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/* packet-socketcan.c
* Routines for disassembly of packets from SocketCAN
* Felix Obenhuber <felix@obenhuber.de>
*
* $Id$
*
* 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 <glib.h>
#include <epan/packet.h>
#include <prefs.h>
#include "packet-sll.h"
/* controller area network (CAN) kernel definitions
* These masks are usually defined within <linux/can.h> but are not
* available on non-Linux platforms; that's the reason for the
* redefinitions below
*
* special address description flags for the CAN_ID */
#define CAN_EFF_FLAG 0x80000000U /* EFF/SFF is set in the MSB */
#define CAN_RTR_FLAG 0x40000000U /* remote transmission request */
#define CAN_ERR_FLAG 0x20000000U /* error frame */
#define CAN_EFF_MASK 0x1FFFFFFFU /* extended frame format (EFF) */
static int hf_can_len = -1;
static int hf_can_ident = -1;
static int hf_can_extflag = -1;
static int hf_can_rtrflag = -1;
static int hf_can_errflag = -1;
static gint ett_can = -1;
static int proto_can = -1;
static dissector_handle_t data_handle;
static dissector_handle_t canopen_handle;
#define LINUX_CAN_STD 0
#define LINUX_CAN_EXT 1
#define LINUX_CAN_RTR 2
#define LINUX_CAN_ERR 3
#define CAN_LEN_OFFSET 4
#define CAN_DATA_OFFSET 8
typedef enum {
CAN_DATA_DISSECTOR = 1,
CAN_CANOPEN_DISSECTOR = 2
} Dissector_Option;
static enum_val_t can_high_level_protocol_dissector_options[] = {
{ "raw", "Raw data (no further dissection)", CAN_DATA_DISSECTOR },
{ "CANopen", "CANopen protocol", CAN_CANOPEN_DISSECTOR },
{ NULL, NULL, 0 }
};
static guint can_high_level_protocol_dissector = CAN_DATA_DISSECTOR;
static const value_string frame_type_vals[] =
{
{ LINUX_CAN_STD, "STD" },
{ LINUX_CAN_EXT, "XTD" },
{ LINUX_CAN_RTR, "RTR" },
{ LINUX_CAN_ERR, "ERR" },
{ 0, NULL }
};
static void
dissect_socketcan(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
{
proto_tree *can_tree;
proto_item *ti;
guint8 frame_type;
gint frame_len;
guint32 id;
col_set_str(pinfo->cinfo, COL_PROTOCOL, "CAN");
col_clear(pinfo->cinfo,COL_INFO);
frame_len = tvb_get_guint8( tvb, CAN_LEN_OFFSET);
id = tvb_get_ntohl(tvb, 0);
if (id & CAN_RTR_FLAG)
{
frame_type = LINUX_CAN_RTR;
}
else if (id & CAN_ERR_FLAG)
{
frame_type = LINUX_CAN_ERR;
}
else if (id & CAN_EFF_FLAG)
{
frame_type = LINUX_CAN_EXT;
}
else
{
frame_type = LINUX_CAN_STD;
}
id &= CAN_EFF_MASK;
col_add_fstr(pinfo->cinfo, COL_INFO, "%s: 0x%08x",
val_to_str(frame_type, frame_type_vals, "Unknown (0x%02x)"), id);
col_append_fstr(pinfo->cinfo, COL_INFO, " %s",
tvb_bytes_to_str_punct(tvb, CAN_DATA_OFFSET, frame_len, ' '));
ti = proto_tree_add_item(tree, proto_can, tvb, 0, -1, ENC_NA);
can_tree = proto_item_add_subtree(ti, ett_can);
proto_tree_add_item(can_tree, hf_can_ident, tvb, 0, 4, ENC_BIG_ENDIAN);
proto_tree_add_item(can_tree, hf_can_extflag, tvb, 0, 4, ENC_BIG_ENDIAN);
proto_tree_add_item(can_tree, hf_can_rtrflag, tvb, 0, 4, ENC_BIG_ENDIAN);
proto_tree_add_item(can_tree, hf_can_errflag, tvb, 0, 4, ENC_BIG_ENDIAN);
proto_tree_add_item(can_tree, hf_can_len, tvb, CAN_LEN_OFFSET, 1, ENC_BIG_ENDIAN);
switch (can_high_level_protocol_dissector)
{
case CAN_DATA_DISSECTOR:
call_dissector(data_handle,
tvb_new_subset(tvb, CAN_DATA_OFFSET, frame_len, frame_len),
pinfo, tree);
break;
case CAN_CANOPEN_DISSECTOR:
/* XXX: The canopen dissector *redissects in a different manner* */
/* the same header bytes dissected above. */
/* What's the right way to handle SocketCan dissection ? */
call_dissector(canopen_handle, tvb, pinfo, tree);
break;
}
}
void
proto_register_socketcan(void)
{
static hf_register_info hf[] = {
{
&hf_can_ident,
{
"Identifier", "can.id",
FT_UINT32, BASE_HEX,
NULL, CAN_EFF_MASK,
NULL, HFILL
}
},
{
&hf_can_extflag,
{
"Extended Flag", "can.flags.xtd",
FT_BOOLEAN, 32,
NULL, CAN_EFF_FLAG,
NULL, HFILL
}
},
{
&hf_can_rtrflag,
{
"Remote Transmission Request Flag", "can.flags.rtr",
FT_BOOLEAN, 32,
NULL, CAN_RTR_FLAG,
NULL, HFILL
}
},
{
&hf_can_errflag,
{
"Error Flag", "can.flags.err",
FT_BOOLEAN, 32,
NULL, CAN_ERR_FLAG,
NULL, HFILL
}
},
{
&hf_can_len,
{
"Frame-Length", "can.len",
FT_UINT8, BASE_DEC,
NULL, 0x0,
NULL, HFILL
}
}
};
/* Setup protocol subtree array */
static gint *ett[] =
{
&ett_can
};
module_t *can_module;
proto_can = proto_register_protocol(
"Controller Area Network", /* name */
"CAN", /* short name */
"can" /* abbrev */
);
proto_register_field_array(proto_can, hf, array_length(hf));
proto_register_subtree_array(ett, array_length(ett));
can_module = prefs_register_protocol(proto_can, NULL);
prefs_register_enum_preference(
can_module,
"protocol",
"Next level protocol",
"Next level protocol like CANopen etc.",
(gint *)&can_high_level_protocol_dissector,
can_high_level_protocol_dissector_options,
FALSE
);
}
void
proto_reg_handoff_socketcan(void)
{
dissector_handle_t can_handle;
can_handle = create_dissector_handle(dissect_socketcan, proto_can);
dissector_add_uint("wtap_encap", WTAP_ENCAP_SOCKETCAN, can_handle);
dissector_add_uint("sll.ltype", LINUX_SLL_P_CAN, can_handle);
canopen_handle = find_dissector("canopen");
data_handle = find_dissector("data");
}
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