epan/dissectors/packet-pw-atm.c

   1 /* packet-pw-atm.c
   2  * Routines for ATM PW dissection: it should be conform to RFC 4717.
   3  *
   4  * Copyright 2009 _FF_, _ATA_
   5  *
   6  * Francesco Fondelli <francesco dot fondelli, gmail dot com>
   7  * Artem Tamazov <artem [dot] tamazov [at] tellabs [dot] com>
   8  *
   9  * $Id$
  10  *
  11  * Wireshark - Network traffic analyzer
  12  * By Gerald Combs <gerald@wireshark.org>
  13  * Copyright 1998 Gerald Combs
  14  *
  15  * This program is free software; you can redistribute it and/or
  16  * modify it under the terms of the GNU General Public License
  17  * as published by the Free Software Foundation; either version 2
  18  * of the License, or (at your option) any later version.
  19  *
  20  * This program is distributed in the hope that it will be useful,
  21  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  22  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  23  * GNU General Public License for more details.
  24  *
  25  * You should have received a copy of the GNU General Public License
  26  * along with this program; if not, write to the Free Software
  27  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  28  */
  29
  30 /*
  31     DONE:
  32         - ATM N-to-One Cell Mode (with CW)
  33         - ATM N-to-One Cell Mode (no CW)
  34         - ATM One-to-One Cell Mode
  35         - ATM AAL5 SDU Mode
  36         - ATM AAL5 PDU Mode
  37 */
  38
  39 #ifdef HAVE_CONFIG_H
  40 # include "config.h"
  41 #endif
  42
  43 #include <stdio.h>
  44 #include <stdlib.h>
  45 #include <string.h>
  46 #include <glib.h>
  47 #include <epan/packet.h>
  48 #include <epan/expert.h>
  49 #include <epan/prefs.h>
  50
  51 #include <wiretap/wtap.h> /*for atm pseudo header*/
  52 #include "packet-mpls.h"
  53 #include "packet-atm.h"
  54 #include "packet-pw-atm.h"
  55 #include "packet-pw-common.h"
  56
  57 static gint proto_n1_nocw = -1;
  58 static gint proto_n1_cw = -1;
  59 static gint proto_11_or_aal5_pdu = -1;
  60 static gint proto_aal5_sdu = -1;
  61 /* subordinate dissectors: */
  62 static gint proto_control_word = -1;
  63 static gint proto_cell_header = -1;
  64 static gint proto_cell = -1;
  65
  66 static gint ett_encaps = -1;
  67 static gint ett_cw = -1;
  68 static gint ett_cell_header = -1;
  69 static gint ett_cell = -1;
  70
  71 static int hf_pw_type_n1_cw = -1;
  72 static int hf_pw_type_n1_nocw = -1;
  73 static int hf_pw_type_11_vcc = -1;
  74 static int hf_pw_type_11_vpc = -1;
  75 static int hf_pw_type_aal5_sdu = -1;
  76 static int hf_pw_type_aal5_pdu = -1;
  77
  78 static int hf_cell_h_vpi = -1;
  79 static int hf_cell_h_vci = -1;
  80 static int hf_cell_h_pti = -1;
  81 static int hf_cell_h_clp = -1;
  82 static int hf_cell_h_m = -1;
  83 static int hf_cell_h_v = -1;
  84 static int hf_cell_h_rsv = -1;
  85 static int hf_aal5_pdu_rsv = -1;
  86 static int hf_aal5_pdu_u = -1;
  87 static int hf_aal5_pdu_e = -1;
  88
  89 static int hf_cw_bits03 = -1;
  90 static int hf_pref_cw_rsv = -1;
  91 static int hf_generic_cw_rsv = -1;
  92 static int hf_pref_cw_flags = -1;
  93 static int hf_pref_cw_a5s_t = -1;
  94 static int hf_pref_cw_a5s_e = -1;
  95 static int hf_pref_cw_a5s_c = -1;
  96 static int hf_pref_cw_a5s_u = -1;
  97 static int hf_pref_cw_len = -1;
  98 static int hf_pref_cw_rsvlen = -1;
  99 static int hf_cw_seq = -1;
 100 static int hf_n1_cw_ncells = -1;
 101 static int hf_n1_nocw_ncells = -1;
 102 static int hf_11_ncells = -1;
 103 static int hf_gen_cw_atmbyte = -1;
 104 static int hf_cell_payload_len = -1;
 105
 106 static dissector_handle_t dh_cell;
 107 static dissector_handle_t dh_cell_header;
 108 static dissector_handle_t dh_control_word;
 109 static dissector_handle_t dh_atm_truncated;
 110 static dissector_handle_t dh_atm_untruncated;
 111 static dissector_handle_t dh_atm_oam_cell;
 112 static dissector_handle_t dh_padding;
 113 static dissector_handle_t dh_data;
 114
 115 #define PTI_IS_ADMIN(pti) ((pti) == 4 || (pti) == 5 || (pti) == 6)  /*see atm_pt_vals[]*/
 116
 117 #define MODE_11(mode)                   (PWATM_MODE_11_VCC == (mode) || PWATM_MODE_11_VPC == (mode))
 118 #define MODE_N1(mode)                   (PWATM_MODE_N1_NOCW == (mode)|| PWATM_MODE_N1_CW == (mode))
 119 #define MODE_11_OR_AAL5_PDU(mode)       (MODE_11(mode) || PWATM_MODE_AAL5_PDU == (mode))
 120
 121 #define VALUE_SELECTOR_VPC_VCC_PDU(mode,val_vpc,val_vcc,val_pdu)\
 122         ((PWATM_MODE_11_VPC == (mode))                          \
 123                 ? (val_vpc)                                     \
 124                 : ((PWATM_MODE_11_VCC == (mode))                \
 125                         ? (val_vcc)                             \
 126                         : ((PWATM_MODE_AAL5_PDU == (mode))      \
 127                                 ? (val_pdu)                     \
 128                                 : 0                             \
 129                           )                                     \
 130                   )                                             \
 131         )
 132
 133 #define UPDATE_CUMULATIVE_VALUE(cumulative_val,new_val)\
 134         do\
 135         {\
 136                 if (-2 >= (cumulative_val))\
 137                 {\
 138                 }\
 139                 else if (-1 == (cumulative_val))\
 140                 {\
 141                         (cumulative_val) = (new_val);\
 142                 }\
 143                 else if ((new_val) != (cumulative_val))\
 144                 {\
 145                         (cumulative_val) = -2;\
 146                 }\
 147         }\
 148         while(0)
 149
 150 #define SIZEOF_ATM_CELL_PAYLOAD 48
 151 #define SIZEOF_N1_PW_CELL_HEADER 4
 152 #define SIZEOF_11_VCC_PW_CELL_HEADER 1
 153 #define SIZEOF_11_VPC_PW_CELL_HEADER 3
 154 #define SIZEOF_N1_PW_CELL       (SIZEOF_ATM_CELL_PAYLOAD+SIZEOF_N1_PW_CELL_HEADER)
 155 #define SIZEOF_11_VCC_PW_CELL   (SIZEOF_ATM_CELL_PAYLOAD+SIZEOF_11_VCC_PW_CELL_HEADER)
 156 #define SIZEOF_11_VPC_PW_CELL   (SIZEOF_ATM_CELL_PAYLOAD+SIZEOF_11_VPC_PW_CELL_HEADER)
 157
 158 const char pwc_longname_pw_atm_n1_cw[] = "MPLS PW ATM N-to-One encapsulation, with CW";
 159 const char pwc_longname_pw_atm_n1_nocw[] = "MPLS PW ATM N-to-One encapsulation, no CW";
 160 const char pwc_longname_pw_atm_11_or_aal5_pdu[] = "MPLS PW ATM One-to-One or AAL5 PDU encapsulation";
 161 const char pwc_longname_pw_atm_aal5_sdu[] = "MPLS PW ATM AAL5 CPCS-SDU mode encapsulation";
 162
 163 static const char longname_pw_atm_11_vcc[] = "MPLS PW ATM One-to-One VCC Cell Transport";
 164 static const char longname_pw_atm_11_vpc[] = "MPLS PW ATM One-to-One VPC Cell Transport";
 165 static const char longname_pw_atm_aal5_pdu[] = "MPLS PW ATM AAL5 PDU encapsulation";
 166
 167 static const char shortname_n1_cw[] = "MPLS PW ATM N:1 CW";
 168 static const char shortname_n1_nocw[] = "MPLS PW ATM N:1 no CW";
 169 static const char shortname_11_or_aal5_pdu[] = "MPLS PW ATM 1:1 / AAL5 PDU";
 170 static const char shortname_11_vpc[] = "MPLS PW ATM 1:1 VPC";
 171 static const char shortname_11_vcc[] = "MPLS PW ATM 1:1 VCC";
 172 static const char shortname_aal5_sdu[] = "MPLS PW ATM AAL5 SDU";
 173 static const char shortname_aal5_pdu[] = "MPLS PW ATM AAL5 PDU";
 174
 175 /*
 176  * These options are needed to support Nokia AXE and stuff alike.
 177  * Note that these options will affect PW type auto-guessing, if such heuristic
 178  * implemented in the future.
 179  */
 180 static gboolean pref_n1_cw_allow_cw_length_nonzero      = FALSE;
 181 static gboolean pref_n1_cw_extend_cw_length_with_rsvd   = FALSE;
 182 static gboolean pref_aal5_sdu_allow_cw_length_nonzero   = FALSE;
 183 static gboolean pref_aal5_sdu_extend_cw_length_with_rsvd= FALSE;
 184
 185
 186 static
 187 int pw_cell_size(const pwatm_mode_t mode, const pwatm_submode_t submode)
 188 {
 189         switch(mode)
 190         {
 191         case PWATM_MODE_N1_NOCW:
 192         case PWATM_MODE_N1_CW:
 193                 return SIZEOF_N1_PW_CELL;
 194         case PWATM_MODE_11_VCC:
 195                 return SIZEOF_11_VCC_PW_CELL;
 196         case PWATM_MODE_11_VPC:
 197                 return SIZEOF_11_VPC_PW_CELL;
 198         case PWATM_MODE_AAL5_PDU:
 199                 /* AAL5 PDU size is n*48 bytes */
 200                 return SIZEOF_ATM_CELL_PAYLOAD;
 201         case PWATM_MODE_AAL5_SDU:
 202                 if (PWATM_SUBMODE_ADMIN_CELL == submode)
 203                 {
 204                         return SIZEOF_N1_PW_CELL; /*n:1 encapsulation is used for admin cells*/
 205                 }
 206                 else
 207                 {
 208                         DISSECTOR_ASSERT_NOT_REACHED();
 209                         return 0;
 210                 }
 211         default:
 212                 DISSECTOR_ASSERT_NOT_REACHED();
 213                 return 0;
 214         }
 215 }
 216
 217 static
 218 int pw_cell_header_size(const pwatm_mode_t mode, const pwatm_submode_t submode)
 219 {
 220         switch(mode)
 221         {
 222         case PWATM_MODE_N1_NOCW:
 223         case PWATM_MODE_N1_CW:
 224                 return SIZEOF_N1_PW_CELL_HEADER;
 225         case PWATM_MODE_11_VCC:
 226                 return SIZEOF_11_VCC_PW_CELL_HEADER;
 227         case PWATM_MODE_11_VPC:
 228                 return SIZEOF_11_VPC_PW_CELL_HEADER;
 229         case PWATM_MODE_AAL5_SDU:
 230                 if (PWATM_SUBMODE_ADMIN_CELL == submode)
 231                 {
 232                         return SIZEOF_N1_PW_CELL_HEADER; /*n:1 encapsulation is used for admin cells*/
 233                 }
 234                 else
 235                 {
 236                         DISSECTOR_ASSERT_NOT_REACHED();
 237                         return 0;
 238                 }
 239         case PWATM_MODE_AAL5_PDU: /*not applicable*/
 240         default:
 241                 DISSECTOR_ASSERT_NOT_REACHED();
 242                 return 0;
 243         }
 244 }
 245
 246 static
 247 int number_of_cells(const pwatm_mode_t mode
 248                 ,const pwatm_submode_t submode
 249                 ,const gint payload_size
 250                 ,gint* const remainder_size)
 251 {
 252         int cells;
 253
 254         DISSECTOR_ASSERT(payload_size >= 0);
 255
 256         switch(mode)
 257         {
 258         case PWATM_MODE_N1_NOCW:
 259         case PWATM_MODE_N1_CW:
 260         case PWATM_MODE_11_VCC:
 261         case PWATM_MODE_11_VPC:
 262         case PWATM_MODE_AAL5_PDU:
 263                 cells = payload_size / pw_cell_size(mode,submode);
 264                 *remainder_size = payload_size - (cells * pw_cell_size(mode,submode));
 265                 return cells;
 266         case PWATM_MODE_AAL5_SDU:
 267                 if (PWATM_SUBMODE_ADMIN_CELL == submode)
 268                 {
 269                         cells = payload_size / pw_cell_size(mode,submode);
 270                         if (cells > 1) cells = 1; /*max. 1 admin cell may be present in aal5 sdu mode */
 271                         *remainder_size = payload_size - (cells * pw_cell_size(mode,submode));
 272                         return cells;
 273                 }
 274                 else
 275                 {
 276                         /*not applicable*/
 277                 }
 278                 /*fallthrough*/
 279         default:
 280                 DISSECTOR_ASSERT_NOT_REACHED();
 281                 *remainder_size = payload_size;
 282                 return 0;
 283         }
 284
 285 }
 286
 287
 288 static
 289 void col_append_pw_info(packet_info * pinfo
 290         ,const int payload_size
 291         ,const int cells
 292         ,const int padding_size)
 293 {
 294         pwatm_private_data_t* pd;
 295         DISSECTOR_ASSERT(pinfo != NULL);
 296
 297         pd = pinfo->private_data;
 298         DISSECTOR_ASSERT(pd != NULL);
 299
 300         if (pd->props & PWC_ANYOF_CW_BAD)
 301         {
 302                 col_append_str(pinfo->cinfo, COL_INFO, "CW:Bad");
 303         }
 304
 305         if (pd->props & PWC_PAY_SIZE_BAD)
 306         {
 307                 if (pd->props & PWC_ANYOF_CW_BAD)
 308                 {
 309                         col_append_str(pinfo->cinfo, COL_INFO, ", ");
 310                 }
 311                 col_append_str(pinfo->cinfo, COL_INFO, "Payload size:Bad, ");
 312                 col_append_fstr(pinfo->cinfo, COL_INFO, "%d byte%s"
 313                         ,(int)payload_size
 314                         ,plurality(payload_size,"","s"));
 315         }
 316
 317         if (pd->props == 0) /*omit "atm cells" etc if something is wrong*/
 318         {
 319                 /* number of cells may be not known */
 320                 if (cells >=0)
 321                         col_append_fstr(pinfo->cinfo, COL_INFO, "%d ATM cell%s"
 322                                 ,cells
 323                                 ,plurality(cells,"","s"));
 324                 /*
 325                  * Display ATM-specific attributes which are the same
 326                  * across all the cells in the pw packet.
 327                  * Meanings of values:
 328                  *   (-1) unknown - not displayed,
 329                  *   (-2) "not the same in all cells" - not displayed
 330                  *   positive values - ok, displayed
 331                  */
 332                 if (pd->cumulative.vpi >= 0)
 333                         col_append_fstr(pinfo->cinfo, COL_INFO, ", VPI:%.4d", pd->cumulative.vpi);
 334                 if (pd->cumulative.vci >= 0)
 335                         col_append_fstr(pinfo->cinfo, COL_INFO, ", VCI:%.5d", pd->cumulative.vci);
 336                 if (pd->cumulative.pti >= 0)
 337                         col_append_fstr(pinfo->cinfo, COL_INFO, ", PTI:%.1d", pd->cumulative.pti);
 338                 if (pd->cumulative.clp >= 0)
 339                         col_append_fstr(pinfo->cinfo, COL_INFO, ", CLP:%.1d", pd->cumulative.clp);
 340         }
 341
 342         if (padding_size != 0)
 343         {
 344                 col_append_fstr(pinfo->cinfo, COL_INFO, ", %d padding"
 345                         ,(int)padding_size);
 346         }
 347 }
 348
 349
 350 static
 351 void prepare_pseudo_header_atm(
 352         union wtap_pseudo_header * const ph,
 353         const pwatm_private_data_t * const pdata,
 354         const unsigned aal)
 355 {
 356         DISSECTOR_ASSERT(NULL != pdata);
 357         DISSECTOR_ASSERT(NULL != ph);
 358
 359         memset(ph,0,sizeof(*ph)); /* it is OK to clear unknown values */
 360         ph->atm.flags           = 0; /* status flags */
 361         ph->atm.aal             = aal;
 362         ph->atm.type            = TRAF_UNKNOWN;
 363         ph->atm.subtype         = TRAF_ST_UNKNOWN;
 364         ph->atm.vpi             = (pdata->vpi >= 0) ? pdata->vpi : 0 /*unknown*/;
 365         ph->atm.vci             = (pdata->vci >= 0) ? pdata->vci : 0 /*unknown*/;
 366         ph->atm.aal2_cid        = 0; /*not applicable*//* channel id */
 367         ph->atm.channel         = 0; /*unknown*//* link: 0 for DTE->DCE, 1 for DCE->DTE */
 368         ph->atm.cells           = 0; /*zero indicates that we do not have trailer info*/
 369         /*user-to-user indicator & CPI*/
 370         ph->atm.aal5t_u2u       = 0; /* all bits unknown except lsb of UU */
 371         if (pdata->aal5_sdu_frame_relay_cr_bit)
 372         { /* Let's give Frame Relay C/R bit to ATM dissector.*/
 373                 ph->atm.aal5t_u2u |= (1<<8); /*UU octet is at << 8 in aal5t_u2u*/
 374         }
 375         ph->atm.aal5t_len       = 0; /*unknown*//* length of the packet from trailer*/
 376         ph->atm.aal5t_chksum    = 0; /*unknown*//* checksum for AAL5 packet from trailer */
 377         return;
 378 }
 379
 380
 381 static
 382 void dissect_payload_and_padding(
 383         tvbuff_t * tvb
 384         ,packet_info * pinfo
 385         ,proto_tree * tree
 386         ,const gint payload_size
 387         ,const gint padding_size)
 388 {
 389         int dissected;
 390         tvbuff_t* tvb_2;
 391         pwatm_private_data_t* pd;
 392
 393         DISSECTOR_ASSERT(NULL != pinfo);
 394         pd = pinfo->private_data;
 395         DISSECTOR_ASSERT(NULL != pd);
 396
 397         for(dissected = 0, pd->pw_cell_number = 0;
 398                 payload_size > dissected;
 399                 ++(pd->pw_cell_number))
 400         {
 401                 tvb_2 = tvb_new_subset_remaining(tvb,dissected);
 402                 dissected += call_dissector(dh_cell_header, tvb_2, pinfo, tree);
 403
 404                 tvb_2 = tvb_new_subset_remaining(tvb,dissected);
 405
 406                 /*dissect as oam for specific vci/pti, just like atm dissector does*/
 407                 if (pd->vci >= 0 && pd->pti >=0)
 408                 {
 409                         if (atm_is_oam_cell(pd->vci,pd->pti))
 410                         {
 411                                 pd->cell_mode_oam = TRUE;
 412                         }
 413                 }
 414
 415                 if (pd->cell_mode_oam)
 416                 {
 417                         union wtap_pseudo_header* pseudo_header_save;
 418                         union wtap_pseudo_header ph;
 419                         tvbuff_t* tvb_3;
 420                         int bytes_to_dissect;
 421                         /* prepare buffer for old-style dissector */
 422                         /* oam cell is always 48 bytes, but payload_size maybe too small */
 423                         if ((payload_size - dissected) >= SIZEOF_ATM_CELL_PAYLOAD)
 424                                 bytes_to_dissect = SIZEOF_ATM_CELL_PAYLOAD;
 425                         else
 426                                 bytes_to_dissect = (payload_size - dissected);
 427                         tvb_3 = tvb_new_subset(tvb_2,0,bytes_to_dissect,-1);
 428                         /*aal5_sdu: disable filling columns after 1st (valid) oam cell*/
 429                         if (pd->mode == PWATM_MODE_AAL5_SDU && pd->pw_cell_number > 0)
 430                         {
 431                                 pd->enable_fill_columns_by_atm_dissector = FALSE;
 432                         }
 433                         /* save & prepare new pseudo header for atm aal5 decoding */
 434                         pseudo_header_save = pinfo->pseudo_header;
 435                         pinfo->pseudo_header = &ph;
 436                         prepare_pseudo_header_atm(&ph,pd,AAL_OAMCELL);
 437
 438                         call_dissector(dh_atm_oam_cell, tvb_3, pinfo, tree);
 439                         dissected += bytes_to_dissect;
 440                         /* restore pseudo header */
 441                         pinfo->pseudo_header = pseudo_header_save;
 442                 }
 443                 else
 444                 {
 445                         dissected += call_dissector(dh_cell, tvb_2, pinfo, tree);
 446                 }
 447         }
 448
 449         if (padding_size != 0)
 450         {
 451                 tvbuff_t* tvb_2;
 452                 tvb_2 = tvb_new_subset(tvb
 453                                 ,(tvb_reported_length_remaining(tvb, 0) - padding_size)
 454                                 ,-1
 455                                 ,-1);
 456                 call_dissector(dh_padding, tvb_2, pinfo, tree);
 457         }
 458         return;
 459 }
 460
 461
 462 static
 463 gboolean too_small_packet_or_notpw(tvbuff_t * tvb
 464         ,packet_info * pinfo
 465         ,proto_tree * tree
 466         ,const int proto_handler
 467         ,const char * const proto_name_column)
 468 {
 469         gint packet_size;
 470         packet_size = tvb_reported_length_remaining(tvb, 0);
 471         /*
 472          * FIXME
 473          * "4" below should be replaced by something like "min_packet_size_this_dissector"
 474          * Also call to dissect_try_cw_first_nibble() should be moved before this block
 475          */
 476         if (packet_size < 4) /* 4 is smallest size which may be sensible (for PWACH dissector) */
 477         {
 478                 if (tree)
 479                 {
 480                         proto_item  *item;
 481                         item = proto_tree_add_item(tree, proto_handler, tvb, 0, -1, FALSE);
 482                         expert_add_info_format(pinfo, item, PI_MALFORMED, PI_ERROR,
 483                                 "PW packet size (%d) is too small to carry sensible information"
 484                                 ,(int)packet_size);
 485                 }
 486                 /* represent problems in the Packet List pane */
 487                 if (check_col(pinfo->cinfo, COL_PROTOCOL))
 488                 {
 489                         col_set_str(pinfo->cinfo, COL_PROTOCOL, proto_name_column);
 490                 }
 491                 col_set_str(pinfo->cinfo, COL_INFO, "Malformed: PW packet is too small");
 492                 return TRUE;
 493         }
 494         if (dissect_try_cw_first_nibble(tvb, pinfo, tree))
 495         {
 496                 return TRUE;
 497         }
 498         return FALSE;
 499 }
 500
 501
 502 /*
 503  * NOTE. RFC describes ATM-specific byte in a cumbersome way.
 504  * It is a part of CW, but at the same time, it must be repeated
 505  * with each cell, _except_ first.
 506  *
 507  * Alternatively, ATM-specific byte may be considered as part of
 508  * PW payload (i.e., as part of pw atm cell header), so we can say that
 509  * it is being repeated with each cell.
 510  *
 511  * This dissector is written according to the latter consideration.
 512  */
 513 static
 514 void dissect_11_or_aal5_pdu(tvbuff_t * tvb, packet_info * pinfo, proto_tree * tree)
 515 {
 516         const char *proto_name_column;
 517         const char *proto_name_tree = NULL;
 518         gint payload_size;
 519         int cells;
 520         pwatm_private_data_t pd = PWATM_PRIVATE_DATA_T_INITIALIZER;
 521         void * pd_save = pinfo->private_data;
 522         pinfo->private_data = &pd;
 523
 524         proto_name_column = &shortname_11_or_aal5_pdu[0];
 525         if (too_small_packet_or_notpw(tvb,pinfo,tree,proto_11_or_aal5_pdu,proto_name_column))
 526         {
 527                 return;
 528         }
 529         pd.packet_size = tvb_reported_length_remaining(tvb, 0);
 530
 531         /*
 532          * Guess encapsulation mode according to M & V bits from the 3rd byte of CW.
 533          * Also adjust protocol name strings.
 534          */
 535         {
 536                 guint8 third_byte;
 537                 third_byte = tvb_get_guint8(tvb, 3);
 538                 if (0 == (third_byte & 0x80 /*generic_cw.m*/))
 539                 { /*1:1 modes*/
 540                         if (0 != (third_byte & 0x40 /*generic_cw.v*/))
 541                         {
 542                                 pd.mode = PWATM_MODE_11_VPC;
 543                                 proto_name_column = &shortname_11_vpc[0];
 544                                 proto_name_tree = &longname_pw_atm_11_vpc[0];
 545                         }
 546                         else
 547                         {
 548                                 pd.mode = PWATM_MODE_11_VCC;
 549                                 proto_name_column = &shortname_11_vcc[0];
 550                                 proto_name_tree = &longname_pw_atm_11_vcc[0];
 551                         }
 552                 }
 553                 else
 554                 {
 555                         pd.mode = PWATM_MODE_AAL5_PDU;
 556                         proto_name_column = &shortname_aal5_pdu[0];
 557                         proto_name_tree = &longname_pw_atm_aal5_pdu[0];
 558                 }
 559         }
 560
 561
 562         /* check how "good" is this packet */
 563         pd.props = PWC_PACKET_PROPERTIES_T_INITIALIZER;
 564         if (0 != (tvb_get_guint8(tvb, 0) & 0xf0 /*bits03*/))
 565         {
 566                 pd.props |= PWC_CW_BAD_BITS03;
 567         }
 568         if (0 != (tvb_get_guint8(tvb, 0) & 0x0f /*generic_cw.rsvd*/))
 569         {
 570                 pd.props |= PWC_CW_BAD_RSV;
 571         }
 572
 573         /*
 574          * Do not dissect and validate atm-specific byte (3rd byte of CW).
 575          * It will be dissected/validated as pw cell header.
 576          */
 577
 578         /*
 579          * Decide about payload length and padding.
 580          *
 581          * Is padding allowed?
 582          *      eth header length  == 14
 583          *      mpls label length  ==  4
 584          *      cw length          ==  4
 585          *      min payload length == 48
 586          *      => 14 + 4 + 4 + 48 == 70
 587          *        => 70 >= 64
 588          *          => no padding allowed
 589          */
 590         if (MODE_11(pd.mode))
 591         {
 592                 gint bad_padding_size;
 593                 payload_size = pd.packet_size - (PWC_SIZEOF_CW-1);
 594                 cells = number_of_cells(pd.mode,pd.submode,payload_size,&bad_padding_size);
 595                 if (0 == cells || 0 != bad_padding_size)
 596                 {
 597                         pd.props |= PWC_PAY_SIZE_BAD;
 598                 }
 599         }
 600         else
 601         { /*aal5_pdu mode*/
 602                 gint bad_padding_size;
 603                 payload_size = pd.packet_size - PWC_SIZEOF_CW;
 604                 cells = number_of_cells(pd.mode,pd.submode,payload_size,&bad_padding_size);
 605                 /* at least 1 cell must be present in the packet in this mode*/
 606                 if (1 > cells || 0 != bad_padding_size)
 607                 {
 608                         pd.props |= PWC_PAY_SIZE_BAD;
 609                 }
 610                 cells = -1; /*this value not needed anymore, suppress pinting of it*/
 611         }
 612
 613         if (PWATM_MODE_AAL5_PDU == pd.mode)
 614         {
 615                 /* sub-dissectors _may_ overwrite columns in aal5_pdu mode */
 616                 if (check_col(pinfo->cinfo, COL_PROTOCOL))
 617                 {
 618                         col_set_str(pinfo->cinfo, COL_PROTOCOL, proto_name_column);
 619                 }
 620                 if (check_col(pinfo->cinfo, COL_INFO))
 621                 {
 622                         col_clear(pinfo->cinfo, COL_INFO);
 623                         col_append_pw_info(pinfo, payload_size, cells, 0);
 624                 }
 625         }
 626
 627         if (tree)
 628         {
 629                 proto_item* item;
 630                 item = proto_tree_add_item(tree, proto_11_or_aal5_pdu, tvb, 0, -1, FALSE);
 631                 /*overwrite heading line*/
 632                 proto_item_set_text(item, proto_name_tree, 0/*-warn gcc 3.4.4*/);
 633                 pwc_item_append_text_n_items(item,cells,"good ATM cell");
 634                 {
 635                         proto_tree* tree;
 636                         tree = proto_item_add_subtree(item, ett_encaps);
 637                         {
 638                                 proto_item* item;
 639                                 item = proto_tree_add_boolean(tree
 640                                         ,VALUE_SELECTOR_VPC_VCC_PDU(pd.mode
 641                                                 ,hf_pw_type_11_vpc
 642                                                 ,hf_pw_type_11_vcc
 643                                                 ,hf_pw_type_aal5_pdu)
 644                                         ,tvb, 0, 0, TRUE);
 645                                 PROTO_ITEM_SET_GENERATED(item);
 646                                 if (MODE_11(pd.mode))
 647                                 {
 648                                         item = proto_tree_add_int(tree, hf_11_ncells, tvb, 0, 0, cells);
 649                                         PROTO_ITEM_SET_GENERATED(item);
 650                                 }
 651                         }
 652                 }
 653                 if (pd.props & PWC_PAY_SIZE_BAD)
 654                 {
 655                         expert_add_info_format(pinfo, item, PI_MALFORMED, PI_ERROR
 656                                 ,"PW payload size (%d) must be <> 0 and multiple of %d"
 657                                 ,(int)payload_size,pw_cell_size(pd.mode,pd.submode));
 658                         if (payload_size != 0 && MODE_11(pd.mode))
 659                         {
 660                                 expert_add_info_format(pinfo, item, PI_MALFORMED, PI_NOTE,
 661                                         "PW ATM cell [%.3d] is broken",(int)cells);
 662                         }
 663                 }
 664         }
 665
 666         {
 667                 tvbuff_t* tvb_2;
 668                 tvb_2 = tvb_new_subset(tvb, 0, PWC_SIZEOF_CW, PWC_SIZEOF_CW);
 669                 call_dissector(dh_control_word, tvb_2, pinfo, tree);
 670
 671                 tvb_2 = tvb_new_subset(tvb, (PWC_SIZEOF_CW-1), -1, -1);
 672                 if (MODE_11(pd.mode))
 673                 {
 674                         dissect_payload_and_padding(tvb_2,pinfo,tree,payload_size,0);
 675                 }
 676                 else
 677                 { /*aal5_pdu mode*/
 678                         if (payload_size != 0)
 679                         {
 680                                 tvbuff_t* tvb_3;
 681                                 union wtap_pseudo_header* pseudo_header_save;
 682                                 union wtap_pseudo_header ph;
 683
 684                                 tvb_3 = tvb_new_subset_remaining(tvb_2, 1);
 685                                 /* prepare pseudo header for atm aal5 decoding */
 686                                 pseudo_header_save = pinfo->pseudo_header;
 687                                 pinfo->pseudo_header = &ph;
 688                                 prepare_pseudo_header_atm(&ph,&pd,AAL_5);
 689                                 call_dissector(dh_atm_untruncated, tvb_3, pinfo, tree);
 690                                 /* restore pseudo header */
 691                                 pinfo->pseudo_header = pseudo_header_save;
 692                         }
 693                 }
 694         }
 695
 696         if (MODE_11(pd.mode))
 697         {
 698                 /* overwrite everything written by sub-dissectors in 1:1 modes*/
 699                 if (check_col(pinfo->cinfo, COL_PROTOCOL))
 700                 {
 701                         col_set_str(pinfo->cinfo, COL_PROTOCOL, proto_name_column);
 702                 }
 703                 if (check_col(pinfo->cinfo, COL_INFO))
 704                 {
 705                         col_clear(pinfo->cinfo, COL_INFO);
 706                         col_append_pw_info(pinfo, payload_size, cells, 0);
 707                 }
 708         }
 709
 710         pinfo->private_data = pd_save;
 711         return;
 712 }
 713
 714
 715 static
 716 void dissect_aal5_sdu(tvbuff_t * tvb, packet_info * pinfo, proto_tree * tree)
 717 {
 718         const char *proto_name_column;
 719         gint payload_size;
 720         gint padding_size;
 721         int cells;
 722         pwatm_private_data_t pd = PWATM_PRIVATE_DATA_T_INITIALIZER;
 723         void * pd_save = pinfo->private_data;
 724
 725         pinfo->private_data = &pd;
 726         pd.mode = PWATM_MODE_AAL5_SDU;
 727
 728         proto_name_column = &shortname_aal5_sdu[0];
 729         if (too_small_packet_or_notpw(tvb,pinfo,tree,proto_aal5_sdu,proto_name_column))
 730         {
 731                 return;
 732         }
 733         pd.packet_size = tvb_reported_length_remaining(tvb, 0);
 734
 735         /* check how "good" is this packet */
 736         /* also decide payload length from packet size and CW */
 737         if (0 != (tvb_get_guint8(tvb, 0) & 0xf0 /*bits03*/))
 738         {
 739                 pd.props |= PWC_CW_BAD_BITS03;
 740         }
 741
 742         pd.submode = PWATM_SUBMODE_DEFAULT;
 743         if (0 != (tvb_get_guint8(tvb, 0) & 0x08 /*preferred_cw.T*/))
 744         {
 745                 pd.submode = PWATM_SUBMODE_ADMIN_CELL;
 746         }
 747
 748         if (! pref_aal5_sdu_extend_cw_length_with_rsvd)
 749         {
 750                 if (0 != (tvb_get_guint8(tvb, 1) & 0xc0 /*preferred_cw.rsvd*/))
 751                 {
 752                         pd.props |= PWC_CW_BAD_RSV;
 753                 }
 754         }
 755         {
 756                 /* RFC4717:
 757                  * [ If the packet's length (defined as the length of the layer 2 payload
 758                  * plus the length of the control word) is less than 64 bytes, the
 759                  * length field MUST be set to the packet's length.  Otherwise, the
 760                  * length field MUST be set to zero... Note that the length field
 761                  * is not used in the N-to-one mode and MUST be set to 0. ]
 762                  *
 763                  * Also we allow some "extensions"conducted by pref_xxx.
 764                  */
 765                 gint payload_size_from_packet;
 766                 int cw_len; /*length field from cw*/
 767
 768                 payload_size_from_packet = pd.packet_size - PWC_SIZEOF_CW;
 769                 if (pref_aal5_sdu_extend_cw_length_with_rsvd)
 770                 {
 771                         cw_len = tvb_get_guint8(tvb, 1) & 0xff;
 772                 }
 773                 else
 774                 {
 775                         cw_len = tvb_get_guint8(tvb, 1) & 0x3f;
 776                 }
 777
 778                 /*
 779                  * Initial assumptions: no padding,
 780                  * payload size derived from psn packet size.
 781                  */
 782                 payload_size = payload_size_from_packet;
 783                 padding_size = 0;
 784
 785                 if (0 == cw_len)
 786                 {
 787                         /*keep initial assumptions*/
 788                 }
 789                 else if (!pref_aal5_sdu_allow_cw_length_nonzero
 790                          && PWATM_SUBMODE_ADMIN_CELL == pd.submode)
 791                 {
 792                         /*
 793                          * The "allow CW.Length != 0" option affects
 794                          * ATM admin cell submode only, because this submode
 795                          * is equal to N:1 encapsulation.
 796                          * CW.Length !=0 is always OK for normal (AAL5 payload) submode.
 797                          */
 798                         pd.props |= PWC_CW_BAD_LEN_MUST_BE_0;
 799                 }
 800                 else
 801                 {
 802                         gint payload_size_from_cw;
 803                         payload_size_from_cw = cw_len - PWC_SIZEOF_CW;
 804                         if (payload_size_from_cw <= 0)
 805                         {
 806                                 pd.props |= PWC_CW_BAD_PAYLEN_LE_0;
 807                         }
 808                         else if (payload_size_from_cw > payload_size_from_packet)
 809                         {
 810                                 pd.props |= PWC_CW_BAD_PAYLEN_GT_PACKET;
 811                         }
 812                         else
 813                         {
 814
 815                                 payload_size = payload_size_from_cw;
 816                                 padding_size = payload_size_from_packet - payload_size_from_cw; /* >=0 */
 817                                 if (padding_size != 0)
 818                                 {
 819                                         /*
 820                                          * Padding is not allowed in ATM admin cell submode only,
 821                                          * because this submode is equal to N:1 encapsulation.
 822                                          * Padding is OK for normal (AAL5 payload) submode.
 823                                          */
 824                                         if (PWATM_SUBMODE_ADMIN_CELL == pd.submode)
 825                                         {
 826                                                 pd.props |= PWC_CW_BAD_PADDING_NE_0;
 827                                                 /*restore sizes*/
 828                                                 payload_size = payload_size_from_packet;
 829                                                 padding_size = 0;
 830                                         }
 831                                 }
 832                         }
 833                 }
 834
 835                 if (PWATM_SUBMODE_ADMIN_CELL == pd.submode)
 836                 {
 837                         gint bad_padding_size;
 838                         cells = number_of_cells(pd.mode,pd.submode,payload_size,&bad_padding_size);
 839                         /* only one atm admin cell is allowed in the packet in this mode*/
 840                         if (1 != cells || 0 != bad_padding_size)
 841                         {
 842                                 pd.props |= PWC_PAY_SIZE_BAD;
 843                         }
 844                 }
 845                 else
 846                 {
 847                         cells = -1; /*unknown*/
 848                         /* Any size is allowed for AAL5 SDU payload */
 849                 }
 850         }
 851
 852         /* fill columns in Packet List */
 853         if (check_col(pinfo->cinfo, COL_PROTOCOL))
 854         {
 855                 col_set_str(pinfo->cinfo, COL_PROTOCOL, proto_name_column);
 856                 if (PWATM_SUBMODE_ADMIN_CELL == pd.submode)
 857                 {
 858                         col_append_str(pinfo->cinfo, COL_PROTOCOL, ", OAM cell");
 859                 }
 860         }
 861
 862         if (check_col(pinfo->cinfo, COL_INFO))
 863         {
 864                 col_clear(pinfo->cinfo, COL_INFO);
 865                 col_append_pw_info(pinfo, payload_size, cells, padding_size);
 866         }
 867
 868         if (tree)
 869         {
 870                 proto_item* item;
 871                 item = proto_tree_add_item(tree, proto_aal5_sdu, tvb, 0, -1, FALSE);
 872                 {
 873                         proto_tree* tree;
 874                         tree = proto_item_add_subtree(item, ett_encaps);
 875                         {
 876                                 item = proto_tree_add_boolean(tree, hf_pw_type_aal5_sdu, tvb, 0, 0, TRUE);
 877                                 PROTO_ITEM_SET_GENERATED(item);
 878                         }
 879                 }
 880                 if (pd.props & PWC_PAY_SIZE_BAD)
 881                 {
 882                         DISSECTOR_ASSERT(PWATM_SUBMODE_ADMIN_CELL == pd.submode);
 883                         expert_add_info_format(pinfo, item, PI_MALFORMED ,PI_ERROR
 884                                 ,"In ATM admin cell mode,"
 885                                 " PW payload size (%d) must be == %d (exactly 1 admin cell)"
 886                                 ,(int)payload_size,(int)SIZEOF_N1_PW_CELL);
 887                 }
 888         }
 889
 890         {
 891                 tvbuff_t* tvb_2;
 892                 tvb_2 = tvb_new_subset(tvb, 0, PWC_SIZEOF_CW, PWC_SIZEOF_CW);
 893                 call_dissector(dh_control_word, tvb_2, pinfo, tree);
 894
 895                 tvb_2 = tvb_new_subset_remaining(tvb, PWC_SIZEOF_CW);
 896                 if (PWATM_SUBMODE_ADMIN_CELL == pd.submode)
 897                 {
 898                         dissect_payload_and_padding(tvb_2,pinfo,tree,payload_size,padding_size);
 899                 }
 900                 else /*AAL5 payload*/
 901                 {
 902                         if (payload_size != 0)
 903                         {
 904                                 tvbuff_t* tvb_3;
 905                                 union wtap_pseudo_header* pseudo_header_save;
 906                                 union wtap_pseudo_header ph;
 907
 908                                 tvb_3 = tvb_new_subset(tvb_2, 0, payload_size, payload_size);
 909                                 /* prepare pseudo header for atm aal5 decoding */
 910                                 pseudo_header_save = pinfo->pseudo_header;
 911                                 pinfo->pseudo_header = &ph;
 912                                 prepare_pseudo_header_atm(&ph,&pd,AAL_5);
 913                                 call_dissector(dh_atm_truncated, tvb_3, pinfo, tree); /* no PAD and trailer */
 914                                 /* restore pseudo header */
 915                                 pinfo->pseudo_header = pseudo_header_save;
 916                         }
 917                         if (padding_size != 0)
 918                         {
 919                                 tvbuff_t* tvb_3;
 920                                 tvb_3 = tvb_new_subset(tvb_2, payload_size, padding_size, -1);
 921                                 call_dissector(dh_padding, tvb_3, pinfo, tree);
 922                         }
 923                 }
 924         }
 925
 926         pinfo->private_data = pd_save;
 927         return;
 928 }
 929
 930
 931 static
 932 void dissect_n1_cw(tvbuff_t * tvb, packet_info * pinfo, proto_tree * tree)
 933 {
 934         const char *proto_name_column;
 935         gint payload_size;
 936         gint padding_size;
 937         int cells;
 938         pwatm_private_data_t pd = PWATM_PRIVATE_DATA_T_INITIALIZER;
 939         void * pd_save = pinfo->private_data;
 940
 941         pinfo->private_data = &pd;
 942         pd.mode = PWATM_MODE_N1_CW;
 943
 944         proto_name_column = &shortname_n1_cw[0];
 945         if (too_small_packet_or_notpw(tvb,pinfo,tree,proto_n1_cw,proto_name_column))
 946         {
 947                 return;
 948         }
 949         pd.packet_size = tvb_reported_length_remaining(tvb, 0);
 950
 951         /* check how "good" is this packet */
 952         /* also decide payload length from packet size and CW */
 953         pd.props = PWC_PACKET_PROPERTIES_T_INITIALIZER;
 954         if (0 != (tvb_get_guint8(tvb, 0) & 0xf0 /*bits03*/))
 955         {
 956                 pd.props |= PWC_CW_BAD_BITS03;
 957         }
 958         if (0 != (tvb_get_guint8(tvb, 0) & 0x0f /*preferred_cw.flags*/))
 959         {
 960                 pd.props |= PWC_CW_BAD_FLAGS;
 961         }
 962         if (! pref_n1_cw_extend_cw_length_with_rsvd)
 963         {
 964                 if (0 != (tvb_get_guint8(tvb, 1) & 0xc0 /*preferred_cw.rsvd*/))
 965                 {
 966                         pd.props |= PWC_CW_BAD_RSV;
 967                 }
 968         }
 969         {
 970                 /* RFC4717:
 971                  * [ If the packet's length (defined as the length of the layer 2 payload
 972                  * plus the length of the control word) is less than 64 bytes, the
 973                  * length field MUST be set to the packet's length.  Otherwise, the
 974                  * length field MUST be set to zero... Note that the length field
 975                  * is not used in the N-to-one mode and MUST be set to 0. ]
 976                  *
 977                  * Also we allow some "extensions"conducted by pref_xxx.
 978                  */
 979                 gint payload_size_from_packet;
 980                 int cw_len; /*length field from cw*/
 981
 982                 payload_size_from_packet = pd.packet_size - PWC_SIZEOF_CW;
 983                 if (pref_n1_cw_extend_cw_length_with_rsvd)
 984                 {
 985                         cw_len = tvb_get_guint8(tvb, 1) & 0xff;
 986                 }
 987                 else
 988                 {
 989                         cw_len = tvb_get_guint8(tvb, 1) & 0x3f;
 990                 }
 991
 992                 /*
 993                  * Initial assumptions: no padding,
 994                  * payload size derived from psn packet size.
 995                  */
 996                 payload_size = payload_size_from_packet;
 997                 padding_size = 0;
 998
 999                 if (0 == cw_len)
1000                 {
1001                         /*keep initial assumptions*/
1002                 }
1003                 else if (!pref_n1_cw_allow_cw_length_nonzero)
1004                 {
1005                         pd.props |= PWC_CW_BAD_LEN_MUST_BE_0;
1006                 }
1007                 else
1008                 {
1009                         gint payload_size_from_cw;
1010                         payload_size_from_cw = cw_len - PWC_SIZEOF_CW;
1011                         if (payload_size_from_cw <= 0)
1012                         {
1013                                 pd.props |= PWC_CW_BAD_PAYLEN_LE_0;
1014                         }
1015                         else if (payload_size_from_cw > payload_size_from_packet)
1016                         {
1017                                 pd.props |= PWC_CW_BAD_PAYLEN_GT_PACKET;
1018                         }
1019                         else
1020                         {
1021
1022                                 payload_size = payload_size_from_cw;
1023                                 padding_size = payload_size_from_packet - payload_size_from_cw; /* >=0 */
1024                                 if (padding_size != 0)
1025                                 {
1026                                         pd.props |= PWC_CW_BAD_PADDING_NE_0;
1027                                         /*restore sizes*/
1028                                         payload_size = payload_size_from_packet;
1029                                         padding_size = 0;
1030                                 }
1031                         }
1032                 }
1033                 {
1034                         gint bad_padding_size;
1035                         cells = number_of_cells(pd.mode,pd.submode,payload_size,&bad_padding_size);
1036                         if (0 == cells || 0 != bad_padding_size)
1037                         {
1038                                 pd.props |= PWC_PAY_SIZE_BAD;
1039                         }
1040                 }
1041         }
1042
1043         if (tree)
1044         {
1045                 proto_item* item;
1046                 item = proto_tree_add_item(tree, proto_n1_cw, tvb, 0, -1, FALSE);
1047                 pwc_item_append_text_n_items(item,cells,"good ATM cell");
1048                 {
1049                         proto_tree* tree;
1050                         tree = proto_item_add_subtree(item, ett_encaps);
1051                         {
1052                                 proto_item* item;
1053                                 item = proto_tree_add_boolean(tree, hf_pw_type_n1_cw, tvb, 0, 0, TRUE);
1054                                 PROTO_ITEM_SET_GENERATED(item);
1055                                 item = proto_tree_add_int(tree, hf_n1_cw_ncells, tvb, 0, 0, cells);
1056                                 PROTO_ITEM_SET_GENERATED(item);
1057                         }
1058                 }
1059                 if (pd.props & PWC_PAY_SIZE_BAD)
1060                 {
1061                         if (payload_size != 0)
1062                         {
1063                                 expert_add_info_format(pinfo, item, PI_MALFORMED, PI_ERROR,
1064                                         "PW ATM cell [%.3d] is broken",(int)cells);
1065                         }
1066                         expert_add_info_format(pinfo, item, PI_MALFORMED
1067                                 , (payload_size == 0) ? PI_ERROR : PI_NOTE
1068                                 ,"PW payload size (%d) must be <>0 and multiple of %d"
1069                                 ,(int)payload_size,(int)SIZEOF_N1_PW_CELL);
1070                 }
1071         }
1072
1073         {
1074                 tvbuff_t* tvb_2;
1075                 tvb_2 = tvb_new_subset(tvb, 0, PWC_SIZEOF_CW, PWC_SIZEOF_CW);
1076                 call_dissector(dh_control_word, tvb_2, pinfo, tree);
1077
1078                 tvb_2 = tvb_new_subset_remaining(tvb, PWC_SIZEOF_CW);
1079                 dissect_payload_and_padding(tvb_2,pinfo,tree,payload_size,padding_size);
1080         }
1081
1082         /* fill columns in Packet List */
1083         /* overwrite everything written by sub-dissectors */
1084         if (check_col(pinfo->cinfo, COL_PROTOCOL))
1085         {
1086                 col_set_str(pinfo->cinfo, COL_PROTOCOL, proto_name_column);
1087         }
1088
1089         if (check_col(pinfo->cinfo, COL_INFO))
1090         {
1091                 col_clear(pinfo->cinfo, COL_INFO);
1092                 col_append_pw_info(pinfo, payload_size, cells, padding_size);
1093         }
1094
1095         pinfo->private_data = pd_save;
1096         return;
1097 }
1098
1099
1100 static
1101 void dissect_n1_nocw(tvbuff_t * tvb, packet_info * pinfo, proto_tree * tree)
1102 {
1103         const char *proto_name_column = &shortname_n1_nocw[0];
1104         gint payload_size;
1105         int cells;
1106         pwatm_private_data_t pd = PWATM_PRIVATE_DATA_T_INITIALIZER;
1107         void * pd_save = pinfo->private_data;
1108
1109         pinfo->private_data = &pd;
1110         pd.mode = PWATM_MODE_N1_NOCW;
1111         pd.packet_size = tvb_reported_length_remaining(tvb, 0);
1112
1113         /* check how "good" is this packet */
1114         /* also decide payload length from packet size */
1115         pd.props = PWC_PACKET_PROPERTIES_T_INITIALIZER;
1116         payload_size = pd.packet_size;
1117         {
1118                 gint bad_padding_size;
1119                 cells = number_of_cells(pd.mode,pd.submode,pd.packet_size,&bad_padding_size);
1120                 if (cells == 0 || bad_padding_size != 0)
1121                 {
1122                         pd.props |= PWC_PAY_SIZE_BAD;
1123                 }
1124         }
1125
1126         if (tree)
1127         {
1128                 proto_item* item;
1129                 item = proto_tree_add_item(tree, proto_n1_nocw, tvb, 0, -1, FALSE);
1130                 pwc_item_append_text_n_items(item,cells,"ATM cell");
1131                 {
1132                         proto_tree* tree;
1133                         tree = proto_item_add_subtree(item, ett_encaps);
1134                         {
1135                                 proto_item* item;
1136                                 item = proto_tree_add_boolean(tree, hf_pw_type_n1_nocw, tvb, 0, 0, TRUE);
1137                                 PROTO_ITEM_SET_GENERATED(item);
1138                                 item = proto_tree_add_int(tree, hf_n1_nocw_ncells, tvb, 0, 0, cells);
1139                                 PROTO_ITEM_SET_GENERATED(item);
1140                         }
1141                 }
1142                 if (pd.props & PWC_PAY_SIZE_BAD)
1143                 {
1144                         if (payload_size != 0)
1145                         {
1146                                 expert_add_info_format(pinfo, item, PI_MALFORMED, PI_ERROR,
1147                                         "Last PW ATM cell [%.3d] is broken",(int)cells);
1148                         }
1149                         expert_add_info_format(pinfo, item, PI_MALFORMED
1150                                 , (payload_size == 0) ? PI_ERROR : PI_NOTE
1151                                 ,"PW payload size (%d) must be <>0 and multiple of %d"
1152                                 ,(int)payload_size,(int)SIZEOF_N1_PW_CELL);
1153                 }
1154         }
1155
1156         dissect_payload_and_padding(tvb,pinfo,tree,payload_size,0);
1157
1158         /* fill columns in Packet List */
1159         /* overwrite everything written by sub-dissectors */
1160         if (check_col(pinfo->cinfo, COL_PROTOCOL))
1161         {
1162                 col_set_str(pinfo->cinfo, COL_PROTOCOL, proto_name_column);
1163         }
1164
1165         if (check_col(pinfo->cinfo, COL_INFO))
1166         {
1167                 col_clear(pinfo->cinfo, COL_INFO);
1168                 col_append_pw_info(pinfo, payload_size, cells, 0);
1169         }
1170
1171         pinfo->private_data = pd_save;
1172         return;
1173 }
1174
1175
1176 static
1177 void proto_item_append_text_cwb3_fields(proto_item * item, const pwatm_private_data_t * const pd)
1178 {
1179         if (NULL == item) return;
1180         DISSECTOR_ASSERT(NULL != pd);
1181         if (pd->cwb3.m   >= 0)
1182                 proto_item_append_text(item, "M:%.1u  "  , (unsigned)(pd->cwb3.m));
1183         if (pd->cwb3.v   >= 0)
1184                 proto_item_append_text(item, "V:%.1u  "  , (unsigned)(pd->cwb3.v));
1185         if (pd->cwb3.rsv >= 0)
1186                 proto_item_append_text(item, "RSV:%.1u  ", (unsigned)(pd->cwb3.rsv));
1187         if (pd->cwb3.u >= 0)
1188                 proto_item_append_text(item, "U:%.1u  "  , (unsigned)(pd->cwb3.u));
1189         if (pd->cwb3.e >= 0)
1190                 proto_item_append_text(item, "EFCI:%.1u  ",(unsigned)(pd->cwb3.e));
1191         if (pd->cwb3.clp >= 0)
1192                 proto_item_append_text(item, "CLP:%.1u  ", (unsigned)(pd->cwb3.clp));
1193         return;
1194 }
1195
1196
1197 static
1198 void dissect_control_word(tvbuff_t * tvb, packet_info * pinfo, proto_tree * tree)
1199 {
1200         pwatm_private_data_t* pd;
1201         pd = pinfo->private_data;
1202         DISSECTOR_ASSERT(pd != NULL);
1203
1204         /*
1205          * NB: do not touch columns -- keep info from previous dissector
1206          */
1207
1208         {
1209                 gint size;
1210                 size = tvb_reported_length_remaining(tvb, 0);
1211                 if (size < PWC_SIZEOF_CW)
1212                 {
1213                         if (tree)
1214                         {
1215                                 proto_item  *item;
1216                                 item = proto_tree_add_item(tree, proto_control_word, tvb, 0, -1, FALSE);
1217                                 expert_add_info_format(pinfo, item, PI_MALFORMED, PI_ERROR,
1218                                         "Packet (size: %d) is too small to carry MPLS PW Control Word"
1219                                         ,(int)size);
1220                         }
1221                         return;
1222                 }
1223         }
1224
1225         if (tree)
1226         {
1227                 proto_item* item_top;
1228                 item_top = proto_tree_add_item(tree, proto_control_word, tvb, 0, -1, FALSE);
1229                 pwc_item_append_cw(item_top,tvb_get_ntohl(tvb, 0),FALSE);
1230
1231                 {
1232                         proto_tree* tree;
1233                         tree = proto_item_add_subtree(item_top, ett_cw);
1234                         {
1235                                 proto_item* item;
1236                                 /* bits 0..3 */
1237                                 item = proto_tree_add_item(tree, hf_cw_bits03, tvb, 0, 1, FALSE);
1238                                 if (pd->props & PWC_CW_BAD_BITS03)
1239                                 {
1240                                         /* add item to tree (and show it) only if its value is wrong*/
1241                                         expert_add_info_format(pinfo, item, PI_MALFORMED, PI_ERROR
1242                                                 ,"Bits 0..3 of Control Word must be 0");
1243                                 }
1244                                 else
1245                                 {
1246                                         PROTO_ITEM_SET_HIDDEN(item); /* show only in error cases */
1247                                 }
1248
1249                                 /* flags */
1250                                 if (MODE_N1(pd->mode))
1251                                 {
1252                                         item = proto_tree_add_item(tree, hf_pref_cw_flags, tvb, 0, 1, FALSE);
1253                                         if (pd->props & PWC_CW_BAD_FLAGS)
1254                                         {
1255                                                 expert_add_info_format(pinfo, item, PI_MALFORMED, PI_ERROR
1256                                                         ,"Flags must be 0 for PW ATM N:1 encapsulation");
1257                                         }
1258                                 }
1259                                 if (pd->mode == PWATM_MODE_AAL5_SDU)
1260                                 {
1261                                         item = proto_tree_add_item(tree, hf_pref_cw_a5s_t, tvb, 0, 1, FALSE);
1262                                         item = proto_tree_add_item(tree, hf_pref_cw_a5s_e, tvb, 0, 1, FALSE);
1263                                         item = proto_tree_add_item(tree, hf_pref_cw_a5s_c, tvb, 0, 1, FALSE);
1264                                         item = proto_tree_add_item(tree, hf_pref_cw_a5s_u, tvb, 0, 1, FALSE);
1265                                         /*
1266                                          * rfc4717: [When FRF.8.1 Frame Relay/ATM PVC Service Interworking [RFC3916]
1267                                          * traffic is being transported, the CPCS-UU Least Significant Bit
1268                                          * (LSB) of the AAL5 CPCS-PDU may contain the Frame Relay C/R bit.
1269                                          * The ingress router, PE1, SHOULD copy this bit to the U bit of the
1270                                          * control word.  The egress router, PE2, SHOULD copy the U bit to
1271                                          * the CPCS-UU Least Significant Bit (LSB) of the AAL5 CPCS PDU.]
1272                                          *
1273                                          * Let's remember this bit (and then transfer it to ATM dissector).
1274                                          */
1275                                         pd->aal5_sdu_frame_relay_cr_bit =
1276                                                 (0 == (tvb_get_guint8(tvb, 0) & 0x01 /*preferred_cw.U*/))
1277                                                 ? FALSE : TRUE;
1278                                 }
1279
1280                                 /* reserved bits */
1281                                 if (MODE_11_OR_AAL5_PDU(pd->mode)
1282                                 || (MODE_N1(pd->mode) && !pref_n1_cw_extend_cw_length_with_rsvd)
1283                                         /* for N:1 add RSV only if it is NOT used in length */
1284                                 || ((pd->mode == PWATM_MODE_AAL5_SDU) && !pref_aal5_sdu_extend_cw_length_with_rsvd)
1285                                         /* for AAl5 SDU add RSV only if it is NOT used in length */)
1286                                 {
1287                                         if (MODE_11_OR_AAL5_PDU(pd->mode))
1288                                         {
1289                                                 item = proto_tree_add_item(tree
1290                                                         ,hf_generic_cw_rsv, tvb, 0, 1, FALSE);
1291                                         }
1292                                         else
1293                                         { /*preferred cw*/
1294                                                 item = proto_tree_add_item(tree
1295                                                         ,hf_pref_cw_rsv, tvb, 1, 1, FALSE);
1296                                         }
1297
1298                                         if (pd->props & PWC_CW_BAD_RSV)
1299                                         {
1300                                                 expert_add_info_format(pinfo, item, PI_MALFORMED, PI_ERROR
1301                                                         ,"Reserved bits in Control Word must be 0");
1302                                         }
1303                                         else
1304                                         {
1305                                                 PROTO_ITEM_SET_HIDDEN(item); /*...and show only in error cases */
1306                                         }
1307                                 }
1308
1309                                 /* length */
1310                                 if (MODE_N1(pd->mode)
1311                                 || (PWATM_MODE_AAL5_SDU == pd->mode))
1312                                 {
1313                                         {
1314                                                 int hf_len = hf_pref_cw_len;
1315                                                 if (MODE_N1(pd->mode))
1316                                                 {
1317                                                         if (pref_n1_cw_extend_cw_length_with_rsvd)
1318                                                                 hf_len = hf_pref_cw_rsvlen;
1319                                                 }
1320                                                 else /*PW_MODE_AAL5_SDU*/
1321                                                 {
1322                                                         if (pref_aal5_sdu_extend_cw_length_with_rsvd)
1323                                                                 hf_len = hf_pref_cw_rsvlen;
1324                                                 }
1325                                                 item = proto_tree_add_item(tree, hf_len, tvb, 1, 1, FALSE);
1326                                         }
1327                                         if (pd->props & PWC_CW_BAD_LEN_MUST_BE_0)
1328                                         {
1329                                                 expert_add_info_format(pinfo, item, PI_MALFORMED, PI_ERROR
1330                                                         ,"Bad Length: must be 0 for this encapsulation");
1331                                         }
1332                                         if (pd->props & PWC_CW_BAD_PAYLEN_LE_0)
1333                                         {
1334                                                 expert_add_info_format(pinfo, item, PI_MALFORMED, PI_ERROR
1335                                                         ,"Bad Length: too small, must be >= %d"
1336                                                         ,(int)(PWC_SIZEOF_CW+SIZEOF_N1_PW_CELL));
1337                                         }
1338                                         if (pd->props & PWC_CW_BAD_PAYLEN_GT_PACKET)
1339                                         {
1340                                                 expert_add_info_format(pinfo, item, PI_MALFORMED, PI_ERROR
1341                                                         ,"Bad Length: must be <= than PSN packet size (%d)"
1342                                                         ,(int)pd->packet_size);
1343                                         }
1344                                         if (pd->props & PWC_CW_BAD_PADDING_NE_0)
1345                                         {
1346                                                 expert_add_info_format(pinfo, item, PI_MALFORMED, PI_ERROR
1347                                                         ,"Bad Length: must be == PSN packet size (%d), no padding allowed"
1348                                                         ,(int)pd->packet_size);
1349                                         }
1350                                 }
1351
1352                                 /* sequence number */
1353                                 (void)proto_tree_add_item(tree, hf_cw_seq, tvb
1354                                         ,MODE_11_OR_AAL5_PDU(pd->mode) ? 1 : 2, 2, FALSE);
1355
1356                                 /* atm-specific byte */
1357                                 if (MODE_11(pd->mode))
1358                                 {
1359                                         (void) proto_tree_add_item(tree, hf_gen_cw_atmbyte, tvb, 3, 1, FALSE);
1360                                         /*
1361                                          * no need to highlight item in the tree, therefore
1362                                          * expert_add_info_format() is not used here.
1363                                          */
1364                                         item = proto_tree_add_text(tree,tvb,3,1
1365                                                 ,"ATM-specific byte of CW is fully dissected below as %s%s"
1366                                                 ,(PWATM_MODE_11_VPC == pd->mode) ? "a part of " : ""
1367                                                 ,"PW ATM Cell Header [000]");
1368                                         PROTO_ITEM_SET_GENERATED(item);
1369                                         /*
1370                                          * Note: if atm-specific byte contains something wrong
1371                                          * (e.g. non-zero RSV or inadequate V), CW is not
1372                                          * marked as "bad".
1373                                          */
1374                                 }
1375
1376                                 /*3rd byte of CW*/
1377                                 if (PWATM_MODE_AAL5_PDU == pd->mode)
1378                                 {
1379                                         tvbuff_t* tvb_2;
1380                                         tvb_2 = tvb_new_subset(tvb, (PWC_SIZEOF_CW-1), -1, -1);
1381                                         call_dissector(dh_cell_header, tvb_2, pinfo, tree);
1382                                         proto_item_append_text(item_top,", ");
1383                                         proto_item_append_text_cwb3_fields(item_top,pd);
1384                                 }
1385                         }
1386                 }
1387         }
1388         return;
1389 }
1390
1391
1392 /*
1393  * This function is also used to dissect 3rd byte of CW in AAL5 PDU mode.
1394  */
1395 static
1396 int dissect_cell_header(tvbuff_t * tvb, packet_info * pinfo, proto_tree * tree)
1397 {
1398         pwatm_private_data_t * pd;
1399         gboolean is_enough_data;
1400         int dissect_size;
1401
1402         pd = pinfo->private_data;
1403         DISSECTOR_ASSERT (NULL != pd);
1404         pd->vpi = pd->vci = pd->pti = -1;
1405         pd->cwb3.clp = pd->cwb3.m = pd->cwb3.v = pd->cwb3.rsv = pd->cwb3.u = pd->cwb3.e = -1;
1406
1407         if (PWATM_MODE_AAL5_PDU == pd->mode)
1408         {
1409                 if (tvb_reported_length_remaining(tvb, 0) < 1)
1410                 {
1411                         is_enough_data = FALSE;
1412                         dissect_size = 0;
1413                 }
1414                 else
1415                 {
1416                         is_enough_data = TRUE;
1417                         dissect_size = 1;
1418                 }
1419         }
1420         else
1421         {
1422                 gint size;
1423                 size = tvb_reported_length_remaining(tvb, 0);
1424
1425                 if (size < pw_cell_header_size(pd->mode,pd->submode))
1426                 {
1427                         is_enough_data = FALSE;
1428                         dissect_size = size;
1429                 }
1430                 else
1431                 {
1432                         is_enough_data = TRUE;
1433                         dissect_size = pw_cell_header_size(pd->mode,pd->submode);
1434                 }
1435         }
1436
1437         /*
1438          * NB: do not touch columns -- keep info from previous dissector
1439          */
1440
1441         /* Collect info for upper-level dissectors regardless of
1442          * the presence of the tree
1443          */
1444         if (is_enough_data)
1445         {
1446                 guint8 tmp8;
1447                 switch (pd->mode)
1448                 {
1449                 case PWATM_MODE_AAL5_SDU:
1450                         DISSECTOR_ASSERT(pd->submode == PWATM_SUBMODE_ADMIN_CELL);
1451                         /*fallthrough for ATM admin cell submode only*/
1452                 case PWATM_MODE_N1_CW:
1453                 case PWATM_MODE_N1_NOCW:
1454                         pd->vpi         = (tvb_get_ntohs (tvb, 0) >> 4);
1455                         pd->vci         = (tvb_get_ntoh24(tvb, 1) >> 4) & 0xffff;
1456                         tmp8            = (tvb_get_guint8(tvb, 3));
1457                         pd->pti         = (tmp8 >> 1) & 0x07;
1458                         pd->cwb3.clp    = (tmp8 >> 0) & 0x01;
1459                         UPDATE_CUMULATIVE_VALUE(pd->cumulative.vpi,pd->vpi);
1460                         UPDATE_CUMULATIVE_VALUE(pd->cumulative.vci,pd->vci);
1461                         UPDATE_CUMULATIVE_VALUE(pd->cumulative.pti,pd->pti);
1462                         UPDATE_CUMULATIVE_VALUE(pd->cumulative.clp,pd->cwb3.clp);
1463                         /*
1464                          * OAM cell mode is always used for aal5_sdu/admin_cell mode,
1465                          * even if pti indicates user cell.
1466                          */
1467                         pd->cell_mode_oam =
1468                                 (pd->mode == PWATM_MODE_AAL5_SDU && pd->submode == PWATM_SUBMODE_ADMIN_CELL)
1469                                 || PTI_IS_ADMIN(pd->pti);
1470                         break;
1471                 case PWATM_MODE_11_VPC:
1472                         pd->vci = tvb_get_ntohs(tvb, 1);
1473                         UPDATE_CUMULATIVE_VALUE(pd->cumulative.vci,pd->vci);
1474                         /*fallthrough*/
1475                 case PWATM_MODE_11_VCC:
1476                         tmp8    = (tvb_get_guint8(tvb, 0));
1477                         pd->cwb3.m      = (tmp8 >> 7) & 0x1;
1478                         pd->cwb3.v      = (tmp8 >> 6) & 0x1;
1479                         pd->cwb3.rsv    = (tmp8 >> 4) & 0x3;
1480                         pd->pti         = (tmp8 >> 1) & 0x7;
1481                         pd->cwb3.clp    = (tmp8 >> 0) & 0x1;
1482                         UPDATE_CUMULATIVE_VALUE(pd->cumulative.pti,pd->pti);
1483                         UPDATE_CUMULATIVE_VALUE(pd->cumulative.clp,pd->cwb3.clp);
1484                         /*
1485                          * OAM cell mode is possible if packet contains atm cell (m == 0).
1486                          */
1487                         pd->cell_mode_oam = PTI_IS_ADMIN(pd->pti) && (pd->cwb3.m == 0);
1488                         break;
1489                 case PWATM_MODE_AAL5_PDU:
1490                         tmp8            = (tvb_get_guint8(tvb, 0));
1491                         pd->cwb3.m      = (tmp8 >> 7) & 0x1;
1492                         pd->cwb3.v      = (tmp8 >> 6) & 0x1;
1493                         pd->cwb3.rsv    = (tmp8 >> 3) & 0x7;
1494                         pd->cwb3.u      = (tmp8 >> 2) & 0x1;
1495                         pd->cwb3.e      = (tmp8 >> 1) & 0x1;
1496                         pd->cwb3.clp    = (tmp8 >> 0) & 0x1;
1497                         UPDATE_CUMULATIVE_VALUE(pd->cumulative.clp,pd->cwb3.clp);
1498                         break;
1499                 default:
1500                         DISSECTOR_ASSERT_NOT_REACHED();
1501                         break;
1502                 }
1503         }
1504
1505         if (tree)
1506         {
1507                 proto_item* item;
1508
1509                 item = proto_tree_add_item(tree, proto_cell_header, tvb
1510                         ,0
1511                         ,dissect_size
1512                         ,FALSE);
1513                 if (PWATM_MODE_AAL5_PDU == pd->mode)
1514                 {
1515                         proto_item_set_text(item, "Third byte of Control Word"); /*overwrite heading line*/
1516                         /* cwb3 fileds are appended to CW heading line, not here */
1517                 }
1518                 else
1519                 {
1520                         proto_item_append_text(item," [%.3d]",pd->pw_cell_number);
1521                         proto_item_append_text(item,", ");
1522                         if (pd->vpi >= 0)
1523                                 proto_item_append_text(item, "VPI:%.4u  ", (unsigned)(pd->vpi));
1524                         if (pd->vci >= 0)
1525                                 proto_item_append_text(item, "VCI:%.5u  ", (unsigned)(pd->vci));
1526                         if (pd->pti >= 0)
1527                                 proto_item_append_text(item, "PTI:%.1u  ", (unsigned)(pd->pti));
1528                         proto_item_append_text_cwb3_fields(item,pd);
1529                 }
1530
1531                 {
1532                         proto_tree* tree;
1533                         tree = proto_item_add_subtree(item, ett_cell_header);
1534                         if (is_enough_data)
1535                         {
1536                                 proto_item* item;
1537                                 if (MODE_N1(pd->mode)
1538                                     || (pd->mode == PWATM_MODE_AAL5_SDU && pd->submode == PWATM_SUBMODE_ADMIN_CELL))
1539                                 {
1540                                         (void) proto_tree_add_uint(tree, hf_cell_h_vpi, tvb, 0, 2, (unsigned)pd->vpi);
1541                                         (void) proto_tree_add_uint(tree, hf_cell_h_vci, tvb, 1, 3, (unsigned)pd->vci);
1542
1543                                         item = proto_tree_add_item(tree, hf_cell_h_pti, tvb, 3, 1, FALSE);
1544                                         if (NULL == match_strval(pd->pti,atm_pt_vals))
1545                                         {
1546                                                 expert_add_info_format(pinfo, item, PI_UNDECODED, PI_WARN,
1547                                                         "Unknown value of PTI field (%d) in the ATM cell header",
1548                                                         pd->pti);
1549                                         }
1550                                         else if (pd->mode == PWATM_MODE_AAL5_SDU && !PTI_IS_ADMIN(pd->pti))
1551                                         {
1552                                                 expert_add_info_format(pinfo, item, PI_MALFORMED, PI_ERROR,
1553                                                         "ATM admin cell is transerred;"
1554                                                         " PTI field (%d) should be 4, 5 or 6.",
1555                                                         pd->pti);
1556                                         }
1557
1558                                         (void) proto_tree_add_item(tree, hf_cell_h_clp, tvb, 3, 1, FALSE);
1559                                 }
1560                                 else if (MODE_11_OR_AAL5_PDU(pd->mode))
1561                                 {
1562                                         item = proto_tree_add_item(tree, hf_cell_h_m  , tvb, 0, 1, FALSE);
1563                                         if ((0 != pd->cwb3.m) && MODE_11(pd->mode))
1564                                         {
1565                                                 expert_add_info_format(pinfo, item, PI_MALFORMED, PI_ERROR
1566                                                         ,"1:1 mode:"
1567                                                         " M bit must be 0 to distinguish from AAL5 PDU mode");
1568                                         }
1569
1570                                         item = proto_tree_add_item(tree, hf_cell_h_v  , tvb, 0, 1, FALSE);
1571                                         if ((0 == pd->cwb3.v) && (PWATM_MODE_11_VPC == pd->mode))
1572                                         {
1573                                                 expert_add_info_format(pinfo, item, PI_MALFORMED, PI_ERROR
1574                                                         ,"1:1 VPC mode:"
1575                                                         " V bit must be 1 to indicate that VCI is present");
1576                                         }
1577                                         if ((0 != pd->cwb3.v) && (PWATM_MODE_11_VCC == pd->mode))
1578                                         {
1579                                                 expert_add_info_format(pinfo, item, PI_MALFORMED, PI_ERROR
1580                                                         ,"1:1 VCC mode:"
1581                                                         " V bit must be 0 to indicate that VCI is absent");
1582                                         }
1583                                         if ((0 != pd->cwb3.v) && (PWATM_MODE_AAL5_PDU == pd->mode))
1584                                         {
1585                                                 expert_add_info_format(pinfo, item, PI_MALFORMED, PI_ERROR
1586                                                         ,"AAL5 PDU mode:"
1587                                                         " V bit must be 0 to indicate that VCI is absent");
1588                                         }
1589
1590                                         item = proto_tree_add_item(tree
1591                                                 ,(PWATM_MODE_AAL5_PDU == pd->mode)
1592                                                         ? hf_aal5_pdu_rsv
1593                                                         : hf_cell_h_rsv
1594                                                 ,tvb, 0, 1, FALSE);
1595                                         if (0 != pd->cwb3.rsv)
1596                                         {
1597                                                 expert_add_info_format(pinfo, item, PI_MALFORMED, PI_ERROR
1598                                                         ,"Reserved bits in the 3rd byte of CW must be 0");
1599                                         }
1600                                         else
1601                                         {
1602                                                 PROTO_ITEM_SET_HIDDEN(item); /*...and show only in error cases */
1603                                         }
1604
1605                                         if (MODE_11(pd->mode))
1606                                         {
1607                                                 item = proto_tree_add_item(tree, hf_cell_h_pti, tvb, 0, 1, FALSE);
1608                                                 if (NULL == match_strval(pd->pti,atm_pt_vals))
1609                                                 {
1610                                                         expert_add_info_format(pinfo, item, PI_UNDECODED, PI_WARN,
1611                                                                 "Unknown value of PTI field (%d) in the atm-specific byte"
1612                                                                 ,pd->pti);
1613                                                 }
1614                                         }
1615                                         else
1616                                         {
1617                                                 (void) proto_tree_add_item(tree, hf_aal5_pdu_u, tvb, 0, 1, FALSE);
1618                                                 (void) proto_tree_add_item(tree, hf_aal5_pdu_e, tvb, 0, 1, FALSE);
1619                                         }
1620
1621                                         (void) proto_tree_add_item(tree, hf_cell_h_clp, tvb, 0, 1, FALSE);
1622
1623                                         if (PWATM_MODE_11_VPC == pd->mode)
1624                                         {
1625                                                 (void) proto_tree_add_uint(tree, hf_cell_h_vci, tvb, 1, 2
1626                                                         ,(unsigned)pd->vci);
1627                                         }
1628                                 }
1629                                 else
1630                                 {
1631                                         DISSECTOR_ASSERT_NOT_REACHED();
1632                                 }
1633                         }
1634                         else
1635                         {
1636                                 expert_add_info_format(pinfo, item, PI_MALFORMED, PI_ERROR
1637                                         ,"Not enough data (size: %d), impossible to decode"
1638                                         ,(int)dissect_size);
1639                         }
1640                 }
1641         }
1642         return dissect_size;
1643 }
1644
1645
1646 static
1647 int dissect_cell(tvbuff_t * tvb, packet_info * pinfo, proto_tree * tree)
1648 {
1649         gboolean is_enough_data;
1650         int dissect_size;
1651
1652         {
1653                 gint size;
1654                 size = tvb_reported_length_remaining(tvb, 0);
1655                 if (size < SIZEOF_ATM_CELL_PAYLOAD)
1656                 {
1657                         is_enough_data = FALSE;
1658                         dissect_size = size;
1659                 }
1660                 else
1661                 {
1662                         is_enough_data = TRUE;
1663                         dissect_size = SIZEOF_ATM_CELL_PAYLOAD;
1664                 }
1665         }
1666
1667         /*
1668          * NB: do not touch columns -- keep info from previous dissector
1669          */
1670
1671         if (tree)
1672         {
1673                 proto_item* item;
1674                 item = proto_tree_add_item(tree, proto_cell, tvb, 0, dissect_size, FALSE);
1675                 {
1676                         pwatm_private_data_t * pd;
1677                         pd = pinfo->private_data;
1678                         if (NULL != pd)
1679                         {
1680                                 proto_item_append_text(item," [%.3d]",pd->pw_cell_number);
1681                         }
1682                 }
1683                 pwc_item_append_text_n_items(item,dissect_size,"byte");
1684                 if (!is_enough_data)
1685                 {
1686                         expert_add_info_format(pinfo, item, PI_MALFORMED, PI_ERROR
1687                                 ,"Bad length of cell payload: must be == %d"
1688                                 ,(int)SIZEOF_ATM_CELL_PAYLOAD);
1689                 }
1690
1691                 {
1692                         proto_tree* tree;
1693                         tvbuff_t* tvb_d;
1694                         tree = proto_item_add_subtree(item, ett_cell);
1695                         tvb_d = tvb_new_subset(tvb, 0, dissect_size, -1);
1696                         call_dissector(dh_data, tvb_d, pinfo, tree);
1697                         item = proto_tree_add_int(tree, hf_cell_payload_len, tvb, 0, 0, dissect_size);
1698                         PROTO_ITEM_SET_HIDDEN(item);
1699                 }
1700         }
1701         return dissect_size;
1702 }
1703
1704
1705 void proto_register_pw_atm_ata(void)
1706 {
1707         static const value_string clp_vals[] = {
1708                 { 0, "High priority" },
1709                 { 1, "Low priority" },
1710                 { 0, NULL }
1711         };
1712         static const value_string m_vals[] = {
1713                 { 0, "ATM cell" },
1714                 { 1, "AAL5 payload" },
1715                 { 0, NULL }
1716         };
1717         static const value_string u_vals[] = {
1718                 { 0, "This frame does not contain the last cell of AAL5 PDU" },
1719                 { 1, "This frame contains the last cell of AAL5 PDU" },
1720                 { 0, NULL }
1721         };
1722         static const value_string e_vals[] = {
1723                 { 0, "Congestion is not experienced" },
1724                 { 1, "Congestion is experienced for one or more ATM AAL5 cells" },
1725                 { 0, NULL }
1726         };
1727         static hf_register_info hfa_cell_header[] = {
1728                 { &hf_cell_h_vpi        ,{"VPI"                         ,"atm.vpi"
1729                                         ,FT_UINT16      ,BASE_DEC       ,NULL           ,0
1730                                         ,NULL                                           ,HFILL }}
1731                 ,{ &hf_cell_h_vci       ,{"VCI"                         ,"atm.vci"
1732                                         ,FT_UINT16      ,BASE_DEC       ,NULL           ,0
1733                                         ,NULL                                           ,HFILL }}
1734                 ,{ &hf_cell_h_pti       ,{"Payload Type"                ,"atm.pti"
1735                                         ,FT_UINT8       ,BASE_DEC       ,VALS(atm_pt_vals),0x0e
1736                                         ,"The 3-bit Payload Type Identifier (PTI) incorporates ATM Layer"
1737                                         " PTI coding of the cell.  These bits are set to the value of the"
1738                                         " PTI of the encapsulated ATM cell."
1739                                                                                         ,HFILL }}
1740                 ,{ &hf_cell_h_clp       ,{"Cell Loss Priority"          ,"atm.clp"
1741                                         ,FT_UINT8       ,BASE_DEC       ,VALS(clp_vals) ,0x01
1742                                         ,"The Cell Loss Priority (CLP) field indicates CLP value"
1743                                         " of the encapsulated cell."
1744                                                                                         ,HFILL }}
1745                 ,{ &hf_cell_h_m         ,{"Transport Mode"              ,"atm.pw_control_byte.m"
1746                                         ,FT_UINT8       ,BASE_DEC       ,VALS(m_vals)   ,0x80
1747                                         ,"Bit (M) of the control byte indicates  whether the packet"
1748                                         " contains an ATM cell or a frame payload. If set to 0,"
1749                                         " the packet contains an ATM cell. If set to 1, the PDU"
1750                                         " contains an AAL5 payload."
1751                                                                                         ,HFILL }}
1752                 ,{ &hf_cell_h_v         ,{"VCI Present"                 ,"atm.pw_control_byte.v"
1753                                         ,FT_BOOLEAN     ,8              ,TFS(&tfs_yes_no),0x40
1754                                         ,"Bit (V) of the control byte indicates whether the VCI field"
1755                                         " is present in the packet. If set to 1, the VCI field is present"
1756                                         " for the cell. If set to 0, no VCI field is present."
1757                                                                                         ,HFILL }}
1758                 ,{ &hf_cell_h_rsv       ,{"Reserved bits"               ,"atm.pw_control_byte.rsv"
1759                                         ,FT_UINT8       ,BASE_DEC       ,NULL           ,0x30
1760                                         ,"The reserved bits should be set to 0 at the transmitter and"
1761                                         " ignored upon reception."
1762                                                                                         ,HFILL }}
1763                 ,{ &hf_aal5_pdu_rsv     ,{"Reserved bits"               ,"atm.pw_control_byte.rsv"
1764                                         ,FT_UINT8       ,BASE_DEC       ,NULL           ,0x38
1765                                         ,"The reserved bits should be set to 0 at the transmitter and"
1766                                         " ignored upon reception."
1767                                                                                         ,HFILL }}
1768                 ,{ &hf_aal5_pdu_u       ,{"U bit"                       ,"atm.pw_control_byte.u"
1769                                         ,FT_UINT8       ,BASE_DEC       ,VALS(u_vals)   ,0x04
1770                                         ,"Indicates whether this frame contains the last cell of"
1771                                         " an AAL5 PDU and represents the value of the ATM User-to-User"
1772                                         " bit for the last ATM cell of the PSN frame. Note: The ATM"
1773                                         " User-to-User bit is the least significant bit of the PTI"
1774                                         " in the ATM header."
1775                                                                                         ,HFILL }}
1776                 ,{ &hf_aal5_pdu_e       ,{"EFCI"                        ,"atm.pw_control_byte.efci"
1777                                         ,FT_UINT8       ,BASE_DEC       ,VALS(e_vals)   ,0x02
1778                                         ,"EFCI is set to the EFCI state of the last cell of the"
1779                                         " AAL5 PDU or AAL5 fragment. Note: The EFCI state is"
1780                                         " indicated in the middle bit of each ATM cell's PTI."
1781                                                                                         ,HFILL }}
1782         };
1783 static hf_register_info hfa_cell[] = {
1784         {&hf_cell_payload_len   ,{"Length"                      ,"atm.cell.len"
1785                                         ,FT_INT32       ,BASE_DEC       ,NULL           ,0
1786                                         ,NULL                                           ,HFILL }}
1787         };
1788
1789         #define HF_INITIALIZER_NCELLS(hf_handle)\
1790                 {&(hf_handle)           ,{"Number of good encapsulated cells","pw.atm.cells"\
1791                                         ,FT_INT32       ,BASE_DEC       ,NULL           ,0\
1792                                         ,NULL                                           ,HFILL }}
1793
1794         #define HF_INITIALIZER_PWTYPE(hf_handle,name)\
1795                 { &hf_handle            ,{name                          ,name\
1796                                         ,FT_BOOLEAN     ,0              ,NULL           ,0x0\
1797                                         ,"Identifies type of ATM PW. May be used for filtering.",HFILL}}
1798
1799
1800         static hf_register_info hfa_n1_nocw[] = {
1801                  HF_INITIALIZER_NCELLS(hf_n1_nocw_ncells)
1802                 ,HF_INITIALIZER_PWTYPE(hf_pw_type_n1_nocw,"pw.type.atm.n1nocw")
1803         };
1804
1805         static hf_register_info hfa_n1_cw[] = {
1806                  HF_INITIALIZER_NCELLS(hf_n1_cw_ncells)
1807                 ,HF_INITIALIZER_PWTYPE(hf_pw_type_n1_cw,"pw.type.atm.n1cw")
1808         };
1809
1810         static hf_register_info hfa_11_aal5pdu[] = {
1811                  HF_INITIALIZER_NCELLS(hf_11_ncells)
1812                 ,HF_INITIALIZER_PWTYPE(hf_pw_type_11_vcc,"pw.type.atm.11vcc")
1813                 ,HF_INITIALIZER_PWTYPE(hf_pw_type_11_vpc,"pw.type.atm.11vpc")
1814                 ,HF_INITIALIZER_PWTYPE(hf_pw_type_aal5_pdu,"pw.type.atm.aal5pdu")
1815         };
1816
1817         static hf_register_info hfa_aal5_sdu[] = {
1818                 HF_INITIALIZER_PWTYPE(hf_pw_type_aal5_sdu,"pw.type.atm.aal5sdu")
1819         };
1820
1821         static const value_string a5s_t_vals[] = {
1822                 { 0, "AAL5 payload" },
1823                 { 1, "ATM admin cell" },
1824                 { 0, NULL }
1825         };
1826
1827         static const value_string a5s_e_vals[] = {
1828                 { 0, "No congestion" },
1829                 { 1, "Congestion experienced" },
1830                 { 0, NULL }
1831         };
1832
1833         static hf_register_info hfa_cw[] = {
1834                 { &hf_cw_bits03         ,{"Bits 0 to 3"                 ,"pw.cw.bits03"
1835                                         ,FT_UINT8       ,BASE_HEX       ,NULL           ,0xf0
1836                                         ,NULL                                           ,HFILL }}
1837                 ,{ &hf_pref_cw_flags    ,{"Flags"                       ,"pw.cw.flags"
1838                                         ,FT_UINT8       ,BASE_HEX       ,NULL           ,0x0f
1839                                         ,NULL                                           ,HFILL }}
1840                 ,{ &hf_pref_cw_a5s_t    ,{"Payload type"                ,"atm.pt"
1841                                         ,FT_UINT8       ,BASE_DEC       ,VALS(a5s_t_vals),0x08
1842                                         ,"Bit (T) of the control word indicates whether the packet contains"
1843                                         " an ATM admin cell or an AAL5 payload. If T = 1, the packet"
1844                                         " contains an ATM admin cell, encapsulated according to the N:1"
1845                                         " cell relay encapsulation. If not set, the PDU"
1846                                         " contains an AAL5 payload."
1847                                                                                         ,HFILL }}
1848                 ,{ &hf_pref_cw_a5s_e    ,{"EFCI bit"                    ,"atm.efci"
1849                                         ,FT_UINT8       ,BASE_DEC       ,VALS(a5s_e_vals),0x04
1850                                         ,"The ingress router sets this bit to 1 if the EFCI bit"
1851                                         " of the final cell of those that transported the AAL5 CPCS-SDU is"
1852                                         " set to 1, or if the EFCI bit of the single ATM cell to be"
1853                                         " transported in the packet is set to 1. Otherwise, this bit"
1854                                         " is set to 0."
1855                                                                                         ,HFILL }}
1856                 ,{ &hf_pref_cw_a5s_c    ,{"CLP bit"                     ,"atm.clp"
1857                                         ,FT_UINT8       ,BASE_DEC       ,VALS(clp_vals) ,0x02
1858                                         ,"The ingress router sets this bit to 1 if the CLP bit"
1859                                         " of any of the ATM cells that transported the AAL5 CPCS-SDU is set"
1860                                         " to 1, or if the CLP bit of the single ATM cell to be transported"
1861                                         " in the packet is set to 1. Otherwise this bit is set to 0."
1862                                                                                         ,HFILL }}
1863                 ,{ &hf_pref_cw_a5s_u    ,{"U bit (Command/Response)"    ,"pw.cw.aal5sdu.u"
1864                                         ,FT_UINT8       ,BASE_DEC       ,NULL           ,0x01
1865                                         ,"When FRF.8.1 Frame Relay/ATM PVC Service Interworking [RFC3916]"
1866                                         " traffic is being transported, the Least-Significant Bit of CPCS-UU"
1867                                         " of the AAL5 CPCS-PDU may contain the Frame Relay C/R bit."
1868                                         " The ingress router copies this bit here."
1869                                                                                         ,HFILL }}
1870                 ,{ &hf_pref_cw_rsv      ,{"Reserved bits"               ,"pw.cw.rsv"
1871                                         ,FT_UINT8       ,BASE_DEC       ,NULL           ,0xc0
1872                                         ,NULL                                           ,HFILL }}
1873                 ,{ &hf_generic_cw_rsv   ,{"Reserved bits"               ,"pw.cw.rsv"
1874                                         ,FT_UINT8       ,BASE_DEC       ,NULL           ,0x0f
1875                                         ,NULL                                           ,HFILL }}
1876                 ,{ &hf_pref_cw_len      ,{"Length"                      ,"pw.cw.length"
1877                                         ,FT_UINT8       ,BASE_DEC       ,NULL           ,0x3f
1878                                         ,NULL                                           ,HFILL }}
1879                 ,{ &hf_pref_cw_rsvlen   ,{"Length (extended)"           ,"pw.cw.length"
1880                                         ,FT_UINT8       ,BASE_DEC       ,NULL           ,0xff
1881                                         ,NULL                                           ,HFILL }}
1882                 ,{ &hf_cw_seq           ,{"Sequence number"             ,"pw.cw.seqno"
1883                                         ,FT_UINT16      ,BASE_DEC       ,NULL           ,0
1884                                         ,NULL                                           ,HFILL }}
1885                 ,{ &hf_gen_cw_atmbyte   ,{"ATM-specific byte"           ,"pw.cw.3rd_byte"
1886                                         ,FT_UINT8       ,BASE_HEX       ,NULL           ,0xFF
1887                                         ,NULL                                           ,HFILL }}
1888         };
1889         static gint *ett_array[] = {
1890                 &ett_encaps
1891                 ,&ett_cw
1892                 ,&ett_cell_header
1893                 ,&ett_cell
1894         };
1895
1896         proto_n1_cw =
1897                 proto_register_protocol(pwc_longname_pw_atm_n1_cw
1898                                         ,shortname_n1_cw
1899                                         ,"mplspwatmn1cw");
1900         proto_11_or_aal5_pdu =
1901                 proto_register_protocol(pwc_longname_pw_atm_11_or_aal5_pdu
1902                                         ,shortname_11_or_aal5_pdu
1903                                         ,"mplspwatm11_or_aal5pdu");
1904         proto_aal5_sdu =
1905                 proto_register_protocol(pwc_longname_pw_atm_aal5_sdu
1906                                         ,shortname_aal5_sdu
1907                                         ,"mplspwatmaal5sdu");
1908         proto_n1_nocw =
1909                 proto_register_protocol(pwc_longname_pw_atm_n1_nocw
1910                                         ,shortname_n1_nocw
1911                                         ,"mplspwatmn1nocw");
1912         proto_control_word =
1913                 proto_register_protocol("MPLS PW ATM Control Word"
1914                                         ,"MPLS PW ATM Control Word"
1915                                         ,"mplspwatmcontrolword");
1916         proto_cell_header =
1917                 proto_register_protocol("MPLS PW ATM Cell Header"
1918                                         ,"MPLS PW ATM Cell Header"
1919                                         ,"mplspwatmcellheader");
1920         proto_cell =
1921                 proto_register_protocol("ATM Cell"
1922                                         ,"ATM Cell"
1923                                         ,"mplspwatmcell");
1924
1925         proto_register_field_array( proto_cell                  ,hfa_cell       ,array_length(hfa_cell));
1926         proto_register_field_array( proto_cell_header           ,hfa_cell_header,array_length(hfa_cell_header));
1927         proto_register_field_array( proto_control_word          ,hfa_cw         ,array_length(hfa_cw));
1928         proto_register_field_array( proto_n1_nocw               ,hfa_n1_nocw    ,array_length(hfa_n1_nocw));
1929         proto_register_field_array( proto_n1_cw                 ,hfa_n1_cw      ,array_length(hfa_n1_cw));
1930         proto_register_field_array( proto_11_or_aal5_pdu        ,hfa_11_aal5pdu ,array_length(hfa_11_aal5pdu));
1931         proto_register_field_array( proto_aal5_sdu              ,hfa_aal5_sdu   ,array_length(hfa_aal5_sdu));
1932
1933         proto_register_subtree_array(ett_array, array_length(ett_array));
1934
1935         register_dissector("mpls_pw_atm_aal5_sdu"       ,dissect_aal5_sdu       ,proto_aal5_sdu);
1936         register_dissector("mpls_pw_atm_11_or_aal5_pdu" ,dissect_11_or_aal5_pdu ,proto_11_or_aal5_pdu);
1937         register_dissector("mpls_pw_atm_n1_cw"          ,dissect_n1_cw          ,proto_n1_cw);
1938         register_dissector("mpls_pw_atm_n1_nocw"        ,dissect_n1_nocw        ,proto_n1_nocw);
1939         register_dissector("mpls_pw_atm_control_word"   ,dissect_control_word   ,proto_control_word);
1940         new_register_dissector("mpls_pw_atm_cell"       ,dissect_cell           ,proto_cell);
1941         new_register_dissector("mpls_pw_atm_cell_header",dissect_cell_header    ,proto_cell_header);
1942         {
1943                 static const char description_allow_cw_length_nonzero[] =
1944                         "Enable to allow non-zero Length in Control Word."
1945                         " This may be needed to correctly decode traffic from some legacy devices"
1946                         " which generate non-zero Length even if there is no padding in the packet."
1947                         " Note that Length should have proper value (dissector checks this anyway)."
1948                         "\n\n"
1949                         "Disable to blame all packets with CW.Length <> 0. This conforms to RFC4717."
1950                         ;
1951                 static const char description_extend_cw_length_with_rsvd[] =
1952                         "Enable to use reserved bits (8..9) of Control Word as an extension of CW.Length."
1953                         " This may be needed to correctly decode traffic from some legacy devices"
1954                         " which uses reserved bits as extension of Length"
1955                         "\n\n"
1956                         "Disable to blame all packets with CW.Reserved <> 0. This conforms to RFC4717."
1957                         ;
1958                 module_t * module_n1_cw;
1959                 module_t * module_aal5_sdu;
1960
1961                 module_n1_cw = prefs_register_protocol(proto_n1_cw,NULL);
1962                 prefs_register_bool_preference(module_n1_cw
1963                         ,"allow_cw_length_nonzero"
1964                         ,"Allow CW.Length <> 0"
1965                         ,&description_allow_cw_length_nonzero[0]
1966                         ,&pref_n1_cw_allow_cw_length_nonzero);
1967                 prefs_register_bool_preference(module_n1_cw
1968                         ,"extend_cw_length_with_rsvd"
1969                         ,"Use CW.Reserved as extension of CW.Length"
1970                         ,&description_extend_cw_length_with_rsvd[0]
1971                         ,&pref_n1_cw_extend_cw_length_with_rsvd);
1972
1973                 module_aal5_sdu = prefs_register_protocol(proto_aal5_sdu,NULL);
1974                 prefs_register_bool_preference(module_aal5_sdu
1975                         ,"allow_cw_length_nonzero_aal5"
1976                         ,"Allow CW.Length <> 0"
1977                         ,&description_allow_cw_length_nonzero[0]
1978                         ,&pref_aal5_sdu_allow_cw_length_nonzero);
1979                 prefs_register_bool_preference(module_aal5_sdu
1980                         ,"extend_cw_length_with_rsvd_aal5"
1981                         ,"Use CW.Reserved as extension of CW.Length"
1982                         ,&description_extend_cw_length_with_rsvd[0]
1983                         ,&pref_aal5_sdu_extend_cw_length_with_rsvd);
1984         }
1985 }
1986
1987
1988 void proto_reg_handoff_pw_atm_ata(void)
1989 {
1990         dissector_handle_t h;
1991         h = find_dissector("mpls_pw_atm_n1_cw");
1992         dissector_add( "mpls.label", LABEL_INVALID, h );
1993         h = find_dissector("mpls_pw_atm_n1_nocw");
1994         dissector_add( "mpls.label", LABEL_INVALID, h );
1995         h = find_dissector("mpls_pw_atm_11_or_aal5_pdu");
1996         dissector_add( "mpls.label", LABEL_INVALID, h );
1997         h = find_dissector("mpls_pw_atm_aal5_sdu");
1998         dissector_add( "mpls.label", LABEL_INVALID, h );
1999
2000         dh_cell = find_dissector("mpls_pw_atm_cell");
2001         dh_cell_header = find_dissector("mpls_pw_atm_cell_header");
2002         dh_control_word = find_dissector("mpls_pw_atm_control_word");
2003         dh_atm_truncated = find_dissector("atm_truncated");
2004         dh_atm_untruncated = find_dissector("atm_untruncated");
2005         dh_atm_oam_cell = find_dissector("atm_oam_cell");
2006         dh_padding = find_dissector("pw_padding");
2007         dh_data = find_dissector("data");
2008 }