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.util.*; |
| 7 | |
| 8 | /** |
| 9 | * A cache of DNS records. The cache obeys TTLs, so items are purged after |
| 10 | * their validity period is complete. Negative answers are cached, to |
| 11 | * avoid repeated failed DNS queries. The credibility of each RRset is |
| 12 | * maintained, so that more credible records replace less credible records, |
| 13 | * and lookups can specify the minimum credibility of data they are requesting. |
| 14 | * @see RRset |
| 15 | * @see Credibility |
| 16 | * |
| 17 | * @author Brian Wellington |
| 18 | */ |
| 19 | |
| 20 | public class Cache { |
| 21 | |
| 22 | private interface Element { |
| 23 | public boolean expired(); |
| 24 | public int compareCredibility(int cred); |
| 25 | public int getType(); |
| 26 | } |
| 27 | |
| 28 | private static int |
| 29 | limitExpire(long ttl, long maxttl) { |
| 30 | if (maxttl >= 0 && maxttl < ttl) |
| 31 | ttl = maxttl; |
| 32 | long expire = (System.currentTimeMillis() / 1000) + ttl; |
| 33 | if (expire < 0 || expire > Integer.MAX_VALUE) |
| 34 | return Integer.MAX_VALUE; |
| 35 | return (int)expire; |
| 36 | } |
| 37 | |
| 38 | private static class CacheRRset extends RRset implements Element { |
| 39 | private static final long serialVersionUID = 5971755205903597024L; |
| 40 | |
| 41 | int credibility; |
| 42 | int expire; |
| 43 | |
| 44 | public |
| 45 | CacheRRset(Record rec, int cred, long maxttl) { |
| 46 | super(); |
| 47 | this.credibility = cred; |
| 48 | this.expire = limitExpire(rec.getTTL(), maxttl); |
| 49 | addRR(rec); |
| 50 | } |
| 51 | |
| 52 | public |
| 53 | CacheRRset(RRset rrset, int cred, long maxttl) { |
| 54 | super(rrset); |
| 55 | this.credibility = cred; |
| 56 | this.expire = limitExpire(rrset.getTTL(), maxttl); |
| 57 | } |
| 58 | |
| 59 | public final boolean |
| 60 | expired() { |
| 61 | int now = (int)(System.currentTimeMillis() / 1000); |
| 62 | return (now >= expire); |
| 63 | } |
| 64 | |
| 65 | public final int |
| 66 | compareCredibility(int cred) { |
| 67 | return credibility - cred; |
| 68 | } |
| 69 | |
| 70 | public String |
| 71 | toString() { |
| 72 | StringBuffer sb = new StringBuffer(); |
| 73 | sb.append(super.toString()); |
| 74 | sb.append(" cl = "); |
| 75 | sb.append(credibility); |
| 76 | return sb.toString(); |
| 77 | } |
| 78 | } |
| 79 | |
| 80 | private static class NegativeElement implements Element { |
| 81 | int type; |
| 82 | Name name; |
| 83 | int credibility; |
| 84 | int expire; |
| 85 | |
| 86 | public |
| 87 | NegativeElement(Name name, int type, SOARecord soa, int cred, |
| 88 | long maxttl) |
| 89 | { |
| 90 | this.name = name; |
| 91 | this.type = type; |
| 92 | long cttl = 0; |
| 93 | if (soa != null) |
| 94 | cttl = soa.getMinimum(); |
| 95 | this.credibility = cred; |
| 96 | this.expire = limitExpire(cttl, maxttl); |
| 97 | } |
| 98 | |
| 99 | public int |
| 100 | getType() { |
| 101 | return type; |
| 102 | } |
| 103 | |
| 104 | public final boolean |
| 105 | expired() { |
| 106 | int now = (int)(System.currentTimeMillis() / 1000); |
| 107 | return (now >= expire); |
| 108 | } |
| 109 | |
| 110 | public final int |
| 111 | compareCredibility(int cred) { |
| 112 | return credibility - cred; |
| 113 | } |
| 114 | |
| 115 | public String |
| 116 | toString() { |
| 117 | StringBuffer sb = new StringBuffer(); |
| 118 | if (type == 0) |
| 119 | sb.append("NXDOMAIN " + name); |
| 120 | else |
| 121 | sb.append("NXRRSET " + name + " " + Type.string(type)); |
| 122 | sb.append(" cl = "); |
| 123 | sb.append(credibility); |
| 124 | return sb.toString(); |
| 125 | } |
| 126 | } |
| 127 | |
| 128 | private static class CacheMap extends LinkedHashMap { |
| 129 | private int maxsize = -1; |
| 130 | |
| 131 | CacheMap(int maxsize) { |
| 132 | super(16, (float) 0.75, true); |
| 133 | this.maxsize = maxsize; |
| 134 | } |
| 135 | |
| 136 | int |
| 137 | getMaxSize() { |
| 138 | return maxsize; |
| 139 | } |
| 140 | |
| 141 | void |
| 142 | setMaxSize(int maxsize) { |
| 143 | /* |
| 144 | * Note that this doesn't shrink the size of the map if |
| 145 | * the maximum size is lowered, but it should shrink as |
| 146 | * entries expire. |
| 147 | */ |
| 148 | this.maxsize = maxsize; |
| 149 | } |
| 150 | |
| 151 | protected boolean removeEldestEntry(Map.Entry eldest) { |
| 152 | return maxsize >= 0 && size() > maxsize; |
| 153 | } |
| 154 | } |
| 155 | |
| 156 | private CacheMap data; |
| 157 | private int maxncache = -1; |
| 158 | private int maxcache = -1; |
| 159 | private int dclass; |
| 160 | |
| 161 | private static final int defaultMaxEntries = 50000; |
| 162 | |
| 163 | /** |
| 164 | * Creates an empty Cache |
| 165 | * |
| 166 | * @param dclass The DNS class of this cache |
| 167 | * @see DClass |
| 168 | */ |
| 169 | public |
| 170 | Cache(int dclass) { |
| 171 | this.dclass = dclass; |
| 172 | data = new CacheMap(defaultMaxEntries); |
| 173 | } |
| 174 | |
| 175 | /** |
| 176 | * Creates an empty Cache for class IN. |
| 177 | * @see DClass |
| 178 | */ |
| 179 | public |
| 180 | Cache() { |
| 181 | this(DClass.IN); |
| 182 | } |
| 183 | |
| 184 | /** |
| 185 | * Creates a Cache which initially contains all records in the specified file. |
| 186 | */ |
| 187 | public |
| 188 | Cache(String file) throws IOException { |
| 189 | data = new CacheMap(defaultMaxEntries); |
| 190 | Master m = new Master(file); |
| 191 | Record record; |
| 192 | while ((record = m.nextRecord()) != null) |
| 193 | addRecord(record, Credibility.HINT, m); |
| 194 | } |
| 195 | |
| 196 | private synchronized Object |
| 197 | exactName(Name name) { |
| 198 | return data.get(name); |
| 199 | } |
| 200 | |
| 201 | private synchronized void |
| 202 | removeName(Name name) { |
| 203 | data.remove(name); |
| 204 | } |
| 205 | |
| 206 | private synchronized Element [] |
| 207 | allElements(Object types) { |
| 208 | if (types instanceof List) { |
| 209 | List typelist = (List) types; |
| 210 | int size = typelist.size(); |
| 211 | return (Element []) typelist.toArray(new Element[size]); |
| 212 | } else { |
| 213 | Element set = (Element) types; |
| 214 | return new Element[] {set}; |
| 215 | } |
| 216 | } |
| 217 | |
| 218 | private synchronized Element |
| 219 | oneElement(Name name, Object types, int type, int minCred) { |
| 220 | Element found = null; |
| 221 | |
| 222 | if (type == Type.ANY) |
| 223 | throw new IllegalArgumentException("oneElement(ANY)"); |
| 224 | if (types instanceof List) { |
| 225 | List list = (List) types; |
| 226 | for (int i = 0; i < list.size(); i++) { |
| 227 | Element set = (Element) list.get(i); |
| 228 | if (set.getType() == type) { |
| 229 | found = set; |
| 230 | break; |
| 231 | } |
| 232 | } |
| 233 | } else { |
| 234 | Element set = (Element) types; |
| 235 | if (set.getType() == type) |
| 236 | found = set; |
| 237 | } |
| 238 | if (found == null) |
| 239 | return null; |
| 240 | if (found.expired()) { |
| 241 | removeElement(name, type); |
| 242 | return null; |
| 243 | } |
| 244 | if (found.compareCredibility(minCred) < 0) |
| 245 | return null; |
| 246 | return found; |
| 247 | } |
| 248 | |
| 249 | private synchronized Element |
| 250 | findElement(Name name, int type, int minCred) { |
| 251 | Object types = exactName(name); |
| 252 | if (types == null) |
| 253 | return null; |
| 254 | return oneElement(name, types, type, minCred); |
| 255 | } |
| 256 | |
| 257 | private synchronized void |
| 258 | addElement(Name name, Element element) { |
| 259 | Object types = data.get(name); |
| 260 | if (types == null) { |
| 261 | data.put(name, element); |
| 262 | return; |
| 263 | } |
| 264 | int type = element.getType(); |
| 265 | if (types instanceof List) { |
| 266 | List list = (List) types; |
| 267 | for (int i = 0; i < list.size(); i++) { |
| 268 | Element elt = (Element) list.get(i); |
| 269 | if (elt.getType() == type) { |
| 270 | list.set(i, element); |
| 271 | return; |
| 272 | } |
| 273 | } |
| 274 | list.add(element); |
| 275 | } else { |
| 276 | Element elt = (Element) types; |
| 277 | if (elt.getType() == type) |
| 278 | data.put(name, element); |
| 279 | else { |
| 280 | LinkedList list = new LinkedList(); |
| 281 | list.add(elt); |
| 282 | list.add(element); |
| 283 | data.put(name, list); |
| 284 | } |
| 285 | } |
| 286 | } |
| 287 | |
| 288 | private synchronized void |
| 289 | removeElement(Name name, int type) { |
| 290 | Object types = data.get(name); |
| 291 | if (types == null) { |
| 292 | return; |
| 293 | } |
| 294 | if (types instanceof List) { |
| 295 | List list = (List) types; |
| 296 | for (int i = 0; i < list.size(); i++) { |
| 297 | Element elt = (Element) list.get(i); |
| 298 | if (elt.getType() == type) { |
| 299 | list.remove(i); |
| 300 | if (list.size() == 0) |
| 301 | data.remove(name); |
| 302 | return; |
| 303 | } |
| 304 | } |
| 305 | } else { |
| 306 | Element elt = (Element) types; |
| 307 | if (elt.getType() != type) |
| 308 | return; |
| 309 | data.remove(name); |
| 310 | } |
| 311 | } |
| 312 | |
| 313 | /** Empties the Cache. */ |
| 314 | public synchronized void |
| 315 | clearCache() { |
| 316 | data.clear(); |
| 317 | } |
| 318 | |
| 319 | /** |
| 320 | * Adds a record to the Cache. |
| 321 | * @param r The record to be added |
| 322 | * @param cred The credibility of the record |
| 323 | * @param o The source of the record (this could be a Message, for example) |
| 324 | * @see Record |
| 325 | */ |
| 326 | public synchronized void |
| 327 | addRecord(Record r, int cred, Object o) { |
| 328 | Name name = r.getName(); |
| 329 | int type = r.getRRsetType(); |
| 330 | if (!Type.isRR(type)) |
| 331 | return; |
| 332 | Element element = findElement(name, type, cred); |
| 333 | if (element == null) { |
| 334 | CacheRRset crrset = new CacheRRset(r, cred, maxcache); |
| 335 | addRRset(crrset, cred); |
| 336 | } else if (element.compareCredibility(cred) == 0) { |
| 337 | if (element instanceof CacheRRset) { |
| 338 | CacheRRset crrset = (CacheRRset) element; |
| 339 | crrset.addRR(r); |
| 340 | } |
| 341 | } |
| 342 | } |
| 343 | |
| 344 | /** |
| 345 | * Adds an RRset to the Cache. |
| 346 | * @param rrset The RRset to be added |
| 347 | * @param cred The credibility of these records |
| 348 | * @see RRset |
| 349 | */ |
| 350 | public synchronized void |
| 351 | addRRset(RRset rrset, int cred) { |
| 352 | long ttl = rrset.getTTL(); |
| 353 | Name name = rrset.getName(); |
| 354 | int type = rrset.getType(); |
| 355 | Element element = findElement(name, type, 0); |
| 356 | if (ttl == 0) { |
| 357 | if (element != null && element.compareCredibility(cred) <= 0) |
| 358 | removeElement(name, type); |
| 359 | } else { |
| 360 | if (element != null && element.compareCredibility(cred) <= 0) |
| 361 | element = null; |
| 362 | if (element == null) { |
| 363 | CacheRRset crrset; |
| 364 | if (rrset instanceof CacheRRset) |
| 365 | crrset = (CacheRRset) rrset; |
| 366 | else |
| 367 | crrset = new CacheRRset(rrset, cred, maxcache); |
| 368 | addElement(name, crrset); |
| 369 | } |
| 370 | } |
| 371 | } |
| 372 | |
| 373 | /** |
| 374 | * Adds a negative entry to the Cache. |
| 375 | * @param name The name of the negative entry |
| 376 | * @param type The type of the negative entry |
| 377 | * @param soa The SOA record to add to the negative cache entry, or null. |
| 378 | * The negative cache ttl is derived from the SOA. |
| 379 | * @param cred The credibility of the negative entry |
| 380 | */ |
| 381 | public synchronized void |
| 382 | addNegative(Name name, int type, SOARecord soa, int cred) { |
| 383 | long ttl = 0; |
| 384 | if (soa != null) |
| 385 | ttl = soa.getTTL(); |
| 386 | Element element = findElement(name, type, 0); |
| 387 | if (ttl == 0) { |
| 388 | if (element != null && element.compareCredibility(cred) <= 0) |
| 389 | removeElement(name, type); |
| 390 | } else { |
| 391 | if (element != null && element.compareCredibility(cred) <= 0) |
| 392 | element = null; |
| 393 | if (element == null) |
| 394 | addElement(name, new NegativeElement(name, type, |
| 395 | soa, cred, |
| 396 | maxncache)); |
| 397 | } |
| 398 | } |
| 399 | |
| 400 | /** |
| 401 | * Finds all matching sets or something that causes the lookup to stop. |
| 402 | */ |
| 403 | protected synchronized SetResponse |
| 404 | lookup(Name name, int type, int minCred) { |
| 405 | int labels; |
| 406 | int tlabels; |
| 407 | Element element; |
| 408 | Name tname; |
| 409 | Object types; |
| 410 | SetResponse sr; |
| 411 | |
| 412 | labels = name.labels(); |
| 413 | |
| 414 | for (tlabels = labels; tlabels >= 1; tlabels--) { |
| 415 | boolean isRoot = (tlabels == 1); |
| 416 | boolean isExact = (tlabels == labels); |
| 417 | |
| 418 | if (isRoot) |
| 419 | tname = Name.root; |
| 420 | else if (isExact) |
| 421 | tname = name; |
| 422 | else |
| 423 | tname = new Name(name, labels - tlabels); |
| 424 | |
| 425 | types = data.get(tname); |
| 426 | if (types == null) |
| 427 | continue; |
| 428 | |
| 429 | /* |
| 430 | * If this is the name, look for the actual type or a CNAME |
| 431 | * (unless it's an ANY query, where we return everything). |
| 432 | * Otherwise, look for a DNAME. |
| 433 | */ |
| 434 | if (isExact && type == Type.ANY) { |
| 435 | sr = new SetResponse(SetResponse.SUCCESSFUL); |
| 436 | Element [] elements = allElements(types); |
| 437 | int added = 0; |
| 438 | for (int i = 0; i < elements.length; i++) { |
| 439 | element = elements[i]; |
| 440 | if (element.expired()) { |
| 441 | removeElement(tname, element.getType()); |
| 442 | continue; |
| 443 | } |
| 444 | if (!(element instanceof CacheRRset)) |
| 445 | continue; |
| 446 | if (element.compareCredibility(minCred) < 0) |
| 447 | continue; |
| 448 | sr.addRRset((CacheRRset)element); |
| 449 | added++; |
| 450 | } |
| 451 | /* There were positive entries */ |
| 452 | if (added > 0) |
| 453 | return sr; |
| 454 | } else if (isExact) { |
| 455 | element = oneElement(tname, types, type, minCred); |
| 456 | if (element != null && |
| 457 | element instanceof CacheRRset) |
| 458 | { |
| 459 | sr = new SetResponse(SetResponse.SUCCESSFUL); |
| 460 | sr.addRRset((CacheRRset) element); |
| 461 | return sr; |
| 462 | } else if (element != null) { |
| 463 | sr = new SetResponse(SetResponse.NXRRSET); |
| 464 | return sr; |
| 465 | } |
| 466 | |
| 467 | element = oneElement(tname, types, Type.CNAME, minCred); |
| 468 | if (element != null && |
| 469 | element instanceof CacheRRset) |
| 470 | { |
| 471 | return new SetResponse(SetResponse.CNAME, |
| 472 | (CacheRRset) element); |
| 473 | } |
| 474 | } else { |
| 475 | element = oneElement(tname, types, Type.DNAME, minCred); |
| 476 | if (element != null && |
| 477 | element instanceof CacheRRset) |
| 478 | { |
| 479 | return new SetResponse(SetResponse.DNAME, |
| 480 | (CacheRRset) element); |
| 481 | } |
| 482 | } |
| 483 | |
| 484 | /* Look for an NS */ |
| 485 | element = oneElement(tname, types, Type.NS, minCred); |
| 486 | if (element != null && element instanceof CacheRRset) |
| 487 | return new SetResponse(SetResponse.DELEGATION, |
| 488 | (CacheRRset) element); |
| 489 | |
| 490 | /* Check for the special NXDOMAIN element. */ |
| 491 | if (isExact) { |
| 492 | element = oneElement(tname, types, 0, minCred); |
| 493 | if (element != null) |
| 494 | return SetResponse.ofType(SetResponse.NXDOMAIN); |
| 495 | } |
| 496 | |
| 497 | } |
| 498 | return SetResponse.ofType(SetResponse.UNKNOWN); |
| 499 | } |
| 500 | |
| 501 | /** |
| 502 | * Looks up Records in the Cache. This follows CNAMEs and handles negatively |
| 503 | * cached data. |
| 504 | * @param name The name to look up |
| 505 | * @param type The type to look up |
| 506 | * @param minCred The minimum acceptable credibility |
| 507 | * @return A SetResponse object |
| 508 | * @see SetResponse |
| 509 | * @see Credibility |
| 510 | */ |
| 511 | public SetResponse |
| 512 | lookupRecords(Name name, int type, int minCred) { |
| 513 | return lookup(name, type, minCred); |
| 514 | } |
| 515 | |
| 516 | private RRset [] |
| 517 | findRecords(Name name, int type, int minCred) { |
| 518 | SetResponse cr = lookupRecords(name, type, minCred); |
| 519 | if (cr.isSuccessful()) |
| 520 | return cr.answers(); |
| 521 | else |
| 522 | return null; |
| 523 | } |
| 524 | |
| 525 | /** |
| 526 | * Looks up credible Records in the Cache (a wrapper around lookupRecords). |
| 527 | * Unlike lookupRecords, this given no indication of why failure occurred. |
| 528 | * @param name The name to look up |
| 529 | * @param type The type to look up |
| 530 | * @return An array of RRsets, or null |
| 531 | * @see Credibility |
| 532 | */ |
| 533 | public RRset [] |
| 534 | findRecords(Name name, int type) { |
| 535 | return findRecords(name, type, Credibility.NORMAL); |
| 536 | } |
| 537 | |
| 538 | /** |
| 539 | * Looks up Records in the Cache (a wrapper around lookupRecords). Unlike |
| 540 | * lookupRecords, this given no indication of why failure occurred. |
| 541 | * @param name The name to look up |
| 542 | * @param type The type to look up |
| 543 | * @return An array of RRsets, or null |
| 544 | * @see Credibility |
| 545 | */ |
| 546 | public RRset [] |
| 547 | findAnyRecords(Name name, int type) { |
| 548 | return findRecords(name, type, Credibility.GLUE); |
| 549 | } |
| 550 | |
| 551 | private final int |
| 552 | getCred(int section, boolean isAuth) { |
| 553 | if (section == Section.ANSWER) { |
| 554 | if (isAuth) |
| 555 | return Credibility.AUTH_ANSWER; |
| 556 | else |
| 557 | return Credibility.NONAUTH_ANSWER; |
| 558 | } else if (section == Section.AUTHORITY) { |
| 559 | if (isAuth) |
| 560 | return Credibility.AUTH_AUTHORITY; |
| 561 | else |
| 562 | return Credibility.NONAUTH_AUTHORITY; |
| 563 | } else if (section == Section.ADDITIONAL) { |
| 564 | return Credibility.ADDITIONAL; |
| 565 | } else |
| 566 | throw new IllegalArgumentException("getCred: invalid section"); |
| 567 | } |
| 568 | |
| 569 | private static void |
| 570 | markAdditional(RRset rrset, Set names) { |
| 571 | Record first = rrset.first(); |
| 572 | if (first.getAdditionalName() == null) |
| 573 | return; |
| 574 | |
| 575 | Iterator it = rrset.rrs(); |
| 576 | while (it.hasNext()) { |
| 577 | Record r = (Record) it.next(); |
| 578 | Name name = r.getAdditionalName(); |
| 579 | if (name != null) |
| 580 | names.add(name); |
| 581 | } |
| 582 | } |
| 583 | |
| 584 | /** |
| 585 | * Adds all data from a Message into the Cache. Each record is added with |
| 586 | * the appropriate credibility, and negative answers are cached as such. |
| 587 | * @param in The Message to be added |
| 588 | * @return A SetResponse that reflects what would be returned from a cache |
| 589 | * lookup, or null if nothing useful could be cached from the message. |
| 590 | * @see Message |
| 591 | */ |
| 592 | public SetResponse |
| 593 | addMessage(Message in) { |
| 594 | boolean isAuth = in.getHeader().getFlag(Flags.AA); |
| 595 | Record question = in.getQuestion(); |
| 596 | Name qname; |
| 597 | Name curname; |
| 598 | int qtype; |
| 599 | int qclass; |
| 600 | int cred; |
| 601 | int rcode = in.getHeader().getRcode(); |
| 602 | boolean completed = false; |
| 603 | RRset [] answers, auth, addl; |
| 604 | SetResponse response = null; |
| 605 | boolean verbose = Options.check("verbosecache"); |
| 606 | HashSet additionalNames; |
| 607 | |
| 608 | if ((rcode != Rcode.NOERROR && rcode != Rcode.NXDOMAIN) || |
| 609 | question == null) |
| 610 | return null; |
| 611 | |
| 612 | qname = question.getName(); |
| 613 | qtype = question.getType(); |
| 614 | qclass = question.getDClass(); |
| 615 | |
| 616 | curname = qname; |
| 617 | |
| 618 | additionalNames = new HashSet(); |
| 619 | |
| 620 | answers = in.getSectionRRsets(Section.ANSWER); |
| 621 | for (int i = 0; i < answers.length; i++) { |
| 622 | if (answers[i].getDClass() != qclass) |
| 623 | continue; |
| 624 | int type = answers[i].getType(); |
| 625 | Name name = answers[i].getName(); |
| 626 | cred = getCred(Section.ANSWER, isAuth); |
| 627 | if ((type == qtype || qtype == Type.ANY) && |
| 628 | name.equals(curname)) |
| 629 | { |
| 630 | addRRset(answers[i], cred); |
| 631 | completed = true; |
| 632 | if (curname == qname) { |
| 633 | if (response == null) |
| 634 | response = new SetResponse( |
| 635 | SetResponse.SUCCESSFUL); |
| 636 | response.addRRset(answers[i]); |
| 637 | } |
| 638 | markAdditional(answers[i], additionalNames); |
| 639 | } else if (type == Type.CNAME && name.equals(curname)) { |
| 640 | CNAMERecord cname; |
| 641 | addRRset(answers[i], cred); |
| 642 | if (curname == qname) |
| 643 | response = new SetResponse(SetResponse.CNAME, |
| 644 | answers[i]); |
| 645 | cname = (CNAMERecord) answers[i].first(); |
| 646 | curname = cname.getTarget(); |
| 647 | } else if (type == Type.DNAME && curname.subdomain(name)) { |
| 648 | DNAMERecord dname; |
| 649 | addRRset(answers[i], cred); |
| 650 | if (curname == qname) |
| 651 | response = new SetResponse(SetResponse.DNAME, |
| 652 | answers[i]); |
| 653 | dname = (DNAMERecord) answers[i].first(); |
| 654 | try { |
| 655 | curname = curname.fromDNAME(dname); |
| 656 | } |
| 657 | catch (NameTooLongException e) { |
| 658 | break; |
| 659 | } |
| 660 | } |
| 661 | } |
| 662 | |
| 663 | auth = in.getSectionRRsets(Section.AUTHORITY); |
| 664 | RRset soa = null, ns = null; |
| 665 | for (int i = 0; i < auth.length; i++) { |
| 666 | if (auth[i].getType() == Type.SOA && |
| 667 | curname.subdomain(auth[i].getName())) |
| 668 | soa = auth[i]; |
| 669 | else if (auth[i].getType() == Type.NS && |
| 670 | curname.subdomain(auth[i].getName())) |
| 671 | ns = auth[i]; |
| 672 | } |
| 673 | if (!completed) { |
| 674 | /* This is a negative response or a referral. */ |
| 675 | int cachetype = (rcode == Rcode.NXDOMAIN) ? 0 : qtype; |
| 676 | if (rcode == Rcode.NXDOMAIN || soa != null || ns == null) { |
| 677 | /* Negative response */ |
| 678 | cred = getCred(Section.AUTHORITY, isAuth); |
| 679 | SOARecord soarec = null; |
| 680 | if (soa != null) |
| 681 | soarec = (SOARecord) soa.first(); |
| 682 | addNegative(curname, cachetype, soarec, cred); |
| 683 | if (response == null) { |
| 684 | int responseType; |
| 685 | if (rcode == Rcode.NXDOMAIN) |
| 686 | responseType = SetResponse.NXDOMAIN; |
| 687 | else |
| 688 | responseType = SetResponse.NXRRSET; |
| 689 | response = SetResponse.ofType(responseType); |
| 690 | } |
| 691 | /* DNSSEC records are not cached. */ |
| 692 | } else { |
| 693 | /* Referral response */ |
| 694 | cred = getCred(Section.AUTHORITY, isAuth); |
| 695 | addRRset(ns, cred); |
| 696 | markAdditional(ns, additionalNames); |
| 697 | if (response == null) |
| 698 | response = new SetResponse( |
| 699 | SetResponse.DELEGATION, |
| 700 | ns); |
| 701 | } |
| 702 | } else if (rcode == Rcode.NOERROR && ns != null) { |
| 703 | /* Cache the NS set from a positive response. */ |
| 704 | cred = getCred(Section.AUTHORITY, isAuth); |
| 705 | addRRset(ns, cred); |
| 706 | markAdditional(ns, additionalNames); |
| 707 | } |
| 708 | |
| 709 | addl = in.getSectionRRsets(Section.ADDITIONAL); |
| 710 | for (int i = 0; i < addl.length; i++) { |
| 711 | int type = addl[i].getType(); |
| 712 | if (type != Type.A && type != Type.AAAA && type != Type.A6) |
| 713 | continue; |
| 714 | Name name = addl[i].getName(); |
| 715 | if (!additionalNames.contains(name)) |
| 716 | continue; |
| 717 | cred = getCred(Section.ADDITIONAL, isAuth); |
| 718 | addRRset(addl[i], cred); |
| 719 | } |
| 720 | if (verbose) |
| 721 | System.out.println("addMessage: " + response); |
| 722 | return (response); |
| 723 | } |
| 724 | |
| 725 | /** |
| 726 | * Flushes an RRset from the cache |
| 727 | * @param name The name of the records to be flushed |
| 728 | * @param type The type of the records to be flushed |
| 729 | * @see RRset |
| 730 | */ |
| 731 | public void |
| 732 | flushSet(Name name, int type) { |
| 733 | removeElement(name, type); |
| 734 | } |
| 735 | |
| 736 | /** |
| 737 | * Flushes all RRsets with a given name from the cache |
| 738 | * @param name The name of the records to be flushed |
| 739 | * @see RRset |
| 740 | */ |
| 741 | public void |
| 742 | flushName(Name name) { |
| 743 | removeName(name); |
| 744 | } |
| 745 | |
| 746 | /** |
| 747 | * Sets the maximum length of time that a negative response will be stored |
| 748 | * in this Cache. A negative value disables this feature (that is, sets |
| 749 | * no limit). |
| 750 | */ |
| 751 | public void |
| 752 | setMaxNCache(int seconds) { |
| 753 | maxncache = seconds; |
| 754 | } |
| 755 | |
| 756 | /** |
| 757 | * Gets the maximum length of time that a negative response will be stored |
| 758 | * in this Cache. A negative value indicates no limit. |
| 759 | */ |
| 760 | public int |
| 761 | getMaxNCache() { |
| 762 | return maxncache; |
| 763 | } |
| 764 | |
| 765 | /** |
| 766 | * Sets the maximum length of time that records will be stored in this |
| 767 | * Cache. A negative value disables this feature (that is, sets no limit). |
| 768 | */ |
| 769 | public void |
| 770 | setMaxCache(int seconds) { |
| 771 | maxcache = seconds; |
| 772 | } |
| 773 | |
| 774 | /** |
| 775 | * Gets the maximum length of time that records will be stored |
| 776 | * in this Cache. A negative value indicates no limit. |
| 777 | */ |
| 778 | public int |
| 779 | getMaxCache() { |
| 780 | return maxcache; |
| 781 | } |
| 782 | |
| 783 | /** |
| 784 | * Gets the current number of entries in the Cache, where an entry consists |
| 785 | * of all records with a specific Name. |
| 786 | */ |
| 787 | public int |
| 788 | getSize() { |
| 789 | return data.size(); |
| 790 | } |
| 791 | |
| 792 | /** |
| 793 | * Gets the maximum number of entries in the Cache, where an entry consists |
| 794 | * of all records with a specific Name. A negative value is treated as an |
| 795 | * infinite limit. |
| 796 | */ |
| 797 | public int |
| 798 | getMaxEntries() { |
| 799 | return data.getMaxSize(); |
| 800 | } |
| 801 | |
| 802 | /** |
| 803 | * Sets the maximum number of entries in the Cache, where an entry consists |
| 804 | * of all records with a specific Name. A negative value is treated as an |
| 805 | * infinite limit. |
| 806 | * |
| 807 | * Note that setting this to a value lower than the current number |
| 808 | * of entries will not cause the Cache to shrink immediately. |
| 809 | * |
| 810 | * The default maximum number of entries is 50000. |
| 811 | * |
| 812 | * @param entries The maximum number of entries in the Cache. |
| 813 | */ |
| 814 | public void |
| 815 | setMaxEntries(int entries) { |
| 816 | data.setMaxSize(entries); |
| 817 | } |
| 818 | |
| 819 | /** |
| 820 | * Returns the DNS class of this cache. |
| 821 | */ |
| 822 | public int |
| 823 | getDClass() { |
| 824 | return dclass; |
| 825 | } |
| 826 | |
| 827 | /** |
| 828 | * Returns the contents of the Cache as a string. |
| 829 | */ |
| 830 | public String |
| 831 | toString() { |
| 832 | StringBuffer sb = new StringBuffer(); |
| 833 | synchronized (this) { |
| 834 | Iterator it = data.values().iterator(); |
| 835 | while (it.hasNext()) { |
| 836 | Element [] elements = allElements(it.next()); |
| 837 | for (int i = 0; i < elements.length; i++) { |
| 838 | sb.append(elements[i]); |
| 839 | sb.append("\n"); |
| 840 | } |
| 841 | } |
| 842 | } |
| 843 | return sb.toString(); |
| 844 | } |
| 845 | |
| 846 | } |