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CloverBootloader/NetworkPkg/TcpDxe/TcpOutput.c

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/** @file
TCP output process routines.
Copyright (c) 2009 - 2018, Intel Corporation. All rights reserved.<BR>
SPDX-License-Identifier: BSD-2-Clause-Patent
**/
#include "TcpMain.h"
UINT8 mTcpOutFlag[] = {
0, // TCP_CLOSED
0, // TCP_LISTEN
TCP_FLG_SYN, // TCP_SYN_SENT
TCP_FLG_SYN | TCP_FLG_ACK, // TCP_SYN_RCVD
TCP_FLG_ACK, // TCP_ESTABLISHED
TCP_FLG_FIN | TCP_FLG_ACK, // TCP_FIN_WAIT_1
TCP_FLG_ACK, // TCP_FIN_WAIT_2
TCP_FLG_ACK | TCP_FLG_FIN, // TCP_CLOSING
TCP_FLG_ACK, // TCP_TIME_WAIT
TCP_FLG_ACK, // TCP_CLOSE_WAIT
TCP_FLG_FIN | TCP_FLG_ACK // TCP_LAST_ACK
};
/**
Compute the sequence space left in the old receive window.
@param[in] Tcb Pointer to the TCP_CB of this TCP instance.
@return The sequence space left in the old receive window.
**/
UINT32
TcpRcvWinOld (
IN TCP_CB *Tcb
)
{
UINT32 OldWin;
OldWin = 0;
if (TCP_SEQ_GT (Tcb->RcvWl2 + Tcb->RcvWnd, Tcb->RcvNxt)) {
OldWin = TCP_SUB_SEQ (
Tcb->RcvWl2 + Tcb->RcvWnd,
Tcb->RcvNxt
);
}
return OldWin;
}
/**
Compute the current receive window.
@param[in] Tcb Pointer to the TCP_CB of this TCP instance.
@return The size of the current receive window, in bytes.
**/
UINT32
TcpRcvWinNow (
IN TCP_CB *Tcb
)
{
SOCKET *Sk;
UINT32 Win;
UINT32 Increase;
UINT32 OldWin;
Sk = Tcb->Sk;
ASSERT (Sk != NULL);
OldWin = TcpRcvWinOld (Tcb);
Win = SockGetFreeSpace (Sk, SOCK_RCV_BUF);
Increase = 0;
if (Win > OldWin) {
Increase = Win - OldWin;
}
//
// Receiver's SWS: don't advertise a bigger window
// unless it can be increased by at least one Mss or
// half of the receive buffer.
//
if ((Increase > Tcb->SndMss) || (2 * Increase >= GET_RCV_BUFFSIZE (Sk))) {
return Win;
}
return OldWin;
}
/**
Compute the value to fill in the window size field of the outgoing segment.
@param[in, out] Tcb Pointer to the TCP_CB of this TCP instance.
@param[in] Syn The flag to indicate whether the outgoing segment
is a SYN segment.
@return The value of the local receive window size used to fill the outgoing segment.
**/
UINT16
TcpComputeWnd (
IN OUT TCP_CB *Tcb,
IN BOOLEAN Syn
)
{
UINT32 Wnd;
//
// RFC requires that initial window not be scaled
//
if (Syn) {
Wnd = GET_RCV_BUFFSIZE (Tcb->Sk);
} else {
Wnd = TcpRcvWinNow (Tcb);
Tcb->RcvWnd = Wnd;
}
Wnd = MIN (Wnd >> Tcb->RcvWndScale, 0xffff);
return NTOHS ((UINT16)Wnd);
}
/**
Get the maximum SndNxt.
@param[in] Tcb Pointer to the TCP_CB of this TCP instance.
@return The sequence number of the maximum SndNxt.
**/
TCP_SEQNO
TcpGetMaxSndNxt (
IN TCP_CB *Tcb
)
{
LIST_ENTRY *Entry;
NET_BUF *Nbuf;
if (IsListEmpty (&Tcb->SndQue)) {
return Tcb->SndNxt;
}
Entry = Tcb->SndQue.BackLink;
Nbuf = NET_LIST_USER_STRUCT (Entry, NET_BUF, List);
ASSERT (TCP_SEQ_GEQ (TCPSEG_NETBUF (Nbuf)->End, Tcb->SndNxt));
return TCPSEG_NETBUF (Nbuf)->End;
}
/**
Compute how much data to send.
@param[in] Tcb Pointer to the TCP_CB of this TCP instance.
@param[in] Force If TRUE, to ignore the sender's SWS avoidance algorithm and send
out data by force.
@return The length of the data can be sent. If 0, no data can be sent.
**/
UINT32
TcpDataToSend (
IN TCP_CB *Tcb,
IN INTN Force
)
{
SOCKET *Sk;
UINT32 Win;
UINT32 Len;
UINT32 Left;
UINT32 Limit;
Sk = Tcb->Sk;
ASSERT (Sk != NULL);
//
// TCP should NOT send data beyond the send window
// and congestion window. The right edge of send
// window is defined as SND.WL2 + SND.WND. The right
// edge of congestion window is defined as SND.UNA +
// CWND.
//
Win = 0;
Limit = Tcb->SndWl2 + Tcb->SndWnd;
if (TCP_SEQ_GT (Limit, Tcb->SndUna + Tcb->CWnd)) {
Limit = Tcb->SndUna + Tcb->CWnd;
}
if (TCP_SEQ_GT (Limit, Tcb->SndNxt)) {
Win = TCP_SUB_SEQ (Limit, Tcb->SndNxt);
}
//
// The data to send contains two parts: the data on the
// socket send queue, and the data on the TCB's send
// buffer. The later can be non-zero if the peer shrinks
// its advertised window.
//
Left = GET_SND_DATASIZE (Sk) + TCP_SUB_SEQ (TcpGetMaxSndNxt (Tcb), Tcb->SndNxt);
Len = MIN (Win, Left);
if (Len > Tcb->SndMss) {
Len = Tcb->SndMss;
}
if ((Force != 0) || ((Len == 0) && (Left == 0))) {
return Len;
}
if ((Len == 0) && (Left != 0)) {
goto SetPersistTimer;
}
//
// Sender's SWS avoidance: Don't send a small segment unless
// a)A full-sized segment can be sent,
// b)At least one-half of the maximum sized windows that
// the other end has ever advertised.
// c)It can send everything it has, and either it isn't
// expecting an ACK, or the Nagle algorithm is disabled.
//
if ((Len == Tcb->SndMss) || (2 * Len >= Tcb->SndWndMax)) {
return Len;
}
if ((Len == Left) &&
((Tcb->SndNxt == Tcb->SndUna) || TCP_FLG_ON (Tcb->CtrlFlag, TCP_CTRL_NO_NAGLE))
)
{
return Len;
}
//
// RFC1122 suggests to set a timer when SWSA forbids TCP
// sending more data, and combines it with a probe timer.
//
SetPersistTimer:
if (!TCP_TIMER_ON (Tcb->EnabledTimer, TCP_TIMER_REXMIT)) {
DEBUG (
(DEBUG_WARN,
"TcpDataToSend: enter persistent state for TCB %p\n",
Tcb)
);
if (!Tcb->ProbeTimerOn) {
TcpSetProbeTimer (Tcb);
}
}
return 0;
}
/**
Build the TCP header of the TCP segment and transmit the segment by IP.
@param[in, out] Tcb Pointer to the TCP_CB of this TCP instance.
@param[in] Nbuf Pointer to the buffer containing the segment to be
sent out.
@retval 0 The segment was sent out successfully.
@retval -1 An error condition occurred.
**/
INTN
TcpTransmitSegment (
IN OUT TCP_CB *Tcb,
IN NET_BUF *Nbuf
)
{
UINT16 Len;
TCP_HEAD *Head;
TCP_SEG *Seg;
BOOLEAN Syn;
UINT32 DataLen;
ASSERT ((Nbuf != NULL) && (Nbuf->Tcp == NULL));
if (TcpVerifySegment (Nbuf) == 0) {
return -1;
}
DataLen = Nbuf->TotalSize;
Seg = TCPSEG_NETBUF (Nbuf);
Syn = TCP_FLG_ON (Seg->Flag, TCP_FLG_SYN);
if (Syn) {
Len = TcpSynBuildOption (Tcb, Nbuf);
} else {
Len = TcpBuildOption (Tcb, Nbuf);
}
ASSERT ((Len % 4 == 0) && (Len <= 40));
Len += sizeof (TCP_HEAD);
Head = (TCP_HEAD *)NetbufAllocSpace (
Nbuf,
sizeof (TCP_HEAD),
NET_BUF_HEAD
);
ASSERT (Head != NULL);
Nbuf->Tcp = Head;
Head->SrcPort = Tcb->LocalEnd.Port;
Head->DstPort = Tcb->RemoteEnd.Port;
Head->Seq = NTOHL (Seg->Seq);
Head->Ack = NTOHL (Tcb->RcvNxt);
Head->HeadLen = (UINT8)(Len >> 2);
Head->Res = 0;
Head->Wnd = TcpComputeWnd (Tcb, Syn);
Head->Checksum = 0;
//
// Check whether to set the PSH flag.
//
TCP_CLEAR_FLG (Seg->Flag, TCP_FLG_PSH);
if (DataLen != 0) {
if (TCP_FLG_ON (Tcb->CtrlFlag, TCP_CTRL_SND_PSH) &&
TCP_SEQ_BETWEEN (Seg->Seq, Tcb->SndPsh, Seg->End)
)
{
TCP_SET_FLG (Seg->Flag, TCP_FLG_PSH);
TCP_CLEAR_FLG (Tcb->CtrlFlag, TCP_CTRL_SND_PSH);
} else if ((Seg->End == Tcb->SndNxt) && (GET_SND_DATASIZE (Tcb->Sk) == 0)) {
TCP_SET_FLG (Seg->Flag, TCP_FLG_PSH);
}
}
//
// Check whether to set the URG flag and the urgent pointer.
//
TCP_CLEAR_FLG (Seg->Flag, TCP_FLG_URG);
if (TCP_FLG_ON (Tcb->CtrlFlag, TCP_CTRL_SND_URG) && TCP_SEQ_LEQ (Seg->Seq, Tcb->SndUp)) {
TCP_SET_FLG (Seg->Flag, TCP_FLG_URG);
if (TCP_SEQ_LT (Tcb->SndUp, Seg->End)) {
Seg->Urg = (UINT16)TCP_SUB_SEQ (Tcb->SndUp, Seg->Seq);
} else {
Seg->Urg = (UINT16)MIN (
TCP_SUB_SEQ (
Tcb->SndUp,
Seg->Seq
),
0xffff
);
}
}
Head->Flag = Seg->Flag;
Head->Urg = NTOHS (Seg->Urg);
Head->Checksum = TcpChecksum (Nbuf, Tcb->HeadSum);
//
// Update the TCP session's control information.
//
Tcb->RcvWl2 = Tcb->RcvNxt;
if (Syn) {
Tcb->RcvWnd = NTOHS (Head->Wnd);
}
//
// Clear the delayedack flag.
//
Tcb->DelayedAck = 0;
return TcpSendIpPacket (Tcb, Nbuf, &Tcb->LocalEnd.Ip, &Tcb->RemoteEnd.Ip, Tcb->Sk->IpVersion);
}
/**
Get a segment from the Tcb's SndQue.
@param[in] Tcb Pointer to the TCP_CB of this TCP instance.
@param[in] Seq The sequence number of the segment.
@param[in] Len The maximum length of the segment.
@return Pointer to the segment. If NULL, some error occurred.
**/
NET_BUF *
TcpGetSegmentSndQue (
IN TCP_CB *Tcb,
IN TCP_SEQNO Seq,
IN UINT32 Len
)
{
LIST_ENTRY *Head;
LIST_ENTRY *Cur;
NET_BUF *Node;
TCP_SEG *Seg;
NET_BUF *Nbuf;
TCP_SEQNO End;
UINT8 *Data;
UINT8 Flag;
INT32 Offset;
INT32 CopyLen;
ASSERT ((Tcb != NULL) && TCP_SEQ_LEQ (Seq, Tcb->SndNxt) && (Len > 0));
//
// Find the segment that contains the Seq.
//
Head = &Tcb->SndQue;
Node = NULL;
Seg = NULL;
NET_LIST_FOR_EACH (Cur, Head) {
Node = NET_LIST_USER_STRUCT (Cur, NET_BUF, List);
Seg = TCPSEG_NETBUF (Node);
if (TCP_SEQ_LT (Seq, Seg->End) && TCP_SEQ_LEQ (Seg->Seq, Seq)) {
break;
}
}
if ((Cur == Head) || (Seg == NULL) || (Node == NULL)) {
return NULL;
}
//
// Return the buffer if it can be returned without
// adjustment:
//
if ((Seg->Seq == Seq) &&
TCP_SEQ_LEQ (Seg->End, Seg->Seq + Len) &&
!NET_BUF_SHARED (Node)
)
{
NET_GET_REF (Node);
return Node;
}
//
// Create a new buffer and copy data there.
//
Nbuf = NetbufAlloc (Len + TCP_MAX_HEAD);
if (Nbuf == NULL) {
return NULL;
}
NetbufReserve (Nbuf, TCP_MAX_HEAD);
Flag = Seg->Flag;
End = Seg->End;
if (TCP_SEQ_LT (Seq + Len, Seg->End)) {
End = Seq + Len;
}
CopyLen = TCP_SUB_SEQ (End, Seq);
Offset = TCP_SUB_SEQ (Seq, Seg->Seq);
//
// If SYN is set and out of the range, clear the flag.
// Because the sequence of the first byte is SEG.SEQ+1,
// adjust Offset by -1. If SYN is in the range, copy
// one byte less.
//
if (TCP_FLG_ON (Seg->Flag, TCP_FLG_SYN)) {
if (TCP_SEQ_LT (Seg->Seq, Seq)) {
TCP_CLEAR_FLG (Flag, TCP_FLG_SYN);
Offset--;
} else {
CopyLen--;
}
}
//
// If FIN is set and in the range, copy one byte less,
// and if it is out of the range, clear the flag.
//
if (TCP_FLG_ON (Seg->Flag, TCP_FLG_FIN)) {
if (Seg->End == End) {
CopyLen--;
} else {
TCP_CLEAR_FLG (Flag, TCP_FLG_FIN);
}
}
ASSERT (CopyLen >= 0);
//
// Copy data to the segment
//
if (CopyLen != 0) {
Data = NetbufAllocSpace (Nbuf, CopyLen, NET_BUF_TAIL);
ASSERT (Data != NULL);
if ((INT32)NetbufCopy (Node, Offset, CopyLen, Data) != CopyLen) {
goto OnError;
}
}
CopyMem (TCPSEG_NETBUF (Nbuf), Seg, sizeof (TCP_SEG));
TCPSEG_NETBUF (Nbuf)->Seq = Seq;
TCPSEG_NETBUF (Nbuf)->End = End;
TCPSEG_NETBUF (Nbuf)->Flag = Flag;
return Nbuf;
OnError:
NetbufFree (Nbuf);
return NULL;
}
/**
Get a segment from the Tcb's socket buffer.
@param[in] Tcb Pointer to the TCP_CB of this TCP instance.
@param[in] Seq The sequence number of the segment.
@param[in] Len The maximum length of the segment.
@return Pointer to the segment. If NULL, some error occurred.
**/
NET_BUF *
TcpGetSegmentSock (
IN TCP_CB *Tcb,
IN TCP_SEQNO Seq,
IN UINT32 Len
)
{
NET_BUF *Nbuf;
UINT8 *Data;
UINT32 DataGet;
ASSERT ((Tcb != NULL) && (Tcb->Sk != NULL));
Nbuf = NetbufAlloc (Len + TCP_MAX_HEAD);
if (Nbuf == NULL) {
DEBUG (
(DEBUG_ERROR,
"TcpGetSegmentSock: failed to allocate a netbuf for TCB %p\n",
Tcb)
);
return NULL;
}
NetbufReserve (Nbuf, TCP_MAX_HEAD);
DataGet = 0;
if (Len != 0) {
//
// copy data to the segment.
//
Data = NetbufAllocSpace (Nbuf, Len, NET_BUF_TAIL);
ASSERT (Data != NULL);
DataGet = SockGetDataToSend (Tcb->Sk, 0, Len, Data);
}
NET_GET_REF (Nbuf);
TCPSEG_NETBUF (Nbuf)->Seq = Seq;
TCPSEG_NETBUF (Nbuf)->End = Seq + Len;
InsertTailList (&(Tcb->SndQue), &(Nbuf->List));
if (DataGet != 0) {
SockDataSent (Tcb->Sk, DataGet);
}
return Nbuf;
}
/**
Get a segment starting from sequence Seq of a maximum
length of Len.
@param[in] Tcb Pointer to the TCP_CB of this TCP instance.
@param[in] Seq The sequence number of the segment.
@param[in] Len The maximum length of the segment.
@return Pointer to the segment. If NULL, some error occurred.
**/
NET_BUF *
TcpGetSegment (
IN TCP_CB *Tcb,
IN TCP_SEQNO Seq,
IN UINT32 Len
)
{
NET_BUF *Nbuf;
ASSERT (Tcb != NULL);
//
// Compare the SndNxt with the max sequence number sent.
//
if ((Len != 0) && TCP_SEQ_LT (Seq, TcpGetMaxSndNxt (Tcb))) {
Nbuf = TcpGetSegmentSndQue (Tcb, Seq, Len);
} else {
Nbuf = TcpGetSegmentSock (Tcb, Seq, Len);
}
if (TcpVerifySegment (Nbuf) == 0) {
NetbufFree (Nbuf);
return NULL;
}
return Nbuf;
}
/**
Retransmit the segment from sequence Seq.
@param[in] Tcb Pointer to the TCP_CB of this TCP instance.
@param[in] Seq The sequence number of the segment to be retransmitted.
@retval 0 Retransmission succeeded.
@retval -1 Error condition occurred.
**/
INTN
TcpRetransmit (
IN TCP_CB *Tcb,
IN TCP_SEQNO Seq
)
{
NET_BUF *Nbuf;
UINT32 Len;
//
// Compute the maximum length of retransmission. It is
// limited by three factors:
// 1. Less than SndMss
// 2. Must in the current send window
// 3. Will not change the boundaries of queued segments.
//
//
// Handle the Window Retraction if TCP window scale is enabled according to RFC7323:
// On first retransmission, or if the sequence number is out of
// window by less than 2^Rcv.Wind.Shift, then do normal
// retransmission(s) without regard to the receiver window as long
// as the original segment was in window when it was sent.
//
if ((Tcb->SndWndScale != 0) &&
(TCP_SEQ_GT (Seq, Tcb->RetxmitSeqMax) || TCP_SEQ_BETWEEN (Tcb->SndWl2 + Tcb->SndWnd, Seq, Tcb->SndWl2 + Tcb->SndWnd + (1 << Tcb->SndWndScale))))
{
Len = TCP_SUB_SEQ (Tcb->SndNxt, Seq);
DEBUG (
(DEBUG_WARN,
"TcpRetransmit: retransmission without regard to the receiver window for TCB %p\n",
Tcb)
);
} else if (TCP_SEQ_GEQ (Tcb->SndWl2 + Tcb->SndWnd, Seq)) {
Len = TCP_SUB_SEQ (Tcb->SndWl2 + Tcb->SndWnd, Seq);
} else {
DEBUG (
(DEBUG_WARN,
"TcpRetransmit: retransmission cancelled because send window too small for TCB %p\n",
Tcb)
);
return 0;
}
Len = MIN (Len, Tcb->SndMss);
Nbuf = TcpGetSegmentSndQue (Tcb, Seq, Len);
if (Nbuf == NULL) {
return -1;
}
if (TcpVerifySegment (Nbuf) == 0) {
goto OnError;
}
if (TcpTransmitSegment (Tcb, Nbuf) != 0) {
goto OnError;
}
if (TCP_SEQ_GT (Seq, Tcb->RetxmitSeqMax)) {
Tcb->RetxmitSeqMax = Seq;
}
//
// The retransmitted buffer may be on the SndQue,
// trim TCP head because all the buffers on SndQue
// are headless.
//
ASSERT (Nbuf->Tcp != NULL);
NetbufTrim (Nbuf, (Nbuf->Tcp->HeadLen << 2), NET_BUF_HEAD);
Nbuf->Tcp = NULL;
NetbufFree (Nbuf);
return 0;
OnError:
if (Nbuf != NULL) {
NetbufFree (Nbuf);
}
return -1;
}
/**
Verify that all the segments in SndQue are in good shape.
@param[in] Head Pointer to the head node of the SndQue.
@retval 0 At least one segment is broken.
@retval 1 All segments in the specific queue are in good shape.
**/
INTN
TcpCheckSndQue (
IN LIST_ENTRY *Head
)
{
LIST_ENTRY *Entry;
NET_BUF *Nbuf;
TCP_SEQNO Seq;
if (IsListEmpty (Head)) {
return 1;
}
//
// Initialize the Seq.
//
Entry = Head->ForwardLink;
Nbuf = NET_LIST_USER_STRUCT (Entry, NET_BUF, List);
Seq = TCPSEG_NETBUF (Nbuf)->Seq;
NET_LIST_FOR_EACH (Entry, Head) {
Nbuf = NET_LIST_USER_STRUCT (Entry, NET_BUF, List);
if (TcpVerifySegment (Nbuf) == 0) {
return 0;
}
//
// All the node in the SndQue should has:
// SEG.SEQ = LAST_SEG.END
//
if (Seq != TCPSEG_NETBUF (Nbuf)->Seq) {
return 0;
}
Seq = TCPSEG_NETBUF (Nbuf)->End;
}
return 1;
}
/**
Check whether to send data/SYN/FIN and piggyback an ACK.
@param[in, out] Tcb Pointer to the TCP_CB of this TCP instance.
@param[in] Force If TRUE, ignore the sender's SWS avoidance algorithm
and send out data by force.
@return The number of bytes sent.
**/
INTN
TcpToSendData (
IN OUT TCP_CB *Tcb,
IN INTN Force
)
{
UINT32 Len;
INTN Sent;
UINT8 Flag;
NET_BUF *Nbuf;
TCP_SEG *Seg;
TCP_SEQNO Seq;
TCP_SEQNO End;
ASSERT ((Tcb != NULL) && (Tcb->Sk != NULL) && (Tcb->State != TCP_LISTEN));
Sent = 0;
if ((Tcb->State == TCP_CLOSED) || TCP_FLG_ON (Tcb->CtrlFlag, TCP_CTRL_FIN_SENT)) {
return 0;
}
do {
//
// Compute how much data can be sent
//
Len = TcpDataToSend (Tcb, Force);
Seq = Tcb->SndNxt;
ASSERT ((Tcb->State) < (ARRAY_SIZE (mTcpOutFlag)));
Flag = mTcpOutFlag[Tcb->State];
if ((Flag & TCP_FLG_SYN) != 0) {
Seq = Tcb->Iss;
Len = 0;
}
//
// Only send a segment without data if SYN or
// FIN is set.
//
if ((Len == 0) && ((Flag & (TCP_FLG_SYN | TCP_FLG_FIN)) == 0)) {
return Sent;
}
Nbuf = TcpGetSegment (Tcb, Seq, Len);
if (Nbuf == NULL) {
DEBUG (
(DEBUG_ERROR,
"TcpToSendData: failed to get a segment for TCB %p\n",
Tcb)
);
goto OnError;
}
Seg = TCPSEG_NETBUF (Nbuf);
//
// Set the TcpSeg in Nbuf.
//
Len = Nbuf->TotalSize;
End = Seq + Len;
if (TCP_FLG_ON (Flag, TCP_FLG_SYN)) {
End++;
}
if ((Flag & TCP_FLG_FIN) != 0) {
//
// Send FIN if all data is sent, and FIN is
// in the window
//
if ((TcpGetMaxSndNxt (Tcb) == Tcb->SndNxt) &&
(GET_SND_DATASIZE (Tcb->Sk) == 0) &&
TCP_SEQ_LT (End + 1, Tcb->SndWnd + Tcb->SndWl2)
)
{
DEBUG (
(DEBUG_NET,
"TcpToSendData: send FIN to peer for TCB %p in state %s\n",
Tcb,
mTcpStateName[Tcb->State])
);
End++;
} else {
TCP_CLEAR_FLG (Flag, TCP_FLG_FIN);
}
}
Seg->Seq = Seq;
Seg->End = End;
Seg->Flag = Flag;
if ((TcpVerifySegment (Nbuf) == 0) || (TcpCheckSndQue (&Tcb->SndQue) == 0)) {
DEBUG (
(DEBUG_ERROR,
"TcpToSendData: discard a broken segment for TCB %p\n",
Tcb)
);
goto OnError;
}
//
// Don't send an empty segment here.
//
if (Seg->End == Seg->Seq) {
DEBUG (
(DEBUG_WARN,
"TcpToSendData: created a empty segment for TCB %p, free it now\n",
Tcb)
);
goto OnError;
}
if (TcpTransmitSegment (Tcb, Nbuf) != 0) {
NetbufTrim (Nbuf, (Nbuf->Tcp->HeadLen << 2), NET_BUF_HEAD);
Nbuf->Tcp = NULL;
if ((Flag & TCP_FLG_FIN) != 0) {
TCP_SET_FLG (Tcb->CtrlFlag, TCP_CTRL_FIN_SENT);
}
goto OnError;
}
Sent += TCP_SUB_SEQ (End, Seq);
//
// All the buffers in the SndQue are headless.
//
ASSERT (Nbuf->Tcp != NULL);
NetbufTrim (Nbuf, (Nbuf->Tcp->HeadLen << 2), NET_BUF_HEAD);
Nbuf->Tcp = NULL;
NetbufFree (Nbuf);
//
// Update the status in TCB.
//
Tcb->DelayedAck = 0;
if ((Flag & TCP_FLG_FIN) != 0) {
TCP_SET_FLG (Tcb->CtrlFlag, TCP_CTRL_FIN_SENT);
}
if (TCP_SEQ_GT (End, Tcb->SndNxt)) {
Tcb->SndNxt = End;
}
if (!TCP_TIMER_ON (Tcb->EnabledTimer, TCP_TIMER_REXMIT)) {
TcpSetTimer (Tcb, TCP_TIMER_REXMIT, Tcb->Rto);
}
//
// Enable RTT measurement only if not in retransmit.
// Karn's algorithm requires not to update RTT when in loss.
//
if ((Tcb->CongestState == TCP_CONGEST_OPEN) && !TCP_FLG_ON (Tcb->CtrlFlag, TCP_CTRL_RTT_ON)) {
DEBUG (
(DEBUG_NET,
"TcpToSendData: set RTT measure sequence %d for TCB %p\n",
Seq,
Tcb)
);
TCP_SET_FLG (Tcb->CtrlFlag, TCP_CTRL_RTT_ON);
Tcb->RttSeq = Seq;
Tcb->RttMeasure = 0;
}
} while (Len == Tcb->SndMss);
return Sent;
OnError:
if (Nbuf != NULL) {
NetbufFree (Nbuf);
}
return Sent;
}
/**
Send an ACK immediately.
@param[in, out] Tcb Pointer to the TCP_CB of this TCP instance.
**/
VOID
TcpSendAck (
IN OUT TCP_CB *Tcb
)
{
NET_BUF *Nbuf;
TCP_SEG *Seg;
Nbuf = NetbufAlloc (TCP_MAX_HEAD);
if (Nbuf == NULL) {
return;
}
NetbufReserve (Nbuf, TCP_MAX_HEAD);
Seg = TCPSEG_NETBUF (Nbuf);
Seg->Seq = Tcb->SndNxt;
Seg->End = Tcb->SndNxt;
Seg->Flag = TCP_FLG_ACK;
if (TcpTransmitSegment (Tcb, Nbuf) == 0) {
TCP_CLEAR_FLG (Tcb->CtrlFlag, TCP_CTRL_ACK_NOW);
Tcb->DelayedAck = 0;
}
NetbufFree (Nbuf);
}
/**
Send a zero probe segment. It can be used by keepalive and zero window probe.
@param[in, out] Tcb Pointer to the TCP_CB of this TCP instance.
@retval 0 The zero probe segment was sent out successfully.
@retval other An error condition occurred.
**/
INTN
TcpSendZeroProbe (
IN OUT TCP_CB *Tcb
)
{
NET_BUF *Nbuf;
TCP_SEG *Seg;
INTN Result;
Nbuf = NetbufAlloc (TCP_MAX_HEAD);
if (Nbuf == NULL) {
return -1;
}
NetbufReserve (Nbuf, TCP_MAX_HEAD);
//
// SndNxt-1 is out of window. The peer should respond
// with an ACK.
//
Seg = TCPSEG_NETBUF (Nbuf);
Seg->Seq = Tcb->SndNxt - 1;
Seg->End = Tcb->SndNxt - 1;
Seg->Flag = TCP_FLG_ACK;
Result = TcpTransmitSegment (Tcb, Nbuf);
NetbufFree (Nbuf);
return Result;
}
/**
Check whether to send an ACK or delayed ACK.
@param[in, out] Tcb Pointer to the TCP_CB of this TCP instance.
**/
VOID
TcpToSendAck (
IN OUT TCP_CB *Tcb
)
{
UINT32 TcpNow;
//
// Generally, TCP should send a delayed ACK unless:
// 1. ACK at least every other FULL sized segment received.
// 2. Packets received out of order.
// 3. Receiving window is open.
//
if (TCP_FLG_ON (Tcb->CtrlFlag, TCP_CTRL_ACK_NOW) || (Tcb->DelayedAck >= 1)) {
TcpSendAck (Tcb);
return;
}
TcpNow = TcpRcvWinNow (Tcb);
if (TcpNow > TcpRcvWinOld (Tcb)) {
TcpSendAck (Tcb);
return;
}
DEBUG (
(DEBUG_NET,
"TcpToSendAck: scheduled a delayed ACK for TCB %p\n",
Tcb)
);
//
// Schedule a delayed ACK.
//
Tcb->DelayedAck++;
}
/**
Send a RESET segment in response to the segment received.
@param[in] Tcb Pointer to the TCP_CB of this TCP instance. May be NULL.
@param[in] Head TCP header of the segment that triggers the reset.
@param[in] Len Length of the segment that triggers the reset.
@param[in] Local Local IP address.
@param[in] Remote Remote peer's IP address.
@param[in] Version IP_VERSION_4 indicates TCP is running on IP4 stack,
IP_VERSION_6 indicates TCP is running on IP6 stack.
@retval 0 A reset was sent or there is no need to send it.
@retval -1 No reset is sent.
**/
INTN
TcpSendReset (
IN TCP_CB *Tcb,
IN TCP_HEAD *Head,
IN INT32 Len,
IN EFI_IP_ADDRESS *Local,
IN EFI_IP_ADDRESS *Remote,
IN UINT8 Version
)
{
NET_BUF *Nbuf;
TCP_HEAD *Nhead;
UINT16 HeadSum;
//
// Don't respond to a Reset with reset.
//
if ((Head->Flag & TCP_FLG_RST) != 0) {
return 0;
}
Nbuf = NetbufAlloc (TCP_MAX_HEAD);
if (Nbuf == NULL) {
return -1;
}
Nhead = (TCP_HEAD *)NetbufAllocSpace (
Nbuf,
sizeof (TCP_HEAD),
NET_BUF_TAIL
);
ASSERT (Nhead != NULL);
Nbuf->Tcp = Nhead;
Nhead->Flag = TCP_FLG_RST;
//
// Derive Seq/ACK from the segment if no TCB
// is associated with it, otherwise derive from the Tcb.
//
if (Tcb == NULL) {
if (TCP_FLG_ON (Head->Flag, TCP_FLG_ACK)) {
Nhead->Seq = Head->Ack;
Nhead->Ack = 0;
} else {
Nhead->Seq = 0;
TCP_SET_FLG (Nhead->Flag, TCP_FLG_ACK);
Nhead->Ack = HTONL (NTOHL (Head->Seq) + Len);
}
} else {
Nhead->Seq = HTONL (Tcb->SndNxt);
Nhead->Ack = HTONL (Tcb->RcvNxt);
TCP_SET_FLG (Nhead->Flag, TCP_FLG_ACK);
}
Nhead->SrcPort = Head->DstPort;
Nhead->DstPort = Head->SrcPort;
Nhead->HeadLen = (UINT8)(sizeof (TCP_HEAD) >> 2);
Nhead->Res = 0;
Nhead->Wnd = HTONS (0xFFFF);
Nhead->Checksum = 0;
Nhead->Urg = 0;
if (Version == IP_VERSION_4) {
HeadSum = NetPseudoHeadChecksum (Local->Addr[0], Remote->Addr[0], 6, 0);
} else {
HeadSum = NetIp6PseudoHeadChecksum (&Local->v6, &Remote->v6, 6, 0);
}
Nhead->Checksum = TcpChecksum (Nbuf, HeadSum);
TcpSendIpPacket (Tcb, Nbuf, Local, Remote, Version);
NetbufFree (Nbuf);
return 0;
}
/**
Verify that the segment is in good shape.
@param[in] Nbuf The buffer that contains the segment to be checked.
@retval 0 The segment is broken.
@retval 1 The segment is in good shape.
**/
INTN
TcpVerifySegment (
IN NET_BUF *Nbuf
)
{
TCP_HEAD *Head;
TCP_SEG *Seg;
UINT32 Len;
if (Nbuf == NULL) {
return 1;
}
NET_CHECK_SIGNATURE (Nbuf, NET_BUF_SIGNATURE);
Seg = TCPSEG_NETBUF (Nbuf);
Len = Nbuf->TotalSize;
Head = Nbuf->Tcp;
if (Head != NULL) {
if (Head->Flag != Seg->Flag) {
return 0;
}
Len -= (Head->HeadLen << 2);
}
if (TCP_FLG_ON (Seg->Flag, TCP_FLG_SYN)) {
Len++;
}
if (TCP_FLG_ON (Seg->Flag, TCP_FLG_FIN)) {
Len++;
}
if (Seg->Seq + Len != Seg->End) {
return 0;
}
return 1;
}
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