gweb/gresolv.c

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