用snmp4j开发网管应用(二) -- 使用snmp4j

SNMP协议还算简单

其实针对协议的开发我们只要知道协议的内容,然后架起Socket服务器,然后用字符串拼出协议内容格式的字符串,使用Socket进行通信就好了。

针对协议的开源包主要把这些过程封装了。比如SNMP协议。

我们只需要针对PDU对象编程,然后SNMP4j就会把PDU对象转化为SNMP4j协议的格式,进行BER编码,然后传输,最后解码,再翻译为PDU对象。

先看一下SNMP协议要传输的内容:

http://www.cnpaf.net/Class/SNMP/200408/43.html

这个文章中说的很全和好了。接下来就是用SNMP4J协议的jar包来完成各个功能。

http://www.snmp4j.org/html/download.html

在这个网址中下载最新的SNMP4J的jar包,顺便可以把SNMP4J-Agent-2.2-Instrumentation-Guide.pdf 这个文档描述了对Agent进行开发。SNMP4J把开发包分为了两个,一个SNMP4J.jar主要负责get,trap,set,一个是SNMP4J-Agent.jar主要负责作为一个网元被管理。

 

1 首先说一下怎么开发一个Agent.

 需要用到两个配置文件bc和cfg文件,已经上传到bc_cfg.zip中

大概的代码为:

 

import java.io.File;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import org.snmp4j.agent.BaseAgent;
import org.snmp4j.agent.CommandProcessor;
import org.snmp4j.agent.DuplicateRegistrationException;
import org.snmp4j.agent.io.ImportModes;
import org.snmp4j.agent.mo.DefaultMOTable;
import org.snmp4j.agent.mo.MOTableRow;
import org.snmp4j.agent.mo.snmp.RowStatus;
import org.snmp4j.agent.mo.snmp.SnmpCommunityMIB;
import org.snmp4j.agent.mo.snmp.SnmpNotificationMIB;
import org.snmp4j.agent.mo.snmp.SnmpTargetMIB;
import org.snmp4j.agent.mo.snmp.StorageType;
import org.snmp4j.agent.mo.snmp.VacmMIB;
import org.snmp4j.agent.security.MutableVACM;
import org.snmp4j.mp.MPv3;
import org.snmp4j.security.SecurityLevel;
import org.snmp4j.security.SecurityModel;
import org.snmp4j.security.USM;
import org.snmp4j.smi.Integer32;
import org.snmp4j.smi.OID;
import org.snmp4j.smi.OctetString;
import org.snmp4j.smi.Variable;

public class MyAgent extends BaseAgent {
	private List<DefaultMOTable> moTables = new ArrayList<DefaultMOTable>();
	private String community;
	
	protected MyAgent(File bootCounterFile, File configFile, List<DefaultMOTable> moTables, String community) {
		super(bootCounterFile, configFile, new CommandProcessor(new OctetString(MPv3.createLocalEngineID())));
		this.moTables = moTables;
		this.community = community;
	}
	
	@Override
	protected void registerManagedObjects() {
		try {
			for (DefaultMOTable table : moTables) {
				server.register(table, null);
			}
		} catch (DuplicateRegistrationException e) {
			e.printStackTrace();
		}
	}
    
	public void startUp(){
		try {
			this.init();
		} catch (IOException e) {
			e.printStackTrace();
		}
		this.loadConfig(ImportModes.REPLACE_CREATE);
		this.addShutdownHook();
		this.getServer().addContext(new OctetString(community));
		this.finishInit();
		this.run();
		this.sendColdStartNotification();
	}
	
	/**
	 * to set community
	 */
	@Override
	protected void addCommunities(SnmpCommunityMIB communityMIB) {
		Variable[] com2sec = new Variable[] {
				new OctetString(community),              		// community name
				new OctetString("cpublic"),              	// security name
				getAgent().getContextEngineID(),        	// local engine ID
				new OctetString(community),              		// default context name
				new OctetString(),                      	// transport tag
				new Integer32(StorageType.nonVolatile), 	// storage type
				new Integer32(RowStatus.active)         	// row status
		};
		MOTableRow row =
			communityMIB.getSnmpCommunityEntry().createRow(
					new OctetString("public2public").toSubIndex(true), com2sec);
		communityMIB.getSnmpCommunityEntry().addRow(row);

	}
}
  •       主要的代码是需要继承BaseAgent
  • 需要设置community
  • 需要注册Table,这个注册中的内容将是供给get和walk的内容。
  • 可以从MIB直接构建Agent,可能需要的包为:mibble-mibs是能够独MIB结构的

2. Trap Receiver

import java.io.IOException;
import java.util.logging.Logger;
import org.snmp4j.MessageDispatcherImpl;
import org.snmp4j.Snmp;
import org.snmp4j.TransportMapping;
import org.snmp4j.mp.MPv2c;
import org.snmp4j.smi.Address;
import org.snmp4j.smi.GenericAddress;
import org.snmp4j.smi.UdpAddress;
import org.snmp4j.transport.DefaultUdpTransportMapping;
import org.snmp4j.util.MultiThreadedMessageDispatcher;
import org.snmp4j.util.ThreadPool;
import com.prince.snmp.tool.Command;
import com.prince.snmp.tool.util.Configure;
import com.prince.snmp.tool.util.Const;

/**
 * 构建一个多线程的Trap Receiver
 * @author wangzijian
 *
 */
public class SnmpReceiver implements Command{
	private final Logger log = Logger.getLogger(SnmpReceiver.class.getName());

	@Override
	public void startUp() throws IOException {
		log.info("Snmp Trap Receiver Start");
		log.info("listened on " + Configure.getInstance().getUdpTrapIpPort());
		ThreadPool pool = ThreadPool.create(Const.THREAD_POOL_NAME, Const.AGENT_THREAD_NUM);
		MultiThreadedMessageDispatcher dispatcher = new MultiThreadedMessageDispatcher(pool, new MessageDispatcherImpl());
		Address listenAddress = GenericAddress.parse(Configure.getInstance().getUdpTrapIpPort());
		TransportMapping transport = new DefaultUdpTransportMapping((UdpAddress) listenAddress);
		// 构建SNMP,并且使其开始监听
		Snmp snmp = new Snmp(dispatcher, transport);
        snmp.getMessageDispatcher().addMessageProcessingModel(new MPv2c());
        snmp.listen();
        snmp.addCommandResponder(new CommandResponderImpl());
	}
}

 

package com.prince.snmp.tool.receiver;

import java.util.List;
import java.util.logging.Logger;
import org.snmp4j.CommandResponder;
import org.snmp4j.CommandResponderEvent;
import org.snmp4j.PDU;
import org.snmp4j.smi.OID;
import org.snmp4j.smi.VariableBinding;

public class CommandResponderImpl implements CommandResponder {
	private final Logger log = Logger.getLogger(CommandResponderImpl.class.getName());
	
	@Override
	public void processPdu(CommandResponderEvent event) {
		PDU pdu = event.getPDU();
		if(PDU.TRAP == pdu.getType()){
			operate(pdu);
		}else{
			log.info("pdu method is:" + pdu.getType() + " not a trap");
		}
		
	}

	private void operate(PDU pdu) {
		List<VariableBinding> bindings = pdu.getBindingList(new OID(".1"));
		
		for (VariableBinding binding : bindings) {
			System.out.println(binding.getOid() + "====" + binding.getVariable().toString());
		}
	}
}

 

  •  需要一个多线程的服务器MultiThreadedMessageDispatcher
  • 还需要一个处理类 CommandResponderImpl  snmp.addCommandResponder
  • 在处理类中能够得到PDU,这个类不只可以作为Receiver还能够开发为Agent,但是需要自己来写很多逻辑,还有可能用到文件或者内存数据库

3. send trap

     

package com.prince.snmp.tool.trap;

import java.io.IOException;
import java.lang.reflect.InvocationTargetException;
import java.util.List;
import java.util.Vector;
import org.snmp4j.CommunityTarget;
import org.snmp4j.PDU;
import org.snmp4j.Snmp;
import org.snmp4j.TransportMapping;
import org.snmp4j.event.ResponseEvent;
import org.snmp4j.smi.Address;
import org.snmp4j.smi.GenericAddress;
import org.snmp4j.smi.OctetString;
import org.snmp4j.smi.UdpAddress;
import org.snmp4j.smi.VariableBinding;
import org.snmp4j.transport.DefaultUdpTransportMapping;
import com.prince.snmp.tool.Command;
import com.prince.snmp.tool.trap.dataGenerator.ITrapGenerator;
import com.prince.snmp.tool.util.Configure;

public class TrapSender implements Command{
	private Snmp snmp;
	private Address targetAddress;
	private ITrapGenerator generator;
	
	public TrapSender(ITrapGenerator generator) {
		this.generator = generator;
		targetAddress = GenericAddress.parse(Configure.getInstance().getUdpTrapIpPort());
		TransportMapping<UdpAddress> transport = null;
		try {
			transport = new DefaultUdpTransportMapping();
			snmp = new Snmp(transport);
			transport.listen();
		} catch (IOException e) {
			e.printStackTrace();
		}
	}
	
	public void sendTrap(){
		CommunityTarget target = new CommunityTarget();
		target.setAddress(targetAddress);
		target.setRetries(Configure.getInstance().getRetries());
		target.setTimeout(Configure.getInstance().getTimeOut());
		target.setCommunity(new OctetString(Configure.getInstance().getCommunity()));
		target.setVersion(Configure.getInstance().getSnmpVersion());
		
		List<TrapData> datas = generator.generateTrapData();
		
		try {
			for (TrapData trapData : datas) {
				sendPdu(trapData, target);
			}
		} catch (IllegalAccessException e) {
			e.printStackTrace();
		} catch (InvocationTargetException e) {
			e.printStackTrace();
		} catch (NoSuchMethodException e) {
			e.printStackTrace();
		} catch (IOException e) {
			e.printStackTrace();
		}
	}
	
	private void sendPdu(TrapData trapData, CommunityTarget target) throws IllegalAccessException, InvocationTargetException, NoSuchMethodException, IOException {
		PDU pdu = MoToPdu.moToPdu(trapData);
		ResponseEvent respEvnt = snmp.send(pdu, target);
		
		// 解析Response  
        if (respEvnt != null && respEvnt.getResponse() != null) {  
            Vector<VariableBinding> recVBs = (Vector<VariableBinding>) respEvnt.getResponse().getVariableBindings();  
            for (int i = 0; i < recVBs.size(); i++) {  
                VariableBinding recVB = recVBs.elementAt(i);  
                System.out.println(recVB.getOid() + " : " + recVB.getVariable());  
            }  
        }
	}

	
}
  •   trap主要注意必须设置两个VariableBingding

                pdu.add(new VariableBinding(SnmpConstants.sysUpTime, new TimeTicks(trap.getSysUpTime())));

 

                pdu.add(new VariableBinding(SnmpConstants.snmpTrapOID, new OID(trap.getTrapOid())))

 

4. get

     

	private static void simpleGet() throws IOException {
		TransportMapping<UdpAddress> transport = new DefaultUdpTransportMapping();
		Snmp snmp = new Snmp(transport);
		transport.listen();
		
		CommunityTarget target = new CommunityTarget(); 
		target.setCommunity(new OctetString("CONV"));
		Address targetAddress = GenericAddress.parse("udp:10.141.43.237/161"); 
		target.setAddress(targetAddress);
		target.setRetries(3);
		target.setTimeout(3000);
		target.setVersion(SnmpConstants.version2c);
		
		PDU pdu = new PDU();  
        pdu.add(new VariableBinding(new OID(".1.3.6.1.4.1.7569.1.2.1.23.3.1")));  
        pdu.setType(PDU.GETBULK);
        pdu.setMaxRepetitions(20);
        pdu.setNonRepeaters(0);
        
        ResponseEvent respEvnt = snmp.send(pdu, target);  
        if (respEvnt != null && respEvnt.getResponse() != null) {  
               Vector<VariableBinding> recVBs = (Vector<VariableBinding>) respEvnt.getResponse().getVariableBindings();  
               for (int i = 0; i < recVBs.size(); i++) {  
                      VariableBinding recVB = recVBs.elementAt(i);  
                      System.out.println(recVB.getOid() + " : " + recVB.getVariable());  

               }  

        }  
	}
  •      get相对于比较简单,资料也比较多。主要是设定pdu.setType(PDU.GETBULK);
  • 利用getnext和一些判断可以实现walk.
  • http://blog.sina.com.cn/s/blog_6cb15f8f0100yx4p.html 这个哥们儿写得非常好

具体的代码没有写,因为下一篇会共享一个小的工具,可以以配置文件为基础来构建Receiver,发送Trap,构建Agent等。

 

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