gweb/gresolv.c

   1 /*
   2  *
   3  *  Resolver library with GLib integration
   4  *
   5  *  Copyright (C) 2009-2010  Intel Corporation. All rights reserved.
   6  *
   7  *  This program is free software; you can redistribute it and/or modify
   8  *  it under the terms of the GNU General Public License version 2 as
   9  *  published by the Free Software Foundation.
  10  *
  11  *  This program is distributed in the hope that it will be useful,
  12  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  *  GNU General Public License for more details.
  15  *
  16  *  You should have received a copy of the GNU General Public License
  17  *  along with this program; if not, write to the Free Software
  18  *  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  19  *
  20  */
  21
  22 #ifdef HAVE_CONFIG_H
  23 #include <config.h>
  24 #endif
  25
  26 #include <errno.h>
  27 #include <unistd.h>
  28 #include <stdarg.h>
  29 #include <string.h>
  30 #include <stdlib.h>
  31 #include <resolv.h>
  32 #include <sys/types.h>
  33 #include <sys/socket.h>
  34 #include <netdb.h>
  35 #include <arpa/inet.h>
  36 #include <arpa/nameser.h>
  37
  38 #include "gresolv.h"
  39
  40 struct sort_result {
  41         int precedence;
  42         int src_scope;
  43         int dst_scope;
  44         int src_label;
  45         int dst_label;
  46         gboolean reachable;
  47         union {
  48                 struct sockaddr sa;
  49                 struct sockaddr_in sin;
  50                 struct sockaddr_in6 sin6;
  51         } src;
  52         union {
  53                 struct sockaddr sa;
  54                 struct sockaddr_in sin;
  55                 struct sockaddr_in6 sin6;
  56         } dst;
  57 };
  58
  59 struct resolv_query;
  60
  61 struct resolv_lookup {
  62         GResolv *resolv;
  63         guint id;
  64
  65         int nr_results;
  66         struct sort_result *results;
  67
  68         struct resolv_query *ipv4_query;
  69         struct resolv_query *ipv6_query;
  70
  71         guint ipv4_status;
  72         guint ipv6_status;
  73
  74         GResolvResultFunc result_func;
  75         gpointer result_data;
  76 };
  77
  78 struct resolv_query {
  79         GResolv *resolv;
  80
  81         guint timeout;
  82
  83         uint16_t msgid;
  84
  85         struct resolv_lookup *lookup;
  86 };
  87
  88 struct resolv_nameserver {
  89         GResolv *resolv;
  90
  91         char *address;
  92         uint16_t port;
  93         unsigned long flags;
  94
  95         GIOChannel *udp_channel;
  96         guint udp_watch;
  97 };
  98
  99 struct _GResolv {
 100         gint ref_count;
 101
 102         guint next_lookup_id;
 103         GQueue *lookup_queue;
 104         GQueue *query_queue;
 105
 106         int index;
 107         GList *nameserver_list;
 108
 109         struct __res_state res;
 110
 111         GResolvDebugFunc debug_func;
 112         gpointer debug_data;
 113 };
 114
 115 static inline void debug(GResolv *resolv, const char *format, ...)
 116 {
 117         char str[256];
 118         va_list ap;
 119
 120         if (resolv->debug_func == NULL)
 121                 return;
 122
 123         va_start(ap, format);
 124
 125         if (vsnprintf(str, sizeof(str), format, ap) > 0)
 126                 resolv->debug_func(str, resolv->debug_data);
 127
 128         va_end(ap);
 129 }
 130
 131 static void destroy_query(struct resolv_query *query)
 132 {
 133         if (query->timeout > 0)
 134                 g_source_remove(query->timeout);
 135
 136         g_free(query);
 137 }
 138
 139 static void destroy_lookup(struct resolv_lookup *lookup)
 140 {
 141         if (lookup->ipv4_query != NULL) {
 142                 g_queue_remove(lookup->resolv->query_queue,
 143                                                 lookup->ipv4_query);
 144                 destroy_query(lookup->ipv4_query);
 145         }
 146
 147         if (lookup->ipv6_query != NULL) {
 148                 g_queue_remove(lookup->resolv->query_queue,
 149                                                 lookup->ipv6_query);
 150                 destroy_query(lookup->ipv6_query);
 151         }
 152
 153         g_free(lookup->results);
 154         g_free(lookup);
 155 }
 156
 157 static void find_srcaddr(struct sort_result *res)
 158 {
 159         socklen_t sl = sizeof(res->src);
 160         int fd;
 161
 162         fd = socket(res->dst.sa.sa_family, SOCK_DGRAM, IPPROTO_IP);
 163         if (fd < 0)
 164                 return;
 165
 166         if (connect(fd, &res->dst.sa, sizeof(res->dst)) < 0) {
 167                 close(fd);
 168                 return;
 169         }
 170
 171         if (getsockname(fd, &res->src.sa, &sl) < 0) {
 172                 close(fd);
 173                 return;
 174         }
 175
 176         res->reachable = TRUE;
 177         close(fd);
 178 }
 179
 180 struct gai_table
 181 {
 182         unsigned char addr[NS_IN6ADDRSZ];
 183         int mask;
 184         int value;
 185 };
 186
 187 static const struct gai_table gai_labels[] = {
 188         {
 189                 .addr = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 190                           0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01 },
 191                 .mask = 128,
 192                 .value = 0,
 193         }, {
 194                 .addr = { 0x20, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 195                           0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
 196                 .mask = 16,
 197                 .value = 2,
 198         }, {
 199                 .addr = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 200                           0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
 201                 .mask = 96,
 202                 .value = 3,
 203         }, {
 204                 .addr = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 205                           0x00, 0x00, 0xff, 0xff, 0x00, 0x00, 0x00, 0x00 },
 206                 .mask = 96,
 207                 .value = 4,
 208         }, {
 209                 /* Variations from RFC 3484, matching glibc behaviour */
 210                 .addr = { 0xfe, 0xc0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 211                           0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
 212                 .mask = 10,
 213                 .value = 5,
 214         }, {
 215                 .addr = { 0xfc, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 216                           0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
 217                 .mask = 7,
 218                 .value = 6,
 219         }, {
 220                 .addr = { 0x20, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 221                           0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
 222                 .mask = 32,
 223                 .value = 7,
 224         }, {
 225                 /* catch-all */
 226                 .addr = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 227                           0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
 228                 .mask = 0,
 229                 .value = 1,
 230         }
 231 };
 232
 233 static const struct gai_table gai_precedences[] = {
 234         {
 235                 .addr = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 236                           0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01 },
 237                 .mask = 128,
 238                 .value = 50,
 239         }, {
 240                 .addr = { 0x20, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 241                           0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
 242                 .mask = 16,
 243                 .value = 30,
 244         }, {
 245                 .addr = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 246                           0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
 247                 .mask = 96,
 248                 .value = 20,
 249         }, {
 250                 .addr = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 251                           0x00, 0x00, 0xff, 0xff, 0x00, 0x00, 0x00, 0x00 },
 252                 .mask = 96,
 253                 .value = 10,
 254         }, {
 255                 .addr = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 256                           0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
 257                 .mask = 0,
 258                 .value = 40,
 259         }
 260 };
 261
 262 static unsigned char v4mapped[] = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 263                                     0x00, 0x00, 0xff, 0xff, 0x00, 0x00, 0x00, 0x00 };
 264
 265 static gboolean mask_compare(const unsigned char *one,
 266                                         const unsigned char *two, int mask)
 267 {
 268         if (mask > 8) {
 269                 if (memcmp(one, two, mask / 8))
 270                         return FALSE;
 271                 one += mask / 8;
 272                 two += mask / 8;
 273                 mask %= 8;
 274         }
 275
 276         if (mask && ((*one ^ *two) >> (8 - mask)))
 277                 return FALSE;
 278
 279         return TRUE;
 280 }
 281
 282 static int match_gai_table(struct sockaddr *sa, const struct gai_table *tbl)
 283 {
 284         struct sockaddr_in *sin = (void *)sa;
 285         struct sockaddr_in6 *sin6 = (void *)sa;
 286         void *addr;
 287
 288         if (sa->sa_family == AF_INET) {
 289                 addr = v4mapped;
 290                 memcpy(v4mapped+12, &sin->sin_addr, NS_INADDRSZ);
 291         } else
 292                 addr = &sin6->sin6_addr;
 293
 294         while (1) {
 295                 if (mask_compare(addr, tbl->addr, tbl->mask))
 296                         return tbl->value;
 297                 tbl++;
 298         }
 299 }
 300
 301 #define DQUAD(_a,_b,_c,_d) ( ((_a)<<24) | ((_b)<<16) | ((_c)<<8) | (_d) )
 302 #define V4MATCH(addr, a,b,c,d, m) ( ((addr) ^ DQUAD(a,b,c,d)) >> (32 - (m)) )
 303
 304 #define RFC3484_SCOPE_LINK      2
 305 #define RFC3484_SCOPE_SITE      5
 306 #define RFC3484_SCOPE_GLOBAL    14
 307
 308 static int addr_scope(struct sockaddr *sa)
 309 {
 310         if (sa->sa_family == AF_INET) {
 311                 struct sockaddr_in *sin = (void *)sa;
 312                 guint32 addr = ntohl(sin->sin_addr.s_addr);
 313
 314                 if (V4MATCH(addr, 169,254,0,0, 16) ||
 315                                         V4MATCH(addr, 127,0,0,0, 8))
 316                         return RFC3484_SCOPE_LINK;
 317
 318                 /* Site-local */
 319                 if (V4MATCH(addr, 10,0,0,0, 8) ||
 320                                 V4MATCH(addr, 172,16,0,0, 12) ||
 321                                 V4MATCH(addr, 192,168,0,0, 16))
 322                         return RFC3484_SCOPE_SITE;
 323
 324                 /* Global */
 325                 return RFC3484_SCOPE_GLOBAL;
 326         } else {
 327                 struct sockaddr_in6 *sin6 = (void *)sa;
 328
 329                 /* Multicast addresses have a 4-bit scope field */
 330                 if (IN6_IS_ADDR_MULTICAST(&sin6->sin6_addr))
 331                         return sin6->sin6_addr.s6_addr[1] & 0xf;
 332
 333                 if (IN6_IS_ADDR_LINKLOCAL(&sin6->sin6_addr) ||
 334                                 IN6_IS_ADDR_LOOPBACK(&sin6->sin6_addr))
 335                         return RFC3484_SCOPE_LINK;
 336
 337                 if (IN6_IS_ADDR_SITELOCAL(&sin6->sin6_addr))
 338                         return RFC3484_SCOPE_SITE;
 339
 340                 return RFC3484_SCOPE_GLOBAL;
 341         }
 342 }
 343
 344 static int rfc3484_compare(const void *__one, const void *__two)
 345 {
 346         const struct sort_result *one = __one;
 347         const struct sort_result *two = __two;
 348
 349         /* Rule 1: Avoid unusable destinations */
 350         if (one->reachable && !two->reachable)
 351                 return -1;
 352         else if (two->reachable && !one->reachable)
 353                 return 1;
 354
 355         /* Rule 2: Prefer matching scope */
 356         if (one->dst_scope == one->src_scope &&
 357                                 two->dst_scope != two->src_scope)
 358                 return -1;
 359         else if (two->dst_scope == two->src_scope &&
 360                                 one->dst_scope != one->src_scope)
 361                 return 1;
 362
 363         /* Rule 3: Avoid deprecated addresses */
 364
 365         /* Rule 4: Prefer home addresses */
 366
 367         /* Rule 5: Prefer matching label */
 368         if (one->dst_label == one->src_label &&
 369                                 two->dst_label != two->src_label)
 370                 return -1;
 371         else if (two->dst_label == two->src_label &&
 372                                 one->dst_label != one->src_label)
 373                 return 1;
 374
 375         /* Rule 6: Prefer higher precedence */
 376         if (one->precedence > two->precedence)
 377                 return -1;
 378         else if (two->precedence > one->precedence)
 379                 return 1;
 380
 381         /* Rule 7: Prefer native transport */
 382
 383         /* Rule 8: Prefer smaller scope */
 384         if (one->dst_scope != two->dst_scope)
 385                 return one->dst_scope - two->dst_scope;
 386
 387         /* Rule 9: Use longest matching prefix */
 388         if (one->dst.sa.sa_family == AF_INET) {
 389                 /*
 390                  * Rule 9 is meaningless and counterproductive for Legacy IP
 391                  * unless perhaps we can tell that it's actually on the local
 392                  * subnet. But we don't (yet) have local interface config
 393                  * information, so do nothing here for Legacy IP for now.
 394                  */
 395         } else {
 396                 int i;
 397
 398                 for (i = 0; i < 4; i++) {
 399                         guint32 cmp_one, cmp_two;
 400
 401                         cmp_one = one->src.sin6.sin6_addr.s6_addr32[i] ^
 402                                         one->dst.sin6.sin6_addr.s6_addr32[i];
 403                         cmp_two = two->src.sin6.sin6_addr.s6_addr32[i] ^
 404                                         two->dst.sin6.sin6_addr.s6_addr32[i];
 405
 406                         if (!cmp_two && !cmp_one)
 407                                 continue;
 408
 409                         if (cmp_one && !cmp_two)
 410                                 return 1;
 411                         if (cmp_two && !cmp_one)
 412                                 return -1;
 413
 414                         /* g_bit_storage() is effectively fls() */
 415                         cmp_one = g_bit_storage(ntohl(cmp_one));
 416                         cmp_two = g_bit_storage(ntohl(cmp_two));
 417
 418                         if (cmp_one == cmp_two)
 419                                 break;
 420
 421                         return cmp_one - cmp_two;
 422                 }
 423         }
 424
 425
 426         /* Rule 10: Otherwise, leave the order unchanged */
 427         if (one < two)
 428                 return -1;
 429         else
 430                 return 1;
 431 }
 432
 433 static void rfc3484_sort_results(struct resolv_lookup *lookup)
 434 {
 435         int i;
 436
 437         for (i = 0; i < lookup->nr_results; i++) {
 438                 struct sort_result *res = &lookup->results[i];
 439                 find_srcaddr(res);
 440                 res->precedence = match_gai_table(&res->dst.sa,
 441                                                         gai_precedences);
 442                 res->dst_label = match_gai_table(&res->dst.sa, gai_labels);
 443                 res->src_label = match_gai_table(&res->src.sa, gai_labels);
 444                 res->dst_scope = addr_scope(&res->dst.sa);
 445                 res->src_scope = addr_scope(&res->src.sa);
 446         }
 447
 448         qsort(lookup->results, lookup->nr_results,
 449                         sizeof(struct sort_result), rfc3484_compare);
 450 }
 451
 452 static void sort_and_return_results(struct resolv_lookup *lookup)
 453 {
 454         char buf[100];
 455         GResolvResultStatus status;
 456         char **results = g_try_new0(char *, lookup->nr_results + 1);
 457         int i, n = 0;
 458
 459         if (!results)
 460                 return;
 461
 462         rfc3484_sort_results(lookup);
 463
 464         for (i = 0; i < lookup->nr_results; i++) {
 465                 if (lookup->results[i].dst.sa.sa_family == AF_INET) {
 466                         if (inet_ntop(AF_INET,
 467                                         &lookup->results[i].dst.sin.sin_addr,
 468                                         buf, sizeof(buf)) == NULL)
 469                                 continue;
 470                 } else if (lookup->results[i].dst.sa.sa_family == AF_INET6) {
 471                         if (inet_ntop(AF_INET6,
 472                                         &lookup->results[i].dst.sin6.sin6_addr,
 473                                         buf, sizeof(buf)) == NULL)
 474                                 continue;
 475                 } else
 476                         continue;
 477
 478                 results[n++] = strdup(buf);
 479         }
 480
 481         results[n++] = NULL;
 482
 483         status = lookup->ipv4_status;
 484
 485         if (status == G_RESOLV_RESULT_STATUS_SUCCESS)
 486                 status = lookup->ipv6_status;
 487
 488         lookup->result_func(status, results, lookup->result_data);
 489
 490         g_strfreev(results);
 491         g_queue_remove(lookup->resolv->lookup_queue, lookup);
 492         destroy_lookup(lookup);
 493 }
 494
 495 static gboolean query_timeout(gpointer user_data)
 496 {
 497         struct resolv_query *query = user_data;
 498         struct resolv_lookup *lookup = query->lookup;
 499         GResolv *resolv = query->resolv;
 500
 501         query->timeout = 0;
 502
 503         if (query == lookup->ipv4_query) {
 504                 lookup->ipv4_status = G_RESOLV_RESULT_STATUS_NO_RESPONSE;
 505                 lookup->ipv4_query = NULL;
 506         } else if (query == lookup->ipv6_query) {
 507                 lookup->ipv6_status = G_RESOLV_RESULT_STATUS_NO_RESPONSE;
 508                 lookup->ipv6_query = NULL;
 509         }
 510
 511         if (lookup->ipv4_query == NULL && lookup->ipv4_query == NULL)
 512                 sort_and_return_results(lookup);
 513
 514         destroy_query(query);
 515         g_queue_remove(resolv->query_queue, query);
 516
 517         return FALSE;
 518 }
 519
 520 static void free_nameserver(struct resolv_nameserver *nameserver)
 521 {
 522         if (nameserver == NULL)
 523                 return;
 524
 525         if (nameserver->udp_watch > 0)
 526                 g_source_remove(nameserver->udp_watch);
 527
 528         if (nameserver->udp_channel != NULL)
 529                 g_io_channel_unref(nameserver->udp_channel);
 530
 531         g_free(nameserver->address);
 532         g_free(nameserver);
 533 }
 534
 535 static void flush_nameservers(GResolv *resolv)
 536 {
 537         GList *list;
 538
 539         for (list = g_list_first(resolv->nameserver_list);
 540                                         list; list = g_list_next(list))
 541                 free_nameserver(list->data);
 542
 543         g_list_free(resolv->nameserver_list);
 544         resolv->nameserver_list = NULL;
 545 }
 546
 547 static int send_query(GResolv *resolv, const unsigned char *buf, int len)
 548 {
 549         GList *list;
 550
 551         if (resolv->nameserver_list == NULL)
 552                 return -ENOENT;
 553
 554         for (list = g_list_first(resolv->nameserver_list);
 555                                         list; list = g_list_next(list)) {
 556                 struct resolv_nameserver *nameserver = list->data;
 557                 int sk, sent;
 558
 559                 if (nameserver->udp_channel == NULL)
 560                         continue;
 561
 562                 sk = g_io_channel_unix_get_fd(nameserver->udp_channel);
 563
 564                 sent = send(sk, buf, len, 0);
 565                 if (sent < 0)
 566                         continue;
 567         }
 568
 569         return 0;
 570 }
 571
 572 static gint compare_lookup_id(gconstpointer a, gconstpointer b)
 573 {
 574         const struct resolv_lookup *lookup = a;
 575         guint id = GPOINTER_TO_UINT(b);
 576
 577         if (lookup->id < id)
 578                 return -1;
 579
 580         if (lookup->id > id)
 581                 return 1;
 582
 583         return 0;
 584 }
 585
 586 static gint compare_query_msgid(gconstpointer a, gconstpointer b)
 587 {
 588         const struct resolv_query *query = a;
 589         uint16_t msgid = GPOINTER_TO_UINT(b);
 590
 591         if (query->msgid < msgid)
 592                 return -1;
 593
 594         if (query->msgid > msgid)
 595                 return 1;
 596
 597         return 0;
 598 }
 599
 600 static void add_result(struct resolv_lookup *lookup, int family,
 601                                                         const void *data)
 602 {
 603         int n = lookup->nr_results++;
 604         lookup->results = g_realloc(lookup->results,
 605                                         sizeof(struct sort_result) * (n + 1));
 606
 607         memset(&lookup->results[n], 0, sizeof(struct sort_result));
 608
 609         lookup->results[n].dst.sa.sa_family = family;
 610         if (family == AF_INET)
 611                 memcpy(&lookup->results[n].dst.sin.sin_addr,
 612                                                 data, NS_INADDRSZ);
 613         else
 614                 memcpy(&lookup->results[n].dst.sin6.sin6_addr,
 615                                                 data, NS_IN6ADDRSZ);
 616 }
 617
 618 static void parse_response(struct resolv_nameserver *nameserver,
 619                                         const unsigned char *buf, int len)
 620 {
 621         GResolv *resolv = nameserver->resolv;
 622         GResolvResultStatus status;
 623         struct resolv_query *query;
 624         struct resolv_lookup *lookup;
 625         GList *list;
 626         ns_msg msg;
 627         ns_rr rr;
 628         int i, rcode, count;
 629
 630         debug(resolv, "response from %s", nameserver->address);
 631
 632         ns_initparse(buf, len, &msg);
 633
 634         rcode = ns_msg_getflag(msg, ns_f_rcode);
 635         count = ns_msg_count(msg, ns_s_an);
 636
 637         debug(resolv, "msg id: 0x%04x rcode: %d count: %d",
 638                                         ns_msg_id(msg), rcode, count);
 639
 640         switch (rcode) {
 641         case 0:
 642                 status = G_RESOLV_RESULT_STATUS_SUCCESS;
 643                 break;
 644         case 1:
 645                 status = G_RESOLV_RESULT_STATUS_FORMAT_ERROR;
 646                 break;
 647         case 2:
 648                 status = G_RESOLV_RESULT_STATUS_SERVER_FAILURE;
 649                 break;
 650         case 3:
 651                 status = G_RESOLV_RESULT_STATUS_NAME_ERROR;
 652                 break;
 653         case 4:
 654                 status = G_RESOLV_RESULT_STATUS_NOT_IMPLEMENTED;
 655                 break;
 656         case 5:
 657                 status = G_RESOLV_RESULT_STATUS_REFUSED;
 658                 break;
 659         default:
 660                 status = G_RESOLV_RESULT_STATUS_ERROR;
 661                 break;
 662         }
 663
 664         list = g_queue_find_custom(resolv->query_queue,
 665                         GUINT_TO_POINTER(ns_msg_id(msg)), compare_query_msgid);
 666         if (!list)
 667                 return;
 668
 669         query = list->data;
 670         lookup = query->lookup;
 671
 672         if (query == lookup->ipv6_query) {
 673                 lookup->ipv6_status = status;
 674                 lookup->ipv6_query = NULL;
 675         } else if (query == lookup->ipv4_query) {
 676                 lookup->ipv4_status = status;
 677                 lookup->ipv4_query = NULL;
 678         }
 679
 680         for (i = 0; i < count; i++) {
 681                 ns_parserr(&msg, ns_s_an, i, &rr);
 682
 683                 if (ns_rr_class(rr) != ns_c_in)
 684                         continue;
 685
 686                 g_assert(offsetof(struct sockaddr_in, sin_addr) ==
 687                                 offsetof(struct sockaddr_in6, sin6_flowinfo));
 688
 689                 if (ns_rr_type(rr) == ns_t_a &&
 690                                         ns_rr_rdlen(rr) == NS_INADDRSZ) {
 691                         add_result(lookup, AF_INET, ns_rr_rdata(rr));
 692                 } else if (ns_rr_type(rr) == ns_t_aaaa &&
 693                                         ns_rr_rdlen(rr) == NS_IN6ADDRSZ) {
 694                         add_result(lookup, AF_INET6, ns_rr_rdata(rr));
 695                 }
 696         }
 697
 698         if (lookup->ipv4_query == NULL && lookup->ipv6_query == NULL)
 699                 sort_and_return_results(lookup);
 700
 701         destroy_query(query);
 702         g_queue_remove(resolv->query_queue, query);
 703 }
 704
 705 static gboolean received_udp_data(GIOChannel *channel, GIOCondition cond,
 706                                                         gpointer user_data)
 707 {
 708         struct resolv_nameserver *nameserver = user_data;
 709         unsigned char buf[4096];
 710         int sk, len;
 711
 712         if (cond & (G_IO_NVAL | G_IO_ERR | G_IO_HUP)) {
 713                 nameserver->udp_watch = 0;
 714                 return FALSE;
 715         }
 716
 717         sk = g_io_channel_unix_get_fd(nameserver->udp_channel);
 718
 719         len = recv(sk, buf, sizeof(buf), 0);
 720         if (len < 12)
 721                 return TRUE;
 722
 723         parse_response(nameserver, buf, len);
 724
 725         return TRUE;
 726 }
 727
 728 static int connect_udp_channel(struct resolv_nameserver *nameserver)
 729 {
 730         struct addrinfo hints, *rp;
 731         char portnr[6];
 732         int err, sk;
 733
 734         memset(&hints, 0, sizeof(hints));
 735         hints.ai_family = AF_UNSPEC;
 736         hints.ai_socktype = SOCK_DGRAM;
 737         hints.ai_flags = AI_PASSIVE | AI_NUMERICSERV | AI_NUMERICHOST;
 738
 739         sprintf(portnr, "%d", nameserver->port);
 740         err = getaddrinfo(nameserver->address, portnr, &hints, &rp);
 741         if (err)
 742                 return -EINVAL;
 743
 744         /*
 745          * Do not blindly copy this code elsewhere; it doesn't loop over the
 746          * results using ->ai_next as it should. That's OK in *this* case
 747          * because it was a numeric lookup; we *know* there's only one.
 748          */
 749         if (!rp)
 750                 return -EINVAL;
 751
 752         sk = socket(rp->ai_family, rp->ai_socktype, rp->ai_protocol);
 753         if (sk < 0) {
 754                 freeaddrinfo(rp);
 755                 return -EIO;
 756         }
 757
 758         if (connect(sk, rp->ai_addr, rp->ai_addrlen) < 0) {
 759                 close(sk);
 760                 freeaddrinfo(rp);
 761                 return -EIO;
 762         }
 763
 764         freeaddrinfo(rp);
 765
 766         nameserver->udp_channel = g_io_channel_unix_new(sk);
 767         if (nameserver->udp_channel == NULL) {
 768                 close(sk);
 769                 return -ENOMEM;
 770         }
 771
 772         g_io_channel_set_close_on_unref(nameserver->udp_channel, TRUE);
 773
 774         nameserver->udp_watch = g_io_add_watch(nameserver->udp_channel,
 775                                 G_IO_IN | G_IO_NVAL | G_IO_ERR | G_IO_HUP,
 776                                 received_udp_data, nameserver);
 777
 778         return 0;
 779 }
 780
 781 GResolv *g_resolv_new(int index)
 782 {
 783         GResolv *resolv;
 784
 785         if (index < 0)
 786                 return NULL;
 787
 788         resolv = g_try_new0(GResolv, 1);
 789         if (resolv == NULL)
 790                 return NULL;
 791
 792         resolv->ref_count = 1;
 793
 794         resolv->next_lookup_id = 1;
 795
 796         resolv->query_queue = g_queue_new();
 797         if (resolv->query_queue == NULL) {
 798                 g_free(resolv);
 799                 return NULL;
 800         }
 801
 802         resolv->lookup_queue = g_queue_new();
 803         if (resolv->lookup_queue == NULL) {
 804                 g_queue_free(resolv->query_queue);
 805                 g_free(resolv);
 806                 return NULL;
 807         }
 808
 809         resolv->index = index;
 810         resolv->nameserver_list = NULL;
 811
 812         res_ninit(&resolv->res);
 813
 814         return resolv;
 815 }
 816
 817 GResolv *g_resolv_ref(GResolv *resolv)
 818 {
 819         if (resolv == NULL)
 820                 return NULL;
 821
 822         g_atomic_int_inc(&resolv->ref_count);
 823
 824         return resolv;
 825 }
 826
 827 void g_resolv_unref(GResolv *resolv)
 828 {
 829         struct resolv_query *query;
 830
 831         if (resolv == NULL)
 832                 return;
 833
 834         if (g_atomic_int_dec_and_test(&resolv->ref_count) == FALSE)
 835                 return;
 836
 837         while ((query = g_queue_pop_head(resolv->query_queue)))
 838                 destroy_query(query);
 839
 840         g_queue_free(resolv->query_queue);
 841         g_queue_free(resolv->lookup_queue);
 842
 843         flush_nameservers(resolv);
 844
 845         res_nclose(&resolv->res);
 846
 847         g_free(resolv);
 848 }
 849
 850 void g_resolv_set_debug(GResolv *resolv, GResolvDebugFunc func,
 851                                                 gpointer user_data)
 852 {
 853         if (resolv == NULL)
 854                 return;
 855
 856         resolv->debug_func = func;
 857         resolv->debug_data = user_data;
 858 }
 859
 860 gboolean g_resolv_add_nameserver(GResolv *resolv, const char *address,
 861                                         uint16_t port, unsigned long flags)
 862 {
 863         struct resolv_nameserver *nameserver;
 864
 865         if (resolv == NULL)
 866                 return FALSE;
 867
 868         nameserver = g_try_new0(struct resolv_nameserver, 1);
 869         if (nameserver == NULL)
 870                 return FALSE;
 871
 872         nameserver->address = g_strdup(address);
 873         nameserver->port = port;
 874         nameserver->flags = flags;
 875
 876         if (connect_udp_channel(nameserver) < 0) {
 877                 free_nameserver(nameserver);
 878                 return FALSE;
 879         }
 880
 881         nameserver->resolv = resolv;
 882
 883         resolv->nameserver_list = g_list_append(resolv->nameserver_list,
 884                                                                 nameserver);
 885
 886         debug(resolv, "setting nameserver %s", address);
 887
 888         return TRUE;
 889 }
 890
 891 void g_resolv_flush_nameservers(GResolv *resolv)
 892 {
 893         if (resolv == NULL)
 894                 return;
 895
 896         flush_nameservers(resolv);
 897 }
 898
 899 static gint add_query(struct resolv_lookup *lookup, const char *hostname, int type)
 900 {
 901         struct resolv_query *query = g_try_new0(struct resolv_query, 1);
 902         unsigned char buf[4096];
 903         int len;
 904
 905         if (query == NULL)
 906                 return -ENOMEM;
 907
 908         len = res_mkquery(ns_o_query, hostname, ns_c_in, type,
 909                                         NULL, 0, NULL, buf, sizeof(buf));
 910
 911         query->msgid = buf[0] << 8 | buf[1];
 912
 913         if (send_query(lookup->resolv, buf, len) < 0) {
 914                 g_free(query);
 915                 return -EIO;
 916         }
 917
 918         query->resolv = lookup->resolv;
 919         query->lookup = lookup;
 920
 921         g_queue_push_tail(lookup->resolv->query_queue, query);
 922
 923         query->timeout = g_timeout_add_seconds(5, query_timeout, query);
 924
 925         if (type == ns_t_aaaa)
 926                 lookup->ipv6_query = query;
 927         else
 928                 lookup->ipv4_query = query;
 929
 930         return 0;
 931 }
 932
 933 guint g_resolv_lookup_hostname(GResolv *resolv, const char *hostname,
 934                                 GResolvResultFunc func, gpointer user_data)
 935 {
 936         struct resolv_lookup *lookup;
 937
 938         debug(resolv, "lookup hostname %s", hostname);
 939
 940         if (resolv == NULL)
 941                 return 0;
 942
 943         if (resolv->nameserver_list == NULL) {
 944                 int i;
 945
 946                 for (i = 0; i < resolv->res.nscount; i++) {
 947                         char buf[100];
 948                         int family = resolv->res.nsaddr_list[i].sin_family;
 949                         void *sa_addr = &resolv->res.nsaddr_list[i].sin_addr;
 950
 951                         if (family != AF_INET &&
 952                                         resolv->res._u._ext.nsaddrs[i]) {
 953                                 family = AF_INET6;
 954                                 sa_addr = &resolv->res._u._ext.nsaddrs[i]->sin6_addr;
 955                         }
 956
 957                         if (family != AF_INET && family != AF_INET6)
 958                                 continue;
 959
 960                         if (inet_ntop(family, sa_addr, buf, sizeof(buf)))
 961                                 g_resolv_add_nameserver(resolv, buf, 53, 0);
 962                 }
 963
 964                 if (resolv->nameserver_list == NULL)
 965                         g_resolv_add_nameserver(resolv, "127.0.0.1", 53, 0);
 966         }
 967
 968         lookup = g_try_new0(struct resolv_lookup, 1);
 969         if (lookup == NULL)
 970                 return 0;
 971
 972         lookup->resolv = resolv;
 973         lookup->result_func = func;
 974         lookup->result_data = user_data;
 975         lookup->id = resolv->next_lookup_id++;
 976
 977         if (add_query(lookup, hostname, ns_t_a)) {
 978                 g_free(lookup);
 979                 return -EIO;
 980         }
 981
 982         if (add_query(lookup, hostname, ns_t_aaaa)) {
 983                 destroy_query(lookup->ipv4_query);
 984                 g_queue_remove(resolv->query_queue, lookup->ipv4_query);
 985                 g_free(lookup);
 986                 return -EIO;
 987         }
 988
 989         g_queue_push_tail(resolv->lookup_queue, lookup);
 990         return lookup->id;
 991 }
 992
 993 gboolean g_resolv_cancel_lookup(GResolv *resolv, guint id)
 994 {
 995         GList *list;
 996
 997         list = g_queue_find_custom(resolv->lookup_queue,
 998                                 GUINT_TO_POINTER(id), compare_lookup_id);
 999
1000         if (list == NULL)
1001                 return FALSE;
1002
1003         destroy_lookup(list->data);
1004         g_queue_remove(resolv->query_queue, list->data);
1005
1006         return TRUE;
1007 }