pdu.java

snmp zip 包开发snmp协议

// NAME
//      $RCSfile: Pdu.java,v $
// DESCRIPTION
//      [given below in javadoc format]
// DELTA
//      $Revision: 3.29 $
// CREATED
//      $Date: 2006/02/09 14:30:19 $
// COPYRIGHT
//      Westhawk Ltd
// TO DO
//

/*
 * Copyright (C) 1995, 1996 by West Consulting BV
 *
 * Permission to use, copy, modify, and distribute this software
 * for any purpose and without fee is hereby granted, provided
 * that the above copyright notices appear in all copies and that
 * both the copyright notice and this permission notice appear in
 * supporting documentation.
 * This software is provided "as is" without express or implied
 * warranty.
 * author <a href="mailto:[e-mail]">Tim Panton</a>
 */

/*
 * Copyright (C) 1996 - 2006 by Westhawk Ltd
 * <a href="www.westhawk.co.uk">www.westhawk.co.uk</a>
 *
 * Permission to use, copy, modify, and distribute this software
 * for any purpose and without fee is hereby granted, provided
 * that the above copyright notices appear in all copies and that
 * both the copyright notice and this permission notice appear in
 * supporting documentation.
 * This software is provided "as is" without express or implied
 * warranty.
 * author <a href="mailto:[e-mail]">Tim Panton</a>
 */


package uk.co.westhawk.snmp.stack;
import java.util.*;
import java.io.*;

import uk.co.westhawk.snmp.util.*;

/**
 * This class represents the ASN PDU object, this is the equivalent of
 * a GetRequest PDU.
 *
 * @author <a href="mailto:[e-mail]">Tim Panton</a>
 * @version $Revision: 3.29 $ $Date: 2006/02/09 14:30:19 $
 */
public abstract class Pdu extends Observable 
{
    private static final String     version_id =
        "@(#)$Id: Pdu.java,v 3.29 2006/02/09 14:30:19 birgit Exp $ Copyright Westhawk Ltd";

    protected Vector    reqVarbinds = null;
    protected Vector    respVarbinds = null;

    private final static String TIMED_OUT = "Timed out";
    private final static String [] errorStrings =
    {
        "No error",
        "Value too big error",
        "No such name error",
        "Bad value error",
        "Read only error",
        "General error",
        "No access error",
        "Wrong type error",
        "Wrong length error",
        "Wrong encoding error",
        "Wrong value error",
        "No creation error",
        "Inconsistent value error",
        "Resource unavailable error",
        "Commit failed error",
        "Undo failed error",
        "Authorization error",
        "Not writable error",
        "Inconsistent name error",
    };

    private static int  next_id = 1;
    private static final String NEXT_ID_LOCK="";
    
    private int retry_intervals[] = {500,1000,2000,5000,5000};

    protected byte[]    encodedPacket = null;
    protected SnmpContextBasisFace context;
    protected boolean   added = false;
    protected byte      msg_type;

    int                 req_id;
    protected Integer   snmpv3MsgId = null;
    protected int       errstat;
    protected int       errind;

    private Transmitter trans = null;
    private int         retries;
    protected boolean   answered;
    private boolean     got = false;
    private boolean     isTimedOut;
    private PduException respException = null;

/**
 * The value of the response is set. This will be called by
 * Pdu.fillin().
 */
protected void new_value(int n, varbind res) {}

/**
 * This method notifies all observers.
 * This will be called by Pdu.fillin().
 *
 * <p>
 * The Object to the update() method of the Observer will be a varbind, 
 * unless an exception occurred. 
 * In the case of an exception, that exception will be passed.
 * So watch out casting!
 * </p>
 */
protected void tell_them() 
{
    notifyObservers();
}

/** 
 * Constructor.
 *
 * @param con The context of the PDU
 * @see SnmpContext
 * @see SnmpContextv2c
 * @see SnmpContextv3
 */
public Pdu(SnmpContextBasisFace con) 
{
    context = con;

    // TODO: would not work if we ever were to send response or report!
    // TODO: We would have to set the req_id!

    // Added NEXT_ID_LOCK on suggestion of 
    // Victor Kirk <[e-mail]> 
    synchronized(NEXT_ID_LOCK)
    {
        req_id  = next_id++; 
    }
    errstat = AsnObject.SNMP_ERR_NOERROR;
    errind  = 0x00;
    reqVarbinds = new Vector(1,1);
    setMsgType(AsnObject.GET_REQ_MSG);
    isTimedOut = false;

    // if it is not set to false, PDUs that do not receive a response
    // will not be filled in properly.
    answered = false; 
}

/**
 * Returns the context of this PDU.
 * @return The context
 */
public SnmpContextBasisFace getContext()
{
    return context;
}

/** 
 * Sets the retry intervals of the PDU. The length of the array
 * corresponds with the number of retries. Each entry in the array
 * is the number of milliseconds of each try.
 *
 * <p>
 * If used, please set before sending!
 * </p>
 *
 * The default is {500, 1000, 2000, 5000, 5000}.
 * It is good practice to make the interval bigger with each retry,
 * if the numbers are the same the chance of collision is higher.
 *
 * @param rinterval The interval in msec of each retry
 */
public void setRetryIntervals(int rinterval[])
{
    retry_intervals = rinterval;
}

/** 
 * Sends the PDU.
 * Note that all properties of the context have to be set before this
 * point.
 */
public boolean send() throws java.io.IOException, PduException
{
    return send(errstat, errind);
}

/** 
 * Sends the PDU. This method accommodates the GetBulk request.
 *
 * @param error_status The value of the error_status field.
 * @param error_index The value of the error_index field.
 * @see #send()
 */
protected boolean send(int error_status, int error_index) 
throws java.io.IOException, PduException
{
    if (added == false)
    {
        // Moved this statement from the constructor because it
        // conflicts with the way the SnmpContextXPool works.
        added = context.addPdu(this);
    }
    Enumeration vbs = reqVarbinds.elements();
    encodedPacket = context.encodePacket(msg_type, req_id, error_status, 
        error_index, vbs, snmpv3MsgId);
    addToTrans();
    return added;  
}

/**
 * Adds the PDU to its transmitter. The transmitter is the thread that
 * will be sent the PDU and then waits for the answer.
 *
 * @see #send
 */
protected void addToTrans()
{
    if (added && (trans != null))
    {
        // thanks to Ian Dowse <[e-mail]> for synchronisation 
        synchronized(trans) 
        {
            trans.setPdu(this);
            trans.stand();
        }
    }
}

/**
 * Sends the actual packet and updates the retries.
 *
 * @see AbstractSnmpContext#sendPacket(byte[] p)
 */
protected boolean sendme() 
{
    context.sendPacket(encodedPacket);
    retries ++;

    if (AsnObject.debug > 6)
    {
        System.out.println(getClass().getName() + ".sendme(): Sent Pdu reqId " +req_id + ", retries "+retries);
    }
    return (retries > 3);
}


/** 
 * Sends the PDU.
 * For backwards compatibility only. Please use send() instead.
 * The community name will be passed to the SnmpContext. If using
 * SnmpContextv3, the community name will be ignored.
 *
 * @param com The community name of the PDU in SNMPv1 and SNMPv2c.
 * @deprecated Community name has moved to SnmpContext. Use {@link SnmpContext#setCommunity(String)}.
 *
 * @see SnmpContext#setCommunity
 * @see #send
 */
public boolean send(String com) throws java.io.IOException, PduException
{
    if (context instanceof SnmpContext)
    {
        ((SnmpContext)context).setCommunity(com);
    }
    return send();
}

/** 
 * Adds an OID (object identifier) to the PDU. The OID indicates which
 * MIB variable we request for or which MIB variable should be set.
 *
 * @param oid The oid 
 * @see #addOid(varbind)
 * @see varbind
 */
public void addOid(String oid) 
{
    varbind vb = new varbind(oid);
    addOid(vb);
}

/** 
 * Adds an OID (object identifier) to the PDU. The OID indicates which
 * MIB variable we request for or which MIB variable should be set.
 *
 * @param oid The oid 
 * @see #addOid(varbind)
 * @see varbind
 * @since 4_12
 */
public void addOid(AsnObjectId oid) 
{
    varbind vb = new varbind(oid);
    addOid(vb);
}

/** 
 * Adds an OID (object identifier) to the PDU and the value that has
 * to be set. This method has moved from SetPdu to this class in version 4_12.
 *
 * @param oid The oid 
 * @param val The value 
 * @see Pdu#addOid
 * @see varbind
 * @since 4_12
 */
public void addOid(String oid, AsnObject val) 
{
    varbind vb = new varbind(oid, val);
    addOid(vb);
}

/** 
 * Adds an OID (object identifier) to the PDU and the value that has
 * to be set. 
 *
 * <p>
 * Thanks to Eli Bishop ([e-mail]) for the suggestion.
 * </p>
 *
 * @param oid The oid 
 * @param val The value 
 * @see Pdu#addOid
 * @see varbind
 * @since 4_12
 */
public void addOid(AsnObjectId oid, AsnObject val) 
{
    varbind vb = new varbind(oid, val);
    addOid(vb);
}

/** 
 * Adds an OID (object identifier) to the PDU. 
 *
 * @param var The varbind 
 * @see #addOid(String)
 */
public void addOid(varbind var)
{
    reqVarbinds.addElement(var);
}

/**
 * Returns a copy of the varbinds used to build the request.
 *
 * @return the request varbinds of this PDU.
 */
public varbind[] getRequestVarbinds()
{
    int sz = reqVarbinds.size();
    varbind[] arr = new varbind[sz];
    reqVarbinds.copyInto(arr);
    return arr;
}

/**
 * Returns a copy of the varbinds received in the response.
 * If there was no response (yet), null will be returned.
 *
 * @return the response varbinds of this PDU.
 * @exception PduException An agent or decoding exception occurred
 * whilst receiving the response.
 *
 * @see #getErrorStatus
 * @see #notifyObservers
 */
public varbind[] getResponseVarbinds() throws PduException
{
    if (respException != null)
    {
        throw respException;
    }

    varbind[] arr = null;
    if (respVarbinds != null)
    {
        int sz = respVarbinds.size();
        arr = new varbind[sz];
        respVarbinds.copyInto(arr);
    }
    return arr;
}

private void dump(Vector v, varbind[] array)
{
    int sz = v.size();
    System.out.println("Vector: ");
    for (int i=0; i<sz; i++)
    {
        System.out.println("\t" + v.elementAt(i));
    }
    System.out.println("Array: ");
    for (int i=0; i<array.length; i++)
    {
        System.out.println("\t" + array[i]);
    }
    System.out.println("--");
}

void setResponseException(PduException exc)
{
    if (AsnObject.debug > 6)
    {
        System.out.println(getClass().getName() + ".setResponseException(): " + exc.getMessage());
    }
    respException = exc;
}

/** 
 * Returns the request id of the PDU.
 *
 * @return The ID
 */
public int getReqId() 
{
    return req_id;
}

/** 
 * Returns the error index.
 * The error index indicates which of the OIDs went wrong.
 *
 * @return the error index
 * @see #getErrorStatus
 */
public int getErrorIndex()
{
    return errind;
}

/** 
 * Returns the error status as indicated by the error-status field in
 * the reponse PDU. The error index will indicated which OID caused the
 * error.
 * In case of a decoding exception the error status
 * will be set to one of the decoding errors:
 * <ul>
 *   <li>
 * <code>SnmpConstants.SNMP_ERR_DECODING_EXC</code>.
 *   </li>
 *   <li>
 * <code>SnmpConstants.SNMP_ERR_DECODINGASN_EXC</code>.
 *   </li>
 *   <li>
 * <code>SnmpConstants.SNMP_ERR_DECODINGPKTLNGTH_EXC</code>.
 *   </li>
 * </ul>
 *
 * <p>
 * The actual exception will be passed to your 
 * <code>update(Observable ob, Object arg)</code>
 * method via the the parameter 
 * <code>arg</code>.
 * </p>
 *
 * @return the error status
 * @see #notifyObservers
 * @see #getResponseVarbinds
 * @see SnmpConstants#SNMP_ERR_NOERROR
 * @see SnmpConstants#SNMP_ERR_DECODING_EXC
 * @see SnmpConstants#SNMP_ERR_DECODINGASN_EXC
 * @see SnmpConstants#SNMP_ERR_DECODINGPKTLNGTH_EXC
 * @see #getErrorStatusString
 * @see #getErrorIndex
 */