core/java/android/net/IpPrefix.java - platform/frameworks/base - Git at Google

 /*
  * Copyright (C) 2014 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 android.os.Parcel;
 import android.os.Parcelable;
 import android.util.Pair;

 import java.net.InetAddress;
 import java.net.UnknownHostException;
 import java.util.Arrays;

 /**
  * This class represents an IP prefix, i.e., a contiguous block of IP addresses aligned on a
  * power of two boundary (also known as an "IP subnet"). A prefix is specified by two pieces of
  * information:
  *
  * <ul>
  * <li>A starting IP address (IPv4 or IPv6). This is the first IP address of the prefix.
  * <li>A prefix length. This specifies the length of the prefix by specifing the number of bits
  *     in the IP address, starting from the most significant bit in network byte order, that
  *     are constant for all addresses in the prefix.
  * </ul>
  *
  * For example, the prefix <code>192.0.2.0/24</code> covers the 256 IPv4 addresses from
  * <code>192.0.2.0</code> to <code>192.0.2.255</code>, inclusive, and the prefix
  * <code>2001:db8:1:2</code>  covers the 2^64 IPv6 addresses from <code>2001:db8:1:2::</code> to
  * <code>2001:db8:1:2:ffff:ffff:ffff:ffff</code>, inclusive.
  *
  * Objects of this class are immutable.
  */
 public final class IpPrefix implements Parcelable {
     private final byte[] address;  // network byte order
     private final int prefixLength;

     private void checkAndMaskAddressAndPrefixLength() {
         if (address.length != 4 && address.length != 16) {
             throw new IllegalArgumentException(
                     "IpPrefix has " + address.length + " bytes which is neither 4 nor 16");
         }
         NetworkUtils.maskRawAddress(address, prefixLength);
     }

     /**
      * Constructs a new {@code IpPrefix} from a byte array containing an IPv4 or IPv6 address in
      * network byte order and a prefix length. Silently truncates the address to the prefix length,
      * so for example {@code 192.0.2.1/24} is silently converted to {@code 192.0.2.0/24}.
      *
      * @param address the IP address. Must be non-null and exactly 4 or 16 bytes long.
      * @param prefixLength the prefix length. Must be &gt;= 0 and &lt;= (32 or 128) (IPv4 or IPv6).
      *
      * @hide
      */
     public IpPrefix(byte[] address, int prefixLength) {
         this.address = address.clone();
         this.prefixLength = prefixLength;
         checkAndMaskAddressAndPrefixLength();
     }

     /**
      * Constructs a new {@code IpPrefix} from an IPv4 or IPv6 address and a prefix length. Silently
      * truncates the address to the prefix length, so for example {@code 192.0.2.1/24} is silently
      * converted to {@code 192.0.2.0/24}.
      *
      * @param address the IP address. Must be non-null.
      * @param prefixLength the prefix length. Must be &gt;= 0 and &lt;= (32 or 128) (IPv4 or IPv6).
      * @hide
      */
     public IpPrefix(InetAddress address, int prefixLength) {
         // We don't reuse the (byte[], int) constructor because it calls clone() on the byte array,
         // which is unnecessary because getAddress() already returns a clone.
         this.address = address.getAddress();
         this.prefixLength = prefixLength;
         checkAndMaskAddressAndPrefixLength();
     }

     /**
      * Constructs a new IpPrefix from a string such as "192.0.2.1/24" or "2001:db8::1/64".
      * Silently truncates the address to the prefix length, so for example {@code 192.0.2.1/24}
      * is silently converted to {@code 192.0.2.0/24}.
      *
      * @param prefix the prefix to parse
      *
      * @hide
      */
     public IpPrefix(String prefix) {
         // We don't reuse the (InetAddress, int) constructor because "error: call to this must be
         // first statement in constructor". We could factor out setting the member variables to an
         // init() method, but if we did, then we'd have to make the members non-final, or "error:
         // cannot assign a value to final variable address". So we just duplicate the code here.
         Pair<InetAddress, Integer> ipAndMask = NetworkUtils.parseIpAndMask(prefix);
         this.address = ipAndMask.first.getAddress();
         this.prefixLength = ipAndMask.second;
         checkAndMaskAddressAndPrefixLength();
     }

     /**
      * Compares this {@code IpPrefix} object against the specified object in {@code obj}. Two
      * objects are equal if they have the same startAddress and prefixLength.
      *
      * @param obj the object to be tested for equality.
      * @return {@code true} if both objects are equal, {@code false} otherwise.
      */
     @Override
     public boolean equals(Object obj) {
         if (!(obj instanceof IpPrefix)) {
             return false;
         }
         IpPrefix that = (IpPrefix) obj;
         return Arrays.equals(this.address, that.address) && this.prefixLength == that.prefixLength;
     }

     /**
      * Gets the hashcode of the represented IP prefix.
      *
      * @return the appropriate hashcode value.
      */
     @Override
     public int hashCode() {
         return Arrays.hashCode(address) + 11 * prefixLength;
     }

     /**
      * Returns a copy of the first IP address in the prefix. Modifying the returned object does not
      * change this object's contents.
      *
      * @return the address in the form of a byte array.
      */
     public InetAddress getAddress() {
         try {
             return InetAddress.getByAddress(address);
         } catch (UnknownHostException e) {
             // Cannot happen. InetAddress.getByAddress can only throw an exception if the byte
             // array is the wrong length, but we check that in the constructor.
             return null;
         }
     }

     /**
      * Returns a copy of the IP address bytes in network order (the highest order byte is the zeroth
      * element). Modifying the returned array does not change this object's contents.
      *
      * @return the address in the form of a byte array.
      */
     public byte[] getRawAddress() {
         return address.clone();
     }

     /**
      * Returns the prefix length of this {@code IpPrefix}.
      *
      * @return the prefix length.
      */
     public int getPrefixLength() {
         return prefixLength;
     }

     /**
      * Determines whether the prefix contains the specified address.
      *
      * @param address An {@link InetAddress} to test.
      * @return {@code true} if the prefix covers the given address.
      */
     public boolean contains(InetAddress address) {
         byte[] addrBytes = (address == null) ? null : address.getAddress();
         if (addrBytes == null || addrBytes.length != this.address.length) {
             return false;
         }
         NetworkUtils.maskRawAddress(addrBytes, prefixLength);
         return Arrays.equals(this.address, addrBytes);
     }

     /**
      * Returns a string representation of this {@code IpPrefix}.
      *
      * @return a string such as {@code "192.0.2.0/24"} or {@code "2001:db8:1:2::/64"}.
      */
     public String toString() {
         try {
             return InetAddress.getByAddress(address).getHostAddress() + "/" + prefixLength;
         } catch(UnknownHostException e) {
             // Cosmic rays?
             throw new IllegalStateException("IpPrefix with invalid address! Shouldn't happen.", e);
         }
     }

     /**
      * Implement the Parcelable interface.
      */
     public int describeContents() {
         return 0;
     }

     /**
      * Implement the Parcelable interface.
      */
     public void writeToParcel(Parcel dest, int flags) {
         dest.writeByteArray(address);
         dest.writeInt(prefixLength);
     }

     /**
      * Implement the Parcelable interface.
      */
     public static final Creator<IpPrefix> CREATOR =
             new Creator<IpPrefix>() {
                 public IpPrefix createFromParcel(Parcel in) {
                     byte[] address = in.createByteArray();
                     int prefixLength = in.readInt();
                     return new IpPrefix(address, prefixLength);
                 }

                 public IpPrefix[] newArray(int size) {
                     return new IpPrefix[size];
                 }
             };
 }
	/*
	* Copyright (C) 2014 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 android.os.Parcel;
	import android.os.Parcelable;
	import android.util.Pair;

	import java.net.InetAddress;
	import java.net.UnknownHostException;
	import java.util.Arrays;

	/**
	* This class represents an IP prefix, i.e., a contiguous block of IP addresses aligned on a
	* power of two boundary (also known as an "IP subnet"). A prefix is specified by two pieces of
	* information:
	*
	* <ul>
	* <li>A starting IP address (IPv4 or IPv6). This is the first IP address of the prefix.
	* <li>A prefix length. This specifies the length of the prefix by specifing the number of bits
	* in the IP address, starting from the most significant bit in network byte order, that
	* are constant for all addresses in the prefix.
	* </ul>
	*
	* For example, the prefix <code>192.0.2.0/24</code> covers the 256 IPv4 addresses from
	* <code>192.0.2.0</code> to <code>192.0.2.255</code>, inclusive, and the prefix
	* <code>2001:db8:1:2</code> covers the 2^64 IPv6 addresses from <code>2001:db8:1:2::</code> to
	* <code>2001:db8:1:2:ffff:ffff:ffff:ffff</code>, inclusive.
	*
	* Objects of this class are immutable.
	*/
	public final class IpPrefix implements Parcelable {
	private final byte[] address; // network byte order
	private final int prefixLength;

	private void checkAndMaskAddressAndPrefixLength() {
	if (address.length != 4 && address.length != 16) {
	throw new IllegalArgumentException(
	"IpPrefix has " + address.length + " bytes which is neither 4 nor 16");
	}
	NetworkUtils.maskRawAddress(address, prefixLength);
	}

	/**
	* Constructs a new {@code IpPrefix} from a byte array containing an IPv4 or IPv6 address in
	* network byte order and a prefix length. Silently truncates the address to the prefix length,
	* so for example {@code 192.0.2.1/24} is silently converted to {@code 192.0.2.0/24}.
	*
	* @param address the IP address. Must be non-null and exactly 4 or 16 bytes long.
	* @param prefixLength the prefix length. Must be >= 0 and <= (32 or 128) (IPv4 or IPv6).
	*
	* @hide
	*/
	public IpPrefix(byte[] address, int prefixLength) {
	this.address = address.clone();
	this.prefixLength = prefixLength;
	checkAndMaskAddressAndPrefixLength();
	}

	/**
	* Constructs a new {@code IpPrefix} from an IPv4 or IPv6 address and a prefix length. Silently
	* truncates the address to the prefix length, so for example {@code 192.0.2.1/24} is silently
	* converted to {@code 192.0.2.0/24}.
	*
	* @param address the IP address. Must be non-null.
	* @param prefixLength the prefix length. Must be >= 0 and <= (32 or 128) (IPv4 or IPv6).
	* @hide
	*/
	public IpPrefix(InetAddress address, int prefixLength) {
	// We don't reuse the (byte[], int) constructor because it calls clone() on the byte array,
	// which is unnecessary because getAddress() already returns a clone.
	this.address = address.getAddress();
	this.prefixLength = prefixLength;
	checkAndMaskAddressAndPrefixLength();
	}

	/**
	* Constructs a new IpPrefix from a string such as "192.0.2.1/24" or "2001:db8::1/64".
	* Silently truncates the address to the prefix length, so for example {@code 192.0.2.1/24}
	* is silently converted to {@code 192.0.2.0/24}.
	*
	* @param prefix the prefix to parse
	*
	* @hide
	*/
	public IpPrefix(String prefix) {
	// We don't reuse the (InetAddress, int) constructor because "error: call to this must be
	// first statement in constructor". We could factor out setting the member variables to an
	// init() method, but if we did, then we'd have to make the members non-final, or "error:
	// cannot assign a value to final variable address". So we just duplicate the code here.
	Pair<InetAddress, Integer> ipAndMask = NetworkUtils.parseIpAndMask(prefix);
	this.address = ipAndMask.first.getAddress();
	this.prefixLength = ipAndMask.second;
	checkAndMaskAddressAndPrefixLength();
	}

	/**
	* Compares this {@code IpPrefix} object against the specified object in {@code obj}. Two
	* objects are equal if they have the same startAddress and prefixLength.
	*
	* @param obj the object to be tested for equality.
	* @return {@code true} if both objects are equal, {@code false} otherwise.
	*/
	@Override
	public boolean equals(Object obj) {
	if (!(obj instanceof IpPrefix)) {
	return false;
	}
	IpPrefix that = (IpPrefix) obj;
	return Arrays.equals(this.address, that.address) && this.prefixLength == that.prefixLength;
	}

	/**
	* Gets the hashcode of the represented IP prefix.
	*
	* @return the appropriate hashcode value.
	*/
	@Override
	public int hashCode() {
	return Arrays.hashCode(address) + 11 * prefixLength;
	}

	/**
	* Returns a copy of the first IP address in the prefix. Modifying the returned object does not
	* change this object's contents.
	*
	* @return the address in the form of a byte array.
	*/
	public InetAddress getAddress() {
	try {
	return InetAddress.getByAddress(address);
	} catch (UnknownHostException e) {
	// Cannot happen. InetAddress.getByAddress can only throw an exception if the byte
	// array is the wrong length, but we check that in the constructor.
	return null;
	}
	}

	/**
	* Returns a copy of the IP address bytes in network order (the highest order byte is the zeroth
	* element). Modifying the returned array does not change this object's contents.
	*
	* @return the address in the form of a byte array.
	*/
	public byte[] getRawAddress() {
	return address.clone();
	}

	/**
	* Returns the prefix length of this {@code IpPrefix}.
	*
	* @return the prefix length.
	*/
	public int getPrefixLength() {
	return prefixLength;
	}

	/**
	* Determines whether the prefix contains the specified address.
	*
	* @param address An {@link InetAddress} to test.
	* @return {@code true} if the prefix covers the given address.
	*/
	public boolean contains(InetAddress address) {
	byte[] addrBytes = (address == null) ? null : address.getAddress();
	if (addrBytes == null \|\| addrBytes.length != this.address.length) {
	return false;
	}
	NetworkUtils.maskRawAddress(addrBytes, prefixLength);
	return Arrays.equals(this.address, addrBytes);
	}

	/**
	* Returns a string representation of this {@code IpPrefix}.
	*
	* @return a string such as {@code "192.0.2.0/24"} or {@code "2001:db8:1:2::/64"}.
	*/
	public String toString() {
	try {
	return InetAddress.getByAddress(address).getHostAddress() + "/" + prefixLength;
	} catch(UnknownHostException e) {
	// Cosmic rays?
	throw new IllegalStateException("IpPrefix with invalid address! Shouldn't happen.", e);
	}
	}

	/**
	* Implement the Parcelable interface.
	*/
	public int describeContents() {
	return 0;
	}

	/**
	* Implement the Parcelable interface.
	*/
	public void writeToParcel(Parcel dest, int flags) {
	dest.writeByteArray(address);
	dest.writeInt(prefixLength);
	}

	/**
	* Implement the Parcelable interface.
	*/
	public static final Creator<IpPrefix> CREATOR =
	new Creator<IpPrefix>() {
	public IpPrefix createFromParcel(Parcel in) {
	byte[] address = in.createByteArray();
	int prefixLength = in.readInt();
	return new IpPrefix(address, prefixLength);
	}

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