ospf_routing_table.c

vxworks下ospf协议栈

    if (I_am_an_area_border_router == TRUE)
        {
        for (sptr_area = ospf.sptr_area_list; sptr_area != NULL; sptr_area = sptr_next_area)
            {
            sptr_next_area = sptr_area->sptr_forward_link;
            if (sptr_area->flags._bit.nssa == TRUE)
                if ( ospf.router_id >= sptr_area->nssa_abr_to_convert_type_7_to_type_5)
                    ospf_translate_type_7_routes_into_type_5_lsa ();
            }

        }
#endif /*__NSSA__*/


    ospf_display_routing_table ();

    ospf_generate_events_due_to_routing_table_changes (sptr_old_routing_table_head);                    /* section 16.7 (page 163-164) */

    /* SPR#76812 -- Begin */
	for(table_type = OSPF_ROUTE_TABLE_NETWORK; table_type < OSPF_ROUTE_TABLE_MAX; table_type++)
	{
		for(index = 0x00000000L; index < OSPF_RT_HASH_TABLE_SIZE; index++)
		{
			if(sptr_old_routing_table_head[table_type][index] != NULL)
			{
		    	ospf_free_routing_table_nodes (sptr_old_routing_table_head[table_type][index]);
		    	ospf.sptr_old_routing_table[table_type][index] = NULL;
			}
		}
	}
    /* SPR#76812 -- End */


    for (sptr_area = ospf.sptr_area_list; sptr_area != NULL; sptr_area = sptr_next_area)
        {
        sptr_next_area = sptr_area->sptr_forward_link;
        if (sptr_area->bring_up_virtual_links == TRUE  )
            {
            ospf_bring_up_virtual_links_if_necessary (sptr_area);

            sptr_area->bring_up_virtual_links = FALSE;
            }
        }

    OSPF_PRINTF_ROUTING_TABLE (OSPF_ROUTING_TABLE_PRINTF, "OSPF: ----->>>>> Completed building the Routing Table And generated Appropriate events ---------------------\r\n");

#if defined __OSPF_DEBUG__
    ospf_print_areas_and_lsas ();
#endif


    return;
    }
/**********************************************************************************************************************************/
static OSPF_TRANSIT_AREA_ENTRY *ospf_create_transit_area_list (void)
    {
    OSPF_TRANSIT_AREA_ENTRY *sptr_transit_list;
    OSPF_AREA_ENTRY *sptr_area = NULL;
    OSPF_AREA_ENTRY *sptr_next_area = NULL;
    OSPF_TRANSIT_AREA_ENTRY *sptr_transit_entry;

    OSPF_PRINTF_DEBUG (OSPF_DEBUG_PRINTF, "OSPF: Entering ospf_create_transit_area_list\r\n");

    sptr_transit_list = NULL;

    for (sptr_area = ospf.sptr_area_list; sptr_area != NULL; sptr_area = sptr_next_area)
        {
        sptr_next_area = sptr_area->sptr_forward_link;
        if (sptr_area->flags._bit.transit == TRUE)
            {
            sptr_transit_entry = (OSPF_TRANSIT_AREA_ENTRY *) table_malloc (1, sizeof (OSPF_TRANSIT_AREA_ENTRY));

            if (sptr_transit_entry == NULL)
                {
                ospf_print_memory_error_message_and_free_buffer_if_necessary ((void *) NULL, "OSPF_TRANSIT_AREA_ENTRY");

                continue;
                }

            memset (sptr_transit_entry, 0x00, sizeof (OSPF_TRANSIT_AREA_ENTRY));

            sptr_transit_entry->sptr_forward_link = NULL;
            sptr_transit_entry->sptr_backward_link = NULL;
            sptr_transit_entry->sptr_area = sptr_area;

            if (sptr_transit_list == NULL)
                {
                sptr_transit_list = sptr_transit_entry;
                }
            else
                {
                ospf_add_node_to_end_of_list ((OSPF_GENERIC_NODE *) sptr_transit_entry, (OSPF_GENERIC_NODE *) sptr_transit_list);
                }
            }
        }

    return(sptr_transit_list);
    }
/*******************************************************************************//* section 16.3 of OSPF specification (page 158) */
static void ospf_examine_transit_areas_for_better_paths (OSPF_TRANSIT_AREA_ENTRY *sptr_transit_list, OSPF_AREA_ENTRY *sptr_area)
    {
    OSPF_TRANSIT_AREA_ENTRY *sptr_transit_entry;
    OSPF_ADVERTISEMENT_NODE *sptr_advertisement_node;
    OSPF_AREA_ENTRY *sptr_transit_area;

    PARAMETER_NOT_USED (sptr_area);

    OSPF_PRINTF_DEBUG (OSPF_DEBUG_PRINTF, "OSPF: Entering ospf_examine_transit_areas_for_better_paths\r\n");

    for (sptr_transit_entry = sptr_transit_list; sptr_transit_entry != NULL; sptr_transit_entry = sptr_transit_entry->sptr_forward_link)
        {
        for (sptr_advertisement_node = sptr_transit_entry->sptr_area->sptr_summary_advertisement_list_head;
            sptr_advertisement_node != NULL;    sptr_advertisement_node = sptr_advertisement_node->sptr_forward_link)
            {
            sptr_transit_area = sptr_transit_entry->sptr_area;

            ospf_examine_a_single_destination_for_a_better_path (sptr_advertisement_node, sptr_transit_area /*#$-NOTE:note41-$# */ );
            }
        }

    return;
    }

void ospf_examine_a_single_destination_for_a_better_path 

    (
    OSPF_ADVERTISEMENT_NODE *sptr_advertisement_node,
    OSPF_AREA_ENTRY *sptr_area
    )
    {
    ULONG tos0_metric;
    USHORT age;
    ULONG advertising_router;
    ULONG destination_N;
    OSPF_ROUTING_TABLE_ENTRY *sptr_routing_table_entry_for_N;
    OSPF_ROUTING_TABLE_NODE *sptr_routing_table_node_for_N;
    OSPF_ROUTING_TABLE_ENTRY *sptr_routing_table_entry_for_N_saved;
    ULONG area_border_router_BR;
    OSPF_ROUTING_TABLE_ENTRY *sptr_routing_table_entry_for_BR;
    ULONG cost_IAC;
    ULONG area_id;

    OSPF_PRINTF_DEBUG (OSPF_DEBUG_PRINTF, "OSPF: Entering ospf_examine_a_single_destination_for_a_better_path\r\n");

    sptr_routing_table_entry_for_N = NULL;
    sptr_routing_table_entry_for_N_saved = NULL;

    tos0_metric = net_to_host_long (sptr_advertisement_node->advertisement.sptr_summary->tos0_metric);
    tos0_metric = tos0_metric & OSPF_LSInfinity;
    age = net_to_host_short (sptr_advertisement_node->advertisement.sptr_summary->ls_header.age);
    advertising_router = net_to_host_long (sptr_advertisement_node->advertisement.sptr_summary->ls_header.advertising_router);

    if ((tos0_metric == OSPF_LSInfinity) || (age == OSPF_MAXIMUM_AGE) || (advertising_router == ospf.router_id))
        {
        return;                                             /* section 16.3, items (1 & 2) (page 158) */
        }

    destination_N = net_to_host_long (sptr_advertisement_node->advertisement.sptr_summary->ls_header.id);

    /* sptr_routing_table_entry_for_N = ospf_find_routing_table_entry (destination_N, OSPF_DESTINATION_TYPE_WILDCARD,
        OSPF_ROUTE_PATH_TYPE_WILDCARD, NULL); */

    /* Fix for TSR# 297651 (SPR# 83274). Mainly search for any network route with the desired path type which matches
       the specified path type. This execludes searching for any network or router route to avoid
       the bug that a network/host IP address matches a router ID which causes the new network/host
       route not to be installed in ospf routing table*/
    sptr_routing_table_node_for_N = ospf_find_router_or_network_routing_table_node (destination_N, sptr_advertisement_node->advertisement.sptr_summary->ls_header.type, 
                                                                                    OSPF_ROUTE_PATH_TYPE_WILDCARD, NULL);

    if (sptr_routing_table_node_for_N != NULL)
        {
        sptr_routing_table_entry_for_N = sptr_routing_table_node_for_N->sptr_routing_table_entry;
        }

    if (sptr_advertisement_node->advertisement.sptr_summary->ls_header.type == OSPF_LS_SUMMARY_AS_BOUNDARY_ROUTER)
        {
        sptr_routing_table_entry_for_N_saved = sptr_routing_table_entry_for_N;

        sptr_routing_table_entry_for_N = ospf_find_routing_table_entry (destination_N, OSPF_DESTINATION_TYPE_ASBR,
                                                                        OSPF_ROUTE_PATH_TYPE_WILDCARD, NULL);

        if (sptr_routing_table_entry_for_N == NULL)
            {
            ospf_calculate_inter_area_routes_for_a_single_summary_advertisement (sptr_advertisement_node, sptr_area, FALSE);
            }

        sptr_routing_table_entry_for_N = sptr_routing_table_entry_for_N_saved;

        if (sptr_routing_table_entry_for_N == NULL)
            {
            return;
            }
        }
    /*
     * If section 16.5 Case 2, (pages 162-163) FAILS because there is no ABR entry at that point and the hack here is necessary.
     * Need this here to process Transit areas summary links properly.
     */
    if (sptr_routing_table_entry_for_N == NULL)
        {
        ospf_calculate_inter_area_routes_for_a_single_summary_advertisement (sptr_advertisement_node, sptr_area, FALSE);

        return;
        }

    if (sptr_routing_table_entry_for_N->sptr_area != NULL)
        {
        area_id = sptr_routing_table_entry_for_N->sptr_area->area_id;
        }
    else
        {
        area_id = 0xffffffff;
        }

    if ((sptr_routing_table_entry_for_N == NULL) || ((sptr_routing_table_entry_for_N->path_type != OSPF_ROUTE_PATH_TYPE_INTRA) &&
                                                     (sptr_routing_table_entry_for_N->path_type != OSPF_ROUTE_PATH_TYPE_INTER)) ||
        (area_id != OSPF_BACKBONE))
        {
        return;                                             /* section 16.3, item (3) (page 158) */
        }

    area_border_router_BR = advertising_router;

    /* UNH 4.2 start */
    /* For an ABR, there are several ABR routing table entries, one ABR routing table 
    entry for each area the router is attached to.
    The function "ospf_find_routing_table_entry" called here for an ABR in a given area 
    fails to return the proper entry, it returns the ABR entry in another area than the area 
    passed as parameter. The function is also not optimal for ABR entries as it searches for 
    longest fit (as appropriate for IP subnets entries) instead of for exact fit 
    (as appropriate for router entries)
    Use "ospf_find_routing_table_entry_for_ABR" function instead, which searches for 
    ABR entry of a given area (exact fit) */
    /*
    sptr_routing_table_entry_for_BR = ospf_find_routing_table_entry (area_border_router_BR, OSPF_DESTINATION_TYPE_ABR, OSPF_ROUTE_PATH_TYPE_WILDCARD, sptr_area);
    */
    sptr_routing_table_entry_for_BR = ospf_find_routing_table_entry_for_ABR( advertising_router, sptr_area->area_id);
    /* UNH 4.2 end */

    if (sptr_routing_table_entry_for_BR == NULL)
        {