<?php

/**
 * vrp.inc.php
 *
 * LibreNMS bgp_peers for Huawei VRP
 *
 * 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  2020 PipoCanaja
 * @author     PipoCanaja
 */

use LibreNMS\Config;
use LibreNMS\Exceptions\InvalidIpException;
use LibreNMS\Util\IP;

if (Config::get('enable_bgp')) {
    $bgpPeersCache = snmpwalk_cache_oid($device, 'hwBgpPeers', [], 'HUAWEI-BGP-VPN-MIB');

    if (count($bgpPeersCache) == 0) {
        //Either we have no BGP peer, or this VRP device does not support Huawei's own BGP MIB
        //Let's compare with standard BGP4-MIB.
        $bgpPeersCache_ietf = snmpwalk_cache_oid($device, 'bgpPeerRemoteAs', [], 'BGP4-MIB');
    }

    // So if we have HUAWEI BGP entries or if we don't have anything from HUAWEI nor BGP4-MIB
    if (count($bgpPeersCache) > 0 || count($bgpPeersCache_ietf) == 0) {
        $vrfs = dbFetchRows('SELECT vrf_id, vrf_name from `vrfs` WHERE device_id = ?', [$device['device_id']]);
        foreach ($vrfs as $vrf) {
            $map_vrf['byId'][$vrf['vrf_id']]['vrf_name'] = $vrf['vrf_name'];
            $map_vrf['byName'][$vrf['vrf_name']]['vrf_id'] = $vrf['vrf_id'];
        }
        $bgpPeersCache = snmpwalk_cache_oid($device, 'hwBgpPeers', [], 'HUAWEI-BGP-VPN-MIB');
        foreach ($bgpPeersCache as $key => $value) {
            $oid = explode(".", $key);
            $vrfInstance = $value['hwBgpPeerVrfName'];
            if ($oid[0] == 0) {
                $vrfInstance = '';
                $value['hwBgpPeerVrfName'] = '';
            }
            $address = str_replace($oid[0].".".$oid[1].".".$oid[2].".".$oid[3].".", '', $key);
            if ($oid[3] == 'ipv6') {
                $address = IP::fromHexString($address)->compressed();
            } elseif ($oid[3] != 'ipv4') {
                // we have a malformed OID reply, let's skip it
                continue;
            }

            $bgpPeers[$vrfInstance][$address] = $value;
            $bgpPeers[$vrfInstance][$address]['vrf_id'] = $map_vrf['byName'][$vrfInstance]['vrf_id'];
            $bgpPeers[$vrfInstance][$address]['afi'] = $oid[1];
            $bgpPeers[$vrfInstance][$address]['safi'] = $oid[2];
            $bgpPeers[$vrfInstance][$address]['typePeer'] =  $oid[3];
        }

        foreach ($bgpPeers as $vrfName => $vrf) {
            $vrfId = $map_vrf['byName'][$vrfName]['vrf_id'];
            $checkVrf = ' AND vrf_id = ? ';
            if (empty($vrfId)) {
                $checkVrf = ' AND `vrf_id` IS NULL ';
            }

            foreach ($vrf as $address => $value) {
                $astext = get_astext($value['hwBgpPeerRemoteAs']);
                if (dbFetchCell('SELECT COUNT(*) from `bgpPeers` WHERE device_id = ? AND bgpPeerIdentifier = ? ' . $checkVrf, [$device['device_id'], $address, $vrfId]) < '1') {
                    $peers = [
                        'device_id' => $device['device_id'],
                        'vrf_id' => $vrfId,
                        'bgpPeerIdentifier' => $address,
                        'bgpPeerRemoteAs' => $value['hwBgpPeerRemoteAs'],
                        'bgpPeerState' => $value['hwBgpPeerState'],
                        'bgpPeerAdminStatus' => 'stop',
                        'bgpLocalAddr' => '0.0.0.0',
                        'bgpPeerRemoteAddr' => $value['hwBgpPeerRemoteAddr'],
                        'bgpPeerInUpdates' => 0,
                        'bgpPeerOutUpdates' => 0,
                        'bgpPeerInTotalMessages' => 0,
                        'bgpPeerOutTotalMessages' => 0,
                        'bgpPeerFsmEstablishedTime' => $value['hwBgpPeerFsmEstablishedTime'],
                        'bgpPeerInUpdateElapsedTime' => 0,
                        'astext' => $astext,
                    ];
                    if (empty($vrfId)) {
                        unset($peers['vrf_id']);
                    }
                    dbInsert($peers, 'bgpPeers');
                    $seenPeer[$address]=1;

                    if (Config::get('autodiscovery.bgp')) {
                        $name = gethostbyaddr($address);
                        discover_new_device($name, $device, 'BGP');
                    }
                    echo '+';
                    $vrp_bgp_peer_count ++;
                } else {
                    dbUpdate(['bgpPeerRemoteAs' => $value['hwBgpPeerRemoteAs'], 'astext' => $astext], 'bgpPeers', 'device_id = ? AND bgpPeerIdentifier = ? AND vrf_id = ?', [$device['device_id'], $address, $vrfId]);
                    $seenPeer[$address]=1;
                    echo '.';
                    $vrp_bgp_peer_count ++;
                }
                if (dbFetchCell('SELECT COUNT(*) from `bgpPeers_cbgp` WHERE device_id = ? AND bgpPeerIdentifier = ? AND afi=? AND safi=?', array($device['device_id'], $value['hwBgpPeerRemoteAddr'], $value['afi'], $value['safi'])) < 1) {
                    $device['context_name'] = $vrfName;
                    add_cbgp_peer($device, ['ip' => $value['hwBgpPeerRemoteAddr']], $value['afi'], $value['safi']);
                    unset($device['context_name']);
                } else {
                    //nothing to update
                }
            }
        }
        // clean up peers
        $peers = dbFetchRows('SELECT `vrf_id`, `bgpPeerIdentifier` FROM `bgpPeers` WHERE `device_id` = ?', [$device['device_id']]);
        foreach ($peers as $value) {
            $vrfId = $value['vrf_id'];
            $checkVrf = ' AND vrf_id = ? ';
            if (empty($vrfId)) {
                $checkVrf = ' AND `vrf_id` IS NULL ';
            }
            $vrfName = $map_vrf['byId'][$vrfId]['vrf_name'];
            $address = $value['bgpPeerIdentifier'];
            if (isset($seenPeer[$address])) {
                continue; //we just added this peer
            }
            if ((empty($vrfId) && empty($bgpPeers[''][$address])) ||
                (!empty($vrfId) && !empty($vrfName) && empty($bgpPeers[$vrfName][$address])) ||
                (!empty($vrfId) && empty($vrfName))) {
                $deleted = dbDelete('bgpPeers', 'device_id = ? AND bgpPeerIdentifier = ? ' . $checkVrf, [$device['device_id'], $address, $vrfId]);

                echo str_repeat('-', $deleted);
                echo PHP_EOL;
            }
        }

        $af_query = "SELECT bgpPeerIdentifier, afi, safi FROM bgpPeers_cbgp WHERE `device_id`=? AND bgpPeerIdentifier=?";
        foreach (dbFetchRows($af_query, [$device['device_id'], $peer['ip']]) as $entry) {
            $afi  = $entry['afi'];
            $safi = $entry['safi'];
            $vrfName = $entry['context_name'];
            if (!exist($bgpPeersCache[$vrfName]) ||
                    !exist($bgpPeersCache[$vrfName][$entry['bgpPeerIdentifier']]) ||
                    $bgpPeersCache[$vrfName][$entry['bgpPeerIdentifier']][$entry['afi']] != $afi ||
                    $bgpPeersCache[$vrfName][$entry['bgpPeerIdentifier']][$entry['safi']] != $safi) {
                dbDelete(
                    'bgpPeers_cbgp',
                    '`device_id`=? AND `bgpPeerIdentifier`=? AND context_name=? AND afi=? AND safi=?',
                    [$device['device_id'], $address, $vrfName, $afi, $safi]
                );
            }
        }

        unset($bgpPeersCache);
        unset($bgpPeers);
        if ($vrp_bgp_peer_count > 0) {
            return; //Finish BGP discovery here, cause we collected data
        }
        // If not, we continue with standard BGP4 MIB
    }
}