epan/dissectors/packet-sndcp-xid.c

   1 /* packet-sndcp-xid.c
   2  * Routines for Subnetwork Dependent Convergence Protocol (SNDCP) XID dissection
   3  * Used to dissect XID compression parameters negotiated in GSM (TS44.065)
   4  * Copyright 2008, Vincent Helfre <vincent.helfre [AT] ericsson.com>
   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 <stdlib.h>
  32
  33 #include <glib.h>
  34
  35 #include <epan/packet.h>
  36
  37
  38 /* Parameter types: TS 44.065 8
  39 */
  40 #define SNDCP_VERSION_PAR_TYPE 0
  41 #define DATA_COMPRESSION_PAR_TYPE 1
  42 #define PROTOCOL_COMPRESSION_PAR_TYPE 2
  43
  44 /* Algorithm identifiers: TS 44.065 6.6.1.1.4 and 6.5.1.1.4
  45 */
  46 #define ALGO_V42BIS 0
  47 #define ALGO_V44 1
  48 #define ALGO_RFC1144 0
  49 #define ALGO_RFC2507 1
  50 #define ALGO_ROHC 2
  51
  52 static const value_string sndcp_xid_dcomp_algo_str[] = {
  53         {0x0, "V.42 bis"},
  54         {0x1, "V.44"},
  55         {0, NULL}
  56 };
  57
  58 static const value_string sndcp_xid_pcomp_algo_str[] = {
  59         {0x0, "RFC 1144"},
  60         {0x1, "RFC 2507"},
  61         {0x2, "ROHC (RFC 3095)"},
  62         {0, NULL}
  63 };
  64
  65 typedef struct
  66 {
  67         guint8 nb_of_dcomp_pcomp; /* note that a DCOMP or a PCOMP is 4 bit wide */
  68         guint16 (**func_array_ptr) (tvbuff_t *, proto_tree *, guint16);
  69 } algo_parameters_t;
  70
  71 /* Initialize the protocol and registered fields
  72 */
  73 static int proto_sndcp_xid   = -1;
  74
  75 /* These fields are used to store store the algorithm ID
  76 * When the P bit is not set, try to decode the algo based on what whas stored.
  77 * Entity ranges from 0 to 31 (6.5.1.1.3)
  78 */
  79 static guint8 dcomp_entity_algo_id[32]={-1, -1, -1, -1, -1, -1, -1, -1,
  80                                                                                 -1, -1, -1, -1, -1, -1, -1, -1,
  81                                                                                 -1, -1, -1, -1, -1, -1, -1, -1,
  82                                                                                 -1, -1, -1, -1, -1, -1, -1, -1};
  83 static guint8 pcomp_entity_algo_id[32]={-1, -1, -1, -1, -1, -1, -1, -1,
  84                                                                                 -1, -1, -1, -1, -1, -1, -1, -1,
  85                                                                                 -1, -1, -1, -1, -1, -1, -1, -1,
  86                                                                                 -1, -1, -1, -1, -1, -1, -1, -1};
  87
  88
  89
  90 /* L3 XID parsing */
  91 static int hf_sndcp_xid_type = -1;
  92 static int hf_sndcp_xid_len = -1;
  93 static int hf_sndcp_xid_value = -1;
  94 static int hf_sndcp_xid_comp_pbit = -1;
  95 static int hf_sndcp_xid_comp_spare_byte1 = -1;
  96 static int hf_sndcp_xid_comp_entity = -1;
  97 static int hf_sndcp_xid_comp_spare_byte2 = -1;
  98 static int hf_sndcp_xid_comp_algo_id = -1;
  99 static int hf_sndcp_xid_comp_len = -1;
 100 /* There is currently a maximum of 15 DCOMP/PCOMP: 6.5.1.1.5 */
 101 static int hf_sndcp_xid_comp[15] = {-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1};
 102 static int hf_sndcp_xid_comp_spare = -1;
 103
 104 static int hf_element_applicable_nsapi_15 = -1;
 105 static int hf_element_applicable_nsapi_14 = -1;
 106 static int hf_element_applicable_nsapi_13 = -1;
 107 static int hf_element_applicable_nsapi_12 = -1;
 108 static int hf_element_applicable_nsapi_11 = -1;
 109 static int hf_element_applicable_nsapi_10 = -1;
 110 static int hf_element_applicable_nsapi_9 = -1;
 111 static int hf_element_applicable_nsapi_8 = -1;
 112 static int hf_element_applicable_nsapi_7 = -1;
 113 static int hf_element_applicable_nsapi_6 = -1;
 114 static int hf_element_applicable_nsapi_5 = -1;
 115 static int hf_element_applicable_nsapi_spare = -1;
 116
 117 static int hf_sndcp_xid_rfc1144_s0 = -1;
 118 static int hf_sndcp_xid_rfc2507_f_max_period_msb = -1;
 119 static int hf_sndcp_xid_rfc2507_f_max_period_lsb = -1;
 120 static int hf_sndcp_xid_rfc2507_f_max_time = -1;
 121 static int hf_sndcp_xid_rfc2507_max_header = -1;
 122 static int hf_sndcp_xid_rfc2507_tcp_space = -1;
 123 static int hf_sndcp_xid_rfc2507_non_tcp_space_msb = -1;
 124 static int hf_sndcp_xid_rfc2507_non_tcp_space_lsb = -1;
 125 static int hf_sndcp_xid_rohc_max_cid_spare = -1;
 126 static int hf_sndcp_xid_rohc_max_cid_msb = -1;
 127 static int hf_sndcp_xid_rohc_max_cid_lsb = -1;
 128 static int hf_sndcp_xid_rohc_max_header = -1;
 129 static int hf_sndcp_xid_rohc_profile_msb = -1;
 130 static int hf_sndcp_xid_rohc_profile_lsb = -1;
 131
 132 static int hf_sndcp_xid_V42bis_p0_spare = -1;
 133 static int hf_sndcp_xid_V42bis_p0 = -1;
 134 static int hf_sndcp_xid_V42bis_p1_msb = -1;
 135 static int hf_sndcp_xid_V42bis_p1_lsb = -1;
 136 static int hf_sndcp_xid_V42bis_p2 = -1;
 137 static int hf_sndcp_xid_V44_c0 = -1;
 138 static int hf_sndcp_xid_V44_c0_spare = -1;
 139 static int hf_sndcp_xid_V44_p0_spare = -1;
 140 static int hf_sndcp_xid_V44_p0 = -1;
 141 static int hf_sndcp_xid_V44_p1t_msb = -1;
 142 static int hf_sndcp_xid_V44_p1t_lsb = -1;
 143 static int hf_sndcp_xid_V44_p1r_msb = -1;
 144 static int hf_sndcp_xid_V44_p1r_lsb = -1;
 145 static int hf_sndcp_xid_V44_p3t_msb = -1;
 146 static int hf_sndcp_xid_V44_p3t_lsb = -1;
 147 static int hf_sndcp_xid_V44_p3r_msb = -1;
 148 static int hf_sndcp_xid_V44_p3r_lsb = -1;
 149
 150
 151 /* Initialize the subtree pointers
 152 */
 153 static gint ett_sndcp_xid                = -1;
 154 static gint ett_sndcp_xid_version_field  = -1;
 155 static gint ett_sndcp_comp_field        = -1;
 156
 157 static void parse_compression_parameters(tvbuff_t *tvb, proto_tree *tree, gboolean dcomp);
 158 /******************************************************/
 159 /* Compression algorithms element dissector functions */
 160 /******************************************************/
 161 static guint16 parse_applicable_nsapi(tvbuff_t *tvb, proto_tree *tree, guint16 offset)
 162 {
 163         guint8 nsapi_byte1, nsapi_byte2;
 164         nsapi_byte1 = tvb_get_guint8(tvb, offset);
 165         nsapi_byte2 = tvb_get_guint8(tvb, offset+1);
 166
 167         proto_tree_add_uint(tree, hf_element_applicable_nsapi_15, tvb, offset, 1, nsapi_byte1);
 168         proto_tree_add_uint(tree, hf_element_applicable_nsapi_14, tvb, offset, 1, nsapi_byte1);
 169         proto_tree_add_uint(tree, hf_element_applicable_nsapi_13, tvb, offset, 1, nsapi_byte1);
 170         proto_tree_add_uint(tree, hf_element_applicable_nsapi_12, tvb, offset, 1, nsapi_byte1);
 171         proto_tree_add_uint(tree, hf_element_applicable_nsapi_11, tvb, offset, 1, nsapi_byte1);
 172         proto_tree_add_uint(tree, hf_element_applicable_nsapi_10, tvb, offset, 1, nsapi_byte1);
 173         proto_tree_add_uint(tree, hf_element_applicable_nsapi_9, tvb, offset, 1, nsapi_byte1);
 174         proto_tree_add_uint(tree, hf_element_applicable_nsapi_8, tvb, offset, 1, nsapi_byte1);
 175
 176         proto_tree_add_uint(tree, hf_element_applicable_nsapi_7, tvb, offset+1, 1, nsapi_byte2);
 177         proto_tree_add_uint(tree, hf_element_applicable_nsapi_6, tvb, offset+1, 1, nsapi_byte2);
 178         proto_tree_add_uint(tree, hf_element_applicable_nsapi_5, tvb, offset+1, 1, nsapi_byte2);
 179         proto_tree_add_uint(tree, hf_element_applicable_nsapi_spare, tvb, offset+1, 1, nsapi_byte2);
 180
 181         return 2U;
 182 }
 183
 184 static guint16 parse_rfc1144_s0(tvbuff_t *tvb, proto_tree *tree, guint16 offset)
 185 {
 186         guint8 s0;
 187         s0 = tvb_get_guint8(tvb, offset);
 188
 189         proto_tree_add_uint(tree, hf_sndcp_xid_rfc1144_s0, tvb, offset, 1, s0);
 190
 191         return 1U;
 192 }
 193
 194 static guint16 parse_rfc2507_f_max_period(tvbuff_t *tvb, proto_tree *tree, guint16 offset)
 195 {
 196         guint8 f_max_period_byte1, f_max_period_byte2;
 197         f_max_period_byte1 = tvb_get_guint8(tvb, offset);
 198         f_max_period_byte2 = tvb_get_guint8(tvb, offset+1);
 199
 200         proto_tree_add_uint(tree, hf_sndcp_xid_rfc2507_f_max_period_msb, tvb, offset, 1, f_max_period_byte1);
 201         proto_tree_add_uint(tree, hf_sndcp_xid_rfc2507_f_max_period_lsb, tvb, offset, 1, f_max_period_byte2);
 202
 203         return 2U;
 204 }
 205
 206 static guint16 parse_rfc2507_f_max_time(tvbuff_t *tvb, proto_tree *tree, guint16 offset)
 207 {
 208         guint8 f_max_time;
 209         f_max_time = tvb_get_guint8(tvb, offset);
 210
 211         proto_tree_add_uint(tree, hf_sndcp_xid_rfc2507_f_max_time, tvb, offset, 1, f_max_time);
 212
 213         return 1U;
 214 }
 215
 216 static guint16 parse_rfc2507_max_header(tvbuff_t *tvb, proto_tree *tree, guint16 offset)
 217 {
 218         guint8 max_header;
 219         max_header = tvb_get_guint8(tvb, offset);
 220
 221         proto_tree_add_uint(tree, hf_sndcp_xid_rfc2507_max_header, tvb, offset, 1, max_header);
 222
 223         return 1U;
 224 }
 225
 226 static guint16 parse_rfc2507_tcp_space(tvbuff_t *tvb, proto_tree *tree, guint16 offset)
 227 {
 228         guint8 tcp_space;
 229         tcp_space = tvb_get_guint8(tvb, offset);
 230
 231         proto_tree_add_uint(tree, hf_sndcp_xid_rfc2507_tcp_space, tvb, offset, 1, tcp_space);
 232
 233         return 1U;
 234 }
 235
 236 static guint16 parse_rfc2507_non_tcp_space(tvbuff_t *tvb, proto_tree *tree, guint16 offset)
 237 {
 238         guint8 tcp_space_msb, tcp_space_lsb;
 239         tcp_space_msb = tvb_get_guint8(tvb, offset);
 240         tcp_space_lsb = tvb_get_guint8(tvb, offset+1);
 241
 242         proto_tree_add_uint(tree, hf_sndcp_xid_rfc2507_non_tcp_space_msb, tvb, offset, 1, tcp_space_msb);
 243         proto_tree_add_uint(tree, hf_sndcp_xid_rfc2507_non_tcp_space_lsb, tvb, offset, 1, tcp_space_lsb);
 244
 245         return 2U;
 246 }
 247
 248 static guint16 parse_rohc_max_cid(tvbuff_t *tvb, proto_tree *tree, guint16 offset)
 249 {
 250         guint8 max_cid_msb, max_cid_lsb;
 251         max_cid_msb = tvb_get_guint8(tvb, offset);
 252         max_cid_lsb = tvb_get_guint8(tvb, offset+1);
 253
 254         proto_tree_add_uint(tree, hf_sndcp_xid_rohc_max_cid_spare, tvb, offset, 1, max_cid_msb);
 255         proto_tree_add_uint(tree, hf_sndcp_xid_rohc_max_cid_msb, tvb, offset, 1, max_cid_msb);
 256         proto_tree_add_uint(tree, hf_sndcp_xid_rohc_max_cid_lsb, tvb, offset+1, 1, max_cid_lsb);
 257
 258         return 2U;
 259 }
 260 static guint16 parse_rohc_max_header(tvbuff_t *tvb, proto_tree *tree, guint16 offset)
 261 {
 262         guint8 max_header;
 263
 264         max_header = tvb_get_guint8(tvb, offset+1);
 265
 266         proto_tree_add_uint(tree, hf_sndcp_xid_rohc_max_header, tvb, offset+1, 1, max_header);
 267
 268         return 2U;
 269 }
 270
 271 static guint16 parse_rohc_profile(tvbuff_t *tvb, proto_tree *tree, guint16 offset)
 272 {
 273         guint8 profile_msb, profile_lsb;
 274         profile_msb = tvb_get_guint8(tvb, offset);
 275         profile_lsb = tvb_get_guint8(tvb, offset+1);
 276
 277         proto_tree_add_uint(tree, hf_sndcp_xid_rohc_profile_msb, tvb, offset, 1, profile_msb);
 278         proto_tree_add_uint(tree, hf_sndcp_xid_rohc_profile_lsb, tvb, offset+1, 1, profile_lsb);
 279
 280         return 2U;
 281 }
 282
 283 static guint16 parse_V42bis_p0(tvbuff_t *tvb, proto_tree *tree, guint16 offset)
 284 {
 285         guint8 p0;
 286
 287         p0 = tvb_get_guint8(tvb, offset);
 288
 289         proto_tree_add_uint(tree, hf_sndcp_xid_V42bis_p0_spare, tvb, offset, 1, p0);
 290         proto_tree_add_uint(tree, hf_sndcp_xid_V42bis_p0, tvb, offset, 1, p0);
 291
 292         return 1U;
 293 }
 294
 295 static guint16 parse_V42bis_p1(tvbuff_t *tvb, proto_tree *tree, guint16 offset)
 296 {
 297         guint8 p1_msb, p1_lsb;
 298
 299         p1_msb = tvb_get_guint8(tvb, offset);
 300         p1_lsb = tvb_get_guint8(tvb, offset+1);
 301
 302         proto_tree_add_uint(tree, hf_sndcp_xid_V42bis_p1_msb, tvb, offset, 1, p1_msb);
 303         proto_tree_add_uint(tree, hf_sndcp_xid_V42bis_p1_lsb, tvb, offset+1, 1, p1_lsb);
 304
 305         return 2U;
 306 }
 307
 308 static guint16 parse_V42bis_p2(tvbuff_t *tvb, proto_tree *tree, guint16 offset)
 309 {
 310         guint8 p2;
 311
 312         p2 = tvb_get_guint8(tvb, offset);
 313
 314         proto_tree_add_uint(tree, hf_sndcp_xid_V42bis_p2, tvb, offset, 1, p2);
 315
 316         return 1U;
 317 }
 318
 319 static guint16 parse_V44_c0(tvbuff_t *tvb, proto_tree *tree, guint16 offset)
 320 {
 321         guint8 c0;
 322
 323         c0 = tvb_get_guint8(tvb, offset);
 324         proto_tree_add_uint(tree, hf_sndcp_xid_V44_c0_spare, tvb, offset, 1, c0);
 325         proto_tree_add_uint(tree, hf_sndcp_xid_V44_c0, tvb, offset, 1, c0);
 326
 327         return 1U;
 328 }
 329
 330 static guint16 parse_V44_p0(tvbuff_t *tvb, proto_tree *tree, guint16 offset)
 331 {
 332         guint8 p0;
 333
 334         p0 = tvb_get_guint8(tvb, offset);
 335
 336         proto_tree_add_uint(tree, hf_sndcp_xid_V44_p0_spare, tvb, offset, 1, p0);
 337         proto_tree_add_uint(tree, hf_sndcp_xid_V44_p0, tvb, offset, 1, p0);
 338
 339         return 1U;
 340 }
 341
 342
 343 static guint16 parse_V44_p1t(tvbuff_t *tvb, proto_tree *tree, guint16 offset)
 344 {
 345         guint8 p1t_msb, p1t_lsb;
 346
 347         p1t_msb = tvb_get_guint8(tvb, offset);
 348         p1t_lsb = tvb_get_guint8(tvb, offset+1);
 349
 350         proto_tree_add_uint(tree, hf_sndcp_xid_V44_p1t_msb, tvb, offset, 1, p1t_msb);
 351         proto_tree_add_uint(tree, hf_sndcp_xid_V44_p1t_lsb, tvb, offset+1, 1, p1t_lsb);
 352
 353         return 2U;
 354 }
 355
 356 static guint16 parse_V44_p1r(tvbuff_t *tvb, proto_tree *tree, guint16 offset)
 357 {
 358         guint8 p1r_msb, p1r_lsb;
 359
 360         p1r_msb = tvb_get_guint8(tvb, offset);
 361         p1r_lsb = tvb_get_guint8(tvb, offset+1);
 362
 363         proto_tree_add_uint(tree, hf_sndcp_xid_V44_p1r_msb, tvb, offset, 1, p1r_msb);
 364         proto_tree_add_uint(tree, hf_sndcp_xid_V44_p1r_lsb, tvb, offset+1, 1, p1r_lsb);
 365
 366         return 2U;
 367 }
 368
 369 static guint16 parse_V44_p3t(tvbuff_t *tvb, proto_tree *tree, guint16 offset)
 370 {
 371         guint8 p3t_msb, p3t_lsb;
 372
 373         p3t_msb = tvb_get_guint8(tvb, offset);
 374         p3t_lsb = tvb_get_guint8(tvb, offset+1);
 375
 376         proto_tree_add_uint(tree, hf_sndcp_xid_V44_p3t_msb, tvb, offset, 1, p3t_msb);
 377         proto_tree_add_uint(tree, hf_sndcp_xid_V44_p3t_lsb, tvb, offset+1, 1, p3t_lsb);
 378
 379         return 2U;
 380 }
 381
 382 static guint16 parse_V44_p3r(tvbuff_t *tvb, proto_tree *tree, guint16 offset)
 383 {
 384         guint8 p3r_msb, p3r_lsb;
 385
 386         p3r_msb = tvb_get_guint8(tvb, offset);
 387         p3r_lsb = tvb_get_guint8(tvb, offset+1);
 388
 389         proto_tree_add_uint(tree, hf_sndcp_xid_V44_p3r_msb, tvb, offset, 1, p3r_msb);
 390         proto_tree_add_uint(tree, hf_sndcp_xid_V44_p3r_lsb, tvb, offset+1, 1, p3r_lsb);
 391
 392         return 2U;
 393 }
 394
 395
 396 /***************************************************/
 397 /* Compression algorithms element dissector arrays */
 398 /***************************************************/
 399 static guint16 (*rfc1144_elem_fcn[])(tvbuff_t *, proto_tree *, guint16) = {
 400     parse_applicable_nsapi,
 401         parse_rfc1144_s0,
 402         NULL
 403 };
 404
 405
 406 static guint16 (*rfc2507_elem_fcn[])(tvbuff_t *, proto_tree *, guint16) = {
 407         parse_applicable_nsapi,
 408         parse_rfc2507_f_max_period,
 409         parse_rfc2507_f_max_time,
 410         parse_rfc2507_max_header,
 411         parse_rfc2507_tcp_space,
 412         parse_rfc2507_non_tcp_space,
 413         NULL
 414 };
 415
 416 static guint16 (*rohc_elem_fcn[])(tvbuff_t *, proto_tree *, guint16) = {
 417         parse_applicable_nsapi,
 418         parse_rohc_max_cid,
 419         parse_rohc_max_header,
 420         parse_rohc_profile, /* Profile 1 */
 421         parse_rohc_profile, /* Profile 2 */
 422         parse_rohc_profile, /* Profile 3 */
 423         parse_rohc_profile, /* Profile 4 */
 424         parse_rohc_profile, /* Profile 5 */
 425         parse_rohc_profile, /* Profile 6 */
 426         parse_rohc_profile, /* Profile 7 */
 427         parse_rohc_profile, /* Profile 8 */
 428         parse_rohc_profile, /* Profile 9 */
 429         parse_rohc_profile, /* Profile 10 */
 430         parse_rohc_profile, /* Profile 11 */
 431         parse_rohc_profile, /* Profile 12 */
 432         parse_rohc_profile, /* Profile 13 */
 433         parse_rohc_profile, /* Profile 14 */
 434         parse_rohc_profile, /* Profile 15 */
 435         parse_rohc_profile, /* Profile 16 */
 436         NULL
 437 };
 438
 439 /* Array containing the number of pcomp and the function array pointer */
 440 static algo_parameters_t pcomp_algo_pars[] = {
 441         {2, rfc1144_elem_fcn},
 442         {5, rfc2507_elem_fcn},
 443         {2, rohc_elem_fcn}
 444 };
 445
 446 /* Data compression algorithms */
 447
 448 static guint16 (*v42bis_elem_fcn[])(tvbuff_t *, proto_tree *, guint16) = {
 449         parse_applicable_nsapi,
 450         parse_V42bis_p0,
 451         parse_V42bis_p1,
 452         parse_V42bis_p2,
 453         NULL
 454 };
 455
 456 static guint16 (*v44_elem_fcn[])(tvbuff_t *, proto_tree *, guint16) = {
 457         parse_applicable_nsapi,
 458         parse_V44_c0,
 459         parse_V44_p0,
 460         parse_V44_p1t,
 461         parse_V44_p1r,
 462         parse_V44_p3t,
 463         parse_V44_p3r,
 464         NULL
 465 };
 466
 467 /* Array containing the number of dcomp and the function array pointer */
 468 static algo_parameters_t dcomp_algo_pars[] = {
 469         {1, v42bis_elem_fcn},
 470         {2, v44_elem_fcn},
 471
 472 };
 473
 474 /* Code to actually dissect the packets
 475 */
 476 static void
 477 dissect_sndcp_xid(tvbuff_t *tvb, packet_info *pinfo _U_, proto_tree *tree)
 478 {
 479         /* Set up structures needed to add the protocol subtree and manage it
 480         */
 481         proto_item *ti, *version_item, *dcomp_item, *pcomp_item;
 482         proto_tree *sndcp_tree, *version_tree, *dcomp_tree, *pcomp_tree;
 483         guint16 offset = 0, l3_param_len;
 484         guint8 parameter_type, parameter_len;
 485
 486         /* create display subtree for the protocol
 487         */
 488         ti = proto_tree_add_item(tree, proto_sndcp_xid, tvb, 0, -1, ENC_NA);
 489         sndcp_tree = proto_item_add_subtree(ti, ett_sndcp_xid);
 490         l3_param_len = tvb_reported_length(tvb);
 491
 492         while (offset < l3_param_len-1)
 493         {
 494                 parameter_type = tvb_get_guint8(tvb, offset);
 495                 parameter_len = tvb_get_guint8(tvb, offset+1);
 496
 497                 if (parameter_type == SNDCP_VERSION_PAR_TYPE)
 498                 {
 499                         guint8 value = tvb_get_guint8(tvb, offset+2);
 500                         version_item = proto_tree_add_text(sndcp_tree, tvb, offset, parameter_len+2,
 501                                         "Version (SNDCP version number) - Value %d", value);
 502
 503                         version_tree = proto_item_add_subtree(version_item, ett_sndcp_xid_version_field);
 504                         proto_tree_add_uint(version_tree, hf_sndcp_xid_type, tvb, offset,
 505                         1, parameter_type);
 506                         proto_tree_add_uint(version_tree, hf_sndcp_xid_len, tvb, offset+1,
 507                         1, parameter_len);
 508                         proto_tree_add_uint(version_tree, hf_sndcp_xid_value, tvb, offset+2,
 509                         1, value);
 510                         offset += 3;
 511                 }
 512
 513                 else if (parameter_type == DATA_COMPRESSION_PAR_TYPE)
 514                 {
 515                         tvbuff_t * dcomp_tvb;
 516
 517                         dcomp_item = proto_tree_add_text(sndcp_tree, tvb, offset, parameter_len+2,
 518                                 "Data Compression");
 519                         dcomp_tree = proto_item_add_subtree(dcomp_item, ett_sndcp_comp_field);
 520                         proto_tree_add_uint(dcomp_tree, hf_sndcp_xid_type, tvb, offset,
 521                         1, parameter_type);
 522                         proto_tree_add_uint(dcomp_tree, hf_sndcp_xid_len, tvb, offset+1,
 523                         1, parameter_len);
 524                         offset += 2;
 525
 526                         dcomp_tvb = tvb_new_subset(tvb, offset, parameter_len, parameter_len);
 527                         parse_compression_parameters(dcomp_tvb, dcomp_tree, TRUE);
 528                         offset += parameter_len;
 529
 530
 531                 }
 532                 else if (parameter_type == PROTOCOL_COMPRESSION_PAR_TYPE)
 533                 {
 534                         tvbuff_t * pcomp_tvb;
 535
 536                         pcomp_item = proto_tree_add_text(sndcp_tree, tvb, offset, parameter_len+2,
 537                                 "Protocol Control Information Compression");
 538                         pcomp_tree = proto_item_add_subtree(pcomp_item, ett_sndcp_comp_field);
 539                         proto_tree_add_uint(pcomp_tree, hf_sndcp_xid_type, tvb, offset,
 540                         1, parameter_type);
 541                         proto_tree_add_uint(pcomp_tree, hf_sndcp_xid_len, tvb, offset+1,
 542                         1, parameter_len);
 543                         offset += 2;
 544
 545                         pcomp_tvb = tvb_new_subset(tvb, offset, parameter_len, parameter_len);
 546                         parse_compression_parameters(pcomp_tvb, pcomp_tree, FALSE);
 547                         offset += parameter_len;
 548
 549                 }
 550                 else
 551                 {
 552                         break; /* error: exit */
 553                 }
 554         }
 555 }
 556
 557
 558 static void parse_compression_parameters(tvbuff_t *tvb, proto_tree *tree, gboolean dcomp)
 559 {
 560         guint8 entity, len, algo_id;
 561         guint8 number_of_comp, i;
 562         gboolean p_bit_set;
 563         algo_parameters_t * algo_pars;
 564         guint8 function_index;
 565         proto_item *comp_entity_field = NULL;
 566         proto_tree *comp_entity_tree = NULL;
 567         guint16 tvb_len, offset=0 , new_offset, entity_offset;
 568         value_string const * comp_algo_str;
 569
 570         tvb_len = tvb_reported_length(tvb);
 571         if (tvb_len < 3) return; /* entity, algo and length bytes should always be present 6.5.1.1 and 6.6.1.1 */
 572
 573         /* Loop to decode each entity (cf Figure 10) */
 574         while (offset < tvb_len)
 575         {
 576                 /* Read the entity byte */
 577                 entity = tvb_get_guint8(tvb, offset);
 578                 p_bit_set = ((entity & 0x80) == 0x80) ? 1 : 0;
 579                 entity = entity & 0x1F;
 580
 581                 /* P bit is set: means that algo identifier and dcomp are present */
 582                 if (p_bit_set)
 583                 {
 584                         /* Read the algorithm id. TODO: store the algo in a different variable for each different entity */
 585                         algo_id = tvb_get_guint8(tvb, offset+1) & 0x1F;
 586
 587                         /* sanity check: check that the algo id that will be used inside the array has a valid range */
 588                         if (dcomp)
 589                         {
 590                                 if(algo_id <= ALGO_V44)
 591                                 {
 592                                         algo_pars = dcomp_algo_pars;
 593                                         dcomp_entity_algo_id[entity] = algo_id;
 594                                         comp_algo_str = sndcp_xid_dcomp_algo_str;
 595                                 }
 596                                 else return;
 597                         }
 598                         else
 599                         {
 600                                 if (algo_id <= ALGO_ROHC)
 601                                 {
 602                                         algo_pars = pcomp_algo_pars;
 603                                         pcomp_entity_algo_id[entity] = algo_id;
 604                                         comp_algo_str = sndcp_xid_pcomp_algo_str;
 605                                 }
 606                                 else return;
 607                         }
 608
 609                         /* Read the length */
 610                         len = tvb_get_guint8(tvb, offset+2);
 611
 612                         comp_entity_field = proto_tree_add_text(tree, tvb, offset, len + 3,
 613                                 "Entity %d, Algorithm %s",
 614                                 entity & 0x1F, val_to_str(algo_id & 0x1F, comp_algo_str,"Undefined Algorithm Identifier:%X"));
 615                         comp_entity_tree = proto_item_add_subtree(comp_entity_field, ett_sndcp_comp_field);
 616
 617                         proto_tree_add_uint(comp_entity_tree, hf_sndcp_xid_comp_pbit, tvb, offset, 1, p_bit_set << 7);
 618                         proto_tree_add_uint(comp_entity_tree, hf_sndcp_xid_comp_spare_byte1, tvb, offset, 1, entity);
 619                         proto_tree_add_uint(comp_entity_tree, hf_sndcp_xid_comp_entity, tvb, offset, 1, entity);
 620
 621                         proto_tree_add_uint(comp_entity_tree, hf_sndcp_xid_comp_spare_byte2, tvb, offset+1, 1, algo_id);
 622                         proto_tree_add_uint(comp_entity_tree, hf_sndcp_xid_comp_algo_id, tvb, offset+1, 1, algo_id);
 623                         proto_tree_add_uint(comp_entity_tree, hf_sndcp_xid_comp_len, tvb, offset+2, 1, len);
 624
 625                         /* Read the dcomp/pcomp field */
 626                         offset += 3; /* entity_offset will be used as the offset from length byte */
 627                         number_of_comp = algo_pars[algo_id].nb_of_dcomp_pcomp;
 628
 629                         for (i=0; i < (number_of_comp+1) / 2; i++)
 630                         {
 631                                 guint8 byte;
 632
 633                                 byte = tvb_get_guint8(tvb, offset+i);
 634                                 proto_tree_add_uint(comp_entity_tree, hf_sndcp_xid_comp[2*i], tvb, offset+i, 1, byte);
 635
 636                                 /* if there is an even number of dcomp/pcomp */
 637                                 if (2*i+1 < number_of_comp)
 638                                 {
 639                                         proto_tree_add_uint(comp_entity_tree, hf_sndcp_xid_comp[2*i+1], tvb, offset+i, 1, byte);
 640                                 }
 641                                 /* else there is padding in the end */
 642                                 else
 643                                 {
 644                                         proto_tree_add_uint(comp_entity_tree, hf_sndcp_xid_comp_spare, tvb, offset+i, 1, byte);
 645                                 }
 646
 647                         }
 648                         entity_offset = i;
 649                         function_index = 0;
 650
 651                         /* Process the elements byte per byte */
 652                         while ((entity_offset < len) && (algo_pars[algo_id].func_array_ptr[function_index] != NULL))
 653                         {
 654                                 new_offset = offset+entity_offset;
 655                                 entity_offset += algo_pars[algo_id].func_array_ptr[function_index](tvb, comp_entity_tree, new_offset);
 656                                 function_index++;
 657                         }
 658                         offset += entity_offset;
 659
 660                 }
 661                 else /* P bit not set */
 662                 {
 663                         len = tvb_get_guint8(tvb, offset+1);
 664
 665                         if (dcomp)
 666                         {
 667                                 algo_pars = dcomp_algo_pars;
 668                                 algo_id = dcomp_entity_algo_id[entity];
 669                                 comp_algo_str = sndcp_xid_dcomp_algo_str;
 670                         }
 671                         else
 672                         {
 673                                 algo_pars = pcomp_algo_pars;
 674                                 algo_id = pcomp_entity_algo_id[entity];
 675                                 comp_algo_str = sndcp_xid_pcomp_algo_str;
 676                         }
 677                         comp_entity_field = proto_tree_add_text(tree, tvb, offset, len + 2,
 678                                 "Entity %d decoded as Algorithm %s",
 679                                 entity & 0x1F, val_to_str(algo_id & 0x1F, comp_algo_str,"Undefined Algorithm Identifier:%X"));
 680
 681                         comp_entity_tree = proto_item_add_subtree(comp_entity_field, ett_sndcp_comp_field);
 682
 683                         proto_tree_add_uint(comp_entity_tree, hf_sndcp_xid_comp_pbit, tvb, offset, 1, p_bit_set << 7);
 684                         proto_tree_add_uint(comp_entity_tree, hf_sndcp_xid_comp_spare_byte1, tvb, offset, 1, entity);
 685                         proto_tree_add_uint(comp_entity_tree, hf_sndcp_xid_comp_entity, tvb, offset, 1, entity);
 686                         proto_tree_add_uint(comp_entity_tree, hf_sndcp_xid_comp_len, tvb, offset+2, 1, len);
 687
 688                         offset += 2;
 689                         entity_offset = 0;
 690                         function_index = 0;
 691
 692                         if (dcomp)
 693                         {
 694                                 if (algo_id > ALGO_V44) return;
 695                         }
 696                         else
 697                         {
 698                                 if (algo_id > ALGO_ROHC) return;
 699                         }
 700
 701                         /* Process the elements byte per byte */
 702                         while ((entity_offset < len) && (algo_pars[algo_id].func_array_ptr[function_index] != NULL))
 703                         {
 704                                 new_offset = offset+entity_offset;
 705                                 entity_offset += algo_pars[algo_id].func_array_ptr[function_index](tvb, comp_entity_tree, new_offset);
 706                                 function_index++;
 707                         }
 708                         offset += entity_offset;
 709                 }
 710         }
 711
 712         /* Else if length is lower than 3, the packet is not correctly formatted */
 713 }
 714
 715 /* Register the protocol with Wireshark
 716    this format is required because a script is used to build the C function
 717    that calls all the protocol registration.
 718 */
 719
 720 void
 721 proto_register_sndcp_xid(void)
 722 {
 723   /* Setup list of header fields
 724    */
 725         static hf_register_info hf[] = {
 726                 /* L3 XID Parameter Parsing Info */
 727                 {&hf_sndcp_xid_type,
 728                                 { "Parameter type","llcgprs.l3xidpartype", FT_UINT8, BASE_DEC, NULL, 0xFF, "Data", HFILL}},
 729                 {&hf_sndcp_xid_len,
 730                                 { "Length","llcgprs.l3xidparlen", FT_UINT8, BASE_DEC, NULL, 0xFF, "Data", HFILL}},
 731                 {&hf_sndcp_xid_value,
 732                                 { "Value","llcgprs.l3xidparvalue", FT_UINT8, BASE_DEC, NULL, 0xFF, "Data", HFILL}},
 733                 {&hf_sndcp_xid_comp_pbit,
 734                                 { "P bit","llcgprs.l3xiddcomppbit", FT_UINT8, BASE_DEC, NULL, 0x80, "Data", HFILL}},
 735                 {&hf_sndcp_xid_comp_spare_byte1,
 736                                 { "Spare","llcgprs.l3xidspare", FT_UINT8, BASE_HEX, NULL, 0x60, "Ignore", HFILL}},
 737                 {&hf_sndcp_xid_comp_entity,
 738                                 { "Entity","llcgprs.l3xidentity", FT_UINT8, BASE_DEC, NULL, 0x1F, "Data", HFILL}},
 739                 {&hf_sndcp_xid_comp_spare_byte2,
 740                                 { "Spare","llcgprs.l3xidspare", FT_UINT8, BASE_HEX, NULL, 0xE0, "Ignore", HFILL}},
 741                 {&hf_sndcp_xid_comp_algo_id,
 742                                 { "Algorithm identifier","llcgprs.l3xidalgoid", FT_UINT8, BASE_DEC, NULL, 0x1F, "Data", HFILL}},
 743                 {&hf_sndcp_xid_comp_len,
 744                                 { "Length","llcgprs.l3xidcomplen", FT_UINT8, BASE_DEC, NULL, 0xFF, "Data", HFILL}},
 745                 {&hf_sndcp_xid_comp[0],
 746                                 { "DCOMP1","llcgprs.l3xiddcomp", FT_UINT8, BASE_DEC, NULL, 0xF0, "Data", HFILL}},
 747                 {&hf_sndcp_xid_comp[1],
 748                                 { "DCOMP2","llcgprs.l3xiddcomp", FT_UINT8, BASE_DEC, NULL, 0x0F, "Data", HFILL}},
 749                 {&hf_sndcp_xid_comp[2],
 750                                 { "DCOMP3","llcgprs.l3xiddcomp", FT_UINT8, BASE_DEC, NULL, 0xF0, "Data", HFILL}},
 751                 {&hf_sndcp_xid_comp[3],
 752                                 { "DCOMP4","llcgprs.l3xiddcomp", FT_UINT8, BASE_DEC, NULL, 0x0F, "Data", HFILL}},
 753                 {&hf_sndcp_xid_comp[4],
 754                                 { "DCOMP5","llcgprs.l3xiddcomp", FT_UINT8, BASE_DEC, NULL, 0xF0, "Data", HFILL}},
 755                 {&hf_sndcp_xid_comp[5],
 756                                 { "DCOMP6","llcgprs.l3xiddcomp", FT_UINT8, BASE_DEC, NULL, 0x0F, "Data", HFILL}},
 757                 {&hf_sndcp_xid_comp[6],
 758                                 { "DCOMP7","llcgprs.l3xiddcomp", FT_UINT8, BASE_DEC, NULL, 0xF0, "Data", HFILL}},
 759                 {&hf_sndcp_xid_comp[7],
 760                                 { "DCOMP8","llcgprs.l3xiddcomp", FT_UINT8, BASE_DEC, NULL, 0x0F, "Data", HFILL}},
 761                 {&hf_sndcp_xid_comp[8],
 762                                 { "DCOMP9","llcgprs.l3xiddcomp", FT_UINT8, BASE_DEC, NULL, 0xF0, "Data", HFILL}},
 763                 {&hf_sndcp_xid_comp[9],
 764                                 { "DCOMP10","llcgprs.l3xiddcomp", FT_UINT8, BASE_DEC, NULL, 0x0F, "Data", HFILL}},
 765                 {&hf_sndcp_xid_comp[10],
 766                                 { "DCOMP11","llcgprs.l3xiddcomp", FT_UINT8, BASE_DEC, NULL, 0xF0, "Data", HFILL}},
 767                 {&hf_sndcp_xid_comp[11],
 768                                 { "DCOMP12","llcgprs.l3xiddcomp", FT_UINT8, BASE_DEC, NULL, 0x0F, "Data", HFILL}},
 769                 {&hf_sndcp_xid_comp[12],
 770                                 { "DCOMP13","llcgprs.l3xiddcomp", FT_UINT8, BASE_DEC, NULL, 0xF0, "Data", HFILL}},
 771                 {&hf_sndcp_xid_comp[13],
 772                                 { "DCOMP14","llcgprs.l3xiddcomp", FT_UINT8, BASE_DEC, NULL, 0x0F, "Data", HFILL}},
 773                 {&hf_sndcp_xid_comp[14],
 774                                 { "DCOMP15","llcgprs.l3xiddcomp", FT_UINT8, BASE_DEC, NULL, 0xF0, "Data", HFILL}},
 775                 {&hf_sndcp_xid_comp_spare,
 776                                 { "Spare","llcgprs.l3xidspare", FT_UINT8, BASE_HEX, NULL, 0x0F, "Ignore", HFILL}},
 777                 {&hf_element_applicable_nsapi_15,
 778                                 { "NSAPI 15","sndcpxid.nsapi15", FT_UINT8, BASE_DEC, NULL, 0x80, "Data", HFILL}},
 779                 {&hf_element_applicable_nsapi_14,
 780                                 { "NSAPI 14","sndcpxid.nsapi14", FT_UINT8, BASE_DEC, NULL, 0x40, "Data", HFILL}},
 781                 {&hf_element_applicable_nsapi_13,
 782                                 { "NSAPI 13","sndcpxid.nsapi13", FT_UINT8, BASE_DEC, NULL, 0x20, "Data", HFILL}},
 783                 {&hf_element_applicable_nsapi_12,
 784                                 { "NSAPI 12","sndcpxid.nsapi12", FT_UINT8, BASE_DEC, NULL, 0x10, "Data", HFILL}},
 785                 {&hf_element_applicable_nsapi_11,
 786                                 { "NSAPI 11","sndcpxid.nsapi11", FT_UINT8, BASE_DEC, NULL, 0x08, "Data", HFILL}},
 787                 {&hf_element_applicable_nsapi_10,
 788                                 { "NSAPI 10","sndcpxid.nsapi10", FT_UINT8, BASE_DEC, NULL, 0x04, "Data", HFILL}},
 789                 {&hf_element_applicable_nsapi_9,
 790                                 { "NSAPI 9","sndcpxid.nsapi9", FT_UINT8, BASE_DEC, NULL, 0x02, "Data", HFILL}},
 791                 {&hf_element_applicable_nsapi_8,
 792                                 { "NSAPI 8","sndcpxid.nsapi8", FT_UINT8, BASE_DEC, NULL, 0x01, "Data", HFILL}},
 793                 {&hf_element_applicable_nsapi_7,
 794                                 { "NSAPI 7","sndcpxid.nsapi7", FT_UINT8, BASE_DEC, NULL, 0x80, "Data", HFILL}},
 795                 {&hf_element_applicable_nsapi_6,
 796                                 { "NSAPI 6","sndcpxid.nsapi6", FT_UINT8, BASE_DEC, NULL, 0x40, "Data", HFILL}},
 797                 {&hf_element_applicable_nsapi_5,
 798                                 { "NSAPI 5","sndcpxid.nsapi5", FT_UINT8, BASE_DEC, NULL, 0x20, "Data", HFILL}},
 799                 {&hf_element_applicable_nsapi_spare,
 800                                 { "Spare","sndcpxid.spare", FT_UINT8, BASE_DEC, NULL, 0x1F, "Ignore", HFILL}},
 801                 {&hf_sndcp_xid_rfc1144_s0,
 802                                 { "S0 - 1","sndcpxid.rfc1144_s0", FT_UINT8, BASE_DEC, NULL, 0xFF, "Data", HFILL}},
 803                 {&hf_sndcp_xid_rfc2507_f_max_period_msb,
 804                                 { "F Max Period MSB","sndcpxid.rfc2507_f_max_period_msb", FT_UINT8, BASE_HEX, NULL, 0xFF, "Data", HFILL}},
 805                 {&hf_sndcp_xid_rfc2507_f_max_period_lsb,
 806                                 { "F Max Period LSB","sndcpxid.rfc2507_f_max_period_lsb", FT_UINT8, BASE_HEX, NULL, 0xFF, "Data", HFILL}},
 807                 {&hf_sndcp_xid_rfc2507_f_max_time,
 808                                 { "F Max Time","sndcpxid.rfc2507_f_max_time", FT_UINT8, BASE_DEC, NULL, 0xFF, "Data", HFILL}},
 809                 {&hf_sndcp_xid_rfc2507_max_header,
 810                                 { "Max Header","sndcpxid.rfc2507_max_header", FT_UINT8, BASE_DEC, NULL, 0xFF, "Data", HFILL}},
 811                 {&hf_sndcp_xid_rfc2507_tcp_space,
 812                                 { "TCP Space","sndcpxid.rfc2507_max_tcp_space", FT_UINT8, BASE_DEC, NULL, 0xFF, "Data", HFILL}},
 813                 {&hf_sndcp_xid_rfc2507_non_tcp_space_msb,
 814                                 { "TCP non space MSB","sndcpxid.rfc2507_max_non_tcp_space_msb", FT_UINT8, BASE_HEX, NULL, 0xFF, "Data", HFILL}},
 815                 {&hf_sndcp_xid_rfc2507_non_tcp_space_lsb,
 816                                 { "TCP non space LSB","sndcpxid.rfc2507_max_non_tcp_space_lsb", FT_UINT8, BASE_HEX, NULL, 0xFF, "Data", HFILL}},
 817                 {&hf_sndcp_xid_rohc_max_cid_spare,
 818                                 { "Spare","sndcpxid.rohc_max_cid_spare", FT_UINT8, BASE_DEC, NULL, 0xC0, "Ignore", HFILL}},
 819                 {&hf_sndcp_xid_rohc_max_cid_msb,
 820                                 { "Max CID MSB","sndcpxid.rohc_max_cid_msb", FT_UINT8, BASE_HEX, NULL, 0x3F, "Data", HFILL}},
 821                 {&hf_sndcp_xid_rohc_max_cid_lsb,
 822                                 { "Max CID LSB","sndcpxid.rohc_max_cid_lsb", FT_UINT8, BASE_HEX, NULL, 0xFF, "Data", HFILL}},
 823                 {&hf_sndcp_xid_rohc_max_header,
 824                                 { "Max header","sndcpxid.rohc_max_header", FT_UINT8, BASE_DEC, NULL, 0xFF, "Data", HFILL}},
 825                 {&hf_sndcp_xid_rohc_profile_msb,
 826                                 { "Profile MSB","sndcpxid.rohc_profile_msb", FT_UINT8, BASE_HEX, NULL, 0xFF, "Data", HFILL}},
 827                 {&hf_sndcp_xid_rohc_profile_lsb,
 828                                 { "Profile LSB","sndcpxid.rohc_profile_lsb", FT_UINT8, BASE_HEX, NULL, 0xFF, "Data", HFILL}},
 829                 {&hf_sndcp_xid_V42bis_p0_spare,
 830                                 { "Spare","sndcpxid.V42bis_p0spare", FT_UINT8, BASE_DEC, NULL, 0xFC, "Ignore", HFILL}},
 831                 {&hf_sndcp_xid_V42bis_p0,
 832                                 { "P0","sndcpxid.V42bis_p0", FT_UINT8, BASE_HEX, NULL, 0x03, "Data", HFILL}},
 833                 {&hf_sndcp_xid_V42bis_p1_msb,
 834                                 { "P1 MSB","sndcpxid.V42bis_p1_msb", FT_UINT8, BASE_HEX, NULL, 0xFF, "Data", HFILL}},
 835                 {&hf_sndcp_xid_V42bis_p1_lsb,
 836                                 { "P1 LSB","sndcpxid.V42bis_p1_lsb", FT_UINT8, BASE_HEX, NULL, 0xFF, "Data", HFILL}},
 837                 {&hf_sndcp_xid_V42bis_p2,
 838                                 { "P2","sndcpxid.V42bis_p2", FT_UINT8, BASE_HEX, NULL, 0xFF, "Data", HFILL}},
 839                 {&hf_sndcp_xid_V44_c0_spare,
 840                                 { "P2","sndcpxid.V44_c0_spare", FT_UINT8, BASE_HEX, NULL, 0x3F, "Ignore", HFILL}},
 841                 {&hf_sndcp_xid_V44_c0,
 842                                 { "P2","sndcpxid.V44_c0", FT_UINT8, BASE_HEX, NULL, 0xC0, "Data", HFILL}},
 843                 {&hf_sndcp_xid_V44_p0_spare,
 844                                 { "Spare","sndcpxid.V44_p0spare", FT_UINT8, BASE_DEC, NULL, 0xFC, "Ignore", HFILL}},
 845                 {&hf_sndcp_xid_V44_p0,
 846                                 { "P0","sndcpxid.V44_p0", FT_UINT8, BASE_HEX, NULL, 0x03, "Data", HFILL}},
 847                 {&hf_sndcp_xid_V44_p1t_msb,
 848                                 { "P1t MSB","sndcpxid.V44_p1t_msb", FT_UINT8, BASE_HEX, NULL, 0xFF, "Data", HFILL}},
 849                 {&hf_sndcp_xid_V44_p1t_lsb,
 850                                 { "P1t LSB","sndcpxid.V44_p1t_lsb", FT_UINT8, BASE_HEX, NULL, 0xFF, "Data", HFILL}},
 851                 {&hf_sndcp_xid_V44_p1r_msb,
 852                                 { "P1r MSB","sndcpxid.V44_p1r_msb", FT_UINT8, BASE_HEX, NULL, 0xFF, "Data", HFILL}},
 853                 {&hf_sndcp_xid_V44_p1r_lsb,
 854                                 { "P1r LSB","sndcpxid.V44_p1r_lsb", FT_UINT8, BASE_HEX, NULL, 0xFF, "Data", HFILL}},
 855                 {&hf_sndcp_xid_V44_p3t_msb,
 856                                 { "P3t MSB","sndcpxid.V44_p3t_msb", FT_UINT8, BASE_HEX, NULL, 0xFF, "Data", HFILL}},
 857                 {&hf_sndcp_xid_V44_p3t_lsb,
 858                                 { "P3t LSB","sndcpxid.V44_p3t_lsb", FT_UINT8, BASE_HEX, NULL, 0xFF, "Data", HFILL}},
 859                 {&hf_sndcp_xid_V44_p3r_msb,
 860                                 { "P3r MSB","sndcpxid.V44_p3r_msb", FT_UINT8, BASE_HEX, NULL, 0xFF, "Data", HFILL}},
 861                 {&hf_sndcp_xid_V44_p3r_lsb,
 862                                 { "P3r LSB","sndcpxid.V44_p3r_lsb", FT_UINT8, BASE_HEX, NULL, 0xFF, "Data", HFILL}},
 863         };
 864
 865    /* Setup protocol subtree array */
 866   static gint *ett[] = {
 867     &ett_sndcp_xid,
 868     &ett_sndcp_xid_version_field,
 869     &ett_sndcp_comp_field
 870   };
 871
 872   /* Register the protocol name and description */
 873   proto_sndcp_xid = proto_register_protocol("Subnetwork Dependent Convergence Protocol XID",
 874                                         "SNDCP XID", "sndcpxid");
 875
 876   /* Required function calls to register the header fields and subtrees used */
 877   proto_register_field_array(proto_sndcp_xid, hf, array_length(hf));
 878   proto_register_subtree_array(ett, array_length(ett));
 879   register_dissector("sndcpxid", dissect_sndcp_xid, proto_sndcp_xid);
 880 }
 881
 882 /* If this dissector uses sub-dissector registration add a registration routine.
 883    This format is required because a script is used to find these routines and
 884    create the code that calls these routines.
 885 */
 886 void
 887 proto_reg_handoff_sndcp_xid(void)
 888 {
 889 }