epan/dissectors/packet-ymsg.c

   1 /* packet-ymsg.c
   2  * Routines for Yahoo Messenger YMSG protocol packet version 13 dissection
   3  * Copyright 2003, Wayne Parrott <wayne_p@pacific.net.au>
   4  * Copied from packet-yhoo.c and updated
   5  *
   6  * $Id$
   7  *
   8  * Wireshark - Network traffic analyzer
   9  * By Gerald Combs <gerald@wireshark.org>
  10  * Copyright 1998 Gerald Combs
  11  *
  12  * This program is free software; you can redistribute it and/or
  13  * modify it under the terms of the GNU General Public License
  14  * as published by the Free Software Foundation; either version 2
  15  * of the License, or (at your option) any later version.
  16  *
  17  * This program is distributed in the hope that it will be useful,
  18  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  19  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20  * GNU General Public License for more details.
  21  *
  22  * You should have received a copy of the GNU General Public License
  23  * along with this program; if not, write to the Free Software
  24  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  25  */
  26
  27 #ifdef HAVE_CONFIG_H
  28 # include "config.h"
  29 #endif
  30
  31 #include <stdio.h>
  32
  33 #include <string.h>
  34 #include <glib.h>
  35 #include <epan/packet.h>
  36 #include <epan/emem.h>
  37
  38 #include "packet-tcp.h"
  39 #include <epan/prefs.h>
  40
  41 static int proto_ymsg = -1;
  42 static int hf_ymsg_version = -1;
  43 static int hf_ymsg_len = -1;
  44 static int hf_ymsg_service = -1;
  45 static int hf_ymsg_status = -1;
  46 static int hf_ymsg_session_id = -1;
  47
  48 static int hf_ymsg_content = -1;
  49 static int hf_ymsg_content_line = -1;
  50 static int hf_ymsg_content_line_key = -1;
  51 static int hf_ymsg_content_line_value = -1;
  52
  53 static gint ett_ymsg = -1;
  54 static gint ett_ymsg_content = -1;
  55 static gint ett_ymsg_content_line = -1;
  56
  57 #define TCP_PORT_YMSG   23      /* XXX - this is Telnet! */
  58 #define TCP_PORT_YMSG_2 25      /* And this is SMTP! */
  59 #define TCP_PORT_YMSG_3 5050    /* This, however, is regular Yahoo Messenger */
  60
  61 /* desegmentation of YMSG over TCP */
  62 static gboolean ymsg_desegment = TRUE;
  63
  64 /*
  65  * This is from yahoolib2.c from libyahoo2.
  66  *
  67  * See also
  68  *
  69  *      http://libyahoo2.sourceforge.net/ymsg-9.txt
  70  *
  71  * and
  72  *
  73  *      http://www.venkydude.com/articles/yahoo.htm
  74  *
  75  * and
  76  *
  77  *      http://www.cse.iitb.ac.in/~varunk/YahooProtocol.htm
  78  *
  79  * and
  80  *
  81  *      http://www.geocrawler.com/archives/3/4893/2002/1/0/7459037/
  82  *
  83  * and
  84  *
  85  *      http://www.geocities.com/ziggycubbe/ym.html
  86  */
  87
  88 /* Service constants */
  89 enum yahoo_service { /* these are easier to see in hex */
  90         YAHOO_SERVICE_LOGON = 1,
  91         YAHOO_SERVICE_LOGOFF,
  92         YAHOO_SERVICE_ISAWAY,
  93         YAHOO_SERVICE_ISBACK,
  94         YAHOO_SERVICE_IDLE, /* 5 (placemarker) */
  95         YAHOO_SERVICE_MESSAGE,
  96         YAHOO_SERVICE_IDACT,
  97         YAHOO_SERVICE_IDDEACT,
  98         YAHOO_SERVICE_MAILSTAT,
  99         YAHOO_SERVICE_USERSTAT, /* 0xa */
 100         YAHOO_SERVICE_NEWMAIL,
 101         YAHOO_SERVICE_CHATINVITE,
 102         YAHOO_SERVICE_CALENDAR,
 103         YAHOO_SERVICE_NEWPERSONALMAIL,
 104         YAHOO_SERVICE_NEWCONTACT,
 105         YAHOO_SERVICE_ADDIDENT, /* 0x10 */
 106         YAHOO_SERVICE_ADDIGNORE,
 107         YAHOO_SERVICE_PING,
 108         YAHOO_SERVICE_GOTGROUPRENAME, /* < 1, 36(old), 37(new) */
 109         YAHOO_SERVICE_SYSMESSAGE = 0x14,
 110         YAHOO_SERVICE_SKINNAME = 0x15,
 111         YAHOO_SERVICE_PASSTHROUGH2 = 0x16,
 112         YAHOO_SERVICE_CONFINVITE = 0x18,
 113         YAHOO_SERVICE_CONFLOGON,
 114         YAHOO_SERVICE_CONFDECLINE,
 115         YAHOO_SERVICE_CONFLOGOFF,
 116         YAHOO_SERVICE_CONFADDINVITE,
 117         YAHOO_SERVICE_CONFMSG,
 118         YAHOO_SERVICE_CHATLOGON,
 119         YAHOO_SERVICE_CHATLOGOFF,
 120         YAHOO_SERVICE_CHATMSG = 0x20,
 121         YAHOO_SERVICE_GAMELOGON = 0x28,
 122         YAHOO_SERVICE_GAMELOGOFF,
 123         YAHOO_SERVICE_GAMEMSG = 0x2a,
 124         YAHOO_SERVICE_FILETRANSFER = 0x46,
 125         YAHOO_SERVICE_VOICECHAT = 0x4A,
 126         YAHOO_SERVICE_NOTIFY,
 127         YAHOO_SERVICE_VERIFY,
 128         YAHOO_SERVICE_P2PFILEXFER,
 129         YAHOO_SERVICE_PEERTOPEER = 0x4F,        /* Checks if P2P possible */
 130         YAHOO_SERVICE_WEBCAM,
 131         YAHOO_SERVICE_AUTHRESP = 0x54,
 132         YAHOO_SERVICE_LIST,
 133         YAHOO_SERVICE_AUTH = 0x57,
 134         YAHOO_SERVICE_ADDBUDDY = 0x83,
 135         YAHOO_SERVICE_REMBUDDY,
 136         YAHOO_SERVICE_IGNORECONTACT,    /* > 1, 7, 13 < 1, 66, 13, 0*/
 137         YAHOO_SERVICE_REJECTCONTACT,
 138         YAHOO_SERVICE_GROUPRENAME = 0x89, /* > 1, 65(new), 66(0), 67(old) */
 139         YAHOO_SERVICE_CHATONLINE = 0x96, /* > 109(id), 1, 6(abcde) < 0,1*/
 140         YAHOO_SERVICE_CHATGOTO,
 141         YAHOO_SERVICE_CHATJOIN, /* > 1 104-room 129-1600326591 62-2 */
 142         YAHOO_SERVICE_CHATLEAVE,
 143         YAHOO_SERVICE_CHATEXIT = 0x9b,
 144         YAHOO_SERVICE_CHATADDINVITE = 0x9d,
 145         YAHOO_SERVICE_CHATLOGOUT = 0xa0,
 146         YAHOO_SERVICE_CHATPING,
 147         YAHOO_SERVICE_COMMENT = 0xa8,
 148         YAHOO_SERVICE_GAME_INVITE = 0xb7,
 149         YAHOO_SERVICE_STEALTH_PERM = 0xb9,
 150         YAHOO_SERVICE_STEALTH_SESSION = 0xba,
 151         YAHOO_SERVICE_AVATAR = 0xbc,
 152         YAHOO_SERVICE_PICTURE_CHECKSUM = 0xbd,
 153         YAHOO_SERVICE_PICTURE = 0xbe,
 154         YAHOO_SERVICE_PICTURE_UPDATE = 0xc1,
 155         YAHOO_SERVICE_PICTURE_UPLOAD = 0xc2,
 156         YAHOO_SERVICE_YAB_UPDATE = 0xc4,
 157         YAHOO_SERVICE_Y6_VISIBLE_TOGGLE = 0xc5, /* YMSG13, key 13: 2 = invisible, 1 = visible */
 158         YAHOO_SERVICE_Y6_STATUS_UPDATE = 0xc6,  /* YMSG13 */
 159         YAHOO_SERVICE_PICTURE_STATUS = 0xc7,    /* YMSG13, key 213: 0 = none, 1 = avatar, 2 = picture */
 160         YAHOO_SERVICE_VERIFY_ID_EXISTS = 0xc8,
 161         YAHOO_SERVICE_AUDIBLE = 0xd0,
 162         YAHOO_SERVICE_Y7_PHOTO_SHARING = 0xd2,
 163         YAHOO_SERVICE_Y7_CONTACT_DETAILS = 0xd3,/* YMSG13 */
 164         YAHOO_SERVICE_Y7_CHAT_SESSION = 0xd4,
 165         YAHOO_SERVICE_Y7_AUTHORIZATION = 0xd6,  /* YMSG13 */
 166         YAHOO_SERVICE_Y7_FILETRANSFER = 0xdc,   /* YMSG13 */
 167         YAHOO_SERVICE_Y7_FILETRANSFERINFO,      /* YMSG13 */
 168         YAHOO_SERVICE_Y7_FILETRANSFERACCEPT,    /* YMSG13 */
 169         YAHOO_SERVICE_Y7_MINGLE = 0xe1, /* YMSG13 */
 170         YAHOO_SERVICE_Y7_CHANGE_GROUP = 0xe7, /* YMSG13 */
 171         YAHOO_SERVICE_WEBLOGIN = 0x0226,
 172         YAHOO_SERVICE_SMS_MSG = 0x02ea
 173 };
 174
 175 /* Message flags */
 176 enum yahoo_status {
 177         YAHOO_STATUS_AVAILABLE = 0,
 178         YAHOO_STATUS_BRB,
 179         YAHOO_STATUS_BUSY,
 180         YAHOO_STATUS_NOTATHOME,
 181         YAHOO_STATUS_NOTATDESK,
 182         YAHOO_STATUS_NOTINOFFICE,
 183         YAHOO_STATUS_ONPHONE,
 184         YAHOO_STATUS_ONVACATION,
 185         YAHOO_STATUS_OUTTOLUNCH,
 186         YAHOO_STATUS_STEPPEDOUT,
 187         YAHOO_STATUS_INVISIBLE = 12,
 188         YAHOO_STATUS_CUSTOM = 99,
 189         YAHOO_STATUS_IDLE = 999,
 190         YAHOO_STATUS_WEBLOGIN = 0x5a55aa55,
 191         YAHOO_STATUS_OFFLINE = 0x5a55aa56, /* don't ask */
 192         YAHOO_STATUS_TYPING = 0x16
 193 };
 194
 195 enum ypacket_status {
 196         YPACKET_STATUS_DISCONNECTED = -1,
 197         YPACKET_STATUS_DEFAULT = 0,
 198         YPACKET_STATUS_SERVERACK = 1,
 199         YPACKET_STATUS_GAME     = 0x2,
 200         YPACKET_STATUS_CONTINUED = 0x5,
 201         YPACKET_STATUS_INVISIBLE = 12,
 202         YPACKET_STATUS_NOTIFY = 0x16, /* TYPING */
 203         YPACKET_STATUS_WEBLOGIN = 0x5a55aa55
 204 };
 205
 206 struct yahoo_rawpacket
 207 {
 208         char ymsg[4];                   /* Packet identification string (YMSG) */
 209         unsigned char version[4];       /* 4 bytes, little endian? */
 210         unsigned char len[2];           /* length - little endian */
 211         unsigned char service[2];       /* service - little endian */
 212         unsigned char status[4];        /* Status - online, away etc.*/
 213         unsigned char session_id[4];    /* Session ID */
 214         char content[6];                /* 6 is the minimum size of the content */
 215 };
 216
 217 static const value_string ymsg_service_vals[] = {
 218         {YAHOO_SERVICE_LOGON, "Pager Logon"},
 219         {YAHOO_SERVICE_LOGOFF, "Pager Logoff"},
 220         {YAHOO_SERVICE_ISAWAY, "Is Away"},
 221         {YAHOO_SERVICE_ISBACK, "Is Back"},
 222         {YAHOO_SERVICE_IDLE, "Idle"},
 223         {YAHOO_SERVICE_MESSAGE, "Message"},
 224         {YAHOO_SERVICE_IDACT, "Activate Identity"},
 225         {YAHOO_SERVICE_IDDEACT, "Deactivate Identity"},
 226         {YAHOO_SERVICE_MAILSTAT, "Mail Status"},
 227         {YAHOO_SERVICE_USERSTAT, "User Status"},
 228         {YAHOO_SERVICE_NEWMAIL, "New Mail"},
 229         {YAHOO_SERVICE_CHATINVITE, "Chat Invitation"},
 230         {YAHOO_SERVICE_CALENDAR, "Calendar Reminder"},
 231         {YAHOO_SERVICE_NEWPERSONALMAIL, "New Personals Mail"},
 232         {YAHOO_SERVICE_NEWCONTACT, "New Friend"},
 233         {YAHOO_SERVICE_ADDIDENT, "Add Identity"},
 234         {YAHOO_SERVICE_ADDIGNORE, "Add Ignore"},
 235         {YAHOO_SERVICE_PING, "Ping"},
 236         {YAHOO_SERVICE_GOTGROUPRENAME, "YAHOO_SERVICE_GOTGROUPRENAME"},
 237         {YAHOO_SERVICE_SYSMESSAGE, "System Message"},
 238         {YAHOO_SERVICE_SKINNAME, "YAHOO_SERVICE_SKINNAME"},
 239         {YAHOO_SERVICE_PASSTHROUGH2, "Passthrough 2"},
 240         {YAHOO_SERVICE_CONFINVITE, "Conference Invitation"},
 241         {YAHOO_SERVICE_CONFLOGON, "Conference Logon"},
 242         {YAHOO_SERVICE_CONFDECLINE, "Conference Decline"},
 243         {YAHOO_SERVICE_CONFLOGOFF, "Conference Logoff"},
 244         {YAHOO_SERVICE_CONFADDINVITE, "Conference Additional Invitation"},
 245         {YAHOO_SERVICE_CONFMSG, "Conference Message"},
 246         {YAHOO_SERVICE_CHATLOGON, "Chat Logon"},
 247         {YAHOO_SERVICE_CHATLOGOFF, "Chat Logoff"},
 248         {YAHOO_SERVICE_CHATMSG, "Chat Message"},
 249         {YAHOO_SERVICE_GAMELOGON, "Game Logon"},
 250         {YAHOO_SERVICE_GAMELOGOFF, "Game Logoff"},
 251         {YAHOO_SERVICE_GAMEMSG, "Game Message"},
 252         {YAHOO_SERVICE_FILETRANSFER, "File Transfer"},
 253         {YAHOO_SERVICE_VOICECHAT, "Voice Chat"},
 254         {YAHOO_SERVICE_NOTIFY, "YAHOO_SERVICE_NOTIFY"},
 255         {YAHOO_SERVICE_VERIFY, "YAHOO_SERVICE_VERIFY"},
 256         {YAHOO_SERVICE_P2PFILEXFER, "YAHOO_SERVICE_P2PFILEXFER"},
 257         {YAHOO_SERVICE_PEERTOPEER, "YAHOO_SERVICE_PEERTOPEER"},
 258         {YAHOO_SERVICE_WEBCAM, "YAHOO_SERVICE_WEBCAM"},
 259         {YAHOO_SERVICE_AUTHRESP, "YAHOO_SERVICE_AUTHRESP"},
 260         {YAHOO_SERVICE_LIST, "YAHOO_SERVICE_LIST"},
 261         {YAHOO_SERVICE_AUTH, "YAHOO_SERVICE_AUTH"},
 262         {YAHOO_SERVICE_ADDBUDDY, "YAHOO_SERVICE_ADDBUDDY"},
 263         {YAHOO_SERVICE_REMBUDDY, "YAHOO_SERVICE_REMBUDDY"},
 264         {YAHOO_SERVICE_IGNORECONTACT, "YAHOO_SERVICE_IGNORECONTACT"},
 265         {YAHOO_SERVICE_REJECTCONTACT, "YAHOO_SERVICE_REJECTCONTACT"},
 266         {YAHOO_SERVICE_GROUPRENAME, "Group Renamed"},
 267         {YAHOO_SERVICE_CHATONLINE, "YAHOO_SERVICE_CHATONLINE"},
 268         {YAHOO_SERVICE_CHATGOTO, "YAHOO_SERVICE_CHATGOTO"},
 269         {YAHOO_SERVICE_CHATJOIN, "YAHOO_SERVICE_CHATJOIN"},
 270         {YAHOO_SERVICE_CHATLEAVE, "YAHOO_SERVICE_CHATLEAVE"},
 271         {YAHOO_SERVICE_CHATEXIT, "YAHOO_SERVICE_CHATEXIT"},
 272         {YAHOO_SERVICE_CHATADDINVITE, "YAHOO_SERVICE_CHATADDINVITE"},
 273         {YAHOO_SERVICE_CHATLOGOUT, "YAHOO_SERVICE_CHATLOGOUT"},
 274         {YAHOO_SERVICE_CHATPING, "YAHOO_SERVICE_CHATPING"},
 275         {YAHOO_SERVICE_COMMENT, "YAHOO_SERVICE_COMMENT"},
 276         {YAHOO_SERVICE_GAME_INVITE,"YAHOO_SERVICE_GAME_INVITE "},
 277         {YAHOO_SERVICE_STEALTH_PERM, "YAHOO_SERVICE_STEALTH_PERM"},
 278         {YAHOO_SERVICE_STEALTH_SESSION, "YAHOO_SERVICE_STEALTH_SESSION"},
 279         {YAHOO_SERVICE_AVATAR, "YAHOO_SERVICE_AVATAR"},
 280         {YAHOO_SERVICE_PICTURE_CHECKSUM, "YAHOO_SERVICE_PICTURE_CHECKSUM"},
 281         {YAHOO_SERVICE_PICTURE, "YAHOO_SERVICE_PICTURE"},
 282         {YAHOO_SERVICE_PICTURE_UPDATE, "YAHOO_SERVICE_PICTURE_UPDATE"},
 283         {YAHOO_SERVICE_PICTURE_UPLOAD, "YAHOO_SERVICE_PICTURE_UPLOAD"},
 284         {YAHOO_SERVICE_YAB_UPDATE,"YAHOO_SERVICE_YAB_UPDATE"},
 285         {YAHOO_SERVICE_Y6_VISIBLE_TOGGLE, "YAHOO_SERVICE_Y6_VISIBLE_TOGGLE"},
 286         {YAHOO_SERVICE_Y6_STATUS_UPDATE, "YAHOO_SERVICE_Y6_STATUS_UPDATE"},
 287         {YAHOO_SERVICE_PICTURE_STATUS, "YAHOO_SERVICE_PICTURE_STATUS"},
 288         {YAHOO_SERVICE_VERIFY_ID_EXISTS, "YAHOO_SERVICE_VERIFY_ID_EXISTS"},
 289         {YAHOO_SERVICE_AUDIBLE, "YAHOO_SERVICE_AUDIBLE"},
 290         {YAHOO_SERVICE_Y7_CONTACT_DETAILS,"YAHOO_SERVICE_Y7_CONTACT_DETAILS"},
 291         {YAHOO_SERVICE_Y7_CHAT_SESSION, "YAHOO_SERVICE_Y7_CHAT_SESSION"},
 292         {YAHOO_SERVICE_Y7_AUTHORIZATION,"YAHOO_SERVICE_Y7_AUTHORIZATION"},
 293         {YAHOO_SERVICE_Y7_FILETRANSFER,"YAHOO_SERVICE_Y7_FILETRANSFER"},
 294         {YAHOO_SERVICE_Y7_FILETRANSFERINFO,"YAHOO_SERVICE_Y7_FILETRANSFERINFO"},
 295         {YAHOO_SERVICE_Y7_FILETRANSFERACCEPT,"YAHOO_SERVICE_Y7_FILETRANSFERACCEPT"},
 296         {YAHOO_SERVICE_Y7_CHANGE_GROUP, "YAHOO_SERVICE_Y7_CHANGE_GROUP"},
 297         {YAHOO_SERVICE_WEBLOGIN, "YAHOO_SERVICE_WEBLOGIN"},
 298         {YAHOO_SERVICE_SMS_MSG, "YAHOO_SERVICE_SMS_MSG"},
 299         {0, NULL}
 300 };
 301
 302 static const value_string ymsg_status_vals[] = {
 303         {YPACKET_STATUS_DISCONNECTED,"Disconnected"},
 304         {YPACKET_STATUS_DEFAULT,""},
 305         {YPACKET_STATUS_SERVERACK,"Server Ack"},
 306         {YPACKET_STATUS_GAME,"Playing Game"},
 307         {YPACKET_STATUS_CONTINUED,"More Packets??"},
 308         {YPACKET_STATUS_NOTIFY, "Notify"},
 309         {YPACKET_STATUS_WEBLOGIN,"Web Login"},
 310         {0, NULL}
 311 };
 312
 313 static guint get_ymsg_pdu_len(tvbuff_t *tvb, int offset);
 314 static void dissect_ymsg_pdu(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree);
 315
 316 /* Find the end of the current content line and return its length */
 317 static int get_content_item_length(tvbuff_t *tvb, int offset)
 318 {
 319         int origoffset = offset;
 320
 321         /* Keep reading until the magic delimiter (or end of tvb) is found */
 322         while (tvb_length_remaining(tvb, offset) >= 2) {
 323                 if (tvb_get_ntohs(tvb, offset) == 0xc080) {
 324                         break;
 325                 }
 326                 offset++;
 327         }
 328         return offset - origoffset;
 329 }
 330
 331
 332 static gboolean
 333 dissect_ymsg(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
 334 {
 335
 336   if (tvb_memeql(tvb, 0, "YMSG", 4) == -1) {
 337     /* Not a Yahoo Messenger packet. */
 338     return FALSE;
 339   }
 340
 341   tcp_dissect_pdus(tvb, pinfo, tree, ymsg_desegment, 8, get_ymsg_pdu_len,
 342                    dissect_ymsg_pdu);
 343   return TRUE;
 344 }
 345
 346 static guint
 347 get_ymsg_pdu_len(tvbuff_t *tvb, int offset)
 348 {
 349   guint16 plen;
 350
 351   /*
 352    * Get the length of the YMSG packet.
 353    */
 354   plen = tvb_get_ntohs(tvb, offset + 8);
 355
 356   /*
 357    * That length doesn't include the length of the header itself; add that in.
 358    */
 359   return plen + 20;
 360 }
 361
 362 static void
 363 dissect_ymsg_pdu(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
 364 {
 365         proto_tree      *ymsg_tree, *ti;
 366         proto_item      *content_item;
 367         proto_tree      *content_tree;
 368         char *keybuf;
 369         char *valbuf;
 370         int headersize = sizeof(struct yahoo_rawpacket)-6;
 371         int keylen = 0;
 372         int vallen = 0;
 373         int offset = 0;
 374         int content_len = 0;
 375
 376         if (check_col(pinfo->cinfo, COL_PROTOCOL))
 377                 col_set_str(pinfo->cinfo, COL_PROTOCOL, "YMSG");
 378
 379         offset = 0;
 380         if (check_col(pinfo->cinfo, COL_INFO)) {
 381                 col_add_fstr(pinfo->cinfo, COL_INFO,
 382                         "%s, %s",
 383                         val_to_str(tvb_get_ntohs(tvb, offset + 10),
 384                                  ymsg_service_vals, "Unknown Service: %u"),
 385                         val_to_str(tvb_get_ntohl(tvb, offset + 12),
 386                                  ymsg_status_vals, "Unknown Status: %u")
 387                 );
 388         }
 389
 390         if (tree) {
 391                 ti = proto_tree_add_item(tree, proto_ymsg, tvb, offset, -1, FALSE);
 392                 ymsg_tree = proto_item_add_subtree(ti, ett_ymsg);
 393
 394                 offset += 4; /* skip the YMSG string */
 395
 396                 /* Version */
 397                 proto_tree_add_item(ymsg_tree, hf_ymsg_version, tvb, offset, 2, FALSE);
 398                 offset += 2;
 399
 400                 offset += 2;    /* XXX - padding? */
 401
 402                 /* Length */
 403                 content_len = tvb_get_ntohs(tvb, offset);
 404                 proto_tree_add_item(ymsg_tree, hf_ymsg_len, tvb, offset, 2, FALSE);
 405                 offset += 2;
 406
 407                 /* Service */
 408                 proto_tree_add_item(ymsg_tree, hf_ymsg_service, tvb, offset, 2, FALSE);
 409                 offset += 2;
 410
 411                 /* Status */
 412                 proto_tree_add_item(ymsg_tree, hf_ymsg_status, tvb, offset, 4, FALSE);
 413                 offset += 4;
 414
 415                 /* Session id */
 416                 proto_tree_add_item(ymsg_tree, hf_ymsg_session_id, tvb, offset, 4, TRUE);
 417                 offset += 4;
 418
 419                 /* Contents */
 420                 if (content_len) {
 421                         /* Create content subtree */
 422                         content_item = proto_tree_add_item(ymsg_tree, hf_ymsg_content, tvb,
 423                                                            offset, -1, TRUE);
 424                         content_tree = proto_item_add_subtree(content_item, ett_ymsg_content);
 425
 426                         /* Each entry consists of:
 427                            <key string> <delimiter> <value string> <delimiter>
 428                         */
 429
 430                         /* Parse and show each line of the contents */
 431                         for (;;)
 432                         {
 433                                 proto_item  *ti = NULL;
 434                                 proto_tree  *content_line_tree = NULL;
 435
 436                                 /* Don't continue unless there is room for another whole item.
 437                                    (including 2 2-byte delimiters */
 438                                 if (offset >= (headersize+content_len-4))
 439                                 {
 440                                         break;
 441                                 }
 442
 443                                 /* Get the length of the key */
 444                                 keylen = get_content_item_length(tvb, offset);
 445                                 /* Extract the key */
 446                                 keybuf = tvb_format_text(tvb, offset, keylen);
 447
 448                                 /* Get the length of the value */
 449                                 vallen = get_content_item_length(tvb, offset+keylen+2);
 450                                 /* Extract the value */
 451                                 valbuf = tvb_format_text(tvb, offset+keylen+2, vallen);
 452
 453                                 /* Add a text item with the key... */
 454                                 ti =  proto_tree_add_string_format(content_tree, hf_ymsg_content_line, tvb,
 455                                                                    offset, keylen+2+vallen+2,
 456                                                                    "", "%s:%s", keybuf, valbuf);
 457                                 content_line_tree = proto_item_add_subtree(ti, ett_ymsg_content_line);
 458
 459                                 /* And add the key and value separately inside */
 460                                 proto_tree_add_item(content_line_tree, hf_ymsg_content_line_key, tvb,
 461                                                     offset, keylen, FALSE);
 462                                 proto_tree_add_item(content_line_tree, hf_ymsg_content_line_value, tvb,
 463                                                     offset+keylen+2, vallen, FALSE);
 464
 465                                 /* Move beyone key and value lines */
 466                                 offset += keylen+2+vallen+2;
 467                         }
 468                 }
 469         }
 470
 471         return;
 472 }
 473
 474 void
 475 proto_register_ymsg(void)
 476 {
 477         static hf_register_info hf[] = {
 478                         { &hf_ymsg_version, {
 479                                 "Version", "ymsg.version", FT_UINT16, BASE_DEC,
 480                                 NULL, 0, "Packet version identifier", HFILL }},
 481                         { &hf_ymsg_len, {
 482                                 "Packet Length", "ymsg.len", FT_UINT16, BASE_DEC,
 483                                 NULL, 0, "Packet Length", HFILL }},
 484                         { &hf_ymsg_service, {
 485                                 "Service", "ymsg.service", FT_UINT16, BASE_DEC,
 486                                 VALS(ymsg_service_vals), 0, "Service Type", HFILL }},
 487                         { &hf_ymsg_status, {
 488                                 "Status", "ymsg.status", FT_UINT32, BASE_DEC,
 489                                 VALS(ymsg_status_vals), 0, "Message Type Flags", HFILL }},
 490                         { &hf_ymsg_session_id, {
 491                                 "Session ID", "ymsg.session_id", FT_UINT32, BASE_HEX,
 492                                 NULL, 0, "Connection ID", HFILL }},
 493
 494                         { &hf_ymsg_content, {
 495                                 "Content", "ymsg.content", FT_STRING, BASE_NONE,
 496                                 NULL, 0, "Data portion of the packet", HFILL }},
 497                         { &hf_ymsg_content_line, {
 498                                 "Content-line", "ymsg.content-line", FT_STRING, BASE_NONE,
 499                                 NULL, 0, "Data portion of the packet", HFILL }},
 500                         { &hf_ymsg_content_line_key, {
 501                                 "Key", "ymsg.content-line.key", FT_STRING, BASE_NONE,
 502                                 NULL, 0, "Content line key", HFILL }},
 503                         { &hf_ymsg_content_line_value, {
 504                                 "Value", "ymsg.content-line.value", FT_STRING, BASE_NONE,
 505                                 NULL, 0, "Content line value", HFILL }},
 506         };
 507         static gint *ett[] = {
 508                 &ett_ymsg,
 509                 &ett_ymsg_content,
 510                 &ett_ymsg_content_line
 511         };
 512         module_t *ymsg_module;
 513
 514         proto_ymsg = proto_register_protocol("Yahoo YMSG Messenger Protocol",
 515             "YMSG", "ymsg");
 516
 517         proto_register_field_array(proto_ymsg, hf, array_length(hf));
 518
 519         proto_register_subtree_array(ett, array_length(ett));
 520
 521         ymsg_module = prefs_register_protocol(proto_ymsg, NULL);
 522         prefs_register_bool_preference(ymsg_module, "desegment",
 523                                        "Reasssemble YMSG messages spanning multiple TCP segments",
 524                                        "Whether the YMSG dissector should reasssemble messages spanning multiple TCP segments. "
 525                                        "To use this option, you must also enable \"Allow subdissectors to reassemble TCP streams\" in the TCP protocol settings.",
 526                                        &ymsg_desegment);
 527 }
 528
 529 void
 530 proto_reg_handoff_ymsg(void)
 531 {
 532         /*
 533          * DO NOT register for port 23, as that's Telnet, or for port
 534          * 25, as that's SMTP.
 535          *
 536          * Also, DO NOT register for port 5050, as that's used by the
 537          * old and new Yahoo messenger protocols.
 538          *
 539          * Just register as a heuristic TCP dissector, and reject stuff
 540          * that doesn't begin with a YMSG signature.
 541          */
 542         heur_dissector_add("tcp", dissect_ymsg, proto_ymsg);
 543 }