blob: 22e7bec7add0fb8c719d5fe341031f879a5a0213 [file] [log] [blame]
/*
* FreeRTOS+TCP 2.2.x Labs copy
* Copyright (C) 2017 Amazon.com, Inc. or its affiliates. All Rights Reserved.
*
* Permission is hereby granted, free of charge, to any person obtaining a copy of
* this software and associated documentation files (the "Software"), to deal in
* the Software without restriction, including without limitation the rights to
* use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
* the Software, and to permit persons to whom the Software is furnished to do so,
* subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in all
* copies or substantial portions of the Software.
*
* 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
*/
/*
* FreeRTOS_TCP_IP.c
* Module which handles the TCP connections 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 "FreeRTOS_UDP_IP.h"
#include "FreeRTOS_TCP_IP.h"
#include "FreeRTOS_DHCP.h"
#include "NetworkInterface.h"
#include "NetworkBufferManagement.h"
#include "FreeRTOS_ARP.h"
#include "FreeRTOS_TCP_WIN.h"
/* Just make sure the contents doesn't get compiled if TCP is not enabled. */
#if ipconfigUSE_TCP == 1
/* This compile-time test was moved to here because some macro's
were unknown within 'FreeRTOSIPConfigDefaults.h'. It tests whether
the defined MTU size can contain at least a complete TCP packet. */
#if ( ( ipconfigTCP_MSS + ipSIZE_OF_IPv4_HEADER + ipSIZE_OF_TCP_HEADER ) > ipconfigNETWORK_MTU )
#error The ipconfigTCP_MSS setting in FreeRTOSIPConfig.h is too large.
#endif
/*
* The meaning of the TCP flags:
*/
#define ipTCP_FLAG_FIN 0x0001u /* No more data from sender */
#define ipTCP_FLAG_SYN 0x0002u /* Synchronize sequence numbers */
#define ipTCP_FLAG_RST 0x0004u /* Reset the connection */
#define ipTCP_FLAG_PSH 0x0008u /* Push function: please push buffered data to the recv application */
#define ipTCP_FLAG_ACK 0x0010u /* Acknowledgment field is significant */
#define ipTCP_FLAG_URG 0x0020u /* Urgent pointer field is significant */
#define ipTCP_FLAG_ECN 0x0040u /* ECN-Echo */
#define ipTCP_FLAG_CWR 0x0080u /* Congestion Window Reduced */
#define ipTCP_FLAG_NS 0x0100u /* ECN-nonce concealment protection */
#define ipTCP_FLAG_RSV 0x0E00u /* Reserved, keep 0 */
/* A mask to filter all protocol flags. */
#define ipTCP_FLAG_CTRL 0x001Fu
/*
* A few values of the TCP options:
*/
#define TCP_OPT_END 0u /* End of TCP options list */
#define TCP_OPT_NOOP 1u /* "No-operation" TCP option */
#define TCP_OPT_MSS 2u /* Maximum segment size TCP option */
#define TCP_OPT_WSOPT 3u /* TCP Window Scale Option (3-byte long) */
#define TCP_OPT_SACK_P 4u /* Advertize that SACK is permitted */
#define TCP_OPT_SACK_A 5u /* SACK option with first/last */
#define TCP_OPT_TIMESTAMP 8u /* Time-stamp option */
#define TCP_OPT_MSS_LEN 4u /* Length of TCP MSS option. */
#define TCP_OPT_WSOPT_LEN 3u /* Length of TCP WSOPT option. */
#define TCP_OPT_TIMESTAMP_LEN 10 /* fixed length of the time-stamp option */
#ifndef ipconfigTCP_ACK_EARLIER_PACKET
#define ipconfigTCP_ACK_EARLIER_PACKET 1
#endif
/*
* The macro NOW_CONNECTED() is use to determine if the connection makes a
* transition from connected to non-connected and vice versa.
* NOW_CONNECTED() returns true when the status has one of these values:
* eESTABLISHED, eFIN_WAIT_1, eFIN_WAIT_2, eCLOSING, eLAST_ACK, eTIME_WAIT
* Technically the connection status is closed earlier, but the library wants
* to prevent that the socket will be deleted before the last ACK has been
* and thus causing a 'RST' packet on either side.
*/
#define NOW_CONNECTED( status )\
( ( status >= eESTABLISHED ) && ( status != eCLOSE_WAIT ) )
/*
* The highest 4 bits in the TCP offset byte indicate the total length of the
* TCP header, divided by 4.
*/
#define VALID_BITS_IN_TCP_OFFSET_BYTE ( 0xF0u )
/*
* Acknowledgements to TCP data packets may be delayed as long as more is being expected.
* A normal delay would be 200ms. Here a much shorter delay of 20 ms is being used to
* gain performance.
*/
#define DELAYED_ACK_SHORT_DELAY_MS ( 2 )
#define DELAYED_ACK_LONGER_DELAY_MS ( 20 )
/*
* The MSS (Maximum Segment Size) will be taken as large as possible. However, packets with
* an MSS of 1460 bytes won't be transported through the internet. The MSS will be reduced
* to 1400 bytes.
*/
#define REDUCED_MSS_THROUGH_INTERNET ( 1400 )
/*
* When there are no TCP options, the TCP offset equals 20 bytes, which is stored as
* the number 5 (words) in the higher niblle of the TCP-offset byte.
*/
#define TCP_OFFSET_LENGTH_BITS ( 0xf0u )
#define TCP_OFFSET_STANDARD_LENGTH ( 0x50u )
/*
* Each TCP socket is checked regularly to see if it can send data packets.
* By default, the maximum number of packets sent during one check is limited to 8.
* This amount may be further limited by setting the socket's TX window size.
*/
#if( !defined( SEND_REPEATED_COUNT ) )
#define SEND_REPEATED_COUNT ( 8 )
#endif /* !defined( SEND_REPEATED_COUNT ) */
/*
* Define a maximum perdiod of time (ms) to leave a TCP-socket unattended.
* When a TCP timer expires, retries and keep-alive messages will be checked.
*/
#ifndef tcpMAXIMUM_TCP_WAKEUP_TIME_MS
#define tcpMAXIMUM_TCP_WAKEUP_TIME_MS 20000u
#endif
/*
* The names of the different TCP states may be useful in logging.
*/
#if( ( ipconfigHAS_DEBUG_PRINTF != 0 ) || ( ipconfigHAS_PRINTF != 0 ) )
static const char *pcStateNames[] = {
"eCLOSED",
"eTCP_LISTEN",
"eCONNECT_SYN",
"eSYN_FIRST",
"eSYN_RECEIVED",
"eESTABLISHED",
"eFIN_WAIT_1",
"eFIN_WAIT_2",
"eCLOSE_WAIT",
"eCLOSING",
"eLAST_ACK",
"eTIME_WAIT",
"eUNKNOWN",
};
#endif /* ( ipconfigHAS_DEBUG_PRINTF != 0 ) || ( ipconfigHAS_PRINTF != 0 ) */
/*
* Returns true if the socket must be checked. Non-active sockets are waiting
* for user action, either connect() or close().
*/
static BaseType_t prvTCPSocketIsActive( UBaseType_t uxStatus );
/*
* Either sends a SYN or calls prvTCPSendRepeated (for regular messages).
*/
static int32_t prvTCPSendPacket( FreeRTOS_Socket_t *pxSocket );
/*
* Try to send a series of messages.
*/
static int32_t prvTCPSendRepeated( FreeRTOS_Socket_t *pxSocket, NetworkBufferDescriptor_t **ppxNetworkBuffer );
/*
* Return or send a packet to the other party.
*/
static void prvTCPReturnPacket( FreeRTOS_Socket_t *pxSocket, NetworkBufferDescriptor_t *pxNetworkBuffer,
uint32_t ulLen, BaseType_t xReleaseAfterSend );
/*
* Initialise the data structures which keep track of the TCP windowing system.
*/
static void prvTCPCreateWindow( FreeRTOS_Socket_t *pxSocket );
/*
* Let ARP look-up the MAC-address of the peer and initialise the first SYN
* packet.
*/
static BaseType_t prvTCPPrepareConnect( FreeRTOS_Socket_t *pxSocket );
#if( ipconfigHAS_DEBUG_PRINTF != 0 )
/*
* For logging and debugging: make a string showing the TCP flags.
*/
static const char *prvTCPFlagMeaning( UBaseType_t xFlags);
#endif /* ipconfigHAS_DEBUG_PRINTF != 0 */
/*
* Parse the TCP option(s) received, if present.
*/
static void prvCheckOptions( FreeRTOS_Socket_t *pxSocket, NetworkBufferDescriptor_t *pxNetworkBuffer );
/*
* Identify and deal with a single TCP header option, advancing the pointer to
* the header. This function returns pdTRUE or pdFALSE depending on whether the
* caller should continue to parse more header options or break the loop.
*/
static BaseType_t prvSingleStepTCPHeaderOptions( const unsigned char ** const ppucPtr, const unsigned char ** const ppucLast, FreeRTOS_Socket_t ** const ppxSocket, TCPWindow_t ** const ppxTCPWindow);
/*
* Skip past TCP header options when doing Selective ACK, until there are no
* more options left.
*/
static void prvSkipPastRemainingOptions( const unsigned char ** const ppucPtr, FreeRTOS_Socket_t ** const ppxSocket, unsigned char * const ppucLen );
/*
* Set the initial properties in the options fields, like the preferred
* value of MSS and whether SACK allowed. Will be transmitted in the state
* 'eCONNECT_SYN'.
*/
static UBaseType_t prvSetSynAckOptions( FreeRTOS_Socket_t *pxSocket, TCPPacket_t * pxTCPPacket );
/*
* For anti-hang protection and TCP keep-alive messages. Called in two places:
* after receiving a packet and after a state change. The socket's alive timer
* may be reset.
*/
static void prvTCPTouchSocket( FreeRTOS_Socket_t *pxSocket );
/*
* Prepare an outgoing message, if anything has to be sent.
*/
static int32_t prvTCPPrepareSend( FreeRTOS_Socket_t *pxSocket, NetworkBufferDescriptor_t **ppxNetworkBuffer, UBaseType_t uxOptionsLength );
/*
* Calculate when this socket needs to be checked to do (re-)transmissions.
*/
static TickType_t prvTCPNextTimeout( FreeRTOS_Socket_t *pxSocket );
/*
* The API FreeRTOS_send() adds data to the TX stream. Add
* this data to the windowing system to it can be transmitted.
*/
static void prvTCPAddTxData( FreeRTOS_Socket_t *pxSocket );
/*
* Called to handle the closure of a TCP connection.
*/
static BaseType_t prvTCPHandleFin( FreeRTOS_Socket_t *pxSocket, NetworkBufferDescriptor_t *pxNetworkBuffer );
/*
* Called from prvTCPHandleState(). Find the TCP payload data and check and
* return its length.
*/
static BaseType_t prvCheckRxData( NetworkBufferDescriptor_t *pxNetworkBuffer, uint8_t **ppucRecvData );
/*
* Called from prvTCPHandleState(). Check if the payload data may be accepted.
* If so, it will be added to the socket's reception queue.
*/
static BaseType_t prvStoreRxData( FreeRTOS_Socket_t *pxSocket, uint8_t *pucRecvData,
NetworkBufferDescriptor_t *pxNetworkBuffer, uint32_t ulReceiveLength );
/*
* Set the TCP options (if any) for the outgoing packet.
*/
static UBaseType_t prvSetOptions( FreeRTOS_Socket_t *pxSocket, NetworkBufferDescriptor_t *pxNetworkBuffer );
/*
* Called from prvTCPHandleState() as long as the TCP status is eSYN_RECEIVED to
* eCONNECT_SYN.
*/
static BaseType_t prvHandleSynReceived( FreeRTOS_Socket_t *pxSocket, NetworkBufferDescriptor_t **ppxNetworkBuffer,
uint32_t ulReceiveLength, UBaseType_t uxOptionsLength );
/*
* Called from prvTCPHandleState() as long as the TCP status is eESTABLISHED.
*/
static BaseType_t prvHandleEstablished( FreeRTOS_Socket_t *pxSocket, NetworkBufferDescriptor_t **ppxNetworkBuffer,
uint32_t ulReceiveLength, UBaseType_t uxOptionsLength );
/*
* 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.
*/
static BaseType_t prvSendData( FreeRTOS_Socket_t *pxSocket, NetworkBufferDescriptor_t **ppxNetworkBuffer,
uint32_t ulReceiveLength, BaseType_t xSendLength );
/*
* The heart of all: check incoming packet for valid data and acks and do what
* is necessary in each state.
*/
static BaseType_t prvTCPHandleState( FreeRTOS_Socket_t *pxSocket, NetworkBufferDescriptor_t **ppxNetworkBuffer );
/*
* Common code for sending a TCP protocol control packet (i.e. no options, no
* payload, just flags).
*/
static BaseType_t prvTCPSendSpecialPacketHelper( NetworkBufferDescriptor_t *pxNetworkBuffer,
uint8_t ucTCPFlags );
/*
* 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.
*/
static BaseType_t prvTCPSendChallengeAck( NetworkBufferDescriptor_t *pxNetworkBuffer );
/*
* Reply to a peer with the RST flag on, in case a packet can not be handled.
*/
static BaseType_t prvTCPSendReset( NetworkBufferDescriptor_t *pxNetworkBuffer );
/*
* Set the initial value for MSS (Maximum Segment Size) to be used.
*/
static void prvSocketSetMSS( FreeRTOS_Socket_t *pxSocket );
/*
* Return either a newly created socket, or the current socket in a connected
* state (depends on the 'bReuseSocket' flag).
*/
static FreeRTOS_Socket_t *prvHandleListen( FreeRTOS_Socket_t *pxSocket, NetworkBufferDescriptor_t *pxNetworkBuffer );
/*
* After a listening socket receives a new connection, it may duplicate itself.
* The copying takes place in prvTCPSocketCopy.
*/
static BaseType_t prvTCPSocketCopy( FreeRTOS_Socket_t *pxNewSocket, FreeRTOS_Socket_t *pxSocket );
/*
* prvTCPStatusAgeCheck() will see if the socket has been in a non-connected
* state for too long. If so, the socket will be closed, and -1 will be
* returned.
*/
#if( ipconfigTCP_HANG_PROTECTION == 1 )
static BaseType_t prvTCPStatusAgeCheck( FreeRTOS_Socket_t *pxSocket );
#endif
static NetworkBufferDescriptor_t *prvTCPBufferResize( FreeRTOS_Socket_t *pxSocket, NetworkBufferDescriptor_t *pxNetworkBuffer,
int32_t lDataLen, UBaseType_t uxOptionsLength );
#if( ( ipconfigHAS_DEBUG_PRINTF != 0 ) || ( ipconfigHAS_PRINTF != 0 ) )
const char *FreeRTOS_GetTCPStateName( UBaseType_t ulState );
#endif
#if( ipconfigUSE_TCP_WIN != 0 )
static uint8_t prvWinScaleFactor( FreeRTOS_Socket_t *pxSocket );
#endif
/*
* Generate a randomized TCP Initial Sequence Number per RFC.
*/
extern uint32_t ulApplicationGetNextSequenceNumber( uint32_t ulSourceAddress,
uint16_t usSourcePort,
uint32_t ulDestinationAddress,
uint16_t usDestinationPort );
/*-----------------------------------------------------------*/
/* prvTCPSocketIsActive() returns true if the socket must be checked.
* Non-active sockets are waiting for user action, either connect()
* or close(). */
static BaseType_t prvTCPSocketIsActive( UBaseType_t uxStatus )
{
switch( uxStatus )
{
case eCLOSED:
case eCLOSE_WAIT:
case eFIN_WAIT_2:
case eCLOSING:
case eTIME_WAIT:
return pdFALSE;
default:
return pdTRUE;
}
}
/*-----------------------------------------------------------*/
#if( ipconfigTCP_HANG_PROTECTION == 1 )
static BaseType_t prvTCPStatusAgeCheck( FreeRTOS_Socket_t *pxSocket )
{
BaseType_t xResult;
switch( pxSocket->u.xTCP.ucTCPState )
{
case eESTABLISHED:
/* If the 'ipconfigTCP_KEEP_ALIVE' option is enabled, sockets in
state ESTABLISHED can be protected using keep-alive messages. */
xResult = pdFALSE;
break;
case eCLOSED:
case eTCP_LISTEN:
case eCLOSE_WAIT:
/* These 3 states may last for ever, up to the owner. */
xResult = pdFALSE;
break;
default:
/* All other (non-connected) states will get anti-hanging
protection. */
xResult = pdTRUE;
break;
}
if( xResult != pdFALSE )
{
/* How much time has past since the last active moment which is
defined as A) a state change or B) a packet has arrived. */
TickType_t xAge = xTaskGetTickCount( ) - pxSocket->u.xTCP.xLastActTime;
/* ipconfigTCP_HANG_PROTECTION_TIME is in units of seconds. */
if( xAge > ( ipconfigTCP_HANG_PROTECTION_TIME * configTICK_RATE_HZ ) )
{
#if( ipconfigHAS_DEBUG_PRINTF == 1 )
{
FreeRTOS_debug_printf( ( "Inactive socket closed: port %u rem %lxip:%u status %s\n",
pxSocket->usLocalPort,
pxSocket->u.xTCP.ulRemoteIP,
pxSocket->u.xTCP.usRemotePort,
FreeRTOS_GetTCPStateName( ( UBaseType_t ) pxSocket->u.xTCP.ucTCPState ) ) );
}
#endif /* ipconfigHAS_DEBUG_PRINTF */
/* Move to eCLOSE_WAIT, user may close the socket. */
vTCPStateChange( pxSocket, eCLOSE_WAIT );
/* When 'bPassQueued' true, this socket is an orphan until it
gets connected. */
if( pxSocket->u.xTCP.bits.bPassQueued != pdFALSE_UNSIGNED )
{
if( pxSocket->u.xTCP.bits.bReuseSocket == pdFALSE_UNSIGNED )
{
/* As it did not get connected, and the user can never
accept() it anymore, it will be deleted now. Called from
the IP-task, so it's safe to call the internal Close
function: vSocketClose(). */
vSocketClose( pxSocket );
}
/* Return a negative value to tell to inform the caller
xTCPTimerCheck()
that the socket got closed and may not be accessed anymore. */
xResult = -1;
}
}
}
return xResult;
}
/*-----------------------------------------------------------*/
#endif
/*
* As soon as a TCP socket timer expires, this function xTCPSocketCheck
* will be called (from xTCPTimerCheck)
* It can send a delayed ACK or new data
* Sequence of calling (normally) :
* IP-Task:
* xTCPTimerCheck() // Check all sockets ( declared in FreeRTOS_Sockets.c )
* xTCPSocketCheck() // Either send a delayed ACK or call prvTCPSendPacket()
* prvTCPSendPacket() // Either send a SYN or call prvTCPSendRepeated ( regular messages )
* prvTCPSendRepeated() // Send at most 8 messages on a row
* prvTCPReturnPacket() // Prepare for returning
* xNetworkInterfaceOutput() // Sends data to the NIC ( declared in portable/NetworkInterface/xxx )
*/
BaseType_t xTCPSocketCheck( FreeRTOS_Socket_t *pxSocket )
{
BaseType_t xResult = 0;
BaseType_t xReady = pdFALSE;
if( ( pxSocket->u.xTCP.ucTCPState >= eESTABLISHED ) && ( pxSocket->u.xTCP.txStream != NULL ) )
{
/* The API FreeRTOS_send() might have added data to the TX stream. Add
this data to the windowing system to it can be transmitted. */
prvTCPAddTxData( pxSocket );
}
#if ipconfigUSE_TCP_WIN == 1
{
if( pxSocket->u.xTCP.pxAckMessage != NULL )
{
/* The first task of this regular socket check is to send-out delayed
ACK's. */
if( pxSocket->u.xTCP.bits.bUserShutdown == pdFALSE_UNSIGNED )
{
/* Earlier data was received but not yet acknowledged. This
function is called when the TCP timer for the socket expires, the
ACK may be sent now. */
if( pxSocket->u.xTCP.ucTCPState != eCLOSED )
{
if( xTCPWindowLoggingLevel > 1 && ipconfigTCP_MAY_LOG_PORT( pxSocket->usLocalPort ) )
{
FreeRTOS_debug_printf( ( "Send[%u->%u] del ACK %lu SEQ %lu (len %u)\n",
pxSocket->usLocalPort,
pxSocket->u.xTCP.usRemotePort,
pxSocket->u.xTCP.xTCPWindow.rx.ulCurrentSequenceNumber - pxSocket->u.xTCP.xTCPWindow.rx.ulFirstSequenceNumber,
pxSocket->u.xTCP.xTCPWindow.ulOurSequenceNumber - pxSocket->u.xTCP.xTCPWindow.tx.ulFirstSequenceNumber,
ipSIZE_OF_IPv4_HEADER + ipSIZE_OF_TCP_HEADER ) );
}
prvTCPReturnPacket( pxSocket, pxSocket->u.xTCP.pxAckMessage, ipSIZE_OF_IPv4_HEADER + ipSIZE_OF_TCP_HEADER, ipconfigZERO_COPY_TX_DRIVER );
#if( ipconfigZERO_COPY_TX_DRIVER != 0 )
{
/* The ownership has been passed to the SEND routine,
clear the pointer to it. */
pxSocket->u.xTCP.pxAckMessage = NULL;
}
#endif /* ipconfigZERO_COPY_TX_DRIVER */
}
if( prvTCPNextTimeout( pxSocket ) > 1 )
{
/* Tell the code below that this function is ready. */
xReady = pdTRUE;
}
}
else
{
/* The user wants to perform an active shutdown(), skip sending
the delayed ACK. The function prvTCPSendPacket() will send the
FIN along with the ACK's. */
}
if( pxSocket->u.xTCP.pxAckMessage != NULL )
{
vReleaseNetworkBufferAndDescriptor( pxSocket->u.xTCP.pxAckMessage );
pxSocket->u.xTCP.pxAckMessage = NULL;
}
}
}
#endif /* ipconfigUSE_TCP_WIN */
if( xReady == pdFALSE )
{
/* The second task of this regular socket check is sending out data. */
if( ( pxSocket->u.xTCP.ucTCPState >= eESTABLISHED ) ||
( pxSocket->u.xTCP.ucTCPState == eCONNECT_SYN ) )
{
prvTCPSendPacket( pxSocket );
}
/* Set the time-out for the next wakeup for this socket. */
prvTCPNextTimeout( pxSocket );
#if( ipconfigTCP_HANG_PROTECTION == 1 )
{
/* In all (non-connected) states in which keep-alive messages can not be sent
the anti-hang protocol will close sockets that are 'hanging'. */
xResult = prvTCPStatusAgeCheck( pxSocket );
}
#endif
}
return xResult;
}
/*-----------------------------------------------------------*/
/*
* prvTCPSendPacket() will be called when the socket time-out has been reached.
* It is only called by xTCPSocketCheck().
*/
static int32_t prvTCPSendPacket( FreeRTOS_Socket_t *pxSocket )
{
int32_t lResult = 0;
UBaseType_t uxOptionsLength;
TCPPacket_t *pxTCPPacket;
NetworkBufferDescriptor_t *pxNetworkBuffer;
if( pxSocket->u.xTCP.ucTCPState != eCONNECT_SYN )
{
/* The connection is in s 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 %lxip:%u\n",
pxSocket->u.xTCP.ulRemoteIP, /* IP address of remote machine. */
pxSocket->u.xTCP.usRemotePort ) ); /* Port on remote machine. */
vTCPStateChange( pxSocket, eCLOSE_WAIT );
}
else if( ( pxSocket->u.xTCP.bits.bConnPrepared != pdFALSE_UNSIGNED ) || ( prvTCPPrepareConnect( pxSocket ) == pdTRUE ) )
{
/* 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. */
pxTCPPacket = ( TCPPacket_t * )pxSocket->u.xTCP.xPacket.u.ucLastPacket;
/* 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, pxTCPPacket );
/* Return the number of bytes to be sent. */
lResult = ( BaseType_t ) ( ipSIZE_OF_IPv4_HEADER + ipSIZE_OF_TCP_HEADER + uxOptionsLength );
/* 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 */
pxTCPPacket->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 );
}
}
/* Return the total number of bytes sent. */
return lResult;
}
/*-----------------------------------------------------------*/
/*
* 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.
*/
static 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;
}
/*-----------------------------------------------------------*/
/*
* Return (or send) a packet the 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.
*/
static void prvTCPReturnPacket( FreeRTOS_Socket_t *pxSocket, NetworkBufferDescriptor_t *pxNetworkBuffer, uint32_t ulLen, BaseType_t xReleaseAfterSend )
{
TCPPacket_t * pxTCPPacket;
IPHeader_t *pxIPHeader;
EthernetHeader_t *pxEthernetHeader;
uint32_t ulFrontSpace, ulSpace, ulSourceAddress, ulWinSize;
TCPWindow_t *pxTCPWindow;
NetworkBufferDescriptor_t xTempBuffer;
/* For sending, a pseudo network buffer will be used, as explained above. */
if( pxNetworkBuffer == NULL )
{
pxNetworkBuffer = &xTempBuffer;
#if( ipconfigUSE_LINKED_RX_MESSAGES != 0 )
{
xTempBuffer.pxNextBuffer = NULL;
}
#endif
xTempBuffer.pucEthernetBuffer = pxSocket->u.xTCP.xPacket.u.ucLastPacket;
xTempBuffer.xDataLength = sizeof( pxSocket->u.xTCP.xPacket.u.ucLastPacket );
xReleaseAfterSend = pdFALSE;
}
#if( ipconfigZERO_COPY_TX_DRIVER != 0 )
{
if( xReleaseAfterSend == pdFALSE )
{
pxNetworkBuffer = pxDuplicateNetworkBufferWithDescriptor( pxNetworkBuffer, ( BaseType_t ) pxNetworkBuffer->xDataLength );
if( pxNetworkBuffer == NULL )
{
FreeRTOS_debug_printf( ( "prvTCPReturnPacket: duplicate failed\n" ) );
}
xReleaseAfterSend = pdTRUE;
}
}
#endif /* ipconfigZERO_COPY_TX_DRIVER */
if( pxNetworkBuffer != NULL )
{
pxTCPPacket = ( TCPPacket_t * ) ( pxNetworkBuffer->pucEthernetBuffer );
pxIPHeader = &pxTCPPacket->xIPHeader;
pxEthernetHeader = &pxTCPPacket->xEthernetHeader;
/* Fill the packet, using hton translations. */
if( pxSocket != NULL )
{
/* Calculate the space in the RX buffer in order to advertise the
size of this socket's reception window. */
pxTCPWindow = &( pxSocket->u.xTCP.xTCPWindow );
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.usCurMSS ) && ( ulFrontSpace >= pxSocket->u.xTCP.usCurMSS ) )
{
ulSpace = pxSocket->u.xTCP.usCurMSS;
}
/* 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 > 0xfffcUL )
{
ulWinSize = 0xfffcUL;
}
pxTCPPacket->xTCPHeader.usWindow = FreeRTOS_htons( ( uint16_t ) ulWinSize );
#if( ipconfigHAS_DEBUG_PRINTF != 0 )
{
if( ipconfigTCP_MAY_LOG_PORT( pxSocket->usLocalPort ) != pdFALSE )
{
if( ( xTCPWindowLoggingLevel != 0 ) && ( pxSocket->u.xTCP.bits.bWinChange != pdFALSE_UNSIGNED ) )
{
size_t uxFrontSpace;
if(pxSocket->u.xTCP.rxStream != NULL)
{
uxFrontSpace = uxStreamBufferFrontSpace( pxSocket->u.xTCP.rxStream ) ;
}
else
{
uxFrontSpace = 0u;
}
FreeRTOS_debug_printf( ( "%s: %lxip:%u: [%lu < %lu] winSize %ld\n",
pxSocket->u.xTCP.bits.bLowWater ? "STOP" : "GO ",
pxSocket->u.xTCP.ulRemoteIP,
pxSocket->u.xTCP.usRemotePort,
pxSocket->u.xTCP.bits.bLowWater ? pxSocket->u.xTCP.uxLittleSpace : uxFrontSpace, pxSocket->u.xTCP.uxEnoughSpace,
(int32_t) ( pxTCPWindow->rx.ulHighestSequenceNumber - pxTCPWindow->rx.ulCurrentSequenceNumber ) ) );
}
}
}
#endif /* ipconfigHAS_DEBUG_PRINTF != 0 */
/* 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;
#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 an
responded to by acknowledging the last byte. */
pxSocket->u.xTCP.bits.bSendKeepAlive = pdFALSE_UNSIGNED;
pxSocket->u.xTCP.bits.bWaitKeepAlive = pdTRUE_UNSIGNED;
pxTCPPacket->xTCPHeader.ulSequenceNumber = pxSocket->u.xTCP.xTCPWindow.ulOurSequenceNumber - 1UL;
pxTCPPacket->xTCPHeader.ulSequenceNumber = FreeRTOS_htonl( pxTCPPacket->xTCPHeader.ulSequenceNumber );
}
else
#endif
{
pxTCPPacket->xTCPHeader.ulSequenceNumber = FreeRTOS_htonl( pxSocket->u.xTCP.xTCPWindow.ulOurSequenceNumber );
if( ( pxTCPPacket->xTCPHeader.ucTCPFlags & ( uint8_t ) ipTCP_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 + ipSIZE_OF_IPv4_HEADER ) );
if( ( pxTCPWindow->ulOurSequenceNumber + ulDataLen ) != pxTCPWindow->tx.ulFINSequenceNumber )
{
pxTCPPacket->xTCPHeader.ucTCPFlags &= ( ( uint8_t ) ~ipTCP_FLAG_FIN );
FreeRTOS_debug_printf( ( "Suppress FIN for %lu + %lu < %lu\n",
pxTCPWindow->ulOurSequenceNumber - pxTCPWindow->tx.ulFirstSequenceNumber,
ulDataLen,
pxTCPWindow->tx.ulFINSequenceNumber - pxTCPWindow->tx.ulFirstSequenceNumber ) );
}
}
}
/* Tell which sequence number is expected next time */
pxTCPPacket->xTCPHeader.ulAckNr = FreeRTOS_htonl( pxTCPWindow->rx.ulCurrentSequenceNumber );
}
else
{
/* Sending data without a socket, probably replying with a RST flag
Just swap the two sequence numbers. */
vFlip_32( pxTCPPacket->xTCPHeader.ulSequenceNumber, pxTCPPacket->xTCPHeader.ulAckNr );
}
pxIPHeader->ucTimeToLive = ( uint8_t ) ipconfigTCP_TIME_TO_LIVE;
pxIPHeader->usLength = FreeRTOS_htons( ulLen );
if( ( pxSocket == NULL ) || ( *ipLOCAL_IP_ADDRESS_POINTER == 0ul ) )
{
/* When pxSocket is NULL, this function is called by prvTCPSendReset()
and the IP-addresses must be swapped.
Also swap the IP-addresses in case the IP-tack doesn't have an
IP-address yet, i.e. when ( *ipLOCAL_IP_ADDRESS_POINTER == 0ul ). */
ulSourceAddress = pxIPHeader->ulDestinationIPAddress;
}
else
{
ulSourceAddress = *ipLOCAL_IP_ADDRESS_POINTER;
}
pxIPHeader->ulDestinationIPAddress = pxIPHeader->ulSourceIPAddress;
pxIPHeader->ulSourceIPAddress = ulSourceAddress;
vFlip_16( pxTCPPacket->xTCPHeader.usSourcePort, pxTCPPacket->xTCPHeader.usDestinationPort );
/* Just an increasing number. */
pxIPHeader->usIdentification = FreeRTOS_htons( usPacketIdentifier );
usPacketIdentifier++;
pxIPHeader->usFragmentOffset = 0u;
#if( ipconfigDRIVER_INCLUDED_TX_IP_CHECKSUM == 0 )
{
/* calculate the IP header checksum, in case the driver won't do that. */
pxIPHeader->usHeaderChecksum = 0x00u;
pxIPHeader->usHeaderChecksum = usGenerateChecksum( 0UL, ( uint8_t * ) &( pxIPHeader->ucVersionHeaderLength ), ipSIZE_OF_IPv4_HEADER );
pxIPHeader->usHeaderChecksum = ~FreeRTOS_htons( pxIPHeader->usHeaderChecksum );
/* calculate the TCP checksum for an outgoing packet. */
usGenerateProtocolChecksum( (uint8_t*)pxTCPPacket, pxNetworkBuffer->xDataLength, pdTRUE );
/* A calculated checksum of 0 must be inverted as 0 means the checksum
is disabled. */
if( pxTCPPacket->xTCPHeader.usChecksum == 0x00u )
{
pxTCPPacket->xTCPHeader.usChecksum = 0xffffU;
}
}
#endif
#if( ipconfigUSE_LINKED_RX_MESSAGES != 0 )
pxNetworkBuffer->pxNextBuffer = NULL;
#endif
/* Important: tell NIC driver how many bytes must be sent. */
pxNetworkBuffer->xDataLength = ulLen + ipSIZE_OF_ETH_HEADER;
/* Fill in the destination MAC addresses. */
memcpy( ( void * ) &( pxEthernetHeader->xDestinationAddress ), ( void * ) &( pxEthernetHeader->xSourceAddress ),
sizeof( pxEthernetHeader->xDestinationAddress ) );
/* The source MAC addresses is fixed to 'ipLOCAL_MAC_ADDRESS'. */
memcpy( ( void * ) &( pxEthernetHeader->xSourceAddress) , ( void * ) ipLOCAL_MAC_ADDRESS, ( size_t ) ipMAC_ADDRESS_LENGTH_BYTES );
#if defined( ipconfigETHERNET_MINIMUM_PACKET_BYTES )
{
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
/* Send! */
xNetworkInterfaceOutput( pxNetworkBuffer, xReleaseAfterSend );
if( xReleaseAfterSend == 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);
pxTCPPacket->xIPHeader.ulSourceIPAddress = pxTCPPacket->xIPHeader.ulDestinationIPAddress;
memcpy( pxEthernetHeader->xSourceAddress.ucBytes, pxEthernetHeader->xDestinationAddress.ucBytes, ( size_t ) ipMAC_ADDRESS_LENGTH_BYTES );
}
else
{
/* Nothing to do: the buffer has been passed to DMA and will be released after use */
}
} /* if( pxNetworkBuffer != NULL ) */
}
/*-----------------------------------------------------------*/
/*
* The SYN event is very important: the sequence numbers, which have a kind of
* random starting value, are being synchronised. The sliding window manager
* (in FreeRTOS_TCP_WIN.c) needs to know them, along with the Maximum Segment
* Size (MSS) in use.
*/
static void prvTCPCreateWindow( FreeRTOS_Socket_t *pxSocket )
{
if( xTCPWindowLoggingLevel )
FreeRTOS_debug_printf( ( "Limits (using): TCP Win size %lu Water %lu <= %lu <= %lu\n",
pxSocket->u.xTCP.uxRxWinSize * ipconfigTCP_MSS,
pxSocket->u.xTCP.uxLittleSpace ,
pxSocket->u.xTCP.uxEnoughSpace,
pxSocket->u.xTCP.uxRxStreamSize ) );
vTCPWindowCreate(
&pxSocket->u.xTCP.xTCPWindow,
ipconfigTCP_MSS * pxSocket->u.xTCP.uxRxWinSize,
ipconfigTCP_MSS * pxSocket->u.xTCP.uxTxWinSize,
pxSocket->u.xTCP.xTCPWindow.rx.ulCurrentSequenceNumber,
pxSocket->u.xTCP.xTCPWindow.ulOurSequenceNumber,
( uint32_t ) pxSocket->u.xTCP.usInitMSS );
}
/*-----------------------------------------------------------*/
/*
* 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.
*/
static BaseType_t prvTCPPrepareConnect( FreeRTOS_Socket_t *pxSocket )
{
TCPPacket_t *pxTCPPacket;
IPHeader_t *pxIPHeader;
eARPLookupResult_t eReturned;
uint32_t ulRemoteIP;
MACAddress_t xEthAddress;
BaseType_t xReturn = pdTRUE;
uint32_t ulInitialSequenceNumber = 0;
#if( ipconfigHAS_PRINTF != 0 )
{
/* Only necessary for nicer logging. */
memset( xEthAddress.ucBytes, '\0', sizeof( xEthAddress.ucBytes ) );
}
#endif /* ipconfigHAS_PRINTF != 0 */
ulRemoteIP = FreeRTOS_htonl( pxSocket->u.xTCP.ulRemoteIP );
/* Determine the ARP cache status for the requested IP address. */
eReturned = eARPGetCacheEntry( &( ulRemoteIP ), &( xEthAddress ) );
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 couldn't find the ARP address. */
pxSocket->u.xTCP.ucRepCount++;
FreeRTOS_debug_printf( ( "ARP for %lxip (using %lxip): rc=%d %02X:%02X:%02X %02X:%02X:%02X\n",
pxSocket->u.xTCP.ulRemoteIP,
FreeRTOS_htonl( ulRemoteIP ),
eReturned,
xEthAddress.ucBytes[ 0 ],
xEthAddress.ucBytes[ 1 ],
xEthAddress.ucBytes[ 2 ],
xEthAddress.ucBytes[ 3 ],
xEthAddress.ucBytes[ 4 ],
xEthAddress.ucBytes[ 5 ] ) );
/* And issue a (new) ARP request */
FreeRTOS_OutputARPRequest( ulRemoteIP );
xReturn = pdFALSE;
}
if( xReturn != pdFALSE )
{
/* Get a difficult-to-predict initial sequence number for this 4-tuple. */
ulInitialSequenceNumber = ulApplicationGetNextSequenceNumber( *ipLOCAL_IP_ADDRESS_POINTER,
pxSocket->usLocalPort,
pxSocket->u.xTCP.ulRemoteIP,
pxSocket->u.xTCP.usRemotePort );
/* Check for a random number generation error. */
if( 0 == ulInitialSequenceNumber )
{
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. */
pxTCPPacket = ( TCPPacket_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. */
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(). */
memcpy( &pxTCPPacket->xEthernetHeader.xSourceAddress, &xEthAddress, sizeof( xEthAddress ) );
/* 'ipIPv4_FRAME_TYPE' is already in network-byte-order. */
pxTCPPacket->xEthernetHeader.usFrameType = ipIPv4_FRAME_TYPE;
pxIPHeader->ucVersionHeaderLength = 0x45u;
pxIPHeader->usLength = FreeRTOS_htons( sizeof( TCPPacket_t ) - sizeof( pxTCPPacket->xEthernetHeader ) );
pxIPHeader->ucTimeToLive = ( uint8_t ) ipconfigTCP_TIME_TO_LIVE;
pxIPHeader->ucProtocol = ( uint8_t ) ipPROTOCOL_TCP;
/* Addresses and ports will be stored swapped because prvTCPReturnPacket
will swap them back while replying. */
pxIPHeader->ulDestinationIPAddress = *ipLOCAL_IP_ADDRESS_POINTER;
pxIPHeader->ulSourceIPAddress = FreeRTOS_htonl( pxSocket->u.xTCP.ulRemoteIP );
pxTCPPacket->xTCPHeader.usSourcePort = FreeRTOS_htons( pxSocket->u.xTCP.usRemotePort );
pxTCPPacket->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 = 0ul;
/* 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. */
pxTCPPacket->xTCPHeader.ucTCPOffset = 0x50u;
/* Only set the SYN flag. */
pxTCPPacket->xTCPHeader.ucTCPFlags = ipTCP_FLAG_SYN;
/* Set the values of usInitMSS / usCurMSS 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 );
}
return xReturn;
}
/*-----------------------------------------------------------*/
/* For logging and debugging: make a string showing the TCP flags
*/
#if( ipconfigHAS_DEBUG_PRINTF != 0 )
static const char *prvTCPFlagMeaning( UBaseType_t xFlags)
{
static char retString[10];
snprintf(retString, sizeof( retString ), "%c%c%c%c%c%c%c%c%c",
( xFlags & ipTCP_FLAG_FIN ) ? 'F' : '.', /* 0x0001: No more data from sender */
( xFlags & ipTCP_FLAG_SYN ) ? 'S' : '.', /* 0x0002: Synchronize sequence numbers */
( xFlags & ipTCP_FLAG_RST ) ? 'R' : '.', /* 0x0004: Reset the connection */
( xFlags & ipTCP_FLAG_PSH ) ? 'P' : '.', /* 0x0008: Push function: please push buffered data to the recv application */
( xFlags & ipTCP_FLAG_ACK ) ? 'A' : '.', /* 0x0010: Acknowledgment field is significant */
( xFlags & ipTCP_FLAG_URG ) ? 'U' : '.', /* 0x0020: Urgent pointer field is significant */
( xFlags & ipTCP_FLAG_ECN ) ? 'E' : '.', /* 0x0040: ECN-Echo */
( xFlags & ipTCP_FLAG_CWR ) ? 'C' : '.', /* 0x0080: Congestion Window Reduced */
( xFlags & ipTCP_FLAG_NS ) ? 'N' : '.'); /* 0x0100: ECN-nonce concealment protection */
return retString;
}
/*-----------------------------------------------------------*/
#endif /* ipconfigHAS_DEBUG_PRINTF */
/*
* Parse the TCP option(s) received, if present. It has already been verified
* that: ((pxTCPHeader->ucTCPOffset & 0xf0) > 0x50), meaning that the TP header
* is longer than the usual 20 (5 x 4) bytes.
*/
static void prvCheckOptions( FreeRTOS_Socket_t *pxSocket, NetworkBufferDescriptor_t *pxNetworkBuffer )
{
TCPPacket_t * pxTCPPacket;
TCPHeader_t * pxTCPHeader;
const unsigned char *pucPtr;
const unsigned char *pucLast;
TCPWindow_t *pxTCPWindow;
BaseType_t xShouldContinueLoop;
pxTCPPacket = ( TCPPacket_t * ) ( pxNetworkBuffer->pucEthernetBuffer );
pxTCPHeader = &pxTCPPacket->xTCPHeader;
/* A character pointer to iterate through the option data */
pucPtr = pxTCPHeader->ucOptdata;
pucLast = pucPtr + (((pxTCPHeader->ucTCPOffset >> 4) - 5) << 2);
pxTCPWindow = &pxSocket->u.xTCP.xTCPWindow;
/* Validate options size calculation. */
if( pucLast > ( pxNetworkBuffer->pucEthernetBuffer + pxNetworkBuffer->xDataLength ) )
{
return;
}
/* The comparison with pucLast is only necessary in case the option data are
corrupted, we don't like to run into invalid memory and crash. */
xShouldContinueLoop = pdTRUE;
while( ( pucPtr < pucLast ) && ( xShouldContinueLoop == pdTRUE ) )
{
xShouldContinueLoop = prvSingleStepTCPHeaderOptions( &pucPtr, &pucLast, &pxSocket, &pxTCPWindow );
}
}
/*-----------------------------------------------------------*/
static BaseType_t prvSingleStepTCPHeaderOptions( const unsigned char ** const ppucPtr, const unsigned char ** const ppucLast, FreeRTOS_Socket_t ** const ppxSocket, TCPWindow_t ** const ppxTCPWindow)
{
UBaseType_t uxNewMSS;
UBaseType_t xRemainingOptionsBytes = ( *ppucLast ) - ( *ppucPtr );
unsigned char ucLen;
if( ( *ppucPtr )[ 0 ] == TCP_OPT_END )
{
/* End of options. */
return pdFALSE;
}
if( ( *ppucPtr )[ 0 ] == TCP_OPT_NOOP)
{
/* NOP option, inserted to make the length a multiple of 4. */
( *ppucPtr )++;
return pdTRUE;
}
/* Any other well-formed option must be at least two bytes: the option
type byte followed by a length byte. */
if( xRemainingOptionsBytes < 2 )
{
return pdFALSE;
}
#if( ipconfigUSE_TCP_WIN != 0 )
else if( ( *ppucPtr )[ 0 ] == TCP_OPT_WSOPT )
{
/* Confirm that the option fits in the remaining buffer space. */
if( ( xRemainingOptionsBytes < TCP_OPT_WSOPT_LEN ) || ( ( *ppucPtr )[ 1 ] != TCP_OPT_WSOPT_LEN ) )
{
return pdFALSE;
}
( *ppxSocket )->u.xTCP.ucPeerWinScaleFactor = ( *ppucPtr )[ 2 ];
( *ppxSocket )->u.xTCP.bits.bWinScaling = pdTRUE_UNSIGNED;
( *ppucPtr ) += TCP_OPT_WSOPT_LEN;
}
#endif /* ipconfigUSE_TCP_WIN */
else if( ( *ppucPtr )[ 0 ] == TCP_OPT_MSS )
{
/* Confirm that the option fits in the remaining buffer space. */
if( ( xRemainingOptionsBytes < TCP_OPT_MSS_LEN )|| ( ( *ppucPtr )[ 1 ] != TCP_OPT_MSS_LEN ) )
{
return pdFALSE;
}
/* An MSS option with the correct option length. FreeRTOS_htons()
is not needed here because usChar2u16() already returns a host
endian number. */
uxNewMSS = usChar2u16( ( *ppucPtr ) + 2 );
if( ( *ppxSocket )->u.xTCP.usInitMSS != uxNewMSS )
{
/* Perform a basic check on the the new MSS. */
if( uxNewMSS == 0 )
{
return pdFALSE;
}
FreeRTOS_debug_printf( ( "MSS change %u -> %lu\n", ( *ppxSocket )->u.xTCP.usInitMSS, uxNewMSS ) );
}
if( ( *ppxSocket )->u.xTCP.usInitMSS > uxNewMSS )
{
/* our MSS was bigger than the MSS of the other party: adapt it. */
( *ppxSocket )->u.xTCP.bits.bMssChange = pdTRUE_UNSIGNED;
if( ( ( *ppxTCPWindow ) != NULL ) && ( ( *ppxSocket )->u.xTCP.usCurMSS > uxNewMSS ) )
{
/* The peer advertises a smaller MSS than this socket was
using. Use that as well. */
FreeRTOS_debug_printf( ( "Change mss %d => %lu\n", ( *ppxSocket )->u.xTCP.usCurMSS, uxNewMSS ) );
( *ppxSocket )->u.xTCP.usCurMSS = ( uint16_t ) uxNewMSS;
}
( *ppxTCPWindow )->xSize.ulRxWindowLength = ( ( uint32_t ) uxNewMSS ) * ( ( *ppxTCPWindow )->xSize.ulRxWindowLength / ( ( uint32_t ) uxNewMSS ) );
( *ppxTCPWindow )->usMSSInit = ( uint16_t ) uxNewMSS;
( *ppxTCPWindow )->usMSS = ( uint16_t ) uxNewMSS;
( *ppxSocket )->u.xTCP.usInitMSS = ( uint16_t ) uxNewMSS;
( *ppxSocket )->u.xTCP.usCurMSS = ( uint16_t ) uxNewMSS;
}
#if( ipconfigUSE_TCP_WIN != 1 )
/* Without scaled windows, MSS is the only interesting option. */
return pdFALSE;
#else
/* Or else we continue to check another option: selective ACK. */
( *ppucPtr ) += TCP_OPT_MSS_LEN;
#endif /* ipconfigUSE_TCP_WIN != 1 */
}
else
{
/* All other options have a length field, so that we easily
can skip past them. */
ucLen = ( *ppucPtr )[ 1 ];
if( ( ucLen < 2 ) || ( ucLen > xRemainingOptionsBytes ) )
{
/* If the length field is too small or too big, the options are
* malformed, don't process them further.
*/
return pdFALSE;
}
#if( ipconfigUSE_TCP_WIN == 1 )
{
/* Selective ACK: the peer has received a packet but it is missing
* earlier packets. At least this packet does not need retransmission
* anymore. ulTCPWindowTxSack( ) takes care of this administration.
*/
if( ( *ppucPtr )[0] == TCP_OPT_SACK_A )
{
ucLen -= 2;
( *ppucPtr ) += 2;
while( ucLen >= 8 )
{
prvSkipPastRemainingOptions( ppucPtr, ppxSocket, &ucLen );
}
/* ucLen should be 0 by now. */
}
}
#endif /* ipconfigUSE_TCP_WIN == 1 */
( *ppucPtr ) += ucLen;
}
return pdTRUE;
}
/*-----------------------------------------------------------*/
static void prvSkipPastRemainingOptions( const unsigned char ** const ppucPtr, FreeRTOS_Socket_t ** const ppxSocket, unsigned char * const pucLen )
{
uint32_t ulFirst = ulChar2u32( ( *ppucPtr ) );
uint32_t ulLast = ulChar2u32( ( *ppucPtr ) + 4 );
uint32_t ulCount = ulTCPWindowTxSack( &( *ppxSocket )->u.xTCP.xTCPWindow, ulFirst, ulLast );
/* ulTCPWindowTxSack( ) returns the number of bytes which have been acked
* starting from the head position. Advance the tail pointer in txStream.
*/
if( ( ( *ppxSocket )->u.xTCP.txStream != NULL ) && ( ulCount > 0 ) )
{
/* Just advancing the tail index, 'ulCount' bytes have been confirmed. */
uxStreamBufferGet( ( *ppxSocket )->u.xTCP.txStream, 0, NULL, ( size_t ) ulCount, pdFALSE );
( *ppxSocket )->xEventBits |= eSOCKET_SEND;
#if ipconfigSUPPORT_SELECT_FUNCTION == 1
{
if( ( *ppxSocket )->xSelectBits & eSELECT_WRITE )
{
/* The field 'xEventBits' is used to store regular socket events
* (at most 8), as well as 'select events', which will be left-shifted.
*/
( *ppxSocket )->xEventBits |= ( eSELECT_WRITE << SOCKET_EVENT_BIT_COUNT );
}
}
#endif
/* In case the socket owner has installed an OnSent handler, call it now.
*/
#if( ipconfigUSE_CALLBACKS == 1 )
{
if( ipconfigIS_VALID_PROG_ADDRESS( ( *ppxSocket )->u.xTCP.pxHandleSent ) )
{
( *ppxSocket )->u.xTCP.pxHandleSent( (Socket_t )( *ppxSocket ), ulCount );
}
}
#endif /* ipconfigUSE_CALLBACKS == 1 */
}
( *ppucPtr ) += 8;
( *pucLen ) -= 8;
}
/*-----------------------------------------------------------*/
#if( ipconfigUSE_TCP_WIN != 0 )
static uint8_t prvWinScaleFactor( 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.usInitMSS;
ucFactor = 0u;
while( uxWinSize > 0xfffful )
{
/* Divide by two and increase the binary factor by 1. */
uxWinSize >>= 1;
ucFactor++;
}
FreeRTOS_debug_printf( ( "prvWinScaleFactor: uxRxWinSize %lu MSS %lu Factor %u\n",
pxSocket->u.xTCP.uxRxWinSize,
pxSocket->u.xTCP.usInitMSS,
ucFactor ) );
return ucFactor;
}
#endif
/*-----------------------------------------------------------*/
/*
* When opening a TCP connection, while SYN's are being sent, the parties may
* communicate what MSS (Maximum Segment Size) they intend to use. MSS is the
* nett size of the payload, always smaller than MTU.
*/
static UBaseType_t prvSetSynAckOptions( FreeRTOS_Socket_t *pxSocket, TCPPacket_t * pxTCPPacket )
{
TCPHeader_t *pxTCPHeader = &pxTCPPacket->xTCPHeader;
uint16_t usMSS = pxSocket->u.xTCP.usInitMSS;
UBaseType_t uxOptionsLength;
/* We send out the TCP Maximum Segment Size option with our SYN[+ACK]. */
pxTCPHeader->ucOptdata[ 0 ] = ( uint8_t ) TCP_OPT_MSS;
pxTCPHeader->ucOptdata[ 1 ] = ( uint8_t ) TCP_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 ] = TCP_OPT_NOOP;
pxTCPHeader->ucOptdata[ 5 ] = ( uint8_t ) ( TCP_OPT_WSOPT );
pxTCPHeader->ucOptdata[ 6 ] = ( uint8_t ) ( TCP_OPT_WSOPT_LEN );
pxTCPHeader->ucOptdata[ 7 ] = ( uint8_t ) pxSocket->u.xTCP.ucMyWinScaleFactor;
uxOptionsLength = 8u;
}
#else
{
uxOptionsLength = 4u;
}
#endif
#if( ipconfigUSE_TCP_WIN == 0 )
{
return uxOptionsLength;
}
#else
{
pxTCPHeader->ucOptdata[ uxOptionsLength + 0 ] = TCP_OPT_NOOP;
pxTCPHeader->ucOptdata[ uxOptionsLength + 1 ] = TCP_OPT_NOOP;
pxTCPHeader->ucOptdata[ uxOptionsLength + 2 ] = TCP_OPT_SACK_P; /* 4: Sack-Permitted Option. */
pxTCPHeader->ucOptdata[ uxOptionsLength + 3 ] = 2; /* 2: length of this option. */
uxOptionsLength += 4u;
return uxOptionsLength; /* bytes, not words. */
}
#endif /* ipconfigUSE_TCP_WIN == 0 */
}
/*
* For anti-hanging protection and TCP keep-alive messages. Called in two
* places: after receiving a packet and after a state change. The socket's
* alive timer may be reset.
*/
static void prvTCPTouchSocket( FreeRTOS_Socket_t *pxSocket )
{
#if( ipconfigTCP_HANG_PROTECTION == 1 )
{
pxSocket->u.xTCP.xLastActTime = xTaskGetTickCount( );
}
#endif
#if( ipconfigTCP_KEEP_ALIVE == 1 )
{
pxSocket->u.xTCP.bits.bWaitKeepAlive = pdFALSE_UNSIGNED;
pxSocket->u.xTCP.bits.bSendKeepAlive = pdFALSE_UNSIGNED;
pxSocket->u.xTCP.ucKeepRepCount = 0u;
pxSocket->u.xTCP.xLastAliveTime = xTaskGetTickCount();
}
#endif
( void ) pxSocket;
}
/*-----------------------------------------------------------*/
/*
* Changing to a new state. Centralised here to do specific actions such as
* resetting the alive timer, calling the user's OnConnect handler to notify
* that a socket has got (dis)connected, and setting bit to unblock a call to
* FreeRTOS_select()
*/
void vTCPStateChange( FreeRTOS_Socket_t *pxSocket, enum eTCP_STATE eTCPState )
{
FreeRTOS_Socket_t *xParent = NULL;
BaseType_t bBefore = ( BaseType_t ) NOW_CONNECTED( pxSocket->u.xTCP.ucTCPState ); /* Was it connected ? */
BaseType_t bAfter = ( BaseType_t ) NOW_CONNECTED( eTCPState ); /* Is it connected now ? */
#if( ipconfigHAS_DEBUG_PRINTF != 0 )
BaseType_t xPreviousState = ( BaseType_t ) pxSocket->u.xTCP.ucTCPState;
#endif
#if( ipconfigUSE_CALLBACKS == 1 )
FreeRTOS_Socket_t *xConnected = NULL;
#endif
/* Has the connected status changed? */
if( bBefore != bAfter )
{
/* Is the socket connected now ? */
if( bAfter != pdFALSE )
{
/* if bPassQueued is true, this socket is an orphan until it gets connected. */
if( pxSocket->u.xTCP.bits.bPassQueued != pdFALSE_UNSIGNED )
{
/* Now that it is connected, find it's parent. */
if( pxSocket->u.xTCP.bits.bReuseSocket != pdFALSE_UNSIGNED )
{
xParent = pxSocket;
}
else
{
xParent = pxSocket->u.xTCP.pxPeerSocket;
configASSERT( xParent != NULL );
}
if( xParent != NULL )
{
if( xParent->u.xTCP.pxPeerSocket == NULL )
{
xParent->u.xTCP.pxPeerSocket = pxSocket;
}
xParent->xEventBits |= eSOCKET_ACCEPT;
#if( ipconfigSUPPORT_SELECT_FUNCTION == 1 )
{
/* Library support FreeRTOS_select(). Receiving a new
connection is being translated as a READ event. */
if( ( xParent->xSelectBits & eSELECT_READ ) != 0 )
{
xParent->xEventBits |= ( eSELECT_READ << SOCKET_EVENT_BIT_COUNT );
}
}
#endif
#if( ipconfigUSE_CALLBACKS == 1 )
{
if( ( ipconfigIS_VALID_PROG_ADDRESS( xParent->u.xTCP.pxHandleConnected ) != pdFALSE ) &&
( xParent->u.xTCP.bits.bReuseSocket == pdFALSE_UNSIGNED ) )
{
/* The listening socket does not become connected itself, in stead
a child socket is created.
Postpone a call the OnConnect event until the end of this function. */
xConnected = xParent;
}
}
#endif
}
/* Don't need to access the parent socket anymore, so the
reference 'pxPeerSocket' may be cleared. */
pxSocket->u.xTCP.pxPeerSocket = NULL;
pxSocket->u.xTCP.bits.bPassQueued = pdFALSE_UNSIGNED;
/* When true, this socket may be returned in a call to accept(). */
pxSocket->u.xTCP.bits.bPassAccept = pdTRUE_UNSIGNED;
}
else
{
pxSocket->xEventBits |= eSOCKET_CONNECT;
#if( ipconfigSUPPORT_SELECT_FUNCTION == 1 )
{
if( pxSocket->xSelectBits & eSELECT_WRITE )
{
pxSocket->xEventBits |= ( eSELECT_WRITE << SOCKET_EVENT_BIT_COUNT );
}
}
#endif
}
}
else /* bAfter == pdFALSE, connection is closed. */
{
/* Notify/wake-up the socket-owner by setting a semaphore. */
pxSocket->xEventBits |= eSOCKET_CLOSED;
#if( ipconfigSUPPORT_SELECT_FUNCTION == 1 )
{
if( ( pxSocket->xSelectBits & eSELECT_EXCEPT ) != 0 )
{
pxSocket->xEventBits |= ( eSELECT_EXCEPT << SOCKET_EVENT_BIT_COUNT );
}
}
#endif
}
#if( ipconfigUSE_CALLBACKS == 1 )
{
if( ( ipconfigIS_VALID_PROG_ADDRESS( pxSocket->u.xTCP.pxHandleConnected ) != pdFALSE ) && ( xConnected == NULL ) )
{
/* The 'connected' state has changed, call the user handler. */
xConnected = pxSocket;
}
}
#endif /* ipconfigUSE_CALLBACKS */
if( prvTCPSocketIsActive( ( UBaseType_t ) pxSocket->u.xTCP.ucTCPState ) == pdFALSE )
{
/* Now the socket isn't in an active state anymore so it
won't need further attention of the IP-task.
Setting time-out to zero means that the socket won't get checked during
timer events. */
pxSocket->u.xTCP.usTimeout = 0u;
}
}
else
{
if( eTCPState == eCLOSED )
{
/* Socket goes to status eCLOSED because of a RST.
When nobody owns the socket yet, delete it. */
if( ( pxSocket->u.xTCP.bits.bPassQueued != pdFALSE_UNSIGNED ) ||
( pxSocket->u.xTCP.bits.bPassAccept != pdFALSE_UNSIGNED ) )
{
FreeRTOS_debug_printf( ( "vTCPStateChange: Closing socket\n" ) );
if( pxSocket->u.xTCP.bits.bReuseSocket == pdFALSE_UNSIGNED )
{
FreeRTOS_closesocket( pxSocket );
}
}
}
}
/* Fill in the new state. */
pxSocket->u.xTCP.ucTCPState = ( uint8_t ) eTCPState;
/* touch the alive timers because moving to another state. */
prvTCPTouchSocket( pxSocket );
#if( ipconfigHAS_DEBUG_PRINTF == 1 )
{
if( ( xTCPWindowLoggingLevel >= 0 ) && ( ipconfigTCP_MAY_LOG_PORT( pxSocket->usLocalPort ) != pdFALSE ) )
FreeRTOS_debug_printf( ( "Socket %d -> %lxip:%u State %s->%s\n",
pxSocket->usLocalPort,
pxSocket->u.xTCP.ulRemoteIP,
pxSocket->u.xTCP.usRemotePort,
FreeRTOS_GetTCPStateName( ( UBaseType_t ) xPreviousState ),
FreeRTOS_GetTCPStateName( ( UBaseType_t ) eTCPState ) ) );
}
#endif /* ipconfigHAS_DEBUG_PRINTF */
#if( ipconfigUSE_CALLBACKS == 1 )
{
if( xConnected != NULL )
{
/* The 'connected' state has changed, call the OnConnect handler of the parent. */
xConnected->u.xTCP.pxHandleConnected( ( Socket_t ) xConnected, bAfter );
}
}
#endif
if( xParent != NULL )
{
vSocketWakeUpUser( xParent );
}
}
/*-----------------------------------------------------------*/
static NetworkBufferDescriptor_t *prvTCPBufferResize( FreeRTOS_Socket_t *pxSocket, NetworkBufferDescriptor_t *pxNetworkBuffer,
int32_t lDataLen, UBaseType_t uxOptionsLength )
{
NetworkBufferDescriptor_t *pxReturn;
int32_t lNeeded;
BaseType_t xResize;
if( xBufferAllocFixedSize != pdFALSE )
{
/* Network buffers are created with a fixed size and can hold the largest
MTU. */
lNeeded = ( int32_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. */
xResize = ( pxNetworkBuffer == NULL );
}
else
{
/* Network buffers are created with a variable size. See if it must
grow. */
lNeeded = FreeRTOS_max_int32( ( int32_t ) sizeof( pxSocket->u.xTCP.xPacket.u.ucLastPacket ),
( int32_t ) ( ipSIZE_OF_ETH_HEADER + ipSIZE_OF_IPv4_HEADER + ipSIZE_OF_TCP_HEADER + uxOptionsLength ) + lDataLen );
/* In case we were called from a TCP timer event, a buffer must be
created. Otherwise, test 'xDataLength' of the provided buffer. */
xResize = ( pxNetworkBuffer == NULL ) || ( pxNetworkBuffer->xDataLength < (size_t)lNeeded );
}
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( ( uint32_t ) lNeeded, 0u );
if( pxReturn != NULL )
{
/* Set the actual packet size, in case the returned buffer is larger. */
pxReturn->xDataLength = lNeeded;
/* Copy the existing data to the new created buffer. */
if( pxNetworkBuffer )
{
/* Either from the previous buffer... */
memcpy( pxReturn->pucEthernetBuffer, pxNetworkBuffer->pucEthernetBuffer, pxNetworkBuffer->xDataLength );
/* ...and release it. */
vReleaseNetworkBufferAndDescriptor( pxNetworkBuffer );
}
else
{
/* Or from the socket field 'xTCP.xPacket'. */
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. */
pxReturn = pxNetworkBuffer;
/* Thanks to Andrey Ivanov from swissEmbedded for reporting that the
xDataLength member must get the correct length too! */
pxNetworkBuffer->xDataLength = ( size_t ) ( ipSIZE_OF_ETH_HEADER + ipSIZE_OF_IPv4_HEADER + ipSIZE_OF_TCP_HEADER + uxOptionsLength ) + ( size_t ) lDataLen;
}
return pxReturn;
}
/*-----------------------------------------------------------*/
/*
* Prepare an outgoing message, in case anything has to be sent.
*/
static int32_t prvTCPPrepareSend( FreeRTOS_Socket_t *pxSocket, NetworkBufferDescriptor_t **ppxNetworkBuffer, UBaseType_t uxOptionsLength )
{
int32_t lDataLen;
uint8_t *pucEthernetBuffer, *pucSendData;
TCPPacket_t *pxTCPPacket;
size_t uxOffset;
uint32_t ulDataGot, ulDistance;
TCPWindow_t *pxTCPWindow;
NetworkBufferDescriptor_t *pxNewBuffer;
int32_t lStreamPos;
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;
}
pxTCPPacket = ( TCPPacket_t * ) ( pucEthernetBuffer );
pxTCPWindow = &pxSocket->u.xTCP.xTCPWindow;
lDataLen = 0;
lStreamPos = 0;
pxTCPPacket->xTCPHeader.ucTCPFlags |= ipTCP_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.usCurMSS > 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;
pxTCPPacket = ( TCPPacket_t * ) ( pucEthernetBuffer );
pucSendData = pucEthernetBuffer + ipSIZE_OF_ETH_HEADER + ipSIZE_OF_IPv4_HEADER + 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 %lu offs %lu only %lu != %lu\n",
lStreamPos, uxOffset, ulDataGot, 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 ) && ( pxSocket->u.xTCP.bits.bFinSent == 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 %lu <= %lu (%lu <= %lu <= %lu)\n", ulDataGot, ulDistance,
uxTail, uxMid, uxHead ) );
}
#endif
/* Although the socket sends a FIN, it will stay in
ESTABLISHED until all current data has been received or
delivered. */
pxTCPPacket->xTCPHeader.ucTCPFlags |= ipTCP_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.ucTCPState == 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;
pxTCPPacket->xTCPHeader.ucTCPFlags |= ipTCP_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 )
{
FreeRTOS_debug_printf( ( "keep-alive: giving up %lxip:%u\n",
pxSocket->u.xTCP.ulRemoteIP, /* 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 * configTICK_RATE_HZ );
if( pxSocket->u.xTCP.ucKeepRepCount )
{
xMax = ( 3u * configTICK_RATE_HZ );
}
if( xAge > xMax )
{
pxSocket->u.xTCP.xLastAliveTime = xTaskGetTickCount( );
if( xTCPWindowLoggingLevel )
FreeRTOS_debug_printf( ( "keep-alive: %lxip:%u count %u\n",
pxSocket->u.xTCP.ulRemoteIP,
pxSocket->u.xTCP.usRemotePort,
pxSocket->u.xTCP.ucKeepRepCount ) );
pxSocket->u.xTCP.bits.bSendKeepAlive = pdTRUE_UNSIGNED;
pxSocket->u.xTCP.usTimeout = ( ( uint16_t ) pdMS_TO_TICKS( 2500 ) );
pxSocket->u.xTCP.ucKeepRepCount++;
}
}
}
#endif /* ipconfigTCP_KEEP_ALIVE */
}
/* 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 ) )
{
pxTCPPacket->xTCPHeader.ucTCPFlags &= ( ( uint8_t ) ~ipTCP_FLAG_PSH );
pxTCPPacket->xTCPHeader.ucTCPOffset = ( uint8_t )( ( ipSIZE_OF_TCP_HEADER + uxOptionsLength ) << 2 );
pxTCPPacket->xTCPHeader.ucTCPFlags |= ( uint8_t ) ipTCP_FLAG_ACK;
if( lDataLen != 0l )
{
pxTCPPacket->xTCPHeader.ucTCPFlags |= ( uint8_t ) ipTCP_FLAG_PSH;
}
lDataLen += ( int32_t ) ( ipSIZE_OF_IPv4_HEADER + ipSIZE_OF_TCP_HEADER + uxOptionsLength );
}
return lDataLen;
}
/*-----------------------------------------------------------*/
/*
* Calculate after how much time this socket needs to be checked again.
*/
static TickType_t prvTCPNextTimeout ( FreeRTOS_Socket_t *pxSocket )
{
TickType_t ulDelayMs = ( TickType_t ) tcpMAXIMUM_TCP_WAKEUP_TIME_MS;
if( pxSocket->u.xTCP.ucTCPState == eCONNECT_SYN )
{
/* The socket is actively connecting to a peer. */
if( pxSocket->u.xTCP.bits.bConnPrepared )
{
/* Ethernet address has been found, use progressive timeout for
active connect(). */
if( pxSocket->u.xTCP.ucRepCount < 3u )
{
ulDelayMs = ( 3000UL << ( pxSocket->u.xTCP.ucRepCount - 1u ) );
}
else
{
ulDelayMs = 11000UL;
}
}
else
{
/* Still in the ARP phase: check every half second. */
ulDelayMs = 500UL;
}
FreeRTOS_debug_printf( ( "Connect[%lxip:%u]: next timeout %u: %lu ms\n",
pxSocket->u.xTCP.ulRemoteIP, pxSocket->u.xTCP.usRemotePort,
pxSocket->u.xTCP.ucRepCount, ulDelayMs ) );
pxSocket->u.xTCP.usTimeout = ( uint16_t )pdMS_TO_MIN_TICKS( ulDelayMs );
}
else if( pxSocket->u.xTCP.usTimeout == 0u )
{
/* Let the sliding window mechanism decide what time-out is appropriate. */
BaseType_t xResult = xTCPWindowTxHasData( &pxSocket->u.xTCP.xTCPWindow, pxSocket->u.xTCP.ulWindowSize, &ulDelayMs );
if( ulDelayMs == 0u )
{
if( xResult != ( BaseType_t )0 )
{
ulDelayMs = 1UL;
}
else
{
ulDelayMs = tcpMAXIMUM_TCP_WAKEUP_TIME_MS;
}
}
else
{
/* ulDelayMs contains the time to wait before a re-transmission. */
}
pxSocket->u.xTCP.usTimeout = ( uint16_t )pdMS_TO_MIN_TICKS( ulDelayMs );
}
else
{
/* field '.usTimeout' has already been set (by the
keep-alive/delayed-ACK mechanism). */
}
/* Return the number of clock ticks before the timer expires. */
return ( TickType_t ) pxSocket->u.xTCP.usTimeout;
}
/*-----------------------------------------------------------*/
static 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 );
}
}
}
/*-----------------------------------------------------------*/
/*
* prvTCPHandleFin() will be called to handle socket closure
* The Closure starts when either a FIN has been received and accepted,
* Or when the socket has sent a FIN flag to the peer
* Before being called, it has been checked that both reception and transmission
* are complete.
*/
static BaseType_t prvTCPHandleFin( FreeRTOS_Socket_t *pxSocket, NetworkBufferDescriptor_t *pxNetworkBuffer )
{
TCPPacket_t *pxTCPPacket = ( TCPPacket_t * ) ( pxNetworkBuffer->pucEthernetBuffer );
TCPHeader_t *pxTCPHeader = &pxTCPPacket->xTCPHeader;
uint8_t ucTCPFlags = pxTCPHeader->ucTCPFlags;
TCPWindow_t *pxTCPWindow = &pxSocket->u.xTCP.xTCPWindow;
BaseType_t xSendLength = 0;
uint32_t ulAckNr = FreeRTOS_ntohl( pxTCPHeader->ulAckNr );
if( ( ucTCPFlags & ipTCP_FLAG_FIN ) != 0u )
{
pxTCPWindow->rx.ulCurrentSequenceNumber = pxTCPWindow->rx.ulFINSequenceNumber + 1u;
}
if( pxSocket->u.xTCP.bits.bFinSent == pdFALSE_UNSIGNED )
{
/* We haven't yet replied with a FIN, do so now. */
pxTCPWindow->tx.ulFINSequenceNumber = pxTCPWindow->tx.ulCurrentSequenceNumber;
pxSocket->u.xTCP.bits.bFinSent = pdTRUE_UNSIGNED;
}
else
{
/* We did send a FIN already, see if it's ACK'd. */
if( ulAckNr == pxTCPWindow->tx.ulFINSequenceNumber + 1u )
{
pxSocket->u.xTCP.bits.bFinAcked = pdTRUE_UNSIGNED;
}
}
if( pxSocket->u.xTCP.bits.bFinAcked == pdFALSE_UNSIGNED )
{
pxTCPWindow->tx.ulCurrentSequenceNumber = pxTCPWindow->tx.ulFINSequenceNumber;
pxTCPHeader->ucTCPFlags = ipTCP_FLAG_ACK | ipTCP_FLAG_FIN;
/* And wait for the final ACK. */
vTCPStateChange( pxSocket, eLAST_ACK );
}
else
{
/* Our FIN has been ACK'd, the outgoing sequence number is now fixed. */
pxTCPWindow->tx.ulCurrentSequenceNumber = pxTCPWindow->tx.ulFINSequenceNumber + 1u;
if( pxSocket->u.xTCP.bits.bFinRecv == pdFALSE_UNSIGNED )
{
/* We have sent out a FIN but the peer hasn't replied with a FIN
yet. Do nothing for the moment. */
pxTCPHeader->ucTCPFlags = 0u;
}
else
{
if( pxSocket->u.xTCP.bits.bFinLast == pdFALSE_UNSIGNED )
{
/* This is the third of the three-way hand shake: the last
ACK. */
pxTCPHeader->ucTCPFlags = ipTCP_FLAG_ACK;
}
else
{
/* The other party started the closure, so we just wait for the
last ACK. */
pxTCPHeader->ucTCPFlags = 0u;
}
/* And wait for the user to close this socket. */
vTCPStateChange( pxSocket, eCLOSE_WAIT );
}
}
pxTCPWindow->ulOurSequenceNumber = pxTCPWindow->tx.ulCurrentSequenceNumber;
if( pxTCPHeader->ucTCPFlags != 0u )
{
xSendLength = ( BaseType_t ) ( ipSIZE_OF_IPv4_HEADER + ipSIZE_OF_TCP_HEADER + pxTCPWindow->ucOptionLength );
}
pxTCPHeader->ucTCPOffset = ( uint8_t ) ( ( ipSIZE_OF_TCP_HEADER + pxTCPWindow->ucOptionLength ) << 2 );
if( xTCPWindowLoggingLevel != 0 )
{
FreeRTOS_debug_printf( ( "TCP: send FIN+ACK (ack %lu, cur/nxt %lu/%lu) ourSeqNr %lu | Rx %lu\n",
ulAckNr - pxTCPWindow->tx.ulFirstSequenceNumber,
pxTCPWindow->tx.ulCurrentSequenceNumber - pxTCPWindow->tx.ulFirstSequenceNumber,
pxTCPWindow->ulNextTxSequenceNumber - pxTCPWindow->tx.ulFirstSequenceNumber,
pxTCPWindow->ulOurSequenceNumber - pxTCPWindow->tx.ulFirstSequenceNumber,
pxTCPWindow->rx.ulCurrentSequenceNumber - pxTCPWindow->rx.ulFirstSequenceNumber ) );
}
return xSendLength;
}
/*-----------------------------------------------------------*/
/*
* prvCheckRxData(): called from prvTCPHandleState()
*
* The first thing that will be done is find the TCP payload data
* and check the length of this data.
*/
static BaseType_t prvCheckRxData( NetworkBufferDescriptor_t *pxNetworkBuffer, uint8_t **ppucRecvData )
{
TCPPacket_t *pxTCPPacket = ( TCPPacket_t * ) ( pxNetworkBuffer->pucEthernetBuffer );
TCPHeader_t *pxTCPHeader = &( pxTCPPacket->xTCPHeader );
int32_t lLength, lTCPHeaderLength, lReceiveLength, lUrgentLength;
/* Determine the length and the offset of the user-data sent to this
node.
The size of the TCP header is given in a multiple of 4-byte words (single
byte, needs no ntoh() translation). A shift-right 2: is the same as
(offset >> 4) * 4. */
lTCPHeaderLength = ( BaseType_t ) ( ( pxTCPHeader->ucTCPOffset & VALID_BITS_IN_TCP_OFFSET_BYTE ) >> 2 );
/* Let pucRecvData point to the first byte received. */
*ppucRecvData = pxNetworkBuffer->pucEthernetBuffer + ipSIZE_OF_ETH_HEADER + ipSIZE_OF_IPv4_HEADER + lTCPHeaderLength;
/* Calculate lReceiveLength - the length of the TCP data received. This is
equal to the total packet length minus:
( LinkLayer length (14) + IP header length (20) + size of TCP header(20 +) ).*/
lReceiveLength = ( ( int32_t ) pxNetworkBuffer->xDataLength ) - ( int32_t ) ipSIZE_OF_ETH_HEADER;
lLength = ( int32_t )FreeRTOS_htons( pxTCPPacket->xIPHeader.usLength );
if( lReceiveLength > lLength )
{
/* More bytes were received than the reported length, often because of
padding bytes at the end. */
lReceiveLength = lLength;
}
/* Subtract the size of the TCP and IP headers and the actual data size is
known. */
if( lReceiveLength > ( lTCPHeaderLength + ( int32_t ) ipSIZE_OF_IPv4_HEADER ) )
{
lReceiveLength -= ( lTCPHeaderLength + ( int32_t ) ipSIZE_OF_IPv4_HEADER );
}
else
{
lReceiveLength = 0;
}
/* Urgent Pointer:
This field communicates the current value of the urgent pointer as a
positive offset from the sequence number in this segment. The urgent
pointer points to the sequence number of the octet following the urgent
data. This field is only be interpreted in segments with the URG control
bit set. */
if( ( pxTCPHeader->ucTCPFlags & ipTCP_FLAG_URG ) != 0u )
{
/* Although we ignore the urgent data, we have to skip it. */
lUrgentLength = ( int32_t ) FreeRTOS_htons( pxTCPHeader->usUrgent );
*ppucRecvData += lUrgentLength;
lReceiveLength -= FreeRTOS_min_int32( lReceiveLength, lUrgentLength );
}
return ( BaseType_t ) lReceiveLength;
}
/*-----------------------------------------------------------*/
/*
* prvStoreRxData(): called from prvTCPHandleState()
*
* The second thing is to do is check if the payload data may be accepted
* If so, they will be added to the reception queue.
*/
static BaseType_t prvStoreRxData( FreeRTOS_Socket_t *pxSocket, uint8_t *pucRecvData,
NetworkBufferDescriptor_t *pxNetworkBuffer, uint32_t ulReceiveLength )
{
TCPPacket_t *pxTCPPacket = ( TCPPacket_t * ) ( pxNetworkBuffer->pucEthernetBuffer );
TCPHeader_t *pxTCPHeader = &pxTCPPacket->xTCPHeader;
TCPWindow_t *pxTCPWindow = &pxSocket->u.xTCP.xTCPWindow;
uint32_t ulSequenceNumber, ulSpace;
int32_t lOffset, lStored;
BaseType_t xResult = 0;
ulSequenceNumber = FreeRTOS_ntohl( pxTCPHeader->ulSequenceNumber );
if( ( ulReceiveLength > 0u ) && ( pxSocket->u.xTCP.ucTCPState >= eSYN_RECEIVED ) )
{
/* See if way may accept the data contents and forward it to the socket
owner.
If it can't be "accept"ed it may have to be stored and send a selective
ack (SACK) option to confirm it. In that case, xTCPWindowRxStore() will be
called later to store an out-of-order packet (in case lOffset is
negative). */
if ( pxSocket->u.xTCP.rxStream )
{
ulSpace = ( uint32_t )uxStreamBufferGetSpace ( pxSocket->u.xTCP.rxStream );
}
else
{
ulSpace = ( uint32_t )pxSocket->u.xTCP.uxRxStreamSize;
}
lOffset = lTCPWindowRxCheck( pxTCPWindow, ulSequenceNumber, ulReceiveLength, ulSpace );
if( lOffset >= 0 )
{
/* New data has arrived and may be made available to the user. See
if the head marker in rxStream may be advanced, only if lOffset == 0.
In case the low-water mark is reached, bLowWater will be set
"low-water" here stands for "little space". */
lStored = lTCPAddRxdata( pxSocket, ( uint32_t ) lOffset, pucRecvData, ulReceiveLength );
if( lStored != ( int32_t ) ulReceiveLength )
{
FreeRTOS_debug_printf( ( "lTCPAddRxdata: stored %ld / %lu bytes??\n", lStored, ulReceiveLength ) );
/* Received data could not be stored. The socket's flag
bMallocError has been set. The socket now has the status
eCLOSE_WAIT and a RST packet will be sent back. */
prvTCPSendReset( pxNetworkBuffer );
xResult = -1;
}
}
/* After a missing packet has come in, higher packets may be passed to
the user. */
#if( ipconfigUSE_TCP_WIN == 1 )
{
/* Now lTCPAddRxdata() will move the rxHead pointer forward
so data becomes available to the user immediately
In case the low-water mark is reached, bLowWater will be set. */
if( ( xResult == 0 ) && ( pxTCPWindow->ulUserDataLength > 0 ) )
{
lTCPAddRxdata( pxSocket, 0ul, NULL, pxTCPWindow->ulUserDataLength );
pxTCPWindow->ulUserDataLength = 0;
}
}
#endif /* ipconfigUSE_TCP_WIN */
}
else
{
pxTCPWindow->ucOptionLength = 0u;
}
return xResult;
}
/*-----------------------------------------------------------*/
/* Set the TCP options (if any) for the outgoing packet. */
static UBaseType_t prvSetOptions( FreeRTOS_Socket_t *pxSocket, NetworkBufferDescriptor_t *pxNetworkBuffer )
{
TCPPacket_t *pxTCPPacket = ( TCPPacket_t * ) ( pxNetworkBuffer->pucEthernetBuffer );
TCPHeader_t *pxTCPHeader = &pxTCPPacket->xTCPHeader;
TCPWindow_t *pxTCPWindow = &pxSocket->u.xTCP.xTCPWindow;
UBaseType_t uxOptionsLength = pxTCPWindow->ucOptionLength;
#if( ipconfigUSE_TCP_WIN == 1 )
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[%d,%d]: optlen %lu sending %lu - %lu\n",
pxSocket->usLocalPort,
pxSocket->u.xTCP.usRemotePort,
uxOptionsLength,
FreeRTOS_ntohl( pxTCPWindow->ulOptionsData[ 1 ] ) - pxSocket->u.xTCP.xTCPWindow.rx.ulFirstSequenceNumber,
FreeRTOS_ntohl( pxTCPWindow->ulOptionsData[ 2 ] ) - pxSocket->u.xTCP.xTCPWindow.rx.ulFirstSequenceNumber ) );
memcpy( pxTCPHeader->ucOptdata, pxTCPWindow->ulOptionsData, ( 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.ucTCPState >= 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 %d\n", pxSocket->u.xTCP.usCurMSS ) );
}
pxTCPHeader->ucOptdata[ 0 ] = TCP_OPT_MSS;
pxTCPHeader->ucOptdata[ 1 ] = TCP_OPT_MSS_LEN;
pxTCPHeader->ucOptdata[ 2 ] = ( uint8_t ) ( ( pxSocket->u.xTCP.usCurMSS ) >> 8 );
pxTCPHeader->ucOptdata[ 3 ] = ( uint8_t ) ( ( pxSocket->u.xTCP.usCurMSS ) & 0xffu );
uxOptionsLength = 4u;
pxTCPHeader->ucTCPOffset = ( uint8_t )( ( ipSIZE_OF_TCP_HEADER + uxOptionsLength ) << 2 );
}
return uxOptionsLength;
}
/*-----------------------------------------------------------*/
/*
* prvHandleSynReceived(): called from prvTCPHandleState()
*
* Called from the states: eSYN_RECEIVED and eCONNECT_SYN
* If the flags received are correct, the socket will move to eESTABLISHED.
*/
static BaseType_t prvHandleSynReceived( FreeRTOS_Socket_t *pxSocket, NetworkBufferDescriptor_t **ppxNetworkBuffer,
uint32_t ulReceiveLength, UBaseType_t uxOptionsLength )
{
TCPPacket_t *pxTCPPacket = ( TCPPacket_t * ) ( (*ppxNetworkBuffer)->pucEthernetBuffer );
TCPHeader_t *pxTCPHeader = &pxTCPPacket->xTCPHeader;
TCPWindow_t *pxTCPWindow = &pxSocket->u.xTCP.xTCPWindow;
uint8_t ucTCPFlags = pxTCPHeader->ucTCPFlags;
uint32_t ulSequenceNumber = FreeRTOS_ntohl( pxTCPHeader->ulSequenceNumber );
BaseType_t xSendLength = 0;
/* Either expect a ACK or a SYN+ACK. */
uint16_t usExpect = ( uint16_t ) ipTCP_FLAG_ACK;
if( pxSocket->u.xTCP.ucTCPState == eCONNECT_SYN )
{
usExpect |= ( uint16_t ) ipTCP_FLAG_SYN;
}
if( ( ucTCPFlags & 0x17u ) != usExpect )
{
/* eSYN_RECEIVED: flags 0010 expected, not 0002. */
/* eSYN_RECEIVED: flags ACK expected, not SYN. */
FreeRTOS_debug_printf( ( "%s: flags %04X expected, not %04X\n",
pxSocket->u.xTCP.ucTCPState == eSYN_RECEIVED ? "eSYN_RECEIVED" : "eCONNECT_SYN",
usExpect, ucTCPFlags ) );
vTCPStateChange( pxSocket, eCLOSE_WAIT );
pxTCPHeader->ucTCPFlags |= ipTCP_FLAG_RST;
xSendLength = ( BaseType_t ) ( ipSIZE_OF_IPv4_HEADER + ipSIZE_OF_TCP_HEADER + uxOptionsLength );
pxTCPHeader->ucTCPOffset = ( uint8_t )( ( ipSIZE_OF_TCP_HEADER + uxOptionsLength ) << 2 );
}
else
{
pxTCPWindow->usPeerPortNumber = pxSocket->u.xTCP.usRemotePort;
pxTCPWindow->usOurPortNumber = pxSocket->usLocalPort;
if( pxSocket->u.xTCP.ucTCPState == eCONNECT_SYN )
{
TCPPacket_t *pxLastTCPPacket = ( TCPPacket_t * ) ( pxSocket->u.xTCP.xPacket.u.ucLastPacket );
/* Clear the SYN flag in lastPacket. */
pxLastTCPPacket->xTCPHeader.ucTCPFlags = ipTCP_FLAG_ACK;
/* This socket was the one connecting actively so now perofmr the
synchronisation. */
vTCPWindowInit( &pxSocket->u.xTCP.xTCPWindow,
ulSequenceNumber, pxSocket->u.xTCP.xTCPWindow.ulOurSequenceNumber, ( uint32_t ) pxSocket->u.xTCP.usCurMSS );
pxTCPWindow->rx.ulCurrentSequenceNumber = pxTCPWindow->rx.ulHighestSequenceNumber = ulSequenceNumber + 1u;
pxTCPWindow->tx.ulCurrentSequenceNumber++; /* because we send a TCP_SYN [ | TCP_ACK ]; */
pxTCPWindow->ulNextTxSequenceNumber++;
}
else if( ulReceiveLength == 0u )
{
pxTCPWindow->rx.ulCurrentSequenceNumber = ulSequenceNumber;
}
/* The SYN+ACK has been confirmed, increase the next sequence number by
1. */
pxTCPWindow->ulOurSequenceNumber = pxTCPWindow->tx.ulFirstSequenceNumber + 1u;
#if( ipconfigUSE_TCP_WIN == 1 )
{
FreeRTOS_debug_printf( ( "TCP: %s %d => %lxip:%d set ESTAB (scaling %u)\n",
pxSocket->u.xTCP.ucTCPState == eCONNECT_SYN ? "active" : "passive",
pxSocket->usLocalPort,
pxSocket->u.xTCP.ulRemoteIP,
pxSocket->u.xTCP.usRemotePort,
( unsigned ) pxSocket->u.xTCP.bits.bWinScaling ) );
}
#endif /* ipconfigUSE_TCP_WIN */
if( ( pxSocket->u.xTCP.ucTCPState == eCONNECT_SYN ) || ( ulReceiveLength != 0u ) )
{
pxTCPHeader->ucTCPFlags = ipTCP_FLAG_ACK;
xSendLength = ( BaseType_t ) ( ipSIZE_OF_IPv4_HEADER + ipSIZE_OF_TCP_HEADER + uxOptionsLength );
pxTCPHeader->ucTCPOffset = ( uint8_t ) ( ( ipSIZE_OF_TCP_HEADER + uxOptionsLength ) << 2 );
}
#if( ipconfigUSE_TCP_WIN != 0 )
{
if( pxSocket->u.xTCP.bits.bWinScaling == pdFALSE_UNSIGNED )
{
/* The other party did not send a scaling factor.
A shifting factor in this side must be canceled. */
pxSocket->u.xTCP.ucMyWinScaleFactor = 0;
pxSocket->u.xTCP.ucPeerWinScaleFactor = 0;
}
}
#endif /* ipconfigUSE_TCP_WIN */
/* This was the third step of connecting: SYN, SYN+ACK, ACK so now the
connection is established. */
vTCPStateChange( pxSocket, eESTABLISHED );
}
return xSendLength;
}
/*-----------------------------------------------------------*/
/*
* prvHandleEstablished(): called from prvTCPHandleState()
*
* Called if the status is eESTABLISHED. Data reception has been handled
* earlier. Here the ACK's from peer will be checked, and if a FIN is received,
* the code will check if it may be accepted, i.e. if all expected data has been
* completely received.
*/
static BaseType_t prvHandleEstablished( FreeRTOS_Socket_t *pxSocket, NetworkBufferDescriptor_t **ppxNetworkBuffer,
uint32_t ulReceiveLength, UBaseType_t uxOptionsLength )
{
TCPPacket_t *pxTCPPacket = ( TCPPacket_t * ) ( (*ppxNetworkBuffer)->pucEthernetBuffer );
TCPHeader_t *pxTCPHeader = &pxTCPPacket->xTCPHeader;
TCPWindow_t *pxTCPWindow = &pxSocket->u.xTCP.xTCPWindow;
uint8_t ucTCPFlags = pxTCPHeader->ucTCPFlags;
uint32_t ulSequenceNumber = FreeRTOS_ntohl( pxTCPHeader->ulSequenceNumber ), ulCount;
BaseType_t xSendLength = 0, xMayClose = pdFALSE, bRxComplete, bTxDone;
int32_t lDistance, lSendResult;
/* Remember the window size the peer is advertising. */
pxSocket->u.xTCP.ulWindowSize = FreeRTOS_ntohs( pxTCPHeader->usWindow );
#if( ipconfigUSE_TCP_WIN != 0 )
{
pxSocket->u.xTCP.ulWindowSize =
( pxSocket->u.xTCP.ulWindowSize << pxSocket->u.xTCP.ucPeerWinScaleFactor );
}
#endif
if( ( ucTCPFlags & ( uint8_t ) ipTCP_FLAG_ACK ) != 0u )
{
ulCount = ulTCPWindowTxAck( pxTCPWindow, FreeRTOS_ntohl( pxTCPPacket->xTCPHeader.ulAckNr ) );
/* ulTCPWindowTxAck() returns the number of bytes which have been acked,
starting at 'tx.ulCurrentSequenceNumber'. Advance the tail pointer in
txStream. */
if( ( pxSocket->u.xTCP.txStream != NULL ) && ( ulCount > 0u ) )
{
/* Just advancing the tail index, 'ulCount' bytes have been
confirmed, and because there is new space in the txStream, the
user/owner should be woken up. */
/* _HT_ : only in case the socket's waiting? */
if( uxStreamBufferGet( pxSocket->u.xTCP.txStream, 0u, NULL, ( size_t ) ulCount, pdFALSE ) != 0u )
{
pxSocket->xEventBits |= eSOCKET_SEND;
#if ipconfigSUPPORT_SELECT_FUNCTION == 1
{
if( ( pxSocket->xSelectBits & eSELECT_WRITE ) != 0 )
{
pxSocket->xEventBits |= ( eSELECT_WRITE << SOCKET_EVENT_BIT_COUNT );
}
}
#endif
/* In case the socket owner has installed an OnSent handler,
call it now. */
#if( ipconfigUSE_CALLBACKS == 1 )
{
if( ipconfigIS_VALID_PROG_ADDRESS( pxSocket->u.xTCP.pxHandleSent ) )
{
pxSocket->u.xTCP.pxHandleSent( ( Socket_t )pxSocket, ulCount );
}
}
#endif /* ipconfigUSE_CALLBACKS == 1 */
}
}
}
/* If this socket has a stream for transmission, add the data to the
outgoing segment(s). */
if( pxSocket->u.xTCP.txStream != NULL )
{
prvTCPAddTxData( pxSocket );
}
pxSocket->u.xTCP.xTCPWindow.ulOurSequenceNumber = pxTCPWindow->tx.ulCurrentSequenceNumber;
if( ( pxSocket->u.xTCP.bits.bFinAccepted != pdFALSE_UNSIGNED ) || ( ( ucTCPFlags & ( uint8_t ) ipTCP_FLAG_FIN ) != 0u ) )
{
/* Peer is requesting to stop, see if we're really finished. */
xMayClose = pdTRUE;
/* Checks are only necessary if we haven't sent a FIN yet. */
if( pxSocket->u.xTCP.bits.bFinSent == pdFALSE_UNSIGNED )
{
/* xTCPWindowTxDone returns true when all Tx queues are empty. */
bRxComplete = xTCPWindowRxEmpty( pxTCPWindow );
bTxDone = xTCPWindowTxDone( pxTCPWindow );
if( ( bRxComplete == 0 ) || ( bTxDone == 0 ) )
{
/* Refusing FIN: Rx incomp 1 optlen 4 tx done 1. */
FreeRTOS_debug_printf( ( "Refusing FIN[%u,%u]: RxCompl %lu tx done %ld\n",
pxSocket->usLocalPort,
pxSocket->u.xTCP.usRemotePort,
bRxComplete, bTxDone ) );
xMayClose = pdFALSE;
}
else
{
lDistance = ( int32_t ) ( ulSequenceNumber + ulReceiveLength - pxTCPWindow->rx.ulCurrentSequenceNumber );
if( lDistance > 1 )
{
FreeRTOS_debug_printf( ( "Refusing FIN: Rx not complete %ld (cur %lu high %lu)\n",
lDistance, pxTCPWindow->rx.ulCurrentSequenceNumber - pxTCPWindow->rx.ulFirstSequenceNumber,
pxTCPWindow->rx.ulHighestSequenceNumber - pxTCPWindow->rx.ulFirstSequenceNumber ) );
xMayClose = pdFALSE;
}
}
}
if( xTCPWindowLoggingLevel > 0 )
{
FreeRTOS_debug_printf( ( "TCP: FIN received, mayClose = %ld (Rx %lu Len %ld, Tx %lu)\n",
xMayClose, ulSequenceNumber - pxSocket->u.xTCP.xTCPWindow.rx.ulFirstSequenceNumber, ulReceiveLength,
pxTCPWindow->tx.ulCurrentSequenceNumber - pxSocket->u.xTCP.xTCPWindow.tx.ulFirstSequenceNumber ) );
}
if( xMayClose != pdFALSE )
{
pxSocket->u.xTCP.bits.bFinAccepted = pdTRUE_UNSIGNED;
xSendLength = prvTCPHandleFin( pxSocket, *ppxNetworkBuffer );
}
}
if( xMayClose == pdFALSE )
{
pxTCPHeader->ucTCPFlags = ipTCP_FLAG_ACK;
if( ulReceiveLength != 0u )
{
xSendLength = ( BaseType_t ) ( ipSIZE_OF_IPv4_HEADER + ipSIZE_OF_TCP_HEADER + uxOptionsLength );
/* TCP-offsett equals '( ( length / 4 ) << 4 )', resulting in a shift-left 2 */
pxTCPHeader->ucTCPOffset = ( uint8_t )( ( ipSIZE_OF_TCP_HEADER + uxOptionsLength ) << 2 );
if( pxSocket->u.xTCP.bits.bFinSent != pdFALSE_UNSIGNED )
{
pxTCPWindow->tx.ulCurrentSequenceNumber = pxTCPWindow->tx.ulFINSequenceNumber;
}
}
/* Now get data to be transmitted. */
/* _HT_ patch: since the MTU has be fixed at 1500 in stead of 1526, TCP
can not send-out both TCP options and also a full packet. Sending
options (SACK) is always more urgent than sending data, which can be
sent later. */
if( uxOptionsLength == 0u )
{
/* prvTCPPrepareSend might allocate a bigger network buffer, if
necessary. */
lSendResult = prvTCPPrepareSend( pxSocket, ppxNetworkBuffer, uxOptionsLength );
if( lSendResult > 0 )
{
xSendLength = ( BaseType_t ) lSendResult;
}
}
}
return xSendLength;
}
/*-----------------------------------------------------------*/