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