vpnem: VPN infrastructure with load-balanced multi-protocol nodesHEADmain

- Multi-protocol VPS nodes (VLESS-REALITY + Hysteria2 + SOCKS5)
- Smart load balancing via recommendation API
- Windows/Linux client (Go + Wails + sing-box)
- Server API with RealIP detection and connection tracking
- Auto-deployment via vpnui control plane
- Silent Windows installer with UAC elevation
- Load-based server recommendation (no sticky sessions)
- Best Server one-click connection workflow

2 files changed, 310 insertions, 0 deletions

diff --git a/cmd/installer/elevate_windows.go b/cmd/installer/elevate_windows.go
new file mode 100644
index 0000000..f174390
--- /dev/null
+++ b/cmd/installer/elevate_windows.go
@@ -0,0 +1,74 @@
+//go:build windows
+
+package main
+
+import (
+	"fmt"
+	"os"
+	"strings"
+	"syscall"
+	"unsafe"
+)
+
+var (
+	shell32            = syscall.NewLazyDLL("shell32.dll")
+	shellExecuteW      = shell32.NewProc("ShellExecuteW")
+	isUserAnAdminProc  = shell32.NewProc("IsUserAnAdmin")
+	errCancelledByUser = uintptr(1223)
+)
+
+func isElevated() bool {
+	ret, _, _ := isUserAnAdminProc.Call()
+	return ret != 0
+}
+
+func relaunchElevated() error {
+	exePath, err := os.Executable()
+	if err != nil {
+		return err
+	}
+
+	verb, err := syscall.UTF16PtrFromString("runas")
+	if err != nil {
+		return err
+	}
+	file, err := syscall.UTF16PtrFromString(exePath)
+	if err != nil {
+		return err
+	}
+	args, err := syscall.UTF16PtrFromString(joinWindowsArgs(os.Args[1:]))
+	if err != nil {
+		return err
+	}
+
+	ret, _, callErr := shellExecuteW.Call(
+		0,
+		uintptr(unsafe.Pointer(verb)),
+		uintptr(unsafe.Pointer(file)),
+		uintptr(unsafe.Pointer(args)),
+		0,
+		1,
+	)
+	if ret <= 32 {
+		if ret == errCancelledByUser {
+			return fmt.Errorf("administrator privileges were not granted")
+		}
+		if callErr != syscall.Errno(0) {
+			return fmt.Errorf("ShellExecuteW failed: %w", callErr)
+		}
+		return fmt.Errorf("ShellExecuteW failed with code %d", ret)
+	}
+	return nil
+}
+
+func joinWindowsArgs(args []string) string {
+	if len(args) == 0 {
+		return ""
+	}
+	quoted := make([]string, 0, len(args))
+	for _, arg := range args {
+		escaped := strings.ReplaceAll(arg, `"`, `\"`)
+		quoted = append(quoted, `"`+escaped+`"`)
+	}
+	return strings.Join(quoted, " ")
+}
diff --git a/cmd/installer/main.go b/cmd/installer/main.go
new file mode 100644
index 0000000..07f7fe8
--- /dev/null
+++ b/cmd/installer/main.go
@@ -0,0 +1,236 @@
+// vpnem-installer: Windows offline installer (GUI, no console window).
+// Bundles all binaries — no network download needed.
+// Installs to Program Files, creates Task Scheduler task for UAC-free launch.
+// Requires admin (one-time). Supports silent mode: vpnem-installer.exe /S
+// Cross-compiles from Linux with -ldflags "-H windowsgui"
+package main
+
+import (
+	"embed"
+	"fmt"
+	"log"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"strings"
+	"time"
+)
+
+//go:embed files/*
+var bundledFiles embed.FS
+
+const (
+	installDir = `C:\Program Files\vpnem`
+	dataDir    = `C:\ProgramData\vpnem`
+	taskName   = "vpnem"
+
+	baseURL    = "https://vpn.em-sysadmin.xyz/releases"
+	vpnemURL   = baseURL + "/vpnem-windows-amd64.exe"
+)
+
+var (
+	silent     bool
+	noShortcut bool
+	launch     bool
+	logFile    *os.File
+)
+
+func main() {
+	// Parse flags
+	for _, arg := range os.Args[1:] {
+		a := strings.ToLower(strings.TrimLeft(arg, "/-"))
+		switch a {
+		case "s", "silent":
+			silent = true
+		case "noshortcut":
+			noShortcut = true
+		case "launch":
+			launch = true
+		}
+	}
+
+	if !isElevated() {
+		if err := relaunchElevated(); err != nil {
+			fatal("request administrator privileges: %v", err)
+		}
+		return
+	}
+
+	// 1. Kill ALL running instances immediately
+	step("stopping running instances")
+	exec.Command("taskkill", "/F", "/IM", "vpnem.exe").Run()
+	exec.Command("taskkill", "/F", "/IM", "sing-box.exe").Run()
+	time.Sleep(2 * time.Second)
+
+	// 2. Remove OLD installation directories completely (clean slate)
+	step("removing old installation")
+	if err := os.RemoveAll(installDir); err != nil {
+		log.Printf("warning: could not remove old install dir: %v", err)
+	}
+	if err := os.RemoveAll(dataDir); err != nil {
+		log.Printf("warning: could not remove old data dir: %v", err)
+	}
+	// Also remove old ProxySwitcher if exists
+	os.RemoveAll(`C:\ProxySwitcher`)
+
+	// 3. Create fresh directories
+	if err := os.MkdirAll(installDir, 0o755); err != nil {
+		fatal("create install dir: %v", err)
+	}
+	if err := os.MkdirAll(dataDir, 0o755); err != nil {
+		fatal("create data dir: %v", err)
+	}
+
+	// Write bundled files instead of downloading
+	step("extracting bundled vpnem.exe")
+	if err := writeEmbedded("files/vpnem.exe", filepath.Join(installDir, "vpnem.exe")); err != nil {
+		fatal("extract vpnem.exe: %v", err)
+	}
+	step("extracting bundled sing-box.exe")
+	if err := writeEmbedded("files/sing-box.exe", filepath.Join(installDir, "sing-box.exe")); err != nil {
+		fatal("extract sing-box.exe: %v", err)
+	}
+	step("extracting bundled wintun.dll")
+	if err := writeEmbedded("files/wintun.dll", filepath.Join(installDir, "wintun.dll")); err != nil {
+		fatal("extract wintun.dll: %v", err)
+	}
+
+	// Create Task Scheduler task — runs vpnem as admin WITHOUT UAC prompt.
+	// This is the key: task created by admin runs with highest privileges silently.
+	step("creating scheduled task (UAC-free launch)")
+	createTask()
+
+	// Desktop shortcut — launches via schtasks (no UAC popup)
+	if !noShortcut {
+		step("creating desktop shortcut")
+		createShortcut()
+	}
+
+	step("installation complete")
+
+	if launch {
+		step("launching vpnem")
+		exec.Command("schtasks", "/Run", "/TN", taskName).Run()
+	}
+
+	if !silent {
+		showDoneMessage()
+	}
+}
+
+// createTask sets up a scheduled task that:
+// 1. Runs vpnem.exe with highest privileges (no UAC)
+// 2. Starts at logon with 15s delay (autostart)
+// The same task is used for both manual launch and autostart.
+func createTask() {
+	exec.Command("schtasks", "/Delete", "/TN", taskName, "/F").Run()
+
+	// Create XML task definition for full control
+	exePath := filepath.Join(installDir, "vpnem.exe")
+	xml := fmt.Sprintf(`<?xml version="1.0" encoding="UTF-16"?>
+<Task version="1.2" xmlns="http://schemas.microsoft.com/windows/2004/02/mit/task">
+  <RegistrationInfo>
+    <Description>vpnem VPN client</Description>
+  </RegistrationInfo>
+  <Triggers>
+    <LogonTrigger>
+      <Enabled>true</Enabled>
+      <Delay>PT15S</Delay>
+    </LogonTrigger>
+  </Triggers>
+  <Principals>
+    <Principal>
+      <LogonType>InteractiveToken</LogonType>
+      <RunLevel>HighestAvailable</RunLevel>
+    </Principal>
+  </Principals>
+  <Settings>
+    <MultipleInstancesPolicy>IgnoreNew</MultipleInstancesPolicy>
+    <DisallowStartIfOnBatteries>false</DisallowStartIfOnBatteries>
+    <StopIfGoingOnBatteries>false</StopIfGoingOnBatteries>
+    <ExecutionTimeLimit>PT0S</ExecutionTimeLimit>
+    <AllowStartOnDemand>true</AllowStartOnDemand>
+    <AllowHardTerminate>true</AllowHardTerminate>
+  </Settings>
+  <Actions>
+    <Exec>
+      <Command>%s</Command>
+      <Arguments>--data "%s"</Arguments>
+      <WorkingDirectory>%s</WorkingDirectory>
+    </Exec>
+  </Actions>
+</Task>`, exePath, dataDir, installDir)
+
+	xmlPath := filepath.Join(dataDir, "task.xml")
+	os.WriteFile(xmlPath, []byte(xml), 0o644)
+
+	cmd := exec.Command("schtasks", "/Create", "/TN", taskName, "/XML", xmlPath, "/F")
+	out, err := cmd.CombinedOutput()
+	if err != nil {
+		log.Printf("task create failed: %v\n%s", err, string(out))
+	} else {
+		log.Println("task created ok")
+	}
+	os.Remove(xmlPath)
+}
+
+// createShortcut makes a desktop shortcut that runs the scheduled task (no UAC)
+// IconLocation points to vpnem.exe so the shortcut has the app icon
+func createShortcut() {
+	exePath := filepath.Join(installDir, "vpnem.exe")
+	ps := `
+$ws = New-Object -ComObject WScript.Shell
+$s = $ws.CreateShortcut("$env:USERPROFILE\Desktop\vpnem.lnk")
+$s.TargetPath = "schtasks.exe"
+$s.Arguments = "/Run /TN vpnem"
+$s.WorkingDirectory = "` + installDir + `"
+$s.IconLocation = "` + exePath + `,0"
+$s.Description = "vpnem VPN client"
+$s.Save()
+`
+	cmd := exec.Command("powershell", "-NoProfile", "-WindowStyle", "Hidden", "-Command", ps)
+	if err := cmd.Run(); err != nil {
+		log.Printf("shortcut failed: %v (non-critical)", err)
+	}
+}
+
+func step(msg string) {
+	log.Println(msg)
+}
+
+func writeEmbedded(name, dest string) error {
+	data, err := bundledFiles.ReadFile(name)
+	if err != nil {
+		return fmt.Errorf("read embedded file %s: %w", name, err)
+	}
+	tmp := dest + ".tmp"
+	if err := os.WriteFile(tmp, data, 0o755); err != nil {
+		return fmt.Errorf("write %s: %w", dest, err)
+	}
+	info, _ := os.Stat(tmp)
+	log.Printf("  %s (%.1f MB)", filepath.Base(dest), float64(info.Size())/1024/1024)
+	return os.Rename(tmp, dest)
+}
+
+func fatal(format string, args ...any) {
+	msg := fmt.Sprintf(format, args...)
+	log.Printf("FATAL: %s", msg)
+	if silent {
+		os.Exit(1)
+	}
+	showError(msg)
+	os.Exit(1)
+}
+
+func showDoneMessage() {
+	msg := fmt.Sprintf("vpnem installed to %s\\n\\nDesktop shortcut created.\\nAutostart at logon enabled.\\n\\nNo admin prompts needed to launch.", installDir)
+	exec.Command("powershell", "-NoProfile", "-WindowStyle", "Hidden", "-Command",
+		fmt.Sprintf(`Add-Type -AssemblyName System.Windows.Forms; [System.Windows.Forms.MessageBox]::Show("%s", "vpnem installer", "OK", "Information")`, msg),
+	).Run()
+}
+
+func showError(msg string) {
+	exec.Command("powershell", "-NoProfile", "-WindowStyle", "Hidden", "-Command",
+		fmt.Sprintf(`Add-Type -AssemblyName System.Windows.Forms; [System.Windows.Forms.MessageBox]::Show("Installation failed:\n%s", "vpnem installer", "OK", "Error")`, msg),
+	).Run()
+}