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         gboolean append_domain;
 117 };
 118
 119 struct listener_data {
 120         char *ifname;
 121         GIOChannel *udp_listener_channel;
 122         guint udp_listener_watch;
 123         GIOChannel *tcp_listener_channel;
 124         guint tcp_listener_watch;
 125 };
 126
 127 static GSList *server_list = NULL;
 128 static GSList *request_list = NULL;
 129 static GSList *request_pending_list = NULL;
 130 static guint16 request_id = 0x0000;
 131 static GHashTable *listener_table = NULL;
 132
 133 static int protocol_offset(int protocol)
 134 {
 135         switch (protocol) {
 136         case IPPROTO_UDP:
 137                 return 0;
 138
 139         case IPPROTO_TCP:
 140                 return 2;
 141
 142         default:
 143                 return -EINVAL;
 144         }
 145
 146 }
 147
 148 static struct request_data *find_request(guint16 id)
 149 {
 150         GSList *list;
 151
 152         for (list = request_list; list; list = list->next) {
 153                 struct request_data *req = list->data;
 154
 155                 if (req->dstid == id || req->altid == id)
 156                         return req;
 157         }
 158
 159         return NULL;
 160 }
 161
 162 static struct server_data *find_server(const char *interface,
 163                                         const char *server,
 164                                                 int protocol)
 165 {
 166         GSList *list;
 167
 168         DBG("interface %s server %s", interface, server);
 169
 170         for (list = server_list; list; list = list->next) {
 171                 struct server_data *data = list->data;
 172
 173                 if (interface == NULL && data->interface == NULL &&
 174                                 g_str_equal(data->server, server) == TRUE &&
 175                                 data->protocol == protocol)
 176                         return data;
 177
 178                 if (interface == NULL ||
 179                                 data->interface == NULL || data->server == NULL)
 180                         continue;
 181
 182                 if (g_str_equal(data->interface, interface) == TRUE &&
 183                                 g_str_equal(data->server, server) == TRUE &&
 184                                 data->protocol == protocol)
 185                         return data;
 186         }
 187
 188         return NULL;
 189 }
 190
 191
 192 static void send_response(int sk, unsigned char *buf, int len,
 193                                 const struct sockaddr *to, socklen_t tolen,
 194                                 int protocol)
 195 {
 196         struct domain_hdr *hdr;
 197         int err, offset = protocol_offset(protocol);
 198
 199         DBG("");
 200
 201         if (offset < 0)
 202                 return;
 203
 204         if (len < 12)
 205                 return;
 206
 207         hdr = (void *) (buf + offset);
 208
 209         DBG("id 0x%04x qr %d opcode %d", hdr->id, hdr->qr, hdr->opcode);
 210
 211         hdr->qr = 1;
 212         hdr->rcode = 2;
 213
 214         hdr->ancount = 0;
 215         hdr->nscount = 0;
 216         hdr->arcount = 0;
 217
 218         err = sendto(sk, buf, len, 0, to, tolen);
 219         if (err < 0) {
 220                 connman_error("Failed to send DNS response: %s",
 221                                 strerror(errno));
 222                 return;
 223         }
 224 }
 225
 226 static gboolean request_timeout(gpointer user_data)
 227 {
 228         struct request_data *req = user_data;
 229         struct listener_data *ifdata;
 230
 231         DBG("id 0x%04x", req->srcid);
 232
 233         if (req == NULL)
 234                 return FALSE;
 235
 236         ifdata = req->ifdata;
 237
 238         request_list = g_slist_remove(request_list, req);
 239         req->numserv--;
 240
 241         if (req->resplen > 0 && req->resp != NULL) {
 242                 int sk, err;
 243
 244                 sk = g_io_channel_unix_get_fd(ifdata->udp_listener_channel);
 245
 246                 err = sendto(sk, req->resp, req->resplen, 0,
 247                                                 &req->sa, req->sa_len);
 248                 if (err < 0)
 249                         return FALSE;
 250         } else if (req->request && req->numserv == 0) {
 251                 struct domain_hdr *hdr;
 252
 253                 if (req->protocol == IPPROTO_TCP) {
 254                         hdr = (void *) (req->request + 2);
 255                         hdr->id = req->srcid;
 256                         send_response(req->client_sk, req->request,
 257                                 req->request_len, NULL, 0, IPPROTO_TCP);
 258
 259                 } else if (req->protocol == IPPROTO_UDP) {
 260                         int sk;
 261
 262                         hdr = (void *) (req->request);
 263                         hdr->id = req->srcid;
 264                         sk = g_io_channel_unix_get_fd(
 265                                                 ifdata->udp_listener_channel);
 266                         send_response(sk, req->request, req->request_len,
 267                                         &req->sa, req->sa_len, IPPROTO_UDP);
 268                 }
 269         }
 270
 271         g_free(req->resp);
 272         g_free(req);
 273
 274         return FALSE;
 275 }
 276
 277 static int append_query(unsigned char *buf, unsigned int size,
 278                                 const char *query, const char *domain)
 279 {
 280         unsigned char *ptr = buf;
 281         char *offset;
 282         int len;
 283
 284         DBG("query %s domain %s", query, domain);
 285
 286         offset = (char *) query;
 287         while (offset != NULL) {
 288                 char *tmp;
 289
 290                 tmp = strchr(offset, '.');
 291                 if (tmp == NULL) {
 292                         len = strlen(offset);
 293                         if (len == 0)
 294                                 break;
 295                         *ptr = len;
 296                         memcpy(ptr + 1, offset, len);
 297                         ptr += len + 1;
 298                         break;
 299                 }
 300
 301                 *ptr = tmp - offset;
 302                 memcpy(ptr + 1, offset, tmp - offset);
 303                 ptr += tmp - offset + 1;
 304
 305                 offset = tmp + 1;
 306         }
 307
 308         offset = (char *) domain;
 309         while (offset != NULL) {
 310                 char *tmp;
 311
 312                 tmp = strchr(offset, '.');
 313                 if (tmp == NULL) {
 314                         len = strlen(offset);
 315                         if (len == 0)
 316                                 break;
 317                         *ptr = len;
 318                         memcpy(ptr + 1, offset, len);
 319                         ptr += len + 1;
 320                         break;
 321                 }
 322
 323                 *ptr = tmp - offset;
 324                 memcpy(ptr + 1, offset, tmp - offset);
 325                 ptr += tmp - offset + 1;
 326
 327                 offset = tmp + 1;
 328         }
 329
 330         *ptr++ = 0x00;
 331
 332         return ptr - buf;
 333 }
 334
 335 static int ns_resolv(struct server_data *server, struct request_data *req,
 336                                 gpointer request, gpointer name)
 337 {
 338         GList *list;
 339         int sk, err;
 340         char *dot, *lookup = (char *) name;
 341
 342         sk = g_io_channel_unix_get_fd(server->channel);
 343
 344         err = send(sk, request, req->request_len, 0);
 345
 346         req->numserv++;
 347
 348         /* If we have more than one dot, we don't add domains */
 349         dot = strchr(lookup, '.');
 350         if (dot != NULL && dot != lookup + strlen(lookup) - 1)
 351                 return 0;
 352
 353         if (server->domains != NULL && server->domains->data != NULL)
 354                 req->append_domain = TRUE;
 355
 356         for (list = server->domains; list; list = list->next) {
 357                 char *domain;
 358                 unsigned char alt[1024];
 359                 struct domain_hdr *hdr = (void *) &alt;
 360                 int altlen, domlen, offset;
 361
 362                 domain = list->data;
 363
 364                 if (domain == NULL)
 365                         continue;
 366
 367                 offset = protocol_offset(server->protocol);
 368                 if (offset < 0)
 369                         return offset;
 370
 371                 domlen = strlen(domain) + 1;
 372                 if (domlen < 5)
 373                         return -EINVAL;
 374
 375                 alt[offset] = req->altid & 0xff;
 376                 alt[offset + 1] = req->altid >> 8;
 377
 378                 memcpy(alt + offset + 2, request + offset + 2, 10);
 379                 hdr->qdcount = htons(1);
 380
 381                 altlen = append_query(alt + offset + 12, sizeof(alt) - 12,
 382                                         name, domain);
 383                 if (altlen < 0)
 384                         return -EINVAL;
 385
 386                 altlen += 12;
 387
 388                 memcpy(alt + offset + altlen,
 389                         request + offset + altlen - domlen,
 390                                 req->request_len - altlen - offset + domlen);
 391
 392                 if (server->protocol == IPPROTO_TCP) {
 393                         int req_len = req->request_len + domlen - 2;
 394
 395                         alt[0] = (req_len >> 8) & 0xff;
 396                         alt[1] = req_len & 0xff;
 397                 }
 398
 399                 err = send(sk, alt, req->request_len + domlen, 0);
 400                 if (err < 0)
 401                         return -EIO;
 402
 403                 req->numserv++;
 404         }
 405
 406         return 0;
 407 }
 408
 409 static int forward_dns_reply(unsigned char *reply, int reply_len, int protocol)
 410 {
 411         struct domain_hdr *hdr;
 412         struct request_data *req;
 413         int dns_id, sk, err, offset = protocol_offset(protocol);
 414         struct listener_data *ifdata;
 415
 416         if (offset < 0)
 417                 return offset;
 418
 419         hdr = (void *)(reply + offset);
 420         dns_id = reply[offset] | reply[offset + 1] << 8;
 421
 422         DBG("Received %d bytes (id 0x%04x)", reply_len, dns_id);
 423
 424         req = find_request(dns_id);
 425         if (req == NULL)
 426                 return -EINVAL;
 427
 428         DBG("id 0x%04x rcode %d", hdr->id, hdr->rcode);
 429
 430         ifdata = req->ifdata;
 431
 432         reply[offset] = req->srcid & 0xff;
 433         reply[offset + 1] = req->srcid >> 8;
 434
 435         req->numresp++;
 436
 437         if (hdr->rcode == 0 || req->resp == NULL) {
 438
 439                 /*
 440                  * If the domain name was append
 441                  * remove it before forwarding the reply.
 442                  */
 443                 if (req->append_domain == TRUE) {
 444                         unsigned char *ptr;
 445                         uint8_t host_len;
 446                         unsigned int domain_len;
 447
 448                         /*
 449                          * ptr points to the first char of the hostname.
 450                          * ->hostname.domain.net
 451                          */
 452                         ptr = reply + offset + sizeof(struct domain_hdr);
 453                         host_len = *ptr;
 454                         domain_len = strlen((const char *)ptr) - host_len - 1;
 455
 456                         /*
 457                          * remove the domain name and replaced it by the end
 458                          * of reply.
 459                          */
 460                         memmove(ptr + host_len + 1,
 461                                 ptr + host_len + domain_len + 1,
 462                                 reply_len - (ptr - reply + domain_len));
 463
 464                         reply_len = reply_len - domain_len;
 465                 }
 466
 467                 g_free(req->resp);
 468                 req->resplen = 0;
 469
 470                 req->resp = g_try_malloc(reply_len);
 471                 if (req->resp == NULL)
 472                         return -ENOMEM;
 473
 474                 memcpy(req->resp, reply, reply_len);
 475                 req->resplen = reply_len;
 476         }
 477
 478         if (hdr->rcode > 0 && req->numresp < req->numserv)
 479                 return -EINVAL;
 480
 481         if (req->timeout > 0)
 482                 g_source_remove(req->timeout);
 483
 484         request_list = g_slist_remove(request_list, req);
 485
 486         if (protocol == IPPROTO_UDP) {
 487                 sk = g_io_channel_unix_get_fd(ifdata->udp_listener_channel);
 488                 err = sendto(sk, req->resp, req->resplen, 0,
 489                              &req->sa, req->sa_len);
 490         } else {
 491                 sk = req->client_sk;
 492                 err = send(sk, req->resp, req->resplen, 0);
 493                 close(sk);
 494         }
 495
 496         g_free(req->resp);
 497         g_free(req);
 498
 499         return err;
 500 }
 501
 502 static void destroy_server(struct server_data *server)
 503 {
 504         GList *list;
 505
 506         DBG("interface %s server %s", server->interface, server->server);
 507
 508         server_list = g_slist_remove(server_list, server);
 509
 510         if (server->watch > 0)
 511                 g_source_remove(server->watch);
 512
 513         if (server->timeout > 0)
 514                 g_source_remove(server->timeout);
 515
 516         g_io_channel_unref(server->channel);
 517
 518         if (server->protocol == IPPROTO_UDP)
 519                 connman_info("Removing DNS server %s", server->server);
 520
 521         g_free(server->incoming_reply);
 522         g_free(server->server);
 523         for (list = server->domains; list; list = list->next) {
 524                 char *domain = list->data;
 525
 526                 server->domains = g_list_remove(server->domains, domain);
 527                 g_free(domain);
 528         }
 529         g_free(server->interface);
 530         g_free(server);
 531 }
 532
 533 static gboolean udp_server_event(GIOChannel *channel, GIOCondition condition,
 534                                                         gpointer user_data)
 535 {
 536         unsigned char buf[4096];
 537         int sk, err, len;
 538
 539         if (condition & (G_IO_NVAL | G_IO_ERR | G_IO_HUP)) {
 540                 struct server_data *data = user_data;
 541
 542                 connman_error("Error with UDP server %s", data->server);
 543                 data->watch = 0;
 544                 return FALSE;
 545         }
 546
 547         sk = g_io_channel_unix_get_fd(channel);
 548
 549         len = recv(sk, buf, sizeof(buf), 0);
 550         if (len < 12)
 551                 return TRUE;
 552
 553         err = forward_dns_reply(buf, len, IPPROTO_UDP);
 554         if (err < 0)
 555                 return TRUE;
 556
 557         return TRUE;
 558 }
 559
 560 static gboolean tcp_server_event(GIOChannel *channel, GIOCondition condition,
 561                                                         gpointer user_data)
 562 {
 563         int sk;
 564         struct server_data *server = user_data;
 565
 566         sk = g_io_channel_unix_get_fd(channel);
 567         if (sk == 0)
 568                 return FALSE;
 569
 570         if (condition & (G_IO_NVAL | G_IO_ERR | G_IO_HUP)) {
 571                 GSList *list;
 572 hangup:
 573                 DBG("TCP server channel closed");
 574
 575                 /*
 576                  * Discard any partial response which is buffered; better
 577                  * to get a proper response from a working server.
 578                  */
 579                 g_free(server->incoming_reply);
 580                 server->incoming_reply = NULL;
 581
 582                 for (list = request_list; list; list = list->next) {
 583                         struct request_data *req = list->data;
 584                         struct domain_hdr *hdr;
 585
 586                         if (req->protocol == IPPROTO_UDP)
 587                                 continue;
 588
 589                         if (req->request == NULL)
 590                                 continue;
 591
 592                         /*
 593                          * If we're not waiting for any further response
 594                          * from another name server, then we send an error
 595                          * response to the client.
 596                          */
 597                         if (req->numserv && --(req->numserv))
 598                                 continue;
 599
 600                         hdr = (void *) (req->request + 2);
 601                         hdr->id = req->srcid;
 602                         send_response(req->client_sk, req->request,
 603                                 req->request_len, NULL, 0, IPPROTO_TCP);
 604
 605                         request_list = g_slist_remove(request_list, req);
 606                 }
 607
 608                 destroy_server(server);
 609
 610                 return FALSE;
 611         }
 612
 613         if ((condition & G_IO_OUT) && !server->connected) {
 614                 GSList *list;
 615                 GList *domains;
 616                 struct server_data *udp_server;
 617
 618                 udp_server = find_server(server->interface, server->server,
 619                                                                 IPPROTO_UDP);
 620                 if (udp_server != NULL) {
 621                         for (domains = udp_server->domains; domains;
 622                                                 domains = domains->next) {
 623                                 char *dom = domains->data;
 624
 625                                 DBG("Adding domain %s to %s",
 626                                                 dom, server->server);
 627
 628                                 server->domains = g_list_append(server->domains,
 629                                                                 g_strdup(dom));
 630                         }
 631                 }
 632
 633                 server->connected = TRUE;
 634                 server_list = g_slist_append(server_list, server);
 635
 636                 if (server->timeout > 0) {
 637                         g_source_remove(server->timeout);
 638                         server->timeout = 0;
 639                 }
 640
 641                 for (list = request_list; list; list = list->next) {
 642                         struct request_data *req = list->data;
 643
 644                         if (req->protocol == IPPROTO_UDP)
 645                                 continue;
 646
 647                         DBG("Sending req %s over TCP", (char *)req->name);
 648
 649                         if (req->timeout > 0)
 650                                 g_source_remove(req->timeout);
 651
 652                         req->timeout = g_timeout_add_seconds(30,
 653                                                 request_timeout, req);
 654                         ns_resolv(server, req, req->request, req->name);
 655                 }
 656
 657         } else if (condition & G_IO_IN) {
 658                 struct partial_reply *reply = server->incoming_reply;
 659                 int bytes_recv;
 660
 661                 if (!reply) {
 662                         unsigned char reply_len_buf[2];
 663                         uint16_t reply_len;
 664
 665                         bytes_recv = recv(sk, reply_len_buf, 2, MSG_PEEK);
 666                         if (!bytes_recv) {
 667                                 goto hangup;
 668                         } else if (bytes_recv < 0) {
 669                                 if (errno == EAGAIN || errno == EWOULDBLOCK)
 670                                         return TRUE;
 671
 672                                 connman_error("DNS proxy error %s",
 673                                                 strerror(errno));
 674                                 goto hangup;
 675                         } else if (bytes_recv < 2)
 676                                 return TRUE;
 677
 678                         reply_len = reply_len_buf[1] | reply_len_buf[0] << 8;
 679                         reply_len += 2;
 680
 681                         DBG("TCP reply %d bytes", reply_len);
 682
 683                         reply = g_try_malloc(sizeof(*reply) + reply_len + 2);
 684                         if (!reply)
 685                                 return TRUE;
 686
 687                         reply->len = reply_len;
 688                         reply->received = 0;
 689
 690                         server->incoming_reply = reply;
 691                 }
 692
 693                 while (reply->received < reply->len) {
 694                         bytes_recv = recv(sk, reply->buf + reply->received,
 695                                         reply->len - reply->received, 0);
 696                         if (!bytes_recv) {
 697                                 connman_error("DNS proxy TCP disconnect");
 698                                 break;
 699                         } else if (bytes_recv < 0) {
 700                                 if (errno == EAGAIN || errno == EWOULDBLOCK)
 701                                         return TRUE;
 702
 703                                 connman_error("DNS proxy error %s",
 704                                                 strerror(errno));
 705                                 break;
 706                         }
 707                         reply->received += bytes_recv;
 708                 }
 709
 710                 forward_dns_reply(reply->buf, reply->received, IPPROTO_TCP);
 711
 712                 g_free(reply);
 713                 server->incoming_reply = NULL;
 714
 715                 destroy_server(server);
 716
 717                 return FALSE;
 718         }
 719
 720         return TRUE;
 721 }
 722
 723 static gboolean tcp_idle_timeout(gpointer user_data)
 724 {
 725         struct server_data *server = user_data;
 726
 727         DBG("");
 728
 729         if (server == NULL)
 730                 return FALSE;
 731
 732         destroy_server(server);
 733
 734         return FALSE;
 735 }
 736
 737 static struct server_data *create_server(const char *interface,
 738                                         const char *domain, const char *server,
 739                                         int protocol)
 740 {
 741         struct addrinfo hints, *rp;
 742         struct server_data *data;
 743         int sk, ret;
 744
 745         DBG("interface %s server %s", interface, server);
 746
 747         memset(&hints, 0, sizeof(hints));
 748
 749         switch (protocol) {
 750         case IPPROTO_UDP:
 751                 hints.ai_socktype = SOCK_DGRAM;
 752                 break;
 753
 754         case IPPROTO_TCP:
 755                 hints.ai_socktype = SOCK_STREAM;
 756                 break;
 757
 758         default:
 759                 return NULL;
 760         }
 761         hints.ai_family = AF_UNSPEC;
 762         hints.ai_flags = AI_PASSIVE | AI_NUMERICSERV | AI_NUMERICHOST;
 763
 764         ret = getaddrinfo(server, "53", &hints, &rp);
 765         if (ret) {
 766                 connman_error("Failed to parse server %s address: %s\n",
 767                               server, gai_strerror(ret));
 768                 return NULL;
 769         }
 770         /* Do not blindly copy this code elsewhere; it doesn't loop over the
 771            results using ->ai_next as it should. That's OK in *this* case
 772            because it was a numeric lookup; we *know* there's only one. */
 773
 774         sk = socket(rp->ai_family, rp->ai_socktype, rp->ai_protocol);
 775         if (sk < 0) {
 776                 connman_error("Failed to create server %s socket", server);
 777                 freeaddrinfo(rp);
 778                 return NULL;
 779         }
 780
 781         if (interface != NULL) {
 782                 if (setsockopt(sk, SOL_SOCKET, SO_BINDTODEVICE,
 783                                 interface, strlen(interface) + 1) < 0) {
 784                         connman_error("Failed to bind server %s "
 785                                                 "to interface %s",
 786                                                         server, interface);
 787                         freeaddrinfo(rp);
 788                         close(sk);
 789                         return NULL;
 790                 }
 791         }
 792
 793         data = g_try_new0(struct server_data, 1);
 794         if (data == NULL) {
 795                 connman_error("Failed to allocate server %s data", server);
 796                 freeaddrinfo(rp);
 797                 close(sk);
 798                 return NULL;
 799         }
 800
 801         data->channel = g_io_channel_unix_new(sk);
 802         if (data->channel == NULL) {
 803                 connman_error("Failed to create server %s channel", server);
 804                 freeaddrinfo(rp);
 805                 close(sk);
 806                 g_free(data);
 807                 return NULL;
 808         }
 809
 810         g_io_channel_set_close_on_unref(data->channel, TRUE);
 811
 812         if (protocol == IPPROTO_TCP) {
 813                 g_io_channel_set_flags(data->channel, G_IO_FLAG_NONBLOCK, NULL);
 814                 data->watch = g_io_add_watch(data->channel,
 815                         G_IO_OUT | G_IO_IN | G_IO_HUP | G_IO_NVAL | G_IO_ERR,
 816                                                 tcp_server_event, data);
 817                 data->timeout = g_timeout_add_seconds(30, tcp_idle_timeout,
 818                                                                 data);
 819         } else
 820                 data->watch = g_io_add_watch(data->channel,
 821                         G_IO_IN | G_IO_NVAL | G_IO_ERR | G_IO_HUP,
 822                                                 udp_server_event, data);
 823
 824         data->interface = g_strdup(interface);
 825         if (domain)
 826                 data->domains = g_list_append(data->domains, g_strdup(domain));
 827         data->server = g_strdup(server);
 828         data->protocol = protocol;
 829
 830         ret = connect(sk, rp->ai_addr, rp->ai_addrlen);
 831         freeaddrinfo(rp);
 832         if (ret < 0) {
 833                 if ((protocol == IPPROTO_TCP && errno != EINPROGRESS) ||
 834                                 protocol == IPPROTO_UDP) {
 835                         GList *list;
 836
 837                         connman_error("Failed to connect to server %s", server);
 838                         if (data->watch > 0)
 839                                 g_source_remove(data->watch);
 840                         if (data->timeout > 0)
 841                                 g_source_remove(data->timeout);
 842
 843                         g_io_channel_unref(data->channel);
 844                         close(sk);
 845
 846                         g_free(data->server);
 847                         g_free(data->interface);
 848                         for (list = data->domains; list; list = list->next) {
 849                                 char *domain = list->data;
 850
 851                                 data->domains = g_list_remove(data->domains,
 852                                                                         domain);
 853                                 g_free(domain);
 854                         }
 855                         g_free(data);
 856                         return NULL;
 857                 }
 858         }
 859
 860         if (protocol == IPPROTO_UDP) {
 861                 /* Enable new servers by default */
 862                 data->enabled = TRUE;
 863                 connman_info("Adding DNS server %s", data->server);
 864
 865                 server_list = g_slist_append(server_list, data);
 866
 867                 return data;
 868         }
 869
 870         return NULL;
 871 }
 872
 873 static gboolean resolv(struct request_data *req,
 874                                 gpointer request, gpointer name)
 875 {
 876         GSList *list;
 877
 878         for (list = server_list; list; list = list->next) {
 879                 struct server_data *data = list->data;
 880
 881                 DBG("server %s enabled %d", data->server, data->enabled);
 882
 883                 if (data->enabled == FALSE)
 884                         continue;
 885
 886                 if (data->watch == 0 && data->protocol == IPPROTO_UDP)
 887                         data->watch = g_io_add_watch(data->channel,
 888                                 G_IO_IN | G_IO_NVAL | G_IO_ERR | G_IO_HUP,
 889                                                 udp_server_event, data);
 890
 891                 if (ns_resolv(data, req, request, name) < 0)
 892                         continue;
 893         }
 894
 895         return TRUE;
 896 }
 897
 898 static void append_domain(const char *interface, const char *domain)
 899 {
 900         GSList *list;
 901
 902         DBG("interface %s domain %s", interface, domain);
 903
 904         if (domain == NULL)
 905                 return;
 906
 907         for (list = server_list; list; list = list->next) {
 908                 struct server_data *data = list->data;
 909                 GList *dom_list;
 910                 char *dom;
 911                 gboolean dom_found = FALSE;
 912
 913                 if (data->interface == NULL)
 914                         continue;
 915
 916                 if (g_str_equal(data->interface, interface) == FALSE)
 917                         continue;
 918
 919                 for (dom_list = data->domains; dom_list;
 920                                 dom_list = dom_list->next) {
 921                         dom = dom_list->data;
 922
 923                         if (g_str_equal(dom, domain)) {
 924                                 dom_found = TRUE;
 925                                 break;
 926                         }
 927                 }
 928
 929                 if (dom_found == FALSE) {
 930                         data->domains =
 931                                 g_list_append(data->domains, g_strdup(domain));
 932                 }
 933         }
 934 }
 935
 936 int __connman_dnsproxy_append(const char *interface, const char *domain,
 937                                                         const char *server)
 938 {
 939         struct server_data *data;
 940
 941         DBG("interface %s server %s", interface, server);
 942
 943         if (server == NULL && domain == NULL)
 944                 return -EINVAL;
 945
 946         if (server == NULL) {
 947                 append_domain(interface, domain);
 948
 949                 return 0;
 950         }
 951
 952         if (g_str_equal(server, "127.0.0.1") == TRUE)
 953                 return -ENODEV;
 954
 955         data = find_server(interface, server, IPPROTO_UDP);
 956         if (data != NULL) {
 957                 append_domain(interface, domain);
 958                 return 0;
 959         }
 960
 961         data = create_server(interface, domain, server, IPPROTO_UDP);
 962         if (data == NULL)
 963                 return -EIO;
 964
 965         return 0;
 966 }
 967
 968 static void remove_server(const char *interface, const char *domain,
 969                         const char *server, int protocol)
 970 {
 971         struct server_data *data;
 972
 973         data = find_server(interface, server, protocol);
 974         if (data == NULL)
 975                 return;
 976
 977         destroy_server(data);
 978 }
 979
 980 int __connman_dnsproxy_remove(const char *interface, const char *domain,
 981                                                         const char *server)
 982 {
 983         DBG("interface %s server %s", interface, server);
 984
 985         if (server == NULL)
 986                 return -EINVAL;
 987
 988         if (g_str_equal(server, "127.0.0.1") == TRUE)
 989                 return -ENODEV;
 990
 991         remove_server(interface, domain, server, IPPROTO_UDP);
 992         remove_server(interface, domain, server, IPPROTO_TCP);
 993
 994         return 0;
 995 }
 996
 997 void __connman_dnsproxy_flush(void)
 998 {
 999         GSList *list;
1000
1001         list = request_pending_list;
1002         while (list) {
1003                 struct request_data *req = list->data;
1004
1005                 list = list->next;
1006
1007                 request_pending_list =
1008                                 g_slist_remove(request_pending_list, req);
1009                 resolv(req, req->request, req->name);
1010                 g_free(req->request);
1011                 g_free(req->name);
1012         }
1013 }
1014
1015 static void dnsproxy_offline_mode(connman_bool_t enabled)
1016 {
1017         GSList *list;
1018
1019         DBG("enabled %d", enabled);
1020
1021         for (list = server_list; list; list = list->next) {
1022                 struct server_data *data = list->data;
1023
1024                 if (enabled == FALSE) {
1025                         connman_info("Enabling DNS server %s", data->server);
1026                         data->enabled = TRUE;
1027                 } else {
1028                         connman_info("Disabling DNS server %s", data->server);
1029                         data->enabled = FALSE;
1030                 }
1031         }
1032 }
1033
1034 static void dnsproxy_default_changed(struct connman_service *service)
1035 {
1036         GSList *list;
1037         char *interface;
1038
1039         DBG("service %p", service);
1040
1041         if (service == NULL) {
1042                 /* When no services are active, then disable DNS proxying */
1043                 dnsproxy_offline_mode(TRUE);
1044                 return;
1045         }
1046
1047         interface = connman_service_get_interface(service);
1048         if (interface == NULL)
1049                 return;
1050
1051         for (list = server_list; list; list = list->next) {
1052                 struct server_data *data = list->data;
1053
1054                 if (g_strcmp0(data->interface, interface) == 0) {
1055                         connman_info("Enabling DNS server %s", data->server);
1056                         data->enabled = TRUE;
1057                 } else {
1058                         connman_info("Disabling DNS server %s", data->server);
1059                         data->enabled = FALSE;
1060                 }
1061         }
1062
1063         g_free(interface);
1064 }
1065
1066 static struct connman_notifier dnsproxy_notifier = {
1067         .name                   = "dnsproxy",
1068         .default_changed        = dnsproxy_default_changed,
1069         .offline_mode           = dnsproxy_offline_mode,
1070 };
1071
1072 static unsigned char opt_edns0_type[2] = { 0x00, 0x29 };
1073
1074 static int parse_request(unsigned char *buf, int len,
1075                                         char *name, unsigned int size)
1076 {
1077         struct domain_hdr *hdr = (void *) buf;
1078         uint16_t qdcount = ntohs(hdr->qdcount);
1079         uint16_t arcount = ntohs(hdr->arcount);
1080         unsigned char *ptr;
1081         char *last_label = NULL;
1082         unsigned int remain, used = 0;
1083
1084         if (len < 12)
1085                 return -EINVAL;
1086
1087         DBG("id 0x%04x qr %d opcode %d qdcount %d arcount %d",
1088                                         hdr->id, hdr->qr, hdr->opcode,
1089                                                         qdcount, arcount);
1090
1091         if (hdr->qr != 0 || qdcount != 1)
1092                 return -EINVAL;
1093
1094         memset(name, 0, size);
1095
1096         ptr = buf + sizeof(struct domain_hdr);
1097         remain = len - sizeof(struct domain_hdr);
1098
1099         while (remain > 0) {
1100                 uint8_t len = *ptr;
1101
1102                 if (len == 0x00) {
1103                         last_label = (char *) (ptr + 1);
1104                         break;
1105                 }
1106
1107                 if (used + len + 1 > size)
1108                         return -ENOBUFS;
1109
1110                 strncat(name, (char *) (ptr + 1), len);
1111                 strcat(name, ".");
1112
1113                 used += len + 1;
1114
1115                 ptr += len + 1;
1116                 remain -= len + 1;
1117         }
1118
1119         if (last_label && arcount && remain >= 9 && last_label[4] == 0 &&
1120                                 !memcmp(last_label + 5, opt_edns0_type, 2)) {
1121                 uint16_t edns0_bufsize;
1122
1123                 edns0_bufsize = last_label[7] << 8 | last_label[8];
1124
1125                 DBG("EDNS0 buffer size %u", edns0_bufsize);
1126
1127                 /* This is an evil hack until full TCP support has been
1128                  * implemented.
1129                  *
1130                  * Somtimes the EDNS0 request gets send with a too-small
1131                  * buffer size. Since glibc doesn't seem to crash when it
1132                  * gets a response biffer then it requested, just bump
1133                  * the buffer size up to 4KiB.
1134                  */
1135                 if (edns0_bufsize < 0x1000) {
1136                         last_label[7] = 0x10;
1137                         last_label[8] = 0x00;
1138                 }
1139         }
1140
1141         DBG("query %s", name);
1142
1143         return 0;
1144 }
1145
1146 static gboolean tcp_listener_event(GIOChannel *channel, GIOCondition condition,
1147                                                         gpointer user_data)
1148 {
1149         unsigned char buf[768];
1150         char query[512];
1151         struct request_data *req;
1152         struct server_data *server;
1153         int sk, client_sk, len, err;
1154         struct sockaddr_in6 client_addr;
1155         socklen_t client_addr_len = sizeof(client_addr);
1156         GSList *list;
1157         struct listener_data *ifdata = user_data;
1158
1159         DBG("condition 0x%x", condition);
1160
1161         if (condition & (G_IO_NVAL | G_IO_ERR | G_IO_HUP)) {
1162                 if (ifdata->tcp_listener_watch > 0)
1163                         g_source_remove(ifdata->tcp_listener_watch);
1164                 ifdata->tcp_listener_watch = 0;
1165
1166                 connman_error("Error with TCP listener channel");
1167
1168                 return FALSE;
1169         }
1170
1171         sk = g_io_channel_unix_get_fd(channel);
1172
1173         client_sk = accept(sk, (void *)&client_addr, &client_addr_len);
1174         if (client_sk < 0) {
1175                 connman_error("Accept failure on TCP listener");
1176                 ifdata->tcp_listener_watch = 0;
1177                 return FALSE;
1178         }
1179
1180         len = recv(client_sk, buf, sizeof(buf), 0);
1181         if (len < 2)
1182                 return TRUE;
1183
1184         DBG("Received %d bytes (id 0x%04x)", len, buf[2] | buf[3] << 8);
1185
1186         err = parse_request(buf + 2, len - 2, query, sizeof(query));
1187         if (err < 0 || (g_slist_length(server_list) == 0)) {
1188                 send_response(client_sk, buf, len, NULL, 0, IPPROTO_TCP);
1189                 return TRUE;
1190         }
1191
1192         req = g_try_new0(struct request_data, 1);
1193         if (req == NULL)
1194                 return TRUE;
1195
1196         memcpy(&req->sa, &client_addr, client_addr_len);
1197         req->sa_len = client_addr_len;
1198         req->client_sk = client_sk;
1199         req->protocol = IPPROTO_TCP;
1200
1201         request_id += 2;
1202         if (request_id == 0x0000 || request_id == 0xffff)
1203                 request_id += 2;
1204
1205         req->srcid = buf[2] | (buf[3] << 8);
1206         req->dstid = request_id;
1207         req->altid = request_id + 1;
1208         req->request_len = len;
1209
1210         buf[2] = req->dstid & 0xff;
1211         buf[3] = req->dstid >> 8;
1212
1213         req->numserv = 0;
1214         req->ifdata = (struct listener_data *) ifdata;
1215         req->append_domain = FALSE;
1216         request_list = g_slist_append(request_list, req);
1217
1218         for (list = server_list; list; list = list->next) {
1219                 struct server_data *data = list->data;
1220                 GList *domains;
1221
1222                 if (data->protocol != IPPROTO_UDP || data->enabled == FALSE)
1223                         continue;
1224
1225                 server = create_server(data->interface, NULL,
1226                                         data->server, IPPROTO_TCP);
1227
1228                 /*
1229                  * If server is NULL, we're not connected yet.
1230                  * Copy the relevant buffers and continue with
1231                  * the next nameserver.
1232                  * The request will actually be sent once we're
1233                  * properly connected over TCP to this nameserver.
1234                  */
1235                 if (server == NULL) {
1236                         req->request = g_try_malloc0(req->request_len);
1237                         if (req->request == NULL)
1238                                 return TRUE;
1239
1240                         memcpy(req->request, buf, req->request_len);
1241
1242                         req->name = g_try_malloc0(sizeof(query));
1243                         if (req->name == NULL) {
1244                                 g_free(req->request);
1245                                 return TRUE;
1246                         }
1247                         memcpy(req->name, query, sizeof(query));
1248
1249                         continue;
1250                 }
1251
1252                 if (req->timeout > 0)
1253                         g_source_remove(req->timeout);
1254
1255                 for (domains = data->domains; domains;
1256                                 domains = domains->next) {
1257                         char *dom = domains->data;
1258
1259                         DBG("Adding domain %s to %s", dom, server->server);
1260
1261                         server->domains = g_list_append(server->domains,
1262                                                 g_strdup(dom));
1263                 }
1264
1265                 req->timeout = g_timeout_add_seconds(30, request_timeout, req);
1266                 ns_resolv(server, req, buf, query);
1267         }
1268
1269         return TRUE;
1270 }
1271
1272 static gboolean udp_listener_event(GIOChannel *channel, GIOCondition condition,
1273                                                         gpointer user_data)
1274 {
1275         unsigned char buf[768];
1276         char query[512];
1277         struct request_data *req;
1278         struct sockaddr_in6 client_addr;
1279         socklen_t client_addr_len = sizeof(client_addr);
1280         int sk, err, len;
1281         struct listener_data *ifdata = user_data;
1282
1283         if (condition & (G_IO_NVAL | G_IO_ERR | G_IO_HUP)) {
1284                 connman_error("Error with UDP listener channel");
1285                 ifdata->udp_listener_watch = 0;
1286                 return FALSE;
1287         }
1288
1289         sk = g_io_channel_unix_get_fd(channel);
1290
1291         memset(&client_addr, 0, client_addr_len);
1292         len = recvfrom(sk, buf, sizeof(buf), 0, (void *)&client_addr,
1293                        &client_addr_len);
1294         if (len < 2)
1295                 return TRUE;
1296
1297         DBG("Received %d bytes (id 0x%04x)", len, buf[0] | buf[1] << 8);
1298
1299         err = parse_request(buf, len, query, sizeof(query));
1300         if (err < 0 || (g_slist_length(server_list) == 0)) {
1301                 send_response(sk, buf, len, (void *)&client_addr,
1302                                 client_addr_len, IPPROTO_UDP);
1303                 return TRUE;
1304         }
1305
1306         req = g_try_new0(struct request_data, 1);
1307         if (req == NULL)
1308                 return TRUE;
1309
1310         memcpy(&req->sa, &client_addr, client_addr_len);
1311         req->sa_len = client_addr_len;
1312         req->client_sk = 0;
1313         req->protocol = IPPROTO_UDP;
1314
1315         request_id += 2;
1316         if (request_id == 0x0000 || request_id == 0xffff)
1317                 request_id += 2;
1318
1319         req->srcid = buf[0] | (buf[1] << 8);
1320         req->dstid = request_id;
1321         req->altid = request_id + 1;
1322         req->request_len = len;
1323
1324         buf[0] = req->dstid & 0xff;
1325         buf[1] = req->dstid >> 8;
1326
1327         req->numserv = 0;
1328         req->ifdata = (struct listener_data *) ifdata;
1329         req->timeout = g_timeout_add_seconds(5, request_timeout, req);
1330         req->append_domain = FALSE;
1331         request_list = g_slist_append(request_list, req);
1332
1333         return resolv(req, buf, query);
1334 }
1335
1336 static int create_dns_listener(int protocol, struct listener_data *ifdata)
1337 {
1338         GIOChannel *channel;
1339         const char *proto;
1340         union {
1341                 struct sockaddr sa;
1342                 struct sockaddr_in6 sin6;
1343                 struct sockaddr_in sin;
1344         } s;
1345         socklen_t slen;
1346         int sk, type, v6only = 0;
1347         int family = AF_INET6;
1348
1349
1350         DBG("interface %s", ifdata->ifname);
1351
1352         switch (protocol) {
1353         case IPPROTO_UDP:
1354                 proto = "UDP";
1355                 type = SOCK_DGRAM | SOCK_CLOEXEC;
1356                 break;
1357
1358         case IPPROTO_TCP:
1359                 proto = "TCP";
1360                 type = SOCK_STREAM | SOCK_CLOEXEC;
1361                 break;
1362
1363         default:
1364                 return -EINVAL;
1365         }
1366
1367         sk = socket(family, type, protocol);
1368         if (sk < 0 && family == AF_INET6 && errno == EAFNOSUPPORT) {
1369                 connman_error("No IPv6 support; DNS proxy listening only on Legacy IP");
1370                 family = AF_INET;
1371                 sk = socket(family, type, protocol);
1372         }
1373         if (sk < 0) {
1374                 connman_error("Failed to create %s listener socket", proto);
1375                 return -EIO;
1376         }
1377
1378         if (setsockopt(sk, SOL_SOCKET, SO_BINDTODEVICE,
1379                                         ifdata->ifname,
1380                                         strlen(ifdata->ifname) + 1) < 0) {
1381                 connman_error("Failed to bind %s listener interface", proto);
1382                 close(sk);
1383                 return -EIO;
1384         }
1385         /* Ensure it accepts Legacy IP connections too */
1386         if (family == AF_INET6 &&
1387                         setsockopt(sk, SOL_IPV6, IPV6_V6ONLY,
1388                                         &v6only, sizeof(v6only)) < 0) {
1389                 connman_error("Failed to clear V6ONLY on %s listener socket",
1390                               proto);
1391                 close(sk);
1392                 return -EIO;
1393         }
1394
1395         if (family == AF_INET) {
1396                 memset(&s.sin, 0, sizeof(s.sin));
1397                 s.sin.sin_family = AF_INET;
1398                 s.sin.sin_port = htons(53);
1399                 s.sin.sin_addr.s_addr = htonl(INADDR_ANY);
1400                 slen = sizeof(s.sin);
1401         } else {
1402                 memset(&s.sin6, 0, sizeof(s.sin6));
1403                 s.sin6.sin6_family = AF_INET6;
1404                 s.sin6.sin6_port = htons(53);
1405                 s.sin6.sin6_addr = in6addr_any;
1406                 slen = sizeof(s.sin6);
1407         }
1408
1409         if (bind(sk, &s.sa, slen) < 0) {
1410                 connman_error("Failed to bind %s listener socket", proto);
1411                 close(sk);
1412                 return -EIO;
1413         }
1414
1415         if (protocol == IPPROTO_TCP && listen(sk, 10) < 0) {
1416                 connman_error("Failed to listen on TCP socket");
1417                 close(sk);
1418                 return -EIO;
1419         }
1420
1421         channel = g_io_channel_unix_new(sk);
1422         if (channel == NULL) {
1423                 connman_error("Failed to create %s listener channel", proto);
1424                 close(sk);
1425                 return -EIO;
1426         }
1427
1428         g_io_channel_set_close_on_unref(channel, TRUE);
1429
1430         if (protocol == IPPROTO_TCP) {
1431                 ifdata->tcp_listener_channel = channel;
1432                 ifdata->tcp_listener_watch = g_io_add_watch(channel,
1433                                 G_IO_IN, tcp_listener_event, (gpointer) ifdata);
1434         } else {
1435                 ifdata->udp_listener_channel = channel;
1436                 ifdata->udp_listener_watch = g_io_add_watch(channel,
1437                                 G_IO_IN, udp_listener_event, (gpointer) ifdata);
1438         }
1439
1440         return 0;
1441 }
1442
1443 static void destroy_udp_listener(struct listener_data *ifdata)
1444 {
1445         DBG("interface %s", ifdata->ifname);
1446
1447         if (ifdata->udp_listener_watch > 0)
1448                 g_source_remove(ifdata->udp_listener_watch);
1449
1450         g_io_channel_unref(ifdata->udp_listener_channel);
1451 }
1452
1453 static void destroy_tcp_listener(struct listener_data *ifdata)
1454 {
1455         DBG("interface %s", ifdata->ifname);
1456
1457         if (ifdata->tcp_listener_watch > 0)
1458                 g_source_remove(ifdata->tcp_listener_watch);
1459
1460         g_io_channel_unref(ifdata->tcp_listener_channel);
1461 }
1462
1463 static int create_listener(struct listener_data *ifdata)
1464 {
1465         int err;
1466
1467         err = create_dns_listener(IPPROTO_UDP, ifdata);
1468         if (err < 0)
1469                 return err;
1470
1471         err = create_dns_listener(IPPROTO_TCP, ifdata);
1472         if (err < 0) {
1473                 destroy_udp_listener(ifdata);
1474                 return err;
1475         }
1476
1477         if (g_strcmp0(ifdata->ifname, "lo") == 0)
1478                 __connman_resolvfile_append("lo", NULL, "127.0.0.1");
1479
1480         return 0;
1481 }
1482
1483 static void destroy_listener(struct listener_data *ifdata)
1484 {
1485         GSList *list;
1486
1487         if (g_strcmp0(ifdata->ifname, "lo") == 0)
1488                 __connman_resolvfile_remove("lo", NULL, "127.0.0.1");
1489
1490         for (list = request_pending_list; list; list = list->next) {
1491                 struct request_data *req = list->data;
1492
1493                 DBG("Dropping pending request (id 0x%04x -> 0x%04x)",
1494                                                 req->srcid, req->dstid);
1495
1496                 g_free(req->resp);
1497                 g_free(req->request);
1498                 g_free(req->name);
1499                 g_free(req);
1500                 list->data = NULL;
1501         }
1502
1503         g_slist_free(request_pending_list);
1504         request_pending_list = NULL;
1505
1506         for (list = request_list; list; list = list->next) {
1507                 struct request_data *req = list->data;
1508
1509                 DBG("Dropping request (id 0x%04x -> 0x%04x)",
1510                                                 req->srcid, req->dstid);
1511
1512                 g_free(req->resp);
1513                 g_free(req->request);
1514                 g_free(req->name);
1515                 g_free(req);
1516                 list->data = NULL;
1517         }
1518
1519         g_slist_free(request_list);
1520         request_list = NULL;
1521
1522         destroy_tcp_listener(ifdata);
1523         destroy_udp_listener(ifdata);
1524 }
1525
1526 int __connman_dnsproxy_add_listener(const char *interface)
1527 {
1528         struct listener_data *ifdata;
1529         int err;
1530
1531         DBG("interface %s", interface);
1532
1533         if (g_hash_table_lookup(listener_table, interface) != NULL)
1534                 return 0;
1535
1536         ifdata = g_try_new0(struct listener_data, 1);
1537         if (ifdata == NULL)
1538                 return -ENOMEM;
1539
1540         ifdata->ifname = g_strdup(interface);
1541         ifdata->udp_listener_channel = NULL;
1542         ifdata->udp_listener_watch = 0;
1543         ifdata->tcp_listener_channel = NULL;
1544         ifdata->tcp_listener_watch = 0;
1545
1546         err = create_listener(ifdata);
1547         if (err < 0) {
1548                 connman_error("Couldn't create listener for %s err %d",
1549                                 interface, err);
1550                 g_free(ifdata->ifname);
1551                 g_free(ifdata);
1552                 return err;
1553         }
1554         g_hash_table_insert(listener_table, ifdata->ifname, ifdata);
1555         return 0;
1556 }
1557
1558 void __connman_dnsproxy_remove_listener(const char *interface)
1559 {
1560         struct listener_data *ifdata;
1561
1562         DBG("interface %s", interface);
1563
1564         ifdata = g_hash_table_lookup(listener_table, interface);
1565         if (ifdata == NULL)
1566                 return;
1567
1568         destroy_listener(ifdata);
1569
1570         g_hash_table_remove(listener_table, interface);
1571 }
1572
1573 static void remove_listener(gpointer key, gpointer value, gpointer user_data)
1574 {
1575         __connman_dnsproxy_remove_listener(key);
1576 }
1577
1578 int __connman_dnsproxy_init(void)
1579 {
1580         int err;
1581
1582         DBG("");
1583
1584         listener_table = g_hash_table_new_full(g_str_hash, g_str_equal,
1585                                                         g_free, g_free);
1586         err = __connman_dnsproxy_add_listener("lo");
1587         if (err < 0)
1588                 return err;
1589
1590         err = connman_notifier_register(&dnsproxy_notifier);
1591         if (err < 0)
1592                 goto destroy;
1593
1594         return 0;
1595
1596 destroy:
1597         __connman_dnsproxy_remove_listener("lo");
1598         g_hash_table_destroy(listener_table);
1599
1600         return err;
1601 }
1602
1603 void __connman_dnsproxy_cleanup(void)
1604 {
1605         DBG("");
1606
1607         connman_notifier_unregister(&dnsproxy_notifier);
1608
1609         g_hash_table_foreach(listener_table, remove_listener, NULL);
1610
1611         g_hash_table_destroy(listener_table);
1612 }