Add utils to convert Inet4Address <-> int
The current utilities map the higher-order bytes of ints to the
lower-order bytes of IPv4 addresses, which makes applying masks and
generating series of addresses confusing.
For example, the current utilities would convert 1.2.3.4 to 0x04030201,
or generate 0x0080ffff for a /17 subnet mask. The utilities in this CL
convert 1.2.3.4 to 0x01020304, and a /17 subnet mask is represented as
0xffff8000.
Includes tests for all the above methods and migration of
NetworkUtilsTest to JUnit4.
Test: added tests pass
Change-Id: I5f5aa2e6e3b054b66b9dc507dab64f41be9139b1
diff --git a/core/java/android/net/NetworkUtils.java b/core/java/android/net/NetworkUtils.java
index 9a5d502..dc1f805 100644
--- a/core/java/android/net/NetworkUtils.java
+++ b/core/java/android/net/NetworkUtils.java
@@ -126,51 +126,122 @@
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
+ * @see #intToInet4AddressHTL(int)
+ * @deprecated Use either {@link #intToInet4AddressHTH(int)}
+ * or {@link #intToInet4AddressHTL(int)}
*/
+ @Deprecated
public static InetAddress intToInetAddress(int hostAddress) {
- byte[] addressBytes = { (byte)(0xff & hostAddress),
- (byte)(0xff & (hostAddress >> 8)),
- (byte)(0xff & (hostAddress >> 16)),
- (byte)(0xff & (hostAddress >> 24)) };
+ return intToInet4AddressHTL(hostAddress);
+ }
+
+ /**
+ * Convert a IPv4 address from an integer to an InetAddress (0x04030201 -> 1.2.3.4)
+ *
+ * <p>This method uses the higher-order int bytes as the lower-order IPv4 address bytes,
+ * which is an unusual convention. Consider {@link #intToInet4AddressHTH(int)} instead.
+ * @param hostAddress an int coding for an IPv4 address, where higher-order int byte is
+ * lower-order IPv4 address byte
+ */
+ public static InetAddress intToInet4AddressHTL(int hostAddress) {
+ return intToInet4AddressHTH(Integer.reverseBytes(hostAddress));
+ }
+
+ /**
+ * Convert a IPv4 address from an integer to an InetAddress (0x01020304 -> 1.2.3.4)
+ * @param hostAddress an int coding for an IPv4 address
+ */
+ public static InetAddress intToInet4AddressHTH(int hostAddress) {
+ byte[] addressBytes = { (byte) (0xff & (hostAddress >> 24)),
+ (byte) (0xff & (hostAddress >> 16)),
+ (byte) (0xff & (hostAddress >> 8)),
+ (byte) (0xff & hostAddress) };
try {
- return InetAddress.getByAddress(addressBytes);
+ return InetAddress.getByAddress(addressBytes);
} catch (UnknownHostException e) {
- throw new AssertionError();
+ 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
+ * @see #inet4AddressToIntHTL(Inet4Address)
+ * @deprecated Use either {@link #inet4AddressToIntHTH(Inet4Address)}
+ * or {@link #inet4AddressToIntHTL(Inet4Address)}
*/
+ @Deprecated
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);
+ return inet4AddressToIntHTL(inetAddr);
}
/**
- * Convert a network prefix length to an IPv4 netmask integer
- * @param prefixLength
- * @return the IPv4 netmask as an integer in network byte order
+ * Convert an IPv4 address from an InetAddress to an integer (1.2.3.4 -> 0x01020304)
+ *
+ * <p>This conversion can help order IP addresses: considering the ordering
+ * 192.0.2.1 < 192.0.2.2 < ..., resulting ints will follow that ordering if read as unsigned
+ * integers with {@link Integer#toUnsignedLong}.
+ * @param inetAddr is an InetAddress corresponding to the IPv4 address
+ * @return the IP address as integer
*/
+ public static int inet4AddressToIntHTH(Inet4Address inetAddr)
+ throws IllegalArgumentException {
+ byte [] addr = inetAddr.getAddress();
+ return ((addr[0] & 0xff) << 24) | ((addr[1] & 0xff) << 16)
+ | ((addr[2] & 0xff) << 8) | (addr[3] & 0xff);
+ }
+
+ /**
+ * Convert a IPv4 address from an InetAddress to an integer (1.2.3.4 -> 0x04030201)
+ *
+ * <p>This method stores the higher-order IPv4 address bytes in the lower-order int bytes,
+ * which is an unusual convention. Consider {@link #inet4AddressToIntHTH(Inet4Address)} instead.
+ * @param inetAddr is an InetAddress corresponding to the IPv4 address
+ * @return the IP address as integer
+ */
+ public static int inet4AddressToIntHTL(Inet4Address inetAddr) {
+ return Integer.reverseBytes(inet4AddressToIntHTH(inetAddr));
+ }
+
+ /**
+ * @see #prefixLengthToV4NetmaskIntHTL(int)
+ * @deprecated Use either {@link #prefixLengthToV4NetmaskIntHTH(int)}
+ * or {@link #prefixLengthToV4NetmaskIntHTL(int)}
+ */
+ @Deprecated
public static int prefixLengthToNetmaskInt(int prefixLength)
throws IllegalArgumentException {
+ return prefixLengthToV4NetmaskIntHTL(prefixLength);
+ }
+
+ /**
+ * Convert a network prefix length to an IPv4 netmask integer (prefixLength 17 -> 0xffff8000)
+ * @return the IPv4 netmask as an integer
+ */
+ public static int prefixLengthToV4NetmaskIntHTH(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);
+ // (int)a << b is equivalent to a << (b & 0x1f): can't shift by 32 (-1 << 32 == -1)
+ return prefixLength == 0 ? 0 : 0xffffffff << (32 - prefixLength);
+ }
+
+ /**
+ * Convert a network prefix length to an IPv4 netmask integer (prefixLength 17 -> 0x0080ffff).
+ *
+ * <p>This method stores the higher-order IPv4 address bytes in the lower-order int bytes,
+ * which is an unusual convention. Consider {@link #prefixLengthToV4NetmaskIntHTH(int)} instead.
+ * @return the IPv4 netmask as an integer
+ */
+ public static int prefixLengthToV4NetmaskIntHTL(int prefixLength)
+ throws IllegalArgumentException {
+ return Integer.reverseBytes(prefixLengthToV4NetmaskIntHTH(prefixLength));
}
/**
* Convert a IPv4 netmask integer to a prefix length
- * @param netmask as an integer in network byte order
+ * @param netmask as an integer (0xff000000 for a /8 subnet)
* @return the network prefix length
*/
public static int netmaskIntToPrefixLength(int netmask) {