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Set MDNS AA bit while answering MDNS request. #1223

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Set MDNS AA bit while answering MDNS request. #1223

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85aef25
Set MDNS AA bit while answering MDNS request.
ActoryOu Feb 4, 2025
0cf31da
Merge branch 'main' into MdnsAABit
tony-josi-aws Feb 7, 2025
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19 changes: 15 additions & 4 deletions source/FreeRTOS_DNS_Parser.c
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Original file line number Diff line number Diff line change
Expand Up @@ -545,11 +545,22 @@
if( ( pxNetworkBuffer != NULL ) )
{
pxAnswer = ( ( LLMNRAnswer_t * ) xSet.pucByte );

/* We leave 'usIdentifier' and 'usQuestions' untouched */
vSetField16( xSet.pxDNSMessageHeader, DNSMessage_t, usFlags, dnsLLMNR_FLAGS_IS_RESPONSE ); /* Set the response flag */
vSetField16( xSet.pxDNSMessageHeader, DNSMessage_t, usAnswers, 1 ); /* Provide a single answer */
vSetField16( xSet.pxDNSMessageHeader, DNSMessage_t, usAuthorityRRs, 0 ); /* No authority */
vSetField16( xSet.pxDNSMessageHeader, DNSMessage_t, usAdditionalRRs, 0 ); /* No additional info */
if( xSet.usPortNumber == ipMDNS_PORT )
{
/* Follow RFC6762 to set QR bit (section 18.2) and authoritative answer (AA) bit (section 18.4). */
vSetField16( xSet.pxDNSMessageHeader, DNSMessage_t, usFlags, dnsMDNS_FLAGS_IS_RESPONSE );
}
else
{
/* Follow RFC4795 to set QR bit (section 2.1.1) */
vSetField16( xSet.pxDNSMessageHeader, DNSMessage_t, usFlags, dnsLLMNR_FLAGS_IS_RESPONSE );
}

vSetField16( xSet.pxDNSMessageHeader, DNSMessage_t, usAnswers, 1 ); /* Provide a single answer */
vSetField16( xSet.pxDNSMessageHeader, DNSMessage_t, usAuthorityRRs, 0 ); /* No authority */
vSetField16( xSet.pxDNSMessageHeader, DNSMessage_t, usAdditionalRRs, 0 ); /* No additional info */

pxAnswer->ucNameCode = dnsNAME_IS_OFFSET;
pxAnswer->ucNameOffset = ( uint8_t ) ( xSet.pcRequestedName - ( char * ) pucNewBuffer );
Expand Down
14 changes: 8 additions & 6 deletions source/include/FreeRTOS_DNS_Globals.h
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Original file line number Diff line number Diff line change
Expand Up @@ -109,12 +109,14 @@
#define ipLLMNR_IP_ADDR 0xFC0000E0UL
#endif /* ipconfigBYTE_ORDER == pdFREERTOS_BIG_ENDIAN */

#define ipMDNS_TIME_TO_LIVE 255U

#define ipLLMNR_PORT 5355U /* Standard LLMNR port. */
#define ipDNS_PORT 53U /* Standard DNS port. */
#define ipNBNS_PORT 137U /* NetBIOS Name Service. */
#define ipNBDGM_PORT 138U /* Datagram Service, not included. */
/* MDNS constants. */
#define ipMDNS_TIME_TO_LIVE 255U
#define dnsMDNS_FLAGS_IS_RESPONSE 0x8400U /**< MDNS flag value for response. */

#define ipLLMNR_PORT 5355U /* Standard LLMNR port. */
#define ipDNS_PORT 53U /* Standard DNS port. */
#define ipNBNS_PORT 137U /* NetBIOS Name Service. */
#define ipNBDGM_PORT 138U /* Datagram Service, not included. */

/** @brief freertos_addrinfo is the equivalent of 'struct addrinfo'. */
struct freertos_addrinfo
Expand Down
111 changes: 97 additions & 14 deletions test/unit-test/FreeRTOS_DNS_Parser/FreeRTOS_DNS_Parser_utest.c
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Expand Up @@ -1776,7 +1776,7 @@ void test_DNS_ParseDNSReply_answer_lmmnr_reply_xBufferAllocFixedsize( void )
uint8_t * pucUDPPayloadBuffer = udp_buffer + prvALIGNED_UDP_PAYLOAD_OFFSET_IPv4;
size_t uxBufferLength = 250;
struct freertos_addrinfo * pxAddressInfo;
uint16_t usPort;
uint16_t usPort = ipLLMNR_PORT;

xBufferAllocFixedSize = pdTRUE;
uint8_t * nullAddress = NULL;
Expand Down Expand Up @@ -1854,7 +1854,7 @@ void test_DNS_ParseDNSReply_answer_lmmnr_reply( void )
uint8_t * pucUDPPayloadBuffer = udp_buffer + prvALIGNED_UDP_PAYLOAD_OFFSET_IPv4;
size_t uxBufferLength = 250;
struct freertos_addrinfo * pxAddressInfo;
uint16_t usPort;
uint16_t usPort = ipLLMNR_PORT;
NetworkEndPoint_t xEndPoint = { 0 };

memset( pucUDPPayloadBuffer, 0x00, uxBufferLength );
Expand Down Expand Up @@ -1927,7 +1927,7 @@ void test_DNS_ParseDNSReply_answer_lmmnr_reply2( void )
uint8_t * pucUDPPayloadBuffer = ( ( uint8_t * ) udp_buffer ) + ipUDP_PAYLOAD_OFFSET_IPv6;
size_t uxBufferLength = 250;
struct freertos_addrinfo * pxAddressInfo;
uint16_t usPort;
uint16_t usPort = ipLLMNR_PORT;
NetworkEndPoint_t xEndPoint = { 0 };

memset( pucUDPPayloadBuffer, 0x00, uxBufferLength );
Expand Down Expand Up @@ -2000,7 +2000,7 @@ void test_DNS_ParseDNSReply_answer_lmmnr_reply3( void )
uint8_t * pucUDPPayloadBuffer = ( ( uint8_t * ) udp_buffer ) + ipUDP_PAYLOAD_OFFSET_IPv4 - 1;
size_t uxBufferLength = 250;
struct freertos_addrinfo * pxAddressInfo;
uint16_t usPort;
uint16_t usPort = ipLLMNR_PORT;
NetworkEndPoint_t xEndPoint = { 0 };

memset( pucUDPPayloadBuffer, 0x00, uxBufferLength );
Expand Down Expand Up @@ -2074,7 +2074,7 @@ void test_DNS_ParseDNSReply_answer_lmmnr_reply_diffUsType( void )
uint8_t * pucUDPPayloadBuffer = ( ( uint8_t * ) udp_buffer ) + ipUDP_PAYLOAD_OFFSET_IPv4;
size_t uxBufferLength = 250;
struct freertos_addrinfo * pxAddressInfo;
uint16_t usPort;
uint16_t usPort = ipLLMNR_PORT;
NetworkEndPoint_t xEndPoint = { 0 };

memset( pucUDPPayloadBuffer, 0x00, uxBufferLength );
Expand Down Expand Up @@ -2151,7 +2151,7 @@ void test_DNS_ParseDNSReply_answer_lmmnr_reply_NullNetworkBuffer( void )
uint8_t * pucUDPPayloadBuffer = ( ( uint8_t * ) udp_buffer ) + ipUDP_PAYLOAD_OFFSET_IPv4;
size_t uxBufferLength = 250;
struct freertos_addrinfo * pxAddressInfo;
uint16_t usPort;
uint16_t usPort = ipLLMNR_PORT;
NetworkEndPoint_t xEndPoint = { 0 };

memset( pucUDPPayloadBuffer, 0x00, uxBufferLength );
Expand Down Expand Up @@ -2228,7 +2228,7 @@ void test_DNS_ParseDNSReply_answer_lmmnr_reply4( void )
uint8_t * pucUDPPayloadBuffer = ( ( uint8_t * ) udp_buffer ) + ipUDP_PAYLOAD_OFFSET_IPv4;
size_t uxBufferLength = 250;
struct freertos_addrinfo * pxAddressInfo;
uint16_t usPort;
uint16_t usPort = ipLLMNR_PORT;

memset( pucUDPPayloadBuffer, 0x00, uxBufferLength );

Expand Down Expand Up @@ -2299,7 +2299,7 @@ void test_DNS_ParseDNSReply_answer_lmmnr_reply5( void )
uint8_t * pucUDPPayloadBuffer = ( ( uint8_t * ) udp_buffer ) + ipUDP_PAYLOAD_OFFSET_IPv4;
size_t uxBufferLength = 250;
struct freertos_addrinfo * pxAddressInfo;
uint16_t usPort;
uint16_t usPort = ipLLMNR_PORT;

memset( pucUDPPayloadBuffer, 0x00, uxBufferLength );

Expand Down Expand Up @@ -2371,7 +2371,7 @@ void test_DNS_ParseDNSReply_answer_lmmnr_reply_query_hook_false( void )
uint8_t * pucUDPPayloadBuffer = ( ( uint8_t * ) udp_buffer ) + ipUDP_PAYLOAD_OFFSET_IPv4;
struct freertos_addrinfo * pxAddressInfo;
struct xNetworkEndPoint xEndPoint = { 0 };
uint16_t usPort;
uint16_t usPort = ipLLMNR_PORT;

memset( pucUDPPayloadBuffer, 0x0, 250 );
size_t uxBufferLength = 250;
Expand Down Expand Up @@ -2443,7 +2443,7 @@ void test_DNS_ParseDNSReply_answer_lmmnr_reply_null_new_netbuffer( void )
uint8_t * pucUDPPayloadBuffer = ( ( uint8_t * ) udp_buffer ) + ipUDP_PAYLOAD_OFFSET_IPv4;
size_t uxBufferLength = 250;
struct freertos_addrinfo * pxAddressInfo;
uint16_t usPort;
uint16_t usPort = ipLLMNR_PORT;
NetworkEndPoint_t xEndPoint = { 0 };

memset( pucUDPPayloadBuffer, 0x00, uxBufferLength );
Expand Down Expand Up @@ -2517,7 +2517,7 @@ void test_DNS_ParseDNSReply_answer_lmmnr_reply_null_new_netbuffer2( void )
uint8_t * pucUDPPayloadBuffer = ( ( uint8_t * ) udp_buffer ) + ipUDP_PAYLOAD_OFFSET_IPv4;
size_t uxBufferLength = 250;
struct freertos_addrinfo * pxAddressInfo;
uint16_t usPort;
uint16_t usPort = ipLLMNR_PORT;
NetworkEndPoint_t xEndPoint = { 0 };

memset( pucUDPPayloadBuffer, 0x00, uxBufferLength );
Expand Down Expand Up @@ -2591,7 +2591,7 @@ void test_DNS_ParseDNSReply_answer_lmmnr_reply_valid_new_netbuffer( void )
uint8_t * pucUDPPayloadBuffer = ( ( uint8_t * ) udp_buffer ) + ipUDP_PAYLOAD_OFFSET_IPv4;
size_t uxBufferLength = 250;
struct freertos_addrinfo * pxAddressInfo;
uint16_t usPort;
uint16_t usPort = ipLLMNR_PORT;
NetworkEndPoint_t xEndPoint = { 0 };

memset( pucUDPPayloadBuffer, 0x00, uxBufferLength );
Expand Down Expand Up @@ -2683,7 +2683,7 @@ void test_DNS_ParseDNSReply_answer_lmmnr_reply_valid_new_netbuffer2( void )
uint8_t * pucUDPPayloadBuffer = ( ( uint8_t * ) udp_buffer ) + ipUDP_PAYLOAD_OFFSET_IPv4;
size_t uxBufferLength = 250;
struct freertos_addrinfo * pxAddressInfo;
uint16_t usPort;
uint16_t usPort = ipLLMNR_PORT;
NetworkEndPoint_t xEndPoint = { 0 };

memset( pucUDPPayloadBuffer, 0x00, uxBufferLength );
Expand Down Expand Up @@ -2775,7 +2775,7 @@ void test_DNS_ParseDNSReply_answer_lmmnr_reply_valid_new_netbuffer3( void )
uint8_t * pucUDPPayloadBuffer = ( ( uint8_t * ) udp_buffer ) + ipUDP_PAYLOAD_OFFSET_IPv4;
size_t uxBufferLength = 250;
struct freertos_addrinfo * pxAddressInfo;
uint16_t usPort;
uint16_t usPort = ipLLMNR_PORT;
NetworkEndPoint_t xEndPoint = { 0 };

memset( pucUDPPayloadBuffer, 0x00, uxBufferLength );
Expand Down Expand Up @@ -2855,6 +2855,89 @@ void test_DNS_ParseDNSReply_answer_lmmnr_reply_valid_new_netbuffer3( void )
ASSERT_DNS_QUERY_HOOK_CALLED();
}

/**
* @brief ensures that the ip set in Setup is passed to the network with
* vReturnEthernetFrame
*/
void test_DNS_ParseDNSReply_prepare_mdns_answer( void )
{
uint32_t ret;
uint8_t udp_buffer[ 250 + ipUDP_PAYLOAD_OFFSET_IPv4 + sizeof( LLMNRAnswer_t ) ] = { 0 };
uint8_t * pucUDPPayloadBuffer = ( ( uint8_t * ) udp_buffer ) + ipUDP_PAYLOAD_OFFSET_IPv4;
struct freertos_addrinfo * pxAddressInfo;
struct xNetworkEndPoint xEndPoint = { 0 };
uint16_t usPort = ipMDNS_PORT;
UDPPacket_t * pxUDPPacket;

memset( pucUDPPayloadBuffer, 0x0, 250 + sizeof( LLMNRAnswer_t ) );
size_t uxBufferLength = 250 + sizeof( LLMNRAnswer_t );

NetworkBufferDescriptor_t pxNetworkBuffer = { 0 };
xEndPoint.ipv4_settings.ulIPAddress = 0xABCD1234;
pxNetworkBuffer.pucEthernetBuffer = udp_buffer;
pxNetworkBuffer.xDataLength = uxBufferLength;
pxNetworkBuffer.pxEndPoint = &xEndPoint;

/* The second network buffer is used to store MDNS answer. */
NetworkBufferDescriptor_t pxNewBuffer;
memcpy( &pxNewBuffer, &pxNetworkBuffer, sizeof( NetworkBufferDescriptor_t ) );
pxNewBuffer.xDataLength = uxBufferLength;
pxNewBuffer.pucEthernetBuffer = udp_buffer;

pxUDPPacket = ( ( UDPPacket_t * ) pxNetworkBuffer.pucEthernetBuffer );
pxUDPPacket->xIPHeader.ulDestinationIPAddress = ipMDNS_IP_ADDRESS;
pxUDPPacket->xUDPHeader.usSourcePort = usPort;
pxUDPPacket->xUDPHeader.usDestinationPort = usPort;

char dns[ 64 ];
memset( dns, 'a', 64 );
dns[ 63 ] = 0;
BaseType_t xExpected = pdFALSE;
size_t beg = sizeof( DNSMessage_t );

DNSMessage_t * dns_header;

dns_header = ( DNSMessage_t * ) pucUDPPayloadBuffer;

dns_header->usQuestions = FreeRTOS_htons( 1 );
dns_header->usAnswers = FreeRTOS_htons( 0 );
dns_header->usFlags = dnsDNS_PORT;

pucUDPPayloadBuffer[ beg ] = 38;
beg++;
strcpy( pucUDPPayloadBuffer + beg, "FreeRTOSbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb" );
beg += 38;
pucUDPPayloadBuffer[ beg ] = '\0';
beg++;

usChar2u16_ExpectAnyArgsAndReturn( dnsTYPE_A_HOST ); /* usType */
usChar2u16_ExpectAnyArgsAndReturn( dnsCLASS_IN ); /* usClass */
pxUDPPayloadBuffer_to_NetworkBuffer_ExpectAnyArgsAndReturn( &pxNetworkBuffer );

hook_return = pdTRUE;

uxIPHeaderSizePacket_IgnoreAndReturn( ipSIZE_OF_IPv4_HEADER );
pxDuplicateNetworkBufferWithDescriptor_ExpectAnyArgsAndReturn( &pxNewBuffer );
usGenerateChecksum_ExpectAnyArgsAndReturn( 555 );
usGenerateProtocolChecksum_ExpectAnyArgsAndReturn( 444 );
vReturnEthernetFrame_Expect( &pxNewBuffer, pdFALSE );
vReleaseNetworkBufferAndDescriptor_Expect( &pxNewBuffer );

ret = DNS_ParseDNSReply( pucUDPPayloadBuffer,
uxBufferLength,
&pxAddressInfo,
xExpected,
usPort );

TEST_ASSERT_EQUAL( 0, ret );
ASSERT_DNS_QUERY_HOOK_CALLED();
TEST_ASSERT_EQUAL( dnsMDNS_FLAGS_IS_RESPONSE, FreeRTOS_ntohs( dns_header->usFlags ) );
TEST_ASSERT_EQUAL( 1, FreeRTOS_ntohs( dns_header->usAnswers ) );
TEST_ASSERT_EQUAL( ipMDNS_TIME_TO_LIVE, pxUDPPacket->xIPHeader.ucTimeToLive );
TEST_ASSERT_EQUAL( ipMDNS_PORT, pxUDPPacket->xUDPHeader.usSourcePort );
TEST_ASSERT_EQUAL( ipMDNS_PORT, pxUDPPacket->xUDPHeader.usDestinationPort );
}

/**
* @brief ensures that when the number of answers is zero no packet is sent over
* the network
Expand Down