<?php
/**
 * mock.snmp.inc.php
 *
 * Mock functions from includes/snmp.inc.php to allow tests to run without real snmp
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 * @package    LibreNMS
 * @link       http://librenms.org
 * @copyright  2016 Tony Murray
 * @author     Tony Murray <murraytony@gmail.com>
 */

$snmpMockCache = array();

/**
 * Cache the data from an snmprec file
 * in ./tests/snmpsim/
 *
 * @param string $file the snmprec file name (excluding .snmprec)
 */
function cache_snmprec($file)
{
    global $config, $snmpMockCache;
    if (isset($snmpMockCache[$file])) {
        return;
    }
    $snmpMockCache[$file] = array();

    $data = file_get_contents($config['install_dir'] . "/tests/snmpsim/$file.snmprec");
    $line = strtok($data, "\r\n");
    while ($line !== false) {
        list($oid, $type, $data) = explode('|', $line, 3);
        if ($type == 4) {
            $data = trim($data);
        } elseif ($type == 6) {
            $data = trim($data, '.');
        }

        $snmpMockCache[$file][$oid] = array($type, $data);
        $line = strtok("\r\n");
    }
}

/**
 * Get all data of the specified $community from the snmprec cache
 *
 * @param string $community snmp community to return
 * @return array array of the data containing: [$oid][$type, $data]
 * @throws Exception this $community is not cached
 */
function snmprec_get($community)
{
    global $snmpMockCache;
    cache_snmprec($community);
    d_echo($snmpMockCache);

    if (isset($snmpMockCache[$community])) {
        return $snmpMockCache[$community];
    }

    throw new Exception("SNMPREC: community $community not cached");
}

/**
 * Get an $oid from the specified $community
 *
 * @param string $community the community to fetch data from
 * @param string $oid numeric oid of data to fetch
 * @return array array of the data containing: [$type, $data]
 * @throws Exception this $oid is not cached
 */
function snmprec_get_oid($community, $oid)
{
    global $snmpMockCache;
    cache_snmprec($community);

    if (isset($snmpMockCache[$community]) && isset($snmpMockCache[$community][$oid])) {
        return $snmpMockCache[$community][$oid];
    }

    throw new Exception("SNMPREC: oid $community:$oid not cached");
}

/**
 * Get the numeric oid of an oid
 * The leading dot is ommited by default to be compatible with snmpsim
 *
 * @param string $oid the oid to tranlslate
 * @param string $mib mib to use
 * @param string $mibdir mib dir to look for mib in
 * @return string the oid in numeric format (.1.3.4.5)
 * @throws Exception Could not translate the oid
 */
function snmp_translate_number($oid, $mib = null, $mibdir = null)
{
    global $config;

    // optimizations (35s -> 1.6s on my laptop)
    if ($oid == 'SNMPv2-MIB::sysDescr.0') {
        return '1.3.6.1.2.1.1.1.0';
    }
    if ($oid == 'SNMPv2-MIB::sysObjectID.0') {
        return '1.3.6.1.2.1.1.2.0';
    }
    if ($oid == 'ENTITY-MIB::entPhysicalDescr.1') {
        return '1.3.6.1.2.1.47.1.1.1.1.2.1';
    }
    if ($oid == 'SML-MIB::product-Name.0') {
        return '1.3.6.1.4.1.2.6.182.3.3.1.0';
    }
    if ($oid == 'ENTITY-MIB::entPhysicalMfgName.1') {
        return '1.3.6.1.2.1.47.1.1.1.1.12.1';
    }
    if ($oid == 'GAMATRONIC-MIB::psUnitManufacture.0') {
        return '1.3.6.1.4.1.6050.1.1.2.0';
    }
    // end optimizations

    if (preg_match('/^[\.\d]*$/', $oid)) {
        return ltrim($oid, '.');
    }

    $cmd = "snmptranslate -IR -On $oid";
    $cmd .= ' -M ' . (isset($mibdir) ? $mibdir : $config['mibdir']);
    if (isset($mib) && $mib) {
        $cmd .= " -m $mib";
    }

    $number = shell_exec($cmd);

    if (empty($number)) {
        throw new Exception('Could not translate oid: ' . $oid . PHP_EOL . 'Tried: ' . $cmd);
    }

    return trim($number, ". \n\r");
}

function snmp_translate_type($oid, $mib = null, $mibdir = null)
{
    global $config;

    $cmd = "snmptranslate -IR -Td $oid";
    $cmd .= ' -M ' . (isset($mibdir) ? $mibdir : $config['mibdir']);
    if (isset($mib) && $mib) {
        $cmd .= " -m $mib";
    }

    $result = shell_exec($cmd);

    if (empty($result)) {
        throw new Exception('Could not translate oid: ' . $oid . PHP_EOL . 'Tried: ' . $cmd);
    }

    if (str_contains($result, 'OCTET STRING')) {
        return 4;
    }
    if (str_contains($result, 'Integer32')) {
        return 2;
    }
    if (str_contains($result, 'NULL')) {
        return 5;
    }
    if (str_contains($result, 'OBJECT IDENTIFIER')) {
        return 6;
    }
    if (str_contains($result, 'IpAddress')) {
        return 64;
    }
    if (str_contains($result, 'Counter32')) {
        return 65;
    }
    if (str_contains($result, 'Gauge32')) {
        return 66;
    }
    if (str_contains($result, 'TimeTicks')) {
        return 67;
    }
    if (str_contains($result, 'Opaque')) {
        return 68;
    }
    if (str_contains($result, 'Counter64')) {
        return 70;
    }

    throw new Exception('Unknown type');
}

// Mocked functions

function snmp_get($device, $oid, $options = null, $mib = null, $mibdir = null)
{
    $community = $device['community'];
    $num_oid = snmp_translate_number($oid, $mib, $mibdir);

    try {
        $data = snmprec_get_oid($community, $num_oid);

        $result = $data[1];
        if ($data[0] == 6) {
            $result = '.' . $data[1];
        }

        d_echo("[SNMP] snmpget $community $num_oid: $result\n");

        return $result;
    } catch (Exception $e) {
        d_echo("[SNMP] snmpget $community $num_oid: no data\n");
        return false;
    }
}

function snmp_walk($device, $oid, $options = null, $mib = null, $mibdir = null)
{
    $community = $device['community'];
    $dev = snmprec_get($community);
    $num_oid = snmp_translate_number($oid, $mib, $mibdir);

    $output = '';
    foreach ($dev as $key => $data) {
        if (starts_with($key, $num_oid)) {
            if ($data[0] == 6) {
                $output .= '.' . $data[1] . PHP_EOL;
            } else {
                $output .= $data[1] . PHP_EOL;
            }
        }
    }

    d_echo("[SNMP] snmpwalk $community $num_oid: ");
    if (empty($output)) {
        d_echo("no data\n");
        // does this match the behavior of the real snmp_walk()?
        return false;
    } else {
        d_echo($output);
        return $output;
    }
}

function register_mibs()
{
    // stub
}

function getHostOS($device)
{
    global $config;

    $sysDescr = snmp_get($device, "SNMPv2-MIB::sysDescr.0", "-Ovq");
    $sysObjectId = snmp_get($device, "SNMPv2-MIB::sysObjectID.0", "-Ovqn");

    d_echo("| $sysDescr | $sysObjectId | \n");

    $os = null;
    $pattern = $config['install_dir'] . '/includes/discovery/os/*.inc.php';
    foreach (glob($pattern) as $file) {
        include $file;
        if (isset($os)) {
            return $os;
        }
    }

    return "generic";
}