/*
* Copyright (C) 2008 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 java.io.FileDescriptor;
import java.net.InetAddress;
import java.net.Inet4Address;
import java.net.Inet6Address;
import java.net.SocketException;
import java.net.UnknownHostException;
import java.util.Collection;
import java.util.Locale;
import android.os.Parcel;
import android.util.Log;
import android.util.Pair;
/**
* Native methods for managing network interfaces.
*
* {@hide}
*/
public class NetworkUtils {
private static final String TAG = "NetworkUtils";
/**
* Attaches a socket filter that accepts DHCP packets to the given socket.
*/
public native static 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 native static void attachRaFilter(FileDescriptor fd, int packetType) throws SocketException;
/**
* Configures a socket for receiving ICMPv6 router solicitations and sending advertisements.
* @param fd the socket's {@link FileDescriptor}.
* @param ifIndex the interface index.
*/
public native static void setupRaSocket(FileDescriptor fd, int ifIndex) throws SocketException;
/**
* Binds the current process to the network designated by {@code netId}. All sockets created
* in the future (and not explicitly bound via a bound {@link SocketFactory} (see
* {@link Network#getSocketFactory}) will be bound to this network. Note that if this
* {@code Network} ever disconnects all sockets created in this way will cease to work. This
* is by design so an application doesn't accidentally use sockets it thinks are still bound to
* a particular {@code Network}. Passing NETID_UNSET clears the binding.
*/
public native static boolean bindProcessToNetwork(int netId);
/**
* Return the netId last passed to {@link #bindProcessToNetwork}, or NETID_UNSET if
* {@link #unbindProcessToNetwork} has been called since {@link #bindProcessToNetwork}.
*/
public native static int getBoundNetworkForProcess();
/**
* Binds host resolutions performed by this process to the network designated by {@code netId}.
* {@link #bindProcessToNetwork} takes precedence over this setting. Passing NETID_UNSET clears
* the binding.
*
* @deprecated This is strictly for legacy usage to support startUsingNetworkFeature().
*/
public native static boolean bindProcessToNetworkForHostResolution(int netId);
/**
* Explicitly binds {@code socketfd} to the network designated by {@code netId}. This
* overrides any binding via {@link #bindProcessToNetwork}.
* @return 0 on success or negative errno on failure.
*/
public native static int bindSocketToNetwork(int socketfd, int netId);
/**
* Protect {@code fd} from VPN connections. After protecting, data sent through
* this socket will go directly to the underlying network, so its traffic will not be
* forwarded through the VPN.
*/
public static boolean protectFromVpn(FileDescriptor fd) {
return protectFromVpn(fd.getInt$());
}
/**
* Protect {@code socketfd} from VPN connections. After protecting, data sent through
* this socket will go directly to the underlying network, so its traffic will not be
* forwarded through the VPN.
*/
public native static boolean protectFromVpn(int socketfd);
/**
* Determine if {@code uid} can access network designated by {@code netId}.
* @return {@code true} if {@code uid} can access network, {@code false} otherwise.
*/
public native static boolean queryUserAccess(int uid, int netId);
/**
* Convert a IPv4 address from an integer to an InetAddress.
* @param hostAddress an int corresponding to the IPv4 address in network byte order
*/
public static InetAddress intToInetAddress(int hostAddress) {
byte[] addressBytes = { (byte)(0xff & hostAddress),
(byte)(0xff & (hostAddress >> 8)),
(byte)(0xff & (hostAddress >> 16)),
(byte)(0xff & (hostAddress >> 24)) };
try {
return InetAddress.getByAddress(addressBytes);
} catch (UnknownHostException e) {
throw new AssertionError();
}
}
/**
* Convert a IPv4 address from an InetAddress to an integer
* @param inetAddr is an InetAddress corresponding to the IPv4 address
* @return the IP address as an integer in network byte order
*/
public static int inetAddressToInt(Inet4Address inetAddr)
throws IllegalArgumentException {
byte [] addr = inetAddr.getAddress();
return ((addr[3] & 0xff) << 24) | ((addr[2] & 0xff) << 16) |
((addr[1] & 0xff) << 8) | (addr[0] & 0xff);
}
/**
* Convert a network prefix length to an IPv4 netmask integer
* @param prefixLength
* @return the IPv4 netmask as an integer in network byte order
*/
public static int prefixLengthToNetmaskInt(int prefixLength)
throws IllegalArgumentException {
if (prefixLength < 0 || prefixLength > 32) {
throw new IllegalArgumentException("Invalid prefix length (0 <= prefix <= 32)");
}
int value = 0xffffffff << (32 - prefixLength);
return Integer.reverseBytes(value);
}
/**
* Convert a IPv4 netmask integer to a prefix length
* @param netmask as an integer in network byte order
* @return the network prefix length
*/
public static int netmaskIntToPrefixLength(int netmask) {
return Integer.bitCount(netmask);
}
/**
* Convert an IPv4 netmask to a prefix length, checking that the netmask is contiguous.
* @param netmask as a {@code Inet4Address}.
* @return the network prefix length
* @throws IllegalArgumentException the specified netmask was not contiguous.
* @hide
*/
public static int netmaskToPrefixLength(Inet4Address netmask) {
// inetAddressToInt returns an int in *network* byte order.
int i = Integer.reverseBytes(inetAddressToInt(netmask));
int prefixLength = Integer.bitCount(i);
int trailingZeros = Integer.numberOfTrailingZeros(i);
if (trailingZeros != 32 - prefixLength) {
throw new IllegalArgumentException("Non-contiguous netmask: " + Integer.toHexString(i));
}
return prefixLength;
}
/**
* Create an InetAddress from a string where the string must be a standard
* representation of a V4 or V6 address. Avoids doing a DNS lookup on failure
* but it will throw an IllegalArgumentException in that case.
* @param addrString
* @return the InetAddress
* @hide
*/
public static InetAddress numericToInetAddress(String addrString)
throws IllegalArgumentException {
return InetAddress.parseNumericAddress(addrString);
}
/**
* Writes an InetAddress to a parcel. The address may be null. This is likely faster than
* calling writeSerializable.
*/
protected static void parcelInetAddress(Parcel parcel, InetAddress address, int flags) {
byte[] addressArray = (address != null) ? address.getAddress() : null;
parcel.writeByteArray(addressArray);
}
/**
* Reads an InetAddress from a parcel. Returns null if the address that was written was null
* or if the data is invalid.
*/
protected static InetAddress unparcelInetAddress(Parcel in) {
byte[] addressArray = in.createByteArray();
if (addressArray == null) {
return null;
}
try {
return InetAddress.getByAddress(addressArray);
} catch (UnknownHostException e) {
return null;
}
}
/**
* Masks a raw IP address byte array with the specified prefix length.
*/
public static void maskRawAddress(byte[] array, int prefixLength) {
if (prefixLength < 0 || prefixLength > array.length * 8) {
throw new RuntimeException("IP address with " + array.length +
" bytes has invalid prefix length " + prefixLength);
}
int offset = prefixLength / 8;
int remainder = prefixLength % 8;
byte mask = (byte)(0xFF << (8 - remainder));
if (offset < array.length) array[offset] = (byte)(array[offset] & mask);
offset++;
for (; offset < array.length; offset++) {
array[offset] = 0;
}
}
/**
* Get InetAddress masked with prefixLength. Will never return null.
* @param address the IP address to mask with
* @param prefixLength the prefixLength used to mask the IP
*/
public static InetAddress getNetworkPart(InetAddress address, int prefixLength) {
byte[] array = address.getAddress();
maskRawAddress(array, prefixLength);
InetAddress netPart = null;
try {
netPart = InetAddress.getByAddress(array);
} catch (UnknownHostException e) {
throw new RuntimeException("getNetworkPart error - " + e.toString());
}
return netPart;
}
/**
* Returns the implicit netmask of an IPv4 address, as was the custom before 1993.
*/
public static int getImplicitNetmask(Inet4Address address) {
int firstByte = address.getAddress()[0] & 0xff; // Convert to an unsigned value.
if (firstByte < 128) {
return 8;
} else if (firstByte < 192) {
return 16;
} else if (firstByte < 224) {
return 24;
} else {
return 32; // Will likely not end well for other reasons.
}
}
/**
* Utility method to parse strings such as "192.0.2.5/24" or "2001:db8::cafe:d00d/64".
* @hide
*/
public static Pair<InetAddress, Integer> parseIpAndMask(String ipAndMaskString) {
InetAddress address = null;
int prefixLength = -1;
try {
String[] pieces = ipAndMaskString.split("/", 2);
prefixLength = Integer.parseInt(pieces[1]);
address = InetAddress.parseNumericAddress(pieces[0]);
} catch (NullPointerException e) { // Null string.
} catch (ArrayIndexOutOfBoundsException e) { // No prefix length.
} catch (NumberFormatException e) { // Non-numeric prefix.
} catch (IllegalArgumentException e) { // Invalid IP address.
}
if (address == null || prefixLength == -1) {
throw new IllegalArgumentException("Invalid IP address and mask " + ipAndMaskString);
}
return new Pair<InetAddress, Integer>(address, prefixLength);
}
/**
* Check if IP address type is consistent between two InetAddress.
* @return true if both are the same type. False otherwise.
*/
public static boolean addressTypeMatches(InetAddress left, InetAddress right) {
return (((left instanceof Inet4Address) && (right instanceof Inet4Address)) ||
((left instanceof Inet6Address) && (right instanceof Inet6Address)));
}
/**
* Convert a 32 char hex string into a Inet6Address.
* throws a runtime exception if the string isn't 32 chars, isn't hex or can't be
* made into an Inet6Address
* @param addrHexString a 32 character hex string representing an IPv6 addr
* @return addr an InetAddress representation for the string
*/
public static InetAddress hexToInet6Address(String addrHexString)
throws IllegalArgumentException {
try {
return numericToInetAddress(String.format(Locale.US, "%s:%s:%s:%s:%s:%s:%s:%s",
addrHexString.substring(0,4), addrHexString.substring(4,8),
addrHexString.substring(8,12), addrHexString.substring(12,16),
addrHexString.substring(16,20), addrHexString.substring(20,24),
addrHexString.substring(24,28), addrHexString.substring(28,32)));
} catch (Exception e) {
Log.e("NetworkUtils", "error in hexToInet6Address(" + addrHexString + "): " + e);
throw new IllegalArgumentException(e);
}
}
/**
* Create a string array of host addresses from a collection of InetAddresses
* @param addrs a Collection of InetAddresses
* @return an array of Strings containing their host addresses
*/
public static String[] makeStrings(Collection<InetAddress> addrs) {
String[] result = new String[addrs.size()];
int i = 0;
for (InetAddress addr : addrs) {
result[i++] = addr.getHostAddress();
}
return result;
}
/**
* Trim leading zeros from IPv4 address strings
* Our base libraries will interpret that as octel..
* Must leave non v4 addresses and host names alone.
* For example, 192.168.000.010 -> 192.168.0.10
* TODO - fix base libraries and remove this function
* @param addr a string representing an ip addr
* @return a string propertly trimmed
*/
public static String trimV4AddrZeros(String addr) {
if (addr == null) return null;
String[] octets = addr.split("\\.");
if (octets.length != 4) return addr;
StringBuilder builder = new StringBuilder(16);
String result = null;
for (int i = 0; i < 4; i++) {
try {
if (octets[i].length() > 3) return addr;
builder.append(Integer.parseInt(octets[i]));
} catch (NumberFormatException e) {
return addr;
}
if (i < 3) builder.append('.');
}
result = builder.toString();
return result;
}
}