gweb/gresolv.c

   1 /*
   2  *
   3  *  Resolver library with GLib integration
   4  *
   5  *  Copyright (C) 2009-2013  Intel Corporation. All rights reserved.
   6  *
   7  *  This program is free software; you can redistribute it and/or modify
   8  *  it under the terms of the GNU General Public License version 2 as
   9  *  published by the Free Software Foundation.
  10  *
  11  *  This program is distributed in the hope that it will be useful,
  12  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  *  GNU General Public License for more details.
  15  *
  16  *  You should have received a copy of the GNU General Public License
  17  *  along with this program; if not, write to the Free Software
  18  *  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  19  *
  20  */
  21
  22 #ifdef HAVE_CONFIG_H
  23 #include <config.h>
  24 #endif
  25
  26 #include <errno.h>
  27 #include <unistd.h>
  28 #include <stdarg.h>
  29 #include <string.h>
  30 #include <stdlib.h>
  31 #include <resolv.h>
  32 #include <sys/types.h>
  33 #include <sys/socket.h>
  34 #include <netdb.h>
  35 #include <arpa/inet.h>
  36 #include <arpa/nameser.h>
  37 #include <net/if.h>
  38
  39 #include "gresolv.h"
  40
  41 struct sort_result {
  42         int precedence;
  43         int src_scope;
  44         int dst_scope;
  45         int src_label;
  46         int dst_label;
  47         bool reachable;
  48         union {
  49                 struct sockaddr sa;
  50                 struct sockaddr_in sin;
  51                 struct sockaddr_in6 sin6;
  52         } src;
  53         union {
  54                 struct sockaddr sa;
  55                 struct sockaddr_in sin;
  56                 struct sockaddr_in6 sin6;
  57         } dst;
  58 };
  59
  60 struct resolv_query;
  61
  62 struct resolv_lookup {
  63         GResolv *resolv;
  64         guint id;
  65
  66         int nr_results;
  67         struct sort_result *results;
  68
  69         struct resolv_query *ipv4_query;
  70         struct resolv_query *ipv6_query;
  71
  72         guint ipv4_status;
  73         guint ipv6_status;
  74
  75         GResolvResultFunc result_func;
  76         gpointer result_data;
  77 };
  78
  79 struct resolv_query {
  80         GResolv *resolv;
  81
  82         int nr_ns;
  83         guint timeout;
  84
  85         uint16_t msgid;
  86
  87         struct resolv_lookup *lookup;
  88 };
  89
  90 struct resolv_nameserver {
  91         GResolv *resolv;
  92
  93         char *address;
  94         uint16_t port;
  95         unsigned long flags;
  96
  97         GIOChannel *udp_channel;
  98         guint udp_watch;
  99 };
 100
 101 struct _GResolv {
 102         int ref_count;
 103
 104         int result_family;
 105
 106         guint next_lookup_id;
 107         GQueue *lookup_queue;
 108         GQueue *query_queue;
 109
 110         int index;
 111         GList *nameserver_list;
 112
 113         struct __res_state res;
 114
 115         GResolvDebugFunc debug_func;
 116         gpointer debug_data;
 117 };
 118
 119 #define debug(resolv, format, arg...)                           \
 120         _debug(resolv, __FILE__, __func__, format, ## arg)
 121
 122 static void _debug(GResolv *resolv, const char *file, const char *caller,
 123                                                 const char *format, ...)
 124 {
 125         char str[256];
 126         va_list ap;
 127         int len;
 128
 129         if (!resolv->debug_func)
 130                 return;
 131
 132         va_start(ap, format);
 133
 134         if ((len = snprintf(str, sizeof(str), "%s:%s() resolv %p ",
 135                                                 file, caller, resolv)) > 0) {
 136                 if (vsnprintf(str + len, sizeof(str) - len, format, ap) > 0)
 137                         resolv->debug_func(str, resolv->debug_data);
 138         }
 139
 140         va_end(ap);
 141 }
 142
 143 static void destroy_query(struct resolv_query *query)
 144 {
 145         debug(query->resolv, "query %p timeout %d", query, query->timeout);
 146
 147         if (query->timeout > 0)
 148                 g_source_remove(query->timeout);
 149
 150         g_free(query);
 151 }
 152
 153 static void destroy_lookup(struct resolv_lookup *lookup)
 154 {
 155         debug(lookup->resolv, "lookup %p id %d ipv4 %p ipv6 %p",
 156                 lookup, lookup->id, lookup->ipv4_query, lookup->ipv6_query);
 157
 158         if (lookup->ipv4_query) {
 159                 g_queue_remove(lookup->resolv->query_queue,
 160                                                 lookup->ipv4_query);
 161                 destroy_query(lookup->ipv4_query);
 162         }
 163
 164         if (lookup->ipv6_query) {
 165                 g_queue_remove(lookup->resolv->query_queue,
 166                                                 lookup->ipv6_query);
 167                 destroy_query(lookup->ipv6_query);
 168         }
 169
 170         g_free(lookup->results);
 171         g_free(lookup);
 172 }
 173
 174 static void find_srcaddr(struct sort_result *res)
 175 {
 176         socklen_t sl = sizeof(res->src);
 177         int fd;
 178
 179         fd = socket(res->dst.sa.sa_family, SOCK_DGRAM | SOCK_CLOEXEC,
 180                         IPPROTO_IP);
 181         if (fd < 0)
 182                 return;
 183
 184         if (connect(fd, &res->dst.sa, sizeof(res->dst)) < 0) {
 185                 close(fd);
 186                 return;
 187         }
 188
 189         if (getsockname(fd, &res->src.sa, &sl) < 0) {
 190                 close(fd);
 191                 return;
 192         }
 193
 194         res->reachable = true;
 195         close(fd);
 196 }
 197
 198 struct gai_table
 199 {
 200         unsigned char addr[NS_IN6ADDRSZ];
 201         int mask;
 202         int value;
 203 };
 204
 205 static const struct gai_table gai_labels[] = {
 206         {
 207                 .addr = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 208                           0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01 },
 209                 .mask = 128,
 210                 .value = 0,
 211         }, {
 212                 .addr = { 0x20, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 213                           0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
 214                 .mask = 16,
 215                 .value = 2,
 216         }, {
 217                 .addr = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 218                           0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
 219                 .mask = 96,
 220                 .value = 3,
 221         }, {
 222                 .addr = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 223                           0x00, 0x00, 0xff, 0xff, 0x00, 0x00, 0x00, 0x00 },
 224                 .mask = 96,
 225                 .value = 4,
 226         }, {
 227                 /* Variations from RFC 3484, matching glibc behaviour */
 228                 .addr = { 0xfe, 0xc0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 229                           0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
 230                 .mask = 10,
 231                 .value = 5,
 232         }, {
 233                 .addr = { 0xfc, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 234                           0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
 235                 .mask = 7,
 236                 .value = 6,
 237         }, {
 238                 .addr = { 0x20, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 239                           0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
 240                 .mask = 32,
 241                 .value = 7,
 242         }, {
 243                 /* catch-all */
 244                 .addr = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 245                           0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
 246                 .mask = 0,
 247                 .value = 1,
 248         }
 249 };
 250
 251 static const struct gai_table gai_precedences[] = {
 252         {
 253                 .addr = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 254                           0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01 },
 255                 .mask = 128,
 256                 .value = 50,
 257         }, {
 258                 .addr = { 0x20, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 259                           0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
 260                 .mask = 16,
 261                 .value = 30,
 262         }, {
 263                 .addr = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 264                           0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
 265                 .mask = 96,
 266                 .value = 20,
 267         }, {
 268                 .addr = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 269                           0x00, 0x00, 0xff, 0xff, 0x00, 0x00, 0x00, 0x00 },
 270                 .mask = 96,
 271                 .value = 10,
 272         }, {
 273                 .addr = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 274                           0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
 275                 .mask = 0,
 276                 .value = 40,
 277         }
 278 };
 279
 280 static unsigned char v4mapped[] = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 281                                     0x00, 0x00, 0xff, 0xff, 0x00, 0x00, 0x00, 0x00 };
 282
 283 static bool mask_compare(const unsigned char *one,
 284                                         const unsigned char *two, int mask)
 285 {
 286         if (mask > 8) {
 287                 if (memcmp(one, two, mask / 8))
 288                         return false;
 289                 one += mask / 8;
 290                 two += mask / 8;
 291                 mask %= 8;
 292         }
 293
 294         if (mask && ((*one ^ *two) >> (8 - mask)))
 295                 return false;
 296
 297         return true;
 298 }
 299
 300 static int match_gai_table(struct sockaddr *sa, const struct gai_table *tbl)
 301 {
 302         struct sockaddr_in *sin = (void *)sa;
 303         struct sockaddr_in6 *sin6 = (void *)sa;
 304         void *addr;
 305
 306         if (sa->sa_family == AF_INET) {
 307                 addr = v4mapped;
 308                 memcpy(v4mapped+12, &sin->sin_addr, NS_INADDRSZ);
 309         } else
 310                 addr = &sin6->sin6_addr;
 311
 312         while (1) {
 313                 if (mask_compare(addr, tbl->addr, tbl->mask))
 314                         return tbl->value;
 315                 tbl++;
 316         }
 317 }
 318
 319 #define DQUAD(_a,_b,_c,_d) ( ((_a)<<24) | ((_b)<<16) | ((_c)<<8) | (_d) )
 320 #define V4MATCH(addr, a,b,c,d, m) ( ((addr) ^ DQUAD(a,b,c,d)) >> (32 - (m)) )
 321
 322 #define RFC3484_SCOPE_LINK      2
 323 #define RFC3484_SCOPE_SITE      5
 324 #define RFC3484_SCOPE_GLOBAL    14
 325
 326 static int addr_scope(struct sockaddr *sa)
 327 {
 328         if (sa->sa_family == AF_INET) {
 329                 struct sockaddr_in *sin = (void *)sa;
 330                 guint32 addr = ntohl(sin->sin_addr.s_addr);
 331
 332                 if (V4MATCH(addr, 169,254,0,0, 16) ||
 333                                         V4MATCH(addr, 127,0,0,0, 8))
 334                         return RFC3484_SCOPE_LINK;
 335
 336                 /* Site-local */
 337                 if (V4MATCH(addr, 10,0,0,0, 8) ||
 338                                 V4MATCH(addr, 172,16,0,0, 12) ||
 339                                 V4MATCH(addr, 192,168,0,0, 16))
 340                         return RFC3484_SCOPE_SITE;
 341
 342                 /* Global */
 343                 return RFC3484_SCOPE_GLOBAL;
 344         } else {
 345                 struct sockaddr_in6 *sin6 = (void *)sa;
 346
 347                 /* Multicast addresses have a 4-bit scope field */
 348                 if (IN6_IS_ADDR_MULTICAST(&sin6->sin6_addr))
 349                         return sin6->sin6_addr.s6_addr[1] & 0xf;
 350
 351                 if (IN6_IS_ADDR_LINKLOCAL(&sin6->sin6_addr) ||
 352                                 IN6_IS_ADDR_LOOPBACK(&sin6->sin6_addr))
 353                         return RFC3484_SCOPE_LINK;
 354
 355                 if (IN6_IS_ADDR_SITELOCAL(&sin6->sin6_addr))
 356                         return RFC3484_SCOPE_SITE;
 357
 358                 return RFC3484_SCOPE_GLOBAL;
 359         }
 360 }
 361
 362 static int rfc3484_compare(const void *__one, const void *__two)
 363 {
 364         const struct sort_result *one = __one;
 365         const struct sort_result *two = __two;
 366
 367         /* Rule 1: Avoid unusable destinations */
 368         if (one->reachable && !two->reachable)
 369                 return -1;
 370         else if (two->reachable && !one->reachable)
 371                 return 1;
 372
 373         /* Rule 2: Prefer matching scope */
 374         if (one->dst_scope == one->src_scope &&
 375                                 two->dst_scope != two->src_scope)
 376                 return -1;
 377         else if (two->dst_scope == two->src_scope &&
 378                                 one->dst_scope != one->src_scope)
 379                 return 1;
 380
 381         /* Rule 3: Avoid deprecated addresses */
 382
 383         /* Rule 4: Prefer home addresses */
 384
 385         /* Rule 5: Prefer matching label */
 386         if (one->dst_label == one->src_label &&
 387                                 two->dst_label != two->src_label)
 388                 return -1;
 389         else if (two->dst_label == two->src_label &&
 390                                 one->dst_label != one->src_label)
 391                 return 1;
 392
 393         /* Rule 6: Prefer higher precedence */
 394         if (one->precedence > two->precedence)
 395                 return -1;
 396         else if (two->precedence > one->precedence)
 397                 return 1;
 398
 399         /* Rule 7: Prefer native transport */
 400
 401         /* Rule 8: Prefer smaller scope */
 402         if (one->dst_scope != two->dst_scope)
 403                 return one->dst_scope - two->dst_scope;
 404
 405         /* Rule 9: Use longest matching prefix */
 406         if (one->dst.sa.sa_family == AF_INET) {
 407                 /*
 408                  * Rule 9 is meaningless and counterproductive for Legacy IP
 409                  * unless perhaps we can tell that it's actually on the local
 410                  * subnet. But we don't (yet) have local interface config
 411                  * information, so do nothing here for Legacy IP for now.
 412                  */
 413         } else {
 414                 int i;
 415
 416                 for (i = 0; i < 4; i++) {
 417                         guint32 cmp_one, cmp_two;
 418
 419                         cmp_one = one->src.sin6.sin6_addr.s6_addr32[i] ^
 420                                         one->dst.sin6.sin6_addr.s6_addr32[i];
 421                         cmp_two = two->src.sin6.sin6_addr.s6_addr32[i] ^
 422                                         two->dst.sin6.sin6_addr.s6_addr32[i];
 423
 424                         if (!cmp_two && !cmp_one)
 425                                 continue;
 426
 427                         if (cmp_one && !cmp_two)
 428                                 return 1;
 429                         if (cmp_two && !cmp_one)
 430                                 return -1;
 431
 432                         /* g_bit_storage() is effectively fls() */
 433                         cmp_one = g_bit_storage(ntohl(cmp_one));
 434                         cmp_two = g_bit_storage(ntohl(cmp_two));
 435
 436                         if (cmp_one == cmp_two)
 437                                 break;
 438
 439                         return cmp_one - cmp_two;
 440                 }
 441         }
 442
 443
 444         /* Rule 10: Otherwise, leave the order unchanged */
 445         if (one < two)
 446                 return -1;
 447         else
 448                 return 1;
 449 }
 450
 451 static void rfc3484_sort_results(struct resolv_lookup *lookup)
 452 {
 453         int i;
 454
 455         for (i = 0; i < lookup->nr_results; i++) {
 456                 struct sort_result *res = &lookup->results[i];
 457                 find_srcaddr(res);
 458                 res->precedence = match_gai_table(&res->dst.sa,
 459                                                         gai_precedences);
 460                 res->dst_label = match_gai_table(&res->dst.sa, gai_labels);
 461                 res->src_label = match_gai_table(&res->src.sa, gai_labels);
 462                 res->dst_scope = addr_scope(&res->dst.sa);
 463                 res->src_scope = addr_scope(&res->src.sa);
 464         }
 465
 466         qsort(lookup->results, lookup->nr_results,
 467                         sizeof(struct sort_result), rfc3484_compare);
 468 }
 469
 470 static void sort_and_return_results(struct resolv_lookup *lookup)
 471 {
 472         char buf[INET6_ADDRSTRLEN + 1];
 473         GResolvResultStatus status;
 474         char **results = g_try_new0(char *, lookup->nr_results + 1);
 475         GResolvResultFunc result_func = lookup->result_func;
 476         void *result_data = lookup->result_data;
 477         int i, n = 0;
 478
 479         if (!results)
 480                 return;
 481
 482         memset(buf, 0, INET6_ADDRSTRLEN + 1);
 483
 484         rfc3484_sort_results(lookup);
 485
 486         for (i = 0; i < lookup->nr_results; i++) {
 487                 if (lookup->results[i].dst.sa.sa_family == AF_INET) {
 488                         if (!inet_ntop(AF_INET,
 489                                         &lookup->results[i].dst.sin.sin_addr,
 490                                         buf, sizeof(buf) - 1))
 491                                 continue;
 492                 } else if (lookup->results[i].dst.sa.sa_family == AF_INET6) {
 493                         if (!inet_ntop(AF_INET6,
 494                                         &lookup->results[i].dst.sin6.sin6_addr,
 495                                         buf, sizeof(buf) - 1))
 496                                 continue;
 497                 } else
 498                         continue;
 499
 500                 results[n++] = g_strdup(buf);
 501         }
 502
 503         results[n++] = NULL;
 504
 505         if (lookup->resolv->result_family == AF_INET)
 506                 status = lookup->ipv4_status;
 507         else if (lookup->resolv->result_family == AF_INET6)
 508                 status = lookup->ipv6_status;
 509         else {
 510                 if (lookup->ipv6_status == G_RESOLV_RESULT_STATUS_SUCCESS)
 511                         status = lookup->ipv6_status;
 512                 else
 513                         status = lookup->ipv4_status;
 514         }
 515
 516         debug(lookup->resolv, "lookup %p received %d results", lookup, n);
 517
 518         g_queue_remove(lookup->resolv->lookup_queue, lookup);
 519         destroy_lookup(lookup);
 520
 521         result_func(status, results, result_data);
 522
 523         g_strfreev(results);
 524 }
 525
 526 static gboolean query_timeout(gpointer user_data)
 527 {
 528         struct resolv_query *query = user_data;
 529         struct resolv_lookup *lookup = query->lookup;
 530         GResolv *resolv = query->resolv;
 531
 532         query->timeout = 0;
 533
 534         if (query == lookup->ipv4_query) {
 535                 lookup->ipv4_status = G_RESOLV_RESULT_STATUS_NO_RESPONSE;
 536                 lookup->ipv4_query = NULL;
 537         } else if (query == lookup->ipv6_query) {
 538                 lookup->ipv6_status = G_RESOLV_RESULT_STATUS_NO_RESPONSE;
 539                 lookup->ipv6_query = NULL;
 540         }
 541
 542         g_queue_remove(resolv->query_queue, query);
 543         destroy_query(query);
 544
 545         if (!lookup->ipv4_query && !lookup->ipv6_query)
 546                 sort_and_return_results(lookup);
 547
 548         return FALSE;
 549 }
 550
 551 static void free_nameserver(struct resolv_nameserver *nameserver)
 552 {
 553         if (!nameserver)
 554                 return;
 555
 556         if (nameserver->udp_watch > 0)
 557                 g_source_remove(nameserver->udp_watch);
 558
 559         if (nameserver->udp_channel) {
 560                 g_io_channel_shutdown(nameserver->udp_channel, TRUE, NULL);
 561                 g_io_channel_unref(nameserver->udp_channel);
 562         }
 563
 564         g_free(nameserver->address);
 565         g_free(nameserver);
 566 }
 567
 568 static void flush_nameservers(GResolv *resolv)
 569 {
 570         GList *list;
 571
 572         for (list = g_list_first(resolv->nameserver_list);
 573                                         list; list = g_list_next(list))
 574                 free_nameserver(list->data);
 575
 576         g_list_free(resolv->nameserver_list);
 577         resolv->nameserver_list = NULL;
 578 }
 579
 580 static int send_query(GResolv *resolv, const unsigned char *buf, int len)
 581 {
 582         GList *list;
 583         int nr_ns;
 584
 585         if (!resolv->nameserver_list)
 586                 return -ENOENT;
 587
 588         for (list = g_list_first(resolv->nameserver_list), nr_ns = 0;
 589                                 list; list = g_list_next(list), nr_ns++) {
 590                 struct resolv_nameserver *nameserver = list->data;
 591                 int sk, sent;
 592
 593                 if (!nameserver->udp_channel)
 594                         continue;
 595
 596                 sk = g_io_channel_unix_get_fd(nameserver->udp_channel);
 597
 598                 sent = send(sk, buf, len, 0);
 599                 if (sent < 0)
 600                         continue;
 601         }
 602
 603         return nr_ns;
 604 }
 605
 606 static gint compare_lookup_id(gconstpointer a, gconstpointer b)
 607 {
 608         const struct resolv_lookup *lookup = a;
 609         guint id = GPOINTER_TO_UINT(b);
 610
 611         if (lookup->id < id)
 612                 return -1;
 613
 614         if (lookup->id > id)
 615                 return 1;
 616
 617         return 0;
 618 }
 619
 620 static gint compare_query_msgid(gconstpointer a, gconstpointer b)
 621 {
 622         const struct resolv_query *query = a;
 623         uint16_t msgid = GPOINTER_TO_UINT(b);
 624
 625         if (query->msgid < msgid)
 626                 return -1;
 627
 628         if (query->msgid > msgid)
 629                 return 1;
 630
 631         return 0;
 632 }
 633
 634 static void add_result(struct resolv_lookup *lookup, int family,
 635                                                         const void *data)
 636 {
 637         int n = lookup->nr_results++;
 638         lookup->results = g_try_realloc(lookup->results,
 639                                         sizeof(struct sort_result) * (n + 1));
 640         if (!lookup->results)
 641                 return;
 642
 643         memset(&lookup->results[n], 0, sizeof(struct sort_result));
 644
 645         lookup->results[n].dst.sa.sa_family = family;
 646         if (family == AF_INET)
 647                 memcpy(&lookup->results[n].dst.sin.sin_addr,
 648                                                 data, NS_INADDRSZ);
 649         else
 650                 memcpy(&lookup->results[n].dst.sin6.sin6_addr,
 651                                                 data, NS_IN6ADDRSZ);
 652 }
 653
 654 static void parse_response(struct resolv_nameserver *nameserver,
 655                                         const unsigned char *buf, int len)
 656 {
 657         GResolv *resolv = nameserver->resolv;
 658         GResolvResultStatus status;
 659         struct resolv_query *query;
 660         struct resolv_lookup *lookup;
 661         GList *list;
 662         ns_msg msg;
 663         ns_rr rr;
 664         int i, rcode, count;
 665
 666         debug(resolv, "response from %s", nameserver->address);
 667
 668         if (ns_initparse(buf, len, &msg) < 0)
 669                 return;
 670
 671         list = g_queue_find_custom(resolv->query_queue,
 672                         GUINT_TO_POINTER(ns_msg_id(msg)), compare_query_msgid);
 673         if (!list)
 674                 return;
 675
 676         rcode = ns_msg_getflag(msg, ns_f_rcode);
 677         count = ns_msg_count(msg, ns_s_an);
 678
 679         debug(resolv, "msg id: 0x%04x rcode: %d count: %d",
 680                                         ns_msg_id(msg), rcode, count);
 681
 682         switch (rcode) {
 683         case ns_r_noerror:
 684                 status = G_RESOLV_RESULT_STATUS_SUCCESS;
 685                 break;
 686         case ns_r_formerr:
 687                 status = G_RESOLV_RESULT_STATUS_FORMAT_ERROR;
 688                 break;
 689         case ns_r_servfail:
 690                 status = G_RESOLV_RESULT_STATUS_SERVER_FAILURE;
 691                 break;
 692         case ns_r_nxdomain:
 693                 status = G_RESOLV_RESULT_STATUS_NAME_ERROR;
 694                 break;
 695         case ns_r_notimpl:
 696                 status = G_RESOLV_RESULT_STATUS_NOT_IMPLEMENTED;
 697                 break;
 698         case ns_r_refused:
 699                 status = G_RESOLV_RESULT_STATUS_REFUSED;
 700                 break;
 701         default:
 702                 status = G_RESOLV_RESULT_STATUS_ERROR;
 703                 break;
 704         }
 705
 706         query = list->data;
 707         query->nr_ns--;
 708
 709         lookup = query->lookup;
 710
 711         if (query == lookup->ipv6_query)
 712                 lookup->ipv6_status = status;
 713         else if (query == lookup->ipv4_query)
 714                 lookup->ipv4_status = status;
 715
 716         for (i = 0; i < count; i++) {
 717                 if (ns_parserr(&msg, ns_s_an, i, &rr) < 0)
 718                         continue;
 719
 720                 if (ns_rr_class(rr) != ns_c_in)
 721                         continue;
 722
 723                 g_assert(offsetof(struct sockaddr_in, sin_addr) ==
 724                                 offsetof(struct sockaddr_in6, sin6_flowinfo));
 725
 726                 if (ns_rr_type(rr) == ns_t_a &&
 727                                         ns_rr_rdlen(rr) == NS_INADDRSZ) {
 728                         add_result(lookup, AF_INET, ns_rr_rdata(rr));
 729                 } else if (ns_rr_type(rr) == ns_t_aaaa &&
 730                                         ns_rr_rdlen(rr) == NS_IN6ADDRSZ) {
 731                         add_result(lookup, AF_INET6, ns_rr_rdata(rr));
 732                 }
 733         }
 734
 735         if (status != G_RESOLV_RESULT_STATUS_SUCCESS && query->nr_ns > 0)
 736                 return;
 737
 738         if (query == lookup->ipv6_query)
 739                 lookup->ipv6_query = NULL;
 740         else
 741                 lookup->ipv4_query = NULL;
 742
 743         g_queue_remove(resolv->query_queue, query);
 744         destroy_query(query);
 745
 746         if (!lookup->ipv4_query && !lookup->ipv6_query)
 747                 sort_and_return_results(lookup);
 748 }
 749
 750 static gboolean received_udp_data(GIOChannel *channel, GIOCondition cond,
 751                                                         gpointer user_data)
 752 {
 753         struct resolv_nameserver *nameserver = user_data;
 754         unsigned char buf[4096];
 755         int sk, len;
 756
 757         if (cond & (G_IO_NVAL | G_IO_ERR | G_IO_HUP)) {
 758                 nameserver->udp_watch = 0;
 759                 return FALSE;
 760         }
 761
 762         sk = g_io_channel_unix_get_fd(nameserver->udp_channel);
 763
 764         len = recv(sk, buf, sizeof(buf), 0);
 765         if (len < 12)
 766                 return TRUE;
 767
 768         parse_response(nameserver, buf, len);
 769
 770         return TRUE;
 771 }
 772
 773 static int connect_udp_channel(struct resolv_nameserver *nameserver)
 774 {
 775         struct addrinfo hints, *rp;
 776         char portnr[6];
 777         int err, sk;
 778
 779         memset(&hints, 0, sizeof(hints));
 780         hints.ai_family = AF_UNSPEC;
 781         hints.ai_socktype = SOCK_DGRAM;
 782         hints.ai_flags = AI_PASSIVE | AI_NUMERICSERV | AI_NUMERICHOST;
 783
 784         sprintf(portnr, "%d", nameserver->port);
 785         err = getaddrinfo(nameserver->address, portnr, &hints, &rp);
 786         if (err)
 787                 return -EINVAL;
 788
 789         /*
 790          * Do not blindly copy this code elsewhere; it doesn't loop over the
 791          * results using ->ai_next as it should. That's OK in *this* case
 792          * because it was a numeric lookup; we *know* there's only one.
 793          */
 794         if (!rp)
 795                 return -EINVAL;
 796
 797         sk = socket(rp->ai_family, rp->ai_socktype, rp->ai_protocol);
 798         if (sk < 0) {
 799                 freeaddrinfo(rp);
 800                 return -EIO;
 801         }
 802
 803         /*
 804          * If nameserver points to localhost ip, their is no need to
 805          * bind the socket on any interface.
 806          */
 807         if (nameserver->resolv->index > 0 &&
 808                         strncmp(nameserver->address, "127.0.0.1", 9) != 0) {
 809                 char interface[IF_NAMESIZE];
 810
 811                 memset(interface, 0, IF_NAMESIZE);
 812                 if (if_indextoname(nameserver->resolv->index, interface)) {
 813                         if (setsockopt(sk, SOL_SOCKET, SO_BINDTODEVICE,
 814                                                 interface, IF_NAMESIZE) < 0) {
 815                                 close(sk);
 816                                 freeaddrinfo(rp);
 817                                 return -EIO;
 818                         }
 819                 }
 820         }
 821
 822         if (connect(sk, rp->ai_addr, rp->ai_addrlen) < 0) {
 823                 close(sk);
 824                 freeaddrinfo(rp);
 825                 return -EIO;
 826         }
 827
 828         freeaddrinfo(rp);
 829
 830         nameserver->udp_channel = g_io_channel_unix_new(sk);
 831         if (!nameserver->udp_channel) {
 832                 close(sk);
 833                 return -ENOMEM;
 834         }
 835
 836         g_io_channel_set_close_on_unref(nameserver->udp_channel, TRUE);
 837
 838         nameserver->udp_watch = g_io_add_watch(nameserver->udp_channel,
 839                                 G_IO_IN | G_IO_NVAL | G_IO_ERR | G_IO_HUP,
 840                                 received_udp_data, nameserver);
 841
 842         return 0;
 843 }
 844
 845 GResolv *g_resolv_new(int index)
 846 {
 847         GResolv *resolv;
 848
 849         if (index < 0)
 850                 return NULL;
 851
 852         resolv = g_try_new0(GResolv, 1);
 853         if (!resolv)
 854                 return NULL;
 855
 856         resolv->ref_count = 1;
 857
 858         resolv->result_family = AF_UNSPEC;
 859
 860         resolv->next_lookup_id = 1;
 861
 862         resolv->query_queue = g_queue_new();
 863         if (!resolv->query_queue) {
 864                 g_free(resolv);
 865                 return NULL;
 866         }
 867
 868         resolv->lookup_queue = g_queue_new();
 869         if (!resolv->lookup_queue) {
 870                 g_queue_free(resolv->query_queue);
 871                 g_free(resolv);
 872                 return NULL;
 873         }
 874
 875         resolv->index = index;
 876         resolv->nameserver_list = NULL;
 877
 878         res_ninit(&resolv->res);
 879
 880         return resolv;
 881 }
 882
 883 GResolv *g_resolv_ref(GResolv *resolv)
 884 {
 885         if (!resolv)
 886                 return NULL;
 887
 888         __sync_fetch_and_add(&resolv->ref_count, 1);
 889
 890         return resolv;
 891 }
 892
 893 void g_resolv_unref(GResolv *resolv)
 894 {
 895         struct resolv_query *query;
 896         struct resolv_lookup *lookup;
 897
 898         if (!resolv)
 899                 return;
 900
 901         if (__sync_fetch_and_sub(&resolv->ref_count, 1) != 1)
 902                 return;
 903
 904         while ((lookup = g_queue_pop_head(resolv->lookup_queue))) {
 905                 debug(resolv, "lookup %p id %d", lookup, lookup->id);
 906                 destroy_lookup(lookup);
 907         }
 908
 909         while ((query = g_queue_pop_head(resolv->query_queue))) {
 910                 debug(resolv, "query %p", query);
 911                 destroy_query(query);
 912         }
 913
 914         g_queue_free(resolv->query_queue);
 915         g_queue_free(resolv->lookup_queue);
 916
 917         flush_nameservers(resolv);
 918
 919         res_nclose(&resolv->res);
 920
 921         g_free(resolv);
 922 }
 923
 924 void g_resolv_set_debug(GResolv *resolv, GResolvDebugFunc func,
 925                                                 gpointer user_data)
 926 {
 927         if (!resolv)
 928                 return;
 929
 930         resolv->debug_func = func;
 931         resolv->debug_data = user_data;
 932 }
 933
 934 bool g_resolv_add_nameserver(GResolv *resolv, const char *address,
 935                                         uint16_t port, unsigned long flags)
 936 {
 937         struct resolv_nameserver *nameserver;
 938
 939         if (!resolv)
 940                 return false;
 941
 942         nameserver = g_try_new0(struct resolv_nameserver, 1);
 943         if (!nameserver)
 944                 return false;
 945
 946         nameserver->address = g_strdup(address);
 947         nameserver->port = port;
 948         nameserver->flags = flags;
 949         nameserver->resolv = resolv;
 950
 951         debug(resolv, "");
 952         if (connect_udp_channel(nameserver) < 0) {
 953                 free_nameserver(nameserver);
 954                 return false;
 955         }
 956         debug(resolv, "");
 957
 958         resolv->nameserver_list = g_list_append(resolv->nameserver_list,
 959                                                                 nameserver);
 960
 961         debug(resolv, "setting nameserver %s", address);
 962
 963         return true;
 964 }
 965
 966 void g_resolv_flush_nameservers(GResolv *resolv)
 967 {
 968         if (!resolv)
 969                 return;
 970
 971         flush_nameservers(resolv);
 972 }
 973
 974 static gint add_query(struct resolv_lookup *lookup, const char *hostname, int type)
 975 {
 976         struct resolv_query *query = g_try_new0(struct resolv_query, 1);
 977         unsigned char buf[4096];
 978         int len;
 979
 980         if (!query)
 981                 return -ENOMEM;
 982
 983         len = res_mkquery(ns_o_query, hostname, ns_c_in, type,
 984                                         NULL, 0, NULL, buf, sizeof(buf));
 985
 986         query->msgid = buf[0] << 8 | buf[1];
 987
 988         debug(lookup->resolv, "sending %d bytes", len);
 989
 990         query->nr_ns = send_query(lookup->resolv, buf, len);
 991         if (query->nr_ns <= 0) {
 992                 g_free(query);
 993                 return -EIO;
 994         }
 995
 996         query->resolv = lookup->resolv;
 997         query->lookup = lookup;
 998
 999         g_queue_push_tail(lookup->resolv->query_queue, query);
1000
1001         debug(lookup->resolv, "lookup %p id %d query %p", lookup, lookup->id,
1002                                                                         query);
1003
1004         query->timeout = g_timeout_add_seconds(5, query_timeout, query);
1005
1006         if (type == ns_t_aaaa)
1007                 lookup->ipv6_query = query;
1008         else
1009                 lookup->ipv4_query = query;
1010
1011         return 0;
1012 }
1013
1014 guint g_resolv_lookup_hostname(GResolv *resolv, const char *hostname,
1015                                 GResolvResultFunc func, gpointer user_data)
1016 {
1017         struct resolv_lookup *lookup;
1018
1019         if (!resolv)
1020                 return 0;
1021
1022         debug(resolv, "hostname %s", hostname);
1023
1024         if (!resolv->nameserver_list) {
1025                 int i;
1026
1027                 for (i = 0; i < resolv->res.nscount; i++) {
1028                         char buf[100];
1029                         int family = resolv->res.nsaddr_list[i].sin_family;
1030                         void *sa_addr = &resolv->res.nsaddr_list[i].sin_addr;
1031
1032                         if (family != AF_INET &&
1033                                         resolv->res._u._ext.nsaddrs[i]) {
1034                                 family = AF_INET6;
1035                                 sa_addr = &resolv->res._u._ext.nsaddrs[i]->sin6_addr;
1036                         }
1037
1038                         if (family != AF_INET && family != AF_INET6)
1039                                 continue;
1040
1041                         if (inet_ntop(family, sa_addr, buf, sizeof(buf)))
1042                                 g_resolv_add_nameserver(resolv, buf, 53, 0);
1043                 }
1044
1045                 if (!resolv->nameserver_list)
1046                         g_resolv_add_nameserver(resolv, "127.0.0.1", 53, 0);
1047         }
1048
1049         lookup = g_try_new0(struct resolv_lookup, 1);
1050         if (!lookup)
1051                 return 0;
1052
1053         lookup->resolv = resolv;
1054         lookup->result_func = func;
1055         lookup->result_data = user_data;
1056         lookup->id = resolv->next_lookup_id++;
1057
1058         debug(resolv, "");
1059
1060         if (resolv->result_family != AF_INET6) {
1061                 if (add_query(lookup, hostname, ns_t_a)) {
1062                         g_free(lookup);
1063                         return -EIO;
1064                 }
1065         }
1066
1067         debug(resolv, "");
1068
1069         if (resolv->result_family != AF_INET) {
1070                 if (add_query(lookup, hostname, ns_t_aaaa)) {
1071                         if (resolv->result_family != AF_INET6) {
1072                                 g_queue_remove(resolv->query_queue,
1073                                                 lookup->ipv4_query);
1074                                 destroy_query(lookup->ipv4_query);
1075                         }
1076
1077                         g_free(lookup);
1078                         return -EIO;
1079                 }
1080         }
1081
1082         debug(resolv, "");
1083
1084         g_queue_push_tail(resolv->lookup_queue, lookup);
1085
1086         debug(resolv, "lookup %p id %d", lookup, lookup->id);
1087
1088         return lookup->id;
1089 }
1090
1091 bool g_resolv_cancel_lookup(GResolv *resolv, guint id)
1092 {
1093         struct resolv_lookup *lookup;
1094         GList *list;
1095
1096         debug(resolv, "lookup id %d", id);
1097
1098         list = g_queue_find_custom(resolv->lookup_queue,
1099                                 GUINT_TO_POINTER(id), compare_lookup_id);
1100
1101         if (!list)
1102                 return false;
1103
1104         lookup = list->data;
1105
1106         debug(resolv, "lookup %p", lookup);
1107
1108         g_queue_remove(resolv->lookup_queue, lookup);
1109         destroy_lookup(lookup);
1110
1111         return true;
1112 }
1113
1114 bool g_resolv_set_address_family(GResolv *resolv, int family)
1115 {
1116         if (!resolv)
1117                 return false;
1118
1119         if (family != AF_UNSPEC && family != AF_INET && family != AF_INET6)
1120                 return false;
1121
1122         resolv->result_family = family;
1123
1124         return true;
1125 }