gweb/gresolv.c

   1 /*
   2  *
   3  *  Resolver library with GLib integration
   4  *
   5  *  Copyright (C) 2009-2012  Intel Corporation. All rights reserved.
   6  *
   7  *  This program is free software; you can redistribute it and/or modify
   8  *  it under the terms of the GNU General Public License version 2 as
   9  *  published by the Free Software Foundation.
  10  *
  11  *  This program is distributed in the hope that it will be useful,
  12  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  *  GNU General Public License for more details.
  15  *
  16  *  You should have received a copy of the GNU General Public License
  17  *  along with this program; if not, write to the Free Software
  18  *  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  19  *
  20  */
  21
  22 #ifdef HAVE_CONFIG_H
  23 #include <config.h>
  24 #endif
  25
  26 #include <errno.h>
  27 #include <unistd.h>
  28 #include <stdarg.h>
  29 #include <string.h>
  30 #include <stdlib.h>
  31 #include <resolv.h>
  32 #include <sys/types.h>
  33 #include <sys/socket.h>
  34 #include <netdb.h>
  35 #include <arpa/inet.h>
  36 #include <arpa/nameser.h>
  37 #include <net/if.h>
  38
  39 #include "gresolv.h"
  40
  41 struct sort_result {
  42         int precedence;
  43         int src_scope;
  44         int dst_scope;
  45         int src_label;
  46         int dst_label;
  47         gboolean reachable;
  48         union {
  49                 struct sockaddr sa;
  50                 struct sockaddr_in sin;
  51                 struct sockaddr_in6 sin6;
  52         } src;
  53         union {
  54                 struct sockaddr sa;
  55                 struct sockaddr_in sin;
  56                 struct sockaddr_in6 sin6;
  57         } dst;
  58 };
  59
  60 struct resolv_query;
  61
  62 struct resolv_lookup {
  63         GResolv *resolv;
  64         guint id;
  65
  66         int nr_results;
  67         struct sort_result *results;
  68
  69         struct resolv_query *ipv4_query;
  70         struct resolv_query *ipv6_query;
  71
  72         guint ipv4_status;
  73         guint ipv6_status;
  74
  75         GResolvResultFunc result_func;
  76         gpointer result_data;
  77 };
  78
  79 struct resolv_query {
  80         GResolv *resolv;
  81
  82         guint timeout;
  83
  84         uint16_t msgid;
  85
  86         struct resolv_lookup *lookup;
  87 };
  88
  89 struct resolv_nameserver {
  90         GResolv *resolv;
  91
  92         char *address;
  93         uint16_t port;
  94         unsigned long flags;
  95
  96         GIOChannel *udp_channel;
  97         guint udp_watch;
  98 };
  99
 100 struct _GResolv {
 101         int ref_count;
 102
 103         int result_family;
 104
 105         guint next_lookup_id;
 106         GQueue *lookup_queue;
 107         GQueue *query_queue;
 108
 109         int index;
 110         GList *nameserver_list;
 111
 112         struct __res_state res;
 113
 114         GResolvDebugFunc debug_func;
 115         gpointer debug_data;
 116 };
 117
 118 static inline void debug(GResolv *resolv, const char *format, ...)
 119 {
 120         char str[256];
 121         va_list ap;
 122
 123         if (resolv->debug_func == NULL)
 124                 return;
 125
 126         va_start(ap, format);
 127
 128         if (vsnprintf(str, sizeof(str), format, ap) > 0)
 129                 resolv->debug_func(str, resolv->debug_data);
 130
 131         va_end(ap);
 132 }
 133
 134 static void destroy_query(struct resolv_query *query)
 135 {
 136         if (query->timeout > 0)
 137                 g_source_remove(query->timeout);
 138
 139         g_free(query);
 140 }
 141
 142 static void destroy_lookup(struct resolv_lookup *lookup)
 143 {
 144         if (lookup->ipv4_query != NULL) {
 145                 g_queue_remove(lookup->resolv->query_queue,
 146                                                 lookup->ipv4_query);
 147                 destroy_query(lookup->ipv4_query);
 148         }
 149
 150         if (lookup->ipv6_query != NULL) {
 151                 g_queue_remove(lookup->resolv->query_queue,
 152                                                 lookup->ipv6_query);
 153                 destroy_query(lookup->ipv6_query);
 154         }
 155
 156         g_free(lookup->results);
 157         g_free(lookup);
 158 }
 159
 160 static void find_srcaddr(struct sort_result *res)
 161 {
 162         socklen_t sl = sizeof(res->src);
 163         int fd;
 164
 165         fd = socket(res->dst.sa.sa_family, SOCK_DGRAM | SOCK_CLOEXEC,
 166                         IPPROTO_IP);
 167         if (fd < 0)
 168                 return;
 169
 170         if (connect(fd, &res->dst.sa, sizeof(res->dst)) < 0) {
 171                 close(fd);
 172                 return;
 173         }
 174
 175         if (getsockname(fd, &res->src.sa, &sl) < 0) {
 176                 close(fd);
 177                 return;
 178         }
 179
 180         res->reachable = TRUE;
 181         close(fd);
 182 }
 183
 184 struct gai_table
 185 {
 186         unsigned char addr[NS_IN6ADDRSZ];
 187         int mask;
 188         int value;
 189 };
 190
 191 static const struct gai_table gai_labels[] = {
 192         {
 193                 .addr = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 194                           0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01 },
 195                 .mask = 128,
 196                 .value = 0,
 197         }, {
 198                 .addr = { 0x20, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 199                           0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
 200                 .mask = 16,
 201                 .value = 2,
 202         }, {
 203                 .addr = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 204                           0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
 205                 .mask = 96,
 206                 .value = 3,
 207         }, {
 208                 .addr = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 209                           0x00, 0x00, 0xff, 0xff, 0x00, 0x00, 0x00, 0x00 },
 210                 .mask = 96,
 211                 .value = 4,
 212         }, {
 213                 /* Variations from RFC 3484, matching glibc behaviour */
 214                 .addr = { 0xfe, 0xc0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 215                           0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
 216                 .mask = 10,
 217                 .value = 5,
 218         }, {
 219                 .addr = { 0xfc, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 220                           0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
 221                 .mask = 7,
 222                 .value = 6,
 223         }, {
 224                 .addr = { 0x20, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 225                           0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
 226                 .mask = 32,
 227                 .value = 7,
 228         }, {
 229                 /* catch-all */
 230                 .addr = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 231                           0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
 232                 .mask = 0,
 233                 .value = 1,
 234         }
 235 };
 236
 237 static const struct gai_table gai_precedences[] = {
 238         {
 239                 .addr = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 240                           0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01 },
 241                 .mask = 128,
 242                 .value = 50,
 243         }, {
 244                 .addr = { 0x20, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 245                           0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
 246                 .mask = 16,
 247                 .value = 30,
 248         }, {
 249                 .addr = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 250                           0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
 251                 .mask = 96,
 252                 .value = 20,
 253         }, {
 254                 .addr = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 255                           0x00, 0x00, 0xff, 0xff, 0x00, 0x00, 0x00, 0x00 },
 256                 .mask = 96,
 257                 .value = 10,
 258         }, {
 259                 .addr = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 260                           0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
 261                 .mask = 0,
 262                 .value = 40,
 263         }
 264 };
 265
 266 static unsigned char v4mapped[] = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
 267                                     0x00, 0x00, 0xff, 0xff, 0x00, 0x00, 0x00, 0x00 };
 268
 269 static gboolean mask_compare(const unsigned char *one,
 270                                         const unsigned char *two, int mask)
 271 {
 272         if (mask > 8) {
 273                 if (memcmp(one, two, mask / 8))
 274                         return FALSE;
 275                 one += mask / 8;
 276                 two += mask / 8;
 277                 mask %= 8;
 278         }
 279
 280         if (mask && ((*one ^ *two) >> (8 - mask)))
 281                 return FALSE;
 282
 283         return TRUE;
 284 }
 285
 286 static int match_gai_table(struct sockaddr *sa, const struct gai_table *tbl)
 287 {
 288         struct sockaddr_in *sin = (void *)sa;
 289         struct sockaddr_in6 *sin6 = (void *)sa;
 290         void *addr;
 291
 292         if (sa->sa_family == AF_INET) {
 293                 addr = v4mapped;
 294                 memcpy(v4mapped+12, &sin->sin_addr, NS_INADDRSZ);
 295         } else
 296                 addr = &sin6->sin6_addr;
 297
 298         while (1) {
 299                 if (mask_compare(addr, tbl->addr, tbl->mask))
 300                         return tbl->value;
 301                 tbl++;
 302         }
 303 }
 304
 305 #define DQUAD(_a,_b,_c,_d) ( ((_a)<<24) | ((_b)<<16) | ((_c)<<8) | (_d) )
 306 #define V4MATCH(addr, a,b,c,d, m) ( ((addr) ^ DQUAD(a,b,c,d)) >> (32 - (m)) )
 307
 308 #define RFC3484_SCOPE_LINK      2
 309 #define RFC3484_SCOPE_SITE      5
 310 #define RFC3484_SCOPE_GLOBAL    14
 311
 312 static int addr_scope(struct sockaddr *sa)
 313 {
 314         if (sa->sa_family == AF_INET) {
 315                 struct sockaddr_in *sin = (void *)sa;
 316                 guint32 addr = ntohl(sin->sin_addr.s_addr);
 317
 318                 if (V4MATCH(addr, 169,254,0,0, 16) ||
 319                                         V4MATCH(addr, 127,0,0,0, 8))
 320                         return RFC3484_SCOPE_LINK;
 321
 322                 /* Site-local */
 323                 if (V4MATCH(addr, 10,0,0,0, 8) ||
 324                                 V4MATCH(addr, 172,16,0,0, 12) ||
 325                                 V4MATCH(addr, 192,168,0,0, 16))
 326                         return RFC3484_SCOPE_SITE;
 327
 328                 /* Global */
 329                 return RFC3484_SCOPE_GLOBAL;
 330         } else {
 331                 struct sockaddr_in6 *sin6 = (void *)sa;
 332
 333                 /* Multicast addresses have a 4-bit scope field */
 334                 if (IN6_IS_ADDR_MULTICAST(&sin6->sin6_addr))
 335                         return sin6->sin6_addr.s6_addr[1] & 0xf;
 336
 337                 if (IN6_IS_ADDR_LINKLOCAL(&sin6->sin6_addr) ||
 338                                 IN6_IS_ADDR_LOOPBACK(&sin6->sin6_addr))
 339                         return RFC3484_SCOPE_LINK;
 340
 341                 if (IN6_IS_ADDR_SITELOCAL(&sin6->sin6_addr))
 342                         return RFC3484_SCOPE_SITE;
 343
 344                 return RFC3484_SCOPE_GLOBAL;
 345         }
 346 }
 347
 348 static int rfc3484_compare(const void *__one, const void *__two)
 349 {
 350         const struct sort_result *one = __one;
 351         const struct sort_result *two = __two;
 352
 353         /* Rule 1: Avoid unusable destinations */
 354         if (one->reachable && !two->reachable)
 355                 return -1;
 356         else if (two->reachable && !one->reachable)
 357                 return 1;
 358
 359         /* Rule 2: Prefer matching scope */
 360         if (one->dst_scope == one->src_scope &&
 361                                 two->dst_scope != two->src_scope)
 362                 return -1;
 363         else if (two->dst_scope == two->src_scope &&
 364                                 one->dst_scope != one->src_scope)
 365                 return 1;
 366
 367         /* Rule 3: Avoid deprecated addresses */
 368
 369         /* Rule 4: Prefer home addresses */
 370
 371         /* Rule 5: Prefer matching label */
 372         if (one->dst_label == one->src_label &&
 373                                 two->dst_label != two->src_label)
 374                 return -1;
 375         else if (two->dst_label == two->src_label &&
 376                                 one->dst_label != one->src_label)
 377                 return 1;
 378
 379         /* Rule 6: Prefer higher precedence */
 380         if (one->precedence > two->precedence)
 381                 return -1;
 382         else if (two->precedence > one->precedence)
 383                 return 1;
 384
 385         /* Rule 7: Prefer native transport */
 386
 387         /* Rule 8: Prefer smaller scope */
 388         if (one->dst_scope != two->dst_scope)
 389                 return one->dst_scope - two->dst_scope;
 390
 391         /* Rule 9: Use longest matching prefix */
 392         if (one->dst.sa.sa_family == AF_INET) {
 393                 /*
 394                  * Rule 9 is meaningless and counterproductive for Legacy IP
 395                  * unless perhaps we can tell that it's actually on the local
 396                  * subnet. But we don't (yet) have local interface config
 397                  * information, so do nothing here for Legacy IP for now.
 398                  */
 399         } else {
 400                 int i;
 401
 402                 for (i = 0; i < 4; i++) {
 403                         guint32 cmp_one, cmp_two;
 404
 405                         cmp_one = one->src.sin6.sin6_addr.s6_addr32[i] ^
 406                                         one->dst.sin6.sin6_addr.s6_addr32[i];
 407                         cmp_two = two->src.sin6.sin6_addr.s6_addr32[i] ^
 408                                         two->dst.sin6.sin6_addr.s6_addr32[i];
 409
 410                         if (!cmp_two && !cmp_one)
 411                                 continue;
 412
 413                         if (cmp_one && !cmp_two)
 414                                 return 1;
 415                         if (cmp_two && !cmp_one)
 416                                 return -1;
 417
 418                         /* g_bit_storage() is effectively fls() */
 419                         cmp_one = g_bit_storage(ntohl(cmp_one));
 420                         cmp_two = g_bit_storage(ntohl(cmp_two));
 421
 422                         if (cmp_one == cmp_two)
 423                                 break;
 424
 425                         return cmp_one - cmp_two;
 426                 }
 427         }
 428
 429
 430         /* Rule 10: Otherwise, leave the order unchanged */
 431         if (one < two)
 432                 return -1;
 433         else
 434                 return 1;
 435 }
 436
 437 static void rfc3484_sort_results(struct resolv_lookup *lookup)
 438 {
 439         int i;
 440
 441         for (i = 0; i < lookup->nr_results; i++) {
 442                 struct sort_result *res = &lookup->results[i];
 443                 find_srcaddr(res);
 444                 res->precedence = match_gai_table(&res->dst.sa,
 445                                                         gai_precedences);
 446                 res->dst_label = match_gai_table(&res->dst.sa, gai_labels);
 447                 res->src_label = match_gai_table(&res->src.sa, gai_labels);
 448                 res->dst_scope = addr_scope(&res->dst.sa);
 449                 res->src_scope = addr_scope(&res->src.sa);
 450         }
 451
 452         qsort(lookup->results, lookup->nr_results,
 453                         sizeof(struct sort_result), rfc3484_compare);
 454 }
 455
 456 static void sort_and_return_results(struct resolv_lookup *lookup)
 457 {
 458         char buf[INET6_ADDRSTRLEN + 1];
 459         GResolvResultStatus status;
 460         char **results = g_try_new0(char *, lookup->nr_results + 1);
 461         int i, n = 0;
 462
 463         if (!results)
 464                 return;
 465
 466         memset(buf, 0, INET6_ADDRSTRLEN + 1);
 467
 468         rfc3484_sort_results(lookup);
 469
 470         for (i = 0; i < lookup->nr_results; i++) {
 471                 if (lookup->results[i].dst.sa.sa_family == AF_INET) {
 472                         if (inet_ntop(AF_INET,
 473                                         &lookup->results[i].dst.sin.sin_addr,
 474                                         buf, sizeof(buf) - 1) == NULL)
 475                                 continue;
 476                 } else if (lookup->results[i].dst.sa.sa_family == AF_INET6) {
 477                         if (inet_ntop(AF_INET6,
 478                                         &lookup->results[i].dst.sin6.sin6_addr,
 479                                         buf, sizeof(buf) - 1) == NULL)
 480                                 continue;
 481                 } else
 482                         continue;
 483
 484                 results[n++] = strdup(buf);
 485         }
 486
 487         results[n++] = NULL;
 488
 489         status = lookup->ipv4_status;
 490
 491         if (status == G_RESOLV_RESULT_STATUS_SUCCESS)
 492                 status = lookup->ipv6_status;
 493
 494         lookup->result_func(status, results, lookup->result_data);
 495
 496         g_strfreev(results);
 497         g_queue_remove(lookup->resolv->lookup_queue, lookup);
 498         destroy_lookup(lookup);
 499 }
 500
 501 static gboolean query_timeout(gpointer user_data)
 502 {
 503         struct resolv_query *query = user_data;
 504         struct resolv_lookup *lookup = query->lookup;
 505         GResolv *resolv = query->resolv;
 506
 507         query->timeout = 0;
 508
 509         if (query == lookup->ipv4_query) {
 510                 lookup->ipv4_status = G_RESOLV_RESULT_STATUS_NO_RESPONSE;
 511                 lookup->ipv4_query = NULL;
 512         } else if (query == lookup->ipv6_query) {
 513                 lookup->ipv6_status = G_RESOLV_RESULT_STATUS_NO_RESPONSE;
 514                 lookup->ipv6_query = NULL;
 515         }
 516
 517         if (lookup->ipv4_query == NULL && lookup->ipv4_query == NULL)
 518                 sort_and_return_results(lookup);
 519
 520         destroy_query(query);
 521         g_queue_remove(resolv->query_queue, query);
 522
 523         return FALSE;
 524 }
 525
 526 static void free_nameserver(struct resolv_nameserver *nameserver)
 527 {
 528         if (nameserver == NULL)
 529                 return;
 530
 531         if (nameserver->udp_watch > 0)
 532                 g_source_remove(nameserver->udp_watch);
 533
 534         if (nameserver->udp_channel != NULL)
 535                 g_io_channel_unref(nameserver->udp_channel);
 536
 537         g_free(nameserver->address);
 538         g_free(nameserver);
 539 }
 540
 541 static void flush_nameservers(GResolv *resolv)
 542 {
 543         GList *list;
 544
 545         for (list = g_list_first(resolv->nameserver_list);
 546                                         list; list = g_list_next(list))
 547                 free_nameserver(list->data);
 548
 549         g_list_free(resolv->nameserver_list);
 550         resolv->nameserver_list = NULL;
 551 }
 552
 553 static int send_query(GResolv *resolv, const unsigned char *buf, int len)
 554 {
 555         GList *list;
 556
 557         if (resolv->nameserver_list == NULL)
 558                 return -ENOENT;
 559
 560         for (list = g_list_first(resolv->nameserver_list);
 561                                         list; list = g_list_next(list)) {
 562                 struct resolv_nameserver *nameserver = list->data;
 563                 int sk, sent;
 564
 565                 if (nameserver->udp_channel == NULL)
 566                         continue;
 567
 568                 sk = g_io_channel_unix_get_fd(nameserver->udp_channel);
 569
 570                 sent = send(sk, buf, len, 0);
 571                 if (sent < 0)
 572                         continue;
 573         }
 574
 575         return 0;
 576 }
 577
 578 static gint compare_lookup_id(gconstpointer a, gconstpointer b)
 579 {
 580         const struct resolv_lookup *lookup = a;
 581         guint id = GPOINTER_TO_UINT(b);
 582
 583         if (lookup->id < id)
 584                 return -1;
 585
 586         if (lookup->id > id)
 587                 return 1;
 588
 589         return 0;
 590 }
 591
 592 static gint compare_query_msgid(gconstpointer a, gconstpointer b)
 593 {
 594         const struct resolv_query *query = a;
 595         uint16_t msgid = GPOINTER_TO_UINT(b);
 596
 597         if (query->msgid < msgid)
 598                 return -1;
 599
 600         if (query->msgid > msgid)
 601                 return 1;
 602
 603         return 0;
 604 }
 605
 606 static void add_result(struct resolv_lookup *lookup, int family,
 607                                                         const void *data)
 608 {
 609         int n = lookup->nr_results++;
 610         lookup->results = g_realloc(lookup->results,
 611                                         sizeof(struct sort_result) * (n + 1));
 612
 613         memset(&lookup->results[n], 0, sizeof(struct sort_result));
 614
 615         lookup->results[n].dst.sa.sa_family = family;
 616         if (family == AF_INET)
 617                 memcpy(&lookup->results[n].dst.sin.sin_addr,
 618                                                 data, NS_INADDRSZ);
 619         else
 620                 memcpy(&lookup->results[n].dst.sin6.sin6_addr,
 621                                                 data, NS_IN6ADDRSZ);
 622 }
 623
 624 static void parse_response(struct resolv_nameserver *nameserver,
 625                                         const unsigned char *buf, int len)
 626 {
 627         GResolv *resolv = nameserver->resolv;
 628         GResolvResultStatus status;
 629         struct resolv_query *query;
 630         struct resolv_lookup *lookup;
 631         GList *list;
 632         ns_msg msg;
 633         ns_rr rr;
 634         int i, rcode, count;
 635
 636         debug(resolv, "response from %s", nameserver->address);
 637
 638         ns_initparse(buf, len, &msg);
 639
 640         rcode = ns_msg_getflag(msg, ns_f_rcode);
 641         count = ns_msg_count(msg, ns_s_an);
 642
 643         debug(resolv, "msg id: 0x%04x rcode: %d count: %d",
 644                                         ns_msg_id(msg), rcode, count);
 645
 646         switch (rcode) {
 647         case 0:
 648                 status = G_RESOLV_RESULT_STATUS_SUCCESS;
 649                 break;
 650         case 1:
 651                 status = G_RESOLV_RESULT_STATUS_FORMAT_ERROR;
 652                 break;
 653         case 2:
 654                 status = G_RESOLV_RESULT_STATUS_SERVER_FAILURE;
 655                 break;
 656         case 3:
 657                 status = G_RESOLV_RESULT_STATUS_NAME_ERROR;
 658                 break;
 659         case 4:
 660                 status = G_RESOLV_RESULT_STATUS_NOT_IMPLEMENTED;
 661                 break;
 662         case 5:
 663                 status = G_RESOLV_RESULT_STATUS_REFUSED;
 664                 break;
 665         default:
 666                 status = G_RESOLV_RESULT_STATUS_ERROR;
 667                 break;
 668         }
 669
 670         list = g_queue_find_custom(resolv->query_queue,
 671                         GUINT_TO_POINTER(ns_msg_id(msg)), compare_query_msgid);
 672         if (!list)
 673                 return;
 674
 675         query = list->data;
 676         lookup = query->lookup;
 677
 678         if (query == lookup->ipv6_query) {
 679                 lookup->ipv6_status = status;
 680                 lookup->ipv6_query = NULL;
 681         } else if (query == lookup->ipv4_query) {
 682                 lookup->ipv4_status = status;
 683                 lookup->ipv4_query = NULL;
 684         }
 685
 686         for (i = 0; i < count; i++) {
 687                 ns_parserr(&msg, ns_s_an, i, &rr);
 688
 689                 if (ns_rr_class(rr) != ns_c_in)
 690                         continue;
 691
 692                 g_assert(offsetof(struct sockaddr_in, sin_addr) ==
 693                                 offsetof(struct sockaddr_in6, sin6_flowinfo));
 694
 695                 if (ns_rr_type(rr) == ns_t_a &&
 696                                         ns_rr_rdlen(rr) == NS_INADDRSZ) {
 697                         add_result(lookup, AF_INET, ns_rr_rdata(rr));
 698                 } else if (ns_rr_type(rr) == ns_t_aaaa &&
 699                                         ns_rr_rdlen(rr) == NS_IN6ADDRSZ) {
 700                         add_result(lookup, AF_INET6, ns_rr_rdata(rr));
 701                 }
 702         }
 703
 704         if (lookup->ipv4_query == NULL && lookup->ipv6_query == NULL)
 705                 sort_and_return_results(lookup);
 706
 707         destroy_query(query);
 708         g_queue_remove(resolv->query_queue, query);
 709 }
 710
 711 static gboolean received_udp_data(GIOChannel *channel, GIOCondition cond,
 712                                                         gpointer user_data)
 713 {
 714         struct resolv_nameserver *nameserver = user_data;
 715         unsigned char buf[4096];
 716         int sk, len;
 717
 718         if (cond & (G_IO_NVAL | G_IO_ERR | G_IO_HUP)) {
 719                 nameserver->udp_watch = 0;
 720                 return FALSE;
 721         }
 722
 723         sk = g_io_channel_unix_get_fd(nameserver->udp_channel);
 724
 725         len = recv(sk, buf, sizeof(buf), 0);
 726         if (len < 12)
 727                 return TRUE;
 728
 729         parse_response(nameserver, buf, len);
 730
 731         return TRUE;
 732 }
 733
 734 static int connect_udp_channel(struct resolv_nameserver *nameserver)
 735 {
 736         struct addrinfo hints, *rp;
 737         char portnr[6];
 738         int err, sk;
 739
 740         memset(&hints, 0, sizeof(hints));
 741         hints.ai_family = AF_UNSPEC;
 742         hints.ai_socktype = SOCK_DGRAM;
 743         hints.ai_flags = AI_PASSIVE | AI_NUMERICSERV | AI_NUMERICHOST;
 744
 745         sprintf(portnr, "%d", nameserver->port);
 746         err = getaddrinfo(nameserver->address, portnr, &hints, &rp);
 747         if (err)
 748                 return -EINVAL;
 749
 750         /*
 751          * Do not blindly copy this code elsewhere; it doesn't loop over the
 752          * results using ->ai_next as it should. That's OK in *this* case
 753          * because it was a numeric lookup; we *know* there's only one.
 754          */
 755         if (!rp)
 756                 return -EINVAL;
 757
 758         sk = socket(rp->ai_family, rp->ai_socktype, rp->ai_protocol);
 759         if (sk < 0) {
 760                 freeaddrinfo(rp);
 761                 return -EIO;
 762         }
 763
 764         /*
 765          * If nameserver points to localhost ip, their is no need to
 766          * bind the socket on any interface.
 767          */
 768         if (nameserver->resolv->index > 0 &&
 769                         strncmp(nameserver->address, "127.0.0.1", 9) != 0) {
 770                 char interface[IF_NAMESIZE];
 771
 772                 memset(interface, 0, IF_NAMESIZE);
 773                 if (if_indextoname(nameserver->resolv->index,
 774                                                 interface) != NULL) {
 775                         if (setsockopt(sk, SOL_SOCKET, SO_BINDTODEVICE,
 776                                                 interface, IF_NAMESIZE) < 0) {
 777                                 close(sk);
 778                                 freeaddrinfo(rp);
 779                                 return -EIO;
 780                         }
 781                 }
 782         }
 783
 784         if (connect(sk, rp->ai_addr, rp->ai_addrlen) < 0) {
 785                 close(sk);
 786                 freeaddrinfo(rp);
 787                 return -EIO;
 788         }
 789
 790         freeaddrinfo(rp);
 791
 792         nameserver->udp_channel = g_io_channel_unix_new(sk);
 793         if (nameserver->udp_channel == NULL) {
 794                 close(sk);
 795                 return -ENOMEM;
 796         }
 797
 798         g_io_channel_set_close_on_unref(nameserver->udp_channel, TRUE);
 799
 800         nameserver->udp_watch = g_io_add_watch(nameserver->udp_channel,
 801                                 G_IO_IN | G_IO_NVAL | G_IO_ERR | G_IO_HUP,
 802                                 received_udp_data, nameserver);
 803
 804         return 0;
 805 }
 806
 807 GResolv *g_resolv_new(int index)
 808 {
 809         GResolv *resolv;
 810
 811         if (index < 0)
 812                 return NULL;
 813
 814         resolv = g_try_new0(GResolv, 1);
 815         if (resolv == NULL)
 816                 return NULL;
 817
 818         resolv->ref_count = 1;
 819
 820         resolv->result_family = AF_UNSPEC;
 821
 822         resolv->next_lookup_id = 1;
 823
 824         resolv->query_queue = g_queue_new();
 825         if (resolv->query_queue == NULL) {
 826                 g_free(resolv);
 827                 return NULL;
 828         }
 829
 830         resolv->lookup_queue = g_queue_new();
 831         if (resolv->lookup_queue == NULL) {
 832                 g_queue_free(resolv->query_queue);
 833                 g_free(resolv);
 834                 return NULL;
 835         }
 836
 837         resolv->index = index;
 838         resolv->nameserver_list = NULL;
 839
 840         res_ninit(&resolv->res);
 841
 842         return resolv;
 843 }
 844
 845 GResolv *g_resolv_ref(GResolv *resolv)
 846 {
 847         if (resolv == NULL)
 848                 return NULL;
 849
 850         __sync_fetch_and_add(&resolv->ref_count, 1);
 851
 852         return resolv;
 853 }
 854
 855 void g_resolv_unref(GResolv *resolv)
 856 {
 857         struct resolv_query *query;
 858
 859         if (resolv == NULL)
 860                 return;
 861
 862         if (__sync_fetch_and_sub(&resolv->ref_count, 1) != 1)
 863                 return;
 864
 865         while ((query = g_queue_pop_head(resolv->query_queue)))
 866                 destroy_query(query);
 867
 868         g_queue_free(resolv->query_queue);
 869         g_queue_free(resolv->lookup_queue);
 870
 871         flush_nameservers(resolv);
 872
 873         res_nclose(&resolv->res);
 874
 875         g_free(resolv);
 876 }
 877
 878 void g_resolv_set_debug(GResolv *resolv, GResolvDebugFunc func,
 879                                                 gpointer user_data)
 880 {
 881         if (resolv == NULL)
 882                 return;
 883
 884         resolv->debug_func = func;
 885         resolv->debug_data = user_data;
 886 }
 887
 888 gboolean g_resolv_add_nameserver(GResolv *resolv, const char *address,
 889                                         uint16_t port, unsigned long flags)
 890 {
 891         struct resolv_nameserver *nameserver;
 892
 893         if (resolv == NULL)
 894                 return FALSE;
 895
 896         nameserver = g_try_new0(struct resolv_nameserver, 1);
 897         if (nameserver == NULL)
 898                 return FALSE;
 899
 900         nameserver->address = g_strdup(address);
 901         nameserver->port = port;
 902         nameserver->flags = flags;
 903         nameserver->resolv = resolv;
 904
 905         if (connect_udp_channel(nameserver) < 0) {
 906                 free_nameserver(nameserver);
 907                 return FALSE;
 908         }
 909
 910         resolv->nameserver_list = g_list_append(resolv->nameserver_list,
 911                                                                 nameserver);
 912
 913         debug(resolv, "setting nameserver %s", address);
 914
 915         return TRUE;
 916 }
 917
 918 void g_resolv_flush_nameservers(GResolv *resolv)
 919 {
 920         if (resolv == NULL)
 921                 return;
 922
 923         flush_nameservers(resolv);
 924 }
 925
 926 static gint add_query(struct resolv_lookup *lookup, const char *hostname, int type)
 927 {
 928         struct resolv_query *query = g_try_new0(struct resolv_query, 1);
 929         unsigned char buf[4096];
 930         int len;
 931
 932         if (query == NULL)
 933                 return -ENOMEM;
 934
 935         len = res_mkquery(ns_o_query, hostname, ns_c_in, type,
 936                                         NULL, 0, NULL, buf, sizeof(buf));
 937
 938         query->msgid = buf[0] << 8 | buf[1];
 939
 940         if (send_query(lookup->resolv, buf, len) < 0) {
 941                 g_free(query);
 942                 return -EIO;
 943         }
 944
 945         query->resolv = lookup->resolv;
 946         query->lookup = lookup;
 947
 948         g_queue_push_tail(lookup->resolv->query_queue, query);
 949
 950         query->timeout = g_timeout_add_seconds(5, query_timeout, query);
 951
 952         if (type == ns_t_aaaa)
 953                 lookup->ipv6_query = query;
 954         else
 955                 lookup->ipv4_query = query;
 956
 957         return 0;
 958 }
 959
 960 guint g_resolv_lookup_hostname(GResolv *resolv, const char *hostname,
 961                                 GResolvResultFunc func, gpointer user_data)
 962 {
 963         struct resolv_lookup *lookup;
 964
 965         debug(resolv, "lookup hostname %s", hostname);
 966
 967         if (resolv == NULL)
 968                 return 0;
 969
 970         if (resolv->nameserver_list == NULL) {
 971                 int i;
 972
 973                 for (i = 0; i < resolv->res.nscount; i++) {
 974                         char buf[100];
 975                         int family = resolv->res.nsaddr_list[i].sin_family;
 976                         void *sa_addr = &resolv->res.nsaddr_list[i].sin_addr;
 977
 978                         if (family != AF_INET &&
 979                                         resolv->res._u._ext.nsaddrs[i]) {
 980                                 family = AF_INET6;
 981                                 sa_addr = &resolv->res._u._ext.nsaddrs[i]->sin6_addr;
 982                         }
 983
 984                         if (family != AF_INET && family != AF_INET6)
 985                                 continue;
 986
 987                         if (inet_ntop(family, sa_addr, buf, sizeof(buf)))
 988                                 g_resolv_add_nameserver(resolv, buf, 53, 0);
 989                 }
 990
 991                 if (resolv->nameserver_list == NULL)
 992                         g_resolv_add_nameserver(resolv, "127.0.0.1", 53, 0);
 993         }
 994
 995         lookup = g_try_new0(struct resolv_lookup, 1);
 996         if (lookup == NULL)
 997                 return 0;
 998
 999         lookup->resolv = resolv;
1000         lookup->result_func = func;
1001         lookup->result_data = user_data;
1002         lookup->id = resolv->next_lookup_id++;
1003
1004         if (resolv->result_family != AF_INET6) {
1005                 if (add_query(lookup, hostname, ns_t_a)) {
1006                         g_free(lookup);
1007                         return -EIO;
1008                 }
1009         }
1010
1011         if (resolv->result_family != AF_INET) {
1012                 if (add_query(lookup, hostname, ns_t_aaaa)) {
1013                         if (resolv->result_family != AF_INET6) {
1014                                 destroy_query(lookup->ipv4_query);
1015                                 g_queue_remove(resolv->query_queue,
1016                                                 lookup->ipv4_query);
1017                         }
1018
1019                         g_free(lookup);
1020                         return -EIO;
1021                 }
1022         }
1023
1024         g_queue_push_tail(resolv->lookup_queue, lookup);
1025         return lookup->id;
1026 }
1027
1028 gboolean g_resolv_cancel_lookup(GResolv *resolv, guint id)
1029 {
1030         GList *list;
1031
1032         list = g_queue_find_custom(resolv->lookup_queue,
1033                                 GUINT_TO_POINTER(id), compare_lookup_id);
1034
1035         if (list == NULL)
1036                 return FALSE;
1037
1038         destroy_lookup(list->data);
1039         g_queue_remove(resolv->query_queue, list->data);
1040
1041         return TRUE;
1042 }
1043
1044 gboolean g_resolv_set_address_family(GResolv *resolv, int family)
1045 {
1046         if (resolv == NULL)
1047                 return FALSE;
1048
1049         if (family != AF_UNSPEC && family != AF_INET && family != AF_INET6)
1050                 return FALSE;
1051
1052         resolv->result_family = family;
1053
1054         return TRUE;
1055 }