Adding network module owners for further review. Thanks Feng
-----Original Message----- From: edk2-devel [mailto:edk2-devel-boun...@lists.01.org] On Behalf Of ate...@kraftway.ru Sent: Tuesday, March 28, 2017 3:20 PM To: edk2-devel@lists.01.org Subject: [edk2] [PATCH 1/2] MdeModulePkg/Tcp4Dxe: Fix unconditional window shrinking Moving Right window edge to the left on sender side without additional checks leads to the situation when sender assumes the receiver shrunk its rcv buffer, when, in fact, it only reduced window size. This is a TCP deadlock situation. Receiver ACKs proper segment, while sender discards it for future ACK. Add check for negative usable window to prevent erroneous window shrinking. Contributed-under: TianoCore Contribution Agreement 1.0 Signed-off-by: Andrey Tepin <ate...@kraftway.ru> --- MdeModulePkg/Universal/Network/Tcp4Dxe/Tcp4Input.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/MdeModulePkg/Universal/Network/Tcp4Dxe/Tcp4Input.c b/MdeModulePkg/Universal/Network/Tcp4Dxe/Tcp4Input.c index 1000538..ea0766a 100644 --- a/MdeModulePkg/Universal/Network/Tcp4Dxe/Tcp4Input.c +++ b/MdeModulePkg/Universal/Network/Tcp4Dxe/Tcp4Input.c @@ -703,6 +703,7 @@ TcpInput ( TCP_SEG *Seg; TCP_SEQNO Right; TCP_SEQNO Urg; + INT32 UsableWnd; NET_CHECK_SIGNATURE (Nbuf, NET_BUF_SIGNATURE); @@ -1188,7 +1189,10 @@ TcpInput ( if (TCP_SEQ_LT (Right, Tcb->SndNxt)) { - Tcb->SndNxt = Right; + UsableWnd = Tcb->SndUna + Tcb->SndWnd - Tcb->SndNxt; + if (UsableWnd < 0) { + Tcb->SndNxt = Right; + } if (Right == Tcb->SndUna) { -- 1.9.1 _______________________________________________ edk2-devel mailing list edk2-devel@lists.01.org https://lists.01.org/mailman/listinfo/edk2-devel _______________________________________________ edk2-devel mailing list edk2-devel@lists.01.org https://lists.01.org/mailman/listinfo/edk2-devel
