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 <sys/types.h>
  32 #include <netinet/in.h>
  33
  34 #include <avahi-common/defs.h>
  35 #include <avahi-common/domain.h>
  36 #include <avahi-common/malloc.h>
  37
  38 #include "dns.h"
  39 #include "log.h"
  40
  41 AvahiDnsPacket* avahi_dns_packet_new(unsigned mtu) {
  42     AvahiDnsPacket *p;
  43     size_t max_size;
  44
  45     if (mtu <= 0)
  46         max_size = AVAHI_DNS_PACKET_SIZE_MAX;
  47     else if (mtu >= AVAHI_DNS_PACKET_EXTRA_SIZE)
  48         max_size = mtu - AVAHI_DNS_PACKET_EXTRA_SIZE;
  49     else
  50         max_size = 0;
  51
  52     if (max_size < AVAHI_DNS_PACKET_HEADER_SIZE)
  53         max_size = AVAHI_DNS_PACKET_HEADER_SIZE;
  54
  55     if (!(p = avahi_malloc(sizeof(AvahiDnsPacket) + max_size)))
  56         return p;
  57
  58     p->size = p->rindex = AVAHI_DNS_PACKET_HEADER_SIZE;
  59     p->max_size = max_size;
  60     p->name_table = NULL;
  61     p->data = NULL;
  62
  63     memset(AVAHI_DNS_PACKET_DATA(p), 0, p->size);
  64     return p;
  65 }
  66
  67 AvahiDnsPacket* avahi_dns_packet_new_query(unsigned mtu) {
  68     AvahiDnsPacket *p;
  69
  70     if (!(p = avahi_dns_packet_new(mtu)))
  71         return NULL;
  72
  73     avahi_dns_packet_set_field(p, AVAHI_DNS_FIELD_FLAGS, AVAHI_DNS_FLAGS(0, 0, 0, 0, 0, 0, 0, 0, 0, 0));
  74     return p;
  75 }
  76
  77 AvahiDnsPacket* avahi_dns_packet_new_response(unsigned mtu, int aa) {
  78     AvahiDnsPacket *p;
  79
  80     if (!(p = avahi_dns_packet_new(mtu)))
  81         return NULL;
  82
  83     avahi_dns_packet_set_field(p, AVAHI_DNS_FIELD_FLAGS, AVAHI_DNS_FLAGS(1, 0, aa, 0, 0, 0, 0, 0, 0, 0));
  84     return p;
  85 }
  86
  87 AvahiDnsPacket* avahi_dns_packet_new_reply(AvahiDnsPacket* p, unsigned mtu, int copy_queries, int aa) {
  88     AvahiDnsPacket *r;
  89     assert(p);
  90
  91     if (!(r = avahi_dns_packet_new_response(mtu, aa)))
  92         return NULL;
  93
  94     if (copy_queries) {
  95         unsigned saved_rindex;
  96         uint32_t n;
  97
  98         saved_rindex = p->rindex;
  99         p->rindex = AVAHI_DNS_PACKET_HEADER_SIZE;
 100
 101         for (n = avahi_dns_packet_get_field(p, AVAHI_DNS_FIELD_QDCOUNT); n > 0; n--) {
 102             AvahiKey *k;
 103             int unicast_response;
 104
 105             if ((k = avahi_dns_packet_consume_key(p, &unicast_response))) {
 106                 avahi_dns_packet_append_key(r, k, unicast_response);
 107                 avahi_key_unref(k);
 108             }
 109         }
 110
 111         p->rindex = saved_rindex;
 112
 113         avahi_dns_packet_set_field(r, AVAHI_DNS_FIELD_QDCOUNT, avahi_dns_packet_get_field(p, AVAHI_DNS_FIELD_QDCOUNT));
 114     }
 115
 116     avahi_dns_packet_set_field(r, AVAHI_DNS_FIELD_ID, avahi_dns_packet_get_field(p, AVAHI_DNS_FIELD_ID));
 117
 118     avahi_dns_packet_set_field(r, AVAHI_DNS_FIELD_FLAGS,
 119                                (avahi_dns_packet_get_field(r, AVAHI_DNS_FIELD_FLAGS) & ~AVAHI_DNS_FLAG_OPCODE) |
 120                                (avahi_dns_packet_get_field(p, AVAHI_DNS_FIELD_FLAGS) & AVAHI_DNS_FLAG_OPCODE));
 121
 122     return r;
 123 }
 124
 125
 126 void avahi_dns_packet_free(AvahiDnsPacket *p) {
 127     assert(p);
 128
 129     if (p->name_table)
 130         avahi_hashmap_free(p->name_table);
 131
 132     avahi_free(p);
 133 }
 134
 135 void avahi_dns_packet_set_field(AvahiDnsPacket *p, unsigned idx, uint16_t v) {
 136     assert(p);
 137     assert(idx < AVAHI_DNS_PACKET_HEADER_SIZE);
 138
 139     ((uint16_t*) AVAHI_DNS_PACKET_DATA(p))[idx] = htons(v);
 140 }
 141
 142 uint16_t avahi_dns_packet_get_field(AvahiDnsPacket *p, unsigned idx) {
 143     assert(p);
 144     assert(idx < AVAHI_DNS_PACKET_HEADER_SIZE);
 145
 146     return ntohs(((uint16_t*) AVAHI_DNS_PACKET_DATA(p))[idx]);
 147 }
 148
 149 void avahi_dns_packet_inc_field(AvahiDnsPacket *p, unsigned idx) {
 150     assert(p);
 151     assert(idx < AVAHI_DNS_PACKET_HEADER_SIZE);
 152
 153     avahi_dns_packet_set_field(p, idx, avahi_dns_packet_get_field(p, idx) + 1);
 154 }
 155
 156 uint8_t* avahi_dns_packet_append_name(AvahiDnsPacket *p, const char *name) {
 157     uint8_t *d, *saved_ptr = NULL;
 158     size_t saved_size;
 159
 160     assert(p);
 161     assert(name);
 162
 163     saved_size = p->size;
 164     saved_ptr = avahi_dns_packet_extend(p, 0);
 165
 166     while (*name) {
 167         uint8_t* prev;
 168         const char *pname;
 169         char label[64], *u;
 170
 171         /* Check whether we can compress this name. */
 172
 173         if (p->name_table && (prev = avahi_hashmap_lookup(p->name_table, name))) {
 174             unsigned idx;
 175
 176             assert(prev >= AVAHI_DNS_PACKET_DATA(p));
 177             idx = (unsigned) (prev - AVAHI_DNS_PACKET_DATA(p));
 178
 179             assert(idx < p->size);
 180
 181             if (idx < 0x4000) {
 182                 uint8_t *t;
 183                 if (!(t = (uint8_t*) avahi_dns_packet_extend(p, sizeof(uint16_t))))
 184                     return NULL;
 185
 186                 t[0] = (uint8_t) ((0xC000 | idx) >> 8);
 187                 t[1] = (uint8_t) idx;
 188                 return saved_ptr;
 189             }
 190         }
 191
 192         pname = name;
 193
 194         if (!(avahi_unescape_label(&name, label, sizeof(label))))
 195             goto fail;
 196
 197         if (!(d = avahi_dns_packet_append_string(p, label)))
 198             goto fail;
 199
 200         if (!p->name_table)
 201             /* This works only for normalized domain names */
 202             p->name_table = avahi_hashmap_new(avahi_string_hash, avahi_string_equal, avahi_free, NULL);
 203
 204         if (!(u = avahi_strdup(pname)))
 205             avahi_log_error("avahi_strdup() failed.");
 206         else
 207             avahi_hashmap_insert(p->name_table, u, d);
 208     }
 209
 210     if (!(d = avahi_dns_packet_extend(p, 1)))
 211         goto fail;
 212
 213     *d = 0;
 214
 215     return saved_ptr;
 216
 217 fail:
 218     p->size = saved_size;
 219     return NULL;
 220 }
 221
 222 uint8_t* avahi_dns_packet_append_uint16(AvahiDnsPacket *p, uint16_t v) {
 223     uint8_t *d;
 224     assert(p);
 225
 226     if (!(d = avahi_dns_packet_extend(p, sizeof(uint16_t))))
 227         return NULL;
 228
 229     d[0] = (uint8_t) (v >> 8);
 230     d[1] = (uint8_t) v;
 231     return d;
 232 }
 233
 234 uint8_t *avahi_dns_packet_append_uint32(AvahiDnsPacket *p, uint32_t v) {
 235     uint8_t *d;
 236     assert(p);
 237
 238     if (!(d = avahi_dns_packet_extend(p, sizeof(uint32_t))))
 239         return NULL;
 240
 241     d[0] = (uint8_t) (v >> 24);
 242     d[1] = (uint8_t) (v >> 16);
 243     d[2] = (uint8_t) (v >> 8);
 244     d[3] = (uint8_t) v;
 245
 246     return d;
 247 }
 248
 249 uint8_t *avahi_dns_packet_append_bytes(AvahiDnsPacket  *p, const void *b, size_t l) {
 250     uint8_t* d;
 251
 252     assert(p);
 253     assert(b);
 254     assert(l);
 255
 256     if (!(d = avahi_dns_packet_extend(p, l)))
 257         return NULL;
 258
 259     memcpy(d, b, l);
 260     return d;
 261 }
 262
 263 uint8_t* avahi_dns_packet_append_string(AvahiDnsPacket *p, const char *s) {
 264     uint8_t* d;
 265     size_t k;
 266
 267     assert(p);
 268     assert(s);
 269
 270     if ((k = strlen(s)) >= 255)
 271         k = 255;
 272
 273     if (!(d = avahi_dns_packet_extend(p, k+1)))
 274         return NULL;
 275
 276     *d = (uint8_t) k;
 277     memcpy(d+1, s, k);
 278
 279     return d;
 280 }
 281
 282 uint8_t *avahi_dns_packet_extend(AvahiDnsPacket *p, size_t l) {
 283     uint8_t *d;
 284
 285     assert(p);
 286
 287     if (p->size+l > p->max_size)
 288         return NULL;
 289
 290     d = AVAHI_DNS_PACKET_DATA(p) + p->size;
 291     p->size += l;
 292
 293     return d;
 294 }
 295
 296 int avahi_dns_packet_check_valid(AvahiDnsPacket *p) {
 297     uint16_t flags;
 298     assert(p);
 299
 300     if (p->size < AVAHI_DNS_PACKET_HEADER_SIZE)
 301         return -1;
 302
 303     flags = avahi_dns_packet_get_field(p, AVAHI_DNS_FIELD_FLAGS);
 304
 305     if (flags & AVAHI_DNS_FLAG_OPCODE)
 306         return -1;
 307
 308     return 0;
 309 }
 310
 311 int avahi_dns_packet_check_valid_multicast(AvahiDnsPacket *p) {
 312     uint16_t flags;
 313     assert(p);
 314
 315     if (avahi_dns_packet_check_valid(p) < 0)
 316         return -1;
 317
 318     flags = avahi_dns_packet_get_field(p, AVAHI_DNS_FIELD_FLAGS);
 319
 320     if (flags & AVAHI_DNS_FLAG_RCODE)
 321         return -1;
 322
 323     return 0;
 324 }
 325
 326 int avahi_dns_packet_is_query(AvahiDnsPacket *p) {
 327     assert(p);
 328
 329     return !(avahi_dns_packet_get_field(p, AVAHI_DNS_FIELD_FLAGS) & AVAHI_DNS_FLAG_QR);
 330 }
 331
 332 static int consume_labels(AvahiDnsPacket *p, unsigned idx, char *ret_name, size_t l) {
 333     int ret = 0;
 334     int compressed = 0;
 335     int first_label = 1;
 336     unsigned label_ptr;
 337     int i;
 338     assert(p && ret_name && l);
 339
 340     for (i = 0; i < AVAHI_DNS_LABELS_MAX; i++) {
 341         uint8_t n;
 342
 343         if (idx+1 > p->size)
 344             return -1;
 345
 346         n = AVAHI_DNS_PACKET_DATA(p)[idx];
 347
 348         if (!n) {
 349             idx++;
 350             if (!compressed)
 351                 ret++;
 352
 353             if (l < 1)
 354                 return -1;
 355             *ret_name = 0;
 356
 357             return ret;
 358
 359         } else if (n <= 63) {
 360             /* Uncompressed label */
 361             idx++;
 362             if (!compressed)
 363                 ret++;
 364
 365             if (idx + n > p->size)
 366                 return -1;
 367
 368             if ((size_t) n + 1 > l)
 369                 return -1;
 370
 371             if (!first_label) {
 372                 *(ret_name++) = '.';
 373                 l--;
 374             } else
 375                 first_label = 0;
 376
 377             if (!(avahi_escape_label((char*) AVAHI_DNS_PACKET_DATA(p) + idx, n, &ret_name, &l)))
 378                 return -1;
 379
 380             idx += n;
 381
 382             if (!compressed)
 383                 ret += n;
 384         } else if ((n & 0xC0) == 0xC0) {
 385             /* Compressed label */
 386
 387             if (idx+2 > p->size)
 388                 return -1;
 389
 390             label_ptr = ((unsigned) (AVAHI_DNS_PACKET_DATA(p)[idx] & ~0xC0)) << 8 | AVAHI_DNS_PACKET_DATA(p)[idx+1];
 391
 392             if ((label_ptr < AVAHI_DNS_PACKET_HEADER_SIZE) || (label_ptr >= idx))
 393                 return -1;
 394
 395             idx = label_ptr;
 396
 397             if (!compressed)
 398                 ret += 2;
 399
 400             compressed = 1;
 401         } else
 402             return -1;
 403     }
 404
 405     return -1;
 406 }
 407
 408 int avahi_dns_packet_consume_name(AvahiDnsPacket *p, char *ret_name, size_t l) {
 409     int r;
 410
 411     if ((r = consume_labels(p, p->rindex, ret_name, l)) < 0)
 412         return -1;
 413
 414     p->rindex += r;
 415     return 0;
 416 }
 417
 418 int avahi_dns_packet_consume_uint16(AvahiDnsPacket *p, uint16_t *ret_v) {
 419     uint8_t *d;
 420
 421     assert(p);
 422     assert(ret_v);
 423
 424     if (p->rindex + sizeof(uint16_t) > p->size)
 425         return -1;
 426
 427     d = (uint8_t*) (AVAHI_DNS_PACKET_DATA(p) + p->rindex);
 428     *ret_v = (d[0] << 8) | d[1];
 429     p->rindex += sizeof(uint16_t);
 430
 431     return 0;
 432 }
 433
 434 int avahi_dns_packet_consume_uint32(AvahiDnsPacket *p, uint32_t *ret_v) {
 435     uint8_t* d;
 436
 437     assert(p);
 438     assert(ret_v);
 439
 440     if (p->rindex + sizeof(uint32_t) > p->size)
 441         return -1;
 442
 443     d = (uint8_t*) (AVAHI_DNS_PACKET_DATA(p) + p->rindex);
 444     *ret_v = (d[0] << 24) | (d[1] << 16) | (d[2] << 8) | d[3];
 445     p->rindex += sizeof(uint32_t);
 446
 447     return 0;
 448 }
 449
 450 int avahi_dns_packet_consume_bytes(AvahiDnsPacket *p, void * ret_data, size_t l) {
 451     assert(p);
 452     assert(ret_data);
 453     assert(l > 0);
 454
 455     if (p->rindex + l > p->size)
 456         return -1;
 457
 458     memcpy(ret_data, AVAHI_DNS_PACKET_DATA(p) + p->rindex, l);
 459     p->rindex += l;
 460
 461     return 0;
 462 }
 463
 464 int avahi_dns_packet_consume_string(AvahiDnsPacket *p, char *ret_string, size_t l) {
 465     size_t k;
 466
 467     assert(p);
 468     assert(ret_string);
 469     assert(l > 0);
 470
 471     if (p->rindex >= p->size)
 472         return -1;
 473
 474     k = AVAHI_DNS_PACKET_DATA(p)[p->rindex];
 475
 476     if (p->rindex+1+k > p->size)
 477         return -1;
 478
 479     if (l > k+1)
 480         l = k+1;
 481
 482     memcpy(ret_string, AVAHI_DNS_PACKET_DATA(p)+p->rindex+1, l-1);
 483     ret_string[l-1] = 0;
 484
 485     p->rindex += 1+k;
 486
 487     return 0;
 488 }
 489
 490 const void* avahi_dns_packet_get_rptr(AvahiDnsPacket *p) {
 491     assert(p);
 492
 493     if (p->rindex > p->size)
 494         return NULL;
 495
 496     return AVAHI_DNS_PACKET_DATA(p) + p->rindex;
 497 }
 498
 499 int avahi_dns_packet_skip(AvahiDnsPacket *p, size_t length) {
 500     assert(p);
 501
 502     if (p->rindex + length > p->size)
 503         return -1;
 504
 505     p->rindex += length;
 506     return 0;
 507 }
 508
 509 static int parse_rdata(AvahiDnsPacket *p, AvahiRecord *r, uint16_t rdlength) {
 510     char buf[AVAHI_DOMAIN_NAME_MAX];
 511     const void* start;
 512
 513     assert(p);
 514     assert(r);
 515
 516     start = avahi_dns_packet_get_rptr(p);
 517
 518     switch (r->key->type) {
 519         case AVAHI_DNS_TYPE_PTR:
 520         case AVAHI_DNS_TYPE_CNAME:
 521         case AVAHI_DNS_TYPE_NS:
 522
 523             if (avahi_dns_packet_consume_name(p, buf, sizeof(buf)) < 0)
 524                 return -1;
 525
 526             r->data.ptr.name = avahi_strdup(buf);
 527             break;
 528
 529
 530         case AVAHI_DNS_TYPE_SRV:
 531
 532             if (avahi_dns_packet_consume_uint16(p, &r->data.srv.priority) < 0 ||
 533                 avahi_dns_packet_consume_uint16(p, &r->data.srv.weight) < 0 ||
 534                 avahi_dns_packet_consume_uint16(p, &r->data.srv.port) < 0 ||
 535                 avahi_dns_packet_consume_name(p, buf, sizeof(buf)) < 0)
 536                 return -1;
 537
 538             r->data.srv.name = avahi_strdup(buf);
 539             break;
 540
 541         case AVAHI_DNS_TYPE_HINFO:
 542
 543             if (avahi_dns_packet_consume_string(p, buf, sizeof(buf)) < 0)
 544                 return -1;
 545
 546             r->data.hinfo.cpu = avahi_strdup(buf);
 547
 548             if (avahi_dns_packet_consume_string(p, buf, sizeof(buf)) < 0)
 549                 return -1;
 550
 551             r->data.hinfo.os = avahi_strdup(buf);
 552             break;
 553
 554         case AVAHI_DNS_TYPE_TXT:
 555
 556             if (rdlength > 0) {
 557                 if (avahi_string_list_parse(avahi_dns_packet_get_rptr(p), rdlength, &r->data.txt.string_list) < 0)
 558                     return -1;
 559
 560                 if (avahi_dns_packet_skip(p, rdlength) < 0)
 561                     return -1;
 562             } else
 563                 r->data.txt.string_list = NULL;
 564
 565             break;
 566
 567         case AVAHI_DNS_TYPE_A:
 568
 569 /*             avahi_log_debug("A"); */
 570
 571             if (avahi_dns_packet_consume_bytes(p, &r->data.a.address, sizeof(AvahiIPv4Address)) < 0)
 572                 return -1;
 573
 574             break;
 575
 576         case AVAHI_DNS_TYPE_AAAA:
 577
 578 /*             avahi_log_debug("aaaa"); */
 579
 580             if (avahi_dns_packet_consume_bytes(p, &r->data.aaaa.address, sizeof(AvahiIPv6Address)) < 0)
 581                 return -1;
 582
 583             break;
 584
 585         default:
 586
 587 /*             avahi_log_debug("generic"); */
 588
 589             if (rdlength > 0) {
 590
 591                 r->data.generic.data = avahi_memdup(avahi_dns_packet_get_rptr(p), rdlength);
 592
 593                 if (avahi_dns_packet_skip(p, rdlength) < 0)
 594                     return -1;
 595             }
 596
 597             break;
 598     }
 599
 600     /* Check if we read enough data */
 601     if ((const uint8_t*) avahi_dns_packet_get_rptr(p) - (const uint8_t*) start != rdlength)
 602         return -1;
 603
 604     return 0;
 605 }
 606
 607 AvahiRecord* avahi_dns_packet_consume_record(AvahiDnsPacket *p, int *ret_cache_flush) {
 608     char name[AVAHI_DOMAIN_NAME_MAX];
 609     uint16_t type, class;
 610     uint32_t ttl;
 611     uint16_t rdlength;
 612     AvahiRecord *r = NULL;
 613
 614     assert(p);
 615
 616     if (avahi_dns_packet_consume_name(p, name, sizeof(name)) < 0 ||
 617         avahi_dns_packet_consume_uint16(p, &type) < 0 ||
 618         avahi_dns_packet_consume_uint16(p, &class) < 0 ||
 619         avahi_dns_packet_consume_uint32(p, &ttl) < 0 ||
 620         avahi_dns_packet_consume_uint16(p, &rdlength) < 0 ||
 621         p->rindex + rdlength > p->size)
 622         goto fail;
 623
 624     if (ret_cache_flush)
 625         *ret_cache_flush = !!(class & AVAHI_DNS_CACHE_FLUSH);
 626     class &= ~AVAHI_DNS_CACHE_FLUSH;
 627
 628     if (!(r = avahi_record_new_full(name, class, type, ttl)))
 629         goto fail;
 630
 631     if (parse_rdata(p, r, rdlength) < 0)
 632         goto fail;
 633
 634     if (!avahi_record_is_valid(r))
 635         goto fail;
 636
 637     return r;
 638
 639 fail:
 640     if (r)
 641         avahi_record_unref(r);
 642
 643     return NULL;
 644 }
 645
 646 AvahiKey* avahi_dns_packet_consume_key(AvahiDnsPacket *p, int *ret_unicast_response) {
 647     char name[256];
 648     uint16_t type, class;
 649     AvahiKey *k;
 650
 651     assert(p);
 652
 653     if (avahi_dns_packet_consume_name(p, name, sizeof(name)) < 0 ||
 654         avahi_dns_packet_consume_uint16(p, &type) < 0 ||
 655         avahi_dns_packet_consume_uint16(p, &class) < 0)
 656         return NULL;
 657
 658     if (ret_unicast_response)
 659         *ret_unicast_response = !!(class & AVAHI_DNS_UNICAST_RESPONSE);
 660
 661     class &= ~AVAHI_DNS_UNICAST_RESPONSE;
 662
 663     if (!(k = avahi_key_new(name, class, type)))
 664         return NULL;
 665
 666     if (!avahi_key_is_valid(k)) {
 667         avahi_key_unref(k);
 668         return NULL;
 669     }
 670
 671     return k;
 672 }
 673
 674 uint8_t* avahi_dns_packet_append_key(AvahiDnsPacket *p, AvahiKey *k, int unicast_response) {
 675     uint8_t *t;
 676     size_t size;
 677
 678     assert(p);
 679     assert(k);
 680
 681     size = p->size;
 682
 683     if (!(t = avahi_dns_packet_append_name(p, k->name)) ||
 684         !avahi_dns_packet_append_uint16(p, k->type) ||
 685         !avahi_dns_packet_append_uint16(p, k->clazz | (unicast_response ? AVAHI_DNS_UNICAST_RESPONSE : 0))) {
 686         p->size = size;
 687         return NULL;
 688     }
 689
 690     return t;
 691 }
 692
 693 static int append_rdata(AvahiDnsPacket *p, AvahiRecord *r) {
 694     assert(p);
 695     assert(r);
 696
 697     switch (r->key->type) {
 698
 699         case AVAHI_DNS_TYPE_PTR:
 700         case AVAHI_DNS_TYPE_CNAME:
 701         case AVAHI_DNS_TYPE_NS:
 702
 703             if (!(avahi_dns_packet_append_name(p, r->data.ptr.name)))
 704                 return -1;
 705
 706             break;
 707
 708         case AVAHI_DNS_TYPE_SRV:
 709
 710             if (!avahi_dns_packet_append_uint16(p, r->data.srv.priority) ||
 711                 !avahi_dns_packet_append_uint16(p, r->data.srv.weight) ||
 712                 !avahi_dns_packet_append_uint16(p, r->data.srv.port) ||
 713                 !avahi_dns_packet_append_name(p, r->data.srv.name))
 714                 return -1;
 715
 716             break;
 717
 718         case AVAHI_DNS_TYPE_HINFO:
 719             if (!avahi_dns_packet_append_string(p, r->data.hinfo.cpu) ||
 720                 !avahi_dns_packet_append_string(p, r->data.hinfo.os))
 721                 return -1;
 722
 723             break;
 724
 725         case AVAHI_DNS_TYPE_TXT: {
 726
 727             uint8_t *data;
 728             size_t n;
 729
 730             n = avahi_string_list_serialize(r->data.txt.string_list, NULL, 0);
 731
 732             if (!(data = avahi_dns_packet_extend(p, n)))
 733                 return -1;
 734
 735             avahi_string_list_serialize(r->data.txt.string_list, data, n);
 736             break;
 737         }
 738
 739
 740         case AVAHI_DNS_TYPE_A:
 741
 742             if (!avahi_dns_packet_append_bytes(p, &r->data.a.address, sizeof(r->data.a.address)))
 743                 return -1;
 744
 745             break;
 746
 747         case AVAHI_DNS_TYPE_AAAA:
 748
 749             if (!avahi_dns_packet_append_bytes(p, &r->data.aaaa.address, sizeof(r->data.aaaa.address)))
 750                 return -1;
 751
 752             break;
 753
 754         default:
 755
 756             if (r->data.generic.size)
 757                 if (avahi_dns_packet_append_bytes(p, r->data.generic.data, r->data.generic.size))
 758                     return -1;
 759
 760             break;
 761     }
 762
 763     return 0;
 764 }
 765
 766
 767 uint8_t* avahi_dns_packet_append_record(AvahiDnsPacket *p, AvahiRecord *r, int cache_flush, unsigned max_ttl) {
 768     uint8_t *t, *l, *start;
 769     size_t size;
 770
 771     assert(p);
 772     assert(r);
 773
 774     size = p->size;
 775
 776     if (!(t = avahi_dns_packet_append_name(p, r->key->name)) ||
 777         !avahi_dns_packet_append_uint16(p, r->key->type) ||
 778         !avahi_dns_packet_append_uint16(p, cache_flush ? (r->key->clazz | AVAHI_DNS_CACHE_FLUSH) : (r->key->clazz &~ AVAHI_DNS_CACHE_FLUSH)) ||
 779         !avahi_dns_packet_append_uint32(p, (max_ttl && r->ttl > max_ttl) ? max_ttl : r->ttl) ||
 780         !(l = avahi_dns_packet_append_uint16(p, 0)))
 781         goto fail;
 782
 783     start = avahi_dns_packet_extend(p, 0);
 784
 785     if (append_rdata(p, r) < 0)
 786         goto fail;
 787
 788     size = avahi_dns_packet_extend(p, 0) - start;
 789     assert(size <= AVAHI_DNS_RDATA_MAX);
 790
 791 /*     avahi_log_debug("appended %u", size); */
 792
 793     l[0] = (uint8_t) ((uint16_t) size >> 8);
 794     l[1] = (uint8_t) ((uint16_t) size);
 795
 796     return t;
 797
 798
 799 fail:
 800     p->size = size;
 801     return NULL;
 802 }
 803
 804 int avahi_dns_packet_is_empty(AvahiDnsPacket *p) {
 805     assert(p);
 806
 807     return p->size <= AVAHI_DNS_PACKET_HEADER_SIZE;
 808 }
 809
 810 size_t avahi_dns_packet_space(AvahiDnsPacket *p) {
 811     assert(p);
 812
 813     assert(p->size <= p->max_size);
 814
 815     return p->max_size - p->size;
 816 }
 817
 818 int avahi_rdata_parse(AvahiRecord *record, const void* rdata, size_t size) {
 819     int ret;
 820     AvahiDnsPacket p;
 821
 822     assert(record);
 823     assert(rdata);
 824
 825     p.data = (void*) rdata;
 826     p.max_size = p.size = size;
 827     p.rindex = 0;
 828     p.name_table = NULL;
 829
 830     ret = parse_rdata(&p, record, size);
 831
 832     assert(!p.name_table);
 833
 834     return ret;
 835 }
 836
 837 size_t avahi_rdata_serialize(AvahiRecord *record, void *rdata, size_t max_size) {
 838     int ret;
 839     AvahiDnsPacket p;
 840
 841     assert(record);
 842     assert(rdata);
 843     assert(max_size > 0);
 844
 845     p.data = (void*) rdata;
 846     p.max_size = max_size;
 847     p.size = p.rindex = 0;
 848     p.name_table = NULL;
 849
 850     ret = append_rdata(&p, record);
 851
 852     if (p.name_table)
 853          avahi_hashmap_free(p.name_table);
 854
 855     if (ret < 0)
 856         return (size_t) -1;
 857
 858     return p.size;
 859 }