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wireshark/epan/dissectors/packet-rmt-alc.c

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/* packet-rmt-alc.c
* Reliable Multicast Transport (RMT)
* ALC Protocol Instantiation dissector
* Copyright 2005, Stefano Pettini <spettini@users.sourceforge.net>
*
* Asynchronous Layered Coding (ALC):
* ----------------------------------
*
* A massively scalable reliable content delivery protocol.
* Asynchronous Layered Coding combines the Layered Coding Transport
* (LCT) building block, a multiple rate congestion control building
* block and the Forward Error Correction (FEC) building block to
* provide congestion controlled reliable asynchronous delivery of
* content to an unlimited number of concurrent receivers from a single
* sender.
*
* References:
* RFC 3450, Asynchronous Layered Coding protocol instantiation
*
* $Id$
*
* 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 <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <glib.h>
#include <epan/packet.h>
#include <epan/prefs.h>
#include "packet-rmt-alc.h"
/* Initialize the protocol and registered fields */
/* ============================================= */
static int proto = -1;
static struct _alc_hf hf;
static struct _alc_ett ett;
static struct _alc_prefs preferences;
dissector_handle_t xml_handle;
/* Preferences */
/* =========== */
/* Set/Reset preferences to default values */
static void alc_prefs_set_default(struct _alc_prefs *prefs)
{
prefs->use_default_udp_port = FALSE;
prefs->default_udp_port = 4001;
lct_prefs_set_default(&prefs->lct);
fec_prefs_set_default(&prefs->fec);
}
/* Register preferences */
static void alc_prefs_register(struct _alc_prefs *prefs, module_t *module)
{
prefs_register_bool_preference(module,
"default.udp_port.enabled",
"Use default UDP port",
"Whether that payload of UDP packets with a specific destination port should be automatically dissected as ALC packets",
&prefs->use_default_udp_port);
prefs_register_uint_preference(module,
"default.udp_port",
"Default UDP destination port",
"Specifies the UDP destination port for automatic dissection of ALC packets",
10, &prefs->default_udp_port);
lct_prefs_register(&prefs->lct, module);
fec_prefs_register(&prefs->fec, module);
}
/* Save preferences to alc_prefs_old */
static void alc_prefs_save(struct _alc_prefs *p, struct _alc_prefs *p_old)
{
*p_old = *p;
}
/* Code to actually dissect the packets */
/* ==================================== */
static void dissect_alc(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
{
/* Logical packet representation */
struct _alc alc;
/* Offset for subpacket dissection */
guint offset;
/* Set up structures needed to add the protocol subtree and manage it */
proto_item *ti;
proto_tree *alc_tree;
/* Flute or not */
tvbuff_t *new_tvb;
gboolean is_flute = FALSE;
/* Structures and variables initialization */
offset = 0;
memset(&alc, 0, sizeof(struct _alc));
/* Update packet info */
pinfo->current_proto = "ALC";
/* Make entries in Protocol column and Info column on summary display */
if (check_col(pinfo->cinfo, COL_PROTOCOL))
col_set_str(pinfo->cinfo, COL_PROTOCOL, "ALC");
if (check_col(pinfo->cinfo, COL_INFO))
col_clear(pinfo->cinfo, COL_INFO);
/* ALC header dissection */
/* --------------------- */
alc.version = hi_nibble(tvb_get_guint8(tvb, offset));
if (tree)
{
/* Create subtree for the ALC protocol */
ti = proto_tree_add_item(tree, proto, tvb, offset, -1, FALSE);
alc_tree = proto_item_add_subtree(ti, ett.main);
/* Fill the ALC subtree */
proto_tree_add_uint(alc_tree, hf.version, tvb, offset, 1, alc.version);
} else
alc_tree = NULL;
/* This dissector supports only ALCv1 packets.
* If alc.version > 1 print only version field and quit.
*/
if (alc.version == 1) {
struct _lct_ptr l;
struct _fec_ptr f;
l.lct = &alc.lct;
l.hf = &hf.lct;
l.ett = &ett.lct;
l.prefs = &preferences.lct;
f.fec = &alc.fec;
f.hf = &hf.fec;
f.ett = &ett.fec;
f.prefs = &preferences.fec;
/* LCT header dissection */
/* --------------------- */
is_flute = lct_dissector(l, f, tvb, alc_tree, &offset);
/* FEC header dissection */
/* --------------------- */
/* Only if it's present and if LCT dissector has determined FEC Encoding ID
* FEC dissector should be called with fec->encoding_id* and fec->instance_id* filled
*/
if (alc.fec.encoding_id_present && tvb_length(tvb) > offset)
fec_dissector(f, tvb, alc_tree, &offset);
/* Add the Payload item */
if (tvb_length(tvb) > offset){
if(is_flute){
new_tvb = tvb_new_subset(tvb,offset,-1,-1);
call_dissector(xml_handle, new_tvb, pinfo, alc_tree);
}else{
proto_tree_add_none_format(alc_tree, hf.payload, tvb, offset, -1, "Payload (%u bytes)", tvb_length(tvb) - offset);
}
}
/* Complete entry in Info column on summary display */
/* ------------------------------------------------ */
if (check_col(pinfo->cinfo, COL_INFO))
{
lct_info_column(&alc.lct, pinfo);
fec_info_column(&alc.fec, pinfo);
}
/* Free g_allocated memory */
lct_dissector_free(&alc.lct);
fec_dissector_free(&alc.fec);
} else {
if (tree)
proto_tree_add_text(alc_tree, tvb, 0, -1, "Sorry, this dissector supports ALC version 1 only");
/* Complete entry in Info column on summary display */
if (check_col(pinfo->cinfo, COL_INFO))
col_add_fstr(pinfo->cinfo, COL_INFO, "Version: %u (not supported)", alc.version);
}
}
void proto_reg_handoff_alc(void)
{
static dissector_handle_t handle;
static gboolean preferences_initialized = FALSE;
static struct _alc_prefs preferences_old;
if (!preferences_initialized)
{
preferences_initialized = TRUE;
handle = create_dissector_handle(dissect_alc, proto);
dissector_add_handle("udp.port", handle);
xml_handle = find_dissector("xml");
} else {
if (preferences_old.use_default_udp_port)
dissector_delete("udp.port", preferences_old.default_udp_port, handle);
}
if (preferences.use_default_udp_port)
dissector_add("udp.port", preferences.default_udp_port, handle);
alc_prefs_save(&preferences, &preferences_old);
}
void proto_register_alc(void)
{
/* Setup ALC header fields */
static hf_register_info hf_ptr[] = {
{ &hf.version,
{ "Version", "alc.version", FT_UINT8, BASE_DEC, NULL, 0x0, "", HFILL }},
LCT_FIELD_ARRAY(hf.lct, "alc"),
FEC_FIELD_ARRAY(hf.fec, "alc"),
{ &hf.payload,
{ "Payload", "alc.payload", FT_NONE, BASE_NONE, NULL, 0x0, "", HFILL }}
};
/* Setup protocol subtree array */
static gint *ett_ptr[] = {
&ett.main,
LCT_SUBTREE_ARRAY(ett.lct),
FEC_SUBTREE_ARRAY(ett.fec)
};
module_t *module;
/* Clear hf and ett fields */
memset(&hf, 0xff, sizeof(struct _alc_hf));
memset(&ett, 0xff, sizeof(struct _alc_ett));
/* Register the protocol name and description */
proto = proto_register_protocol("Asynchronous Layered Coding", "ALC", "alc");
/* Register the header fields and subtrees used */
proto_register_field_array(proto, hf_ptr, array_length(hf_ptr));
proto_register_subtree_array(ett_ptr, array_length(ett_ptr));
/* Reset preferences */
alc_prefs_set_default(&preferences);
/* Register preferences */
module = prefs_register_protocol(proto, proto_reg_handoff_alc);
alc_prefs_register(&preferences, module);
}
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