1
0
mirror of https://github.com/FreeRTOS/FreeRTOS-Plus-TCP synced 2025-10-21 15:10:39 +08:00
Files
FreeRTOS-Plus-TCP/source/FreeRTOS_DNS_Cache.c
Aniruddha Kanhere 1ab6eb8885 Update version numbers and licensing info (#541)
* Update source location for coverity

* Add coverage checker

* Add build check with default configuration

* Fix build combination and DNS error

* uncrustified and fixed cmakelists

* This commit updates version number in all files to Development-Branch

* Update version number macros

* This commit fixes a typo in version number macro

* Added a 'critical section' to prevent a race condition in stream buffers

* Uncrustify: triggered by comment.

* Fixed unit-tests by adding mocked functions

* Initial commit of file README.md

* Update README.md

* Fix the title of README file in coverity

* Addressed issue comments

* Update command

* Add details about remaining exception

* Move file to original location

* Remove use of sudo in commands

* Fix links; added coverity version note

* Update README.md

* Remove CMake installation instructions

* Update manifest/history and copyright year

* Update kernel version to 10.4.5

* Update remaining copyright year instances

* Update the version number macros

* Update license header titles

* Remove kernel license header and add TCP header

Co-authored-by: GitHub Action <action@github.com>
Co-authored-by: Gaurav-Aggarwal-AWS <33462878+aggarg@users.noreply.github.com>
2022-08-12 16:21:44 -07:00

372 lines
14 KiB
C

/*
* FreeRTOS+TCP <DEVELOPMENT BRANCH>
* Copyright (C) 2022 Amazon.com, Inc. or its affiliates. All Rights Reserved.
*
* SPDX-License-Identifier: MIT
*
* Permission is hereby granted, free of charge, to any person obtaining a copy of
* this software and associated documentation files (the "Software"), to deal in
* the Software without restriction, including without limitation the rights to
* use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
* the Software, and to permit persons to whom the Software is furnished to do so,
* subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in all
* copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
* FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
* COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
* IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*
* http://aws.amazon.com/freertos
* http://www.FreeRTOS.org
*/
/**
* @file FreeRTOS_DNS_Cache.c
* @brief File that handles the DNS caching option
*/
/* FreeRTOS+TCP includes. */
#include "FreeRTOS_IP.h"
#include "FreeRTOS_Sockets.h"
#include "FreeRTOS_UDP_IP.h"
#include "FreeRTOS_DHCP.h"
#include "NetworkBufferManagement.h"
#include "NetworkInterface.h"
#include "FreeRTOS_DNS_Cache.h"
#include "FreeRTOS_DNS_Globals.h"
/* Standard includes. */
#include <stdint.h>
#include <stdio.h>
#include <string.h>
#if ( ( ipconfigUSE_DNS != 0 ) && ( ipconfigUSE_DNS_CACHE == 1 ) )
/**
* @brief cache entry format structure
*/
typedef struct xDNS_CACHE_TABLE_ROW
{
uint32_t ulIPAddresses[ ipconfigDNS_CACHE_ADDRESSES_PER_ENTRY ]; /*!< The IP address(es) of an ARP cache entry. */
char pcName[ ipconfigDNS_CACHE_NAME_LENGTH ]; /*!< The name of the host */
uint32_t ulTTL; /*!< Time-to-Live (in seconds) from the DNS server. */
uint32_t ulTimeWhenAddedInSeconds; /*!< time at which the entry was added */
#if ( ipconfigDNS_CACHE_ADDRESSES_PER_ENTRY > 1 )
uint8_t ucNumIPAddresses; /*!< number of ip addresses for the same entry */
uint8_t ucCurrentIPAddress; /*!< current ip address index */
#endif
} DNSCacheRow_t;
/*!
* @brief DNS cache structure instantiation
*/
static DNSCacheRow_t xDNSCache[ ipconfigDNS_CACHE_ENTRIES ] = { 0x0 };
/*!
* @brief indicates the index of a free entry in the cache structure
* \a DNSCacheRow_t
*/
static UBaseType_t uxFreeEntry = 0U;
static BaseType_t prvFindEntryIndex( const char * pcName,
UBaseType_t * uxResult );
static BaseType_t prvGetCacheIPEntry( UBaseType_t uxIndex,
uint32_t * pulIP,
uint32_t ulCurrentTimeSeconds );
static void prvUpdateCacheEntry( UBaseType_t uxIndex,
uint32_t ulTTL,
const uint32_t * pulIP,
uint32_t ulCurrentTimeSeconds );
static void prvInsertCacheEntry( const char * pcName,
uint32_t ulTTL,
const uint32_t * pulIP,
uint32_t ulCurrentTimeSeconds );
/**
* @brief perform a dns lookup in the local cache
* @param pcHostName the lookup name
* @return ulIPAddress with the value from the cache else returns a zero if the
* cache is not enabled or the lookup is not successful
* @post the global structure \a xDNSCache might be modified
*/
uint32_t FreeRTOS_dnslookup( const char * pcHostName )
{
uint32_t ulIPAddress = 0U;
( void ) FreeRTOS_ProcessDNSCache( pcHostName,
&ulIPAddress,
0,
pdTRUE );
return ulIPAddress;
}
/**
* @brief perform a dns update in the local cache
* @param pcName the lookup name
* @param pulIP the ip value to insert/replace
* @param ulTTL Time To live (in seconds)
* @return this is a dummy return, we are actually ignoring the return value
* from this function
* @post the global structure \a xDNSCache might be modified
*/
BaseType_t FreeRTOS_dns_update( const char * pcName,
uint32_t * pulIP,
uint32_t ulTTL )
{
( void ) FreeRTOS_ProcessDNSCache( pcName,
pulIP,
ulTTL,
pdFALSE );
return pdTRUE;
}
/**
* @brief perform a dns clear in the local cache
* @post the global structure \a xDNSCache is modified
*/
void FreeRTOS_dnsclear( void )
{
( void ) memset( xDNSCache, 0x0, sizeof( xDNSCache ) );
uxFreeEntry = 0U;
}
/**
* @brief process a DNS Cache request (get, update, or insert)
*
* @param[in] pcName: the name of the host
* @param[in,out] pulIP: when doing a lookup, will be set, when doing an update,
* will be read.
* @param[in] ulTTL: Time To Live (in seconds)
* @param[in] xLookUp: pdTRUE if a look-up is expected, pdFALSE, when the DNS cache must
* be updated.
* @return whether the operation was successful
* @post the global structure \a xDNSCache might be modified
*/
BaseType_t FreeRTOS_ProcessDNSCache( const char * pcName,
uint32_t * pulIP,
uint32_t ulTTL,
BaseType_t xLookUp )
{
UBaseType_t uxIndex;
BaseType_t xResult;
TickType_t xCurrentTickCount = xTaskGetTickCount();
uint32_t ulCurrentTimeSeconds;
configASSERT( ( pcName != NULL ) );
ulCurrentTimeSeconds = ( xCurrentTickCount / portTICK_PERIOD_MS ) / 1000U;
xResult = prvFindEntryIndex( pcName, &uxIndex );
if( xResult == pdTRUE )
{ /* Element found */
if( xLookUp == pdTRUE )
{
/* This statement can only be reached when xResult is true; which
* implies that the entry is present and a 'get' operation will result
* in success. Therefore, it is safe to ignore the return value of the
* below function. */
( void ) prvGetCacheIPEntry( uxIndex,
pulIP,
ulCurrentTimeSeconds );
}
else
{
prvUpdateCacheEntry( uxIndex,
ulTTL,
pulIP,
ulCurrentTimeSeconds );
}
}
else /* Element not Found xResult = pdFALSE */
{
if( xLookUp == pdTRUE )
{
*pulIP = 0U;
}
else
{
prvInsertCacheEntry( pcName,
ulTTL,
pulIP,
ulCurrentTimeSeconds );
}
}
if( ( xLookUp == pdFALSE ) || ( *pulIP != 0U ) )
{
FreeRTOS_debug_printf( ( "FreeRTOS_ProcessDNSCache: %s: '%s' @ %xip (TTL %u)\n",
( xLookUp != 0 ) ? "look-up" : "add",
pcName,
( unsigned ) FreeRTOS_ntohl( *pulIP ),
( unsigned ) FreeRTOS_ntohl( ulTTL ) ) );
}
return xResult;
}
/**
* @brief returns the index of the hostname entry in the dns cache.
* @param[in] pcName find it in the cache
* @param [out] xResult index number
* @returns res pdTRUE if index in found else pdFALSE
*/
static BaseType_t prvFindEntryIndex( const char * pcName,
UBaseType_t * uxResult )
{
BaseType_t xReturn = pdFALSE;
UBaseType_t uxIndex;
/* For each entry in the DNS cache table. */
for( uxIndex = 0; uxIndex < ipconfigDNS_CACHE_ENTRIES; uxIndex++ )
{
if( xDNSCache[ uxIndex ].pcName[ 0 ] == ( char ) 0 )
{ /* empty slot */
continue;
}
if( strcmp( xDNSCache[ uxIndex ].pcName, pcName ) == 0 )
{ /* hostname found */
xReturn = pdTRUE;
*uxResult = uxIndex;
break;
}
}
return xReturn;
}
/**
* @brief get entry at \p index from the cache
* @param[in] uxIndex : index in the cache
* @param[out] pulIP fill it with the result
* @param[in] ulCurrentTimeSeconds current time
* @returns \c pdTRUE if the value is valid \c pdFALSE otherwise
* @post the global structure \a xDNSCache might be modified
*
*/
static BaseType_t prvGetCacheIPEntry( UBaseType_t uxIndex,
uint32_t * pulIP,
uint32_t ulCurrentTimeSeconds )
{
BaseType_t isRead;
uint32_t ulIPAddressIndex = 0;
uint32_t ulAge = ulCurrentTimeSeconds - xDNSCache[ uxIndex ].ulTimeWhenAddedInSeconds;
/* Confirm that the record is still fresh.
* The field ulTTL was stored as network-endian. */
if( ulAge < FreeRTOS_ntohl( xDNSCache[ uxIndex ].ulTTL ) )
{
#if ( ipconfigDNS_CACHE_ADDRESSES_PER_ENTRY > 1 )
uint8_t ucIndex;
/* The ucCurrentIPAddress value increments without bound and will rollover, */
/* modulo it by the number of IP addresses to keep it in range. */
/* Also perform a final modulo by the max number of IP addresses */
/* per DNS cache entry to prevent out-of-bounds access in the event */
/* that ucNumIPAddresses has been corrupted. */
ucIndex = xDNSCache[ uxIndex ].ucCurrentIPAddress % xDNSCache[ uxIndex ].ucNumIPAddresses;
ucIndex = ucIndex % ( uint8_t ) ipconfigDNS_CACHE_ADDRESSES_PER_ENTRY;
ulIPAddressIndex = ucIndex;
xDNSCache[ uxIndex ].ucCurrentIPAddress++;
#endif /* if ( ipconfigDNS_CACHE_ADDRESSES_PER_ENTRY > 1 ) */
*pulIP = xDNSCache[ uxIndex ].ulIPAddresses[ ulIPAddressIndex ];
isRead = pdTRUE;
}
else
{
/* Age out the old cached record. */
xDNSCache[ uxIndex ].pcName[ 0 ] = ( char ) 0;
isRead = pdFALSE;
}
return isRead;
}
/**
* @brief update entry at \p index in the cache
* @param[in] uxIndex : index in the cache
* @param[in] ulTTL time to live (in seconds)
* @param[in] pulIP ip to update the cache with
* @param[in] ulCurrentTimeSeconds current time
* @post the global structure \a xDNSCache is modified
*
*/
static void prvUpdateCacheEntry( UBaseType_t uxIndex,
uint32_t ulTTL,
const uint32_t * pulIP,
uint32_t ulCurrentTimeSeconds )
{
uint32_t ulIPAddressIndex = 0;
#if ( ipconfigDNS_CACHE_ADDRESSES_PER_ENTRY > 1 )
if( xDNSCache[ uxIndex ].ucNumIPAddresses <
( uint8_t ) ipconfigDNS_CACHE_ADDRESSES_PER_ENTRY )
{
/* If more answers exist than there are IP address storage
* slots they will overwrite entry 0 */
ulIPAddressIndex = xDNSCache[ uxIndex ].ucNumIPAddresses;
xDNSCache[ uxIndex ].ucNumIPAddresses++;
}
#endif
xDNSCache[ uxIndex ].ulIPAddresses[ ulIPAddressIndex ] = *pulIP;
xDNSCache[ uxIndex ].ulTTL = ulTTL;
xDNSCache[ uxIndex ].ulTimeWhenAddedInSeconds = ulCurrentTimeSeconds;
}
/**
* @brief insert entry in the cache
* @param[in] pcName cache entry key
* @param[in] ulTTL time to live (in seconds)
* @param[in] pulIP ip address
* @param[in] ulCurrentTimeSeconds current time
* @post the global structure \a xDNSCache is modified
*/
static void prvInsertCacheEntry( const char * pcName,
uint32_t ulTTL,
const uint32_t * pulIP,
uint32_t ulCurrentTimeSeconds )
{
/* Add or update the item. */
if( strlen( pcName ) < ( size_t ) ipconfigDNS_CACHE_NAME_LENGTH )
{
( void ) strcpy( xDNSCache[ uxFreeEntry ].pcName, pcName );
xDNSCache[ uxFreeEntry ].ulIPAddresses[ 0 ] = *pulIP;
xDNSCache[ uxFreeEntry ].ulTTL = ulTTL;
xDNSCache[ uxFreeEntry ].ulTimeWhenAddedInSeconds = ulCurrentTimeSeconds;
#if ( ipconfigDNS_CACHE_ADDRESSES_PER_ENTRY > 1 )
xDNSCache[ uxFreeEntry ].ucNumIPAddresses = 1;
xDNSCache[ uxFreeEntry ].ucCurrentIPAddress = 0;
/* Initialize all remaining IP addresses in this entry to 0 */
( void ) memset( &xDNSCache[ uxFreeEntry ].ulIPAddresses[ 1 ],
0,
sizeof( xDNSCache[ uxFreeEntry ].ulIPAddresses[ 1 ] ) *
( ( uint32_t ) ipconfigDNS_CACHE_ADDRESSES_PER_ENTRY - 1U ) );
#endif
uxFreeEntry++;
if( uxFreeEntry == ipconfigDNS_CACHE_ENTRIES )
{
uxFreeEntry = 0;
}
}
}
#endif /* if ( ( ipconfigUSE_DNS != 0 ) && ( ipconfigUSE_DNS_CACHE == 1 ) ) */