Add TcpKeepalivePacketData to SystemApi

This is consistent with NattKeepalivePacketData, which is also a
subclass of KeepalivePacketData.

TcpKeepalivePacketData is already used by the wifi module, but
statically linked.

Bug: 172789687
Test: m
Change-Id: I6aee1ae205987521bea4a3838bbece279ffa0e37

3 files changed, 129 insertions, 273 deletions

diff --git a/services/net/java/android/net/TcpKeepalivePacketData.java b/services/net/java/android/net/TcpKeepalivePacketData.java
deleted file mode 100644
index 4875c7cc4263..000000000000
--- a/services/net/java/android/net/TcpKeepalivePacketData.java
+++ /dev/null
@@ -1,268 +0,0 @@
-/*
- * Copyright (C) 2019 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;
-
-import static android.net.SocketKeepalive.ERROR_INVALID_IP_ADDRESS;
-
-import android.annotation.NonNull;
-import android.annotation.Nullable;
-import android.os.Parcel;
-import android.os.Parcelable;
-import android.system.OsConstants;
-
-import com.android.net.module.util.IpUtils;
-
-import java.net.InetAddress;
-import java.net.UnknownHostException;
-import java.nio.ByteBuffer;
-import java.nio.ByteOrder;
-import java.util.Objects;
-
-/**
- * Represents the actual tcp keep alive packets which will be used for hardware offload.
- * @hide
- */
-public class TcpKeepalivePacketData extends KeepalivePacketData implements Parcelable {
-    private static final String TAG = "TcpKeepalivePacketData";
-
-    /** TCP sequence number. */
-    public final int tcpSeq;
-
-    /** TCP ACK number. */
-    public final int tcpAck;
-
-    /** TCP RCV window. */
-    public final int tcpWnd;
-
-    /** TCP RCV window scale. */
-    public final int tcpWndScale;
-
-    /** IP TOS. */
-    public final int ipTos;
-
-    /** IP TTL. */
-    public final int ipTtl;
-
-    private static final int IPV4_HEADER_LENGTH = 20;
-    private static final int IPV6_HEADER_LENGTH = 40;
-    private static final int TCP_HEADER_LENGTH = 20;
-
-    // This should only be constructed via static factory methods, such as
-    // tcpKeepalivePacket.
-    private TcpKeepalivePacketData(final TcpKeepalivePacketDataParcelable tcpDetails,
-            final byte[] data) throws InvalidPacketException, UnknownHostException {
-        super(InetAddress.getByAddress(tcpDetails.srcAddress), tcpDetails.srcPort,
-                InetAddress.getByAddress(tcpDetails.dstAddress), tcpDetails.dstPort, data);
-        tcpSeq = tcpDetails.seq;
-        tcpAck = tcpDetails.ack;
-        // In the packet, the window is shifted right by the window scale.
-        tcpWnd = tcpDetails.rcvWnd;
-        tcpWndScale = tcpDetails.rcvWndScale;
-        ipTos = tcpDetails.tos;
-        ipTtl = tcpDetails.ttl;
-    }
-
-    private TcpKeepalivePacketData(final InetAddress srcAddress, int srcPort,
-            final InetAddress dstAddress, int dstPort, final byte[] data, int tcpSeq,
-            int tcpAck, int tcpWnd, int tcpWndScale, int ipTos, int ipTtl)
-            throws InvalidPacketException {
-        super(srcAddress, srcPort, dstAddress, dstPort, data);
-        this.tcpSeq = tcpSeq;
-        this.tcpAck = tcpAck;
-        this.tcpWnd = tcpWnd;
-        this.tcpWndScale = tcpWndScale;
-        this.ipTos = ipTos;
-        this.ipTtl = ipTtl;
-    }
-
-    /**
-     * Factory method to create tcp keepalive packet structure.
-     */
-    public static TcpKeepalivePacketData tcpKeepalivePacket(
-            TcpKeepalivePacketDataParcelable tcpDetails) throws InvalidPacketException {
-        final byte[] packet;
-        try {
-            if ((tcpDetails.srcAddress != null) && (tcpDetails.dstAddress != null)
-                    && (tcpDetails.srcAddress.length == 4 /* V4 IP length */)
-                    && (tcpDetails.dstAddress.length == 4 /* V4 IP length */)) {
-                packet = buildV4Packet(tcpDetails);
-            } else {
-                // TODO: support ipv6
-                throw new InvalidPacketException(ERROR_INVALID_IP_ADDRESS);
-            }
-            return new TcpKeepalivePacketData(tcpDetails, packet);
-        } catch (UnknownHostException e) {
-            throw new InvalidPacketException(ERROR_INVALID_IP_ADDRESS);
-        }
-
-    }
-
-    /**
-     * Build ipv4 tcp keepalive packet, not including the link-layer header.
-     */
-    // TODO : if this code is ever moved to the network stack, factorize constants with the ones
-    // over there.
-    private static byte[] buildV4Packet(TcpKeepalivePacketDataParcelable tcpDetails) {
-        final int length = IPV4_HEADER_LENGTH + TCP_HEADER_LENGTH;
-        ByteBuffer buf = ByteBuffer.allocate(length);
-        buf.order(ByteOrder.BIG_ENDIAN);
-        buf.put((byte) 0x45);                       // IP version and IHL
-        buf.put((byte) tcpDetails.tos);             // TOS
-        buf.putShort((short) length);
-        buf.putInt(0x00004000);                     // ID, flags=DF, offset
-        buf.put((byte) tcpDetails.ttl);             // TTL
-        buf.put((byte) OsConstants.IPPROTO_TCP);
-        final int ipChecksumOffset = buf.position();
-        buf.putShort((short) 0);                    // IP checksum
-        buf.put(tcpDetails.srcAddress);
-        buf.put(tcpDetails.dstAddress);
-        buf.putShort((short) tcpDetails.srcPort);
-        buf.putShort((short) tcpDetails.dstPort);
-        buf.putInt(tcpDetails.seq);                 // Sequence Number
-        buf.putInt(tcpDetails.ack);                 // ACK
-        buf.putShort((short) 0x5010);               // TCP length=5, flags=ACK
-        buf.putShort((short) (tcpDetails.rcvWnd >> tcpDetails.rcvWndScale));   // Window size
-        final int tcpChecksumOffset = buf.position();
-        buf.putShort((short) 0);                    // TCP checksum
-        // URG is not set therefore the urgent pointer is zero.
-        buf.putShort((short) 0);                    // Urgent pointer
-
-        buf.putShort(ipChecksumOffset, IpUtils.ipChecksum(buf, 0));
-        buf.putShort(tcpChecksumOffset, IpUtils.tcpChecksum(
-                buf, 0, IPV4_HEADER_LENGTH, TCP_HEADER_LENGTH));
-
-        return buf.array();
-    }
-
-    // TODO: add buildV6Packet.
-
-    @Override
-    public boolean equals(@Nullable final Object o) {
-        if (!(o instanceof TcpKeepalivePacketData)) return false;
-        final TcpKeepalivePacketData other = (TcpKeepalivePacketData) o;
-        final InetAddress srcAddress = getSrcAddress();
-        final InetAddress dstAddress = getDstAddress();
-        return srcAddress.equals(other.getSrcAddress())
-                && dstAddress.equals(other.getDstAddress())
-                && getSrcPort() == other.getSrcPort()
-                && getDstPort() == other.getDstPort()
-                && this.tcpAck == other.tcpAck
-                && this.tcpSeq == other.tcpSeq
-                && this.tcpWnd == other.tcpWnd
-                && this.tcpWndScale == other.tcpWndScale
-                && this.ipTos == other.ipTos
-                && this.ipTtl == other.ipTtl;
-    }
-
-    @Override
-    public int hashCode() {
-        return Objects.hash(getSrcAddress(), getDstAddress(), getSrcPort(), getDstPort(),
-                tcpAck, tcpSeq, tcpWnd, tcpWndScale, ipTos, ipTtl);
-    }
-
-    /**
-     * Parcelable Implementation.
-     * Note that this object implements parcelable (and needs to keep doing this as it inherits
-     * from a class that does), but should usually be parceled as a stable parcelable using
-     * the toStableParcelable() and fromStableParcelable() methods.
-     */
-    public int describeContents() {
-        return 0;
-    }
-
-    /** Write to parcel. */
-    public void writeToParcel(Parcel out, int flags) {
-        out.writeString(getSrcAddress().getHostAddress());
-        out.writeString(getDstAddress().getHostAddress());
-        out.writeInt(getSrcPort());
-        out.writeInt(getDstPort());
-        out.writeByteArray(getPacket());
-        out.writeInt(tcpSeq);
-        out.writeInt(tcpAck);
-        out.writeInt(tcpWnd);
-        out.writeInt(tcpWndScale);
-        out.writeInt(ipTos);
-        out.writeInt(ipTtl);
-    }
-
-    private static TcpKeepalivePacketData readFromParcel(Parcel in) throws InvalidPacketException {
-        InetAddress srcAddress = InetAddresses.parseNumericAddress(in.readString());
-        InetAddress dstAddress = InetAddresses.parseNumericAddress(in.readString());
-        int srcPort = in.readInt();
-        int dstPort = in.readInt();
-        byte[] packet = in.createByteArray();
-        int tcpSeq = in.readInt();
-        int tcpAck = in.readInt();
-        int tcpWnd = in.readInt();
-        int tcpWndScale = in.readInt();
-        int ipTos = in.readInt();
-        int ipTtl = in.readInt();
-        return new TcpKeepalivePacketData(srcAddress, srcPort, dstAddress, dstPort, packet, tcpSeq,
-                tcpAck, tcpWnd, tcpWndScale, ipTos, ipTtl);
-    }
-
-    /** Parcelable Creator. */
-    public static final @NonNull Parcelable.Creator<TcpKeepalivePacketData> CREATOR =
-            new Parcelable.Creator<TcpKeepalivePacketData>() {
-                public TcpKeepalivePacketData createFromParcel(Parcel in) {
-                    try {
-                        return readFromParcel(in);
-                    } catch (InvalidPacketException e) {
-                        throw new IllegalArgumentException(
-                                "Invalid NAT-T keepalive data: " + e.getError());
-                    }
-                }
-
-                public TcpKeepalivePacketData[] newArray(int size) {
-                    return new TcpKeepalivePacketData[size];
-                }
-            };
-
-    /**
-     * Convert this TcpKeepalivePacketData to a TcpKeepalivePacketDataParcelable.
-     */
-    @NonNull
-    public TcpKeepalivePacketDataParcelable toStableParcelable() {
-        final TcpKeepalivePacketDataParcelable parcel = new TcpKeepalivePacketDataParcelable();
-        final InetAddress srcAddress = getSrcAddress();
-        final InetAddress dstAddress = getDstAddress();
-        parcel.srcAddress = srcAddress.getAddress();
-        parcel.srcPort = getSrcPort();
-        parcel.dstAddress = dstAddress.getAddress();
-        parcel.dstPort = getDstPort();
-        parcel.seq = tcpSeq;
-        parcel.ack = tcpAck;
-        parcel.rcvWnd = tcpWnd;
-        parcel.rcvWndScale = tcpWndScale;
-        parcel.tos = ipTos;
-        parcel.ttl = ipTtl;
-        return parcel;
-    }
-
-    @Override
-    public String toString() {
-        return "saddr: " + getSrcAddress()
-                + " daddr: " + getDstAddress()
-                + " sport: " + getSrcPort()
-                + " dport: " + getDstPort()
-                + " seq: " + tcpSeq
-                + " ack: " + tcpAck
-                + " wnd: " + tcpWnd
-                + " wndScale: " + tcpWndScale
-                + " tos: " + ipTos
-                + " ttl: " + ipTtl;
-    }
-}
diff --git a/services/net/java/android/net/ip/IpClientManager.java b/services/net/java/android/net/ip/IpClientManager.java
index db464e732e91..274b6dc1769b 100644
--- a/services/net/java/android/net/ip/IpClientManager.java
+++ b/services/net/java/android/net/ip/IpClientManager.java
@@ -21,6 +21,7 @@ import android.annotation.NonNull;
 import android.net.NattKeepalivePacketData;
 import android.net.ProxyInfo;
 import android.net.TcpKeepalivePacketData;
+import android.net.TcpKeepalivePacketDataParcelable;
 import android.net.shared.Layer2Information;
 import android.net.shared.ProvisioningConfiguration;
 import android.net.util.KeepalivePacketDataUtil;
@@ -215,9 +216,20 @@ public class IpClientManager {
      * Add a TCP keepalive packet filter before setting up keepalive offload.
      */
     public boolean addKeepalivePacketFilter(int slot, TcpKeepalivePacketData pkt) {
+        return addKeepalivePacketFilter(slot, KeepalivePacketDataUtil.toStableParcelable(pkt));
+    }
+
+    /**
+     * Add a TCP keepalive packet filter before setting up keepalive offload.
+     * @deprecated This method is for use on pre-S platforms where TcpKeepalivePacketData is not
+     *             system API. On newer platforms use
+     *             addKeepalivePacketFilter(int, TcpKeepalivePacketData) instead.
+     */
+    @Deprecated
+    public boolean addKeepalivePacketFilter(int slot, TcpKeepalivePacketDataParcelable pkt) {
         final long token = Binder.clearCallingIdentity();
         try {
-            mIpClient.addKeepalivePacketFilter(slot, pkt.toStableParcelable());
+            mIpClient.addKeepalivePacketFilter(slot, pkt);
             return true;
         } catch (RemoteException e) {
             log("Error adding Keepalive Packet Filter ", e);
diff --git a/services/net/java/android/net/util/KeepalivePacketDataUtil.java b/services/net/java/android/net/util/KeepalivePacketDataUtil.java
index 4466ea0abe0e..f06070b6870d 100644
--- a/services/net/java/android/net/util/KeepalivePacketDataUtil.java
+++ b/services/net/java/android/net/util/KeepalivePacketDataUtil.java
@@ -16,20 +16,41 @@
 
 package android.net.util;
 
+import static android.net.SocketKeepalive.ERROR_INVALID_IP_ADDRESS;
+
 import android.annotation.NonNull;
+import android.net.InvalidPacketException;
 import android.net.NattKeepalivePacketData;
 import android.net.NattKeepalivePacketDataParcelable;
+import android.net.TcpKeepalivePacketData;
+import android.net.TcpKeepalivePacketDataParcelable;
+import android.system.OsConstants;
+
+import com.android.net.module.util.IpUtils;
 
 import java.net.InetAddress;
+import java.net.UnknownHostException;
+import java.nio.ByteBuffer;
+import java.nio.ByteOrder;
 
-/** @hide */
+/**
+ * Utility class to convert to/from keepalive data parcelables.
+ *
+ * TODO: move to networkstack-client library when it is moved to frameworks/libs/net.
+ * This class cannot go into other shared libraries as it depends on NetworkStack AIDLs.
+ * @hide
+ */
 public final class KeepalivePacketDataUtil {
-     /**
-     * Convert this NattKeepalivePacketData to a NattKeepalivePacketDataParcelable.
+    private static final int IPV4_HEADER_LENGTH = 20;
+    private static final int IPV6_HEADER_LENGTH = 40;
+    private static final int TCP_HEADER_LENGTH = 20;
+
+    /**
+     * Convert a NattKeepalivePacketData to a NattKeepalivePacketDataParcelable.
      */
     @NonNull
     public static NattKeepalivePacketDataParcelable toStableParcelable(
-            NattKeepalivePacketData pkt) {
+            @NonNull NattKeepalivePacketData pkt) {
         final NattKeepalivePacketDataParcelable parcel = new NattKeepalivePacketDataParcelable();
         final InetAddress srcAddress = pkt.getSrcAddress();
         final InetAddress dstAddress = pkt.getDstAddress();
@@ -39,4 +60,95 @@ public final class KeepalivePacketDataUtil {
         parcel.dstPort = pkt.getDstPort();
         return parcel;
     }
+
+    /**
+     * Convert a TcpKeepalivePacketData to a TcpKeepalivePacketDataParcelable.
+     */
+    @NonNull
+    public static TcpKeepalivePacketDataParcelable toStableParcelable(
+            @NonNull TcpKeepalivePacketData pkt) {
+        final TcpKeepalivePacketDataParcelable parcel = new TcpKeepalivePacketDataParcelable();
+        final InetAddress srcAddress = pkt.getSrcAddress();
+        final InetAddress dstAddress = pkt.getDstAddress();
+        parcel.srcAddress = srcAddress.getAddress();
+        parcel.srcPort = pkt.getSrcPort();
+        parcel.dstAddress = dstAddress.getAddress();
+        parcel.dstPort = pkt.getDstPort();
+        parcel.seq = pkt.tcpSeq;
+        parcel.ack = pkt.tcpAck;
+        parcel.rcvWnd = pkt.tcpWindow;
+        parcel.rcvWndScale = pkt.tcpWindowScale;
+        parcel.tos = pkt.ipTos;
+        parcel.ttl = pkt.ipTtl;
+        return parcel;
+    }
+
+    /**
+     * Factory method to create tcp keepalive packet structure.
+     * @hide
+     */
+    public static TcpKeepalivePacketData fromStableParcelable(
+            TcpKeepalivePacketDataParcelable tcpDetails) throws InvalidPacketException {
+        final byte[] packet;
+        try {
+            if ((tcpDetails.srcAddress != null) && (tcpDetails.dstAddress != null)
+                    && (tcpDetails.srcAddress.length == 4 /* V4 IP length */)
+                    && (tcpDetails.dstAddress.length == 4 /* V4 IP length */)) {
+                packet = buildV4Packet(tcpDetails);
+            } else {
+                // TODO: support ipv6
+                throw new InvalidPacketException(ERROR_INVALID_IP_ADDRESS);
+            }
+            return new TcpKeepalivePacketData(
+                    InetAddress.getByAddress(tcpDetails.srcAddress),
+                    tcpDetails.srcPort,
+                    InetAddress.getByAddress(tcpDetails.dstAddress),
+                    tcpDetails.dstPort,
+                    packet,
+                    tcpDetails.seq, tcpDetails.ack, tcpDetails.rcvWnd, tcpDetails.rcvWndScale,
+                    tcpDetails.tos, tcpDetails.ttl);
+        } catch (UnknownHostException e) {
+            throw new InvalidPacketException(ERROR_INVALID_IP_ADDRESS);
+        }
+
+    }
+
+    /**
+     * Build ipv4 tcp keepalive packet, not including the link-layer header.
+     */
+    // TODO : if this code is ever moved to the network stack, factorize constants with the ones
+    // over there.
+    private static byte[] buildV4Packet(TcpKeepalivePacketDataParcelable tcpDetails) {
+        final int length = IPV4_HEADER_LENGTH + TCP_HEADER_LENGTH;
+        ByteBuffer buf = ByteBuffer.allocate(length);
+        buf.order(ByteOrder.BIG_ENDIAN);
+        buf.put((byte) 0x45);                       // IP version and IHL
+        buf.put((byte) tcpDetails.tos);             // TOS
+        buf.putShort((short) length);
+        buf.putInt(0x00004000);                     // ID, flags=DF, offset
+        buf.put((byte) tcpDetails.ttl);             // TTL
+        buf.put((byte) OsConstants.IPPROTO_TCP);
+        final int ipChecksumOffset = buf.position();
+        buf.putShort((short) 0);                    // IP checksum
+        buf.put(tcpDetails.srcAddress);
+        buf.put(tcpDetails.dstAddress);
+        buf.putShort((short) tcpDetails.srcPort);
+        buf.putShort((short) tcpDetails.dstPort);
+        buf.putInt(tcpDetails.seq);                 // Sequence Number
+        buf.putInt(tcpDetails.ack);                 // ACK
+        buf.putShort((short) 0x5010);               // TCP length=5, flags=ACK
+        buf.putShort((short) (tcpDetails.rcvWnd >> tcpDetails.rcvWndScale));   // Window size
+        final int tcpChecksumOffset = buf.position();
+        buf.putShort((short) 0);                    // TCP checksum
+        // URG is not set therefore the urgent pointer is zero.
+        buf.putShort((short) 0);                    // Urgent pointer
+
+        buf.putShort(ipChecksumOffset, com.android.net.module.util.IpUtils.ipChecksum(buf, 0));
+        buf.putShort(tcpChecksumOffset, IpUtils.tcpChecksum(
+                buf, 0, IPV4_HEADER_LENGTH, TCP_HEADER_LENGTH));
+
+        return buf.array();
+    }
+
+    // TODO: add buildV6Packet.
 }