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/***************************************************************************
* Copyright (c) 2024 Microsoft Corporation
* Copyright (c) 2025-present Eclipse ThreadX Contributors
*
* This program and the accompanying materials are made available under the
* terms of the MIT License which is available at
* https://opensource.org/licenses/MIT.
*
* SPDX-License-Identifier: MIT
**************************************************************************/
/**************************************************************************/
/**************************************************************************/
/** */
/** NetX Component */
/** */
/** Neighbor Discovery Cache */
/** */
/**************************************************************************/
/**************************************************************************/
#define NX_SOURCE_CODE
/* Include necessary system files. */
#include "nx_api.h"
#include "nx_ipv6.h"
#include "nx_nd_cache.h"
#include "nx_icmpv6.h"
#ifdef FEATURE_NX_IPV6
/**************************************************************************/
/* */
/* FUNCTION RELEASE */
/* */
/* _nx_nd_cache_fast_periodic_update PORTABLE C */
/* 6.4.3 */
/* AUTHOR */
/* */
/* Yuxin Zhou, Microsoft Corporation */
/* */
/* DESCRIPTION */
/* */
/* This function handles the ND entries in PROBE or INCOMPLETE state. */
/* It decrements the timer tick. If the ticker reaches zero */
/* a NS is sent. If MAX NS has been sent, this entry times out */
/* and is marked as INVALID. */
/* */
/* INPUT */
/* */
/* ip_ptr Pointer to the IP instance */
/* */
/* OUTPUT */
/* */
/* NONE */
/* */
/* CALLS */
/* */
/* tx_mutex_get Obtain protection mutex */
/* tx_mutex_put Release protection mutex */
/* _nx_icmpv6_send_ns Transmit a new NS message. */
/* */
/* CALLED BY */
/* */
/* _nx_nd_cache_delete_internal */
/* _nx_ip_thread_entry */
/* tx_mutex_get */
/* tx_mutex_put */
/* */
/* Note: */
/* */
/* This routine acquires the nx_nd_cache_protection mutex. */
/* Caller shall not hold this mutex before calling this function. */
/* */
/* */
/**************************************************************************/
VOID _nx_nd_cache_fast_periodic_update(NX_IP *ip_ptr)
{
INT i;
/* Loop through all entries, and invalidate the ones that are timed out. */
for (i = 0; i < NX_IPV6_NEIGHBOR_CACHE_SIZE; i++)
{
/* Check the entry is valid. */
if (ip_ptr -> nx_ipv6_nd_cache[i].nx_nd_cache_nd_status == ND_CACHE_STATE_INVALID)
{
continue;
}
/* Is this entry being checked for neighbor discovery? */
if ((ip_ptr -> nx_ipv6_nd_cache[i].nx_nd_cache_nd_status != ND_CACHE_STATE_PROBE) &&
(ip_ptr -> nx_ipv6_nd_cache[i].nx_nd_cache_nd_status != ND_CACHE_STATE_INCOMPLETE))
{
/* No, so skip over. */
continue;
}
/* Has this entry timed out? */
if (ip_ptr -> nx_ipv6_nd_cache[i].nx_nd_cache_timer_tick == 0)
{
/* Yes, is the max number of solicitations used up? */
if (ip_ptr -> nx_ipv6_nd_cache[i].nx_nd_cache_num_solicit == 0)
{
/* Yes; We already sent #num_solicit packets. So the destination
is unreachable. Clean up router, destination and cache table entries and crosslinks. */
_nx_nd_cache_delete_internal(ip_ptr, &ip_ptr -> nx_ipv6_nd_cache[i]);
}
else
{
/* Send another solicitation (NS) packet. */
INT uniCastNS;
uniCastNS = (ip_ptr -> nx_ipv6_nd_cache[i].nx_nd_cache_nd_status == ND_CACHE_STATE_PROBE);
/* Send out another mcast ns.*/
_nx_icmpv6_send_ns(ip_ptr, ip_ptr -> nx_ipv6_nd_cache[i].nx_nd_cache_dest_ip,
1, ip_ptr -> nx_ipv6_nd_cache[i].nx_nd_cache_outgoing_address, uniCastNS, &ip_ptr -> nx_ipv6_nd_cache[i]);
/* Keep track of how many we have sent. */
ip_ptr -> nx_ipv6_nd_cache[i].nx_nd_cache_num_solicit--;
/* Reset the expiration timer for sending the next NS. */
ip_ptr -> nx_ipv6_nd_cache[i].nx_nd_cache_timer_tick = ip_ptr -> nx_ipv6_retrans_timer_ticks;
}
}
else
{
/* Note that the only cache entries whose timer ticks are being decremented in this
function are states whose timer tick was set in actual timer ticks (as compared
with the slow periodic update where cache entry'timer ticks' are updated in
seconds. This is intentional and correct behavior. */
ip_ptr -> nx_ipv6_nd_cache[i].nx_nd_cache_timer_tick--;
}
}
}
#endif /* FEATURE_NX_IPV6 */
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