defaultusmagent.java

snmp zip 包开发snmp协议

// NAME
//      $RCSfile: DefaultUsmAgent.java,v $
// DESCRIPTION
//      [given below in javadoc format]
// DELTA
//      $Revision: 3.9 $
// CREATED
//      $Date: 2006/03/23 14:54:10 $
// COPYRIGHT
//      Westhawk Ltd
// TO DO
//

/*
 * Copyright (C) 2001 - 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 uk.co.westhawk.snmp.beans.UsmDiscoveryBean;

/**
 * This implementation of UsmAgent tries to discover the parameters by
 * doing the default USM discovery process on localhost. 
 *
 * <p>
 * Note that it is not guaranteed that the agent will allow discovery 
 * by itself. Also, if the SNMP agent reboots while the stack is
 * running, it will not pick up the new boots and time.
 * </p>
 *
 * <p>
 * Users are advised and encouraged to provide a better, more accurate
 * implementation of UsmAgent.
 * </p>
 *
 * <p>
 * See <a href="http://www.ietf.org/rfc/rfc3414.txt">SNMP-USER-BASED-SM-MIB</a>.
 * </p>
 * @see SnmpContextv3
 *
 * @author <a href="mailto:[e-mail]">Birgit Arkesteijn</a>
 * @version $Revision: 3.9 $ $Date: 2006/03/23 14:54:10 $
 */
public class DefaultUsmAgent implements UsmAgent
{
    static final String version_id =
        "@(#)$Id: DefaultUsmAgent.java,v 3.9 2006/03/23 14:54:10 birgit Exp $ Copyright Westhawk Ltd";

      /**
       * The default name of the local host, <em>localhost</em>.
       */
      public final static String LOCAL_HOST = "localhost";

      /**
       * The default port number of the local host, <em>161</em>.
       */
      public final static int LOCAL_PORT = 161;

      private SnmpContextv3Basis context;
      private String hostname;
      private String hostaddress;
      private int port;

public DefaultUsmAgent()
{
    try
    {
        setAgentName(LOCAL_HOST);
    }
    catch (java.net.UnknownHostException exc)
    {
        hostname = LOCAL_HOST;
        hostaddress = "127.0.0.1";
    }
    setAgentPort(LOCAL_PORT);
}

/**
 * Returns the authoritative SNMP Engine ID. If the discovery failed,
 * <em>null</em> will be returned.
 *
 * @return The Engine ID
 */
public String getSnmpEngineId()
{
    TimeWindow tWindow = TimeWindow.getCurrent();
    String engineId = tWindow.getSnmpEngineId(hostaddress, port);
    return engineId;
}

/**
 * Returns the authoritative Engine Boots. If the discovery failed,
 * <em>1</em> will be returned.
 *
 * @return The Engine Boots
 */
public int getSnmpEngineBoots()
{
    int boots = 1;
    TimeWindowNode node = null;
    TimeWindow tWindow = TimeWindow.getCurrent();
    String engineId = tWindow.getSnmpEngineId(hostaddress, port);
    if (engineId != null)
    {
        node = tWindow.getTimeLine(engineId);
    }
    if (node != null)
    {
        boots = node.getSnmpEngineBoots();
    }
    return boots;
}

/**
 * Returns the authoritative Engine Time. If the discovery failed,
 * <em>1</em> will be returned.
 *
 * @return The Engine Time
 */
public int getSnmpEngineTime()
{
    int time = 1;
    TimeWindowNode node = null;
    TimeWindow tWindow = TimeWindow.getCurrent();
    String engineId = tWindow.getSnmpEngineId(hostaddress, port);
    if (engineId != null)
    {
        node = tWindow.getTimeLine(engineId);
    }
    if (node != null)
    {
        time = node.getSnmpEngineTime();
    }
    return time;
}

/**
 * Sets the SNMP context. It will do a discovery if needed.
 */
public void setSnmpContext(SnmpContextv3Basis c) 
{
    context = c;
    try
    {
        discoverIfNeeded();
    }
    catch (PduException exc)
    {
        if (AsnObject.debug > 4)
        {
            System.out.println(getClass().getName() + ".setSnmpContext(): "
                + exc.getMessage()); 
        }
    }
    catch (java.io.IOException exc)
    {
        if (AsnObject.debug > 4)
        {
            System.out.println(getClass().getName() + ".setSnmpContext(): "
                + exc.getMessage()); 
        }
    }
}

/**
 * Sets my own hostname, i.e. the name of the agent or authoritative
 * engine. By default <em>localhost</em> is used.
 * Sets the hostaddress as well, using java.net.InetAddress.
 *
 * @see #LOCAL_HOST
 * @exception java.net.UnknownHostException Thrown when java.net.InetAddress cannot
 * resolve the name
 */
public void setAgentName(String host)
throws java.net.UnknownHostException
{
    hostname = host;
    java.net.InetAddress ipAddr = java.net.InetAddress.getByName(hostname);
    hostaddress = ipAddr.getHostAddress();
}

/**
 * Sets my own port number, i.e. the port number of the agent 
 * or authoritative engine. By default <em>161</em> is used.
 *
 * @see #LOCAL_PORT
 */
public void setAgentPort(int p)
{
    port = p;
}

/**
 * This discovers the USM timeliness of hostname and port as set by
 * setAgentName() and setAgentPort(), but with all the other details
 * taken from the SNMPv3 context.
 *
 * @see #setAgentName
 * @see #setAgentPort
 */
void discoverIfNeeded()
throws java.io.IOException, PduException
{
    uk.co.westhawk.snmp.beans.UsmDiscoveryBean discBean = null;
    boolean isNeeded = false;

    TimeWindow tWindow = TimeWindow.getCurrent();
    String engineId = tWindow.getSnmpEngineId(hostaddress, port);
    if (engineId == null)
    {
        isNeeded = true;
        discBean = new uk.co.westhawk.snmp.beans.UsmDiscoveryBean(hostname, 
              port, context.getBindAddress(), context.getTypeSocket());
    }

    if (context.isUseAuthentication())
    {
        if (isNeeded)
        {
            discBean.setAuthenticationDetails(context.getUserName(),
                context.getUserAuthenticationPassword(),
                context.getAuthenticationProtocol());
        }
        else if (tWindow.isTimeLineKnown(engineId) == false)
        {
            isNeeded = true;
            discBean = new uk.co.westhawk.snmp.beans.UsmDiscoveryBean(
                    hostname, port, context.getBindAddress(), 
                    context.getTypeSocket());
            discBean.setAuthenticationDetails(context.getUserName(),
                context.getUserAuthenticationPassword(),
                context.getAuthenticationProtocol());
        }

        if (isNeeded && context.isUsePrivacy())
        {
            discBean.setPrivacyDetails(context.getUserPrivacyPassword());
        }
    }

    if (isNeeded)
    {
        discBean.startDiscovery();
        discBean.freeResources();
    }
}

/**
 * @since 4_14
 */
public long getUsmStatsUnknownEngineIDs()
{
    return 0;
}

/**
 * @since 4_14
 */
public long getUsmStatsNotInTimeWindows()
{
    return 0;
}

}