+
+//-----------------------------------------------------------------------------
+// MIFARE sniffer.
+//
+//-----------------------------------------------------------------------------
+void RAMFUNC SniffMifare(void) {
+ LEDsoff();
+ // init trace buffer
+ traceLen = 0;
+ memset(trace, 0x44, TRACE_SIZE);
+
+ // 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 = FALSE; // FALSE to wait first for card
+
+ // The command (reader -> tag) that we're receiving.
+ // The length of a received command will in most cases be no more than 18 bytes.
+ // So 32 should be enough!
+ uint8_t *receivedCmd = (((uint8_t *)BigBuf) + RECV_CMD_OFFSET);
+ // The response (tag -> reader) that we're receiving.
+ uint8_t *receivedResponse = (((uint8_t *)BigBuf) + RECV_RES_OFFSET);
+
+ // As we receive stuff, we copy it from receivedCmd or receivedResponse
+ // into trace, along with its length and other annotations.
+ //uint8_t *trace = (uint8_t *)BigBuf;
+
+ // The DMA buffer, used to stream samples from the FPGA
+ int8_t *dmaBuf = ((int8_t *)BigBuf) + DMA_BUFFER_OFFSET;
+ int lastRxCounter;
+ int8_t *upTo;
+ int smpl;
+ int maxBehindBy = 0;
+
+ // Set up the demodulator for tag -> reader responses.
+ Demod.output = receivedResponse;
+ Demod.len = 0;
+ Demod.state = DEMOD_UNSYNCD;
+
+ // Set up the demodulator for the reader -> tag commands
+ memset(&Uart, 0, sizeof(Uart));
+ Uart.output = receivedCmd;
+ Uart.byteCntMax = 32; // was 100 (greg)//////////////////
+ Uart.state = STATE_UNSYNCD;
+
+ // Setup for the DMA.
+ FpgaSetupSsc();
+ upTo = dmaBuf;
+ lastRxCounter = DMA_BUFFER_SIZE;
+ FpgaSetupSscDma((uint8_t *)dmaBuf, DMA_BUFFER_SIZE);
+
+ // And put the FPGA in the appropriate mode
+ // Signal field is off with the appropriate LED
+ LED_D_OFF();
+ FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_ISO14443A | FPGA_HF_ISO14443A_SNIFFER);
+ SetAdcMuxFor(GPIO_MUXSEL_HIPKD);
+
+ // Count of samples received so far, so that we can include timing
+ // information in the trace buffer.
+ rsamples = 0;
+ // And now we loop, receiving samples.
+ while(true) {
+ LED_A_ON();
+ WDT_HIT();
+ int behindBy = (lastRxCounter - AT91C_BASE_PDC_SSC->PDC_RCR) &
+ (DMA_BUFFER_SIZE-1);
+ if(behindBy > maxBehindBy) {
+ maxBehindBy = behindBy;
+ if(behindBy > 400) {
+ Dbprintf("blew circular buffer! behindBy=0x%x", behindBy);
+ goto done;
+ }
+ }
+ if(behindBy < 1) continue;
+
+ LED_A_OFF();
+
+ smpl = upTo[0];
+ upTo++;
+ lastRxCounter -= 1;
+ if(upTo - dmaBuf > DMA_BUFFER_SIZE) {
+ upTo -= DMA_BUFFER_SIZE;
+ lastRxCounter += DMA_BUFFER_SIZE;
+ AT91C_BASE_PDC_SSC->PDC_RNPR = (uint32_t) upTo;
+ AT91C_BASE_PDC_SSC->PDC_RNCR = DMA_BUFFER_SIZE;
+ }
+
+ rsamples += 4;
+ if(MillerDecoding((smpl & 0xF0) >> 4)) {
+ LED_C_ON();
+ if(triggered) {
+ if (!LogTrace(receivedCmd, Uart.byteCnt, -1 * Uart.samples, Uart.parityBits, TRUE)) break;
+ }
+ /* And ready to receive another command. */
+ Uart.state = STATE_UNSYNCD;
+ /* And also reset the demod code, which might have been */
+ /* false-triggered by the commands from the reader. */
+ Demod.state = DEMOD_UNSYNCD;
+ LED_B_OFF();
+ }
+
+ if(ManchesterDecoding(smpl & 0x0F)) {
+ LED_B_ON();
+
+ if (!LogTrace(receivedResponse, Demod.len, -1 * Demod.samples, Demod.parityBits, FALSE)) break;
+
+ triggered = TRUE;
+
+ // And ready to receive another response.
+ memset(&Demod, 0, sizeof(Demod));
+ Demod.output = receivedResponse;
+ Demod.state = DEMOD_UNSYNCD;
+ LED_C_OFF();
+ }
+
+ if(BUTTON_PRESS()) {
+ DbpString("button cancelled");
+ goto done;
+ }
+ } // main cycle
+
+ DbpString("COMMAND FINISHED");
+
+done:
+ AT91C_BASE_PDC_SSC->PDC_PTCR = AT91C_PDC_RXTDIS;
+ Dbprintf("maxBehindBy=%x, Uart.state=%x, Uart.byteCnt=%x", maxBehindBy, Uart.state, Uart.byteCnt);
+ Dbprintf("Uart.byteCntMax=%x, traceLen=%x, Uart.output[0]=%x", Uart.byteCntMax, traceLen, (int)Uart.output[0]);
+ LEDsoff();
+}
\ No newline at end of file
projects / proxmark3-svn / commitdiff