/*
* Get a pointer to the next record in the provided TLV sequence.
* | 0x03 | 0x02 | 0xbe | 0xef | 0x00 | 0x00 | 0xfe |
* First call ---' | |
* Second call -------------------------------' |
* Third call --------------------------------------'
* Fourth call NULL
*/
uint8_t *
tlv_next (uint8_t *stream)
{
uint8_t *res = NULL;
if (stream[0] != TLV_TERMINATOR)
res = stream + tlv_record_length (stream, NULL, NULL);
return res;
}
/*
* Full-length of all TLV fields.
*/
size_t
tlv_sequence_length (uint8_t *stream)
{
size_t res = 0;
do {
res += tlv_record_length (stream, NULL, NULL);
} while ((stream = tlv_next (stream)));
return res;
}
/*
* Decode TLV from data stream.
*/
uint8_t *
tlv_decode (const uint8_t *istream, uint8_t *type, uint16_t *size)
{
size_t fls = 0;
size_t fvs = 0;
uint8_t *res = NULL;
if (type)
*type = istream[0];
tlv_record_length (istream, &fls, &fvs);
if (size) {
*size = fvs;
}
if ((res = malloc (fvs))) {
memcpy (res, istream + 1 + fls, fvs);
}
return res;
}
int
mifare_classic_read_ndef(MifareTag tag, char * buffer, char *max_size)
{
int error = EXIT_SUCCESS;
Mad mad;
// NFCForum card has a MAD, load it.
if (0 == mifare_classic_connect (tag)) {
} else {
return -2;
}
if ((mad = mad_read (tag))) {
// Dump the NFCForum application using MAD information
ssize_t len;
if ((len = mifare_application_read (tag, mad, mad_nfcforum_aid, buffer, max_size, mifare_classic_nfcforum_public_key_a, MFC_KEY_A)) != -1) {
uint8_t tlv_type;
uint16_t tlv_data_len;
uint8_t * tlv_data;
uint8_t * pbuffer = buffer;
uint8_t found = false;
while (!found)
{
tlv_data = tlv_decode (pbuffer, &tlv_type, &tlv_data_len);
switch (tlv_type) {
case 0x00:
printf ("NFC Forum application contains a \"NULL TLV\", Skipping...\n"); // According to [ANNFC1K4K], we skip this Tag to read further TLV blocks.
pbuffer += tlv_record_length(pbuffer, NULL, NULL);
if (pbuffer >= buffer + sizeof(buffer)) {
error= -3;
found = true;
}
break;
case 0x03:
printf ("NFC Forum application contains a \"NDEF Message TLV\".\n");
found = true;
error = tlv_data_len;
memcpy(buffer,tlv_data,tlv_data_len);
break;
case 0xFD:
printf ("NFC Forum application contains a \"Proprietary TLV\", Skipping...\n"); // According to [ANNFC1K4K], we can skip this TLV to read further TLV blocks.
pbuffer += tlv_record_length(pbuffer, NULL, NULL);
if (pbuffer >= buffer + sizeof(buffer)) {
error= -4;
found = true;
}
break;
case 0xFE:
printf ("NFC Forum application contains a \"Terminator TLV\", no available data.\n");
error= -5;
found = true;
break;
default:
printf ("NFC Forum application contains an invalid TLV.\n");
error= -6;
found = true;
}
}
} else {
printf ("No NFC Forum application.\n");
error= -7;
}
} else {
printf ("No MAD detected.\n");
}
vPortFree (mad);
return error;
}
