Add struct ClatIngress6Key

This is a preparation for moving clat map access to java BpfMap class

Test: make net-utils-device-common-bpf
Change-Id: I869a9afa45a5257be028dae5b9d627f891222c80
diff --git a/common/device/com/android/net/module/util/bpf/ClatIngress6Key.java b/common/device/com/android/net/module/util/bpf/ClatIngress6Key.java
new file mode 100644
index 0000000..1e2f4e0
--- /dev/null
+++ b/common/device/com/android/net/module/util/bpf/ClatIngress6Key.java
@@ -0,0 +1,41 @@
+/*
+ * 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 com.android.net.module.util.bpf;
+
+import com.android.net.module.util.Struct;
+import com.android.net.module.util.Struct.Field;
+import com.android.net.module.util.Struct.Type;
+
+import java.net.Inet6Address;
+
+/** Key type for clat ingress IPv6 maps. */
+public class ClatIngress6Key extends Struct {
+    @Field(order = 0, type = Type.U32)
+    public final long iif; // The input interface index
+
+    @Field(order = 1, type = Type.Ipv6Address)
+    public final Inet6Address pfx96; // The source /96 nat64 prefix, bottom 32 bits must be 0
+
+    @Field(order = 2, type = Type.Ipv6Address)
+    public final Inet6Address local6; // The full 128-bits of the destination IPv6 address
+
+    public ClatIngress6Key(final long iif, final Inet6Address pfx96, final Inet6Address local6) {
+        this.iif = iif;
+        this.pfx96 = pfx96;
+        this.local6 = local6;
+    }
+}