packet-rtcp.c

   1 /* packet-rtcp.c
   2  *
   3  * $Id: packet-rtcp.c,v 1.28 2002/01/10 22:21:13 guy Exp $
   4  *
   5  * Routines for RTCP dissection
   6  * RTCP = Real-time Transport Control Protocol
   7  *
   8  * Copyright 2000, Philips Electronics N.V.
   9  * Written by Andreas Sikkema <andreas.sikkema@philips.com>
  10  *
  11  * Ethereal - Network traffic analyzer
  12  * By Gerald Combs <gerald@ethereal.com>
  13  * Copyright 1998 Gerald Combs
  14  *
  15  * This program is free software; you can redistribute it and/or
  16  * modify it under the terms of the GNU General Public License
  17  * as published by the Free Software Foundation; either version 2
  18  * of the License, or (at your option) any later version.
  19  *
  20  * This program is distributed in the hope that it will be useful,
  21  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  22  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  23  * GNU General Public License for more details.
  24  *
  25  * You should have received a copy of the GNU General Public License
  26  * along with this program; if not, write to the Free Software
  27  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  28  */
  29
  30 /*
  31  * This dissector tries to dissect the RTCP protocol according to Annex A
  32  * of ITU-T Recommendation H.225.0 (02/98) and RFC 1889
  33  * H.225.0 literally copies RFC 1889, but omitting a few sections.
  34  *
  35  * RTCP traffic is handled by an uneven UDP portnumber. This can be any
  36  * port number, but there is a registered port available, port 5005
  37  * See Annex B of ITU-T Recommendation H.225.0, section B.7
  38  *
  39  */
  40
  41
  42 #ifdef HAVE_CONFIG_H
  43 # include "config.h"
  44 #endif
  45
  46 #include <glib.h>
  47 #include "packet.h"
  48
  49 #ifdef HAVE_SYS_TYPES_H
  50 #  include <sys/types.h>
  51 #endif
  52
  53 #ifdef HAVE_NETINET_IN_H
  54 #  include <netinet/in.h>
  55 #endif
  56
  57 #include <stdio.h>
  58 #include <string.h>
  59
  60 #include "packet-rtcp.h"
  61 #if 0
  62 #include "packet-ntp.h"
  63 #endif
  64 #include "conversation.h"
  65
  66 /* Version is the first 2 bits of the first octet*/
  67 #define RTCP_VERSION(octet)     ((octet) >> 6)
  68
  69 /* Padding is the third bit; no need to shift, because true is any value
  70    other than 0! */
  71 #define RTCP_PADDING(octet)     ((octet) & 0x20)
  72
  73 /* Receiver/ Sender count is the 5 last bits  */
  74 #define RTCP_COUNT(octet)       ((octet) & 0x1F)
  75
  76 static const value_string rtcp_version_vals[] =
  77 {
  78         { 0, "Old VAT Version" },
  79         { 1, "First Draft Version" },
  80         { 2, "RFC 1889 Version" },
  81         { 0, NULL },
  82 };
  83
  84 /* RTCP packet types according to Section A.11.1 */
  85 #define RTCP_SR   200
  86 #define RTCP_RR   201
  87 #define RTCP_SDES 202
  88 #define RTCP_BYE  203
  89 #define RTCP_APP  204
  90 /* Supplemental H.261 specific RTCP packet types according to Section C.3.5 */
  91 #define RTCP_FIR  192
  92 #define RTCP_NACK 193
  93
  94 static const value_string rtcp_packet_type_vals[] =
  95 {
  96         { RTCP_SR,   "Sender Report" },
  97         { RTCP_RR,   "Receiver Report" },
  98         { RTCP_SDES, "Source description" },
  99         { RTCP_BYE,  "Goodbye" },
 100         { RTCP_APP,  "Application specific" },
 101         { RTCP_FIR,  "Full Intra-frame Request (H.261)" },
 102         { RTCP_NACK, "Negative Acknowledgement (H.261)" },
 103         { 0,         NULL },
 104 };
 105
 106 /* RTCP SDES types (Section A.11.2) */
 107 #define RTCP_SDES_END    0
 108 #define RTCP_SDES_CNAME  1
 109 #define RTCP_SDES_NAME   2
 110 #define RTCP_SDES_EMAIL  3
 111 #define RTCP_SDES_PHONE  4
 112 #define RTCP_SDES_LOC    5
 113 #define RTCP_SDES_TOOL   6
 114 #define RTCP_SDES_NOTE   7
 115 #define RTCP_SDES_PRIV   8
 116
 117 static const value_string rtcp_sdes_type_vals[] =
 118 {
 119         { RTCP_SDES_END,   "END" },
 120         { RTCP_SDES_CNAME, "CNAME (user and domain)" },
 121         { RTCP_SDES_NAME,  "NAME (common name)" },
 122         { RTCP_SDES_EMAIL, "EMAIL (e-mail address)" },
 123         { RTCP_SDES_PHONE, "PHONE (phone number)" },
 124         { RTCP_SDES_LOC,   "LOC (geographic location)" },
 125         { RTCP_SDES_TOOL,  "TOOL (name/version of source app)" },
 126         { RTCP_SDES_NOTE,  "NOTE (note about source)" },
 127         { RTCP_SDES_PRIV,  "PRIV (private extensions)" },
 128         { 0,               NULL },
 129 };
 130
 131 /* RTCP header fields                   */
 132 static int proto_rtcp                = -1;
 133 static int hf_rtcp_version           = -1;
 134 static int hf_rtcp_padding           = -1;
 135 static int hf_rtcp_rc                = -1;
 136 static int hf_rtcp_sc                = -1;
 137 static int hf_rtcp_pt                = -1;
 138 static int hf_rtcp_length            = -1;
 139 static int hf_rtcp_ssrc_sender       = -1;
 140 static int hf_rtcp_ntp               = -1;
 141 static int hf_rtcp_rtp_timestamp     = -1;
 142 static int hf_rtcp_sender_pkt_cnt    = -1;
 143 static int hf_rtcp_sender_oct_cnt    = -1;
 144 static int hf_rtcp_ssrc_source       = -1;
 145 static int hf_rtcp_ssrc_fraction     = -1;
 146 static int hf_rtcp_ssrc_cum_nr       = -1;
 147 /* First the 32 bit number, then the split
 148  * up 16 bit values */
 149 /* These two are added to a subtree */
 150 static int hf_rtcp_ssrc_ext_high_seq = -1;
 151 static int hf_rtcp_ssrc_high_seq     = -1;
 152 static int hf_rtcp_ssrc_high_cycles  = -1;
 153 static int hf_rtcp_ssrc_jitter       = -1;
 154 static int hf_rtcp_ssrc_lsr          = -1;
 155 static int hf_rtcp_ssrc_dlsr         = -1;
 156 static int hf_rtcp_ssrc_csrc         = -1;
 157 static int hf_rtcp_ssrc_type         = -1;
 158 static int hf_rtcp_ssrc_length       = -1;
 159 static int hf_rtcp_ssrc_text         = -1;
 160 static int hf_rtcp_ssrc_prefix_len   = -1;
 161 static int hf_rtcp_ssrc_prefix_string= -1;
 162 static int hf_rtcp_subtype           = -1;
 163 static int hf_rtcp_name_ascii        = -1;
 164 static int hf_rtcp_app_data          = -1;
 165 static int hf_rtcp_fsn               = -1;
 166 static int hf_rtcp_blp               = -1;
 167 static int hf_rtcp_padding_count     = -1;
 168 static int hf_rtcp_padding_data      = -1;
 169
 170 /* RTCP fields defining a sub tree */
 171 static gint ett_rtcp           = -1;
 172 static gint ett_ssrc           = -1;
 173 static gint ett_ssrc_item      = -1;
 174 static gint ett_ssrc_ext_high  = -1;
 175 static gint ett_sdes           = -1;
 176 static gint ett_sdes_item      = -1;
 177
 178 static address fake_addr;
 179 static int heur_init = FALSE;
 180
 181 static gboolean dissect_rtcp_heur( tvbuff_t *tvb, packet_info *pinfo,
 182     proto_tree *tree );
 183 static void dissect_rtcp( tvbuff_t *tvb, packet_info *pinfo,
 184      proto_tree *tree );
 185
 186 void rtcp_add_address( packet_info *pinfo, const unsigned char* ip_addr,
 187     int prt )
 188 {
 189         address src_addr;
 190         conversation_t* pconv;
 191
 192         /*
 193          * If this isn't the first time this packet has been processed,
 194          * we've already done this work, so we don't need to do it
 195          * again.
 196          */
 197         if (pinfo->fd->flags.visited)
 198                 return;
 199
 200         src_addr.type = AT_IPv4;
 201         src_addr.len = 4;
 202         src_addr.data = ip_addr;
 203
 204         /*
 205          * The first time the function is called let the udp dissector
 206          * know that we're interested in traffic
 207          */
 208         if ( ! heur_init ) {
 209                 heur_dissector_add( "udp", dissect_rtcp_heur, proto_rtcp );
 210                 heur_init = TRUE;
 211         }
 212
 213         /*
 214          * Check if the ip address and port combination is not
 215          * already registered
 216          */
 217         pconv = find_conversation( &src_addr, &fake_addr, PT_UDP, prt, 0, 0 );
 218
 219         /*
 220          * If not, add
 221          * XXX - use wildcard address and port B?
 222          */
 223         if ( ! pconv ) {
 224                 pconv = conversation_new( &src_addr, &fake_addr, PT_UDP,
 225                     (guint32) prt, (guint32) 0, 0 );
 226                 conversation_add_proto_data(pconv, proto_rtcp, NULL);
 227         }
 228
 229 }
 230
 231 #if 0
 232 static void rtcp_init( void )
 233 {
 234         unsigned char* tmp_data;
 235         int i;
 236
 237         /* Create a fake adddress... */
 238         fake_addr.type = AT_IPv4;
 239         fake_addr.len = 4;
 240
 241         tmp_data = malloc( fake_addr.len );
 242         for ( i = 0; i < fake_addr.len; i++) {
 243                 tmp_data[i] = 0;
 244         }
 245         fake_addr.data = tmp_data;
 246 }
 247 #endif
 248
 249 static gboolean
 250 dissect_rtcp_heur( tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree )
 251 {
 252         conversation_t* pconv;
 253
 254         /* This is a heuristic dissector, which means we get all the UDP
 255          * traffic not sent to a known dissector and not claimed by
 256          * a heuristic dissector called before us!
 257          * So we first check if the frame is really meant for us.
 258          */
 259         if ( ( pconv = find_conversation( &pinfo->src, &fake_addr, pinfo->ptype,
 260             pinfo->srcport, 0, 0 ) ) == NULL ) {
 261                 /*
 262                  * The source ip:port combination was not what we were
 263                  * looking for, check the destination
 264                  */
 265                 if ( ( pconv = find_conversation( &pinfo->dst, &fake_addr,
 266                     pinfo->ptype, pinfo->destport, 0, 0 ) ) == NULL ) {
 267                         return FALSE;
 268                 }
 269         }
 270
 271
 272         /*
 273          * An RTCP conversation always has a data item for RTCP.
 274          * (Its existence is sufficient to indicate that this is an RTCP
 275          * conversation.)
 276          */
 277         if (conversation_get_proto_data(pconv, proto_rtcp) == NULL)
 278                 return FALSE;
 279
 280         /*
 281          * The message is a valid RTCP message!
 282          */
 283         dissect_rtcp( tvb, pinfo, tree );
 284
 285         return TRUE;
 286 }
 287
 288
 289 static int
 290 dissect_rtcp_nack( tvbuff_t *tvb, int offset, frame_data *fd, proto_tree *tree )
 291 {
 292         /* Packet type = FIR (H261) */
 293         proto_tree_add_uint( tree, hf_rtcp_rc, tvb, offset, 1, tvb_get_guint8( tvb, offset ) & 31 );
 294         offset++;
 295         /* Packet type, 8 bits  = APP */
 296         proto_tree_add_item( tree, hf_rtcp_pt, tvb, offset, 1, FALSE );
 297         offset++;
 298
 299         /* Packet length in 32 bit words minus one */
 300         proto_tree_add_uint( tree, hf_rtcp_length, tvb, offset, 2, tvb_get_ntohs( tvb, offset ) );
 301         offset += 2;
 302
 303         /* SSRC  */
 304         proto_tree_add_uint( tree, hf_rtcp_ssrc_source, tvb, offset, 4, tvb_get_ntohl( tvb, offset ) );
 305         offset += 4;
 306
 307         /* FSN, 16 bits */
 308         proto_tree_add_uint( tree, hf_rtcp_fsn, tvb, offset, 2, tvb_get_ntohs( tvb, offset ) );
 309         offset += 2;
 310
 311         /* BLP, 16 bits */
 312         proto_tree_add_uint( tree, hf_rtcp_blp, tvb, offset, 2, tvb_get_ntohs( tvb, offset ) );
 313         offset += 2;
 314
 315         return offset;
 316 }
 317
 318 static int
 319 dissect_rtcp_fir( tvbuff_t *tvb, int offset, frame_data *fd, proto_tree *tree )
 320 {
 321         /* Packet type = FIR (H261) */
 322         proto_tree_add_uint( tree, hf_rtcp_rc, tvb, offset, 1, tvb_get_guint8( tvb, offset ) & 31 );
 323         offset++;
 324         /* Packet type, 8 bits  = APP */
 325         proto_tree_add_item( tree, hf_rtcp_pt, tvb, offset, 1, FALSE );
 326         offset++;
 327
 328         /* Packet length in 32 bit words minus one */
 329         proto_tree_add_uint( tree, hf_rtcp_length, tvb, offset, 2, tvb_get_ntohs( tvb, offset ) );
 330         offset += 2;
 331
 332         /* SSRC  */
 333         proto_tree_add_uint( tree, hf_rtcp_ssrc_source, tvb, offset, 4, tvb_get_ntohl( tvb, offset ) );
 334         offset += 4;
 335
 336         return offset;
 337 }
 338
 339 static int
 340 dissect_rtcp_app( tvbuff_t *tvb, int offset, frame_data *fd, proto_tree *tree,
 341     unsigned int padding, unsigned int packet_len )
 342 {
 343         unsigned int counter = 0;
 344         char ascii_name[5];
 345
 346         /* SSRC / CSRC */
 347         proto_tree_add_uint( tree, hf_rtcp_ssrc_source, tvb, offset, 4, tvb_get_ntohl( tvb, offset ) );
 348         offset += 4;
 349         packet_len -= 4;
 350
 351         /* Name (ASCII) */
 352         for( counter = 0; counter < 4; counter++ )
 353             ascii_name[ counter ] = tvb_get_guint8( tvb, offset + counter );
 354         /* strncpy( ascii_name, pd + offset, 4 ); */
 355         ascii_name[4] = '\0';
 356         proto_tree_add_string( tree, hf_rtcp_name_ascii, tvb, offset, 4,
 357             ascii_name );
 358         offset += 4;
 359         packet_len -= 4;
 360
 361         /* Applications specific data */
 362         if ( padding ) {
 363                 /* If there's padding present, we have to remove that from the data part
 364                  * The last octet of the packet contains the length of the padding
 365                  */
 366                 packet_len -= tvb_get_guint8( tvb, offset + packet_len - 1 );
 367         }
 368         proto_tree_add_item( tree, hf_rtcp_app_data, tvb, offset, packet_len, FALSE );
 369         offset += packet_len;
 370
 371         return offset;
 372 }
 373
 374 static int
 375 dissect_rtcp_bye( tvbuff_t *tvb, int offset, frame_data *fd, proto_tree *tree,
 376     unsigned int count )
 377 {
 378         unsigned int chunk          = 1;
 379         unsigned int reason_length  = 0;
 380         unsigned int counter = 0;
 381         char* reason_text = NULL;
 382
 383         while ( chunk <= count ) {
 384                 /* source identifier, 32 bits */
 385                 proto_tree_add_uint( tree, hf_rtcp_ssrc_source, tvb, offset, 4, tvb_get_ntohl( tvb, offset ) );
 386                 offset += 4;
 387         }
 388
 389         if ( tvb_reported_length_remaining( tvb, offset ) > 0 ) {
 390                 /* Bye reason consists of an 8 bit length l and a string with length l */
 391                 reason_length = tvb_get_guint8( tvb, offset );
 392                 proto_tree_add_item( tree, hf_rtcp_ssrc_length, tvb, offset, 1, FALSE );
 393                 offset++;
 394
 395                 reason_text = ( char* ) malloc( reason_length + 1 );
 396                 for ( counter = 0; counter < reason_length; counter++ ) reason_text[ counter ] = tvb_get_guint8( tvb, offset + counter );
 397                 /* strncpy( reason_text, pd + offset, reason_length ); */
 398                 reason_text[ reason_length ] = '\0';
 399                 proto_tree_add_string( tree, hf_rtcp_ssrc_text, tvb, offset, reason_length, reason_text );
 400                 free( reason_text );
 401                 offset += reason_length;
 402         }
 403
 404         return offset;
 405
 406 }
 407
 408 static int
 409 dissect_rtcp_sdes( tvbuff_t *tvb, int offset, frame_data *fd, proto_tree *tree,
 410     unsigned int count )
 411 {
 412         unsigned int chunk          = 1;
 413         proto_item *sdes_item;
 414         proto_tree *sdes_tree;
 415         proto_tree *sdes_item_tree;
 416         proto_item *ti;
 417         int start_offset;
 418         int items_start_offset;
 419         guint32 ssrc;
 420         unsigned int item_len       = 0;
 421         unsigned int sdes_type      = 0;
 422         unsigned int counter        = 0;
 423         unsigned int prefix_len     = 0;
 424         char *prefix_string = NULL;
 425
 426         while ( chunk <= count ) {
 427                 /* Create a subtree for this chunk; we don't yet know
 428                    the length. */
 429                 start_offset = offset;
 430
 431                 ssrc = tvb_get_ntohl( tvb, offset );
 432                 sdes_item = proto_tree_add_text(tree, tvb, offset, 0,
 433                     "Chunk %u, SSRC/CSRC %u", chunk, ssrc);
 434                 sdes_tree = proto_item_add_subtree( sdes_item, ett_sdes );
 435
 436                 /* SSRC_n source identifier, 32 bits */
 437                 proto_tree_add_uint( sdes_tree, hf_rtcp_ssrc_source, tvb, offset, 4, ssrc );
 438                 offset += 4;
 439
 440                 /* Create a subtree for the SDES items; we don't yet know
 441                    the length */
 442                 items_start_offset = offset;
 443                 ti = proto_tree_add_text(sdes_tree, tvb, offset, 0,
 444                     "SDES items" );
 445                 sdes_item_tree = proto_item_add_subtree( ti, ett_sdes_item );
 446
 447                 /*
 448                  * Not every message is ended with "null" bytes, so check for
 449                  * end of frame instead.
 450                  */
 451                 while ( ( tvb_reported_length_remaining( tvb, offset ) > 0 )
 452                     && ( tvb_get_guint8( tvb, offset ) != RTCP_SDES_END ) ) {
 453                         /* ID, 8 bits */
 454                         sdes_type = tvb_get_guint8( tvb, offset );
 455                         proto_tree_add_item( sdes_item_tree, hf_rtcp_ssrc_type, tvb, offset, 1, FALSE );
 456                         offset++;
 457
 458                         /* Item length, 8 bits */
 459                         item_len = tvb_get_guint8( tvb, offset );
 460                         proto_tree_add_item( sdes_item_tree, hf_rtcp_ssrc_length, tvb, offset, 1, FALSE );
 461                         offset++;
 462
 463                         if ( sdes_type == RTCP_SDES_PRIV ) {
 464                                 /* PRIV adds two items between the SDES length
 465                                  * and value - an 8 bit length giving the
 466                                  * length of a "prefix string", and the string.
 467                                  */
 468                                 prefix_len = tvb_get_guint8( tvb, offset );
 469                                 proto_tree_add_item( sdes_item_tree, hf_rtcp_ssrc_prefix_len, tvb, offset, 1, FALSE );
 470                                 offset++;
 471
 472                                 prefix_string = ( char * ) malloc( prefix_len + 1 );
 473                                 for ( counter = 0; counter < prefix_len; counter++ )
 474                                         prefix_string[ counter ] =
 475                                             tvb_get_guint8( tvb, offset + counter );
 476                                 /* strncpy( prefix_string, pd + offset, prefix_len ); */
 477                                 prefix_string[ prefix_len ] = '\0';
 478                                 proto_tree_add_string( sdes_item_tree, hf_rtcp_ssrc_prefix_string, tvb, offset, prefix_len, prefix_string );
 479                                 free( prefix_string );
 480                                 offset += prefix_len;
 481                         }
 482                         prefix_string = ( char * ) malloc( item_len + 1 );
 483                         for ( counter = 0; counter < item_len; counter++ )
 484                             prefix_string[ counter ] =
 485                                 tvb_get_guint8( tvb, offset + counter );
 486                         /* strncpy( prefix_string, pd + offset, item_len ); */
 487                         prefix_string[ item_len] = 0;
 488                         proto_tree_add_string( sdes_item_tree, hf_rtcp_ssrc_text, tvb, offset, item_len, prefix_string );
 489                         free( prefix_string );
 490                         offset += item_len;
 491                 }
 492
 493                 /* Set the length of the items subtree. */
 494                 proto_item_set_len(ti, offset - items_start_offset);
 495
 496                 /* 32 bits = 4 bytes, so.....
 497                  * If offset % 4 != 0, we divide offset by 4, add one and then
 498                  * multiply by 4 again to reach the boundary
 499                  */
 500                 if ( offset % 4 != 0 )
 501                         offset = ((offset / 4) + 1 ) * 4;
 502
 503                 /* Set the length of this chunk. */
 504                 proto_item_set_len(sdes_item, offset - start_offset);
 505
 506                 chunk++;
 507         }
 508
 509
 510         return offset;
 511 }
 512
 513 static int
 514 dissect_rtcp_rr( tvbuff_t *tvb, int offset, frame_data *fd, proto_tree *tree,
 515     unsigned int count )
 516 {
 517         unsigned int counter = 1;
 518         proto_tree *ssrc_tree = (proto_tree*) NULL;
 519         proto_tree *ssrc_sub_tree = (proto_tree*) NULL;
 520         proto_tree *high_sec_tree = (proto_tree*) NULL;
 521         proto_item *ti = (proto_item*) NULL;
 522         guint8 rr_flt;
 523         unsigned int cum_nr = 0;
 524
 525         while ( counter <= count ) {
 526                 /* Create a new subtree for a length of 24 bytes */
 527                 ti = proto_tree_add_text(tree, tvb, offset, 24,
 528                     "Source %u", counter );
 529                 ssrc_tree = proto_item_add_subtree( ti, ett_ssrc );
 530
 531                 /* SSRC_n source identifier, 32 bits */
 532                 proto_tree_add_uint( ssrc_tree, hf_rtcp_ssrc_source, tvb, offset, 4, tvb_get_ntohl( tvb, offset ) );
 533                 offset += 4;
 534
 535                 ti = proto_tree_add_text(ssrc_tree, tvb, offset, 20, "SSRC contents" );
 536                 ssrc_sub_tree = proto_item_add_subtree( ti, ett_ssrc_item );
 537
 538                 /* Fraction lost, 8bits */
 539                 rr_flt = tvb_get_guint8( tvb, offset );
 540                 proto_tree_add_uint_format( ssrc_sub_tree, hf_rtcp_ssrc_fraction, tvb,
 541                     offset, 1, rr_flt, "Fraction lost: %u / 256", rr_flt );
 542                 offset++;
 543
 544                 /* Cumulative number of packets lost, 24 bits */
 545                 cum_nr = tvb_get_ntohl( tvb, offset ) >> 8;
 546                 proto_tree_add_uint( ssrc_sub_tree, hf_rtcp_ssrc_cum_nr, tvb,
 547                     offset, 3, cum_nr );
 548                 offset += 3;
 549
 550                 /* Extended highest sequence nr received, 32 bits
 551                  * Just for the sake of it, let's add another subtree
 552                  * because this might be a little clearer
 553                  */
 554                 ti = proto_tree_add_uint( ssrc_tree, hf_rtcp_ssrc_ext_high_seq,
 555                     tvb, offset, 4, tvb_get_ntohl( tvb, offset ) );
 556                 high_sec_tree = proto_item_add_subtree( ti, ett_ssrc_ext_high );
 557                 /* Sequence number cycles */
 558                 proto_tree_add_uint( high_sec_tree, hf_rtcp_ssrc_high_cycles,
 559                     tvb, offset, 2, tvb_get_ntohs( tvb, offset ) );
 560                 offset += 2;
 561                 /* highest sequence number received */
 562                 proto_tree_add_uint( high_sec_tree, hf_rtcp_ssrc_high_seq,
 563                     tvb, offset, 2, tvb_get_ntohs( tvb, offset ) );
 564                 offset += 2;
 565
 566                 /* Interarrival jitter */
 567                 proto_tree_add_uint( ssrc_tree, hf_rtcp_ssrc_jitter, tvb,
 568                     offset, 4, tvb_get_ntohl( tvb, offset ) );
 569                 offset += 4;
 570
 571                 /* Last SR timestamp */
 572                 proto_tree_add_uint( ssrc_tree, hf_rtcp_ssrc_lsr, tvb,
 573                     offset, 4, tvb_get_ntohl( tvb, offset ) );
 574                 offset += 4;
 575
 576                 /* Delay since last SR timestamp */
 577                 proto_tree_add_uint( ssrc_tree, hf_rtcp_ssrc_dlsr, tvb,
 578                     offset, 4, tvb_get_ntohl( tvb, offset ) );
 579                 offset += 4;
 580                 counter++;
 581         }
 582
 583         return offset;
 584 }
 585
 586 static int
 587 dissect_rtcp_sr( tvbuff_t *tvb, int offset, frame_data *fd, proto_tree *tree,
 588     unsigned int count )
 589 {
 590 #if 0
 591         gchar buff[ NTP_TS_SIZE ];
 592         char* ptime = tvb_get_ptr( tvb, offset, 8 );
 593
 594         /* Retreive the NTP timestamp. Using the NTP dissector for this */
 595         ntp_fmt_ts( ptime, buff );
 596         proto_tree_add_string_format( tree, hf_rtcp_ntp, tvb, offset, 8, ( const char* ) &buff, "NTP timestamp: %s", &buff );
 597         free( ptime ); ??????????????????????????????????????????????????????????????????
 598         offset += 8;
 599 #else
 600         /*
 601          * XXX - RFC 1889 says this is an NTP timestamp, but that appears
 602          * not to be the case.
 603          */
 604         proto_tree_add_text(tree, tvb, offset, 4, "Timestamp, MSW: %u",
 605                 tvb_get_ntohl(tvb, offset));
 606         offset += 4;
 607         proto_tree_add_text(tree, tvb, offset, 4, "Timestamp, LSW: %u",
 608                 tvb_get_ntohl(tvb, offset));
 609         offset += 4;
 610 #endif
 611         /* RTP timestamp, 32 bits */
 612         proto_tree_add_uint( tree, hf_rtcp_rtp_timestamp, tvb, offset, 4, tvb_get_ntohl( tvb, offset ) );
 613         offset += 4;
 614         /* Sender's packet count, 32 bits */
 615         proto_tree_add_uint( tree, hf_rtcp_sender_pkt_cnt, tvb, offset, 4, tvb_get_ntohl( tvb, offset ) );
 616         offset += 4;
 617         /* Sender's octet count, 32 bits */
 618         proto_tree_add_uint( tree, hf_rtcp_sender_oct_cnt, tvb, offset, 4, tvb_get_ntohl( tvb, offset ) );
 619         offset += 4;
 620
 621         /* The rest of the packet is equal to the RR packet */
 622         if ( count != 0 )
 623                 offset = dissect_rtcp_rr( tvb, offset, fd, tree, count );
 624
 625         return offset;
 626 }
 627
 628 static void
 629 dissect_rtcp( tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree )
 630 {
 631         proto_item *ti           = NULL;
 632         proto_tree *rtcp_tree    = NULL;
 633         unsigned int temp_byte   = 0;
 634         unsigned int padding_set = 0;
 635         unsigned int elem_count  = 0;
 636         unsigned int packet_type = 0;
 637         unsigned int offset      = 0;
 638         guint16 packet_length    = 0;
 639
 640         if ( check_col( pinfo->cinfo, COL_PROTOCOL ) )   {
 641                 col_set_str( pinfo->cinfo, COL_PROTOCOL, "RTCP" );
 642         }
 643
 644         if ( check_col( pinfo->cinfo, COL_INFO) ) {
 645                 /* The second octet contains the packet type */
 646                 /* switch ( pd[ offset + 1 ] ) { */
 647                 switch ( tvb_get_guint8( tvb, 1 ) ) {
 648                         case RTCP_SR:
 649                                 col_set_str( pinfo->cinfo, COL_INFO, "Sender Report");
 650                                 break;
 651                         case RTCP_RR:
 652                                 col_set_str( pinfo->cinfo, COL_INFO, "Receiver Report");
 653                                 break;
 654                         case RTCP_SDES:
 655                                 col_set_str( pinfo->cinfo, COL_INFO, "Source Description");
 656                                 break;
 657                         case RTCP_BYE:
 658                                 col_set_str( pinfo->cinfo, COL_INFO, "Goodbye");
 659                                 break;
 660                         case RTCP_APP:
 661                                 col_set_str( pinfo->cinfo, COL_INFO, "Application defined");
 662                                 break;
 663                         case RTCP_FIR:
 664                                 col_set_str( pinfo->cinfo, COL_INFO, "Full Intra-frame Request (H.261)");
 665                                 break;
 666                         case RTCP_NACK:
 667                                 col_set_str( pinfo->cinfo, COL_INFO, "Negative Acknowledgement (H.261)");
 668                                 break;
 669                         default:
 670                                 col_set_str( pinfo->cinfo, COL_INFO, "Unknown packet type");
 671                                 break;
 672                 }
 673         }
 674
 675         if ( tree ) {
 676
 677                 /*
 678                  * Check if there are at least 4 bytes left in the frame,
 679                  * the last 16 bits of those is the length of the current
 680                  * RTCP message. The last compound message contains padding,
 681                  * that enables us to break from the while loop.
 682                  */
 683                 while ( tvb_bytes_exist( tvb, offset, 4) ) {
 684                         /*
 685                          * First retreive the packet_type
 686                          */
 687                         packet_type = tvb_get_guint8( tvb, offset + 1 );
 688
 689                         /*
 690                          * Check if it's a valid type
 691                          */
 692                         if ( ( packet_type < 192 ) || ( packet_type >  204 ) )
 693                                 break;
 694
 695                         /*
 696                          * get the packet-length for the complete RTCP packet
 697                          */
 698                         packet_length = ( tvb_get_ntohs( tvb, offset + 2 ) + 1 ) * 4;
 699
 700                         ti = proto_tree_add_item(tree, proto_rtcp, tvb, offset, packet_length, FALSE );
 701                         rtcp_tree = proto_item_add_subtree( ti, ett_rtcp );
 702
 703                         temp_byte = tvb_get_guint8( tvb, offset );
 704
 705                         proto_tree_add_uint( rtcp_tree, hf_rtcp_version, tvb,
 706                             offset, 1, RTCP_VERSION( temp_byte ) );
 707                         padding_set = RTCP_PADDING( temp_byte );
 708                         proto_tree_add_boolean( rtcp_tree, hf_rtcp_padding, tvb,
 709                             offset, 1, padding_set );
 710                         elem_count = RTCP_COUNT( temp_byte );
 711
 712                         switch ( packet_type ) {
 713                                 case RTCP_SR:
 714                                 case RTCP_RR:
 715                                         /* Receiver report count, 5 bits */
 716                                         proto_tree_add_uint( rtcp_tree, hf_rtcp_rc, tvb, offset, 1, elem_count );
 717                                         offset++;
 718                                         /* Packet type, 8 bits */
 719                                         proto_tree_add_item( rtcp_tree, hf_rtcp_pt, tvb, offset, 1, FALSE );
 720                                         offset++;
 721                                         /* Packet length in 32 bit words MINUS one, 16 bits */
 722                                         proto_tree_add_uint( rtcp_tree, hf_rtcp_length, tvb, offset, 2, tvb_get_ntohs( tvb, offset ) );
 723                                         offset += 2;
 724                                         /* Sender Synchronization source, 32 bits */
 725                                         proto_tree_add_uint( rtcp_tree, hf_rtcp_ssrc_sender, tvb, offset, 4, tvb_get_ntohl( tvb, offset ) );
 726                                         offset += 4;
 727
 728                                         if ( packet_type == RTCP_SR ) offset = dissect_rtcp_sr( tvb, offset, pinfo->fd, rtcp_tree, elem_count );
 729                                         else offset = dissect_rtcp_rr( tvb, offset, pinfo->fd, rtcp_tree, elem_count );
 730                                         break;
 731                                 case RTCP_SDES:
 732                                         /* Source count, 5 bits */
 733                                         proto_tree_add_uint( rtcp_tree, hf_rtcp_sc, tvb, offset, 1, elem_count );
 734                                         offset++;
 735                                         /* Packet type, 8 bits */
 736                                         proto_tree_add_item( rtcp_tree, hf_rtcp_pt, tvb, offset, 1, FALSE );
 737                                         offset++;
 738                                         /* Packet length in 32 bit words MINUS one, 16 bits */
 739                                         proto_tree_add_uint( rtcp_tree, hf_rtcp_length, tvb, offset, 2, tvb_get_ntohs( tvb, offset ) );
 740                                         offset += 2;
 741                                         offset = dissect_rtcp_sdes( tvb, offset, pinfo->fd, rtcp_tree, elem_count );
 742                                         break;
 743                                 case RTCP_BYE:
 744                                         /* Source count, 5 bits */
 745                                         proto_tree_add_uint( rtcp_tree, hf_rtcp_sc, tvb, offset, 1, elem_count );
 746                                         offset++;
 747                                         /* Packet type, 8 bits */
 748                                         proto_tree_add_item( rtcp_tree, hf_rtcp_pt, tvb, offset, 1, FALSE );
 749                                         offset++;
 750                                         /* Packet length in 32 bit words MINUS one, 16 bits */
 751                                         proto_tree_add_uint( rtcp_tree, hf_rtcp_length, tvb, offset, 2, tvb_get_ntohs( tvb, offset ) );
 752                                         offset += 2;
 753                                         offset = dissect_rtcp_bye( tvb, offset, pinfo->fd, rtcp_tree, elem_count );
 754                                         break;
 755                                 case RTCP_APP:
 756                                         /* Subtype, 5 bits */
 757                                         proto_tree_add_uint( rtcp_tree, hf_rtcp_subtype, tvb, offset, 1, elem_count );
 758                                         offset++;
 759                                         /* Packet type, 8 bits */
 760                                         proto_tree_add_item( rtcp_tree, hf_rtcp_pt, tvb, offset, 1, FALSE );
 761                                         offset++;
 762                                         /* Packet length in 32 bit words MINUS one, 16 bits */
 763                                         proto_tree_add_uint( rtcp_tree, hf_rtcp_length, tvb, offset, 2, tvb_get_ntohs( tvb, offset ) );
 764                                         offset += 2;
 765                                         offset = dissect_rtcp_app( tvb, offset,
 766                                             pinfo->fd, rtcp_tree, padding_set,
 767                                             packet_length - 4 );
 768                                         break;
 769                                 case RTCP_FIR:
 770                                         offset = dissect_rtcp_fir( tvb, offset, pinfo->fd, rtcp_tree );
 771                                         break;
 772                                 case RTCP_NACK:
 773                                         offset = dissect_rtcp_nack( tvb, offset, pinfo->fd, rtcp_tree );
 774                                         break;
 775                                 default:
 776                                         /*
 777                                          * To prevent endless loops in case of an unknown message type
 778                                          * increase offset. Some time the while will end :-)
 779                                          */
 780                                         offset++;
 781                                         break;
 782                         }
 783                 }
 784                 /* If the padding bit is set, the last octet of the
 785                  * packet contains the length of the padding
 786                  * We only have to check for this at the end of the LAST RTCP message
 787                  */
 788                 if ( padding_set ) {
 789                         /* If everything went according to plan offset should now point to the
 790                          * first octet of the padding
 791                          */
 792                         proto_tree_add_item( rtcp_tree, hf_rtcp_padding_data, tvb, offset, tvb_length_remaining( tvb, offset) - 1, FALSE );
 793                         offset += tvb_length_remaining( tvb, offset) - 1;
 794                         proto_tree_add_item( rtcp_tree, hf_rtcp_padding_count, tvb, offset, 1, FALSE );
 795                 }
 796         }
 797 }
 798
 799 void
 800 proto_register_rtcp(void)
 801 {
 802         static hf_register_info hf[] =
 803         {
 804                 {
 805                         &hf_rtcp_version,
 806                         {
 807                                 "Version",
 808                                 "rtcp.version",
 809                                 FT_UINT8,
 810                                 BASE_DEC,
 811                                 VALS(rtcp_version_vals),
 812                                 0x0,
 813                                 "", HFILL
 814                         }
 815                 },
 816                 {
 817                         &hf_rtcp_padding,
 818                         {
 819                                 "Padding",
 820                                 "rtcp.padding",
 821                                 FT_BOOLEAN,
 822                                 BASE_NONE,
 823                                 NULL,
 824                                 0x0,
 825                                 "", HFILL
 826                         }
 827                 },
 828                 {
 829                         &hf_rtcp_rc,
 830                         {
 831                                 "Reception report count",
 832                                 "rtcp.rc",
 833                                 FT_UINT8,
 834                                 BASE_DEC,
 835                                 NULL,
 836                                 0x0,
 837                                 "", HFILL
 838                         }
 839                 },
 840                 {
 841                         &hf_rtcp_sc,
 842                         {
 843                                 "Source count",
 844                                 "rtcp.sc",
 845                                 FT_UINT8,
 846                                 BASE_DEC,
 847                                 NULL,
 848                                 0x0,
 849                                 "", HFILL
 850                         }
 851                 },
 852                 {
 853                         &hf_rtcp_pt,
 854                         {
 855                                 "Packet type",
 856                                 "rtcp.pt",
 857                                 FT_UINT8,
 858                                 BASE_DEC,
 859                                 VALS( rtcp_packet_type_vals ),
 860                                 0x0,
 861                                 "", HFILL
 862                         }
 863                 },
 864                 {
 865                         &hf_rtcp_length,
 866                         {
 867                                 "Length",
 868                                 "rtcp.length",
 869                                 FT_UINT16,
 870                                 BASE_DEC,
 871                                 NULL,
 872                                 0x0,
 873                                 "", HFILL
 874                         }
 875                 },
 876                 {
 877                         &hf_rtcp_ssrc_sender,
 878                         {
 879                                 "Sender SSRC",
 880                                 "rtcp.senderssrc",
 881                                 FT_UINT32,
 882                                 BASE_DEC,
 883                                 NULL,
 884                                 0x0,
 885                                 "", HFILL
 886                         }
 887                 },
 888                 {
 889                         &hf_rtcp_ntp,
 890                         {
 891                                 "NTP timestamp",
 892                                 "rtcp.timestamp.ntp",
 893                                 FT_STRING,
 894                                 BASE_NONE,
 895                                 NULL,
 896                                 0x0,
 897                                 "", HFILL
 898                         }
 899                 },
 900                 {
 901                         &hf_rtcp_rtp_timestamp,
 902                         {
 903                                 "RTP timestamp",
 904                                 "rtcp.timestamp.rtp",
 905                                 FT_UINT32,
 906                                 BASE_DEC,
 907                                 NULL,
 908                                 0x0,
 909                                 "", HFILL
 910                         }
 911                 },
 912                 {
 913                         &hf_rtcp_sender_pkt_cnt,
 914                         {
 915                                 "Sender's packet count",
 916                                 "rtcp.sender.packetcount",
 917                                 FT_UINT32,
 918                                 BASE_DEC,
 919                                 NULL,
 920                                 0x0,
 921                                 "", HFILL
 922                         }
 923                 },
 924                 {
 925                         &hf_rtcp_sender_oct_cnt,
 926                         {
 927                                 "Sender's octet count",
 928                                 "rtcp.sender.octetcount",
 929                                 FT_UINT32,
 930                                 BASE_DEC,
 931                                 NULL,
 932                                 0x0,
 933                                 "", HFILL
 934                         }
 935                 },
 936                 {
 937                         &hf_rtcp_ssrc_source,
 938                         {
 939                                 "Identifier",
 940                                 "rtcp.ssrc.identifier",
 941                                 FT_UINT32,
 942                                 BASE_DEC,
 943                                 NULL,
 944                                 0x0,
 945                                 "", HFILL
 946                         }
 947                 },
 948                 {
 949                         &hf_rtcp_ssrc_fraction,
 950                         {
 951                                 "Fraction lost",
 952                                 "rtcp.ssrc.fraction",
 953                                 FT_UINT8,
 954                                 BASE_DEC,
 955                                 NULL,
 956                                 0x0,
 957                                 "", HFILL
 958                         }
 959                 },
 960                 {
 961                         &hf_rtcp_ssrc_cum_nr,
 962                         {
 963                                 "Cumulative number of packets lost",
 964                                 "rtcp.ssrc.cum_nr",
 965                                 FT_UINT32,
 966                                 BASE_DEC,
 967                                 NULL,
 968                                 0x0,
 969                                 "", HFILL
 970                         }
 971                 },
 972                 {
 973                         &hf_rtcp_ssrc_ext_high_seq,
 974                         {
 975                                 "Extended highest sequence number received",
 976                                 "rtcp.ssrc.ext_high",
 977                                 FT_UINT32,
 978                                 BASE_DEC,
 979                                 NULL,
 980                                 0x0,
 981                                 "", HFILL
 982                         }
 983                 },
 984                 {
 985                         &hf_rtcp_ssrc_high_seq,
 986                         {
 987                                 "Highest sequence number received",
 988                                 "rtcp.ssrc.high_seq",
 989                                 FT_UINT16,
 990                                 BASE_DEC,
 991                                 NULL,
 992                                 0x0,
 993                                 "", HFILL
 994                         }
 995                 },
 996                 {
 997                         &hf_rtcp_ssrc_high_cycles,
 998                         {
 999                                 "Sequence number cycles count",
1000                                 "rtcp.ssrc.high_cycles",
1001                                 FT_UINT16,
1002                                 BASE_DEC,
1003                                 NULL,
1004                                 0x0,
1005                                 "", HFILL
1006                         }
1007                 },
1008                 {
1009                         &hf_rtcp_ssrc_jitter,
1010                         {
1011                                 "Interarrival jitter",
1012                                 "rtcp.ssrc.jitter",
1013                                 FT_UINT32,
1014                                 BASE_DEC,
1015                                 NULL,
1016                                 0x0,
1017                                 "", HFILL
1018                         }
1019                 },
1020                 {
1021                         &hf_rtcp_ssrc_lsr,
1022                         {
1023                                 "Last SR timestamp",
1024                                 "rtcp.ssrc.lsr",
1025                                 FT_UINT32,
1026                                 BASE_DEC,
1027                                 NULL,
1028                                 0x0,
1029                                 "", HFILL
1030                         }
1031                 },
1032                 {
1033                         &hf_rtcp_ssrc_dlsr,
1034                         {
1035                                 "Delay since last SR timestamp",
1036                                 "rtcp.ssrc.dlsr",
1037                                 FT_UINT32,
1038                                 BASE_DEC,
1039                                 NULL,
1040                                 0x0,
1041                                 "", HFILL
1042                         }
1043                 },
1044                 {
1045                         &hf_rtcp_ssrc_csrc,
1046                         {
1047                                 "SSRC / CSRC identifier",
1048                                 "rtcp.sdes.ssrc_csrc",
1049                                 FT_UINT32,
1050                                 BASE_DEC,
1051                                 NULL,
1052                                 0x0,
1053                                 "", HFILL
1054                         }
1055                 },
1056                 {
1057                         &hf_rtcp_ssrc_type,
1058                         {
1059                                 "Type",
1060                                 "rtcp.sdes.type",
1061                                 FT_UINT8,
1062                                 BASE_DEC,
1063                                 VALS( rtcp_sdes_type_vals ),
1064                                 0x0,
1065                                 "", HFILL
1066                         }
1067                 },
1068                 {
1069                         &hf_rtcp_ssrc_length,
1070                         {
1071                                 "Length",
1072                                 "rtcp.sdes.length",
1073                                 FT_UINT32,
1074                                 BASE_DEC,
1075                                 NULL,
1076                                 0x0,
1077                                 "", HFILL
1078                         }
1079                 },
1080                 {
1081                         &hf_rtcp_ssrc_text,
1082                         {
1083                                 "Text",
1084                                 "rtcp.sdes.text",
1085                                 FT_STRING,
1086                                 BASE_NONE,
1087                                 NULL,
1088                                 0x0,
1089                                 "", HFILL
1090                         }
1091                 },
1092                 {
1093                         &hf_rtcp_ssrc_prefix_len,
1094                         {
1095                                 "Prefix length",
1096                                 "rtcp.sdes.prefix.length",
1097                                 FT_UINT8,
1098                                 BASE_DEC,
1099                                 NULL,
1100                                 0x0,
1101                                 "", HFILL
1102                         }
1103                 },
1104                 {
1105                         &hf_rtcp_ssrc_prefix_string,
1106                         {
1107                                 "Prefix string",
1108                                 "rtcp.sdes.prefix.string",
1109                                 FT_STRING,
1110                                 BASE_NONE,
1111                                 NULL,
1112                                 0x0,
1113                                 "", HFILL
1114                         }
1115                 },
1116                 {
1117                         &hf_rtcp_subtype,
1118                         {
1119                                 "Subtype",
1120                                 "rtcp.app.subtype",
1121                                 FT_UINT8,
1122                                 BASE_DEC,
1123                                 NULL,
1124                                 0x0,
1125                                 "", HFILL
1126                         }
1127                 },
1128                 {
1129                         &hf_rtcp_name_ascii,
1130                         {
1131                                 "Name (ASCII)",
1132                                 "rtcp.app.name",
1133                                 FT_STRING,
1134                                 BASE_NONE,
1135                                 NULL,
1136                                 0x0,
1137                                 "", HFILL
1138                         }
1139                 },
1140                 {
1141                         &hf_rtcp_app_data,
1142                         {
1143                                 "Application specific data",
1144                                 "rtcp.app.data",
1145                                 FT_BYTES,
1146                                 BASE_NONE,
1147                                 NULL,
1148                                 0x0,
1149                                 "", HFILL
1150                         }
1151                 },
1152                 {
1153                         &hf_rtcp_fsn,
1154                         {
1155                                 "First sequence number",
1156                                 "rtcp.nack.fsn",
1157                                 FT_UINT16,
1158                                 BASE_DEC,
1159                                 NULL,
1160                                 0x0,
1161                                 "", HFILL
1162                         }
1163                 },
1164                 {
1165                         &hf_rtcp_blp,
1166                         {
1167                                 "Bitmask of following lost packets",
1168                                 "rtcp.nack.blp",
1169                                 FT_UINT16,
1170                                 BASE_DEC,
1171                                 NULL,
1172                                 0x0,
1173                                 "", HFILL
1174                         }
1175                 },
1176                 {
1177                         &hf_rtcp_padding_count,
1178                         {
1179                                 "Padding count",
1180                                 "rtcp.padding.count",
1181                                 FT_UINT8,
1182                                 BASE_DEC,
1183                                 NULL,
1184                                 0x0,
1185                                 "", HFILL
1186                         }
1187                 },
1188                 {
1189                         &hf_rtcp_padding_data,
1190                         {
1191                                 "Padding data",
1192                                 "rtcp.padding.data",
1193                                 FT_BYTES,
1194                                 BASE_NONE,
1195                                 NULL,
1196                                 0x0,
1197                                 "", HFILL
1198                         }
1199                 },
1200 };
1201
1202         static gint *ett[] =
1203         {
1204                 &ett_rtcp,
1205                 &ett_ssrc,
1206                 &ett_ssrc_item,
1207                 &ett_ssrc_ext_high,
1208                 &ett_sdes,
1209                 &ett_sdes_item,
1210         };
1211
1212
1213         proto_rtcp = proto_register_protocol("Real-time Transport Control Protocol",
1214             "RTCP", "rtcp");
1215         proto_register_field_array(proto_rtcp, hf, array_length(hf));
1216         proto_register_subtree_array(ett, array_length(ett));
1217
1218         register_dissector("rtcp", dissect_rtcp, proto_rtcp);
1219
1220 #if 0
1221         register_init_routine( &rtcp_init );
1222 #endif
1223 }
1224
1225 void
1226 proto_reg_handoff_rtcp(void)
1227 {
1228         dissector_handle_t rtcp_handle;
1229
1230         /*
1231          * Register this dissector as one that can be selected by a
1232          * UDP port number.
1233          */
1234         rtcp_handle = find_dissector("rtcp");
1235         dissector_add_handle("udp.port", rtcp_handle);
1236 }