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-vpn-pretty-print.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_signatures.h"
  41
  42 /**
  43  * The UDP-Socket through which DNS-Resolves will be sent if they are not to be
  44  * sent through gnunet. The port of this socket will not be hijacked.
  45  */
  46 static struct GNUNET_NETWORK_Handle *dnsout;
  47
  48 /**
  49  * The port bound to the socket dnsout
  50  */
  51 static unsigned short dnsoutport;
  52
  53 /**
  54  * A handle to the DHT-Service
  55  */
  56 static struct GNUNET_DHT_Handle *dht;
  57
  58 /**
  59  * The configuration to use
  60  */
  61 static const struct GNUNET_CONFIGURATION_Handle *cfg;
  62
  63 /**
  64  * A list of DNS-Responses that have to be sent to the requesting client
  65  */
  66 static struct answer_packet_list *head;
  67
  68 /**
  69  * The tail of the list of DNS-responses
  70  */
  71 static struct answer_packet_list *tail;
  72
  73 /**
  74  * A structure containing a mapping from network-byte-ordered DNS-id to
  75  * some information needed to handle this query
  76  *
  77  * It currently allocates at least
  78  * (1 + machine-width + 32 + 32 + 16 + machine-width + 8) * 65536 bit
  79  * = 1.7 MiB on 64 bit.
  80  * = 1.2 MiB on 32 bit.
  81  */
  82 static struct {
  83     unsigned valid:1;
  84     struct GNUNET_SERVER_Client* client;
  85     unsigned local_ip:32;
  86     unsigned remote_ip:32;
  87     unsigned local_port:16;
  88     char* name;
  89     unsigned namelen:8;
  90 } query_states[65536];
  91
  92 /**
  93  * A struct used to give more than one value as
  94  * closure to receive_dht
  95  */
  96 struct receive_dht_cls {
  97     unsigned short id;
  98     struct GNUNET_DHT_GetHandle* handle;
  99 };
 100
 101 /**
 102  * Hijack all outgoing DNS-Traffic but for traffic leaving "our" port.
 103  */
 104 static void
 105 hijack(void* cls, const struct GNUNET_SCHEDULER_TaskContext* tc) {
 106     char port_s[6];
 107     char* virt_dns;
 108
 109     if (GNUNET_SYSERR == GNUNET_CONFIGURATION_get_value_string(cfg, "vpn", "VIRTDNS", &virt_dns))
 110       {
 111         GNUNET_log(GNUNET_ERROR_TYPE_ERROR, "No entry 'VIRTDNS' in configuration!\n");
 112         exit(1);
 113       }
 114
 115     GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "Hijacking, port is %d\n", dnsoutport);
 116     snprintf(port_s, 6, "%d", dnsoutport);
 117     GNUNET_OS_process_close (GNUNET_OS_start_process(NULL,
 118                                                      NULL,
 119                                                      "gnunet-helper-hijack-dns",
 120                                                      "gnunet-hijack-dns",
 121                                                      port_s,
 122                                                      virt_dns,
 123                                                      NULL));
 124 }
 125
 126 /**
 127  * Delete the hijacking-routes
 128  */
 129 static void
 130 unhijack(unsigned short port) {
 131     char port_s[6];
 132     char* virt_dns;
 133
 134     if (GNUNET_SYSERR == GNUNET_CONFIGURATION_get_value_string(cfg, "vpn", "VIRTDNS", &virt_dns))
 135       {
 136         GNUNET_log(GNUNET_ERROR_TYPE_ERROR, "No entry 'VIRTDNS' in configuration!\n");
 137         exit(1);
 138       }
 139
 140     GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "unHijacking, port is %d\n", port);
 141     snprintf(port_s, 6, "%d", port);
 142     GNUNET_OS_start_process(NULL,
 143                             NULL,
 144                             "gnunet-helper-hijack-dns",
 145                             "gnunet-hijack-dns",
 146                             "-d",
 147                             port_s,
 148                             virt_dns,
 149                             NULL);
 150 }
 151
 152 /**
 153  * Send the DNS-Response to the client. Gets called via the notify_transmit_ready-
 154  * system.
 155  */
 156 static size_t
 157 send_answer(void* cls, size_t size, void* buf) {
 158     struct answer_packet_list* query = head;
 159     size_t len = ntohs(query->pkt.hdr.size);
 160
 161     GNUNET_assert(len <= size);
 162
 163     memcpy(buf, &query->pkt.hdr, len);
 164
 165     GNUNET_CONTAINER_DLL_remove (head, tail, query);
 166
 167     GNUNET_free(query);
 168
 169     /* When more data is to be sent, reschedule */
 170     if (head != NULL)
 171       GNUNET_SERVER_notify_transmit_ready(cls,
 172                                           ntohs(head->pkt.hdr.size),
 173                                           GNUNET_TIME_UNIT_FOREVER_REL,
 174                                           &send_answer,
 175                                           cls);
 176
 177     return len;
 178 }
 179
 180 static void
 181 send_rev_query(void * cls, const struct GNUNET_SCHEDULER_TaskContext *tc) {
 182     struct dns_pkt_parsed* pdns = (struct dns_pkt_parsed*) cls;
 183
 184     unsigned short id = pdns->s.id;
 185
 186     if (query_states[id].valid != GNUNET_YES) return;
 187     query_states[id].valid = GNUNET_NO;
 188
 189     GNUNET_assert(query_states[id].namelen == 74);
 190
 191     size_t len = sizeof(struct answer_packet) - 1 \
 192                  + sizeof(struct dns_static) \
 193                  + 74 /* this is the length of a reverse ipv6-lookup */ \
 194                  + sizeof(struct dns_query_line) \
 195                  + 2 /* To hold the pointer (as defined in RFC1035) to the name */ \
 196                  + sizeof(struct dns_record_line) - 1 \
 197                  - 2 /* We do not know the lenght of the answer yet*/ \
 198                  - 2 /* No idea why... */ ;
 199
 200     struct answer_packet_list* answer = GNUNET_malloc(len + 2*sizeof(struct answer_packet_list*));
 201     memset(answer, 0, len + 2*sizeof(struct answer_packet_list*));
 202
 203     answer->pkt.hdr.type = htons(GNUNET_MESSAGE_TYPE_LOCAL_RESPONSE_DNS);
 204     answer->pkt.hdr.size = htons(len);
 205     answer->pkt.subtype = GNUNET_DNS_ANSWER_TYPE_REV;
 206
 207     answer->pkt.from = query_states[id].remote_ip;
 208
 209     answer->pkt.to = query_states[id].local_ip;
 210     answer->pkt.dst_port = query_states[id].local_port;
 211
 212     struct dns_pkt *dpkt = (struct dns_pkt*)answer->pkt.data;
 213
 214     dpkt->s.id = id;
 215     dpkt->s.aa = 1;
 216     dpkt->s.qr = 1;
 217     dpkt->s.ra = 1;
 218     dpkt->s.qdcount = htons(1);
 219     dpkt->s.ancount = htons(1);
 220
 221     memcpy(dpkt->data, query_states[id].name, query_states[id].namelen);
 222     GNUNET_free(query_states[id].name);
 223
 224     struct dns_query_line* dque = (struct dns_query_line*)(dpkt->data+(query_states[id].namelen));
 225     dque->type = htons(12); /* PTR */
 226     dque->class = htons(1); /* IN */
 227
 228     char* anname = (char*)(dpkt->data+(query_states[id].namelen)+sizeof(struct dns_query_line));
 229     memcpy(anname, (char[]){0xc0, 0x0c}, 2);
 230
 231     struct dns_record_line *drec_data = (struct dns_record_line*)(dpkt->data+(query_states[id].namelen)+sizeof(struct dns_query_line)+2);
 232     drec_data->type = htons(12); /* AAAA */
 233     drec_data->class = htons(1); /* IN */
 234     drec_data->ttl = htonl(3600); /* FIXME: read from block */
 235
 236     /* Calculate at which offset in the packet the length of the name and the
 237      * name, it is filled in by the daemon-vpn */
 238     answer->pkt.addroffset = htons((unsigned short)((unsigned long)(&drec_data->data_len)-(unsigned long)(&answer->pkt)));
 239
 240     GNUNET_CONTAINER_DLL_insert_after(head, tail, tail, answer);
 241
 242     GNUNET_SERVER_notify_transmit_ready(query_states[id].client,
 243                                         len,
 244                                         GNUNET_TIME_UNIT_FOREVER_REL,
 245                                         &send_answer,
 246                                         query_states[id].client);
 247
 248     /*
 249      * build
 250      * complete dns-packet with empty name in the answer
 251      * provide offsett of the name
 252      */
 253 }
 254
 255 /**
 256  * Receive a block from the dht.
 257  */
 258 static void
 259 receive_dht(void *cls,
 260             struct GNUNET_TIME_Absolute exp,
 261             const GNUNET_HashCode *key,
 262             const struct GNUNET_PeerIdentity *const *get_path,
 263             const struct GNUNET_PeerIdentity *const *put_path,
 264             enum GNUNET_BLOCK_Type type,
 265             size_t size,
 266             const void *data) {
 267
 268     unsigned short id = ((struct receive_dht_cls*)cls)->id;
 269     struct GNUNET_DHT_GetHandle* handle = ((struct receive_dht_cls*)cls)->handle;
 270     GNUNET_free(cls);
 271
 272     GNUNET_assert(type == GNUNET_BLOCK_TYPE_DNS);
 273
 274     /* If no query with this id is pending, ignore the block */
 275     if (query_states[id].valid != GNUNET_YES) return;
 276     query_states[id].valid = GNUNET_NO;
 277
 278     const struct GNUNET_DNS_Record* rec = data;
 279     GNUNET_log(GNUNET_ERROR_TYPE_DEBUG,
 280                "Got block of size %d, peer: %08x, desc: %08x\n",
 281                size,
 282                *((unsigned int*)&rec->peer),
 283                *((unsigned int*)&rec->service_descriptor));
 284
 285     size_t len = sizeof(struct answer_packet) - 1 \
 286                  + sizeof(struct dns_static) \
 287                  + query_states[id].namelen \
 288                  + sizeof(struct dns_query_line) \
 289                  + 2 /* To hold the pointer (as defined in RFC1035) to the name */ \
 290                  + sizeof(struct dns_record_line) - 1 \
 291                  + 16; /* To hold the IPv6-Address */
 292
 293     struct answer_packet_list* answer = GNUNET_malloc(len + 2*sizeof(struct answer_packet_list*));
 294     memset(answer, 0, len + 2*sizeof(struct answer_packet_list*));
 295
 296     answer->pkt.hdr.type = htons(GNUNET_MESSAGE_TYPE_LOCAL_RESPONSE_DNS);
 297     answer->pkt.hdr.size = htons(len);
 298     answer->pkt.subtype = GNUNET_DNS_ANSWER_TYPE_SERVICE;
 299
 300     GNUNET_CRYPTO_hash(&rec->peer,
 301                        sizeof(struct GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded),
 302                        &answer->pkt.service_descr.peer);
 303
 304     memcpy(&answer->pkt.service_descr.service_descriptor,
 305            &rec->service_descriptor,
 306            sizeof(GNUNET_HashCode));
 307     memcpy(&answer->pkt.service_descr.service_type,
 308            &rec->service_type,
 309            sizeof(answer->pkt.service_descr.service_type));
 310     memcpy(&answer->pkt.service_descr.ports, &rec->ports, sizeof(answer->pkt.service_descr.ports));
 311
 312     answer->pkt.from = query_states[id].remote_ip;
 313
 314     answer->pkt.to = query_states[id].local_ip;
 315     answer->pkt.dst_port = query_states[id].local_port;
 316
 317     struct dns_pkt *dpkt = (struct dns_pkt*)answer->pkt.data;
 318
 319     dpkt->s.id = id;
 320     dpkt->s.aa = 1;
 321     dpkt->s.qr = 1;
 322     dpkt->s.ra = 1;
 323     dpkt->s.qdcount = htons(1);
 324     dpkt->s.ancount = htons(1);
 325
 326     memcpy(dpkt->data, query_states[id].name, query_states[id].namelen);
 327     GNUNET_free(query_states[id].name);
 328
 329     struct dns_query_line* dque = (struct dns_query_line*)(dpkt->data+(query_states[id].namelen));
 330     dque->type = htons(28); /* AAAA */
 331     dque->class = htons(1); /* IN */
 332
 333     char* anname = (char*)(dpkt->data+(query_states[id].namelen)+sizeof(struct dns_query_line));
 334     memcpy(anname, (char[]){0xc0, 0x0c}, 2);
 335
 336     struct dns_record_line *drec_data = (struct dns_record_line*)(dpkt->data+(query_states[id].namelen)+sizeof(struct dns_query_line)+2);
 337     drec_data->type = htons(28); /* AAAA */
 338     drec_data->class = htons(1); /* IN */
 339     drec_data->ttl = htonl(3600); /* FIXME: read from block */
 340     drec_data->data_len = htons(16);
 341
 342     /* Calculate at which offset in the packet the IPv6-Address belongs, it is
 343      * filled in by the daemon-vpn */
 344     answer->pkt.addroffset = htons((unsigned short)((unsigned long)(&drec_data->data)-(unsigned long)(&answer->pkt)));
 345
 346     GNUNET_CONTAINER_DLL_insert_after(head, tail, tail, answer);
 347
 348     GNUNET_SERVER_notify_transmit_ready(query_states[id].client,
 349                                         len,
 350                                         GNUNET_TIME_UNIT_FOREVER_REL,
 351                                         &send_answer,
 352                                         query_states[id].client);
 353
 354     GNUNET_DHT_get_stop(handle);
 355 }
 356
 357 /**
 358  * This receives a GNUNET_MESSAGE_TYPE_REHIJACK and rehijacks the DNS
 359  */
 360 static void
 361 rehijack(void *cls,
 362          struct GNUNET_SERVER_Client *client,
 363          const struct GNUNET_MessageHeader *message) {
 364     unhijack(dnsoutport);
 365     GNUNET_SCHEDULER_add_delayed(GNUNET_TIME_UNIT_SECONDS, hijack, NULL);
 366
 367     GNUNET_SERVER_receive_done(client, GNUNET_OK);
 368 }
 369
 370 /**
 371  * This receives the dns-payload from the daemon-vpn and sends it on over the udp-socket
 372  */
 373 static void
 374 receive_query(void *cls,
 375               struct GNUNET_SERVER_Client *client,
 376               const struct GNUNET_MessageHeader *message) {
 377     struct query_packet* pkt = (struct query_packet*)message;
 378     struct dns_pkt* dns = (struct dns_pkt*)pkt->data;
 379     struct dns_pkt_parsed* pdns = parse_dns_packet(dns);
 380
 381     query_states[dns->s.id].valid = GNUNET_YES;
 382     query_states[dns->s.id].client = client;
 383     query_states[dns->s.id].local_ip = pkt->orig_from;
 384     query_states[dns->s.id].local_port = pkt->src_port;
 385     query_states[dns->s.id].remote_ip = pkt->orig_to;
 386     query_states[dns->s.id].namelen = strlen((char*)dns->data) + 1;
 387     query_states[dns->s.id].name = GNUNET_malloc(query_states[dns->s.id].namelen);
 388     memcpy(query_states[dns->s.id].name, dns->data, query_states[dns->s.id].namelen);
 389
 390     /* The query is for a .gnunet-address */
 391     if (pdns->queries[0]->namelen > 9 &&
 392         0 == strncmp(pdns->queries[0]->name+(pdns->queries[0]->namelen - 9), ".gnunet.", 9))
 393       {
 394         GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "Query for .gnunet!\n");
 395         GNUNET_HashCode key;
 396         GNUNET_CRYPTO_hash(pdns->queries[0]->name, pdns->queries[0]->namelen, &key);
 397
 398         GNUNET_log(GNUNET_ERROR_TYPE_DEBUG,
 399                    "Getting with key %08x, len is %d\n",
 400                    *((unsigned int*)&key),
 401                    pdns->queries[0]->namelen);
 402
 403         struct receive_dht_cls* cls = GNUNET_malloc(sizeof(struct receive_dht_cls));
 404         cls->id = dns->s.id;
 405
 406         cls->handle = GNUNET_DHT_get_start(dht,
 407                                            GNUNET_TIME_UNIT_MINUTES,
 408                                            GNUNET_BLOCK_TYPE_DNS,
 409                                            &key,
 410                                            DEFAULT_GET_REPLICATION,
 411                                            GNUNET_DHT_RO_NONE,
 412                                            NULL,
 413                                            0,
 414                                            NULL,
 415                                            0,
 416                                            receive_dht,
 417                                            cls);
 418
 419         goto outfree;
 420       }
 421
 422     GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "Query for '%s'; namelen=%d\n", pdns->queries[0]->name, pdns->queries[0]->namelen);
 423     /* The query is for a PTR of a previosly resolved virtual IP */
 424     if (htons(pdns->queries[0]->qtype) == 12 &&
 425         74 == pdns->queries[0]->namelen)
 426       {
 427         char* ipv6addr;
 428         char ipv6[16];
 429         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.";
 430         unsigned int i;
 431         unsigned long long ipv6prefix;
 432         unsigned int comparelen;
 433
 434         GNUNET_assert(GNUNET_OK == GNUNET_CONFIGURATION_get_value_string(cfg, "vpn", "IPV6ADDR", &ipv6addr));
 435         inet_pton (AF_INET6, ipv6addr, ipv6);
 436         GNUNET_free(ipv6addr);
 437
 438         GNUNET_assert(GNUNET_OK == GNUNET_CONFIGURATION_get_value_number(cfg, "vpn", "IPV6PREFIX", &ipv6prefix));
 439         GNUNET_assert(ipv6prefix < 127);
 440         ipv6prefix = (ipv6prefix + 7)/8;
 441
 442         for (i = ipv6prefix; i < 16; i++)
 443           ipv6[i] = 0;
 444
 445         for (i = 0; i < 16; i++)
 446           {
 447             unsigned char c1 = ipv6[i] >> 4;
 448             unsigned char c2 = ipv6[i] & 0xf;
 449
 450             if (c1 <= 9)
 451               ipv6rev[62-(4*i)] = c1 + '0';
 452             else
 453               ipv6rev[62-(4*i)] = c1 + 87; /* 87 is the difference between 'a' and 10 */
 454
 455             if (c2 <= 9)
 456               ipv6rev[62-((4*i)+2)] = c2 + '0';
 457             else
 458               ipv6rev[62-((4*i)+2)] = c2 + 87;
 459           }
 460         GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "My network is %s'.\n", ipv6rev);
 461         comparelen = 10 + 4*ipv6prefix;
 462         if(0 == strncmp(pdns->queries[0]->name+(pdns->queries[0]->namelen - comparelen),
 463                         ipv6rev + (74 - comparelen),
 464                         comparelen))
 465           {
 466             GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "Reverse-Query for .gnunet!\n");
 467
 468             GNUNET_SCHEDULER_add_now(send_rev_query, pdns);
 469
 470             goto out;
 471           }
 472       }
 473
 474     /* The query should be sent to the network */
 475
 476     struct sockaddr_in dest;
 477     memset(&dest, 0, sizeof dest);
 478     dest.sin_port = htons(53);
 479     dest.sin_addr.s_addr = pkt->orig_to;
 480
 481     GNUNET_NETWORK_socket_sendto(dnsout,
 482                                  dns,
 483                                  ntohs(pkt->hdr.size) - sizeof(struct query_packet) + 1,
 484                                  (struct sockaddr*) &dest,
 485                                  sizeof dest);
 486
 487 outfree:
 488     free_parsed_dns_packet(pdns);
 489     pdns = NULL;
 490 out:
 491     GNUNET_SERVER_receive_done(client, GNUNET_OK);
 492 }
 493
 494 /**
 495  * Read a response-packet of the UDP-Socket
 496  */
 497 static void
 498 read_response (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc) {
 499     unsigned char buf[65536];
 500     struct dns_pkt* dns = (struct dns_pkt*)buf;
 501
 502     if (tc->reason & GNUNET_SCHEDULER_REASON_SHUTDOWN)
 503       return;
 504
 505     struct sockaddr_in addr;
 506     memset(&addr, 0, sizeof addr);
 507     socklen_t addrlen = sizeof addr;
 508
 509     int r;
 510     r = GNUNET_NETWORK_socket_recvfrom(dnsout,
 511                                        buf,
 512                                        65536,
 513                                        (struct sockaddr*)&addr,
 514                                        &addrlen);
 515
 516     /* if (r < 0) FIXME */
 517
 518     if (query_states[dns->s.id].valid == GNUNET_YES) {
 519         query_states[dns->s.id].valid = GNUNET_NO;
 520
 521         size_t len = sizeof(struct answer_packet) + r - 1; /* 1 for the unsigned char data[1]; */
 522         struct answer_packet_list* answer = GNUNET_malloc(len + 2*sizeof(struct answer_packet_list*));
 523         answer->pkt.hdr.type = htons(GNUNET_MESSAGE_TYPE_LOCAL_RESPONSE_DNS);
 524         answer->pkt.hdr.size = htons(len);
 525         answer->pkt.subtype = GNUNET_DNS_ANSWER_TYPE_IP;
 526         answer->pkt.from = addr.sin_addr.s_addr;
 527         answer->pkt.to = query_states[dns->s.id].local_ip;
 528         answer->pkt.dst_port = query_states[dns->s.id].local_port;
 529         memcpy(answer->pkt.data, buf, r);
 530
 531         GNUNET_CONTAINER_DLL_insert_after(head, tail, tail, answer);
 532
 533         GNUNET_SERVER_notify_transmit_ready(query_states[dns->s.id].client,
 534                                             len,
 535                                             GNUNET_TIME_UNIT_FOREVER_REL,
 536                                             &send_answer,
 537                                             query_states[dns->s.id].client);
 538     }
 539
 540     GNUNET_SCHEDULER_add_read_net(GNUNET_TIME_UNIT_FOREVER_REL,
 541                                   dnsout,
 542                                   &read_response,
 543                                   NULL);
 544 }
 545
 546
 547 /**
 548  * Task run during shutdown.
 549  *
 550  * @param cls unused
 551  * @param tc unused
 552  */
 553 static void
 554 cleanup_task (void *cls,
 555               const struct GNUNET_SCHEDULER_TaskContext *tc)
 556 {
 557   unhijack(dnsoutport);
 558   GNUNET_DHT_disconnect(dht);
 559 }
 560
 561 /**
 562  * Publish a DNS-record in the DHT. This is up to now just for testing.
 563  */
 564 static void
 565 publish_name (void *cls,
 566               const struct GNUNET_SCHEDULER_TaskContext *tc) {
 567     if (0 != (tc->reason & GNUNET_SCHEDULER_REASON_SHUTDOWN))
 568       return;
 569
 570     char* name = "philipptoelke.gnunet.";
 571     size_t size = sizeof(struct GNUNET_DNS_Record);
 572     struct GNUNET_DNS_Record data;
 573     memset(&data, 0, size);
 574
 575     data.purpose.size = htonl(size - sizeof(struct GNUNET_CRYPTO_RsaSignature));
 576     data.purpose.purpose = GNUNET_SIGNATURE_PURPOSE_DNS_RECORD;
 577
 578     GNUNET_CRYPTO_hash(name, strlen(name)+1, &data.service_descriptor);
 579
 580     data.service_type = htonl(GNUNET_DNS_SERVICE_TYPE_UDP);
 581     data.ports = htons(69);
 582
 583     char* keyfile;
 584     if (GNUNET_OK != GNUNET_CONFIGURATION_get_value_filename(cfg, "GNUNETD",
 585                                                              "HOSTKEY", &keyfile))
 586       {
 587         GNUNET_log(GNUNET_ERROR_TYPE_ERROR, "could not read keyfile-value\n");
 588         if (keyfile != NULL) GNUNET_free(keyfile);
 589         return;
 590       }
 591
 592     struct GNUNET_CRYPTO_RsaPrivateKey *my_private_key = GNUNET_CRYPTO_rsa_key_create_from_file(keyfile);
 593     GNUNET_free(keyfile);
 594     GNUNET_assert(my_private_key != NULL);
 595
 596     GNUNET_CRYPTO_rsa_key_get_public(my_private_key, &data.peer);
 597
 598     data.expiration_time = GNUNET_TIME_relative_to_absolute(GNUNET_TIME_UNIT_HOURS);
 599
 600   /* Sign the block */
 601     if (GNUNET_OK != GNUNET_CRYPTO_rsa_sign(my_private_key,
 602                                             &data.purpose,
 603                                             &data.signature))
 604       {
 605         GNUNET_log(GNUNET_ERROR_TYPE_ERROR, "could not sign DNS_Record\n");
 606         return;
 607       }
 608     GNUNET_CRYPTO_rsa_key_free(my_private_key);
 609
 610     GNUNET_log(GNUNET_ERROR_TYPE_DEBUG,
 611                "Putting with key %08x, size = %d\n",
 612                *((unsigned int*)&data.service_descriptor),
 613                size);
 614
 615     GNUNET_DHT_put(dht,
 616                    &data.service_descriptor,
 617                    DEFAULT_PUT_REPLICATION,
 618                    GNUNET_DHT_RO_NONE,
 619                    GNUNET_BLOCK_TYPE_DNS,
 620                    size,
 621                    (char*)&data,
 622                    GNUNET_TIME_relative_to_absolute(GNUNET_TIME_UNIT_HOURS),
 623                    GNUNET_TIME_UNIT_MINUTES,
 624                    NULL,
 625                    NULL);
 626
 627     GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_UNIT_HOURS,
 628                                   publish_name,
 629                                   NULL);
 630 }
 631
 632 /**
 633  * @param cls closure
 634  * @param server the initialized server
 635  * @param cfg_ configuration to use
 636  */
 637 static void
 638 run (void *cls,
 639      struct GNUNET_SERVER_Handle *server,
 640      const struct GNUNET_CONFIGURATION_Handle *cfg_)
 641 {
 642   static const struct GNUNET_SERVER_MessageHandler handlers[] = {
 643       /* callback, cls, type, size */
 644         {&receive_query, NULL, GNUNET_MESSAGE_TYPE_LOCAL_QUERY_DNS, 0},
 645         {&rehijack, NULL, GNUNET_MESSAGE_TYPE_REHIJACK, sizeof(struct GNUNET_MessageHeader)},
 646         {NULL, NULL, 0, 0}
 647   };
 648
 649   cfg = cfg_;
 650
 651   unsigned int i;
 652   for (i = 0; i < 65536; i++) {
 653       query_states[i].valid = GNUNET_NO;
 654   }
 655
 656   dht = GNUNET_DHT_connect(cfg, 1024);
 657
 658   struct sockaddr_in addr;
 659
 660   dnsout = GNUNET_NETWORK_socket_create (AF_INET, SOCK_DGRAM, 0);
 661   if (dnsout == NULL)
 662     return;
 663   memset(&addr, 0, sizeof(struct sockaddr_in));
 664
 665   int err = GNUNET_NETWORK_socket_bind (dnsout,
 666                                         (struct sockaddr*)&addr,
 667                                         sizeof(struct sockaddr_in));
 668
 669   if (err != GNUNET_YES) {
 670       GNUNET_log(GNUNET_ERROR_TYPE_ERROR, "Could not bind a port, exiting\n");
 671       return;
 672   }
 673
 674   /* Read the port we bound to */
 675   socklen_t addrlen = sizeof(struct sockaddr_in);
 676   err = getsockname(GNUNET_NETWORK_get_fd(dnsout),
 677                     (struct sockaddr*) &addr,
 678                     &addrlen);
 679
 680   dnsoutport = htons(addr.sin_port);
 681
 682   GNUNET_SCHEDULER_add_now (publish_name, NULL);
 683
 684   GNUNET_SCHEDULER_add_read_net(GNUNET_TIME_UNIT_FOREVER_REL, dnsout, &read_response, NULL);
 685
 686   GNUNET_SERVER_add_handlers (server, handlers);
 687   GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_UNIT_FOREVER_REL,
 688                                 &cleanup_task,
 689                                 cls);
 690 }
 691
 692 /**
 693  * The main function for the dns service.
 694  *
 695  * @param argc number of arguments from the command line
 696  * @param argv command line arguments
 697  * @return 0 ok, 1 on error
 698  */
 699 int
 700 main (int argc, char *const *argv)
 701 {
 702   return (GNUNET_OK ==
 703           GNUNET_SERVICE_run (argc,
 704                               argv,
 705                               "dns",
 706                               GNUNET_SERVICE_OPTION_NONE,
 707                               &run, NULL)) ? 0 : 1;
 708 }