gweb/gresolv.c

   1 /*
   2  *
   3  *  Resolver library with GLib integration
   4  *
   5  *  Copyright (C) 2009-2010  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
  38 #include "gresolv.h"
  39
  40 struct sort_result {
  41         int precedence;
  42         int src_scope;
  43         int dst_scope;
  44         int src_label;
  45         int dst_label;
  46         gboolean reachable;
  47         union {
  48                 struct sockaddr sa;
  49                 struct sockaddr_in sin;
  50                 struct sockaddr_in6 sin6;
  51         } src;
  52         union {
  53                 struct sockaddr sa;
  54                 struct sockaddr_in sin;
  55                 struct sockaddr_in6 sin6;
  56         } dst;
  57 };
  58
  59 struct resolv_query;
  60
  61 struct resolv_lookup {
  62         GResolv *resolv;
  63         guint id;
  64
  65         int nr_results;
  66         struct sort_result *results;
  67
  68         struct resolv_query *ipv4_query;
  69         struct resolv_query *ipv6_query;
  70
  71         guint ipv4_status;
  72         guint ipv6_status;
  73
  74         GResolvResultFunc result_func;
  75         gpointer result_data;
  76 };
  77
  78 struct resolv_query {
  79         GResolv *resolv;
  80
  81         guint timeout;
  82
  83         uint16_t msgid;
  84
  85         struct resolv_lookup *lookup;
  86 };
  87
  88 struct resolv_nameserver {
  89         GResolv *resolv;
  90
  91         char *address;
  92         uint16_t port;
  93         unsigned long flags;
  94
  95         GIOChannel *udp_channel;
  96         guint udp_watch;
  97 };
  98
  99 struct _GResolv {
 100         gint ref_count;
 101
 102         int result_family;
 103
 104         guint next_lookup_id;
 105         GQueue *lookup_queue;
 106         GQueue *query_queue;
 107
 108         int index;
 109         GList *nameserver_list;
 110
 111         struct __res_state res;
 112
 113         GResolvDebugFunc debug_func;
 114         gpointer debug_data;
 115 };
 116
 117 static inline void debug(GResolv *resolv, const char *format, ...)
 118 {
 119         char str[256];
 120         va_list ap;
 121
 122         if (resolv->debug_func == NULL)
 123                 return;
 124
 125         va_start(ap, format);
 126
 127         if (vsnprintf(str, sizeof(str), format, ap) > 0)
 128                 resolv->debug_func(str, resolv->debug_data);
 129
 130         va_end(ap);
 131 }
 132
 133 static void destroy_query(struct resolv_query *query)
 134 {
 135         if (query->timeout > 0)
 136                 g_source_remove(query->timeout);
 137
 138         g_free(query);
 139 }
 140
 141 static void destroy_lookup(struct resolv_lookup *lookup)
 142 {
 143         if (lookup->ipv4_query != NULL) {
 144                 g_queue_remove(lookup->resolv->query_queue,
 145                                                 lookup->ipv4_query);
 146                 destroy_query(lookup->ipv4_query);
 147         }
 148
 149         if (lookup->ipv6_query != NULL) {
 150                 g_queue_remove(lookup->resolv->query_queue,
 151                                                 lookup->ipv6_query);
 152                 destroy_query(lookup->ipv6_query);
 153         }
 154
 155         g_free(lookup->results);
 156         g_free(lookup);
 157 }
 158
 159 static void find_srcaddr(struct sort_result *res)
 160 {
 161         socklen_t sl = sizeof(res->src);
 162         int fd;
 163
 164         fd = socket(res->dst.sa.sa_family, SOCK_DGRAM, IPPROTO_IP);
 165         if (fd < 0)
 166                 return;
 167
 168         if (connect(fd, &res->dst.sa, sizeof(res->dst)) < 0) {
 169                 close(fd);
 170                 return;
 171         }
 172
 173         if (getsockname(fd, &res->src.sa, &sl) < 0) {
 174                 close(fd);
 175                 return;
 176         }
 177
 178         res->reachable = TRUE;
 179         close(fd);
 180 }
 181
 182 struct gai_table
 183 {
 184         unsigned char addr[NS_IN6ADDRSZ];
 185         int mask;
 186         int value;
 187 };
 188
 189 static const struct gai_table gai_labels[] = {
 190         {
 191                 .addr = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 192                           0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01 },
 193                 .mask = 128,
 194                 .value = 0,
 195         }, {
 196                 .addr = { 0x20, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 197                           0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
 198                 .mask = 16,
 199                 .value = 2,
 200         }, {
 201                 .addr = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 202                           0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
 203                 .mask = 96,
 204                 .value = 3,
 205         }, {
 206                 .addr = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 207                           0x00, 0x00, 0xff, 0xff, 0x00, 0x00, 0x00, 0x00 },
 208                 .mask = 96,
 209                 .value = 4,
 210         }, {
 211                 /* Variations from RFC 3484, matching glibc behaviour */
 212                 .addr = { 0xfe, 0xc0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 213                           0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
 214                 .mask = 10,
 215                 .value = 5,
 216         }, {
 217                 .addr = { 0xfc, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 218                           0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
 219                 .mask = 7,
 220                 .value = 6,
 221         }, {
 222                 .addr = { 0x20, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 223                           0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
 224                 .mask = 32,
 225                 .value = 7,
 226         }, {
 227                 /* catch-all */
 228                 .addr = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 229                           0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
 230                 .mask = 0,
 231                 .value = 1,
 232         }
 233 };
 234
 235 static const struct gai_table gai_precedences[] = {
 236         {
 237                 .addr = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 238                           0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01 },
 239                 .mask = 128,
 240                 .value = 50,
 241         }, {
 242                 .addr = { 0x20, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 243                           0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
 244                 .mask = 16,
 245                 .value = 30,
 246         }, {
 247                 .addr = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 248                           0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
 249                 .mask = 96,
 250                 .value = 20,
 251         }, {
 252                 .addr = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 253                           0x00, 0x00, 0xff, 0xff, 0x00, 0x00, 0x00, 0x00 },
 254                 .mask = 96,
 255                 .value = 10,
 256         }, {
 257                 .addr = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 258                           0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
 259                 .mask = 0,
 260                 .value = 40,
 261         }
 262 };
 263
 264 static unsigned char v4mapped[] = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 265                                     0x00, 0x00, 0xff, 0xff, 0x00, 0x00, 0x00, 0x00 };
 266
 267 static gboolean mask_compare(const unsigned char *one,
 268                                         const unsigned char *two, int mask)
 269 {
 270         if (mask > 8) {
 271                 if (memcmp(one, two, mask / 8))
 272                         return FALSE;
 273                 one += mask / 8;
 274                 two += mask / 8;
 275                 mask %= 8;
 276         }
 277
 278         if (mask && ((*one ^ *two) >> (8 - mask)))
 279                 return FALSE;
 280
 281         return TRUE;
 282 }
 283
 284 static int match_gai_table(struct sockaddr *sa, const struct gai_table *tbl)
 285 {
 286         struct sockaddr_in *sin = (void *)sa;
 287         struct sockaddr_in6 *sin6 = (void *)sa;
 288         void *addr;
 289
 290         if (sa->sa_family == AF_INET) {
 291                 addr = v4mapped;
 292                 memcpy(v4mapped+12, &sin->sin_addr, NS_INADDRSZ);
 293         } else
 294                 addr = &sin6->sin6_addr;
 295
 296         while (1) {
 297                 if (mask_compare(addr, tbl->addr, tbl->mask))
 298                         return tbl->value;
 299                 tbl++;
 300         }
 301 }
 302
 303 #define DQUAD(_a,_b,_c,_d) ( ((_a)<<24) | ((_b)<<16) | ((_c)<<8) | (_d) )
 304 #define V4MATCH(addr, a,b,c,d, m) ( ((addr) ^ DQUAD(a,b,c,d)) >> (32 - (m)) )
 305
 306 #define RFC3484_SCOPE_LINK      2
 307 #define RFC3484_SCOPE_SITE      5
 308 #define RFC3484_SCOPE_GLOBAL    14
 309
 310 static int addr_scope(struct sockaddr *sa)
 311 {
 312         if (sa->sa_family == AF_INET) {
 313                 struct sockaddr_in *sin = (void *)sa;
 314                 guint32 addr = ntohl(sin->sin_addr.s_addr);
 315
 316                 if (V4MATCH(addr, 169,254,0,0, 16) ||
 317                                         V4MATCH(addr, 127,0,0,0, 8))
 318                         return RFC3484_SCOPE_LINK;
 319
 320                 /* Site-local */
 321                 if (V4MATCH(addr, 10,0,0,0, 8) ||
 322                                 V4MATCH(addr, 172,16,0,0, 12) ||
 323                                 V4MATCH(addr, 192,168,0,0, 16))
 324                         return RFC3484_SCOPE_SITE;
 325
 326                 /* Global */
 327                 return RFC3484_SCOPE_GLOBAL;
 328         } else {
 329                 struct sockaddr_in6 *sin6 = (void *)sa;
 330
 331                 /* Multicast addresses have a 4-bit scope field */
 332                 if (IN6_IS_ADDR_MULTICAST(&sin6->sin6_addr))
 333                         return sin6->sin6_addr.s6_addr[1] & 0xf;
 334
 335                 if (IN6_IS_ADDR_LINKLOCAL(&sin6->sin6_addr) ||
 336                                 IN6_IS_ADDR_LOOPBACK(&sin6->sin6_addr))
 337                         return RFC3484_SCOPE_LINK;
 338
 339                 if (IN6_IS_ADDR_SITELOCAL(&sin6->sin6_addr))
 340                         return RFC3484_SCOPE_SITE;
 341
 342                 return RFC3484_SCOPE_GLOBAL;
 343         }
 344 }
 345
 346 static int rfc3484_compare(const void *__one, const void *__two)
 347 {
 348         const struct sort_result *one = __one;
 349         const struct sort_result *two = __two;
 350
 351         /* Rule 1: Avoid unusable destinations */
 352         if (one->reachable && !two->reachable)
 353                 return -1;
 354         else if (two->reachable && !one->reachable)
 355                 return 1;
 356
 357         /* Rule 2: Prefer matching scope */
 358         if (one->dst_scope == one->src_scope &&
 359                                 two->dst_scope != two->src_scope)
 360                 return -1;
 361         else if (two->dst_scope == two->src_scope &&
 362                                 one->dst_scope != one->src_scope)
 363                 return 1;
 364
 365         /* Rule 3: Avoid deprecated addresses */
 366
 367         /* Rule 4: Prefer home addresses */
 368
 369         /* Rule 5: Prefer matching label */
 370         if (one->dst_label == one->src_label &&
 371                                 two->dst_label != two->src_label)
 372                 return -1;
 373         else if (two->dst_label == two->src_label &&
 374                                 one->dst_label != one->src_label)
 375                 return 1;
 376
 377         /* Rule 6: Prefer higher precedence */
 378         if (one->precedence > two->precedence)
 379                 return -1;
 380         else if (two->precedence > one->precedence)
 381                 return 1;
 382
 383         /* Rule 7: Prefer native transport */
 384
 385         /* Rule 8: Prefer smaller scope */
 386         if (one->dst_scope != two->dst_scope)
 387                 return one->dst_scope - two->dst_scope;
 388
 389         /* Rule 9: Use longest matching prefix */
 390         if (one->dst.sa.sa_family == AF_INET) {
 391                 /*
 392                  * Rule 9 is meaningless and counterproductive for Legacy IP
 393                  * unless perhaps we can tell that it's actually on the local
 394                  * subnet. But we don't (yet) have local interface config
 395                  * information, so do nothing here for Legacy IP for now.
 396                  */
 397         } else {
 398                 int i;
 399
 400                 for (i = 0; i < 4; i++) {
 401                         guint32 cmp_one, cmp_two;
 402
 403                         cmp_one = one->src.sin6.sin6_addr.s6_addr32[i] ^
 404                                         one->dst.sin6.sin6_addr.s6_addr32[i];
 405                         cmp_two = two->src.sin6.sin6_addr.s6_addr32[i] ^
 406                                         two->dst.sin6.sin6_addr.s6_addr32[i];
 407
 408                         if (!cmp_two && !cmp_one)
 409                                 continue;
 410
 411                         if (cmp_one && !cmp_two)
 412                                 return 1;
 413                         if (cmp_two && !cmp_one)
 414                                 return -1;
 415
 416                         /* g_bit_storage() is effectively fls() */
 417                         cmp_one = g_bit_storage(ntohl(cmp_one));
 418                         cmp_two = g_bit_storage(ntohl(cmp_two));
 419
 420                         if (cmp_one == cmp_two)
 421                                 break;
 422
 423                         return cmp_one - cmp_two;
 424                 }
 425         }
 426
 427
 428         /* Rule 10: Otherwise, leave the order unchanged */
 429         if (one < two)
 430                 return -1;
 431         else
 432                 return 1;
 433 }
 434
 435 static void rfc3484_sort_results(struct resolv_lookup *lookup)
 436 {
 437         int i;
 438
 439         for (i = 0; i < lookup->nr_results; i++) {
 440                 struct sort_result *res = &lookup->results[i];
 441                 find_srcaddr(res);
 442                 res->precedence = match_gai_table(&res->dst.sa,
 443                                                         gai_precedences);
 444                 res->dst_label = match_gai_table(&res->dst.sa, gai_labels);
 445                 res->src_label = match_gai_table(&res->src.sa, gai_labels);
 446                 res->dst_scope = addr_scope(&res->dst.sa);
 447                 res->src_scope = addr_scope(&res->src.sa);
 448         }
 449
 450         qsort(lookup->results, lookup->nr_results,
 451                         sizeof(struct sort_result), rfc3484_compare);
 452 }
 453
 454 static void sort_and_return_results(struct resolv_lookup *lookup)
 455 {
 456         char buf[100];
 457         GResolvResultStatus status;
 458         char **results = g_try_new0(char *, lookup->nr_results + 1);
 459         int i, n = 0;
 460
 461         if (!results)
 462                 return;
 463
 464         rfc3484_sort_results(lookup);
 465
 466         for (i = 0; i < lookup->nr_results; i++) {
 467                 if (lookup->results[i].dst.sa.sa_family == AF_INET) {
 468                         if (inet_ntop(AF_INET,
 469                                         &lookup->results[i].dst.sin.sin_addr,
 470                                         buf, sizeof(buf)) == NULL)
 471                                 continue;
 472                 } else if (lookup->results[i].dst.sa.sa_family == AF_INET6) {
 473                         if (inet_ntop(AF_INET6,
 474                                         &lookup->results[i].dst.sin6.sin6_addr,
 475                                         buf, sizeof(buf)) == NULL)
 476                                 continue;
 477                 } else
 478                         continue;
 479
 480                 results[n++] = strdup(buf);
 481         }
 482
 483         results[n++] = NULL;
 484
 485         status = lookup->ipv4_status;
 486
 487         if (status == G_RESOLV_RESULT_STATUS_SUCCESS)
 488                 status = lookup->ipv6_status;
 489
 490         lookup->result_func(status, results, lookup->result_data);
 491
 492         g_strfreev(results);
 493         g_queue_remove(lookup->resolv->lookup_queue, lookup);
 494         destroy_lookup(lookup);
 495 }
 496
 497 static gboolean query_timeout(gpointer user_data)
 498 {
 499         struct resolv_query *query = user_data;
 500         struct resolv_lookup *lookup = query->lookup;
 501         GResolv *resolv = query->resolv;
 502
 503         query->timeout = 0;
 504
 505         if (query == lookup->ipv4_query) {
 506                 lookup->ipv4_status = G_RESOLV_RESULT_STATUS_NO_RESPONSE;
 507                 lookup->ipv4_query = NULL;
 508         } else if (query == lookup->ipv6_query) {
 509                 lookup->ipv6_status = G_RESOLV_RESULT_STATUS_NO_RESPONSE;
 510                 lookup->ipv6_query = NULL;
 511         }
 512
 513         if (lookup->ipv4_query == NULL && lookup->ipv4_query == NULL)
 514                 sort_and_return_results(lookup);
 515
 516         destroy_query(query);
 517         g_queue_remove(resolv->query_queue, query);
 518
 519         return FALSE;
 520 }
 521
 522 static void free_nameserver(struct resolv_nameserver *nameserver)
 523 {
 524         if (nameserver == NULL)
 525                 return;
 526
 527         if (nameserver->udp_watch > 0)
 528                 g_source_remove(nameserver->udp_watch);
 529
 530         if (nameserver->udp_channel != NULL)
 531                 g_io_channel_unref(nameserver->udp_channel);
 532
 533         g_free(nameserver->address);
 534         g_free(nameserver);
 535 }
 536
 537 static void flush_nameservers(GResolv *resolv)
 538 {
 539         GList *list;
 540
 541         for (list = g_list_first(resolv->nameserver_list);
 542                                         list; list = g_list_next(list))
 543                 free_nameserver(list->data);
 544
 545         g_list_free(resolv->nameserver_list);
 546         resolv->nameserver_list = NULL;
 547 }
 548
 549 static int send_query(GResolv *resolv, const unsigned char *buf, int len)
 550 {
 551         GList *list;
 552
 553         if (resolv->nameserver_list == NULL)
 554                 return -ENOENT;
 555
 556         for (list = g_list_first(resolv->nameserver_list);
 557                                         list; list = g_list_next(list)) {
 558                 struct resolv_nameserver *nameserver = list->data;
 559                 int sk, sent;
 560
 561                 if (nameserver->udp_channel == NULL)
 562                         continue;
 563
 564                 sk = g_io_channel_unix_get_fd(nameserver->udp_channel);
 565
 566                 sent = send(sk, buf, len, 0);
 567                 if (sent < 0)
 568                         continue;
 569         }
 570
 571         return 0;
 572 }
 573
 574 static gint compare_lookup_id(gconstpointer a, gconstpointer b)
 575 {
 576         const struct resolv_lookup *lookup = a;
 577         guint id = GPOINTER_TO_UINT(b);
 578
 579         if (lookup->id < id)
 580                 return -1;
 581
 582         if (lookup->id > id)
 583                 return 1;
 584
 585         return 0;
 586 }
 587
 588 static gint compare_query_msgid(gconstpointer a, gconstpointer b)
 589 {
 590         const struct resolv_query *query = a;
 591         uint16_t msgid = GPOINTER_TO_UINT(b);
 592
 593         if (query->msgid < msgid)
 594                 return -1;
 595
 596         if (query->msgid > msgid)
 597                 return 1;
 598
 599         return 0;
 600 }
 601
 602 static void add_result(struct resolv_lookup *lookup, int family,
 603                                                         const void *data)
 604 {
 605         int n = lookup->nr_results++;
 606         lookup->results = g_realloc(lookup->results,
 607                                         sizeof(struct sort_result) * (n + 1));
 608
 609         memset(&lookup->results[n], 0, sizeof(struct sort_result));
 610
 611         lookup->results[n].dst.sa.sa_family = family;
 612         if (family == AF_INET)
 613                 memcpy(&lookup->results[n].dst.sin.sin_addr,
 614                                                 data, NS_INADDRSZ);
 615         else
 616                 memcpy(&lookup->results[n].dst.sin6.sin6_addr,
 617                                                 data, NS_IN6ADDRSZ);
 618 }
 619
 620 static void parse_response(struct resolv_nameserver *nameserver,
 621                                         const unsigned char *buf, int len)
 622 {
 623         GResolv *resolv = nameserver->resolv;
 624         GResolvResultStatus status;
 625         struct resolv_query *query;
 626         struct resolv_lookup *lookup;
 627         GList *list;
 628         ns_msg msg;
 629         ns_rr rr;
 630         int i, rcode, count;
 631
 632         debug(resolv, "response from %s", nameserver->address);
 633
 634         ns_initparse(buf, len, &msg);
 635
 636         rcode = ns_msg_getflag(msg, ns_f_rcode);
 637         count = ns_msg_count(msg, ns_s_an);
 638
 639         debug(resolv, "msg id: 0x%04x rcode: %d count: %d",
 640                                         ns_msg_id(msg), rcode, count);
 641
 642         switch (rcode) {
 643         case 0:
 644                 status = G_RESOLV_RESULT_STATUS_SUCCESS;
 645                 break;
 646         case 1:
 647                 status = G_RESOLV_RESULT_STATUS_FORMAT_ERROR;
 648                 break;
 649         case 2:
 650                 status = G_RESOLV_RESULT_STATUS_SERVER_FAILURE;
 651                 break;
 652         case 3:
 653                 status = G_RESOLV_RESULT_STATUS_NAME_ERROR;
 654                 break;
 655         case 4:
 656                 status = G_RESOLV_RESULT_STATUS_NOT_IMPLEMENTED;
 657                 break;
 658         case 5:
 659                 status = G_RESOLV_RESULT_STATUS_REFUSED;
 660                 break;
 661         default:
 662                 status = G_RESOLV_RESULT_STATUS_ERROR;
 663                 break;
 664         }
 665
 666         list = g_queue_find_custom(resolv->query_queue,
 667                         GUINT_TO_POINTER(ns_msg_id(msg)), compare_query_msgid);
 668         if (!list)
 669                 return;
 670
 671         query = list->data;
 672         lookup = query->lookup;
 673
 674         if (query == lookup->ipv6_query) {
 675                 lookup->ipv6_status = status;
 676                 lookup->ipv6_query = NULL;
 677         } else if (query == lookup->ipv4_query) {
 678                 lookup->ipv4_status = status;
 679                 lookup->ipv4_query = NULL;
 680         }
 681
 682         for (i = 0; i < count; i++) {
 683                 ns_parserr(&msg, ns_s_an, i, &rr);
 684
 685                 if (ns_rr_class(rr) != ns_c_in)
 686                         continue;
 687
 688                 g_assert(offsetof(struct sockaddr_in, sin_addr) ==
 689                                 offsetof(struct sockaddr_in6, sin6_flowinfo));
 690
 691                 if (ns_rr_type(rr) == ns_t_a &&
 692                                         ns_rr_rdlen(rr) == NS_INADDRSZ) {
 693                         add_result(lookup, AF_INET, ns_rr_rdata(rr));
 694                 } else if (ns_rr_type(rr) == ns_t_aaaa &&
 695                                         ns_rr_rdlen(rr) == NS_IN6ADDRSZ) {
 696                         add_result(lookup, AF_INET6, ns_rr_rdata(rr));
 697                 }
 698         }
 699
 700         if (lookup->ipv4_query == NULL && lookup->ipv6_query == NULL)
 701                 sort_and_return_results(lookup);
 702
 703         destroy_query(query);
 704         g_queue_remove(resolv->query_queue, query);
 705 }
 706
 707 static gboolean received_udp_data(GIOChannel *channel, GIOCondition cond,
 708                                                         gpointer user_data)
 709 {
 710         struct resolv_nameserver *nameserver = user_data;
 711         unsigned char buf[4096];
 712         int sk, len;
 713
 714         if (cond & (G_IO_NVAL | G_IO_ERR | G_IO_HUP)) {
 715                 nameserver->udp_watch = 0;
 716                 return FALSE;
 717         }
 718
 719         sk = g_io_channel_unix_get_fd(nameserver->udp_channel);
 720
 721         len = recv(sk, buf, sizeof(buf), 0);
 722         if (len < 12)
 723                 return TRUE;
 724
 725         parse_response(nameserver, buf, len);
 726
 727         return TRUE;
 728 }
 729
 730 static int connect_udp_channel(struct resolv_nameserver *nameserver)
 731 {
 732         struct addrinfo hints, *rp;
 733         char portnr[6];
 734         int err, sk;
 735
 736         memset(&hints, 0, sizeof(hints));
 737         hints.ai_family = AF_UNSPEC;
 738         hints.ai_socktype = SOCK_DGRAM;
 739         hints.ai_flags = AI_PASSIVE | AI_NUMERICSERV | AI_NUMERICHOST;
 740
 741         sprintf(portnr, "%d", nameserver->port);
 742         err = getaddrinfo(nameserver->address, portnr, &hints, &rp);
 743         if (err)
 744                 return -EINVAL;
 745
 746         /*
 747          * Do not blindly copy this code elsewhere; it doesn't loop over the
 748          * results using ->ai_next as it should. That's OK in *this* case
 749          * because it was a numeric lookup; we *know* there's only one.
 750          */
 751         if (!rp)
 752                 return -EINVAL;
 753
 754         sk = socket(rp->ai_family, rp->ai_socktype, rp->ai_protocol);
 755         if (sk < 0) {
 756                 freeaddrinfo(rp);
 757                 return -EIO;
 758         }
 759
 760         if (connect(sk, rp->ai_addr, rp->ai_addrlen) < 0) {
 761                 close(sk);
 762                 freeaddrinfo(rp);
 763                 return -EIO;
 764         }
 765
 766         freeaddrinfo(rp);
 767
 768         nameserver->udp_channel = g_io_channel_unix_new(sk);
 769         if (nameserver->udp_channel == NULL) {
 770                 close(sk);
 771                 return -ENOMEM;
 772         }
 773
 774         g_io_channel_set_close_on_unref(nameserver->udp_channel, TRUE);
 775
 776         nameserver->udp_watch = g_io_add_watch(nameserver->udp_channel,
 777                                 G_IO_IN | G_IO_NVAL | G_IO_ERR | G_IO_HUP,
 778                                 received_udp_data, nameserver);
 779
 780         return 0;
 781 }
 782
 783 GResolv *g_resolv_new(int index)
 784 {
 785         GResolv *resolv;
 786
 787         if (index < 0)
 788                 return NULL;
 789
 790         resolv = g_try_new0(GResolv, 1);
 791         if (resolv == NULL)
 792                 return NULL;
 793
 794         resolv->ref_count = 1;
 795
 796         resolv->result_family = AF_UNSPEC;
 797
 798         resolv->next_lookup_id = 1;
 799
 800         resolv->query_queue = g_queue_new();
 801         if (resolv->query_queue == NULL) {
 802                 g_free(resolv);
 803                 return NULL;
 804         }
 805
 806         resolv->lookup_queue = g_queue_new();
 807         if (resolv->lookup_queue == NULL) {
 808                 g_queue_free(resolv->query_queue);
 809                 g_free(resolv);
 810                 return NULL;
 811         }
 812
 813         resolv->index = index;
 814         resolv->nameserver_list = NULL;
 815
 816         res_ninit(&resolv->res);
 817
 818         return resolv;
 819 }
 820
 821 GResolv *g_resolv_ref(GResolv *resolv)
 822 {
 823         if (resolv == NULL)
 824                 return NULL;
 825
 826         g_atomic_int_inc(&resolv->ref_count);
 827
 828         return resolv;
 829 }
 830
 831 void g_resolv_unref(GResolv *resolv)
 832 {
 833         struct resolv_query *query;
 834
 835         if (resolv == NULL)
 836                 return;
 837
 838         if (g_atomic_int_dec_and_test(&resolv->ref_count) == FALSE)
 839                 return;
 840
 841         while ((query = g_queue_pop_head(resolv->query_queue)))
 842                 destroy_query(query);
 843
 844         g_queue_free(resolv->query_queue);
 845         g_queue_free(resolv->lookup_queue);
 846
 847         flush_nameservers(resolv);
 848
 849         res_nclose(&resolv->res);
 850
 851         g_free(resolv);
 852 }
 853
 854 void g_resolv_set_debug(GResolv *resolv, GResolvDebugFunc func,
 855                                                 gpointer user_data)
 856 {
 857         if (resolv == NULL)
 858                 return;
 859
 860         resolv->debug_func = func;
 861         resolv->debug_data = user_data;
 862 }
 863
 864 gboolean g_resolv_add_nameserver(GResolv *resolv, const char *address,
 865                                         uint16_t port, unsigned long flags)
 866 {
 867         struct resolv_nameserver *nameserver;
 868
 869         if (resolv == NULL)
 870                 return FALSE;
 871
 872         nameserver = g_try_new0(struct resolv_nameserver, 1);
 873         if (nameserver == NULL)
 874                 return FALSE;
 875
 876         nameserver->address = g_strdup(address);
 877         nameserver->port = port;
 878         nameserver->flags = flags;
 879
 880         if (connect_udp_channel(nameserver) < 0) {
 881                 free_nameserver(nameserver);
 882                 return FALSE;
 883         }
 884
 885         nameserver->resolv = resolv;
 886
 887         resolv->nameserver_list = g_list_append(resolv->nameserver_list,
 888                                                                 nameserver);
 889
 890         debug(resolv, "setting nameserver %s", address);
 891
 892         return TRUE;
 893 }
 894
 895 void g_resolv_flush_nameservers(GResolv *resolv)
 896 {
 897         if (resolv == NULL)
 898                 return;
 899
 900         flush_nameservers(resolv);
 901 }
 902
 903 static gint add_query(struct resolv_lookup *lookup, const char *hostname, int type)
 904 {
 905         struct resolv_query *query = g_try_new0(struct resolv_query, 1);
 906         unsigned char buf[4096];
 907         int len;
 908
 909         if (query == NULL)
 910                 return -ENOMEM;
 911
 912         len = res_mkquery(ns_o_query, hostname, ns_c_in, type,
 913                                         NULL, 0, NULL, buf, sizeof(buf));
 914
 915         query->msgid = buf[0] << 8 | buf[1];
 916
 917         if (send_query(lookup->resolv, buf, len) < 0) {
 918                 g_free(query);
 919                 return -EIO;
 920         }
 921
 922         query->resolv = lookup->resolv;
 923         query->lookup = lookup;
 924
 925         g_queue_push_tail(lookup->resolv->query_queue, query);
 926
 927         query->timeout = g_timeout_add_seconds(5, query_timeout, query);
 928
 929         if (type == ns_t_aaaa)
 930                 lookup->ipv6_query = query;
 931         else
 932                 lookup->ipv4_query = query;
 933
 934         return 0;
 935 }
 936
 937 guint g_resolv_lookup_hostname(GResolv *resolv, const char *hostname,
 938                                 GResolvResultFunc func, gpointer user_data)
 939 {
 940         struct resolv_lookup *lookup;
 941
 942         debug(resolv, "lookup hostname %s", hostname);
 943
 944         if (resolv == NULL)
 945                 return 0;
 946
 947         if (resolv->nameserver_list == NULL) {
 948                 int i;
 949
 950                 for (i = 0; i < resolv->res.nscount; i++) {
 951                         char buf[100];
 952                         int family = resolv->res.nsaddr_list[i].sin_family;
 953                         void *sa_addr = &resolv->res.nsaddr_list[i].sin_addr;
 954
 955                         if (family != AF_INET &&
 956                                         resolv->res._u._ext.nsaddrs[i]) {
 957                                 family = AF_INET6;
 958                                 sa_addr = &resolv->res._u._ext.nsaddrs[i]->sin6_addr;
 959                         }
 960
 961                         if (family != AF_INET && family != AF_INET6)
 962                                 continue;
 963
 964                         if (inet_ntop(family, sa_addr, buf, sizeof(buf)))
 965                                 g_resolv_add_nameserver(resolv, buf, 53, 0);
 966                 }
 967
 968                 if (resolv->nameserver_list == NULL)
 969                         g_resolv_add_nameserver(resolv, "127.0.0.1", 53, 0);
 970         }
 971
 972         lookup = g_try_new0(struct resolv_lookup, 1);
 973         if (lookup == NULL)
 974                 return 0;
 975
 976         lookup->resolv = resolv;
 977         lookup->result_func = func;
 978         lookup->result_data = user_data;
 979         lookup->id = resolv->next_lookup_id++;
 980
 981         if (resolv->result_family != AF_INET6) {
 982                 if (add_query(lookup, hostname, ns_t_a)) {
 983                         g_free(lookup);
 984                         return -EIO;
 985                 }
 986         }
 987
 988         if (resolv->result_family != AF_INET) {
 989                 if (add_query(lookup, hostname, ns_t_aaaa)) {
 990                         if (resolv->result_family != AF_INET6) {
 991                                 destroy_query(lookup->ipv4_query);
 992                                 g_queue_remove(resolv->query_queue,
 993                                                 lookup->ipv4_query);
 994                         }
 995
 996                         g_free(lookup);
 997                         return -EIO;
 998                 }
 999         }
1000
1001         g_queue_push_tail(resolv->lookup_queue, lookup);
1002         return lookup->id;
1003 }
1004
1005 gboolean g_resolv_cancel_lookup(GResolv *resolv, guint id)
1006 {
1007         GList *list;
1008
1009         list = g_queue_find_custom(resolv->lookup_queue,
1010                                 GUINT_TO_POINTER(id), compare_lookup_id);
1011
1012         if (list == NULL)
1013                 return FALSE;
1014
1015         destroy_lookup(list->data);
1016         g_queue_remove(resolv->query_queue, list->data);
1017
1018         return TRUE;
1019 }
1020
1021 gboolean g_resolv_set_address_family(GResolv *resolv, int family)
1022 {
1023         if (resolv == NULL)
1024                 return FALSE;
1025
1026         if (family != AF_UNSPEC && family != AF_INET && family != AF_INET6)
1027                 return FALSE;
1028
1029         resolv->result_family = family;
1030
1031         return TRUE;
1032 }