[PATCH 0/1] wintun driver get stalled for few sec until another packet is being sent -- approach 1

[PATCH 0/1] wintun driver get stalled for few sec until another packet is being sent -- approach 1

[odedkatz]

## changes:
- I observed a code [which can lead to a stall condition in the wintun driver](https://github.com/Twingate/wintun/blob/6bfc34a60aa944149fdc7e9cddb191e9a8b6ec1a/driver/twintun.c#L487-L488)
- I didn't want to change the driver code as, I was not sure if it will create a busy loop on kernel
- so instead I tackle this on the client-part of wintun

# issue description:
## Reproducing issue
- run iperf client on Client machine with the command `iperf3 -c 127.0.0.1.us.east.direct.vpn -t 300 -b0 -P1`
- once in a while we see intervals when no throughput goes to 0 and it takes about 4-5 sec to get out of this situation.
     
      

odedkatz (1):
  remove the condition on possibly stale variable
    (Session->Descriptor.Receive.Ring->Alertable)    for Setting
    TailMoved event

 api/session.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

-- 
2.43.0

[PATCH 1/1] remove the condition on possibly stale variable (Session->Descriptor.Receive.Ring->Alertable) for Setting TailMoved event

[odedkatz]

otherwise wintun driver just holds on the event until something wakes it up (see here)[https://github.com/Twingate/wintun/blob/6bfc34a60aa944149fdc7e9cddb191e9a8b6ec1a/driver/twintun.c#L487-L488]
---
 api/session.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/api/session.c b/api/session.c
index ab96c64..dcaeb25 100644
--- a/api/session.c
+++ b/api/session.c
@@ -302,8 +302,7 @@ WintunSendPacket(TUN_SESSION *Session, const BYTE *Packet)
     if (Session->Descriptor.Receive.Ring->Tail != Session->Receive.TailRelease)
     {
         WriteULongRelease(&Session->Descriptor.Receive.Ring->Tail, Session->Receive.TailRelease);
-        if (ReadAcquire(&Session->Descriptor.Receive.Ring->Alertable))
-            SetEvent(Session->Descriptor.Receive.TailMoved);
+        SetEvent(Session->Descriptor.Receive.TailMoved);
     }
     LeaveCriticalSection(&Session->Receive.Lock);
 }
-- 
2.43.0