org.opennms.netmgt.dhcpd

Class Dhcpd

java.lang.Object

org.opennms.netmgt.daemon.AbstractServiceDaemon

org.opennms.netmgt.dhcpd.Dhcpd

All Implemented Interfaces:

Runnable, Observer, Fiber, PausableFiber, SpringServiceDaemon, ServiceDaemon, org.springframework.beans.factory.DisposableBean, org.springframework.beans.factory.InitializingBean

public final class Dhcpd
extends AbstractServiceDaemon
implements Runnable, Observer

The DHCP client daemon serves as a multiplexor for DHCP requests and responses. The Bootp/DHCP protocol specifies that a DHCP server listens for requests on local UDP/67 and will either send/broadcast responses to UDP/68 or UDP/67 or will unicast responses back to the client's UDP port on from which the request originated.

The DHCP daemon accepts client connections on TCP/5818. Once a client is connected it can begin forwarding requests. A list of all currently connected clients is maintained. Requests have the following format:

• byte 1 - byte 4 : 32-bit remote host IP address
• byte 5 - byte 8 : 32-bit buffer length
• byte 9 - byte n : buffer containing the formatted DHCP discover request.

The client indicates that it is finished by sending a request with the remote host IP address set to zero (0).

Incoming requests are sent to UDP/67 on specified remote host. If the remote host is runnning a DHCP server it will send/broadcast an appropriate response to UDP/68 or UDP/67 (or will unicast the response).

The DHCP daemon includes a listener thread which binds to UDP/68 or UDP/67 and simply listens for any incoming DHCP responses. In extended mode, threads are started on both ports. When a datagram is received by the listener thread(s) it loops through the list of currently connected clients and forwards the DHCP response packet to each client. It is the responsibility of the client to validate that the datagram is in response to a DHCP request packet that it generated.

Author:

Mike , OpenNMS

Field Summary

Fields inherited from interface org.opennms.core.fiber.PausableFiber

PAUSE_PENDING, PAUSED, RESUME_PENDING

Fields inherited from interface org.opennms.core.fiber.Fiber

RUNNING, START_PENDING, STARTING, STATUS_NAMES, STOP_PENDING, STOPPED

Method Summary

Methods

Modifier and Type	Method and Description
static Dhcpd	getInstance() Returns the singular instance of the DHCP server.
static long	isServer(InetAddress address) Contacts the public server and checks to see if the the passed address is a DHCP server.
static long	isServer(InetAddress address, long timeout, int retries) Contacts the public server and checks to see if the the passed address is a DHCP server.
protected void	onInit() onInit
protected void	onStart() onStart
protected void	onStop() onStop
void	run() The main routine of the DHCP server.
void	update(Observable inst, Object ignored) This method is called by the observable instances that the server has registered to receive.

Methods inherited from class org.opennms.netmgt.daemon.AbstractServiceDaemon

afterPropertiesSet, destroy, getName, getStatus, getStatusText, init, isPaused, isRunning, isStarting, onPause, onResume, pause, resume, setStatus, start, status, stop, waitForStatus, waitForStatus

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

onStart

protected void onStart()

onStart

Overrides:

onStart in class AbstractServiceDaemon

onStop

protected void onStop()

onStop

Overrides:

onStop in class AbstractServiceDaemon

run

public void run()

The main routine of the DHCP server. This method accepts incoming client requests and starts new client handlers to process each request.

Specified by:

run in interface Runnable

update

public void update(Observable inst,
          Object ignored)

This method is called by the observable instances that the server has registered to receive.

Specified by:

update in interface Observer

getInstance

public static Dhcpd getInstance()

Returns the singular instance of the DHCP server.

Returns:

a Dhcpd object.

isServer

public static long isServer(InetAddress address,
            long timeout,
            int retries)
                     throws IOException

Contacts the public server and checks to see if the the passed address is a DHCP server.

Parameters:

address - The address to query.

timeout - The time to wait between retries.

retries - The maximum number of attempts.

Returns:

response time in milliseconds if remote box is a DHCP server or -1 if it is NOT.

Throws:

IOException - Thrown if an error occurs.

isServer

public static long isServer(InetAddress address)
                     throws IOException

Contacts the public server and checks to see if the the passed address is a DHCP server.

Parameters:

address - The address to query.

Returns:

response time in milliseconds if remote box is a DHCP server or -1 if it is NOT.

Throws:

IOException - Thrown if an error occurs.

onInit

protected void onInit()

onInit

Specified by:

onInit in class AbstractServiceDaemon