node.d/snmp: snmpv3 support (#7802)

* node.d.plugin/node_modules: update net-snmp.js to the latest (snmp v3 support)

* node.d/snmp.node.js: create v3 session if snmp version is 3

* node.d/snmp/README.md: update

3 files changed, 3419 insertions, 1357 deletions

diff --git a/collectors/node.d.plugin/node_modules/net-snmp.js b/collectors/node.d.plugin/node_modules/net-snmp.js
index 484597dcb0..6b5b754ea4 100644
--- a/collectors/node.d.plugin/node_modules/net-snmp.js
+++ b/collectors/node.d.plugin/node_modules/net-snmp.js
@@ -1,66 +1,77 @@
-
 // Copyright 2013 Stephen Vickers <stephen.vickers.sv@gmail.com>
 // SPDX-License-Identifier: MIT
 
-var ber = require ("asn1-ber").Ber;
-var dgram = require ("dgram");
-var events = require ("events");
-var util = require ("util");
+var ber = require("asn1-ber").Ber;
+var dgram = require("dgram");
+var events = require("events");
+var util = require("util");
+var crypto = require("crypto");
+
+var DEBUG = false;
+
+var MAX_INT32 = 2147483647;
+
+function debug(line) {
+    if (DEBUG) {
+        console.debug(line);
+    }
+}
 
 /*****************************************************************************
  ** Constants
  **/
 
-function _expandConstantObject (object) {
-	var keys = [];
-	for (var key in object)
-		keys.push (key);
-	for (var i = 0; i < keys.length; i++)
-		object[object[keys[i]]] = parseInt (keys[i]);
+
+function _expandConstantObject(object) {
+    var keys = [];
+    for (var key in object)
+        keys.push(key);
+    for (var i = 0; i < keys.length; i++)
+        object[object[keys[i]]] = parseInt(keys[i]);
 }
 
 var ErrorStatus = {
-	0: "NoError",
-	1: "TooBig",
-	2: "NoSuchName",
-	3: "BadValue",
-	4: "ReadOnly",
-	5: "GeneralError",
-	6: "NoAccess",
-	7: "WrongType",
-	8: "WrongLength",
-	9: "WrongEncoding",
-	10: "WrongValue",
-	11: "NoCreation",
-	12: "InconsistentValue",
-	13: "ResourceUnavailable",
-	14: "CommitFailed",
-	15: "UndoFailed",
-	16: "AuthorizationError",
-	17: "NotWritable",
-	18: "InconsistentName"
-};
-
-_expandConstantObject (ErrorStatus);
+    0: "NoError",
+    1: "TooBig",
+    2: "NoSuchName",
+    3: "BadValue",
+    4: "ReadOnly",
+    5: "GeneralError",
+    6: "NoAccess",
+    7: "WrongType",
+    8: "WrongLength",
+    9: "WrongEncoding",
+    10: "WrongValue",
+    11: "NoCreation",
+    12: "InconsistentValue",
+    13: "ResourceUnavailable",
+    14: "CommitFailed",
+    15: "UndoFailed",
+    16: "AuthorizationError",
+    17: "NotWritable",
+    18: "InconsistentName"
+};
+
+_expandConstantObject(ErrorStatus);
 
 var ObjectType = {
-	1: "Boolean",
-	2: "Integer",
-	4: "OctetString",
-	5: "Null",
-	6: "OID",
-	64: "IpAddress",
-	65: "Counter",
-	66: "Gauge",
-	67: "TimeTicks",
-	68: "Opaque",
-	70: "Counter64",
-	128: "NoSuchObject",
-	129: "NoSuchInstance",
-	130: "EndOfMibView"
-};
-
-_expandConstantObject (ObjectType);
+    1: "Boolean",
+    2: "Integer",
+    4: "OctetString",
+    5: "Null",
+    6: "OID",
+    64: "IpAddress",
+    65: "Counter",
+    66: "Gauge",
+    67: "TimeTicks",
+    68: "Opaque",
+    70: "Counter64",
+    128: "NoSuchObject",
+    129: "NoSuchInstance",
+    130: "EndOfMibView"
+};
+
+_expandConstantObject(ObjectType);
 
 ObjectType.Integer32 = ObjectType.Integer;
 ObjectType.Counter32 = ObjectType.Counter;
@@ -68,132 +79,173 @@ ObjectType.Gauge32 = ObjectType.Gauge;
 ObjectType.Unsigned32 = ObjectType.Gauge32;
 
 var PduType = {
-	160: "GetRequest",
-	161: "GetNextRequest",
-	162: "GetResponse",
-	163: "SetRequest",
-	164: "Trap",
-	165: "GetBulkRequest",
-	166: "InformRequest",
-	167: "TrapV2",
-	168: "Report"
+    160: "GetRequest",
+    161: "GetNextRequest",
+    162: "GetResponse",
+    163: "SetRequest",
+    164: "Trap",
+    165: "GetBulkRequest",
+    166: "InformRequest",
+    167: "TrapV2",
+    168: "Report"
 };
 
-_expandConstantObject (PduType);
+_expandConstantObject(PduType);
 
 var TrapType = {
-	0: "ColdStart",
-	1: "WarmStart",
-	2: "LinkDown",
-	3: "LinkUp",
-	4: "AuthenticationFailure",
-	5: "EgpNeighborLoss",
-	6: "EnterpriseSpecific"
+    0: "ColdStart",
+    1: "WarmStart",
+    2: "LinkDown",
+    3: "LinkUp",
+    4: "AuthenticationFailure",
+    5: "EgpNeighborLoss",
+    6: "EnterpriseSpecific"
+};
+
+_expandConstantObject(TrapType);
+
+var SecurityLevel = {
+    1: "noAuthNoPriv",
+    2: "authNoPriv",
+    3: "authPriv"
+};
+
+_expandConstantObject(SecurityLevel);
+
+var AuthProtocols = {
+    "1": "none",
+    "2": "md5",
+    "3": "sha"
+};
+
+_expandConstantObject(AuthProtocols);
+
+var PrivProtocols = {
+    "1": "none",
+    "2": "des"
+};
+
+_expandConstantObject(PrivProtocols);
+
+var MibProviderType = {
+    "1": "Scalar",
+    "2": "Table"
 };
 
-_expandConstantObject (TrapType);
+_expandConstantObject(MibProviderType);
 
 var Version1 = 0;
 var Version2c = 1;
+var Version3 = 3;
+
+var Version = {
+    "1": Version1,
+    "2c": Version2c,
+    "3": Version3
+};
 
 /*****************************************************************************
  ** Exception class definitions
  **/
 
-function ResponseInvalidError (message) {
-	this.name = "ResponseInvalidError";
-	this.message = message;
-	Error.captureStackTrace(this, ResponseInvalidError);
+function ResponseInvalidError(message) {
+    this.name = "ResponseInvalidError";
+    this.message = message;
+    Error.captureStackTrace(this, ResponseInvalidError);
 }
-util.inherits (ResponseInvalidError, Error);
 
-function RequestInvalidError (message) {
-	this.name = "RequestInvalidError";
-	this.message = message;
-	Error.captureStackTrace(this, RequestInvalidError);
+util.inherits(ResponseInvalidError, Error);
+
+function RequestInvalidError(message) {
+    this.name = "RequestInvalidError";
+    this.message = message;
+    Error.captureStackTrace(this, RequestInvalidError);
 }
-util.inherits (RequestInvalidError, Error);
 
-function RequestFailedError (message, status) {
-	this.name = "RequestFailedError";
-	this.message = message;
-	this.status = status;
-	Error.captureStackTrace(this, RequestFailedError);
+util.inherits(RequestInvalidError, Error);
+
+function RequestFailedError(message, status) {
+    this.name = "RequestFailedError";
+    this.message = message;
+    this.status = status;
+    Error.captureStackTrace(this, RequestFailedError);
 }
-util.inherits (RequestFailedError, Error);
 
-function RequestTimedOutError (message) {
-	this.name = "RequestTimedOutError";
-	this.message = message;
-	Error.captureStackTrace(this, RequestTimedOutError);
+util.inherits(RequestFailedError, Error);
+
+function RequestTimedOutError(message) {
+    this.name = "RequestTimedOutError";
+    this.message = message;
+    Error.captureStackTrace(this, RequestTimedOutError);
 }
-util.inherits (RequestTimedOutError, Error);
+
+util.inherits(RequestTimedOutError, Error);
 
 /*****************************************************************************
  ** OID and varbind helper functions
  **/
 
-function isVarbindError (varbind) {
-	return !!(varbind.type == ObjectType.NoSuchObject
-	|| varbind.type == ObjectType.NoSuchInstance
-	|| varbind.type == ObjectType.EndOfMibView);
+function isVarbindError(varbind) {
+    return !!(varbind.type == ObjectType.NoSuchObject
+        || varbind.type == ObjectType.NoSuchInstance
+        || varbind.type == ObjectType.EndOfMibView);
 }
 
-function varbindError (varbind) {
-	return (ObjectType[varbind.type] || "NotAnError") + ": " + varbind.oid;
+function varbindError(varbind) {
+    return (ObjectType[varbind.type] || "NotAnError") + ": " + varbind.oid;
 }
 
-function oidFollowsOid (oidString, nextString) {
-	var oid = {str: oidString, len: oidString.length, idx: 0};
-	var next = {str: nextString, len: nextString.length, idx: 0};
-	var dotCharCode = ".".charCodeAt (0);
-
-	function getNumber (item) {
-		var n = 0;
-		if (item.idx >= item.len)
-			return null;
-		while (item.idx < item.len) {
-			var charCode = item.str.charCodeAt (item.idx++);
-			if (charCode == dotCharCode)
-				return n;
-			n = (n ? (n * 10) : n) + (charCode - 48);
-		}
-		return n;
-	}
-
-	while (1) {
-		var oidNumber = getNumber (oid);
-		var nextNumber = getNumber (next);
-
-		if (oidNumber !== null) {
-			if (nextNumber !== null) {
-				if (nextNumber > oidNumber) {
-					return true;
-				} else if (nextNumber < oidNumber) {
-					return false;
-				}
-			} else {
-				return true;
-			}
-		} else {
-			return true;
-		}
-	}
+function oidFollowsOid(oidString, nextString) {
+    var oid = {str: oidString, len: oidString.length, idx: 0};
+    var next = {str: nextString, len: nextString.length, idx: 0};
+    var dotCharCode = ".".charCodeAt(0);
+
+    function getNumber(item) {
+        var n = 0;
+        if (item.idx >= item.len)
+            return null;
+        while (item.idx < item.len) {
+            var charCode = item.str.charCodeAt(item.idx++);
+            if (charCode == dotCharCode)
+                return n;
+            n = (n ? (n * 10) : n) + (charCode - 48);
+        }
+        return n;
+    }
+
+    while (1) {
+        var oidNumber = getNumber(oid);
+        var nextNumber = getNumber(next);
+
+        if (oidNumber !== null) {
+            if (nextNumber !== null) {
+                if (nextNumber > oidNumber) {
+                    return true;
+                } else if (nextNumber < oidNumber) {
+                    return false;
+                }
+            } else {
+                return true;
+            }
+        } else {
+            return true;
+        }
+    }
 }
 
-function oidInSubtree (oidString, nextString) {
-	var oid = oidString.split (".");
-	var next = nextString.split (".");
+function oidInSubtree(oidString, nextString) {
+    var oid = oidString.split(".");
+    var next = nextString.split(".");
 
-	if (oid.length > next.length)
-		return false;
+    if (oid.length > next.length)
+        return false;
 
-	for (var i = 0; i < oid.length; i++) {
-		if (next[i] != oid[i])
-			return false;
-	}
+    for (var i = 0; i < oid.length; i++) {
+        if (next[i] != oid[i])
+            return false;
+    }
 
-	return true;
+    return true;
 }
 
 /**
@@ -207,1228 +259,3138 @@ function oidInSubtree (oidString, nextString) {
  ** an error since the integer is too large.
  **/
 
-function readInt (buffer) {
-	return readUint (buffer, true);
+function readInt(buffer) {
+    return readUint(buffer, true);
+}
+
+function readIpAddress(buffer) {
+    var bytes = buffer.readString(ObjectType.IpAddress, true);
+    if (bytes.length != 4)
+        throw new ResponseInvalidError("Length '" + bytes.length
+            + "' of IP address '" + bytes.toString("hex")
+            + "' is not 4");
+    var value = bytes[0] + "." + bytes[1] + "." + bytes[2] + "." + bytes[3];
+    return value;
 }
 
-function readUint (buffer, isSigned) {
-	buffer.readByte ();
-	var length = buffer.readByte ();
-	var value = 0;
-	var signedBitSet = false;
-
-	if (length > 5) {
-		 throw new RangeError ("Integer too long '" + length + "'");
-	} else if (length == 5) {
-		if (buffer.readByte () !== 0)
-			throw new RangeError ("Integer too long '" + length + "'");
-		length = 4;
-	}
-
-	for (var i = 0; i < length; i++) {
-		value *= 256;
-		value += buffer.readByte ();
-
-		if (isSigned && i <= 0) {
-			if ((value & 0x80) == 0x80)
-				signedBitSet = true;
-		}
-	}
-	
-	if (signedBitSet)
-		value -= (1 << (i * 8));
-
-	return value;
+function readUint(buffer, isSigned) {
+    buffer.readByte();
+    var length = buffer.readByte();
+    var value = 0;
+    var signedBitSet = false;
+
+    if (length > 5) {
+        throw new RangeError("Integer too long '" + length + "'");
+    } else if (length == 5) {
+        if (buffer.readByte() !== 0)
+            throw new RangeError("Integer too long '" + length + "'");
+        length = 4;
+    }
+
+    for (var i = 0; i < length; i++) {
+        value *= 256;
+        value += buffer.readByte();
+
+        if (isSigned && i <= 0) {
+            if ((value & 0x80) == 0x80)
+                signedBitSet = true;
+        }
+    }
+
+    if (signedBitSet)
+        value -= (1 << (i * 8));
+
+    return value;
 }
 
-function readUint64 (buffer) {
-	var value = buffer.readString (ObjectType.Counter64, true);
+function readUint64(buffer) {
+    var value = buffer.readString(ObjectType.Counter64, true);
 
-	return value;
+    return value;
 }
 
-function readVarbinds (buffer, varbinds) {
-	buffer.readSequence ();
-
-	while (1) {
-		buffer.readSequence ();
-		var oid = buffer.readOID ();
-		var type = buffer.peek ();
-
-		if (type == null)
-			break;
-
-		var value;
-
-		if (type == ObjectType.Boolean) {
-			value = buffer.readBoolean ();
-		} else if (type == ObjectType.Integer) {
-			value = readInt (buffer);
-		} else if (type == ObjectType.OctetString) {
-			value = buffer.readString (null, true);
-		} else if (type == ObjectType.Null) {
-			buffer.readByte ();
-			buffer.readByte ();
-			value = null;
-		} else if (type == ObjectType.OID) {
-			value = buffer.readOID ();
-		} else if (type == ObjectType.IpAddress) {
-			var bytes = buffer.readString (ObjectType.IpAddress, true);
-			if (bytes.length != 4)
-				throw new ResponseInvalidError ("Length '" + bytes.length
-						+ "' of IP address '" + bytes.toString ("hex")
-						+ "' is not 4");
-			value = bytes[0] + "." + bytes[1] + "." + bytes[2] + "." + bytes[3];
-		} else if (type == ObjectType.Counter) {
-			value = readUint (buffer);
-		} else if (type == ObjectType.Gauge) {
-			value = readUint (buffer);
-		} else if (type == ObjectType.TimeTicks) {
-			value = readUint (buffer);
-		} else if (type == ObjectType.Opaque) {
-			value = buffer.readString (ObjectType.Opaque, true);
-		} else if (type == ObjectType.Counter64) {
-			value = readUint64 (buffer);
-		} else if (type == ObjectType.NoSuchObject) {
-			buffer.readByte ();
-			buffer.readByte ();
-			value = null;
-		} else if (type == ObjectType.NoSuchInstance) {
-			buffer.readByte ();
-			buffer.readByte ();
-			value = null;
-		} else if (type == ObjectType.EndOfMibView) {
-			buffer.readByte ();
-			buffer.readByte ();
-			value = null;
-		} else {
-			throw new ResponseInvalidError ("Unknown type '" + type
-					+ "' in response");
-		}
-
-		varbinds.push ({
-			oid: oid,
-			type: type,
-			value: value
-		});
-	}
+function readVarbinds(buffer, varbinds) {
+    buffer.readSequence();
+
+    while (1) {
+        buffer.readSequence();
+        if (buffer.peek() != ObjectType.OID)
+            break;
+        var oid = buffer.readOID();
+        var type = buffer.peek();
+
+        if (type == null)
+            break;
+
+        var value;
+
+        if (type == ObjectType.Boolean) {
+            value = buffer.readBoolean();
+        } else if (type == ObjectType.Integer) {
+            value = readInt(buffer);
+        } else if (type == ObjectType.OctetString) {
+            value = buffer.readString(null, true);
+        } else if (type == ObjectType.Null) {
+            buffer.readByte();
+            buffer.readByte();
+            value = null;
+        } else if (type == ObjectType.OID) {
+            value = buffer.readOID();
+        } else if (type == ObjectType.IpAddress) {
+            var bytes = buffer.readString(ObjectType.IpAddress, true);
+            if (bytes.length != 4)
+                throw new ResponseInvalidError("Length '" + bytes.length
+                    + "' of IP address '" + bytes.toString("hex")
+                    + "' is not 4");
+            value = bytes[0] + "." + bytes[1] + "." + bytes[2] + "." + bytes[3];
+        } else if (type == ObjectType.Counter) {
+            value = readUint(buffer);
+        } else if (type == ObjectType.Gauge) {
+            value = readUint(buffer);
+        } else if (type == ObjectType.TimeTicks) {
+            value = readUint(buffer);
+        } else if (type == ObjectType.Opaque) {
+            value = buffer.readString(ObjectType.Opaque, true);
+        } else if (type == ObjectType.Counter64) {
+            value = readUint64(buffer);
+        } else if (type == ObjectType.NoSuchObject) {
+            buffer.readByte();
+            buffer.readByte();
+            value = null;
+        } else if (type == ObjectType.NoSuchInstance) {
+            buffer.readByte();
+            buffer.readByte();
+            value = null;
+        } else if (type == ObjectType.EndOfMibView) {
+            buffer.readByte();
+            buffer.readByte();
+            value = null;
+        } else {
+            throw new ResponseInvalidError("Unknown type '" + type
+                + "' in response");
+        }
+
+        varbinds.push({
+            oid: oid,
+            type: type,
+            value: value
+        });
+    }
 }
 
-function writeUint (buffer, type, value) {
-	var b = new Buffer (4);
-	b.writeUInt32BE (value, 0);
-	buffer.writeBuffer (b, type);
+function writeUint(buffer, type, value) {
+    var b = Buffer.alloc(4);
+    b.writeUInt32BE(value, 0);
+    buffer.writeBuffer(b, type);
 }
 
-function writeUint64 (buffer, value) {
-	buffer.writeBuffer (value, ObjectType.Counter64);
+function writeUint64(buffer, value) {
+    buffer.writeBuffer(value, ObjectType.Counter64);
 }
 
-function writeVarbinds (buffer, varbinds) {
-	buffer.startSequence ();
-	for (var i = 0; i < varbinds.length; i++) {
-		buffer.startSequence ();
-		buffer.writeOID (varbinds[i].oid);
-
-		if (varbinds[i].type && varbinds[i].hasOwnProperty("value")) {
-			var type = varbinds[i].type;
-			var value = varbinds[i].value;
-
-			if (type == ObjectType.Boolean) {
-				buffer.writeBoolean (value ? true : false);
-			} else if (type == ObjectType.Integer) { // also Integer32
-				buffer.writeInt (value);
-			} else if (type == ObjectType.OctetString) {
-				if (typeof value == "string")
-					buffer.writeString (value);
-				else
-					buffer.writeBuffer (value, ObjectType.OctetString);
-			} else if (type == ObjectType.Null) {
-				buffer.writeNull ();
-			} else if (type == ObjectType.OID) {
-				buffer.writeOID (value);
-			} else if (type == ObjectType.IpAddress) {
-				var bytes = value.split (".");
-				if (bytes.length != 4)
-					throw new RequestInvalidError ("Invalid IP address '"
-							+ value + "'");
-				buffer.writeBuffer (new Buffer (bytes), 64);
-			} else if (type == ObjectType.Counter) { // also Counter32
-				writeUint (buffer, ObjectType.Counter, value);
-			} else if (type == ObjectType.Gauge) { // also Gauge32 & Unsigned32
-				writeUint (buffer, ObjectType.Gauge, value);
-			} else if (type == ObjectType.TimeTicks) {
-				writeUint (buffer, ObjectType.TimeTicks, value);
-			} else if (type == ObjectType.Opaque) {
-				buffer.writeBuffer (value, ObjectType.Opaque);
-			} else if (type == ObjectType.Counter64) {
-				writeUint64 (buffer, value);
-			} else {
-				throw new RequestInvalidError ("Unknown type '" + type
-						+ "' in request");
-			}
-		} else {
-			buffer.writeNull ();
-		}
-
-		buffer.endSequence ();
-	}
-	buffer.endSequence ();
+function writeVarbinds(buffer, varbinds) {
+    buffer.startSequence();
+    for (var i = 0; i < varbinds.length; i++) {
+        buffer.startSequence();
+        buffer.writeOID(varbinds[i].oid);
+
+        if (varbinds[i].type && varbinds[i].hasOwnProperty("value")) {
+            var type = varbinds[i].type;
+            var value = varbinds[i].value;
+
+            if (type == ObjectType.Boolean) {
+                buffer.writeBoolean(value ? true : false);
+            } else if (type == ObjectType.Integer) { // also Integer32
+                buffer.writeInt(value);
+            } else if (type == ObjectType.OctetString) {
+                if (typeof value == "string")
+                    buffer.writeString(value);
+                else
+                    buffer.writeBuffer(value, ObjectType.OctetString);
+            } else if (type == ObjectType.Null) {
+                buffer.writeNull();
+            } else if (type == ObjectType.OID) {
+                buffer.writeOID(value);
+            } else if (type == ObjectType.IpAddress) {
+                var bytes = value.split(".");
+                if (bytes.length != 4)
+                    throw new RequestInvalidError("Invalid IP address '"
+                        + value + "'");
+                buffer.writeBuffer(Buffer.from(bytes), 64);
+            } else if (type == ObjectType.Counter) { // also Counter32
+                writeUint(buffer, ObjectType.Counter, value);
+            } else if (type == ObjectType.Gauge) { // also Gauge32 & Unsigned32
+                writeUint(buffer, ObjectType.Gauge, value);
+            } else if (type == ObjectType.TimeTicks) {
+                writeUint(buffer, ObjectType.TimeTicks, value);
+            } else if (type == ObjectType.Opaque) {
+                buffer.writeBuffer(value, ObjectType.Opaque);
+            } else if (type == ObjectType.Counter64) {
+                writeUint64(buffer, value);
+            } else if (type == ObjectType.EndOfMibView) {
+                buffer.writeByte(130);
+                buffer.writeByte(0);
+            } else {
+                throw new RequestInvalidError("Unknown type '" + type
+                    + "' in request");
+            }
+        } else {
+            buffer.writeNull();
+        }
+
+        buffer.endSequence();
+    }
+    buffer.endSequence();
 }
 
 /*****************************************************************************
  ** PDU class definitions
  **/
 
-var SimplePdu = function (id, varbinds, options) {
-	this.id = id;
-	this.varbinds = varbinds;
-	this.options = options || {};
+var SimplePdu = function () {
 };
 
 SimplePdu.prototype.toBuffer = function (buffer) {
-	buffer.startSequence (this.type);
+    buffer.startSequence(this.type);
 
-	buffer.writeInt (this.id);
-	buffer.writeInt ((this.type == PduType.GetBulkRequest)
-			? (this.options.nonRepeaters || 0)
-			: 0);
-	buffer.writeInt ((this.type == PduType.GetBulkRequest)
-			? (this.options.maxRepetitions || 0)
-			: 0);
+    buffer.writeInt(this.id);
+    buffer.writeInt((this.type == PduType.GetBulkRequest)
+        ? (this.options.nonRepeaters || 0)
+        : 0);
+    buffer.writeInt((this.type == PduType.GetBulkRequest)
+        ? (this.options.maxRepetitions || 0)
+        : 0);
 
-	writeVarbinds (buffer, this.varbinds);
+    writeVarbinds(buffer, this.varbinds);
 
-	buffer.endSequence ();
+    buffer.endSequence();
 };
 
-var GetBulkRequestPdu = function () {
-	this.type = PduType.GetBulkRequest;
-	GetBulkRequestPdu.super_.apply (this, arguments);
-};
+SimplePdu.prototype.initializeFromVariables = function (id, varbinds, options) {
+    this.id = id;
+    this.varbinds = varbinds;
+    this.options = options || {};
+    this.contextName = (options && options.context) ? options.context : "";
+}
 
-util.inherits (GetBulkRequestPdu, SimplePdu);
+SimplePdu.prototype.initializeFromBuffer = function (reader) {
+    this.type = reader.peek();
+    reader.readSequence();
+
+    this.id = reader.readInt();
+    this.nonRepeaters = reader.readInt();
+    this.maxRepetitions = reader.readInt();
+
+    this.varbinds = [];
+    readVarbinds(reader, this.varbinds);
 
-var GetNextRequestPdu = function () {
-	this.type = PduType.GetNextRequest;
-	GetNextRequestPdu.super_.apply (this, arguments);
 };
 
-util.inherits (GetNextRequestPdu, SimplePdu);
+SimplePdu.prototype.getResponsePduForRequest = function () {
+    var responsePdu = GetResponsePdu.createFromVariables(this.id, [], {});
+    if (this.contextEngineID) {
+        responsePdu.contextEngineID = this.contextEngineID;
+        responsePdu.contextName = this.contextName;
+    }
+    return responsePdu;
+};
+
+SimplePdu.createFromVariables = function (pduClass, id, varbinds, options) {
+    var pdu = new pduClass(id, varbinds, options);
+    pdu.id = id;
+    pdu.varbinds = varbinds;
+    pdu.options = options || {};
+    pdu.contextName = (options && options.context) ? options.context : "";
+    return pdu;
+};
 
-var GetResponsePdu = function (buffer) {
-	this.type = PduType.GetResponse;
+var GetBulkRequestPdu = function () {
+    this.type = PduType.GetBulkRequest;
+    GetBulkRequestPdu.super_.apply(this, arguments);
+};
 
-	buffer.readSequence (this.type);
+util.inherits(GetBulkRequestPdu, SimplePdu);
 
-	this.id = buffer.readInt ();
+GetBulkRequestPdu.createFromBuffer = function (reader) {
+    var pdu = new GetBulkRequestPdu();
+    pdu.initializeFromBuffer(reader);
+    return pdu;
+};
 
-	this.errorStatus = buffer.readInt ();
-	this.errorIndex = buffer.readInt ();
+var GetNextRequestPdu = function () {
+    this.type = PduType.GetNextRequest;
+    GetNextRequestPdu.super_.apply(this, arguments);
+};
 
-	this.varbinds = [];
+util.inherits(GetNextRequestPdu, SimplePdu);
 
-	readVarbinds (buffer, this.varbinds);
+GetNextRequestPdu.createFromBuffer = function (reader) {
+    var pdu = new GetNextRequestPdu();
+    pdu.initializeFromBuffer(reader);
+    return pdu;
 };
 
 var GetRequestPdu = function () {
-	this.type = PduType.GetRequest;
-	GetRequestPdu.super_.apply (this, arguments);
+    this.type = PduType.GetRequest;
+    GetRequestPdu.super_.apply(this, arguments);
+};
+
+util.inherits(GetRequestPdu, SimplePdu);
+
+GetRequestPdu.createFromBuffer = function (reader) {
+    var pdu = new GetRequestPdu();
+    pdu.initializeFromBuffer(reader);
+    return pdu;
 };
 
-util.inherits (GetRequestPdu, SimplePdu);
+GetRequestPdu.createFromVariables = function (id, varbinds, options) {
+    var pdu = new GetRequestPdu();
+    pdu.initializeFromVariables(id, varbinds, options);
+    return pdu;
+};
 
 var InformRequestPdu = function () {
-	this.type = PduType.InformRequest;
-	InformRequestPdu.super_.apply (this, arguments);
+    this.type = PduType.InformRequest;
+    InformRequestPdu.super_.apply(this, arguments);
 };
 
-util.inherits (InformRequestPdu, SimplePdu);
+util.inherits(InformRequestPdu, SimplePdu);
+
+InformRequestPdu.createFromBuffer = function (reader) {
+    var pdu = new InformRequestPdu();
+    pdu.initializeFromBuffer(reader);
+    return pdu;
+};
 
 var SetRequestPdu = function () {
-	this.type = PduType.SetRequest;
-	SetRequestPdu.super_.apply (this, arguments);
+    this.type = PduType.SetRequest;
+    SetRequestPdu.super_.apply(this, arguments);
+};
+
+util.inherits(SetRequestPdu, SimplePdu);
+
+SetRequestPdu.createFromBuffer = function (reader) {
+    var pdu = new SetRequestPdu();
+    pdu.initializeFromBuffer(reader);
+    return pdu;
 };
 
-util.inherits (SetRequestPdu, SimplePdu);
+var TrapPdu = function () {
+    this.type = PduType.Trap;
+};
 
-var TrapPdu = function (typeOrOid, varbinds, options) {
-	this.type = PduType.Trap;
+TrapPdu.prototype.toBuffer = function (buffer) {
+    buffer.startSequence(this.type);
 
-	this.agentAddr = options.agentAddr || "127.0.0.1";
-	this.upTime = options.upTime;
+    buffer.writeOID(this.enterprise);
+    buffer.writeBuffer(Buffer.from(this.agentAddr.split(".")),
+        ObjectType.IpAddress);
+    buffer.writeInt(this.generic);
+    buffer.writeInt(this.specific);
+    writeUint(buffer, ObjectType.TimeTicks,
+        this.upTime || Math.floor(process.uptime() * 100));
 
-	if (typeof typeOrOid == "string") {
-		this.generic = TrapType.EnterpriseSpecific;
-		this.specific = parseInt (typeOrOid.match (/\.(\d+)$/)[1]);
-		this.enterprise = typeOrOid.replace (/\.(\d+)$/, "");
-	} else {
-		this.generic = typeOrOid;
-		this.specific = 0;
-		this.enterprise = "1.3.6.1.4.1";
-	}
+    writeVarbinds(buffer, this.varbinds);
 
-	this.varbinds = varbinds;
+    buffer.endSequence();
 };
 
-TrapPdu.prototype.toBuffer = function (buffer) {
-	buffer.startSequence (this.type);
+TrapPdu.createFromBuffer = function (reader) {
+    var pdu = new TrapPdu();
+    reader.readSequence();
+
+    pdu.enterprise = reader.readOID();
+    pdu.agentAddr = readIpAddress(reader);
+    pdu.generic = reader.readInt();
+    pdu.specific = reader.readInt();
+    pdu.upTime = readUint(reader)
+
+    pdu.varbinds = [];
+    readVarbinds(reader, pdu.varbinds);
+
+    return pdu;
+};
 
-	buffer.writeOID (this.enterprise);
-	buffer.writeBuffer (new Buffer (this.agentAddr.split (".")),
-			ObjectType.IpAddress);
-	buffer.writeInt (this.generic);
-	buffer.writeInt (this.specific);
-	writeUint (buffer, ObjectType.TimeTicks,
-			this.upTime || Math.floor (process.uptime () * 100));
+TrapPdu.createFromVariables = function (typeOrOid, varbinds, options) {
+    var pdu = new TrapPdu();
+    pdu.agentAddr = options.agentAddr || "127.0.0.1";
+    pdu.upTime = options.upTime;
 
-	writeVarbinds (buffer, this.varbinds);
+    if (typeof typeOrOid == "string") {
+        pdu.generic = TrapType.EnterpriseSpecific;
+        pdu.specific = parseInt(typeOrOid.match(/\.(\d+)$/)[1]);
+        pdu.enterprise = typeOrOid.replace(/\.(\d+)$/, "");
+    } else {
+        pdu.generic = typeOrOid;
+        pdu.specific = 0;
+        pdu.enterprise = "1.3.6.1.4.1";
+    }
 
-	buffer.endSequence ();
+    pdu.varbinds = varbinds;
+
+    return pdu;
 };
 
 var TrapV2Pdu = function () {
-	this.type = PduType.TrapV2;
-	TrapV2Pdu.super_.apply (this, arguments);
+    this.type = PduType.TrapV2;
+    TrapV2Pdu.super_.apply(this, arguments);
+};
+
+util.inherits(TrapV2Pdu, SimplePdu);
+
+TrapV2Pdu.createFromBuffer = function (reader) {
+    var pdu = new TrapV2Pdu();
+    pdu.initializeFromBuffer(reader);
+    return pdu;
+};
+
+TrapV2Pdu.createFromVariables = function (id, varbinds, options) {
+    var pdu = new TrapV2Pdu();
+    pdu.initializeFromVariables(id, varbinds, options);
+    return pdu;
+};
+
+var SimpleResponsePdu = function () {
+};
+
+SimpleResponsePdu.prototype.toBuffer = function (writer) {
+    writer.startSequence(this.type);
+
+    writer.writeInt(this.id);
+    writer.writeInt(this.errorStatus || 0);
+    writer.writeInt(this.errorIndex || 0);
+    writeVarbinds(writer, this.varbinds);
+    writer.endSequence();
+
 };
 
-util.inherits (TrapV2Pdu, SimplePdu);
+SimpleResponsePdu.prototype.initializeFromBuffer = function (reader) {
+    reader.readSequence(this.type);
+
+    this.id = reader.readInt();
+    this.errorStatus = reader.readInt();
+    this.errorIndex = reader.readInt();
+
+    this.varbinds = [];
+    readVarbinds(reader, this.varbinds);
+};
+
+SimpleResponsePdu.prototype.initializeFromVariables = function (id, varbinds, options) {
+    this.id = id;
+    this.varbinds = varbinds;
+    this.options = options || {};
+};
+
+var GetResponsePdu = function () {
+    this.type = PduType.GetResponse;
+    GetResponsePdu.super_.apply(this, arguments);
+};
+
+util.inherits(GetResponsePdu, SimpleResponsePdu);
+
+GetResponsePdu.createFromBuffer = function (reader) {
+    var pdu = new GetResponsePdu();
+    pdu.initializeFromBuffer(reader);
+    return pdu;
+};
+
+GetResponsePdu.createFromVariables = function (id, varbinds, options) {
+    var pdu = new GetResponsePdu();
+    pdu.initializeFromVariables(id, varbinds, options);
+    return pdu;
+};
+
+var ReportPdu = function () {
+    this.type = PduType.Report;
+    ReportPdu.super_.apply(this, arguments);