diff --git a/tools/Android.bp b/tools/Android.bp
new file mode 100644
index 0000000..1fa93bb
--- /dev/null
+++ b/tools/Android.bp
@@ -0,0 +1,91 @@
+//
+// Copyright (C) 2022 The Android Open Source Project
+//
+// 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
+//
+//      http://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.
+//
+
+package {
+    // See: http://go/android-license-faq
+    default_applicable_licenses: ["Android-Apache-2.0"],
+}
+
+// Build tool used to generate jarjar rules for all classes in a jar, except those that are
+// API, UnsupportedAppUsage or otherwise excluded.
+python_binary_host {
+    name: "jarjar-rules-generator",
+    srcs: [
+        "gen_jarjar.py",
+    ],
+    main: "gen_jarjar.py",
+    version: {
+        py2: {
+            enabled: false,
+        },
+        py3: {
+            enabled: true,
+        },
+    },
+    visibility: ["//packages/modules/Connectivity:__subpackages__"],
+}
+
+genrule_defaults {
+    name: "jarjar-rules-combine-defaults",
+    // Concat files with a line break in the middle
+    cmd: "for src in $(in); do cat $${src}; echo; done > $(out)",
+    defaults_visibility: ["//packages/modules/Connectivity:__subpackages__"],
+}
+
+java_library {
+    name: "jarjar-rules-generator-testjavalib",
+    srcs: ["testdata/java/**/*.java"],
+    visibility: ["//visibility:private"],
+}
+
+// TODO(b/233723405) - Remove this workaround.
+// Temporary work around of b/233723405. Using the module_lib stub directly
+// in the test causes it to sometimes get the dex jar and sometimes get the
+// classes jar due to b/233111644. Statically including it here instead
+// ensures that it will always get the classes jar.
+java_library {
+    name: "framework-connectivity.stubs.module_lib-for-test",
+    visibility: ["//visibility:private"],
+    static_libs: [
+        "framework-connectivity.stubs.module_lib",
+    ],
+    // Not strictly necessary but specified as this MUST not have generate
+    // a dex jar as that will break the tests.
+    compile_dex: false,
+}
+
+python_test_host {
+    name: "jarjar-rules-generator-test",
+    srcs: [
+        "gen_jarjar.py",
+        "gen_jarjar_test.py",
+    ],
+    data: [
+        "testdata/test-jarjar-excludes.txt",
+        "testdata/test-unsupportedappusage.txt",
+        ":framework-connectivity.stubs.module_lib-for-test",
+        ":jarjar-rules-generator-testjavalib",
+    ],
+    main: "gen_jarjar_test.py",
+    version: {
+        py2: {
+            enabled: false,
+        },
+        py3: {
+            enabled: true,
+        },
+    },
+}
diff --git a/tools/gen_jarjar.py b/tools/gen_jarjar.py
new file mode 100755
index 0000000..4c2cf54
--- /dev/null
+++ b/tools/gen_jarjar.py
@@ -0,0 +1,133 @@
+#
+# Copyright (C) 2022 The Android Open Source Project
+#
+# 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
+#
+#      http://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.
+
+""" This script generates jarjar rule files to add a jarjar prefix to all classes, except those
+that are API, unsupported API or otherwise excluded."""
+
+import argparse
+import io
+import re
+import subprocess
+from xml import sax
+from xml.sax.handler import ContentHandler
+from zipfile import ZipFile
+
+
+def parse_arguments(argv):
+    parser = argparse.ArgumentParser()
+    parser.add_argument(
+        '--jars', nargs='+',
+        help='Path to pre-jarjar JAR. Can be followed by multiple space-separated paths.')
+    parser.add_argument(
+        '--prefix', required=True,
+        help='Package prefix to use for jarjared classes, '
+             'for example "com.android.connectivity" (does not end with a dot).')
+    parser.add_argument(
+        '--output', required=True, help='Path to output jarjar rules file.')
+    parser.add_argument(
+        '--apistubs', nargs='*', default=[],
+        help='Path to API stubs jar. Classes that are API will not be jarjared. Can be followed by '
+             'multiple space-separated paths.')
+    parser.add_argument(
+        '--unsupportedapi', nargs='*', default=[],
+        help='Path to UnsupportedAppUsage hidden API .txt lists. '
+             'Classes that have UnsupportedAppUsage API will not be jarjared. Can be followed by '
+             'multiple space-separated paths.')
+    parser.add_argument(
+        '--excludes', nargs='*', default=[],
+        help='Path to files listing classes that should not be jarjared. Can be followed by '
+             'multiple space-separated paths. '
+             'Each file should contain one full-match regex per line. Empty lines or lines '
+             'starting with "#" are ignored.')
+    return parser.parse_args(argv)
+
+
+def _list_toplevel_jar_classes(jar):
+    """List all classes in a .class .jar file that are not inner classes."""
+    return {_get_toplevel_class(c) for c in _list_jar_classes(jar)}
+
+def _list_jar_classes(jar):
+    with ZipFile(jar, 'r') as zip:
+        files = zip.namelist()
+        assert 'classes.dex' not in files, f'Jar file {jar} is dexed, ' \
+                                           'expected an intermediate zip of .class files'
+        class_len = len('.class')
+        return [f.replace('/', '.')[:-class_len] for f in files
+                if f.endswith('.class') and not f.endswith('/package-info.class')]
+
+
+def _list_hiddenapi_classes(txt_file):
+    out = set()
+    with open(txt_file, 'r') as f:
+        for line in f:
+            if not line.strip():
+                continue
+            assert line.startswith('L') and ';' in line, f'Class name not recognized: {line}'
+            clazz = line.replace('/', '.').split(';')[0][1:]
+            out.add(_get_toplevel_class(clazz))
+    return out
+
+
+def _get_toplevel_class(clazz):
+    """Return the name of the toplevel (not an inner class) enclosing class of the given class."""
+    if '$' not in clazz:
+        return clazz
+    return clazz.split('$')[0]
+
+
+def _get_excludes(path):
+    out = []
+    with open(path, 'r') as f:
+        for line in f:
+            stripped = line.strip()
+            if not stripped or stripped.startswith('#'):
+                continue
+            out.append(re.compile(stripped))
+    return out
+
+
+def make_jarjar_rules(args):
+    excluded_classes = set()
+    for apistubs_file in args.apistubs:
+        excluded_classes.update(_list_toplevel_jar_classes(apistubs_file))
+
+    for unsupportedapi_file in args.unsupportedapi:
+        excluded_classes.update(_list_hiddenapi_classes(unsupportedapi_file))
+
+    exclude_regexes = []
+    for exclude_file in args.excludes:
+        exclude_regexes.extend(_get_excludes(exclude_file))
+
+    with open(args.output, 'w') as outfile:
+        for jar in args.jars:
+            jar_classes = _list_jar_classes(jar)
+            jar_classes.sort()
+            for clazz in jar_classes:
+                if (_get_toplevel_class(clazz) not in excluded_classes and
+                        not any(r.fullmatch(clazz) for r in exclude_regexes)):
+                    outfile.write(f'rule {clazz} {args.prefix}.@0\n')
+                    # Also include jarjar rules for unit tests of the class, so the package matches
+                    outfile.write(f'rule {clazz}Test {args.prefix}.@0\n')
+                    outfile.write(f'rule {clazz}Test$* {args.prefix}.@0\n')
+
+
+def _main():
+    # Pass in None to use argv
+    args = parse_arguments(None)
+    make_jarjar_rules(args)
+
+
+if __name__ == '__main__':
+    _main()
diff --git a/tools/gen_jarjar_test.py b/tools/gen_jarjar_test.py
new file mode 100644
index 0000000..8d8e82b
--- /dev/null
+++ b/tools/gen_jarjar_test.py
@@ -0,0 +1,57 @@
+#  Copyright (C) 2022 The Android Open Source Project
+#
+#  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
+#
+#       http://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.
+#
+#  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
+#
+#       http://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.
+
+import gen_jarjar
+import unittest
+
+
+class TestGenJarjar(unittest.TestCase):
+    def test_gen_rules(self):
+        args = gen_jarjar.parse_arguments([
+            "--jars", "jarjar-rules-generator-testjavalib.jar",
+            "--prefix", "jarjar.prefix",
+            "--output", "test-output-rules.txt",
+            "--apistubs", "framework-connectivity.stubs.module_lib.jar",
+            "--unsupportedapi", "testdata/test-unsupportedappusage.txt",
+            "--excludes", "testdata/test-jarjar-excludes.txt",
+        ])
+        gen_jarjar.make_jarjar_rules(args)
+
+        with open(args.output) as out:
+            lines = out.readlines()
+
+        self.assertListEqual([
+            'rule test.utils.TestUtilClass jarjar.prefix.@0\n',
+            'rule test.utils.TestUtilClassTest jarjar.prefix.@0\n',
+            'rule test.utils.TestUtilClassTest$* jarjar.prefix.@0\n',
+            'rule test.utils.TestUtilClass$TestInnerClass jarjar.prefix.@0\n',
+            'rule test.utils.TestUtilClass$TestInnerClassTest jarjar.prefix.@0\n',
+            'rule test.utils.TestUtilClass$TestInnerClassTest$* jarjar.prefix.@0\n'], lines)
+
+
+if __name__ == '__main__':
+    # Need verbosity=2 for the test results parser to find results
+    unittest.main(verbosity=2)
diff --git a/tools/testdata/java/android/net/LinkProperties.java b/tools/testdata/java/android/net/LinkProperties.java
new file mode 100644
index 0000000..bdca377
--- /dev/null
+++ b/tools/testdata/java/android/net/LinkProperties.java
@@ -0,0 +1,23 @@
+/*
+ * Copyright (C) 2022 The Android Open Source Project
+ *
+ * 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
+ *
+ *      http://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.
+ */
+
+package android.net;
+
+/**
+ * Test class with a name matching a public API.
+ */
+public class LinkProperties {
+}
diff --git a/tools/testdata/java/test/jarjarexcluded/JarjarExcludedClass.java b/tools/testdata/java/test/jarjarexcluded/JarjarExcludedClass.java
new file mode 100644
index 0000000..7e3bee1
--- /dev/null
+++ b/tools/testdata/java/test/jarjarexcluded/JarjarExcludedClass.java
@@ -0,0 +1,23 @@
+/*
+ * Copyright (C) 2022 The Android Open Source Project
+ *
+ * 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
+ *
+ *      http://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.
+ */
+
+package test.jarjarexcluded;
+
+/**
+ * Test class that is excluded from jarjar.
+ */
+public class JarjarExcludedClass {
+}
diff --git a/tools/testdata/java/test/unsupportedappusage/TestUnsupportedAppUsageClass.java b/tools/testdata/java/test/unsupportedappusage/TestUnsupportedAppUsageClass.java
new file mode 100644
index 0000000..9d32296
--- /dev/null
+++ b/tools/testdata/java/test/unsupportedappusage/TestUnsupportedAppUsageClass.java
@@ -0,0 +1,21 @@
+/*
+ * Copyright (C) 2022 The Android Open Source Project
+ *
+ * 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
+ *
+ *      http://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.
+ */
+
+package test.unsupportedappusage;
+
+public class TestUnsupportedAppUsageClass {
+    public void testMethod() {}
+}
diff --git a/tools/testdata/java/test/utils/TestUtilClass.java b/tools/testdata/java/test/utils/TestUtilClass.java
new file mode 100644
index 0000000..2162e45
--- /dev/null
+++ b/tools/testdata/java/test/utils/TestUtilClass.java
@@ -0,0 +1,24 @@
+/*
+ * Copyright (C) 2022 The Android Open Source Project
+ *
+ * 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
+ *
+ *      http://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.
+ */
+
+package test.utils;
+
+/**
+ * Sample class to test jarjar rules.
+ */
+public class TestUtilClass {
+    public static class TestInnerClass {}
+}
diff --git a/tools/testdata/test-jarjar-excludes.txt b/tools/testdata/test-jarjar-excludes.txt
new file mode 100644
index 0000000..35d97a2
--- /dev/null
+++ b/tools/testdata/test-jarjar-excludes.txt
@@ -0,0 +1,3 @@
+# Test file for excluded classes
+test\.jarj.rexcluded\.JarjarExcludedCla.s
+test\.jarjarexcluded\.JarjarExcludedClass\$TestInnerCl.ss
diff --git a/tools/testdata/test-unsupportedappusage.txt b/tools/testdata/test-unsupportedappusage.txt
new file mode 100644
index 0000000..331eff9
--- /dev/null
+++ b/tools/testdata/test-unsupportedappusage.txt
@@ -0,0 +1 @@
+Ltest/unsupportedappusage/TestUnsupportedAppUsageClass;->testMethod()V
\ No newline at end of file