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-rw-r--r--epan/dissectors/packet-urtp.c581
1 files changed, 581 insertions, 0 deletions
diff --git a/epan/dissectors/packet-urtp.c b/epan/dissectors/packet-urtp.c
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index 0000000000..8f8a666b95
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+++ b/epan/dissectors/packet-urtp.c
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+/* packet-rtp.c
+ *
+ * Routines for uRTP dissection
+ * uRTP = micro Real time Transport Protocol
+ *
+ * Copyright 2011, Harald Welte <laforge@gnumonks.org>
+ *
+ * $Id: packet-urtp.c 35883 2011-02-09 02:27:41Z morriss $
+ *
+ * Wireshark - Network traffic analyzer
+ * By Gerald Combs <gerald@wireshark.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.
+ */
+
+#ifdef HAVE_CONFIG_H
+# include "config.h"
+#endif
+
+#include <glib.h>
+#include <epan/packet.h>
+
+#include <stdio.h>
+
+#include "packet-rtp.h"
+#include <epan/rtp_pt.h>
+#include <epan/conversation.h>
+#include <epan/reassemble.h>
+#include <epan/tap.h>
+
+#include <epan/prefs.h>
+#include <epan/emem.h>
+#include <epan/strutil.h>
+
+static dissector_handle_t urtp_handle;
+
+static int urtp_tap = -1;
+
+/* uRTP header fields */
+static int proto_urtp = -1;
+static int hf_urtp_marker = -1;
+static int hf_urtp_payload_type = -1;
+static int hf_urtp_timestamp = -1;
+static int hf_urtp_num_frames = -1;
+static int hf_urtp_ssrc = -1;
+static int hf_urtp_data = -1;
+
+/* uRTP fields defining a sub tree */
+static gint ett_urtp = -1;
+
+/* Forward declaration we need below */
+void proto_reg_handoff_urtp(void);
+
+static dissector_handle_t data_handle;
+static dissector_handle_t amr_handle;
+
+static const value_string urtp_payload_type_vals[] =
+{
+ { 0, NULL },
+};
+
+value_string_ext urtp_payload_type_vals_ext = VALUE_STRING_EXT_INIT(urtp_payload_type_vals);
+
+
+#if 0
+/*
+ * Process the payload of the RTP packet, hand it to the subdissector
+ */
+static void
+process_rtp_payload(tvbuff_t *newtvb, packet_info *pinfo, proto_tree *tree,
+ proto_tree *rtp_tree,
+ unsigned int payload_type)
+{
+ struct _rtp_conversation_info *p_conv_data = NULL;
+ gboolean found_match = FALSE;
+ int payload_len;
+ struct srtp_info *srtp_info;
+ int offset=0;
+
+ payload_len = tvb_length_remaining(newtvb, offset);
+
+ /* first check if this is added as an SRTP stream - if so, don't try to dissector the payload data for now */
+ p_conv_data = p_get_proto_data(pinfo->fd, proto_rtp);
+ if (p_conv_data && p_conv_data->srtp_info) {
+ srtp_info = p_conv_data->srtp_info;
+ payload_len -= srtp_info->mki_len + srtp_info->auth_tag_len;
+#if 0
+#error Currently the srtp_info structure contains no cypher data, see packet-sdp.c adding dummy_srtp_info structure
+ if (p_conv_data->srtp_info->encryption_algorithm==SRTP_ENC_ALG_NULL) {
+ if (rtp_tree)
+ proto_tree_add_text(rtp_tree, newtvb, offset, payload_len, "SRTP Payload with NULL encryption");
+ }
+ else
+#endif
+ {
+ if (rtp_tree)
+ proto_tree_add_item(rtp_tree, hf_srtp_encrypted_payload, newtvb, offset, payload_len, FALSE);
+ found_match = TRUE; /* use this flag to prevent dissection below */
+ }
+ offset += payload_len;
+
+ if (srtp_info->mki_len) {
+ proto_tree_add_item(rtp_tree, hf_srtp_mki, newtvb, offset, srtp_info->mki_len, FALSE);
+ offset += srtp_info->mki_len;
+ }
+
+ if (srtp_info->auth_tag_len) {
+ proto_tree_add_item(rtp_tree, hf_srtp_auth_tag, newtvb, offset, srtp_info->auth_tag_len, FALSE);
+ offset += srtp_info->auth_tag_len;
+ }
+ }
+
+ /* if the payload type is dynamic, we check if the conv is set and we look for the pt definition */
+ else if ( (payload_type >= PT_UNDF_96 && payload_type <= PT_UNDF_127) ) {
+ if (p_conv_data && p_conv_data->rtp_dyn_payload) {
+ gchar *payload_type_str = NULL;
+ encoding_name_and_rate_t *encoding_name_and_rate_pt = NULL;
+ encoding_name_and_rate_pt = g_hash_table_lookup(p_conv_data->rtp_dyn_payload, &payload_type);
+ if (encoding_name_and_rate_pt) {
+ payload_type_str = encoding_name_and_rate_pt->encoding_name;
+ }
+ if (payload_type_str){
+ found_match = dissector_try_string(rtp_dyn_pt_dissector_table,
+ payload_type_str, newtvb, pinfo, tree);
+ /* If payload type string set from conversation and
+ * no matching dissector found it's probably because no subdissector
+ * exists. Don't call the dissectors based on payload number
+ * as that'd probably be the wrong dissector in this case.
+ * Just add it as data.
+ */
+ if(found_match==FALSE)
+ proto_tree_add_item( rtp_tree, hf_rtp_data, newtvb, 0, -1, FALSE );
+ return;
+ }
+
+ }
+ }
+
+ /* if we don't found, it is static OR could be set static from the preferences */
+ if (!found_match && !dissector_try_uint(rtp_pt_dissector_table, payload_type, newtvb, pinfo, tree))
+ proto_tree_add_item( rtp_tree, hf_rtp_data, newtvb, 0, -1, FALSE );
+
+}
+
+/* Rtp payload reassembly
+ *
+ * This handles the reassembly of PDUs for higher-level protocols.
+ *
+ * We're a bit limited on how we can cope with out-of-order packets, because
+ * we don't have any idea of where the datagram boundaries are. So if we see
+ * packets A, C, B (all of which comprise a single datagram), we cannot know
+ * that C should be added to the same datagram as A, until we come to B (which
+ * may or may not actually be present...).
+ *
+ * What we end up doing in this case is passing A+B to the subdissector as one
+ * datagram, and make out that a new one starts on C.
+ */
+static 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 data_reported_len,
+ unsigned int payload_type )
+{
+ tvbuff_t *newtvb;
+ struct _rtp_conversation_info *p_conv_data= NULL;
+ gboolean must_desegment = FALSE;
+ rtp_private_conv_info *finfo = NULL;
+ rtp_multisegment_pdu *msp = NULL;
+ guint32 seqno;
+
+ /* Retrieve RTPs idea of a converation */
+ p_conv_data = p_get_proto_data(pinfo->fd, proto_rtp);
+
+ if(p_conv_data != NULL)
+ finfo = p_conv_data->rtp_conv_info;
+
+ if(finfo == NULL || !desegment_rtp) {
+ /* Hand the whole lot off to the subdissector */
+ newtvb=tvb_new_subset(tvb,offset,data_len,data_reported_len);
+ process_rtp_payload(newtvb, pinfo, tree, rtp_tree, payload_type);
+ return;
+ }
+
+ seqno = p_conv_data->extended_seqno;
+
+ pinfo->can_desegment = 2;
+ pinfo->desegment_offset = 0;
+ pinfo->desegment_len = 0;
+
+#ifdef DEBUG_FRAGMENTS
+ g_debug("%d: RTP Part of convo %d(%p); seqno %d",
+ pinfo->fd->num,
+ p_conv_data->frame_number, p_conv_data,
+ seqno
+ );
+#endif
+
+ /* look for a pdu which we might be extending */
+ msp = (rtp_multisegment_pdu *)se_tree_lookup32_le(finfo->multisegment_pdus,seqno-1);
+
+ if(msp && msp->startseq < seqno && msp->endseq >= seqno) {
+ guint32 fid = msp->startseq;
+ fragment_data *fd_head;
+
+#ifdef DEBUG_FRAGMENTS
+ g_debug("\tContinues fragment %d", fid);
+#endif
+
+ /* we always assume the datagram is complete; if this is the
+ * first pass, that's our best guess, and if it's not, what we
+ * say gets ignored anyway.
+ */
+ fd_head = fragment_add_seq(tvb, offset, pinfo, fid, fragment_table,
+ seqno-msp->startseq, data_len, FALSE);
+
+ newtvb = process_reassembled_data(tvb,offset, pinfo, "Reassembled RTP", fd_head,
+ &rtp_fragment_items, NULL, tree);
+
+#ifdef DEBUG_FRAGMENTS
+ g_debug("\tFragment Coalesced; fd_head=%p, newtvb=%p (len %d)",fd_head, newtvb,
+ newtvb?tvb_reported_length(newtvb):0);
+#endif
+
+ if(newtvb != NULL) {
+ /* Hand off to the subdissector */
+ process_rtp_payload(newtvb, pinfo, tree, rtp_tree, payload_type);
+
+ /*
+ * Check to see if there were any complete fragments within the chunk
+ */
+ if( pinfo->desegment_len && pinfo->desegment_offset == 0 )
+ {
+#ifdef DEBUG_FRAGMENTS
+ g_debug("\tNo complete pdus in payload" );
+#endif
+ /* Mark the fragments and not complete yet */
+ fragment_set_partial_reassembly(pinfo, fid, fragment_table);
+
+ /* we must need another segment */
+ msp->endseq = MIN(msp->endseq,seqno) + 1;
+ }
+ else
+ {
+ /*
+ * Data was dissected so add the protocol tree to the display
+ */
+ proto_item *rtp_tree_item, *frag_tree_item;
+ /* this nargery is to insert the fragment tree into the main tree
+ * between the RTP protocol entry and the subdissector entry */
+ show_fragment_tree(fd_head, &rtp_fragment_items, tree, pinfo, newtvb, &frag_tree_item);
+ rtp_tree_item = proto_item_get_parent( proto_tree_get_parent( rtp_tree ));
+ if( frag_tree_item && rtp_tree_item )
+ proto_tree_move_item( tree, rtp_tree_item, frag_tree_item );
+
+
+ if(pinfo->desegment_len)
+ {
+ /* the higher-level dissector has asked for some more data - ie,
+ the end of this segment does not coincide with the end of a
+ higher-level PDU. */
+ must_desegment = TRUE;
+ }
+ }
+
+ }
+
+ }
+ else
+ {
+ /*
+ * The segment is not the continuation of a fragmented segment
+ * so process it as normal
+ */
+#ifdef DEBUG_FRAGMENTS
+ g_debug("\tRTP non-fragment payload");
+#endif
+ newtvb = tvb_new_subset( tvb, offset, data_len, data_reported_len );
+
+ /* Hand off to the subdissector */
+ process_rtp_payload(newtvb, pinfo, tree, rtp_tree, payload_type);
+
+ if(pinfo->desegment_len) {
+ /* the higher-level dissector has asked for some more data - ie,
+ the end of this segment does not coincide with the end of a
+ higher-level PDU. */
+ must_desegment = TRUE;
+ }
+ }
+
+ /*
+ * There were bytes left over that the higher protocol couldn't dissect so save them
+ */
+ if(must_desegment)
+ {
+ guint32 deseg_offset = pinfo->desegment_offset;
+ guint32 frag_len = tvb_reported_length_remaining(newtvb, deseg_offset);
+ fragment_data *fd_head = NULL;
+
+#ifdef DEBUG_FRAGMENTS
+ g_debug("\tRTP Must Desegment: tvb_len=%d ds_len=%d %d frag_len=%d ds_off=%d",
+ tvb_reported_length(newtvb),
+ pinfo->desegment_len,
+ pinfo->fd->flags.visited,
+ frag_len,
+ deseg_offset);
+#endif
+ /* allocate a new msp for this pdu */
+ msp = se_alloc(sizeof(rtp_multisegment_pdu));
+ msp->startseq = seqno;
+ msp->endseq = seqno+1;
+ se_tree_insert32(finfo->multisegment_pdus,seqno,msp);
+
+ /*
+ * Add the fragment to the fragment table
+ */
+ fd_head = fragment_add_seq(newtvb,deseg_offset, pinfo, seqno, fragment_table, 0, frag_len,
+ TRUE );
+
+ if(fd_head != NULL)
+ {
+ if( fd_head->reassembled_in != 0 && !(fd_head->flags & FD_PARTIAL_REASSEMBLY) )
+ {
+ proto_item *rtp_tree_item;
+ rtp_tree_item = proto_tree_add_uint( tree, hf_rtp_reassembled_in,
+ newtvb, deseg_offset, tvb_reported_length_remaining(newtvb,deseg_offset),
+ fd_head->reassembled_in);
+ PROTO_ITEM_SET_GENERATED(rtp_tree_item);
+#ifdef DEBUG_FRAGMENTS
+ g_debug("\tReassembled in %d", fd_head->reassembled_in);
+#endif
+ }
+ else
+ {
+#ifdef DEBUG_FRAGMENTS
+ g_debug("\tUnfinished fragment");
+#endif
+ /* this fragment is never reassembled */
+ proto_tree_add_text( tree, tvb, deseg_offset, -1,"RTP fragment, unfinished");
+ }
+ }
+ else
+ {
+ /*
+ * This fragment was the first fragment in a new entry in the
+ * frag_table; we don't yet know where it is reassembled
+ */
+#ifdef DEBUG_FRAGMENTS
+ g_debug("\tnew pdu");
+#endif
+ }
+
+ if( pinfo->desegment_offset == 0 )
+ {
+ col_set_str(pinfo->cinfo, COL_PROTOCOL, "RTP");
+ col_set_str(pinfo->cinfo, COL_INFO, "[RTP segment of a reassembled PDU]");
+ }
+ }
+
+
+
+ pinfo->can_desegment = 0;
+ pinfo->desegment_offset = 0;
+ pinfo->desegment_len = 0;
+}
+#endif
+
+static const unsigned int amr_ft_len_bits[] = {
+ [0] = 95,
+ [1] = 103,
+ [2] = 118,
+ [3] = 134,
+ [4] = 148,
+ [5] = 159,
+ [6] = 204,
+ [7] = 244,
+ [8] = 39,
+};
+
+static int amr_bytelen_padded(guint8 ft)
+{
+ unsigned int bits;
+ int bytes;
+
+ if (ft > 8)
+ return -1;
+
+ bits = amr_ft_len_bits[ft];
+ bytes = bits / 8;
+ if (bits % 8)
+ bytes++;
+
+ return bytes;
+}
+
+static void
+dissect_urtp( tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree )
+{
+ proto_item *ti = NULL;
+ proto_tree *urtp_tree = NULL;
+ gboolean marker_set = 0;
+ unsigned int payload_type;
+ gchar *payload_type_str = NULL;
+ unsigned int offset = 0;
+ guint8 timestamp, sync_src, num_frames;
+
+ col_set_str(pinfo->cinfo, COL_PROTOCOL, "uRTP");
+
+ timestamp = tvb_get_guint8(tvb, offset);
+ sync_src = tvb_get_guint8(tvb, offset+1);
+ payload_type = tvb_get_guint8(tvb, offset+2) & 0xF;
+ num_frames = tvb_get_guint8(tvb, offset+2) >> 4;
+
+ col_add_fstr( pinfo->cinfo, COL_INFO,
+ "PT=%s, SSRC=0x%X, Time=%u%s",
+ payload_type_str ? payload_type_str : val_to_str_ext( payload_type, &urtp_payload_type_vals_ext,"Unknown (%u)" ),
+ sync_src,
+ timestamp,
+ marker_set ? ", Mark " : " ");
+
+
+ if ( tree ) {
+ unsigned int i;
+ /* Create RTP protocol tree */
+ ti = proto_tree_add_item(tree, proto_urtp, tvb, offset, -1, FALSE );
+ urtp_tree = proto_item_add_subtree(ti, ett_urtp );
+
+ proto_tree_add_item( urtp_tree, hf_urtp_timestamp, tvb,
+ offset, 1, FALSE );
+ proto_tree_add_item( urtp_tree, hf_urtp_ssrc, tvb,
+ offset+1, 1, FALSE );
+ proto_tree_add_item( urtp_tree, hf_urtp_payload_type, tvb,
+ offset+2, 1, FALSE );
+ proto_tree_add_item( urtp_tree, hf_urtp_num_frames, tvb,
+ offset+2, 1, FALSE );
+
+ offset += 3;
+
+ for (i = 0; i < num_frames; i++) {
+ guint8 oct1, ft;
+ tvbuff_t *subtvb;
+ int frame_len;
+
+ oct1 = tvb_get_guint8(tvb, offset+1);
+ ft = (oct1 >> 3) & 0xF;
+ frame_len = amr_bytelen_padded(ft);
+ if (frame_len < 0)
+ return;
+
+ subtvb = tvb_new_subset(tvb, offset, frame_len+2, frame_len+2);
+ call_dissector(amr_handle, subtvb, pinfo, urtp_tree);
+
+ offset += frame_len+2;
+ }
+ }
+
+ if (!pinfo->flags.in_error_pkt)
+ tap_queue_packet(urtp_tap, pinfo, NULL);
+}
+
+/* Register uRTP */
+
+void
+proto_register_urtp(void)
+{
+ static hf_register_info hf[] =
+ {
+ {
+ &hf_urtp_timestamp,
+ {
+ "Timestamp",
+ "urtp.timestamp",
+ FT_UINT8,
+ BASE_DEC,
+ NULL,
+ 0xFF,
+ NULL, HFILL
+ }
+ },
+ {
+ &hf_urtp_ssrc,
+ {
+ "SSRC",
+ "urtp.ssrc",
+ FT_UINT8,
+ BASE_HEX,
+ NULL,
+ 0xFF,
+ NULL, HFILL
+ }
+ },
+ {
+ &hf_urtp_payload_type,
+ {
+ "Payload Type",
+ "urtp.payload_type",
+ FT_UINT8,
+ BASE_DEC,
+ NULL,
+ 0x0F,
+ NULL, HFILL
+ }
+ },
+ {
+ &hf_urtp_num_frames,
+ {
+ "Number of frames to follow",
+ "urtp.number_samples",
+ FT_UINT8,
+ BASE_DEC,
+ NULL,
+ 0xF0,
+ NULL, HFILL
+ }
+ },
+ {
+ &hf_urtp_data,
+ {
+ "Payload",
+ "urtp.payload",
+ FT_BYTES,
+ BASE_NONE,
+ NULL,
+ 0x0,
+ NULL, HFILL
+ }
+ },
+ };
+
+ static gint *ett[] =
+ {
+ &ett_urtp,
+ };
+
+ proto_urtp = proto_register_protocol("Micro Real-Time Transport Protocol",
+ "uRTP", "urtp");
+ proto_register_field_array(proto_urtp, hf, array_length(hf));
+ proto_register_subtree_array(ett, array_length(ett));
+
+ register_dissector("urtp", dissect_urtp, proto_urtp);
+
+ urtp_tap = register_tap("urtp");
+}
+
+void
+proto_reg_handoff_urtp(void)
+{
+ static gboolean urtp_prefs_initialized = FALSE;
+
+ if (!urtp_prefs_initialized) {
+ urtp_handle = find_dissector("urtp");
+
+ dissector_add_handle("udp.port", urtp_handle); /* for 'decode-as' */
+ //heur_dissector_add( "udp", dissect_urtp_heur, proto_urtp);
+
+ data_handle = find_dissector("data");
+ amr_handle = find_dissector("amr");
+
+ urtp_prefs_initialized = TRUE;
+ }
+}
+
+/*
+ * Local Variables:
+ * c-basic-offset: 8
+ * indent-tabs-mode: t
+ * tab-width: 8
+ * End:
+ */
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