//----------------------------------------------------------------------------- // 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" #include "proxmark3_arm.h" #include "common.h" // access to global variable: DBGLEVEL #include "util.h" #include "string.h" #include "crc16.h" #include "protocols.h" #include "appmain.h" #include "BigBuf.h" #include "cmd.h" #include "fpgaloader.h" #include "commonutil.h" #include "dbprint.h" #include "ticks.h" #ifndef FWT_TIMEOUT_14B // defaults to 2000ms # define FWT_TIMEOUT_14B 35312 #endif #ifndef ISO14443B_DMA_BUFFER_SIZE # define ISO14443B_DMA_BUFFER_SIZE 512 //changed this from 256 #endif #ifndef RECEIVE_MASK # define RECEIVE_MASK (ISO14443B_DMA_BUFFER_SIZE-1) #endif // Guard Time (per 14443-2) #ifndef TR0 # define TR0 32 //this value equals 8 ETU = 32 ssp clk (w/ 424 khz) #endif // Synchronization time (per 14443-2) #ifndef TR1 # define TR1 0 #endif // Frame Delay Time PICC to PCD (per 14443-3 Amendment 1) #ifndef TR2 # define TR2 0 #endif // 4sample #define SEND4STUFFBIT(x) ToSendStuffBit(x);ToSendStuffBit(x);ToSendStuffBit(x);ToSendStuffBit(x); //#define SEND4STUFFBIT(x) ToSendStuffBit(x); // iceman, this threshold value, what makes 8 a good amplitude for this IQ values? #ifndef SUBCARRIER_DETECT_THRESHOLD # define SUBCARRIER_DETECT_THRESHOLD 8 #endif static void iso14b_set_timeout(uint32_t timeout); static void iso14b_set_maxframesize(uint16_t size); // the block number for the ISO14443-4 PCB (used with APDUs) static uint8_t pcb_blocknum = 0; static uint32_t iso14b_timeout = FWT_TIMEOUT_14B; //============================================================================= // An ISO 14443 Type B tag. We listen for commands from the reader, using // a 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 that receives commands from the reader, and its state variables. //----------------------------------------------------------------------------- static struct { enum { STATE_14B_UNSYNCD, STATE_14B_GOT_FALLING_EDGE_OF_SOF, STATE_14B_AWAITING_START_BIT, STATE_14B_RECEIVING_DATA } state; uint16_t shiftReg; int bitCnt; int byteCnt; int byteCntMax; int posCnt; uint8_t *output; } Uart; static void Uart14bReset(void) { Uart.state = STATE_14B_UNSYNCD; Uart.shiftReg = 0; Uart.bitCnt = 0; Uart.byteCnt = 0; Uart.byteCntMax = MAX_FRAME_SIZE; Uart.posCnt = 0; } static void Uart14bInit(uint8_t *data) { Uart.output = data; Uart14bReset(); // 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 Demod14bReset(void) { 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 Demod14bInit(uint8_t *data) { Demod.output = data; Demod14bReset(); // memset(Demod.output, 0x00, MAX_FRAME_SIZE); } /* * 9.4395 us = 1 ETU and clock is about 1.5 us * 13560000Hz * 1000ms/s * timeout in ETUs (time to transfer 1 bit, 9.4395 us) * * Formula to calculate FWT (in ETUs) by timeout (in ms): * fwt = 13560000 * 1000 / (8*16) * timeout; * Sample: 3sec == 3000ms * 13560000 * 1000 / (8*16) * 3000 == * 13560000000 / 384000 = 35312 FWT * @param timeout is in frame wait time, fwt, measured in ETUs */ static void iso14b_set_timeout(uint32_t timeout) { #define MAX_TIMEOUT 40542464 // 13560000Hz * 1000ms / (2^32-1) * (8*16) if (timeout > MAX_TIMEOUT) timeout = MAX_TIMEOUT; iso14b_timeout = timeout; if (DBGLEVEL >= 3) Dbprintf("ISO14443B Timeout set to %ld fwt", iso14b_timeout); } static void iso14b_set_maxframesize(uint16_t size) { if (size > 256) size = MAX_FRAME_SIZE; Uart.byteCntMax = size; if (DBGLEVEL >= 3) Dbprintf("ISO14443B Max frame size set to %d bytes", Uart.byteCntMax); } //----------------------------------------------------------------------------- // 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 13.56 MHz * 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 (1.18µS / pulse) == 9.44us * - A 0-bit input to the FPGA becomes an unmodulated time of 1.18µS or does it become 8 nonpulses for 9.44us * * FPGA doesn't seem to work with ETU. It seems to work with pulse / duration instead. * * Card sends data ub 847.e kHz subcarrier * subcar |duration| FC division * -------+--------+------------ * 106kHz | 9.44µS | FC/128 * 212kHz | 4.72µS | FC/64 * 424kHz | 2.36µS | FC/32 * 848kHz | 1.18µS | FC/16 * -------+--------+------------ * * 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) * */ 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 TR1. // 10-11 ETU * 4times samples ONES for (int i = 0; i < 10; i++) { SEND4STUFFBIT(1); } // Send SOF. // 10-11 ETU * 4times samples ZEROS for (int i = 0; i < 10; i++) { SEND4STUFFBIT(0); } //for(i = 0; i < 10; i++) { ToSendStuffBit(0); } // 2-3 ETU * 4times samples ONES for (int i = 0; i < 3; i++) { SEND4STUFFBIT(1); } //for(i = 0; i < 3; i++) { ToSendStuffBit(1); } // data for (int i = 0; i < len; ++i) { // Start bit SEND4STUFFBIT(0); //ToSendStuffBit(0); // Data bits uint8_t b = cmd[i]; for (int j = 0; j < 8; ++j) { // if(b & 1) { // SEND4STUFFBIT(1); // //ToSendStuffBit(1); // } else { // SEND4STUFFBIT(0); // //ToSendStuffBit(0); // } SEND4STUFFBIT(b & 1); b >>= 1; } // Stop bit SEND4STUFFBIT(1); //ToSendStuffBit(1); // Extra Guard bit // For PICC it ranges 0-18us (1etu = 9us) SEND4STUFFBIT(1); //ToSendStuffBit(1); } // Send EOF. // 10-11 ETU * 4 sample rate = ZEROS for (int i = 0; i < 10; i++) { SEND4STUFFBIT(0); } //for(i = 0; i < 10; i++) { ToSendStuffBit(0); } // why this? for (int i = 0; i < 2; i++) { SEND4STUFFBIT(1); } //for(i = 0; i < 40; i++) { ToSendStuffBit(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_14B_UNSYNCD: if (!bit) { // we went low, so this could be the beginning of an SOF Uart.state = STATE_14B_GOT_FALLING_EDGE_OF_SOF; Uart.posCnt = 0; Uart.bitCnt = 0; } break; case STATE_14B_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_14B_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_14B_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_14B_UNSYNCD; } break; case STATE_14B_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_14B_UNSYNCD; } } else { // falling edge, this starts the data byte Uart.posCnt = 0; Uart.bitCnt = 0; Uart.shiftReg = 0; Uart.state = STATE_14B_RECEIVING_DATA; } break; case STATE_14B_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_14B_UNSYNCD; } else { // so get the next byte now Uart.posCnt = 0; Uart.state = STATE_14B_AWAITING_START_BIT; } } else if (Uart.shiftReg == 0x000) { // this is an EOF byte LED_A_OFF(); // Finished receiving Uart.state = STATE_14B_UNSYNCD; if (Uart.byteCnt != 0) return true; } else { // this is an error LED_A_OFF(); Uart.state = STATE_14B_UNSYNCD; } } break; default: LED_A_OFF(); Uart.state = STATE_14B_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? // loop is a wait/delay ? /* for(uint8_t c = 0; c < 10;) { // keep tx buffer in a defined state anyway. 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. Uart14bInit(received); uint8_t mask; while (!BUTTON_PRESS()) { WDT_HIT(); // keep tx buffer in a defined state anyway. if (AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) { AT91C_BASE_SSC->SSC_THR = 0x00; } // Wait for byte be become available in rx holding register 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) { volatile uint32_t b; // 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); SpinDelay(40); ClearFpgaShiftingRegisters(); FpgaSetupSsc(); // Transmit the response. for (uint16_t i = 0; i < len;) { // Put byte into tx holding register as soon as it is ready if (AT91C_BASE_SSC->SSC_SR & AT91C_SSC_TXRDY) { AT91C_BASE_SSC->SSC_THR = response[++i]; } // Prevent rx holding register from overflowing if (AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_RXRDY)) { b = AT91C_BASE_SSC->SSC_RHR; (void)b; } } //WaitForFpgaDelayQueueIsEmpty(fpgasendQueueDelay); AT91C_BASE_SSC->SSC_THR = 0xFF; } //----------------------------------------------------------------------------- // 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); // connect Demodulated Signal to ADC: SetAdcMuxFor(GPIO_MUXSEL_HIPKD); // Set up the synchronous serial port FpgaSetupSsc(); // allocate command receive buffer BigBuf_free(); BigBuf_Clear_ext(false); clear_trace(); //sim set_tracing(true); 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); AddCrc14B(respATQB, 12); } // 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() && !data_available()) { WDT_HIT(); // find reader field if (cardSTATE == SIM_NOFIELD) { #if defined RDV4 vHf = (MAX_ADC_HF_VOLTAGE_RDV40 * SumAdc(ADC_CHAN_HF_RDV40, 32)) >> 15; #else vHf = (MAX_ADC_HF_VOLTAGE * SumAdc(ADC_CHAN_HF, 32)) >> 15; #endif 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 if (len >= 3) { // if crc exists if (!check_crc(CRC_14443_B, receivedCmd, len)) DbpString("+++CRC fail"); else DbpString("CRC passes"); } cardSTATE = SIM_IDLE; } break; } default: break; } ++cmdsReceived; } if (DBGLEVEL >= 2) Dbprintf("Emulator stopped. Trace length: %d ", 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 * */ static RAMFUNC int Handle14443bTagSamplesDemod(int ci, int cq) { int v = 0, myI = ABS(ci), myQ = ABS(cq); // 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(void) { \ 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_old(void) { \ 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(void) { 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 > 200 / 4) 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.state = DEMOD_AWAITING_START_BIT; Demod.posCount = 0; Demod.len = 0; } } else { // low phase of SOF too long (> 12 etu) if (Demod.posCount > 14 * 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 > 6 * 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; // OR in a logic '1' if (Demod.thisBit > 0) Demod.shiftReg |= 0x200; Demod.bitCount++; // 1 start 8 data 1 stop = 10 if (Demod.bitCount == 10) { uint16_t s = Demod.shiftReg; // stop bit == '1', start bit == '0' if ((s & 0x200) && (s & 0x001) == 0) { // left shift to drop the startbit uint8_t b = (s >> 1); Demod.output[Demod.len] = b; ++Demod.len; Demod.state = DEMOD_AWAITING_START_BIT; } else { // this one is a bit hard, either its a correc byte or its unsynced. Demod.state = DEMOD_UNSYNCD; 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(void) { bool finished = false; // int lastRxCounter = ISO14443B_DMA_BUFFER_SIZE; uint32_t time_0 = 0, time_stop = 0; BigBuf_free(); // Set up the demodulator for tag -> reader responses. Demod14bInit(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 (DBGLEVEL > 1) Dbprintf("FpgaSetupSscDma failed. Exiting"); return; } // And put the FPGA in the appropriate mode FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_READER_RX_XCORR | FPGA_HF_READER_RX_XCORR_848_KHZ); // get current clock time_0 = GetCountSspClk(); // rx counter - dma counter? (how much?) & (mod) mask > 2. (since 2bytes at the time is read) while (!finished) { LED_A_INV(); WDT_HIT(); // LSB is a fpga signal bit. int ci = upTo[0]; int cq = upTo[1]; upTo += 2; // lastRxCounter -= 2; // restart DMA buffer to receive again. if (upTo >= dmaBuf + ISO14443B_DMA_BUFFER_SIZE) { upTo = dmaBuf; // lastRxCounter = ISO14443B_DMA_BUFFER_SIZE; AT91C_BASE_PDC_SSC->PDC_RNPR = (uint32_t) upTo; AT91C_BASE_PDC_SSC->PDC_RNCR = ISO14443B_DMA_BUFFER_SIZE; } // https://github.com/Proxmark/proxmark3/issues/103 bool gotFrame = Handle14443bTagSamplesDemod(ci, cq); time_stop = GetCountSspClk() - time_0; finished = (time_stop > iso14b_timeout || gotFrame); } FpgaDisableSscDma(); if (upTo) upTo = NULL; if (Demod.len > 0) LogTrace(Demod.output, Demod.len, time_0, time_stop, NULL, false); } //----------------------------------------------------------------------------- // Transmit the command (to the tag) that was placed in ToSend[]. //----------------------------------------------------------------------------- static void TransmitFor14443b_AsReader(void) { int c; FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_READER_TX | FPGA_HF_READER_TX_SHALLOW_MOD); SpinDelay(60); // What does this loop do? Is it TR1? // 0xFF = 8 bits of 1. 1 bit == 1Etu,.. // loop 10 * 8 = 80 ETU of delay, with a non modulated signal. why? // 80*9 = 720us. for (c = 0; c < 50;) { if (AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) { AT91C_BASE_SSC->SSC_THR = 0xFF; c++; } } // Send frame loop for (c = 0; c < ToSendMax;) { // Put byte into tx holding register as soon as it is ready if (AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) { AT91C_BASE_SSC->SSC_THR = ToSend[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. * * QUESTION: how long is a 1 or 0 in pulses in the xcorr_848 mode? * 1 "stuffbit" = 1ETU (9us) */ ToSendReset(); // Send SOF // 10-11 ETUs of ZERO for (int 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 (int i = 0; i < len; ++i) { // Start bit ToSendStuffBit(0); // Data bits uint8_t 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); ToSendStuffBit(b & 1); ToSendStuffBit((b >> 1) & 1); ToSendStuffBit((b >> 2) & 1); ToSendStuffBit((b >> 3) & 1); ToSendStuffBit((b >> 4) & 1); ToSendStuffBit((b >> 5) & 1); ToSendStuffBit((b >> 6) & 1); ToSendStuffBit((b >> 7) & 1); // 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 (int 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. // I'm guessing this is for the FPGA to be able to send all bits before we switch to listening mode for (int i = 0; i < 24 ; ++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) { uint32_t time_start = GetCountSspClk(); CodeIso14443bAsReader(cmd, len); TransmitFor14443b_AsReader(); if (g_trigger) LED_A_ON(); LogTrace(cmd, len, time_start, GetCountSspClk(), 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 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) AddCrc14B(message_frame, message_length + 2); // send CodeAndTransmit14443bAsReader(message_frame, message_length + 4); //no // get response GetTagSamplesFor14443bDemod(); //no FpgaDisableTracing(); if (Demod.len < 3) return 0; // VALIDATE CRC if (!check_crc(CRC_14443_B, Demod.output, Demod.len)) { if (DBGLEVEL > 3) Dbprintf("crc fail ICE"); return 0; } // copy response contents if (response != NULL) memcpy(response, Demod.output, Demod.len); return Demod.len; } /** * SRx Initialise. */ static 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}; CodeAndTransmit14443bAsReader(init_srx, sizeof(init_srx)); GetTagSamplesFor14443bDemod(); //no FpgaDisableTracing(); if (Demod.len == 0) return 2; // Randomly generated Chip ID if (card) card->chipid = Demod.output[0]; select_srx[1] = Demod.output[0]; AddCrc14B(select_srx, 2); CodeAndTransmit14443bAsReader(select_srx, sizeof(select_srx)); GetTagSamplesFor14443bDemod(); //no FpgaDisableTracing(); if (Demod.len != 3) return 2; // Check the CRC of the answer: if (!check_crc(CRC_14443_B, Demod.output, Demod.len)) 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; AddCrc14B(select_srx, 1); CodeAndTransmit14443bAsReader(select_srx, 3); // Only first three bytes for this one GetTagSamplesFor14443bDemod(); //no FpgaDisableTracing(); if (Demod.len != 10) return 2; // The check the CRC of the answer if (!check_crc(CRC_14443_B, Demod.output, Demod.len)) 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}; // first, wake up the tag CodeAndTransmit14443bAsReader(wupb, sizeof(wupb)); GetTagSamplesFor14443bDemod(); //select_card FpgaDisableTracing(); // ATQB too short? if (Demod.len < 14) return 2; // VALIDATE CRC if (!check_crc(CRC_14443_B, Demod.output, Demod.len)) 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; AddCrc14B(attrib, 9); CodeAndTransmit14443bAsReader(attrib, sizeof(attrib)); GetTagSamplesFor14443bDemod();//select_card FpgaDisableTracing(); // Answer to ATTRIB too short? if (Demod.len < 3) return 2; // VALIDATE CRC if (!check_crc(CRC_14443_B, Demod.output, Demod.len)) return 3; if (card) { // CID card->cid = Demod.output[0]; // MAX FRAME uint16_t maxFrame = card->atqb[5] >> 4; if (maxFrame < 5) maxFrame = 8 * maxFrame + 16; else if (maxFrame == 5) maxFrame = 64; else if (maxFrame == 6) maxFrame = 96; else if (maxFrame == 7) maxFrame = 128; else if (maxFrame == 8) maxFrame = 256; else maxFrame = 257; iso14b_set_maxframesize(maxFrame); // FWT 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(void) { LEDsoff(); FpgaDownloadAndGo(FPGA_BITSTREAM_HF); // Initialize Demod and Uart structs Demod14bInit(BigBuf_malloc(MAX_FRAME_SIZE)); Uart14bInit(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(); } //----------------------------------------------------------------------------- // 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... //----------------------------------------------------------------------------- static bool ReadSTBlock(uint8_t block) { uint8_t cmd[] = {ISO14443B_READ_BLK, block, 0x00, 0x00}; AddCrc14B(cmd, 2); CodeAndTransmit14443bAsReader(cmd, sizeof(cmd)); GetTagSamplesFor14443bDemod(); FpgaDisableTracing(); // Check if we got an answer from the tag if (Demod.len != 6) { DbpString("[!] expected 6 bytes from tag, got less..."); return false; } // The check the CRC of the answer if (!check_crc(CRC_14443_B, Demod.output, Demod.len)) { DbpString("[!] CRC Error block!"); return false; } return true; } void ReadSTMemoryIso14443b(uint8_t numofblocks) { // 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(); uint8_t i = 0x00; uint8_t *buf = BigBuf_malloc(sizeof(iso14b_card_select_t)); iso14443b_setup(); iso14b_card_select_t *card = (iso14b_card_select_t *)buf; uint8_t res = iso14443b_select_srx_card(card); // 0: OK 2: attrib fail, 3:crc fail, if (res > 0) goto out; Dbprintf("[+] Tag memory dump, block 0 to %d", numofblocks); ++numofblocks; for (;;) { if (i == numofblocks) { DbpString("System area block (0xFF):"); i = 0xff; } uint8_t retries = 3; do { res = ReadSTBlock(i); } while (!res && --retries); if (!res && !retries) { goto out; } // 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; } out: switch_off(); // disconnect raw SpinDelay(20); } static void iso1444b_setup_sniff(void) { LEDsoff(); FpgaDownloadAndGo(FPGA_BITSTREAM_HF); BigBuf_free(); BigBuf_Clear_ext(false); clear_trace(); set_tracing(true); // Initialize Demod and Uart structs Demod14bInit(BigBuf_malloc(MAX_FRAME_SIZE)); Uart14bInit(BigBuf_malloc(MAX_FRAME_SIZE)); if (DBGLEVEL > 1) { // Print debug information about the buffer sizes Dbprintf("[+] Sniff 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(); } //============================================================================= // 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 SniffIso14443b(void) { uint32_t time_0 = 0, time_start = 0, time_stop; // 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. bool TagIsActive = false; bool ReaderIsActive = false; iso1444b_setup_sniff(); // The DMA buffer, used to stream samples from the FPGA int8_t *dmaBuf = (int8_t *) BigBuf_malloc(ISO14443B_DMA_BUFFER_SIZE); int8_t *data = dmaBuf; // Setup and start DMA. if (!FpgaSetupSscDma((uint8_t *) dmaBuf, ISO14443B_DMA_BUFFER_SIZE)) { if (DBGLEVEL > 1) Dbprintf("[!] FpgaSetupSscDma failed. Exiting"); BigBuf_free(); return; } // time ZERO, the point from which it all is calculated. time_0 = GetCountSspClk(); // loop and listen while (!BUTTON_PRESS()) { WDT_HIT(); int ci = data[0]; int cq = data[1]; data += 2; if (data >= dmaBuf + ISO14443B_DMA_BUFFER_SIZE) { data = dmaBuf; AT91C_BASE_PDC_SSC->PDC_RNPR = (uint32_t) dmaBuf; AT91C_BASE_PDC_SSC->PDC_RNCR = ISO14443B_DMA_BUFFER_SIZE; } // no need to try decoding reader data if the tag is sending if (!TagIsActive) { LED_A_INV(); if (Handle14443bReaderUartBit(ci & 0x01)) { time_stop = GetCountSspClk() - time_0; LogTrace(Uart.output, Uart.byteCnt, time_start, time_stop, NULL, true); Uart14bReset(); Demod14bReset(); } else { time_start = GetCountSspClk() - time_0; } if (Handle14443bReaderUartBit(cq & 0x01)) { time_stop = GetCountSspClk() - time_0; LogTrace(Uart.output, Uart.byteCnt, time_start, time_stop, NULL, true); Uart14bReset(); Demod14bReset(); } else { time_start = GetCountSspClk() - time_0; } ReaderIsActive = (Uart.state > STATE_14B_GOT_FALLING_EDGE_OF_SOF); } // no need to try decoding tag data if the reader is sending - and we cannot afford the time if (!ReaderIsActive) { // is this | 0x01 the error? & 0xfe in https://github.com/Proxmark/proxmark3/issues/103 // LSB is a fpga signal bit. if (Handle14443bTagSamplesDemod(ci, cq)) { time_stop = GetCountSspClk() - time_0; LogTrace(Demod.output, Demod.len, time_start, time_stop, NULL, false); Uart14bReset(); Demod14bReset(); } else { time_start = GetCountSspClk() - time_0; } TagIsActive = (Demod.state > DEMOD_GOT_FALLING_EDGE_OF_SOF); } } if (DBGLEVEL >= 2) { DbpString("[+] Sniff statistics:"); Dbprintf("[+] uart State: %x ByteCount: %i ByteCountMax: %i", Uart.state, Uart.byteCnt, Uart.byteCntMax); Dbprintf("[+] trace length: %i", BigBuf_get_traceLen()); } switch_off(); } static void iso14b_set_trigger(bool enable) { g_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(PacketCommandNG *c) { iso14b_command_t param = c->oldarg[0]; size_t len = c->oldarg[1] & 0xffff; uint32_t timeout = c->oldarg[2]; uint8_t *cmd = c->data.asBytes; uint8_t status; uint32_t sendlen = sizeof(iso14b_card_select_t); uint8_t buf[PM3_CMD_DATA_SIZE] = {0x00}; if (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) { iso14443b_setup(); clear_trace(); } if ((param & ISO14B_SET_TIMEOUT)) iso14b_set_timeout(timeout); 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); reply_mix(CMD_ACK, status, sendlen, 0, buf, sendlen); // 0: OK 2: attrib fail, 3:crc fail, if (status > 0) goto out; } if ((param & ISO14B_SELECT_SR) == ISO14B_SELECT_SR) { iso14b_card_select_t *card = (iso14b_card_select_t *)buf; status = iso14443b_select_srx_card(card); reply_mix(CMD_ACK, status, sendlen, 0, buf, sendlen); // 0: OK 2: demod fail, 3:crc fail, if (status > 0) goto out; } if ((param & ISO14B_APDU) == ISO14B_APDU) { status = iso14443b_apdu(cmd, len, buf); reply_mix(CMD_ACK, status, status, 0, buf, status); } if ((param & ISO14B_RAW) == ISO14B_RAW) { if ((param & ISO14B_APPEND_CRC) == ISO14B_APPEND_CRC) { AddCrc14B(cmd, len); len += 2; } CodeAndTransmit14443bAsReader(cmd, len); // raw GetTagSamplesFor14443bDemod(); // raw FpgaDisableTracing(); sendlen = MIN(Demod.len, PM3_CMD_DATA_SIZE); status = (Demod.len > 0) ? 0 : 1; reply_old(CMD_ACK, status, sendlen, 0, Demod.output, sendlen); } out: // 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) { switch_off(); // disconnect raw SpinDelay(20); } }