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.util.*; |
| 6 | import java.io.*; |
| 7 | |
| 8 | /** |
| 9 | * A DNS Message. A message is the basic unit of communication between |
| 10 | * the client and server of a DNS operation. A message consists of a Header |
| 11 | * and 4 message sections. |
| 12 | * @see Resolver |
| 13 | * @see Header |
| 14 | * @see Section |
| 15 | * |
| 16 | * @author Brian Wellington |
| 17 | */ |
| 18 | |
| 19 | public class Message implements Cloneable { |
| 20 | |
| 21 | /** The maximum length of a message in wire format. */ |
| 22 | public static final int MAXLENGTH = 65535; |
| 23 | |
| 24 | private Header header; |
| 25 | private List [] sections; |
| 26 | private int size; |
| 27 | private TSIG tsigkey; |
| 28 | private TSIGRecord querytsig; |
| 29 | private int tsigerror; |
| 30 | |
| 31 | int tsigstart; |
| 32 | int tsigState; |
| 33 | int sig0start; |
| 34 | |
| 35 | /* The message was not signed */ |
| 36 | static final int TSIG_UNSIGNED = 0; |
| 37 | |
| 38 | /* The message was signed and verification succeeded */ |
| 39 | static final int TSIG_VERIFIED = 1; |
| 40 | |
| 41 | /* The message was an unsigned message in multiple-message response */ |
| 42 | static final int TSIG_INTERMEDIATE = 2; |
| 43 | |
| 44 | /* The message was signed and no verification was attempted. */ |
| 45 | static final int TSIG_SIGNED = 3; |
| 46 | |
| 47 | /* |
| 48 | * The message was signed and verification failed, or was not signed |
| 49 | * when it should have been. |
| 50 | */ |
| 51 | static final int TSIG_FAILED = 4; |
| 52 | |
| 53 | private static Record [] emptyRecordArray = new Record[0]; |
| 54 | private static RRset [] emptyRRsetArray = new RRset[0]; |
| 55 | |
| 56 | private |
| 57 | Message(Header header) { |
| 58 | sections = new List[4]; |
| 59 | this.header = header; |
| 60 | } |
| 61 | |
| 62 | /** Creates a new Message with the specified Message ID */ |
| 63 | public |
| 64 | Message(int id) { |
| 65 | this(new Header(id)); |
| 66 | } |
| 67 | |
| 68 | /** Creates a new Message with a random Message ID */ |
| 69 | public |
| 70 | Message() { |
| 71 | this(new Header()); |
| 72 | } |
| 73 | |
| 74 | /** |
| 75 | * Creates a new Message with a random Message ID suitable for sending as a |
| 76 | * query. |
| 77 | * @param r A record containing the question |
| 78 | */ |
| 79 | public static Message |
| 80 | newQuery(Record r) { |
| 81 | Message m = new Message(); |
| 82 | m.header.setOpcode(Opcode.QUERY); |
| 83 | m.header.setFlag(Flags.RD); |
| 84 | m.addRecord(r, Section.QUESTION); |
| 85 | return m; |
| 86 | } |
| 87 | |
| 88 | /** |
| 89 | * Creates a new Message to contain a dynamic update. A random Message ID |
| 90 | * and the zone are filled in. |
| 91 | * @param zone The zone to be updated |
| 92 | */ |
| 93 | public static Message |
| 94 | newUpdate(Name zone) { |
| 95 | return new Update(zone); |
| 96 | } |
| 97 | |
| 98 | Message(DNSInput in) throws IOException { |
| 99 | this(new Header(in)); |
| 100 | boolean isUpdate = (header.getOpcode() == Opcode.UPDATE); |
| 101 | boolean truncated = header.getFlag(Flags.TC); |
| 102 | try { |
| 103 | for (int i = 0; i < 4; i++) { |
| 104 | int count = header.getCount(i); |
| 105 | if (count > 0) |
| 106 | sections[i] = new ArrayList(count); |
| 107 | for (int j = 0; j < count; j++) { |
| 108 | int pos = in.current(); |
| 109 | Record rec = Record.fromWire(in, i, isUpdate); |
| 110 | sections[i].add(rec); |
| 111 | if (i == Section.ADDITIONAL) { |
| 112 | if (rec.getType() == Type.TSIG) |
| 113 | tsigstart = pos; |
| 114 | if (rec.getType() == Type.SIG) { |
| 115 | SIGRecord sig = (SIGRecord) rec; |
| 116 | if (sig.getTypeCovered() == 0) |
| 117 | sig0start = pos; |
| 118 | } |
| 119 | } |
| 120 | } |
| 121 | } |
| 122 | } catch (WireParseException e) { |
| 123 | if (!truncated) |
| 124 | throw e; |
| 125 | } |
| 126 | size = in.current(); |
| 127 | } |
| 128 | |
| 129 | /** |
| 130 | * Creates a new Message from its DNS wire format representation |
| 131 | * @param b A byte array containing the DNS Message. |
| 132 | */ |
| 133 | public |
| 134 | Message(byte [] b) throws IOException { |
| 135 | this(new DNSInput(b)); |
| 136 | } |
| 137 | |
| 138 | /** |
| 139 | * Replaces the Header with a new one. |
| 140 | * @see Header |
| 141 | */ |
| 142 | public void |
| 143 | setHeader(Header h) { |
| 144 | header = h; |
| 145 | } |
| 146 | |
| 147 | /** |
| 148 | * Retrieves the Header. |
| 149 | * @see Header |
| 150 | */ |
| 151 | public Header |
| 152 | getHeader() { |
| 153 | return header; |
| 154 | } |
| 155 | |
| 156 | /** |
| 157 | * Adds a record to a section of the Message, and adjusts the header. |
| 158 | * @see Record |
| 159 | * @see Section |
| 160 | */ |
| 161 | public void |
| 162 | addRecord(Record r, int section) { |
| 163 | if (sections[section] == null) |
| 164 | sections[section] = new LinkedList(); |
| 165 | header.incCount(section); |
| 166 | sections[section].add(r); |
| 167 | } |
| 168 | |
| 169 | /** |
| 170 | * Removes a record from a section of the Message, and adjusts the header. |
| 171 | * @see Record |
| 172 | * @see Section |
| 173 | */ |
| 174 | public boolean |
| 175 | removeRecord(Record r, int section) { |
| 176 | if (sections[section] != null && sections[section].remove(r)) { |
| 177 | header.decCount(section); |
| 178 | return true; |
| 179 | } |
| 180 | else |
| 181 | return false; |
| 182 | } |
| 183 | |
| 184 | /** |
| 185 | * Removes all records from a section of the Message, and adjusts the header. |
| 186 | * @see Record |
| 187 | * @see Section |
| 188 | */ |
| 189 | public void |
| 190 | removeAllRecords(int section) { |
| 191 | sections[section] = null; |
| 192 | header.setCount(section, 0); |
| 193 | } |
| 194 | |
| 195 | /** |
| 196 | * Determines if the given record is already present in the given section. |
| 197 | * @see Record |
| 198 | * @see Section |
| 199 | */ |
| 200 | public boolean |
| 201 | findRecord(Record r, int section) { |
| 202 | return (sections[section] != null && sections[section].contains(r)); |
| 203 | } |
| 204 | |
| 205 | /** |
| 206 | * Determines if the given record is already present in any section. |
| 207 | * @see Record |
| 208 | * @see Section |
| 209 | */ |
| 210 | public boolean |
| 211 | findRecord(Record r) { |
| 212 | for (int i = Section.ANSWER; i <= Section.ADDITIONAL; i++) |
| 213 | if (sections[i] != null && sections[i].contains(r)) |
| 214 | return true; |
| 215 | return false; |
| 216 | } |
| 217 | |
| 218 | /** |
| 219 | * Determines if an RRset with the given name and type is already |
| 220 | * present in the given section. |
| 221 | * @see RRset |
| 222 | * @see Section |
| 223 | */ |
| 224 | public boolean |
| 225 | findRRset(Name name, int type, int section) { |
| 226 | if (sections[section] == null) |
| 227 | return false; |
| 228 | for (int i = 0; i < sections[section].size(); i++) { |
| 229 | Record r = (Record) sections[section].get(i); |
| 230 | if (r.getType() == type && name.equals(r.getName())) |
| 231 | return true; |
| 232 | } |
| 233 | return false; |
| 234 | } |
| 235 | |
| 236 | /** |
| 237 | * Determines if an RRset with the given name and type is already |
| 238 | * present in any section. |
| 239 | * @see RRset |
| 240 | * @see Section |
| 241 | */ |
| 242 | public boolean |
| 243 | findRRset(Name name, int type) { |
| 244 | return (findRRset(name, type, Section.ANSWER) || |
| 245 | findRRset(name, type, Section.AUTHORITY) || |
| 246 | findRRset(name, type, Section.ADDITIONAL)); |
| 247 | } |
| 248 | |
| 249 | /** |
| 250 | * Returns the first record in the QUESTION section. |
| 251 | * @see Record |
| 252 | * @see Section |
| 253 | */ |
| 254 | public Record |
| 255 | getQuestion() { |
| 256 | List l = sections[Section.QUESTION]; |
| 257 | if (l == null || l.size() == 0) |
| 258 | return null; |
| 259 | return (Record) l.get(0); |
| 260 | } |
| 261 | |
| 262 | /** |
| 263 | * Returns the TSIG record from the ADDITIONAL section, if one is present. |
| 264 | * @see TSIGRecord |
| 265 | * @see TSIG |
| 266 | * @see Section |
| 267 | */ |
| 268 | public TSIGRecord |
| 269 | getTSIG() { |
| 270 | int count = header.getCount(Section.ADDITIONAL); |
| 271 | if (count == 0) |
| 272 | return null; |
| 273 | List l = sections[Section.ADDITIONAL]; |
| 274 | Record rec = (Record) l.get(count - 1); |
| 275 | if (rec.type != Type.TSIG) |
| 276 | return null; |
| 277 | return (TSIGRecord) rec; |
| 278 | } |
| 279 | |
| 280 | /** |
| 281 | * Was this message signed by a TSIG? |
| 282 | * @see TSIG |
| 283 | */ |
| 284 | public boolean |
| 285 | isSigned() { |
| 286 | return (tsigState == TSIG_SIGNED || |
| 287 | tsigState == TSIG_VERIFIED || |
| 288 | tsigState == TSIG_FAILED); |
| 289 | } |
| 290 | |
| 291 | /** |
| 292 | * If this message was signed by a TSIG, was the TSIG verified? |
| 293 | * @see TSIG |
| 294 | */ |
| 295 | public boolean |
| 296 | isVerified() { |
| 297 | return (tsigState == TSIG_VERIFIED); |
| 298 | } |
| 299 | |
| 300 | /** |
| 301 | * Returns the OPT record from the ADDITIONAL section, if one is present. |
| 302 | * @see OPTRecord |
| 303 | * @see Section |
| 304 | */ |
| 305 | public OPTRecord |
| 306 | getOPT() { |
| 307 | Record [] additional = getSectionArray(Section.ADDITIONAL); |
| 308 | for (int i = 0; i < additional.length; i++) |
| 309 | if (additional[i] instanceof OPTRecord) |
| 310 | return (OPTRecord) additional[i]; |
| 311 | return null; |
| 312 | } |
| 313 | |
| 314 | /** |
| 315 | * Returns the message's rcode (error code). This incorporates the EDNS |
| 316 | * extended rcode. |
| 317 | */ |
| 318 | public int |
| 319 | getRcode() { |
| 320 | int rcode = header.getRcode(); |
| 321 | OPTRecord opt = getOPT(); |
| 322 | if (opt != null) |
| 323 | rcode += (opt.getExtendedRcode() << 4); |
| 324 | return rcode; |
| 325 | } |
| 326 | |
| 327 | /** |
| 328 | * Returns an array containing all records in the given section, or an |
| 329 | * empty array if the section is empty. |
| 330 | * @see Record |
| 331 | * @see Section |
| 332 | */ |
| 333 | public Record [] |
| 334 | getSectionArray(int section) { |
| 335 | if (sections[section] == null) |
| 336 | return emptyRecordArray; |
| 337 | List l = sections[section]; |
| 338 | return (Record []) l.toArray(new Record[l.size()]); |
| 339 | } |
| 340 | |
| 341 | private static boolean |
| 342 | sameSet(Record r1, Record r2) { |
| 343 | return (r1.getRRsetType() == r2.getRRsetType() && |
| 344 | r1.getDClass() == r2.getDClass() && |
| 345 | r1.getName().equals(r2.getName())); |
| 346 | } |
| 347 | |
| 348 | /** |
| 349 | * Returns an array containing all records in the given section grouped into |
| 350 | * RRsets. |
| 351 | * @see RRset |
| 352 | * @see Section |
| 353 | */ |
| 354 | public RRset [] |
| 355 | getSectionRRsets(int section) { |
| 356 | if (sections[section] == null) |
| 357 | return emptyRRsetArray; |
| 358 | List sets = new LinkedList(); |
| 359 | Record [] recs = getSectionArray(section); |
| 360 | Set hash = new HashSet(); |
| 361 | for (int i = 0; i < recs.length; i++) { |
| 362 | Name name = recs[i].getName(); |
| 363 | boolean newset = true; |
| 364 | if (hash.contains(name)) { |
| 365 | for (int j = sets.size() - 1; j >= 0; j--) { |
| 366 | RRset set = (RRset) sets.get(j); |
| 367 | if (set.getType() == recs[i].getRRsetType() && |
| 368 | set.getDClass() == recs[i].getDClass() && |
| 369 | set.getName().equals(name)) |
| 370 | { |
| 371 | set.addRR(recs[i]); |
| 372 | newset = false; |
| 373 | break; |
| 374 | } |
| 375 | } |
| 376 | } |
| 377 | if (newset) { |
| 378 | RRset set = new RRset(recs[i]); |
| 379 | sets.add(set); |
| 380 | hash.add(name); |
| 381 | } |
| 382 | } |
| 383 | return (RRset []) sets.toArray(new RRset[sets.size()]); |
| 384 | } |
| 385 | |
| 386 | void |
| 387 | toWire(DNSOutput out) { |
| 388 | header.toWire(out); |
| 389 | Compression c = new Compression(); |
| 390 | for (int i = 0; i < 4; i++) { |
| 391 | if (sections[i] == null) |
| 392 | continue; |
| 393 | for (int j = 0; j < sections[i].size(); j++) { |
| 394 | Record rec = (Record)sections[i].get(j); |
| 395 | rec.toWire(out, i, c); |
| 396 | } |
| 397 | } |
| 398 | } |
| 399 | |
| 400 | /* Returns the number of records not successfully rendered. */ |
| 401 | private int |
| 402 | sectionToWire(DNSOutput out, int section, Compression c, |
| 403 | int maxLength) |
| 404 | { |
| 405 | int n = sections[section].size(); |
| 406 | int pos = out.current(); |
| 407 | int rendered = 0; |
| 408 | Record lastrec = null; |
| 409 | |
| 410 | for (int i = 0; i < n; i++) { |
| 411 | Record rec = (Record)sections[section].get(i); |
| 412 | if (lastrec != null && !sameSet(rec, lastrec)) { |
| 413 | pos = out.current(); |
| 414 | rendered = i; |
| 415 | } |
| 416 | lastrec = rec; |
| 417 | rec.toWire(out, section, c); |
| 418 | if (out.current() > maxLength) { |
| 419 | out.jump(pos); |
| 420 | return n - rendered; |
| 421 | } |
| 422 | } |
| 423 | return 0; |
| 424 | } |
| 425 | |
| 426 | /* Returns true if the message could be rendered. */ |
| 427 | private boolean |
| 428 | toWire(DNSOutput out, int maxLength) { |
| 429 | if (maxLength < Header.LENGTH) |
| 430 | return false; |
| 431 | |
| 432 | Header newheader = null; |
| 433 | |
| 434 | int tempMaxLength = maxLength; |
| 435 | if (tsigkey != null) |
| 436 | tempMaxLength -= tsigkey.recordLength(); |
| 437 | |
| 438 | int startpos = out.current(); |
| 439 | header.toWire(out); |
| 440 | Compression c = new Compression(); |
| 441 | for (int i = 0; i < 4; i++) { |
| 442 | int skipped; |
| 443 | if (sections[i] == null) |
| 444 | continue; |
| 445 | skipped = sectionToWire(out, i, c, tempMaxLength); |
| 446 | if (skipped != 0) { |
| 447 | if (newheader == null) |
| 448 | newheader = (Header) header.clone(); |
| 449 | if (i != Section.ADDITIONAL) |
| 450 | newheader.setFlag(Flags.TC); |
| 451 | int count = newheader.getCount(i); |
| 452 | newheader.setCount(i, count - skipped); |
| 453 | for (int j = i + 1; j < 4; j++) |
| 454 | newheader.setCount(j, 0); |
| 455 | |
| 456 | out.save(); |
| 457 | out.jump(startpos); |
| 458 | newheader.toWire(out); |
| 459 | out.restore(); |
| 460 | break; |
| 461 | } |
| 462 | } |
| 463 | |
| 464 | if (tsigkey != null) { |
| 465 | TSIGRecord tsigrec = tsigkey.generate(this, out.toByteArray(), |
| 466 | tsigerror, querytsig); |
| 467 | |
| 468 | if (newheader == null) |
| 469 | newheader = (Header) header.clone(); |
| 470 | tsigrec.toWire(out, Section.ADDITIONAL, c); |
| 471 | newheader.incCount(Section.ADDITIONAL); |
| 472 | |
| 473 | out.save(); |
| 474 | out.jump(startpos); |
| 475 | newheader.toWire(out); |
| 476 | out.restore(); |
| 477 | } |
| 478 | |
| 479 | return true; |
| 480 | } |
| 481 | |
| 482 | /** |
| 483 | * Returns an array containing the wire format representation of the Message. |
| 484 | */ |
| 485 | public byte [] |
| 486 | toWire() { |
| 487 | DNSOutput out = new DNSOutput(); |
| 488 | toWire(out); |
| 489 | size = out.current(); |
| 490 | return out.toByteArray(); |
| 491 | } |
| 492 | |
| 493 | /** |
| 494 | * Returns an array containing the wire format representation of the Message |
| 495 | * with the specified maximum length. This will generate a truncated |
| 496 | * message (with the TC bit) if the message doesn't fit, and will also |
| 497 | * sign the message with the TSIG key set by a call to setTSIG(). This |
| 498 | * method may return null if the message could not be rendered at all; this |
| 499 | * could happen if maxLength is smaller than a DNS header, for example. |
| 500 | * @param maxLength The maximum length of the message. |
| 501 | * @return The wire format of the message, or null if the message could not be |
| 502 | * rendered into the specified length. |
| 503 | * @see Flags |
| 504 | * @see TSIG |
| 505 | */ |
| 506 | public byte [] |
| 507 | toWire(int maxLength) { |
| 508 | DNSOutput out = new DNSOutput(); |
| 509 | toWire(out, maxLength); |
| 510 | size = out.current(); |
| 511 | return out.toByteArray(); |
| 512 | } |
| 513 | |
| 514 | /** |
| 515 | * Sets the TSIG key and other necessary information to sign a message. |
| 516 | * @param key The TSIG key. |
| 517 | * @param error The value of the TSIG error field. |
| 518 | * @param querytsig If this is a response, the TSIG from the request. |
| 519 | */ |
| 520 | public void |
| 521 | setTSIG(TSIG key, int error, TSIGRecord querytsig) { |
| 522 | this.tsigkey = key; |
| 523 | this.tsigerror = error; |
| 524 | this.querytsig = querytsig; |
| 525 | } |
| 526 | |
| 527 | /** |
| 528 | * Returns the size of the message. Only valid if the message has been |
| 529 | * converted to or from wire format. |
| 530 | */ |
| 531 | public int |
| 532 | numBytes() { |
| 533 | return size; |
| 534 | } |
| 535 | |
| 536 | /** |
| 537 | * Converts the given section of the Message to a String. |
| 538 | * @see Section |
| 539 | */ |
| 540 | public String |
| 541 | sectionToString(int i) { |
| 542 | if (i > 3) |
| 543 | return null; |
| 544 | |
| 545 | StringBuffer sb = new StringBuffer(); |
| 546 | |
| 547 | Record [] records = getSectionArray(i); |
| 548 | for (int j = 0; j < records.length; j++) { |
| 549 | Record rec = records[j]; |
| 550 | if (i == Section.QUESTION) { |
| 551 | sb.append(";;\t" + rec.name); |
| 552 | sb.append(", type = " + Type.string(rec.type)); |
| 553 | sb.append(", class = " + DClass.string(rec.dclass)); |
| 554 | } |
| 555 | else |
| 556 | sb.append(rec); |
| 557 | sb.append("\n"); |
| 558 | } |
| 559 | return sb.toString(); |
| 560 | } |
| 561 | |
| 562 | /** |
| 563 | * Converts the Message to a String. |
| 564 | */ |
| 565 | public String |
| 566 | toString() { |
| 567 | StringBuffer sb = new StringBuffer(); |
| 568 | OPTRecord opt = getOPT(); |
| 569 | if (opt != null) |
| 570 | sb.append(header.toStringWithRcode(getRcode()) + "\n"); |
| 571 | else |
| 572 | sb.append(header + "\n"); |
| 573 | if (isSigned()) { |
| 574 | sb.append(";; TSIG "); |
| 575 | if (isVerified()) |
| 576 | sb.append("ok"); |
| 577 | else |
| 578 | sb.append("invalid"); |
| 579 | sb.append('\n'); |
| 580 | } |
| 581 | for (int i = 0; i < 4; i++) { |
| 582 | if (header.getOpcode() != Opcode.UPDATE) |
| 583 | sb.append(";; " + Section.longString(i) + ":\n"); |
| 584 | else |
| 585 | sb.append(";; " + Section.updString(i) + ":\n"); |
| 586 | sb.append(sectionToString(i) + "\n"); |
| 587 | } |
| 588 | sb.append(";; Message size: " + numBytes() + " bytes"); |
| 589 | return sb.toString(); |
| 590 | } |
| 591 | |
| 592 | /** |
| 593 | * Creates a copy of this Message. This is done by the Resolver before adding |
| 594 | * TSIG and OPT records, for example. |
| 595 | * @see Resolver |
| 596 | * @see TSIGRecord |
| 597 | * @see OPTRecord |
| 598 | */ |
| 599 | public Object |
| 600 | clone() { |
| 601 | Message m = new Message(); |
| 602 | for (int i = 0; i < sections.length; i++) { |
| 603 | if (sections[i] != null) |
| 604 | m.sections[i] = new LinkedList(sections[i]); |
| 605 | } |
| 606 | m.header = (Header) header.clone(); |
| 607 | m.size = size; |
| 608 | return m; |
| 609 | } |
| 610 | |
| 611 | } |