diff --git a/bpf_progs/clatd.h b/bpf_progs/clatd.h
new file mode 100644
index 0000000..b5f1cdc
--- /dev/null
+++ b/bpf_progs/clatd.h
@@ -0,0 +1,60 @@
+/*
+ * 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.
+ */
+
+#pragma once
+
+#include <linux/in.h>
+#include <linux/in6.h>
+
+#include <stdbool.h>
+#include <stdint.h>
+
+// This header file is shared by eBPF kernel programs (C) and netd (C++) and
+// some of the maps are also accessed directly from Java mainline module code.
+//
+// Hence: explicitly pad all relevant structures and assert that their size
+// is the sum of the sizes of their fields.
+#define STRUCT_SIZE(name, size) _Static_assert(sizeof(name) == (size), "Incorrect struct size.")
+
+typedef struct {
+    uint32_t iif;            // The input interface index
+    struct in6_addr pfx96;   // The source /96 nat64 prefix, bottom 32 bits must be 0
+    struct in6_addr local6;  // The full 128-bits of the destination IPv6 address
+} ClatIngress6Key;
+STRUCT_SIZE(ClatIngress6Key, 4 + 2 * 16);  // 36
+
+typedef struct {
+    uint32_t oif;           // The output interface to redirect to (0 means don't redirect)
+    struct in_addr local4;  // The destination IPv4 address
+} ClatIngress6Value;
+STRUCT_SIZE(ClatIngress6Value, 4 + 4);  // 8
+
+typedef struct {
+    uint32_t iif;           // The input interface index
+    struct in_addr local4;  // The source IPv4 address
+} ClatEgress4Key;
+STRUCT_SIZE(ClatEgress4Key, 4 + 4);  // 8
+
+typedef struct {
+    uint32_t oif;            // The output interface to redirect to
+    struct in6_addr local6;  // The full 128-bits of the source IPv6 address
+    struct in6_addr pfx96;   // The destination /96 nat64 prefix, bottom 32 bits must be 0
+    bool oifIsEthernet;      // Whether the output interface requires ethernet header
+    uint8_t pad[3];
+} ClatEgress4Value;
+STRUCT_SIZE(ClatEgress4Value, 4 + 2 * 16 + 1 + 3);  // 40
+
+#undef STRUCT_SIZE