manager: pipeline UAPI requests

This avoids the somewhat expensive pipe setup.

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

3 files changed, 88 insertions, 19 deletions

diff --git a/manager/ipc_server.go b/manager/ipc_server.go
index 19298016..ccdfe85e 100644
--- a/manager/ipc_server.go
+++ b/manager/ipc_server.go
@@ -10,7 +10,6 @@ import (
 	"encoding/gob"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"log"
 	"os"
 	"sync"
@@ -20,8 +19,6 @@ import (
 	"golang.org/x/sys/windows"
 	"golang.org/x/sys/windows/svc"
 
-	"golang.zx2c4.com/wireguard/ipc/winpipe"
-
 	"golang.zx2c4.com/wireguard/windows/conf"
 	"golang.zx2c4.com/wireguard/windows/services"
 	"golang.zx2c4.com/wireguard/windows/updater"
@@ -54,30 +51,30 @@ func (s *ManagerService) RuntimeConfig(tunnelName string) (*conf.Config, error)
 	if err != nil {
 		return nil, err
 	}
-	pipePath, err := services.PipePathOfTunnel(storedConfig.Name)
-	if err != nil {
-		return nil, err
-	}
-	localSystem, err := windows.CreateWellKnownSid(windows.WinLocalSystemSid)
+	pipe, err := connectTunnelServicePipe(tunnelName)
 	if err != nil {
 		return nil, err
 	}
-	pipe, err := winpipe.DialPipe(pipePath, nil, localSystem)
-	if err != nil {
-		return nil, err
-	}
-	defer pipe.Close()
-	pipe.SetWriteDeadline(time.Now().Add(time.Second * 2))
+	pipe.SetDeadline(time.Now().Add(time.Second * 2))
 	_, err = pipe.Write([]byte("get=1\n\n"))
-	if err != nil {
-		return nil, err
+	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"))
 	}
-	pipe.SetReadDeadline(time.Now().Add(time.Second * 2))
-	resp, err := ioutil.ReadAll(pipe)
 	if err != nil {
+		pipe.Unlock()
+		disconnectTunnelServicePipe(tunnelName)
 		return nil, err
 	}
-	conf, err := conf.FromUAPI(string(resp), storedConfig)
+	conf, err := conf.FromUAPI(pipe, storedConfig)
+	pipe.Unlock()
 	if err != nil {
 		return nil, err
 	}
diff --git a/manager/ipc_uapi.go b/manager/ipc_uapi.go
new file mode 100644
index 00000000..b339e3ac
--- /dev/null
+++ b/manager/ipc_uapi.go
@@ -0,0 +1,71 @@
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright (C) 2019-2021 WireGuard LLC. All Rights Reserved.
+ */
+
+package manager
+
+import (
+	"net"
+	"sync"
+
+	"golang.org/x/sys/windows"
+	"golang.zx2c4.com/wireguard/ipc/winpipe"
+
+	"golang.zx2c4.com/wireguard/windows/services"
+)
+
+type connectedTunnel struct {
+	net.Conn
+	sync.Mutex
+}
+
+var connectedTunnelServicePipes = make(map[string]*connectedTunnel)
+var connectedTunnelServicePipesLock sync.RWMutex
+
+func connectTunnelServicePipe(tunnelName string) (*connectedTunnel, error) {
+	connectedTunnelServicePipesLock.RLock()
+	pipe, ok := connectedTunnelServicePipes[tunnelName]
+	if ok {
+		pipe.Lock()
+		connectedTunnelServicePipesLock.RUnlock()
+		return pipe, nil
+	}
+	connectedTunnelServicePipesLock.RUnlock()
+	connectedTunnelServicePipesLock.Lock()
+	defer connectedTunnelServicePipesLock.Unlock()
+	pipe, ok = connectedTunnelServicePipes[tunnelName]
+	if ok {
+		pipe.Lock()
+		return pipe, nil
+	}
+	pipePath, err := services.PipePathOfTunnel(tunnelName)
+	if err != nil {
+		return nil, err
+	}
+	localSystem, err := windows.CreateWellKnownSid(windows.WinLocalSystemSid)
+	if err != nil {
+		return nil, err
+	}
+	pipe = &connectedTunnel{}
+	pipe.Conn, err = winpipe.DialPipe(pipePath, nil, localSystem)
+	if err != nil {
+		return nil, err
+	}
+	connectedTunnelServicePipes[tunnelName] = pipe
+	pipe.Lock()
+	return pipe, nil
+}
+
+func disconnectTunnelServicePipe(tunnelName string) {
+	connectedTunnelServicePipesLock.Lock()
+	defer connectedTunnelServicePipesLock.Unlock()
+	pipe, ok := connectedTunnelServicePipes[tunnelName]
+	if !ok {
+		return
+	}
+	pipe.Lock()
+	pipe.Close()
+	delete(connectedTunnelServicePipes, tunnelName)
+	pipe.Unlock()
+}
diff --git a/manager/tunneltracker.go b/manager/tunneltracker.go
index cfd28693..4625a8e8 100644
--- a/manager/tunneltracker.go
+++ b/manager/tunneltracker.go
@@ -273,4 +273,5 @@ func trackTunnelService(tunnelName string, service *mgr.Service) {
 		IPCServerNotifyTunnelChange(tunnelName, TunnelStopped, fmt.Errorf("Unable to continue monitoring service, so stopping: %w", err))
 		service.Control(svc.Stop)
 	}
+	disconnectTunnelServicePipe(tunnelName)
 }