Wireshark-dev: [Wireshark-dev] New packet disassembly module
From: Sean Sheedy <seansh@xxxxxxxxxxxxxxxxxxxxx>
Date: Fri, 14 Jul 2006 13:34:59 -0700
Attached is a packet disassembly module I wrote for Pegasus Lightweight Stream Control, a protocol used by some cable set-top boxes for video-on-demand. I would appreciate it being added to the source base. Thanks. Sean -- Sean Sheedy seansh@users.sourceforge.net1
/* packet-lsc.c
* Routines for Pegasus LSC packet disassembly
* Copyright 2006, Sean Sheedy <seansh@xxxxxxxxxxxxxxxxxxxxx>
*
* $Id$
*
* Ethereal - Network traffic analyzer
* By Gerald Combs <gerald@xxxxxxxxxxxx>
* 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/emem.h>
#include <epan/prefs.h>
#include <packet-tcp.h>
/* Forward declaration we need below */
void proto_reg_handoff_lsc(void);
#define LSC_PAUSE 0x01
#define LSC_RESUME 0x02
#define LSC_STATUS 0x03
#define LSC_RESET 0x04
#define LSC_JUMP 0x05
#define LSC_PLAY 0x06
#define LSC_DONE 0x40
#define LSC_PAUSE_REPLY 0x81
#define LSC_RESUME_REPLY 0x82
#define LSC_STATUS_REPLY 0x83
#define LSC_RESET_REPLY 0x84
#define LSC_JUMP_REPLY 0x85
#define LSC_PLAY_REPLY 0x86
#define isReply(o) ((o) & 0x80)
static const value_string op_code_vals[] = {
{ LSC_PAUSE, "LSC_PAUSE" },
{ LSC_RESUME, "LSC_RESUME" },
{ LSC_STATUS, "LSC_STATUS" },
{ LSC_RESET, "LSC_RESET" },
{ LSC_JUMP, "LSC_JUMP" },
{ LSC_PLAY, "LSC_PLAY" },
{ LSC_DONE, "LSC_DONE" },
{ LSC_PAUSE_REPLY, "LSC_PAUSE_REPLY" },
{ LSC_RESUME_REPLY, "LSC_RESUME_REPLY" },
{ LSC_STATUS_REPLY, "LSC_STATUS_REPLY" },
{ LSC_RESET_REPLY, "LSC_RESET_REPLY" },
{ LSC_JUMP_REPLY, "LSC_JUMP_REPLY" },
{ LSC_PLAY_REPLY, "LSC_PLAY_REPLY" },
{ 0, NULL }
};
#define LSC_OPCODE_LEN 3 /* Length to find op code */
#define LSC_MIN_LEN 8 /* Minimum packet length */
/* Length of each packet type */
#define LSC_PAUSE_LEN 12
#define LSC_RESUME_LEN 16
#define LSC_STATUS_LEN 8
#define LSC_RESET_LEN 8
#define LSC_JUMP_LEN 20
#define LSC_PLAY_LEN 20
#define LSC_REPLY_LEN 17
static const value_string status_code_vals[] = {
{ 0x00, "LSC_OK" },
{ 0x10, "LSC_BAD_REQUEST" },
{ 0x11, "LSC_BAD_STREAM" },
{ 0x12, "LSC_WRONG_STATE" },
{ 0x13, "LSC_UNKNOWN" },
{ 0x14, "LSC_NO_PERMISSION" },
{ 0x15, "LSC_BAD_PARAM" },
{ 0x16, "LSC_NO_IMPLEMENT" },
{ 0x17, "LSC_NO_MEMORY" },
{ 0x18, "LSC_IMP_LIMIT" },
{ 0x19, "LSC_TRANSIENT" },
{ 0x1a, "LSC_NO_RESOURCES" },
{ 0x20, "LSC_SERVER_ERROR" },
{ 0x21, "LSC_SERVER_FAILURE" },
{ 0x30, "LSC_BAD_SCALE" },
{ 0x31, "LSC_BAD_START" },
{ 0x32, "LSC_BAD_STOP" },
{ 0x40, "LSC_MPEG_DELIVERY" },
{ 0, NULL }
};
static const value_string mode_vals[] = {
{ 0x00, "O - Open Mode" },
{ 0x01, "P - Pause Mode" },
{ 0x02, "ST - Search Transport" },
{ 0x03, "T - Transport" },
{ 0x04, "TP - Transport Pause" },
{ 0x05, "STP - Search Transport Pause" },
{ 0x06, "PST - Pause Search Transport" },
{ 0x07, "EOS - End of Stream" },
{ 0, NULL }
};
/* Initialize the protocol and registered fields */
static int proto_lsc = -1;
static int hf_lsc_version = -1;
static int hf_lsc_trans_id = -1;
static int hf_lsc_op_code = -1;
static int hf_lsc_status_code = -1;
static int hf_lsc_stream_handle = -1;
static int hf_lsc_start_npt = -1;
static int hf_lsc_stop_npt = -1;
static int hf_lsc_current_npt = -1;
static int hf_lsc_scale_num = -1;
static int hf_lsc_scale_denom = -1;
static int hf_lsc_mode = -1;
/* Preferences */
static guint global_lsc_port = 0;
static guint lsc_port = 0;
/* Initialize the subtree pointers */
static gint ett_lsc = -1;
/* Code to actually dissect the packets */
static void
dissect_lsc_common(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
{
proto_item *ti;
proto_tree *lsc_tree;
guint8 op_code;
guint32 stream;
guint expected_len;
/* Protocol is LSC, packet summary is not yet known */
if (check_col(pinfo->cinfo, COL_PROTOCOL))
col_set_str(pinfo->cinfo, COL_PROTOCOL, "LSC");
if (check_col(pinfo->cinfo, COL_INFO))
col_clear(pinfo->cinfo, COL_INFO);
/* Too little data? */
if (tvb->length < LSC_MIN_LEN)
{
if (check_col(pinfo->cinfo, COL_INFO))
col_set_str(pinfo->cinfo, COL_INFO, "[Too short]");
return;
}
/* Get the op code */
op_code = tvb_get_guint8(tvb, 2);
/* And the stream handle */
stream = tvb_get_ntohl(tvb, 4);
/* Check the data length against what we actually received */
switch (op_code)
{
case LSC_PAUSE:
expected_len = LSC_PAUSE_LEN;
break;
case LSC_RESUME:
expected_len = LSC_RESUME_LEN;
break;
case LSC_STATUS:
expected_len = LSC_STATUS_LEN;
break;
case LSC_RESET:
expected_len = LSC_RESET_LEN;
break;
case LSC_JUMP:
expected_len = LSC_JUMP_LEN;
break;
case LSC_PLAY:
expected_len = LSC_PLAY_LEN;
break;
case LSC_DONE:
case LSC_PAUSE_REPLY:
case LSC_RESUME_REPLY:
case LSC_STATUS_REPLY:
case LSC_RESET_REPLY:
case LSC_JUMP_REPLY:
case LSC_PLAY_REPLY:
expected_len = LSC_REPLY_LEN;
break;
default:
/* Unrecognized op code */
expected_len = LSC_MIN_LEN;
break;
}
/* Display the op code in the summary */
if (check_col(pinfo->cinfo, COL_INFO)) {
col_add_fstr(pinfo->cinfo, COL_INFO, "%s, session %.8u",
val_to_str(op_code, op_code_vals, "Unknown op code (0x%x)"),
stream);
if (tvb->length < expected_len)
col_append_str(pinfo->cinfo, COL_INFO, " [Too short]");
else if (tvb->length > expected_len)
col_append_str(pinfo->cinfo, COL_INFO, " [Too long]");
}
if (tree) {
/* Create display subtree for the protocol */
ti = proto_tree_add_item(tree, proto_lsc, tvb, 0, -1, FALSE);
lsc_tree = proto_item_add_subtree(ti, ett_lsc);
/* Add already fetched items to the tree */
proto_tree_add_uint(lsc_tree, hf_lsc_op_code, tvb, 2, 1, op_code);
proto_tree_add_uint_format_value(lsc_tree, hf_lsc_stream_handle, tvb, 4, 4,
stream, "%.8u", stream);
/* Add rest of LSC header */
proto_tree_add_uint(lsc_tree, hf_lsc_version, tvb, 0, 1,
tvb_get_guint8(tvb, 0));
proto_tree_add_uint(lsc_tree, hf_lsc_trans_id, tvb, 1, 1,
tvb_get_guint8(tvb, 1));
/* Only replies contain a status code */
if (isReply(op_code))
proto_tree_add_uint(lsc_tree, hf_lsc_status_code, tvb, 3, 1,
tvb_get_guint8(tvb, 3));
/* Add op code specific parts */
switch (op_code)
{
case LSC_PAUSE:
proto_tree_add_int(lsc_tree, hf_lsc_stop_npt, tvb, 8, 4,
tvb_get_ntohl(tvb, 8));
break;
case LSC_RESUME:
proto_tree_add_int(lsc_tree, hf_lsc_start_npt, tvb, 8, 4,
tvb_get_ntohl(tvb, 8));
proto_tree_add_int(lsc_tree, hf_lsc_scale_num, tvb, 12, 2,
tvb_get_ntohs(tvb, 12));
proto_tree_add_uint(lsc_tree, hf_lsc_scale_denom, tvb, 14, 2,
tvb_get_ntohs(tvb, 14));
break;
case LSC_JUMP:
case LSC_PLAY:
proto_tree_add_int(lsc_tree, hf_lsc_start_npt, tvb, 8, 4,
tvb_get_ntohl(tvb, 8));
proto_tree_add_int(lsc_tree, hf_lsc_stop_npt, tvb, 12, 4,
tvb_get_ntohl(tvb, 12));
proto_tree_add_int(lsc_tree, hf_lsc_scale_num, tvb, 16, 2,
tvb_get_ntohs(tvb, 16));
proto_tree_add_uint(lsc_tree, hf_lsc_scale_denom, tvb, 18, 2,
tvb_get_ntohs(tvb, 18));
break;
case LSC_DONE:
case LSC_PAUSE_REPLY:
case LSC_RESUME_REPLY:
case LSC_STATUS_REPLY:
case LSC_RESET_REPLY:
case LSC_JUMP_REPLY:
case LSC_PLAY_REPLY:
proto_tree_add_int(lsc_tree, hf_lsc_current_npt, tvb, 8, 4,
tvb_get_ntohl(tvb, 8));
proto_tree_add_int(lsc_tree, hf_lsc_scale_num, tvb, 12, 2,
tvb_get_ntohs(tvb, 12));
proto_tree_add_uint(lsc_tree, hf_lsc_scale_denom, tvb, 14, 2,
tvb_get_ntohs(tvb, 14));
proto_tree_add_uint(lsc_tree, hf_lsc_mode, tvb, 16, 1,
tvb_get_guint8(tvb, 16));
break;
default:
break;
}
}
}
/* Decode LSC over UDP */
static void
dissect_lsc_udp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
{
dissect_lsc_common(tvb, pinfo, tree);
}
/* Determine length of LSC message */
static guint
get_lsc_pdu_len(tvbuff_t *tvb, int offset)
{
guint8 op_code;
guint pdu_len;
/* Get the op code */
op_code = tvb_get_guint8(tvb, offset + 2);
switch (op_code)
{
case LSC_PAUSE:
pdu_len = LSC_PAUSE_LEN;
break;
case LSC_RESUME:
pdu_len = LSC_RESUME_LEN;
break;
case LSC_STATUS:
pdu_len = LSC_STATUS_LEN;
break;
case LSC_RESET:
pdu_len = LSC_RESET_LEN;
break;
case LSC_JUMP:
pdu_len = LSC_JUMP_LEN;
break;
case LSC_PLAY:
pdu_len = LSC_PLAY_LEN;
break;
case LSC_DONE:
case LSC_PAUSE_REPLY:
case LSC_RESUME_REPLY:
case LSC_STATUS_REPLY:
case LSC_RESET_REPLY:
case LSC_JUMP_REPLY:
case LSC_PLAY_REPLY:
pdu_len = LSC_REPLY_LEN;
break;
default:
/* Unrecognized op code */
pdu_len = LSC_OPCODE_LEN;
break;
}
return pdu_len;
}
/* Decode LSC over TCP */
static void
dissect_lsc_tcp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
{
tcp_dissect_pdus(tvb, pinfo, tree, TRUE, LSC_OPCODE_LEN, get_lsc_pdu_len,
dissect_lsc_common);
}
/* Register the protocol with Ethereal */
void
proto_register_lsc(void)
{
module_t *lsc_module;
/* Setup list of header fields */
static hf_register_info hf[] = {
{ &hf_lsc_version,
{ "Version", "lsc.version",
FT_UINT8, BASE_DEC, NULL, 0,
"Version of the Pegasus LSC protocol", HFILL }
},
{ &hf_lsc_trans_id,
{ "Transaction ID", "lsc.trans_id",
FT_UINT8, BASE_DEC, NULL, 0,
"Transaction ID", HFILL }
},
{ &hf_lsc_op_code,
{ "Op Code", "lsc.op_code",
FT_UINT8, BASE_HEX, VALS(op_code_vals), 0,
"Operation Code", HFILL }
},
{ &hf_lsc_status_code,
{ "Status Code", "lsc.status_code",
FT_UINT8, BASE_HEX, VALS(status_code_vals), 0,
"Status Code", HFILL }
},
{ &hf_lsc_stream_handle,
{ "Stream Handle", "lsc.stream_handle",
FT_UINT32, BASE_DEC, NULL, 0,
"Stream identification handle", HFILL }
},
{ &hf_lsc_start_npt,
{ "Start NPT", "lsc.start_npt",
FT_INT32, BASE_DEC, NULL, 0,
"Start Time (milliseconds)", HFILL }
},
{ &hf_lsc_stop_npt,
{ "Stop NPT", "lsc.stop_npt",
FT_INT32, BASE_DEC, NULL, 0,
"Stop Time (milliseconds)", HFILL }
},
{ &hf_lsc_current_npt,
{ "Current NPT", "lsc.current_npt",
FT_INT32, BASE_DEC, NULL, 0,
"Current Time (milliseconds)", HFILL }
},
{ &hf_lsc_scale_num,
{ "Scale Numerator", "lsc.scale_num",
FT_INT16, BASE_DEC, NULL, 0,
"Scale Numerator", HFILL }
},
{ &hf_lsc_scale_denom,
{ "Scale Denominator", "lsc.scale_denum",
FT_UINT16, BASE_DEC, NULL, 0,
"Scale Denominator", HFILL }
},
{ &hf_lsc_mode,
{ "Server Mode", "lsc.mode",
FT_UINT8, BASE_HEX, VALS(mode_vals), 0,
"Current Server Mode", HFILL }
}
};
/* Setup protocol subtree array */
static gint *ett[] = {
&ett_lsc,
};
/* Register the protocol name and description */
proto_lsc = proto_register_protocol("Pegasus Lightweight Stream Control",
"LSC", "lsc");
/* Required function calls to register the header fields and subtrees used */
proto_register_field_array(proto_lsc, hf, array_length(hf));
proto_register_subtree_array(ett, array_length(ett));
/* Register preferences module */
lsc_module = prefs_register_protocol(proto_lsc, proto_reg_handoff_lsc);
/* Register preferences */
prefs_register_uint_preference(lsc_module, "port",
"LSC Port",
"Set the TCP or UDP port for Pegasus LSC messages",
10, &global_lsc_port);
}
void
proto_reg_handoff_lsc(void)
{
dissector_handle_t lsc_udp_handle;
dissector_handle_t lsc_tcp_handle;
lsc_udp_handle = create_dissector_handle(dissect_lsc_udp, proto_lsc);
lsc_tcp_handle = create_dissector_handle(dissect_lsc_tcp, proto_lsc);
/* Set the port number */
lsc_port = global_lsc_port;
dissector_add("udp.port", lsc_port, lsc_udp_handle);
dissector_add("tcp.port", lsc_port, lsc_tcp_handle);
}
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