| // INetAddress.java -- An Internet Protocol (IP) address. |
| |
| /* Copyright (C) 1998, 1999, 2000 Free Software Foundation |
| |
| This file is part of libgcj. |
| |
| This software is copyrighted work licensed under the terms of the |
| Libgcj License. Please consult the file "LIBGCJ_LICENSE" for |
| details. */ |
| |
| package java.net; |
| import java.io.ObjectInputStream; |
| import java.io.ObjectOutputStream; |
| import java.io.IOException; |
| |
| /** |
| * @author Per Bothner |
| * @date January 6, 1999. |
| */ |
| |
| /* |
| * Written using on-line Java Platform 1.2 API Specification, as well |
| * as "The Java Class Libraries", 2nd edition (Addison-Wesley, 1998). |
| * (The latter turns out to have some errors ...) |
| * Status: Believed complete and correct. |
| */ |
| |
| public final class InetAddress implements java.io.Serializable |
| { |
| // The Serialized Form specifies that an int 'address' is saved/restored. |
| // This class uses a byte array internally so we'll just do the conversion |
| // at serialization time and leave the rest of the algorithm as is. |
| private int address; |
| transient byte[] addr; |
| String hostName; |
| // The field 'family' seems to be the AF_ value. |
| // FIXME: Much of the code in the other java.net classes does not make |
| // use of this family field. A better implementation would be to make |
| // use of getaddrinfo() and have other methods just check the family |
| // field rather than examining the length of the address each time. |
| int family; |
| private static final long serialVersionUID = 3286316764910316507L; |
| |
| private void readObject(ObjectInputStream ois) |
| throws IOException, ClassNotFoundException |
| { |
| ois.defaultReadObject(); |
| addr = new byte[4]; |
| addr[3] = (byte) address; |
| for (int i = 2; i >= 0; --i) |
| addr[i] = (byte) (address >>= 8); |
| // Ignore family from serialized data. Since the saved address is 32 bits |
| // the deserialized object will have an IPv4 address i.e. AF_INET family. |
| // FIXME: An alternative is to call the aton method on the deserialized |
| // hostname to get a new address. The Serialized Form doc is silent |
| // on how these fields are used. |
| family = getFamily (addr); |
| } |
| |
| private void writeObject(ObjectOutputStream oos) throws IOException |
| { |
| // Build a 32 bit address from the last 4 bytes of a 4 byte IPv4 address |
| // or a 16 byte IPv6 address. |
| int len = addr.length; |
| int i = len - 4; |
| for (; i < len; i++) |
| address = address << 8 | (((int) addr[i]) & 0xFF); |
| oos.defaultWriteObject(); |
| } |
| |
| private static native int getFamily (byte[] address); |
| |
| InetAddress (byte[] address, String hostname) |
| { |
| addr = address; |
| hostName = hostname; |
| if (address != null) |
| family = getFamily (address); |
| } |
| |
| public boolean isMulticastAddress () |
| { |
| int len = addr.length; |
| if (len == 4) |
| return (addr[0] & 0xF0) == 0xE0; |
| if (len == 16) |
| return addr[0] == (byte) 0xFF; |
| return false; |
| } |
| |
| public String getHostName () |
| { |
| if (hostName == null) |
| lookup (null, this, false); |
| return hostName; |
| } |
| |
| public byte[] getAddress () |
| { |
| // An experiment shows that JDK1.2 returns a different byte array each |
| // time. This makes sense, in terms of security. |
| return (byte[]) addr.clone(); |
| } |
| |
| /* Helper function due to a CNI limitation. */ |
| private static InetAddress[] allocArray (int count) |
| { |
| return new InetAddress[count]; |
| } |
| |
| /* Helper function due to a CNI limitation. */ |
| private static SecurityException checkConnect (String hostname) |
| { |
| SecurityManager s = System.getSecurityManager(); |
| if (s == null) |
| return null; |
| try |
| { |
| s.checkConnect(hostname, -1); |
| return null; |
| } |
| catch (SecurityException ex) |
| { |
| return ex; |
| } |
| } |
| |
| public String getHostAddress () |
| { |
| StringBuffer sbuf = new StringBuffer(40); |
| int len = addr.length; |
| int i = 0; |
| if (len == 16) |
| { // An IPv6 address. |
| for (; ; i += 2) |
| { |
| if (i >= 16) |
| return sbuf.toString(); |
| int x = ((addr[i] & 0xFF) << 8) | (addr[i+1] & 0xFF); |
| boolean empty = sbuf.length() == 0; |
| if (empty) |
| { |
| if (i == 10 && x == 0xFFFF) |
| { // IPv4-mapped IPv6 address. |
| sbuf.append(":FFFF:"); |
| break; // Continue as IPv4 address; |
| } |
| else if (i == 12) |
| { // IPv4-compatible IPv6 address. |
| sbuf.append(':'); |
| break; // Continue as IPv4 address. |
| } |
| else if (i > 0) |
| sbuf.append("::"); |
| } |
| else |
| sbuf.append(':'); |
| if (x != 0 || i >= 14) |
| sbuf.append(Integer.toHexString(x).toUpperCase()); |
| } |
| } |
| for ( ; ; ) |
| { |
| sbuf.append(addr[i] & 0xFF); |
| i++; |
| if (i == len) |
| break; |
| sbuf.append('.'); |
| } |
| return sbuf.toString(); |
| } |
| |
| public int hashCode() |
| { |
| // There hashing algorithm is not specified, but a simple experiment |
| // shows that it is equal to the address, as a 32-bit big-endian integer. |
| int hash = 0; |
| int len = addr.length; |
| int i = len > 4 ? len - 4 : 0; |
| for ( ; i < len; i++) |
| hash = (hash << 8) | (addr[i] & 0xFF); |
| return hash; |
| } |
| |
| public boolean equals (Object obj) |
| { |
| if (obj == null || ! (obj instanceof InetAddress)) |
| return false; |
| // "The Java Class Libraries" 2nd edition says "If a machine has |
| // multiple names instances of InetAddress for different name of |
| // that same machine are not equal. This is because they have |
| // different host names." This violates the description in the |
| // JDK 1.2 API documentation. A little experiementation |
| // shows that the latter is correct. |
| byte[] addr1 = addr; |
| byte[] addr2 = ((InetAddress) obj).addr; |
| if (addr1.length != addr2.length) |
| return false; |
| for (int i = addr1.length; --i >= 0; ) |
| if (addr1[i] != addr2[i]) |
| return false; |
| return true; |
| } |
| |
| public String toString() |
| { |
| return getHostName()+'/'+getHostAddress(); |
| } |
| |
| /** If host is a valid numeric IP address, return the numeric address. |
| * Otherwise, return null. */ |
| private static native byte[] aton (String host); |
| |
| private static native InetAddress[] lookup |
| (String hostname, InetAddress addr, boolean all); |
| |
| public static InetAddress getByName (String host) |
| throws UnknownHostException |
| { |
| if (host == null) |
| return getLocalHost(); |
| byte[] address = aton(host); |
| if (address != null) |
| return new InetAddress(address, null); |
| InetAddress iaddr = new InetAddress(null, host); |
| lookup(host, iaddr, false); |
| return iaddr; |
| } |
| |
| public static InetAddress[] getAllByName (String host) |
| throws UnknownHostException |
| { |
| byte[] address = aton(host); |
| if (address != null) |
| { |
| InetAddress[] result = new InetAddress[1]; |
| result[0] = new InetAddress(address, null); |
| return result; |
| } |
| return lookup(host, null, true); |
| } |
| |
| private static final byte[] localhostAddress = { 127, 0, 0, 1 }; |
| |
| private static native String getLocalHostname (); |
| |
| private static InetAddress localhost = null; |
| |
| public static InetAddress getLocalHost() throws UnknownHostException |
| { |
| SecurityManager s = System.getSecurityManager(); |
| // Experimentation shows that JDK1.2 does cache the result. |
| // However, if there is a security manager, and the cached result |
| // is other than "localhost", we need to check again. |
| if (localhost == null |
| || (s != null && localhost.addr != localhostAddress)) |
| getLocalHost(s); |
| return localhost; |
| } |
| |
| private static synchronized void getLocalHost(SecurityManager s) |
| throws UnknownHostException |
| { |
| // Check the localhost cache again, now that we've synchronized. |
| if (s == null && localhost != null) |
| return; |
| String hostname = getLocalHostname(); |
| if (s != null) |
| { |
| // "The Java Class Libraries" suggests that if the security |
| // manager disallows getting the local host name, then |
| // we use the loopback host. |
| // However, the JDK 1.2 API claims to throw SecurityException, |
| // which seems to suggest SecurityException is *not* caught. |
| // In this case, experimentation shows that former is correct. |
| try |
| { |
| // This is wrong, if the name returned from getLocalHostname() |
| // is not a fully qualified name. FIXME. |
| s.checkConnect(hostname, -1); |
| } |
| catch (SecurityException ex) |
| { |
| hostname = null; |
| } |
| } |
| if (hostname != null) |
| { |
| try |
| { |
| localhost = new InetAddress(null, null); |
| lookup(hostname, localhost, false); |
| } |
| catch (Exception ex) |
| { |
| } |
| } |
| if (localhost == null) |
| localhost = new InetAddress (localhostAddress, "localhost"); |
| } |
| } |