用snmp4j开发网管应用(二) -- 使用snmp4j

小灰灰 2022-03-11 14:47 218阅读 0赞

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，

或者是这个链接下载http://download.csdn.net/detail/three\_man/7478029

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。

这个文档的下载链接：http://download.csdn.net/detail/three\_man/7477953

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，可以在这里下载：http://download.csdn.net/detail/three\_man/7477991

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。这个也提供个下载地址吧： http://download.csdn.net/detail/three\_man/7478061

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。

[SNMP4J-Agent-2.2-Instrumentation-Guide.pdf]: http://www.snmp4j.org/SNMP4J-Agent-Instrumentation-Guide-2.2.pdf