domotz-remote-pawn/src/commands/snmp/getNative.js

Domotz Agent

/** This file is part of Domotz Agent.
 * Copyright (C) 2016  Domotz UK LLP
 *
 * Domotz Agent 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.
 *
 * Domotz Agent 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 Domotz Agent.  If not, see <http://www.gnu.org/licenses/>.
 **/

const TYPE_INTEGER = 2;
const TYPE_OID = 6;

function convertOIDS(oids) {
    var convertedOIDS = [];
    for (var i in oids) {
        convertedOIDS[i] = oids[i]
            .split('.')
            .filter(function (s) {
                return s.length > 0;
            })
            .map(function (s) {
                return parseInt(s, 10);
            });
    }
    return convertedOIDS;
}

function convertHexNumber(hexValue) {
    if (hexValue === undefined || hexValue === null) {
        return null;
    }
    var number = parseInt(hexValue, 16);
    var maxValue = Math.pow(2, (hexValue.length / 2) * 8);
    if (number > maxValue / 2 - 1) {
        number = number - maxValue;
    }
    return number;
}

var snmpGetNative = function (message, resourceLocator) {
    var myConsole = resourceLocator.log.decorateLogs();
    myConsole.info('SNMP_GET_NATIVE - (%s)', JSON.stringify(message));
    var snmpNative = resourceLocator.snmpNative;
    var cmdUtils = resourceLocator.utils.command;
    var snmpCommon = resourceLocator.snmpCommon;

    var cid = message.correlationId;
    var options = message.payload;

    var oidsMapping = cmdUtils.extractFromOptions(options, 'oids', {});
    var host = options.host;
    var community = options.community;

    var oids = snmpCommon.extractOids(oidsMapping);
    var transformer = message.customTransformer ? message.customTransformer : snmpCommon.transformer;

    // Comparison to null is mandatory because snmp.Version1 = 0
    if (options.version == null) {
        //jshint ignore:line
        options.version = snmpNative.Versions.SNMPv2c;
    }

    function extractOidsFromVarbinds(varbinds) {
        myConsole.info('SNMP_GET_NATIVE - (%s): Got response - number of returned oids: %s', cid, varbinds.length);
        var values = {};
        varbinds.forEach(function (vb) {
            var val;
            if (vb.type === TYPE_INTEGER) {
                val = convertHexNumber(vb.valueHex);
            } else if (vb.type === TYPE_OID) {
                val = vb.value.join('.').replace(/(.NaN).*/i, '');
            } else {
                val = vb.value;
            }
            var response_oid = vb.oid.join('.');
            var value = transformer(oidsMapping[response_oid])(val);
            values[response_oid] = value;
        });
        return { oids: values };
    }

    return {
        execute: function (callback) {
            var callbackCalled = false;
            var responseCallback = function (error, varbinds) {
                var response;
                if (error) {
                    myConsole.debug('SNMP_GET_NATIVE - (%s): SNMP error received: %s', cid, error);
                    response = { error: error };
                } else {
                    if (varbinds !== null && varbinds !== undefined) {
                        response = extractOidsFromVarbinds(varbinds);
                    } else {
                        response = { error: 'invalid SNMP response ' };
                    }
                }
                myConsole.debug('SNMP_GET_NATIVE - (%s): command execution concluded, yielding result: %s', cid, JSON.stringify(response));
                try {
                    snmpNativeSession.close();
                } catch (error) {
                    myConsole.error('SNMP_GET_NATIVE - cannot close session: ' + error);
                } finally {
                    if (!callbackCalled) {
                        callbackCalled = true;
                        callback(response);
                    }
                }
            };

            myConsole.debug('SNMP_NATIVE_GET - (%s): Sending SNMP get request to host %s for oids: %s', cid, host, JSON.stringify(oids));
            var snmpNativeSession = new snmpNative.Session(options);

            snmpNativeSession.on('error', function (error) {
                var errorMessage = error.toString();
                myConsole.error('SNMP_GET_NATIVE - (socket error) %s', errorMessage);
                try {
                    snmpNativeSession.close();
                } catch (error) {
                    myConsole.error('SNMP_GET_NATIVE - cannot close session: ' + error);
                } finally {
                    if (!callbackCalled) {
                        callbackCalled = true;
                        callback({ error: errorMessage });
                    }
                }
            });
            snmpNativeSession.getAll({ oids: convertOIDS(oids) }, responseCallback);
        },
        describe: function () {
            return cid + ' - snmpGetNative - ' + host + ' - ' + JSON.stringify(oids);
        },
    };
};

module.exports.command = snmpGetNative;
module.exports.convertOIDS = convertOIDS;
module.exports.convertHexNumber = convertHexNumber;