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/* packet-at.c
* Dissector for AT Commands
*
* Copyright 2011, Tyson Key <tyson.key@gmail.com>
*
* $Id$
*
* 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*
*/
#include "config.h"
#include <glib.h>
#include <epan/packet.h>
#include <ctype.h>
static int proto_at = -1;
static int hf_at_command = -1;
/* Forward-declare the dissector functions */
static void dissect_at(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree);
/* Subtree handles: set by register_subtree_array */
static gint ett_at = -1;
static gboolean allowed_chars(tvbuff_t *tvb)
{
gint offset, len;
guint8 val;
len = tvb_length(tvb);
for (offset = 0; offset < len; offset++) {
val = tvb_get_guint8(tvb, offset);
if (!(isprint(val) || (val == 0x0a) || (val == 0x0d)))
return (FALSE);
}
return (TRUE);
}
/* Experimental approach based upon the one used for PPP */
static gboolean heur_dissect_at(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data _U_)
{
const gchar at_magic1[2] = {0x0d, 0x0a};
const gchar at_magic2[3] = {0x0d, 0x0d, 0x0a};
const gchar at_magic3[2] = {'A', 'T'};
if (((tvb_memeql(tvb, 0, at_magic1, sizeof(at_magic1)) == 0) ||
(tvb_memeql(tvb, 0, at_magic2, sizeof(at_magic2)) == 0) ||
(tvb_memeql(tvb, 0, at_magic3, sizeof(at_magic3)) == 0)) &&
allowed_chars(tvb)) {
dissect_at(tvb, pinfo, tree);
return (TRUE);
}
return (FALSE);
}
/* The dissector itself */
static void dissect_at(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
{
proto_item *item;
proto_tree *at_tree;
gint len;
len = tvb_reported_length(tvb);
col_append_str(pinfo->cinfo, COL_PROTOCOL, "/AT");
col_append_sep_fstr(pinfo->cinfo, COL_INFO, NULL, "AT Command: %s",
tvb_format_text_wsp(tvb, 0, len));
if (tree) {
/* Start with a top-level item to add everything else to */
item = proto_tree_add_item(tree, proto_at, tvb, 0, -1, ENC_NA);
at_tree = proto_item_add_subtree(item, ett_at);
/* Command */
proto_tree_add_item(at_tree, hf_at_command, tvb, 0, len, ENC_ASCII|ENC_NA);
proto_item_append_text(item, ": %s", tvb_format_text_wsp(tvb, 0, len));
}
}
void
proto_register_at_command(void)
{
static hf_register_info hf[] = {
{ &hf_at_command,
{ "AT Command", "at.command", FT_STRING, BASE_NONE,
NULL, 0x0, NULL, HFILL }}
};
static gint *ett[] = {
&ett_at
};
proto_at = proto_register_protocol("AT Command", "AT", "at");
proto_register_field_array(proto_at, hf, array_length(hf));
proto_register_subtree_array(ett, array_length(ett));
register_dissector("at", dissect_at, proto_at);
}
/* Handler registration */
void
proto_reg_handoff_at_command(void)
{
heur_dissector_add("usb.bulk", heur_dissect_at, proto_at);
heur_dissector_add("usb.control", heur_dissect_at, proto_at);
}
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