Hidden SipTransport API definition

The SipTransport API definition, which is being put in using @hide
in order to allow applications to review and build testing around
the definitions.

In Follow up CLs, the APIs will be backed by the appropriate AIDLs
and will gradually start being moved to @SystemApi as they are
implemented and CTS tests are added

Test: CTS, docs review
Bug: 154763999
Change-Id: I5266eb7c077299c5e7a8c7780db6a30fffdfc556

15 files changed, 2113 insertions, 10 deletions

diff --git a/telephony/java/android/telephony/ImsManager.java b/telephony/java/android/telephony/ImsManager.java
index 28feab27a794..13f407b14f01 100644
--- a/telephony/java/android/telephony/ImsManager.java
+++ b/telephony/java/android/telephony/ImsManager.java
@@ -128,13 +128,15 @@ public class ImsManager {
     }
 
     /**
-     * Create an instance of SipDelegateManager for the subscription id specified.
+     * Create an instance of {@link SipDelegateManager} for the subscription id specified.
      * <p>
-     * Used for RCS single registration cases, where an IMS application needs to forward SIP
-     * traffic through the device's IMS service.
-     * @param subscriptionId The ID of the subscription that this SipDelegateManager will use.
+     * Allows an IMS application to forward SIP traffic through the device's IMS service,
+     * which is used for cellular carriers that require the device to share a single IMS
+     * registration for both MMTEL and RCS features.
+     * @param subscriptionId The ID of the subscription that this {@link SipDelegateManager} will
+     *                       be bound to.
      * @throws IllegalArgumentException if the subscription is invalid.
-     * @return a SipDelegateManager instance for the specified subscription ID.
+     * @return a {@link SipDelegateManager} instance for the specified subscription ID.
      * @hide
      */
     @SystemApi
diff --git a/telephony/java/android/telephony/ims/DelegateMessageCallback.java b/telephony/java/android/telephony/ims/DelegateMessageCallback.java
new file mode 100644
index 000000000000..beec4a680d78
--- /dev/null
+++ b/telephony/java/android/telephony/ims/DelegateMessageCallback.java
@@ -0,0 +1,59 @@
+/*
+ * Copyright (C) 2020 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.telephony.ims;
+
+import android.annotation.NonNull;
+import android.telephony.ims.stub.SipDelegate;
+
+/**
+ * Callback interface provided to the SipTransport implementation to notify a remote application of
+ * the following:
+ * <ul>
+ *     <li>A new incoming SIP message associated with the feature tags the SipDelegate registered
+ *     with has been received or an in-dialog request to this SipDelegate has been received.</li>
+ *     <li>Acknowledge that an outgoing SIP message from the RCS application has been sent
+ *     successfully or notify the application of the reason why it was not sent</li>
+ * </ul>
+ * @hide
+ */
+public interface DelegateMessageCallback {
+
+    /**
+     * Send a new incoming SIP message to the remote application for processing.
+     */
+    void onMessageReceived(@NonNull SipMessage message);
+
+    /**
+     * Notify the remote application that a previous request to send a SIP message using
+     * {@link SipDelegate#sendMessage} has succeeded.
+     *
+     * @param viaTransactionId The transaction ID found in the via header field of the
+     *         previously sent {@link SipMessage}.
+     */
+    void onMessageSent(@NonNull String viaTransactionId);
+
+    /**
+     * Notify the remote application that a previous request to send a SIP message using
+     * {@link SipDelegate#sendMessage} has failed.
+     *
+     * @param viaTransactionId The Transaction ID found in the via header field of the previously
+     *         sent {@link SipMessage}.
+     * @param reason The reason for the failure.
+     */
+    void onMessageSendFailure(@NonNull String viaTransactionId,
+            @SipDelegateManager.MessageFailureReason int reason);
+}
diff --git a/telephony/java/android/telephony/ims/DelegateRegistrationState.java b/telephony/java/android/telephony/ims/DelegateRegistrationState.java
new file mode 100644
index 000000000000..4facfa77de21
--- /dev/null
+++ b/telephony/java/android/telephony/ims/DelegateRegistrationState.java
@@ -0,0 +1,327 @@
+/*
+ * Copyright (C) 2020 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.telephony.ims;
+
+import android.annotation.IntDef;
+import android.annotation.NonNull;
+import android.os.Parcel;
+import android.os.Parcelable;
+import android.util.ArraySet;
+
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Objects;
+import java.util.Set;
+
+/**
+ * Contains the full state of the IMS feature tags associated with a SipDelegate and managed by the
+ * ImsService.
+ * @hide
+ */
+public final class DelegateRegistrationState implements Parcelable {
+
+    /**
+     * This feature tag has been deregistered for an unknown reason. Outgoing out-of-dialog SIP
+     * messages associated with feature tags that are not registered will fail.
+     */
+    public static final int DEREGISTERED_REASON_UNKNOWN = 0;
+
+    /**
+     * This feature tag has been deregistered because it is not provisioned to be used on this radio
+     * access technology or PDN. Outgoing out-of-dialog SIP messages associated with feature tags
+     * that are not registered will fail.
+     * <p>
+     * There may be new incoming SIP dialog requests on a feature that that is not provisioned. It
+     * is still expected that the SipDelegateConnection responds to the request.
+     */
+    public static final int DEREGISTERED_REASON_NOT_PROVISIONED = 1;
+
+    /**
+     * This feature tag has been deregistered because IMS has been deregistered. All outgoing SIP
+     * messages will fail until IMS registration occurs.
+     */
+    public static final int DEREGISTERED_REASON_NOT_REGISTERED = 2;
+
+    /**
+     * This feature tag is being deregistered because the PDN that the IMS registration is on is
+     *changing.
+     * All open SIP dialogs need to be closed before the PDN change can proceed.
+     */
+    public static final int DEREGISTERING_REASON_PDN_CHANGE = 3;
+
+    /**
+     * This feature tag is being deregistered due to a provisioning change. This can be triggered by
+     * many things, such as a provisioning change triggered by the carrier network, a radio access
+     * technology change by the modem causing a different set of feature tags to be provisioned, or
+     * a user triggered hange, such as data being enabled/disabled.
+     * <p>
+     * All open SIP dialogs associated with the new deprovisioned feature tag need to be closed
+     * before the IMS registration modification can proceed.
+     */
+    public static final int DEREGISTERING_REASON_PROVISIONING_CHANGE = 4;
+
+    /**
+     * This feature tag is deregistering because the SipDelegate associated with this feature tag
+     * needs to change its supported feature set.
+     * <p>
+     * All open SIP Dialogs associated with this feature tag must be closed before this operation
+     * can proceed.
+     */
+    public static final int DEREGISTERING_REASON_FEATURE_TAGS_CHANGING = 5;
+
+    /**
+     * This feature tag is deregistering because the SipDelegate is in the process of being
+     * destroyed.
+     * <p>
+     * All open SIP Dialogs associated with this feature tag must be closed before this operation
+     * can proceed.
+     */
+    public static final int DEREGISTERING_REASON_DESTROY_PENDING = 6;
+
+    /** @hide */
+    @Retention(RetentionPolicy.SOURCE)
+    @IntDef(prefix = "DEREGISTERED_REASON_", value = {
+            DEREGISTERED_REASON_UNKNOWN,
+            DEREGISTERED_REASON_NOT_PROVISIONED,
+            DEREGISTERED_REASON_NOT_REGISTERED
+    })
+    public @interface DeregisteredReason {}
+
+
+    /** @hide */
+    @Retention(RetentionPolicy.SOURCE)
+    @IntDef(prefix = "DEREGISTERING_REASON_", value = {
+            DEREGISTERING_REASON_PDN_CHANGE,
+            DEREGISTERING_REASON_PROVISIONING_CHANGE,
+            DEREGISTERING_REASON_FEATURE_TAGS_CHANGING,
+            DEREGISTERING_REASON_DESTROY_PENDING
+    })
+    public @interface DeregisteringReason {}
+
+    private final ArrayList<String> mRegisteredTags = new ArrayList<>();
+    private final ArrayList<FeatureTagState> mDeregisteringTags = new ArrayList<>();
+    private final ArrayList<FeatureTagState> mDeregisteredTags = new ArrayList<>();
+
+    /**
+     * Builder used to create new instances of {@link DelegateRegistrationState}.
+     */
+    public static class Builder {
+
+        private final DelegateRegistrationState mState;
+
+        /* Create a new instance of {@link Builder} */
+        public Builder() {
+            mState = new DelegateRegistrationState();
+        }
+
+        /**
+         * Add a feature tag that is currently included in the current network IMS Registration.
+         * @param featureTag The IMS media feature tag included in the current IMS registration.
+         * @return The in-progress Builder instance for RegistrationState.
+         */
+        public Builder addRegisteredFeatureTag(@NonNull String featureTag) {
+            if (!mState.mRegisteredTags.contains(featureTag)) {
+                mState.mRegisteredTags.add(featureTag);
+            }
+            return this;
+        }
+
+        /**
+         * Add a list of feature tags that are currently included in the current network IMS
+         * Registration.
+         * @param featureTags The IMS media feature tags included in the current IMS registration.
+         * @return The in-progress Builder instance for RegistrationState.
+         */
+        public Builder addRegisteredFeatureTags(@NonNull Set<String> featureTags) {
+            mState.mRegisteredTags.addAll(featureTags);
+            return this;
+        }
+
+        /**
+         * Add a feature tag that is in the current network IMS Registration, but is in the progress
+         * of being deregistered and requires action from the RCS application before the IMS
+         * registration can be modified.
+         *
+         * See {@link DeregisteringReason} for more information regarding what is required by the
+         * RCS application to proceed.
+         *
+         * @param featureTag The media feature tag that has limited or no availability due to its
+         *         current deregistering state.
+         * @param reason The reason why the media feature tag has moved to the deregistering state.
+         *         The availability of the feature tag depends on the {@link DeregisteringReason}.
+         * @return The in-progress Builder instance for RegistrationState.
+         */
+        public Builder addDeregisteringFeatureTag(@NonNull String featureTag,
+                @DeregisteringReason int reason) {
+            boolean ftExists = mState.mDeregisteringTags.stream().anyMatch(
+                    f -> f.getFeatureTag().equals(featureTag));
+            if (!ftExists) {
+                mState.mDeregisteringTags.add(new FeatureTagState(featureTag, reason));
+            }
+            return this;
+        }
+
+        /**
+         * Add a feature tag that is currently not included in the network RCS registration. See
+         * {@link DeregisteredReason} for more information regarding the reason for why the feature
+         * tag is not registered.
+         * @param featureTag The media feature tag that is not registered.
+         * @param reason The reason why the media feature tag has been deregistered.
+         * @return The in-progress Builder instance for RegistrationState.
+         */
+        public Builder addDeregisteredFeatureTag(@NonNull String featureTag,
+                @DeregisteredReason int reason) {
+            boolean ftExists = mState.mDeregisteredTags.stream().anyMatch(
+                    f -> f.getFeatureTag().equals(featureTag));
+            if (!ftExists) {
+                mState.mDeregisteredTags.add(new FeatureTagState(featureTag, reason));
+            }
+            return this;
+        }
+
+        /**
+         * @return the finalized instance.
+         */
+        public DelegateRegistrationState build() {
+            return mState;
+        }
+    }
+
+    /**
+     * The builder should be used to construct a new instance of this class.
+     */
+    private DelegateRegistrationState() {}
+
+    /**
+     * Used for unparcelling only.
+     */
+    private DelegateRegistrationState(Parcel source) {
+        source.readList(mRegisteredTags, null /*classloader*/);
+        readStateFromParcel(source, mDeregisteringTags);
+        readStateFromParcel(source, mDeregisteredTags);
+    }
+
+    /**
+     * Get the feature tags that this SipDelegate is associated with that are currently part of the
+     * network IMS registration. SIP Messages both in and out of a SIP Dialog may be sent and
+     * received using these feature tags.
+     * @return A Set of feature tags that the SipDelegate has associated with that are included in
+     * the network IMS registration.
+     */
+    public @NonNull Set<String> getRegisteredFeatureTags() {
+        return new ArraySet<>(mRegisteredTags);
+    }
+
+    /**
+     * Get the feature tags that this SipDelegate is associated with that are currently part of the
+     * network IMS registration but are in the process of being deregistered.
+     * <p>
+     * Any incoming SIP messages associated with a feature tag included in this list will still be
+     * delivered. Outgoing SIP messages that are still in-dialog will be delivered to the
+     * SipDelegate, but outgoing out-of-dialog SIP messages with  a feature tag that is included in
+     * this list will fail.
+     * <p>
+     * The SipDelegate will stay in this state for a limited period of time while it waits for the
+     * RCS application to perform a specific action. More details on the actions that can cause this
+     * state as well as the expected response are included in the reason codes and can be found in
+     * {@link DeregisteringReason}.
+     * @return A Set of feature tags that the SipDelegate has associated with that are included in
+     * the network IMS registration but are in the process of deregistering.
+     */
+    public @NonNull Set<FeatureTagState> getDeregisteringFeatureTags() {
+        return new ArraySet<>(mDeregisteringTags);
+    }
+
+    /**
+     * Get the list of feature tags that are associated with this SipDelegate but are not currently
+     * included in the network IMS registration.
+     * <p>
+     * See {@link DeregisteredReason} codes for more information related to the reasons why this may
+     * occur.
+     * <p>
+     * Due to network race conditions, there may still be onditions where an incoming out-of-dialog
+     * SIP message is delivered for a feature tag that is considered deregistered. Due to this
+     * condition, in-dialog outgoing SIP messages for deregistered feature tags will still be
+     * allowed as long as they are in response to a dialog started by a remote party. Any outgoing
+     * out-of-dialog SIP messages associated with feature tags included in this list will fail to be
+     * sent.
+     * @return A list of feature tags that the SipDelegate has associated with that not included in
+     * the network IMS registration.
+     */
+    public @NonNull Set<FeatureTagState> getDeregisteredFeatureTags() {
+        return new ArraySet<>(mDeregisteredTags);
+    }
+
+    public static final Creator<DelegateRegistrationState> CREATOR =
+            new Creator<DelegateRegistrationState>() {
+        @Override
+        public DelegateRegistrationState createFromParcel(Parcel source) {
+            return new DelegateRegistrationState(source);
+        }
+
+        @Override
+        public DelegateRegistrationState[] newArray(int size) {
+            return new DelegateRegistrationState[size];
+        }
+    };
+
+    @Override
+    public int describeContents() {
+        return 0;
+    }
+
+    @Override
+    public void writeToParcel(Parcel dest, int flags) {
+        dest.writeList(mRegisteredTags);
+        writeStateToParcel(dest, mDeregisteringTags);
+        writeStateToParcel(dest, mDeregisteredTags);
+    }
+
+    private void writeStateToParcel(Parcel dest, List<FeatureTagState> state) {
+        dest.writeInt(state.size());
+        for (FeatureTagState s : state) {
+            dest.writeString(s.getFeatureTag());
+            dest.writeInt(s.getState());
+        }
+    }
+
+    private void readStateFromParcel(Parcel source, List<FeatureTagState> emptyState) {
+        int len = source.readInt();
+        for (int i = 0; i < len; i++) {
+            String ft = source.readString();
+            int reason = source.readInt();
+            emptyState.add(new FeatureTagState(ft, reason));
+        }
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+        DelegateRegistrationState that = (DelegateRegistrationState) o;
+        return mRegisteredTags.equals(that.mRegisteredTags)
+                && mDeregisteringTags.equals(that.mDeregisteringTags)
+                && mDeregisteredTags.equals(that.mDeregisteredTags);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(mRegisteredTags, mDeregisteringTags, mDeregisteredTags);
+    }
+}
diff --git a/telephony/java/android/telephony/ims/DelegateRequest.java b/telephony/java/android/telephony/ims/DelegateRequest.java
new file mode 100644
index 000000000000..f384901d58bd
--- /dev/null
+++ b/telephony/java/android/telephony/ims/DelegateRequest.java
@@ -0,0 +1,101 @@
+/*
+ * Copyright (C) 2020 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.telephony.ims;
+
+import android.annotation.NonNull;
+import android.os.Parcel;
+import android.os.Parcelable;
+import android.telephony.ims.stub.SipDelegate;
+import android.util.ArraySet;
+
+import java.util.ArrayList;
+import java.util.Objects;
+import java.util.Set;
+
+/**
+ * Contains information required for the creation of a {@link SipDelegate} and the associated
+ * SipDelegateConnection given back to the requesting application.
+ * @hide
+ */
+public final class DelegateRequest implements Parcelable {
+
+    private final ArrayList<String> mFeatureTags;
+
+    /**
+     * Create a new DelegateRequest, which will be used to create a SipDelegate by the ImsService.
+     * @param featureTags The list of IMS feature tags that will be associated with the SipDelegate
+     *                    created using this DelegateRequest. All feature tags are expected to be in
+     *                    the format defined in RCC.07 section 2.6.1.3.
+     */
+    public DelegateRequest(@NonNull Set<String> featureTags) {
+        if (featureTags == null) {
+            throw new IllegalStateException("Invalid arguments, featureTags List can not be null");
+        }
+        mFeatureTags = new ArrayList<>(featureTags);
+    }
+
+    /**
+     * @return the list of IMS feature tag associated with this DelegateRequest in the format
+     * defined in RCC.07 section 2.6.1.3.
+     */
+    public Set<String> getFeatureTags() {
+        return new ArraySet<>(mFeatureTags);
+    }
+
+    /**
+     * Internal constructor used only for unparcelling.
+     */
+    private DelegateRequest(Parcel in) {
+        mFeatureTags = new ArrayList<>();
+        in.readList(mFeatureTags, null /*classLoader*/);
+    }
+
+    @Override
+    public int describeContents() {
+        return 0;
+    }
+
+    @Override
+    public void writeToParcel(Parcel dest, int flags) {
+        dest.writeList(mFeatureTags);
+    }
+
+    public static final @NonNull Creator<DelegateRequest> CREATOR = new Creator<DelegateRequest>() {
+        @Override
+        public DelegateRequest createFromParcel(Parcel source) {
+            return new DelegateRequest(source);
+        }
+
+        @Override
+        public DelegateRequest[] newArray(int size) {
+            return new DelegateRequest[size];
+        }
+    };
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+        DelegateRequest that = (DelegateRequest) o;
+        return mFeatureTags.equals(that.mFeatureTags);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(mFeatureTags);
+    }
+}
diff --git a/telephony/java/android/telephony/ims/DelegateStateCallback.java b/telephony/java/android/telephony/ims/DelegateStateCallback.java
new file mode 100644
index 000000000000..0f1afc42249e
--- /dev/null
+++ b/telephony/java/android/telephony/ims/DelegateStateCallback.java
@@ -0,0 +1,101 @@
+/*
+ * Copyright (C) 2020 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.telephony.ims;
+
+import android.annotation.NonNull;
+import android.annotation.Nullable;
+import android.telephony.ims.stub.SipDelegate;
+import android.telephony.ims.stub.SipTransportImplBase;
+
+import java.util.List;
+
+/**
+ * Callback interface to notify a remote application of the following:
+ * <ul>
+ *     <li>the {@link SipDelegate} associated with this callback has been created or destroyed in
+ *         response to a creation or destruction request from the framework</li>
+ *     <li>the SIP IMS configuration associated with this {@link SipDelegate} has changed</li>
+ *     <li>the IMS registration of the feature tags associated with this {@link SipDelegate} have
+ *         changed.</li>
+ * </ul>
+ * @hide
+ */
+public interface DelegateStateCallback {
+
+    /**
+     * This must be called by the ImsService after {@link SipTransportImplBase#createSipDelegate} is
+     * called by the framework to notify the framework and remote application that the
+     * {@link SipDelegate} has been successfully created.
+     *
+     * @param delegate The SipDelegate created to service the DelegateRequest.
+     * @param deniedTags A List of {@link FeatureTagState}, which contains the feature tags
+     *    associated with this {@link SipDelegate} that have no access to send/receive SIP messages
+     *    as well as a reason for why the feature tag is denied. For more information on the reason
+     *    why the feature tag was denied access, see the
+     *    {@link SipDelegateManager.DeniedReason} reasons. This is considered a permanent denial due
+     *    to this {@link SipDelegate} not supporting a feature or this ImsService already
+     *    implementing this feature elsewhere. If all features of this {@link SipDelegate} are
+     *    denied, {@link #onCreated(SipDelegate, List)} should still be called as the framework will
+     *    later call {@link SipTransportImplBase#destroySipDelegate(SipDelegate, int)} to clean the
+     *    delegate up.
+     */
+    void onCreated(@NonNull SipDelegate delegate, @Nullable List<FeatureTagState> deniedTags);
+
+    /**
+     * This must be called by the ImsService after the framework calls
+     * {@link SipTransportImplBase#destroySipDelegate} to notify the framework and remote
+     * application that the procedure to destroy the {@link SipDelegate} has been completed.
+     * @param reasonCode The reason for closing this delegate.
+     */
+    void onDestroyed(@SipDelegateManager.SipDelegateDestroyReason int reasonCode);
+
+    /**
+     * Call to notify the remote application of a configuration change associated with this
+     * {@link SipDelegate}.
+     * <p>
+     * The remote application will not be able to proceed sending SIP messages until after this
+     * configuration is sent the first time, so this configuration should be sent as soon as the
+     * {@link SipDelegate} has access to these configuration parameters.
+     * <p>
+     * Incoming SIP messages should not be routed to the remote application until AFTER this
+     * configuration change is sent to ensure that the remote application can respond correctly.
+     * Similarly, if there is an event that triggers the IMS configuration to change, incoming SIP
+     * messages routing should be delayed until the {@link SipDelegate} sends the IMS configuration
+     * change event to reduce conditions where the remote application is using a stale IMS
+     * configuration.
+     */
+    void onImsConfigurationChanged(@NonNull SipDelegateImsConfiguration config);
+
+    /**
+     * Call to notify the remote application that the {@link SipDelegate} has modified the IMS
+     * registration state of the RCS feature tags that were requested as part of the initial
+     * {@link DelegateRequest}.
+     * <p>
+     * See {@link DelegateRegistrationState} for more information about how IMS Registration state
+     * should be communicated the associated SipDelegateConnection in cases such as
+     * IMS deregistration, handover, PDN change, provisioning changes, etc…
+     * <p>
+     * Note: Even after the status of the feature tags are updated here to deregistered, the
+     * SipDelegate must still be able to handle these messages and call
+     * {@link DelegateMessageCallback#onMessageSendFailure} to notify the RCS application that the
+     * message was not sent.
+     *
+     * @param registrationState The current network IMS registration state for all feature tags
+     *         associated with this SipDelegate.
+     */
+    void onFeatureTagRegistrationChanged(@NonNull DelegateRegistrationState registrationState);
+}
diff --git a/telephony/java/android/telephony/ims/FeatureTagState.java b/telephony/java/android/telephony/ims/FeatureTagState.java
new file mode 100644
index 000000000000..060be6f2510d
--- /dev/null
+++ b/telephony/java/android/telephony/ims/FeatureTagState.java
@@ -0,0 +1,131 @@
+/*
+ * Copyright (C) 2020 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.telephony.ims;
+
+import android.annotation.NonNull;
+import android.os.Parcel;
+import android.os.Parcelable;
+import android.telephony.ims.stub.DelegateConnectionStateCallback;
+import android.telephony.ims.stub.SipDelegate;
+
+import java.util.List;
+import java.util.Objects;
+
+/**
+ * Maps an IMS media feature tag 3gpp universal resource name (URN) previously mapped to a
+ * {@link SipDelegate} in the associated {@link DelegateRequest} to its current availability
+ * state as set by the ImsService managing the related IMS registration.
+ *
+ * This class is only used to report more information about a IMS feature tag that is not fully
+ * available at this time.
+ * <p>
+ * Please see {@link DelegateRegistrationState}, {@link DelegateStateCallback}, and
+ * {@link DelegateConnectionStateCallback} for more information about how this class is used to
+ * convey the state of IMS feature tags that were requested by {@link DelegateRequest} but are not
+ * currently available.
+ * @hide
+ */
+public final class FeatureTagState implements Parcelable {
+
+    private final String mFeatureTag;
+    private final int mState;
+
+    /**
+     * Associate an IMS feature tag with its current state. See {@link DelegateRegistrationState}
+     * and {@link DelegateConnectionStateCallback#onFeatureTagStatusChanged(
+     * DelegateRegistrationState, List)} and
+     * {@link DelegateStateCallback#onCreated(SipDelegate, List)} for examples on how and when this
+     * is used.
+     *
+     * @param featureTag The IMS feature tag that is deregistered, in the process of
+     *                   deregistering, or denied.
+     * @param state The {@link DelegateRegistrationState.DeregisteredReason},
+     *         {@link DelegateRegistrationState.DeregisteringReason}, or
+     *         {@link SipDelegateManager.DeniedReason} associated with this feature tag.
+     */
+    public FeatureTagState(@NonNull String featureTag, int state) {
+        mFeatureTag = featureTag;
+        mState = state;
+    }
+
+    /**
+     * Used for constructing instances during un-parcelling.
+     */
+    private FeatureTagState(Parcel source) {
+        mFeatureTag = source.readString();
+        mState = source.readInt();
+    }
+
+    /**
+     * @return The IMS feature tag string that is in the process of deregistering,
+     * deregistered, or denied.
+     */
+    public @NonNull String getFeatureTag() {
+        return mFeatureTag;
+    }
+
+    /**
+     * @return The reason for why the feature tag is currently in the process of deregistering,
+     * has been deregistered, or has been denied. See {@link DelegateRegistrationState} and
+     * {@link DelegateConnectionStateCallback} for more information.
+     */
+    public int getState() {
+        return mState;
+    }
+
+    @Override
+    public int describeContents() {
+        return 0;
+    }
+
+    @Override
+    public void writeToParcel(Parcel dest, int flags) {
+        dest.writeString(mFeatureTag);
+        dest.writeInt(mState);
+    }
+
+    public static final Creator<FeatureTagState> CREATOR = new Creator<FeatureTagState>() {
+        @Override
+        public FeatureTagState createFromParcel(Parcel source) {
+            return new FeatureTagState(source);
+        }
+
+        @Override
+        public FeatureTagState[] newArray(int size) {
+            return new FeatureTagState[size];
+        }
+    };
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+        FeatureTagState that = (FeatureTagState) o;
+        return mState == that.mState
+                && mFeatureTag.equals(that.mFeatureTag);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(mFeatureTag, mState);
+    }
+
+    @Override
+    public String toString() {
+        return "FeatureTagState{" + "mFeatureTag='" + mFeatureTag + ", mState=" + mState + '}';
+    }
+}
diff --git a/telephony/java/android/telephony/ims/SipDelegateConnection.java b/telephony/java/android/telephony/ims/SipDelegateConnection.java
new file mode 100644
index 000000000000..6bfdc2c6d48a
--- /dev/null
+++ b/telephony/java/android/telephony/ims/SipDelegateConnection.java
@@ -0,0 +1,73 @@
+/*
+ * Copyright (C) 2020 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.telephony.ims;
+
+import android.annotation.NonNull;
+import android.telephony.ims.stub.SipDelegate;
+
+/**
+ * Represents a connection to the remote {@link SipDelegate} that is managed by the
+ * {@link ImsService} implementing IMS for the subscription that is associated with it.
+ * <p>
+ * The remote delegate will handle messages sent by this {@link SipDelegateConnection}, notifying
+ * the associated {@link DelegateMessageCallback} when the message was either sent successfully or
+ * failed to be sent.
+ * <p>
+ * It is also the responsibility of this {@link SipDelegateConnection} to acknowledge when incoming
+ * SIP messages have been received successfully via
+ * {@link DelegateMessageCallback#onMessageReceived(SipMessage)} or when there was an error
+ * receiving the message using {@link #notifyMessageReceived(String)} and
+ * {@link #notifyMessageReceiveError(String, int)}.
+ *
+ * @see SipDelegateManager#createSipDelegate
+ * @hide
+ */
+public interface SipDelegateConnection {
+
+    /**
+     * Send a SIP message to the SIP delegate to be sent over the carrier’s network. The
+     * {@link SipMessage} will either be acknowledged with
+     * {@link DelegateMessageCallback#onMessageSent(String)} upon successful sending of this message
+     * or {@link DelegateMessageCallback#onMessageSendFailure(String, int)} if there was an error
+     * sending the message.
+     * @param sipMessage The SipMessage to be sent.
+     * @param configVersion The SipDelegateImsConfiguration version used to construct the
+     *                      SipMessage. See {@link SipDelegateImsConfiguration#getVersion} for more
+     *                      information on this parameter and why it is used.
+     */
+    void sendMessage(@NonNull SipMessage sipMessage, int configVersion);
+
+    /**
+     * Notify the {@link SipDelegate} that a SIP message received from
+     * {@link DelegateMessageCallback#onMessageReceived(SipMessage)} has been received successfully
+     * and is being processed.
+     * @param viaTransactionId Per RFC3261 Sec 8.1.1.7 the transaction ID associated with the Via
+     *         branch parameter.
+     */
+    void notifyMessageReceived(@NonNull String viaTransactionId);
+
+    /**
+     * Notify the SIP delegate that the SIP message has been received from
+     * {@link DelegateMessageCallback#onMessageReceived(SipMessage)}, however there was an error
+     * processing it.
+     * @param viaTransactionId Per RFC3261 Sec 8.1.1.7 the transaction ID associated with the Via
+     *         branch parameter.
+     * @param reason The reason why the error occurred.
+     */
+    void notifyMessageReceiveError(@NonNull String viaTransactionId,
+            @SipDelegateManager.MessageFailureReason int reason);
+}
diff --git a/telephony/java/android/telephony/ims/SipDelegateImsConfiguration.java b/telephony/java/android/telephony/ims/SipDelegateImsConfiguration.java
new file mode 100644
index 000000000000..8abd0ee94865
--- /dev/null
+++ b/telephony/java/android/telephony/ims/SipDelegateImsConfiguration.java
@@ -0,0 +1,499 @@
+/*
+ * Copyright (C) 2020 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.telephony.ims;
+
+import android.annotation.NonNull;
+import android.annotation.StringDef;
+import android.os.Parcel;
+import android.os.Parcelable;
+import android.os.PersistableBundle;
+import android.telephony.ims.stub.SipDelegate;
+
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+
+/**
+ * The IMS registration and other attributes that the {@link SipDelegateConnection} used by the
+ * IMS application will need to be aware of to correctly generate outgoing {@link SipMessage}s.
+ * <p>
+ * The IMS service must generate new instances of this configuration as the IMS configuration
+ * managed by the IMS service changes. Along with each {@link SipDelegateImsConfiguration} instance
+ * containing the configuration is the "version", which should be incremented every time a new
+ * {@link SipDelegateImsConfiguration} instance is created. The {@link SipDelegateConnection} will
+ * include the version of the {@link SipDelegateImsConfiguration} instance that it used in order for
+ * the {@link SipDelegate} to easily identify if the IMS application used a now stale configuration
+ * to generate the {@link SipMessage} and return
+ * {@link SipDelegateManager#MESSAGE_FAILURE_REASON_STALE_IMS_CONFIGURATION} in
+ * {@link DelegateMessageCallback#onMessageSendFailure(String, int)} so that the IMS application can
+ * regenerate that {@link SipMessage} using the correct {@link SipDelegateImsConfiguration}
+ * instance.
+ * <p>
+ * Every time the IMS configuration state changes in the IMS service, a full configuration should
+ * be generated. The new  {@link SipDelegateImsConfiguration} instance should not be an incremental
+ * update.
+ * @hide
+ */
+public class SipDelegateImsConfiguration implements Parcelable {
+
+    /**
+     * IPV4 Address type.
+     * <p>
+     * Used as a potential value for {@link #KEY_SIP_CONFIG_IPTYPE_STRING}.
+     */
+    public static final String IPTYPE_IPV4 = "IPV4";
+
+    /**
+     * IPV6 Address type.
+     * <p>
+     * Used as a potential value for {@link #KEY_SIP_CONFIG_IPTYPE_STRING}.
+     */
+    public static final String IPTYPE_IPV6 = "IPV6";
+
+    /**
+     * The SIP transport uses UDP.
+     * <p>
+     * Used as a potential value for {@link #KEY_SIP_CONFIG_TRANSPORT_TYPE_STRING}.
+     */
+    public static final String SIP_TRANSPORT_UDP = "UDP";
+
+    /**
+     * The SIP transport uses TCP.
+     * <p>
+     * Used as a potential value for {@link #KEY_SIP_CONFIG_TRANSPORT_TYPE_STRING}.
+     */
+    public static final String SIP_TRANSPORT_TCP = "TCP";
+
+    /**
+     * Flag specifying if SIP compact form is enabled
+     */
+    public static final String KEY_SIP_CONFIG_IS_COMPACT_FORM_ENABLED_BOOL =
+            "sip_config_is_compact_form_enabled_bool";
+
+    /**
+     * Flag specifying if SIP keepalives are enabled
+     */
+    public static final String KEY_SIP_CONFIG_IS_KEEPALIVE_ENABLED_BOOL =
+            "sip_config_is_keepalive_enabled_bool";
+
+    /**
+     * Maximum SIP payload to be sent on UDP. If the SIP message payload is greater than max udp
+     * payload size, then TCP must be used
+     */
+    public static final String KEY_SIP_CONFIG_MAX_PAYLOAD_SIZE_ON_UDP_INT =
+            "sip_config_udp_max_payload_size_int";
+
+    /**
+     * Transport protocol used for SIP signaling.
+     * Available options are: {@link #SIP_TRANSPORT_UDP }, {@link #SIP_TRANSPORT_TCP }
+     */
+    public static final String KEY_SIP_CONFIG_TRANSPORT_TYPE_STRING =
+            "sip_config_protocol_type_string";
+
+    /**
+     * IMS public user identifier string
+     */
+    public static final String KEY_SIP_CONFIG_UE_PUBLIC_USER_ID_STRING =
+            "sip_config_ue_public_user_id_string";
+
+    /**
+     * IMS private user identifier string
+     */
+    public static final String KEY_SIP_CONFIG_UE_PRIVATE_USER_ID_STRING =
+            "sip_config_ue_private_user_id_string";
+
+    /**
+     * IMS home domain string
+     */
+    public static final String KEY_SIP_CONFIG_HOME_DOMAIN_STRING = "sip_config_home_domain_string";
+
+    /**
+     * IMEI string. Application can include the Instance-ID feature tag " +sip.instance" in the
+     * Contact header with a value of the device IMEI in the form "urn:gsma:imei:<device IMEI>".
+     */
+    public static final String KEY_SIP_CONFIG_IMEI_STRING = "sip_config_imei_string";
+
+    /**
+     * IP address type for SIP signaling.
+     * Available options are: {@link #IPTYPE_IPV6}, {@link #IPTYPE_IPV4}
+     */
+    public static final String KEY_SIP_CONFIG_IPTYPE_STRING = "sip_config_iptype_string";
+
+    /**
+     * Local IPaddress used for SIP signaling.
+     */
+    public static final String KEY_SIP_CONFIG_UE_DEFAULT_IPADDRESS_STRING =
+            "sip_config_ue_default_ipaddress_string";
+
+    /**
+     * Local port used for sending SIP traffic
+     */
+    public static final String KEY_SIP_CONFIG_UE_DEFAULT_PORT_INT =
+            "sip_config_ue_default_port_int";
+
+    /**
+     * SIP server / PCSCF default ip address
+     */
+    public static final String KEY_SIP_CONFIG_SERVER_DEFAULT_IPADDRESS_STRING =
+            "sip_config_server_default_ipaddress_string";
+
+    /**
+     * SIP server / PCSCF port used for sending SIP traffic
+     */
+    public static final String KEY_SIP_CONFIG_SERVER_DEFAULT_PORT_INT =
+            "sip_config_server_default_port_int";
+
+    /**
+     * Flag specifying if Network Address Translation is enabled and UE is behind a NAT.
+     */
+    public static final String KEY_SIP_CONFIG_IS_NAT_ENABLED_BOOL =
+            "sip_config_is_nat_enabled_bool";
+
+    /**
+     * UE's public IPaddress when UE is behind a NAT.
+     * <p>
+     * This key will not exist if {@link #KEY_SIP_CONFIG_IS_NAT_ENABLED_BOOL} is {@code false}.
+     */
+    public static final String KEY_SIP_CONFIG_UE_PUBLIC_IPADDRESS_WITH_NAT_STRING =
+            "sip_config_ue_public_ipaddress_with_nat_string";
+
+    /**
+     * UE's public SIP port when UE is behind a NAT.
+     * <p>
+     * This key will not exist if {@link #KEY_SIP_CONFIG_IS_NAT_ENABLED_BOOL} is {@code false}.
+     */
+    public static final String KEY_SIP_CONFIG_UE_PUBLIC_PORT_WITH_NAT_INT =
+            "sip_config_ue_public_port_with_nat_int";
+
+    /**
+     * Flag specifying if Globally routable user-agent uri (GRUU) is enabled as per TS 23.808
+     */
+    public static final String KEY_SIP_CONFIG_IS_GRUU_ENABLED_BOOL =
+            "sip_config_is_gruu_enabled_bool";
+
+    /**
+     * UE's Globally routable user-agent uri if this feature is enabled.
+     * <p>
+     * This key will not exist if {@link #KEY_SIP_CONFIG_IS_GRUU_ENABLED_BOOL} is {@code false}.
+     */
+    public static final String KEY_SIP_CONFIG_UE_PUBLIC_GRUU_STRING =
+            "sip_config_ue_public_gruu_string";
+
+    /**
+     * Flag specifying if SIP over IPSec is enabled.
+     */
+    public static final String KEY_SIP_CONFIG_IS_IPSEC_ENABLED_BOOL =
+            "sip_config_is_ipsec_enabled_bool";
+    /**
+     * UE's SIP port used to send traffic when IPSec is enabled.
+     * <p>
+     * This key will not exist if {@link #KEY_SIP_CONFIG_IS_IPSEC_ENABLED_BOOL} is {@code false}.
+     */
+    public static final String KEY_SIP_CONFIG_UE_IPSEC_CLIENT_PORT_INT =
+            "sip_config_ue_ipsec_client_port_int";
+
+    /**
+     * UE's SIP port used to receive traffic when IPSec is enabled.
+     * <p>
+     * This key will not exist if {@link #KEY_SIP_CONFIG_IS_IPSEC_ENABLED_BOOL} is {@code false}.
+     */
+    public static final String KEY_SIP_CONFIG_UE_IPSEC_SERVER_PORT_INT =
+            "sip_config_ue_ipsec_server_port_int";
+
+    /**
+     * UE's SIP port used for the previous IPsec security association if IPSec is enabled.
+     * <p>
+     * This key will not exist if {@link #KEY_SIP_CONFIG_IS_IPSEC_ENABLED_BOOL} is {@code false}.
+     */
+    public static final String KEY_SIP_CONFIG_UE_IPSEC_OLD_CLIENT_PORT_INT =
+            "sip_config_ue_ipsec_old_client_port_int";
+
+    /**
+     * Port number used by the SIP server to send SIP traffic when IPSec is enabled.
+     * <p>
+     * This key will not exist if {@link #KEY_SIP_CONFIG_IS_IPSEC_ENABLED_BOOL} is {@code false}.
+     */
+    public static final String KEY_SIP_CONFIG_SERVER_IPSEC_CLIENT_PORT_INT =
+            "sip_config_server_ipsec_client_port_int";
+
+    /**
+     * Port number used by the SIP server to receive incoming SIP traffic when IPSec is enabled.
+     * <p>
+     * This key will not exist if {@link #KEY_SIP_CONFIG_IS_IPSEC_ENABLED_BOOL} is {@code false}.
+     */
+    public static final String KEY_SIP_CONFIG_SERVER_IPSEC_SERVER_PORT_INT =
+            "sip_config_server_ipsec_server_port_int";
+
+    /**
+     * Port number used by the SIP server to send SIP traffic on the previous IPSec security
+     * association when IPSec is enabled.
+     * <p>
+     * This key will not exist if {@link #KEY_SIP_CONFIG_IS_IPSEC_ENABLED_BOOL} is {@code false}.
+     */
+    public static final String KEY_SIP_CONFIG_SERVER_IPSEC_OLD_CLIENT_PORT_INT =
+            "sip_config_server_ipsec_old_client_port_int";
+    /**
+     * SIP Authentication header string
+     */
+    public static final String KEY_SIP_CONFIG_AUTHENTICATION_HEADER_STRING =
+            "sip_config_auhentication_header_string";
+
+    /**
+     * SIP Authentication nonce string
+     */
+    public static final String KEY_SIP_CONFIG_AUTHENTICATION_NONCE_STRING =
+            "sip_config_authentication_nonce_string";
+
+    /**
+     * SIP service route header string
+     */
+    public static final String KEY_SIP_CONFIG_SERVICE_ROUTE_HEADER_STRING =
+            "sip_config_service_route_header_string";
+
+    /**
+     * SIP security verify header string
+     */
+    public static final String KEY_SIP_CONFIG_SECURITY_VERIFY_HEADER_STRING =
+            "sip_config_security_verify_header_string";
+
+    /**
+     * SIP Path header string
+     */
+    public static final String KEY_SIP_CONFIG_PATH_HEADER_STRING =
+            "sip_config_path_header_string";
+
+    /**
+     * SIP User part string in contact header
+     */
+    public static final String KEY_SIP_CONFIG_URI_USER_PART_STRING =
+            "sip_config_uri_user_part_string";
+
+    /**
+     * SIP P-access-network-info header string
+     */
+    public static final String KEY_SIP_CONFIG_P_ACCESS_NETWORK_INFO_HEADER_STRING =
+            "sip_config_p_access_network_info_header_string";
+
+    /**
+     * SIP P-last-access-network-info header string
+     */
+    public static final String KEY_SIP_CONFIG_P_LAST_ACCESS_NETWORK_INFO_HEADER_STRING =
+            "sip_config_p_last_access_network_info_header_string";
+
+    /**
+     * SIP P-associated-uri header string
+     */
+    public static final String KEY_SIP_CONFIG_P_ASSOCIATED_URI_HEADER_STRING =
+            "sip_config_p_associated_uri_header_string";
+
+    /**@hide*/
+    @StringDef(prefix = "KEY_SIP_CONFIG", suffix = "_STRING", value = {
+            KEY_SIP_CONFIG_TRANSPORT_TYPE_STRING,
+            KEY_SIP_CONFIG_UE_PUBLIC_USER_ID_STRING,
+            KEY_SIP_CONFIG_UE_PRIVATE_USER_ID_STRING,
+            KEY_SIP_CONFIG_HOME_DOMAIN_STRING,
+            KEY_SIP_CONFIG_IMEI_STRING,
+            KEY_SIP_CONFIG_IPTYPE_STRING,
+            KEY_SIP_CONFIG_UE_DEFAULT_IPADDRESS_STRING,
+            KEY_SIP_CONFIG_SERVER_DEFAULT_IPADDRESS_STRING,
+            KEY_SIP_CONFIG_UE_PUBLIC_IPADDRESS_WITH_NAT_STRING,
+            KEY_SIP_CONFIG_UE_PUBLIC_GRUU_STRING,
+            KEY_SIP_CONFIG_AUTHENTICATION_HEADER_STRING,
+            KEY_SIP_CONFIG_AUTHENTICATION_NONCE_STRING,
+            KEY_SIP_CONFIG_SERVICE_ROUTE_HEADER_STRING,
+            KEY_SIP_CONFIG_SECURITY_VERIFY_HEADER_STRING,
+            KEY_SIP_CONFIG_PATH_HEADER_STRING,
+            KEY_SIP_CONFIG_URI_USER_PART_STRING,
+            KEY_SIP_CONFIG_P_ACCESS_NETWORK_INFO_HEADER_STRING,
+            KEY_SIP_CONFIG_P_LAST_ACCESS_NETWORK_INFO_HEADER_STRING,
+            KEY_SIP_CONFIG_P_ASSOCIATED_URI_HEADER_STRING
+    })
+    @Retention(RetentionPolicy.SOURCE)
+    public @interface StringConfigKey {}
+
+    /**@hide*/
+    @StringDef(prefix = "KEY_SIP_CONFIG", suffix = "_INT", value = {
+            KEY_SIP_CONFIG_MAX_PAYLOAD_SIZE_ON_UDP_INT,
+            KEY_SIP_CONFIG_UE_DEFAULT_PORT_INT,
+            KEY_SIP_CONFIG_SERVER_DEFAULT_PORT_INT,
+            KEY_SIP_CONFIG_UE_PUBLIC_PORT_WITH_NAT_INT,
+            KEY_SIP_CONFIG_UE_IPSEC_CLIENT_PORT_INT,
+            KEY_SIP_CONFIG_UE_IPSEC_SERVER_PORT_INT,
+            KEY_SIP_CONFIG_UE_IPSEC_OLD_CLIENT_PORT_INT,
+            KEY_SIP_CONFIG_SERVER_IPSEC_CLIENT_PORT_INT,
+            KEY_SIP_CONFIG_SERVER_IPSEC_SERVER_PORT_INT,
+            KEY_SIP_CONFIG_SERVER_IPSEC_OLD_CLIENT_PORT_INT
+    })
+    @Retention(RetentionPolicy.SOURCE)
+    public @interface IntConfigKey {}
+
+    /**@hide*/
+    @StringDef(prefix = "KEY_SIP_CONFIG", suffix = "_BOOL", value = {
+            KEY_SIP_CONFIG_IS_COMPACT_FORM_ENABLED_BOOL,
+            KEY_SIP_CONFIG_IS_KEEPALIVE_ENABLED_BOOL,
+            KEY_SIP_CONFIG_IS_NAT_ENABLED_BOOL,
+            KEY_SIP_CONFIG_IS_GRUU_ENABLED_BOOL,
+            KEY_SIP_CONFIG_IS_IPSEC_ENABLED_BOOL
+    })
+    @Retention(RetentionPolicy.SOURCE)
+    public @interface BooleanConfigKey {}
+
+    /**
+     * Builder class to be used when constructing a new SipDelegateImsConfiguration.
+     */
+    public static class Builder {
+        private final long mVersion;
+        private final PersistableBundle mBundle;
+
+        /**
+         * Creates an empty implementation of SipDelegateImsConfiguration.
+         * @param version The version associated with the SipDelegateImsConfiguration being built.
+         *                See {@link #getVersion} for more information.
+         */
+        public Builder(int version) {
+            mVersion = version;
+            mBundle = new PersistableBundle();
+        }
+        /**
+         * Clones an existing implementation of SipDelegateImsConfiguration to handle situations
+         * where only a small number of parameters have changed from the previous configuration.
+         * <p>
+         * Automatically increments the version of this configuration by 1. See {@link #getVersion}
+         * for more information.
+         */
+        public Builder(@NonNull SipDelegateImsConfiguration config) {
+            mVersion = config.getVersion() + 1;
+            mBundle = config.copyBundle();
+        }
+        /**
+         * Put a string value into this configuration bundle for the given key.
+         */
+        public Builder putString(@StringConfigKey String key, String value) {
+            mBundle.putString(key, value);
+            return this;
+        }
+
+        /**
+         * Replace the existing default value with a new value for a given key.
+         */
+        public Builder putInt(@IntConfigKey String key, int value) {
+            mBundle.putInt(key, value);
+            return this;
+        }
+
+        /**
+         * Replace the existing default value with a new value for a given key.
+         */
+        public Builder putBoolean(@BooleanConfigKey String key, boolean value) {
+            mBundle.putBoolean(key, value);
+            return this;
+        }
+
+        /**
+         * @return a new SipDelegateImsConfiguration from this Builder.
+         */
+        public SipDelegateImsConfiguration build() {
+            return new SipDelegateImsConfiguration(mVersion, mBundle);
+        }
+    }
+
+    private final long mVersion;
+    private final PersistableBundle mBundle;
+
+    private SipDelegateImsConfiguration(long version, PersistableBundle bundle) {
+        mVersion = version;
+        mBundle = bundle;
+    }
+
+    private SipDelegateImsConfiguration(Parcel source) {
+        mVersion = source.readLong();
+        mBundle = source.readPersistableBundle();
+    }
+
+    /**
+     * @return the string value associated with a given key or {@code null} if it doesn't exist.
+     */
+    public @StringConfigKey String getString(String key) {
+        return mBundle.getString(key);
+    }
+
+    /**
+     * @return the Integer value associated with a given key or {@code null} if the value doesn't
+     * exist.
+     */
+    public @IntConfigKey Integer getInt(String key) {
+        if (!mBundle.containsKey(key)) {
+            return null;
+        }
+        return mBundle.getInt(key);
+    }
+
+    /**
+     * @return the Integer value associated with a given key or {@code null} if the value doesn't
+     * exist.
+     */
+    public @BooleanConfigKey Boolean getBoolen(String key) {
+        if (!mBundle.containsKey(key)) {
+            return null;
+        }
+        return mBundle.getBoolean(key);
+    }
+
+    /**
+     * @return a shallow copy of the full configuration.
+     */
+    public PersistableBundle copyBundle() {
+        return new PersistableBundle(mBundle);
+    }
+
+    /**
+     * An integer representing the version number of this SipDelegateImsConfiguration.
+     * {@link SipMessage}s that are created using this configuration will also have a this
+     * version number associated with them, which will allow the IMS service to validate that the
+     * {@link SipMessage} was using the latest configuration during creation and not a stale
+     * configuration due to race conditions between the configuration being updated and the RCS
+     * application not receiving the updated configuration before generating a new message.
+     *
+     * @return the version number associated with this {@link SipDelegateImsConfiguration}.
+     */
+    public long getVersion() {
+        return mVersion;
+    }
+
+    @Override
+    public int describeContents() {
+        return 0;
+    }
+
+    @Override
+    public void writeToParcel(Parcel dest, int flags) {
+        dest.writeLong(mVersion);
+        dest.writePersistableBundle(mBundle);
+    }
+
+    public static final Creator<SipDelegateImsConfiguration> CREATOR =
+            new Creator<SipDelegateImsConfiguration>() {
+        @Override
+        public SipDelegateImsConfiguration createFromParcel(Parcel source) {
+            return new SipDelegateImsConfiguration(source);
+        }
+
+        @Override
+        public SipDelegateImsConfiguration[] newArray(int size) {
+            return new SipDelegateImsConfiguration[size];
+        }
+    };
+}
diff --git a/telephony/java/android/telephony/ims/SipDelegateManager.java b/telephony/java/android/telephony/ims/SipDelegateManager.java
index 82c8a9cd58f4..3c59d4f6209c 100644
--- a/telephony/java/android/telephony/ims/SipDelegateManager.java
+++ b/telephony/java/android/telephony/ims/SipDelegateManager.java
@@ -17,6 +17,8 @@
 package android.telephony.ims;
 
 import android.Manifest;
+import android.annotation.IntDef;
+import android.annotation.NonNull;
 import android.annotation.RequiresPermission;
 import android.annotation.SystemApi;
 import android.content.Context;
@@ -26,18 +28,237 @@ import android.os.ServiceSpecificException;
 import android.telephony.CarrierConfigManager;
 import android.telephony.TelephonyFrameworkInitializer;
 import android.telephony.ims.aidl.IImsRcsController;
+import android.telephony.ims.stub.DelegateConnectionMessageCallback;
+import android.telephony.ims.stub.DelegateConnectionStateCallback;
+import android.telephony.ims.stub.SipDelegate;
 
 import com.android.internal.annotations.VisibleForTesting;
 
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.util.concurrent.Executor;
+
 /**
- * Manages the creation and destruction of SipDelegates, which allow an IMS application to forward
- * SIP messages for the purposes of providing a single IMS registration to the carrier's IMS network
- * from multiple sources.
+ * Manages the creation and destruction of SipDelegates for the {@link ImsService} managing IMS
+ * for the subscription ID that this SipDelegateManager has been created for.
+ *
+ * This allows multiple IMS applications to forward SIP messages to/from their application for the
+ * purposes of providing a single IMS registration to the carrier's IMS network from potentially
+ * many IMS stacks implementing a subset of the supported MMTEL/RCS features.
  * @hide
  */
 @SystemApi
 public class SipDelegateManager {
 
+    /**
+     * The SIP message has failed being sent or received for an unknown reason.
+     * <p>
+     * The caller should retry a message that failed with this response.
+     * @hide
+     */
+    public static final int MESSAGE_FAILURE_REASON_UNKNOWN = 0;
+
+    /**
+     * The remote service associated with this connection has died and the message was not
+     * properly sent/received.
+     * <p>
+     * This is considered a permanent error and the system will automatically begin the teardown and
+     * destruction of the SipDelegate. No further messages should be sent on this transport.
+     * @hide
+     */
+    public static final int MESSAGE_FAILURE_REASON_DELEGATE_DEAD = 1;
+
+    /**
+     * The message has not been sent/received because the delegate is in the process of closing and
+     * has become unavailable. No further messages should be sent/received on this delegate.
+     * @hide
+     */
+    public static final int MESSAGE_FAILURE_REASON_DELEGATE_CLOSED = 2;
+
+    /**
+     * The SIP message has an invalid start line and the message can not be sent.
+     * @hide
+     */
+    public static final int MESSAGE_FAILURE_REASON_INVALID_START_LINE = 3;
+
+    /**
+     * One or more of the header fields in the header section of the outgoing SIP message is invalid
+     * and the SIP message can not be sent.
+     * @hide
+     */
+    public static final int MESSAGE_FAILURE_REASON_INVALID_HEADER_FIELDS = 4;
+
+    /**
+     * The body content of the SIP message is invalid and the message can not be sent.
+     * @hide
+     */
+    public static final int MESSAGE_FAILURE_REASON_INVALID_BODY_CONTENT = 5;
+
+    /**
+     * The feature tag associated with the outgoing message does not match any known feature tags
+     * and this message can not be sent.
+     * @hide
+     */
+    public static final int MESSAGE_FAILURE_REASON_INVALID_FEATURE_TAG = 6;
+
+    /**
+     * The feature tag associated with the outgoing message is not enabled for the associated
+     * SipDelegateConnection and can not be sent.
+     * @hide
+     */
+    public static final int MESSAGE_FAILURE_REASON_TAG_NOT_ENABLED_FOR_DELEGATE = 7;
+
+    /**
+     * The link to the network has been lost and the outgoing message has failed to send.
+     * <p>
+     * This message should be retried when connectivity to the network is re-established. See
+     * {@link android.net.ConnectivityManager.NetworkCallback} for how this can be determined.
+     * @hide
+     */
+    public static final int MESSAGE_FAILURE_REASON_NETWORK_NOT_AVAILABLE = 8;
+
+    /**
+     * The outgoing SIP message has not been sent due to the SipDelegate not being registered for
+     * IMS at this time.
+     * <p>
+     * This is considered a temporary failure, the message should not be retried until an IMS
+     * registration change callback is received via
+     * {@link DelegateConnectionStateCallback#onFeatureTagStatusChanged}
+     * @hide
+     */
+    public static final int MESSAGE_FAILURE_REASON_NOT_REGISTERED = 9;
+
+    /**
+     * The outgoing SIP message has not been sent because the {@link SipDelegateImsConfiguration}
+     * version associated with the outgoing {@link SipMessage} is now stale and has failed
+     * validation checks.
+     * <p>
+     * The @link SipMessage} should be recreated using the newest
+     * {@link SipDelegateImsConfiguration} and sent again.
+     * @hide
+     */
+    public static final int MESSAGE_FAILURE_REASON_STALE_IMS_CONFIGURATION = 10;
+
+    /**
+     * The outgoing SIP message has not been sent because the internal state of the associated
+     * {@link SipDelegate} is changing and has temporarily brought the transport down.
+     * <p>
+     * This is considered a temporary error and the {@link SipDelegateConnection} should resend the
+     * message once {@link DelegateRegistrationState#DEREGISTERING_REASON_FEATURE_TAGS_CHANGING} is
+     * no longer reported.
+     * @hide
+     */
+    public static final int MESSAGE_FAILURE_REASON_INTERNAL_DELEGATE_STATE_TRANSITION = 11;
+
+    /** @hide */
+    @Retention(RetentionPolicy.SOURCE)
+    @IntDef(prefix = "MESSAGE_FAILURE_REASON_", value = {
+            MESSAGE_FAILURE_REASON_UNKNOWN,
+            MESSAGE_FAILURE_REASON_DELEGATE_DEAD,
+            MESSAGE_FAILURE_REASON_DELEGATE_CLOSED,
+            MESSAGE_FAILURE_REASON_INVALID_START_LINE,
+            MESSAGE_FAILURE_REASON_INVALID_HEADER_FIELDS,
+            MESSAGE_FAILURE_REASON_INVALID_BODY_CONTENT,
+            MESSAGE_FAILURE_REASON_INVALID_FEATURE_TAG,
+            MESSAGE_FAILURE_REASON_TAG_NOT_ENABLED_FOR_DELEGATE,
+            MESSAGE_FAILURE_REASON_NETWORK_NOT_AVAILABLE,
+            MESSAGE_FAILURE_REASON_NOT_REGISTERED,
+            MESSAGE_FAILURE_REASON_STALE_IMS_CONFIGURATION,
+            MESSAGE_FAILURE_REASON_INTERNAL_DELEGATE_STATE_TRANSITION
+    })
+    public @interface MessageFailureReason {}
+
+
+    /**
+     * Access to use this feature tag has been denied for an unknown reason.
+     * @hide
+     */
+    public static final int DENIED_REASON_UNKNOWN = 0;
+
+    /**
+     * This feature tag is allowed to be used by this SipDelegateConnection, but it is in use by
+     * another SipDelegateConnection and can not be associated with this delegate. The feature tag
+     * will stay in this state until the feature tag is release by the other application.
+     * @hide
+     */
+    public static final int DENIED_REASON_IN_USE_BY_ANOTHER_DELEGATE = 1;
+
+    /**
+     * Access to use this feature tag has been denied because this application does not have the
+     * permissions required to access this feature tag.
+     * @hide
+     */
+    public static final int DENIED_REASON_NOT_ALLOWED = 2;
+
+    /**
+     * Access to use this feature tag has been denied because single registration is not allowed by
+     * the carrier at this time. The application should fall back to dual registration if
+     * applicable.
+     * @hide
+     */
+    public static final int DENIED_REASON_SINGLE_REGISTRATION_NOT_ALLOWED = 3;
+
+    /**
+     * This feature tag is not recognized as a valid feature tag by the SipDelegate and has been
+     * denied.
+     * @hide
+     */
+    public static final int DENIED_REASON_INVALID = 4;
+
+    /** @hide */
+    @Retention(RetentionPolicy.SOURCE)
+    @IntDef(prefix = "DENIED_REASON_", value = {
+            DENIED_REASON_UNKNOWN,
+            DENIED_REASON_IN_USE_BY_ANOTHER_DELEGATE,
+            DENIED_REASON_NOT_ALLOWED,
+            DENIED_REASON_SINGLE_REGISTRATION_NOT_ALLOWED,
+            DENIED_REASON_INVALID
+    })
+    public @interface DeniedReason {}
+
+    /**
+     * The SipDelegate has closed due to an unknown reason.
+     * @hide
+     */
+    public static final int SIP_DELEGATE_DESTROY_REASON_UNKNOWN = 0;
+
+    /**
+     * The SipDelegate has closed because the IMS service has died unexpectedly.
+     * @hide
+     */
+    public static final int SIP_DELEGATE_DESTROY_REASON_SERVICE_DEAD = 1;
+
+    /**
+     * The SipDelegate has closed because the IMS application has requested that the connection be
+     * destroyed.
+     * @hide
+     */
+    public static final int SIP_DELEGATE_DESTROY_REASON_REQUESTED_BY_APP = 2;
+
+    /**
+     * The SipDelegate has closed because the IMS service does not support the creation of
+     * SipDelegates.
+     * @hide
+     */
+    public static final int SIP_DELEGATE_DESTROY_REASON_SERVICE_NOT_SUPPORTED = 3;
+
+    /**
+     * The SipDelegate has been closed due to the user disabling RCS.
+     * @hide
+     */
+    public static final int SIP_DELEGATE_DESTROY_REASON_USER_DISABLED_RCS = 4;
+
+    /** @hide */
+    @Retention(RetentionPolicy.SOURCE)
+    @IntDef(prefix = "SIP_DELEGATE_DESTROY_REASON", value = {
+            SIP_DELEGATE_DESTROY_REASON_UNKNOWN,
+            SIP_DELEGATE_DESTROY_REASON_SERVICE_DEAD,
+            SIP_DELEGATE_DESTROY_REASON_REQUESTED_BY_APP,
+            SIP_DELEGATE_DESTROY_REASON_SERVICE_NOT_SUPPORTED,
+            SIP_DELEGATE_DESTROY_REASON_USER_DISABLED_RCS
+    })
+    public @interface SipDelegateDestroyReason {}
+
     private final Context mContext;
     private final int mSubId;
 
@@ -83,6 +304,57 @@ public class SipDelegateManager {
         }
     }
 
+    /**
+     * Request that the ImsService implementation create a SipDelegate, which will configure the
+     * ImsService to forward SIP traffic that matches the filtering criteria set in supplied
+     * {@link DelegateRequest} to the application that the supplied callbacks are registered for.
+     * <p>
+     * This API requires that the caller is running as part of a long-running process and will
+     * always be available to handle incoming messages. One mechanism that can be used for this is
+     * the {@link android.service.carrier.CarrierMessagingClientService}, which the framework keeps
+     * a persistent binding to when the app is the default SMS application.
+     * @param request The parameters that are associated with the SipDelegate creation request that
+     *                will be used to create the SipDelegate connection.
+     * @param e The executor that will be used to call the callbacks associated with this
+     *          SipDelegate.
+     * @param dc The callback that will be used to notify the listener of the creation/destruction
+     *           of the remote SipDelegate as well as changes to the state of the remote SipDelegate
+     *           connection.
+     * @param mc The callback that will be used to notify the listener of new incoming SIP messages
+     *           as well as the status of messages that were sent by the associated
+     *           SipDelegateConnection.
+     * @throws ImsException Thrown if there was a problem communicating with the ImsService
+     * associated with this SipDelegateManager. See {@link ImsException#getCode()}.
+     * @hide
+     */
+    public void createSipDelegate(@NonNull DelegateRequest request, @NonNull Executor e,
+            @NonNull DelegateConnectionStateCallback dc,
+            @NonNull DelegateConnectionMessageCallback mc) throws ImsException {
+        if (request == null || e == null || dc == null || mc == null) {
+            throw new IllegalArgumentException("Invalid arguments passed into createSipDelegate");
+        }
+        throw new ImsException("creating a SipDelegate is not supported" ,
+                ImsException.CODE_ERROR_UNSUPPORTED_OPERATION);
+    }
+
+    /**
+     * Destroy a previously created SipDelegateConnection that was created using
+     * {@link #createSipDelegate}.
+     * <p>
+     * This will also clean up all related callbacks in the associated ImsService.
+     * @param delegateConnection The SipDelegateConnection to destroy.
+     * @param reason The reason for why this SipDelegateConnection was destroyed.
+     * @hide
+     */
+    public void destroySipDelegate(@NonNull SipDelegateConnection delegateConnection,
+            @SipDelegateDestroyReason int reason) {
+
+        if (delegateConnection == null) {
+            throw new IllegalArgumentException("invalid argument passed into destroySipDelegate");
+        }
+        // not supported yet.
+    }
+
     private IImsRcsController getIImsRcsController() {
         IBinder binder = TelephonyFrameworkInitializer
                 .getTelephonyServiceManager()
diff --git a/telephony/java/android/telephony/ims/SipMessage.java b/telephony/java/android/telephony/ims/SipMessage.java
new file mode 100644
index 000000000000..c3b1be2d7fc8
--- /dev/null
+++ b/telephony/java/android/telephony/ims/SipMessage.java
@@ -0,0 +1,155 @@
+/*
+ * Copyright (C) 2020 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.telephony.ims;
+
+import android.annotation.NonNull;
+import android.os.Build;
+import android.os.Parcel;
+import android.os.Parcelable;
+
+/**
+ * Represents a partially encoded SIP message. See RFC 3261 for more information on how SIP
+ * messages are structured and used.
+ * <p>
+ * The SIP message is represented in a partially encoded form in order to allow for easier
+ * verification and should not be used as a generic SIP message container.
+ * @hide
+ */
+public final class SipMessage implements Parcelable {
+    // Should not be set to true for production!
+    private static final boolean IS_DEBUGGING = Build.IS_ENG;
+
+    private static final String[] SIP_REQUEST_METHODS = new String[] {"INVITE", "ACK", "OPTIONS",
+            "BYE", "CANCEL", "REGISTER"};
+
+    private final String mStartLine;
+    private final String mHeaderSection;
+    private final byte[] mContent;
+
+    /**
+     * Represents a partially encoded SIP message.
+     *
+     * @param startLine The start line of the message, containing either the request-line or
+     *                  status-line.
+     * @param headerSection A String containing the full unencoded SIP message header.
+     * @param content UTF-8 encoded SIP message body.
+     */
+    public SipMessage(@NonNull String startLine, @NonNull String headerSection,
+            @NonNull byte[] content) {
+        if (startLine == null || headerSection == null || content == null) {
+            throw new IllegalArgumentException("One or more null parameters entered");
+        }
+        mStartLine = startLine;
+        mHeaderSection = headerSection;
+        mContent = content;
+    }
+
+    /**
+     * Private constructor used only for unparcelling.
+     */
+    private SipMessage(Parcel source) {
+        mStartLine = source.readString();
+        mHeaderSection = source.readString();
+        mContent = new byte[source.readInt()];
+        source.readByteArray(mContent);
+    }
+    /**
+     * @return The start line of the SIP message, which contains either the request-line or
+     * status-line.
+     */
+    public @NonNull String getStartLine() {
+        return mStartLine;
+    }
+
+    /**
+     * @return The full, unencoded header section of the SIP message.
+     */
+    public @NonNull String getHeaderSection() {
+        return mHeaderSection;
+    }
+
+    /**
+     * @return only the UTF-8 encoded SIP message body.
+     */
+    public @NonNull byte[] getContent() {
+        return mContent;
+    }
+
+    @Override
+    public int describeContents() {
+        return 0;
+    }
+
+    @Override
+    public void writeToParcel(Parcel dest, int flags) {
+        dest.writeString(mStartLine);
+        dest.writeString(mHeaderSection);
+        dest.writeInt(mContent.length);
+        dest.writeByteArray(mContent);
+    }
+
+    public static final Creator<SipMessage> CREATOR = new Creator<SipMessage>() {
+        @Override
+        public SipMessage createFromParcel(Parcel source) {
+            return new SipMessage(source);
+        }
+
+        @Override
+        public SipMessage[] newArray(int size) {
+            return new SipMessage[size];
+        }
+    };
+
+    @Override
+    public String toString() {
+        StringBuilder b = new StringBuilder();
+        b.append("StartLine: [");
+        if (IS_DEBUGGING) {
+            b.append(mStartLine);
+        } else {
+            b.append(sanitizeStartLineRequest(mStartLine));
+        }
+        b.append("], [");
+        b.append("Header: [");
+        if (IS_DEBUGGING) {
+            b.append(mHeaderSection);
+        } else {
+            // only identify transaction id/call ID when it is available.
+            b.append("***");
+        }
+        b.append("], ");
+        b.append("Content: [NOT SHOWN]");
+        return b.toString();
+    }
+
+    /**
+     * Start lines containing requests are formatted: METHOD SP Request-URI SP SIP-Version CRLF.
+     * Detect if this is a REQUEST and redact Request-URI portion here, as it contains PII.
+     */
+    private String sanitizeStartLineRequest(String startLine) {
+        String[] splitLine = startLine.split(" ");
+        if (splitLine == null || splitLine.length == 0)  {
+            return "(INVALID STARTLINE)";
+        }
+        for (String method : SIP_REQUEST_METHODS) {
+            if (splitLine[0].contains(method)) {
+                return splitLine[0] + " <Request-URI> " + splitLine[2];
+            }
+        }
+        return startLine;
+    }
+}
diff --git a/telephony/java/android/telephony/ims/stub/DelegateConnectionMessageCallback.java b/telephony/java/android/telephony/ims/stub/DelegateConnectionMessageCallback.java
new file mode 100644
index 000000000000..59f9601299b2
--- /dev/null
+++ b/telephony/java/android/telephony/ims/stub/DelegateConnectionMessageCallback.java
@@ -0,0 +1,54 @@
+/*
+ * Copyright (C) 2020 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.telephony.ims.stub;
+
+import android.annotation.NonNull;
+import android.telephony.ims.SipDelegateConnection;
+import android.telephony.ims.SipDelegateManager;
+import android.telephony.ims.SipMessage;
+
+/**
+ * The callback associated with a {@link SipDelegateConnection}, which handles newly received
+ * messages as well as the result of sending a SIP message.
+ * @hide
+ */
+public interface DelegateConnectionMessageCallback {
+
+    /**
+     * A new {@link SipMessage} has been received from the delegate.
+     * @param message the {@link SipMessage} routed to this RCS application.
+     */
+    void onMessageReceived(@NonNull SipMessage message);
+
+    /**
+     * A message previously sent to the SIP delegate using
+     * {@link SipDelegateConnection#sendMessage} has been successfully sent.
+     * @param viaTransactionId The transaction ID found in the via header field of the
+     *                         previously sent {@link SipMessage}.
+     */
+    void onMessageSent(@NonNull String viaTransactionId);
+
+    /**
+     * A message previously sent to the SIP delegate using
+     * {@link SipDelegateConnection#sendMessage} has failed to be sent.
+     * @param viaTransactionId The Transaction ID found in the via header field of the
+     *                         previously sent {@link SipMessage}.
+     * @param reason The reason for the failure.
+     */
+    void onMessageSendFailure(String viaTransactionId,
+            @SipDelegateManager.MessageFailureReason int reason);
+}
diff --git a/telephony/java/android/telephony/ims/stub/DelegateConnectionStateCallback.java b/telephony/java/android/telephony/ims/stub/DelegateConnectionStateCallback.java
new file mode 100644
index 000000000000..976180538b18
--- /dev/null
+++ b/telephony/java/android/telephony/ims/stub/DelegateConnectionStateCallback.java
@@ -0,0 +1,147 @@
+/*
+ * Copyright (C) 2020 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.telephony.ims.stub;
+
+import android.annotation.NonNull;
+import android.telephony.ims.DelegateRegistrationState;
+import android.telephony.ims.DelegateRequest;
+import android.telephony.ims.FeatureTagState;
+import android.telephony.ims.SipDelegateConnection;
+import android.telephony.ims.SipDelegateImsConfiguration;
+import android.telephony.ims.SipDelegateManager;
+
+import java.util.Set;
+
+/**
+ * The callback associated with a {@link SipDelegateConnection} that manages the state of the
+ * SipDelegateConnection.
+ * <p>
+ * After {@link SipDelegateManager#createSipDelegate} is used to request a new
+ * {@link SipDelegateConnection} be created, {@link #onCreated} will be called with the
+ * {@link SipDelegateConnection} instance that must be used to communicate with the remote
+ * {@link SipDelegate}.
+ * <p>
+ * After, {@link #onFeatureTagStatusChanged} will always be called at least once with the current
+ * status of the feature tags that have been requested. The application may receive multiple
+ * {@link #onFeatureTagStatusChanged} callbacks over the lifetime of the associated
+ * {@link SipDelegateConnection}, which will signal changes to how SIP messages associated with
+ * those feature tags will be handled.
+ * <p>
+ * In order to start sending SIP messages, the SIP configuration parameters will need to be
+ * received, so the messaging application should make no assumptions about these parameters and wait
+ * until {@link #onImsConfigurationChanged(SipDelegateImsConfiguration)} has been called. This is
+ * guaranteed to happen after the first {@link #onFeatureTagStatusChanged} if there is at least one
+ * feature tag that has been successfully associated with the {@link SipDelegateConnection}. If all
+ * feature tags were denied, no IMS configuration will be sent.
+ * <p>
+ * The {@link SipDelegateConnection} will stay associated with this RCS application until either the
+ * RCS application calls {@link SipDelegateManager#destroySipDelegate} or telephony destroys the
+ * {@link SipDelegateConnection}. In both cases, {@link #onDestroyed(int)}  will be called.
+ * Telephony destroying the {@link SipDelegateConnection} instance is rare and will only happen in
+ * rare cases, such as if telephony itself or IMS service dies unexpectedly. See
+ * {@link SipDelegateManager.SipDelegateDestroyReason} reasons for more information on all of the
+ * cases that will trigger the {@link SipDelegateConnection} to be destroyed.
+ *
+ * @hide
+ */
+public interface DelegateConnectionStateCallback {
+
+    /**
+     * A {@link SipDelegateConnection} has been successfully created for the
+     * {@link DelegateRequest} used when calling {@link SipDelegateManager#createSipDelegate}.
+     */
+    void onCreated(@NonNull SipDelegateConnection c);
+
+    /**
+     * The status of the RCS feature tags that were requested as part of the initial
+     * {@link DelegateRequest}.
+     * <p>
+     * There are four states that each RCS feature tag can be in: registered, deregistering,
+     * deregistered, and denied.
+     * <p>
+     * When a feature tag is considered registered, SIP messages associated with that feature tag
+     * may be sent and received freely.
+     * <p>
+     * When a feature tag is deregistering, the network IMS registration still contains the feature
+     * tag, however the IMS service and associated {@link SipDelegate} is in the progress of
+     * modifying the IMS registration to remove this feature tag and requires the application to
+     * perform an action before the IMS registration can change. The specific action required for
+     * the SipDelegate to continue modifying the IMS registration can be found in the definition of
+     * each {@link DelegateRegistrationState.DeregisteringReason}.
+     * <p>
+     * When a feature tag is in the deregistered state, new out-of-dialog SIP messages for that
+     * feature tag will be rejected, however due to network race conditions, the RCS application
+     * should still be able to handle new out-of-dialog SIP requests from the network. This may not
+     * be possible, however, if the IMS registration itself was lost. See the
+     * {@link DelegateRegistrationState.DeregisteredReason} reasons for more information on how SIP
+     * messages are handled in each of these cases.
+     * <p>
+     * If a feature tag is denied, no incoming messages will be routed to the associated
+     * {@link DelegateConnectionMessageCallback} and all outgoing SIP messages related to this
+     * feature tag will be rejected. See {@link SipDelegateManager.DeniedReason}
+     * reasons for more information about the conditions when this will happen.
+     * <p>
+     * The set of feature tags contained in the registered, deregistering, deregistered, and denied
+     * lists will always equal the set of feature tags requested in the initial
+     * {@link DelegateRequest}.
+     * <p>
+     * Transitions of feature tags from registered, deregistering, and deregistered and vice-versa
+     * may happen quite often, however transitions to/from denied are rare and only occur if the
+     * user has changed the role of your application to add/remove support for one or more requested
+     * feature tags or carrier provisioning has enabled or disabled single registration entirely.
+     * Please see {@link SipDelegateManager.DeniedReason} reasons for an explanation of each of
+     * these cases as well as what may cause them to change.
+     *
+     * @param registrationState The new IMS registration state of each of the feature tags
+     *     associated with the {@link SipDelegate}.
+     * @param deniedFeatureTags A list of {@link FeatureTagState} objects, each containing a feature
+     *     tag associated with this {@link SipDelegateConnection} that has no access to
+     *     send/receive SIP messages as well as a reason for why the feature tag is denied. For more
+     *     information on the reason why the feature tag was denied access, see the
+     *     {@link SipDelegateManager.DeniedReason} reasons.
+     */
+    void onFeatureTagStatusChanged(@NonNull DelegateRegistrationState registrationState,
+            @NonNull Set<FeatureTagState> deniedFeatureTags);
+
+
+    /**
+     * IMS configuration of the underlying IMS stack used by this IMS application for construction
+     * of the SIP messages that will be sent over the carrier's network.
+     * <p>
+     * There should never be assumptions made about the configuration of the underling IMS stack and
+     * the IMS application should wait for this indication before sending out any outgoing SIP
+     * messages.
+     * <p>
+     * Configuration may change due to IMS registration changes as well as
+     * other optional events on the carrier network. If IMS stack is already registered at the time
+     * of callback registration, then this method shall be invoked with the current configuration.
+     * Otherwise, there may be a delay in this method being called if initial IMS registration has
+     * not compleed yet.
+     *
+     * @param registeredSipConfig The configuration of the IMS stack registered on the IMS network.
+     */
+    void onImsConfigurationChanged(@NonNull SipDelegateImsConfiguration registeredSipConfig);
+
+    /**
+     * The previously created {@link SipDelegateConnection} instance delivered via
+     * {@link #onCreated(SipDelegateConnection)} has been destroyed. This interface should no longer
+     * be used for any SIP message handling.
+     *
+     * @param reason The reason for the failure.
+     */
+    void onDestroyed(@SipDelegateManager.SipDelegateDestroyReason int reason);
+}
diff --git a/telephony/java/android/telephony/ims/stub/ImsRegistrationImplBase.java b/telephony/java/android/telephony/ims/stub/ImsRegistrationImplBase.java
index 12abdd1d7e11..a6f5c45445f5 100644
--- a/telephony/java/android/telephony/ims/stub/ImsRegistrationImplBase.java
+++ b/telephony/java/android/telephony/ims/stub/ImsRegistrationImplBase.java
@@ -17,6 +17,8 @@
 package android.telephony.ims.stub;
 
 import android.annotation.IntDef;
+import android.annotation.IntRange;
+import android.annotation.Nullable;
 import android.annotation.SystemApi;
 import android.net.Uri;
 import android.os.RemoteException;
@@ -126,6 +128,57 @@ public class ImsRegistrationImplBase {
     }
 
     /**
+     * Called by the framework to request that the ImsService perform the network registration
+     * of all SIP delegates associated with this ImsService.
+     * <p>
+     * If the SIP delegate feature tag configuration has changed, then this method will be
+     * called in order to let the ImsService know that it can pick up these changes in the IMS
+     * registration.
+     * @hide
+     */
+    public void updateSipDelegateRegistration() {
+        // Stub implementation, ImsService should implement this
+    }
+
+
+    /**
+     * Called by the framework to request that the ImsService perform the network deregistration of
+     * all SIP delegates associated with this ImsService.
+     * <p>
+     * This is typically called in situations where the user has changed the configuration of the
+     * device (for example, the default messaging application) and the framework is reconfiguring
+     * the tags associated with each IMS application.
+     * <p>
+     * This should not affect the registration of features managed by the ImsService itself, such as
+     * feature tags related to MMTEL registration.
+     * @hide
+     */
+    public void triggerSipDelegateDeregistration() {
+        // Stub implementation, ImsService should implement this
+    }
+
+    /**
+     * Called by the framework to notify the ImsService that a SIP delegate connection has received
+     * a SIP message containing a permanent failure response (such as a 403) or an indication that a
+     * SIP response timer has timed out in response to an outgoing SIP message. This method will be
+     * called when this condition occurs to trigger the ImsService to tear down the full IMS
+     * registration and re-register again.
+     *
+     * @param sipCode The SIP error code that represents a permanent failure that was received in
+     *    response to a request generated by the IMS application. See RFC3261 7.2 for the general
+     *    classes of responses available here, however the codes that generate this condition may
+     *    be carrier specific.
+     * @param sipReason The reason associated with the SIP error code. {@code null} if there was no
+     *    reason associated with the error.
+     * @hide
+     */
+    public void triggerNetworkReregistration(@IntRange(from = 100, to = 699) int sipCode,
+            @Nullable String sipReason) {
+        // Stub implementation, ImsService should implement this
+    }
+
+
+    /**
      * Notify the framework that the device is connected to the IMS network.
      *
      * @param imsRadioTech the radio access technology. Valid values are defined as
diff --git a/telephony/java/android/telephony/ims/stub/SipDelegate.java b/telephony/java/android/telephony/ims/stub/SipDelegate.java
new file mode 100644
index 000000000000..3ec97095eb00
--- /dev/null
+++ b/telephony/java/android/telephony/ims/stub/SipDelegate.java
@@ -0,0 +1,91 @@
+/*
+ * Copyright (C) 2020 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.telephony.ims.stub;
+
+import android.annotation.NonNull;
+import android.telephony.ims.DelegateMessageCallback;
+import android.telephony.ims.ImsService;
+import android.telephony.ims.SipDelegateImsConfiguration;
+import android.telephony.ims.SipDelegateManager;
+import android.telephony.ims.SipMessage;
+
+/**
+ * The {@link SipDelegate} is implemented by the {@link ImsService} and allows a privileged
+ * IMS application to use this delegate to send SIP messages as well as acknowledge the receipt of
+ * incoming SIP messages delivered to the application over the existing IMS registration, allowing
+ * for a single IMS registration for multiple IMS applications.
+ * <p>
+ * Once the SIP delegate is created for that application,
+ * {@link ImsRegistrationImplBase#updateSipDelegateRegistration()} will be called, indicating that
+ * the application is finished setting up SipDelegates and the existing IMS registration may be
+ * modified to include the features managed by these SipDelegates.
+ * <p>
+ * This SipDelegate will need to notify the remote application of the registration of these features
+ * as well as the associated {@link SipDelegateImsConfiguration} before the application can start
+ * sending/receiving SIP messages via the transport. See
+ * {@link android.telephony.ims.DelegateStateCallback} for more information.
+ * @hide
+ */
+public interface SipDelegate {
+
+    /**
+     * The framework calls this method when a remote RCS application wishes to send a new outgoing
+     * SIP message.
+     * <p>
+     * Once sent, this SIP delegate should notify the remote application of the success or
+     * failure using {@link DelegateMessageCallback#onMessageSent(String)} or
+     * {@link DelegateMessageCallback#onMessageSendFailure(String, int)}.
+     * @param message The SIP message to be sent over the operator’s network.
+     * @param configVersion The SipDelegateImsConfiguration version used to construct the
+     *         SipMessage. See {@link SipDelegateImsConfiguration} for more information. If the
+     *         version specified here does not match the most recently constructed
+     *         {@link SipDelegateImsConfiguration}, this message should fail validation checks and
+     *         {@link DelegateMessageCallback#onMessageSendFailure} should be called with code
+     *         {@link SipDelegateManager#MESSAGE_FAILURE_REASON_STALE_IMS_CONFIGURATION}.
+     */
+    void sendMessage(@NonNull SipMessage message, int configVersion);
+
+    /**
+     * The framework is requesting that routing resources associated with the SIP dialog using the
+     * provided Call-ID to be cleaned up.
+     * <p>
+     * Typically a SIP Dialog close event will be signalled by that dialog receiving a BYE or 200 OK
+     * message, however, in some cases, the framework will request that the ImsService close the
+     * dialog due to the open dialog holding up an event such as applying a provisioning change or
+     * handing over to another transport type.
+     * @param callId The call-ID header value associated with the ongoing SIP Dialog that the
+     *         framework is requesting be closed.
+     */
+    void closeDialog(@NonNull String callId);
+
+    /**
+     * The remote application has received the SIP message and is processing it.
+     * @param viaTransactionId The Transaction ID found in the via header field of the
+     *                         previously sent {@link SipMessage}.
+     */
+    void notifyMessageReceived(@NonNull String viaTransactionId);
+
+    /**
+     * The remote application has either not received the SIP message or there was an error
+     * processing it.
+     * @param viaTransactionId The Transaction ID found in the via header field of the
+     *                         previously sent {@link SipMessage}.
+     * @param reason The reason why the message was not correctly received.
+     */
+    void notifyMessageReceiveError(@NonNull String viaTransactionId,
+            @SipDelegateManager.MessageFailureReason int reason);
+}
diff --git a/telephony/java/android/telephony/ims/stub/SipTransportImplBase.java b/telephony/java/android/telephony/ims/stub/SipTransportImplBase.java
index b2b2914b3739..8b0fde6b6bf2 100644
--- a/telephony/java/android/telephony/ims/stub/SipTransportImplBase.java
+++ b/telephony/java/android/telephony/ims/stub/SipTransportImplBase.java
@@ -18,13 +18,21 @@ package android.telephony.ims.stub;
 
 import android.annotation.NonNull;
 import android.annotation.SystemApi;
+import android.telephony.ims.DelegateMessageCallback;
+import android.telephony.ims.DelegateRequest;
+import android.telephony.ims.DelegateStateCallback;
+import android.telephony.ims.SipDelegateManager;
 import android.telephony.ims.aidl.ISipTransport;
 
 import java.util.concurrent.Executor;
 
 /**
- * Manages the creation and destruction of SipDelegates in order to proxy SIP traffic to other
- * IMS applications in order to support IMS single registration.
+ * The ImsService implements this class to manage the creation and destruction of
+ * {@link SipDelegate}s.
+ *
+ * {@link SipDelegate}s allow the ImsService to forward SIP traffic generated and consumed by IMS
+ * applications as a delegate to the associated carrier's IMS Network in order to support using a
+ * single IMS registration for all MMTEL and RCS signalling traffic.
  * @hide
  */
 @SystemApi
@@ -49,6 +57,36 @@ public class SipTransportImplBase {
     }
 
     /**
+     * The ImsService implements this method to handle requests to create a new {@link SipDelegate}
+     * for subscription associated with it.
+     *
+     * @param request A SIP delegate request containing the parameters that the remote RCS
+     * application wishes to use.
+     * @param dc A callback back to the remote application to be used to communicate state callbacks
+     *           for the SipDelegate.
+     * @param mc A callback back to the remote application to be used to send SIP messages to the
+     *           remote application and acknowledge the sending of outgoing SIP messages.
+     * @hide
+     */
+    public void createSipDelegate(@NonNull DelegateRequest request,
+            @NonNull DelegateStateCallback dc, @NonNull DelegateMessageCallback mc) {
+
+    }
+
+    /**
+     * Destroys the SipDelegate associated with a remote IMS application. After the delegate is
+     * destroyed, SipDelegate#onDestroy should be called to notify listeners of its destruction to
+     * release resources.
+     * @param delegate The delegate to be modified.
+     * @param reason The reason the remote connection to this SipDelegate is being destroyed.
+     * @hide
+     */
+    public void destroySipDelegate(@NonNull SipDelegate delegate,
+            @SipDelegateManager.SipDelegateDestroyReason int reason) {
+
+    }
+
+    /**
      * @return The IInterface used by the framework.
      * @hide
      */