snow/wireguard-go
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wintun: don't retry when not creating

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The only time we're trying to counteract the race condition is when
we're creating a driver. When we're simply looking up all drivers, it
doesn't make sense to retry.
This commit is contained in:
Jason A. Donenfeld 2019-05-02 23:53:15 +02:00
parent 247e14693a
commit 46dbf54040
2 changed files with 26 additions and 9 deletions
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6
tun/wintun/registryhacks_windows.go
View file

@ -11,7 +11,7 @@ import (
) )
const ( const (
numRetries = 100 numRetries = 100
retryTimeout = 150 * time.Millisecond retryTimeout = 150 * time.Millisecond
) )
@ -21,7 +21,7 @@ func registryOpenKeyRetry(k registry.Key, path string, access uint32) (key regis
if err == nil { if err == nil {
break break
} }
if i != numRetries - 1 { if i != numRetries-1 {
time.Sleep(retryTimeout) time.Sleep(retryTimeout)
} }
} }
@ -34,7 +34,7 @@ func keyGetStringValueRetry(k registry.Key, name string) (val string, valtype ui
if err == nil { if err == nil {
break break
} }
if i != numRetries - 1 { if i != numRetries-1 {
time.Sleep(retryTimeout) time.Sleep(retryTimeout)
} }
} }

29
tun/wintun/wintun_windows.go
View file

@ -38,7 +38,7 @@ const machineName = ""
// //
// MakeWintun creates interface handle and populates it from device registry key // MakeWintun creates interface handle and populates it from device registry key
// //
func MakeWintun(deviceInfoSet setupapi.DevInfo, deviceInfoData *setupapi.DevInfoData) (*Wintun, error) { func makeWintun(deviceInfoSet setupapi.DevInfo, deviceInfoData *setupapi.DevInfoData, wait bool) (*Wintun, error) {
// Open HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class\<class>\<id> registry key. // Open HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class\<class>\<id> registry key.
key, err := deviceInfoSet.OpenDevRegKey(deviceInfoData, setupapi.DICS_FLAG_GLOBAL, 0, setupapi.DIREG_DRV, registry.READ) key, err := deviceInfoSet.OpenDevRegKey(deviceInfoData, setupapi.DICS_FLAG_GLOBAL, 0, setupapi.DIREG_DRV, registry.READ)
if err != nil { if err != nil {
@ -50,7 +50,11 @@ func MakeWintun(deviceInfoSet setupapi.DevInfo, deviceInfoData *setupapi.DevInfo
var valueType uint32 var valueType uint32
// Read the NetCfgInstanceId value. // Read the NetCfgInstanceId value.
valueStr, valueType, err = keyGetStringValueRetry(key, "NetCfgInstanceId") if wait {
valueStr, valueType, err = keyGetStringValueRetry(key, "NetCfgInstanceId")
} else {
valueStr, valueType, err = key.GetStringValue("NetCfgInstanceId")
}
if err != nil { if err != nil {
return nil, errors.New("RegQueryStringValue(\"NetCfgInstanceId\") failed: " + err.Error()) return nil, errors.New("RegQueryStringValue(\"NetCfgInstanceId\") failed: " + err.Error())
} }
@ -121,13 +125,14 @@ func GetInterface(ifname string, hwndParent uintptr) (*Wintun, error) {
} }
// Get interface ID. // Get interface ID.
wintun, err := MakeWintun(devInfoList, deviceData) wintun, err := makeWintun(devInfoList, deviceData, false)
if err != nil { if err != nil {
continue continue
} }
//TODO: is there a better way than comparing ifnames?
// Get interface name. // Get interface name.
ifname2, err := wintun.GetInterfaceName() ifname2, err := wintun.getInterfaceNameNoRetry()
if err != nil { if err != nil {
continue continue
} }
@ -301,7 +306,7 @@ func CreateInterface(description string, hwndParent uintptr) (*Wintun, bool, err
// installation continues in the background. It might take a while, before all registry // installation continues in the background. It might take a while, before all registry
// keys and values are populated. // keys and values are populated.
for numAttempts := 0; numAttempts < 30; numAttempts++ { for numAttempts := 0; numAttempts < 30; numAttempts++ {
wintun, err = MakeWintun(devInfoList, deviceData) wintun, err = makeWintun(devInfoList, deviceData, true)
if err != nil { if err != nil {
if errWin, ok := err.(syscall.Errno); ok && errWin == windows.ERROR_FILE_NOT_FOUND { if errWin, ok := err.(syscall.Errno); ok && errWin == windows.ERROR_FILE_NOT_FOUND {
// Wait and retry. TODO: Wait for a cancellable event instead. // Wait and retry. TODO: Wait for a cancellable event instead.
@ -371,7 +376,8 @@ func (wintun *Wintun) DeleteInterface(hwndParent uintptr) (bool, bool, error) {
} }
// Get interface ID. // Get interface ID.
wintun2, err := MakeWintun(devInfoList, deviceData) //TODO: Store some ID in the Wintun object such that this call isn't required.
wintun2, err := makeWintun(devInfoList, deviceData, false)
if err != nil { if err != nil {
continue continue
} }
@ -446,6 +452,17 @@ func (wintun *Wintun) GetInterfaceName() (string, error) {
return getRegStringValue(key, "Name") return getRegStringValue(key, "Name")
} }
func (wintun *Wintun) getInterfaceNameNoRetry() (string, error) {
key, err := registry.OpenKey(registry.LOCAL_MACHINE, wintun.GetNetRegKeyName(), registry.QUERY_VALUE)
if err != nil {
return "", errors.New("Network-specific registry key open failed: " + err.Error())
}
defer key.Close()
// Get the interface name.
return getRegStringValue(key, "Name")
}
// //
// SetInterfaceName sets network interface name. // SetInterfaceName sets network interface name.
// //