[Tether03] Migrate IpServer into module

Add IpServer which is used to serve ip configuration, dhcp, dns proxy
and nat for downstream interface.

Bug: 136040414
Test: -build, flash, boot
      -atest TetheringTests
      -atest FrameworksNetTests

Change-Id: I23652ae0b9509abe7d38da96d523eb22ab00a343

Tethering/src/android/net/dhcp/DhcpServingParamsParcelExt.java

@@ -0,0 +1,172 @@
+/*
+ * Copyright (C) 2018 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package android.net.dhcp;
+
+import static android.net.shared.Inet4AddressUtils.inet4AddressToIntHTH;
+
+import android.annotation.NonNull;
+import android.net.LinkAddress;
+
+import com.google.android.collect.Sets;
+
+import java.net.Inet4Address;
+import java.util.Collection;
+import java.util.Set;
+
+/**
+ * Subclass of {@link DhcpServingParamsParcel} with additional utility methods for building.
+ *
+ * <p>This utility class does not check for validity of the parameters: invalid parameters are
+ * reported by the receiving module when unparceling the parcel.
+ *
+ * @see DhcpServingParams
+ * @hide
+ */
+public class DhcpServingParamsParcelExt extends DhcpServingParamsParcel {
+    public static final int MTU_UNSET = 0;
+
+    /**
+     * Set the server address and served prefix for the DHCP server.
+     *
+     * <p>This parameter is required.
+     */
+    public DhcpServingParamsParcelExt setServerAddr(@NonNull LinkAddress serverAddr) {
+        this.serverAddr = inet4AddressToIntHTH((Inet4Address) serverAddr.getAddress());
+        this.serverAddrPrefixLength = serverAddr.getPrefixLength();
+        return this;
+    }
+
+    /**
+     * Set the default routers to be advertised to DHCP clients.
+     *
+     * <p>Each router must be inside the served prefix. This may be an empty set, but it must
+     * always be set explicitly.
+     */
+    public DhcpServingParamsParcelExt setDefaultRouters(@NonNull Set<Inet4Address> defaultRouters) {
+        this.defaultRouters = toIntArray(defaultRouters);
+        return this;
+    }
+
+    /**
+     * Set the default routers to be advertised to DHCP clients.
+     *
+     * <p>Each router must be inside the served prefix. This may be an empty list of routers,
+     * but it must always be set explicitly.
+     */
+    public DhcpServingParamsParcelExt setDefaultRouters(@NonNull Inet4Address... defaultRouters) {
+        return setDefaultRouters(Sets.newArraySet(defaultRouters));
+    }
+
+    /**
+     * Convenience method to build the parameters with no default router.
+     *
+     * <p>Equivalent to calling {@link #setDefaultRouters(Inet4Address...)} with no address.
+     */
+    public DhcpServingParamsParcelExt setNoDefaultRouter() {
+        return setDefaultRouters();
+    }
+
+    /**
+     * Set the DNS servers to be advertised to DHCP clients.
+     *
+     * <p>This may be an empty set, but it must always be set explicitly.
+     */
+    public DhcpServingParamsParcelExt setDnsServers(@NonNull Set<Inet4Address> dnsServers) {
+        this.dnsServers = toIntArray(dnsServers);
+        return this;
+    }
+
+    /**
+     * Set the DNS servers to be advertised to DHCP clients.
+     *
+     * <p>This may be an empty list of servers, but it must always be set explicitly.
+     */
+    public DhcpServingParamsParcelExt setDnsServers(@NonNull Inet4Address... dnsServers) {
+        return setDnsServers(Sets.newArraySet(dnsServers));
+    }
+
+    /**
+     * Convenience method to build the parameters with no DNS server.
+     *
+     * <p>Equivalent to calling {@link #setDnsServers(Inet4Address...)} with no address.
+     */
+    public DhcpServingParamsParcelExt setNoDnsServer() {
+        return setDnsServers();
+    }
+
+    /**
+     * Set excluded addresses that the DHCP server is not allowed to assign to clients.
+     *
+     * <p>This parameter is optional. DNS servers and default routers are always excluded
+     * and do not need to be set here.
+     */
+    public DhcpServingParamsParcelExt setExcludedAddrs(@NonNull Set<Inet4Address> excludedAddrs) {
+        this.excludedAddrs = toIntArray(excludedAddrs);
+        return this;
+    }
+
+    /**
+     * Set excluded addresses that the DHCP server is not allowed to assign to clients.
+     *
+     * <p>This parameter is optional. DNS servers and default routers are always excluded
+     * and do not need to be set here.
+     */
+    public DhcpServingParamsParcelExt setExcludedAddrs(@NonNull Inet4Address... excludedAddrs) {
+        return setExcludedAddrs(Sets.newArraySet(excludedAddrs));
+    }
+
+    /**
+     * Set the lease time for leases assigned by the DHCP server.
+     *
+     * <p>This parameter is required.
+     */
+    public DhcpServingParamsParcelExt setDhcpLeaseTimeSecs(long dhcpLeaseTimeSecs) {
+        this.dhcpLeaseTimeSecs = dhcpLeaseTimeSecs;
+        return this;
+    }
+
+    /**
+     * Set the link MTU to be advertised to DHCP clients.
+     *
+     * <p>If set to {@link #MTU_UNSET}, no MTU will be advertised to clients. This parameter
+     * is optional and defaults to {@link #MTU_UNSET}.
+     */
+    public DhcpServingParamsParcelExt setLinkMtu(int linkMtu) {
+        this.linkMtu = linkMtu;
+        return this;
+    }
+
+    /**
+     * Set whether the DHCP server should send the ANDROID_METERED vendor-specific option.
+     *
+     * <p>If not set, the default value is false.
+     */
+    public DhcpServingParamsParcelExt setMetered(boolean metered) {
+        this.metered = metered;
+        return this;
+    }
+
+    private static int[] toIntArray(@NonNull Collection<Inet4Address> addrs) {
+        int[] res = new int[addrs.size()];
+        int i = 0;
+        for (Inet4Address addr : addrs) {
+            res[i] = inet4AddressToIntHTH(addr);
+            i++;
+        }
+        return res;
+    }
+}