plugins/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
  33 #define CONNMAN_API_SUBJECT_TO_CHANGE
  34 #include <connman/plugin.h>
  35 #include <connman/resolver.h>
  36 #include <connman/notifier.h>
  37 #include <connman/ondemand.h>
  38 #include <connman/log.h>
  39
  40 #include <glib.h>
  41
  42 #if __BYTE_ORDER == __LITTLE_ENDIAN
  43 struct domain_hdr {
  44         uint16_t id;
  45         uint8_t rd:1;
  46         uint8_t tc:1;
  47         uint8_t aa:1;
  48         uint8_t opcode:4;
  49         uint8_t qr:1;
  50         uint8_t rcode:4;
  51         uint8_t z:3;
  52         uint8_t ra:1;
  53         uint16_t qdcount;
  54         uint16_t ancount;
  55         uint16_t nscount;
  56         uint16_t arcount;
  57 } __attribute__ ((packed));
  58 #elif __BYTE_ORDER == __BIG_ENDIAN
  59 struct domain_hdr {
  60         uint16_t id;
  61         uint8_t qr:1;
  62         uint8_t opcode:4;
  63         uint8_t aa:1;
  64         uint8_t tc:1;
  65         uint8_t rd:1;
  66         uint8_t ra:1;
  67         uint8_t z:3;
  68         uint8_t rcode:4;
  69         uint16_t qdcount;
  70         uint16_t ancount;
  71         uint16_t nscount;
  72         uint16_t arcount;
  73 } __attribute__ ((packed));
  74 #else
  75 #error "Unknown byte order"
  76 #endif
  77
  78 struct server_data {
  79         char *interface;
  80         char *domain;
  81         char *server;
  82         int protocol;
  83         GIOChannel *channel;
  84         guint watch;
  85         guint timeout;
  86         gboolean enabled;
  87         gboolean connected;
  88 };
  89
  90 struct request_data {
  91         struct sockaddr_in sin;
  92         int client_sk;
  93         int protocol;
  94         socklen_t len;
  95         guint16 srcid;
  96         guint16 dstid;
  97         guint16 altid;
  98         guint timeout;
  99         guint watch;
 100         guint numserv;
 101         guint numresp;
 102         gpointer request;
 103         gsize request_len;
 104         gpointer name;
 105         gpointer resp;
 106         gsize resplen;
 107 };
 108
 109 static GSList *server_list = NULL;
 110 static GSList *request_list = NULL;
 111 static GSList *request_pending_list = NULL;
 112 static guint16 request_id = 0x0000;
 113
 114 static GIOChannel *udp_listener_channel = NULL;
 115 static guint udp_listener_watch = 0;
 116 static GIOChannel *tcp_listener_channel = NULL;
 117 static guint tcp_listener_watch = 0;
 118
 119 static int protocol_offset(int protocol)
 120 {
 121         switch (protocol) {
 122         case IPPROTO_UDP:
 123                 return 0;
 124
 125         case IPPROTO_TCP:
 126                 return 2;
 127
 128         default:
 129                 return -EINVAL;
 130         }
 131
 132 }
 133
 134 static struct request_data *find_request(guint16 id)
 135 {
 136         GSList *list;
 137
 138         for (list = request_list; list; list = list->next) {
 139                 struct request_data *req = list->data;
 140
 141                 if (req->dstid == id || req->altid == id)
 142                         return req;
 143         }
 144
 145         return NULL;
 146 }
 147
 148 static struct server_data *find_server(const char *interface,
 149                                         const char *domain, const char *server,
 150                                                 int protocol)
 151 {
 152         GSList *list;
 153
 154         DBG("interface %s server %s", interface, server);
 155
 156         for (list = server_list; list; list = list->next) {
 157                 struct server_data *data = list->data;
 158
 159                 if (data->interface == NULL || data->server == NULL)
 160                         continue;
 161
 162                 if (g_str_equal(data->interface, interface) == TRUE &&
 163                                 g_str_equal(data->server, server) == TRUE &&
 164                                 data->protocol == protocol) {
 165                         if (domain == NULL) {
 166                                 if (data->domain == NULL)
 167                                         return data;
 168                                 continue;
 169                         }
 170
 171                         if (g_str_equal(data->domain, domain) == TRUE)
 172                                 return data;
 173                 }
 174         }
 175
 176         return NULL;
 177 }
 178
 179
 180 static void send_response(int sk, unsigned char *buf, int len,
 181                                 const struct sockaddr *to, socklen_t tolen,
 182                                 int protocol)
 183 {
 184         struct domain_hdr *hdr;
 185         int err, offset = protocol_offset(protocol);
 186
 187         DBG("");
 188
 189         if (offset < 0)
 190                 return;
 191
 192         if (len < 12)
 193                 return;
 194
 195         hdr = (void*) (buf + offset);
 196
 197         DBG("id 0x%04x qr %d opcode %d", hdr->id, hdr->qr, hdr->opcode);
 198
 199         hdr->qr = 1;
 200         hdr->rcode = 2;
 201
 202         hdr->ancount = 0;
 203         hdr->nscount = 0;
 204         hdr->arcount = 0;
 205
 206         err = sendto(sk, buf, len, 0, to, tolen);
 207 }
 208
 209 static gboolean request_timeout(gpointer user_data)
 210 {
 211         struct request_data *req = user_data;
 212
 213         DBG("id 0x%04x", req->srcid);
 214
 215         if (req == NULL)
 216                 return FALSE;
 217
 218         request_list = g_slist_remove(request_list, req);
 219         req->numserv--;
 220
 221         if (req->resplen > 0 && req->resp != NULL) {
 222                 int sk, err;
 223
 224                 sk = g_io_channel_unix_get_fd(udp_listener_channel);
 225
 226                 err = sendto(sk, req->resp, req->resplen, 0,
 227                                 (struct sockaddr *) &req->sin, req->len);
 228         } else if (req->request && req->numserv == 0) {
 229                 struct domain_hdr *hdr;
 230
 231                 if (req->protocol == IPPROTO_TCP) {
 232                         hdr = (void *) (req->request + 2);
 233                         hdr->id = req->srcid;
 234                         send_response(req->client_sk, req->request,
 235                                         req->request_len, NULL, 0, IPPROTO_TCP);
 236
 237                 } else if (req->protocol == IPPROTO_UDP) {
 238                         int sk;
 239
 240                         hdr = (void *) (req->request);
 241                         hdr->id = req->srcid;
 242                         sk = g_io_channel_unix_get_fd(udp_listener_channel);
 243                         send_response(sk, req->request, req->request_len,
 244                                         (struct sockaddr *)&req->sin,
 245                                                 sizeof(req->sin), IPPROTO_UDP);
 246                 }
 247         }
 248
 249         g_free(req->resp);
 250         g_free(req);
 251
 252         return FALSE;
 253 }
 254
 255 static int append_query(unsigned char *buf, unsigned int size,
 256                                 const char *query, const char *domain)
 257 {
 258         unsigned char *ptr = buf;
 259         char *offset;
 260
 261         DBG("query %s domain %s", query, domain);
 262
 263         offset = (char *) query;
 264         while (offset != NULL) {
 265                 char *tmp;
 266
 267                 tmp = strchr(offset, '.');
 268                 if (tmp == NULL) {
 269                         if (strlen(offset) == 0)
 270                                 break;
 271                         *ptr = strlen(offset);
 272                         memcpy(ptr + 1, offset, strlen(offset));
 273                         ptr += strlen(offset) + 1;
 274                         break;
 275                 }
 276
 277                 *ptr = tmp - offset;
 278                 memcpy(ptr + 1, offset, tmp - offset);
 279                 ptr += tmp - offset + 1;
 280
 281                 offset = tmp + 1;
 282         }
 283
 284         offset = (char *) domain;
 285         while (offset != NULL) {
 286                 char *tmp;
 287
 288                 tmp = strchr(offset, '.');
 289                 if (tmp == NULL) {
 290                         if (strlen(offset) == 0)
 291                                 break;
 292                         *ptr = strlen(offset);
 293                         memcpy(ptr + 1, offset, strlen(offset));
 294                         ptr += strlen(offset) + 1;
 295                         break;
 296                 }
 297
 298                 *ptr = tmp - offset;
 299                 memcpy(ptr + 1, offset, tmp - offset);
 300                 ptr += tmp - offset + 1;
 301
 302                 offset = tmp + 1;
 303         }
 304
 305         *ptr++ = 0x00;
 306
 307         return ptr - buf;
 308 }
 309
 310 static int ns_resolv(struct server_data *server, struct request_data *req,
 311                                 gpointer request, gpointer name)
 312 {
 313         int sk, err;
 314
 315         sk = g_io_channel_unix_get_fd(server->channel);
 316
 317         err = send(sk, request, req->request_len, 0);
 318
 319         req->numserv++;
 320
 321         if (server->domain != NULL && server->protocol == IPPROTO_UDP) {
 322                 unsigned char alt[1024];
 323                 struct domain_hdr *hdr = (void *) &alt;
 324                 int altlen, domlen;
 325
 326                 domlen = strlen(server->domain) + 1;
 327                 if (domlen < 5)
 328                         return -EINVAL;
 329
 330                 alt[0] = req->altid & 0xff;
 331                 alt[1] = req->altid >> 8;
 332
 333                 memcpy(alt + 2, request + 2, 10);
 334                 hdr->qdcount = htons(1);
 335
 336                 altlen = append_query(alt + 12, sizeof(alt) - 12,
 337                                         name, server->domain);
 338                 if (altlen < 0)
 339                         return -EINVAL;
 340
 341                 altlen += 12;
 342
 343                 memcpy(alt + altlen, request + altlen - domlen,
 344                                 req->request_len - altlen + domlen);
 345
 346                 err = send(sk, alt, req->request_len + domlen + 1, 0);
 347
 348                 req->numserv++;
 349         }
 350
 351         return 0;
 352 }
 353
 354 static int forward_dns_reply(unsigned char *reply, int reply_len, int protocol)
 355 {
 356         struct domain_hdr *hdr;
 357         struct request_data *req;
 358         int dns_id, sk, err, offset = protocol_offset(protocol);
 359
 360         if (offset < 0)
 361                 return offset;
 362
 363         hdr = (void *)(reply + offset);
 364         dns_id = reply[offset] | reply[offset + 1] << 8;
 365
 366         DBG("Received %d bytes (id 0x%04x)", reply_len, dns_id);
 367
 368         req = find_request(dns_id);
 369         if (req == NULL)
 370                 return -EINVAL;
 371
 372         DBG("id 0x%04x rcode %d", hdr->id, hdr->rcode);
 373
 374         reply[offset] = req->srcid & 0xff;
 375         reply[offset + 1] = req->srcid >> 8;
 376
 377         req->numresp++;
 378
 379         if (hdr->rcode == 0 || req->resp == NULL) {
 380                 g_free(req->resp);
 381                 req->resplen = 0;
 382
 383                 req->resp = g_try_malloc(reply_len);
 384                 if (req->resp == NULL)
 385                         return -ENOMEM;
 386
 387                 memcpy(req->resp, reply, reply_len);
 388                 req->resplen = reply_len;
 389         }
 390
 391         if (hdr->rcode > 0 && req->numresp < req->numserv)
 392                 return -EINVAL;
 393
 394         if (req->timeout > 0)
 395                 g_source_remove(req->timeout);
 396
 397         request_list = g_slist_remove(request_list, req);
 398
 399         if (protocol == IPPROTO_UDP) {
 400                 sk = g_io_channel_unix_get_fd(udp_listener_channel);
 401                 err = sendto(sk, req->resp, req->resplen, 0,
 402                                 (struct sockaddr *) &req->sin, req->len);
 403         } else {
 404                 sk = req->client_sk;
 405                 err = send(sk, req->resp, req->resplen, 0);
 406                 close(sk);
 407         }
 408
 409         g_free(req->resp);
 410         g_free(req);
 411
 412         return err;
 413 }
 414
 415 static void destroy_server(struct server_data *server)
 416 {
 417         DBG("interface %s server %s", server->interface, server->server);
 418
 419         server_list = g_slist_remove(server_list, server);
 420
 421         if (server->watch > 0)
 422                 g_source_remove(server->watch);
 423
 424         if (server->timeout > 0)
 425                 g_source_remove(server->timeout);
 426
 427         g_io_channel_unref(server->channel);
 428
 429         if (server->protocol == IPPROTO_UDP)
 430                 connman_info("Removing DNS server %s", server->server);
 431
 432         g_free(server->server);
 433         g_free(server->domain);
 434         g_free(server->interface);
 435         g_free(server);
 436 }
 437
 438 static gboolean udp_server_event(GIOChannel *channel, GIOCondition condition,
 439                                                         gpointer user_data)
 440 {
 441         struct server_data *data = user_data;
 442         unsigned char buf[4096];
 443         int sk, err, len;
 444
 445         if (condition & (G_IO_NVAL | G_IO_ERR | G_IO_HUP)) {
 446                 connman_error("Error with server channel");
 447                 data->watch = 0;
 448                 return FALSE;
 449         }
 450
 451         sk = g_io_channel_unix_get_fd(channel);
 452
 453         len = recv(sk, buf, sizeof(buf), 0);
 454         if (len < 12)
 455                 return TRUE;
 456
 457         err = forward_dns_reply(buf, len, IPPROTO_UDP);
 458
 459         return TRUE;
 460 }
 461
 462 static gboolean tcp_server_event(GIOChannel *channel, GIOCondition condition,
 463                                                         gpointer user_data)
 464 {
 465         int sk;
 466         struct server_data *server = user_data;
 467
 468         sk = g_io_channel_unix_get_fd(channel);
 469         if (sk == 0)
 470                 return FALSE;
 471
 472         if (condition & (G_IO_NVAL | G_IO_ERR | G_IO_HUP)) {
 473                 GSList *list;
 474
 475                 DBG("TCP server channel closed");
 476
 477                 for (list = request_list; list; list = list->next) {
 478                         struct request_data *req = list->data;
 479                         struct domain_hdr *hdr;
 480
 481                         if (req->protocol == IPPROTO_UDP)
 482                                 continue;
 483
 484                         if (req->request == NULL)
 485                                 continue;
 486
 487                         /*
 488                          * If we're not waiting for any further response
 489                          * from another name server, then we send an error
 490                          * response to the client.
 491                          */
 492                         if (req->numserv && --(req->numserv))
 493                                 continue;
 494
 495                         hdr = (void *) (req->request + 2);
 496                         hdr->id = req->srcid;
 497                         send_response(req->client_sk, req->request,
 498                                         req->request_len, NULL, 0, IPPROTO_TCP);
 499
 500                         request_list = g_slist_remove(request_list, req);
 501                 }
 502
 503                 destroy_server(server);
 504
 505                 return FALSE;
 506         }
 507
 508         if ((condition & G_IO_OUT) && !server->connected) {
 509                 GSList *list;
 510
 511                 server->connected = TRUE;
 512                 server_list = g_slist_append(server_list, server);
 513
 514                 if (server->timeout > 0) {
 515                         g_source_remove(server->timeout);
 516                         server->timeout = 0;
 517                 }
 518
 519                 for (list = request_list; list; list = list->next) {
 520                         struct request_data *req = list->data;
 521
 522                         if (req->protocol == IPPROTO_UDP)
 523                                 continue;
 524
 525                         DBG("Sending req %s over TCP", (char *)req->name);
 526
 527                         if (req->timeout > 0)
 528                                 g_source_remove(req->timeout);
 529
 530                         req->timeout = g_timeout_add_seconds(30,
 531                                                 request_timeout, req);
 532                         ns_resolv(server, req, req->request, req->name);
 533                 }
 534
 535         } else if (condition & G_IO_IN) {
 536                 int len, bytes_recv, total_bytes_recv;
 537                 unsigned char reply_len_buf[2];
 538                 uint16_t reply_len;
 539                 unsigned char *reply;
 540
 541                 len = recv(sk, reply_len_buf, 2, 0);
 542                 if (len < 2)
 543                         return TRUE;
 544
 545                 reply_len = reply_len_buf[1] | reply_len_buf[0] << 8;
 546
 547                 DBG("TCP reply %d bytes", reply_len);
 548
 549                 reply = g_try_malloc(reply_len + 2);
 550                 if (reply == NULL)
 551                         return TRUE;
 552
 553                 reply[0] = reply_len_buf[0];
 554                 reply[1] = reply_len_buf[1];
 555
 556                 total_bytes_recv = bytes_recv = 0;
 557                 while (total_bytes_recv < reply_len) {
 558                         bytes_recv = recv(sk, reply + 2, reply_len, 0);
 559                         if (bytes_recv < 0)
 560                                 break;
 561
 562                         total_bytes_recv += bytes_recv;
 563                 }
 564
 565                 forward_dns_reply(reply, reply_len + 2, IPPROTO_TCP);
 566
 567                 g_free(reply);
 568
 569                 destroy_server(server);
 570
 571                 return FALSE;
 572         }
 573
 574         return TRUE;
 575 }
 576
 577 static gboolean tcp_idle_timeout(gpointer user_data)
 578 {
 579         struct server_data *server = user_data;
 580
 581         DBG("");
 582
 583         if (server == NULL)
 584                 return FALSE;
 585
 586         destroy_server(server);
 587
 588         return FALSE;
 589 }
 590
 591 static struct server_data *create_server(const char *interface,
 592                                         const char *domain, const char *server,
 593                                         int protocol)
 594 {
 595         struct server_data *data;
 596         struct sockaddr_in sin;
 597         int sk, type, ret;
 598
 599         DBG("interface %s server %s", interface, server);
 600
 601         switch (protocol) {
 602         case IPPROTO_UDP:
 603                 type = SOCK_DGRAM;
 604                 break;
 605
 606         case IPPROTO_TCP:
 607                 type = SOCK_STREAM;
 608                 break;
 609
 610         default:
 611                 return NULL;
 612         }
 613
 614         data = find_server(interface, domain, server, protocol);
 615         if (data) {
 616                 if (data->watch > 0)
 617                         g_source_remove(data->watch);
 618                 data->watch = g_io_add_watch(data->channel,
 619                         G_IO_OUT | G_IO_IN | G_IO_HUP | G_IO_NVAL | G_IO_ERR,
 620                                                 tcp_server_event, data);
 621                 return data;
 622         }
 623
 624         sk = socket(AF_INET, type, protocol);
 625         if (sk < 0) {
 626                 connman_error("Failed to create server %s socket", server);
 627                 return NULL;
 628         }
 629
 630         if (interface != NULL) {
 631                 if (setsockopt(sk, SOL_SOCKET, SO_BINDTODEVICE,
 632                                 interface, strlen(interface) + 1) < 0) {
 633                         connman_error("Failed to bind server %s "
 634                                                 "to interface %s",
 635                                                         server, interface);
 636                         close(sk);
 637                         return NULL;
 638                 }
 639         }
 640
 641         data = g_try_new0(struct server_data, 1);
 642         if (data == NULL) {
 643                 connman_error("Failed to allocate server %s data", server);
 644                 close(sk);
 645                 return NULL;
 646         }
 647
 648         data->channel = g_io_channel_unix_new(sk);
 649         if (data->channel == NULL) {
 650                 connman_error("Failed to create server %s channel", server);
 651                 close(sk);
 652                 g_free(data);
 653                 return NULL;
 654         }
 655
 656         g_io_channel_set_close_on_unref(data->channel, TRUE);
 657
 658         if (protocol == IPPROTO_TCP) {
 659                 g_io_channel_set_flags(data->channel, G_IO_FLAG_NONBLOCK, NULL);
 660                 data->watch = g_io_add_watch(data->channel,
 661                         G_IO_OUT | G_IO_IN | G_IO_HUP | G_IO_NVAL | G_IO_ERR,
 662                                                 tcp_server_event, data);
 663                 data->timeout = g_timeout_add_seconds(30, tcp_idle_timeout,
 664                                                                 data);
 665         } else
 666                 data->watch = g_io_add_watch(data->channel, G_IO_IN,
 667                                                 udp_server_event, data);
 668
 669         data->interface = g_strdup(interface);
 670         data->domain = g_strdup(domain);
 671         data->server = g_strdup(server);
 672         data->protocol = protocol;
 673
 674         memset(&sin, 0, sizeof(sin));
 675         sin.sin_family = AF_INET;
 676         sin.sin_port = htons(53);
 677         sin.sin_addr.s_addr = inet_addr(server);
 678
 679         ret = connect(sk, (struct sockaddr *) &sin, sizeof(sin));
 680         if (ret < 0) {
 681                 if ((protocol == IPPROTO_TCP && errno != EINPROGRESS) ||
 682                                 protocol == IPPROTO_UDP) {
 683                         connman_error("Failed to connect to server %s", server);
 684                         close(sk);
 685                         g_free(data);
 686                         return NULL;
 687                 }
 688         }
 689
 690         if (protocol == IPPROTO_UDP) {
 691                 /* Enable new servers by default */
 692                 data->enabled = TRUE;
 693                 connman_info("Adding DNS server %s", data->server);
 694
 695                 server_list = g_slist_append(server_list, data);
 696
 697                 return data;
 698         }
 699
 700         return NULL;
 701 }
 702
 703 static gboolean resolv(struct request_data *req,
 704                                 gpointer request, gpointer name)
 705 {
 706         GSList *list;
 707
 708         for (list = server_list; list; list = list->next) {
 709                 struct server_data *data = list->data;
 710
 711                 DBG("server %s domain %s enabled %d",
 712                                 data->server, data->domain, data->enabled);
 713
 714                 if (data->enabled == FALSE)
 715                         continue;
 716
 717                 if (ns_resolv(data, req, request, name) < 0)
 718                         continue;
 719         }
 720
 721         return TRUE;
 722 }
 723
 724 static int dnsproxy_append(const char *interface, const char *domain,
 725                                                         const char *server)
 726 {
 727         struct server_data *data;
 728
 729         DBG("interface %s server %s", interface, server);
 730
 731         if (g_str_equal(server, "127.0.0.1") == TRUE)
 732                 return -ENODEV;
 733
 734         data = create_server(interface, domain, server, IPPROTO_UDP);
 735         if (data == NULL)
 736                 return -EIO;
 737
 738         return 0;
 739 }
 740
 741 static void remove_server(const char *interface, const char *domain,
 742                         const char *server, int protocol)
 743 {
 744         struct server_data *data;
 745
 746         data = find_server(interface, domain, server, protocol);
 747         if (data == NULL)
 748                 return;
 749
 750         destroy_server(data);
 751 }
 752
 753 static int dnsproxy_remove(const char *interface, const char *domain,
 754                                                         const char *server)
 755 {
 756         DBG("interface %s server %s", interface, server);
 757
 758         if (g_str_equal(server, "127.0.0.1") == TRUE)
 759                 return -ENODEV;
 760
 761         remove_server(interface, domain, server, IPPROTO_UDP);
 762         remove_server(interface, domain, server, IPPROTO_TCP);
 763
 764         return 0;
 765 }
 766
 767 static void dnsproxy_flush(void)
 768 {
 769         GSList *list;
 770
 771         list = request_pending_list;
 772         while (list) {
 773                 struct request_data *req = list->data;
 774
 775                 list = list->next;
 776
 777                 request_pending_list =
 778                                 g_slist_remove(request_pending_list, req);
 779                 resolv(req, req->request, req->name);
 780                 g_free(req->request);
 781                 g_free(req->name);
 782         }
 783 }
 784
 785 static struct connman_resolver dnsproxy_resolver = {
 786         .name           = "dnsproxy",
 787         .priority       = CONNMAN_RESOLVER_PRIORITY_HIGH,
 788         .append         = dnsproxy_append,
 789         .remove         = dnsproxy_remove,
 790         .flush          = dnsproxy_flush,
 791 };
 792
 793 static void dnsproxy_offline_mode(connman_bool_t enabled)
 794 {
 795         GSList *list;
 796
 797         DBG("enabled %d", enabled);
 798
 799         for (list = server_list; list; list = list->next) {
 800                 struct server_data *data = list->data;
 801
 802                 if (enabled == FALSE) {
 803                         connman_info("Enabling DNS server %s", data->server);
 804                         data->enabled = TRUE;
 805                 } else {
 806                         connman_info("Disabling DNS server %s", data->server);
 807                         data->enabled = FALSE;
 808                 }
 809         }
 810 }
 811
 812 static void dnsproxy_default_changed(struct connman_service *service)
 813 {
 814         GSList *list;
 815         char *interface;
 816
 817         DBG("service %p", service);
 818
 819         if (service == NULL) {
 820                 /* When no services are active, then disable DNS proxying */
 821                 dnsproxy_offline_mode(TRUE);
 822                 return;
 823         }
 824
 825         interface = connman_service_get_interface(service);
 826         if (interface == NULL)
 827                 return;
 828
 829         for (list = server_list; list; list = list->next) {
 830                 struct server_data *data = list->data;
 831
 832                 if (g_strcmp0(data->interface, interface) == 0) {
 833                         connman_info("Enabling DNS server %s", data->server);
 834                         data->enabled = TRUE;
 835                 } else {
 836                         connman_info("Disabling DNS server %s", data->server);
 837                         data->enabled = FALSE;
 838                 }
 839         }
 840
 841         g_free(interface);
 842 }
 843
 844 static struct connman_notifier dnsproxy_notifier = {
 845         .name                   = "dnsproxy",
 846         .default_changed        = dnsproxy_default_changed,
 847         .offline_mode           = dnsproxy_offline_mode,
 848 };
 849
 850 static unsigned char opt_edns0_type[2] = { 0x00, 0x29 };
 851
 852 static int parse_request(unsigned char *buf, int len,
 853                                         char *name, unsigned int size)
 854 {
 855         struct domain_hdr *hdr = (void *) buf;
 856         uint16_t qdcount = ntohs(hdr->qdcount);
 857         uint16_t arcount = ntohs(hdr->arcount);
 858         unsigned char *ptr;
 859         char *last_label = NULL;
 860         unsigned int remain, used = 0;
 861
 862         if (len < 12)
 863                 return -EINVAL;
 864
 865         DBG("id 0x%04x qr %d opcode %d qdcount %d arcount %d",
 866                                         hdr->id, hdr->qr, hdr->opcode,
 867                                                         qdcount, arcount);
 868
 869         if (hdr->qr != 0 || qdcount != 1)
 870                 return -EINVAL;
 871
 872         memset(name, 0, size);
 873
 874         ptr = buf + sizeof(struct domain_hdr);
 875         remain = len - sizeof(struct domain_hdr);
 876
 877         while (remain > 0) {
 878                 uint8_t len = *ptr;
 879
 880                 if (len == 0x00) {
 881                         last_label = (char *) (ptr + 1);
 882                         break;
 883                 }
 884
 885                 if (used + len + 1 > size)
 886                         return -ENOBUFS;
 887
 888                 strncat(name, (char *) (ptr + 1), len);
 889                 strcat(name, ".");
 890
 891                 used += len + 1;
 892
 893                 ptr += len + 1;
 894                 remain -= len + 1;
 895         }
 896
 897         if (last_label && arcount && remain >= 9 && last_label[4] == 0 &&
 898                                 !memcmp(last_label + 5, opt_edns0_type, 2)) {
 899                 uint16_t edns0_bufsize;
 900
 901                 edns0_bufsize = last_label[7] << 8 | last_label[8];
 902
 903                 DBG("EDNS0 buffer size %u", edns0_bufsize);
 904
 905                 /* This is an evil hack until full TCP support has been
 906                  * implemented.
 907                  *
 908                  * Somtimes the EDNS0 request gets send with a too-small
 909                  * buffer size. Since glibc doesn't seem to crash when it
 910                  * gets a response biffer then it requested, just bump
 911                  * the buffer size up to 4KiB.
 912                  */
 913                 if (edns0_bufsize < 0x1000) {
 914                         last_label[7] = 0x10;
 915                         last_label[8] = 0x00;
 916                 }
 917         }
 918
 919         DBG("query %s", name);
 920
 921         return 0;
 922 }
 923
 924 static gboolean tcp_listener_event(GIOChannel *channel, GIOCondition condition,
 925                                                         gpointer user_data)
 926 {
 927         unsigned char buf[768];
 928         char query[512];
 929         struct request_data *req;
 930         struct server_data *server;
 931         int sk, client_sk, len, err;
 932         struct sockaddr client_addr;
 933         socklen_t client_addr_len;
 934         GSList *list;
 935
 936         DBG("condition 0x%x", condition);
 937
 938         if (condition & (G_IO_NVAL | G_IO_ERR | G_IO_HUP)) {
 939                 if (tcp_listener_watch > 0)
 940                         g_source_remove(tcp_listener_watch);
 941                 tcp_listener_watch = 0;
 942
 943                 connman_error("Error with TCP listener channel");
 944
 945                 return FALSE;
 946         }
 947
 948         sk = g_io_channel_unix_get_fd(channel);
 949
 950         client_addr_len = sizeof(struct sockaddr);
 951         client_sk = accept(sk, &client_addr, &client_addr_len);
 952         if (client_sk < 0) {
 953                 connman_error("Accept failure on TCP listener");
 954                 tcp_listener_watch = 0;
 955                 return FALSE;
 956         }
 957
 958         len = recv(client_sk, buf, sizeof(buf), 0);
 959         if (len < 2)
 960                 return TRUE;
 961
 962         DBG("Received %d bytes (id 0x%04x)", len, buf[2] | buf[3] << 8);
 963
 964         err = parse_request(buf + 2, len - 2, query, sizeof(query));
 965         if (err < 0 || (g_slist_length(server_list) == 0 &&
 966                                 connman_ondemand_connected())) {
 967                 send_response(client_sk, buf, len, NULL, 0, IPPROTO_TCP);
 968                 return TRUE;
 969         }
 970
 971         req = g_try_new0(struct request_data, 1);
 972         if (req == NULL)
 973                 return TRUE;
 974
 975         memcpy(&req->sin, (struct sockaddr_in *)&client_addr, sizeof(req->sin));
 976         req->client_sk = client_sk;
 977         req->protocol = IPPROTO_TCP;
 978         req->len = client_addr_len;
 979
 980         request_id += 2;
 981         if (request_id == 0x0000 || request_id == 0xffff)
 982                 request_id += 2;
 983
 984         req->srcid = buf[2] | (buf[3] << 8);
 985         req->dstid = request_id;
 986         req->altid = request_id + 1;
 987         req->request_len = len;
 988
 989         buf[2] = req->dstid & 0xff;
 990         buf[3] = req->dstid >> 8;
 991
 992         req->numserv = 0;
 993         request_list = g_slist_append(request_list, req);
 994
 995         for (list = server_list; list; list = list->next) {
 996                 struct server_data *data = list->data;
 997
 998                 if (data->protocol != IPPROTO_UDP || data->enabled == FALSE)
 999                         continue;
1000
1001                 server = create_server(data->interface, data->domain,
1002                                         data->server, IPPROTO_TCP);
1003
1004                 /*
1005                  * If server is NULL, we're not connected yet.
1006                  * Copy the relevant buffers and continue with
1007                  * the next nameserver.
1008                  * The request will actually be sent once we're
1009                  * properly connected over TCP to this nameserver.
1010                  */
1011                 if (server == NULL) {
1012                         req->request = g_try_malloc0(req->request_len);
1013                         if (req->request == NULL)
1014                                 return TRUE;
1015
1016                         memcpy(req->request, buf, req->request_len);
1017
1018                         req->name = g_try_malloc0(sizeof(query));
1019                         if (req->name == NULL) {
1020                                 g_free(req->request);
1021                                 return TRUE;
1022                         }
1023                         memcpy(req->name, query, sizeof(query));
1024
1025                         continue;
1026                 }
1027
1028                 if (req->timeout > 0)
1029                         g_source_remove(req->timeout);
1030
1031                 req->timeout = g_timeout_add_seconds(30, request_timeout, req);
1032                 ns_resolv(server, req, buf, query);
1033         }
1034
1035         return TRUE;
1036 }
1037
1038 static gboolean udp_listener_event(GIOChannel *channel, GIOCondition condition,
1039                                                         gpointer user_data)
1040 {
1041         unsigned char buf[768];
1042         char query[512];
1043         struct request_data *req;
1044         struct sockaddr_in sin;
1045         socklen_t size = sizeof(sin);
1046         int sk, err, len;
1047
1048         if (condition & (G_IO_NVAL | G_IO_ERR | G_IO_HUP)) {
1049                 connman_error("Error with UDP listener channel");
1050                 udp_listener_watch = 0;
1051                 return FALSE;
1052         }
1053
1054         sk = g_io_channel_unix_get_fd(channel);
1055
1056         memset(&sin, 0, sizeof(sin));
1057         len = recvfrom(sk, buf, sizeof(buf), 0,
1058                                         (struct sockaddr *) &sin, &size);
1059         if (len < 2)
1060                 return TRUE;
1061
1062         DBG("Received %d bytes (id 0x%04x)", len, buf[0] | buf[1] << 8);
1063
1064         err = parse_request(buf, len, query, sizeof(query));
1065         if (err < 0 || (g_slist_length(server_list) == 0 &&
1066                                 connman_ondemand_connected())) {
1067                 send_response(sk, buf, len, (struct sockaddr *) &sin, size,
1068                                 IPPROTO_UDP);
1069                 return TRUE;
1070         }
1071
1072         req = g_try_new0(struct request_data, 1);
1073         if (req == NULL)
1074                 return TRUE;
1075
1076         memcpy(&req->sin, &sin, sizeof(sin));
1077         req->client_sk = 0;
1078         req->protocol = IPPROTO_UDP;
1079         req->len = size;
1080
1081         request_id += 2;
1082         if (request_id == 0x0000 || request_id == 0xffff)
1083                 request_id += 2;
1084
1085         req->srcid = buf[0] | (buf[1] << 8);
1086         req->dstid = request_id;
1087         req->altid = request_id + 1;
1088         req->request_len = len;
1089
1090         buf[0] = req->dstid & 0xff;
1091         buf[1] = req->dstid >> 8;
1092
1093         if (!connman_ondemand_connected()) {
1094                 DBG("Starting on demand connection");
1095                 /*
1096                  * We're not connected, let's queue the request and start
1097                  * an on-demand connection.
1098                  */
1099                 req->request = g_try_malloc0(req->request_len);
1100                 if (req->request == NULL)
1101                         return TRUE;
1102
1103                 memcpy(req->request, buf, req->request_len);
1104
1105                 req->name = g_try_malloc0(sizeof(query));
1106                 if (req->name == NULL) {
1107                         g_free(req->request);
1108                         return TRUE;
1109                 }
1110                 memcpy(req->name, query, sizeof(query));
1111
1112                 request_pending_list = g_slist_append(request_pending_list,
1113                                                                         req);
1114
1115                 connman_ondemand_start("", 300);
1116
1117                 return TRUE;
1118         }
1119
1120
1121         req->numserv = 0;
1122         req->timeout = g_timeout_add_seconds(5, request_timeout, req);
1123         request_list = g_slist_append(request_list, req);
1124
1125         return resolv(req, buf, query);
1126 }
1127
1128 static int create_dns_listener(int protocol)
1129 {
1130         GIOChannel *channel;
1131         const char *ifname = "lo", *proto;
1132         struct sockaddr_in sin;
1133         int sk, type;
1134
1135         DBG("");
1136
1137         switch (protocol) {
1138         case IPPROTO_UDP:
1139                 proto = "UDP";
1140                 type = SOCK_DGRAM;
1141                 break;
1142
1143         case IPPROTO_TCP:
1144                 proto = "TCP";
1145                 type = SOCK_STREAM;
1146                 break;
1147
1148         default:
1149                 return -EINVAL;
1150         }
1151
1152         sk = socket(AF_INET, type, protocol);
1153         if (sk < 0) {
1154                 connman_error("Failed to create %s listener socket", proto);
1155                 return -EIO;
1156         }
1157
1158         if (setsockopt(sk, SOL_SOCKET, SO_BINDTODEVICE,
1159                                         ifname, strlen(ifname) + 1) < 0) {
1160                 connman_error("Failed to bind %s listener interface", proto);
1161                 close(sk);
1162                 return -EIO;
1163         }
1164
1165         memset(&sin, 0, sizeof(sin));
1166         sin.sin_family = AF_INET;
1167         sin.sin_port = htons(53);
1168         sin.sin_addr.s_addr = inet_addr("127.0.0.1");
1169         sin.sin_addr.s_addr = htonl(INADDR_ANY);
1170
1171         if (bind(sk, (struct sockaddr *) &sin, sizeof(sin)) < 0) {
1172                 connman_error("Failed to bind %s listener socket", proto);
1173                 close(sk);
1174                 return -EIO;
1175         }
1176
1177         if (protocol == IPPROTO_TCP && listen(sk, 10) < 0) {
1178                 connman_error("Failed to listen on TCP socket");
1179                 close(sk);
1180                 return -EIO;
1181         }
1182
1183         channel = g_io_channel_unix_new(sk);
1184         if (channel == NULL) {
1185                 connman_error("Failed to create %s listener channel", proto);
1186                 close(sk);
1187                 return -EIO;
1188         }
1189
1190         g_io_channel_set_close_on_unref(channel, TRUE);
1191
1192         if (protocol == IPPROTO_TCP) {
1193                 tcp_listener_channel = channel;
1194                 tcp_listener_watch = g_io_add_watch(channel,
1195                                         G_IO_IN, tcp_listener_event, NULL);
1196         } else {
1197                 udp_listener_channel = channel;
1198                 udp_listener_watch = g_io_add_watch(channel,
1199                                         G_IO_IN, udp_listener_event, NULL);
1200         }
1201
1202         return 0;
1203 }
1204
1205 static void destroy_udp_listener(void)
1206 {
1207         DBG("");
1208
1209         if (udp_listener_watch > 0)
1210                 g_source_remove(udp_listener_watch);
1211
1212         g_io_channel_unref(udp_listener_channel);
1213 }
1214
1215 static void destroy_tcp_listener(void)
1216 {
1217         DBG("");
1218
1219         if (tcp_listener_watch > 0)
1220                 g_source_remove(tcp_listener_watch);
1221
1222         g_io_channel_unref(tcp_listener_channel);
1223 }
1224
1225 static int create_listener(void)
1226 {
1227         int err;
1228
1229         err = create_dns_listener(IPPROTO_UDP);
1230         if (err < 0)
1231                 return err;
1232
1233         err = create_dns_listener(IPPROTO_TCP);
1234         if (err < 0) {
1235                 destroy_udp_listener();
1236                 return err;
1237         }
1238
1239         connman_resolver_append("lo", NULL, "127.0.0.1");
1240
1241         return 0;
1242 }
1243
1244 static void destroy_listener(void)
1245 {
1246         GSList *list;
1247
1248         connman_resolver_remove_all("lo");
1249
1250         for (list = request_pending_list; list; list = list->next) {
1251                 struct request_data *req = list->data;
1252
1253                 DBG("Dropping pending request (id 0x%04x -> 0x%04x)",
1254                                                 req->srcid, req->dstid);
1255
1256                 g_free(req->resp);
1257                 g_free(req->request);
1258                 g_free(req->name);
1259                 g_free(req);
1260                 list->data = NULL;
1261         }
1262
1263         g_slist_free(request_pending_list);
1264         request_pending_list = NULL;
1265
1266         for (list = request_list; list; list = list->next) {
1267                 struct request_data *req = list->data;
1268
1269                 DBG("Dropping request (id 0x%04x -> 0x%04x)",
1270                                                 req->srcid, req->dstid);
1271
1272                 g_free(req->resp);
1273                 g_free(req->request);
1274                 g_free(req->name);
1275                 g_free(req);
1276                 list->data = NULL;
1277         }
1278
1279         g_slist_free(request_list);
1280         request_list = NULL;
1281
1282         destroy_tcp_listener();
1283         destroy_udp_listener();
1284 }
1285
1286 static int dnsproxy_init(void)
1287 {
1288         int err;
1289
1290         err = create_listener();
1291         if (err < 0)
1292                 return err;
1293
1294         err = connman_resolver_register(&dnsproxy_resolver);
1295         if (err < 0)
1296                 goto destroy;
1297
1298         err = connman_notifier_register(&dnsproxy_notifier);
1299         if (err < 0)
1300                 goto unregister;
1301
1302         return 0;
1303
1304 unregister:
1305         connman_resolver_unregister(&dnsproxy_resolver);
1306
1307 destroy:
1308         destroy_listener();
1309
1310         return err;
1311 }
1312
1313 static void dnsproxy_exit(void)
1314 {
1315         connman_notifier_unregister(&dnsproxy_notifier);
1316
1317         connman_resolver_unregister(&dnsproxy_resolver);
1318
1319         destroy_listener();
1320 }
1321
1322 CONNMAN_PLUGIN_DEFINE(dnsproxy, "DNS proxy resolver plugin", VERSION,
1323                  CONNMAN_PLUGIN_PRIORITY_DEFAULT, dnsproxy_init, dnsproxy_exit)