Shuyi Chen | d7955ce | 2013-05-22 14:51:55 -0700 | [diff] [blame] | 1 | // Copyright (c) 1999-2004 Brian Wellington (bwelling@xbill.org) |
| 2 | |
| 3 | package org.xbill.DNS; |
| 4 | |
| 5 | import java.io.*; |
| 6 | import java.text.*; |
| 7 | |
| 8 | /** |
| 9 | * A representation of a domain name. It may either be absolute (fully |
| 10 | * qualified) or relative. |
| 11 | * |
| 12 | * @author Brian Wellington |
| 13 | */ |
| 14 | |
| 15 | public class Name implements Comparable, Serializable { |
| 16 | |
| 17 | private static final long serialVersionUID = -7257019940971525644L; |
| 18 | |
| 19 | private static final int LABEL_NORMAL = 0; |
| 20 | private static final int LABEL_COMPRESSION = 0xC0; |
| 21 | private static final int LABEL_MASK = 0xC0; |
| 22 | |
| 23 | /* The name data */ |
| 24 | private byte [] name; |
| 25 | |
| 26 | /* |
| 27 | * Effectively an 8 byte array, where the low order byte stores the number |
| 28 | * of labels and the 7 higher order bytes store per-label offsets. |
| 29 | */ |
| 30 | private long offsets; |
| 31 | |
| 32 | /* Precomputed hashcode. */ |
| 33 | private int hashcode; |
| 34 | |
| 35 | private static final byte [] emptyLabel = new byte[] {(byte)0}; |
| 36 | private static final byte [] wildLabel = new byte[] {(byte)1, (byte)'*'}; |
| 37 | |
| 38 | /** The root name */ |
| 39 | public static final Name root; |
| 40 | |
| 41 | /** The root name */ |
| 42 | public static final Name empty; |
| 43 | |
| 44 | /** The maximum length of a Name */ |
| 45 | private static final int MAXNAME = 255; |
| 46 | |
| 47 | /** The maximum length of a label a Name */ |
| 48 | private static final int MAXLABEL = 63; |
| 49 | |
| 50 | /** The maximum number of labels in a Name */ |
| 51 | private static final int MAXLABELS = 128; |
| 52 | |
| 53 | /** The maximum number of cached offsets */ |
| 54 | private static final int MAXOFFSETS = 7; |
| 55 | |
| 56 | /* Used for printing non-printable characters */ |
| 57 | private static final DecimalFormat byteFormat = new DecimalFormat(); |
| 58 | |
| 59 | /* Used to efficiently convert bytes to lowercase */ |
| 60 | private static final byte lowercase[] = new byte[256]; |
| 61 | |
| 62 | /* Used in wildcard names. */ |
| 63 | private static final Name wild; |
| 64 | |
| 65 | static { |
| 66 | byteFormat.setMinimumIntegerDigits(3); |
| 67 | for (int i = 0; i < lowercase.length; i++) { |
| 68 | if (i < 'A' || i > 'Z') |
| 69 | lowercase[i] = (byte)i; |
| 70 | else |
| 71 | lowercase[i] = (byte)(i - 'A' + 'a'); |
| 72 | } |
| 73 | root = new Name(); |
| 74 | root.appendSafe(emptyLabel, 0, 1); |
| 75 | empty = new Name(); |
| 76 | empty.name = new byte[0]; |
| 77 | wild = new Name(); |
| 78 | wild.appendSafe(wildLabel, 0, 1); |
| 79 | } |
| 80 | |
| 81 | private |
| 82 | Name() { |
| 83 | } |
| 84 | |
| 85 | private final void |
| 86 | setoffset(int n, int offset) { |
| 87 | if (n >= MAXOFFSETS) |
| 88 | return; |
| 89 | int shift = 8 * (7 - n); |
| 90 | offsets &= (~(0xFFL << shift)); |
| 91 | offsets |= ((long)offset << shift); |
| 92 | } |
| 93 | |
| 94 | private final int |
| 95 | offset(int n) { |
| 96 | if (n == 0 && getlabels() == 0) |
| 97 | return 0; |
| 98 | if (n < 0 || n >= getlabels()) |
| 99 | throw new IllegalArgumentException("label out of range"); |
| 100 | if (n < MAXOFFSETS) { |
| 101 | int shift = 8 * (7 - n); |
| 102 | return ((int)(offsets >>> shift) & 0xFF); |
| 103 | } else { |
| 104 | int pos = offset(MAXOFFSETS - 1); |
| 105 | for (int i = MAXOFFSETS - 1; i < n; i++) |
| 106 | pos += (name[pos] + 1); |
| 107 | return (pos); |
| 108 | } |
| 109 | } |
| 110 | |
| 111 | private final void |
| 112 | setlabels(int labels) { |
| 113 | offsets &= ~(0xFF); |
| 114 | offsets |= labels; |
| 115 | } |
| 116 | |
| 117 | private final int |
| 118 | getlabels() { |
| 119 | return (int)(offsets & 0xFF); |
| 120 | } |
| 121 | |
| 122 | private static final void |
| 123 | copy(Name src, Name dst) { |
| 124 | if (src.offset(0) == 0) { |
| 125 | dst.name = src.name; |
| 126 | dst.offsets = src.offsets; |
| 127 | } else { |
| 128 | int offset0 = src.offset(0); |
| 129 | int namelen = src.name.length - offset0; |
| 130 | int labels = src.labels(); |
| 131 | dst.name = new byte[namelen]; |
| 132 | System.arraycopy(src.name, offset0, dst.name, 0, namelen); |
| 133 | for (int i = 0; i < labels && i < MAXOFFSETS; i++) |
| 134 | dst.setoffset(i, src.offset(i) - offset0); |
| 135 | dst.setlabels(labels); |
| 136 | } |
| 137 | } |
| 138 | |
| 139 | private final void |
| 140 | append(byte [] array, int start, int n) throws NameTooLongException { |
| 141 | int length = (name == null ? 0 : (name.length - offset(0))); |
| 142 | int alength = 0; |
| 143 | for (int i = 0, pos = start; i < n; i++) { |
| 144 | int len = array[pos]; |
| 145 | if (len > MAXLABEL) |
| 146 | throw new IllegalStateException("invalid label"); |
| 147 | len++; |
| 148 | pos += len; |
| 149 | alength += len; |
| 150 | } |
| 151 | int newlength = length + alength; |
| 152 | if (newlength > MAXNAME) |
| 153 | throw new NameTooLongException(); |
| 154 | int labels = getlabels(); |
| 155 | int newlabels = labels + n; |
| 156 | if (newlabels > MAXLABELS) |
| 157 | throw new IllegalStateException("too many labels"); |
| 158 | byte [] newname = new byte[newlength]; |
| 159 | if (length != 0) |
| 160 | System.arraycopy(name, offset(0), newname, 0, length); |
| 161 | System.arraycopy(array, start, newname, length, alength); |
| 162 | name = newname; |
| 163 | for (int i = 0, pos = length; i < n; i++) { |
| 164 | setoffset(labels + i, pos); |
| 165 | pos += (newname[pos] + 1); |
| 166 | } |
| 167 | setlabels(newlabels); |
| 168 | } |
| 169 | |
| 170 | private static TextParseException |
| 171 | parseException(String str, String message) { |
| 172 | return new TextParseException("'" + str + "': " + message); |
| 173 | } |
| 174 | |
| 175 | private final void |
| 176 | appendFromString(String fullName, byte [] array, int start, int n) |
| 177 | throws TextParseException |
| 178 | { |
| 179 | try { |
| 180 | append(array, start, n); |
| 181 | } |
| 182 | catch (NameTooLongException e) { |
| 183 | throw parseException(fullName, "Name too long"); |
| 184 | } |
| 185 | } |
| 186 | |
| 187 | private final void |
| 188 | appendSafe(byte [] array, int start, int n) { |
| 189 | try { |
| 190 | append(array, start, n); |
| 191 | } |
| 192 | catch (NameTooLongException e) { |
| 193 | } |
| 194 | } |
| 195 | |
| 196 | /** |
| 197 | * Create a new name from a string and an origin. This does not automatically |
| 198 | * make the name absolute; it will be absolute if it has a trailing dot or an |
| 199 | * absolute origin is appended. |
| 200 | * @param s The string to be converted |
| 201 | * @param origin If the name is not absolute, the origin to be appended. |
| 202 | * @throws TextParseException The name is invalid. |
| 203 | */ |
| 204 | public |
| 205 | Name(String s, Name origin) throws TextParseException { |
| 206 | if (s.equals("")) |
| 207 | throw parseException(s, "empty name"); |
| 208 | else if (s.equals("@")) { |
| 209 | if (origin == null) |
| 210 | copy(empty, this); |
| 211 | else |
| 212 | copy(origin, this); |
| 213 | return; |
| 214 | } else if (s.equals(".")) { |
| 215 | copy(root, this); |
| 216 | return; |
| 217 | } |
| 218 | int labelstart = -1; |
| 219 | int pos = 1; |
| 220 | byte [] label = new byte[MAXLABEL + 1]; |
| 221 | boolean escaped = false; |
| 222 | int digits = 0; |
| 223 | int intval = 0; |
| 224 | boolean absolute = false; |
| 225 | for (int i = 0; i < s.length(); i++) { |
| 226 | byte b = (byte) s.charAt(i); |
| 227 | if (escaped) { |
| 228 | if (b >= '0' && b <= '9' && digits < 3) { |
| 229 | digits++; |
| 230 | intval *= 10; |
| 231 | intval += (b - '0'); |
| 232 | if (intval > 255) |
| 233 | throw parseException(s, "bad escape"); |
| 234 | if (digits < 3) |
| 235 | continue; |
| 236 | b = (byte) intval; |
| 237 | } |
| 238 | else if (digits > 0 && digits < 3) |
| 239 | throw parseException(s, "bad escape"); |
| 240 | if (pos > MAXLABEL) |
| 241 | throw parseException(s, "label too long"); |
| 242 | labelstart = pos; |
| 243 | label[pos++] = b; |
| 244 | escaped = false; |
| 245 | } else if (b == '\\') { |
| 246 | escaped = true; |
| 247 | digits = 0; |
| 248 | intval = 0; |
| 249 | } else if (b == '.') { |
| 250 | if (labelstart == -1) |
| 251 | throw parseException(s, "invalid empty label"); |
| 252 | label[0] = (byte)(pos - 1); |
| 253 | appendFromString(s, label, 0, 1); |
| 254 | labelstart = -1; |
| 255 | pos = 1; |
| 256 | } else { |
| 257 | if (labelstart == -1) |
| 258 | labelstart = i; |
| 259 | if (pos > MAXLABEL) |
| 260 | throw parseException(s, "label too long"); |
| 261 | label[pos++] = b; |
| 262 | } |
| 263 | } |
| 264 | if (digits > 0 && digits < 3) |
| 265 | throw parseException(s, "bad escape"); |
| 266 | if (escaped) |
| 267 | throw parseException(s, "bad escape"); |
| 268 | if (labelstart == -1) { |
| 269 | appendFromString(s, emptyLabel, 0, 1); |
| 270 | absolute = true; |
| 271 | } else { |
| 272 | label[0] = (byte)(pos - 1); |
| 273 | appendFromString(s, label, 0, 1); |
| 274 | } |
| 275 | if (origin != null && !absolute) |
| 276 | appendFromString(s, origin.name, 0, origin.getlabels()); |
| 277 | } |
| 278 | |
| 279 | /** |
| 280 | * Create a new name from a string. This does not automatically make the name |
| 281 | * absolute; it will be absolute if it has a trailing dot. |
| 282 | * @param s The string to be converted |
| 283 | * @throws TextParseException The name is invalid. |
| 284 | */ |
| 285 | public |
| 286 | Name(String s) throws TextParseException { |
| 287 | this(s, null); |
| 288 | } |
| 289 | |
| 290 | /** |
| 291 | * Create a new name from a string and an origin. This does not automatically |
| 292 | * make the name absolute; it will be absolute if it has a trailing dot or an |
| 293 | * absolute origin is appended. This is identical to the constructor, except |
| 294 | * that it will avoid creating new objects in some cases. |
| 295 | * @param s The string to be converted |
| 296 | * @param origin If the name is not absolute, the origin to be appended. |
| 297 | * @throws TextParseException The name is invalid. |
| 298 | */ |
| 299 | public static Name |
| 300 | fromString(String s, Name origin) throws TextParseException { |
| 301 | if (s.equals("@") && origin != null) |
| 302 | return origin; |
| 303 | else if (s.equals(".")) |
| 304 | return (root); |
| 305 | |
| 306 | return new Name(s, origin); |
| 307 | } |
| 308 | |
| 309 | /** |
| 310 | * Create a new name from a string. This does not automatically make the name |
| 311 | * absolute; it will be absolute if it has a trailing dot. This is identical |
| 312 | * to the constructor, except that it will avoid creating new objects in some |
| 313 | * cases. |
| 314 | * @param s The string to be converted |
| 315 | * @throws TextParseException The name is invalid. |
| 316 | */ |
| 317 | public static Name |
| 318 | fromString(String s) throws TextParseException { |
| 319 | return fromString(s, null); |
| 320 | } |
| 321 | |
| 322 | /** |
| 323 | * Create a new name from a constant string. This should only be used when |
| 324 | the name is known to be good - that is, when it is constant. |
| 325 | * @param s The string to be converted |
| 326 | * @throws IllegalArgumentException The name is invalid. |
| 327 | */ |
| 328 | public static Name |
| 329 | fromConstantString(String s) { |
| 330 | try { |
| 331 | return fromString(s, null); |
| 332 | } |
| 333 | catch (TextParseException e) { |
| 334 | throw new IllegalArgumentException("Invalid name '" + s + "'"); |
| 335 | } |
| 336 | } |
| 337 | |
| 338 | /** |
| 339 | * Create a new name from DNS a wire format message |
| 340 | * @param in A stream containing the DNS message which is currently |
| 341 | * positioned at the start of the name to be read. |
| 342 | */ |
| 343 | public |
| 344 | Name(DNSInput in) throws WireParseException { |
| 345 | int len, pos; |
| 346 | boolean done = false; |
| 347 | byte [] label = new byte[MAXLABEL + 1]; |
| 348 | boolean savedState = false; |
| 349 | |
| 350 | while (!done) { |
| 351 | len = in.readU8(); |
| 352 | switch (len & LABEL_MASK) { |
| 353 | case LABEL_NORMAL: |
| 354 | if (getlabels() >= MAXLABELS) |
| 355 | throw new WireParseException("too many labels"); |
| 356 | if (len == 0) { |
| 357 | append(emptyLabel, 0, 1); |
| 358 | done = true; |
| 359 | } else { |
| 360 | label[0] = (byte)len; |
| 361 | in.readByteArray(label, 1, len); |
| 362 | append(label, 0, 1); |
| 363 | } |
| 364 | break; |
| 365 | case LABEL_COMPRESSION: |
| 366 | pos = in.readU8(); |
| 367 | pos += ((len & ~LABEL_MASK) << 8); |
| 368 | if (Options.check("verbosecompression")) |
| 369 | System.err.println("currently " + in.current() + |
| 370 | ", pointer to " + pos); |
| 371 | |
| 372 | if (pos >= in.current() - 2) |
| 373 | throw new WireParseException("bad compression"); |
| 374 | if (!savedState) { |
| 375 | in.save(); |
| 376 | savedState = true; |
| 377 | } |
| 378 | in.jump(pos); |
| 379 | if (Options.check("verbosecompression")) |
| 380 | System.err.println("current name '" + this + |
| 381 | "', seeking to " + pos); |
| 382 | break; |
| 383 | default: |
| 384 | throw new WireParseException("bad label type"); |
| 385 | } |
| 386 | } |
| 387 | if (savedState) { |
| 388 | in.restore(); |
| 389 | } |
| 390 | } |
| 391 | |
| 392 | /** |
| 393 | * Create a new name from DNS wire format |
| 394 | * @param b A byte array containing the wire format of the name. |
| 395 | */ |
| 396 | public |
| 397 | Name(byte [] b) throws IOException { |
| 398 | this(new DNSInput(b)); |
| 399 | } |
| 400 | |
| 401 | /** |
| 402 | * Create a new name by removing labels from the beginning of an existing Name |
| 403 | * @param src An existing Name |
| 404 | * @param n The number of labels to remove from the beginning in the copy |
| 405 | */ |
| 406 | public |
| 407 | Name(Name src, int n) { |
| 408 | int slabels = src.labels(); |
| 409 | if (n > slabels) |
| 410 | throw new IllegalArgumentException("attempted to remove too " + |
| 411 | "many labels"); |
| 412 | name = src.name; |
| 413 | setlabels(slabels - n); |
| 414 | for (int i = 0; i < MAXOFFSETS && i < slabels - n; i++) |
| 415 | setoffset(i, src.offset(i + n)); |
| 416 | } |
| 417 | |
| 418 | /** |
| 419 | * Creates a new name by concatenating two existing names. |
| 420 | * @param prefix The prefix name. |
| 421 | * @param suffix The suffix name. |
| 422 | * @return The concatenated name. |
| 423 | * @throws NameTooLongException The name is too long. |
| 424 | */ |
| 425 | public static Name |
| 426 | concatenate(Name prefix, Name suffix) throws NameTooLongException { |
| 427 | if (prefix.isAbsolute()) |
| 428 | return (prefix); |
| 429 | Name newname = new Name(); |
| 430 | copy(prefix, newname); |
| 431 | newname.append(suffix.name, suffix.offset(0), suffix.getlabels()); |
| 432 | return newname; |
| 433 | } |
| 434 | |
| 435 | /** |
| 436 | * If this name is a subdomain of origin, return a new name relative to |
| 437 | * origin with the same value. Otherwise, return the existing name. |
| 438 | * @param origin The origin to remove. |
| 439 | * @return The possibly relativized name. |
| 440 | */ |
| 441 | public Name |
| 442 | relativize(Name origin) { |
| 443 | if (origin == null || !subdomain(origin)) |
| 444 | return this; |
| 445 | Name newname = new Name(); |
| 446 | copy(this, newname); |
| 447 | int length = length() - origin.length(); |
| 448 | int labels = newname.labels() - origin.labels(); |
| 449 | newname.setlabels(labels); |
| 450 | newname.name = new byte[length]; |
| 451 | System.arraycopy(name, offset(0), newname.name, 0, length); |
| 452 | return newname; |
| 453 | } |
| 454 | |
| 455 | /** |
| 456 | * Generates a new Name with the first n labels replaced by a wildcard |
| 457 | * @return The wildcard name |
| 458 | */ |
| 459 | public Name |
| 460 | wild(int n) { |
| 461 | if (n < 1) |
| 462 | throw new IllegalArgumentException("must replace 1 or more " + |
| 463 | "labels"); |
| 464 | try { |
| 465 | Name newname = new Name(); |
| 466 | copy(wild, newname); |
| 467 | newname.append(name, offset(n), getlabels() - n); |
| 468 | return newname; |
| 469 | } |
| 470 | catch (NameTooLongException e) { |
| 471 | throw new IllegalStateException |
| 472 | ("Name.wild: concatenate failed"); |
| 473 | } |
| 474 | } |
| 475 | |
| 476 | /** |
| 477 | * Generates a new Name to be used when following a DNAME. |
| 478 | * @param dname The DNAME record to follow. |
| 479 | * @return The constructed name. |
| 480 | * @throws NameTooLongException The resulting name is too long. |
| 481 | */ |
| 482 | public Name |
| 483 | fromDNAME(DNAMERecord dname) throws NameTooLongException { |
| 484 | Name dnameowner = dname.getName(); |
| 485 | Name dnametarget = dname.getTarget(); |
| 486 | if (!subdomain(dnameowner)) |
| 487 | return null; |
| 488 | |
| 489 | int plabels = labels() - dnameowner.labels(); |
| 490 | int plength = length() - dnameowner.length(); |
| 491 | int pstart = offset(0); |
| 492 | |
| 493 | int dlabels = dnametarget.labels(); |
| 494 | int dlength = dnametarget.length(); |
| 495 | |
| 496 | if (plength + dlength > MAXNAME) |
| 497 | throw new NameTooLongException(); |
| 498 | |
| 499 | Name newname = new Name(); |
| 500 | newname.setlabels(plabels + dlabels); |
| 501 | newname.name = new byte[plength + dlength]; |
| 502 | System.arraycopy(name, pstart, newname.name, 0, plength); |
| 503 | System.arraycopy(dnametarget.name, 0, newname.name, plength, dlength); |
| 504 | |
| 505 | for (int i = 0, pos = 0; i < MAXOFFSETS && i < plabels + dlabels; i++) { |
| 506 | newname.setoffset(i, pos); |
| 507 | pos += (newname.name[pos] + 1); |
| 508 | } |
| 509 | return newname; |
| 510 | } |
| 511 | |
| 512 | /** |
| 513 | * Is this name a wildcard? |
| 514 | */ |
| 515 | public boolean |
| 516 | isWild() { |
| 517 | if (labels() == 0) |
| 518 | return false; |
| 519 | return (name[0] == (byte)1 && name[1] == (byte)'*'); |
| 520 | } |
| 521 | |
| 522 | /** |
| 523 | * Is this name absolute? |
| 524 | */ |
| 525 | public boolean |
| 526 | isAbsolute() { |
| 527 | if (labels() == 0) |
| 528 | return false; |
| 529 | return (name[name.length - 1] == 0); |
| 530 | } |
| 531 | |
| 532 | /** |
| 533 | * The length of the name. |
| 534 | */ |
| 535 | public short |
| 536 | length() { |
| 537 | if (getlabels() == 0) |
| 538 | return 0; |
| 539 | return (short)(name.length - offset(0)); |
| 540 | } |
| 541 | |
| 542 | /** |
| 543 | * The number of labels in the name. |
| 544 | */ |
| 545 | public int |
| 546 | labels() { |
| 547 | return getlabels(); |
| 548 | } |
| 549 | |
| 550 | /** |
| 551 | * Is the current Name a subdomain of the specified name? |
| 552 | */ |
| 553 | public boolean |
| 554 | subdomain(Name domain) { |
| 555 | int labels = labels(); |
| 556 | int dlabels = domain.labels(); |
| 557 | if (dlabels > labels) |
| 558 | return false; |
| 559 | if (dlabels == labels) |
| 560 | return equals(domain); |
| 561 | return domain.equals(name, offset(labels - dlabels)); |
| 562 | } |
| 563 | |
| 564 | private String |
| 565 | byteString(byte [] array, int pos) { |
| 566 | StringBuffer sb = new StringBuffer(); |
| 567 | int len = array[pos++]; |
| 568 | for (int i = pos; i < pos + len; i++) { |
| 569 | int b = array[i] & 0xFF; |
| 570 | if (b <= 0x20 || b >= 0x7f) { |
| 571 | sb.append('\\'); |
| 572 | sb.append(byteFormat.format(b)); |
| 573 | } |
| 574 | else if (b == '"' || b == '(' || b == ')' || b == '.' || |
| 575 | b == ';' || b == '\\' || b == '@' || b == '$') |
| 576 | { |
| 577 | sb.append('\\'); |
| 578 | sb.append((char)b); |
| 579 | } |
| 580 | else |
| 581 | sb.append((char)b); |
| 582 | } |
| 583 | return sb.toString(); |
| 584 | } |
| 585 | |
| 586 | /** |
| 587 | * Convert a Name to a String |
| 588 | * @return The representation of this name as a (printable) String. |
| 589 | */ |
| 590 | public String |
| 591 | toString() { |
| 592 | int labels = labels(); |
| 593 | if (labels == 0) |
| 594 | return "@"; |
| 595 | else if (labels == 1 && name[offset(0)] == 0) |
| 596 | return "."; |
| 597 | StringBuffer sb = new StringBuffer(); |
| 598 | for (int i = 0, pos = offset(0); i < labels; i++) { |
| 599 | int len = name[pos]; |
| 600 | if (len > MAXLABEL) |
| 601 | throw new IllegalStateException("invalid label"); |
| 602 | if (len == 0) |
| 603 | break; |
| 604 | sb.append(byteString(name, pos)); |
| 605 | sb.append('.'); |
| 606 | pos += (1 + len); |
| 607 | } |
| 608 | if (!isAbsolute()) |
| 609 | sb.deleteCharAt(sb.length() - 1); |
| 610 | return sb.toString(); |
| 611 | } |
| 612 | |
| 613 | /** |
| 614 | * Retrieve the nth label of a Name. This makes a copy of the label; changing |
| 615 | * this does not change the Name. |
| 616 | * @param n The label to be retrieved. The first label is 0. |
| 617 | */ |
| 618 | public byte [] |
| 619 | getLabel(int n) { |
| 620 | int pos = offset(n); |
| 621 | byte len = (byte)(name[pos] + 1); |
| 622 | byte [] label = new byte[len]; |
| 623 | System.arraycopy(name, pos, label, 0, len); |
| 624 | return label; |
| 625 | } |
| 626 | |
| 627 | /** |
| 628 | * Convert the nth label in a Name to a String |
| 629 | * @param n The label to be converted to a (printable) String. The first |
| 630 | * label is 0. |
| 631 | */ |
| 632 | public String |
| 633 | getLabelString(int n) { |
| 634 | int pos = offset(n); |
| 635 | return byteString(name, pos); |
| 636 | } |
| 637 | |
| 638 | /** |
| 639 | * Emit a Name in DNS wire format |
| 640 | * @param out The output stream containing the DNS message. |
| 641 | * @param c The compression context, or null of no compression is desired. |
| 642 | * @throws IllegalArgumentException The name is not absolute. |
| 643 | */ |
| 644 | public void |
| 645 | toWire(DNSOutput out, Compression c) { |
| 646 | if (!isAbsolute()) |
| 647 | throw new IllegalArgumentException("toWire() called on " + |
| 648 | "non-absolute name"); |
| 649 | |
| 650 | int labels = labels(); |
| 651 | for (int i = 0; i < labels - 1; i++) { |
| 652 | Name tname; |
| 653 | if (i == 0) |
| 654 | tname = this; |
| 655 | else |
| 656 | tname = new Name(this, i); |
| 657 | int pos = -1; |
| 658 | if (c != null) |
| 659 | pos = c.get(tname); |
| 660 | if (pos >= 0) { |
| 661 | pos |= (LABEL_MASK << 8); |
| 662 | out.writeU16(pos); |
| 663 | return; |
| 664 | } else { |
| 665 | if (c != null) |
| 666 | c.add(out.current(), tname); |
| 667 | int off = offset(i); |
| 668 | out.writeByteArray(name, off, name[off] + 1); |
| 669 | } |
| 670 | } |
| 671 | out.writeU8(0); |
| 672 | } |
| 673 | |
| 674 | /** |
| 675 | * Emit a Name in DNS wire format |
| 676 | * @throws IllegalArgumentException The name is not absolute. |
| 677 | */ |
| 678 | public byte [] |
| 679 | toWire() { |
| 680 | DNSOutput out = new DNSOutput(); |
| 681 | toWire(out, null); |
| 682 | return out.toByteArray(); |
| 683 | } |
| 684 | |
| 685 | /** |
| 686 | * Emit a Name in canonical DNS wire format (all lowercase) |
| 687 | * @param out The output stream to which the message is written. |
| 688 | */ |
| 689 | public void |
| 690 | toWireCanonical(DNSOutput out) { |
| 691 | byte [] b = toWireCanonical(); |
| 692 | out.writeByteArray(b); |
| 693 | } |
| 694 | |
| 695 | /** |
| 696 | * Emit a Name in canonical DNS wire format (all lowercase) |
| 697 | * @return The canonical form of the name. |
| 698 | */ |
| 699 | public byte [] |
| 700 | toWireCanonical() { |
| 701 | int labels = labels(); |
| 702 | if (labels == 0) |
| 703 | return (new byte[0]); |
| 704 | byte [] b = new byte[name.length - offset(0)]; |
| 705 | for (int i = 0, spos = offset(0), dpos = 0; i < labels; i++) { |
| 706 | int len = name[spos]; |
| 707 | if (len > MAXLABEL) |
| 708 | throw new IllegalStateException("invalid label"); |
| 709 | b[dpos++] = name[spos++]; |
| 710 | for (int j = 0; j < len; j++) |
| 711 | b[dpos++] = lowercase[(name[spos++] & 0xFF)]; |
| 712 | } |
| 713 | return b; |
| 714 | } |
| 715 | |
| 716 | /** |
| 717 | * Emit a Name in DNS wire format |
| 718 | * @param out The output stream containing the DNS message. |
| 719 | * @param c The compression context, or null of no compression is desired. |
| 720 | * @param canonical If true, emit the name in canonicalized form |
| 721 | * (all lowercase). |
| 722 | * @throws IllegalArgumentException The name is not absolute. |
| 723 | */ |
| 724 | public void |
| 725 | toWire(DNSOutput out, Compression c, boolean canonical) { |
| 726 | if (canonical) |
| 727 | toWireCanonical(out); |
| 728 | else |
| 729 | toWire(out, c); |
| 730 | } |
| 731 | |
| 732 | private final boolean |
| 733 | equals(byte [] b, int bpos) { |
| 734 | int labels = labels(); |
| 735 | for (int i = 0, pos = offset(0); i < labels; i++) { |
| 736 | if (name[pos] != b[bpos]) |
| 737 | return false; |
| 738 | int len = name[pos++]; |
| 739 | bpos++; |
| 740 | if (len > MAXLABEL) |
| 741 | throw new IllegalStateException("invalid label"); |
| 742 | for (int j = 0; j < len; j++) |
| 743 | if (lowercase[(name[pos++] & 0xFF)] != |
| 744 | lowercase[(b[bpos++] & 0xFF)]) |
| 745 | return false; |
| 746 | } |
| 747 | return true; |
| 748 | } |
| 749 | |
| 750 | /** |
| 751 | * Are these two Names equivalent? |
| 752 | */ |
| 753 | public boolean |
| 754 | equals(Object arg) { |
| 755 | if (arg == this) |
| 756 | return true; |
| 757 | if (arg == null || !(arg instanceof Name)) |
| 758 | return false; |
| 759 | Name d = (Name) arg; |
| 760 | if (d.hashcode == 0) |
| 761 | d.hashCode(); |
| 762 | if (hashcode == 0) |
| 763 | hashCode(); |
| 764 | if (d.hashcode != hashcode) |
| 765 | return false; |
| 766 | if (d.labels() != labels()) |
| 767 | return false; |
| 768 | return equals(d.name, d.offset(0)); |
| 769 | } |
| 770 | |
| 771 | /** |
| 772 | * Computes a hashcode based on the value |
| 773 | */ |
| 774 | public int |
| 775 | hashCode() { |
| 776 | if (hashcode != 0) |
| 777 | return (hashcode); |
| 778 | int code = 0; |
| 779 | for (int i = offset(0); i < name.length; i++) |
| 780 | code += ((code << 3) + lowercase[(name[i] & 0xFF)]); |
| 781 | hashcode = code; |
| 782 | return hashcode; |
| 783 | } |
| 784 | |
| 785 | /** |
| 786 | * Compares this Name to another Object. |
| 787 | * @param o The Object to be compared. |
| 788 | * @return The value 0 if the argument is a name equivalent to this name; |
| 789 | * a value less than 0 if the argument is less than this name in the canonical |
| 790 | * ordering, and a value greater than 0 if the argument is greater than this |
| 791 | * name in the canonical ordering. |
| 792 | * @throws ClassCastException if the argument is not a Name. |
| 793 | */ |
| 794 | public int |
| 795 | compareTo(Object o) { |
| 796 | Name arg = (Name) o; |
| 797 | |
| 798 | if (this == arg) |
| 799 | return (0); |
| 800 | |
| 801 | int labels = labels(); |
| 802 | int alabels = arg.labels(); |
| 803 | int compares = labels > alabels ? alabels : labels; |
| 804 | |
| 805 | for (int i = 1; i <= compares; i++) { |
| 806 | int start = offset(labels - i); |
| 807 | int astart = arg.offset(alabels - i); |
| 808 | int length = name[start]; |
| 809 | int alength = arg.name[astart]; |
| 810 | for (int j = 0; j < length && j < alength; j++) { |
| 811 | int n = lowercase[(name[j + start + 1]) & 0xFF] - |
| 812 | lowercase[(arg.name[j + astart + 1]) & 0xFF]; |
| 813 | if (n != 0) |
| 814 | return (n); |
| 815 | } |
| 816 | if (length != alength) |
| 817 | return (length - alength); |
| 818 | } |
| 819 | return (labels - alabels); |
| 820 | } |
| 821 | |
| 822 | } |