/** @file | |
TCP input process routines. | |
Copyright (c) 2005 - 2010, Intel Corporation<BR> | |
All rights reserved. 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<BR> | |
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 "Tcp4Main.h" | |
/** | |
Check whether the sequence number of the incoming segment is acceptable. | |
@param Tcb Pointer to the TCP_CB of this TCP instance. | |
@param Seg Pointer to the incoming segment. | |
@retval 1 The sequence number is acceptable. | |
@retval 0 The sequence number is not acceptable. | |
**/ | |
INTN | |
TcpSeqAcceptable ( | |
IN TCP_CB *Tcb, | |
IN TCP_SEG *Seg | |
) | |
{ | |
return (TCP_SEQ_LEQ (Tcb->RcvWl2, Seg->End) && | |
TCP_SEQ_LT (Seg->Seq, Tcb->RcvWl2 + Tcb->RcvWnd)); | |
} | |
/** | |
NewReno fast recovery, RFC3782. | |
@param Tcb Pointer to the TCP_CB of this TCP instance. | |
@param Seg Segment that triggers the fast recovery. | |
**/ | |
VOID | |
TcpFastRecover ( | |
IN OUT TCP_CB *Tcb, | |
IN TCP_SEG *Seg | |
) | |
{ | |
UINT32 FlightSize; | |
UINT32 Acked; | |
// | |
// Step 1: Three duplicate ACKs and not in fast recovery | |
// | |
if (Tcb->CongestState != TCP_CONGEST_RECOVER) { | |
// | |
// Step 1A: Invoking fast retransmission. | |
// | |
FlightSize = TCP_SUB_SEQ (Tcb->SndNxt, Tcb->SndUna); | |
Tcb->Ssthresh = MAX (FlightSize >> 1, (UINT32) (2 * Tcb->SndMss)); | |
Tcb->Recover = Tcb->SndNxt; | |
Tcb->CongestState = TCP_CONGEST_RECOVER; | |
TCP_CLEAR_FLG (Tcb->CtrlFlag, TCP_CTRL_RTT_ON); | |
// | |
// Step 2: Entering fast retransmission | |
// | |
TcpRetransmit (Tcb, Tcb->SndUna); | |
Tcb->CWnd = Tcb->Ssthresh + 3 * Tcb->SndMss; | |
DEBUG ((EFI_D_INFO, "TcpFastRecover: enter fast retransmission" | |
" for TCB %p, recover point is %d\n", Tcb, Tcb->Recover)); | |
return; | |
} | |
// | |
// During fast recovery, execute Step 3, 4, 5 of RFC3782 | |
// | |
if (Seg->Ack == Tcb->SndUna) { | |
// | |
// Step 3: Fast Recovery, | |
// If this is a duplicated ACK, increse Cwnd by SMSS. | |
// | |
// Step 4 is skipped here only to be executed later | |
// by TcpToSendData | |
// | |
Tcb->CWnd += Tcb->SndMss; | |
DEBUG ((EFI_D_INFO, "TcpFastRecover: received another" | |
" duplicated ACK (%d) for TCB %p\n", Seg->Ack, Tcb)); | |
} else { | |
// | |
// New data is ACKed, check whether it is a | |
// full ACK or partial ACK | |
// | |
if (TCP_SEQ_GEQ (Seg->Ack, Tcb->Recover)) { | |
// | |
// Step 5 - Full ACK: | |
// deflate the congestion window, and exit fast recovery | |
// | |
FlightSize = TCP_SUB_SEQ (Tcb->SndNxt, Tcb->SndUna); | |
Tcb->CWnd = MIN (Tcb->Ssthresh, FlightSize + Tcb->SndMss); | |
Tcb->CongestState = TCP_CONGEST_OPEN; | |
DEBUG ((EFI_D_INFO, "TcpFastRecover: received a full ACK(%d)" | |
" for TCB %p, exit fast recovery\n", Seg->Ack, Tcb)); | |
} else { | |
// | |
// Step 5 - Partial ACK: | |
// fast retransmit the first unacknowledge field | |
// , then deflate the CWnd | |
// | |
TcpRetransmit (Tcb, Seg->Ack); | |
Acked = TCP_SUB_SEQ (Seg->Ack, Tcb->SndUna); | |
// | |
// Deflate the CWnd by the amount of new data | |
// ACKed by SEG.ACK. If more than one SMSS data | |
// is ACKed, add back SMSS byte to CWnd after | |
// | |
if (Acked >= Tcb->SndMss) { | |
Acked -= Tcb->SndMss; | |
} | |
Tcb->CWnd -= Acked; | |
DEBUG ((EFI_D_INFO, "TcpFastRecover: received a partial" | |
" ACK(%d) for TCB %p\n", Seg->Ack, Tcb)); | |
} | |
} | |
} | |
/** | |
NewReno fast loss recovery, RFC3792. | |
@param Tcb Pointer to the TCP_CB of this TCP instance. | |
@param Seg Segment that triggers the fast loss recovery. | |
**/ | |
VOID | |
TcpFastLossRecover ( | |
IN OUT TCP_CB *Tcb, | |
IN TCP_SEG *Seg | |
) | |
{ | |
if (TCP_SEQ_GT (Seg->Ack, Tcb->SndUna)) { | |
// | |
// New data is ACKed, check whether it is a | |
// full ACK or partial ACK | |
// | |
if (TCP_SEQ_GEQ (Seg->Ack, Tcb->LossRecover)) { | |
// | |
// Full ACK: exit the loss recovery. | |
// | |
Tcb->LossTimes = 0; | |
Tcb->CongestState = TCP_CONGEST_OPEN; | |
DEBUG ((EFI_D_INFO, "TcpFastLossRecover: received a " | |
"full ACK(%d) for TCB %p\n", Seg->Ack, Tcb)); | |
} else { | |
// | |
// Partial ACK: | |
// fast retransmit the first unacknowledge field. | |
// | |
TcpRetransmit (Tcb, Seg->Ack); | |
DEBUG ((EFI_D_INFO, "TcpFastLossRecover: received a " | |
"partial ACK(%d) for TCB %p\n", Seg->Ack, Tcb)); | |
} | |
} | |
} | |
/** | |
Compute the RTT as specified in RFC2988. | |
@param Tcb Pointer to the TCP_CB of this TCP instance. | |
@param Measure Currently measured RTT in heart beats. | |
**/ | |
VOID | |
TcpComputeRtt ( | |
IN OUT TCP_CB *Tcb, | |
IN UINT32 Measure | |
) | |
{ | |
INT32 Var; | |
// | |
// Step 2.3: Compute the RTO for subsequent RTT measurement. | |
// | |
if (Tcb->SRtt != 0) { | |
Var = Tcb->SRtt - (Measure << TCP_RTT_SHIFT); | |
if (Var < 0) { | |
Var = -Var; | |
} | |
Tcb->RttVar = (3 * Tcb->RttVar + Var) >> 2; | |
Tcb->SRtt = 7 * (Tcb->SRtt >> 3) + Measure; | |
} else { | |
// | |
// Step 2.2: compute the first RTT measure | |
// | |
Tcb->SRtt = Measure << TCP_RTT_SHIFT; | |
Tcb->RttVar = Measure << (TCP_RTT_SHIFT - 1); | |
} | |
Tcb->Rto = (Tcb->SRtt + MAX (8, 4 * Tcb->RttVar)) >> TCP_RTT_SHIFT; | |
// | |
// Step 2.4: Limit the RTO to at least 1 second | |
// Step 2.5: Limit the RTO to a maxium value that | |
// is at least 60 second | |
// | |
if (Tcb->Rto < TCP_RTO_MIN) { | |
Tcb->Rto = TCP_RTO_MIN; | |
} else if (Tcb->Rto > TCP_RTO_MAX) { | |
Tcb->Rto = TCP_RTO_MAX; | |
} | |
DEBUG ((EFI_D_INFO, "TcpComputeRtt: new RTT for TCB %p" | |
" computed SRTT: %d RTTVAR: %d RTO: %d\n", | |
Tcb, Tcb->SRtt, Tcb->RttVar, Tcb->Rto)); | |
} | |
/** | |
Trim the data, SYN and FIN to fit into the window defined by Left and Right. | |
@param Nbuf Buffer that contains received TCP segment without IP header. | |
@param Left The sequence number of the window's left edge. | |
@param Right The sequence number of the window's right edge. | |
**/ | |
VOID | |
TcpTrimSegment ( | |
IN NET_BUF *Nbuf, | |
IN TCP_SEQNO Left, | |
IN TCP_SEQNO Right | |
) | |
{ | |
TCP_SEG *Seg; | |
TCP_SEQNO Urg; | |
UINT32 Drop; | |
Seg = TCPSEG_NETBUF (Nbuf); | |
// | |
// If the segment is completely out of window, | |
// truncate every thing, include SYN and FIN. | |
// | |
if (TCP_SEQ_LEQ (Seg->End, Left) || TCP_SEQ_LEQ (Right, Seg->Seq)) { | |
TCP_CLEAR_FLG (Seg->Flag, TCP_FLG_SYN); | |
TCP_CLEAR_FLG (Seg->Flag, TCP_FLG_FIN); | |
Seg->Seq = Seg->End; | |
NetbufTrim (Nbuf, Nbuf->TotalSize, NET_BUF_HEAD); | |
return; | |
} | |
// | |
// Adjust the buffer header | |
// | |
if (TCP_SEQ_LT (Seg->Seq, Left)) { | |
Drop = TCP_SUB_SEQ (Left, Seg->Seq); | |
Urg = Seg->Seq + Seg->Urg; | |
Seg->Seq = Left; | |
if (TCP_FLG_ON (Seg->Flag, TCP_FLG_SYN)) { | |
TCP_CLEAR_FLG (Seg->Flag, TCP_FLG_SYN); | |
Drop--; | |
} | |
// | |
// Adjust the urgent point | |
// | |
if (TCP_FLG_ON (Seg->Flag, TCP_FLG_URG)) { | |
if (TCP_SEQ_LT (Urg, Seg->Seq)) { | |
TCP_CLEAR_FLG (Seg->Flag, TCP_FLG_URG); | |
} else { | |
Seg->Urg = (UINT16) TCP_SUB_SEQ (Urg, Seg->Seq); | |
} | |
} | |
if (Drop != 0) { | |
NetbufTrim (Nbuf, Drop, NET_BUF_HEAD); | |
} | |
} | |
// | |
// Adjust the buffer tail | |
// | |
if (TCP_SEQ_GT (Seg->End, Right)) { | |
Drop = TCP_SUB_SEQ (Seg->End, Right); | |
Seg->End = Right; | |
if (TCP_FLG_ON (Seg->Flag, TCP_FLG_FIN)) { | |
TCP_CLEAR_FLG (Seg->Flag, TCP_FLG_FIN); | |
Drop--; | |
} | |
if (Drop != 0) { | |
NetbufTrim (Nbuf, Drop, NET_BUF_TAIL); | |
} | |
} | |
ASSERT (TcpVerifySegment (Nbuf) != 0); | |
} | |
/** | |
Trim off the data outside the tcb's receive window. | |
@param Tcb Pointer to the TCP_CB of this TCP instance. | |
@param Nbuf Pointer to the NET_BUF containing the received tcp segment. | |
**/ | |
VOID | |
TcpTrimInWnd ( | |
IN TCP_CB *Tcb, | |
IN NET_BUF *Nbuf | |
) | |
{ | |
TcpTrimSegment (Nbuf, Tcb->RcvNxt, Tcb->RcvWl2 + Tcb->RcvWnd); | |
} | |
/** | |
Process the data and FIN flag, check whether to deliver | |
data to the socket layer. | |
@param Tcb Pointer to the TCP_CB of this TCP instance. | |
@retval 0 No error occurred to deliver data. | |
@retval -1 Error condition occurred. Proper response is to reset the | |
connection. | |
**/ | |
INTN | |
TcpDeliverData ( | |
IN OUT TCP_CB *Tcb | |
) | |
{ | |
LIST_ENTRY *Entry; | |
NET_BUF *Nbuf; | |
TCP_SEQNO Seq; | |
TCP_SEG *Seg; | |
UINT32 Urgent; | |
ASSERT ((Tcb != NULL) && (Tcb->Sk != NULL)); | |
// | |
// make sure there is some data queued, | |
// and TCP is in a proper state | |
// | |
if (IsListEmpty (&Tcb->RcvQue) || !TCP_CONNECTED (Tcb->State)) { | |
return 0; | |
} | |
// | |
// Deliver data to the socket layer | |
// | |
Entry = Tcb->RcvQue.ForwardLink; | |
Seq = Tcb->RcvNxt; | |
while (Entry != &Tcb->RcvQue) { | |
Nbuf = NET_LIST_USER_STRUCT (Entry, NET_BUF, List); | |
Seg = TCPSEG_NETBUF (Nbuf); | |
ASSERT (TcpVerifySegment (Nbuf) != 0); | |
ASSERT (Nbuf->Tcp == NULL); | |
if (TCP_SEQ_GT (Seg->Seq, Seq)) { | |
break; | |
} | |
Entry = Entry->ForwardLink; | |
Seq = Seg->End; | |
Tcb->RcvNxt = Seq; | |
RemoveEntryList (&Nbuf->List); | |
// | |
// RFC793 Eighth step: process FIN in sequence | |
// | |
if (TCP_FLG_ON (Seg->Flag, TCP_FLG_FIN)) { | |
// | |
// The peer sends to us junky data after FIN, | |
// reset the connection. | |
// | |
if (!IsListEmpty (&Tcb->RcvQue)) { | |
DEBUG ((EFI_D_ERROR, "TcpDeliverData: data received after" | |
" FIN from peer of TCB %p, reset connection\n", Tcb)); | |
NetbufFree (Nbuf); | |
return -1; | |
} | |
DEBUG ((EFI_D_INFO, "TcpDeliverData: processing FIN " | |
"from peer of TCB %p\n", Tcb)); | |
switch (Tcb->State) { | |
case TCP_SYN_RCVD: | |
case TCP_ESTABLISHED: | |
TcpSetState (Tcb, TCP_CLOSE_WAIT); | |
break; | |
case TCP_FIN_WAIT_1: | |
if (!TCP_FLG_ON (Tcb->CtrlFlag, TCP_CTRL_FIN_ACKED)) { | |
TcpSetState (Tcb, TCP_CLOSING); | |
break; | |
} | |
// | |
// fall through | |
// | |
case TCP_FIN_WAIT_2: | |
TcpSetState (Tcb, TCP_TIME_WAIT); | |
TcpClearAllTimer (Tcb); | |
if (Tcb->TimeWaitTimeout != 0) { | |
TcpSetTimer (Tcb, TCP_TIMER_2MSL, Tcb->TimeWaitTimeout); | |
} else { | |
DEBUG ((EFI_D_WARN, "Connection closed immediately " | |
"because app disables TIME_WAIT timer for %p\n", Tcb)); | |
TcpSendAck (Tcb); | |
TcpClose (Tcb); | |
} | |
break; | |
case TCP_CLOSE_WAIT: | |
case TCP_CLOSING: | |
case TCP_LAST_ACK: | |
case TCP_TIME_WAIT: | |
// | |
// The peer sends to us junk FIN byte. Discard | |
// the buffer then reset the connection | |
// | |
NetbufFree (Nbuf); | |
return -1; | |
break; | |
default: | |
break; | |
} | |
TCP_SET_FLG (Tcb->CtrlFlag, TCP_CTRL_ACK_NOW); | |
Seg->End--; | |
} | |
// | |
// Don't delay the ack if PUSH flag is on. | |
// | |
if (TCP_FLG_ON (Seg->Flag, TCP_FLG_PSH)) { | |
TCP_SET_FLG (Tcb->CtrlFlag, TCP_CTRL_ACK_NOW); | |
} | |
if (Nbuf->TotalSize != 0) { | |
Urgent = 0; | |
if (TCP_FLG_ON (Tcb->CtrlFlag, TCP_CTRL_RCVD_URG) && | |
TCP_SEQ_LEQ (Seg->Seq, Tcb->RcvUp)) { | |
if (TCP_SEQ_LEQ (Seg->End, Tcb->RcvUp)) { | |
Urgent = Nbuf->TotalSize; | |
} else { | |
Urgent = TCP_SUB_SEQ (Tcb->RcvUp, Seg->Seq) + 1; | |
} | |
} | |
SockDataRcvd (Tcb->Sk, Nbuf, Urgent); | |
} | |
if (TCP_FIN_RCVD (Tcb->State)) { | |
SockNoMoreData (Tcb->Sk); | |
} | |
NetbufFree (Nbuf); | |
} | |
return 0; | |
} | |
/** | |
Store the data into the reassemble queue. | |
@param Tcb Pointer to the TCP_CB of this TCP instance. | |
@param Nbuf Pointer to the buffer containing the data to be queued. | |
**/ | |
VOID | |
TcpQueueData ( | |
IN OUT TCP_CB *Tcb, | |
IN NET_BUF *Nbuf | |
) | |
{ | |
TCP_SEG *Seg; | |
LIST_ENTRY *Head; | |
LIST_ENTRY *Prev; | |
LIST_ENTRY *Cur; | |
NET_BUF *Node; | |
ASSERT ((Tcb != NULL) && (Nbuf != NULL) && (Nbuf->Tcp == NULL)); | |
NET_GET_REF (Nbuf); | |
Seg = TCPSEG_NETBUF (Nbuf); | |
Head = &Tcb->RcvQue; | |
// | |
// Fast path to process normal case. That is, | |
// no out-of-order segments are received. | |
// | |
if (IsListEmpty (Head)) { | |
InsertTailList (Head, &Nbuf->List); | |
return ; | |
} | |
// | |
// Find the point to insert the buffer | |
// | |
for (Prev = Head, Cur = Head->ForwardLink; | |
Cur != Head; | |
Prev = Cur, Cur = Cur->ForwardLink) { | |
Node = NET_LIST_USER_STRUCT (Cur, NET_BUF, List); | |
if (TCP_SEQ_LT (Seg->Seq, TCPSEG_NETBUF (Node)->Seq)) { | |
break; | |
} | |
} | |
// | |
// Check whether the current segment overlaps with the | |
// previous segment. | |
// | |
if (Prev != Head) { | |
Node = NET_LIST_USER_STRUCT (Prev, NET_BUF, List); | |
if (TCP_SEQ_LT (Seg->Seq, TCPSEG_NETBUF (Node)->End)) { | |
if (TCP_SEQ_LEQ (Seg->End, TCPSEG_NETBUF (Node)->End)) { | |
NetbufFree (Nbuf); | |
return ; | |
} | |
TcpTrimSegment (Nbuf, TCPSEG_NETBUF (Node)->End, Seg->End); | |
} | |
} | |
InsertHeadList (Prev, &Nbuf->List); | |
TCP_SET_FLG (Tcb->CtrlFlag, TCP_CTRL_ACK_NOW); | |
// | |
// Check the segments after the insert point. | |
// | |
while (Cur != Head) { | |
Node = NET_LIST_USER_STRUCT (Cur, NET_BUF, List); | |
if (TCP_SEQ_LEQ (TCPSEG_NETBUF (Node)->End, Seg->End)) { | |
Cur = Cur->ForwardLink; | |
RemoveEntryList (&Node->List); | |
NetbufFree (Node); | |
continue; | |
} | |
if (TCP_SEQ_LT (TCPSEG_NETBUF (Node)->Seq, Seg->End)) { | |
if (TCP_SEQ_LEQ (TCPSEG_NETBUF (Node)->Seq, Seg->Seq)) { | |
RemoveEntryList (&Nbuf->List); | |
NetbufFree (Nbuf); | |
return ; | |
} | |
TcpTrimSegment (Nbuf, Seg->Seq, TCPSEG_NETBUF (Node)->Seq); | |
break; | |
} | |
Cur = Cur->ForwardLink; | |
} | |
} | |
/** | |
Ajust the send queue or the retransmit queue. | |
@param Tcb Pointer to the TCP_CB of this TCP instance. | |
@param Ack The acknowledge seuqence number of the received segment. | |
**/ | |
VOID | |
TcpAdjustSndQue ( | |
IN TCP_CB *Tcb, | |
IN TCP_SEQNO Ack | |
) | |
{ | |
LIST_ENTRY *Head; | |
LIST_ENTRY *Cur; | |
NET_BUF *Node; | |
TCP_SEG *Seg; | |
Head = &Tcb->SndQue; | |
Cur = Head->ForwardLink; | |
while (Cur != Head) { | |
Node = NET_LIST_USER_STRUCT (Cur, NET_BUF, List); | |
Seg = TCPSEG_NETBUF (Node); | |
if (TCP_SEQ_GEQ (Seg->Seq, Ack)) { | |
break; | |
} | |
// | |
// Remove completely ACKed segments | |
// | |
if (TCP_SEQ_LEQ (Seg->End, Ack)) { | |
Cur = Cur->ForwardLink; | |
RemoveEntryList (&Node->List); | |
NetbufFree (Node); | |
continue; | |
} | |
TcpTrimSegment (Node, Ack, Seg->End); | |
break; | |
} | |
} | |
/** | |
Process the received TCP segments. | |
@param Nbuf Buffer that contains received TCP segment without IP header. | |
@param Src Source address of the segment, or the peer's IP address. | |
@param Dst Destination address of the segment, or the local end's IP | |
address. | |
@retval 0 Segment is processed successfully. It is either accepted or | |
discarded. But no connection is reset by the segment. | |
@retval -1 A connection is reset by the segment. | |
**/ | |
INTN | |
TcpInput ( | |
IN NET_BUF *Nbuf, | |
IN UINT32 Src, | |
IN UINT32 Dst | |
) | |
{ | |
TCP_CB *Tcb; | |
TCP_CB *Parent; | |
TCP_OPTION Option; | |
TCP_HEAD *Head; | |
INT32 Len; | |
TCP_SEG *Seg; | |
TCP_SEQNO Right; | |
TCP_SEQNO Urg; | |
NET_CHECK_SIGNATURE (Nbuf, NET_BUF_SIGNATURE); | |
Parent = NULL; | |
Tcb = NULL; | |
Head = (TCP_HEAD *) NetbufGetByte (Nbuf, 0, NULL); | |
Len = Nbuf->TotalSize - (Head->HeadLen << 2); | |
if ((Head->HeadLen < 5) || (Len < 0) || | |
(TcpChecksum (Nbuf, NetPseudoHeadChecksum (Src, Dst, 6, 0)) != 0)) { | |
DEBUG ((EFI_D_INFO, "TcpInput: received an mal-formated packet\n")); | |
goto DISCARD; | |
} | |
if (TCP_FLG_ON (Head->Flag, TCP_FLG_SYN)) { | |
Len++; | |
} | |
if (TCP_FLG_ON (Head->Flag, TCP_FLG_FIN)) { | |
Len++; | |
} | |
Tcb = TcpLocateTcb ( | |
Head->DstPort, | |
Dst, | |
Head->SrcPort, | |
Src, | |
(BOOLEAN) TCP_FLG_ON (Head->Flag, TCP_FLG_SYN) | |
); | |
if ((Tcb == NULL) || (Tcb->State == TCP_CLOSED)) { | |
DEBUG ((EFI_D_INFO, "TcpInput: send reset because no TCB find\n")); | |
Tcb = NULL; | |
goto SEND_RESET; | |
} | |
Seg = TcpFormatNetbuf (Tcb, Nbuf); | |
// | |
// RFC1122 recommended reaction to illegal option | |
// (in fact, an illegal option length) is reset. | |
// | |
if (TcpParseOption (Nbuf->Tcp, &Option) == -1) { | |
DEBUG ((EFI_D_ERROR, "TcpInput: reset the peer because" | |
" of mal-format option for Tcb %p\n", Tcb)); | |
goto SEND_RESET; | |
} | |
// | |
// From now on, the segment is headless | |
// | |
NetbufTrim (Nbuf, (Head->HeadLen << 2), NET_BUF_HEAD); | |
Nbuf->Tcp = NULL; | |
// | |
// Process the segment in LISTEN state. | |
// | |
if (Tcb->State == TCP_LISTEN) { | |
// | |
// First step: Check RST | |
// | |
if (TCP_FLG_ON (Seg->Flag, TCP_FLG_RST)) { | |
DEBUG ((EFI_D_WARN, "TcpInput: discard a reset segment " | |
"for TCB %p in listening\n", Tcb)); | |
goto DISCARD; | |
} | |
// | |
// Second step: Check ACK. | |
// Any ACK sent to TCP in LISTEN is reseted. | |
// | |
if (TCP_FLG_ON (Seg->Flag, TCP_FLG_ACK)) { | |
DEBUG ((EFI_D_WARN, "TcpInput: send reset because of" | |
" segment with ACK for TCB %p in listening\n", Tcb)); | |
goto SEND_RESET; | |
} | |
// | |
// Third step: Check SYN | |
// | |
if (TCP_FLG_ON (Seg->Flag, TCP_FLG_SYN)) { | |
// | |
// create a child TCB to handle the data | |
// | |
Parent = Tcb; | |
Tcb = TcpCloneTcb (Parent); | |
if (Tcb == NULL) { | |
DEBUG ((EFI_D_ERROR, "TcpInput: discard a segment because" | |
"failed to clone a child for TCB%x\n", Tcb)); | |
goto DISCARD; | |
} | |
DEBUG ((EFI_D_INFO, "TcpInput: create a child for TCB %p" | |
" in listening\n", Tcb)); | |
// | |
// init the TCB structure | |
// | |
Tcb->LocalEnd.Ip = Dst; | |
Tcb->LocalEnd.Port = Head->DstPort; | |
Tcb->RemoteEnd.Ip = Src; | |
Tcb->RemoteEnd.Port = Head->SrcPort; | |
TcpInitTcbLocal (Tcb); | |
TcpInitTcbPeer (Tcb, Seg, &Option); | |
TcpSetState (Tcb, TCP_SYN_RCVD); | |
TcpSetTimer (Tcb, TCP_TIMER_CONNECT, Tcb->ConnectTimeout); | |
TcpTrimInWnd (Tcb, Nbuf); | |
goto StepSix; | |
} | |
goto DISCARD; | |
} else if (Tcb->State == TCP_SYN_SENT) { | |
// | |
// First step: Check ACK bit | |
// | |
if (TCP_FLG_ON (Seg->Flag, TCP_FLG_ACK) && (Seg->Ack != Tcb->Iss + 1)) { | |
DEBUG ((EFI_D_WARN, "TcpInput: send reset because of " | |
"wrong ACK received for TCB %p in SYN_SENT\n", Tcb)); | |
goto SEND_RESET; | |
} | |
// | |
// Second step: Check RST bit | |
// | |
if (TCP_FLG_ON (Seg->Flag, TCP_FLG_RST)) { | |
if (TCP_FLG_ON (Seg->Flag, TCP_FLG_ACK)) { | |
DEBUG ((EFI_D_WARN, "TcpInput: connection reset by" | |
" peer for TCB %p in SYN_SENT\n", Tcb)); | |
SOCK_ERROR (Tcb->Sk, EFI_CONNECTION_RESET); | |
goto DROP_CONNECTION; | |
} else { | |
DEBUG ((EFI_D_WARN, "TcpInput: discard a reset segment " | |
"because of no ACK for TCB %p in SYN_SENT\n", Tcb)); | |
goto DISCARD; | |
} | |
} | |
// | |
// Third step: Check security and precedence. Skipped | |
// | |
// | |
// Fourth step: Check SYN. Pay attention to sitimulatous open | |
// | |
if (TCP_FLG_ON (Seg->Flag, TCP_FLG_SYN)) { | |
TcpInitTcbPeer (Tcb, Seg, &Option); | |
if (TCP_FLG_ON (Seg->Flag, TCP_FLG_ACK)) { | |
Tcb->SndUna = Seg->Ack; | |
} | |
TcpClearTimer (Tcb, TCP_TIMER_REXMIT); | |
if (TCP_SEQ_GT (Tcb->SndUna, Tcb->Iss)) { | |
TcpSetState (Tcb, TCP_ESTABLISHED); | |
TcpClearTimer (Tcb, TCP_TIMER_CONNECT); | |
TcpDeliverData (Tcb); | |
if ((Tcb->CongestState == TCP_CONGEST_OPEN) && | |
TCP_FLG_ON (Tcb->CtrlFlag, TCP_CTRL_RTT_ON)) { | |
TcpComputeRtt (Tcb, Tcb->RttMeasure); | |
TCP_CLEAR_FLG (Tcb->CtrlFlag, TCP_CTRL_RTT_ON); | |
} | |
TcpTrimInWnd (Tcb, Nbuf); | |
TCP_SET_FLG (Tcb->CtrlFlag, TCP_CTRL_ACK_NOW); | |
DEBUG ((EFI_D_INFO, "TcpInput: connection established" | |
" for TCB %p in SYN_SENT\n", Tcb)); | |
goto StepSix; | |
} else { | |
// | |
// Received a SYN segment without ACK, simultanous open. | |
// | |
TcpSetState (Tcb, TCP_SYN_RCVD); | |
ASSERT (Tcb->SndNxt == Tcb->Iss + 1); | |
TcpAdjustSndQue (Tcb, Tcb->SndNxt); | |
TcpTrimInWnd (Tcb, Nbuf); | |
DEBUG ((EFI_D_WARN, "TcpInput: simultanous open " | |
"for TCB %p in SYN_SENT\n", Tcb)); | |
goto StepSix; | |
} | |
} | |
goto DISCARD; | |
} | |
// | |
// Process segment in SYN_RCVD or TCP_CONNECTED states | |
// | |
// | |
// Clear probe timer since the RecvWindow is opened. | |
// | |
if (Tcb->ProbeTimerOn && (Seg->Wnd != 0)) { | |
TcpClearTimer (Tcb, TCP_TIMER_PROBE); | |
Tcb->ProbeTimerOn = FALSE; | |
} | |
// | |
// First step: Check whether SEG.SEQ is acceptable | |
// | |
if (TcpSeqAcceptable (Tcb, Seg) == 0) { | |
DEBUG ((EFI_D_WARN, "TcpInput: sequence acceptance" | |
" test failed for segment of TCB %p\n", Tcb)); | |
if (!TCP_FLG_ON (Seg->Flag, TCP_FLG_RST)) { | |
TcpSendAck (Tcb); | |
} | |
goto DISCARD; | |
} | |
if ((TCP_SEQ_LT (Seg->Seq, Tcb->RcvWl2)) && | |
(Tcb->RcvWl2 == Seg->End) && | |
!TCP_FLG_ON (Seg->Flag, TCP_FLG_SYN | TCP_FLG_FIN)) { | |
TCP_SET_FLG (Tcb->CtrlFlag, TCP_CTRL_ACK_NOW); | |
} | |
// | |
// Second step: Check the RST | |
// | |
if (TCP_FLG_ON (Seg->Flag, TCP_FLG_RST)) { | |
DEBUG ((EFI_D_WARN, "TcpInput: connection reset for TCB %p\n", Tcb)); | |
if (Tcb->State == TCP_SYN_RCVD) { | |
SOCK_ERROR (Tcb->Sk, EFI_CONNECTION_REFUSED); | |
// | |
// This TCB comes from either a LISTEN TCB, | |
// or active open TCB with simultanous open. | |
// Do NOT signal user CONNECTION refused | |
// if it comes from a LISTEN TCB. | |
// | |
} else if ((Tcb->State == TCP_ESTABLISHED) || | |
(Tcb->State == TCP_FIN_WAIT_1) || | |
(Tcb->State == TCP_FIN_WAIT_2) || | |
(Tcb->State == TCP_CLOSE_WAIT)) { | |
SOCK_ERROR (Tcb->Sk, EFI_CONNECTION_RESET); | |
} else { | |
} | |
goto DROP_CONNECTION; | |
} | |
// | |
// Trim the data and flags. | |
// | |
TcpTrimInWnd (Tcb, Nbuf); | |
// | |
// Third step: Check security and precedence, Ignored | |
// | |
// | |
// Fourth step: Check the SYN bit. | |
// | |
if (TCP_FLG_ON (Seg->Flag, TCP_FLG_SYN)) { | |
DEBUG ((EFI_D_WARN, "TcpInput: connection reset " | |
"because received extra SYN for TCB %p\n", Tcb)); | |
SOCK_ERROR (Tcb->Sk, EFI_CONNECTION_RESET); | |
goto RESET_THEN_DROP; | |
} | |
// | |
// Fifth step: Check the ACK | |
// | |
if (!TCP_FLG_ON (Seg->Flag, TCP_FLG_ACK)) { | |
DEBUG ((EFI_D_WARN, "TcpInput: segment discard because" | |
" of no ACK for connected TCB %p\n", Tcb)); | |
goto DISCARD; | |
} | |
if (Tcb->State == TCP_SYN_RCVD) { | |
if (TCP_SEQ_LT (Tcb->SndUna, Seg->Ack) && | |
TCP_SEQ_LEQ (Seg->Ack, Tcb->SndNxt)) { | |
Tcb->SndWnd = Seg->Wnd; | |
Tcb->SndWndMax = MAX (Tcb->SndWnd, Tcb->SndWndMax); | |
Tcb->SndWl1 = Seg->Seq; | |
Tcb->SndWl2 = Seg->Ack; | |
TcpSetState (Tcb, TCP_ESTABLISHED); | |
TcpClearTimer (Tcb, TCP_TIMER_CONNECT); | |
TcpDeliverData (Tcb); | |
DEBUG ((EFI_D_INFO, "TcpInput: connection established " | |
" for TCB %p in SYN_RCVD\n", Tcb)); | |
// | |
// Continue the process as ESTABLISHED state | |
// | |
} else { | |
DEBUG ((EFI_D_WARN, "TcpInput: send reset because of" | |
" wrong ACK for TCB %p in SYN_RCVD\n", Tcb)); | |
goto SEND_RESET; | |
} | |
} | |
if (TCP_SEQ_LT (Seg->Ack, Tcb->SndUna)) { | |
DEBUG ((EFI_D_WARN, "TcpInput: ignore the out-of-data" | |
" ACK for connected TCB %p\n", Tcb)); | |
goto StepSix; | |
} else if (TCP_SEQ_GT (Seg->Ack, Tcb->SndNxt)) { | |
DEBUG ((EFI_D_WARN, "TcpInput: discard segment for " | |
"future ACK for connected TCB %p\n", Tcb)); | |
TcpSendAck (Tcb); | |
goto DISCARD; | |
} | |
// | |
// From now on: SND.UNA <= SEG.ACK <= SND.NXT. | |
// | |
if (TCP_FLG_ON (Option.Flag, TCP_OPTION_RCVD_TS)) { | |
// | |
// update TsRecent as specified in page 16 RFC1323. | |
// RcvWl2 equals to the variable "LastAckSent" | |
// defined there. | |
// | |
if (TCP_SEQ_LEQ (Seg->Seq, Tcb->RcvWl2) && | |
TCP_SEQ_LT (Tcb->RcvWl2, Seg->End)) { | |
Tcb->TsRecent = Option.TSVal; | |
Tcb->TsRecentAge = mTcpTick; | |
} | |
TcpComputeRtt (Tcb, TCP_SUB_TIME (mTcpTick, Option.TSEcr)); | |
} else if (TCP_FLG_ON (Tcb->CtrlFlag, TCP_CTRL_RTT_ON)) { | |
ASSERT (Tcb->CongestState == TCP_CONGEST_OPEN); | |
TcpComputeRtt (Tcb, Tcb->RttMeasure); | |
TCP_CLEAR_FLG (Tcb->CtrlFlag, TCP_CTRL_RTT_ON); | |
} | |
if (Seg->Ack == Tcb->SndNxt) { | |
TcpClearTimer (Tcb, TCP_TIMER_REXMIT); | |
} else { | |
TcpSetTimer (Tcb, TCP_TIMER_REXMIT, Tcb->Rto); | |
} | |
// | |
// Count duplicate acks. | |
// | |
if ((Seg->Ack == Tcb->SndUna) && | |
(Tcb->SndUna != Tcb->SndNxt) && | |
(Seg->Wnd == Tcb->SndWnd) && | |
(0 == Len)) { | |
Tcb->DupAck++; | |
} else { | |
Tcb->DupAck = 0; | |
} | |
// | |
// Congestion avoidance, fast recovery and fast retransmission. | |
// | |
if (((Tcb->CongestState == TCP_CONGEST_OPEN) && (Tcb->DupAck < 3)) || | |
(Tcb->CongestState == TCP_CONGEST_LOSS)) { | |
if (TCP_SEQ_GT (Seg->Ack, Tcb->SndUna)) { | |
if (Tcb->CWnd < Tcb->Ssthresh) { | |
Tcb->CWnd += Tcb->SndMss; | |
} else { | |
Tcb->CWnd += MAX (Tcb->SndMss * Tcb->SndMss / Tcb->CWnd, 1); | |
} | |
Tcb->CWnd = MIN (Tcb->CWnd, TCP_MAX_WIN << Tcb->SndWndScale); | |
} | |
if (Tcb->CongestState == TCP_CONGEST_LOSS) { | |
TcpFastLossRecover (Tcb, Seg); | |
} | |
} else { | |
TcpFastRecover (Tcb, Seg); | |
} | |
if (TCP_SEQ_GT (Seg->Ack, Tcb->SndUna)) { | |
TcpAdjustSndQue (Tcb, Seg->Ack); | |
Tcb->SndUna = Seg->Ack; | |
if (TCP_FLG_ON (Tcb->CtrlFlag, TCP_CTRL_SND_URG) && | |
TCP_SEQ_LT (Tcb->SndUp, Seg->Ack)) { | |
TCP_CLEAR_FLG (Tcb->CtrlFlag, TCP_CTRL_SND_URG); | |
} | |
} | |
// | |
// Update window info | |
// | |
if (TCP_SEQ_LT (Tcb->SndWl1, Seg->Seq) || | |
((Tcb->SndWl1 == Seg->Seq) && TCP_SEQ_LEQ (Tcb->SndWl2, Seg->Ack))) { | |
Right = Seg->Ack + Seg->Wnd; | |
if (TCP_SEQ_LT (Right, Tcb->SndWl2 + Tcb->SndWnd)) { | |
if ((Tcb->SndWl1 == Seg->Seq) && | |
(Tcb->SndWl2 == Seg->Ack) && | |
(Len == 0)) { | |
goto NO_UPDATE; | |
} | |
DEBUG ((EFI_D_WARN, "TcpInput: peer shrinks the" | |
" window for connected TCB %p\n", Tcb)); | |
if ((Tcb->CongestState == TCP_CONGEST_RECOVER) && | |
(TCP_SEQ_LT (Right, Tcb->Recover))) { | |
Tcb->Recover = Right; | |
} | |
if ((Tcb->CongestState == TCP_CONGEST_LOSS) && | |
(TCP_SEQ_LT (Right, Tcb->LossRecover))) { | |
Tcb->LossRecover = Right; | |
} | |
if (TCP_SEQ_LT (Right, Tcb->SndNxt)) { | |
Tcb->SndNxt = Right; | |
if (Right == Tcb->SndUna) { | |
TcpClearTimer (Tcb, TCP_TIMER_REXMIT); | |
TcpSetProbeTimer (Tcb); | |
} | |
} | |
} | |
Tcb->SndWnd = Seg->Wnd; | |
Tcb->SndWndMax = MAX (Tcb->SndWnd, Tcb->SndWndMax); | |
Tcb->SndWl1 = Seg->Seq; | |
Tcb->SndWl2 = Seg->Ack; | |
} | |
NO_UPDATE: | |
if (TCP_FLG_ON (Tcb->CtrlFlag, TCP_CTRL_FIN_SENT) && | |
(Tcb->SndUna == Tcb->SndNxt)) { | |
DEBUG ((EFI_D_INFO, "TcpInput: local FIN is ACKed by" | |
" peer for connected TCB %p\n", Tcb)); | |
TCP_SET_FLG (Tcb->CtrlFlag, TCP_CTRL_FIN_ACKED); | |
} | |
// | |
// Transit the state if proper. | |
// | |
switch (Tcb->State) { | |
case TCP_FIN_WAIT_1: | |
if (TCP_FLG_ON (Tcb->CtrlFlag, TCP_CTRL_FIN_ACKED)) { | |
TcpSetState (Tcb, TCP_FIN_WAIT_2); | |
TcpClearAllTimer (Tcb); | |
TcpSetTimer (Tcb, TCP_TIMER_FINWAIT2, Tcb->FinWait2Timeout); | |
} | |
case TCP_FIN_WAIT_2: | |
break; | |
case TCP_CLOSE_WAIT: | |
break; | |
case TCP_CLOSING: | |
if (TCP_FLG_ON (Tcb->CtrlFlag, TCP_CTRL_FIN_ACKED)) { | |
TcpSetState (Tcb, TCP_TIME_WAIT); | |
TcpClearAllTimer (Tcb); | |
if (Tcb->TimeWaitTimeout != 0) { | |
TcpSetTimer (Tcb, TCP_TIMER_2MSL, Tcb->TimeWaitTimeout); | |
} else { | |
DEBUG ((EFI_D_WARN, "Connection closed immediately " | |
"because app disables TIME_WAIT timer for %p\n", Tcb)); | |
TcpClose (Tcb); | |
} | |
} | |
break; | |
case TCP_LAST_ACK: | |
if (TCP_FLG_ON (Tcb->CtrlFlag, TCP_CTRL_FIN_ACKED)) { | |
TcpSetState (Tcb, TCP_CLOSED); | |
} | |
break; | |
case TCP_TIME_WAIT: | |
TcpSendAck (Tcb); | |
if (Tcb->TimeWaitTimeout != 0) { | |
TcpSetTimer (Tcb, TCP_TIMER_2MSL, Tcb->TimeWaitTimeout); | |
} else { | |
DEBUG ((EFI_D_WARN, "Connection closed immediately " | |
"because app disables TIME_WAIT timer for %p\n", Tcb)); | |
TcpClose (Tcb); | |
} | |
break; | |
default: | |
break; | |
} | |
// | |
// Sixth step: Check the URG bit.update the Urg point | |
// if in TCP_CAN_RECV, otherwise, leave the RcvUp intact. | |
// | |
StepSix: | |
Tcb->Idle = 0; | |
TcpSetKeepaliveTimer (Tcb); | |
if (TCP_FLG_ON (Seg->Flag, TCP_FLG_URG) && | |
!TCP_FIN_RCVD (Tcb->State)) { | |
DEBUG ((EFI_D_INFO, "TcpInput: received urgent data " | |
"from peer for connected TCB %p\n", Tcb)); | |
Urg = Seg->Seq + Seg->Urg; | |
if (TCP_FLG_ON (Tcb->CtrlFlag, TCP_CTRL_RCVD_URG) && | |
TCP_SEQ_GT (Urg, Tcb->RcvUp)) { | |
Tcb->RcvUp = Urg; | |
} else { | |
Tcb->RcvUp = Urg; | |
TCP_SET_FLG (Tcb->CtrlFlag, TCP_CTRL_RCVD_URG); | |
} | |
} | |
// | |
// Seventh step: Process the segment data | |
// | |
if (Seg->End != Seg->Seq) { | |
if (TCP_FIN_RCVD (Tcb->State)) { | |
DEBUG ((EFI_D_WARN, "TcpInput: connection reset because" | |
" data is lost for connected TCB %p\n", Tcb)); | |
goto RESET_THEN_DROP; | |
} | |
if (TCP_LOCAL_CLOSED (Tcb->State) && (Nbuf->TotalSize != 0)) { | |
DEBUG ((EFI_D_WARN, "TcpInput: connection reset because" | |
" data is lost for connected TCB %p\n", Tcb)); | |
goto RESET_THEN_DROP; | |
} | |
TcpQueueData (Tcb, Nbuf); | |
if (TcpDeliverData (Tcb) == -1) { | |
goto RESET_THEN_DROP; | |
} | |
if (!IsListEmpty (&Tcb->RcvQue)) { | |
TCP_SET_FLG (Tcb->CtrlFlag, TCP_CTRL_ACK_NOW); | |
} | |
} | |
// | |
// Eighth step: check the FIN. | |
// This step is moved to TcpDeliverData. FIN will be | |
// processed in sequence there. Check the comments in | |
// the beginning of the file header for information. | |
// | |
// | |
// Tcb is a new child of the listening Parent, | |
// commit it. | |
// | |
if (Parent != NULL) { | |
Tcb->Parent = Parent; | |
TcpInsertTcb (Tcb); | |
} | |
if ((Tcb->State != TCP_CLOSED) && | |
(TcpToSendData (Tcb, 0) == 0) && | |
(TCP_FLG_ON (Tcb->CtrlFlag, TCP_CTRL_ACK_NOW) || (Nbuf->TotalSize != 0))) { | |
TcpToSendAck (Tcb); | |
} | |
NetbufFree (Nbuf); | |
return 0; | |
RESET_THEN_DROP: | |
TcpSendReset (Tcb, Head, Len, Dst, Src); | |
DROP_CONNECTION: | |
ASSERT ((Tcb != NULL) && (Tcb->Sk != NULL)); | |
NetbufFree (Nbuf); | |
TcpClose (Tcb); | |
return -1; | |
SEND_RESET: | |
TcpSendReset (Tcb, Head, Len, Dst, Src); | |
DISCARD: | |
// | |
// Tcb is a child of Parent, and it doesn't survive | |
// | |
DEBUG ((EFI_D_WARN, "Tcp4Input: Discard a packet\n")); | |
NetbufFree (Nbuf); | |
if ((Parent != NULL) && (Tcb != NULL)) { | |
ASSERT (Tcb->Sk != NULL); | |
TcpClose (Tcb); | |
} | |
return 0; | |
} | |
/** | |
Process the received ICMP error messages for TCP. | |
@param Nbuf Buffer that contains part of the TCP segment without IP header | |
truncated from the ICMP error packet. | |
@param IcmpErr The ICMP error code interpreted from ICMP error packet. | |
@param Src Source address of the ICMP error message. | |
@param Dst Destination address of the ICMP error message. | |
**/ | |
VOID | |
TcpIcmpInput ( | |
IN NET_BUF *Nbuf, | |
IN ICMP_ERROR IcmpErr, | |
IN UINT32 Src, | |
IN UINT32 Dst | |
) | |
{ | |
TCP_HEAD *Head; | |
TCP_CB *Tcb; | |
TCP_SEQNO Seq; | |
EFI_STATUS IcmpErrStatus; | |
BOOLEAN IcmpErrIsHard; | |
BOOLEAN IcmpErrNotify; | |
Head = (TCP_HEAD *) NetbufGetByte (Nbuf, 0, NULL); | |
Tcb = TcpLocateTcb ( | |
Head->DstPort, | |
Dst, | |
Head->SrcPort, | |
Src, | |
FALSE | |
); | |
if (Tcb == NULL || Tcb->State == TCP_CLOSED) { | |
goto CLEAN_EXIT; | |
} | |
// | |
// Validate the sequence number. | |
// | |
Seq = NTOHL (Head->Seq); | |
if (!(TCP_SEQ_LEQ (Tcb->SndUna, Seq) && TCP_SEQ_LT (Seq, Tcb->SndNxt))) { | |
goto CLEAN_EXIT; | |
} | |
IcmpErrStatus = IpIoGetIcmpErrStatus (IcmpErr, &IcmpErrIsHard, &IcmpErrNotify); | |
if (IcmpErrNotify) { | |
SOCK_ERROR (Tcb->Sk, IcmpErrStatus); | |
} | |
if (IcmpErrIsHard) { | |
TcpClose (Tcb); | |
} | |
CLEAN_EXIT: | |
NetbufFree (Nbuf); | |
} |