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
  36 #include <glib.h>
  37
  38 #include "connman.h"
  39
  40 #if __BYTE_ORDER == __LITTLE_ENDIAN
  41 struct domain_hdr {
  42         uint16_t id;
  43         uint8_t rd:1;
  44         uint8_t tc:1;
  45         uint8_t aa:1;
  46         uint8_t opcode:4;
  47         uint8_t qr:1;
  48         uint8_t rcode:4;
  49         uint8_t z:3;
  50         uint8_t ra:1;
  51         uint16_t qdcount;
  52         uint16_t ancount;
  53         uint16_t nscount;
  54         uint16_t arcount;
  55 } __attribute__ ((packed));
  56 #elif __BYTE_ORDER == __BIG_ENDIAN
  57 struct domain_hdr {
  58         uint16_t id;
  59         uint8_t qr:1;
  60         uint8_t opcode:4;
  61         uint8_t aa:1;
  62         uint8_t tc:1;
  63         uint8_t rd:1;
  64         uint8_t ra:1;
  65         uint8_t z:3;
  66         uint8_t rcode:4;
  67         uint16_t qdcount;
  68         uint16_t ancount;
  69         uint16_t nscount;
  70         uint16_t arcount;
  71 } __attribute__ ((packed));
  72 #else
  73 #error "Unknown byte order"
  74 #endif
  75
  76 struct partial_reply {
  77         uint16_t len;
  78         uint16_t received;
  79         unsigned char buf[];
  80 };
  81
  82 struct server_data {
  83         char *interface;
  84         GList *domains;
  85         char *server;
  86         int protocol;
  87         GIOChannel *channel;
  88         guint watch;
  89         guint timeout;
  90         gboolean enabled;
  91         gboolean connected;
  92         struct partial_reply *incoming_reply;
  93 };
  94
  95 struct request_data {
  96         union {
  97                 struct sockaddr_in6 __sin6; /* Only for the length */
  98                 struct sockaddr sa;
  99         };
 100         socklen_t sa_len;
 101         int client_sk;
 102         int protocol;
 103         guint16 srcid;
 104         guint16 dstid;
 105         guint16 altid;
 106         guint timeout;
 107         guint watch;
 108         guint numserv;
 109         guint numresp;
 110         gpointer request;
 111         gsize request_len;
 112         gpointer name;
 113         gpointer resp;
 114         gsize resplen;
 115         struct listener_data *ifdata;
 116 };
 117
 118 struct listener_data {
 119         char *ifname;
 120         GIOChannel *udp_listener_channel;
 121         guint udp_listener_watch;
 122         GIOChannel *tcp_listener_channel;
 123         guint tcp_listener_watch;
 124 };
 125
 126 static GSList *server_list = NULL;
 127 static GSList *request_list = NULL;
 128 static GSList *request_pending_list = NULL;
 129 static guint16 request_id = 0x0000;
 130 static GHashTable *listener_table = NULL;
 131
 132 static int protocol_offset(int protocol)
 133 {
 134         switch (protocol) {
 135         case IPPROTO_UDP:
 136                 return 0;
 137
 138         case IPPROTO_TCP:
 139                 return 2;
 140
 141         default:
 142                 return -EINVAL;
 143         }
 144
 145 }
 146
 147 static struct request_data *find_request(guint16 id)
 148 {
 149         GSList *list;
 150
 151         for (list = request_list; list; list = list->next) {
 152                 struct request_data *req = list->data;
 153
 154                 if (req->dstid == id || req->altid == id)
 155                         return req;
 156         }
 157
 158         return NULL;
 159 }
 160
 161 static struct server_data *find_server(const char *interface,
 162                                         const char *server,
 163                                                 int protocol)
 164 {
 165         GSList *list;
 166
 167         DBG("interface %s server %s", interface, server);
 168
 169         for (list = server_list; list; list = list->next) {
 170                 struct server_data *data = list->data;
 171
 172                 if (interface == NULL && data->interface == NULL &&
 173                                 g_str_equal(data->server, server) == TRUE &&
 174                                 data->protocol == protocol)
 175                         return data;
 176
 177                 if (interface == NULL ||
 178                                 data->interface == NULL || data->server == NULL)
 179                         continue;
 180
 181                 if (g_str_equal(data->interface, interface) == TRUE &&
 182                                 g_str_equal(data->server, server) == TRUE &&
 183                                 data->protocol == protocol)
 184                         return data;
 185         }
 186
 187         return NULL;
 188 }
 189
 190
 191 static void send_response(int sk, unsigned char *buf, int len,
 192                                 const struct sockaddr *to, socklen_t tolen,
 193                                 int protocol)
 194 {
 195         struct domain_hdr *hdr;
 196         int err, offset = protocol_offset(protocol);
 197
 198         DBG("");
 199
 200         if (offset < 0)
 201                 return;
 202
 203         if (len < 12)
 204                 return;
 205
 206         hdr = (void *) (buf + offset);
 207
 208         DBG("id 0x%04x qr %d opcode %d", hdr->id, hdr->qr, hdr->opcode);
 209
 210         hdr->qr = 1;
 211         hdr->rcode = 2;
 212
 213         hdr->ancount = 0;
 214         hdr->nscount = 0;
 215         hdr->arcount = 0;
 216
 217         err = sendto(sk, buf, len, 0, to, tolen);
 218         if (err < 0)
 219                 return;
 220 }
 221
 222 static gboolean request_timeout(gpointer user_data)
 223 {
 224         struct request_data *req = user_data;
 225         struct listener_data *ifdata;
 226
 227         DBG("id 0x%04x", req->srcid);
 228
 229         if (req == NULL)
 230                 return FALSE;
 231
 232         ifdata = req->ifdata;
 233
 234         request_list = g_slist_remove(request_list, req);
 235         req->numserv--;
 236
 237         if (req->resplen > 0 && req->resp != NULL) {
 238                 int sk, err;
 239
 240                 sk = g_io_channel_unix_get_fd(ifdata->udp_listener_channel);
 241
 242                 err = sendto(sk, req->resp, req->resplen, 0,
 243                                                 &req->sa, req->sa_len);
 244                 if (err < 0)
 245                         return FALSE;
 246         } else if (req->request && req->numserv == 0) {
 247                 struct domain_hdr *hdr;
 248
 249                 if (req->protocol == IPPROTO_TCP) {
 250                         hdr = (void *) (req->request + 2);
 251                         hdr->id = req->srcid;
 252                         send_response(req->client_sk, req->request,
 253                                         req->request_len, NULL, 0, IPPROTO_TCP);
 254
 255                 } else if (req->protocol == IPPROTO_UDP) {
 256                         int sk;
 257
 258                         hdr = (void *) (req->request);
 259                         hdr->id = req->srcid;
 260                         sk = g_io_channel_unix_get_fd(
 261                                                 ifdata->udp_listener_channel);
 262                         send_response(sk, req->request, req->request_len,
 263                                         &req->sa, req->sa_len, IPPROTO_UDP);
 264                 }
 265         }
 266
 267         g_free(req->resp);
 268         g_free(req);
 269
 270         return FALSE;
 271 }
 272
 273 static int append_query(unsigned char *buf, unsigned int size,
 274                                 const char *query, const char *domain)
 275 {
 276         unsigned char *ptr = buf;
 277         char *offset;
 278
 279         DBG("query %s domain %s", query, domain);
 280
 281         offset = (char *) query;
 282         while (offset != NULL) {
 283                 char *tmp;
 284
 285                 tmp = strchr(offset, '.');
 286                 if (tmp == NULL) {
 287                         if (strlen(offset) == 0)
 288                                 break;
 289                         *ptr = strlen(offset);
 290                         memcpy(ptr + 1, offset, strlen(offset));
 291                         ptr += strlen(offset) + 1;
 292                         break;
 293                 }
 294
 295                 *ptr = tmp - offset;
 296                 memcpy(ptr + 1, offset, tmp - offset);
 297                 ptr += tmp - offset + 1;
 298
 299                 offset = tmp + 1;
 300         }
 301
 302         offset = (char *) domain;
 303         while (offset != NULL) {
 304                 char *tmp;
 305
 306                 tmp = strchr(offset, '.');
 307                 if (tmp == NULL) {
 308                         if (strlen(offset) == 0)
 309                                 break;
 310                         *ptr = strlen(offset);
 311                         memcpy(ptr + 1, offset, strlen(offset));
 312                         ptr += strlen(offset) + 1;
 313                         break;
 314                 }
 315
 316                 *ptr = tmp - offset;
 317                 memcpy(ptr + 1, offset, tmp - offset);
 318                 ptr += tmp - offset + 1;
 319
 320                 offset = tmp + 1;
 321         }
 322
 323         *ptr++ = 0x00;
 324
 325         return ptr - buf;
 326 }
 327
 328 static int ns_resolv(struct server_data *server, struct request_data *req,
 329                                 gpointer request, gpointer name)
 330 {
 331         GList *list;
 332         int sk, err;
 333         char *dot, *lookup = (char *) name;
 334
 335         sk = g_io_channel_unix_get_fd(server->channel);
 336
 337         err = send(sk, request, req->request_len, 0);
 338
 339         req->numserv++;
 340
 341         /* If we have more than one dot, we don't add domains */
 342         dot = strchr(lookup, '.');
 343         if (dot != NULL && dot != lookup + strlen(lookup) - 1)
 344                 return 0;
 345
 346         for (list = server->domains; list; list = list->next) {
 347                 char *domain;
 348                 unsigned char alt[1024];
 349                 struct domain_hdr *hdr = (void *) &alt;
 350                 int altlen, domlen, offset;
 351
 352                 domain = list->data;
 353
 354                 if (domain == NULL)
 355                         continue;
 356
 357                 offset = protocol_offset(server->protocol);
 358                 if (offset < 0)
 359                         return offset;
 360
 361                 domlen = strlen(domain) + 1;
 362                 if (domlen < 5)
 363                         return -EINVAL;
 364
 365                 alt[offset] = req->altid & 0xff;
 366                 alt[offset + 1] = req->altid >> 8;
 367
 368                 memcpy(alt + offset + 2, request + offset + 2, 10);
 369                 hdr->qdcount = htons(1);
 370
 371                 altlen = append_query(alt + offset + 12, sizeof(alt) - 12,
 372                                         name, domain);
 373                 if (altlen < 0)
 374                         return -EINVAL;
 375
 376                 altlen += 12;
 377
 378                 memcpy(alt + offset + altlen,
 379                         request + offset + altlen - domlen,
 380                                 req->request_len - altlen + domlen);
 381
 382                 if (server->protocol == IPPROTO_TCP) {
 383                         int req_len = req->request_len + domlen - 1;
 384
 385                         alt[0] = (req_len >> 8) & 0xff;
 386                         alt[1] = req_len & 0xff;
 387                 }
 388
 389                 err = send(sk, alt, req->request_len + domlen + 1, 0);
 390                 if (err < 0)
 391                         return -EIO;
 392
 393                 req->numserv++;
 394         }
 395
 396         return 0;
 397 }
 398
 399 static int forward_dns_reply(unsigned char *reply, int reply_len, int protocol)
 400 {
 401         struct domain_hdr *hdr;
 402         struct request_data *req;
 403         int dns_id, sk, err, offset = protocol_offset(protocol);
 404         struct listener_data *ifdata;
 405
 406         if (offset < 0)
 407                 return offset;
 408
 409         hdr = (void *)(reply + offset);
 410         dns_id = reply[offset] | reply[offset + 1] << 8;
 411
 412         DBG("Received %d bytes (id 0x%04x)", reply_len, dns_id);
 413
 414         req = find_request(dns_id);
 415         if (req == NULL)
 416                 return -EINVAL;
 417
 418         DBG("id 0x%04x rcode %d", hdr->id, hdr->rcode);
 419
 420         ifdata = req->ifdata;
 421
 422         reply[offset] = req->srcid & 0xff;
 423         reply[offset + 1] = req->srcid >> 8;
 424
 425         req->numresp++;
 426
 427         if (hdr->rcode == 0 || req->resp == NULL) {
 428                 g_free(req->resp);
 429                 req->resplen = 0;
 430
 431                 req->resp = g_try_malloc(reply_len);
 432                 if (req->resp == NULL)
 433                         return -ENOMEM;
 434
 435                 memcpy(req->resp, reply, reply_len);
 436                 req->resplen = reply_len;
 437         }
 438
 439         if (hdr->rcode > 0 && req->numresp < req->numserv)
 440                 return -EINVAL;
 441
 442         if (req->timeout > 0)
 443                 g_source_remove(req->timeout);
 444
 445         request_list = g_slist_remove(request_list, req);
 446
 447         if (protocol == IPPROTO_UDP) {
 448                 sk = g_io_channel_unix_get_fd(ifdata->udp_listener_channel);
 449                 err = sendto(sk, req->resp, req->resplen, 0,
 450                              &req->sa, req->sa_len);
 451         } else {
 452                 sk = req->client_sk;
 453                 err = send(sk, req->resp, req->resplen, 0);
 454                 close(sk);
 455         }
 456
 457         g_free(req->resp);
 458         g_free(req);
 459
 460         return err;
 461 }
 462
 463 static void destroy_server(struct server_data *server)
 464 {
 465         GList *list;
 466
 467         DBG("interface %s server %s", server->interface, server->server);
 468
 469         server_list = g_slist_remove(server_list, server);
 470
 471         if (server->watch > 0)
 472                 g_source_remove(server->watch);
 473
 474         if (server->timeout > 0)
 475                 g_source_remove(server->timeout);
 476
 477         g_io_channel_unref(server->channel);
 478
 479         if (server->protocol == IPPROTO_UDP)
 480                 connman_info("Removing DNS server %s", server->server);
 481
 482         g_free(server->incoming_reply);
 483         g_free(server->server);
 484         for (list = server->domains; list; list = list->next) {
 485                 char *domain = list->data;
 486
 487                 server->domains = g_list_remove(server->domains, domain);
 488                 g_free(domain);
 489         }
 490         g_free(server->interface);
 491         g_free(server);
 492 }
 493
 494 static gboolean udp_server_event(GIOChannel *channel, GIOCondition condition,
 495                                                         gpointer user_data)
 496 {
 497         unsigned char buf[4096];
 498         int sk, err, len;
 499
 500         if (condition & (G_IO_NVAL | G_IO_ERR | G_IO_HUP)) {
 501                 struct server_data *data = user_data;
 502
 503                 connman_error("Error with UDP server %s", data->server);
 504                 data->watch = 0;
 505                 return FALSE;
 506         }
 507
 508         sk = g_io_channel_unix_get_fd(channel);
 509
 510         len = recv(sk, buf, sizeof(buf), 0);
 511         if (len < 12)
 512                 return TRUE;
 513
 514         err = forward_dns_reply(buf, len, IPPROTO_UDP);
 515         if (err < 0)
 516                 return TRUE;
 517
 518         return TRUE;
 519 }
 520
 521 static gboolean tcp_server_event(GIOChannel *channel, GIOCondition condition,
 522                                                         gpointer user_data)
 523 {
 524         int sk;
 525         struct server_data *server = user_data;
 526
 527         sk = g_io_channel_unix_get_fd(channel);
 528         if (sk == 0)
 529                 return FALSE;
 530
 531         if (condition & (G_IO_NVAL | G_IO_ERR | G_IO_HUP)) {
 532                 GSList *list;
 533 hangup:
 534                 DBG("TCP server channel closed");
 535
 536                 /*
 537                  * Discard any partial response which is buffered; better
 538                  * to get a proper response from a working server.
 539                  */
 540                 g_free(server->incoming_reply);
 541                 server->incoming_reply = NULL;
 542
 543                 for (list = request_list; list; list = list->next) {
 544                         struct request_data *req = list->data;
 545                         struct domain_hdr *hdr;
 546
 547                         if (req->protocol == IPPROTO_UDP)
 548                                 continue;
 549
 550                         if (req->request == NULL)
 551                                 continue;
 552
 553                         /*
 554                          * If we're not waiting for any further response
 555                          * from another name server, then we send an error
 556                          * response to the client.
 557                          */
 558                         if (req->numserv && --(req->numserv))
 559                                 continue;
 560
 561                         hdr = (void *) (req->request + 2);
 562                         hdr->id = req->srcid;
 563                         send_response(req->client_sk, req->request,
 564                                         req->request_len, NULL, 0, IPPROTO_TCP);
 565
 566                         request_list = g_slist_remove(request_list, req);
 567                 }
 568
 569                 destroy_server(server);
 570
 571                 return FALSE;
 572         }
 573
 574         if ((condition & G_IO_OUT) && !server->connected) {
 575                 GSList *list;
 576                 GList *domains;
 577                 struct server_data *udp_server;
 578
 579                 udp_server = find_server(server->interface, server->server,
 580                                                                 IPPROTO_UDP);
 581                 if (udp_server != NULL) {
 582                         for (domains = udp_server->domains; domains;
 583                                                 domains = domains->next) {
 584                                 char *dom = domains->data;
 585
 586                                 DBG("Adding domain %s to %s",
 587                                                 dom, server->server);
 588
 589                                 server->domains = g_list_append(server->domains,
 590                                                                 g_strdup(dom));
 591                         }
 592                 }
 593
 594                 server->connected = TRUE;
 595                 server_list = g_slist_append(server_list, server);
 596
 597                 if (server->timeout > 0) {
 598                         g_source_remove(server->timeout);
 599                         server->timeout = 0;
 600                 }
 601
 602                 for (list = request_list; list; list = list->next) {
 603                         struct request_data *req = list->data;
 604
 605                         if (req->protocol == IPPROTO_UDP)
 606                                 continue;
 607
 608                         DBG("Sending req %s over TCP", (char *)req->name);
 609
 610                         if (req->timeout > 0)
 611                                 g_source_remove(req->timeout);
 612
 613                         req->timeout = g_timeout_add_seconds(30,
 614                                                 request_timeout, req);
 615                         ns_resolv(server, req, req->request, req->name);
 616                 }
 617
 618         } else if (condition & G_IO_IN) {
 619                 struct partial_reply *reply = server->incoming_reply;
 620                 int bytes_recv;
 621
 622                 if (!reply) {
 623                         unsigned char reply_len_buf[2];
 624                         uint16_t reply_len;
 625
 626                         bytes_recv = recv(sk, reply_len_buf, 2, MSG_PEEK);
 627                         if (!bytes_recv) {
 628                                 goto hangup;
 629                         } else if (bytes_recv < 0) {
 630                                 if (errno == EAGAIN || errno == EWOULDBLOCK)
 631                                         return TRUE;
 632
 633                                 connman_error("DNS proxy error %s",
 634                                                 strerror(errno));
 635                                 goto hangup;
 636                         } else if (bytes_recv < 2)
 637                                 return TRUE;
 638
 639                         reply_len = reply_len_buf[1] | reply_len_buf[0] << 8;
 640                         reply_len += 2;
 641
 642                         DBG("TCP reply %d bytes", reply_len);
 643
 644                         reply = g_try_malloc(sizeof(*reply) + reply_len + 2);
 645                         if (!reply)
 646                                 return TRUE;
 647
 648                         reply->len = reply_len;
 649                         reply->received = 0;
 650
 651                         server->incoming_reply = reply;
 652                 }
 653
 654                 while (reply->received < reply->len) {
 655                         bytes_recv = recv(sk, reply->buf + reply->received,
 656                                         reply->len - reply->received, 0);
 657                         if (!bytes_recv) {
 658                                 connman_error("DNS proxy TCP disconnect");
 659                                 break;
 660                         } else if (bytes_recv < 0) {
 661                                 if (errno == EAGAIN || errno == EWOULDBLOCK)
 662                                         return TRUE;
 663
 664                                 connman_error("DNS proxy error %s",
 665                                                 strerror(errno));
 666                                 break;
 667                         }
 668                         reply->received += bytes_recv;
 669                 }
 670
 671                 forward_dns_reply(reply->buf, reply->received, IPPROTO_TCP);
 672
 673                 g_free(reply);
 674                 server->incoming_reply = NULL;
 675
 676                 destroy_server(server);
 677
 678                 return FALSE;
 679         }
 680
 681         return TRUE;
 682 }
 683
 684 static gboolean tcp_idle_timeout(gpointer user_data)
 685 {
 686         struct server_data *server = user_data;
 687
 688         DBG("");
 689
 690         if (server == NULL)
 691                 return FALSE;
 692
 693         destroy_server(server);
 694
 695         return FALSE;
 696 }
 697
 698 static struct server_data *create_server(const char *interface,
 699                                         const char *domain, const char *server,
 700                                         int protocol)
 701 {
 702         struct addrinfo hints, *rp;
 703         struct server_data *data;
 704         int sk, ret;
 705
 706         DBG("interface %s server %s", interface, server);
 707
 708         memset(&hints, 0, sizeof(hints));
 709
 710         switch (protocol) {
 711         case IPPROTO_UDP:
 712                 hints.ai_socktype = SOCK_DGRAM;
 713                 break;
 714
 715         case IPPROTO_TCP:
 716                 hints.ai_socktype = SOCK_STREAM;
 717                 break;
 718
 719         default:
 720                 return NULL;
 721         }
 722         hints.ai_family = AF_UNSPEC;
 723         hints.ai_flags = AI_PASSIVE | AI_NUMERICSERV | AI_NUMERICHOST;
 724
 725         ret = getaddrinfo(server, "53", &hints, &rp);
 726         if (ret) {
 727                 connman_error("Failed to parse server %s address: %s\n",
 728                               server, gai_strerror(ret));
 729                 return NULL;
 730         }
 731         /* Do not blindly copy this code elsewhere; it doesn't loop over the
 732            results using ->ai_next as it should. That's OK in *this* case
 733            because it was a numeric lookup; we *know* there's only one. */
 734
 735         sk = socket(rp->ai_family, rp->ai_socktype, rp->ai_protocol);
 736         if (sk < 0) {
 737                 connman_error("Failed to create server %s socket", server);
 738                 freeaddrinfo(rp);
 739                 return NULL;
 740         }
 741
 742         if (interface != NULL) {
 743                 if (setsockopt(sk, SOL_SOCKET, SO_BINDTODEVICE,
 744                                 interface, strlen(interface) + 1) < 0) {
 745                         connman_error("Failed to bind server %s "
 746                                                 "to interface %s",
 747                                                         server, interface);
 748                         freeaddrinfo(rp);
 749                         close(sk);
 750                         return NULL;
 751                 }
 752         }
 753
 754         data = g_try_new0(struct server_data, 1);
 755         if (data == NULL) {
 756                 connman_error("Failed to allocate server %s data", server);
 757                 freeaddrinfo(rp);
 758                 close(sk);
 759                 return NULL;
 760         }
 761
 762         data->channel = g_io_channel_unix_new(sk);
 763         if (data->channel == NULL) {
 764                 connman_error("Failed to create server %s channel", server);
 765                 freeaddrinfo(rp);
 766                 close(sk);
 767                 g_free(data);
 768                 return NULL;
 769         }
 770
 771         g_io_channel_set_close_on_unref(data->channel, TRUE);
 772
 773         if (protocol == IPPROTO_TCP) {
 774                 g_io_channel_set_flags(data->channel, G_IO_FLAG_NONBLOCK, NULL);
 775                 data->watch = g_io_add_watch(data->channel,
 776                         G_IO_OUT | G_IO_IN | G_IO_HUP | G_IO_NVAL | G_IO_ERR,
 777                                                 tcp_server_event, data);
 778                 data->timeout = g_timeout_add_seconds(30, tcp_idle_timeout,
 779                                                                 data);
 780         } else
 781                 data->watch = g_io_add_watch(data->channel,
 782                         G_IO_IN | G_IO_NVAL | G_IO_ERR | G_IO_HUP,
 783                                                 udp_server_event, data);
 784
 785         data->interface = g_strdup(interface);
 786         if (domain)
 787                 data->domains = g_list_append(data->domains, g_strdup(domain));
 788         data->server = g_strdup(server);
 789         data->protocol = protocol;
 790
 791         ret = connect(sk, rp->ai_addr, rp->ai_addrlen);
 792         freeaddrinfo(rp);
 793         if (ret < 0) {
 794                 if ((protocol == IPPROTO_TCP && errno != EINPROGRESS) ||
 795                                 protocol == IPPROTO_UDP) {
 796                         GList *list;
 797
 798                         connman_error("Failed to connect to server %s", server);
 799                         if (data->watch > 0)
 800                                 g_source_remove(data->watch);
 801                         if (data->timeout > 0)
 802                                 g_source_remove(data->timeout);
 803
 804                         g_io_channel_unref(data->channel);
 805                         close(sk);
 806
 807                         g_free(data->server);
 808                         g_free(data->interface);
 809                         for (list = data->domains; list; list = list->next) {
 810                                 char *domain = list->data;
 811
 812                                 data->domains = g_list_remove(data->domains,
 813                                                                         domain);
 814                                 g_free(domain);
 815                         }
 816                         g_free(data);
 817                         return NULL;
 818                 }
 819         }
 820
 821         if (protocol == IPPROTO_UDP) {
 822                 /* Enable new servers by default */
 823                 data->enabled = TRUE;
 824                 connman_info("Adding DNS server %s", data->server);
 825
 826                 server_list = g_slist_append(server_list, data);
 827
 828                 return data;
 829         }
 830
 831         return NULL;
 832 }
 833
 834 static gboolean resolv(struct request_data *req,
 835                                 gpointer request, gpointer name)
 836 {
 837         GSList *list;
 838
 839         for (list = server_list; list; list = list->next) {
 840                 struct server_data *data = list->data;
 841
 842                 DBG("server %s enabled %d", data->server, data->enabled);
 843
 844                 if (data->enabled == FALSE)
 845                         continue;
 846
 847                 if (data->watch == 0 && data->protocol == IPPROTO_UDP)
 848                         data->watch = g_io_add_watch(data->channel,
 849                                 G_IO_IN | G_IO_NVAL | G_IO_ERR | G_IO_HUP,
 850                                                 udp_server_event, data);
 851
 852                 if (ns_resolv(data, req, request, name) < 0)
 853                         continue;
 854         }
 855
 856         return TRUE;
 857 }
 858
 859 static void append_domain(const char *interface, const char *domain)
 860 {
 861         GSList *list;
 862
 863         DBG("interface %s domain %s", interface, domain);
 864
 865         if (domain == NULL)
 866                 return;
 867
 868         for (list = server_list; list; list = list->next) {
 869                 struct server_data *data = list->data;
 870                 GList *dom_list;
 871                 char *dom;
 872                 gboolean dom_found = FALSE;
 873
 874                 if (data->interface == NULL)
 875                         continue;
 876
 877                 if (g_str_equal(data->interface, interface) == FALSE)
 878                         continue;
 879
 880                 for (dom_list = data->domains; dom_list;
 881                                 dom_list = dom_list->next) {
 882                         dom = dom_list->data;
 883
 884                         if (g_str_equal(dom, domain)) {
 885                                 dom_found = TRUE;
 886                                 break;
 887                         }
 888                 }
 889
 890                 if (dom_found == FALSE) {
 891                         data->domains =
 892                                 g_list_append(data->domains, g_strdup(domain));
 893                 }
 894         }
 895 }
 896
 897 int __connman_dnsproxy_append(const char *interface, const char *domain,
 898                                                         const char *server)
 899 {
 900         struct server_data *data;
 901
 902         DBG("interface %s server %s", interface, server);
 903
 904         if (server == NULL && domain == NULL)
 905                 return -EINVAL;
 906
 907         if (server == NULL) {
 908                 append_domain(interface, domain);
 909
 910                 return 0;
 911         }
 912
 913         if (g_str_equal(server, "127.0.0.1") == TRUE)
 914                 return -ENODEV;
 915
 916         data = find_server(interface, server, IPPROTO_UDP);
 917         if (data != NULL) {
 918                 append_domain(interface, domain);
 919                 return 0;
 920         }
 921
 922         data = create_server(interface, domain, server, IPPROTO_UDP);
 923         if (data == NULL)
 924                 return -EIO;
 925
 926         return 0;
 927 }
 928
 929 static void remove_server(const char *interface, const char *domain,
 930                         const char *server, int protocol)
 931 {
 932         struct server_data *data;
 933
 934         data = find_server(interface, server, protocol);
 935         if (data == NULL)
 936                 return;
 937
 938         destroy_server(data);
 939 }
 940
 941 int __connman_dnsproxy_remove(const char *interface, const char *domain,
 942                                                         const char *server)
 943 {
 944         DBG("interface %s server %s", interface, server);
 945
 946         if (server == NULL)
 947                 return -EINVAL;
 948
 949         if (g_str_equal(server, "127.0.0.1") == TRUE)
 950                 return -ENODEV;
 951
 952         remove_server(interface, domain, server, IPPROTO_UDP);
 953         remove_server(interface, domain, server, IPPROTO_TCP);
 954
 955         return 0;
 956 }
 957
 958 void __connman_dnsproxy_flush(void)
 959 {
 960         GSList *list;
 961
 962         list = request_pending_list;
 963         while (list) {
 964                 struct request_data *req = list->data;
 965
 966                 list = list->next;
 967
 968                 request_pending_list =
 969                                 g_slist_remove(request_pending_list, req);
 970                 resolv(req, req->request, req->name);
 971                 g_free(req->request);
 972                 g_free(req->name);
 973         }
 974 }
 975
 976 static void dnsproxy_offline_mode(connman_bool_t enabled)
 977 {
 978         GSList *list;
 979
 980         DBG("enabled %d", enabled);
 981
 982         for (list = server_list; list; list = list->next) {
 983                 struct server_data *data = list->data;
 984
 985                 if (enabled == FALSE) {
 986                         connman_info("Enabling DNS server %s", data->server);
 987                         data->enabled = TRUE;
 988                 } else {
 989                         connman_info("Disabling DNS server %s", data->server);
 990                         data->enabled = FALSE;
 991                 }
 992         }
 993 }
 994
 995 static void dnsproxy_default_changed(struct connman_service *service)
 996 {
 997         GSList *list;
 998         char *interface;
 999
1000         DBG("service %p", service);
1001
1002         if (service == NULL) {
1003                 /* When no services are active, then disable DNS proxying */
1004                 dnsproxy_offline_mode(TRUE);
1005                 return;
1006         }
1007
1008         interface = connman_service_get_interface(service);
1009         if (interface == NULL)
1010                 return;
1011
1012         for (list = server_list; list; list = list->next) {
1013                 struct server_data *data = list->data;
1014
1015                 if (g_strcmp0(data->interface, interface) == 0) {
1016                         connman_info("Enabling DNS server %s", data->server);
1017                         data->enabled = TRUE;
1018                 } else {
1019                         connman_info("Disabling DNS server %s", data->server);
1020                         data->enabled = FALSE;
1021                 }
1022         }
1023
1024         g_free(interface);
1025 }
1026
1027 static struct connman_notifier dnsproxy_notifier = {
1028         .name                   = "dnsproxy",
1029         .default_changed        = dnsproxy_default_changed,
1030         .offline_mode           = dnsproxy_offline_mode,
1031 };
1032
1033 static unsigned char opt_edns0_type[2] = { 0x00, 0x29 };
1034
1035 static int parse_request(unsigned char *buf, int len,
1036                                         char *name, unsigned int size)
1037 {
1038         struct domain_hdr *hdr = (void *) buf;
1039         uint16_t qdcount = ntohs(hdr->qdcount);
1040         uint16_t arcount = ntohs(hdr->arcount);
1041         unsigned char *ptr;
1042         char *last_label = NULL;
1043         unsigned int remain, used = 0;
1044
1045         if (len < 12)
1046                 return -EINVAL;
1047
1048         DBG("id 0x%04x qr %d opcode %d qdcount %d arcount %d",
1049                                         hdr->id, hdr->qr, hdr->opcode,
1050                                                         qdcount, arcount);
1051
1052         if (hdr->qr != 0 || qdcount != 1)
1053                 return -EINVAL;
1054
1055         memset(name, 0, size);
1056
1057         ptr = buf + sizeof(struct domain_hdr);
1058         remain = len - sizeof(struct domain_hdr);
1059
1060         while (remain > 0) {
1061                 uint8_t len = *ptr;
1062
1063                 if (len == 0x00) {
1064                         last_label = (char *) (ptr + 1);
1065                         break;
1066                 }
1067
1068                 if (used + len + 1 > size)
1069                         return -ENOBUFS;
1070
1071                 strncat(name, (char *) (ptr + 1), len);
1072                 strcat(name, ".");
1073
1074                 used += len + 1;
1075
1076                 ptr += len + 1;
1077                 remain -= len + 1;
1078         }
1079
1080         if (last_label && arcount && remain >= 9 && last_label[4] == 0 &&
1081                                 !memcmp(last_label + 5, opt_edns0_type, 2)) {
1082                 uint16_t edns0_bufsize;
1083
1084                 edns0_bufsize = last_label[7] << 8 | last_label[8];
1085
1086                 DBG("EDNS0 buffer size %u", edns0_bufsize);
1087
1088                 /* This is an evil hack until full TCP support has been
1089                  * implemented.
1090                  *
1091                  * Somtimes the EDNS0 request gets send with a too-small
1092                  * buffer size. Since glibc doesn't seem to crash when it
1093                  * gets a response biffer then it requested, just bump
1094                  * the buffer size up to 4KiB.
1095                  */
1096                 if (edns0_bufsize < 0x1000) {
1097                         last_label[7] = 0x10;
1098                         last_label[8] = 0x00;
1099                 }
1100         }
1101
1102         DBG("query %s", name);
1103
1104         return 0;
1105 }
1106
1107 static gboolean tcp_listener_event(GIOChannel *channel, GIOCondition condition,
1108                                                         gpointer user_data)
1109 {
1110         unsigned char buf[768];
1111         char query[512];
1112         struct request_data *req;
1113         struct server_data *server;
1114         int sk, client_sk, len, err;
1115         struct sockaddr_in6 client_addr;
1116         socklen_t client_addr_len = sizeof(client_addr);
1117         GSList *list;
1118         struct listener_data *ifdata = user_data;
1119
1120         DBG("condition 0x%x", condition);
1121
1122         if (condition & (G_IO_NVAL | G_IO_ERR | G_IO_HUP)) {
1123                 if (ifdata->tcp_listener_watch > 0)
1124                         g_source_remove(ifdata->tcp_listener_watch);
1125                 ifdata->tcp_listener_watch = 0;
1126
1127                 connman_error("Error with TCP listener channel");
1128
1129                 return FALSE;
1130         }
1131
1132         sk = g_io_channel_unix_get_fd(channel);
1133
1134         client_sk = accept(sk, (void *)&client_addr, &client_addr_len);
1135         if (client_sk < 0) {
1136                 connman_error("Accept failure on TCP listener");
1137                 ifdata->tcp_listener_watch = 0;
1138                 return FALSE;
1139         }
1140
1141         len = recv(client_sk, buf, sizeof(buf), 0);
1142         if (len < 2)
1143                 return TRUE;
1144
1145         DBG("Received %d bytes (id 0x%04x)", len, buf[2] | buf[3] << 8);
1146
1147         err = parse_request(buf + 2, len - 2, query, sizeof(query));
1148         if (err < 0 || (g_slist_length(server_list) == 0)) {
1149                 send_response(client_sk, buf, len, NULL, 0, IPPROTO_TCP);
1150                 return TRUE;
1151         }
1152
1153         req = g_try_new0(struct request_data, 1);
1154         if (req == NULL)
1155                 return TRUE;
1156
1157         memcpy(&req->sa, &client_addr, client_addr_len);
1158         req->sa_len = client_addr_len;
1159         req->client_sk = client_sk;
1160         req->protocol = IPPROTO_TCP;
1161
1162         request_id += 2;
1163         if (request_id == 0x0000 || request_id == 0xffff)
1164                 request_id += 2;
1165
1166         req->srcid = buf[2] | (buf[3] << 8);
1167         req->dstid = request_id;
1168         req->altid = request_id + 1;
1169         req->request_len = len;
1170
1171         buf[2] = req->dstid & 0xff;
1172         buf[3] = req->dstid >> 8;
1173
1174         req->numserv = 0;
1175         req->ifdata = (struct listener_data *) ifdata;
1176         request_list = g_slist_append(request_list, req);
1177
1178         for (list = server_list; list; list = list->next) {
1179                 struct server_data *data = list->data;
1180                 GList *domains;
1181
1182                 if (data->protocol != IPPROTO_UDP || data->enabled == FALSE)
1183                         continue;
1184
1185                 server = create_server(data->interface, NULL,
1186                                         data->server, IPPROTO_TCP);
1187
1188                 /*
1189                  * If server is NULL, we're not connected yet.
1190                  * Copy the relevant buffers and continue with
1191                  * the next nameserver.
1192                  * The request will actually be sent once we're
1193                  * properly connected over TCP to this nameserver.
1194                  */
1195                 if (server == NULL) {
1196                         req->request = g_try_malloc0(req->request_len);
1197                         if (req->request == NULL)
1198                                 return TRUE;
1199
1200                         memcpy(req->request, buf, req->request_len);
1201
1202                         req->name = g_try_malloc0(sizeof(query));
1203                         if (req->name == NULL) {
1204                                 g_free(req->request);
1205                                 return TRUE;
1206                         }
1207                         memcpy(req->name, query, sizeof(query));
1208
1209                         continue;
1210                 }
1211
1212                 if (req->timeout > 0)
1213                         g_source_remove(req->timeout);
1214
1215                 for (domains = data->domains; domains;
1216                                 domains = domains->next) {
1217                         char *dom = domains->data;
1218
1219                         DBG("Adding domain %s to %s", dom, server->server);
1220
1221                         server->domains = g_list_append(server->domains,
1222                                                 g_strdup(dom));
1223                 }
1224
1225                 req->timeout = g_timeout_add_seconds(30, request_timeout, req);
1226                 ns_resolv(server, req, buf, query);
1227         }
1228
1229         return TRUE;
1230 }
1231
1232 static gboolean udp_listener_event(GIOChannel *channel, GIOCondition condition,
1233                                                         gpointer user_data)
1234 {
1235         unsigned char buf[768];
1236         char query[512];
1237         struct request_data *req;
1238         struct sockaddr_in6 client_addr;
1239         socklen_t client_addr_len = sizeof(client_addr);
1240         int sk, err, len;
1241         struct listener_data *ifdata = user_data;
1242
1243         if (condition & (G_IO_NVAL | G_IO_ERR | G_IO_HUP)) {
1244                 connman_error("Error with UDP listener channel");
1245                 ifdata->udp_listener_watch = 0;
1246                 return FALSE;
1247         }
1248
1249         sk = g_io_channel_unix_get_fd(channel);
1250
1251         memset(&client_addr, 0, client_addr_len);
1252         len = recvfrom(sk, buf, sizeof(buf), 0, (void *)&client_addr,
1253                        &client_addr_len);
1254         if (len < 2)
1255                 return TRUE;
1256
1257         DBG("Received %d bytes (id 0x%04x)", len, buf[0] | buf[1] << 8);
1258
1259         err = parse_request(buf, len, query, sizeof(query));
1260         if (err < 0 || (g_slist_length(server_list) == 0)) {
1261                 send_response(sk, buf, len, (void *)&client_addr,
1262                               client_addr_len, IPPROTO_UDP);
1263                 return TRUE;
1264         }
1265
1266         req = g_try_new0(struct request_data, 1);
1267         if (req == NULL)
1268                 return TRUE;
1269
1270         memcpy(&req->sa, &client_addr, client_addr_len);
1271         req->sa_len = client_addr_len;
1272         req->client_sk = 0;
1273         req->protocol = IPPROTO_UDP;
1274
1275         request_id += 2;
1276         if (request_id == 0x0000 || request_id == 0xffff)
1277                 request_id += 2;
1278
1279         req->srcid = buf[0] | (buf[1] << 8);
1280         req->dstid = request_id;
1281         req->altid = request_id + 1;
1282         req->request_len = len;
1283
1284         buf[0] = req->dstid & 0xff;
1285         buf[1] = req->dstid >> 8;
1286
1287         req->numserv = 0;
1288         req->ifdata = (struct listener_data *) ifdata;
1289         req->timeout = g_timeout_add_seconds(5, request_timeout, req);
1290         request_list = g_slist_append(request_list, req);
1291
1292         return resolv(req, buf, query);
1293 }
1294
1295 static int create_dns_listener(int protocol, const char *ifname)
1296 {
1297         GIOChannel *channel;
1298         const char *proto;
1299         union {
1300                 struct sockaddr sa;
1301                 struct sockaddr_in6 sin6;
1302                 struct sockaddr_in sin;
1303         } s;
1304         socklen_t slen;
1305         int sk, type, v6only = 0;
1306         int family = AF_INET6;
1307         struct listener_data *ifdata;
1308
1309         DBG("interface %s", ifname);
1310
1311         ifdata = g_hash_table_lookup(listener_table, ifname);
1312         if (ifdata == NULL)
1313                 return -ENODEV;
1314
1315         switch (protocol) {
1316         case IPPROTO_UDP:
1317                 proto = "UDP";
1318                 type = SOCK_DGRAM;
1319                 break;
1320
1321         case IPPROTO_TCP:
1322                 proto = "TCP";
1323                 type = SOCK_STREAM;
1324                 break;
1325
1326         default:
1327                 return -EINVAL;
1328         }
1329
1330         sk = socket(family, type, protocol);
1331         if (sk < 0 && family == AF_INET6 && errno == EAFNOSUPPORT) {
1332                 connman_error("No IPv6 support; DNS proxy listening only on Legacy IP");
1333                 family = AF_INET;
1334                 sk = socket(family, type, protocol);
1335         }
1336         if (sk < 0) {
1337                 connman_error("Failed to create %s listener socket", proto);
1338                 return -EIO;
1339         }
1340
1341         if (setsockopt(sk, SOL_SOCKET, SO_BINDTODEVICE,
1342                                         ifname, strlen(ifname) + 1) < 0) {
1343                 connman_error("Failed to bind %s listener interface", proto);
1344                 close(sk);
1345                 return -EIO;
1346         }
1347         /* Ensure it accepts Legacy IP connections too */
1348         if (family == AF_INET6 &&
1349                         setsockopt(sk, SOL_IPV6, IPV6_V6ONLY,
1350                                         &v6only, sizeof(v6only)) < 0) {
1351                 connman_error("Failed to clear V6ONLY on %s listener socket",
1352                               proto);
1353                 close(sk);
1354                 return -EIO;
1355         }
1356
1357         if (family == AF_INET) {
1358                 memset(&s.sin, 0, sizeof(s.sin));
1359                 s.sin.sin_family = AF_INET;
1360                 s.sin.sin_port = htons(53);
1361                 s.sin.sin_addr.s_addr = htonl(INADDR_ANY);
1362                 slen = sizeof(s.sin);
1363         } else {
1364                 memset(&s.sin6, 0, sizeof(s.sin6));
1365                 s.sin6.sin6_family = AF_INET6;
1366                 s.sin6.sin6_port = htons(53);
1367                 s.sin6.sin6_addr = in6addr_any;
1368                 slen = sizeof(s.sin6);
1369         }
1370
1371         if (bind(sk, &s.sa, slen) < 0) {
1372                 connman_error("Failed to bind %s listener socket", proto);
1373                 close(sk);
1374                 return -EIO;
1375         }
1376
1377         if (protocol == IPPROTO_TCP && listen(sk, 10) < 0) {
1378                 connman_error("Failed to listen on TCP socket");
1379                 close(sk);
1380                 return -EIO;
1381         }
1382
1383         channel = g_io_channel_unix_new(sk);
1384         if (channel == NULL) {
1385                 connman_error("Failed to create %s listener channel", proto);
1386                 close(sk);
1387                 return -EIO;
1388         }
1389
1390         g_io_channel_set_close_on_unref(channel, TRUE);
1391
1392         if (protocol == IPPROTO_TCP) {
1393                 ifdata->tcp_listener_channel = channel;
1394                 ifdata->tcp_listener_watch = g_io_add_watch(channel,
1395                                 G_IO_IN, tcp_listener_event, (gpointer) ifdata);
1396         } else {
1397                 ifdata->udp_listener_channel = channel;
1398                 ifdata->udp_listener_watch = g_io_add_watch(channel,
1399                                 G_IO_IN, udp_listener_event, (gpointer) ifdata);
1400         }
1401
1402         return 0;
1403 }
1404
1405 static void destroy_udp_listener(const char *interface)
1406 {
1407         struct listener_data *ifdata;
1408
1409         DBG("interface %s", interface);
1410
1411         ifdata = g_hash_table_lookup(listener_table, interface);
1412         if (ifdata == NULL)
1413                 return;
1414
1415         if (ifdata->udp_listener_watch > 0)
1416                 g_source_remove(ifdata->udp_listener_watch);
1417
1418         g_io_channel_unref(ifdata->udp_listener_channel);
1419 }
1420
1421 static void destroy_tcp_listener(const char *interface)
1422 {
1423         struct listener_data *ifdata;
1424
1425         DBG("interface %s", interface);
1426
1427         ifdata = g_hash_table_lookup(listener_table, interface);
1428         if (ifdata == NULL)
1429                 return;
1430
1431         if (ifdata->tcp_listener_watch > 0)
1432                 g_source_remove(ifdata->tcp_listener_watch);
1433
1434         g_io_channel_unref(ifdata->tcp_listener_channel);
1435 }
1436
1437 static int create_listener(const char *interface)
1438 {
1439         int err;
1440
1441         err = create_dns_listener(IPPROTO_UDP, interface);
1442         if (err < 0)
1443                 return err;
1444
1445         err = create_dns_listener(IPPROTO_TCP, interface);
1446         if (err < 0) {
1447                 destroy_udp_listener(interface);
1448                 return err;
1449         }
1450
1451         if (g_strcmp0(interface, "lo") == 0)
1452                 __connman_resolvfile_append("lo", NULL, "127.0.0.1");
1453
1454         return 0;
1455 }
1456
1457 static void destroy_listener(const char *interface)
1458 {
1459         GSList *list;
1460
1461         if (interface == NULL)
1462                 return;
1463
1464         if (g_strcmp0(interface, "lo") == 0)
1465                 __connman_resolvfile_remove("lo", NULL, "127.0.0.1");
1466
1467         for (list = request_pending_list; list; list = list->next) {
1468                 struct request_data *req = list->data;
1469
1470                 DBG("Dropping pending request (id 0x%04x -> 0x%04x)",
1471                                                 req->srcid, req->dstid);
1472
1473                 g_free(req->resp);
1474                 g_free(req->request);
1475                 g_free(req->name);
1476                 g_free(req);
1477                 list->data = NULL;
1478         }
1479
1480         g_slist_free(request_pending_list);
1481         request_pending_list = NULL;
1482
1483         for (list = request_list; list; list = list->next) {
1484                 struct request_data *req = list->data;
1485
1486                 DBG("Dropping request (id 0x%04x -> 0x%04x)",
1487                                                 req->srcid, req->dstid);
1488
1489                 g_free(req->resp);
1490                 g_free(req->request);
1491                 g_free(req->name);
1492                 g_free(req);
1493                 list->data = NULL;
1494         }
1495
1496         g_slist_free(request_list);
1497         request_list = NULL;
1498
1499         destroy_tcp_listener(interface);
1500         destroy_udp_listener(interface);
1501 }
1502
1503 int __connman_dnsproxy_add_listener(const char *interface)
1504 {
1505         struct listener_data *ifdata;
1506         int err;
1507
1508         DBG("interface %s", interface);
1509
1510         if (g_hash_table_lookup(listener_table, interface) != NULL)
1511                 return 0;
1512
1513         ifdata = g_try_new0(struct listener_data, 1);
1514         if (ifdata == NULL)
1515                 return -ENOMEM;
1516
1517         ifdata->ifname = g_strdup(interface);
1518         ifdata->udp_listener_channel = NULL;
1519         ifdata->udp_listener_watch = 0;
1520         ifdata->tcp_listener_channel = NULL;
1521         ifdata->tcp_listener_watch = 0;
1522         g_hash_table_insert(listener_table, ifdata->ifname, ifdata);
1523
1524         err = create_listener(interface);
1525         if (err < 0)
1526                 return err;
1527         return 0;
1528 }
1529
1530 void __connman_dnsproxy_remove_listener(const char *interface)
1531 {
1532         DBG("interface %s", interface);
1533
1534         destroy_listener(interface);
1535
1536         g_hash_table_remove(listener_table, interface);
1537 }
1538
1539 static void remove_listener(gpointer key, gpointer value, gpointer user_data)
1540 {
1541         __connman_dnsproxy_remove_listener(key);
1542 }
1543
1544 int __connman_dnsproxy_init(void)
1545 {
1546         int err;
1547
1548         DBG("");
1549
1550         listener_table = g_hash_table_new_full(g_str_hash, g_str_equal,
1551                                                         g_free, g_free);
1552         err = __connman_dnsproxy_add_listener("lo");
1553         if (err < 0)
1554                 return err;
1555
1556         err = connman_notifier_register(&dnsproxy_notifier);
1557         if (err < 0)
1558                 goto destroy;
1559
1560         return 0;
1561
1562 destroy:
1563         __connman_dnsproxy_remove_listener("lo");
1564         g_hash_table_destroy(listener_table);
1565
1566         return err;
1567 }
1568
1569 void __connman_dnsproxy_cleanup(void)
1570 {
1571         DBG("");
1572
1573         connman_notifier_unregister(&dnsproxy_notifier);
1574
1575         g_hash_table_foreach(listener_table, remove_listener, NULL);
1576
1577         g_hash_table_destroy(listener_table);
1578 }