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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  25  */
  26
  27 #include "config.h"
  28
  29 #include <glib.h>
  30
  31 #include <epan/packet.h>
  32
  33
  34 /* Parameter types: TS 44.065 8
  35 */
  36 #define SNDCP_VERSION_PAR_TYPE 0
  37 #define DATA_COMPRESSION_PAR_TYPE 1
  38 #define PROTOCOL_COMPRESSION_PAR_TYPE 2
  39
  40 /* Algorithm identifiers: TS 44.065 6.6.1.1.4 and 6.5.1.1.4
  41 */
  42 #define ALGO_V42BIS 0
  43 #define ALGO_V44 1
  44 #define ALGO_RFC1144 0
  45 #define ALGO_RFC2507 1
  46 #define ALGO_ROHC 2
  47
  48 static const value_string sndcp_xid_dcomp_algo_str[] = {
  49         {0x0, "V.42 bis"},
  50         {0x1, "V.44"},
  51         {0, NULL}
  52 };
  53
  54 static const value_string sndcp_xid_pcomp_algo_str[] = {
  55         {0x0, "RFC 1144"},
  56         {0x1, "RFC 2507"},
  57         {0x2, "ROHC (RFC 3095)"},
  58         {0, NULL}
  59 };
  60
  61 typedef struct
  62 {
  63         guint8 nb_of_dcomp_pcomp; /* note that a DCOMP or a PCOMP is 4 bit wide */
  64         guint16 (**func_array_ptr) (tvbuff_t *, proto_tree *, guint16);
  65 } algo_parameters_t;
  66
  67 /* Initialize the protocol and registered fields
  68 */
  69 static int proto_sndcp_xid   = -1;
  70
  71 /* These fields are used to store store the algorithm ID
  72 * When the P bit is not set, try to decode the algo based on what whas stored.
  73 * Entity ranges from 0 to 31 (6.5.1.1.3)
  74 */
  75 static guint8 dcomp_entity_algo_id[32]={-1, -1, -1, -1, -1, -1, -1, -1,
  76                                                                                 -1, -1, -1, -1, -1, -1, -1, -1,
  77                                                                                 -1, -1, -1, -1, -1, -1, -1, -1,
  78                                                                                 -1, -1, -1, -1, -1, -1, -1, -1};
  79 static guint8 pcomp_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
  84
  85
  86 /* L3 XID parsing */
  87 static int hf_sndcp_xid_type = -1;
  88 static int hf_sndcp_xid_len = -1;
  89 static int hf_sndcp_xid_value = -1;
  90 static int hf_sndcp_xid_comp_pbit = -1;
  91 static int hf_sndcp_xid_comp_spare_byte1 = -1;
  92 static int hf_sndcp_xid_comp_entity = -1;
  93 static int hf_sndcp_xid_comp_spare_byte2 = -1;
  94 static int hf_sndcp_xid_comp_algo_id = -1;
  95 static int hf_sndcp_xid_comp_len = -1;
  96 /* There is currently a maximum of 15 DCOMP/PCOMP: 6.5.1.1.5 */
  97 static int hf_sndcp_xid_comp[15] = {-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1};
  98 static int hf_sndcp_xid_comp_spare = -1;
  99
 100 static int hf_element_applicable_nsapi_15 = -1;
 101 static int hf_element_applicable_nsapi_14 = -1;
 102 static int hf_element_applicable_nsapi_13 = -1;
 103 static int hf_element_applicable_nsapi_12 = -1;
 104 static int hf_element_applicable_nsapi_11 = -1;
 105 static int hf_element_applicable_nsapi_10 = -1;
 106 static int hf_element_applicable_nsapi_9 = -1;
 107 static int hf_element_applicable_nsapi_8 = -1;
 108 static int hf_element_applicable_nsapi_7 = -1;
 109 static int hf_element_applicable_nsapi_6 = -1;
 110 static int hf_element_applicable_nsapi_5 = -1;
 111 static int hf_element_applicable_nsapi_spare = -1;
 112
 113 static int hf_sndcp_xid_rfc1144_s0 = -1;
 114 static int hf_sndcp_xid_rfc2507_f_max_period_msb = -1;
 115 static int hf_sndcp_xid_rfc2507_f_max_period_lsb = -1;
 116 static int hf_sndcp_xid_rfc2507_f_max_time = -1;
 117 static int hf_sndcp_xid_rfc2507_max_header = -1;
 118 static int hf_sndcp_xid_rfc2507_tcp_space = -1;
 119 static int hf_sndcp_xid_rfc2507_non_tcp_space_msb = -1;
 120 static int hf_sndcp_xid_rfc2507_non_tcp_space_lsb = -1;
 121 static int hf_sndcp_xid_rohc_max_cid_spare = -1;
 122 static int hf_sndcp_xid_rohc_max_cid_msb = -1;
 123 static int hf_sndcp_xid_rohc_max_cid_lsb = -1;
 124 static int hf_sndcp_xid_rohc_max_header = -1;
 125 static int hf_sndcp_xid_rohc_profile_msb = -1;
 126 static int hf_sndcp_xid_rohc_profile_lsb = -1;
 127
 128 static int hf_sndcp_xid_V42bis_p0_spare = -1;
 129 static int hf_sndcp_xid_V42bis_p0 = -1;
 130 static int hf_sndcp_xid_V42bis_p1_msb = -1;
 131 static int hf_sndcp_xid_V42bis_p1_lsb = -1;
 132 static int hf_sndcp_xid_V42bis_p2 = -1;
 133 static int hf_sndcp_xid_V44_c0 = -1;
 134 static int hf_sndcp_xid_V44_c0_spare = -1;
 135 static int hf_sndcp_xid_V44_p0_spare = -1;
 136 static int hf_sndcp_xid_V44_p0 = -1;
 137 static int hf_sndcp_xid_V44_p1t_msb = -1;
 138 static int hf_sndcp_xid_V44_p1t_lsb = -1;
 139 static int hf_sndcp_xid_V44_p1r_msb = -1;
 140 static int hf_sndcp_xid_V44_p1r_lsb = -1;
 141 static int hf_sndcp_xid_V44_p3t_msb = -1;
 142 static int hf_sndcp_xid_V44_p3t_lsb = -1;
 143 static int hf_sndcp_xid_V44_p3r_msb = -1;
 144 static int hf_sndcp_xid_V44_p3r_lsb = -1;
 145
 146
 147 /* Initialize the subtree pointers
 148 */
 149 static gint ett_sndcp_xid                = -1;
 150 static gint ett_sndcp_xid_version_field  = -1;
 151 static gint ett_sndcp_comp_field        = -1;
 152
 153 static void parse_compression_parameters(tvbuff_t *tvb, proto_tree *tree, gboolean dcomp);
 154 /******************************************************/
 155 /* Compression algorithms element dissector functions */
 156 /******************************************************/
 157 static guint16 parse_applicable_nsapi(tvbuff_t *tvb, proto_tree *tree, guint16 offset)
 158 {
 159         guint8 nsapi_byte1, nsapi_byte2;
 160         nsapi_byte1 = tvb_get_guint8(tvb, offset);
 161         nsapi_byte2 = tvb_get_guint8(tvb, offset+1);
 162
 163         proto_tree_add_uint(tree, hf_element_applicable_nsapi_15, tvb, offset, 1, nsapi_byte1);
 164         proto_tree_add_uint(tree, hf_element_applicable_nsapi_14, tvb, offset, 1, nsapi_byte1);
 165         proto_tree_add_uint(tree, hf_element_applicable_nsapi_13, tvb, offset, 1, nsapi_byte1);
 166         proto_tree_add_uint(tree, hf_element_applicable_nsapi_12, tvb, offset, 1, nsapi_byte1);
 167         proto_tree_add_uint(tree, hf_element_applicable_nsapi_11, tvb, offset, 1, nsapi_byte1);
 168         proto_tree_add_uint(tree, hf_element_applicable_nsapi_10, tvb, offset, 1, nsapi_byte1);
 169         proto_tree_add_uint(tree, hf_element_applicable_nsapi_9, tvb, offset, 1, nsapi_byte1);
 170         proto_tree_add_uint(tree, hf_element_applicable_nsapi_8, tvb, offset, 1, nsapi_byte1);
 171
 172         proto_tree_add_uint(tree, hf_element_applicable_nsapi_7, tvb, offset+1, 1, nsapi_byte2);
 173         proto_tree_add_uint(tree, hf_element_applicable_nsapi_6, tvb, offset+1, 1, nsapi_byte2);
 174         proto_tree_add_uint(tree, hf_element_applicable_nsapi_5, tvb, offset+1, 1, nsapi_byte2);
 175         proto_tree_add_uint(tree, hf_element_applicable_nsapi_spare, tvb, offset+1, 1, nsapi_byte2);
 176
 177         return 2U;
 178 }
 179
 180 static guint16 parse_rfc1144_s0(tvbuff_t *tvb, proto_tree *tree, guint16 offset)
 181 {
 182         guint8 s0;
 183         s0 = tvb_get_guint8(tvb, offset);
 184
 185         proto_tree_add_uint(tree, hf_sndcp_xid_rfc1144_s0, tvb, offset, 1, s0);
 186
 187         return 1U;
 188 }
 189
 190 static guint16 parse_rfc2507_f_max_period(tvbuff_t *tvb, proto_tree *tree, guint16 offset)
 191 {
 192         guint8 f_max_period_byte1, f_max_period_byte2;
 193         f_max_period_byte1 = tvb_get_guint8(tvb, offset);
 194         f_max_period_byte2 = tvb_get_guint8(tvb, offset+1);
 195
 196         proto_tree_add_uint(tree, hf_sndcp_xid_rfc2507_f_max_period_msb, tvb, offset, 1, f_max_period_byte1);
 197         proto_tree_add_uint(tree, hf_sndcp_xid_rfc2507_f_max_period_lsb, tvb, offset, 1, f_max_period_byte2);
 198
 199         return 2U;
 200 }
 201
 202 static guint16 parse_rfc2507_f_max_time(tvbuff_t *tvb, proto_tree *tree, guint16 offset)
 203 {
 204         guint8 f_max_time;
 205         f_max_time = tvb_get_guint8(tvb, offset);
 206
 207         proto_tree_add_uint(tree, hf_sndcp_xid_rfc2507_f_max_time, tvb, offset, 1, f_max_time);
 208
 209         return 1U;
 210 }
 211
 212 static guint16 parse_rfc2507_max_header(tvbuff_t *tvb, proto_tree *tree, guint16 offset)
 213 {
 214         guint8 max_header;
 215         max_header = tvb_get_guint8(tvb, offset);
 216
 217         proto_tree_add_uint(tree, hf_sndcp_xid_rfc2507_max_header, tvb, offset, 1, max_header);
 218
 219         return 1U;
 220 }
 221
 222 static guint16 parse_rfc2507_tcp_space(tvbuff_t *tvb, proto_tree *tree, guint16 offset)
 223 {
 224         guint8 tcp_space;
 225         tcp_space = tvb_get_guint8(tvb, offset);
 226
 227         proto_tree_add_uint(tree, hf_sndcp_xid_rfc2507_tcp_space, tvb, offset, 1, tcp_space);
 228
 229         return 1U;
 230 }
 231
 232 static guint16 parse_rfc2507_non_tcp_space(tvbuff_t *tvb, proto_tree *tree, guint16 offset)
 233 {
 234         guint8 tcp_space_msb, tcp_space_lsb;
 235         tcp_space_msb = tvb_get_guint8(tvb, offset);
 236         tcp_space_lsb = tvb_get_guint8(tvb, offset+1);
 237
 238         proto_tree_add_uint(tree, hf_sndcp_xid_rfc2507_non_tcp_space_msb, tvb, offset, 1, tcp_space_msb);
 239         proto_tree_add_uint(tree, hf_sndcp_xid_rfc2507_non_tcp_space_lsb, tvb, offset, 1, tcp_space_lsb);
 240
 241         return 2U;
 242 }
 243
 244 static guint16 parse_rohc_max_cid(tvbuff_t *tvb, proto_tree *tree, guint16 offset)
 245 {
 246         guint8 max_cid_msb, max_cid_lsb;
 247         max_cid_msb = tvb_get_guint8(tvb, offset);
 248         max_cid_lsb = tvb_get_guint8(tvb, offset+1);
 249
 250         proto_tree_add_uint(tree, hf_sndcp_xid_rohc_max_cid_spare, tvb, offset, 1, max_cid_msb);
 251         proto_tree_add_uint(tree, hf_sndcp_xid_rohc_max_cid_msb, tvb, offset, 1, max_cid_msb);
 252         proto_tree_add_uint(tree, hf_sndcp_xid_rohc_max_cid_lsb, tvb, offset+1, 1, max_cid_lsb);
 253
 254         return 2U;
 255 }
 256 static guint16 parse_rohc_max_header(tvbuff_t *tvb, proto_tree *tree, guint16 offset)
 257 {
 258         guint8 max_header;
 259
 260         max_header = tvb_get_guint8(tvb, offset+1);
 261
 262         proto_tree_add_uint(tree, hf_sndcp_xid_rohc_max_header, tvb, offset+1, 1, max_header);
 263
 264         return 2U;
 265 }
 266
 267 static guint16 parse_rohc_profile(tvbuff_t *tvb, proto_tree *tree, guint16 offset)
 268 {
 269         guint8 profile_msb, profile_lsb;
 270         profile_msb = tvb_get_guint8(tvb, offset);
 271         profile_lsb = tvb_get_guint8(tvb, offset+1);
 272
 273         proto_tree_add_uint(tree, hf_sndcp_xid_rohc_profile_msb, tvb, offset, 1, profile_msb);
 274         proto_tree_add_uint(tree, hf_sndcp_xid_rohc_profile_lsb, tvb, offset+1, 1, profile_lsb);
 275
 276         return 2U;
 277 }
 278
 279 static guint16 parse_V42bis_p0(tvbuff_t *tvb, proto_tree *tree, guint16 offset)
 280 {
 281         guint8 p0;
 282
 283         p0 = tvb_get_guint8(tvb, offset);
 284
 285         proto_tree_add_uint(tree, hf_sndcp_xid_V42bis_p0_spare, tvb, offset, 1, p0);
 286         proto_tree_add_uint(tree, hf_sndcp_xid_V42bis_p0, tvb, offset, 1, p0);
 287
 288         return 1U;
 289 }
 290
 291 static guint16 parse_V42bis_p1(tvbuff_t *tvb, proto_tree *tree, guint16 offset)
 292 {
 293         guint8 p1_msb, p1_lsb;
 294
 295         p1_msb = tvb_get_guint8(tvb, offset);
 296         p1_lsb = tvb_get_guint8(tvb, offset+1);
 297
 298         proto_tree_add_uint(tree, hf_sndcp_xid_V42bis_p1_msb, tvb, offset, 1, p1_msb);
 299         proto_tree_add_uint(tree, hf_sndcp_xid_V42bis_p1_lsb, tvb, offset+1, 1, p1_lsb);
 300
 301         return 2U;
 302 }
 303
 304 static guint16 parse_V42bis_p2(tvbuff_t *tvb, proto_tree *tree, guint16 offset)
 305 {
 306         guint8 p2;
 307
 308         p2 = tvb_get_guint8(tvb, offset);
 309
 310         proto_tree_add_uint(tree, hf_sndcp_xid_V42bis_p2, tvb, offset, 1, p2);
 311
 312         return 1U;
 313 }
 314
 315 static guint16 parse_V44_c0(tvbuff_t *tvb, proto_tree *tree, guint16 offset)
 316 {
 317         guint8 c0;
 318
 319         c0 = tvb_get_guint8(tvb, offset);
 320         proto_tree_add_uint(tree, hf_sndcp_xid_V44_c0_spare, tvb, offset, 1, c0);
 321         proto_tree_add_uint(tree, hf_sndcp_xid_V44_c0, tvb, offset, 1, c0);
 322
 323         return 1U;
 324 }
 325
 326 static guint16 parse_V44_p0(tvbuff_t *tvb, proto_tree *tree, guint16 offset)
 327 {
 328         guint8 p0;
 329
 330         p0 = tvb_get_guint8(tvb, offset);
 331
 332         proto_tree_add_uint(tree, hf_sndcp_xid_V44_p0_spare, tvb, offset, 1, p0);
 333         proto_tree_add_uint(tree, hf_sndcp_xid_V44_p0, tvb, offset, 1, p0);
 334
 335         return 1U;
 336 }
 337
 338
 339 static guint16 parse_V44_p1t(tvbuff_t *tvb, proto_tree *tree, guint16 offset)
 340 {
 341         guint8 p1t_msb, p1t_lsb;
 342
 343         p1t_msb = tvb_get_guint8(tvb, offset);
 344         p1t_lsb = tvb_get_guint8(tvb, offset+1);
 345
 346         proto_tree_add_uint(tree, hf_sndcp_xid_V44_p1t_msb, tvb, offset, 1, p1t_msb);
 347         proto_tree_add_uint(tree, hf_sndcp_xid_V44_p1t_lsb, tvb, offset+1, 1, p1t_lsb);
 348
 349         return 2U;
 350 }
 351
 352 static guint16 parse_V44_p1r(tvbuff_t *tvb, proto_tree *tree, guint16 offset)
 353 {
 354         guint8 p1r_msb, p1r_lsb;
 355
 356         p1r_msb = tvb_get_guint8(tvb, offset);
 357         p1r_lsb = tvb_get_guint8(tvb, offset+1);
 358
 359         proto_tree_add_uint(tree, hf_sndcp_xid_V44_p1r_msb, tvb, offset, 1, p1r_msb);
 360         proto_tree_add_uint(tree, hf_sndcp_xid_V44_p1r_lsb, tvb, offset+1, 1, p1r_lsb);
 361
 362         return 2U;
 363 }
 364
 365 static guint16 parse_V44_p3t(tvbuff_t *tvb, proto_tree *tree, guint16 offset)
 366 {
 367         guint8 p3t_msb, p3t_lsb;
 368
 369         p3t_msb = tvb_get_guint8(tvb, offset);
 370         p3t_lsb = tvb_get_guint8(tvb, offset+1);
 371
 372         proto_tree_add_uint(tree, hf_sndcp_xid_V44_p3t_msb, tvb, offset, 1, p3t_msb);
 373         proto_tree_add_uint(tree, hf_sndcp_xid_V44_p3t_lsb, tvb, offset+1, 1, p3t_lsb);
 374
 375         return 2U;
 376 }
 377
 378 static guint16 parse_V44_p3r(tvbuff_t *tvb, proto_tree *tree, guint16 offset)
 379 {
 380         guint8 p3r_msb, p3r_lsb;
 381
 382         p3r_msb = tvb_get_guint8(tvb, offset);
 383         p3r_lsb = tvb_get_guint8(tvb, offset+1);
 384
 385         proto_tree_add_uint(tree, hf_sndcp_xid_V44_p3r_msb, tvb, offset, 1, p3r_msb);
 386         proto_tree_add_uint(tree, hf_sndcp_xid_V44_p3r_lsb, tvb, offset+1, 1, p3r_lsb);
 387
 388         return 2U;
 389 }
 390
 391
 392 /***************************************************/
 393 /* Compression algorithms element dissector arrays */
 394 /***************************************************/
 395 static guint16 (*rfc1144_elem_fcn[])(tvbuff_t *, proto_tree *, guint16) = {
 396     parse_applicable_nsapi,
 397         parse_rfc1144_s0,
 398         NULL
 399 };
 400
 401
 402 static guint16 (*rfc2507_elem_fcn[])(tvbuff_t *, proto_tree *, guint16) = {
 403         parse_applicable_nsapi,
 404         parse_rfc2507_f_max_period,
 405         parse_rfc2507_f_max_time,
 406         parse_rfc2507_max_header,
 407         parse_rfc2507_tcp_space,
 408         parse_rfc2507_non_tcp_space,
 409         NULL
 410 };
 411
 412 static guint16 (*rohc_elem_fcn[])(tvbuff_t *, proto_tree *, guint16) = {
 413         parse_applicable_nsapi,
 414         parse_rohc_max_cid,
 415         parse_rohc_max_header,
 416         parse_rohc_profile, /* Profile 1 */
 417         parse_rohc_profile, /* Profile 2 */
 418         parse_rohc_profile, /* Profile 3 */
 419         parse_rohc_profile, /* Profile 4 */
 420         parse_rohc_profile, /* Profile 5 */
 421         parse_rohc_profile, /* Profile 6 */
 422         parse_rohc_profile, /* Profile 7 */
 423         parse_rohc_profile, /* Profile 8 */
 424         parse_rohc_profile, /* Profile 9 */
 425         parse_rohc_profile, /* Profile 10 */
 426         parse_rohc_profile, /* Profile 11 */
 427         parse_rohc_profile, /* Profile 12 */
 428         parse_rohc_profile, /* Profile 13 */
 429         parse_rohc_profile, /* Profile 14 */
 430         parse_rohc_profile, /* Profile 15 */
 431         parse_rohc_profile, /* Profile 16 */
 432         NULL
 433 };
 434
 435 /* Array containing the number of pcomp and the function array pointer */
 436 static algo_parameters_t pcomp_algo_pars[] = {
 437         {2, rfc1144_elem_fcn},
 438         {5, rfc2507_elem_fcn},
 439         {2, rohc_elem_fcn}
 440 };
 441
 442 /* Data compression algorithms */
 443
 444 static guint16 (*v42bis_elem_fcn[])(tvbuff_t *, proto_tree *, guint16) = {
 445         parse_applicable_nsapi,
 446         parse_V42bis_p0,
 447         parse_V42bis_p1,
 448         parse_V42bis_p2,
 449         NULL
 450 };
 451
 452 static guint16 (*v44_elem_fcn[])(tvbuff_t *, proto_tree *, guint16) = {
 453         parse_applicable_nsapi,
 454         parse_V44_c0,
 455         parse_V44_p0,
 456         parse_V44_p1t,
 457         parse_V44_p1r,
 458         parse_V44_p3t,
 459         parse_V44_p3r,
 460         NULL
 461 };
 462
 463 /* Array containing the number of dcomp and the function array pointer */
 464 static algo_parameters_t dcomp_algo_pars[] = {
 465         {1, v42bis_elem_fcn},
 466         {2, v44_elem_fcn},
 467
 468 };
 469
 470 /* Code to actually dissect the packets
 471 */
 472 static void
 473 dissect_sndcp_xid(tvbuff_t *tvb, packet_info *pinfo _U_, proto_tree *tree)
 474 {
 475         /* Set up structures needed to add the protocol subtree and manage it
 476         */
 477         proto_item *ti, *version_item, *dcomp_item, *pcomp_item;
 478         proto_tree *sndcp_tree, *version_tree, *dcomp_tree, *pcomp_tree;
 479         guint16 offset = 0, l3_param_len;
 480         guint8 parameter_type, parameter_len;
 481
 482         /* create display subtree for the protocol
 483         */
 484         ti = proto_tree_add_item(tree, proto_sndcp_xid, tvb, 0, -1, ENC_NA);
 485         sndcp_tree = proto_item_add_subtree(ti, ett_sndcp_xid);
 486         l3_param_len = tvb_reported_length(tvb);
 487
 488         while (offset < l3_param_len-1)
 489         {
 490                 parameter_type = tvb_get_guint8(tvb, offset);
 491                 parameter_len = tvb_get_guint8(tvb, offset+1);
 492
 493                 if (parameter_type == SNDCP_VERSION_PAR_TYPE)
 494                 {
 495                         guint8 value = tvb_get_guint8(tvb, offset+2);
 496                         version_item = proto_tree_add_text(sndcp_tree, tvb, offset, parameter_len+2,
 497                                         "Version (SNDCP version number) - Value %d", value);
 498
 499                         version_tree = proto_item_add_subtree(version_item, ett_sndcp_xid_version_field);
 500                         proto_tree_add_uint(version_tree, hf_sndcp_xid_type, tvb, offset,
 501                         1, parameter_type);
 502                         proto_tree_add_uint(version_tree, hf_sndcp_xid_len, tvb, offset+1,
 503                         1, parameter_len);
 504                         proto_tree_add_uint(version_tree, hf_sndcp_xid_value, tvb, offset+2,
 505                         1, value);
 506                         offset += 3;
 507                 }
 508
 509                 else if (parameter_type == DATA_COMPRESSION_PAR_TYPE)
 510                 {
 511                         tvbuff_t * dcomp_tvb;
 512
 513                         dcomp_item = proto_tree_add_text(sndcp_tree, tvb, offset, parameter_len+2,
 514                                 "Data Compression");
 515                         dcomp_tree = proto_item_add_subtree(dcomp_item, ett_sndcp_comp_field);
 516                         proto_tree_add_uint(dcomp_tree, hf_sndcp_xid_type, tvb, offset,
 517                         1, parameter_type);
 518                         proto_tree_add_uint(dcomp_tree, hf_sndcp_xid_len, tvb, offset+1,
 519                         1, parameter_len);
 520                         offset += 2;
 521
 522                         dcomp_tvb = tvb_new_subset(tvb, offset, parameter_len, parameter_len);
 523                         parse_compression_parameters(dcomp_tvb, dcomp_tree, TRUE);
 524                         offset += parameter_len;
 525
 526
 527                 }
 528                 else if (parameter_type == PROTOCOL_COMPRESSION_PAR_TYPE)
 529                 {
 530                         tvbuff_t * pcomp_tvb;
 531
 532                         pcomp_item = proto_tree_add_text(sndcp_tree, tvb, offset, parameter_len+2,
 533                                 "Protocol Control Information Compression");
 534                         pcomp_tree = proto_item_add_subtree(pcomp_item, ett_sndcp_comp_field);
 535                         proto_tree_add_uint(pcomp_tree, hf_sndcp_xid_type, tvb, offset,
 536                         1, parameter_type);
 537                         proto_tree_add_uint(pcomp_tree, hf_sndcp_xid_len, tvb, offset+1,
 538                         1, parameter_len);
 539                         offset += 2;
 540
 541                         pcomp_tvb = tvb_new_subset(tvb, offset, parameter_len, parameter_len);
 542                         parse_compression_parameters(pcomp_tvb, pcomp_tree, FALSE);
 543                         offset += parameter_len;
 544
 545                 }
 546                 else
 547                 {
 548                         break; /* error: exit */
 549                 }
 550         }
 551 }
 552
 553
 554 static void parse_compression_parameters(tvbuff_t *tvb, proto_tree *tree, gboolean dcomp)
 555 {
 556         guint8 entity, len, algo_id;
 557         guint8 number_of_comp, i;
 558         gboolean p_bit_set;
 559         algo_parameters_t * algo_pars;
 560         guint8 function_index;
 561         proto_item *comp_entity_field = NULL;
 562         proto_tree *comp_entity_tree = NULL;
 563         guint16 tvb_len, offset=0 , new_offset, entity_offset;
 564         value_string const * comp_algo_str;
 565
 566         tvb_len = tvb_reported_length(tvb);
 567         if (tvb_len < 3) return; /* entity, algo and length bytes should always be present 6.5.1.1 and 6.6.1.1 */
 568
 569         /* Loop to decode each entity (cf Figure 10) */
 570         while (offset < tvb_len)
 571         {
 572                 /* Read the entity byte */
 573                 entity = tvb_get_guint8(tvb, offset);
 574                 p_bit_set = ((entity & 0x80) == 0x80) ? 1 : 0;
 575                 entity = entity & 0x1F;
 576
 577                 /* P bit is set: means that algo identifier and dcomp are present */
 578                 if (p_bit_set)
 579                 {
 580                         /* Read the algorithm id. TODO: store the algo in a different variable for each different entity */
 581                         algo_id = tvb_get_guint8(tvb, offset+1) & 0x1F;
 582
 583                         /* sanity check: check that the algo id that will be used inside the array has a valid range */
 584                         if (dcomp)
 585                         {
 586                                 if(algo_id <= ALGO_V44)
 587                                 {
 588                                         algo_pars = dcomp_algo_pars;
 589                                         dcomp_entity_algo_id[entity] = algo_id;
 590                                         comp_algo_str = sndcp_xid_dcomp_algo_str;
 591                                 }
 592                                 else return;
 593                         }
 594                         else
 595                         {
 596                                 if (algo_id <= ALGO_ROHC)
 597                                 {
 598                                         algo_pars = pcomp_algo_pars;
 599                                         pcomp_entity_algo_id[entity] = algo_id;
 600                                         comp_algo_str = sndcp_xid_pcomp_algo_str;
 601                                 }
 602                                 else return;
 603                         }
 604
 605                         /* Read the length */
 606                         len = tvb_get_guint8(tvb, offset+2);
 607
 608                         comp_entity_field = proto_tree_add_text(tree, tvb, offset, len + 3,
 609                                 "Entity %d, Algorithm %s",
 610                                 entity & 0x1F, val_to_str(algo_id & 0x1F, comp_algo_str,"Undefined Algorithm Identifier:%X"));
 611                         comp_entity_tree = proto_item_add_subtree(comp_entity_field, ett_sndcp_comp_field);
 612
 613                         proto_tree_add_uint(comp_entity_tree, hf_sndcp_xid_comp_pbit, tvb, offset, 1, p_bit_set << 7);
 614                         proto_tree_add_uint(comp_entity_tree, hf_sndcp_xid_comp_spare_byte1, tvb, offset, 1, entity);
 615                         proto_tree_add_uint(comp_entity_tree, hf_sndcp_xid_comp_entity, tvb, offset, 1, entity);
 616
 617                         proto_tree_add_uint(comp_entity_tree, hf_sndcp_xid_comp_spare_byte2, tvb, offset+1, 1, algo_id);
 618                         proto_tree_add_uint(comp_entity_tree, hf_sndcp_xid_comp_algo_id, tvb, offset+1, 1, algo_id);
 619                         proto_tree_add_uint(comp_entity_tree, hf_sndcp_xid_comp_len, tvb, offset+2, 1, len);
 620
 621                         /* Read the dcomp/pcomp field */
 622                         offset += 3; /* entity_offset will be used as the offset from length byte */
 623                         number_of_comp = algo_pars[algo_id].nb_of_dcomp_pcomp;
 624
 625                         for (i=0; i < (number_of_comp+1) / 2; i++)
 626                         {
 627                                 guint8 byte;
 628
 629                                 byte = tvb_get_guint8(tvb, offset+i);
 630                                 proto_tree_add_uint(comp_entity_tree, hf_sndcp_xid_comp[2*i], tvb, offset+i, 1, byte);
 631
 632                                 /* if there is an even number of dcomp/pcomp */
 633                                 if (2*i+1 < number_of_comp)
 634                                 {
 635                                         proto_tree_add_uint(comp_entity_tree, hf_sndcp_xid_comp[2*i+1], tvb, offset+i, 1, byte);
 636                                 }
 637                                 /* else there is padding in the end */
 638                                 else
 639                                 {
 640                                         proto_tree_add_uint(comp_entity_tree, hf_sndcp_xid_comp_spare, tvb, offset+i, 1, byte);
 641                                 }
 642
 643                         }
 644                         entity_offset = i;
 645                         function_index = 0;
 646
 647                         /* Process the elements byte per byte */
 648                         while ((entity_offset < len) && (algo_pars[algo_id].func_array_ptr[function_index] != NULL))
 649                         {
 650                                 new_offset = offset+entity_offset;
 651                                 entity_offset += algo_pars[algo_id].func_array_ptr[function_index](tvb, comp_entity_tree, new_offset);
 652                                 function_index++;
 653                         }
 654                         offset += entity_offset;
 655
 656                 }
 657                 else /* P bit not set */
 658                 {
 659                         len = tvb_get_guint8(tvb, offset+1);
 660
 661                         if (dcomp)
 662                         {
 663                                 algo_pars = dcomp_algo_pars;
 664                                 algo_id = dcomp_entity_algo_id[entity];
 665                                 comp_algo_str = sndcp_xid_dcomp_algo_str;
 666                         }
 667                         else
 668                         {
 669                                 algo_pars = pcomp_algo_pars;
 670                                 algo_id = pcomp_entity_algo_id[entity];
 671                                 comp_algo_str = sndcp_xid_pcomp_algo_str;
 672                         }
 673                         comp_entity_field = proto_tree_add_text(tree, tvb, offset, len + 2,
 674                                 "Entity %d decoded as Algorithm %s",
 675                                 entity & 0x1F, val_to_str(algo_id & 0x1F, comp_algo_str,"Undefined Algorithm Identifier:%X"));
 676
 677                         comp_entity_tree = proto_item_add_subtree(comp_entity_field, ett_sndcp_comp_field);
 678
 679                         proto_tree_add_uint(comp_entity_tree, hf_sndcp_xid_comp_pbit, tvb, offset, 1, p_bit_set << 7);
 680                         proto_tree_add_uint(comp_entity_tree, hf_sndcp_xid_comp_spare_byte1, tvb, offset, 1, entity);
 681                         proto_tree_add_uint(comp_entity_tree, hf_sndcp_xid_comp_entity, tvb, offset, 1, entity);
 682                         proto_tree_add_uint(comp_entity_tree, hf_sndcp_xid_comp_len, tvb, offset+2, 1, len);
 683
 684                         offset += 2;
 685                         entity_offset = 0;
 686                         function_index = 0;
 687
 688                         if (dcomp)
 689                         {
 690                                 if (algo_id > ALGO_V44) return;
 691                         }
 692                         else
 693                         {
 694                                 if (algo_id > ALGO_ROHC) return;
 695                         }
 696
 697                         /* Process the elements byte per byte */
 698                         while ((entity_offset < len) && (algo_pars[algo_id].func_array_ptr[function_index] != NULL))
 699                         {
 700                                 new_offset = offset+entity_offset;
 701                                 entity_offset += algo_pars[algo_id].func_array_ptr[function_index](tvb, comp_entity_tree, new_offset);
 702                                 function_index++;
 703                         }
 704                         offset += entity_offset;
 705                 }
 706         }
 707
 708         /* Else if length is lower than 3, the packet is not correctly formatted */
 709 }
 710
 711 /* Register the protocol with Wireshark
 712    this format is required because a script is used to build the C function
 713    that calls all the protocol registration.
 714 */
 715
 716 void
 717 proto_register_sndcp_xid(void)
 718 {
 719   /* Setup list of header fields
 720    */
 721         static hf_register_info hf[] = {
 722                 /* L3 XID Parameter Parsing Info */
 723                 {&hf_sndcp_xid_type,
 724                                 { "Parameter type","llcgprs.l3xidpartype", FT_UINT8, BASE_DEC, NULL, 0xFF, "Data", HFILL}},
 725                 {&hf_sndcp_xid_len,
 726                                 { "Length","llcgprs.l3xidparlen", FT_UINT8, BASE_DEC, NULL, 0xFF, "Data", HFILL}},
 727                 {&hf_sndcp_xid_value,
 728                                 { "Value","llcgprs.l3xidparvalue", FT_UINT8, BASE_DEC, NULL, 0xFF, "Data", HFILL}},
 729                 {&hf_sndcp_xid_comp_pbit,
 730                                 { "P bit","llcgprs.l3xiddcomppbit", FT_UINT8, BASE_DEC, NULL, 0x80, "Data", HFILL}},
 731                 {&hf_sndcp_xid_comp_spare_byte1,
 732                                 { "Spare","llcgprs.l3xidspare", FT_UINT8, BASE_HEX, NULL, 0x60, "Ignore", HFILL}},
 733                 {&hf_sndcp_xid_comp_entity,
 734                                 { "Entity","llcgprs.l3xidentity", FT_UINT8, BASE_DEC, NULL, 0x1F, "Data", HFILL}},
 735                 {&hf_sndcp_xid_comp_spare_byte2,
 736                                 { "Spare","llcgprs.l3xidspare", FT_UINT8, BASE_HEX, NULL, 0xE0, "Ignore", HFILL}},
 737                 {&hf_sndcp_xid_comp_algo_id,
 738                                 { "Algorithm identifier","llcgprs.l3xidalgoid", FT_UINT8, BASE_DEC, NULL, 0x1F, "Data", HFILL}},
 739                 {&hf_sndcp_xid_comp_len,
 740                                 { "Length","llcgprs.l3xidcomplen", FT_UINT8, BASE_DEC, NULL, 0xFF, "Data", HFILL}},
 741                 {&hf_sndcp_xid_comp[0],
 742                                 { "DCOMP1","llcgprs.l3xiddcomp", FT_UINT8, BASE_DEC, NULL, 0xF0, "Data", HFILL}},
 743                 {&hf_sndcp_xid_comp[1],
 744                                 { "DCOMP2","llcgprs.l3xiddcomp", FT_UINT8, BASE_DEC, NULL, 0x0F, "Data", HFILL}},
 745                 {&hf_sndcp_xid_comp[2],
 746                                 { "DCOMP3","llcgprs.l3xiddcomp", FT_UINT8, BASE_DEC, NULL, 0xF0, "Data", HFILL}},
 747                 {&hf_sndcp_xid_comp[3],
 748                                 { "DCOMP4","llcgprs.l3xiddcomp", FT_UINT8, BASE_DEC, NULL, 0x0F, "Data", HFILL}},
 749                 {&hf_sndcp_xid_comp[4],
 750                                 { "DCOMP5","llcgprs.l3xiddcomp", FT_UINT8, BASE_DEC, NULL, 0xF0, "Data", HFILL}},
 751                 {&hf_sndcp_xid_comp[5],
 752                                 { "DCOMP6","llcgprs.l3xiddcomp", FT_UINT8, BASE_DEC, NULL, 0x0F, "Data", HFILL}},
 753                 {&hf_sndcp_xid_comp[6],
 754                                 { "DCOMP7","llcgprs.l3xiddcomp", FT_UINT8, BASE_DEC, NULL, 0xF0, "Data", HFILL}},
 755                 {&hf_sndcp_xid_comp[7],
 756                                 { "DCOMP8","llcgprs.l3xiddcomp", FT_UINT8, BASE_DEC, NULL, 0x0F, "Data", HFILL}},
 757                 {&hf_sndcp_xid_comp[8],
 758                                 { "DCOMP9","llcgprs.l3xiddcomp", FT_UINT8, BASE_DEC, NULL, 0xF0, "Data", HFILL}},
 759                 {&hf_sndcp_xid_comp[9],
 760                                 { "DCOMP10","llcgprs.l3xiddcomp", FT_UINT8, BASE_DEC, NULL, 0x0F, "Data", HFILL}},
 761                 {&hf_sndcp_xid_comp[10],
 762                                 { "DCOMP11","llcgprs.l3xiddcomp", FT_UINT8, BASE_DEC, NULL, 0xF0, "Data", HFILL}},
 763                 {&hf_sndcp_xid_comp[11],
 764                                 { "DCOMP12","llcgprs.l3xiddcomp", FT_UINT8, BASE_DEC, NULL, 0x0F, "Data", HFILL}},
 765                 {&hf_sndcp_xid_comp[12],
 766                                 { "DCOMP13","llcgprs.l3xiddcomp", FT_UINT8, BASE_DEC, NULL, 0xF0, "Data", HFILL}},
 767                 {&hf_sndcp_xid_comp[13],
 768                                 { "DCOMP14","llcgprs.l3xiddcomp", FT_UINT8, BASE_DEC, NULL, 0x0F, "Data", HFILL}},
 769                 {&hf_sndcp_xid_comp[14],
 770                                 { "DCOMP15","llcgprs.l3xiddcomp", FT_UINT8, BASE_DEC, NULL, 0xF0, "Data", HFILL}},
 771                 {&hf_sndcp_xid_comp_spare,
 772                                 { "Spare","llcgprs.l3xidspare", FT_UINT8, BASE_HEX, NULL, 0x0F, "Ignore", HFILL}},
 773                 {&hf_element_applicable_nsapi_15,
 774                                 { "NSAPI 15","sndcpxid.nsapi15", FT_UINT8, BASE_DEC, NULL, 0x80, "Data", HFILL}},
 775                 {&hf_element_applicable_nsapi_14,
 776                                 { "NSAPI 14","sndcpxid.nsapi14", FT_UINT8, BASE_DEC, NULL, 0x40, "Data", HFILL}},
 777                 {&hf_element_applicable_nsapi_13,
 778                                 { "NSAPI 13","sndcpxid.nsapi13", FT_UINT8, BASE_DEC, NULL, 0x20, "Data", HFILL}},
 779                 {&hf_element_applicable_nsapi_12,
 780                                 { "NSAPI 12","sndcpxid.nsapi12", FT_UINT8, BASE_DEC, NULL, 0x10, "Data", HFILL}},
 781                 {&hf_element_applicable_nsapi_11,
 782                                 { "NSAPI 11","sndcpxid.nsapi11", FT_UINT8, BASE_DEC, NULL, 0x08, "Data", HFILL}},
 783                 {&hf_element_applicable_nsapi_10,
 784                                 { "NSAPI 10","sndcpxid.nsapi10", FT_UINT8, BASE_DEC, NULL, 0x04, "Data", HFILL}},
 785                 {&hf_element_applicable_nsapi_9,
 786                                 { "NSAPI 9","sndcpxid.nsapi9", FT_UINT8, BASE_DEC, NULL, 0x02, "Data", HFILL}},
 787                 {&hf_element_applicable_nsapi_8,
 788                                 { "NSAPI 8","sndcpxid.nsapi8", FT_UINT8, BASE_DEC, NULL, 0x01, "Data", HFILL}},
 789                 {&hf_element_applicable_nsapi_7,
 790                                 { "NSAPI 7","sndcpxid.nsapi7", FT_UINT8, BASE_DEC, NULL, 0x80, "Data", HFILL}},
 791                 {&hf_element_applicable_nsapi_6,
 792                                 { "NSAPI 6","sndcpxid.nsapi6", FT_UINT8, BASE_DEC, NULL, 0x40, "Data", HFILL}},
 793                 {&hf_element_applicable_nsapi_5,
 794                                 { "NSAPI 5","sndcpxid.nsapi5", FT_UINT8, BASE_DEC, NULL, 0x20, "Data", HFILL}},
 795                 {&hf_element_applicable_nsapi_spare,
 796                                 { "Spare","sndcpxid.spare", FT_UINT8, BASE_DEC, NULL, 0x1F, "Ignore", HFILL}},
 797                 {&hf_sndcp_xid_rfc1144_s0,
 798                                 { "S0 - 1","sndcpxid.rfc1144_s0", FT_UINT8, BASE_DEC, NULL, 0xFF, "Data", HFILL}},
 799                 {&hf_sndcp_xid_rfc2507_f_max_period_msb,
 800                                 { "F Max Period MSB","sndcpxid.rfc2507_f_max_period_msb", FT_UINT8, BASE_HEX, NULL, 0xFF, "Data", HFILL}},
 801                 {&hf_sndcp_xid_rfc2507_f_max_period_lsb,
 802                                 { "F Max Period LSB","sndcpxid.rfc2507_f_max_period_lsb", FT_UINT8, BASE_HEX, NULL, 0xFF, "Data", HFILL}},
 803                 {&hf_sndcp_xid_rfc2507_f_max_time,
 804                                 { "F Max Time","sndcpxid.rfc2507_f_max_time", FT_UINT8, BASE_DEC, NULL, 0xFF, "Data", HFILL}},
 805                 {&hf_sndcp_xid_rfc2507_max_header,
 806                                 { "Max Header","sndcpxid.rfc2507_max_header", FT_UINT8, BASE_DEC, NULL, 0xFF, "Data", HFILL}},
 807                 {&hf_sndcp_xid_rfc2507_tcp_space,
 808                                 { "TCP Space","sndcpxid.rfc2507_max_tcp_space", FT_UINT8, BASE_DEC, NULL, 0xFF, "Data", HFILL}},
 809                 {&hf_sndcp_xid_rfc2507_non_tcp_space_msb,
 810                                 { "TCP non space MSB","sndcpxid.rfc2507_max_non_tcp_space_msb", FT_UINT8, BASE_HEX, NULL, 0xFF, "Data", HFILL}},
 811                 {&hf_sndcp_xid_rfc2507_non_tcp_space_lsb,
 812                                 { "TCP non space LSB","sndcpxid.rfc2507_max_non_tcp_space_lsb", FT_UINT8, BASE_HEX, NULL, 0xFF, "Data", HFILL}},
 813                 {&hf_sndcp_xid_rohc_max_cid_spare,
 814                                 { "Spare","sndcpxid.rohc_max_cid_spare", FT_UINT8, BASE_DEC, NULL, 0xC0, "Ignore", HFILL}},
 815                 {&hf_sndcp_xid_rohc_max_cid_msb,
 816                                 { "Max CID MSB","sndcpxid.rohc_max_cid_msb", FT_UINT8, BASE_HEX, NULL, 0x3F, "Data", HFILL}},
 817                 {&hf_sndcp_xid_rohc_max_cid_lsb,
 818                                 { "Max CID LSB","sndcpxid.rohc_max_cid_lsb", FT_UINT8, BASE_HEX, NULL, 0xFF, "Data", HFILL}},
 819                 {&hf_sndcp_xid_rohc_max_header,
 820                                 { "Max header","sndcpxid.rohc_max_header", FT_UINT8, BASE_DEC, NULL, 0xFF, "Data", HFILL}},
 821                 {&hf_sndcp_xid_rohc_profile_msb,
 822                                 { "Profile MSB","sndcpxid.rohc_profile_msb", FT_UINT8, BASE_HEX, NULL, 0xFF, "Data", HFILL}},
 823                 {&hf_sndcp_xid_rohc_profile_lsb,
 824                                 { "Profile LSB","sndcpxid.rohc_profile_lsb", FT_UINT8, BASE_HEX, NULL, 0xFF, "Data", HFILL}},
 825                 {&hf_sndcp_xid_V42bis_p0_spare,
 826                                 { "Spare","sndcpxid.V42bis_p0spare", FT_UINT8, BASE_DEC, NULL, 0xFC, "Ignore", HFILL}},
 827                 {&hf_sndcp_xid_V42bis_p0,
 828                                 { "P0","sndcpxid.V42bis_p0", FT_UINT8, BASE_HEX, NULL, 0x03, "Data", HFILL}},
 829                 {&hf_sndcp_xid_V42bis_p1_msb,
 830                                 { "P1 MSB","sndcpxid.V42bis_p1_msb", FT_UINT8, BASE_HEX, NULL, 0xFF, "Data", HFILL}},
 831                 {&hf_sndcp_xid_V42bis_p1_lsb,
 832                                 { "P1 LSB","sndcpxid.V42bis_p1_lsb", FT_UINT8, BASE_HEX, NULL, 0xFF, "Data", HFILL}},
 833                 {&hf_sndcp_xid_V42bis_p2,
 834                                 { "P2","sndcpxid.V42bis_p2", FT_UINT8, BASE_HEX, NULL, 0xFF, "Data", HFILL}},
 835                 {&hf_sndcp_xid_V44_c0_spare,
 836                                 { "P2","sndcpxid.V44_c0_spare", FT_UINT8, BASE_HEX, NULL, 0x3F, "Ignore", HFILL}},
 837                 {&hf_sndcp_xid_V44_c0,
 838                                 { "P2","sndcpxid.V44_c0", FT_UINT8, BASE_HEX, NULL, 0xC0, "Data", HFILL}},
 839                 {&hf_sndcp_xid_V44_p0_spare,
 840                                 { "Spare","sndcpxid.V44_p0spare", FT_UINT8, BASE_DEC, NULL, 0xFC, "Ignore", HFILL}},
 841                 {&hf_sndcp_xid_V44_p0,
 842                                 { "P0","sndcpxid.V44_p0", FT_UINT8, BASE_HEX, NULL, 0x03, "Data", HFILL}},
 843                 {&hf_sndcp_xid_V44_p1t_msb,
 844                                 { "P1t MSB","sndcpxid.V44_p1t_msb", FT_UINT8, BASE_HEX, NULL, 0xFF, "Data", HFILL}},
 845                 {&hf_sndcp_xid_V44_p1t_lsb,
 846                                 { "P1t LSB","sndcpxid.V44_p1t_lsb", FT_UINT8, BASE_HEX, NULL, 0xFF, "Data", HFILL}},
 847                 {&hf_sndcp_xid_V44_p1r_msb,
 848                                 { "P1r MSB","sndcpxid.V44_p1r_msb", FT_UINT8, BASE_HEX, NULL, 0xFF, "Data", HFILL}},
 849                 {&hf_sndcp_xid_V44_p1r_lsb,
 850                                 { "P1r LSB","sndcpxid.V44_p1r_lsb", FT_UINT8, BASE_HEX, NULL, 0xFF, "Data", HFILL}},
 851                 {&hf_sndcp_xid_V44_p3t_msb,
 852                                 { "P3t MSB","sndcpxid.V44_p3t_msb", FT_UINT8, BASE_HEX, NULL, 0xFF, "Data", HFILL}},
 853                 {&hf_sndcp_xid_V44_p3t_lsb,
 854                                 { "P3t LSB","sndcpxid.V44_p3t_lsb", FT_UINT8, BASE_HEX, NULL, 0xFF, "Data", HFILL}},
 855                 {&hf_sndcp_xid_V44_p3r_msb,
 856                                 { "P3r MSB","sndcpxid.V44_p3r_msb", FT_UINT8, BASE_HEX, NULL, 0xFF, "Data", HFILL}},
 857                 {&hf_sndcp_xid_V44_p3r_lsb,
 858                                 { "P3r LSB","sndcpxid.V44_p3r_lsb", FT_UINT8, BASE_HEX, NULL, 0xFF, "Data", HFILL}},
 859         };
 860
 861    /* Setup protocol subtree array */
 862   static gint *ett[] = {
 863     &ett_sndcp_xid,
 864     &ett_sndcp_xid_version_field,
 865     &ett_sndcp_comp_field
 866   };
 867
 868   /* Register the protocol name and description */
 869   proto_sndcp_xid = proto_register_protocol("Subnetwork Dependent Convergence Protocol XID",
 870                                         "SNDCP XID", "sndcpxid");
 871
 872   /* Required function calls to register the header fields and subtrees used */
 873   proto_register_field_array(proto_sndcp_xid, hf, array_length(hf));
 874   proto_register_subtree_array(ett, array_length(ett));
 875   register_dissector("sndcpxid", dissect_sndcp_xid, proto_sndcp_xid);
 876 }
 877
 878 /* If this dissector uses sub-dissector registration add a registration routine.
 879    This format is required because a script is used to find these routines and
 880    create the code that calls these routines.
 881 */
 882 void
 883 proto_reg_handoff_sndcp_xid(void)
 884 {
 885 }