diff options
Diffstat (limited to 'src/rfid_layer2_iso14443a.c')
| -rw-r--r-- | src/rfid_layer2_iso14443a.c | 52 |
1 files changed, 38 insertions, 14 deletions
diff --git a/src/rfid_layer2_iso14443a.c b/src/rfid_layer2_iso14443a.c index 4716018..2c4cb1e 100644 --- a/src/rfid_layer2_iso14443a.c +++ b/src/rfid_layer2_iso14443a.c @@ -23,6 +23,8 @@ #include <unistd.h> #include <string.h> #include <errno.h> + +// #define DEBUG_LIBRFID #include <librfid/rfid.h> #include <librfid/rfid_layer2.h> @@ -32,6 +34,8 @@ #define TIMEOUT 1236 +unsigned long randctx[4]={0x22d4a017,0x773a1f44,0xc39e1460,0x9cde8801}; + /* Transceive a 7-bit short frame */ int iso14443a_transceive_sf(struct rfid_layer2_handle *handle, @@ -80,20 +84,38 @@ iso14443a_code_nvb_bits(unsigned char *nvb, unsigned int bits) return 0; } +int random_bit(void) +{ + unsigned long e; + + e = randctx[0]; + randctx[0]=randctx[1]; + randctx[1]=(randctx[2]<<19) + (randctx[2]>>13) + randctx[3]; + randctx[2]=randctx[3] ^ randctx[0]; + randctx[3]=e+randctx[1]; + + return randctx[1]&1; +} + /* first bit is '1', second bit '2' */ static void -set_bit_in_field(unsigned char *bitfield, unsigned int bit) +rnd_toggle_bit_in_field(unsigned char *bitfield, unsigned int size, unsigned int bit) { - unsigned int byte_count = bit / 8; - unsigned int bit_count = bit % 8; - - DEBUGP("bitfield=%p, byte_count=%u, bit_count=%u\n", - bitfield, byte_count, bit_count); - DEBUGP("%p = 0x%02x\n", (bitfield+byte_count), *(bitfield+byte_count)); - *(bitfield+byte_count) |= 1 << (bit_count-1); - DEBUGP("%p = 0x%02x\n", (bitfield+byte_count), *(bitfield+byte_count)); + unsigned int byte,rnd; + + if(bit && (bit <= (size*8)) ) + { + rnd=random_bit(); + + DEBUGP("xor'ing bit %u with %u\n",bit,rnd); + bit--; + byte=bit/8; + bit=rnd<<(bit%8); + bitfield[byte] ^= bit; + } } + static int iso14443a_anticol(struct rfid_layer2_handle *handle) { @@ -122,7 +144,7 @@ iso14443a_anticol(struct rfid_layer2_handle *handle) return ret; } h->state = ISO14443A_STATE_ATQA_RCVD; - + DEBUGP("ATQA: 0x%02x 0x%02x\n", *aqptr, *(aqptr+1)); if (!atqa->bf_anticol) { @@ -150,18 +172,20 @@ cascade: ret = iso14443a_transceive_acf(handle, &acf, &bit_of_col); if (ret < 0) return ret; - DEBUGP("bit_of_col = %u\n", bit_of_col); while (bit_of_col != ISO14443A_BITOFCOL_NONE) { - set_bit_in_field(&acf.uid_bits[0], bit_of_col-16); + DEBUGP("collision at pos %u\n", bit_of_col); + iso14443a_code_nvb_bits(&acf.nvb, bit_of_col); + rnd_toggle_bit_in_field(acf.uid_bits, sizeof(acf.uid_bits), bit_of_col); + DEBUGP("acf: nvb=0x%02X uid_bits=%s\n",acf.nvb,rfid_hexdump(acf.uid_bits,sizeof(acf.uid_bits))); ret = iso14443a_transceive_acf(handle, &acf, &bit_of_col); - DEBUGP("bit_of_col = %u\n", bit_of_col); if (ret < 0) return ret; } iso14443a_code_nvb_bits(&acf.nvb, 7*8); + ret = iso14443a_transceive(handle, RFID_14443A_FRAME_REGULAR, (unsigned char *)&acf, 7, (unsigned char *) &sak, &rx_len, @@ -325,7 +349,7 @@ iso14443a_init(struct rfid_reader_handle *rh) return NULL; memset(h, 0, sizeof(*h)); - + h->l2 = &rfid_layer2_iso14443a; h->rh = rh; h->priv.iso14443a.state = ISO14443A_STATE_NONE; |