diff options
Diffstat (limited to 'NetworkPkg/TcpDxe')
| -rw-r--r-- | NetworkPkg/TcpDxe/TcpInput.c | 27 |
1 files changed, 23 insertions, 4 deletions
diff --git a/NetworkPkg/TcpDxe/TcpInput.c b/NetworkPkg/TcpDxe/TcpInput.c index 04c8a8269e..f8845dca47 100644 --- a/NetworkPkg/TcpDxe/TcpInput.c +++ b/NetworkPkg/TcpDxe/TcpInput.c @@ -1,7 +1,7 @@ /** @file
TCP input process routines.
- Copyright (c) 2009 - 2016, Intel Corporation. All rights reserved.<BR>
+ Copyright (c) 2009 - 2017, 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
@@ -738,6 +738,7 @@ TcpInput ( TCP_SEQNO Right;
TCP_SEQNO Urg;
UINT16 Checksum;
+ INT32 Usable;
ASSERT ((Version == IP_VERSION_4) || (Version == IP_VERSION_6));
@@ -1306,9 +1307,27 @@ TcpInput ( }
if (TCP_SEQ_LT (Right, Tcb->SndNxt)) {
-
- Tcb->SndNxt = Right;
-
+ //
+ // Check for Window Retraction in RFC7923 section 2.4.
+ // The lower n bits of the peer's actual receive window is wiped out if TCP
+ // window scale is enabled, it will look like the peer is shrinking the window.
+ // Check whether the SndNxt is out of the advertised receive window by more than
+ // 2^Rcv.Wind.Shift before moving the SndNxt to the left.
+ //
+ DEBUG (
+ (EFI_D_WARN,
+ "TcpInput: peer advise negative useable window for connected TCB %p\n",
+ Tcb)
+ );
+ Usable = TCP_SUB_SEQ (Tcb->SndNxt, Right);
+ if ((Usable >> Tcb->SndWndScale) > 0) {
+ DEBUG (
+ (EFI_D_WARN,
+ "TcpInput: SndNxt is out of window by more than window scale for TCB %p\n",
+ Tcb)
+ );
+ Tcb->SndNxt = Right;
+ }
if (Right == Tcb->SndUna) {
TcpClearTimer (Tcb, TCP_TIMER_REXMIT);
|