packet-q931.c

   1 /* packet-q931.c
   2  * Routines for Q.931 frame disassembly
   3  * Guy Harris <guy@alum.mit.edu>
   4  *
   5  * $Id: packet-q931.c,v 1.49 2002/11/09 08:09:18 guy Exp $
   6  *
   7  * Modified by Andreas Sikkema for possible use with H.323
   8  *
   9  * Ethereal - Network traffic analyzer
  10  * By Gerald Combs <gerald@ethereal.com>
  11  * Copyright 1998
  12  *
  13  * This program is free software; you can redistribute it and/or
  14  * modify it under the terms of the GNU General Public License
  15  * as published by the Free Software Foundation; either version 2
  16  * of the License, or (at your option) any later version.
  17  *
  18  * This program is distributed in the hope that it will be useful,
  19  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  20  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  21  * GNU General Public License for more details.
  22  *
  23  * You should have received a copy of the GNU General Public License
  24  * along with this program; if not, write to the Free Software
  25  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  26  */
  27
  28 #ifdef HAVE_CONFIG_H
  29 # include "config.h"
  30 #endif
  31
  32 #include <stdio.h>
  33 #include <glib.h>
  34 #include <string.h>
  35 #include <epan/packet.h>
  36 #include <epan/strutil.h>
  37 #include "nlpid.h"
  38 #include "packet-q931.h"
  39 #include "prefs.h"
  40
  41 #include "packet-tpkt.h"
  42
  43 /* Q.931 references:
  44  *
  45  * http://www.acacia-net.com/Clarinet/Protocol/q9313svn.htm
  46  * http://www.acacia-net.com/Clarinet/Protocol/q9311sc3.htm
  47  * http://www.acacia-net.com/Clarinet/Protocol/q9317oz7.htm
  48  * http://www.protocols.com/pbook/isdn.htm
  49  * http://freesoft.org/CIE/Topics/126.htm
  50  * http://noc.comstar.ru/miscdocs/ascend-faq-cause-codes.html
  51  * http://www.andrews-arnold.co.uk/isdn/q931cause.html
  52  * http://www.tulatelecom.ru/staff/german/DSSHelp/MessList/InfEl/InfElList.html
  53  */
  54
  55 static int proto_q931 = -1;
  56 static int hf_q931_discriminator = -1;
  57 static int hf_q931_call_ref_len = -1;
  58 static int hf_q931_call_ref_flag = -1;
  59 static int hf_q931_call_ref = -1;
  60 static int hf_q931_message_type = -1;
  61
  62 static gint ett_q931 = -1;
  63 static gint ett_q931_ie = -1;
  64
  65 /* desegmentation of Q.931 over TPKT over TCP */
  66 static gboolean q931_desegment = TRUE;
  67
  68 static dissector_handle_t h225_handle;
  69 static dissector_handle_t q931_tpkt_pdu_handle;
  70
  71 /*
  72  * Q.931 message types.
  73  */
  74 #define Q931_ESCAPE             0x00
  75 #define Q931_ALERTING           0x01
  76 #define Q931_CALL_PROCEEDING    0x02
  77 #define Q931_CONNECT            0x07
  78 #define Q931_CONNECT_ACK        0x0F
  79 #define Q931_PROGRESS           0x03
  80 #define Q931_SETUP              0x05
  81 #define Q931_SETUP_ACK          0x0D
  82 #define Q931_HOLD               0x24
  83 #define Q931_HOLD_ACK           0x28
  84 #define Q931_HOLD_REJECT        0x30
  85 #define Q931_RESUME             0x26
  86 #define Q931_RESUME_ACK         0x2E
  87 #define Q931_RESUME_REJECT      0x22
  88 #define Q931_RETRIEVE           0x31
  89 #define Q931_RETRIEVE_ACK       0x33
  90 #define Q931_RETRIEVE_REJECT    0x37
  91 #define Q931_SUSPEND            0x25
  92 #define Q931_SUSPEND_ACK        0x2D
  93 #define Q931_SUSPEND_REJECT     0x21
  94 #define Q931_USER_INFORMATION   0x20
  95 #define Q931_DISCONNECT         0x45
  96 #define Q931_RELEASE            0x4D
  97 #define Q931_RELEASE_COMPLETE   0x5A
  98 #define Q931_RESTART            0x46
  99 #define Q931_RESTART_ACK        0x4E
 100 #define Q931_CONGESTION_CONTROL 0x79
 101 #define Q931_FACILITY           0x62
 102 #define Q931_INFORMATION        0x7B
 103 #define Q931_NOTIFY             0x6E
 104 #define Q931_REGISTER           0x64
 105 #define Q931_SEGMENT            0x60
 106 #define Q931_STATUS             0x7D
 107 #define Q931_STATUS_ENQUIRY     0x75
 108
 109 static const value_string q931_message_type_vals[] = {
 110         { Q931_ESCAPE,                  "ESCAPE" },
 111         { Q931_ALERTING,                "ALERTING" },
 112         { Q931_CALL_PROCEEDING,         "CALL PROCEEDING" },
 113         { Q931_CONNECT,                 "CONNECT" },
 114         { Q931_CONNECT_ACK,             "CONNECT ACKNOWLEDGE" },
 115         { Q931_PROGRESS,                "PROGRESS" },
 116         { Q931_SETUP,                   "SETUP" },
 117         { Q931_SETUP_ACK,               "SETUP ACKNOWLEDGE" },
 118         { Q931_HOLD,                    "HOLD" },
 119         { Q931_HOLD_ACK,                "HOLD_ACKNOWLEDGE" },
 120         { Q931_HOLD_REJECT,             "HOLD_REJECT" },
 121         { Q931_RESUME,                  "RESUME" },
 122         { Q931_RESUME_ACK,              "RESUME ACKNOWLEDGE" },
 123         { Q931_RESUME_REJECT,           "RESUME REJECT" },
 124         { Q931_RETRIEVE,                "RETRIEVE" },
 125         { Q931_RETRIEVE_ACK,            "RETRIEVE ACKNOWLEDGE" },
 126         { Q931_RETRIEVE_REJECT,         "RETRIEVE REJECT" },
 127         { Q931_SUSPEND,                 "SUSPEND" },
 128         { Q931_SUSPEND_ACK,             "SUSPEND ACKNOWLEDGE" },
 129         { Q931_SUSPEND_REJECT,          "SUSPEND REJECT" },
 130         { Q931_USER_INFORMATION,        "USER INFORMATION" },
 131         { Q931_DISCONNECT,              "DISCONNECT" },
 132         { Q931_RELEASE,                 "RELEASE" },
 133         { Q931_RELEASE_COMPLETE,        "RELEASE COMPLETE" },
 134         { Q931_RESTART,                 "RESTART" },
 135         { Q931_RESTART_ACK,             "RESTART ACKNOWLEDGE" },
 136         { Q931_CONGESTION_CONTROL,      "CONGESTION CONTROL" },
 137         { Q931_FACILITY,                "FACILITY" },
 138         { Q931_INFORMATION,             "INFORMATION" },
 139         { Q931_NOTIFY,                  "NOTIFY" },
 140         { Q931_REGISTER,                "REGISTER" },
 141         { Q931_SEGMENT,                 "SEGMENT" },
 142         { Q931_STATUS,                  "STATUS" },
 143         { Q931_STATUS_ENQUIRY,          "STATUS ENQUIRY" },
 144         { 0,                            NULL }
 145 };
 146
 147 static const true_false_string tfs_call_ref_flag = {
 148         "Message sent to originating side",
 149         "Message sent from originating side"
 150 };
 151
 152 /*
 153  * Information elements.
 154  */
 155
 156 /*
 157  * Single-octet IEs.
 158  */
 159 #define Q931_IE_SO_IDENTIFIER_MASK      0xf0    /* IE identifier mask */
 160 #define Q931_IE_SO_IDENTIFIER_SHIFT     4       /* IE identifier shift */
 161 #define Q931_IE_SO_IE_MASK              0x0F    /* IE mask */
 162
 163 #define Q931_IE_SHIFT                   0x90
 164 #define Q931_IE_SHIFT_LOCKING           0x08    /* locking shift */
 165 #define Q931_IE_SHIFT_CODESET           0x0F    /* codeset */
 166
 167 #define Q931_IE_MORE_DATA_OR_SEND_COMP  0xA0    /* More Data or Sending Complete */
 168 #define Q931_IE_MORE_DATA               0xA0
 169 #define Q931_IE_SENDING_COMPLETE        0xA1
 170
 171 #define Q931_IE_CONGESTION_LEVEL        0xB0
 172 #define Q931_IE_REPEAT_INDICATOR        0xD0
 173
 174 /*
 175  * Variable-length IEs.
 176  */
 177 #define Q931_IE_VL_EXTENSION            0x80    /* Extension flag */
 178
 179 /*
 180  * Codeset 0 (default).
 181  */
 182 #define Q931_IE_SEGMENTED_MESSAGE       0x00
 183 #define Q931_IE_BEARER_CAPABILITY       0x04
 184 #define Q931_IE_CAUSE                   0x08
 185 #define Q931_IE_CALL_IDENTITY           0x10
 186 #define Q931_IE_CALL_STATE              0x14
 187 #define Q931_IE_CHANNEL_IDENTIFICATION  0x18
 188 #define Q931_IE_FACILITY                0x1C
 189 #define Q931_IE_PROGRESS_INDICATOR      0x1E
 190 #define Q931_IE_NETWORK_SPECIFIC_FACIL  0x20    /* Network Specific Facilities */
 191 #define Q931_IE_NOTIFICATION_INDICATOR  0x27
 192 #define Q931_IE_DISPLAY                 0x28
 193 #define Q931_IE_DATE_TIME               0x29
 194 #define Q931_IE_KEYPAD_FACILITY         0x2C
 195 #define Q931_IE_INFORMATION_REQUEST     0x32
 196 #define Q931_IE_SIGNAL                  0x34
 197 #define Q931_IE_SWITCHHOOK              0x36
 198 #define Q931_IE_FEATURE_ACTIVATION      0x38
 199 #define Q931_IE_FEATURE_INDICATION      0x39
 200 #define Q931_IE_ENDPOINT_IDENTIFIER     0x3B
 201 #define Q931_IE_SERVICE_PROFILE_ID      0x3A
 202 #define Q931_IE_INFORMATION_RATE        0x40
 203 #define Q931_IE_E2E_TRANSIT_DELAY       0x42    /* End-to-end Transit Delay */
 204 #define Q931_IE_TD_SELECTION_AND_INT    0x43    /* Transit Delay Selection and Indication */
 205 #define Q931_IE_PL_BINARY_PARAMETERS    0x44    /* Packet layer binary parameters */
 206 #define Q931_IE_PL_WINDOW_SIZE          0x45    /* Packet layer window size */
 207 #define Q931_IE_PACKET_SIZE             0x46    /* Packet size */
 208 #define Q931_IE_CUG                     0x47    /* Closed user group */
 209 #define Q931_IE_REVERSE_CHARGE_IND      0x4A    /* Reverse charging indication */
 210 #define Q931_IE_CONNECTED_NUMBER_DEFAULT        0x4C    /* Connected Number */
 211 #define Q931_IE_CALLING_PARTY_NUMBER    0x6C    /* Calling Party Number */
 212 #define Q931_IE_CALLING_PARTY_SUBADDR   0x6D    /* Calling Party Subaddress */
 213 #define Q931_IE_CALLED_PARTY_NUMBER     0x70    /* Called Party Number */
 214 #define Q931_IE_CALLED_PARTY_SUBADDR    0x71    /* Called Party Subaddress */
 215 #define Q931_IE_REDIRECTING_NUMBER      0x74
 216 #define Q931_IE_REDIRECTION_NUMBER      0x76
 217 #define Q931_IE_TRANSIT_NETWORK_SEL     0x78    /* Transit Network Selection */
 218 #define Q931_IE_RESTART_INDICATOR       0x79
 219 #define Q931_IE_LOW_LAYER_COMPAT        0x7C    /* Low-Layer Compatibility */
 220 #define Q931_IE_HIGH_LAYER_COMPAT       0x7D    /* High-Layer Compatibility */
 221 #define Q931_IE_USER_USER               0x7E    /* User-User */
 222 #define Q931_IE_ESCAPE                  0x7F    /* Escape for extension */
 223
 224 /*
 225  * Codeset 0 ETSI.
 226  */
 227 #define Q931_IE_CONNECTED_NUMBER        0x8C
 228 #define Q931_IE_CONNECTED_SUBADDR       0x8D
 229
 230 /*
 231  * Codeset 5 (National-specific) Belgium.
 232  */
 233 #define Q931_IE_CHARGING_ADVICE         0x1A
 234
 235 /*
 236  * Codeset 5 (National-specific) Bellcore National ISDN.
 237  */
 238 #define Q931_IE_OPERATOR_SYSTEM_ACCESS  0x1D
 239
 240 /*
 241  * Codeset 6 (Network-specific) Belgium.
 242  */
 243 /* 0x1A is Charging Advice, as with Codeset 5 */
 244 #define Q931_IE_REDIRECTING_NUMBER      0x74
 245
 246 /*
 247  * Codeset 6 (Network-specific) FT-Numeris.
 248  */
 249 /* 0x1D is User Capability */
 250
 251 /*
 252  * Codeset 6 (Network-specific) Bellcore National ISDN.
 253  */
 254 #define Q931_IE_REDIRECTING_SUBADDR     0x75    /* Redirecting Subaddress */
 255 /* 0x76 is Redirection Number, but that's also Codeset 0 */
 256 #define Q931_IE_CALL_APPEARANCE         0x7B
 257
 258 static const value_string q931_info_element_vals[] = {
 259         { Q931_IE_SEGMENTED_MESSAGE,            "Segmented message" },
 260         { Q931_IE_BEARER_CAPABILITY,            "Bearer capability" },
 261         { Q931_IE_CAUSE,                        "Cause" },
 262         { Q931_IE_CALL_IDENTITY,                "Call identity" },
 263         { Q931_IE_CALL_STATE,                   "Call state" },
 264         { Q931_IE_CHANNEL_IDENTIFICATION,       "Channel identification" },
 265         { Q931_IE_FACILITY,                     "Facility" },
 266         { Q931_IE_PROGRESS_INDICATOR,           "Progress indicator" },
 267         { Q931_IE_NETWORK_SPECIFIC_FACIL,       "Network specific facilities" },
 268         { Q931_IE_NOTIFICATION_INDICATOR,       "Notification indicator" },
 269         { Q931_IE_DISPLAY,                      "Display" },
 270         { Q931_IE_DATE_TIME,                    "Date/Time" },
 271         { Q931_IE_KEYPAD_FACILITY,              "Keypad facility" },
 272         { Q931_IE_INFORMATION_REQUEST,          "Information request" },
 273         { Q931_IE_SIGNAL,                       "Signal" },
 274         { Q931_IE_SWITCHHOOK,                   "Switchhook" },
 275         { Q931_IE_FEATURE_ACTIVATION,           "Feature activation" },
 276         { Q931_IE_FEATURE_INDICATION,           "Feature Indication" },
 277         { Q931_IE_ENDPOINT_IDENTIFIER,          "Endpoint identifier" },
 278         { Q931_IE_SERVICE_PROFILE_ID,           "Service profile ID" },
 279         { Q931_IE_INFORMATION_RATE,             "Information rate" },
 280         { Q931_IE_E2E_TRANSIT_DELAY,            "End-to-end transit delay" },
 281         { Q931_IE_TD_SELECTION_AND_INT,         "Transit delay selection and indication" },
 282         { Q931_IE_PL_BINARY_PARAMETERS,         "Packet layer binary parameters" },
 283         { Q931_IE_PL_WINDOW_SIZE,               "Packet layer window size" },
 284         { Q931_IE_PACKET_SIZE,                  "Packet size" },
 285         { Q931_IE_CUG,                          "Closed user group" },
 286         { Q931_IE_REVERSE_CHARGE_IND,           "Reverse charging indication" },
 287         { Q931_IE_CONNECTED_NUMBER_DEFAULT,     "Connected number" },
 288         { Q931_IE_CALLING_PARTY_NUMBER,         "Calling party number" },
 289         { Q931_IE_CALLING_PARTY_SUBADDR,        "Calling party subaddress" },
 290         { Q931_IE_CALLED_PARTY_NUMBER,          "Called party number" },
 291         { Q931_IE_CALLED_PARTY_SUBADDR,         "Called party subaddress" },
 292         { Q931_IE_REDIRECTING_NUMBER,           "Redirecting number" },
 293         { Q931_IE_REDIRECTION_NUMBER,           "Redirection number" },
 294         { Q931_IE_TRANSIT_NETWORK_SEL,          "Transit network selection" },
 295         { Q931_IE_RESTART_INDICATOR,            "Restart indicator" },
 296         { Q931_IE_LOW_LAYER_COMPAT,             "Low-layer compatibility" },
 297         { Q931_IE_HIGH_LAYER_COMPAT,            "High-layer compatibility" },
 298         { Q931_IE_USER_USER,                    "User-user" },
 299         { Q931_IE_ESCAPE,                       "Escape" },
 300         { Q931_IE_CONNECTED_NUMBER,             "Connected number" },
 301         { Q931_IE_CONNECTED_SUBADDR,            "Connected subaddress" },
 302         { Q931_IE_CHARGING_ADVICE,              "Charging advice" },
 303         { Q931_IE_OPERATOR_SYSTEM_ACCESS,       "Operator system access" },
 304         { Q931_IE_REDIRECTING_NUMBER,           "Redirecting number" },
 305         { Q931_IE_REDIRECTING_SUBADDR,          "Redirecting subaddress" },
 306         { Q931_IE_CALL_APPEARANCE,              "Call appearance" },
 307         { 0,                                    NULL }
 308 };
 309
 310 static const value_string q931_congestion_level_vals[] = {
 311         { 0x0, "Receiver ready" },
 312         { 0xF, "Receiver not ready" },
 313         { 0,   NULL }
 314 };
 315
 316 static const value_string q931_repeat_indication_vals[] = {
 317         { 0x2, "Prioritized list" },
 318         { 0,   NULL }
 319 };
 320
 321 /*
 322  * ITU-standardized coding.
 323  */
 324 #define Q931_ITU_STANDARDIZED_CODING    0x00
 325
 326 /*
 327  * Dissect a Segmented message information element.
 328  */
 329 static void
 330 dissect_q931_segmented_message_ie(tvbuff_t *tvb, int offset, int len,
 331     proto_tree *tree)
 332 {
 333         if (len != 2) {
 334                 proto_tree_add_text(tree, tvb, offset, len,
 335                     "Segmented message: length is %d, should be 2\n", len);
 336                 return;
 337         }
 338         if (tvb_get_guint8(tvb, offset) & 0x80) {
 339                 proto_tree_add_text(tree, tvb, offset, 1,
 340                     "First segment: %u segments remaining",
 341                     tvb_get_guint8(tvb, offset) & 0x7F);
 342         } else {
 343                 proto_tree_add_text(tree, tvb, offset, 1,
 344                     "Not first segment: %u segments remaining",
 345                     tvb_get_guint8(tvb, offset) & 0x7F);
 346         }
 347         proto_tree_add_text(tree, tvb, offset + 1, 1,
 348             "Segmented message type: %u\n", tvb_get_guint8(tvb, offset + 1));
 349 }
 350
 351 /*
 352  * Dissect a Bearer capability or Low-layer compatibility information element.
 353  */
 354 static const value_string q931_bc_coding_standard_vals[] = {
 355         { 0x00, "ITU-T standardized coding" },
 356         { 0x20, "ISO/IEC standard" },
 357         { 0x40, "National standard" },
 358         { 0x60, "Standard defined for this particular network" },
 359         { 0,    NULL }
 360 };
 361
 362 static const value_string q931_information_transfer_capability_vals[] = {
 363         { 0x00, "Speech" },
 364         { 0x08, "Unrestricted digital information" },
 365         { 0x09, "Restricted digital information" },
 366         { 0x10, "3.1 kHz audio" },
 367         { 0x11, "Unrestricted digital information with tones/announcements" },
 368         { 0x18, "Video" },
 369         { 0,    NULL }
 370 };
 371
 372 static const value_string q931_transfer_mode_vals[] = {
 373         { 0x00, "Circuit mode" },
 374         { 0x40, "Packet mode" },
 375         { 0,    NULL }
 376 };
 377
 378 #define Q931_IT_RATE_MULTIRATE  0x18
 379
 380 static const value_string q931_information_transfer_rate_vals[] = {
 381         { 0x00,                         "Packet mode" },
 382         { 0x10,                         "64 kbit/s" },
 383         { 0x11,                         "2 x 64 kbit/s" },
 384         { 0x13,                         "384 kbit/s" },
 385         { 0x15,                         "1536 kbit/s" },
 386         { 0x17,                         "1920 kbit/s" },
 387         { Q931_IT_RATE_MULTIRATE,       "Multirate (64 kbit/s base rate)" },
 388         { 0,                            NULL }
 389 };
 390
 391 static const value_string q931_uil1_vals[] = {
 392         { 0x01, "V.110/I.460/X.30 rate adaption" },
 393         { 0x02, "Recommendation G.711 u-law" },
 394         { 0x03, "Recommendation G.711 A-law" },
 395         { 0x04, "Recommendation G.721 32 kbit/s ADPCM and Recommendation I.460" },
 396         { 0x05, "Recommendation H.221 and H.242" },
 397         { 0x06, "Recommendation H.223 and H.245" },
 398         { 0x07, "Non-ITU-T-standardized rate adaption" },
 399         { 0x08, "V.120 rate adaption" },
 400         { 0x09, "X.31 HDLC flag stuffing" },
 401         { 0,    NULL },
 402 };
 403
 404 static const value_string q931_l1_user_rate_vals[] = {
 405         { 0x00, "Rate indicated by E-bits" },
 406         { 0x01, "0.6 kbit/s" },
 407         { 0x02, "1.2 kbit/s" },
 408         { 0x03, "2.4 kbit/s" },
 409         { 0x04, "3.6 kbit/s" },
 410         { 0x05, "4.8 kbit/s" },
 411         { 0x06, "7.2 kbit/s" },
 412         { 0x07, "8 kbit/s" },
 413         { 0x08, "9.6 kbit/s" },
 414         { 0x09, "14.4 kbit/s" },
 415         { 0x0A, "16 kbit/s" },
 416         { 0x0B, "19.2 kbit/s" },
 417         { 0x0C, "32 kbit/s" },
 418         { 0x0E, "48 kbit/s" },
 419         { 0x0F, "56 kbit/s" },
 420         { 0x10, "64 kbit/s "},
 421         { 0x15, "0.1345 kbit/s" },
 422         { 0x16, "0.100 kbit/s" },
 423         { 0x17, "0.075/1.2 kbit/s" },
 424         { 0x18, "1.2/0.075 kbit/s" },
 425         { 0x19, "0.050 kbit/s" },
 426         { 0x1A, "0.075 kbit/s" },
 427         { 0x1B, "0.110 kbit/s" },
 428         { 0x1C, "0.150 kbit/s" },
 429         { 0x1D, "0.200 kbit/s" },
 430         { 0x1E, "0.300 kbit/s" },
 431         { 0x1F, "12 kbit/s" },
 432         { 0,    NULL }
 433 };
 434
 435 static const value_string q931_l1_intermediate_rate_vals[] = {
 436         { 0x20, "8 kbit/s" },
 437         { 0x40, "16 kbit/s" },
 438         { 0x60, "32 kbit/s" },
 439         { 0,    NULL }
 440 };
 441
 442 static const value_string q931_l1_stop_bits_vals[] = {
 443         { 0x20, "1" },
 444         { 0x40, "1.5" },
 445         { 0x60, "2" },
 446         { 0,    NULL }
 447 };
 448
 449 static const value_string q931_l1_data_bits_vals[] = {
 450         { 0x08, "5" },
 451         { 0x10, "7" },
 452         { 0x18, "8" },
 453         { 0,    NULL }
 454 };
 455
 456 static const value_string q931_l1_parity_vals[] = {
 457         { 0x00, "Odd" },
 458         { 0x02, "Even" },
 459         { 0x03, "None" },
 460         { 0x04, "Forced to 0" },
 461         { 0x05, "Forced to 1" },
 462         { 0,    NULL }
 463 };
 464
 465 static const value_string q931_l1_modem_type_vals[] = {
 466         { 0x11, "V.21" },
 467         { 0x12, "V.22" },
 468         { 0x13, "V.22 bis" },
 469         { 0x14, "V.23" },
 470         { 0x15, "V.26" },
 471         { 0x16, "V.26 bis" },
 472         { 0x17, "V.26 ter" },
 473         { 0x18, "V.27" },
 474         { 0x19, "V.27 bis" },
 475         { 0x1A, "V.27 ter" },
 476         { 0x1B, "V.29" },
 477         { 0x1C, "V.32" },
 478         { 0x1E, "V.34" },
 479         { 0,    NULL }
 480 };
 481
 482 #define Q931_UIL2_USER_SPEC     0x10
 483
 484 static const value_string q931_uil2_vals[] = {
 485         { 0x01,                 "Basic mode ISO 1745" },
 486         { 0x02,                 "Q.921/I.441" },        /* LAPD */
 487         { 0x06,                 "X.25, link layer" },   /* LAPB */
 488         { 0x07,                 "X.25 multilink" },     /* or 0x0F? */
 489         { 0x08,                 "T.71 Extended LAPB" },
 490         { 0x09,                 "HDLC ARM" },
 491         { 0x0A,                 "HDLC NRM" },
 492         { 0x0B,                 "HDLC ABM" },
 493         { 0x0C,                 "ISO 8802/2 LLC" },
 494         { 0x0D,                 "X.75 Single Link Procedure" },
 495         { 0x0E,                 "Q.922" },
 496         { 0x0F,                 "Core aspects of Q.922" },
 497         { Q931_UIL2_USER_SPEC,  "User-specified" },
 498         { 0x11,                 "ISO 7776 DTE-DTE operation" },
 499         { 0,                    NULL }
 500 };
 501
 502 static const value_string q931_mode_vals[] = {
 503         { 0x20, "Normal mode" },
 504         { 0x40, "Extended mode" },
 505         { 0,    NULL }
 506 };
 507
 508 #define Q931_UIL3_X25_PL        0x06
 509 #define Q931_UIL3_ISO_8208      0x07    /* X.25-based */
 510 #define Q931_UIL3_X223          0x08    /* X.25-based */
 511 #define Q931_UIL3_TR_9577       0x0B
 512 #define Q931_UIL3_USER_SPEC     0x10
 513
 514 static const value_string q931_uil3_vals[] = {
 515         { 0x02,                 "Q.931/I.451" },
 516         { Q931_UIL3_X25_PL,     "X.25, packet layer" },
 517         { Q931_UIL3_ISO_8208,   "ISO/IEC 8208" },
 518         { Q931_UIL3_X223,       "X.223/ISO 8878" },
 519         { 0x09,                 "ISO/IEC 8473" },
 520         { 0x0A,                 "T.70" },
 521         { Q931_UIL3_TR_9577,    "ISO/IEC TR 9577" },
 522         { Q931_UIL3_USER_SPEC,  "User-specified" },
 523         { 0,                    NULL }
 524 };
 525
 526 static void
 527 dissect_q931_protocol_discriminator(tvbuff_t *tvb, int offset, proto_tree *tree)
 528 {
 529         unsigned int discriminator = tvb_get_guint8(tvb, offset);
 530
 531         if (discriminator == NLPID_Q_931) {
 532                 proto_tree_add_uint_format(tree, hf_q931_discriminator,
 533                          tvb, offset, 1, discriminator,
 534                          "Protocol discriminator: Q.931");
 535         } else if (discriminator == NLPID_Q_2931) {
 536                 proto_tree_add_uint_format(tree, hf_q931_discriminator,
 537                          tvb, offset, 1, discriminator,
 538                          "Protocol discriminator: Q.2931");
 539         } else if ((discriminator >= 16 && discriminator < 63)
 540             || ((discriminator >= 80) && (discriminator < 254))) {
 541                 proto_tree_add_uint_format(tree, hf_q931_discriminator,
 542                     tvb, offset, 1, discriminator,
 543                     "Protocol discriminator: Network layer or layer 3 protocol (0x%02X)",
 544                     discriminator);
 545         } else if (discriminator >= 64 && discriminator <= 79) {
 546                 proto_tree_add_uint_format(tree, hf_q931_discriminator,
 547                     tvb, offset, 1, discriminator,
 548                     "Protocol discriminator: National use (0x%02X)",
 549                     discriminator);
 550         } else {
 551                 proto_tree_add_uint_format(tree, hf_q931_discriminator,
 552                     tvb, offset, 1, discriminator,
 553                     "Protocol discriminator: Reserved (0x%02X)",
 554                     discriminator);
 555         }
 556 }
 557
 558 void
 559 dissect_q931_bearer_capability_ie(tvbuff_t *tvb, int offset, int len,
 560     proto_tree *tree)
 561 {
 562         guint8 octet;
 563         guint8 coding_standard;
 564         guint8 it_rate;
 565         guint8 modem_type;
 566         guint8 uil2_protocol;
 567         guint8 uil3_protocol;
 568         guint8 add_l3_info;
 569
 570         if (len == 0)
 571                 return;
 572         octet = tvb_get_guint8(tvb, offset);
 573         coding_standard = octet & 0x60;
 574         proto_tree_add_text(tree, tvb, offset, 1,
 575             "Coding standard: %s",
 576             val_to_str(coding_standard, q931_bc_coding_standard_vals, NULL));
 577         if (coding_standard != Q931_ITU_STANDARDIZED_CODING) {
 578                 /*
 579                  * We don't know how the bearer capability is encoded,
 580                  * so just dump it as data and be done with it.
 581                  */
 582                 proto_tree_add_text(tree, tvb, offset,
 583                     len, "Data: %s",
 584                     tvb_bytes_to_str(tvb, offset, len));
 585                 return;
 586         }
 587         proto_tree_add_text(tree, tvb, offset, 1,
 588             "Information transfer capability: %s",
 589             val_to_str(octet & 0x1F, q931_information_transfer_capability_vals,
 590               "Unknown (0x%02X)"));
 591         offset += 1;
 592         len -= 1;
 593
 594         /*
 595          * XXX - only in Low-layer compatibility information element.
 596          */
 597         if (!(octet & Q931_IE_VL_EXTENSION)) {
 598                 if (len == 0)
 599                         return;
 600                 octet = tvb_get_guint8(tvb, offset);
 601                 proto_tree_add_text(tree, tvb, offset, 1,
 602                     "Out-band negotiation %spossible",
 603                     (octet & 0x40) ? "" : "not ");
 604                 offset += 1;
 605                 len -= 1;
 606         }
 607
 608         if (len == 0)
 609                 return;
 610         octet = tvb_get_guint8(tvb, offset);
 611         proto_tree_add_text(tree, tvb, offset, 1,
 612             "Transfer mode: %s",
 613             val_to_str(octet & 0x60, q931_transfer_mode_vals,
 614               "Unknown (0x%02X)"));
 615         it_rate = octet & 0x1F;
 616         proto_tree_add_text(tree, tvb, offset, 1,
 617             "Information transfer rate: %s",
 618             val_to_str(it_rate, q931_information_transfer_rate_vals,
 619               "Unknown (0x%02X)"));
 620         offset += 1;
 621         len -= 1;
 622
 623         if (it_rate == Q931_IT_RATE_MULTIRATE) {
 624                 if (len == 0)
 625                         return;
 626                 proto_tree_add_text(tree, tvb, offset, 1, "Rate multiplier: %u", tvb_get_guint8(tvb, offset));
 627                 offset += 1;
 628                 len -= 1;
 629         }
 630
 631         if (len == 0)
 632                 return;
 633         octet = tvb_get_guint8(tvb, offset);
 634         if ((octet & 0x60) == 0x20) {
 635                 /*
 636                  * Layer 1 information.
 637                  */
 638                 proto_tree_add_text(tree, tvb, offset, 1,
 639                     "User information layer 1 protocol: %s",
 640                     val_to_str(octet & 0x1F, q931_uil1_vals,
 641                       "Unknown (0x%02X)"));
 642                 offset += 1;
 643                 len -= 1;
 644
 645                 if (octet & Q931_IE_VL_EXTENSION)
 646                         goto l1_done;
 647                 if (len == 0)
 648                         return;
 649                 octet = tvb_get_guint8(tvb, offset);
 650                 proto_tree_add_text(tree, tvb, offset, 1,
 651                     "Layer 1 is %s",
 652                     (octet & 0x40) ? "Asynchronous" : "Synchronous");
 653                 proto_tree_add_text(tree, tvb, offset, 1,
 654                     "Layer 1 in-band negotiation is %spossible",
 655                     (octet & 0x20) ? "" : "not ");
 656                 proto_tree_add_text(tree, tvb, offset, 1,
 657                     "User rate: %s",
 658                     val_to_str(octet & 0x1F, q931_l1_user_rate_vals,
 659                       "Unknown (0x%02X)"));
 660                 offset += 1;
 661                 len -= 1;
 662
 663                 if (octet & Q931_IE_VL_EXTENSION)
 664                         goto l1_done;
 665                 if (len == 0)
 666                         return;
 667                 octet = tvb_get_guint8(tvb, offset);
 668                 proto_tree_add_text(tree, tvb, offset, 1,
 669                     "Intermediate rate: %s",
 670                       val_to_str(octet & 0x60, q931_l1_intermediate_rate_vals,
 671                        "Unknown (0x%X)"));
 672                 proto_tree_add_text(tree, tvb, offset, 1,
 673                     "%s to send data with network independent clock",
 674                     (octet & 0x10) ? "Required" : "Not required");
 675                 proto_tree_add_text(tree, tvb, offset, 1,
 676                     "%s accept data with network independent clock",
 677                     (octet & 0x08) ? "Can" : "Cannot");
 678                 proto_tree_add_text(tree, tvb, offset, 1,
 679                     "%s to send data with flow control mechanism",
 680                     (octet & 0x04) ? "Required" : "Not required");
 681                 proto_tree_add_text(tree, tvb, offset, 1,
 682                     "%s accept data with flow control mechanism",
 683                     (octet & 0x02) ? "Can" : "Cannot");
 684                 offset += 1;
 685                 len -= 1;
 686
 687                 if (octet & Q931_IE_VL_EXTENSION)
 688                         goto l1_done;
 689                 if (len == 0)
 690                         return;
 691                 octet = tvb_get_guint8(tvb, offset);
 692                 proto_tree_add_text(tree, tvb, offset, 1,
 693                     "Rate adaption header %sincluded",
 694                     (octet & 0x40) ? "" : "not ");
 695                 proto_tree_add_text(tree, tvb, offset, 1,
 696                     "Multiple frame establishment %ssupported",
 697                     (octet & 0x20) ? "" : "not ");
 698                 proto_tree_add_text(tree, tvb, offset, 1,
 699                     "%s mode of operation",
 700                     (octet & 0x10) ? "Protocol sensitive" : "Bit transparent");
 701                 proto_tree_add_text(tree, tvb, offset, 1,
 702                     (octet & 0x08) ?
 703                       "Full protocol negotiation" : "LLI = 256 only");
 704                 proto_tree_add_text(tree, tvb, offset, 1,
 705                     "Message originator is %s",
 706                     (octet & 0x04) ? "Assignor only" : "Default assignee");
 707                 proto_tree_add_text(tree, tvb, offset, 1,
 708                     "Negotiation is done %s",
 709                     (octet & 0x02) ? "in-band" : "out-of-band");
 710                 offset += 1;
 711                 len -= 1;
 712
 713                 if (octet & Q931_IE_VL_EXTENSION)
 714                         goto l1_done;
 715                 if (len == 0)
 716                         return;
 717                 octet = tvb_get_guint8(tvb, offset);
 718                 proto_tree_add_text(tree, tvb, offset, 1,
 719                     "Stop bits: %s",
 720                       val_to_str(octet & 0x60, q931_l1_stop_bits_vals,
 721                        "Unknown (0x%X)"));
 722                 proto_tree_add_text(tree, tvb, offset, 1,
 723                     "Data bits: %s",
 724                       val_to_str(octet & 0x18, q931_l1_data_bits_vals,
 725                        "Unknown (0x%X)"));
 726                 proto_tree_add_text(tree, tvb, offset, 1,
 727                     "Parity: %s",
 728                       val_to_str(octet & 0x08, q931_l1_parity_vals,
 729                        "Unknown (0x%X)"));
 730
 731                 if (octet & Q931_IE_VL_EXTENSION)
 732                         goto l1_done;
 733                 if (len == 0)
 734                         return;
 735                 octet = tvb_get_guint8(tvb, offset);
 736                 proto_tree_add_text(tree, tvb, offset, 1,
 737                     "%s duplex",
 738                     (octet & 0x40) ? "Full" : "Half");
 739                 modem_type = octet & 0x3F;
 740                 if (modem_type <= 0x5 ||
 741                     (modem_type >= 0x20 && modem_type <= 0x2F)) {
 742                         proto_tree_add_text(tree, tvb, offset, 1,
 743                             "Modem type: National use 0x%02X", modem_type);
 744                 } else if (modem_type >= 0x30) {
 745                         proto_tree_add_text(tree, tvb, offset, 1,
 746                             "Modem type: User specified 0x%02X", modem_type);
 747                 } else {
 748                         proto_tree_add_text(tree, tvb, offset, 1,
 749                             "Modem type: %s",
 750                               val_to_str(modem_type, q931_l1_modem_type_vals,
 751                               "Unknown (0x%02X)"));
 752                 }
 753                 offset += 1;
 754                 len -= 1;
 755         }
 756 l1_done:
 757         ;
 758
 759         if (len == 0)
 760                 return;
 761         octet = tvb_get_guint8(tvb, offset);
 762         if ((octet & 0x60) == 0x40) {
 763                 /*
 764                  * Layer 2 information.
 765                  */
 766                 uil2_protocol = octet & 0x1F;
 767                 proto_tree_add_text(tree, tvb, offset, 1,
 768                     "User information layer 2 protocol: %s",
 769                     val_to_str(uil2_protocol, q931_uil2_vals,
 770                       "Unknown (0x%02X)"));
 771                 offset += 1;
 772                 len -= 1;
 773
 774                 /*
 775                  * XXX - only in Low-layer compatibility information element.
 776                  */
 777                 if (octet & Q931_IE_VL_EXTENSION)
 778                         goto l2_done;
 779                 if (len == 0)
 780                         return;
 781                 octet = tvb_get_guint8(tvb, offset);
 782                 if (uil2_protocol == Q931_UIL2_USER_SPEC) {
 783                         proto_tree_add_text(tree, tvb, offset, 1,
 784                             "User-specified layer 2 protocol information: 0x%02X",
 785                             octet & 0x7F);
 786                 } else {
 787                         proto_tree_add_text(tree, tvb, offset, 1,
 788                             "Mode: %s",
 789                             val_to_str(octet & 0x60, q931_mode_vals,
 790                               "Unknown (0x%02X)"));
 791                 }
 792                 offset += 1;
 793                 len -= 1;
 794
 795                 if (octet & Q931_IE_VL_EXTENSION)
 796                         goto l2_done;
 797                 if (len == 0)
 798                         return;
 799                 octet = tvb_get_guint8(tvb, offset);
 800                 proto_tree_add_text(tree, tvb, offset, 1,
 801                     "Window size: %u k", octet & 0x7F);
 802                 offset += 1;
 803                 len -= 1;
 804         }
 805 l2_done:
 806         ;
 807
 808         if (len == 0)
 809                 return;
 810         octet = tvb_get_guint8(tvb, offset);
 811         if ((octet & 0x60) == 0x60) {
 812                 /*
 813                  * Layer 3 information.
 814                  */
 815                 uil3_protocol = octet & 0x1F;
 816                 proto_tree_add_text(tree, tvb, offset, 1,
 817                     "User information layer 3 protocol: %s",
 818                     val_to_str(uil3_protocol, q931_uil3_vals,
 819                       "Unknown (0x%02X)"));
 820                 offset += 1;
 821                 len -= 1;
 822
 823
 824                 /*
 825                  * XXX - only in Low-layer compatibility information element.
 826                  */
 827                 if (octet & Q931_IE_VL_EXTENSION)
 828                         goto l3_done;
 829                 if (len == 0)
 830                         return;
 831                 octet = tvb_get_guint8(tvb, offset);
 832                 switch (uil3_protocol) {
 833
 834                 case Q931_UIL3_X25_PL:
 835                 case Q931_UIL3_ISO_8208:
 836                 case Q931_UIL3_X223:
 837                         proto_tree_add_text(tree, tvb, offset, 1,
 838                             "Mode: %s",
 839                             val_to_str(octet & 0x60, q931_mode_vals,
 840                               "Unknown (0x%02X)"));
 841                         offset += 1;
 842                         len -= 1;
 843
 844                         if (octet & Q931_IE_VL_EXTENSION)
 845                                 goto l3_done;
 846                         if (len == 0)
 847                                 return;
 848                         octet = tvb_get_guint8(tvb, offset);
 849                         proto_tree_add_text(tree, tvb, offset, 1,
 850                             "Default packet size: %u", octet & 0x0F);
 851                         offset += 1;
 852                         len -= 1;
 853
 854                         if (octet & Q931_IE_VL_EXTENSION)
 855                                 goto l3_done;
 856                         if (len == 0)
 857                                 return;
 858                         octet = tvb_get_guint8(tvb, offset);
 859                         proto_tree_add_text(tree, tvb, offset, 1,
 860                             "Packet window size: %u", octet & 0x7F);
 861                         offset += 1;
 862                         len -= 1;
 863                         break;
 864
 865                 case Q931_UIL3_USER_SPEC:
 866                         proto_tree_add_text(tree, tvb, offset, 1,
 867                             "Default packet size: %u octets",
 868                             1 << (octet & 0x0F));
 869                         offset += 1;
 870                         len -= 1;
 871                         break;
 872
 873                 case Q931_UIL3_TR_9577:
 874                         add_l3_info = (octet & 0x0F) << 4;
 875                         if (octet & Q931_IE_VL_EXTENSION)
 876                                 goto l3_done;
 877                         if (len == 0)
 878                                 return;
 879                         octet = tvb_get_guint8(tvb, offset + 1);
 880                         add_l3_info |= (octet & 0x0F);
 881                         proto_tree_add_text(tree, tvb, offset, 2,
 882                             "Additional layer 3 protocol information: %s",
 883                             val_to_str(add_l3_info, nlpid_vals,
 884                               "Unknown (0x%02X)"));
 885                         offset += 2;
 886                         len -= 2;
 887                         break;
 888                 }
 889         }
 890 l3_done:
 891         ;
 892 }
 893
 894 /*
 895  * Dissect a Cause information element.
 896  */
 897 static const value_string q931_cause_coding_standard_vals[] = {
 898         { 0x00, "ITU-T standardized coding" },
 899         { 0x20, "ISO/IEC standard" },
 900         { 0x40, "National standard" },
 901         { 0x60, "Standard specific to identified location" },
 902         { 0,    NULL }
 903 };
 904
 905 const value_string q931_cause_location_vals[] = {
 906         { 0x00, "User (U)" },
 907         { 0x01, "Private network serving the local user (LPN)" },
 908         { 0x02, "Public network serving the local user (LN)" },
 909         { 0x03, "Transit network (TN)" },
 910         { 0x04, "Public network serving the remote user (RLN)" },
 911         { 0x05, "Private network serving the remote user (RPN)" },
 912         { 0x07, "International network (INTL)" },
 913         { 0x0A, "Network beyond interworking point (BI)" },
 914         { 0,    NULL }
 915 };
 916
 917 static const value_string q931_cause_recommendation_vals[] = {
 918         { 0x00, "Q.931" },
 919         { 0x03, "X.21" },
 920         { 0x04, "X.25" },
 921         { 0x05, "Q.1031/Q.1051" },
 922         { 0,    NULL }
 923 };
 924
 925 /*
 926  * Cause codes for Cause.
 927  */
 928 const value_string q931_cause_code_vals[] = {
 929         { 0x00, "Valid cause code not yet received" },
 930         { 0x01, "Unallocated (unassigned) number" },
 931         { 0x02, "No route to specified transit network" },
 932         { 0x03, "No route to destination" },
 933         { 0x04, "Send special information tone" },
 934         { 0x05, "Misdialled trunk prefix" },
 935         { 0x06, "Channel unacceptable" },
 936         { 0x07, "Call awarded and being delivered in an established channel" },
 937         { 0x08, "Prefix 0 dialed but not allowed" },
 938         { 0x09, "Prefix 1 dialed but not allowed" },
 939         { 0x0A, "Prefix 1 dialed but not required" },
 940         { 0x0B, "More digits received than allowed, call is proceeding" },
 941         { 0x10, "Normal call clearing" },
 942         { 0x11, "User busy" },
 943         { 0x12, "No user responding" },
 944         { 0x13, "No answer from user (user alerted)" },
 945         { 0x14, "Subscriber absent" },
 946         { 0x15, "Call rejected" },
 947         { 0x16, "Number changed" },
 948         { 0x17, "Reverse charging rejected" },
 949         { 0x18, "Call suspended" },
 950         { 0x19, "Call resumed" },
 951         { 0x1A, "Non-selected user clearing" },
 952         { 0x1B, "Destination out of order" },
 953         { 0x1C, "Invalid number format (incomplete number)" },
 954         { 0x1D, "Facility rejected" },
 955         { 0x1E, "Response to STATUS ENQUIRY" },
 956         { 0x1F, "Normal unspecified" },
 957         { 0x21, "Circuit out of order" },
 958         { 0x22, "No circuit/channel available" },
 959         { 0x23, "Destination unattainable" },
 960         { 0x25, "Degraded service" },
 961         { 0x26, "Network out of order" },
 962         { 0x27, "Transit delay range cannot be achieved" },
 963         { 0x28, "Throughput range cannot be achieved" },
 964         { 0x29, "Temporary failure" },
 965         { 0x2A, "Switching equipment congestion" },
 966         { 0x2B, "Access information discarded" },
 967         { 0x2C, "Requested circuit/channel not available" },
 968         { 0x2D, "Pre-empted" },
 969         { 0x2E, "Precedence call blocked" },
 970         { 0x2F, "Resources unavailable, unspecified" },
 971         { 0x31, "Quality of service unavailable" },
 972         { 0x32, "Requested facility not subscribed" },
 973         { 0x33, "Reverse charging not allowed" },
 974         { 0x34, "Outgoing calls barred" },
 975         { 0x35, "Outgoing calls barred within CUG" },
 976         { 0x36, "Incoming calls barred" },
 977         { 0x37, "Incoming calls barred within CUG" },
 978         { 0x38, "Call waiting not subscribed" },
 979         { 0x39, "Bearer capability not authorized" },
 980         { 0x3A, "Bearer capability not presently available" },
 981         { 0x3E, "Inconsistency in designated outgoing access information and subscriber class" },
 982         { 0x3F, "Service or option not available, unspecified" },
 983         { 0x41, "Bearer capability not implemented" },
 984         { 0x42, "Channel type not implemented" },
 985         { 0x43, "Transit network selection not implemented" },
 986         { 0x44, "Message not implemented" },
 987         { 0x45, "Requested facility not implemented" },
 988         { 0x46, "Only restricted digital information bearer capability is available" },
 989         { 0x4F, "Service or option not implemented, unspecified" },
 990         { 0x51, "Invalid call reference value" },
 991         { 0x52, "Identified channel does not exist" },
 992         { 0x53, "Call identity does not exist for suspended call" },
 993         { 0x54, "Call identity in use" },
 994         { 0x55, "No call suspended" },
 995         { 0x56, "Call having the requested call identity has been cleared" },
 996         { 0x57, "Called user not member of CUG" },
 997         { 0x58, "Incompatible destination" },
 998         { 0x59, "Non-existent abbreviated address entry" },
 999         { 0x5A, "Destination address missing, and direct call not subscribed" },
1000         { 0x5B, "Invalid transit network selection (national use)" },
1001         { 0x5C, "Invalid facility parameter" },
1002         { 0x5D, "Mandatory information element is missing" },
1003         { 0x5F, "Invalid message, unspecified" },
1004         { 0x60, "Mandatory information element is missing" },
1005         { 0x61, "Message type non-existent or not implemented" },
1006         { 0x62, "Message not compatible with call state or message type non-existent or not implemented" },
1007         { 0x63, "Information element nonexistant or not implemented" },
1008         { 0x64, "Invalid information element contents" },
1009         { 0x65, "Message not compatible with call state" },
1010         { 0x66, "Recovery on timer expiry" },
1011         { 0x67, "Parameter non-existent or not implemented - passed on" },
1012         { 0x6E, "Message with unrecognized parameter discarded" },
1013         { 0x6F, "Protocol error, unspecified" },
1014         { 0x7F, "Internetworking, unspecified" },
1015         { 0,    NULL }
1016 };
1017
1018 static void
1019 dissect_q931_cause_ie(tvbuff_t *tvb, int offset, int len,
1020     proto_tree *tree)
1021 {
1022         guint8 octet;
1023         guint8 coding_standard;
1024
1025         if (len == 0)
1026                 return;
1027         octet = tvb_get_guint8(tvb, offset);
1028         coding_standard = octet & 0x60;
1029         proto_tree_add_text(tree, tvb, offset, 1,
1030             "Coding standard: %s",
1031             val_to_str(coding_standard, q931_cause_coding_standard_vals, NULL));
1032         if (coding_standard != Q931_ITU_STANDARDIZED_CODING) {
1033                 /*
1034                  * We don't know how the cause is encoded,
1035                  * so just dump it as data and be done with it.
1036                  */
1037                 proto_tree_add_text(tree, tvb, offset,
1038                     len, "Data: %s",
1039                     tvb_bytes_to_str(tvb, offset, len));
1040                 return;
1041         }
1042         proto_tree_add_text(tree, tvb, offset, 1,
1043             "Location: %s",
1044             val_to_str(octet & 0x0F, q931_cause_location_vals,
1045               "Unknown (0x%X)"));
1046         offset += 1;
1047         len -= 1;
1048
1049         if (!(octet & Q931_IE_VL_EXTENSION)) {
1050                 if (len == 0)
1051                         return;
1052                 octet = tvb_get_guint8(tvb, offset);
1053                 proto_tree_add_text(tree, tvb, offset, 1,
1054                     "Recommendation: %s",
1055                     val_to_str(octet & 0x7F, q931_cause_recommendation_vals,
1056                       "Unknown (0x%02X)"));
1057                 offset += 1;
1058                 len -= 1;
1059         }
1060
1061         if (len == 0)
1062                 return;
1063         octet = tvb_get_guint8(tvb, offset);
1064         proto_tree_add_text(tree, tvb, offset, 1,
1065             "Cause value: %s",
1066             val_to_str(octet & 0x7F, q931_cause_code_vals,
1067               "Unknown (0x%02X)"));
1068         offset += 1;
1069         len -= 1;
1070
1071         if (len == 0)
1072                 return;
1073         proto_tree_add_text(tree, tvb, offset, len,
1074             "Diagnostics: %s",
1075             tvb_bytes_to_str(tvb, offset, len));
1076 }
1077
1078 /*
1079  * Dissect a Call state information element.
1080  */
1081 static const value_string q931_coding_standard_vals[] = {
1082         { 0x00, "ITU-T standardized coding" },
1083         { 0x20, "ISO/IEC standard" },
1084         { 0x40, "National standard" },
1085         { 0x60, "Standard defined for the network" },
1086         { 0,    NULL }
1087 };
1088
1089 static const value_string q931_call_state_vals[] = {
1090         { 0x00, "Null" },
1091         { 0x01, "Call initiated" },
1092         { 0x02, "Overlap sending" },
1093         { 0x03, "Outgoing call proceeding" },
1094         { 0x04, "Call delivered" },
1095         { 0x06, "Call present" },
1096         { 0x07, "Call received" },
1097         { 0x08, "Connect request" },
1098         { 0x09, "Incoming call proceeding" },
1099         { 0x0A, "Active" },
1100         { 0x0B, "Disconnect request" },
1101         { 0x0C, "Disconnect indication" },
1102         { 0x0F, "Suspend request" },
1103         { 0x12, "Resume request" },
1104         { 0x13, "Release request" },
1105         { 0x16, "Call abort"},
1106         { 0x19, "Overlap receiving" },
1107         { 0x3D, "Restart request" },
1108         { 0x3E, "Restart" },
1109         { 0,    NULL }
1110 };
1111
1112 static void
1113 dissect_q931_call_state_ie(tvbuff_t *tvb, int offset, int len,
1114     proto_tree *tree)
1115 {
1116         guint8 octet;
1117         guint8 coding_standard;
1118
1119         if (len == 0)
1120                 return;
1121         octet = tvb_get_guint8(tvb, offset);
1122         coding_standard = octet & 0x60;
1123         proto_tree_add_text(tree, tvb, offset, 1,
1124             "Coding standard: %s",
1125             val_to_str(coding_standard, q931_coding_standard_vals, NULL));
1126         if (coding_standard != Q931_ITU_STANDARDIZED_CODING) {
1127                 /*
1128                  * We don't know how the call state is encoded,
1129                  * so just dump it as data and be done with it.
1130                  */
1131                 proto_tree_add_text(tree, tvb, offset,
1132                     len, "Data: %s",
1133                     tvb_bytes_to_str(tvb, offset, len));
1134                 return;
1135         }
1136         proto_tree_add_text(tree, tvb, offset, 1,
1137             "Call state: %s",
1138             val_to_str(octet & 0x3F, q931_call_state_vals,
1139               "Unknown (0x%02X)"));
1140 }
1141
1142 /*
1143  * Dissect a Channel identification information element.
1144  */
1145 #define Q931_INTERFACE_IDENTIFIED       0x40
1146 #define Q931_NOT_BASIC_CHANNEL          0x20
1147
1148 static const value_string q931_basic_channel_selection_vals[] = {
1149         { 0x00, "No channel" },
1150         { 0x01, "B1 channel" },
1151         { 0x02, "B2 channel" },
1152         { 0x03, "Any channel" },
1153         { 0,    NULL }
1154 };
1155
1156 static const value_string q931_not_basic_channel_selection_vals[] = {
1157         { 0x00, "No channel" },
1158         { 0x01, "Channel indicated in following octets" },
1159         { 0x03, "Any channel" },
1160         { 0,    NULL }
1161 };
1162
1163 #define Q931_IS_SLOT_MAP                0x10
1164
1165 static const value_string q931_element_type_vals[] = {
1166         { 0x03, "B-channel units" },
1167         { 0x06, "H0-channel units" },
1168         { 0x08, "H11-channel units" },
1169         { 0x09, "H12-channel units" },
1170         { 0,    NULL }
1171 };
1172
1173 static void
1174 dissect_q931_channel_identification_ie(tvbuff_t *tvb, int offset, int len,
1175     proto_tree *tree)
1176 {
1177         guint8 octet;
1178         int identifier_offset;
1179         int identifier_len;
1180         guint8 coding_standard;
1181
1182         if (len == 0)
1183                 return;
1184         octet = tvb_get_guint8(tvb, offset);
1185         proto_tree_add_text(tree, tvb, offset, 1,
1186             "Interface %s identified",
1187             (octet & Q931_INTERFACE_IDENTIFIED) ? "explicitly" : "implicitly");
1188         proto_tree_add_text(tree, tvb, offset, 1,
1189             "%s interface",
1190             (octet & Q931_NOT_BASIC_CHANNEL) ? "Not basic" : "Basic");
1191         proto_tree_add_text(tree, tvb, offset, 1,
1192             "Indicated channel is %s",
1193             (octet & 0x08) ? "required" : "preferred");
1194         proto_tree_add_text(tree, tvb, offset, 1,
1195             "Indicated channel is %sthe D-channel",
1196             (octet & 0x04) ? "" : "not ");
1197         if (octet & Q931_NOT_BASIC_CHANNEL) {
1198                 proto_tree_add_text(tree, tvb, offset, 1,
1199                     "Channel selection: %s",
1200                     val_to_str(octet & 0x03, q931_not_basic_channel_selection_vals,
1201                       "Unknown (0x%X)"));
1202         } else {
1203                 proto_tree_add_text(tree, tvb, offset, 1,
1204                     "Channel selection: %s",
1205                     val_to_str(octet & 0x03, q931_basic_channel_selection_vals,
1206                       NULL));
1207         }
1208         offset += 1;
1209         len -= 1;
1210
1211         if (octet & Q931_INTERFACE_IDENTIFIED) {
1212                 identifier_offset = offset;
1213                 identifier_len = 0;
1214                 do {
1215                         if (len == 0)
1216                                 break;
1217                         octet = tvb_get_guint8(tvb, offset);
1218                         offset += 1;
1219                         len -= 1;
1220                         identifier_len++;
1221                 } while (!(octet & Q931_IE_VL_EXTENSION));
1222
1223                 /*
1224                  * XXX - do we want to strip off the 8th bit on the
1225                  * last octet of the interface identifier?
1226                  */
1227                 if (identifier_len != 0) {
1228                         proto_tree_add_text(tree, tvb, identifier_offset,
1229                             identifier_len, "Interface identifier: %s",
1230                             bytes_to_str(
1231                               tvb_get_ptr(tvb, identifier_offset, identifier_len),
1232                               identifier_len));
1233                 }
1234         }
1235
1236         if (octet & Q931_NOT_BASIC_CHANNEL) {
1237                 if (len == 0)
1238                         return;
1239                 octet = tvb_get_guint8(tvb, offset);
1240                 coding_standard = octet & 0x60;
1241                 proto_tree_add_text(tree, tvb, offset, 1,
1242                     "Coding standard: %s",
1243                     val_to_str(coding_standard, q931_coding_standard_vals,
1244                       NULL));
1245                 if (coding_standard != Q931_ITU_STANDARDIZED_CODING) {
1246                         /*
1247                          * We don't know how the channel identifier is
1248                          * encoded, so just dump it as data and be done
1249                          * with it.
1250                          */
1251                         proto_tree_add_text(tree, tvb, offset,
1252                             len, "Data: %s",
1253                             tvb_bytes_to_str(tvb, offset, len));
1254                         return;
1255                 }
1256                 proto_tree_add_text(tree, tvb, offset, 1,
1257                     "Channel is indicated by %s",
1258                     (octet & Q931_IS_SLOT_MAP) ? "slot map" : "number");
1259                 proto_tree_add_text(tree, tvb, offset, 1,
1260                     "%s type: %s",
1261                     (octet & Q931_IS_SLOT_MAP) ? "Map element" : "Channel",
1262                     val_to_str(octet & 0x0F, q931_element_type_vals,
1263                         "Unknown (0x%02X)"));
1264
1265                 /*
1266                  * XXX - dump the channel number or slot map.
1267                  */
1268         }
1269 }
1270
1271 /*
1272  * Dissect a Progress indicator information element.
1273  */
1274 static const value_string q931_progress_description_vals[] = {
1275         { 0x01, "Call is not end-to-end ISDN - progress information available in-band" },
1276         { 0x02, "Destination address is non-ISDN" },
1277         { 0x03, "Origination address is non-ISDN" },
1278         { 0x04, "Call has returned to the ISDN" },
1279         { 0x05, "Interworking has occurred and has resulted in a telecommunications service change" },
1280         { 0x08, "In-band information or an appropriate pattern is now available" },
1281         { 0,    NULL }
1282 };
1283
1284 void
1285 dissect_q931_progress_indicator_ie(tvbuff_t *tvb, int offset, int len,
1286     proto_tree *tree)
1287 {
1288         guint8 octet;
1289         guint8 coding_standard;
1290
1291         if (len == 0)
1292                 return;
1293         octet = tvb_get_guint8(tvb, offset);
1294         coding_standard = octet & 0x60;
1295         proto_tree_add_text(tree, tvb, offset, 1,
1296             "Coding standard: %s",
1297             val_to_str(coding_standard, q931_cause_coding_standard_vals, NULL));
1298         if (coding_standard != Q931_ITU_STANDARDIZED_CODING) {
1299                 /*
1300                  * We don't know how the progress indicator is encoded,
1301                  * so just dump it as data and be done with it.
1302                  */
1303                 proto_tree_add_text(tree, tvb, offset,
1304                     len, "Data: %s",
1305                     tvb_bytes_to_str(tvb, offset, len));
1306                 return;
1307         }
1308         proto_tree_add_text(tree, tvb, offset, 1,
1309             "Location: %s",
1310             val_to_str(octet & 0x0F, q931_cause_location_vals,
1311               "Unknown (0x%X)"));
1312         offset += 1;
1313         len -= 1;
1314
1315         if (len == 0)
1316                 return;
1317         octet = tvb_get_guint8(tvb, offset);
1318         proto_tree_add_text(tree, tvb, offset, 1,
1319             "Progress description: %s",
1320             val_to_str(octet & 0x7F, q931_progress_description_vals,
1321               "Unknown (0x%02X)"));
1322 }
1323
1324 /*
1325  * Dissect a Network-specific facilities or Transit network selection
1326  * information element.
1327  */
1328 static const value_string q931_netid_type_vals[] = {
1329         { 0x00, "User specified" },
1330         { 0x20, "National network identification" },
1331         { 0x30, "International network identification" },
1332         { 0,    NULL }
1333 };
1334
1335 static const value_string q931_netid_plan_vals[] = {
1336         { 0x00, "Unknown" },
1337         { 0x01, "Carrier Identification Code" },
1338         { 0x03, "X.121 data network identification code" },
1339         { 0,    NULL }
1340 };
1341
1342 static void
1343 dissect_q931_ns_facilities_ie(tvbuff_t *tvb, int offset, int len,
1344     proto_tree *tree)
1345 {
1346         guint8 octet;
1347         int netid_len;
1348
1349         if (len == 0)
1350                 return;
1351         octet = tvb_get_guint8(tvb, offset);
1352         netid_len = octet & 0x7F;
1353         proto_tree_add_text(tree, tvb, offset, 1,
1354             "Network identification length: %u",
1355             netid_len);
1356         offset += 1;
1357         len -= 1;
1358         if (netid_len != 0) {
1359                 if (len == 0)
1360                         return;
1361                 octet = tvb_get_guint8(tvb, offset);
1362                 proto_tree_add_text(tree, tvb, offset, 1,
1363                     "Type of network identification: %s",
1364                     val_to_str(octet & 0x70, q931_netid_type_vals,
1365                       "Unknown (0x%02X)"));
1366                 proto_tree_add_text(tree, tvb, offset, 1,
1367                     "Network identification plan: %s",
1368                     val_to_str(octet & 0x0F, q931_netid_plan_vals,
1369                       "Unknown (0x%02X)"));
1370                 offset += 1;
1371                 len -= 1;
1372                 netid_len--;
1373
1374                 if (len == 0)
1375                         return;
1376                 if (netid_len > len)
1377                         netid_len = len;
1378                 if (netid_len != 0) {
1379                         proto_tree_add_text(tree, tvb, offset, netid_len,
1380                             "Network identification: %s",
1381                             tvb_format_text(tvb, offset, netid_len));
1382                         offset += netid_len;
1383                         len -= netid_len;
1384                 }
1385         }
1386
1387         /*
1388          * Whatever is left is the network-specific facility
1389          * specification.
1390          */
1391          if (len == 0)
1392                 return;
1393         proto_tree_add_text(tree, tvb, offset,
1394             len, "Network-specific facility specification: %s",
1395             tvb_bytes_to_str(tvb, offset, len));
1396 }
1397
1398 /*
1399  * Dissect a Notification indicator information element.
1400  */
1401 static const value_string q931_notification_description_vals[] = {
1402         { 0x00, "User suspended" },
1403         { 0x01, "User resumed" },
1404         { 0x02, "Bearer service change" },
1405         { 0,    NULL }
1406 };
1407
1408 static void
1409 dissect_q931_notification_indicator_ie(tvbuff_t *tvb, int offset, int len,
1410     proto_tree *tree)
1411 {
1412         guint8 octet;
1413
1414         if (len == 0)
1415                 return;
1416         octet = tvb_get_guint8(tvb, offset);
1417         proto_tree_add_text(tree, tvb, offset, 1,
1418             "Notification description: %s",
1419             val_to_str(octet & 0x7F, q931_notification_description_vals,
1420               "Unknown (0x%02X)"));
1421 }
1422
1423 /*
1424  * Dissect a Date/time information element.
1425  */
1426 static void
1427 dissect_q931_date_time_ie(tvbuff_t *tvb, int offset, int len,
1428     proto_tree *tree)
1429 {
1430         if (len != 6) {
1431                 proto_tree_add_text(tree, tvb, offset, len,
1432                     "Date/time: length is %d, should be 6\n", len);
1433                 return;
1434         }
1435         /*
1436          * XXX - what is "year" relative to?  Is "month" 0-origin or
1437          * 1-origin?  Q.931 doesn't say....
1438          */
1439         proto_tree_add_text(tree, tvb, offset, 6,
1440             "Date/time: %02u-%02u-%02u %02u:%02u:%02u",
1441             tvb_get_guint8(tvb, offset + 0), tvb_get_guint8(tvb, offset + 1), tvb_get_guint8(tvb, offset + 2),
1442             tvb_get_guint8(tvb, offset + 3), tvb_get_guint8(tvb, offset + 4), tvb_get_guint8(tvb, offset + 5));
1443 }
1444
1445 /*
1446  * Dissect a Signal information element.
1447  */
1448 static const value_string q931_signal_vals[] = {
1449         { 0x00, "Dial tone on" },
1450         { 0x01, "Ring tone on" },
1451         { 0x02, "Intercept tone on" },
1452         { 0x03, "Network congestion tone on" }, /* "fast busy" */
1453         { 0x04, "Busy tone on" },
1454         { 0x05, "Confirm tone on" },
1455         { 0x06, "Answer tone on" },
1456         { 0x07, "Call waiting tone on" },
1457         { 0x08, "Off-hook warning tone on" },
1458         { 0x09, "Preemption tone on" },
1459         { 0x3F, "Tones off" },
1460         { 0x40, "Alerting on - pattern 0" },
1461         { 0x41, "Alerting on - pattern 1" },
1462         { 0x42, "Alerting on - pattern 2" },
1463         { 0x43, "Alerting on - pattern 3" },
1464         { 0x44, "Alerting on - pattern 4" },
1465         { 0x45, "Alerting on - pattern 5" },
1466         { 0x46, "Alerting on - pattern 6" },
1467         { 0x47, "Alerting on - pattern 7" },
1468         { 0x4F, "Alerting off" },
1469         { 0,    NULL }
1470 };
1471
1472 static void
1473 dissect_q931_signal_ie(tvbuff_t *tvb, int offset, int len,
1474     proto_tree *tree)
1475 {
1476         if (len != 1) {
1477                 proto_tree_add_text(tree, tvb, offset, len,
1478                     "Signal: length is %d, should be 1\n", len);
1479                 return;
1480         }
1481         proto_tree_add_text(tree, tvb, offset, 1,
1482             "Signal: %s",
1483             val_to_str(tvb_get_guint8(tvb, offset), q931_signal_vals,
1484                 "Unknown (0x%02X)"));
1485 }
1486
1487 /*
1488  * Dissect an Information rate information element.
1489  */
1490 static const value_string q931_throughput_class_vals[] = {
1491         { 0x03, "75 bit/s" },
1492         { 0x04, "150 bit/s" },
1493         { 0x05, "300 bit/s" },
1494         { 0x06, "600 bit/s" },
1495         { 0x07, "1200 bit/s" },
1496         { 0x08, "2400 bit/s" },
1497         { 0x09, "4800 bit/s" },
1498         { 0x0A, "9600 bit/s" },
1499         { 0x0B, "19200 bit/s" },
1500         { 0x0C, "48000 bit/s" },
1501         { 0x0D, "64000 bit/s" },
1502         { 0,    NULL }
1503 };
1504
1505 static void
1506 dissect_q931_information_rate_ie(tvbuff_t *tvb, int offset, int len,
1507     proto_tree *tree)
1508 {
1509         if (len != 4) {
1510                 proto_tree_add_text(tree, tvb, offset, len,
1511                     "Information rate: length is %d, should be 4\n", len);
1512                 return;
1513         }
1514         proto_tree_add_text(tree, tvb, offset + 0, 1,
1515             "Incoming information rate: %s",
1516             val_to_str(tvb_get_guint8(tvb, offset + 0) & 0x1F,
1517               q931_throughput_class_vals, "Unknown (0x%02X)"));
1518         proto_tree_add_text(tree, tvb, offset + 1, 1,
1519             "Outgoing information rate: %s",
1520             val_to_str(tvb_get_guint8(tvb, offset + 1) & 0x1F,
1521               q931_throughput_class_vals, "Unknown (0x%02X)"));
1522         proto_tree_add_text(tree, tvb, offset + 2, 1,
1523             "Minimum incoming information rate: %s",
1524             val_to_str(tvb_get_guint8(tvb, offset + 2) & 0x1F,
1525               q931_throughput_class_vals, "Unknown (0x%02X)"));
1526         proto_tree_add_text(tree, tvb, offset + 3, 1,
1527             "Minimum outgoing information rate: %s",
1528             val_to_str(tvb_get_guint8(tvb, offset + 3) & 0x1F,
1529               q931_throughput_class_vals, "Unknown (0x%02X)"));
1530 }
1531
1532 static int
1533 dissect_q931_guint16_value(tvbuff_t *tvb, int offset, int len,
1534     proto_tree *tree, char *label)
1535 {
1536         guint8 octet;
1537         guint16 value;
1538         int value_len;
1539
1540         value_len = 0;
1541
1542         octet = tvb_get_guint8(tvb, offset);
1543         if (octet & Q931_IE_VL_EXTENSION) {
1544                 /*
1545                  * Only one octet long - error.
1546                  */
1547                 goto bad_length;
1548         }
1549         value = (octet & 0x3) << 14;
1550         offset += 1;
1551         len -= 1;
1552         value_len++;
1553
1554         if (len == 0) {
1555                 /*
1556                  * We've reached the end of the information element - error.
1557                  */
1558                 goto past_end;
1559         }
1560         octet = tvb_get_guint8(tvb, offset);
1561         if (octet & Q931_IE_VL_EXTENSION) {
1562                 /*
1563                  * Only two octets long - error.
1564                  */
1565                 goto bad_length;
1566         }
1567         value |= (octet & 0x7F) << 7;
1568         offset += 1;
1569         len -= 1;
1570         value_len++;
1571
1572         if (len == 0) {
1573                 /*
1574                  * We've reached the end of the information element - error.
1575                  */
1576                 goto past_end;
1577         }
1578         octet = tvb_get_guint8(tvb, offset);
1579         if (!(octet & Q931_IE_VL_EXTENSION)) {
1580                 /*
1581                  * More than three octets long - error.
1582                  */
1583                 goto bad_length;
1584         }
1585         value |= (octet & 0x7F);
1586         offset += 1;
1587         len -= 1;
1588         value_len++;
1589
1590         proto_tree_add_text(tree, tvb, offset, value_len, "%s: %u ms", label,
1591             value);
1592         return value_len;
1593
1594 past_end:
1595         proto_tree_add_text(tree, tvb, offset, len,
1596             "%s goes past end of information element", label);
1597         return -1;
1598
1599 bad_length:
1600         proto_tree_add_text(tree, tvb, offset, len, "%s isn't 3 octets long",
1601             label);
1602         return -1;
1603 }
1604
1605 /*
1606  * Dissect an End-to-end transit delay information element.
1607  */
1608 static void
1609 dissect_q931_e2e_transit_delay_ie(tvbuff_t *tvb, int offset, int len,
1610     proto_tree *tree)
1611 {
1612         int value_len;
1613
1614         if (len == 0)
1615                 return;
1616         value_len = dissect_q931_guint16_value(tvb, offset, len, tree,
1617             "Cumulative transit delay");
1618         if (value_len < 0)
1619                 return; /* error */
1620         offset += value_len;
1621         len -= value_len;
1622
1623         if (len == 0)
1624                 return;
1625         value_len = dissect_q931_guint16_value(tvb, offset, len, tree,
1626             "Requested end-to-end transit delay");
1627         if (value_len < 0)
1628                 return; /* error */
1629         offset += value_len;
1630         len -= value_len;
1631
1632         if (len == 0)
1633                 return;
1634         value_len = dissect_q931_guint16_value(tvb, offset, len, tree,
1635             "Maximum end-to-end transit delay");
1636 }
1637
1638 /*
1639  * Dissect a Transit delay selection and indication information element.
1640  */
1641 static void
1642 dissect_q931_td_selection_and_int_ie(tvbuff_t *tvb, int offset, int len,
1643     proto_tree *tree)
1644 {
1645         if (len == 0)
1646                 return;
1647         dissect_q931_guint16_value(tvb, offset, len, tree,
1648             "Transit delay");
1649 }
1650
1651 /*
1652  * Dissect a Packet layer binary parameters information element.
1653  */
1654 static const value_string q931_fast_selected_vals[] = {
1655         { 0x00, "Fast select not requested" },
1656         { 0x08, "Fast select not requested" },
1657         { 0x10, "Fast select requested with no restriction of response" },
1658         { 0x18, "Fast select requested with restrictions of response" },
1659         { 0x00, NULL }
1660 };
1661
1662 static void
1663 dissect_q931_pl_binary_parameters_ie(tvbuff_t *tvb, int offset, int len,
1664     proto_tree *tree)
1665 {
1666         guint8 octet;
1667
1668         if (len == 0)
1669                 return;
1670         octet = tvb_get_guint8(tvb, offset);
1671         proto_tree_add_text(tree, tvb, offset, 1,
1672             "Fast select: %s",
1673             val_to_str(octet & 0x18, q931_fast_selected_vals, NULL));
1674         proto_tree_add_text(tree, tvb, offset, 1,
1675             "%s",
1676             (octet & 0x04) ? "No request/request denied" :
1677                              "Request indicated/request accepted");
1678         proto_tree_add_text(tree, tvb, offset, 1,
1679             "%s confirmation",
1680             (octet & 0x02) ? "Link-by-link" : "End-to-end");
1681         proto_tree_add_text(tree, tvb, offset, 1,
1682             "Modulus %u sequencing",
1683             (octet & 0x01) ? 8 : 128);
1684 }
1685
1686 /*
1687  * Dissect a Packet layer window size information element.
1688  */
1689 static void
1690 dissect_q931_pl_window_size_ie(tvbuff_t *tvb, int offset, int len,
1691     proto_tree *tree)
1692 {
1693         if (len == 0)
1694                 return;
1695         proto_tree_add_text(tree, tvb, offset, 1,
1696             "Forward value: %u", tvb_get_guint8(tvb, offset) & 0x7F);
1697         offset += 1;
1698         len -= 1;
1699
1700         if (len == 0)
1701                 return;
1702         proto_tree_add_text(tree, tvb, offset, 1,
1703             "Backward value: %u", tvb_get_guint8(tvb, offset) & 0x7F);
1704 }
1705
1706 /*
1707  * Dissect a Packet size information element.
1708  */
1709 static void
1710 dissect_q931_packet_size_ie(tvbuff_t *tvb, int offset, int len,
1711     proto_tree *tree)
1712 {
1713         if (len == 0)
1714                 return;
1715         proto_tree_add_text(tree, tvb, offset, 1,
1716             "Forward value: %u", tvb_get_guint8(tvb, offset) & 0x7F);
1717         offset += 1;
1718         len -= 1;
1719
1720         if (len == 0)
1721                 return;
1722         proto_tree_add_text(tree, tvb, offset, 1,
1723             "Backward value: %u", tvb_get_guint8(tvb, offset) & 0x7F);
1724 }
1725
1726 /*
1727  * Dissect a Closed user group information element.
1728  */
1729 static const value_string q931_cug_indication_vals[] = {
1730         { 0x01, "Closed user group selection" },
1731         { 0x02, "Closed user group with outgoing access selection and indication" },
1732         { 0,    NULL }
1733 };
1734
1735 static void
1736 dissect_q931_cug_ie(tvbuff_t *tvb, int offset, int len, proto_tree *tree)
1737 {
1738         if (len == 0)
1739                 return;
1740         proto_tree_add_text(tree, tvb, offset, 1,
1741             "CUG indication: %s",
1742             val_to_str(tvb_get_guint8(tvb, offset) & 0x07,
1743               q931_cug_indication_vals, "Unknown (0x%02X)"));
1744         offset += 1;
1745         len -= 1;
1746
1747         if (len == 0)
1748                 return;
1749         proto_tree_add_text(tree, tvb, offset, len, "CUG index code: %s",
1750             tvb_format_text(tvb, offset, len));
1751 }
1752
1753 /*
1754  * Dissect a Reverse charging indication information element.
1755  */
1756 static const value_string q931_reverse_charging_indication_vals[] = {
1757         { 0x01, "Reverse charging requested" },
1758         { 0,    NULL }
1759 };
1760
1761 static void
1762 dissect_q931_reverse_charge_ind_ie(tvbuff_t *tvb, int offset, int len,
1763     proto_tree *tree)
1764 {
1765         if (len == 0)
1766                 return;
1767         proto_tree_add_text(tree, tvb, offset, 1,
1768             "Reverse charging indication: %s",
1769             val_to_str(tvb_get_guint8(tvb, offset) & 0x07,
1770               q931_reverse_charging_indication_vals, "Unknown (0x%02X)"));
1771 }
1772
1773 /*
1774  * Dissect a (phone) number information element.
1775  */
1776 static const value_string q931_number_type_vals[] = {
1777         { 0x00, "Unknown" },
1778         { 0x10, "International number" },
1779         { 0x20, "National number" },
1780         { 0x30, "Network specific number" },
1781         { 0x40, "Subscriber number" },
1782         { 0x60, "Abbreviated number" },
1783         { 0,    NULL }
1784 };
1785
1786 static const value_string q931_numbering_plan_vals[] = {
1787         { 0x00, "Unknown" },
1788         { 0x01, "E.164 ISDN/telephony numbering" },
1789         { 0x03, "X.121 data numbering" },
1790         { 0x04, "F.69 Telex numbering" },
1791         { 0x08, "National standard numbering" },
1792         { 0x09, "Private numbering" },
1793         { 0,    NULL }
1794 };
1795
1796 static const value_string q931_presentation_indicator_vals[] = {
1797         { 0x00, "Presentation allowed" },
1798         { 0x20, "Presentation restricted" },
1799         { 0x40, "Number not available due to interworking" },
1800         { 0,    NULL }
1801 };
1802
1803 static const value_string q931_screening_indicator_vals[] = {
1804         { 0x00, "User-provided, not screened" },
1805         { 0x01, "User-provided, verified and passed" },
1806         { 0x02, "User-provided, verified and failed" },
1807         { 0x03, "Network-provided" },
1808         { 0,    NULL }
1809 };
1810
1811 static const value_string q931_redirection_reason_vals[] = {
1812         { 0x00, "Unknown" },
1813         { 0x01, "Call forwarding busy or called DTE busy" },
1814         { 0x02, "Call forwarding no reply" },
1815         { 0x04, "Call deflection" },
1816         { 0x09, "Called DTE out of order" },
1817         { 0x0A, "Call forwarding by the called DTE" },
1818         { 0x0F, "Call forwarding unconditional or systematic call redirection" },
1819         { 0,    NULL }
1820 };
1821
1822 static void
1823 dissect_q931_number_ie(tvbuff_t *tvb, int offset, int len,
1824     proto_tree *tree)
1825 {
1826         guint8 octet;
1827
1828         if (len == 0)
1829                 return;
1830         octet = tvb_get_guint8(tvb, offset);
1831         proto_tree_add_text(tree, tvb, offset, 1,
1832             "Type of number: %s",
1833             val_to_str(octet & 0x70, q931_number_type_vals,
1834               "Unknown (0x%02X)"));
1835         proto_tree_add_text(tree, tvb, offset, 1,
1836             "Numbering plan: %s",
1837             val_to_str(octet & 0x0F, q931_numbering_plan_vals,
1838               "Unknown (0x%02X)"));
1839         offset += 1;
1840         len -= 1;
1841
1842         if (!(octet & Q931_IE_VL_EXTENSION)) {
1843                 if (len == 0)
1844                         return;
1845                 octet = tvb_get_guint8(tvb, offset);
1846                 proto_tree_add_text(tree, tvb, offset, 1,
1847                     "Presentation indicator: %s",
1848                     val_to_str(octet & 0x60, q931_presentation_indicator_vals,
1849                       "Unknown (0x%X)"));
1850                 proto_tree_add_text(tree, tvb, offset, 1,
1851                     "Screening indicator: %s",
1852                     val_to_str(octet & 0x03, q931_screening_indicator_vals,
1853                       "Unknown (0x%X)"));
1854                 offset += 1;
1855                 len -= 1;
1856         }
1857
1858         /*
1859          * XXX - only in a Redirecting number information element.
1860          */
1861         if (!(octet & Q931_IE_VL_EXTENSION)) {
1862                 if (len == 0)
1863                         return;
1864                 octet = tvb_get_guint8(tvb, offset);
1865                 proto_tree_add_text(tree, tvb, offset, 1,
1866                     "Reason for redirection: %s",
1867                     val_to_str(octet & 0x0F, q931_redirection_reason_vals,
1868                       "Unknown (0x%X)"));
1869                 offset += 1;
1870                 len -= 1;
1871         }
1872
1873         if (len == 0)
1874                 return;
1875         proto_tree_add_text(tree, tvb, offset, len, "Number: %s",
1876             tvb_format_text(tvb, offset, len));
1877 }
1878
1879 /*
1880  * Dissect a party subaddress information element.
1881  */
1882 static const value_string q931_subaddress_type_vals[] = {
1883         { 0x00, "X.213/ISO 8348 Add.2 NSAP" },
1884         { 0x20, "User-specified" },
1885         { 0,    NULL }
1886 };
1887
1888 static const value_string q931_odd_even_indicator_vals[] = {
1889         { 0x00, "Even number of address signals" },
1890         { 0x10, "Odd number of address signals" },
1891         { 0,    NULL }
1892 };
1893
1894 static void
1895 dissect_q931_party_subaddr_ie(tvbuff_t *tvb, int offset, int len,
1896     proto_tree *tree)
1897 {
1898         guint8 octet;
1899
1900         if (len == 0)
1901                 return;
1902         octet = tvb_get_guint8(tvb, offset);
1903         proto_tree_add_text(tree, tvb, offset, 1,
1904             "Type of subaddress: %s",
1905             val_to_str(octet & 0x70, q931_subaddress_type_vals,
1906               "Unknown (0x%02X)"));
1907         proto_tree_add_text(tree, tvb, offset, 1,
1908             "Odd/even indicator: %s",
1909             val_to_str(octet & 0x10, q931_odd_even_indicator_vals,
1910               NULL));
1911         offset += 1;
1912         len -= 1;
1913
1914         if (len == 0)
1915                 return;
1916         proto_tree_add_text(tree, tvb, offset, len, "Subaddress: %s",
1917             tvb_bytes_to_str(tvb, offset, len));
1918 }
1919
1920 /*
1921  * Dissect a Restart indicator information element.
1922  */
1923 static const value_string q931_restart_indicator_class_vals[] = {
1924         { 0x00, "Indicated channels" },
1925         { 0x06, "Single interface" },
1926         { 0x07, "All interfaces" },
1927         { 0,    NULL }
1928 };
1929
1930 static void
1931 dissect_q931_restart_indicator_ie(tvbuff_t *tvb, int offset, int len,
1932     proto_tree *tree)
1933 {
1934         if (len != 1) {
1935                 proto_tree_add_text(tree, tvb, offset, len,
1936                     "Restart indicator: length is %d, should be 1\n", len);
1937                 return;
1938         }
1939         proto_tree_add_text(tree, tvb, offset, 1,
1940             "Restart indicator: %s",
1941             val_to_str(tvb_get_guint8(tvb, offset) & 0x07,
1942               q931_restart_indicator_class_vals, "Unknown (0x%02X)"));
1943 }
1944
1945 /*
1946  * Dissect a High-layer compatibility information element.
1947  */
1948 #define Q931_AUDIOVISUAL        0x60
1949 static const value_string q931_high_layer_characteristics_vals[] = {
1950         { 0x01,             "Telephony" },
1951         { 0x04,             "F.182 Facsimile Group 2/3" },
1952         { 0x21,             "F.184 Facsimile Group 4 Class I" },
1953         { 0x24,             "F.230 Teletex, basic and mixed mode, and F.184 Facsimile Group 4, Classes II and III" },
1954         { 0x28,             "F.220 Teletex, basic and processable mode" },
1955         { 0x31,             "F.200 Teletex, basic mode" },
1956         { 0x32,             "F.300 and T.102 syntax-based Videotex" },
1957         { 0x33,             "F.300 and T.101 international Videotex interworking" },
1958         { 0x35,             "F.60 Telex" },
1959         { 0x38,             "X.400 Message Handling Systems" },
1960         { 0x41,             "X.200 OSI application" },
1961         { 0x42,             "FTAM application" },
1962         { 0x5E,             "Reserved for maintenance" },
1963         { 0x5F,             "Reserved for management" },
1964         { Q931_AUDIOVISUAL, "F.720/F.821 and F.731 Profile 1a videotelephony" },
1965         { 0x61,             "F.702 and F.731 Profile 1b videoconferencing" },
1966         { 0x62,             "F.702 and F.731 audiographic conferencing" },
1967         { 0,                NULL }
1968 };
1969
1970 static const value_string q931_audiovisual_characteristics_vals[] = {
1971         { 0x01, "Capability set of initial channel of H.221" },
1972         { 0x02, "Capability set of subsequent channel of H.221" },
1973         { 0x21, "Capability set of initial channel of an active 3.1kHz audio or speech call" },
1974         { 0x00, NULL }
1975 };
1976
1977 void
1978 dissect_q931_high_layer_compat_ie(tvbuff_t *tvb, int offset, int len,
1979     proto_tree *tree)
1980 {
1981         guint8 octet;
1982         guint8 coding_standard;
1983         guint8 characteristics;
1984
1985         if (len == 0)
1986                 return;
1987         octet = tvb_get_guint8(tvb, offset);
1988         coding_standard = octet & 0x60;
1989         proto_tree_add_text(tree, tvb, offset, 1,
1990             "Coding standard: %s",
1991             val_to_str(coding_standard, q931_coding_standard_vals, NULL));
1992         offset += 1;
1993         len -= 1;
1994         if (coding_standard != Q931_ITU_STANDARDIZED_CODING) {
1995                 /*
1996                  * We don't know how the call state is encoded,
1997                  * so just dump it as data and be done with it.
1998                  */
1999                 proto_tree_add_text(tree, tvb, offset,
2000                     len, "Data: %s",
2001                     tvb_bytes_to_str(tvb, offset, len));
2002                 return;
2003         }
2004
2005         if (len == 0)
2006                 return;
2007         octet = tvb_get_guint8(tvb, offset);
2008         characteristics = octet & 0x7F;
2009         proto_tree_add_text(tree, tvb, offset, 1,
2010             "High layer characteristics identification: %s",
2011             val_to_str(characteristics, q931_high_layer_characteristics_vals,
2012              "Unknown (0x%02X)"));
2013         offset += 1;
2014         len -= 1;
2015
2016         if (!(octet & Q931_IE_VL_EXTENSION)) {
2017                 if (len == 0)
2018                         return;
2019                 octet = tvb_get_guint8(tvb, offset);
2020                 if (characteristics == Q931_AUDIOVISUAL) {
2021                         proto_tree_add_text(tree, tvb, offset, 1,
2022                             "Extended audiovisual characteristics identification: %s",
2023                             val_to_str(octet & 0x7F,
2024                               q931_audiovisual_characteristics_vals,
2025                               "Unknown (0x%02X)"));
2026                 } else {
2027                         proto_tree_add_text(tree, tvb, offset, 1,
2028                             "Extended high layer characteristics identification: %s",
2029                             val_to_str(octet & 0x7F,
2030                               q931_high_layer_characteristics_vals,
2031                               "Unknown (0x%02X)"));
2032                 }
2033         }
2034 }
2035
2036
2037 /*
2038  * Dissect a User-user information element.
2039  */
2040 #define Q931_PROTOCOL_DISCRIMINATOR_IA5         0x04
2041 #define Q931_PROTOCOL_DISCRIMINATOR_ASN1        0x05
2042
2043 static const value_string q931_protocol_discriminator_vals[] = {
2044         { 0x00,                                 "User-specific protocol" },
2045         { 0x01,                                 "OSI high layer protocols" },
2046         { 0x02,                                 "X.244" },
2047         { Q931_PROTOCOL_DISCRIMINATOR_IA5,      "IA5 characters" },
2048         { Q931_PROTOCOL_DISCRIMINATOR_ASN1,     "X.208 and X.209 coded user information" },
2049         { 0x07,                                 "V.120 rate adaption" },
2050         { 0x08,                                 "Q.931/I.451 user-network call control messages" },
2051         { 0,                                    NULL }
2052 };
2053
2054 static void
2055 dissect_q931_user_user_ie(tvbuff_t *tvb, int offset, int len,
2056     proto_tree *tree)
2057 {
2058         guint8 octet;
2059
2060         if (len == 0)
2061                 return;
2062         octet = tvb_get_guint8(tvb, offset);
2063         proto_tree_add_text(tree, tvb, offset, 1,
2064             "Protocol discriminator: %s",
2065             val_to_str(octet, q931_protocol_discriminator_vals,
2066             "Unknown (0x%02x)"));
2067         offset += 1;
2068         len -= 1;
2069
2070         if (len == 0)
2071                 return;
2072         switch (octet) {
2073
2074         case Q931_PROTOCOL_DISCRIMINATOR_IA5:
2075                 proto_tree_add_text(tree, tvb, offset, len, "User information: %s",
2076                     tvb_format_text(tvb, offset, len));
2077                 break;
2078
2079         default:
2080                 proto_tree_add_text(tree, tvb, offset, len, "User information: %s",
2081                     tvb_bytes_to_str(tvb, offset, len));
2082                 break;
2083         }
2084 }
2085
2086 /*
2087  * Dissect information elements consisting of ASCII^H^H^H^H^HIA5 text.
2088  */
2089 static void
2090 dissect_q931_ia5_ie(tvbuff_t *tvb, int offset, int len, proto_tree *tree,
2091     char *label)
2092 {
2093         if (len != 0) {
2094                 proto_tree_add_text(tree, tvb, offset, len, "%s: %s", label,
2095                     tvb_format_text(tvb, offset, len));
2096         }
2097 }
2098
2099 static const value_string q931_codeset_vals[] = {
2100         { 0x00, "Q.931 information elements" },
2101         { 0x04, "Information elements for ISO/IEC use" },
2102         { 0x05, "Information elements for national use" },
2103         { 0x06, "Information elements specific to the local network" },
2104         { 0x07, "User-specific information elements" },
2105         { 0x00, NULL },
2106 };
2107
2108 static void
2109 dissect_q931_pdu(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree,
2110     gboolean is_tpkt)
2111 {
2112         int             offset = 0;
2113         proto_tree      *q931_tree = NULL;
2114         proto_item      *ti;
2115         proto_tree      *ie_tree = NULL;
2116         guint8          call_ref_len;
2117         guint8          call_ref[15];
2118         guint8          message_type;
2119         guint8          info_element;
2120         guint16         info_element_len;
2121         int             codeset;
2122         gboolean        non_locking_shift;
2123         tvbuff_t        *h225_tvb;
2124
2125         if (check_col(pinfo->cinfo, COL_PROTOCOL))
2126                 col_set_str(pinfo->cinfo, COL_PROTOCOL, "Q.931");
2127
2128         if (tree) {
2129                 ti = proto_tree_add_item(tree, proto_q931, tvb, offset, -1,
2130                     FALSE);
2131                 q931_tree = proto_item_add_subtree(ti, ett_q931);
2132
2133                 dissect_q931_protocol_discriminator(tvb, offset, q931_tree);
2134         }
2135         offset += 1;
2136         call_ref_len = tvb_get_guint8(tvb, offset) & 0xF;       /* XXX - do as a bit field? */
2137         if (q931_tree != NULL)
2138                 proto_tree_add_uint(q931_tree, hf_q931_call_ref_len, tvb, offset, 1, call_ref_len);
2139         offset += 1;
2140         if (call_ref_len != 0) {
2141                 tvb_memcpy(tvb, call_ref, offset, call_ref_len);
2142                 if (q931_tree != NULL) {
2143                         proto_tree_add_boolean(q931_tree, hf_q931_call_ref_flag,
2144                             tvb, offset, 1, (call_ref[0] & 0x80) != 0);
2145                         call_ref[0] &= 0x7F;
2146                         proto_tree_add_bytes(q931_tree, hf_q931_call_ref,
2147                             tvb, offset, call_ref_len, call_ref);
2148                 }
2149                 offset += call_ref_len;
2150         }
2151         message_type = tvb_get_guint8(tvb, offset);
2152         if (check_col(pinfo->cinfo, COL_INFO)) {
2153                 col_add_str(pinfo->cinfo, COL_INFO,
2154                     val_to_str(message_type, q931_message_type_vals,
2155                       "Unknown message type (0x%02X)"));
2156         }
2157         if (q931_tree != NULL)
2158                 proto_tree_add_uint(q931_tree, hf_q931_message_type, tvb, offset, 1, message_type);
2159         offset += 1;
2160
2161         /*
2162          * And now for the information elements....
2163          */
2164         codeset = 0;    /* start out in codeset 0 */
2165         non_locking_shift = TRUE;
2166         while (tvb_reported_length_remaining(tvb, offset) > 0) {
2167                 info_element = tvb_get_guint8(tvb, offset);
2168
2169                 /*
2170                  * Check for the single-octet IEs.
2171                  */
2172                 switch (info_element & Q931_IE_SO_IDENTIFIER_MASK) {
2173
2174                 case Q931_IE_SHIFT:
2175                         non_locking_shift =
2176                             !(info_element & Q931_IE_SHIFT_LOCKING);
2177                         codeset = info_element & Q931_IE_SHIFT_CODESET;
2178                         if (q931_tree != NULL) {
2179                                 proto_tree_add_text(q931_tree, tvb, offset, 1,
2180                                     "%s shift to codeset %u: %s",
2181                                     (non_locking_shift ? "Non-locking" : "Locking"),
2182                                     codeset,
2183                                     val_to_str(codeset, q931_codeset_vals,
2184                                       "Unknown (0x%02X)"));
2185                         }
2186                         offset += 1;
2187                         continue;
2188
2189                 case Q931_IE_MORE_DATA_OR_SEND_COMP:
2190                         switch (info_element) {
2191
2192                         case Q931_IE_MORE_DATA:
2193                                 if (q931_tree != NULL) {
2194                                         proto_tree_add_text(q931_tree, tvb, offset, 1,
2195                                             "More data");
2196                                 }
2197                                 break;
2198
2199                         case Q931_IE_SENDING_COMPLETE:
2200                                 if (q931_tree != NULL) {
2201                                         proto_tree_add_text(q931_tree, tvb, offset, 1,
2202                                             "Sending complete");
2203                                 }
2204                                 break;
2205
2206                         default:
2207                                 if (q931_tree != NULL) {
2208                                         proto_tree_add_text(q931_tree, tvb, offset, 1,
2209                                             "Unknown information element (0x%02X",
2210                                             info_element);
2211                                 }
2212                                 break;
2213                         }
2214                         offset += 1;
2215                         if (non_locking_shift)
2216                                 codeset = 0;
2217                         continue;
2218
2219                 case Q931_IE_CONGESTION_LEVEL:
2220                         if (q931_tree != NULL) {
2221                                 proto_tree_add_text(q931_tree, tvb, offset, 1,
2222                                     "Congestion level: %s",
2223                                     val_to_str(info_element & Q931_IE_SO_IE_MASK,
2224                                       q931_congestion_level_vals,
2225                                       "Unknown (0x%X)"));
2226                         }
2227                         offset += 1;
2228                         if (non_locking_shift)
2229                                 codeset = 0;
2230                         continue;
2231
2232                 case Q931_IE_REPEAT_INDICATOR:
2233                         if (q931_tree != NULL) {
2234                                 proto_tree_add_text(q931_tree, tvb, offset, 1,
2235                                     "Repeat indicator: %s",
2236                                     val_to_str(info_element & Q931_IE_SO_IE_MASK,
2237                                       q931_repeat_indication_vals,
2238                                       "Unknown (0x%X)"));
2239                         }
2240                         offset += 1;
2241                         if (non_locking_shift)
2242                                 codeset = 0;
2243                         continue;
2244
2245                 default:
2246                         break;
2247                 }
2248
2249                 /*
2250                  * Variable-length IE.
2251                  *
2252                  * According to page 18 from Recommendation H.225.0 :
2253                  * " Length of user-user contents contents
2254                  * - Shall be 2 octets instead of 1 (as in Figure 4-36/Q.931)"
2255                  *
2256                  * We assume that if this is Q.931-over-TPKT, it might
2257                  * be H.225 traffic, and check for the IE being a user-user
2258                  * IE with ASN.1 encoding of the user information.
2259                  */
2260                 if (is_tpkt && tvb_bytes_exist(tvb, offset, 4) &&
2261                     tvb_get_guint8(tvb, offset) == Q931_IE_USER_USER &&
2262                     tvb_get_guint8(tvb, offset + 3) == Q931_PROTOCOL_DISCRIMINATOR_ASN1)  {
2263                         info_element_len = tvb_get_ntohs(tvb, offset + 1);
2264                         if (q931_tree != NULL) {
2265                                 ti = proto_tree_add_text(q931_tree, tvb, offset,
2266                                     1+2+info_element_len, "%s",
2267                                     val_to_str(info_element,
2268                                       q931_info_element_vals,
2269                                       "Unknown information element (0x%02X)"));
2270                                 ie_tree = proto_item_add_subtree(ti,
2271                                     ett_q931_ie);
2272                                 proto_tree_add_text(ie_tree, tvb, offset, 1,
2273                                     "Information element: %s",
2274                                     val_to_str(info_element,
2275                                       q931_info_element_vals, "Unknown (0x%02X)"));
2276                                 proto_tree_add_text(ie_tree, tvb, offset + 1,
2277                                     2, "Length: %u", info_element_len);
2278                                 proto_tree_add_text(ie_tree, tvb, offset + 3,
2279                                     1, "Protocol discriminator: %s",
2280                                     val_to_str(tvb_get_guint8(tvb, offset + 3),
2281                                       q931_protocol_discriminator_vals,
2282                                       "Unknown (0x%02x)"));
2283                         }
2284
2285                         if (info_element_len > 1) {
2286                                 /*
2287                                  * Do we have a handle for the H.225
2288                                  * dissector?
2289                                  */
2290                                 if (h225_handle != NULL) {
2291                                         /*
2292                                          * Yes - call it, regardless of
2293                                          * whether we're building a
2294                                          * protocol tree or not.
2295                                          */
2296                                         h225_tvb = tvb_new_subset(tvb,
2297                                             offset + 4, info_element_len - 1,
2298                                             info_element_len - 1);
2299                                         call_dissector(h225_handle, h225_tvb,
2300                                             pinfo, tree);
2301                                 } else {
2302                                         /*
2303                                          * No - just show it as "User
2304                                          * information" (if "ie_tree" is
2305                                          * null, this won't add anything).
2306                                          */
2307                                         proto_tree_add_text(ie_tree, tvb,
2308                                             offset + 4, info_element_len - 1,
2309                                             "User information: %s",
2310                                             tvb_bytes_to_str(tvb, offset + 4,
2311                                               info_element_len - 1));
2312                                 }
2313                         }
2314                         offset += 1 + 2 + info_element_len;
2315                 } else {
2316                         info_element_len = tvb_get_guint8(tvb, offset + 1);
2317                         if (q931_tree != NULL) {
2318                                 ti = proto_tree_add_text(q931_tree, tvb, offset,
2319                                     1+1+info_element_len, "%s",
2320                                     val_to_str(info_element, q931_info_element_vals,
2321                                       "Unknown information element (0x%02X)"));
2322                                         ie_tree = proto_item_add_subtree(ti, ett_q931_ie);
2323                                 proto_tree_add_text(ie_tree, tvb, offset, 1,
2324                                     "Information element: %s",
2325                                     val_to_str(info_element, q931_info_element_vals,
2326                                       "Unknown (0x%02X)"));
2327                                 proto_tree_add_text(ie_tree, tvb, offset + 1, 1,
2328                                     "Length: %u", info_element_len);
2329
2330                                 switch (info_element) {
2331
2332                                 case Q931_IE_SEGMENTED_MESSAGE:
2333                                         dissect_q931_segmented_message_ie(tvb,
2334                                             offset + 2, info_element_len,
2335                                             ie_tree);
2336                                         break;
2337
2338                                 case Q931_IE_BEARER_CAPABILITY:
2339                                 case Q931_IE_LOW_LAYER_COMPAT:
2340                                         dissect_q931_bearer_capability_ie(tvb,
2341                                             offset + 2, info_element_len,
2342                                             ie_tree);
2343                                         break;
2344
2345                                 case Q931_IE_CAUSE:
2346                                         dissect_q931_cause_ie(tvb,
2347                                             offset + 2, info_element_len,
2348                                             ie_tree);
2349                                         break;
2350
2351                                 case Q931_IE_CALL_STATE:
2352                                         dissect_q931_call_state_ie(tvb,
2353                                             offset + 2, info_element_len,
2354                                             ie_tree);
2355                                         break;
2356
2357                                 case Q931_IE_CHANNEL_IDENTIFICATION:
2358                                         dissect_q931_channel_identification_ie(
2359                                             tvb, offset + 2, info_element_len,
2360                                             ie_tree);
2361                                         break;
2362
2363                                 case Q931_IE_PROGRESS_INDICATOR:
2364                                         dissect_q931_progress_indicator_ie(tvb,
2365                                             offset + 2, info_element_len,
2366                                             ie_tree);
2367                                         break;
2368
2369                                 case Q931_IE_NETWORK_SPECIFIC_FACIL:
2370                                 case Q931_IE_TRANSIT_NETWORK_SEL:
2371                                         dissect_q931_ns_facilities_ie(tvb,
2372                                             offset + 2, info_element_len,
2373                                             ie_tree);
2374                                         break;
2375
2376                                 case Q931_IE_NOTIFICATION_INDICATOR:
2377                                         dissect_q931_notification_indicator_ie(
2378                                             tvb, offset + 2, info_element_len,
2379                                             ie_tree);
2380                                         break;
2381
2382                                 case Q931_IE_DISPLAY:
2383                                         dissect_q931_ia5_ie(tvb, offset + 2,
2384                                             info_element_len, ie_tree,
2385                                             "Display information");
2386                                         break;
2387
2388                                 case Q931_IE_DATE_TIME:
2389                                         dissect_q931_date_time_ie(tvb,
2390                                             offset + 2, info_element_len,
2391                                             ie_tree);
2392                                         break;
2393
2394                                 case Q931_IE_KEYPAD_FACILITY:
2395                                         dissect_q931_ia5_ie(tvb, offset + 2,
2396                                             info_element_len, ie_tree,
2397                                             "Keypad facility");
2398                                         break;
2399
2400                                 case Q931_IE_SIGNAL:
2401                                         dissect_q931_signal_ie(tvb,
2402                                             offset + 2, info_element_len,
2403                                             ie_tree);
2404                                         break;
2405
2406                                 case Q931_IE_INFORMATION_RATE:
2407                                         dissect_q931_information_rate_ie(tvb,
2408                                             offset + 2, info_element_len,
2409                                             ie_tree);
2410                                         break;
2411
2412                                 case Q931_IE_E2E_TRANSIT_DELAY:
2413                                         dissect_q931_e2e_transit_delay_ie(tvb,
2414                                             offset + 2, info_element_len,
2415                                             ie_tree);
2416                                         break;
2417
2418                                 case Q931_IE_TD_SELECTION_AND_INT:
2419                                         dissect_q931_td_selection_and_int_ie(
2420                                             tvb, offset + 2, info_element_len,
2421                                             ie_tree);
2422                                         break;
2423
2424                                 case Q931_IE_PL_BINARY_PARAMETERS:
2425                                         dissect_q931_pl_binary_parameters_ie(
2426                                             tvb, offset + 2, info_element_len,
2427                                             ie_tree);
2428                                         break;
2429
2430                                 case Q931_IE_PL_WINDOW_SIZE:
2431                                         dissect_q931_pl_window_size_ie(tvb,
2432                                             offset + 2, info_element_len,
2433                                             ie_tree);
2434                                         break;
2435
2436                                 case Q931_IE_PACKET_SIZE:
2437                                         dissect_q931_packet_size_ie(tvb,
2438                                             offset + 2, info_element_len,
2439                                             ie_tree);
2440                                         break;
2441
2442                                 case Q931_IE_CUG:
2443                                         dissect_q931_cug_ie(tvb,
2444                                             offset + 2, info_element_len,
2445                                             ie_tree);
2446                                         break;
2447
2448                                 case Q931_IE_REVERSE_CHARGE_IND:
2449                                         dissect_q931_reverse_charge_ind_ie(tvb,
2450                                             offset + 2, info_element_len,
2451                                             ie_tree);
2452                                         break;
2453
2454                                 case Q931_IE_CALLING_PARTY_NUMBER:
2455                                 case Q931_IE_CONNECTED_NUMBER_DEFAULT:
2456                                 case Q931_IE_CALLED_PARTY_NUMBER:
2457                                 case Q931_IE_REDIRECTING_NUMBER:
2458                                         dissect_q931_number_ie(tvb,
2459                                             offset + 2, info_element_len,
2460                                             ie_tree);
2461                                         break;
2462
2463                                 case Q931_IE_CALLING_PARTY_SUBADDR:
2464                                 case Q931_IE_CALLED_PARTY_SUBADDR:
2465                                         dissect_q931_party_subaddr_ie(tvb,
2466                                             offset + 2, info_element_len,
2467                                             ie_tree);
2468                                         break;
2469
2470                                 case Q931_IE_RESTART_INDICATOR:
2471                                         dissect_q931_restart_indicator_ie(tvb,
2472                                             offset + 2, info_element_len,
2473                                             ie_tree);
2474                                         break;
2475
2476                                 case Q931_IE_HIGH_LAYER_COMPAT:
2477                                         dissect_q931_high_layer_compat_ie(tvb,
2478                                             offset + 2, info_element_len,
2479                                             ie_tree);
2480                                         break;
2481
2482                                 case Q931_IE_USER_USER:
2483                                         dissect_q931_user_user_ie(tvb,
2484                                             offset + 2, info_element_len,
2485                                             ie_tree);
2486                                         break;
2487
2488                                 default:
2489                                         proto_tree_add_text(ie_tree, tvb,
2490                                             offset + 2, info_element_len,
2491                                             "Data: %s",
2492                                             bytes_to_str(
2493                                               tvb_get_ptr(tvb, offset + 2,
2494                                                   info_element_len),
2495                                                   info_element_len));
2496                                         break;
2497                                 }
2498                         }
2499                         offset += 1 + 1 + info_element_len;
2500                 }
2501                 if (non_locking_shift)
2502                         codeset = 0;
2503         }
2504 }
2505
2506 /*
2507  * Q.931-over-TPKT-over-TCP.
2508  */
2509 static gboolean
2510 dissect_q931_tpkt(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
2511 {
2512         int lv_tpkt_len;
2513
2514         /*
2515          * Check whether this looks like a TPKT-encapsulated
2516          * Q.931 packet.
2517          *
2518          * The minimum length of a Q.931 message is 3:
2519          * 1 byte for the protocol discriminator,
2520          * 1 for the call_reference length,
2521          * and one for the message type.
2522          */
2523         lv_tpkt_len = is_tpkt(tvb, 3);
2524         if (lv_tpkt_len == -1) {
2525                 /*
2526                  * It's not a TPKT packet; reject it.
2527                  */
2528                 return FALSE;
2529         }
2530
2531         /*
2532          * If this segment is *exactly* the length of a TPKT header,
2533          * we assume that, as it looks like a TPKT header, it
2534          * is one, and that the code put a TPKT header in one
2535          * segment and the rest of the PDU in another.
2536          */
2537         if (tvb_length(tvb) == 4) {
2538                 /*
2539                  * It is - call the "dissect TPKT over a TCP stream"
2540                  * routine.
2541                  */
2542                 dissect_tpkt_encap(tvb, pinfo, tree, q931_desegment,
2543                     q931_tpkt_pdu_handle);
2544                 return TRUE;
2545         }
2546
2547         /*
2548          * Well, we have more data than just the TPKT header;
2549          * check whether it looks like the beginning of a
2550          * Q.931 message.
2551          *
2552          * The minimum length of a Q.931 message is 3, as per the
2553          * above.
2554          *
2555          * Check that we have that many bytes past the TPKT header in
2556          * the tvbuff; we already know that the TPKT header says we
2557          * have that many bytes (as we passed 3 as the "min_len" argument
2558          * to "is_tpkt()").
2559          */
2560         if (!tvb_bytes_exist(tvb, 4, 3))
2561                 return FALSE;
2562
2563         /* Check the protocol discriminator */
2564         if (tvb_get_guint8(tvb, 4) != NLPID_Q_931) {
2565                 /* Doesn't look like Q.931 inside TPKT */
2566                 return FALSE;
2567         }
2568
2569         /*
2570          * OK, it looks like Q.931-over-TPKT.
2571          * Call the "dissect TPKT over a TCP stream" routine.
2572          */
2573         dissect_tpkt_encap(tvb, pinfo, tree, q931_desegment,
2574             q931_tpkt_pdu_handle);
2575
2576         return TRUE;
2577 }
2578
2579 static void
2580 dissect_q931_tpkt_pdu(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
2581 {
2582         dissect_q931_pdu(tvb, pinfo, tree, TRUE);
2583 }
2584
2585 static void
2586 dissect_q931(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
2587 {
2588         dissect_q931_pdu(tvb, pinfo, tree, FALSE);
2589 }
2590
2591 void
2592 proto_register_q931(void)
2593 {
2594         static hf_register_info hf[] = {
2595                 { &hf_q931_discriminator,
2596                   { "Protocol discriminator", "q931.disc", FT_UINT8, BASE_HEX, NULL, 0x0,
2597                         "", HFILL }},
2598
2599                 { &hf_q931_call_ref_len,
2600                   { "Call reference value length", "q931.call_ref_len", FT_UINT8, BASE_DEC, NULL, 0x0,
2601                         "", HFILL }},
2602
2603                 { &hf_q931_call_ref_flag,
2604                   { "Call reference flag", "q931.call_ref_flag", FT_BOOLEAN, BASE_NONE, TFS(&tfs_call_ref_flag), 0x0,
2605                         "", HFILL }},
2606
2607                 { &hf_q931_call_ref,
2608                   { "Call reference value", "q931.call_ref", FT_BYTES, BASE_HEX, NULL, 0x0,
2609                         "", HFILL }},
2610
2611                 { &hf_q931_message_type,
2612                   { "Message type", "q931.message_type", FT_UINT8, BASE_HEX, VALS(q931_message_type_vals), 0x0,
2613                         "", HFILL }},
2614         };
2615         static gint *ett[] = {
2616                 &ett_q931,
2617                 &ett_q931_ie,
2618         };
2619         module_t *q931_module;
2620
2621         proto_q931 = proto_register_protocol("Q.931", "Q.931", "q931");
2622         proto_register_field_array (proto_q931, hf, array_length(hf));
2623         proto_register_subtree_array(ett, array_length(ett));
2624
2625         register_dissector("q931", dissect_q931, proto_q931);
2626         q931_tpkt_pdu_handle = create_dissector_handle(dissect_q931_tpkt_pdu,
2627             proto_q931);
2628
2629         q931_module = prefs_register_protocol(proto_q931, NULL);
2630         prefs_register_bool_preference(q931_module, "desegment_h323_messages",
2631             "Desegment all Q.931 messages spanning multiple TCP segments",
2632             "Whether the Q.931 dissector should desegment all messages spanning multiple TCP segments",
2633             &q931_desegment);
2634 }
2635
2636 void
2637 proto_reg_handoff_q931(void)
2638 {
2639         /*
2640          * Attempt to get a handle for the H.225 dissector.
2641          * If we can't, the handle we get is null, and we'll just
2642          * dissect putatively-H.255 Call Signaling stuff as User
2643          * Information.
2644          */
2645         h225_handle = find_dissector("h225");
2646
2647         /*
2648          * For H.323.
2649          */
2650         heur_dissector_add("tcp", dissect_q931_tpkt, proto_q931);
2651 }