/*
* FreeRTOS+TCP <DEVELOPMENT BRANCH>
* Copyright (C) 2022 Amazon.com, Inc. or its affiliates. All Rights Reserved.
*
* SPDX-License-Identifier: MIT
*
* 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
*/
/**
* @file FreeRTOS_TCP_Transmission_IPV6.c
* @brief Module which prepares the packet to be sent through
* a socket for FreeRTOS+TCP.
* It depends on FreeRTOS_TCP_WIN.c, which handles the TCP windowing
* schemes.
*
* Endianness: in this module all ports and IP addresses are stored in
* host byte-order, except fields in the IP-packets
*/
/* Standard includes. */
#include <stdint.h>
#include <stdio.h>
/* FreeRTOS includes. */
#include "FreeRTOS.h"
#include "task.h"
#include "queue.h"
#include "semphr.h"
/* FreeRTOS+TCP includes. */
#include "FreeRTOS_IP.h"
#include "FreeRTOS_Sockets.h"
#include "FreeRTOS_IP_Private.h"
#include "NetworkInterface.h"
#include "NetworkBufferManagement.h"
#include "FreeRTOS_ARP.h"
#include "FreeRTOSIPConfigDefaults.h"
#include "FreeRTOS_ND.h"
#include "FreeRTOS_TCP_IP.h"
#include "FreeRTOS_TCP_Reception.h"
#include "FreeRTOS_TCP_Transmission.h"
#include "FreeRTOS_TCP_State_Handling.h"
#include "FreeRTOS_TCP_Utils.h"
/* Just make sure the contents doesn't get compiled if TCP is not enabled. */
/* *INDENT-OFF* */
#if( ipconfigUSE_IPv6 != 0 ) && ( ipconfigUSE_TCP == 1 )
/* *INDENT-ON* */
/*------------------------------------------------------------------------*/
/**
* @brief Return (or send) a packet to the peer. The data is stored in pxBuffer,
* which may either point to a real network buffer or to a TCP socket field
* called 'xTCP.xPacket'. A temporary xNetworkBuffer will be used to pass
* the data to the NIC.
*
* @param[in] pxSocket The socket owning the connection.
* @param[in] pxDescriptor The network buffer descriptor carrying the packet.
* @param[in] ulLen Length of the packet being sent.
* @param[in] xReleaseAfterSend pdTRUE if the ownership of the descriptor is
* transferred to the network interface.
*/
void prvTCPReturnPacket_IPV6( FreeRTOS_Socket_t * pxSocket,
NetworkBufferDescriptor_t * pxDescriptor,
uint32_t ulLen,
BaseType_t xReleaseAfterSend )
{
TCPPacket_IPv6_t * pxTCPPacket = NULL;
ProtocolHeaders_t * pxProtocolHeaders = NULL;
IPHeader_IPv6_t * pxIPHeader = NULL;
BaseType_t xDoRelease = xReleaseAfterSend;
EthernetHeader_t * pxEthernetHeader = NULL;
NetworkBufferDescriptor_t * pxNetworkBuffer = pxDescriptor;
NetworkBufferDescriptor_t xTempBuffer;
/* memcpy() helper variables for MISRA Rule 21.15 compliance*/
MACAddress_t xMACAddress;
const void * pvCopySource = NULL;
void * pvCopyDest = NULL;
const size_t uxIPHeaderSize = ipSIZE_OF_IPv6_HEADER;
IPv6_Address_t xDestinationIPAddress;
do
{
/* Use do/while to be able to break out of the flow */
if( ( pxNetworkBuffer == NULL ) && ( pxSocket == NULL ) )
{
/* Either 'pxNetworkBuffer' or 'pxSocket' should be defined. */
break;
}
/* For sending, a pseudo network buffer will be used, as explained above. */
if( pxNetworkBuffer == NULL )
{
pxNetworkBuffer = &xTempBuffer;
( void ) memset( &xTempBuffer, 0, sizeof( xTempBuffer ) );
#if ( ipconfigUSE_LINKED_RX_MESSAGES != 0 )
{
pxNetworkBuffer->pxNextBuffer = NULL;
}
#endif
pxNetworkBuffer->pucEthernetBuffer = pxSocket->u.xTCP.xPacket.u.ucLastPacket;
pxNetworkBuffer->xDataLength = sizeof( pxSocket->u.xTCP.xPacket.u.ucLastPacket );
xDoRelease = pdFALSE;
}
#if ( ipconfigZERO_COPY_TX_DRIVER != 0 )
{
if( xDoRelease == pdFALSE )
{
/* A zero-copy network driver wants to pass the packet buffer
* to DMA, so a new buffer must be created. */
pxNetworkBuffer = pxDuplicateNetworkBufferWithDescriptor( pxNetworkBuffer, ( size_t ) pxNetworkBuffer->xDataLength );
if( pxNetworkBuffer != NULL )
{
xDoRelease = pdTRUE;
}
else
{
FreeRTOS_debug_printf( ( "prvTCPReturnPacket: duplicate failed\n" ) );
}
}
}
#endif /* ipconfigZERO_COPY_TX_DRIVER */
configASSERT( pxNetworkBuffer->pucEthernetBuffer != NULL );
/* MISRA Ref 11.3.1 [Misaligned access] */
/* More details at: https://github.com/FreeRTOS/FreeRTOS-Plus-TCP/blob/main/MISRA.md#rule-113 */
/* coverity[misra_c_2012_rule_11_3_violation] */
pxIPHeader = ( ( IPHeader_IPv6_t * ) &( pxNetworkBuffer->pucEthernetBuffer[ ipSIZE_OF_ETH_HEADER ] ) );
#ifndef __COVERITY__
if( pxNetworkBuffer != NULL ) /* LCOV_EXCL_BR_LINE the 2nd branch will never be reached */
#endif
{
/* Map the Ethernet buffer onto a TCPPacket_t struct for easy access to the fields. */
/* MISRA Ref 11.3.1 [Misaligned access] */
/* More details at: https://github.com/FreeRTOS/FreeRTOS-Plus-TCP/blob/main/MISRA.md#rule-113 */
/* coverity[misra_c_2012_rule_11_3_violation] */
pxTCPPacket = ( TCPPacket_IPv6_t * ) pxNetworkBuffer->pucEthernetBuffer;
pxEthernetHeader = ( EthernetHeader_t * ) &( pxTCPPacket->xEthernetHeader );
/* MISRA Ref 11.3.1 [Misaligned access] */
/* More details at: https://github.com/FreeRTOS/FreeRTOS-Plus-TCP/blob/main/MISRA.md#rule-113 */
/* coverity[misra_c_2012_rule_11_3_violation] */
pxProtocolHeaders = ( ProtocolHeaders_t * ) &( pxNetworkBuffer->pucEthernetBuffer[ ipSIZE_OF_ETH_HEADER + uxIPHeaderSize ] );
if( pxNetworkBuffer->pxEndPoint == NULL )
{
prvTCPReturn_SetEndPoint( pxSocket, pxNetworkBuffer, uxIPHeaderSize );
if( pxNetworkBuffer->pxEndPoint == NULL )
{
if( xDoRelease != pdFALSE )
{
vReleaseNetworkBufferAndDescriptor( pxNetworkBuffer );
}
pxNetworkBuffer = NULL;
break;
}
}
/* Fill the packet, swapping from- and to-addresses. */
if( pxSocket != NULL )
{
prvTCPReturn_CheckTCPWindow( pxSocket, pxNetworkBuffer, uxIPHeaderSize );
prvTCPReturn_SetSequenceNumber( pxSocket, pxNetworkBuffer, uxIPHeaderSize, ulLen );
( void ) memcpy( pxIPHeader->xDestinationAddress.ucBytes, pxSocket->u.xTCP.xRemoteIP.xIP_IPv6.ucBytes, ipSIZE_OF_IPv6_ADDRESS );
( void ) memcpy( pxIPHeader->xSourceAddress.ucBytes, pxNetworkBuffer->pxEndPoint->ipv6_settings.xIPAddress.ucBytes, ipSIZE_OF_IPv6_ADDRESS );
}
else
{
IPv6_Address_t xTempAddress;
/* Sending data without a socket, probably replying with a RST flag
* Just swap the two sequence numbers. */
vFlip_32( pxProtocolHeaders->xTCPHeader.ulSequenceNumber, pxProtocolHeaders->xTCPHeader.ulAckNr );
( void ) memcpy( xTempAddress.ucBytes, pxIPHeader->xDestinationAddress.ucBytes, ipSIZE_OF_IPv6_ADDRESS );
( void ) memcpy( pxIPHeader->xDestinationAddress.ucBytes, pxIPHeader->xSourceAddress.ucBytes, ipSIZE_OF_IPv6_ADDRESS );
( void ) memcpy( pxIPHeader->xSourceAddress.ucBytes, xTempAddress.ucBytes, ipSIZE_OF_IPv6_ADDRESS );
}
/* In IPv6, the "payload length" does not include the size of the IP-header */
pxIPHeader->usPayloadLength = FreeRTOS_htons( ulLen - sizeof( IPHeader_IPv6_t ) );
#if ( ipconfigDRIVER_INCLUDED_TX_IP_CHECKSUM == 0 )
{
/* calculate the TCP checksum for an outgoing packet. */
uint32_t ulTotalLength = ulLen + ipSIZE_OF_ETH_HEADER;
( void ) usGenerateProtocolChecksum( ( uint8_t * ) pxNetworkBuffer->pucEthernetBuffer, ulTotalLength, pdTRUE );
}
#endif /* ipconfigDRIVER_INCLUDED_TX_IP_CHECKSUM == 0 */
vFlip_16( pxProtocolHeaders->xTCPHeader.usSourcePort, pxProtocolHeaders->xTCPHeader.usDestinationPort );
/* Important: tell NIC driver how many bytes must be sent. */
pxNetworkBuffer->xDataLength = ( size_t ) ulLen;
pxNetworkBuffer->xDataLength += ipSIZE_OF_ETH_HEADER;
#if ( ipconfigUSE_LINKED_RX_MESSAGES != 0 )
{
pxNetworkBuffer->pxNextBuffer = NULL;
}
#endif
( void ) memcpy( xDestinationIPAddress.ucBytes, pxIPHeader->xDestinationAddress.ucBytes, ipSIZE_OF_IPv6_ADDRESS );
eARPLookupResult_t eResult;
eResult = eNDGetCacheEntry( &xDestinationIPAddress, &xMACAddress, &( pxNetworkBuffer->pxEndPoint ) );
if( eResult == eARPCacheHit )
{
pvCopySource = &xMACAddress;
}
else
{
pvCopySource = &pxEthernetHeader->xSourceAddress;
}
/* Fill in the destination MAC addresses. */
pvCopyDest = &pxEthernetHeader->xDestinationAddress;
( void ) memcpy( pvCopyDest, pvCopySource, sizeof( pxEthernetHeader->xDestinationAddress ) );
/*
* Use helper variables for memcpy() to remain
* compliant with MISRA Rule 21.15. These should be
* optimized away.
*/
/* The source MAC addresses is fixed to 'ipLOCAL_MAC_ADDRESS'. */
pvCopySource = pxNetworkBuffer->pxEndPoint->xMACAddress.ucBytes;
pvCopyDest = &pxEthernetHeader->xSourceAddress;
( void ) memcpy( pvCopyDest, pvCopySource, ( size_t ) ipMAC_ADDRESS_LENGTH_BYTES );
#if ( ipconfigETHERNET_MINIMUM_PACKET_BYTES > 0 )
{
if( pxNetworkBuffer->xDataLength < ( size_t ) ipconfigETHERNET_MINIMUM_PACKET_BYTES )
{
BaseType_t xIndex;
for( xIndex = ( BaseType_t ) pxNetworkBuffer->xDataLength; xIndex < ( BaseType_t ) ipconfigETHERNET_MINIMUM_PACKET_BYTES; xIndex++ )
{
pxNetworkBuffer->pucEthernetBuffer[ xIndex ] = 0U;
}
pxNetworkBuffer->xDataLength = ( size_t ) ipconfigETHERNET_MINIMUM_PACKET_BYTES;
}
}
#endif /* if( ipconfigETHERNET_MINIMUM_PACKET_BYTES > 0 ) */
/* Send! */
iptraceNETWORK_INTERFACE_OUTPUT( pxNetworkBuffer->xDataLength, pxNetworkBuffer->pucEthernetBuffer );
configASSERT( pxNetworkBuffer->pxEndPoint->pxNetworkInterface != NULL );
configASSERT( pxNetworkBuffer->pxEndPoint->pxNetworkInterface->pfOutput != NULL );
NetworkInterface_t * pxInterface = pxNetworkBuffer->pxEndPoint->pxNetworkInterface;
( void ) pxInterface->pfOutput( pxInterface, pxNetworkBuffer, xDoRelease );
if( xDoRelease == pdFALSE )
{
/* Swap-back some fields, as pxBuffer probably points to a socket field
* containing the packet header. */
vFlip_16( pxTCPPacket->xTCPHeader.usSourcePort, pxTCPPacket->xTCPHeader.usDestinationPort );
( void ) memcpy( pxIPHeader->xSourceAddress.ucBytes, pxIPHeader->xDestinationAddress.ucBytes, ipSIZE_OF_IPv6_ADDRESS );
}
else
{
/* Nothing to do: the buffer has been passed to DMA and will be released after use */
}
} /* if( pxNetworkBuffer != NULL ) */
} while( ipFALSE_BOOL );
}
/*-----------------------------------------------------------*/
/**
* @brief Let ARP look-up the MAC-address of the peer and initialise the first SYN
* packet.
*
* @param[in] pxSocket The socket owning the TCP connection. The first packet shall
* be created in this socket.
*
* @return pdTRUE: if the packet was successfully created and the first SYN can be sent.
* Else pdFALSE.
*
* @note Connecting sockets have a special state: eCONNECT_SYN. In this phase,
* the Ethernet address of the target will be found using ARP. In case the
* target IP address is not within the netmask, the hardware address of the
* gateway will be used.
*/
BaseType_t prvTCPPrepareConnect_IPV6( FreeRTOS_Socket_t * pxSocket )
{
TCPPacket_IPv6_t * pxTCPPacket = NULL;
IPHeader_IPv6_t * pxIPHeader = NULL;
eARPLookupResult_t eReturned;
IP_Address_t xRemoteIP;
MACAddress_t xEthAddress;
BaseType_t xReturn = pdTRUE;
uint32_t ulInitialSequenceNumber = 0;
ProtocolHeaders_t * pxProtocolHeaders = NULL;
NetworkEndPoint_t * pxEndPoint = NULL;
#if ( ipconfigHAS_PRINTF != 0 )
{
/* Only necessary for nicer logging. */
( void ) memset( xEthAddress.ucBytes, 0, sizeof( xEthAddress.ucBytes ) );
}
#endif /* ipconfigHAS_PRINTF != 0 */
( void ) memset( xRemoteIP.xIP_IPv6.ucBytes, 0, ipSIZE_OF_IPv6_ADDRESS );
( void ) memcpy( xRemoteIP.xIP_IPv6.ucBytes, pxSocket->u.xTCP.xRemoteIP.xIP_IPv6.ucBytes, ipSIZE_OF_IPv6_ADDRESS );
eReturned = eNDGetCacheEntry( &( xRemoteIP.xIP_IPv6 ), &( xEthAddress ), &( pxEndPoint ) );
FreeRTOS_printf( ( "eNDGetCacheEntry: %d with end-point %p\n", eReturned, ( void * ) pxEndPoint ) );
if( pxEndPoint != NULL )
{
pxSocket->pxEndPoint = pxEndPoint;
}
/* MISRA Ref 11.3.1 [Misaligned access] */
/* More details at: https://github.com/FreeRTOS/FreeRTOS-Plus-TCP/blob/main/MISRA.md#rule-113 */
/* coverity[misra_c_2012_rule_11_3_violation] */
pxProtocolHeaders = ( ( ProtocolHeaders_t * )
&( pxSocket->u.xTCP.xPacket.u.ucLastPacket[ ipSIZE_OF_ETH_HEADER + uxIPHeaderSizeSocket( pxSocket ) ] ) );
switch( eReturned )
{
case eARPCacheHit: /* An ARP table lookup found a valid entry. */
break; /* We can now prepare the SYN packet. */
case eARPCacheMiss: /* An ARP table lookup did not find a valid entry. */
case eCantSendPacket: /* There is no IP address, or an ARP is still in progress. */
default:
/* Count the number of times it could not find the ARP address. */
pxSocket->u.xTCP.ucRepCount++;
FreeRTOS_printf( ( "Looking up %pip with%s end-point\n", ( void * ) xRemoteIP.xIP_IPv6.ucBytes, ( pxEndPoint != NULL ) ? "" : "out" ) );
if( pxEndPoint != NULL )
{
size_t uxNeededSize;
NetworkBufferDescriptor_t * pxNetworkBuffer;
uxNeededSize = ipSIZE_OF_ETH_HEADER + ipSIZE_OF_IPv6_HEADER + sizeof( ICMPHeader_IPv6_t );
pxNetworkBuffer = pxGetNetworkBufferWithDescriptor( uxNeededSize, 0U );
if( pxNetworkBuffer != NULL )
{
pxNetworkBuffer->pxEndPoint = pxEndPoint;
vNDSendNeighbourSolicitation( pxNetworkBuffer, &( xRemoteIP.xIP_IPv6 ) );
}
}
xReturn = pdFALSE;
break;
}
if( xReturn != pdFALSE )
{
/* Get a difficult-to-predict initial sequence number for this 4-tuple. */
ulInitialSequenceNumber = ulApplicationGetNextSequenceNumber( pxSocket->xLocalAddress.ulIP_IPv4,
pxSocket->usLocalPort,
pxSocket->u.xTCP.xRemoteIP.ulIP_IPv4,
pxSocket->u.xTCP.usRemotePort );
/* Check for a random number generation error. */
if( ulInitialSequenceNumber == 0U )
{
xReturn = pdFALSE;
}
}
if( xReturn != pdFALSE )
{
/* The MAC-address of the peer (or gateway) has been found,
* now prepare the initial TCP packet and some fields in the socket. Map
* the buffer onto the TCPPacket_IPv6_t struct to easily access it's field. */
/* MISRA Ref 11.3.1 [Misaligned access] */
/* More details at: https://github.com/FreeRTOS/FreeRTOS-Plus-TCP/blob/main/MISRA.md#rule-113 */
/* coverity[misra_c_2012_rule_11_3_violation] */
pxTCPPacket = ( ( TCPPacket_IPv6_t * ) pxSocket->u.xTCP.xPacket.u.ucLastPacket );
pxIPHeader = &( pxTCPPacket->xIPHeader );
/* reset the retry counter to zero. */
pxSocket->u.xTCP.ucRepCount = 0U;
/* And remember that the connect/SYN data are prepared. */
pxSocket->u.xTCP.bits.bConnPrepared = pdTRUE_UNSIGNED;
/* Now that the Ethernet address is known, the initial packet can be
* prepared. */
( void ) memset( pxSocket->u.xTCP.xPacket.u.ucLastPacket, 0, sizeof( pxSocket->u.xTCP.xPacket.u.ucLastPacket ) );
/* Write the Ethernet address in Source, because it will be swapped by
* prvTCPReturnPacket(). */
( void ) memcpy( ( void * ) ( &( pxTCPPacket->xEthernetHeader.xSourceAddress ) ), ( const void * ) ( &xEthAddress ), sizeof( xEthAddress ) );
if( pxSocket->bits.bIsIPv6 != pdFALSE_UNSIGNED )
{
/* 'ipIPv4_FRAME_TYPE' is already in network-byte-order. */
pxTCPPacket->xEthernetHeader.usFrameType = ipIPv6_FRAME_TYPE;
pxIPHeader->ucVersionTrafficClass = ( uint8_t ) 0x60U;
pxIPHeader->ucTrafficClassFlow = ( uint8_t ) 0x00;
pxIPHeader->usFlowLabel = ( uint16_t ) 0x0000U;
pxIPHeader->usPayloadLength = FreeRTOS_htons( sizeof( TCPHeader_t ) );
pxIPHeader->ucNextHeader = ( uint8_t ) ipPROTOCOL_TCP;
pxIPHeader->ucHopLimit = 128;
/* The Source and Destination addresses will be swapped later. */
( void ) memcpy( pxIPHeader->xSourceAddress.ucBytes, pxSocket->u.xTCP.xRemoteIP.xIP_IPv6.ucBytes, sizeof( pxIPHeader->xSourceAddress.ucBytes ) );
( void ) memcpy( pxIPHeader->xDestinationAddress.ucBytes, pxSocket->xLocalAddress.xIP_IPv6.ucBytes, sizeof( pxIPHeader->xDestinationAddress.ucBytes ) );
pxEndPoint = pxSocket->pxEndPoint;
}
}
if( pxEndPoint != NULL )
{
pxSocket->pxEndPoint = pxEndPoint;
pxProtocolHeaders->xTCPHeader.usSourcePort = FreeRTOS_htons( pxSocket->u.xTCP.usRemotePort );
pxProtocolHeaders->xTCPHeader.usDestinationPort = FreeRTOS_htons( pxSocket->usLocalPort );
/* We are actively connecting, so the peer's Initial Sequence Number (ISN)
* isn't known yet. */
pxSocket->u.xTCP.xTCPWindow.rx.ulCurrentSequenceNumber = 0U;
/* Start with ISN (Initial Sequence Number). */
pxSocket->u.xTCP.xTCPWindow.ulOurSequenceNumber = ulInitialSequenceNumber;
/* The TCP header size is 20 bytes, divided by 4 equals 5, which is put in
* the high nibble of the TCP offset field. */
pxProtocolHeaders->xTCPHeader.ucTCPOffset = 0x50U;
/* Only set the SYN flag. */
pxProtocolHeaders->xTCPHeader.ucTCPFlags = tcpTCP_FLAG_SYN;
/* Set the value of usMSS for this socket. */
prvSocketSetMSS( pxSocket );
/* The initial sequence numbers at our side are known. Later
* vTCPWindowInit() will be called to fill in the peer's sequence numbers, but
* first wait for a SYN+ACK reply. */
prvTCPCreateWindow( pxSocket );
}
else
{
FreeRTOS_printf( ( "prvTCPPrepareConnect: No pxEndPoint yet?\n" ) );
xReturn = pdFAIL;
}
return xReturn;
}
/*-----------------------------------------------------------*/
/**
* @brief Common code for sending a TCP protocol control packet (i.e. no options, no
* payload, just flags).
*
* @param[in] pxNetworkBuffer The network buffer received from the peer.
* @param[in] ucTCPFlags The flags to determine what kind of packet this is.
*
* @return pdFAIL always indicating that the packet was not consumed.
*/
BaseType_t prvTCPSendSpecialPktHelper_IPV6( NetworkBufferDescriptor_t * pxNetworkBuffer,
uint8_t ucTCPFlags )
{
#if ( ipconfigIGNORE_UNKNOWN_PACKETS == 1 )
/* Configured to ignore unknown packets just suppress a compiler warning. */
( void ) pxNetworkBuffer;
( void ) ucTCPFlags;
#else
{
/* Map the ethernet buffer onto the TCPPacket_t struct for easy access to the fields. */
/* MISRA Ref 11.3.1 [Misaligned access] */
/* More details at: https://github.com/FreeRTOS/FreeRTOS-Plus-TCP/blob/main/MISRA.md#rule-113 */
/* coverity[misra_c_2012_rule_11_3_violation] */
TCPPacket_IPv6_t * pxTCPPacket = ( ( TCPPacket_IPv6_t * ) pxNetworkBuffer->pucEthernetBuffer );
const uint32_t ulSendLength =
ipSIZE_OF_IPv6_HEADER + ipSIZE_OF_TCP_HEADER; /* Plus 0 options. */
uint8_t ucFlagsReceived = pxTCPPacket->xTCPHeader.ucTCPFlags;
pxTCPPacket->xTCPHeader.ucTCPFlags = ucTCPFlags;
pxTCPPacket->xTCPHeader.ucTCPOffset = ( ipSIZE_OF_TCP_HEADER ) << 2;
if( ( ucFlagsReceived & tcpTCP_FLAG_SYN ) != 0U )
{
/* A synchronize packet is received. It counts as 1 pseudo byte of data,
* so increase the variable with 1. Before sending a reply, the values of
* 'ulSequenceNumber' and 'ulAckNr' will be swapped. */
uint32_t ulSequenceNumber = FreeRTOS_ntohl( pxTCPPacket->xTCPHeader.ulSequenceNumber );
ulSequenceNumber++;
pxTCPPacket->xTCPHeader.ulSequenceNumber = FreeRTOS_htonl( ulSequenceNumber );
}
prvTCPReturnPacket( NULL, pxNetworkBuffer, ulSendLength, pdFALSE );
}
#endif /* !ipconfigIGNORE_UNKNOWN_PACKETS */
/* The packet was not consumed. */
return pdFAIL;
}
/*-----------------------------------------------------------*/
/* *INDENT-OFF* */
#endif /* ( ipconfigUSE_IPv6 != 0 ) && ( ipconfigUSE_TCP == 1 ) */
/* *INDENT-ON* */