@ledgerhq/hw-transport-node-hid-noevents/src/TransportNodeHid.ts

Ledger Hardware Wallet Node implementation of the communication layer, using node-hid. without usb events

import HID, { Device } from "node-hid";
import { LogType, TraceContext } from "@ledgerhq/logs";
import Transport, {
  Observer,
  DescriptorEvent,
  Subscription,
  Device as TransportDevice,
} from "@ledgerhq/hw-transport";
import {
  DeviceModel,
  identifyProductName,
  identifyUSBProductId,
  ledgerUSBVendorId,
} from "@ledgerhq/devices";
import hidFraming from "./hid-framing";
import {
  TransportError,
  DisconnectedDevice,
  DisconnectedDeviceDuringOperation,
} from "@ledgerhq/errors";

const filterInterface = device =>
  ["win32", "darwin"].includes(process.platform)
    ? device.usagePage === 0xffa0
    : device.interface === 0;

export function getDevices(): (Device & { deviceName?: string })[] {
  return HID.devices(ledgerUSBVendorId, 0x0).filter(filterInterface);
}

/**
 * node-hid Transport minimal implementation
 * @example
 * import TransportNodeHid from "@ledgerhq/hw-transport-node-hid-noevents";
 * ...
 * TransportNodeHid.create().then(transport => ...)
 */
export default class TransportNodeHidNoEvents extends Transport {
  /**
   *
   */
  static isSupported = (): Promise<boolean> => Promise.resolve(typeof HID.HID === "function");

  /**
   *
   */
  static list = (): Promise<any> => Promise.resolve(getDevices().map(d => d.path));

  /**
   */
  static listen = (observer: Observer<DescriptorEvent<any>>): Subscription => {
    getDevices().forEach(device => {
      const deviceModel = identifyUSBProductId(device.productId);
      observer.next({
        type: "add",
        descriptor: device.path,
        deviceModel,
        device: device as unknown as TransportDevice,
      });
    });
    observer.complete();
    return {
      unsubscribe: () => {},
    };
  };

  /**
   * if path="" is not provided, the library will take the first device
   */
  static open(path: string | null | undefined) {
    return Promise.resolve().then(() => {
      if (path) {
        return new TransportNodeHidNoEvents(new HID.HID(path));
      }

      const device = getDevices()[0];
      if (!device) throw new TransportError("NoDevice", "NoDevice");
      return new TransportNodeHidNoEvents(new HID.HID(device.path as string));
    });
  }

  device: HID.HID;
  deviceModel: DeviceModel | null | undefined;
  channel = Math.floor(Math.random() * 0xffff);
  packetSize = 64;
  disconnected = false;

  constructor(
    device: HID.HID,
    { context, logType }: { context?: TraceContext; logType?: LogType } = {},
  ) {
    super({ context, logType });
    this.updateTraceContext({ hidChannel: this.channel });
    this.device = device;

    // @ts-expect-error accessing low level API in C
    const info = device.getDeviceInfo();

    this.tracer.trace(`Connected to HID device ${!!info}`, { info });

    this.deviceModel = info && info.product ? identifyProductName(info.product) : null;
  }

  setDisconnected = () => {
    this.tracer.trace("Setting to disconnected", { alreadyDisconnected: this.disconnected });

    if (!this.disconnected) {
      this.emit("disconnect");
      this.disconnected = true;
    }
  };

  writeHID = (content: Uint8Array): Promise<void> => {
    const data = [0x00];

    for (let i = 0; i < content.length; i++) {
      data.push(content[i]);
    }

    try {
      this.device.write(data);
      return Promise.resolve();
    } catch (error: unknown) {
      this.tracer.trace(`Received an error during HID write: ${error}`, { error });

      let maybeMappedError = error;
      if (error instanceof Error) {
        maybeMappedError = new DisconnectedDeviceDuringOperation(error.message);
      }

      if (maybeMappedError instanceof DisconnectedDeviceDuringOperation) {
        this.tracer.trace("Disconnected during HID write");
        this.setDisconnected();
      }

      return Promise.reject(maybeMappedError);
    }
  };

  readHID = (): Promise<Buffer> =>
    new Promise((resolve, reject) =>
      this.device.read((e, res) => {
        if (!res) {
          return reject(new DisconnectedDevice());
        }

        if (e) {
          this.tracer.trace(`Received an error during HID read: ${e}`, { e });

          const maybeMappedError =
            e && e.message ? new DisconnectedDeviceDuringOperation(e.message) : e;

          if (maybeMappedError instanceof DisconnectedDeviceDuringOperation) {
            this.tracer.trace("Disconnected during HID read");
            this.setDisconnected();
          }

          reject(maybeMappedError);
        } else {
          const buffer = Buffer.from(res);
          resolve(buffer);
        }
      }),
    );

  /**
   * Exchange with the device using APDU protocol.
   *
   * @param apdu
   * @returns a promise of apdu response
   */
  async exchange(apdu: Buffer): Promise<Buffer> {
    const tracer = this.tracer.withUpdatedContext({
      function: "exchange",
    });
    tracer.trace("Exchanging APDU ...");

    const b = await this.exchangeAtomicImpl(async () => {
      const { channel, packetSize } = this;
      tracer.withType("apdu").trace(`=> ${apdu.toString("hex")}`, { channel, packetSize });

      const framingHelper = hidFraming(channel, packetSize);

      // Creates HID-framed chunks from the APDU to be sent to the device...
      const blocks = framingHelper.makeBlocks(apdu);

      for (let i = 0; i < blocks.length; i++) {
        await this.writeHID(blocks[i]);
      }

      // Read...
      let result;
      let acc;

      while (!(result = framingHelper.getReducedResult(acc))) {
        const buffer = await this.readHID();
        acc = framingHelper.reduceResponse(acc, buffer);
      }

      tracer.withType("apdu").trace(`<= ${result.toString("hex")}`, { channel, packetSize });
      return result;
    });

    return b as Buffer;
  }

  setScrambleKey() {}

  /**
   * release the USB device.
   */
  async close(): Promise<void> {
    await this.exchangeBusyPromise;
    this.device.close();
  }
}