driver: introduce new module for talking with kernel driver

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>

4 files changed, 155 insertions, 40 deletions

diff --git a/manager/interfacecleanup.go b/manager/interfacecleanup.go
index c270f4ab..32976b79 100644
--- a/manager/interfacecleanup.go
+++ b/manager/interfacecleanup.go
@@ -11,33 +11,66 @@ import (
 	"golang.org/x/sys/windows"
 	"golang.org/x/sys/windows/svc"
 	"golang.org/x/sys/windows/svc/mgr"
-	"golang.zx2c4.com/wireguard/tun/wintun"
-
 	"golang.zx2c4.com/wireguard/tun"
+	"golang.zx2c4.com/wireguard/tun/wintun"
+	"golang.zx2c4.com/wireguard/windows/conf"
+	"golang.zx2c4.com/wireguard/windows/driver"
 	"golang.zx2c4.com/wireguard/windows/services"
 )
 
-func cleanupStaleWintunInterfaces() {
+func cleanupStaleNetworkInterfaces() {
 	m, err := mgr.Connect()
 	if err != nil {
 		return
 	}
 	defer m.Disconnect()
 
-	tun.WintunPool.DeleteMatchingAdapters(func(wintun *wintun.Adapter) bool {
-		interfaceName, err := wintun.Name()
+	if conf.AdminBool("ExperimentalKernelDriver") {
+		driver.DefaultPool.DeleteMatchingAdapters(func(wintun *driver.Adapter) bool {
+			interfaceName, err := wintun.Name()
+			if err != nil {
+				log.Printf("Removing network adapter because determining interface name failed: %v", err)
+				return true
+			}
+			serviceName, err := services.ServiceNameOfTunnel(interfaceName)
+			if err != nil {
+				log.Printf("Removing network adapter ‘%s’ because determining tunnel service name failed: %v", interfaceName, err)
+				return true
+			}
+			service, err := m.OpenService(serviceName)
+			if err == windows.ERROR_SERVICE_DOES_NOT_EXIST {
+				log.Printf("Removing network adapter ‘%s’ because no service for it exists", interfaceName)
+				return true
+			} else if err != nil {
+				return false
+			}
+			defer service.Close()
+			status, err := service.Query()
+			if err != nil {
+				return false
+			}
+			if status.State == svc.Stopped {
+				log.Printf("Removing network adapter ‘%s’ because its service is stopped", interfaceName)
+				return true
+			}
+			return false
+		})
+	}
+
+	tun.WintunPool.DeleteMatchingAdapters(func(adapter *wintun.Adapter) bool {
+		interfaceName, err := adapter.Name()
 		if err != nil {
-			log.Printf("Removing Wintun interface because determining interface name failed: %v", err)
+			log.Printf("Removing network adapter because determining interface name failed: %v", err)
 			return true
 		}
 		serviceName, err := services.ServiceNameOfTunnel(interfaceName)
 		if err != nil {
-			log.Printf("Removing Wintun interface ‘%s’ because determining tunnel service name failed: %v", interfaceName, err)
+			log.Printf("Removing network adapter ‘%s’ because determining tunnel service name failed: %v", interfaceName, err)
 			return true
 		}
 		service, err := m.OpenService(serviceName)
 		if err == windows.ERROR_SERVICE_DOES_NOT_EXIST {
-			log.Printf("Removing Wintun interface ‘%s’ because no service for it exists", interfaceName)
+			log.Printf("Removing network adapter ‘%s’ because no service for it exists", interfaceName)
 			return true
 		} else if err != nil {
 			return false
@@ -48,7 +81,7 @@ func cleanupStaleWintunInterfaces() {
 			return false
 		}
 		if status.State == svc.Stopped {
-			log.Printf("Removing Wintun interface ‘%s’ because its service is stopped", interfaceName)
+			log.Printf("Removing network adapter ‘%s’ because its service is stopped", interfaceName)
 			return true
 		}
 		return false
diff --git a/manager/ipc_driver.go b/manager/ipc_driver.go
new file mode 100644
index 00000000..dae213de
--- /dev/null
+++ b/manager/ipc_driver.go
@@ -0,0 +1,59 @@
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright (C) 2019-2021 WireGuard LLC. All Rights Reserved.
+ */
+
+package manager
+
+import (
+	"sync"
+
+	"golang.zx2c4.com/wireguard/windows/driver"
+)
+
+type lockedDriverAdapter struct {
+	*driver.Adapter
+	sync.Mutex
+}
+
+var driverAdapters = make(map[string]*lockedDriverAdapter)
+var driverAdaptersLock sync.RWMutex
+
+func findDriverAdapter(tunnelName string) (*lockedDriverAdapter, error) {
+	driverAdaptersLock.RLock()
+	driverAdapter, ok := driverAdapters[tunnelName]
+	if ok {
+		driverAdapter.Lock()
+		driverAdaptersLock.RUnlock()
+		return driverAdapter, nil
+	}
+	driverAdaptersLock.RUnlock()
+	driverAdaptersLock.Lock()
+	defer driverAdaptersLock.Unlock()
+	driverAdapter, ok = driverAdapters[tunnelName]
+	if ok {
+		driverAdapter.Lock()
+		return driverAdapter, nil
+	}
+	driverAdapter = &lockedDriverAdapter{}
+	var err error
+	driverAdapter.Adapter, err = driver.DefaultPool.OpenAdapter(tunnelName)
+	if err != nil {
+		return nil, err
+	}
+	driverAdapters[tunnelName] = driverAdapter
+	driverAdapter.Lock()
+	return driverAdapter, nil
+}
+
+func releaseDriverAdapter(tunnelName string) {
+	driverAdaptersLock.Lock()
+	defer driverAdaptersLock.Unlock()
+	driverAdapter, ok := driverAdapters[tunnelName]
+	if !ok {
+		return
+	}
+	driverAdapter.Lock()
+	delete(driverAdapters, tunnelName)
+	driverAdapter.Unlock()
+}
diff --git a/manager/ipc_server.go b/manager/ipc_server.go
index 9a36e60f..b9b1eb8c 100644
--- a/manager/ipc_server.go
+++ b/manager/ipc_server.go
@@ -47,41 +47,64 @@ func (s *ManagerService) StoredConfig(tunnelName string) (*conf.Config, error) {
 }
 
 func (s *ManagerService) RuntimeConfig(tunnelName string) (*conf.Config, error) {
-	storedConfig, err := conf.LoadFromName(tunnelName)
-	if err != nil {
-		return nil, err
-	}
-	pipe, err := connectTunnelServicePipe(tunnelName)
-	if err != nil {
-		return nil, err
-	}
-	pipe.SetDeadline(time.Now().Add(time.Second * 2))
-	_, err = pipe.Write([]byte("get=1\n\n"))
-	if err == windows.ERROR_NO_DATA {
-		log.Println("IPC pipe closed unexpectedly, so reopening")
-		pipe.Unlock()
-		disconnectTunnelServicePipe(tunnelName)
-		pipe, err = connectTunnelServicePipe(tunnelName)
+	if conf.AdminBool("ExperimentalKernelDriver") {
+		storedConfig, err := conf.LoadFromName(tunnelName)
+		if err != nil {
+			return nil, err
+		}
+		driverAdapter, err := findDriverAdapter(tunnelName)
+		if err != nil {
+			return nil, err
+		}
+		runtimeConfig, err := driverAdapter.Configuration()
+		if err != nil {
+			driverAdapter.Unlock()
+			releaseDriverAdapter(tunnelName)
+			return nil, err
+		}
+		conf := conf.FromDriverConfiguration(runtimeConfig, storedConfig)
+		driverAdapter.Unlock()
+		if s.elevatedToken == 0 {
+			conf.Redact()
+		}
+		return conf, nil
+	} else {
+		storedConfig, err := conf.LoadFromName(tunnelName)
+		if err != nil {
+			return nil, err
+		}
+		pipe, err := connectTunnelServicePipe(tunnelName)
 		if err != nil {
 			return nil, err
 		}
 		pipe.SetDeadline(time.Now().Add(time.Second * 2))
 		_, err = pipe.Write([]byte("get=1\n\n"))
-	}
-	if err != nil {
+		if err == windows.ERROR_NO_DATA {
+			log.Println("IPC pipe closed unexpectedly, so reopening")
+			pipe.Unlock()
+			disconnectTunnelServicePipe(tunnelName)
+			pipe, err = connectTunnelServicePipe(tunnelName)
+			if err != nil {
+				return nil, err
+			}
+			pipe.SetDeadline(time.Now().Add(time.Second * 2))
+			_, err = pipe.Write([]byte("get=1\n\n"))
+		}
+		if err != nil {
+			pipe.Unlock()
+			disconnectTunnelServicePipe(tunnelName)
+			return nil, err
+		}
+		conf, err := conf.FromUAPI(pipe, storedConfig)
 		pipe.Unlock()
-		disconnectTunnelServicePipe(tunnelName)
-		return nil, err
-	}
-	conf, err := conf.FromUAPI(pipe, storedConfig)
-	pipe.Unlock()
-	if err != nil {
-		return nil, err
-	}
-	if s.elevatedToken == 0 {
-		conf.Redact()
+		if err != nil {
+			return nil, err
+		}
+		if s.elevatedToken == 0 {
+			conf.Redact()
+		}
+		return conf, nil
 	}
-	return conf, nil
 }
 
 func (s *ManagerService) Start(tunnelName string) error {
@@ -116,7 +139,7 @@ func (s *ManagerService) Start(tunnelName string) error {
 			}
 		}()
 	}
-	time.AfterFunc(time.Second*10, cleanupStaleWintunInterfaces)
+	time.AfterFunc(time.Second*10, cleanupStaleNetworkInterfaces)
 
 	// After that process is started -- it's somewhat asynchronous -- we install the new one.
 	c, err := conf.LoadFromName(tunnelName)
@@ -131,7 +154,7 @@ func (s *ManagerService) Start(tunnelName string) error {
 }
 
 func (s *ManagerService) Stop(tunnelName string) error {
-	time.AfterFunc(time.Second*10, cleanupStaleWintunInterfaces)
+	time.AfterFunc(time.Second*10, cleanupStaleNetworkInterfaces)
 
 	err := UninstallTunnel(tunnelName)
 	if err == windows.ERROR_SERVICE_DOES_NOT_EXIST {
diff --git a/manager/service.go b/manager/service.go
index da6ff497..9555d386 100644
--- a/manager/service.go
+++ b/manager/service.go
@@ -254,7 +254,7 @@ func (service *managerService) Execute(args []string, r <-chan svc.ChangeRequest
 		}()
 	}
 
-	time.AfterFunc(time.Second*10, cleanupStaleWintunInterfaces)
+	time.AfterFunc(time.Second*10, cleanupStaleNetworkInterfaces)
 	go checkForUpdates()
 
 	var sessionsPointer *windows.WTS_SESSION_INFO