122 lines
2.8 KiB
C
122 lines
2.8 KiB
C
/*-
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* Public platform independent Near Field Communication (NFC) library
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*
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* Copyright (C) 2009, Roel Verdult
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*
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* This program is free software: you can redistribute it and/or modify it
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* under the terms of the GNU Lesser General Public License as published by the
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* Free Software Foundation, either version 3 of the License, or (at your
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* option) any later version.
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*
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* This program is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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* more details.
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*
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* You should have received a copy of the GNU Lesser General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>
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*/
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/**
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* @file iso14443-subr.c
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* @brief Defines some function extracted for ISO/IEC 14443
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*/
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#ifdef HAVE_CONFIG_H
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# include "config.h"
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#endif // HAVE_CONFIG_H
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#include <stdio.h>
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#include <string.h>
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#include <nfc/nfc.h>
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#include "nfc-internal.h"
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/**
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* @brief CRC
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*
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*/
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void
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iso14443a_crc (uint8_t *pbtData, size_t szLen, uint8_t *pbtCrc)
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{
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uint8_t bt;
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uint32_t wCrc = 0x6363;
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do {
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bt = *pbtData++;
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bt = (bt ^ (uint8_t) (wCrc & 0x00FF));
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bt = (bt ^ (bt << 4));
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wCrc = (wCrc >> 8) ^ ((uint32_t) bt << 8) ^ ((uint32_t) bt << 3) ^ ((uint32_t) bt >> 4);
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} while (--szLen);
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*pbtCrc++ = (uint8_t) (wCrc & 0xFF);
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*pbtCrc = (uint8_t) ((wCrc >> 8) & 0xFF);
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}
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/**
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* @brief Append CRC
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*
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*/
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void
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iso14443a_crc_append (uint8_t *pbtData, size_t szLen)
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{
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iso14443a_crc (pbtData, szLen, pbtData + szLen);
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}
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/**
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* @brief Locate historical bytes
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* @see ISO/IEC 14443-4 (5.2.7 Historical bytes)
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*/
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uint8_t *
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iso14443a_locate_historical_bytes (uint8_t *pbtAts, size_t szAts, size_t *pszTk)
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{
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if (szAts) {
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size_t offset = 1;
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if (pbtAts[0] & 0x10) { // TA
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offset++;
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}
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if (pbtAts[0] & 0x20) { // TB
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offset++;
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}
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if (pbtAts[0] & 0x40) { // TC
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offset++;
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}
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if (szAts > offset) {
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*pszTk = (szAts-offset);
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return (pbtAts+offset);
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}
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}
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*pszTk = 0;
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return NULL;
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}
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/**
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* @brief Add cascade tags (0x88) in UID
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* @see ISO/IEC 14443-3 (6.4.4 UID contents and cascade levels)
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*/
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void
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iso14443_cascade_uid (const uint8_t abtUID[], const size_t szUID, uint8_t *pbtCascadedUID, size_t *pszCascadedUID)
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{
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switch (szUID) {
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case 7:
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pbtCascadedUID[0] = 0x88;
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memcpy (pbtCascadedUID + 1, abtUID, 7);
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*pszCascadedUID = 8;
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break;
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case 10:
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pbtCascadedUID[0] = 0x88;
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memcpy (pbtCascadedUID + 1, abtUID, 3);
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pbtCascadedUID[4] = 0x88;
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memcpy (pbtCascadedUID + 5, abtUID + 3, 7);
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*pszCascadedUID = 12;
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break;
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case 4:
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default:
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memcpy (pbtCascadedUID, abtUID, szUID);
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*pszCascadedUID = szUID;
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break;
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}
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}
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