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 <stdio.h>
  32 #include <resolv.h>
  33 #include <sys/types.h>
  34 #include <sys/socket.h>
  35 #include <netdb.h>
  36 #include <arpa/inet.h>
  37 #include <arpa/nameser.h>
  38 #include <net/if.h>
  39
  40 #include "gresolv.h"
  41
  42 struct sort_result {
  43         int precedence;
  44         int src_scope;
  45         int dst_scope;
  46         int src_label;
  47         int dst_label;
  48         bool reachable;
  49         union {
  50                 struct sockaddr sa;
  51                 struct sockaddr_in sin;
  52                 struct sockaddr_in6 sin6;
  53         } src;
  54         union {
  55                 struct sockaddr sa;
  56                 struct sockaddr_in sin;
  57                 struct sockaddr_in6 sin6;
  58         } dst;
  59 };
  60
  61 struct resolv_query;
  62
  63 struct resolv_lookup {
  64         GResolv *resolv;
  65         guint id;
  66
  67         int nr_results;
  68         struct sort_result *results;
  69
  70         struct resolv_query *ipv4_query;
  71         struct resolv_query *ipv6_query;
  72
  73         guint ipv4_status;
  74         guint ipv6_status;
  75
  76         GResolvResultFunc result_func;
  77         gpointer result_data;
  78 };
  79
  80 struct resolv_query {
  81         GResolv *resolv;
  82
  83         int nr_ns;
  84         guint timeout;
  85
  86         uint16_t msgid;
  87
  88         struct resolv_lookup *lookup;
  89 };
  90
  91 struct resolv_nameserver {
  92         GResolv *resolv;
  93
  94         char *address;
  95         uint16_t port;
  96         unsigned long flags;
  97
  98         GIOChannel *udp_channel;
  99         guint udp_watch;
 100 };
 101
 102 struct _GResolv {
 103         int ref_count;
 104
 105         int result_family;
 106
 107         guint next_lookup_id;
 108         GQueue *lookup_queue;
 109         GQueue *query_queue;
 110
 111         int index;
 112         GList *nameserver_list;
 113
 114         struct __res_state res;
 115
 116         GResolvDebugFunc debug_func;
 117         gpointer debug_data;
 118 };
 119
 120 #define debug(resolv, format, arg...)                           \
 121         _debug(resolv, __FILE__, __func__, format, ## arg)
 122
 123 static void _debug(GResolv *resolv, const char *file, const char *caller,
 124                                                 const char *format, ...)
 125 {
 126         char str[256];
 127         va_list ap;
 128         int len;
 129
 130         if (!resolv->debug_func)
 131                 return;
 132
 133         va_start(ap, format);
 134
 135         if ((len = snprintf(str, sizeof(str), "%s:%s() resolv %p ",
 136                                                 file, caller, resolv)) > 0) {
 137                 if (vsnprintf(str + len, sizeof(str) - len, format, ap) > 0)
 138                         resolv->debug_func(str, resolv->debug_data);
 139         }
 140
 141         va_end(ap);
 142 }
 143
 144 static void destroy_query(struct resolv_query *query)
 145 {
 146         debug(query->resolv, "query %p timeout %d", query, query->timeout);
 147
 148         if (query->timeout > 0)
 149                 g_source_remove(query->timeout);
 150
 151         g_free(query);
 152 }
 153
 154 static void destroy_lookup(struct resolv_lookup *lookup)
 155 {
 156         debug(lookup->resolv, "lookup %p id %d ipv4 %p ipv6 %p",
 157                 lookup, lookup->id, lookup->ipv4_query, lookup->ipv6_query);
 158
 159         if (lookup->ipv4_query) {
 160                 g_queue_remove(lookup->resolv->query_queue,
 161                                                 lookup->ipv4_query);
 162                 destroy_query(lookup->ipv4_query);
 163         }
 164
 165         if (lookup->ipv6_query) {
 166                 g_queue_remove(lookup->resolv->query_queue,
 167                                                 lookup->ipv6_query);
 168                 destroy_query(lookup->ipv6_query);
 169         }
 170
 171         g_free(lookup->results);
 172         g_free(lookup);
 173 }
 174
 175 static void find_srcaddr(struct sort_result *res)
 176 {
 177         socklen_t sl = sizeof(res->src);
 178         int fd;
 179
 180         fd = socket(res->dst.sa.sa_family, SOCK_DGRAM | SOCK_CLOEXEC,
 181                         IPPROTO_IP);
 182         if (fd < 0)
 183                 return;
 184
 185         if (connect(fd, &res->dst.sa, sizeof(res->dst)) < 0)
 186                 goto out;
 187
 188         if (getsockname(fd, &res->src.sa, &sl) < 0)
 189                 goto out;
 190
 191         res->reachable = true;
 192
 193 out:
 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 bool 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) ( (((uint32_t)_a)<<24) | (((uint32_t)_b)<<16) | \
 319                                 (((uint32_t)_c)<<8) | ((uint32_t)_d) )
 320 #define V4MATCH(addr, a,b,c,d, m) ( ((addr) ^ DQUAD(a,b,c,d)) >> (32 - (m)) )
 321
 322 #define RFC3484_SCOPE_LINK      2
 323 #define RFC3484_SCOPE_SITE      5
 324 #define RFC3484_SCOPE_GLOBAL    14
 325
 326 static int addr_scope(struct sockaddr *sa)
 327 {
 328         if (sa->sa_family == AF_INET) {
 329                 struct sockaddr_in *sin = (void *)sa;
 330                 uint32_t addr = ntohl(sin->sin_addr.s_addr);
 331
 332                 if (V4MATCH(addr, 169,254,0,0, 16) ||
 333                                         V4MATCH(addr, 127,0,0,0, 8))
 334                         return RFC3484_SCOPE_LINK;
 335
 336                 /* Site-local */
 337                 if (V4MATCH(addr, 10,0,0,0, 8) ||
 338                                 V4MATCH(addr, 172,16,0,0, 12) ||
 339                                 V4MATCH(addr, 192,168,0,0, 16))
 340                         return RFC3484_SCOPE_SITE;
 341
 342                 /* Global */
 343                 return RFC3484_SCOPE_GLOBAL;
 344         } else {
 345                 struct sockaddr_in6 *sin6 = (void *)sa;
 346
 347                 /* Multicast addresses have a 4-bit scope field */
 348                 if (IN6_IS_ADDR_MULTICAST(&sin6->sin6_addr))
 349                         return sin6->sin6_addr.s6_addr[1] & 0xf;
 350
 351                 if (IN6_IS_ADDR_LINKLOCAL(&sin6->sin6_addr) ||
 352                                 IN6_IS_ADDR_LOOPBACK(&sin6->sin6_addr))
 353                         return RFC3484_SCOPE_LINK;
 354
 355                 if (IN6_IS_ADDR_SITELOCAL(&sin6->sin6_addr))
 356                         return RFC3484_SCOPE_SITE;
 357
 358                 return RFC3484_SCOPE_GLOBAL;
 359         }
 360 }
 361
 362 static int rfc3484_compare(const void *__one, const void *__two)
 363 {
 364         const struct sort_result *one = __one;
 365         const struct sort_result *two = __two;
 366
 367         /* Rule 1: Avoid unusable destinations */
 368         if (one->reachable && !two->reachable)
 369                 return -1;
 370         else if (two->reachable && !one->reachable)
 371                 return 1;
 372
 373         /* Rule 2: Prefer matching scope */
 374         if (one->dst_scope == one->src_scope &&
 375                                 two->dst_scope != two->src_scope)
 376                 return -1;
 377         else if (two->dst_scope == two->src_scope &&
 378                                 one->dst_scope != one->src_scope)
 379                 return 1;
 380
 381         /* Rule 3: Avoid deprecated addresses */
 382
 383         /* Rule 4: Prefer home addresses */
 384
 385         /* Rule 5: Prefer matching label */
 386         if (one->dst_label == one->src_label &&
 387                                 two->dst_label != two->src_label)
 388                 return -1;
 389         else if (two->dst_label == two->src_label &&
 390                                 one->dst_label != one->src_label)
 391                 return 1;
 392
 393         /* Rule 6: Prefer higher precedence */
 394         if (one->precedence > two->precedence)
 395                 return -1;
 396         else if (two->precedence > one->precedence)
 397                 return 1;
 398
 399         /* Rule 7: Prefer native transport */
 400
 401         /* Rule 8: Prefer smaller scope */
 402         if (one->dst_scope != two->dst_scope)
 403                 return one->dst_scope - two->dst_scope;
 404
 405         /* Rule 9: Use longest matching prefix */
 406         if (one->dst.sa.sa_family == AF_INET) {
 407                 /*
 408                  * Rule 9 is meaningless and counterproductive for Legacy IP
 409                  * unless perhaps we can tell that it's actually on the local
 410                  * subnet. But we don't (yet) have local interface config
 411                  * information, so do nothing here for Legacy IP for now.
 412                  */
 413         } else {
 414                 int i;
 415
 416                 for (i = 0; i < 4; i++) {
 417                         guint32 cmp_one, cmp_two;
 418
 419                         cmp_one = one->src.sin6.sin6_addr.s6_addr32[i] ^
 420                                         one->dst.sin6.sin6_addr.s6_addr32[i];
 421                         cmp_two = two->src.sin6.sin6_addr.s6_addr32[i] ^
 422                                         two->dst.sin6.sin6_addr.s6_addr32[i];
 423
 424                         if (!cmp_two && !cmp_one)
 425                                 continue;
 426
 427                         if (cmp_one && !cmp_two)
 428                                 return 1;
 429                         if (cmp_two && !cmp_one)
 430                                 return -1;
 431
 432                         /* g_bit_storage() is effectively fls() */
 433                         cmp_one = g_bit_storage(ntohl(cmp_one));
 434                         cmp_two = g_bit_storage(ntohl(cmp_two));
 435
 436                         if (cmp_one == cmp_two)
 437                                 break;
 438
 439                         return cmp_one - cmp_two;
 440                 }
 441         }
 442
 443
 444         /* Rule 10: Otherwise, leave the order unchanged */
 445         if (one < two)
 446                 return -1;
 447         else
 448                 return 1;
 449 }
 450
 451 static void rfc3484_sort_results(struct resolv_lookup *lookup)
 452 {
 453         int i;
 454
 455         for (i = 0; i < lookup->nr_results; i++) {
 456                 struct sort_result *res = &lookup->results[i];
 457                 find_srcaddr(res);
 458                 res->precedence = match_gai_table(&res->dst.sa,
 459                                                         gai_precedences);
 460                 res->dst_label = match_gai_table(&res->dst.sa, gai_labels);
 461                 res->src_label = match_gai_table(&res->src.sa, gai_labels);
 462                 res->dst_scope = addr_scope(&res->dst.sa);
 463                 res->src_scope = addr_scope(&res->src.sa);
 464         }
 465
 466         qsort(lookup->results, lookup->nr_results,
 467                         sizeof(struct sort_result), rfc3484_compare);
 468 }
 469
 470 static void sort_and_return_results(struct resolv_lookup *lookup)
 471 {
 472         char buf[INET6_ADDRSTRLEN + 1];
 473         GResolvResultStatus status;
 474         char **results = g_try_new0(char *, lookup->nr_results + 1);
 475         GResolvResultFunc result_func = lookup->result_func;
 476         void *result_data = lookup->result_data;
 477         int i, n = 0;
 478
 479         if (!results)
 480                 return;
 481
 482         memset(buf, 0, INET6_ADDRSTRLEN + 1);
 483
 484         rfc3484_sort_results(lookup);
 485
 486         for (i = 0; i < lookup->nr_results; i++) {
 487                 if (lookup->results[i].dst.sa.sa_family == AF_INET) {
 488                         if (!inet_ntop(AF_INET,
 489                                         &lookup->results[i].dst.sin.sin_addr,
 490                                         buf, sizeof(buf) - 1))
 491                                 continue;
 492                 } else if (lookup->results[i].dst.sa.sa_family == AF_INET6) {
 493                         if (!inet_ntop(AF_INET6,
 494                                         &lookup->results[i].dst.sin6.sin6_addr,
 495                                         buf, sizeof(buf) - 1))
 496                                 continue;
 497                 } else
 498                         continue;
 499
 500                 results[n++] = g_strdup(buf);
 501         }
 502
 503         results[n++] = NULL;
 504
 505         if (lookup->resolv->result_family == AF_INET)
 506                 status = lookup->ipv4_status;
 507         else if (lookup->resolv->result_family == AF_INET6)
 508                 status = lookup->ipv6_status;
 509         else {
 510                 if (lookup->ipv6_status == G_RESOLV_RESULT_STATUS_SUCCESS)
 511                         status = lookup->ipv6_status;
 512                 else
 513                         status = lookup->ipv4_status;
 514         }
 515
 516         debug(lookup->resolv, "lookup %p received %d results", lookup, n-1);
 517
 518         g_queue_remove(lookup->resolv->lookup_queue, lookup);
 519         destroy_lookup(lookup);
 520
 521         result_func(status, results, result_data);
 522
 523         g_strfreev(results);
 524 }
 525
 526 static gboolean query_timeout(gpointer user_data)
 527 {
 528         struct resolv_query *query = user_data;
 529         struct resolv_lookup *lookup = query->lookup;
 530         GResolv *resolv = query->resolv;
 531
 532         query->timeout = 0;
 533
 534         if (query == lookup->ipv4_query) {
 535                 lookup->ipv4_status = G_RESOLV_RESULT_STATUS_NO_RESPONSE;
 536                 lookup->ipv4_query = NULL;
 537         } else if (query == lookup->ipv6_query) {
 538                 lookup->ipv6_status = G_RESOLV_RESULT_STATUS_NO_RESPONSE;
 539                 lookup->ipv6_query = NULL;
 540         }
 541
 542         g_queue_remove(resolv->query_queue, query);
 543         destroy_query(query);
 544
 545         if (!lookup->ipv4_query && !lookup->ipv6_query)
 546                 sort_and_return_results(lookup);
 547
 548         return FALSE;
 549 }
 550
 551 static void free_nameserver(struct resolv_nameserver *nameserver)
 552 {
 553         if (!nameserver)
 554                 return;
 555
 556         if (nameserver->udp_watch > 0)
 557                 g_source_remove(nameserver->udp_watch);
 558
 559         if (nameserver->udp_channel) {
 560                 g_io_channel_shutdown(nameserver->udp_channel, TRUE, NULL);
 561                 g_io_channel_unref(nameserver->udp_channel);
 562         }
 563
 564         g_free(nameserver->address);
 565         g_free(nameserver);
 566 }
 567
 568 static void flush_nameservers(GResolv *resolv)
 569 {
 570         GList *list;
 571
 572         for (list = g_list_first(resolv->nameserver_list);
 573                                         list; list = g_list_next(list))
 574                 free_nameserver(list->data);
 575
 576         g_list_free(resolv->nameserver_list);
 577         resolv->nameserver_list = NULL;
 578 }
 579
 580 static int send_query(GResolv *resolv, const unsigned char *buf, int len)
 581 {
 582         GList *list;
 583         int nr_ns;
 584
 585         if (!resolv->nameserver_list)
 586                 return -ENOENT;
 587
 588         for (list = g_list_first(resolv->nameserver_list), nr_ns = 0;
 589                                 list; list = g_list_next(list), nr_ns++) {
 590                 struct resolv_nameserver *nameserver = list->data;
 591                 int sk, sent;
 592
 593                 if (!nameserver->udp_channel)
 594                         continue;
 595
 596                 sk = g_io_channel_unix_get_fd(nameserver->udp_channel);
 597
 598                 sent = send(sk, buf, len, 0);
 599                 if (sent < 0)
 600                         continue;
 601         }
 602
 603         return nr_ns;
 604 }
 605
 606 static gint compare_lookup_id(gconstpointer a, gconstpointer b)
 607 {
 608         const struct resolv_lookup *lookup = a;
 609         guint id = GPOINTER_TO_UINT(b);
 610
 611         if (lookup->id < id)
 612                 return -1;
 613
 614         if (lookup->id > id)
 615                 return 1;
 616
 617         return 0;
 618 }
 619
 620 static gint compare_query_msgid(gconstpointer a, gconstpointer b)
 621 {
 622         const struct resolv_query *query = a;
 623         uint16_t msgid = GPOINTER_TO_UINT(b);
 624
 625         if (query->msgid < msgid)
 626                 return -1;
 627
 628         if (query->msgid > msgid)
 629                 return 1;
 630
 631         return 0;
 632 }
 633
 634 static void add_result(struct resolv_lookup *lookup, int family,
 635                                                         const void *data)
 636 {
 637         int n = lookup->nr_results++;
 638         lookup->results = g_try_realloc(lookup->results,
 639                                         sizeof(struct sort_result) * (n + 1));
 640         if (!lookup->results)
 641                 return;
 642
 643         memset(&lookup->results[n], 0, sizeof(struct sort_result));
 644
 645         lookup->results[n].dst.sa.sa_family = family;
 646         if (family == AF_INET)
 647                 memcpy(&lookup->results[n].dst.sin.sin_addr,
 648                                                 data, NS_INADDRSZ);
 649         else
 650                 memcpy(&lookup->results[n].dst.sin6.sin6_addr,
 651                                                 data, NS_IN6ADDRSZ);
 652 }
 653
 654 static void parse_response(struct resolv_nameserver *nameserver,
 655                                         const unsigned char *buf, int len)
 656 {
 657         GResolv *resolv = nameserver->resolv;
 658         GResolvResultStatus status;
 659         struct resolv_query *query;
 660         struct resolv_lookup *lookup;
 661         GList *list;
 662         ns_msg msg;
 663         ns_rr rr;
 664         int i, rcode, count;
 665
 666         debug(resolv, "response from %s", nameserver->address);
 667
 668         if (ns_initparse(buf, len, &msg) < 0)
 669                 return;
 670
 671         list = g_queue_find_custom(resolv->query_queue,
 672                         GUINT_TO_POINTER(ns_msg_id(msg)), compare_query_msgid);
 673         if (!list)
 674                 return;
 675
 676         rcode = ns_msg_getflag(msg, ns_f_rcode);
 677         count = ns_msg_count(msg, ns_s_an);
 678
 679         debug(resolv, "msg id: 0x%04x rcode: %d count: %d",
 680                                         ns_msg_id(msg), rcode, count);
 681
 682         switch (rcode) {
 683         case ns_r_noerror:
 684                 if (count > 0)
 685                         status = G_RESOLV_RESULT_STATUS_SUCCESS;
 686                 else
 687                         status = G_RESOLV_RESULT_STATUS_NO_ANSWER;
 688                 break;
 689         case ns_r_formerr:
 690                 status = G_RESOLV_RESULT_STATUS_FORMAT_ERROR;
 691                 break;
 692         case ns_r_servfail:
 693                 status = G_RESOLV_RESULT_STATUS_SERVER_FAILURE;
 694                 break;
 695         case ns_r_nxdomain:
 696                 status = G_RESOLV_RESULT_STATUS_NAME_ERROR;
 697                 break;
 698         case ns_r_notimpl:
 699                 status = G_RESOLV_RESULT_STATUS_NOT_IMPLEMENTED;
 700                 break;
 701         case ns_r_refused:
 702                 status = G_RESOLV_RESULT_STATUS_REFUSED;
 703                 break;
 704         default:
 705                 status = G_RESOLV_RESULT_STATUS_ERROR;
 706                 break;
 707         }
 708
 709         query = list->data;
 710         query->nr_ns--;
 711
 712         lookup = query->lookup;
 713
 714         if (query == lookup->ipv6_query)
 715                 lookup->ipv6_status = status;
 716         else if (query == lookup->ipv4_query)
 717                 lookup->ipv4_status = status;
 718
 719         for (i = 0; i < count; i++) {
 720                 if (ns_parserr(&msg, ns_s_an, i, &rr) < 0)
 721                         continue;
 722
 723                 if (ns_rr_class(rr) != ns_c_in)
 724                         continue;
 725
 726                 g_assert(offsetof(struct sockaddr_in, sin_addr) ==
 727                                 offsetof(struct sockaddr_in6, sin6_flowinfo));
 728
 729                 if (ns_rr_type(rr) == ns_t_a &&
 730                                         ns_rr_rdlen(rr) == NS_INADDRSZ) {
 731                         add_result(lookup, AF_INET, ns_rr_rdata(rr));
 732                 } else if (ns_rr_type(rr) == ns_t_aaaa &&
 733                                         ns_rr_rdlen(rr) == NS_IN6ADDRSZ) {
 734                         add_result(lookup, AF_INET6, ns_rr_rdata(rr));
 735                 }
 736         }
 737
 738         if (status != G_RESOLV_RESULT_STATUS_SUCCESS && query->nr_ns > 0)
 739                 return;
 740
 741         if (query == lookup->ipv6_query)
 742                 lookup->ipv6_query = NULL;
 743         else
 744                 lookup->ipv4_query = NULL;
 745
 746         g_queue_remove(resolv->query_queue, query);
 747         destroy_query(query);
 748
 749         if (!lookup->ipv4_query && !lookup->ipv6_query)
 750                 sort_and_return_results(lookup);
 751 }
 752
 753 static gboolean received_udp_data(GIOChannel *channel, GIOCondition cond,
 754                                                         gpointer user_data)
 755 {
 756         struct resolv_nameserver *nameserver = user_data;
 757         unsigned char buf[4096];
 758         int sk, len;
 759
 760         if (cond & (G_IO_NVAL | G_IO_ERR | G_IO_HUP)) {
 761                 nameserver->udp_watch = 0;
 762                 return FALSE;
 763         }
 764
 765         sk = g_io_channel_unix_get_fd(nameserver->udp_channel);
 766
 767         len = recv(sk, buf, sizeof(buf), 0);
 768         if (len < 12)
 769                 return TRUE;
 770
 771         parse_response(nameserver, buf, len);
 772
 773         return TRUE;
 774 }
 775
 776 static int connect_udp_channel(struct resolv_nameserver *nameserver)
 777 {
 778         struct addrinfo hints, *rp;
 779         char portnr[6];
 780         int err, sk;
 781
 782         memset(&hints, 0, sizeof(hints));
 783         hints.ai_family = AF_UNSPEC;
 784         hints.ai_socktype = SOCK_DGRAM;
 785         hints.ai_flags = AI_PASSIVE | AI_NUMERICSERV | AI_NUMERICHOST;
 786
 787         sprintf(portnr, "%d", nameserver->port);
 788         err = getaddrinfo(nameserver->address, portnr, &hints, &rp);
 789         if (err)
 790                 return -EINVAL;
 791
 792         /*
 793          * Do not blindly copy this code elsewhere; it doesn't loop over the
 794          * results using ->ai_next as it should. That's OK in *this* case
 795          * because it was a numeric lookup; we *know* there's only one.
 796          */
 797         if (!rp)
 798                 return -EINVAL;
 799
 800         sk = socket(rp->ai_family, rp->ai_socktype, rp->ai_protocol);
 801         if (sk < 0) {
 802                 freeaddrinfo(rp);
 803                 return -EIO;
 804         }
 805
 806         /*
 807          * If nameserver points to localhost ip, their is no need to
 808          * bind the socket on any interface.
 809          */
 810         if (nameserver->resolv->index > 0 &&
 811                         strncmp(nameserver->address, "127.0.0.1", 9) != 0) {
 812                 char interface[IF_NAMESIZE];
 813
 814                 memset(interface, 0, IF_NAMESIZE);
 815                 if (if_indextoname(nameserver->resolv->index, interface)) {
 816                         if (setsockopt(sk, SOL_SOCKET, SO_BINDTODEVICE,
 817                                                 interface, IF_NAMESIZE) < 0) {
 818                                 close(sk);
 819                                 freeaddrinfo(rp);
 820                                 return -EIO;
 821                         }
 822                 }
 823         }
 824
 825         if (connect(sk, rp->ai_addr, rp->ai_addrlen) < 0) {
 826                 close(sk);
 827                 freeaddrinfo(rp);
 828                 return -EIO;
 829         }
 830
 831         freeaddrinfo(rp);
 832
 833         nameserver->udp_channel = g_io_channel_unix_new(sk);
 834         if (!nameserver->udp_channel) {
 835                 close(sk);
 836                 return -ENOMEM;
 837         }
 838
 839         g_io_channel_set_close_on_unref(nameserver->udp_channel, TRUE);
 840
 841         nameserver->udp_watch = g_io_add_watch(nameserver->udp_channel,
 842                                 G_IO_IN | G_IO_NVAL | G_IO_ERR | G_IO_HUP,
 843                                 received_udp_data, nameserver);
 844
 845         return 0;
 846 }
 847
 848 GResolv *g_resolv_new(int index)
 849 {
 850         GResolv *resolv;
 851
 852         if (index < 0)
 853                 return NULL;
 854
 855         resolv = g_try_new0(GResolv, 1);
 856         if (!resolv)
 857                 return NULL;
 858
 859         resolv->ref_count = 1;
 860
 861         resolv->result_family = AF_UNSPEC;
 862
 863         resolv->next_lookup_id = 1;
 864
 865         resolv->query_queue = g_queue_new();
 866         if (!resolv->query_queue) {
 867                 g_free(resolv);
 868                 return NULL;
 869         }
 870
 871         resolv->lookup_queue = g_queue_new();
 872         if (!resolv->lookup_queue) {
 873                 g_queue_free(resolv->query_queue);
 874                 g_free(resolv);
 875                 return NULL;
 876         }
 877
 878         resolv->index = index;
 879         resolv->nameserver_list = NULL;
 880
 881         res_ninit(&resolv->res);
 882
 883         return resolv;
 884 }
 885
 886 GResolv *g_resolv_ref(GResolv *resolv)
 887 {
 888         if (!resolv)
 889                 return NULL;
 890
 891         __sync_fetch_and_add(&resolv->ref_count, 1);
 892
 893         return resolv;
 894 }
 895
 896 void g_resolv_unref(GResolv *resolv)
 897 {
 898         struct resolv_query *query;
 899         struct resolv_lookup *lookup;
 900
 901         if (!resolv)
 902                 return;
 903
 904         if (__sync_fetch_and_sub(&resolv->ref_count, 1) != 1)
 905                 return;
 906
 907         while ((lookup = g_queue_pop_head(resolv->lookup_queue))) {
 908                 debug(resolv, "lookup %p id %d", lookup, lookup->id);
 909                 destroy_lookup(lookup);
 910         }
 911
 912         while ((query = g_queue_pop_head(resolv->query_queue))) {
 913                 debug(resolv, "query %p", query);
 914                 destroy_query(query);
 915         }
 916
 917         g_queue_free(resolv->query_queue);
 918         g_queue_free(resolv->lookup_queue);
 919
 920         flush_nameservers(resolv);
 921
 922         res_nclose(&resolv->res);
 923
 924         g_free(resolv);
 925 }
 926
 927 void g_resolv_set_debug(GResolv *resolv, GResolvDebugFunc func,
 928                                                 gpointer user_data)
 929 {
 930         if (!resolv)
 931                 return;
 932
 933         resolv->debug_func = func;
 934         resolv->debug_data = user_data;
 935 }
 936
 937 bool g_resolv_add_nameserver(GResolv *resolv, const char *address,
 938                                         uint16_t port, unsigned long flags)
 939 {
 940         struct resolv_nameserver *nameserver;
 941
 942         if (!resolv)
 943                 return false;
 944
 945         nameserver = g_try_new0(struct resolv_nameserver, 1);
 946         if (!nameserver)
 947                 return false;
 948
 949         nameserver->address = g_strdup(address);
 950         nameserver->port = port;
 951         nameserver->flags = flags;
 952         nameserver->resolv = resolv;
 953
 954         if (connect_udp_channel(nameserver) < 0) {
 955                 free_nameserver(nameserver);
 956                 return false;
 957         }
 958
 959         resolv->nameserver_list = g_list_append(resolv->nameserver_list,
 960                                                                 nameserver);
 961
 962         debug(resolv, "setting nameserver %s", address);
 963
 964         return true;
 965 }
 966
 967 void g_resolv_flush_nameservers(GResolv *resolv)
 968 {
 969         if (!resolv)
 970                 return;
 971
 972         flush_nameservers(resolv);
 973 }
 974
 975 static gint add_query(struct resolv_lookup *lookup, const char *hostname, int type)
 976 {
 977         struct resolv_query *query = g_try_new0(struct resolv_query, 1);
 978         unsigned char buf[4096];
 979         int len;
 980
 981         if (!query)
 982                 return -ENOMEM;
 983
 984         len = res_mkquery(ns_o_query, hostname, ns_c_in, type,
 985                                         NULL, 0, NULL, buf, sizeof(buf));
 986
 987         query->msgid = buf[0] << 8 | buf[1];
 988
 989         debug(lookup->resolv, "sending %d bytes", len);
 990
 991         query->nr_ns = send_query(lookup->resolv, buf, len);
 992         if (query->nr_ns <= 0) {
 993                 g_free(query);
 994                 return -EIO;
 995         }
 996
 997         query->resolv = lookup->resolv;
 998         query->lookup = lookup;
 999
1000         g_queue_push_tail(lookup->resolv->query_queue, query);
1001
1002         debug(lookup->resolv, "lookup %p id %d query %p", lookup, lookup->id,
1003                                                                         query);
1004
1005         query->timeout = g_timeout_add_seconds(5, query_timeout, query);
1006
1007         if (type == ns_t_aaaa)
1008                 lookup->ipv6_query = query;
1009         else
1010                 lookup->ipv4_query = query;
1011
1012         return 0;
1013 }
1014
1015 guint g_resolv_lookup_hostname(GResolv *resolv, const char *hostname,
1016                                 GResolvResultFunc func, gpointer user_data)
1017 {
1018         struct resolv_lookup *lookup;
1019
1020         if (!resolv)
1021                 return 0;
1022
1023         debug(resolv, "hostname %s", hostname);
1024
1025         if (!resolv->nameserver_list) {
1026                 int i;
1027
1028                 for (i = 0; i < resolv->res.nscount; i++) {
1029                         char buf[100];
1030                         int family = resolv->res.nsaddr_list[i].sin_family;
1031                         void *sa_addr = &resolv->res.nsaddr_list[i].sin_addr;
1032
1033                         if (family != AF_INET &&
1034                                         resolv->res._u._ext.nsaddrs[i]) {
1035                                 family = AF_INET6;
1036                                 sa_addr = &resolv->res._u._ext.nsaddrs[i]->sin6_addr;
1037                         }
1038
1039                         if (family != AF_INET && family != AF_INET6)
1040                                 continue;
1041
1042                         if (inet_ntop(family, sa_addr, buf, sizeof(buf)))
1043                                 g_resolv_add_nameserver(resolv, buf, 53, 0);
1044                 }
1045
1046                 if (!resolv->nameserver_list)
1047                         g_resolv_add_nameserver(resolv, "127.0.0.1", 53, 0);
1048         }
1049
1050         lookup = g_try_new0(struct resolv_lookup, 1);
1051         if (!lookup)
1052                 return 0;
1053
1054         lookup->resolv = resolv;
1055         lookup->result_func = func;
1056         lookup->result_data = user_data;
1057         lookup->id = resolv->next_lookup_id++;
1058
1059         if (resolv->result_family != AF_INET6) {
1060                 if (add_query(lookup, hostname, ns_t_a)) {
1061                         g_free(lookup);
1062                         return -EIO;
1063                 }
1064         }
1065
1066         if (resolv->result_family != AF_INET) {
1067                 if (add_query(lookup, hostname, ns_t_aaaa)) {
1068                         if (resolv->result_family != AF_INET6) {
1069                                 g_queue_remove(resolv->query_queue,
1070                                                 lookup->ipv4_query);
1071                                 destroy_query(lookup->ipv4_query);
1072                         }
1073
1074                         g_free(lookup);
1075                         return -EIO;
1076                 }
1077         }
1078
1079         g_queue_push_tail(resolv->lookup_queue, lookup);
1080
1081         debug(resolv, "lookup %p id %d", lookup, lookup->id);
1082
1083         return lookup->id;
1084 }
1085
1086 bool g_resolv_cancel_lookup(GResolv *resolv, guint id)
1087 {
1088         struct resolv_lookup *lookup;
1089         GList *list;
1090
1091         debug(resolv, "lookup id %d", id);
1092
1093         list = g_queue_find_custom(resolv->lookup_queue,
1094                                 GUINT_TO_POINTER(id), compare_lookup_id);
1095
1096         if (!list)
1097                 return false;
1098
1099         lookup = list->data;
1100
1101         debug(resolv, "lookup %p", lookup);
1102
1103         g_queue_remove(resolv->lookup_queue, lookup);
1104         destroy_lookup(lookup);
1105
1106         return true;
1107 }
1108
1109 bool g_resolv_set_address_family(GResolv *resolv, int family)
1110 {
1111         if (!resolv)
1112                 return false;
1113
1114         if (family != AF_UNSPEC && family != AF_INET && family != AF_INET6)
1115                 return false;
1116
1117         resolv->result_family = family;
1118
1119         return true;
1120 }