//----------------------------------------------------------------------------- // Jonathan Westhues, split Nov 2006 // // 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. //----------------------------------------------------------------------------- // Routines to support ISO 14443B. This includes both the reader software and // the `fake tag' modes. //----------------------------------------------------------------------------- #include "iso14443b.h" #define RECEIVE_SAMPLES_TIMEOUT 50000 #define ISO14443B_DMA_BUFFER_SIZE 256 // Guard Time (per 14443-2) #define TR0 0 // Synchronization time (per 14443-2) #define TR1 0 // Frame Delay Time PICC to PCD (per 14443-3 Amendment 1) #define TR2 0 // 4sample //#define SEND4STUFFBIT(x) ToSendStuffBit(x);ToSendStuffBit(x);ToSendStuffBit(x);ToSendStuffBit(x); #define SEND4STUFFBIT(x) ToSendStuffBit(x); static void switch_off(void); // the block number for the ISO14443-4 PCB (used with APDUs) static uint8_t pcb_blocknum = 0; static uint32_t iso14b_timeout = RECEIVE_SAMPLES_TIMEOUT; // param timeout is in ftw_ void iso14b_set_timeout(uint32_t timeout) { // 9.4395us = 1etu. // clock is about 1.5 us iso14b_timeout = timeout; if(MF_DBGLEVEL >= 2) Dbprintf("ISO14443B Timeout set to %ld fwt", iso14b_timeout); } static void switch_off(void){ if (MF_DBGLEVEL > 3) Dbprintf("switch_off"); FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF); SpinDelay(100); FpgaDisableSscDma(); set_tracing(FALSE); LEDsoff(); } //============================================================================= // An ISO 14443 Type B tag. We listen for commands from the reader, using // a UART kind of thing that's implemented in software. When we get a // frame (i.e., a group of bytes between SOF and EOF), we check the CRC. // If it's good, then we can do something appropriate with it, and send // a response. //============================================================================= //----------------------------------------------------------------------------- // The software UART that receives commands from the reader, and its state variables. //----------------------------------------------------------------------------- static struct { enum { STATE_UNSYNCD, STATE_GOT_FALLING_EDGE_OF_SOF, STATE_AWAITING_START_BIT, STATE_RECEIVING_DATA } state; uint16_t shiftReg; int bitCnt; int byteCnt; int byteCntMax; int posCnt; uint8_t *output; } Uart; static void UartReset() { Uart.state = STATE_UNSYNCD; Uart.shiftReg = 0; Uart.bitCnt = 0; Uart.byteCnt = 0; Uart.byteCntMax = MAX_FRAME_SIZE; Uart.posCnt = 0; } static void UartInit(uint8_t *data) { Uart.output = data; UartReset(); // memset(Uart.output, 0x00, MAX_FRAME_SIZE); } //----------------------------------------------------------------------------- // The software Demod that receives commands from the tag, and its state variables. //----------------------------------------------------------------------------- static struct { enum { DEMOD_UNSYNCD, DEMOD_PHASE_REF_TRAINING, DEMOD_AWAITING_FALLING_EDGE_OF_SOF, DEMOD_GOT_FALLING_EDGE_OF_SOF, DEMOD_AWAITING_START_BIT, DEMOD_RECEIVING_DATA } state; uint16_t bitCount; int posCount; int thisBit; /* this had been used to add RSSI (Received Signal Strength Indication) to traces. Currently not implemented. int metric; int metricN; */ uint16_t shiftReg; uint8_t *output; uint16_t len; int sumI; int sumQ; uint32_t startTime, endTime; } Demod; // Clear out the state of the "UART" that receives from the tag. static void DemodReset() { Demod.state = DEMOD_UNSYNCD; Demod.bitCount = 0; Demod.posCount = 0; Demod.thisBit = 0; Demod.shiftReg = 0; Demod.len = 0; Demod.sumI = 0; Demod.sumQ = 0; Demod.startTime = 0; Demod.endTime = 0; } static void DemodInit(uint8_t *data) { Demod.output = data; DemodReset(); // memset(Demod.output, 0x00, MAX_FRAME_SIZE); } void AppendCrc14443b(uint8_t* data, int len) { ComputeCrc14443(CRC_14443_B, data, len, data+len, data+len+1); } //----------------------------------------------------------------------------- // Code up a string of octets at layer 2 (including CRC, we don't generate // that here) so that they can be transmitted to the reader. Doesn't transmit // them yet, just leaves them ready to send in ToSend[]. //----------------------------------------------------------------------------- static void CodeIso14443bAsTag(const uint8_t *cmd, int len) { /* ISO 14443 B * * Reader to card | ASK - Amplitude Shift Keying Modulation (PCD to PICC for Type B) (NRZ-L encodig) * Card to reader | BPSK - Binary Phase Shift Keying Modulation, (PICC to PCD for Type B) * * fc - carrier frequency 13.56mHz * TR0 - Guard Time per 14443-2 * TR1 - Synchronization Time per 14443-2 * TR2 - PICC to PCD Frame Delay Time (per 14443-3 Amendment 1) * * Elementary Time Unit (ETU) is * - 128 Carrier Cycles (9.4395 µS) = 8 Subcarrier Units * - 1 ETU = 1 bit * - 10 ETU = 1 startbit, 8 databits, 1 stopbit (10bits length) * - startbit is a 0 * - stopbit is a 1 * * Start of frame (SOF) is * - [10-11] ETU of ZEROS, unmodulated time * - [2-3] ETU of ONES, * * End of frame (EOF) is * - [10-11] ETU of ZEROS, unmodulated time * * -TO VERIFY THIS BELOW- * The mode FPGA_MAJOR_MODE_HF_SIMULATOR | FPGA_HF_SIMULATOR_MODULATE_BPSK which we use to simulate tag * works like this: * - A 1-bit input to the FPGA becomes 8 pulses at 847.5kHz (9.44µS) * - A 0-bit input to the FPGA becomes an unmodulated time of 9.44µS * * * * Card sends data ub 847.e kHz subcarrier * 848k = 9.44µS = 128 fc * 424k = 18.88µS = 256 fc * 212k = 37.76µS = 512 fc * 106k = 75.52µS = 1024 fc * * Reader data transmission: * - no modulation ONES * - SOF * - Command, data and CRC_B * - EOF * - no modulation ONES * * Card data transmission * - TR1 * - SOF * - data (each bytes is: 1startbit,8bits, 1stopbit) * - CRC_B * - EOF * * FPGA implementation : * At this point only Type A is implemented. This means that we are using a * bit rate of 106 kbit/s, or fc/128. Oversample by 4, which ought to make * things practical for the ARM (fc/32, 423.8 kbits/s, ~50 kbytes/s) * */ // ToSendStuffBit, 40 calls // 1 ETU = 1startbit, 1stopbit, 8databits == 10bits. // 1 ETU = 10 * 4 == 40 stuffbits ( ETU_TAG_BIT ) int i,j; uint8_t b; ToSendReset(); // Transmit a burst of ones, as the initial thing that lets the // reader get phase sync. // This loop is TR1, per specification // TR1 minimum must be > 80/fs // TR1 maximum 200/fs // 80/fs < TR1 < 200/fs // 10 ETU < TR1 < 24 ETU // Send SOF. // 10-11 ETU * 4times samples ZEROS for(i = 0; i < 10; i++) { SEND4STUFFBIT(0); } // 2-3 ETU * 4times samples ONES for(i = 0; i < 3; i++) { SEND4STUFFBIT(1); } // data for(i = 0; i < len; ++i) { // Start bit SEND4STUFFBIT(0); // Data bits b = cmd[i]; for(j = 0; j < 8; ++j) { if(b & 1) { SEND4STUFFBIT(1); } else { SEND4STUFFBIT(0); } b >>= 1; } // Stop bit SEND4STUFFBIT(1); // Extra Guard bit // For PICC it ranges 0-18us (1etu = 9us) SEND4STUFFBIT(1); } // Send EOF. // 10-11 ETU * 4 sample rate = ZEROS for(i = 0; i < 10; i++) { SEND4STUFFBIT(0); } // why this? for(i = 0; i < 40; i++) { SEND4STUFFBIT(1); } // Convert from last byte pos to length ++ToSendMax; } /* Receive & handle a bit coming from the reader. * * This function is called 4 times per bit (every 2 subcarrier cycles). * Subcarrier frequency fs is 848kHz, 1/fs = 1,18us, i.e. function is called every 2,36us * * LED handling: * LED A -> ON once we have received the SOF and are expecting the rest. * LED A -> OFF once we have received EOF or are in error state or unsynced * * Returns: true if we received a EOF * false if we are still waiting for some more */ static RAMFUNC int Handle14443bReaderUartBit(uint8_t bit) { switch(Uart.state) { case STATE_UNSYNCD: if(!bit) { // we went low, so this could be the beginning of an SOF Uart.state = STATE_GOT_FALLING_EDGE_OF_SOF; Uart.posCnt = 0; Uart.bitCnt = 0; } break; case STATE_GOT_FALLING_EDGE_OF_SOF: Uart.posCnt++; if(Uart.posCnt == 2) { // sample every 4 1/fs in the middle of a bit if(bit) { if(Uart.bitCnt > 9) { // we've seen enough consecutive // zeros that it's a valid SOF Uart.posCnt = 0; Uart.byteCnt = 0; Uart.state = STATE_AWAITING_START_BIT; LED_A_ON(); // Indicate we got a valid SOF } else { // didn't stay down long enough // before going high, error Uart.state = STATE_UNSYNCD; } } else { // do nothing, keep waiting } Uart.bitCnt++; } if(Uart.posCnt >= 4) Uart.posCnt = 0; if(Uart.bitCnt > 12) { // Give up if we see too many zeros without // a one, too. LED_A_OFF(); Uart.state = STATE_UNSYNCD; } break; case STATE_AWAITING_START_BIT: Uart.posCnt++; if(bit) { if(Uart.posCnt > 50/2) { // max 57us between characters = 49 1/fs, max 3 etus after low phase of SOF = 24 1/fs // stayed high for too long between // characters, error Uart.state = STATE_UNSYNCD; } } else { // falling edge, this starts the data byte Uart.posCnt = 0; Uart.bitCnt = 0; Uart.shiftReg = 0; Uart.state = STATE_RECEIVING_DATA; } break; case STATE_RECEIVING_DATA: Uart.posCnt++; if(Uart.posCnt == 2) { // time to sample a bit Uart.shiftReg >>= 1; if(bit) { Uart.shiftReg |= 0x200; } Uart.bitCnt++; } if(Uart.posCnt >= 4) { Uart.posCnt = 0; } if(Uart.bitCnt == 10) { if((Uart.shiftReg & 0x200) && !(Uart.shiftReg & 0x001)) { // this is a data byte, with correct // start and stop bits Uart.output[Uart.byteCnt] = (Uart.shiftReg >> 1) & 0xff; Uart.byteCnt++; if(Uart.byteCnt >= Uart.byteCntMax) { // Buffer overflowed, give up LED_A_OFF(); Uart.state = STATE_UNSYNCD; } else { // so get the next byte now Uart.posCnt = 0; Uart.state = STATE_AWAITING_START_BIT; } } else if (Uart.shiftReg == 0x000) { // this is an EOF byte LED_A_OFF(); // Finished receiving Uart.state = STATE_UNSYNCD; if (Uart.byteCnt != 0) { return TRUE; } } else { // this is an error LED_A_OFF(); Uart.state = STATE_UNSYNCD; } } break; default: LED_A_OFF(); Uart.state = STATE_UNSYNCD; break; } return FALSE; } //----------------------------------------------------------------------------- // Receive a command (from the reader to us, where we are the simulated tag), // and store it in the given buffer, up to the given maximum length. Keeps // spinning, waiting for a well-framed command, until either we get one // (returns TRUE) or someone presses the pushbutton on the board (FALSE). // // Assume that we're called with the SSC (to the FPGA) and ADC path set // correctly. //----------------------------------------------------------------------------- static int GetIso14443bCommandFromReader(uint8_t *received, uint16_t *len) { // Set FPGA mode to "simulated ISO 14443B tag", no modulation (listen // only, since we are receiving, not transmitting). // Signal field is off with the appropriate LED LED_D_OFF(); FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_SIMULATOR | FPGA_HF_SIMULATOR_NO_MODULATION); StartCountSspClk(); volatile uint8_t b; // clear receiving shift register and holding register // What does this loop do? Is it TR1? for(uint8_t c = 0; c < 10;) { if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) { AT91C_BASE_SSC->SSC_THR = 0xFF; ++c; } } // Now run a `software UART' on the stream of incoming samples. UartInit(received); b = 0; uint8_t mask; while( !BUTTON_PRESS() ) { WDT_HIT(); if ( AT91C_BASE_SSC->SSC_SR & AT91C_SSC_RXRDY ) { b = (uint8_t) AT91C_BASE_SSC->SSC_RHR; for ( mask = 0x80; mask != 0; mask >>= 1) { if ( Handle14443bReaderUartBit(b & mask)) { *len = Uart.byteCnt; return TRUE; } } } } return FALSE; } void ClearFpgaShiftingRegisters(void){ volatile uint8_t b; // clear receiving shift register and holding register while(!(AT91C_BASE_SSC->SSC_SR & AT91C_SSC_RXRDY)); b = AT91C_BASE_SSC->SSC_RHR; (void) b; while(!(AT91C_BASE_SSC->SSC_SR & AT91C_SSC_RXRDY)); b = AT91C_BASE_SSC->SSC_RHR; (void) b; // wait for the FPGA to signal fdt_indicator == 1 (the FPGA is ready to queue new data in its delay line) for (uint8_t j = 0; j < 5; j++) { // allow timeout - better late than never while(!(AT91C_BASE_SSC->SSC_SR & AT91C_SSC_RXRDY)); if (AT91C_BASE_SSC->SSC_RHR) break; } // Clear TXRDY: AT91C_BASE_SSC->SSC_THR = 0xFF; } void WaitForFpgaDelayQueueIsEmpty( uint16_t delay ){ // Ensure that the FPGA Delay Queue is empty before we switch to TAGSIM_LISTEN again: uint8_t fpga_queued_bits = delay >> 3; // twich /8 ?? >>3, for (uint8_t i = 0; i <= fpga_queued_bits/8 + 1; ) { if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) { AT91C_BASE_SSC->SSC_THR = 0xFF; i++; } } } static void TransmitFor14443b_AsTag( uint8_t *response, uint16_t len) { // Signal field is off with the appropriate LED LED_D_OFF(); uint16_t fpgasendQueueDelay = 0; // Modulate BPSK FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_SIMULATOR | FPGA_HF_SIMULATOR_MODULATE_BPSK); ClearFpgaShiftingRegisters(); FpgaSetupSsc(); // Transmit the response. for(uint16_t i = 0; i < len;) { if(AT91C_BASE_SSC->SSC_SR & AT91C_SSC_TXRDY) { AT91C_BASE_SSC->SSC_THR = response[++i]; fpgasendQueueDelay = (uint8_t)AT91C_BASE_SSC->SSC_RHR; } } WaitForFpgaDelayQueueIsEmpty(fpgasendQueueDelay); } //----------------------------------------------------------------------------- // Main loop of simulated tag: receive commands from reader, decide what // response to send, and send it. //----------------------------------------------------------------------------- void SimulateIso14443bTag(uint32_t pupi) { ///////////// setup device. FpgaDownloadAndGo(FPGA_BITSTREAM_HF); // allocate command receive buffer BigBuf_free(); BigBuf_Clear_ext(false); clear_trace(); //sim set_tracing(TRUE); // connect Demodulated Signal to ADC: SetAdcMuxFor(GPIO_MUXSEL_HIPKD); // Set up the synchronous serial port FpgaSetupSsc(); ///////////// uint16_t len, cmdsReceived = 0; int cardSTATE = SIM_NOFIELD; int vHf = 0; // in mV // uint32_t time_0 = 0; // uint32_t t2r_time = 0; // uint32_t r2t_time = 0; uint8_t *receivedCmd = BigBuf_malloc(MAX_FRAME_SIZE); // the only commands we understand is WUPB, AFI=0, Select All, N=1: // static const uint8_t cmdWUPB[] = { ISO14443B_REQB, 0x00, 0x08, 0x39, 0x73 }; // WUPB // ... and REQB, AFI=0, Normal Request, N=1: // static const uint8_t cmdREQB[] = { ISO14443B_REQB, 0x00, 0x00, 0x71, 0xFF }; // REQB // ... and ATTRIB // static const uint8_t cmdATTRIB[] = { ISO14443B_ATTRIB, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff}; // ATTRIB // ... if not PUPI/UID is supplied we always respond with ATQB, PUPI = 820de174, Application Data = 0x20381922, // supports only 106kBit/s in both directions, max frame size = 32Bytes, // supports ISO14443-4, FWI=8 (77ms), NAD supported, CID not supported: uint8_t respATQB[] = { 0x50, 0x82, 0x0d, 0xe1, 0x74, 0x20, 0x38, 0x19, 0x22, 0x00, 0x21, 0x85, 0x5e, 0xd7 }; // response to HLTB and ATTRIB static const uint8_t respOK[] = {0x00, 0x78, 0xF0}; // ...PUPI/UID supplied from user. Adjust ATQB response accordingly if ( pupi > 0 ) { num_to_bytes(pupi, 4, respATQB+1); ComputeCrc14443(CRC_14443_B, respATQB, 12, respATQB+13, respATQB+14); } // prepare "ATQB" tag answer (encoded): CodeIso14443bAsTag(respATQB, sizeof(respATQB)); uint8_t *encodedATQB = BigBuf_malloc(ToSendMax); uint16_t encodedATQBLen = ToSendMax; memcpy(encodedATQB, ToSend, ToSendMax); // prepare "OK" tag answer (encoded): CodeIso14443bAsTag(respOK, sizeof(respOK)); uint8_t *encodedOK = BigBuf_malloc(ToSendMax); uint16_t encodedOKLen = ToSendMax; memcpy(encodedOK, ToSend, ToSendMax); // Simulation loop while (!BUTTON_PRESS() && !usb_poll_validate_length()) { WDT_HIT(); // find reader field if (cardSTATE == SIM_NOFIELD) { vHf = (MAX_ADC_HF_VOLTAGE * AvgAdc(ADC_CHAN_HF)) >> 10; if ( vHf > MF_MINFIELDV ) { cardSTATE = SIM_IDLE; LED_A_ON(); } } if (cardSTATE == SIM_NOFIELD) continue; // Get reader command if (!GetIso14443bCommandFromReader(receivedCmd, &len)) { Dbprintf("button pressed, received %d commands", cmdsReceived); break; } // ISO14443-B protocol states: // REQ or WUP request in ANY state // WUP in HALTED state if (len == 5 ) { if ( (receivedCmd[0] == ISO14443B_REQB && (receivedCmd[2] & 0x8)== 0x8 && cardSTATE == SIM_HALTED) || receivedCmd[0] == ISO14443B_REQB ){ LogTrace(receivedCmd, len, 0, 0, NULL, TRUE); cardSTATE = SIM_SELECTING; } } /* * How should this flow go? * REQB or WUPB * send response ( waiting for Attrib) * ATTRIB * send response ( waiting for commands 7816) * HALT send halt response ( waiting for wupb ) */ switch(cardSTATE){ case SIM_NOFIELD: case SIM_HALTED: case SIM_IDLE:{ LogTrace(receivedCmd, len, 0, 0, NULL, TRUE); break; } case SIM_SELECTING: { TransmitFor14443b_AsTag( encodedATQB, encodedATQBLen ); LogTrace(respATQB, sizeof(respATQB), 0, 0, NULL, FALSE); cardSTATE = SIM_WORK; break; } case SIM_HALTING: { TransmitFor14443b_AsTag( encodedOK, encodedOKLen ); LogTrace(respOK, sizeof(respOK), 0, 0, NULL, FALSE); cardSTATE = SIM_HALTED; break; } case SIM_ACKNOWLEDGE:{ TransmitFor14443b_AsTag( encodedOK, encodedOKLen ); LogTrace(respOK, sizeof(respOK), 0, 0, NULL, FALSE); cardSTATE = SIM_IDLE; break; } case SIM_WORK:{ if ( len == 7 && receivedCmd[0] == ISO14443B_HALT ) { cardSTATE = SIM_HALTED; } else if ( len == 11 && receivedCmd[0] == ISO14443B_ATTRIB ) { cardSTATE = SIM_ACKNOWLEDGE; } else { // Todo: // - SLOT MARKER // - ISO7816 // - emulate with a memory dump Dbprintf("new cmd from reader: len=%d, cmdsRecvd=%d", len, cmdsReceived); // CRC Check uint8_t b1, b2; if (len >= 3){ // if crc exists ComputeCrc14443(CRC_14443_B, receivedCmd, len-2, &b1, &b2); if(b1 != receivedCmd[len-2] || b2 != receivedCmd[len-1]) DbpString("+++CRC fail"); else DbpString("CRC passes"); } cardSTATE = SIM_IDLE; } break; } default: break; } ++cmdsReceived; if(cmdsReceived > 1000) { DbpString("14B Simulate, 1000 commands later..."); break; } } if (MF_DBGLEVEL >= 1) Dbprintf("Emulator stopped. Tracing: %d trace length: %d ", tracing, BigBuf_get_traceLen()); switch_off(); //simulate } //============================================================================= // An ISO 14443 Type B reader. We take layer two commands, code them // appropriately, and then send them to the tag. We then listen for the // tag's response, which we leave in the buffer to be demodulated on the // PC side. //============================================================================= /* * Handles reception of a bit from the tag * * This function is called 2 times per bit (every 4 subcarrier cycles). * Subcarrier frequency fs is 848kHz, 1/fs = 1,18us, i.e. function is called every 4,72us * * LED handling: * LED C -> ON once we have received the SOF and are expecting the rest. * LED C -> OFF once we have received EOF or are unsynced * * Returns: true if we received a EOF * false if we are still waiting for some more * */ #ifndef SUBCARRIER_DETECT_THRESHOLD # define SUBCARRIER_DETECT_THRESHOLD 8 #endif static RAMFUNC int Handle14443bTagSamplesDemod(int ci, int cq) { int v=0;// , myI, myQ = 0; // The soft decision on the bit uses an estimate of just the // quadrant of the reference angle, not the exact angle. #define MAKE_SOFT_DECISION() { \ if(Demod.sumI > 0) { \ v = ci; \ } else { \ v = -ci; \ } \ if(Demod.sumQ > 0) { \ v += cq; \ } else { \ v -= cq; \ } \ } // Subcarrier amplitude v = sqrt(ci^2 + cq^2), approximated here by abs(ci) + abs(cq) // Subcarrier amplitude v = sqrt(ci^2 + cq^2), approximated here by max(abs(ci),abs(cq)) + 1/2*min(abs(ci),abs(cq))) #define CHECK_FOR_SUBCARRIER() { \ if(ci < 0) { \ if(cq < 0) { /* ci < 0, cq < 0 */ \ if (cq < ci) { \ v = -cq - (ci >> 1); \ } else { \ v = -ci - (cq >> 1); \ } \ } else { /* ci < 0, cq >= 0 */ \ if (cq < -ci) { \ v = -ci + (cq >> 1); \ } else { \ v = cq - (ci >> 1); \ } \ } \ } else { \ if(cq < 0) { /* ci >= 0, cq < 0 */ \ if (-cq < ci) { \ v = ci - (cq >> 1); \ } else { \ v = -cq + (ci >> 1); \ } \ } else { /* ci >= 0, cq >= 0 */ \ if (cq < ci) { \ v = ci + (cq >> 1); \ } else { \ v = cq + (ci >> 1); \ } \ } \ } \ } //note: couldn't we just use MAX(ABS(ci),ABS(cq)) + (MIN(ABS(ci),ABS(cq))/2) from common.h - marshmellow #define CHECK_FOR_SUBCARRIER_un() { \ myI = ABS(ci); \ myQ = ABS(cq); \ v = MAX(myI,myQ) + (MIN(myI,myQ) >> 1); \ } switch(Demod.state) { case DEMOD_UNSYNCD: CHECK_FOR_SUBCARRIER(); // subcarrier detected if(v > SUBCARRIER_DETECT_THRESHOLD) { Demod.state = DEMOD_PHASE_REF_TRAINING; Demod.sumI = ci; Demod.sumQ = cq; Demod.posCount = 1; } break; case DEMOD_PHASE_REF_TRAINING: if(Demod.posCount < 8) { CHECK_FOR_SUBCARRIER(); if (v > SUBCARRIER_DETECT_THRESHOLD) { // set the reference phase (will code a logic '1') by averaging over 32 1/fs. // note: synchronization time > 80 1/fs Demod.sumI += ci; Demod.sumQ += cq; ++Demod.posCount; } else { // subcarrier lost Demod.state = DEMOD_UNSYNCD; } } else { Demod.state = DEMOD_AWAITING_FALLING_EDGE_OF_SOF; } break; case DEMOD_AWAITING_FALLING_EDGE_OF_SOF: MAKE_SOFT_DECISION(); if(v < 0) { // logic '0' detected Demod.state = DEMOD_GOT_FALLING_EDGE_OF_SOF; Demod.posCount = 0; // start of SOF sequence } else { // maximum length of TR1 = 200 1/fs if(Demod.posCount > 25*2) Demod.state = DEMOD_UNSYNCD; } ++Demod.posCount; break; case DEMOD_GOT_FALLING_EDGE_OF_SOF: ++Demod.posCount; MAKE_SOFT_DECISION(); if(v > 0) { // low phase of SOF too short (< 9 etu). Note: spec is >= 10, but FPGA tends to "smear" edges if(Demod.posCount < 9*2) { Demod.state = DEMOD_UNSYNCD; } else { LED_C_ON(); // Got SOF Demod.startTime = GetCountSspClk(); Demod.state = DEMOD_AWAITING_START_BIT; Demod.posCount = 0; Demod.len = 0; } } else { // low phase of SOF too long (> 12 etu) if (Demod.posCount > 12*2) { Demod.state = DEMOD_UNSYNCD; LED_C_OFF(); } } break; case DEMOD_AWAITING_START_BIT: ++Demod.posCount; MAKE_SOFT_DECISION(); if (v > 0) { if(Demod.posCount > 3*2) { // max 19us between characters = 16 1/fs, max 3 etu after low phase of SOF = 24 1/fs Demod.state = DEMOD_UNSYNCD; LED_C_OFF(); } } else { // start bit detected Demod.bitCount = 0; Demod.posCount = 1; // this was the first half Demod.thisBit = v; Demod.shiftReg = 0; Demod.state = DEMOD_RECEIVING_DATA; } break; case DEMOD_RECEIVING_DATA: MAKE_SOFT_DECISION(); if (Demod.posCount == 0) { // first half of bit Demod.thisBit = v; Demod.posCount = 1; } else { // second half of bit Demod.thisBit += v; Demod.shiftReg >>= 1; // logic '1' if(Demod.thisBit > 0) Demod.shiftReg |= 0x200; ++Demod.bitCount; if(Demod.bitCount == 10) { uint16_t s = Demod.shiftReg; // stop bit == '1', start bit == '0' if((s & 0x200) && !(s & 0x001)) { uint8_t b = (s >> 1); Demod.output[Demod.len] = b; ++Demod.len; Demod.state = DEMOD_AWAITING_START_BIT; } else { Demod.state = DEMOD_UNSYNCD; Demod.endTime = GetCountSspClk(); LED_C_OFF(); // This is EOF (start, stop and all data bits == '0' if(s == 0) return TRUE; } } Demod.posCount = 0; } break; default: Demod.state = DEMOD_UNSYNCD; LED_C_OFF(); break; } return FALSE; } /* * Demodulate the samples we received from the tag, also log to tracebuffer * quiet: set to 'TRUE' to disable debug output */ static void GetTagSamplesFor14443bDemod() { bool gotFrame = FALSE; int lastRxCounter = ISO14443B_DMA_BUFFER_SIZE; int max = 0, ci = 0, cq = 0, samples = 0; uint32_t time_0 = 0, time_stop = 0; BigBuf_free(); // Set up the demodulator for tag -> reader responses. DemodInit(BigBuf_malloc(MAX_FRAME_SIZE)); // The DMA buffer, used to stream samples from the FPGA int8_t *dmaBuf = (int8_t*) BigBuf_malloc(ISO14443B_DMA_BUFFER_SIZE); int8_t *upTo = dmaBuf; // Setup and start DMA. if ( !FpgaSetupSscDma((uint8_t*) dmaBuf, ISO14443B_DMA_BUFFER_SIZE) ){ if (MF_DBGLEVEL > 1) Dbprintf("FpgaSetupSscDma failed. Exiting"); return; } time_0 = GetCountSspClk(); // And put the FPGA in the appropriate mode FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_READER_RX_XCORR | FPGA_HF_READER_RX_XCORR_848_KHZ); while( !BUTTON_PRESS() ) { WDT_HIT(); int behindBy = lastRxCounter - AT91C_BASE_PDC_SSC->PDC_RCR; if(behindBy > max) max = behindBy; // rx counter - dma counter? (how much?) & (mod) dma buff / 2. (since 2bytes at the time is read) while(((lastRxCounter - AT91C_BASE_PDC_SSC->PDC_RCR) & (ISO14443B_DMA_BUFFER_SIZE-1)) > 2) { ci = upTo[0]; cq = upTo[1]; upTo += 2; samples += 2; // restart DMA buffer to receive again. if(upTo >= dmaBuf + ISO14443B_DMA_BUFFER_SIZE) { upTo = dmaBuf; AT91C_BASE_PDC_SSC->PDC_RNPR = (uint32_t) upTo; AT91C_BASE_PDC_SSC->PDC_RNCR = ISO14443B_DMA_BUFFER_SIZE; } lastRxCounter -= 2; if(lastRxCounter <= 0) lastRxCounter += ISO14443B_DMA_BUFFER_SIZE; // is this | 0x01 the error? & 0xfe in https://github.com/Proxmark/proxmark3/issues/103 //gotFrame = Handle14443bTagSamplesDemod(ci & 0xfe, cq & 0xfe); gotFrame = Handle14443bTagSamplesDemod(ci, cq); if ( gotFrame ) break; LED_A_INV(); } time_stop = GetCountSspClk() - time_0; if(time_stop > iso14b_timeout || gotFrame) break; } FpgaDisableSscDma(); if (MF_DBGLEVEL >= 3) { Dbprintf("max behindby = %d, samples = %d, gotFrame = %s, Demod.state = %d, Demod.len = %u", max, samples, (gotFrame) ? "true" : "false", Demod.state, Demod.len ); } if ( Demod.len > 0 ) LogTrace(Demod.output, Demod.len, Demod.startTime, Demod.endTime, NULL, FALSE); } //----------------------------------------------------------------------------- // Transmit the command (to the tag) that was placed in ToSend[]. //----------------------------------------------------------------------------- static void TransmitFor14443b_AsReader(void) { FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_READER_TX | FPGA_HF_READER_TX_SHALLOW_MOD); SpinDelay(20); int c; // we could been in following mode: // FPGA_MAJOR_MODE_HF_READER_RX_XCORR | FPGA_HF_READER_RX_XCORR_848_KHZ // if its second call or more // What does this loop do? Is it TR1? for(c = 0; c < 10;) { if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) { AT91C_BASE_SSC->SSC_THR = 0xFF; ++c; } } // Send frame loop for(c = 0; c < ToSendMax;) { if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) { AT91C_BASE_SSC->SSC_THR = ToSend[c]; ++c; } } WDT_HIT(); } //----------------------------------------------------------------------------- // Code a layer 2 command (string of octets, including CRC) into ToSend[], // so that it is ready to transmit to the tag using TransmitFor14443b(). //----------------------------------------------------------------------------- static void CodeIso14443bAsReader(const uint8_t *cmd, int len) { /* * Reader data transmission: * - no modulation ONES * - SOF * - Command, data and CRC_B * - EOF * - no modulation ONES * * 1 ETU == 1 BIT! * TR0 - 8 ETUS minimum. */ int i; uint8_t b; ToSendReset(); // Send SOF // 10-11 ETUs of ZERO for(i = 0; i < 10; ++i) ToSendStuffBit(0); // 2-3 ETUs of ONE ToSendStuffBit(1); ToSendStuffBit(1); ToSendStuffBit(1); // Sending cmd, LSB // from here we add BITS for(i = 0; i < len; ++i) { // Start bit ToSendStuffBit(0); // Data bits b = cmd[i]; if ( b & 1 ) ToSendStuffBit(1); else ToSendStuffBit(0); if ( (b>>1) & 1) ToSendStuffBit(1); else ToSendStuffBit(0); if ( (b>>2) & 1) ToSendStuffBit(1); else ToSendStuffBit(0); if ( (b>>3) & 1) ToSendStuffBit(1); else ToSendStuffBit(0); if ( (b>>4) & 1) ToSendStuffBit(1); else ToSendStuffBit(0); if ( (b>>5) & 1) ToSendStuffBit(1); else ToSendStuffBit(0); if ( (b>>6) & 1) ToSendStuffBit(1); else ToSendStuffBit(0); if ( (b>>7) & 1) ToSendStuffBit(1); else ToSendStuffBit(0); // Stop bit ToSendStuffBit(1); // EGT extra guard time // For PCD it ranges 0-57us (1etu = 9us) ToSendStuffBit(1); ToSendStuffBit(1); ToSendStuffBit(1); } // Send EOF // 10-11 ETUs of ZERO for(i = 0; i < 10; ++i) ToSendStuffBit(0); // Transition time. TR0 - guard time // 8ETUS minum? // Per specification, Subcarrier must be stopped no later than 2 ETUs after EOF. for(i = 0; i < 40 ; ++i) ToSendStuffBit(1); // TR1 - Synchronization time // Convert from last character reference to length ++ToSendMax; } /** Convenience function to encode, transmit and trace iso 14443b comms **/ static void CodeAndTransmit14443bAsReader(const uint8_t *cmd, int len) { CodeIso14443bAsReader(cmd, len); uint32_t time_start = GetCountSspClk(); TransmitFor14443b_AsReader(); if(trigger) LED_A_ON(); LogTrace(cmd, len, time_start, GetCountSspClk()-time_start, NULL, TRUE); } /* Sends an APDU to the tag * TODO: check CRC and preamble */ uint8_t iso14443b_apdu(uint8_t const *message, size_t message_length, uint8_t *response) { uint8_t crc[2] = {0x00, 0x00}; uint8_t message_frame[message_length + 4]; // PCB message_frame[0] = 0x0A | pcb_blocknum; pcb_blocknum ^= 1; // CID message_frame[1] = 0; // INF memcpy(message_frame + 2, message, message_length); // EDC (CRC) ComputeCrc14443(CRC_14443_B, message_frame, message_length + 2, &message_frame[message_length + 2], &message_frame[message_length + 3]); // send CodeAndTransmit14443bAsReader(message_frame, message_length + 4); //no // get response GetTagSamplesFor14443bDemod(); //no if(Demod.len < 3) return 0; // VALIDATE CRC ComputeCrc14443(CRC_14443_B, Demod.output, Demod.len-2, &crc[0], &crc[1]); if ( crc[0] != Demod.output[Demod.len-2] || crc[1] != Demod.output[Demod.len-1] ) return 0; // copy response contents if(response != NULL) memcpy(response, Demod.output, Demod.len); return Demod.len; } /** * SRx Initialise. */ uint8_t iso14443b_select_srx_card(iso14b_card_select_t *card ) { // INITIATE command: wake up the tag using the INITIATE static const uint8_t init_srx[] = { ISO14443B_INITIATE, 0x00, 0x97, 0x5b }; // SELECT command (with space for CRC) uint8_t select_srx[] = { ISO14443B_SELECT, 0x00, 0x00, 0x00}; // temp to calc crc. uint8_t crc[2] = {0x00, 0x00}; CodeAndTransmit14443bAsReader(init_srx, sizeof(init_srx)); GetTagSamplesFor14443bDemod(); //no if (Demod.len == 0) return 2; // Randomly generated Chip ID if (card) card->chipid = Demod.output[0]; select_srx[1] = Demod.output[0]; ComputeCrc14443(CRC_14443_B, select_srx, 2, &select_srx[2], &select_srx[3]); CodeAndTransmit14443bAsReader(select_srx, sizeof(select_srx)); GetTagSamplesFor14443bDemod(); //no if (Demod.len != 3) return 2; // Check the CRC of the answer: ComputeCrc14443(CRC_14443_B, Demod.output, Demod.len-2 , &crc[0], &crc[1]); if(crc[0] != Demod.output[1] || crc[1] != Demod.output[2]) return 3; // Check response from the tag: should be the same UID as the command we just sent: if (select_srx[1] != Demod.output[0]) return 1; // First get the tag's UID: select_srx[0] = ISO14443B_GET_UID; ComputeCrc14443(CRC_14443_B, select_srx, 1 , &select_srx[1], &select_srx[2]); CodeAndTransmit14443bAsReader(select_srx, 3); // Only first three bytes for this one GetTagSamplesFor14443bDemod(); //no if (Demod.len != 10) return 2; // The check the CRC of the answer ComputeCrc14443(CRC_14443_B, Demod.output, Demod.len-2, &crc[0], &crc[1]); if(crc[0] != Demod.output[8] || crc[1] != Demod.output[9]) return 3; if (card) { card->uidlen = 8; memcpy(card->uid, Demod.output, 8); } return 0; } /* Perform the ISO 14443 B Card Selection procedure * Currently does NOT do any collision handling. * It expects 0-1 cards in the device's range. * TODO: Support multiple cards (perform anticollision) * TODO: Verify CRC checksums */ uint8_t iso14443b_select_card(iso14b_card_select_t *card ) { // WUPB command (including CRC) // Note: WUPB wakes up all tags, REQB doesn't wake up tags in HALT state static const uint8_t wupb[] = { ISO14443B_REQB, 0x00, 0x08, 0x39, 0x73 }; // ATTRIB command (with space for CRC) uint8_t attrib[] = { ISO14443B_ATTRIB, 0x00, 0x00, 0x00, 0x00, 0x00, 0x08, 0x00, 0x00, 0x00, 0x00}; // temp to calc crc. uint8_t crc[2] = {0x00, 0x00}; // first, wake up the tag CodeAndTransmit14443bAsReader(wupb, sizeof(wupb)); GetTagSamplesFor14443bDemod(); //select_card // ATQB too short? if (Demod.len < 14) return 2; // VALIDATE CRC ComputeCrc14443(CRC_14443_B, Demod.output, Demod.len-2, &crc[0], &crc[1]); if ( crc[0] != Demod.output[12] || crc[1] != Demod.output[13] ) return 3; if (card) { card->uidlen = 4; memcpy(card->uid, Demod.output+1, 4); memcpy(card->atqb, Demod.output+5, 7); } // copy the PUPI to ATTRIB ( PUPI == UID ) memcpy(attrib + 1, Demod.output + 1, 4); // copy the protocol info from ATQB (Protocol Info -> Protocol_Type) into ATTRIB (Param 3) attrib[7] = Demod.output[10] & 0x0F; ComputeCrc14443(CRC_14443_B, attrib, 9, attrib + 9, attrib + 10); CodeAndTransmit14443bAsReader(attrib, sizeof(attrib)); GetTagSamplesFor14443bDemod();//select_card // Answer to ATTRIB too short? if(Demod.len < 3) return 2; // VALIDATE CRC ComputeCrc14443(CRC_14443_B, Demod.output, Demod.len-2, &crc[0], &crc[1]); if ( crc[0] != Demod.output[1] || crc[1] != Demod.output[2] ) return 3; // CID if (card) card->cid = Demod.output[0]; uint8_t fwt = card->atqb[6]>>4; if ( fwt < 16 ){ uint32_t fwt_time = (302 << fwt); iso14b_set_timeout( fwt_time); } // reset PCB block number pcb_blocknum = 0; return 0; } // Set up ISO 14443 Type B communication (similar to iso14443a_setup) // field is setup for "Sending as Reader" void iso14443b_setup() { if (MF_DBGLEVEL > 3) Dbprintf("iso1443b_setup Enter"); LEDsoff(); FpgaDownloadAndGo(FPGA_BITSTREAM_HF); //BigBuf_free(); //BigBuf_Clear_ext(false); // Initialize Demod and Uart structs DemodInit(BigBuf_malloc(MAX_FRAME_SIZE)); UartInit(BigBuf_malloc(MAX_FRAME_SIZE)); // connect Demodulated Signal to ADC: SetAdcMuxFor(GPIO_MUXSEL_HIPKD); // Set up the synchronous serial port FpgaSetupSsc(); // Signal field is on with the appropriate LED FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_READER_TX | FPGA_HF_READER_TX_SHALLOW_MOD); SpinDelay(100); // Start the timer StartCountSspClk(); LED_D_ON(); if (MF_DBGLEVEL > 3) Dbprintf("iso1443b_setup Exit"); } //----------------------------------------------------------------------------- // Read a SRI512 ISO 14443B tag. // // SRI512 tags are just simple memory tags, here we're looking at making a dump // of the contents of the memory. No anticollision algorithm is done, we assume // we have a single tag in the field. // // I tried to be systematic and check every answer of the tag, every CRC, etc... //----------------------------------------------------------------------------- void ReadSTMemoryIso14443b(uint8_t numofblocks) { FpgaDownloadAndGo(FPGA_BITSTREAM_HF); // Make sure that we start from off, since the tags are stateful; // confusing things will happen if we don't reset them between reads. switch_off(); // before ReadStMemory set_tracing(TRUE); uint8_t i = 0x00; SetAdcMuxFor(GPIO_MUXSEL_HIPKD); FpgaSetupSsc(); // Now give it time to spin up. // Signal field is on with the appropriate LED LED_D_ON(); FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_READER_RX_XCORR | FPGA_HF_READER_RX_XCORR_848_KHZ); SpinDelay(20); // First command: wake up the tag using the INITIATE command uint8_t cmd1[] = {ISO14443B_INITIATE, 0x00, 0x97, 0x5b}; CodeAndTransmit14443bAsReader(cmd1, sizeof(cmd1)); //no GetTagSamplesFor14443bDemod(); // no if (Demod.len == 0) { DbpString("No response from tag"); set_tracing(FALSE); return; } else { Dbprintf("Randomly generated Chip ID (+ 2 byte CRC): %02x %02x %02x", Demod.output[0], Demod.output[1], Demod.output[2]); } // There is a response, SELECT the uid DbpString("Now SELECT tag:"); cmd1[0] = ISO14443B_SELECT; // 0x0E is SELECT cmd1[1] = Demod.output[0]; ComputeCrc14443(CRC_14443_B, cmd1, 2, &cmd1[2], &cmd1[3]); CodeAndTransmit14443bAsReader(cmd1, sizeof(cmd1)); //no GetTagSamplesFor14443bDemod(); //no if (Demod.len != 3) { Dbprintf("Expected 3 bytes from tag, got %d", Demod.len); set_tracing(FALSE); return; } // Check the CRC of the answer: ComputeCrc14443(CRC_14443_B, Demod.output, 1 , &cmd1[2], &cmd1[3]); if(cmd1[2] != Demod.output[1] || cmd1[3] != Demod.output[2]) { DbpString("CRC Error reading select response."); set_tracing(FALSE); return; } // Check response from the tag: should be the same UID as the command we just sent: if (cmd1[1] != Demod.output[0]) { Dbprintf("Bad response to SELECT from Tag, aborting: %02x %02x", cmd1[1], Demod.output[0]); set_tracing(FALSE); return; } // Tag is now selected, // First get the tag's UID: cmd1[0] = ISO14443B_GET_UID; ComputeCrc14443(CRC_14443_B, cmd1, 1 , &cmd1[1], &cmd1[2]); CodeAndTransmit14443bAsReader(cmd1, 3); // no -- Only first three bytes for this one GetTagSamplesFor14443bDemod(); //no if (Demod.len != 10) { Dbprintf("Expected 10 bytes from tag, got %d", Demod.len); set_tracing(FALSE); return; } // The check the CRC of the answer (use cmd1 as temporary variable): ComputeCrc14443(CRC_14443_B, Demod.output, 8, &cmd1[2], &cmd1[3]); if(cmd1[2] != Demod.output[8] || cmd1[3] != Demod.output[9]) { Dbprintf("CRC Error reading block! Expected: %04x got: %04x", (cmd1[2]<<8)+cmd1[3], (Demod.output[8]<<8)+Demod.output[9]); // Do not return;, let's go on... (we should retry, maybe ?) } Dbprintf("Tag UID (64 bits): %08x %08x", (Demod.output[7]<<24) + (Demod.output[6]<<16) + (Demod.output[5]<<8) + Demod.output[4], (Demod.output[3]<<24) + (Demod.output[2]<<16) + (Demod.output[1]<<8) + Demod.output[0]); // Now loop to read all 16 blocks, address from 0 to last block Dbprintf("Tag memory dump, block 0 to %d", numofblocks); cmd1[0] = 0x08; i = 0x00; ++numofblocks; for (;;) { if (i == numofblocks) { DbpString("System area block (0xff):"); i = 0xff; } cmd1[1] = i; ComputeCrc14443(CRC_14443_B, cmd1, 2, &cmd1[2], &cmd1[3]); CodeAndTransmit14443bAsReader(cmd1, sizeof(cmd1)); //no GetTagSamplesFor14443bDemod(); //no if (Demod.len != 6) { // Check if we got an answer from the tag DbpString("Expected 6 bytes from tag, got less..."); return; } // The check the CRC of the answer (use cmd1 as temporary variable): ComputeCrc14443(CRC_14443_B, Demod.output, 4, &cmd1[2], &cmd1[3]); if(cmd1[2] != Demod.output[4] || cmd1[3] != Demod.output[5]) { Dbprintf("CRC Error reading block! Expected: %04x got: %04x", (cmd1[2]<<8)+cmd1[3], (Demod.output[4]<<8)+Demod.output[5]); // Do not return;, let's go on... (we should retry, maybe ?) } // Now print out the memory location: Dbprintf("Address=%02x, Contents=%08x, CRC=%04x", i, (Demod.output[3]<<24) + (Demod.output[2]<<16) + (Demod.output[1]<<8) + Demod.output[0], (Demod.output[4]<<8)+Demod.output[5]); if (i == 0xff) break; ++i; } set_tracing(FALSE); } static void iso1444b_setup_snoop(void){ if (MF_DBGLEVEL > 3) Dbprintf("iso1443b_setup_snoop Enter"); LEDsoff(); FpgaDownloadAndGo(FPGA_BITSTREAM_HF); BigBuf_free(); BigBuf_Clear_ext(false); clear_trace();//setup snoop set_tracing(TRUE); // Initialize Demod and Uart structs DemodInit(BigBuf_malloc(MAX_FRAME_SIZE)); UartInit(BigBuf_malloc(MAX_FRAME_SIZE)); if (MF_DBGLEVEL > 1) { // Print debug information about the buffer sizes Dbprintf("Snooping buffers initialized:"); Dbprintf(" Trace: %i bytes", BigBuf_max_traceLen()); Dbprintf(" Reader -> tag: %i bytes", MAX_FRAME_SIZE); Dbprintf(" tag -> Reader: %i bytes", MAX_FRAME_SIZE); Dbprintf(" DMA: %i bytes", ISO14443B_DMA_BUFFER_SIZE); } // connect Demodulated Signal to ADC: SetAdcMuxFor(GPIO_MUXSEL_HIPKD); // Setup for the DMA. FpgaSetupSsc(); // Set FPGA in the appropriate mode FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_READER_RX_XCORR | FPGA_HF_READER_RX_XCORR_848_KHZ | FPGA_HF_READER_RX_XCORR_SNOOP); SpinDelay(20); // Start the SSP timer StartCountSspClk(); if (MF_DBGLEVEL > 3) Dbprintf("iso1443b_setup_snoop Exit"); } //============================================================================= // Finally, the `sniffer' combines elements from both the reader and // simulated tag, to show both sides of the conversation. //============================================================================= //----------------------------------------------------------------------------- // Record the sequence of commands sent by the reader to the tag, with // triggering so that we start recording at the point that the tag is moved // near the reader. //----------------------------------------------------------------------------- /* * Memory usage for this function, (within BigBuf) * Last Received command (reader->tag) - MAX_FRAME_SIZE * Last Received command (tag->reader) - MAX_FRAME_SIZE * DMA Buffer - ISO14443B_DMA_BUFFER_SIZE * Demodulated samples received - all the rest */ void RAMFUNC SnoopIso14443b(void) { uint32_t time_0 = 0, time_start = 0, time_stop = 0; // We won't start recording the frames that we acquire until we trigger; // a good trigger condition to get started is probably when we see a // response from the tag. int triggered = TRUE; // TODO: set and evaluate trigger condition int ci, cq; int maxBehindBy = 0; //int behindBy = 0; int lastRxCounter = ISO14443B_DMA_BUFFER_SIZE; bool TagIsActive = FALSE; bool ReaderIsActive = FALSE; iso1444b_setup_snoop(); // The DMA buffer, used to stream samples from the FPGA int8_t *dmaBuf = (int8_t*) BigBuf_malloc(ISO14443B_DMA_BUFFER_SIZE); int8_t *upTo = dmaBuf; // Setup and start DMA. if ( !FpgaSetupSscDma((uint8_t*) dmaBuf, ISO14443B_DMA_BUFFER_SIZE) ){ if (MF_DBGLEVEL > 1) Dbprintf("FpgaSetupSscDma failed. Exiting"); BigBuf_free(); return; } time_0 = GetCountSspClk(); // And now we loop, receiving samples. for(;;) { WDT_HIT(); int behindBy = (lastRxCounter - AT91C_BASE_PDC_SSC->PDC_RCR) & (ISO14443B_DMA_BUFFER_SIZE-1); if ( behindBy > maxBehindBy ) maxBehindBy = behindBy; if ( behindBy < 2 ) continue; ci = upTo[0]; cq = upTo[1]; upTo += 2; lastRxCounter -= 2; if (upTo >= dmaBuf + ISO14443B_DMA_BUFFER_SIZE) { upTo = dmaBuf; lastRxCounter += ISO14443B_DMA_BUFFER_SIZE; AT91C_BASE_PDC_SSC->PDC_RNPR = (uint32_t) dmaBuf; AT91C_BASE_PDC_SSC->PDC_RNCR = ISO14443B_DMA_BUFFER_SIZE; WDT_HIT(); // TODO: understand whether we can increase/decrease as we want or not? if ( behindBy > ( 9 * ISO14443B_DMA_BUFFER_SIZE/10) ) { Dbprintf("blew circular buffer! behindBy=%d", behindBy); break; } if(!tracing) { DbpString("Trace full"); break; } if(BUTTON_PRESS()) { DbpString("cancelled"); break; } } if (!TagIsActive) { LED_A_ON(); // no need to try decoding reader data if the tag is sending if (Handle14443bReaderUartBit(ci & 0x01)) { time_stop = (GetCountSspClk()-time_0); if (triggered) LogTrace(Uart.output, Uart.byteCnt, time_start, time_stop, NULL, TRUE); /* And ready to receive another command. */ UartReset(); /* And also reset the demod code, which might have been */ /* false-triggered by the commands from the reader. */ DemodReset(); } else { time_start = (GetCountSspClk()-time_0); } if (Handle14443bReaderUartBit(cq & 0x01)) { time_stop = (GetCountSspClk()-time_0); if (triggered) LogTrace(Uart.output, Uart.byteCnt, time_start, time_stop, NULL, TRUE); /* And ready to receive another command. */ UartReset(); /* And also reset the demod code, which might have been */ /* false-triggered by the commands from the reader. */ DemodReset(); } else { time_start = (GetCountSspClk()-time_0); } ReaderIsActive = (Uart.state > STATE_GOT_FALLING_EDGE_OF_SOF); LED_A_OFF(); } if(!ReaderIsActive) { // no need to try decoding tag data if the reader is sending - and we cannot afford the time // is this | 0x01 the error? & 0xfe in https://github.com/Proxmark/proxmark3/issues/103 if(Handle14443bTagSamplesDemod(ci & 0xFE, cq & 0xFE)) { time_stop = (GetCountSspClk()-time_0); LogTrace(Demod.output, Demod.len, time_start, time_stop, NULL, FALSE); triggered = TRUE; // And ready to receive another response. DemodReset(); } else { time_start = (GetCountSspClk()-time_0); } TagIsActive = (Demod.state > DEMOD_GOT_FALLING_EDGE_OF_SOF); } } switch_off(); // Snoop DbpString("Snoop statistics:"); Dbprintf(" Max behind by: %i", maxBehindBy); Dbprintf(" Uart State: %x ByteCount: %i ByteCountMax: %i", Uart.state, Uart.byteCnt, Uart.byteCntMax); Dbprintf(" Trace length: %i", BigBuf_get_traceLen()); // free mem refs. if ( dmaBuf ) dmaBuf = NULL; if ( upTo ) upTo = NULL; // Uart.byteCntMax should be set with ATQB value.. } void iso14b_set_trigger(bool enable) { trigger = enable; } /* * Send raw command to tag ISO14443B * @Input * param flags enum ISO14B_COMMAND. (mifare.h) * len len of buffer data * data buffer with bytes to send * * @Output * none * */ void SendRawCommand14443B_Ex(UsbCommand *c) { iso14b_command_t param = c->arg[0]; size_t len = c->arg[1] & 0xffff; uint8_t *cmd = c->d.asBytes; uint8_t status = 0; uint32_t sendlen = sizeof(iso14b_card_select_t); uint8_t buf[USB_CMD_DATA_SIZE] = {0x00}; if (MF_DBGLEVEL > 3) Dbprintf("14b raw: param, %04x", param ); // turn on trigger (LED_A) if ((param & ISO14B_REQUEST_TRIGGER) == ISO14B_REQUEST_TRIGGER) iso14b_set_trigger(TRUE); if ((param & ISO14B_CONNECT) == ISO14B_CONNECT) { // Make sure that we start from off, since the tags are stateful; // confusing things will happen if we don't reset them between reads. //switch_off(); // before connect in raw iso14443b_setup(); } set_tracing(TRUE); if ((param & ISO14B_SELECT_STD) == ISO14B_SELECT_STD) { iso14b_card_select_t *card = (iso14b_card_select_t*)buf; status = iso14443b_select_card(card); cmd_send(CMD_ACK, status, sendlen, 0, buf, sendlen); // 0: OK 2: attrib fail, 3:crc fail, if ( status > 0 ) return; } if ((param & ISO14B_SELECT_SR) == ISO14B_SELECT_SR) { iso14b_card_select_t *card = (iso14b_card_select_t*)buf; status = iso14443b_select_srx_card(card); cmd_send(CMD_ACK, status, sendlen, 0, buf, sendlen); // 0: OK 2: attrib fail, 3:crc fail, if ( status > 0 ) return; } if ((param & ISO14B_APDU) == ISO14B_APDU) { status = iso14443b_apdu(cmd, len, buf); cmd_send(CMD_ACK, status, status, 0, buf, status); } if ((param & ISO14B_RAW) == ISO14B_RAW) { if((param & ISO14B_APPEND_CRC) == ISO14B_APPEND_CRC) { AppendCrc14443b(cmd, len); len += 2; } CodeAndTransmit14443bAsReader(cmd, len); // raw GetTagSamplesFor14443bDemod(); // raw sendlen = MIN(Demod.len, USB_CMD_DATA_SIZE); status = (Demod.len > 0) ? 0 : 1; cmd_send(CMD_ACK, status, sendlen, 0, Demod.output, sendlen); } // turn off trigger (LED_A) if ((param & ISO14B_REQUEST_TRIGGER) == ISO14B_REQUEST_TRIGGER) iso14b_set_trigger(FALSE); // turn off antenna et al // we don't send a HALT command. if ((param & ISO14B_DISCONNECT) == ISO14B_DISCONNECT) { if (MF_DBGLEVEL > 3) Dbprintf("disconnect"); switch_off(); // disconnect raw } else { //FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_READER_TX | FPGA_HF_READER_TX_SHALLOW_MOD); } }