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/* packet-pn532_hci.c
* Routines for NXP PN532 HCI Protocol
*
* http://www.nxp.com/documents/user_manual/141520.pdf
*
* Copyright 2013, Michal Labedzki for Tieto Corporation
*
* Wireshark - Network traffic analyzer
* By Gerald Combs <gerald@wireshark.org>
* Copyright 1998 Gerald Combs
*
* SPDX-License-Identifier: GPL-2.0-or-later
*/
#include "config.h"
#include <epan/packet.h>
#include <epan/prefs.h>
#include <epan/expert.h>
#include "packet-usb.h"
static int proto_pn532_hci = -1;
static int hf_preamble = -1;
static int hf_start_code = -1;
static int hf_length = -1;
static int hf_length_checksum = -1;
static int hf_length_checksum_status = -1;
static int hf_extended_length = -1;
static int hf_packet_code = -1;
static int hf_postable = -1;
static int hf_specific_application_level_error_code = -1;
static int hf_data_checksum = -1;
static int hf_data_checksum_status = -1;
static int hf_ignored = -1;
static gint ett_pn532_hci = -1;
static expert_field ei_invalid_length_checksum = EI_INIT;
static expert_field ei_invalid_data_checksum = EI_INIT;
static dissector_handle_t pn532_handle;
static dissector_handle_t pn532_hci_handle;
static const value_string packet_code_vals[] = {
{ 0x00FF, "ACK Frame" },
{ 0x01FF, "Error Frame" },
{ 0xFF00, "NACK Frame" },
{ 0xFFFF, "Extended Information Frame" },
{ 0, NULL }
};
void proto_register_pn532_hci(void);
void proto_reg_handoff_pn532_hci(void);
static gint
dissect_pn532_hci(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree, void *data)
{
proto_item *main_item;
proto_tree *main_tree;
gint offset = 0;
tvbuff_t *next_tvb;
guint16 packet_code;
guint16 length;
guint8 checksum;
usb_conv_info_t *usb_conv_info;
/* Reject the packet if data is NULL */
if (data == NULL)
return 0;
usb_conv_info = (usb_conv_info_t *)data;
length = tvb_captured_length_remaining(tvb, offset);
if (length < 6) return offset;
col_set_str(pinfo->cinfo, COL_PROTOCOL, "PN532_HCI");
col_clear(pinfo->cinfo, COL_INFO);
main_item = proto_tree_add_item(tree, proto_pn532_hci, tvb, offset, -1, ENC_NA);
main_tree = proto_item_add_subtree(main_item, ett_pn532_hci);
length = 0;
while (tvb_captured_length_remaining(tvb, length) >= 2 && tvb_get_ntohs(tvb, length) != 0x00FF) {
length += 1;
}
if (length) {
proto_tree_add_item(main_tree, hf_preamble, tvb, offset, length, ENC_NA);
offset += length;
}
proto_tree_add_item(main_tree, hf_start_code, tvb, offset, 2, ENC_BIG_ENDIAN);
offset += 2;
packet_code = tvb_get_ntohs(tvb, offset);
if (packet_code == 0x00FF) { /* ACK Frame */
col_set_str(pinfo->cinfo, COL_INFO, val_to_str_const(packet_code, packet_code_vals, "Unknown frame"));
proto_tree_add_item(main_tree, hf_packet_code, tvb, offset, 2, ENC_BIG_ENDIAN);
offset += 2;
} else if (packet_code == 0xFF00) { /* NACK Frame */
col_set_str(pinfo->cinfo, COL_INFO, val_to_str_const(packet_code, packet_code_vals, "Unknown frame"));
proto_tree_add_item(main_tree, hf_packet_code, tvb, offset, 2, ENC_BIG_ENDIAN);
offset += 2;
} else if (packet_code == 0x01FF) { /* Error Frame */
col_set_str(pinfo->cinfo, COL_INFO, val_to_str_const(packet_code, packet_code_vals, "Unknown frame"));
proto_tree_add_item(main_tree, hf_packet_code, tvb, offset, 2, ENC_BIG_ENDIAN);
offset += 2;
proto_tree_add_item(main_tree, hf_specific_application_level_error_code, tvb, offset, 1, ENC_BIG_ENDIAN);
offset += 1;
} else if (packet_code == 0xFFFF) { /* Extended Information Frame */
col_set_str(pinfo->cinfo, COL_INFO, "Extended Information Frame");
proto_tree_add_item(main_tree, hf_extended_length, tvb, offset, 2, ENC_BIG_ENDIAN);
length = tvb_get_ntohs(tvb, offset);
offset += 2;
checksum = (length >> 8) + (length & 0xFF) + tvb_get_guint8(tvb, offset);
proto_tree_add_checksum(main_tree, tvb, offset, hf_length_checksum, hf_length_checksum_status, &ei_invalid_length_checksum,
pinfo, checksum, ENC_BIG_ENDIAN, PROTO_CHECKSUM_VERIFY|PROTO_CHECKSUM_ZERO);
offset += 1;
next_tvb = tvb_new_subset_length(tvb, offset, length);
call_dissector_with_data(pn532_handle, next_tvb, pinfo, tree, usb_conv_info);
offset += length;
checksum = tvb_get_guint8(tvb, offset);
while (length) {
checksum += tvb_get_guint8(tvb, offset - length);
length -= 1;
}
proto_tree_add_checksum(main_tree, tvb, offset, hf_data_checksum, hf_data_checksum_status, &ei_invalid_data_checksum, pinfo, 0,
ENC_BIG_ENDIAN, PROTO_CHECKSUM_VERIFY|PROTO_CHECKSUM_ZERO);
offset += 1;
} else { /* Normal Information Frame */
col_set_str(pinfo->cinfo, COL_INFO, "Normal Information Frame");
proto_tree_add_item(main_tree, hf_length, tvb, offset, 1, ENC_BIG_ENDIAN);
length = tvb_get_guint8(tvb, offset);
offset += 1;
checksum = length + tvb_get_guint8(tvb, offset);
proto_tree_add_checksum(main_tree, tvb, offset, hf_length_checksum, hf_length_checksum_status, &ei_invalid_length_checksum,
pinfo, checksum, ENC_BIG_ENDIAN, PROTO_CHECKSUM_VERIFY|PROTO_CHECKSUM_ZERO);
offset += 1;
next_tvb = tvb_new_subset_length(tvb, offset, length);
call_dissector_with_data(pn532_handle, next_tvb, pinfo, tree, usb_conv_info);
offset += length;
proto_tree_add_item(main_tree, hf_data_checksum, tvb, offset, 1, ENC_BIG_ENDIAN);
checksum = tvb_get_guint8(tvb, offset);
while (length) {
checksum += tvb_get_guint8(tvb, offset - length);
length -= 1;
}
if (checksum != 0) {
proto_tree_add_expert(main_tree, pinfo, &ei_invalid_data_checksum, tvb, offset, 1);
}
offset += 1;
}
length = 0;
if (tvb_captured_length_remaining(tvb, offset) == 1) {
length = 1;
} else while (tvb_captured_length_remaining(tvb, offset + length) >= 2 && tvb_get_ntohs(tvb, offset + length) != 0x00FF) {
length += 1;
}
if (length) {
proto_tree_add_item(main_tree, hf_postable, tvb, offset, length, ENC_NA);
offset += length;
}
if (tvb_captured_length_remaining(tvb, offset)) {
proto_tree_add_item(main_tree, hf_ignored, tvb, offset, tvb_captured_length_remaining(tvb, offset), ENC_NA);
offset += tvb_captured_length_remaining(tvb, offset);
}
return offset;
}
void
proto_register_pn532_hci(void)
{
module_t *module;
expert_module_t *expert_module;
static hf_register_info hf[] = {
{ &hf_preamble,
{ "Preamble", "pn532_hci.preamble",
FT_BYTES, BASE_NONE, NULL, 0x00,
NULL, HFILL }
},
{ &hf_start_code,
{ "Start Code", "pn532_hci.start_code",
FT_UINT16, BASE_HEX, NULL, 0x00,
NULL, HFILL }
},
{ &hf_packet_code,
{ "Packet Code", "pn532_hci.packet_code",
FT_UINT16, BASE_HEX, VALS(packet_code_vals), 0x00,
NULL, HFILL }
},
{ &hf_length,
{ "Length", "pn532_hci.length",
FT_UINT8, BASE_DEC, NULL, 0x00,
NULL, HFILL }
},
{ &hf_extended_length,
{ "Extended Length", "pn532_hci.extended_length",
FT_UINT16, BASE_DEC, NULL, 0x00,
NULL, HFILL }
},
{ &hf_length_checksum,
{ "Length Checksum", "pn532_hci.length_checksum",
FT_UINT8, BASE_HEX, NULL, 0x00,
NULL, HFILL }
},
{ &hf_length_checksum_status,
{ "Length Checksum Status", "pn532_hci.length_checksum.status",
FT_UINT8, BASE_NONE, VALS(proto_checksum_vals), 0x00,
NULL, HFILL }
},
{ &hf_data_checksum,
{ "Data Checksum", "pn532_hci.data_checksum",
FT_UINT8, BASE_HEX, NULL, 0x00,
NULL, HFILL }
},
{ &hf_data_checksum_status,
{ "Data Checksum Status", "pn532_hci.data_checksum.status",
FT_UINT8, BASE_NONE, VALS(proto_checksum_vals), 0x00,
NULL, HFILL }
},
{ &hf_specific_application_level_error_code,
{ "Specific Application Level Error Code","pn532_hci.specific_application_level_error_code",
FT_UINT8, BASE_HEX, NULL, 0x00,
NULL, HFILL }
},
{ &hf_postable,
{ "Postamble", "pn532_hci.postamble",
FT_BYTES, BASE_NONE, NULL, 0x00,
NULL, HFILL }
},
{ &hf_ignored,
{ "Ignored", "pn532_hci.ignored",
FT_BYTES, BASE_NONE, NULL, 0x00,
NULL, HFILL }
}
};
static gint *ett[] = {
&ett_pn532_hci
};
static ei_register_info ei[] = {
{ &ei_invalid_length_checksum, { "pn532_hci.expert.invalid_length_checksum", PI_PROTOCOL, PI_WARN, "Invalid Length Checksum", EXPFILL }},
{ &ei_invalid_data_checksum, { "pn532_hci.expert.invalid_data_checksum", PI_PROTOCOL, PI_WARN, "Invalid Data Checksum", EXPFILL }},
};
proto_pn532_hci = proto_register_protocol("NXP PN532 HCI", "PN532_HCI", "pn532_hci");
pn532_hci_handle = register_dissector("pn532_hci", dissect_pn532_hci, proto_pn532_hci);
proto_register_field_array(proto_pn532_hci, hf, array_length(hf));
proto_register_subtree_array(ett, array_length(ett));
expert_module = expert_register_protocol(proto_pn532_hci);
expert_register_field_array(expert_module, ei, array_length(ei));
module = prefs_register_protocol(proto_pn532_hci, NULL);
prefs_register_static_text_preference(module, "version",
"PN532 HCI protocol version is based on: \"UM0701-02; PN532 User Manual\"",
"Version of protocol supported by this dissector.");
}
void
proto_reg_handoff_pn532_hci(void)
{
pn532_handle = find_dissector_add_dependency("pn532", proto_pn532_hci);
dissector_add_uint("usb.product", (0x04e6 << 16) | 0x5591, pn532_hci_handle);
dissector_add_for_decode_as("usb.device", pn532_hci_handle);
dissector_add_for_decode_as("usb.protocol", pn532_hci_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:
*/
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