git.meshlink.io Git - catta/blob - avahi-core/dns.c

   1 /* $Id$ */
   2
   3 /***
   4   This file is part of avahi.
   5
   6   avahi is free software; you can redistribute it and/or modify it
   7   under the terms of the GNU Lesser General Public License as
   8   published by the Free Software Foundation; either version 2.1 of the
   9   License, or (at your option) any later version.
  10
  11   avahi is distributed in the hope that it will be useful, but WITHOUT
  12   ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  13   or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General
  14   Public License for more details.
  15
  16   You should have received a copy of the GNU Lesser General Public
  17   License along with avahi; if not, write to the Free Software
  18   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
  19   USA.
  20 ***/
  21
  22 #ifdef HAVE_CONFIG_H
  23 #include <config.h>
  24 #endif
  25
  26 #include <stdlib.h>
  27 #include <string.h>
  28 #include <stdio.h>
  29 #include <assert.h>
  30
  31 #include <netinet/in.h>
  32
  33 #include <avahi-common/defs.h>
  34 #include <avahi-common/domain.h>
  35 #include <avahi-common/malloc.h>
  36
  37 #include "dns.h"
  38 #include "log.h"
  39
  40 AvahiDnsPacket* avahi_dns_packet_new(unsigned mtu) {
  41     AvahiDnsPacket *p;
  42     size_t max_size;
  43
  44     if (mtu <= 0)
  45         max_size = AVAHI_DNS_PACKET_SIZE_MAX;
  46     else if (mtu >= AVAHI_DNS_PACKET_EXTRA_SIZE)
  47         max_size = mtu - AVAHI_DNS_PACKET_EXTRA_SIZE;
  48     else
  49         max_size = 0;
  50
  51     if (max_size < AVAHI_DNS_PACKET_HEADER_SIZE)
  52         max_size = AVAHI_DNS_PACKET_HEADER_SIZE;
  53
  54     if (!(p = avahi_malloc(sizeof(AvahiDnsPacket) + max_size)))
  55         return p;
  56
  57     p->size = p->rindex = AVAHI_DNS_PACKET_HEADER_SIZE;
  58     p->max_size = max_size;
  59     p->name_table = NULL;
  60     p->data = NULL;
  61
  62     memset(AVAHI_DNS_PACKET_DATA(p), 0, p->size);
  63     return p;
  64 }
  65
  66 AvahiDnsPacket* avahi_dns_packet_new_query(unsigned mtu) {
  67     AvahiDnsPacket *p;
  68
  69     if (!(p = avahi_dns_packet_new(mtu)))
  70         return NULL;
  71
  72     avahi_dns_packet_set_field(p, AVAHI_DNS_FIELD_FLAGS, AVAHI_DNS_FLAGS(0, 0, 0, 0, 0, 0, 0, 0, 0, 0));
  73     return p;
  74 }
  75
  76 AvahiDnsPacket* avahi_dns_packet_new_response(unsigned mtu, int aa) {
  77     AvahiDnsPacket *p;
  78
  79     if (!(p = avahi_dns_packet_new(mtu)))
  80         return NULL;
  81
  82     avahi_dns_packet_set_field(p, AVAHI_DNS_FIELD_FLAGS, AVAHI_DNS_FLAGS(1, 0, aa, 0, 0, 0, 0, 0, 0, 0));
  83     return p;
  84 }
  85
  86 AvahiDnsPacket* avahi_dns_packet_new_reply(AvahiDnsPacket* p, unsigned mtu, int copy_queries, int aa) {
  87     AvahiDnsPacket *r;
  88     assert(p);
  89
  90     if (!(r = avahi_dns_packet_new_response(mtu, aa)))
  91         return NULL;
  92
  93     if (copy_queries) {
  94         unsigned saved_rindex;
  95         uint32_t n;
  96
  97         saved_rindex = p->rindex;
  98         p->rindex = AVAHI_DNS_PACKET_HEADER_SIZE;
  99
 100         for (n = avahi_dns_packet_get_field(p, AVAHI_DNS_FIELD_QDCOUNT); n > 0; n--) {
 101             AvahiKey *k;
 102             int unicast_response;
 103
 104             if ((k = avahi_dns_packet_consume_key(p, &unicast_response))) {
 105                 avahi_dns_packet_append_key(r, k, unicast_response);
 106                 avahi_key_unref(k);
 107             }
 108         }
 109
 110         p->rindex = saved_rindex;
 111
 112         avahi_dns_packet_set_field(r, AVAHI_DNS_FIELD_QDCOUNT, avahi_dns_packet_get_field(p, AVAHI_DNS_FIELD_QDCOUNT));
 113     }
 114
 115     avahi_dns_packet_set_field(r, AVAHI_DNS_FIELD_ID, avahi_dns_packet_get_field(p, AVAHI_DNS_FIELD_ID));
 116
 117     avahi_dns_packet_set_field(r, AVAHI_DNS_FIELD_FLAGS,
 118                                (avahi_dns_packet_get_field(r, AVAHI_DNS_FIELD_FLAGS) & ~AVAHI_DNS_FLAG_OPCODE) |
 119                                (avahi_dns_packet_get_field(p, AVAHI_DNS_FIELD_FLAGS) & AVAHI_DNS_FLAG_OPCODE));
 120
 121     return r;
 122 }
 123
 124
 125 void avahi_dns_packet_free(AvahiDnsPacket *p) {
 126     assert(p);
 127
 128     if (p->name_table)
 129         avahi_hashmap_free(p->name_table);
 130
 131     avahi_free(p);
 132 }
 133
 134 void avahi_dns_packet_set_field(AvahiDnsPacket *p, unsigned idx, uint16_t v) {
 135     assert(p);
 136     assert(idx < AVAHI_DNS_PACKET_HEADER_SIZE);
 137
 138     ((uint16_t*) AVAHI_DNS_PACKET_DATA(p))[idx] = htons(v);
 139 }
 140
 141 uint16_t avahi_dns_packet_get_field(AvahiDnsPacket *p, unsigned idx) {
 142     assert(p);
 143     assert(idx < AVAHI_DNS_PACKET_HEADER_SIZE);
 144
 145     return ntohs(((uint16_t*) AVAHI_DNS_PACKET_DATA(p))[idx]);
 146 }
 147
 148 void avahi_dns_packet_inc_field(AvahiDnsPacket *p, unsigned idx) {
 149     assert(p);
 150     assert(idx < AVAHI_DNS_PACKET_HEADER_SIZE);
 151
 152     avahi_dns_packet_set_field(p, idx, avahi_dns_packet_get_field(p, idx) + 1);
 153 }
 154
 155 uint8_t* avahi_dns_packet_append_name(AvahiDnsPacket *p, const char *name) {
 156     uint8_t *d, *saved_ptr = NULL;
 157     size_t saved_size;
 158
 159     assert(p);
 160     assert(name);
 161
 162     saved_size = p->size;
 163     saved_ptr = avahi_dns_packet_extend(p, 0);
 164
 165     while (*name) {
 166         uint8_t* prev;
 167         const char *pname;
 168         char label[64], *u;
 169
 170         /* Check whether we can compress this name. */
 171
 172         if (p->name_table && (prev = avahi_hashmap_lookup(p->name_table, name))) {
 173             unsigned idx;
 174
 175             assert(prev >= AVAHI_DNS_PACKET_DATA(p));
 176             idx = (unsigned) (prev - AVAHI_DNS_PACKET_DATA(p));
 177
 178             assert(idx < p->size);
 179
 180             if (idx < 0x4000) {
 181                 uint8_t *t;
 182                 if (!(t = (uint8_t*) avahi_dns_packet_extend(p, sizeof(uint16_t))))
 183                     return NULL;
 184
 185                 t[0] = (uint8_t) ((0xC000 | idx) >> 8);
 186                 t[1] = (uint8_t) idx;
 187                 return saved_ptr;
 188             }
 189         }
 190
 191         pname = name;
 192
 193         if (!(avahi_unescape_label(&name, label, sizeof(label))))
 194             goto fail;
 195
 196         if (!(d = avahi_dns_packet_append_string(p, label)))
 197             goto fail;
 198
 199         if (!p->name_table)
 200             /* This works only for normalized domain names */
 201             p->name_table = avahi_hashmap_new(avahi_string_hash, avahi_string_equal, avahi_free, NULL);
 202
 203         if (!(u = avahi_strdup(pname)))
 204             avahi_log_error("avahi_strdup() failed.");
 205         else
 206             avahi_hashmap_insert(p->name_table, u, d);
 207     }
 208
 209     if (!(d = avahi_dns_packet_extend(p, 1)))
 210         goto fail;
 211
 212     *d = 0;
 213
 214     return saved_ptr;
 215
 216 fail:
 217     p->size = saved_size;
 218     return NULL;
 219 }
 220
 221 uint8_t* avahi_dns_packet_append_uint16(AvahiDnsPacket *p, uint16_t v) {
 222     uint8_t *d;
 223     assert(p);
 224
 225     if (!(d = avahi_dns_packet_extend(p, sizeof(uint16_t))))
 226         return NULL;
 227
 228     d[0] = (uint8_t) (v >> 8);
 229     d[1] = (uint8_t) v;
 230     return d;
 231 }
 232
 233 uint8_t *avahi_dns_packet_append_uint32(AvahiDnsPacket *p, uint32_t v) {
 234     uint8_t *d;
 235     assert(p);
 236
 237     if (!(d = avahi_dns_packet_extend(p, sizeof(uint32_t))))
 238         return NULL;
 239
 240     d[0] = (uint8_t) (v >> 24);
 241     d[1] = (uint8_t) (v >> 16);
 242     d[2] = (uint8_t) (v >> 8);
 243     d[3] = (uint8_t) v;
 244
 245     return d;
 246 }
 247
 248 uint8_t *avahi_dns_packet_append_bytes(AvahiDnsPacket  *p, const void *b, size_t l) {
 249     uint8_t* d;
 250
 251     assert(p);
 252     assert(b);
 253     assert(l);
 254
 255     if (!(d = avahi_dns_packet_extend(p, l)))
 256         return NULL;
 257
 258     memcpy(d, b, l);
 259     return d;
 260 }
 261
 262 uint8_t* avahi_dns_packet_append_string(AvahiDnsPacket *p, const char *s) {
 263     uint8_t* d;
 264     size_t k;
 265
 266     assert(p);
 267     assert(s);
 268
 269     if ((k = strlen(s)) >= 255)
 270         k = 255;
 271
 272     if (!(d = avahi_dns_packet_extend(p, k+1)))
 273         return NULL;
 274
 275     *d = (uint8_t) k;
 276     memcpy(d+1, s, k);
 277
 278     return d;
 279 }
 280
 281 uint8_t *avahi_dns_packet_extend(AvahiDnsPacket *p, size_t l) {
 282     uint8_t *d;
 283
 284     assert(p);
 285
 286     if (p->size+l > p->max_size)
 287         return NULL;
 288
 289     d = AVAHI_DNS_PACKET_DATA(p) + p->size;
 290     p->size += l;
 291
 292     return d;
 293 }
 294
 295 int avahi_dns_packet_check_valid(AvahiDnsPacket *p) {
 296     uint16_t flags;
 297     assert(p);
 298
 299     if (p->size < AVAHI_DNS_PACKET_HEADER_SIZE)
 300         return -1;
 301
 302     flags = avahi_dns_packet_get_field(p, AVAHI_DNS_FIELD_FLAGS);
 303
 304     if (flags & AVAHI_DNS_FLAG_OPCODE)
 305         return -1;
 306
 307     return 0;
 308 }
 309
 310 int avahi_dns_packet_check_valid_multicast(AvahiDnsPacket *p) {
 311     uint16_t flags;
 312     assert(p);
 313
 314     if (avahi_dns_packet_check_valid(p) < 0)
 315         return -1;
 316
 317     flags = avahi_dns_packet_get_field(p, AVAHI_DNS_FIELD_FLAGS);
 318
 319     if (flags & AVAHI_DNS_FLAG_RCODE)
 320         return -1;
 321
 322     return 0;
 323 }
 324
 325 int avahi_dns_packet_is_query(AvahiDnsPacket *p) {
 326     assert(p);
 327
 328     return !(avahi_dns_packet_get_field(p, AVAHI_DNS_FIELD_FLAGS) & AVAHI_DNS_FLAG_QR);
 329 }
 330
 331 static int consume_labels(AvahiDnsPacket *p, unsigned idx, char *ret_name, size_t l) {
 332     int ret = 0;
 333     int compressed = 0;
 334     int first_label = 1;
 335     unsigned label_ptr;
 336     int i;
 337     assert(p && ret_name && l);
 338
 339     for (i = 0; i < AVAHI_DNS_LABELS_MAX; i++) {
 340         uint8_t n;
 341
 342         if (idx+1 > p->size)
 343             return -1;
 344
 345         n = AVAHI_DNS_PACKET_DATA(p)[idx];
 346
 347         if (!n) {
 348             idx++;
 349             if (!compressed)
 350                 ret++;
 351
 352             if (l < 1)
 353                 return -1;
 354             *ret_name = 0;
 355
 356             return ret;
 357
 358         } else if (n <= 63) {
 359             /* Uncompressed label */
 360             idx++;
 361             if (!compressed)
 362                 ret++;
 363
 364             if (idx + n > p->size)
 365                 return -1;
 366
 367             if ((size_t) n + 1 > l)
 368                 return -1;
 369
 370             if (!first_label) {
 371                 *(ret_name++) = '.';
 372                 l--;
 373             } else
 374                 first_label = 0;
 375
 376             if (!(avahi_escape_label((char*) AVAHI_DNS_PACKET_DATA(p) + idx, n, &ret_name, &l)))
 377                 return -1;
 378
 379             idx += n;
 380
 381             if (!compressed)
 382                 ret += n;
 383         } else if ((n & 0xC0) == 0xC0) {
 384             /* Compressed label */
 385
 386             if (idx+2 > p->size)
 387                 return -1;
 388
 389             label_ptr = ((unsigned) (AVAHI_DNS_PACKET_DATA(p)[idx] & ~0xC0)) << 8 | AVAHI_DNS_PACKET_DATA(p)[idx+1];
 390
 391             if ((label_ptr < AVAHI_DNS_PACKET_HEADER_SIZE) || (label_ptr >= idx))
 392                 return -1;
 393
 394             idx = label_ptr;
 395
 396             if (!compressed)
 397                 ret += 2;
 398
 399             compressed = 1;
 400         } else
 401             return -1;
 402     }
 403 }
 404
 405 int avahi_dns_packet_consume_name(AvahiDnsPacket *p, char *ret_name, size_t l) {
 406     int r;
 407
 408     if ((r = consume_labels(p, p->rindex, ret_name, l)) < 0)
 409         return -1;
 410
 411     p->rindex += r;
 412     return 0;
 413 }
 414
 415 int avahi_dns_packet_consume_uint16(AvahiDnsPacket *p, uint16_t *ret_v) {
 416     uint8_t *d;
 417
 418     assert(p);
 419     assert(ret_v);
 420
 421     if (p->rindex + sizeof(uint16_t) > p->size)
 422         return -1;
 423
 424     d = (uint8_t*) (AVAHI_DNS_PACKET_DATA(p) + p->rindex);
 425     *ret_v = (d[0] << 8) | d[1];
 426     p->rindex += sizeof(uint16_t);
 427
 428     return 0;
 429 }
 430
 431 int avahi_dns_packet_consume_uint32(AvahiDnsPacket *p, uint32_t *ret_v) {
 432     uint8_t* d;
 433
 434     assert(p);
 435     assert(ret_v);
 436
 437     if (p->rindex + sizeof(uint32_t) > p->size)
 438         return -1;
 439
 440     d = (uint8_t*) (AVAHI_DNS_PACKET_DATA(p) + p->rindex);
 441     *ret_v = (d[0] << 24) | (d[1] << 16) | (d[2] << 8) | d[3];
 442     p->rindex += sizeof(uint32_t);
 443
 444     return 0;
 445 }
 446
 447 int avahi_dns_packet_consume_bytes(AvahiDnsPacket *p, void * ret_data, size_t l) {
 448     assert(p);
 449     assert(ret_data);
 450     assert(l > 0);
 451
 452     if (p->rindex + l > p->size)
 453         return -1;
 454
 455     memcpy(ret_data, AVAHI_DNS_PACKET_DATA(p) + p->rindex, l);
 456     p->rindex += l;
 457
 458     return 0;
 459 }
 460
 461 int avahi_dns_packet_consume_string(AvahiDnsPacket *p, char *ret_string, size_t l) {
 462     size_t k;
 463
 464     assert(p);
 465     assert(ret_string);
 466     assert(l > 0);
 467
 468     if (p->rindex >= p->size)
 469         return -1;
 470
 471     k = AVAHI_DNS_PACKET_DATA(p)[p->rindex];
 472
 473     if (p->rindex+1+k > p->size)
 474         return -1;
 475
 476     if (l > k+1)
 477         l = k+1;
 478
 479     memcpy(ret_string, AVAHI_DNS_PACKET_DATA(p)+p->rindex+1, l-1);
 480     ret_string[l-1] = 0;
 481
 482     p->rindex += 1+k;
 483
 484     return 0;
 485 }
 486
 487 const void* avahi_dns_packet_get_rptr(AvahiDnsPacket *p) {
 488     assert(p);
 489
 490     if (p->rindex > p->size)
 491         return NULL;
 492
 493     return AVAHI_DNS_PACKET_DATA(p) + p->rindex;
 494 }
 495
 496 int avahi_dns_packet_skip(AvahiDnsPacket *p, size_t length) {
 497     assert(p);
 498
 499     if (p->rindex + length > p->size)
 500         return -1;
 501
 502     p->rindex += length;
 503     return 0;
 504 }
 505
 506 static int parse_rdata(AvahiDnsPacket *p, AvahiRecord *r, uint16_t rdlength) {
 507     char buf[AVAHI_DOMAIN_NAME_MAX];
 508     const void* start;
 509
 510     assert(p);
 511     assert(r);
 512
 513     start = avahi_dns_packet_get_rptr(p);
 514
 515     switch (r->key->type) {
 516         case AVAHI_DNS_TYPE_PTR:
 517         case AVAHI_DNS_TYPE_CNAME:
 518         case AVAHI_DNS_TYPE_NS:
 519
 520             if (avahi_dns_packet_consume_name(p, buf, sizeof(buf)) < 0)
 521                 return -1;
 522
 523             r->data.ptr.name = avahi_strdup(buf);
 524             break;
 525
 526
 527         case AVAHI_DNS_TYPE_SRV:
 528
 529             if (avahi_dns_packet_consume_uint16(p, &r->data.srv.priority) < 0 ||
 530                 avahi_dns_packet_consume_uint16(p, &r->data.srv.weight) < 0 ||
 531                 avahi_dns_packet_consume_uint16(p, &r->data.srv.port) < 0 ||
 532                 avahi_dns_packet_consume_name(p, buf, sizeof(buf)) < 0)
 533                 return -1;
 534
 535             r->data.srv.name = avahi_strdup(buf);
 536             break;
 537
 538         case AVAHI_DNS_TYPE_HINFO:
 539
 540             if (avahi_dns_packet_consume_string(p, buf, sizeof(buf)) < 0)
 541                 return -1;
 542
 543             r->data.hinfo.cpu = avahi_strdup(buf);
 544
 545             if (avahi_dns_packet_consume_string(p, buf, sizeof(buf)) < 0)
 546                 return -1;
 547
 548             r->data.hinfo.os = avahi_strdup(buf);
 549             break;
 550
 551         case AVAHI_DNS_TYPE_TXT:
 552
 553             if (rdlength > 0) {
 554                 if (avahi_string_list_parse(avahi_dns_packet_get_rptr(p), rdlength, &r->data.txt.string_list) < 0)
 555                     return -1;
 556
 557                 if (avahi_dns_packet_skip(p, rdlength) < 0)
 558                     return -1;
 559             } else
 560                 r->data.txt.string_list = NULL;
 561
 562             break;
 563
 564         case AVAHI_DNS_TYPE_A:
 565
 566 /*             avahi_log_debug("A"); */
 567
 568             if (avahi_dns_packet_consume_bytes(p, &r->data.a.address, sizeof(AvahiIPv4Address)) < 0)
 569                 return -1;
 570
 571             break;
 572
 573         case AVAHI_DNS_TYPE_AAAA:
 574
 575 /*             avahi_log_debug("aaaa"); */
 576
 577             if (avahi_dns_packet_consume_bytes(p, &r->data.aaaa.address, sizeof(AvahiIPv6Address)) < 0)
 578                 return -1;
 579
 580             break;
 581
 582         default:
 583
 584 /*             avahi_log_debug("generic"); */
 585
 586             if (rdlength > 0) {
 587
 588                 r->data.generic.data = avahi_memdup(avahi_dns_packet_get_rptr(p), rdlength);
 589
 590                 if (avahi_dns_packet_skip(p, rdlength) < 0)
 591                     return -1;
 592             }
 593
 594             break;
 595     }
 596
 597     /* Check if we read enough data */
 598     if ((const uint8_t*) avahi_dns_packet_get_rptr(p) - (const uint8_t*) start != rdlength)
 599         return -1;
 600
 601     return 0;
 602 }
 603
 604 AvahiRecord* avahi_dns_packet_consume_record(AvahiDnsPacket *p, int *ret_cache_flush) {
 605     char name[AVAHI_DOMAIN_NAME_MAX];
 606     uint16_t type, class;
 607     uint32_t ttl;
 608     uint16_t rdlength;
 609     AvahiRecord *r = NULL;
 610
 611     assert(p);
 612
 613     if (avahi_dns_packet_consume_name(p, name, sizeof(name)) < 0 ||
 614         avahi_dns_packet_consume_uint16(p, &type) < 0 ||
 615         avahi_dns_packet_consume_uint16(p, &class) < 0 ||
 616         avahi_dns_packet_consume_uint32(p, &ttl) < 0 ||
 617         avahi_dns_packet_consume_uint16(p, &rdlength) < 0 ||
 618         p->rindex + rdlength > p->size)
 619         goto fail;
 620
 621     if (ret_cache_flush)
 622         *ret_cache_flush = !!(class & AVAHI_DNS_CACHE_FLUSH);
 623     class &= ~AVAHI_DNS_CACHE_FLUSH;
 624
 625     if (!(r = avahi_record_new_full(name, class, type, ttl)))
 626         goto fail;
 627
 628     if (parse_rdata(p, r, rdlength) < 0)
 629         goto fail;
 630
 631     if (!avahi_record_is_valid(r))
 632         goto fail;
 633
 634     return r;
 635
 636 fail:
 637     if (r)
 638         avahi_record_unref(r);
 639
 640     return NULL;
 641 }
 642
 643 AvahiKey* avahi_dns_packet_consume_key(AvahiDnsPacket *p, int *ret_unicast_response) {
 644     char name[256];
 645     uint16_t type, class;
 646     AvahiKey *k;
 647
 648     assert(p);
 649
 650     if (avahi_dns_packet_consume_name(p, name, sizeof(name)) < 0 ||
 651         avahi_dns_packet_consume_uint16(p, &type) < 0 ||
 652         avahi_dns_packet_consume_uint16(p, &class) < 0)
 653         return NULL;
 654
 655     if (ret_unicast_response)
 656         *ret_unicast_response = !!(class & AVAHI_DNS_UNICAST_RESPONSE);
 657
 658     class &= ~AVAHI_DNS_UNICAST_RESPONSE;
 659
 660     if (!(k = avahi_key_new(name, class, type)))
 661         return NULL;
 662
 663     if (!avahi_key_is_valid(k)) {
 664         avahi_key_unref(k);
 665         return NULL;
 666     }
 667
 668     return k;
 669 }
 670
 671 uint8_t* avahi_dns_packet_append_key(AvahiDnsPacket *p, AvahiKey *k, int unicast_response) {
 672     uint8_t *t;
 673     size_t size;
 674
 675     assert(p);
 676     assert(k);
 677
 678     size = p->size;
 679
 680     if (!(t = avahi_dns_packet_append_name(p, k->name)) ||
 681         !avahi_dns_packet_append_uint16(p, k->type) ||
 682         !avahi_dns_packet_append_uint16(p, k->clazz | (unicast_response ? AVAHI_DNS_UNICAST_RESPONSE : 0))) {
 683         p->size = size;
 684         return NULL;
 685     }
 686
 687     return t;
 688 }
 689
 690 static int append_rdata(AvahiDnsPacket *p, AvahiRecord *r) {
 691     assert(p);
 692     assert(r);
 693
 694     switch (r->key->type) {
 695
 696         case AVAHI_DNS_TYPE_PTR:
 697         case AVAHI_DNS_TYPE_CNAME:
 698         case AVAHI_DNS_TYPE_NS:
 699
 700             if (!(avahi_dns_packet_append_name(p, r->data.ptr.name)))
 701                 return -1;
 702
 703             break;
 704
 705         case AVAHI_DNS_TYPE_SRV:
 706
 707             if (!avahi_dns_packet_append_uint16(p, r->data.srv.priority) ||
 708                 !avahi_dns_packet_append_uint16(p, r->data.srv.weight) ||
 709                 !avahi_dns_packet_append_uint16(p, r->data.srv.port) ||
 710                 !avahi_dns_packet_append_name(p, r->data.srv.name))
 711                 return -1;
 712
 713             break;
 714
 715         case AVAHI_DNS_TYPE_HINFO:
 716             if (!avahi_dns_packet_append_string(p, r->data.hinfo.cpu) ||
 717                 !avahi_dns_packet_append_string(p, r->data.hinfo.os))
 718                 return -1;
 719
 720             break;
 721
 722         case AVAHI_DNS_TYPE_TXT: {
 723
 724             uint8_t *data;
 725             size_t n;
 726
 727             n = avahi_string_list_serialize(r->data.txt.string_list, NULL, 0);
 728
 729             if (!(data = avahi_dns_packet_extend(p, n)))
 730                 return -1;
 731
 732             avahi_string_list_serialize(r->data.txt.string_list, data, n);
 733             break;
 734         }
 735
 736
 737         case AVAHI_DNS_TYPE_A:
 738
 739             if (!avahi_dns_packet_append_bytes(p, &r->data.a.address, sizeof(r->data.a.address)))
 740                 return -1;
 741
 742             break;
 743
 744         case AVAHI_DNS_TYPE_AAAA:
 745
 746             if (!avahi_dns_packet_append_bytes(p, &r->data.aaaa.address, sizeof(r->data.aaaa.address)))
 747                 return -1;
 748
 749             break;
 750
 751         default:
 752
 753             if (r->data.generic.size)
 754                 if (avahi_dns_packet_append_bytes(p, r->data.generic.data, r->data.generic.size))
 755                     return -1;
 756
 757             break;
 758     }
 759
 760     return 0;
 761 }
 762
 763
 764 uint8_t* avahi_dns_packet_append_record(AvahiDnsPacket *p, AvahiRecord *r, int cache_flush, unsigned max_ttl) {
 765     uint8_t *t, *l, *start;
 766     size_t size;
 767
 768     assert(p);
 769     assert(r);
 770
 771     size = p->size;
 772
 773     if (!(t = avahi_dns_packet_append_name(p, r->key->name)) ||
 774         !avahi_dns_packet_append_uint16(p, r->key->type) ||
 775         !avahi_dns_packet_append_uint16(p, cache_flush ? (r->key->clazz | AVAHI_DNS_CACHE_FLUSH) : (r->key->clazz &~ AVAHI_DNS_CACHE_FLUSH)) ||
 776         !avahi_dns_packet_append_uint32(p, (max_ttl && r->ttl > max_ttl) ? max_ttl : r->ttl) ||
 777         !(l = avahi_dns_packet_append_uint16(p, 0)))
 778         goto fail;
 779
 780     start = avahi_dns_packet_extend(p, 0);
 781
 782     if (append_rdata(p, r) < 0)
 783         goto fail;
 784
 785     size = avahi_dns_packet_extend(p, 0) - start;
 786     assert(size <= 0xFFFF);
 787
 788 /*     avahi_log_debug("appended %u", size); */
 789
 790     l[0] = (uint8_t) ((uint16_t) size >> 8);
 791     l[1] = (uint8_t) ((uint16_t) size);
 792
 793     return t;
 794
 795
 796 fail:
 797     p->size = size;
 798     return NULL;
 799 }
 800
 801 int avahi_dns_packet_is_empty(AvahiDnsPacket *p) {
 802     assert(p);
 803
 804     return p->size <= AVAHI_DNS_PACKET_HEADER_SIZE;
 805 }
 806
 807 size_t avahi_dns_packet_space(AvahiDnsPacket *p) {
 808     assert(p);
 809
 810     assert(p->size <= p->max_size);
 811
 812     return p->max_size - p->size;
 813 }
 814
 815 int avahi_rdata_parse(AvahiRecord *record, const void* rdata, size_t size) {
 816     int ret;
 817     AvahiDnsPacket p;
 818
 819     assert(record);
 820     assert(rdata);
 821
 822     p.data = (void*) rdata;
 823     p.max_size = p.size = size;
 824     p.rindex = 0;
 825     p.name_table = NULL;
 826
 827     ret = parse_rdata(&p, record, size);
 828
 829     assert(!p.name_table);
 830
 831     return ret;
 832 }
 833
 834 size_t avahi_rdata_serialize(AvahiRecord *record, void *rdata, size_t max_size) {
 835     int ret;
 836     AvahiDnsPacket p;
 837
 838     assert(record);
 839     assert(rdata);
 840     assert(max_size > 0);
 841
 842     p.data = (void*) rdata;
 843     p.max_size = max_size;
 844     p.size = p.rindex = 0;
 845     p.name_table = NULL;
 846
 847     ret = append_rdata(&p, record);
 848
 849     if (p.name_table)
 850          avahi_hashmap_free(p.name_table);
 851
 852     if (ret < 0)
 853         return (size_t) -1;
 854
 855     return p.size;
 856 }