static void prvSimpleZeroCopyUDPClientTask( void *pvParameters )
{
xSocket_t xClientSocket;
uint8_t *pucUDPPayloadBuffer;
struct freertos_sockaddr xDestinationAddress;
portBASE_TYPE lReturned;
uint32_t ulCount = 0UL, ulIPAddress;
const uint32_t ulLoopsPerSocket = 10UL;
const uint8_t *pucStringToSend = ( const uint8_t * ) "Server received (using zero copy): Message number ";
const portTickType x150ms = 150UL / portTICK_RATE_MS;
/* 15 is added to ensure the number, \r\n and terminating zero fit. */
const size_t xStringLength = strlen( ( char * ) pucStringToSend ) + 15;
/* Remove compiler warning about unused parameters. */
( void ) pvParameters;
/* It is assumed that this task is not created until the network is up,
so the IP address can be obtained immediately. store the IP address being
used in ulIPAddress. This is done so the socket can send to a different
port on the same IP address. */
FreeRTOS_GetAddressConfiguration( &ulIPAddress, NULL, NULL, NULL );
/* This test sends to itself, so data sent from here is received by a server
socket on the same IP address. Setup the freertos_sockaddr structure with
this nodes IP address, and the port number being sent to. The strange
casting is to try and remove compiler warnings on 32 bit machines. */
xDestinationAddress.sin_addr = ulIPAddress;
xDestinationAddress.sin_port = ( uint16_t ) ( ( uint32_t ) pvParameters ) & 0xffffUL;
xDestinationAddress.sin_port = FreeRTOS_htons( xDestinationAddress.sin_port );
for( ;; )
{
/* Create the socket. */
xClientSocket = FreeRTOS_socket( FREERTOS_AF_INET, FREERTOS_SOCK_DGRAM, FREERTOS_IPPROTO_UDP );
configASSERT( xClientSocket != FREERTOS_INVALID_SOCKET );
/* The count is used to differentiate between different messages sent to
the server, and to break out of the do while loop below. */
ulCount = 0UL;
do
{
/* This task is going to send using the zero copy interface. The
data being sent is therefore written directly into a buffer that is
passed into, rather than copied into, the FreeRTOS_sendto()
function.
First obtain a buffer of adequate length from the IP stack into which
the string will be written. Although a max delay is used, the actual
delay will be capped to ipconfigMAX_SEND_BLOCK_TIME_TICKS, hence
the do while loop is used to ensure a buffer is obtained. */
do
{
} while( ( pucUDPPayloadBuffer = ( uint8_t * ) FreeRTOS_GetUDPPayloadBuffer( xStringLength, portMAX_DELAY ) ) == NULL );
/* A buffer was successfully obtained. Create the string that is
sent to the server. First the string is filled with zeros as this will
effectively be the null terminator when the string is received at the other
end. Note that the string is being written directly into the buffer
obtained from the IP stack above. */
memset( ( void * ) pucUDPPayloadBuffer, 0x00, xStringLength );
sprintf( ( char * ) pucUDPPayloadBuffer, "%s%lu\r\n", ( char * ) pucStringToSend, ulCount );
/* Pass the buffer into the send function. ulFlags has the
FREERTOS_ZERO_COPY bit set so the IP stack will take control of the
buffer rather than copy data out of the buffer. */
lReturned = FreeRTOS_sendto( xClientSocket, /* The socket being sent to. */
( void * ) pucUDPPayloadBuffer, /* A pointer to the the data being sent. */
strlen( ( const char * ) pucUDPPayloadBuffer ) + 1, /* The length of the data being sent - including the string's null terminator. */
FREERTOS_ZERO_COPY, /* ulFlags with the FREERTOS_ZERO_COPY bit set. */
&xDestinationAddress, /* Where the data is being sent. */
sizeof( xDestinationAddress ) );
if( lReturned == 0 )
{
/* The send operation failed, so this task is still responsible
for the buffer obtained from the IP stack. To ensure the buffer
is not lost it must either be used again, or, as in this case,
returned to the IP stack using FreeRTOS_ReleaseUDPPayloadBuffer().
pucUDPPayloadBuffer can be safely re-used after this call. */
FreeRTOS_ReleaseUDPPayloadBuffer( ( void * ) pucUDPPayloadBuffer );
}
else
{
/* The send was successful so the IP stack is now managing the
buffer pointed to by pucUDPPayloadBuffer, and the IP stack will
return the buffer once it has been sent. pucUDPPayloadBuffer can
be safely re-used. */
}
ulCount++;
} while( ( lReturned != FREERTOS_SOCKET_ERROR ) && ( ulCount < ulLoopsPerSocket ) );
FreeRTOS_closesocket( xClientSocket );
/* A short delay to prevent the messages scrolling off the screen too
quickly. */
vTaskDelay( x150ms );
}
}
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 void prvZeroCopyEchoClientTask( void *pvParameters )
{
xSocket_t xSocket;
struct freertos_sockaddr xEchoServerAddress;
static char cTxString[ 40 ];
int32_t lLoopCount = 0UL;
volatile uint32_t ulRxCount = 0UL, ulTxCount = 0UL;
uint32_t xAddressLength = sizeof( xEchoServerAddress );
int32_t lReturned;
uint8_t *pucUDPPayloadBuffer;
const int32_t lMaxLoopCount = 50;
const char * const pcStringToSend = "Zero copy message number";
/* The buffer is large enough to hold the string, a number, and the string terminator. */
const size_t xBufferLength = strlen( pcStringToSend ) + 15;
#if ipconfigINCLUDE_EXAMPLE_FREERTOS_PLUS_TRACE_CALLS == 1
{
/* When the trace recorder code is included user events are generated to
mark the sending and receiving of the echoed data (only in the zero copy
task). */
xZeroCopySendEvent = xTraceOpenLabel( "ZeroCopyTx" );
xZeroCopyReceiveEvent = xTraceOpenLabel( "ZeroCopyRx" );
}
#endif /* ipconfigINCLUDE_EXAMPLE_FREERTOS_PLUS_TRACE_CALLS */
/* Remove compiler warning about unused parameters. */
( void ) pvParameters;
/* Delay for a little while to ensure the task is out of synch with the
other echo task implemented above. */
vTaskDelay( echoLOOP_DELAY >> 1 );
/* Echo requests are sent to the echo server. The address of the echo
server is configured by the constants configECHO_SERVER_ADDR0 to
configECHO_SERVER_ADDR3 in FreeRTOSConfig.h. */
xEchoServerAddress.sin_port = FreeRTOS_htons( echoECHO_PORT );
xEchoServerAddress.sin_addr = FreeRTOS_inet_addr_quick( configECHO_SERVER_ADDR0,
configECHO_SERVER_ADDR1,
configECHO_SERVER_ADDR2,
configECHO_SERVER_ADDR3 );
for( ;; )
{
/* Create a socket. */
xSocket = FreeRTOS_socket( FREERTOS_AF_INET, FREERTOS_SOCK_DGRAM, FREERTOS_IPPROTO_UDP );
configASSERT( xSocket != FREERTOS_INVALID_SOCKET );
/* Set a time out so a missing reply does not cause the task to block
indefinitely. */
FreeRTOS_setsockopt( xSocket, 0, FREERTOS_SO_RCVTIMEO, &xReceiveTimeOut, sizeof( xReceiveTimeOut ) );
/* Send a number of echo requests. */
for( lLoopCount = 0; lLoopCount < lMaxLoopCount; lLoopCount++ )
{
/* This task is going to send using the zero copy interface. The
data being sent is therefore written directly into a buffer that is
passed by reference into the FreeRTOS_sendto() function. First
obtain a buffer of adequate size from the IP stack. Although a max
delay is used, the actual delay will be capped to
ipconfigMAX_SEND_BLOCK_TIME_TICKS, hence the test to ensure a buffer
was actually obtained. */
pucUDPPayloadBuffer = ( uint8_t * ) FreeRTOS_GetUDPPayloadBuffer( xBufferLength, portMAX_DELAY );
if( pucUDPPayloadBuffer != NULL )
{
/* A buffer was successfully obtained. Create the string that is
sent to the echo server. Note the string is written directly
into the buffer obtained from the IP stack. */
sprintf( ( char * ) pucUDPPayloadBuffer, "%s %u\r\n", "Zero copy message number", ( unsigned int ) ulTxCount );
/* Also copy the string into a local buffer so it can be compared
with the string that is later received back from the echo server. */
strcpy( cTxString, ( char * ) pucUDPPayloadBuffer );
/* Pass the buffer into the send function. ulFlags has the
FREERTOS_ZERO_COPY bit set so the IP stack will take control of
the buffer, rather than copy data out of the buffer. */
echoMARK_SEND_IN_TRACE_BUFFER( xZeroCopySendEvent );
lReturned = FreeRTOS_sendto( xSocket, /* The socket being sent to. */
( void * ) pucUDPPayloadBuffer, /* The buffer being passed into the IP stack. */
strlen( cTxString ) + 1, /* The length of the data being sent. Plus 1 to ensure the null terminator is part of the data. */
FREERTOS_ZERO_COPY, /* ulFlags with the zero copy bit is set. */
&xEchoServerAddress, /* Where the data is being sent. */
sizeof( xEchoServerAddress ) );
if( lReturned == 0 )
{
/* The send operation failed, so this task is still
responsible for the buffer obtained from the IP stack. To
ensure the buffer is not lost it must either be used again,
or, as in this case, returned to the IP stack using
FreeRTOS_ReleaseUDPPayloadBuffer(). pucUDPPayloadBuffer can
be safely re-used to receive from the socket below once the
buffer has been returned to the stack. */
FreeRTOS_ReleaseUDPPayloadBuffer( ( void * ) pucUDPPayloadBuffer );
}
else
{
/* The send was successful so the IP stack is now managing
the buffer pointed to by pucUDPPayloadBuffer, and the IP
stack will return the buffer once it has been sent.
pucUDPPayloadBuffer can be safely re-used to receive from
the socket below. */
}
/* Keep a count of how many echo requests have been transmitted
so it can be compared to the number of echo replies received.
It would be expected to loose at least one to an ARP message the
first time the connection is created. */
ulTxCount++;
/* Receive data on the socket. ulFlags has the zero copy bit set
(FREERTOS_ZERO_COPY) indicating to the stack that a reference to
the received data should be passed out to this task using the
second parameter to the FreeRTOS_recvfrom() call. When this is
done the IP stack is no longer responsible for releasing the
buffer, and the task *must* return the buffer to the stack when
it is no longer needed. By default the receive block time is
portMAX_DELAY. */
echoMARK_SEND_IN_TRACE_BUFFER( xZeroCopyReceiveEvent );
lReturned = FreeRTOS_recvfrom( xSocket, /* The socket to receive from. */
( void * ) &pucUDPPayloadBuffer, /* pucUDPPayloadBuffer will be set to point to the buffer that already contains the received data. */
0, /* Ignored because the zero copy interface is being used. */
FREERTOS_ZERO_COPY, /* ulFlags with the FREERTOS_ZERO_COPY bit set. */
&xEchoServerAddress, /* The address from which the data was sent. */
&xAddressLength );
if( lReturned > 0 )
{
/* Compare the string sent to the echo server with the string
received back from the echo server. */
if( strcmp( ( char * ) pucUDPPayloadBuffer, cTxString ) == 0 )
{
/* The strings matched. */
ulRxCount++;
}
/* The buffer that contains the data passed out of the stack
*must* be returned to the stack. */
FreeRTOS_ReleaseUDPPayloadBuffer( pucUDPPayloadBuffer );
}
}
}
/* Pause for a short while to ensure the network is not too
congested. */
vTaskDelay( echoLOOP_DELAY );
/* Close this socket before looping back to create another. */
FreeRTOS_closesocket( xSocket );
}
}
uint32_t FreeRTOS_gethostbyname( const uint8_t *pcHostName )
{
static uint16_t usIdentifier = 0;
struct freertos_sockaddr xAddress;
static xSocket_t xDNSSocket = NULL;
uint32_t ulIPAddress = 0UL;
uint8_t *pucUDPPayloadBuffer;
static uint32_t ulAddressLength;
portBASE_TYPE xAttempt;
int32_t lBytes;
size_t xPayloadLength;
const size_t xExpectedPayloadLength = sizeof( xDNSMessage_t ) + strlen( ( const char * const ) pcHostName ) + sizeof( uint16_t ) + sizeof( uint16_t ) + 2; /* Two for the count of characters in the first subdomain part, and the string end byte */
if( xDNSSocket == NULL )
{
xDNSSocket = prvCreateDNSSocket();
}
if( xDNSSocket != NULL )
{
/* Generate a unique identifier for this query. */
usIdentifier++;
for( xAttempt = 0; xAttempt < dnsMAX_REQUEST_ATTEMPTS; xAttempt++ )
{
/* Get a buffer. This uses a maximum delay, but the delay will be
capped to ipconfigMAX_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, usIdentifier );
iptraceSENDING_DNS_REQUEST();
/* Obtain the DNS server address. */
FreeRTOS_GetAddressConfiguration( NULL, NULL, NULL, &ulIPAddress );
/* Send the DNS message. */
xAddress.sin_addr = ulIPAddress;
xAddress.sin_port = dnsDNS_PORT;
ulIPAddress = 0;
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, usIdentifier );
/* 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 != 0 )
{
/* 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 );
}
}
}
}
return ulIPAddress;
}