core/java/android/net/TcpKeepalivePacketData.java - platform/frameworks/base - Gitiles

 /*
  * 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.Inet4Address;
 import java.net.InetAddress;
 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;

     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(TcpSocketInfo tcpDetails, byte[] data)
             throws InvalidPacketException {
         super(tcpDetails.srcAddress, tcpDetails.srcPort, 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;
     }

     /**
      * Factory method to create tcp keepalive packet structure.
      */
     public static TcpKeepalivePacketData tcpKeepalivePacket(
             TcpSocketInfo tcpDetails) throws InvalidPacketException {
         final byte[] packet;
         if ((tcpDetails.srcAddress instanceof Inet4Address)
                 && (tcpDetails.dstAddress instanceof Inet4Address)) {
             packet = buildV4Packet(tcpDetails);
         } else {
             // TODO: support ipv6
             throw new InvalidPacketException(ERROR_INVALID_IP_ADDRESS);
         }

         return new TcpKeepalivePacketData(tcpDetails, packet);
     }

     /**
      * 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(TcpSocketInfo tcpDetails) {
         final int length = IPV4_HEADER_LENGTH + TCP_HEADER_LENGTH;
         ByteBuffer buf = ByteBuffer.allocate(length);
         buf.order(ByteOrder.BIG_ENDIAN);
         // IP version and TOS. TODO : fetch this from getsockopt(SOL_IP, IP_TOS)
         buf.putShort((short) 0x4500);
         buf.putShort((short) length);
         buf.putInt(0x4000);                         // ID, flags=DF, offset
         // TODO : fetch TTL from getsockopt(SOL_IP, IP_TTL)
         buf.put((byte) 64);
         buf.put((byte) OsConstants.IPPROTO_TCP);
         final int ipChecksumOffset = buf.position();
         buf.putShort((short) 0);                    // IP checksum
         buf.put(tcpDetails.srcAddress.getAddress());
         buf.put(tcpDetails.dstAddress.getAddress());
         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 not included
         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.

     /** Represents tcp/ip information. */
     // TODO: Replace TcpSocketInfo with TcpKeepalivePacketDataParcelable.
     public static class TcpSocketInfo {
         public final InetAddress srcAddress;
         public final InetAddress dstAddress;
         public final int srcPort;
         public final int dstPort;
         public final int seq;
         public final int ack;
         public final int rcvWnd;
         public final int rcvWndScale;

         public TcpSocketInfo(InetAddress sAddr, int sPort, InetAddress dAddr,
                 int dPort, int writeSeq, int readSeq, int rWnd, int rWndScale) {
             srcAddress = sAddr;
             dstAddress = dAddr;
             srcPort = sPort;
             dstPort = dPort;
             seq = writeSeq;
             ack = readSeq;
             rcvWnd = rWnd;
             rcvWndScale = rWndScale;
         }
     }

     @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;
     }

     @Override
     public int hashCode() {
         return Objects.hash(srcAddress, dstAddress, srcPort, dstPort, tcpAck, tcpSeq, tcpWnd,
                 tcpWndScale);
     }

     /* 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);
     }

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

     /** Parcelable Creator. */
     public static final @android.annotation.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;
         return parcel;
     }

     @Override
     public String toString() {
         return "saddr: " + srcAddress
                 + " daddr: " + dstAddress
                 + " sport: " + srcPort
                 + " dport: " + dstPort
                 + " seq: " + tcpSeq
                 + " ack: " + tcpAck
                 + " wnd: " + tcpWnd
                 + " wndScale: " + tcpWndScale;
     }
 }
	/*
	* 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.Inet4Address;
	import java.net.InetAddress;
	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;

	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(TcpSocketInfo tcpDetails, byte[] data)
	throws InvalidPacketException {
	super(tcpDetails.srcAddress, tcpDetails.srcPort, 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;
	}

	/**
	* Factory method to create tcp keepalive packet structure.
	*/
	public static TcpKeepalivePacketData tcpKeepalivePacket(
	TcpSocketInfo tcpDetails) throws InvalidPacketException {
	final byte[] packet;
	if ((tcpDetails.srcAddress instanceof Inet4Address)
	&& (tcpDetails.dstAddress instanceof Inet4Address)) {
	packet = buildV4Packet(tcpDetails);
	} else {
	// TODO: support ipv6
	throw new InvalidPacketException(ERROR_INVALID_IP_ADDRESS);
	}

	return new TcpKeepalivePacketData(tcpDetails, packet);
	}

	/**
	* 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(TcpSocketInfo tcpDetails) {
	final int length = IPV4_HEADER_LENGTH + TCP_HEADER_LENGTH;
	ByteBuffer buf = ByteBuffer.allocate(length);
	buf.order(ByteOrder.BIG_ENDIAN);
	// IP version and TOS. TODO : fetch this from getsockopt(SOL_IP, IP_TOS)
	buf.putShort((short) 0x4500);
	buf.putShort((short) length);
	buf.putInt(0x4000); // ID, flags=DF, offset
	// TODO : fetch TTL from getsockopt(SOL_IP, IP_TTL)
	buf.put((byte) 64);
	buf.put((byte) OsConstants.IPPROTO_TCP);
	final int ipChecksumOffset = buf.position();
	buf.putShort((short) 0); // IP checksum
	buf.put(tcpDetails.srcAddress.getAddress());
	buf.put(tcpDetails.dstAddress.getAddress());
	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 not included
	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.

	/** Represents tcp/ip information. */
	// TODO: Replace TcpSocketInfo with TcpKeepalivePacketDataParcelable.
	public static class TcpSocketInfo {
	public final InetAddress srcAddress;
	public final InetAddress dstAddress;
	public final int srcPort;
	public final int dstPort;
	public final int seq;
	public final int ack;
	public final int rcvWnd;
	public final int rcvWndScale;

	public TcpSocketInfo(InetAddress sAddr, int sPort, InetAddress dAddr,
	int dPort, int writeSeq, int readSeq, int rWnd, int rWndScale) {
	srcAddress = sAddr;
	dstAddress = dAddr;
	srcPort = sPort;
	dstPort = dPort;
	seq = writeSeq;
	ack = readSeq;
	rcvWnd = rWnd;
	rcvWndScale = rWndScale;
	}
	}

	@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;
	}

	@Override
	public int hashCode() {
	return Objects.hash(srcAddress, dstAddress, srcPort, dstPort, tcpAck, tcpSeq, tcpWnd,
	tcpWndScale);
	}

	/* 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);
	}

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

	/** Parcelable Creator. */
	public static final @android.annotation.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;
	return parcel;
	}

	@Override
	public String toString() {
	return "saddr: " + srcAddress
	+ " daddr: " + dstAddress
	+ " sport: " + srcPort
	+ " dport: " + dstPort
	+ " seq: " + tcpSeq
	+ " ack: " + tcpAck
	+ " wnd: " + tcpWnd
	+ " wndScale: " + tcpWndScale;
	}
	}