+
+#define abs(x) ( ((x)<0) ? -(x) : (x) )
+#define max(x,y) ( x<y ? y:x)
+
+int DemodPCF7931(uint8_t **outBlocks) {
+ uint8_t BitStream[256];
+ uint8_t Blocks[8][16];
+ uint8_t *GraphBuffer = (uint8_t *)BigBuf;
+ int GraphTraceLen = sizeof(BigBuf);
+ int i, j, lastval, bitidx, half_switch;
+ int clock = 64;
+ int tolerance = clock / 8;
+ int pmc, block_done;
+ int lc, warnings = 0;
+ int num_blocks = 0;
+ int lmin=128, lmax=128;
+ uint8_t dir;
+
+ AcquireRawAdcSamples125k(0);
+
+ lmin = 64;
+ lmax = 192;
+
+ i = 2;
+
+ /* Find first local max/min */
+ if(GraphBuffer[1] > GraphBuffer[0]) {
+ while(i < GraphTraceLen) {
+ if( !(GraphBuffer[i] > GraphBuffer[i-1]) && GraphBuffer[i] > lmax)
+ break;
+ i++;
+ }
+ dir = 0;
+ }
+ else {
+ while(i < GraphTraceLen) {
+ if( !(GraphBuffer[i] < GraphBuffer[i-1]) && GraphBuffer[i] < lmin)
+ break;
+ i++;
+ }
+ dir = 1;
+ }
+
+ lastval = i++;
+ half_switch = 0;
+ pmc = 0;
+ block_done = 0;
+
+ for (bitidx = 0; i < GraphTraceLen; i++)
+ {
+ if ( (GraphBuffer[i-1] > GraphBuffer[i] && dir == 1 && GraphBuffer[i] > lmax) || (GraphBuffer[i-1] < GraphBuffer[i] && dir == 0 && GraphBuffer[i] < lmin))
+ {
+ lc = i - lastval;
+ lastval = i;
+
+ // Switch depending on lc length:
+ // Tolerance is 1/8 of clock rate (arbitrary)
+ if (abs(lc-clock/4) < tolerance) {
+ // 16T0
+ if((i - pmc) == lc) { /* 16T0 was previous one */
+ /* It's a PMC ! */
+ i += (128+127+16+32+33+16)-1;
+ lastval = i;
+ pmc = 0;
+ block_done = 1;
+ }
+ else {
+ pmc = i;
+ }
+ } else if (abs(lc-clock/2) < tolerance) {
+ // 32TO
+ if((i - pmc) == lc) { /* 16T0 was previous one */
+ /* It's a PMC ! */
+ i += (128+127+16+32+33)-1;
+ lastval = i;
+ pmc = 0;
+ block_done = 1;
+ }
+ else if(half_switch == 1) {
+ BitStream[bitidx++] = 0;
+ half_switch = 0;
+ }
+ else
+ half_switch++;
+ } else if (abs(lc-clock) < tolerance) {
+ // 64TO
+ BitStream[bitidx++] = 1;
+ } else {
+ // Error
+ warnings++;
+ if (warnings > 10)
+ {
+ Dbprintf("Error: too many detection errors, aborting.");
+ return 0;
+ }
+ }
+
+ if(block_done == 1) {
+ if(bitidx == 128) {
+ for(j=0; j<16; j++) {
+ Blocks[num_blocks][j] = 128*BitStream[j*8+7]+
+ 64*BitStream[j*8+6]+
+ 32*BitStream[j*8+5]+
+ 16*BitStream[j*8+4]+
+ 8*BitStream[j*8+3]+
+ 4*BitStream[j*8+2]+
+ 2*BitStream[j*8+1]+
+ BitStream[j*8];
+ }
+ num_blocks++;
+ }
+ bitidx = 0;
+ block_done = 0;
+ half_switch = 0;
+ }
+ if (GraphBuffer[i-1] > GraphBuffer[i]) dir=0;
+ else dir = 1;
+ }
+ if(bitidx==255)
+ bitidx=0;
+ warnings = 0;
+ if(num_blocks == 4) break;
+ }
+ memcpy(outBlocks, Blocks, 16*num_blocks);
+ return num_blocks;
+}
+
+int IsBlock0PCF7931(uint8_t *Block) {
+ // Assume RFU means 0 :)
+ if((memcmp(Block, "\x00\x00\x00\x00\x00\x00\x00\x01", 8) == 0) && memcmp(Block+9, "\x00\x00\x00\x00\x00\x00\x00", 7) == 0) // PAC enabled
+ return 1;
+ if((memcmp(Block+9, "\x00\x00\x00\x00\x00\x00\x00", 7) == 0) && Block[7] == 0) // PAC disabled, can it *really* happen ?
+ return 1;
+ return 0;
+}
+
+int IsBlock1PCF7931(uint8_t *Block) {
+ // Assume RFU means 0 :)
+ if(Block[10] == 0 && Block[11] == 0 && Block[12] == 0 && Block[13] == 0)
+ if((Block[14] & 0x7f) <= 9 && Block[15] <= 9)
+ return 1;
+
+ return 0;
+}
+
+#define ALLOC 16
+
+void ReadPCF7931() {
+ uint8_t Blocks[8][17];
+ uint8_t tmpBlocks[4][16];
+ int i, j, ind, ind2, n;
+ int num_blocks = 0;
+ int max_blocks = 8;
+ int ident = 0;
+ int error = 0;
+ int tries = 0;
+
+ memset(Blocks, 0, 8*17*sizeof(uint8_t));
+
+ do {
+ memset(tmpBlocks, 0, 4*16*sizeof(uint8_t));
+ n = DemodPCF7931((uint8_t**)tmpBlocks);
+ if(!n)
+ error++;
+ if(error==10 && num_blocks == 0) {
+ Dbprintf("Error, no tag or bad tag");
+ return;
+ }
+ else if (tries==20 || error==10) {
+ Dbprintf("Error reading the tag");
+ Dbprintf("Here is the partial content");
+ goto end;
+ }
+
+ for(i=0; i<n; i++)
+ Dbprintf("(dbg) %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x",
+ tmpBlocks[i][0], tmpBlocks[i][1], tmpBlocks[i][2], tmpBlocks[i][3], tmpBlocks[i][4], tmpBlocks[i][5], tmpBlocks[i][6], tmpBlocks[i][7],
+ tmpBlocks[i][8], tmpBlocks[i][9], tmpBlocks[i][10], tmpBlocks[i][11], tmpBlocks[i][12], tmpBlocks[i][13], tmpBlocks[i][14], tmpBlocks[i][15]);
+ if(!ident) {
+ for(i=0; i<n; i++) {
+ if(IsBlock0PCF7931(tmpBlocks[i])) {
+ // Found block 0 ?
+ if(i < n-1 && IsBlock1PCF7931(tmpBlocks[i+1])) {
+ // Found block 1!
+ // \o/
+ ident = 1;
+ memcpy(Blocks[0], tmpBlocks[i], 16);
+ Blocks[0][ALLOC] = 1;
+ memcpy(Blocks[1], tmpBlocks[i+1], 16);
+ Blocks[1][ALLOC] = 1;
+ max_blocks = max((Blocks[1][14] & 0x7f), Blocks[1][15]) + 1;
+ // Debug print
+ Dbprintf("(dbg) Max blocks: %d", max_blocks);
+ num_blocks = 2;
+ // Handle following blocks
+ for(j=i+2, ind2=2; j!=i; j++, ind2++, num_blocks++) {
+ if(j==n) j=0;
+ if(j==i) break;
+ memcpy(Blocks[ind2], tmpBlocks[j], 16);
+ Blocks[ind2][ALLOC] = 1;
+ }
+ break;
+ }
+ }
+ }
+ }
+ else {
+ for(i=0; i<n; i++) { // Look for identical block in known blocks
+ if(memcmp(tmpBlocks[i], "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00", 16)) { // Block is not full of 00
+ for(j=0; j<max_blocks; j++) {
+ if(Blocks[j][ALLOC] == 1 && !memcmp(tmpBlocks[i], Blocks[j], 16)) {
+ // Found an identical block
+ for(ind=i-1,ind2=j-1; ind >= 0; ind--,ind2--) {
+ if(ind2 < 0)
+ ind2 = max_blocks;
+ if(!Blocks[ind2][ALLOC]) { // Block ind2 not already found
+ // Dbprintf("Tmp %d -> Block %d", ind, ind2);
+ memcpy(Blocks[ind2], tmpBlocks[ind], 16);
+ Blocks[ind2][ALLOC] = 1;
+ num_blocks++;
+ if(num_blocks == max_blocks) goto end;
+ }
+ }
+ for(ind=i+1,ind2=j+1; ind < n; ind++,ind2++) {
+ if(ind2 > max_blocks)
+ ind2 = 0;
+ if(!Blocks[ind2][ALLOC]) { // Block ind2 not already found
+ // Dbprintf("Tmp %d -> Block %d", ind, ind2);
+ memcpy(Blocks[ind2], tmpBlocks[ind], 16);
+ Blocks[ind2][ALLOC] = 1;
+ num_blocks++;
+ if(num_blocks == max_blocks) goto end;
+ }
+ }
+ }
+ }
+ }
+ }
+ }
+ tries++;
+ if (BUTTON_PRESS()) return;
+ } while (num_blocks != max_blocks);
+ end:
+ Dbprintf("-----------------------------------------");
+ Dbprintf("Memory content:");
+ Dbprintf("-----------------------------------------");
+ for(i=0; i<max_blocks; i++) {
+ if(Blocks[i][ALLOC]==1)
+ Dbprintf("%02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x",
+ Blocks[i][0], Blocks[i][1], Blocks[i][2], Blocks[i][3], Blocks[i][4], Blocks[i][5], Blocks[i][6], Blocks[i][7],
+ Blocks[i][8], Blocks[i][9], Blocks[i][10], Blocks[i][11], Blocks[i][12], Blocks[i][13], Blocks[i][14], Blocks[i][15]);
+ else
+ Dbprintf("<missing block %d>", i);
+ }
+ Dbprintf("-----------------------------------------");
+
+ return ;
+}
projects / proxmark3-svn / commitdiff