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-vpn-packet.h"
  33 #include "gnunet_container_lib.h"
  34 #include "gnunet-dns-parser.h"
  35 #include "gnunet_dht_service.h"
  36 #include "gnunet_block_lib.h"
  37 #include "block_dns.h"
  38 #include "gnunet_crypto_lib.h"
  39 #include "gnunet_signatures.h"
  40
  41 /**
  42  * The UDP-Socket through which DNS-Resolves will be sent if they are not to be
  43  * sent through gnunet. The port of this socket will not be hijacked.
  44  */
  45 static struct GNUNET_NETWORK_Handle *dnsout;
  46
  47 /**
  48  * The port bound to the socket dnsout
  49  */
  50 static unsigned short dnsoutport;
  51
  52 /**
  53  * A handle to the DHT-Service
  54  */
  55 static struct GNUNET_DHT_Handle *dht;
  56
  57 /**
  58  * The configuration to use
  59  */
  60 static const struct GNUNET_CONFIGURATION_Handle *cfg;
  61
  62 /**
  63  * The handle to the service-configuration
  64  */
  65 static struct GNUNET_CONFIGURATION_Handle *servicecfg;
  66
  67 /**
  68  * A list of DNS-Responses that have to be sent to the requesting client
  69  */
  70 static struct answer_packet_list *head;
  71
  72 /**
  73  * The tail of the list of DNS-responses
  74  */
  75 static struct answer_packet_list *tail;
  76
  77 /**
  78  * A structure containing a mapping from network-byte-ordered DNS-id (16 bit) to
  79  * some information needed to handle this query
  80  *
  81  * It currently allocates at least
  82  * (1 + machine-width + 32 + 32 + 16 + machine-width + 8) * 65536 bit
  83  * = 1.7 MiB on 64 bit.
  84  * = 1.2 MiB on 32 bit.
  85  */
  86 static struct {
  87     unsigned valid:1;
  88     struct GNUNET_SERVER_Client* client;
  89     uint32_t local_ip;
  90     uint32_t remote_ip;
  91     uint16_t local_port;
  92     char* name;
  93     uint8_t namelen;
  94 } query_states[UINT16_MAX];
  95
  96 /**
  97  * A struct used to give more than one value as
  98  * closure to receive_dht
  99  */
 100 struct receive_dht_cls {
 101     uint16_t id;
 102     struct GNUNET_DHT_GetHandle* handle;
 103 };
 104
 105 /**
 106  * Hijack all outgoing DNS-Traffic but for traffic leaving "our" port.
 107  */
 108 static void
 109 hijack (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
 110 {
 111   char port_s[6];
 112   char *virt_dns;
 113   struct GNUNET_OS_Process *proc;
 114
 115   if (GNUNET_SYSERR ==
 116       GNUNET_CONFIGURATION_get_value_string (cfg, "vpn", "VIRTDNS",
 117                                              &virt_dns))
 118     {
 119       GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
 120                   "No entry 'VIRTDNS' in configuration!\n");
 121       exit (1);
 122     }
 123
 124   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Hijacking, port is %d\n", dnsoutport);
 125   snprintf (port_s, 6, "%d", dnsoutport);
 126   if (NULL != (proc = GNUNET_OS_start_process (NULL,
 127                                                NULL,
 128                                                "gnunet-helper-hijack-dns",
 129                                                "gnunet-hijack-dns",
 130                                                port_s, virt_dns, NULL)))
 131     GNUNET_OS_process_close (proc);
 132   GNUNET_free (virt_dns);
 133 }
 134
 135 /**
 136  * Delete the hijacking-routes
 137  */
 138 static void
 139 unhijack (unsigned short port)
 140 {
 141   char port_s[6];
 142   char *virt_dns;
 143   struct GNUNET_OS_Process *proc;
 144
 145   if (GNUNET_SYSERR ==
 146       GNUNET_CONFIGURATION_get_value_string (cfg, "vpn", "VIRTDNS",
 147                                              &virt_dns))
 148     {
 149       GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
 150                   "No entry 'VIRTDNS' in configuration!\n");
 151       exit (1);
 152     }
 153
 154   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "unHijacking, port is %d\n", port);
 155   snprintf (port_s, 6, "%d", port);
 156   if (NULL != (proc = GNUNET_OS_start_process (NULL,
 157                                                NULL,
 158                                                "gnunet-helper-hijack-dns",
 159                                                "gnunet-hijack-dns",
 160                                                "-d", port_s, virt_dns, NULL)))
 161     GNUNET_OS_process_close (proc);
 162   GNUNET_free (virt_dns);
 163 }
 164
 165 /**
 166  * Send the DNS-Response to the client. Gets called via the notify_transmit_ready-
 167  * system.
 168  */
 169 static size_t
 170 send_answer(void* cls, size_t size, void* buf) {
 171     struct answer_packet_list* query = head;
 172     size_t len = ntohs(query->pkt.hdr.size);
 173
 174     GNUNET_assert(len <= size);
 175
 176     memcpy(buf, &query->pkt.hdr, len);
 177
 178     GNUNET_CONTAINER_DLL_remove (head, tail, query);
 179
 180     GNUNET_free(query);
 181
 182     /* When more data is to be sent, reschedule */
 183     if (head != NULL)
 184       GNUNET_SERVER_notify_transmit_ready(cls,
 185                                           ntohs(head->pkt.hdr.size),
 186                                           GNUNET_TIME_UNIT_FOREVER_REL,
 187                                           &send_answer,
 188                                           cls);
 189
 190     return len;
 191 }
 192
 193 static void
 194 send_rev_query(void * cls, const struct GNUNET_SCHEDULER_TaskContext *tc) {
 195     struct dns_pkt_parsed* pdns = (struct dns_pkt_parsed*) cls;
 196
 197     unsigned short id = pdns->s.id;
 198
 199     free_parsed_dns_packet(pdns);
 200
 201     if (query_states[id].valid != GNUNET_YES) return;
 202     query_states[id].valid = GNUNET_NO;
 203
 204     GNUNET_assert(query_states[id].namelen == 74);
 205
 206     size_t len = sizeof(struct answer_packet) - 1 \
 207                  + sizeof(struct dns_static) \
 208                  + 74 /* this is the length of a reverse ipv6-lookup */ \
 209                  + sizeof(struct dns_query_line) \
 210                  + 2 /* To hold the pointer (as defined in RFC1035) to the name */ \
 211                  + sizeof(struct dns_record_line) - 1 \
 212                  - 2 /* We do not know the lenght of the answer yet*/;
 213
 214     struct answer_packet_list* answer = GNUNET_malloc(len + 2*sizeof(struct answer_packet_list*));
 215     memset(answer, 0, len + 2*sizeof(struct answer_packet_list*));
 216
 217     answer->pkt.hdr.type = htons(GNUNET_MESSAGE_TYPE_LOCAL_RESPONSE_DNS);
 218     answer->pkt.hdr.size = htons(len);
 219     answer->pkt.subtype = GNUNET_DNS_ANSWER_TYPE_REV;
 220
 221     answer->pkt.from = query_states[id].remote_ip;
 222
 223     answer->pkt.to = query_states[id].local_ip;
 224     answer->pkt.dst_port = query_states[id].local_port;
 225
 226     struct dns_pkt *dpkt = (struct dns_pkt*)answer->pkt.data;
 227
 228     dpkt->s.id = id;
 229     dpkt->s.aa = 1;
 230     dpkt->s.qr = 1;
 231     dpkt->s.ra = 1;
 232     dpkt->s.qdcount = htons(1);
 233     dpkt->s.ancount = htons(1);
 234
 235     memcpy(dpkt->data, query_states[id].name, query_states[id].namelen);
 236     GNUNET_free(query_states[id].name);
 237
 238     struct dns_query_line* dque = (struct dns_query_line*)(dpkt->data+(query_states[id].namelen));
 239     dque->type = htons(12); /* PTR */
 240     dque->class = htons(1); /* IN */
 241
 242     char* anname = (char*)(dpkt->data+(query_states[id].namelen)+sizeof(struct dns_query_line));
 243     memcpy(anname, (char[]){0xc0, 0x0c}, 2);
 244
 245     struct dns_record_line *drec_data = (struct dns_record_line*)(dpkt->data+(query_states[id].namelen)+sizeof(struct dns_query_line)+2);
 246     drec_data->type = htons(12); /* AAAA */
 247     drec_data->class = htons(1); /* IN */
 248     /* FIXME: read the TTL from block:
 249      * GNUNET_TIME_absolute_get_remaining(rec->expiration_time)
 250      *
 251      * But how to get the seconds out of this?
 252      */
 253     drec_data->ttl = htonl(3600);
 254
 255     /* Calculate at which offset in the packet the length of the name and the
 256      * name, it is filled in by the daemon-vpn */
 257     answer->pkt.addroffset = htons((unsigned short)((unsigned long)(&drec_data->data_len)-(unsigned long)(&answer->pkt)));
 258
 259     GNUNET_CONTAINER_DLL_insert_after(head, tail, tail, answer);
 260
 261     GNUNET_SERVER_notify_transmit_ready(query_states[id].client,
 262                                         len,
 263                                         GNUNET_TIME_UNIT_FOREVER_REL,
 264                                         &send_answer,
 265                                         query_states[id].client);
 266
 267     /*
 268      * build
 269      * complete dns-packet with empty name in the answer
 270      * provide offsett of the name
 271      */
 272 }
 273
 274 /**
 275  * Receive a block from the dht.
 276  */
 277 static void
 278 receive_dht(void *cls,
 279             struct GNUNET_TIME_Absolute exp,
 280             const GNUNET_HashCode *key,
 281             const struct GNUNET_PeerIdentity *const *get_path,
 282             const struct GNUNET_PeerIdentity *const *put_path,
 283             enum GNUNET_BLOCK_Type type,
 284             size_t size,
 285             const void *data) {
 286
 287     unsigned short id = ((struct receive_dht_cls*)cls)->id;
 288     struct GNUNET_DHT_GetHandle* handle = ((struct receive_dht_cls*)cls)->handle;
 289     GNUNET_free(cls);
 290
 291     GNUNET_assert(type == GNUNET_BLOCK_TYPE_DNS);
 292
 293     /* If no query with this id is pending, ignore the block */
 294     if (query_states[id].valid != GNUNET_YES) return;
 295     query_states[id].valid = GNUNET_NO;
 296
 297     const struct GNUNET_DNS_Record* rec = data;
 298     GNUNET_log(GNUNET_ERROR_TYPE_DEBUG,
 299                "Got block of size %d, peer: %08x, desc: %08x\n",
 300                size,
 301                *((unsigned int*)&rec->peer),
 302                *((unsigned int*)&rec->service_descriptor));
 303
 304     size_t len = sizeof(struct answer_packet) - 1 \
 305                  + sizeof(struct dns_static) \
 306                  + query_states[id].namelen \
 307                  + sizeof(struct dns_query_line) \
 308                  + 2 /* To hold the pointer (as defined in RFC1035) to the name */ \
 309                  + sizeof(struct dns_record_line) - 1 \
 310                  + 16; /* To hold the IPv6-Address */
 311
 312     struct answer_packet_list* answer = GNUNET_malloc(len + 2*sizeof(struct answer_packet_list*));
 313     memset(answer, 0, len + 2*sizeof(struct answer_packet_list*));
 314
 315     answer->pkt.hdr.type = htons(GNUNET_MESSAGE_TYPE_LOCAL_RESPONSE_DNS);
 316     answer->pkt.hdr.size = htons(len);
 317     answer->pkt.subtype = GNUNET_DNS_ANSWER_TYPE_SERVICE;
 318
 319     GNUNET_CRYPTO_hash(&rec->peer,
 320                        sizeof(struct GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded),
 321                        &answer->pkt.service_descr.peer);
 322
 323     memcpy(&answer->pkt.service_descr.service_descriptor,
 324            &rec->service_descriptor,
 325            sizeof(GNUNET_HashCode));
 326     memcpy(&answer->pkt.service_descr.service_type,
 327            &rec->service_type,
 328            sizeof(answer->pkt.service_descr.service_type));
 329     memcpy(&answer->pkt.service_descr.ports, &rec->ports, sizeof(answer->pkt.service_descr.ports));
 330
 331     answer->pkt.from = query_states[id].remote_ip;
 332
 333     answer->pkt.to = query_states[id].local_ip;
 334     answer->pkt.dst_port = query_states[id].local_port;
 335
 336     struct dns_pkt *dpkt = (struct dns_pkt*)answer->pkt.data;
 337
 338     dpkt->s.id = id;
 339     dpkt->s.aa = 1;
 340     dpkt->s.qr = 1;
 341     dpkt->s.ra = 1;
 342     dpkt->s.qdcount = htons(1);
 343     dpkt->s.ancount = htons(1);
 344
 345     memcpy(dpkt->data, query_states[id].name, query_states[id].namelen);
 346     GNUNET_free(query_states[id].name);
 347
 348     struct dns_query_line* dque = (struct dns_query_line*)(dpkt->data+(query_states[id].namelen));
 349     dque->type = htons(28); /* AAAA */
 350     dque->class = htons(1); /* IN */
 351
 352     char* anname = (char*)(dpkt->data+(query_states[id].namelen)+sizeof(struct dns_query_line));
 353     memcpy(anname, (char[]){0xc0, 0x0c}, 2);
 354
 355     struct dns_record_line *drec_data = (struct dns_record_line*)(dpkt->data+(query_states[id].namelen)+sizeof(struct dns_query_line)+2);
 356     drec_data->type = htons(28); /* AAAA */
 357     drec_data->class = htons(1); /* IN */
 358
 359     /* FIXME: read the TTL from block:
 360      * GNUNET_TIME_absolute_get_remaining(rec->expiration_time)
 361      *
 362      * But how to get the seconds out of this?
 363      */
 364     drec_data->ttl = htonl(3600);
 365     drec_data->data_len = htons(16);
 366
 367     /* Calculate at which offset in the packet the IPv6-Address belongs, it is
 368      * filled in by the daemon-vpn */
 369     answer->pkt.addroffset = htons((unsigned short)((unsigned long)(&drec_data->data)-(unsigned long)(&answer->pkt)));
 370
 371     GNUNET_CONTAINER_DLL_insert_after(head, tail, tail, answer);
 372
 373     GNUNET_SERVER_notify_transmit_ready(query_states[id].client,
 374                                         len,
 375                                         GNUNET_TIME_UNIT_FOREVER_REL,
 376                                         &send_answer,
 377                                         query_states[id].client);
 378
 379     GNUNET_DHT_get_stop(handle);
 380 }
 381
 382 /**
 383  * This receives a GNUNET_MESSAGE_TYPE_REHIJACK and rehijacks the DNS
 384  */
 385 static void
 386 rehijack(void *cls,
 387          struct GNUNET_SERVER_Client *client,
 388          const struct GNUNET_MessageHeader *message) {
 389     unhijack(dnsoutport);
 390     GNUNET_SCHEDULER_add_delayed(GNUNET_TIME_UNIT_SECONDS, hijack, NULL);
 391
 392     GNUNET_SERVER_receive_done(client, GNUNET_OK);
 393 }
 394
 395 /**
 396  * This receives the dns-payload from the daemon-vpn and sends it on over the udp-socket
 397  */
 398 static void
 399 receive_query(void *cls,
 400               struct GNUNET_SERVER_Client *client,
 401               const struct GNUNET_MessageHeader *message) {
 402     struct query_packet* pkt = (struct query_packet*)message;
 403     struct dns_pkt* dns = (struct dns_pkt*)pkt->data;
 404     struct dns_pkt_parsed* pdns = parse_dns_packet(dns);
 405
 406     query_states[dns->s.id].valid = GNUNET_YES;
 407     query_states[dns->s.id].client = client;
 408     query_states[dns->s.id].local_ip = pkt->orig_from;
 409     query_states[dns->s.id].local_port = pkt->src_port;
 410     query_states[dns->s.id].remote_ip = pkt->orig_to;
 411     query_states[dns->s.id].namelen = strlen((char*)dns->data) + 1;
 412     query_states[dns->s.id].name = GNUNET_malloc(query_states[dns->s.id].namelen);
 413     memcpy(query_states[dns->s.id].name, dns->data, query_states[dns->s.id].namelen);
 414
 415     /* The query is for a .gnunet-address */
 416     if (pdns->queries[0]->namelen > 9 &&
 417         0 == strncmp(pdns->queries[0]->name+(pdns->queries[0]->namelen - 9), ".gnunet.", 9))
 418       {
 419         GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "Query for .gnunet!\n");
 420         GNUNET_HashCode key;
 421         GNUNET_CRYPTO_hash(pdns->queries[0]->name, pdns->queries[0]->namelen, &key);
 422
 423         GNUNET_log(GNUNET_ERROR_TYPE_DEBUG,
 424                    "Getting with key %08x, len is %d\n",
 425                    *((unsigned int*)&key),
 426                    pdns->queries[0]->namelen);
 427
 428         struct receive_dht_cls* cls = GNUNET_malloc(sizeof(struct receive_dht_cls));
 429         cls->id = dns->s.id;
 430
 431         cls->handle = GNUNET_DHT_get_start(dht,
 432                                            GNUNET_TIME_UNIT_MINUTES,
 433                                            GNUNET_BLOCK_TYPE_DNS,
 434                                            &key,
 435                                            DEFAULT_GET_REPLICATION,
 436                                            GNUNET_DHT_RO_NONE,
 437                                            NULL,
 438                                            0,
 439                                            NULL,
 440                                            0,
 441                                            receive_dht,
 442                                            cls);
 443
 444         goto outfree;
 445       }
 446
 447     GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "Query for '%s'; namelen=%d\n", pdns->queries[0]->name, pdns->queries[0]->namelen);
 448     /* The query is for a PTR of a previosly resolved virtual IP */
 449     if (htons(pdns->queries[0]->qtype) == 12 &&
 450         74 == pdns->queries[0]->namelen)
 451       {
 452         char* ipv6addr;
 453         char ipv6[16];
 454         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.";
 455         unsigned int i;
 456         unsigned long long ipv6prefix;
 457         unsigned int comparelen;
 458
 459         GNUNET_assert(GNUNET_OK == GNUNET_CONFIGURATION_get_value_string(cfg, "vpn", "IPV6ADDR", &ipv6addr));
 460         inet_pton (AF_INET6, ipv6addr, ipv6);
 461         GNUNET_free(ipv6addr);
 462
 463         GNUNET_assert(GNUNET_OK == GNUNET_CONFIGURATION_get_value_number(cfg, "vpn", "IPV6PREFIX", &ipv6prefix));
 464         GNUNET_assert(ipv6prefix < 127);
 465         ipv6prefix = (ipv6prefix + 7)/8;
 466
 467         for (i = ipv6prefix; i < 16; i++)
 468           ipv6[i] = 0;
 469
 470         for (i = 0; i < 16; i++)
 471           {
 472             unsigned char c1 = ipv6[i] >> 4;
 473             unsigned char c2 = ipv6[i] & 0xf;
 474
 475             if (c1 <= 9)
 476               ipv6rev[62-(4*i)] = c1 + '0';
 477             else
 478               ipv6rev[62-(4*i)] = c1 + 87; /* 87 is the difference between 'a' and 10 */
 479
 480             if (c2 <= 9)
 481               ipv6rev[62-((4*i)+2)] = c2 + '0';
 482             else
 483               ipv6rev[62-((4*i)+2)] = c2 + 87;
 484           }
 485         GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "My network is %s'.\n", ipv6rev);
 486         comparelen = 10 + 4*ipv6prefix;
 487         if(0 == strncmp(pdns->queries[0]->name+(pdns->queries[0]->namelen - comparelen),
 488                         ipv6rev + (74 - comparelen),
 489                         comparelen))
 490           {
 491             GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "Reverse-Query for .gnunet!\n");
 492
 493             GNUNET_SCHEDULER_add_now(send_rev_query, pdns);
 494
 495             goto out;
 496           }
 497       }
 498
 499     /* The query should be sent to the network */
 500
 501     struct sockaddr_in dest;
 502     memset(&dest, 0, sizeof dest);
 503     dest.sin_port = htons(53);
 504     dest.sin_addr.s_addr = pkt->orig_to;
 505
 506     GNUNET_NETWORK_socket_sendto(dnsout,
 507                                  dns,
 508                                  ntohs(pkt->hdr.size) - sizeof(struct query_packet) + 1,
 509                                  (struct sockaddr*) &dest,
 510                                  sizeof dest);
 511
 512 outfree:
 513     free_parsed_dns_packet(pdns);
 514     pdns = NULL;
 515 out:
 516     GNUNET_SERVER_receive_done(client, GNUNET_OK);
 517 }
 518
 519 static void read_response (void *cls,
 520                            const struct GNUNET_SCHEDULER_TaskContext *tc);
 521
 522 static void
 523 open_port ()
 524 {
 525   struct sockaddr_in addr;
 526
 527   dnsout = GNUNET_NETWORK_socket_create (AF_INET, SOCK_DGRAM, 0);
 528   if (dnsout == NULL)
 529     return;
 530   memset (&addr, 0, sizeof (struct sockaddr_in));
 531
 532   int err = GNUNET_NETWORK_socket_bind (dnsout,
 533                                         (struct sockaddr *) &addr,
 534                                         sizeof (struct sockaddr_in));
 535
 536   if (err != GNUNET_YES)
 537     {
 538       GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
 539                   "Could not bind a port, exiting\n");
 540       return;
 541     }
 542
 543   /* Read the port we bound to */
 544   socklen_t addrlen = sizeof (struct sockaddr_in);
 545   err = getsockname (GNUNET_NETWORK_get_fd (dnsout),
 546                      (struct sockaddr *) &addr, &addrlen);
 547
 548   dnsoutport = htons (addr.sin_port);
 549
 550   GNUNET_SCHEDULER_add_read_net (GNUNET_TIME_UNIT_FOREVER_REL, dnsout,
 551                                  &read_response, NULL);
 552 }
 553
 554 /**
 555  * Read a response-packet of the UDP-Socket
 556  */
 557 static void
 558 read_response (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc) {
 559     struct sockaddr_in addr;
 560     socklen_t addrlen = sizeof (addr);
 561     int r;
 562     int len;
 563
 564     if (tc->reason & GNUNET_SCHEDULER_REASON_SHUTDOWN)
 565       return;
 566
 567     memset(&addr, 0, sizeof addr);
 568
 569 #ifndef MINGW
 570     if (0 != ioctl (GNUNET_NETWORK_get_fd (dnsout),
 571                     FIONREAD, &len))
 572       {
 573         unhijack(dnsoutport);
 574         open_port();
 575         GNUNET_SCHEDULER_add_delayed(GNUNET_TIME_UNIT_SECONDS, hijack, NULL);
 576         return;
 577       }
 578 #else
 579     /* port the code above? */
 580     len = 65536;
 581 #endif
 582     {
 583       unsigned char buf[len];
 584       struct dns_pkt* dns = (struct dns_pkt*)buf;
 585
 586       r = GNUNET_NETWORK_socket_recvfrom (dnsout,
 587                                           buf,
 588                                           sizeof (buf),
 589                                           (struct sockaddr*)&addr,
 590                                           &addrlen);
 591
 592       if (r < 0)
 593         {
 594           unhijack(dnsoutport);
 595           open_port();
 596           GNUNET_SCHEDULER_add_delayed(GNUNET_TIME_UNIT_SECONDS, hijack, NULL);
 597           return;
 598         }
 599
 600       if (query_states[dns->s.id].valid == GNUNET_YES)
 601         {
 602           query_states[dns->s.id].valid = GNUNET_NO;
 603
 604           size_t len = sizeof(struct answer_packet) + r - 1; /* 1 for the unsigned char data[1]; */
 605           struct answer_packet_list* answer = GNUNET_malloc(len + 2*sizeof(struct answer_packet_list*));
 606           answer->pkt.hdr.type = htons(GNUNET_MESSAGE_TYPE_LOCAL_RESPONSE_DNS);
 607           answer->pkt.hdr.size = htons(len);
 608           answer->pkt.subtype = GNUNET_DNS_ANSWER_TYPE_IP;
 609           answer->pkt.from = addr.sin_addr.s_addr;
 610           answer->pkt.to = query_states[dns->s.id].local_ip;
 611           answer->pkt.dst_port = query_states[dns->s.id].local_port;
 612           memcpy(answer->pkt.data, buf, r);
 613
 614           GNUNET_CONTAINER_DLL_insert_after(head, tail, tail, answer);
 615
 616           GNUNET_SERVER_notify_transmit_ready(query_states[dns->s.id].client,
 617                                               len,
 618                                               GNUNET_TIME_UNIT_FOREVER_REL,
 619                                               &send_answer,
 620                                               query_states[dns->s.id].client);
 621         }
 622     }
 623     GNUNET_SCHEDULER_add_read_net(GNUNET_TIME_UNIT_FOREVER_REL,
 624                                   dnsout,
 625                                   &read_response,
 626                                   NULL);
 627 }
 628
 629
 630 /**
 631  * Task run during shutdown.
 632  *
 633  * @param cls unused
 634  * @param tc unused
 635  */
 636 static void
 637 cleanup_task (void *cls,
 638               const struct GNUNET_SCHEDULER_TaskContext *tc)
 639 {
 640   unhijack(dnsoutport);
 641   GNUNET_DHT_disconnect(dht);
 642 }
 643
 644 /**
 645  * @brief Create a port-map from udp and tcp redirects
 646  *
 647  * @param udp_redirects
 648  * @param tcp_redirects
 649  *
 650  * @return
 651  */
 652 uint64_t
 653 get_port_from_redirects (const char *udp_redirects, const char *tcp_redirects)
 654 {
 655   uint64_t ret = 0;
 656   char* cpy, *hostname, *redirect;
 657   int local_port, count = 0;
 658
 659   if (NULL != udp_redirects)
 660     {
 661       cpy = GNUNET_strdup (udp_redirects);
 662       for (redirect = strtok (cpy, " "); redirect != NULL; redirect = strtok (NULL, " "))
 663         {
 664           if (NULL == (hostname = strstr (redirect, ":")))
 665             {
 666               GNUNET_log(GNUNET_ERROR_TYPE_WARNING, "Warning: option %s is not formatted correctly!\n", redirect);
 667               continue;
 668             }
 669           hostname[0] = '\0';
 670           local_port = atoi (redirect);
 671           if (!((local_port > 0) && (local_port < 65536)))
 672             GNUNET_log(GNUNET_ERROR_TYPE_WARNING, "Warning: %s is not a correct port.", redirect);
 673
 674           ret |= (0xFFFF & htons(local_port));
 675           ret <<= 16;
 676           count ++;
 677
 678           if(count > 4)
 679             {
 680               ret = 0;
 681               goto out;
 682             }
 683         }
 684       GNUNET_free(cpy);
 685       cpy = NULL;
 686     }
 687
 688   if (NULL != tcp_redirects)
 689     {
 690       cpy = GNUNET_strdup (tcp_redirects);
 691       for (redirect = strtok (cpy, " "); redirect != NULL; redirect = strtok (NULL, " "))
 692         {
 693           if (NULL == (hostname = strstr (redirect, ":")))
 694             {
 695               GNUNET_log(GNUNET_ERROR_TYPE_WARNING, "Warning: option %s is not formatted correctly!\n", redirect);
 696               continue;
 697             }
 698           hostname[0] = '\0';
 699           local_port = atoi (redirect);
 700           if (!((local_port > 0) && (local_port < 65536)))
 701             GNUNET_log(GNUNET_ERROR_TYPE_WARNING, "Warning: %s is not a correct port.", redirect);
 702
 703           ret |= (0xFFFF & htons(local_port));
 704           ret <<= 16;
 705           count ++;
 706
 707           if(count > 4)
 708             {
 709               ret = 0;
 710               goto out;
 711             }
 712         }
 713       GNUNET_free(cpy);
 714       cpy = NULL;
 715     }
 716
 717 out:
 718   if (NULL != cpy)
 719     GNUNET_free(cpy);
 720   return ret;
 721 }
 722
 723 void
 724 publish_name (const char *name, uint64_t ports, uint32_t service_type,
 725               struct GNUNET_CRYPTO_RsaPrivateKey *my_private_key)
 726 {
 727   size_t size = sizeof (struct GNUNET_DNS_Record);
 728   struct GNUNET_DNS_Record data;
 729   memset (&data, 0, size);
 730
 731   data.purpose.size =
 732     htonl (size - sizeof (struct GNUNET_CRYPTO_RsaSignature));
 733   data.purpose.purpose = GNUNET_SIGNATURE_PURPOSE_DNS_RECORD;
 734
 735   GNUNET_CRYPTO_hash (name, strlen (name) + 1, &data.service_descriptor);
 736   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Store with key1 %x\n",
 737               *((unsigned long long *) &data.service_descriptor));
 738
 739   data.service_type = service_type;
 740   data.ports = ports;
 741
 742   GNUNET_CRYPTO_rsa_key_get_public (my_private_key, &data.peer);
 743
 744   data.expiration_time =
 745     GNUNET_TIME_relative_to_absolute (GNUNET_TIME_relative_multiply(GNUNET_TIME_UNIT_HOURS, 2));
 746
 747   /* Sign the block */
 748   if (GNUNET_OK != GNUNET_CRYPTO_rsa_sign (my_private_key,
 749                                            &data.purpose, &data.signature))
 750     {
 751       GNUNET_log (GNUNET_ERROR_TYPE_ERROR, "could not sign DNS_Record\n");
 752       return;
 753     }
 754
 755   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 756               "Putting with key %08x, size = %d\n",
 757               *((unsigned int *) &data.service_descriptor), size);
 758
 759   GNUNET_DHT_put (dht,
 760                   &data.service_descriptor,
 761                   DEFAULT_PUT_REPLICATION,
 762                   GNUNET_DHT_RO_NONE,
 763                   GNUNET_BLOCK_TYPE_DNS,
 764                   size,
 765                   (char *) &data,
 766                   GNUNET_TIME_relative_to_absolute (GNUNET_TIME_UNIT_HOURS),
 767                   GNUNET_TIME_UNIT_MINUTES, NULL, NULL);
 768 }
 769
 770 /**
 771  * @brief Publishes the record defined by the section section
 772  *
 773  * @param cls closure
 774  * @param section the current section
 775  */
 776 void
 777 publish_iterate (void *cls, const char *section)
 778 {
 779   char *udp_redirects, *tcp_redirects, *alternative_names, *alternative_name,
 780     *keyfile;
 781
 782   GNUNET_CONFIGURATION_get_value_string (servicecfg, section,
 783                                          "UDP_REDIRECTS", &udp_redirects);
 784   GNUNET_CONFIGURATION_get_value_string (servicecfg, section, "TCP_REDIRECTS",
 785                                          &tcp_redirects);
 786
 787   if (GNUNET_OK != GNUNET_CONFIGURATION_get_value_filename (cfg, "GNUNETD",
 788                                                             "HOSTKEY",
 789                                                             &keyfile))
 790     {
 791       GNUNET_log (GNUNET_ERROR_TYPE_ERROR, "could not read keyfile-value\n");
 792       if (keyfile != NULL)
 793         GNUNET_free (keyfile);
 794       return;
 795     }
 796
 797   struct GNUNET_CRYPTO_RsaPrivateKey *my_private_key =
 798     GNUNET_CRYPTO_rsa_key_create_from_file (keyfile);
 799   GNUNET_free (keyfile);
 800   GNUNET_assert (my_private_key != NULL);
 801
 802   uint64_t ports = get_port_from_redirects (udp_redirects, tcp_redirects);
 803   uint32_t service_type = 0;
 804
 805   if (NULL != udp_redirects)
 806     service_type = GNUNET_DNS_SERVICE_TYPE_UDP;
 807
 808   if (NULL != tcp_redirects)
 809     service_type |= GNUNET_DNS_SERVICE_TYPE_TCP;
 810
 811   service_type = htonl (service_type);
 812
 813
 814   publish_name (section, ports, service_type, my_private_key);
 815
 816   GNUNET_CONFIGURATION_get_value_string (servicecfg, section,
 817                                          "ALTERNATIVE_NAMES",
 818                                          &alternative_names);
 819   for (alternative_name = strtok (alternative_names, " ");
 820        alternative_name != NULL; alternative_name = strtok (NULL, " "))
 821     {
 822       char *altname =
 823         alloca (strlen (alternative_name) + strlen (section) + 1 + 1);
 824       strcpy (altname, alternative_name);
 825       strcpy (altname + strlen (alternative_name) + 1, section);
 826       altname[strlen (alternative_name)] = '.';
 827
 828       publish_name (altname, ports, service_type, my_private_key);
 829     }
 830
 831   GNUNET_free_non_null(alternative_names);
 832   GNUNET_CRYPTO_rsa_key_free (my_private_key);
 833   GNUNET_free_non_null (udp_redirects);
 834   GNUNET_free_non_null (tcp_redirects);
 835 }
 836
 837 /**
 838  * Publish a DNS-record in the DHT. This is up to now just for testing.
 839  */
 840 static void
 841 publish_names (void *cls,
 842                const struct GNUNET_SCHEDULER_TaskContext *tc) {
 843     char *services;
 844     if (0 != (tc->reason & GNUNET_SCHEDULER_REASON_SHUTDOWN))
 845       return;
 846
 847     if (NULL != servicecfg)
 848       GNUNET_CONFIGURATION_destroy(servicecfg);
 849
 850     GNUNET_CONFIGURATION_get_value_filename(cfg, "dns", "SERVICES", &services);
 851
 852     servicecfg = GNUNET_CONFIGURATION_create();
 853     if (GNUNET_OK == GNUNET_CONFIGURATION_parse(servicecfg, services))
 854       {
 855         GNUNET_log(GNUNET_ERROR_TYPE_INFO, "Parsing services %s\n", services);
 856         GNUNET_CONFIGURATION_iterate_sections(servicecfg, publish_iterate, NULL);
 857       }
 858     if (NULL != services)
 859       GNUNET_free(services);
 860
 861     GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_UNIT_HOURS,
 862                                   publish_names,
 863                                   NULL);
 864 }
 865
 866 /**
 867  * @param cls closure
 868  * @param server the initialized server
 869  * @param cfg_ configuration to use
 870  */
 871 static void
 872 run (void *cls,
 873      struct GNUNET_SERVER_Handle *server,
 874      const struct GNUNET_CONFIGURATION_Handle *cfg_)
 875 {
 876   static const struct GNUNET_SERVER_MessageHandler handlers[] = {
 877       /* callback, cls, type, size */
 878         {&receive_query, NULL, GNUNET_MESSAGE_TYPE_LOCAL_QUERY_DNS, 0},
 879         {&rehijack, NULL, GNUNET_MESSAGE_TYPE_REHIJACK, sizeof(struct GNUNET_MessageHeader)},
 880         {NULL, NULL, 0, 0}
 881   };
 882
 883   cfg = cfg_;
 884
 885   unsigned int i;
 886   for (i = 0; i < 65536; i++) {
 887       query_states[i].valid = GNUNET_NO;
 888   }
 889
 890   dht = GNUNET_DHT_connect(cfg, 1024);
 891
 892   open_port();
 893
 894   GNUNET_SCHEDULER_add_now (publish_names, NULL);
 895
 896   GNUNET_SERVER_add_handlers (server, handlers);
 897   GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_UNIT_FOREVER_REL,
 898                                 &cleanup_task,
 899                                 cls);
 900 }
 901
 902 /**
 903  * The main function for the dns service.
 904  *
 905  * @param argc number of arguments from the command line
 906  * @param argv command line arguments
 907  * @return 0 ok, 1 on error
 908  */
 909 int
 910 main (int argc, char *const *argv)
 911 {
 912   return (GNUNET_OK ==
 913           GNUNET_SERVICE_run (argc,
 914                               argv,
 915                               "dns",
 916                               GNUNET_SERVICE_OPTION_NONE,
 917                               &run, NULL)) ? 0 : 1;
 918 }