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wintun: manage ring memory manually

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It's large and Go's garbage collector doesn't deal with it especially
well.
This commit is contained in:
Jason A. Donenfeld 2019-11-21 14:48:21 +01:00
parent 4cdf805b29
commit 2b242f9393
2 changed files with 27 additions and 7 deletions
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6
tun/tun_windows.go
View file

@ -35,11 +35,11 @@ type NativeTun struct {
wt *wintun.Interface
handle windows.Handle
close bool
rings wintun.RingDescriptor
events chan Event
errors chan error
forcedMTU int
rate rateJuggler
rings *wintun.RingDescriptor
}
const WintunPool = wintun.Pool("WireGuard")
@ -93,13 +93,13 @@ func CreateTUNWithRequestedGUID(ifname string, requestedGUID *windows.GUID, mtu
forcedMTU: forcedMTU,
}
err = tun.rings.Init()
tun.rings, err = wintun.NewRingDescriptor()
if err != nil {
tun.Close()
return nil, fmt.Errorf("Error creating events: %v", err)
}
tun.handle, err = tun.wt.Register(&tun.rings)
tun.handle, err = tun.wt.Register(tun.rings)
if err != nil {
tun.Close()
return nil, fmt.Errorf("Error registering rings: %v", err)

28
tun/wintun/ring_windows.go
View file

@ -6,6 +6,7 @@
package wintun
import (
"runtime"
"unsafe"
"golang.org/x/sys/windows"
@ -53,25 +54,44 @@ func PacketAlign(size uint32) uint32 {
return (size + (PacketAlignment - 1)) &^ (PacketAlignment - 1)
}
func (descriptor *RingDescriptor) Init() (err error) {
func NewRingDescriptor() (descriptor *RingDescriptor, err error) {
descriptor = new(RingDescriptor)
allocatedRegion, err := windows.VirtualAlloc(0, unsafe.Sizeof(Ring{})*2, windows.MEM_COMMIT|windows.MEM_RESERVE, windows.PAGE_READWRITE)
if err != nil {
return
}
defer func() {
if err != nil {
descriptor.free()
descriptor = nil
}
}()
descriptor.Send.Size = uint32(unsafe.Sizeof(Ring{}))
descriptor.Send.Ring = &Ring{}
descriptor.Send.Ring = (*Ring)(unsafe.Pointer(allocatedRegion))
descriptor.Send.TailMoved, err = windows.CreateEvent(nil, 0, 0, nil)
if err != nil {
return
}
descriptor.Receive.Size = uint32(unsafe.Sizeof(Ring{}))
descriptor.Receive.Ring = &Ring{}
descriptor.Receive.Ring = (*Ring)(unsafe.Pointer(allocatedRegion + unsafe.Sizeof(Ring{})))
descriptor.Receive.TailMoved, err = windows.CreateEvent(nil, 0, 0, nil)
if err != nil {
windows.CloseHandle(descriptor.Send.TailMoved)
return
}
runtime.SetFinalizer(descriptor, func(d *RingDescriptor) { d.free() })
return
}
func (descriptor *RingDescriptor) free() {
if descriptor.Send.Ring != nil {
windows.VirtualFree(uintptr(unsafe.Pointer(descriptor.Send.Ring)), 0, windows.MEM_RELEASE)
descriptor.Send.Ring = nil
descriptor.Receive.Ring = nil
}
}
func (descriptor *RingDescriptor) Close() {
if descriptor.Send.TailMoved != 0 {
windows.CloseHandle(descriptor.Send.TailMoved)