Snmp4JTrapNotifier.java

//
// This file is part of the OpenNMS(R) Application.
//
// OpenNMS(R) is Copyright (C) 2005 The OpenNMS Group, Inc.  All rights reserved.
// OpenNMS(R) is a derivative work, containing both original code, included code and modified
// code that was published under the GNU General Public License. Copyrights for modified 
// and included code are below.
//
// OpenNMS(R) is a registered trademark of The OpenNMS Group, Inc.
//
// Modifications:
//
// 2008 Dec 29: Code and comment formatting, remove some obvious comments,
//              and make the logic in processVarBindAt a little more clear.
//              - dj@opennms.org
//
// Original code base Copyright (C) 1999-2001 Oculan Corp.  All rights reserved.
//
// 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 2 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, write to the Free Software
// Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
//
// For more information contact:
// OpenNMS Licensing       <license@opennms.org>
//     http://www.opennms.org/
//     http://www.opennms.com/
//
package org.infosec.ismp.snmp.snmp4j;

import java.net.InetAddress;

import org.infosec.ismp.snmp.SnmpObjId;
import org.infosec.ismp.snmp.SnmpValue;
import org.infosec.ismp.snmp.TrapIdentity;
import org.infosec.ismp.snmp.TrapInformation;
import org.infosec.ismp.snmp.TrapNotificationListener;
import org.infosec.ismp.snmp.TrapProcessor;
import org.infosec.ismp.snmp.TrapProcessorFactory;
import org.infosec.ismp.util.ThreadCategory;
import org.snmp4j.CommandResponder;
import org.snmp4j.CommandResponderEvent;
import org.snmp4j.MessageException;
import org.snmp4j.PDU;
import org.snmp4j.PDUv1;
import org.snmp4j.mp.StateReference;
import org.snmp4j.mp.StatusInformation;
import org.snmp4j.smi.Integer32;
import org.snmp4j.smi.IpAddress;
import org.snmp4j.smi.OID;
import org.snmp4j.smi.SMIConstants;
import org.snmp4j.smi.TimeTicks;
import org.snmp4j.smi.Variable;
import org.snmp4j.smi.VariableBinding;

public class Snmp4JTrapNotifier implements CommandResponder {

	private final TrapProcessorFactory m_trapProcessorFactory;
	private final TrapNotificationListener m_listener;

	public Snmp4JTrapNotifier(TrapNotificationListener listener,
			TrapProcessorFactory processorFactory) {
		m_listener = listener;
		m_trapProcessorFactory = processorFactory;
	}

	public static class Snmp4JV1TrapInformation extends TrapInformation {

		private final PDUv1 m_pdu;

		protected Snmp4JV1TrapInformation(InetAddress agent, String community,
				PDUv1 pdu, TrapProcessor trapProcessor) {
			super(agent, community, trapProcessor);
			m_pdu = pdu;
		}

		@Override
		protected InetAddress getTrapAddress() {
			return m_pdu.getAgentAddress().getInetAddress();
		}

		@Override
		protected String getVersion() {
			return "v1";
		}

		@Override
		protected int getPduLength() {
			return m_pdu.getVariableBindings().size();
		}

		@Override
		protected long getTimeStamp() {
			return m_pdu.getTimestamp();
		}

		@Override
		protected TrapIdentity getTrapIdentity() {
			return new TrapIdentity(SnmpObjId.get(m_pdu.getEnterprise()
					.getValue()), m_pdu.getGenericTrap(),
					m_pdu.getSpecificTrap());
		}

		protected VariableBinding getVarBindAt(int i) {
			return m_pdu.get(i);
		}

		@Override
		protected void processVarBindAt(int i) {
			SnmpObjId name = SnmpObjId.get(getVarBindAt(i).getOid().getValue());
			SnmpValue value = new Snmp4JValue(getVarBindAt(i).getVariable());
			processVarBind(name, value);
		}
	}

	public static class Snmp4JV2TrapInformation extends TrapInformation {
		/**
		 * The received PDU
		 */
		private final PDU m_pdu;

		/**
		 * The name of the PDU's type
		 */
		private final String m_pduTypeString;

		/**
		 * The snmp sysUpTime OID is the first varbind
		 */
		static final int SNMP_SYSUPTIME_OID_INDEX = 0;

		/**
		 * The snmp trap OID is the second varbind
		 */
		static final int SNMP_TRAP_OID_INDEX = 1;

		/**
		 * The sysUpTimeOID, which should be the first varbind in a V2 trap
		 */
		static final OID SNMP_SYSUPTIME_OID = new OID(".1.3.6.1.2.1.1.3.0");

		/**
		 * The sysUpTimeOID, which should be the first varbind in a V2 trap, but in
		 * the case of Extreme Networks only mostly
		 */
		static final OID EXTREME_SNMP_SYSUPTIME_OID = new OID(
				".1.3.6.1.2.1.1.3");

		/**
		 * The snmpTrapOID, which should be the second varbind in a V2 trap
		 */
		static final OID SNMP_TRAP_OID = new OID(".1.3.6.1.6.3.1.1.4.1.0");

		/**
		 * Constructs a new trap information instance that contains the sending
		 * agent, the community string, and the Protocol Data Unit.
		 * 
		 * @param agent
		 *            The sending agent's address
		 * @param community
		 *            The community string from the SNMP packet.
		 * @param pdu
		 *            The encapsulated Protocol Data Unit.
		 * @param trapProcessor The trap processor used to process the trap data
		 * 
		 */
		public Snmp4JV2TrapInformation(InetAddress agent, String community,
				PDU pdu, TrapProcessor trapProcessor) {
			super(agent, community, trapProcessor);
			m_pdu = pdu;
			m_pduTypeString = PDU.getTypeString(m_pdu.getType());
		}

		/**
		 * Returns the Protocol Data Unit that was encapsulated within the SNMP
		 * Trap message
		 */
		private PDU getPdu() {
			return m_pdu;
		}

		@Override
		protected int getPduLength() {
			return getPdu().size();
		}

		@Override
		protected long getTimeStamp() {

			if (log().isDebugEnabled()) {
				log().debug(
						"V2 " + m_pduTypeString + " first varbind value: "
								+ getVarBindAt(0).getVariable().toString());
			}

			switch (getVarBindAt(SNMP_SYSUPTIME_OID_INDEX).getVariable()
					.getSyntax()) {
			case SMIConstants.SYNTAX_TIMETICKS:
				log().debug(
						"V2 "
								+ m_pduTypeString
								+ " first varbind value is of type TIMETICKS (correct)");
				return ((TimeTicks) getVarBindAt(SNMP_SYSUPTIME_OID_INDEX)
						.getVariable()).getValue();
			case SMIConstants.SYNTAX_INTEGER32:
				log().debug(
						"V2 "
								+ m_pduTypeString
								+ " first varbind value is of type INTEGER, casting to TIMETICKS");
				return ((Integer32) getVarBindAt(SNMP_SYSUPTIME_OID_INDEX)
						.getVariable()).getValue();
			default:
				throw new IllegalArgumentException(
						"V2 "
								+ m_pduTypeString
								+ " does not have the required first varbind as TIMETICKS - cannot process "
								+ m_pduTypeString);
			}
		}

		@Override
		protected TrapIdentity getTrapIdentity() {
			OID snmpTrapOid = (OID) getVarBindAt(SNMP_TRAP_OID_INDEX)
					.getVariable();
			OID lastVarBindOid = getVarBindAt(getPduLength() - 1).getOid();
			Variable lastVarBindValue = getVarBindAt(getPduLength() - 1)
					.getVariable();
			return new TrapIdentity(SnmpObjId.get(snmpTrapOid.getValue()),
					SnmpObjId.get(lastVarBindOid.getValue()), new Snmp4JValue(
							lastVarBindValue));
		}

		@Override
		public InetAddress getTrapAddress() {
			return getAgentAddress();
		}

		protected VariableBinding getVarBindAt(int index) {
			return getPdu().get(index);
		}

		@Override
		protected String getVersion() {
			return "v2";
		}

		@Override
		protected void validate() {
			int pduType = getPdu().getType();
			if (pduType != PDU.TRAP && pduType != PDU.INFORM) {
				throw new IllegalArgumentException(
						"Received not SNMPv2 Trap|Inform from host "
								+ getTrapAddress() + " PDU Type = "
								+ PDU.getTypeString(getPdu().getType()));
			}

			if (log().isDebugEnabled()) {
				log().debug(
						"V2 " + m_pduTypeString + " numVars or pdu length: "
								+ getPduLength());
			}

			if (getPduLength() < 2) {
				throw new IllegalArgumentException(
						"V2 "
								+ m_pduTypeString
								+ " from "
								+ getTrapAddress()
								+ " IGNORED due to not having the required varbinds.  Have "
								+ getPduLength() + ", needed at least 2");
			}

			OID varBindName0 = getVarBindAt(0).getOid();
			OID varBindName1 = getVarBindAt(1).getOid();

			/*
			 * Modify the sysUpTime varbind OID to add the trailing 0 if it is
			 * missing, which is seen with some Extreme equipment.
			 */
			if (varBindName0.equals(EXTREME_SNMP_SYSUPTIME_OID)) {
				log().info(
						"V2 "
								+ m_pduTypeString
								+ " from "
								+ getTrapAddress()
								+ " has been corrected due to the sysUptime.0 varbind not having been sent with a trailing 0.\n\tVarbinds received are : "
								+ varBindName0 + " and " + varBindName1);
				varBindName0 = SNMP_SYSUPTIME_OID;
			}

			/*
			 * Confirm that the two required varbinds (sysUpTime and
			 * snmpTrapOID) are present and in that order.
			 */
			if ((!(varBindName0.equals(SNMP_SYSUPTIME_OID)))
					|| (!(varBindName1.equals(SNMP_TRAP_OID)))) {
				throw new IllegalArgumentException(
						"V2 "
								+ m_pduTypeString
								+ " from "
								+ getTrapAddress()
								+ " IGNORED due to not having the required varbinds.\n\tThe first varbind must be sysUpTime.0 and the second snmpTrapOID.0\n\tVarbinds received are : "
								+ varBindName0 + " and " + varBindName1);
			}
		}

		@Override
		protected void processVarBindAt(int i) {
			if (i == 0) {
				log().debug(
						"Skipping processing of varbind "
								+ i
								+ ": it is sysuptime and the first varbind, and is not processed as a parm per RFC2089");
			} else if (i == 1) {
				log().debug(
						"Skipping processing of varbind "
								+ i
								+ ": it is the trap OID and the second varbind, and is not processed as a parm per RFC2089");
			} else {
				SnmpObjId name = SnmpObjId.get(getVarBindAt(i).getOid()
						.getValue());
				SnmpValue value = new Snmp4JValue(getVarBindAt(i).getVariable());
				processVarBind(name, value);
			}
		}
	}

	@Override
	public void processPdu(CommandResponderEvent e) {
		PDU command = new PDU(e.getPDU());
		IpAddress addr = ((IpAddress) e.getPeerAddress());

		if (command != null) {
			if (command.getType() == PDU.INFORM) {
				PDU response = new PDU(command);
				response.setErrorIndex(0);
				response.setErrorStatus(0);
				response.setType(PDU.RESPONSE);
				StatusInformation statusInformation = new StatusInformation();
				StateReference ref = e.getStateReference();
				try {
					e.getMessageDispatcher().returnResponsePdu(
							e.getMessageProcessingModel(),
							e.getSecurityModel(), e.getSecurityName(),
							e.getSecurityLevel(), response,
							e.getMaxSizeResponsePDU(), ref, statusInformation);
					if (log().isDebugEnabled()) {
						log().debug(
								"Sent RESPONSE PDU to peer "
										+ addr
										+ " acknowledging receipt of INFORM (reqId="
										+ command.getRequestID() + ")");
					}
				} catch (MessageException ex) {
					log().error(
							"Error while sending RESPONSE PDU to peer " + addr
									+ ": " + ex.getMessage()
									+ "acknowledging receipt of INFORM (reqId="
									+ command.getRequestID() + ")");
				}
			}
		}

		if (e.getPDU() instanceof PDUv1) {
			m_listener.trapReceived(new Snmp4JV1TrapInformation(addr
					.getInetAddress(), new String(e.getSecurityName()),
					(PDUv1) e.getPDU(), m_trapProcessorFactory
							.createTrapProcessor()));
		} else {
			m_listener.trapReceived(new Snmp4JV2TrapInformation(addr
					.getInetAddress(), new String(e.getSecurityName()), e
					.getPDU(), m_trapProcessorFactory.createTrapProcessor()));
		}
	}

	private ThreadCategory log() {
		return ThreadCategory.getInstance(getClass());
	}
}