Fix issues for NTAG21x tags

- Change default tag from NTAG_213 to NTAG_UNKNOWN so unknown tags can
  be detected.  ntag_get_info() MUST be called after connect;
- Fix reuse function which used to reset all tag info;
- Introduce ntag21x error reporting through freefare_error(3);

HACKING.md

@@ -37,6 +37,8 @@ that you don't have to care about indentation anymore. For more details, please
 read the [style(9) man page from FreeBSD's
 website](http://www.freebsd.org/cgi/man.cgi?query=style).
 
+For style correction install package `astyle`. Then run `make style`.
+
 ## Write tests
 
 I already told you cutter is lovely, so you really should use it!  If you want

examples/mifare-desfire-ev1-configure-random-uid.c

@@ -153,8 +153,8 @@ main(int argc, char *argv[])
 		    }
 		}
 		break;
-	    case 4: // Random UID
+	    case 4: { // Random UID
-	    {} // Compilation fails if label is directly followed by the declaration rather than a statement
+	    } // Compilation fails if label is directly followed by the declaration rather than a statement
 	    MifareDESFireKey key_picc = mifare_desfire_des_key_new_with_version(key_data_picc);
 	    res = mifare_desfire_authenticate(tags[i], 0, key_picc);
 	    if (res < 0) {

libfreefare/CMakeLists.txt

@@ -13,6 +13,7 @@ set(LIBRARY_SOURCES
 		mifare_key_deriver
 		mifare_ultralight
 		ntag21x
+		ntag21x_error
 		tlv
 		../contrib/libutil/hexdump
 		)

libfreefare/Makefile.am

@@ -16,6 +16,7 @@ libfreefare_la_SOURCES = felica.c \
 			 mad.c \
 			 mifare_application.c \
 			 ntag21x.c \
+			 ntag21x_error.c \
 			 tlv.c
 libfreefare_la_LIBADD =
 

libfreefare/freefare.c

@@ -225,6 +225,8 @@ freefare_strerror(FreefareTag tag)
 	    } else if (MIFARE_DESFIRE(tag)->last_picc_error) {
 		p = mifare_desfire_error_lookup(MIFARE_DESFIRE(tag)->last_picc_error);
 	    }
+	} else if (tag->type == NTAG_21x) {
+	    p = ntag21x_error_lookup(NTAG_21x(tag)->last_error);
 	}
     }
     return p;

libfreefare/freefare.h

@@ -93,6 +93,7 @@ bool		 is_mifare_ultralightc_on_reader(nfc_device *device, nfc_iso14443a_info na
 
 
 bool		 ntag21x_taste(nfc_device *device, nfc_target target);
+uint8_t		 ntag21x_last_error(FreefareTag tag);
 
 /* NTAG21x access features */
 #define NTAG_PROT 0x80
@@ -102,6 +103,7 @@ bool		 ntag21x_taste(nfc_device *device, nfc_target target);
 #define NTAG_AUTHLIM 0x07
 
 enum ntag_tag_subtype {
+    NTAG_UNKNOWN,
     NTAG_213,
     NTAG_215,
     NTAG_216
@@ -367,6 +369,8 @@ bit 0: PICC master key frozen (reversible with configuration change or when form
 /* Error code managed by the library */
 
 #define CRYPTO_ERROR            0x01
+#define TAG_INFO_MISSING_ERROR	0xBA
+#define UNKNOWN_TAG_TYPE_ERROR	0xBB
 
 struct mifare_desfire_aid;
 typedef struct mifare_desfire_aid *MifareDESFireAID;

libfreefare/freefare_internal.h

@@ -243,6 +243,8 @@ struct ntag21x_tag {
     uint8_t minor_product_version;
     uint8_t storage_size;
     uint8_t protocol_type;
+
+    uint8_t last_error;
 };
 
 struct ntag21x_key {
@@ -250,6 +252,8 @@ struct ntag21x_key {
     uint8_t pack[2]; // 2B Password Acknowlege
 };
 
+const char      *ntag21x_error_lookup(uint8_t code);
+
 /*
  * FreefareTag assertion macros
  *

libfreefare/ntag21x.c

@@ -44,6 +44,8 @@
 	    {return errno = EINVAL, -1;} \
 	    else if(NTAG_21x(tag)->subtype == NTAG_216&&page>0xE6) \
 	    {return errno = EINVAL, -1;} \
+	    else if(NTAG_21x(tag)->subtype == NTAG_UNKNOWN) \
+	    {return errno = EINVAL, -1;} \
 	} else { \
 	    if(NTAG_21x(tag)->subtype == NTAG_213&&page>0x2C) \
 	    {return errno = EINVAL, -1;} \
@@ -51,6 +53,8 @@
 	    {return errno = EINVAL, -1;} \
 	    else if(NTAG_21x(tag)->subtype == NTAG_216&&page>0xE6) \
 	    {return errno = EINVAL, -1;} \
+	    else if(NTAG_21x(tag)->subtype == NTAG_UNKNOWN) \
+	    {return errno = EINVAL, -1;} \
 	} \
     } while (0)
 
@@ -113,14 +117,15 @@ _ntag21x_tag_new(nfc_device *device, nfc_target target)
 	tag->device = device;
 	tag->info = target;
 	tag->active = 0;
-	NTAG_21x(tag)->subtype = NTAG_213; // Set tag subtype
+	NTAG_21x(tag)->subtype = NTAG_UNKNOWN;
-	NTAG_21x(tag)->vendor_id = 0x04;
+	NTAG_21x(tag)->vendor_id = 0x00;
-	NTAG_21x(tag)->product_type = 0x04;
+	NTAG_21x(tag)->product_type = 0x00;
-	NTAG_21x(tag)->product_subtype = 0x02;
+	NTAG_21x(tag)->product_subtype = 0x00;
-	NTAG_21x(tag)->major_product_version = 0x01;
+	NTAG_21x(tag)->major_product_version = 0x00;
 	NTAG_21x(tag)->minor_product_version = 0x00;
-	NTAG_21x(tag)->storage_size = 0x0f;
+	NTAG_21x(tag)->storage_size = 0x00;
-	NTAG_21x(tag)->protocol_type = 0x03;
+	NTAG_21x(tag)->protocol_type = 0x00;
+	NTAG_21x(tag)->last_error = OPERATION_OK;
     }
 
     return tag;
@@ -137,14 +142,15 @@ _ntag21x_tag_reuse(FreefareTag old_tag)
 	tag->device = old_tag->device;
 	tag->info = old_tag->info;
 	tag->active = 0;
-	NTAG_21x(tag)->subtype = NTAG_213; // Set tag subtype
+	NTAG_21x(tag)->subtype = NTAG_21x(old_tag)->subtype;
-	NTAG_21x(tag)->vendor_id = 0x04;
+	NTAG_21x(tag)->vendor_id = NTAG_21x(old_tag)->vendor_id;
-	NTAG_21x(tag)->product_type = 0x04;
+	NTAG_21x(tag)->product_type = NTAG_21x(old_tag)->product_type;
-	NTAG_21x(tag)->product_subtype = 0x02;
+	NTAG_21x(tag)->product_subtype = NTAG_21x(old_tag)->product_subtype;
-	NTAG_21x(tag)->major_product_version = 0x01;
+	NTAG_21x(tag)->major_product_version = NTAG_21x(old_tag)->major_product_version;
-	NTAG_21x(tag)->minor_product_version = 0x00;
+	NTAG_21x(tag)->minor_product_version = NTAG_21x(old_tag)->minor_product_version;
-	NTAG_21x(tag)->storage_size = 0x0f;
+	NTAG_21x(tag)->storage_size = NTAG_21x(old_tag)->storage_size;
-	NTAG_21x(tag)->protocol_type = 0x03;
+	NTAG_21x(tag)->protocol_type = NTAG_21x(old_tag)->protocol_type;
+	NTAG_21x(tag)->last_error = NTAG_21x(old_tag)->last_error;
     }
 
     return tag;
@@ -282,7 +288,8 @@ ntag21x_get_info(FreefareTag tag)
 	NTAG_21x(tag)->subtype = NTAG_216;
 	break;
     default:
-	NTAG_21x(tag)->subtype = NTAG_213;
+	NTAG_21x(tag)->last_error = UNKNOWN_TAG_TYPE_ERROR;
+	return -1;
     }
     return 0;
 }
@@ -309,6 +316,7 @@ ntag21x_get_last_page(FreefareTag tag)
     case NTAG_216:
 	return 0xE6;
     default:
+	NTAG_21x(tag)->last_error = TAG_INFO_MISSING_ERROR;
 	return 0x00;
     }
 }
@@ -348,6 +356,10 @@ ntag21x_read_signature(FreefareTag tag, uint8_t *data)
 int
 ntag21x_set_pwd(FreefareTag tag, uint8_t data[4]) // Set password
 {
+    if (NTAG_21x(tag)->subtype == NTAG_UNKNOWN) {
+	NTAG_21x(tag)->last_error = TAG_INFO_MISSING_ERROR;
+	return -1;
+    }
     uint8_t page = ntag21x_get_last_page(tag) - 1; // PWD page is located 1 before last page
     int res = ntag21x_write(tag, page, data);
     return res;
@@ -356,6 +368,10 @@ ntag21x_set_pwd(FreefareTag tag, uint8_t data[4]) // Set password
 int
 ntag21x_set_pack(FreefareTag tag, uint8_t data[2]) // Set pack
 {
+    if (NTAG_21x(tag)->subtype == NTAG_UNKNOWN) {
+	NTAG_21x(tag)->last_error = TAG_INFO_MISSING_ERROR;
+	return -1;
+    }
     BUFFER_INIT(buff, 4);
     BUFFER_APPEND_BYTES(buff, data, 2);
     BUFFER_APPEND(buff, 0x00);
@@ -382,6 +398,10 @@ ntag21x_set_key(FreefareTag tag, const NTAG21xKey key) // Set key
 int
 ntag21x_set_auth(FreefareTag tag, uint8_t byte) // Set AUTH0 byte (from which page starts password protection)
 {
+    if (NTAG_21x(tag)->subtype == NTAG_UNKNOWN) {
+	NTAG_21x(tag)->last_error = TAG_INFO_MISSING_ERROR;
+	return -1;
+    }
     BUFFER_INIT(cdata, 4);
     int page = ntag21x_get_last_page(tag) - 3; // AUTH0 byte is on 4th page from back
     int res;
@@ -396,6 +416,10 @@ ntag21x_set_auth(FreefareTag tag, uint8_t byte) // Set AUTH0 byte (from which pa
 int
 ntag21x_get_auth(FreefareTag tag, uint8_t *byte) // Get AUTH0 byte
 {
+    if (NTAG_21x(tag)->subtype == NTAG_UNKNOWN) {
+	NTAG_21x(tag)->last_error = TAG_INFO_MISSING_ERROR;
+	return -1;
+    }
     BUFFER_INIT(cdata, 4);
     int page = ntag21x_get_last_page(tag) - 3; // AUTH0 byte is on 4th page from back
     int res;
@@ -409,6 +433,10 @@ ntag21x_get_auth(FreefareTag tag, uint8_t *byte) // Get AUTH0 byte
 int
 ntag21x_access_enable(FreefareTag tag, uint8_t byte) // Enable access feature in ACCESS byte
 {
+    if (NTAG_21x(tag)->subtype == NTAG_UNKNOWN) {
+	NTAG_21x(tag)->last_error = TAG_INFO_MISSING_ERROR;
+	return -1;
+    }
     BUFFER_INIT(cdata, 4);
     int page = ntag21x_get_last_page(tag) - 2; // ACCESS byte is on 3th page from back
     int res;
@@ -423,6 +451,10 @@ ntag21x_access_enable(FreefareTag tag, uint8_t byte) // Enable access feature in
 int
 ntag21x_access_disable(FreefareTag tag, uint8_t byte) // Disable access feature in ACCESS byte
 {
+    if (NTAG_21x(tag)->subtype == NTAG_UNKNOWN) {
+	NTAG_21x(tag)->last_error = TAG_INFO_MISSING_ERROR;
+	return -1;
+    }
     BUFFER_INIT(cdata, 4);
     int page = ntag21x_get_last_page(tag) - 2; // ACCESS byte is on 3th page from back
     int res;
@@ -437,6 +469,10 @@ ntag21x_access_disable(FreefareTag tag, uint8_t byte) // Disable access feature
 int
 ntag21x_get_access(FreefareTag tag, uint8_t *byte) // Get ACCESS byte
 {
+    if (NTAG_21x(tag)->subtype == NTAG_UNKNOWN) {
+	NTAG_21x(tag)->last_error = TAG_INFO_MISSING_ERROR;
+	return -1;
+    }
     BUFFER_INIT(cdata, 4);
     uint8_t page = ntag21x_get_last_page(tag) - 2; // ACCESS byte is on 3th page from back
     int res;
@@ -464,6 +500,10 @@ ntag21x_check_access(FreefareTag tag, uint8_t byte, bool *result) // Check if ac
 int
 ntag21x_get_authentication_limit(FreefareTag tag, uint8_t *byte) // Get authentication limit
 {
+    if (NTAG_21x(tag)->subtype == NTAG_UNKNOWN) {
+	NTAG_21x(tag)->last_error = TAG_INFO_MISSING_ERROR;
+	return -1;
+    }
     BUFFER_INIT(cdata, 4);
     uint8_t page = ntag21x_get_last_page(tag) - 2; // ACCESS byte is on 3th page from back
     int res;
@@ -480,6 +520,10 @@ ntag21x_set_authentication_limit(FreefareTag tag, uint8_t byte) // Set authentic
 {
     if (byte > 7) // Check for invalid range of auth limit
 	return -1;
+    if (NTAG_21x(tag)->subtype == NTAG_UNKNOWN) {
+	NTAG_21x(tag)->last_error = TAG_INFO_MISSING_ERROR;
+	return -1;
+    }
 
     BUFFER_INIT(cdata, 4);
     int page = ntag21x_get_last_page(tag) - 2; // ACCESS byte is on 3th page from back

libfreefare/ntag21x_error.c

@@ -0,0 +1,41 @@
+#include <sys/types.h>
+
+#include <stdlib.h>
+
+#include <freefare.h>
+
+#include "freefare_internal.h"
+
+#define EM(e) { e, #e }
+
+static struct ntag21x_error_message {
+    uint8_t code;
+    const char *message;
+} ntag21x_error_messages[] = {
+    EM(OPERATION_OK),
+    EM(TAG_INFO_MISSING_ERROR),
+    EM(UNKNOWN_TAG_TYPE_ERROR),
+    { 0, NULL }
+};
+
+const char *
+ntag21x_error_lookup(uint8_t code)
+{
+    struct ntag21x_error_message *e = ntag21x_error_messages;
+    while (e->message) {
+	if (e->code == code)
+	    return (e->message);
+	e++;
+    }
+
+    return "Invalid error code";
+}
+
+uint8_t
+ntag21x_last_error(FreefareTag tag)
+{
+    if (tag->type != NTAG_21x)
+	return 0;
+
+    return NTAG_21x(tag)->last_error;
+}