simplesnmp.java

监控大型网络的软件。能够自动发现拓扑结构

			boolean timedOut = false;
			try {
				if (getNext) {
					if (getAll) {
						// Do our own subtree walk routine, to avoid a known bug in drexel snmp
						var = new SNMPVarBindList();
						String nextoid = baseOid;
						while (true) {
							SNMPVarBindList nextpair = comInterface.getNextMIBEntry(nextoid);
							SNMPObject snmpobj = nextpair.getSNMPObjectAt(0);
							if (snmpobj instanceof SNMPNull) break;
							SNMPSequence pair = (SNMPSequence)snmpobj;
							SNMPObjectIdentifier snmpOID = (SNMPObjectIdentifier)pair.getSNMPObjectAt(0);
							nextoid = snmpOID.toString();
							if (!nextoid.startsWith(baseOid) || nextoid.equals(baseOid)) break;
							
							var.addSNMPObject(pair);
						}
					} else {
						var = new SNMPVarBindList();
						String nextoid = baseOid;
						for (int i=0; i < getCnt; i++) {
							SNMPVarBindList nextpair = comInterface.getNextMIBEntry(nextoid);
							SNMPObject snmpobj = nextpair.getSNMPObjectAt(0);
							if (snmpobj instanceof SNMPNull) break;
							SNMPSequence pair = (SNMPSequence)snmpobj;
							SNMPObjectIdentifier snmpOID = (SNMPObjectIdentifier)pair.getSNMPObjectAt(0);
							nextoid = snmpOID.toString();

							var.addSNMPObject(pair);
						}
					}
				} else {
					var = comInterface.getMIBEntry(baseOid);
				}
			} catch (SocketTimeoutException exp) {
				timedOut = true;
			} catch (SNMPBadValueException exp) {
				System.err.println("SNMPBadValueException: " + exp);
				return l;
			} catch (SNMPException exp) {
				if (!(exp instanceof SNMPGetException && exp.getMessage() != null && exp.getMessage().indexOf("not available for retrieval") >= 0)) {
					System.err.println("SNMPException: " + exp);
				}
				return l;
			}

			if (timedOut) {
				timeoutCnt++;
				if (timeoutCnt >= retries) {
					throw new TimeoutException("Timed out " + timeoutCnt + " times, giving up");
				} else {
					// Re-try operation, but back off on the timeout value
					return getAllJavaSnmp(baseOid, getCnt, decodeHex, getNext, stripPrefix, stripCnt, timeout*backoff);
				}
			}
			timeoutCnt = 0;

			for (int i=0; i < var.size(); i++) {
				SNMPSequence pair = (SNMPSequence)(var.getSNMPObjectAt(i));
				SNMPObjectIdentifier snmpOID = (SNMPObjectIdentifier)pair.getSNMPObjectAt(0);
				SNMPObject snmpValue = pair.getSNMPObjectAt(1);

				String oid = snmpOID.toString();
				String data;
				if (!decodeHex && snmpValue instanceof SNMPOctetString) {
					data = toHexString((byte[])snmpValue.getValue());					
				} else {
					data = snmpValue.toString();
				}
				data = data.trim();
				if (data.length() == 0 && !(snmpValue instanceof SNMPOctetString)) {
					// Skip empty variables which are not strings
					continue;
				}
				String strippedOid = stripPrefix && oid.startsWith(baseOid) ? oid.substring(baseOid.length()) : oid;
				String[] s = {
					strippedOid.length() > 0 && strippedOid.charAt(0) == '.' ? strippedOid.substring(1) : strippedOid,
					data
				};
				s[0] = strip(s[0], '.', stripCnt, true);
				l.add(s);				
			}

		} catch (IOException e) {
			outl("  *ERROR*: Host: " + host + " IOException: " + e.getMessage() );
			e.printStackTrace(System.err);
		}
		getCnt = 0;
		return l;
	}

	private String toHexString(byte[] bytes) {
		StringBuffer sb = new StringBuffer();
		int[] ints = new int[bytes.length];
		for (int i=0; i < ints.length; i++) ints[i] = bytes[i] < 0 ? 256 + bytes[i] : bytes[i];
		for (int i=0; i < ints.length; i++) sb.append((i>0?":":"")+(ints[i]<16?"0":"")+Integer.toString(ints[i], 16));
		return sb.toString();
	}

	private ArrayList getAllWesthawk(String baseOid, int getCnt, boolean decodeHex, boolean getNext, int stripCnt) throws TimeoutException {
		ArrayList l = new ArrayList();

		/*
		try {
			checkSnmpContext();

			BlockPdu pdu = new BlockPdu(context);

			pdu.addOid(baseOid);
			pdu.setPduType(getNext ? BlockPdu.GETNEXT : BlockPdu.GET);

			boolean sentGetNext = getNext;
			String oid = baseOid;

			// Should we get the entire subtree?
			boolean getAll = getCnt == 0;

			while (true) {
				try {
					varbind vb;
					while ( (vb=pdu.getResponseVariableBinding()) != null) {
						oid = vb.getOid().getValue();
						if (!baseOid.equals(oid) && !oid.startsWith(baseOid+".")) break;

						// Reset timeoutCnt
						timeoutCnt = 0;

						// Behandle svaret vi har fått
						String data;
						{
							AsnObject o = vb.getValue();
							if (o instanceof AsnOctets) {
								AsnOctets ao = (AsnOctets)o;
								data = (decodeHex ? ao.toDisplayString() : ao.toHex());

								//outl("OID: " + oid + " S: " + data + " HEX: " + ao.toHex() );
							} else {
								 data = o.toString();
							}
							data = data.trim();
						}
						//outl("Base: " + baseOid);
						//outl("Oid : " + oid);

						// If the returned OID is of greater length than the baseOid, remove the baseOid prefix;
						// otherwise, use the empty string
						String[] s = {
							oid.length() == baseOid.length() ? "" : oid.substring(baseOid.length()+1, oid.length()),
							data.trim()
						};
						s[0] = strip(s[0], '.', stripCnt, true);
						l.add(s);

						if (!getAll && --getCnt == 0) break;

						pdu = new BlockPdu(context);
						pdu.setPduType(BlockPdu.GETNEXT);
						pdu.addOid(oid);
						if (getNextDelay > 0) {
							try {
								//System.err.println("Sleeping " + getNextDelay + " ms.");
								Thread.currentThread().sleep(getNextDelay);
							} catch (InterruptedException e) {
							}
						}
					}

				} catch (PduException e) {
					String m = e.getMessage();
					if (m.equals("No such name error")) {
						if (!sentGetNext) {
							pdu = new BlockPdu(context);
							pdu.setPduType(BlockPdu.GETNEXT);
							pdu.addOid(oid);
							sentGetNext = true;
							continue;
						}
					}
					else if (m.equals("Timed out")) {
						gotTimeout = true;
						timeoutCnt++;
						if (timeoutCnt >= timeoutLimit) {
							throw new TimeoutException("Too many timeouts, giving up");
						} else {
							// Re-try operation
							continue;
						}
					} else {
						outl("  *ERROR*: Host: " + host + " PduExecption: " + e.getMessage() );
					}
				}

				// Ferdig å hente meldinger
				break;

			} // while
		} catch (IOException e) {
			outl("  *ERROR*: Host: " + host + " IOException: " + e.getMessage() );
		}
		*/
		getCnt = 0;
		return l;
	}

	/**
	 * Check if the SnmpContext is still valid and update it if necessary.
	 *
	 * @return true if the SnmpContext was updated
	 */
	protected boolean checkSnmpContext() throws IOException {
		if (comInterface == null || !valid) {
			if (comInterface != null) comInterface.closeConnection();
			InetAddress hostAddress = InetAddress.getByName(host);
			comInterface = new SNMPv1CommunicationInterface(snmpVersion, hostAddress, cs_ro);
			if (this.socketTimeout > 0) comInterface.setSocketTimeout(this.socketTimeout);
			timeoutCnt = 0;
			valid = true;
			return true;
		}
		return false;
	}

	/**
	 * Check if the SnmpContext is still valid and update it if necessary.
	 *
	 * @return true if the SnmpContext was updated
	 */
	/*
	protected boolean checkSnmpContext2() throws IOException {
		if (context == null || !context.getHost().equals(host)) {
			if (context != null) context.destroy();
			//Exception e = new Exception("["+super.toString()+"] ["+Integer.toHexString(Thread.currentThread().hashCode())+"]");
			//e.printStackTrace(System.err);
			context = new SnmpContext(host, 161);
			//System.err.println("+++Creating context: " + context);
			context.setCommunity(cs_ro);
			timeoutCnt = 0;
			return true;
		} else if (!context.getCommunity().equals(cs_ro)) {
			context.setCommunity(cs_ro);
		}
		return false;
	}
	*/

	/**
	 * Deallocate any resources used.
	 */
	public void destroy() {
		if (comInterface != null) {
			try {
				comInterface.closeConnection();
			} catch (SocketException exp) {
			}
			comInterface = null;
		}
	}

	/**
	 * Deallocate any resources used.
	 */
	/*
	public void destroy2() {
		//Exception e = new Exception("["+super.toString()+"] ["+Integer.toHexString(Thread.currentThread().hashCode())+"]: " + context);
		//e.printStackTrace(System.err);
		if (context != null) {
			//System.err.println("---Destroying context: " + context);
			context.destroy();
			context = null;
		}
	}
	*/

	/**
	 * Check which version of SNMP the active device supports and set it active.
	 */
	public int checkSnmpVersion() {
		// First we check if the device can support SNMPv2
		onlyAskModule("0");
		setSnmpVersion(2);
		int snmpVersion = 1;
		try {
			getNext("1", 1, false, true);
			snmpVersion = 2;
		} catch (Exception e) {
			setSnmpVersion(1);
		} finally {
			onlyAskModule(null);
		}
		return snmpVersion;
	}

	public void finalize() {
		destroy();
	}

	private static void out(String s) { System.out.print(s); }
	private static void outl(String s) { System.out.println(s); }

	private static void err(String s) { System.err.print(s); }
	private static void errl(String s) { System.err.println(s); }

	/**
	 * @return The backoff factor
	 * @see #setBackoff(int)
	 */
	public int getBackoff() {
		return backoff;
	}

	/**
	 * Sets the backoff factor for retries.
	 * 
	 * <p>Whenever a request times out, the timeout limit 
	 * of each retry attempt will be multiplied by this factor.
	 * If set to 1, no timeout backoff will occur.</p>
	 * 
	 *  <p>The default factor is 2.</p>
	 * 
	 * @param backoff An integer backoff factor.
	 */
	public void setBackoff(int backoff) {
		this.backoff = backoff;
	}
}