//----------------------------------------------------------------------------- // This code is licensed to you under the terms of the GNU GPL, version 2 or, // at your option, any later version. See the LICENSE.txt file for the text of // the license. //----------------------------------------------------------------------------- // Hitag2 emulation // // (c) 2009 Henryk Plötz //----------------------------------------------------------------------------- // Hitag2 complete rewrite of the code // - Fixed modulation/encoding issues // - Rewrote code for transponder emulation // - Added sniffing of transponder communication // - Added reader functionality // // (c) 2012 Roel Verdult //----------------------------------------------------------------------------- // Piwi, 2019 // Iceman, 2019 #include "hitag2.h" #include "hitag2_crypto.h" #include "hitag.h" #include "proxmark3.h" #include "apps.h" #include "util.h" #include "string.h" #include "BigBuf.h" // Successful crypto auth static bool bCrypto; // Is in auth stage static bool bAuthenticating; // Successful password auth static bool bPwd; static bool bSuccessful; static struct hitag2_tag tag = { .state = TAG_STATE_RESET, .sectors = { // Password mode: | Crypto mode: [0] = { 0x02, 0x4e, 0x02, 0x20}, // UID | UID [1] = { 0x4d, 0x49, 0x4b, 0x52}, // Password RWD | 32 bit LSB key [2] = { 0x20, 0xf0, 0x4f, 0x4e}, // Reserved | 16 bit MSB key, 16 bit reserved [3] = { 0x0e, 0xaa, 0x48, 0x54}, // Configuration, password TAG | Configuration, password TAG [4] = { 0x46, 0x5f, 0x4f, 0x4b}, // Data: F_OK [5] = { 0x55, 0x55, 0x55, 0x55}, // Data: UUUU [6] = { 0xaa, 0xaa, 0xaa, 0xaa}, // Data: .... [7] = { 0x55, 0x55, 0x55, 0x55}, // Data: UUUU [8] = { 0x00, 0x00, 0x00, 0x00}, // RSK Low [9] = { 0x00, 0x00, 0x00, 0x00}, // RSK High [10] = { 0x00, 0x00, 0x00, 0x00}, // RCF [11] = { 0x00, 0x00, 0x00, 0x00}, // SYNC }, }; static enum { WRITE_STATE_START = 0x0, WRITE_STATE_PAGENUM_WRITTEN, WRITE_STATE_PROG } writestate; // ToDo: define a meaningful maximum size for auth_table. The bigger this is, the lower will be the available memory for traces. // Historically it used to be FREE_BUFFER_SIZE, which was 2744. #define AUTH_TABLE_LENGTH 2744 static uint8_t *auth_table; static size_t auth_table_pos = 0; static size_t auth_table_len = AUTH_TABLE_LENGTH; static uint8_t password[4]; static uint8_t NrAr[8]; static uint8_t key[8]; static uint8_t writedata[4]; static uint64_t cipher_state; static int hitag2_reset(void) { tag.state = TAG_STATE_RESET; tag.crypto_active = 0; return 0; } static int hitag2_init(void) { hitag2_reset(); return 0; } // Sam7s has several timers, we will use the source TIMER_CLOCK1 (aka AT91C_TC_CLKS_TIMER_DIV1_CLOCK) // TIMER_CLOCK1 = MCK/2, MCK is running at 48 MHz, Timer is running at 48/2 = 24 MHz // Hitag units (T0) have duration of 8 microseconds (us), which is 1/125000 per second (carrier) // T0 = TIMER_CLOCK1 / 125000 = 192 #ifndef T0 #define T0 192 #endif #define HITAG_FRAME_LEN 20 #define HITAG_T_STOP 36 /* T_EOF should be > 36 */ #define HITAG_T_LOW 8 /* T_LOW should be 4..10 */ #define HITAG_T_0_MIN 15 /* T[0] should be 18..22 */ #define HITAG_T_1_MIN 25 /* T[1] should be 26..30 */ //#define HITAG_T_EOF 40 /* T_EOF should be > 36 */ #define HITAG_T_EOF 80 /* T_EOF should be > 36 */ #define HITAG_T_WAIT_1 200 /* T_wresp should be 199..206 */ #define HITAG_T_WAIT_2 90 /* T_wresp should be 199..206 */ #define HITAG_T_WAIT_MAX 300 /* bit more than HITAG_T_WAIT_1 + HITAG_T_WAIT_2 */ #define HITAG_T_PROG 614 #define HITAG_T_TAG_ONE_HALF_PERIOD 10 #define HITAG_T_TAG_TWO_HALF_PERIOD 25 #define HITAG_T_TAG_THREE_HALF_PERIOD 41 #define HITAG_T_TAG_FOUR_HALF_PERIOD 57 #define HITAG_T_TAG_HALF_PERIOD 16 #define HITAG_T_TAG_FULL_PERIOD 32 #define HITAG_T_TAG_CAPTURE_ONE_HALF 13 #define HITAG_T_TAG_CAPTURE_TWO_HALF 25 #define HITAG_T_TAG_CAPTURE_THREE_HALF 41 #define HITAG_T_TAG_CAPTURE_FOUR_HALF 57 static void hitag_send_bit(int bit) { LED_A_ON(); // Reset clock for the next bit AT91C_BASE_TC0->TC_CCR = AT91C_TC_SWTRG; // Fixed modulation, earlier proxmark version used inverted signal if (bit == 0) { // Manchester: Unloaded, then loaded |__--| LOW(GPIO_SSC_DOUT); while (AT91C_BASE_TC0->TC_CV < T0 * HITAG_T_TAG_HALF_PERIOD); HIGH(GPIO_SSC_DOUT); while (AT91C_BASE_TC0->TC_CV < T0 * HITAG_T_TAG_FULL_PERIOD); } else { // Manchester: Loaded, then unloaded |--__| HIGH(GPIO_SSC_DOUT); while (AT91C_BASE_TC0->TC_CV < T0 * HITAG_T_TAG_HALF_PERIOD); LOW(GPIO_SSC_DOUT); while (AT91C_BASE_TC0->TC_CV < T0 * HITAG_T_TAG_FULL_PERIOD); } LED_A_OFF(); } static void hitag_send_frame(const uint8_t *frame, size_t frame_len) { // SOF - send start of frame hitag_send_bit(1); hitag_send_bit(1); hitag_send_bit(1); hitag_send_bit(1); hitag_send_bit(1); // Send the content of the frame for (size_t i = 0; i < frame_len; i++) { hitag_send_bit((frame[i / 8] >> (7 - (i % 8))) & 1); } // Drop the modulation LOW(GPIO_SSC_DOUT); } // sim static void hitag2_handle_reader_command(uint8_t *rx, const size_t rxlen, uint8_t *tx, size_t *txlen) { uint8_t rx_air[HITAG_FRAME_LEN]; // Copy the (original) received frame how it is send over the air memcpy(rx_air, rx, nbytes(rxlen)); if (tag.crypto_active) { hitag2_cipher_transcrypt(&(tag.cs), rx, rxlen / 8, rxlen % 8); } // Reset the transmission frame length *txlen = 0; // Try to find out which command was send by selecting on length (in bits) switch (rxlen) { // Received 11000 from the reader, request for UID, send UID case 05: { // Always send over the air in the clear plaintext mode if (rx_air[0] != 0xC0) { // Unknown frame ? return; } *txlen = 32; memcpy(tx, tag.sectors[0], 4); tag.crypto_active = 0; } break; // Read/Write command: ..xx x..y yy with yyy == ~xxx, xxx is sector number case 10: { unsigned int sector = (~(((rx[0] << 2) & 0x04) | ((rx[1] >> 6) & 0x03)) & 0x07); // Verify complement of sector index if (sector != ((rx[0] >> 3) & 0x07)) { //DbpString("Transmission error (read/write)"); return; } switch (rx[0] & 0xC6) { // Read command: 11xx x00y case 0xC0: memcpy(tx, tag.sectors[sector], 4); *txlen = 32; break; // Inverted Read command: 01xx x10y case 0x44: for (size_t i = 0; i < 4; i++) { tx[i] = tag.sectors[sector][i] ^ 0xff; } *txlen = 32; break; // Write command: 10xx x01y case 0x82: // Prepare write, acknowledge by repeating command memcpy(tx, rx, nbytes(rxlen)); *txlen = rxlen; tag.active_sector = sector; tag.state = TAG_STATE_WRITING; break; // Unknown command default: Dbprintf("Unknown command: %02x %02x", rx[0], rx[1]); return; break; } } break; // Writing data or Reader password case 32: { if (tag.state == TAG_STATE_WRITING) { // These are the sector contents to be written. We don't have to do anything else. memcpy(tag.sectors[tag.active_sector], rx, nbytes(rxlen)); tag.state = TAG_STATE_RESET; return; } else { // Received RWD password, respond with configuration and our password if (memcmp(rx, tag.sectors[1], 4) != 0) { DbpString("Reader password is wrong"); return; } *txlen = 32; memcpy(tx, tag.sectors[3], 4); } } break; // Received RWD authentication challenge and respnse case 64: { // Store the authentication attempt if (auth_table_len < (AUTH_TABLE_LENGTH - 8)) { memcpy(auth_table + auth_table_len, rx, 8); auth_table_len += 8; } // Reset the cipher state hitag2_cipher_reset(&tag, rx); // Check if the authentication was correct if (!hitag2_cipher_authenticate(&(tag.cs), rx + 4)) { // The reader failed to authenticate, do nothing Dbprintf("auth: %02x%02x%02x%02x%02x%02x%02x%02x Failed!", rx[0], rx[1], rx[2], rx[3], rx[4], rx[5], rx[6], rx[7]); return; } // Succesful, but commented out reporting back to the Host, this may delay to much. // Dbprintf("auth: %02x%02x%02x%02x%02x%02x%02x%02x OK!",rx[0],rx[1],rx[2],rx[3],rx[4],rx[5],rx[6],rx[7]); // Activate encryption algorithm for all further communication tag.crypto_active = 1; // Use the tag password as response memcpy(tx, tag.sectors[3], 4); *txlen = 32; } break; } // LogTrace(rx, nbytes(rxlen), 0, 0, NULL, false); // LogTrace(tx, nbytes(txlen), 0, 0, NULL, true); if (tag.crypto_active) { hitag2_cipher_transcrypt(&(tag.cs), tx, *txlen / 8, *txlen % 8); } } // sim static void hitag_reader_send_bit(int bit) { LED_A_ON(); // Reset clock for the next bit AT91C_BASE_TC0->TC_CCR = AT91C_TC_SWTRG; // Binary puls length modulation (BPLM) is used to encode the data stream // This means that a transmission of a one takes longer than that of a zero // Enable modulation, which means, drop the field HIGH(GPIO_SSC_DOUT); // Wait for 4-10 times the carrier period while (AT91C_BASE_TC0->TC_CV < T0 * 6) {}; // Disable modulation, just activates the field again LOW(GPIO_SSC_DOUT); if (bit == 0) { // Zero bit: |_-| while (AT91C_BASE_TC0->TC_CV < T0 * 22) {}; } else { // One bit: |_--| while (AT91C_BASE_TC0->TC_CV < T0 * 28) {}; } LED_A_OFF(); } // sim static void hitag_reader_send_frame(const uint8_t *frame, size_t frame_len) { // Send the content of the frame for (size_t i = 0; i < frame_len; i++) { hitag_reader_send_bit((frame[i / 8] >> (7 - (i % 8))) & 1); } // Send EOF AT91C_BASE_TC0->TC_CCR = AT91C_TC_SWTRG; // Enable modulation, which means, drop the field HIGH(GPIO_SSC_DOUT); // Wait for 4-10 times the carrier period while (AT91C_BASE_TC0->TC_CV < T0 * 6) {}; // Disable modulation, just activates the field again LOW(GPIO_SSC_DOUT); } size_t blocknr; //----------------------------------------------------------------------------- // Hitag2 operations //----------------------------------------------------------------------------- static bool hitag2_write_page(uint8_t *rx, const size_t rxlen, uint8_t *tx, size_t *txlen) { switch (writestate) { case WRITE_STATE_START: *txlen = 10; tx[0] = 0x82 | (blocknr << 3) | ((blocknr ^ 7) >> 2); tx[1] = ((blocknr ^ 7) << 6); writestate = WRITE_STATE_PAGENUM_WRITTEN; break; case WRITE_STATE_PAGENUM_WRITTEN: // Check if page number was received correctly if ((rxlen == 10) && (rx[0] == (0x82 | (blocknr << 3) | ((blocknr ^ 7) >> 2))) && (rx[1] == (((blocknr & 0x3) ^ 0x3) << 6))) { *txlen = 32; memset(tx, 0, HITAG_FRAME_LEN); memcpy(tx, writedata, 4); writestate = WRITE_STATE_PROG; } else { Dbprintf("hitag2_write_page: Page number was not received correctly: rxlen=%d rx=%02x%02x%02x%02x", rxlen, rx[0], rx[1], rx[2], rx[3]); bSuccessful = false; return false; } break; case WRITE_STATE_PROG: if (rxlen == 0) { bSuccessful = true; } else { bSuccessful = false; Dbprintf("hitag2_write_page: unexpected rx data (%d) after page write", rxlen); } return false; default: DbpString("hitag2_write_page: Unknown state %d"); bSuccessful = false; return false; } return true; } static bool hitag2_password(uint8_t *rx, const size_t rxlen, uint8_t *tx, size_t *txlen, bool write) { // Reset the transmission frame length *txlen = 0; if (bPwd && !bAuthenticating && write) { if (!hitag2_write_page(rx, rxlen, tx, txlen)) { return false; } } else { // Try to find out which command was send by selecting on length (in bits) switch (rxlen) { // No answer, try to resurrect case 0: { // Stop if there is no answer (after sending password) if (bPwd) { DbpString("Password failed!"); return false; } *txlen = 5; memcpy(tx, "\xC0", nbytes(*txlen)); } break; // Received UID, tag password case 32: { // stage 1, got UID if (!bPwd) { bPwd = true; bAuthenticating = true; memcpy(tx, password, 4); *txlen = 32; } else { // stage 2, got config byte+password TAG, discard as will read later if (bAuthenticating) { bAuthenticating = false; if (write) { if (!hitag2_write_page(rx, rxlen, tx, txlen)) { return false; } break; } } // stage 2+, got data block else { memcpy(tag.sectors[blocknr], rx, 4); blocknr++; } if (blocknr > 7) { DbpString("Read succesful!"); bSuccessful = true; return false; } *txlen = 10; tx[0] = 0xC0 | (blocknr << 3) | ((blocknr ^ 7) >> 2); tx[1] = ((blocknr ^ 7) << 6); } } break; // Unexpected response default: { Dbprintf("Uknown frame length: %d", rxlen); return false; } break; } } return true; } static bool hitag2_crypto(uint8_t *rx, const size_t rxlen, uint8_t *tx, size_t *txlen, bool write) { // Reset the transmission frame length *txlen = 0; if (bCrypto) { hitag2_cipher_transcrypt(&cipher_state, rx, rxlen / 8, rxlen % 8); } if (bCrypto && !bAuthenticating && write) { if (!hitag2_write_page(rx, rxlen, tx, txlen)) { return false; } } else { // Try to find out which command was send by selecting on length (in bits) switch (rxlen) { // No answer, try to resurrect case 0: { // Stop if there is no answer while we are in crypto mode (after sending NrAr) if (bCrypto) { // Failed during authentication if (bAuthenticating) { DbpString("Authentication failed!"); return false; } else { // Failed reading a block, could be (read/write) locked, skip block and re-authenticate if (blocknr == 1) { // Write the low part of the key in memory memcpy(tag.sectors[1], key + 2, 4); } else if (blocknr == 2) { // Write the high part of the key in memory tag.sectors[2][0] = 0x00; tag.sectors[2][1] = 0x00; tag.sectors[2][2] = key[0]; tag.sectors[2][3] = key[1]; } else { // Just put zero's in the memory (of the unreadable block) memset(tag.sectors[blocknr], 0x00, 4); } blocknr++; bCrypto = false; } } else { *txlen = 5; memcpy(tx, "\xc0", nbytes(*txlen)); } break; } // Received UID, crypto tag answer case 32: { // stage 1, got UID if (!bCrypto) { uint64_t ui64key = key[0] | ((uint64_t)key[1]) << 8 | ((uint64_t)key[2]) << 16 | ((uint64_t)key[3]) << 24 | ((uint64_t)key[4]) << 32 | ((uint64_t)key[5]) << 40; uint32_t ui32uid = rx[0] | ((uint32_t)rx[1]) << 8 | ((uint32_t)rx[2]) << 16 | ((uint32_t)rx[3]) << 24; Dbprintf("hitag2_crypto: key=0x%x%x uid=0x%x", (uint32_t)((REV64(ui64key)) >> 32), (uint32_t)((REV64(ui64key)) & 0xffffffff), REV32(ui32uid)); cipher_state = _hitag2_init(REV64(ui64key), REV32(ui32uid), 0); // PRN memset(tx, 0x00, 4); // Secret data memset(tx + 4, 0xff, 4); hitag2_cipher_transcrypt(&cipher_state, tx + 4, 4, 0); *txlen = 64; bCrypto = true; bAuthenticating = true; } else { // stage 2, got config byte+password TAG, discard as will read later if (bAuthenticating) { bAuthenticating = false; if (write) { if (!hitag2_write_page(rx, rxlen, tx, txlen)) { return false; } break; } } // stage 2+, got data block else { // Store the received block memcpy(tag.sectors[blocknr], rx, 4); blocknr++; } if (blocknr > 7) { DbpString("Read succesful!"); bSuccessful = true; return false; } else { *txlen = 10; tx[0] = 0xc0 | (blocknr << 3) | ((blocknr ^ 7) >> 2); tx[1] = ((blocknr ^ 7) << 6); } } } break; // Unexpected response default: { Dbprintf("Uknown frame length: %d", rxlen); return false; } break; } } if (bCrypto) { // We have to return now to avoid double encryption if (!bAuthenticating) { hitag2_cipher_transcrypt(&cipher_state, tx, *txlen / 8, *txlen % 8); } } return true; } static bool hitag2_authenticate(uint8_t *rx, const size_t rxlen, uint8_t *tx, size_t *txlen) { // Reset the transmission frame length *txlen = 0; // Try to find out which command was send by selecting on length (in bits) switch (rxlen) { // No answer, try to resurrect case 0: { // Stop if there is no answer while we are in crypto mode (after sending NrAr) if (bCrypto) { DbpString("Authentication failed!"); return false; } *txlen = 5; memcpy(tx, "\xC0", nbytes(*txlen)); } break; // Received UID, crypto tag answer case 32: { if (!bCrypto) { *txlen = 64; memcpy(tx, NrAr, 8); bCrypto = true; } else { DbpString("Authentication succesful!"); return true; } } break; // Unexpected response default: { Dbprintf("Uknown frame length: %d", rxlen); return false; } break; } return true; } static bool hitag2_test_auth_attempts(uint8_t *rx, const size_t rxlen, uint8_t *tx, size_t *txlen) { // Reset the transmission frame length *txlen = 0; // Try to find out which command was send by selecting on length (in bits) switch (rxlen) { // No answer, try to resurrect case 0: { // Stop if there is no answer while we are in crypto mode (after sending NrAr) if (bCrypto) { Dbprintf("auth: %02x%02x%02x%02x%02x%02x%02x%02x Failed, removed entry!", NrAr[0], NrAr[1], NrAr[2], NrAr[3], NrAr[4], NrAr[5], NrAr[6], NrAr[7]); // Removing failed entry from authentiations table memcpy(auth_table + auth_table_pos, auth_table + auth_table_pos + 8, 8); auth_table_len -= 8; // Return if we reached the end of the authentications table bCrypto = false; if (auth_table_pos == auth_table_len) { return false; } // Copy the next authentication attempt in row (at the same position, b/c we removed last failed entry) memcpy(NrAr, auth_table + auth_table_pos, 8); } *txlen = 5; memcpy(tx, "\xc0", nbytes(*txlen)); } break; // Received UID, crypto tag answer, or read block response case 32: { if (!bCrypto) { *txlen = 64; memcpy(tx, NrAr, 8); bCrypto = true; } else { Dbprintf("auth: %02x%02x%02x%02x%02x%02x%02x%02x OK", NrAr[0], NrAr[1], NrAr[2], NrAr[3], NrAr[4], NrAr[5], NrAr[6], NrAr[7]); bCrypto = false; if ((auth_table_pos + 8) == auth_table_len) { return false; } auth_table_pos += 8; memcpy(NrAr, auth_table + auth_table_pos, 8); } } break; default: { Dbprintf("Uknown frame length: %d", rxlen); return false; } break; } return true; } static bool hitag2_read_uid(uint8_t *rx, const size_t rxlen, uint8_t *tx, size_t *txlen) { // Reset the transmission frame length *txlen = 0; // Try to find out which command was send by selecting on length (in bits) switch (rxlen) { // No answer, try to resurrect case 0: { // Just starting or if there is no answer *txlen = 5; memcpy(tx, "\xC0", nbytes(*txlen)); } break; // Received UID case 32: { // Check if we received answer tag (at) if (bAuthenticating) { bAuthenticating = false; } else { // Store the received block memcpy(tag.sectors[blocknr], rx, 4); blocknr++; } if (blocknr > 0) { // DbpString("Read successful!"); bSuccessful = true; return false; } } break; // Unexpected response default: { Dbprintf("Uknown frame length: %d", rxlen); return false; } break; } return true; } // Hitag2 Sniffing void SniffHitag(void) { StopTicks(); // int frame_count; int response; int overflow; bool rising_edge; bool reader_frame; int lastbit; bool bSkip; int tag_sof; uint8_t rx[HITAG_FRAME_LEN]; size_t rxlen = 0; FpgaDownloadAndGo(FPGA_BITSTREAM_LF); BigBuf_free(); BigBuf_Clear_ext(false); clear_trace(); set_tracing(true); auth_table_len = 0; auth_table_pos = 0; auth_table = (uint8_t *)BigBuf_malloc(AUTH_TABLE_LENGTH); memset(auth_table, 0x00, AUTH_TABLE_LENGTH); DbpString("Starting Hitag2 sniffing"); LED_D_ON(); // Set up eavesdropping mode, frequency divisor which will drive the FPGA // and analog mux selection. FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_EDGE_DETECT | FPGA_LF_EDGE_DETECT_TOGGLE_MODE); FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 95); SetAdcMuxFor(GPIO_MUXSEL_LOPKD); // Configure output pin that is connected to the FPGA (for modulating) AT91C_BASE_PIOA->PIO_OER |= GPIO_SSC_DOUT; AT91C_BASE_PIOA->PIO_PER |= GPIO_SSC_DOUT; // Disable modulation, we are going to eavesdrop, not modulate ;) LOW(GPIO_SSC_DOUT); // Enable Peripheral Clock for TIMER_CLOCK1, used to capture edges of the reader frames AT91C_BASE_PMC->PMC_PCER = (1 << AT91C_ID_TC1); AT91C_BASE_PIOA->PIO_BSR = GPIO_SSC_FRAME; // Disable timer during configuration AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKDIS; // TC1: Capture mode, default timer source = MCK/2 (TIMER_CLOCK1), TIOA is external trigger, // external trigger rising edge, load RA on rising edge of TIOA. AT91C_BASE_TC1->TC_CMR = AT91C_TC_CLKS_TIMER_DIV1_CLOCK | AT91C_TC_ETRGEDG_BOTH | AT91C_TC_ABETRG | AT91C_TC_LDRA_BOTH; // Enable and reset counter AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKEN | AT91C_TC_SWTRG; // synchronized startup procedure while (AT91C_BASE_TC1->TC_CV > 0) {}; // wait until TC1 returned to zero // Reset the received frame, frame count and timing info memset(rx, 0x00, sizeof(rx)); // frame_count = 0; response = 0; overflow = 0; reader_frame = false; lastbit = 1; bSkip = true; tag_sof = 4; while (!BUTTON_PRESS() && !data_available()) { // Watchdog hit WDT_HIT(); // Receive frame, watch for at most T0*EOF periods while (AT91C_BASE_TC1->TC_CV < T0 * HITAG_T_EOF) { // Check if rising edge in modulation is detected if (AT91C_BASE_TC1->TC_SR & AT91C_TC_LDRAS) { // Retrieve the new timing values int ra = (AT91C_BASE_TC1->TC_RA / T0); // Find out if we are dealing with a rising or falling edge rising_edge = (AT91C_BASE_PIOA->PIO_PDSR & GPIO_SSC_FRAME) > 0; // Shorter periods will only happen with reader frames if (!reader_frame && rising_edge && ra < HITAG_T_TAG_CAPTURE_ONE_HALF) { // Switch from tag to reader capture LED_C_OFF(); reader_frame = true; memset(rx, 0x00, sizeof(rx)); rxlen = 0; } // Only handle if reader frame and rising edge, or tag frame and falling edge if (reader_frame != rising_edge) { overflow += ra; continue; } // Add the buffered timing values of earlier captured edges which were skipped ra += overflow; overflow = 0; if (reader_frame) { LED_B_ON(); // Capture reader frame if (ra >= HITAG_T_STOP) { if (rxlen != 0) { //DbpString("wierd0?"); } // Capture the T0 periods that have passed since last communication or field drop (reset) response = (ra - HITAG_T_LOW); } else if (ra >= HITAG_T_1_MIN) { // '1' bit rx[rxlen / 8] |= 1 << (7 - (rxlen % 8)); rxlen++; } else if (ra >= HITAG_T_0_MIN) { // '0' bit rx[rxlen / 8] |= 0 << (7 - (rxlen % 8)); rxlen++; } else { // Ignore wierd value, is to small to mean anything } } else { LED_C_ON(); // Capture tag frame (manchester decoding using only falling edges) if (ra >= HITAG_T_EOF) { if (rxlen != 0) { //DbpString("wierd1?"); } // Capture the T0 periods that have passed since last communication or field drop (reset) // We always recieve a 'one' first, which has the falling edge after a half period |-_| response = ra - HITAG_T_TAG_HALF_PERIOD; } else if (ra >= HITAG_T_TAG_CAPTURE_FOUR_HALF) { // Manchester coding example |-_|_-|-_| (101) rx[rxlen / 8] |= 0 << (7 - (rxlen % 8)); rxlen++; rx[rxlen / 8] |= 1 << (7 - (rxlen % 8)); rxlen++; } else if (ra >= HITAG_T_TAG_CAPTURE_THREE_HALF) { // Manchester coding example |_-|...|_-|-_| (0...01) rx[rxlen / 8] |= 0 << (7 - (rxlen % 8)); rxlen++; // We have to skip this half period at start and add the 'one' the second time if (!bSkip) { rx[rxlen / 8] |= 1 << (7 - (rxlen % 8)); rxlen++; } lastbit = !lastbit; bSkip = !bSkip; } else if (ra >= HITAG_T_TAG_CAPTURE_TWO_HALF) { // Manchester coding example |_-|_-| (00) or |-_|-_| (11) if (tag_sof) { // Ignore bits that are transmitted during SOF tag_sof--; } else { // bit is same as last bit rx[rxlen / 8] |= lastbit << (7 - (rxlen % 8)); rxlen++; } } else { // Ignore wierd value, is to small to mean anything } } } } // Check if frame was captured if (rxlen > 0) { // frame_count++; LogTrace(rx, nbytes(rxlen), response, 0, NULL, reader_frame); // Check if we recognize a valid authentication attempt if (nbytes(rxlen) == 8) { // Store the authentication attempt if (auth_table_len < (AUTH_TABLE_LENGTH - 8)) { memcpy(auth_table + auth_table_len, rx, 8); auth_table_len += 8; } } // Reset the received frame and response timing info memset(rx, 0x00, sizeof(rx)); response = 0; reader_frame = false; lastbit = 1; bSkip = true; tag_sof = 4; overflow = 0; LED_B_OFF(); LED_C_OFF(); } else { // Save the timer overflow, will be 0 when frame was received overflow += (AT91C_BASE_TC1->TC_CV / T0); } // Reset the frame length rxlen = 0; // Reset the timer to restart while-loop that receives frames AT91C_BASE_TC1->TC_CCR = AT91C_TC_SWTRG; } LEDsoff(); FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF); set_tracing(false); AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKDIS; // release allocated memory from BigBuff. BigBuf_free(); StartTicks(); DbpString("Hitag2 sniffing end, use `lf hitag list` for annotations"); } // Hitag2 simulation void SimulateHitagTag(bool tag_mem_supplied, uint8_t *data) { StopTicks(); // int frame_count = 0; int response = 0, overflow = 0; uint8_t rx[HITAG_FRAME_LEN]; size_t rxlen = 0; uint8_t tx[HITAG_FRAME_LEN]; size_t txlen = 0; FpgaDownloadAndGo(FPGA_BITSTREAM_LF); BigBuf_free(); BigBuf_Clear_ext(false); clear_trace(); set_tracing(true); auth_table_len = 0; auth_table_pos = 0; auth_table = BigBuf_malloc(AUTH_TABLE_LENGTH); memset(auth_table, 0x00, AUTH_TABLE_LENGTH); // Reset the received frame, frame count and timing info memset(rx, 0x00, sizeof(rx)); DbpString("Starting Hitag2 simulation"); LED_D_ON(); hitag2_init(); if (tag_mem_supplied) { DbpString("Loading hitag2 memory..."); memcpy((uint8_t *)tag.sectors, data, 48); } uint32_t block = 0; for (size_t i = 0; i < 12; i++) { for (size_t j = 0; j < 4; j++) { block <<= 8; block |= tag.sectors[i][j]; } Dbprintf("| %d | %08x |", i, block); } // Set up simulator mode, frequency divisor which will drive the FPGA // and analog mux selection. FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_EDGE_DETECT); FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 95); //125Khz SetAdcMuxFor(GPIO_MUXSEL_LOPKD); // Configure output pin that is connected to the FPGA (for modulating) AT91C_BASE_PIOA->PIO_OER |= GPIO_SSC_DOUT; AT91C_BASE_PIOA->PIO_PER |= GPIO_SSC_DOUT; // Disable modulation at default, which means release resistance LOW(GPIO_SSC_DOUT); // Enable Peripheral Clock for // TIMER_CLOCK0, used to measure exact timing before answering // TIMER_CLOCK1, used to capture edges of the tag frames AT91C_BASE_PMC->PMC_PCER |= (1 << AT91C_ID_TC0) | (1 << AT91C_ID_TC1); AT91C_BASE_PIOA->PIO_BSR = GPIO_SSC_FRAME; // Disable timer during configuration AT91C_BASE_TC0->TC_CCR = AT91C_TC_CLKDIS; AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKDIS; // TC0: Capture mode, default timer source = MCK/2 (TIMER_CLOCK1), no triggers AT91C_BASE_TC0->TC_CMR = AT91C_TC_CLKS_TIMER_DIV1_CLOCK; // TC1: Capture mode, default timer source = MCK/2 (TIMER_CLOCK1), TIOA is external trigger, // external trigger rising edge, load RA on rising edge of TIOA. AT91C_BASE_TC1->TC_CMR = AT91C_TC_CLKS_TIMER_DIV1_CLOCK | AT91C_TC_ETRGEDG_RISING | AT91C_TC_ABETRG | AT91C_TC_LDRA_RISING; // Enable and reset counter AT91C_BASE_TC0->TC_CCR = AT91C_TC_CLKEN | AT91C_TC_SWTRG; AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKEN | AT91C_TC_SWTRG; // synchronized startup procedure while (AT91C_BASE_TC0->TC_CV > 0) {}; // wait until TC0 returned to zero while (!BUTTON_PRESS() && !data_available()) { // Watchdog hit WDT_HIT(); // Receive frame, watch for at most T0*EOF periods while (AT91C_BASE_TC1->TC_CV < T0 * HITAG_T_EOF) { // Check if rising edge in modulation is detected if (AT91C_BASE_TC1->TC_SR & AT91C_TC_LDRAS) { // Retrieve the new timing values int ra = (AT91C_BASE_TC1->TC_RA / T0) + overflow; overflow = 0; // Reset timer every frame, we have to capture the last edge for timing AT91C_BASE_TC0->TC_CCR = AT91C_TC_CLKEN | AT91C_TC_SWTRG; LED_B_ON(); // Capture reader frame if (ra >= HITAG_T_STOP) { if (rxlen != 0) { //DbpString("wierd0?"); } // Capture the T0 periods that have passed since last communication or field drop (reset) response = (ra - HITAG_T_LOW); } else if (ra >= HITAG_T_1_MIN) { // '1' bit rx[rxlen / 8] |= 1 << (7 - (rxlen % 8)); rxlen++; } else if (ra >= HITAG_T_0_MIN) { // '0' bit rx[rxlen / 8] |= 0 << (7 - (rxlen % 8)); rxlen++; } else { // Ignore wierd value, is to small to mean anything } } } // Check if frame was captured if (rxlen > 4) { // frame_count++; LogTrace(rx, nbytes(rxlen), response, response, NULL, true); // Disable timer 1 with external trigger to avoid triggers during our own modulation AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKDIS; // Process the incoming frame (rx) and prepare the outgoing frame (tx) hitag2_handle_reader_command(rx, rxlen, tx, &txlen); // Wait for HITAG_T_WAIT_1 carrier periods after the last reader bit, // not that since the clock counts since the rising edge, but T_Wait1 is // with respect to the falling edge, we need to wait actually (T_Wait1 - T_Low) // periods. The gap time T_Low varies (4..10). All timer values are in // terms of T0 units while (AT91C_BASE_TC0->TC_CV < T0 * (HITAG_T_WAIT_1 - HITAG_T_LOW)); // Send and store the tag answer (if there is any) if (txlen) { hitag_send_frame(tx, txlen); LogTrace(tx, nbytes(txlen), 0, 0, NULL, false); } // Reset the received frame and response timing info memset(rx, 0x00, sizeof(rx)); response = 0; // Enable and reset external trigger in timer for capturing future frames AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKEN | AT91C_TC_SWTRG; LED_B_OFF(); } // Reset the frame length rxlen = 0; // Save the timer overflow, will be 0 when frame was received overflow += (AT91C_BASE_TC1->TC_CV / T0); // Reset the timer to restart while-loop that receives frames AT91C_BASE_TC1->TC_CCR = AT91C_TC_SWTRG; } LEDsoff(); FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF); set_tracing(false); AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKDIS; AT91C_BASE_TC0->TC_CCR = AT91C_TC_CLKDIS; // release allocated memory from BigBuff. BigBuf_free(); StartTicks(); DbpString("Sim Stopped"); } void ReaderHitag(hitag_function htf, hitag_data *htd) { StopTicks(); // int frame_count = 0; int response = 0; uint8_t rx[HITAG_FRAME_LEN]; size_t rxlen = 0; uint8_t txbuf[HITAG_FRAME_LEN]; uint8_t *tx = txbuf; size_t txlen = 0; int lastbit = 1; bool bSkip; int reset_sof; int tag_sof; int t_wait = HITAG_T_WAIT_MAX; bool bStop = false; bSuccessful = false; // Check configuration switch (htf) { case RHT2F_PASSWORD: { Dbprintf("List identifier in password mode"); memcpy(password, htd->pwd.password, 4); blocknr = 0; bPwd = false; bAuthenticating = false; break; } case RHT2F_AUTHENTICATE: { DbpString("Authenticating using nr,ar pair:"); memcpy(NrAr, htd->auth.NrAr, 8); Dbhexdump(8, NrAr, false); bCrypto = false; bAuthenticating = false; break; } case RHT2F_CRYPTO: { DbpString("Authenticating using key:"); memcpy(key, htd->crypto.key, 6); //HACK; 4 or 6?? I read both in the code. Dbhexdump(6, key, false); blocknr = 0; bCrypto = false; bAuthenticating = false; break; } case RHT2F_TEST_AUTH_ATTEMPTS: { Dbprintf("Testing %d authentication attempts", (auth_table_len / 8)); auth_table_pos = 0; memcpy(NrAr, auth_table, 8); bCrypto = false; break; } case RHT2F_UID_ONLY: { blocknr = 0; bCrypto = false; bAuthenticating = false; break; } default: { Dbprintf("Error, unknown function: %d", htf); set_tracing(false); StartTicks(); return; } } FpgaDownloadAndGo(FPGA_BITSTREAM_LF); BigBuf_free(); clear_trace(); set_tracing(true); LED_D_ON(); hitag2_init(); // Set fpga in edge detect with reader field, we can modulate as reader now FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_EDGE_DETECT | FPGA_LF_EDGE_DETECT_READER_FIELD); FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 95); //125Khz SetAdcMuxFor(GPIO_MUXSEL_LOPKD); // Configure output and enable pin that is connected to the FPGA (for modulating) AT91C_BASE_PIOA->PIO_OER |= GPIO_SSC_DOUT; AT91C_BASE_PIOA->PIO_PER |= GPIO_SSC_DOUT; // Disable modulation at default, which means enable the field LOW(GPIO_SSC_DOUT); // Enable Peripheral Clock for // TIMER_CLOCK0, used to measure exact timing before answering // TIMER_CLOCK1, used to capture edges of the tag frames AT91C_BASE_PMC->PMC_PCER |= (1 << AT91C_ID_TC0) | (1 << AT91C_ID_TC1); // PIO_A - BSR AT91C_BASE_PIOA->PIO_BSR = GPIO_SSC_FRAME; // Disable timer during configuration AT91C_BASE_TC0->TC_CCR = AT91C_TC_CLKDIS; AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKDIS; // TC0: Capture mode, default timer source = MCK/2 (TIMER_CLOCK1), no triggers AT91C_BASE_TC0->TC_CMR = AT91C_TC_CLKS_TIMER_DIV1_CLOCK; // TC1: Capture mode, default timer source = MCK/2 (TIMER_CLOCK1), TIOA is external trigger, // external trigger rising edge, load RA on falling edge of TIOA. AT91C_BASE_TC1->TC_CMR = AT91C_TC_CLKS_TIMER_DIV1_CLOCK | AT91C_TC_ETRGEDG_FALLING | AT91C_TC_ABETRG | AT91C_TC_LDRA_FALLING; // Enable and reset counters AT91C_BASE_TC0->TC_CCR = AT91C_TC_CLKEN | AT91C_TC_SWTRG; AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKEN | AT91C_TC_SWTRG; // synchronized startup procedure while (AT91C_BASE_TC0->TC_CV > 0) {}; // wait until TC0 returned to zero // Tag specific configuration settings (sof, timings, etc.) if (htf < 10) { // hitagS settings reset_sof = 1; t_wait = 200; } else if (htf < 20) { // hitag1 settings reset_sof = 1; t_wait = 200; } else if (htf < 30) { // hitag2 settings reset_sof = 4; t_wait = HITAG_T_WAIT_2; } else { Dbprintf("Error, unknown hitag reader type: %d", htf); goto out; } uint8_t attempt_count = 0; while (!bStop && !BUTTON_PRESS() && !data_available()) { WDT_HIT(); // Check if frame was captured and store it if (rxlen > 0) { // frame_count++; LogTrace(rx, nbytes(rxlen), response, response, NULL, false); } // By default reset the transmission buffer tx = txbuf; switch (htf) { case RHT2F_PASSWORD: { bStop = !hitag2_password(rx, rxlen, tx, &txlen, false); break; } case RHT2F_AUTHENTICATE: { bStop = !hitag2_authenticate(rx, rxlen, tx, &txlen); break; } case RHT2F_CRYPTO: { bStop = !hitag2_crypto(rx, rxlen, tx, &txlen, false); break; } case RHT2F_TEST_AUTH_ATTEMPTS: { bStop = !hitag2_test_auth_attempts(rx, rxlen, tx, &txlen); break; } case RHT2F_UID_ONLY: { bStop = !hitag2_read_uid(rx, rxlen, tx, &txlen); attempt_count++; //attempt 3 times to get uid then quit if (!bStop && attempt_count == 3) bStop = true; break; } default: { Dbprintf("Error, unknown function: %d", htf); goto out; } } // Send and store the reader command // Disable timer 1 with external trigger to avoid triggers during our own modulation AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKDIS; // Wait for HITAG_T_WAIT_2 carrier periods after the last tag bit before transmitting, // Since the clock counts since the last falling edge, a 'one' means that the // falling edge occured halfway the period. with respect to this falling edge, // we need to wait (T_Wait2 + half_tag_period) when the last was a 'one'. // All timer values are in terms of T0 units while (AT91C_BASE_TC0->TC_CV < T0 * (t_wait + (HITAG_T_TAG_HALF_PERIOD * lastbit))); // Transmit the reader frame hitag_reader_send_frame(tx, txlen); // Enable and reset external trigger in timer for capturing future frames AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKEN | AT91C_TC_SWTRG; // Add transmitted frame to total count if (txlen > 0) { // frame_count++; LogTrace(tx, nbytes(txlen), HITAG_T_WAIT_2, HITAG_T_WAIT_2, NULL, true); } // Reset values for receiving frames memset(rx, 0x00, sizeof(rx)); rxlen = 0; lastbit = 1; bSkip = true; tag_sof = reset_sof; response = 0; uint32_t errorCount = 0; // Receive frame, watch for at most T0*EOF periods while (AT91C_BASE_TC1->TC_CV < T0 * HITAG_T_WAIT_MAX) { // Check if falling edge in tag modulation is detected if (AT91C_BASE_TC1->TC_SR & AT91C_TC_LDRAS) { // Retrieve the new timing values int ra = (AT91C_BASE_TC1->TC_RA / T0); // Reset timer every frame, we have to capture the last edge for timing AT91C_BASE_TC0->TC_CCR = AT91C_TC_SWTRG; LED_B_ON(); // Capture tag frame (manchester decoding using only falling edges) if (ra >= HITAG_T_EOF) { // Capture the T0 periods that have passed since last communication or field drop (reset) // We always recieve a 'one' first, which has the falling edge after a half period |-_| response = ra - HITAG_T_TAG_HALF_PERIOD; } else if (ra >= HITAG_T_TAG_CAPTURE_FOUR_HALF) { // Manchester coding example |-_|_-|-_| (101) rx[rxlen / 8] |= 0 << (7 - (rxlen % 8)); rxlen++; rx[rxlen / 8] |= 1 << (7 - (rxlen % 8)); rxlen++; } else if (ra >= HITAG_T_TAG_CAPTURE_THREE_HALF) { // Manchester coding example |_-|...|_-|-_| (0...01) rx[rxlen / 8] |= 0 << (7 - (rxlen % 8)); rxlen++; // We have to skip this half period at start and add the 'one' the second time if (!bSkip) { rx[rxlen / 8] |= 1 << (7 - (rxlen % 8)); rxlen++; } lastbit = !lastbit; bSkip = !bSkip; } else if (ra >= HITAG_T_TAG_CAPTURE_TWO_HALF) { // Manchester coding example |_-|_-| (00) or |-_|-_| (11) if (tag_sof) { // Ignore bits that are transmitted during SOF tag_sof--; } else { // bit is same as last bit rx[rxlen / 8] |= lastbit << (7 - (rxlen % 8)); rxlen++; } } else { errorCount++; // Ignore wierd value, is to small to mean anything } } //if we saw over 100 wierd values break it probably isn't hitag... if (errorCount > 100) break; // We can break this loop if we received the last bit from a frame if (AT91C_BASE_TC1->TC_CV > T0 * HITAG_T_EOF) { if (rxlen > 0) break; } } } out: LEDsoff(); FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF); set_tracing(false); AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKDIS; AT91C_BASE_TC0->TC_CCR = AT91C_TC_CLKDIS; // release allocated memory from BigBuff. BigBuf_free(); StartTicks(); if (bSuccessful) reply_old(CMD_ACK, bSuccessful, 0, 0, (uint8_t *)tag.sectors, 48); else reply_old(CMD_ACK, bSuccessful, 0, 0, 0, 0); } void WriterHitag(hitag_function htf, hitag_data *htd, int page) { StopTicks(); // int frame_count = 0; int response = 0; uint8_t rx[HITAG_FRAME_LEN]; size_t rxlen = 0; uint8_t txbuf[HITAG_FRAME_LEN]; uint8_t *tx = txbuf; size_t txlen = 0; int lastbit; int reset_sof; int t_wait = HITAG_T_WAIT_MAX; bool bStop; FpgaDownloadAndGo(FPGA_BITSTREAM_LF); set_tracing(true); clear_trace(); // Reset the return status bSuccessful = false; // Check configuration switch (htf) { case WHT2F_CRYPTO: { DbpString("Authenticating using key:"); memcpy(key, htd->crypto.key, 6); //HACK; 4 or 6?? I read both in the code. memcpy(writedata, htd->crypto.data, 4); Dbhexdump(6, key, false); blocknr = page; bCrypto = false; bAuthenticating = false; writestate = WRITE_STATE_START; } break; case WHT2F_PASSWORD: { DbpString("Authenticating using password:"); memcpy(password, htd->pwd.password, 4); memcpy(writedata, htd->crypto.data, 4); Dbhexdump(4, password, false); blocknr = page; bPwd = false; bAuthenticating = false; writestate = WRITE_STATE_START; } break; default: { Dbprintf("Error, unknown function: %d", htf); StartTicks(); return; } break; } LED_D_ON(); hitag2_init(); // Configure output and enable pin that is connected to the FPGA (for modulating) AT91C_BASE_PIOA->PIO_OER |= GPIO_SSC_DOUT; AT91C_BASE_PIOA->PIO_PER |= GPIO_SSC_DOUT; // Set fpga in edge detect with reader field, we can modulate as reader now FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_EDGE_DETECT | FPGA_LF_EDGE_DETECT_READER_FIELD); FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 95); //125Khz SetAdcMuxFor(GPIO_MUXSEL_LOPKD); // Disable modulation at default, which means enable the field LOW(GPIO_SSC_DOUT); // Enable Peripheral Clock for // TIMER_CLOCK0, used to measure exact timing before answering // TIMER_CLOCK1, used to capture edges of the tag frames AT91C_BASE_PMC->PMC_PCER |= (1 << AT91C_ID_TC0) | (1 << AT91C_ID_TC1); AT91C_BASE_PIOA->PIO_BSR = GPIO_SSC_FRAME; // Disable timer during configuration AT91C_BASE_TC0->TC_CCR = AT91C_TC_CLKDIS; AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKDIS; // TC0: Capture mode, default timer source = MCK/2 (TIMER_CLOCK1), no triggers AT91C_BASE_TC0->TC_CMR = AT91C_TC_CLKS_TIMER_DIV1_CLOCK; // TC1: Capture mode, defaul timer source = MCK/2 (TIMER_CLOCK1), TIOA is external trigger, // external trigger rising edge, load RA on falling edge of TIOA. AT91C_BASE_TC1->TC_CMR = AT91C_TC_CLKS_TIMER_DIV1_CLOCK | AT91C_TC_ETRGEDG_FALLING | AT91C_TC_ABETRG | AT91C_TC_LDRA_FALLING; // Enable and reset counters AT91C_BASE_TC0->TC_CCR = AT91C_TC_CLKEN | AT91C_TC_SWTRG; AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKEN | AT91C_TC_SWTRG; while (AT91C_BASE_TC0->TC_CV > 0) {}; // Reset the received frame, frame count and timing info lastbit = 1; bStop = false; // Tag specific configuration settings (sof, timings, etc.) if (htf < 10) { // hitagS settings reset_sof = 1; t_wait = 200; } else if (htf < 20) { // hitag1 settings reset_sof = 1; t_wait = 200; } else if (htf < 30) { // hitag2 settings reset_sof = 4; t_wait = HITAG_T_WAIT_2; } else { Dbprintf("Error, unknown hitag reader type: %d", htf); return; } while (!bStop && !BUTTON_PRESS() && !data_available()) { WDT_HIT(); // Check if frame was captured and store it if (rxlen > 0) { // frame_count++; LogTrace(rx, nbytes(rxlen), response, response, NULL, false); } // By default reset the transmission buffer tx = txbuf; switch (htf) { case WHT2F_CRYPTO: { bStop = !hitag2_crypto(rx, rxlen, tx, &txlen, true); } break; case WHT2F_PASSWORD: { bStop = !hitag2_password(rx, rxlen, tx, &txlen, true); } break; default: { Dbprintf("Error, unknown function: %d", htf); return; } break; } // Send and store the reader command // Disable timer 1 with external trigger to avoid triggers during our own modulation AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKDIS; // Wait for HITAG_T_WAIT_2 carrier periods after the last tag bit before transmitting, // Since the clock counts since the last falling edge, a 'one' means that the // falling edge occured halfway the period. with respect to this falling edge, // we need to wait (T_Wait2 + half_tag_period) when the last was a 'one'. // All timer values are in terms of T0 units while (AT91C_BASE_TC0->TC_CV < T0 * (t_wait + (HITAG_T_TAG_HALF_PERIOD * lastbit))) {}; // Transmit the reader frame hitag_reader_send_frame(tx, txlen); // Enable and reset external trigger in timer for capturing future frames AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKEN | AT91C_TC_SWTRG; // Add transmitted frame to total count if (txlen > 0) { // frame_count++; LogTrace(tx, nbytes(txlen), HITAG_T_WAIT_2, HITAG_T_WAIT_2, NULL, true); } // Reset values for receiving frames memset(rx, 0x00, sizeof(rx)); rxlen = 0; lastbit = 1; bool bSkip = true; int tag_sof = reset_sof; response = 0; uint32_t errorCount = 0; // Receive frame, watch for at most T0*EOF periods while (AT91C_BASE_TC1->TC_CV < T0 * HITAG_T_WAIT_MAX) { // Check if falling edge in tag modulation is detected if (AT91C_BASE_TC1->TC_SR & AT91C_TC_LDRAS) { // Retrieve the new timing values int ra = (AT91C_BASE_TC1->TC_RA / T0); // Reset timer every frame, we have to capture the last edge for timing AT91C_BASE_TC0->TC_CCR = AT91C_TC_SWTRG; LED_B_ON(); // Capture tag frame (manchester decoding using only falling edges) if (ra >= HITAG_T_EOF) { if (rxlen != 0) { //Dbprintf("DEBUG: Wierd1"); } // Capture the T0 periods that have passed since last communication or field drop (reset) // We always recieve a 'one' first, which has the falling edge after a half period |-_| response = ra - HITAG_T_TAG_HALF_PERIOD; } else if (ra >= HITAG_T_TAG_CAPTURE_FOUR_HALF) { // Manchester coding example |-_|_-|-_| (101) // need to test to verify we don't exceed memory... // if ( ((rxlen+2) / 8) > HITAG_FRAME_LEN) { // break; // } rx[rxlen / 8] |= 0 << (7 - (rxlen % 8)); rxlen++; rx[rxlen / 8] |= 1 << (7 - (rxlen % 8)); rxlen++; } else if (ra >= HITAG_T_TAG_CAPTURE_THREE_HALF) { // Manchester coding example |_-|...|_-|-_| (0...01) // need to test to verify we don't exceed memory... // if ( ((rxlen+2) / 8) > HITAG_FRAME_LEN) { // break; // } rx[rxlen / 8] |= 0 << (7 - (rxlen % 8)); rxlen++; // We have to skip this half period at start and add the 'one' the second time if (!bSkip) { rx[rxlen / 8] |= 1 << (7 - (rxlen % 8)); rxlen++; } lastbit = !lastbit; bSkip = !bSkip; } else if (ra >= HITAG_T_TAG_CAPTURE_TWO_HALF) { // Manchester coding example |_-|_-| (00) or |-_|-_| (11) // need to test to verify we don't exceed memory... // if ( ((rxlen+2) / 8) > HITAG_FRAME_LEN) { // break; // } if (tag_sof) { // Ignore bits that are transmitted during SOF tag_sof--; } else { // bit is same as last bit rx[rxlen / 8] |= lastbit << (7 - (rxlen % 8)); rxlen++; } } else { // Dbprintf("DEBUG: Wierd2"); errorCount++; // Ignore wierd value, is to small to mean anything } } // if we saw over 100 wierd values break it probably isn't hitag... if (errorCount > 100) break; // We can break this loop if we received the last bit from a frame if (AT91C_BASE_TC1->TC_CV > T0 * HITAG_T_EOF) { if (rxlen > 0) break; } } // Wait some extra time for flash to be programmed if ((rxlen == 0) && (writestate == WRITE_STATE_PROG)) { AT91C_BASE_TC0->TC_CCR = AT91C_TC_SWTRG; while (AT91C_BASE_TC0->TC_CV < T0 * (HITAG_T_PROG - HITAG_T_WAIT_MAX)); } } LEDsoff(); FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF); set_tracing(false); AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKDIS; AT91C_BASE_TC0->TC_CCR = AT91C_TC_CLKDIS; StartTicks(); reply_old(CMD_ACK, bSuccessful, 0, 0, (uint8_t *)tag.sectors, 48); }