/** @file
Routines to process TCP option.
Copyright (c) 2009 - 2010, Intel Corporation. All rights reserved.<BR>
This program and the accompanying materials
are licensed and made available under the terms and conditions of the BSD License
which accompanies this distribution. The full text of the license may be found at
http://opensource.org/licenses/bsd-license.php.
THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
**/
#include "TcpMain.h"
/**
Get a UINT16 value from buffer.
@param[in] Buf Pointer to input buffer.
@return The UINT16 value obtained from the buffer.
**/
UINT16
TcpGetUint16 (
IN UINT8 *Buf
)
{
UINT16 Value;
CopyMem (&Value, Buf, sizeof (UINT16));
return NTOHS (Value);
}
/**
Get a UINT32 value from buffer.
@param[in] Buf Pointer to input buffer.
@return The UINT32 value obtained from the buffer.
**/
UINT32
TcpGetUint32 (
IN UINT8 *Buf
)
{
UINT32 Value;
CopyMem (&Value, Buf, sizeof (UINT32));
return NTOHL (Value);
}
/**
Put a UINT32 value in buffer.
@param[out] Buf Pointer to the buffer.
@param[in] Data The UINT32 Date to put in the buffer.
**/
VOID
TcpPutUint32 (
OUT UINT8 *Buf,
IN UINT32 Data
)
{
Data = HTONL (Data);
CopyMem (Buf, &Data, sizeof (UINT32));
}
/**
Compute the window scale value according to the given buffer size.
@param[in] Tcb Pointer to the TCP_CB of this TCP instance.
@return The scale value.
**/
UINT8
TcpComputeScale (
IN TCP_CB *Tcb
)
{
UINT8 Scale;
UINT32 BufSize;
ASSERT ((Tcb != NULL) && (Tcb->Sk != NULL));
BufSize = GET_RCV_BUFFSIZE (Tcb->Sk);
Scale = 0;
while ((Scale < TCP_OPTION_MAX_WS) && ((UINT32) (TCP_OPTION_MAX_WIN << Scale) < BufSize)) {
Scale++;
}
return Scale;
}
/**
Build the TCP option in three-way handshake.
@param[in] Tcb Pointer to the TCP_CB of this TCP instance.
@param[in] Nbuf Pointer to the buffer to store the options.
@return The total length of the TCP option field.
**/
UINT16
TcpSynBuildOption (
IN TCP_CB *Tcb,
IN NET_BUF *Nbuf
)
{
UINT8 *Data;
UINT16 Len;
ASSERT ((Tcb != NULL) && (Nbuf != NULL) && (Nbuf->Tcp == NULL));
Len = 0;
//
// Add a timestamp option if not disabled by the application
// and it is the first SYN segment, or the peer has sent
// us its timestamp.
//
if (!TCP_FLG_ON (Tcb->CtrlFlag, TCP_CTRL_NO_TS) &&
(!TCP_FLG_ON (TCPSEG_NETBUF (Nbuf)->Flag, TCP_FLG_ACK) ||
TCP_FLG_ON (Tcb->CtrlFlag, TCP_CTRL_RCVD_TS))
) {
Data = NetbufAllocSpace (
Nbuf,
TCP_OPTION_TS_ALIGNED_LEN,
NET_BUF_HEAD
);
ASSERT (Data != NULL);
Len += TCP_OPTION_TS_ALIGNED_LEN;
TcpPutUint32 (Data, TCP_OPTION_TS_FAST);
TcpPutUint32 (Data + 4, mTcpTick);
TcpPutUint32 (Data + 8, 0);
}
//
// Build window scale option, only when configured
// to send WS option, and either we are doing active
// open or we have received WS option from peer.
//
if (!TCP_FLG_ON (Tcb->CtrlFlag, TCP_CTRL_NO_WS) &&
(!TCP_FLG_ON (TCPSEG_NETBUF (Nbuf)->Flag, TCP_FLG_ACK) ||
TCP_FLG_ON (Tcb->CtrlFlag, TCP_CTRL_RCVD_WS))
) {
Data = NetbufAllocSpace (
Nbuf,
TCP_OPTION_WS_ALIGNED_LEN,
NET_BUF_HEAD
);
ASSERT (Data != NULL);
Len += TCP_OPTION_WS_ALIGNED_LEN;
TcpPutUint32 (Data, TCP_OPTION_WS_FAST | TcpComputeScale (Tcb));
}
//
// Build the MSS option.
//
Data = NetbufAllocSpace (Nbuf, TCP_OPTION_MSS_LEN, 1);
ASSERT (Data != NULL);
Len += TCP_OPTION_MSS_LEN;
TcpPutUint32 (Data, TCP_OPTION_MSS_FAST | Tcb->RcvMss);
return Len;
}
/**
Build the TCP option in synchronized states.
@param[in] Tcb Pointer to the TCP_CB of this TCP instance.
@param[in] Nbuf Pointer to the buffer to store the options.
@return The total length of the TCP option field.
**/
UINT16
TcpBuildOption (
IN TCP_CB *Tcb,
IN NET_BUF *Nbuf
)
{
UINT8 *Data;
UINT16 Len;
ASSERT ((Tcb != NULL) && (Nbuf != NULL) && (Nbuf->Tcp == NULL));
Len = 0;
//
// Build the Timestamp option.
//
if (TCP_FLG_ON (Tcb->CtrlFlag, TCP_CTRL_SND_TS) &&
!TCP_FLG_ON (TCPSEG_NETBUF (Nbuf)->Flag, TCP_FLG_RST)
) {
Data = NetbufAllocSpace (
Nbuf,
TCP_OPTION_TS_ALIGNED_LEN,
NET_BUF_HEAD
);
ASSERT (Data != NULL);
Len += TCP_OPTION_TS_ALIGNED_LEN;
TcpPutUint32 (Data, TCP_OPTION_TS_FAST);
TcpPutUint32 (Data + 4, mTcpTick);
TcpPutUint32 (Data + 8, Tcb->TsRecent);
}
return Len;
}
/**
Parse the supported options.
@param[in] Tcp Pointer to the TCP_CB of this TCP instance.
@param[in, out] Option Pointer to the TCP_OPTION used to store the
successfully pasrsed options.
@retval 0 The options are successfully pasrsed.
@retval -1 Ilegal option was found.
**/
INTN
TcpParseOption (
IN TCP_HEAD *Tcp,
IN OUT TCP_OPTION *Option
)
{
UINT8 *Head;
UINT8 TotalLen;
UINT8 Cur;
UINT8 Type;
UINT8 Len;
ASSERT ((Tcp != NULL) && (Option != NULL));
Option->Flag = 0;
TotalLen = (UINT8) ((Tcp->HeadLen << 2) - sizeof (TCP_HEAD));
if (TotalLen <= 0) {
return 0;
}
Head = (UINT8 *) (Tcp + 1);
//
// Fast process of the timestamp option.
//
if ((TotalLen == TCP_OPTION_TS_ALIGNED_LEN) && (TcpGetUint32 (Head) == TCP_OPTION_TS_FAST)) {
Option->TSVal = TcpGetUint32 (Head + 4);
Option->TSEcr = TcpGetUint32 (Head + 8);
Option->Flag = TCP_OPTION_RCVD_TS;
return 0;
}
//
// Slow path to process the options.
//
Cur = 0;
while (Cur < TotalLen) {
Type = Head[Cur];
switch (Type) {
case TCP_OPTION_MSS:
Len = Head[Cur + 1];
if ((Len != TCP_OPTION_MSS_LEN) || (TotalLen - Cur < TCP_OPTION_MSS_LEN)) {
return -1;
}
Option->Mss = TcpGetUint16 (&Head[Cur + 2]);
TCP_SET_FLG (Option->Flag, TCP_OPTION_RCVD_MSS);
Cur += TCP_OPTION_MSS_LEN;
break;
case TCP_OPTION_WS:
Len = Head[Cur + 1];
if ((Len != TCP_OPTION_WS_LEN) || (TotalLen - Cur < TCP_OPTION_WS_LEN)) {
return -1;
}
Option->WndScale = (UINT8) MIN (14, Head[Cur + 2]);
TCP_SET_FLG (Option->Flag, TCP_OPTION_RCVD_WS);
Cur += TCP_OPTION_WS_LEN;
break;
case TCP_OPTION_TS:
Len = Head[Cur + 1];
if ((Len != TCP_OPTION_TS_LEN) || (TotalLen - Cur < TCP_OPTION_TS_LEN)) {
return -1;
}
Option->TSVal = TcpGetUint32 (&Head[Cur + 2]);
Option->TSEcr = TcpGetUint32 (&Head[Cur + 6]);
TCP_SET_FLG (Option->Flag, TCP_OPTION_RCVD_TS);
Cur += TCP_OPTION_TS_LEN;
break;
case TCP_OPTION_NOP:
Cur++;
break;
case TCP_OPTION_EOP:
Cur = TotalLen;
break;
default:
Len = Head[Cur + 1];
if ((TotalLen - Cur) < Len || Len < 2) {
return -1;
}
Cur = (UINT8) (Cur + Len);
break;
}
}
return 0;
}
/**
Check the segment against PAWS.
@param[in] Tcb Pointer to the TCP_CB of this TCP instance.
@param[in] TSVal The timestamp value.
@retval 1 The segment passed the PAWS check.
@retval 0 The segment failed to pass the PAWS check.
**/
UINT32
TcpPawsOK (
IN TCP_CB *Tcb,
IN UINT32 TSVal
)
{
//
// PAWS as defined in RFC1323, buggy...
//
if (TCP_TIME_LT (TSVal, Tcb->TsRecent) &&
TCP_TIME_LT (Tcb->TsRecentAge + TCP_PAWS_24DAY, mTcpTick)
) {
return 0;
}
return 1;
}