Merge "Support adding an IPv4 address via RTM_NEWADDR netlink message." into main
diff --git a/staticlibs/device/com/android/net/module/util/netlink/NetlinkUtils.java b/staticlibs/device/com/android/net/module/util/netlink/NetlinkUtils.java
index 7c2be2c..f735e46 100644
--- a/staticlibs/device/com/android/net/module/util/netlink/NetlinkUtils.java
+++ b/staticlibs/device/com/android/net/module/util/netlink/NetlinkUtils.java
@@ -29,6 +29,7 @@
 import static android.system.OsConstants.SO_RCVBUF;
 import static android.system.OsConstants.SO_RCVTIMEO;
 import static android.system.OsConstants.SO_SNDTIMEO;
+
 import static com.android.net.module.util.netlink.NetlinkConstants.hexify;
 import static com.android.net.module.util.netlink.NetlinkConstants.NLMSG_DONE;
 import static com.android.net.module.util.netlink.NetlinkConstants.RTNL_FAMILY_IP6MR;
@@ -49,6 +50,7 @@
 import java.io.IOException;
 import java.io.InterruptedIOException;
 import java.net.Inet6Address;
+import java.net.InetAddress;
 import java.net.SocketException;
 import java.nio.ByteBuffer;
 import java.nio.ByteOrder;
@@ -56,7 +58,6 @@
 import java.util.List;
 import java.util.Objects;
 import java.util.function.Consumer;
-import java.util.stream.Collectors;
 
 /**
  * Utilities for netlink related class that may not be able to fit into a specific class.
@@ -177,19 +178,19 @@
     }
 
     /**
-     * Send an RTM_NEWADDR message to kernel to add or update an IPv6 address.
+     * Send an RTM_NEWADDR message to kernel to add or update an IP address.
      *
      * @param ifIndex interface index.
-     * @param ip IPv6 address to be added.
-     * @param prefixlen IPv6 address prefix length.
-     * @param flags IPv6 address flags.
-     * @param scope IPv6 address scope.
-     * @param preferred The preferred lifetime of IPv6 address.
-     * @param valid The valid lifetime of IPv6 address.
+     * @param ip IP address to be added.
+     * @param prefixlen IP address prefix length.
+     * @param flags IP address flags.
+     * @param scope IP address scope.
+     * @param preferred The preferred lifetime of IP address.
+     * @param valid The valid lifetime of IP address.
      */
-    public static boolean sendRtmNewAddressRequest(int ifIndex, @NonNull final Inet6Address ip,
+    public static boolean sendRtmNewAddressRequest(int ifIndex, @NonNull final InetAddress ip,
             short prefixlen, int flags, byte scope, long preferred, long valid) {
-        Objects.requireNonNull(ip, "IPv6 address to be added should not be null.");
+        Objects.requireNonNull(ip, "IP address to be added should not be null.");
         final byte[] msg = RtNetlinkAddressMessage.newRtmNewAddressMessage(1 /* seqNo*/, ip,
                 prefixlen, flags, scope, ifIndex, preferred, valid);
         try {
diff --git a/staticlibs/device/com/android/net/module/util/netlink/RtNetlinkAddressMessage.java b/staticlibs/device/com/android/net/module/util/netlink/RtNetlinkAddressMessage.java
index cbe0ab0..4846df7 100644
--- a/staticlibs/device/com/android/net/module/util/netlink/RtNetlinkAddressMessage.java
+++ b/staticlibs/device/com/android/net/module/util/netlink/RtNetlinkAddressMessage.java
@@ -16,6 +16,7 @@
 
 package com.android.net.module.util.netlink;
 
+import static com.android.net.module.util.Inet4AddressUtils.getBroadcastAddress;
 import static com.android.net.module.util.netlink.StructNlMsgHdr.NLM_F_ACK;
 import static com.android.net.module.util.netlink.StructNlMsgHdr.NLM_F_REPLACE;
 import static com.android.net.module.util.netlink.StructNlMsgHdr.NLM_F_REQUEST;
@@ -28,6 +29,7 @@
 
 import com.android.net.module.util.HexDump;
 
+import java.net.Inet4Address;
 import java.net.Inet6Address;
 import java.net.InetAddress;
 import java.nio.ByteBuffer;
@@ -48,6 +50,8 @@
  */
 public class RtNetlinkAddressMessage extends NetlinkMessage {
     public static final short IFA_ADDRESS        = 1;
+    public static final short IFA_LOCAL          = 2;
+    public static final short IFA_BROADCAST      = 4;
     public static final short IFA_CACHEINFO      = 6;
     public static final short IFA_FLAGS          = 8;
 
@@ -71,6 +75,7 @@
         mIfacacheInfo = structIfacacheInfo;
         mFlags = flags;
     }
+
     private RtNetlinkAddressMessage(@NonNull StructNlMsgHdr header) {
         this(header, null, null, null, 0);
     }
@@ -158,6 +163,24 @@
         // still be packed to ByteBuffer even if the flag is 0.
         final StructNlAttr flags = new StructNlAttr(IFA_FLAGS, mFlags);
         flags.pack(byteBuffer);
+
+        // Add the required IFA_LOCAL and IFA_BROADCAST attributes for IPv4 addresses. The IFA_LOCAL
+        // attribute represents the local address, which is equivalent to IFA_ADDRESS on a normally
+        // configured broadcast interface, however, for PPP interfaces, IFA_ADDRESS indicates the
+        // destination address and the local address is provided in the IFA_LOCAL attribute. If the
+        // IFA_LOCAL attribute is not present in the RTM_NEWADDR message, the kernel replies with an
+        // error netlink message with invalid parameters. IFA_BROADCAST is also required, otherwise
+        // the broadcast on the interface is 0.0.0.0. See include/uapi/linux/if_addr.h for details.
+        // For IPv6 addresses, the IFA_ADDRESS attribute applies and introduces no ambiguity.
+        if (mIpAddress instanceof Inet4Address) {
+            final StructNlAttr localAddress = new StructNlAttr(IFA_LOCAL, mIpAddress);
+            localAddress.pack(byteBuffer);
+
+            final Inet4Address broadcast =
+                    getBroadcastAddress((Inet4Address) mIpAddress, mIfaddrmsg.prefixLen);
+            final StructNlAttr broadcastAddress = new StructNlAttr(IFA_BROADCAST, broadcast);
+            broadcastAddress.pack(byteBuffer);
+        }
     }
 
     /**
@@ -184,7 +207,7 @@
                 0 /* tstamp */);
         msg.mFlags = flags;
 
-        final byte[] bytes = new byte[msg.getRequiredSpace()];
+        final byte[] bytes = new byte[msg.getRequiredSpace(family)];
         nlmsghdr.nlmsg_len = bytes.length;
         final ByteBuffer byteBuffer = ByteBuffer.wrap(bytes);
         byteBuffer.order(ByteOrder.nativeOrder());
@@ -237,7 +260,7 @@
     // RtNetlinkAddressMessage, e.g. RTM_DELADDR sent from user space to kernel to delete an
     // IP address only requires IFA_ADDRESS attribute. The caller should check if these attributes
     // are necessary to carry when constructing a RtNetlinkAddressMessage.
-    private int getRequiredSpace() {
+    private int getRequiredSpace(int family) {
         int spaceRequired = StructNlMsgHdr.STRUCT_SIZE + StructIfaddrMsg.STRUCT_SIZE;
         // IFA_ADDRESS attr
         spaceRequired += NetlinkConstants.alignedLengthOf(
@@ -247,6 +270,14 @@
                 StructNlAttr.NLA_HEADERLEN + StructIfacacheInfo.STRUCT_SIZE);
         // IFA_FLAGS "u32" attr
         spaceRequired += StructNlAttr.NLA_HEADERLEN + 4;
+        if (family == OsConstants.AF_INET) {
+            // IFA_LOCAL attr
+            spaceRequired += NetlinkConstants.alignedLengthOf(
+                    StructNlAttr.NLA_HEADERLEN + mIpAddress.getAddress().length);
+            // IFA_BROADCAST attr
+            spaceRequired += NetlinkConstants.alignedLengthOf(
+                    StructNlAttr.NLA_HEADERLEN + mIpAddress.getAddress().length);
+        }
         return spaceRequired;
     }
 
diff --git a/staticlibs/tests/unit/src/com/android/net/module/util/netlink/RtNetlinkAddressMessageTest.java b/staticlibs/tests/unit/src/com/android/net/module/util/netlink/RtNetlinkAddressMessageTest.java
index 01126d2..1d08525 100644
--- a/staticlibs/tests/unit/src/com/android/net/module/util/netlink/RtNetlinkAddressMessageTest.java
+++ b/staticlibs/tests/unit/src/com/android/net/module/util/netlink/RtNetlinkAddressMessageTest.java
@@ -42,6 +42,7 @@
 import org.junit.Test;
 import org.junit.runner.RunWith;
 
+import java.net.Inet4Address;
 import java.net.Inet6Address;
 import java.nio.ByteBuffer;
 import java.nio.ByteOrder;
@@ -179,6 +180,57 @@
     }
 
     @Test
+    public void testCreateRtmNewAddressMessage_IPv4Address() {
+        // Hexadecimal representation of our created packet.
+        final String expectedNewAddressHex =
+                // struct nlmsghdr
+                "4c000000"      // length = 76
+                + "1400"        // type = 20 (RTM_NEWADDR)
+                + "0501"        // flags = NLM_F_ACK | NLM_F_REQUEST | NLM_F_REPLACE
+                + "01000000"    // seqno = 1
+                + "00000000"    // pid = 0 (send to kernel)
+                // struct IfaddrMsg
+                + "02"          // family = inet
+                + "18"          // prefix len = 24
+                + "00"          // flags = 0
+                + "00"          // scope = RT_SCOPE_UNIVERSE
+                + "14000000"    // ifindex = 20
+                // struct nlattr: IFA_ADDRESS
+                + "0800"        // len
+                + "0100"        // type
+                + "C0A80491"    // IPv4 address = 192.168.4.145
+                // struct nlattr: IFA_CACHEINFO
+                + "1400"        // len
+                + "0600"        // type
+                + "C0A80000"    // preferred = 43200s
+                + "C0A80000"    // valid = 43200s
+                + "00000000"    // cstamp
+                + "00000000"    // tstamp
+                // struct nlattr: IFA_FLAGS
+                + "0800"        // len
+                + "0800"        // type
+                + "00000000"    // flags = 0
+                // struct nlattr: IFA_LOCAL
+                + "0800"        // len
+                + "0200"        // type
+                + "C0A80491"    // local address = 192.168.4.145
+                // struct nlattr: IFA_BROADCAST
+                + "0800"        // len
+                + "0400"        // type
+                + "C0A804FF";   // broadcast address = 192.168.4.255
+        final byte[] expectedNewAddress =
+                HexEncoding.decode(expectedNewAddressHex.toCharArray(), false);
+
+        final Inet4Address ipAddress =
+                (Inet4Address) InetAddresses.parseNumericAddress("192.168.4.145");
+        final byte[] bytes = RtNetlinkAddressMessage.newRtmNewAddressMessage(1 /* seqno */,
+                ipAddress, (short) 24 /* prefix len */, 0 /* flags */,
+                (byte) RT_SCOPE_UNIVERSE /* scope */, 20 /* ifindex */,
+                (long) 0xA8C0 /* preferred */, (long) 0xA8C0 /* valid */);
+        assertArrayEquals(expectedNewAddress, bytes);
+    }
+
+    @Test
     public void testCreateRtmDelAddressMessage() {
         // Hexadecimal representation of our created packet.
         final String expectedDelAddressHex =