diff options
Diffstat (limited to 'FreeRTOS-Labs/Source/FreeRTOS-Plus-TCP/FreeRTOS_DNS.c')
| -rw-r--r-- | FreeRTOS-Labs/Source/FreeRTOS-Plus-TCP/FreeRTOS_DNS.c | 1422 |
1 files changed, 1422 insertions, 0 deletions
diff --git a/FreeRTOS-Labs/Source/FreeRTOS-Plus-TCP/FreeRTOS_DNS.c b/FreeRTOS-Labs/Source/FreeRTOS-Plus-TCP/FreeRTOS_DNS.c new file mode 100644 index 000000000..de53b3eb8 --- /dev/null +++ b/FreeRTOS-Labs/Source/FreeRTOS-Plus-TCP/FreeRTOS_DNS.c @@ -0,0 +1,1422 @@ +/*
+ * FreeRTOS+TCP 191100 experimental
+ * Copyright (C) 2018 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
+ */
+
+/* Standard includes. */
+#include <stdint.h>
+
+/* FreeRTOS includes. */
+#include "FreeRTOS.h"
+#include "task.h"
+#include "queue.h"
+#include "list.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 "NetworkBufferManagement.h"
+#include "NetworkInterface.h"
+#include "IPTraceMacroDefaults.h"
+
+/* Exclude the entire file if DNS is not enabled. */
+#if( ipconfigUSE_DNS != 0 )
+
+#if( ipconfigBYTE_ORDER == pdFREERTOS_LITTLE_ENDIAN )
+ #define dnsDNS_PORT 0x3500
+ #define dnsONE_QUESTION 0x0100
+ #define dnsOUTGOING_FLAGS 0x0001 /* Standard query. */
+ #define dnsRX_FLAGS_MASK 0x0f80 /* The bits of interest in the flags field of incoming DNS messages. */
+ #define dnsEXPECTED_RX_FLAGS 0x0080 /* Should be a response, without any errors. */
+#else
+ #define dnsDNS_PORT 0x0035
+ #define dnsONE_QUESTION 0x0001
+ #define dnsOUTGOING_FLAGS 0x0100 /* Standard query. */
+ #define dnsRX_FLAGS_MASK 0x800f /* The bits of interest in the flags field of incoming DNS messages. */
+ #define dnsEXPECTED_RX_FLAGS 0x8000 /* Should be a response, without any errors. */
+
+#endif /* ipconfigBYTE_ORDER */
+
+/* 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
+
+/* 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. */
+#define dnsNBNS_FLAGS_RESPONSE 0x8000
+#define dnsNBNS_FLAGS_OPCODE_MASK 0x7800
+#define dnsNBNS_FLAGS_OPCODE_QUERY 0x0000
+#define dnsNBNS_FLAGS_OPCODE_REGISTRATION 0x2800
+
+/* Host types. */
+#define dnsTYPE_A_HOST 0x01
+#define dnsCLASS_IN 0x01
+
+/* LLMNR constants. */
+#define dnsLLMNR_TTL_VALUE 300000
+#define dnsLLMNR_FLAGS_IS_REPONSE 0x8000
+
+/* NBNS constants. */
+#define dnsNBNS_TTL_VALUE 3600 /* 1 hour valid */
+#define dnsNBNS_TYPE_NET_BIOS 0x0020
+#define dnsNBNS_CLASS_IN 0x01
+#define dnsNBNS_NAME_FLAGS 0x6000
+#define dnsNBNS_ENCODED_NAME_LENGTH 32
+
+/* 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 ( 0x8500 )
+
+/* Flag DNS parsing errors in situations where an IPv4 address is the return
+type. */
+#define dnsPARSE_ERROR 0UL
+
+/*
+ * 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 xIdentifier );
+
+/*
+ * Simple routine that jumps over the NAME field of a resource record.
+ */
+static uint8_t *prvSkipNameField( uint8_t *pucByte, size_t xSourceLen );
+
+/*
+ * Process a response packet from a DNS server.
+ */
+static uint32_t prvParseDNSReply( uint8_t *pucUDPPayloadBuffer, size_t xBufferLength, TickType_t xIdentifier );
+
+/*
+ * Prepare and send a message to a DNS server. 'xReadTimeOut_ms' will be passed as
+ * zero, in case the user has supplied a call-back function.
+ */
+static uint32_t prvGetHostByName( const char *pcHostName, TickType_t xIdentifier, TickType_t xReadTimeOut_ms );
+
+/*
+ * 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 *pucUDPPayloadBuffer, size_t xBufferLength, uint32_t ulIPAddress );
+#endif /* ipconfigUSE_NBNS */
+
+#if( ipconfigUSE_DNS_CACHE == 1 )
+ static uint8_t *prvReadNameField( uint8_t *pucByte, size_t xSourceLen, char *pcName, size_t xLen );
+ static void prvProcessDNSCache( const char *pcName, uint32_t *pulIP, uint32_t ulTTL, BaseType_t xLookUp );
+
+ typedef struct xDNS_CACHE_TABLE_ROW
+ {
+ uint32_t ulIPAddress; /* The IP address 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;
+ } DNSCacheRow_t;
+
+ static DNSCacheRow_t xDNSCache[ ipconfigDNS_CACHE_ENTRIES ];
+
+ void FreeRTOS_dnsclear()
+ {
+ memset( xDNSCache, 0x0, sizeof( xDNSCache ) );
+ }
+#endif /* ipconfigUSE_DNS_CACHE == 1 */
+
+#if( ipconfigUSE_LLMNR == 1 )
+ const MACAddress_t xLLMNR_MacAdress = { { 0x01, 0x00, 0x5e, 0x00, 0x00, 0xfc } };
+#endif /* ipconfigUSE_LLMNR == 1 */
+
+/*-----------------------------------------------------------*/
+
+#include "pack_struct_start.h"
+struct xDNSMessage
+{
+ uint16_t usIdentifier;
+ uint16_t usFlags;
+ uint16_t usQuestions;
+ uint16_t usAnswers;
+ uint16_t usAuthorityRRs;
+ uint16_t usAdditionalRRs;
+}
+#include "pack_struct_end.h"
+typedef struct xDNSMessage DNSMessage_t;
+
+/* 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;
+ uint16_t usClass;
+}
+#include "pack_struct_end.h"
+typedef struct xDNSTail DNSTail_t;
+
+/* DNS answer record header. */
+#include "pack_struct_start.h"
+struct xDNSAnswerRecord
+{
+ uint16_t usType;
+ uint16_t usClass;
+ uint32_t ulTTL;
+ uint16_t usDataLength;
+}
+#include "pack_struct_end.h"
+typedef struct xDNSAnswerRecord DNSAnswerRecord_t;
+
+#if( ipconfigUSE_LLMNR == 1 )
+
+ #include "pack_struct_start.h"
+ struct xLLMNRAnswer
+ {
+ uint8_t ucNameCode;
+ uint8_t ucNameOffset; /* The name is not repeated in the answer, only the offset is given with "0xc0 <offs>" */
+ uint16_t usType;
+ uint16_t usClass;
+ uint32_t ulTTL;
+ uint16_t usDataLength;
+ uint32_t ulIPAddress;
+ }
+ #include "pack_struct_end.h"
+ typedef struct xLLMNRAnswer LLMNRAnswer_t;
+
+#endif /* ipconfigUSE_LLMNR == 1 */
+
+#if( ipconfigUSE_NBNS == 1 )
+
+ #include "pack_struct_start.h"
+ struct xNBNSRequest
+ {
+ uint16_t usRequestId;
+ uint16_t usFlags;
+ uint16_t ulRequestCount;
+ uint16_t usAnswerRSS;
+ uint16_t usAuthRSS;
+ uint16_t usAdditionalRSS;
+ uint8_t ucNameSpace;
+ uint8_t ucName[ dnsNBNS_ENCODED_NAME_LENGTH ];
+ uint8_t ucNameZero;
+ uint16_t usType;
+ uint16_t usClass;
+ }
+ #include "pack_struct_end.h"
+ typedef struct xNBNSRequest NBNSRequest_t;
+
+ #include "pack_struct_start.h"
+ struct xNBNSAnswer
+ {
+ uint16_t usType;
+ uint16_t usClass;
+ uint32_t ulTTL;
+ uint16_t usDataLength;
+ uint16_t usNbFlags; /* NetBIOS flags 0x6000 : IP-address, big-endian */
+ uint32_t ulIPAddress;
+ }
+ #include "pack_struct_end.h"
+ typedef struct xNBNSAnswer NBNSAnswer_t;
+
+#endif /* ipconfigUSE_NBNS == 1 */
+
+/*-----------------------------------------------------------*/
+
+#if( ipconfigUSE_DNS_CACHE == 1 )
+ uint32_t FreeRTOS_dnslookup( const char *pcHostName )
+ {
+ uint32_t ulIPAddress = 0UL;
+ prvProcessDNSCache( pcHostName, &ulIPAddress, 0, pdTRUE );
+ return ulIPAddress;
+ }
+#endif /* ipconfigUSE_DNS_CACHE == 1 */
+/*-----------------------------------------------------------*/
+
+#if( ipconfigDNS_USE_CALLBACKS != 0 )
+
+ typedef struct xDNS_Callback {
+ TickType_t xRemaningTime; /* Timeout in ms */
+ FOnDNSEvent pCallbackFunction; /* Function to be called when the address has been found or when a timeout has beeen reached */
+ TimeOut_t xTimeoutState;
+ void *pvSearchID;
+ struct xLIST_ITEM xListItem;
+ char pcName[ 1 ];
+ } DNSCallback_t;
+
+ static List_t xCallbackList;
+
+ /* Define FreeRTOS_gethostbyname() as a normal blocking call. */
+ uint32_t FreeRTOS_gethostbyname( const char *pcHostName )
+ {
+ return FreeRTOS_gethostbyname_a( pcHostName, ( FOnDNSEvent ) NULL, ( void* )NULL, 0 );
+ }
+ /*-----------------------------------------------------------*/
+
+ /* Initialise the list of call-back structures. */
+ void vDNSInitialise( void );
+ void vDNSInitialise( void )
+ {
+ vListInitialise( &xCallbackList );
+ }
+ /*-----------------------------------------------------------*/
+
+ /* Iterate through the list of call-back structures and remove
+ old entries which have reached a timeout.
+ As soon as the list hase become empty, the DNS timer will be stopped
+ In case pvSearchID is supplied, the user wants to cancel a DNS request
+ */
+ void vDNSCheckCallBack( void *pvSearchID );
+ void vDNSCheckCallBack( void *pvSearchID )
+ {
+ const ListItem_t *pxIterator;
+ const MiniListItem_t* xEnd = ( const MiniListItem_t* )listGET_END_MARKER( &xCallbackList );
+
+ vTaskSuspendAll();
+ {
+ for( pxIterator = ( const ListItem_t * ) listGET_NEXT( xEnd );
+ pxIterator != ( const ListItem_t * ) xEnd;
+ )
+ {
+ DNSCallback_t *pxCallback = ( 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 ) )
+ {
+ uxListRemove( &pxCallback->xListItem );
+ vPortFree( pxCallback );
+ }
+ else if( xTaskCheckForTimeOut( &pxCallback->xTimeoutState, &pxCallback->xRemaningTime ) != pdFALSE )
+ {
+ pxCallback->pCallbackFunction( pxCallback->pcName, pxCallback->pvSearchID, 0 );
+ uxListRemove( &pxCallback->xListItem );
+ vPortFree( ( void * ) pxCallback );
+ }
+ }
+ }
+ xTaskResumeAll();
+
+ if( listLIST_IS_EMPTY( &xCallbackList ) )
+ {
+ vIPSetDnsTimerEnableState( pdFALSE );
+ }
+ }
+ /*-----------------------------------------------------------*/
+
+ void FreeRTOS_gethostbyname_cancel( void *pvSearchID )
+ {
+ /* _HT_ Should better become a new API call to have the IP-task remove the callback */
+ vDNSCheckCallBack( pvSearchID );
+ }
+ /*-----------------------------------------------------------*/
+
+ /* FreeRTOS_gethostbyname_a() was called along with callback parameters.
+ Store them in a list for later reference. */
+ static void vDNSSetCallBack( const char *pcHostName, void *pvSearchID, FOnDNSEvent pCallbackFunction, TickType_t xTimeout, TickType_t xIdentifier );
+ static void vDNSSetCallBack( const char *pcHostName, void *pvSearchID, FOnDNSEvent pCallbackFunction, TickType_t xTimeout, TickType_t xIdentifier )
+ {
+ size_t lLength = strlen( pcHostName );
+ DNSCallback_t *pxCallback = ( DNSCallback_t * )pvPortMalloc( sizeof( *pxCallback ) + lLength );
+
+ /* Translate from ms to number of clock ticks. */
+ xTimeout /= portTICK_PERIOD_MS;
+ if( pxCallback != NULL )
+ {
+ if( listLIST_IS_EMPTY( &xCallbackList ) )
+ {
+ /* This is the first one, start the DNS timer to check for timeouts */
+ vIPReloadDNSTimer( FreeRTOS_min_uint32( 1000U, xTimeout ) );
+ }
+ strcpy( pxCallback->pcName, pcHostName );
+ pxCallback->pCallbackFunction = pCallbackFunction;
+ pxCallback->pvSearchID = pvSearchID;
+ pxCallback->xRemaningTime = xTimeout;
+ vTaskSetTimeOutState( &pxCallback->xTimeoutState );
+ listSET_LIST_ITEM_OWNER( &( pxCallback->xListItem ), ( void* ) pxCallback );
+ listSET_LIST_ITEM_VALUE( &( pxCallback->xListItem ), xIdentifier );
+ vTaskSuspendAll();
+ {
+ vListInsertEnd( &xCallbackList, &pxCallback->xListItem );
+ }
+ xTaskResumeAll();
+ }
+ }
+ /*-----------------------------------------------------------*/
+
+ /* A DNS reply was received, see if there is any matching entry and
+ call the handler. */
+ static void vDNSDoCallback( TickType_t xIdentifier, const char *pcName, uint32_t ulIPAddress );
+ static void vDNSDoCallback( TickType_t xIdentifier, const char *pcName, uint32_t ulIPAddress )
+ {
+ const ListItem_t *pxIterator;
+ const MiniListItem_t* xEnd = ( const MiniListItem_t* )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 ) == xIdentifier )
+ {
+ DNSCallback_t *pxCallback = ( DNSCallback_t * ) listGET_LIST_ITEM_OWNER( pxIterator );
+ pxCallback->pCallbackFunction( pcName, pxCallback->pvSearchID, ulIPAddress );
+ uxListRemove( &pxCallback->xListItem );
+ vPortFree( pxCallback );
+ if( listLIST_IS_EMPTY( &xCallbackList ) )
+ {
+ vIPSetDnsTimerEnableState( pdFALSE );
+ }
+ break;
+ }
+ }
+ }
+ xTaskResumeAll();
+ }
+
+#endif /* ipconfigDNS_USE_CALLBACKS != 0 */
+/*-----------------------------------------------------------*/
+
+#if( ipconfigDNS_USE_CALLBACKS == 0 )
+uint32_t FreeRTOS_gethostbyname( const char *pcHostName )
+#else
+uint32_t FreeRTOS_gethostbyname_a( const char *pcHostName, FOnDNSEvent pCallback, void *pvSearchID, TickType_t xTimeout )
+#endif
+{
+uint32_t ulIPAddress = 0UL;
+TickType_t xReadTimeOut_ms = ipconfigSOCK_DEFAULT_RECEIVE_BLOCK_TIME;
+TickType_t xIdentifier = 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 != 0 )
+ {
+ 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( 0 == ulIPAddress )
+ {
+ xIdentifier = ( TickType_t )ipconfigRAND32( );
+ }
+
+ #if( ipconfigDNS_USE_CALLBACKS != 0 )
+ {
+ if( pCallback != NULL )
+ {
+ if( ulIPAddress == 0UL )
+ {
+ /* The user has provided a callback function, so do not block on recvfrom() */
+ if( 0 != xIdentifier )
+ {
+ xReadTimeOut_ms = 0;
+ vDNSSetCallBack( pcHostName, pvSearchID, pCallback, xTimeout, ( TickType_t )xIdentifier );
+ }
+ }
+ else
+ {
+ /* The IP address is known, do the call-back now. */
+ pCallback( pcHostName, pvSearchID, ulIPAddress );
+ }
+ }
+ }
+ #endif
+
+ if( ( ulIPAddress == 0UL ) && ( 0 != xIdentifier ) )
+ {
+ ulIPAddress = prvGetHostByName( pcHostName, xIdentifier, xReadTimeOut_ms );
+ }
+
+ return ulIPAddress;
+}
+/*-----------------------------------------------------------*/
+
+static uint32_t prvGetHostByName( const char *pcHostName, TickType_t xIdentifier, TickType_t xReadTimeOut_ms )
+{
+struct freertos_sockaddr xAddress;
+Socket_t xDNSSocket;
+uint32_t ulIPAddress = 0UL;
+uint8_t *pucUDPPayloadBuffer;
+uint32_t ulAddressLength = sizeof( struct freertos_sockaddr );
+BaseType_t xAttempt;
+int32_t lBytes;
+size_t xPayloadLength, xExpectedPayloadLength;
+TickType_t xWriteTimeOut_ms = ipconfigSOCK_DEFAULT_SEND_BLOCK_TIME;
+
+#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; 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. */
+ xExpectedPayloadLength = sizeof( DNSMessage_t ) + strlen( pcHostName ) + sizeof( uint16_t ) + sizeof( uint16_t ) + 2u;
+
+ xDNSSocket = prvCreateDNSSocket();
+
+ if( xDNSSocket != NULL )
+ {
+ FreeRTOS_setsockopt( xDNSSocket, 0, FREERTOS_SO_SNDTIMEO, ( void * ) &xWriteTimeOut_ms, sizeof( TickType_t ) );
+ FreeRTOS_setsockopt( xDNSSocket, 0, FREERTOS_SO_RCVTIMEO, ( void * ) &xReadTimeOut_ms, sizeof( TickType_t ) );
+
+ for( xAttempt = 0; xAttempt < ipconfigDNS_REQUEST_ATTEMPTS; xAttempt++ )
+ {
+ /* 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. */
+ pucUDPPayloadBuffer = ( uint8_t * ) FreeRTOS_GetUDPPayloadBuffer( xExpectedPayloadLength, portMAX_DELAY );
+
+ if( pucUDPPayloadBuffer != NULL )
+ {
+ /* Create the message in the obtained buffer. */
+ xPayloadLength = prvCreateDNSMessage( pucUDPPayloadBuffer, pcHostName, xIdentifier );
+
+ 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. */
+ ( ( DNSMessage_t * ) pucUDPPayloadBuffer) -> usFlags = 0;
+ xAddress.sin_addr = ipLLMNR_IP_ADDR; /* Is in network byte order. */
+ xAddress.sin_port = FreeRTOS_ntohs( ipLLMNR_PORT );
+ }
+ else
+#endif
+ {
+ /* Use DNS server. */
+ xAddress.sin_addr = ulIPAddress;
+ xAddress.sin_port = dnsDNS_PORT;
+ }
+
+ ulIPAddress = 0UL;
+
+ if( FreeRTOS_sendto( xDNSSocket, pucUDPPayloadBuffer, xPayloadLength, FREERTOS_ZERO_COPY, &xAddress, sizeof( xAddress ) ) != 0 )
+ {
+ /* Wait for the reply. */
+ lBytes = FreeRTOS_recvfrom( xDNSSocket, &pucUDPPayloadBuffer, 0, FREERTOS_ZERO_COPY, &xAddress, &ulAddressLength );
+
+ if( lBytes > 0 )
+ {
+ /* The reply was received. Process it. */
+ ulIPAddress = prvParseDNSReply( pucUDPPayloadBuffer, lBytes, xIdentifier );
+
+ /* Finished with the buffer. The zero copy interface
+ is being used, so the buffer must be freed by the
+ task. */
+ FreeRTOS_ReleaseUDPPayloadBuffer( ( void * ) pucUDPPayloadBuffer );
+
+ if( ulIPAddress != 0UL )
+ {
+ /* All done. */
+ break;
+ }
+ }
+ }
+ else
+ {
+ /* The message was not sent so the stack will not be
+ releasing the zero copy - it must be released here. */
+ FreeRTOS_ReleaseUDPPayloadBuffer( ( void * ) pucUDPPayloadBuffer );
+ }
+ }
+ }
+
+ /* Finished with the socket. */
+ FreeRTOS_closesocket( xDNSSocket );
+ }
+
+ return ulIPAddress;
+}
+/*-----------------------------------------------------------*/
+
+static size_t prvCreateDNSMessage( uint8_t *pucUDPPayloadBuffer, const char *pcHostName, TickType_t xIdentifier )
+{
+DNSMessage_t *pxDNSMessageHeader;
+uint8_t *pucStart, *pucByte;
+DNSTail_t *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. */
+};
+
+ /* Copy in the const part of the header. */
+ memcpy( ( void * ) pucUDPPayloadBuffer, ( void * ) &xDefaultPartDNSHeader, sizeof( xDefaultPartDNSHeader ) );
+
+ /* Write in a unique identifier. */
+ pxDNSMessageHeader = ( DNSMessage_t * ) pucUDPPayloadBuffer;
+ pxDNSMessageHeader->usIdentifier = ( uint16_t ) xIdentifier;
+
+ /* Create the resource record at the end of the header. First
+ find the end of the header. */
+ pucStart = pucUDPPayloadBuffer + sizeof( xDefaultPartDNSHeader );
+
+ /* Leave a gap for the first length bytes. */
+ pucByte = pucStart + 1;
+
+ /* Copy in the host name. */
+ strcpy( ( char * ) pucByte, pcHostName );
+
+ /* Mark the end of the string. */
+ pucByte += strlen( pcHostName );
+ *pucByte = 0x00u;
+
+ /* Walk 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. */
+ pucByte = pucStart;
+
+ do
+ {
+ pucByte++;
+
+ while( ( *pucByte != 0x00 ) && ( *pucByte != '.' ) )
+ {
+ pucByte++;
+ }
+
+ /* Fill in the byte count, then move the pucStart pointer up to
+ the found byte position. */
+ *pucStart = ( uint8_t ) ( ( uint32_t ) pucByte - ( uint32_t ) pucStart );
+ ( *pucStart )--;
+
+ pucStart = pucByte;
+
+ } while( *pucByte != 0x00 );
+
+ /* Finish off the record. */
+
+ pxTail = (DNSTail_t *)( pucByte + 1 );
+
+ vSetField16( pxTail, DNSTail_t, usType, dnsTYPE_A_HOST ); /* Type A: host */
+ vSetField16( pxTail, DNSTail_t, usClass, dnsCLASS_IN ); /* 1: Class IN */
+
+ /* Return the total size of the generated message, which is the space from
+ the last written byte to the beginning of the buffer. */
+ return ( ( uint32_t ) pucByte - ( uint32_t ) pucUDPPayloadBuffer + 1 ) + sizeof( *pxTail );
+}
+/*-----------------------------------------------------------*/
+
+#if( ipconfigUSE_DNS_CACHE == 1 )
+
+ static uint8_t *prvReadNameField( uint8_t *pucByte, size_t xSourceLen, char *pcName, size_t xDestLen )
+ {
+ size_t xNameLen = 0;
+ BaseType_t xCount;
+
+ if( 0 == xSourceLen )
+ {
+ return NULL;
+ }
+
+ /* Determine if the name is the fully coded name, or an offset to the name
+ elsewhere in the message. */
+ if( ( *pucByte & dnsNAME_IS_OFFSET ) == dnsNAME_IS_OFFSET )
+ {
+ /* Jump over the two byte offset. */
+ if( xSourceLen > sizeof( uint16_t ) )
+ {
+ pucByte += sizeof( uint16_t );
+ }
+ else
+ {
+ pucByte = NULL;
+ }
+ }
+ else
+ {
+ /* pucByte points to the full name. Walk over the string. */
+ while( ( NULL != pucByte ) && ( *pucByte != 0x00 ) && ( xSourceLen > 1 ) )
+ {
+ /* If this is not the first time through the loop, then add a
+ separator in the output. */
+ if( ( xNameLen > 0 ) && ( xNameLen < ( xDestLen - 1 ) ) )
+ {
+ pcName[ xNameLen++ ] = '.';
+ }
+
+ /* Process the first/next sub-string. */
+ for( xCount = *(pucByte++), xSourceLen--;
+ xCount-- && xSourceLen > 1;
+ pucByte++, xSourceLen-- )
+ {
+ if( xNameLen < xDestLen - 1 )
+ {
+ pcName[ xNameLen++ ] = *( ( char * )pucByte );
+ }
+ else
+ {
+ /* DNS name is too big for the provided buffer. */
+ pucByte = NULL;
+ break;
+ }
+ }
+ }
+
+ /* Confirm that a fully formed name was found. */
+ if( NULL != pucByte )
+ {
+ if( 0x00 == *pucByte )
+ {
+ pucByte++;
+ xSourceLen--;
+ pcName[ xNameLen++ ] = '\0';
+ }
+ else
+ {
+ pucByte = NULL;
+ }
+ }
+ }
+
+ return pucByte;
+ }
+#endif /* ipconfigUSE_DNS_CACHE == 1 */
+/*-----------------------------------------------------------*/
+
+static uint8_t *prvSkipNameField( uint8_t *pucByte, size_t xSourceLen )
+{
+ size_t xChunkLength;
+
+ if( 0 == xSourceLen )
+ {
+ return NULL;
+ }
+
+ /* Determine if the name is the fully coded name, or an offset to the name
+ elsewhere in the message. */
+ if( ( *pucByte & dnsNAME_IS_OFFSET ) == dnsNAME_IS_OFFSET )
+ {
+ /* Jump over the two byte offset. */
+ if( xSourceLen > sizeof( uint16_t ) )
+ {
+ pucByte += sizeof( uint16_t );
+ }
+ else
+ {
+ pucByte = NULL;
+ }
+ }
+ else
+ {
+ /* pucByte points to the full name. Walk over the string. */
+ while( ( *pucByte != 0x00 ) && ( xSourceLen > 1 ) )
+ {
+ xChunkLength = *pucByte + 1;
+
+ if( xSourceLen > xChunkLength )
+ {
+ xSourceLen -= xChunkLength;
+ pucByte += xChunkLength;
+ }
+ else
+ {
+ pucByte = NULL;
+ break;
+ }
+ }
+
+ /* Confirm that a fully formed name was found. */
+ if( NULL != pucByte )
+ {
+ if( 0x00 == *pucByte )
+ {
+ pucByte++;
+ }
+ else
+ {
+ pucByte = NULL;
+ }
+ }
+ }
+
+ return pucByte;
+}
+/*-----------------------------------------------------------*/
+
+uint32_t ulDNSHandlePacket( NetworkBufferDescriptor_t *pxNetworkBuffer )
+{
+DNSMessage_t *pxDNSMessageHeader;
+
+ if( pxNetworkBuffer->xDataLength >= sizeof( DNSMessage_t ) )
+ {
+ pxDNSMessageHeader =
+ ( DNSMessage_t * )( pxNetworkBuffer->pucEthernetBuffer + sizeof( UDPPacket_t ) );
+
+ prvParseDNSReply( ( uint8_t * )pxDNSMessageHeader,
+ pxNetworkBuffer->xDataLength,
+ ( uint32_t )pxDNSMessageHeader->usIdentifier );
+ }
+
+ /* The packet was not consumed. */
+ return pdFAIL;
+}
+/*-----------------------------------------------------------*/
+
+#if( ipconfigUSE_NBNS == 1 )
+
+ uint32_t ulNBNSHandlePacket (NetworkBufferDescriptor_t *pxNetworkBuffer )
+ {
+ UDPPacket_t *pxUDPPacket = ( UDPPacket_t * ) pxNetworkBuffer->pucEthernetBuffer;
+ uint8_t *pucUDPPayloadBuffer = pxNetworkBuffer->pucEthernetBuffer + sizeof( UDPPacket_t );
+
+ /* The network buffer data length has already been set to the
+ length of the UDP payload. */
+ prvTreatNBNS( pucUDPPayloadBuffer,
+ pxNetworkBuffer->xDataLength,
+ pxUDPPacket->xIPHeader.ulSourceIPAddress );
+
+ /* The packet was not consumed. */
+ return pdFAIL;
+ }
+
+#endif /* ipconfigUSE_NBNS */
+/*-----------------------------------------------------------*/
+
+static uint32_t prvParseDNSReply( uint8_t *pucUDPPayloadBuffer, size_t xBufferLength, TickType_t xIdentifier )
+{
+DNSMessage_t *pxDNSMessageHeader;
+DNSAnswerRecord_t *pxDNSAnswerRecord;
+uint32_t ulIPAddress = 0UL;
+#if( ipconfigUSE_LLMNR == 1 )
+ char *pcRequestedName = NULL;
+#endif
+uint8_t *pucByte;
+size_t xSourceBytesRemaining;
+uint16_t x, usDataLength, usQuestions;
+#if( ipconfigUSE_LLMNR == 1 )
+ uint16_t usType = 0, usClass = 0;
+#endif
+#if( ipconfigUSE_DNS_CACHE == 1 )
+ char pcName[ ipconfigDNS_CACHE_NAME_LENGTH ] = "";
+#endif
+
+ /* Ensure that the buffer is of at least minimal DNS message length. */
+ if( xBufferLength < sizeof( DNSMessage_t ) )
+ {
+ return dnsPARSE_ERROR;
+ }
+ else
+ {
+ xSourceBytesRemaining = xBufferLength;
+ }
+
+ /* Parse the DNS message header. */
+ pxDNSMessageHeader = ( DNSMessage_t * ) pucUDPPayloadBuffer;
+
+ if( pxDNSMessageHeader->usIdentifier == ( uint16_t ) xIdentifier )
+ {
+ /* Start at the first byte after the header. */
+ pucByte = pucUDPPayloadBuffer + sizeof( DNSMessage_t );
+ xSourceBytesRemaining -= sizeof( DNSMessage_t );
+
+ /* Skip any question records. */
+ usQuestions = FreeRTOS_ntohs( pxDNSMessageHeader->usQuestions );
+ for( x = 0; x < usQuestions; x++ )
+ {
+ #if( ipconfigUSE_LLMNR == 1 )
+ {
+ if( x == 0 )
+ {
+ pcRequestedName = ( char * ) pucByte;
+ }
+ }
+ #endif
+
+#if( ipconfigUSE_DNS_CACHE == 1 )
+ if( x == 0 )
+ {
+ pucByte = prvReadNameField( pucByte,
+ xSourceBytesRemaining,
+ pcName,
+ sizeof( pcName ) );
+
+ /* Check for a malformed response. */
+ if( NULL == pucByte )
+ {
+ return dnsPARSE_ERROR;
+ }
+ else
+ {
+ xSourceBytesRemaining = ( pucUDPPayloadBuffer + xBufferLength ) - pucByte;
+ }
+ }
+ else
+#endif /* ipconfigUSE_DNS_CACHE */
+ {
+ /* Skip the variable length pcName field. */
+ pucByte = prvSkipNameField( pucByte,
+ xSourceBytesRemaining );
+
+ /* Check for a malformed response. */
+ if( NULL == pucByte )
+ {
+ return dnsPARSE_ERROR;
+ }
+ else
+ {
+ xSourceBytesRemaining = pucUDPPayloadBuffer + xBufferLength - pucByte;
+ }
+ }
+
+ /* Check the remaining buffer size. */
+ if( xSourceBytesRemaining >= 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 += sizeof( uint32_t );
+ xSourceBytesRemaining -= sizeof( uint32_t );
+ }
+ else
+ {
+ /* Malformed response. */
+ return dnsPARSE_ERROR;
+ }
+ }
+
+ /* Search through the answer records. */
+ pxDNSMessageHeader->usAnswers = FreeRTOS_ntohs( pxDNSMessageHeader->usAnswers );
+
+ if( ( pxDNSMessageHeader->usFlags & dnsRX_FLAGS_MASK ) == dnsEXPECTED_RX_FLAGS )
+ {
+ for( x = 0; x < pxDNSMessageHeader->usAnswers; x++ )
+ {
+ pucByte = prvSkipNameField( pucByte,
+ xSourceBytesRemaining );
+
+ /* Check for a malformed response. */
+ if( NULL == pucByte )
+ {
+ return dnsPARSE_ERROR;
+ }
+ else
+ {
+ xSourceBytesRemaining = pucUDPPayloadBuffer + xBufferLength - pucByte;
+ }
+
+ /* Is there enough data for an IPv4 A record answer and, if so,
+ is this an A record? */
+ if( xSourceBytesRemaining >= sizeof( DNSAnswerRecord_t ) + sizeof( uint32_t ) &&
+ usChar2u16( pucByte ) == dnsTYPE_A_HOST )
+ {
+ /* This is the required record type and is of sufficient size. */
+ pxDNSAnswerRecord = ( DNSAnswerRecord_t * )pucByte;
+
+ /* Sanity check the data length of an IPv4 answer. */
+ if( FreeRTOS_ntohs( pxDNSAnswerRecord->usDataLength ) == sizeof( uint32_t ) )
+ {
+ /* Copy the IP address out of the record. */
+ memcpy( &ulIPAddress,
+ pucByte + sizeof( DNSAnswerRecord_t ),
+ sizeof( uint32_t ) );
+
+ #if( ipconfigUSE_DNS_CACHE == 1 )
+ {
+ prvProcessDNSCache( pcName, &ulIPAddress, pxDNSAnswerRecord->ulTTL, pdFALSE );
+ }
+ #endif /* ipconfigUSE_DNS_CACHE */
+ #if( ipconfigDNS_USE_CALLBACKS != 0 )
+ {
+ /* See if any asynchronous call was made to FreeRTOS_gethostbyname_a() */
+ vDNSDoCallback( ( TickType_t ) pxDNSMessageHeader->usIdentifier, pcName, ulIPAddress );
+ }
+ #endif /* ipconfigDNS_USE_CALLBACKS != 0 */
+ }
+
+ pucByte += sizeof( DNSAnswerRecord_t ) + sizeof( uint32_t );
+ xSourceBytesRemaining -= ( sizeof( DNSAnswerRecord_t ) + sizeof( uint32_t ) );
+ break;
+ }
+ else if( xSourceBytesRemaining >= sizeof( DNSAnswerRecord_t ) )
+ {
+ /* It's not an A record, so skip it. Get the header location
+ and then jump over the header. */
+ pxDNSAnswerRecord = ( DNSAnswerRecord_t * )pucByte;
+ pucByte += sizeof( DNSAnswerRecord_t );
+ xSourceBytesRemaining -= sizeof( DNSAnswerRecord_t );
+
+ /* Determine the length of the answer data from the header. */
+ usDataLength = FreeRTOS_ntohs( pxDNSAnswerRecord->usDataLength );
+
+ /* Jump over the answer. */
+ if( xSourceBytesRemaining >= usDataLength )
+ {
+ pucByte += usDataLength;
+ xSourceBytesRemaining -= usDataLength;
+ }
+ else
+ {
+ /* Malformed response. */
+ return dnsPARSE_ERROR;
+ }
+ }
+ }
+ }
+#if( ipconfigUSE_LLMNR == 1 )
+ else if( usQuestions && ( usType == dnsTYPE_A_HOST ) && ( usClass == dnsCLASS_IN ) )
+ {
+ /* If this is not a reply to our DNS request, it might an LLMNR
+ request. */
+ if( xApplicationDNSQueryHook ( ( pcRequestedName + 1 ) ) )
+ {
+ int16_t usLength;
+ NetworkBufferDescriptor_t *pxNewBuffer = NULL;
+ NetworkBufferDescriptor_t *pxNetworkBuffer = pxUDPPayloadBuffer_to_NetworkBuffer( pucUDPPayloadBuffer );
+ LLMNRAnswer_t *pxAnswer;
+
+ if( ( xBufferAllocFixedSize == pdFALSE ) && ( pxNetworkBuffer != NULL ) )
+ {
+ BaseType_t xDataLength = xBufferLength + sizeof( UDPHeader_t ) + sizeof( EthernetHeader_t ) + sizeof( IPHeader_t );
+
+ /* The field xDataLength was set to the length of the UDP payload.
+ The answer (reply) will be longer than the request, so the packet
+ must be duplicaed into a bigger buffer */
+ pxNetworkBuffer->xDataLength = xDataLength;
+ pxNewBuffer = pxDuplicateNetworkBufferWithDescriptor( pxNetworkBuffer, xDataLength + 16 );
+ if( pxNewBuffer != NULL )
+ {
+ BaseType_t xOffset1, xOffset2;
+
+ xOffset1 = ( BaseType_t ) ( pucByte - pucUDPPayloadBuffer );
+ xOffset2 = ( BaseType_t ) ( ( ( uint8_t * ) pcRequestedName ) - pucUDPPayloadBuffer );
+
+ pxNetworkBuffer = pxNewBuffer;
+ pucUDPPayloadBuffer = pxNetworkBuffer->pucEthernetBuffer + ipUDP_PAYLOAD_OFFSET_IPv4;
+
+ pucByte = pucUDPPayloadBuffer + xOffset1;
+ pcRequestedName = ( char * ) ( pucUDPPayloadBuffer + xOffset2 );
+ pxDNSMessageHeader = ( DNSMessage_t * ) pucUDPPayloadBuffer;
+
+ }
+ else
+ {
+ /* Just to indicate that the message may not be answered. */
+ pxNetworkBuffer = NULL;
+ }
+ }
+ if( pxNetworkBuffer != NULL )
+ {
+ pxAnswer = (LLMNRAnswer_t *)pucByte;
+
+ /* We leave 'usIdentifier' and 'usQuestions' untouched */
+ 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 */
+
+ pxAnswer->ucNameCode = dnsNAME_IS_OFFSET;
+ pxAnswer->ucNameOffset = ( uint8_t )( pcRequestedName - ( char * ) pucUDPPayloadBuffer );
+
+ 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 ) );
+
+ usLength = ( int16_t ) ( sizeof( *pxAnswer ) + ( size_t ) ( pucByte - pucUDPPayloadBuffer ) );
+
+ prvReplyDNSMessage( pxNetworkBuffer, usLength );
+
+ if( pxNewBuffer != NULL )
+ {
+ vReleaseNetworkBufferAndDescriptor( pxNewBuffer );
+ }
+ }
+ }
+ }
+#endif /* ipconfigUSE_LLMNR == 1 */
+ }
+
+ return ulIPAddress;
+}
+/*-----------------------------------------------------------*/
+
+#if( ipconfigUSE_NBNS == 1 )
+
+ static void prvTreatNBNS( uint8_t *pucUDPPayloadBuffer, size_t xBufferLength, uint32_t ulIPAddress )
+ {
+ uint16_t usFlags, usType, usClass;
+ uint8_t *pucSource, *pucTarget;
+ uint8_t ucByte;
+ uint8_t ucNBNSName[ 17 ];
+
+ /* Check for minimum buffer size. */
+ if( xBufferLength < sizeof( NBNSRequest_t ) )
+ {
+ 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 ) - 2;
+ pucTarget[ 1 ] = '\0';
+
+ /* Start with decoding the last 2 bytes. */
+ pucSource = pucUDPPayloadBuffer + ( offsetof( NBNSRequest_t, ucName ) + ( dnsNBNS_ENCODED_NAME_LENGTH - 2 ) );
+
+ for( ;; )
+ {
+ ucByte = ( uint8_t ) ( ( ( pucSource[ 0 ] - 0x41 ) << 4 ) | ( pucSource[ 1 ] - 0x41 ) );
+
+ /* Make sure there are no trailing spaces in the name. */
+ if( ( ucByte == ' ' ) && ( pucTarget[ 1 ] == '\0' ) )
+ {
+ ucByte = '\0';
+ }
+
+ *pucTarget = ucByte;
+
+ if( pucTarget == ucNBNSName )
+ {
+ break;
+ }
+
+ pucTarget -= 1;
+ pucSource -= 2;
+ }
+
+ #if( ipconfigUSE_DNS_CACHE == 1 )
+ {
+ if( ( usFlags & dnsNBNS_FLAGS_RESPONSE ) != 0 )
+ {
+ /* If this is a response from another device,
+ add the name to the DNS cache */
+ prvProcessDNSCache( ( char * ) ucNBNSName, &ulIPAddress, 0, pdFALSE );
+ }
+ }
+ #else
+ {
+ /* Avoid compiler warnings. */
+ ( void ) ulIPAddress;
+ }
+ #endif /* ipconfigUSE_DNS_CACHE */
+
+ if( ( ( usFlags & dnsNBNS_FLAGS_RESPONSE ) == 0 ) &&
+ ( 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. */
+ NetworkBufferDescriptor_t *pxNetworkBuffer = pxUDPPayloadBuffer_to_NetworkBuffer( pucUDPPayloadBuffer );
+
+ if( ( xBufferAllocFixedSize == pdFALSE ) && ( pxNetworkBuffer != NULL ) )
+ {
+ NetworkBufferDescriptor_t *pxNewBuffer;
+ BaseType_t xDataLength = pxNetworkBuffer->xDataLength + sizeof( UDPHeader_t ) +
+ sizeof( EthernetHeader_t ) + sizeof( IPHeader_t );
+
+ /* The field xDataLength was set to the length of the UDP payload.
+ The answer (reply) will be longer than the request, so the packet
+ must be duplicated into a bigger buffer */
+ pxNetworkBuffer->xDataLength = xDataLength;
+ pxNewBuffer = pxDuplicateNetworkBufferWithDescriptor( pxNetworkBuffer, xDataLength + 16 );
+ 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 = (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() */
+ 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 );
+
+ pxAnswer = (NBNSAnswer_t *)( pucUDPPayloadBuffer + offsetof( NBNSRequest_t, usType ) );
+
+ 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 ) );
+
+ usLength = ( uint16_t ) ( offsetof( NBNSRequest_t, usType ) + sizeof( NBNSAnswer_t ) );
+
+ prvReplyDNSMessage( pxNetworkBuffer, usLength );
+ }
+ }
+ }
+ }
+
+#endif /* ipconfigUSE_NBNS */
+/*-----------------------------------------------------------*/
+
+static Socket_t prvCreateDNSSocket( void )
+{
+Socket_t xSocket = NULL;
+struct freertos_sockaddr xAddress;
+BaseType_t xReturn;
+TickType_t xTimeoutTime = pdMS_TO_TICKS( 200 );
+
+ /* 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 );
+
+ /* 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 )
+ {
+ FreeRTOS_closesocket( xSocket );
+ xSocket = NULL;
+ }
+ else
+ {
+ /* Set the send and receive timeouts. */
+ FreeRTOS_setsockopt( xSocket, 0, FREERTOS_SO_RCVTIMEO, ( void * ) &xTimeoutTime, sizeof( TickType_t ) );
+ FreeRTOS_setsockopt( xSocket, 0, FREERTOS_SO_SNDTIMEO, ( void * ) &xTimeoutTime, sizeof( TickType_t ) );
+ }
+
+ return xSocket;
+}
+/*-----------------------------------------------------------*/
+
+#if( ( ipconfigUSE_NBNS == 1 ) || ( ipconfigUSE_LLMNR == 1 ) )
+
+ static void prvReplyDNSMessage( NetworkBufferDescriptor_t *pxNetworkBuffer, BaseType_t lNetLength )
+ {
+ UDPPacket_t *pxUDPPacket;
+ IPHeader_t *pxIPHeader;
+ UDPHeader_t *pxUDPHeader;
+
+ pxUDPPacket = (UDPPacket_t *) pxNetworkBuffer->pucEthernetBuffer;
+ pxIPHeader = &pxUDPPacket->xIPHeader;
+ pxUDPHeader = &pxUDPPacket->xUDPHeader;
+ /* HT: started using defines like 'ipSIZE_OF_xxx' */
+ pxIPHeader->usLength = FreeRTOS_htons( 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( lNetLength + ipSIZE_OF_UDP_HEADER );
+ vFlip_16( pxUDPPacket->xUDPHeader.usSourcePort, pxUDPPacket->xUDPHeader.usDestinationPort );
+
+ /* Important: tell NIC driver how many bytes must be sent */
+ pxNetworkBuffer->xDataLength = ( 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 = 0x00;
+ pxIPHeader->usHeaderChecksum = usGenerateChecksum( 0UL, ( uint8_t * ) &( pxIPHeader->ucVersionHeaderLength ), ipSIZE_OF_IPv4_HEADER );
+ pxIPHeader->usHeaderChecksum = ~FreeRTOS_htons( pxIPHeader->usHeaderChecksum );
+
+ /* calculate the UDP checksum for outgoing package */
+ usGenerateProtocolChecksum( ( uint8_t* ) pxUDPPacket, pxNetworkBuffer->xDataLength, pdTRUE );
+ }
+ #endif
+
+ /* 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 )
+
+ static void 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 ) / 1000;
+ static BaseType_t xFreeEntry = 0;
+ configASSERT(pcName);
+
+
+ /* For each entry in the DNS cache table. */
+ for( x = 0; x < ipconfigDNS_CACHE_ENTRIES; x++ )
+ {
+ if( xDNSCache[ x ].pcName[ 0 ] == 0 )
+ {
+ continue;
+ }
+
+ if( 0 == strcmp( xDNSCache[ x ].pcName, pcName ) )
+ {
+ /* 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 ) ) )
+ {
+ *pulIP = xDNSCache[ x ].ulIPAddress;
+ }
+ else
+ {
+ /* Age out the old cached record. */
+ xDNSCache[ x ].pcName[ 0 ] = 0;
+ }
+ }
+ else
+ {
+ xDNSCache[ x ].ulIPAddress = *pulIP;
+ xDNSCache[ x ].ulTTL = ulTTL;
+ xDNSCache[ x ].ulTimeWhenAddedInSeconds = ulCurrentTimeSeconds;
+ }
+
+ xFound = pdTRUE;
+ break;
+ }
+ }
+
+ if( xFound == pdFALSE )
+ {
+ if( xLookUp != pdFALSE )
+ {
+ *pulIP = 0;
+ }
+ else
+ {
+ /* Add or update the item. */
+ if( strlen( pcName ) < ipconfigDNS_CACHE_NAME_LENGTH )
+ {
+ strcpy( xDNSCache[ xFreeEntry ].pcName, pcName );
+
+ xDNSCache[ xFreeEntry ].ulIPAddress = *pulIP;
+ xDNSCache[ xFreeEntry ].ulTTL = ulTTL;
+ xDNSCache[ xFreeEntry ].ulTimeWhenAddedInSeconds = ulCurrentTimeSeconds;
+
+ xFreeEntry++;
+ if( xFreeEntry == ipconfigDNS_CACHE_ENTRIES )
+ {
+ xFreeEntry = 0;
+ }
+ }
+ }
+ }
+
+ if( ( xLookUp == 0 ) || ( *pulIP != 0 ) )
+ {
+ FreeRTOS_debug_printf( ( "prvProcessDNSCache: %s: '%s' @ %lxip\n", xLookUp ? "look-up" : "add", pcName, FreeRTOS_ntohl( *pulIP ) ) );
+ }
+ }
+
+#endif /* ipconfigUSE_DNS_CACHE */
+
+#endif /* ipconfigUSE_DNS != 0 */
+
+/*-----------------------------------------------------------*/
+
+/* Provide access to private members for testing. */
+#ifdef AMAZON_FREERTOS_ENABLE_UNIT_TESTS
+ #include "iot_freertos_tcp_test_access_dns_define.h"
+#endif
+
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