SecurityMonitor.java

package at.ac.ait.archistar.backendserver;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import at.archistar.bft.messages.AbstractCommand;
import at.archistar.bft.messages.CheckpointMessage;

/**
 * This class responds to the different error situations
 *
 * TODO: maybe use singleton pattern for this?
 *
 * @author andy
 */
public class SecurityMonitor {

    private final Logger logger = LoggerFactory.getLogger(SecurityMonitor.class);

    private final OzymandiasServer myself;

    public SecurityMonitor(OzymandiasServer myself) {
        this.myself = myself;
    }

    /**
     * TODO: this should be called if the sequence nrs start to differ
     *
     * what to do: executed operations should be the same at 2f+1 replicas. As
     * they are the same everywhere we should be able to perform the missing
     * operations and continue
     *
     * everything before "2f+1 prepared operations" should be able to be redone
     * by resetting the transactions/operations state to INCOMING and forcing
     * the new primary to resend the PREPREPARE message with n =
     * max(sequence)+1. This will lead to holes in our sequence numbers -- but
     * then, this should not be a problem.
     *
     * @return
     */
    public boolean replicasMightBeMalicous() {
        logger.warn("primary might be malicous?");

        myself.tryAdvanceEra();
        assert (false);
        return true;
    }

    public void unreachableCodePath() {
        assert (false);
    }

    public void localMalicousErrorDetected() {
        assert (false);
    }

    /**
     * TODO: this should be called if my execution log seems to be running
     * behind the other replicas
     *
     * @return
     */
    public void myselfNeedsReplay() {
        assert (false);
    }

    /**
     * a checkpoint message was not consistent with already received checkpoint
     * messages
     *
     * @param msg
     */
    public void invalidCheckpointMessage(CheckpointMessage msg) {
        /* wrong message data type */
        logger.error("invalid checkpoint message server " + myself.getReplicaId() + " message:" + msg);
        assert (false);
    }

    public void invalidMessageReceived(AbstractCommand msg) {
        logger.error("invalid message received on " + myself.getReplicaId() + " message:" + msg);
        assert (false);
    }
}