forked from osmocom/wireshark
267 lines
7.0 KiB
C
267 lines
7.0 KiB
C
/* packet-socketcan.c
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* Routines for disassembly of packets from SocketCAN
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* Felix Obenhuber <felix@obenhuber.de>
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*
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* Added support for the DeviceNet Dissector
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* Hans-Joergen Gunnarsson <hag@hms.se>
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* Copyright 2013
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*
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* Wireshark - Network traffic analyzer
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* By Gerald Combs <gerald@wireshark.org>
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* Copyright 1998 Gerald Combs
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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*/
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#include "config.h"
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#include <epan/packet.h>
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#include <epan/prefs.h>
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#include <epan/decode_as.h>
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#include <wiretap/wtap.h>
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#include "packet-sll.h"
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/* controller area network (CAN) kernel definitions
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* These masks are usually defined within <linux/can.h> but are not
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* available on non-Linux platforms; that's the reason for the
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* redefinitions below
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*
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* special address description flags for the CAN_ID */
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#define CAN_EFF_FLAG 0x80000000U /* EFF/SFF is set in the MSB */
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#define CAN_RTR_FLAG 0x40000000U /* remote transmission request */
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#define CAN_ERR_FLAG 0x20000000U /* error frame */
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#define CAN_EFF_MASK 0x1FFFFFFFU /* extended frame format (EFF) */
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void proto_register_socketcan(void);
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void proto_reg_handoff_socketcan(void);
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static int hf_can_len = -1;
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static int hf_can_ident = -1;
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static int hf_can_extflag = -1;
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static int hf_can_rtrflag = -1;
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static int hf_can_errflag = -1;
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static gint ett_can = -1;
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static int proto_can = -1;
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#define LINUX_CAN_STD 0
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#define LINUX_CAN_EXT 1
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#define LINUX_CAN_RTR 2
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#define LINUX_CAN_ERR 3
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#define CAN_LEN_OFFSET 4
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#define CAN_DATA_OFFSET 8
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/* Structure that gets passed between dissectors. Since it's just a simple 32-bit
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value, no sense in creating a header file for it. Just expect subdissectors
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to provide their own.
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*/
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struct can_identifier
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{
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guint32 id;
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};
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static dissector_table_t subdissector_table;
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static const value_string frame_type_vals[] =
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{
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{ LINUX_CAN_STD, "STD" },
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{ LINUX_CAN_EXT, "XTD" },
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{ LINUX_CAN_RTR, "RTR" },
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{ LINUX_CAN_ERR, "ERR" },
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{ 0, NULL }
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};
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static void can_prompt(packet_info *pinfo _U_, gchar* result)
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{
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g_snprintf(result, MAX_DECODE_AS_PROMPT_LEN, "Next level protocol as");
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}
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static gpointer can_value(packet_info *pinfo _U_)
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{
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return 0;
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}
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static int
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dissect_socketcan(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_)
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{
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proto_tree *can_tree;
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proto_item *ti;
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guint8 frame_type;
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gint frame_len;
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struct can_identifier can_id;
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tvbuff_t* next_tvb;
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col_set_str(pinfo->cinfo, COL_PROTOCOL, "CAN");
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col_clear(pinfo->cinfo,COL_INFO);
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frame_len = tvb_get_guint8( tvb, CAN_LEN_OFFSET);
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can_id.id = tvb_get_ntohl(tvb, 0);
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if (can_id.id & CAN_RTR_FLAG)
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{
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frame_type = LINUX_CAN_RTR;
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}
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else if (can_id.id & CAN_ERR_FLAG)
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{
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frame_type = LINUX_CAN_ERR;
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}
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else if (can_id.id & CAN_EFF_FLAG)
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{
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frame_type = LINUX_CAN_EXT;
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}
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else
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{
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frame_type = LINUX_CAN_STD;
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}
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can_id.id &= CAN_EFF_MASK;
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col_add_fstr(pinfo->cinfo, COL_INFO, "%s: 0x%08x",
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val_to_str(frame_type, frame_type_vals, "Unknown (0x%02x)"), can_id.id);
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col_append_fstr(pinfo->cinfo, COL_INFO, " %s",
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tvb_bytes_to_str_punct(wmem_packet_scope(), tvb, CAN_DATA_OFFSET, frame_len, ' '));
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ti = proto_tree_add_item(tree, proto_can, tvb, 0, -1, ENC_NA);
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can_tree = proto_item_add_subtree(ti, ett_can);
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proto_tree_add_item(can_tree, hf_can_ident, tvb, 0, 4, ENC_BIG_ENDIAN);
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proto_tree_add_item(can_tree, hf_can_extflag, tvb, 0, 4, ENC_BIG_ENDIAN);
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proto_tree_add_item(can_tree, hf_can_rtrflag, tvb, 0, 4, ENC_BIG_ENDIAN);
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proto_tree_add_item(can_tree, hf_can_errflag, tvb, 0, 4, ENC_BIG_ENDIAN);
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proto_tree_add_item(can_tree, hf_can_len, tvb, CAN_LEN_OFFSET, 1, ENC_BIG_ENDIAN);
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next_tvb = tvb_new_subset_length(tvb, CAN_DATA_OFFSET, frame_len);
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/* Functionality for choosing subdissector is controlled through Decode As as CAN doesn't
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have a unique identifier to determine subdissector */
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if (!dissector_try_uint_new(subdissector_table, 0, next_tvb, pinfo, tree, FALSE, &can_id))
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{
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call_data_dissector(next_tvb, pinfo, tree);
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}
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return tvb_captured_length(tvb);
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}
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void
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proto_register_socketcan(void)
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{
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static hf_register_info hf[] = {
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{
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&hf_can_ident,
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{
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"Identifier", "can.id",
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FT_UINT32, BASE_HEX,
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NULL, CAN_EFF_MASK,
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NULL, HFILL
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}
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},
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{
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&hf_can_extflag,
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{
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"Extended Flag", "can.flags.xtd",
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FT_BOOLEAN, 32,
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NULL, CAN_EFF_FLAG,
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NULL, HFILL
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}
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},
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{
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&hf_can_rtrflag,
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{
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"Remote Transmission Request Flag", "can.flags.rtr",
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FT_BOOLEAN, 32,
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NULL, CAN_RTR_FLAG,
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NULL, HFILL
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}
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},
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{
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&hf_can_errflag,
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{
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"Error Flag", "can.flags.err",
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FT_BOOLEAN, 32,
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NULL, CAN_ERR_FLAG,
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NULL, HFILL
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}
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},
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{
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&hf_can_len,
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{
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"Frame-Length", "can.len",
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FT_UINT8, BASE_DEC,
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NULL, 0x0,
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NULL, HFILL
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}
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}
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};
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/* Setup protocol subtree array */
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static gint *ett[] =
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{
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&ett_can
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};
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module_t *can_module;
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/* Decode As handling */
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static build_valid_func can_da_build_value[1] = {can_value};
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static decode_as_value_t can_da_values = {can_prompt, 1, can_da_build_value};
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static decode_as_t can_da = {"can", "Network", "can.subdissector", 1, 0, &can_da_values, NULL, NULL,
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decode_as_default_populate_list, decode_as_default_reset, decode_as_default_change, NULL};
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proto_can = proto_register_protocol(
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"Controller Area Network", /* name */
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"CAN", /* short name */
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"can" /* abbrev */
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);
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register_dissector("can", dissect_socketcan, proto_can);
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proto_register_field_array(proto_can, hf, array_length(hf));
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proto_register_subtree_array(ett, array_length(ett));
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subdissector_table = register_dissector_table("can.subdissector",
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"CAN next level dissector", proto_can, FT_UINT32, BASE_HEX, DISSECTOR_TABLE_NOT_ALLOW_DUPLICATE);
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can_module = prefs_register_protocol(proto_can, NULL);
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prefs_register_obsolete_preference(can_module, "protocol");
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register_decode_as(&can_da);
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}
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void
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proto_reg_handoff_socketcan(void)
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{
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dissector_handle_t can_handle;
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can_handle = create_dissector_handle(dissect_socketcan, proto_can);
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dissector_add_uint("wtap_encap", WTAP_ENCAP_SOCKETCAN, can_handle);
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dissector_add_uint("sll.ltype", LINUX_SLL_P_CAN, can_handle);
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}
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/*
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* Editor modelines - http://www.wireshark.org/tools/modelines.html
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*
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* Local variables:
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* c-basic-offset: 8
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* tab-width: 8
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* indent-tabs-mode: t
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* End:
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*
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* vi: set shiftwidth=8 tabstop=8 noexpandtab:
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* :indentSize=8:tabSize=8:noTabs=false:
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*/
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