package jcifs.smb;

import java.security.Key;
import java.util.Iterator;

import javax.security.auth.Subject;
import javax.security.auth.kerberos.KerberosTicket;

import org.ietf.jgss.GSSContext;
import org.ietf.jgss.GSSCredential;
import org.ietf.jgss.GSSException;
import org.ietf.jgss.GSSManager;
import org.ietf.jgss.GSSName;
import org.ietf.jgss.Oid;

// >>SmbAuthenticator
/**
 * This class used to provide Kerberos feature when setup GSSContext.
 * 
 * @author Shun
 */
class Kerb5Context {
    private static final String OID = "1.2.840.113554.1.2.2";
    private GSSContext gssContext;
    
    Kerb5Context(
            String host, 
            String service, 
            String name,
            int userLifetime,
            int contextLifetime
            ) throws GSSException{
        GSSManager manager = GSSManager.getInstance();
        Oid oid = null; 
        GSSName serviceName = null;
        GSSName clientName = null;
        GSSCredential clientCreds = null;
        
        oid = new Oid(OID);

        serviceName = manager.createName(
                service + "@" + host, GSSName.NT_HOSTBASED_SERVICE, oid);
        if(name!=null){
            clientName = manager.createName(name, GSSName.NT_USER_NAME, oid);
            clientCreds = manager.createCredential(
                        clientName, userLifetime, oid, GSSCredential.INITIATE_ONLY);
        }
        gssContext = manager.createContext(
                serviceName,
                oid,
                clientCreds,
                contextLifetime);
    }
    
    GSSContext getGSSContext(){
        return gssContext;
    }
    
    Key searchSessionKey(Subject subject) throws GSSException{
        MIEName src = new MIEName(gssContext.getSrcName().export());
        MIEName targ = new MIEName(gssContext.getTargName().export());
        Iterator iter = subject.getPrivateCredentials(KerberosTicket.class).iterator();
        while (iter.hasNext()) {
            KerberosTicket ticket = (KerberosTicket) iter.next();
            MIEName client = new MIEName(gssContext.getMech(), ticket.getClient().getName());
            MIEName server = new MIEName(gssContext.getMech(), ticket.getServer().getName());
            if(src.equals(client)&&targ.equals(server)){
                return ticket.getSessionKey();
            }
        }
        return null;
    }
    public void dispose() throws GSSException {
        if(gssContext != null){
            gssContext.dispose();
        }
    }
}
// SmbAuthenticator<<