ajanta.server
Class AgentServer

java.lang.Object
  |
  +--java.rmi.server.RemoteObject
        |
        +--java.rmi.server.RemoteServer
              |
              +--java.rmi.server.UnicastRemoteObject
                    |
                    +--ajanta.server.AgentServer

All Implemented Interfaces:

AServer, java.rmi.Remote, Reportable, Resource, java.io.Serializable

public class AgentServer

extends java.rmi.server.UnicastRemoteObject

implements AServer, Resource, Reportable

Ajanta provides a generic agent server that can be suitably extended by a programmer to define an application-specific server. It supports several important functions:
1. Agent Transfer Protocol for agent migration to/from other servers.
2. Execution of visiting agents within secure protection domains.
3. Secure access to server resources for agents.
4. Primitives for inter-agent communication, resource access and migration.
5. Secure agent control and monitoring functions for agent creators.
The server's agent environment object acts as the interface between agents and the services provided at the host. Agents can invoke operations on their environment that allow them to migrate, communicate, access resources, etc. Each server maintains a domain registry that keeps track of the agents currently executing on it. A server usually provides access to some application-defined resources. Such resources are registered in the server's resource registry. This registry maps the URN of a resource to its object reference. A server has to explicitly make a resource visible to visiting agents by registering it in the resource registry by using the registerResource function.

See Also:

Serialized Form

Field Summary

protected ajanta.server.ATPListener	atp thread which handles agent transfer
protected int	atp_port port number on which agent transfer take place
protected ajanta.naming.CA	ca
protected java.net.URL	codeBase Code server running in this Agent Server
protected ajanta.server.ClassServer	cs class (code) server thread
protected int	cs_port port number of class (code) server thread
protected java.util.Hashtable	dd The domains database table -- conatin an entry for all the agent currently residing on the server
protected java.security.Signature	dsa DSA signature object
protected java.security.PrivateKey	dsa_priv DSA private key
protected java.security.PublicKey	dsa_pub DSA public key
protected java.security.Signature	dsa_v DSA object for signature verification
protected ajanta.crypto.ElGamal	eg ElGamal object used for encryption
protected ajanta.crypto.EGPrivateKey	eg_priv ElGamal private key for server's owner
protected ajanta.crypto.EGPublicKey	eg_pub ElGamal public key for server's owner
protected ajanta.server.AgentEnv	host server's context object -- an instance of this is passed to all the visting agents
protected java.io.PrintStream	logger a logger file output stream
protected java.security.cert.X509Certificate	myCertificate
protected java.lang.String	myHost DNS name of my host machine
protected ajanta.naming.URN	myURN this agent server's URN ( name )
protected ajanta.server.NRAccess	namereg a sycronized class for calling namereg api's
protected java.security.cert.X509Certificate	nameregistryCertificate
protected java.util.Hashtable	nameTGmap maps agent names to thread group id
protected java.net.URL	rmiRegURL local server specific rmi registry
protected java.util.Hashtable	rr The resource registry table -- contain an entry for each registered resource
protected ajanta.server.AjantaSecurityManager	securityManager the security manager for the server
protected java.security.SecureRandom	srand Secure random number generator
protected ajanta.util.AgentTicketing	tkt used for ticket generation/verification

Fields inherited from class java.rmi.server.RemoteObject

ref

Constructor Summary

AgentServer(java.lang.String n)
AgentServer constructor

Method Summary

ajanta.util.Ticket	authenticate(ajanta.naming.URN caller, int nonce, ajanta.util.ContextObject context) It is used to obtain ticket from this server from a remote site.
boolean	checkAdmissionPolicy(ajanta.agent.Credentials agentCredentials, java.net.InetAddress inetAddress, ajanta.naming.URN senderAgentServerURN) The function returns true if the incoming agent can be accepted based on the agent server admission policy.
byte[]	decrypt(ajanta.crypto.EGCipherText cipher)
void	deleteDDEntry(ajanta.server.DDEntry obj) This function removes the calling agent DDEntry from the domain database.
void	deleteDDEntry(ajanta.naming.URN name) This function removes the calling agent DDEntry from the domain database.
ajanta.crypto.EGCipherText	encrypt(ajanta.crypto.EGPublicKey pk, byte[] plaintext)
ajanta.server.AServer	getAgentCurrentServer(ajanta.naming.URN agentURN) given URN of agent it locates it's current server and return reference to the server.
ajanta.naming.CascadedCertificate	getCascadedCertificate(int key_length, long duration)
void	getCertificiates()
long	getMaxDuration(ajanta.naming.URN agentURN)
ajanta.server.NRAccess	getNR() It returns a reference to NRAcess - sycronized class for calling namereg api's
java.net.URL	getRegURL() Return local server specific rmi registry URL.
java.security.PrivateKey	getTemporaryPrivateKey()
java.security.PublicKey	getTemporaryPublicKey()
void	launch(ajanta.agent.Agent ag, ajanta.naming.URN dest, java.lang.String method, java.lang.Class[] formals, java.lang.Object[] actuals) It launches a given agent to the specified destination.
boolean	logEvent(ajanta.logger.Event e)
static void	main(java.lang.String[] args) Main program, which starts up the agent server This is only a generic main program.
java.lang.String	ping() Returns Agent Server Status.
void	recall(ajanta.naming.URN target, ajanta.naming.URN reportTo, ajanta.util.Ticket t) It is used to recall an agent ...which basically allow an agent to complete its task at the current server and upon completion migate it to the reportTo server ( but it aborts its prespecifed itinerary).
void	recall(ajanta.naming.URN target, ajanta.naming.URN recaller, ajanta.naming.URN reportTo) It is used to recall an agent ...which basically allow an agent to complete its task at the current server ( but it aborts its prespecifed itinerary) and upon completion migate it to the reportTo server.
void	registerAgent(ajanta.agent.Agent ag) Registers an agent with the name registry, If an older entry exists try to rebind the agent.
ajanta.util.Ticket	remoteServerTicket(ajanta.server.AServer targetServer, ajanta.naming.URN caller, int nonce, java.security.PrivateKey dsa_priv) It is used to do two way authentication...first it obtains a Ticket from the remote server and then using that ticket it creates another ticket and return to the caller.
void	report(ajanta.agent.Agent ag) This method is invoked by agents which report back to their home site, either because their task is done, or in response to reacll / retract, or because they have encountered some exception which they could not handle.
void	retract(ajanta.naming.URN target, ajanta.naming.URN reportTo, ajanta.util.Ticket t) It is used to retract an agent ...it preempts the agent from its current task and its prespecifed itinerary.
void	retract(ajanta.naming.URN target, ajanta.naming.URN retractor, ajanta.naming.URN reportTo) It is used to retract an agent ...it preempts the agent from its current task and its prespecified itinerary.
byte[]	sign(byte[] text)
void	terminate(ajanta.naming.URN target) It is used to abort an agent ...it immediately kill the agent.
void	terminate(ajanta.naming.URN target, ajanta.util.Ticket t) It is used to abort an agent ...it immediately kills the agent.
boolean	verify(byte[] text, byte[] sig, java.security.PublicKey pub)
ajanta.naming.URN	whoAreYou() A simple method in the AServer interface, for obtaining an agent server's URN

Methods inherited from class java.rmi.server.UnicastRemoteObject

clone, exportObject, exportObject, exportObject, unexportObject

Methods inherited from class java.rmi.server.RemoteServer

getClientHost, getLog, setLog

Methods inherited from class java.rmi.server.RemoteObject

equals, getRef, hashCode, toString, toStub

Methods inherited from class java.lang.Object

finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

myURN

protected ajanta.naming.URN myURN

this agent server's URN ( name )

myHost

protected java.lang.String myHost

DNS name of my host machine

codeBase

protected java.net.URL codeBase

Code server running in this Agent Server

rmiRegURL

protected java.net.URL rmiRegURL

local server specific rmi registry

dd

protected java.util.Hashtable dd

The domains database table -- conatin an entry for all the agent currently residing on the server

rr

protected java.util.Hashtable rr

The resource registry table -- contain an entry for each registered resource

nameTGmap

protected java.util.Hashtable nameTGmap

maps agent names to thread group id

atp

protected ajanta.server.ATPListener atp

thread which handles agent transfer

atp_port

protected int atp_port

port number on which agent transfer take place

cs

protected ajanta.server.ClassServer cs

class (code) server thread

cs_port

protected int cs_port

port number of class (code) server thread

host

protected ajanta.server.AgentEnv host

server's context object -- an instance of this is passed to all the visting agents

eg_pub

protected ajanta.crypto.EGPublicKey eg_pub

ElGamal public key for server's owner

eg_priv

protected ajanta.crypto.EGPrivateKey eg_priv

ElGamal private key for server's owner

dsa_pub

protected java.security.PublicKey dsa_pub

DSA public key

dsa_priv

protected java.security.PrivateKey dsa_priv

DSA private key

eg

protected ajanta.crypto.ElGamal eg

ElGamal object used for encryption

dsa

protected java.security.Signature dsa

DSA signature object

tkt

protected ajanta.util.AgentTicketing tkt

used for ticket generation/verification

srand

protected java.security.SecureRandom srand

Secure random number generator

dsa_v

protected java.security.Signature dsa_v

DSA object for signature verification

securityManager

protected ajanta.server.AjantaSecurityManager securityManager

the security manager for the server

namereg

protected ajanta.server.NRAccess namereg

a sycronized class for calling namereg api's

logger

protected java.io.PrintStream logger

a logger file output stream

ca

protected ajanta.naming.CA ca

myCertificate

protected java.security.cert.X509Certificate myCertificate

nameregistryCertificate

protected java.security.cert.X509Certificate nameregistryCertificate

Constructor Detail

AgentServer

public AgentServer(java.lang.String n)
            throws java.rmi.RemoteException

AgentServer constructor

Parameters:

n - urn ( name ) of the agent server

See Also:

AgentServer

Method Detail

decrypt

public byte[] decrypt(ajanta.crypto.EGCipherText cipher)

encrypt

public ajanta.crypto.EGCipherText encrypt(ajanta.crypto.EGPublicKey pk,
                                          byte[] plaintext)

sign

public byte[] sign(byte[] text)
            throws java.security.SignatureException

java.security.SignatureException

verify

public boolean verify(byte[] text,
                      byte[] sig,
                      java.security.PublicKey pub)
               throws java.security.InvalidKeyException,
                      java.security.SignatureException

java.security.InvalidKeyException

java.security.SignatureException

whoAreYou

public ajanta.naming.URN whoAreYou()
                            throws java.rmi.RemoteException

A simple method in the AServer interface, for obtaining an agent server's URN

Specified by:

whoAreYou in interface AServer

java.rmi.RemoteException

getAgentCurrentServer

public ajanta.server.AServer getAgentCurrentServer(ajanta.naming.URN agentURN)

given URN of agent it locates it's current server and return reference to the server. Useful in recall, retract and terminate calls

Parameters:

agentURN - URN of the agent to be located

Returns:

return reference to current server of the agent

See Also:

AServer

recall

public void recall(ajanta.naming.URN target,
                   ajanta.naming.URN recaller,
                   ajanta.naming.URN reportTo)
            throws java.rmi.RemoteException

It is used to recall an agent ...which basically allow an agent to complete its task at the current server ( but it aborts its prespecifed itinerary) and upon completion migate it to the reportTo server. This do not involve authentication and will be deprecated in future release.

Specified by:

recall in interface AServer

Parameters:

target - URN of the agent to be relocated

recaller - URN of the recaller

reportTo - URN of the entity to whom agent has to report

java.rmi.RemoteException

retract

public void retract(ajanta.naming.URN target,
                    ajanta.naming.URN retractor,
                    ajanta.naming.URN reportTo)
             throws java.rmi.RemoteException

It is used to retract an agent ...it preempts the agent from its current task and its prespecified itinerary. Then immediately migate it to the reportTo server. This do not involve authentication and will be deprecated in future release.

Specified by:

retract in interface AServer

Parameters:

target - URN of the agent to be relocated

reportTo - URN of the entity to whom agent has to report

java.rmi.RemoteException

terminate

public void terminate(ajanta.naming.URN target)
               throws java.rmi.RemoteException

It is used to abort an agent ...it immediately kill the agent. This do not involve authentication and will be deprecated in future release.

Specified by:

terminate in interface AServer

Parameters:

target - URN of the agent to be terminated

java.rmi.RemoteException

ping

public java.lang.String ping()
                      throws java.rmi.RemoteException

Returns Agent Server Status. Currently "alive".

Specified by:

ping in interface AServer

java.rmi.RemoteException

authenticate

public ajanta.util.Ticket authenticate(ajanta.naming.URN caller,
                                       int nonce,
                                       ajanta.util.ContextObject context)

It is used to obtain ticket from this server from a remote site.

Specified by:

authenticate in interface AServer

Parameters:

caller - caller identity( URN )

nonce - random number used as challenge

remoteServerTicket

public ajanta.util.Ticket remoteServerTicket(ajanta.server.AServer targetServer,
                                             ajanta.naming.URN caller,
                                             int nonce,
                                             java.security.PrivateKey dsa_priv)
                                      throws java.rmi.RemoteException

It is used to do two way authentication...first it obtains a Ticket from the remote server and then using that ticket it creates another ticket and return to the caller.

Parameters:

targetServer - reference to the remote agent server

caller - URN of the caller ( server )

nonce - any random number

dsa_priv - dsa private key of the caller

Returns:

Ticket from the remote server...used for future authentication

java.rmi.RemoteException

recall

public void recall(ajanta.naming.URN target,
                   ajanta.naming.URN reportTo,
                   ajanta.util.Ticket t)
            throws java.rmi.RemoteException,
                   java.security.InvalidKeyException,
                   java.security.SignatureException

It is used to recall an agent ...which basically allow an agent to complete its task at the current server and upon completion migate it to the reportTo server ( but it aborts its prespecifed itinerary). Recaller must authenticate himself with the remote server inorder to recall the agent.Only owner, creator or gurdian are allowed to recall an agent.

     AServer targetServer = getAgentCurrentServer( agentURN );
     Ticket ticket = remoteServerTicket ( targetServer, myURN , 3000, dsa_priv );
     recall (agentURN , myURN , ticket )
 

Specified by:

recall in interface AServer

Parameters:

target - URN of the agent to be relocated

reportTo - URN of the entity to whom agent has to report

t - ticket obtained from the remote server

java.rmi.RemoteException

java.security.InvalidKeyException

java.security.SignatureException

retract

public void retract(ajanta.naming.URN target,
                    ajanta.naming.URN reportTo,
                    ajanta.util.Ticket t)
             throws java.rmi.RemoteException,
                    java.security.InvalidKeyException,
                    java.security.SignatureException

It is used to retract an agent ...it preempts the agent from its current task and its prespecifed itinerary. Then migate the agent to the reportTo server. Retractor must authenticate himself with the remote server inorder to retract the agent.Only owner, creator or gurdian are allowed to retract an agent.

     AServer targetServer = getAgentCurrentServer( agentURN );
     Ticket ticket = remoteServerTicket ( targetServer, myURN , 3000, dsa_priv );
     retract (agentURN , myURN , ticket )
 

Specified by:

retract in interface AServer

Parameters:

target - URN of the agent to be retracted

reportTo - URN of the entity to whom agent has to report

t - ticket obtained from the remote server

java.rmi.RemoteException

java.security.InvalidKeyException

java.security.SignatureException

terminate

public void terminate(ajanta.naming.URN target,
                      ajanta.util.Ticket t)
               throws java.rmi.RemoteException,
                      java.security.InvalidKeyException,
                      java.security.SignatureException

It is used to abort an agent ...it immediately kills the agent. Caller must authenticate himself with the remote server inorder to terminate the agent.Only owner, creator or gurdian are allowed to terminate an agent.

     AServer targetServer = getAgentCurrentServer( agentURN );
     Ticket ticket = remoteServerTicket ( targetServer, myURN , 3000, dsa_priv );
     terminate (agentURN  , ticket )
 

Specified by:

terminate in interface AServer

Parameters:

target - URN of the agent to be terminated

java.rmi.RemoteException

java.security.InvalidKeyException

java.security.SignatureException

launch

public void launch(ajanta.agent.Agent ag,
                   ajanta.naming.URN dest,
                   java.lang.String method,
                   java.lang.Class[] formals,
                   java.lang.Object[] actuals)
            throws LaunchFailedException

It launches a given agent to the specified destination.

Parameters:

ag - reference of the agent to be launched

dest - URN of the destination

method - name of the method to execute

formals - array of class names of method parametrs

actuals - array of objects i.e. values of the parametrs to the method

LaunchFailedException

report

public void report(ajanta.agent.Agent ag)
            throws AgentTerminateException

This method is invoked by agents which report back to their home site, either because their task is done, or in response to reacll / retract, or because they have encountered some exception which they could not handle. By default it just print a message identifying the which agent is reporting. An application' agent server shoul overide this method to provide application specific handeling.

Specified by:

report in interface Reportable

Parameters:

ag - reference of the agent reporting

AgentTerminateException

getNR

public ajanta.server.NRAccess getNR()

It returns a reference to NRAcess - sycronized class for calling namereg api's

deleteDDEntry

public void deleteDDEntry(ajanta.server.DDEntry obj)

This function removes the calling agent DDEntry from the domain database.

Parameters:

obj - reference of the DDEntry to be deleted

deleteDDEntry

public void deleteDDEntry(ajanta.naming.URN name)

This function removes the calling agent DDEntry from the domain database.

getRegURL

public java.net.URL getRegURL()

Return local server specific rmi registry URL.

registerAgent

public void registerAgent(ajanta.agent.Agent ag)

Registers an agent with the name registry, If an older entry exists try to rebind the agent.

Parameters:

ag - reference of the agent to be registered

main

public static void main(java.lang.String[] args)

Main program, which starts up the agent server This is only a generic main program. Application developers should create subclasses of AgentServer and implement their own main() methods. The only requirement is that the main program should instantiate their agent server class, and use it to launch agents into the network.

checkAdmissionPolicy

public boolean checkAdmissionPolicy(ajanta.agent.Credentials agentCredentials,
                                    java.net.InetAddress inetAddress,
                                    ajanta.naming.URN senderAgentServerURN)

The function returns true if the incoming agent can be accepted based on the agent server admission policy. The users should override this method, in their classes which inherit from AgentServer. The default implementation always returns true, which means an agent server accepts all agents.

logEvent

public boolean logEvent(ajanta.logger.Event e)

getCertificiates

public void getCertificiates()

getCascadedCertificate

public ajanta.naming.CascadedCertificate getCascadedCertificate(int key_length,
                                                                long duration)

getTemporaryPrivateKey

public java.security.PrivateKey getTemporaryPrivateKey()

getTemporaryPublicKey

public java.security.PublicKey getTemporaryPublicKey()

getMaxDuration

public long getMaxDuration(ajanta.naming.URN agentURN)