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/* SPDX-License-Identifier: MIT
*
* Copyright (C) 2019 WireGuard LLC. All Rights Reserved.
*/
package winipcfg
import (
"sync"
"golang.org/x/sys/windows"
)
// RouteChangeCallback structure allows route change callback handling.
type RouteChangeCallback struct {
cb func(notificationType MibNotificationType, route *MibIPforwardRow2)
}
var (
routeChangeAddRemoveMutex = sync.Mutex{}
routeChangeMutex = sync.Mutex{}
routeChangeCallbacks = make(map[*RouteChangeCallback]bool)
routeChangeHandle = windows.Handle(0)
)
// RegisterRouteChangeCallback registers a new RouteChangeCallback. If this particular callback is already
// registered, the function will silently return. Returned RouteChangeCallback.Unregister method should be used
// to unregister.
func RegisterRouteChangeCallback(callback func(notificationType MibNotificationType, route *MibIPforwardRow2)) (*RouteChangeCallback, error) {
s := &RouteChangeCallback{callback}
routeChangeAddRemoveMutex.Lock()
defer routeChangeAddRemoveMutex.Unlock()
routeChangeMutex.Lock()
defer routeChangeMutex.Unlock()
routeChangeCallbacks[s] = true
if routeChangeHandle == 0 {
err := notifyRouteChange2(windows.AF_UNSPEC, windows.NewCallback(routeChanged), 0, false, &routeChangeHandle)
if err != nil {
delete(routeChangeCallbacks, s)
routeChangeHandle = 0
return nil, err
}
}
return s, nil
}
// Unregister unregisters the callback.
func (callback *RouteChangeCallback) Unregister() error {
routeChangeAddRemoveMutex.Lock()
defer routeChangeAddRemoveMutex.Unlock()
routeChangeMutex.Lock()
delete(routeChangeCallbacks, callback)
removeIt := len(routeChangeCallbacks) == 0 && routeChangeHandle != 0
routeChangeMutex.Unlock()
if removeIt {
err := cancelMibChangeNotify2(routeChangeHandle)
if err != nil {
return err
}
routeChangeHandle = 0
}
return nil
}
func routeChanged(callerContext uintptr, row *MibIPforwardRow2, notificationType MibNotificationType) uintptr {
routeChangeMutex.Lock()
for cb := range routeChangeCallbacks {
cb.cb(notificationType, row)
}
routeChangeMutex.Unlock()
return 0
}
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