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wireshark/packet-rtp.c

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/* packet-rtp.c
*
* Routines for RTP dissection
* RTP = Real time Transport Protocol
*
* Copyright 2000, Philips Electronics N.V.
* Written by Andreas Sikkema <andreas.sikkema@philips.com>
*
* Ethereal - Network traffic analyzer
* By Gerald Combs <gerald@zing.org>
* Copyright 1998 Gerald Combs
*
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
/*
* This dissector tries to dissect the RTP protocol according to Annex A
* of ITU-T Recommendation H.225.0 (02/98) or RFC 1889
*
* RTP traffic is handled by an even UDP portnumber. This can be any
* port number, but there is a registered port available, port 5004
* See Annex B of ITU-T Recommendation H.225.0, section B.7
*/
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif
#include <glib.h>
#include "packet.h"
#ifdef HAVE_SYS_TYPES_H
# include <sys/types.h>
#endif
#ifdef HAVE_NETINET_IN_H
# include <netinet/in.h>
#endif
#include <stdio.h>
#include <string.h>
#include "packet-rtp.h"
#include "packet-h261.h"
#include "conversation.h"
/* RTP header fields */
static int proto_rtp = -1;
static int hf_rtp_version = -1;
static int hf_rtp_padding = -1;
static int hf_rtp_extension = -1;
static int hf_rtp_csrc_count = -1;
static int hf_rtp_marker = -1;
static int hf_rtp_payload_type = -1;
static int hf_rtp_seq_nr = -1;
static int hf_rtp_timestamp = -1;
static int hf_rtp_ssrc = -1;
static int hf_rtp_csrc_item = -1;
static int hf_rtp_data = -1;
static int hf_rtp_padding_data = -1;
static int hf_rtp_padding_count= -1;
/* RTP header extension fields */
static int hf_rtp_prof_define = -1;
static int hf_rtp_length = -1;
static int hf_rtp_hdr_ext = -1;
/* RTP fields defining a sub tree */
static gint ett_rtp = -1;
static gint ett_csrc_list = -1;
static gint ett_hdr_ext = -1;
/*
* Fields in the first octet of the RTP header.
*/
/* Version is the first 2 bits of the first octet*/
#define RTP_VERSION(octet) ((octet) >> 6)
/* Padding is the third bit; No need to shift, because true is any value
other than 0! */
#define RTP_PADDING(octet) ((octet) & 0x20)
/* Extension bit is the fourth bit */
#define RTP_EXTENSION(octet) ((octet) & 0x10)
/* CSRC count is the last four bits */
#define RTP_CSRC_COUNT(octet) ((octet) & 0xF)
static const value_string rtp_version_vals[] =
{
{ 0, "Old VAT Version" },
{ 1, "First Draft Version" },
{ 2, "RFC 1889 Version" },
{ 0, NULL },
};
/*
* Fields in the second octet of the RTP header.
*/
/* Marker is the first bit of the second octet */
#define RTP_MARKER(octet) ((octet) & 0x80)
/* Payload type is the last 7 bits */
#define RTP_PAYLOAD_TYPE(octet) ((octet) & 0x7F)
/*
* RTP Payload types
* Table B.2 / H.225.0
*/
#define PT_PCMU 0
#define PT_PCMA 8
#define PT_G722 9
#define PT_G723 4
#define PT_G728 15
#define PT_G729 18
#define PT_H261 31
#define PT_H263 34
static const value_string rtp_payload_type_vals[] =
{
{ PT_PCMU, "ITU-T G.711 PCMU" },
{ PT_PCMA, "ITU-T G.711 PCMA" },
{ PT_G722, "ITU-T G.722" },
{ PT_G723, "ITU-T G.723" },
{ PT_G728, "ITU-T G.728" },
{ PT_G729, "ITU-T G.729" },
{ PT_H261, "ITU-T H.261" },
{ PT_H263, "ITU-T H.263" },
{ 0, NULL },
};
static address fake_addr;
static int heur_init = FALSE;
static const char rtp_proto[] = "RTP";
void rtp_add_address( const unsigned char* ip_addr, int prt )
{
address src_addr;
conversation_t* pconv = ( conversation_t* ) NULL;
src_addr.type = AT_IPv4;
src_addr.len = 4;
src_addr.data = ip_addr;
/*
* The first time the function is called let the tcp dissector
* know that we're interested in traffic
*/
if ( ! heur_init ) {
heur_dissector_add( "udp", dissect_rtp_heur );
heur_init = TRUE;
}
/*
* Check if the ip address an dport combination is not
* already registered
*/
pconv = find_conversation( &src_addr, &fake_addr, PT_UDP, prt, 0, 0 );
/*
* If not, add
*/
if ( ! pconv ) {
conversation_new( &src_addr, &fake_addr, PT_UDP, (guint32) prt,
(guint32) 0, ( void * ) rtp_proto, 0 );
}
}
#if 0
static void rtp_init( void )
{
unsigned char* tmp_data;
int i;
/* Create a fake adddress... */
fake_addr.type = AT_IPv4;
fake_addr.len = 4;
tmp_data = malloc( fake_addr.len );
for ( i = 0; i < fake_addr.len; i++) {
tmp_data[i] = 0;
}
fake_addr.data = tmp_data;
}
#endif
gboolean
dissect_rtp_heur( tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree )
{
conversation_t* pconv;
if (!proto_is_protocol_enabled(proto_rtp))
return FALSE; /* RTP has been disabled */
/* This is a heuristic dissector, which means we get all the TCP
* traffic not sent to a known dissector and not claimed by
* a heuristic dissector called before us!
* So we first check if the frame is really meant for us.
*/
if ( ( pconv = find_conversation( &pi.src, &fake_addr, pi.ptype,
pi.srcport, 0, 0 ) ) == NULL ) {
/*
* The source ip:port combination was not what we were
* looking for, check the destination
*/
if ( ( pconv = find_conversation( &pi.dst, &fake_addr,
pi.ptype, pi.destport, 0, 0 ) ) == NULL ) {
return FALSE;
}
}
/*
* An RTP conversation always contains data
*/
if ( pconv->data == NULL )
return FALSE;
/*
* An RTP conversation data always contains "RTP"
*/
if ( strcmp( pconv->data, rtp_proto ) != 0 )
return FALSE;
dissect_rtp( tvb, pinfo, tree );
return TRUE;
}
void
dissect_rtp_data( tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, proto_tree *rtp_tree, int offset, unsigned int data_len, unsigned int payload_type )
{
tvbuff_t *newtvb;
switch( payload_type ) {
case PT_H261:
/*
* What does reported length DO?
*/
newtvb = tvb_new_subset( tvb, offset, data_len, -1 );
dissect_h261(newtvb, pinfo, tree);
break;
default:
proto_tree_add_bytes( rtp_tree, hf_rtp_data, tvb, offset, data_len, tvb_get_ptr( tvb, offset, data_len ) );
break;
}
}
void
dissect_rtp( tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree )
{
proto_item *ti = NULL;
proto_tree *rtp_tree = NULL;
proto_tree *rtp_csrc_tree = NULL;
guint8 octet;
unsigned int version;
gboolean padding_set;
gboolean extension_set;
unsigned int csrc_count;
gboolean marker_set;
unsigned int payload_type;
unsigned int i = 0;
unsigned int hdr_extension= 0;
unsigned int padding_count= 0;
unsigned int offset = 0;
guint16 seq_num;
guint32 timestamp;
guint32 sync_src;
guint32 csrc_item;
CHECK_DISPLAY_AS_DATA(proto_rtp, tvb, pinfo, tree);
pinfo->current_proto = "RTP";
/* Get the fields in the first octet */
octet = tvb_get_guint8( tvb, offset );
version = RTP_VERSION( octet );
padding_set = RTP_PADDING( octet );
extension_set = RTP_EXTENSION( octet );
csrc_count = RTP_CSRC_COUNT( octet );
/* Get the fields in the second octet */
octet = tvb_get_guint8( tvb, offset + 1 );
marker_set = RTP_MARKER( octet );
payload_type = RTP_PAYLOAD_TYPE( octet );
/* Get the subsequent fields */
seq_num = tvb_get_ntohs( tvb, offset + 2 );
timestamp = tvb_get_ntohl( tvb, offset + 4 );
sync_src = tvb_get_ntohl( tvb, offset + 8 );
if ( check_col( pinfo->fd, COL_PROTOCOL ) ) {
col_set_str( pinfo->fd, COL_PROTOCOL, "RTP" );
}
if ( check_col( pinfo->fd, COL_INFO) ) {
col_add_fstr( pinfo->fd, COL_INFO,
"Payload type=%s, SSRC=%u, Seq=%u, Time=%u%s",
val_to_str( payload_type, rtp_payload_type_vals,
"Unknown (%u)" ),
sync_src,
seq_num,
timestamp,
marker_set ? ", Mark" : "");
}
if ( tree ) {
ti = proto_tree_add_item( tree, proto_rtp, tvb, offset, tvb_length_remaining( tvb, offset ), FALSE );
rtp_tree = proto_item_add_subtree( ti, ett_rtp );
proto_tree_add_uint( rtp_tree, hf_rtp_version, tvb,
offset, 1, version );
proto_tree_add_boolean( rtp_tree, hf_rtp_padding, tvb,
offset, 1, padding_set );
proto_tree_add_boolean( rtp_tree, hf_rtp_extension, tvb,
offset, 1, extension_set );
proto_tree_add_uint( rtp_tree, hf_rtp_csrc_count, tvb,
offset, 1, csrc_count );
offset++;
proto_tree_add_boolean( rtp_tree, hf_rtp_marker, tvb, offset,
1, marker_set );
proto_tree_add_uint( rtp_tree, hf_rtp_payload_type, tvb,
offset, 1, payload_type );
offset++;
/* Sequence number 16 bits (2 octets) */
proto_tree_add_uint( rtp_tree, hf_rtp_seq_nr, tvb, offset, 2, seq_num );
offset += 2;
/* Timestamp 32 bits (4 octets) */
proto_tree_add_uint( rtp_tree, hf_rtp_timestamp, tvb, offset, 4, timestamp );
offset += 4;
/* Synchronization source identifier 32 bits (4 octets) */
proto_tree_add_uint( rtp_tree, hf_rtp_ssrc, tvb, offset, 4, sync_src );
offset += 4;
/* CSRC list*/
if ( csrc_count > 0 ) {
ti = proto_tree_add_text(rtp_tree, tvb, offset, csrc_count * 4, "Contributing Source identifiers");
rtp_csrc_tree = proto_item_add_subtree( ti, ett_csrc_list );
for (i = 0; i < csrc_count; i++ ) {
csrc_item = tvb_get_ntohl( tvb, offset );
proto_tree_add_uint_format( rtp_csrc_tree,
hf_rtp_csrc_item, tvb, offset, 4,
csrc_item,
"CSRC item %d: %u",
i, csrc_item );
offset += 4;
}
}
/* Optional RTP header extension */
if ( extension_set ) {
/* Defined by profile field is 16 bits (2 octets) */
proto_tree_add_uint( rtp_tree, hf_rtp_prof_define, tvb, offset, 2, tvb_get_ntohs( tvb, offset ) );
offset += 2;
hdr_extension = tvb_get_ntohs( tvb, offset );
proto_tree_add_uint( rtp_tree, hf_rtp_length, tvb,
offset, 2, hdr_extension);
if ( hdr_extension > 0 ) {
ti = proto_tree_add_text(rtp_tree, tvb, offset, csrc_count * 4, "Header extensions");
/* I'm re-using the old tree variable here
from the CSRC list!*/
rtp_csrc_tree = proto_item_add_subtree( ti,
ett_hdr_ext );
for (i = 0; i < hdr_extension; i++ ) {
proto_tree_add_uint( rtp_csrc_tree, hf_rtp_hdr_ext, tvb, offset, 4, tvb_get_ntohl( tvb, offset ) );
offset += 4;
}
}
}
/* Find the padding
* The padding count is found in the LAST octet of the packet
* This contains the number of octets that can be ignored at
* the end of the packet
*/
if ( padding_set ) {
padding_count = tvb_get_guint8( tvb, tvb_length( tvb ) - 1 );
if ( padding_count > 0 ) {
dissect_rtp_data( tvb, pinfo, tree, rtp_tree, offset, tvb_length( tvb ) - padding_count, payload_type );
offset = tvb_length( tvb ) - padding_count;
proto_tree_add_item( rtp_tree, hf_rtp_padding_data, tvb, offset, padding_count - 1, FALSE );
offset += padding_count - 1;
proto_tree_add_item( rtp_tree, hf_rtp_padding_count, tvb, offset, 1, FALSE );
}
else {
proto_tree_add_item( rtp_tree, hf_rtp_padding_count, tvb, tvb_length( tvb ) - 1, 1, FALSE );
}
}
else {
dissect_rtp_data( tvb, pinfo, tree, rtp_tree, offset, tvb_length_remaining( tvb, offset ) - padding_count, payload_type );
}
}
}
void
proto_register_rtp(void)
{
static hf_register_info hf[] =
{
{
&hf_rtp_version,
{
"Version",
"rtp.version",
FT_UINT8,
BASE_DEC,
VALS(rtp_version_vals),
0x0,
""
}
},
{
&hf_rtp_padding,
{
"Padding",
"rtp.padding",
FT_BOOLEAN,
BASE_NONE,
NULL,
0x0,
""
}
},
{
&hf_rtp_extension,
{
"Extension",
"rtp.ext",
FT_BOOLEAN,
BASE_NONE,
NULL,
0x0,
""
}
},
{
&hf_rtp_csrc_count,
{
"Contributing source identifiers count",
"rtp.cc",
FT_UINT8,
BASE_DEC,
NULL,
0x0,
""
}
},
{
&hf_rtp_marker,
{
"Marker",
"rtp.marker",
FT_BOOLEAN,
BASE_NONE,
NULL,
0x0,
""
}
},
{
&hf_rtp_payload_type,
{
"Payload type",
"rtp.p_type",
FT_UINT8,
BASE_DEC,
VALS(rtp_payload_type_vals),
0x0,
""
}
},
{
&hf_rtp_seq_nr,
{
"Sequence number",
"rtp.seq",
FT_UINT16,
BASE_DEC,
NULL,
0x0,
""
}
},
{
&hf_rtp_timestamp,
{
"Timestamp",
"rtp.timestamp",
FT_UINT32,
BASE_DEC,
NULL,
0x0,
""
}
},
{
&hf_rtp_ssrc,
{
"Synchronization Source identifier",
"rtp.ssrc",
FT_UINT32,
BASE_DEC,
NULL,
0x0,
""
}
},
{
&hf_rtp_prof_define,
{
"Defined by profile",
"rtp.ext.profile",
FT_UINT16,
BASE_DEC,
NULL,
0x0,
""
}
},
{
&hf_rtp_length,
{
"Extension length",
"rtp.ext.len",
FT_UINT16,
BASE_DEC,
NULL,
0x0,
""
}
},
{
&hf_rtp_csrc_item,
{
"CSRC item",
"rtp.csrc.item",
FT_UINT32,
BASE_DEC,
NULL,
0x0,
""
}
},
{
&hf_rtp_hdr_ext,
{
"Header extension",
"rtp.hdr_ext",
FT_UINT32,
BASE_DEC,
NULL,
0x0,
""
}
},
{
&hf_rtp_data,
{
"Payload",
"rtp.payload",
FT_BYTES,
BASE_HEX,
NULL,
0x0,
""
}
},
{
&hf_rtp_padding_data,
{
"Padding data",
"rtp.padding.data",
FT_BYTES,
BASE_HEX,
NULL,
0x0,
""
}
},
{
&hf_rtp_padding_count,
{
"Padding count",
"rtp.padding.count",
FT_UINT8,
BASE_DEC,
NULL,
0x0,
""
}
},
};
static gint *ett[] =
{
&ett_rtp,
&ett_csrc_list,
&ett_hdr_ext,
};
proto_rtp = proto_register_protocol("Real-Time Transport Protocol", "rtp");
proto_register_field_array(proto_rtp, hf, array_length(hf));
proto_register_subtree_array(ett, array_length(ett));
#if 0
register_init_routine( &rtp_init );
#endif
}
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