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 <epan/conversation.h>
  34 #include <epan/wmem/wmem.h>
  35
  36 void proto_register_x224(void);
  37 void proto_reg_handoff_x224(void);
  38
  39 /* X.224 header fields             */
  40 static int proto_x224                   = -1;
  41 static int hf_x224_length               = -1;
  42 static int hf_x224_code                 = -1;
  43 static int hf_x224_src_ref              = -1;
  44 static int hf_x224_dst_ref              = -1;
  45 static int hf_x224_class                = -1;
  46 static int hf_x224_rdp_rt               = -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  klass;
  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         gint len, next_offset;
 104
 105         /*DST-REF is always 0 */
 106         offset+=2;
 107
 108         /*SRC-REF*/
 109         proto_tree_add_item(tree, hf_x224_src_ref, tvb, offset, 2, ENC_BIG_ENDIAN);
 110         offset+=2;
 111
 112         /* class options */
 113         /*class = tvb_get_guint8(tvb, offset);*/
 114         proto_tree_add_item(tree, hf_x224_class, tvb, offset, 1, ENC_BIG_ENDIAN);
 115         offset+=1;
 116
 117         if(tvb_length_remaining(tvb, offset) > 0) {
 118                 len = tvb_find_line_end(tvb, offset, -1, &next_offset, TRUE);
 119                 proto_tree_add_item(tree, hf_x224_rdp_rt, tvb, offset, len,
 120                                     ENC_ASCII|ENC_NA);
 121                 offset = next_offset;
 122         }
 123
 124         return offset;
 125 }
 126
 127 static int
 128 dissect_x224_cc(packet_info *pinfo _U_, proto_tree *tree, tvbuff_t *tvb, int offset, x224_conv_info_t *x224_info)
 129 {
 130         guint8 klass;
 131
 132         /*DST-REF */
 133         proto_tree_add_item(tree, hf_x224_dst_ref, tvb, offset, 2, ENC_BIG_ENDIAN);
 134         offset+=2;
 135
 136         /*SRC-REF*/
 137         proto_tree_add_item(tree, hf_x224_src_ref, tvb, offset, 2, ENC_BIG_ENDIAN);
 138         offset+=2;
 139
 140         /* class options */
 141         klass = tvb_get_guint8(tvb, offset);
 142         proto_tree_add_item(tree, hf_x224_class, tvb, offset, 1, ENC_BIG_ENDIAN);
 143         x224_info->klass = klass;
 144         offset+=1;
 145
 146         return offset;
 147 }
 148
 149 static int
 150 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)
 151 {
 152         proto_item *item = NULL;
 153         tvbuff_t *next_tvb;
 154
 155         switch (x224_info->klass >>4) {
 156         case 2:
 157         case 3:
 158         case 4:
 159                 /*DST-REF */
 160                 proto_tree_add_item(tree, hf_x224_dst_ref, tvb, offset, 2, ENC_BIG_ENDIAN);
 161                 offset+=2;
 162                 break;
 163         }
 164
 165         item = proto_tree_add_uint(tree, hf_x224_class, tvb, 0, 0, x224_info->klass);
 166         PROTO_ITEM_SET_GENERATED(item);
 167
 168
 169         /* EOT / NR */
 170         proto_tree_add_item(tree, hf_x224_eot, tvb, offset, 1, ENC_BIG_ENDIAN);
 171         proto_tree_add_item(tree, hf_x224_nr, tvb, offset, 1, ENC_BIG_ENDIAN);
 172         offset+=1;
 173
 174
 175         next_tvb = tvb_new_subset_remaining(tvb, offset);
 176         call_dissector(t125_handle, next_tvb, pinfo, parent_tree);
 177
 178         return offset;
 179 }
 180
 181 static int
 182 dissect_x224(tvbuff_t *tvb, packet_info *pinfo, proto_tree *parent_tree, void *data _U_)
 183 {
 184         proto_tree *tree = NULL;
 185         proto_item *item = NULL;
 186         int offset = 0 ;
 187         guint8 code, length;
 188         conversation_t *conversation;
 189         x224_conv_info_t *x224_info;
 190
 191         col_set_str(pinfo->cinfo, COL_PROTOCOL, "X.224");
 192         col_clear(pinfo->cinfo, COL_INFO);
 193
 194         length = tvb_get_guint8(tvb, offset);
 195         if (parent_tree) {
 196                 item = proto_tree_add_item(parent_tree, proto_x224, tvb, offset, length+1, ENC_NA);
 197                 tree = proto_item_add_subtree(item, ett_x224);
 198         }
 199
 200
 201         /* length indicator */
 202         proto_tree_add_item(tree, hf_x224_length, tvb, offset, 1, ENC_BIG_ENDIAN);
 203         offset+=1;
 204
 205         /* code */
 206         code = tvb_get_guint8(tvb, offset);
 207         proto_tree_add_item(tree, hf_x224_code, tvb, offset, 1, ENC_BIG_ENDIAN);
 208         offset+=1;
 209
 210         col_add_fstr(pinfo->cinfo, COL_INFO, "%s (0x%02x)",
 211                         val_to_str(code>>4, code_vals, "Unknown code :%x"),
 212                         code);
 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 = (x224_conv_info_t *)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 = wmem_new(wmem_file_scope(), x224_conv_info_t);
 231                 x224_info->klass=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 }