X-Git-Url: http://git.zerfleddert.de/cgi-bin/gitweb.cgi/proxmark3-svn/blobdiff_plain/f7e3ed82874bfd8951c90536bd7185d599d6dbf8..37824afe63d044fbaa37aaa5c0f84164216cb9c4:/armsrc/hitag2.c diff --git a/armsrc/hitag2.c b/armsrc/hitag2.c index 1278b758..719164d1 100644 --- a/armsrc/hitag2.c +++ b/armsrc/hitag2.c @@ -1,178 +1,80 @@ -/* - * Hitag2 emulation - * - * Contains state and functions for an emulated Hitag2 tag. Offers an entry - * point to handle commands, needs a callback to send response. - * - * (c) 2009 Henryk Plötz - */ +//----------------------------------------------------------------------------- +// 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. +//----------------------------------------------------------------------------- +// Hitag2 emulation (preliminary test version) +// +// (c) 2009 Henryk Plötz +//----------------------------------------------------------------------------- +// Hitag2 complete rewrite of the code +// - Fixed modulation/encoding issues +// - Rewrote code for transponder emulation +// - Added snooping of transponder communication +// - Added reader functionality +// +// (c) 2012 Roel Verdult +//----------------------------------------------------------------------------- #include "proxmark3.h" #include "apps.h" #include "util.h" - #include "hitag2.h" +#include "string.h" +#include "BigBuf.h" + +static bool bQuiet; + +static bool bCrypto; +static bool bAuthenticating; +static bool bPwd; +static bool bSuccessful; + -struct hitag2_cipher_state { - uint64_t state; -}; struct hitag2_tag { uint32_t uid; enum { - TAG_STATE_RESET, // Just powered up, awaiting GetSnr - TAG_STATE_ACTIVATING, // In activation phase (password mode), sent UID, awaiting reader password - TAG_STATE_AUTHENTICATING, // In activation phase (crypto mode), awaiting reader authentication - TAG_STATE_ACTIVATED, // Activation complete, awaiting read/write commands - TAG_STATE_WRITING, // In write command, awaiting sector contents to be written + TAG_STATE_RESET = 0x01, // Just powered up, awaiting GetSnr + TAG_STATE_ACTIVATING = 0x02 , // In activation phase (password mode), sent UID, awaiting reader password + TAG_STATE_ACTIVATED = 0x03, // Activation complete, awaiting read/write commands + TAG_STATE_WRITING = 0x04, // In write command, awaiting sector contents to be written } state; unsigned int active_sector; - char crypto_active; - struct hitag2_cipher_state cs; - char sectors[8][4]; + byte_t crypto_active; + uint64_t cs; + byte_t sectors[12][4]; }; -static void hitag2_cipher_reset(struct hitag2_tag *tag, const char *challenge); -static int hitag2_cipher_authenticate(struct hitag2_cipher_state *cs, const char *authenticator); -static int hitag2_cipher_transcrypt(struct hitag2_cipher_state *cs, char *data, unsigned int bytes, unsigned int bits); - -static struct hitag2_tag tag; -static const struct hitag2_tag resetdata = { - .state = TAG_STATE_RESET, - .sectors = { // Password mode: | Crypto mode: - [0] = { 0x35, 0x33, 0x70, 0x11}, // UID | UID - [1] = { 0x4d, 0x49, 0x4b, 0x52}, // Password RWD | 32 bit LSB key - [2] = { 0x20, 0xf0, 0x4f, 0x4e}, // Reserved | 16 bit MSB key, 16 bit reserved - [3] = { 0x0e, 0xaa, 'H', 'T'}, // Configuration, password TAG | Configuration, password TAG - }, +static struct hitag2_tag tag = { + .state = TAG_STATE_RESET, + .sectors = { // Password mode: | Crypto mode: + [0] = { 0x02, 0x4e, 0x02, 0x20}, // UID | UID + [1] = { 0x4d, 0x49, 0x4b, 0x52}, // Password RWD | 32 bit LSB key + [2] = { 0x20, 0xf0, 0x4f, 0x4e}, // Reserved | 16 bit MSB key, 16 bit reserved + [3] = { 0x0e, 0xaa, 0x48, 0x54}, // Configuration, password TAG | Configuration, password TAG + [4] = { 0x46, 0x5f, 0x4f, 0x4b}, // Data: F_OK + [5] = { 0x55, 0x55, 0x55, 0x55}, // Data: UUUU + [6] = { 0xaa, 0xaa, 0xaa, 0xaa}, // Data: .... + [7] = { 0x55, 0x55, 0x55, 0x55}, // Data: UUUU + [8] = { 0x00, 0x00, 0x00, 0x00}, // RSK Low + [9] = { 0x00, 0x00, 0x00, 0x00}, // RSK High + [10] = { 0x00, 0x00, 0x00, 0x00}, // RCF + [11] = { 0x00, 0x00, 0x00, 0x00}, // SYNC + }, }; -int hitag2_reset(void) -{ - tag.state = TAG_STATE_RESET; - tag.crypto_active = 0; - return 0; -} - -int hitag2_init(void) -{ - memcpy(&tag, &resetdata, sizeof(tag)); - hitag2_reset(); - return 0; -} - -int hitag2_handle_command(const char* data, const int length, hitag2_response_callback_t cb, void *cb_cookie) -{ - (void)data; (void)length; (void)cb; (void)cb_cookie; - int retry = 0, done = 0, result=0; - char temp[10]; - - if(tag.crypto_active && length < sizeof(temp)*8) { - /* Decrypt command */ - memcpy(temp, data, (length+7)/8); - hitag2_cipher_transcrypt(&(tag.cs), temp, length/8, length%8); - data = temp; - } - - -handle_command_retry: - switch(tag.state) { - case TAG_STATE_RESET: - if(length == 5 && data[0] == 0xC0) { - /* Received 11000 from the reader, request for UID, send UID */ - result=cb(tag.sectors[0], sizeof(tag.sectors[0])*8, 208, cb_cookie); - done=1; - if(tag.sectors[3][0] & 0x08) { - tag.state=TAG_STATE_AUTHENTICATING; - } else { - tag.state=TAG_STATE_ACTIVATING; - } - } - break; - case TAG_STATE_ACTIVATING: - if(length == 0x20) { - /* Received RWD password, respond with configuration and our password */ - result=cb(tag.sectors[3], sizeof(tag.sectors[3])*8, 208, cb_cookie); - done=1; - tag.state=TAG_STATE_ACTIVATED; - } - break; - case TAG_STATE_AUTHENTICATING: - if(length == 0x40) { - /* Received initialisation vector || authentication token, fire up cipher, send our password */ - hitag2_cipher_reset(&tag, data); - if(hitag2_cipher_authenticate(&(tag.cs), data+4)) { - char response_enc[4]; - memcpy(response_enc, tag.sectors[3], 4); - hitag2_cipher_transcrypt(&(tag.cs), response_enc, 4, 0); - result=cb(response_enc, 4*8, 208, cb_cookie); - done=1; - tag.crypto_active = 1; - tag.state = TAG_STATE_ACTIVATED; - } else { - /* The reader failed to authenticate, do nothing */ - DbpString("Reader authentication failed"); - } - } - break; - case TAG_STATE_ACTIVATED: - if(length == 10) { - if( ((data[0] & 0xC0) == 0xC0) && ((data[0] & 0x06) == 0) ) { - /* Read command: 11xx x00y yy with yyy == ~xxx, xxx is sector number */ - unsigned int sector = (~( ((data[0]<<2)&0x04) | ((data[1]>>6)&0x03) ) & 0x07); - if(sector == ( (data[0]>>3)&0x07 ) ) { - memcpy(temp, tag.sectors[sector], 4); - if(tag.crypto_active) { - hitag2_cipher_transcrypt(&(tag.cs), temp, 4, 0); - } - /* Respond with contents of sector sector */ - result = cb(temp, 4*8, 208, cb_cookie); - done=1; - } else { - /* transmission error */ - DbpString("Transmission error (read) in activated state"); - } - } else if( ((data[0] & 0xC0) == 0x80) && ((data[0] & 0x06) == 2) ) { - /* Write command: 10xx x01y yy with yyy == ~xxx, xxx is sector number */ - unsigned int sector = (~( ((data[0]<<2)&0x04) | ((data[1]>>6)&0x03) ) & 0x07); - if(sector == ( (data[0]>>3)&0x07 ) ) { - /* Prepare write, acknowledge by repeating command */ - if(tag.crypto_active) { - hitag2_cipher_transcrypt(&(tag.cs), temp, length/8, length%8); - } - result = cb(data, length, 208, cb_cookie); - done=1; - tag.active_sector = sector; - tag.state=TAG_STATE_WRITING; - } else { - /* transmission error */ - DbpString("Transmission error (write) in activated state"); - } - } - - } - case TAG_STATE_WRITING: - if(length == 32) { - /* These are the sector contents to be written. We don't have to do anything else. */ - memcpy(tag.sectors[tag.active_sector], data, length/8); - tag.state=TAG_STATE_ACTIVATED; - done=1; - } - } - - if(!done && !retry) { - /* We didn't respond, maybe our state is faulty. Reset and try again. */ - retry=1; - if(tag.crypto_active) { - /* Restore undeciphered data */ - memcpy(temp, data, (length+7)/8); - } - hitag2_reset(); - goto handle_command_retry; - } +// ToDo: define a meaningful maximum size for auth_table. The bigger this is, the lower will be the available memory for traces. +// Historically it used to be FREE_BUFFER_SIZE, which was 2744. +#define AUTH_TABLE_LENGTH 2744 +static byte_t* auth_table; +static size_t auth_table_pos = 0; +static size_t auth_table_len = AUTH_TABLE_LENGTH; - return result; -} +static byte_t password[4]; +static byte_t NrAr[8]; +static byte_t key[8]; +static uint64_t cipher_state; /* Following is a modified version of cryptolib.com/ciphers/hitag2/ */ // Software optimized 48-bit Philips/NXP Mifare Hitag2 PCF7936/46/47/52 stream cipher algorithm by I.C. Wiener 2006-2007. @@ -250,42 +152,1236 @@ static u32 _hitag2_byte (u64 * x) return c; } +static int hitag2_reset(void) +{ + tag.state = TAG_STATE_RESET; + tag.crypto_active = 0; + return 0; +} -/* Cipher/tag glue code: */ +static int hitag2_init(void) +{ +// memcpy(&tag, &resetdata, sizeof(tag)); + hitag2_reset(); + return 0; +} -static void hitag2_cipher_reset(struct hitag2_tag *tag, const char *iv) +static void hitag2_cipher_reset(struct hitag2_tag *tag, const byte_t *iv) { - uint64_t key = ((uint64_t)tag->sectors[2][2]) | - ((uint64_t)tag->sectors[2][3] << 8) | - ((uint64_t)tag->sectors[1][0] << 16) | - ((uint64_t)tag->sectors[1][1] << 24) | - ((uint64_t)tag->sectors[1][2] << 32) | - ((uint64_t)tag->sectors[1][3] << 40); - uint32_t uid = ((uint32_t)tag->sectors[0][0]) | - ((uint32_t)tag->sectors[0][1] << 8) | - ((uint32_t)tag->sectors[0][2] << 16) | - ((uint32_t)tag->sectors[0][3] << 24); + uint64_t key = ((uint64_t)tag->sectors[2][2]) | + ((uint64_t)tag->sectors[2][3] << 8) | + ((uint64_t)tag->sectors[1][0] << 16) | + ((uint64_t)tag->sectors[1][1] << 24) | + ((uint64_t)tag->sectors[1][2] << 32) | + ((uint64_t)tag->sectors[1][3] << 40); + uint32_t uid = ((uint32_t)tag->sectors[0][0]) | + ((uint32_t)tag->sectors[0][1] << 8) | + ((uint32_t)tag->sectors[0][2] << 16) | + ((uint32_t)tag->sectors[0][3] << 24); uint32_t iv_ = (((uint32_t)(iv[0]))) | (((uint32_t)(iv[1])) << 8) | (((uint32_t)(iv[2])) << 16) | (((uint32_t)(iv[3])) << 24); - tag->cs.state = _hitag2_init(rev64(key), rev32(uid), rev32(iv_)); + tag->cs = _hitag2_init(rev64(key), rev32(uid), rev32(iv_)); } -static int hitag2_cipher_authenticate(struct hitag2_cipher_state *cs, const char *authenticator_is) +static int hitag2_cipher_authenticate(uint64_t* cs, const byte_t *authenticator_is) { - char authenticator_should[4]; - authenticator_should[0] = ~_hitag2_byte(&(cs->state)); - authenticator_should[1] = ~_hitag2_byte(&(cs->state)); - authenticator_should[2] = ~_hitag2_byte(&(cs->state)); - authenticator_should[3] = ~_hitag2_byte(&(cs->state)); - return memcmp(authenticator_should, authenticator_is, 4) == 0; + byte_t authenticator_should[4]; + authenticator_should[0] = ~_hitag2_byte(cs); + authenticator_should[1] = ~_hitag2_byte(cs); + authenticator_should[2] = ~_hitag2_byte(cs); + authenticator_should[3] = ~_hitag2_byte(cs); + return (memcmp(authenticator_should, authenticator_is, 4) == 0); } -static int hitag2_cipher_transcrypt(struct hitag2_cipher_state *cs, char *data, unsigned int bytes, unsigned int bits) +static int hitag2_cipher_transcrypt(uint64_t* cs, byte_t *data, unsigned int bytes, unsigned int bits) { int i; - for(i=0; istate)); - for(i=0; istate)) << (7-i); + for(i=0; i 36 */ +#define HITAG_T_LOW 8 /* T_LOW should be 4..10 */ +#define HITAG_T_0_MIN 15 /* T[0] should be 18..22 */ +#define HITAG_T_1_MIN 25 /* T[1] should be 26..30 */ +//#define HITAG_T_EOF 40 /* T_EOF should be > 36 */ +#define HITAG_T_EOF 80 /* T_EOF should be > 36 */ +#define HITAG_T_WAIT_1 200 /* T_wresp should be 199..206 */ +#define HITAG_T_WAIT_2 90 /* T_wresp should be 199..206 */ +#define HITAG_T_WAIT_MAX 300 /* bit more than HITAG_T_WAIT_1 + HITAG_T_WAIT_2 */ + +#define HITAG_T_TAG_ONE_HALF_PERIOD 10 +#define HITAG_T_TAG_TWO_HALF_PERIOD 25 +#define HITAG_T_TAG_THREE_HALF_PERIOD 41 +#define HITAG_T_TAG_FOUR_HALF_PERIOD 57 + +#define HITAG_T_TAG_HALF_PERIOD 16 +#define HITAG_T_TAG_FULL_PERIOD 32 + +#define HITAG_T_TAG_CAPTURE_ONE_HALF 13 +#define HITAG_T_TAG_CAPTURE_TWO_HALF 25 +#define HITAG_T_TAG_CAPTURE_THREE_HALF 41 +#define HITAG_T_TAG_CAPTURE_FOUR_HALF 57 + + +static void hitag_send_bit(int bit) { + LED_A_ON(); + // Reset clock for the next bit + AT91C_BASE_TC0->TC_CCR = AT91C_TC_SWTRG; + + // Fixed modulation, earlier proxmark version used inverted signal + if(bit == 0) { + // Manchester: Unloaded, then loaded |__--| + LOW(GPIO_SSC_DOUT); + while(AT91C_BASE_TC0->TC_CV < T0*HITAG_T_TAG_HALF_PERIOD); + HIGH(GPIO_SSC_DOUT); + while(AT91C_BASE_TC0->TC_CV < T0*HITAG_T_TAG_FULL_PERIOD); + } else { + // Manchester: Loaded, then unloaded |--__| + HIGH(GPIO_SSC_DOUT); + while(AT91C_BASE_TC0->TC_CV < T0*HITAG_T_TAG_HALF_PERIOD); + LOW(GPIO_SSC_DOUT); + while(AT91C_BASE_TC0->TC_CV < T0*HITAG_T_TAG_FULL_PERIOD); + } + LED_A_OFF(); +} + +static void hitag_send_frame(const byte_t* frame, size_t frame_len) +{ + // Send start of frame + for(size_t i=0; i<5; i++) { + hitag_send_bit(1); + } + + // Send the content of the frame + for(size_t i=0; i> (7-(i%8)))&1); + } + + // Drop the modulation + LOW(GPIO_SSC_DOUT); +} + + +static void hitag2_handle_reader_command(byte_t* rx, const size_t rxlen, byte_t* tx, size_t* txlen) +{ + byte_t rx_air[HITAG_FRAME_LEN]; + + // Copy the (original) received frame how it is send over the air + memcpy(rx_air,rx,nbytes(rxlen)); + + if(tag.crypto_active) { + hitag2_cipher_transcrypt(&(tag.cs),rx,rxlen/8,rxlen%8); + } + + // Reset the transmission frame length + *txlen = 0; + + // Try to find out which command was send by selecting on length (in bits) + switch (rxlen) { + // Received 11000 from the reader, request for UID, send UID + case 05: { + // Always send over the air in the clear plaintext mode + if(rx_air[0] != 0xC0) { + // Unknown frame ? + return; + } + *txlen = 32; + memcpy(tx,tag.sectors[0],4); + tag.crypto_active = 0; + } + break; + + // Read/Write command: ..xx x..y yy with yyy == ~xxx, xxx is sector number + case 10: { + unsigned int sector = (~( ((rx[0]<<2)&0x04) | ((rx[1]>>6)&0x03) ) & 0x07); + // Verify complement of sector index + if(sector != ((rx[0]>>3)&0x07)) { + //DbpString("Transmission error (read/write)"); + return; + } + + switch (rx[0] & 0xC6) { + // Read command: 11xx x00y + case 0xC0: + memcpy(tx,tag.sectors[sector],4); + *txlen = 32; + break; + + // Inverted Read command: 01xx x10y + case 0x44: + for (size_t i=0; i<4; i++) { + tx[i] = tag.sectors[sector][i] ^ 0xff; + } + *txlen = 32; + break; + + // Write command: 10xx x01y + case 0x82: + // Prepare write, acknowledge by repeating command + memcpy(tx,rx,nbytes(rxlen)); + *txlen = rxlen; + tag.active_sector = sector; + tag.state=TAG_STATE_WRITING; + break; + + // Unknown command + default: + Dbprintf("Uknown command: %02x %02x",rx[0],rx[1]); + return; + break; + } + } + break; + + // Writing data or Reader password + case 32: { + if(tag.state == TAG_STATE_WRITING) { + // These are the sector contents to be written. We don't have to do anything else. + memcpy(tag.sectors[tag.active_sector],rx,nbytes(rxlen)); + tag.state=TAG_STATE_RESET; + return; + } else { + // Received RWD password, respond with configuration and our password + if(memcmp(rx,tag.sectors[1],4) != 0) { + DbpString("Reader password is wrong"); + return; + } + *txlen = 32; + memcpy(tx,tag.sectors[3],4); + } + } + break; + + // Received RWD authentication challenge and respnse + case 64: { + // Store the authentication attempt + if (auth_table_len < (AUTH_TABLE_LENGTH-8)) { + memcpy(auth_table+auth_table_len,rx,8); + auth_table_len += 8; + } + + // Reset the cipher state + hitag2_cipher_reset(&tag,rx); + // Check if the authentication was correct + if(!hitag2_cipher_authenticate(&(tag.cs),rx+4)) { + // The reader failed to authenticate, do nothing + Dbprintf("auth: %02x%02x%02x%02x%02x%02x%02x%02x Failed!",rx[0],rx[1],rx[2],rx[3],rx[4],rx[5],rx[6],rx[7]); + return; + } + // Succesful, but commented out reporting back to the Host, this may delay to much. + // Dbprintf("auth: %02x%02x%02x%02x%02x%02x%02x%02x OK!",rx[0],rx[1],rx[2],rx[3],rx[4],rx[5],rx[6],rx[7]); + + // Activate encryption algorithm for all further communication + tag.crypto_active = 1; + + // Use the tag password as response + memcpy(tx,tag.sectors[3],4); + *txlen = 32; + } + break; + } + +// LogTraceHitag(rx,rxlen,0,0,false); +// LogTraceHitag(tx,*txlen,0,0,true); + + if(tag.crypto_active) { + hitag2_cipher_transcrypt(&(tag.cs), tx, *txlen/8, *txlen%8); + } +} + +static void hitag_reader_send_bit(int bit) { + LED_A_ON(); + // Reset clock for the next bit + AT91C_BASE_TC0->TC_CCR = AT91C_TC_SWTRG; + + // Binary puls length modulation (BPLM) is used to encode the data stream + // This means that a transmission of a one takes longer than that of a zero + + // Enable modulation, which means, drop the the field + HIGH(GPIO_SSC_DOUT); + + // Wait for 4-10 times the carrier period + while(AT91C_BASE_TC0->TC_CV < T0*6); + // SpinDelayUs(8*8); + + // Disable modulation, just activates the field again + LOW(GPIO_SSC_DOUT); + + if(bit == 0) { + // Zero bit: |_-| + while(AT91C_BASE_TC0->TC_CV < T0*22); + // SpinDelayUs(16*8); + } else { + // One bit: |_--| + while(AT91C_BASE_TC0->TC_CV < T0*28); + // SpinDelayUs(22*8); + } + LED_A_OFF(); +} + + +static void hitag_reader_send_frame(const byte_t* frame, size_t frame_len) +{ + // Send the content of the frame + for(size_t i=0; i> (7-(i%8)))&1); + } + // Send EOF + AT91C_BASE_TC0->TC_CCR = AT91C_TC_SWTRG; + // Enable modulation, which means, drop the the field + HIGH(GPIO_SSC_DOUT); + // Wait for 4-10 times the carrier period + while(AT91C_BASE_TC0->TC_CV < T0*6); + // Disable modulation, just activates the field again + LOW(GPIO_SSC_DOUT); +} + +size_t blocknr; + +static bool hitag2_password(byte_t* rx, const size_t rxlen, byte_t* tx, size_t* txlen) { + // Reset the transmission frame length + *txlen = 0; + + // Try to find out which command was send by selecting on length (in bits) + switch (rxlen) { + // No answer, try to resurrect + case 0: { + // Stop if there is no answer (after sending password) + if (bPwd) { + DbpString("Password failed!"); + return false; + } + *txlen = 5; + memcpy(tx,"\xc0",nbytes(*txlen)); + } break; + + // Received UID, tag password + case 32: { + if (!bPwd) { + *txlen = 32; + memcpy(tx,password,4); + bPwd = true; + memcpy(tag.sectors[blocknr],rx,4); + blocknr++; + } else { + + if(blocknr == 1){ + //store password in block1, the TAG answers with Block3, but we need the password in memory + memcpy(tag.sectors[blocknr],tx,4); + }else{ + memcpy(tag.sectors[blocknr],rx,4); + } + + blocknr++; + if (blocknr > 7) { + DbpString("Read succesful!"); + bSuccessful = true; + return false; + } + *txlen = 10; + tx[0] = 0xc0 | (blocknr << 3) | ((blocknr^7) >> 2); + tx[1] = ((blocknr^7) << 6); + } + } break; + + // Unexpected response + default: { + Dbprintf("Uknown frame length: %d",rxlen); + return false; + } break; + } + return true; +} + +static bool hitag2_crypto(byte_t* rx, const size_t rxlen, byte_t* tx, size_t* txlen) { + // Reset the transmission frame length + *txlen = 0; + + if(bCrypto) { + hitag2_cipher_transcrypt(&cipher_state,rx,rxlen/8,rxlen%8); + } + + // Try to find out which command was send by selecting on length (in bits) + switch (rxlen) { + // No answer, try to resurrect + case 0: { + // Stop if there is no answer while we are in crypto mode (after sending NrAr) + if (bCrypto) { + // Failed during authentication + if (bAuthenticating) { + DbpString("Authentication failed!"); + return false; + } else { + // Failed reading a block, could be (read/write) locked, skip block and re-authenticate + if (blocknr == 1) { + // Write the low part of the key in memory + memcpy(tag.sectors[1],key+2,4); + } else if (blocknr == 2) { + // Write the high part of the key in memory + tag.sectors[2][0] = 0x00; + tag.sectors[2][1] = 0x00; + tag.sectors[2][2] = key[0]; + tag.sectors[2][3] = key[1]; + } else { + // Just put zero's in the memory (of the unreadable block) + memset(tag.sectors[blocknr],0x00,4); + } + blocknr++; + bCrypto = false; + } + } else { + *txlen = 5; + memcpy(tx,"\xc0",nbytes(*txlen)); + } + } break; + + // Received UID, crypto tag answer + case 32: { + if (!bCrypto) { + uint64_t ui64key = key[0] | ((uint64_t)key[1]) << 8 | ((uint64_t)key[2]) << 16 | ((uint64_t)key[3]) << 24 | ((uint64_t)key[4]) << 32 | ((uint64_t)key[5]) << 40; + uint32_t ui32uid = rx[0] | ((uint32_t)rx[1]) << 8 | ((uint32_t)rx[2]) << 16 | ((uint32_t)rx[3]) << 24; + cipher_state = _hitag2_init(rev64(ui64key), rev32(ui32uid), 0); + memset(tx,0x00,4); + memset(tx+4,0xff,4); + hitag2_cipher_transcrypt(&cipher_state,tx+4,4,0); + *txlen = 64; + bCrypto = true; + bAuthenticating = true; + } else { + // Check if we received answer tag (at) + if (bAuthenticating) { + bAuthenticating = false; + } else { + // Store the received block + memcpy(tag.sectors[blocknr],rx,4); + blocknr++; + } + if (blocknr > 7) { + DbpString("Read succesful!"); + bSuccessful = true; + return false; + } + *txlen = 10; + tx[0] = 0xc0 | (blocknr << 3) | ((blocknr^7) >> 2); + tx[1] = ((blocknr^7) << 6); + } + } break; + + // Unexpected response + default: { + Dbprintf("Uknown frame length: %d",rxlen); + return false; + } break; + } + + + if(bCrypto) { + // We have to return now to avoid double encryption + if (!bAuthenticating) { + hitag2_cipher_transcrypt(&cipher_state,tx,*txlen/8,*txlen%8); + } + } + + return true; +} + + +static bool hitag2_authenticate(byte_t* rx, const size_t rxlen, byte_t* tx, size_t* txlen) { + // Reset the transmission frame length + *txlen = 0; + + // Try to find out which command was send by selecting on length (in bits) + switch (rxlen) { + // No answer, try to resurrect + case 0: { + // Stop if there is no answer while we are in crypto mode (after sending NrAr) + if (bCrypto) { + DbpString("Authentication failed!"); + return false; + } + *txlen = 5; + memcpy(tx,"\xc0",nbytes(*txlen)); + } break; + + // Received UID, crypto tag answer + case 32: { + if (!bCrypto) { + *txlen = 64; + memcpy(tx,NrAr,8); + bCrypto = true; + } else { + DbpString("Authentication succesful!"); + // We are done... for now + return false; + } + } break; + + // Unexpected response + default: { + Dbprintf("Uknown frame length: %d",rxlen); + return false; + } break; + } + + return true; +} + + +static bool hitag2_test_auth_attempts(byte_t* rx, const size_t rxlen, byte_t* tx, size_t* txlen) { + + // Reset the transmission frame length + *txlen = 0; + + // Try to find out which command was send by selecting on length (in bits) + switch (rxlen) { + // No answer, try to resurrect + case 0: { + // Stop if there is no answer while we are in crypto mode (after sending NrAr) + if (bCrypto) { + Dbprintf("auth: %02x%02x%02x%02x%02x%02x%02x%02x Failed, removed entry!",NrAr[0],NrAr[1],NrAr[2],NrAr[3],NrAr[4],NrAr[5],NrAr[6],NrAr[7]); + + // Removing failed entry from authentiations table + memcpy(auth_table+auth_table_pos,auth_table+auth_table_pos+8,8); + auth_table_len -= 8; + + // Return if we reached the end of the authentications table + bCrypto = false; + if (auth_table_pos == auth_table_len) { + return false; + } + + // Copy the next authentication attempt in row (at the same position, b/c we removed last failed entry) + memcpy(NrAr,auth_table+auth_table_pos,8); + } + *txlen = 5; + memcpy(tx,"\xc0",nbytes(*txlen)); + } break; + + // Received UID, crypto tag answer, or read block response + case 32: { + if (!bCrypto) { + *txlen = 64; + memcpy(tx,NrAr,8); + bCrypto = true; + } else { + Dbprintf("auth: %02x%02x%02x%02x%02x%02x%02x%02x OK",NrAr[0],NrAr[1],NrAr[2],NrAr[3],NrAr[4],NrAr[5],NrAr[6],NrAr[7]); + bCrypto = false; + if ((auth_table_pos+8) == auth_table_len) { + return false; + } + auth_table_pos += 8; + memcpy(NrAr,auth_table+auth_table_pos,8); + } + } break; + + default: { + Dbprintf("Uknown frame length: %d",rxlen); + return false; + } break; + } + + return true; +} + + +void SnoopHitag(uint32_t type) { + int frame_count; + int response; + int overflow; + bool rising_edge; + bool reader_frame; + int lastbit; + bool bSkip; + int tag_sof; + byte_t rx[HITAG_FRAME_LEN]; + size_t rxlen=0; + + FpgaDownloadAndGo(FPGA_BITSTREAM_LF); + + // Clean up trace and prepare it for storing frames + set_tracing(TRUE); + clear_trace(); + + auth_table_len = 0; + auth_table_pos = 0; + + BigBuf_free(); + auth_table = (byte_t *)BigBuf_malloc(AUTH_TABLE_LENGTH); + memset(auth_table, 0x00, AUTH_TABLE_LENGTH); + + DbpString("Starting Hitag2 snoop"); + LED_D_ON(); + + // Set up eavesdropping mode, frequency divisor which will drive the FPGA + // and analog mux selection. + FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_EDGE_DETECT | FPGA_LF_EDGE_DETECT_TOGGLE_MODE); + FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 95); //125Khz + SetAdcMuxFor(GPIO_MUXSEL_LOPKD); + RELAY_OFF(); + + // Configure output pin that is connected to the FPGA (for modulating) + AT91C_BASE_PIOA->PIO_OER = GPIO_SSC_DOUT; + AT91C_BASE_PIOA->PIO_PER = GPIO_SSC_DOUT; + + // Disable modulation, we are going to eavesdrop, not modulate ;) + LOW(GPIO_SSC_DOUT); + + // Enable Peripheral Clock for TIMER_CLOCK1, used to capture edges of the reader frames + AT91C_BASE_PMC->PMC_PCER = (1 << AT91C_ID_TC1); + AT91C_BASE_PIOA->PIO_BSR = GPIO_SSC_FRAME; + + // Disable timer during configuration + AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKDIS; + + // Capture mode, defaul timer source = MCK/2 (TIMER_CLOCK1), TIOA is external trigger, + // external trigger rising edge, load RA on rising edge of TIOA. + uint32_t t1_channel_mode = AT91C_TC_CLKS_TIMER_DIV1_CLOCK | AT91C_TC_ETRGEDG_BOTH | AT91C_TC_ABETRG | AT91C_TC_LDRA_BOTH; + AT91C_BASE_TC1->TC_CMR = t1_channel_mode; + + // Enable and reset counter + AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKEN | AT91C_TC_SWTRG; + + // Reset the received frame, frame count and timing info + memset(rx,0x00,sizeof(rx)); + frame_count = 0; + response = 0; + overflow = 0; + reader_frame = false; + lastbit = 1; + bSkip = true; + tag_sof = 4; + + while(!BUTTON_PRESS()) { + // Watchdog hit + WDT_HIT(); + + // Receive frame, watch for at most T0*EOF periods + while (AT91C_BASE_TC1->TC_CV < T0*HITAG_T_EOF) { + // Check if rising edge in modulation is detected + if(AT91C_BASE_TC1->TC_SR & AT91C_TC_LDRAS) { + // Retrieve the new timing values + int ra = (AT91C_BASE_TC1->TC_RA/T0); + + // Find out if we are dealing with a rising or falling edge + rising_edge = (AT91C_BASE_PIOA->PIO_PDSR & GPIO_SSC_FRAME) > 0; + + // Shorter periods will only happen with reader frames + if (!reader_frame && rising_edge && ra < HITAG_T_TAG_CAPTURE_ONE_HALF) { + // Switch from tag to reader capture + LED_C_OFF(); + reader_frame = true; + memset(rx,0x00,sizeof(rx)); + rxlen = 0; + } + + // Only handle if reader frame and rising edge, or tag frame and falling edge + if (reader_frame != rising_edge) { + overflow += ra; + continue; + } + + // Add the buffered timing values of earlier captured edges which were skipped + ra += overflow; + overflow = 0; + + if (reader_frame) { + LED_B_ON(); + // Capture reader frame + if(ra >= HITAG_T_STOP) { + if (rxlen != 0) { + //DbpString("wierd0?"); + } + // Capture the T0 periods that have passed since last communication or field drop (reset) + response = (ra - HITAG_T_LOW); + } else if(ra >= HITAG_T_1_MIN ) { + // '1' bit + rx[rxlen / 8] |= 1 << (7-(rxlen%8)); + rxlen++; + } else if(ra >= HITAG_T_0_MIN) { + // '0' bit + rx[rxlen / 8] |= 0 << (7-(rxlen%8)); + rxlen++; + } else { + // Ignore wierd value, is to small to mean anything + } + } else { + LED_C_ON(); + // Capture tag frame (manchester decoding using only falling edges) + if(ra >= HITAG_T_EOF) { + if (rxlen != 0) { + //DbpString("wierd1?"); + } + // Capture the T0 periods that have passed since last communication or field drop (reset) + // We always recieve a 'one' first, which has the falling edge after a half period |-_| + response = ra-HITAG_T_TAG_HALF_PERIOD; + } else if(ra >= HITAG_T_TAG_CAPTURE_FOUR_HALF) { + // Manchester coding example |-_|_-|-_| (101) + rx[rxlen / 8] |= 0 << (7-(rxlen%8)); + rxlen++; + rx[rxlen / 8] |= 1 << (7-(rxlen%8)); + rxlen++; + } else if(ra >= HITAG_T_TAG_CAPTURE_THREE_HALF) { + // Manchester coding example |_-|...|_-|-_| (0...01) + rx[rxlen / 8] |= 0 << (7-(rxlen%8)); + rxlen++; + // We have to skip this half period at start and add the 'one' the second time + if (!bSkip) { + rx[rxlen / 8] |= 1 << (7-(rxlen%8)); + rxlen++; + } + lastbit = !lastbit; + bSkip = !bSkip; + } else if(ra >= HITAG_T_TAG_CAPTURE_TWO_HALF) { + // Manchester coding example |_-|_-| (00) or |-_|-_| (11) + if (tag_sof) { + // Ignore bits that are transmitted during SOF + tag_sof--; + } else { + // bit is same as last bit + rx[rxlen / 8] |= lastbit << (7-(rxlen%8)); + rxlen++; + } + } else { + // Ignore wierd value, is to small to mean anything + } + } + } + } + + // Check if frame was captured + if(rxlen > 0) { + frame_count++; + if (!LogTraceHitag(rx,rxlen,response,0,reader_frame)) { + DbpString("Trace full"); + break; + } + + // Check if we recognize a valid authentication attempt + if (nbytes(rxlen) == 8) { + // Store the authentication attempt + if (auth_table_len < (AUTH_TABLE_LENGTH-8)) { + memcpy(auth_table+auth_table_len,rx,8); + auth_table_len += 8; + } + } + + // Reset the received frame and response timing info + memset(rx,0x00,sizeof(rx)); + response = 0; + reader_frame = false; + lastbit = 1; + bSkip = true; + tag_sof = 4; + overflow = 0; + + LED_B_OFF(); + LED_C_OFF(); + } else { + // Save the timer overflow, will be 0 when frame was received + overflow += (AT91C_BASE_TC1->TC_CV/T0); + } + // Reset the frame length + rxlen = 0; + // Reset the timer to restart while-loop that receives frames + AT91C_BASE_TC1->TC_CCR = AT91C_TC_SWTRG; + } + LED_A_ON(); + LED_B_OFF(); + LED_C_OFF(); + LED_D_OFF(); + AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKDIS; + AT91C_BASE_TC0->TC_CCR = AT91C_TC_CLKDIS; + FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF); + LED_A_OFF(); + +// Dbprintf("frame received: %d",frame_count); +// Dbprintf("Authentication Attempts: %d",(auth_table_len/8)); +// DbpString("All done"); +} + +void SimulateHitagTag(bool tag_mem_supplied, byte_t* data) { + int frame_count; + int response; + int overflow; + byte_t rx[HITAG_FRAME_LEN]; + size_t rxlen=0; + byte_t tx[HITAG_FRAME_LEN]; + size_t txlen=0; + bool bQuitTraceFull = false; + bQuiet = false; + + FpgaDownloadAndGo(FPGA_BITSTREAM_LF); + + // Clean up trace and prepare it for storing frames + set_tracing(TRUE); + clear_trace(); + + auth_table_len = 0; + auth_table_pos = 0; + byte_t* auth_table; + BigBuf_free(); + auth_table = (byte_t *)BigBuf_malloc(AUTH_TABLE_LENGTH); + memset(auth_table, 0x00, AUTH_TABLE_LENGTH); + + DbpString("Starting Hitag2 simulation"); + LED_D_ON(); + hitag2_init(); + + if (tag_mem_supplied) { + DbpString("Loading hitag2 memory..."); + memcpy((byte_t*)tag.sectors,data,48); + } + + uint32_t block = 0; + for (size_t i=0; i<12; i++) { + for (size_t j=0; j<4; j++) { + block <<= 8; + block |= tag.sectors[i][j]; + } + Dbprintf("| %d | %08x |",i,block); + } + + // Set up simulator mode, frequency divisor which will drive the FPGA + // and analog mux selection. + FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_EDGE_DETECT | FPGA_LF_EDGE_DETECT_READER_FIELD); + FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 95); //125Khz + SetAdcMuxFor(GPIO_MUXSEL_LOPKD); + RELAY_OFF(); + + // Configure output pin that is connected to the FPGA (for modulating) + AT91C_BASE_PIOA->PIO_OER = GPIO_SSC_DOUT; + AT91C_BASE_PIOA->PIO_PER = GPIO_SSC_DOUT; + + // Disable modulation at default, which means release resistance + LOW(GPIO_SSC_DOUT); + + // Enable Peripheral Clock for TIMER_CLOCK0, used to measure exact timing before answering + AT91C_BASE_PMC->PMC_PCER = (1 << AT91C_ID_TC0); + + // Enable Peripheral Clock for TIMER_CLOCK1, used to capture edges of the reader frames + AT91C_BASE_PMC->PMC_PCER = (1 << AT91C_ID_TC1); + AT91C_BASE_PIOA->PIO_BSR = GPIO_SSC_FRAME; + + // Disable timer during configuration + AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKDIS; + + // Capture mode, default timer source = MCK/2 (TIMER_CLOCK1), TIOA is external trigger, + // external trigger rising edge, load RA on rising edge of TIOA. + AT91C_BASE_TC1->TC_CMR = AT91C_TC_CLKS_TIMER_DIV1_CLOCK | AT91C_TC_ETRGEDG_RISING | AT91C_TC_ABETRG | AT91C_TC_LDRA_RISING; + + // Reset the received frame, frame count and timing info + memset(rx,0x00,sizeof(rx)); + frame_count = 0; + response = 0; + overflow = 0; + + // Enable and reset counter + AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKEN | AT91C_TC_SWTRG; + + while(!BUTTON_PRESS()) { + // Watchdog hit + WDT_HIT(); + + // Receive frame, watch for at most T0*EOF periods + while (AT91C_BASE_TC1->TC_CV < T0*HITAG_T_EOF) { + // Check if rising edge in modulation is detected + if(AT91C_BASE_TC1->TC_SR & AT91C_TC_LDRAS) { + // Retrieve the new timing values + int ra = (AT91C_BASE_TC1->TC_RA/T0) + overflow; + overflow = 0; + + // Reset timer every frame, we have to capture the last edge for timing + AT91C_BASE_TC0->TC_CCR = AT91C_TC_CLKEN | AT91C_TC_SWTRG; + + LED_B_ON(); + + // Capture reader frame + if(ra >= HITAG_T_STOP) { + if (rxlen != 0) { + //DbpString("wierd0?"); + } + // Capture the T0 periods that have passed since last communication or field drop (reset) + response = (ra - HITAG_T_LOW); + } else if(ra >= HITAG_T_1_MIN ) { + // '1' bit + rx[rxlen / 8] |= 1 << (7-(rxlen%8)); + rxlen++; + } else if(ra >= HITAG_T_0_MIN) { + // '0' bit + rx[rxlen / 8] |= 0 << (7-(rxlen%8)); + rxlen++; + } else { + // Ignore wierd value, is to small to mean anything + } + } + } + + // Check if frame was captured + if(rxlen > 4) { + frame_count++; + if (!bQuiet) { + if (!LogTraceHitag(rx,rxlen,response,0,true)) { + DbpString("Trace full"); + if (bQuitTraceFull) { + break; + } else { + bQuiet = true; + } + } + } + + // Disable timer 1 with external trigger to avoid triggers during our own modulation + AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKDIS; + + // Process the incoming frame (rx) and prepare the outgoing frame (tx) + hitag2_handle_reader_command(rx,rxlen,tx,&txlen); + + // Wait for HITAG_T_WAIT_1 carrier periods after the last reader bit, + // not that since the clock counts since the rising edge, but T_Wait1 is + // with respect to the falling edge, we need to wait actually (T_Wait1 - T_Low) + // periods. The gap time T_Low varies (4..10). All timer values are in + // terms of T0 units + while(AT91C_BASE_TC0->TC_CV < T0*(HITAG_T_WAIT_1-HITAG_T_LOW)); + + // Send and store the tag answer (if there is any) + if (txlen) { + // Transmit the tag frame + hitag_send_frame(tx,txlen); + // Store the frame in the trace + if (!bQuiet) { + if (!LogTraceHitag(tx,txlen,0,0,false)) { + DbpString("Trace full"); + if (bQuitTraceFull) { + break; + } else { + bQuiet = true; + } + } + } + } + + // Reset the received frame and response timing info + memset(rx,0x00,sizeof(rx)); + response = 0; + + // Enable and reset external trigger in timer for capturing future frames + AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKEN | AT91C_TC_SWTRG; + LED_B_OFF(); + } + // Reset the frame length + rxlen = 0; + // Save the timer overflow, will be 0 when frame was received + overflow += (AT91C_BASE_TC1->TC_CV/T0); + // Reset the timer to restart while-loop that receives frames + AT91C_BASE_TC1->TC_CCR = AT91C_TC_SWTRG; + } + LED_B_OFF(); + LED_D_OFF(); + AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKDIS; + AT91C_BASE_TC0->TC_CCR = AT91C_TC_CLKDIS; + FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF); + + DbpString("Sim Stopped"); + +} + +void ReaderHitag(hitag_function htf, hitag_data* htd) { + int frame_count; + int response; + byte_t rx[HITAG_FRAME_LEN]; + size_t rxlen=0; + byte_t txbuf[HITAG_FRAME_LEN]; + byte_t* tx = txbuf; + size_t txlen=0; + int lastbit; + bool bSkip; + int reset_sof; + int tag_sof; + int t_wait = HITAG_T_WAIT_MAX; + bool bStop; + bool bQuitTraceFull = false; + + FpgaDownloadAndGo(FPGA_BITSTREAM_LF); + // Reset the return status + bSuccessful = false; + + // Clean up trace and prepare it for storing frames + set_tracing(TRUE); + clear_trace(); + + DbpString("Starting Hitag reader family"); + + // Check configuration + switch(htf) { + case RHT2F_PASSWORD: { + Dbprintf("List identifier in password mode"); + memcpy(password,htd->pwd.password,4); + blocknr = 0; + bQuitTraceFull = false; + bQuiet = false; + bPwd = false; + } break; + + case RHT2F_AUTHENTICATE: { + DbpString("Authenticating using nr,ar pair:"); + memcpy(NrAr,htd->auth.NrAr,8); + Dbhexdump(8,NrAr,false); + bQuiet = false; + bCrypto = false; + bAuthenticating = false; + bQuitTraceFull = true; + } break; + + case RHT2F_CRYPTO: { + DbpString("Authenticating using key:"); + memcpy(key,htd->crypto.key,4); //HACK; 4 or 6?? I read both in the code. + Dbhexdump(6,key,false); + blocknr = 0; + bQuiet = false; + bCrypto = false; + bAuthenticating = false; + bQuitTraceFull = true; + } break; + + case RHT2F_TEST_AUTH_ATTEMPTS: { + Dbprintf("Testing %d authentication attempts",(auth_table_len/8)); + auth_table_pos = 0; + memcpy(NrAr, auth_table, 8); + bQuitTraceFull = false; + bQuiet = false; + bCrypto = false; + } break; + + default: { + Dbprintf("Error, unknown function: %d",htf); + return; + } break; + } + + LED_D_ON(); + hitag2_init(); + + // Configure output and enable pin that is connected to the FPGA (for modulating) + AT91C_BASE_PIOA->PIO_OER = GPIO_SSC_DOUT; + AT91C_BASE_PIOA->PIO_PER = GPIO_SSC_DOUT; + + // Set fpga in edge detect with reader field, we can modulate as reader now + FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_EDGE_DETECT | FPGA_LF_EDGE_DETECT_READER_FIELD); + + // Set Frequency divisor which will drive the FPGA and analog mux selection + FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 95); //125Khz + SetAdcMuxFor(GPIO_MUXSEL_LOPKD); + RELAY_OFF(); + + // Disable modulation at default, which means enable the field + LOW(GPIO_SSC_DOUT); + + // Give it a bit of time for the resonant antenna to settle. + SpinDelay(30); + + // Enable Peripheral Clock for TIMER_CLOCK0, used to measure exact timing before answering + AT91C_BASE_PMC->PMC_PCER = (1 << AT91C_ID_TC0); + + // Enable Peripheral Clock for TIMER_CLOCK1, used to capture edges of the tag frames + AT91C_BASE_PMC->PMC_PCER = (1 << AT91C_ID_TC1); + AT91C_BASE_PIOA->PIO_BSR = GPIO_SSC_FRAME; + + // Disable timer during configuration + AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKDIS; + + // Capture mode, defaul timer source = MCK/2 (TIMER_CLOCK1), TIOA is external trigger, + // external trigger rising edge, load RA on falling edge of TIOA. + AT91C_BASE_TC1->TC_CMR = AT91C_TC_CLKS_TIMER_DIV1_CLOCK | AT91C_TC_ETRGEDG_FALLING | AT91C_TC_ABETRG | AT91C_TC_LDRA_FALLING; + + // Enable and reset counters + AT91C_BASE_TC0->TC_CCR = AT91C_TC_CLKEN | AT91C_TC_SWTRG; + AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKEN | AT91C_TC_SWTRG; + + // Reset the received frame, frame count and timing info + frame_count = 0; + response = 0; + lastbit = 1; + bStop = false; + + // Tag specific configuration settings (sof, timings, etc.) + if (htf < 10){ + // hitagS settings + reset_sof = 1; + t_wait = 200; + DbpString("Configured for hitagS reader"); + } else if (htf < 20) { + // hitag1 settings + reset_sof = 1; + t_wait = 200; + DbpString("Configured for hitag1 reader"); + } else if (htf < 30) { + // hitag2 settings + reset_sof = 4; + t_wait = HITAG_T_WAIT_2; + DbpString("Configured for hitag2 reader"); + } else { + Dbprintf("Error, unknown hitag reader type: %d",htf); + return; + } + + while(!bStop && !BUTTON_PRESS()) { + // Watchdog hit + WDT_HIT(); + + // Check if frame was captured and store it + if(rxlen > 0) { + frame_count++; + if (!bQuiet) { + if (!LogTraceHitag(rx,rxlen,response,0,false)) { + DbpString("Trace full"); + if (bQuitTraceFull) { + break; + } else { + bQuiet = true; + } + } + } + } + + // By default reset the transmission buffer + tx = txbuf; + switch(htf) { + case RHT2F_PASSWORD: { + bStop = !hitag2_password(rx,rxlen,tx,&txlen); + } break; + case RHT2F_AUTHENTICATE: { + bStop = !hitag2_authenticate(rx,rxlen,tx,&txlen); + } break; + case RHT2F_CRYPTO: { + bStop = !hitag2_crypto(rx,rxlen,tx,&txlen); + } break; + case RHT2F_TEST_AUTH_ATTEMPTS: { + bStop = !hitag2_test_auth_attempts(rx,rxlen,tx,&txlen); + } break; + default: { + Dbprintf("Error, unknown function: %d",htf); + return; + } break; + } + + // Send and store the reader command + // Disable timer 1 with external trigger to avoid triggers during our own modulation + AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKDIS; + + // Wait for HITAG_T_WAIT_2 carrier periods after the last tag bit before transmitting, + // Since the clock counts since the last falling edge, a 'one' means that the + // falling edge occured halfway the period. with respect to this falling edge, + // we need to wait (T_Wait2 + half_tag_period) when the last was a 'one'. + // All timer values are in terms of T0 units + while(AT91C_BASE_TC0->TC_CV < T0*(t_wait+(HITAG_T_TAG_HALF_PERIOD*lastbit))); + + // Transmit the reader frame + hitag_reader_send_frame(tx,txlen); + + // Enable and reset external trigger in timer for capturing future frames + AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKEN | AT91C_TC_SWTRG; + + // Add transmitted frame to total count + if(txlen > 0) { + frame_count++; + if (!bQuiet) { + // Store the frame in the trace + if (!LogTraceHitag(tx,txlen,HITAG_T_WAIT_2,0,true)) { + if (bQuitTraceFull) { + break; + } else { + bQuiet = true; + } + } + } + } + + // Reset values for receiving frames + memset(rx,0x00,sizeof(rx)); + rxlen = 0; + lastbit = 1; + bSkip = true; + tag_sof = reset_sof; + response = 0; + + // Receive frame, watch for at most T0*EOF periods + while (AT91C_BASE_TC1->TC_CV < T0*HITAG_T_WAIT_MAX) { + // Check if falling edge in tag modulation is detected + if(AT91C_BASE_TC1->TC_SR & AT91C_TC_LDRAS) { + // Retrieve the new timing values + int ra = (AT91C_BASE_TC1->TC_RA/T0); + + // Reset timer every frame, we have to capture the last edge for timing + AT91C_BASE_TC0->TC_CCR = AT91C_TC_SWTRG; + + LED_B_ON(); + + // Capture tag frame (manchester decoding using only falling edges) + if(ra >= HITAG_T_EOF) { + if (rxlen != 0) { + //DbpString("wierd1?"); + } + // Capture the T0 periods that have passed since last communication or field drop (reset) + // We always recieve a 'one' first, which has the falling edge after a half period |-_| + response = ra-HITAG_T_TAG_HALF_PERIOD; + } else if(ra >= HITAG_T_TAG_CAPTURE_FOUR_HALF) { + // Manchester coding example |-_|_-|-_| (101) + rx[rxlen / 8] |= 0 << (7-(rxlen%8)); + rxlen++; + rx[rxlen / 8] |= 1 << (7-(rxlen%8)); + rxlen++; + } else if(ra >= HITAG_T_TAG_CAPTURE_THREE_HALF) { + // Manchester coding example |_-|...|_-|-_| (0...01) + rx[rxlen / 8] |= 0 << (7-(rxlen%8)); + rxlen++; + // We have to skip this half period at start and add the 'one' the second time + if (!bSkip) { + rx[rxlen / 8] |= 1 << (7-(rxlen%8)); + rxlen++; + } + lastbit = !lastbit; + bSkip = !bSkip; + } else if(ra >= HITAG_T_TAG_CAPTURE_TWO_HALF) { + // Manchester coding example |_-|_-| (00) or |-_|-_| (11) + if (tag_sof) { + // Ignore bits that are transmitted during SOF + tag_sof--; + } else { + // bit is same as last bit + rx[rxlen / 8] |= lastbit << (7-(rxlen%8)); + rxlen++; + } + } else { + // Ignore wierd value, is to small to mean anything + } + } + + // We can break this loop if we received the last bit from a frame + if (AT91C_BASE_TC1->TC_CV > T0*HITAG_T_EOF) { + if (rxlen>0) break; + } + } + } + LED_B_OFF(); + LED_D_OFF(); + AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKDIS; + AT91C_BASE_TC0->TC_CCR = AT91C_TC_CLKDIS; + FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF); + Dbprintf("frame received: %d",frame_count); + DbpString("All done"); + cmd_send(CMD_ACK,bSuccessful,0,0,(byte_t*)tag.sectors,48); +}