//----------------------------------------------------------------------------- // Routines to support ISO 14443. This includes both the reader software and // the `fake tag' modes. At the moment only the Type B modulation is // supported. // Jonathan Westhues, split Nov 2006 //----------------------------------------------------------------------------- #include #include "apps.h" #include "../common/iso14443_crc.c" //static void GetSamplesFor14443(BOOL weTx, int n); #define DMA_BUFFER_SIZE 256 //============================================================================= // 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. //============================================================================= //----------------------------------------------------------------------------- // 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 BYTE *cmd, int len) { int i; ToSendReset(); // Transmit a burst of ones, as the initial thing that lets the // reader get phase sync. This (TR1) must be > 80/fs, per spec, // but tag that I've tried (a Paypass) exceeds that by a fair bit, // so I will too. for(i = 0; i < 20; i++) { ToSendStuffBit(1); ToSendStuffBit(1); ToSendStuffBit(1); ToSendStuffBit(1); } // Send SOF. for(i = 0; i < 10; i++) { ToSendStuffBit(0); ToSendStuffBit(0); ToSendStuffBit(0); ToSendStuffBit(0); } for(i = 0; i < 2; i++) { ToSendStuffBit(1); ToSendStuffBit(1); ToSendStuffBit(1); ToSendStuffBit(1); } for(i = 0; i < len; i++) { int j; BYTE b = cmd[i]; // Start bit ToSendStuffBit(0); ToSendStuffBit(0); ToSendStuffBit(0); ToSendStuffBit(0); // Data bits for(j = 0; j < 8; j++) { if(b & 1) { ToSendStuffBit(1); ToSendStuffBit(1); ToSendStuffBit(1); ToSendStuffBit(1); } else { ToSendStuffBit(0); ToSendStuffBit(0); ToSendStuffBit(0); ToSendStuffBit(0); } b >>= 1; } // Stop bit ToSendStuffBit(1); ToSendStuffBit(1); ToSendStuffBit(1); ToSendStuffBit(1); } // Send SOF. for(i = 0; i < 10; i++) { ToSendStuffBit(0); ToSendStuffBit(0); ToSendStuffBit(0); ToSendStuffBit(0); } for(i = 0; i < 10; i++) { ToSendStuffBit(1); ToSendStuffBit(1); ToSendStuffBit(1); ToSendStuffBit(1); } // Convert from last byte pos to length ToSendMax++; // Add a few more for slop ToSendMax += 2; } //----------------------------------------------------------------------------- // 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_ERROR_WAIT } state; WORD shiftReg; int bitCnt; int byteCnt; int byteCntMax; int posCnt; BYTE *output; } Uart; /* Receive & handle a bit coming from the reader. * * 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 BOOL Handle14443UartBit(int bit) { switch(Uart.state) { case STATE_UNSYNCD: LED_A_OFF(); 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) { if(bit) { if(Uart.bitCnt >= 10) { // 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_ERROR_WAIT; } } else { // do nothing, keep waiting } Uart.bitCnt++; } if(Uart.posCnt >= 4) Uart.posCnt = 0; if(Uart.bitCnt > 14) { // Give up if we see too many zeros without // a one, too. Uart.state = STATE_ERROR_WAIT; } break; case STATE_AWAITING_START_BIT: Uart.posCnt++; if(bit) { if(Uart.posCnt > 25) { // stayed high for too long between // characters, error Uart.state = STATE_ERROR_WAIT; } } else { // falling edge, this starts the data byte Uart.posCnt = 0; Uart.bitCnt = 0; Uart.shiftReg = 0; Uart.state = STATE_RECEIVING_DATA; LED_A_ON(); // Indicate we're receiving } 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 Uart.posCnt = 0; Uart.state = STATE_ERROR_WAIT; } 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 return TRUE; } else { // this is an error Uart.posCnt = 0; Uart.state = STATE_ERROR_WAIT; } } break; case STATE_ERROR_WAIT: // We're all screwed up, so wait a little while // for whatever went wrong to finish, and then // start over. Uart.posCnt++; if(Uart.posCnt > 10) { Uart.state = STATE_UNSYNCD; } break; default: Uart.state = STATE_UNSYNCD; break; } if (Uart.state == STATE_ERROR_WAIT) LED_A_OFF(); // Error 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 BOOL GetIso14443CommandFromReader(BYTE *received, int *len, int maxLen) { BYTE mask; int i, bit; // Set FPGA mode to "simulated ISO 14443 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); // Now run a `software UART' on the stream of incoming samples. Uart.output = received; Uart.byteCntMax = maxLen; Uart.state = STATE_UNSYNCD; for(;;) { WDT_HIT(); if(BUTTON_PRESS()) return FALSE; if(SSC_STATUS & (SSC_STATUS_TX_READY)) { SSC_TRANSMIT_HOLDING = 0x00; } if(SSC_STATUS & (SSC_STATUS_RX_READY)) { BYTE b = (BYTE)SSC_RECEIVE_HOLDING; mask = 0x80; for(i = 0; i < 8; i++, mask >>= 1) { bit = (b & mask); if(Handle14443UartBit(bit)) { *len = Uart.byteCnt; return TRUE; } } } } } //----------------------------------------------------------------------------- // Main loop of simulated tag: receive commands from reader, decide what // response to send, and send it. //----------------------------------------------------------------------------- void SimulateIso14443Tag(void) { static const BYTE cmd1[] = { 0x05, 0x00, 0x08, 0x39, 0x73 }; static const BYTE response1[] = { 0x50, 0x82, 0x0d, 0xe1, 0x74, 0x20, 0x38, 0x19, 0x22, 0x00, 0x21, 0x85, 0x5e, 0xd7 }; BYTE *resp; int respLen; BYTE *resp1 = (((BYTE *)BigBuf) + 800); int resp1Len; BYTE *receivedCmd = (BYTE *)BigBuf; int len; int i; int cmdsRecvd = 0; memset(receivedCmd, 0x44, 400); CodeIso14443bAsTag(response1, sizeof(response1)); memcpy(resp1, ToSend, ToSendMax); resp1Len = ToSendMax; // We need to listen to the high-frequency, peak-detected path. SetAdcMuxFor(GPIO_MUXSEL_HIPKD); FpgaSetupSsc(); cmdsRecvd = 0; for(;;) { BYTE b1, b2; if(!GetIso14443CommandFromReader(receivedCmd, &len, 100)) { DbpIntegers(cmdsRecvd, 0, 0); DbpString("button press"); break; } // Good, look at the command now. if(len == sizeof(cmd1) && memcmp(receivedCmd, cmd1, len)==0) { resp = resp1; respLen = resp1Len; } else { DbpString("new cmd from reader:"); DbpIntegers(len, 0x1234, cmdsRecvd); // And print whether the CRC fails, just for good measure ComputeCrc14443(CRC_14443_B, receivedCmd, len-2, &b1, &b2); if(b1 != receivedCmd[len-2] || b2 != receivedCmd[len-1]) { // Not so good, try again. DbpString("+++CRC fail"); } else { DbpString("CRC passes"); } break; } memset(receivedCmd, 0x44, 32); cmdsRecvd++; if(cmdsRecvd > 0x30) { DbpString("many commands later..."); break; } if(respLen <= 0) continue; // Modulate BPSK // Signal field is off with the appropriate LED LED_D_OFF(); FpgaWriteConfWord( FPGA_MAJOR_MODE_HF_SIMULATOR | FPGA_HF_SIMULATOR_MODULATE_BPSK); SSC_TRANSMIT_HOLDING = 0xff; FpgaSetupSsc(); // Transmit the response. i = 0; for(;;) { if(SSC_STATUS & (SSC_STATUS_TX_READY)) { BYTE b = resp[i]; SSC_TRANSMIT_HOLDING = b; i++; if(i > respLen) { break; } } if(SSC_STATUS & (SSC_STATUS_RX_READY)) { volatile BYTE b = (BYTE)SSC_RECEIVE_HOLDING; (void)b; } } } } //============================================================================= // 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. //============================================================================= 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, DEMOD_ERROR_WAIT } state; int bitCount; int posCount; int thisBit; int metric; int metricN; WORD shiftReg; BYTE *output; int len; int sumI; int sumQ; } Demod; /* * Handles reception of a bit from the tag * * 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 BOOL Handle14443SamplesDemod(int ci, int cq) { int v; // 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; \ } \ } switch(Demod.state) { case DEMOD_UNSYNCD: v = ci; if(v < 0) v = -v; if(cq > 0) { v += cq; } else { v -= cq; } if(v > 40) { Demod.posCount = 0; Demod.state = DEMOD_PHASE_REF_TRAINING; Demod.sumI = 0; Demod.sumQ = 0; } break; case DEMOD_PHASE_REF_TRAINING: if(Demod.posCount < 8) { Demod.sumI += ci; Demod.sumQ += cq; } else if(Demod.posCount > 100) { // error, waited too long Demod.state = DEMOD_UNSYNCD; } else { MAKE_SOFT_DECISION(); if(v < 0) { Demod.state = DEMOD_AWAITING_FALLING_EDGE_OF_SOF; Demod.posCount = 0; } } Demod.posCount++; break; case DEMOD_AWAITING_FALLING_EDGE_OF_SOF: MAKE_SOFT_DECISION(); if(v < 0) { Demod.state = DEMOD_GOT_FALLING_EDGE_OF_SOF; Demod.posCount = 0; } else { if(Demod.posCount > 100) { Demod.state = DEMOD_UNSYNCD; } } Demod.posCount++; break; case DEMOD_GOT_FALLING_EDGE_OF_SOF: MAKE_SOFT_DECISION(); if(v > 0) { if(Demod.posCount < 12) { Demod.state = DEMOD_UNSYNCD; } else { LED_C_ON(); // Got SOF Demod.state = DEMOD_AWAITING_START_BIT; Demod.posCount = 0; Demod.len = 0; Demod.metricN = 0; Demod.metric = 0; } } else { if(Demod.posCount > 100) { Demod.state = DEMOD_UNSYNCD; } } Demod.posCount++; break; case DEMOD_AWAITING_START_BIT: MAKE_SOFT_DECISION(); if(v > 0) { if(Demod.posCount > 10) { Demod.state = DEMOD_UNSYNCD; } } else { Demod.bitCount = 0; Demod.posCount = 1; Demod.thisBit = v; Demod.shiftReg = 0; Demod.state = DEMOD_RECEIVING_DATA; } break; case DEMOD_RECEIVING_DATA: MAKE_SOFT_DECISION(); if(Demod.posCount == 0) { Demod.thisBit = v; Demod.posCount = 1; } else { Demod.thisBit += v; if(Demod.thisBit > 0) { Demod.metric += Demod.thisBit; } else { Demod.metric -= Demod.thisBit; } (Demod.metricN)++; Demod.shiftReg >>= 1; if(Demod.thisBit > 0) { Demod.shiftReg |= 0x200; } Demod.bitCount++; if(Demod.bitCount == 10) { WORD s = Demod.shiftReg; if((s & 0x200) && !(s & 0x001)) { BYTE b = (s >> 1); Demod.output[Demod.len] = b; Demod.len++; Demod.state = DEMOD_AWAITING_START_BIT; } else if(s == 0x000) { // This is EOF LED_C_OFF(); return TRUE; Demod.state = DEMOD_UNSYNCD; } else { Demod.state = DEMOD_UNSYNCD; } } Demod.posCount = 0; } break; default: Demod.state = DEMOD_UNSYNCD; break; } if (Demod.state == DEMOD_UNSYNCD) LED_C_OFF(); // Not synchronized... return FALSE; } /* * Demodulate the samples we received from the tag * weTx: set to 'TRUE' if we behave like a reader * set to 'FALSE' if we behave like a snooper * quiet: set to 'TRUE' to disable debug output */ static void GetSamplesFor14443Demod(BOOL weTx, int n, BOOL quiet) { int max = 0; BOOL gotFrame = FALSE; //# define DMA_BUFFER_SIZE 8 SBYTE *dmaBuf; int lastRxCounter; SBYTE *upTo; int ci, cq; int samples = 0; // Clear out the state of the "UART" that receives from the tag. memset(BigBuf, 0x44, 400); Demod.output = (BYTE *)BigBuf; Demod.len = 0; Demod.state = DEMOD_UNSYNCD; // And the UART that receives from the reader Uart.output = (((BYTE *)BigBuf) + 1024); Uart.byteCntMax = 100; Uart.state = STATE_UNSYNCD; // Setup for the DMA. dmaBuf = (SBYTE *)(BigBuf + 32); upTo = dmaBuf; lastRxCounter = DMA_BUFFER_SIZE; FpgaSetupSscDma((BYTE *)dmaBuf, DMA_BUFFER_SIZE); // Signal field is ON with the appropriate LED: if (weTx) LED_D_ON(); else LED_D_OFF(); // And put the FPGA in the appropriate mode FpgaWriteConfWord( FPGA_MAJOR_MODE_HF_READER_RX_XCORR | FPGA_HF_READER_RX_XCORR_848_KHZ | (weTx ? 0 : FPGA_HF_READER_RX_XCORR_SNOOP)); for(;;) { int behindBy = lastRxCounter - PDC_RX_COUNTER(SSC_BASE); if(behindBy > max) max = behindBy; while(((lastRxCounter-PDC_RX_COUNTER(SSC_BASE)) & (DMA_BUFFER_SIZE-1)) > 2) { ci = upTo[0]; cq = upTo[1]; upTo += 2; if(upTo - dmaBuf > DMA_BUFFER_SIZE) { upTo -= DMA_BUFFER_SIZE; PDC_RX_NEXT_POINTER(SSC_BASE) = (DWORD)upTo; PDC_RX_NEXT_COUNTER(SSC_BASE) = DMA_BUFFER_SIZE; } lastRxCounter -= 2; if(lastRxCounter <= 0) { lastRxCounter += DMA_BUFFER_SIZE; } samples += 2; Handle14443UartBit(1); Handle14443UartBit(1); if(Handle14443SamplesDemod(ci, cq)) { gotFrame = 1; } } if(samples > 2000) { break; } } PDC_CONTROL(SSC_BASE) = PDC_RX_DISABLE; if (!quiet) DbpIntegers(max, gotFrame, Demod.len); } //----------------------------------------------------------------------------- // Read the tag's response. We just receive a stream of slightly-processed // samples from the FPGA, which we will later do some signal processing on, // to get the bits. //----------------------------------------------------------------------------- /*static void GetSamplesFor14443(BOOL weTx, int n) { BYTE *dest = (BYTE *)BigBuf; int c; FpgaWriteConfWord( FPGA_MAJOR_MODE_HF_READER_RX_XCORR | FPGA_HF_READER_RX_XCORR_848_KHZ | (weTx ? 0 : FPGA_HF_READER_RX_XCORR_SNOOP)); c = 0; for(;;) { if(SSC_STATUS & (SSC_STATUS_TX_READY)) { SSC_TRANSMIT_HOLDING = 0x43; } if(SSC_STATUS & (SSC_STATUS_RX_READY)) { SBYTE b; b = (SBYTE)SSC_RECEIVE_HOLDING; dest[c++] = (BYTE)b; if(c >= n) { break; } } } }*/ //----------------------------------------------------------------------------- // Transmit the command (to the tag) that was placed in ToSend[]. //----------------------------------------------------------------------------- static void TransmitFor14443(void) { int c; FpgaSetupSsc(); while(SSC_STATUS & (SSC_STATUS_TX_READY)) { SSC_TRANSMIT_HOLDING = 0xff; } // Signal field is ON with the appropriate Red LED LED_D_ON(); // Signal we are transmitting with the Green LED LED_B_ON(); FpgaWriteConfWord( FPGA_MAJOR_MODE_HF_READER_TX | FPGA_HF_READER_TX_SHALLOW_MOD); for(c = 0; c < 10;) { if(SSC_STATUS & (SSC_STATUS_TX_READY)) { SSC_TRANSMIT_HOLDING = 0xff; c++; } if(SSC_STATUS & (SSC_STATUS_RX_READY)) { volatile DWORD r = SSC_RECEIVE_HOLDING; (void)r; } WDT_HIT(); } c = 0; for(;;) { if(SSC_STATUS & (SSC_STATUS_TX_READY)) { SSC_TRANSMIT_HOLDING = ToSend[c]; c++; if(c >= ToSendMax) { break; } } if(SSC_STATUS & (SSC_STATUS_RX_READY)) { volatile DWORD r = SSC_RECEIVE_HOLDING; (void)r; } WDT_HIT(); } LED_B_OFF(); // Finished sending } //----------------------------------------------------------------------------- // Code a layer 2 command (string of octets, including CRC) into ToSend[], // so that it is ready to transmit to the tag using TransmitFor14443(). //----------------------------------------------------------------------------- void CodeIso14443bAsReader(const BYTE *cmd, int len) { int i, j; BYTE b; ToSendReset(); // Establish initial reference level for(i = 0; i < 40; i++) { ToSendStuffBit(1); } // Send SOF for(i = 0; i < 10; i++) { ToSendStuffBit(0); } for(i = 0; i < len; i++) { // Stop bits/EGT ToSendStuffBit(1); ToSendStuffBit(1); // Start bit ToSendStuffBit(0); // Data bits b = cmd[i]; for(j = 0; j < 8; j++) { if(b & 1) { ToSendStuffBit(1); } else { ToSendStuffBit(0); } b >>= 1; } } // Send EOF ToSendStuffBit(1); for(i = 0; i < 10; i++) { ToSendStuffBit(0); } for(i = 0; i < 8; i++) { ToSendStuffBit(1); } // And then a little more, to make sure that the last character makes // it out before we switch to rx mode. for(i = 0; i < 24; i++) { ToSendStuffBit(1); } // Convert from last character reference to length ToSendMax++; } //----------------------------------------------------------------------------- // Read an ISO 14443 tag. We send it some set of commands, and record the // responses. // The command name is misleading, it actually decodes the reponse in HEX // into the output buffer (read the result using hexsamples, not hisamples) //----------------------------------------------------------------------------- void AcquireRawAdcSamplesIso14443(DWORD parameter) { BYTE cmd1[] = { 0x05, 0x00, 0x08, 0x39, 0x73 }; // Make sure that we start from off, since the tags are stateful; // confusing things will happen if we don't reset them between reads. FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF); LED_D_OFF(); SpinDelay(200); 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(200); CodeIso14443bAsReader(cmd1, sizeof(cmd1)); TransmitFor14443(); // LED_A_ON(); GetSamplesFor14443Demod(TRUE, 2000, FALSE); // LED_A_OFF(); } //----------------------------------------------------------------------------- // Read a SRI512 ISO 14443 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 ReadSRI512Iso14443(DWORD parameter) { BYTE i = 0x00; // Make sure that we start from off, since the tags are stateful; // confusing things will happen if we don't reset them between reads. LED_D_OFF(); FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF); SpinDelay(200); 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(200); // First command: wake up the tag using the INITIATE command BYTE cmd1[] = { 0x06, 0x00, 0x97, 0x5b}; CodeIso14443bAsReader(cmd1, sizeof(cmd1)); TransmitFor14443(); // LED_A_ON(); GetSamplesFor14443Demod(TRUE, 2000,TRUE); // LED_A_OFF(); if (Demod.len == 0) { DbpString("No response from tag"); return; } else { DbpString("Randomly generated UID from tag (+ 2 byte CRC):"); DbpIntegers(Demod.output[0], Demod.output[1],Demod.output[2]); } // There is a response, SELECT the uid DbpString("Now SELECT tag:"); cmd1[0] = 0x0E; // 0x0E is SELECT cmd1[1] = Demod.output[0]; ComputeCrc14443(CRC_14443_B, cmd1, 2, &cmd1[2], &cmd1[3]); CodeIso14443bAsReader(cmd1, sizeof(cmd1)); TransmitFor14443(); // LED_A_ON(); GetSamplesFor14443Demod(TRUE, 2000,TRUE); // LED_A_OFF(); if (Demod.len != 3) { DbpString("Expected 3 bytes from tag, got:"); DbpIntegers(Demod.len,0x0,0x0); 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."); return; } // Check response from the tag: should be the same UID as the command we just sent: if (cmd1[1] != Demod.output[0]) { DbpString("Bad response to SELECT from Tag, aborting:"); DbpIntegers(cmd1[1],Demod.output[0],0x0); return; } // Tag is now selected, // First get the tag's UID: cmd1[0] = 0x0B; ComputeCrc14443(CRC_14443_B, cmd1, 1 , &cmd1[1], &cmd1[2]); CodeIso14443bAsReader(cmd1, 3); // Only first three bytes for this one TransmitFor14443(); // LED_A_ON(); GetSamplesFor14443Demod(TRUE, 2000,TRUE); // LED_A_OFF(); if (Demod.len != 10) { DbpString("Expected 10 bytes from tag, got:"); DbpIntegers(Demod.len,0x0,0x0); 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]) { DbpString("CRC Error reading block! - Below: expected, got"); DbpIntegers( (cmd1[2]<<8)+cmd1[3], (Demod.output[8]<<8)+Demod.output[9],0); // Do not return;, let's go on... (we should retry, maybe ?) } DbpString("Tag UID (64 bits):"); DbpIntegers((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], 0); // Now loop to read all 16 blocks, address from 0 to 15 DbpString("Tag memory dump, block 0 to 15"); cmd1[0] = 0x08; i = 0x00; for (;;) { if (i == 0x10) { DbpString("System area block (0xff):"); i = 0xff; } cmd1[1] = i; ComputeCrc14443(CRC_14443_B, cmd1, 2, &cmd1[2], &cmd1[3]); CodeIso14443bAsReader(cmd1, sizeof(cmd1)); TransmitFor14443(); // LED_A_ON(); GetSamplesFor14443Demod(TRUE, 2000,TRUE); // LED_A_OFF(); 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]) { DbpString("CRC Error reading block! - Below: expected, got"); DbpIntegers( (cmd1[2]<<8)+cmd1[3], (Demod.output[4]<<8)+Demod.output[5],0); // Do not return;, let's go on... (we should retry, maybe ?) } // Now print out the memory location: DbpString("Address , Contents, CRC"); DbpIntegers(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++; } } //============================================================================= // 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) * 0-1023 : Demodulated samples receive (1024 bytes) * 1024-1535 : Last Received command, 512 bytes (reader->tag) * 1536-2047 : Last Received command, 512 bytes(tag->reader) * 2048-2304 : DMA Buffer, 256 bytes (samples) */ void SnoopIso14443(void) { // 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 triggered = FALSE; // The command (reader -> tag) that we're working on receiving. BYTE *receivedCmd = (BYTE *)(BigBuf) + 1024; // The response (tag -> reader) that we're working on receiving. BYTE *receivedResponse = (BYTE *)(BigBuf) + 1536; // As we receive stuff, we copy it from receivedCmd or receivedResponse // into trace, along with its length and other annotations. BYTE *trace = (BYTE *)BigBuf; int traceLen = 0; // The DMA buffer, used to stream samples from the FPGA. SBYTE *dmaBuf = (SBYTE *)(BigBuf) + 2048; int lastRxCounter; SBYTE *upTo; int ci, cq; int maxBehindBy = 0; // Count of samples received so far, so that we can include timing // information in the trace buffer. int samples = 0; // Initialize the trace buffer memset(trace, 0x44, 1024); // Set up the demodulator for tag -> reader responses. Demod.output = receivedResponse; Demod.len = 0; Demod.state = DEMOD_UNSYNCD; // And the reader -> tag commands memset(&Uart, 0, sizeof(Uart)); Uart.output = receivedCmd; Uart.byteCntMax = 100; Uart.state = STATE_UNSYNCD; // And put the FPGA in the appropriate mode // Signal field is off with the appropriate LED LED_D_OFF(); FpgaWriteConfWord( FPGA_MAJOR_MODE_HF_READER_RX_XCORR | FPGA_HF_READER_RX_XCORR_848_KHZ | FPGA_HF_READER_RX_XCORR_SNOOP); SetAdcMuxFor(GPIO_MUXSEL_HIPKD); // Setup for the DMA. FpgaSetupSsc(); upTo = dmaBuf; lastRxCounter = DMA_BUFFER_SIZE; FpgaSetupSscDma((BYTE *)dmaBuf, DMA_BUFFER_SIZE); // And now we loop, receiving samples. for(;;) { int behindBy = (lastRxCounter - PDC_RX_COUNTER(SSC_BASE)) & (DMA_BUFFER_SIZE-1); if(behindBy > maxBehindBy) { maxBehindBy = behindBy; if(behindBy > (DMA_BUFFER_SIZE-2)) { // TODO: understand whether we can increase/decrease as we want or not? DbpString("blew circular buffer!"); DbpIntegers(behindBy,0,0); goto done; } } if(behindBy < 2) continue; ci = upTo[0]; cq = upTo[1]; upTo += 2; lastRxCounter -= 2; if(upTo - dmaBuf > DMA_BUFFER_SIZE) { upTo -= DMA_BUFFER_SIZE; lastRxCounter += DMA_BUFFER_SIZE; PDC_RX_NEXT_POINTER(SSC_BASE) = (DWORD) upTo; PDC_RX_NEXT_COUNTER(SSC_BASE) = DMA_BUFFER_SIZE; } samples += 2; #define HANDLE_BIT_IF_BODY \ if(triggered) { \ trace[traceLen++] = ((samples >> 0) & 0xff); \ trace[traceLen++] = ((samples >> 8) & 0xff); \ trace[traceLen++] = ((samples >> 16) & 0xff); \ trace[traceLen++] = ((samples >> 24) & 0xff); \ trace[traceLen++] = 0; \ trace[traceLen++] = 0; \ trace[traceLen++] = 0; \ trace[traceLen++] = 0; \ trace[traceLen++] = Uart.byteCnt; \ memcpy(trace+traceLen, receivedCmd, Uart.byteCnt); \ traceLen += Uart.byteCnt; \ if(traceLen > 1000) break; \ } \ /* And ready to receive another command. */ \ memset(&Uart, 0, sizeof(Uart)); \ Uart.output = receivedCmd; \ Uart.byteCntMax = 100; \ Uart.state = STATE_UNSYNCD; \ /* And also reset the demod code, which might have been */ \ /* false-triggered by the commands from the reader. */ \ memset(&Demod, 0, sizeof(Demod)); \ Demod.output = receivedResponse; \ Demod.state = DEMOD_UNSYNCD; \ if(Handle14443UartBit(ci & 1)) { HANDLE_BIT_IF_BODY } if(Handle14443UartBit(cq & 1)) { HANDLE_BIT_IF_BODY } if(Handle14443SamplesDemod(ci, cq)) { // timestamp, as a count of samples trace[traceLen++] = ((samples >> 0) & 0xff); trace[traceLen++] = ((samples >> 8) & 0xff); trace[traceLen++] = ((samples >> 16) & 0xff); trace[traceLen++] = 0x80 | ((samples >> 24) & 0xff); // correlation metric (~signal strength estimate) if(Demod.metricN != 0) { Demod.metric /= Demod.metricN; } trace[traceLen++] = ((Demod.metric >> 0) & 0xff); trace[traceLen++] = ((Demod.metric >> 8) & 0xff); trace[traceLen++] = ((Demod.metric >> 16) & 0xff); trace[traceLen++] = ((Demod.metric >> 24) & 0xff); // length trace[traceLen++] = Demod.len; memcpy(trace+traceLen, receivedResponse, Demod.len); traceLen += Demod.len; if(traceLen > 1000) break; triggered = TRUE; // And ready to receive another response. memset(&Demod, 0, sizeof(Demod)); Demod.output = receivedResponse; Demod.state = DEMOD_UNSYNCD; } WDT_HIT(); if(BUTTON_PRESS()) { DbpString("cancelled"); goto done; } } DbpString("in done pt"); DbpIntegers(maxBehindBy, Uart.state, Uart.byteCnt); DbpIntegers(Uart.byteCntMax, traceLen, 0x23); done: LED_D_OFF(); PDC_CONTROL(SSC_BASE) = PDC_RX_DISABLE; }