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