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wireshark/packet-v120.c
Guy Harris 231908c8a5 To determine the direction of the traffic, use "pinfo->p2p_dir", rather 
than the p2p pseudo-header's "sent" field, in the LAPD dissector (the
p2p pseudo-header isn't used for ISDN).

Do something similar for the V.120 dissector (which currently will only
be used in ISDN captures, but this makes it possible for it to handle
other captures as well).

svn path=/trunk/; revision=6522
2002-10-31 07:43:10 +00:00

231 lines
7.4 KiB
C
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/* packet-v120.c
* Routines for v120 frame disassembly
* Bert Driehuis <driehuis@playbeing.org>
*
* $Id: packet-v120.c,v 1.30 2002/10/31 07:43:10 guy Exp $
*
* Ethereal - Network traffic analyzer
* By Gerald Combs <gerald@ethereal.com>
* Copyright 1998
*
* 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 <glib.h>
#include <string.h>
#include <epan/packet.h>
#include "xdlc.h"
static int proto_v120 = -1;
static int hf_v120_address = -1;
static int hf_v120_control = -1;
static int hf_v120_header = -1;
static gint ett_v120 = -1;
static gint ett_v120_address = -1;
static gint ett_v120_control = -1;
static gint ett_v120_header = -1;
static dissector_handle_t data_handle;
static int dissect_v120_header(tvbuff_t *tvb, int offset, proto_tree *tree);
static void
dissect_v120(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
{
proto_tree *v120_tree, *tc, *address_tree;
proto_item *ti;
int is_response;
int addr;
char info[80];
int v120len;
guint8 byte0, byte1;
guint16 control;
tvbuff_t *next_tvb;
if (check_col(pinfo->cinfo, COL_PROTOCOL))
col_set_str(pinfo->cinfo, COL_PROTOCOL, "V.120");
if (check_col(pinfo->cinfo, COL_INFO))
col_clear(pinfo->cinfo, COL_INFO);
byte0 = tvb_get_guint8(tvb, 0);
if(check_col(pinfo->cinfo, COL_RES_DL_SRC))
col_add_fstr(pinfo->cinfo, COL_RES_DL_SRC, "0x%02X", byte0);
byte1 = tvb_get_guint8(tvb, 1);
if ((byte0 & 0x01) != 0x00 && (byte1 && 0x01) != 0x01)
{
if (check_col(pinfo->cinfo, COL_INFO))
col_set_str(pinfo->cinfo, COL_INFO, "Invalid V.120 frame");
if (tree)
ti = proto_tree_add_protocol_format(tree, proto_v120, tvb, 0, -1,
"Invalid V.120 frame");
return;
}
if (pinfo->p2p_dir == P2P_DIR_SENT) {
is_response = (byte0 & 0x02) ? FALSE: TRUE;
if(check_col(pinfo->cinfo, COL_RES_DL_DST))
col_set_str(pinfo->cinfo, COL_RES_DL_DST, "DCE");
if(check_col(pinfo->cinfo, COL_RES_DL_SRC))
col_set_str(pinfo->cinfo, COL_RES_DL_SRC, "DTE");
} else {
/* XXX - what if the direction is unknown? */
is_response = (byte0 & 0x02) ? TRUE : FALSE;
if(check_col(pinfo->cinfo, COL_RES_DL_DST))
col_set_str(pinfo->cinfo, COL_RES_DL_DST, "DTE");
if(check_col(pinfo->cinfo, COL_RES_DL_SRC))
col_set_str(pinfo->cinfo, COL_RES_DL_SRC, "DCE");
}
if (tree) {
ti = proto_tree_add_protocol_format(tree, proto_v120, tvb, 0, -1, "V.120");
v120_tree = proto_item_add_subtree(ti, ett_v120);
addr = byte1 << 8 | byte0;
sprintf(info, "LLI: %d C/R: %s",
((byte0 & 0xfc) << 5) | ((byte1 & 0xfe) >> 1),
byte0 & 0x02 ? "R" : "C");
tc = proto_tree_add_text(v120_tree, tvb,
0, 2,
"Address field: %s", info);
address_tree = proto_item_add_subtree(tc, ett_v120_address);
proto_tree_add_text(address_tree, tvb, 0, 2,
decode_boolean_bitfield(addr, 0x0002, 2*8,
"Response", "Command"), NULL);
sprintf(info, "LLI: %d", ((byte0 & 0xfc) << 5) | ((byte1 & 0xfe) >> 1));
proto_tree_add_text(address_tree, tvb, 0, 2,
decode_numeric_bitfield(addr, 0xfefc, 2*8, info));
proto_tree_add_text(address_tree, tvb, 0, 2,
decode_boolean_bitfield(addr, 0x0001, 2*8,
"EA0 = 1 (Error)", "EA0 = 0"), NULL);
proto_tree_add_text(address_tree, tvb, 0, 2,
decode_boolean_bitfield(addr, 0x0100, 2*8,
"EA1 = 1", "EA1 = 0 (Error)"), NULL);
}
else {
v120_tree = NULL;
ti = NULL;
}
control = dissect_xdlc_control(tvb, 2, pinfo, v120_tree, hf_v120_control,
ett_v120_control, is_response, TRUE);
if (tree) {
v120len = 2 + XDLC_CONTROL_LEN(control, TRUE);
if (tvb_bytes_exist(tvb, v120len, 1))
v120len += dissect_v120_header(tvb, v120len, v120_tree);
proto_item_set_len(ti, v120len);
next_tvb = tvb_new_subset(tvb, v120len, -1, -1);
call_dissector(data_handle,next_tvb, pinfo, v120_tree);
}
}
static int
dissect_v120_header(tvbuff_t *tvb, int offset, proto_tree *tree)
{
char info[80];
int header_len, nbits;
int header;
proto_tree *h_tree, *tc;
guint8 byte0;
byte0 = tvb_get_guint8(tvb, offset);
if (byte0 & 0x80) {
header_len = 1;
header = byte0;
} else {
header_len = 2;
header = byte0 | tvb_get_guint8(tvb, offset + 1) << 8;
}
nbits = header_len * 8;
sprintf(info, "Header: B: %d F: %d", byte0 & 0x02 ? 1:0,
byte0 & 0x01 ? 1:0);
tc = proto_tree_add_text(tree, tvb,
offset, header_len,
"Header octet: %s (0x%02X)", info, byte0);
h_tree = proto_item_add_subtree(tc, ett_v120_header);
proto_tree_add_text(h_tree, tvb, offset, header_len,
decode_boolean_bitfield(header, 0x80, nbits,
"No extension octet", "Extension octet follows"), NULL);
proto_tree_add_text(h_tree, tvb, offset, header_len,
decode_boolean_bitfield(header, 0x40, nbits,
"Break condition", "No break condition"), NULL);
sprintf(info, "Error control C1/C2: %d", (header & 0x0c) >> 2);
proto_tree_add_text(h_tree, tvb, offset, header_len,
decode_numeric_bitfield(header, 0x0c, nbits, info));
proto_tree_add_text(h_tree, tvb, offset, header_len,
decode_boolean_bitfield(header, 0x02, nbits,
"Segmentation bit B", "No segmentation bit B"), NULL);
proto_tree_add_text(h_tree, tvb, offset, header_len,
decode_boolean_bitfield(header, 0x01, nbits,
"Segmentation bit F", "No segmentation bit F"), NULL);
if (header_len == 2) {
proto_tree_add_text(h_tree, tvb, offset, header_len,
decode_boolean_bitfield(header, 0x8000, nbits,
"E", "E bit not set (Error)"), NULL);
proto_tree_add_text(h_tree, tvb, offset, header_len,
decode_boolean_bitfield(header, 0x4000, nbits,
"DR", "No DR"), NULL);
proto_tree_add_text(h_tree, tvb, offset, header_len,
decode_boolean_bitfield(header, 0x2000, nbits,
"SR", "No SR"), NULL);
proto_tree_add_text(h_tree, tvb, offset, header_len,
decode_boolean_bitfield(header, 0x1000, nbits,
"RR", "No RR"), NULL);
}
return header_len;
}
void
proto_register_v120(void)
{
static hf_register_info hf[] = {
{ &hf_v120_address,
{ "Link Address", "v120.address", FT_UINT16, BASE_HEX, NULL,
0x0, "", HFILL }},
{ &hf_v120_control,
{ "Control Field", "v120.control", FT_UINT16, BASE_HEX, NULL, 0x0,
"", HFILL }},
{ &hf_v120_header,
{ "Header Field", "v120.header", FT_STRING, BASE_NONE, NULL, 0x0,
"", HFILL }},
};
static gint *ett[] = {
&ett_v120,
&ett_v120_address,
&ett_v120_control,
&ett_v120_header,
};
proto_v120 = proto_register_protocol("Async data over ISDN (V.120)",
"V.120", "v120");
proto_register_field_array (proto_v120, hf, array_length(hf));
proto_register_subtree_array(ett, array_length(ett));
register_dissector("v120", dissect_v120, proto_v120);
}
void
proto_reg_handoff_v120(void)
{
data_handle = find_dissector("data");
}
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