INFO)) {
 209                 col_add_fstr(pinfo->cinfo, COL_INFO, "%s (0x%02x)",
 210                         val_to_str(code>>4, code_vals, "Unknown code :%x"),
 211                         code);
 212         }
 213
 214
 215
 216         /*
 217          * We need to track some state for this protocol on a per conversation
 218          * basis so we can do neat things like request/response tracking
 219          */
 220         conversation = find_or_create_conversation(pinfo);
 221
 222         /*
 223          * Do we already have a state structure for this conv
 224          */
 225         x224_info = conversation_get_proto_data(conversation, proto_x224);
 226         if (!x224_info) {
 227                 /* No.  Attach that information to the conversation, and add
 228                  * it to the list of information structures.
 229                  */
 230                 x224_info = se_alloc(sizeof(x224_conv_info_t));
 231                 x224_info->class=0;
 232
 233                 conversation_add_proto_data(conversation, proto_x224, x224_info);
 234        }
 235
 236         switch (code>>4) {
 237         case X224_CODE_CR:
 238                 offset = dissect_x224_cr(pinfo, tree, tvb, offset, x224_info);
 239                 break;
 240         case X224_CODE_CC:
 241                 offset = dissect_x224_cc(pinfo, tree, tvb, offset, x224_info);
 242                 break;
 243         case X224_CODE_DR:
 244                 /* XXX not implemented yet */
 245                 break;
 246         case X224_CODE_DC:
 247                 /* XXX not implemented yet */
 248                 break;
 249         case X224_CODE_DT:
 250                 offset = dissect_x224_dt(pinfo, tree, tvb, offset, x224_info, parent_tree);
 251                 break;
 252         case X224_CODE_ED:
 253                 /* XXX not implemented yet */
 254                 break;
 255         case X224_CODE_AK:
 256                 /* XXX not implemented yet */
 257                 break;
 258         case X224_CODE_EA:
 259                 /* XXX not implemented yet */
 260                 break;
 261         case X224_CODE_RJ:
 262                 /* XXX not implemented yet */
 263                 break;
 264         case X224_CODE_ER:
 265                 /* XXX not implemented yet */
 266                 break;
 267         }
 268 return offset;
 269 }
 270
 271 void
 272 proto_register_x224(void)
 273 {
 274         static hf_register_info hf[] =
 275         {
 276         { &hf_x224_length, {
 277         "Length", "x224.length", FT_UINT8, BASE_DEC,
 278         NULL, 0, NULL, HFILL }},
 279
 280         { &hf_x224_code, {
 281         "Code", "x224.code", FT_UINT8, BASE_HEX,
 282         VALS(code_vals), 0xf0, NULL, HFILL }},
 283
 284         { &hf_x224_src_ref, {
 285         "SRC-REF", "x224.src_ref", FT_UINT16, BASE_HEX,
 286         NULL, 0, NULL, HFILL }},
 287
 288         { &hf_x224_dst_ref, {
 289         "DST-REF", "x224.dst_ref", FT_UINT16, BASE_HEX,
 290         NULL, 0, NULL, HFILL }},
 291
 292         { &hf_x224_class, {
 293         "Class", "x224.class", FT_UINT8, BASE_HEX,
 294         VALS(class_option_vals), 0xf0, NULL, HFILL }},
 295
 296         { &hf_x224_rdp_rt, {
 297         "RDP Routing Token", "x224.rdp_rt", FT_STRING, BASE_NONE, NULL, 0,
 298         "Used for Remote Desktop Protocol (RDP) load balancing", HFILL }},
 299
 300         { &hf_x224_nr, {
 301         "NR", "x224.nr", FT_UINT8, BASE_HEX,
 302         NULL, 0x7f, NULL, HFILL }},
 303
 304         { &hf_x224_eot, {
 305         "EOT", "x224.eot", FT_BOOLEAN, 8,
 306         NULL, 0x80, NULL, HFILL }},
 307
 308         };
 309
 310         static gint *ett[] =
 311         {
 312                 &ett_x224,
 313         };
 314
 315         proto_x224 = proto_register_protocol("ITU-T Rec X.224", "X.224", "x224");
 316         proto_register_field_array(proto_x224, hf, array_length(hf));
 317         proto_register_subtree_array(ett, array_length(ett));
 318         new_register_dissector("x224", dissect_x224, proto_x224);
 319
 320 }
 321
 322 void
 323 proto_reg_handoff_x224(void)
 324 {
 325         t125_handle = find_dissector("t125");
 326 }