Sending APDUs

brmdoor_nfc.cpp

@@ -9,9 +9,23 @@
 
 using namespace std;
 
+ResponseAPDU::ResponseAPDU(const string &data)
+{
+    size_t len = data.size();
+    _valid = len >= 2;
+    
+    if (!_valid) {
+	return; 
+    }
+    
+    _sw = (uint8_t(data[len-2]) << 8) | uint8_t(data[len-1]);
+    _data = data.substr(0, len-2);
+}
+
 NFCDevice::NFCDevice() throw(NFCError):
     pollNr(20),
     pollPeriod(2),
+    apduTimeout(500),
     _nfcContext(NULL),
     _nfcDevice(NULL),
     _opened(false),
@@ -105,6 +119,36 @@ std::string NFCDevice::scanUID() throw(NFCError)
     return uid;
 }
 
+void NFCDevice::selectPassiveTarget() throw(NFCError)
+{
+    nfc_target nt;
+    while (nfc_initiator_select_passive_target(_nfcDevice, _modulations[0], NULL, 0, &nt) <= 0);
+}
+
+ResponseAPDU NFCDevice::sendAPDU(const string &apdu) throw(NFCError)
+{
+    int res;
+    uint8_t rapdu[512];
+    
+    if ((res = nfc_initiator_transceive_bytes(_nfcDevice, (uint8_t*)apdu.data(), apdu.size(),  
+                                              rapdu, 512, apduTimeout)) < 0) {
+	if (res == NFC_EOVFLOW) {
+	    throw NFCError("Response APDU too long");
+	}
+	
+	throw NFCError("Failed to transceive APDU");
+    } else {
+	string rapduData((char *)rapdu, res);
+      	ResponseAPDU responseApdu(rapduData);
+	
+	if (!responseApdu.valid()) {
+	    throw NFCError("Invalid response APDU was received");
+	}
+	
+	return responseApdu;
+    }
+}
+
 const nfc_modulation NFCDevice::_modulations[5] = {
         { /*.nmt = */ NMT_ISO14443A, /* .nbr = */ NBR_106 }
         //{ /*.nmt = */ NMT_ISO14443B, /* .nbr = */ NBR_106 },

brmdoor_nfc.h

@@ -29,6 +29,45 @@ protected:
     std::string _msg;
 };
 
+/**
+ * Represents response APDU for ISO14443-4.
+ */
+class ResponseAPDU
+{
+public:
+    
+    /** Parse response APDU from raw data */
+    ResponseAPDU(const std::string& data);
+    
+    ~ResponseAPDU() {}
+    
+    /** Return whole status word */
+    uint16_t sw() const {return _sw;}
+    
+    /** Return first byte of status word */
+    uint8_t sw1() const {return _sw >> 8;}
+    
+    /** Return second byte of status word */
+    uint8_t sw2() const {return _sw & 0xFF;}
+    
+    /** Return whether this is properly formed response */
+    bool valid() const {return _valid;}
+    
+    /** Returns APDU data */
+    const std::string& data() const {return _data;}
+
+private:
+    
+    /** Data from response, without SW1 and SW2 */
+    std::string _data;
+    
+   /** SW1 and SW2 */ 
+    uint16_t _sw;
+    
+   /** Whether response APDU has had enough data to be valid */ 
+    bool _valid;
+};
+
 /**
  * Represents one PN532 reader device. Config is taken from default
  * libnfc-specified location. That usually means first device found is used.
@@ -67,6 +106,20 @@ public:
      * @throws NFCError if polling failed
      */
     std::string scanUID() throw(NFCError);
+    
+    /**
+     * Wait for one passive or emulated target and select it by reader.
+     */
+    void selectPassiveTarget() throw(NFCError);
+    
+    /**
+     * Send APDU to passive or emulated target. The target must be already
+     * selected by selectPassiveTarget() or scanUID().
+     *
+     * @param apdu command APDU to send
+     * @param returns response APDU received from target
+     */
+    ResponseAPDU sendAPDU(const std::string& apdu) throw(NFCError);
 
     /** Open device explicitly. May be useful after explicit close */
     void open() throw(NFCError);
@@ -94,6 +147,11 @@ public:
      * (0x01 – 0x0F: 150ms – 2.25s)
      */
     uint8_t pollPeriod;
+    
+    /**
+     * Timeout for waiting response to sent APDU. Value -1 means wait forever.
+     */
+    int apduTimeout;
 
 protected:
 

test_nfc.py

@@ -2,9 +2,33 @@
 from brmdoor_nfc import NFCDevice, NFCError
 from binascii import hexlify
 
+def formatAPDU(apdu):
+	return " ".join(["%02X" % ord(b) for b in apdu])
+	
+# Reading of file E104, where usually NDEF message is
+hex_apdus = [
+	"00 A4 04 00 07 D2760000850101",
+	"00 a4 00 0c 02 E104",
+	"00 b0 00 00 30",
+] 
+
+apdus = [hex_apdu.replace(" ","").decode("hex") for hex_apdu in hex_apdus]
+
 try:
 	nfc = NFCDevice()
-	print hexlify(nfc.scanUID())
+	uid = nfc.scanUID()
+	print "UID", hexlify(uid)
+
+	print "Now trying to send ISO14443-4 APDUs"
+	try:
+		#nfc.selectPassiveTarget()
+		for apdu in apdus:
+			print "Command APDU:", formatAPDU(apdu)
+			rapdu = nfc.sendAPDU(apdu)
+			print "Response APDU valid: %s, SW %04x, data %s" % (rapdu.valid(), rapdu.sw(), hexlify(rapdu.data()))
+	except NFCError, e:
+		print "Failed to transmit APDU:", e.what()
+
 	print "Device is opened:", nfc.opened()
 	print "Closing device"
 	nfc.close()