blob: 9c71aa9460ee9601b83dac9e2d50af3633f360ae [file] [log] [blame]
/*
* FreeRTOS+TCP V2.0.0
* Copyright (C) 2017 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. If you wish to use our Amazon
* FreeRTOS name, please do so in a fair use way that does not cause confusion.
*
* 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://www.FreeRTOS.org
* http://aws.amazon.com/freertos
*
* 1 tab == 4 spaces!
*/
/* 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 0x3500u
#define dnsONE_QUESTION 0x0100u
#define dnsOUTGOING_FLAGS 0x0001u /* Standard query. */
#define dnsRX_FLAGS_MASK 0x0f80u /* The bits of interest in the flags field of incoming DNS messages. */
#define dnsEXPECTED_RX_FLAGS 0x0080u /* Should be a response, without any errors. */
#else
#define dnsDNS_PORT 0x0035u
#define dnsONE_QUESTION 0x0001u
#define dnsOUTGOING_FLAGS 0x0100u /* Standard query. */
#define dnsRX_FLAGS_MASK 0x800fu /* The bits of interest in the flags field of incoming DNS messages. */
#define dnsEXPECTED_RX_FLAGS 0x8000u /* 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 0x8000u
#define dnsNBNS_FLAGS_OPCODE_MASK 0x7800u
#define dnsNBNS_FLAGS_OPCODE_QUERY 0x0000u
#define dnsNBNS_FLAGS_OPCODE_REGISTRATION 0x2800u
/* Host types. */
#define dnsTYPE_A_HOST 0x0001u
#define dnsCLASS_IN 0x0001u
/* LLMNR constants. */
#define dnsLLMNR_TTL_VALUE 300000u
#define dnsLLMNR_FLAGS_IS_REPONSE 0x8000u
/* NBNS constants. */
#define dnsNBNS_TTL_VALUE 3600u /* 1 hour valid */
#define dnsNBNS_TYPE_NET_BIOS 0x0020u
#define dnsNBNS_CLASS_IN 0x0001u
#define dnsNBNS_NAME_FLAGS 0x6000u
#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 0x8500u
/*
* 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 );
/*
* Process a response packet from a DNS server.
*/
static uint32_t prvParseDNSReply( uint8_t *pucUDPPayloadBuffer, 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, uint32_t ulIPAddress );
#endif /* ipconfigUSE_NBNS */
#if( ipconfigUSE_DNS_CACHE == 1 )
static uint8_t *prvReadNameField( uint8_t *pucByte, char *pcName, BaseType_t xLen );
static void prvProcessDNSCache( const char *pcName, uint32_t *pulIP, 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 */
uint8_t ucAge; /* A value that is periodically decremented but can also be refreshed by active communication. The ARP cache entry is removed if the value reaches zero. */
} DNSCacheRow_t;
static DNSCacheRow_t xDNSCache[ ipconfigDNS_CACHE_ENTRIES ];
#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;
#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, 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;
static uint16_t usIdentifier = 0u;
TickType_t xReadTimeOut_ms = 1200U;
/* Generate a unique identifier for this query. Keep it in a local variable
as gethostbyname() may be called from different threads */
TickType_t xIdentifier = ( TickType_t )usIdentifier++;
/* If a DNS cache is used then check the cache before issuing another DNS
request. */
#if( ipconfigUSE_DNS_CACHE == 1 )
{
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 */
#if( ipconfigDNS_USE_CALLBACKS != 0 )
{
if( pCallback != NULL )
{
if( ulIPAddress == 0UL )
{
/* The user has provided a callback function, so do not block on recvfrom() */
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)
{
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;
static uint32_t ulAddressLength;
BaseType_t xAttempt;
int32_t lBytes;
size_t xPayloadLength, xExpectedPayloadLength;
TickType_t xWriteTimeOut_ms = 100U;
#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, 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, char *pcName, BaseType_t xLen )
{
BaseType_t xNameLen = 0;
/* 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. */
pucByte += sizeof( uint16_t );
}
else
{
/* pucByte points to the full name. Walk over the string. */
while( *pucByte != 0x00 )
{
BaseType_t xCount;
if( xNameLen && xNameLen < xLen - 1 )
pcName[xNameLen++] = '.';
for( xCount = *(pucByte++); xCount--; pucByte++ )
{
if( xNameLen < xLen - 1 )
pcName[xNameLen++] = *( ( char * ) pucByte );
}
}
pucByte++;
}
return pucByte;
}
#endif /* ipconfigUSE_DNS_CACHE == 1 */
/*-----------------------------------------------------------*/
static uint8_t *prvSkipNameField( uint8_t *pucByte )
{
/* 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. */
pucByte += sizeof( uint16_t );
}
else
{
/* pucByte points to the full name. Walk over the string. */
while( *pucByte != 0x00 )
{
/* The number of bytes to jump for each name section is stored in the byte
before the name section. */
pucByte += ( *pucByte + 1 );
}
pucByte++;
}
return pucByte;
}
/*-----------------------------------------------------------*/
uint32_t ulDNSHandlePacket( NetworkBufferDescriptor_t *pxNetworkBuffer )
{
uint8_t *pucUDPPayloadBuffer = pxNetworkBuffer->pucEthernetBuffer + sizeof( UDPPacket_t );
DNSMessage_t *pxDNSMessageHeader = ( DNSMessage_t * ) pucUDPPayloadBuffer;
prvParseDNSReply( pucUDPPayloadBuffer, ( 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( *pxUDPPacket );
prvTreatNBNS( pucUDPPayloadBuffer, pxUDPPacket->xIPHeader.ulSourceIPAddress );
/* The packet was not consumed. */
return pdFAIL;
}
#endif /* ipconfigUSE_NBNS */
/*-----------------------------------------------------------*/
static uint32_t prvParseDNSReply( uint8_t *pucUDPPayloadBuffer, TickType_t xIdentifier )
{
DNSMessage_t *pxDNSMessageHeader;
uint32_t ulIPAddress = 0UL;
#if( ipconfigUSE_LLMNR == 1 )
char *pcRequestedName = NULL;
#endif
uint8_t *pucByte;
uint16_t x, usDataLength, usQuestions;
#if( ipconfigUSE_LLMNR == 1 )
uint16_t usType = 0, usClass = 0;
#endif
#if( ipconfigUSE_DNS_CACHE == 1 )
char pcName[128] = ""; /*_RB_ What is the significance of 128? Probably too big to go on the stack for a small MCU but don't know how else it could be made re-entrant. Might be necessary. */
#endif
pxDNSMessageHeader = ( DNSMessage_t * ) pucUDPPayloadBuffer;
if( pxDNSMessageHeader->usIdentifier == ( uint16_t ) xIdentifier )
{
/* Start at the first byte after the header. */
pucByte = pucUDPPayloadBuffer + 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, pcName, sizeof( pcName ) );
}
else
#endif /* ipconfigUSE_DNS_CACHE */
{
/* Skip the variable length pcName field. */
pucByte = prvSkipNameField( pucByte );
}
#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 );
}
/* Search through the answers 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 );
/* Is the type field that of an A record? */
if( usChar2u16( pucByte ) == dnsTYPE_A_HOST )
{
/* This is the required record. Skip the type, class, and
time to live fields, plus the first byte of the data
length. */
pucByte += ( sizeof( uint32_t ) + sizeof( uint32_t ) + sizeof( uint8_t ) );
/* Sanity check the data length. */
if( ( size_t ) *pucByte == sizeof( uint32_t ) )
{
/* Skip the second byte of the length. */
pucByte++;
/* Copy the IP address out of the record. */
memcpy( ( void * ) &ulIPAddress, ( void * ) pucByte, sizeof( uint32_t ) );
#if( ipconfigUSE_DNS_CACHE == 1 )
{
prvProcessDNSCache( pcName, &ulIPAddress, 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 */
}
break;
}
else
{
/* Skip the type, class and time to live fields. */
pucByte += ( sizeof( uint32_t ) + sizeof( uint32_t ) );
/* Determine the length of the data in the field. */
memcpy( ( void * ) &usDataLength, ( void * ) pucByte, sizeof( uint16_t ) );
usDataLength = FreeRTOS_ntohs( usDataLength );
/* Jump over the data length bytes, and the data itself. */
pucByte += usDataLength + sizeof( uint16_t );
}
}
}
#if( ipconfigUSE_LLMNR == 1 )
else if( ( usQuestions != ( uint16_t )0u ) && ( usType == ( uint16_t )dnsTYPE_A_HOST ) && ( usClass == ( uint16_t )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 = 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 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;
/* 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, uint32_t ulIPAddress )
{
uint16_t usFlags, usType, usClass;
uint8_t *pucSource, *pucTarget;
uint8_t ucByte;
uint8_t ucNBNSName[ 17 ];
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, 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 )
{
static 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 );
#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, pdTRUE );
}
#endif
/* 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 );
/* 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, BaseType_t xLookUp )
{
BaseType_t x;
BaseType_t xFound = pdFALSE;
static BaseType_t xFreeEntry = 0;
/* For each entry in the DNS cache table. */
for( x = 0; x < ipconfigDNS_CACHE_ENTRIES; x++ )
{
if( xDNSCache[ x ].pcName[ 0 ] == 0 )
{
break;
}
if( strncmp( xDNSCache[ x ].pcName, pcName, sizeof( xDNSCache[ x ].pcName ) ) == 0 )
{
/* Is this function called for a lookup or to add/update an IP address? */
if( xLookUp != pdFALSE )
{
*pulIP = xDNSCache[ x ].ulIPAddress;
}
else
{
xDNSCache[ x ].ulIPAddress = *pulIP;
}
xFound = pdTRUE;
break;
}
}
if( xFound == pdFALSE )
{
if( xLookUp != pdFALSE )
{
*pulIP = 0;
}
else
{
/* Called to add or update an item */
strncpy( xDNSCache[ xFreeEntry ].pcName, pcName, sizeof( xDNSCache[ xFreeEntry ].pcName ) );
xDNSCache[ xFreeEntry ].ulIPAddress = *pulIP;
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 */