epan/dissectors/packet-fbzero.c

   1 /* packet-fbzero.c
   2  * Routines for Zero Protocol dissection
   3  * Copyright 2016-2017, Alexis La Goutte <alexis.lagoutte at gmail dot com>
   4  *
   5  * Wireshark - Network traffic analyzer
   6  * By Gerald Combs <gerald@wireshark.org>
   7  * Copyright 1998 Gerald Combs
   8  *
   9  * SPDX-License-Identifier: GPL-2.0-or-later
  10  */
  11
  12 /*
  13  * Zero Protocol coming from Facebook and used the same framing like QUIC
  14  * (tag-map value) but based on TCP
  15  *
  16  * See
  17  *
  18  *    https://engineering.fb.com/networking-traffic/building-zero-protocol-for-fast-secure-mobile-connections/
  19  *
  20  * for some (not much!) information on it.
  21  *
  22  * It was reverse engineered based off of QUIC dissector functionality
  23  */
  24 #include "config.h"
  25
  26 #include <epan/packet.h>
  27 #include <epan/tfs.h>
  28 #include <epan/expert.h>
  29 #include <epan/conversation.h>
  30
  31 void proto_register_fb_zero(void);
  32 void proto_reg_handoff_fb_zero(void);
  33
  34 static int proto_fb_zero;
  35
  36 static dissector_handle_t fb_zero_handle;
  37
  38 static int hf_fb_zero_puflags;
  39 static int hf_fb_zero_puflags_vrsn;
  40 static int hf_fb_zero_puflags_unknown;
  41 static int hf_fb_zero_version;
  42 static int hf_fb_zero_length;
  43 static int hf_fb_zero_tag;
  44 static int hf_fb_zero_tags;
  45 static int hf_fb_zero_tag_number;
  46 static int hf_fb_zero_tag_value;
  47 static int hf_fb_zero_tag_type;
  48 static int hf_fb_zero_tag_offset_end;
  49 static int hf_fb_zero_tag_length;
  50 static int hf_fb_zero_tag_sni;
  51 static int hf_fb_zero_tag_vers;
  52 static int hf_fb_zero_tag_sno;
  53 static int hf_fb_zero_tag_aead;
  54 static int hf_fb_zero_tag_scid;
  55 static int hf_fb_zero_tag_time;
  56 static int hf_fb_zero_tag_alpn;
  57 static int hf_fb_zero_tag_pubs;
  58 static int hf_fb_zero_tag_kexs;
  59 static int hf_fb_zero_tag_nonc;
  60
  61 static int hf_fb_zero_tag_unknown;
  62
  63 static int hf_fb_zero_padding;
  64 static int hf_fb_zero_payload;
  65 static int hf_fb_zero_unknown;
  66
  67 static int ett_fb_zero;
  68 static int ett_fb_zero_puflags;
  69 static int ett_fb_zero_prflags;
  70 static int ett_fb_zero_ft;
  71 static int ett_fb_zero_ftflags;
  72 static int ett_fb_zero_tag_value;
  73
  74 static expert_field ei_fb_zero_tag_undecoded;
  75 static expert_field ei_fb_zero_tag_offset_end_invalid;
  76 static expert_field ei_fb_zero_length_invalid;
  77
  78 #define FBZERO_MIN_LENGTH 3
  79
  80 #define VERSION_QTV 0x515456
  81
  82 /**************************************************************************/
  83 /*                      Public Flags                                      */
  84 /**************************************************************************/
  85 #define PUFLAGS_VRSN    0x01
  86 #define PUFLAGS_UNKN    0xFE
  87
  88 /**************************************************************************/
  89 /*                      Message tag                                       */
  90 /**************************************************************************/
  91
  92 #define MTAG_CHLO 0x43484C4F
  93 #define MTAG_SNOM 0x534E4F4D
  94 #define MTAG_SHLO 0x53484C4F
  95 #define MTAG_REJ  0x52454A00
  96 #define MTAG_PRST 0x50525354
  97
  98 static const value_string message_tag_vals[] = {
  99     { MTAG_CHLO, "Client Hello" },
 100     { MTAG_SNOM, "Server NOM??" },
 101     { MTAG_SHLO, "Server Hello" },
 102     { MTAG_REJ, "Rejection" },
 103     { MTAG_PRST, "Public Reset" },
 104     { 0, NULL }
 105 };
 106
 107 /**************************************************************************/
 108 /*                      Tag                                               */
 109 /**************************************************************************/
 110
 111 #define TAG_SNI  0x534E4900
 112 #define TAG_VERS 0x56455253
 113 #define TAG_SNO  0x534E4F00
 114 #define TAG_AEAD 0x41454144
 115 #define TAG_SCID 0x53434944
 116 #define TAG_TIME 0x54494d45
 117 #define TAG_ALPN 0x414C504E
 118 #define TAG_PUBS 0x50554253
 119 #define TAG_KEXS 0x4B455853
 120 #define TAG_NONC 0x4E4F4E43
 121
 122 static const value_string tag_vals[] = {
 123     { TAG_SNI, "Server Name Indication" },
 124     { TAG_VERS, "Version" },
 125     { TAG_SNO, "Server nonce" },
 126     { TAG_AEAD, "Authenticated encryption algorithms" },
 127     { TAG_SCID, "Server config ID" },
 128     { TAG_TIME, "Time" },
 129     { TAG_ALPN, "ALPN" },
 130     { TAG_PUBS, "Public value" },
 131     { TAG_KEXS, "Key exchange algorithms" },
 132     { TAG_NONC, "Client Nonce" },
 133     { 0, NULL }
 134 };
 135
 136
 137 /**************************************************************************/
 138 /*                      AEAD Tag                                          */
 139 /**************************************************************************/
 140
 141 #define AEAD_AESG  0x41455347
 142 #define AEAD_S20P  0x53323050
 143 #define AEAD_CC12  0x43433132
 144
 145 static const value_string tag_aead_vals[] = {
 146     { AEAD_AESG, "AES-GCM with a 12-byte tag and IV" },
 147     { AEAD_S20P, "Salsa20 with Poly1305" },
 148     { AEAD_CC12, "ChaCha12 with Poly1305" },
 149     { 0, NULL }
 150 };
 151
 152 /**************************************************************************/
 153 /*                      KEXS Tag                                          */
 154 /**************************************************************************/
 155
 156 #define KEXS_C255  0x43323535
 157 #define KEXS_P256  0x50323536
 158
 159 static const value_string tag_kexs_vals[] = {
 160     { KEXS_C255, "Curve25519" },
 161     { KEXS_P256, "P-256" },
 162     { 0, NULL }
 163 };
 164
 165
 166 static uint32_t
 167 dissect_fb_zero_tag(tvbuff_t *tvb, packet_info *pinfo, proto_tree *fb_zero_tree, unsigned offset, uint32_t tag_number){
 168     uint32_t tag_offset_start = offset + tag_number*4*2;
 169     uint32_t tag_offset = 0, total_tag_len = 0;
 170     int32_t tag_len = 0;
 171     bool tag_offset_valid = true;
 172
 173     while(tag_number){
 174         proto_tree *tag_tree;
 175         proto_item *ti_tag, *ti_type, *ti_offset_len, *ti_len;
 176         uint32_t offset_end, tag;
 177         const uint8_t* tag_str;
 178
 179         /*
 180          * This item covers the tag type and end offset; the tag values
 181          * are in a separate region following all the type/end offset
 182          * pairs.
 183          */
 184         ti_tag = proto_tree_add_item(fb_zero_tree, hf_fb_zero_tags, tvb, offset, 4*2, ENC_NA);
 185         tag_tree = proto_item_add_subtree(ti_tag, ett_fb_zero_tag_value);
 186         ti_type = proto_tree_add_item_ret_string(tag_tree, hf_fb_zero_tag_type, tvb, offset, 4, ENC_ASCII|ENC_NA, pinfo->pool, &tag_str);
 187         tag = tvb_get_ntohl(tvb, offset);
 188         proto_item_append_text(ti_type, " (%s)", val_to_str_const(tag, tag_vals, "Unknown"));
 189         proto_item_append_text(ti_tag, ": %s (%s)", tag_str, val_to_str_const(tag, tag_vals, "Unknown"));
 190         offset += 4;
 191
 192         ti_offset_len = proto_tree_add_item_ret_uint(tag_tree, hf_fb_zero_tag_offset_end, tvb, offset, 4, ENC_LITTLE_ENDIAN, &offset_end);
 193         if(offset_end < tag_offset){
 194             expert_add_info_format(pinfo, ti_offset_len, &ei_fb_zero_tag_offset_end_invalid,
 195                                    "Invalid tag end offset %u < %u",
 196                                    offset_end, tag_offset);
 197             /*
 198              * We can continue to show the tag type, end offset, and length,
 199              * but we can no longer show the values, or subsequent length
 200              * values, as the end offset in the tag value region is bogus.
 201              */
 202             tag_offset_valid = false;
 203         } else {
 204             tag_len = offset_end - tag_offset;
 205             if(!tvb_bytes_exist(tvb, tag_offset_start + tag_offset, tag_len)){
 206                 expert_add_info_format(pinfo, ti_offset_len, &ei_fb_zero_tag_offset_end_invalid,
 207                                        "Invalid tag end offset %u past end of packet",
 208                                        offset_end);
 209                 /*
 210                  * We can continue to show the tag type, end offset,
 211                  * and length, but we can no longer show the values,
 212                  * as the end offset in the tag value region is bogus.
 213                  *
 214                  * We don't just throw an exception here, because we
 215                  * want to show all the tag type and end offset values.
 216                  */
 217                 tag_offset_valid = false;
 218             }
 219             total_tag_len += tag_len;
 220             ti_len = proto_tree_add_uint(tag_tree, hf_fb_zero_tag_length, tvb, offset, 4, tag_len);
 221             proto_item_append_text(ti_tag, " (l=%u)", tag_len);
 222             proto_item_set_generated(ti_len);
 223         }
 224         offset += 4;
 225
 226         if(tag_offset_valid){
 227             proto_tree_add_item(tag_tree, hf_fb_zero_tag_value, tvb, tag_offset_start + tag_offset, tag_len, ENC_NA);
 228         }
 229
 230         switch(tag){
 231             case TAG_SNI:
 232                 if(tag_offset_valid){
 233                     proto_tree_add_item_ret_string(tag_tree, hf_fb_zero_tag_sni, tvb, tag_offset_start + tag_offset, tag_len, ENC_ASCII|ENC_NA, pinfo->pool, &tag_str);
 234                     proto_item_append_text(ti_tag, ": %s", tag_str);
 235                     tag_offset += tag_len;
 236                 }
 237                 break;
 238             case TAG_VERS:
 239                 if(tag_offset_valid){
 240                     if(tag_len != 4){
 241                         expert_add_info_format(pinfo, fb_zero_tree, &ei_fb_zero_length_invalid,
 242                                                "Invalid tag length: %u, should be 4", tag_len);
 243                         tag_offset += tag_len;
 244                         break;
 245                     }
 246                     proto_tree_add_item_ret_string(tag_tree, hf_fb_zero_tag_vers, tvb, tag_offset_start + tag_offset, 4, ENC_ASCII|ENC_NA, pinfo->pool, &tag_str);
 247                     proto_item_append_text(ti_tag, ": %s", tag_str);
 248                     tag_offset += 4;
 249                 }
 250             break;
 251             case TAG_SNO:
 252                 if(tag_offset_valid){
 253                     proto_tree_add_item(tag_tree, hf_fb_zero_tag_sno, tvb, tag_offset_start + tag_offset, tag_len, ENC_NA);
 254                     tag_offset += tag_len;
 255                 }
 256             break;
 257             case TAG_AEAD:
 258                 if(tag_offset_valid){
 259                     while(offset_end - tag_offset >= 4){
 260                         proto_tree *ti_aead;
 261                         ti_aead = proto_tree_add_item(tag_tree, hf_fb_zero_tag_aead, tvb, tag_offset_start + tag_offset, 4, ENC_ASCII);
 262                         proto_item_append_text(ti_aead, " (%s)", val_to_str_const(tvb_get_ntohl(tvb, tag_offset_start + tag_offset), tag_aead_vals, "Unknown"));
 263                         proto_item_append_text(ti_tag, ", %s", val_to_str_const(tvb_get_ntohl(tvb, tag_offset_start + tag_offset), tag_aead_vals, "Unknown"));
 264                         tag_offset += 4;
 265                     }
 266                     if(offset_end - tag_offset > 0){
 267                         expert_add_info_format(pinfo, fb_zero_tree, &ei_fb_zero_length_invalid,
 268                                                "Invalid tag length: %u, should be a multiple of 4", tag_len);
 269                         tag_offset = offset_end;
 270                     }
 271                 }
 272             break;
 273             case TAG_SCID:
 274                 if(tag_offset_valid){
 275                     proto_tree_add_item(tag_tree, hf_fb_zero_tag_scid, tvb, tag_offset_start + tag_offset, tag_len, ENC_NA);
 276                     tag_offset += tag_len;
 277                 }
 278             break;
 279             case TAG_TIME:
 280                 if(tag_offset_valid){
 281                     if(tag_len != 4){
 282                         expert_add_info_format(pinfo, fb_zero_tree, &ei_fb_zero_length_invalid,
 283                                                "Invalid tag length: %u, should be 4", tag_len);
 284                         tag_offset += tag_len;
 285                         break;
 286                     }
 287                     proto_tree_add_item(tag_tree, hf_fb_zero_tag_time, tvb, tag_offset_start + tag_offset, 4, ENC_LITTLE_ENDIAN);
 288                     proto_item_append_text(ti_tag, ": %u", tvb_get_letohl(tvb, tag_offset_start + tag_offset));
 289                     tag_offset += 4;
 290                 }
 291             break;
 292             case TAG_ALPN:
 293                 if(tag_offset_valid){
 294                     if(tag_len != 4){
 295                         expert_add_info_format(pinfo, fb_zero_tree, &ei_fb_zero_length_invalid,
 296                                                "Invalid tag length: %u, should be 4", tag_len);
 297                         tag_offset += tag_len;
 298                         break;
 299                     }
 300                     proto_tree_add_item_ret_string(tag_tree, hf_fb_zero_tag_alpn, tvb, tag_offset_start + tag_offset, 4, ENC_ASCII|ENC_NA, pinfo->pool, &tag_str);
 301                     proto_item_append_text(ti_tag, ": %s", tag_str);
 302                     tag_offset += 4;
 303                 }
 304             break;
 305             case TAG_PUBS:
 306                 if(tag_offset_valid){
 307                     /*TODO FIX: 24 Length + Pubs key?.. ! */
 308                     if(tag_len < 2){
 309                         expert_add_info_format(pinfo, fb_zero_tree, &ei_fb_zero_length_invalid,
 310                                                "Invalid tag length: %u, should be >= 2", tag_len);
 311                         tag_offset += tag_len;
 312                         break;
 313                     }
 314                     proto_tree_add_item(tag_tree, hf_fb_zero_tag_pubs, tvb, tag_offset_start + tag_offset, 2, ENC_LITTLE_ENDIAN);
 315                     tag_offset += 2;
 316                     while(offset_end - tag_offset >= 3){
 317                         proto_tree_add_item(tag_tree, hf_fb_zero_tag_pubs, tvb, tag_offset_start + tag_offset, 3, ENC_LITTLE_ENDIAN);
 318                         tag_offset += 3;
 319                     }
 320                     if(offset_end - tag_offset > 0){
 321                         expert_add_info_format(pinfo, fb_zero_tree, &ei_fb_zero_length_invalid,
 322                                                "Invalid tag length: %u, should be a multiple of 3", tag_len);
 323                         tag_offset = offset_end;
 324                     }
 325                 }
 326             break;
 327             case TAG_KEXS:
 328                 if(tag_offset_valid){
 329                     while(offset_end - tag_offset >= 4){
 330                         proto_tree *ti_kexs;
 331                         ti_kexs = proto_tree_add_item(tag_tree, hf_fb_zero_tag_kexs, tvb, tag_offset_start + tag_offset, 4, ENC_ASCII);
 332                         proto_item_append_text(ti_kexs, " (%s)", val_to_str_const(tvb_get_ntohl(tvb, tag_offset_start + tag_offset), tag_kexs_vals, "Unknown"));
 333                         proto_item_append_text(ti_tag, ", %s", val_to_str_const(tvb_get_ntohl(tvb, tag_offset_start + tag_offset), tag_kexs_vals, "Unknown"));
 334                         tag_offset += 4;
 335                     }
 336                     if(offset_end - tag_offset > 0){
 337                         expert_add_info_format(pinfo, fb_zero_tree, &ei_fb_zero_length_invalid,
 338                                                "Invalid tag length: %u, should be a multiple of 4", tag_len);
 339                         tag_offset = offset_end;
 340                     }
 341                 }
 342             break;
 343             case TAG_NONC:
 344                 if(tag_offset_valid){
 345                     /*TODO: Enhance display: 32 bytes consisting of 4 bytes of timestamp (big-endian, UNIX epoch seconds), 8 bytes of server orbit and 20 bytes of random data. */
 346                     if(tag_len != 32){
 347                         expert_add_info_format(pinfo, fb_zero_tree, &ei_fb_zero_length_invalid,
 348                                                "Invalid tag length: %u, should be 32", tag_len);
 349                         tag_offset += tag_len;
 350                         break;
 351                     }
 352                     proto_tree_add_item(tag_tree, hf_fb_zero_tag_nonc, tvb, tag_offset_start + tag_offset, 32, ENC_NA);
 353                     tag_offset += 32;
 354                 }
 355             break;
 356             default:
 357                 expert_add_info_format(pinfo, ti_tag, &ei_fb_zero_tag_undecoded,
 358                                  "Dissector for FB Zero Tag"
 359                                  " %s (%s) code not implemented, Contact"
 360                                  " Wireshark developers if you want this supported",
 361                                  tvb_get_string_enc(pinfo->pool, tvb, offset-8, 4, ENC_ASCII|ENC_NA), val_to_str_const(tag, tag_vals, "Unknown"));
 362                 if(tag_offset_valid){
 363                     proto_tree_add_item(tag_tree, hf_fb_zero_tag_unknown, tvb, tag_offset_start + tag_offset, tag_len, ENC_NA);
 364                     tag_offset += tag_len;
 365                 }
 366                 break;
 367         }
 368
 369         tag_number--;
 370     }
 371
 372     /* XXX - can this still occur? */
 373     if (offset + total_tag_len <= offset) {
 374         expert_add_info_format(pinfo, fb_zero_tree, &ei_fb_zero_length_invalid,
 375                          "Invalid total tag length: %u", total_tag_len);
 376         return offset + tvb_reported_length_remaining(tvb, offset);
 377     }
 378     return offset + total_tag_len;
 379
 380 }
 381
 382
 383 static int
 384 dissect_fb_zero_unencrypt(tvbuff_t *tvb, packet_info *pinfo, proto_tree *fb_zero_tree, unsigned offset, uint8_t len_pkn _U_){
 385
 386     while(tvb_reported_length_remaining(tvb, offset) > 0){
 387         proto_item *ti;
 388         uint32_t message_tag, tag_number, length;
 389         const uint8_t* message_tag_str;
 390         proto_tree_add_item(fb_zero_tree, hf_fb_zero_unknown, tvb, offset, 1, ENC_NA);
 391         offset += 1;
 392
 393         /*
 394          * XXX: in theory, a tagged message could be split between
 395          * TCP segments - even the *header containing the length*
 396          * could be split - but, from the sequence described in the
 397          * Facebook blog post, that's probably unlikely in practice.
 398          */
 399         proto_tree_add_item_ret_uint(fb_zero_tree, hf_fb_zero_length, tvb, offset, 4, ENC_LITTLE_ENDIAN, &length);
 400         offset += 4;
 401
 402         message_tag = tvb_get_ntohl(tvb, offset);
 403         /* check if it is a known message_tag (CHLO, SNOM...) */
 404         if(try_val_to_str(message_tag, message_tag_vals)){
 405             ti = proto_tree_add_item_ret_string(fb_zero_tree, hf_fb_zero_tag, tvb, offset, 4, ENC_ASCII|ENC_NA, pinfo->pool, &message_tag_str);
 406
 407             proto_item_append_text(ti, ", Type: %s (%s)", message_tag_str,
 408                                    val_to_str_const(message_tag, message_tag_vals, "Unknown Tag"));
 409             col_set_str(pinfo->cinfo, COL_INFO, val_to_str_const(message_tag, message_tag_vals, "Unknown"));
 410             offset += 4;
 411
 412             proto_tree_add_item(fb_zero_tree, hf_fb_zero_tag_number, tvb, offset, 2, ENC_LITTLE_ENDIAN);
 413             tag_number = tvb_get_letohs(tvb, offset);
 414             offset += 2;
 415
 416             proto_tree_add_item(fb_zero_tree, hf_fb_zero_padding, tvb, offset, 2, ENC_NA);
 417             offset += 2;
 418
 419             offset = dissect_fb_zero_tag(tvb, pinfo, fb_zero_tree, offset, tag_number);
 420         } else {
 421             proto_tree_add_item(fb_zero_tree, hf_fb_zero_unknown, tvb, offset, length, ENC_NA);
 422             offset += length;
 423         }
 424     }
 425
 426     return offset;
 427
 428 }
 429
 430 static int
 431 dissect_fb_zero_common(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree,
 432         void *data _U_)
 433 {
 434     proto_item *ti, *ti_puflags;
 435     proto_tree *fb_zero_tree, *puflags_tree;
 436     unsigned offset = 0;
 437     uint8_t puflags;
 438     uint32_t message_tag, version;
 439
 440     if (tvb_captured_length(tvb) < FBZERO_MIN_LENGTH)
 441         return 0;
 442
 443
 444     col_set_str(pinfo->cinfo, COL_PROTOCOL, "FB_ZERO");
 445
 446     ti = proto_tree_add_item(tree, proto_fb_zero, tvb, 0, -1, ENC_NA);
 447     fb_zero_tree = proto_item_add_subtree(ti, ett_fb_zero);
 448
 449     /* Public Flags */
 450     ti_puflags = proto_tree_add_item(fb_zero_tree, hf_fb_zero_puflags, tvb, offset, 1, ENC_LITTLE_ENDIAN);
 451     puflags_tree = proto_item_add_subtree(ti_puflags, ett_fb_zero_puflags);
 452     proto_tree_add_item(puflags_tree, hf_fb_zero_puflags_vrsn, tvb, offset, 1, ENC_NA);
 453     proto_tree_add_item(puflags_tree, hf_fb_zero_puflags_unknown, tvb, offset, 1, ENC_LITTLE_ENDIAN);
 454     puflags = tvb_get_uint8(tvb, offset);
 455     offset += 1;
 456
 457     if(puflags & PUFLAGS_VRSN){
 458         version = tvb_get_ntoh24(tvb, offset);
 459         if(version == VERSION_QTV){
 460             proto_tree_add_item(fb_zero_tree, hf_fb_zero_version, tvb, offset, 3, ENC_ASCII);
 461             offset += 3;
 462         }
 463     }
 464
 465     /* Unencrypt Message (Handshake or Connection Close...) */
 466     message_tag = tvb_get_ntohl(tvb, offset+5);
 467     if (message_tag == MTAG_CHLO || message_tag == MTAG_SNOM) {
 468         offset = dissect_fb_zero_unencrypt(tvb, pinfo, fb_zero_tree, offset, 1);
 469
 470     }else {     /* Payload... (encrypted... TODO FIX !) */
 471         col_set_str(pinfo->cinfo, COL_INFO, "Payload (Encrypted)");
 472         proto_tree_add_item(fb_zero_tree, hf_fb_zero_payload, tvb, offset, -1, ENC_NA);
 473     }
 474     return offset;
 475 }
 476
 477
 478 static int
 479 dissect_fb_zero(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree,
 480               void *data _U_)
 481 {
 482     return dissect_fb_zero_common(tvb, pinfo, tree, NULL);
 483 }
 484
 485 static bool dissect_fb_zero_heur(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data)
 486 {
 487     conversation_t *conversation = NULL;
 488     int offset = 0;
 489     uint32_t version, length, message_tag;
 490     /* Verify packet size (Flag (1 byte) + Version (3bytes) + Flag (1 byte) + length (4 bytes) + Tag (4 bytes)) */
 491     if (tvb_captured_length(tvb) < 13)
 492     {
 493         return false;
 494     }
 495
 496     /* Flag */
 497     offset += 1;
 498
 499     /* Version */
 500     version = tvb_get_ntoh24(tvb, offset);
 501     offset += 3;
 502
 503     /* Flag */
 504     offset += 1;
 505
 506     /* length */
 507     length = tvb_get_letohl(tvb, offset);
 508     offset += 4;
 509
 510     /* (message) tag */
 511     message_tag = tvb_get_ntohl(tvb, offset);
 512
 513     if (version == VERSION_QTV && length <= tvb_reported_length(tvb) && (message_tag == MTAG_CHLO || message_tag == MTAG_SNOM)) {
 514         conversation = find_or_create_conversation(pinfo);
 515         conversation_set_dissector(conversation, fb_zero_handle);
 516         dissect_fb_zero(tvb, pinfo, tree, data);
 517         return true;
 518     }
 519
 520     return false;
 521 }
 522
 523 void
 524 proto_register_fb_zero(void)
 525 {
 526     static hf_register_info hf[] = {
 527         { &hf_fb_zero_puflags,
 528             { "Public Flags", "fb_zero.puflags",
 529               FT_UINT8, BASE_HEX, NULL, 0x0,
 530               "Specifying per-packet public flags", HFILL }
 531         },
 532         { &hf_fb_zero_puflags_vrsn,
 533             { "Version", "fb_zero.puflags.version",
 534               FT_BOOLEAN, 8, TFS(&tfs_yes_no), PUFLAGS_VRSN,
 535               "Signifies that this packet also contains the version of the FB Zero protocol", HFILL }
 536         },
 537         { &hf_fb_zero_puflags_unknown,
 538             { "Unknown", "fb_zero.puflags.unknown",
 539               FT_UINT8, BASE_HEX, NULL, PUFLAGS_UNKN,
 540               NULL, HFILL }
 541         },
 542
 543         { &hf_fb_zero_version,
 544             { "Version", "fb_zero.version",
 545               FT_STRING, BASE_NONE, NULL, 0x0,
 546               "32 bit opaque tag that represents the version of the ZB Zero (Always QTV)", HFILL }
 547         },
 548         { &hf_fb_zero_length,
 549             { "Length", "fb_zero.length",
 550               FT_UINT32, BASE_DEC, NULL, 0x0,
 551               NULL, HFILL }
 552         },
 553         { &hf_fb_zero_tag,
 554             { "Tag", "fb_zero.tag",
 555               FT_STRING, BASE_NONE, NULL, 0x0,
 556               NULL, HFILL }
 557         },
 558         { &hf_fb_zero_tag_number,
 559             { "Tag Number", "fb_zero.tag_number",
 560               FT_UINT16, BASE_DEC, NULL, 0x0,
 561               NULL, HFILL }
 562         },
 563         { &hf_fb_zero_tags,
 564             { "Tag/value", "fb_zero.tags",
 565               FT_NONE, BASE_NONE, NULL, 0x0,
 566               NULL, HFILL }
 567         },
 568         { &hf_fb_zero_tag_type,
 569             { "Tag Type", "fb_zero.tag_type",
 570               FT_STRING, BASE_NONE, NULL, 0x0,
 571               NULL, HFILL }
 572         },
 573         { &hf_fb_zero_tag_offset_end,
 574             { "Tag offset end", "fb_zero.tag_offset_end",
 575               FT_UINT32, BASE_DEC, NULL, 0x0,
 576               NULL, HFILL }
 577         },
 578         { &hf_fb_zero_tag_length,
 579             { "Tag length", "fb_zero.tag_offset_length",
 580               FT_UINT32, BASE_DEC, NULL, 0x0,
 581               NULL, HFILL }
 582         },
 583         { &hf_fb_zero_tag_value,
 584             { "Tag/value", "fb_zero.tag_value",
 585               FT_BYTES, BASE_NONE, NULL, 0x0,
 586               NULL, HFILL }
 587         },
 588         { &hf_fb_zero_tag_sni,
 589             { "Server Name Indication", "fb_zero.tag.sni",
 590               FT_STRING, BASE_NONE, NULL, 0x0,
 591               "The fully qualified DNS name of the server, canonicalised to lowercase with no trailing period", HFILL }
 592         },
 593         { &hf_fb_zero_tag_vers,
 594             { "Version", "fb_zero.tag.version",
 595               FT_STRING, BASE_NONE, NULL, 0x0,
 596               "Version of FB Zero supported", HFILL }
 597         },
 598         { &hf_fb_zero_tag_sno,
 599             { "Server nonce", "fb_zero.tag.sno",
 600               FT_BYTES, BASE_NONE, NULL, 0x0,
 601               NULL, HFILL }
 602         },
 603         { &hf_fb_zero_tag_aead,
 604             { "Authenticated encryption algorithms", "fb_zero.tag.aead",
 605               FT_STRING, BASE_NONE, NULL, 0x0,
 606               "A list of tags, in preference order, specifying the AEAD primitives supported by the server", HFILL }
 607         },
 608         { &hf_fb_zero_tag_scid,
 609             { "Server Config ID", "fb_zero.tag.scid",
 610               FT_BYTES, BASE_NONE, NULL, 0x0,
 611               "An opaque, 16-byte identifier for this server config", HFILL }
 612         },
 613         { &hf_fb_zero_tag_time,
 614             { "Time", "fb_zero.tag.time",
 615               FT_UINT32, BASE_DEC, NULL, 0x0,
 616               NULL, HFILL }
 617         },
 618         { &hf_fb_zero_tag_alpn,
 619             { "ALPN", "fb_zero.tag.alpn",
 620               FT_STRING, BASE_NONE, NULL, 0x0,
 621               "Application-Layer Protocol Negotiation supported", HFILL }
 622         },
 623         { &hf_fb_zero_tag_pubs,
 624             { "Public value", "fb_zero.tag.pubs",
 625               FT_UINT24, BASE_DEC_HEX, NULL, 0x0,
 626               "A list of public values, 24-bit, little-endian length prefixed", HFILL }
 627         },
 628         { &hf_fb_zero_tag_kexs,
 629             { "Key exchange algorithms", "fb_zero.tag.kexs",
 630               FT_STRING, BASE_NONE, NULL, 0x0,
 631               "A list of tags, in preference order, specifying the key exchange algorithms that the server supports", HFILL }
 632         },
 633         { &hf_fb_zero_tag_nonc,
 634             { "Client nonce", "fb_zero.tag.nonc",
 635               FT_BYTES, BASE_NONE, NULL, 0x0,
 636               "32 bytes consisting of 4 bytes of timestamp (big-endian, UNIX epoch seconds), 8 bytes of server orbit and 20 bytes of random data", HFILL }
 637         },
 638         { &hf_fb_zero_tag_unknown,
 639             { "Unknown tag", "fb_zero.tag.unknown",
 640               FT_BYTES, BASE_NONE, NULL, 0x0,
 641               NULL, HFILL }
 642         },
 643         { &hf_fb_zero_padding,
 644             { "Padding", "fb_zero.padding",
 645               FT_BYTES, BASE_NONE, NULL, 0x0,
 646               NULL, HFILL }
 647         },
 648         { &hf_fb_zero_payload,
 649             { "Payload", "fb_zero.payload",
 650               FT_BYTES, BASE_NONE, NULL, 0x0,
 651               "Fb Zero Payload..", HFILL }
 652         },
 653         { &hf_fb_zero_unknown,
 654             { "Unknown", "fb_zero.unknown",
 655               FT_BYTES, BASE_NONE, NULL, 0x0,
 656               "Unknown Data", HFILL }
 657         },
 658     };
 659
 660
 661     static int *ett[] = {
 662         &ett_fb_zero,
 663         &ett_fb_zero_puflags,
 664         &ett_fb_zero_prflags,
 665         &ett_fb_zero_ft,
 666         &ett_fb_zero_ftflags,
 667         &ett_fb_zero_tag_value
 668     };
 669
 670     static ei_register_info ei[] = {
 671         { &ei_fb_zero_tag_undecoded, { "fb_zero.tag.undecoded", PI_UNDECODED, PI_NOTE, "Dissector for FB Zero Tag code not implemented, Contact Wireshark developers if you want this supported", EXPFILL }},
 672         { &ei_fb_zero_tag_offset_end_invalid, { "fb_zero.offset_end.invalid", PI_PROTOCOL, PI_ERROR, "Invalid tag end offset", EXPFILL }},
 673         { &ei_fb_zero_length_invalid, { "fb_zero.length.invalid", PI_PROTOCOL, PI_WARN, "Invalid length", EXPFILL }},
 674     };
 675
 676     expert_module_t *expert_fb_zero;
 677
 678     proto_fb_zero = proto_register_protocol("(Facebook) Zero Protocol", "FBZERO", "fb_zero");
 679
 680     fb_zero_handle = register_dissector("fb_zero", dissect_fb_zero, proto_fb_zero);
 681
 682     proto_register_field_array(proto_fb_zero, hf, array_length(hf));
 683     proto_register_subtree_array(ett, array_length(ett));
 684
 685     expert_fb_zero = expert_register_protocol(proto_fb_zero);
 686     expert_register_field_array(expert_fb_zero, ei, array_length(ei));
 687 }
 688
 689 void
 690 proto_reg_handoff_fb_zero(void)
 691 {
 692
 693     heur_dissector_add("tcp", dissect_fb_zero_heur, "FBZero (QUIC) over TCP", "fb_zero", proto_fb_zero, HEURISTIC_ENABLE);
 694
 695 }
 696
 697
 698 /*
 699  * Editor modelines  -  https://www.wireshark.org/tools/modelines.html
 700  *
 701  * Local variables:
 702  * c-basic-offset: 4
 703  * tab-width: 8
 704  * indent-tabs-mode: nil
 705  * End:
 706  *
 707  * vi: set shiftwidth=4 tabstop=8 expandtab:
 708  * :indentSize=4:tabSize=8:noTabs=true:
 709  */