diff --git a/Android/app/build.gradle b/Android/app/build.gradle
index ad822e07..a6d2bd73 100644
--- a/Android/app/build.gradle
+++ b/Android/app/build.gradle
@@ -15,6 +15,31 @@ try {
     keystoreProperties['storePassword'] = ''
 }
 
+// Go backend build constants
+def goSourceDir = "${projectDir}/src/go"
+def goSourcePackages = ["${goSourceDir}/intra",
+                        "${goSourceDir}/intra/android",
+                        "${goSourceDir}/intra/doh",
+                        "${goSourceDir}/intra/split",
+                        "${goSourceDir}/intra/protect"]
+def goBuildDir = file("${buildDir}/go")
+def goBackendAAR = file("${goBuildDir}/backend.aar")
+
+// gomobile won't use the Go version in go.mod. So we need to manually read it from go.mod and
+// explicitly set the GOTOOLCHAIN environment variable later.
+def goModLines = new File("${rootDir}/../go.mod").readLines()
+def goToolchain = goModLines.find { it.startsWith('toolchain ') }
+if (goToolchain == null) {
+    goToolchain = goModLines.find { it.startsWith('go ') }
+    if (goToolchain == null) {
+        throw new GradleException('cannot locate Go toolchain version in go.mod')
+    }
+}
+// goToolchain: ['toolchain go1.x.y' or 'go 1.x.y'] -> 'go1.x.y'
+goToolchain = goToolchain.replace("toolchain", "").replace(" ", "")
+println "using Go toolchain ${goToolchain}"
+
+// Standard Android build definition
 android {
     signingConfigs {
         config {
@@ -106,10 +131,51 @@ dependencies {
     implementation 'com.google.firebase:firebase-crashlytics:18.2.6'
     implementation 'com.google.firebase:firebase-crashlytics-ndk:18.2.6'
     implementation 'com.google.firebase:firebase-config:21.0.1'
-    // For go-tun2socks
-    implementation project(path: ':tun2socks', configuration: 'aarBinary')
+
+    // Go backend (use fileTree instead of files to prevent Android Studio sync errors)
+    implementation fileTree(goBuildDir) {
+        include '*.aar'
+        builtBy 'compileGoBackend'
+    }
 }
 
 // For Firebase Analytics
 apply plugin: 'com.google.gms.google-services'
 apply plugin: 'com.google.firebase.firebase-perf'
+
+// Go backend build tasks
+tasks.register('compileGoBackend', Exec) {
+    dependsOn 'ensureGoMobile'
+
+    // invoke gomobile to compile backend code
+    inputs.dir(goSourceDir)
+    outputs.file(goBackendAAR)
+
+    environment 'GOTOOLCHAIN', goToolchain
+    environment 'ANDROID_HOME', android.sdkDirectory
+    environment 'PATH', goBuildDir.getPath() +
+                        System.getProperty('path.separator') +
+                        System.getenv('PATH')
+
+    commandLine("${goBuildDir}/gomobile", 'bind',
+                '-ldflags=-s -w',
+                '-target=android',
+                "-androidapi=${android.defaultConfig.minSdk}",
+                '-o', goBackendAAR,
+                *goSourcePackages)
+}
+
+tasks.register('ensureGoMobile', Exec) {
+    // install gomobile and gobind into the build folder
+    outputs.file("${goBuildDir}/gomobile")
+    outputs.file("${goBuildDir}/gobind")
+
+    doFirst { goBuildDir.mkdirs() }
+
+    environment 'GOTOOLCHAIN', goToolchain
+
+    commandLine('go', 'build',
+                '-o', goBuildDir,
+                'golang.org/x/mobile/cmd/gomobile',
+                'golang.org/x/mobile/cmd/gobind')
+}
diff --git a/Android/tun2socks/intra/android/init.go b/Android/app/src/go/intra/android/init.go
similarity index 100%
rename from Android/tun2socks/intra/android/init.go
rename to Android/app/src/go/intra/android/init.go
diff --git a/Android/tun2socks/intra/android/tun.go b/Android/app/src/go/intra/android/tun.go
similarity index 100%
rename from Android/tun2socks/intra/android/tun.go
rename to Android/app/src/go/intra/android/tun.go
diff --git a/Android/tun2socks/intra/android/tun2socks.go b/Android/app/src/go/intra/android/tun2socks.go
similarity index 95%
rename from Android/tun2socks/intra/android/tun2socks.go
rename to Android/app/src/go/intra/android/tun2socks.go
index f709e279..df483d47 100644
--- a/Android/tun2socks/intra/android/tun2socks.go
+++ b/Android/app/src/go/intra/android/tun2socks.go
@@ -22,9 +22,9 @@ import (
 	"os"
 	"strings"
 
-	"github.com/Jigsaw-Code/Intra/Android/tun2socks/intra"
-	"github.com/Jigsaw-Code/Intra/Android/tun2socks/intra/doh"
-	"github.com/Jigsaw-Code/Intra/Android/tun2socks/intra/protect"
+	"github.com/Jigsaw-Code/Intra/Android/app/src/go/intra"
+	"github.com/Jigsaw-Code/Intra/Android/app/src/go/intra/doh"
+	"github.com/Jigsaw-Code/Intra/Android/app/src/go/intra/protect"
 	"github.com/Jigsaw-Code/outline-sdk/network"
 )
 
diff --git a/Android/tun2socks/intra/doh/atomic.go b/Android/app/src/go/intra/doh/atomic.go
similarity index 100%
rename from Android/tun2socks/intra/doh/atomic.go
rename to Android/app/src/go/intra/doh/atomic.go
diff --git a/Android/tun2socks/intra/doh/client_auth.go b/Android/app/src/go/intra/doh/client_auth.go
similarity index 100%
rename from Android/tun2socks/intra/doh/client_auth.go
rename to Android/app/src/go/intra/doh/client_auth.go
diff --git a/Android/tun2socks/intra/doh/client_auth_test.go b/Android/app/src/go/intra/doh/client_auth_test.go
similarity index 100%
rename from Android/tun2socks/intra/doh/client_auth_test.go
rename to Android/app/src/go/intra/doh/client_auth_test.go
diff --git a/Android/tun2socks/intra/doh/doh.go b/Android/app/src/go/intra/doh/doh.go
similarity index 99%
rename from Android/tun2socks/intra/doh/doh.go
rename to Android/app/src/go/intra/doh/doh.go
index 082ce656..6242ef51 100644
--- a/Android/tun2socks/intra/doh/doh.go
+++ b/Android/app/src/go/intra/doh/doh.go
@@ -32,8 +32,8 @@ import (
 	"sync"
 	"time"
 
-	"github.com/Jigsaw-Code/Intra/Android/tun2socks/intra/doh/ipmap"
-	"github.com/Jigsaw-Code/Intra/Android/tun2socks/intra/split"
+	"github.com/Jigsaw-Code/Intra/Android/app/src/go/intra/doh/ipmap"
+	"github.com/Jigsaw-Code/Intra/Android/app/src/go/intra/split"
 	"github.com/eycorsican/go-tun2socks/common/log"
 	"golang.org/x/net/dns/dnsmessage"
 )
diff --git a/Android/tun2socks/intra/doh/doh_test.go b/Android/app/src/go/intra/doh/doh_test.go
similarity index 100%
rename from Android/tun2socks/intra/doh/doh_test.go
rename to Android/app/src/go/intra/doh/doh_test.go
diff --git a/Android/tun2socks/intra/doh/ipmap/ipmap.go b/Android/app/src/go/intra/doh/ipmap/ipmap.go
similarity index 100%
rename from Android/tun2socks/intra/doh/ipmap/ipmap.go
rename to Android/app/src/go/intra/doh/ipmap/ipmap.go
diff --git a/Android/tun2socks/intra/doh/ipmap/ipmap_test.go b/Android/app/src/go/intra/doh/ipmap/ipmap_test.go
similarity index 100%
rename from Android/tun2socks/intra/doh/ipmap/ipmap_test.go
rename to Android/app/src/go/intra/doh/ipmap/ipmap_test.go
diff --git a/Android/tun2socks/intra/doh/padding.go b/Android/app/src/go/intra/doh/padding.go
similarity index 100%
rename from Android/tun2socks/intra/doh/padding.go
rename to Android/app/src/go/intra/doh/padding.go
diff --git a/Android/tun2socks/intra/ip.go b/Android/app/src/go/intra/ip.go
similarity index 100%
rename from Android/tun2socks/intra/ip.go
rename to Android/app/src/go/intra/ip.go
diff --git a/Android/tun2socks/intra/ip_test.go b/Android/app/src/go/intra/ip_test.go
similarity index 100%
rename from Android/tun2socks/intra/ip_test.go
rename to Android/app/src/go/intra/ip_test.go
diff --git a/Android/tun2socks/intra/packet_proxy.go b/Android/app/src/go/intra/packet_proxy.go
similarity index 97%
rename from Android/tun2socks/intra/packet_proxy.go
rename to Android/app/src/go/intra/packet_proxy.go
index c5f39b63..5232857a 100644
--- a/Android/tun2socks/intra/packet_proxy.go
+++ b/Android/app/src/go/intra/packet_proxy.go
@@ -22,8 +22,8 @@ import (
 	"sync/atomic"
 	"time"
 
-	"github.com/Jigsaw-Code/Intra/Android/tun2socks/intra/doh"
-	"github.com/Jigsaw-Code/Intra/Android/tun2socks/intra/protect"
+	"github.com/Jigsaw-Code/Intra/Android/app/src/go/intra/doh"
+	"github.com/Jigsaw-Code/Intra/Android/app/src/go/intra/protect"
 	"github.com/Jigsaw-Code/outline-sdk/network"
 	"github.com/Jigsaw-Code/outline-sdk/transport"
 )
diff --git a/Android/tun2socks/intra/protect/protect.go b/Android/app/src/go/intra/protect/protect.go
similarity index 100%
rename from Android/tun2socks/intra/protect/protect.go
rename to Android/app/src/go/intra/protect/protect.go
diff --git a/Android/tun2socks/intra/protect/protect_test.go b/Android/app/src/go/intra/protect/protect_test.go
similarity index 100%
rename from Android/tun2socks/intra/protect/protect_test.go
rename to Android/app/src/go/intra/protect/protect_test.go
diff --git a/Android/tun2socks/intra/sni_reporter.go b/Android/app/src/go/intra/sni_reporter.go
similarity index 98%
rename from Android/tun2socks/intra/sni_reporter.go
rename to Android/app/src/go/intra/sni_reporter.go
index 3ac5a109..4346721a 100644
--- a/Android/tun2socks/intra/sni_reporter.go
+++ b/Android/app/src/go/intra/sni_reporter.go
@@ -19,7 +19,7 @@ import (
 	"sync"
 	"time"
 
-	"github.com/Jigsaw-Code/Intra/Android/tun2socks/intra/doh"
+	"github.com/Jigsaw-Code/Intra/Android/app/src/go/intra/doh"
 	"github.com/Jigsaw-Code/choir"
 	"github.com/eycorsican/go-tun2socks/common/log"
 )
diff --git a/Android/tun2socks/intra/sni_reporter_test.go b/Android/app/src/go/intra/sni_reporter_test.go
similarity index 97%
rename from Android/tun2socks/intra/sni_reporter_test.go
rename to Android/app/src/go/intra/sni_reporter_test.go
index 9da76b44..9826dd1c 100644
--- a/Android/tun2socks/intra/sni_reporter_test.go
+++ b/Android/app/src/go/intra/sni_reporter_test.go
@@ -22,8 +22,8 @@ import (
 
 	"golang.org/x/net/dns/dnsmessage"
 
-	"github.com/Jigsaw-Code/Intra/Android/tun2socks/intra/doh"
-	"github.com/Jigsaw-Code/Intra/Android/tun2socks/intra/split"
+	"github.com/Jigsaw-Code/Intra/Android/app/src/go/intra/doh"
+	"github.com/Jigsaw-Code/Intra/Android/app/src/go/intra/split"
 )
 
 type qfunc func(q []byte) ([]byte, error)
diff --git a/Android/tun2socks/intra/split/direct_split.go b/Android/app/src/go/intra/split/direct_split.go
similarity index 100%
rename from Android/tun2socks/intra/split/direct_split.go
rename to Android/app/src/go/intra/split/direct_split.go
diff --git a/Android/tun2socks/intra/split/example/main.go b/Android/app/src/go/intra/split/example/main.go
similarity index 97%
rename from Android/tun2socks/intra/split/example/main.go
rename to Android/app/src/go/intra/split/example/main.go
index 850662af..9644e5f1 100644
--- a/Android/tun2socks/intra/split/example/main.go
+++ b/Android/app/src/go/intra/split/example/main.go
@@ -22,7 +22,7 @@ import (
 	"net"
 	"os"
 
-	"github.com/Jigsaw-Code/Intra/Android/tun2socks/intra/split"
+	"github.com/Jigsaw-Code/Intra/Android/app/src/go/intra/split"
 )
 
 func main() {
diff --git a/Android/tun2socks/intra/split/retrier.go b/Android/app/src/go/intra/split/retrier.go
similarity index 100%
rename from Android/tun2socks/intra/split/retrier.go
rename to Android/app/src/go/intra/split/retrier.go
diff --git a/Android/tun2socks/intra/split/retrier_test.go b/Android/app/src/go/intra/split/retrier_test.go
similarity index 100%
rename from Android/tun2socks/intra/split/retrier_test.go
rename to Android/app/src/go/intra/split/retrier_test.go
diff --git a/Android/tun2socks/intra/stream_dialer.go b/Android/app/src/go/intra/stream_dialer.go
similarity index 95%
rename from Android/tun2socks/intra/stream_dialer.go
rename to Android/app/src/go/intra/stream_dialer.go
index aee50b13..2d27466d 100644
--- a/Android/tun2socks/intra/stream_dialer.go
+++ b/Android/app/src/go/intra/stream_dialer.go
@@ -23,9 +23,9 @@ import (
 	"sync/atomic"
 	"time"
 
-	"github.com/Jigsaw-Code/Intra/Android/tun2socks/intra/doh"
-	"github.com/Jigsaw-Code/Intra/Android/tun2socks/intra/protect"
-	"github.com/Jigsaw-Code/Intra/Android/tun2socks/intra/split"
+	"github.com/Jigsaw-Code/Intra/Android/app/src/go/intra/doh"
+	"github.com/Jigsaw-Code/Intra/Android/app/src/go/intra/protect"
+	"github.com/Jigsaw-Code/Intra/Android/app/src/go/intra/split"
 	"github.com/Jigsaw-Code/outline-sdk/transport"
 )
 
diff --git a/Android/tun2socks/intra/tcp.go b/Android/app/src/go/intra/tcp.go
similarity index 98%
rename from Android/tun2socks/intra/tcp.go
rename to Android/app/src/go/intra/tcp.go
index 7b252364..f61631d2 100644
--- a/Android/tun2socks/intra/tcp.go
+++ b/Android/app/src/go/intra/tcp.go
@@ -23,7 +23,7 @@ import (
 	"sync/atomic"
 	"time"
 
-	"github.com/Jigsaw-Code/Intra/Android/tun2socks/intra/split"
+	"github.com/Jigsaw-Code/Intra/Android/app/src/go/intra/split"
 	"github.com/Jigsaw-Code/outline-sdk/transport"
 )
 
diff --git a/Android/tun2socks/intra/tunnel.go b/Android/app/src/go/intra/tunnel.go
similarity index 96%
rename from Android/tun2socks/intra/tunnel.go
rename to Android/app/src/go/intra/tunnel.go
index ae7abcc6..0d79e022 100644
--- a/Android/tun2socks/intra/tunnel.go
+++ b/Android/app/src/go/intra/tunnel.go
@@ -22,8 +22,8 @@ import (
 	"os"
 	"strings"
 
-	"github.com/Jigsaw-Code/Intra/Android/tun2socks/intra/doh"
-	"github.com/Jigsaw-Code/Intra/Android/tun2socks/intra/protect"
+	"github.com/Jigsaw-Code/Intra/Android/app/src/go/intra/doh"
+	"github.com/Jigsaw-Code/Intra/Android/app/src/go/intra/protect"
 	"github.com/Jigsaw-Code/outline-sdk/network"
 	"github.com/Jigsaw-Code/outline-sdk/network/lwip2transport"
 )
diff --git a/Android/tun2socks/intra/udp.go b/Android/app/src/go/intra/udp.go
similarity index 100%
rename from Android/tun2socks/intra/udp.go
rename to Android/app/src/go/intra/udp.go
diff --git a/Android/gradle.properties b/Android/gradle.properties
index 4bd4909d..70dae5be 100644
--- a/Android/gradle.properties
+++ b/Android/gradle.properties
@@ -10,7 +10,10 @@
 # Specifies the JVM arguments used for the daemon process.
 # The setting is particularly useful for tweaking memory settings.
 # Default value: -Xmx10248m -XX:MaxPermSize=256m
-# org.gradle.jvmargs=-Xmx2048m -XX:MaxPermSize=512m -XX:+HeapDumpOnOutOfMemoryError -Dfile.encoding=UTF-8
+# Increase gradle heap size to 2G to prevent OutOfMemoryError
+org.gradle.jvmargs=-Xmx2048m
+# Other values include:
+# -XX:MaxPermSize=512m -XX:+HeapDumpOnOutOfMemoryError -Dfile.encoding=UTF-8
 
 # When configured, Gradle will run in incubating parallel mode.
 # This option should only be used with decoupled projects. More details, visit
diff --git a/Android/gradle/wrapper/gradle-wrapper.jar b/Android/gradle/wrapper/gradle-wrapper.jar
index 13372aef..7454180f 100644
Binary files a/Android/gradle/wrapper/gradle-wrapper.jar and b/Android/gradle/wrapper/gradle-wrapper.jar differ
diff --git a/Android/gradle/wrapper/gradle-wrapper.properties b/Android/gradle/wrapper/gradle-wrapper.properties
index 3e7e07d7..ffed3a25 100644
--- a/Android/gradle/wrapper/gradle-wrapper.properties
+++ b/Android/gradle/wrapper/gradle-wrapper.properties
@@ -1,6 +1,5 @@
-#Fri Jan 29 10:30:35 EST 2021
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
+distributionUrl=https\://services.gradle.org/distributions/gradle-7.2-bin.zip
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-7.0.2-all.zip
diff --git a/Android/gradlew b/Android/gradlew
index 9d82f789..1b6c7873 100755
--- a/Android/gradlew
+++ b/Android/gradlew
@@ -1,74 +1,129 @@
-#!/usr/bin/env bash
+#!/bin/sh
+
+#
+# Copyright © 2015-2021 the original authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
 
 ##############################################################################
-##
-##  Gradle start up script for UN*X
-##
+#
+#   Gradle start up script for POSIX generated by Gradle.
+#
+#   Important for running:
+#
+#   (1) You need a POSIX-compliant shell to run this script. If your /bin/sh is
+#       noncompliant, but you have some other compliant shell such as ksh or
+#       bash, then to run this script, type that shell name before the whole
+#       command line, like:
+#
+#           ksh Gradle
+#
+#       Busybox and similar reduced shells will NOT work, because this script
+#       requires all of these POSIX shell features:
+#         * functions;
+#         * expansions «$var», «${var}», «${var:-default}», «${var+SET}»,
+#           «${var#prefix}», «${var%suffix}», and «$( cmd )»;
+#         * compound commands having a testable exit status, especially «case»;
+#         * various built-in commands including «command», «set», and «ulimit».
+#
+#   Important for patching:
+#
+#   (2) This script targets any POSIX shell, so it avoids extensions provided
+#       by Bash, Ksh, etc; in particular arrays are avoided.
+#
+#       The "traditional" practice of packing multiple parameters into a
+#       space-separated string is a well documented source of bugs and security
+#       problems, so this is (mostly) avoided, by progressively accumulating
+#       options in "$@", and eventually passing that to Java.
+#
+#       Where the inherited environment variables (DEFAULT_JVM_OPTS, JAVA_OPTS,
+#       and GRADLE_OPTS) rely on word-splitting, this is performed explicitly;
+#       see the in-line comments for details.
+#
+#       There are tweaks for specific operating systems such as AIX, CygWin,
+#       Darwin, MinGW, and NonStop.
+#
+#   (3) This script is generated from the Groovy template
+#       https://github.com/gradle/gradle/blob/master/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
+#       within the Gradle project.
+#
+#       You can find Gradle at https://github.com/gradle/gradle/.
+#
 ##############################################################################
 
-# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-DEFAULT_JVM_OPTS=""
+# Attempt to set APP_HOME
+
+# Resolve links: $0 may be a link
+app_path=$0
+
+# Need this for daisy-chained symlinks.
+while
+    APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
+    [ -h "$app_path" ]
+do
+    ls=$( ls -ld "$app_path" )
+    link=${ls#*' -> '}
+    case $link in             #(
+      /*)   app_path=$link ;; #(
+      *)    app_path=$APP_HOME$link ;;
+    esac
+done
+
+APP_HOME=$( cd "${APP_HOME:-./}" && pwd -P ) || exit
 
 APP_NAME="Gradle"
-APP_BASE_NAME=`basename "$0"`
+APP_BASE_NAME=${0##*/}
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
 
 # Use the maximum available, or set MAX_FD != -1 to use that value.
-MAX_FD="maximum"
+MAX_FD=maximum
 
-warn ( ) {
+warn () {
     echo "$*"
-}
+} >&2
 
-die ( ) {
+die () {
     echo
     echo "$*"
     echo
     exit 1
-}
+} >&2
 
 # OS specific support (must be 'true' or 'false').
 cygwin=false
 msys=false
 darwin=false
-case "`uname`" in
-  CYGWIN* )
-    cygwin=true
-    ;;
-  Darwin* )
-    darwin=true
-    ;;
-  MINGW* )
-    msys=true
-    ;;
+nonstop=false
+case "$( uname )" in                #(
+  CYGWIN* )         cygwin=true  ;; #(
+  Darwin* )         darwin=true  ;; #(
+  MSYS* | MINGW* )  msys=true    ;; #(
+  NONSTOP* )        nonstop=true ;;
 esac
 
-# Attempt to set APP_HOME
-# Resolve links: $0 may be a link
-PRG="$0"
-# Need this for relative symlinks.
-while [ -h "$PRG" ] ; do
-    ls=`ls -ld "$PRG"`
-    link=`expr "$ls" : '.*-> \(.*\)$'`
-    if expr "$link" : '/.*' > /dev/null; then
-        PRG="$link"
-    else
-        PRG=`dirname "$PRG"`"/$link"
-    fi
-done
-SAVED="`pwd`"
-cd "`dirname \"$PRG\"`/" >/dev/null
-APP_HOME="`pwd -P`"
-cd "$SAVED" >/dev/null
-
 CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
 
+
 # Determine the Java command to use to start the JVM.
 if [ -n "$JAVA_HOME" ] ; then
     if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
         # IBM's JDK on AIX uses strange locations for the executables
-        JAVACMD="$JAVA_HOME/jre/sh/java"
+        JAVACMD=$JAVA_HOME/jre/sh/java
     else
-        JAVACMD="$JAVA_HOME/bin/java"
+        JAVACMD=$JAVA_HOME/bin/java
     fi
     if [ ! -x "$JAVACMD" ] ; then
         die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
@@ -77,7 +132,7 @@ Please set the JAVA_HOME variable in your environment to match the
 location of your Java installation."
     fi
 else
-    JAVACMD="java"
+    JAVACMD=java
     which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
 
 Please set the JAVA_HOME variable in your environment to match the
@@ -85,76 +140,95 @@ location of your Java installation."
 fi
 
 # Increase the maximum file descriptors if we can.
-if [ "$cygwin" = "false" -a "$darwin" = "false" ] ; then
-    MAX_FD_LIMIT=`ulimit -H -n`
-    if [ $? -eq 0 ] ; then
-        if [ "$MAX_FD" = "maximum" -o "$MAX_FD" = "max" ] ; then
-            MAX_FD="$MAX_FD_LIMIT"
-        fi
-        ulimit -n $MAX_FD
-        if [ $? -ne 0 ] ; then
-            warn "Could not set maximum file descriptor limit: $MAX_FD"
-        fi
-    else
-        warn "Could not query maximum file descriptor limit: $MAX_FD_LIMIT"
-    fi
+if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then
+    case $MAX_FD in #(
+      max*)
+        MAX_FD=$( ulimit -H -n ) ||
+            warn "Could not query maximum file descriptor limit"
+    esac
+    case $MAX_FD in  #(
+      '' | soft) :;; #(
+      *)
+        ulimit -n "$MAX_FD" ||
+            warn "Could not set maximum file descriptor limit to $MAX_FD"
+    esac
 fi
 
-# For Darwin, add options to specify how the application appears in the dock
-if $darwin; then
-    GRADLE_OPTS="$GRADLE_OPTS \"-Xdock:name=$APP_NAME\" \"-Xdock:icon=$APP_HOME/media/gradle.icns\""
-fi
+# Collect all arguments for the java command, stacking in reverse order:
+#   * args from the command line
+#   * the main class name
+#   * -classpath
+#   * -D...appname settings
+#   * --module-path (only if needed)
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, and GRADLE_OPTS environment variables.
+
+# For Cygwin or MSYS, switch paths to Windows format before running java
+if "$cygwin" || "$msys" ; then
+    APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
+    CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
+
+    JAVACMD=$( cygpath --unix "$JAVACMD" )
 
-# For Cygwin, switch paths to Windows format before running java
-if $cygwin ; then
-    APP_HOME=`cygpath --path --mixed "$APP_HOME"`
-    CLASSPATH=`cygpath --path --mixed "$CLASSPATH"`
-    JAVACMD=`cygpath --unix "$JAVACMD"`
-
-    # We build the pattern for arguments to be converted via cygpath
-    ROOTDIRSRAW=`find -L / -maxdepth 1 -mindepth 1 -type d 2>/dev/null`
-    SEP=""
-    for dir in $ROOTDIRSRAW ; do
-        ROOTDIRS="$ROOTDIRS$SEP$dir"
-        SEP="|"
-    done
-    OURCYGPATTERN="(^($ROOTDIRS))"
-    # Add a user-defined pattern to the cygpath arguments
-    if [ "$GRADLE_CYGPATTERN" != "" ] ; then
-        OURCYGPATTERN="$OURCYGPATTERN|($GRADLE_CYGPATTERN)"
-    fi
     # Now convert the arguments - kludge to limit ourselves to /bin/sh
-    i=0
-    for arg in "$@" ; do
-        CHECK=`echo "$arg"|egrep -c "$OURCYGPATTERN" -`
-        CHECK2=`echo "$arg"|egrep -c "^-"`                                 ### Determine if an option
-
-        if [ $CHECK -ne 0 ] && [ $CHECK2 -eq 0 ] ; then                    ### Added a condition
-            eval `echo args$i`=`cygpath --path --ignore --mixed "$arg"`
-        else
-            eval `echo args$i`="\"$arg\""
+    for arg do
+        if
+            case $arg in                                #(
+              -*)   false ;;                            # don't mess with options #(
+              /?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
+                    [ -e "$t" ] ;;                      #(
+              *)    false ;;
+            esac
+        then
+            arg=$( cygpath --path --ignore --mixed "$arg" )
         fi
-        i=$((i+1))
+        # Roll the args list around exactly as many times as the number of
+        # args, so each arg winds up back in the position where it started, but
+        # possibly modified.
+        #
+        # NB: a `for` loop captures its iteration list before it begins, so
+        # changing the positional parameters here affects neither the number of
+        # iterations, nor the values presented in `arg`.
+        shift                   # remove old arg
+        set -- "$@" "$arg"      # push replacement arg
     done
-    case $i in
-        (0) set -- ;;
-        (1) set -- "$args0" ;;
-        (2) set -- "$args0" "$args1" ;;
-        (3) set -- "$args0" "$args1" "$args2" ;;
-        (4) set -- "$args0" "$args1" "$args2" "$args3" ;;
-        (5) set -- "$args0" "$args1" "$args2" "$args3" "$args4" ;;
-        (6) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" ;;
-        (7) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" ;;
-        (8) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" ;;
-        (9) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" "$args8" ;;
-    esac
 fi
 
-# Split up the JVM_OPTS And GRADLE_OPTS values into an array, following the shell quoting and substitution rules
-function splitJvmOpts() {
-    JVM_OPTS=("$@")
-}
-eval splitJvmOpts $DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS
-JVM_OPTS[${#JVM_OPTS[*]}]="-Dorg.gradle.appname=$APP_BASE_NAME"
-
-exec "$JAVACMD" "${JVM_OPTS[@]}" -classpath "$CLASSPATH" org.gradle.wrapper.GradleWrapperMain "$@"
+# Collect all arguments for the java command;
+#   * $DEFAULT_JVM_OPTS, $JAVA_OPTS, and $GRADLE_OPTS can contain fragments of
+#     shell script including quotes and variable substitutions, so put them in
+#     double quotes to make sure that they get re-expanded; and
+#   * put everything else in single quotes, so that it's not re-expanded.
+
+set -- \
+        "-Dorg.gradle.appname=$APP_BASE_NAME" \
+        -classpath "$CLASSPATH" \
+        org.gradle.wrapper.GradleWrapperMain \
+        "$@"
+
+# Use "xargs" to parse quoted args.
+#
+# With -n1 it outputs one arg per line, with the quotes and backslashes removed.
+#
+# In Bash we could simply go:
+#
+#   readarray ARGS < <( xargs -n1 <<<"$var" ) &&
+#   set -- "${ARGS[@]}" "$@"
+#
+# but POSIX shell has neither arrays nor command substitution, so instead we
+# post-process each arg (as a line of input to sed) to backslash-escape any
+# character that might be a shell metacharacter, then use eval to reverse
+# that process (while maintaining the separation between arguments), and wrap
+# the whole thing up as a single "set" statement.
+#
+# This will of course break if any of these variables contains a newline or
+# an unmatched quote.
+#
+
+eval "set -- $(
+        printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
+        xargs -n1 |
+        sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
+        tr '\n' ' '
+    )" '"$@"'
+
+exec "$JAVACMD" "$@"
diff --git a/Android/gradlew.bat b/Android/gradlew.bat
index aec99730..ac1b06f9 100644
--- a/Android/gradlew.bat
+++ b/Android/gradlew.bat
@@ -1,3 +1,19 @@
+@rem
+@rem Copyright 2015 the original author or authors.
+@rem
+@rem Licensed under the Apache License, Version 2.0 (the "License");
+@rem you may not use this file except in compliance with the License.
+@rem You may obtain a copy of the License at
+@rem
+@rem      https://www.apache.org/licenses/LICENSE-2.0
+@rem
+@rem Unless required by applicable law or agreed to in writing, software
+@rem distributed under the License is distributed on an "AS IS" BASIS,
+@rem WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+@rem See the License for the specific language governing permissions and
+@rem limitations under the License.
+@rem
+
 @if "%DEBUG%" == "" @echo off
 @rem ##########################################################################
 @rem
@@ -8,20 +24,23 @@
 @rem Set local scope for the variables with windows NT shell
 if "%OS%"=="Windows_NT" setlocal
 
-@rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
-set DEFAULT_JVM_OPTS=
-
 set DIRNAME=%~dp0
 if "%DIRNAME%" == "" set DIRNAME=.
 set APP_BASE_NAME=%~n0
 set APP_HOME=%DIRNAME%
 
+@rem Resolve any "." and ".." in APP_HOME to make it shorter.
+for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
+
+@rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
+
 @rem Find java.exe
 if defined JAVA_HOME goto findJavaFromJavaHome
 
 set JAVA_EXE=java.exe
 %JAVA_EXE% -version >NUL 2>&1
-if "%ERRORLEVEL%" == "0" goto init
+if "%ERRORLEVEL%" == "0" goto execute
 
 echo.
 echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
@@ -35,7 +54,7 @@ goto fail
 set JAVA_HOME=%JAVA_HOME:"=%
 set JAVA_EXE=%JAVA_HOME%/bin/java.exe
 
-if exist "%JAVA_EXE%" goto init
+if exist "%JAVA_EXE%" goto execute
 
 echo.
 echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
@@ -45,34 +64,14 @@ echo location of your Java installation.
 
 goto fail
 
-:init
-@rem Get command-line arguments, handling Windowz variants
-
-if not "%OS%" == "Windows_NT" goto win9xME_args
-if "%@eval[2+2]" == "4" goto 4NT_args
-
-:win9xME_args
-@rem Slurp the command line arguments.
-set CMD_LINE_ARGS=
-set _SKIP=2
-
-:win9xME_args_slurp
-if "x%~1" == "x" goto execute
-
-set CMD_LINE_ARGS=%*
-goto execute
-
-:4NT_args
-@rem Get arguments from the 4NT Shell from JP Software
-set CMD_LINE_ARGS=%$
-
 :execute
 @rem Setup the command line
 
 set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
 
+
 @rem Execute Gradle
-"%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -classpath "%CLASSPATH%" org.gradle.wrapper.GradleWrapperMain %CMD_LINE_ARGS%
+"%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -classpath "%CLASSPATH%" org.gradle.wrapper.GradleWrapperMain %*
 
 :end
 @rem End local scope for the variables with windows NT shell
diff --git a/Android/settings.gradle b/Android/settings.gradle
index b11319c8..e7b4def4 100644
--- a/Android/settings.gradle
+++ b/Android/settings.gradle
@@ -1 +1 @@
-include ':app', ':tun2socks'
+include ':app'
diff --git a/Android/tun2socks/build.gradle b/Android/tun2socks/build.gradle
deleted file mode 100644
index 26987183..00000000
--- a/Android/tun2socks/build.gradle
+++ /dev/null
@@ -1,78 +0,0 @@
-// We use Android library plugin to get the Android SDK path.
-plugins {
-    id('com.android.library')
-}
-
-android {
-    compileSdkVersion ANDROID_COMPILE_SDK_VERSION as int
-    defaultConfig {
-        minSdkVersion ANDROID_MIN_SDK_VERSION as int
-    }
-}
-
-configurations {
-    aarBinary {
-        canBeConsumed = true
-        canBeResolved = false
-    }
-}
-
-def goBuildDir = file("${buildDir}/go")
-def outputAAR = file("${buildDir}/tun2socks.aar")
-
-def srcDir = "${rootDir}/tun2socks/intra"
-def srcPackages = [srcDir,
-                   "${srcDir}/android",
-                   "${srcDir}/doh",
-                   "${srcDir}/split",
-                   "${srcDir}/protect"]
-
-// Make sure that the go build directory exists.
-task ensureBuildDir() {
-    doLast {
-        goBuildDir.mkdirs()
-    }
-}
-
-// Install `gomobile` and `gobind` to the build directory, so that the user
-// does not need to install them on their system or call `gomobile init`.
-task ensureGoMobile(type: Exec, dependsOn: ensureBuildDir) {
-    // Define outputs so this task will only be executed when they don't exist
-    outputs.file("${goBuildDir}/gomobile")
-    outputs.file("${goBuildDir}/gobind")
-
-    commandLine('go', 'build',
-                '-o', goBuildDir,
-                'golang.org/x/mobile/cmd/gomobile',
-                'golang.org/x/mobile/cmd/gobind')
-}
-
-// Invoke `gomobile bind` to build from `srcPackages` to `outputAAR`.
-// `gomobile` needs the `ANDROID_HOME` environment variable to be set, and the
-// parent directory of `gobind` must be in the `PATH` as well.
-task gobind(type: Exec, dependsOn: ensureGoMobile) {
-    // Define inputs and outputs so Gradle will enable incremental builds
-    inputs.dir(srcDir)
-    outputs.file(outputAAR)
-
-    workingDir goBuildDir
-    environment 'ANDROID_HOME', android.sdkDirectory
-    environment 'PATH', goBuildDir.getPath() +
-                        System.getProperty('path.separator') +
-                        System.getenv('PATH')
-
-    commandLine("${goBuildDir}/gomobile", 'bind',
-                '-ldflags=-s -w',
-                '-target=android',
-                "-androidapi=${android.defaultConfig.minSdk}",
-                '-o', outputAAR,
-                *srcPackages)
-}
-
-// AAR file that can be consumed by other projects. For example:
-//   implementation project(path: ':tun2socks', configuration: 'aarBinary')
-artifacts {
-    aarBinary(outputAAR) {
-        builtBy(gobind)
-    }
-}
diff --git a/Android/tun2socks/src/main/AndroidManifest.xml b/Android/tun2socks/src/main/AndroidManifest.xml
deleted file mode 100644
index 788b4795..00000000
--- a/Android/tun2socks/src/main/AndroidManifest.xml
+++ /dev/null
@@ -1,3 +0,0 @@
-<?xml version="1.0" encoding="utf-8"?>
-<manifest package="app.intra.tun2socks">
-</manifest>