---

RIPTable.java

Go to the documentation of this file.

/* Cyclops
 * FER - SPVP
 * Fakultet elektrotehnike i racunarstva (http://www.fer.hr/)
 * Unska 3, 10000 Zagreb, Hrvatska
 * (c) 2001 FER, Zagreb.
 */


package hr.fer.zesoi.cyclops;

import java.util.*;


public class RIPTable
{

    Vector table = new Vector();

    Node owner_node;

    public RIPTable (Node owner)
    {
        this.owner_node = owner;
    }
    /* RIPTable */

    public void addElement (Node destination, Node next_node, float cost)
    {
        RIPTableElement new_element = new RIPTableElement(destination, next_node, cost);
        table.addElement(new_element);
    }
    /* addElement */

    public Node findNextNodeForRouteTo (Node destination_node)
    {
        int i;
        RIPTableElement element;
        Node next_node;

        next_node = null;
        for (i=0; i<table.size(); i++)
            {
                element = (RIPTableElement)table.elementAt(i);
                /* Route is valid only if cost is less than infinity (16). */
                if (destination_node == element.destination_node)
                    {
                        next_node = element.next_node;
                        if (element.cost < 16)
                            {
                                return next_node;
                            }
                    }
                /* if */
            }
        /* for */
        return next_node;
    }
    /* findNextNodeForRouteTo */

    public void updateTable (Node node)
    {
        int i;
        int j;
        RIPTable another_table = node.getRIPTable();
        RIPTableElement old_element;
        RIPTableElement new_element;

        /* Metric update for node. */
        j = findEntry(node);
        if (j >= 0)
            {
                old_element = (RIPTableElement)table.elementAt(j);
                old_element.cost = 1;
                old_element.next_node = node;
                old_element.route_change_flag = true;
                old_element.route_timeout = 5;
                old_element.garbage_timeout = 5;
            }
        /* Metric update. */
        for (i=0; i<another_table.size(); i++)
            {
                new_element = another_table.elementAt(i);
                j = findEntry(new_element.destination_node);
                if ((j >= 0) &&
                    (new_element.destination_node != owner_node)
                    )
                    {
                        old_element = (RIPTableElement)table.elementAt(j);
                        if (new_element.next_node == owner_node)
                            {
                                /* Split horizon with poisoned reverse. Cost is 16. */
                                if (old_element.cost >= 16)
                                    {
                                        /* Better route exists. */
                                        old_element.cost = 16;
                                        old_element.next_node = node;
                                        old_element.route_change_flag = true;
                                        old_element.route_timeout = 5;
                                        old_element.garbage_timeout = 5;
                                    }
                                else if (old_element.next_node == node)
                                    {
                                        /* Update is required. */
                                        old_element.cost = 16;
                                        old_element.route_change_flag = true;
                                        old_element.route_timeout = 5;
                                        old_element.garbage_timeout = 5;
                                    }
                                else
                                    {
                                        old_element.route_change_flag = false;
                                    }

                            }
                        else
                            {
                                /* Normal update. */
                                if (old_element.cost >= new_element.cost + 1)
                                    {
                                        /* Better route exists. */
                                        old_element.cost = new_element.cost + 1;
                                        old_element.next_node = node;
                                        old_element.route_change_flag = true;
                                        old_element.route_timeout = 5;
                                        old_element.garbage_timeout = 5;
                                    }
                                else if (old_element.next_node == node)
                                    {
                                        /* Update is required. */
                                        old_element.cost = new_element.cost + 1;
                                        old_element.route_change_flag = true;
                                        old_element.route_timeout = 5;
                                        old_element.garbage_timeout = 5;
                                    }
                                else
                                    {
                                        old_element.route_change_flag = false;
                                    }
                            }
                        /* else */
                    }
                else if(new_element.destination_node != owner_node)
                    {
                        /* Create new table element. */
                        addElement(new_element.destination_node, node,
                                   new_element.cost + 1
                                   );
                    }
                /* else */
            }
        /* for */ /* Process all elements. */
    }
    /* updateTable */

    public void updateTable (RIPTable another_table)
    {
        int i;
        int j;
        RIPTableElement old_element;
        RIPTableElement new_element;

        for (i=0; i<another_table.size(); i++)
            {
                new_element = another_table.elementAt(i);
                j = findEntry(new_element.destination_node);
                if (j != -1)
                    {
                        old_element = (RIPTableElement)table.elementAt(j);
                        if (old_element.cost > new_element.cost + 1)
                            {
                                /* Better route exists. */
                                old_element.cost = new_element.cost + 1;
                                old_element.next_node = new_element.next_node;
                                old_element.route_change_flag = true;
                                old_element.route_timeout = 5;
                                old_element.garbage_timeout = 5;
                            }
                        else if (old_element.next_node == new_element.next_node)
                            {
                                /* Update if required. */
                                old_element.cost = new_element.cost + 1;
                                old_element.route_change_flag = true;
                                old_element.route_timeout = 5;
                                old_element.garbage_timeout = 5;
                            }
                        else
                            {
                                old_element.route_change_flag = false;
                            }
                    }
            
                else
                    {
                        /* Create new table element. */
                        addElement(new_element.destination_node, new_element.next_node,
                                   new_element.cost + 1
                                   );
                    }
                /* else */
            }
        /* for */ /* Process all elements. */
    }
    /* updateTable */

    public void garbageCollect ()
    {
        int i;
        RIPTableElement element;

        for (i=0; i<table.size(); i++)
            {
                element = (RIPTableElement)table.elementAt(i);
                if (!element.route_change_flag)
                    {
                        if (element.route_timeout>0)
                            {
                                element.route_timeout -= 1;
                            }
                        else if (element.garbage_timeout>0)
                            {
                                element.cost = 16;
                                element.garbage_timeout -= 1;
                            }
                        else
                            {
                                /* Entry expired, will be terminated. */
                                table.removeElementAt(i);
                                i--;
                            }
                    }
                /* if */
            }
        /* for */
    }
    /* garbageCollect */

    public void setCostToInfinity (Node node)
    {
        int i;
        RIPTableElement element;

        for (i=0; i<table.size(); i++)
            {
                element = (RIPTableElement)table.elementAt(i);
                if ((element.next_node == node) ||
                    (element.destination_node == node)
                    )
                    {
                        element.cost = 16;
                        element.route_change_flag = true;
                        element.route_timeout = 5;
                        element.garbage_timeout = 5;
                    }
                /* if */
            }
        /* for */
    }
    /* setCostToInfinity */

    public void setCost (Node destination, float cost)
    {
        int i;
        RIPTableElement element;

        for (i=0; i<table.size(); i++)
            {
                element = (RIPTableElement)table.elementAt(i);
                if (element.destination_node == destination)
                    {
                        element.cost = cost;
                        element.route_change_flag = true;
                        element.route_timeout = 5;
                        element.garbage_timeout = 5;
                    }
                /* if */
            }
        /* for */
    }
    /* setCost */

    public RIPTableElement elementAt (int index)
    {
        return (RIPTableElement)table.elementAt(index);
    }
    /* elementAt */

    public int findEntry (Node destination_node)
    {
        int i;
        RIPTableElement element;

        for (i=0; i<table.size(); i++)
            {
                element = (RIPTableElement)table.elementAt(i);
                if (element.destination_node == destination_node)
                    {
                        return i;
                    }
            }
        return -1;
    }
    /* findEntry */

    public int size ()
    {
        return table.size();
    }
    /* size */

}
/* RIPTable */

---