Expose public APIs for IP & static IP configuration

Create public API for IP and static IP configuration.

Bug: 209840828
Test: atest android.net.cts.IpConfigurationTest
Test: atest android.net.cts.StaticIpConfigurationTest
Test: atest android.net.dhcp.DhcpResultsParcelableUtilTest
Change-Id: I720f168d1023806970919ca5dd44239a276826b6

framework/src/android/net/StaticIpConfiguration.java

@@ -26,6 +26,7 @@ import android.os.Parcelable;
 
 import com.android.net.module.util.InetAddressUtils;
 
+import java.net.Inet4Address;
 import java.net.InetAddress;
 import java.util.ArrayList;
 import java.util.List;
@@ -33,24 +34,7 @@ import java.util.Objects;
 
 /**
  * Class that describes static IP configuration.
- *
- * <p>This class is different from {@link LinkProperties} because it represents
- * configuration intent. The general contract is that if we can represent
- * a configuration here, then we should be able to configure it on a network.
- * The intent is that it closely match the UI we have for configuring networks.
- *
- * <p>In contrast, {@link LinkProperties} represents current state. It is much more
- * expressive. For example, it supports multiple IP addresses, multiple routes,
- * stacked interfaces, and so on. Because LinkProperties is so expressive,
- * using it to represent configuration intent as well as current state causes
- * problems. For example, we could unknowingly save a configuration that we are
- * not in fact capable of applying, or we could save a configuration that the
- * UI cannot display, which has the potential for malicious code to hide
- * hostile or unexpected configuration from the user.
- *
- * @hide
  */
-@SystemApi
 public final class StaticIpConfiguration implements Parcelable {
     /** @hide */
     @UnsupportedAppUsage(maxTargetSdk = Build.VERSION_CODES.R, trackingBug = 170729553)
@@ -69,10 +53,14 @@ public final class StaticIpConfiguration implements Parcelable {
     @Nullable
     public String domains;
 
+    /** @hide */
+    @SystemApi
     public StaticIpConfiguration() {
         dnsServers = new ArrayList<>();
     }
 
+    /** @hide */
+    @SystemApi
     public StaticIpConfiguration(@Nullable StaticIpConfiguration source) {
         this();
         if (source != null) {
@@ -84,6 +72,8 @@ public final class StaticIpConfiguration implements Parcelable {
         }
     }
 
+    /** @hide */
+    @SystemApi
     public void clear() {
         ipAddress = null;
         gateway = null;
@@ -94,7 +84,7 @@ public final class StaticIpConfiguration implements Parcelable {
     /**
      * Get the static IP address included in the configuration.
      */
-    public @Nullable LinkAddress getIpAddress() {
+    public @NonNull LinkAddress getIpAddress() {
         return ipAddress;
     }
 
@@ -130,10 +120,15 @@ public final class StaticIpConfiguration implements Parcelable {
         private String mDomains;
 
         /**
-         * Set the IP address to be included in the configuration; null by default.
+         * Set the IP address to be included in the configuration.
+         *
          * @return The {@link Builder} for chaining.
          */
-        public @NonNull Builder setIpAddress(@Nullable LinkAddress ipAddress) {
+        public @NonNull Builder setIpAddress(@NonNull LinkAddress ipAddress) {
+            if (ipAddress != null && !(ipAddress.getAddress() instanceof Inet4Address)) {
+                throw new IllegalArgumentException(
+                        "Only IPv4 addresses can be used for the IP configuration");
+            }
             mIpAddress = ipAddress;
             return this;
         }
@@ -143,6 +138,10 @@ public final class StaticIpConfiguration implements Parcelable {
          * @return The {@link Builder} for chaining.
          */
         public @NonNull Builder setGateway(@Nullable InetAddress gateway) {
+            if (gateway != null && !(gateway instanceof Inet4Address)) {
+                throw new IllegalArgumentException(
+                        "Only IPv4 addresses can be used for the gateway configuration");
+            }
             mGateway = gateway;
             return this;
         }
@@ -153,6 +152,12 @@ public final class StaticIpConfiguration implements Parcelable {
          */
         public @NonNull Builder setDnsServers(@NonNull Iterable<InetAddress> dnsServers) {
             Objects.requireNonNull(dnsServers);
+            for (InetAddress inetAddress: dnsServers) {
+                if (!(inetAddress instanceof Inet4Address)) {
+                    throw new IllegalArgumentException(
+                            "Only IPv4 addresses can be used for the DNS server configuration");
+                }
+            }
             mDnsServers = dnsServers;
             return this;
         }
@@ -171,6 +176,8 @@ public final class StaticIpConfiguration implements Parcelable {
         /**
          * Create a {@link StaticIpConfiguration} from the parameters in this {@link Builder}.
          * @return The newly created StaticIpConfiguration.
+         * @throws IllegalArgumentException if an invalid configuration is attempted, e.g.
+         * if an IP Address was not configured via {@link #setIpAddress(LinkAddress)}.
          */
         public @NonNull StaticIpConfiguration build() {
             final StaticIpConfiguration config = new StaticIpConfiguration();
@@ -188,7 +195,9 @@ public final class StaticIpConfiguration implements Parcelable {
 
     /**
      * Add a DNS server to this configuration.
+     * @hide
      */
+    @SystemApi
     public void addDnsServer(@NonNull InetAddress server) {
         dnsServers.add(server);
     }
@@ -197,7 +206,9 @@ public final class StaticIpConfiguration implements Parcelable {
      * Returns the network routes specified by this object. Will typically include a
      * directly-connected route for the IP address's local subnet and a default route.
      * @param iface Interface to include in the routes.
+     * @hide
      */
+    @SystemApi
     public @NonNull List<RouteInfo> getRoutes(@Nullable String iface) {
         List<RouteInfo> routes = new ArrayList<RouteInfo>(3);
         if (ipAddress != null) {
@@ -305,7 +316,7 @@ public final class StaticIpConfiguration implements Parcelable {
 
     /** Implement the Parcelable interface */
     @Override
-    public void writeToParcel(Parcel dest, int flags) {
+    public void writeToParcel(@NonNull Parcel dest, int flags) {
         dest.writeParcelable(ipAddress, flags);
         InetAddressUtils.parcelInetAddress(dest, gateway, flags);
         dest.writeInt(dnsServers.size());
@@ -316,7 +327,7 @@ public final class StaticIpConfiguration implements Parcelable {
     }
 
     /** @hide */
-    public static StaticIpConfiguration readFromParcel(Parcel in) {
+    public static @NonNull StaticIpConfiguration readFromParcel(Parcel in) {
         final StaticIpConfiguration s = new StaticIpConfiguration();
         s.ipAddress = in.readParcelable(null);
         s.gateway = InetAddressUtils.unparcelInetAddress(in);