3party/mongoose
0
0
Fork 0
mirror of https://github.com/cesanta/mongoose.git synced 2024-12-31 01:13:01 +08:00
Code Issues Projects Releases Wiki Activity
mongoose/test/freertos-tcp/FreeRTOS_DNS.c

2121 lines
90 KiB
C
Raw Normal View History

First stab
2021-05-11 09:12:06 +01:00
/*
* FreeRTOS+TCP V2.3.2
* Copyright (C) 2020 Amazon.com, Inc. or its affiliates. All Rights Reserved.
*
* 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.c
* @brief Implements the Domain Name System for the FreeRTOS+TCP network stack.
*/
/* Standard includes. */
#include <stdint.h>
#include <stdio.h>
/* FreeRTOS includes. */
#include "FreeRTOS.h"
#include "task.h"
#include "semphr.h"
/* FreeRTOS+TCP includes. */
#include "FreeRTOS_IP.h"
#include "FreeRTOS_Sockets.h"
#include "FreeRTOS_IP_Private.h"
#include "FreeRTOS_UDP_IP.h"
#include "FreeRTOS_DNS.h"
#include "FreeRTOS_DHCP.h"
#include "NetworkBufferManagement.h"
#include "NetworkInterface.h"
/* Exclude the entire file if DNS is not enabled. */
#if ( ipconfigUSE_DNS != 0 )
#if ( ipconfigBYTE_ORDER == pdFREERTOS_LITTLE_ENDIAN )
#define dnsDNS_PORT 0x3500U /**< Little endian: Port used for DNS. */
#define dnsONE_QUESTION 0x0100U /**< Little endian representation of a DNS question.*/
#define dnsOUTGOING_FLAGS 0x0001U /**< Little endian representation of standard query. */
#define dnsRX_FLAGS_MASK 0x0f80U /**< Little endian: The bits of interest in the flags field of incoming DNS messages. */
#define dnsEXPECTED_RX_FLAGS 0x0080U /**< Little Endian: Should be a response, without any errors. */
#else
#define dnsDNS_PORT 0x0035U /**< Big endian: Port used for DNS. */
#define dnsONE_QUESTION 0x0001U /**< Big endian representation of a DNS question.*/
#define dnsOUTGOING_FLAGS 0x0100U /**< Big endian representation of standard query. */
#define dnsRX_FLAGS_MASK 0x800fU /**< Big endian: The bits of interest in the flags field of incoming DNS messages. */
#define dnsEXPECTED_RX_FLAGS 0x8000U /**< Big endian: Should be a response, without any errors. */
#endif /* ipconfigBYTE_ORDER */
/** @brief The maximum number of times a DNS request should be sent out if a response
* is not received, before giving up. */
#ifndef ipconfigDNS_REQUEST_ATTEMPTS
#define ipconfigDNS_REQUEST_ATTEMPTS 5
#endif
/** @brief If the top two bits in the first character of a name field are set then the
* name field is an offset to the string, rather than the string itself. */
#define dnsNAME_IS_OFFSET ( ( uint8_t ) 0xc0 )
/* NBNS flags. */
#if ( ipconfigUSE_NBNS == 1 )
#define dnsNBNS_FLAGS_RESPONSE 0x8000U /**< NBNS response flag. */
#define dnsNBNS_FLAGS_OPCODE_MASK 0x7800U /**< NBNS opcode bitmask. */
#define dnsNBNS_FLAGS_OPCODE_QUERY 0x0000U /**< NBNS opcode query. */
#endif /* ( ipconfigUSE_NBNS == 1 ) */
/* Host types. */
#define dnsTYPE_A_HOST 0x01U /**< DNS type A host. */
#define dnsCLASS_IN 0x01U /**< DNS class IN (Internet). */
#ifndef _lint
/* LLMNR constants. */
#define dnsLLMNR_TTL_VALUE 300000UL /**< LLMNR time to live value. */
#define dnsLLMNR_FLAGS_IS_REPONSE 0x8000U /**< LLMNR flag value for response. */
#endif /* _lint */
/* NBNS constants. */
#if ( ipconfigUSE_NBNS != 0 )
#define dnsNBNS_TTL_VALUE 3600UL /**< NBNS TTL: 1 hour valid. */
#define dnsNBNS_TYPE_NET_BIOS 0x0020U /**< NBNS Type: NetBIOS. */
#define dnsNBNS_CLASS_IN 0x01U /**< NBNS Class: IN (Internet). */
#define dnsNBNS_NAME_FLAGS 0x6000U /**< NBNS name flags. */
#define dnsNBNS_ENCODED_NAME_LENGTH 32 /**< NBNS encoded name length. */
/** @brief If the queried NBNS name matches with the device's name,
* the query will be responded to with these flags: */
#define dnsNBNS_QUERY_RESPONSE_FLAGS ( 0x8500U )
#endif /* ( ipconfigUSE_NBNS != 0 ) */
/** @brief Flag DNS parsing errors in situations where an IPv4 address is the return
* type. */
#define dnsPARSE_ERROR 0UL
#ifndef _lint
#if ( ipconfigUSE_DNS_CACHE == 0 )
#if ( ipconfigDNS_CACHE_ADDRESSES_PER_ENTRY != 1 )
#error When DNS caching is disabled, please make ipconfigDNS_CACHE_ADDRESSES_PER_ENTRY equal to 1.
#endif
#endif
#endif
/** @brief Define the ASCII value of '.' (Period/Full-stop). */
#define ASCII_BASELINE_DOT 46U
/*
* Create a socket and bind it to the standard DNS port number. Return the
* the created socket - or NULL if the socket could not be created or bound.
*/
static Socket_t prvCreateDNSSocket( void );
/*
* Create the DNS message in the zero copy buffer passed in the first parameter.
*/
_static size_t prvCreateDNSMessage( uint8_t * pucUDPPayloadBuffer,
const char * pcHostName,
TickType_t uxIdentifier );
/*
* Simple routine that jumps over the NAME field of a resource record.
* It returns the number of bytes read.
*/
_static size_t prvSkipNameField( const uint8_t * pucByte,
size_t uxLength );
/*
* Process a response packet from a DNS server.
* The parameter 'xExpected' indicates whether the identifier in the reply
* was expected, and thus if the DNS cache may be updated with the reply.
*/
_static uint32_t prvParseDNSReply( uint8_t * pucUDPPayloadBuffer,
size_t uxBufferLength,
BaseType_t xExpected );
/*
* Check if hostname is already known. If not, call prvGetHostByName() to send a DNS request.
*/
#if ( ipconfigDNS_USE_CALLBACKS == 1 )
static uint32_t prvPrepareLookup( const char * pcHostName,
FOnDNSEvent pCallback,
void * pvSearchID,
TickType_t uxTimeout );
#else
static uint32_t prvPrepareLookup( const char * pcHostName );
#endif
/*
* Prepare and send a message to a DNS server. 'uxReadTimeOut_ticks' will be passed as
* zero, in case the user has supplied a call-back function.
*/
static uint32_t prvGetHostByName( const char * pcHostName,
TickType_t uxIdentifier,
TickType_t uxReadTimeOut_ticks );
#if ( ipconfigDNS_USE_CALLBACKS != 0 )
static void vDNSSetCallBack( const char * pcHostName,
void * pvSearchID,
FOnDNSEvent pCallbackFunction,
TickType_t uxTimeout,
TickType_t uxIdentifier );
#endif /* ipconfigDNS_USE_CALLBACKS */
#if ( ipconfigDNS_USE_CALLBACKS != 0 )
static BaseType_t xDNSDoCallback( TickType_t uxIdentifier,
const char * pcName,
uint32_t ulIPAddress );
#endif /* ipconfigDNS_USE_CALLBACKS */
/*
* The NBNS and the LLMNR protocol share this reply function.
*/
#if ( ( ipconfigUSE_NBNS == 1 ) || ( ipconfigUSE_LLMNR == 1 ) )
static void prvReplyDNSMessage( NetworkBufferDescriptor_t * pxNetworkBuffer,
BaseType_t lNetLength );
#endif
#if ( ipconfigUSE_NBNS == 1 )
static portINLINE void prvTreatNBNS( uint8_t * pucPayload,
size_t uxBufferLength,
uint32_t ulIPAddress );
#endif /* ipconfigUSE_NBNS */
#if ( ipconfigUSE_DNS_CACHE == 1 ) || ( ipconfigDNS_USE_CALLBACKS == 1 )
_static size_t prvReadNameField( const uint8_t * pucByte,
size_t uxRemainingBytes,
char * pcName,
size_t uxDestLen );
#endif /* ipconfigUSE_DNS_CACHE || ipconfigDNS_USE_CALLBACKS */
#if ( ipconfigUSE_DNS_CACHE == 1 )
static BaseType_t prvProcessDNSCache( const char * pcName,
uint32_t * pulIP,
uint32_t ulTTL,
BaseType_t xLookUp );
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;
#if ( ipconfigDNS_CACHE_ADDRESSES_PER_ENTRY > 1 )
uint8_t ucNumIPAddresses;
uint8_t ucCurrentIPAddress;
#endif
} DNSCacheRow_t;
static DNSCacheRow_t xDNSCache[ ipconfigDNS_CACHE_ENTRIES ];
/* Utility function: Clear DNS cache by calling this function. */
void FreeRTOS_dnsclear( void )
{
( void ) memset( xDNSCache, 0x0, sizeof( xDNSCache ) );
}
#endif /* ipconfigUSE_DNS_CACHE == 1 */
#if ( ipconfigUSE_LLMNR == 1 )
/** @brief The MAC address used for LLMNR. */
const MACAddress_t xLLMNR_MacAdress = { { 0x01, 0x00, 0x5e, 0x00, 0x00, 0xfc } };
#endif /* ipconfigUSE_LLMNR == 1 */
/*-----------------------------------------------------------*/
/* Below #include just tells the compiler to pack the structure.
* It is included in to make the code more readable */
#include "pack_struct_start.h"
struct xDNSMessage
{
uint16_t usIdentifier; /**< Query identifier. Used to match up replies to outstanding queries. */
uint16_t usFlags; /**< Flags. */
uint16_t usQuestions; /**< Number of questions asked in this query. */
uint16_t usAnswers; /**< Number of answers being provided in this query. */
uint16_t usAuthorityRRs; /**< Authoritative name server resource records. */
uint16_t usAdditionalRRs; /**< Additional resource records.*/
}
#include "pack_struct_end.h"
typedef struct xDNSMessage DNSMessage_t;
/**
* @brief Utility function to cast pointer of a type to pointer of type DNSMessage_t.
*
* @return The casted pointer.
*/
static portINLINE ipDECL_CAST_PTR_FUNC_FOR_TYPE( DNSMessage_t )
{
return ( DNSMessage_t * ) pvArgument;
}
/**
* @brief Utility function to cast a const pointer of a type to a const pointer of type DNSMessage_t.
*
* @return The casted pointer.
*/
static portINLINE ipDECL_CAST_CONST_PTR_FUNC_FOR_TYPE( DNSMessage_t )
{
return ( const DNSMessage_t * ) pvArgument;
}
/* A DNS query consists of a header, as described in 'struct xDNSMessage'
* It is followed by 1 or more queries, each one consisting of a name and a tail,
* with two fields: type and class
*/
#include "pack_struct_start.h"
struct xDNSTail
{
uint16_t usType; /**< Type of DNS message. */
uint16_t usClass; /**< Class of DNS message. */
}
#include "pack_struct_end.h"
typedef struct xDNSTail DNSTail_t;
/**
* @brief Utility function to cast pointer of a type to pointer of type DNSTail_t.
*
* @return The casted pointer.
*/
static portINLINE ipDECL_CAST_PTR_FUNC_FOR_TYPE( DNSTail_t )
{
return ( DNSTail_t * ) pvArgument;
}
/* DNS answer record header. */
#include "pack_struct_start.h"
struct xDNSAnswerRecord
{
uint16_t usType; /**< Type of DNS answer record. */
uint16_t usClass; /**< Class of DNS answer record. */
uint32_t ulTTL; /**< Number of seconds the result can be cached. */
uint16_t usDataLength; /**< Length of the data field. */
}
#include "pack_struct_end.h"
typedef struct xDNSAnswerRecord DNSAnswerRecord_t;
/**
* @brief Utility function to cast pointer of a type to pointer of type DNSAnswerRecord_t.
*
* @return The casted pointer.
*/
static portINLINE ipDECL_CAST_PTR_FUNC_FOR_TYPE( DNSAnswerRecord_t )
{
return ( DNSAnswerRecord_t * ) pvArgument;
}
#if ( ipconfigUSE_LLMNR == 1 )
#include "pack_struct_start.h"
struct xLLMNRAnswer
{
uint8_t ucNameCode; /**< Name type. */
uint8_t ucNameOffset; /**< The name is not repeated in the answer, only the offset is given with "0xc0 <offs>" */
uint16_t usType; /**< Type of the Resource record. */
uint16_t usClass; /**< Class of the Resource record. */
uint32_t ulTTL; /**< Seconds till this entry can be cached. */
uint16_t usDataLength; /**< Length of the address in this record. */
uint32_t ulIPAddress; /**< The IP-address. */
}
#include "pack_struct_end.h"
typedef struct xLLMNRAnswer LLMNRAnswer_t;
/**
* @brief Utility function to cast pointer of a type to pointer of type LLMNRAnswer_t.
*
* @return The casted pointer.
*/
static portINLINE ipDECL_CAST_PTR_FUNC_FOR_TYPE( LLMNRAnswer_t )
{
return ( LLMNRAnswer_t * ) pvArgument;
}
#endif /* ipconfigUSE_LLMNR == 1 */
#if ( ipconfigUSE_NBNS == 1 )
#include "pack_struct_start.h"
struct xNBNSRequest
{
uint16_t usRequestId; /**< NBNS request ID. */
uint16_t usFlags; /**< Flags of the DNS message. */
uint16_t ulRequestCount; /**< The number of requests/questions in this query. */
uint16_t usAnswerRSS; /**< The number of answers in this query. */
uint16_t usAuthRSS; /**< Number of authoritative resource records. */
uint16_t usAdditionalRSS; /**< Number of additional resource records. */
uint8_t ucNameSpace; /**< Length of name. */
uint8_t ucName[ dnsNBNS_ENCODED_NAME_LENGTH ]; /**< The domain name. */
uint8_t ucNameZero; /**< Terminator of the name. */
uint16_t usType; /**< Type of NBNS record. */
uint16_t usClass; /**< Class of NBNS request. */
}
#include "pack_struct_end.h"
typedef struct xNBNSRequest NBNSRequest_t;
#include "pack_struct_start.h"
struct xNBNSAnswer
{
uint16_t usType; /**< Type of NBNS answer. */
uint16_t usClass; /**< Class of NBNS answer. */
uint32_t ulTTL; /**< Time in seconds for which the answer can be cached. */
uint16_t usDataLength; /**< Data length. */
uint16_t usNbFlags; /**< NetBIOS flags 0x6000 : IP-address, big-endian. */
uint32_t ulIPAddress; /**< The IPv4 address. */
}
#include "pack_struct_end.h"
typedef struct xNBNSAnswer NBNSAnswer_t;
/**
* @brief Utility function to cast pointer of a type to pointer of type NBNSAnswer_t.
*
* @return The casted pointer.
*/
static portINLINE ipDECL_CAST_PTR_FUNC_FOR_TYPE( NBNSAnswer_t )
{
return ( NBNSAnswer_t * ) pvArgument;
}
#endif /* ipconfigUSE_NBNS == 1 */
/*-----------------------------------------------------------*/
#if ( ipconfigUSE_DNS_CACHE == 1 )
uint32_t FreeRTOS_dnslookup( const char * pcHostName )
{
uint32_t ulIPAddress = 0UL;
( void ) prvProcessDNSCache( pcHostName, &ulIPAddress, 0, pdTRUE );
return ulIPAddress;
}
#endif /* ipconfigUSE_DNS_CACHE == 1 */
/*-----------------------------------------------------------*/
#if ( ipconfigDNS_USE_CALLBACKS == 1 )
/** @brief The structure to hold information for a DNS callback. */
typedef struct xDNS_Callback
{
TickType_t uxRemaningTime; /**< Timeout in ms */
FOnDNSEvent pCallbackFunction; /**< Function to be called when the address has been found or when a timeout has been reached */
TimeOut_t uxTimeoutState; /**< Timeout state. */
void * pvSearchID; /**< Search ID of the callback function. */
struct xLIST_ITEM xListItem; /**< List struct. */
char pcName[ 1 ]; /**< 1 character name. */
} DNSCallback_t;
/**
* @brief Utility function to cast pointer of a type to pointer of type DNSCallback_t.
*
* @return The casted pointer.
*/
static portINLINE ipDECL_CAST_PTR_FUNC_FOR_TYPE( DNSCallback_t )
{
return ( DNSCallback_t * ) pvArgument;
}
/** @brief The list of all callback structures. */
static List_t xCallbackList;
/**
* @brief Define FreeRTOS_gethostbyname() as a normal blocking call.
*
* @param[in] pcHostName: The hostname whose IP address is being searched for.
*
* @return The IP-address of the hostname.
*/
uint32_t FreeRTOS_gethostbyname( const char * pcHostName )
{
return FreeRTOS_gethostbyname_a( pcHostName, NULL, ( void * ) NULL, 0U );
}
/*-----------------------------------------------------------*/
/** @brief Initialise the list of call-back structures.
*/
void vDNSInitialise( void )
{
vListInitialise( &xCallbackList );
}
/*-----------------------------------------------------------*/
/**
* @brief Iterate through the list of call-back structures and remove
* old entries which have reached a timeout.
* As soon as the list has become empty, the DNS timer will be stopped.
* In case pvSearchID is supplied, the user wants to cancel a DNS request.
*
* @param[in] pvSearchID: The search ID of callback function whose associated
* DNS request is being cancelled. If non-ID specific checking of
* all requests is required, then this field should be kept as NULL.
*/
void vDNSCheckCallBack( void * pvSearchID )
{
const ListItem_t * pxIterator;
const ListItem_t * xEnd = listGET_END_MARKER( &xCallbackList );
vTaskSuspendAll();
{
for( pxIterator = ( const ListItem_t * ) listGET_NEXT( xEnd );
pxIterator != xEnd;
)
{
DNSCallback_t * pxCallback = ipCAST_PTR_TO_TYPE_PTR( DNSCallback_t, listGET_LIST_ITEM_OWNER( pxIterator ) );
/* Move to the next item because we might remove this item */
pxIterator = ( const ListItem_t * ) listGET_NEXT( pxIterator );
if( ( pvSearchID != NULL ) && ( pvSearchID == pxCallback->pvSearchID ) )
{
( void ) uxListRemove( &( pxCallback->xListItem ) );
vPortFree( pxCallback );
}
else if( xTaskCheckForTimeOut( &pxCallback->uxTimeoutState, &pxCallback->uxRemaningTime ) != pdFALSE )
{
pxCallback->pCallbackFunction( pxCallback->pcName, pxCallback->pvSearchID, 0 );
( void ) uxListRemove( &( pxCallback->xListItem ) );
vPortFree( pxCallback );
}
else
{
/* This call-back is still waiting for a reply or a time-out. */
}
}
}
( void ) xTaskResumeAll();
if( listLIST_IS_EMPTY( &xCallbackList ) != pdFALSE )
{
vIPSetDnsTimerEnableState( pdFALSE );
}
}
/*-----------------------------------------------------------*/
/**
* @brief Remove the entry defined by the search ID to cancel a DNS request.
*
* @param[in] pvSearchID: The search ID of the callback function associated with
* the DNS request being cancelled. Note that the value of
* the pointer matters, not the pointee.
*/
void FreeRTOS_gethostbyname_cancel( void * pvSearchID )
{
/* _HT_ Should better become a new API call to have the IP-task remove the callback */
vDNSCheckCallBack( pvSearchID );
}
/*-----------------------------------------------------------*/
/**
* @brief FreeRTOS_gethostbyname_a() was called along with callback parameters.
* Store them in a list for later reference.
*
* @param[in] pcHostName: The hostname whose IP address is being searched for.
* @param[in] pvSearchID: The search ID of the DNS callback function to set.
* @param[in] pCallbackFunction: The callback function pointer.
* @param[in] uxTimeout: Timeout of the callback function.
* @param[in] uxIdentifier: Random number used as ID in the DNS message.
*/
static void vDNSSetCallBack( const char * pcHostName,
void * pvSearchID,
FOnDNSEvent pCallbackFunction,
TickType_t uxTimeout,
TickType_t uxIdentifier )
{
size_t lLength = strlen( pcHostName );
DNSCallback_t * pxCallback = ipCAST_PTR_TO_TYPE_PTR( DNSCallback_t, pvPortMalloc( sizeof( *pxCallback ) + lLength ) );
/* Translate from ms to number of clock ticks. */
uxTimeout /= portTICK_PERIOD_MS;
if( pxCallback != NULL )
{
if( listLIST_IS_EMPTY( &xCallbackList ) != pdFALSE )
{
/* This is the first one, start the DNS timer to check for timeouts */
vIPReloadDNSTimer( FreeRTOS_min_uint32( 1000U, uxTimeout ) );
}
( void ) strcpy( pxCallback->pcName, pcHostName );
pxCallback->pCallbackFunction = pCallbackFunction;
pxCallback->pvSearchID = pvSearchID;
pxCallback->uxRemaningTime = uxTimeout;
vTaskSetTimeOutState( &pxCallback->uxTimeoutState );
listSET_LIST_ITEM_OWNER( &( pxCallback->xListItem ), ( void * ) pxCallback );
listSET_LIST_ITEM_VALUE( &( pxCallback->xListItem ), uxIdentifier );
vTaskSuspendAll();
{
vListInsertEnd( &xCallbackList, &pxCallback->xListItem );
}
( void ) xTaskResumeAll();
}
}
/*-----------------------------------------------------------*/
/**
* @brief A DNS reply was received, see if there is any matching entry and
* call the handler.
*
* @param[in] uxIdentifier: Identifier associated with the callback function.
* @param[in] pcName: The name associated with the callback function.
* @param[in] ulIPAddress: IP-address obtained from the DNS server.
*
* @return Returns pdTRUE if uxIdentifier was recognized.
*/
static BaseType_t xDNSDoCallback( TickType_t uxIdentifier,
const char * pcName,
uint32_t ulIPAddress )
{
BaseType_t xResult = pdFALSE;
const ListItem_t * pxIterator;
const ListItem_t * xEnd = listGET_END_MARKER( &xCallbackList );
vTaskSuspendAll();
{
for( pxIterator = ( const ListItem_t * ) listGET_NEXT( xEnd );
pxIterator != ( const ListItem_t * ) xEnd;
pxIterator = ( const ListItem_t * ) listGET_NEXT( pxIterator ) )
{
if( listGET_LIST_ITEM_VALUE( pxIterator ) == uxIdentifier )
{
DNSCallback_t * pxCallback = ipCAST_PTR_TO_TYPE_PTR( DNSCallback_t, listGET_LIST_ITEM_OWNER( pxIterator ) );
pxCallback->pCallbackFunction( pcName, pxCallback->pvSearchID, ulIPAddress );
( void ) uxListRemove( &pxCallback->xListItem );
vPortFree( pxCallback );
if( listLIST_IS_EMPTY( &xCallbackList ) != pdFALSE )
{
/* The list of outstanding requests is empty. No need for periodic polling. */
vIPSetDnsTimerEnableState( pdFALSE );
}
xResult = pdTRUE;
break;
}
}
}
( void ) xTaskResumeAll();
return xResult;
}
#endif /* ipconfigDNS_USE_CALLBACKS == 1 */
/*-----------------------------------------------------------*/
#if ( ipconfigDNS_USE_CALLBACKS == 0 )
/**
* @brief Get the IP-address corresponding to the given hostname.
*
* @param[in] pcHostName: The hostname whose IP address is being queried.
*
* @return The IP-address corresponding to the hostname.
*/
uint32_t FreeRTOS_gethostbyname( const char * pcHostName )
{
return prvPrepareLookup( pcHostName );
}
#else
/**
* @brief Get the IP-address corresponding to the given hostname.
*
* @param[in] pcHostName: The hostname whose IP address is being queried.
* @param[in] pCallback: The callback function which will be called upon DNS response.
* @param[in] pvSearchID: Search ID for the callback function.
* @param[in] uxTimeout: Timeout for the callback function.
*
* @return The IP-address corresponding to the hostname.
*/
uint32_t FreeRTOS_gethostbyname_a( const char * pcHostName,
FOnDNSEvent pCallback,
void * pvSearchID,
TickType_t uxTimeout )
{
return prvPrepareLookup( pcHostName, pCallback, pvSearchID, uxTimeout );
}
#endif /* if ( ipconfigDNS_USE_CALLBACKS == 0 ) */
#if ( ipconfigDNS_USE_CALLBACKS == 1 )
/**
* @brief Check if hostname is already known. If not, call prvGetHostByName() to send a DNS request.
*
* @param[in] pcHostName: The hostname whose IP address is being queried.
* @param[in] pCallback: The callback function which will be called upon DNS response.
* @param[in] pvSearchID: Search ID for the callback function.
* @param[in] uxTimeout: Timeout for the callback function.
*
* @return The IP-address corresponding to the hostname.
*/
static uint32_t prvPrepareLookup( const char * pcHostName,
FOnDNSEvent pCallback,
void * pvSearchID,
TickType_t uxTimeout )
#else
/**
* @brief Check if hostname is already known. If not, call prvGetHostByName() to send a DNS request.
*
* @param[in] pcHostName: The hostname whose IP address is being queried.
*
* @return The IP-address corresponding to the hostname.
*/
static uint32_t prvPrepareLookup( const char * pcHostName )
#endif
{
uint32_t ulIPAddress = 0UL;
TickType_t uxReadTimeOut_ticks = ipconfigDNS_RECEIVE_BLOCK_TIME_TICKS;
/* Generate a unique identifier for this query. Keep it in a local variable
* as gethostbyname() may be called from different threads */
BaseType_t xHasRandom = pdFALSE;
TickType_t uxIdentifier = 0U;
#if ( ipconfigUSE_DNS_CACHE != 0 )
BaseType_t xLengthOk = pdFALSE;
#endif
#if ( ipconfigUSE_DNS_CACHE != 0 )
{
if( pcHostName != NULL )
{
size_t xLength = strlen( pcHostName ) + 1U;
if( xLength <= ipconfigDNS_CACHE_NAME_LENGTH )
{
/* The name is not too long. */
xLengthOk = pdTRUE;
}
else
{
FreeRTOS_printf( ( "prvPrepareLookup: name is too long ( %lu > %lu )\n",
( uint32_t ) xLength,
( uint32_t ) ipconfigDNS_CACHE_NAME_LENGTH ) );
}
}
}
if( ( pcHostName != NULL ) && ( xLengthOk != pdFALSE ) )
#else /* if ( ipconfigUSE_DNS_CACHE != 0 ) */
if( pcHostName != NULL )
#endif /* ( ipconfigUSE_DNS_CACHE != 0 ) */
{
/* If the supplied hostname is IP address, convert it to uint32_t
* and return. */
#if ( ipconfigINCLUDE_FULL_INET_ADDR == 1 )
{
ulIPAddress = FreeRTOS_inet_addr( pcHostName );
}
#endif /* ipconfigINCLUDE_FULL_INET_ADDR == 1 */
/* If a DNS cache is used then check the cache before issuing another DNS
* request. */
#if ( ipconfigUSE_DNS_CACHE == 1 )
{
if( ulIPAddress == 0UL )
{
ulIPAddress = FreeRTOS_dnslookup( pcHostName );
if( ulIPAddress != 0UL )
{
FreeRTOS_debug_printf( ( "FreeRTOS_gethostbyname: found '%s' in cache: %lxip\n", pcHostName, ulIPAddress ) );
}
else
{
/* prvGetHostByName will be called to start a DNS lookup. */
}
}
}
#endif /* ipconfigUSE_DNS_CACHE == 1 */
/* Generate a unique identifier. */
if( ulIPAddress == 0UL )
{
uint32_t ulNumber;
xHasRandom = xApplicationGetRandomNumber( &( ulNumber ) );
/* DNS identifiers are 16-bit. */
uxIdentifier = ( TickType_t ) ( ulNumber & 0xffffU );
}
#if ( ipconfigDNS_USE_CALLBACKS == 1 )
{
if( pCallback != NULL )
{
if( ulIPAddress == 0UL )
{
/* The user has provided a callback function, so do not block on recvfrom() */
if( xHasRandom != pdFALSE )
{
uxReadTimeOut_ticks = 0U;
vDNSSetCallBack( pcHostName, pvSearchID, pCallback, uxTimeout, uxIdentifier );
}
}
else
{
/* The IP address is known, do the call-back now. */
pCallback( pcHostName, pvSearchID, ulIPAddress );
}
}
}
#endif /* if ( ipconfigDNS_USE_CALLBACKS == 1 ) */
if( ( ulIPAddress == 0UL ) && ( xHasRandom != pdFALSE ) )
{
ulIPAddress = prvGetHostByName( pcHostName, uxIdentifier, uxReadTimeOut_ticks );
}
}
return ulIPAddress;
}
/*-----------------------------------------------------------*/
/**
* @brief Prepare and send a message to a DNS server. 'uxReadTimeOut_ticks' will be passed as
* zero, in case the user has supplied a call-back function.
*
* @param[in] pcHostName: The hostname for which an IP address is required.
* @param[in] uxIdentifier: Identifier to send in the DNS message.
* @param[in] uxReadTimeOut_ticks: The timeout in ticks for waiting. In case the user has supplied
* a call-back function, this value should be zero.
*
* @return The IPv4 IP address for the hostname being queried. It will be zero if there is no reply.
*/
static uint32_t prvGetHostByName( const char * pcHostName,
TickType_t uxIdentifier,
TickType_t uxReadTimeOut_ticks )
{
struct freertos_sockaddr xAddress;
Socket_t xDNSSocket;
uint32_t ulIPAddress = 0UL;
uint32_t ulAddressLength = sizeof( struct freertos_sockaddr );
BaseType_t xAttempt;
int32_t lBytes;
size_t uxPayloadLength, uxExpectedPayloadLength;
TickType_t uxWriteTimeOut_ticks = ipconfigDNS_SEND_BLOCK_TIME_TICKS;
#if ( ipconfigUSE_LLMNR == 1 )
BaseType_t bHasDot = pdFALSE;
#endif /* ipconfigUSE_LLMNR == 1 */
/* If LLMNR is being used then determine if the host name includes a '.' -
* if not then LLMNR can be used as the lookup method. */
#if ( ipconfigUSE_LLMNR == 1 )
{
const char * pucPtr;
for( pucPtr = pcHostName; *pucPtr != ( char ) 0; pucPtr++ )
{
if( *pucPtr == '.' )
{
bHasDot = pdTRUE;
break;
}
}
}
#endif /* ipconfigUSE_LLMNR == 1 */
/* Two is added at the end for the count of characters in the first
* subdomain part and the string end byte. */
uxExpectedPayloadLength = sizeof( DNSMessage_t ) + strlen( pcHostName ) + sizeof( uint16_t ) + sizeof( uint16_t ) + 2U;
xDNSSocket = prvCreateDNSSocket();
if( xDNSSocket != NULL )
{
/* Ideally we should check for the return value. But since we are passing
* correct parameters, and xDNSSocket is != NULL, the return value is
* going to be '0' i.e. success. Thus, return value is discarded */
( void ) FreeRTOS_setsockopt( xDNSSocket, 0, FREERTOS_SO_SNDTIMEO, &( uxWriteTimeOut_ticks ), sizeof( TickType_t ) );
( void ) FreeRTOS_setsockopt( xDNSSocket, 0, FREERTOS_SO_RCVTIMEO, &( uxReadTimeOut_ticks ), sizeof( TickType_t ) );
for( xAttempt = 0; xAttempt < ipconfigDNS_REQUEST_ATTEMPTS; xAttempt++ )
{
size_t uxHeaderBytes;
NetworkBufferDescriptor_t * pxNetworkBuffer;
uint8_t * pucUDPPayloadBuffer = NULL, * pucReceiveBuffer;
/* Get a buffer. This uses a maximum delay, but the delay will be
* capped to ipconfigUDP_MAX_SEND_BLOCK_TIME_TICKS so the return value
* still needs to be tested. */
uxHeaderBytes = ipSIZE_OF_ETH_HEADER + ipSIZE_OF_IPv4_HEADER + ipSIZE_OF_UDP_HEADER;
pxNetworkBuffer = pxGetNetworkBufferWithDescriptor( uxHeaderBytes + uxExpectedPayloadLength, 0UL );
if( pxNetworkBuffer != NULL )
{
pucUDPPayloadBuffer = &( pxNetworkBuffer->pucEthernetBuffer[ uxHeaderBytes ] );
}
if( pucUDPPayloadBuffer != NULL )
{
/* Create the message in the obtained buffer. */
uxPayloadLength = prvCreateDNSMessage( pucUDPPayloadBuffer, pcHostName, uxIdentifier );
iptraceSENDING_DNS_REQUEST();
/* Obtain the DNS server address. */
FreeRTOS_GetAddressConfiguration( NULL, NULL, NULL, &ulIPAddress );
/* Send the DNS message. */
#if ( ipconfigUSE_LLMNR == 1 )
if( bHasDot == pdFALSE )
{
/* Use LLMNR addressing. */
( ipCAST_PTR_TO_TYPE_PTR( DNSMessage_t, pucUDPPayloadBuffer ) )->usFlags = 0;
xAddress.sin_addr = ipLLMNR_IP_ADDR; /* Is in network byte order. */
xAddress.sin_port = ipLLMNR_PORT;
xAddress.sin_port = FreeRTOS_ntohs( xAddress.sin_port );
}
else
#endif
{
/* Use DNS server. */
xAddress.sin_addr = ulIPAddress;
xAddress.sin_port = dnsDNS_PORT;
}
ulIPAddress = 0UL;
if( FreeRTOS_sendto( xDNSSocket, pucUDPPayloadBuffer, uxPayloadLength, FREERTOS_ZERO_COPY, &xAddress, sizeof( xAddress ) ) != 0 )
{
/* Wait for the reply. */
lBytes = FreeRTOS_recvfrom( xDNSSocket, &pucReceiveBuffer, 0, FREERTOS_ZERO_COPY, &xAddress, &ulAddressLength );
if( lBytes > 0 )
{
BaseType_t xExpected;
const DNSMessage_t * pxDNSMessageHeader = ipCAST_CONST_PTR_TO_CONST_TYPE_PTR( DNSMessage_t, pucReceiveBuffer );
/* See if the identifiers match. */
if( uxIdentifier == ( TickType_t ) pxDNSMessageHeader->usIdentifier )
{
xExpected = pdTRUE;
}
else
{
/* The reply was not expected. */
xExpected = pdFALSE;
}
/* The reply was received. Process it. */
#if ( ipconfigDNS_USE_CALLBACKS == 0 )
/* It is useless to analyse the unexpected reply
* unless asynchronous look-ups are enabled. */
if( xExpected != pdFALSE )
#endif /* ipconfigDNS_USE_CALLBACKS == 0 */
{
ulIPAddress = prvParseDNSReply( pucReceiveBuffer, ( size_t ) lBytes, xExpected );
}
/* Finished with the buffer. The zero copy interface
* is being used, so the buffer must be freed by the
* task. */
FreeRTOS_ReleaseUDPPayloadBuffer( pucReceiveBuffer );
if( ulIPAddress != 0UL )
{
/* All done. */
/* coverity[break_stmt] : Break statement terminating the loop */
break;
}
}
}
else
{
/* The message was not sent so the stack will not be
* releasing the zero copy - it must be released here. */
vReleaseNetworkBufferAndDescriptor( pxNetworkBuffer );
}
}
if( uxReadTimeOut_ticks == 0U )
{
/* This DNS lookup is asynchronous, using a call-back:
* send the request only once. */
break;
}
}
/* Finished with the socket. */
( void ) FreeRTOS_closesocket( xDNSSocket );
}
return ulIPAddress;
}
/*-----------------------------------------------------------*/
/**
* @brief Create the DNS message in the zero copy buffer passed in the first parameter.
*
* @param[in,out] pucUDPPayloadBuffer: The zero copy buffer where the DNS message will be created.
* @param[in] pcHostName: Hostname to be looked up.
* @param[in] uxIdentifier: The identifier to be added to the DNS message.
*
* @return Total size of the generated message, which is the space from the last written byte
* to the beginning of the buffer.
*/
_static size_t prvCreateDNSMessage( uint8_t * pucUDPPayloadBuffer,
const char * pcHostName,
TickType_t uxIdentifier )
{
DNSMessage_t * pxDNSMessageHeader;
size_t uxStart, uxIndex;
DNSTail_t const * pxTail;
static const DNSMessage_t xDefaultPartDNSHeader =
{
0, /* The identifier will be overwritten. */
dnsOUTGOING_FLAGS, /* Flags set for standard query. */
dnsONE_QUESTION, /* One question is being asked. */
0, /* No replies are included. */
0, /* No authorities. */
0 /* No additional authorities. */
};
/* memcpy() helper variables for MISRA Rule 21.15 compliance*/
const void * pvCopySource;
void * pvCopyDest;
/* Copy in the const part of the header. Intentionally using different
* pointers with memcpy() to put the information in to correct place. */
/*
* Use helper variables for memcpy() to remain
* compliant with MISRA Rule 21.15. These should be
* optimized away.
*/
pvCopySource = &xDefaultPartDNSHeader;
pvCopyDest = pucUDPPayloadBuffer;
( void ) memcpy( pvCopyDest, pvCopySource, sizeof( xDefaultPartDNSHeader ) );
/* Write in a unique identifier. Cast the Payload Buffer to DNSMessage_t
* to easily access fields of the DNS Message. */
pxDNSMessageHeader = ipCAST_PTR_TO_TYPE_PTR( DNSMessage_t, pucUDPPayloadBuffer );
pxDNSMessageHeader->usIdentifier = ( uint16_t ) uxIdentifier;
/* Create the resource record at the end of the header. First
* find the end of the header. */
uxStart = sizeof( xDefaultPartDNSHeader );
/* Leave a gap for the first length byte. */
uxIndex = uxStart + 1U;
/* Copy in the host name. */
( void ) strcpy( ( char * ) &( pucUDPPayloadBuffer[ uxIndex ] ), pcHostName );
/* Walk through the string to replace the '.' characters with byte
* counts. pucStart holds the address of the byte count. Walking the
* string starts after the byte count position. */
uxIndex = uxStart;
do
{
size_t uxLength;
/* Skip the length byte. */
uxIndex++;
while( ( pucUDPPayloadBuffer[ uxIndex ] != ( uint8_t ) 0U ) &&
( pucUDPPayloadBuffer[ uxIndex ] != ( uint8_t ) ASCII_BASELINE_DOT ) )
{
uxIndex++;
}
/* Fill in the byte count, then move the pucStart pointer up to
* the found byte position. */
uxLength = uxIndex - ( uxStart + 1U );
pucUDPPayloadBuffer[ uxStart ] = ( uint8_t ) uxLength;
uxStart = uxIndex;
} while( pucUDPPayloadBuffer[ uxIndex ] != ( uint8_t ) 0U );
/* Finish off the record. Cast the record onto DNSTail_t structure to easily
* access the fields of the DNS Message. */
pxTail = ipCAST_PTR_TO_TYPE_PTR( DNSTail_t, &( pucUDPPayloadBuffer[ uxStart + 1U ] ) );
#if defined( _lint ) || defined( __COVERITY__ )
( void ) pxTail;
#else
vSetField16( pxTail, DNSTail_t, usType, dnsTYPE_A_HOST );
vSetField16( pxTail, DNSTail_t, usClass, dnsCLASS_IN );
#endif
/* Return the total size of the generated message, which is the space from
* the last written byte to the beginning of the buffer. */
return uxIndex + sizeof( DNSTail_t ) + 1U;
}
/*-----------------------------------------------------------*/
#if ( ipconfigUSE_DNS_CACHE == 1 ) || ( ipconfigDNS_USE_CALLBACKS == 1 )
/**
* @brief Read the Name field out of a DNS response packet.
*
* @param[in] pucByte: Pointer to the DNS response.
* @param[in] uxRemainingBytes: Length of the DNS response.
* @param[out] pcName: The pointer in which the name in the DNS response will be returned.
* @param[in] uxDestLen: Size of the pcName array.
*
* @return If a fully formed name was found, then return the number of bytes processed in pucByte.
*/
_static size_t prvReadNameField( const uint8_t * pucByte,
size_t uxRemainingBytes,
char * pcName,
size_t uxDestLen )
{
size_t uxNameLen = 0U;
size_t uxIndex = 0U;
size_t uxSourceLen = uxRemainingBytes;
/* uxCount gets the values from pucByte and counts down to 0.
* No need to have a different type than that of pucByte */
size_t uxCount;
if( uxSourceLen == ( size_t ) 0U )
{
/* Return 0 value in case of error. */
uxIndex = 0U;
}
/* Determine if the name is the fully coded name, or an offset to the name
* elsewhere in the message. */
else if( ( pucByte[ uxIndex ] & dnsNAME_IS_OFFSET ) == dnsNAME_IS_OFFSET )
{
/* Jump over the two byte offset. */
if( uxSourceLen > sizeof( uint16_t ) )
{
uxIndex += sizeof( uint16_t );
}
else
{
uxIndex = 0U;
}
}
else
{
/* 'uxIndex' points to the full name. Walk over the string. */
while( ( uxIndex < uxSourceLen ) && ( pucByte[ uxIndex ] != ( uint8_t ) 0x00U ) )
{
/* If this is not the first time through the loop, then add a
* separator in the output. */
if( ( uxNameLen > 0U ) )
{
if( uxNameLen >= uxDestLen )
{
uxIndex = 0U;
/* coverity[break_stmt] : Break statement terminating the loop */
break;
}
pcName[ uxNameLen ] = '.';
uxNameLen++;
}
/* Process the first/next sub-string. */
uxCount = ( size_t ) pucByte[ uxIndex ];
uxIndex++;
if( ( uxIndex + uxCount ) > uxSourceLen )
{
uxIndex = 0U;
break;
}
while( ( uxCount-- != 0U ) && ( uxIndex < uxSourceLen ) )
{
if( uxNameLen >= uxDestLen )
{
uxIndex = 0U;
break;
/* break out of inner loop here
* break out of outer loop at the test uxNameLen >= uxDestLen. */
}
pcName[ uxNameLen ] = ( char ) pucByte[ uxIndex ];
uxNameLen++;
uxIndex++;
}
}
/* Confirm that a fully formed name was found. */
if( uxIndex > 0U )
{
if( ( uxNameLen < uxDestLen ) && ( uxIndex < uxSourceLen ) && ( pucByte[ uxIndex ] == 0U ) )
{
pcName[ uxNameLen ] = '\0';
uxIndex++;
}
else
{
uxIndex = 0U;
}
}
}
return uxIndex;
}
#endif /* ipconfigUSE_DNS_CACHE || ipconfigDNS_USE_CALLBACKS */
/*-----------------------------------------------------------*/
/**
* @brief Simple routine that jumps over the NAME field of a resource record.
*
* @param[in] pucByte: The pointer to the resource record.
* @param[in] uxLength: Length of the resource record.
*
* @return It returns the number of bytes read, or zero when an error has occurred.
*/
_static size_t prvSkipNameField( const uint8_t * pucByte,
size_t uxLength )
{
size_t uxChunkLength;
size_t uxSourceLenCpy = uxLength;
size_t uxIndex = 0U;
if( uxSourceLenCpy == 0U )
{
uxIndex = 0U;
}
/* Determine if the name is the fully coded name, or an offset to the name
* elsewhere in the message. */
else if( ( pucByte[ uxIndex ] & dnsNAME_IS_OFFSET ) == dnsNAME_IS_OFFSET )
{
/* Jump over the two byte offset. */
if( uxSourceLenCpy > sizeof( uint16_t ) )
{
uxIndex += sizeof( uint16_t );
}
else
{
uxIndex = 0U;
}
}
else
{
/* pucByte points to the full name. Walk over the string. */
while( ( pucByte[ uxIndex ] != 0U ) && ( uxSourceLenCpy > 1U ) )
{
/* Conversion to size_t causes addition to be done
* in size_t */
uxChunkLength = ( ( size_t ) pucByte[ uxIndex ] ) + 1U;
if( uxSourceLenCpy > uxChunkLength )
{
uxSourceLenCpy -= uxChunkLength;
uxIndex += uxChunkLength;
}
else
{
uxIndex = 0U;
break;
}
}
/* Confirm that a fully formed name was found. */
if( uxIndex > 0U )
{
if( pucByte[ uxIndex ] == 0U )
{
uxIndex++;
}
else
{
uxIndex = 0U;
}
}
}
return uxIndex;
}
/*-----------------------------------------------------------*/
/* The function below will only be called :
* when ipconfigDNS_USE_CALLBACKS == 1
* when ipconfigUSE_LLMNR == 1
* for testing purposes, by the module test_freertos_tcp.c
*/
/**
* @brief Perform some preliminary checks and then parse the DNS packet.
*
* @param[in] pxNetworkBuffer: The network buffer to be parsed.
*
* @return Always pdFAIL to indicate that the packet was not consumed and must
* be released by the caller.
*/
uint32_t ulDNSHandlePacket( const NetworkBufferDescriptor_t * pxNetworkBuffer )
{
uint8_t * pucPayLoadBuffer;
size_t uxPayloadSize;
/* Only proceed if the payload length indicated in the header
* appears to be valid. */
if( pxNetworkBuffer->xDataLength >= sizeof( UDPPacket_t ) )
{
uxPayloadSize = pxNetworkBuffer->xDataLength - sizeof( UDPPacket_t );
if( uxPayloadSize >= sizeof( DNSMessage_t ) )
{
pucPayLoadBuffer = &( pxNetworkBuffer->pucEthernetBuffer[ sizeof( UDPPacket_t ) ] );
/* The parameter pdFALSE indicates that the reply was not expected. */
( void ) prvParseDNSReply( pucPayLoadBuffer,
uxPayloadSize,
pdFALSE );
}
}
/* The packet was not consumed. */
return pdFAIL;
}
/*-----------------------------------------------------------*/
#if ( ipconfigUSE_NBNS == 1 )
/**
* @brief Handle an NBNS packet.
*
* @param[in] pxNetworkBuffer: The network buffer holding the NBNS packet.
*
* @return pdFAIL to show that the packet was not consumed.
*/
uint32_t ulNBNSHandlePacket( NetworkBufferDescriptor_t * pxNetworkBuffer )
{
UDPPacket_t * pxUDPPacket = ipCAST_PTR_TO_TYPE_PTR( UDPPacket_t, pxNetworkBuffer->pucEthernetBuffer );
uint8_t * pucUDPPayloadBuffer = &( pxNetworkBuffer->pucEthernetBuffer[ sizeof( *pxUDPPacket ) ] );
prvTreatNBNS( pucUDPPayloadBuffer,
pxNetworkBuffer->xDataLength,
pxUDPPacket->xIPHeader.ulSourceIPAddress );
/* The packet was not consumed. */
return pdFAIL;
}
#endif /* ipconfigUSE_NBNS */
/*-----------------------------------------------------------*/
/**
* @brief Process a response packet from a DNS server, or an LLMNR reply.
*
* @param[in] pucUDPPayloadBuffer: The DNS response received as a UDP
* payload.
* @param[in] uxBufferLength: Length of the UDP payload buffer.
* @param[in] xExpected: indicates whether the identifier in the reply
* was expected, and thus if the DNS cache may be
* updated with the reply.
*
* @return The IP address in the DNS response if present and if xExpected is set to pdTRUE.
* An error code (dnsPARSE_ERROR) if there was an error in the DNS response.
* 0 if xExpected set to pdFALSE.
*/
_static uint32_t prvParseDNSReply( uint8_t * pucUDPPayloadBuffer,
size_t uxBufferLength,
BaseType_t xExpected )
{
DNSMessage_t * pxDNSMessageHeader;
/* This pointer is not used to modify anything */
const DNSAnswerRecord_t * pxDNSAnswerRecord;
uint32_t ulIPAddress = 0UL;
#if ( ipconfigUSE_LLMNR == 1 )
char * pcRequestedName = NULL;
#endif
uint8_t * pucByte;
size_t uxSourceBytesRemaining;
uint16_t x, usDataLength, usQuestions;
uint16_t usType = 0U;
BaseType_t xReturn = pdTRUE;
/* memcpy() helper variables for MISRA Rule 21.15 compliance*/
const void * pvCopySource;
void * pvCopyDest;
#if ( ipconfigUSE_LLMNR == 1 )
uint16_t usClass = 0U;
#endif
#if ( ipconfigUSE_DNS_CACHE == 1 ) || ( ipconfigDNS_USE_CALLBACKS == 1 )
BaseType_t xDoStore = xExpected;
char pcName[ ipconfigDNS_CACHE_NAME_LENGTH ] = "";
#endif
const size_t uxAddressLength = ipSIZE_OF_IPv4_ADDRESS;
/* Ensure that the buffer is of at least minimal DNS message length. */
if( uxBufferLength < sizeof( DNSMessage_t ) )
{
xReturn = pdFALSE;
}
else
{
uxSourceBytesRemaining = uxBufferLength;
/* Parse the DNS message header. Map the byte stream onto a structure
* for easier access. */
pxDNSMessageHeader = ipCAST_PTR_TO_TYPE_PTR( DNSMessage_t, pucUDPPayloadBuffer );
/* Introduce a do {} while (0) to allow the use of breaks. */
do
{
size_t uxBytesRead = 0U;
size_t uxResult;
/* Start at the first byte after the header. */
pucByte = &( pucUDPPayloadBuffer[ sizeof( DNSMessage_t ) ] );
uxSourceBytesRemaining -= sizeof( DNSMessage_t );
/* Skip any question records. */
usQuestions = FreeRTOS_ntohs( pxDNSMessageHeader->usQuestions );
for( x = 0U; x < usQuestions; x++ )
{
#if ( ipconfigUSE_LLMNR == 1 )
{
if( x == 0U )
{
pcRequestedName = ( char * ) pucByte;
}
}
#endif
#if ( ipconfigUSE_DNS_CACHE == 1 ) || ( ipconfigDNS_USE_CALLBACKS == 1 )
if( x == 0U )
{
uxResult = prvReadNameField( pucByte,
uxSourceBytesRemaining,
pcName,
sizeof( pcName ) );
/* Check for a malformed response. */
if( uxResult == 0U )
{
xReturn = pdFALSE;
break;
}
uxBytesRead += uxResult;
pucByte = &( pucByte[ uxResult ] );
uxSourceBytesRemaining -= uxResult;
}
else
#endif /* ipconfigUSE_DNS_CACHE || ipconfigDNS_USE_CALLBACKS */
{
/* Skip the variable length pcName field. */
uxResult = prvSkipNameField( pucByte,
uxSourceBytesRemaining );
/* Check for a malformed response. */
if( uxResult == 0U )
{
xReturn = pdFALSE;
break;
}
uxBytesRead += uxResult;
pucByte = &( pucByte[ uxResult ] );
uxSourceBytesRemaining -= uxResult;
}
/* Check the remaining buffer size. */
if( uxSourceBytesRemaining >= sizeof( uint32_t ) )
{
#if ( ipconfigUSE_LLMNR == 1 )
{
/* usChar2u16 returns value in host endianness. */
usType = usChar2u16( pucByte );
usClass = usChar2u16( &( pucByte[ 2 ] ) );
}
#endif /* ipconfigUSE_LLMNR */
/* Skip the type and class fields. */
pucByte = &( pucByte[ sizeof( uint32_t ) ] );
uxSourceBytesRemaining -= sizeof( uint32_t );
}
else
{
xReturn = pdFALSE;
break;
}
}
if( xReturn == pdFALSE )
{
/* No need to proceed. Break out of the do-while loop. */
break;
}
/* Search through the answer records. */
pxDNSMessageHeader->usAnswers = FreeRTOS_ntohs( pxDNSMessageHeader->usAnswers );
if( ( pxDNSMessageHeader->usFlags & dnsRX_FLAGS_MASK ) == dnsEXPECTED_RX_FLAGS )
{
const uint16_t usCount = ( uint16_t ) ipconfigDNS_CACHE_ADDRESSES_PER_ENTRY;
uint16_t usNumARecordsStored = 0;
for( x = 0U; x < pxDNSMessageHeader->usAnswers; x++ )
{
BaseType_t xDoAccept;
if( usNumARecordsStored >= usCount )
{
/* Only count ipconfigDNS_CACHE_ADDRESSES_PER_ENTRY number of records. */
break;
}
uxResult = prvSkipNameField( pucByte,
uxSourceBytesRemaining );
/* Check for a malformed response. */
if( uxResult == 0U )
{
xReturn = pdFALSE;
break;
}
uxBytesRead += uxResult;
pucByte = &( pucByte[ uxResult ] );
uxSourceBytesRemaining -= uxResult;
/* Is there enough data for an IPv4 A record answer and, if so,
* is this an A record? */
if( uxSourceBytesRemaining < sizeof( uint16_t ) )
{
xReturn = pdFALSE;
break;
}
usType = usChar2u16( pucByte );
if( usType == ( uint16_t ) dnsTYPE_A_HOST )
{
if( uxSourceBytesRemaining >= ( sizeof( DNSAnswerRecord_t ) + uxAddressLength ) )
{
xDoAccept = pdTRUE;
}
else
{
xDoAccept = pdFALSE;
}
}
else
{
/* Unknown host type. */
xDoAccept = pdFALSE;
}
if( xDoAccept != pdFALSE )
{
/* This is the required record type and is of sufficient size. */
/* Mapping pucByte to a DNSAnswerRecord allows easy access of the
* fields of the structure. */
pxDNSAnswerRecord = ipCAST_PTR_TO_TYPE_PTR( DNSAnswerRecord_t, pucByte );
/* Sanity check the data length of an IPv4 answer. */
if( FreeRTOS_ntohs( pxDNSAnswerRecord->usDataLength ) == ( uint16_t ) uxAddressLength )
{
/* Copy the IP address out of the record. Using different pointers
* to copy only the portion we want is intentional here. */
/*
* Use helper variables for memcpy() to remain
* compliant with MISRA Rule 21.15. These should be
* optimized away.
*/
pvCopySource = &pucByte[ sizeof( DNSAnswerRecord_t ) ];
pvCopyDest = &ulIPAddress;
( void ) memcpy( pvCopyDest, pvCopySource, uxAddressLength );
#if ( ipconfigDNS_USE_CALLBACKS == 1 )
{
/* See if any asynchronous call was made to FreeRTOS_gethostbyname_a() */
if( xDNSDoCallback( ( TickType_t ) pxDNSMessageHeader->usIdentifier, pcName, ulIPAddress ) != pdFALSE )
{
/* This device has requested this DNS look-up.
* The result may be stored in the DNS cache. */
xDoStore = pdTRUE;
}
}
#endif /* ipconfigDNS_USE_CALLBACKS == 1 */
#if ( ipconfigUSE_DNS_CACHE == 1 )
{
char cBuffer[ 16 ];
/* The reply will only be stored in the DNS cache when the
* request was issued by this device. */
if( xDoStore != pdFALSE )
{
( void ) prvProcessDNSCache( pcName, &ulIPAddress, pxDNSAnswerRecord->ulTTL, pdFALSE );
usNumARecordsStored++; /* Track # of A records stored */
}
( void ) FreeRTOS_inet_ntop( FREERTOS_AF_INET, ( const void * ) &( ulIPAddress ), cBuffer, sizeof( cBuffer ) );
/* Show what has happened. */
FreeRTOS_printf( ( "DNS[0x%04lX]: The answer to '%s' (%s) will%s be stored\n",
( UBaseType_t ) pxDNSMessageHeader->usIdentifier,
pcName,
cBuffer,
( xDoStore != 0 ) ? "" : " NOT" ) );
}
#endif /* ipconfigUSE_DNS_CACHE */
}
pucByte = &( pucByte[ sizeof( DNSAnswerRecord_t ) + uxAddressLength ] );
uxSourceBytesRemaining -= ( sizeof( DNSAnswerRecord_t ) + uxAddressLength );
}
else if( uxSourceBytesRemaining >= sizeof( DNSAnswerRecord_t ) )
{
/* It's not an A record, so skip it. Get the header location
* and then jump over the header. */
/* Cast the response to DNSAnswerRecord for easy access to fields of the DNS response. */
pxDNSAnswerRecord = ipCAST_PTR_TO_TYPE_PTR( DNSAnswerRecord_t, pucByte );
pucByte = &( pucByte[ sizeof( DNSAnswerRecord_t ) ] );
uxSourceBytesRemaining -= sizeof( DNSAnswerRecord_t );
/* Determine the length of the answer data from the header. */
usDataLength = FreeRTOS_ntohs( pxDNSAnswerRecord->usDataLength );
/* Jump over the answer. */
if( uxSourceBytesRemaining >= usDataLength )
{
pucByte = &( pucByte[ usDataLength ] );
uxSourceBytesRemaining -= usDataLength;
}
else
{
/* Malformed response. */
xReturn = pdFALSE;
break;
}
}
else
{
/* Do nothing */
}
}
}
#if ( ipconfigUSE_LLMNR == 1 )
else if( ( usQuestions != ( uint16_t ) 0U ) && ( usType == dnsTYPE_A_HOST ) && ( usClass == dnsCLASS_IN ) && ( pcRequestedName != NULL ) )
{
/* If this is not a reply to our DNS request, it might an LLMNR
* request. */
if( xApplicationDNSQueryHook( &( pcRequestedName[ 1 ] ) ) != pdFALSE )
{
int16_t usLength;
NetworkBufferDescriptor_t * pxNewBuffer = NULL;
NetworkBufferDescriptor_t * pxNetworkBuffer = pxUDPPayloadBuffer_to_NetworkBuffer( pucUDPPayloadBuffer );
LLMNRAnswer_t * pxAnswer;
uint8_t * pucNewBuffer = NULL;
if( ( xBufferAllocFixedSize == pdFALSE ) && ( pxNetworkBuffer != NULL ) )
{
size_t uxDataLength = uxBufferLength + sizeof( UDPHeader_t ) + sizeof( EthernetHeader_t ) + sizeof( IPHeader_t );
/* Set the size of the outgoing packet. */
pxNetworkBuffer->xDataLength = uxDataLength;
pxNewBuffer = pxDuplicateNetworkBufferWithDescriptor( pxNetworkBuffer, uxDataLength + sizeof( LLMNRAnswer_t ) );
if( pxNewBuffer != NULL )
{
BaseType_t xOffset1, xOffset2;
xOffset1 = ( BaseType_t ) ( pucByte - pucUDPPayloadBuffer );
xOffset2 = ( BaseType_t ) ( ( ( uint8_t * ) pcRequestedName ) - pucUDPPayloadBuffer );
pxNetworkBuffer = pxNewBuffer;
pucNewBuffer = &( pxNetworkBuffer->pucEthernetBuffer[ ipUDP_PAYLOAD_OFFSET_IPv4 ] );
pucByte = &( pucNewBuffer[ xOffset1 ] );
pcRequestedName = ( char * ) &( pucNewBuffer[ xOffset2 ] );
pxDNSMessageHeader = ipCAST_PTR_TO_TYPE_PTR( DNSMessage_t, pucNewBuffer );
}
else
{
/* Just to indicate that the message may not be answered. */
pxNetworkBuffer = NULL;
}
}
/* The test on 'pucNewBuffer' is only to satisfy lint. */
if( ( pxNetworkBuffer != NULL ) && ( pucNewBuffer != NULL ) )
{
pxAnswer = ipCAST_PTR_TO_TYPE_PTR( LLMNRAnswer_t, pucByte );
/* We leave 'usIdentifier' and 'usQuestions' untouched */
#ifndef _lint
vSetField16( pxDNSMessageHeader, DNSMessage_t, usFlags, dnsLLMNR_FLAGS_IS_REPONSE ); /* Set the response flag */
vSetField16( pxDNSMessageHeader, DNSMessage_t, usAnswers, 1 ); /* Provide a single answer */
vSetField16( pxDNSMessageHeader, DNSMessage_t, usAuthorityRRs, 0 ); /* No authority */
vSetField16( pxDNSMessageHeader, DNSMessage_t, usAdditionalRRs, 0 ); /* No additional info */
#endif /* lint */
pxAnswer->ucNameCode = dnsNAME_IS_OFFSET;
pxAnswer->ucNameOffset = ( uint8_t ) ( pcRequestedName - ( char * ) pucNewBuffer );
#ifndef _lint
vSetField16( pxAnswer, LLMNRAnswer_t, usType, dnsTYPE_A_HOST ); /* Type A: host */
vSetField16( pxAnswer, LLMNRAnswer_t, usClass, dnsCLASS_IN ); /* 1: Class IN */
vSetField32( pxAnswer, LLMNRAnswer_t, ulTTL, dnsLLMNR_TTL_VALUE );
vSetField16( pxAnswer, LLMNRAnswer_t, usDataLength, 4 );
vSetField32( pxAnswer, LLMNRAnswer_t, ulIPAddress, FreeRTOS_ntohl( *ipLOCAL_IP_ADDRESS_POINTER ) );
#endif /* lint */
usLength = ( int16_t ) ( sizeof( *pxAnswer ) + ( size_t ) ( pucByte - pucNewBuffer ) );
prvReplyDNSMessage( pxNetworkBuffer, usLength );
if( pxNewBuffer != NULL )
{
vReleaseNetworkBufferAndDescriptor( pxNewBuffer );
}
}
}
}
else
{
/* Not an expected reply. */
}
#endif /* ipconfigUSE_LLMNR == 1 */
( void ) uxBytesRead;
} while( ipFALSE_BOOL );
}
if( xReturn == pdFALSE )
{
/* There was an error while parsing the DNS response. Return error code. */
ulIPAddress = dnsPARSE_ERROR;
}
else if( xExpected == pdFALSE )
{
/* Do not return a valid IP-address in case the reply was not expected. */
ulIPAddress = 0UL;
}
else
{
/* The IP-address found will be returned. */
}
#if ( ipconfigUSE_DNS_CACHE == 1 ) || ( ipconfigDNS_USE_CALLBACKS == 1 )
( void ) xDoStore;
#endif
return ulIPAddress;
}
/*-----------------------------------------------------------*/
#if ( ipconfigUSE_NBNS == 1 )
/**
* @brief Respond to an NBNS query or an NBNS reply.
*
* @param[in] pucPayload: the UDP payload of the NBNS message.
* @param[in] uxBufferLength: Length of the Buffer.
* @param[in] ulIPAddress: IP address of the sender.
*/
static void prvTreatNBNS( uint8_t * pucPayload,
size_t uxBufferLength,
uint32_t ulIPAddress )
{
uint16_t usFlags, usType, usClass;
uint8_t * pucSource, * pucTarget;
uint8_t ucByte;
uint8_t ucNBNSName[ 17 ];
uint8_t * pucUDPPayloadBuffer = pucPayload;
NetworkBufferDescriptor_t * pxNetworkBuffer;
size_t uxBytesNeeded = sizeof( UDPPacket_t ) + sizeof( NBNSRequest_t );
/* Check for minimum buffer size. */
if( uxBufferLength < uxBytesNeeded )
{
return;
}
/* Read the request flags in host endianness. */
usFlags = usChar2u16( &( pucUDPPayloadBuffer[ offsetof( NBNSRequest_t, usFlags ) ] ) );
if( ( usFlags & dnsNBNS_FLAGS_OPCODE_MASK ) == dnsNBNS_FLAGS_OPCODE_QUERY )
{
usType = usChar2u16( &( pucUDPPayloadBuffer[ offsetof( NBNSRequest_t, usType ) ] ) );
usClass = usChar2u16( &( pucUDPPayloadBuffer[ offsetof( NBNSRequest_t, usClass ) ] ) );
/* Not used for now */
( void ) usClass;
/* For NBNS a name is 16 bytes long, written with capitals only.
* Make sure that the copy is terminated with a zero. */
pucTarget = &( ucNBNSName[ sizeof( ucNBNSName ) - 2U ] );
pucTarget[ 1 ] = ( uint8_t ) 0U;
/* Start with decoding the last 2 bytes. */
pucSource = &( pucUDPPayloadBuffer[ ( dnsNBNS_ENCODED_NAME_LENGTH - 2 ) + offsetof( NBNSRequest_t, ucName ) ] );
for( ; ; )
{
const uint8_t ucCharA = ( uint8_t ) 0x41U;
ucByte = ( ( uint8_t ) ( ( pucSource[ 0 ] - ucCharA ) << 4 ) ) | ( pucSource[ 1 ] - ucCharA );
/* Make sure there are no trailing spaces in the name. */
if( ( ucByte == ( uint8_t ) ' ' ) && ( pucTarget[ 1 ] == 0U ) )
{
ucByte = 0U;
}
*pucTarget = ucByte;
if( pucTarget == ucNBNSName )
{
break;
}
pucTarget -= 1;
pucSource -= 2;
}
#if ( ipconfigUSE_DNS_CACHE == 1 )
{
if( ( usFlags & dnsNBNS_FLAGS_RESPONSE ) != 0U )
{
/* If this is a response from another device,
* add the name to the DNS cache */
( void ) prvProcessDNSCache( ( char * ) ucNBNSName, &( ulIPAddress ), 0, pdFALSE );
}
}
#else
{
/* Avoid compiler warnings. */
( void ) ulIPAddress;
}
#endif /* ipconfigUSE_DNS_CACHE */
if( ( ( usFlags & dnsNBNS_FLAGS_RESPONSE ) == 0U ) &&
( usType == dnsNBNS_TYPE_NET_BIOS ) &&
( xApplicationDNSQueryHook( ( const char * ) ucNBNSName ) != pdFALSE ) )
{
uint16_t usLength;
DNSMessage_t * pxMessage;
NBNSAnswer_t * pxAnswer;
/* Someone is looking for a device with ucNBNSName,
* prepare a positive reply. */
pxNetworkBuffer = pxUDPPayloadBuffer_to_NetworkBuffer( pucUDPPayloadBuffer );
if( ( xBufferAllocFixedSize == pdFALSE ) && ( pxNetworkBuffer != NULL ) )
{
NetworkBufferDescriptor_t * pxNewBuffer;
/* The field xDataLength was set to the total length of the UDP packet,
* i.e. the payload size plus sizeof( UDPPacket_t ). */
pxNewBuffer = pxDuplicateNetworkBufferWithDescriptor( pxNetworkBuffer, pxNetworkBuffer->xDataLength + sizeof( NBNSAnswer_t ) );
if( pxNewBuffer != NULL )
{
pucUDPPayloadBuffer = &( pxNewBuffer->pucEthernetBuffer[ sizeof( UDPPacket_t ) ] );
pxNetworkBuffer = pxNewBuffer;
}
else
{
/* Just prevent that a reply will be sent */
pxNetworkBuffer = NULL;
}
}
/* Should not occur: pucUDPPayloadBuffer is part of a xNetworkBufferDescriptor */
if( pxNetworkBuffer != NULL )
{
pxMessage = ipCAST_PTR_TO_TYPE_PTR( DNSMessage_t, pucUDPPayloadBuffer );
/* As the fields in the structures are not word-aligned, we have to
* copy the values byte-by-byte using macro's vSetField16() and vSetField32() */
#ifndef _lint
vSetField16( pxMessage, DNSMessage_t, usFlags, dnsNBNS_QUERY_RESPONSE_FLAGS ); /* 0x8500 */
vSetField16( pxMessage, DNSMessage_t, usQuestions, 0 );
vSetField16( pxMessage, DNSMessage_t, usAnswers, 1 );
vSetField16( pxMessage, DNSMessage_t, usAuthorityRRs, 0 );
vSetField16( pxMessage, DNSMessage_t, usAdditionalRRs, 0 );
#else
( void ) pxMessage;
#endif
pxAnswer = ipCAST_PTR_TO_TYPE_PTR( NBNSAnswer_t, &( pucUDPPayloadBuffer[ offsetof( NBNSRequest_t, usType ) ] ) );
#ifndef _lint
vSetField16( pxAnswer, NBNSAnswer_t, usType, usType ); /* Type */
vSetField16( pxAnswer, NBNSAnswer_t, usClass, dnsNBNS_CLASS_IN ); /* Class */
vSetField32( pxAnswer, NBNSAnswer_t, ulTTL, dnsNBNS_TTL_VALUE );
vSetField16( pxAnswer, NBNSAnswer_t, usDataLength, 6 ); /* 6 bytes including the length field */
vSetField16( pxAnswer, NBNSAnswer_t, usNbFlags, dnsNBNS_NAME_FLAGS );
vSetField32( pxAnswer, NBNSAnswer_t, ulIPAddress, FreeRTOS_ntohl( *ipLOCAL_IP_ADDRESS_POINTER ) );
#else
( void ) pxAnswer;
#endif
usLength = ( uint16_t ) ( sizeof( NBNSAnswer_t ) + ( size_t ) offsetof( NBNSRequest_t, usType ) );
prvReplyDNSMessage( pxNetworkBuffer, ( BaseType_t ) usLength );
}
}
}
}
#endif /* ipconfigUSE_NBNS */
/*-----------------------------------------------------------*/
/**
* @brief Create a socket and bind it to the standard DNS port number.
*
* @return The created socket - or NULL if the socket could not be created or could not be bound.
*/
static Socket_t prvCreateDNSSocket( void )
{
Socket_t xSocket;
struct freertos_sockaddr xAddress;
BaseType_t xReturn;
/* This must be the first time this function has been called. Create
* the socket. */
xSocket = FreeRTOS_socket( FREERTOS_AF_INET, FREERTOS_SOCK_DGRAM, FREERTOS_IPPROTO_UDP );
if( xSocketValid( xSocket ) == pdFALSE )
{
/* There was an error, return NULL. */
xSocket = NULL;
}
else
{
/* Auto bind the port. */
xAddress.sin_port = 0U;
xReturn = FreeRTOS_bind( xSocket, &xAddress, sizeof( xAddress ) );
/* Check the bind was successful, and clean up if not. */
if( xReturn != 0 )
{
( void ) FreeRTOS_closesocket( xSocket );
xSocket = NULL;
}
else
{
/* The send and receive timeouts will be set later on. */
}
}
return xSocket;
}
/*-----------------------------------------------------------*/
#if ( ( ipconfigUSE_NBNS == 1 ) || ( ipconfigUSE_LLMNR == 1 ) )
/**
* @brief Send a DNS message to be used in NBNS or LLMNR
*
* @param[in] pxNetworkBuffer: The network buffer descriptor with the DNS message.
* @param[in] lNetLength: The length of the DNS message.
*/
static void prvReplyDNSMessage( NetworkBufferDescriptor_t * pxNetworkBuffer,
BaseType_t lNetLength )
{
UDPPacket_t * pxUDPPacket;
IPHeader_t * pxIPHeader;
UDPHeader_t * pxUDPHeader;
size_t uxDataLength;
pxUDPPacket = ipCAST_PTR_TO_TYPE_PTR( UDPPacket_t, pxNetworkBuffer->pucEthernetBuffer );
pxIPHeader = &pxUDPPacket->xIPHeader;
pxUDPHeader = &pxUDPPacket->xUDPHeader;
/* HT: started using defines like 'ipSIZE_OF_xxx' */
pxIPHeader->usLength = FreeRTOS_htons( ( uint16_t ) lNetLength + ipSIZE_OF_IPv4_HEADER + ipSIZE_OF_UDP_HEADER );
/* HT:endian: should not be translated, copying from packet to packet */
pxIPHeader->ulDestinationIPAddress = pxIPHeader->ulSourceIPAddress;
pxIPHeader->ulSourceIPAddress = *ipLOCAL_IP_ADDRESS_POINTER;
pxIPHeader->ucTimeToLive = ipconfigUDP_TIME_TO_LIVE;
pxIPHeader->usIdentification = FreeRTOS_htons( usPacketIdentifier );
usPacketIdentifier++;
pxUDPHeader->usLength = FreeRTOS_htons( ( uint32_t ) lNetLength + ipSIZE_OF_UDP_HEADER );
vFlip_16( pxUDPHeader->usSourcePort, pxUDPHeader->usDestinationPort );
/* Important: tell NIC driver how many bytes must be sent */
uxDataLength = ( ( size_t ) lNetLength ) + ipSIZE_OF_IPv4_HEADER + ipSIZE_OF_UDP_HEADER + ipSIZE_OF_ETH_HEADER;
#if ( ipconfigDRIVER_INCLUDED_TX_IP_CHECKSUM == 0 )
{
/* Calculate the IP header checksum. */
pxIPHeader->usHeaderChecksum = 0U;
pxIPHeader->usHeaderChecksum = usGenerateChecksum( 0U, ( uint8_t * ) &( pxIPHeader->ucVersionHeaderLength ), ipSIZE_OF_IPv4_HEADER );
pxIPHeader->usHeaderChecksum = ~FreeRTOS_htons( pxIPHeader->usHeaderChecksum );
/* calculate the UDP checksum for outgoing package */
( void ) usGenerateProtocolChecksum( ( uint8_t * ) pxUDPPacket, uxDataLength, pdTRUE );
}
#endif
/* Important: tell NIC driver how many bytes must be sent */
pxNetworkBuffer->xDataLength = uxDataLength;
/* This function will fill in the eth addresses and send the packet */
vReturnEthernetFrame( pxNetworkBuffer, pdFALSE );
}
#endif /* ipconfigUSE_NBNS == 1 || ipconfigUSE_LLMNR == 1 */
/*-----------------------------------------------------------*/
#if ( ipconfigUSE_DNS_CACHE == 1 )
/**
* @brief Send a DNS message to be used in NBNS or LLMNR
*
* @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
* @param[in] xLookUp: pdTRUE if a look-up is expected, pdFALSE, when the DNS cache must
* be updated.
*
* @return
*/
static BaseType_t prvProcessDNSCache( const char * pcName,
uint32_t * pulIP,
uint32_t ulTTL,
BaseType_t xLookUp )
{
BaseType_t x;
BaseType_t xFound = pdFALSE;
uint32_t ulCurrentTimeSeconds = ( xTaskGetTickCount() / portTICK_PERIOD_MS ) / 1000UL;
uint32_t ulIPAddressIndex = 0;
static BaseType_t xFreeEntry = 0;
configASSERT( ( pcName != NULL ) );
/* For each entry in the DNS cache table. */
for( x = 0; x < ipconfigDNS_CACHE_ENTRIES; x++ )
{
if( xDNSCache[ x ].pcName[ 0 ] == ( char ) 0 )
{
continue;
}
if( strcmp( xDNSCache[ x ].pcName, pcName ) == 0 )
{
/* Is this function called for a lookup or to add/update an IP address? */
if( xLookUp != pdFALSE )
{
/* Confirm that the record is still fresh. */
if( ulCurrentTimeSeconds < ( xDNSCache[ x ].ulTimeWhenAddedInSeconds + FreeRTOS_ntohl( xDNSCache[ x ].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[ x ].ucCurrentIPAddress % xDNSCache[ x ].ucNumIPAddresses;
ucIndex = ucIndex % ( uint8_t ) ipconfigDNS_CACHE_ADDRESSES_PER_ENTRY;
ulIPAddressIndex = ucIndex;
xDNSCache[ x ].ucCurrentIPAddress++;
#endif /* if ( ipconfigDNS_CACHE_ADDRESSES_PER_ENTRY > 1 ) */
*pulIP = xDNSCache[ x ].ulIPAddresses[ ulIPAddressIndex ];
}
else
{
/* Age out the old cached record. */
xDNSCache[ x ].pcName[ 0 ] = ( char ) 0;
}
}
else
{
#if ( ipconfigDNS_CACHE_ADDRESSES_PER_ENTRY > 1 )
if( xDNSCache[ x ].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[ x ].ucNumIPAddresses;
xDNSCache[ x ].ucNumIPAddresses++;
}
#endif
xDNSCache[ x ].ulIPAddresses[ ulIPAddressIndex ] = *pulIP;
xDNSCache[ x ].ulTTL = ulTTL;
xDNSCache[ x ].ulTimeWhenAddedInSeconds = ulCurrentTimeSeconds;
}
xFound = pdTRUE;
break;
}
}
if( xFound == pdFALSE )
{
if( xLookUp != pdFALSE )
{
*pulIP = 0UL;
}
else
{
/* Add or update the item. */
if( strlen( pcName ) < ( size_t ) ipconfigDNS_CACHE_NAME_LENGTH )
{
( void ) strcpy( xDNSCache[ xFreeEntry ].pcName, pcName );
xDNSCache[ xFreeEntry ].ulIPAddresses[ 0 ] = *pulIP;
xDNSCache[ xFreeEntry ].ulTTL = ulTTL;
xDNSCache[ xFreeEntry ].ulTimeWhenAddedInSeconds = ulCurrentTimeSeconds;
#if ( ipconfigDNS_CACHE_ADDRESSES_PER_ENTRY > 1 )
xDNSCache[ xFreeEntry ].ucNumIPAddresses = 1;
xDNSCache[ xFreeEntry ].ucCurrentIPAddress = 0;
/* Initialize all remaining IP addresses in this entry to 0 */
( void ) memset( &xDNSCache[ xFreeEntry ].ulIPAddresses[ 1 ],
0,
sizeof( xDNSCache[ xFreeEntry ].ulIPAddresses[ 1 ] ) *
( ( uint32_t ) ipconfigDNS_CACHE_ADDRESSES_PER_ENTRY - 1U ) );
#endif
xFreeEntry++;
if( xFreeEntry == ipconfigDNS_CACHE_ENTRIES )
{
xFreeEntry = 0;
}
}
}
}
if( ( xLookUp == 0 ) || ( *pulIP != 0UL ) )
{
FreeRTOS_debug_printf( ( "prvProcessDNSCache: %s: '%s' @ %lxip\n", ( xLookUp != 0 ) ? "look-up" : "add", pcName, FreeRTOS_ntohl( *pulIP ) ) );
}
return xFound;
}
#endif /* ipconfigUSE_DNS_CACHE */
#endif /* ipconfigUSE_DNS != 0 */
/*-----------------------------------------------------------*/
/* Provide access to private members for testing. */
#ifdef FREERTOS_ENABLE_UNIT_TESTS
#include "freertos_tcp_test_access_dns_define.h"
#endif
Reference in New Issue Copy Permalink