gweb/gresolv.c

   1 /*
   2  *
   3  *  Resolver library with GLib integration
   4  *
   5  *  Copyright (C) 2009-2012  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         gboolean 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         guint timeout;
  83
  84         uint16_t msgid;
  85
  86         struct resolv_lookup *lookup;
  87 };
  88
  89 struct resolv_nameserver {
  90         GResolv *resolv;
  91
  92         char *address;
  93         uint16_t port;
  94         unsigned long flags;
  95
  96         GIOChannel *udp_channel;
  97         guint udp_watch;
  98 };
  99
 100 struct _GResolv {
 101         int ref_count;
 102
 103         int result_family;
 104
 105         guint next_lookup_id;
 106         GQueue *lookup_queue;
 107         GQueue *query_queue;
 108
 109         int index;
 110         GList *nameserver_list;
 111
 112         struct __res_state res;
 113
 114         GResolvDebugFunc debug_func;
 115         gpointer debug_data;
 116 };
 117
 118 #define debug(resolv, format, arg...)                           \
 119         _debug(resolv, __FILE__, __func__, format, ## arg)
 120
 121 static void _debug(GResolv *resolv, const char *file, const char *caller,
 122                                                 const char *format, ...)
 123 {
 124         char str[256];
 125         va_list ap;
 126         int len;
 127
 128         if (resolv->debug_func == NULL)
 129                 return;
 130
 131         va_start(ap, format);
 132
 133         if ((len = snprintf(str, sizeof(str), "%s:%s() resolv %p ",
 134                                                 file, caller, resolv)) > 0) {
 135                 if (vsnprintf(str + len, sizeof(str) - len, format, ap) > 0)
 136                         resolv->debug_func(str, resolv->debug_data);
 137         }
 138
 139         va_end(ap);
 140 }
 141
 142 static void destroy_query(struct resolv_query *query)
 143 {
 144         debug(query->resolv, "query %p timeout %d", query, query->timeout);
 145
 146         if (query->timeout > 0)
 147                 g_source_remove(query->timeout);
 148
 149         g_free(query);
 150 }
 151
 152 static void destroy_lookup(struct resolv_lookup *lookup)
 153 {
 154         debug(lookup->resolv, "lookup %p id %d ipv4 %p ipv6 %p",
 155                 lookup, lookup->id, lookup->ipv4_query, lookup->ipv6_query);
 156
 157         if (lookup->ipv4_query != NULL) {
 158                 g_queue_remove(lookup->resolv->query_queue,
 159                                                 lookup->ipv4_query);
 160                 destroy_query(lookup->ipv4_query);
 161         }
 162
 163         if (lookup->ipv6_query != NULL) {
 164                 g_queue_remove(lookup->resolv->query_queue,
 165                                                 lookup->ipv6_query);
 166                 destroy_query(lookup->ipv6_query);
 167         }
 168
 169         g_free(lookup->results);
 170         g_free(lookup);
 171 }
 172
 173 static void find_srcaddr(struct sort_result *res)
 174 {
 175         socklen_t sl = sizeof(res->src);
 176         int fd;
 177
 178         fd = socket(res->dst.sa.sa_family, SOCK_DGRAM | SOCK_CLOEXEC,
 179                         IPPROTO_IP);
 180         if (fd < 0)
 181                 return;
 182
 183         if (connect(fd, &res->dst.sa, sizeof(res->dst)) < 0) {
 184                 close(fd);
 185                 return;
 186         }
 187
 188         if (getsockname(fd, &res->src.sa, &sl) < 0) {
 189                 close(fd);
 190                 return;
 191         }
 192
 193         res->reachable = TRUE;
 194         close(fd);
 195 }
 196
 197 struct gai_table
 198 {
 199         unsigned char addr[NS_IN6ADDRSZ];
 200         int mask;
 201         int value;
 202 };
 203
 204 static const struct gai_table gai_labels[] = {
 205         {
 206                 .addr = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 207                           0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01 },
 208                 .mask = 128,
 209                 .value = 0,
 210         }, {
 211                 .addr = { 0x20, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 212                           0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
 213                 .mask = 16,
 214                 .value = 2,
 215         }, {
 216                 .addr = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 217                           0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
 218                 .mask = 96,
 219                 .value = 3,
 220         }, {
 221                 .addr = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 222                           0x00, 0x00, 0xff, 0xff, 0x00, 0x00, 0x00, 0x00 },
 223                 .mask = 96,
 224                 .value = 4,
 225         }, {
 226                 /* Variations from RFC 3484, matching glibc behaviour */
 227                 .addr = { 0xfe, 0xc0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 228                           0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
 229                 .mask = 10,
 230                 .value = 5,
 231         }, {
 232                 .addr = { 0xfc, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 233                           0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
 234                 .mask = 7,
 235                 .value = 6,
 236         }, {
 237                 .addr = { 0x20, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 238                           0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
 239                 .mask = 32,
 240                 .value = 7,
 241         }, {
 242                 /* catch-all */
 243                 .addr = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 244                           0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
 245                 .mask = 0,
 246                 .value = 1,
 247         }
 248 };
 249
 250 static const struct gai_table gai_precedences[] = {
 251         {
 252                 .addr = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 253                           0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01 },
 254                 .mask = 128,
 255                 .value = 50,
 256         }, {
 257                 .addr = { 0x20, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 258                           0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
 259                 .mask = 16,
 260                 .value = 30,
 261         }, {
 262                 .addr = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 263                           0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
 264                 .mask = 96,
 265                 .value = 20,
 266         }, {
 267                 .addr = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 268                           0x00, 0x00, 0xff, 0xff, 0x00, 0x00, 0x00, 0x00 },
 269                 .mask = 96,
 270                 .value = 10,
 271         }, {
 272                 .addr = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 273                           0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
 274                 .mask = 0,
 275                 .value = 40,
 276         }
 277 };
 278
 279 static unsigned char v4mapped[] = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 280                                     0x00, 0x00, 0xff, 0xff, 0x00, 0x00, 0x00, 0x00 };
 281
 282 static gboolean mask_compare(const unsigned char *one,
 283                                         const unsigned char *two, int mask)
 284 {
 285         if (mask > 8) {
 286                 if (memcmp(one, two, mask / 8))
 287                         return FALSE;
 288                 one += mask / 8;
 289                 two += mask / 8;
 290                 mask %= 8;
 291         }
 292
 293         if (mask && ((*one ^ *two) >> (8 - mask)))
 294                 return FALSE;
 295
 296         return TRUE;
 297 }
 298
 299 static int match_gai_table(struct sockaddr *sa, const struct gai_table *tbl)
 300 {
 301         struct sockaddr_in *sin = (void *)sa;
 302         struct sockaddr_in6 *sin6 = (void *)sa;
 303         void *addr;
 304
 305         if (sa->sa_family == AF_INET) {
 306                 addr = v4mapped;
 307                 memcpy(v4mapped+12, &sin->sin_addr, NS_INADDRSZ);
 308         } else
 309                 addr = &sin6->sin6_addr;
 310
 311         while (1) {
 312                 if (mask_compare(addr, tbl->addr, tbl->mask))
 313                         return tbl->value;
 314                 tbl++;
 315         }
 316 }
 317
 318 #define DQUAD(_a,_b,_c,_d) ( ((_a)<<24) | ((_b)<<16) | ((_c)<<8) | (_d) )
 319 #define V4MATCH(addr, a,b,c,d, m) ( ((addr) ^ DQUAD(a,b,c,d)) >> (32 - (m)) )
 320
 321 #define RFC3484_SCOPE_LINK      2
 322 #define RFC3484_SCOPE_SITE      5
 323 #define RFC3484_SCOPE_GLOBAL    14
 324
 325 static int addr_scope(struct sockaddr *sa)
 326 {
 327         if (sa->sa_family == AF_INET) {
 328                 struct sockaddr_in *sin = (void *)sa;
 329                 guint32 addr = ntohl(sin->sin_addr.s_addr);
 330
 331                 if (V4MATCH(addr, 169,254,0,0, 16) ||
 332                                         V4MATCH(addr, 127,0,0,0, 8))
 333                         return RFC3484_SCOPE_LINK;
 334
 335                 /* Site-local */
 336                 if (V4MATCH(addr, 10,0,0,0, 8) ||
 337                                 V4MATCH(addr, 172,16,0,0, 12) ||
 338                                 V4MATCH(addr, 192,168,0,0, 16))
 339                         return RFC3484_SCOPE_SITE;
 340
 341                 /* Global */
 342                 return RFC3484_SCOPE_GLOBAL;
 343         } else {
 344                 struct sockaddr_in6 *sin6 = (void *)sa;
 345
 346                 /* Multicast addresses have a 4-bit scope field */
 347                 if (IN6_IS_ADDR_MULTICAST(&sin6->sin6_addr))
 348                         return sin6->sin6_addr.s6_addr[1] & 0xf;
 349
 350                 if (IN6_IS_ADDR_LINKLOCAL(&sin6->sin6_addr) ||
 351                                 IN6_IS_ADDR_LOOPBACK(&sin6->sin6_addr))
 352                         return RFC3484_SCOPE_LINK;
 353
 354                 if (IN6_IS_ADDR_SITELOCAL(&sin6->sin6_addr))
 355                         return RFC3484_SCOPE_SITE;
 356
 357                 return RFC3484_SCOPE_GLOBAL;
 358         }
 359 }
 360
 361 static int rfc3484_compare(const void *__one, const void *__two)
 362 {
 363         const struct sort_result *one = __one;
 364         const struct sort_result *two = __two;
 365
 366         /* Rule 1: Avoid unusable destinations */
 367         if (one->reachable && !two->reachable)
 368                 return -1;
 369         else if (two->reachable && !one->reachable)
 370                 return 1;
 371
 372         /* Rule 2: Prefer matching scope */
 373         if (one->dst_scope == one->src_scope &&
 374                                 two->dst_scope != two->src_scope)
 375                 return -1;
 376         else if (two->dst_scope == two->src_scope &&
 377                                 one->dst_scope != one->src_scope)
 378                 return 1;
 379
 380         /* Rule 3: Avoid deprecated addresses */
 381
 382         /* Rule 4: Prefer home addresses */
 383
 384         /* Rule 5: Prefer matching label */
 385         if (one->dst_label == one->src_label &&
 386                                 two->dst_label != two->src_label)
 387                 return -1;
 388         else if (two->dst_label == two->src_label &&
 389                                 one->dst_label != one->src_label)
 390                 return 1;
 391
 392         /* Rule 6: Prefer higher precedence */
 393         if (one->precedence > two->precedence)
 394                 return -1;
 395         else if (two->precedence > one->precedence)
 396                 return 1;
 397
 398         /* Rule 7: Prefer native transport */
 399
 400         /* Rule 8: Prefer smaller scope */
 401         if (one->dst_scope != two->dst_scope)
 402                 return one->dst_scope - two->dst_scope;
 403
 404         /* Rule 9: Use longest matching prefix */
 405         if (one->dst.sa.sa_family == AF_INET) {
 406                 /*
 407                  * Rule 9 is meaningless and counterproductive for Legacy IP
 408                  * unless perhaps we can tell that it's actually on the local
 409                  * subnet. But we don't (yet) have local interface config
 410                  * information, so do nothing here for Legacy IP for now.
 411                  */
 412         } else {
 413                 int i;
 414
 415                 for (i = 0; i < 4; i++) {
 416                         guint32 cmp_one, cmp_two;
 417
 418                         cmp_one = one->src.sin6.sin6_addr.s6_addr32[i] ^
 419                                         one->dst.sin6.sin6_addr.s6_addr32[i];
 420                         cmp_two = two->src.sin6.sin6_addr.s6_addr32[i] ^
 421                                         two->dst.sin6.sin6_addr.s6_addr32[i];
 422
 423                         if (!cmp_two && !cmp_one)
 424                                 continue;
 425
 426                         if (cmp_one && !cmp_two)
 427                                 return 1;
 428                         if (cmp_two && !cmp_one)
 429                                 return -1;
 430
 431                         /* g_bit_storage() is effectively fls() */
 432                         cmp_one = g_bit_storage(ntohl(cmp_one));
 433                         cmp_two = g_bit_storage(ntohl(cmp_two));
 434
 435                         if (cmp_one == cmp_two)
 436                                 break;
 437
 438                         return cmp_one - cmp_two;
 439                 }
 440         }
 441
 442
 443         /* Rule 10: Otherwise, leave the order unchanged */
 444         if (one < two)
 445                 return -1;
 446         else
 447                 return 1;
 448 }
 449
 450 static void rfc3484_sort_results(struct resolv_lookup *lookup)
 451 {
 452         int i;
 453
 454         for (i = 0; i < lookup->nr_results; i++) {
 455                 struct sort_result *res = &lookup->results[i];
 456                 find_srcaddr(res);
 457                 res->precedence = match_gai_table(&res->dst.sa,
 458                                                         gai_precedences);
 459                 res->dst_label = match_gai_table(&res->dst.sa, gai_labels);
 460                 res->src_label = match_gai_table(&res->src.sa, gai_labels);
 461                 res->dst_scope = addr_scope(&res->dst.sa);
 462                 res->src_scope = addr_scope(&res->src.sa);
 463         }
 464
 465         qsort(lookup->results, lookup->nr_results,
 466                         sizeof(struct sort_result), rfc3484_compare);
 467 }
 468
 469 static void sort_and_return_results(struct resolv_lookup *lookup)
 470 {
 471         char buf[INET6_ADDRSTRLEN + 1];
 472         GResolvResultStatus status;
 473         char **results = g_try_new0(char *, lookup->nr_results + 1);
 474         GResolvResultFunc result_func = lookup->result_func;
 475         void *result_data = lookup->result_data;
 476         int i, n = 0;
 477
 478         if (!results)
 479                 return;
 480
 481         memset(buf, 0, INET6_ADDRSTRLEN + 1);
 482
 483         rfc3484_sort_results(lookup);
 484
 485         for (i = 0; i < lookup->nr_results; i++) {
 486                 if (lookup->results[i].dst.sa.sa_family == AF_INET) {
 487                         if (inet_ntop(AF_INET,
 488                                         &lookup->results[i].dst.sin.sin_addr,
 489                                         buf, sizeof(buf) - 1) == NULL)
 490                                 continue;
 491                 } else if (lookup->results[i].dst.sa.sa_family == AF_INET6) {
 492                         if (inet_ntop(AF_INET6,
 493                                         &lookup->results[i].dst.sin6.sin6_addr,
 494                                         buf, sizeof(buf) - 1) == NULL)
 495                                 continue;
 496                 } else
 497                         continue;
 498
 499                 results[n++] = g_strdup(buf);
 500         }
 501
 502         results[n++] = NULL;
 503
 504         if (lookup->resolv->result_family == AF_INET)
 505                 status = lookup->ipv4_status;
 506         else if (lookup->resolv->result_family == AF_INET6)
 507                 status = lookup->ipv6_status;
 508         else {
 509                 if (lookup->ipv6_status == G_RESOLV_RESULT_STATUS_SUCCESS)
 510                         status = lookup->ipv6_status;
 511                 else
 512                         status = lookup->ipv4_status;
 513         }
 514
 515         debug(lookup->resolv, "lookup %p received %d results", lookup, n);
 516
 517         g_queue_remove(lookup->resolv->lookup_queue, lookup);
 518         destroy_lookup(lookup);
 519
 520         result_func(status, results, result_data);
 521
 522         g_strfreev(results);
 523 }
 524
 525 static gboolean query_timeout(gpointer user_data)
 526 {
 527         struct resolv_query *query = user_data;
 528         struct resolv_lookup *lookup = query->lookup;
 529         GResolv *resolv = query->resolv;
 530
 531         query->timeout = 0;
 532
 533         if (query == lookup->ipv4_query) {
 534                 lookup->ipv4_status = G_RESOLV_RESULT_STATUS_NO_RESPONSE;
 535                 lookup->ipv4_query = NULL;
 536         } else if (query == lookup->ipv6_query) {
 537                 lookup->ipv6_status = G_RESOLV_RESULT_STATUS_NO_RESPONSE;
 538                 lookup->ipv6_query = NULL;
 539         }
 540
 541         g_queue_remove(resolv->query_queue, query);
 542
 543         if (lookup->ipv4_query == NULL && lookup->ipv6_query == NULL)
 544                 sort_and_return_results(lookup);
 545
 546         destroy_query(query);
 547
 548         return FALSE;
 549 }
 550
 551 static void free_nameserver(struct resolv_nameserver *nameserver)
 552 {
 553         if (nameserver == NULL)
 554                 return;
 555
 556         if (nameserver->udp_watch > 0)
 557                 g_source_remove(nameserver->udp_watch);
 558
 559         if (nameserver->udp_channel != NULL) {
 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
 584         if (resolv->nameserver_list == NULL)
 585                 return -ENOENT;
 586
 587         for (list = g_list_first(resolv->nameserver_list);
 588                                         list; list = g_list_next(list)) {
 589                 struct resolv_nameserver *nameserver = list->data;
 590                 int sk, sent;
 591
 592                 if (nameserver->udp_channel == NULL)
 593                         continue;
 594
 595                 sk = g_io_channel_unix_get_fd(nameserver->udp_channel);
 596
 597                 sent = send(sk, buf, len, 0);
 598                 if (sent < 0)
 599                         continue;
 600         }
 601
 602         return 0;
 603 }
 604
 605 static gint compare_lookup_id(gconstpointer a, gconstpointer b)
 606 {
 607         const struct resolv_lookup *lookup = a;
 608         guint id = GPOINTER_TO_UINT(b);
 609
 610         if (lookup->id < id)
 611                 return -1;
 612
 613         if (lookup->id > id)
 614                 return 1;
 615
 616         return 0;
 617 }
 618
 619 static gint compare_query_msgid(gconstpointer a, gconstpointer b)
 620 {
 621         const struct resolv_query *query = a;
 622         uint16_t msgid = GPOINTER_TO_UINT(b);
 623
 624         if (query->msgid < msgid)
 625                 return -1;
 626
 627         if (query->msgid > msgid)
 628                 return 1;
 629
 630         return 0;
 631 }
 632
 633 static void add_result(struct resolv_lookup *lookup, int family,
 634                                                         const void *data)
 635 {
 636         int n = lookup->nr_results++;
 637         lookup->results = g_try_realloc(lookup->results,
 638                                         sizeof(struct sort_result) * (n + 1));
 639         if (lookup->results == NULL)
 640                 return;
 641
 642         memset(&lookup->results[n], 0, sizeof(struct sort_result));
 643
 644         lookup->results[n].dst.sa.sa_family = family;
 645         if (family == AF_INET)
 646                 memcpy(&lookup->results[n].dst.sin.sin_addr,
 647                                                 data, NS_INADDRSZ);
 648         else
 649                 memcpy(&lookup->results[n].dst.sin6.sin6_addr,
 650                                                 data, NS_IN6ADDRSZ);
 651 }
 652
 653 static void parse_response(struct resolv_nameserver *nameserver,
 654                                         const unsigned char *buf, int len)
 655 {
 656         GResolv *resolv = nameserver->resolv;
 657         GResolvResultStatus status;
 658         struct resolv_query *query;
 659         struct resolv_lookup *lookup;
 660         GList *list;
 661         ns_msg msg;
 662         ns_rr rr;
 663         int i, rcode, count;
 664
 665         debug(resolv, "response from %s", nameserver->address);
 666
 667         ns_initparse(buf, len, &msg);
 668
 669         rcode = ns_msg_getflag(msg, ns_f_rcode);
 670         count = ns_msg_count(msg, ns_s_an);
 671
 672         debug(resolv, "msg id: 0x%04x rcode: %d count: %d",
 673                                         ns_msg_id(msg), rcode, count);
 674
 675         switch (rcode) {
 676         case ns_r_noerror:
 677                 status = G_RESOLV_RESULT_STATUS_SUCCESS;
 678                 break;
 679         case ns_r_formerr:
 680                 status = G_RESOLV_RESULT_STATUS_FORMAT_ERROR;
 681                 break;
 682         case ns_r_servfail:
 683                 status = G_RESOLV_RESULT_STATUS_SERVER_FAILURE;
 684                 break;
 685         case ns_r_nxdomain:
 686                 status = G_RESOLV_RESULT_STATUS_NAME_ERROR;
 687                 break;
 688         case ns_r_notimpl:
 689                 status = G_RESOLV_RESULT_STATUS_NOT_IMPLEMENTED;
 690                 break;
 691         case ns_r_refused:
 692                 status = G_RESOLV_RESULT_STATUS_REFUSED;
 693                 break;
 694         default:
 695                 status = G_RESOLV_RESULT_STATUS_ERROR;
 696                 break;
 697         }
 698
 699         list = g_queue_find_custom(resolv->query_queue,
 700                         GUINT_TO_POINTER(ns_msg_id(msg)), compare_query_msgid);
 701         if (!list)
 702                 return;
 703
 704         query = list->data;
 705         lookup = query->lookup;
 706
 707         if (query == lookup->ipv6_query) {
 708                 lookup->ipv6_status = status;
 709                 lookup->ipv6_query = NULL;
 710         } else if (query == lookup->ipv4_query) {
 711                 lookup->ipv4_status = status;
 712                 lookup->ipv4_query = NULL;
 713         }
 714
 715         for (i = 0; i < count; i++) {
 716                 ns_parserr(&msg, ns_s_an, i, &rr);
 717
 718                 if (ns_rr_class(rr) != ns_c_in)
 719                         continue;
 720
 721                 g_assert(offsetof(struct sockaddr_in, sin_addr) ==
 722                                 offsetof(struct sockaddr_in6, sin6_flowinfo));
 723
 724                 if (ns_rr_type(rr) == ns_t_a &&
 725                                         ns_rr_rdlen(rr) == NS_INADDRSZ) {
 726                         add_result(lookup, AF_INET, ns_rr_rdata(rr));
 727                 } else if (ns_rr_type(rr) == ns_t_aaaa &&
 728                                         ns_rr_rdlen(rr) == NS_IN6ADDRSZ) {
 729                         add_result(lookup, AF_INET6, ns_rr_rdata(rr));
 730                 }
 731         }
 732
 733         g_queue_remove(resolv->query_queue, query);
 734
 735         if (lookup->ipv4_query == NULL && lookup->ipv6_query == NULL)
 736                 sort_and_return_results(lookup);
 737
 738         destroy_query(query);
 739 }
 740
 741 static gboolean received_udp_data(GIOChannel *channel, GIOCondition cond,
 742                                                         gpointer user_data)
 743 {
 744         struct resolv_nameserver *nameserver = user_data;
 745         unsigned char buf[4096];
 746         int sk, len;
 747
 748         if (cond & (G_IO_NVAL | G_IO_ERR | G_IO_HUP)) {
 749                 nameserver->udp_watch = 0;
 750                 return FALSE;
 751         }
 752
 753         sk = g_io_channel_unix_get_fd(nameserver->udp_channel);
 754
 755         len = recv(sk, buf, sizeof(buf), 0);
 756         if (len < 12)
 757                 return TRUE;
 758
 759         parse_response(nameserver, buf, len);
 760
 761         return TRUE;
 762 }
 763
 764 static int connect_udp_channel(struct resolv_nameserver *nameserver)
 765 {
 766         struct addrinfo hints, *rp;
 767         char portnr[6];
 768         int err, sk;
 769
 770         memset(&hints, 0, sizeof(hints));
 771         hints.ai_family = AF_UNSPEC;
 772         hints.ai_socktype = SOCK_DGRAM;
 773         hints.ai_flags = AI_PASSIVE | AI_NUMERICSERV | AI_NUMERICHOST;
 774
 775         sprintf(portnr, "%d", nameserver->port);
 776         err = getaddrinfo(nameserver->address, portnr, &hints, &rp);
 777         if (err)
 778                 return -EINVAL;
 779
 780         /*
 781          * Do not blindly copy this code elsewhere; it doesn't loop over the
 782          * results using ->ai_next as it should. That's OK in *this* case
 783          * because it was a numeric lookup; we *know* there's only one.
 784          */
 785         if (!rp)
 786                 return -EINVAL;
 787
 788         sk = socket(rp->ai_family, rp->ai_socktype, rp->ai_protocol);
 789         if (sk < 0) {
 790                 freeaddrinfo(rp);
 791                 return -EIO;
 792         }
 793
 794         /*
 795          * If nameserver points to localhost ip, their is no need to
 796          * bind the socket on any interface.
 797          */
 798         if (nameserver->resolv->index > 0 &&
 799                         strncmp(nameserver->address, "127.0.0.1", 9) != 0) {
 800                 char interface[IF_NAMESIZE];
 801
 802                 memset(interface, 0, IF_NAMESIZE);
 803                 if (if_indextoname(nameserver->resolv->index,
 804                                                 interface) != NULL) {
 805                         if (setsockopt(sk, SOL_SOCKET, SO_BINDTODEVICE,
 806                                                 interface, IF_NAMESIZE) < 0) {
 807                                 close(sk);
 808                                 freeaddrinfo(rp);
 809                                 return -EIO;
 810                         }
 811                 }
 812         }
 813
 814         if (connect(sk, rp->ai_addr, rp->ai_addrlen) < 0) {
 815                 close(sk);
 816                 freeaddrinfo(rp);
 817                 return -EIO;
 818         }
 819
 820         freeaddrinfo(rp);
 821
 822         nameserver->udp_channel = g_io_channel_unix_new(sk);
 823         if (nameserver->udp_channel == NULL) {
 824                 close(sk);
 825                 return -ENOMEM;
 826         }
 827
 828         g_io_channel_set_close_on_unref(nameserver->udp_channel, TRUE);
 829
 830         nameserver->udp_watch = g_io_add_watch(nameserver->udp_channel,
 831                                 G_IO_IN | G_IO_NVAL | G_IO_ERR | G_IO_HUP,
 832                                 received_udp_data, nameserver);
 833
 834         return 0;
 835 }
 836
 837 GResolv *g_resolv_new(int index)
 838 {
 839         GResolv *resolv;
 840
 841         if (index < 0)
 842                 return NULL;
 843
 844         resolv = g_try_new0(GResolv, 1);
 845         if (resolv == NULL)
 846                 return NULL;
 847
 848         resolv->ref_count = 1;
 849
 850         resolv->result_family = AF_UNSPEC;
 851
 852         resolv->next_lookup_id = 1;
 853
 854         resolv->query_queue = g_queue_new();
 855         if (resolv->query_queue == NULL) {
 856                 g_free(resolv);
 857                 return NULL;
 858         }
 859
 860         resolv->lookup_queue = g_queue_new();
 861         if (resolv->lookup_queue == NULL) {
 862                 g_queue_free(resolv->query_queue);
 863                 g_free(resolv);
 864                 return NULL;
 865         }
 866
 867         resolv->index = index;
 868         resolv->nameserver_list = NULL;
 869
 870         res_ninit(&resolv->res);
 871
 872         return resolv;
 873 }
 874
 875 GResolv *g_resolv_ref(GResolv *resolv)
 876 {
 877         if (resolv == NULL)
 878                 return NULL;
 879
 880         __sync_fetch_and_add(&resolv->ref_count, 1);
 881
 882         return resolv;
 883 }
 884
 885 void g_resolv_unref(GResolv *resolv)
 886 {
 887         struct resolv_query *query;
 888         struct resolv_lookup *lookup;
 889
 890         if (resolv == NULL)
 891                 return;
 892
 893         if (__sync_fetch_and_sub(&resolv->ref_count, 1) != 1)
 894                 return;
 895
 896         while ((lookup = g_queue_pop_head(resolv->lookup_queue))) {
 897                 debug(resolv, "lookup %p id %d", lookup, lookup->id);
 898                 destroy_lookup(lookup);
 899         }
 900
 901         while ((query = g_queue_pop_head(resolv->query_queue))) {
 902                 debug(resolv, "query %p", query);
 903                 destroy_query(query);
 904         }
 905
 906         g_queue_free(resolv->query_queue);
 907         g_queue_free(resolv->lookup_queue);
 908
 909         flush_nameservers(resolv);
 910
 911         res_nclose(&resolv->res);
 912
 913         g_free(resolv);
 914 }
 915
 916 void g_resolv_set_debug(GResolv *resolv, GResolvDebugFunc func,
 917                                                 gpointer user_data)
 918 {
 919         if (resolv == NULL)
 920                 return;
 921
 922         resolv->debug_func = func;
 923         resolv->debug_data = user_data;
 924 }
 925
 926 gboolean g_resolv_add_nameserver(GResolv *resolv, const char *address,
 927                                         uint16_t port, unsigned long flags)
 928 {
 929         struct resolv_nameserver *nameserver;
 930
 931         if (resolv == NULL)
 932                 return FALSE;
 933
 934         nameserver = g_try_new0(struct resolv_nameserver, 1);
 935         if (nameserver == NULL)
 936                 return FALSE;
 937
 938         nameserver->address = g_strdup(address);
 939         nameserver->port = port;
 940         nameserver->flags = flags;
 941         nameserver->resolv = resolv;
 942
 943         if (connect_udp_channel(nameserver) < 0) {
 944                 free_nameserver(nameserver);
 945                 return FALSE;
 946         }
 947
 948         resolv->nameserver_list = g_list_append(resolv->nameserver_list,
 949                                                                 nameserver);
 950
 951         debug(resolv, "setting nameserver %s", address);
 952
 953         return TRUE;
 954 }
 955
 956 void g_resolv_flush_nameservers(GResolv *resolv)
 957 {
 958         if (resolv == NULL)
 959                 return;
 960
 961         flush_nameservers(resolv);
 962 }
 963
 964 static gint add_query(struct resolv_lookup *lookup, const char *hostname, int type)
 965 {
 966         struct resolv_query *query = g_try_new0(struct resolv_query, 1);
 967         unsigned char buf[4096];
 968         int len;
 969
 970         if (query == NULL)
 971                 return -ENOMEM;
 972
 973         len = res_mkquery(ns_o_query, hostname, ns_c_in, type,
 974                                         NULL, 0, NULL, buf, sizeof(buf));
 975
 976         query->msgid = buf[0] << 8 | buf[1];
 977
 978         debug(lookup->resolv, "sending %d bytes", len);
 979
 980         if (send_query(lookup->resolv, buf, len) < 0) {
 981                 g_free(query);
 982                 return -EIO;
 983         }
 984
 985         query->resolv = lookup->resolv;
 986         query->lookup = lookup;
 987
 988         g_queue_push_tail(lookup->resolv->query_queue, query);
 989
 990         debug(lookup->resolv, "lookup %p id %d query %p", lookup, lookup->id,
 991                                                                         query);
 992
 993         query->timeout = g_timeout_add_seconds(5, query_timeout, query);
 994
 995         if (type == ns_t_aaaa)
 996                 lookup->ipv6_query = query;
 997         else
 998                 lookup->ipv4_query = query;
 999
1000         return 0;
1001 }
1002
1003 guint g_resolv_lookup_hostname(GResolv *resolv, const char *hostname,
1004                                 GResolvResultFunc func, gpointer user_data)
1005 {
1006         struct resolv_lookup *lookup;
1007
1008         if (resolv == NULL)
1009                 return 0;
1010
1011         debug(resolv, "hostname %s", hostname);
1012
1013         if (resolv->nameserver_list == NULL) {
1014                 int i;
1015
1016                 for (i = 0; i < resolv->res.nscount; i++) {
1017                         char buf[100];
1018                         int family = resolv->res.nsaddr_list[i].sin_family;
1019                         void *sa_addr = &resolv->res.nsaddr_list[i].sin_addr;
1020
1021                         if (family != AF_INET &&
1022                                         resolv->res._u._ext.nsaddrs[i]) {
1023                                 family = AF_INET6;
1024                                 sa_addr = &resolv->res._u._ext.nsaddrs[i]->sin6_addr;
1025                         }
1026
1027                         if (family != AF_INET && family != AF_INET6)
1028                                 continue;
1029
1030                         if (inet_ntop(family, sa_addr, buf, sizeof(buf)))
1031                                 g_resolv_add_nameserver(resolv, buf, 53, 0);
1032                 }
1033
1034                 if (resolv->nameserver_list == NULL)
1035                         g_resolv_add_nameserver(resolv, "127.0.0.1", 53, 0);
1036         }
1037
1038         lookup = g_try_new0(struct resolv_lookup, 1);
1039         if (lookup == NULL)
1040                 return 0;
1041
1042         lookup->resolv = resolv;
1043         lookup->result_func = func;
1044         lookup->result_data = user_data;
1045         lookup->id = resolv->next_lookup_id++;
1046
1047         if (resolv->result_family != AF_INET6) {
1048                 if (add_query(lookup, hostname, ns_t_a)) {
1049                         g_free(lookup);
1050                         return -EIO;
1051                 }
1052         }
1053
1054         if (resolv->result_family != AF_INET) {
1055                 if (add_query(lookup, hostname, ns_t_aaaa)) {
1056                         if (resolv->result_family != AF_INET6) {
1057                                 g_queue_remove(resolv->query_queue,
1058                                                 lookup->ipv4_query);
1059                                 destroy_query(lookup->ipv4_query);
1060                         }
1061
1062                         g_free(lookup);
1063                         return -EIO;
1064                 }
1065         }
1066
1067         g_queue_push_tail(resolv->lookup_queue, lookup);
1068
1069         debug(resolv, "lookup %p id %d", lookup, lookup->id);
1070
1071         return lookup->id;
1072 }
1073
1074 gboolean g_resolv_cancel_lookup(GResolv *resolv, guint id)
1075 {
1076         struct resolv_lookup *lookup;
1077         GList *list;
1078
1079         debug(resolv, "lookup id %d", id);
1080
1081         list = g_queue_find_custom(resolv->lookup_queue,
1082                                 GUINT_TO_POINTER(id), compare_lookup_id);
1083
1084         if (list == NULL)
1085                 return FALSE;
1086
1087         lookup = list->data;
1088
1089         debug(resolv, "lookup %p", lookup);
1090
1091         g_queue_remove(resolv->lookup_queue, lookup);
1092         destroy_lookup(lookup);
1093
1094         return TRUE;
1095 }
1096
1097 gboolean g_resolv_set_address_family(GResolv *resolv, int family)
1098 {
1099         if (resolv == NULL)
1100                 return FALSE;
1101
1102         if (family != AF_UNSPEC && family != AF_INET && family != AF_INET6)
1103                 return FALSE;
1104
1105         resolv->result_family = family;
1106
1107         return TRUE;
1108 }