Hesham/wintun
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Don't discard unfitting NBLs and fix prepend ref counting

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Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
This commit is contained in:
Jason A. Donenfeld 2019-03-28 08:30:13 +01:00
parent 9294d4b498
commit 64c408a2e4
1 changed files with 24 additions and 7 deletions
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31
wintun.c
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@ -300,6 +300,12 @@ static NTSTATUS TunGetIRPBuffer(_Inout_ IRP *Irp, _Out_ UCHAR **buffer, _Out_ UL
return STATUS_SUCCESS; return STATUS_SUCCESS;
} }
_IRQL_requires_max_(DISPATCH_LEVEL)
static BOOLEAN TunCanFitIntoIrp(_Inout_ IRP *Irp, _In_ NET_BUFFER *nb)
{
return TRUE; //TODO(rozmansi): Implement me!
}
_IRQL_requires_max_(DISPATCH_LEVEL) _IRQL_requires_max_(DISPATCH_LEVEL)
static NTSTATUS TunWriteIntoIrp(_Inout_ IRP *Irp, _In_ NET_BUFFER *nb) static NTSTATUS TunWriteIntoIrp(_Inout_ IRP *Irp, _In_ NET_BUFFER *nb)
{ {
@ -432,18 +438,19 @@ static NET_BUFFER *TunQueueRemove(_Inout_ TUN_CTX *ctx, _Out_ NET_BUFFER_LIST **
/* Note: Must be called immediately after TunQueueRemove without dropping ctx->PacketQueue.Lock. */ /* Note: Must be called immediately after TunQueueRemove without dropping ctx->PacketQueue.Lock. */
_Requires_lock_held_(ctx->PacketQueue.Lock) _Requires_lock_held_(ctx->PacketQueue.Lock)
_IRQL_requires_(DISPATCH_LEVEL) _IRQL_requires_(DISPATCH_LEVEL)
static void TunQueuePrepend(_Inout_ TUN_CTX *ctx, _In_ NET_BUFFER *nb, _In_ NET_BUFFER_LIST *nbl_detached) static void TunQueuePrepend(_Inout_ TUN_CTX *ctx, _In_ NET_BUFFER *nb, _In_ NET_BUFFER_LIST *nbl)
{ {
ctx->PacketQueue.NextNb = nb; ctx->PacketQueue.NextNb = nb;
if (!nbl_detached) if (!nbl || nbl == ctx->PacketQueue.FirstNbl)
return; return;
TunNBLRefInc(nbl);
if (!ctx->PacketQueue.FirstNbl) if (!ctx->PacketQueue.FirstNbl)
ctx->PacketQueue.FirstNbl = ctx->PacketQueue.LastNbl = nbl_detached; ctx->PacketQueue.FirstNbl = ctx->PacketQueue.LastNbl = nbl;
else { else {
NET_BUFFER_LIST_NEXT_NBL(nbl_detached) = ctx->PacketQueue.FirstNbl; NET_BUFFER_LIST_NEXT_NBL(nbl) = ctx->PacketQueue.FirstNbl;
ctx->PacketQueue.FirstNbl = nbl_detached; ctx->PacketQueue.FirstNbl = nbl;
} }
} }
@ -468,13 +475,23 @@ static void TunQueueProcess(_Inout_ TUN_CTX *ctx)
} }
irp = IoCsqRemoveNextIrp(&ctx->Device.ReadQueue.Csq, NULL); irp = IoCsqRemoveNextIrp(&ctx->Device.ReadQueue.Csq, NULL);
if (!irp) { if (!irp) {
if (!nbl|| !TunNBLRefDec(ctx, nbl, NDIS_SEND_COMPLETE_FLAGS_DISPATCH_LEVEL)) TunQueuePrepend(ctx, nb, nbl);
TunQueuePrepend(ctx, nb, nbl);
KeReleaseInStackQueuedSpinLock(&lqh); KeReleaseInStackQueuedSpinLock(&lqh);
if (nbl)
TunNBLRefDec(ctx, nbl, 0);
return; return;
} }
} else } else
nb = TunQueueRemove(ctx, &nbl); nb = TunQueueRemove(ctx, &nbl);
if (!TunCanFitIntoIrp(irp, nb)) {
TunQueuePrepend(ctx, nb, nbl);
if (nbl)
TunNBLRefDec(ctx, nbl, NDIS_SEND_COMPLETE_FLAGS_DISPATCH_LEVEL);
nbl = NULL;
nb = NULL;
}
KeReleaseInStackQueuedSpinLock(&lqh); KeReleaseInStackQueuedSpinLock(&lqh);
if (!nb || (status = TunWriteIntoIrp(irp, nb)) == STATUS_BUFFER_TOO_SMALL) { /* irp complete */ if (!nb || (status = TunWriteIntoIrp(irp, nb)) == STATUS_BUFFER_TOO_SMALL) { /* irp complete */