src/vpn/gnunet-service-dns.c

   1 /*
   2      This file is part of GNUnet.
   3      (C) 2009 Christian Grothoff (and other contributing authors)
   4
   5      GNUnet is free software; you can redistribute it and/or modify
   6      it under the terms of the GNU General Public License as published
   7      by the Free Software Foundation; either version 3, or (at your
   8      option) any later version.
   9
  10      GNUnet is distributed in the hope that it will be useful, but
  11      WITHOUT ANY WARRANTY; without even the implied warranty of
  12      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13      General Public License for more details.
  14
  15      You should have received a copy of the GNU General Public License
  16      along with GNUnet; see the file COPYING.  If not, write to the
  17      Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  18      Boston, MA 02111-1307, USA.
  19 */
  20
  21 /**
  22  * @file vpn/gnunet-service-dns.c
  23  * @author Philipp Toelke
  24  */
  25 #include "platform.h"
  26 #include "gnunet_getopt_lib.h"
  27 #include "gnunet_service_lib.h"
  28 #include "gnunet_network_lib.h"
  29 #include "gnunet_os_lib.h"
  30 #include "gnunet-service-dns-p.h"
  31 #include "gnunet_protocols.h"
  32 #include "gnunet_applications.h"
  33 #include "gnunet-vpn-packet.h"
  34 #include "gnunet_container_lib.h"
  35 #include "gnunet-dns-parser.h"
  36 #include "gnunet_dht_service.h"
  37 #include "gnunet_block_lib.h"
  38 #include "block_dns.h"
  39 #include "gnunet_crypto_lib.h"
  40 #include "gnunet_mesh_service.h"
  41 #include "gnunet_signatures.h"
  42
  43 struct GNUNET_MESH_Handle *mesh_handle;
  44
  45 /**
  46  * The UDP-Socket through which DNS-Resolves will be sent if they are not to be
  47  * sent through gnunet. The port of this socket will not be hijacked.
  48  */
  49 static struct GNUNET_NETWORK_Handle *dnsout;
  50
  51 /**
  52  * The port bound to the socket dnsout
  53  */
  54 static unsigned short dnsoutport;
  55
  56 /**
  57  * A handle to the DHT-Service
  58  */
  59 static struct GNUNET_DHT_Handle *dht;
  60
  61 /**
  62  * The configuration to use
  63  */
  64 static const struct GNUNET_CONFIGURATION_Handle *cfg;
  65
  66 /**
  67  * The handle to the service-configuration
  68  */
  69 static struct GNUNET_CONFIGURATION_Handle *servicecfg;
  70
  71 /**
  72  * A list of DNS-Responses that have to be sent to the requesting client
  73  */
  74 static struct answer_packet_list *head;
  75
  76 /**
  77  * The tail of the list of DNS-responses
  78  */
  79 static struct answer_packet_list *tail;
  80
  81 /**
  82  * A structure containing a mapping from network-byte-ordered DNS-id (16 bit) to
  83  * some information needed to handle this query
  84  *
  85  * It currently allocates at least
  86  * (1 + machine-width + 32 + 32 + 16 + machine-width + 8) * 65536 bit
  87  * = 1.7 MiB on 64 bit.
  88  * = 1.2 MiB on 32 bit.
  89  */
  90 static struct {
  91     unsigned valid:1;
  92     struct GNUNET_SERVER_Client* client;
  93     uint32_t local_ip;
  94     uint32_t remote_ip;
  95     uint16_t local_port;
  96     char* name;
  97     uint8_t namelen;
  98 } query_states[UINT16_MAX];
  99
 100 /**
 101  * A struct used to give more than one value as
 102  * closure to receive_dht
 103  */
 104 struct receive_dht_cls {
 105     uint16_t id;
 106     struct GNUNET_DHT_GetHandle* handle;
 107 };
 108
 109 /**
 110  * Hijack all outgoing DNS-Traffic but for traffic leaving "our" port.
 111  */
 112 static void
 113 hijack (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
 114 {
 115   char port_s[6];
 116   char *virt_dns;
 117   struct GNUNET_OS_Process *proc;
 118
 119   if (GNUNET_SYSERR ==
 120       GNUNET_CONFIGURATION_get_value_string (cfg, "vpn", "VIRTDNS",
 121                                              &virt_dns))
 122     {
 123       GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
 124                   "No entry 'VIRTDNS' in configuration!\n");
 125       exit (1);
 126     }
 127
 128   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Hijacking, port is %d\n", dnsoutport);
 129   snprintf (port_s, 6, "%d", dnsoutport);
 130   if (NULL != (proc = GNUNET_OS_start_process (NULL,
 131                                                NULL,
 132                                                "gnunet-helper-hijack-dns",
 133                                                "gnunet-hijack-dns",
 134                                                port_s, virt_dns, NULL)))
 135     GNUNET_OS_process_close (proc);
 136   GNUNET_free (virt_dns);
 137 }
 138
 139 /**
 140  * Delete the hijacking-routes
 141  */
 142 static void
 143 unhijack (unsigned short port)
 144 {
 145   char port_s[6];
 146   char *virt_dns;
 147   struct GNUNET_OS_Process *proc;
 148
 149   if (GNUNET_SYSERR ==
 150       GNUNET_CONFIGURATION_get_value_string (cfg, "vpn", "VIRTDNS",
 151                                              &virt_dns))
 152     {
 153       GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
 154                   "No entry 'VIRTDNS' in configuration!\n");
 155       exit (1);
 156     }
 157
 158   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "unHijacking, port is %d\n", port);
 159   snprintf (port_s, 6, "%d", port);
 160   if (NULL != (proc = GNUNET_OS_start_process (NULL,
 161                                                NULL,
 162                                                "gnunet-helper-hijack-dns",
 163                                                "gnunet-hijack-dns",
 164                                                "-d", port_s, virt_dns, NULL)))
 165     GNUNET_OS_process_close (proc);
 166   GNUNET_free (virt_dns);
 167 }
 168
 169 /**
 170  * Send the DNS-Response to the client. Gets called via the notify_transmit_ready-
 171  * system.
 172  */
 173 static size_t
 174 send_answer(void* cls, size_t size, void* buf) {
 175     struct answer_packet_list* query = head;
 176     size_t len = ntohs(query->pkt.hdr.size);
 177
 178     GNUNET_assert(len <= size);
 179
 180     memcpy(buf, &query->pkt.hdr, len);
 181
 182     GNUNET_CONTAINER_DLL_remove (head, tail, query);
 183
 184     GNUNET_free(query);
 185
 186     /* When more data is to be sent, reschedule */
 187     if (head != NULL)
 188       GNUNET_SERVER_notify_transmit_ready(cls,
 189                                           ntohs(head->pkt.hdr.size),
 190                                           GNUNET_TIME_UNIT_FOREVER_REL,
 191                                           &send_answer,
 192                                           cls);
 193
 194     return len;
 195 }
 196
 197 struct tunnel_cls {
 198     struct GNUNET_MESH_Tunnel *tunnel;
 199     struct GNUNET_MessageHeader hdr;
 200     struct dns_pkt dns;
 201 };
 202
 203 struct tunnel_cls *remote_pending[UINT16_MAX];
 204
 205
 206 static size_t
 207 mesh_send (void *cls, size_t size, void *buf)
 208 {
 209   struct tunnel_cls *cls_ = (struct tunnel_cls *) cls;
 210
 211   GNUNET_assert(cls_->hdr.size <= size);
 212
 213   size = cls_->hdr.size;
 214   cls_->hdr.size = htons(cls_->hdr.size);
 215
 216   memcpy(buf, &cls_->hdr, size);
 217   return size;
 218 }
 219
 220
 221 void mesh_connect (void* cls, const struct GNUNET_PeerIdentity* peer, const struct GNUNET_TRANSPORT_ATS_Information *atsi) {
 222   GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "Connected to peer %x\n", *((unsigned long*)peer));
 223   struct tunnel_cls *cls_ = (struct tunnel_cls*)cls;
 224
 225   GNUNET_MESH_notify_transmit_ready(cls_->tunnel,
 226                                     GNUNET_YES,
 227                                     42,
 228                                     GNUNET_TIME_UNIT_MINUTES,
 229                                     NULL,
 230                                     cls_->hdr.size,
 231                                     mesh_send,
 232                                     cls);
 233 }
 234
 235
 236 static void
 237 send_mesh_query (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
 238 {
 239   if (0 != (tc->reason & GNUNET_SCHEDULER_REASON_SHUTDOWN))
 240     return;
 241
 242   struct tunnel_cls *cls_ = (struct tunnel_cls*)cls;
 243
 244   cls_->tunnel = GNUNET_MESH_peer_request_connect_by_type(mesh_handle,
 245                                            GNUNET_TIME_UNIT_HOURS,
 246                                            GNUNET_APPLICATION_TYPE_INTERNET_RESOLVER,
 247                                            mesh_connect,
 248                                            NULL,
 249                                            cls_);
 250
 251   remote_pending[cls_->dns.s.id] = cls_;
 252 }
 253
 254 static int
 255 receive_mesh_query (void *cls,
 256                     struct GNUNET_MESH_Tunnel *tunnel,
 257                     void **ctx,
 258                     const struct GNUNET_PeerIdentity *sender,
 259                     const struct GNUNET_MessageHeader *message,
 260                     const struct GNUNET_TRANSPORT_ATS_Information *atsi)
 261 {
 262   return GNUNET_SYSERR;
 263 }
 264
 265 static int
 266 receive_mesh_answer (void *cls,
 267                      struct GNUNET_MESH_Tunnel *tunnel,
 268                      void **ctx,
 269                      const struct GNUNET_PeerIdentity *sender,
 270                      const struct GNUNET_MessageHeader *message,
 271                      const struct GNUNET_TRANSPORT_ATS_Information *atsi)
 272 {
 273   /* TODo: size check */
 274   struct dns_pkt *dns = (struct dns_pkt *) (message + 1);
 275
 276   /* They sent us a packet we were not waiting for */
 277   if (remote_pending[dns->s.id] == NULL
 278       || remote_pending[dns->s.id]->tunnel != tunnel)
 279     return GNUNET_SYSERR;
 280   if (query_states[dns->s.id].valid != GNUNET_YES)
 281     return GNUNET_SYSERR;
 282   query_states[dns->s.id].valid = GNUNET_NO;
 283
 284   size_t len = sizeof (struct answer_packet) - 1 + sizeof (struct dns_static) + query_states[dns->s.id].namelen + sizeof (struct dns_query_line) + 2    /* To hold the pointer (as defined in RFC1035) to the name */
 285     + sizeof (struct dns_record_line) - 1 + 16; /* To hold the IPv6-Address */
 286
 287   struct answer_packet_list *answer =
 288     GNUNET_malloc (len + 2 * sizeof (struct answer_packet_list *));
 289   memset (answer, 0, len + 2 * sizeof (struct answer_packet_list *));
 290
 291   answer->pkt.hdr.type = htons (GNUNET_MESSAGE_TYPE_LOCAL_RESPONSE_DNS);
 292   answer->pkt.hdr.size = htons (len);
 293   answer->pkt.subtype = GNUNET_DNS_ANSWER_TYPE_REMOTE;
 294
 295   struct dns_pkt_parsed* pdns = parse_dns_packet(dns);
 296
 297   if (ntohs(pdns->s.ancount) < 1)
 298     {
 299       free_parsed_dns_packet(pdns);
 300       return GNUNET_OK;
 301     }
 302
 303   answer->pkt.addrsize = pdns->answers[0]->data_len;
 304   memcpy(answer->pkt.addr, pdns->answers[0]->data, ntohs(pdns->answers[0]->data_len));
 305
 306   answer->pkt.from = query_states[dns->s.id].remote_ip;
 307
 308   answer->pkt.to = query_states[dns->s.id].local_ip;
 309   answer->pkt.dst_port = query_states[dns->s.id].local_port;
 310
 311   struct dns_pkt *dpkt = (struct dns_pkt *) answer->pkt.data;
 312
 313   dpkt->s.id = dns->s.id;
 314   dpkt->s.aa = 1;
 315   dpkt->s.qr = 1;
 316   dpkt->s.ra = 1;
 317   dpkt->s.qdcount = htons (1);
 318   dpkt->s.ancount = htons (1);
 319
 320   memcpy (dpkt->data, query_states[dns->s.id].name,
 321           query_states[dns->s.id].namelen);
 322   GNUNET_free (query_states[dns->s.id].name);
 323
 324   struct dns_query_line *dque =
 325     (struct dns_query_line *) (dpkt->data +
 326                                (query_states[dns->s.id].namelen));
 327   dque->type = htons (28);      /* AAAA */
 328   dque->class = htons (1);      /* IN */
 329
 330   char *anname =
 331     (char *) (dpkt->data + (query_states[dns->s.id].namelen) +
 332               sizeof (struct dns_query_line));
 333   memcpy (anname, "\xc0\x0c", 2);
 334
 335   struct dns_record_line *drec_data =
 336     (struct dns_record_line *) (dpkt->data +
 337                                 (query_states[dns->s.id].namelen) +
 338                                 sizeof (struct dns_query_line) + 2);
 339   drec_data->type = htons (28); /* AAAA */
 340   drec_data->class = htons (1); /* IN */
 341
 342   drec_data->ttl = pdns->answers[0]->ttl;
 343   drec_data->data_len = htons (16);
 344
 345   /* Calculate at which offset in the packet the IPv6-Address belongs, it is
 346    * filled in by the daemon-vpn */
 347   answer->pkt.addroffset =
 348     htons ((unsigned short) ((unsigned long) (&drec_data->data) -
 349                              (unsigned long) (&answer->pkt)));
 350
 351   GNUNET_CONTAINER_DLL_insert_after (head, tail, tail, answer);
 352
 353   GNUNET_SERVER_notify_transmit_ready (query_states[dns->s.id].client,
 354                                        len,
 355                                        GNUNET_TIME_UNIT_FOREVER_REL,
 356                                        &send_answer,
 357                                        query_states[dns->s.id].client);
 358
 359   free_parsed_dns_packet(pdns);
 360   return GNUNET_OK;
 361 }
 362
 363
 364 static void
 365 send_rev_query(void * cls, const struct GNUNET_SCHEDULER_TaskContext *tc) {
 366     if (0 != (tc->reason & GNUNET_SCHEDULER_REASON_SHUTDOWN))
 367       return;
 368
 369     struct dns_pkt_parsed* pdns = (struct dns_pkt_parsed*) cls;
 370
 371     unsigned short id = pdns->s.id;
 372
 373     free_parsed_dns_packet(pdns);
 374
 375     if (query_states[id].valid != GNUNET_YES) return;
 376     query_states[id].valid = GNUNET_NO;
 377
 378     GNUNET_assert(query_states[id].namelen == 74);
 379
 380     size_t len = sizeof(struct answer_packet) - 1 \
 381                  + sizeof(struct dns_static) \
 382                  + 74 /* this is the length of a reverse ipv6-lookup */ \
 383                  + sizeof(struct dns_query_line) \
 384                  + 2 /* To hold the pointer (as defined in RFC1035) to the name */ \
 385                  + sizeof(struct dns_record_line) - 1 \
 386                  - 2 /* We do not know the lenght of the answer yet*/;
 387
 388     struct answer_packet_list* answer = GNUNET_malloc(len + 2*sizeof(struct answer_packet_list*));
 389     memset(answer, 0, len + 2*sizeof(struct answer_packet_list*));
 390
 391     answer->pkt.hdr.type = htons(GNUNET_MESSAGE_TYPE_LOCAL_RESPONSE_DNS);
 392     answer->pkt.hdr.size = htons(len);
 393     answer->pkt.subtype = GNUNET_DNS_ANSWER_TYPE_REV;
 394
 395     answer->pkt.from = query_states[id].remote_ip;
 396
 397     answer->pkt.to = query_states[id].local_ip;
 398     answer->pkt.dst_port = query_states[id].local_port;
 399
 400     struct dns_pkt *dpkt = (struct dns_pkt*)answer->pkt.data;
 401
 402     dpkt->s.id = id;
 403     dpkt->s.aa = 1;
 404     dpkt->s.qr = 1;
 405     dpkt->s.ra = 1;
 406     dpkt->s.qdcount = htons(1);
 407     dpkt->s.ancount = htons(1);
 408
 409     memcpy(dpkt->data, query_states[id].name, query_states[id].namelen);
 410     GNUNET_free(query_states[id].name);
 411
 412     struct dns_query_line* dque = (struct dns_query_line*)(dpkt->data+(query_states[id].namelen));
 413     dque->type = htons(12); /* PTR */
 414     dque->class = htons(1); /* IN */
 415
 416     char* anname = (char*)(dpkt->data+(query_states[id].namelen)+sizeof(struct dns_query_line));
 417     memcpy(anname, "\xc0\x0c", 2);
 418
 419     struct dns_record_line *drec_data = (struct dns_record_line*)(dpkt->data+(query_states[id].namelen)+sizeof(struct dns_query_line)+2);
 420     drec_data->type = htons(12); /* AAAA */
 421     drec_data->class = htons(1); /* IN */
 422     /* FIXME: read the TTL from block:
 423      * GNUNET_TIME_absolute_get_remaining(rec->expiration_time)
 424      *
 425      * But how to get the seconds out of this?
 426      */
 427     drec_data->ttl = htonl(3600);
 428
 429     /* Calculate at which offset in the packet the length of the name and the
 430      * name, it is filled in by the daemon-vpn */
 431     answer->pkt.addroffset = htons((unsigned short)((unsigned long)(&drec_data->data_len)-(unsigned long)(&answer->pkt)));
 432
 433     GNUNET_CONTAINER_DLL_insert_after(head, tail, tail, answer);
 434
 435     GNUNET_SERVER_notify_transmit_ready(query_states[id].client,
 436                                         len,
 437                                         GNUNET_TIME_UNIT_FOREVER_REL,
 438                                         &send_answer,
 439                                         query_states[id].client);
 440 }
 441
 442 /**
 443  * Receive a block from the dht.
 444  */
 445 static void
 446 receive_dht(void *cls,
 447             struct GNUNET_TIME_Absolute exp,
 448             const GNUNET_HashCode *key,
 449             const struct GNUNET_PeerIdentity *const *get_path,
 450             const struct GNUNET_PeerIdentity *const *put_path,
 451             enum GNUNET_BLOCK_Type type,
 452             size_t size,
 453             const void *data) {
 454
 455     unsigned short id = ((struct receive_dht_cls*)cls)->id;
 456     struct GNUNET_DHT_GetHandle* handle = ((struct receive_dht_cls*)cls)->handle;
 457     GNUNET_free(cls);
 458
 459     GNUNET_assert(type == GNUNET_BLOCK_TYPE_DNS);
 460
 461     /* If no query with this id is pending, ignore the block */
 462     if (query_states[id].valid != GNUNET_YES) return;
 463     query_states[id].valid = GNUNET_NO;
 464
 465     const struct GNUNET_DNS_Record* rec = data;
 466     GNUNET_log(GNUNET_ERROR_TYPE_DEBUG,
 467                "Got block of size %d, peer: %08x, desc: %08x\n",
 468                size,
 469                *((unsigned int*)&rec->peer),
 470                *((unsigned int*)&rec->service_descriptor));
 471
 472     size_t len = sizeof(struct answer_packet) - 1 \
 473                  + sizeof(struct dns_static) \
 474                  + query_states[id].namelen \
 475                  + sizeof(struct dns_query_line) \
 476                  + 2 /* To hold the pointer (as defined in RFC1035) to the name */ \
 477                  + sizeof(struct dns_record_line) - 1 \
 478                  + 16; /* To hold the IPv6-Address */
 479
 480     struct answer_packet_list* answer = GNUNET_malloc(len + 2*sizeof(struct answer_packet_list*));
 481     memset(answer, 0, len + 2*sizeof(struct answer_packet_list*));
 482
 483     answer->pkt.hdr.type = htons(GNUNET_MESSAGE_TYPE_LOCAL_RESPONSE_DNS);
 484     answer->pkt.hdr.size = htons(len);
 485     answer->pkt.subtype = GNUNET_DNS_ANSWER_TYPE_SERVICE;
 486
 487     GNUNET_CRYPTO_hash(&rec->peer,
 488                        sizeof(struct GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded),
 489                        &answer->pkt.service_descr.peer);
 490
 491     memcpy(&answer->pkt.service_descr.service_descriptor,
 492            &rec->service_descriptor,
 493            sizeof(GNUNET_HashCode));
 494     memcpy(&answer->pkt.service_descr.service_type,
 495            &rec->service_type,
 496            sizeof(answer->pkt.service_descr.service_type));
 497     memcpy(&answer->pkt.service_descr.ports, &rec->ports, sizeof(answer->pkt.service_descr.ports));
 498
 499     answer->pkt.from = query_states[id].remote_ip;
 500
 501     answer->pkt.to = query_states[id].local_ip;
 502     answer->pkt.dst_port = query_states[id].local_port;
 503
 504     struct dns_pkt *dpkt = (struct dns_pkt*)answer->pkt.data;
 505
 506     dpkt->s.id = id;
 507     dpkt->s.aa = 1;
 508     dpkt->s.qr = 1;
 509     dpkt->s.ra = 1;
 510     dpkt->s.qdcount = htons(1);
 511     dpkt->s.ancount = htons(1);
 512
 513     memcpy(dpkt->data, query_states[id].name, query_states[id].namelen);
 514     GNUNET_free(query_states[id].name);
 515
 516     struct dns_query_line* dque = (struct dns_query_line*)(dpkt->data+(query_states[id].namelen));
 517     dque->type = htons(28); /* AAAA */
 518     dque->class = htons(1); /* IN */
 519
 520     char* anname = (char*)(dpkt->data+(query_states[id].namelen)+sizeof(struct dns_query_line));
 521     memcpy(anname, "\xc0\x0c", 2);
 522
 523     struct dns_record_line *drec_data = (struct dns_record_line*)(dpkt->data+(query_states[id].namelen)+sizeof(struct dns_query_line)+2);
 524     drec_data->type = htons(28); /* AAAA */
 525     drec_data->class = htons(1); /* IN */
 526
 527     /* FIXME: read the TTL from block:
 528      * GNUNET_TIME_absolute_get_remaining(rec->expiration_time)
 529      *
 530      * But how to get the seconds out of this?
 531      */
 532     drec_data->ttl = htonl(3600);
 533     drec_data->data_len = htons(16);
 534
 535     /* Calculate at which offset in the packet the IPv6-Address belongs, it is
 536      * filled in by the daemon-vpn */
 537     answer->pkt.addroffset = htons((unsigned short)((unsigned long)(&drec_data->data)-(unsigned long)(&answer->pkt)));
 538
 539     GNUNET_CONTAINER_DLL_insert_after(head, tail, tail, answer);
 540
 541     GNUNET_SERVER_notify_transmit_ready(query_states[id].client,
 542                                         len,
 543                                         GNUNET_TIME_UNIT_FOREVER_REL,
 544                                         &send_answer,
 545                                         query_states[id].client);
 546
 547     GNUNET_DHT_get_stop(handle);
 548 }
 549
 550 /**
 551  * This receives a GNUNET_MESSAGE_TYPE_REHIJACK and rehijacks the DNS
 552  */
 553 static void
 554 rehijack(void *cls,
 555          struct GNUNET_SERVER_Client *client,
 556          const struct GNUNET_MessageHeader *message) {
 557     unhijack(dnsoutport);
 558     GNUNET_SCHEDULER_add_delayed(GNUNET_TIME_UNIT_SECONDS, hijack, NULL);
 559
 560     GNUNET_SERVER_receive_done(client, GNUNET_OK);
 561 }
 562
 563 /**
 564  * This receives the dns-payload from the daemon-vpn and sends it on over the udp-socket
 565  */
 566 static void
 567 receive_query(void *cls,
 568               struct GNUNET_SERVER_Client *client,
 569               const struct GNUNET_MessageHeader *message) {
 570     struct query_packet* pkt = (struct query_packet*)message;
 571     struct dns_pkt* dns = (struct dns_pkt*)pkt->data;
 572     struct dns_pkt_parsed* pdns = parse_dns_packet(dns);
 573
 574     query_states[dns->s.id].valid = GNUNET_YES;
 575     query_states[dns->s.id].client = client;
 576     query_states[dns->s.id].local_ip = pkt->orig_from;
 577     query_states[dns->s.id].local_port = pkt->src_port;
 578     query_states[dns->s.id].remote_ip = pkt->orig_to;
 579     query_states[dns->s.id].namelen = strlen((char*)dns->data) + 1;
 580     query_states[dns->s.id].name = GNUNET_malloc(query_states[dns->s.id].namelen);
 581     memcpy(query_states[dns->s.id].name, dns->data, query_states[dns->s.id].namelen);
 582
 583     /* The query is for a .gnunet-address */
 584     if (pdns->queries[0]->namelen > 9 &&
 585         0 == strncmp(pdns->queries[0]->name+(pdns->queries[0]->namelen - 9), ".gnunet.", 9))
 586       {
 587         GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "Query for .gnunet!\n");
 588         GNUNET_HashCode key;
 589         GNUNET_CRYPTO_hash(pdns->queries[0]->name, pdns->queries[0]->namelen, &key);
 590
 591         GNUNET_log(GNUNET_ERROR_TYPE_DEBUG,
 592                    "Getting with key %08x, len is %d\n",
 593                    *((unsigned int*)&key),
 594                    pdns->queries[0]->namelen);
 595
 596         struct receive_dht_cls* cls = GNUNET_malloc(sizeof(struct receive_dht_cls));
 597         cls->id = dns->s.id;
 598
 599         cls->handle = GNUNET_DHT_get_start(dht,
 600                                            GNUNET_TIME_UNIT_MINUTES,
 601                                            GNUNET_BLOCK_TYPE_DNS,
 602                                            &key,
 603                                            DEFAULT_GET_REPLICATION,
 604                                            GNUNET_DHT_RO_NONE,
 605                                            NULL,
 606                                            0,
 607                                            NULL,
 608                                            0,
 609                                            receive_dht,
 610                                            cls);
 611
 612         goto outfree;
 613       }
 614
 615     GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "Query for '%s'; namelen=%d\n", pdns->queries[0]->name, pdns->queries[0]->namelen);
 616
 617     /* This is a PTR-Query. Check if it is for "our" network */
 618     if (htons(pdns->queries[0]->qtype) == 12 &&
 619         74 == pdns->queries[0]->namelen)
 620       {
 621         char* ipv6addr;
 622         char ipv6[16];
 623         char ipv6rev[74] = "X.X.X.X.X.X.X.X.X.X.X.X.X.X.X.X.X.X.X.X.X.X.X.X.X.X.X.X.X.X.X.X.ip6.arpa.";
 624         unsigned int i;
 625         unsigned long long ipv6prefix;
 626         unsigned int comparelen;
 627
 628         GNUNET_assert(GNUNET_OK == GNUNET_CONFIGURATION_get_value_string(cfg, "vpn", "IPV6ADDR", &ipv6addr));
 629         inet_pton (AF_INET6, ipv6addr, ipv6);
 630         GNUNET_free(ipv6addr);
 631
 632         GNUNET_assert(GNUNET_OK == GNUNET_CONFIGURATION_get_value_number(cfg, "vpn", "IPV6PREFIX", &ipv6prefix));
 633         GNUNET_assert(ipv6prefix < 127);
 634         ipv6prefix = (ipv6prefix + 7)/8;
 635
 636         for (i = ipv6prefix; i < 16; i++)
 637           ipv6[i] = 0;
 638
 639         for (i = 0; i < 16; i++)
 640           {
 641             unsigned char c1 = ipv6[i] >> 4;
 642             unsigned char c2 = ipv6[i] & 0xf;
 643
 644             if (c1 <= 9)
 645               ipv6rev[62-(4*i)] = c1 + '0';
 646             else
 647               ipv6rev[62-(4*i)] = c1 + 87; /* 87 is the difference between 'a' and 10 */
 648
 649             if (c2 <= 9)
 650               ipv6rev[62-((4*i)+2)] = c2 + '0';
 651             else
 652               ipv6rev[62-((4*i)+2)] = c2 + 87;
 653           }
 654         GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "My network is %s'.\n", ipv6rev);
 655         comparelen = 10 + 4*ipv6prefix;
 656         if(0 == strncmp(pdns->queries[0]->name+(pdns->queries[0]->namelen - comparelen),
 657                         ipv6rev + (74 - comparelen),
 658                         comparelen))
 659           {
 660             GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "Reverse-Query for .gnunet!\n");
 661
 662             GNUNET_SCHEDULER_add_now(send_rev_query, pdns);
 663
 664             goto out;
 665           }
 666       }
 667
 668     char* virt_dns;
 669     int virt_dns_bytes;
 670     if (GNUNET_SYSERR ==
 671         GNUNET_CONFIGURATION_get_value_string (cfg, "vpn", "VIRTDNS",
 672                                                &virt_dns))
 673       {
 674         GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
 675                     "No entry 'VIRTDNS' in configuration!\n");
 676         exit (1);
 677       }
 678
 679     if (1 != inet_pton (AF_INET, virt_dns, &virt_dns_bytes))
 680       {
 681         GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
 682                     "Error parsing 'VIRTDNS': %s; %m!\n", virt_dns);
 683         exit(1);
 684       }
 685
 686     GNUNET_free(virt_dns);
 687
 688     if (virt_dns_bytes == pkt->orig_to)
 689       {
 690         /* This is a packet that was sent directly to the virtual dns-server
 691          *
 692          * This means we have to send this query over gnunet
 693          */
 694
 695         size_t size = sizeof(struct GNUNET_MESH_Tunnel*) + sizeof(struct GNUNET_MessageHeader) + (ntohs(message->size) - sizeof(struct query_packet) + 1);
 696         struct tunnel_cls *cls_ =  GNUNET_malloc(size);
 697         cls_->hdr.size = size - sizeof(struct GNUNET_MESH_Tunnel*);
 698
 699         cls_->hdr.type = ntohs(GNUNET_MESSAGE_TYPE_REMOTE_QUERY_DNS);
 700
 701         memcpy(&cls_->dns, dns, cls_->hdr.size);
 702         GNUNET_SCHEDULER_add_now(send_mesh_query, cls_);
 703
 704         goto out;
 705       }
 706
 707
 708     /* The query should be sent to the network */
 709
 710     struct sockaddr_in dest;
 711     memset(&dest, 0, sizeof dest);
 712     dest.sin_port = htons(53);
 713     dest.sin_addr.s_addr = pkt->orig_to;
 714
 715     GNUNET_NETWORK_socket_sendto(dnsout,
 716                                  dns,
 717                                  ntohs(pkt->hdr.size) - sizeof(struct query_packet) + 1,
 718                                  (struct sockaddr*) &dest,
 719                                  sizeof dest);
 720
 721 outfree:
 722     free_parsed_dns_packet(pdns);
 723     pdns = NULL;
 724 out:
 725     GNUNET_SERVER_receive_done(client, GNUNET_OK);
 726 }
 727
 728 static void read_response (void *cls,
 729                            const struct GNUNET_SCHEDULER_TaskContext *tc);
 730
 731 static void
 732 open_port ()
 733 {
 734   struct sockaddr_in addr;
 735
 736   dnsout = GNUNET_NETWORK_socket_create (AF_INET, SOCK_DGRAM, 0);
 737   if (dnsout == NULL)
 738     return;
 739   memset (&addr, 0, sizeof (struct sockaddr_in));
 740
 741   int err = GNUNET_NETWORK_socket_bind (dnsout,
 742                                         (struct sockaddr *) &addr,
 743                                         sizeof (struct sockaddr_in));
 744
 745   if (err != GNUNET_YES)
 746     {
 747       GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
 748                   "Could not bind a port, exiting\n");
 749       return;
 750     }
 751
 752   /* Read the port we bound to */
 753   socklen_t addrlen = sizeof (struct sockaddr_in);
 754   err = getsockname (GNUNET_NETWORK_get_fd (dnsout),
 755                      (struct sockaddr *) &addr, &addrlen);
 756
 757   dnsoutport = htons (addr.sin_port);
 758
 759   GNUNET_SCHEDULER_add_read_net (GNUNET_TIME_UNIT_FOREVER_REL, dnsout,
 760                                  &read_response, NULL);
 761 }
 762
 763 /**
 764  * Read a response-packet of the UDP-Socket
 765  */
 766 static void
 767 read_response (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc) {
 768     struct sockaddr_in addr;
 769     socklen_t addrlen = sizeof (addr);
 770     int r;
 771     int len;
 772
 773     if (tc->reason & GNUNET_SCHEDULER_REASON_SHUTDOWN)
 774       return;
 775
 776     memset(&addr, 0, sizeof addr);
 777
 778 #ifndef MINGW
 779     if (0 != ioctl (GNUNET_NETWORK_get_fd (dnsout),
 780                     FIONREAD, &len))
 781       {
 782         unhijack(dnsoutport);
 783         open_port();
 784         GNUNET_SCHEDULER_add_delayed(GNUNET_TIME_UNIT_SECONDS, hijack, NULL);
 785         return;
 786       }
 787 #else
 788     /* port the code above? */
 789     len = 65536;
 790 #endif
 791     {
 792       unsigned char buf[len];
 793       struct dns_pkt* dns = (struct dns_pkt*)buf;
 794
 795       r = GNUNET_NETWORK_socket_recvfrom (dnsout,
 796                                           buf,
 797                                           sizeof (buf),
 798                                           (struct sockaddr*)&addr,
 799                                           &addrlen);
 800
 801       if (r < 0)
 802         {
 803           unhijack(dnsoutport);
 804           open_port();
 805           GNUNET_SCHEDULER_add_delayed(GNUNET_TIME_UNIT_SECONDS, hijack, NULL);
 806           return;
 807         }
 808
 809       if (query_states[dns->s.id].valid == GNUNET_YES)
 810         {
 811           query_states[dns->s.id].valid = GNUNET_NO;
 812
 813           size_t len = sizeof(struct answer_packet) + r - 1; /* 1 for the unsigned char data[1]; */
 814           struct answer_packet_list* answer = GNUNET_malloc(len + 2*sizeof(struct answer_packet_list*));
 815           answer->pkt.hdr.type = htons(GNUNET_MESSAGE_TYPE_LOCAL_RESPONSE_DNS);
 816           answer->pkt.hdr.size = htons(len);
 817           answer->pkt.subtype = GNUNET_DNS_ANSWER_TYPE_IP;
 818           answer->pkt.from = addr.sin_addr.s_addr;
 819           answer->pkt.to = query_states[dns->s.id].local_ip;
 820           answer->pkt.dst_port = query_states[dns->s.id].local_port;
 821           memcpy(answer->pkt.data, buf, r);
 822
 823           GNUNET_CONTAINER_DLL_insert_after(head, tail, tail, answer);
 824
 825           GNUNET_SERVER_notify_transmit_ready(query_states[dns->s.id].client,
 826                                               len,
 827                                               GNUNET_TIME_UNIT_FOREVER_REL,
 828                                               &send_answer,
 829                                               query_states[dns->s.id].client);
 830         }
 831     }
 832     GNUNET_SCHEDULER_add_read_net(GNUNET_TIME_UNIT_FOREVER_REL,
 833                                   dnsout,
 834                                   &read_response,
 835                                   NULL);
 836 }
 837
 838
 839 /**
 840  * Task run during shutdown.
 841  *
 842  * @param cls unused
 843  * @param tc unused
 844  */
 845 static void
 846 cleanup_task (void *cls,
 847               const struct GNUNET_SCHEDULER_TaskContext *tc)
 848 {
 849   unhijack(dnsoutport);
 850   GNUNET_DHT_disconnect(dht);
 851 }
 852
 853 /**
 854  * @brief Create a port-map from udp and tcp redirects
 855  *
 856  * @param udp_redirects
 857  * @param tcp_redirects
 858  *
 859  * @return
 860  */
 861 uint64_t
 862 get_port_from_redirects (const char *udp_redirects, const char *tcp_redirects)
 863 {
 864   uint64_t ret = 0;
 865   char* cpy, *hostname, *redirect;
 866   int local_port, count = 0;
 867
 868   if (NULL != udp_redirects)
 869     {
 870       cpy = GNUNET_strdup (udp_redirects);
 871       for (redirect = strtok (cpy, " "); redirect != NULL; redirect = strtok (NULL, " "))
 872         {
 873           if (NULL == (hostname = strstr (redirect, ":")))
 874             {
 875               GNUNET_log(GNUNET_ERROR_TYPE_WARNING, "Warning: option %s is not formatted correctly!\n", redirect);
 876               continue;
 877             }
 878           hostname[0] = '\0';
 879           local_port = atoi (redirect);
 880           if (!((local_port > 0) && (local_port < 65536)))
 881             GNUNET_log(GNUNET_ERROR_TYPE_WARNING, "Warning: %s is not a correct port.", redirect);
 882
 883           ret |= (0xFFFF & htons(local_port));
 884           ret <<= 16;
 885           count ++;
 886
 887           if(count > 4)
 888             {
 889               ret = 0;
 890               goto out;
 891             }
 892         }
 893       GNUNET_free(cpy);
 894       cpy = NULL;
 895     }
 896
 897   if (NULL != tcp_redirects)
 898     {
 899       cpy = GNUNET_strdup (tcp_redirects);
 900       for (redirect = strtok (cpy, " "); redirect != NULL; redirect = strtok (NULL, " "))
 901         {
 902           if (NULL == (hostname = strstr (redirect, ":")))
 903             {
 904               GNUNET_log(GNUNET_ERROR_TYPE_WARNING, "Warning: option %s is not formatted correctly!\n", redirect);
 905               continue;
 906             }
 907           hostname[0] = '\0';
 908           local_port = atoi (redirect);
 909           if (!((local_port > 0) && (local_port < 65536)))
 910             GNUNET_log(GNUNET_ERROR_TYPE_WARNING, "Warning: %s is not a correct port.", redirect);
 911
 912           ret |= (0xFFFF & htons(local_port));
 913           ret <<= 16;
 914           count ++;
 915
 916           if(count > 4)
 917             {
 918               ret = 0;
 919               goto out;
 920             }
 921         }
 922       GNUNET_free(cpy);
 923       cpy = NULL;
 924     }
 925
 926 out:
 927   if (NULL != cpy)
 928     GNUNET_free(cpy);
 929   return ret;
 930 }
 931
 932 void
 933 publish_name (const char *name, uint64_t ports, uint32_t service_type,
 934               struct GNUNET_CRYPTO_RsaPrivateKey *my_private_key)
 935 {
 936   size_t size = sizeof (struct GNUNET_DNS_Record);
 937   struct GNUNET_DNS_Record data;
 938   memset (&data, 0, size);
 939
 940   data.purpose.size =
 941     htonl (size - sizeof (struct GNUNET_CRYPTO_RsaSignature));
 942   data.purpose.purpose = GNUNET_SIGNATURE_PURPOSE_DNS_RECORD;
 943
 944   GNUNET_CRYPTO_hash (name, strlen (name) + 1, &data.service_descriptor);
 945   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Store with key1 %x\n",
 946               *((unsigned long long *) &data.service_descriptor));
 947
 948   data.service_type = service_type;
 949   data.ports = ports;
 950
 951   GNUNET_CRYPTO_rsa_key_get_public (my_private_key, &data.peer);
 952
 953   data.expiration_time =
 954     GNUNET_TIME_relative_to_absolute (GNUNET_TIME_relative_multiply(GNUNET_TIME_UNIT_HOURS, 2));
 955
 956   /* Sign the block */
 957   if (GNUNET_OK != GNUNET_CRYPTO_rsa_sign (my_private_key,
 958                                            &data.purpose, &data.signature))
 959     {
 960       GNUNET_log (GNUNET_ERROR_TYPE_ERROR, "could not sign DNS_Record\n");
 961       return;
 962     }
 963
 964   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 965               "Putting with key %08x, size = %d\n",
 966               *((unsigned int *) &data.service_descriptor), size);
 967
 968   GNUNET_DHT_put (dht,
 969                   &data.service_descriptor,
 970                   DEFAULT_PUT_REPLICATION,
 971                   GNUNET_DHT_RO_NONE,
 972                   GNUNET_BLOCK_TYPE_DNS,
 973                   size,
 974                   (char *) &data,
 975                   GNUNET_TIME_relative_to_absolute (GNUNET_TIME_UNIT_HOURS),
 976                   GNUNET_TIME_UNIT_MINUTES, NULL, NULL);
 977 }
 978
 979 /**
 980  * @brief Publishes the record defined by the section section
 981  *
 982  * @param cls closure
 983  * @param section the current section
 984  */
 985 void
 986 publish_iterate (void *cls, const char *section)
 987 {
 988   char *udp_redirects, *tcp_redirects, *alternative_names, *alternative_name,
 989     *keyfile;
 990
 991   GNUNET_CONFIGURATION_get_value_string (servicecfg, section,
 992                                          "UDP_REDIRECTS", &udp_redirects);
 993   GNUNET_CONFIGURATION_get_value_string (servicecfg, section, "TCP_REDIRECTS",
 994                                          &tcp_redirects);
 995
 996   if (GNUNET_OK != GNUNET_CONFIGURATION_get_value_filename (cfg, "GNUNETD",
 997                                                             "HOSTKEY",
 998                                                             &keyfile))
 999     {
1000       GNUNET_log (GNUNET_ERROR_TYPE_ERROR, "could not read keyfile-value\n");
1001       if (keyfile != NULL)
1002         GNUNET_free (keyfile);
1003       return;
1004     }
1005
1006   struct GNUNET_CRYPTO_RsaPrivateKey *my_private_key =
1007     GNUNET_CRYPTO_rsa_key_create_from_file (keyfile);
1008   GNUNET_free (keyfile);
1009   GNUNET_assert (my_private_key != NULL);
1010
1011   uint64_t ports = get_port_from_redirects (udp_redirects, tcp_redirects);
1012   uint32_t service_type = 0;
1013
1014   if (NULL != udp_redirects)
1015     service_type = GNUNET_DNS_SERVICE_TYPE_UDP;
1016
1017   if (NULL != tcp_redirects)
1018     service_type |= GNUNET_DNS_SERVICE_TYPE_TCP;
1019
1020   service_type = htonl (service_type);
1021
1022
1023   publish_name (section, ports, service_type, my_private_key);
1024
1025   GNUNET_CONFIGURATION_get_value_string (servicecfg, section,
1026                                          "ALTERNATIVE_NAMES",
1027                                          &alternative_names);
1028   for (alternative_name = strtok (alternative_names, " ");
1029        alternative_name != NULL; alternative_name = strtok (NULL, " "))
1030     {
1031       char *altname =
1032         alloca (strlen (alternative_name) + strlen (section) + 1 + 1);
1033       strcpy (altname, alternative_name);
1034       strcpy (altname + strlen (alternative_name) + 1, section);
1035       altname[strlen (alternative_name)] = '.';
1036
1037       publish_name (altname, ports, service_type, my_private_key);
1038     }
1039
1040   GNUNET_free_non_null(alternative_names);
1041   GNUNET_CRYPTO_rsa_key_free (my_private_key);
1042   GNUNET_free_non_null (udp_redirects);
1043   GNUNET_free_non_null (tcp_redirects);
1044 }
1045
1046 /**
1047  * Publish a DNS-record in the DHT. This is up to now just for testing.
1048  */
1049 static void
1050 publish_names (void *cls,
1051                const struct GNUNET_SCHEDULER_TaskContext *tc) {
1052     char *services;
1053     if (0 != (tc->reason & GNUNET_SCHEDULER_REASON_SHUTDOWN))
1054       return;
1055
1056     if (NULL != servicecfg)
1057       GNUNET_CONFIGURATION_destroy(servicecfg);
1058
1059     GNUNET_CONFIGURATION_get_value_filename(cfg, "dns", "SERVICES", &services);
1060
1061     servicecfg = GNUNET_CONFIGURATION_create();
1062     if (GNUNET_OK == GNUNET_CONFIGURATION_parse(servicecfg, services))
1063       {
1064         GNUNET_log(GNUNET_ERROR_TYPE_INFO, "Parsing services %s\n", services);
1065         GNUNET_CONFIGURATION_iterate_sections(servicecfg, publish_iterate, NULL);
1066       }
1067     if (NULL != services)
1068       GNUNET_free(services);
1069
1070     GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_UNIT_HOURS,
1071                                   publish_names,
1072                                   NULL);
1073 }
1074
1075 /**
1076  * @param cls closure
1077  * @param server the initialized server
1078  * @param cfg_ configuration to use
1079  */
1080 static void
1081 run (void *cls,
1082      struct GNUNET_SERVER_Handle *server,
1083      const struct GNUNET_CONFIGURATION_Handle *cfg_)
1084 {
1085   static const struct GNUNET_SERVER_MessageHandler handlers[] = {
1086     /* callback, cls, type, size */
1087     {&receive_query, NULL, GNUNET_MESSAGE_TYPE_LOCAL_QUERY_DNS, 0},
1088     {&rehijack, NULL, GNUNET_MESSAGE_TYPE_REHIJACK,
1089      sizeof (struct GNUNET_MessageHeader)},
1090     {NULL, NULL, 0, 0}
1091   };
1092
1093   static struct GNUNET_MESH_MessageHandler *mesh_handlers;
1094
1095   if (GNUNET_YES == GNUNET_CONFIGURATION_get_value_yesno(cfg_, "dns", "PROVIDE_EXIT"))
1096     mesh_handlers = (struct GNUNET_MESH_MessageHandler[]) {
1097           {receive_mesh_query, GNUNET_MESSAGE_TYPE_REMOTE_QUERY_DNS, 0},
1098           {NULL, 0, 0}
1099     };
1100   else
1101     mesh_handlers = (struct GNUNET_MESH_MessageHandler[]) {
1102           {receive_mesh_answer, GNUNET_MESSAGE_TYPE_REMOTE_ANSWER_DNS, 0},
1103           {NULL, 0, 0}
1104     };
1105
1106   const static GNUNET_MESH_ApplicationType apptypes[] =
1107     { GNUNET_APPLICATION_TYPE_INTERNET_RESOLVER,
1108     GNUNET_APPLICATION_TYPE_END
1109   };
1110
1111   mesh_handle = GNUNET_MESH_connect (cfg_, NULL, NULL, mesh_handlers, apptypes);
1112
1113   cfg = cfg_;
1114
1115   unsigned int i;
1116   for (i = 0; i < 65536; i++)
1117     {
1118       query_states[i].valid = GNUNET_NO;
1119     }
1120
1121   dht = GNUNET_DHT_connect (cfg, 1024);
1122
1123   open_port ();
1124
1125   GNUNET_SCHEDULER_add_now (publish_names, NULL);
1126
1127   GNUNET_SERVER_add_handlers (server, handlers);
1128   GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_UNIT_FOREVER_REL,
1129                                 &cleanup_task, cls);
1130 }
1131
1132 /**
1133  * The main function for the dns service.
1134  *
1135  * @param argc number of arguments from the command line
1136  * @param argv command line arguments
1137  * @return 0 ok, 1 on error
1138  */
1139 int
1140 main (int argc, char *const *argv)
1141 {
1142   return (GNUNET_OK ==
1143           GNUNET_SERVICE_run (argc,
1144                               argv,
1145                               "dns",
1146                               GNUNET_SERVICE_OPTION_NONE,
1147                               &run, NULL)) ? 0 : 1;
1148 }