version: unify architecture string handling

Always report native architecture and use "x86" instead of "386" for all
identification strings, except when explicitly stating the Go verison.

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

1 files changed, 55 insertions, 1 deletions

diff --git a/version/useragent.go b/version/useragent.go
index 77633765..e0781e29 100644
--- a/version/useragent.go
+++ b/version/useragent.go
@@ -6,10 +6,64 @@
 package version
 
 import (
+	"debug/pe"
+	"errors"
 	"fmt"
 	"runtime"
+
+	"golang.org/x/sys/windows"
 )
 
+var arch string
+
+func NativeArch() string {
+	if len(arch) > 0 {
+		return arch
+	}
+	var processMachine, nativeMachine uint16
+	err := windows.IsWow64Process2(windows.CurrentProcess(), &processMachine, &nativeMachine)
+	if err != nil && errors.Is(err, windows.ERROR_PROC_NOT_FOUND) {
+		var b bool
+		err = windows.IsWow64Process(windows.CurrentProcess(), &b)
+		if err != nil {
+			panic(err)
+		}
+		if b && runtime.GOARCH == "x86" {
+			nativeMachine = pe.IMAGE_FILE_MACHINE_AMD64
+		} else if b && runtime.GOARCH == "arm" {
+			nativeMachine = pe.IMAGE_FILE_MACHINE_ARM64
+		} else {
+			switch runtime.GOARCH {
+			case "arm":
+				nativeMachine = pe.IMAGE_FILE_MACHINE_ARMNT
+			case "arm64":
+				nativeMachine = pe.IMAGE_FILE_MACHINE_ARM64
+			case "amd64":
+				nativeMachine = pe.IMAGE_FILE_MACHINE_AMD64
+			case "386":
+				nativeMachine = pe.IMAGE_FILE_MACHINE_I386
+			default:
+				panic("Unrecognized GOARCH")
+			}
+		}
+	} else if err != nil {
+		panic(err)
+	}
+	switch nativeMachine {
+	case pe.IMAGE_FILE_MACHINE_ARMNT:
+		arch = "arm"
+	case pe.IMAGE_FILE_MACHINE_ARM64:
+		arch = "arm64"
+	case pe.IMAGE_FILE_MACHINE_AMD64:
+		arch = "amd64"
+	case pe.IMAGE_FILE_MACHINE_I386:
+		arch = "x86"
+	default:
+		panic("Unrecognized machine type")
+	}
+	return arch
+}
+
 func UserAgent() string {
-	return fmt.Sprintf("WireGuard/%s (%s; %s)", Number, OsName(), runtime.GOARCH)
+	return fmt.Sprintf("WireGuard/%s (%s; %s)", Number, OsName(), NativeArch())
 }