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         int i, n = 0;
 475
 476         if (!results)
 477                 return;
 478
 479         memset(buf, 0, INET6_ADDRSTRLEN + 1);
 480
 481         rfc3484_sort_results(lookup);
 482
 483         for (i = 0; i < lookup->nr_results; i++) {
 484                 if (lookup->results[i].dst.sa.sa_family == AF_INET) {
 485                         if (inet_ntop(AF_INET,
 486                                         &lookup->results[i].dst.sin.sin_addr,
 487                                         buf, sizeof(buf) - 1) == NULL)
 488                                 continue;
 489                 } else if (lookup->results[i].dst.sa.sa_family == AF_INET6) {
 490                         if (inet_ntop(AF_INET6,
 491                                         &lookup->results[i].dst.sin6.sin6_addr,
 492                                         buf, sizeof(buf) - 1) == NULL)
 493                                 continue;
 494                 } else
 495                         continue;
 496
 497                 results[n++] = g_strdup(buf);
 498         }
 499
 500         results[n++] = NULL;
 501
 502         if (lookup->resolv->result_family == AF_INET)
 503                 status = lookup->ipv4_status;
 504         else if (lookup->resolv->result_family == AF_INET6)
 505                 status = lookup->ipv6_status;
 506         else {
 507                 if (lookup->ipv6_status == G_RESOLV_RESULT_STATUS_SUCCESS)
 508                         status = lookup->ipv6_status;
 509                 else
 510                         status = lookup->ipv4_status;
 511         }
 512
 513         debug(lookup->resolv, "lookup %p received %d results", lookup, n);
 514
 515         g_queue_remove(lookup->resolv->lookup_queue, lookup);
 516
 517         lookup->result_func(status, results, lookup->result_data);
 518
 519         g_strfreev(results);
 520         destroy_lookup(lookup);
 521 }
 522
 523 static gboolean query_timeout(gpointer user_data)
 524 {
 525         struct resolv_query *query = user_data;
 526         struct resolv_lookup *lookup = query->lookup;
 527         GResolv *resolv = query->resolv;
 528
 529         query->timeout = 0;
 530
 531         if (query == lookup->ipv4_query) {
 532                 lookup->ipv4_status = G_RESOLV_RESULT_STATUS_NO_RESPONSE;
 533                 lookup->ipv4_query = NULL;
 534         } else if (query == lookup->ipv6_query) {
 535                 lookup->ipv6_status = G_RESOLV_RESULT_STATUS_NO_RESPONSE;
 536                 lookup->ipv6_query = NULL;
 537         }
 538
 539         g_queue_remove(resolv->query_queue, query);
 540
 541         if (lookup->ipv4_query == NULL && lookup->ipv6_query == NULL)
 542                 sort_and_return_results(lookup);
 543
 544         destroy_query(query);
 545
 546         return FALSE;
 547 }
 548
 549 static void free_nameserver(struct resolv_nameserver *nameserver)
 550 {
 551         if (nameserver == NULL)
 552                 return;
 553
 554         if (nameserver->udp_watch > 0)
 555                 g_source_remove(nameserver->udp_watch);
 556
 557         if (nameserver->udp_channel != NULL) {
 558                 g_io_channel_shutdown(nameserver->udp_channel, TRUE, NULL);
 559                 g_io_channel_unref(nameserver->udp_channel);
 560         }
 561
 562         g_free(nameserver->address);
 563         g_free(nameserver);
 564 }
 565
 566 static void flush_nameservers(GResolv *resolv)
 567 {
 568         GList *list;
 569
 570         for (list = g_list_first(resolv->nameserver_list);
 571                                         list; list = g_list_next(list))
 572                 free_nameserver(list->data);
 573
 574         g_list_free(resolv->nameserver_list);
 575         resolv->nameserver_list = NULL;
 576 }
 577
 578 static int send_query(GResolv *resolv, const unsigned char *buf, int len)
 579 {
 580         GList *list;
 581
 582         if (resolv->nameserver_list == NULL)
 583                 return -ENOENT;
 584
 585         for (list = g_list_first(resolv->nameserver_list);
 586                                         list; list = g_list_next(list)) {
 587                 struct resolv_nameserver *nameserver = list->data;
 588                 int sk, sent;
 589
 590                 if (nameserver->udp_channel == NULL)
 591                         continue;
 592
 593                 sk = g_io_channel_unix_get_fd(nameserver->udp_channel);
 594
 595                 sent = send(sk, buf, len, 0);
 596                 if (sent < 0)
 597                         continue;
 598         }
 599
 600         return 0;
 601 }
 602
 603 static gint compare_lookup_id(gconstpointer a, gconstpointer b)
 604 {
 605         const struct resolv_lookup *lookup = a;
 606         guint id = GPOINTER_TO_UINT(b);
 607
 608         if (lookup->id < id)
 609                 return -1;
 610
 611         if (lookup->id > id)
 612                 return 1;
 613
 614         return 0;
 615 }
 616
 617 static gint compare_query_msgid(gconstpointer a, gconstpointer b)
 618 {
 619         const struct resolv_query *query = a;
 620         uint16_t msgid = GPOINTER_TO_UINT(b);
 621
 622         if (query->msgid < msgid)
 623                 return -1;
 624
 625         if (query->msgid > msgid)
 626                 return 1;
 627
 628         return 0;
 629 }
 630
 631 static void add_result(struct resolv_lookup *lookup, int family,
 632                                                         const void *data)
 633 {
 634         int n = lookup->nr_results++;
 635         lookup->results = g_try_realloc(lookup->results,
 636                                         sizeof(struct sort_result) * (n + 1));
 637         if (lookup->results == NULL)
 638                 return;
 639
 640         memset(&lookup->results[n], 0, sizeof(struct sort_result));
 641
 642         lookup->results[n].dst.sa.sa_family = family;
 643         if (family == AF_INET)
 644                 memcpy(&lookup->results[n].dst.sin.sin_addr,
 645                                                 data, NS_INADDRSZ);
 646         else
 647                 memcpy(&lookup->results[n].dst.sin6.sin6_addr,
 648                                                 data, NS_IN6ADDRSZ);
 649 }
 650
 651 static void parse_response(struct resolv_nameserver *nameserver,
 652                                         const unsigned char *buf, int len)
 653 {
 654         GResolv *resolv = nameserver->resolv;
 655         GResolvResultStatus status;
 656         struct resolv_query *query;
 657         struct resolv_lookup *lookup;
 658         GList *list;
 659         ns_msg msg;
 660         ns_rr rr;
 661         int i, rcode, count;
 662
 663         debug(resolv, "response from %s", nameserver->address);
 664
 665         ns_initparse(buf, len, &msg);
 666
 667         rcode = ns_msg_getflag(msg, ns_f_rcode);
 668         count = ns_msg_count(msg, ns_s_an);
 669
 670         debug(resolv, "msg id: 0x%04x rcode: %d count: %d",
 671                                         ns_msg_id(msg), rcode, count);
 672
 673         switch (rcode) {
 674         case ns_r_noerror:
 675                 status = G_RESOLV_RESULT_STATUS_SUCCESS;
 676                 break;
 677         case ns_r_formerr:
 678                 status = G_RESOLV_RESULT_STATUS_FORMAT_ERROR;
 679                 break;
 680         case ns_r_servfail:
 681                 status = G_RESOLV_RESULT_STATUS_SERVER_FAILURE;
 682                 break;
 683         case ns_r_nxdomain:
 684                 status = G_RESOLV_RESULT_STATUS_NAME_ERROR;
 685                 break;
 686         case ns_r_notimpl:
 687                 status = G_RESOLV_RESULT_STATUS_NOT_IMPLEMENTED;
 688                 break;
 689         case ns_r_refused:
 690                 status = G_RESOLV_RESULT_STATUS_REFUSED;
 691                 break;
 692         default:
 693                 status = G_RESOLV_RESULT_STATUS_ERROR;
 694                 break;
 695         }
 696
 697         list = g_queue_find_custom(resolv->query_queue,
 698                         GUINT_TO_POINTER(ns_msg_id(msg)), compare_query_msgid);
 699         if (!list)
 700                 return;
 701
 702         query = list->data;
 703         lookup = query->lookup;
 704
 705         if (query == lookup->ipv6_query) {
 706                 lookup->ipv6_status = status;
 707                 lookup->ipv6_query = NULL;
 708         } else if (query == lookup->ipv4_query) {
 709                 lookup->ipv4_status = status;
 710                 lookup->ipv4_query = NULL;
 711         }
 712
 713         for (i = 0; i < count; i++) {
 714                 ns_parserr(&msg, ns_s_an, i, &rr);
 715
 716                 if (ns_rr_class(rr) != ns_c_in)
 717                         continue;
 718
 719                 g_assert(offsetof(struct sockaddr_in, sin_addr) ==
 720                                 offsetof(struct sockaddr_in6, sin6_flowinfo));
 721
 722                 if (ns_rr_type(rr) == ns_t_a &&
 723                                         ns_rr_rdlen(rr) == NS_INADDRSZ) {
 724                         add_result(lookup, AF_INET, ns_rr_rdata(rr));
 725                 } else if (ns_rr_type(rr) == ns_t_aaaa &&
 726                                         ns_rr_rdlen(rr) == NS_IN6ADDRSZ) {
 727                         add_result(lookup, AF_INET6, ns_rr_rdata(rr));
 728                 }
 729         }
 730
 731         g_queue_remove(resolv->query_queue, query);
 732
 733         if (lookup->ipv4_query == NULL && lookup->ipv6_query == NULL)
 734                 sort_and_return_results(lookup);
 735
 736         destroy_query(query);
 737 }
 738
 739 static gboolean received_udp_data(GIOChannel *channel, GIOCondition cond,
 740                                                         gpointer user_data)
 741 {
 742         struct resolv_nameserver *nameserver = user_data;
 743         unsigned char buf[4096];
 744         int sk, len;
 745
 746         if (cond & (G_IO_NVAL | G_IO_ERR | G_IO_HUP)) {
 747                 nameserver->udp_watch = 0;
 748                 return FALSE;
 749         }
 750
 751         sk = g_io_channel_unix_get_fd(nameserver->udp_channel);
 752
 753         len = recv(sk, buf, sizeof(buf), 0);
 754         if (len < 12)
 755                 return TRUE;
 756
 757         parse_response(nameserver, buf, len);
 758
 759         return TRUE;
 760 }
 761
 762 static int connect_udp_channel(struct resolv_nameserver *nameserver)
 763 {
 764         struct addrinfo hints, *rp;
 765         char portnr[6];
 766         int err, sk;
 767
 768         memset(&hints, 0, sizeof(hints));
 769         hints.ai_family = AF_UNSPEC;
 770         hints.ai_socktype = SOCK_DGRAM;
 771         hints.ai_flags = AI_PASSIVE | AI_NUMERICSERV | AI_NUMERICHOST;
 772
 773         sprintf(portnr, "%d", nameserver->port);
 774         err = getaddrinfo(nameserver->address, portnr, &hints, &rp);
 775         if (err)
 776                 return -EINVAL;
 777
 778         /*
 779          * Do not blindly copy this code elsewhere; it doesn't loop over the
 780          * results using ->ai_next as it should. That's OK in *this* case
 781          * because it was a numeric lookup; we *know* there's only one.
 782          */
 783         if (!rp)
 784                 return -EINVAL;
 785
 786         sk = socket(rp->ai_family, rp->ai_socktype, rp->ai_protocol);
 787         if (sk < 0) {
 788                 freeaddrinfo(rp);
 789                 return -EIO;
 790         }
 791
 792         /*
 793          * If nameserver points to localhost ip, their is no need to
 794          * bind the socket on any interface.
 795          */
 796         if (nameserver->resolv->index > 0 &&
 797                         strncmp(nameserver->address, "127.0.0.1", 9) != 0) {
 798                 char interface[IF_NAMESIZE];
 799
 800                 memset(interface, 0, IF_NAMESIZE);
 801                 if (if_indextoname(nameserver->resolv->index,
 802                                                 interface) != NULL) {
 803                         if (setsockopt(sk, SOL_SOCKET, SO_BINDTODEVICE,
 804                                                 interface, IF_NAMESIZE) < 0) {
 805                                 close(sk);
 806                                 freeaddrinfo(rp);
 807                                 return -EIO;
 808                         }
 809                 }
 810         }
 811
 812         if (connect(sk, rp->ai_addr, rp->ai_addrlen) < 0) {
 813                 close(sk);
 814                 freeaddrinfo(rp);
 815                 return -EIO;
 816         }
 817
 818         freeaddrinfo(rp);
 819
 820         nameserver->udp_channel = g_io_channel_unix_new(sk);
 821         if (nameserver->udp_channel == NULL) {
 822                 close(sk);
 823                 return -ENOMEM;
 824         }
 825
 826         g_io_channel_set_close_on_unref(nameserver->udp_channel, TRUE);
 827
 828         nameserver->udp_watch = g_io_add_watch(nameserver->udp_channel,
 829                                 G_IO_IN | G_IO_NVAL | G_IO_ERR | G_IO_HUP,
 830                                 received_udp_data, nameserver);
 831
 832         return 0;
 833 }
 834
 835 GResolv *g_resolv_new(int index)
 836 {
 837         GResolv *resolv;
 838
 839         if (index < 0)
 840                 return NULL;
 841
 842         resolv = g_try_new0(GResolv, 1);
 843         if (resolv == NULL)
 844                 return NULL;
 845
 846         resolv->ref_count = 1;
 847
 848         resolv->result_family = AF_UNSPEC;
 849
 850         resolv->next_lookup_id = 1;
 851
 852         resolv->query_queue = g_queue_new();
 853         if (resolv->query_queue == NULL) {
 854                 g_free(resolv);
 855                 return NULL;
 856         }
 857
 858         resolv->lookup_queue = g_queue_new();
 859         if (resolv->lookup_queue == NULL) {
 860                 g_queue_free(resolv->query_queue);
 861                 g_free(resolv);
 862                 return NULL;
 863         }
 864
 865         resolv->index = index;
 866         resolv->nameserver_list = NULL;
 867
 868         res_ninit(&resolv->res);
 869
 870         return resolv;
 871 }
 872
 873 GResolv *g_resolv_ref(GResolv *resolv)
 874 {
 875         if (resolv == NULL)
 876                 return NULL;
 877
 878         __sync_fetch_and_add(&resolv->ref_count, 1);
 879
 880         return resolv;
 881 }
 882
 883 void g_resolv_unref(GResolv *resolv)
 884 {
 885         struct resolv_query *query;
 886         struct resolv_lookup *lookup;
 887
 888         if (resolv == NULL)
 889                 return;
 890
 891         if (__sync_fetch_and_sub(&resolv->ref_count, 1) != 1)
 892                 return;
 893
 894         while ((lookup = g_queue_pop_head(resolv->lookup_queue))) {
 895                 debug(resolv, "lookup %p id %d", lookup, lookup->id);
 896                 destroy_lookup(lookup);
 897         }
 898
 899         while ((query = g_queue_pop_head(resolv->query_queue))) {
 900                 debug(resolv, "query %p", query);
 901                 destroy_query(query);
 902         }
 903
 904         g_queue_free(resolv->query_queue);
 905         g_queue_free(resolv->lookup_queue);
 906
 907         flush_nameservers(resolv);
 908
 909         res_nclose(&resolv->res);
 910
 911         g_free(resolv);
 912 }
 913
 914 void g_resolv_set_debug(GResolv *resolv, GResolvDebugFunc func,
 915                                                 gpointer user_data)
 916 {
 917         if (resolv == NULL)
 918                 return;
 919
 920         resolv->debug_func = func;
 921         resolv->debug_data = user_data;
 922 }
 923
 924 gboolean g_resolv_add_nameserver(GResolv *resolv, const char *address,
 925                                         uint16_t port, unsigned long flags)
 926 {
 927         struct resolv_nameserver *nameserver;
 928
 929         if (resolv == NULL)
 930                 return FALSE;
 931
 932         nameserver = g_try_new0(struct resolv_nameserver, 1);
 933         if (nameserver == NULL)
 934                 return FALSE;
 935
 936         nameserver->address = g_strdup(address);
 937         nameserver->port = port;
 938         nameserver->flags = flags;
 939         nameserver->resolv = resolv;
 940
 941         if (connect_udp_channel(nameserver) < 0) {
 942                 free_nameserver(nameserver);
 943                 return FALSE;
 944         }
 945
 946         resolv->nameserver_list = g_list_append(resolv->nameserver_list,
 947                                                                 nameserver);
 948
 949         debug(resolv, "setting nameserver %s", address);
 950
 951         return TRUE;
 952 }
 953
 954 void g_resolv_flush_nameservers(GResolv *resolv)
 955 {
 956         if (resolv == NULL)
 957                 return;
 958
 959         flush_nameservers(resolv);
 960 }
 961
 962 static gint add_query(struct resolv_lookup *lookup, const char *hostname, int type)
 963 {
 964         struct resolv_query *query = g_try_new0(struct resolv_query, 1);
 965         unsigned char buf[4096];
 966         int len;
 967
 968         if (query == NULL)
 969                 return -ENOMEM;
 970
 971         len = res_mkquery(ns_o_query, hostname, ns_c_in, type,
 972                                         NULL, 0, NULL, buf, sizeof(buf));
 973
 974         query->msgid = buf[0] << 8 | buf[1];
 975
 976         debug(lookup->resolv, "sending %d bytes", len);
 977
 978         if (send_query(lookup->resolv, buf, len) < 0) {
 979                 g_free(query);
 980                 return -EIO;
 981         }
 982
 983         query->resolv = lookup->resolv;
 984         query->lookup = lookup;
 985
 986         g_queue_push_tail(lookup->resolv->query_queue, query);
 987
 988         debug(lookup->resolv, "lookup %p id %d query %p", lookup, lookup->id,
 989                                                                         query);
 990
 991         query->timeout = g_timeout_add_seconds(5, query_timeout, query);
 992
 993         if (type == ns_t_aaaa)
 994                 lookup->ipv6_query = query;
 995         else
 996                 lookup->ipv4_query = query;
 997
 998         return 0;
 999 }
1000
1001 guint g_resolv_lookup_hostname(GResolv *resolv, const char *hostname,
1002                                 GResolvResultFunc func, gpointer user_data)
1003 {
1004         struct resolv_lookup *lookup;
1005
1006         if (resolv == NULL)
1007                 return 0;
1008
1009         debug(resolv, "hostname %s", hostname);
1010
1011         if (resolv->nameserver_list == NULL) {
1012                 int i;
1013
1014                 for (i = 0; i < resolv->res.nscount; i++) {
1015                         char buf[100];
1016                         int family = resolv->res.nsaddr_list[i].sin_family;
1017                         void *sa_addr = &resolv->res.nsaddr_list[i].sin_addr;
1018
1019                         if (family != AF_INET &&
1020                                         resolv->res._u._ext.nsaddrs[i]) {
1021                                 family = AF_INET6;
1022                                 sa_addr = &resolv->res._u._ext.nsaddrs[i]->sin6_addr;
1023                         }
1024
1025                         if (family != AF_INET && family != AF_INET6)
1026                                 continue;
1027
1028                         if (inet_ntop(family, sa_addr, buf, sizeof(buf)))
1029                                 g_resolv_add_nameserver(resolv, buf, 53, 0);
1030                 }
1031
1032                 if (resolv->nameserver_list == NULL)
1033                         g_resolv_add_nameserver(resolv, "127.0.0.1", 53, 0);
1034         }
1035
1036         lookup = g_try_new0(struct resolv_lookup, 1);
1037         if (lookup == NULL)
1038                 return 0;
1039
1040         lookup->resolv = resolv;
1041         lookup->result_func = func;
1042         lookup->result_data = user_data;
1043         lookup->id = resolv->next_lookup_id++;
1044
1045         if (resolv->result_family != AF_INET6) {
1046                 if (add_query(lookup, hostname, ns_t_a)) {
1047                         g_free(lookup);
1048                         return -EIO;
1049                 }
1050         }
1051
1052         if (resolv->result_family != AF_INET) {
1053                 if (add_query(lookup, hostname, ns_t_aaaa)) {
1054                         if (resolv->result_family != AF_INET6) {
1055                                 g_queue_remove(resolv->query_queue,
1056                                                 lookup->ipv4_query);
1057                                 destroy_query(lookup->ipv4_query);
1058                         }
1059
1060                         g_free(lookup);
1061                         return -EIO;
1062                 }
1063         }
1064
1065         g_queue_push_tail(resolv->lookup_queue, lookup);
1066
1067         debug(resolv, "lookup %p id %d", lookup, lookup->id);
1068
1069         return lookup->id;
1070 }
1071
1072 gboolean g_resolv_cancel_lookup(GResolv *resolv, guint id)
1073 {
1074         struct resolv_lookup *lookup;
1075         GList *list;
1076
1077         debug(resolv, "lookup id %d", id);
1078
1079         list = g_queue_find_custom(resolv->lookup_queue,
1080                                 GUINT_TO_POINTER(id), compare_lookup_id);
1081
1082         if (list == NULL)
1083                 return FALSE;
1084
1085         lookup = list->data;
1086
1087         debug(resolv, "lookup %p", lookup);
1088
1089         g_queue_remove(resolv->lookup_queue, lookup);
1090         destroy_lookup(lookup);
1091
1092         return TRUE;
1093 }
1094
1095 gboolean g_resolv_set_address_family(GResolv *resolv, int family)
1096 {
1097         if (resolv == NULL)
1098                 return FALSE;
1099
1100         if (family != AF_UNSPEC && family != AF_INET && family != AF_INET6)
1101                 return FALSE;
1102
1103         resolv->result_family = family;
1104
1105         return TRUE;
1106 }