packet-rtcp.c

   1 /* packet-rtcp.c
   2  *
   3  * Routines for RTCP dissection
   4  * RTCP = Real-time Transport Control Protocol
   5  *
   6  * Copyright 2000, Philips Electronics N.V.
   7  * Written by Andreas Sikkema <andreas.sikkema@philips.com>
   8  *
   9  * Ethereal - Network traffic analyzer
  10  * By Gerald Combs <gerald@zing.org>
  11  * Copyright 1998 Gerald Combs
  12  *
  13  *
  14  * This program is free software; you can redistribute it and/or
  15  * modify it under the terms of the GNU General Public License
  16  * as published by the Free Software Foundation; either version 2
  17  * of the License, or (at your option) any later version.
  18  *
  19  * This program is distributed in the hope that it will be useful,
  20  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  21  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  22  * GNU General Public License for more details.
  23  *
  24  * You should have received a copy of the GNU General Public License
  25  * along with this program; if not, write to the Free Software
  26  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  27  */
  28
  29 /*
  30  * This dissector tries to dissect the RTCP protocol according to Annex A
  31  * of ITU-T Recommendation H.225.0 (02/98) and RFC 1889
  32  * H.225.0 literally copies RFC 1889, but omitting a few sections.
  33  *
  34  * RTCP traffic is handled by an uneven UDP portnumber. This can be any
  35  * port number, but there is a registered port available, port 5005
  36  * See Annex B of ITU-T Recommendation H.225.0, section B.7
  37  *
  38  */
  39
  40
  41 #ifdef HAVE_CONFIG_H
  42 # include "config.h"
  43 #endif
  44
  45 #include <glib.h>
  46 #include "packet.h"
  47
  48 #ifdef HAVE_SYS_TYPES_H
  49 #  include <sys/types.h>
  50 #endif
  51
  52 #ifdef HAVE_NETINET_IN_H
  53 #  include <netinet/in.h>
  54 #endif
  55
  56 #include <stdio.h>
  57 #include <string.h>
  58
  59 #include "packet-rtcp.h"
  60 #if 0
  61 #include "packet-ntp.h"
  62 #endif
  63 #include "conversation.h"
  64
  65 /* Version is the first 2 bits of the first octet*/
  66 #define RTCP_VERSION(octet)     ((octet) >> 6)
  67
  68 /* Padding is the third bit; no need to shift, because true is any value
  69    other than 0! */
  70 #define RTCP_PADDING(octet)     ((octet) & 0x20)
  71
  72 /* Receiver/ Sender count is the 5 last bits  */
  73 #define RTCP_COUNT(octet)       ((octet) & 0x1F)
  74
  75 static const value_string rtcp_version_vals[] =
  76 {
  77         { 0, "Old VAT Version" },
  78         { 1, "First Draft Version" },
  79         { 2, "RFC 1889 Version" },
  80         { 0, NULL },
  81 };
  82
  83 /* RTCP packet types according to Section A.11.1 */
  84 #define RTCP_SR   200
  85 #define RTCP_RR   201
  86 #define RTCP_SDES 202
  87 #define RTCP_BYE  203
  88 #define RTCP_APP  204
  89 /* Supplemental H.261 specific RTCP packet types according to Section C.3.5 */
  90 #define RTCP_FIR  192
  91 #define RTCP_NACK 193
  92
  93 static const value_string rtcp_packet_type_vals[] =
  94 {
  95         { RTCP_SR,   "Sender Report" },
  96         { RTCP_RR,   "Receiver Report" },
  97         { RTCP_SDES, "Source description" },
  98         { RTCP_BYE,  "Goodbye" },
  99         { RTCP_APP,  "Application specific" },
 100         { RTCP_FIR,  "Full Intra-frame Request (H.261)" },
 101         { RTCP_NACK, "Negative Acknowledgement (H.261)" },
 102         { 0,         NULL },
 103 };
 104
 105 /* RTCP SDES types (Section A.11.2) */
 106 #define RTCP_SDES_END    0
 107 #define RTCP_SDES_CNAME  1
 108 #define RTCP_SDES_NAME   2
 109 #define RTCP_SDES_EMAIL  3
 110 #define RTCP_SDES_PHONE  4
 111 #define RTCP_SDES_LOC    5
 112 #define RTCP_SDES_TOOL   6
 113 #define RTCP_SDES_NOTE   7
 114 #define RTCP_SDES_PRIV   8
 115
 116 static const value_string rtcp_sdes_type_vals[] =
 117 {
 118         { RTCP_SDES_END,   "END" },
 119         { RTCP_SDES_CNAME, "CNAME (user and domain)" },
 120         { RTCP_SDES_NAME,  "NAME (common name)" },
 121         { RTCP_SDES_EMAIL, "EMAIL (e-mail address)" },
 122         { RTCP_SDES_PHONE, "PHONE (phone number)" },
 123         { RTCP_SDES_LOC,   "LOC (geographic location)" },
 124         { RTCP_SDES_TOOL,  "TOOL (name/version of source app)" },
 125         { RTCP_SDES_NOTE,  "NOTE (note about source)" },
 126         { RTCP_SDES_PRIV,  "PRIV (private extensions)" },
 127         { 0,               NULL },
 128 };
 129
 130 /* RTCP header fields                   */
 131 static int proto_rtcp                = -1;
 132 static int hf_rtcp_version           = -1;
 133 static int hf_rtcp_padding           = -1;
 134 static int hf_rtcp_rc                = -1;
 135 static int hf_rtcp_sc                = -1;
 136 static int hf_rtcp_pt                = -1;
 137 static int hf_rtcp_length            = -1;
 138 static int hf_rtcp_ssrc_sender       = -1;
 139 static int hf_rtcp_ntp               = -1;
 140 static int hf_rtcp_rtp_timestamp     = -1;
 141 static int hf_rtcp_sender_pkt_cnt    = -1;
 142 static int hf_rtcp_sender_oct_cnt    = -1;
 143 static int hf_rtcp_ssrc_source       = -1;
 144 static int hf_rtcp_ssrc_fraction     = -1;
 145 static int hf_rtcp_ssrc_cum_nr       = -1;
 146 /* First the 32 bit number, then the split
 147  * up 16 bit values */
 148 /* These two are added to a subtree */
 149 static int hf_rtcp_ssrc_ext_high_seq = -1;
 150 static int hf_rtcp_ssrc_high_seq     = -1;
 151 static int hf_rtcp_ssrc_high_cycles  = -1;
 152 static int hf_rtcp_ssrc_jitter       = -1;
 153 static int hf_rtcp_ssrc_lsr          = -1;
 154 static int hf_rtcp_ssrc_dlsr         = -1;
 155 static int hf_rtcp_ssrc_csrc         = -1;
 156 static int hf_rtcp_ssrc_type         = -1;
 157 static int hf_rtcp_ssrc_length       = -1;
 158 static int hf_rtcp_ssrc_text         = -1;
 159 static int hf_rtcp_ssrc_prefix_len   = -1;
 160 static int hf_rtcp_ssrc_prefix_string= -1;
 161 static int hf_rtcp_subtype           = -1;
 162 static int hf_rtcp_name_ascii        = -1;
 163 static int hf_rtcp_app_data          = -1;
 164 static int hf_rtcp_fsn               = -1;
 165 static int hf_rtcp_blp               = -1;
 166 static int hf_rtcp_padding_count     = -1;
 167 static int hf_rtcp_padding_data      = -1;
 168
 169 /* RTCP fields defining a sub tree */
 170 static gint ett_rtcp           = -1;
 171 static gint ett_ssrc           = -1;
 172 static gint ett_ssrc_item      = -1;
 173 static gint ett_ssrc_ext_high  = -1;
 174 static gint ett_sdes           = -1;
 175 static gint ett_sdes_item      = -1;
 176
 177 static address fake_addr;
 178 static int heur_init = FALSE;
 179
 180 static char rtcp_proto[] = "RTCP";
 181
 182 static gboolean dissect_rtcp_heur( tvbuff_t *tvb, packet_info *pinfo,
 183     proto_tree *tree );
 184
 185 void rtcp_add_address( const unsigned char* ip_addr, int prt )
 186 {
 187         address src_addr;
 188         conversation_t* pconv = ( conversation_t* ) NULL;
 189
 190         src_addr.type = AT_IPv4;
 191         src_addr.len = 4;
 192         src_addr.data = ip_addr;
 193
 194         /*
 195          * The first time the function is called let the udp dissector
 196          * know that we're interested in traffic
 197          */
 198         if ( ! heur_init ) {
 199                 heur_dissector_add( "udp", dissect_rtcp_heur, proto_rtcp );
 200                 heur_init = TRUE;
 201         }
 202
 203         /*
 204          * Check if the ip address and port combination is not
 205          * already registered
 206          */
 207         pconv = find_conversation( &src_addr, &fake_addr, PT_UDP, prt, 0, 0 );
 208
 209         /*
 210          * If not, add
 211          */
 212         if ( ! pconv ) {
 213                 conversation_new( &src_addr, &fake_addr, PT_UDP, (guint32) prt,
 214                     (guint32) 0, (void*) rtcp_proto, 0 );
 215         }
 216
 217 }
 218
 219 #if 0
 220 static void rtcp_init( void )
 221 {
 222         unsigned char* tmp_data;
 223         int i;
 224
 225         /* Create a fake adddress... */
 226         fake_addr.type = AT_IPv4;
 227         fake_addr.len = 4;
 228
 229         tmp_data = malloc( fake_addr.len );
 230         for ( i = 0; i < fake_addr.len; i++) {
 231                 tmp_data[i] = 0;
 232         }
 233         fake_addr.data = tmp_data;
 234 }
 235 #endif
 236
 237 static gboolean
 238 dissect_rtcp_heur( tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree )
 239 {
 240         conversation_t* pconv;
 241
 242         if (!proto_is_protocol_enabled(proto_rtcp))
 243                 return FALSE;   /* RTCP has been disabled */
 244
 245         /* This is a heuristic dissector, which means we get all the UDP
 246          * traffic not sent to a known dissector and not claimed by
 247          * a heuristic dissector called before us!
 248          * So we first check if the frame is really meant for us.
 249          */
 250         if ( ( pconv = find_conversation( &pi.src, &fake_addr, pi.ptype,
 251             pi.srcport, 0, 0 ) ) == NULL ) {
 252                 /*
 253                  * The source ip:port combination was not what we were
 254                  * looking for, check the destination
 255                  */
 256                 if ( ( pconv = find_conversation( &pi.dst, &fake_addr,
 257                     pi.ptype, pi.destport, 0, 0 ) ) == NULL ) {
 258                         return FALSE;
 259                 }
 260         }
 261
 262
 263         /*
 264          * An RTCP conversation always contains data
 265          */
 266         if ( pconv->data == NULL )
 267                 return FALSE;
 268
 269         /*
 270          * An RTCP conversation data always contains "RTCP"
 271          */
 272         if ( strcmp( pconv->data, rtcp_proto ) != 0 )
 273                 return FALSE;
 274
 275         /*
 276          * The message is a valid RTCP message!
 277          */
 278         dissect_rtcp( tvb, pinfo, tree );
 279
 280         return TRUE;
 281 }
 282
 283
 284 static int
 285 dissect_rtcp_nack( tvbuff_t *tvb, int offset, frame_data *fd, proto_tree *tree )
 286 {
 287         /* Packet type = FIR (H261) */
 288         proto_tree_add_uint( tree, hf_rtcp_rc, tvb, offset, 1, tvb_get_guint8( tvb, offset ) & 31 );
 289         offset++;
 290         /* Packet type, 8 bits  = APP */
 291         proto_tree_add_item( tree, hf_rtcp_pt, tvb, offset, 1, FALSE );
 292         offset++;
 293
 294         /* Packet length in 32 bit words minus one */
 295         proto_tree_add_uint( tree, hf_rtcp_length, tvb, offset, 2, tvb_get_ntohs( tvb, offset ) );
 296         offset += 2;
 297
 298         /* SSRC  */
 299         proto_tree_add_uint( tree, hf_rtcp_ssrc_source, tvb, offset, 4, tvb_get_ntohl( tvb, offset ) );
 300         offset += 4;
 301
 302         /* FSN, 16 bits */
 303         proto_tree_add_uint( tree, hf_rtcp_fsn, tvb, offset, 2, tvb_get_ntohs( tvb, offset ) );
 304         offset += 2;
 305
 306         /* BLP, 16 bits */
 307         proto_tree_add_uint( tree, hf_rtcp_blp, tvb, offset, 2, tvb_get_ntohs( tvb, offset ) );
 308         offset += 2;
 309
 310         return offset;
 311 }
 312
 313 static int
 314 dissect_rtcp_fir( tvbuff_t *tvb, int offset, frame_data *fd, proto_tree *tree )
 315 {
 316         /* Packet type = FIR (H261) */
 317         proto_tree_add_uint( tree, hf_rtcp_rc, tvb, offset, 1, tvb_get_guint8( tvb, offset ) & 31 );
 318         offset++;
 319         /* Packet type, 8 bits  = APP */
 320         proto_tree_add_item( tree, hf_rtcp_pt, tvb, offset, 1, FALSE );
 321         offset++;
 322
 323         /* Packet length in 32 bit words minus one */
 324         proto_tree_add_uint( tree, hf_rtcp_length, tvb, offset, 2, tvb_get_ntohs( tvb, offset ) );
 325         offset += 2;
 326
 327         /* SSRC  */
 328         proto_tree_add_uint( tree, hf_rtcp_ssrc_source, tvb, offset, 4, tvb_get_ntohl( tvb, offset ) );
 329         offset += 4;
 330
 331         return offset;
 332 }
 333
 334 static int
 335 dissect_rtcp_app( tvbuff_t *tvb, int offset, frame_data *fd, proto_tree *tree,
 336     unsigned int padding, unsigned int packet_len )
 337 {
 338         unsigned int counter = 0;
 339         char ascii_name[5];
 340
 341         /* SSRC / CSRC */
 342         proto_tree_add_uint( tree, hf_rtcp_ssrc_source, tvb, offset, 4, tvb_get_ntohl( tvb, offset ) );
 343         offset += 4;
 344         packet_len -= 4;
 345
 346         /* Name (ASCII) */
 347         for( counter = 0; counter < 4; counter++ )
 348             ascii_name[ counter ] = tvb_get_guint8( tvb, offset + counter );
 349         /* strncpy( ascii_name, pd + offset, 4 ); */
 350         ascii_name[4] = '\0';
 351         proto_tree_add_string( tree, hf_rtcp_name_ascii, tvb, offset, 4,
 352             ascii_name );
 353         offset += 4;
 354         packet_len -= 4;
 355
 356         /* Applications specific data */
 357         if ( padding ) {
 358                 /* If there's padding present, we have to remove that from the data part
 359                  * The last octet of the packet contains the length of the padding
 360                  */
 361                 packet_len -= tvb_get_guint8( tvb, offset + packet_len - 1 );
 362         }
 363         proto_tree_add_item( tree, hf_rtcp_app_data, tvb, offset, packet_len, FALSE );
 364         offset += packet_len;
 365
 366         return offset;
 367 }
 368
 369 static int
 370 dissect_rtcp_bye( tvbuff_t *tvb, int offset, frame_data *fd, proto_tree *tree,
 371     int count )
 372 {
 373         unsigned int chunk          = 1;
 374         unsigned int reason_length  = 0;
 375         unsigned int counter = 0;
 376         char* reason_text = NULL;
 377
 378         while ( chunk <= count ) {
 379                 /* source identifier, 32 bits */
 380                 proto_tree_add_uint( tree, hf_rtcp_ssrc_source, tvb, offset, 4, tvb_get_ntohl( tvb, offset ) );
 381                 offset += 4;
 382         }
 383
 384         /* Bye reason consists of an 8 bit length l and a string with length l */
 385         reason_length = tvb_get_guint8( tvb, offset );
 386         proto_tree_add_item( tree, hf_rtcp_ssrc_length, tvb, offset, 1, FALSE );
 387         offset++;
 388
 389         reason_text = ( char* ) malloc( reason_length + 1 );
 390         for ( counter = 0; counter < reason_length; counter++ ) reason_text[ counter ] = tvb_get_guint8( tvb, offset + counter );
 391         /* strncpy( reason_text, pd + offset, reason_length ); */
 392         reason_text[ reason_length ] = '\0';
 393         proto_tree_add_string( tree, hf_rtcp_ssrc_text, tvb, offset, reason_length, reason_text );
 394         free( reason_text );
 395         offset += reason_length;
 396
 397         return offset;
 398
 399 }
 400
 401 static int
 402 dissect_rtcp_sdes( tvbuff_t *tvb, int offset, frame_data *fd, proto_tree *tree,
 403     int count )
 404 {
 405         unsigned int chunk          = 1;
 406         proto_item *sdes_item;
 407         proto_tree *sdes_tree;
 408         proto_tree *sdes_item_tree;
 409         proto_item *ti;
 410         int start_offset;
 411         int items_start_offset;
 412         guint32 ssrc;
 413         unsigned int item_len       = 0;
 414         unsigned int sdes_type      = 0;
 415         unsigned int counter        = 0;
 416         unsigned int prefix_len     = 0;
 417         char *prefix_string = NULL;
 418
 419         while ( chunk <= count ) {
 420                 /* Create a subtree for this chunk; we don't yet know
 421                    the length. */
 422                 start_offset = offset;
 423
 424                 ssrc = tvb_get_ntohl( tvb, offset );
 425                 sdes_item = proto_tree_add_text(tree, tvb, offset, 0,
 426                     "Chunk %u, SSRC/CSRC %u", chunk, ssrc);
 427                 sdes_tree = proto_item_add_subtree( sdes_item, ett_sdes );
 428
 429                 /* SSRC_n source identifier, 32 bits */
 430                 proto_tree_add_uint( sdes_tree, hf_rtcp_ssrc_source, tvb, offset, 4, ssrc );
 431                 offset += 4;
 432
 433                 /* Create a subtree for the SDES items; we don't yet know
 434                    the length */
 435                 items_start_offset = offset;
 436                 ti = proto_tree_add_text(sdes_tree, tvb, offset, 0,
 437                     "SDES items" );
 438                 sdes_item_tree = proto_item_add_subtree( ti, ett_sdes_item );
 439
 440                 /*
 441                  * Not every message is ended with "null" bytes, so check for
 442                  * end of frame instead.
 443                  */
 444                 while ( ( tvb_get_guint8( tvb, offset ) != RTCP_SDES_END )
 445                     && ( tvb_length_remaining( tvb, offset) >= 2 ) ) {
 446                 /* while ( ( pd[ offset ] != RTCP_SDES_END ) && ( BYTES_ARE_IN_FRAME( offset, 2 ) ) ) { */
 447                         /* ID, 8 bits */
 448                         sdes_type = tvb_get_guint8( tvb, offset );
 449                         proto_tree_add_item( sdes_item_tree, hf_rtcp_ssrc_type, tvb, offset, 1, FALSE );
 450                         offset++;
 451
 452                         /* Item length, 8 bits */
 453                         item_len = tvb_get_guint8( tvb, offset );
 454                         proto_tree_add_item( sdes_item_tree, hf_rtcp_ssrc_length, tvb, offset, 1, FALSE );
 455                         offset++;
 456
 457                         if ( sdes_type == RTCP_SDES_PRIV ) {
 458                                 /* PRIV adds two items between the SDES length
 459                                  * and value - an 8 bit length giving the
 460                                  * length of a "prefix string", and the string.
 461                                  */
 462                                 prefix_len = tvb_get_guint8( tvb, offset );
 463                                 proto_tree_add_item( sdes_item_tree, hf_rtcp_ssrc_prefix_len, tvb, offset, 1, FALSE );
 464                                 offset++;
 465
 466                                 prefix_string = ( char * ) malloc( prefix_len + 1 );
 467                                 for ( counter = 0; counter < prefix_len; counter++ )
 468                                         prefix_string[ counter ] =
 469                                             tvb_get_guint8( tvb, offset + counter );
 470                                 /* strncpy( prefix_string, pd + offset, prefix_len ); */
 471                                 prefix_string[ prefix_len ] = '\0';
 472                                 proto_tree_add_string( sdes_item_tree, hf_rtcp_ssrc_prefix_string, tvb, offset, prefix_len, prefix_string );
 473                                 free( prefix_string );
 474                                 offset += prefix_len;
 475                         }
 476                         prefix_string = ( char * ) malloc( item_len + 1 );
 477                         for ( counter = 0; counter < item_len; counter++ )
 478                             prefix_string[ counter ] =
 479                                 tvb_get_guint8( tvb, offset + counter );
 480                         /* strncpy( prefix_string, pd + offset, item_len ); */
 481                         prefix_string[ item_len] = 0;
 482                         proto_tree_add_string( sdes_item_tree, hf_rtcp_ssrc_text, tvb, offset, item_len, prefix_string );
 483                         free( prefix_string );
 484                         offset += item_len;
 485                 }
 486
 487                 /* Set the length of the items subtree. */
 488                 proto_item_set_len(ti, offset - items_start_offset);
 489
 490                 /* 32 bits = 4 bytes, so.....
 491                  * If offset % 4 != 0, we divide offset by 4, add one and then
 492                  * multiply by 4 again to reach the boundary
 493                  */
 494                 if ( offset % 4 != 0 )
 495                         offset = ((offset / 4) + 1 ) * 4;
 496
 497                 /* Set the length of this chunk. */
 498                 proto_item_set_len(sdes_item, offset - start_offset);
 499
 500                 chunk++;
 501         }
 502
 503
 504         return offset;
 505 }
 506
 507 static int
 508 dissect_rtcp_rr( tvbuff_t *tvb, int offset, frame_data *fd, proto_tree *tree,
 509     int count )
 510 {
 511         unsigned int counter = 1;
 512         proto_tree *ssrc_tree = (proto_tree*) NULL;
 513         proto_tree *ssrc_sub_tree = (proto_tree*) NULL;
 514         proto_tree *high_sec_tree = (proto_tree*) NULL;
 515         proto_item *ti = (proto_item*) NULL;
 516         guint8 rr_flt;
 517         unsigned int cum_nr = 0;
 518
 519         while ( counter <= count ) {
 520                 /* Create a new subtree for a length of 24 bytes */
 521                 ti = proto_tree_add_text(tree, tvb, offset, 24,
 522                     "Source %u", counter );
 523                 ssrc_tree = proto_item_add_subtree( ti, ett_ssrc );
 524
 525                 /* SSRC_n source identifier, 32 bits */
 526                 proto_tree_add_uint( ssrc_tree, hf_rtcp_ssrc_source, tvb, offset, 4, tvb_get_ntohl( tvb, offset ) );
 527                 offset += 4;
 528
 529                 ti = proto_tree_add_text(ssrc_tree, tvb, offset, 20, "SSRC contents" );
 530                 ssrc_sub_tree = proto_item_add_subtree( ti, ett_ssrc_item );
 531
 532                 /* Fraction lost, 8bits */
 533                 rr_flt = tvb_get_guint8( tvb, offset );
 534                 proto_tree_add_uint_format( ssrc_sub_tree, hf_rtcp_ssrc_fraction, tvb,
 535                     offset, 1, rr_flt, "Fraction lost: %u / 256", rr_flt );
 536                 offset++;
 537
 538                 /* Cumulative number of packets lost, 24 bits */
 539                 cum_nr = tvb_get_ntohl( tvb, offset ) >> 8;
 540                 proto_tree_add_uint( ssrc_sub_tree, hf_rtcp_ssrc_cum_nr, tvb,
 541                     offset, 3, cum_nr );
 542                 offset += 3;
 543
 544                 /* Extended highest sequence nr received, 32 bits
 545                  * Just for the sake of it, let's add another subtree
 546                  * because this might be a little clearer
 547                  */
 548                 ti = proto_tree_add_uint( ssrc_tree, hf_rtcp_ssrc_ext_high_seq,
 549                     tvb, offset, 4, tvb_get_ntohl( tvb, offset ) );
 550                 high_sec_tree = proto_item_add_subtree( ti, ett_ssrc_ext_high );
 551                 /* Sequence number cycles */
 552                 proto_tree_add_uint( high_sec_tree, hf_rtcp_ssrc_high_cycles,
 553                     tvb, offset, 2, tvb_get_ntohs( tvb, offset ) );
 554                 offset += 2;
 555                 /* highest sequence number received */
 556                 proto_tree_add_uint( high_sec_tree, hf_rtcp_ssrc_high_seq,
 557                     tvb, offset, 2, tvb_get_ntohs( tvb, offset ) );
 558                 offset += 2;
 559
 560                 /* Interarrival jitter */
 561                 proto_tree_add_uint( ssrc_tree, hf_rtcp_ssrc_jitter, tvb,
 562                     offset, 4, tvb_get_ntohl( tvb, offset ) );
 563                 offset += 4;
 564
 565                 /* Last SR timestamp */
 566                 proto_tree_add_uint( ssrc_tree, hf_rtcp_ssrc_lsr, tvb,
 567                     offset, 4, tvb_get_ntohl( tvb, offset ) );
 568                 offset += 4;
 569
 570                 /* Delay since last SR timestamp */
 571                 proto_tree_add_uint( ssrc_tree, hf_rtcp_ssrc_dlsr, tvb,
 572                     offset, 4, tvb_get_ntohl( tvb, offset ) );
 573                 offset += 4;
 574                 counter++;
 575         }
 576
 577         return offset;
 578 }
 579
 580 static int
 581 dissect_rtcp_sr( tvbuff_t *tvb, int offset, frame_data *fd, proto_tree *tree,
 582     int count )
 583 {
 584 #if 0
 585         gchar buff[ NTP_TS_SIZE ];
 586         char* ptime = tvb_get_ptr( tvb, offset, 8 );
 587
 588         /* Retreive the NTP timestamp. Using the NTP dissector for this */
 589         ntp_fmt_ts( ptime, buff );
 590         proto_tree_add_string_format( tree, hf_rtcp_ntp, tvb, offset, 8, ( const char* ) &buff, "NTP timestamp: %s", &buff );
 591         free( ptime ); ??????????????????????????????????????????????????????????????????
 592         offset += 8;
 593 #else
 594         /*
 595          * XXX - RFC 1889 says this is an NTP timestamp, but that appears
 596          * not to be the case.
 597          */
 598         proto_tree_add_text(tree, tvb, offset, 4, "Timestamp, MSW: %u",
 599                 tvb_get_ntohl(tvb, offset));
 600         offset += 4;
 601         proto_tree_add_text(tree, tvb, offset, 4, "Timestamp, LSW: %u",
 602                 tvb_get_ntohl(tvb, offset));
 603         offset += 4;
 604 #endif
 605         /* RTP timestamp, 32 bits */
 606         proto_tree_add_uint( tree, hf_rtcp_rtp_timestamp, tvb, offset, 4, tvb_get_ntohl( tvb, offset ) );
 607         offset += 4;
 608         /* Sender's packet count, 32 bits */
 609         proto_tree_add_uint( tree, hf_rtcp_sender_pkt_cnt, tvb, offset, 4, tvb_get_ntohl( tvb, offset ) );
 610         offset += 4;
 611         /* Sender's octet count, 32 bits */
 612         proto_tree_add_uint( tree, hf_rtcp_sender_oct_cnt, tvb, offset, 4, tvb_get_ntohl( tvb, offset ) );
 613         offset += 4;
 614
 615         /* The rest of the packet is equal to the RR packet */
 616         if ( count > 0 )
 617                 offset = dissect_rtcp_rr( tvb, offset, fd, tree, count );
 618
 619         return offset;
 620 }
 621
 622 void
 623 dissect_rtcp( tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree )
 624 {
 625         proto_item *ti           = NULL;
 626         proto_tree *rtcp_tree    = NULL;
 627         unsigned int temp_byte   = 0;
 628         unsigned int padding_set = 0;
 629         unsigned int elem_count  = 0;
 630         unsigned int packet_type = 0;
 631         unsigned int offset      = 0;
 632         guint16 packet_length    = 0;
 633
 634         CHECK_DISPLAY_AS_DATA(proto_rtcp, tvb, pinfo, tree);
 635
 636         pinfo->current_proto = "RTCP";
 637
 638         if ( check_col( pinfo->fd, COL_PROTOCOL ) )   {
 639                 col_set_str( pinfo->fd, COL_PROTOCOL, "RTCP" );
 640         }
 641
 642         if ( check_col( pinfo->fd, COL_INFO) ) {
 643                 /* The second octet contains the packet type */
 644                 /* switch ( pd[ offset + 1 ] ) { */
 645                 switch ( tvb_get_guint8( tvb, 1 ) ) {
 646                         case RTCP_SR:
 647                                 col_set_str( pinfo->fd, COL_INFO, "Sender Report");
 648                                 break;
 649                         case RTCP_RR:
 650                                 col_set_str( pinfo->fd, COL_INFO, "Receiver Report");
 651                                 break;
 652                         case RTCP_SDES:
 653                                 col_set_str( pinfo->fd, COL_INFO, "Source Description");
 654                                 break;
 655                         case RTCP_BYE:
 656                                 col_set_str( pinfo->fd, COL_INFO, "Goodbye");
 657                                 break;
 658                         case RTCP_APP:
 659                                 col_set_str( pinfo->fd, COL_INFO, "Application defined");
 660                                 break;
 661                         case RTCP_FIR:
 662                                 col_set_str( pinfo->fd, COL_INFO, "Full Intra-frame Request (H.261)");
 663                                 break;
 664                         case RTCP_NACK:
 665                                 col_set_str( pinfo->fd, COL_INFO, "Negative Acknowledgement (H.261)");
 666                                 break;
 667                         default:
 668                                 col_set_str( pinfo->fd, COL_INFO, "Unknown packet type");
 669                                 break;
 670                 }
 671         }
 672
 673         if ( tree ) {
 674
 675                 /*
 676                  * Check if there are at least 4 bytes left in the frame,
 677                  * the last 16 bits of those is the length of the current
 678                  * RTCP message. The last compound message contains padding,
 679                  * that enables us to break from the while loop.
 680                  */
 681                 /* while ( BYTES_ARE_IN_FRAME( offset, 4 ) ) { */
 682                 while ( tvb_length_remaining( tvb, offset) >= 4 ) {
 683                         /*
 684                          * First retreive the packet_type
 685                          */
 686                         packet_type = tvb_get_guint8( tvb, offset + 1 );
 687
 688                         /*
 689                          * Check if it's a valid type
 690                          */
 691                         if ( ( packet_type < 192 ) || ( packet_type >  204 ) )
 692                                 break;
 693
 694                         /*
 695                          * get the packet-length for the complete RTCP packet
 696                          */
 697                         packet_length = ( tvb_get_ntohs( tvb, offset + 2 ) + 1 ) * 4;
 698
 699                         ti = proto_tree_add_item(tree, proto_rtcp, tvb, offset, packet_length, FALSE );
 700                         rtcp_tree = proto_item_add_subtree( ti, ett_rtcp );
 701
 702                         temp_byte = tvb_get_guint8( tvb, offset );
 703
 704                         proto_tree_add_uint( rtcp_tree, hf_rtcp_version, tvb,
 705                             offset, 1, RTCP_VERSION( temp_byte ) );
 706                         padding_set = RTCP_PADDING( temp_byte );
 707                         proto_tree_add_boolean( rtcp_tree, hf_rtcp_padding, tvb,
 708                             offset, 1, padding_set );
 709                         elem_count = RTCP_COUNT( temp_byte );
 710
 711                         switch ( packet_type ) {
 712                                 case RTCP_SR:
 713                                 case RTCP_RR:
 714                                         /* Receiver report count, 5 bits */
 715                                         proto_tree_add_uint( rtcp_tree, hf_rtcp_rc, tvb, offset, 1, elem_count );
 716                                         offset++;
 717                                         /* Packet type, 8 bits */
 718                                         proto_tree_add_item( rtcp_tree, hf_rtcp_pt, tvb, offset, 1, FALSE );
 719                                         offset++;
 720                                         /* Packet length in 32 bit words MINUS one, 16 bits */
 721                                         proto_tree_add_uint( rtcp_tree, hf_rtcp_length, tvb, offset, 2, tvb_get_ntohs( tvb, offset ) );
 722                                         offset += 2;
 723                                         /* Sender Synchronization source, 32 bits */
 724                                         proto_tree_add_uint( rtcp_tree, hf_rtcp_ssrc_sender, tvb, offset, 4, tvb_get_ntohl( tvb, offset ) );
 725                                         offset += 4;
 726
 727                                         if ( packet_type == RTCP_SR ) offset = dissect_rtcp_sr( tvb, offset, pinfo->fd, rtcp_tree, elem_count );
 728                                         else offset = dissect_rtcp_rr( tvb, offset, pinfo->fd, rtcp_tree, elem_count );
 729                                         break;
 730                                 case RTCP_SDES:
 731                                         /* Source count, 5 bits */
 732                                         proto_tree_add_uint( rtcp_tree, hf_rtcp_sc, tvb, offset, 1, elem_count );
 733                                         offset++;
 734                                         /* Packet type, 8 bits */
 735                                         proto_tree_add_item( rtcp_tree, hf_rtcp_pt, tvb, offset, 1, FALSE );
 736                                         offset++;
 737                                         /* Packet length in 32 bit words MINUS one, 16 bits */
 738                                         proto_tree_add_uint( rtcp_tree, hf_rtcp_length, tvb, offset, 2, tvb_get_ntohs( tvb, offset ) );
 739                                         offset += 2;
 740                                         offset = dissect_rtcp_sdes( tvb, offset, pinfo->fd, rtcp_tree, elem_count );
 741                                         break;
 742                                 case RTCP_BYE:
 743                                         /* Source count, 5 bits */
 744                                         proto_tree_add_uint( rtcp_tree, hf_rtcp_sc, tvb, offset, 1, elem_count );
 745                                         offset++;
 746                                         /* Packet type, 8 bits */
 747                                         proto_tree_add_item( rtcp_tree, hf_rtcp_pt, tvb, offset, 1, FALSE );
 748                                         offset++;
 749                                         /* Packet length in 32 bit words MINUS one, 16 bits */
 750                                         proto_tree_add_uint( rtcp_tree, hf_rtcp_length, tvb, offset, 2, tvb_get_ntohs( tvb, offset ) );
 751                                         offset += 2;
 752                                         offset = dissect_rtcp_bye( tvb, offset, pinfo->fd, rtcp_tree, elem_count );
 753                                         break;
 754                                 case RTCP_APP:
 755                                         /* Subtype, 5 bits */
 756                                         proto_tree_add_uint( rtcp_tree, hf_rtcp_subtype, tvb, offset, 1, elem_count );
 757                                         offset++;
 758                                         /* Packet type, 8 bits */
 759                                         proto_tree_add_item( rtcp_tree, hf_rtcp_pt, tvb, offset, 1, FALSE );
 760                                         offset++;
 761                                         /* Packet length in 32 bit words MINUS one, 16 bits */
 762                                         proto_tree_add_uint( rtcp_tree, hf_rtcp_length, tvb, offset, 2, tvb_get_ntohs( tvb, offset ) );
 763                                         offset += 2;
 764                                         dissect_rtcp_app( tvb, offset,
 765                                             pinfo->fd, rtcp_tree, padding_set,
 766                                             packet_length - 4 );
 767                                         break;
 768                                 case RTCP_FIR:
 769                                         dissect_rtcp_fir( tvb, offset, pinfo->fd, rtcp_tree );
 770                                         break;
 771                                 case RTCP_NACK:
 772                                         dissect_rtcp_nack( tvb, offset, pinfo->fd, rtcp_tree );
 773                                         break;
 774                                 default:
 775                                         /*
 776                                          * To prevent endless loops in case of an unknown message type
 777                                          * increase offset. Some time the while will end :-)
 778                                          */
 779                                         offset++;
 780                                         break;
 781                         }
 782                 }
 783                 /* If the padding bit is set, the last octet of the
 784                  * packet contains the length of the padding
 785                  * We only have to check for this at the end of the LAST RTCP message
 786                  */
 787                 if ( padding_set ) {
 788                         /* If everything went according to plan offset should now point to the
 789                          * first octet of the padding
 790                          */
 791                         proto_tree_add_item( rtcp_tree, hf_rtcp_padding_data, tvb, offset, tvb_length_remaining( tvb, offset) - 1, FALSE );
 792                         offset += tvb_length_remaining( tvb, offset) - 1;
 793                         proto_tree_add_item( rtcp_tree, hf_rtcp_padding_count, tvb, offset, 1, FALSE );
 794                 }
 795         }
 796 }
 797
 798 void
 799 proto_register_rtcp(void)
 800 {
 801         static hf_register_info hf[] =
 802         {
 803                 {
 804                         &hf_rtcp_version,
 805                         {
 806                                 "Version",
 807                                 "rtcp.version",
 808                                 FT_UINT8,
 809                                 BASE_DEC,
 810                                 VALS(rtcp_version_vals),
 811                                 0x0,
 812                                 ""
 813                         }
 814                 },
 815                 {
 816                         &hf_rtcp_padding,
 817                         {
 818                                 "Padding",
 819                                 "rtcp.padding",
 820                                 FT_BOOLEAN,
 821                                 BASE_NONE,
 822                                 NULL,
 823                                 0x0,
 824                                 ""
 825                         }
 826                 },
 827                 {
 828                         &hf_rtcp_rc,
 829                         {
 830                                 "Reception report count",
 831                                 "rtcp.rc",
 832                                 FT_UINT8,
 833                                 BASE_DEC,
 834                                 NULL,
 835                                 0x0,
 836                                 ""
 837                         }
 838                 },
 839                 {
 840                         &hf_rtcp_sc,
 841                         {
 842                                 "Source count",
 843                                 "rtcp.sc",
 844                                 FT_UINT8,
 845                                 BASE_DEC,
 846                                 NULL,
 847                                 0x0,
 848                                 ""
 849                         }
 850                 },
 851                 {
 852                         &hf_rtcp_pt,
 853                         {
 854                                 "Packet type",
 855                                 "rtcp.pt",
 856                                 FT_UINT8,
 857                                 BASE_DEC,
 858                                 VALS( rtcp_packet_type_vals ),
 859                                 0x0,
 860                                 ""
 861                         }
 862                 },
 863                 {
 864                         &hf_rtcp_length,
 865                         {
 866                                 "Length",
 867                                 "rtcp.length",
 868                                 FT_UINT16,
 869                                 BASE_DEC,
 870                                 NULL,
 871                                 0x0,
 872                                 ""
 873                         }
 874                 },
 875                 {
 876                         &hf_rtcp_ssrc_sender,
 877                         {
 878                                 "Sender SSRC",
 879                                 "rtcp.senderssrc",
 880                                 FT_UINT32,
 881                                 BASE_DEC,
 882                                 NULL,
 883                                 0x0,
 884                                 ""
 885                         }
 886                 },
 887                 {
 888                         &hf_rtcp_ntp,
 889                         {
 890                                 "NTP timestamp",
 891                                 "rtcp.timestamp.ntp",
 892                                 FT_STRING,
 893                                 BASE_NONE,
 894                                 NULL,
 895                                 0x0,
 896                                 ""
 897                         }
 898                 },
 899                 {
 900                         &hf_rtcp_rtp_timestamp,
 901                         {
 902                                 "RTP timestamp",
 903                                 "rtcp.timestamp.rtp",
 904                                 FT_UINT32,
 905                                 BASE_DEC,
 906                                 NULL,
 907                                 0x0,
 908                                 ""
 909                         }
 910                 },
 911                 {
 912                         &hf_rtcp_sender_pkt_cnt,
 913                         {
 914                                 "Sender's packet count",
 915                                 "rtcp.sender.packetcount",
 916                                 FT_UINT32,
 917                                 BASE_DEC,
 918                                 NULL,
 919                                 0x0,
 920                                 ""
 921                         }
 922                 },
 923                 {
 924                         &hf_rtcp_sender_oct_cnt,
 925                         {
 926                                 "Sender's octet count",
 927                                 "rtcp.sender.octetcount",
 928                                 FT_UINT32,
 929                                 BASE_DEC,
 930                                 NULL,
 931                                 0x0,
 932                                 ""
 933                         }
 934                 },
 935                 {
 936                         &hf_rtcp_ssrc_source,
 937                         {
 938                                 "Identifier",
 939                                 "rtcp.ssrc.identifier",
 940                                 FT_UINT32,
 941                                 BASE_DEC,
 942                                 NULL,
 943                                 0x0,
 944                                 ""
 945                         }
 946                 },
 947                 {
 948                         &hf_rtcp_ssrc_fraction,
 949                         {
 950                                 "Fraction lost",
 951                                 "rtcp.ssrc.fraction",
 952                                 FT_UINT8,
 953                                 BASE_DEC,
 954                                 NULL,
 955                                 0x0,
 956                                 ""
 957                         }
 958                 },
 959                 {
 960                         &hf_rtcp_ssrc_cum_nr,
 961                         {
 962                                 "Cumulative number of packets lost",
 963                                 "rtcp.ssrc.cum_nr",
 964                                 FT_UINT32,
 965                                 BASE_DEC,
 966                                 NULL,
 967                                 0x0,
 968                                 ""
 969                         }
 970                 },
 971                 {
 972                         &hf_rtcp_ssrc_ext_high_seq,
 973                         {
 974                                 "Extended highest sequence number received",
 975                                 "rtcp.ssrc.ext_high",
 976                                 FT_UINT32,
 977                                 BASE_DEC,
 978                                 NULL,
 979                                 0x0,
 980                                 ""
 981                         }
 982                 },
 983                 {
 984                         &hf_rtcp_ssrc_high_seq,
 985                         {
 986                                 "Highest sequence number received",
 987                                 "rtcp.ssrc.high_seq",
 988                                 FT_UINT16,
 989                                 BASE_DEC,
 990                                 NULL,
 991                                 0x0,
 992                                 ""
 993                         }
 994                 },
 995                 {
 996                         &hf_rtcp_ssrc_high_cycles,
 997                         {
 998                                 "Sequence number cycles count",
 999                                 "rtcp.ssrc.high_cycles",
1000                                 FT_UINT16,
1001                                 BASE_DEC,
1002                                 NULL,
1003                                 0x0,
1004                                 ""
1005                         }
1006                 },
1007                 {
1008                         &hf_rtcp_ssrc_jitter,
1009                         {
1010                                 "Interarrival jitter",
1011                                 "rtcp.ssrc.jitter",
1012                                 FT_UINT32,
1013                                 BASE_DEC,
1014                                 NULL,
1015                                 0x0,
1016                                 ""
1017                         }
1018                 },
1019                 {
1020                         &hf_rtcp_ssrc_lsr,
1021                         {
1022                                 "Last SR timestamp",
1023                                 "rtcp.ssrc.lsr",
1024                                 FT_UINT32,
1025                                 BASE_DEC,
1026                                 NULL,
1027                                 0x0,
1028                                 ""
1029                         }
1030                 },
1031                 {
1032                         &hf_rtcp_ssrc_dlsr,
1033                         {
1034                                 "Delay since last SR timestamp",
1035                                 "rtcp.ssrc.dlsr",
1036                                 FT_UINT32,
1037                                 BASE_DEC,
1038                                 NULL,
1039                                 0x0,
1040                                 ""
1041                         }
1042                 },
1043                 {
1044                         &hf_rtcp_ssrc_csrc,
1045                         {
1046                                 "SSRC / CSRC identifier",
1047                                 "rtcp.sdes.ssrc_csrc",
1048                                 FT_UINT32,
1049                                 BASE_DEC,
1050                                 NULL,
1051                                 0x0,
1052                                 ""
1053                         }
1054                 },
1055                 {
1056                         &hf_rtcp_ssrc_type,
1057                         {
1058                                 "Type",
1059                                 "rtcp.sdes.type",
1060                                 FT_UINT8,
1061                                 BASE_DEC,
1062                                 VALS( rtcp_sdes_type_vals ),
1063                                 0x0,
1064                                 ""
1065                         }
1066                 },
1067                 {
1068                         &hf_rtcp_ssrc_length,
1069                         {
1070                                 "Length",
1071                                 "rtcp.sdes.length",
1072                                 FT_UINT32,
1073                                 BASE_DEC,
1074                                 NULL,
1075                                 0x0,
1076                                 ""
1077                         }
1078                 },
1079                 {
1080                         &hf_rtcp_ssrc_text,
1081                         {
1082                                 "Text",
1083                                 "rtcp.sdes.text",
1084                                 FT_STRING,
1085                                 BASE_NONE,
1086                                 NULL,
1087                                 0x0,
1088                                 ""
1089                         }
1090                 },
1091                 {
1092                         &hf_rtcp_ssrc_prefix_len,
1093                         {
1094                                 "Prefix length",
1095                                 "rtcp.sdes.prefix.length",
1096                                 FT_UINT8,
1097                                 BASE_DEC,
1098                                 NULL,
1099                                 0x0,
1100                                 ""
1101                         }
1102                 },
1103                 {
1104                         &hf_rtcp_ssrc_prefix_string,
1105                         {
1106                                 "Prefix string",
1107                                 "rtcp.sdes.prefix.string",
1108                                 FT_STRING,
1109                                 BASE_NONE,
1110                                 NULL,
1111                                 0x0,
1112                                 ""
1113                         }
1114                 },
1115                 {
1116                         &hf_rtcp_subtype,
1117                         {
1118                                 "Subtype",
1119                                 "rtcp.app.subtype",
1120                                 FT_UINT8,
1121                                 BASE_DEC,
1122                                 NULL,
1123                                 0x0,
1124                                 ""
1125                         }
1126                 },
1127                 {
1128                         &hf_rtcp_name_ascii,
1129                         {
1130                                 "Name (ASCII)",
1131                                 "rtcp.app.name",
1132                                 FT_STRING,
1133                                 BASE_NONE,
1134                                 NULL,
1135                                 0x0,
1136                                 ""
1137                         }
1138                 },
1139                 {
1140                         &hf_rtcp_app_data,
1141                         {
1142                                 "Application specific data",
1143                                 "rtcp.app.data",
1144                                 FT_BYTES,
1145                                 BASE_NONE,
1146                                 NULL,
1147                                 0x0,
1148                                 ""
1149                         }
1150                 },
1151                 {
1152                         &hf_rtcp_fsn,
1153                         {
1154                                 "First sequence number",
1155                                 "rtcp.nack.fsn",
1156                                 FT_UINT16,
1157                                 BASE_DEC,
1158                                 NULL,
1159                                 0x0,
1160                                 ""
1161                         }
1162                 },
1163                 {
1164                         &hf_rtcp_blp,
1165                         {
1166                                 "Bitmask of following lost packets",
1167                                 "rtcp.nack.blp",
1168                                 FT_UINT16,
1169                                 BASE_DEC,
1170                                 NULL,
1171                                 0x0,
1172                                 ""
1173                         }
1174                 },
1175                 {
1176                         &hf_rtcp_padding_count,
1177                         {
1178                                 "Padding count",
1179                                 "rtcp.padding.count",
1180                                 FT_UINT8,
1181                                 BASE_DEC,
1182                                 NULL,
1183                                 0x0,
1184                                 ""
1185                         }
1186                 },
1187                 {
1188                         &hf_rtcp_padding_data,
1189                         {
1190                                 "Padding data",
1191                                 "rtcp.padding.data",
1192                                 FT_BYTES,
1193                                 BASE_NONE,
1194                                 NULL,
1195                                 0x0,
1196                                 ""
1197                         }
1198                 },
1199 };
1200
1201         static gint *ett[] =
1202         {
1203                 &ett_rtcp,
1204                 &ett_ssrc,
1205                 &ett_ssrc_item,
1206                 &ett_ssrc_ext_high,
1207                 &ett_sdes,
1208                 &ett_sdes_item,
1209         };
1210
1211
1212         proto_rtcp = proto_register_protocol("Real-time Transport Control Protocol",
1213             "RTCP", "rtcp");
1214         proto_register_field_array(proto_rtcp, hf, array_length(hf));
1215         proto_register_subtree_array(ett, array_length(ett));
1216
1217 #if 0
1218         register_init_routine( &rtcp_init );
1219 #endif
1220 }
1221
1222 void
1223 proto_reg_handoff_rtcp(void)
1224 {
1225         /*
1226          * Register this dissector as one that can be assigned to a
1227          * UDP conversation.
1228          */
1229         conv_dissector_add("udp", dissect_rtcp, proto_rtcp);
1230 }