fixed ISO 14443A anticollision

git-svn-id: https://svn.gnumonks.org/trunk/librfid@1988 e0336214-984f-0b4b-a45f-81c69e1f0ede

diff --git a/src/rfid_asic_rc632.c b/src/rfid_asic_rc632.c
index 0d6824c..0560d09 100644 (file)
--- a/src/rfid_asic_rc632.c
+++ b/src/rfid_asic_rc632.c
@@ -875,7 +875,7 @@ rc632_iso14443a_transceive_acf(struct rfid_asic_handle *handle,
        int ret;
        u_int8_t rx_buf[64];
        u_int8_t rx_len = sizeof(rx_buf);
-       u_int8_t rx_align = 0, tx_last_bits, tx_bytes;
+       u_int8_t rx_align = 0, tx_last_bits, tx_bytes, tx_bytes_total;
        u_int8_t boc;
        u_int8_t error_flag;
        *bit_of_col = ISO14443A_BITOFCOL_NONE;
@@ -899,14 +899,14 @@ rc632_iso14443a_transceive_acf(struct rfid_asic_handle *handle,
        if (ret < 0)
                return ret;
 
-       tx_last_bits = acf->nvb & 0x0f; /* lower nibble indicates bits */
-       tx_bytes = acf->nvb >> 4;
+       tx_last_bits = acf->nvb & 0x07; /* lower nibble indicates bits */
+       tx_bytes = ( acf->nvb >> 4 ) & 0x07;
        if (tx_last_bits) {
-               tx_bytes++;
-               rx_align = (tx_last_bits+1) % 8;/* rx frame complements tx */
+               tx_bytes_total = tx_bytes+1;
+               rx_align = tx_last_bits & 0x07; /* rx frame complements tx */
        }
-
-       //rx_align = 8 - tx_last_bits;/* rx frame complements tx */
+       else
+               tx_bytes_total = tx_bytes;
 
        /* set RxAlign and TxLastBits*/
        ret = rc632_reg_write(handle, RC632_REG_BIT_FRAMING,
@@ -914,7 +914,7 @@ rc632_iso14443a_transceive_acf(struct rfid_asic_handle *handle,
        if (ret < 0)
                return ret;
 
-       ret = rc632_transceive(handle, (u_int8_t *)acf, tx_bytes,
+       ret = rc632_transceive(handle, (u_int8_t *)acf, tx_bytes_total,
                                rx_buf, &rx_len, 0x32, 0);
        if (ret < 0)
                return ret;
@@ -923,8 +923,10 @@ rc632_iso14443a_transceive_acf(struct rfid_asic_handle *handle,
        acf->uid_bits[tx_bytes-2] = (
                  (acf->uid_bits[tx_bytes-2] & (0xff >> (8-tx_last_bits)))
                | rx_buf[0]);
+       
        /* copy the rest */
-       memcpy(&acf->uid_bits[tx_bytes+1-2], &rx_buf[1], rx_len-1);
+       if(rx_len)
+           memcpy(&acf->uid_bits[tx_bytes-1], &rx_buf[1], rx_len-1);
 
        /* determine whether there was a collission */
        ret = rc632_reg_read(handle, RC632_REG_ERROR_FLAG, &error_flag);

diff --git a/src/rfid_layer2_iso14443a.c b/src/rfid_layer2_iso14443a.c
index 4716018..2c4cb1e 100644 (file)
--- 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;