/* packet-socketcan.c * Routines for disassembly of packets from SocketCAN * Felix Obenhuber * * Added support for the DeviceNet Dissector * Hans-Joergen Gunnarsson * Copyright 2013 * * Wireshark - Network traffic analyzer * By Gerald Combs * 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 #include #include #include #include "packet-sll.h" /* controller area network (CAN) kernel definitions * These masks are usually defined within 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) */ void proto_register_socketcan(void); void proto_reg_handoff_socketcan(void); 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; #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 /* 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 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 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(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void* data _U_) { proto_tree *can_tree; proto_item *ti; guint8 frame_type; gint frame_len; struct can_identifier can_id; tvbuff_t* next_tvb; col_set_str(pinfo->cinfo, COL_PROTOCOL, "CAN"); col_clear(pinfo->cinfo,COL_INFO); frame_len = tvb_get_guint8( tvb, CAN_LEN_OFFSET); can_id.id = tvb_get_ntohl(tvb, 0); if (can_id.id & CAN_RTR_FLAG) { frame_type = LINUX_CAN_RTR; } else if (can_id.id & CAN_ERR_FLAG) { frame_type = LINUX_CAN_ERR; } else if (can_id.id & CAN_EFF_FLAG) { frame_type = LINUX_CAN_EXT; } else { frame_type = LINUX_CAN_STD; } can_id.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)"), can_id.id); col_append_fstr(pinfo->cinfo, COL_INFO, " %s", 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_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); 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, FALSE, &can_id)) { call_dissector(data_handle, next_tvb, pinfo, tree); } return tvb_captured_length(tvb); } 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; /* 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", /* name */ "CAN", /* short name */ "can" /* abbrev */ ); 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", FT_UINT32, BASE_HEX, DISSECTOR_TABLE_NOT_ALLOW_DUPLICATE); can_module = prefs_register_protocol(proto_can, NULL); prefs_register_obsolete_preference(can_module, "protocol"); register_decode_as(&can_da); } 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); data_handle = find_dissector("data"); } /* * 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: */