/* 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 * * SPDX-License-Identifier: GPL-2.0-or-later */ #include "config.h" #include #include #include #include #include "packet-sll.h" #include "packet-socketcan.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 0x80000000 /* EFF/SFF is set in the MSB */ #define CAN_RTR_FLAG 0x40000000 /* remote transmission request */ #define CAN_ERR_FLAG 0x20000000 /* error frame */ 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 */ 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 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); if (!dissector_try_payload_new(subdissector_table, 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); if (!dissector_try_payload_new(subdissector_table, 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; 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)); 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); subdissector_table = register_decode_as_next_proto(proto_can, "Network", "can.subdissector", "CAN next level dissector", NULL); } 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: */