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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_ip.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_ns PORTABLE C */
/* 6.1 */
/* AUTHOR */
/* */
/* Yuxin Zhou, Microsoft Corporation */
/* */
/* DESCRIPTION */
/* */
/* This internal function processes an incoming neighbor solicitation */
/* message. In response to a valid NS message, it also sends out */
/* a neighbor solicitation, and updates the Neighbor Cache. */
/* */
/* INPUT */
/* */
/* ip_ptr IP stack instance */
/* packet_ptr The echo reply packet */
/* */
/* OUTPUT */
/* */
/* None */
/* */
/* CALLS */
/* */
/* tx_mutex_get Obtain exclusive lock (on table) */
/* tx_mutex_put Release exclusive lock */
/* _nx_packet_release Release packet back to pool */
/* _nx_ipv6_packet_send Send IPv6 packet to remote host */
/* _nx_nd_cache_add Add entry to ND cache table */
/* _nx_nd_cache_find_entry Find ND cache entry by IP address*/
/* _nx_icmpv6_send_queued_packets Send packets queued waiting for */
/* physical mapping */
/* _nx_icmpv6_validate_neighbor_message */
/* Validate received ICMPv6 packet */
/* _nx_ip_checksum_compute Compute NS packet ICMP checksum */
/* */
/* CALLED BY */
/* */
/* _nx_icmpv6_process Main ICMPv6 processor */
/* */
/* 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_ns(NX_IP *ip_ptr, NX_PACKET *packet_ptr)
{
NX_ICMPV6_ND *nd_ptr;
NX_ICMPV6_OPTION *option_ptr;
USHORT *mac_addr;
UINT source_unspecified;
UINT error;
UINT option_length;
NX_ICMPV6_HEADER *header_ptr;
NX_IPV6_HEADER *ipv6_header;
UINT SLLA_changed = NX_FALSE;
UINT i;
NXD_IPV6_ADDRESS *interface_addr;
#if defined(NX_DISABLE_ICMPV6_TX_CHECKSUM) || defined(NX_ENABLE_INTERFACE_CAPABILITY) || defined(NX_IPSEC_ENABLE)
UINT compute_checksum = 1;
#endif /* defined(NX_DISABLE_ICMPV6_TX_CHECKSUM) || defined(NX_ENABLE_INTERFACE_CAPABILITY) || defined(NX_IPSEC_ENABLE) */
ULONG dest_address[4];
/* Initialize local variable: assume source address is specified. */
source_unspecified = NX_FALSE;
/* Assume there is no error. */
error = 0;
/* Get a pointer to the ICMP message header. */
/*lint -e{927} -e{826} suppress cast of pointer to pointer, since it is necessary */
header_ptr = (NX_ICMPV6_HEADER *)packet_ptr -> nx_packet_prepend_ptr;
/* Get a pointer to the IPv6 header. */
/*lint -e{927} -e{826} suppress cast of pointer to pointer, since it is necessary */
ipv6_header = (NX_IPV6_HEADER *)packet_ptr -> nx_packet_ip_header;
/* Get a pointer to the Neighbor Discovery message. */
/*lint -e{929} suppress cast of pointer to pointer, since it is necessary */
nd_ptr = (NX_ICMPV6_ND *)header_ptr;
/* Convert target address to host byte order. */
NX_IPV6_ADDRESS_CHANGE_ENDIAN(nd_ptr -> nx_icmpv6_nd_targetAddress);
/* Convert flag field to host byte order. */
NX_CHANGE_ULONG_ENDIAN(nd_ptr -> nx_icmpv6_nd_flag);
/* Validate the packet. */
if (_nx_icmpv6_validate_neighbor_message(packet_ptr) != NX_SUCCESS)
{
error = 1;
}
/* Find whether or not sender is unspecified. If sender is unspecified,
the sender is performing DAD process. */
if (CHECK_UNSPECIFIED_ADDRESS(ipv6_header -> nx_ip_header_source_ip))
{
/* Mark the packet source as nonsolicited. */
source_unspecified = NX_TRUE;
}
/* Find the appropriate interface to send the packet out on, based
on the destination address. */
/* Get a pointer to the first ipv6 address in the interface address list. */
interface_addr = packet_ptr -> nx_packet_address.nx_packet_ipv6_address_ptr;
if (!error)
{
/* Loop to match IP addresses. */
while (interface_addr != NX_NULL)
{
/* Does the current address in the IP interface list match the one in the
ND message header? */
if ((CHECK_IPV6_ADDRESSES_SAME(interface_addr -> nxd_ipv6_address,
nd_ptr -> nx_icmpv6_nd_targetAddress)))
{
/* We're done matching. */
break;
}
/* Get next IPv6 address in the interface address list. */
interface_addr = interface_addr -> nxd_ipv6_address_next;
}
}
if (error || (interface_addr == NX_NULL))
{
#ifndef NX_DISABLE_ICMP_INFO
/* Increment the ICMP invalid packet error. */
ip_ptr -> nx_ip_icmp_invalid_packets++;
#endif /* NX_DISABLE_ICMP_INFO */
/* An error occurred. Release the packet. */
_nx_packet_release(packet_ptr);
return;
}
/* Have find a valid address. */
packet_ptr -> nx_packet_address.nx_packet_ipv6_address_ptr = interface_addr;
/*
* Once we get here, we have two cases:
* (1) Sender is in the DAD process
* (2) Sender wants to find our MAC address.
*
* So first, we need to find out whether or not the source IP address is
* the unspecified address.
*/
if (source_unspecified == NX_TRUE)
{
/* The sender is in DAD process. */
#ifndef NX_DISABLE_IPV6_DAD
/* The sender is doing a DAD on the same address as we have... */
if (interface_addr -> nxd_ipv6_address_state == NX_IPV6_ADDR_STATE_TENTATIVE)
{
/* Our interface address is in tentative state. Therefore interface
address is also invalid. */
_nx_icmpv6_DAD_failure(ip_ptr, interface_addr);
_nx_packet_release(packet_ptr);
return;
}
#endif
/* Our address state is not in tentative mode. That means
we have a valid address. In this case, we should send a response */
}
/* Get a pointer to the ICMPv6 options. */
/*lint -e{923} suppress cast between pointer and ULONG, since it is necessary */
option_ptr = (NX_ICMPV6_OPTION *)NX_UCHAR_POINTER_ADD(header_ptr, sizeof(NX_ICMPV6_ND));
/* We'll need to keep track of option data to parse the options. */
option_length = (UINT)packet_ptr -> nx_packet_length - (UINT)sizeof(NX_ICMPV6_ND);
/* Walk through the ICMPv6 options, if any. */
while (option_length > 0)
{
/* Handle the source link-layer address option for a solicited NS request. */
if (option_ptr -> nx_icmpv6_option_type == ICMPV6_OPTION_TYPE_SRC_LINK_ADDR)
{
ND_CACHE_ENTRY *nd_entry;
UINT status;
/* At this point, the source address has been verified to be
valid (not unspecified.) Therefore we should add
the source link layer address to our neighbor cache. */
/* Is the source IP address is not in our ND cache? */
status = _nx_nd_cache_find_entry(ip_ptr, ipv6_header -> nx_ip_header_source_ip, &nd_entry);
if (status != NX_SUCCESS)
{
/* Yes, this NS fills in the mac address so the LLA is changed. */
SLLA_changed = NX_TRUE;
/* No, so we create a cache entry. */
/*lint -e{929} suppress cast from pointer to pointer, since it is necessary */
/*lint -e{826} suppress cast of pointer to pointer, since it is necessary */
/*lint -e{740} suppress unusual cast of pointer, since it is necessary */
_nx_nd_cache_add(ip_ptr, ipv6_header -> nx_ip_header_source_ip,
interface_addr -> nxd_ipv6_address_attached,
(CHAR *)&option_ptr -> nx_icmpv6_option_data, 0, ND_CACHE_STATE_STALE,
interface_addr, &nd_entry);
}
else
{
/* Entry already exists. If the mac address is the same, do not update the entry. Otherwise,
update the entry and set the state to STALE (RFC2461 7.2.3) */
ULONG mac_msw, mac_lsw, new_msw, new_lsw;
/*lint -e{928} suppress cast from pointer to pointer, since it is necessary */
UCHAR *new_mac = (UCHAR *)&option_ptr -> nx_icmpv6_option_data;
/*lint -e{644} suppress variable might not be initialized, since "nd_entry" was initialized in _nx_nd_cache_find_entry. */
mac_msw = ((ULONG)(nd_entry -> nx_nd_cache_mac_addr[0]) << 8) | (nd_entry -> nx_nd_cache_mac_addr[1]);
mac_lsw = ((ULONG)(nd_entry -> nx_nd_cache_mac_addr[2]) << 24) | ((ULONG)(nd_entry -> nx_nd_cache_mac_addr[3]) << 16) |
((ULONG)(nd_entry -> nx_nd_cache_mac_addr[4]) << 8) | nd_entry -> nx_nd_cache_mac_addr[5];
new_msw = ((ULONG)(new_mac[0]) << 8) | (new_mac[1]);
new_lsw = ((ULONG)(new_mac[2]) << 24) | ((ULONG)(new_mac[3]) << 16) | ((ULONG)(new_mac[4]) << 8) | new_mac[5];
if ((mac_msw != new_msw) || (mac_lsw != new_lsw)) /* If the new MAC is different from what we have in the table. */
{
/* This NS changes the cache entry mac address, so the LLA is changed. */
SLLA_changed = NX_TRUE;
/* Set the mac address. */
for (i = 0; i < 6; i++)
{
nd_entry -> nx_nd_cache_mac_addr[i] = new_mac[i];
}
/* Set the state to STALE. */
nd_entry -> nx_nd_cache_nd_status = ND_CACHE_STATE_STALE;
/* Set the interface. */
nd_entry -> nx_nd_cache_interface_ptr = interface_addr -> nxd_ipv6_address_attached;
}
if (nd_entry -> nx_nd_cache_packet_waiting_head) /* There are packets waiting to be transmitted */
{
/* Ok to transmit the packets now. */
_nx_icmpv6_send_queued_packets(ip_ptr, nd_entry);
}
}
}
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));
}
/* We may need to reset a reachable timer if there is no new LLA involved.
Did we change the cache LLA? */
if (SLLA_changed == NX_FALSE)
{
/* No, so if this cache state is REACHABLE, check if we should
reset the timer tick after receiving a NS packet from the neighbor.
RFC 2461 7.2.3. */
ND_CACHE_ENTRY *nd_entry;
/* Verify the source of the NS packet in our ND cache, in case
we have not already done so. */
if (_nx_nd_cache_find_entry(ip_ptr, ipv6_header -> nx_ip_header_source_ip, &nd_entry) == NX_SUCCESS)
{
/* Yes, is it currently in a reachable state? */
/*lint -e{644} suppress variable might not be initialized, since "nd_entry" was initialized in _nx_nd_cache_find_entry. */
if (nd_entry -> nx_nd_cache_nd_status == ND_CACHE_STATE_REACHABLE)
{
/* Ok to update the timer. */
nd_entry -> nx_nd_cache_timer_tick = ip_ptr -> nx_ipv6_reachable_timer;
}
}
}
/*
* A valid NS has been received. Prepare a Neighbor Advertisement packet
* according to RFC2461 section 7.2.4.
*
* Adjust the packet, eliminate the option part. At this point, the packet prepend_ptr points to the
* beginning of the ICMP message. The size of the ICMP message includes ICMP NA and the target
* link layer address option field (8 bytes).
*/
packet_ptr -> nx_packet_append_ptr =
packet_ptr -> nx_packet_prepend_ptr + sizeof(NX_ICMPV6_ND) + 8;
packet_ptr -> nx_packet_length = sizeof(NX_ICMPV6_ND) + 8;
if (source_unspecified == NX_TRUE)
{
/* Response to an unsolicited NS: clear the S bit.*/
nd_ptr -> nx_icmpv6_nd_flag = (0x20000000);
}
else
{
/* Response to a normal NS: set the S bit.*/
nd_ptr -> nx_icmpv6_nd_flag = (0x60000000);
}
NX_CHANGE_ULONG_ENDIAN(nd_ptr -> nx_icmpv6_nd_flag);
/* nd_ptr -> targetAddress has been converted to host byte order.
We need to convert it back to network byte order. */
NX_IPV6_ADDRESS_CHANGE_ENDIAN(nd_ptr -> nx_icmpv6_nd_targetAddress);
header_ptr -> nx_icmpv6_header_type = NX_ICMPV6_NEIGHBOR_ADVERTISEMENT_TYPE;
header_ptr -> nx_icmpv6_header_code = 0;
header_ptr -> nx_icmpv6_header_checksum = 0;
if (source_unspecified == NX_TRUE)
{
/* Sender uses unspecified address. So we send NA to all node multicast address. */
/* RFC2461 7.2.4 */
dest_address[0] = 0xFF020000;
dest_address[1] = 0;
dest_address[2] = 0;
dest_address[3] = 0x00000001;
}
else
{
/* Set the packet destination IP address */
COPY_IPV6_ADDRESS(ipv6_header -> nx_ip_header_source_ip,
dest_address);
}
/*
Fill in the options. Since we are using the same packet,
the option_ptr is already pointing to 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(header_ptr, sizeof(NX_ICMPV6_ND));
option_ptr -> nx_icmpv6_option_type = ICMPV6_OPTION_TYPE_TRG_LINK_ADDR;
option_ptr -> nx_icmpv6_option_length = 1;
mac_addr = &option_ptr -> nx_icmpv6_option_data;
mac_addr[0] = (USHORT)(interface_addr -> nxd_ipv6_address_attached -> nx_interface_physical_address_msw);
mac_addr[1] = (USHORT)((interface_addr -> nxd_ipv6_address_attached -> nx_interface_physical_address_lsw & 0xFFFF0000) >> 16);
mac_addr[2] = (USHORT)(interface_addr -> nxd_ipv6_address_attached -> nx_interface_physical_address_lsw & 0x0000FFFF);
NX_CHANGE_USHORT_ENDIAN(mac_addr[0]);
NX_CHANGE_USHORT_ENDIAN(mac_addr[1]);
NX_CHANGE_USHORT_ENDIAN(mac_addr[2]);
#ifdef NX_DISABLE_ICMPV6_TX_CHECKSUM
compute_checksum = 0;
#endif /* NX_DISABLE_ICMPV6_TX_CHECKSUM */
#ifdef NX_ENABLE_INTERFACE_CAPABILITY
if (interface_addr -> nxd_ipv6_address_attached -> nx_interface_capability_flag & NX_INTERFACE_CAPABILITY_ICMPV6_TX_CHECKSUM)
{
compute_checksum = 0;
}
#endif /* NX_ENABLE_INTERFACE_CAPABILITY */
#if defined(NX_DISABLE_ICMPV6_TX_CHECKSUM) || defined(NX_ENABLE_INTERFACE_CAPABILITY) || defined(NX_IPSEC_ENABLE)
if (compute_checksum)
#endif /* defined(NX_DISABLE_ICMPV6_TX_CHECKSUM) || defined(NX_ENABLE_INTERFACE_CAPABILITY) || defined(NX_IPSEC_ENABLE) */
{
/* Compute the checksum. */
header_ptr -> nx_icmpv6_header_checksum =
_nx_ip_checksum_compute(packet_ptr, NX_PROTOCOL_ICMPV6,
(UINT)packet_ptr -> nx_packet_length,
interface_addr -> nxd_ipv6_address,
dest_address);
/* Write the checksum to the ICMPv6 header. */
header_ptr -> nx_icmpv6_header_checksum = (USHORT)(~(header_ptr -> nx_icmpv6_header_checksum));
NX_CHANGE_USHORT_ENDIAN(header_ptr -> nx_icmpv6_header_checksum);
}
#ifdef NX_ENABLE_INTERFACE_CAPABILITY
else
{
packet_ptr -> nx_packet_interface_capability_flag |= NX_INTERFACE_CAPABILITY_ICMPV6_TX_CHECKSUM;
}
#endif /* NX_ENABLE_INTERFACE_CAPABILITY */
/* Send out the NA reply. */
_nx_ipv6_packet_send(ip_ptr, packet_ptr,
NX_PROTOCOL_ICMPV6,
packet_ptr -> nx_packet_length,
255 /* NA message must have hop limit 255 */,
interface_addr -> nxd_ipv6_address,
dest_address);
/* (Let the driver release the packet.) */
return;
}
#endif /* FEATURE_NX_IPV6 */
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