forked from osmocom/wireshark
7172127412
svn path=/trunk/; revision=27911
233 lines
6.6 KiB
C
233 lines
6.6 KiB
C
/* packet-srp.c
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* Routines for H.324/SRP dissection
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* 2004 Richard van der Hoff <richardv@mxtelecom.com>
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*
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* $Id$
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*
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* Wireshark - Network traffic analyzer
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* By Gerald Combs <gerald@wireshark.org>
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* Copyright 1998 Gerald Combs
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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*/
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#ifdef HAVE_CONFIG_H
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# include "config.h"
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#endif
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#include <gmodule.h>
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#include <glib.h>
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#include <epan/bitswap.h>
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#include <epan/circuit.h>
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#include <epan/packet.h>
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#include <epan/stream.h>
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/* #include <epan/reassemble.h> */
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#include <epan/crc16.h>
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/* Wireshark ID of the protocols */
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static int proto_srp = -1;
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static int proto_ccsrl = -1;
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/* The following hf_* variables are used to hold the Wireshark IDs of
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* our header fields; they are filled out when we call
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* proto_register_field_array() in proto_register_srp()
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*/
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static int hf_srp_header = -1;
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static int hf_srp_seqno = -1;
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static int hf_srp_crc = -1;
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static int hf_srp_crc_bad = -1;
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static int hf_ccsrl_ls = -1;
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/* These are the ids of the subtrees that we may be creating */
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static gint ett_srp = -1;
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static gint ett_ccsrl = -1;
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static dissector_handle_t ccsrl_handle;
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static dissector_handle_t h245dg_handle;
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/*****************************************************************************/
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#define SRP_SRP_COMMAND 249
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#define SRP_SRP_RESPONSE 251
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#define SRP_NSRP_RESPONSE 247
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static const value_string srp_frame_types[] = {
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{SRP_SRP_COMMAND, "SRP command"},
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{SRP_SRP_RESPONSE, "SRP response"},
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{SRP_NSRP_RESPONSE, "NSRP response"},
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{0,NULL}
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};
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static const value_string ccsrl_ls_vals[] = {
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{0xFF, "Yes"},
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{0x00, "No"},
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{0,NULL}
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};
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/*****************************************************************************/
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static void dissect_ccsrl(tvbuff_t * tvb, packet_info * pinfo, proto_tree * tree)
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{
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proto_item *ccsrl_item;
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proto_tree *ccsrl_tree=NULL;
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guint8 lastseg = tvb_get_guint8(tvb,0);
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tvbuff_t *next_tvb;
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/* add the 'ccsrl' tree to the main tree */
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if (tree) {
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ccsrl_item = proto_tree_add_item (tree, proto_ccsrl, tvb, 0, -1, FALSE);
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ccsrl_tree = proto_item_add_subtree (ccsrl_item, ett_ccsrl);
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proto_tree_add_uint(ccsrl_tree,hf_ccsrl_ls,tvb,0,1,lastseg);
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}
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/* XXX add support for reassembly of fragments */
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/* XXX currently, we always dissect as H245. It's not necessarily
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that though.
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*/
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next_tvb = tvb_new_subset(tvb, 1, -1, -1 );
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call_dissector( h245dg_handle, next_tvb, pinfo, ccsrl_tree );
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}
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static void dissect_srp_command(tvbuff_t * tvb, packet_info * pinfo, proto_tree * srp_tree)
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{
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tvbuff_t *next_tvb;
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guint payload_len;
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if( srp_tree )
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proto_tree_add_item(srp_tree,hf_srp_seqno,tvb,1,1,FALSE);
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payload_len = tvb_reported_length_remaining(tvb,4);
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next_tvb = tvb_new_subset(tvb, 2, payload_len, payload_len );
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/* XXX currently, we always dissect as CCSRL. It's only that in
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* H324/Annex C though.
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*/
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call_dissector(ccsrl_handle, next_tvb, pinfo, srp_tree );
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}
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static void dissect_srp (tvbuff_t * tvb, packet_info * pinfo, proto_tree * tree)
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{
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proto_item *srp_item = NULL;
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proto_tree *srp_tree = NULL;
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proto_item *hidden_item;
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guint8 header = tvb_get_guint8(tvb,0);
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/* add the 'srp' tree to the main tree */
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if (tree) {
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srp_item = proto_tree_add_item (tree, proto_srp, tvb, 0, -1, FALSE);
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srp_tree = proto_item_add_subtree (srp_item, ett_srp);
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proto_tree_add_uint(srp_tree,hf_srp_header,tvb,0,1,header);
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}
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switch( header ) {
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case SRP_SRP_COMMAND:
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dissect_srp_command(tvb,pinfo,srp_tree);
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break;
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case SRP_SRP_RESPONSE:
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break;
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case SRP_NSRP_RESPONSE:
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if( srp_tree )
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proto_tree_add_item(srp_tree,hf_srp_seqno,tvb,1,1,FALSE);
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break;
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default:
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break;
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}
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if( srp_tree ) {
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guint16 crc, calc_crc;
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guint crc_offset = tvb_reported_length(tvb)-2;
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crc = tvb_get_letohs(tvb,-2);
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/* crc includes the header */
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calc_crc = crc16_ccitt_tvb(tvb,crc_offset);
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if( crc == calc_crc ) {
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proto_tree_add_uint_format(srp_tree, hf_srp_crc, tvb,
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crc_offset, 2, crc,
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"CRC: 0x%04x (correct)", crc);
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} else {
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hidden_item = proto_tree_add_boolean(srp_tree, hf_srp_crc_bad, tvb,
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crc_offset, 2, TRUE);
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PROTO_ITEM_SET_HIDDEN(hidden_item);
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proto_tree_add_uint_format(srp_tree, hf_srp_crc, tvb,
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crc_offset, 2, crc,
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"CRC: 0x%04x (incorrect, should be 0x%04x)",
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crc,
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calc_crc);
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}
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}
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}
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void proto_register_ccsrl (void)
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{
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static hf_register_info hf[] = {
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{ &hf_ccsrl_ls,
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{ "Last Segment","ccsrl.ls",FT_UINT8, BASE_HEX, ccsrl_ls_vals, 0x0,
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"Last segment indicator", HFILL}},
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};
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static gint *ett[] = {
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&ett_ccsrl,
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};
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proto_ccsrl = proto_register_protocol ("H.324/CCSRL", "CCSRL", "ccsrl");
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proto_register_field_array (proto_ccsrl, hf, array_length (hf));
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proto_register_subtree_array (ett, array_length (ett));
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register_dissector("ccsrl", dissect_ccsrl, proto_ccsrl);
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}
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void proto_register_srp (void)
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{
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static hf_register_info hf[] = {
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{&hf_srp_header,
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{ "Header", "srp.header", FT_UINT8, BASE_DEC, srp_frame_types, 0x0,
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"SRP header octet", HFILL }},
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{&hf_srp_seqno,
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{ "Sequence Number", "srp.seqno", FT_UINT8, BASE_DEC, NULL, 0x0,
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"Sequence Number", HFILL }},
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{&hf_srp_crc,
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{ "CRC", "srp.crc", FT_UINT16, BASE_HEX, NULL, 0x0,
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"CRC", HFILL }},
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{ &hf_srp_crc_bad,
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{ "Bad CRC","srp.crc_bad", FT_BOOLEAN, BASE_NONE, NULL, 0x0,
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"", HFILL }},
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};
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static gint *ett[] = {
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&ett_srp,
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};
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proto_srp = proto_register_protocol ("H.324/SRP", "SRP", "srp");
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proto_register_field_array (proto_srp, hf, array_length (hf));
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proto_register_subtree_array (ett, array_length (ett));
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register_dissector("srp", dissect_srp, proto_srp);
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/* register our init routine to be called at the start of a capture,
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to clear out our hash tables etc */
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/* register_init_routine(&srp_init_protocol); */
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}
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void proto_reg_handoff_srp(void) {
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ccsrl_handle = find_dissector("ccsrl");
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h245dg_handle = find_dissector("h245dg");
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}
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