address verification attempt

index.js

'use strict'

// TODO: Replace absolute path
const smtp_client_module = require('/usr/lib/node_modules/Haraka/smtp_client.js');

exports.register = function () {
  this.inherits('haraka-plugin-redis');

  this.load_config();

  // Skip if explicitly disabled
  if (!this.cfg.main.enabled) {
    this.loginfo("Module is explicitly disabled!");
    return;
  }

  this.merge_redis_ini();

  this.register_hook('init_master', 'init_redis_plugin');
  this.register_hook('init_child', 'init_redis_plugin');

  this.register_hook('rcpt', 'rcpt_hook');
}

exports.load_config = function () {
  const plugin = this

  plugin.cfg = plugin.config.get('recipient-routes-probe.ini', {
        booleans: [
          '+enabled',
        ]
      },
      () => {
        plugin.load_config();
      }
  );

  // set default cache ttl
  plugin.cfg.cache.ttl = this.cfg.cache.ttl || 14400;
  plugin.cfg.cache.negative_ttl = this.cfg.cache.negative_ttl || 120;

  // TODO: Remove debug
  this.loginfo("cache.ttl: " + plugin.cfg.cache.ttl);
  this.loginfo("cache.negative_ttl: " + plugin.cfg.cache.negative_ttl);
}


exports.get_rcpt_address = function (rcpt) {
  if (!rcpt.host) return [ rcpt.address().toLowerCase() ];
  return [ rcpt.address().toLowerCase(), rcpt.host.toLowerCase() ];
}

exports.probe_recipient = function(connection, cfg, address) {
  const plugin = this;
  const txn = connection?.transaction;
  let success = false;

  // this.loginfo("Connection: " + JSON.stringify(connection));
  // this.loginfo("Plugin: " + JSON.stringify(plugin));
  // this.loginfo("Target server: " + JSON.stringify(cfg));

  // Probe target MX
  smtp_client_module.get_client_plugin(plugin, connection, cfg, (err, smtp_client) => {
    // smtp_client.next = next;

    function get_rs () {
      if (txn) return txn.results;
      return connection.results;
    }

    function dead_sender () {
      if (smtp_client.is_dead_sender(plugin, connection)) {
        get_rs().add(plugin, { err: 'dead sender' });
        return true;
      }
      return false;
    }

    smtp_client.on('rcpt', () => {
      // Recipient accepted
      success = true;
      smtp_client.release();
    });

    smtp_client.on('mail', () => {
      // Send RCPT
      smtp_client.send_command('RCPT', `TO: ${address}`);
    });

    smtp_client.on('rset', () => {
      // Send FROM
      smtp_client.send_command('MAIL', `FROM: <probe@mx1-ng.swisscenter.com>`);
    });

    smtp_client.on('bad_code', () => {
      // Something went wrong
      smtp_client.release();
    });

  });

  return success;
}

exports.shutdown = function () {
  if (this.db) this.db.quit();
}

exports.rcpt_hook = async function (next, connection, params) {
  const txn = connection.transaction;

  // Skip if no transaction available
  if (!txn) return next();

  // Skip if no domain is found in RCPT address
  const [address, domain] = this.get_rcpt_address(params[0]);
  if (!domain) {
    txn.results.add(this, {fail: 'rcpt!domain'});
    return next();
  }

  // All fine until now
  this.loginfo("Recipient address: " + address);
  this.loginfo("Recipient domain: " + domain);

  let target_mx = { host: 'mail01.swisscenter.com', 'port': 22 };

  // Check if recipient is accepted by target MX
  if (this.probe_recipient(connection, target_mx, address)) {
    this.loginfo("Recipient " + address + " ACCEPTED by target MX " + target_mx['host'] + ':' + target_mx['port']);
  } else {
    this.loginfo("Recipient " + address + " REJECTED by target MX " + target_mx['host'] + ':' + target_mx['port']);
  }

  // Fire next hook
  next();
}