services/net/java/android/net/TcpKeepalivePacketData.java - platform/frameworks/base - Git at Google

 /*
  * 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.net.SocketKeepalive.InvalidPacketException;
 import android.net.util.IpUtils;
 import android.os.Parcel;
 import android.os.Parcelable;
 import android.system.OsConstants;

 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;
     }

     /**
      * 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;
         return this.srcAddress.equals(other.srcAddress)
                 && this.dstAddress.equals(other.dstAddress)
                 && this.srcPort == other.srcPort
                 && this.dstPort == other.dstPort
                 && 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(srcAddress, dstAddress, srcPort, dstPort, 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) {
         super.writeToParcel(out, flags);
         out.writeInt(tcpSeq);
         out.writeInt(tcpAck);
         out.writeInt(tcpWnd);
         out.writeInt(tcpWndScale);
         out.writeInt(ipTos);
         out.writeInt(ipTtl);
     }

     private TcpKeepalivePacketData(Parcel in) {
         super(in);
         tcpSeq = in.readInt();
         tcpAck = in.readInt();
         tcpWnd = in.readInt();
         tcpWndScale = in.readInt();
         ipTos = in.readInt();
         ipTtl = in.readInt();
     }

     /** Parcelable Creator. */
     public static final @NonNull Parcelable.Creator<TcpKeepalivePacketData> CREATOR =
             new Parcelable.Creator<TcpKeepalivePacketData>() {
                 public TcpKeepalivePacketData createFromParcel(Parcel in) {
                     return new TcpKeepalivePacketData(in);
                 }

                 public TcpKeepalivePacketData[] newArray(int size) {
                     return new TcpKeepalivePacketData[size];
                 }
             };

     /**
      * Convert this TcpKeepalivePacketData to a TcpKeepalivePacketDataParcelable.
      */
     @NonNull
     public TcpKeepalivePacketDataParcelable toStableParcelable() {
         final TcpKeepalivePacketDataParcelable parcel = new TcpKeepalivePacketDataParcelable();
         parcel.srcAddress = srcAddress.getAddress();
         parcel.srcPort = srcPort;
         parcel.dstAddress = dstAddress.getAddress();
         parcel.dstPort = dstPort;
         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: " + srcAddress
                 + " daddr: " + dstAddress
                 + " sport: " + srcPort
                 + " dport: " + dstPort
                 + " seq: " + tcpSeq
                 + " ack: " + tcpAck
                 + " wnd: " + tcpWnd
                 + " wndScale: " + tcpWndScale
                 + " tos: " + ipTos
                 + " ttl: " + ipTtl;
     }
 }
	/*
	* 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.net.SocketKeepalive.InvalidPacketException;
	import android.net.util.IpUtils;
	import android.os.Parcel;
	import android.os.Parcelable;
	import android.system.OsConstants;

	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;
	}

	/**
	* 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;
	return this.srcAddress.equals(other.srcAddress)
	&& this.dstAddress.equals(other.dstAddress)
	&& this.srcPort == other.srcPort
	&& this.dstPort == other.dstPort
	&& 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(srcAddress, dstAddress, srcPort, dstPort, 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) {
	super.writeToParcel(out, flags);
	out.writeInt(tcpSeq);
	out.writeInt(tcpAck);
	out.writeInt(tcpWnd);
	out.writeInt(tcpWndScale);
	out.writeInt(ipTos);
	out.writeInt(ipTtl);
	}

	private TcpKeepalivePacketData(Parcel in) {
	super(in);
	tcpSeq = in.readInt();
	tcpAck = in.readInt();
	tcpWnd = in.readInt();
	tcpWndScale = in.readInt();
	ipTos = in.readInt();
	ipTtl = in.readInt();
	}

	/** Parcelable Creator. */
	public static final @NonNull Parcelable.Creator<TcpKeepalivePacketData> CREATOR =
	new Parcelable.Creator<TcpKeepalivePacketData>() {
	public TcpKeepalivePacketData createFromParcel(Parcel in) {
	return new TcpKeepalivePacketData(in);
	}

	public TcpKeepalivePacketData[] newArray(int size) {
	return new TcpKeepalivePacketData[size];
	}
	};

	/**
	* Convert this TcpKeepalivePacketData to a TcpKeepalivePacketDataParcelable.
	*/
	@NonNull
	public TcpKeepalivePacketDataParcelable toStableParcelable() {
	final TcpKeepalivePacketDataParcelable parcel = new TcpKeepalivePacketDataParcelable();
	parcel.srcAddress = srcAddress.getAddress();
	parcel.srcPort = srcPort;
	parcel.dstAddress = dstAddress.getAddress();
	parcel.dstPort = dstPort;
	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: " + srcAddress
	+ " daddr: " + dstAddress
	+ " sport: " + srcPort
	+ " dport: " + dstPort
	+ " seq: " + tcpSeq
	+ " ack: " + tcpAck
	+ " wnd: " + tcpWnd
	+ " wndScale: " + tcpWndScale
	+ " tos: " + ipTos
	+ " ttl: " + ipTtl;
	}
	}