/* packet-caneth.c * Routines for Controller Area Network over Ethernet dissection * Copyright 2018, Lazar Sumar * * Wireshark - Network traffic analyzer * By Gerald Combs * Copyright 1998 Gerald Combs * * SPDX-License-Identifier: GPL-2.0-or-later */ /* * The CAN-ETH protocol is used for transmitting the Controller Area Network * (CAN) protocol over UDP. * * The protocol definition can be found at http://www.proconx.com/assets/files/products/caneth/canframe.pdf */ #include #include #include #include #define CAN_FRAME_LEN 15 #define CAN_ID_OFFSET 0 #define CAN_DLC_OFFSET 4 #define CAN_DATA_OFFSET 5 #define CAN_EXT_FLAG_OFFSET 13 #define CAN_RTR_FLAG_OFFSET 14 static const gchar magic[] = "ISO11898"; void proto_reg_handoff_caneth(void); void proto_register_caneth(void); static int proto_caneth = -1; static int hf_caneth_magic = -1; static int hf_caneth_version = -1; static int hf_caneth_frames = -1; static int hf_caneth_options = -1; static int hf_caneth_can_ident_ext = -1; static int hf_caneth_can_ident_std = -1; static int hf_caneth_can_extflag = -1; static int hf_caneth_can_rtrflag = -1; static int hf_caneth_can_len = -1; static int hf_caneth_can_padding = -1; #define CANETH_UDP_PORT 11898 static gint ett_caneth = -1; static gint ett_caneth_frames = -1; static gint ett_caneth_can = -1; static int proto_can = -1; // use CAN protocol for consistent filtering /* A sample #define of the minimum length (in bytes) of the protocol data. * If data is received with fewer than this many bytes it is rejected by * the current dissector. */ #define CANETH_MIN_LENGTH 10 static gboolean test_caneth(packet_info *pinfo _U_, tvbuff_t *tvb, int offset, void *data _U_) { /* Check that we have enough length for the Magic, Version, and Length */ if (tvb_reported_length(tvb) < CANETH_MIN_LENGTH) return FALSE; /* Check that the magic id matches */ if (tvb_strneql(tvb, offset, magic, 8) != 0) return FALSE; /* Check that the version is 1 as that is the only supported version */ if (tvb_get_guint8(tvb, offset+8) != 1) return FALSE; /* Check that the version 1 limit of 16 can frames is respected */ if (tvb_get_guint8(tvb, offset+9) > 16) return FALSE; return TRUE; } static guint get_caneth_len(packet_info *pinfo _U_, tvbuff_t *tvb, int offset, void *data _U_) { return (guint) tvb_get_ntohs(tvb, offset+3); } static int dissect_caneth_can(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data _U_) { proto_tree *can_tree; proto_item *ti; guint32 data_len; guint32 raw_can_id; gint8 ext_flag; gint8 rtr_flag; tvbuff_t* next_tvb; struct can_info can_info; ti = proto_tree_add_item(tree, proto_can, tvb, 0, -1, ENC_NA); can_tree = proto_item_add_subtree(ti, ett_caneth_can); ext_flag = tvb_get_guint8(tvb, CAN_EXT_FLAG_OFFSET); rtr_flag = tvb_get_guint8(tvb, CAN_RTR_FLAG_OFFSET); if (ext_flag) { proto_tree_add_item_ret_uint(can_tree, hf_caneth_can_ident_ext, tvb, CAN_ID_OFFSET, 4, ENC_LITTLE_ENDIAN, &raw_can_id); can_info.id = raw_can_id & CAN_EFF_MASK; } else { proto_tree_add_item_ret_uint(can_tree, hf_caneth_can_ident_std, tvb, CAN_ID_OFFSET, 4, ENC_LITTLE_ENDIAN, &raw_can_id); can_info.id = raw_can_id & CAN_SFF_MASK; } can_info.id |= (ext_flag ? CAN_EFF_FLAG : 0) | (rtr_flag ? CAN_RTR_FLAG : 0); proto_tree_add_item_ret_uint(can_tree, hf_caneth_can_len, tvb, CAN_DLC_OFFSET, 1, ENC_NA, &data_len); proto_tree_add_item(can_tree, hf_caneth_can_extflag, tvb, CAN_EXT_FLAG_OFFSET, 1, ENC_NA); proto_tree_add_item(can_tree, hf_caneth_can_rtrflag, tvb, CAN_RTR_FLAG_OFFSET, 1, ENC_NA); next_tvb = tvb_new_subset_length(tvb, CAN_DATA_OFFSET, data_len); if (!socketcan_call_subdissectors(next_tvb, pinfo, tree, &can_info, FALSE)) { call_data_dissector(next_tvb, pinfo, tree); } if (tvb_captured_length_remaining(tvb, CAN_DATA_OFFSET + data_len) > 0) { proto_tree_add_item(can_tree, hf_caneth_can_padding, tvb, CAN_DATA_OFFSET + data_len, -1, ENC_NA); } return tvb_captured_length(tvb); } static int dissect_caneth(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data) { proto_tree *caneth_tree; proto_item *ti; guint32 frame_count, offset; tvbuff_t* next_tvb; if (!test_caneth(pinfo, tvb, 0, data)) return 0; col_set_str(pinfo->cinfo, COL_PROTOCOL, "CAN-ETH"); col_clear(pinfo->cinfo, COL_INFO); ti = proto_tree_add_item(tree, proto_caneth, tvb, 0, -1, ENC_NA); caneth_tree = proto_item_add_subtree(ti, ett_caneth); proto_tree_add_item(caneth_tree, hf_caneth_magic, tvb, 0, 8, ENC_ASCII); proto_tree_add_item(caneth_tree, hf_caneth_version, tvb, 8, 1, ENC_NA); proto_tree_add_item_ret_uint(caneth_tree, hf_caneth_frames, tvb, 9, 1, ENC_NA, &frame_count); for (offset = 10; frame_count-- > 0; offset += CAN_FRAME_LEN) { next_tvb = tvb_new_subset_length(tvb, offset, CAN_FRAME_LEN); dissect_caneth_can(next_tvb, pinfo, tree, data); } if (tvb_captured_length_remaining(tvb, offset) > 0) { proto_tree_add_item(caneth_tree, hf_caneth_options, tvb, offset, -1, ENC_NA); } return tvb_captured_length(tvb); } static gboolean dissect_caneth_heur_udp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data) { return (udp_dissect_pdus(tvb, pinfo, tree, CANETH_MIN_LENGTH, test_caneth, get_caneth_len, dissect_caneth, data) != 0); } void proto_register_caneth(void) { static hf_register_info hf[] = { { &hf_caneth_magic, { "Magic", "caneth.magic", FT_STRING, BASE_NONE, NULL, 0x0, "The magic identifier used to denote the start of a CAN-ETH packet", HFILL } }, { &hf_caneth_version, { "Version", "caneth.version", FT_UINT8, BASE_DEC, NULL, 0x0, NULL, HFILL } }, { &hf_caneth_frames, { "CAN Frames", "caneth.frames", FT_UINT8, BASE_DEC, NULL, 0x0, "Number of enclosed CAN frames", HFILL } }, { &hf_caneth_options, { "Options (Reserved)", "caneth.options", FT_BYTES, BASE_NONE, NULL, 0x0, "Options field, reserved for future use, should be empty", HFILL } }, { &hf_caneth_can_ident_ext, { "Identifier", "can.id", FT_UINT32, BASE_HEX, NULL, CAN_EFF_MASK, NULL, HFILL } }, { &hf_caneth_can_ident_std, { "Identifier", "can.id", FT_UINT32, BASE_HEX, NULL, CAN_SFF_MASK, NULL, HFILL } }, { &hf_caneth_can_extflag, { "Extended Flag", "can.flags.xtd", FT_BOOLEAN, BASE_NONE, NULL, 0, NULL, HFILL } }, { &hf_caneth_can_rtrflag, { "Remote Transmission Request Flag", "can.flags.rtr", FT_BOOLEAN, BASE_NONE, NULL, 0, NULL, HFILL } }, { &hf_caneth_can_len, { "Frame-Length", "can.len", FT_UINT8, BASE_DEC, NULL, 0x0, NULL, HFILL } }, { &hf_caneth_can_padding, { "Padding", "caneth.can.padding", FT_BYTES, BASE_NONE, NULL, 0x0, NULL, HFILL } }, }; static gint *ett[] = { &ett_caneth, &ett_caneth_frames, &ett_caneth_can, }; proto_caneth = proto_register_protocol("Controller Area Network over Ethernet", "CAN-ETH", "caneth"); proto_register_field_array(proto_caneth, hf, array_length(hf)); proto_register_subtree_array(ett, array_length(ett)); } void proto_reg_handoff_caneth(void) { dissector_handle_t caneth_handle = create_dissector_handle(dissect_caneth, proto_caneth); dissector_add_uint_with_preference("udp.port", CANETH_UDP_PORT, caneth_handle); heur_dissector_add("udp", dissect_caneth_heur_udp, "CAN-ETH over UDP", "caneth_udp", proto_caneth, HEURISTIC_ENABLE); proto_can = proto_get_id_by_filter_name("can"); } /* * Editor modelines - https://www.wireshark.org/tools/modelines.html * * Local variables: * c-basic-offset: 4 * tab-width: 8 * indent-tabs-mode: nil * End: * * vi: set shiftwidth=4 tabstop=8 expandtab: * :indentSize=4:tabSize=8:noTabs=true: */