/* * packet-mdb.c * Routines for MDB dissection * Copyright 2023 Martin Kaiser for PayTec AG (www.paytec.ch) * * Wireshark - Network traffic analyzer * By Gerald Combs * Copyright 1998 Gerald Combs * * SPDX-License-Identifier: GPL-2.0-or-later */ /* * The MDB (Multi-Drop Bus) protocol is used inside a vending machine. MDB * defines the communication between the main control board (VMC = Vending * Machine Controller) and peripheral components, e.g. a payment terminal * or a bill validator. * * The VMC acts as bus master and sends a request to one peripheral at a time. * A peripheral may send data only in response to such a request. * * The MDB specification is maintained by the National Automatic Merchandising * Association (NAMA). As of August 2023, the current version of the MDB * specification is 4.3. It is available from * https://namanow.org/nama-releases-mdb-version-4-3/ * * The pcap input format for this dissector is documented at * https://www.kaiser.cx/pcap-mdb.html */ #include "config.h" #include #include #include void proto_register_mdb(void); static dissector_handle_t mdb_handle; static int proto_mdb = -1; static int ett_mdb = -1; static int ett_mdb_hdr = -1; static int ett_mdb_cl = -1; static int ett_mdb_cgw = -1; static int hf_mdb_hdr_ver = -1; static int hf_mdb_event = -1; static int hf_mdb_addr = -1; static int hf_mdb_cmd = -1; static int hf_mdb_cl_setup_sub = -1; static int hf_mdb_cl_feat_lvl = -1; static int hf_mdb_cl_cols = -1; static int hf_mdb_cl_rows = -1; static int hf_mdb_cl_disp_info = -1; static int hf_mdb_cl_max_price = -1; static int hf_mdb_cl_min_price = -1; static int hf_mdb_cl_vend_sub = -1; static int hf_mdb_cl_item_price = -1; static int hf_mdb_cl_item_num = -1; static int hf_mdb_cl_reader_sub = -1; static int hf_mdb_cl_resp = -1; static int hf_mdb_cl_scale = -1; static int hf_mdb_cl_dec_pl = -1; static int hf_mdb_cl_max_rsp_time = -1; static int hf_mdb_cl_vend_amt = -1; static int hf_mdb_cl_expns_sub = -1; static int hf_mdb_cl_manuf_code = -1; static int hf_mdb_cl_ser_num = -1; static int hf_mdb_cl_mod_num = -1; static int hf_mdb_cl_opt_feat = -1; static int hf_mdb_cgw_feat_lvl = -1; static int hf_mdb_cgw_scale = -1; static int hf_mdb_cgw_dec_pl = -1; static int hf_mdb_cgw_resp = -1; static int hf_mdb_cgw_max_rsp_time = -1; static int hf_mdb_cgw_report_sub = -1; static int hf_mdb_cgw_dts_evt_code = -1; static int hf_mdb_cgw_duration = -1; static int hf_mdb_cgw_activity = -1; static int hf_mdb_cgw_expns_sub = -1; static int hf_mdb_cgw_opt_feat = -1; static int hf_mdb_cgw_manuf_code = -1; static int hf_mdb_cgw_ser_num = -1; static int hf_mdb_cgw_mod_num = -1; static int hf_mdb_ack = -1; static int hf_mdb_data = -1; static int hf_mdb_chk = -1; static expert_field ei_mdb_short_packet = EI_INIT; #define MDB_EVT_DATA_MST_PER 0xFF #define MDB_EVT_DATA_PER_MST 0xFE #define MDB_EVT_BUS_RESET 0xFD static const value_string mdb_event[] = { { MDB_EVT_DATA_MST_PER, "Data transfer Master -> Peripheral" }, { MDB_EVT_DATA_PER_MST, "Data transfer Peripheral -> Master" }, { MDB_EVT_BUS_RESET, "Bus reset" }, { 0, NULL } }; #define ADDR_VMC "VMC" #define ADDR_CASHLESS1 0x10 #define ADDR_COMMS_GW 0x18 static const value_string mdb_addr[] = { { 0x08, "Changer" }, { ADDR_CASHLESS1, "Cashless #1" }, { ADDR_COMMS_GW, "Communications Gateway" }, { 0x30, "Bill Validator" }, { 0x60, "Cashless #2" }, { 0x68, "Age Verification Device" }, { 0, NULL } }; static const value_string mdb_ack[] = { { 0x00, "ACK" }, { 0xAA, "RET" }, { 0xFF, "NAK" }, { 0, NULL } }; /* * These are just the command bits in the address + command byte. MDB supports * two Cashless peripherals (Cashless #1 and #2) with different addresses, * both use the same commands. */ #define MDB_CL_CMD_SETUP 0x01 #define MDB_CL_CMD_VEND 0x03 #define MDB_CL_CMD_READER 0x04 #define MDB_CL_CMD_EXPNS 0x07 static const value_string mdb_cl_cmd[] = { { 0x00, "Reset" }, { MDB_CL_CMD_SETUP, "Setup" }, { 0x02, "Poll" }, { MDB_CL_CMD_VEND, "Vend" }, { MDB_CL_CMD_READER, "Reader" }, { MDB_CL_CMD_EXPNS, "Expansion" }, { 0, NULL } }; #define MDB_CL_SETUP_CFG_DATA 0x00 #define MDB_CL_SETUP_MAX_MIN 0x01 static const value_string mdb_cl_setup_sub_cmd[] = { { MDB_CL_SETUP_CFG_DATA, "Config Data" }, { MDB_CL_SETUP_MAX_MIN, "Max/Min Prices" }, { 0, NULL } }; #define MDB_CL_VEND_REQ 0x00 #define MDB_CL_VEND_SUC 0x02 static const value_string mdb_cl_vend_sub_cmd[] = { { MDB_CL_VEND_REQ, "Vend Request" }, { MDB_CL_VEND_SUC, "Vend Success" }, { 0x04, "Session Complete" }, { 0, NULL } }; static const value_string mdb_cl_reader_sub_cmd[] = { { 0x00, "Reader Disable" }, { 0x01, "Reader Enable" }, { 0, NULL } }; #define MDB_CL_EXPNS_REQ_ID 0x00 #define MDB_CL_EXPNS_OPT_ENA 0x04 static const value_string mdb_cl_expns_sub_cmd[] = { { MDB_CL_EXPNS_REQ_ID, "Request ID" }, { MDB_CL_EXPNS_OPT_ENA, "Optional Feature Enabled" }, { 0, NULL } }; #define MDB_CL_RESP_RD_CFG_DATA 0x01 #define MDB_CL_RESP_VEND_APRV 0x05 #define MDB_CL_RESP_PER_ID 0x09 static const value_string mdb_cl_resp[] = { { 0x00, "Just Reset" }, { MDB_CL_RESP_RD_CFG_DATA, "Reader Config Data" }, { 0x03, "Begin Session" }, { MDB_CL_RESP_VEND_APRV, "Vend Approved" }, { 0x06, "Vend Denied" }, { 0x07, "End Session" }, { MDB_CL_RESP_PER_ID, "Peripheral ID" }, { 0x0b, "Cmd Out Of Sequence" }, { 0, NULL } }; /* * For the Communications Gateway, we use the complete address + command byte * as value for the value string. The values here match those in the MDB * specification. * * There's only one Communications Gateway, the address bits are always the * same. (This is different from the Cashless peripherals, see above.) */ #define MDB_CGW_ADDR_CMD_SETUP 0x19 #define MDB_CGW_ADDR_CMD_REPORT 0x1B #define MDB_CGW_ADDR_CMD_EXPNS 0x1F static const value_string mdb_cgw_addr_cmd[] = { { 0x18, "Reset" }, { MDB_CGW_ADDR_CMD_SETUP, "Setup" }, { 0x1A, "Poll" }, { MDB_CGW_ADDR_CMD_REPORT, "Report" }, { MDB_CGW_ADDR_CMD_EXPNS, "Expansion" }, { 0, NULL } }; #define MDB_CGW_REPORT_DTS_EVT 0x02 static const value_string mdb_cgw_report_sub_cmd[] = { { 0x01, "Transaction" }, { MDB_CGW_REPORT_DTS_EVT, "DTS Event" }, { 0, NULL } }; #define MDB_CGW_EXPNS_FEAT_ENA 0x01 static const value_string mdb_cgw_expns_sub_cmd[] = { { 0x00, "Identification" }, { MDB_CGW_EXPNS_FEAT_ENA, "Feature enable" }, { 0x02, "Time/Date Request" }, { 0, NULL } }; #define MDB_CGW_RESP_CFG 0x01 #define MDB_CGW_RESP_PER_ID 0x06 static const value_string mdb_cgw_resp[] = { { 0x00, "Just Reset" }, { MDB_CGW_RESP_CFG, "Comms Gateway Config" }, { 0x05, "DTS Event Acknowledge" }, { MDB_CGW_RESP_PER_ID, "Peripheral ID" }, { 0, NULL } }; static void dissect_mdb_ack(tvbuff_t *tvb, gint offset, packet_info *pinfo, proto_tree *tree) { guint32 ack; proto_tree_add_item_ret_uint(tree, hf_mdb_ack, tvb, offset, 1, ENC_BIG_ENDIAN, &ack); col_set_str(pinfo->cinfo, COL_INFO, val_to_str_const(ack, mdb_ack, "Invalid ack byte")); } static void mdb_set_addrs(guint8 event, guint8 addr, packet_info *pinfo) { const char *periph = val_to_str(addr, mdb_addr, "Unknown (0x%02x)"); /* pinfo->p2p_dir is from the perspective of the master (VMC) */ if (event == MDB_EVT_DATA_MST_PER) { set_address(&pinfo->src, AT_STRINGZ, (int)strlen(ADDR_VMC)+1, ADDR_VMC); set_address(&pinfo->dst, AT_STRINGZ, (int)strlen(periph)+1, periph); pinfo->p2p_dir = P2P_DIR_SENT; } else if (event == MDB_EVT_DATA_PER_MST) { set_address(&pinfo->src, AT_STRINGZ, (int)strlen(periph)+1, periph); set_address(&pinfo->dst, AT_STRINGZ, (int)strlen(ADDR_VMC)+1, ADDR_VMC); pinfo->p2p_dir = P2P_DIR_RECV; } } static void dissect_mdb_cl_setup(tvbuff_t *tvb, gint offset, packet_info *pinfo, proto_tree *tree) { guint32 sub_cmd, price; const gchar *s; proto_item *pi; proto_tree_add_item_ret_uint(tree, hf_mdb_cl_setup_sub, tvb, offset, 1, ENC_BIG_ENDIAN, &sub_cmd); s = try_val_to_str(sub_cmd, mdb_cl_setup_sub_cmd); if (s) { col_set_str(pinfo->cinfo, COL_INFO, s); } offset++; switch (sub_cmd) { case MDB_CL_SETUP_CFG_DATA: proto_tree_add_item(tree, hf_mdb_cl_feat_lvl, tvb, offset, 1, ENC_BIG_ENDIAN); offset++; proto_tree_add_item(tree, hf_mdb_cl_cols, tvb, offset, 1, ENC_BIG_ENDIAN); offset++; proto_tree_add_item(tree, hf_mdb_cl_rows, tvb, offset, 1, ENC_BIG_ENDIAN); offset++; proto_tree_add_item(tree, hf_mdb_cl_disp_info, tvb, offset, 1, ENC_BIG_ENDIAN); break; case MDB_CL_SETUP_MAX_MIN: if (tvb_reported_length_remaining(tvb, offset) == 5) { /* This is the "default version" of Max/Min Prices. */ /* XXX - convert the scaled prices into actual amounts */ price = tvb_get_ntohs(tvb, offset); pi = proto_tree_add_uint_format(tree, hf_mdb_cl_max_price, tvb, offset, 2, price, "Maximum price: 0x%04x", price); if (price == 0xFFFF) { proto_item_append_text(pi, " (unknown)"); } offset += 2; price = tvb_get_ntohs(tvb, offset); pi = proto_tree_add_uint_format(tree, hf_mdb_cl_min_price, tvb, offset, 2, price, "Minimum price: 0x%04x", price); if (price == 0x0000) { proto_item_append_text(pi, " (unknown)"); } } else if (tvb_reported_length_remaining(tvb, offset) == 11) { /* This is the "expanded currency version" of Max/Min Prices. */ proto_tree_add_item(tree, hf_mdb_cl_max_price, tvb, offset, 4, ENC_BIG_ENDIAN); offset += 4; proto_tree_add_item(tree, hf_mdb_cl_min_price, tvb, offset, 4, ENC_BIG_ENDIAN); } /* XXX - expert info for other lengths */ break; } } static void dissect_mdb_cl_vend(tvbuff_t *tvb, gint offset, packet_info *pinfo, proto_tree *tree) { guint32 sub_cmd, price, item; const gchar *s; proto_tree_add_item_ret_uint(tree, hf_mdb_cl_vend_sub, tvb, offset, 1, ENC_BIG_ENDIAN, &sub_cmd); s = try_val_to_str(sub_cmd, mdb_cl_vend_sub_cmd); if (s) { col_set_str(pinfo->cinfo, COL_INFO, s); } offset++; switch (sub_cmd) { case MDB_CL_VEND_REQ: if (tvb_reported_length_remaining(tvb, offset) == 5) { proto_tree_add_item_ret_uint(tree, hf_mdb_cl_item_price, tvb, offset, 2, ENC_BIG_ENDIAN, &price); offset += 2; proto_tree_add_item_ret_uint(tree, hf_mdb_cl_item_num, tvb, offset, 2, ENC_BIG_ENDIAN, &item); col_append_fstr(pinfo->cinfo, COL_INFO, " (item %d, price %d)", item, price); } /* XXX - dissect the longer request in Expanded Currency Mode */ break; case MDB_CL_VEND_SUC: proto_tree_add_item(tree, hf_mdb_cl_item_num, tvb, offset, 2, ENC_BIG_ENDIAN); break; } } static gint dissect_mdb_cl_id_fields(tvbuff_t *tvb, gint offset, proto_tree *tree) { proto_tree_add_item(tree, hf_mdb_cl_manuf_code, tvb, offset, 3, ENC_ASCII); offset += 3; proto_tree_add_item(tree, hf_mdb_cl_ser_num, tvb, offset, 12, ENC_ASCII); offset += 12; proto_tree_add_item(tree, hf_mdb_cl_mod_num, tvb, offset, 12, ENC_ASCII); offset += 12; /* XXX - dissect the Software Version bytes */ offset += 2; return offset; } static void dissect_mdb_cl_expns(tvbuff_t *tvb, gint offset, packet_info *pinfo, proto_tree *tree) { guint32 sub_cmd; const gchar *s; proto_tree_add_item_ret_uint(tree, hf_mdb_cl_expns_sub, tvb, offset, 1, ENC_BIG_ENDIAN, &sub_cmd); s = try_val_to_str(sub_cmd, mdb_cl_expns_sub_cmd); if (s) { col_set_str(pinfo->cinfo, COL_INFO, s); } offset++; switch (sub_cmd) { case MDB_CL_EXPNS_REQ_ID: dissect_mdb_cl_id_fields(tvb, offset, tree); break; case MDB_CL_EXPNS_OPT_ENA: /* XXX - add a bitmask for the Optional Feature Bits */ proto_tree_add_item(tree, hf_mdb_cl_opt_feat, tvb, offset, 4, ENC_BIG_ENDIAN); break; } } static void dissect_mdb_cl_rd_cfg_data(tvbuff_t *tvb, gint offset, packet_info *pinfo _U_, proto_tree *tree) { proto_tree_add_item(tree, hf_mdb_cl_feat_lvl, tvb, offset, 1, ENC_BIG_ENDIAN); offset++; /* XXX - dissect Country/Currency Code */ offset += 2; proto_tree_add_item(tree, hf_mdb_cl_scale, tvb, offset, 1, ENC_BIG_ENDIAN); offset++; proto_tree_add_item(tree, hf_mdb_cl_dec_pl, tvb, offset, 1, ENC_BIG_ENDIAN); offset++; proto_tree_add_item(tree, hf_mdb_cl_max_rsp_time, tvb, offset, 1, ENC_TIME_SECS | ENC_BIG_ENDIAN); } static void dissect_mdb_mst_per_cl( tvbuff_t *tvb, gint offset, gint len _U_, packet_info *pinfo, proto_tree *tree, proto_item *cmd_it, guint8 addr_byte) { guint8 cmd = addr_byte & 0x07; /* the 3-bit command */ proto_tree *cl_tree; guint32 sub_cmd; const gchar *s; s = val_to_str_const(cmd, mdb_cl_cmd, "Unknown"); proto_item_append_text(cmd_it, " (%s)", s); col_set_str(pinfo->cinfo, COL_INFO, s); cl_tree = proto_tree_add_subtree(tree, tvb, offset, len, ett_mdb_cl, NULL, "Cashless"); s = NULL; switch (cmd) { case MDB_CL_CMD_SETUP: dissect_mdb_cl_setup(tvb, offset, pinfo, cl_tree); break; case MDB_CL_CMD_VEND: dissect_mdb_cl_vend(tvb, offset, pinfo, cl_tree); break; case MDB_CL_CMD_READER: proto_tree_add_item_ret_uint(cl_tree, hf_mdb_cl_reader_sub, tvb, offset, 1, ENC_BIG_ENDIAN, &sub_cmd); s = try_val_to_str(sub_cmd, mdb_cl_reader_sub_cmd); break; case MDB_CL_CMD_EXPNS: dissect_mdb_cl_expns(tvb, offset, pinfo, cl_tree); break; } if (s) col_set_str(pinfo->cinfo, COL_INFO, s); } static void dissect_mdb_per_mst_cl( tvbuff_t *tvb, gint offset, gint len _U_, packet_info *pinfo, proto_tree *tree) { proto_tree *cl_tree; guint32 cl_resp; cl_tree = proto_tree_add_subtree(tree, tvb, offset, len, ett_mdb_cl, NULL, "Cashless"); proto_tree_add_item_ret_uint(cl_tree, hf_mdb_cl_resp, tvb, offset, 1, ENC_BIG_ENDIAN, &cl_resp); col_set_str(pinfo->cinfo, COL_INFO, val_to_str_const(cl_resp, mdb_cl_resp, "Unknown")); offset++; switch (cl_resp) { case MDB_CL_RESP_RD_CFG_DATA: dissect_mdb_cl_rd_cfg_data(tvb, offset, pinfo, cl_tree); break; case MDB_CL_RESP_VEND_APRV: if (tvb_reported_length_remaining(tvb, offset) == 3) { proto_tree_add_item(cl_tree, hf_mdb_cl_vend_amt, tvb, offset, 2, ENC_BIG_ENDIAN); } /* XXX - dissect the longer response in Expanded Currency Mode */ break; case MDB_CL_RESP_PER_ID: dissect_mdb_cl_id_fields(tvb, offset, tree); /* XXX - check if we have Optional Feature Bits */ break; } } static void dissect_mdb_cgw_report(tvbuff_t *tvb, gint offset, packet_info *pinfo, proto_tree *tree) { guint32 sub_cmd; const gchar *s; proto_tree_add_item_ret_uint(tree, hf_mdb_cgw_report_sub, tvb, offset, 1, ENC_BIG_ENDIAN, &sub_cmd); s = try_val_to_str(sub_cmd, mdb_cgw_report_sub_cmd); if (s) { col_set_str(pinfo->cinfo, COL_INFO, s); } offset++; switch (sub_cmd) { case MDB_CGW_REPORT_DTS_EVT: proto_tree_add_item(tree, hf_mdb_cgw_dts_evt_code, tvb, offset, 10, ENC_ASCII); offset += 10; /* XXX - dissect Date */ offset += 4; /* XXX - dissect Time */ offset += 2; proto_tree_add_item(tree, hf_mdb_cgw_duration, tvb, offset, 4, ENC_BIG_ENDIAN); offset += 4; proto_tree_add_item(tree, hf_mdb_cgw_activity, tvb, offset, 1, ENC_BIG_ENDIAN); break; } } static void dissect_mdb_cgw_expns(tvbuff_t *tvb, gint offset, packet_info *pinfo, proto_tree *tree) { guint32 sub_cmd; const gchar *s; proto_tree_add_item_ret_uint(tree, hf_mdb_cgw_expns_sub, tvb, offset, 1, ENC_BIG_ENDIAN, &sub_cmd); s = try_val_to_str(sub_cmd, mdb_cgw_expns_sub_cmd); if (s) { col_set_str(pinfo->cinfo, COL_INFO, s); } offset++; switch (sub_cmd) { case MDB_CGW_EXPNS_FEAT_ENA: proto_tree_add_item(tree, hf_mdb_cgw_opt_feat, tvb, offset, 4, ENC_BIG_ENDIAN); break; } } static void dissect_mdb_mst_per_cgw( tvbuff_t *tvb, gint offset, gint len, packet_info *pinfo, proto_tree *tree, proto_item *cmd_it, guint8 addr_cmd_byte) { proto_tree *cgw_tree; const gchar *s; s = val_to_str_const(addr_cmd_byte, mdb_cgw_addr_cmd, "Unknown"); proto_item_append_text(cmd_it, " (%s)", s); col_set_str(pinfo->cinfo, COL_INFO, s); cgw_tree = proto_tree_add_subtree(tree, tvb, offset, len, ett_mdb_cgw, NULL, "Communications Gateway"); switch (addr_cmd_byte) { case MDB_CGW_ADDR_CMD_SETUP: proto_tree_add_item(cgw_tree, hf_mdb_cgw_feat_lvl, tvb, offset, 1, ENC_BIG_ENDIAN); offset++; proto_tree_add_item(cgw_tree, hf_mdb_cgw_scale, tvb, offset, 1, ENC_BIG_ENDIAN); offset++; proto_tree_add_item(cgw_tree, hf_mdb_cgw_dec_pl, tvb, offset, 1, ENC_BIG_ENDIAN); break; case MDB_CGW_ADDR_CMD_REPORT: dissect_mdb_cgw_report(tvb, offset, pinfo, cgw_tree); break; case MDB_CGW_ADDR_CMD_EXPNS: dissect_mdb_cgw_expns(tvb, offset, pinfo, cgw_tree); break; } } static void dissect_mdb_per_mst_cgw( tvbuff_t *tvb, gint offset, gint len, packet_info *pinfo _U_, proto_tree *tree) { proto_tree *cgw_tree; guint32 cgw_resp; cgw_tree = proto_tree_add_subtree(tree, tvb, offset, len, ett_mdb_cgw, NULL, "Communications Gateway"); proto_tree_add_item_ret_uint(cgw_tree, hf_mdb_cgw_resp, tvb, offset, 1, ENC_BIG_ENDIAN, &cgw_resp); col_set_str(pinfo->cinfo, COL_INFO, val_to_str_const(cgw_resp, mdb_cgw_resp, "Unknown")); offset++; switch (cgw_resp) { case MDB_CGW_RESP_CFG: proto_tree_add_item(cgw_tree, hf_mdb_cgw_feat_lvl, tvb, offset, 1, ENC_BIG_ENDIAN); offset++; proto_tree_add_item(cgw_tree, hf_mdb_cgw_max_rsp_time, tvb, offset, 2, ENC_TIME_SECS | ENC_BIG_ENDIAN); break; case MDB_CGW_RESP_PER_ID: proto_tree_add_item(tree, hf_mdb_cgw_manuf_code, tvb, offset, 3, ENC_ASCII); offset += 3; proto_tree_add_item(tree, hf_mdb_cgw_ser_num, tvb, offset, 12, ENC_ASCII); offset += 12; proto_tree_add_item(tree, hf_mdb_cgw_mod_num, tvb, offset, 12, ENC_ASCII); offset += 12; /* XXX - dissect the Software Version bytes */ offset += 2; proto_tree_add_item(tree, hf_mdb_cgw_opt_feat, tvb, offset, 4, ENC_BIG_ENDIAN); break; } } static void dissect_mdb_mst_per(tvbuff_t *tvb, gint offset, packet_info *pinfo, proto_tree *tree) { guint8 addr_byte, addr; gint mst_per_len; guint data_len; proto_item *cmd_it; mst_per_len = tvb_reported_length_remaining(tvb, offset); if (mst_per_len <= 0) { expert_add_info(pinfo, tree, &ei_mdb_short_packet); return; } if (mst_per_len == 1) { dissect_mdb_ack(tvb, offset, pinfo, tree); return; } /* * Our packet has one address byte, an optional data block and one * checksum byte. */ data_len = mst_per_len - 2; /* * The address byte is 5-bit address | 3-bit command. * * The specification uses 8-bit addresses which are the address byte * with the three lowest bits set to 0. * * The commands are defined as the complete address byte (i.e. they * include the address part). This does not make much sense: Cashless #1 * and #2 have different addresses but exactly the same 3-bit commands. * * In this dissector, we try to use the same values as the specification. */ addr_byte = tvb_get_guint8(tvb, offset); addr = addr_byte & 0xF8; proto_tree_add_uint_bits_format_value(tree, hf_mdb_addr, tvb, 8*offset, 5, addr, ENC_BIG_ENDIAN, "0x%02x", addr); cmd_it = proto_tree_add_uint(tree, hf_mdb_cmd, tvb, offset, 1, addr_byte); mdb_set_addrs(MDB_EVT_DATA_MST_PER, addr, pinfo); offset++; /* * We call the peripheral functions even if data_len == 0 so they can fix * up the command with peripheral-specific info. */ switch (addr) { case ADDR_CASHLESS1: dissect_mdb_mst_per_cl(tvb, offset, data_len, pinfo, tree, cmd_it, addr_byte); break; case ADDR_COMMS_GW: dissect_mdb_mst_per_cgw(tvb, offset, data_len, pinfo, tree, cmd_it, addr_byte); break; default: if (data_len > 0) { proto_tree_add_item(tree, hf_mdb_data, tvb, offset, data_len, ENC_NA); } break; } offset += data_len; /* XXX - verify the checksum */ proto_tree_add_item(tree, hf_mdb_chk, tvb, offset, 1, ENC_BIG_ENDIAN); } static void dissect_mdb_per_mst(tvbuff_t *tvb, gint offset, packet_info *pinfo, proto_tree *tree, guint8 addr) { gint per_mst_len; guint data_len; /* * A packet from peripheral to master is either a single ACK/NAK byte or * a non-empty data block followed by one checksum byte. */ per_mst_len = tvb_reported_length_remaining(tvb, offset); if (per_mst_len <= 0) { expert_add_info(pinfo, tree, &ei_mdb_short_packet); return; } if (per_mst_len == 1) { dissect_mdb_ack(tvb, offset, pinfo, tree); return; } data_len = per_mst_len - 1; switch (addr) { case ADDR_CASHLESS1: dissect_mdb_per_mst_cl(tvb, offset, data_len, pinfo, tree); break; case ADDR_COMMS_GW: dissect_mdb_per_mst_cgw(tvb, offset, data_len, pinfo, tree); break; default: proto_tree_add_item(tree, hf_mdb_data, tvb, offset, data_len, ENC_NA); break; } offset += data_len; /* XXX - verify the checksum */ proto_tree_add_item(tree, hf_mdb_chk, tvb, offset, 1, ENC_BIG_ENDIAN); } static int dissect_mdb(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data _U_) { gint offset = 0, offset_ver, offset_evt; guint8 version, event, addr; proto_tree *mdb_tree, *hdr_tree; proto_item *tree_ti, *hdr_ti; /* We need at least the shortest possible pseudo header. */ if (tvb_captured_length(tvb) < 3) return 0; offset_ver = offset; version = tvb_get_guint8(tvb, offset++); if (version != 0) return 0; offset_evt = offset; event = tvb_get_guint8(tvb, offset++); if (!try_val_to_str(event, mdb_event)) return 0; col_set_str(pinfo->cinfo, COL_PROTOCOL, "MDB"); col_clear(pinfo->cinfo, COL_INFO); tree_ti = proto_tree_add_protocol_format(tree, proto_mdb, tvb, 0, tvb_reported_length(tvb), "MDB"); mdb_tree = proto_item_add_subtree(tree_ti, ett_mdb); hdr_tree = proto_tree_add_subtree(mdb_tree, tvb, 0, -1, ett_mdb_hdr, &hdr_ti, "Pseudo header"); proto_tree_add_item(hdr_tree, hf_mdb_hdr_ver, tvb, offset_ver, 1, ENC_BIG_ENDIAN); proto_tree_add_item(hdr_tree, hf_mdb_event, tvb, offset_evt, 1, ENC_BIG_ENDIAN); /* Packets from peripheral to master always have an address byte in their pseudo header. */ if (event == MDB_EVT_DATA_PER_MST) { /* See the comment in dissect_mdb_mst_per about MDB addresses. */ addr = tvb_get_guint8(tvb, offset) & 0xF8; proto_tree_add_uint_bits_format_value(hdr_tree, hf_mdb_addr, tvb, 8*offset, 5, addr, ENC_BIG_ENDIAN, "0x%02x", addr); offset++; mdb_set_addrs(event, addr, pinfo); } /* We're now at the end of the pseudo header. */ proto_item_set_len(hdr_ti, offset); if (event == MDB_EVT_BUS_RESET) return offset; if (event == MDB_EVT_DATA_MST_PER) dissect_mdb_mst_per(tvb, offset, pinfo, mdb_tree); else if (event == MDB_EVT_DATA_PER_MST) dissect_mdb_per_mst(tvb, offset, pinfo, mdb_tree, addr); return tvb_reported_length(tvb); } void proto_register_mdb(void) { expert_module_t* expert_mdb; static gint *ett[] = { &ett_mdb, &ett_mdb_hdr, &ett_mdb_cl, &ett_mdb_cgw }; static hf_register_info hf[] = { { &hf_mdb_hdr_ver, { "Version", "mdb.hdr_ver", FT_UINT8, BASE_HEX, NULL, 0, NULL, HFILL } }, { &hf_mdb_event, { "Event", "mdb.event", FT_UINT8, BASE_HEX, VALS(mdb_event), 0, NULL, HFILL } }, { &hf_mdb_addr, { "Address", "mdb.addr", FT_UINT8, BASE_HEX, NULL, 0, NULL, HFILL } }, { &hf_mdb_cmd, { "Command", "mdb.cmd", FT_UINT8, BASE_HEX, NULL, 0, NULL, HFILL } }, { &hf_mdb_cl_setup_sub, { "Sub-command", "mdb.cashless.setup_sub_cmd", FT_UINT8, BASE_HEX, VALS(mdb_cl_setup_sub_cmd), 0, NULL, HFILL } }, { &hf_mdb_cl_feat_lvl, { "Feature level", "mdb.cashless.feature_level", FT_UINT8, BASE_DEC, NULL, 0, NULL, HFILL } }, { &hf_mdb_cl_cols, { "Columns on display", "mdb.cashless.columns", FT_UINT8, BASE_DEC, NULL, 0, NULL, HFILL } }, { &hf_mdb_cl_rows, { "Rows on display", "mdb.cashless.rows", FT_UINT8, BASE_DEC, NULL, 0, NULL, HFILL } }, { &hf_mdb_cl_disp_info, { "Display information", "mdb.cashless.disp_info", FT_UINT8, BASE_HEX, NULL, 0x07, NULL, HFILL } }, { &hf_mdb_cl_max_price, { "Maximum price", "mdb.cashless.max_price", FT_UINT32, BASE_HEX, NULL, 0, NULL, HFILL } }, { &hf_mdb_cl_min_price, { "Minimum price", "mdb.cashless.min_price", FT_UINT32, BASE_HEX, NULL, 0, NULL, HFILL } }, { &hf_mdb_cl_vend_sub, { "Sub-command", "mdb.cashless.vend_sub_cmd", FT_UINT8, BASE_HEX, VALS(mdb_cl_vend_sub_cmd), 0, NULL, HFILL } }, { &hf_mdb_cl_item_price, { "Item Price", "mdb.cashless.item_price", FT_UINT32, BASE_DEC, NULL, 0, NULL, HFILL } }, { &hf_mdb_cl_item_num, { "Item Number", "mdb.cashless.item_number", FT_UINT32, BASE_DEC, NULL, 0, NULL, HFILL } }, { &hf_mdb_cl_reader_sub, { "Sub-command", "mdb.cashless.reader_sub_cmd", FT_UINT8, BASE_HEX, VALS(mdb_cl_reader_sub_cmd), 0, NULL, HFILL } }, { &hf_mdb_cl_resp, { "Response", "mdb.cashless.resp", FT_UINT8, BASE_HEX, VALS(mdb_cl_resp), 0, NULL, HFILL } }, { &hf_mdb_cl_scale, { "Scale factor", "mdb.cashless.scale_factor", FT_UINT8, BASE_DEC, NULL, 0, NULL, HFILL } }, { &hf_mdb_cl_dec_pl, { "Decimal places", "mdb.cashless.decimal_places", FT_UINT8, BASE_DEC, NULL, 0, NULL, HFILL } }, { &hf_mdb_cl_max_rsp_time, { "Application maximum response time", "mdb.cashless.max_rsp_time", FT_RELATIVE_TIME, BASE_NONE, NULL, 0, NULL, HFILL } }, { &hf_mdb_cl_vend_amt, { "Vend Amount", "mdb.cashless.vend_amount", FT_UINT32, BASE_DEC, NULL, 0, NULL, HFILL } }, { &hf_mdb_cl_expns_sub, { "Sub-command", "mdb.cashless.expansion_sub_cmd", FT_UINT8, BASE_HEX, VALS(mdb_cl_expns_sub_cmd), 0, NULL, HFILL } }, { &hf_mdb_cl_manuf_code, { "Manufacturer Code", "mdb.cashless.manuf_code", FT_STRING, BASE_NONE, NULL, 0, NULL, HFILL } }, { &hf_mdb_cl_ser_num, { "Serial Number", "mdb.cashless.serial_number", FT_STRING, BASE_NONE, NULL, 0, NULL, HFILL } }, { &hf_mdb_cl_mod_num, { "Model Number", "mdb.cashless.model_number", FT_STRING, BASE_NONE, NULL, 0, NULL, HFILL } }, { &hf_mdb_cl_opt_feat, { "Optional Feature Bits", "mdb.cashless.opt_feature_bits", FT_UINT32, BASE_HEX, NULL, 0, NULL, HFILL } }, { &hf_mdb_cgw_feat_lvl, { "Feature level", "mdb.comms_gw.feature_level", FT_UINT8, BASE_DEC, NULL, 0, NULL, HFILL } }, { &hf_mdb_cgw_scale, { "Scale factor", "mdb.comms_gw.scale_factor", FT_UINT8, BASE_DEC, NULL, 0, NULL, HFILL } }, { &hf_mdb_cgw_dec_pl, { "Decimal places", "mdb.comms_gw.decimal_places", FT_UINT8, BASE_DEC, NULL, 0, NULL, HFILL } }, { &hf_mdb_cgw_resp, { "Response", "mdb.comms_gw.resp", FT_UINT8, BASE_HEX, VALS(mdb_cgw_resp), 0, NULL, HFILL } }, { &hf_mdb_cgw_max_rsp_time, { "Application maximum response time", "mdb.comms_gw.max_rsp_time", FT_RELATIVE_TIME, BASE_NONE, NULL, 0, NULL, HFILL } }, { &hf_mdb_cgw_report_sub, { "Sub-command", "mdb.comms_gw.report_sub_cmd", FT_UINT8, BASE_HEX, VALS(mdb_cgw_report_sub_cmd), 0, NULL, HFILL } }, { &hf_mdb_cgw_dts_evt_code, { "DTS Event Code", "mdb.comms_gw.dts_event_code", FT_STRING, BASE_NONE, NULL, 0, NULL, HFILL } }, { &hf_mdb_cgw_duration, { "Duration", "mdb.comms_gw.duration", FT_UINT32, BASE_DEC, NULL, 0, NULL, HFILL } }, { &hf_mdb_cgw_activity, { "Activity", "mdb.comms_gw.activity", FT_BOOLEAN, 8, TFS(&tfs_active_inactive), 0x1, NULL, HFILL } }, { &hf_mdb_cgw_expns_sub, { "Sub-command", "mdb.comms_gw.expansion_sub_cmd", FT_UINT8, BASE_HEX, VALS(mdb_cgw_expns_sub_cmd), 0, NULL, HFILL } }, { &hf_mdb_cgw_opt_feat, { "Optional Feature Bits", "mdb.comms_gw.opt_feature_bits", FT_UINT32, BASE_HEX, NULL, 0, NULL, HFILL } }, { &hf_mdb_cgw_manuf_code, { "Manufacturer Code", "mdb.comms_gw.manuf_code", FT_STRING, BASE_NONE, NULL, 0, NULL, HFILL } }, { &hf_mdb_cgw_ser_num, { "Serial Number", "mdb.comms_gw.serial_number", FT_STRING, BASE_NONE, NULL, 0, NULL, HFILL } }, { &hf_mdb_cgw_mod_num, { "Model Number", "mdb.comms_gw.model_number", FT_STRING, BASE_NONE, NULL, 0, NULL, HFILL } }, { &hf_mdb_ack, { "Ack byte", "mdb.ack", FT_UINT8, BASE_HEX, VALS(mdb_ack), 0, NULL, HFILL } }, { &hf_mdb_data, { "Data", "mdb.data", FT_BYTES, BASE_NONE, NULL, 0, NULL, HFILL } }, { &hf_mdb_chk, { "Checksum", "mdb.chk", FT_UINT8, BASE_HEX, NULL, 0, NULL, HFILL } } }; static ei_register_info ei[] = { { &ei_mdb_short_packet, { "mdb.short_packet", PI_PROTOCOL, PI_ERROR, "MDB packet without payload", EXPFILL }} }; proto_mdb = proto_register_protocol("Multi-Drop Bus", "MDB", "mdb"); proto_register_subtree_array(ett, array_length(ett)); proto_register_field_array(proto_mdb, hf, array_length(hf)); expert_mdb = expert_register_protocol(proto_mdb); expert_register_field_array(expert_mdb, ei, array_length(ei)); mdb_handle = register_dissector("mdb", dissect_mdb, proto_mdb); } void proto_reg_handoff_mdb(void) { dissector_add_uint("wtap_encap", WTAP_ENCAP_MDB, mdb_handle); } /* * 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: */