OPNsense: Start/stop WireGuard based on CARP state change (place in /usr/local/etc/rc.syshook.d/carp/)

10-wireguard

#!/usr/local/bin/php
<?php

/*
 * Copyright (C) 2004 Scott Ullrich <sullrich@gmail.com>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
 * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 * AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
 * OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

require_once("config.inc");
require_once("interfaces.inc");
require_once("util.inc");

$subsystem = !empty($argv[1]) ? $argv[1] : '';
$type = !empty($argv[2]) ? $argv[2] : '';

if ($type != 'MASTER' && $type != 'BACKUP') {
    log_error("Carp '$type' event unknown from source '{$subsystem}'");
    exit(1);
}

if (!strstr($subsystem, '@')) {
    log_error("Carp '$type' event triggered from wrong source '{$subsystem}'");
    exit(1);
}

if ($type === "MASTER") {
    log_error("Enabling WireGuard due to CARP event '$type'");
    # Checking `isset` avoids a race condition during startup when the
    # WireGuard config stanza seems like it's not yet loaded. Without it, this
    # can create an extra, empty, invalid stanza that breaks WireGuard.
    if (isset($config['OPNsense']['wireguard']['general']['enabled'])) {
      $config['OPNsense']['wireguard']['general']['enabled'] = '1';
    }
    configd_run('wireguard start');
    write_config("Enable WireGuard due to CARP event '$type'", false);
} else {
    log_error("Disabling WireGuard due to CARP event '$type'");
    configd_run('wireguard stop');
    if (isset($config['OPNsense']['wireguard']['general']['enabled'])) {
        $config['OPNsense']['wireguard']['general']['enabled'] = '0';
    }
    write_config("Disable WireGuard due to CARP event '$type'", false);
}

It seems the script broke with opnsense/plugins@86c9e5c

The configd run now requires to give the wireguard instance as parameter.

So if you upgrade to 23.7.3 it breaks.

The following works:

$servers = (new \OPNsense\Wireguard\Server())->servers->server->iterateItems();

foreach ($servers as $key => $node) {
    if (!empty((string)$node->enabled)) {
        $backend->configdRun("wireguard start {$key}");
    }
}

// repeat for stop

This is now unnecessary as proper CARP support is now built into OPNsense with WireGuard since OPNsense 23.7.8 released 09 Nov 2023 and further improved in the latest OPNsense firmware.

The WireGuard follow CARP implementation by the OPNsense dev team is excellent and it works really well!