snmp-node

This is a native SNMP library for Node.js. The purpose is to provide enough functionality to perform large scale monitoring of network equipment. Current features towards this end are:

• Full implementation of SNMPv2c, including 64 bit data types.
• Support for Get, GetNext and Set requests, with optimizations such as GetAll and GetSubtree.
• No unusual external dependencies, no non-JavaScript code.
• Very high performance, unlimited parallellism. (There are always limits. However, there are no arbitrary such imposed by this code and you at least won't run out of file descriptors.)
• De facto standards compliance. Generated packets are compared against Net-SNMP and should be identical in all relevant aspects.
• Well tested. Test coverage should be at or close to 100% for all important code paths.

It specifically does not include:

• Compatibility with SNMPv1, SNMPv2u or SNMPv3. These are (in order) deprecated, weird, and too complicated. Yes, it's an opinionated library.
• MIB parsing. Do this in your client app if it's necessary.

It's optimized for polling tens of thousands of counters on hundreds or thousands of hosts in a parallell manner. This is known to work (although performance might be limited by less than optimal SNMP agent implementations in random network gear).

Documentation

Installation

$ npm install snmp-node

Usage

Import

var snmp = require('snmp-node');

new Session(options)

Create a Session. The Session constructor, like most of the other functions, take an options object. The options passed to the Session will be the defaults for any subsequent function calls on that session, but can be overridden as needed. Useful parameters here are host, port and family.

// Create a Session with default settings.
var session = new snmp.Session();
 
// Create a Session with explicit default host, port, and community.
var session = new snmp.Session({ host: 'device.example.com', port: 161, community: 'special' });
 
// Create an IPv6 Session.
var session = new snmp.Session({ host: '2001:db8::42', family: 'udp6', community: 'private' });

The following options are recognized as properties in the options object. All can be specified in the Session constructor and optionally overridden at a later time by setting them in the option object to a method call.

For optimum performance when polling many hosts, create a session without specifying the host. Reuse this session for all hosts and specify the host on each get, getAll, etc.

• host: The host to send the request to. An resolvable name is allowed in addition to IP addresses. Default: 'localhost'.
• port: The UDP port number to send the request to. Default: 161.
• community: The SNMP community name. Default: 'public'.
• family: Address family to bind to. This is only used by the Session constructor since that is when the bind is done. It cannot be changed or overridden after construction. Default: 'udp4'. Valid values: 'udp4' or 'udp6'.
• timeouts: An array of timeout values. Values are times in milliseconds, the length of the array is the total number of transmissions that will occur. Default: [5000, 5000, 5000, 5000] (four attempts, with five seconds between each). A backoff can be implemented by timeouts along the lines of [ 1000, 2000, 4000, 8000 ]. Retransmissions can be disabled by using only a single timeout value: [ 5000 ].
• bindPort: UDP port used to bind the socket locally. Default: 0 (random port)
• msgReceived: A (message, rinfo) => {} function responsible to handle incoming messages and sending UDP responses back. If nothing is given here, the default implementation is used. This is useful if you want to implement custom logic in your application

VarBind objects

All of the get* functions return arrays of VarBind as the result to the callback. The VarBind objects have the following properties:

• oid: The OID they represent (in array form).
• type: The integer type code for the returned value.
• value: The value, in decoded form. This will be an integer for integer, gauge, counter and timetick types, a string for an octet string value, an array for array or IP number types.
• valueRaw: For octet string values, this is a raw Buffer representing the string.
• valueHex: For octet string values, this is a hex string representation of the value.
• sendStamp: The timestamp (in milliseconds) when the request was transmitted.
• receiveStamp: The timestamp (in milliseconds) when the response was received.

get(options, callback)

Perform a simple GetRequest. Options (in addition to the ones defined above for Session):

• oid: The OID to get. Example: [1, 3, 6, 1, 4, 1, 1, 2, 3, 4] or '.1.3.6.1.4.1.1.2.3.4'. Both forms are accepted, but the string form will need to be parsed to an array, slightly increasing CPU usage.

Will call the specified callback with an error object (null on success) and the varbind that was received.

session.get({ oid: [1, 3, 6, 1, 4, 1, 42, 1, 0] }, function (error, varbinds) {
    if (error) {
        console.log('Fail :(');
    } else {
        console.log(varbinds[0].oid + ' = ' + varbinds[0].value + ' (' + varbinds[0].type + ')');
    }
});

You can also specify host, community, etc explicitly.

session.get({ oid: [1, 3, 6, 1, 4, 1, 42, 1, 0], host: 'localhost', community: 'test' }, ...);

getNext(options, callback)

Perform a simple GetNextRequest. Options:

• oid: The OID to get. Example: [1, 3, 6, 1, 4, 1, 1, 2, 3, 4] or '.1.3.6.1.4.1.1.2.3.4'.

Will call the specified callback with an error object (null on success) and the varbind that was received.

session.getNext({ oid: [1, 3, 6, 1, 4, 1, 42, 1, 0] }, function (error, varbinds) {
    if (error) {
        console.log('Fail :(');
    } else {
        console.log(varbinds[0].oid + ' = ' + varbinds[0].value + ' (' + varbinds[0].type + ')');
    }
});

getAll(options, callback)

Perform repeated GetRequests to fetch all the required values. Multiple OIDs will get packed into as few GetRequest packets as possible to minimize roundtrip delays. Gets will be issued serially (not in parallell) to avoid flooding hosts. Options:

• oids: An array of OIDs to get. Example: [[1, 3, 6, 1, 4, 1, 1, 2, 3], [1, 3, 6, 1, 4, 1, 1, 2, 4]] or ['.1.3.6.1.4.1.1.2.3.4', '.1.3.6.1.4.1.2.3.4.5'].
• abortOnError: Whether to stop or continue when an error is encountered. Default: false.
• combinedTimeout: Timeout in milliseconds that the getAll() may take. Default: no timeout.

The callback will be called with an error object or a list of varbinds. If the options property abortOnError is false (default) any variables that couldn't be fetched will simply be omitted from the results. If it is true, the callback will be called with an error object on any failure. If the combinedTimeout is triggered, the callback is called with an error and the partial results.

var oids = [ [1, 3, 6, 1, 4, 1, 42, 1, 0], [1, 3, 6, 1, 4, 1, 42, 2, 0], ... ];
session.getAll({ oids: oids }, function (error, varbinds) {
    varbinds.forEach(function (vb) {
        console.log(vb.oid + ' = ' + vb.value + ' (' + vb.type + ')');
    });
});

getSubtree(options, callback)

Perform repeated GetNextRequests to fetch all values in the specified tree. Options:

• oid: The OID to get. Example: [1, 3, 6, 1, 4, 1, 1, 2, 3, 4] or '.1.3.6.1.4.1.1.2.3.4'.
• combinedTimeout: Timeout in milliseconds that the getSubtree() may take. Default: no timeout.

Will call the specified callback with an error object (null on success) and the list of varbinds that was fetched. If the combinedTimeout is triggered, the callback is called with an error and the partial results.

session.getSubtree({ oid: [1, 3, 6, 1, 4, 1, 42] }, function (error, varbinds) {
    if (error) {
        console.log('Fail :(');
    } else {
        varbinds.forEach(function (vb) {
            console.log(vb.oid + ' = ' + vb.value + ' (' + vb.type + ')');
        });
    }
});

set(options, callback)

Perform a simple SetRequest. Options:

• oid: The OID to perform the set on. Example: [1, 3, 6, 1, 4, 1, 1, 2, 3, 4] or '.1.3.6.1.4.1.1.2.3.4'.
• value: The value to set. Example: 42.
• type: The type of the value. Currently supports asn1ber.T.Integer (2), asn1ber.T.Gauge (66), asn1ber.T.IpAddress (64), asn1ber.T.OctetString (4) and asn1ber.T.Null (5). Example: 2.

Example:

session.set({ oid: [1, 3, 6, 1, 4, 1, 42, 1, 0], value: 42, type: 2 }, function (error, varbind) {
    if (error) {
        console.log('Fail :(');
    } else {
        console.log('The set is done.');
    }
});

If you're not really interested in the outcome of the set (and if you are, why aren't you using scripted telnet or ssh instead to begin with?), you can call it without a callback:

session.set({ oid: [1, 3, 6, 1, 4, 1, 42, 1, 0], value: 42, type: 2 });

close()

Cancels all outstanding requests and frees used OS resources. Outstanding requests will call their callback with the "Cancelled" error set.

Example:

session.close();

License

MIT