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     drec_data->ttl = htonl(3600); /* FIXME: read from block */
 249
 250     /* Calculate at which offset in the packet the length of the name and the
 251      * name, it is filled in by the daemon-vpn */
 252     answer->pkt.addroffset = htons((unsigned short)((unsigned long)(&drec_data->data_len)-(unsigned long)(&answer->pkt)));
 253
 254     GNUNET_CONTAINER_DLL_insert_after(head, tail, tail, answer);
 255
 256     GNUNET_SERVER_notify_transmit_ready(query_states[id].client,
 257                                         len,
 258                                         GNUNET_TIME_UNIT_FOREVER_REL,
 259                                         &send_answer,
 260                                         query_states[id].client);
 261
 262     /*
 263      * build
 264      * complete dns-packet with empty name in the answer
 265      * provide offsett of the name
 266      */
 267 }
 268
 269 /**
 270  * Receive a block from the dht.
 271  */
 272 static void
 273 receive_dht(void *cls,
 274             struct GNUNET_TIME_Absolute exp,
 275             const GNUNET_HashCode *key,
 276             const struct GNUNET_PeerIdentity *const *get_path,
 277             const struct GNUNET_PeerIdentity *const *put_path,
 278             enum GNUNET_BLOCK_Type type,
 279             size_t size,
 280             const void *data) {
 281
 282     unsigned short id = ((struct receive_dht_cls*)cls)->id;
 283     struct GNUNET_DHT_GetHandle* handle = ((struct receive_dht_cls*)cls)->handle;
 284     GNUNET_free(cls);
 285
 286     GNUNET_assert(type == GNUNET_BLOCK_TYPE_DNS);
 287
 288     /* If no query with this id is pending, ignore the block */
 289     if (query_states[id].valid != GNUNET_YES) return;
 290     query_states[id].valid = GNUNET_NO;
 291
 292     const struct GNUNET_DNS_Record* rec = data;
 293     GNUNET_log(GNUNET_ERROR_TYPE_DEBUG,
 294                "Got block of size %d, peer: %08x, desc: %08x\n",
 295                size,
 296                *((unsigned int*)&rec->peer),
 297                *((unsigned int*)&rec->service_descriptor));
 298
 299     size_t len = sizeof(struct answer_packet) - 1 \
 300                  + sizeof(struct dns_static) \
 301                  + query_states[id].namelen \
 302                  + sizeof(struct dns_query_line) \
 303                  + 2 /* To hold the pointer (as defined in RFC1035) to the name */ \
 304                  + sizeof(struct dns_record_line) - 1 \
 305                  + 16; /* To hold the IPv6-Address */
 306
 307     struct answer_packet_list* answer = GNUNET_malloc(len + 2*sizeof(struct answer_packet_list*));
 308     memset(answer, 0, len + 2*sizeof(struct answer_packet_list*));
 309
 310     answer->pkt.hdr.type = htons(GNUNET_MESSAGE_TYPE_LOCAL_RESPONSE_DNS);
 311     answer->pkt.hdr.size = htons(len);
 312     answer->pkt.subtype = GNUNET_DNS_ANSWER_TYPE_SERVICE;
 313
 314     GNUNET_CRYPTO_hash(&rec->peer,
 315                        sizeof(struct GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded),
 316                        &answer->pkt.service_descr.peer);
 317
 318     memcpy(&answer->pkt.service_descr.service_descriptor,
 319            &rec->service_descriptor,
 320            sizeof(GNUNET_HashCode));
 321     memcpy(&answer->pkt.service_descr.service_type,
 322            &rec->service_type,
 323            sizeof(answer->pkt.service_descr.service_type));
 324     memcpy(&answer->pkt.service_descr.ports, &rec->ports, sizeof(answer->pkt.service_descr.ports));
 325
 326     answer->pkt.from = query_states[id].remote_ip;
 327
 328     answer->pkt.to = query_states[id].local_ip;
 329     answer->pkt.dst_port = query_states[id].local_port;
 330
 331     struct dns_pkt *dpkt = (struct dns_pkt*)answer->pkt.data;
 332
 333     dpkt->s.id = id;
 334     dpkt->s.aa = 1;
 335     dpkt->s.qr = 1;
 336     dpkt->s.ra = 1;
 337     dpkt->s.qdcount = htons(1);
 338     dpkt->s.ancount = htons(1);
 339
 340     memcpy(dpkt->data, query_states[id].name, query_states[id].namelen);
 341     GNUNET_free(query_states[id].name);
 342
 343     struct dns_query_line* dque = (struct dns_query_line*)(dpkt->data+(query_states[id].namelen));
 344     dque->type = htons(28); /* AAAA */
 345     dque->class = htons(1); /* IN */
 346
 347     char* anname = (char*)(dpkt->data+(query_states[id].namelen)+sizeof(struct dns_query_line));
 348     memcpy(anname, (char[]){0xc0, 0x0c}, 2);
 349
 350     struct dns_record_line *drec_data = (struct dns_record_line*)(dpkt->data+(query_states[id].namelen)+sizeof(struct dns_query_line)+2);
 351     drec_data->type = htons(28); /* AAAA */
 352     drec_data->class = htons(1); /* IN */
 353     drec_data->ttl = htonl(3600); /* FIXME: read from block */
 354     drec_data->data_len = htons(16);
 355
 356     /* Calculate at which offset in the packet the IPv6-Address belongs, it is
 357      * filled in by the daemon-vpn */
 358     answer->pkt.addroffset = htons((unsigned short)((unsigned long)(&drec_data->data)-(unsigned long)(&answer->pkt)));
 359
 360     GNUNET_CONTAINER_DLL_insert_after(head, tail, tail, answer);
 361
 362     GNUNET_SERVER_notify_transmit_ready(query_states[id].client,
 363                                         len,
 364                                         GNUNET_TIME_UNIT_FOREVER_REL,
 365                                         &send_answer,
 366                                         query_states[id].client);
 367
 368     GNUNET_DHT_get_stop(handle);
 369 }
 370
 371 /**
 372  * This receives a GNUNET_MESSAGE_TYPE_REHIJACK and rehijacks the DNS
 373  */
 374 static void
 375 rehijack(void *cls,
 376          struct GNUNET_SERVER_Client *client,
 377          const struct GNUNET_MessageHeader *message) {
 378     unhijack(dnsoutport);
 379     GNUNET_SCHEDULER_add_delayed(GNUNET_TIME_UNIT_SECONDS, hijack, NULL);
 380
 381     GNUNET_SERVER_receive_done(client, GNUNET_OK);
 382 }
 383
 384 /**
 385  * This receives the dns-payload from the daemon-vpn and sends it on over the udp-socket
 386  */
 387 static void
 388 receive_query(void *cls,
 389               struct GNUNET_SERVER_Client *client,
 390               const struct GNUNET_MessageHeader *message) {
 391     struct query_packet* pkt = (struct query_packet*)message;
 392     struct dns_pkt* dns = (struct dns_pkt*)pkt->data;
 393     struct dns_pkt_parsed* pdns = parse_dns_packet(dns);
 394
 395     query_states[dns->s.id].valid = GNUNET_YES;
 396     query_states[dns->s.id].client = client;
 397     query_states[dns->s.id].local_ip = pkt->orig_from;
 398     query_states[dns->s.id].local_port = pkt->src_port;
 399     query_states[dns->s.id].remote_ip = pkt->orig_to;
 400     query_states[dns->s.id].namelen = strlen((char*)dns->data) + 1;
 401     query_states[dns->s.id].name = GNUNET_malloc(query_states[dns->s.id].namelen);
 402     memcpy(query_states[dns->s.id].name, dns->data, query_states[dns->s.id].namelen);
 403
 404     /* The query is for a .gnunet-address */
 405     if (pdns->queries[0]->namelen > 9 &&
 406         0 == strncmp(pdns->queries[0]->name+(pdns->queries[0]->namelen - 9), ".gnunet.", 9))
 407       {
 408         GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "Query for .gnunet!\n");
 409         GNUNET_HashCode key;
 410         GNUNET_CRYPTO_hash(pdns->queries[0]->name, pdns->queries[0]->namelen, &key);
 411
 412         GNUNET_log(GNUNET_ERROR_TYPE_DEBUG,
 413                    "Getting with key %08x, len is %d\n",
 414                    *((unsigned int*)&key),
 415                    pdns->queries[0]->namelen);
 416
 417         struct receive_dht_cls* cls = GNUNET_malloc(sizeof(struct receive_dht_cls));
 418         cls->id = dns->s.id;
 419
 420         cls->handle = GNUNET_DHT_get_start(dht,
 421                                            GNUNET_TIME_UNIT_MINUTES,
 422                                            GNUNET_BLOCK_TYPE_DNS,
 423                                            &key,
 424                                            DEFAULT_GET_REPLICATION,
 425                                            GNUNET_DHT_RO_NONE,
 426                                            NULL,
 427                                            0,
 428                                            NULL,
 429                                            0,
 430                                            receive_dht,
 431                                            cls);
 432
 433         goto outfree;
 434       }
 435
 436     GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "Query for '%s'; namelen=%d\n", pdns->queries[0]->name, pdns->queries[0]->namelen);
 437     /* The query is for a PTR of a previosly resolved virtual IP */
 438     if (htons(pdns->queries[0]->qtype) == 12 &&
 439         74 == pdns->queries[0]->namelen)
 440       {
 441         char* ipv6addr;
 442         char ipv6[16];
 443         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.";
 444         unsigned int i;
 445         unsigned long long ipv6prefix;
 446         unsigned int comparelen;
 447
 448         GNUNET_assert(GNUNET_OK == GNUNET_CONFIGURATION_get_value_string(cfg, "vpn", "IPV6ADDR", &ipv6addr));
 449         inet_pton (AF_INET6, ipv6addr, ipv6);
 450         GNUNET_free(ipv6addr);
 451
 452         GNUNET_assert(GNUNET_OK == GNUNET_CONFIGURATION_get_value_number(cfg, "vpn", "IPV6PREFIX", &ipv6prefix));
 453         GNUNET_assert(ipv6prefix < 127);
 454         ipv6prefix = (ipv6prefix + 7)/8;
 455
 456         for (i = ipv6prefix; i < 16; i++)
 457           ipv6[i] = 0;
 458
 459         for (i = 0; i < 16; i++)
 460           {
 461             unsigned char c1 = ipv6[i] >> 4;
 462             unsigned char c2 = ipv6[i] & 0xf;
 463
 464             if (c1 <= 9)
 465               ipv6rev[62-(4*i)] = c1 + '0';
 466             else
 467               ipv6rev[62-(4*i)] = c1 + 87; /* 87 is the difference between 'a' and 10 */
 468
 469             if (c2 <= 9)
 470               ipv6rev[62-((4*i)+2)] = c2 + '0';
 471             else
 472               ipv6rev[62-((4*i)+2)] = c2 + 87;
 473           }
 474         GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "My network is %s'.\n", ipv6rev);
 475         comparelen = 10 + 4*ipv6prefix;
 476         if(0 == strncmp(pdns->queries[0]->name+(pdns->queries[0]->namelen - comparelen),
 477                         ipv6rev + (74 - comparelen),
 478                         comparelen))
 479           {
 480             GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "Reverse-Query for .gnunet!\n");
 481
 482             GNUNET_SCHEDULER_add_now(send_rev_query, pdns);
 483
 484             goto out;
 485           }
 486       }
 487
 488     /* The query should be sent to the network */
 489
 490     struct sockaddr_in dest;
 491     memset(&dest, 0, sizeof dest);
 492     dest.sin_port = htons(53);
 493     dest.sin_addr.s_addr = pkt->orig_to;
 494
 495     GNUNET_NETWORK_socket_sendto(dnsout,
 496                                  dns,
 497                                  ntohs(pkt->hdr.size) - sizeof(struct query_packet) + 1,
 498                                  (struct sockaddr*) &dest,
 499                                  sizeof dest);
 500
 501 outfree:
 502     free_parsed_dns_packet(pdns);
 503     pdns = NULL;
 504 out:
 505     GNUNET_SERVER_receive_done(client, GNUNET_OK);
 506 }
 507
 508 static void read_response (void *cls,
 509                            const struct GNUNET_SCHEDULER_TaskContext *tc);
 510
 511 static void
 512 open_port ()
 513 {
 514   struct sockaddr_in addr;
 515
 516   dnsout = GNUNET_NETWORK_socket_create (AF_INET, SOCK_DGRAM, 0);
 517   if (dnsout == NULL)
 518     return;
 519   memset (&addr, 0, sizeof (struct sockaddr_in));
 520
 521   int err = GNUNET_NETWORK_socket_bind (dnsout,
 522                                         (struct sockaddr *) &addr,
 523                                         sizeof (struct sockaddr_in));
 524
 525   if (err != GNUNET_YES)
 526     {
 527       GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
 528                   "Could not bind a port, exiting\n");
 529       return;
 530     }
 531
 532   /* Read the port we bound to */
 533   socklen_t addrlen = sizeof (struct sockaddr_in);
 534   err = getsockname (GNUNET_NETWORK_get_fd (dnsout),
 535                      (struct sockaddr *) &addr, &addrlen);
 536
 537   dnsoutport = htons (addr.sin_port);
 538
 539   GNUNET_SCHEDULER_add_read_net (GNUNET_TIME_UNIT_FOREVER_REL, dnsout,
 540                                  &read_response, NULL);
 541 }
 542
 543 /**
 544  * Read a response-packet of the UDP-Socket
 545  */
 546 static void
 547 read_response (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc) {
 548     struct sockaddr_in addr;
 549     socklen_t addrlen = sizeof (addr);
 550     int r;
 551     int len;
 552
 553     if (tc->reason & GNUNET_SCHEDULER_REASON_SHUTDOWN)
 554       return;
 555
 556     memset(&addr, 0, sizeof addr);
 557
 558 #ifndef MINGW
 559     if (0 != ioctl (GNUNET_NETWORK_get_fd (dnsout),
 560                     FIONREAD, &len))
 561       {
 562         unhijack(dnsoutport);
 563         open_port();
 564         GNUNET_SCHEDULER_add_delayed(GNUNET_TIME_UNIT_SECONDS, hijack, NULL);
 565         return;
 566       }
 567 #else
 568     /* port the code above? */
 569     len = 65536;
 570 #endif
 571     {
 572       unsigned char buf[len];
 573       struct dns_pkt* dns = (struct dns_pkt*)buf;
 574
 575       r = GNUNET_NETWORK_socket_recvfrom (dnsout,
 576                                           buf,
 577                                           sizeof (buf),
 578                                           (struct sockaddr*)&addr,
 579                                           &addrlen);
 580
 581       if (r < 0)
 582         {
 583           unhijack(dnsoutport);
 584           open_port();
 585           GNUNET_SCHEDULER_add_delayed(GNUNET_TIME_UNIT_SECONDS, hijack, NULL);
 586           return;
 587         }
 588
 589       if (query_states[dns->s.id].valid == GNUNET_YES)
 590         {
 591           query_states[dns->s.id].valid = GNUNET_NO;
 592
 593           size_t len = sizeof(struct answer_packet) + r - 1; /* 1 for the unsigned char data[1]; */
 594           struct answer_packet_list* answer = GNUNET_malloc(len + 2*sizeof(struct answer_packet_list*));
 595           answer->pkt.hdr.type = htons(GNUNET_MESSAGE_TYPE_LOCAL_RESPONSE_DNS);
 596           answer->pkt.hdr.size = htons(len);
 597           answer->pkt.subtype = GNUNET_DNS_ANSWER_TYPE_IP;
 598           answer->pkt.from = addr.sin_addr.s_addr;
 599           answer->pkt.to = query_states[dns->s.id].local_ip;
 600           answer->pkt.dst_port = query_states[dns->s.id].local_port;
 601           memcpy(answer->pkt.data, buf, r);
 602
 603           GNUNET_CONTAINER_DLL_insert_after(head, tail, tail, answer);
 604
 605           GNUNET_SERVER_notify_transmit_ready(query_states[dns->s.id].client,
 606                                               len,
 607                                               GNUNET_TIME_UNIT_FOREVER_REL,
 608                                               &send_answer,
 609                                               query_states[dns->s.id].client);
 610         }
 611     }
 612     GNUNET_SCHEDULER_add_read_net(GNUNET_TIME_UNIT_FOREVER_REL,
 613                                   dnsout,
 614                                   &read_response,
 615                                   NULL);
 616 }
 617
 618
 619 /**
 620  * Task run during shutdown.
 621  *
 622  * @param cls unused
 623  * @param tc unused
 624  */
 625 static void
 626 cleanup_task (void *cls,
 627               const struct GNUNET_SCHEDULER_TaskContext *tc)
 628 {
 629   unhijack(dnsoutport);
 630   GNUNET_DHT_disconnect(dht);
 631 }
 632
 633 /**
 634  * @brief Create a port-map from udp and tcp redirects
 635  *
 636  * @param udp_redirects
 637  * @param tcp_redirects
 638  *
 639  * @return
 640  */
 641 uint64_t
 642 get_port_from_redirects (const char *udp_redirects, const char *tcp_redirects)
 643 {
 644   uint64_t ret = 0;
 645   char* cpy, *hostname, *redirect;
 646   int local_port, count = 0;
 647
 648   if (NULL != udp_redirects)
 649     {
 650       cpy = GNUNET_strdup (udp_redirects);
 651       for (redirect = strtok (cpy, " "); redirect != NULL; redirect = strtok (NULL, " "))
 652         {
 653           if (NULL == (hostname = strstr (redirect, ":")))
 654             {
 655               GNUNET_log(GNUNET_ERROR_TYPE_WARNING, "Warning: option %s is not formatted correctly!\n", redirect);
 656               continue;
 657             }
 658           hostname[0] = '\0';
 659           local_port = atoi (redirect);
 660           if (!((local_port > 0) && (local_port < 65536)))
 661             GNUNET_log(GNUNET_ERROR_TYPE_WARNING, "Warning: %s is not a correct port.", redirect);
 662
 663           ret |= (0xFFFF & htons(local_port));
 664           ret <<= 16;
 665           count ++;
 666
 667           if(count > 4)
 668             {
 669               ret = 0;
 670               goto out;
 671             }
 672         }
 673       GNUNET_free(cpy);
 674       cpy = NULL;
 675     }
 676
 677   if (NULL != tcp_redirects)
 678     {
 679       cpy = GNUNET_strdup (tcp_redirects);
 680       for (redirect = strtok (cpy, " "); redirect != NULL; redirect = strtok (NULL, " "))
 681         {
 682           if (NULL == (hostname = strstr (redirect, ":")))
 683             {
 684               GNUNET_log(GNUNET_ERROR_TYPE_WARNING, "Warning: option %s is not formatted correctly!\n", redirect);
 685               continue;
 686             }
 687           hostname[0] = '\0';
 688           local_port = atoi (redirect);
 689           if (!((local_port > 0) && (local_port < 65536)))
 690             GNUNET_log(GNUNET_ERROR_TYPE_WARNING, "Warning: %s is not a correct port.", redirect);
 691
 692           ret |= (0xFFFF & htons(local_port));
 693           ret <<= 16;
 694           count ++;
 695
 696           if(count > 4)
 697             {
 698               ret = 0;
 699               goto out;
 700             }
 701         }
 702       GNUNET_free(cpy);
 703       cpy = NULL;
 704     }
 705
 706 out:
 707   if (NULL != cpy)
 708     GNUNET_free(cpy);
 709   return ret;
 710 }
 711
 712 void
 713 publish_name (const char *name, uint64_t ports, uint32_t service_type,
 714               struct GNUNET_CRYPTO_RsaPrivateKey *my_private_key)
 715 {
 716   size_t size = sizeof (struct GNUNET_DNS_Record);
 717   struct GNUNET_DNS_Record data;
 718   memset (&data, 0, size);
 719
 720   data.purpose.size =
 721     htonl (size - sizeof (struct GNUNET_CRYPTO_RsaSignature));
 722   data.purpose.purpose = GNUNET_SIGNATURE_PURPOSE_DNS_RECORD;
 723
 724   GNUNET_CRYPTO_hash (name, strlen (name) + 1, &data.service_descriptor);
 725   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Store with key1 %x\n",
 726               *((unsigned long long *) &data.service_descriptor));
 727
 728   data.service_type = service_type;
 729   data.ports = ports;
 730
 731   GNUNET_CRYPTO_rsa_key_get_public (my_private_key, &data.peer);
 732
 733   data.expiration_time =
 734     GNUNET_TIME_relative_to_absolute (GNUNET_TIME_relative_multiply(GNUNET_TIME_UNIT_HOURS, 2));
 735
 736   /* Sign the block */
 737   if (GNUNET_OK != GNUNET_CRYPTO_rsa_sign (my_private_key,
 738                                            &data.purpose, &data.signature))
 739     {
 740       GNUNET_log (GNUNET_ERROR_TYPE_ERROR, "could not sign DNS_Record\n");
 741       return;
 742     }
 743
 744   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
 745               "Putting with key %08x, size = %d\n",
 746               *((unsigned int *) &data.service_descriptor), size);
 747
 748   GNUNET_DHT_put (dht,
 749                   &data.service_descriptor,
 750                   DEFAULT_PUT_REPLICATION,
 751                   GNUNET_DHT_RO_NONE,
 752                   GNUNET_BLOCK_TYPE_DNS,
 753                   size,
 754                   (char *) &data,
 755                   GNUNET_TIME_relative_to_absolute (GNUNET_TIME_UNIT_HOURS),
 756                   GNUNET_TIME_UNIT_MINUTES, NULL, NULL);
 757 }
 758
 759 /**
 760  * @brief Publishes the record defined by the section section
 761  *
 762  * @param cls closure
 763  * @param section the current section
 764  */
 765 void
 766 publish_iterate (void *cls, const char *section)
 767 {
 768   char *udp_redirects, *tcp_redirects, *alternative_names, *alternative_name,
 769     *keyfile;
 770
 771   GNUNET_CONFIGURATION_get_value_string (servicecfg, section,
 772                                          "UDP_REDIRECTS", &udp_redirects);
 773   GNUNET_CONFIGURATION_get_value_string (servicecfg, section, "TCP_REDIRECTS",
 774                                          &tcp_redirects);
 775
 776   if (GNUNET_OK != GNUNET_CONFIGURATION_get_value_filename (cfg, "GNUNETD",
 777                                                             "HOSTKEY",
 778                                                             &keyfile))
 779     {
 780       GNUNET_log (GNUNET_ERROR_TYPE_ERROR, "could not read keyfile-value\n");
 781       if (keyfile != NULL)
 782         GNUNET_free (keyfile);
 783       return;
 784     }
 785
 786   struct GNUNET_CRYPTO_RsaPrivateKey *my_private_key =
 787     GNUNET_CRYPTO_rsa_key_create_from_file (keyfile);
 788   GNUNET_free (keyfile);
 789   GNUNET_assert (my_private_key != NULL);
 790
 791   uint64_t ports = get_port_from_redirects (udp_redirects, tcp_redirects);
 792   uint32_t service_type = 0;
 793
 794   if (NULL != udp_redirects)
 795     service_type = GNUNET_DNS_SERVICE_TYPE_UDP;
 796
 797   if (NULL != tcp_redirects)
 798     service_type |= GNUNET_DNS_SERVICE_TYPE_TCP;
 799
 800   service_type = htonl (service_type);
 801
 802
 803   publish_name (section, ports, service_type, my_private_key);
 804
 805   GNUNET_CONFIGURATION_get_value_string (servicecfg, section,
 806                                          "ALTERNATIVE_NAMES",
 807                                          &alternative_names);
 808   for (alternative_name = strtok (alternative_names, " ");
 809        alternative_name != NULL; alternative_name = strtok (NULL, " "))
 810     {
 811       char *altname =
 812         alloca (strlen (alternative_name) + strlen (section) + 1 + 1);
 813       strcpy (altname, alternative_name);
 814       strcpy (altname + strlen (alternative_name) + 1, section);
 815       altname[strlen (alternative_name)] = '.';
 816
 817       publish_name (altname, ports, service_type, my_private_key);
 818     }
 819
 820   GNUNET_free_non_null(alternative_names);
 821   GNUNET_CRYPTO_rsa_key_free (my_private_key);
 822   GNUNET_free_non_null (udp_redirects);
 823   GNUNET_free_non_null (tcp_redirects);
 824 }
 825
 826 /**
 827  * Publish a DNS-record in the DHT. This is up to now just for testing.
 828  */
 829 static void
 830 publish_names (void *cls,
 831                const struct GNUNET_SCHEDULER_TaskContext *tc) {
 832     char *services;
 833     if (0 != (tc->reason & GNUNET_SCHEDULER_REASON_SHUTDOWN))
 834       return;
 835
 836     if (NULL != servicecfg)
 837       GNUNET_CONFIGURATION_destroy(servicecfg);
 838
 839     GNUNET_CONFIGURATION_get_value_filename(cfg, "dns", "SERVICES", &services);
 840
 841     servicecfg = GNUNET_CONFIGURATION_create();
 842     if (GNUNET_OK == GNUNET_CONFIGURATION_parse(servicecfg, services))
 843       {
 844         GNUNET_log(GNUNET_ERROR_TYPE_INFO, "Parsing services %s\n", services);
 845         GNUNET_CONFIGURATION_iterate_sections(servicecfg, publish_iterate, NULL);
 846       }
 847     if (NULL != services)
 848       GNUNET_free(services);
 849
 850     GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_UNIT_HOURS,
 851                                   publish_names,
 852                                   NULL);
 853 }
 854
 855 /**
 856  * @param cls closure
 857  * @param server the initialized server
 858  * @param cfg_ configuration to use
 859  */
 860 static void
 861 run (void *cls,
 862      struct GNUNET_SERVER_Handle *server,
 863      const struct GNUNET_CONFIGURATION_Handle *cfg_)
 864 {
 865   static const struct GNUNET_SERVER_MessageHandler handlers[] = {
 866       /* callback, cls, type, size */
 867         {&receive_query, NULL, GNUNET_MESSAGE_TYPE_LOCAL_QUERY_DNS, 0},
 868         {&rehijack, NULL, GNUNET_MESSAGE_TYPE_REHIJACK, sizeof(struct GNUNET_MessageHeader)},
 869         {NULL, NULL, 0, 0}
 870   };
 871
 872   cfg = cfg_;
 873
 874   unsigned int i;
 875   for (i = 0; i < 65536; i++) {
 876       query_states[i].valid = GNUNET_NO;
 877   }
 878
 879   dht = GNUNET_DHT_connect(cfg, 1024);
 880
 881   open_port();
 882
 883   GNUNET_SCHEDULER_add_now (publish_names, NULL);
 884
 885   GNUNET_SERVER_add_handlers (server, handlers);
 886   GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_UNIT_FOREVER_REL,
 887                                 &cleanup_task,
 888                                 cls);
 889 }
 890
 891 /**
 892  * The main function for the dns service.
 893  *
 894  * @param argc number of arguments from the command line
 895  * @param argv command line arguments
 896  * @return 0 ok, 1 on error
 897  */
 898 int
 899 main (int argc, char *const *argv)
 900 {
 901   return (GNUNET_OK ==
 902           GNUNET_SERVICE_run (argc,
 903                               argv,
 904                               "dns",
 905                               GNUNET_SERVICE_OPTION_NONE,
 906                               &run, NULL)) ? 0 : 1;
 907 }