mirror of
https://github.com/FreeRTOS/FreeRTOS-Plus-TCP
synced 2025-10-20 22:10:04 +08:00
6b84c44e07
* MISRA: fix rule 8.13 violations * Fix more 8.3 rules violation * Misra rule 8.13 fixes * Fix Unit Test
821 lines
30 KiB
C
821 lines
30 KiB
C
/*
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* FreeRTOS+TCP <DEVELOPMENT BRANCH>
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* Copyright (C) 2021 Amazon.com, Inc. or its affiliates. All Rights Reserved.
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*
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* SPDX-License-Identifier: MIT
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy of
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* this software and associated documentation files (the "Software"), to deal in
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* the Software without restriction, including without limitation the rights to
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* use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
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* the Software, and to permit persons to whom the Software is furnished to do so,
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* subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in all
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* copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
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* FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
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* COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
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* IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
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* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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*
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* http://aws.amazon.com/freertos
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* http://www.FreeRTOS.org
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*/
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/**
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* @file FreeRTOS_DNS.c
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* @brief Implements the Domain Name System for the FreeRTOS+TCP network stack.
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*/
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/* Standard includes. */
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#include <stdint.h>
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#include <stdio.h>
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/* FreeRTOS includes. */
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#include "FreeRTOS.h"
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#include "task.h"
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#include "semphr.h"
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/* FreeRTOS+TCP includes. */
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#include "FreeRTOS_DNS_Globals.h"
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#include "FreeRTOS_IP.h"
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#include "FreeRTOS_IP_Private.h"
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#include "FreeRTOS_UDP_IP.h"
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#include "FreeRTOS_DNS.h"
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#include "FreeRTOS_DHCP.h"
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#include "NetworkBufferManagement.h"
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#include "NetworkInterface.h"
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#include "FreeRTOS_DNS_Cache.h"
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#include "FreeRTOS_DNS_Parser.h"
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#include "FreeRTOS_DNS_Networking.h"
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#include "FreeRTOS_DNS_Callback.h"
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/* Exclude the entire file if DNS is not enabled. */
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#if ( ipconfigUSE_DNS != 0 )
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/*
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* Create the DNS message in the zero copy buffer passed in the first parameter.
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*/
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_static size_t prvCreateDNSMessage( uint8_t * pucUDPPayloadBuffer,
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const char * pcHostName,
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TickType_t uxIdentifier );
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/*
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* Check if hostname is already known. If not, call prvGetHostByName() to send a DNS request.
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*/
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#if ( ipconfigDNS_USE_CALLBACKS == 1 )
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static uint32_t prvPrepareLookup( const char * pcHostName,
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FOnDNSEvent pCallback,
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void * pvSearchID,
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TickType_t uxTimeout );
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#else
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static uint32_t prvPrepareLookup( const char * pcHostName );
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#endif
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/*
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* Prepare and send a message to a DNS server. 'uxReadTimeOut_ticks' will be passed as
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* zero, in case the user has supplied a call-back function.
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*/
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static uint32_t prvGetHostByName( const char * pcHostName,
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TickType_t uxIdentifier,
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TickType_t uxReadTimeOut_ticks );
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#if ( ipconfigUSE_LLMNR == 1 )
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/** @brief The MAC address used for LLMNR. */
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const MACAddress_t xLLMNR_MacAdress = { { 0x01, 0x00, 0x5e, 0x00, 0x00, 0xfc } };
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#endif /* ipconfigUSE_LLMNR == 1 */
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/*-----------------------------------------------------------*/
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/**
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* @brief A DNS query consists of a header, as described in 'struct xDNSMessage'
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* It is followed by 1 or more queries, each one consisting of a name and a tail,
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* with two fields: type and class
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*/
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#include "pack_struct_start.h"
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struct xDNSTail
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{
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uint16_t usType; /**< Type of DNS message. */
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uint16_t usClass; /**< Class of DNS message. */
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}
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#include "pack_struct_end.h"
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typedef struct xDNSTail DNSTail_t;
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/*-----------------------------------------------------------*/
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#if ( ipconfigDNS_USE_CALLBACKS == 1 )
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/**
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* @brief Define FreeRTOS_gethostbyname() as a normal blocking call.
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* @param[in] pcHostName: The hostname whose IP address is being searched for.
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* @return The IP-address of the hostname.
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*/
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uint32_t FreeRTOS_gethostbyname( const char * pcHostName )
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{
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return FreeRTOS_gethostbyname_a( pcHostName, NULL, ( void * ) NULL, 0U );
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}
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/*-----------------------------------------------------------*/
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/** @brief Initialise the list of call-back structures.
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*/
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void vDNSInitialise( void )
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{
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vDNSCallbackInitialise();
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}
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/*-----------------------------------------------------------*/
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/**
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* @brief Remove the entry defined by the search ID to cancel a DNS request.
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* @param[in] pvSearchID: The search ID of the callback function associated with
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* the DNS request being cancelled. Note that the value of
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* the pointer matters, not the pointee.
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*/
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void FreeRTOS_gethostbyname_cancel( void * pvSearchID )
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{
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/* _HT_ Should better become a new API call to have the IP-task remove the callback */
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vDNSCheckCallBack( pvSearchID );
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}
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/*-----------------------------------------------------------*/
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/*-----------------------------------------------------------*/
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#endif /* ipconfigDNS_USE_CALLBACKS == 1 */
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/*-----------------------------------------------------------*/
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#if ( ipconfigDNS_USE_CALLBACKS == 0 )
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/**
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* @brief Get the IP-address corresponding to the given hostname.
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* @param[in] pcHostName: The hostname whose IP address is being queried.
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* @return The IP-address corresponding to the hostname. 0 is returned in
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* case of failure.
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*/
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uint32_t FreeRTOS_gethostbyname( const char * pcHostName )
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{
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return prvPrepareLookup( pcHostName );
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}
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#else
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/**
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* @brief Get the IP-address corresponding to the given hostname.
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* @param[in] pcHostName: The hostname whose IP address is being queried.
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* @param[in] pCallback: The callback function which will be called upon DNS response.
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* @param[in] pvSearchID: Search ID for the callback function.
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* @param[in] uxTimeout: Timeout for the callback function.
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* @return The IP-address corresponding to the hostname. 0 is returned in case of
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* failure.
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*/
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uint32_t FreeRTOS_gethostbyname_a( const char * pcHostName,
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FOnDNSEvent pCallback,
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void * pvSearchID,
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TickType_t uxTimeout )
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{
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return prvPrepareLookup( pcHostName, pCallback, pvSearchID, uxTimeout );
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}
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#endif /* if ( ipconfigDNS_USE_CALLBACKS == 0 ) */
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#if ( ipconfigDNS_USE_CALLBACKS == 1 )
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/**
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* @brief Check if hostname is already known. If not, call prvGetHostByName() to send a DNS request.
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*
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* @param[in] pcHostName: The hostname whose IP address is being queried.
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* @param[in] pCallback: The callback function which will be called upon DNS response.
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* @param[in] pvSearchID: Search ID for the callback function.
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* @param[in] uxTimeout: Timeout for the callback function.
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* @return The IP-address corresponding to the hostname.
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*/
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static uint32_t prvPrepareLookup( const char * pcHostName,
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FOnDNSEvent pCallback,
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void * pvSearchID,
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TickType_t uxTimeout )
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#else
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/**
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* @brief Check if hostname is already known. If not, call prvGetHostByName() to send a DNS request.
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* @param[in] pcHostName: The hostname whose IP address is being queried.
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* @return The IP-address corresponding to the hostname.
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*/
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static uint32_t prvPrepareLookup( const char * pcHostName )
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#endif
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{
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uint32_t ulIPAddress = 0U;
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TickType_t uxReadTimeOut_ticks = ipconfigDNS_RECEIVE_BLOCK_TIME_TICKS;
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/* Generate a unique identifier for this query. Keep it in a local variable
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* as gethostbyname() may be called from different threads */
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BaseType_t xHasRandom = pdFALSE;
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TickType_t uxIdentifier = 0U;
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BaseType_t xLengthOk = pdFALSE;
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if( pcHostName != NULL )
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{
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size_t xLength = strlen( pcHostName ) + 1U;
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#if ( ipconfigUSE_DNS_CACHE != 0 )
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if( xLength <= ipconfigDNS_CACHE_NAME_LENGTH )
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#else
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if( xLength <= dnsMAX_HOSTNAME_LENGTH )
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#endif
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{
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/* The name is not too long. */
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xLengthOk = pdTRUE;
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}
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else
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{
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FreeRTOS_printf( ( "prvPrepareLookup: name is too long ( %lu > %lu )\n",
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( uint32_t ) xLength,
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( uint32_t ) ipconfigDNS_CACHE_NAME_LENGTH ) );
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}
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}
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if( ( pcHostName != NULL ) && ( xLengthOk != pdFALSE ) )
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{
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/* If the supplied hostname is IP address, convert it to uint32_t
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* and return. */
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#if ( ipconfigINCLUDE_FULL_INET_ADDR == 1 )
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{
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ulIPAddress = FreeRTOS_inet_addr( pcHostName );
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}
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#endif /* ipconfigINCLUDE_FULL_INET_ADDR == 1 */
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#if ( ipconfigUSE_DNS_CACHE == 1 )
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/* Check the cache before issuing another DNS request. */
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if( ulIPAddress == 0U )
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{
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ulIPAddress = FreeRTOS_dnslookup( pcHostName );
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if( ulIPAddress != 0U )
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{
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FreeRTOS_debug_printf( ( "FreeRTOS_gethostbyname: found '%s' in cache: %lxip\n", pcHostName, ulIPAddress ) );
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}
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else
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{
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/* prvGetHostByName will be called to start a DNS lookup. */
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}
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}
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#endif /* if ( ipconfigUSE_DNS_CACHE == 1 ) */
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/* Generate a unique identifier. */
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if( ulIPAddress == 0U )
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{
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uint32_t ulNumber;
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xHasRandom = xApplicationGetRandomNumber( &( ulNumber ) );
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/* DNS identifiers are 16-bit. */
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uxIdentifier = ( TickType_t ) ( ulNumber & 0xffffU );
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}
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#if ( ipconfigDNS_USE_CALLBACKS == 1 )
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{
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if( pCallback != NULL )
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{
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if( ulIPAddress == 0U )
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{
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/* The user has provided a callback function, so do not block on recvfrom() */
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if( xHasRandom != pdFALSE )
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{
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uxReadTimeOut_ticks = 0U;
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vDNSSetCallBack( pcHostName,
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pvSearchID,
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pCallback,
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uxTimeout,
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uxIdentifier );
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}
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}
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else
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{
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/* The IP address is known, do the call-back now. */
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pCallback( pcHostName, pvSearchID, ulIPAddress );
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}
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}
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}
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#endif /* if ( ipconfigDNS_USE_CALLBACKS == 1 ) */
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if( ( ulIPAddress == 0U ) && ( xHasRandom != pdFALSE ) )
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{
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ulIPAddress = prvGetHostByName( pcHostName,
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uxIdentifier,
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uxReadTimeOut_ticks );
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}
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}
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return ulIPAddress;
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}
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/*-----------------------------------------------------------*/
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#if ( ipconfigUSE_LLMNR == 1 )
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/*!
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* @brief If LLMNR is being used then determine if the host name includes a '.'
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* if not then LLMNR can be used as the lookup method.
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* @param [in] pcHostName hostname to check
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* @returns true if the hostname is a dotted format, else false
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*
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*/
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static BaseType_t llmnr_has_dot( const char * pcHostName )
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{
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BaseType_t bHasDot = pdFALSE;
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const char * pucPtr;
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for( pucPtr = pcHostName; *pucPtr != ( char ) 0; pucPtr++ )
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{
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if( *pucPtr == '.' )
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{
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bHasDot = pdTRUE;
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break;
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}
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}
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return bHasDot;
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}
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#endif /* if ( ipconfigUSE_LLMNR == 1 ) */
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/*!
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* @brief create a payload buffer and return it through the parameter
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* @param [out] ppxNetworkBuffer network buffer to create
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* @param [in] pcHostName hostname to get its length
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* @returns pointer address to the payload buffer
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*
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*/
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static uint8_t * prvGetPayloadBuffer( NetworkBufferDescriptor_t ** ppxNetworkBuffer,
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const char * pcHostName )
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{
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size_t uxExpectedPayloadLength;
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uint8_t * pucUDPPayloadBuffer = NULL;
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size_t uxHeaderBytes;
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uxHeaderBytes = ipSIZE_OF_ETH_HEADER +
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ipSIZE_OF_IPv4_HEADER +
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ipSIZE_OF_UDP_HEADER;
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uxExpectedPayloadLength = sizeof( DNSMessage_t ) +
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strlen( pcHostName ) +
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sizeof( uint16_t ) +
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sizeof( uint16_t ) + 2U;
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/* Get a buffer. This uses a maximum delay, but the delay will be
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* capped to ipconfigUDP_MAX_SEND_BLOCK_TIME_TICKS so the return value
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* still needs to be tested. */
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*ppxNetworkBuffer = pxGetNetworkBufferWithDescriptor( uxExpectedPayloadLength +
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uxHeaderBytes,
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0U );
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if( *ppxNetworkBuffer != NULL )
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{
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pucUDPPayloadBuffer = &( ( *ppxNetworkBuffer )->pucEthernetBuffer[ uxHeaderBytes ] );
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}
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return pucUDPPayloadBuffer;
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}
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/*!
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* @brief fill pxAddress from pucUDPPayloadBuffer
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* @param [out] pxAddress ip address and port ... structure
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* @param [in] pcHostName hostname to get its length
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*/
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static void prvFillSockAddress( struct freertos_sockaddr * pxAddress,
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const char * pcHostName )
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{
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uint32_t ulIPAddress = 0U;
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#if ( ipconfigUSE_LLMNR != 1 )
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( void ) pcHostName;
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#endif
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/* Obtain the DNS server address. */
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FreeRTOS_GetAddressConfiguration( NULL, NULL, NULL, &ulIPAddress );
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#if ( ipconfigUSE_LLMNR == 1 )
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BaseType_t bHasDot = llmnr_has_dot( pcHostName );
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if( bHasDot == pdFALSE )
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{
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/* Use LLMNR addressing. */
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pxAddress->sin_addr = ipLLMNR_IP_ADDR; /* Is in network byte order. */
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pxAddress->sin_port = ipLLMNR_PORT;
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pxAddress->sin_port = FreeRTOS_ntohs( pxAddress->sin_port );
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}
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else
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#endif /* if ( ipconfigUSE_LLMNR == 1 ) */
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{
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/* Use DNS server. */
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pxAddress->sin_addr = ulIPAddress;
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pxAddress->sin_port = dnsDNS_PORT;
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}
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}
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/*!
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* @brief return ip address from the dns reply message
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* @param [in] pxReceiveBuffer received buffer from the DNS server
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* @param [in] uxIdentifier matches sent and received packets
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* @returns ip address or zero on error
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*
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*/
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static uint32_t prvDNSReply( const struct xDNSBuffer * pxReceiveBuffer,
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TickType_t uxIdentifier )
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{
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uint32_t ulIPAddress = 0U;
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BaseType_t xExpected;
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const DNSMessage_t * pxDNSMessageHeader =
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( ( const DNSMessage_t * )
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pxReceiveBuffer->pucPayloadBuffer );
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/* See if the identifiers match. */
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if( uxIdentifier == ( TickType_t ) pxDNSMessageHeader->usIdentifier )
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{
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xExpected = pdTRUE;
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}
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else
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{
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xExpected = pdFALSE;
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}
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/* The reply was received. Process it. */
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#if ( ipconfigDNS_USE_CALLBACKS == 0 )
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/* It is useless to analyse the unexpected reply
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* unless asynchronous look-ups are enabled. */
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if( xExpected != pdFALSE )
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#endif /* ipconfigDNS_USE_CALLBACKS == 0 */
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{
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ulIPAddress = DNS_ParseDNSReply( pxReceiveBuffer->pucPayloadBuffer,
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pxReceiveBuffer->uxPayloadLength,
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xExpected );
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}
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return ulIPAddress;
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}
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|
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/*!
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* @brief prepare the buffer before sending
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* @param [in] pcHostName
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* @param [in] uxIdentifier matches sent and received packets
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* @param [in] xDNSSocket a valid socket
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* @param [in] pxAddress address structure
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* @returns pdTRUE if sending the data was successful, pdFALSE otherwise.
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*/
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static BaseType_t prvSendBuffer( const char * pcHostName,
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TickType_t uxIdentifier,
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Socket_t xDNSSocket,
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const struct freertos_sockaddr * pxAddress )
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{
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BaseType_t uxReturn = pdFAIL;
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struct xDNSBuffer xDNSBuf = { 0 };
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NetworkBufferDescriptor_t * pxNetworkBuffer = NULL;
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/*get dns message buffer */
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xDNSBuf.pucPayloadBuffer = prvGetPayloadBuffer( &pxNetworkBuffer,
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pcHostName );
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if( xDNSBuf.pucPayloadBuffer != NULL )
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{
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xDNSBuf.uxPayloadSize = pxNetworkBuffer->xDataLength;
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#if ( ipconfigUSE_LLMNR == 1 )
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{
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if( FreeRTOS_ntohs( pxAddress->sin_port ) == ipLLMNR_PORT )
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{
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( ( ( DNSMessage_t * ) xDNSBuf.pucPayloadBuffer ) )->usFlags = 0;
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}
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}
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#endif
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xDNSBuf.uxPayloadLength = prvCreateDNSMessage( xDNSBuf.pucPayloadBuffer,
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pcHostName,
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uxIdentifier );
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/* send the dns message */
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uxReturn = DNS_SendRequest( xDNSSocket,
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pxAddress,
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&xDNSBuf );
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if( uxReturn == pdFAIL )
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{
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vReleaseNetworkBufferAndDescriptor( pxNetworkBuffer );
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}
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}
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return uxReturn;
|
|
}
|
|
|
|
/*!
|
|
* @brief main dns operation description function
|
|
* @param [in] pcHostName hostname to get its ip address
|
|
* @param [in] uxIdentifier Identifier to match sent and received packets
|
|
* @param [in] xDNSSocket socket
|
|
* @returns ip address or zero on error
|
|
*/
|
|
static uint32_t prvGetHostByNameOp( const char * pcHostName,
|
|
TickType_t uxIdentifier,
|
|
Socket_t xDNSSocket )
|
|
{
|
|
uint32_t ulIPAddress = 0;
|
|
|
|
struct freertos_sockaddr xAddress;
|
|
struct xDNSBuffer xReceiveBuffer = { 0 };
|
|
BaseType_t uxReturn = pdFAIL;
|
|
|
|
prvFillSockAddress( &xAddress, pcHostName );
|
|
|
|
do
|
|
{
|
|
uxReturn = prvSendBuffer( pcHostName,
|
|
uxIdentifier,
|
|
xDNSSocket,
|
|
&xAddress );
|
|
|
|
if( uxReturn == pdFAIL )
|
|
{
|
|
break;
|
|
}
|
|
|
|
/* Create the message in the obtained buffer. */
|
|
|
|
/* receive a dns reply message */
|
|
DNS_ReadReply( xDNSSocket,
|
|
&xAddress,
|
|
&xReceiveBuffer );
|
|
|
|
if( xReceiveBuffer.pucPayloadBuffer == NULL )
|
|
{
|
|
break;
|
|
}
|
|
|
|
ulIPAddress = prvDNSReply( &xReceiveBuffer, uxIdentifier );
|
|
|
|
/* Finished with the buffer. The zero copy interface
|
|
* is being used, so the buffer must be freed by the
|
|
* task. */
|
|
FreeRTOS_ReleaseUDPPayloadBuffer( xReceiveBuffer.pucPayloadBuffer );
|
|
} while( 0 );
|
|
|
|
return ulIPAddress;
|
|
}
|
|
|
|
/*!
|
|
* @brief helper function to prvGetHostByNameOP with multiple retries equal to
|
|
* ipconfigDNS_REQUEST_ATTEMPTS
|
|
*
|
|
* @param [in] pcHostName hostname to get its ip address
|
|
* @param [in] uxIdentifier Identifier to match sent and received packets
|
|
* @param [in] xDNSSocket socket
|
|
* @returns ip address or zero on error
|
|
*
|
|
*/
|
|
static uint32_t prvGetHostByNameOp_WithRetry( const char * pcHostName,
|
|
TickType_t uxIdentifier,
|
|
Socket_t xDNSSocket )
|
|
{
|
|
uint32_t ulIPAddress;
|
|
BaseType_t xAttempt;
|
|
|
|
for( xAttempt = 0; xAttempt < ipconfigDNS_REQUEST_ATTEMPTS; xAttempt++ )
|
|
{
|
|
ulIPAddress = prvGetHostByNameOp( pcHostName,
|
|
uxIdentifier,
|
|
xDNSSocket );
|
|
|
|
if( ulIPAddress != 0U )
|
|
{ /* ip found, no need to retry */
|
|
break;
|
|
}
|
|
}
|
|
|
|
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 match sent and received packets
|
|
* @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 )
|
|
{
|
|
Socket_t xDNSSocket;
|
|
uint32_t ulIPAddress = 0U;
|
|
|
|
xDNSSocket = DNS_CreateSocket( uxReadTimeOut_ticks );
|
|
|
|
if( xDNSSocket != NULL )
|
|
{
|
|
if( uxReadTimeOut_ticks == 0U )
|
|
{
|
|
ulIPAddress = prvGetHostByNameOp( pcHostName,
|
|
uxIdentifier,
|
|
xDNSSocket );
|
|
}
|
|
else
|
|
{
|
|
ulIPAddress = prvGetHostByNameOp_WithRetry( pcHostName,
|
|
uxIdentifier,
|
|
xDNSSocket );
|
|
}
|
|
|
|
/* Finished with the socket. */
|
|
DNS_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 Identifier to match sent and received packets
|
|
* @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 = ( ( 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 = ( ( 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;
|
|
}
|
|
|
|
/*-----------------------------------------------------------*/
|
|
|
|
/* 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 pdFAIL Always 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 ) DNS_ParseDNSReply( 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 = ( ( UDPPacket_t * )
|
|
pxNetworkBuffer->pucEthernetBuffer );
|
|
uint8_t * pucUDPPayloadBuffer = &( pxNetworkBuffer->pucEthernetBuffer[ sizeof( *pxUDPPacket ) ] );
|
|
|
|
size_t uxBytesNeeded = sizeof( UDPPacket_t ) + sizeof( NBNSRequest_t );
|
|
|
|
/* Check for minimum buffer size. */
|
|
if( pxNetworkBuffer->xDataLength >= uxBytesNeeded )
|
|
{
|
|
DNS_TreatNBNS( pucUDPPayloadBuffer,
|
|
pxNetworkBuffer->xDataLength,
|
|
pxUDPPacket->xIPHeader.ulSourceIPAddress );
|
|
}
|
|
|
|
/* The packet was not consumed. */
|
|
return pdFAIL;
|
|
}
|
|
|
|
#endif /* ipconfigUSE_NBNS */
|
|
|
|
/*-----------------------------------------------------------*/
|
|
|
|
#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
|