[PATCH v2 1/2] NetworkPkg/TcpDxe: Add wnd scale check before shrinking window

[PATCH v2 1/2] NetworkPkg/TcpDxe: Add wnd scale check before shrinking window

[atepin]

Moving Right window edge to the left on sender side without additional
check can lead to the TCP deadlock, when receiver ACKs proper segment,
while sender discards it for future ACK. To prevent this add check if
usable window (or shrink amount in this case) is bigger then receiver's
window scale factor.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Andrey Tepin <atepin@kraftway.ru>
---
 NetworkPkg/TcpDxe/TcpInput.c | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/NetworkPkg/TcpDxe/TcpInput.c b/NetworkPkg/TcpDxe/TcpInput.c
index 04c8a82..74ea02b 100644
--- a/NetworkPkg/TcpDxe/TcpInput.c
+++ b/NetworkPkg/TcpDxe/TcpInput.c
@@ -1306,8 +1306,21 @@ TcpInput (
       }
 
       if (TCP_SEQ_LT (Right, Tcb->SndNxt)) {
+        DEBUG (
+          (EFI_D_WARN,
+          "TcpInput: peer advise negative useable window for connected TCB %p\n",
+          Tcb)
+          );
 
-        Tcb->SndNxt = Right;
+        INT32 Usable = 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) {
 
-- 
2.7.4

[PATCH v2 0/2] Add wnd scale check before shrinking window

[atepin]

This is an updated patch. Previous patch can be found in thread named
"Fix unconditional window shrinking" here:
https://lists.01.org/pipermail/edk2-devel/2017-March/009129.html

Andrey Tepin (2):
  NetworkPkg/TcpDxe: Add wnd scale check before shrinking window
  MdeModulePkg/Tcp4Dxe: Add wnd scale check before shrinking window

 MdeModulePkg/Universal/Network/Tcp4Dxe/Tcp4Input.c | 15 ++++++++++++++-
 NetworkPkg/TcpDxe/TcpInput.c                       | 15 ++++++++++++++-
 2 files changed, 28 insertions(+), 2 deletions(-)

-- 
2.7.4

[PATCH v2 2/2] MdeModulePkg/Tcp4Dxe: Add wnd scale check before shrinking window

[atepin]

Moving Right window edge to the left on sender side without additional
check can lead to the TCP deadlock, when receiver ACKs proper segment,
while sender discards it for future ACK. To prevent this add check if
usable window (or shrink amount in this case) is bigger then receiver's
window scale factor.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Andrey Tepin <atepin@kraftway.ru>
---
 MdeModulePkg/Universal/Network/Tcp4Dxe/Tcp4Input.c | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/MdeModulePkg/Universal/Network/Tcp4Dxe/Tcp4Input.c b/MdeModulePkg/Universal/Network/Tcp4Dxe/Tcp4Input.c
index 1000538..77110d8 100644
--- a/MdeModulePkg/Universal/Network/Tcp4Dxe/Tcp4Input.c
+++ b/MdeModulePkg/Universal/Network/Tcp4Dxe/Tcp4Input.c
@@ -1187,8 +1187,21 @@ TcpInput (
       }
 
       if (TCP_SEQ_LT (Right, Tcb->SndNxt)) {
+        DEBUG (
+          (EFI_D_WARN,
+          "TcpInput: peer advise negative useable window for connected TCB %p\n",
+          Tcb)
+          );
 
-        Tcb->SndNxt = Right;
+        INT32 Usable = 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) {
 
-- 
2.7.4

Re: [PATCH v2 0/2] Add wnd scale check before shrinking window

[atepin]

I'm adding recipients from previous thread.

Regards,
Andrey

On 20.04.2017 12:30, Тёпин Андрей Сергеевич wrote:
> This is an updated patch. Previous patch can be found in thread named
> "Fix unconditional window shrinking" here:
> https://lists.01.org/pipermail/edk2-devel/2017-March/009129.html
>
> Andrey Tepin (2):
>    NetworkPkg/TcpDxe: Add wnd scale check before shrinking window
>    MdeModulePkg/Tcp4Dxe: Add wnd scale check before shrinking window
>
>   MdeModulePkg/Universal/Network/Tcp4Dxe/Tcp4Input.c | 15 ++++++++++++++-
>   NetworkPkg/TcpDxe/TcpInput.c                       | 15 ++++++++++++++-
>   2 files changed, 28 insertions(+), 2 deletions(-)
>

Re: [PATCH v2 0/2] Add wnd scale check before shrinking window

[Fu, Siyuan]

Reviewed-by: Fu Siyuan <siyuan.fu@intel.com>

-----Original Message-----
From: edk2-devel [mailto:edk2-devel-bounces@lists.01.org] On Behalf Of atepin@kraftway.ru
Sent: 2017年4月20日 17:31
To: edk2-devel@lists.01.org
Subject: [edk2] [PATCH v2 0/2] Add wnd scale check before shrinking window

This is an updated patch. Previous patch can be found in thread named "Fix unconditional window shrinking" here:
https://lists.01.org/pipermail/edk2-devel/2017-March/009129.html

Andrey Tepin (2):
  NetworkPkg/TcpDxe: Add wnd scale check before shrinking window
  MdeModulePkg/Tcp4Dxe: Add wnd scale check before shrinking window

 MdeModulePkg/Universal/Network/Tcp4Dxe/Tcp4Input.c | 15 ++++++++++++++-
 NetworkPkg/TcpDxe/TcpInput.c                       | 15 ++++++++++++++-
 2 files changed, 28 insertions(+), 2 deletions(-)

--
2.7.4
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