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         int 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 | SOCK_CLOEXEC,
 165                         IPPROTO_IP);
 166         if (fd < 0)
 167                 return;
 168
 169         if (connect(fd, &res->dst.sa, sizeof(res->dst)) < 0) {
 170                 close(fd);
 171                 return;
 172         }
 173
 174         if (getsockname(fd, &res->src.sa, &sl) < 0) {
 175                 close(fd);
 176                 return;
 177         }
 178
 179         res->reachable = TRUE;
 180         close(fd);
 181 }
 182
 183 struct gai_table
 184 {
 185         unsigned char addr[NS_IN6ADDRSZ];
 186         int mask;
 187         int value;
 188 };
 189
 190 static const struct gai_table gai_labels[] = {
 191         {
 192                 .addr = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 193                           0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01 },
 194                 .mask = 128,
 195                 .value = 0,
 196         }, {
 197                 .addr = { 0x20, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 198                           0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
 199                 .mask = 16,
 200                 .value = 2,
 201         }, {
 202                 .addr = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 203                           0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
 204                 .mask = 96,
 205                 .value = 3,
 206         }, {
 207                 .addr = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 208                           0x00, 0x00, 0xff, 0xff, 0x00, 0x00, 0x00, 0x00 },
 209                 .mask = 96,
 210                 .value = 4,
 211         }, {
 212                 /* Variations from RFC 3484, matching glibc behaviour */
 213                 .addr = { 0xfe, 0xc0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 214                           0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
 215                 .mask = 10,
 216                 .value = 5,
 217         }, {
 218                 .addr = { 0xfc, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 219                           0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
 220                 .mask = 7,
 221                 .value = 6,
 222         }, {
 223                 .addr = { 0x20, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 224                           0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
 225                 .mask = 32,
 226                 .value = 7,
 227         }, {
 228                 /* catch-all */
 229                 .addr = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 230                           0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
 231                 .mask = 0,
 232                 .value = 1,
 233         }
 234 };
 235
 236 static const struct gai_table gai_precedences[] = {
 237         {
 238                 .addr = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 239                           0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01 },
 240                 .mask = 128,
 241                 .value = 50,
 242         }, {
 243                 .addr = { 0x20, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 244                           0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
 245                 .mask = 16,
 246                 .value = 30,
 247         }, {
 248                 .addr = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 249                           0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
 250                 .mask = 96,
 251                 .value = 20,
 252         }, {
 253                 .addr = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 254                           0x00, 0x00, 0xff, 0xff, 0x00, 0x00, 0x00, 0x00 },
 255                 .mask = 96,
 256                 .value = 10,
 257         }, {
 258                 .addr = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 259                           0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
 260                 .mask = 0,
 261                 .value = 40,
 262         }
 263 };
 264
 265 static unsigned char v4mapped[] = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 266                                     0x00, 0x00, 0xff, 0xff, 0x00, 0x00, 0x00, 0x00 };
 267
 268 static gboolean mask_compare(const unsigned char *one,
 269                                         const unsigned char *two, int mask)
 270 {
 271         if (mask > 8) {
 272                 if (memcmp(one, two, mask / 8))
 273                         return FALSE;
 274                 one += mask / 8;
 275                 two += mask / 8;
 276                 mask %= 8;
 277         }
 278
 279         if (mask && ((*one ^ *two) >> (8 - mask)))
 280                 return FALSE;
 281
 282         return TRUE;
 283 }
 284
 285 static int match_gai_table(struct sockaddr *sa, const struct gai_table *tbl)
 286 {
 287         struct sockaddr_in *sin = (void *)sa;
 288         struct sockaddr_in6 *sin6 = (void *)sa;
 289         void *addr;
 290
 291         if (sa->sa_family == AF_INET) {
 292                 addr = v4mapped;
 293                 memcpy(v4mapped+12, &sin->sin_addr, NS_INADDRSZ);
 294         } else
 295                 addr = &sin6->sin6_addr;
 296
 297         while (1) {
 298                 if (mask_compare(addr, tbl->addr, tbl->mask))
 299                         return tbl->value;
 300                 tbl++;
 301         }
 302 }
 303
 304 #define DQUAD(_a,_b,_c,_d) ( ((_a)<<24) | ((_b)<<16) | ((_c)<<8) | (_d) )
 305 #define V4MATCH(addr, a,b,c,d, m) ( ((addr) ^ DQUAD(a,b,c,d)) >> (32 - (m)) )
 306
 307 #define RFC3484_SCOPE_LINK      2
 308 #define RFC3484_SCOPE_SITE      5
 309 #define RFC3484_SCOPE_GLOBAL    14
 310
 311 static int addr_scope(struct sockaddr *sa)
 312 {
 313         if (sa->sa_family == AF_INET) {
 314                 struct sockaddr_in *sin = (void *)sa;
 315                 guint32 addr = ntohl(sin->sin_addr.s_addr);
 316
 317                 if (V4MATCH(addr, 169,254,0,0, 16) ||
 318                                         V4MATCH(addr, 127,0,0,0, 8))
 319                         return RFC3484_SCOPE_LINK;
 320
 321                 /* Site-local */
 322                 if (V4MATCH(addr, 10,0,0,0, 8) ||
 323                                 V4MATCH(addr, 172,16,0,0, 12) ||
 324                                 V4MATCH(addr, 192,168,0,0, 16))
 325                         return RFC3484_SCOPE_SITE;
 326
 327                 /* Global */
 328                 return RFC3484_SCOPE_GLOBAL;
 329         } else {
 330                 struct sockaddr_in6 *sin6 = (void *)sa;
 331
 332                 /* Multicast addresses have a 4-bit scope field */
 333                 if (IN6_IS_ADDR_MULTICAST(&sin6->sin6_addr))
 334                         return sin6->sin6_addr.s6_addr[1] & 0xf;
 335
 336                 if (IN6_IS_ADDR_LINKLOCAL(&sin6->sin6_addr) ||
 337                                 IN6_IS_ADDR_LOOPBACK(&sin6->sin6_addr))
 338                         return RFC3484_SCOPE_LINK;
 339
 340                 if (IN6_IS_ADDR_SITELOCAL(&sin6->sin6_addr))
 341                         return RFC3484_SCOPE_SITE;
 342
 343                 return RFC3484_SCOPE_GLOBAL;
 344         }
 345 }
 346
 347 static int rfc3484_compare(const void *__one, const void *__two)
 348 {
 349         const struct sort_result *one = __one;
 350         const struct sort_result *two = __two;
 351
 352         /* Rule 1: Avoid unusable destinations */
 353         if (one->reachable && !two->reachable)
 354                 return -1;
 355         else if (two->reachable && !one->reachable)
 356                 return 1;
 357
 358         /* Rule 2: Prefer matching scope */
 359         if (one->dst_scope == one->src_scope &&
 360                                 two->dst_scope != two->src_scope)
 361                 return -1;
 362         else if (two->dst_scope == two->src_scope &&
 363                                 one->dst_scope != one->src_scope)
 364                 return 1;
 365
 366         /* Rule 3: Avoid deprecated addresses */
 367
 368         /* Rule 4: Prefer home addresses */
 369
 370         /* Rule 5: Prefer matching label */
 371         if (one->dst_label == one->src_label &&
 372                                 two->dst_label != two->src_label)
 373                 return -1;
 374         else if (two->dst_label == two->src_label &&
 375                                 one->dst_label != one->src_label)
 376                 return 1;
 377
 378         /* Rule 6: Prefer higher precedence */
 379         if (one->precedence > two->precedence)
 380                 return -1;
 381         else if (two->precedence > one->precedence)
 382                 return 1;
 383
 384         /* Rule 7: Prefer native transport */
 385
 386         /* Rule 8: Prefer smaller scope */
 387         if (one->dst_scope != two->dst_scope)
 388                 return one->dst_scope - two->dst_scope;
 389
 390         /* Rule 9: Use longest matching prefix */
 391         if (one->dst.sa.sa_family == AF_INET) {
 392                 /*
 393                  * Rule 9 is meaningless and counterproductive for Legacy IP
 394                  * unless perhaps we can tell that it's actually on the local
 395                  * subnet. But we don't (yet) have local interface config
 396                  * information, so do nothing here for Legacy IP for now.
 397                  */
 398         } else {
 399                 int i;
 400
 401                 for (i = 0; i < 4; i++) {
 402                         guint32 cmp_one, cmp_two;
 403
 404                         cmp_one = one->src.sin6.sin6_addr.s6_addr32[i] ^
 405                                         one->dst.sin6.sin6_addr.s6_addr32[i];
 406                         cmp_two = two->src.sin6.sin6_addr.s6_addr32[i] ^
 407                                         two->dst.sin6.sin6_addr.s6_addr32[i];
 408
 409                         if (!cmp_two && !cmp_one)
 410                                 continue;
 411
 412                         if (cmp_one && !cmp_two)
 413                                 return 1;
 414                         if (cmp_two && !cmp_one)
 415                                 return -1;
 416
 417                         /* g_bit_storage() is effectively fls() */
 418                         cmp_one = g_bit_storage(ntohl(cmp_one));
 419                         cmp_two = g_bit_storage(ntohl(cmp_two));
 420
 421                         if (cmp_one == cmp_two)
 422                                 break;
 423
 424                         return cmp_one - cmp_two;
 425                 }
 426         }
 427
 428
 429         /* Rule 10: Otherwise, leave the order unchanged */
 430         if (one < two)
 431                 return -1;
 432         else
 433                 return 1;
 434 }
 435
 436 static void rfc3484_sort_results(struct resolv_lookup *lookup)
 437 {
 438         int i;
 439
 440         for (i = 0; i < lookup->nr_results; i++) {
 441                 struct sort_result *res = &lookup->results[i];
 442                 find_srcaddr(res);
 443                 res->precedence = match_gai_table(&res->dst.sa,
 444                                                         gai_precedences);
 445                 res->dst_label = match_gai_table(&res->dst.sa, gai_labels);
 446                 res->src_label = match_gai_table(&res->src.sa, gai_labels);
 447                 res->dst_scope = addr_scope(&res->dst.sa);
 448                 res->src_scope = addr_scope(&res->src.sa);
 449         }
 450
 451         qsort(lookup->results, lookup->nr_results,
 452                         sizeof(struct sort_result), rfc3484_compare);
 453 }
 454
 455 static void sort_and_return_results(struct resolv_lookup *lookup)
 456 {
 457         char buf[INET6_ADDRSTRLEN + 1];
 458         GResolvResultStatus status;
 459         char **results = g_try_new0(char *, lookup->nr_results + 1);
 460         int i, n = 0;
 461
 462         if (!results)
 463                 return;
 464
 465         memset(buf, 0, INET6_ADDRSTRLEN + 1);
 466
 467         rfc3484_sort_results(lookup);
 468
 469         for (i = 0; i < lookup->nr_results; i++) {
 470                 if (lookup->results[i].dst.sa.sa_family == AF_INET) {
 471                         if (inet_ntop(AF_INET,
 472                                         &lookup->results[i].dst.sin.sin_addr,
 473                                         buf, sizeof(buf) - 1) == NULL)
 474                                 continue;
 475                 } else if (lookup->results[i].dst.sa.sa_family == AF_INET6) {
 476                         if (inet_ntop(AF_INET6,
 477                                         &lookup->results[i].dst.sin6.sin6_addr,
 478                                         buf, sizeof(buf) - 1) == NULL)
 479                                 continue;
 480                 } else
 481                         continue;
 482
 483                 results[n++] = strdup(buf);
 484         }
 485
 486         results[n++] = NULL;
 487
 488         status = lookup->ipv4_status;
 489
 490         if (status == G_RESOLV_RESULT_STATUS_SUCCESS)
 491                 status = lookup->ipv6_status;
 492
 493         lookup->result_func(status, results, lookup->result_data);
 494
 495         g_strfreev(results);
 496         g_queue_remove(lookup->resolv->lookup_queue, lookup);
 497         destroy_lookup(lookup);
 498 }
 499
 500 static gboolean query_timeout(gpointer user_data)
 501 {
 502         struct resolv_query *query = user_data;
 503         struct resolv_lookup *lookup = query->lookup;
 504         GResolv *resolv = query->resolv;
 505
 506         query->timeout = 0;
 507
 508         if (query == lookup->ipv4_query) {
 509                 lookup->ipv4_status = G_RESOLV_RESULT_STATUS_NO_RESPONSE;
 510                 lookup->ipv4_query = NULL;
 511         } else if (query == lookup->ipv6_query) {
 512                 lookup->ipv6_status = G_RESOLV_RESULT_STATUS_NO_RESPONSE;
 513                 lookup->ipv6_query = NULL;
 514         }
 515
 516         if (lookup->ipv4_query == NULL && lookup->ipv4_query == NULL)
 517                 sort_and_return_results(lookup);
 518
 519         destroy_query(query);
 520         g_queue_remove(resolv->query_queue, query);
 521
 522         return FALSE;
 523 }
 524
 525 static void free_nameserver(struct resolv_nameserver *nameserver)
 526 {
 527         if (nameserver == NULL)
 528                 return;
 529
 530         if (nameserver->udp_watch > 0)
 531                 g_source_remove(nameserver->udp_watch);
 532
 533         if (nameserver->udp_channel != NULL)
 534                 g_io_channel_unref(nameserver->udp_channel);
 535
 536         g_free(nameserver->address);
 537         g_free(nameserver);
 538 }
 539
 540 static void flush_nameservers(GResolv *resolv)
 541 {
 542         GList *list;
 543
 544         for (list = g_list_first(resolv->nameserver_list);
 545                                         list; list = g_list_next(list))
 546                 free_nameserver(list->data);
 547
 548         g_list_free(resolv->nameserver_list);
 549         resolv->nameserver_list = NULL;
 550 }
 551
 552 static int send_query(GResolv *resolv, const unsigned char *buf, int len)
 553 {
 554         GList *list;
 555
 556         if (resolv->nameserver_list == NULL)
 557                 return -ENOENT;
 558
 559         for (list = g_list_first(resolv->nameserver_list);
 560                                         list; list = g_list_next(list)) {
 561                 struct resolv_nameserver *nameserver = list->data;
 562                 int sk, sent;
 563
 564                 if (nameserver->udp_channel == NULL)
 565                         continue;
 566
 567                 sk = g_io_channel_unix_get_fd(nameserver->udp_channel);
 568
 569                 sent = send(sk, buf, len, 0);
 570                 if (sent < 0)
 571                         continue;
 572         }
 573
 574         return 0;
 575 }
 576
 577 static gint compare_lookup_id(gconstpointer a, gconstpointer b)
 578 {
 579         const struct resolv_lookup *lookup = a;
 580         guint id = GPOINTER_TO_UINT(b);
 581
 582         if (lookup->id < id)
 583                 return -1;
 584
 585         if (lookup->id > id)
 586                 return 1;
 587
 588         return 0;
 589 }
 590
 591 static gint compare_query_msgid(gconstpointer a, gconstpointer b)
 592 {
 593         const struct resolv_query *query = a;
 594         uint16_t msgid = GPOINTER_TO_UINT(b);
 595
 596         if (query->msgid < msgid)
 597                 return -1;
 598
 599         if (query->msgid > msgid)
 600                 return 1;
 601
 602         return 0;
 603 }
 604
 605 static void add_result(struct resolv_lookup *lookup, int family,
 606                                                         const void *data)
 607 {
 608         int n = lookup->nr_results++;
 609         lookup->results = g_realloc(lookup->results,
 610                                         sizeof(struct sort_result) * (n + 1));
 611
 612         memset(&lookup->results[n], 0, sizeof(struct sort_result));
 613
 614         lookup->results[n].dst.sa.sa_family = family;
 615         if (family == AF_INET)
 616                 memcpy(&lookup->results[n].dst.sin.sin_addr,
 617                                                 data, NS_INADDRSZ);
 618         else
 619                 memcpy(&lookup->results[n].dst.sin6.sin6_addr,
 620                                                 data, NS_IN6ADDRSZ);
 621 }
 622
 623 static void parse_response(struct resolv_nameserver *nameserver,
 624                                         const unsigned char *buf, int len)
 625 {
 626         GResolv *resolv = nameserver->resolv;
 627         GResolvResultStatus status;
 628         struct resolv_query *query;
 629         struct resolv_lookup *lookup;
 630         GList *list;
 631         ns_msg msg;
 632         ns_rr rr;
 633         int i, rcode, count;
 634
 635         debug(resolv, "response from %s", nameserver->address);
 636
 637         ns_initparse(buf, len, &msg);
 638
 639         rcode = ns_msg_getflag(msg, ns_f_rcode);
 640         count = ns_msg_count(msg, ns_s_an);
 641
 642         debug(resolv, "msg id: 0x%04x rcode: %d count: %d",
 643                                         ns_msg_id(msg), rcode, count);
 644
 645         switch (rcode) {
 646         case 0:
 647                 status = G_RESOLV_RESULT_STATUS_SUCCESS;
 648                 break;
 649         case 1:
 650                 status = G_RESOLV_RESULT_STATUS_FORMAT_ERROR;
 651                 break;
 652         case 2:
 653                 status = G_RESOLV_RESULT_STATUS_SERVER_FAILURE;
 654                 break;
 655         case 3:
 656                 status = G_RESOLV_RESULT_STATUS_NAME_ERROR;
 657                 break;
 658         case 4:
 659                 status = G_RESOLV_RESULT_STATUS_NOT_IMPLEMENTED;
 660                 break;
 661         case 5:
 662                 status = G_RESOLV_RESULT_STATUS_REFUSED;
 663                 break;
 664         default:
 665                 status = G_RESOLV_RESULT_STATUS_ERROR;
 666                 break;
 667         }
 668
 669         list = g_queue_find_custom(resolv->query_queue,
 670                         GUINT_TO_POINTER(ns_msg_id(msg)), compare_query_msgid);
 671         if (!list)
 672                 return;
 673
 674         query = list->data;
 675         lookup = query->lookup;
 676
 677         if (query == lookup->ipv6_query) {
 678                 lookup->ipv6_status = status;
 679                 lookup->ipv6_query = NULL;
 680         } else if (query == lookup->ipv4_query) {
 681                 lookup->ipv4_status = status;
 682                 lookup->ipv4_query = NULL;
 683         }
 684
 685         for (i = 0; i < count; i++) {
 686                 ns_parserr(&msg, ns_s_an, i, &rr);
 687
 688                 if (ns_rr_class(rr) != ns_c_in)
 689                         continue;
 690
 691                 g_assert(offsetof(struct sockaddr_in, sin_addr) ==
 692                                 offsetof(struct sockaddr_in6, sin6_flowinfo));
 693
 694                 if (ns_rr_type(rr) == ns_t_a &&
 695                                         ns_rr_rdlen(rr) == NS_INADDRSZ) {
 696                         add_result(lookup, AF_INET, ns_rr_rdata(rr));
 697                 } else if (ns_rr_type(rr) == ns_t_aaaa &&
 698                                         ns_rr_rdlen(rr) == NS_IN6ADDRSZ) {
 699                         add_result(lookup, AF_INET6, ns_rr_rdata(rr));
 700                 }
 701         }
 702
 703         if (lookup->ipv4_query == NULL && lookup->ipv6_query == NULL)
 704                 sort_and_return_results(lookup);
 705
 706         destroy_query(query);
 707         g_queue_remove(resolv->query_queue, query);
 708 }
 709
 710 static gboolean received_udp_data(GIOChannel *channel, GIOCondition cond,
 711                                                         gpointer user_data)
 712 {
 713         struct resolv_nameserver *nameserver = user_data;
 714         unsigned char buf[4096];
 715         int sk, len;
 716
 717         if (cond & (G_IO_NVAL | G_IO_ERR | G_IO_HUP)) {
 718                 nameserver->udp_watch = 0;
 719                 return FALSE;
 720         }
 721
 722         sk = g_io_channel_unix_get_fd(nameserver->udp_channel);
 723
 724         len = recv(sk, buf, sizeof(buf), 0);
 725         if (len < 12)
 726                 return TRUE;
 727
 728         parse_response(nameserver, buf, len);
 729
 730         return TRUE;
 731 }
 732
 733 static int connect_udp_channel(struct resolv_nameserver *nameserver)
 734 {
 735         struct addrinfo hints, *rp;
 736         char portnr[6];
 737         int err, sk;
 738
 739         memset(&hints, 0, sizeof(hints));
 740         hints.ai_family = AF_UNSPEC;
 741         hints.ai_socktype = SOCK_DGRAM;
 742         hints.ai_flags = AI_PASSIVE | AI_NUMERICSERV | AI_NUMERICHOST;
 743
 744         sprintf(portnr, "%d", nameserver->port);
 745         err = getaddrinfo(nameserver->address, portnr, &hints, &rp);
 746         if (err)
 747                 return -EINVAL;
 748
 749         /*
 750          * Do not blindly copy this code elsewhere; it doesn't loop over the
 751          * results using ->ai_next as it should. That's OK in *this* case
 752          * because it was a numeric lookup; we *know* there's only one.
 753          */
 754         if (!rp)
 755                 return -EINVAL;
 756
 757         sk = socket(rp->ai_family, rp->ai_socktype, rp->ai_protocol);
 758         if (sk < 0) {
 759                 freeaddrinfo(rp);
 760                 return -EIO;
 761         }
 762
 763         if (connect(sk, rp->ai_addr, rp->ai_addrlen) < 0) {
 764                 close(sk);
 765                 freeaddrinfo(rp);
 766                 return -EIO;
 767         }
 768
 769         freeaddrinfo(rp);
 770
 771         nameserver->udp_channel = g_io_channel_unix_new(sk);
 772         if (nameserver->udp_channel == NULL) {
 773                 close(sk);
 774                 return -ENOMEM;
 775         }
 776
 777         g_io_channel_set_close_on_unref(nameserver->udp_channel, TRUE);
 778
 779         nameserver->udp_watch = g_io_add_watch(nameserver->udp_channel,
 780                                 G_IO_IN | G_IO_NVAL | G_IO_ERR | G_IO_HUP,
 781                                 received_udp_data, nameserver);
 782
 783         return 0;
 784 }
 785
 786 GResolv *g_resolv_new(int index)
 787 {
 788         GResolv *resolv;
 789
 790         if (index < 0)
 791                 return NULL;
 792
 793         resolv = g_try_new0(GResolv, 1);
 794         if (resolv == NULL)
 795                 return NULL;
 796
 797         resolv->ref_count = 1;
 798
 799         resolv->result_family = AF_UNSPEC;
 800
 801         resolv->next_lookup_id = 1;
 802
 803         resolv->query_queue = g_queue_new();
 804         if (resolv->query_queue == NULL) {
 805                 g_free(resolv);
 806                 return NULL;
 807         }
 808
 809         resolv->lookup_queue = g_queue_new();
 810         if (resolv->lookup_queue == NULL) {
 811                 g_queue_free(resolv->query_queue);
 812                 g_free(resolv);
 813                 return NULL;
 814         }
 815
 816         resolv->index = index;
 817         resolv->nameserver_list = NULL;
 818
 819         res_ninit(&resolv->res);
 820
 821         return resolv;
 822 }
 823
 824 GResolv *g_resolv_ref(GResolv *resolv)
 825 {
 826         if (resolv == NULL)
 827                 return NULL;
 828
 829         __sync_fetch_and_add(&resolv->ref_count, 1);
 830
 831         return resolv;
 832 }
 833
 834 void g_resolv_unref(GResolv *resolv)
 835 {
 836         struct resolv_query *query;
 837
 838         if (resolv == NULL)
 839                 return;
 840
 841         if (__sync_fetch_and_sub(&resolv->ref_count, 1) != 1)
 842                 return;
 843
 844         while ((query = g_queue_pop_head(resolv->query_queue)))
 845                 destroy_query(query);
 846
 847         g_queue_free(resolv->query_queue);
 848         g_queue_free(resolv->lookup_queue);
 849
 850         flush_nameservers(resolv);
 851
 852         res_nclose(&resolv->res);
 853
 854         g_free(resolv);
 855 }
 856
 857 void g_resolv_set_debug(GResolv *resolv, GResolvDebugFunc func,
 858                                                 gpointer user_data)
 859 {
 860         if (resolv == NULL)
 861                 return;
 862
 863         resolv->debug_func = func;
 864         resolv->debug_data = user_data;
 865 }
 866
 867 gboolean g_resolv_add_nameserver(GResolv *resolv, const char *address,
 868                                         uint16_t port, unsigned long flags)
 869 {
 870         struct resolv_nameserver *nameserver;
 871
 872         if (resolv == NULL)
 873                 return FALSE;
 874
 875         nameserver = g_try_new0(struct resolv_nameserver, 1);
 876         if (nameserver == NULL)
 877                 return FALSE;
 878
 879         nameserver->address = g_strdup(address);
 880         nameserver->port = port;
 881         nameserver->flags = flags;
 882
 883         if (connect_udp_channel(nameserver) < 0) {
 884                 free_nameserver(nameserver);
 885                 return FALSE;
 886         }
 887
 888         nameserver->resolv = resolv;
 889
 890         resolv->nameserver_list = g_list_append(resolv->nameserver_list,
 891                                                                 nameserver);
 892
 893         debug(resolv, "setting nameserver %s", address);
 894
 895         return TRUE;
 896 }
 897
 898 void g_resolv_flush_nameservers(GResolv *resolv)
 899 {
 900         if (resolv == NULL)
 901                 return;
 902
 903         flush_nameservers(resolv);
 904 }
 905
 906 static gint add_query(struct resolv_lookup *lookup, const char *hostname, int type)
 907 {
 908         struct resolv_query *query = g_try_new0(struct resolv_query, 1);
 909         unsigned char buf[4096];
 910         int len;
 911
 912         if (query == NULL)
 913                 return -ENOMEM;
 914
 915         len = res_mkquery(ns_o_query, hostname, ns_c_in, type,
 916                                         NULL, 0, NULL, buf, sizeof(buf));
 917
 918         query->msgid = buf[0] << 8 | buf[1];
 919
 920         if (send_query(lookup->resolv, buf, len) < 0) {
 921                 g_free(query);
 922                 return -EIO;
 923         }
 924
 925         query->resolv = lookup->resolv;
 926         query->lookup = lookup;
 927
 928         g_queue_push_tail(lookup->resolv->query_queue, query);
 929
 930         query->timeout = g_timeout_add_seconds(5, query_timeout, query);
 931
 932         if (type == ns_t_aaaa)
 933                 lookup->ipv6_query = query;
 934         else
 935                 lookup->ipv4_query = query;
 936
 937         return 0;
 938 }
 939
 940 guint g_resolv_lookup_hostname(GResolv *resolv, const char *hostname,
 941                                 GResolvResultFunc func, gpointer user_data)
 942 {
 943         struct resolv_lookup *lookup;
 944
 945         debug(resolv, "lookup hostname %s", hostname);
 946
 947         if (resolv == NULL)
 948                 return 0;
 949
 950         if (resolv->nameserver_list == NULL) {
 951                 int i;
 952
 953                 for (i = 0; i < resolv->res.nscount; i++) {
 954                         char buf[100];
 955                         int family = resolv->res.nsaddr_list[i].sin_family;
 956                         void *sa_addr = &resolv->res.nsaddr_list[i].sin_addr;
 957
 958                         if (family != AF_INET &&
 959                                         resolv->res._u._ext.nsaddrs[i]) {
 960                                 family = AF_INET6;
 961                                 sa_addr = &resolv->res._u._ext.nsaddrs[i]->sin6_addr;
 962                         }
 963
 964                         if (family != AF_INET && family != AF_INET6)
 965                                 continue;
 966
 967                         if (inet_ntop(family, sa_addr, buf, sizeof(buf)))
 968                                 g_resolv_add_nameserver(resolv, buf, 53, 0);
 969                 }
 970
 971                 if (resolv->nameserver_list == NULL)
 972                         g_resolv_add_nameserver(resolv, "127.0.0.1", 53, 0);
 973         }
 974
 975         lookup = g_try_new0(struct resolv_lookup, 1);
 976         if (lookup == NULL)
 977                 return 0;
 978
 979         lookup->resolv = resolv;
 980         lookup->result_func = func;
 981         lookup->result_data = user_data;
 982         lookup->id = resolv->next_lookup_id++;
 983
 984         if (resolv->result_family != AF_INET6) {
 985                 if (add_query(lookup, hostname, ns_t_a)) {
 986                         g_free(lookup);
 987                         return -EIO;
 988                 }
 989         }
 990
 991         if (resolv->result_family != AF_INET) {
 992                 if (add_query(lookup, hostname, ns_t_aaaa)) {
 993                         if (resolv->result_family != AF_INET6) {
 994                                 destroy_query(lookup->ipv4_query);
 995                                 g_queue_remove(resolv->query_queue,
 996                                                 lookup->ipv4_query);
 997                         }
 998
 999                         g_free(lookup);
1000                         return -EIO;
1001                 }
1002         }
1003
1004         g_queue_push_tail(resolv->lookup_queue, lookup);
1005         return lookup->id;
1006 }
1007
1008 gboolean g_resolv_cancel_lookup(GResolv *resolv, guint id)
1009 {
1010         GList *list;
1011
1012         list = g_queue_find_custom(resolv->lookup_queue,
1013                                 GUINT_TO_POINTER(id), compare_lookup_id);
1014
1015         if (list == NULL)
1016                 return FALSE;
1017
1018         destroy_lookup(list->data);
1019         g_queue_remove(resolv->query_queue, list->data);
1020
1021         return TRUE;
1022 }
1023
1024 gboolean g_resolv_set_address_family(GResolv *resolv, int family)
1025 {
1026         if (resolv == NULL)
1027                 return FALSE;
1028
1029         if (family != AF_UNSPEC && family != AF_INET && family != AF_INET6)
1030                 return FALSE;
1031
1032         resolv->result_family = family;
1033
1034         return TRUE;
1035 }