| // Copyright (c) 1999-2004 Brian Wellington (bwelling@xbill.org) |
| |
| package org.xbill.DNS; |
| |
| import java.io.*; |
| import java.text.*; |
| |
| /** |
| * A representation of a domain name. It may either be absolute (fully |
| * qualified) or relative. |
| * |
| * @author Brian Wellington |
| */ |
| |
| public class Name implements Comparable, Serializable { |
| |
| private static final long serialVersionUID = -7257019940971525644L; |
| |
| private static final int LABEL_NORMAL = 0; |
| private static final int LABEL_COMPRESSION = 0xC0; |
| private static final int LABEL_MASK = 0xC0; |
| |
| /* The name data */ |
| private byte [] name; |
| |
| /* |
| * Effectively an 8 byte array, where the low order byte stores the number |
| * of labels and the 7 higher order bytes store per-label offsets. |
| */ |
| private long offsets; |
| |
| /* Precomputed hashcode. */ |
| private int hashcode; |
| |
| private static final byte [] emptyLabel = new byte[] {(byte)0}; |
| private static final byte [] wildLabel = new byte[] {(byte)1, (byte)'*'}; |
| |
| /** The root name */ |
| public static final Name root; |
| |
| /** The root name */ |
| public static final Name empty; |
| |
| /** The maximum length of a Name */ |
| private static final int MAXNAME = 255; |
| |
| /** The maximum length of a label a Name */ |
| private static final int MAXLABEL = 63; |
| |
| /** The maximum number of labels in a Name */ |
| private static final int MAXLABELS = 128; |
| |
| /** The maximum number of cached offsets */ |
| private static final int MAXOFFSETS = 7; |
| |
| /* Used for printing non-printable characters */ |
| private static final DecimalFormat byteFormat = new DecimalFormat(); |
| |
| /* Used to efficiently convert bytes to lowercase */ |
| private static final byte lowercase[] = new byte[256]; |
| |
| /* Used in wildcard names. */ |
| private static final Name wild; |
| |
| static { |
| byteFormat.setMinimumIntegerDigits(3); |
| for (int i = 0; i < lowercase.length; i++) { |
| if (i < 'A' || i > 'Z') |
| lowercase[i] = (byte)i; |
| else |
| lowercase[i] = (byte)(i - 'A' + 'a'); |
| } |
| root = new Name(); |
| root.appendSafe(emptyLabel, 0, 1); |
| empty = new Name(); |
| empty.name = new byte[0]; |
| wild = new Name(); |
| wild.appendSafe(wildLabel, 0, 1); |
| } |
| |
| private |
| Name() { |
| } |
| |
| private final void |
| setoffset(int n, int offset) { |
| if (n >= MAXOFFSETS) |
| return; |
| int shift = 8 * (7 - n); |
| offsets &= (~(0xFFL << shift)); |
| offsets |= ((long)offset << shift); |
| } |
| |
| private final int |
| offset(int n) { |
| if (n == 0 && getlabels() == 0) |
| return 0; |
| if (n < 0 || n >= getlabels()) |
| throw new IllegalArgumentException("label out of range"); |
| if (n < MAXOFFSETS) { |
| int shift = 8 * (7 - n); |
| return ((int)(offsets >>> shift) & 0xFF); |
| } else { |
| int pos = offset(MAXOFFSETS - 1); |
| for (int i = MAXOFFSETS - 1; i < n; i++) |
| pos += (name[pos] + 1); |
| return (pos); |
| } |
| } |
| |
| private final void |
| setlabels(int labels) { |
| offsets &= ~(0xFF); |
| offsets |= labels; |
| } |
| |
| private final int |
| getlabels() { |
| return (int)(offsets & 0xFF); |
| } |
| |
| private static final void |
| copy(Name src, Name dst) { |
| if (src.offset(0) == 0) { |
| dst.name = src.name; |
| dst.offsets = src.offsets; |
| } else { |
| int offset0 = src.offset(0); |
| int namelen = src.name.length - offset0; |
| int labels = src.labels(); |
| dst.name = new byte[namelen]; |
| System.arraycopy(src.name, offset0, dst.name, 0, namelen); |
| for (int i = 0; i < labels && i < MAXOFFSETS; i++) |
| dst.setoffset(i, src.offset(i) - offset0); |
| dst.setlabels(labels); |
| } |
| } |
| |
| private final void |
| append(byte [] array, int start, int n) throws NameTooLongException { |
| int length = (name == null ? 0 : (name.length - offset(0))); |
| int alength = 0; |
| for (int i = 0, pos = start; i < n; i++) { |
| int len = array[pos]; |
| if (len > MAXLABEL) |
| throw new IllegalStateException("invalid label"); |
| len++; |
| pos += len; |
| alength += len; |
| } |
| int newlength = length + alength; |
| if (newlength > MAXNAME) |
| throw new NameTooLongException(); |
| int labels = getlabels(); |
| int newlabels = labels + n; |
| if (newlabels > MAXLABELS) |
| throw new IllegalStateException("too many labels"); |
| byte [] newname = new byte[newlength]; |
| if (length != 0) |
| System.arraycopy(name, offset(0), newname, 0, length); |
| System.arraycopy(array, start, newname, length, alength); |
| name = newname; |
| for (int i = 0, pos = length; i < n; i++) { |
| setoffset(labels + i, pos); |
| pos += (newname[pos] + 1); |
| } |
| setlabels(newlabels); |
| } |
| |
| private static TextParseException |
| parseException(String str, String message) { |
| return new TextParseException("'" + str + "': " + message); |
| } |
| |
| private final void |
| appendFromString(String fullName, byte [] array, int start, int n) |
| throws TextParseException |
| { |
| try { |
| append(array, start, n); |
| } |
| catch (NameTooLongException e) { |
| throw parseException(fullName, "Name too long"); |
| } |
| } |
| |
| private final void |
| appendSafe(byte [] array, int start, int n) { |
| try { |
| append(array, start, n); |
| } |
| catch (NameTooLongException e) { |
| } |
| } |
| |
| /** |
| * Create a new name from a string and an origin. This does not automatically |
| * make the name absolute; it will be absolute if it has a trailing dot or an |
| * absolute origin is appended. |
| * @param s The string to be converted |
| * @param origin If the name is not absolute, the origin to be appended. |
| * @throws TextParseException The name is invalid. |
| */ |
| public |
| Name(String s, Name origin) throws TextParseException { |
| if (s.equals("")) |
| throw parseException(s, "empty name"); |
| else if (s.equals("@")) { |
| if (origin == null) |
| copy(empty, this); |
| else |
| copy(origin, this); |
| return; |
| } else if (s.equals(".")) { |
| copy(root, this); |
| return; |
| } |
| int labelstart = -1; |
| int pos = 1; |
| byte [] label = new byte[MAXLABEL + 1]; |
| boolean escaped = false; |
| int digits = 0; |
| int intval = 0; |
| boolean absolute = false; |
| for (int i = 0; i < s.length(); i++) { |
| byte b = (byte) s.charAt(i); |
| if (escaped) { |
| if (b >= '0' && b <= '9' && digits < 3) { |
| digits++; |
| intval *= 10; |
| intval += (b - '0'); |
| if (intval > 255) |
| throw parseException(s, "bad escape"); |
| if (digits < 3) |
| continue; |
| b = (byte) intval; |
| } |
| else if (digits > 0 && digits < 3) |
| throw parseException(s, "bad escape"); |
| if (pos > MAXLABEL) |
| throw parseException(s, "label too long"); |
| labelstart = pos; |
| label[pos++] = b; |
| escaped = false; |
| } else if (b == '\\') { |
| escaped = true; |
| digits = 0; |
| intval = 0; |
| } else if (b == '.') { |
| if (labelstart == -1) |
| throw parseException(s, "invalid empty label"); |
| label[0] = (byte)(pos - 1); |
| appendFromString(s, label, 0, 1); |
| labelstart = -1; |
| pos = 1; |
| } else { |
| if (labelstart == -1) |
| labelstart = i; |
| if (pos > MAXLABEL) |
| throw parseException(s, "label too long"); |
| label[pos++] = b; |
| } |
| } |
| if (digits > 0 && digits < 3) |
| throw parseException(s, "bad escape"); |
| if (escaped) |
| throw parseException(s, "bad escape"); |
| if (labelstart == -1) { |
| appendFromString(s, emptyLabel, 0, 1); |
| absolute = true; |
| } else { |
| label[0] = (byte)(pos - 1); |
| appendFromString(s, label, 0, 1); |
| } |
| if (origin != null && !absolute) |
| appendFromString(s, origin.name, 0, origin.getlabels()); |
| } |
| |
| /** |
| * Create a new name from a string. This does not automatically make the name |
| * absolute; it will be absolute if it has a trailing dot. |
| * @param s The string to be converted |
| * @throws TextParseException The name is invalid. |
| */ |
| public |
| Name(String s) throws TextParseException { |
| this(s, null); |
| } |
| |
| /** |
| * Create a new name from a string and an origin. This does not automatically |
| * make the name absolute; it will be absolute if it has a trailing dot or an |
| * absolute origin is appended. This is identical to the constructor, except |
| * that it will avoid creating new objects in some cases. |
| * @param s The string to be converted |
| * @param origin If the name is not absolute, the origin to be appended. |
| * @throws TextParseException The name is invalid. |
| */ |
| public static Name |
| fromString(String s, Name origin) throws TextParseException { |
| if (s.equals("@") && origin != null) |
| return origin; |
| else if (s.equals(".")) |
| return (root); |
| |
| return new Name(s, origin); |
| } |
| |
| /** |
| * Create a new name from a string. This does not automatically make the name |
| * absolute; it will be absolute if it has a trailing dot. This is identical |
| * to the constructor, except that it will avoid creating new objects in some |
| * cases. |
| * @param s The string to be converted |
| * @throws TextParseException The name is invalid. |
| */ |
| public static Name |
| fromString(String s) throws TextParseException { |
| return fromString(s, null); |
| } |
| |
| /** |
| * Create a new name from a constant string. This should only be used when |
| the name is known to be good - that is, when it is constant. |
| * @param s The string to be converted |
| * @throws IllegalArgumentException The name is invalid. |
| */ |
| public static Name |
| fromConstantString(String s) { |
| try { |
| return fromString(s, null); |
| } |
| catch (TextParseException e) { |
| throw new IllegalArgumentException("Invalid name '" + s + "'"); |
| } |
| } |
| |
| /** |
| * Create a new name from DNS a wire format message |
| * @param in A stream containing the DNS message which is currently |
| * positioned at the start of the name to be read. |
| */ |
| public |
| Name(DNSInput in) throws WireParseException { |
| int len, pos; |
| boolean done = false; |
| byte [] label = new byte[MAXLABEL + 1]; |
| boolean savedState = false; |
| |
| while (!done) { |
| len = in.readU8(); |
| switch (len & LABEL_MASK) { |
| case LABEL_NORMAL: |
| if (getlabels() >= MAXLABELS) |
| throw new WireParseException("too many labels"); |
| if (len == 0) { |
| append(emptyLabel, 0, 1); |
| done = true; |
| } else { |
| label[0] = (byte)len; |
| in.readByteArray(label, 1, len); |
| append(label, 0, 1); |
| } |
| break; |
| case LABEL_COMPRESSION: |
| pos = in.readU8(); |
| pos += ((len & ~LABEL_MASK) << 8); |
| if (Options.check("verbosecompression")) |
| System.err.println("currently " + in.current() + |
| ", pointer to " + pos); |
| |
| if (pos >= in.current() - 2) |
| throw new WireParseException("bad compression"); |
| if (!savedState) { |
| in.save(); |
| savedState = true; |
| } |
| in.jump(pos); |
| if (Options.check("verbosecompression")) |
| System.err.println("current name '" + this + |
| "', seeking to " + pos); |
| break; |
| default: |
| throw new WireParseException("bad label type"); |
| } |
| } |
| if (savedState) { |
| in.restore(); |
| } |
| } |
| |
| /** |
| * Create a new name from DNS wire format |
| * @param b A byte array containing the wire format of the name. |
| */ |
| public |
| Name(byte [] b) throws IOException { |
| this(new DNSInput(b)); |
| } |
| |
| /** |
| * Create a new name by removing labels from the beginning of an existing Name |
| * @param src An existing Name |
| * @param n The number of labels to remove from the beginning in the copy |
| */ |
| public |
| Name(Name src, int n) { |
| int slabels = src.labels(); |
| if (n > slabels) |
| throw new IllegalArgumentException("attempted to remove too " + |
| "many labels"); |
| name = src.name; |
| setlabels(slabels - n); |
| for (int i = 0; i < MAXOFFSETS && i < slabels - n; i++) |
| setoffset(i, src.offset(i + n)); |
| } |
| |
| /** |
| * Creates a new name by concatenating two existing names. |
| * @param prefix The prefix name. |
| * @param suffix The suffix name. |
| * @return The concatenated name. |
| * @throws NameTooLongException The name is too long. |
| */ |
| public static Name |
| concatenate(Name prefix, Name suffix) throws NameTooLongException { |
| if (prefix.isAbsolute()) |
| return (prefix); |
| Name newname = new Name(); |
| copy(prefix, newname); |
| newname.append(suffix.name, suffix.offset(0), suffix.getlabels()); |
| return newname; |
| } |
| |
| /** |
| * If this name is a subdomain of origin, return a new name relative to |
| * origin with the same value. Otherwise, return the existing name. |
| * @param origin The origin to remove. |
| * @return The possibly relativized name. |
| */ |
| public Name |
| relativize(Name origin) { |
| if (origin == null || !subdomain(origin)) |
| return this; |
| Name newname = new Name(); |
| copy(this, newname); |
| int length = length() - origin.length(); |
| int labels = newname.labels() - origin.labels(); |
| newname.setlabels(labels); |
| newname.name = new byte[length]; |
| System.arraycopy(name, offset(0), newname.name, 0, length); |
| return newname; |
| } |
| |
| /** |
| * Generates a new Name with the first n labels replaced by a wildcard |
| * @return The wildcard name |
| */ |
| public Name |
| wild(int n) { |
| if (n < 1) |
| throw new IllegalArgumentException("must replace 1 or more " + |
| "labels"); |
| try { |
| Name newname = new Name(); |
| copy(wild, newname); |
| newname.append(name, offset(n), getlabels() - n); |
| return newname; |
| } |
| catch (NameTooLongException e) { |
| throw new IllegalStateException |
| ("Name.wild: concatenate failed"); |
| } |
| } |
| |
| /** |
| * Generates a new Name to be used when following a DNAME. |
| * @param dname The DNAME record to follow. |
| * @return The constructed name. |
| * @throws NameTooLongException The resulting name is too long. |
| */ |
| public Name |
| fromDNAME(DNAMERecord dname) throws NameTooLongException { |
| Name dnameowner = dname.getName(); |
| Name dnametarget = dname.getTarget(); |
| if (!subdomain(dnameowner)) |
| return null; |
| |
| int plabels = labels() - dnameowner.labels(); |
| int plength = length() - dnameowner.length(); |
| int pstart = offset(0); |
| |
| int dlabels = dnametarget.labels(); |
| int dlength = dnametarget.length(); |
| |
| if (plength + dlength > MAXNAME) |
| throw new NameTooLongException(); |
| |
| Name newname = new Name(); |
| newname.setlabels(plabels + dlabels); |
| newname.name = new byte[plength + dlength]; |
| System.arraycopy(name, pstart, newname.name, 0, plength); |
| System.arraycopy(dnametarget.name, 0, newname.name, plength, dlength); |
| |
| for (int i = 0, pos = 0; i < MAXOFFSETS && i < plabels + dlabels; i++) { |
| newname.setoffset(i, pos); |
| pos += (newname.name[pos] + 1); |
| } |
| return newname; |
| } |
| |
| /** |
| * Is this name a wildcard? |
| */ |
| public boolean |
| isWild() { |
| if (labels() == 0) |
| return false; |
| return (name[0] == (byte)1 && name[1] == (byte)'*'); |
| } |
| |
| /** |
| * Is this name absolute? |
| */ |
| public boolean |
| isAbsolute() { |
| if (labels() == 0) |
| return false; |
| return (name[name.length - 1] == 0); |
| } |
| |
| /** |
| * The length of the name. |
| */ |
| public short |
| length() { |
| if (getlabels() == 0) |
| return 0; |
| return (short)(name.length - offset(0)); |
| } |
| |
| /** |
| * The number of labels in the name. |
| */ |
| public int |
| labels() { |
| return getlabels(); |
| } |
| |
| /** |
| * Is the current Name a subdomain of the specified name? |
| */ |
| public boolean |
| subdomain(Name domain) { |
| int labels = labels(); |
| int dlabels = domain.labels(); |
| if (dlabels > labels) |
| return false; |
| if (dlabels == labels) |
| return equals(domain); |
| return domain.equals(name, offset(labels - dlabels)); |
| } |
| |
| private String |
| byteString(byte [] array, int pos) { |
| StringBuffer sb = new StringBuffer(); |
| int len = array[pos++]; |
| for (int i = pos; i < pos + len; i++) { |
| int b = array[i] & 0xFF; |
| if (b <= 0x20 || b >= 0x7f) { |
| sb.append('\\'); |
| sb.append(byteFormat.format(b)); |
| } |
| else if (b == '"' || b == '(' || b == ')' || b == '.' || |
| b == ';' || b == '\\' || b == '@' || b == '$') |
| { |
| sb.append('\\'); |
| sb.append((char)b); |
| } |
| else |
| sb.append((char)b); |
| } |
| return sb.toString(); |
| } |
| |
| /** |
| * Convert a Name to a String |
| * @return The representation of this name as a (printable) String. |
| */ |
| public String |
| toString() { |
| int labels = labels(); |
| if (labels == 0) |
| return "@"; |
| else if (labels == 1 && name[offset(0)] == 0) |
| return "."; |
| StringBuffer sb = new StringBuffer(); |
| for (int i = 0, pos = offset(0); i < labels; i++) { |
| int len = name[pos]; |
| if (len > MAXLABEL) |
| throw new IllegalStateException("invalid label"); |
| if (len == 0) |
| break; |
| sb.append(byteString(name, pos)); |
| sb.append('.'); |
| pos += (1 + len); |
| } |
| if (!isAbsolute()) |
| sb.deleteCharAt(sb.length() - 1); |
| return sb.toString(); |
| } |
| |
| /** |
| * Retrieve the nth label of a Name. This makes a copy of the label; changing |
| * this does not change the Name. |
| * @param n The label to be retrieved. The first label is 0. |
| */ |
| public byte [] |
| getLabel(int n) { |
| int pos = offset(n); |
| byte len = (byte)(name[pos] + 1); |
| byte [] label = new byte[len]; |
| System.arraycopy(name, pos, label, 0, len); |
| return label; |
| } |
| |
| /** |
| * Convert the nth label in a Name to a String |
| * @param n The label to be converted to a (printable) String. The first |
| * label is 0. |
| */ |
| public String |
| getLabelString(int n) { |
| int pos = offset(n); |
| return byteString(name, pos); |
| } |
| |
| /** |
| * Emit a Name in DNS wire format |
| * @param out The output stream containing the DNS message. |
| * @param c The compression context, or null of no compression is desired. |
| * @throws IllegalArgumentException The name is not absolute. |
| */ |
| public void |
| toWire(DNSOutput out, Compression c) { |
| if (!isAbsolute()) |
| throw new IllegalArgumentException("toWire() called on " + |
| "non-absolute name"); |
| |
| int labels = labels(); |
| for (int i = 0; i < labels - 1; i++) { |
| Name tname; |
| if (i == 0) |
| tname = this; |
| else |
| tname = new Name(this, i); |
| int pos = -1; |
| if (c != null) |
| pos = c.get(tname); |
| if (pos >= 0) { |
| pos |= (LABEL_MASK << 8); |
| out.writeU16(pos); |
| return; |
| } else { |
| if (c != null) |
| c.add(out.current(), tname); |
| int off = offset(i); |
| out.writeByteArray(name, off, name[off] + 1); |
| } |
| } |
| out.writeU8(0); |
| } |
| |
| /** |
| * Emit a Name in DNS wire format |
| * @throws IllegalArgumentException The name is not absolute. |
| */ |
| public byte [] |
| toWire() { |
| DNSOutput out = new DNSOutput(); |
| toWire(out, null); |
| return out.toByteArray(); |
| } |
| |
| /** |
| * Emit a Name in canonical DNS wire format (all lowercase) |
| * @param out The output stream to which the message is written. |
| */ |
| public void |
| toWireCanonical(DNSOutput out) { |
| byte [] b = toWireCanonical(); |
| out.writeByteArray(b); |
| } |
| |
| /** |
| * Emit a Name in canonical DNS wire format (all lowercase) |
| * @return The canonical form of the name. |
| */ |
| public byte [] |
| toWireCanonical() { |
| int labels = labels(); |
| if (labels == 0) |
| return (new byte[0]); |
| byte [] b = new byte[name.length - offset(0)]; |
| for (int i = 0, spos = offset(0), dpos = 0; i < labels; i++) { |
| int len = name[spos]; |
| if (len > MAXLABEL) |
| throw new IllegalStateException("invalid label"); |
| b[dpos++] = name[spos++]; |
| for (int j = 0; j < len; j++) |
| b[dpos++] = lowercase[(name[spos++] & 0xFF)]; |
| } |
| return b; |
| } |
| |
| /** |
| * Emit a Name in DNS wire format |
| * @param out The output stream containing the DNS message. |
| * @param c The compression context, or null of no compression is desired. |
| * @param canonical If true, emit the name in canonicalized form |
| * (all lowercase). |
| * @throws IllegalArgumentException The name is not absolute. |
| */ |
| public void |
| toWire(DNSOutput out, Compression c, boolean canonical) { |
| if (canonical) |
| toWireCanonical(out); |
| else |
| toWire(out, c); |
| } |
| |
| private final boolean |
| equals(byte [] b, int bpos) { |
| int labels = labels(); |
| for (int i = 0, pos = offset(0); i < labels; i++) { |
| if (name[pos] != b[bpos]) |
| return false; |
| int len = name[pos++]; |
| bpos++; |
| if (len > MAXLABEL) |
| throw new IllegalStateException("invalid label"); |
| for (int j = 0; j < len; j++) |
| if (lowercase[(name[pos++] & 0xFF)] != |
| lowercase[(b[bpos++] & 0xFF)]) |
| return false; |
| } |
| return true; |
| } |
| |
| /** |
| * Are these two Names equivalent? |
| */ |
| public boolean |
| equals(Object arg) { |
| if (arg == this) |
| return true; |
| if (arg == null || !(arg instanceof Name)) |
| return false; |
| Name d = (Name) arg; |
| if (d.hashcode == 0) |
| d.hashCode(); |
| if (hashcode == 0) |
| hashCode(); |
| if (d.hashcode != hashcode) |
| return false; |
| if (d.labels() != labels()) |
| return false; |
| return equals(d.name, d.offset(0)); |
| } |
| |
| /** |
| * Computes a hashcode based on the value |
| */ |
| public int |
| hashCode() { |
| if (hashcode != 0) |
| return (hashcode); |
| int code = 0; |
| for (int i = offset(0); i < name.length; i++) |
| code += ((code << 3) + lowercase[(name[i] & 0xFF)]); |
| hashcode = code; |
| return hashcode; |
| } |
| |
| /** |
| * Compares this Name to another Object. |
| * @param o The Object to be compared. |
| * @return The value 0 if the argument is a name equivalent to this name; |
| * a value less than 0 if the argument is less than this name in the canonical |
| * ordering, and a value greater than 0 if the argument is greater than this |
| * name in the canonical ordering. |
| * @throws ClassCastException if the argument is not a Name. |
| */ |
| public int |
| compareTo(Object o) { |
| Name arg = (Name) o; |
| |
| if (this == arg) |
| return (0); |
| |
| int labels = labels(); |
| int alabels = arg.labels(); |
| int compares = labels > alabels ? alabels : labels; |
| |
| for (int i = 1; i <= compares; i++) { |
| int start = offset(labels - i); |
| int astart = arg.offset(alabels - i); |
| int length = name[start]; |
| int alength = arg.name[astart]; |
| for (int j = 0; j < length && j < alength; j++) { |
| int n = lowercase[(name[j + start + 1]) & 0xFF] - |
| lowercase[(arg.name[j + astart + 1]) & 0xFF]; |
| if (n != 0) |
| return (n); |
| } |
| if (length != alength) |
| return (length - alength); |
| } |
| return (labels - alabels); |
| } |
| |
| } |