/**
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;
}
/**
Timeout handler for TCP retransmission timer.
@param Tcb Pointer to the TCP_CB of this TCP instance.
**/
VOID
TcpRexmitTimeout (
IN OUT TCP_CB *Tcb
)
{
UINT32 FlightSize;
DEBUG ((EFI_D_WARN, "TcpRexmitTimeout: transmission "
"timeout for TCB %p\n", Tcb));
//
// Set the congestion window. FlightSize is the
// amount of data that has been sent but not
// yet ACKed.
//
FlightSize = TCP_SUB_SEQ (Tcb->SndNxt, Tcb->SndUna);
Tcb->Ssthresh = MAX ((UINT32) (2 * Tcb->SndMss), FlightSize / 2);
Tcb->CWnd = Tcb->SndMss;
Tcb->LossRecover = Tcb->SndNxt;
Tcb->LossTimes++;
if ((Tcb->LossTimes > Tcb->MaxRexmit) &&
!TCP_TIMER_ON (Tcb->EnabledTimer, TCP_TIMER_CONNECT)) {
DEBUG ((EFI_D_ERROR, "TcpRexmitTimeout: connection closed "
"because too many timeouts for TCB %p\n", Tcb));
if (EFI_ABORTED == Tcb->Sk->SockError) {
SOCK_ERROR (Tcb->Sk, EFI_TIMEOUT);
}
TcpClose (Tcb);
return ;
}
TcpBackoffRto (Tcb);
TcpRetransmit (Tcb, Tcb->SndUna);
TcpSetTimer (Tcb, TCP_TIMER_REXMIT, Tcb->Rto);
Tcb->CongestState = TCP_CONGEST_LOSS;
TCP_CLEAR_FLG (Tcb->CtrlFlag, TCP_CTRL_RTT_ON);
}
