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 /**
 269  * Receive a block from the dht.
 270  */
 271 static void
 272 receive_dht(void *cls,
 273             struct GNUNET_TIME_Absolute exp,
 274             const GNUNET_HashCode *key,
 275             const struct GNUNET_PeerIdentity *const *get_path,
 276             const struct GNUNET_PeerIdentity *const *put_path,
 277             enum GNUNET_BLOCK_Type type,
 278             size_t size,
 279             const void *data) {
 280
 281     unsigned short id = ((struct receive_dht_cls*)cls)->id;
 282     struct GNUNET_DHT_GetHandle* handle = ((struct receive_dht_cls*)cls)->handle;
 283     GNUNET_free(cls);
 284
 285     GNUNET_assert(type == GNUNET_BLOCK_TYPE_DNS);
 286
 287     /* If no query with this id is pending, ignore the block */
 288     if (query_states[id].valid != GNUNET_YES) return;
 289     query_states[id].valid = GNUNET_NO;
 290
 291     const struct GNUNET_DNS_Record* rec = data;
 292     GNUNET_log(GNUNET_ERROR_TYPE_DEBUG,
 293                "Got block of size %d, peer: %08x, desc: %08x\n",
 294                size,
 295                *((unsigned int*)&rec->peer),
 296                *((unsigned int*)&rec->service_descriptor));
 297
 298     size_t len = sizeof(struct answer_packet) - 1 \
 299                  + sizeof(struct dns_static) \
 300                  + query_states[id].namelen \
 301                  + sizeof(struct dns_query_line) \
 302                  + 2 /* To hold the pointer (as defined in RFC1035) to the name */ \
 303                  + sizeof(struct dns_record_line) - 1 \
 304                  + 16; /* To hold the IPv6-Address */
 305
 306     struct answer_packet_list* answer = GNUNET_malloc(len + 2*sizeof(struct answer_packet_list*));
 307     memset(answer, 0, len + 2*sizeof(struct answer_packet_list*));
 308
 309     answer->pkt.hdr.type = htons(GNUNET_MESSAGE_TYPE_LOCAL_RESPONSE_DNS);
 310     answer->pkt.hdr.size = htons(len);
 311     answer->pkt.subtype = GNUNET_DNS_ANSWER_TYPE_SERVICE;
 312
 313     GNUNET_CRYPTO_hash(&rec->peer,
 314                        sizeof(struct GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded),
 315                        &answer->pkt.service_descr.peer);
 316
 317     memcpy(&answer->pkt.service_descr.service_descriptor,
 318            &rec->service_descriptor,
 319            sizeof(GNUNET_HashCode));
 320     memcpy(&answer->pkt.service_descr.service_type,
 321            &rec->service_type,
 322            sizeof(answer->pkt.service_descr.service_type));
 323     memcpy(&answer->pkt.service_descr.ports, &rec->ports, sizeof(answer->pkt.service_descr.ports));
 324
 325     answer->pkt.from = query_states[id].remote_ip;
 326
 327     answer->pkt.to = query_states[id].local_ip;
 328     answer->pkt.dst_port = query_states[id].local_port;
 329
 330     struct dns_pkt *dpkt = (struct dns_pkt*)answer->pkt.data;
 331
 332     dpkt->s.id = id;
 333     dpkt->s.aa = 1;
 334     dpkt->s.qr = 1;
 335     dpkt->s.ra = 1;
 336     dpkt->s.qdcount = htons(1);
 337     dpkt->s.ancount = htons(1);
 338
 339     memcpy(dpkt->data, query_states[id].name, query_states[id].namelen);
 340     GNUNET_free(query_states[id].name);
 341
 342     struct dns_query_line* dque = (struct dns_query_line*)(dpkt->data+(query_states[id].namelen));
 343     dque->type = htons(28); /* AAAA */
 344     dque->class = htons(1); /* IN */
 345
 346     char* anname = (char*)(dpkt->data+(query_states[id].namelen)+sizeof(struct dns_query_line));
 347     memcpy(anname, (char[]){0xc0, 0x0c}, 2);
 348
 349     struct dns_record_line *drec_data = (struct dns_record_line*)(dpkt->data+(query_states[id].namelen)+sizeof(struct dns_query_line)+2);
 350     drec_data->type = htons(28); /* AAAA */
 351     drec_data->class = htons(1); /* IN */
 352
 353     /* FIXME: read the TTL from block:
 354      * GNUNET_TIME_absolute_get_remaining(rec->expiration_time)
 355      *
 356      * But how to get the seconds out of this?
 357      */
 358     drec_data->ttl = htonl(3600);
 359     drec_data->data_len = htons(16);
 360
 361     /* Calculate at which offset in the packet the IPv6-Address belongs, it is
 362      * filled in by the daemon-vpn */
 363     answer->pkt.addroffset = htons((unsigned short)((unsigned long)(&drec_data->data)-(unsigned long)(&answer->pkt)));
 364
 365     GNUNET_CONTAINER_DLL_insert_after(head, tail, tail, answer);
 366
 367     GNUNET_SERVER_notify_transmit_ready(query_states[id].client,
 368                                         len,
 369                                         GNUNET_TIME_UNIT_FOREVER_REL,
 370                                         &send_answer,
 371                                         query_states[id].client);
 372
 373     GNUNET_DHT_get_stop(handle);
 374 }
 375
 376 /**
 377  * This receives a GNUNET_MESSAGE_TYPE_REHIJACK and rehijacks the DNS
 378  */
 379 static void
 380 rehijack(void *cls,
 381          struct GNUNET_SERVER_Client *client,
 382          const struct GNUNET_MessageHeader *message) {
 383     unhijack(dnsoutport);
 384     GNUNET_SCHEDULER_add_delayed(GNUNET_TIME_UNIT_SECONDS, hijack, NULL);
 385
 386     GNUNET_SERVER_receive_done(client, GNUNET_OK);
 387 }
 388
 389 /**
 390  * This receives the dns-payload from the daemon-vpn and sends it on over the udp-socket
 391  */
 392 static void
 393 receive_query(void *cls,
 394               struct GNUNET_SERVER_Client *client,
 395               const struct GNUNET_MessageHeader *message) {
 396     struct query_packet* pkt = (struct query_packet*)message;
 397     struct dns_pkt* dns = (struct dns_pkt*)pkt->data;
 398     struct dns_pkt_parsed* pdns = parse_dns_packet(dns);
 399
 400     query_states[dns->s.id].valid = GNUNET_YES;
 401     query_states[dns->s.id].client = client;
 402     query_states[dns->s.id].local_ip = pkt->orig_from;
 403     query_states[dns->s.id].local_port = pkt->src_port;
 404     query_states[dns->s.id].remote_ip = pkt->orig_to;
 405     query_states[dns->s.id].namelen = strlen((char*)dns->data) + 1;
 406     query_states[dns->s.id].name = GNUNET_malloc(query_states[dns->s.id].namelen);
 407     memcpy(query_states[dns->s.id].name, dns->data, query_states[dns->s.id].namelen);
 408
 409     /* The query is for a .gnunet-address */
 410     if (pdns->queries[0]->namelen > 9 &&
 411         0 == strncmp(pdns->queries[0]->name+(pdns->queries[0]->namelen - 9), ".gnunet.", 9))
 412       {
 413         GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "Query for .gnunet!\n");
 414         GNUNET_HashCode key;
 415         GNUNET_CRYPTO_hash(pdns->queries[0]->name, pdns->queries[0]->namelen, &key);
 416
 417         GNUNET_log(GNUNET_ERROR_TYPE_DEBUG,
 418                    "Getting with key %08x, len is %d\n",
 419                    *((unsigned int*)&key),
 420                    pdns->queries[0]->namelen);
 421
 422         struct receive_dht_cls* cls = GNUNET_malloc(sizeof(struct receive_dht_cls));
 423         cls->id = dns->s.id;
 424
 425         cls->handle = GNUNET_DHT_get_start(dht,
 426                                            GNUNET_TIME_UNIT_MINUTES,
 427                                            GNUNET_BLOCK_TYPE_DNS,
 428                                            &key,
 429                                            DEFAULT_GET_REPLICATION,
 430                                            GNUNET_DHT_RO_NONE,
 431                                            NULL,
 432                                            0,
 433                                            NULL,
 434                                            0,
 435                                            receive_dht,
 436                                            cls);
 437
 438         goto outfree;
 439       }
 440
 441     GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "Query for '%s'; namelen=%d\n", pdns->queries[0]->name, pdns->queries[0]->namelen);
 442     /* The query is for a PTR of a previosly resolved virtual IP */
 443     if (htons(pdns->queries[0]->qtype) == 12 &&
 444         74 == pdns->queries[0]->namelen)
 445       {
 446         char* ipv6addr;
 447         char ipv6[16];
 448         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.";
 449         unsigned int i;
 450         unsigned long long ipv6prefix;
 451         unsigned int comparelen;
 452
 453         GNUNET_assert(GNUNET_OK == GNUNET_CONFIGURATION_get_value_string(cfg, "vpn", "IPV6ADDR", &ipv6addr));
 454         inet_pton (AF_INET6, ipv6addr, ipv6);
 455         GNUNET_free(ipv6addr);
 456
 457         GNUNET_assert(GNUNET_OK == GNUNET_CONFIGURATION_get_value_number(cfg, "vpn", "IPV6PREFIX", &ipv6prefix));
 458         GNUNET_assert(ipv6prefix < 127);
 459         ipv6prefix = (ipv6prefix + 7)/8;
 460
 461         for (i = ipv6prefix; i < 16; i++)
 462           ipv6[i] = 0;
 463
 464         for (i = 0; i < 16; i++)
 465           {
 466             unsigned char c1 = ipv6[i] >> 4;
 467             unsigned char c2 = ipv6[i] & 0xf;
 468
 469             if (c1 <= 9)
 470               ipv6rev[62-(4*i)] = c1 + '0';
 471             else
 472               ipv6rev[62-(4*i)] = c1 + 87; /* 87 is the difference between 'a' and 10 */
 473
 474             if (c2 <= 9)
 475               ipv6rev[62-((4*i)+2)] = c2 + '0';
 476             else
 477               ipv6rev[62-((4*i)+2)] = c2 + 87;
 478           }
 479         GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "My network is %s'.\n", ipv6rev);
 480         comparelen = 10 + 4*ipv6prefix;
 481         if(0 == strncmp(pdns->queries[0]->name+(pdns->queries[0]->namelen - comparelen),
 482                         ipv6rev + (74 - comparelen),
 483                         comparelen))
 484           {
 485             GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "Reverse-Query for .gnunet!\n");
 486
 487             GNUNET_SCHEDULER_add_now(send_rev_query, pdns);
 488
 489             goto out;
 490           }
 491       }
 492
 493     /* The query should be sent to the network */
 494
 495     struct sockaddr_in dest;
 496     memset(&dest, 0, sizeof dest);
 497     dest.sin_port = htons(53);
 498     dest.sin_addr.s_addr = pkt->orig_to;
 499
 500     GNUNET_NETWORK_socket_sendto(dnsout,
 501                                  dns,
 502                                  ntohs(pkt->hdr.size) - sizeof(struct query_packet) + 1,
 503                                  (struct sockaddr*) &dest,
 504                                  sizeof dest);
 505
 506 outfree:
 507     free_parsed_dns_packet(pdns);
 508     pdns = NULL;
 509 out:
 510     GNUNET_SERVER_receive_done(client, GNUNET_OK);
 511 }
 512
 513 static void read_response (void *cls,
 514                            const struct GNUNET_SCHEDULER_TaskContext *tc);
 515
 516 static void
 517 open_port ()
 518 {
 519   struct sockaddr_in addr;
 520
 521   dnsout = GNUNET_NETWORK_socket_create (AF_INET, SOCK_DGRAM, 0);
 522   if (dnsout == NULL)
 523     return;
 524   memset (&addr, 0, sizeof (struct sockaddr_in));
 525
 526   int err = GNUNET_NETWORK_socket_bind (dnsout,
 527                                         (struct sockaddr *) &addr,
 528                                         sizeof (struct sockaddr_in));
 529
 530   if (err != GNUNET_YES)
 531     {
 532       GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
 533                   "Could not bind a port, exiting\n");
 534       return;
 535     }
 536
 537   /* Read the port we bound to */
 538   socklen_t addrlen = sizeof (struct sockaddr_in);
 539   err = getsockname (GNUNET_NETWORK_get_fd (dnsout),
 540                      (struct sockaddr *) &addr, &addrlen);
 541
 542   dnsoutport = htons (addr.sin_port);
 543
 544   GNUNET_SCHEDULER_add_read_net (GNUNET_TIME_UNIT_FOREVER_REL, dnsout,
 545                                  &read_response, NULL);
 546 }
 547
 548 /**
 549  * Read a response-packet of the UDP-Socket
 550  */
 551 static void
 552 read_response (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc) {
 553     struct sockaddr_in addr;
 554     socklen_t addrlen = sizeof (addr);
 555     int r;
 556     int len;
 557
 558     if (tc->reason & GNUNET_SCHEDULER_REASON_SHUTDOWN)
 559       return;
 560
 561     memset(&addr, 0, sizeof addr);
 562
 563 #ifndef MINGW
 564     if (0 != ioctl (GNUNET_NETWORK_get_fd (dnsout),
 565                     FIONREAD, &len))
 566       {
 567         unhijack(dnsoutport);
 568         open_port();
 569         GNUNET_SCHEDULER_add_delayed(GNUNET_TIME_UNIT_SECONDS, hijack, NULL);
 570         return;
 571       }
 572 #else
 573     /* port the code above? */
 574     len = 65536;
 575 #endif
 576     {
 577       unsigned char buf[len];
 578       struct dns_pkt* dns = (struct dns_pkt*)buf;
 579
 580       r = GNUNET_NETWORK_socket_recvfrom (dnsout,
 581                                           buf,
 582                                           sizeof (buf),
 583                                           (struct sockaddr*)&addr,
 584                                           &addrlen);
 585
 586       if (r < 0)
 587         {
 588           unhijack(dnsoutport);
 589           open_port();
 590           GNUNET_SCHEDULER_add_delayed(GNUNET_TIME_UNIT_SECONDS, hijack, NULL);
 591           return;
 592         }
 593
 594       if (query_states[dns->s.id].valid == GNUNET_YES)
 595         {
 596           query_states[dns->s.id].valid = GNUNET_NO;
 597
 598           size_t len = sizeof(struct answer_packet) + r - 1; /* 1 for the unsigned char data[1]; */
 599           struct answer_packet_list* answer = GNUNET_malloc(len + 2*sizeof(struct answer_packet_list*));
 600           answer->pkt.hdr.type = htons(GNUNET_MESSAGE_TYPE_LOCAL_RESPONSE_DNS);
 601           answer->pkt.hdr.size = htons(len);
 602           answer->pkt.subtype = GNUNET_DNS_ANSWER_TYPE_IP;
 603           answer->pkt.from = addr.sin_addr.s_addr;
 604           answer->pkt.to = query_states[dns->s.id].local_ip;
 605           answer->pkt.dst_port = query_states[dns->s.id].local_port;
 606           memcpy(answer->pkt.data, buf, r);
 607
 608           GNUNET_CONTAINER_DLL_insert_after(head, tail, tail, answer);
 609
 610           GNUNET_SERVER_notify_transmit_ready(query_states[dns->s.id].client,
 611                                               len,
 612                                               GNUNET_TIME_UNIT_FOREVER_REL,
 613                                               &send_answer,
 614                                               query_states[dns->s.id].client);
 615         }
 616     }
 617     GNUNET_SCHEDULER_add_read_net(GNUNET_TIME_UNIT_FOREVER_REL,
 618                                   dnsout,
 619                                   &read_response,
 620                                   NULL);
 621 }
 622
 623
 624 /**
 625  * Task run during shutdown.
 626  *
 627  * @param cls unused
 628  * @param tc unused
 629  */
 630 static void
 631 cleanup_task (void *cls,
 632               const struct GNUNET_SCHEDULER_TaskContext *tc)
 633 {
 634   unhijack(dnsoutport);
 635   GNUNET_DHT_disconnect(dht);
 636 }
 637
 638 /**
 639  * @brief Create a port-map from udp and tcp redirects
 640  *
 641  * @param udp_redirects
 642  * @param tcp_redirects
 643  *
 644  * @return
 645  */
 646 uint64_t
 647 get_port_from_redirects (const char *udp_redirects, const char *tcp_redirects)
 648 {
 649   uint64_t ret = 0;
 650   char* cpy, *hostname, *redirect;
 651   int local_port, count = 0;
 652
 653   if (NULL != udp_redirects)
 654     {
 655       cpy = GNUNET_strdup (udp_redirects);
 656       for (redirect = strtok (cpy, " "); redirect != NULL; redirect = strtok (NULL, " "))
 657         {
 658           if (NULL == (hostname = strstr (redirect, ":")))
 659             {
 660               GNUNET_log(GNUNET_ERROR_TYPE_WARNING, "Warning: option %s is not formatted correctly!\n", redirect);
 661               continue;
 662             }
 663           hostname[0] = '\0';
 664           local_port = atoi (redirect);
 665           if (!((local_port > 0) && (local_port < 65536)))
 666             GNUNET_log(GNUNET_ERROR_TYPE_WARNING, "Warning: %s is not a correct port.", redirect);
 667
 668           ret |= (0xFFFF & htons(local_port));
 669           ret <<= 16;
 670           count ++;
 671
 672           if(count > 4)
 673             {
 674               ret = 0;
 675               goto out;
 676             }
 677         }
 678       GNUNET_free(cpy);
 679       cpy = NULL;
 680     }
 681
 682   if (NULL != tcp_redirects)
 683     {
 684       cpy = GNUNET_strdup (tcp_redirects);
 685       for (redirect = strtok (cpy, " "); redirect != NULL; redirect = strtok (NULL, " "))
 686         {
 687           if (NULL == (hostname = strstr (redirect, ":")))
 688             {
 689               GNUNET_log(GNUNET_ERROR_TYPE_WARNING, "Warning: option %s is not formatted correctly!\n", redirect);
 690               continue;
 691             }
 692           hostname[0] = '\0';
 693           local_port = atoi (redirect);
 694           if (!((local_port > 0) && (local_port < 65536)))
 695             GNUNET_log(GNUNET_ERROR_TYPE_WARNING, "Warning: %s is not a correct port.", redirect);
 696
 697           ret |= (0xFFFF & htons(local_port));
 698           ret <<= 16;
 699           count ++;
 700
 701           if(count > 4)
 702             {
 703               ret = 0;
 704               goto out;
 705             }
 706         }
 707       GNUNET_free(cpy);
 708       cpy = NULL;
 709     }
 710
 711 out:
 712   if (NULL != cpy)
 713     GNUNET_free(cpy);
 714   return ret;
 715 }
 716
 717 void
 718 publish_name (const char *name, uint64_t ports, uint32_t service_type,
 719               struct GNUNET_CRYPTO_RsaPrivateKey *my_private_key)
 720 {
 721   size_t size = sizeof (struct GNUNET_DNS_Record);
 722   struct GNUNET_DNS_Record data;
 723   memset (&data, 0, size);
 724
 725   data.purpose.size =
 726     htonl (size - sizeof (struct GNUNET_CRYPTO_RsaSignature));
 727   data.purpose.purpose = GNUNET_SIGNATURE_PURPOSE_DNS_RECORD;
 728
 729   GNUNET_CRYPTO_hash (name, strlen (name) + 1, &data.service_descriptor);
 730   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Store with key1 %x\n",
 731               *((unsigned long long *) &data.service_descriptor));
 732
 733   data.service_type = service_type;
 734   data.ports = ports;
 735
 736   GNUNET_CRYPTO_rsa_key_get_public (my_private_key, &data.peer);
 737
 738   data.expiration_time =
 739     GNUNET_TIME_relative_to_absolute (GNUNET_TIME_relative_multiply(GNUNET_TIME_UNIT_HOURS, 2));
 740
 741   /* Sign the block */
 742   if (GNUNET_OK != GNUNET_CRYPTO_rsa_sign (my_private_key,
 743                                            &data.purpose, &data.signature))
 744     {
 745       GNUNET_log (GNUNET_ERROR_TYPE_ERROR, "could not sign DNS_Record\n");
 746       return;
 747     }
 748
 749   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 750               "Putting with key %08x, size = %d\n",
 751               *((unsigned int *) &data.service_descriptor), size);
 752
 753   GNUNET_DHT_put (dht,
 754                   &data.service_descriptor,
 755                   DEFAULT_PUT_REPLICATION,
 756                   GNUNET_DHT_RO_NONE,
 757                   GNUNET_BLOCK_TYPE_DNS,
 758                   size,
 759                   (char *) &data,
 760                   GNUNET_TIME_relative_to_absolute (GNUNET_TIME_UNIT_HOURS),
 761                   GNUNET_TIME_UNIT_MINUTES, NULL, NULL);
 762 }
 763
 764 /**
 765  * @brief Publishes the record defined by the section section
 766  *
 767  * @param cls closure
 768  * @param section the current section
 769  */
 770 void
 771 publish_iterate (void *cls, const char *section)
 772 {
 773   char *udp_redirects, *tcp_redirects, *alternative_names, *alternative_name,
 774     *keyfile;
 775
 776   GNUNET_CONFIGURATION_get_value_string (servicecfg, section,
 777                                          "UDP_REDIRECTS", &udp_redirects);
 778   GNUNET_CONFIGURATION_get_value_string (servicecfg, section, "TCP_REDIRECTS",
 779                                          &tcp_redirects);
 780
 781   if (GNUNET_OK != GNUNET_CONFIGURATION_get_value_filename (cfg, "GNUNETD",
 782                                                             "HOSTKEY",
 783                                                             &keyfile))
 784     {
 785       GNUNET_log (GNUNET_ERROR_TYPE_ERROR, "could not read keyfile-value\n");
 786       if (keyfile != NULL)
 787         GNUNET_free (keyfile);
 788       return;
 789     }
 790
 791   struct GNUNET_CRYPTO_RsaPrivateKey *my_private_key =
 792     GNUNET_CRYPTO_rsa_key_create_from_file (keyfile);
 793   GNUNET_free (keyfile);
 794   GNUNET_assert (my_private_key != NULL);
 795
 796   uint64_t ports = get_port_from_redirects (udp_redirects, tcp_redirects);
 797   uint32_t service_type = 0;
 798
 799   if (NULL != udp_redirects)
 800     service_type = GNUNET_DNS_SERVICE_TYPE_UDP;
 801
 802   if (NULL != tcp_redirects)
 803     service_type |= GNUNET_DNS_SERVICE_TYPE_TCP;
 804
 805   service_type = htonl (service_type);
 806
 807
 808   publish_name (section, ports, service_type, my_private_key);
 809
 810   GNUNET_CONFIGURATION_get_value_string (servicecfg, section,
 811                                          "ALTERNATIVE_NAMES",
 812                                          &alternative_names);
 813   for (alternative_name = strtok (alternative_names, " ");
 814        alternative_name != NULL; alternative_name = strtok (NULL, " "))
 815     {
 816       char *altname =
 817         alloca (strlen (alternative_name) + strlen (section) + 1 + 1);
 818       strcpy (altname, alternative_name);
 819       strcpy (altname + strlen (alternative_name) + 1, section);
 820       altname[strlen (alternative_name)] = '.';
 821
 822       publish_name (altname, ports, service_type, my_private_key);
 823     }
 824
 825   GNUNET_free_non_null(alternative_names);
 826   GNUNET_CRYPTO_rsa_key_free (my_private_key);
 827   GNUNET_free_non_null (udp_redirects);
 828   GNUNET_free_non_null (tcp_redirects);
 829 }
 830
 831 /**
 832  * Publish a DNS-record in the DHT. This is up to now just for testing.
 833  */
 834 static void
 835 publish_names (void *cls,
 836                const struct GNUNET_SCHEDULER_TaskContext *tc) {
 837     char *services;
 838     if (0 != (tc->reason & GNUNET_SCHEDULER_REASON_SHUTDOWN))
 839       return;
 840
 841     if (NULL != servicecfg)
 842       GNUNET_CONFIGURATION_destroy(servicecfg);
 843
 844     GNUNET_CONFIGURATION_get_value_filename(cfg, "dns", "SERVICES", &services);
 845
 846     servicecfg = GNUNET_CONFIGURATION_create();
 847     if (GNUNET_OK == GNUNET_CONFIGURATION_parse(servicecfg, services))
 848       {
 849         GNUNET_log(GNUNET_ERROR_TYPE_INFO, "Parsing services %s\n", services);
 850         GNUNET_CONFIGURATION_iterate_sections(servicecfg, publish_iterate, NULL);
 851       }
 852     if (NULL != services)
 853       GNUNET_free(services);
 854
 855     GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_UNIT_HOURS,
 856                                   publish_names,
 857                                   NULL);
 858 }
 859
 860 /**
 861  * @param cls closure
 862  * @param server the initialized server
 863  * @param cfg_ configuration to use
 864  */
 865 static void
 866 run (void *cls,
 867      struct GNUNET_SERVER_Handle *server,
 868      const struct GNUNET_CONFIGURATION_Handle *cfg_)
 869 {
 870   static const struct GNUNET_SERVER_MessageHandler handlers[] = {
 871       /* callback, cls, type, size */
 872         {&receive_query, NULL, GNUNET_MESSAGE_TYPE_LOCAL_QUERY_DNS, 0},
 873         {&rehijack, NULL, GNUNET_MESSAGE_TYPE_REHIJACK, sizeof(struct GNUNET_MessageHeader)},
 874         {NULL, NULL, 0, 0}
 875   };
 876
 877   cfg = cfg_;
 878
 879   unsigned int i;
 880   for (i = 0; i < 65536; i++) {
 881       query_states[i].valid = GNUNET_NO;
 882   }
 883
 884   dht = GNUNET_DHT_connect(cfg, 1024);
 885
 886   open_port();
 887
 888   GNUNET_SCHEDULER_add_now (publish_names, NULL);
 889
 890   GNUNET_SERVER_add_handlers (server, handlers);
 891   GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_UNIT_FOREVER_REL,
 892                                 &cleanup_task,
 893                                 cls);
 894 }
 895
 896 /**
 897  * The main function for the dns service.
 898  *
 899  * @param argc number of arguments from the command line
 900  * @param argv command line arguments
 901  * @return 0 ok, 1 on error
 902  */
 903 int
 904 main (int argc, char *const *argv)
 905 {
 906   return (GNUNET_OK ==
 907           GNUNET_SERVICE_run (argc,
 908                               argv,
 909                               "dns",
 910                               GNUNET_SERVICE_OPTION_NONE,
 911                               &run, NULL)) ? 0 : 1;
 912 }