src/dnsproxy.c

   1 /*
   2  *
   3  *  Connection Manager
   4  *
   5  *  Copyright (C) 2007-2010  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 <string.h>
  29 #include <stdint.h>
  30 #include <arpa/inet.h>
  31 #include <netinet/in.h>
  32 #include <sys/types.h>
  33 #include <sys/socket.h>
  34 #include <netdb.h>
  35 #include <resolv.h>
  36
  37 #include <glib.h>
  38
  39 #include "connman.h"
  40
  41 #if __BYTE_ORDER == __LITTLE_ENDIAN
  42 struct domain_hdr {
  43         uint16_t id;
  44         uint8_t rd:1;
  45         uint8_t tc:1;
  46         uint8_t aa:1;
  47         uint8_t opcode:4;
  48         uint8_t qr:1;
  49         uint8_t rcode:4;
  50         uint8_t z:3;
  51         uint8_t ra:1;
  52         uint16_t qdcount;
  53         uint16_t ancount;
  54         uint16_t nscount;
  55         uint16_t arcount;
  56 } __attribute__ ((packed));
  57 #elif __BYTE_ORDER == __BIG_ENDIAN
  58 struct domain_hdr {
  59         uint16_t id;
  60         uint8_t qr:1;
  61         uint8_t opcode:4;
  62         uint8_t aa:1;
  63         uint8_t tc:1;
  64         uint8_t rd:1;
  65         uint8_t ra:1;
  66         uint8_t z:3;
  67         uint8_t rcode:4;
  68         uint16_t qdcount;
  69         uint16_t ancount;
  70         uint16_t nscount;
  71         uint16_t arcount;
  72 } __attribute__ ((packed));
  73 #else
  74 #error "Unknown byte order"
  75 #endif
  76
  77 struct partial_reply {
  78         uint16_t len;
  79         uint16_t received;
  80         unsigned char buf[];
  81 };
  82
  83 struct server_data {
  84         char *interface;
  85         GList *domains;
  86         char *server;
  87         int protocol;
  88         GIOChannel *channel;
  89         guint watch;
  90         guint timeout;
  91         gboolean enabled;
  92         gboolean connected;
  93         struct partial_reply *incoming_reply;
  94 };
  95
  96 struct request_data {
  97         union {
  98                 struct sockaddr_in6 __sin6; /* Only for the length */
  99                 struct sockaddr sa;
 100         };
 101         socklen_t sa_len;
 102         int client_sk;
 103         int protocol;
 104         guint16 srcid;
 105         guint16 dstid;
 106         guint16 altid;
 107         guint timeout;
 108         guint watch;
 109         guint numserv;
 110         guint numresp;
 111         gpointer request;
 112         gsize request_len;
 113         gpointer name;
 114         gpointer resp;
 115         gsize resplen;
 116         struct listener_data *ifdata;
 117         gboolean append_domain;
 118 };
 119
 120 struct listener_data {
 121         char *ifname;
 122         GIOChannel *udp_listener_channel;
 123         guint udp_listener_watch;
 124         GIOChannel *tcp_listener_channel;
 125         guint tcp_listener_watch;
 126 };
 127
 128 struct cache_data {
 129         time_t inserted;
 130         int timeout;
 131         uint16_t type;
 132         uint16_t answers;
 133         unsigned int data_len;
 134         unsigned char *data; /* contains DNS header + body */
 135 };
 136
 137 struct cache_entry {
 138         char *key;
 139         struct cache_data *ipv4;
 140         struct cache_data *ipv6;
 141 };
 142
 143 struct domain_question {
 144         uint16_t type;
 145         uint16_t class;
 146 } __attribute__ ((packed));
 147
 148 struct domain_rr {
 149         uint16_t type;
 150         uint16_t class;
 151         uint32_t ttl;
 152         uint16_t rdlen;
 153 } __attribute__ ((packed));
 154
 155 /*
 156  * We limit how long the cached DNS entry stays in the cache.
 157  * By default the TTL (time-to-live) of the DNS response is used
 158  * when setting the cache entry life time. The value is in seconds.
 159  */
 160 #define MAX_CACHE_TTL (60 * 30)
 161
 162 /*
 163  * We limit the cache size to some sane value so that cached data does
 164  * not occupy too much memory. Each cached entry occupies on average
 165  * about 100 bytes memory (depending on DNS name length).
 166  * Example: caching www.connman.net uses 97 bytes memory.
 167  * The value is the max amount of cached DNS responses (count).
 168  */
 169 #define MAX_CACHE_SIZE 256
 170
 171 static int cache_size;
 172 static GHashTable *cache;
 173 static int cache_refcount;
 174 static GSList *server_list = NULL;
 175 static GSList *request_list = NULL;
 176 static GSList *request_pending_list = NULL;
 177 static guint16 request_id = 0x0000;
 178 static GHashTable *listener_table = NULL;
 179
 180 static int protocol_offset(int protocol)
 181 {
 182         switch (protocol) {
 183         case IPPROTO_UDP:
 184                 return 0;
 185
 186         case IPPROTO_TCP:
 187                 return 2;
 188
 189         default:
 190                 return -EINVAL;
 191         }
 192
 193 }
 194
 195 static struct request_data *find_request(guint16 id)
 196 {
 197         GSList *list;
 198
 199         for (list = request_list; list; list = list->next) {
 200                 struct request_data *req = list->data;
 201
 202                 if (req->dstid == id || req->altid == id)
 203                         return req;
 204         }
 205
 206         return NULL;
 207 }
 208
 209 static struct server_data *find_server(const char *interface,
 210                                         const char *server,
 211                                                 int protocol)
 212 {
 213         GSList *list;
 214
 215         DBG("interface %s server %s", interface, server);
 216
 217         for (list = server_list; list; list = list->next) {
 218                 struct server_data *data = list->data;
 219
 220                 if (interface == NULL && data->interface == NULL &&
 221                                 g_str_equal(data->server, server) == TRUE &&
 222                                 data->protocol == protocol)
 223                         return data;
 224
 225                 if (interface == NULL ||
 226                                 data->interface == NULL || data->server == NULL)
 227                         continue;
 228
 229                 if (g_str_equal(data->interface, interface) == TRUE &&
 230                                 g_str_equal(data->server, server) == TRUE &&
 231                                 data->protocol == protocol)
 232                         return data;
 233         }
 234
 235         return NULL;
 236 }
 237
 238 static void send_cached_response(int sk, unsigned char *buf, int len,
 239                                 const struct sockaddr *to, socklen_t tolen,
 240                                 int protocol, int id, uint16_t answers)
 241 {
 242         struct domain_hdr *hdr;
 243         int err, offset = protocol_offset(protocol);
 244
 245         if (offset < 0)
 246                 return;
 247
 248         if (len < 12)
 249                 return;
 250
 251         hdr = (void *) (buf + offset);
 252
 253         hdr->id = id;
 254         hdr->qr = 1;
 255         hdr->rcode = 0;
 256         hdr->ancount = htons(answers);
 257         hdr->nscount = 0;
 258         hdr->arcount = 0;
 259
 260         DBG("id 0x%04x answers %d", hdr->id, answers);
 261
 262         err = sendto(sk, buf, len, 0, to, tolen);
 263         if (err < 0) {
 264                 connman_error("Cannot send cached DNS response: %s",
 265                                 strerror(errno));
 266                 return;
 267         }
 268 }
 269
 270 static void send_response(int sk, unsigned char *buf, int len,
 271                                 const struct sockaddr *to, socklen_t tolen,
 272                                 int protocol)
 273 {
 274         struct domain_hdr *hdr;
 275         int err, offset = protocol_offset(protocol);
 276
 277         DBG("");
 278
 279         if (offset < 0)
 280                 return;
 281
 282         if (len < 12)
 283                 return;
 284
 285         hdr = (void *) (buf + offset);
 286
 287         DBG("id 0x%04x qr %d opcode %d", hdr->id, hdr->qr, hdr->opcode);
 288
 289         hdr->qr = 1;
 290         hdr->rcode = 2;
 291
 292         hdr->ancount = 0;
 293         hdr->nscount = 0;
 294         hdr->arcount = 0;
 295
 296         err = sendto(sk, buf, len, 0, to, tolen);
 297         if (err < 0) {
 298                 connman_error("Failed to send DNS response: %s",
 299                                 strerror(errno));
 300                 return;
 301         }
 302 }
 303
 304 static gboolean request_timeout(gpointer user_data)
 305 {
 306         struct request_data *req = user_data;
 307         struct listener_data *ifdata;
 308
 309         DBG("id 0x%04x", req->srcid);
 310
 311         if (req == NULL)
 312                 return FALSE;
 313
 314         ifdata = req->ifdata;
 315
 316         request_list = g_slist_remove(request_list, req);
 317         req->numserv--;
 318
 319         if (req->resplen > 0 && req->resp != NULL) {
 320                 int sk, err;
 321
 322                 sk = g_io_channel_unix_get_fd(ifdata->udp_listener_channel);
 323
 324                 err = sendto(sk, req->resp, req->resplen, 0,
 325                                                 &req->sa, req->sa_len);
 326                 if (err < 0)
 327                         return FALSE;
 328         } else if (req->request && req->numserv == 0) {
 329                 struct domain_hdr *hdr;
 330
 331                 if (req->protocol == IPPROTO_TCP) {
 332                         hdr = (void *) (req->request + 2);
 333                         hdr->id = req->srcid;
 334                         send_response(req->client_sk, req->request,
 335                                 req->request_len, NULL, 0, IPPROTO_TCP);
 336
 337                 } else if (req->protocol == IPPROTO_UDP) {
 338                         int sk;
 339
 340                         hdr = (void *) (req->request);
 341                         hdr->id = req->srcid;
 342                         sk = g_io_channel_unix_get_fd(
 343                                                 ifdata->udp_listener_channel);
 344                         send_response(sk, req->request, req->request_len,
 345                                         &req->sa, req->sa_len, IPPROTO_UDP);
 346                 }
 347         }
 348
 349         g_free(req->resp);
 350         g_free(req);
 351
 352         return FALSE;
 353 }
 354
 355 static int append_query(unsigned char *buf, unsigned int size,
 356                                 const char *query, const char *domain)
 357 {
 358         unsigned char *ptr = buf;
 359         char *offset;
 360         int len;
 361
 362         DBG("query %s domain %s", query, domain);
 363
 364         offset = (char *) query;
 365         while (offset != NULL) {
 366                 char *tmp;
 367
 368                 tmp = strchr(offset, '.');
 369                 if (tmp == NULL) {
 370                         len = strlen(offset);
 371                         if (len == 0)
 372                                 break;
 373                         *ptr = len;
 374                         memcpy(ptr + 1, offset, len);
 375                         ptr += len + 1;
 376                         break;
 377                 }
 378
 379                 *ptr = tmp - offset;
 380                 memcpy(ptr + 1, offset, tmp - offset);
 381                 ptr += tmp - offset + 1;
 382
 383                 offset = tmp + 1;
 384         }
 385
 386         offset = (char *) domain;
 387         while (offset != NULL) {
 388                 char *tmp;
 389
 390                 tmp = strchr(offset, '.');
 391                 if (tmp == NULL) {
 392                         len = strlen(offset);
 393                         if (len == 0)
 394                                 break;
 395                         *ptr = len;
 396                         memcpy(ptr + 1, offset, len);
 397                         ptr += len + 1;
 398                         break;
 399                 }
 400
 401                 *ptr = tmp - offset;
 402                 memcpy(ptr + 1, offset, tmp - offset);
 403                 ptr += tmp - offset + 1;
 404
 405                 offset = tmp + 1;
 406         }
 407
 408         *ptr++ = 0x00;
 409
 410         return ptr - buf;
 411 }
 412
 413 static gboolean cache_check_is_valid(struct cache_data *data,
 414                                 time_t current_time)
 415 {
 416         if (data == NULL)
 417                 return FALSE;
 418
 419         if (data->inserted + data->timeout < current_time)
 420                 return FALSE;
 421
 422         return TRUE;
 423 }
 424
 425 static uint16_t cache_check_validity(char *question, uint16_t type,
 426                                 struct cache_data *ipv4,
 427                                 struct cache_data *ipv6)
 428 {
 429         time_t current_time = time(0);
 430
 431         switch (type) {
 432         case 1:         /* IPv4 */
 433                 if (cache_check_is_valid(ipv4, current_time) == FALSE) {
 434                         DBG("cache %s \"%s\" type A",
 435                                 ipv4 ? "timeout" : "entry missing", question);
 436
 437                         /*
 438                          * We do not remove cache entry if there is still
 439                          * valid IPv6 entry found in the cache.
 440                          */
 441                         if (cache_check_is_valid(ipv6, current_time) == FALSE)
 442                                 g_hash_table_remove(cache, question);
 443
 444                         type = 0;
 445                 }
 446                 break;
 447
 448         case 28:        /* IPv6 */
 449                 if (cache_check_is_valid(ipv6, current_time) == FALSE) {
 450                         DBG("cache %s \"%s\" type AAAA",
 451                                 ipv6 ? "timeout" : "entry missing", question);
 452
 453                         if (cache_check_is_valid(ipv4, current_time) == FALSE)
 454                                 g_hash_table_remove(cache, question);
 455
 456                         type = 0;
 457                 }
 458                 break;
 459         }
 460
 461         return type;
 462 }
 463
 464 static struct cache_entry *cache_check(gpointer request, int *qtype)
 465 {
 466         char *question = request + 12;
 467         struct cache_entry *entry;
 468         struct domain_question *q;
 469         uint16_t type;
 470         int offset;
 471
 472         offset = strlen(question) + 1;
 473         q = (void *) (question + offset);
 474         type = ntohs(q->type);
 475
 476         /* We only cache either A (1) or AAAA (28) requests */
 477         if (type != 1 && type != 28)
 478                 return NULL;
 479
 480         entry = g_hash_table_lookup(cache, question);
 481         if (entry == NULL)
 482                 return NULL;
 483
 484         type = cache_check_validity(question, type, entry->ipv4, entry->ipv6);
 485         if (type == 0)
 486                 return NULL;
 487
 488         *qtype = type;
 489         return entry;
 490 }
 491
 492 /*
 493  * Get a label/name from DNS resource record. The function decompresses the
 494  * label if necessary. The function does not convert the name to presentation
 495  * form. This means that the result string will contain label lengths instead
 496  * of dots between labels. We intentionally do not want to convert to dotted
 497  * format so that we can cache the wire format string directly.
 498  */
 499 static int get_name(int counter,
 500                 unsigned char *pkt, unsigned char *start, unsigned char *max,
 501                 unsigned char *output, int output_max, int *output_len,
 502                 unsigned char **end, char *name, int *name_len)
 503 {
 504         unsigned char *p;
 505
 506         /* Limit recursion to 10 (this means up to 10 labels in domain name) */
 507         if (counter > 10)
 508                 return -EINVAL;
 509
 510         p = start;
 511         while (*p) {
 512                 if ((*p & NS_CMPRSFLGS) == NS_CMPRSFLGS) {
 513                         uint16_t offset = (*p & 0x3F) * 256 + *(p + 1);
 514
 515                         if (offset >= max - pkt)
 516                                 return -ENOBUFS;
 517
 518                         if (*end == NULL)
 519                                 *end = p + 2;
 520
 521                         return get_name(counter + 1, pkt, pkt + offset, max,
 522                                         output, output_max, output_len, end,
 523                                         name, name_len);
 524                 } else {
 525                         unsigned label_len = *p;
 526
 527                         if (pkt + label_len > max)
 528                                 return -ENOBUFS;
 529
 530                         if (*output_len > output_max)
 531                                 return -ENOBUFS;
 532
 533                         /*
 534                          * We need the original name in order to check
 535                          * if this answer is the correct one.
 536                          */
 537                         name[(*name_len)++] = label_len;
 538                         memcpy(name + *name_len, p + 1, label_len + 1);
 539                         *name_len += label_len;
 540
 541                         /* We compress the result */
 542                         output[0] = NS_CMPRSFLGS;
 543                         output[1] = 0x0C;
 544                         *output_len = 2;
 545
 546                         p += label_len + 1;
 547
 548                         if (*end == NULL)
 549                                 *end = p;
 550
 551                         if (p >= max)
 552                                 return -ENOBUFS;
 553                 }
 554         }
 555
 556         return 0;
 557 }
 558
 559 static int parse_rr(unsigned char *buf, unsigned char *start,
 560                         unsigned char *max,
 561                         unsigned char *response, unsigned int *response_size,
 562                         uint16_t *type, uint16_t *class, int *ttl, int *rdlen,
 563                         unsigned char **end,
 564                         char *name)
 565 {
 566         struct domain_rr *rr;
 567         int err, offset;
 568         int name_len = 0, output_len = 0, max_rsp = *response_size;
 569
 570         err = get_name(0, buf, start, max, response, max_rsp,
 571                 &output_len, end, name, &name_len);
 572         if (err < 0)
 573                 return err;
 574
 575         offset = output_len;
 576
 577         if ((unsigned int) offset > *response_size)
 578                 return -ENOBUFS;
 579
 580         rr = (void *) (*end);
 581
 582         *type = ntohs(rr->type);
 583         *class = ntohs(rr->class);
 584         *ttl = ntohl(rr->ttl);
 585         *rdlen = ntohs(rr->rdlen);
 586
 587         if (*ttl < 0)
 588                 return -EINVAL;
 589
 590         memcpy(response + offset, *end, sizeof(struct domain_rr));
 591
 592         offset += sizeof(struct domain_rr);
 593         *end += sizeof(struct domain_rr);
 594
 595         if ((unsigned int) (offset + *rdlen) > *response_size)
 596                 return -ENOBUFS;
 597
 598         memcpy(response + offset, *end, *rdlen);
 599
 600         *end += *rdlen;
 601
 602         *response_size = offset + *rdlen;
 603
 604         return 0;
 605 }
 606
 607 static gboolean check_alias(GSList *aliases, char *name)
 608 {
 609         GSList *list;
 610
 611         if (aliases != NULL) {
 612                 for (list = aliases; list; list = list->next) {
 613                         int len = strlen((char *)list->data);
 614                         if (strncmp((char *)list->data, name, len) == 0)
 615                                 return TRUE;
 616                 }
 617         }
 618
 619         return FALSE;
 620 }
 621
 622 static int parse_response(unsigned char *buf, int buflen,
 623                         char *question, int qlen,
 624                         uint16_t *type, uint16_t *class, int *ttl,
 625                         unsigned char *response, unsigned int *response_len,
 626                         uint16_t *answers)
 627 {
 628         struct domain_hdr *hdr = (void *) buf;
 629         struct domain_question *q;
 630         unsigned char *ptr;
 631         uint16_t qdcount = ntohs(hdr->qdcount);
 632         uint16_t ancount = ntohs(hdr->ancount);
 633         int err, i;
 634         uint16_t qtype, qclass;
 635         unsigned char *next = NULL;
 636         unsigned int maxlen = *response_len;
 637         GSList *aliases = NULL, *list;
 638         char name[NS_MAXDNAME + 1];
 639
 640         if (buflen < 12)
 641                 return -EINVAL;
 642
 643         DBG("qr %d qdcount %d", hdr->qr, qdcount);
 644
 645         /* We currently only cache responses where question count is 1 */
 646         if (hdr->qr != 1 || qdcount != 1)
 647                 return -EINVAL;
 648
 649         ptr = buf + sizeof(struct domain_hdr);
 650
 651         strncpy(question, (char *) ptr, qlen);
 652         qlen = strlen(question);
 653         ptr += qlen + 1; /* skip \0 */
 654
 655         q = (void *) ptr;
 656         qtype = ntohs(q->type);
 657
 658         /* We cache only A and AAAA records */
 659         if (qtype != 1 && qtype != 28)
 660                 return -ENOMSG;
 661
 662         qclass = ntohs(q->class);
 663
 664         ptr += 2 + 2; /* ptr points now to answers */
 665
 666         err = -ENOMSG;
 667         *response_len = 0;
 668         *answers = 0;
 669
 670         /*
 671          * We have a bunch of answers (like A, AAAA, CNAME etc) to
 672          * A or AAAA question. We traverse the answers and parse the
 673          * resource records. Only A and AAAA records are cached, all
 674          * the other records in answers are skipped.
 675          */
 676         for (i = 0; i < ancount; i++) {
 677                 /*
 678                  * Get one address at a time to this buffer.
 679                  * The max size of the answer is
 680                  *   2 (pointer) + 2 (type) + 2 (class) +
 681                  *   4 (ttl) + 2 (rdlen) + addr (16 or 4) = 28
 682                  * for A or AAAA record.
 683                  * For CNAME the size can be bigger.
 684                  */
 685                 unsigned char rsp[NS_MAXCDNAME];
 686                 unsigned int rsp_len = sizeof(rsp) - 1;
 687                 int ret, rdlen;
 688
 689                 memset(rsp, 0, sizeof(rsp));
 690
 691                 ret = parse_rr(buf, ptr, buf + buflen, rsp, &rsp_len,
 692                         type, class, ttl, &rdlen, &next, name);
 693                 if (ret != 0) {
 694                         err = ret;
 695                         goto out;
 696                 }
 697
 698                 /*
 699                  * Now rsp contains compressed or uncompressed resource
 700                  * record. Next we check if this record answers the question.
 701                  * The name var contains the uncompressed label.
 702                  * One tricky bit is the CNAME records as they alias
 703                  * the name we might be interested in.
 704                  */
 705
 706                 /*
 707                  * Go to next answer if the class is not the one we are
 708                  * looking for.
 709                  */
 710                 if (*class != qclass) {
 711                         ptr = next;
 712                         next = NULL;
 713                         continue;
 714                 }
 715
 716                 /*
 717                  * Try to resolve aliases also, type is CNAME(5).
 718                  * This is important as otherwise the aliased names would not
 719                  * be cached at all as the cache would not contain the aliased
 720                  * question.
 721                  *
 722                  * If any CNAME is found in DNS packet, then we cache the alias
 723                  * IP address instead of the question (as the server
 724                  * said that question has only an alias).
 725                  * This means in practice that if e.g., ipv6.google.com is
 726                  * queried, DNS server returns CNAME of that name which is
 727                  * ipv6.l.google.com. We then cache the address of the CNAME
 728                  * but return the question name to client. So the alias
 729                  * status of the name is not saved in cache and thus not
 730                  * returned to the client. We do not return DNS packets from
 731                  * cache to client saying that ipv6.google.com is an alias to
 732                  * ipv6.l.google.com but we return instead a DNS packet that
 733                  * says ipv6.google.com has address xxx which is in fact the
 734                  * address of ipv6.l.google.com. For caching purposes this
 735                  * should not cause any issues.
 736                  */
 737                 if (*type == 5 && strncmp(question, name, qlen) == 0) {
 738                         /*
 739                          * So now the alias answered the question. This is
 740                          * not very useful from caching point of view as
 741                          * the following A or AAAA records will not match the
 742                          * question. We need to find the real A/AAAA record
 743                          * of the alias and cache that.
 744                          */
 745                         unsigned char *end = NULL;
 746                         int name_len = 0, output_len;
 747
 748                         memset(rsp, 0, sizeof(rsp));
 749                         rsp_len = sizeof(rsp) - 1;
 750
 751                         /*
 752                          * Alias is in rdata part of the message,
 753                          * and next-rdlen points to it. So we need to get
 754                          * the real name of the alias.
 755                          */
 756                         ret = get_name(0, buf, next - rdlen, buf + buflen,
 757                                         rsp, rsp_len, &output_len, &end,
 758                                         name, &name_len);
 759                         if (ret != 0) {
 760                                 /* just ignore the error at this point */
 761                                 ptr = next;
 762                                 next = NULL;
 763                                 continue;
 764                         }
 765
 766                         /*
 767                          * We should now have the alias of the entry we might
 768                          * want to cache. Just remember it for a while.
 769                          * We check the alias list when we have parsed the
 770                          * A or AAAA record.
 771                          */
 772                         aliases = g_slist_prepend(aliases, g_strdup(name));
 773
 774                         ptr = next;
 775                         next = NULL;
 776                         continue;
 777                 }
 778
 779                 if (*type == qtype) {
 780                         /*
 781                          * We found correct type (A or AAAA)
 782                          */
 783                         if (check_alias(aliases, name) == TRUE ||
 784                                 (aliases == NULL && strncmp(question, name,
 785                                                         qlen) == 0)) {
 786                                 /*
 787                                  * We found an alias or the name of the rr
 788                                  * matches the question. If so, we append
 789                                  * the compressed label to the cache.
 790                                  * The end result is a response buffer that
 791                                  * will contain one or more cached and
 792                                  * compressed resource records.
 793                                  */
 794                                 if (*response_len + rsp_len > maxlen) {
 795                                         err = -ENOBUFS;
 796                                         goto out;
 797                                 }
 798                                 memcpy(response + *response_len, rsp, rsp_len);
 799                                 *response_len += rsp_len;
 800                                 (*answers)++;
 801                                 err = 0;
 802                         }
 803                 }
 804
 805                 ptr = next;
 806                 next = NULL;
 807         }
 808
 809 out:
 810         for (list = aliases; list; list = list->next)
 811                 g_free(list->data);
 812         g_slist_free(aliases);
 813
 814         return err;
 815 }
 816
 817 struct cache_timeout {
 818         time_t current_time;
 819         int max_timeout;
 820 };
 821
 822 static gboolean cache_check_entry(gpointer key, gpointer value,
 823                                         gpointer user_data)
 824 {
 825         struct cache_timeout *data = user_data;
 826         struct cache_entry *entry = value;
 827         int max_timeout;
 828
 829         /*
 830          * If either IPv4 or IPv6 cached entry has expired, we
 831          * remove both from the cache.
 832          */
 833
 834         if (entry->ipv4 != NULL && entry->ipv4->timeout > 0) {
 835                 max_timeout = entry->ipv4->inserted + entry->ipv4->timeout;
 836                 if (max_timeout > data->max_timeout)
 837                         data->max_timeout = max_timeout;
 838
 839                 if (entry->ipv4->inserted + entry->ipv4->timeout
 840                                                         < data->current_time)
 841                         return TRUE;
 842         }
 843
 844         if (entry->ipv6 != NULL && entry->ipv6->timeout > 0) {
 845                 max_timeout = entry->ipv6->inserted + entry->ipv6->timeout;
 846                 if (max_timeout > data->max_timeout)
 847                         data->max_timeout = max_timeout;
 848
 849                 if (entry->ipv6->inserted + entry->ipv6->timeout
 850                                                         < data->current_time)
 851                         return TRUE;
 852         }
 853
 854         return FALSE;
 855 }
 856
 857 static void cache_cleanup(void)
 858 {
 859         static int max_timeout;
 860         struct cache_timeout data;
 861         int count;
 862
 863         data.current_time = time(0);
 864         data.max_timeout = 0;
 865
 866         if (max_timeout > data.current_time) {
 867                 DBG("waiting %ld secs before cleaning cache",
 868                         max_timeout - data.current_time);
 869                 return;
 870         }
 871
 872         count = g_hash_table_foreach_remove(cache, cache_check_entry,
 873                                                 &data);
 874         DBG("removed %d", count);
 875
 876         if (count == 0)
 877                 /*
 878                  * If we could not remove anything, then remember
 879                  * what is the max timeout and do nothing if we
 880                  * have not yet reached it. This will prevent
 881                  * constant traversal of the cache if it is full.
 882                  */
 883                 max_timeout = data.max_timeout;
 884         else
 885                 max_timeout = 0;
 886 }
 887
 888 static int cache_update(struct server_data *srv, unsigned char *msg,
 889                         unsigned int msg_len)
 890 {
 891         int offset = protocol_offset(srv->protocol);
 892         int err, qlen, ttl = 0;
 893         uint16_t answers, type = 0, class = 0;
 894         struct domain_question *q;
 895         struct cache_entry *entry;
 896         struct cache_data *data;
 897         char question[NS_MAXDNAME + 1];
 898         unsigned char response[NS_MAXDNAME + 1];
 899         unsigned char *ptr;
 900         unsigned int rsplen;
 901         gboolean new_entry = TRUE;
 902         time_t current_time;
 903
 904         if (cache_size >= MAX_CACHE_SIZE) {
 905                 cache_cleanup();
 906                 if (cache_size >= MAX_CACHE_SIZE)
 907                         return 0;
 908         }
 909
 910         /* Continue only if response code is 0 (=ok) */
 911         if (msg[3] & 0x0f)
 912                 return 0;
 913
 914         if (offset < 0)
 915                 return 0;
 916
 917         rsplen = sizeof(response) - 1;
 918         question[sizeof(question) - 1] = '\0';
 919
 920         err = parse_response(msg + offset, msg_len - offset,
 921                                 question, sizeof(question) - 1,
 922                                 &type, &class, &ttl,
 923                                 response, &rsplen, &answers);
 924         if (err < 0 || ttl == 0)
 925                 return 0;
 926
 927         qlen = strlen(question);
 928         current_time = time(0);
 929
 930         /*
 931          * If the cache contains already data, check if the
 932          * type of the cached data is the same and do not add
 933          * to cache if data is already there.
 934          * This is needed so that we can cache both A and AAAA
 935          * records for the same name.
 936          */
 937         entry = g_hash_table_lookup(cache, question);
 938         if (entry == NULL) {
 939                 entry = g_try_new(struct cache_entry, 1);
 940                 if (entry == NULL)
 941                         return -ENOMEM;
 942
 943                 data = g_try_new(struct cache_data, 1);
 944                 if (data == NULL) {
 945                         g_free(entry);
 946                         return -ENOMEM;
 947                 }
 948
 949                 entry->key = g_strdup(question);
 950                 entry->ipv4 = entry->ipv6 = NULL;
 951
 952                 if (type == 1)
 953                         entry->ipv4 = data;
 954                 else
 955                         entry->ipv6 = data;
 956         } else {
 957                 if (type == 1 && entry->ipv4 != NULL)
 958                         return 0;
 959
 960                 if (type == 28 && entry->ipv6 != NULL)
 961                         return 0;
 962
 963                 data = g_try_new(struct cache_data, 1);
 964                 if (data == NULL)
 965                         return -ENOMEM;
 966
 967                 if (type == 1)
 968                         entry->ipv4 = data;
 969                 else
 970                         entry->ipv6 = data;
 971
 972                 new_entry = FALSE;
 973         }
 974
 975         /*
 976          * Restrict the cached DNS record TTL to some sane value
 977          * in order to prevent data staying in the cache too long.
 978          */
 979         if (ttl > MAX_CACHE_TTL)
 980                 ttl = MAX_CACHE_TTL;
 981
 982         data->inserted = current_time;
 983         data->type = type;
 984         data->answers = answers;
 985         data->timeout = ttl;
 986         data->data_len = 12 + qlen + 1 + 2 + 2 + rsplen;
 987         data->data = ptr = g_malloc(data->data_len);
 988         if (data->data == NULL) {
 989                 g_free(entry->key);
 990                 g_free(data);
 991                 g_free(entry);
 992                 return -ENOMEM;
 993         }
 994
 995         memcpy(ptr, msg, 12);
 996         memcpy(ptr + 12, question, qlen + 1); /* copy also the \0 */
 997
 998         q = (void *) (ptr + 12 + qlen + 1);
 999         q->type = htons(type);
1000         q->class = htons(class);
1001         memcpy(ptr + 12 + qlen + 1 + sizeof(struct domain_question),
1002                 response, rsplen);
1003
1004         if (new_entry == TRUE) {
1005                 g_hash_table_replace(cache, entry->key, entry);
1006                 cache_size++;
1007         }
1008
1009         DBG("cache %d %squestion \"%s\" type %d ttl %d size %zd",
1010                 cache_size, new_entry ? "new " : "old ",
1011                 question, type, ttl,
1012                 sizeof(*entry) + sizeof(*data) + data->data_len + qlen);
1013
1014         return 0;
1015 }
1016
1017 static int ns_resolv(struct server_data *server, struct request_data *req,
1018                                 gpointer request, gpointer name)
1019 {
1020         GList *list;
1021         int sk, err, type = 0;
1022         char *dot, *lookup = (char *) name;
1023         struct cache_entry *entry;
1024
1025         entry = cache_check(request, &type);
1026         if (entry != NULL) {
1027                 struct cache_data *data;
1028
1029                 DBG("cache hit %s type %s", lookup, type == 1 ? "A" : "AAAA");
1030                 if (type == 1)
1031                         data = entry->ipv4;
1032                 else
1033                         data = entry->ipv6;
1034
1035                 if (data != NULL && req->protocol == IPPROTO_TCP) {
1036                         send_cached_response(req->client_sk, data->data,
1037                                         data->data_len, NULL, 0, IPPROTO_TCP,
1038                                         req->srcid, data->answers);
1039                         return 1;
1040                 }
1041
1042                 if (data != NULL && req->protocol == IPPROTO_UDP) {
1043                         int sk;
1044                         sk = g_io_channel_unix_get_fd(
1045                                         req->ifdata->udp_listener_channel);
1046
1047                         send_cached_response(sk, data->data,
1048                                 data->data_len, &req->sa, req->sa_len,
1049                                 IPPROTO_UDP, req->srcid, data->answers);
1050                         return 1;
1051                 }
1052         }
1053
1054         sk = g_io_channel_unix_get_fd(server->channel);
1055
1056         err = send(sk, request, req->request_len, 0);
1057
1058         req->numserv++;
1059
1060         /* If we have more than one dot, we don't add domains */
1061         dot = strchr(lookup, '.');
1062         if (dot != NULL && dot != lookup + strlen(lookup) - 1)
1063                 return 0;
1064
1065         if (server->domains != NULL && server->domains->data != NULL)
1066                 req->append_domain = TRUE;
1067
1068         for (list = server->domains; list; list = list->next) {
1069                 char *domain;
1070                 unsigned char alt[1024];
1071                 struct domain_hdr *hdr = (void *) &alt;
1072                 int altlen, domlen, offset;
1073
1074                 domain = list->data;
1075
1076                 if (domain == NULL)
1077                         continue;
1078
1079                 offset = protocol_offset(server->protocol);
1080                 if (offset < 0)
1081                         return offset;
1082
1083                 domlen = strlen(domain) + 1;
1084                 if (domlen < 5)
1085                         return -EINVAL;
1086
1087                 alt[offset] = req->altid & 0xff;
1088                 alt[offset + 1] = req->altid >> 8;
1089
1090                 memcpy(alt + offset + 2, request + offset + 2, 10);
1091                 hdr->qdcount = htons(1);
1092
1093                 altlen = append_query(alt + offset + 12, sizeof(alt) - 12,
1094                                         name, domain);
1095                 if (altlen < 0)
1096                         return -EINVAL;
1097
1098                 altlen += 12;
1099
1100                 memcpy(alt + offset + altlen,
1101                         request + offset + altlen - domlen,
1102                                 req->request_len - altlen - offset + domlen);
1103
1104                 if (server->protocol == IPPROTO_TCP) {
1105                         int req_len = req->request_len + domlen - 2;
1106
1107                         alt[0] = (req_len >> 8) & 0xff;
1108                         alt[1] = req_len & 0xff;
1109                 }
1110
1111                 err = send(sk, alt, req->request_len + domlen, 0);
1112                 if (err < 0)
1113                         return -EIO;
1114
1115                 req->numserv++;
1116         }
1117
1118         return 0;
1119 }
1120
1121 static int forward_dns_reply(unsigned char *reply, int reply_len, int protocol,
1122                                 struct server_data *data)
1123 {
1124         struct domain_hdr *hdr;
1125         struct request_data *req;
1126         int dns_id, sk, err, offset = protocol_offset(protocol);
1127         struct listener_data *ifdata;
1128
1129         if (offset < 0)
1130                 return offset;
1131
1132         hdr = (void *)(reply + offset);
1133         dns_id = reply[offset] | reply[offset + 1] << 8;
1134
1135         DBG("Received %d bytes (id 0x%04x)", reply_len, dns_id);
1136
1137         req = find_request(dns_id);
1138         if (req == NULL)
1139                 return -EINVAL;
1140
1141         DBG("id 0x%04x rcode %d", hdr->id, hdr->rcode);
1142
1143         ifdata = req->ifdata;
1144
1145         reply[offset] = req->srcid & 0xff;
1146         reply[offset + 1] = req->srcid >> 8;
1147
1148         req->numresp++;
1149
1150         if (hdr->rcode == 0 || req->resp == NULL) {
1151
1152                 /*
1153                  * If the domain name was append
1154                  * remove it before forwarding the reply.
1155                  */
1156                 if (req->append_domain == TRUE) {
1157                         unsigned char *ptr;
1158                         uint8_t host_len;
1159                         unsigned int domain_len;
1160
1161                         /*
1162                          * ptr points to the first char of the hostname.
1163                          * ->hostname.domain.net
1164                          */
1165                         ptr = reply + offset + sizeof(struct domain_hdr);
1166                         host_len = *ptr;
1167                         domain_len = strlen((const char *)ptr) - host_len - 1;
1168
1169                         /*
1170                          * remove the domain name and replaced it by the end
1171                          * of reply.
1172                          */
1173                         memmove(ptr + host_len + 1,
1174                                 ptr + host_len + domain_len + 1,
1175                                 reply_len - (ptr - reply + domain_len));
1176
1177                         reply_len = reply_len - domain_len;
1178                 }
1179
1180                 g_free(req->resp);
1181                 req->resplen = 0;
1182
1183                 req->resp = g_try_malloc(reply_len);
1184                 if (req->resp == NULL)
1185                         return -ENOMEM;
1186
1187                 memcpy(req->resp, reply, reply_len);
1188                 req->resplen = reply_len;
1189
1190                 cache_update(data, reply, reply_len);
1191         }
1192
1193         if (hdr->rcode > 0 && req->numresp < req->numserv)
1194                 return -EINVAL;
1195
1196         if (req->timeout > 0)
1197                 g_source_remove(req->timeout);
1198
1199         request_list = g_slist_remove(request_list, req);
1200
1201         if (protocol == IPPROTO_UDP) {
1202                 sk = g_io_channel_unix_get_fd(ifdata->udp_listener_channel);
1203                 err = sendto(sk, req->resp, req->resplen, 0,
1204                              &req->sa, req->sa_len);
1205         } else {
1206                 sk = req->client_sk;
1207                 err = send(sk, req->resp, req->resplen, 0);
1208                 close(sk);
1209         }
1210
1211         g_free(req->resp);
1212         g_free(req);
1213
1214         return err;
1215 }
1216
1217 static void cache_element_destroy(gpointer value)
1218 {
1219         struct cache_entry *entry = value;
1220
1221         if (entry == NULL)
1222                 return;
1223
1224         if (entry->ipv4 != NULL) {
1225                 g_free(entry->ipv4->data);
1226                 g_free(entry->ipv4);
1227         }
1228
1229         if (entry->ipv6 != NULL) {
1230                 g_free(entry->ipv6->data);
1231                 g_free(entry->ipv6);
1232         }
1233
1234         g_free(entry->key);
1235         g_free(entry);
1236
1237         if (--cache_size < 0)
1238                 cache_size = 0;
1239 }
1240
1241 static void destroy_server(struct server_data *server)
1242 {
1243         GList *list;
1244
1245         DBG("interface %s server %s", server->interface, server->server);
1246
1247         server_list = g_slist_remove(server_list, server);
1248
1249         if (server->watch > 0)
1250                 g_source_remove(server->watch);
1251
1252         if (server->timeout > 0)
1253                 g_source_remove(server->timeout);
1254
1255         g_io_channel_unref(server->channel);
1256
1257         if (server->protocol == IPPROTO_UDP)
1258                 connman_info("Removing DNS server %s", server->server);
1259
1260         g_free(server->incoming_reply);
1261         g_free(server->server);
1262         for (list = server->domains; list; list = list->next) {
1263                 char *domain = list->data;
1264
1265                 server->domains = g_list_remove(server->domains, domain);
1266                 g_free(domain);
1267         }
1268         g_free(server->interface);
1269
1270         if (__sync_fetch_and_sub(&cache_refcount, 1) == 1)
1271                 g_hash_table_destroy(cache);
1272
1273         g_free(server);
1274 }
1275
1276 static gboolean udp_server_event(GIOChannel *channel, GIOCondition condition,
1277                                                         gpointer user_data)
1278 {
1279         unsigned char buf[4096];
1280         int sk, err, len;
1281         struct server_data *data = user_data;
1282
1283         if (condition & (G_IO_NVAL | G_IO_ERR | G_IO_HUP)) {
1284                 connman_error("Error with UDP server %s", data->server);
1285                 data->watch = 0;
1286                 return FALSE;
1287         }
1288
1289         sk = g_io_channel_unix_get_fd(channel);
1290
1291         len = recv(sk, buf, sizeof(buf), 0);
1292         if (len < 12)
1293                 return TRUE;
1294
1295         err = forward_dns_reply(buf, len, IPPROTO_UDP, data);
1296         if (err < 0)
1297                 return TRUE;
1298
1299         return TRUE;
1300 }
1301
1302 static gboolean tcp_server_event(GIOChannel *channel, GIOCondition condition,
1303                                                         gpointer user_data)
1304 {
1305         int sk;
1306         struct server_data *server = user_data;
1307
1308         sk = g_io_channel_unix_get_fd(channel);
1309         if (sk == 0)
1310                 return FALSE;
1311
1312         if (condition & (G_IO_NVAL | G_IO_ERR | G_IO_HUP)) {
1313                 GSList *list;
1314 hangup:
1315                 DBG("TCP server channel closed");
1316
1317                 /*
1318                  * Discard any partial response which is buffered; better
1319                  * to get a proper response from a working server.
1320                  */
1321                 g_free(server->incoming_reply);
1322                 server->incoming_reply = NULL;
1323
1324                 for (list = request_list; list; list = list->next) {
1325                         struct request_data *req = list->data;
1326                         struct domain_hdr *hdr;
1327
1328                         if (req->protocol == IPPROTO_UDP)
1329                                 continue;
1330
1331                         if (req->request == NULL)
1332                                 continue;
1333
1334                         /*
1335                          * If we're not waiting for any further response
1336                          * from another name server, then we send an error
1337                          * response to the client.
1338                          */
1339                         if (req->numserv && --(req->numserv))
1340                                 continue;
1341
1342                         hdr = (void *) (req->request + 2);
1343                         hdr->id = req->srcid;
1344                         send_response(req->client_sk, req->request,
1345                                 req->request_len, NULL, 0, IPPROTO_TCP);
1346
1347                         request_list = g_slist_remove(request_list, req);
1348                 }
1349
1350                 destroy_server(server);
1351
1352                 return FALSE;
1353         }
1354
1355         if ((condition & G_IO_OUT) && !server->connected) {
1356                 GSList *list;
1357                 GList *domains;
1358                 struct server_data *udp_server;
1359
1360                 udp_server = find_server(server->interface, server->server,
1361                                                                 IPPROTO_UDP);
1362                 if (udp_server != NULL) {
1363                         for (domains = udp_server->domains; domains;
1364                                                 domains = domains->next) {
1365                                 char *dom = domains->data;
1366
1367                                 DBG("Adding domain %s to %s",
1368                                                 dom, server->server);
1369
1370                                 server->domains = g_list_append(server->domains,
1371                                                                 g_strdup(dom));
1372                         }
1373                 }
1374
1375                 server->connected = TRUE;
1376                 server_list = g_slist_append(server_list, server);
1377
1378                 if (server->timeout > 0) {
1379                         g_source_remove(server->timeout);
1380                         server->timeout = 0;
1381                 }
1382
1383                 for (list = request_list; list; list = list->next) {
1384                         struct request_data *req = list->data;
1385
1386                         if (req->protocol == IPPROTO_UDP)
1387                                 continue;
1388
1389                         DBG("Sending req %s over TCP", (char *)req->name);
1390
1391                         if (req->timeout > 0)
1392                                 g_source_remove(req->timeout);
1393
1394                         req->timeout = g_timeout_add_seconds(30,
1395                                                 request_timeout, req);
1396                         if (ns_resolv(server, req, req->request,
1397                                         req->name) > 0) {
1398                                 /* We sent cached result so no need for timeout
1399                                  * handler.
1400                                  */
1401                                 if (req->timeout > 0) {
1402                                         g_source_remove(req->timeout);
1403                                         req->timeout = 0;
1404                                 }
1405                         }
1406                 }
1407
1408         } else if (condition & G_IO_IN) {
1409                 struct partial_reply *reply = server->incoming_reply;
1410                 int bytes_recv;
1411
1412                 if (!reply) {
1413                         unsigned char reply_len_buf[2];
1414                         uint16_t reply_len;
1415
1416                         bytes_recv = recv(sk, reply_len_buf, 2, MSG_PEEK);
1417                         if (!bytes_recv) {
1418                                 goto hangup;
1419                         } else if (bytes_recv < 0) {
1420                                 if (errno == EAGAIN || errno == EWOULDBLOCK)
1421                                         return TRUE;
1422
1423                                 connman_error("DNS proxy error %s",
1424                                                 strerror(errno));
1425                                 goto hangup;
1426                         } else if (bytes_recv < 2)
1427                                 return TRUE;
1428
1429                         reply_len = reply_len_buf[1] | reply_len_buf[0] << 8;
1430                         reply_len += 2;
1431
1432                         DBG("TCP reply %d bytes", reply_len);
1433
1434                         reply = g_try_malloc(sizeof(*reply) + reply_len + 2);
1435                         if (!reply)
1436                                 return TRUE;
1437
1438                         reply->len = reply_len;
1439                         reply->received = 0;
1440
1441                         server->incoming_reply = reply;
1442                 }
1443
1444                 while (reply->received < reply->len) {
1445                         bytes_recv = recv(sk, reply->buf + reply->received,
1446                                         reply->len - reply->received, 0);
1447                         if (!bytes_recv) {
1448                                 connman_error("DNS proxy TCP disconnect");
1449                                 break;
1450                         } else if (bytes_recv < 0) {
1451                                 if (errno == EAGAIN || errno == EWOULDBLOCK)
1452                                         return TRUE;
1453
1454                                 connman_error("DNS proxy error %s",
1455                                                 strerror(errno));
1456                                 break;
1457                         }
1458                         reply->received += bytes_recv;
1459                 }
1460
1461                 forward_dns_reply(reply->buf, reply->received, IPPROTO_TCP,
1462                                         server);
1463
1464                 g_free(reply);
1465                 server->incoming_reply = NULL;
1466
1467                 destroy_server(server);
1468
1469                 return FALSE;
1470         }
1471
1472         return TRUE;
1473 }
1474
1475 static gboolean tcp_idle_timeout(gpointer user_data)
1476 {
1477         struct server_data *server = user_data;
1478
1479         DBG("");
1480
1481         if (server == NULL)
1482                 return FALSE;
1483
1484         destroy_server(server);
1485
1486         return FALSE;
1487 }
1488
1489 static struct server_data *create_server(const char *interface,
1490                                         const char *domain, const char *server,
1491                                         int protocol)
1492 {
1493         struct addrinfo hints, *rp;
1494         struct server_data *data;
1495         int sk, ret;
1496
1497         DBG("interface %s server %s", interface, server);
1498
1499         memset(&hints, 0, sizeof(hints));
1500
1501         switch (protocol) {
1502         case IPPROTO_UDP:
1503                 hints.ai_socktype = SOCK_DGRAM;
1504                 break;
1505
1506         case IPPROTO_TCP:
1507                 hints.ai_socktype = SOCK_STREAM;
1508                 break;
1509
1510         default:
1511                 return NULL;
1512         }
1513         hints.ai_family = AF_UNSPEC;
1514         hints.ai_flags = AI_PASSIVE | AI_NUMERICSERV | AI_NUMERICHOST;
1515
1516         ret = getaddrinfo(server, "53", &hints, &rp);
1517         if (ret) {
1518                 connman_error("Failed to parse server %s address: %s\n",
1519                               server, gai_strerror(ret));
1520                 return NULL;
1521         }
1522         /* Do not blindly copy this code elsewhere; it doesn't loop over the
1523            results using ->ai_next as it should. That's OK in *this* case
1524            because it was a numeric lookup; we *know* there's only one. */
1525
1526         sk = socket(rp->ai_family, rp->ai_socktype, rp->ai_protocol);
1527         if (sk < 0) {
1528                 connman_error("Failed to create server %s socket", server);
1529                 freeaddrinfo(rp);
1530                 return NULL;
1531         }
1532
1533         if (interface != NULL) {
1534                 if (setsockopt(sk, SOL_SOCKET, SO_BINDTODEVICE,
1535                                 interface, strlen(interface) + 1) < 0) {
1536                         connman_error("Failed to bind server %s "
1537                                                 "to interface %s",
1538                                                         server, interface);
1539                         freeaddrinfo(rp);
1540                         close(sk);
1541                         return NULL;
1542                 }
1543         }
1544
1545         data = g_try_new0(struct server_data, 1);
1546         if (data == NULL) {
1547                 connman_error("Failed to allocate server %s data", server);
1548                 freeaddrinfo(rp);
1549                 close(sk);
1550                 return NULL;
1551         }
1552
1553         data->channel = g_io_channel_unix_new(sk);
1554         if (data->channel == NULL) {
1555                 connman_error("Failed to create server %s channel", server);
1556                 freeaddrinfo(rp);
1557                 close(sk);
1558                 g_free(data);
1559                 return NULL;
1560         }
1561
1562         g_io_channel_set_close_on_unref(data->channel, TRUE);
1563
1564         if (protocol == IPPROTO_TCP) {
1565                 g_io_channel_set_flags(data->channel, G_IO_FLAG_NONBLOCK, NULL);
1566                 data->watch = g_io_add_watch(data->channel,
1567                         G_IO_OUT | G_IO_IN | G_IO_HUP | G_IO_NVAL | G_IO_ERR,
1568                                                 tcp_server_event, data);
1569                 data->timeout = g_timeout_add_seconds(30, tcp_idle_timeout,
1570                                                                 data);
1571         } else
1572                 data->watch = g_io_add_watch(data->channel,
1573                         G_IO_IN | G_IO_NVAL | G_IO_ERR | G_IO_HUP,
1574                                                 udp_server_event, data);
1575
1576         data->interface = g_strdup(interface);
1577         if (domain)
1578                 data->domains = g_list_append(data->domains, g_strdup(domain));
1579         data->server = g_strdup(server);
1580         data->protocol = protocol;
1581
1582         ret = connect(sk, rp->ai_addr, rp->ai_addrlen);
1583         freeaddrinfo(rp);
1584         if (ret < 0) {
1585                 if ((protocol == IPPROTO_TCP && errno != EINPROGRESS) ||
1586                                 protocol == IPPROTO_UDP) {
1587                         GList *list;
1588
1589                         connman_error("Failed to connect to server %s", server);
1590                         if (data->watch > 0)
1591                                 g_source_remove(data->watch);
1592                         if (data->timeout > 0)
1593                                 g_source_remove(data->timeout);
1594
1595                         g_io_channel_unref(data->channel);
1596                         close(sk);
1597
1598                         g_free(data->server);
1599                         g_free(data->interface);
1600                         for (list = data->domains; list; list = list->next) {
1601                                 char *domain = list->data;
1602
1603                                 data->domains = g_list_remove(data->domains,
1604                                                                         domain);
1605                                 g_free(domain);
1606                         }
1607                         g_free(data);
1608                         return NULL;
1609                 }
1610         }
1611
1612         if (__sync_fetch_and_add(&cache_refcount, 1) == 0)
1613                 cache = g_hash_table_new_full(g_str_hash,
1614                                         g_str_equal,
1615                                         NULL,
1616                                         cache_element_destroy);
1617
1618         if (protocol == IPPROTO_UDP) {
1619                 /* Enable new servers by default */
1620                 data->enabled = TRUE;
1621                 connman_info("Adding DNS server %s", data->server);
1622
1623                 server_list = g_slist_append(server_list, data);
1624
1625                 return data;
1626         }
1627
1628         return NULL;
1629 }
1630
1631 static gboolean resolv(struct request_data *req,
1632                                 gpointer request, gpointer name)
1633 {
1634         GSList *list;
1635         int status;
1636
1637         for (list = server_list; list; list = list->next) {
1638                 struct server_data *data = list->data;
1639
1640                 DBG("server %s enabled %d", data->server, data->enabled);
1641
1642                 if (data->enabled == FALSE)
1643                         continue;
1644
1645                 if (data->watch == 0 && data->protocol == IPPROTO_UDP)
1646                         data->watch = g_io_add_watch(data->channel,
1647                                 G_IO_IN | G_IO_NVAL | G_IO_ERR | G_IO_HUP,
1648                                                 udp_server_event, data);
1649
1650                 status = ns_resolv(data, req, request, name);
1651                 if (status < 0)
1652                         continue;
1653
1654                 if (status > 0) {
1655                         if (req->timeout > 0) {
1656                                 g_source_remove(req->timeout);
1657                                 req->timeout = 0;
1658                         }
1659                 }
1660         }
1661
1662         return TRUE;
1663 }
1664
1665 static void append_domain(const char *interface, const char *domain)
1666 {
1667         GSList *list;
1668
1669         DBG("interface %s domain %s", interface, domain);
1670
1671         if (domain == NULL)
1672                 return;
1673
1674         for (list = server_list; list; list = list->next) {
1675                 struct server_data *data = list->data;
1676                 GList *dom_list;
1677                 char *dom;
1678                 gboolean dom_found = FALSE;
1679
1680                 if (data->interface == NULL)
1681                         continue;
1682
1683                 if (g_str_equal(data->interface, interface) == FALSE)
1684                         continue;
1685
1686                 for (dom_list = data->domains; dom_list;
1687                                 dom_list = dom_list->next) {
1688                         dom = dom_list->data;
1689
1690                         if (g_str_equal(dom, domain)) {
1691                                 dom_found = TRUE;
1692                                 break;
1693                         }
1694                 }
1695
1696                 if (dom_found == FALSE) {
1697                         data->domains =
1698                                 g_list_append(data->domains, g_strdup(domain));
1699                 }
1700         }
1701 }
1702
1703 int __connman_dnsproxy_append(const char *interface, const char *domain,
1704                                                         const char *server)
1705 {
1706         struct server_data *data;
1707
1708         DBG("interface %s server %s", interface, server);
1709
1710         if (server == NULL && domain == NULL)
1711                 return -EINVAL;
1712
1713         if (server == NULL) {
1714                 append_domain(interface, domain);
1715
1716                 return 0;
1717         }
1718
1719         if (g_str_equal(server, "127.0.0.1") == TRUE)
1720                 return -ENODEV;
1721
1722         data = find_server(interface, server, IPPROTO_UDP);
1723         if (data != NULL) {
1724                 append_domain(interface, domain);
1725                 return 0;
1726         }
1727
1728         data = create_server(interface, domain, server, IPPROTO_UDP);
1729         if (data == NULL)
1730                 return -EIO;
1731
1732         return 0;
1733 }
1734
1735 static void remove_server(const char *interface, const char *domain,
1736                         const char *server, int protocol)
1737 {
1738         struct server_data *data;
1739
1740         data = find_server(interface, server, protocol);
1741         if (data == NULL)
1742                 return;
1743
1744         destroy_server(data);
1745 }
1746
1747 int __connman_dnsproxy_remove(const char *interface, const char *domain,
1748                                                         const char *server)
1749 {
1750         DBG("interface %s server %s", interface, server);
1751
1752         if (server == NULL)
1753                 return -EINVAL;
1754
1755         if (g_str_equal(server, "127.0.0.1") == TRUE)
1756                 return -ENODEV;
1757
1758         remove_server(interface, domain, server, IPPROTO_UDP);
1759         remove_server(interface, domain, server, IPPROTO_TCP);
1760
1761         return 0;
1762 }
1763
1764 void __connman_dnsproxy_flush(void)
1765 {
1766         GSList *list;
1767
1768         list = request_pending_list;
1769         while (list) {
1770                 struct request_data *req = list->data;
1771
1772                 list = list->next;
1773
1774                 request_pending_list =
1775                                 g_slist_remove(request_pending_list, req);
1776                 resolv(req, req->request, req->name);
1777                 g_free(req->request);
1778                 g_free(req->name);
1779         }
1780 }
1781
1782 static void dnsproxy_offline_mode(connman_bool_t enabled)
1783 {
1784         GSList *list;
1785
1786         DBG("enabled %d", enabled);
1787
1788         for (list = server_list; list; list = list->next) {
1789                 struct server_data *data = list->data;
1790
1791                 if (enabled == FALSE) {
1792                         connman_info("Enabling DNS server %s", data->server);
1793                         data->enabled = TRUE;
1794                 } else {
1795                         connman_info("Disabling DNS server %s", data->server);
1796                         data->enabled = FALSE;
1797                 }
1798         }
1799 }
1800
1801 static void dnsproxy_default_changed(struct connman_service *service)
1802 {
1803         GSList *list;
1804         char *interface;
1805
1806         DBG("service %p", service);
1807
1808         if (service == NULL) {
1809                 /* When no services are active, then disable DNS proxying */
1810                 dnsproxy_offline_mode(TRUE);
1811                 return;
1812         }
1813
1814         interface = connman_service_get_interface(service);
1815         if (interface == NULL)
1816                 return;
1817
1818         for (list = server_list; list; list = list->next) {
1819                 struct server_data *data = list->data;
1820
1821                 if (g_strcmp0(data->interface, interface) == 0) {
1822                         connman_info("Enabling DNS server %s", data->server);
1823                         data->enabled = TRUE;
1824                 } else {
1825                         connman_info("Disabling DNS server %s", data->server);
1826                         data->enabled = FALSE;
1827                 }
1828         }
1829
1830         g_free(interface);
1831 }
1832
1833 static struct connman_notifier dnsproxy_notifier = {
1834         .name                   = "dnsproxy",
1835         .default_changed        = dnsproxy_default_changed,
1836         .offline_mode           = dnsproxy_offline_mode,
1837 };
1838
1839 static unsigned char opt_edns0_type[2] = { 0x00, 0x29 };
1840
1841 static int parse_request(unsigned char *buf, int len,
1842                                         char *name, unsigned int size)
1843 {
1844         struct domain_hdr *hdr = (void *) buf;
1845         uint16_t qdcount = ntohs(hdr->qdcount);
1846         uint16_t arcount = ntohs(hdr->arcount);
1847         unsigned char *ptr;
1848         char *last_label = NULL;
1849         unsigned int remain, used = 0;
1850
1851         if (len < 12)
1852                 return -EINVAL;
1853
1854         DBG("id 0x%04x qr %d opcode %d qdcount %d arcount %d",
1855                                         hdr->id, hdr->qr, hdr->opcode,
1856                                                         qdcount, arcount);
1857
1858         if (hdr->qr != 0 || qdcount != 1)
1859                 return -EINVAL;
1860
1861         memset(name, 0, size);
1862
1863         ptr = buf + sizeof(struct domain_hdr);
1864         remain = len - sizeof(struct domain_hdr);
1865
1866         while (remain > 0) {
1867                 uint8_t len = *ptr;
1868
1869                 if (len == 0x00) {
1870                         last_label = (char *) (ptr + 1);
1871                         break;
1872                 }
1873
1874                 if (used + len + 1 > size)
1875                         return -ENOBUFS;
1876
1877                 strncat(name, (char *) (ptr + 1), len);
1878                 strcat(name, ".");
1879
1880                 used += len + 1;
1881
1882                 ptr += len + 1;
1883                 remain -= len + 1;
1884         }
1885
1886         if (last_label && arcount && remain >= 9 && last_label[4] == 0 &&
1887                                 !memcmp(last_label + 5, opt_edns0_type, 2)) {
1888                 uint16_t edns0_bufsize;
1889
1890                 edns0_bufsize = last_label[7] << 8 | last_label[8];
1891
1892                 DBG("EDNS0 buffer size %u", edns0_bufsize);
1893
1894                 /* This is an evil hack until full TCP support has been
1895                  * implemented.
1896                  *
1897                  * Somtimes the EDNS0 request gets send with a too-small
1898                  * buffer size. Since glibc doesn't seem to crash when it
1899                  * gets a response biffer then it requested, just bump
1900                  * the buffer size up to 4KiB.
1901                  */
1902                 if (edns0_bufsize < 0x1000) {
1903                         last_label[7] = 0x10;
1904                         last_label[8] = 0x00;
1905                 }
1906         }
1907
1908         DBG("query %s", name);
1909
1910         return 0;
1911 }
1912
1913 static gboolean tcp_listener_event(GIOChannel *channel, GIOCondition condition,
1914                                                         gpointer user_data)
1915 {
1916         unsigned char buf[768];
1917         char query[512];
1918         struct request_data *req;
1919         struct server_data *server;
1920         int sk, client_sk, len, err;
1921         struct sockaddr_in6 client_addr;
1922         socklen_t client_addr_len = sizeof(client_addr);
1923         GSList *list;
1924         struct listener_data *ifdata = user_data;
1925
1926         DBG("condition 0x%x", condition);
1927
1928         if (condition & (G_IO_NVAL | G_IO_ERR | G_IO_HUP)) {
1929                 if (ifdata->tcp_listener_watch > 0)
1930                         g_source_remove(ifdata->tcp_listener_watch);
1931                 ifdata->tcp_listener_watch = 0;
1932
1933                 connman_error("Error with TCP listener channel");
1934
1935                 return FALSE;
1936         }
1937
1938         sk = g_io_channel_unix_get_fd(channel);
1939
1940         client_sk = accept(sk, (void *)&client_addr, &client_addr_len);
1941         if (client_sk < 0) {
1942                 connman_error("Accept failure on TCP listener");
1943                 ifdata->tcp_listener_watch = 0;
1944                 return FALSE;
1945         }
1946
1947         len = recv(client_sk, buf, sizeof(buf), 0);
1948         if (len < 2)
1949                 return TRUE;
1950
1951         DBG("Received %d bytes (id 0x%04x)", len, buf[2] | buf[3] << 8);
1952
1953         err = parse_request(buf + 2, len - 2, query, sizeof(query));
1954         if (err < 0 || (g_slist_length(server_list) == 0)) {
1955                 send_response(client_sk, buf, len, NULL, 0, IPPROTO_TCP);
1956                 return TRUE;
1957         }
1958
1959         req = g_try_new0(struct request_data, 1);
1960         if (req == NULL)
1961                 return TRUE;
1962
1963         memcpy(&req->sa, &client_addr, client_addr_len);
1964         req->sa_len = client_addr_len;
1965         req->client_sk = client_sk;
1966         req->protocol = IPPROTO_TCP;
1967
1968         request_id += 2;
1969         if (request_id == 0x0000 || request_id == 0xffff)
1970                 request_id += 2;
1971
1972         req->srcid = buf[2] | (buf[3] << 8);
1973         req->dstid = request_id;
1974         req->altid = request_id + 1;
1975         req->request_len = len;
1976
1977         buf[2] = req->dstid & 0xff;
1978         buf[3] = req->dstid >> 8;
1979
1980         req->numserv = 0;
1981         req->ifdata = (struct listener_data *) ifdata;
1982         req->append_domain = FALSE;
1983         request_list = g_slist_append(request_list, req);
1984
1985         for (list = server_list; list; list = list->next) {
1986                 struct server_data *data = list->data;
1987                 GList *domains;
1988
1989                 if (data->protocol != IPPROTO_UDP || data->enabled == FALSE)
1990                         continue;
1991
1992                 server = create_server(data->interface, NULL,
1993                                         data->server, IPPROTO_TCP);
1994
1995                 /*
1996                  * If server is NULL, we're not connected yet.
1997                  * Copy the relevant buffers and continue with
1998                  * the next nameserver.
1999                  * The request will actually be sent once we're
2000                  * properly connected over TCP to this nameserver.
2001                  */
2002                 if (server == NULL) {
2003                         req->request = g_try_malloc0(req->request_len);
2004                         if (req->request == NULL)
2005                                 return TRUE;
2006
2007                         memcpy(req->request, buf, req->request_len);
2008
2009                         req->name = g_try_malloc0(sizeof(query));
2010                         if (req->name == NULL) {
2011                                 g_free(req->request);
2012                                 return TRUE;
2013                         }
2014                         memcpy(req->name, query, sizeof(query));
2015
2016                         continue;
2017                 }
2018
2019                 if (req->timeout > 0)
2020                         g_source_remove(req->timeout);
2021
2022                 for (domains = data->domains; domains;
2023                                 domains = domains->next) {
2024                         char *dom = domains->data;
2025
2026                         DBG("Adding domain %s to %s", dom, server->server);
2027
2028                         server->domains = g_list_append(server->domains,
2029                                                 g_strdup(dom));
2030                 }
2031
2032                 req->timeout = g_timeout_add_seconds(30, request_timeout, req);
2033                 if (ns_resolv(server, req, buf, query) > 0) {
2034                         if (req->timeout > 0) {
2035                                 g_source_remove(req->timeout);
2036                                 req->timeout = 0;
2037                         }
2038                 }
2039         }
2040
2041         return TRUE;
2042 }
2043
2044 static gboolean udp_listener_event(GIOChannel *channel, GIOCondition condition,
2045                                                         gpointer user_data)
2046 {
2047         unsigned char buf[768];
2048         char query[512];
2049         struct request_data *req;
2050         struct sockaddr_in6 client_addr;
2051         socklen_t client_addr_len = sizeof(client_addr);
2052         int sk, err, len;
2053         struct listener_data *ifdata = user_data;
2054
2055         if (condition & (G_IO_NVAL | G_IO_ERR | G_IO_HUP)) {
2056                 connman_error("Error with UDP listener channel");
2057                 ifdata->udp_listener_watch = 0;
2058                 return FALSE;
2059         }
2060
2061         sk = g_io_channel_unix_get_fd(channel);
2062
2063         memset(&client_addr, 0, client_addr_len);
2064         len = recvfrom(sk, buf, sizeof(buf), 0, (void *)&client_addr,
2065                        &client_addr_len);
2066         if (len < 2)
2067                 return TRUE;
2068
2069         DBG("Received %d bytes (id 0x%04x)", len, buf[0] | buf[1] << 8);
2070
2071         err = parse_request(buf, len, query, sizeof(query));
2072         if (err < 0 || (g_slist_length(server_list) == 0)) {
2073                 send_response(sk, buf, len, (void *)&client_addr,
2074                                 client_addr_len, IPPROTO_UDP);
2075                 return TRUE;
2076         }
2077
2078         req = g_try_new0(struct request_data, 1);
2079         if (req == NULL)
2080                 return TRUE;
2081
2082         memcpy(&req->sa, &client_addr, client_addr_len);
2083         req->sa_len = client_addr_len;
2084         req->client_sk = 0;
2085         req->protocol = IPPROTO_UDP;
2086
2087         request_id += 2;
2088         if (request_id == 0x0000 || request_id == 0xffff)
2089                 request_id += 2;
2090
2091         req->srcid = buf[0] | (buf[1] << 8);
2092         req->dstid = request_id;
2093         req->altid = request_id + 1;
2094         req->request_len = len;
2095
2096         buf[0] = req->dstid & 0xff;
2097         buf[1] = req->dstid >> 8;
2098
2099         req->numserv = 0;
2100         req->ifdata = (struct listener_data *) ifdata;
2101         req->timeout = g_timeout_add_seconds(5, request_timeout, req);
2102         req->append_domain = FALSE;
2103         request_list = g_slist_append(request_list, req);
2104
2105         return resolv(req, buf, query);
2106 }
2107
2108 static int create_dns_listener(int protocol, struct listener_data *ifdata)
2109 {
2110         GIOChannel *channel;
2111         const char *proto;
2112         union {
2113                 struct sockaddr sa;
2114                 struct sockaddr_in6 sin6;
2115                 struct sockaddr_in sin;
2116         } s;
2117         socklen_t slen;
2118         int sk, type, v6only = 0;
2119         int family = AF_INET6;
2120
2121
2122         DBG("interface %s", ifdata->ifname);
2123
2124         switch (protocol) {
2125         case IPPROTO_UDP:
2126                 proto = "UDP";
2127                 type = SOCK_DGRAM | SOCK_CLOEXEC;
2128                 break;
2129
2130         case IPPROTO_TCP:
2131                 proto = "TCP";
2132                 type = SOCK_STREAM | SOCK_CLOEXEC;
2133                 break;
2134
2135         default:
2136                 return -EINVAL;
2137         }
2138
2139         sk = socket(family, type, protocol);
2140         if (sk < 0 && family == AF_INET6 && errno == EAFNOSUPPORT) {
2141                 connman_error("No IPv6 support; DNS proxy listening only on Legacy IP");
2142                 family = AF_INET;
2143                 sk = socket(family, type, protocol);
2144         }
2145         if (sk < 0) {
2146                 connman_error("Failed to create %s listener socket", proto);
2147                 return -EIO;
2148         }
2149
2150         if (setsockopt(sk, SOL_SOCKET, SO_BINDTODEVICE,
2151                                         ifdata->ifname,
2152                                         strlen(ifdata->ifname) + 1) < 0) {
2153                 connman_error("Failed to bind %s listener interface", proto);
2154                 close(sk);
2155                 return -EIO;
2156         }
2157         /* Ensure it accepts Legacy IP connections too */
2158         if (family == AF_INET6 &&
2159                         setsockopt(sk, SOL_IPV6, IPV6_V6ONLY,
2160                                         &v6only, sizeof(v6only)) < 0) {
2161                 connman_error("Failed to clear V6ONLY on %s listener socket",
2162                               proto);
2163                 close(sk);
2164                 return -EIO;
2165         }
2166
2167         if (family == AF_INET) {
2168                 memset(&s.sin, 0, sizeof(s.sin));
2169                 s.sin.sin_family = AF_INET;
2170                 s.sin.sin_port = htons(53);
2171                 s.sin.sin_addr.s_addr = htonl(INADDR_ANY);
2172                 slen = sizeof(s.sin);
2173         } else {
2174                 memset(&s.sin6, 0, sizeof(s.sin6));
2175                 s.sin6.sin6_family = AF_INET6;
2176                 s.sin6.sin6_port = htons(53);
2177                 s.sin6.sin6_addr = in6addr_any;
2178                 slen = sizeof(s.sin6);
2179         }
2180
2181         if (bind(sk, &s.sa, slen) < 0) {
2182                 connman_error("Failed to bind %s listener socket", proto);
2183                 close(sk);
2184                 return -EIO;
2185         }
2186
2187         if (protocol == IPPROTO_TCP && listen(sk, 10) < 0) {
2188                 connman_error("Failed to listen on TCP socket");
2189                 close(sk);
2190                 return -EIO;
2191         }
2192
2193         channel = g_io_channel_unix_new(sk);
2194         if (channel == NULL) {
2195                 connman_error("Failed to create %s listener channel", proto);
2196                 close(sk);
2197                 return -EIO;
2198         }
2199
2200         g_io_channel_set_close_on_unref(channel, TRUE);
2201
2202         if (protocol == IPPROTO_TCP) {
2203                 ifdata->tcp_listener_channel = channel;
2204                 ifdata->tcp_listener_watch = g_io_add_watch(channel,
2205                                 G_IO_IN, tcp_listener_event, (gpointer) ifdata);
2206         } else {
2207                 ifdata->udp_listener_channel = channel;
2208                 ifdata->udp_listener_watch = g_io_add_watch(channel,
2209                                 G_IO_IN, udp_listener_event, (gpointer) ifdata);
2210         }
2211
2212         return 0;
2213 }
2214
2215 static void destroy_udp_listener(struct listener_data *ifdata)
2216 {
2217         DBG("interface %s", ifdata->ifname);
2218
2219         if (ifdata->udp_listener_watch > 0)
2220                 g_source_remove(ifdata->udp_listener_watch);
2221
2222         g_io_channel_unref(ifdata->udp_listener_channel);
2223 }
2224
2225 static void destroy_tcp_listener(struct listener_data *ifdata)
2226 {
2227         DBG("interface %s", ifdata->ifname);
2228
2229         if (ifdata->tcp_listener_watch > 0)
2230                 g_source_remove(ifdata->tcp_listener_watch);
2231
2232         g_io_channel_unref(ifdata->tcp_listener_channel);
2233 }
2234
2235 static int create_listener(struct listener_data *ifdata)
2236 {
2237         int err;
2238
2239         err = create_dns_listener(IPPROTO_UDP, ifdata);
2240         if (err < 0)
2241                 return err;
2242
2243         err = create_dns_listener(IPPROTO_TCP, ifdata);
2244         if (err < 0) {
2245                 destroy_udp_listener(ifdata);
2246                 return err;
2247         }
2248
2249         if (g_strcmp0(ifdata->ifname, "lo") == 0)
2250                 __connman_resolvfile_append("lo", NULL, "127.0.0.1");
2251
2252         return 0;
2253 }
2254
2255 static void destroy_listener(struct listener_data *ifdata)
2256 {
2257         GSList *list;
2258
2259         if (g_strcmp0(ifdata->ifname, "lo") == 0)
2260                 __connman_resolvfile_remove("lo", NULL, "127.0.0.1");
2261
2262         for (list = request_pending_list; list; list = list->next) {
2263                 struct request_data *req = list->data;
2264
2265                 DBG("Dropping pending request (id 0x%04x -> 0x%04x)",
2266                                                 req->srcid, req->dstid);
2267
2268                 g_free(req->resp);
2269                 g_free(req->request);
2270                 g_free(req->name);
2271                 g_free(req);
2272                 list->data = NULL;
2273         }
2274
2275         g_slist_free(request_pending_list);
2276         request_pending_list = NULL;
2277
2278         for (list = request_list; list; list = list->next) {
2279                 struct request_data *req = list->data;
2280
2281                 DBG("Dropping request (id 0x%04x -> 0x%04x)",
2282                                                 req->srcid, req->dstid);
2283
2284                 g_free(req->resp);
2285                 g_free(req->request);
2286                 g_free(req->name);
2287                 g_free(req);
2288                 list->data = NULL;
2289         }
2290
2291         g_slist_free(request_list);
2292         request_list = NULL;
2293
2294         destroy_tcp_listener(ifdata);
2295         destroy_udp_listener(ifdata);
2296 }
2297
2298 int __connman_dnsproxy_add_listener(const char *interface)
2299 {
2300         struct listener_data *ifdata;
2301         int err;
2302
2303         DBG("interface %s", interface);
2304
2305         if (g_hash_table_lookup(listener_table, interface) != NULL)
2306                 return 0;
2307
2308         ifdata = g_try_new0(struct listener_data, 1);
2309         if (ifdata == NULL)
2310                 return -ENOMEM;
2311
2312         ifdata->ifname = g_strdup(interface);
2313         ifdata->udp_listener_channel = NULL;
2314         ifdata->udp_listener_watch = 0;
2315         ifdata->tcp_listener_channel = NULL;
2316         ifdata->tcp_listener_watch = 0;
2317
2318         err = create_listener(ifdata);
2319         if (err < 0) {
2320                 connman_error("Couldn't create listener for %s err %d",
2321                                 interface, err);
2322                 g_free(ifdata->ifname);
2323                 g_free(ifdata);
2324                 return err;
2325         }
2326         g_hash_table_insert(listener_table, ifdata->ifname, ifdata);
2327         return 0;
2328 }
2329
2330 void __connman_dnsproxy_remove_listener(const char *interface)
2331 {
2332         struct listener_data *ifdata;
2333
2334         DBG("interface %s", interface);
2335
2336         ifdata = g_hash_table_lookup(listener_table, interface);
2337         if (ifdata == NULL)
2338                 return;
2339
2340         destroy_listener(ifdata);
2341
2342         g_hash_table_remove(listener_table, interface);
2343 }
2344
2345 static void remove_listener(gpointer key, gpointer value, gpointer user_data)
2346 {
2347         __connman_dnsproxy_remove_listener(key);
2348 }
2349
2350 int __connman_dnsproxy_init(void)
2351 {
2352         int err;
2353
2354         DBG("");
2355
2356         listener_table = g_hash_table_new_full(g_str_hash, g_str_equal,
2357                                                         g_free, g_free);
2358         err = __connman_dnsproxy_add_listener("lo");
2359         if (err < 0)
2360                 return err;
2361
2362         err = connman_notifier_register(&dnsproxy_notifier);
2363         if (err < 0)
2364                 goto destroy;
2365
2366         return 0;
2367
2368 destroy:
2369         __connman_dnsproxy_remove_listener("lo");
2370         g_hash_table_destroy(listener_table);
2371
2372         return err;
2373 }
2374
2375 void __connman_dnsproxy_cleanup(void)
2376 {
2377         DBG("");
2378
2379         connman_notifier_unregister(&dnsproxy_notifier);
2380
2381         g_hash_table_foreach(listener_table, remove_listener, NULL);
2382
2383         g_hash_table_destroy(listener_table);
2384 }