ifxtable.java

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//
// This file is part of the OpenNMS(R) Application.
//
// OpenNMS(R) is Copyright (C) 2002-2003 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:
//
// 2003 Jan 31: Cleaned up some unused imports.
//
// 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       <[e-mail]>
//      http://www.opennms.org/
//      http://www.opennms.com/
//
// Tab Size = 8
//
// IfXTable.java,v 1.1.1.1 2001/11/11 17:34:36 ben Exp
//

package org.opennms.netmgt.capsd.snmp;

import java.util.ArrayList;
import java.util.List;

import org.apache.log4j.Category;
import org.opennms.core.utils.ThreadCategory;
import org.opennms.netmgt.utils.Signaler;
import org.opennms.protocols.snmp.SnmpHandler;
import org.opennms.protocols.snmp.SnmpInt32;
import org.opennms.protocols.snmp.SnmpObjectId;
import org.opennms.protocols.snmp.SnmpPduBulk;
import org.opennms.protocols.snmp.SnmpPduPacket;
import org.opennms.protocols.snmp.SnmpPduRequest;
import org.opennms.protocols.snmp.SnmpSMI;
import org.opennms.protocols.snmp.SnmpSession;
import org.opennms.protocols.snmp.SnmpSyntax;
import org.opennms.protocols.snmp.SnmpVarBind;

/**
 * <P>
 * The IfXTable uses a SnmpSession to collect the entries in the remote agent's
 * interface extensions table. It implements the SnmpHandler to receive
 * notifications and handle errors associated with the data collection. Data is
 * collected using a series of GETNEXT PDU request to walk multiple parts of the
 * interface table at once. The number of SNMP packets should not exceed the
 * number of interface + 1, assuming no lost packets or error conditions occur.
 * </P>
 * 
 * @author <A HREF="mailto:[e-mail]">Mike </A>
 * @author <A HREF="mailto:[e-mail]">Weave </A>
 * @author <A HREF="http://www.opennms.org/">OpenNMS </A>
 * 
 * @version 1.1.1.1
 * 
 * @see <A HREF="http://www.ietf.org/rfc/rfc2233.txt">RFC2233 </A>
 */
public final class IfXTable implements SnmpHandler {
    //
    // Used to convert decimal to hex
    //
    private static final char[] m_hexDigit = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F' };

    /**
     * <P>
     * The list of interfaces from the remote's interface extensions table. The
     * list contains a set of IfXTableEntry objects that were collected from the
     * remote host.
     * </P>
     * 
     * @see IfXTableEntry
     */
    private List m_entries;

    /**
     * <P>
     * Flag indicating if query was successful or if the collection failed.
     * </P>
     */
    private boolean m_error;

    /**
     * <P>
     * Used to synchronize the class to ensure that the session has finished
     * collecting data before the value of success or failure is set, and
     * control is returned to the caller.
     * </P>
     */
    private Signaler m_signal;

    /**
     * <P>
     * Used to generate the proper command for fetching the SNMP data from the
     * agent (via GETBULK for version 2 or GETNEXT for version 1.
     * </P>
     */
    private int m_version;

    /**
     * <P>
     * The request id associated with the GetNext PDU generated to retrieve the
     * number of interfaces associated with the remote host.
     * </P>
     */
    private int m_ifNumberRequestId;

    /**
     * <P>
     * This will be the OID where the information should cut off from the return
     * packet from the GETBULK command.
     * </P>
     */
    private SnmpObjectId m_stopAt = null;

    /**
     * <P>
     * Used for storing the ifNumber variable from the MIB, the number of
     * interfaces a device possesses.
     * </P>
     */
    private int m_ifNumber;

    /**
     * <P>
     * Used as a temporary storage space for all the data collected from the
     * SNMP response packets for SNMP v2. After receiving all the data, the
     * information will be sorted so that it mimics the SNMP v1 data storage;
     * one map per interface containing all the necessary MIB values.
     * </P>
     */
    private SnmpVarBind[] tempStorage = null;

    /**
     * <P>
     * For SNMPv1 used to keep track of the number of SNMP response packets
     * received.
     * 
     * For SNMPv2 used to keep track of the total number of varbinds received in
     * SNMP response packets.
     * 
     * For both SNMPv1 and SNMPv2 this value is used to determine when all the
     * necessary SNMP data has been retrieved.
     * </P>
     */
    private int m_responses = 0;

    /**
     * <P>
     * The default constructor is marked as private and will always throw an
     * exception. This is done to disallow the constructor to be called. Since
     * any instance of this class must have an SnmpSession and Signaler to
     * properly work, the correct constructor must be used.
     * </P>
     * 
     * @exception java.lang.UnsupportedOperationException
     *                Always thrown from this method since it is not supported.
     * 
     * @see #IfXTable(SnmpSession, Signaler)
     * 
     */
    private IfXTable() throws UnsupportedOperationException {
        throw new UnsupportedOperationException("Default constructor not supported!");
    }

    /**
     * <P>
     * Constructs an IfXTable object that is used to collect the interface
     * elements from the remote agent. Once all the interfaces are collected, or
     * there is an error in the collection the signaler object is <EM>notified
     * </EM> to inform other threads.
     * </P>
     * 
     * @param session
     *            The session with the remote agent.
     * @param signaler
     *            The object to notify waiters.
     * 
     * @see IfXTableEntry
     */
    public IfXTable(SnmpSession session, Signaler signaler) {
        m_signal = signaler;
        m_entries = new ArrayList(2); // not synchronized.
        m_error = false;

        m_version = SnmpSMI.SNMPV1;
        m_stopAt = IfXTableEntry.stop_oid();

        // first process, attain ifNumber.
        SnmpPduRequest pdu = IfXTableEntry.getIfNumberPdu();
        m_ifNumberRequestId = pdu.getRequestId();
        ThreadCategory.getInstance(getClass()).debug("IfXTable: ifNumber retrieval pdu request id: " + m_ifNumberRequestId);

        session.send(pdu, this);
    }

    /**
     * <P>
     * Constructs an IfXTable object that is used to collect the interface
     * elements from the remote agent. Once all the interfaces are collected, or
     * there is an error in the collection the signaler object is <EM>notified
     * </EM> to inform other threads.
     * </P>
     * 
     * @param session
     *            The session with the remote agent.
     * @param signaler
     *            The object to notify waiters.
     * @param version
     *            SNMP version to use
     * 
     * @see IfXTableEntry
     */
    public IfXTable(SnmpSession session, Signaler signaler, int version) {
        m_signal = signaler;
        m_entries = new ArrayList(2); // not synchronized.
        m_error = false;

        m_version = version;
        m_stopAt = IfXTableEntry.stop_oid();

        // first process, attain ifNumber.
        SnmpPduRequest pdu = IfXTableEntry.getIfNumberPdu();
        m_ifNumberRequestId = pdu.getRequestId();
        ThreadCategory.getInstance(getClass()).debug("IfXTable: ifNumber retrieval pdu request id: " + m_ifNumberRequestId);
        session.send(pdu, this);
    }

    /**
     * <P>
     * Returns the success or failure code for collection of the data.
     * </P>
     */
    public boolean failed() {
        return m_error;
    }

    /**
     * <P>
     * Returns the list of entry maps that can be used to access all the
     * information about the interface extensions table.
     * </P>
     * 
     * @return The list of ifXTableEntry maps.
     */
    public List getEntries() {
        return m_entries;
    }

    /**
     * <P>
     * This method is used to process received SNMP PDU packets from the remote
     * agent. The method is part of the SnmpHandler interface and will be
     * invoked when a PDU is successfully decoded. The method is passed the
     * receiving session, the PDU command, and the actual PDU packet.
     * </P>
     * 
     * <P>
     * When all the data has been received from the session the signaler object,
     * initialized in the constructor, is signaled. In addition, the receiving
     * instance will call notifyAll() on itself at the same time.
     * </P>
     * 
     * <P>
     * For SNMP version 2 devices, all the received data enters a temporary
     * array. After the collecting process, the method sorts the data so that
     * each interface has its own map.
     * </P>
     * 
     * @param session
     *            The SNMP Session that received the PDU
     * @param command
     *            The command contained in the received pdu
     * @param pdu
     *            The actual received PDU.
     * 
     */
    public void snmpReceivedPdu(SnmpSession session, int command, SnmpPduPacket pdu) {
        boolean doNotify = true;

        // lookup the category
        //
        Category log = ThreadCategory.getInstance(getClass());

        if (command != SnmpPduPacket.RESPONSE) {
            m_error = true;
        } else {
            //
            // Check for error stored in request pdu
            //
            int errStatus = ((SnmpPduRequest) pdu).getErrorStatus();
            if (errStatus != SnmpPduPacket.ErrNoError) {
                m_error = true;
            } else {
                // Is this the response to our request to retrieve ifNumber?
                // If so, begin gathering all the MIB data for the device
                if (pdu.getRequestId() == m_ifNumberRequestId) {
                    // Check for v2 error in varbind
                    SnmpVarBind vb = pdu.getVarBindAt(0);
                    SnmpObjectId ifNumberOid = new SnmpObjectId(".1.3.6.1.2.1.2.1");
                    if (!ifNumberOid.isRootOf(vb.getName())) {
                        m_error = true;