Move attach*Filter() and addArpEntry() methods to NetworkStack

The SocketUtils.attach*Filter and SocketUtils.addArpEntry methods
were added there because they could not be added as JNI inside
the NetworkStack. This was not possible because on Go devices,
the NetworkStack was a jar library. But now, Go also uses an APK.
Hence, move these methods to the NetworkStack.

Fixes: 129433183
Merged-In: I66d7b3e4fbfa32bb0bc853e8cf9399031daff8a9
(cherry picked from commit fe71be2b04a3213828dc0347a1dd4a3675d20562)

Change-Id: Ice433a41469e784385f19498c154345d7b9c69b5

5 files changed, 47 insertions, 7 deletions

diff --git a/src/android/net/apf/ApfFilter.java b/src/android/net/apf/ApfFilter.java
index d2f3259..663e2f1 100644
--- a/src/android/net/apf/ApfFilter.java
+++ b/src/android/net/apf/ApfFilter.java
@@ -49,7 +49,6 @@ import android.net.metrics.IpConnectivityLog;
 import android.net.metrics.RaEvent;
 import android.net.util.InterfaceParams;
 import android.net.util.NetworkStackUtils;
-import android.net.util.SocketUtils;
 import android.os.PowerManager;
 import android.os.SystemClock;
 import android.system.ErrnoException;
@@ -478,7 +477,7 @@ public class ApfFilter {
             SocketAddress addr = makePacketSocketAddress(
                     (short) ETH_P_IPV6, mInterfaceParams.index);
             Os.bind(socket, addr);
-            SocketUtils.attachRaFilter(socket, mApfCapabilities.apfPacketFormat);
+            NetworkStackUtils.attachRaFilter(socket, mApfCapabilities.apfPacketFormat);
         } catch(SocketException|ErrnoException e) {
             Log.e(TAG, "Error starting filter", e);
             return;
diff --git a/src/android/net/dhcp/DhcpClient.java b/src/android/net/dhcp/DhcpClient.java
index 79d6a55..64adc0d 100644
--- a/src/android/net/dhcp/DhcpClient.java
+++ b/src/android/net/dhcp/DhcpClient.java
@@ -51,6 +51,7 @@ import android.net.metrics.DhcpClientEvent;
 import android.net.metrics.DhcpErrorEvent;
 import android.net.metrics.IpConnectivityLog;
 import android.net.util.InterfaceParams;
+import android.net.util.NetworkStackUtils;
 import android.net.util.SocketUtils;
 import android.os.Message;
 import android.os.SystemClock;
@@ -319,7 +320,7 @@ public class DhcpClient extends StateMachine {
             mPacketSock = Os.socket(AF_PACKET, SOCK_RAW, ETH_P_IP);
             SocketAddress addr = makePacketSocketAddress((short) ETH_P_IP, mIface.index);
             Os.bind(mPacketSock, addr);
-            SocketUtils.attachDhcpFilter(mPacketSock);
+            NetworkStackUtils.attachDhcpFilter(mPacketSock);
         } catch(SocketException|ErrnoException e) {
             Log.e(TAG, "Error creating packet socket", e);
             return false;
diff --git a/src/android/net/dhcp/DhcpServer.java b/src/android/net/dhcp/DhcpServer.java
index cd993e9..8832eaa 100644
--- a/src/android/net/dhcp/DhcpServer.java
+++ b/src/android/net/dhcp/DhcpServer.java
@@ -45,6 +45,7 @@ import android.annotation.Nullable;
 import android.net.INetworkStackStatusCallback;
 import android.net.MacAddress;
 import android.net.TrafficStats;
+import android.net.util.NetworkStackUtils;
 import android.net.util.SharedLog;
 import android.net.util.SocketUtils;
 import android.os.Handler;
@@ -207,7 +208,7 @@ public class DhcpServer extends IDhcpServer.Stub {
         @Override
         public void addArpEntry(@NonNull Inet4Address ipv4Addr, @NonNull MacAddress ethAddr,
                 @NonNull String ifname, @NonNull FileDescriptor fd) throws IOException {
-            SocketUtils.addArpEntry(ipv4Addr, ethAddr, ifname, fd);
+            NetworkStackUtils.addArpEntry(ipv4Addr, ethAddr, ifname, fd);
         }
 
         @Override
diff --git a/src/android/net/ip/ConnectivityPacketTracker.java b/src/android/net/ip/ConnectivityPacketTracker.java
index de54824..eb49218 100644
--- a/src/android/net/ip/ConnectivityPacketTracker.java
+++ b/src/android/net/ip/ConnectivityPacketTracker.java
@@ -25,8 +25,8 @@ import static android.system.OsConstants.SOCK_RAW;
 
 import android.net.util.ConnectivityPacketSummary;
 import android.net.util.InterfaceParams;
+import android.net.util.NetworkStackUtils;
 import android.net.util.PacketReader;
-import android.net.util.SocketUtils;
 import android.os.Handler;
 import android.system.ErrnoException;
 import android.system.Os;
@@ -103,7 +103,7 @@ public class ConnectivityPacketTracker {
             FileDescriptor s = null;
             try {
                 s = Os.socket(AF_PACKET, SOCK_RAW | SOCK_NONBLOCK, 0);
-                SocketUtils.attachControlPacketFilter(s, ARPHRD_ETHER);
+                NetworkStackUtils.attachControlPacketFilter(s, ARPHRD_ETHER);
                 Os.bind(s, makePacketSocketAddress((short) ETH_P_ALL, mInterface.index));
             } catch (ErrnoException | IOException e) {
                 logError("Failed to create packet tracking socket: ", e);
diff --git a/src/android/net/util/NetworkStackUtils.java b/src/android/net/util/NetworkStackUtils.java
index 9d2df57..dada61c 100644
--- a/src/android/net/util/NetworkStackUtils.java
+++ b/src/android/net/util/NetworkStackUtils.java
@@ -23,14 +23,18 @@ import android.util.SparseArray;
 
 import java.io.FileDescriptor;
 import java.io.IOException;
+import java.net.Inet4Address;
+import java.net.SocketException;
 import java.util.List;
 import java.util.function.Predicate;
 
-
 /**
  * Collection of utilities for the network stack.
  */
 public class NetworkStackUtils {
+    static {
+        System.loadLibrary("networkstackutilsjni");
+    }
 
     /**
      * @return True if the array is null or 0-length.
@@ -98,4 +102,39 @@ public class NetworkStackUtils {
         String value = DeviceConfig.getProperty(namespace, name);
         return value != null ? value : defaultValue;
     }
+
+    /**
+     * Attaches a socket filter that accepts DHCP packets to the given socket.
+     */
+    public static native void attachDhcpFilter(FileDescriptor fd) throws SocketException;
+
+    /**
+     * Attaches a socket filter that accepts ICMPv6 router advertisements to the given socket.
+     * @param fd the socket's {@link FileDescriptor}.
+     * @param packetType the hardware address type, one of ARPHRD_*.
+     */
+    public static native void attachRaFilter(FileDescriptor fd, int packetType)
+            throws SocketException;
+
+    /**
+     * Attaches a socket filter that accepts L2-L4 signaling traffic required for IP connectivity.
+     *
+     * This includes: all ARP, ICMPv6 RS/RA/NS/NA messages, and DHCPv4 exchanges.
+     *
+     * @param fd the socket's {@link FileDescriptor}.
+     * @param packetType the hardware address type, one of ARPHRD_*.
+     */
+    public static native void attachControlPacketFilter(FileDescriptor fd, int packetType)
+            throws SocketException;
+
+    /**
+     * Add an entry into the ARP cache.
+     */
+    public static void addArpEntry(Inet4Address ipv4Addr, android.net.MacAddress ethAddr,
+            String ifname, FileDescriptor fd) throws IOException {
+        addArpEntry(ethAddr.toByteArray(), ipv4Addr.getAddress(), ifname, fd);
+    }
+
+    private static native void addArpEntry(byte[] ethAddr, byte[] netAddr, String ifname,
+            FileDescriptor fd) throws IOException;
 }