Experimeting with finding the "WDT_HIT" bug in "Hf mf mifare", which not shows if...

diff --git a/armsrc/iso14443a.c b/armsrc/iso14443a.c
index 1c4d0f05f35129c994deb0c178d1161ca887b4a3..8dbe9e81f714fb21c4cff3d43ca43086bfc0ce27 100644 (file)
--- a/armsrc/iso14443a.c
+++ b/armsrc/iso14443a.c
@@ -106,8 +106,6 @@ static uint32_t NextTransferTime;
 static uint32_t LastTimeProxToAirStart;
 static uint32_t LastProxToAirDuration;
 
 static uint32_t LastTimeProxToAirStart;
 static uint32_t LastProxToAirDuration;
 

-
-

 // CARD TO READER - manchester
 // Sequence D: 11110000 modulation with subcarrier during first half
 // Sequence E: 00001111 modulation with subcarrier during second half
 // CARD TO READER - manchester
 // Sequence D: 11110000 modulation with subcarrier during first half
 // Sequence E: 00001111 modulation with subcarrier during second half


@@ -127,13 +125,11 @@ void iso14a_set_trigger(bool enable) {
        trigger = enable;
 }
 
        trigger = enable;
 }
 

-

 void iso14a_set_timeout(uint32_t timeout) {
        iso14a_timeout = timeout;
        if(MF_DBGLEVEL >= 3) Dbprintf("ISO14443A Timeout set to %ld (%dms)", iso14a_timeout, iso14a_timeout / 106);
 }
 
 void iso14a_set_timeout(uint32_t timeout) {
        iso14a_timeout = timeout;
        if(MF_DBGLEVEL >= 3) Dbprintf("ISO14443A Timeout set to %ld (%dms)", iso14a_timeout, iso14a_timeout / 106);
 }
 

-

 void iso14a_set_ATS_timeout(uint8_t *ats) {
 
        uint8_t tb1;
 void iso14a_set_ATS_timeout(uint8_t *ats) {
 
        uint8_t tb1;


@@ -142,20 +138,22 @@ void iso14a_set_ATS_timeout(uint8_t *ats) {
        
        if (ats[0] > 1) {                                                       // there is a format byte T0
                if ((ats[1] & 0x20) == 0x20) {                  // there is an interface byte TB(1)
        
        if (ats[0] > 1) {                                                       // there is a format byte T0
                if ((ats[1] & 0x20) == 0x20) {                  // there is an interface byte TB(1)

-                       if ((ats[1] & 0x10) == 0x10) {          // there is an interface byte TA(1) preceding TB(1)
+
+                       if ((ats[1] & 0x10) == 0x10)            // there is an interface byte TA(1) preceding TB(1)

                                tb1 = ats[3];
                                tb1 = ats[3];

-                       } else {
+                       else

                                tb1 = ats[2];
                                tb1 = ats[2];

-                       }
+

                        fwi = (tb1 & 0xf0) >> 4;                        // frame waiting indicator (FWI)
                        fwi = (tb1 & 0xf0) >> 4;                        // frame waiting indicator (FWI)

-                       fwt = 256 * 16 * (1 << fwi);            // frame waiting time (FWT) in 1/fc
+                       //fwt = 256 * 16 * (1 << fwi);          // frame waiting time (FWT) in 1/fc
+                       fwt = 4096 * (1 << fwi);

                        
                        

-                       iso14a_set_timeout(fwt/(8*16));
+                       //iso14a_set_timeout(fwt/(8*16));
+                       iso14a_set_timeout(fwt/128);

                }
        }
 }
 
                }
        }
 }
 

-

 //-----------------------------------------------------------------------------
 // Generate the parity value for a byte sequence
 //
 //-----------------------------------------------------------------------------
 // Generate the parity value for a byte sequence
 //


@@ -1059,10 +1057,12 @@ void SimulateIso14443aTag(int tagType, int flags, byte_t* data)
                { .response = response3a, .response_n = sizeof(response3a) },  // Acknowledge select - cascade 2
                { .response = response5,  .response_n = sizeof(response5)  },  // Authentication answer (random nonce)
                { .response = response6,  .response_n = sizeof(response6)  },  // dummy ATS (pseudo-ATR), answer to RATS
                { .response = response3a, .response_n = sizeof(response3a) },  // Acknowledge select - cascade 2
                { .response = response5,  .response_n = sizeof(response5)  },  // Authentication answer (random nonce)
                { .response = response6,  .response_n = sizeof(response6)  },  // dummy ATS (pseudo-ATR), answer to RATS

-               //{ .response = response7_NTAG, .response_n = sizeof(response7_NTAG)}, // EV1/NTAG GET_VERSION response
+

                { .response = response8,   .response_n = sizeof(response8) }  // EV1/NTAG PACK response
                { .response = response8,   .response_n = sizeof(response8) }  // EV1/NTAG PACK response

+       };      
+               //{ .response = response7_NTAG, .response_n = sizeof(response7_NTAG)}, // EV1/NTAG GET_VERSION response

                //{ .response = response9,      .response_n = sizeof(response9)     }  // EV1/NTAG CHK_TEAR response
                //{ .response = response9,      .response_n = sizeof(response9)     }  // EV1/NTAG CHK_TEAR response

-       };
+       

 
        // Allocate 512 bytes for the dynamic modulation, created when the reader queries for it
        // Such a response is less time critical, so we can prepare them on the fly
 
        // Allocate 512 bytes for the dynamic modulation, created when the reader queries for it
        // Such a response is less time critical, so we can prepare them on the fly


@@ -1112,6 +1112,9 @@ void SimulateIso14443aTag(int tagType, int flags, byte_t* data)
 
        LED_A_ON();
        for(;;) {
 
        LED_A_ON();
        for(;;) {

+               
+               WDT_HIT();
+               

                // Clean receive command buffer
                if(!GetIso14443aCommandFromReader(receivedCmd, receivedCmdPar, &len)) {
                        DbpString("Button press");
                // Clean receive command buffer
                if(!GetIso14443aCommandFromReader(receivedCmd, receivedCmdPar, &len)) {
                        DbpString("Button press");


@@ -1434,7 +1437,7 @@ void PrepareDelayedTransfer(uint16_t delay)
                for (uint16_t i = 0; i < delay; i++) {
                        bitmask |= (0x01 << i);
                }
                for (uint16_t i = 0; i < delay; i++) {
                        bitmask |= (0x01 << i);
                }

-               ToSend[ToSendMax++] = 0x00;
+               ToSend[++ToSendMax] = 0x00;

                for (uint16_t i = 0; i < ToSendMax; i++) {
                        bits_to_shift = ToSend[i] & bitmask;
                        ToSend[i] = ToSend[i] >> delay;
                for (uint16_t i = 0; i < ToSendMax; i++) {
                        bits_to_shift = ToSend[i] & bitmask;
                        ToSend[i] = ToSend[i] >> delay;


@@ -1466,6 +1469,7 @@ static void TransmitFor14443a(const uint8_t *cmd, uint16_t len, uint32_t *timing
                        PrepareDelayedTransfer(*timing & 0x00000007);           // Delay transfer (fine tuning - up to 7 MF clock ticks)
                }
                if(MF_DBGLEVEL >= 4 && GetCountSspClk() >= (*timing & 0xfffffff8)) Dbprintf("TransmitFor14443a: Missed timing");
                        PrepareDelayedTransfer(*timing & 0x00000007);           // Delay transfer (fine tuning - up to 7 MF clock ticks)
                }
                if(MF_DBGLEVEL >= 4 && GetCountSspClk() >= (*timing & 0xfffffff8)) Dbprintf("TransmitFor14443a: Missed timing");

+               

                while(GetCountSspClk() < (*timing & 0xfffffff8));               // Delay transfer (multiple of 8 MF clock ticks)
                LastTimeProxToAirStart = *timing;
        } else {
                while(GetCountSspClk() < (*timing & 0xfffffff8));               // Delay transfer (multiple of 8 MF clock ticks)
                LastTimeProxToAirStart = *timing;
        } else {


@@ -1481,7 +1485,7 @@ static void TransmitFor14443a(const uint8_t *cmd, uint16_t len, uint32_t *timing
        for(;;) {
                if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) {
                        AT91C_BASE_SSC->SSC_THR = cmd[c];
        for(;;) {
                if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) {
                        AT91C_BASE_SSC->SSC_THR = cmd[c];

-                       c++;
+                       ++c;

                        if(c >= len)
                                break;
                }
                        if(c >= len)
                                break;
                }


@@ -1886,10 +1890,10 @@ int iso14443a_select_card(byte_t *uid_ptr, iso14a_card_select_t *p_hi14a_card, u
        uint8_t sel_all[]    = { 0x93,0x20 };
        uint8_t sel_uid[]    = { 0x93,0x70,0x00,0x00,0x00,0x00,0x00,0x00,0x00};
        uint8_t rats[]       = { 0xE0,0x80,0x00,0x00 }; // FSD=256, FSDI=8, CID=0
        uint8_t sel_all[]    = { 0x93,0x20 };
        uint8_t sel_uid[]    = { 0x93,0x70,0x00,0x00,0x00,0x00,0x00,0x00,0x00};
        uint8_t rats[]       = { 0xE0,0x80,0x00,0x00 }; // FSD=256, FSDI=8, CID=0

-       uint8_t resp[MAX_FRAME_SIZE]; // theoretically. A usual RATS will be much smaller
-       uint8_t resp_par[MAX_PARITY_SIZE];
-       byte_t uid_resp[4];
-       size_t uid_resp_len;
+       uint8_t resp[MAX_FRAME_SIZE] = {0}; // theoretically. A usual RATS will be much smaller
+       uint8_t resp_par[MAX_PARITY_SIZE] = {0};
+       byte_t uid_resp[4] = {0};
+       size_t uid_resp_len = 0;

 
        uint8_t sak = 0x04; // cascade uid
        int cascade_level = 0;
 
        uint8_t sak = 0x04; // cascade uid
        int cascade_level = 0;


@@ -1908,16 +1912,13 @@ int iso14443a_select_card(byte_t *uid_ptr, iso14a_card_select_t *p_hi14a_card, u
        }
 
        if (anticollision) {
        }
 
        if (anticollision) {

-       // clear uid
-       if (uid_ptr) {
-               memset(uid_ptr,0,10);
-       }
+               // clear uid
+               if (uid_ptr)
+                       memset(uid_ptr,0,10);

        }
 
        // check for proprietary anticollision:
        }
 
        // check for proprietary anticollision:

-       if ((resp[0] & 0x1F) == 0) {
-               return 3;
-       }
+       if ((resp[0] & 0x1F) == 0) return 3;

        
        // OK we will select at least at cascade 1, lets see if first byte of UID was 0x88 in
        // which case we need to make a cascade 2 request and select - this is a long UID
        
        // OK we will select at least at cascade 1, lets see if first byte of UID was 0x88 in
        // which case we need to make a cascade 2 request and select - this is a long UID


@@ -1928,40 +1929,41 @@ int iso14443a_select_card(byte_t *uid_ptr, iso14a_card_select_t *p_hi14a_card, u
 
                if (anticollision) {
                // SELECT_ALL
 
                if (anticollision) {
                // SELECT_ALL

-               ReaderTransmit(sel_all, sizeof(sel_all), NULL);
-               if (!ReaderReceive(resp, resp_par)) return 0;
-
-               if (Demod.collisionPos) {                       // we had a collision and need to construct the UID bit by bit
-                       memset(uid_resp, 0, 4);
-                       uint16_t uid_resp_bits = 0;
-                       uint16_t collision_answer_offset = 0;
-                       // anti-collision-loop:
-                       while (Demod.collisionPos) {
-                               Dbprintf("Multiple tags detected. Collision after Bit %d", Demod.collisionPos);
-                               for (uint16_t i = collision_answer_offset; i < Demod.collisionPos; i++, uid_resp_bits++) {      // add valid UID bits before collision point
-                                       uint16_t UIDbit = (resp[i/8] >> (i % 8)) & 0x01;
-                                       uid_resp[uid_resp_bits / 8] |= UIDbit << (uid_resp_bits % 8);
+                       ReaderTransmit(sel_all, sizeof(sel_all), NULL);
+                       if (!ReaderReceive(resp, resp_par)) return 0;
+
+                       if (Demod.collisionPos) {                       // we had a collision and need to construct the UID bit by bit
+                               memset(uid_resp, 0, 4);
+                               uint16_t uid_resp_bits = 0;
+                               uint16_t collision_answer_offset = 0;
+                               // anti-collision-loop:
+                               while (Demod.collisionPos) {
+                                       Dbprintf("Multiple tags detected. Collision after Bit %d", Demod.collisionPos);
+                                       for (uint16_t i = collision_answer_offset; i < Demod.collisionPos; i++, uid_resp_bits++) {      // add valid UID bits before collision point
+                                               uint16_t UIDbit = (resp[i/8] >> (i % 8)) & 0x01;
+                                               uid_resp[uid_resp_bits / 8] |= UIDbit << (uid_resp_bits % 8);
+                                       }
+                                       uid_resp[uid_resp_bits/8] |= 1 << (uid_resp_bits % 8);                                  // next time select the card(s) with a 1 in the collision position
+                                       uid_resp_bits++;
+                                       // construct anticollosion command:
+                                       sel_uid[1] = ((2 + uid_resp_bits/8) << 4) | (uid_resp_bits & 0x07);     // length of data in bytes and bits
+                                       for (uint16_t i = 0; i <= uid_resp_bits/8; i++) {
+                                               sel_uid[2+i] = uid_resp[i];
+                                       }
+                                       collision_answer_offset = uid_resp_bits%8;
+                                       ReaderTransmitBits(sel_uid, 16 + uid_resp_bits, NULL);
+                                       if (!ReaderReceiveOffset(resp, collision_answer_offset, resp_par)) return 0;

                                }
                                }

-                               uid_resp[uid_resp_bits/8] |= 1 << (uid_resp_bits % 8);                                  // next time select the card(s) with a 1 in the collision position
-                               uid_resp_bits++;
-                               // construct anticollosion command:
-                               sel_uid[1] = ((2 + uid_resp_bits/8) << 4) | (uid_resp_bits & 0x07);     // length of data in bytes and bits
-                               for (uint16_t i = 0; i <= uid_resp_bits/8; i++) {
-                                       sel_uid[2+i] = uid_resp[i];
+                               // finally, add the last bits and BCC of the UID
+                               for (uint16_t i = collision_answer_offset; i < (Demod.len-1)*8; i++, uid_resp_bits++) {
+                                       uint16_t UIDbit = (resp[i/8] >> (i%8)) & 0x01;
+                                       uid_resp[uid_resp_bits/8] |= UIDbit << (uid_resp_bits % 8);

                                }
                                }

-                               collision_answer_offset = uid_resp_bits%8;
-                               ReaderTransmitBits(sel_uid, 16 + uid_resp_bits, NULL);
-                               if (!ReaderReceiveOffset(resp, collision_answer_offset, resp_par)) return 0;
-                       }
-                       // finally, add the last bits and BCC of the UID
-                       for (uint16_t i = collision_answer_offset; i < (Demod.len-1)*8; i++, uid_resp_bits++) {
-                               uint16_t UIDbit = (resp[i/8] >> (i%8)) & 0x01;
-                               uid_resp[uid_resp_bits/8] |= UIDbit << (uid_resp_bits % 8);
-                       }

 
 

-               } else {                // no collision, use the response to SELECT_ALL as current uid
-                       memcpy(uid_resp, resp, 4);
-               }
+                       } else {                // no collision, use the response to SELECT_ALL as current uid
+                               memcpy(uid_resp, resp, 4);
+                       }
+                       

                } else {
                        if (cascade_level < num_cascades - 1) {
                                uid_resp[0] = 0x88;
                } else {
                        if (cascade_level < num_cascades - 1) {
                                uid_resp[0] = 0x88;


@@ -1973,9 +1975,8 @@ int iso14443a_select_card(byte_t *uid_ptr, iso14a_card_select_t *p_hi14a_card, u
                uid_resp_len = 4;
 
                // calculate crypto UID. Always use last 4 Bytes.
                uid_resp_len = 4;
 
                // calculate crypto UID. Always use last 4 Bytes.

-               if(cuid_ptr) {
+               if(cuid_ptr)

                        *cuid_ptr = bytes_to_num(uid_resp, 4);
                        *cuid_ptr = bytes_to_num(uid_resp, 4);

-               }

 
                // Construct SELECT UID command
                sel_uid[1] = 0x70;                                                                                                      // transmitting a full UID (1 Byte cmd, 1 Byte NVB, 4 Byte UID, 1 Byte BCC, 2 Bytes CRC)
 
                // Construct SELECT UID command
                sel_uid[1] = 0x70;                                                                                                      // transmitting a full UID (1 Byte cmd, 1 Byte NVB, 4 Byte UID, 1 Byte BCC, 2 Bytes CRC)


@@ -1986,6 +1987,7 @@ int iso14443a_select_card(byte_t *uid_ptr, iso14a_card_select_t *p_hi14a_card, u
 
                // Receive the SAK
                if (!ReaderReceive(resp, resp_par)) return 0;
 
                // Receive the SAK
                if (!ReaderReceive(resp, resp_par)) return 0;

+               

                sak = resp[0];
 
                // Test if more parts of the uid are coming
                sak = resp[0];
 
                // Test if more parts of the uid are coming


@@ -1998,9 +2000,8 @@ int iso14443a_select_card(byte_t *uid_ptr, iso14a_card_select_t *p_hi14a_card, u
                        uid_resp_len = 3;
                }
 
                        uid_resp_len = 3;
                }
 

-               if(uid_ptr && anticollision) {
+               if(uid_ptr && anticollision)

                        memcpy(uid_ptr + (cascade_level*3), uid_resp, uid_resp_len);
                        memcpy(uid_ptr + (cascade_level*3), uid_resp, uid_resp_len);

-               }

 
                if(p_hi14a_card) {
                        memcpy(p_hi14a_card->uid + (cascade_level*3), uid_resp, uid_resp_len);
 
                if(p_hi14a_card) {
                        memcpy(p_hi14a_card->uid + (cascade_level*3), uid_resp, uid_resp_len);


@@ -2021,7 +2022,6 @@ int iso14443a_select_card(byte_t *uid_ptr, iso14a_card_select_t *p_hi14a_card, u
        ReaderTransmit(rats, sizeof(rats), NULL);
 
        if (!(len = ReaderReceive(resp, resp_par))) return 0;
        ReaderTransmit(rats, sizeof(rats), NULL);
 
        if (!(len = ReaderReceive(resp, resp_par))) return 0;

-

        
        if(p_hi14a_card) {
                memcpy(p_hi14a_card->ats, resp, sizeof(p_hi14a_card->ats));
        
        if(p_hi14a_card) {
                memcpy(p_hi14a_card->ats, resp, sizeof(p_hi14a_card->ats));


@@ -2219,7 +2219,7 @@ void ReaderMifare(bool first_try, uint8_t block )
        //uint8_t mf_auth[]    = { 0x60,0x05, 0x58, 0x2c };
        uint8_t mf_auth[]    = { 0x60,0x00, 0x00, 0x00 };
        uint8_t mf_nr_ar[]   = { 0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00 };
        //uint8_t mf_auth[]    = { 0x60,0x05, 0x58, 0x2c };
        uint8_t mf_auth[]    = { 0x60,0x00, 0x00, 0x00 };
        uint8_t mf_nr_ar[]   = { 0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00 };

-       static uint8_t mf_nr_ar3;
+       static uint8_t mf_nr_ar3 = 0;

 
        mf_auth[1] = block;
        AppendCrc14443a(mf_auth, 2);
 
        mf_auth[1] = block;
        AppendCrc14443a(mf_auth, 2);


@@ -2227,14 +2227,6 @@ void ReaderMifare(bool first_try, uint8_t block )
        uint8_t receivedAnswer[MAX_MIFARE_FRAME_SIZE] = {0x00};
        uint8_t receivedAnswerPar[MAX_MIFARE_PARITY_SIZE] = {0x00};
 
        uint8_t receivedAnswer[MAX_MIFARE_FRAME_SIZE] = {0x00};
        uint8_t receivedAnswerPar[MAX_MIFARE_PARITY_SIZE] = {0x00};
 

-       if (first_try)
-               iso14443a_setup(FPGA_HF_ISO14443A_READER_MOD);
-       
-       // free eventually allocated BigBuf memory. We want all for tracing.
-       BigBuf_free();
-       clear_trace();
-       set_tracing(TRUE);
-

        byte_t nt_diff = 0;
        uint8_t par[1] = {0};   // maximum 8 Bytes to be sent here, 1 byte parity is therefore enough
        static byte_t par_low = 0;
        byte_t nt_diff = 0;
        uint8_t par[1] = {0};   // maximum 8 Bytes to be sent here, 1 byte parity is therefore enough
        static byte_t par_low = 0;


@@ -2248,49 +2240,62 @@ void ReaderMifare(bool first_try, uint8_t block )
        byte_t par_list[8] = {0x00};
        byte_t ks_list[8] = {0x00};
 
        byte_t par_list[8] = {0x00};
        byte_t ks_list[8] = {0x00};
 

-       #define PRNG_SEQUENCE_LENGTH  (1 << 16);

        static uint32_t sync_time = 0;
        static int32_t sync_cycles = 0;
        int catch_up_cycles = 0;
        int last_catch_up = 0;
        static uint32_t sync_time = 0;
        static int32_t sync_cycles = 0;
        int catch_up_cycles = 0;
        int last_catch_up = 0;

-       uint16_t elapsed_prng_sequences = 0;
+       uint16_t elapsed_prng_sequences = 1;

        uint16_t consecutive_resyncs = 0;
        int isOK = 0;
 
        uint16_t consecutive_resyncs = 0;
        int isOK = 0;
 

-       if (first_try) { 
-               mf_nr_ar3 = 0;
-               sync_time = GetCountSspClk() & 0xfffffff8;
-               sync_cycles = PRNG_SEQUENCE_LENGTH; //65536;    //0x10000                       // theory: Mifare Classic's random generator repeats every 2^16 cycles (and so do the nonces).
-               nt_attacked = 0;
-               par[0] = 0;
-       }
-       else {
-               // we were unsuccessful on a previous call. Try another READER nonce (first 3 parity bits remain the same)
-               mf_nr_ar3++;
-               mf_nr_ar[3] = mf_nr_ar3;
-               par[0] = par_low;
-       }
-
-       LED_A_ON();
-       LED_B_OFF();
-       LED_C_OFF();
-       
-
+       #define PRNG_SEQUENCE_LENGTH  (1 << 16);

        #define MAX_UNEXPECTED_RANDOM   4               // maximum number of unexpected (i.e. real) random numbers when trying to sync. Then give up.
        #define MAX_SYNC_TRIES                  32
        #define NUM_DEBUG_INFOS                 8               // per strategy
        #define MAX_STRATEGY                    3
        #define MAX_UNEXPECTED_RANDOM   4               // maximum number of unexpected (i.e. real) random numbers when trying to sync. Then give up.
        #define MAX_SYNC_TRIES                  32
        #define NUM_DEBUG_INFOS                 8               // per strategy
        #define MAX_STRATEGY                    3

+

        uint16_t unexpected_random = 0;
        uint16_t sync_tries = 0;
        int16_t debug_info_nr = -1;
        uint16_t strategy = 0;
        uint16_t unexpected_random = 0;
        uint16_t sync_tries = 0;
        int16_t debug_info_nr = -1;
        uint16_t strategy = 0;

-       int32_t debug_info[MAX_STRATEGY][NUM_DEBUG_INFOS];
+       int32_t debug_info[MAX_STRATEGY+1][NUM_DEBUG_INFOS];

        uint32_t select_time = 0;
        uint32_t halt_time = 0;
        uint32_t select_time = 0;
        uint32_t halt_time = 0;

-  
-       for(uint16_t i = 0; TRUE; ++i) {
+       //uint8_t caller[7] = {0};      
+
+       // init to zero.
+       for (uint16_t i = 0; i < MAX_STRATEGY+1; ++i)
+               for(uint16_t j = 0; j < NUM_DEBUG_INFOS; ++j)
+                       debug_info[i][j] = 0;
+       
+       LED_A_ON();
+       LED_B_OFF();
+       LED_C_OFF();
+       
+       if (first_try)
+               iso14443a_setup(FPGA_HF_ISO14443A_READER_MOD);
+       
+       // free eventually allocated BigBuf memory. We want all for tracing.
+       BigBuf_free();
+       clear_trace();
+       set_tracing(TRUE);
+
+       if (first_try) { 
+               sync_time = GetCountSspClk() & 0xfffffff8;
+               sync_cycles = PRNG_SEQUENCE_LENGTH; //65536;    //0x10000                       // theory: Mifare Classic's random generator repeats every 2^16 cycles (and so do the nonces).
+               mf_nr_ar3 = 0;                  
+               nt_attacked = 0;
+               par[0] = 0;
+       } else {
+               // we were unsuccessful on a previous call. Try another READER nonce (first 3 parity bits remain the same)
+               mf_nr_ar3++;
+               mf_nr_ar[3] = mf_nr_ar3;
+               par[0] = par_low;
+       }

                
                

-               LED_C_ON();
+       LED_C_ON(); 
+       for(uint16_t i = 0; TRUE; ++i) {
+

                WDT_HIT();
 
                // Test if the action was cancelled
                WDT_HIT();
 
                // Test if the action was cancelled


@@ -2300,12 +2305,12 @@ void ReaderMifare(bool first_try, uint8_t block )
                }
                
                if (strategy == 2) {
                }
                
                if (strategy == 2) {

-                       // test with additional hlt command
+                       // test with additional halt command

                        halt_time = 0;
                        int len = mifare_sendcmd_short(NULL, false, 0x50, 0x00, receivedAnswer, receivedAnswerPar, &halt_time);
                        halt_time = 0;
                        int len = mifare_sendcmd_short(NULL, false, 0x50, 0x00, receivedAnswer, receivedAnswerPar, &halt_time);

-                       if (len && MF_DBGLEVEL >= 3) {
-                               Dbprintf("Unexpected response of %d bytes to hlt command (additional debugging).", len);
-                       }
+
+                       if (len && MF_DBGLEVEL >= 3)
+                               Dbprintf("Unexpected response of %d bytes to halt command (additional debugging).\n", len);

                }
 
                if (strategy == 3) {
                }
 
                if (strategy == 3) {


@@ -2314,28 +2319,35 @@ void ReaderMifare(bool first_try, uint8_t block )
                        SpinDelay(200);
                        iso14443a_setup(FPGA_HF_ISO14443A_READER_MOD);
                        SpinDelay(100);
                        SpinDelay(200);
                        iso14443a_setup(FPGA_HF_ISO14443A_READER_MOD);
                        SpinDelay(100);

+                       sync_time = GetCountSspClk() & 0xfffffff8;

                        WDT_HIT();
                }
                
                        WDT_HIT();
                }
                

-               if(!iso14443a_select_card(uid, NULL, &cuid, true, 0)) {
-                       if (MF_DBGLEVEL >= 1)   Dbprintf("Mifare: Can't select card");
+               if (!iso14443a_select_card(uid, NULL, &cuid, true, 0)) {
+                       if (MF_DBGLEVEL >= 1) Dbprintf("Mifare: Can't select card\n");

                        continue;
                }
                        continue;
                }

-               select_time = GetCountSspClk();

 
 

+               select_time = GetCountSspClk() & 0xfffffff8;

                elapsed_prng_sequences = 1;
                elapsed_prng_sequences = 1;

+               

                if (debug_info_nr == -1) {
                if (debug_info_nr == -1) {

+                       

                        sync_time = (sync_time & 0xfffffff8) + sync_cycles + catch_up_cycles;
                        catch_up_cycles = 0;
                        sync_time = (sync_time & 0xfffffff8) + sync_cycles + catch_up_cycles;
                        catch_up_cycles = 0;

-
+                                                                       

                        // if we missed the sync time already, advance to the next nonce repeat
                        // if we missed the sync time already, advance to the next nonce repeat

+                       WDT_HIT();

                        while(GetCountSspClk() > sync_time) {
                        while(GetCountSspClk() > sync_time) {

-                               elapsed_prng_sequences++;
+                               ++elapsed_prng_sequences;

                                sync_time = (sync_time & 0xfffffff8) + sync_cycles;
                                sync_time = (sync_time & 0xfffffff8) + sync_cycles;

-                       }                       
-
+                               //sync_time += sync_cycles;
+                               //sync_time &= 0xfffffff8;
+                       }
+                       WDT_HIT();

                        // Transmit MIFARE_CLASSIC_AUTH at synctime. Should result in returning the same tag nonce (== nt_attacked) 
                        // Transmit MIFARE_CLASSIC_AUTH at synctime. Should result in returning the same tag nonce (== nt_attacked) 

-                       ReaderTransmit(mf_auth, sizeof(mf_auth), &sync_time);
+                       ReaderTransmit(mf_auth, sizeof(mf_auth), &sync_time);                   
+                       if (MF_DBGLEVEL == 2) Dbprintf("sync_time %d \n", sync_time);

                        
                } else {
                        // collect some information on tag nonces for debugging:
                        
                } else {
                        // collect some information on tag nonces for debugging:


@@ -2357,10 +2369,8 @@ void ReaderMifare(bool first_try, uint8_t block )
                }                       
 
                // Receive the (4 Byte) "random" nonce
                }                       
 
                // Receive the (4 Byte) "random" nonce

-               if (!ReaderReceive(receivedAnswer, receivedAnswerPar)) {
-                       if (MF_DBGLEVEL >= 1)   Dbprintf("Mifare: Couldn't receive tag nonce");
+               if (!ReaderReceive(receivedAnswer, receivedAnswerPar))

                        continue;
                        continue;

-                 }

 
                previous_nt = nt;
                nt = bytes_to_num(receivedAnswer, 4);
 
                previous_nt = nt;
                nt = bytes_to_num(receivedAnswer, 4);


@@ -2382,6 +2392,7 @@ void ReaderMifare(bool first_try, uint8_t block )
                                                continue;               // continue trying...
                                        }
                                }
                                                continue;               // continue trying...
                                        }
                                }

+                               

                                if (++sync_tries > MAX_SYNC_TRIES) {
                                        if (strategy > MAX_STRATEGY || MF_DBGLEVEL < 3) {
                                                isOK = -4;                      // Card's PRNG runs at an unexpected frequency or resets unexpectedly
                                if (++sync_tries > MAX_SYNC_TRIES) {
                                        if (strategy > MAX_STRATEGY || MF_DBGLEVEL < 3) {
                                                isOK = -4;                      // Card's PRNG runs at an unexpected frequency or resets unexpectedly


@@ -2389,44 +2400,53 @@ void ReaderMifare(bool first_try, uint8_t block )
                                        } else {                                // continue for a while, just to collect some debug info
                                                ++debug_info_nr;
                                                debug_info[strategy][debug_info_nr] = nt_distance;                                              
                                        } else {                                // continue for a while, just to collect some debug info
                                                ++debug_info_nr;
                                                debug_info[strategy][debug_info_nr] = nt_distance;                                              

-                                               if (debug_info_nr == NUM_DEBUG_INFOS) {
+                                               if (debug_info_nr == NUM_DEBUG_INFOS-1) {

                                                        ++strategy;
                                                        debug_info_nr = 0;
                                                }
                                                continue;
                                        }
                                }
                                                        ++strategy;
                                                        debug_info_nr = 0;
                                                }
                                                continue;
                                        }
                                }

+                               

                                sync_cycles = (sync_cycles - nt_distance/elapsed_prng_sequences);
                                sync_cycles = (sync_cycles - nt_distance/elapsed_prng_sequences);

-                               if (sync_cycles <= 0) {
+                               if (sync_cycles <= 0)

                                        sync_cycles += PRNG_SEQUENCE_LENGTH;
                                        sync_cycles += PRNG_SEQUENCE_LENGTH;

-                               }
-                               if (MF_DBGLEVEL >= 3) {
+                               
+                               if (MF_DBGLEVEL >= 2)

                                        Dbprintf("calibrating in cycle %d. nt_distance=%d, elapsed_prng_sequences=%d, new sync_cycles: %d\n", i, nt_distance, elapsed_prng_sequences, sync_cycles);
                                        Dbprintf("calibrating in cycle %d. nt_distance=%d, elapsed_prng_sequences=%d, new sync_cycles: %d\n", i, nt_distance, elapsed_prng_sequences, sync_cycles);

-                               }
+

                                continue;
                        }
                }
 
                if ((nt != nt_attacked) && nt_attacked) {       // we somehow lost sync. Try to catch up again...
                                continue;
                        }
                }
 
                if ((nt != nt_attacked) && nt_attacked) {       // we somehow lost sync. Try to catch up again...

+                       

                        catch_up_cycles = -dist_nt(nt_attacked, nt);
                        if (catch_up_cycles == 99999) {                 // invalid nonce received. Don't resync on that one.
                                catch_up_cycles = 0;
                                continue;
                        }
                        catch_up_cycles = -dist_nt(nt_attacked, nt);
                        if (catch_up_cycles == 99999) {                 // invalid nonce received. Don't resync on that one.
                                catch_up_cycles = 0;
                                continue;
                        }

+                       
+                       // average? 

                        catch_up_cycles /= elapsed_prng_sequences;
                        catch_up_cycles /= elapsed_prng_sequences;

+               

                        if (catch_up_cycles == last_catch_up) {
                                ++consecutive_resyncs;
                        if (catch_up_cycles == last_catch_up) {
                                ++consecutive_resyncs;

-                       }
-                       else {
+                       } else {

                                last_catch_up = catch_up_cycles;
                            consecutive_resyncs = 0;
                        }
                                last_catch_up = catch_up_cycles;
                            consecutive_resyncs = 0;
                        }

+                       sync_cycles += catch_up_cycles;
+                       

                        if (consecutive_resyncs < 3) {
                        if (consecutive_resyncs < 3) {

-                               if (MF_DBGLEVEL >= 3) Dbprintf("Lost sync in cycle %d. nt_distance=%d. Consecutive Resyncs = %d. Trying one time catch up...\n", i, -catch_up_cycles, consecutive_resyncs);
-                       }
-                       else {  
-                               sync_cycles = sync_cycles + catch_up_cycles;
-                               if (MF_DBGLEVEL >= 3) Dbprintf("Lost sync in cycle %d for the fourth time consecutively (nt_distance = %d). Adjusting sync_cycles to %d.\n", i, -catch_up_cycles, sync_cycles);
+                               if (MF_DBGLEVEL >= 3)
+                                       Dbprintf("Lost sync in cycle %d. nt_distance=%d. Consecutive Resyncs = %d. Trying one time catch up...\n", i, -catch_up_cycles, consecutive_resyncs);
+                       } else {        
+                               sync_cycles += catch_up_cycles;
+                               
+                               if (MF_DBGLEVEL >= 3) 
+                                       Dbprintf("Lost sync in cycle %d for the fourth time consecutively (nt_distance = %d). Adjusting sync_cycles to %d.\n", i, -catch_up_cycles, sync_cycles);
+

                                last_catch_up = 0;
                                catch_up_cycles = 0;
                                consecutive_resyncs = 0;
                                last_catch_up = 0;
                                catch_up_cycles = 0;
                                consecutive_resyncs = 0;


@@ -2474,15 +2494,20 @@ void ReaderMifare(bool first_try, uint8_t block )
        mf_nr_ar[3] &= 0x1F;
 
        WDT_HIT();
        mf_nr_ar[3] &= 0x1F;
 
        WDT_HIT();

-               
+

        if (isOK == -4) {
        if (isOK == -4) {

-               if (MF_DBGLEVEL >= 3) {
-                       for (uint16_t i = 0; i <= MAX_STRATEGY; ++i) {
-                               for(uint16_t j = 0; j < NUM_DEBUG_INFOS; ++j) {
-                                       Dbprintf("collected debug info[%d][%d] = %d", i, j, debug_info[i][j]);
-                               }
-                       }
-               }
+               for (uint16_t i = 0; i < MAX_STRATEGY+1; ++i)
+                       for(uint16_t j = 0; j < NUM_DEBUG_INFOS; ++j)
+                               Dbprintf("info[%d][%d] = %d", i, j, debug_info[i][j]);
+       }
+       
+       // reset sync_time.
+       if ( isOK == 1) {
+               sync_time =     0;
+               sync_cycles = 0;
+               mf_nr_ar3 = 0;          
+               nt_attacked = 0;
+               par[0] = 0;

        }
        
        byte_t buf[28] = {0x00};
        }
        
        byte_t buf[28] = {0x00};


@@ -2494,10 +2519,8 @@ void ReaderMifare(bool first_try, uint8_t block )
                
        cmd_send(CMD_ACK,isOK,0,0,buf,28);
 
                
        cmd_send(CMD_ACK,isOK,0,0,buf,28);
 

-       // Thats it...

        FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
        LEDsoff();
        FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
        LEDsoff();

-

        set_tracing(FALSE);
 }
 
        set_tracing(FALSE);
 }