From: "Tian, Feng" <feng.tian@intel.com>
To: "atepin@kraftway.ru" <atepin@kraftway.ru>,
"edk2-devel@lists.01.org" <edk2-devel@lists.01.org>,
"Ye, Ting" <ting.ye@intel.com>,
"Fu, Siyuan" <siyuan.fu@intel.com>,
"Wu, Jiaxin" <jiaxin.wu@intel.com>
Cc: "Tian, Feng" <feng.tian@intel.com>
Subject: Re: [PATCH 1/2] MdeModulePkg/Tcp4Dxe: Fix unconditional window shrinking
Date: Wed, 29 Mar 2017 06:56:35 +0000 [thread overview]
Message-ID: <7F1BAD85ADEA444D97065A60D2E97EE5699CFDB6@SHSMSX101.ccr.corp.intel.com> (raw)
In-Reply-To: <de1fbe46a5db36715da70c9823f2ee85e65b8ae2.1490617399.git.atepin@kraftway.ru>
Adding network module owners for further review.
Thanks
Feng
-----Original Message-----
From: edk2-devel [mailto:edk2-devel-bounces@lists.01.org] On Behalf Of atepin@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 <atepin@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
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prev parent reply other threads:[~2017-03-29 6:57 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-03-28 7:20 [PATCH 1/2] MdeModulePkg/Tcp4Dxe: Fix unconditional window shrinking atepin
2017-03-28 7:20 ` [PATCH 2/2] NetworkPkg/TcpDxe: " atepin
2017-04-05 9:47 ` Fu, Siyuan
2017-04-06 15:34 ` atepin
2017-04-12 10:48 ` Fu, Siyuan
2017-04-13 14:33 ` atepin
2017-04-14 1:03 ` Fu, Siyuan
2017-04-14 9:00 ` Fu, Siyuan
2017-04-14 13:31 ` atepin
2017-04-17 2:41 ` Fu, Siyuan
2017-04-17 14:40 ` atepin
2017-04-18 3:55 ` Fu, Siyuan
2017-04-18 8:06 ` atepin
2017-04-18 8:46 ` Fu, Siyuan
2017-04-18 9:57 ` atepin
2017-03-29 6:56 ` Tian, Feng [this message]
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