diff --git a/staticlibs/native/ip_checksum/Android.bp b/staticlibs/native/ip_checksum/Android.bp
new file mode 100644
index 0000000..d7e195d
--- /dev/null
+++ b/staticlibs/native/ip_checksum/Android.bp
@@ -0,0 +1,40 @@
+// Copyright (C) 2021 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 {
+    default_applicable_licenses: ["Android-Apache-2.0"],
+}
+
+cc_library_static {
+    name: "libip_checksum",
+
+    srcs: [
+        "checksum.c",
+    ],
+
+    cflags: [
+        "-Wall",
+        "-Werror",
+    ],
+
+    export_include_dirs: ["."],
+
+    // Needed because libnetutils depends on libip_checksum, and libnetutils has
+    // vendor_available = true. Making this library vendor_available does not create any maintenance
+    // burden or version skew issues because this library is only static, not dynamic, and thus is
+    // not installed on the device.
+    //
+    // TODO: delete libnetutils from the VNDK in T, and remove this.
+    vendor_available: true,
+}
diff --git a/staticlibs/native/ip_checksum/checksum.c b/staticlibs/native/ip_checksum/checksum.c
new file mode 100644
index 0000000..04217a7
--- /dev/null
+++ b/staticlibs/native/ip_checksum/checksum.c
@@ -0,0 +1,145 @@
+/*
+ * Copyright 2011 Daniel Drown
+ *
+ * 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.
+ *
+ * checksum.c - ipv4/ipv6 checksum calculation
+ */
+#include <netinet/icmp6.h>
+#include <netinet/in.h>
+#include <netinet/ip.h>
+#include <netinet/ip6.h>
+#include <netinet/ip_icmp.h>
+#include <netinet/tcp.h>
+#include <netinet/udp.h>
+
+#include "checksum.h"
+
+/* function: ip_checksum_add
+ * adds data to a checksum. only known to work on little-endian hosts
+ * current - the current checksum (or 0 to start a new checksum)
+ *   data        - the data to add to the checksum
+ *   len         - length of data
+ */
+uint32_t ip_checksum_add(uint32_t current, const void* data, int len) {
+    uint32_t checksum = current;
+    int left = len;
+    const uint16_t* data_16 = data;
+
+    while (left > 1) {
+        checksum += *data_16;
+        data_16++;
+        left -= 2;
+    }
+    if (left) {
+        checksum += *(uint8_t*)data_16;
+    }
+
+    return checksum;
+}
+
+/* function: ip_checksum_fold
+ * folds a 32-bit partial checksum into 16 bits
+ *   temp_sum - sum from ip_checksum_add
+ *   returns: the folded checksum in network byte order
+ */
+uint16_t ip_checksum_fold(uint32_t temp_sum) {
+    while (temp_sum > 0xffff) {
+        temp_sum = (temp_sum >> 16) + (temp_sum & 0xFFFF);
+    }
+    return temp_sum;
+}
+
+/* function: ip_checksum_finish
+ * folds and closes the checksum
+ *   temp_sum - sum from ip_checksum_add
+ *   returns: a header checksum value in network byte order
+ */
+uint16_t ip_checksum_finish(uint32_t temp_sum) {
+    return ~ip_checksum_fold(temp_sum);
+}
+
+/* function: ip_checksum
+ * combined ip_checksum_add and ip_checksum_finish
+ *   data - data to checksum
+ *   len  - length of data
+ */
+uint16_t ip_checksum(const void* data, int len) {
+    // TODO: consider starting from 0xffff so the checksum of a buffer entirely consisting of zeros
+    // is correctly calculated as 0.
+    uint32_t temp_sum;
+
+    temp_sum = ip_checksum_add(0, data, len);
+    return ip_checksum_finish(temp_sum);
+}
+
+/* function: ipv6_pseudo_header_checksum
+ * calculate the pseudo header checksum for use in tcp/udp/icmp headers
+ *   ip6      - the ipv6 header
+ *   len      - the transport length (transport header + payload)
+ *   protocol - the transport layer protocol, can be different from ip6->ip6_nxt for fragments
+ */
+uint32_t ipv6_pseudo_header_checksum(const struct ip6_hdr* ip6, uint32_t len, uint8_t protocol) {
+    uint32_t checksum_len = htonl(len);
+    uint32_t checksum_next = htonl(protocol);
+
+    uint32_t current = 0;
+
+    current = ip_checksum_add(current, &(ip6->ip6_src), sizeof(struct in6_addr));
+    current = ip_checksum_add(current, &(ip6->ip6_dst), sizeof(struct in6_addr));
+    current = ip_checksum_add(current, &checksum_len, sizeof(checksum_len));
+    current = ip_checksum_add(current, &checksum_next, sizeof(checksum_next));
+
+    return current;
+}
+
+/* function: ipv4_pseudo_header_checksum
+ * calculate the pseudo header checksum for use in tcp/udp headers
+ *   ip      - the ipv4 header
+ *   len     - the transport length (transport header + payload)
+ */
+uint32_t ipv4_pseudo_header_checksum(const struct iphdr* ip, uint16_t len) {
+    uint16_t temp_protocol, temp_length;
+
+    temp_protocol = htons(ip->protocol);
+    temp_length = htons(len);
+
+    uint32_t current = 0;
+
+    current = ip_checksum_add(current, &(ip->saddr), sizeof(uint32_t));
+    current = ip_checksum_add(current, &(ip->daddr), sizeof(uint32_t));
+    current = ip_checksum_add(current, &temp_protocol, sizeof(uint16_t));
+    current = ip_checksum_add(current, &temp_length, sizeof(uint16_t));
+
+    return current;
+}
+
+/* function: ip_checksum_adjust
+ * calculates a new checksum given a previous checksum and the old and new pseudo-header checksums
+ *   checksum    - the header checksum in the original packet in network byte order
+ *   old_hdr_sum - the pseudo-header checksum of the original packet
+ *   new_hdr_sum - the pseudo-header checksum of the translated packet
+ *   returns: the new header checksum in network byte order
+ */
+uint16_t ip_checksum_adjust(uint16_t checksum, uint32_t old_hdr_sum, uint32_t new_hdr_sum) {
+    // Algorithm suggested in RFC 1624.
+    // http://tools.ietf.org/html/rfc1624#section-3
+    checksum = ~checksum;
+    uint16_t folded_sum = ip_checksum_fold(checksum + new_hdr_sum);
+    uint16_t folded_old = ip_checksum_fold(old_hdr_sum);
+    if (folded_sum > folded_old) {
+        return ~(folded_sum - folded_old);
+    } else {
+        return ~(folded_sum - folded_old - 1);  // end-around borrow
+    }
+}
diff --git a/staticlibs/native/ip_checksum/checksum.h b/staticlibs/native/ip_checksum/checksum.h
new file mode 100644
index 0000000..868217c
--- /dev/null
+++ b/staticlibs/native/ip_checksum/checksum.h
@@ -0,0 +1,34 @@
+/*
+ * Copyright 2011 Daniel Drown
+ *
+ * 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.
+ *
+ * checksum.h - checksum functions
+ */
+#ifndef __CHECKSUM_H__
+#define __CHECKSUM_H__
+
+#include <netinet/ip.h>
+#include <netinet/ip6.h>
+#include <stdint.h>
+
+uint32_t ip_checksum_add(uint32_t current, const void* data, int len);
+uint16_t ip_checksum_finish(uint32_t temp_sum);
+uint16_t ip_checksum(const void* data, int len);
+
+uint32_t ipv6_pseudo_header_checksum(const struct ip6_hdr* ip6, uint32_t len, uint8_t protocol);
+uint32_t ipv4_pseudo_header_checksum(const struct iphdr* ip, uint16_t len);
+
+uint16_t ip_checksum_adjust(uint16_t checksum, uint32_t old_hdr_sum, uint32_t new_hdr_sum);
+
+#endif /* __CHECKSUM_H__ */