Card emulation

[Zhairgling]

Can we transfer data between 2 pn532 ? like android beam ? I have a raspberry pi 3 and Pn532 from adafruit in uart mode.

[Zhairgling]

I saw here (https://github.com/techniq/node-pn532/blob/emulate-tag/src/pn532.js) that there was a function intended to make emulation of code but when I test I am a little lost.

I want to clarify that I already manage to read and write on tags.

[techniq]

Hi @Zhairgling. The PN532 has the ability to be a writer as well as a reader, and I spent some time on the emulate-tag branch trying to get writing to work, but ultimately never had time to finish it. I also wasn't sure if being a simple writer was the same as Android Beam (if the later is more bi-directional communication). I do see Seeed Studios C library supports card emulation and snep (which I believe relates to Android Beam). I don't see me getting time to look at this for a while, but I accept PRs :). Between the User Guide and Datasheet (linked at the bottom of the README) and looking at Seeed Studio's implementation, it might not be too difficult to finish up.

[Zhairgling]

First of all thank you @techniq for the answer. I do not want to communicate with an android device. I refer to this system of operation only as an example. I am only trying to exchange a json object between two pn532. Can you tell me what was not working when you were working.

[techniq]

I also see Adafruit's PN532 C++ library has a PR to add tag emulation. You might take a look at the changes and see what needs to be done. Most of it comes down to getting the command structure correct.

[techniq]

To be honest, I don't remember exactly (it's been a little while). I remember I was trying to use my Android phone with NFC Tools to scan my pn532 breakout board but I think I was having trouble understanding how to attach the payload of the data to send.

[Zhairgling]

Thank you for the advices you gave me.
I'm a little lost though. I think I'll come back to you if I have any questions. But I confess that I am afraid of not being able to make it work.

[techniq]

Looking at the SimpleTag.ino file within the test scripts on the Adafruit PR, it looks like you need to first initialize (nfc.TgInitAsTarget()) and then setup a response buffer/handler (nfc.TgGetData(...)) and then ultimately send the data (nfc.TgSetData(...))

#include <Adafruit_PN532.h>

#define SCK     (2)
#define MOSI    (3)
#define SS      (4)
#define MISO    (5)

boolean TgInit = false;

Adafruit_PN532 nfc(SCK, MISO, MOSI, SS);

void setup() {
  Serial.begin(115200);
  nfc.begin();

  uint8_t versiondata = nfc.getFirmwareVersion();
  if (! versiondata) {
    Serial.println("Didn't find PN532 on RX board!");
    while (1); //halt
  }

  nfc.SAMConfig();
  Serial.println("Boards initialized and ready...");
}

void loop() {
  uint8_t sendbuf[] = {0x04, 0x03, 0x02, 0x01};
  uint8_t resbuf[16];
  uint8_t reslen;
  if(nfc.TgInitAsTarget()) {
    Serial.println("Tag Emulation Successful");
    if(!nfc.TgGetData(resbuf, &reslen)) {
      Serial.println("GetData Fail");
    }
    nfc.TgSetData(sendbuf, sizeof(sendbuf));
    Serial.print("Response: ");
    nfc.PrintHex(resbuf, reslen);
    Serial.println("Sent data: ");
    nfc.PrintHex(sendbuf, sizeof(sendbuf));
//    while(1);
  }
  delay(1000);
}

I think I was on the right track with emulateTag (i.e. TgInitAsTarget), emulateGetData (i.e. TgGetData) and emulateSetData (i.e. TgSetData) but maybe not knowing I needed to call all 3 each time to setup the transfer...

Looking at what I had done, I think I was using Seeed Studio's emulatetag.cpp as reference, trying to figure it out. If you want to give it a shot, I would work from their impl. and see where `node-pn532' is lacking.

[techniq]

Page 21 of the User Manual titled ISO/IEC14443-4 PICC emulation concept and pages 151-165 on TgInitAsTarget, TgGetData, and TgSetData might come in handy, but ultimately working by example (Seeed/Adafruit impl.) will probably give you the best idea on how to implement.

I wish I had more time to look at this, but as of right now, just giving comments/feedback is the best I can do (for a while at least).

[Zhairgling]

Hello, I bent over it tonight. I prepared two PI and two pn532. They work well both. I even was able to test the emulation function of tag in the shell with the examples of the libnfc.
I have needed a tip to choose the best way to implement it in the pn532 module. Should I load the old branch of your work or implement it myself in the latest version of the module?

[techniq]

I would definitely use the master branch and not the old branch. Will make merging easier.

…

On Wed, Jan 25, 2017, 5:35 AM Zhairgling ***@***.***> wrote: Hello, I bent over it tonight. I prepared two PI and two pn532. They work well both. I even was able to test the emulation function of tag in the shell with the examples of the libnfc. I have needed a tip to choose the best way to implement it in the pn532 module. Should I load the old branch of your work or implement it myself in the latest version of the module? — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub <#12 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AAK1RIPxRZdO1CJa84nGKkqECvfEzQ6eks5rVyWIgaJpZM4LsF1P> .

[Zhairgling]

I am currently working on it but I do not see very well the interest of the emulateSetData () function. Since there is one of the two configured as target the other just has to write on it, then reverse !?

[Zhairgling]

Can you explain me the switch in the emulateGetData() function ?

emulateGetData() {
        logger.info('Emulate get data...');
        return this.sendCommand([c.COMMAND_TG_GET_DATA])
        .then((frame) => {
            var body = frame.getDataBody();
            logger.debug('Frame data from emulate get data read:', util.inspect(body));
            var status = body[0];
            if (status === 0x13) {
                logger.warn('The data format does not match to the specification.');
            }
            // var dataIn = body.slice(1, body.length - 1); // skip status byte and last byte (not part of memory)
            // 00 00 a4 04 00 07 d2 76 00 00 85 01 01 00 26
            var cla = body[1]
            var instruction = body[2];
            var parameter1 = body[3];
            var parameter2 = body[4];
            var commandLength = body[5];
            var data = body.slice(6, commandLength);
            logger.debug('instruction', instruction);
            logger.debug('parameter1', parameter1);
            logger.debug('parameter2', parameter2);
            logger.debug('commandLength', commandLength);
            logger.debug('data', util.inspect(data));
            switch(instruction) {          ////////              <==========================
                case c.ISO7816_SELECT_FILE:
                    logger.info('Select file');
                    if (parameter1 === 0x00) {
                        logger.info('Select by Id');
                    }
                    if (parameter1 === 0x04) {
                        logger.info('Select by name');
                    }
                 /*   case C_APDU_P1_SELECT_BY_ID:
                        if(p2 != 0x0c){
                            DMSG("C_APDU_P2 != 0x0c\n");
                           // setResponse(COMMAND_COMPLETE, rwbuf, &sendlen);
                        } else if(lc == 2 && rwbuf[C_APDU_DATA] == 0xE1 && (rwbuf[C_APDU_DATA+1] == 0x03 || rwbuf[C_APDU_DATA+1] == 0x04)){
                           // setResponse(COMMAND_COMPLETE, rwbuf, &sendlen);
                            if(rwbuf[C_APDU_DATA+1] == 0x03){
                                currentFile = CC;
                            } else if(rwbuf[C_APDU_DATA+1] == 0x04){
                                currentFile = NDEF;
                            }
                        } else {
                           // setResponse(TAG_NOT_FOUND, rwbuf, &sendlen);
                        }
                        break;
                        case C_APDU_P1_SELECT_BY_NAME:
                        const uint8_t ndef_tag_application_name_v2[] = {0, 0x7, 0xD2, 0x76, 0x00, 0x00, 0x85, 0x01, 0x01 };
                        if(0 == memcmp(ndef_tag_application_name_v2, rwbuf + C_APDU_P2, sizeof(ndef_tag_application_name_v2))){
                           // setResponse(COMMAND_COMPLETE, rwbuf, &sendlen);
                        } else{
                            DMSG("function not supported\n");
                          //  setResponse(FUNCTION_NOT_SUPPORTED, rwbuf, &sendlen);
                        }
                        break;
                    break;*/
                case c.ISO7816_READ_BINARY:
                    logger.info('Read binary');
                    break;
                case c.ISO7816_UPDATE_BINARY:
                    logger.info('Update binary');
                    break;
                default:
                    logger.warn('Command not supported');
            }
            return data;
        });
    }

[techniq]

I'll be honest, I'm not sure what it does :D.

I think at the time I copied Seeed Studio's C++ implementation and was slowly trying to break it down to understand it, but I didn't get that far... :(

I think it would be best if we scraped that and looked at Adafruit's PR C++ implementation for TgGetData since it looks to be simpler (and we can build it out after we have a better understanding...).

[Zhairgling]

I have worked on the emulateTag() function.

here is my work :

     emulateTag() {
        logger.info('Emulating tag...');
        var commAsTarget= 0x8C;
        var mode = 0x05; // PICC only, Passive Only
        var sens_res = [0x08, 0x00];
        var nfcId1t = [0x12, 0x34, 0x56];
        var sel_res = [0x60];
        var mifareParams = [].concat(sens_res, nfcId1t, sel_res);
        var felicaParams = [0,0,0,0,0,0,0,0,
                           0,0,0,0,0,0,0,0,
                           0,0];
        var nfcId3t = [0,0,0,0,0,0,0,0,0,0];
        var generalBytesLength = 0;
        var historicalBytesLength =  0;
        var commandBuffer = [
            commAsTarget,
            mode,
            mifareParams,
            felicaParams,
            nfcId3t,
            generalBytesLength,
            historicalBytesLength
        ];
        console.log('commandBuffer : '+ commandBuffer);
        return this.sendCommand(commandBuffer)
            .then((frame) => {

            var body = frame.getDataBody();
            logger.debug('body', util.inspect(body));
            var mode = body[0];
            console.log('mode', mode);
            logger.debug('mode', mode);
           
        });
    }
    

but i can't have any response by the pn532 after send the commandBuffer.