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FreeRTOS-Plus-TCP/source/FreeRTOS_TCP_Transmission.c
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/*
* FreeRTOS+TCP V4.3.0
* 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.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 "FreeRTOSIPConfigDefaults.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. */
#if ipconfigUSE_TCP == 1
static BaseType_t prvTCPMakeSurePrepared( FreeRTOS_Socket_t * pxSocket );
/* Resolve the MAC-address of the peer and initialise the first SYN packet. */
static BaseType_t prvTCPPrepareConnect( FreeRTOS_Socket_t * pxSocket );
#if ipconfigIS_ENABLED( ipconfigUSE_TCP_WIN )
static uint8_t prvWinScaleFactor( const FreeRTOS_Socket_t * pxSocket );
#endif
/*------------------------------------------------------------------------*/
/**
* @brief Check if the outgoing connection is already prepared, if not
* call prvTCPPrepareConnect() to continue the preparation.
* @param[in] pxSocket The socket that wants to connect.
* @return Returns pdTRUE if the connection is prepared, i.e. the MAC-
* address of the peer is already known. */
static BaseType_t prvTCPMakeSurePrepared( FreeRTOS_Socket_t * pxSocket )
{
BaseType_t xReturn = pdTRUE;
if( pxSocket->u.xTCP.bits.bConnPrepared == pdFALSE_UNSIGNED )
{
if( prvTCPPrepareConnect( pxSocket ) != pdTRUE )
{
/* The preparation of a connection ( resolution ) is not yet ready. */
xReturn = pdFALSE;
}
}
return xReturn;
}
/*-----------------------------------------------------------*/
/**
* @brief prvTCPSendPacket() will be called when the socket time-out has been reached.
*
* @param[in] pxSocket The socket owning the connection.
*
* @return Number of bytes to be sent.
*
* @note It is only called by xTCPSocketCheck().
*/
int32_t prvTCPSendPacket( FreeRTOS_Socket_t * pxSocket )
{
int32_t lResult = 0;
UBaseType_t uxOptionsLength, uxIntermediateResult = 0;
NetworkBufferDescriptor_t * pxNetworkBuffer;
if( pxSocket->u.xTCP.eTCPState != eCONNECT_SYN )
{
/* The connection is in a state other than SYN. */
pxNetworkBuffer = NULL;
/* prvTCPSendRepeated() will only create a network buffer if necessary,
* i.e. when data must be sent to the peer. */
lResult = prvTCPSendRepeated( pxSocket, &pxNetworkBuffer );
if( pxNetworkBuffer != NULL )
{
vReleaseNetworkBufferAndDescriptor( pxNetworkBuffer );
}
}
else
{
if( pxSocket->u.xTCP.ucRepCount >= 3U )
{
/* The connection is in the SYN status. The packet will be repeated
* to most 3 times. When there is no response, the socket get the
* status 'eCLOSE_WAIT'. */
FreeRTOS_debug_printf( ( "Connect: giving up %xip:%u\n",
( unsigned ) pxSocket->u.xTCP.xRemoteIP.ulIP_IPv4, /* IP address of remote machine. */
pxSocket->u.xTCP.usRemotePort ) ); /* Port on remote machine. */
vTCPStateChange( pxSocket, eCLOSE_WAIT );
}
else if( prvTCPMakeSurePrepared( pxSocket ) == pdTRUE )
{
ProtocolHeaders_t * pxProtocolHeaders;
/* Or else, if the connection has been prepared, or can be prepared
* now, proceed to send the packet with the SYN flag.
* prvTCPPrepareConnect() prepares 'xPacket' and returns pdTRUE if
* the Ethernet address of the peer or the gateway is found. */
/* 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 ) ] ) );
/* About to send a SYN packet. Call prvSetSynAckOptions() to set
* the proper options: The size of MSS and whether SACK's are
* allowed. */
uxOptionsLength = prvSetSynAckOptions( pxSocket, &( pxProtocolHeaders->xTCPHeader ) );
/* Return the number of bytes to be sent. */
uxIntermediateResult = uxIPHeaderSizeSocket( pxSocket ) + ipSIZE_OF_TCP_HEADER + uxOptionsLength;
lResult = ( int32_t ) uxIntermediateResult;
/* Set the TCP offset field: ipSIZE_OF_TCP_HEADER equals 20 and
* uxOptionsLength is always a multiple of 4. The complete expression
* would be:
* ucTCPOffset = ( ( ipSIZE_OF_TCP_HEADER + uxOptionsLength ) / 4 ) << 4 */
pxProtocolHeaders->xTCPHeader.ucTCPOffset = ( uint8_t ) ( ( ipSIZE_OF_TCP_HEADER + uxOptionsLength ) << 2 );
/* Repeat Count is used for a connecting socket, to limit the number
* of tries. */
pxSocket->u.xTCP.ucRepCount++;
/* Send the SYN message to make a connection. The messages is
* stored in the socket field 'xPacket'. It will be wrapped in a
* pseudo network buffer descriptor before it will be sent. */
prvTCPReturnPacket( pxSocket, NULL, ( uint32_t ) lResult, pdFALSE );
}
else
{
/* Nothing to do. */
}
}
/* Return the total number of bytes sent. */
return lResult;
}
/*-----------------------------------------------------------*/
/**
* @brief prvTCPSendRepeated will try to send a series of messages, as
* long as there is data to be sent and as long as the transmit
* window isn't full.
*
* @param[in] pxSocket The socket owning the connection.
* @param[in,out] ppxNetworkBuffer Pointer to pointer to the network buffer.
*
* @return Total number of bytes sent.
*/
int32_t prvTCPSendRepeated( FreeRTOS_Socket_t * pxSocket,
NetworkBufferDescriptor_t ** ppxNetworkBuffer )
{
UBaseType_t uxIndex;
int32_t lResult = 0;
UBaseType_t uxOptionsLength = 0U;
int32_t xSendLength;
for( uxIndex = 0U; uxIndex < ( UBaseType_t ) SEND_REPEATED_COUNT; uxIndex++ )
{
/* prvTCPPrepareSend() might allocate a network buffer if there is data
* to be sent. */
xSendLength = prvTCPPrepareSend( pxSocket, ppxNetworkBuffer, uxOptionsLength );
if( xSendLength <= 0 )
{
break;
}
/* And return the packet to the peer. */
prvTCPReturnPacket( pxSocket, *ppxNetworkBuffer, ( uint32_t ) xSendLength, ipconfigZERO_COPY_TX_DRIVER );
#if ( ipconfigZERO_COPY_TX_DRIVER != 0 )
{
*ppxNetworkBuffer = NULL;
}
#endif /* ipconfigZERO_COPY_TX_DRIVER */
lResult += xSendLength;
}
/* Return the total number of bytes sent. */
return lResult;
}
/*-----------------------------------------------------------*/
/**
* @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( FreeRTOS_Socket_t * pxSocket,
NetworkBufferDescriptor_t * pxDescriptor,
uint32_t ulLen,
BaseType_t xReleaseAfterSend )
{
const NetworkBufferDescriptor_t * pxNetworkBuffer = pxDescriptor;
BaseType_t xIsIPv6 = pdFALSE;
if( pxNetworkBuffer != NULL )
{
#if ( ipconfigUSE_IPv6 != 0 )
if( uxIPHeaderSizePacket( pxNetworkBuffer ) == ipSIZE_OF_IPv6_HEADER )
{
xIsIPv6 = pdTRUE;
}
#endif /* ( ipconfigUSE_IPv6 != 0 ) */
}
else if( pxSocket != NULL )
{
#if ( ipconfigUSE_IPv6 != 0 )
if( uxIPHeaderSizeSocket( pxSocket ) == ipSIZE_OF_IPv6_HEADER )
{
xIsIPv6 = pdTRUE;
}
#endif /* ( ipconfigUSE_IPv6 != 0 ) */
}
else
{
/* prvTCPReturnPacket_IPVx() needs either a network buffer, or a socket. */
configASSERT( pdFALSE );
}
#if ( ipconfigUSE_IPv6 != 0 )
if( xIsIPv6 == pdTRUE )
{
prvTCPReturnPacket_IPV6( pxSocket, pxDescriptor, ulLen, xReleaseAfterSend );
}
#endif /* ( ipconfigUSE_IPv6 != 0 ) */
#if ( ipconfigUSE_IPv4 != 0 )
if( xIsIPv6 == pdFALSE )
{
prvTCPReturnPacket_IPV4( pxSocket, pxDescriptor, ulLen, xReleaseAfterSend );
}
#endif /* ( ipconfigUSE_IPv4 != 0 ) */
}
/*-----------------------------------------------------------*/
/**
* @brief Called by prvTCPReturnPacket(), this function will set the the window
* size on this side: 'xTCPHeader.usWindow'.
* @param[in] pxSocket The socket on which the packet is being sent.
* @param[in] pxNetworkBuffer The network buffer carrying the outgoing message.
* @param[in] uxIPHeaderSize The size of the IP-header, which depends on the IP-type.
*/
void prvTCPReturn_CheckTCPWindow( FreeRTOS_Socket_t * pxSocket,
const NetworkBufferDescriptor_t * pxNetworkBuffer,
size_t uxIPHeaderSize )
{
/* Calculate the space in the RX buffer in order to advertise the
* size of this socket's reception window. */
const TCPWindow_t * pxTCPWindow = &( pxSocket->u.xTCP.xTCPWindow );
uint32_t ulFrontSpace, ulSpace, ulWinSize;
ProtocolHeaders_t * pxProtocolHeaders;
/* 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( pxSocket->u.xTCP.rxStream != NULL )
{
/* An RX stream was created already, see how much space is
* available. */
ulFrontSpace = ( uint32_t ) uxStreamBufferFrontSpace( pxSocket->u.xTCP.rxStream );
}
else
{
/* No RX stream has been created, the full stream size is
* available. */
ulFrontSpace = ( uint32_t ) pxSocket->u.xTCP.uxRxStreamSize;
}
/* Take the minimum of the RX buffer space and the RX window size. */
ulSpace = FreeRTOS_min_uint32( pxTCPWindow->xSize.ulRxWindowLength, ulFrontSpace );
if( ( pxSocket->u.xTCP.bits.bLowWater != pdFALSE_UNSIGNED ) || ( pxSocket->u.xTCP.bits.bRxStopped != pdFALSE_UNSIGNED ) )
{
/* The low-water mark was reached, meaning there was little
* space left. The socket will wait until the application has read
* or flushed the incoming data, and 'zero-window' will be
* advertised. */
ulSpace = 0U;
}
/* If possible, advertise an RX window size of at least 1 MSS, otherwise
* the peer might start 'zero window probing', i.e. sending small packets
* (1, 2, 4, 8... bytes). */
if( ( ulSpace < pxSocket->u.xTCP.usMSS ) && ( ulFrontSpace >= pxSocket->u.xTCP.usMSS ) )
{
ulSpace = pxSocket->u.xTCP.usMSS;
}
/* Avoid overflow of the 16-bit win field. */
#if ( ipconfigUSE_TCP_WIN != 0 )
{
ulWinSize = ( ulSpace >> pxSocket->u.xTCP.ucMyWinScaleFactor );
}
#else
{
ulWinSize = ulSpace;
}
#endif
if( ulWinSize > 0xfffcU )
{
ulWinSize = 0xfffcU;
}
pxProtocolHeaders->xTCPHeader.usWindow = FreeRTOS_htons( ( uint16_t ) ulWinSize );
/* The new window size has been advertised, switch off the flag. */
pxSocket->u.xTCP.bits.bWinChange = pdFALSE_UNSIGNED;
/* Later on, when deciding to delay an ACK, a precise estimate is needed
* of the free RX space. At this moment, 'ulHighestRxAllowed' would be the
* highest sequence number minus 1 that the socket will accept. */
pxSocket->u.xTCP.ulHighestRxAllowed = pxTCPWindow->rx.ulCurrentSequenceNumber + ulSpace;
}
/*-----------------------------------------------------------*/
/**
* @brief Called by prvTCPReturnPacket(), this function sets the sequence and ack numbers
* in the TCP-header.
* @param[in] pxSocket The socket on which the packet is being sent.
* @param[in] pxNetworkBuffer The network buffer carrying the outgoing message.
* @param[in] uxIPHeaderSize The size of the IP-header, which depends on the IP-type.
* @param[in] ulLen The size of the packet minus the size of the Ethernet header.
*
*/
void prvTCPReturn_SetSequenceNumber( FreeRTOS_Socket_t * pxSocket,
const NetworkBufferDescriptor_t * pxNetworkBuffer,
size_t uxIPHeaderSize,
uint32_t ulLen )
{
ProtocolHeaders_t * pxProtocolHeaders;
const TCPWindow_t * pxTCPWindow = &( pxSocket->u.xTCP.xTCPWindow );
/* 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 ( ipconfigTCP_KEEP_ALIVE == 1 )
if( pxSocket->u.xTCP.bits.bSendKeepAlive != pdFALSE_UNSIGNED )
{
/* Sending a keep-alive packet, send the current sequence number
* minus 1, which will be recognised as a keep-alive packet and
* responded to by acknowledging the last byte. */
pxSocket->u.xTCP.bits.bSendKeepAlive = pdFALSE_UNSIGNED;
pxSocket->u.xTCP.bits.bWaitKeepAlive = pdTRUE_UNSIGNED;
pxProtocolHeaders->xTCPHeader.ulSequenceNumber = pxSocket->u.xTCP.xTCPWindow.ulOurSequenceNumber - 1U;
pxProtocolHeaders->xTCPHeader.ulSequenceNumber = FreeRTOS_htonl( pxProtocolHeaders->xTCPHeader.ulSequenceNumber );
}
else
#endif /* if ( ipconfigTCP_KEEP_ALIVE == 1 ) */
{
pxProtocolHeaders->xTCPHeader.ulSequenceNumber = FreeRTOS_htonl( pxSocket->u.xTCP.xTCPWindow.ulOurSequenceNumber );
if( ( pxProtocolHeaders->xTCPHeader.ucTCPFlags & ( uint8_t ) tcpTCP_FLAG_FIN ) != 0U )
{
/* Suppress FIN in case this packet carries earlier data to be
* retransmitted. */
uint32_t ulDataLen = ( uint32_t ) ( ulLen - ( ipSIZE_OF_TCP_HEADER + uxIPHeaderSizeSocket( pxSocket ) ) );
if( ( pxTCPWindow->ulOurSequenceNumber + ulDataLen ) != pxTCPWindow->tx.ulFINSequenceNumber )
{
pxProtocolHeaders->xTCPHeader.ucTCPFlags &= ( ( uint8_t ) ~tcpTCP_FLAG_FIN );
FreeRTOS_debug_printf( ( "Suppress FIN for %u + %u < %u\n",
( unsigned int ) ( pxTCPWindow->ulOurSequenceNumber - pxTCPWindow->tx.ulFirstSequenceNumber ),
( unsigned int ) ulDataLen,
( unsigned int ) ( pxTCPWindow->tx.ulFINSequenceNumber - pxTCPWindow->tx.ulFirstSequenceNumber ) ) );
}
}
}
/* Tell which sequence number is expected next time */
pxProtocolHeaders->xTCPHeader.ulAckNr = FreeRTOS_htonl( pxTCPWindow->rx.ulCurrentSequenceNumber );
}
/*-----------------------------------------------------------*/
/**
* @brief Create the TCP window for the given socket.
*
* @param[in] pxSocket The socket for which the window is being created.
*
* @note The SYN event is very important: the sequence numbers, which have a kind of
* random starting value, are being synchronized. The sliding window manager
* (in FreeRTOS_TCP_WIN.c) needs to know them, along with the Maximum Segment
* Size (MSS).
*/
BaseType_t prvTCPCreateWindow( FreeRTOS_Socket_t * pxSocket )
{
BaseType_t xReturn;
uint32_t ulRxWindowSize = ( uint32_t ) pxSocket->u.xTCP.uxRxWinSize;
uint32_t ulTxWindowSize = ( uint32_t ) pxSocket->u.xTCP.uxTxWinSize;
if( xTCPWindowLoggingLevel != 0 )
{
FreeRTOS_debug_printf( ( "Limits (using): TCP Win size %u Water %u <= %u <= %u\n",
( unsigned ) ( pxSocket->u.xTCP.uxRxWinSize * ipconfigTCP_MSS ),
( unsigned ) pxSocket->u.xTCP.uxLittleSpace,
( unsigned ) pxSocket->u.xTCP.uxEnoughSpace,
( unsigned ) pxSocket->u.xTCP.uxRxStreamSize ) );
}
xReturn = xTCPWindowCreate(
&pxSocket->u.xTCP.xTCPWindow,
ulRxWindowSize * ipconfigTCP_MSS,
ulTxWindowSize * ipconfigTCP_MSS,
pxSocket->u.xTCP.xTCPWindow.rx.ulCurrentSequenceNumber,
pxSocket->u.xTCP.xTCPWindow.ulOurSequenceNumber,
( uint32_t ) pxSocket->u.xTCP.usMSS );
return xReturn;
}
/*-----------------------------------------------------------*/
/**
* @brief Resolve 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 through address resolution.
* In case the target IP address is not within the netmask, the hardware address
* of the gateway will be used.
*/
static BaseType_t prvTCPPrepareConnect( FreeRTOS_Socket_t * pxSocket )
{
BaseType_t xReturn = pdTRUE;
switch( pxSocket->bits.bIsIPv6 ) /* LCOV_EXCL_BR_LINE */
{
#if ( ipconfigUSE_IPv4 != 0 )
case pdFALSE_UNSIGNED:
xReturn = prvTCPPrepareConnect_IPV4( pxSocket );
break;
#endif /* ( ipconfigUSE_IPv4 != 0 ) */
#if ( ipconfigUSE_IPv6 != 0 )
case pdTRUE_UNSIGNED:
xReturn = prvTCPPrepareConnect_IPV6( pxSocket );
break;
#endif /* ( ipconfigUSE_IPv6 != 0 ) */
default: /* LCOV_EXCL_LINE */
/* MISRA 16.4 Compliance */
break; /* LCOV_EXCL_LINE */
}
return xReturn;
}
/*-----------------------------------------------------------*/
#if ( ipconfigUSE_TCP_WIN != 0 )
/**
* @brief Get the window scaling factor for the TCP connection.
*
* @param[in] pxSocket The socket owning the TCP connection.
*
* @return The scaling factor.
*/
static uint8_t prvWinScaleFactor( const FreeRTOS_Socket_t * pxSocket )
{
size_t uxWinSize;
uint8_t ucFactor;
/* 'xTCP.uxRxWinSize' is the size of the reception window in units of MSS. */
uxWinSize = pxSocket->u.xTCP.uxRxWinSize * ( size_t ) pxSocket->u.xTCP.usMSS;
ucFactor = 0U;
while( uxWinSize > 0xffffU )
{
/* Divide by two and increase the binary factor by 1. */
uxWinSize >>= 1;
ucFactor++;
}
FreeRTOS_debug_printf( ( "prvWinScaleFactor: uxRxWinSize %u MSS %u Factor %u\n",
( unsigned ) pxSocket->u.xTCP.uxRxWinSize,
pxSocket->u.xTCP.usMSS,
ucFactor ) );
return ucFactor;
}
#endif /* if ( ipconfigUSE_TCP_WIN != 0 ) */
/*-----------------------------------------------------------*/
/**
* @brief When opening a TCP connection, while SYN's are being sent, the parties may
* communicate what MSS (Maximum Segment Size) they intend to use, whether Selective
* ACK's ( SACK ) are supported, and the size of the reception window ( WSOPT ).
*
* @param[in] pxSocket The socket being used for communication. It is used to set
* the MSS.
* @param[in,out] pxTCPHeader The TCP packet header being used in the SYN transmission.
* The MSS and corresponding options shall be set in this
* header itself.
*
* @return The option length after the TCP header was updated.
*
* @note MSS is the net size of the payload, an is always smaller than MTU.
*/
UBaseType_t prvSetSynAckOptions( FreeRTOS_Socket_t * pxSocket,
TCPHeader_t * pxTCPHeader )
{
uint16_t usMSS = pxSocket->u.xTCP.usMSS;
UBaseType_t uxOptionsLength;
/* We send out the TCP Maximum Segment Size option with our SYN[+ACK]. */
pxTCPHeader->ucOptdata[ 0 ] = ( uint8_t ) tcpTCP_OPT_MSS;
pxTCPHeader->ucOptdata[ 1 ] = ( uint8_t ) tcpTCP_OPT_MSS_LEN;
pxTCPHeader->ucOptdata[ 2 ] = ( uint8_t ) ( usMSS >> 8 );
pxTCPHeader->ucOptdata[ 3 ] = ( uint8_t ) ( usMSS & 0xffU );
#if ( ipconfigUSE_TCP_WIN != 0 )
{
pxSocket->u.xTCP.ucMyWinScaleFactor = prvWinScaleFactor( pxSocket );
pxTCPHeader->ucOptdata[ 4 ] = tcpTCP_OPT_NOOP;
pxTCPHeader->ucOptdata[ 5 ] = ( uint8_t ) ( tcpTCP_OPT_WSOPT );
pxTCPHeader->ucOptdata[ 6 ] = ( uint8_t ) ( tcpTCP_OPT_WSOPT_LEN );
pxTCPHeader->ucOptdata[ 7 ] = ( uint8_t ) pxSocket->u.xTCP.ucMyWinScaleFactor;
uxOptionsLength = 8U;
}
#else
{
uxOptionsLength = 4U;
}
#endif /* if ( ipconfigUSE_TCP_WIN != 0 ) */
#if ( ipconfigUSE_TCP_WIN != 0 )
{
pxTCPHeader->ucOptdata[ uxOptionsLength ] = tcpTCP_OPT_NOOP;
pxTCPHeader->ucOptdata[ uxOptionsLength + 1U ] = tcpTCP_OPT_NOOP;
pxTCPHeader->ucOptdata[ uxOptionsLength + 2U ] = tcpTCP_OPT_SACK_P; /* 4: Sack-Permitted Option. */
pxTCPHeader->ucOptdata[ uxOptionsLength + 3U ] = 2U; /* 2: length of this option. */
uxOptionsLength += 4U;
}
#endif /* ipconfigUSE_TCP_WIN == 0 */
return uxOptionsLength; /* bytes, not words. */
}
/**
* @brief Check if the size of a network buffer is big enough to hold the outgoing message.
* Allocate a new bigger network buffer when necessary.
*
* @param[in] pxSocket Socket whose buffer is being resized.
* @param[in] pxNetworkBuffer The network buffer whose size is being increased.
* @param[in] lDataLen Length of the data to be put in the buffer.
* @param[in] uxOptionsLength Length of options.
*
* @return If the resizing is successful: The new buffer with the size being asked for
* with old data copied in it.
* Else, NULL.
*
* @note The old network buffer will be released if the resizing is successful and
* cannot be used any longer.
*/
NetworkBufferDescriptor_t * prvTCPBufferResize( const FreeRTOS_Socket_t * pxSocket,
NetworkBufferDescriptor_t * pxNetworkBuffer,
int32_t lDataLen,
UBaseType_t uxOptionsLength )
{
NetworkBufferDescriptor_t * pxReturn;
size_t uxNeeded;
BaseType_t xResize;
if( xBufferAllocFixedSize != pdFALSE )
{
/* Network buffers are created with a fixed size and can hold the largest
* MTU. */
uxNeeded = ( size_t ) ipTOTAL_ETHERNET_FRAME_SIZE;
/* and therefore, the buffer won't be too small.
* Only ask for a new network buffer in case none was supplied. */
if( pxNetworkBuffer == NULL )
{
xResize = pdTRUE;
}
else
{
xResize = pdFALSE;
}
}
else
{
/* Network buffers are created with a variable size. See if it must
* grow. */
uxNeeded = ipSIZE_OF_ETH_HEADER + uxIPHeaderSizeSocket( pxSocket ) + ipSIZE_OF_TCP_HEADER + uxOptionsLength;
uxNeeded += ( size_t ) lDataLen;
if( uxNeeded < sizeof( pxSocket->u.xTCP.xPacket.u.ucLastPacket ) )
{
uxNeeded = sizeof( pxSocket->u.xTCP.xPacket.u.ucLastPacket );
}
/* In case we were called from a TCP timer event, a buffer must be
* created. Otherwise, test 'xDataLength' of the provided buffer. */
if( ( pxNetworkBuffer == NULL ) || ( pxNetworkBuffer->xDataLength < uxNeeded ) )
{
xResize = pdTRUE;
}
else
{
xResize = pdFALSE;
}
}
if( xResize != pdFALSE )
{
/* The caller didn't provide a network buffer or the provided buffer is
* too small. As we must send-out a data packet, a buffer will be created
* here. */
pxReturn = pxGetNetworkBufferWithDescriptor( uxNeeded, 0U );
if( pxReturn != NULL )
{
/* Set the actual packet size, in case the returned buffer is larger. */
pxReturn->xDataLength = uxNeeded;
/* Copy the existing data to the new created buffer. */
if( pxNetworkBuffer != NULL )
{
/* Either from the previous buffer... */
( void ) memcpy( pxReturn->pucEthernetBuffer, pxNetworkBuffer->pucEthernetBuffer, pxNetworkBuffer->xDataLength );
/* ...and release it. */
vReleaseNetworkBufferAndDescriptor( pxNetworkBuffer );
}
else
{
/* Or from the socket field 'xTCP.xPacket'. */
( void ) memcpy( pxReturn->pucEthernetBuffer, pxSocket->u.xTCP.xPacket.u.ucLastPacket, sizeof( pxSocket->u.xTCP.xPacket.u.ucLastPacket ) );
}
}
}
else
{
/* xResize is false, the network buffer provided was big enough. */
configASSERT( pxNetworkBuffer != NULL ); /* LCOV_EXCL_BR_LINE this branch will not be covered, since it would never be NULL. to tell lint: when xResize is false, pxNetworkBuffer is not NULL. */
pxReturn = pxNetworkBuffer;
pxNetworkBuffer->xDataLength = ( size_t ) ( ipSIZE_OF_ETH_HEADER + uxIPHeaderSizeSocket( pxSocket ) + ipSIZE_OF_TCP_HEADER + uxOptionsLength ) + ( size_t ) lDataLen;
}
return pxReturn;
}
/*-----------------------------------------------------------*/
/**
* @brief Called by prvTCPReturnPacket(), this function makes sure that the network buffer
* has 'pxEndPoint' set properly.
* @param[in] pxSocket The socket on which the packet is being sent.
* @param[in] pxNetworkBuffer The network buffer carrying the outgoing message.
* @param[in] uxIPHeaderSize The size of the IP-header, which depends on the IP-type.
*/
void prvTCPReturn_SetEndPoint( const FreeRTOS_Socket_t * pxSocket,
NetworkBufferDescriptor_t * pxNetworkBuffer,
size_t uxIPHeaderSize )
{
#if ( ipconfigUSE_IPv4 != 0 )
const IPHeader_t * pxIPHeader = NULL;
#endif
#if ( ipconfigUSE_IPv6 != 0 )
const IPHeader_IPv6_t * pxIPHeader_IPv6 = NULL;
#endif
if( ( pxSocket != NULL ) && ( pxSocket->pxEndPoint != NULL ) )
{
pxNetworkBuffer->pxEndPoint = pxSocket->pxEndPoint;
}
else
{
FreeRTOS_printf( ( "prvTCPReturnPacket: No pxEndPoint yet?\n" ) );
switch( uxIPHeaderSize )
{
#if ( ipconfigUSE_IPv4 != 0 )
case ipSIZE_OF_IPv4_HEADER:
/*_RB_ Was FreeRTOS_FindEndPointOnIP_IPv4() but changed to FreeRTOS_FindEndPointOnNetMask()
* as it is using the destination address. I'm confused here as sometimes the addresses are swapped. */
/* 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_t * ) &( pxNetworkBuffer->pucEthernetBuffer[ ipSIZE_OF_ETH_HEADER ] ) );
pxNetworkBuffer->pxEndPoint = FreeRTOS_FindEndPointOnNetMask( pxIPHeader->ulDestinationIPAddress );
if( pxNetworkBuffer->pxEndPoint == NULL )
{
FreeRTOS_printf( ( "prvTCPReturnPacket: no such end-point %xip => %xip\n",
( unsigned int ) FreeRTOS_ntohl( pxIPHeader->ulSourceIPAddress ),
( unsigned int ) FreeRTOS_ntohl( pxIPHeader->ulDestinationIPAddress ) ) );
}
break;
#endif /* ( ipconfigUSE_IPv4 != 0 ) */
#if ( ipconfigUSE_IPv6 != 0 )
case ipSIZE_OF_IPv6_HEADER:
/* 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_IPv6 = ( ( IPHeader_IPv6_t * ) &( pxNetworkBuffer->pucEthernetBuffer[ ipSIZE_OF_ETH_HEADER ] ) );
pxNetworkBuffer->pxEndPoint = FreeRTOS_FindEndPointOnIP_IPv6( &( pxIPHeader_IPv6->xDestinationAddress ) );
if( pxNetworkBuffer->pxEndPoint == NULL )
{
FreeRTOS_printf( ( "prvTCPReturnPacket: no such end-point %pip => %pip\n",
( void * ) pxIPHeader_IPv6->xSourceAddress.ucBytes,
( void * ) pxIPHeader_IPv6->xDestinationAddress.ucBytes ) );
}
break;
#endif /* ( ipconfigUSE_IPv6 != 0 ) */
default:
/* Shouldn't reach here */
pxNetworkBuffer->pxEndPoint = NULL;
break;
}
if( pxNetworkBuffer->pxEndPoint != NULL )
{
FreeRTOS_printf( ( "prvTCPReturnPacket: packet's end-point %02x-%02x\n",
pxNetworkBuffer->pxEndPoint->xMACAddress.ucBytes[ 4 ],
pxNetworkBuffer->pxEndPoint->xMACAddress.ucBytes[ 5 ] ) );
}
}
}
/*-----------------------------------------------------------*/
/**
* @brief Prepare an outgoing message, in case anything has to be sent.
*
* @param[in] pxSocket The socket owning the connection.
* @param[in,out] ppxNetworkBuffer Pointer to the pointer to the network buffer.
* @param[in] uxOptionsLength The length of the TCP options.
*
* @return Length of the data to be sent if everything is correct. Else, -1
* is returned in case of any error.
*/
int32_t prvTCPPrepareSend( FreeRTOS_Socket_t * pxSocket,
NetworkBufferDescriptor_t ** ppxNetworkBuffer,
UBaseType_t uxOptionsLength )
{
int32_t lDataLen;
uint8_t * pucEthernetBuffer, * pucSendData;
ProtocolHeaders_t * pxProtocolHeaders;
size_t uxOffset;
uint32_t ulDataGot, ulDistance;
TCPWindow_t * pxTCPWindow;
NetworkBufferDescriptor_t * pxNewBuffer;
int32_t lStreamPos;
UBaseType_t uxIntermediateResult = 0;
if( ( *ppxNetworkBuffer ) != NULL )
{
/* A network buffer descriptor was already supplied */
pucEthernetBuffer = ( *ppxNetworkBuffer )->pucEthernetBuffer;
}
else
{
/* For now let it point to the last packet header */
pucEthernetBuffer = pxSocket->u.xTCP.xPacket.u.ucLastPacket;
}
/* Map the ethernet buffer onto the ProtocolHeader_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] */
pxProtocolHeaders = ( ( ProtocolHeaders_t * ) &( pucEthernetBuffer[ ipSIZE_OF_ETH_HEADER + uxIPHeaderSizeSocket( pxSocket ) ] ) );
pxTCPWindow = &( pxSocket->u.xTCP.xTCPWindow );
lDataLen = 0;
lStreamPos = 0;
pxProtocolHeaders->xTCPHeader.ucTCPFlags |= tcpTCP_FLAG_ACK;
if( pxSocket->u.xTCP.txStream != NULL )
{
/* ulTCPWindowTxGet will return the amount of data which may be sent
* along with the position in the txStream.
* Why check for MSS > 1 ?
* Because some TCP-stacks (like uIP) use it for flow-control. */
if( pxSocket->u.xTCP.usMSS > 1U )
{
lDataLen = ( int32_t ) ulTCPWindowTxGet( pxTCPWindow, pxSocket->u.xTCP.ulWindowSize, &lStreamPos );
}
if( lDataLen > 0 )
{
/* Check if the current network buffer is big enough, if not,
* resize it. */
pxNewBuffer = prvTCPBufferResize( pxSocket, *ppxNetworkBuffer, lDataLen, uxOptionsLength );
if( pxNewBuffer != NULL )
{
*ppxNetworkBuffer = pxNewBuffer;
pucEthernetBuffer = pxNewBuffer->pucEthernetBuffer;
/* Map the byte stream onto ProtocolHeaders_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] */
pxProtocolHeaders = ( ( ProtocolHeaders_t * ) &( pucEthernetBuffer[ ipSIZE_OF_ETH_HEADER + uxIPHeaderSizeSocket( pxSocket ) ] ) );
pucSendData = &( pucEthernetBuffer[ ipSIZE_OF_ETH_HEADER + uxIPHeaderSizeSocket( pxSocket ) + ipSIZE_OF_TCP_HEADER + uxOptionsLength ] );
/* Translate the position in txStream to an offset from the tail
* marker. */
uxOffset = uxStreamBufferDistance( pxSocket->u.xTCP.txStream, pxSocket->u.xTCP.txStream->uxTail, ( size_t ) lStreamPos );
/* Here data is copied from the txStream in 'peek' mode. Only
* when the packets are acked, the tail marker will be updated. */
ulDataGot = ( uint32_t ) uxStreamBufferGet( pxSocket->u.xTCP.txStream, uxOffset, pucSendData, ( size_t ) lDataLen, pdTRUE );
#if ( ipconfigHAS_DEBUG_PRINTF != 0 )
{
if( ulDataGot != ( uint32_t ) lDataLen )
{
FreeRTOS_debug_printf( ( "uxStreamBufferGet: pos %d offs %u only %u != %d\n",
( int ) lStreamPos, ( unsigned ) uxOffset, ( unsigned ) ulDataGot, ( int ) lDataLen ) );
}
}
#endif
/* If the owner of the socket requests a closure, add the FIN
* flag to the last packet. */
if( pxSocket->u.xTCP.bits.bCloseRequested != pdFALSE_UNSIGNED )
{
ulDistance = ( uint32_t ) uxStreamBufferDistance( pxSocket->u.xTCP.txStream, ( size_t ) lStreamPos, pxSocket->u.xTCP.txStream->uxHead );
if( ulDistance == ulDataGot )
{
#if ( ipconfigHAS_DEBUG_PRINTF == 1 )
{
/* the order of volatile accesses is undefined
* so such workaround */
size_t uxHead = pxSocket->u.xTCP.txStream->uxHead;
size_t uxMid = pxSocket->u.xTCP.txStream->uxMid;
size_t uxTail = pxSocket->u.xTCP.txStream->uxTail;
FreeRTOS_debug_printf( ( "CheckClose %u <= %u (%u <= %u <= %u)\n",
( unsigned ) ulDataGot, ( unsigned ) ulDistance,
( unsigned ) uxTail, ( unsigned ) uxMid, ( unsigned ) uxHead ) );
}
#endif /* if ( ipconfigHAS_DEBUG_PRINTF == 1 ) */
/* Although the socket sends a FIN, it will stay in
* ESTABLISHED until all current data has been received or
* delivered. */
pxProtocolHeaders->xTCPHeader.ucTCPFlags |= tcpTCP_FLAG_FIN;
pxTCPWindow->tx.ulFINSequenceNumber = pxTCPWindow->ulOurSequenceNumber + ( uint32_t ) lDataLen;
pxSocket->u.xTCP.bits.bFinSent = pdTRUE_UNSIGNED;
}
}
}
else
{
lDataLen = -1;
}
}
}
if( ( lDataLen >= 0 ) && ( pxSocket->u.xTCP.eTCPState == eESTABLISHED ) )
{
/* See if the socket owner wants to shutdown this connection. */
if( ( pxSocket->u.xTCP.bits.bUserShutdown != pdFALSE_UNSIGNED ) &&
( xTCPWindowTxDone( pxTCPWindow ) != pdFALSE ) )
{
pxSocket->u.xTCP.bits.bUserShutdown = pdFALSE_UNSIGNED;
pxProtocolHeaders->xTCPHeader.ucTCPFlags |= tcpTCP_FLAG_FIN;
pxSocket->u.xTCP.bits.bFinSent = pdTRUE_UNSIGNED;
pxSocket->u.xTCP.bits.bWinChange = pdTRUE_UNSIGNED;
pxTCPWindow->tx.ulFINSequenceNumber = pxTCPWindow->tx.ulCurrentSequenceNumber;
vTCPStateChange( pxSocket, eFIN_WAIT_1 );
}
#if ( ipconfigTCP_KEEP_ALIVE != 0 )
{
if( pxSocket->u.xTCP.ucKeepRepCount > 3U ) /*_RB_ Magic number. */
{
FreeRTOS_debug_printf( ( "keep-alive: giving up %xip:%u\n",
( unsigned ) pxSocket->u.xTCP.xRemoteIP.ulIP_IPv4, /* IP address of remote machine. */
pxSocket->u.xTCP.usRemotePort ) ); /* Port on remote machine. */
vTCPStateChange( pxSocket, eCLOSE_WAIT );
lDataLen = -1;
}
if( ( lDataLen == 0 ) && ( pxSocket->u.xTCP.bits.bWinChange == pdFALSE_UNSIGNED ) )
{
/* If there is no data to be sent, and no window-update message,
* we might want to send a keep-alive message. */
TickType_t xAge = xTaskGetTickCount() - pxSocket->u.xTCP.xLastAliveTime;
TickType_t xMax;
xMax = ( ( TickType_t ) ipconfigTCP_KEEP_ALIVE_INTERVAL * ( TickType_t ) configTICK_RATE_HZ );
if( pxSocket->u.xTCP.ucKeepRepCount != 0U )
{
xMax = 3U * configTICK_RATE_HZ;
}
if( xAge > xMax )
{
pxSocket->u.xTCP.xLastAliveTime = xTaskGetTickCount();
if( xTCPWindowLoggingLevel != 0 )
{
FreeRTOS_debug_printf( ( "keep-alive: %xip:%u count %u\n",
( unsigned ) pxSocket->u.xTCP.xRemoteIP.ulIP_IPv4,
pxSocket->u.xTCP.usRemotePort,
pxSocket->u.xTCP.ucKeepRepCount ) );
}
pxSocket->u.xTCP.bits.bSendKeepAlive = pdTRUE_UNSIGNED;
pxSocket->u.xTCP.usTimeout = ( ( uint16_t ) pdMS_TO_TICKS( 2500U ) );
pxSocket->u.xTCP.ucKeepRepCount++;
}
}
}
#endif /* ipconfigTCP_KEEP_ALIVE */
}
if( lDataLen >= 0 )
{
/* Anything to send, a change of the advertised window size, or maybe send a
* keep-alive message? */
if( ( lDataLen > 0 ) ||
( pxSocket->u.xTCP.bits.bWinChange != pdFALSE_UNSIGNED ) ||
( pxSocket->u.xTCP.bits.bSendKeepAlive != pdFALSE_UNSIGNED ) )
{
pxProtocolHeaders->xTCPHeader.ucTCPFlags &= ( ( uint8_t ) ~tcpTCP_FLAG_PSH );
pxProtocolHeaders->xTCPHeader.ucTCPOffset = ( uint8_t ) ( ( ipSIZE_OF_TCP_HEADER + uxOptionsLength ) << 2 ); /*_RB_ "2" needs comment. */
pxProtocolHeaders->xTCPHeader.ucTCPFlags |= ( uint8_t ) tcpTCP_FLAG_ACK;
if( lDataLen != 0L )
{
pxProtocolHeaders->xTCPHeader.ucTCPFlags |= ( uint8_t ) tcpTCP_FLAG_PSH;
}
uxIntermediateResult = uxIPHeaderSizeSocket( pxSocket ) + ipSIZE_OF_TCP_HEADER + uxOptionsLength;
lDataLen += ( int32_t ) uxIntermediateResult;
}
}
return lDataLen;
}
/*-----------------------------------------------------------*/
/**
* @brief The API FreeRTOS_send() adds data to the TX stream. Add
* this data to the windowing system to it can be transmitted.
*
* @param[in] pxSocket The socket owning the connection.
*/
void prvTCPAddTxData( FreeRTOS_Socket_t * pxSocket )
{
int32_t lCount, lLength;
/* A txStream has been created already, see if the socket has new data for
* the sliding window.
*
* uxStreamBufferMidSpace() returns the distance between rxHead and rxMid. It
* contains new Tx data which has not been passed to the sliding window yet.
* The oldest data not-yet-confirmed can be found at rxTail. */
lLength = ( int32_t ) uxStreamBufferMidSpace( pxSocket->u.xTCP.txStream );
if( lLength > 0 )
{
/* All data between txMid and rxHead will now be passed to the sliding
* window manager, so it can start transmitting them.
*
* Hand over the new data to the sliding window handler. It will be
* split-up in chunks of 1460 bytes each (or less, depending on
* ipconfigTCP_MSS). */
lCount = lTCPWindowTxAdd( &pxSocket->u.xTCP.xTCPWindow,
( uint32_t ) lLength,
( int32_t ) pxSocket->u.xTCP.txStream->uxMid,
( int32_t ) pxSocket->u.xTCP.txStream->LENGTH );
/* Move the rxMid pointer forward up to rxHead. */
if( lCount > 0 )
{
vStreamBufferMoveMid( pxSocket->u.xTCP.txStream, ( size_t ) lCount );
}
}
}
/*-----------------------------------------------------------*/
/**
* @brief Set the TCP options (if any) for the outgoing packet.
*
* @param[in] pxSocket The socket owning the connection.
* @param[in] pxNetworkBuffer The network buffer holding the packet.
*
* @return Length of the TCP options after they are set.
*/
UBaseType_t prvSetOptions( FreeRTOS_Socket_t * pxSocket,
const NetworkBufferDescriptor_t * pxNetworkBuffer )
{
/* Map the ethernet buffer onto the ProtocolHeader_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] */
ProtocolHeaders_t * pxProtocolHeaders = ( ( ProtocolHeaders_t * )
&( pxNetworkBuffer->pucEthernetBuffer[ ipSIZE_OF_ETH_HEADER + uxIPHeaderSizePacket( pxNetworkBuffer ) ] ) );
TCPHeader_t * pxTCPHeader = &pxProtocolHeaders->xTCPHeader;
const TCPWindow_t * pxTCPWindow = &pxSocket->u.xTCP.xTCPWindow;
UBaseType_t uxOptionsLength = pxTCPWindow->ucOptionLength;
#if ( ipconfigUSE_TCP_WIN == 1 )
/* memcpy() helper variables for MISRA Rule 21.15 compliance*/
const void * pvCopySource;
void * pvCopyDest;
if( uxOptionsLength != 0U )
{
/* TCP options must be sent because a packet which is out-of-order
* was received. */
if( xTCPWindowLoggingLevel >= 0 )
{
FreeRTOS_debug_printf( ( "SACK[%u,%u]: optlen %u sending %u - %u\n",
pxSocket->usLocalPort,
pxSocket->u.xTCP.usRemotePort,
( unsigned ) uxOptionsLength,
( unsigned ) ( FreeRTOS_ntohl( pxTCPWindow->ulOptionsData[ 1 ] ) - pxSocket->u.xTCP.xTCPWindow.rx.ulFirstSequenceNumber ),
( unsigned ) ( FreeRTOS_ntohl( pxTCPWindow->ulOptionsData[ 2 ] ) - pxSocket->u.xTCP.xTCPWindow.rx.ulFirstSequenceNumber ) ) );
}
/*
* Use helper variables for memcpy() source & dest to remain
* compliant with MISRA Rule 21.15. These should be
* optimized away.
*/
pvCopySource = pxTCPWindow->ulOptionsData;
pvCopyDest = pxTCPHeader->ucOptdata;
( void ) memcpy( pvCopyDest, pvCopySource, ( size_t ) uxOptionsLength );
/* The header length divided by 4, goes into the higher nibble,
* effectively a shift-left 2. */
pxTCPHeader->ucTCPOffset = ( uint8_t ) ( ( ipSIZE_OF_TCP_HEADER + uxOptionsLength ) << 2 );
}
else
#endif /* ipconfigUSE_TCP_WIN */
if( ( pxSocket->u.xTCP.eTCPState >= eESTABLISHED ) && ( pxSocket->u.xTCP.bits.bMssChange != pdFALSE_UNSIGNED ) )
{
/* TCP options must be sent because the MSS has changed. */
pxSocket->u.xTCP.bits.bMssChange = pdFALSE_UNSIGNED;
if( xTCPWindowLoggingLevel >= 0 )
{
FreeRTOS_debug_printf( ( "MSS: sending %u\n", pxSocket->u.xTCP.usMSS ) );
}
pxTCPHeader->ucOptdata[ 0 ] = tcpTCP_OPT_MSS;
pxTCPHeader->ucOptdata[ 1 ] = tcpTCP_OPT_MSS_LEN;
pxTCPHeader->ucOptdata[ 2 ] = ( uint8_t ) ( ( pxSocket->u.xTCP.usMSS ) >> 8 );
pxTCPHeader->ucOptdata[ 3 ] = ( uint8_t ) ( ( pxSocket->u.xTCP.usMSS ) & 0xffU );
uxOptionsLength = 4U;
pxTCPHeader->ucTCPOffset = ( uint8_t ) ( ( ipSIZE_OF_TCP_HEADER + uxOptionsLength ) << 2 );
}
else
{
/* Nothing. */
}
return uxOptionsLength;
}
/*-----------------------------------------------------------*/
/**
* @brief Called from prvTCPHandleState(). There is data to be sent. If
* ipconfigUSE_TCP_WIN is defined, and if only an ACK must be sent, it will be
* checked if it would better be postponed for efficiency.
*
* @param[in] pxSocket The socket owning the TCP connection.
* @param[in] ppxNetworkBuffer Pointer to pointer to the network buffer.
* @param[in] ulReceiveLength The length of the received buffer.
* @param[in] xByteCount Length of the data to be sent.
*
* @return The number of bytes actually sent.
*/
BaseType_t prvSendData( FreeRTOS_Socket_t * pxSocket,
NetworkBufferDescriptor_t ** ppxNetworkBuffer,
uint32_t ulReceiveLength,
BaseType_t xByteCount )
{
/* Map the buffer onto the ProtocolHeader_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] */
const ProtocolHeaders_t * pxProtocolHeaders = ( ( ProtocolHeaders_t * )
&( ( *ppxNetworkBuffer )->pucEthernetBuffer[ ipSIZE_OF_ETH_HEADER + uxIPHeaderSizePacket( *ppxNetworkBuffer ) ] ) );
const TCPHeader_t * pxTCPHeader = &pxProtocolHeaders->xTCPHeader;
const TCPWindow_t * pxTCPWindow = &pxSocket->u.xTCP.xTCPWindow;
/* Find out what window size we may advertised. */
int32_t lRxSpace;
BaseType_t xSendLength = xByteCount;
uint32_t ulRxBufferSpace;
#if ( ipconfigUSE_TCP_WIN == 1 )
/* Two steps to please MISRA. */
size_t uxSize = uxIPHeaderSizePacket( *ppxNetworkBuffer ) + ipSIZE_OF_TCP_HEADER;
BaseType_t xSizeWithoutData = ( BaseType_t ) uxSize;
int32_t lMinLength;
#endif
/* Set the time-out field, so that we'll be called by the IP-task in case no
* next message will be received. */
ulRxBufferSpace = pxSocket->u.xTCP.ulHighestRxAllowed - pxTCPWindow->rx.ulCurrentSequenceNumber;
lRxSpace = ( int32_t ) ulRxBufferSpace;
#if ipconfigUSE_TCP_WIN == 1
{
/* An ACK may be delayed if the peer has space for at least 2 x MSS. */
lMinLength = ( ( int32_t ) 2 ) * ( ( int32_t ) pxSocket->u.xTCP.usMSS );
/* In case we're receiving data continuously, we might postpone sending
* an ACK to gain performance. */
/* lint e9007 is OK because 'uxIPHeaderSizeSocket()' has no side-effects. */
if( ( ulReceiveLength > 0U ) && /* Data was sent to this socket. */
( lRxSpace >= lMinLength ) && /* There is Rx space for more data. */
( pxSocket->u.xTCP.bits.bFinSent == pdFALSE_UNSIGNED ) && /* Not in a closure phase. */
( xSendLength == xSizeWithoutData ) && /* No Tx data or options to be sent. */
( pxSocket->u.xTCP.eTCPState == eESTABLISHED ) && /* Connection established. */
( pxTCPHeader->ucTCPFlags == tcpTCP_FLAG_ACK ) ) /* There are no other flags than an ACK. */
{
uint32_t ulCurMSS = ( uint32_t ) pxSocket->u.xTCP.usMSS;
if( pxSocket->u.xTCP.pxAckMessage != *ppxNetworkBuffer )
{
/* There was still a delayed in queue, delete it. */
if( pxSocket->u.xTCP.pxAckMessage != NULL )
{
vReleaseNetworkBufferAndDescriptor( pxSocket->u.xTCP.pxAckMessage );
}
pxSocket->u.xTCP.pxAckMessage = *ppxNetworkBuffer;
}
if( ulReceiveLength < ulCurMSS ) /* Received a small message. */
{
pxSocket->u.xTCP.usTimeout = ( uint16_t ) tcpDELAYED_ACK_SHORT_DELAY_MS;
}
else
{
/* Normally a delayed ACK should wait 200 ms for a next incoming
* packet. Only wait 20 ms here to gain performance. A slow ACK
* for full-size message. */
pxSocket->u.xTCP.usTimeout = ( uint16_t ) pdMS_TO_TICKS( tcpDELAYED_ACK_LONGER_DELAY_MS );
if( pxSocket->u.xTCP.usTimeout < 1U ) /* LCOV_EXCL_BR_LINE, the second branch will never be hit */
{
pxSocket->u.xTCP.usTimeout = 1U; /* LCOV_EXCL_LINE, this line will not be reached */
}
}
if( ( xTCPWindowLoggingLevel > 1 ) && ( ipconfigTCP_MAY_LOG_PORT( pxSocket->usLocalPort ) ) )
{
FreeRTOS_debug_printf( ( "Send[%u->%u] del ACK %u SEQ %u (len %u) tmout %u d %d\n",
pxSocket->usLocalPort,
pxSocket->u.xTCP.usRemotePort,
( unsigned ) ( pxTCPWindow->rx.ulCurrentSequenceNumber - pxTCPWindow->rx.ulFirstSequenceNumber ),
( unsigned ) ( pxSocket->u.xTCP.xTCPWindow.ulOurSequenceNumber - pxTCPWindow->tx.ulFirstSequenceNumber ),
( unsigned ) xSendLength,
pxSocket->u.xTCP.usTimeout,
( int ) lRxSpace ) );
}
*ppxNetworkBuffer = NULL;
xSendLength = 0;
}
else if( pxSocket->u.xTCP.pxAckMessage != NULL )
{
/* As an ACK is not being delayed, remove any earlier delayed ACK
* message. */
if( pxSocket->u.xTCP.pxAckMessage != *ppxNetworkBuffer )
{
vReleaseNetworkBufferAndDescriptor( pxSocket->u.xTCP.pxAckMessage );
}
pxSocket->u.xTCP.pxAckMessage = NULL;
}
else
{
/* The ack will not be postponed, and there was no stored ack ( in 'pxAckMessage' ). */
}
}
#else /* if ipconfigUSE_TCP_WIN == 1 */
{
/* Remove compiler warnings. */
( void ) ulReceiveLength;
( void ) pxTCPHeader;
( void ) lRxSpace;
}
#endif /* ipconfigUSE_TCP_WIN */
if( xSendLength != 0 )
{
if( ( xTCPWindowLoggingLevel > 1 ) && ( ipconfigTCP_MAY_LOG_PORT( pxSocket->usLocalPort ) ) )
{
FreeRTOS_debug_printf( ( "Send[%u->%u] imm ACK %u SEQ %u (len %u)\n",
pxSocket->usLocalPort,
pxSocket->u.xTCP.usRemotePort,
( unsigned ) ( pxTCPWindow->rx.ulCurrentSequenceNumber - pxTCPWindow->rx.ulFirstSequenceNumber ),
( unsigned ) ( pxTCPWindow->ulOurSequenceNumber - pxTCPWindow->tx.ulFirstSequenceNumber ),
( unsigned ) xSendLength ) );
}
/* Set the parameter 'xReleaseAfterSend' to the value of
* ipconfigZERO_COPY_TX_DRIVER. */
prvTCPReturnPacket( pxSocket, *ppxNetworkBuffer, ( uint32_t ) xSendLength, ipconfigZERO_COPY_TX_DRIVER );
#if ( ipconfigZERO_COPY_TX_DRIVER != 0 )
{
/* The driver has taken ownership of the Network Buffer. */
*ppxNetworkBuffer = NULL;
}
#endif
}
return xSendLength;
}
/*-----------------------------------------------------------*/
/**
* @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 prvTCPSendSpecialPacketHelper( NetworkBufferDescriptor_t * pxNetworkBuffer,
uint8_t ucTCPFlags )
{
BaseType_t xReturn = pdTRUE;
#if ( ipconfigIGNORE_UNKNOWN_PACKETS == 1 )
/* Configured to ignore unknown packets just suppress a compiler warning. */
( void ) pxNetworkBuffer;
( void ) ucTCPFlags;
#else
{
switch( uxIPHeaderSizePacket( pxNetworkBuffer ) )
{
#if ( ipconfigUSE_IPv4 != 0 )
case ipSIZE_OF_IPv4_HEADER:
xReturn = prvTCPSendSpecialPktHelper_IPV4( pxNetworkBuffer, ucTCPFlags );
break;
#endif /* ( ipconfigUSE_IPv4 != 0 ) */
#if ( ipconfigUSE_IPv6 != 0 )
case ipSIZE_OF_IPv6_HEADER:
xReturn = prvTCPSendSpecialPktHelper_IPV6( pxNetworkBuffer, ucTCPFlags );
break;
#endif /* ( ipconfigUSE_IPv6 != 0 ) */
default:
xReturn = pdFAIL;
break;
}
}
#endif /* !ipconfigIGNORE_UNKNOWN_PACKETS */
/* The packet was not consumed. */
return xReturn;
}
/*-----------------------------------------------------------*/
/**
* @brief A "challenge ACK" is as per https://tools.ietf.org/html/rfc5961#section-3.2,
* case #3. In summary, an RST was received with a sequence number that is
* unexpected but still within the window.
*
* @param[in] pxNetworkBuffer The network buffer descriptor with the packet.
*
* @return Returns the value back from #prvTCPSendSpecialPacketHelper.
*/
BaseType_t prvTCPSendChallengeAck( NetworkBufferDescriptor_t * pxNetworkBuffer )
{
return prvTCPSendSpecialPacketHelper( pxNetworkBuffer, tcpTCP_FLAG_ACK );
}
/*-----------------------------------------------------------*/
/**
* @brief Send a RST (Reset) to peer in case the packet cannot be handled.
*
* @param[in] pxNetworkBuffer The network buffer descriptor with the packet.
*
* @return Returns the value back from #prvTCPSendSpecialPacketHelper.
*/
BaseType_t prvTCPSendReset( NetworkBufferDescriptor_t * pxNetworkBuffer )
{
return prvTCPSendSpecialPacketHelper( pxNetworkBuffer,
( uint8_t ) tcpTCP_FLAG_ACK | ( uint8_t ) tcpTCP_FLAG_RST );
}
/*-----------------------------------------------------------*/
#endif /* ipconfigUSE_TCP == 1 */
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