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/**************************************************************************/
/* */
/* Copyright (c) Microsoft Corporation. All rights reserved. */
/* */
/* This software is licensed under the Microsoft Software License */
/* Terms for Microsoft Azure RTOS. Full text of the license can be */
/* found in the LICENSE file at https://aka.ms/AzureRTOS_EULA */
/* and in the root directory of this software. */
/* */
/**************************************************************************/
/**************************************************************************/
/**************************************************************************/
/** */
/** NetX Component */
/** */
/** Internet Control Message Protocol (ICMP) */
/** */
/**************************************************************************/
/**************************************************************************/
#define NX_SOURCE_CODE
/* Include necessary system files. */
#include "nx_api.h"
#include "nx_packet.h"
#include "nx_ipv6.h"
#include "nx_icmpv6.h"
#ifdef NX_IPSEC_ENABLE
#include "nx_ipsec.h"
#endif /* NX_IPSEC_ENABLE */
#ifdef FEATURE_NX_IPV6
/**************************************************************************/
/* */
/* FUNCTION RELEASE */
/* */
/* _nx_icmpv6_process_na PORTABLE C */
/* 6.1 */
/* AUTHOR */
/* */
/* Yuxin Zhou, Microsoft Corporation */
/* */
/* DESCRIPTION */
/* */
/* This internal function processes incoming neighbor advertisement */
/* messages. It also updates the ND cache and the default router list. */
/* */
/* INPUT */
/* */
/* ip_ptr IP stack instance */
/* packet_ptr Received NA packet */
/* */
/* OUTPUT */
/* */
/* None */
/* */
/* CALLS */
/* */
/* _nx_packet_release Release packet back to pool */
/* _nx_nd_cache_add Add entry to cache table */
/* _nx_icmpv6_send_queued_packets Send out packets queued waiting */
/* for physical mapping to IP */
/* address */
/* _nx_icmpv6_validate_neighbor_message Validate ICMPv6 packet */
/* _nx_icmpv6_DAD_failure Mark IP address status invalid */
/* _nx_nd_cache_find_entry Find entry based on dest address*/
/* _nxd_ipv6_find_default_router_from_address */
/* Find default router by address */
/* _nxd_ipv6_default_router_delete Clear the default router bound */
/* to the IP */
/* */
/* CALLED BY */
/* */
/* _nx_icmpv6_process */
/* */
/* RELEASE HISTORY */
/* */
/* DATE NAME DESCRIPTION */
/* */
/* 05-19-2020 Yuxin Zhou Initial Version 6.0 */
/* 09-30-2020 Yuxin Zhou Modified comment(s), */
/* resulting in version 6.1 */
/* */
/**************************************************************************/
VOID _nx_icmpv6_process_na(NX_IP *ip_ptr, NX_PACKET *packet_ptr)
{
ND_CACHE_ENTRY *nd_entry = NX_NULL;
/*lint -e{927} -e{826} suppress cast of pointer to pointer, since it is necessary */
NX_ICMPV6_ND *nd_ptr = (NX_ICMPV6_ND *)(packet_ptr -> nx_packet_prepend_ptr);
NX_ICMPV6_OPTION *option_ptr = NX_NULL;
INT error = 0;
INT lla_same = 0;
UINT option_length;
NX_IPV6_HEADER *ipv6_header_ptr;
#ifndef NX_DISABLE_IPV6_DAD
UINT i;
#endif /* NX_DISABLE_IPV6_DAD */
/* Add debug information. */
NX_PACKET_DEBUG(__FILE__, __LINE__, packet_ptr);
/* Take care of endian-ness. */
NX_IPV6_ADDRESS_CHANGE_ENDIAN(nd_ptr -> nx_icmpv6_nd_targetAddress);
NX_CHANGE_ULONG_ENDIAN(nd_ptr -> nx_icmpv6_nd_flag);
/* Validate the neighbor advertisement message. */
if (_nx_icmpv6_validate_neighbor_message(packet_ptr) != NX_SUCCESS)
{
error = 1;
}
else
{
/* Points to the IPv6 header. */
/*lint -e{927} -e{826} suppress cast of pointer to pointer, since it is necessary */
ipv6_header_ptr = (NX_IPV6_HEADER *)packet_ptr -> nx_packet_ip_header;
/* Find the option field. */
/*lint -e{923} suppress cast between pointer and ULONG, since it is necessary */
option_ptr = (NX_ICMPV6_OPTION *)NX_UCHAR_POINTER_ADD(nd_ptr, sizeof(NX_ICMPV6_ND));
option_length = (UINT)packet_ptr -> nx_packet_length - (UINT)sizeof(NX_ICMPV6_ND);
/* Find the TLLA option */
while (option_length > 0)
{
/* Check if this is a Target LLA option. */
if (option_ptr -> nx_icmpv6_option_type == ICMPV6_OPTION_TYPE_TRG_LINK_ADDR)
{
break;
}
/* Get the next option. */
option_length -= ((UINT)(option_ptr -> nx_icmpv6_option_length) << 3);
/*lint -e{923} suppress cast between pointer and ULONG, since it is necessary */
option_ptr = (NX_ICMPV6_OPTION *)NX_UCHAR_POINTER_ADD(option_ptr, ((option_ptr -> nx_icmpv6_option_length) << 3));
}
/* Check for no option included. */
if (option_length == 0)
{
option_ptr = NX_NULL;
}
/* Determine the NA packet destination type. */
/* Is the destination a multicast address? */
if ((ipv6_header_ptr -> nx_ip_header_destination_ip[0] & (ULONG)0xFF000000) == (ULONG)0xFF000000)
{
/* Yes; Were there any options in the NA packet? */
if (!option_ptr)
{
/* No, this is an invalid NA packet (No TLLA). */
error = 1;
}
}
#ifndef NX_DISABLE_IPV6_DAD
/* Find the same address as target address in IPv6 address structure.
Assume target address is 4-byte aligned.*/
for (i = 0; i < NX_MAX_IPV6_ADDRESSES; i++)
{
if (CHECK_IPV6_ADDRESSES_SAME(ip_ptr -> nx_ipv6_address[i].nxd_ipv6_address,
nd_ptr -> nx_icmpv6_nd_targetAddress))
{
if (ip_ptr -> nx_ipv6_address[i].nxd_ipv6_address_state == NX_IPV6_ADDR_STATE_TENTATIVE)
{
/* Sender sends a NS in response to a DAD request we sent out.
Mark DAD failure. */
_nx_icmpv6_DAD_failure(ip_ptr, &ip_ptr -> nx_ipv6_address[i]);
#ifndef NX_DISABLE_ICMP_INFO
/* Increment the ICMP invalid packet error. */
ip_ptr -> nx_ip_icmp_invalid_packets++;
#endif /* NX_DISABLE_ICMP_INFO */
/* Release the packet and we are done. */
_nx_packet_release(packet_ptr);
return;
}
break;
}
}
#endif /* NX_DISABLE_IPV6_DAD */
/* Find the ND entry */
if (_nx_nd_cache_find_entry(ip_ptr, nd_ptr -> nx_icmpv6_nd_targetAddress, &nd_entry) != NX_SUCCESS)
{
/* The entry does not exist, it indicates that we are not
expecting this NA. So silently ignore this packet,
according to RFC 2461 7.2.5 */
error = 1;
}
}
/* Do not process the NA any further if any errors detected. */
if (error)
{
#ifndef NX_DISABLE_ICMP_INFO
/* Increment the ICMP invalid packet error. */
ip_ptr -> nx_ip_icmp_invalid_packets++;
#endif /* NX_DISABLE_ICMP_INFO */
/* Release the packet and we are done. */
_nx_packet_release(packet_ptr);
return;
}
/* Check whether or not supplied LLA is the same as the cached one */
if (option_ptr)
{
/* Compare the link-layer address. */
USHORT *new_lla, *lla;
/*lint -e{929} suppress cast of pointer to pointer, since it is necessary */
new_lla = (USHORT *)&option_ptr -> nx_icmpv6_option_data;
/*lint -e{927} suppress cast of pointer to pointer, since it is necessary */
/*lint -e{644} suppress variable might not be initialized, since "nd_entry" was initialized in _nx_nd_cache_find_entry. */
lla = (USHORT *)nd_entry -> nx_nd_cache_mac_addr;
if ((new_lla[0] == lla[0]) && (new_lla[1] == lla[1]) && (new_lla[2] == lla[2]))
{
/* No change in LLA. */
lla_same = 1;
}
}
/* Determine if the entry is a router. */
if (nd_ptr -> nx_icmpv6_nd_flag & 0x80000000)
{
/* Yes; Does the corresonding ND entry have the IsRouter flag set? */
if (nd_entry -> nx_nd_cache_is_router == NX_NULL)
{
NX_IPV6_DEFAULT_ROUTER_ENTRY *rt_entry;
/* No; Find the default router entry. */
rt_entry =
_nxd_ipv6_find_default_router_from_address(ip_ptr, nd_ptr -> nx_icmpv6_nd_targetAddress);
/* Check the default router. */
if (rt_entry)
{
/* Set the IsRouter flag in the ND entry. */
nd_entry -> nx_nd_cache_is_router = rt_entry;
/* Set this link as the corresponding ND entry. */
rt_entry -> nx_ipv6_default_router_entry_neighbor_cache_ptr = (VOID *)nd_entry;
}
}
}
else
{
/*
* The neighbor advertisement message indicates that it is not a router.
* However if our ND cache still marks it as a router, that means the neighbor is
* no longer acting as a router, and we shall clean up our records.
*/
if (nd_entry -> nx_nd_cache_is_router)
{
NXD_ADDRESS router_address;
UINT clear_router_flag = 1;
/* Only if the TLLA option indicates the TLLA is unchanged! */
if (option_ptr && !lla_same)
{
/* And only if the override bit not is set. */
if ((nd_ptr -> nx_icmpv6_nd_flag & 0x20000000) == 0)
{
clear_router_flag = 0;
}
}
/* Did we decide to clear the router status of this cache entry? */
if (clear_router_flag)
{
/* Yes, Ok to clear the cache entry router status! */
/* The IsRouter points to the entry in the default router table.
We first remove the link between the router table entry and the nd cache entry. */
nd_entry -> nx_nd_cache_is_router -> nx_ipv6_default_router_entry_neighbor_cache_ptr = NX_NULL;
/* Remove the entry from the default router list. */
router_address.nxd_ip_version = NX_IP_VERSION_V6;
router_address.nxd_ip_address.v6[0] = nd_ptr -> nx_icmpv6_nd_targetAddress[0];
router_address.nxd_ip_address.v6[1] = nd_ptr -> nx_icmpv6_nd_targetAddress[1];
router_address.nxd_ip_address.v6[2] = nd_ptr -> nx_icmpv6_nd_targetAddress[2];
router_address.nxd_ip_address.v6[3] = nd_ptr -> nx_icmpv6_nd_targetAddress[3];
/* We must remove the entry from the default router list. */
_nxd_ipv6_default_router_delete(ip_ptr, &router_address);
/* Set the router flag to NULL. */
nd_entry -> nx_nd_cache_is_router = NX_NULL;
}
}
}
/*
* An ND entry exists. If the cache entry is in incomplete state,
* add the NA contains LLA option, if the NA is unsolicitated,
* add the LLA to the cache in STALE state.
*/
if ((nd_entry -> nx_nd_cache_nd_status == ND_CACHE_STATE_INCOMPLETE) ||
(nd_entry -> nx_nd_cache_nd_status == ND_CACHE_STATE_CREATED))
{
/* Find the target link layer options. */
if (option_ptr)
{
/* If the solicitation flag is set, set state to REACHABLE; if not,
set state to STALE.*/
/*lint -e{929} -e{740} -e{826} suppress cast of pointer to pointer, since it is necessary */
_nx_nd_cache_add(ip_ptr, nd_ptr -> nx_icmpv6_nd_targetAddress,
packet_ptr -> nx_packet_address.nx_packet_ipv6_address_ptr -> nxd_ipv6_address_attached,
(CHAR *)&option_ptr -> nx_icmpv6_option_data, 0,
nd_ptr -> nx_icmpv6_nd_flag & 0x40000000 ? ND_CACHE_STATE_REACHABLE : ND_CACHE_STATE_STALE,
packet_ptr -> nx_packet_address.nx_packet_ipv6_address_ptr, &nd_entry);
/* Any queued packets?. */
if (nd_entry -> nx_nd_cache_packet_waiting_head)
{
/* Send the queued packets out. */
_nx_icmpv6_send_queued_packets(ip_ptr, nd_entry);
}
}
/* All done. Release the packet and return. */
_nx_packet_release(packet_ptr);
return;
}
/* When we get there, we have an ND entry that has valid (REACHABLE) LLA. */
if ((nd_ptr -> nx_icmpv6_nd_flag & 0x20000000) == 0 && option_ptr && (!lla_same))
{
/*
* Override bit is clear.
* If the link layer address is different from the one in our cache entry,
* and the entry is REACHABLE, update the entry to STALE.
*/
if (nd_entry -> nx_nd_cache_nd_status == ND_CACHE_STATE_REACHABLE)
{
nd_entry -> nx_nd_cache_nd_status = ND_CACHE_STATE_STALE;
nd_entry -> nx_nd_cache_timer_tick = 0;
}
}
else
{
/* Processing according to RFC2461 7.2.5. */
/* If LLA is supplied and is different from cache value, update the cache. */
if (option_ptr && !lla_same)
{
USHORT *new_lla, *lla;
/*lint -e{929} -e{927} suppress cast of pointer to pointer, since it is necessary */
new_lla = (USHORT *)&option_ptr -> nx_icmpv6_option_data;
/*lint -e{927} suppress cast of pointer to pointer, since it is necessary */
lla = (USHORT *)nd_entry -> nx_nd_cache_mac_addr;
lla[0] = new_lla[0];
lla[1] = new_lla[1];
lla[2] = new_lla[2];
}
if (nd_ptr -> nx_icmpv6_nd_flag & 0x40000000) /* S bit is set, force cache entry to REACHABLE */
{
nd_entry -> nx_nd_cache_nd_status = ND_CACHE_STATE_REACHABLE;
nd_entry -> nx_nd_cache_timer_tick = ip_ptr -> nx_ipv6_reachable_timer;
}
else if (option_ptr && (!lla_same)) /* S bit is clear and either TLLA is not supplied or it is different. */
{
nd_entry -> nx_nd_cache_nd_status = ND_CACHE_STATE_STALE;
nd_entry -> nx_nd_cache_timer_tick = 0;
}
}
_nx_packet_release(packet_ptr);
return;
}
#endif /* FEATURE_NX_IPV6 */
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