/* ospf_receive_acknowledgement.c *//* Copyright 2000 Wind River Systems, Inc. *//*modification history___________________ 02d,22apr03,ram	   		SPR#76812 Modifications for OSPF performance enhancements 02c,17feb03,ram			SPR 85893 Removed check for pending deletion 02b,29jan03,mwv			SPR 85893 ospf_ls_acknowledgement_packet_received () check pending deletion for                            flag for external routes. 02a,06jan03,ram			SPR 85432 Changes to allow more OSPF external route processing 18,16april02,jkw	  		One copy of external and type 11 lsa 17,19june01,aos   			Calling to ospf_clean_up_retransmit_lists_affiliated_with_this_advertisement () function before freeing the LS database entry. 16,26september00,reshma	Added WindRiver CopyRight 15,25september00,reshma	RFC-1587 implementation for OSPF NSSA Option, also tested against ANVL. 14,07july00,reshma			Unix compatibility related changes. 13,04april00,reshma		Added some MIB support (Read only).Passed all important ANVL OSPF tests. 12,23december99,reshma		Compatibility with VxWorks-IP and VxWorks RTM-interface 11,28december98,jack		Compiled and added some comments 10,11november98,jack		Config changes, linted and big endian changes 09,30october98,jack		Incorporate changes for compilation on Vxworks 08,23august98,jack			ANVL tested OSPF with PATRICIA tree route table and no recursion 07,10august98,jack			PATRICIA Route Table Based OSPF Code Base 06,04june98,jack			Integration with RTM and BGP 05,24april98,jack			RTM changes 04,10july97,cindy			Pre-release v1.52b 03,02october97,cindy		Release Version 1.52 02,22october96,cindy		Release Version 1.50 01,05june96,cindy			First Beta Release*//*DESCRIPTIONospf_receive_acknowledgement.c is used for processing received link state acknowledgement packets.This file is used whenever a new OSPF link state acknowledgement packet is received.*/#include "ospf.h"#if defined (__OSPF_VIRTUAL_STACK__)#include "ospf_vs_lib.h"#endif /* __OSPF_VIRTUAL_STACK__ *//*******************************************************************************************************************************/static void ospf_process_advertisement (OSPF_NEIGHBOR *sptr_neighbor,OSPF_LS_DATABASE_ENTRY *sptr_advertisement,OSPF_LS_HEADER *sptr_ls_advertisement_header);/***************************************************************************************************************************** * for each acknowledgement in the Link State Acknowledgement packet, the following steps are performed: *     (1) Does the advertisement acknowledged have an instance on the Link State retransmission list for the neighbor?  If not, *         examine the next acknowledgement.  Otherwise: *     (2) If the acknowledgement is for the same instance that is contained on the list, remove the item from the list and *         examine the next acknowledgment.  Otherwise: *     (3) Log the questionable acknowledgement, and examine the next one. * ****************************************************************************//* section 13.7 of OSPF specification (page 144) */enum OSPF_PACKET_STATE ospf_ls_acknowledgement_packet_received (OSPF_LS_ACKNOWLEDGEMENT_HEADER *sptr_acknowledgement_packet,	OSPF_NEIGHBOR *sptr_neighbor,OSPF_INTERFACE *sptr_interface,ULONG size_of_packet){	OSPF_LS_HEADER *sptr_ls_advertisement_header;	OSPF_LS_DATABASE_ENTRY *sptr_advertisement;	enum TEST test_return_type;	ULONG link_state_id;	ULONG advertising_router;	OSPF_PRINTF_DEBUG (OSPF_DEBUG_PRINTF, "OSPF: Entering ospf_ls_acknowledgement_packet_received\r\n");	if (sptr_neighbor->state < OSPF_NEIGHBOR_EXCHANGE)		/* discard packet if this neighbor is in a lesser state than Exchange */		{		return (OSPF_ERROR_ACKNOWLEDGEMENT_STATE);		}    if ( sptr_acknowledgement_packet == NULL )        return( OSPF_ERROR_ACKNOWLEDGEMENT_BAD );	sptr_ls_advertisement_header = &sptr_acknowledgement_packet->ls_advertisement_header;	for (size_of_packet -= OSPF_PACKET_SIZE; size_of_packet > 0x00000000L; size_of_packet -= sizeof (OSPF_LS_HEADER))		{		test_return_type = ospf_check_for_valid_ls_type (sptr_interface, sptr_ls_advertisement_header, OSPF_LINK_STATE_ACKNOWLEDGEMENT_PACKET);		if (test_return_type == FAIL)			{			continue;			}		link_state_id = sptr_ls_advertisement_header->id;		link_state_id = net_to_host_long (link_state_id);		advertising_router = sptr_ls_advertisement_header->advertising_router;		advertising_router = net_to_host_long (advertising_router);		/* SPR#76812 */		sptr_advertisement = ospf_find_LSA (sptr_interface->sptr_area, link_state_id, advertising_router, sptr_ls_advertisement_header->type);		if (sptr_advertisement == NULL)			{			continue;							/* couldn't find the acknowledged advertisement in the link state database list, so skip it */			}		else if (sptr_advertisement->sptr_ls_database_retrans == NULL)			{			continue;							/* found advertisement, but no neighbors on its retransmit list, so nothing to do */			}		else			{			ospf_process_advertisement (sptr_neighbor, sptr_advertisement, sptr_ls_advertisement_header);			}		sptr_ls_advertisement_header = (OSPF_LS_HEADER *) ((ULONG) sptr_ls_advertisement_header + OSPF_LS_HEADER_SIZE);		}	return (GOOD_RECEIVE);}/*******************************************************************************************************************************/static void ospf_process_advertisement (OSPF_NEIGHBOR *sptr_neighbor,OSPF_LS_DATABASE_ENTRY *sptr_advertisement,OSPF_LS_HEADER *sptr_ls_advertisement_header){	OSPF_LS_DATABASE_NODE *sptr_retransmission_node;	enum TEST test_return_type;	USHORT age;	ULONG advertising_router;	OSPF_PRINTF_DEBUG (OSPF_DEBUG_PRINTF, "OSPF: Entering ospf_process_advertisement\r\n");	sptr_retransmission_node = ospf_find_advertisement_on_neighbors_retransmit_list (sptr_neighbor, sptr_advertisement);	if (sptr_retransmission_node == NULL)	/* section 13.7, first bullet item (page 144) - couldn't find an instance for the     */		{												/* acknowledged advertisement on the Link State retransmission list for the neighbor, */		return;										/* so skip it.                                                                        */		}    if ( sptr_advertisement->advertisement.sptr_router == NULL )        return;	test_return_type = ospf_check_if_same_instance (sptr_ls_advertisement_header,		&(sptr_advertisement->advertisement.sptr_router->ls_header), sptr_retransmission_node->periodic_retransmit_time_counter);	if (test_return_type == PASS)			/* advertisement has been successfully acknowledged by this neighbor */		{		/*	the advertisement's retransmit list is a list of neighbors that haven't acknowledged the advertisement yet */		ospf_remove_neighbor_from_advertisements_retransmit_list (sptr_advertisement, sptr_neighbor);		/* stop retransmitting the advertisement to this neighbor */		ospf_remove_node_from_neighbors_retransmit_queue (sptr_neighbor, sptr_retransmission_node);		/* if OSPF_MAXIMUM_AGE, self-originated and the retransmit list is empty, then remove advertisement from link state database */		test_return_type = ospf_check_if_advertisements_link_state_id_is_equal_to_one_of_the_routers_own_IP_interface_addresses (			sptr_advertisement->advertisement.sptr_router);		age = sptr_advertisement->advertisement.sptr_router->ls_header.age;		age = net_to_host_short (age);		advertising_router = sptr_advertisement->advertisement.sptr_router->ls_header.advertising_router;		advertising_router = net_to_host_long (advertising_router);		/* SPR 85432 -- Begin */		if ((sptr_advertisement->ls_database_freeme == FALSE) &&			(age >= OSPF_MAXIMUM_AGE) &&			(sptr_advertisement->sptr_ls_database_retrans == NULL) &&			(ospf.number_of_neighbors_in_exchange_state == ospf.number_of_neighbors_in_full_state))		/* section 14 (page 145) */			{				sptr_advertisement->ls_database_freeme = TRUE;				ospf_clean_up_retransmit_lists_affiliated_with_this_advertisement (sptr_advertisement);				(void) ospf_free_database_entry (sptr_advertisement);			}		/* SPR 85432 -- End */		}	else		{		if (ospf_check_if_more_recent (sptr_ls_advertisement_header, &sptr_advertisement->advertisement.sptr_router->ls_header,			sptr_retransmission_node->periodic_retransmit_time_counter))			{			OSPF_PRINTF_ALARM (OSPF_ALARM_PRINTF, "OSPF: BAD ACKNOWLEDGEMENT\r\n");			}		else			{			OSPF_PRINTF_ALARM (OSPF_ALARM_PRINTF, "OSPF: DUPLICATE ACKNOWLEDGEMENT\r\n");			}		}	return;}