asnobject.java

snmp zip 包开发snmp协议

// NAME
//      $RCSfile: AsnObject.java,v $
// DESCRIPTION
//      [given below in javadoc format]
// DELTA
//      $Revision: 3.30 $
// CREATED
//      $Date: 2006/03/23 14:54:09 $
// 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>
 * original version by [e-mail] (Jordan Hargrave)
 */

/*
 * 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.io.*;
import java.util.*;
import uk.co.westhawk.snmp.util.*;

/**
 * This class represents the ASN.1 base class.
 * SMIv1 <a href="http://www.ietf.org/rfc/rfc1155.txt">RFC1155-SMI</a>.
 * SMIv2 <a href="http://www.ietf.org/rfc/rfc2578.txt">SNMPv2-SMI</a>.
 *
 * <p><pre>
 * &lt;ASN Object&gt; = &lt;type&gt; &lt;length&gt; &lt;ASN Object&gt;
 * or
 * &lt;ASN Object&gt; = &lt;type&gt; &lt;length&gt; &lt;value&gt;
 * </pre></p>
 *
 * @author <a href="mailto:[e-mail]">Tim Panton</a>
 * @version $Revision: 3.30 $ $Date: 2006/03/23 14:54:09 $
 */

public abstract class AsnObject extends Object implements SnmpConstants
{
    private static final String     version_id =
        "@(#)$Id: AsnObject.java,v 3.30 2006/03/23 14:54:09 birgit Exp $ Copyright Westhawk Ltd";

    /**
     * Indicates the level of debug printed. By default this is none
     * (0).
     * @see #setDebug(int)
     */
    public static int debug = 0;

    /** 
     * The type of object.
     */
    protected byte type;

    /** 
     * The starting position of the AsnObject in the SNMP sequence. That
     * is the position of the 'type' byte. 
     */
    protected int startPos = 0;

    /** 
     * The length of the header. That is the number of bytes of the 'type'
     * and 'length' fields. Since there are multiple valid encodings for
     * a given AsnObject, this length is not fixed!
     */
    protected int headerLength = 0; 

    /** 
     * The length of the actual contents. That is the same as the value of
     * the 'length' field.
     */
    protected int contentsLength = 0;

    /** 
     * Flag to signal the object is of a correct type.
     */
    protected boolean isCorrect = true;

    abstract void write (OutputStream out, int pos) 
    throws IOException, EncodingException;

    /**
     * Returns a string representation of the object.
     * @return The string
     */
    public abstract String toString();

/**
 * Sets the new, global level of debug information for the stack package.
 * The default value is zero, i.e. no debug info at all. All debug
 * messages are printed to System.out.
 * <p>
 * The following messages will appear when debug is &gt; (greater than):
 * <ul>
 * <li><code>0</code> - IOExceptions that won't be thrown to the user</li>
 * <li><code>1</code> - DecodingExceptions that won't be thrown to the user (received message with wrong SNMP version)</li>
 * <li><code>2</code> - DecodingExceptions when trying to decode traps</li>
 * <li><code>3</code> - processIncomingResponse errors: (corresponding Pdu cannot be found)</li> 
 * <li><code>4</code> - Discovery of EngineId, Timeline</li>
 * <li><code>5</code> - Receiving traps, version/host do not correspond</li>
 * <li><code>6</code> - Pdu messages, sending etc</li>
 * <li><code>10</code> - Asn decoding of incoming messages</li>
 * <li><code>12</code> - Transmitter messages, Socket messages</li>
 * <li><code>15</code> - Not so important IOExceptions, like InterruptedIOException</li>
 * </ul>
 * </p>
 *
 * @param newDebug the new debug value
 */
public static void setDebug(int newDebug)
{
    debug = newDebug;
}

    AsnObject AsnReadHeader(InputStream in) throws IOException
    {
        return AsnReadHeader(in, 0);
    }

    /**
     * @param pos The starting position, i.e. the pos the 'type' byte.
     */
    AsnObject AsnReadHeader(InputStream in, int pos) throws IOException
    {
        int len, got;
        AsnObject ret = null;
        int had = in.available();

        //Type byte
        type = (byte) in.read();
        if (type != -1)
        {
            len = getLengthPacket(in);
            int off = in.available();
            int headLength = had - off;

            got = 0;
            byte body[] = new byte[len];
            if (len > 0)
            {
                got = in.read(body, 0, len);
            }
            if (got > -1)
            {
                // Always decode, unless in.read returned an error 
                // (i.e. got == -1):
                //
                // 1.
                // If we haven't received all bytes (i.e. got < len)
                // we will still try and decode as much as we can:
                // Since body[] has the length 'len' (i.e. the
                // length according to the packet), it will be padded with
                // zero
                // 
                // 2.
                // If len was 0, got would have been been -1, but since
                // no read was performed, got is 0.
                // A len of 0 is a valid case however.

                ByteArrayInputStream buf = new ByteArrayInputStream(body);
                ret = AsnMakeMe(buf, type, len, pos, headLength);

                if (got != len)
                {
                    ret.isCorrect = false;
                    if (debug > 10)
                    {
                        System.out.println("\nAsnObject.AsnReadHeader():"
                            + " incorrect packet. Length = " + (int) len
                            + ", Got = " + got);
                    }
                }
            }
            else
            {
                if (debug > 10)
                {
                    System.out.println("\nAsnObject.AsnReadHeader(): Length = " 
                        + (int) len
                        + ", Got = " + got 
                        + ". Not processing any further.");
                }
            }
        }
        return ret;
    }


    AsnObject AsnMakeMe(InputStream in, byte t, int len, int pos, 
        int headLength) throws IOException
    {
        AsnObject me = this;
        type = t;

        switch (type)
        {
          case CONS_SEQ :
            me = new AsnSequence(in, len, (pos+headLength));
            break;
          case GET_REQ_MSG :
          case GETNEXT_REQ_MSG :
          case SET_REQ_MSG :
          case GETBULK_REQ_MSG :
          case INFORM_REQ_MSG :
          case GET_RSP_MSG :
          case GET_RPRT_MSG :
          case TRPV2_REQ_MSG :
            me = new AsnPduSequence(in, len, (pos+headLength));
            break;
          case TRP_REQ_MSG :
            me = new AsnTrapPduv1Sequence(in, len, (pos+headLength));
            break;
          case ASN_INTEGER :
            me = new AsnInteger(in, len);
            break;
          case TIMETICKS :
          case COUNTER :
          case GAUGE :
          case OBSOLETED_RFC1442_UINTEGER32 :
            me = new AsnUnsInteger(in, len);
            break;
          case COUNTER64 :
            me = new AsnUnsInteger64(in, len); // TODO test
            break;
          case ASN_OBJECT_ID :
            me = new AsnObjectId(in, len);
            break;
          case IPADDRESS :
          case ASN_OCTET_STR :
          case OPAQUE :
          case NSAP_ADDRESS :
            me = new AsnOctets(in, len);
            break;
          case ASN_NULL :
            me = new AsnNull(in, len);
            break;
          case SNMP_VAR_NOSUCHOBJECT:
          case SNMP_VAR_NOSUCHINSTANCE:
          case SNMP_VAR_ENDOFMIBVIEW:
            me = new AsnPrimitive(type);
            break;
          default :
            if (debug > 0)
            {
                System.out.println("AsnObject.AsnMakeMe():"
                    + " Bad Type 0x" + SnmpUtilities.toHex(type));
            }
            me = new AsnNull(in, len);
            me.isCorrect = false;
            break;
        }
        me.type = type;
        me.startPos = pos;
        me.headerLength = headLength;
        me.contentsLength = len;

        if (debug > 10)
        {
            System.out.println("AsnObject.AsnMakeMe():" 
                  + " headerLength = " + me.headerLength
                  + ", contentsLength = " + me.contentsLength);
            System.out.println("\ttype = 0x" 
                  + SnmpUtilities.toHex(type) 
                  + ", " + me.getRespTypeString()
                  + ", " + me.getClass().getName() 
                  + ": value = " + me.toString()
                  + ", startPos = " + me.startPos