Add API Surface for creating IpSec Transforms

This CL adds an API to set up an IPSec Security Association
and Security Policy to perform Transport-Mode and Tunnel-Mode encapuslation
of IP Packets.

Bug: 30984788
Bug: 34811752
Test: 34812052, 34811227
Change-Id: Ic9f63c7bb366302a24baa3e1b79020210910ac0a

9 files changed, 1455 insertions, 0 deletions

diff --git a/api/current.txt b/api/current.txt
index 5555d1fee777..ad3284500280 100644
--- a/api/current.txt
+++ b/api/current.txt
@@ -8188,6 +8188,7 @@ package android.content {
     field public static final java.lang.String HARDWARE_PROPERTIES_SERVICE = "hardware_properties";
     field public static final java.lang.String INPUT_METHOD_SERVICE = "input_method";
     field public static final java.lang.String INPUT_SERVICE = "input";
+    field public static final java.lang.String IPSEC_SERVICE = "ipsec";
     field public static final java.lang.String JOB_SCHEDULER_SERVICE = "jobscheduler";
     field public static final java.lang.String KEYGUARD_SERVICE = "keyguard";
     field public static final java.lang.String LAUNCHER_APPS_SERVICE = "launcherapps";
@@ -23724,6 +23725,68 @@ package android.net {
     field public static final android.os.Parcelable.Creator<android.net.IpPrefix> CREATOR;
   }
 
+  public final class IpSecAlgorithm implements android.os.Parcelable {
+    ctor public IpSecAlgorithm(java.lang.String, byte[]);
+    ctor public IpSecAlgorithm(java.lang.String, byte[], int);
+    method public int describeContents();
+    method public byte[] getKey();
+    method public java.lang.String getName();
+    method public int getTruncationLengthBits();
+    method public void writeToParcel(android.os.Parcel, int);
+    field public static final java.lang.String ALGO_AUTH_HMAC_MD5 = "hmac(md5)";
+    field public static final java.lang.String ALGO_AUTH_HMAC_SHA1 = "hmac(sha1)";
+    field public static final java.lang.String ALGO_AUTH_HMAC_SHA256 = "hmac(sha256)";
+    field public static final java.lang.String ALGO_AUTH_HMAC_SHA384 = "hmac(sha384)";
+    field public static final java.lang.String ALGO_AUTH_HMAC_SHA512 = "hmac(sha512)";
+    field public static final java.lang.String ALGO_CRYPT_AES_CBC = "cbc(aes)";
+    field public static final android.os.Parcelable.Creator<android.net.IpSecAlgorithm> CREATOR;
+  }
+
+  public final class IpSecManager {
+    method public void applyTransportModeTransform(java.net.Socket, android.net.IpSecTransform) throws java.io.IOException;
+    method public void applyTransportModeTransform(java.net.DatagramSocket, android.net.IpSecTransform) throws java.io.IOException;
+    method public android.net.IpSecManager.UdpEncapsulationSocket openUdpEncapsulationSocket(int) throws java.io.IOException, android.net.IpSecManager.ResourceUnavailableException;
+    method public android.net.IpSecManager.UdpEncapsulationSocket openUdpEncapsulationSocket() throws java.io.IOException, android.net.IpSecManager.ResourceUnavailableException;
+    method public void removeTransportModeTransform(java.net.Socket, android.net.IpSecTransform);
+    method public void removeTransportModeTransform(java.net.DatagramSocket, android.net.IpSecTransform);
+    method public android.net.IpSecManager.SecurityParameterIndex reserveSecurityParameterIndex(java.net.InetAddress, int) throws android.net.IpSecManager.ResourceUnavailableException, android.net.IpSecManager.SpiUnavailableException;
+    field public static final int INVALID_SECURITY_PARAMETER_INDEX = 0; // 0x0
+  }
+
+  public static final class IpSecManager.ResourceUnavailableException extends android.util.AndroidException {
+  }
+
+  public static final class IpSecManager.SecurityParameterIndex implements java.lang.AutoCloseable {
+    method public void close();
+    method public int getSpi();
+  }
+
+  public static final class IpSecManager.SpiUnavailableException extends android.util.AndroidException {
+    method public int getSpi();
+  }
+
+  public static final class IpSecManager.UdpEncapsulationSocket implements java.lang.AutoCloseable {
+    method public void close();
+    method public int getPort();
+    method public java.io.FileDescriptor getSocket();
+  }
+
+  public final class IpSecTransform implements java.lang.AutoCloseable {
+    method public void close();
+    field public static final int DIRECTION_IN = 0; // 0x0
+    field public static final int DIRECTION_OUT = 1; // 0x1
+  }
+
+  public static class IpSecTransform.Builder {
+    ctor public IpSecTransform.Builder(android.content.Context);
+    method public android.net.IpSecTransform buildTransportModeTransform(java.net.InetAddress) throws java.io.IOException, android.net.IpSecManager.ResourceUnavailableException, android.net.IpSecManager.SpiUnavailableException;
+    method public android.net.IpSecTransform.Builder setAuthentication(int, android.net.IpSecAlgorithm);
+    method public android.net.IpSecTransform.Builder setEncryption(int, android.net.IpSecAlgorithm);
+    method public android.net.IpSecTransform.Builder setIpv4Encapsulation(android.net.IpSecManager.UdpEncapsulationSocket, int);
+    method public android.net.IpSecTransform.Builder setSpi(int, int);
+    method public android.net.IpSecTransform.Builder setSpi(int, android.net.IpSecManager.SecurityParameterIndex);
+  }
+
   public class LinkAddress implements android.os.Parcelable {
     method public int describeContents();
     method public java.net.InetAddress getAddress();
diff --git a/api/system-current.txt b/api/system-current.txt
index 701c86ffef56..7e1e06c0fc85 100644
--- a/api/system-current.txt
+++ b/api/system-current.txt
@@ -8522,6 +8522,7 @@ package android.content {
     field public static final java.lang.String HDMI_CONTROL_SERVICE = "hdmi_control";
     field public static final java.lang.String INPUT_METHOD_SERVICE = "input_method";
     field public static final java.lang.String INPUT_SERVICE = "input";
+    field public static final java.lang.String IPSEC_SERVICE = "ipsec";
     field public static final java.lang.String JOB_SCHEDULER_SERVICE = "jobscheduler";
     field public static final java.lang.String KEYGUARD_SERVICE = "keyguard";
     field public static final java.lang.String LAUNCHER_APPS_SERVICE = "launcherapps";
@@ -25561,6 +25562,73 @@ package android.net {
     field public static final android.os.Parcelable.Creator<android.net.IpPrefix> CREATOR;
   }
 
+  public final class IpSecAlgorithm implements android.os.Parcelable {
+    ctor public IpSecAlgorithm(java.lang.String, byte[]);
+    ctor public IpSecAlgorithm(java.lang.String, byte[], int);
+    method public int describeContents();
+    method public byte[] getKey();
+    method public java.lang.String getName();
+    method public int getTruncationLengthBits();
+    method public void writeToParcel(android.os.Parcel, int);
+    field public static final java.lang.String ALGO_AUTH_HMAC_MD5 = "hmac(md5)";
+    field public static final java.lang.String ALGO_AUTH_HMAC_SHA1 = "hmac(sha1)";
+    field public static final java.lang.String ALGO_AUTH_HMAC_SHA256 = "hmac(sha256)";
+    field public static final java.lang.String ALGO_AUTH_HMAC_SHA384 = "hmac(sha384)";
+    field public static final java.lang.String ALGO_AUTH_HMAC_SHA512 = "hmac(sha512)";
+    field public static final java.lang.String ALGO_CRYPT_AES_CBC = "cbc(aes)";
+    field public static final android.os.Parcelable.Creator<android.net.IpSecAlgorithm> CREATOR;
+  }
+
+  public final class IpSecManager {
+    method public void applyTransportModeTransform(java.net.Socket, android.net.IpSecTransform) throws java.io.IOException;
+    method public void applyTransportModeTransform(java.net.DatagramSocket, android.net.IpSecTransform) throws java.io.IOException;
+    method public void applyTunnelModeTransform(android.net.Network, android.net.IpSecTransform);
+    method public android.net.IpSecManager.UdpEncapsulationSocket openUdpEncapsulationSocket(int) throws java.io.IOException, android.net.IpSecManager.ResourceUnavailableException;
+    method public android.net.IpSecManager.UdpEncapsulationSocket openUdpEncapsulationSocket() throws java.io.IOException, android.net.IpSecManager.ResourceUnavailableException;
+    method public void removeTransportModeTransform(java.net.Socket, android.net.IpSecTransform);
+    method public void removeTransportModeTransform(java.net.DatagramSocket, android.net.IpSecTransform);
+    method public void removeTunnelModeTransform(android.net.Network, android.net.IpSecTransform);
+    method public android.net.IpSecManager.SecurityParameterIndex reserveSecurityParameterIndex(java.net.InetAddress, int) throws android.net.IpSecManager.ResourceUnavailableException, android.net.IpSecManager.SpiUnavailableException;
+    field public static final int INVALID_SECURITY_PARAMETER_INDEX = 0; // 0x0
+  }
+
+  public static final class IpSecManager.ResourceUnavailableException extends android.util.AndroidException {
+  }
+
+  public static final class IpSecManager.SecurityParameterIndex implements java.lang.AutoCloseable {
+    method public void close();
+    method public int getSpi();
+  }
+
+  public static final class IpSecManager.SpiUnavailableException extends android.util.AndroidException {
+    method public int getSpi();
+  }
+
+  public static final class IpSecManager.UdpEncapsulationSocket implements java.lang.AutoCloseable {
+    method public void close();
+    method public int getPort();
+    method public java.io.FileDescriptor getSocket();
+  }
+
+  public final class IpSecTransform implements java.lang.AutoCloseable {
+    method public void close();
+    field public static final int DIRECTION_IN = 0; // 0x0
+    field public static final int DIRECTION_OUT = 1; // 0x1
+  }
+
+  public static class IpSecTransform.Builder {
+    ctor public IpSecTransform.Builder(android.content.Context);
+    method public android.net.IpSecTransform buildTransportModeTransform(java.net.InetAddress) throws java.io.IOException, android.net.IpSecManager.ResourceUnavailableException, android.net.IpSecManager.SpiUnavailableException;
+    method public android.net.IpSecTransform buildTunnelModeTransform(java.net.InetAddress, java.net.InetAddress);
+    method public android.net.IpSecTransform.Builder setAuthentication(int, android.net.IpSecAlgorithm);
+    method public android.net.IpSecTransform.Builder setEncryption(int, android.net.IpSecAlgorithm);
+    method public android.net.IpSecTransform.Builder setIpv4Encapsulation(android.net.IpSecManager.UdpEncapsulationSocket, int);
+    method public android.net.IpSecTransform.Builder setNattKeepalive(int);
+    method public android.net.IpSecTransform.Builder setSpi(int, int);
+    method public android.net.IpSecTransform.Builder setSpi(int, android.net.IpSecManager.SecurityParameterIndex);
+    method public android.net.IpSecTransform.Builder setUnderlyingNetwork(android.net.Network);
+  }
+
   public class LinkAddress implements android.os.Parcelable {
     method public int describeContents();
     method public java.net.InetAddress getAddress();
diff --git a/api/test-current.txt b/api/test-current.txt
index 1979667d8cdd..9620fe2d267f 100644
--- a/api/test-current.txt
+++ b/api/test-current.txt
@@ -8199,6 +8199,7 @@ package android.content {
     field public static final java.lang.String HARDWARE_PROPERTIES_SERVICE = "hardware_properties";
     field public static final java.lang.String INPUT_METHOD_SERVICE = "input_method";
     field public static final java.lang.String INPUT_SERVICE = "input";
+    field public static final java.lang.String IPSEC_SERVICE = "ipsec";
     field public static final java.lang.String JOB_SCHEDULER_SERVICE = "jobscheduler";
     field public static final java.lang.String KEYGUARD_SERVICE = "keyguard";
     field public static final java.lang.String LAUNCHER_APPS_SERVICE = "launcherapps";
@@ -23797,6 +23798,68 @@ package android.net {
     field public static final android.os.Parcelable.Creator<android.net.IpPrefix> CREATOR;
   }
 
+  public final class IpSecAlgorithm implements android.os.Parcelable {
+    ctor public IpSecAlgorithm(java.lang.String, byte[]);
+    ctor public IpSecAlgorithm(java.lang.String, byte[], int);
+    method public int describeContents();
+    method public byte[] getKey();
+    method public java.lang.String getName();
+    method public int getTruncationLengthBits();
+    method public void writeToParcel(android.os.Parcel, int);
+    field public static final java.lang.String ALGO_AUTH_HMAC_MD5 = "hmac(md5)";
+    field public static final java.lang.String ALGO_AUTH_HMAC_SHA1 = "hmac(sha1)";
+    field public static final java.lang.String ALGO_AUTH_HMAC_SHA256 = "hmac(sha256)";
+    field public static final java.lang.String ALGO_AUTH_HMAC_SHA384 = "hmac(sha384)";
+    field public static final java.lang.String ALGO_AUTH_HMAC_SHA512 = "hmac(sha512)";
+    field public static final java.lang.String ALGO_CRYPT_AES_CBC = "cbc(aes)";
+    field public static final android.os.Parcelable.Creator<android.net.IpSecAlgorithm> CREATOR;
+  }
+
+  public final class IpSecManager {
+    method public void applyTransportModeTransform(java.net.Socket, android.net.IpSecTransform) throws java.io.IOException;
+    method public void applyTransportModeTransform(java.net.DatagramSocket, android.net.IpSecTransform) throws java.io.IOException;
+    method public android.net.IpSecManager.UdpEncapsulationSocket openUdpEncapsulationSocket(int) throws java.io.IOException, android.net.IpSecManager.ResourceUnavailableException;
+    method public android.net.IpSecManager.UdpEncapsulationSocket openUdpEncapsulationSocket() throws java.io.IOException, android.net.IpSecManager.ResourceUnavailableException;
+    method public void removeTransportModeTransform(java.net.Socket, android.net.IpSecTransform);
+    method public void removeTransportModeTransform(java.net.DatagramSocket, android.net.IpSecTransform);
+    method public android.net.IpSecManager.SecurityParameterIndex reserveSecurityParameterIndex(java.net.InetAddress, int) throws android.net.IpSecManager.ResourceUnavailableException, android.net.IpSecManager.SpiUnavailableException;
+    field public static final int INVALID_SECURITY_PARAMETER_INDEX = 0; // 0x0
+  }
+
+  public static final class IpSecManager.ResourceUnavailableException extends android.util.AndroidException {
+  }
+
+  public static final class IpSecManager.SecurityParameterIndex implements java.lang.AutoCloseable {
+    method public void close();
+    method public int getSpi();
+  }
+
+  public static final class IpSecManager.SpiUnavailableException extends android.util.AndroidException {
+    method public int getSpi();
+  }
+
+  public static final class IpSecManager.UdpEncapsulationSocket implements java.lang.AutoCloseable {
+    method public void close();
+    method public int getPort();
+    method public java.io.FileDescriptor getSocket();
+  }
+
+  public final class IpSecTransform implements java.lang.AutoCloseable {
+    method public void close();
+    field public static final int DIRECTION_IN = 0; // 0x0
+    field public static final int DIRECTION_OUT = 1; // 0x1
+  }
+
+  public static class IpSecTransform.Builder {
+    ctor public IpSecTransform.Builder(android.content.Context);
+    method public android.net.IpSecTransform buildTransportModeTransform(java.net.InetAddress) throws java.io.IOException, android.net.IpSecManager.ResourceUnavailableException, android.net.IpSecManager.SpiUnavailableException;
+    method public android.net.IpSecTransform.Builder setAuthentication(int, android.net.IpSecAlgorithm);
+    method public android.net.IpSecTransform.Builder setEncryption(int, android.net.IpSecAlgorithm);
+    method public android.net.IpSecTransform.Builder setIpv4Encapsulation(android.net.IpSecManager.UdpEncapsulationSocket, int);
+    method public android.net.IpSecTransform.Builder setSpi(int, int);
+    method public android.net.IpSecTransform.Builder setSpi(int, android.net.IpSecManager.SecurityParameterIndex);
+  }
+
   public class LinkAddress implements android.os.Parcelable {
     method public int describeContents();
     method public java.net.InetAddress getAddress();
diff --git a/core/java/android/content/Context.java b/core/java/android/content/Context.java
index 02b86fe33f3b..46d383597e79 100644
--- a/core/java/android/content/Context.java
+++ b/core/java/android/content/Context.java
@@ -2662,6 +2662,7 @@ public abstract class Context {
             VIBRATOR_SERVICE,
             //@hide: STATUS_BAR_SERVICE,
             CONNECTIVITY_SERVICE,
+            IPSEC_SERVICE,
             //@hide: UPDATE_LOCK_SERVICE,
             //@hide: NETWORKMANAGEMENT_SERVICE,
             NETWORK_STATS_SERVICE,
@@ -2763,6 +2764,9 @@ public abstract class Context {
      *  <dt> {@link #CONNECTIVITY_SERVICE} ("connection")
      *  <dd> A {@link android.net.ConnectivityManager ConnectivityManager} for
      *  handling management of network connections.
+     *  <dt> {@link #IPSEC_SERVICE} ("ipsec")
+     *  <dd> A {@link android.net.IpSecManager IpSecManager} for managing IPSec on
+     *  sockets and networks.
      *  <dt> {@link #WIFI_SERVICE} ("wifi")
      *  <dd> A {@link android.net.wifi.WifiManager WifiManager} for management of Wi-Fi
      *  connectivity.  On releases before NYC, it should only be obtained from an application
@@ -3093,6 +3097,15 @@ public abstract class Context {
     public static final String CONNECTIVITY_SERVICE = "connectivity";
 
     /**
+     * Use with {@link #getSystemService} to retrieve a
+     * {@link android.net.IpSecManager} for encrypting Sockets or Networks with
+     * IPSec.
+     *
+     * @see #getSystemService
+     */
+    public static final String IPSEC_SERVICE = "ipsec";
+
+    /**
      * Use with {@link #getSystemService} to retrieve a {@link
      * android.os.IUpdateLock} for managing runtime sequences that
      * must not be interrupted by headless OTA application or similar.
diff --git a/core/java/android/net/IpSecAlgorithm.java b/core/java/android/net/IpSecAlgorithm.java
new file mode 100644
index 000000000000..da5cb37961ab
--- /dev/null
+++ b/core/java/android/net/IpSecAlgorithm.java
@@ -0,0 +1,181 @@
+/*
+ * Copyright (C) 2017 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;
+
+import android.annotation.StringDef;
+import android.os.Parcel;
+import android.os.Parcelable;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+
+/**
+ * IpSecAlgorithm specifies a single algorithm that can be applied to an IpSec Transform. Refer to
+ * RFC 4301.
+ */
+public final class IpSecAlgorithm implements Parcelable {
+
+    /**
+     * AES-CBC Encryption/Ciphering Algorithm.
+     *
+     * <p>Valid lengths for this key are {128, 192, 256}.
+     */
+    public static final String ALGO_CRYPT_AES_CBC = "cbc(aes)";
+
+    /**
+     * MD5 HMAC Authentication/Integrity Algorithm. This algorithm is not recommended for use in new
+     * applications and is provided for legacy compatibility with 3gpp infrastructure.
+     *
+     * <p>Valid truncation lengths are multiples of 8 bits from 96 to (default) 128.
+     */
+    public static final String ALGO_AUTH_HMAC_MD5 = "hmac(md5)";
+
+    /**
+     * SHA1 HMAC Authentication/Integrity Algorithm. This algorithm is not recommended for use in
+     * new applications and is provided for legacy compatibility with 3gpp infrastructure.
+     *
+     * <p>Valid truncation lengths are multiples of 8 bits from 96 to (default) 160.
+     */
+    public static final String ALGO_AUTH_HMAC_SHA1 = "hmac(sha1)";
+
+    /**
+     * SHA256 HMAC Authentication/Integrity Algorithm.
+     *
+     * <p>Valid truncation lengths are multiples of 8 bits from 96 to (default) 256.
+     */
+    public static final String ALGO_AUTH_HMAC_SHA256 = "hmac(sha256)";
+
+    /**
+     * SHA384 HMAC Authentication/Integrity Algorithm.
+     *
+     * <p>Valid truncation lengths are multiples of 8 bits from 192 to (default) 384.
+     */
+    public static final String ALGO_AUTH_HMAC_SHA384 = "hmac(sha384)";
+    /**
+     * SHA512 HMAC Authentication/Integrity Algorithm
+     *
+     * <p>Valid truncation lengths are multiples of 8 bits from 256 to (default) 512.
+     */
+    public static final String ALGO_AUTH_HMAC_SHA512 = "hmac(sha512)";
+
+    /** @hide */
+    @StringDef({
+        ALGO_CRYPT_AES_CBC,
+        ALGO_AUTH_HMAC_MD5,
+        ALGO_AUTH_HMAC_SHA1,
+        ALGO_AUTH_HMAC_SHA256,
+        ALGO_AUTH_HMAC_SHA512
+    })
+    @Retention(RetentionPolicy.SOURCE)
+    public @interface AlgorithmName {}
+
+    private final String mName;
+    private final byte[] mKey;
+    private final int mTruncLenBits;
+
+    /**
+     * Specify a IpSecAlgorithm of one of the supported types including the truncation length of the
+     * algorithm
+     *
+     * @param algorithm type for IpSec.
+     * @param key non-null Key padded to a multiple of 8 bits.
+     */
+    public IpSecAlgorithm(String algorithm, byte[] key) {
+        this(algorithm, key, key.length * 8);
+    }
+
+    /**
+     * Specify a IpSecAlgorithm of one of the supported types including the truncation length of the
+     * algorithm
+     *
+     * @param algoName precise name of the algorithm to be used.
+     * @param key non-null Key padded to a multiple of 8 bits.
+     * @param truncLenBits the number of bits of output hash to use; only meaningful for
+     *     Authentication.
+     */
+    public IpSecAlgorithm(@AlgorithmName String algoName, byte[] key, int truncLenBits) {
+        if (!isTruncationLengthValid(algoName, truncLenBits)) {
+            throw new IllegalArgumentException("Unknown algorithm or invalid length");
+        }
+        mName = algoName;
+        mKey = key.clone();
+        mTruncLenBits = Math.min(truncLenBits, key.length * 8);
+    }
+
+    /** Retrieve the algorithm name */
+    public String getName() {
+        return mName;
+    }
+
+    /** Retrieve the key for this algorithm */
+    public byte[] getKey() {
+        return mKey.clone();
+    }
+
+    /**
+     * Retrieve the truncation length, in bits, for the key in this algo. By default this will be
+     * the length in bits of the key.
+     */
+    public int getTruncationLengthBits() {
+        return mTruncLenBits;
+    }
+
+    /* Parcelable Implementation */
+    public int describeContents() {
+        return 0;
+    }
+
+    /** Write to parcel */
+    public void writeToParcel(Parcel out, int flags) {
+        out.writeString(mName);
+        out.writeByteArray(mKey);
+        out.writeInt(mTruncLenBits);
+    }
+
+    /** Parcelable Creator */
+    public static final Parcelable.Creator<IpSecAlgorithm> CREATOR =
+            new Parcelable.Creator<IpSecAlgorithm>() {
+                public IpSecAlgorithm createFromParcel(Parcel in) {
+                    return new IpSecAlgorithm(in);
+                }
+
+                public IpSecAlgorithm[] newArray(int size) {
+                    return new IpSecAlgorithm[size];
+                }
+            };
+
+    private IpSecAlgorithm(Parcel in) {
+        mName = in.readString();
+        mKey = in.createByteArray();
+        mTruncLenBits = in.readInt();
+    }
+
+    private static boolean isTruncationLengthValid(String algo, int truncLenBits) {
+        switch (algo) {
+            case ALGO_AUTH_HMAC_MD5:
+                return (truncLenBits >= 96 && truncLenBits <= 128);
+            case ALGO_AUTH_HMAC_SHA1:
+                return (truncLenBits >= 96 && truncLenBits <= 160);
+            case ALGO_AUTH_HMAC_SHA256:
+                return (truncLenBits >= 96 && truncLenBits <= 256);
+            case ALGO_AUTH_HMAC_SHA384:
+                return (truncLenBits >= 192 && truncLenBits <= 384);
+            case ALGO_AUTH_HMAC_SHA512:
+                return (truncLenBits >= 256 && truncLenBits <= 512);
+            default:
+                return false;
+        }
+    }
+};
diff --git a/core/java/android/net/IpSecConfig.aidl b/core/java/android/net/IpSecConfig.aidl
new file mode 100644
index 000000000000..eaefca74d3a0
--- /dev/null
+++ b/core/java/android/net/IpSecConfig.aidl
@@ -0,0 +1,20 @@
+/*
+ * Copyright (C) 2017 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;
+
+/** @hide */
+parcelable IpSecConfig;
diff --git a/core/java/android/net/IpSecConfig.java b/core/java/android/net/IpSecConfig.java
new file mode 100644
index 000000000000..b58bf421a86a
--- /dev/null
+++ b/core/java/android/net/IpSecConfig.java
@@ -0,0 +1,197 @@
+/*
+ * Copyright (C) 2017 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;
+
+import android.os.Parcel;
+import android.os.Parcelable;
+import android.util.Log;
+import java.net.InetAddress;
+import java.net.UnknownHostException;
+
+/** @hide */
+public final class IpSecConfig implements Parcelable {
+    private static final String TAG = IpSecConfig.class.getSimpleName();
+
+    //MODE_TRANSPORT or MODE_TUNNEL
+    int mode;
+
+    // For tunnel mode
+    InetAddress localAddress;
+
+    InetAddress remoteAddress;
+
+    // Limit selection by network interface
+    Network network;
+
+    public static class Flow {
+        // Minimum requirements for identifying a transform
+        // SPI identifying the IPsec flow in packet processing
+        // and a remote IP address
+        int spi;
+
+        // Encryption Algorithm
+        IpSecAlgorithm encryptionAlgo;
+
+        // Authentication Algorithm
+        IpSecAlgorithm authenticationAlgo;
+    }
+
+    Flow[] flow = new Flow[2];
+
+    // For tunnel mode IPv4 UDP Encapsulation
+    // IpSecTransform#ENCAP_ESP_*, such as ENCAP_ESP_OVER_UDP_IKE
+    int encapType;
+    int encapLocalPort;
+    int encapRemotePort;
+
+    // An optional protocol to match with the selector
+    int selectorProto;
+
+    // A bitmask of FEATURE_* indicating which of the fields
+    // of this class are valid.
+    long features;
+
+    // An interval, in seconds between the NattKeepalive packets
+    int nattKeepaliveInterval;
+
+    public InetAddress getLocalIp() {
+        return localAddress;
+    }
+
+    public int getSpi(int direction) {
+        return flow[direction].spi;
+    }
+
+    public InetAddress getRemoteIp() {
+        return remoteAddress;
+    }
+
+    public IpSecAlgorithm getEncryptionAlgo(int direction) {
+        return flow[direction].encryptionAlgo;
+    }
+
+    public IpSecAlgorithm getAuthenticationAlgo(int direction) {
+        return flow[direction].authenticationAlgo;
+    }
+
+    Network getNetwork() {
+        return network;
+    }
+
+    public int getEncapType() {
+        return encapType;
+    }
+
+    public int getEncapLocalPort() {
+        return encapLocalPort;
+    }
+
+    public int getEncapRemotePort() {
+        return encapRemotePort;
+    }
+
+    public int getSelectorProto() {
+        return selectorProto;
+    }
+
+    int getNattKeepaliveInterval() {
+        return nattKeepaliveInterval;
+    }
+
+    public boolean hasProperty(int featureBits) {
+        return (features & featureBits) == featureBits;
+    }
+
+    // Parcelable Methods
+
+    @Override
+    public int describeContents() {
+        return 0;
+    }
+
+    @Override
+    public void writeToParcel(Parcel out, int flags) {
+        out.writeLong(features);
+        // TODO: Use a byte array or other better method for storing IPs that can also include scope
+        out.writeString((localAddress != null) ? localAddress.getHostAddress() : null);
+        // TODO: Use a byte array or other better method for storing IPs that can also include scope
+        out.writeString((remoteAddress != null) ? remoteAddress.getHostAddress() : null);
+        out.writeParcelable(network, flags);
+        out.writeInt(flow[IpSecTransform.DIRECTION_IN].spi);
+        out.writeParcelable(flow[IpSecTransform.DIRECTION_IN].encryptionAlgo, flags);
+        out.writeParcelable(flow[IpSecTransform.DIRECTION_IN].authenticationAlgo, flags);
+        out.writeInt(flow[IpSecTransform.DIRECTION_OUT].spi);
+        out.writeParcelable(flow[IpSecTransform.DIRECTION_OUT].encryptionAlgo, flags);
+        out.writeParcelable(flow[IpSecTransform.DIRECTION_OUT].authenticationAlgo, flags);
+        out.writeInt(encapType);
+        out.writeInt(encapLocalPort);
+        out.writeInt(encapRemotePort);
+        out.writeInt(selectorProto);
+    }
+
+    // Package Private: Used by the IpSecTransform.Builder;
+    // there should be no public constructor for this object
+    IpSecConfig() {
+        flow[IpSecTransform.DIRECTION_IN].spi = 0;
+        flow[IpSecTransform.DIRECTION_OUT].spi = 0;
+        nattKeepaliveInterval = 0; //FIXME constant
+    }
+
+    private static InetAddress readInetAddressFromParcel(Parcel in) {
+        String addrString = in.readString();
+        if (addrString == null) {
+            return null;
+        }
+        try {
+            return InetAddress.getByName(addrString);
+        } catch (UnknownHostException e) {
+            Log.wtf(TAG, "Invalid IpAddress " + addrString);
+            return null;
+        }
+    }
+
+    private IpSecConfig(Parcel in) {
+        features = in.readLong();
+        localAddress = readInetAddressFromParcel(in);
+        remoteAddress = readInetAddressFromParcel(in);
+        network = (Network) in.readParcelable(Network.class.getClassLoader());
+        flow[IpSecTransform.DIRECTION_IN].spi = in.readInt();
+        flow[IpSecTransform.DIRECTION_IN].encryptionAlgo =
+                (IpSecAlgorithm) in.readParcelable(IpSecAlgorithm.class.getClassLoader());
+        flow[IpSecTransform.DIRECTION_IN].authenticationAlgo =
+                (IpSecAlgorithm) in.readParcelable(IpSecAlgorithm.class.getClassLoader());
+        flow[IpSecTransform.DIRECTION_OUT].spi = in.readInt();
+        flow[IpSecTransform.DIRECTION_OUT].encryptionAlgo =
+                (IpSecAlgorithm) in.readParcelable(IpSecAlgorithm.class.getClassLoader());
+        flow[IpSecTransform.DIRECTION_OUT].authenticationAlgo =
+                (IpSecAlgorithm) in.readParcelable(IpSecAlgorithm.class.getClassLoader());
+        encapType = in.readInt();
+        encapLocalPort = in.readInt();
+        encapRemotePort = in.readInt();
+        selectorProto = in.readInt();
+    }
+
+    public static final Parcelable.Creator<IpSecConfig> CREATOR =
+            new Parcelable.Creator<IpSecConfig>() {
+                public IpSecConfig createFromParcel(Parcel in) {
+                    return new IpSecConfig(in);
+                }
+
+                public IpSecConfig[] newArray(int size) {
+                    return new IpSecConfig[size];
+                }
+            };
+}
diff --git a/core/java/android/net/IpSecManager.java b/core/java/android/net/IpSecManager.java
new file mode 100644
index 000000000000..2c544e9b9bfe
--- /dev/null
+++ b/core/java/android/net/IpSecManager.java
@@ -0,0 +1,379 @@
+/*
+ * Copyright (C) 2017 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;
+
+import static com.android.internal.util.Preconditions.checkNotNull;
+
+import android.annotation.SystemApi;
+import android.content.Context;
+import android.os.INetworkManagementService;
+import android.os.ParcelFileDescriptor;
+import android.util.AndroidException;
+import dalvik.system.CloseGuard;
+import java.io.FileDescriptor;
+import java.io.IOException;
+import java.net.DatagramSocket;
+import java.net.InetAddress;
+import java.net.Socket;
+
+/**
+ * This class contains methods for managing IPsec sessions, which will perform kernel-space
+ * encryption and decryption of socket or Network traffic.
+ *
+ * <p>An IpSecManager may be obtained by calling {@link
+ * android.content.Context#getSystemService(String) Context#getSystemService(String)} with {@link
+ * android.content.Context#IPSEC_SERVICE Context#IPSEC_SERVICE}
+ */
+public final class IpSecManager {
+    private static final String TAG = "IpSecManager";
+
+    /**
+     * Indicates that the combination of remote InetAddress and SPI was non-unique for a given
+     * request. If encountered, selection of a new SPI is required before a transform may be
+     * created. Note, this should happen very rarely if the SPI is chosen to be sufficiently random
+     * or reserved using reserveSecurityParameterIndex.
+     */
+    public static final class SpiUnavailableException extends AndroidException {
+        private final int mSpi;
+
+        /**
+         * Construct an exception indicating that a transform with the given SPI is already in use
+         * or otherwise unavailable.
+         *
+         * @param msg Description indicating the colliding SPI
+         * @param spi the SPI that could not be used due to a collision
+         */
+        SpiUnavailableException(String msg, int spi) {
+            super(msg + "(spi: " + spi + ")");
+            mSpi = spi;
+        }
+
+        /** Retrieve the SPI that caused a collision */
+        public int getSpi() {
+            return mSpi;
+        }
+    }
+
+    /**
+     * Indicates that the requested system resource for IPsec, such as a socket or other system
+     * resource is unavailable. If this exception is thrown, try releasing allocated objects of the
+     * type requested.
+     */
+    public static final class ResourceUnavailableException extends AndroidException {
+
+        ResourceUnavailableException(String msg) {
+            super(msg);
+        }
+    }
+
+    private final Context mContext;
+    private final INetworkManagementService mService;
+
+    public static final class SecurityParameterIndex implements AutoCloseable {
+        private final Context mContext;
+        private final InetAddress mDestinationAddress;
+        private final CloseGuard mCloseGuard = CloseGuard.get();
+        private int mSpi;
+
+        /** Return the underlying SPI held by this object */
+        public int getSpi() {
+            return mSpi;
+        }
+
+        private SecurityParameterIndex(Context context, InetAddress destinationAddress, int spi)
+                throws ResourceUnavailableException, SpiUnavailableException {
+            mContext = context;
+            mDestinationAddress = destinationAddress;
+            mSpi = spi;
+            mCloseGuard.open("open");
+        }
+
+        /**
+         * Release an SPI that was previously reserved.
+         *
+         * <p>Release an SPI for use by other users in the system. This will fail if the SPI is
+         * currently in use by an IpSecTransform.
+         *
+         * @param destinationAddress SPIs must be unique for each combination of SPI and destination
+         *     address. Thus, the destinationAddress to which the SPI will communicate must be
+         *     supplied.
+         * @param spi the previously reserved SPI to be freed.
+         */
+        @Override
+        public void close() {
+            mSpi = INVALID_SECURITY_PARAMETER_INDEX; // TODO: Invalid SPI
+            mCloseGuard.close();
+        }
+
+        @Override
+        protected void finalize() {
+            if (mCloseGuard != null) {
+                mCloseGuard.warnIfOpen();
+            }
+
+            close();
+        }
+    }
+
+    /**
+     * The Security Parameter Index, SPI, 0 indicates an unknown or invalid index.
+     *
+     * <p>No IPsec packet may contain an SPI of 0.
+     */
+    public static final int INVALID_SECURITY_PARAMETER_INDEX = 0;
+
+    /**
+     * Reserve an SPI for traffic bound towards the specified destination address.
+     *
+     * <p>If successful, this SPI is guaranteed available until released by a call to {@link
+     * SecurityParameterIndex#close()}.
+     *
+     * @param destinationAddress SPIs must be unique for each combination of SPI and destination
+     *     address.
+     * @param requestedSpi the requested SPI, or '0' to allocate a random SPI.
+     * @return the reserved SecurityParameterIndex
+     * @throws ResourceUnavailableException indicating that too many SPIs are currently allocated
+     *     for this user
+     * @throws SpiUnavailableException indicating that a particular SPI cannot be reserved
+     */
+    public SecurityParameterIndex reserveSecurityParameterIndex(
+            InetAddress destinationAddress, int requestedSpi)
+            throws SpiUnavailableException, ResourceUnavailableException {
+        return new SecurityParameterIndex(mContext, destinationAddress, requestedSpi);
+    }
+
+    /**
+     * Apply an active Transport Mode IPsec Transform to a stream socket to perform IPsec
+     * encapsulation of the traffic flowing between the socket and the remote InetAddress of that
+     * transform. For security reasons, attempts to send traffic to any IP address other than the
+     * address associated with that transform will throw an IOException. In addition, if the
+     * IpSecTransform is later deactivated, the socket will throw an IOException on any calls to
+     * send() or receive() until the transform is removed from the socket by calling {@link
+     * #removeTransportModeTransform(Socket, IpSecTransform)};
+     *
+     * @param socket a stream socket
+     * @param transform an {@link IpSecTransform}, which must be an active Transport Mode transform.
+     */
+    public void applyTransportModeTransform(Socket socket, IpSecTransform transform)
+            throws IOException {
+        applyTransportModeTransform(ParcelFileDescriptor.fromSocket(socket), transform);
+    }
+
+    /**
+     * Apply an active Transport Mode IPsec Transform to a datagram socket to perform IPsec
+     * encapsulation of the traffic flowing between the socket and the remote InetAddress of that
+     * transform. For security reasons, attempts to send traffic to any IP address other than the
+     * address associated with that transform will throw an IOException. In addition, if the
+     * IpSecTransform is later deactivated, the socket will throw an IOException on any calls to
+     * send() or receive() until the transform is removed from the socket by calling {@link
+     * #removeTransportModeTransform(DatagramSocket, IpSecTransform)};
+     *
+     * @param socket a datagram socket
+     * @param transform an {@link IpSecTransform}, which must be an active Transport Mode transform.
+     */
+    public void applyTransportModeTransform(DatagramSocket socket, IpSecTransform transform)
+            throws IOException {
+        applyTransportModeTransform(ParcelFileDescriptor.fromDatagramSocket(socket), transform);
+    }
+
+    /* Call down to activate a transform */
+    private void applyTransportModeTransform(ParcelFileDescriptor pfd, IpSecTransform transform) {}
+
+    /**
+     * Apply an active Tunnel Mode IPsec Transform to a network, which will tunnel all traffic to
+     * and from that network's interface with IPsec (applies an outer IP header and IPsec Header to
+     * all traffic, and expects an additional IP header and IPsec Header on all inbound traffic).
+     * Applications should probably not use this API directly. Instead, they should use {@link
+     * VpnService} to provide VPN capability in a more generic fashion.
+     *
+     * @param net a {@link Network} that will be tunneled via IP Sec.
+     * @param transform an {@link IpSecTransform}, which must be an active Tunnel Mode transform.
+     * @hide
+     */
+    @SystemApi
+    public void applyTunnelModeTransform(Network net, IpSecTransform transform) {}
+
+    /**
+     * Remove a transform from a given stream socket. Once removed, traffic on the socket will not
+     * be encypted. This allows sockets that have been used for IPsec to be reclaimed for
+     * communication in the clear in the event socket reuse is desired. This operation will succeed
+     * regardless of the underlying state of a transform. If a transform is removed, communication
+     * on all sockets to which that transform was applied will fail until this method is called.
+     *
+     * @param socket a socket that previously had a transform applied to it.
+     * @param transform the IPsec Transform that was previously applied to the given socket
+     */
+    public void removeTransportModeTransform(Socket socket, IpSecTransform transform) {
+        removeTransportModeTransform(ParcelFileDescriptor.fromSocket(socket), transform);
+    }
+
+    /**
+     * Remove a transform from a given datagram socket. Once removed, traffic on the socket will not
+     * be encypted. This allows sockets that have been used for IPsec to be reclaimed for
+     * communication in the clear in the event socket reuse is desired. This operation will succeed
+     * regardless of the underlying state of a transform. If a transform is removed, communication
+     * on all sockets to which that transform was applied will fail until this method is called.
+     *
+     * @param socket a socket that previously had a transform applied to it.
+     * @param transform the IPsec Transform that was previously applied to the given socket
+     */
+    public void removeTransportModeTransform(DatagramSocket socket, IpSecTransform transform) {
+        removeTransportModeTransform(ParcelFileDescriptor.fromDatagramSocket(socket), transform);
+    }
+
+    /* Call down to activate a transform */
+    private void removeTransportModeTransform(ParcelFileDescriptor pfd, IpSecTransform transform) {}
+
+    /**
+     * Remove a Tunnel Mode IPsec Transform from a {@link Network}. This must be used as part of
+     * cleanup if a tunneled Network experiences a change in default route. The Network will drop
+     * all traffic that cannot be routed to the Tunnel's outbound interface. If that interface is
+     * lost, all traffic will drop.
+     *
+     * @param net a network that currently has transform applied to it.
+     * @param transform a Tunnel Mode IPsec Transform that has been previously applied to the given
+     *     network
+     * @hide
+     */
+    @SystemApi
+    public void removeTunnelModeTransform(Network net, IpSecTransform transform) {}
+
+    /**
+     * Class providing access to a system-provided UDP Encapsulation Socket, which may be used for
+     * IKE signalling as well as for inbound and outbound UDP encapsulated IPsec traffic.
+     *
+     * <p>The socket provided by this class cannot be re-bound or closed via the inner
+     * FileDescriptor. Instead, disposing of this socket requires a call to close().
+     */
+    public static final class UdpEncapsulationSocket implements AutoCloseable {
+        private final FileDescriptor mFd;
+        private final Context mContext;
+        private final CloseGuard mCloseGuard = CloseGuard.get();
+
+        private UdpEncapsulationSocket(Context context, int port)
+                throws ResourceUnavailableException {
+            mContext = context;
+            mCloseGuard.open("constructor");
+            // TODO: go down to the kernel and get a socket on the specified
+            mFd = new FileDescriptor();
+        }
+
+        private UdpEncapsulationSocket(Context context) throws ResourceUnavailableException {
+            mContext = context;
+            mCloseGuard.open("constructor");
+            // TODO: go get a random socket on a random port
+            mFd = new FileDescriptor();
+        }
+
+        /** Access the inner UDP Encapsulation Socket */
+        public FileDescriptor getSocket() {
+            return mFd;
+        }
+
+        /** Retrieve the port number of the inner encapsulation socket */
+        public int getPort() {
+            return 0; // TODO get the port number from the Socket;
+        }
+
+        @Override
+        /**
+         * Release the resources that have been reserved for this Socket.
+         *
+         * <p>This method closes the underlying socket, reducing a user's allocated sockets in the
+         * system. This must be done as part of cleanup following use of a socket. Failure to do so
+         * will cause the socket to count against a total allocation limit for IpSec and eventually
+         * fail due to resource limits.
+         *
+         * @param fd a file descriptor previously returned as a UDP Encapsulation socket.
+         */
+        public void close() {
+            // TODO: Go close the socket
+            mCloseGuard.close();
+        }
+
+        @Override
+        protected void finalize() throws Throwable {
+            if (mCloseGuard != null) {
+                mCloseGuard.warnIfOpen();
+            }
+
+            close();
+        }
+    };
+
+    /**
+     * Open a socket that is bound to a free UDP port on the system.
+     *
+     * <p>By binding in this manner and holding the FileDescriptor, the socket cannot be un-bound by
+     * the caller. This provides safe access to a socket on a port that can later be used as a UDP
+     * Encapsulation port.
+     *
+     * <p>This socket reservation works in conjunction with IpSecTransforms, which may re-use the
+     * socket port. Explicitly opening this port is only necessary if communication is desired on
+     * that port.
+     *
+     * @param port a local UDP port to be reserved for UDP Encapsulation. is provided, then this
+     *     method will bind to the specified port or fail. To retrieve the port number, call {@link
+     *     android.system.Os#getsockname(FileDescriptor)}.
+     * @return a {@link UdpEncapsulationSocket} that is bound to the requested port for the lifetime
+     *     of the object.
+     */
+    // Returning a socket in this fashion that has been created and bound by the system
+    // is the only safe way to ensure that a socket is both accessible to the user and
+    // safely usable for Encapsulation without allowing a user to possibly unbind from/close
+    // the port, which could potentially impact the traffic of the next user who binds to that
+    // socket.
+    public UdpEncapsulationSocket openUdpEncapsulationSocket(int port)
+            throws IOException, ResourceUnavailableException {
+        // Temporary code
+        return new UdpEncapsulationSocket(mContext, port);
+    }
+
+    /**
+     * Open a socket that is bound to a port selected by the system.
+     *
+     * <p>By binding in this manner and holding the FileDescriptor, the socket cannot be un-bound by
+     * the caller. This provides safe access to a socket on a port that can later be used as a UDP
+     * Encapsulation port.
+     *
+     * <p>This socket reservation works in conjunction with IpSecTransforms, which may re-use the
+     * socket port. Explicitly opening this port is only necessary if communication is desired on
+     * that port.
+     *
+     * @return a {@link UdpEncapsulationSocket} that is bound to an arbitrarily selected port
+     */
+    // Returning a socket in this fashion that has been created and bound by the system
+    // is the only safe way to ensure that a socket is both accessible to the user and
+    // safely usable for Encapsulation without allowing a user to possibly unbind from/close
+    // the port, which could potentially impact the traffic of the next user who binds to that
+    // socket.
+    public UdpEncapsulationSocket openUdpEncapsulationSocket()
+            throws IOException, ResourceUnavailableException {
+        // Temporary code
+        return new UdpEncapsulationSocket(mContext);
+    }
+
+    /**
+     * Retrieve an instance of an IpSecManager within you application context
+     *
+     * @param context the application context for this manager
+     * @hide
+     */
+    public IpSecManager(Context context, INetworkManagementService service) {
+        mContext = checkNotNull(context, "missing context");
+        mService = checkNotNull(service, "missing service");
+    }
+}
diff --git a/core/java/android/net/IpSecTransform.java b/core/java/android/net/IpSecTransform.java
new file mode 100644
index 000000000000..d6dd28bec390
--- /dev/null
+++ b/core/java/android/net/IpSecTransform.java
@@ -0,0 +1,471 @@
+/*
+ * Copyright (C) 2017 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;
+
+import android.annotation.IntDef;
+import android.annotation.SystemApi;
+import android.content.Context;
+import android.system.ErrnoException;
+import android.util.Log;
+import dalvik.system.CloseGuard;
+import java.io.IOException;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.net.InetAddress;
+
+/**
+ * This class represents an IpSecTransform, which encapsulates both properties and state of IPsec.
+ *
+ * <p>IpSecTransforms must be built from an IpSecTransform.Builder, and they must persist throughout
+ * the lifetime of the underlying transform. If a transform object leaves scope, the underlying
+ * transform may be disabled automatically, with likely undesirable results.
+ *
+ * <p>An IpSecTransform may either represent a tunnel mode transform that operates on a wide array
+ * of traffic or may represent a transport mode transform operating on a Socket or Sockets.
+ */
+public final class IpSecTransform implements AutoCloseable {
+    private static final String TAG = "IpSecTransform";
+
+    /**
+     * For direction-specific attributes of an IpSecTransform, indicates that an attribute applies
+     * to traffic towards the host.
+     */
+    public static final int DIRECTION_IN = 0;
+
+    /**
+     * For direction-specific attributes of an IpSecTransform, indicates that an attribute applies
+     * to traffic from the host.
+     */
+    public static final int DIRECTION_OUT = 1;
+
+    /** @hide */
+    @IntDef(value = {DIRECTION_IN, DIRECTION_OUT})
+    @Retention(RetentionPolicy.SOURCE)
+    public @interface TransformDirection {}
+
+    /** @hide */
+    private static final int MODE_TUNNEL = 0;
+
+    /** @hide */
+    private static final int MODE_TRANSPORT = 1;
+
+    /** @hide */
+    public static final int ENCAP_NONE = 0;
+
+    /**
+     * IpSec traffic will be encapsulated within UDP as per <a
+     * href="https://tools.ietf.org/html/rfc3948">RFC3498</a>.
+     *
+     * @hide
+     */
+    public static final int ENCAP_ESPINUDP = 1;
+
+    /**
+     * IpSec traffic will be encapsulated within a UDP header with an additional 8-byte header pad
+     * (of '0'-value bytes) that prevents traffic from being interpreted as IKE or as ESP over UDP.
+     *
+     * @hide
+     */
+    public static final int ENCAP_ESPINUDP_NONIKE = 2;
+
+    /** @hide */
+    @IntDef(value = {ENCAP_NONE, ENCAP_ESPINUDP, ENCAP_ESPINUDP_NONIKE})
+    @Retention(RetentionPolicy.SOURCE)
+    public @interface EncapType {}
+
+    /**
+     * Sentinel for an invalid transform (means that this transform is inactive).
+     *
+     * @hide
+     */
+    public static final int INVALID_TRANSFORM_ID = -1;
+
+    private IpSecTransform(Context context, IpSecConfig config) {
+        mContext = context;
+        mConfig = config;
+        mTransformId = INVALID_TRANSFORM_ID;
+    }
+
+    private IpSecTransform activate()
+            throws IOException, IpSecManager.ResourceUnavailableException,
+                    IpSecManager.SpiUnavailableException {
+        int transformId;
+        synchronized (this) {
+            //try {
+            transformId = INVALID_TRANSFORM_ID;
+            //} catch (RemoteException e) {
+            //    throw e.rethrowFromSystemServer();
+            //}
+
+            if (transformId < 0) {
+                throw new ErrnoException("addTransform", -transformId).rethrowAsIOException();
+            }
+
+            startKeepalive(mContext); // Will silently fail if not required
+            mTransformId = transformId;
+            Log.d(TAG, "Added Transform with Id " + transformId);
+        }
+        mCloseGuard.open("build");
+
+        return this;
+    }
+
+    /**
+     * Deactivate an IpSecTransform and free all resources for that transform that are managed by
+     * the system for this Transform.
+     *
+     * <p>Deactivating a transform while it is still applied to any Socket will result in sockets
+     * refusing to send or receive data. This method will silently succeed if the specified
+     * transform has already been removed; thus, it is always safe to attempt cleanup when a
+     * transform is no longer needed.
+     */
+    public void close() {
+        Log.d(TAG, "Removing Transform with Id " + mTransformId);
+
+        // Always safe to attempt cleanup
+        if (mTransformId == INVALID_TRANSFORM_ID) {
+            return;
+        }
+        //try {
+        stopKeepalive();
+        //} catch (RemoteException e) {
+        //    transform.setTransformId(transformId);
+        //    throw e.rethrowFromSystemServer();
+        //} finally {
+        mTransformId = INVALID_TRANSFORM_ID;
+        //}
+        mCloseGuard.close();
+    }
+
+    @Override
+    protected void finalize() throws Throwable {
+        if (mCloseGuard != null) {
+            mCloseGuard.warnIfOpen();
+        }
+        close();
+    }
+
+    /* Package */
+    IpSecConfig getConfig() {
+        return mConfig;
+    }
+
+    private final IpSecConfig mConfig;
+    private int mTransformId;
+    private final Context mContext;
+    private final CloseGuard mCloseGuard = CloseGuard.get();
+    private ConnectivityManager.PacketKeepalive mKeepalive;
+    private int mKeepaliveStatus = ConnectivityManager.PacketKeepalive.NO_KEEPALIVE;
+    private Object mKeepaliveSyncLock = new Object();
+    private ConnectivityManager.PacketKeepaliveCallback mKeepaliveCallback =
+            new ConnectivityManager.PacketKeepaliveCallback() {
+
+                @Override
+                public void onStarted() {
+                    synchronized (mKeepaliveSyncLock) {
+                        mKeepaliveStatus = ConnectivityManager.PacketKeepalive.SUCCESS;
+                        mKeepaliveSyncLock.notifyAll();
+                    }
+                }
+
+                @Override
+                public void onStopped() {
+                    synchronized (mKeepaliveSyncLock) {
+                        mKeepaliveStatus = ConnectivityManager.PacketKeepalive.NO_KEEPALIVE;
+                        mKeepaliveSyncLock.notifyAll();
+                    }
+                }
+
+                @Override
+                public void onError(int error) {
+                    synchronized (mKeepaliveSyncLock) {
+                        mKeepaliveStatus = error;
+                        mKeepaliveSyncLock.notifyAll();
+                    }
+                }
+            };
+
+    /* Package */
+    void startKeepalive(Context c) {
+        if (mConfig.getNattKeepaliveInterval() == 0) {
+            return;
+        }
+
+        ConnectivityManager cm =
+                (ConnectivityManager) c.getSystemService(Context.CONNECTIVITY_SERVICE);
+
+        if (mKeepalive != null) {
+            Log.e(TAG, "Keepalive already started for this IpSecTransform.");
+            return;
+        }
+
+        synchronized (mKeepaliveSyncLock) {
+            mKeepalive =
+                    cm.startNattKeepalive(
+                            mConfig.getNetwork(),
+                            mConfig.getNattKeepaliveInterval(),
+                            mKeepaliveCallback,
+                            mConfig.getLocalIp(),
+                            mConfig.getEncapLocalPort(),
+                            mConfig.getRemoteIp());
+            try {
+                mKeepaliveSyncLock.wait(2000);
+            } catch (InterruptedException e) {
+            }
+        }
+        if (mKeepaliveStatus != ConnectivityManager.PacketKeepalive.SUCCESS) {
+            throw new UnsupportedOperationException("Packet Keepalive cannot be started");
+        }
+    }
+
+    /* Package */
+    void stopKeepalive() {
+        if (mKeepalive == null) {
+            return;
+        }
+        mKeepalive.stop();
+        synchronized (mKeepaliveSyncLock) {
+            if (mKeepaliveStatus == ConnectivityManager.PacketKeepalive.SUCCESS) {
+                try {
+                    mKeepaliveSyncLock.wait(2000);
+                } catch (InterruptedException e) {
+                }
+            }
+        }
+    }
+
+    /* Package */
+    void setTransformId(int transformId) {
+        mTransformId = transformId;
+    }
+
+    /* Package */
+    int getTransformId() {
+        return mTransformId;
+    }
+
+    /**
+     * Builder object to facilitate the creation of IpSecTransform objects.
+     *
+     * <p>Apply additional properties to the transform and then call a build() method to return an
+     * IpSecTransform object.
+     *
+     * @see Builder#buildTransportModeTransform(InetAddress)
+     */
+    public static class Builder {
+        private Context mContext;
+        private IpSecConfig mConfig;
+
+        /**
+         * Add an encryption algorithm to the transform for the given direction.
+         *
+         * <p>If encryption is set for a given direction without also providing an SPI for that
+         * direction, creation of an IpSecTransform will fail upon calling a build() method.
+         *
+         * @param direction either {@link #DIRECTION_IN or #DIRECTION_OUT}
+         * @param algo {@link IpSecAlgorithm} specifying the encryption to be applied.
+         */
+        public IpSecTransform.Builder setEncryption(
+                @TransformDirection int direction, IpSecAlgorithm algo) {
+            mConfig.flow[direction].encryptionAlgo = algo;
+            return this;
+        }
+
+        /**
+         * Add an authentication/integrity algorithm to the transform.
+         *
+         * <p>If authentication is set for a given direction without also providing an SPI for that
+         * direction, creation of an IpSecTransform will fail upon calling a build() method.
+         *
+         * @param direction either {@link #DIRECTION_IN or #DIRECTION_OUT}
+         * @param algo {@link IpSecAlgorithm} specifying the authentication to be applied.
+         */
+        public IpSecTransform.Builder setAuthentication(
+                @TransformDirection int direction, IpSecAlgorithm algo) {
+            mConfig.flow[direction].authenticationAlgo = algo;
+            return this;
+        }
+
+        /**
+         * Set the SPI, which uniquely identifies a particular IPsec session from others. Because
+         * IPsec operates at the IP layer, this 32-bit identifier uniquely identifies packets to a
+         * given destination address.
+         *
+         * <p>Care should be chosen when selecting an SPI to ensure that is is as unique as
+         * possible. Random number generation is a reasonable approach to selecting an SPI. For
+         * outbound SPIs, they must be reserved by calling {@link
+         * IpSecManager#reserveSecurityParameterIndex(InetAddress, int)}. Otherwise, Transforms will
+         * fail to build.
+         *
+         * <p>Unless an SPI is set for a given direction, traffic in that direction will be
+         * sent/received without any IPsec applied.
+         *
+         * @param direction either {@link #DIRECTION_IN or #DIRECTION_OUT}
+         * @param spi a unique 32-bit integer to identify transformed traffic
+         */
+        public IpSecTransform.Builder setSpi(@TransformDirection int direction, int spi) {
+            mConfig.flow[direction].spi = spi;
+            return this;
+        }
+
+        /**
+         * Set the SPI, which uniquely identifies a particular IPsec session from others. Because
+         * IPsec operates at the IP layer, this 32-bit identifier uniquely identifies packets to a
+         * given destination address.
+         *
+         * <p>Care should be chosen when selecting an SPI to ensure that is is as unique as
+         * possible. Random number generation is a reasonable approach to selecting an SPI. For
+         * outbound SPIs, they must be reserved by calling {@link
+         * IpSecManager#reserveSecurityParameterIndex(InetAddress, int)}. Otherwise, Transforms will
+         * fail to activate.
+         *
+         * <p>Unless an SPI is set for a given direction, traffic in that direction will be
+         * sent/received without any IPsec applied.
+         *
+         * @param direction either {@link #DIRECTION_IN or #DIRECTION_OUT}
+         * @param spi a unique {@link IpSecManager.SecurityParameterIndex} to identify transformed
+         *     traffic
+         */
+        public IpSecTransform.Builder setSpi(
+                @TransformDirection int direction, IpSecManager.SecurityParameterIndex spi) {
+            mConfig.flow[direction].spi = spi.getSpi();
+            return this;
+        }
+
+        /**
+         * Specify the network on which this transform will emit its traffic; (otherwise it will
+         * emit on the default network).
+         *
+         * <p>Restricts the transformed traffic to a particular {@link Network}. This is required in
+         * tunnel mode.
+         *
+         * @hide
+         */
+        @SystemApi
+        public IpSecTransform.Builder setUnderlyingNetwork(Network net) {
+            mConfig.network = net;
+            return this;
+        }
+
+        /**
+         * Add UDP encapsulation to an IPv4 transform
+         *
+         * <p>This option allows IPsec traffic to pass through NAT. Refer to RFC 3947 and 3948 for
+         * details on how UDP should be applied to IPsec.
+         *
+         * @param localSocket a {@link IpSecManager.UdpEncapsulationSocket} for sending and
+         *     receiving encapsulating traffic.
+         * @param remotePort the UDP port number of the remote that will send and receive
+         *     encapsulated traffic. In the case of IKE, this is likely port 4500.
+         */
+        public IpSecTransform.Builder setIpv4Encapsulation(
+                IpSecManager.UdpEncapsulationSocket localSocket, int remotePort) {
+            // TODO: check encap type is valid.
+            mConfig.encapType = ENCAP_ESPINUDP;
+            mConfig.encapLocalPort = localSocket.getPort(); // TODO: plug in the encap socket
+            mConfig.encapRemotePort = remotePort;
+            return this;
+        }
+
+        // TODO: Decrease the minimum keepalive to maybe 10?
+        // TODO: Probably a better exception to throw for NATTKeepalive failure
+        // TODO: Specify the needed NATT keepalive permission.
+        /**
+         * Send a NATT Keepalive packet with a given maximum interval. This will create an offloaded
+         * request to do power-efficient NATT Keepalive. If NATT keepalive is requested but cannot
+         * be activated, then the transform will fail to activate and throw an IOException.
+         *
+         * @param intervalSeconds the maximum number of seconds between keepalive packets, no less
+         *     than 20s and no more than 3600s.
+         * @hide
+         */
+        @SystemApi
+        public IpSecTransform.Builder setNattKeepalive(int intervalSeconds) {
+            mConfig.nattKeepaliveInterval = intervalSeconds;
+            return this;
+        }
+
+        /**
+         * Build and return an active {@link IpSecTransform} object as a Transport Mode Transform.
+         * Some parameters have interdependencies that are checked at build time. If a well-formed
+         * transform cannot be created from the supplied parameters, this method will throw an
+         * Exception.
+         *
+         * <p>Upon a successful return from this call, the provided IpSecTransform will be active
+         * and may be applied to sockets. If too many IpSecTransform objects are active for a given
+         * user this operation will fail and throw ResourceUnavailableException. To avoid these
+         * exceptions, unused Transform objects must be cleaned up by calling {@link
+         * IpSecTransform#close()} when they are no longer needed.
+         *
+         * @param remoteAddress the {@link InetAddress} that, when matched on traffic to/from this
+         *     socket will cause the transform to be applied.
+         *     <p>Note that an active transform will not impact any network traffic until it has
+         *     been applied to one or more Sockets. Calling this method is a necessary precondition
+         *     for applying it to a socket, but is not sufficient to actually apply IPsec.
+         * @throws IllegalArgumentException indicating that a particular combination of transform
+         *     properties is invalid.
+         * @throws IpSecManager.ResourceUnavailableException in the event that no more Transforms
+         *     may be allocated
+         * @throws SpiUnavailableException if the SPI collides with an existing transform
+         *     (unlikely).
+         * @throws ResourceUnavailableException if the current user currently has exceeded the
+         *     number of allowed active transforms.
+         */
+        public IpSecTransform buildTransportModeTransform(InetAddress remoteAddress)
+                throws IpSecManager.ResourceUnavailableException,
+                        IpSecManager.SpiUnavailableException, IOException {
+            //FIXME: argument validation here
+            //throw new IllegalArgumentException("Natt Keepalive requires UDP Encapsulation");
+            mConfig.mode = MODE_TRANSPORT;
+            mConfig.remoteAddress = remoteAddress;
+            return new IpSecTransform(mContext, mConfig).activate();
+        }
+
+        /**
+         * Build and return an {@link IpSecTransform} object as a Tunnel Mode Transform. Some
+         * parameters have interdependencies that are checked at build time.
+         *
+         * @param localAddress the {@link InetAddress} that provides the local endpoint for this
+         *     IPsec tunnel. This is almost certainly an address belonging to the {@link Network}
+         *     that will originate the traffic, which is set as the {@link #setUnderlyingNetwork}.
+         * @param remoteAddress the {@link InetAddress} representing the remote endpoint of this
+         *     IPsec tunnel.
+         * @throws IllegalArgumentException indicating that a particular combination of transform
+         *     properties is invalid.
+         * @hide
+         */
+        @SystemApi
+        public IpSecTransform buildTunnelModeTransform(
+                InetAddress localAddress, InetAddress remoteAddress) {
+            //FIXME: argument validation here
+            //throw new IllegalArgumentException("Natt Keepalive requires UDP Encapsulation");
+            mConfig.localAddress = localAddress;
+            mConfig.remoteAddress = remoteAddress;
+            mConfig.mode = MODE_TUNNEL;
+            return new IpSecTransform(mContext, mConfig);
+        }
+
+        /**
+         * Create a new IpSecTransform.Builder to construct an IpSecTransform
+         *
+         * @param context current Context
+         */
+        public Builder(Context context) {
+            mContext = context;
+            mConfig = new IpSecConfig();
+        }
+    }
+}