nat_cleanup.c

vxworks NAT 实现部分源代码。有兴趣可以参考下

/* nat_cleanup.c - library that supplies nat_cleanup() */

/* Copyright 2000-2004 Wind River Systems, Inc. */

/* @format.tab-size 4, @format.use-tabs true, @format.new-line lf */

/*
modification history
--------------------
01g,28oct03,zhu  updated NAT hook cleanups
01f,29aug03,zhu  updated the format for refgen
01e,16jun03,myz  Use new fragment translation cleanup routine.
01d,12may03,myz  added natIcmpErrorHookRemove in nat_cleanup.
01c,25apr03,myz  make dllFreeList a global func and add delays in nat_cleanup
01b,24apr03,zhu  updated copyright
01a,21apr03,myz enhanced nat_cleanup function, and added dllFreeList  
040803  vks     updated Copyright info
040303  vks     replaced table_free with free
092502  vvv     modified fragment lists to use lstLib instead of rw_container
092402  vvv     replaced rw_container references with direct linked list
		access to improve performance
030901	tk	Add call to delete natInitSync semaphore
*/

/*
DESCRIPTION

This library provides nat_cleanup(), a routine that you can use to 
shut down WIND NET NAT entirely, thus freeing all its associated 
resources (configuration information, tasks, message queues, etc.).

*/

#include "nat.h"

extern void natIcmpErrorHookRemove (void);
extern void natFilterHooksDelete (void);

/****************************************************************************/

/****************************************************************************/


/****************************************************************************
*
* nat_cleanup - shut down WIND NET NAT, free all associated resources
*
* Call this function to shut down WIND NET NAT entirely and free all its 
* associated resources.  
* 
* 'Note:' To merely pause WIND NET NAT, you can call natEnable() with 
* the <enable> parameter set to FALSE. 
*
*/

void nat_cleanup (void)
{
	IP_TRANSLATION_ENTRY *sptr_ip_translation_entry;

        /* remove the NAT preinput and output filter hooks */

        natFilterHooksDelete();

	/* remove the NAT ICMP error hook */

	natIcmpErrorHookRemove();

	/* give the unhooked NAT engine some time in case it's in progress */

	taskDelay(2);

	/* delete the NAT task */

	natTaskDelete();

	/* cleanup the rest of resource */

	for (sptr_ip_translation_entry = (IP_TRANSLATION_ENTRY *) DLL_FIRST ((DL_LIST *) &nat.natg.ip_translation_list);
		sptr_ip_translation_entry != NULL;
		sptr_ip_translation_entry = (IP_TRANSLATION_ENTRY *) DLL_FIRST ((DL_LIST *) &nat.natg.ip_translation_list))
	{
		dllRemove ((DL_LIST *) &nat.natg.ip_translation_list, (DL_NODE *) sptr_ip_translation_entry);

		if (sptr_ip_translation_entry->sptr_local_address_use_entry != NULL)
		{
			sptr_ip_translation_entry->sptr_local_address_use_entry->address_in_use = FALSE;
		}

		free (sptr_ip_translation_entry);
	}	
	if(nat.pFragTranResrc)
		natFragTranCleanup(nat.pFragTranResrc);

	delete_tcp_connection_entry_list ();

	/* Clean-up passthrough list */
	lstFree (&nat.passthru_list);

	/* Clean-up agent list */
	lstFree (&nat.agent_list);

	/* Clean-up bind list */
	lstFree (&nat.bind_list);

	/* Clean up the semaphores */
	if (udpListLock)
	semDelete (udpListLock);

	if (tcpListLock)
	semDelete (tcpListLock);

	if (spoofingPortLock)
	semDelete (spoofingPortLock);

	if (natInitSync)
	semDelete (natInitSync);

	if (ipListLock)
	semDelete(ipListLock);

	if (bindListLock)
	semDelete(bindListLock);

	if (agentListLock)
	semDelete(agentListLock);
	if(natentrylock)
	semDelete(natentrylock);
	if (nat.natg.global_address_pool != NULL) 
	{
		free (nat.natg.global_address_pool);

		nat.natg.global_address_pool = NULL;
	}

	nat.enabled = FALSE;
}
/************************************************************************/
void delete_sequence_entry_list (SEQUENCE_HEADER *sptr_sequence_list)
{
	dllFreeList ((DL_LIST *) sptr_sequence_list);
}	

/***************************************************************************
*
* dllFreeList - Free a link list
*
* Free a link list.
* 
* NOMANUAL
*/

void dllFreeList 
    (
    DL_LIST * pList
    )
{
	DL_NODE * pNode;
	DL_NODE * pPrevNode;

	pNode = DLL_FIRST(pList);

	while (pNode)
	{
		pPrevNode = pNode;
		pNode = DLL_NEXT(pNode);
		free((void *)pPrevNode);
	}

	dllInit(pList);
}

/************************************************************************/
void delete_tcp_connection_entry_list ()
{
	unsigned long nat_timeisup_count;
	NAT_CURRENCY_TRANSLATION_ENTRY *sptr_tcp_translation_entry=NULL;

	semTake(natentrylock, WAIT_FOREVER);
	for( nat_timeisup_count=0;nat_timeisup_count< MAX_NAT_ENTRYS; nat_timeisup_count++)
	{
		sptr_tcp_translation_entry=&natTabArray[nat_timeisup_count];

			delete_sequence_entry_list (&sptr_tcp_translation_entry->local_sequence_delta_list);

			delete_sequence_entry_list (&sptr_tcp_translation_entry->global_sequence_delta_list);

	}
	semGive(natentrylock);
}