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wireshark/epan/dissectors/packet-socketcan.c

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/* packet-socketcan.c
* Routines for disassembly of packets from SocketCAN
* Felix Obenhuber <felix@obenhuber.de>
*
* Added support for the DeviceNet Dissector
* Hans-Joergen Gunnarsson <hag@hms.se>
* Copyright 2013
*
* 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 <epan/packet.h>
#include <epan/prefs.h>
#include <epan/decode_as.h>
#include <wiretap/wtap.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 0x80000000 /* EFF/SFF is set in the MSB */
#define CAN_RTR_FLAG 0x40000000 /* remote transmission request */
#define CAN_ERR_FLAG 0x20000000 /* error frame */
#define CAN_EFF_MASK 0x1FFFFFFF /* extended frame format (EFF) */
#define CAN_SFF_MASK 0x000007FF /* standard frame format (SFF) */
void proto_register_socketcan(void);
void proto_reg_handoff_socketcan(void);
static int hf_can_len = -1;
static int hf_can_ident_ext = -1;
static int hf_can_ident_std = -1;
static int hf_can_extflag = -1;
static int hf_can_rtrflag = -1;
static int hf_can_errflag = -1;
static int hf_can_reserved = -1;
static int hf_can_padding = -1;
static int hf_canfd_brsflag = -1;
static int hf_canfd_esiflag = -1;
static gint ett_can = -1;
static gint ett_can_fd = -1;
static int proto_can = -1;
static int proto_canfd = -1;
static gboolean byte_swap = FALSE;
#define LINUX_CAN_STD 0
#define LINUX_CAN_EXT 1
#define LINUX_CAN_ERR 2
#define CAN_LEN_OFFSET 4
#define CAN_DATA_OFFSET 8
#define CANFD_FLAG_OFFSET 5
#define CANFD_BRS 0x01 /* bit rate switch (second bitrate for payload data) */
#define CANFD_ESI 0x02 /* error state indicator of the transmitting node */
/* Structure that gets passed between dissectors. Since it's just a simple 32-bit
value, no sense in creating a header file for it. Just expect subdissectors
to provide their own.
*/
struct can_identifier
{
guint32 id;
};
static dissector_table_t subdissector_table;
static dissector_handle_t socketcan_bigendian_handle;
static dissector_handle_t socketcan_hostendian_handle;
static dissector_handle_t socketcan_fd_handle;
static const value_string frame_type_vals[] =
{
{ LINUX_CAN_STD, "STD" },
{ LINUX_CAN_EXT, "XTD" },
{ LINUX_CAN_ERR, "ERR" },
{ 0, NULL }
};
static void can_prompt(packet_info *pinfo _U_, gchar* result)
{
g_snprintf(result, MAX_DECODE_AS_PROMPT_LEN, "Next level protocol as");
}
static gpointer can_value(packet_info *pinfo _U_)
{
return 0;
}
static int
dissect_socketcan_common(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree,
guint encoding)
{
proto_tree *can_tree;
proto_item *ti;
guint8 frame_type;
gint frame_len;
struct can_identifier can_id;
guint32 raw_can_id;
tvbuff_t* next_tvb;
int * can_flags[] = {
&hf_can_ident_ext,
&hf_can_extflag,
&hf_can_rtrflag,
&hf_can_errflag,
NULL,
};
raw_can_id = tvb_get_guint32(tvb, 0, encoding);
frame_len = tvb_get_guint8( tvb, CAN_LEN_OFFSET);
if (raw_can_id & CAN_EFF_FLAG)
{
frame_type = LINUX_CAN_EXT;
can_id.id = raw_can_id & CAN_EFF_MASK;
}
else
{
frame_type = LINUX_CAN_STD;
can_id.id = raw_can_id & CAN_SFF_MASK;
can_flags[0] = &hf_can_ident_std;
}
col_set_str(pinfo->cinfo, COL_PROTOCOL, "CAN");
col_clear(pinfo->cinfo, COL_INFO);
/* Error Message Frames are only encapsulated in Classic CAN frames */
if (raw_can_id & CAN_ERR_FLAG)
{
frame_type = LINUX_CAN_ERR;
}
col_add_fstr(pinfo->cinfo, COL_INFO, "%s: 0x%08x ",
val_to_str(frame_type, frame_type_vals, "Unknown (0x%02x)"), can_id.id);
if (raw_can_id & CAN_RTR_FLAG)
{
col_append_str(pinfo->cinfo, COL_INFO, "(Remote Transmission Request)");
}
else
{
col_append_str(pinfo->cinfo, COL_INFO, tvb_bytes_to_str_punct(wmem_packet_scope(), 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_bitmask_list(can_tree, tvb, 0, 4, (const int**)can_flags, encoding);
proto_tree_add_item(can_tree, hf_can_len, tvb, CAN_LEN_OFFSET, 1, ENC_NA);
proto_tree_add_item(can_tree, hf_can_reserved, tvb, CAN_LEN_OFFSET+1, 3, ENC_NA);
next_tvb = tvb_new_subset_length(tvb, CAN_DATA_OFFSET, frame_len);
/* Functionality for choosing subdissector is controlled through Decode As as CAN doesn't
have a unique identifier to determine subdissector */
if (!dissector_try_uint_new(subdissector_table, 0, next_tvb, pinfo, tree, TRUE, &can_id))
{
call_data_dissector(next_tvb, pinfo, tree);
}
if (tvb_captured_length_remaining(tvb, CAN_DATA_OFFSET+frame_len) > 0)
{
proto_tree_add_item(can_tree, hf_can_padding, tvb, CAN_DATA_OFFSET+frame_len, -1, ENC_NA);
}
return tvb_captured_length(tvb);
}
static int
dissect_socketcan_bigendian(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree,
void* data _U_)
{
return dissect_socketcan_common(tvb, pinfo, tree,
byte_swap ? ENC_LITTLE_ENDIAN : ENC_BIG_ENDIAN);
}
#if G_BYTE_ORDER == G_LITTLE_ENDIAN
#define ENC_ANTI_HOST_ENDIAN ENC_BIG_ENDIAN
#else
#define ENC_ANTI_HOST_ENDIAN ENC_LITTLE_ENDIAN
#endif
static int
dissect_socketcan_hostendian(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree,
void* data _U_)
{
return dissect_socketcan_common(tvb, pinfo, tree,
byte_swap ? ENC_ANTI_HOST_ENDIAN : ENC_HOST_ENDIAN);
}
static int
dissect_socketcanfd_common(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree,
guint encoding)
{
proto_tree *can_tree;
proto_item *ti;
guint8 frame_type;
gint frame_len;
struct can_identifier can_id;
guint32 raw_can_id;
tvbuff_t* next_tvb;
int * can_flags_fd[] = {
&hf_can_ident_ext,
&hf_can_extflag,
NULL,
};
static const int * canfd_flag_fields[] = {
&hf_canfd_brsflag,
&hf_canfd_esiflag,
NULL,
};
raw_can_id = tvb_get_guint32(tvb, 0, encoding);
frame_len = tvb_get_guint8( tvb, CAN_LEN_OFFSET);
if (raw_can_id & CAN_EFF_FLAG)
{
frame_type = LINUX_CAN_EXT;
can_id.id = raw_can_id & CAN_EFF_MASK;
}
else
{
frame_type = LINUX_CAN_STD;
can_id.id = raw_can_id & CAN_SFF_MASK;
can_flags_fd[0] = &hf_can_ident_std;
}
col_set_str(pinfo->cinfo, COL_PROTOCOL, "CANFD");
col_clear(pinfo->cinfo, COL_INFO);
col_add_fstr(pinfo->cinfo, COL_INFO, "%s: 0x%08x %s",
val_to_str(frame_type, frame_type_vals, "Unknown (0x%02x)"), can_id.id,
tvb_bytes_to_str_punct(wmem_packet_scope(), tvb, CAN_DATA_OFFSET, frame_len, ' '));
ti = proto_tree_add_item(tree, proto_canfd, tvb, 0, -1, ENC_NA);
can_tree = proto_item_add_subtree(ti, ett_can_fd);
proto_tree_add_bitmask_list(can_tree, tvb, 0, 4, (const int**)can_flags_fd, encoding);
proto_tree_add_item(can_tree, hf_can_len, tvb, CAN_LEN_OFFSET, 1, ENC_NA);
proto_tree_add_bitmask_list(can_tree, tvb, CANFD_FLAG_OFFSET, 1, canfd_flag_fields, ENC_NA);
proto_tree_add_item(can_tree, hf_can_reserved, tvb, CANFD_FLAG_OFFSET+1, 2, ENC_NA);
next_tvb = tvb_new_subset_length(tvb, CAN_DATA_OFFSET, frame_len);
/* Functionality for choosing subdissector is controlled through Decode As as CAN doesn't
have a unique identifier to determine subdissector */
if (!dissector_try_uint_new(subdissector_table, 0, next_tvb, pinfo, tree, TRUE, &can_id))
{
call_data_dissector(next_tvb, pinfo, tree);
}
if (tvb_captured_length_remaining(tvb, CAN_DATA_OFFSET+frame_len) > 0)
{
proto_tree_add_item(can_tree, hf_can_padding, tvb, CAN_DATA_OFFSET+frame_len, -1, ENC_NA);
}
return tvb_captured_length(tvb);
}
static int
dissect_socketcan_fd(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree,
void* data _U_)
{
return dissect_socketcanfd_common(tvb, pinfo, tree,
byte_swap ? ENC_ANTI_HOST_ENDIAN : ENC_HOST_ENDIAN);
}
void
proto_register_socketcan(void)
{
static hf_register_info hf[] = {
{
&hf_can_ident_ext,
{
"Identifier", "can.id",
FT_UINT32, BASE_HEX,
NULL, CAN_EFF_MASK,
NULL, HFILL
}
},
{
&hf_can_ident_std,
{
"Identifier", "can.id",
FT_UINT32, BASE_HEX,
NULL, CAN_SFF_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 Message 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
}
},
{
&hf_can_reserved,
{
"Reserved", "can.reserved",
FT_BYTES, BASE_NONE,
NULL, 0x0,
NULL, HFILL
}
},
{
&hf_can_padding,
{
"Padding", "can.padding",
FT_BYTES, BASE_NONE,
NULL, 0x0,
NULL, HFILL
}
},
{
&hf_canfd_brsflag,
{
"Bit Rate Setting", "canfd.flags.brs",
FT_BOOLEAN, 8,
NULL, CANFD_BRS,
NULL, HFILL
}
},
{
&hf_canfd_esiflag,
{
"Error State Indicator", "canfd.flags.esi",
FT_BOOLEAN, 8,
NULL, CANFD_ESI,
NULL, HFILL
}
},
};
/* Setup protocol subtree array */
static gint *ett[] =
{
&ett_can,
&ett_can_fd
};
module_t *can_module;
/* Decode As handling */
static build_valid_func can_da_build_value[1] = {can_value};
static decode_as_value_t can_da_values = {can_prompt, 1, can_da_build_value};
static decode_as_t can_da = {"can", "Network", "can.subdissector", 1, 0, &can_da_values, NULL, NULL,
decode_as_default_populate_list, decode_as_default_reset, decode_as_default_change, NULL};
proto_can = proto_register_protocol("Controller Area Network", "CAN", "can");
socketcan_bigendian_handle = register_dissector("can-bigendian", dissect_socketcan_bigendian, proto_can);
socketcan_hostendian_handle = register_dissector("can-hostendian", dissect_socketcan_hostendian, proto_can);
proto_canfd = proto_register_protocol("Controller Area Network FD", "CANFD", "canfd");
socketcan_fd_handle = register_dissector("canfd", dissect_socketcan_fd, proto_canfd);
proto_register_field_array(proto_can, hf, array_length(hf));
proto_register_subtree_array(ett, array_length(ett));
subdissector_table = register_dissector_table("can.subdissector",
"CAN next level dissector", proto_can, FT_UINT32, BASE_HEX);
can_module = prefs_register_protocol(proto_can, NULL);
prefs_register_obsolete_preference(can_module, "protocol");
prefs_register_bool_preference(can_module, "byte_swap",
"Byte-swap the CAN ID/flags field",
"Whether the CAN ID/flags field should be byte-swapped",
&byte_swap);
register_decode_as(&can_da);
}
void
proto_reg_handoff_socketcan(void)
{
dissector_add_uint("wtap_encap", WTAP_ENCAP_SOCKETCAN, socketcan_bigendian_handle);
dissector_add_uint("sll.ltype", LINUX_SLL_P_CAN, socketcan_hostendian_handle);
dissector_add_uint("sll.ltype", LINUX_SLL_P_CANFD, socketcan_fd_handle);
}
/*
* Editor modelines - http://www.wireshark.org/tools/modelines.html
*
* Local variables:
* c-basic-offset: 8
* tab-width: 8
* indent-tabs-mode: t
* End:
*
* vi: set shiftwidth=8 tabstop=8 noexpandtab:
* :indentSize=8:tabSize=8:noTabs=false:
*/
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