diff --git a/service-t/Sources.bp b/service-t/Sources.bp
index 6a64910..7b88176 100644
--- a/service-t/Sources.bp
+++ b/service-t/Sources.bp
@@ -48,16 +48,28 @@
     ],
 }
 
+// IpSec related libraries.
+
+filegroup {
+    name: "services.connectivity-ipsec-sources",
+    srcs: [
+        "src/com/android/server/IpSecService.java",
+    ],
+    path: "src",
+    visibility: [
+        "//visibility:private",
+    ],
+}
+
 // Connectivity-T common libraries.
 
 filegroup {
     name: "services.connectivity-tiramisu-sources",
     srcs: [
+        ":services.connectivity-ipsec-sources",
         ":services.connectivity-netstats-sources",
         ":services.connectivity-nsd-sources",
     ],
     path: "src",
-    visibility: [
-        "//frameworks/base/services/core",
-    ],
-}
\ No newline at end of file
+    visibility: ["//frameworks/base/services/core"],
+}
diff --git a/service-t/src/com/android/server/IpSecService.java b/service-t/src/com/android/server/IpSecService.java
new file mode 100644
index 0000000..aeb8143
--- /dev/null
+++ b/service-t/src/com/android/server/IpSecService.java
@@ -0,0 +1,1917 @@
+/*
+ * 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 com.android.server;
+
+import static android.Manifest.permission.DUMP;
+import static android.net.IpSecManager.INVALID_RESOURCE_ID;
+import static android.system.OsConstants.AF_INET;
+import static android.system.OsConstants.AF_INET6;
+import static android.system.OsConstants.AF_UNSPEC;
+import static android.system.OsConstants.EINVAL;
+import static android.system.OsConstants.IPPROTO_UDP;
+import static android.system.OsConstants.SOCK_DGRAM;
+
+import android.annotation.NonNull;
+import android.app.AppOpsManager;
+import android.content.Context;
+import android.content.pm.PackageManager;
+import android.net.ConnectivityManager;
+import android.net.IIpSecService;
+import android.net.INetd;
+import android.net.InetAddresses;
+import android.net.IpSecAlgorithm;
+import android.net.IpSecConfig;
+import android.net.IpSecManager;
+import android.net.IpSecSpiResponse;
+import android.net.IpSecTransform;
+import android.net.IpSecTransformResponse;
+import android.net.IpSecTunnelInterfaceResponse;
+import android.net.IpSecUdpEncapResponse;
+import android.net.LinkAddress;
+import android.net.LinkProperties;
+import android.net.Network;
+import android.net.TrafficStats;
+import android.net.util.NetdService;
+import android.os.Binder;
+import android.os.IBinder;
+import android.os.ParcelFileDescriptor;
+import android.os.Process;
+import android.os.RemoteException;
+import android.os.ServiceSpecificException;
+import android.system.ErrnoException;
+import android.system.Os;
+import android.system.OsConstants;
+import android.text.TextUtils;
+import android.util.Log;
+import android.util.Range;
+import android.util.SparseArray;
+import android.util.SparseBooleanArray;
+
+import com.android.internal.annotations.GuardedBy;
+import com.android.internal.annotations.VisibleForTesting;
+import com.android.internal.util.Preconditions;
+import com.android.net.module.util.BinderUtils;
+import com.android.net.module.util.NetdUtils;
+import com.android.net.module.util.PermissionUtils;
+
+import libcore.io.IoUtils;
+
+import java.io.FileDescriptor;
+import java.io.IOException;
+import java.io.PrintWriter;
+import java.net.Inet4Address;
+import java.net.Inet6Address;
+import java.net.InetAddress;
+import java.net.InetSocketAddress;
+import java.net.UnknownHostException;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Objects;
+
+/**
+ * A service to manage multiple clients that want to access the IpSec API. The service is
+ * responsible for maintaining a list of clients and managing the resources (and related quotas)
+ * that each of them own.
+ *
+ * <p>Synchronization in IpSecService is done on all entrypoints due to potential race conditions at
+ * the kernel/xfrm level. Further, this allows the simplifying assumption to be made that only one
+ * thread is ever running at a time.
+ *
+ * @hide
+ */
+public class IpSecService extends IIpSecService.Stub {
+    private static final String TAG = "IpSecService";
+    private static final boolean DBG = Log.isLoggable(TAG, Log.DEBUG);
+
+    private static final String NETD_SERVICE_NAME = "netd";
+    private static final int[] ADDRESS_FAMILIES =
+            new int[] {OsConstants.AF_INET, OsConstants.AF_INET6};
+
+    private static final int NETD_FETCH_TIMEOUT_MS = 5000; // ms
+    private static final InetAddress INADDR_ANY;
+
+    @VisibleForTesting static final int MAX_PORT_BIND_ATTEMPTS = 10;
+
+    static {
+        try {
+            INADDR_ANY = InetAddress.getByAddress(new byte[] {0, 0, 0, 0});
+        } catch (UnknownHostException e) {
+            throw new RuntimeException(e);
+        }
+    }
+
+    static final int FREE_PORT_MIN = 1024; // ports 1-1023 are reserved
+    static final int PORT_MAX = 0xFFFF; // ports are an unsigned 16-bit integer
+
+    /* Binder context for this service */
+    private final Context mContext;
+
+    /**
+     * The next non-repeating global ID for tracking resources between users, this service, and
+     * kernel data structures. Accessing this variable is not thread safe, so it is only read or
+     * modified within blocks synchronized on IpSecService.this. We want to avoid -1
+     * (INVALID_RESOURCE_ID) and 0 (we probably forgot to initialize it).
+     */
+    @GuardedBy("IpSecService.this")
+    private int mNextResourceId = 1;
+
+    interface IpSecServiceConfiguration {
+        INetd getNetdInstance() throws RemoteException;
+
+        static IpSecServiceConfiguration GETSRVINSTANCE =
+                new IpSecServiceConfiguration() {
+                    @Override
+                    public INetd getNetdInstance() throws RemoteException {
+                        final INetd netd = NetdService.getInstance();
+                        if (netd == null) {
+                            throw new RemoteException("Failed to Get Netd Instance");
+                        }
+                        return netd;
+                    }
+                };
+    }
+
+    private final IpSecServiceConfiguration mSrvConfig;
+    final UidFdTagger mUidFdTagger;
+
+    /**
+     * Interface for user-reference and kernel-resource cleanup.
+     *
+     * <p>This interface must be implemented for a resource to be reference counted.
+     */
+    @VisibleForTesting
+    public interface IResource {
+        /**
+         * Invalidates a IResource object, ensuring it is invalid for the purposes of allocating new
+         * objects dependent on it.
+         *
+         * <p>Implementations of this method are expected to remove references to the IResource
+         * object from the IpSecService's tracking arrays. The removal from the arrays ensures that
+         * the resource is considered invalid for user access or allocation or use in other
+         * resources.
+         *
+         * <p>References to the IResource object may be held by other RefcountedResource objects,
+         * and as such, the underlying resources and quota may not be cleaned up.
+         */
+        void invalidate() throws RemoteException;
+
+        /**
+         * Releases underlying resources and related quotas.
+         *
+         * <p>Implementations of this method are expected to remove all system resources that are
+         * tracked by the IResource object. Due to other RefcountedResource objects potentially
+         * having references to the IResource object, freeUnderlyingResources may not always be
+         * called from releaseIfUnreferencedRecursively().
+         */
+        void freeUnderlyingResources() throws RemoteException;
+    }
+
+    /**
+     * RefcountedResource manages references and dependencies in an exclusively acyclic graph.
+     *
+     * <p>RefcountedResource implements both explicit and implicit resource management. Creating a
+     * RefcountedResource object creates an explicit reference that must be freed by calling
+     * userRelease(). Additionally, adding this object as a child of another RefcountedResource
+     * object will add an implicit reference.
+     *
+     * <p>Resources are cleaned up when all references, both implicit and explicit, are released
+     * (ie, when userRelease() is called and when all parents have called releaseReference() on this
+     * object.)
+     */
+    @VisibleForTesting
+    public class RefcountedResource<T extends IResource> implements IBinder.DeathRecipient {
+        private final T mResource;
+        private final List<RefcountedResource> mChildren;
+        int mRefCount = 1; // starts at 1 for user's reference.
+        IBinder mBinder;
+
+        RefcountedResource(T resource, IBinder binder, RefcountedResource... children) {
+            synchronized (IpSecService.this) {
+                this.mResource = resource;
+                this.mChildren = new ArrayList<>(children.length);
+                this.mBinder = binder;
+
+                for (RefcountedResource child : children) {
+                    mChildren.add(child);
+                    child.mRefCount++;
+                }
+
+                try {
+                    mBinder.linkToDeath(this, 0);
+                } catch (RemoteException e) {
+                    binderDied();
+                    e.rethrowFromSystemServer();
+                }
+            }
+        }
+
+        /**
+         * If the Binder object dies, this function is called to free the system resources that are
+         * being tracked by this record and to subsequently release this record for garbage
+         * collection
+         */
+        @Override
+        public void binderDied() {
+            synchronized (IpSecService.this) {
+                try {
+                    userRelease();
+                } catch (Exception e) {
+                    Log.e(TAG, "Failed to release resource: " + e);
+                }
+            }
+        }
+
+        public T getResource() {
+            return mResource;
+        }
+
+        /**
+         * Unlinks from binder and performs IpSecService resource cleanup (removes from resource
+         * arrays)
+         *
+         * <p>If this method has been previously called, the RefcountedResource's binder field will
+         * be null, and the method will return without performing the cleanup a second time.
+         *
+         * <p>Note that calling this function does not imply that kernel resources will be freed at
+         * this time, or that the related quota will be returned. Such actions will only be
+         * performed upon the reference count reaching zero.
+         */
+        @GuardedBy("IpSecService.this")
+        public void userRelease() throws RemoteException {
+            // Prevent users from putting reference counts into a bad state by calling
+            // userRelease() multiple times.
+            if (mBinder == null) {
+                return;
+            }
+
+            mBinder.unlinkToDeath(this, 0);
+            mBinder = null;
+
+            mResource.invalidate();
+
+            releaseReference();
+        }
+
+        /**
+         * Removes a reference to this resource. If the resultant reference count is zero, the
+         * underlying resources are freed, and references to all child resources are also dropped
+         * recursively (resulting in them freeing their resources and children, etcetera)
+         *
+         * <p>This method also sets the reference count to an invalid value (-1) to signify that it
+         * has been fully released. Any subsequent calls to this method will result in an
+         * IllegalStateException being thrown due to resource already having been previously
+         * released
+         */
+        @VisibleForTesting
+        @GuardedBy("IpSecService.this")
+        public void releaseReference() throws RemoteException {
+            mRefCount--;
+
+            if (mRefCount > 0) {
+                return;
+            } else if (mRefCount < 0) {
+                throw new IllegalStateException(
+                        "Invalid operation - resource has already been released.");
+            }
+
+            // Cleanup own resources
+            mResource.freeUnderlyingResources();
+
+            // Cleanup child resources as needed
+            for (RefcountedResource<? extends IResource> child : mChildren) {
+                child.releaseReference();
+            }
+
+            // Enforce that resource cleanup can only be called once
+            // By decrementing the refcount (from 0 to -1), the next call will throw an
+            // IllegalStateException - it has already been released fully.
+            mRefCount--;
+        }
+
+        @Override
+        public String toString() {
+            return new StringBuilder()
+                    .append("{mResource=")
+                    .append(mResource)
+                    .append(", mRefCount=")
+                    .append(mRefCount)
+                    .append(", mChildren=")
+                    .append(mChildren)
+                    .append("}")
+                    .toString();
+        }
+    }
+
+    /**
+     * Very simple counting class that looks much like a counting semaphore
+     *
+     * <p>This class is not thread-safe, and expects that that users of this class will ensure
+     * synchronization and thread safety by holding the IpSecService.this instance lock.
+     */
+    @VisibleForTesting
+    static class ResourceTracker {
+        private final int mMax;
+        int mCurrent;
+
+        ResourceTracker(int max) {
+            mMax = max;
+            mCurrent = 0;
+        }
+
+        boolean isAvailable() {
+            return (mCurrent < mMax);
+        }
+
+        void take() {
+            if (!isAvailable()) {
+                Log.wtf(TAG, "Too many resources allocated!");
+            }
+            mCurrent++;
+        }
+
+        void give() {
+            if (mCurrent <= 0) {
+                Log.wtf(TAG, "We've released this resource too many times");
+            }
+            mCurrent--;
+        }
+
+        @Override
+        public String toString() {
+            return new StringBuilder()
+                    .append("{mCurrent=")
+                    .append(mCurrent)
+                    .append(", mMax=")
+                    .append(mMax)
+                    .append("}")
+                    .toString();
+        }
+    }
+
+    @VisibleForTesting
+    static final class UserRecord {
+        /* Maximum number of each type of resource that a single UID may possess */
+
+        // Up to 4 active VPNs/IWLAN with potential soft handover.
+        public static final int MAX_NUM_TUNNEL_INTERFACES = 8;
+        public static final int MAX_NUM_ENCAP_SOCKETS = 16;
+
+        // SPIs and Transforms are both cheap, and are 1:1 correlated.
+        public static final int MAX_NUM_TRANSFORMS = 64;
+        public static final int MAX_NUM_SPIS = 64;
+
+        /**
+         * Store each of the OwnedResource types in an (thinly wrapped) sparse array for indexing
+         * and explicit (user) reference management.
+         *
+         * <p>These are stored in separate arrays to improve debuggability and dump output clarity.
+         *
+         * <p>Resources are removed from this array when the user releases their explicit reference
+         * by calling one of the releaseResource() methods.
+         */
+        final RefcountedResourceArray<SpiRecord> mSpiRecords =
+                new RefcountedResourceArray<>(SpiRecord.class.getSimpleName());
+        final RefcountedResourceArray<TransformRecord> mTransformRecords =
+                new RefcountedResourceArray<>(TransformRecord.class.getSimpleName());
+        final RefcountedResourceArray<EncapSocketRecord> mEncapSocketRecords =
+                new RefcountedResourceArray<>(EncapSocketRecord.class.getSimpleName());
+        final RefcountedResourceArray<TunnelInterfaceRecord> mTunnelInterfaceRecords =
+                new RefcountedResourceArray<>(TunnelInterfaceRecord.class.getSimpleName());
+
+        /**
+         * Trackers for quotas for each of the OwnedResource types.
+         *
+         * <p>These trackers are separate from the resource arrays, since they are incremented and
+         * decremented at different points in time. Specifically, quota is only returned upon final
+         * resource deallocation (after all explicit and implicit references are released). Note
+         * that it is possible that calls to releaseResource() will not return the used quota if
+         * there are other resources that depend on (are parents of) the resource being released.
+         */
+        final ResourceTracker mSpiQuotaTracker = new ResourceTracker(MAX_NUM_SPIS);
+        final ResourceTracker mTransformQuotaTracker = new ResourceTracker(MAX_NUM_TRANSFORMS);
+        final ResourceTracker mSocketQuotaTracker = new ResourceTracker(MAX_NUM_ENCAP_SOCKETS);
+        final ResourceTracker mTunnelQuotaTracker = new ResourceTracker(MAX_NUM_TUNNEL_INTERFACES);
+
+        void removeSpiRecord(int resourceId) {
+            mSpiRecords.remove(resourceId);
+        }
+
+        void removeTransformRecord(int resourceId) {
+            mTransformRecords.remove(resourceId);
+        }
+
+        void removeTunnelInterfaceRecord(int resourceId) {
+            mTunnelInterfaceRecords.remove(resourceId);
+        }
+
+        void removeEncapSocketRecord(int resourceId) {
+            mEncapSocketRecords.remove(resourceId);
+        }
+
+        @Override
+        public String toString() {
+            return new StringBuilder()
+                    .append("{mSpiQuotaTracker=")
+                    .append(mSpiQuotaTracker)
+                    .append(", mTransformQuotaTracker=")
+                    .append(mTransformQuotaTracker)
+                    .append(", mSocketQuotaTracker=")
+                    .append(mSocketQuotaTracker)
+                    .append(", mTunnelQuotaTracker=")
+                    .append(mTunnelQuotaTracker)
+                    .append(", mSpiRecords=")
+                    .append(mSpiRecords)
+                    .append(", mTransformRecords=")
+                    .append(mTransformRecords)
+                    .append(", mEncapSocketRecords=")
+                    .append(mEncapSocketRecords)
+                    .append(", mTunnelInterfaceRecords=")
+                    .append(mTunnelInterfaceRecords)
+                    .append("}")
+                    .toString();
+        }
+    }
+
+    /**
+     * This class is not thread-safe, and expects that that users of this class will ensure
+     * synchronization and thread safety by holding the IpSecService.this instance lock.
+     */
+    @VisibleForTesting
+    static final class UserResourceTracker {
+        private final SparseArray<UserRecord> mUserRecords = new SparseArray<>();
+
+        /** Lazy-initialization/getter that populates or retrieves the UserRecord as needed */
+        public UserRecord getUserRecord(int uid) {
+            checkCallerUid(uid);
+
+            UserRecord r = mUserRecords.get(uid);
+            if (r == null) {
+                r = new UserRecord();
+                mUserRecords.put(uid, r);
+            }
+            return r;
+        }
+
+        /** Safety method; guards against access of other user's UserRecords */
+        private void checkCallerUid(int uid) {
+            if (uid != Binder.getCallingUid() && Process.SYSTEM_UID != Binder.getCallingUid()) {
+                throw new SecurityException("Attempted access of unowned resources");
+            }
+        }
+
+        @Override
+        public String toString() {
+            return mUserRecords.toString();
+        }
+    }
+
+    @VisibleForTesting final UserResourceTracker mUserResourceTracker = new UserResourceTracker();
+
+    /**
+     * The OwnedResourceRecord class provides a facility to cleanly and reliably track system
+     * resources. It relies on a provided resourceId that should uniquely identify the kernel
+     * resource. To use this class, the user should implement the invalidate() and
+     * freeUnderlyingResources() methods that are responsible for cleaning up IpSecService resource
+     * tracking arrays and kernel resources, respectively.
+     *
+     * <p>This class associates kernel resources with the UID that owns and controls them.
+     */
+    private abstract class OwnedResourceRecord implements IResource {
+        final int pid;
+        final int uid;
+        protected final int mResourceId;
+
+        OwnedResourceRecord(int resourceId) {
+            super();
+            if (resourceId == INVALID_RESOURCE_ID) {
+                throw new IllegalArgumentException("Resource ID must not be INVALID_RESOURCE_ID");
+            }
+            mResourceId = resourceId;
+            pid = Binder.getCallingPid();
+            uid = Binder.getCallingUid();
+
+            getResourceTracker().take();
+        }
+
+        @Override
+        public abstract void invalidate() throws RemoteException;
+
+        /** Convenience method; retrieves the user resource record for the stored UID. */
+        protected UserRecord getUserRecord() {
+            return mUserResourceTracker.getUserRecord(uid);
+        }
+
+        @Override
+        public abstract void freeUnderlyingResources() throws RemoteException;
+
+        /** Get the resource tracker for this resource */
+        protected abstract ResourceTracker getResourceTracker();
+
+        @Override
+        public String toString() {
+            return new StringBuilder()
+                    .append("{mResourceId=")
+                    .append(mResourceId)
+                    .append(", pid=")
+                    .append(pid)
+                    .append(", uid=")
+                    .append(uid)
+                    .append("}")
+                    .toString();
+        }
+    };
+
+    /**
+     * Thin wrapper over SparseArray to ensure resources exist, and simplify generic typing.
+     *
+     * <p>RefcountedResourceArray prevents null insertions, and throws an IllegalArgumentException
+     * if a key is not found during a retrieval process.
+     */
+    static class RefcountedResourceArray<T extends IResource> {
+        SparseArray<RefcountedResource<T>> mArray = new SparseArray<>();
+        private final String mTypeName;
+
+        public RefcountedResourceArray(String typeName) {
+            this.mTypeName = typeName;
+        }
+
+        /**
+         * Accessor method to get inner resource object.
+         *
+         * @throws IllegalArgumentException if no resource with provided key is found.
+         */
+        T getResourceOrThrow(int key) {
+            return getRefcountedResourceOrThrow(key).getResource();
+        }
+
+        /**
+         * Accessor method to get reference counting wrapper.
+         *
+         * @throws IllegalArgumentException if no resource with provided key is found.
+         */
+        RefcountedResource<T> getRefcountedResourceOrThrow(int key) {
+            RefcountedResource<T> resource = mArray.get(key);
+            if (resource == null) {
+                throw new IllegalArgumentException(
+                        String.format("No such %s found for given id: %d", mTypeName, key));
+            }
+
+            return resource;
+        }
+
+        void put(int key, RefcountedResource<T> obj) {
+            Objects.requireNonNull(obj, "Null resources cannot be added");
+            mArray.put(key, obj);
+        }
+
+        void remove(int key) {
+            mArray.remove(key);
+        }
+
+        @Override
+        public String toString() {
+            return mArray.toString();
+        }
+    }
+
+    /**
+     * Tracks an SA in the kernel, and manages cleanup paths. Once a TransformRecord is
+     * created, the SpiRecord that originally tracked the SAs will reliquish the
+     * responsibility of freeing the underlying SA to this class via the mOwnedByTransform flag.
+     */
+    private final class TransformRecord extends OwnedResourceRecord {
+        private final IpSecConfig mConfig;
+        private final SpiRecord mSpi;
+        private final EncapSocketRecord mSocket;
+
+        TransformRecord(
+                int resourceId, IpSecConfig config, SpiRecord spi, EncapSocketRecord socket) {
+            super(resourceId);
+            mConfig = config;
+            mSpi = spi;
+            mSocket = socket;
+
+            spi.setOwnedByTransform();
+        }
+
+        public IpSecConfig getConfig() {
+            return mConfig;
+        }
+
+        public SpiRecord getSpiRecord() {
+            return mSpi;
+        }
+
+        public EncapSocketRecord getSocketRecord() {
+            return mSocket;
+        }
+
+        /** always guarded by IpSecService#this */
+        @Override
+        public void freeUnderlyingResources() {
+            int spi = mSpi.getSpi();
+            try {
+                mSrvConfig
+                        .getNetdInstance()
+                        .ipSecDeleteSecurityAssociation(
+                                uid,
+                                mConfig.getSourceAddress(),
+                                mConfig.getDestinationAddress(),
+                                spi,
+                                mConfig.getMarkValue(),
+                                mConfig.getMarkMask(),
+                                mConfig.getXfrmInterfaceId());
+            } catch (RemoteException | ServiceSpecificException e) {
+                Log.e(TAG, "Failed to delete SA with ID: " + mResourceId, e);
+            }
+
+            getResourceTracker().give();
+        }
+
+        @Override
+        public void invalidate() throws RemoteException {
+            getUserRecord().removeTransformRecord(mResourceId);
+        }
+
+        @Override
+        protected ResourceTracker getResourceTracker() {
+            return getUserRecord().mTransformQuotaTracker;
+        }
+
+        @Override
+        public String toString() {
+            StringBuilder strBuilder = new StringBuilder();
+            strBuilder
+                    .append("{super=")
+                    .append(super.toString())
+                    .append(", mSocket=")
+                    .append(mSocket)
+                    .append(", mSpi.mResourceId=")
+                    .append(mSpi.mResourceId)
+                    .append(", mConfig=")
+                    .append(mConfig)
+                    .append("}");
+            return strBuilder.toString();
+        }
+    }
+
+    /**
+     * Tracks a single SA in the kernel, and manages cleanup paths. Once used in a Transform, the
+     * responsibility for cleaning up underlying resources will be passed to the TransformRecord
+     * object
+     */
+    private final class SpiRecord extends OwnedResourceRecord {
+        private final String mSourceAddress;
+        private final String mDestinationAddress;
+        private int mSpi;
+
+        private boolean mOwnedByTransform = false;
+
+        SpiRecord(int resourceId, String sourceAddress, String destinationAddress, int spi) {
+            super(resourceId);
+            mSourceAddress = sourceAddress;
+            mDestinationAddress = destinationAddress;
+            mSpi = spi;
+        }
+
+        /** always guarded by IpSecService#this */
+        @Override
+        public void freeUnderlyingResources() {
+            try {
+                if (!mOwnedByTransform) {
+                    mSrvConfig
+                            .getNetdInstance()
+                            .ipSecDeleteSecurityAssociation(
+                                    uid, mSourceAddress, mDestinationAddress, mSpi, 0 /* mark */,
+                                    0 /* mask */, 0 /* if_id */);
+                }
+            } catch (ServiceSpecificException | RemoteException e) {
+                Log.e(TAG, "Failed to delete SPI reservation with ID: " + mResourceId, e);
+            }
+
+            mSpi = IpSecManager.INVALID_SECURITY_PARAMETER_INDEX;
+
+            getResourceTracker().give();
+        }
+
+        public int getSpi() {
+            return mSpi;
+        }
+
+        public String getDestinationAddress() {
+            return mDestinationAddress;
+        }
+
+        public void setOwnedByTransform() {
+            if (mOwnedByTransform) {
+                // Programming error
+                throw new IllegalStateException("Cannot own an SPI twice!");
+            }
+
+            mOwnedByTransform = true;
+        }
+
+        public boolean getOwnedByTransform() {
+            return mOwnedByTransform;
+        }
+
+        @Override
+        public void invalidate() throws RemoteException {
+            getUserRecord().removeSpiRecord(mResourceId);
+        }
+
+        @Override
+        protected ResourceTracker getResourceTracker() {
+            return getUserRecord().mSpiQuotaTracker;
+        }
+
+        @Override
+        public String toString() {
+            StringBuilder strBuilder = new StringBuilder();
+            strBuilder
+                    .append("{super=")
+                    .append(super.toString())
+                    .append(", mSpi=")
+                    .append(mSpi)
+                    .append(", mSourceAddress=")
+                    .append(mSourceAddress)
+                    .append(", mDestinationAddress=")
+                    .append(mDestinationAddress)
+                    .append(", mOwnedByTransform=")
+                    .append(mOwnedByTransform)
+                    .append("}");
+            return strBuilder.toString();
+        }
+    }
+
+    private final SparseBooleanArray mTunnelNetIds = new SparseBooleanArray();
+    final Range<Integer> mNetIdRange = ConnectivityManager.getIpSecNetIdRange();
+    private int mNextTunnelNetId = mNetIdRange.getLower();
+
+    /**
+     * Reserves a netId within the range of netIds allocated for IPsec tunnel interfaces
+     *
+     * <p>This method should only be called from Binder threads. Do not call this from within the
+     * system server as it will crash the system on failure.
+     *
+     * @return an integer key within the netId range, if successful
+     * @throws IllegalStateException if unsuccessful (all netId are currently reserved)
+     */
+    @VisibleForTesting
+    int reserveNetId() {
+        final int range = mNetIdRange.getUpper() - mNetIdRange.getLower() + 1;
+        synchronized (mTunnelNetIds) {
+            for (int i = 0; i < range; i++) {
+                final int netId = mNextTunnelNetId;
+                if (++mNextTunnelNetId > mNetIdRange.getUpper()) {
+                    mNextTunnelNetId = mNetIdRange.getLower();
+                }
+                if (!mTunnelNetIds.get(netId)) {
+                    mTunnelNetIds.put(netId, true);
+                    return netId;
+                }
+            }
+        }
+        throw new IllegalStateException("No free netIds to allocate");
+    }
+
+    @VisibleForTesting
+    void releaseNetId(int netId) {
+        synchronized (mTunnelNetIds) {
+            mTunnelNetIds.delete(netId);
+        }
+    }
+
+    /**
+     * Tracks an tunnel interface, and manages cleanup paths.
+     *
+     * <p>This class is not thread-safe, and expects that that users of this class will ensure
+     * synchronization and thread safety by holding the IpSecService.this instance lock
+     */
+    @VisibleForTesting
+    final class TunnelInterfaceRecord extends OwnedResourceRecord {
+        private final String mInterfaceName;
+
+        // outer addresses
+        private final String mLocalAddress;
+        private final String mRemoteAddress;
+
+        private final int mIkey;
+        private final int mOkey;
+
+        private final int mIfId;
+
+        private Network mUnderlyingNetwork;
+
+        TunnelInterfaceRecord(
+                int resourceId,
+                String interfaceName,
+                Network underlyingNetwork,
+                String localAddr,
+                String remoteAddr,
+                int ikey,
+                int okey,
+                int intfId) {
+            super(resourceId);
+
+            mInterfaceName = interfaceName;
+            mUnderlyingNetwork = underlyingNetwork;
+            mLocalAddress = localAddr;
+            mRemoteAddress = remoteAddr;
+            mIkey = ikey;
+            mOkey = okey;
+            mIfId = intfId;
+        }
+
+        /** always guarded by IpSecService#this */
+        @Override
+        public void freeUnderlyingResources() {
+            // Calls to netd
+            //       Teardown VTI
+            //       Delete global policies
+            try {
+                final INetd netd = mSrvConfig.getNetdInstance();
+                netd.ipSecRemoveTunnelInterface(mInterfaceName);
+
+                for (int selAddrFamily : ADDRESS_FAMILIES) {
+                    netd.ipSecDeleteSecurityPolicy(
+                            uid,
+                            selAddrFamily,
+                            IpSecManager.DIRECTION_OUT,
+                            mOkey,
+                            0xffffffff,
+                            mIfId);
+                    netd.ipSecDeleteSecurityPolicy(
+                            uid,
+                            selAddrFamily,
+                            IpSecManager.DIRECTION_IN,
+                            mIkey,
+                            0xffffffff,
+                            mIfId);
+                }
+            } catch (ServiceSpecificException | RemoteException e) {
+                Log.e(
+                        TAG,
+                        "Failed to delete VTI with interface name: "
+                                + mInterfaceName
+                                + " and id: "
+                                + mResourceId, e);
+            }
+
+            getResourceTracker().give();
+            releaseNetId(mIkey);
+            releaseNetId(mOkey);
+        }
+
+        @GuardedBy("IpSecService.this")
+        public void setUnderlyingNetwork(Network underlyingNetwork) {
+            // When #applyTunnelModeTransform is called, this new underlying network will be used to
+            // update the output mark of the input transform.
+            mUnderlyingNetwork = underlyingNetwork;
+        }
+
+        @GuardedBy("IpSecService.this")
+        public Network getUnderlyingNetwork() {
+            return mUnderlyingNetwork;
+        }
+
+        public String getInterfaceName() {
+            return mInterfaceName;
+        }
+
+        /** Returns the local, outer address for the tunnelInterface */
+        public String getLocalAddress() {
+            return mLocalAddress;
+        }
+
+        /** Returns the remote, outer address for the tunnelInterface */
+        public String getRemoteAddress() {
+            return mRemoteAddress;
+        }
+
+        public int getIkey() {
+            return mIkey;
+        }
+
+        public int getOkey() {
+            return mOkey;
+        }
+
+        public int getIfId() {
+            return mIfId;
+        }
+
+        @Override
+        protected ResourceTracker getResourceTracker() {
+            return getUserRecord().mTunnelQuotaTracker;
+        }
+
+        @Override
+        public void invalidate() {
+            getUserRecord().removeTunnelInterfaceRecord(mResourceId);
+        }
+
+        @Override
+        public String toString() {
+            return new StringBuilder()
+                    .append("{super=")
+                    .append(super.toString())
+                    .append(", mInterfaceName=")
+                    .append(mInterfaceName)
+                    .append(", mUnderlyingNetwork=")
+                    .append(mUnderlyingNetwork)
+                    .append(", mLocalAddress=")
+                    .append(mLocalAddress)
+                    .append(", mRemoteAddress=")
+                    .append(mRemoteAddress)
+                    .append(", mIkey=")
+                    .append(mIkey)
+                    .append(", mOkey=")
+                    .append(mOkey)
+                    .append("}")
+                    .toString();
+        }
+    }
+
+    /**
+     * Tracks a UDP encap socket, and manages cleanup paths
+     *
+     * <p>While this class does not manage non-kernel resources, race conditions around socket
+     * binding require that the service creates the encap socket, binds it and applies the socket
+     * policy before handing it to a user.
+     */
+    private final class EncapSocketRecord extends OwnedResourceRecord {
+        private FileDescriptor mSocket;
+        private final int mPort;
+
+        EncapSocketRecord(int resourceId, FileDescriptor socket, int port) {
+            super(resourceId);
+            mSocket = socket;
+            mPort = port;
+        }
+
+        /** always guarded by IpSecService#this */
+        @Override
+        public void freeUnderlyingResources() {
+            Log.d(TAG, "Closing port " + mPort);
+            IoUtils.closeQuietly(mSocket);
+            mSocket = null;
+
+            getResourceTracker().give();
+        }
+
+        public int getPort() {
+            return mPort;
+        }
+
+        public FileDescriptor getFileDescriptor() {
+            return mSocket;
+        }
+
+        @Override
+        protected ResourceTracker getResourceTracker() {
+            return getUserRecord().mSocketQuotaTracker;
+        }
+
+        @Override
+        public void invalidate() {
+            getUserRecord().removeEncapSocketRecord(mResourceId);
+        }
+
+        @Override
+        public String toString() {
+            return new StringBuilder()
+                    .append("{super=")
+                    .append(super.toString())
+                    .append(", mSocket=")
+                    .append(mSocket)
+                    .append(", mPort=")
+                    .append(mPort)
+                    .append("}")
+                    .toString();
+        }
+    }
+
+    /**
+     * Constructs a new IpSecService instance
+     *
+     * @param context Binder context for this service
+     */
+    private IpSecService(Context context) {
+        this(context, IpSecServiceConfiguration.GETSRVINSTANCE);
+    }
+
+    static IpSecService create(Context context)
+            throws InterruptedException {
+        final IpSecService service = new IpSecService(context);
+        service.connectNativeNetdService();
+        return service;
+    }
+
+    @NonNull
+    private AppOpsManager getAppOpsManager() {
+        AppOpsManager appOps = (AppOpsManager) mContext.getSystemService(Context.APP_OPS_SERVICE);
+        if(appOps == null) throw new RuntimeException("System Server couldn't get AppOps");
+        return appOps;
+    }
+
+    /** @hide */
+    @VisibleForTesting
+    public IpSecService(Context context, IpSecServiceConfiguration config) {
+        this(
+                context,
+                config,
+                (fd, uid) -> {
+                    try {
+                        TrafficStats.setThreadStatsUid(uid);
+                        TrafficStats.tagFileDescriptor(fd);
+                    } finally {
+                        TrafficStats.clearThreadStatsUid();
+                    }
+                });
+    }
+
+    /** @hide */
+    @VisibleForTesting
+    public IpSecService(Context context, IpSecServiceConfiguration config,
+            UidFdTagger uidFdTagger) {
+        mContext = context;
+        mSrvConfig = config;
+        mUidFdTagger = uidFdTagger;
+    }
+
+    public void systemReady() {
+        if (isNetdAlive()) {
+            Log.d(TAG, "IpSecService is ready");
+        } else {
+            Log.wtf(TAG, "IpSecService not ready: failed to connect to NetD Native Service!");
+        }
+    }
+
+    private void connectNativeNetdService() {
+        // Avoid blocking the system server to do this
+        new Thread() {
+            @Override
+            public void run() {
+                synchronized (IpSecService.this) {
+                    NetdService.get(NETD_FETCH_TIMEOUT_MS);
+                }
+            }
+        }.start();
+    }
+
+    synchronized boolean isNetdAlive() {
+        try {
+            final INetd netd = mSrvConfig.getNetdInstance();
+            if (netd == null) {
+                return false;
+            }
+            return netd.isAlive();
+        } catch (RemoteException re) {
+            return false;
+        }
+    }
+
+    /**
+     * Checks that the provided InetAddress is valid for use in an IPsec SA. The address must not be
+     * a wildcard address and must be in a numeric form such as 1.2.3.4 or 2001::1.
+     */
+    private static void checkInetAddress(String inetAddress) {
+        if (TextUtils.isEmpty(inetAddress)) {
+            throw new IllegalArgumentException("Unspecified address");
+        }
+
+        InetAddress checkAddr = InetAddresses.parseNumericAddress(inetAddress);
+
+        if (checkAddr.isAnyLocalAddress()) {
+            throw new IllegalArgumentException("Inappropriate wildcard address: " + inetAddress);
+        }
+    }
+
+    /**
+     * Checks the user-provided direction field and throws an IllegalArgumentException if it is not
+     * DIRECTION_IN or DIRECTION_OUT
+     */
+    private void checkDirection(int direction) {
+        switch (direction) {
+            case IpSecManager.DIRECTION_OUT:
+            case IpSecManager.DIRECTION_IN:
+                return;
+            case IpSecManager.DIRECTION_FWD:
+                // Only NETWORK_STACK or MAINLINE_NETWORK_STACK allowed to use forward policies
+                PermissionUtils.enforceNetworkStackPermission(mContext);
+                return;
+        }
+        throw new IllegalArgumentException("Invalid Direction: " + direction);
+    }
+
+    /** Get a new SPI and maintain the reservation in the system server */
+    @Override
+    public synchronized IpSecSpiResponse allocateSecurityParameterIndex(
+            String destinationAddress, int requestedSpi, IBinder binder) throws RemoteException {
+        checkInetAddress(destinationAddress);
+        // RFC 4303 Section 2.1 - 0=local, 1-255=reserved.
+        if (requestedSpi > 0 && requestedSpi < 256) {
+            throw new IllegalArgumentException("ESP SPI must not be in the range of 0-255.");
+        }
+        Objects.requireNonNull(binder, "Null Binder passed to allocateSecurityParameterIndex");
+
+        int callingUid = Binder.getCallingUid();
+        UserRecord userRecord = mUserResourceTracker.getUserRecord(callingUid);
+        final int resourceId = mNextResourceId++;
+
+        int spi = IpSecManager.INVALID_SECURITY_PARAMETER_INDEX;
+        try {
+            if (!userRecord.mSpiQuotaTracker.isAvailable()) {
+                return new IpSecSpiResponse(
+                        IpSecManager.Status.RESOURCE_UNAVAILABLE, INVALID_RESOURCE_ID, spi);
+            }
+
+            spi =
+                    mSrvConfig
+                            .getNetdInstance()
+                            .ipSecAllocateSpi(callingUid, "", destinationAddress, requestedSpi);
+            Log.d(TAG, "Allocated SPI " + spi);
+            userRecord.mSpiRecords.put(
+                    resourceId,
+                    new RefcountedResource<SpiRecord>(
+                            new SpiRecord(resourceId, "", destinationAddress, spi), binder));
+        } catch (ServiceSpecificException e) {
+            if (e.errorCode == OsConstants.ENOENT) {
+                return new IpSecSpiResponse(
+                        IpSecManager.Status.SPI_UNAVAILABLE, INVALID_RESOURCE_ID, spi);
+            }
+            throw e;
+        } catch (RemoteException e) {
+            throw e.rethrowFromSystemServer();
+        }
+        return new IpSecSpiResponse(IpSecManager.Status.OK, resourceId, spi);
+    }
+
+    /* This method should only be called from Binder threads. Do not call this from
+     * within the system server as it will crash the system on failure.
+     */
+    private void releaseResource(RefcountedResourceArray resArray, int resourceId)
+            throws RemoteException {
+        resArray.getRefcountedResourceOrThrow(resourceId).userRelease();
+    }
+
+    /** Release a previously allocated SPI that has been registered with the system server */
+    @Override
+    public synchronized void releaseSecurityParameterIndex(int resourceId) throws RemoteException {
+        UserRecord userRecord = mUserResourceTracker.getUserRecord(Binder.getCallingUid());
+        releaseResource(userRecord.mSpiRecords, resourceId);
+    }
+
+    /**
+     * This function finds and forcibly binds to a random system port, ensuring that the port cannot
+     * be unbound.
+     *
+     * <p>A socket cannot be un-bound from a port if it was bound to that port by number. To select
+     * a random open port and then bind by number, this function creates a temp socket, binds to a
+     * random port (specifying 0), gets that port number, and then uses is to bind the user's UDP
+     * Encapsulation Socket forcibly, so that it cannot be un-bound by the user with the returned
+     * FileHandle.
+     *
+     * <p>The loop in this function handles the inherent race window between un-binding to a port
+     * and re-binding, during which the system could *technically* hand that port out to someone
+     * else.
+     */
+    private int bindToRandomPort(FileDescriptor sockFd) throws IOException {
+        for (int i = MAX_PORT_BIND_ATTEMPTS; i > 0; i--) {
+            try {
+                FileDescriptor probeSocket = Os.socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
+                Os.bind(probeSocket, INADDR_ANY, 0);
+                int port = ((InetSocketAddress) Os.getsockname(probeSocket)).getPort();
+                Os.close(probeSocket);
+                Log.v(TAG, "Binding to port " + port);
+                Os.bind(sockFd, INADDR_ANY, port);
+                return port;
+            } catch (ErrnoException e) {
+                // Someone miraculously claimed the port just after we closed probeSocket.
+                if (e.errno == OsConstants.EADDRINUSE) {
+                    continue;
+                }
+                throw e.rethrowAsIOException();
+            }
+        }
+        throw new IOException("Failed " + MAX_PORT_BIND_ATTEMPTS + " attempts to bind to a port");
+    }
+
+    /**
+     * Functional interface to do traffic tagging of given sockets to UIDs.
+     *
+     * <p>Specifically used by openUdpEncapsulationSocket to ensure data usage on the UDP encap
+     * sockets are billed to the UID that the UDP encap socket was created on behalf of.
+     *
+     * <p>Separate class so that the socket tagging logic can be mocked; TrafficStats uses static
+     * methods that cannot be easily mocked/tested.
+     */
+    @VisibleForTesting
+    public interface UidFdTagger {
+        /**
+         * Sets socket tag to assign all traffic to the provided UID.
+         *
+         * <p>Since the socket is created on behalf of an unprivileged application, all traffic
+         * should be accounted to the UID of the unprivileged application.
+         */
+        public void tag(FileDescriptor fd, int uid) throws IOException;
+    }
+
+    /**
+     * Open a socket via the system server and bind it to the specified port (random if port=0).
+     * This will return a PFD to the user that represent a bound UDP socket. The system server will
+     * cache the socket and a record of its owner so that it can and must be freed when no longer
+     * needed.
+     */
+    @Override
+    public synchronized IpSecUdpEncapResponse openUdpEncapsulationSocket(int port, IBinder binder)
+            throws RemoteException {
+        if (port != 0 && (port < FREE_PORT_MIN || port > PORT_MAX)) {
+            throw new IllegalArgumentException(
+                    "Specified port number must be a valid non-reserved UDP port");
+        }
+        Objects.requireNonNull(binder, "Null Binder passed to openUdpEncapsulationSocket");
+
+        int callingUid = Binder.getCallingUid();
+        UserRecord userRecord = mUserResourceTracker.getUserRecord(callingUid);
+        final int resourceId = mNextResourceId++;
+        FileDescriptor sockFd = null;
+        try {
+            if (!userRecord.mSocketQuotaTracker.isAvailable()) {
+                return new IpSecUdpEncapResponse(IpSecManager.Status.RESOURCE_UNAVAILABLE);
+            }
+
+            sockFd = Os.socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
+            mUidFdTagger.tag(sockFd, callingUid);
+
+            // This code is common to both the unspecified and specified port cases
+            Os.setsockoptInt(
+                    sockFd,
+                    OsConstants.IPPROTO_UDP,
+                    OsConstants.UDP_ENCAP,
+                    OsConstants.UDP_ENCAP_ESPINUDP);
+
+            mSrvConfig.getNetdInstance().ipSecSetEncapSocketOwner(
+                        new ParcelFileDescriptor(sockFd), callingUid);
+            if (port != 0) {
+                Log.v(TAG, "Binding to port " + port);
+                Os.bind(sockFd, INADDR_ANY, port);
+            } else {
+                port = bindToRandomPort(sockFd);
+            }
+
+            userRecord.mEncapSocketRecords.put(
+                    resourceId,
+                    new RefcountedResource<EncapSocketRecord>(
+                            new EncapSocketRecord(resourceId, sockFd, port), binder));
+            return new IpSecUdpEncapResponse(IpSecManager.Status.OK, resourceId, port, sockFd);
+        } catch (IOException | ErrnoException e) {
+            IoUtils.closeQuietly(sockFd);
+        }
+        // If we make it to here, then something has gone wrong and we couldn't open a socket.
+        // The only reasonable condition that would cause that is resource unavailable.
+        return new IpSecUdpEncapResponse(IpSecManager.Status.RESOURCE_UNAVAILABLE);
+    }
+
+    /** close a socket that has been been allocated by and registered with the system server */
+    @Override
+    public synchronized void closeUdpEncapsulationSocket(int resourceId) throws RemoteException {
+        UserRecord userRecord = mUserResourceTracker.getUserRecord(Binder.getCallingUid());
+        releaseResource(userRecord.mEncapSocketRecords, resourceId);
+    }
+
+    /**
+     * Create a tunnel interface for use in IPSec tunnel mode. The system server will cache the
+     * tunnel interface and a record of its owner so that it can and must be freed when no longer
+     * needed.
+     */
+    @Override
+    public synchronized IpSecTunnelInterfaceResponse createTunnelInterface(
+            String localAddr, String remoteAddr, Network underlyingNetwork, IBinder binder,
+            String callingPackage) {
+        enforceTunnelFeatureAndPermissions(callingPackage);
+        Objects.requireNonNull(binder, "Null Binder passed to createTunnelInterface");
+        Objects.requireNonNull(underlyingNetwork, "No underlying network was specified");
+        checkInetAddress(localAddr);
+        checkInetAddress(remoteAddr);
+
+        // TODO: Check that underlying network exists, and IP addresses not assigned to a different
+        //       network (b/72316676).
+
+        int callerUid = Binder.getCallingUid();
+        UserRecord userRecord = mUserResourceTracker.getUserRecord(callerUid);
+        if (!userRecord.mTunnelQuotaTracker.isAvailable()) {
+            return new IpSecTunnelInterfaceResponse(IpSecManager.Status.RESOURCE_UNAVAILABLE);
+        }
+
+        final int resourceId = mNextResourceId++;
+        final int ikey = reserveNetId();
+        final int okey = reserveNetId();
+        String intfName = String.format("%s%d", INetd.IPSEC_INTERFACE_PREFIX, resourceId);
+
+        try {
+            // Calls to netd:
+            //       Create VTI
+            //       Add inbound/outbound global policies
+            //              (use reqid = 0)
+            final INetd netd = mSrvConfig.getNetdInstance();
+            netd.ipSecAddTunnelInterface(intfName, localAddr, remoteAddr, ikey, okey, resourceId);
+
+            BinderUtils.withCleanCallingIdentity(() -> {
+                NetdUtils.setInterfaceUp(netd, intfName);
+            });
+
+            for (int selAddrFamily : ADDRESS_FAMILIES) {
+                // Always send down correct local/remote addresses for template.
+                netd.ipSecAddSecurityPolicy(
+                        callerUid,
+                        selAddrFamily,
+                        IpSecManager.DIRECTION_OUT,
+                        localAddr,
+                        remoteAddr,
+                        0,
+                        okey,
+                        0xffffffff,
+                        resourceId);
+                netd.ipSecAddSecurityPolicy(
+                        callerUid,
+                        selAddrFamily,
+                        IpSecManager.DIRECTION_IN,
+                        remoteAddr,
+                        localAddr,
+                        0,
+                        ikey,
+                        0xffffffff,
+                        resourceId);
+
+                // Add a forwarding policy on the tunnel interface. In order to support forwarding
+                // the IpSecTunnelInterface must have a forwarding policy matching the incoming SA.
+                //
+                // Unless a IpSecTransform is also applied against this interface in DIRECTION_FWD,
+                // forwarding will be blocked by default (as would be the case if this policy was
+                // absent).
+                //
+                // This is necessary only on the tunnel interface, and not any the interface to
+                // which traffic will be forwarded to.
+                netd.ipSecAddSecurityPolicy(
+                        callerUid,
+                        selAddrFamily,
+                        IpSecManager.DIRECTION_FWD,
+                        remoteAddr,
+                        localAddr,
+                        0,
+                        ikey,
+                        0xffffffff,
+                        resourceId);
+            }
+
+            userRecord.mTunnelInterfaceRecords.put(
+                    resourceId,
+                    new RefcountedResource<TunnelInterfaceRecord>(
+                            new TunnelInterfaceRecord(
+                                    resourceId,
+                                    intfName,
+                                    underlyingNetwork,
+                                    localAddr,
+                                    remoteAddr,
+                                    ikey,
+                                    okey,
+                                    resourceId),
+                            binder));
+            return new IpSecTunnelInterfaceResponse(IpSecManager.Status.OK, resourceId, intfName);
+        } catch (RemoteException e) {
+            // Release keys if we got an error.
+            releaseNetId(ikey);
+            releaseNetId(okey);
+            throw e.rethrowFromSystemServer();
+        } catch (Throwable t) {
+            // Release keys if we got an error.
+            releaseNetId(ikey);
+            releaseNetId(okey);
+            throw t;
+        }
+    }
+
+    /**
+     * Adds a new local address to the tunnel interface. This allows packets to be sent and received
+     * from multiple local IP addresses over the same tunnel.
+     */
+    @Override
+    public synchronized void addAddressToTunnelInterface(
+            int tunnelResourceId, LinkAddress localAddr, String callingPackage) {
+        enforceTunnelFeatureAndPermissions(callingPackage);
+        UserRecord userRecord = mUserResourceTracker.getUserRecord(Binder.getCallingUid());
+
+        // Get tunnelInterface record; if no such interface is found, will throw
+        // IllegalArgumentException
+        TunnelInterfaceRecord tunnelInterfaceInfo =
+                userRecord.mTunnelInterfaceRecords.getResourceOrThrow(tunnelResourceId);
+
+        try {
+            // We can assume general validity of the IP address, since we get them as a
+            // LinkAddress, which does some validation.
+            mSrvConfig
+                    .getNetdInstance()
+                    .interfaceAddAddress(
+                            tunnelInterfaceInfo.mInterfaceName,
+                            localAddr.getAddress().getHostAddress(),
+                            localAddr.getPrefixLength());
+        } catch (RemoteException e) {
+            throw e.rethrowFromSystemServer();
+        }
+    }
+
+    /**
+     * Remove a new local address from the tunnel interface. After removal, the address will no
+     * longer be available to send from, or receive on.
+     */
+    @Override
+    public synchronized void removeAddressFromTunnelInterface(
+            int tunnelResourceId, LinkAddress localAddr, String callingPackage) {
+        enforceTunnelFeatureAndPermissions(callingPackage);
+
+        UserRecord userRecord = mUserResourceTracker.getUserRecord(Binder.getCallingUid());
+        // Get tunnelInterface record; if no such interface is found, will throw
+        // IllegalArgumentException
+        TunnelInterfaceRecord tunnelInterfaceInfo =
+                userRecord.mTunnelInterfaceRecords.getResourceOrThrow(tunnelResourceId);
+
+        try {
+            // We can assume general validity of the IP address, since we get them as a
+            // LinkAddress, which does some validation.
+            mSrvConfig
+                    .getNetdInstance()
+                    .interfaceDelAddress(
+                            tunnelInterfaceInfo.mInterfaceName,
+                            localAddr.getAddress().getHostAddress(),
+                            localAddr.getPrefixLength());
+        } catch (RemoteException e) {
+            throw e.rethrowFromSystemServer();
+        }
+    }
+
+    /** Set TunnelInterface to use a specific underlying network. */
+    @Override
+    public synchronized void setNetworkForTunnelInterface(
+            int tunnelResourceId, Network underlyingNetwork, String callingPackage) {
+        enforceTunnelFeatureAndPermissions(callingPackage);
+        Objects.requireNonNull(underlyingNetwork, "No underlying network was specified");
+
+        final UserRecord userRecord = mUserResourceTracker.getUserRecord(Binder.getCallingUid());
+
+        // Get tunnelInterface record; if no such interface is found, will throw
+        // IllegalArgumentException. userRecord.mTunnelInterfaceRecords is never null
+        final TunnelInterfaceRecord tunnelInterfaceInfo =
+                userRecord.mTunnelInterfaceRecords.getResourceOrThrow(tunnelResourceId);
+
+        final ConnectivityManager connectivityManager =
+                mContext.getSystemService(ConnectivityManager.class);
+        final LinkProperties lp = connectivityManager.getLinkProperties(underlyingNetwork);
+        if (tunnelInterfaceInfo.getInterfaceName().equals(lp.getInterfaceName())) {
+            throw new IllegalArgumentException(
+                    "Underlying network cannot be the network being exposed by this tunnel");
+        }
+
+        // It is meaningless to check if the network exists or is valid because the network might
+        // disconnect at any time after it passes the check.
+
+        tunnelInterfaceInfo.setUnderlyingNetwork(underlyingNetwork);
+    }
+
+    /**
+     * Delete a TunnelInterface that has been been allocated by and registered with the system
+     * server
+     */
+    @Override
+    public synchronized void deleteTunnelInterface(
+            int resourceId, String callingPackage) throws RemoteException {
+        enforceTunnelFeatureAndPermissions(callingPackage);
+        UserRecord userRecord = mUserResourceTracker.getUserRecord(Binder.getCallingUid());
+        releaseResource(userRecord.mTunnelInterfaceRecords, resourceId);
+    }
+
+    @VisibleForTesting
+    void validateAlgorithms(IpSecConfig config) throws IllegalArgumentException {
+        IpSecAlgorithm auth = config.getAuthentication();
+        IpSecAlgorithm crypt = config.getEncryption();
+        IpSecAlgorithm aead = config.getAuthenticatedEncryption();
+
+        // Validate the algorithm set
+        Preconditions.checkArgument(
+                aead != null || crypt != null || auth != null,
+                "No Encryption or Authentication algorithms specified");
+        Preconditions.checkArgument(
+                auth == null || auth.isAuthentication(),
+                "Unsupported algorithm for Authentication");
+        Preconditions.checkArgument(
+                crypt == null || crypt.isEncryption(), "Unsupported algorithm for Encryption");
+        Preconditions.checkArgument(
+                aead == null || aead.isAead(),
+                "Unsupported algorithm for Authenticated Encryption");
+        Preconditions.checkArgument(
+                aead == null || (auth == null && crypt == null),
+                "Authenticated Encryption is mutually exclusive with other Authentication "
+                        + "or Encryption algorithms");
+    }
+
+    private int getFamily(String inetAddress) {
+        int family = AF_UNSPEC;
+        InetAddress checkAddress = InetAddresses.parseNumericAddress(inetAddress);
+        if (checkAddress instanceof Inet4Address) {
+            family = AF_INET;
+        } else if (checkAddress instanceof Inet6Address) {
+            family = AF_INET6;
+        }
+        return family;
+    }
+
+    /**
+     * Checks an IpSecConfig parcel to ensure that the contents are valid and throws an
+     * IllegalArgumentException if they are not.
+     */
+    private void checkIpSecConfig(IpSecConfig config) {
+        UserRecord userRecord = mUserResourceTracker.getUserRecord(Binder.getCallingUid());
+
+        switch (config.getEncapType()) {
+            case IpSecTransform.ENCAP_NONE:
+                break;
+            case IpSecTransform.ENCAP_ESPINUDP:
+            case IpSecTransform.ENCAP_ESPINUDP_NON_IKE:
+                // Retrieve encap socket record; will throw IllegalArgumentException if not found
+                userRecord.mEncapSocketRecords.getResourceOrThrow(
+                        config.getEncapSocketResourceId());
+
+                int port = config.getEncapRemotePort();
+                if (port <= 0 || port > 0xFFFF) {
+                    throw new IllegalArgumentException("Invalid remote UDP port: " + port);
+                }
+                break;
+            default:
+                throw new IllegalArgumentException("Invalid Encap Type: " + config.getEncapType());
+        }
+
+        validateAlgorithms(config);
+
+        // Retrieve SPI record; will throw IllegalArgumentException if not found
+        SpiRecord s = userRecord.mSpiRecords.getResourceOrThrow(config.getSpiResourceId());
+
+        // Check to ensure that SPI has not already been used.
+        if (s.getOwnedByTransform()) {
+            throw new IllegalStateException("SPI already in use; cannot be used in new Transforms");
+        }
+
+        // If no remote address is supplied, then use one from the SPI.
+        if (TextUtils.isEmpty(config.getDestinationAddress())) {
+            config.setDestinationAddress(s.getDestinationAddress());
+        }
+
+        // All remote addresses must match
+        if (!config.getDestinationAddress().equals(s.getDestinationAddress())) {
+            throw new IllegalArgumentException("Mismatched remote addresseses.");
+        }
+
+        // This check is technically redundant due to the chain of custody between the SPI and
+        // the IpSecConfig, but in the future if the dest is allowed to be set explicitly in
+        // the transform, this will prevent us from messing up.
+        checkInetAddress(config.getDestinationAddress());
+
+        // Require a valid source address for all transforms.
+        checkInetAddress(config.getSourceAddress());
+
+        // Check to ensure source and destination have the same address family.
+        String sourceAddress = config.getSourceAddress();
+        String destinationAddress = config.getDestinationAddress();
+        int sourceFamily = getFamily(sourceAddress);
+        int destinationFamily = getFamily(destinationAddress);
+        if (sourceFamily != destinationFamily) {
+            throw new IllegalArgumentException(
+                    "Source address ("
+                            + sourceAddress
+                            + ") and destination address ("
+                            + destinationAddress
+                            + ") have different address families.");
+        }
+
+        // Throw an error if UDP Encapsulation is not used in IPv4.
+        if (config.getEncapType() != IpSecTransform.ENCAP_NONE && sourceFamily != AF_INET) {
+            throw new IllegalArgumentException(
+                    "UDP Encapsulation is not supported for this address family");
+        }
+
+        switch (config.getMode()) {
+            case IpSecTransform.MODE_TRANSPORT:
+                break;
+            case IpSecTransform.MODE_TUNNEL:
+                break;
+            default:
+                throw new IllegalArgumentException(
+                        "Invalid IpSecTransform.mode: " + config.getMode());
+        }
+
+        config.setMarkValue(0);
+        config.setMarkMask(0);
+    }
+
+    private static final String TUNNEL_OP = AppOpsManager.OPSTR_MANAGE_IPSEC_TUNNELS;
+
+    private void enforceTunnelFeatureAndPermissions(String callingPackage) {
+        if (!mContext.getPackageManager().hasSystemFeature(PackageManager.FEATURE_IPSEC_TUNNELS)) {
+            throw new UnsupportedOperationException(
+                    "IPsec Tunnel Mode requires PackageManager.FEATURE_IPSEC_TUNNELS");
+        }
+
+        Objects.requireNonNull(callingPackage, "Null calling package cannot create IpSec tunnels");
+
+        // OP_MANAGE_IPSEC_TUNNELS will return MODE_ERRORED by default, including for the system
+        // server. If the appop is not granted, require that the caller has the MANAGE_IPSEC_TUNNELS
+        // permission or is the System Server.
+        if (AppOpsManager.MODE_ALLOWED == getAppOpsManager().noteOpNoThrow(
+                TUNNEL_OP, Binder.getCallingUid(), callingPackage)) {
+            return;
+        }
+        mContext.enforceCallingOrSelfPermission(
+                android.Manifest.permission.MANAGE_IPSEC_TUNNELS, "IpSecService");
+    }
+
+    private void createOrUpdateTransform(
+            IpSecConfig c, int resourceId, SpiRecord spiRecord, EncapSocketRecord socketRecord)
+            throws RemoteException {
+
+        int encapType = c.getEncapType(), encapLocalPort = 0, encapRemotePort = 0;
+        if (encapType != IpSecTransform.ENCAP_NONE) {
+            encapLocalPort = socketRecord.getPort();
+            encapRemotePort = c.getEncapRemotePort();
+        }
+
+        IpSecAlgorithm auth = c.getAuthentication();
+        IpSecAlgorithm crypt = c.getEncryption();
+        IpSecAlgorithm authCrypt = c.getAuthenticatedEncryption();
+
+        String cryptName;
+        if (crypt == null) {
+            cryptName = (authCrypt == null) ? IpSecAlgorithm.CRYPT_NULL : "";
+        } else {
+            cryptName = crypt.getName();
+        }
+
+        mSrvConfig
+                .getNetdInstance()
+                .ipSecAddSecurityAssociation(
+                        Binder.getCallingUid(),
+                        c.getMode(),
+                        c.getSourceAddress(),
+                        c.getDestinationAddress(),
+                        (c.getNetwork() != null) ? c.getNetwork().getNetId() : 0,
+                        spiRecord.getSpi(),
+                        c.getMarkValue(),
+                        c.getMarkMask(),
+                        (auth != null) ? auth.getName() : "",
+                        (auth != null) ? auth.getKey() : new byte[] {},
+                        (auth != null) ? auth.getTruncationLengthBits() : 0,
+                        cryptName,
+                        (crypt != null) ? crypt.getKey() : new byte[] {},
+                        (crypt != null) ? crypt.getTruncationLengthBits() : 0,
+                        (authCrypt != null) ? authCrypt.getName() : "",
+                        (authCrypt != null) ? authCrypt.getKey() : new byte[] {},
+                        (authCrypt != null) ? authCrypt.getTruncationLengthBits() : 0,
+                        encapType,
+                        encapLocalPort,
+                        encapRemotePort,
+                        c.getXfrmInterfaceId());
+    }
+
+    /**
+     * Create a IPsec transform, which represents a single security association in the kernel. The
+     * transform will be cached by the system server and must be freed when no longer needed. It is
+     * possible to free one, deleting the SA from underneath sockets that are using it, which will
+     * result in all of those sockets becoming unable to send or receive data.
+     */
+    @Override
+    public synchronized IpSecTransformResponse createTransform(
+            IpSecConfig c, IBinder binder, String callingPackage) throws RemoteException {
+        Objects.requireNonNull(c);
+        if (c.getMode() == IpSecTransform.MODE_TUNNEL) {
+            enforceTunnelFeatureAndPermissions(callingPackage);
+        }
+        checkIpSecConfig(c);
+        Objects.requireNonNull(binder, "Null Binder passed to createTransform");
+        final int resourceId = mNextResourceId++;
+
+        UserRecord userRecord = mUserResourceTracker.getUserRecord(Binder.getCallingUid());
+        List<RefcountedResource> dependencies = new ArrayList<>();
+
+        if (!userRecord.mTransformQuotaTracker.isAvailable()) {
+            return new IpSecTransformResponse(IpSecManager.Status.RESOURCE_UNAVAILABLE);
+        }
+
+        EncapSocketRecord socketRecord = null;
+        if (c.getEncapType() != IpSecTransform.ENCAP_NONE) {
+            RefcountedResource<EncapSocketRecord> refcountedSocketRecord =
+                    userRecord.mEncapSocketRecords.getRefcountedResourceOrThrow(
+                            c.getEncapSocketResourceId());
+            dependencies.add(refcountedSocketRecord);
+            socketRecord = refcountedSocketRecord.getResource();
+        }
+
+        RefcountedResource<SpiRecord> refcountedSpiRecord =
+                userRecord.mSpiRecords.getRefcountedResourceOrThrow(c.getSpiResourceId());
+        dependencies.add(refcountedSpiRecord);
+        SpiRecord spiRecord = refcountedSpiRecord.getResource();
+
+        createOrUpdateTransform(c, resourceId, spiRecord, socketRecord);
+
+        // SA was created successfully, time to construct a record and lock it away
+        userRecord.mTransformRecords.put(
+                resourceId,
+                new RefcountedResource<TransformRecord>(
+                        new TransformRecord(resourceId, c, spiRecord, socketRecord),
+                        binder,
+                        dependencies.toArray(new RefcountedResource[dependencies.size()])));
+        return new IpSecTransformResponse(IpSecManager.Status.OK, resourceId);
+    }
+
+    /**
+     * Delete a transport mode transform that was previously allocated by + registered with the
+     * system server. If this is called on an inactive (or non-existent) transform, it will not
+     * return an error. It's safe to de-allocate transforms that may have already been deleted for
+     * other reasons.
+     */
+    @Override
+    public synchronized void deleteTransform(int resourceId) throws RemoteException {
+        UserRecord userRecord = mUserResourceTracker.getUserRecord(Binder.getCallingUid());
+        releaseResource(userRecord.mTransformRecords, resourceId);
+    }
+
+    /**
+     * Apply an active transport mode transform to a socket, which will apply the IPsec security
+     * association as a correspondent policy to the provided socket
+     */
+    @Override
+    public synchronized void applyTransportModeTransform(
+            ParcelFileDescriptor socket, int direction, int resourceId) throws RemoteException {
+        int callingUid = Binder.getCallingUid();
+        UserRecord userRecord = mUserResourceTracker.getUserRecord(callingUid);
+        checkDirection(direction);
+        // Get transform record; if no transform is found, will throw IllegalArgumentException
+        TransformRecord info = userRecord.mTransformRecords.getResourceOrThrow(resourceId);
+
+        // TODO: make this a function.
+        if (info.pid != getCallingPid() || info.uid != callingUid) {
+            throw new SecurityException("Only the owner of an IpSec Transform may apply it!");
+        }
+
+        // Get config and check that to-be-applied transform has the correct mode
+        IpSecConfig c = info.getConfig();
+        Preconditions.checkArgument(
+                c.getMode() == IpSecTransform.MODE_TRANSPORT,
+                "Transform mode was not Transport mode; cannot be applied to a socket");
+
+        mSrvConfig
+                .getNetdInstance()
+                .ipSecApplyTransportModeTransform(
+                        socket,
+                        callingUid,
+                        direction,
+                        c.getSourceAddress(),
+                        c.getDestinationAddress(),
+                        info.getSpiRecord().getSpi());
+    }
+
+    /**
+     * Remove transport mode transforms from a socket, applying the default (empty) policy. This
+     * ensures that NO IPsec policy is applied to the socket (would be the equivalent of applying a
+     * policy that performs no IPsec). Today the resourceId parameter is passed but not used:
+     * reserved for future improved input validation.
+     */
+    @Override
+    public synchronized void removeTransportModeTransforms(ParcelFileDescriptor socket)
+            throws RemoteException {
+        mSrvConfig
+                .getNetdInstance()
+                .ipSecRemoveTransportModeTransform(socket);
+    }
+
+    /**
+     * Apply an active tunnel mode transform to a TunnelInterface, which will apply the IPsec
+     * security association as a correspondent policy to the provided interface
+     */
+    @Override
+    public synchronized void applyTunnelModeTransform(
+            int tunnelResourceId, int direction,
+            int transformResourceId, String callingPackage) throws RemoteException {
+        enforceTunnelFeatureAndPermissions(callingPackage);
+        checkDirection(direction);
+
+        int callingUid = Binder.getCallingUid();
+        UserRecord userRecord = mUserResourceTracker.getUserRecord(callingUid);
+
+        // Get transform record; if no transform is found, will throw IllegalArgumentException
+        TransformRecord transformInfo =
+                userRecord.mTransformRecords.getResourceOrThrow(transformResourceId);
+
+        // Get tunnelInterface record; if no such interface is found, will throw
+        // IllegalArgumentException
+        TunnelInterfaceRecord tunnelInterfaceInfo =
+                userRecord.mTunnelInterfaceRecords.getResourceOrThrow(tunnelResourceId);
+
+        // Get config and check that to-be-applied transform has the correct mode
+        IpSecConfig c = transformInfo.getConfig();
+        Preconditions.checkArgument(
+                c.getMode() == IpSecTransform.MODE_TUNNEL,
+                "Transform mode was not Tunnel mode; cannot be applied to a tunnel interface");
+
+        EncapSocketRecord socketRecord = null;
+        if (c.getEncapType() != IpSecTransform.ENCAP_NONE) {
+            socketRecord =
+                    userRecord.mEncapSocketRecords.getResourceOrThrow(c.getEncapSocketResourceId());
+        }
+        SpiRecord spiRecord = transformInfo.getSpiRecord();
+
+        int mark =
+                (direction == IpSecManager.DIRECTION_OUT)
+                        ? tunnelInterfaceInfo.getOkey()
+                        : tunnelInterfaceInfo.getIkey(); // Ikey also used for FWD policies
+
+        try {
+            // Default to using the invalid SPI of 0 for inbound SAs. This allows policies to skip
+            // SPI matching as part of the template resolution.
+            int spi = IpSecManager.INVALID_SECURITY_PARAMETER_INDEX;
+            c.setXfrmInterfaceId(tunnelInterfaceInfo.getIfId());
+
+            // TODO: enable this when UPDSA supports updating marks. Adding kernel support upstream
+            //     (and backporting) would allow us to narrow the mark space, and ensure that the SA
+            //     and SPs have matching marks (as VTI are meant to be built).
+            // Currently update does nothing with marks. Leave empty (defaulting to 0) to ensure the
+            //     config matches the actual allocated resources in the kernel.
+            // All SAs will have zero marks (from creation time), and any policy that matches the
+            //     same src/dst could match these SAs. Non-IpSecService governed processes that
+            //     establish floating policies with the same src/dst may result in undefined
+            //     behavior. This is generally limited to vendor code due to the permissions
+            //     (CAP_NET_ADMIN) required.
+            //
+            // c.setMarkValue(mark);
+            // c.setMarkMask(0xffffffff);
+
+            if (direction == IpSecManager.DIRECTION_OUT) {
+                // Set output mark via underlying network (output only)
+                c.setNetwork(tunnelInterfaceInfo.getUnderlyingNetwork());
+
+                // Set outbound SPI only. We want inbound to use any valid SA (old, new) on rekeys,
+                // but want to guarantee outbound packets are sent over the new SA.
+                spi = spiRecord.getSpi();
+            }
+
+            // Always update the policy with the relevant XFRM_IF_ID
+            for (int selAddrFamily : ADDRESS_FAMILIES) {
+                mSrvConfig
+                        .getNetdInstance()
+                        .ipSecUpdateSecurityPolicy(
+                                callingUid,
+                                selAddrFamily,
+                                direction,
+                                transformInfo.getConfig().getSourceAddress(),
+                                transformInfo.getConfig().getDestinationAddress(),
+                                spi, // If outbound, also add SPI to the policy.
+                                mark, // Must always set policy mark; ikey/okey for VTIs
+                                0xffffffff,
+                                c.getXfrmInterfaceId());
+            }
+
+            // Update SA with tunnel mark (ikey or okey based on direction)
+            createOrUpdateTransform(c, transformResourceId, spiRecord, socketRecord);
+        } catch (ServiceSpecificException e) {
+            if (e.errorCode == EINVAL) {
+                throw new IllegalArgumentException(e.toString());
+            } else {
+                throw e;
+            }
+        }
+    }
+
+    @Override
+    protected synchronized void dump(FileDescriptor fd, PrintWriter pw, String[] args) {
+        mContext.enforceCallingOrSelfPermission(DUMP, TAG);
+
+        pw.println("IpSecService dump:");
+        pw.println("NetdNativeService Connection: " + (isNetdAlive() ? "alive" : "dead"));
+        pw.println();
+
+        pw.println("mUserResourceTracker:");
+        pw.println(mUserResourceTracker);
+    }
+}