// Copyright (c) 1999-2004 Brian Wellington (bwelling@xbill.org)
package org.xbill.DNS;
import java.net.*;
import java.net.Inet6Address;
/**
* Routines dealing with IP addresses. Includes functions similar to
* those in the java.net.InetAddress class.
*
* @author Brian Wellington
*/
public final class Address {
public static final int IPv4 = 1;
public static final int IPv6 = 2;
private
Address() {}
private static byte []
parseV4(String s) {
int numDigits;
int currentOctet;
byte [] values = new byte[4];
int currentValue;
int length = s.length();
currentOctet = 0;
currentValue = 0;
numDigits = 0;
for (int i = 0; i < length; i++) {
char c = s.charAt(i);
if (c >= '0' && c <= '9') {
/* Can't have more than 3 digits per octet. */
if (numDigits == 3)
return null;
/* Octets shouldn't start with 0, unless they are 0. */
if (numDigits > 0 && currentValue == 0)
return null;
numDigits++;
currentValue *= 10;
currentValue += (c - '0');
/* 255 is the maximum value for an octet. */
if (currentValue > 255)
return null;
} else if (c == '.') {
/* Can't have more than 3 dots. */
if (currentOctet == 3)
return null;
/* Two consecutive dots are bad. */
if (numDigits == 0)
return null;
values[currentOctet++] = (byte) currentValue;
currentValue = 0;
numDigits = 0;
} else
return null;
}
/* Must have 4 octets. */
if (currentOctet != 3)
return null;
/* The fourth octet can't be empty. */
if (numDigits == 0)
return null;
values[currentOctet] = (byte) currentValue;
return values;
}
private static byte []
parseV6(String s) {
int range = -1;
byte [] data = new byte[16];
String [] tokens = s.split(":", -1);
int first = 0;
int last = tokens.length - 1;
if (tokens[0].length() == 0) {
// If the first two tokens are empty, it means the string
// started with ::, which is fine. If only the first is
// empty, the string started with :, which is bad.
if (last - first > 0 && tokens[1].length() == 0)
first++;
else
return null;
}
if (tokens[last].length() == 0) {
// If the last two tokens are empty, it means the string
// ended with ::, which is fine. If only the last is
// empty, the string ended with :, which is bad.
if (last - first > 0 && tokens[last - 1].length() == 0)
last--;
else
return null;
}
if (last - first + 1 > 8)
return null;
int i, j;
for (i = first, j = 0; i <= last; i++) {
if (tokens[i].length() == 0) {
if (range >= 0)
return null;
range = j;
continue;
}
if (tokens[i].indexOf('.') >= 0) {
// An IPv4 address must be the last component
if (i < last)
return null;
// There can't have been more than 6 components.
if (i > 6)
return null;
byte [] v4addr = Address.toByteArray(tokens[i], IPv4);
if (v4addr == null)
return null;
for (int k = 0; k < 4; k++)
data[j++] = v4addr[k];
break;
}
try {
for (int k = 0; k < tokens[i].length(); k++) {
char c = tokens[i].charAt(k);
if (Character.digit(c, 16) < 0)
return null;
}
int x = Integer.parseInt(tokens[i], 16);
if (x > 0xFFFF || x < 0)
return null;
data[j++] = (byte)(x >>> 8);
data[j++] = (byte)(x & 0xFF);
}
catch (NumberFormatException e) {
return null;
}
}
if (j < 16 && range < 0)
return null;
if (range >= 0) {
int empty = 16 - j;
System.arraycopy(data, range, data, range + empty, j - range);
for (i = range; i < range + empty; i++)
data[i] = 0;
}
return data;
}
/**
* Convert a string containing an IP address to an array of 4 or 16 integers.
* @param s The address, in text format.
* @param family The address family.
* @return The address
*/
public static int []
toArray(String s, int family) {
byte [] byteArray = toByteArray(s, family);
if (byteArray == null)
return null;
int [] intArray = new int[byteArray.length];
for (int i = 0; i < byteArray.length; i++)
intArray[i] = byteArray[i] & 0xFF;
return intArray;
}
/**
* Convert a string containing an IPv4 address to an array of 4 integers.
* @param s The address, in text format.
* @return The address
*/
public static int []
toArray(String s) {
return toArray(s, IPv4);
}
/**
* Convert a string containing an IP address to an array of 4 or 16 bytes.
* @param s The address, in text format.
* @param family The address family.
* @return The address
*/
public static byte []
toByteArray(String s, int family) {
if (family == IPv4)
return parseV4(s);
else if (family == IPv6)
return parseV6(s);
else
throw new IllegalArgumentException("unknown address family");
}
/**
* Determines if a string contains a valid IP address.
* @param s The string
* @return Whether the string contains a valid IP address
*/
public static boolean
isDottedQuad(String s) {
byte [] address = Address.toByteArray(s, IPv4);
return (address != null);
}
/**
* Converts a byte array containing an IPv4 address into a dotted quad string.
* @param addr The array
* @return The string representation
*/
public static String
toDottedQuad(byte [] addr) {
return ((addr[0] & 0xFF) + "." + (addr[1] & 0xFF) + "." +
(addr[2] & 0xFF) + "." + (addr[3] & 0xFF));
}
/**
* Converts an int array containing an IPv4 address into a dotted quad string.
* @param addr The array
* @return The string representation
*/
public static String
toDottedQuad(int [] addr) {
return (addr[0] + "." + addr[1] + "." + addr[2] + "." + addr[3]);
}
private static Record []
lookupHostName(String name) throws UnknownHostException {
try {
Record [] records = new Lookup(name).run();
if (records == null)
throw new UnknownHostException("unknown host");
return records;
}
catch (TextParseException e) {
throw new UnknownHostException("invalid name");
}
}
private static InetAddress
addrFromRecord(String name, Record r) throws UnknownHostException {
ARecord a = (ARecord) r;
return InetAddress.getByAddress(name, a.getAddress().getAddress());
}
/**
* Determines the IP address of a host
* @param name The hostname to look up
* @return The first matching IP address
* @exception UnknownHostException The hostname does not have any addresses
*/
public static InetAddress
getByName(String name) throws UnknownHostException {
try {
return getByAddress(name);
} catch (UnknownHostException e) {
Record [] records = lookupHostName(name);
return addrFromRecord(name, records[0]);
}
}
/**
* Determines all IP address of a host
* @param name The hostname to look up
* @return All matching IP addresses
* @exception UnknownHostException The hostname does not have any addresses
*/
public static InetAddress []
getAllByName(String name) throws UnknownHostException {
try {
InetAddress addr = getByAddress(name);
return new InetAddress[] {addr};
} catch (UnknownHostException e) {
Record [] records = lookupHostName(name);
InetAddress [] addrs = new InetAddress[records.length];
for (int i = 0; i < records.length; i++)
addrs[i] = addrFromRecord(name, records[i]);
return addrs;
}
}
/**
* Converts an address from its string representation to an IP address.
* The address can be either IPv4 or IPv6.
* @param addr The address, in string form
* @return The IP addresses
* @exception UnknownHostException The address is not a valid IP address.
*/
public static InetAddress
getByAddress(String addr) throws UnknownHostException {
byte [] bytes;
bytes = toByteArray(addr, IPv4);
if (bytes != null)
return InetAddress.getByAddress(addr, bytes);
bytes = toByteArray(addr, IPv6);
if (bytes != null)
return InetAddress.getByAddress(addr, bytes);
throw new UnknownHostException("Invalid address: " + addr);
}
/**
* Converts an address from its string representation to an IP address in
* a particular family.
* @param addr The address, in string form
* @param family The address family, either IPv4 or IPv6.
* @return The IP addresses
* @exception UnknownHostException The address is not a valid IP address in
* the specified address family.
*/
public static InetAddress
getByAddress(String addr, int family) throws UnknownHostException {
if (family != IPv4 && family != IPv6)
throw new IllegalArgumentException("unknown address family");
byte [] bytes;
bytes = toByteArray(addr, family);
if (bytes != null)
return InetAddress.getByAddress(addr, bytes);
throw new UnknownHostException("Invalid address: " + addr);
}
/**
* Determines the hostname for an address
* @param addr The address to look up
* @return The associated host name
* @exception UnknownHostException There is no hostname for the address
*/
public static String
getHostName(InetAddress addr) throws UnknownHostException {
Name name = ReverseMap.fromAddress(addr);
Record [] records = new Lookup(name, Type.PTR).run();
if (records == null)
throw new UnknownHostException("unknown address");
PTRRecord ptr = (PTRRecord) records[0];
return ptr.getTarget().toString();
}
/**
* Returns the family of an InetAddress.
* @param address The supplied address.
* @return The family, either IPv4 or IPv6.
*/
public static int
familyOf(InetAddress address) {
if (address instanceof Inet4Address)
return IPv4;
if (address instanceof Inet6Address)
return IPv6;
throw new IllegalArgumentException("unknown address family");
}
/**
* Returns the length of an address in a particular family.
* @param family The address family, either IPv4 or IPv6.
* @return The length of addresses in that family.
*/
public static int
addressLength(int family) {
if (family == IPv4)
return 4;
if (family == IPv6)
return 16;
throw new IllegalArgumentException("unknown address family");
}
/**
* Truncates an address to the specified number of bits. For example,
* truncating the address 10.1.2.3 to 8 bits would yield 10.0.0.0.
* @param address The source address
* @param maskLength The number of bits to truncate the address to.
*/
public static InetAddress
truncate(InetAddress address, int maskLength)
{
int family = familyOf(address);
int maxMaskLength = addressLength(family) * 8;
if (maskLength < 0 || maskLength > maxMaskLength)
throw new IllegalArgumentException("invalid mask length");
if (maskLength == maxMaskLength)
return address;
byte [] bytes = address.getAddress();
for (int i = maskLength / 8 + 1; i < bytes.length; i++)
bytes[i] = 0;
int maskBits = maskLength % 8;
int bitmask = 0;
for (int i = 0; i < maskBits; i++)
bitmask |= (1 << (7 - i));
bytes[maskLength / 8] &= bitmask;
try {
return InetAddress.getByAddress(bytes);
} catch (UnknownHostException e) {
throw new IllegalArgumentException("invalid address");
}
}
}