--- /dev/null
+/* packet-zvt.c
+ * Routines for ZVT dissection
+ * Copyright 2014-2015, Martin Kaiser <martin@kaiser.cx>
+ *
+ * Wireshark - Network traffic analyzer
+ * By Gerald Combs <gerald@wireshark.org>
+ * 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.
+ */
+
+/* ZVT is a manufacturer-independent protocol between payment terminals and
+ * electronic cash-register systems / vending machines
+ *
+ * the specifications are available from http://www.zvt-kassenschnittstelle.de
+ *
+ * ZVT defines a "serial transport protocol" and a "TCP/IP transport
+ * protocol"
+ *
+ * ZVT can sit on top of USB, either the serial or the TCP/IP protocol
+ * can be used in this case - this is not supported for now
+ *
+ * a dump of ZVT data can be converted to pcap, using a user-defined DLT
+ * we register the dissector by name and try to auto-detect the serial
+ * or TCP/IP protocol
+ *
+ * finally, ZVT can run on top of TCP, the default port is 20007, only
+ * the TCP/IP protocol can be used here
+ */
+
+
+#include "config.h"
+
+#include <epan/packet.h>
+#include <epan/prefs.h>
+#include <epan/addr_resolv.h>
+
+/* special characters of the serial transport protocol */
+#define ACK 0x06
+#define NAK 0x15
+#define DLE 0x10 /* data line escape */
+#define STX 0x02 /* start of text */
+
+/* an APDU needs at least a 2-byte control-field and one byte length */
+#define ZVT_APDU_MIN_LEN 3
+
+void proto_register_zvt(void);
+void proto_reg_handoff_zvt(void);
+
+/* the specification mentions tcp port 20007
+ this port is not officially registered with IANA */
+static guint pref_zvt_tcp_port = 0;
+
+static int proto_zvt = -1;
+
+static int ett_zvt = -1;
+static int ett_zvt_apdu = -1;
+
+static int hf_zvt_ctrl = -1;
+static int hf_zvt_len = -1;
+
+static const value_string ctrl_field[] = {
+ { 0x040F, "Status Information" },
+ { 0x04FF, "Intermediate Status Information" },
+ { 0x0600, "Registration" },
+ { 0x0601, "Authorisation" },
+ { 0x060F, "Completion" },
+ { 0x061E, "Abort" },
+ { 0x0650, "End Of Day" },
+ { 0x0670, "Diagnosis" },
+ { 0x0693, "Initialisation" },
+ { 0x06D1, "Print Line" },
+ { 0x06D3, "Print Text Block" },
+ { 0, NULL }
+};
+static value_string_ext ctrl_field_ext = VALUE_STRING_EXT_INIT(ctrl_field);
+
+
+/* dissect a ZVT APDU
+ return -1 if we don't have a complete APDU, 0 if the packet is no ZVT APDU
+ or the length of the ZVT APDU if all goes well */
+static int
+dissect_zvt_apdu(tvbuff_t *tvb, gint offset, packet_info *pinfo _U_, proto_tree *tree)
+{
+ gint offset_start;
+ guint8 len_bytes = 1; /* number of bytes for the len field */
+ guint16 len;
+ proto_item *apdu_it;
+ proto_tree *apdu_tree;
+
+ offset_start = offset;
+
+ if (tvb_captured_length_remaining(tvb, offset) < ZVT_APDU_MIN_LEN)
+ return -1;
+
+ len = tvb_get_guint8(tvb, offset+2);
+ if (len == 0xFF) {
+ len_bytes = 3;
+ len = tvb_get_ntohs(tvb, offset+3);
+ }
+
+ /* ZVT_APDU_MIN_LEN already includes one length byte */
+ if (tvb_captured_length_remaining(tvb, offset) <
+ ZVT_APDU_MIN_LEN + (len_bytes-1) + len) {
+ return -1;
+ }
+
+ apdu_tree = proto_tree_add_subtree(tree,
+ tvb, offset, -1, ett_zvt_apdu, &apdu_it, "ZVT APDU");
+
+ if (tvb_get_guint8(tvb, offset) == 0x80 ||
+ tvb_get_guint8(tvb, offset) == 0x84) {
+ offset += 2;
+ }
+ else {
+ proto_tree_add_item(apdu_tree, hf_zvt_ctrl, tvb, offset, 2, ENC_BIG_ENDIAN);
+ offset += 2;
+ }
+
+ proto_tree_add_uint(apdu_tree, hf_zvt_len, tvb, offset, len_bytes, len);
+ offset += len_bytes;
+
+ offset += len;
+
+ proto_item_set_len(apdu_it, offset - offset_start);
+ return offset - offset_start;
+}
+
+
+static gint
+dissect_zvt_serial(tvbuff_t *tvb, gint offset, packet_info *pinfo _U_, proto_tree *tree)
+{
+ gint offset_start;
+ int apdu_len;
+
+ offset_start = offset;
+
+ if (tvb_reported_length_remaining(tvb, offset) == 1) {
+ offset++; /* ACK or NAK byte */
+ return offset - offset_start;
+ }
+
+ offset ++; /* DLE byte */
+ offset ++; /* STX byte */
+
+ apdu_len = dissect_zvt_apdu(tvb, offset, pinfo, tree);
+ if (apdu_len < 0)
+ return apdu_len;
+
+ offset += apdu_len;
+
+ offset ++; /* DLE byte */
+ offset ++; /* ETX byte */
+ offset += 2; /* CRC bytes */
+
+ return offset - offset_start;
+}
+
+
+static gboolean
+valid_ctrl_field(tvbuff_t *tvb, gint offset)
+{
+ if (tvb_get_guint8(tvb, offset) == 0x80 ||
+ tvb_get_guint8(tvb, offset) == 0x84 ||
+ try_val_to_str_ext(tvb_get_ntohs(tvb, offset), &ctrl_field_ext)) {
+ return TRUE;
+ }
+
+ return FALSE;
+}
+
+
+static int
+dissect_zvt(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data _U_)
+{
+ gint zvt_len = 0;
+ proto_item *zvt_ti;
+ proto_tree *zvt_tree;
+ gboolean is_serial; /* serial or TCP/IP protocol? */
+
+ if (tvb_captured_length(tvb) == 1 &&
+ (tvb_get_guint8(tvb, 0) == ACK ||
+ tvb_get_guint8(tvb, 0) == NAK)) {
+ is_serial = TRUE;
+ }
+ else if (tvb_captured_length(tvb) >= 2 &&
+ tvb_get_guint8(tvb, 0) == DLE &&
+ tvb_get_guint8(tvb, 1) == STX) {
+ is_serial = TRUE;
+ }
+ else if (tvb_captured_length(tvb) >= ZVT_APDU_MIN_LEN &&
+ valid_ctrl_field(tvb, 0)) {
+ is_serial = FALSE;
+ }
+ else
+ return 0;
+
+ col_set_str(pinfo->cinfo, COL_PROTOCOL, "ZVT");
+ col_clear(pinfo->cinfo, COL_INFO);
+ zvt_ti = proto_tree_add_protocol_format(tree, proto_zvt,
+ tvb, 0, -1,
+ "ZVT Kassenschnittstelle: %s", is_serial ?
+ "Serial Transport Protocol" : "Transport Protocol TCP/IP");
+ zvt_tree = proto_item_add_subtree(zvt_ti, ett_zvt);
+
+ if (is_serial)
+ zvt_len = dissect_zvt_serial(tvb, 0, pinfo, zvt_tree);
+ else
+ zvt_len = dissect_zvt_apdu(tvb, 0, pinfo, zvt_tree);
+
+ /* zvt_len < 0 means that we have an incomplete APDU
+ we can't do any reassembly here, so let's consume all bytes */
+ if (zvt_len < 0)
+ zvt_len = tvb_captured_length(tvb);
+
+ proto_item_set_len(zvt_ti, zvt_len);
+ return zvt_len;
+}
+
+
+static int
+dissect_zvt_tcp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data _U_)
+{
+ gint offset = 0, zvt_len = 0, ret;
+ proto_item *zvt_ti;
+ proto_tree *zvt_tree;
+
+ if (tvb_captured_length(tvb) < ZVT_APDU_MIN_LEN) {
+ if (pinfo->can_desegment) {
+ pinfo->desegment_offset = offset;
+ pinfo->desegment_len = DESEGMENT_ONE_MORE_SEGMENT;
+ }
+ return zvt_len;
+ }
+
+ if (!valid_ctrl_field(tvb, 0))
+ return 0; /* reject the packet */
+
+ col_set_str(pinfo->cinfo, COL_PROTOCOL, "ZVT");
+ col_clear(pinfo->cinfo, COL_INFO);
+ zvt_ti = proto_tree_add_protocol_format(tree, proto_zvt,
+ tvb, 0, -1,
+ "ZVT Kassenschnittstelle: Transport Protocol TCP/IP");
+ zvt_tree = proto_item_add_subtree(zvt_ti, ett_zvt);
+
+ while (tvb_captured_length_remaining(tvb, offset) > 0) {
+ ret = dissect_zvt_apdu(tvb, offset, pinfo, zvt_tree);
+ if (ret == 0) {
+ /* not a valid APDU
+ mark the bytes that we consumed and exit, give
+ other dissectors a chance to try the remaining
+ bytes */
+ break;
+ }
+ else if (ret < 0) {
+ /* not enough data - ask the TCP layer for more */
+
+ if (pinfo->can_desegment) {
+ pinfo->desegment_offset = offset;
+ pinfo->desegment_len = DESEGMENT_ONE_MORE_SEGMENT;
+ }
+ break;
+ }
+ else {
+ offset += ret;
+ zvt_len += ret;
+ }
+ }
+
+ proto_item_set_len(zvt_ti, zvt_len);
+ return zvt_len;
+}
+
+
+void
+proto_register_zvt(void)
+{
+ static hf_register_info hf[] = {
+ { &hf_zvt_ctrl,
+ { "Control-field", "zvt.control_field", FT_UINT16,
+ BASE_HEX|BASE_EXT_STRING, &ctrl_field_ext, 0, NULL, HFILL } },
+ { &hf_zvt_len,
+ { "Length-field", "zvt.length_field",
+ FT_UINT16, BASE_DEC, NULL, 0, NULL, HFILL } }
+ };
+ static gint *ett[] = {
+ &ett_zvt,
+ &ett_zvt_apdu
+ };
+
+ module_t *zvt_module;
+
+ proto_zvt = proto_register_protocol(
+ "ZVT Kassenschnittstelle", "ZVT", "zvt");
+ proto_register_field_array(proto_zvt, hf, array_length(hf));
+ proto_register_subtree_array(ett, array_length(ett));
+
+ zvt_module = prefs_register_protocol(proto_zvt, proto_reg_handoff_zvt);
+ prefs_register_uint_preference(zvt_module, "tcp.port",
+ "ZVT TCP Port",
+ "Set the TCP port for ZVT messages (port 20007 according to the spec)",
+ 10,
+ &pref_zvt_tcp_port);
+}
+
+
+void
+proto_reg_handoff_zvt(void)
+{
+ static gboolean registered_dissector = FALSE;
+ static int zvt_tcp_port;
+ static dissector_handle_t zvt_tcp_handle;
+
+ if (!registered_dissector) {
+ /* register by name to allow mapping to a user DLT */
+ new_register_dissector("zvt", dissect_zvt, proto_zvt);
+
+ zvt_tcp_handle = new_create_dissector_handle(dissect_zvt_tcp, proto_zvt);
+
+ registered_dissector = TRUE;
+ }
+ else
+ dissector_delete_uint("tcp.port", zvt_tcp_port, zvt_tcp_handle);
+
+ zvt_tcp_port = pref_zvt_tcp_port;
+ dissector_add_uint("tcp.port", zvt_tcp_port, zvt_tcp_handle);
+}
+
+
+/*
+ * Editor modelines - http://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:
+ */
git.samba.org / metze / wireshark / wip.git / commitdiff