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path: root/src/vpn/gnunet-service-dns.c
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/*
     This file is part of GNUnet.
     (C) 2009 Christian Grothoff (and other contributing authors)

     GNUnet is free software; you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published
     by the Free Software Foundation; either version 3, or (at your
     option) any later version.

     GNUnet is distributed in the hope that it will be useful, but
     WITHOUT ANY WARRANTY; without even the implied warranty of
     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
     General Public License for more details.

     You should have received a copy of the GNU General Public License
     along with GNUnet; see the file COPYING.  If not, write to the
     Free Software Foundation, Inc., 59 Temple Place - Suite 330,
     Boston, MA 02111-1307, USA.
*/

/**
 * @file vpn/gnunet-service-dns.c
 * @author Philipp Toelke
 */
#include "platform.h"
#include "gnunet_getopt_lib.h"
#include "gnunet_service_lib.h"
#include <gnunet_constants.h>
#include "gnunet_network_lib.h"
#include "gnunet_os_lib.h"
#include "gnunet-service-dns-p.h"
#include "gnunet_connection_lib.h"
#include "gnunet_protocols.h"
#include "gnunet_applications.h"
#include "gnunet-vpn-packet.h"
#include "gnunet_container_lib.h"
#include "gnunet-dns-parser.h"
#include "gnunet_dht_service.h"
#include "gnunet_block_lib.h"
#include "block_dns.h"
#include "gnunet_crypto_lib.h"
#include "gnunet_mesh_service.h"
#include "gnunet_signatures.h"

struct GNUNET_MESH_Handle *mesh_handle;

struct GNUNET_CONNECTION_TransmitHandle *server_notify;

/**
 * The UDP-Socket through which DNS-Resolves will be sent if they are not to be
 * sent through gnunet. The port of this socket will not be hijacked.
 */
static struct GNUNET_NETWORK_Handle *dnsout;
static struct GNUNET_NETWORK_Handle *dnsout6;

/**
 * The port bound to the socket dnsout
 */
static unsigned short dnsoutport;

/**
 * A handle to the DHT-Service
 */
static struct GNUNET_DHT_Handle *dht;

/**
 * The configuration to use
 */
static const struct GNUNET_CONFIGURATION_Handle *cfg;

/**
 * A list of DNS-Responses that have to be sent to the requesting client
 */
static struct answer_packet_list *head;

/**
 * The tail of the list of DNS-responses
 */
static struct answer_packet_list *tail;

/**
 * A structure containing a mapping from network-byte-ordered DNS-id (16 bit) to
 * some information needed to handle this query
 *
 * It currently allocates at least
 * (1 + machine-width + machine-width + 32 + 32 + 16 + machine-width + 8) * 65536 bit
 * = 17 MiB on 64 bit.
 * = 11 MiB on 32 bit.
 */
static struct
{
  unsigned valid:1;
  struct GNUNET_SERVER_Client *client;
  struct GNUNET_MESH_Tunnel *tunnel;
  char local_ip[16];
  char remote_ip[16];
  char addrlen;
  uint16_t local_port;
  char *name;
  uint8_t namelen;
  uint16_t qtype;
} query_states[UINT16_MAX + 1];

/**
 * A struct used to give more than one value as
 * closure to receive_dht
 */
struct receive_dht_cls
{
  uint16_t id;
  struct GNUNET_DHT_GetHandle *handle;
};

struct tunnel_notify_queue
{
  struct tunnel_notify_queue *next;
  struct tunnel_notify_queue *prev;
  void *cls;
  size_t len;
  GNUNET_CONNECTION_TransmitReadyNotify cb;
};

struct tunnel_state
{
  struct tunnel_notify_queue *head, *tail;
  struct GNUNET_MESH_TransmitHandle *th;
};

static size_t
send_answer (void *cls, size_t size, void *buf);

static void
client_disconnect (void *cls, struct GNUNET_SERVER_Client *client)
{
  if (NULL == head)
    return;

  if (head->client == client)
  {
    GNUNET_CONNECTION_notify_transmit_ready_cancel (server_notify);
    server_notify =
        GNUNET_SERVER_notify_transmit_ready (head->next->client,
                                             ntohs (head->next->pkt.hdr.size),
                                             GNUNET_TIME_UNIT_FOREVER_REL,
                                             &send_answer, NULL);
  }

  struct answer_packet_list *element = head;

  while (element != NULL)
  {
    if (element->client == client)
    {
      GNUNET_SERVER_client_drop (client);
      GNUNET_CONTAINER_DLL_remove (head, tail, element);
      struct answer_packet_list *t = element;

      element = element->next;
      GNUNET_free (t);
    }
    else
      element = element->next;
  }
}

/**
 * Hijack all outgoing DNS-Traffic but for traffic leaving "our" port.
 */
static void
hijack (void *cls GNUNET_UNUSED, const struct GNUNET_SCHEDULER_TaskContext *tc)
{
  if (0 != (tc->reason & GNUNET_SCHEDULER_REASON_SHUTDOWN))
    return;

  if (0 == dnsoutport)
  {
    GNUNET_log (GNUNET_ERROR_TYPE_INFO,
                "Delaying the hijacking, port is still %d!\n", dnsoutport);
    GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_UNIT_SECONDS, &hijack, NULL);
    return;
  }

  char port_s[6];
  char *virt_dns;
  struct GNUNET_OS_Process *proc;

  if (GNUNET_SYSERR ==
      GNUNET_CONFIGURATION_get_value_string (cfg, "vpn", "VIRTDNS", &virt_dns))
  {
    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
                "No entry 'VIRTDNS' in configuration!\n");
    exit (1);
  }

  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Hijacking, port is %d\n", dnsoutport);
  snprintf (port_s, 6, "%d", dnsoutport);
  if (NULL !=
      (proc =
       GNUNET_OS_start_process (NULL, NULL, "gnunet-helper-hijack-dns",
                                "gnunet-hijack-dns", port_s, virt_dns, NULL)))
  {
    GNUNET_break (GNUNET_OK == GNUNET_OS_process_wait (proc));
    GNUNET_OS_process_close (proc);
  }
  GNUNET_free (virt_dns);
}

static void *
new_tunnel (void *cls GNUNET_UNUSED, struct GNUNET_MESH_Tunnel *tunnel,
            const struct GNUNET_PeerIdentity *initiator GNUNET_UNUSED,
            const struct GNUNET_ATS_Information *ats GNUNET_UNUSED)
{
  struct tunnel_state *s = GNUNET_malloc (sizeof *s);

  s->head = NULL;
  s->tail = NULL;
  s->th = NULL;
  return s;
}

static void
clean_tunnel (void *cls GNUNET_UNUSED, const struct GNUNET_MESH_Tunnel *tunnel,
              void *tunnel_ctx)
{
  GNUNET_free (tunnel_ctx);
}

/**
 * Delete the hijacking-routes
 */
static void
unhijack (unsigned short port)
{
  char port_s[6];
  char *virt_dns;
  struct GNUNET_OS_Process *proc;

  if (GNUNET_SYSERR ==
      GNUNET_CONFIGURATION_get_value_string (cfg, "vpn", "VIRTDNS", &virt_dns))
  {
    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
                "No entry 'VIRTDNS' in configuration!\n");
    exit (1);
  }

  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "unHijacking, port is %d\n", port);
  snprintf (port_s, 6, "%d", port);
  if (NULL !=
      (proc =
       GNUNET_OS_start_process (NULL, NULL, "gnunet-helper-hijack-dns",
                                "gnunet-hijack-dns", "-d", port_s, virt_dns,
                                NULL)))
  {
    GNUNET_break (GNUNET_OK == GNUNET_OS_process_wait (proc));
    GNUNET_OS_process_close (proc);
  }
  GNUNET_free (virt_dns);
}

/**
 * Send the DNS-Response to the client. Gets called via the notify_transmit_ready-
 * system.
 */
static size_t
send_answer (void *cls, size_t size, void *buf)
{
  server_notify = NULL;
  struct answer_packet_list *query = head;
  size_t len = ntohs (query->pkt.hdr.size);

  GNUNET_assert (len <= size);

  memcpy (buf, &query->pkt.hdr, len);

  GNUNET_CONTAINER_DLL_remove (head, tail, query);

  /* When more data is to be sent, reschedule */
  if (head != NULL)
    server_notify =
        GNUNET_SERVER_notify_transmit_ready (head->client,
                                             ntohs (head->pkt.hdr.size),
                                             GNUNET_TIME_UNIT_FOREVER_REL,
                                             &send_answer, NULL);

  GNUNET_SERVER_client_drop (query->client);
  GNUNET_free (query);
  return len;
}

struct tunnel_cls
{
  struct GNUNET_MESH_Tunnel *tunnel GNUNET_PACKED;
  struct GNUNET_MessageHeader hdr;
  struct dns_pkt dns;
};

struct tunnel_cls *remote_pending[UINT16_MAX];

static size_t
mesh_send_response (void *cls, size_t size, void *buf)
{
  GNUNET_assert (size >= sizeof (struct GNUNET_MessageHeader));
  struct GNUNET_MessageHeader *hdr = buf;
  uint32_t *sz = cls;
  struct GNUNET_MESH_Tunnel **tunnel = (struct GNUNET_MESH_Tunnel **) (sz + 1);
  struct dns_pkt *dns = (struct dns_pkt *) (tunnel + 1);

  GNUNET_MESH_tunnel_set_data (*tunnel, NULL);

  hdr->type = htons (GNUNET_MESSAGE_TYPE_VPN_REMOTE_ANSWER_DNS);
  hdr->size = htons (*sz + sizeof (struct GNUNET_MessageHeader));

  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
              "Sending response, size=%d, sz=%d, sz+hdr=%d\n", size, *sz,
              *sz + sizeof (struct GNUNET_MessageHeader));

  GNUNET_assert (size >= (*sz + sizeof (struct GNUNET_MessageHeader)));

  memcpy (hdr + 1, dns, *sz);
  struct tunnel_state *s = GNUNET_MESH_tunnel_get_data (*tunnel);

  if (NULL != s->head)
  {
    struct tunnel_notify_queue *element = s->head;
    struct tunnel_notify_queue *head = s->head;
    struct tunnel_notify_queue *tail = s->tail;

    GNUNET_CONTAINER_DLL_remove (head, tail, element);

    s->th =
        GNUNET_MESH_notify_transmit_ready (*tunnel, GNUNET_NO, 42,
                                           GNUNET_TIME_relative_divide
                                           (GNUNET_CONSTANTS_MAX_CORK_DELAY, 2),
                                           (const struct GNUNET_PeerIdentity *)
                                           NULL, element->len, element->cb,
                                           element->cls);
  }

  GNUNET_free (cls);

  return ntohs (hdr->size);
}

static size_t
mesh_send (void *cls, size_t size, void *buf)
{
  struct tunnel_cls *cls_ = (struct tunnel_cls *) cls;

  GNUNET_MESH_tunnel_set_data (cls_->tunnel, NULL);

  GNUNET_assert (cls_->hdr.size <= size);

  size = cls_->hdr.size;
  cls_->hdr.size = htons (cls_->hdr.size);

  memcpy (buf, &cls_->hdr, size);

  struct tunnel_state *s = GNUNET_MESH_tunnel_get_data (cls_->tunnel);

  if (NULL != s->head)
  {
    struct tunnel_notify_queue *element = s->head;
    struct tunnel_notify_queue *head = s->head;
    struct tunnel_notify_queue *tail = s->tail;;

    GNUNET_CONTAINER_DLL_remove (head, tail, element);

    s->th =
        GNUNET_MESH_notify_transmit_ready (cls_->tunnel, GNUNET_NO, 42,
                                           GNUNET_TIME_relative_divide
                                           (GNUNET_CONSTANTS_MAX_CORK_DELAY, 2),
                                           (const struct GNUNET_PeerIdentity *)
                                           NULL, element->len, element->cb,
                                           element->cls);

    GNUNET_free (element);
  }

  return size;
}


void
mesh_connect (void *cls, const struct GNUNET_PeerIdentity *peer,
              const struct GNUNET_ATS_Information *atsi GNUNET_UNUSED)
{
  if (NULL == peer)
    return;
  struct tunnel_cls *cls_ = (struct tunnel_cls *) cls;

  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
              "Connected to peer %s, %x, sending query with id %d\n",
              GNUNET_i2s (peer), peer, ntohs (cls_->dns.s.id));

  struct tunnel_state *s = GNUNET_MESH_tunnel_get_data (cls_->tunnel);

  if (NULL == s->head)
  {
    s->th =
        GNUNET_MESH_notify_transmit_ready (cls_->tunnel, GNUNET_YES, 42,
                                           GNUNET_TIME_UNIT_MINUTES, NULL,
                                           cls_->hdr.size, mesh_send, cls);

  }
  else
  {
    struct tunnel_notify_queue *head = s->head;
    struct tunnel_notify_queue *tail = s->tail;

    struct tunnel_notify_queue *element =
        GNUNET_malloc (sizeof (struct tunnel_notify_queue));
    element->cls = cls;
    element->len = cls_->hdr.size;
    element->cb = mesh_send;

    GNUNET_CONTAINER_DLL_insert_tail (head, tail, element);
  }
}


static void
send_mesh_query (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
{
  if (0 != (tc->reason & GNUNET_SCHEDULER_REASON_SHUTDOWN))
    return;

  struct tunnel_cls *cls_ = (struct tunnel_cls *) cls;

  struct tunnel_state *s = GNUNET_malloc (sizeof *s);

  s->head = NULL;
  s->tail = NULL;
  s->th = NULL;

  cls_->tunnel =
      GNUNET_MESH_tunnel_create (mesh_handle, s, mesh_connect, NULL, cls_);

  GNUNET_MESH_peer_request_connect_by_type (cls_->tunnel,
                                            GNUNET_APPLICATION_TYPE_INTERNET_RESOLVER);

  remote_pending[cls_->dns.s.id] = cls_;
}

static int
receive_mesh_query (void *cls GNUNET_UNUSED, struct GNUNET_MESH_Tunnel *tunnel,
                    void **ctx GNUNET_UNUSED,
                    const struct GNUNET_PeerIdentity *sender GNUNET_UNUSED,
                    const struct GNUNET_MessageHeader *message,
                    const struct GNUNET_ATS_Information *atsi GNUNET_UNUSED)
{
  struct dns_pkt *dns = (struct dns_pkt *) (message + 1);

  struct sockaddr_in dest;

  struct dns_pkt_parsed *pdns = parse_dns_packet (dns);

  memset (&dest, 0, sizeof dest);
  dest.sin_port = htons (53);
  char *dns_resolver;

  if (GNUNET_OK !=
      GNUNET_CONFIGURATION_get_value_string (cfg, "dns", "EXTERNAL_DNS",
                                             &dns_resolver) ||
      1 != inet_pton (AF_INET, dns_resolver, &dest.sin_addr))
    inet_pton (AF_INET, "8.8.8.8", &dest.sin_addr);

  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Querying for remote, id=%d\n",
              ntohs (dns->s.id));
  query_states[dns->s.id].tunnel = tunnel;
  query_states[dns->s.id].valid = GNUNET_YES;

  int i;

  for (i = 0; i < ntohs (pdns->s.qdcount); i++)
  {
    if (pdns->queries[i]->qtype == htons (28) ||
        pdns->queries[i]->qtype == htons (1))
    {
      query_states[dns->s.id].qtype = pdns->queries[i]->qtype;
      break;
    }
  }
  free_parsed_dns_packet (pdns);

  GNUNET_NETWORK_socket_sendto (dnsout, dns,
                                ntohs (message->size) -
                                sizeof (struct GNUNET_MessageHeader),
                                (struct sockaddr *) &dest, sizeof dest);

  return GNUNET_SYSERR;
}

static int
receive_mesh_answer (void *cls GNUNET_UNUSED, struct GNUNET_MESH_Tunnel *tunnel,
                     void **ctx GNUNET_UNUSED,
                     const struct GNUNET_PeerIdentity *sender,
                     const struct GNUNET_MessageHeader *message,
                     const struct GNUNET_ATS_Information *atsi GNUNET_UNUSED)
{
  /* TODo: size check */
  struct dns_pkt *dns = (struct dns_pkt *) (message + 1);

  /* They sent us a packet we were not waiting for */
  if (remote_pending[dns->s.id] == NULL ||
      remote_pending[dns->s.id]->tunnel != tunnel)
    return GNUNET_OK;

  GNUNET_free (remote_pending[dns->s.id]);
  remote_pending[dns->s.id] = NULL;

  if (query_states[dns->s.id].valid != GNUNET_YES)
    return GNUNET_SYSERR;
  query_states[dns->s.id].valid = GNUNET_NO;

  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
              "Received answer from peer %s, dns-id %d\n", GNUNET_i2s (sender),
              ntohs (dns->s.id));

  size_t len = sizeof (struct answer_packet) - 1 + sizeof (struct dns_static) + query_states[dns->s.id].namelen + sizeof (struct dns_query_line) + 2    /* To hold the pointer (as defined in RFC1035) to the name */
      + sizeof (struct dns_record_line) - 1 + 16;       /* To hold the IPv6-Address */

  struct answer_packet_list *answer =
      GNUNET_malloc (len + sizeof (struct answer_packet_list) -
                     sizeof (struct answer_packet));

  answer->pkt.hdr.type = htons (GNUNET_MESSAGE_TYPE_VPN_DNS_LOCAL_RESPONSE_DNS);
  answer->pkt.hdr.size = htons (len);

  struct dns_pkt_parsed *pdns = parse_dns_packet (dns);

  if (ntohs (pdns->s.ancount) < 1)
  {
    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Answer only contains %d answers.\n",
                ntohs (pdns->s.ancount));
    free_parsed_dns_packet (pdns);
    GNUNET_free (answer);
    return GNUNET_OK;
  }

  int i = 0;

  while (i < ntohs (pdns->s.ancount) && ntohs (pdns->answers[i]->type) != 28 &&
         ntohs (pdns->answers[i]->type) != 1)
  {
    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Answer contains %d.\n",
                ntohs (pdns->answers[i]->type));
    i++;
  }

  if (i >= ntohs (pdns->s.ancount))
  {
    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
                "Answer does not contain any usable answers.\n");
    free_parsed_dns_packet (pdns);
    GNUNET_free (answer);
    return GNUNET_OK;
  }

  answer->pkt.addrsize = ntohs (pdns->answers[i]->data_len);
  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "The first answer has the addrlen %d\n",
              answer->pkt.addrsize);
  memcpy (answer->pkt.addr, pdns->answers[i]->data,
          ntohs (pdns->answers[i]->data_len));

  memcpy (answer->pkt.from, query_states[dns->s.id].remote_ip,
          query_states[dns->s.id].addrlen);
  memcpy (answer->pkt.to, query_states[dns->s.id].local_ip,
          query_states[dns->s.id].addrlen);
  answer->pkt.addrlen = query_states[dns->s.id].addrlen;
  answer->pkt.dst_port = query_states[dns->s.id].local_port;

  struct dns_pkt *dpkt = (struct dns_pkt *) answer->pkt.data;

  dpkt->s.id = dns->s.id;
  dpkt->s.aa = 1;
  dpkt->s.qr = 1;
  dpkt->s.ra = 1;
  dpkt->s.qdcount = htons (1);
  dpkt->s.ancount = htons (1);

  memcpy (dpkt->data, query_states[dns->s.id].name,
          query_states[dns->s.id].namelen);
  GNUNET_free (query_states[dns->s.id].name);
  query_states[dns->s.id].name = NULL;

  struct dns_query_line *dque =
      (struct dns_query_line *) (dpkt->data +
                                 (query_states[dns->s.id].namelen));

  struct dns_record_line *drec_data =
      (struct dns_record_line *) (dpkt->data +
                                  (query_states[dns->s.id].namelen) +
                                  sizeof (struct dns_query_line) + 2);
  if (htons (28) == query_states[dns->s.id].qtype)
  {
    answer->pkt.subtype = GNUNET_DNS_ANSWER_TYPE_REMOTE_AAAA;
    dque->type = htons (28);    /* AAAA */
    drec_data->type = htons (28);       /* AAAA */
    drec_data->data_len = htons (16);
  }
  else if (htons (1) == query_states[dns->s.id].qtype)
  {
    answer->pkt.subtype = GNUNET_DNS_ANSWER_TYPE_REMOTE_A;
    dque->type = htons (1);     /* A */
    drec_data->type = htons (1);        /* A */
    drec_data->data_len = htons (4);
  }
  else
  {
    GNUNET_log (GNUNET_ERROR_TYPE_ERROR, "dns-answer with pending qtype = %d\n",
                query_states[dns->s.id].qtype);
    GNUNET_assert (0);
  }
  dque->class = htons (1);      /* IN */

  char *anname =
      (char *) (dpkt->data + (query_states[dns->s.id].namelen) +
                sizeof (struct dns_query_line));
  memcpy (anname, "\xc0\x0c", 2);
  drec_data->class = htons (1); /* IN */

  drec_data->ttl = pdns->answers[i]->ttl;

  /* Calculate at which offset in the packet the IPv6-Address belongs, it is
   * filled in by the daemon-vpn */
  answer->pkt.addroffset =
      htons ((unsigned short) ((unsigned long) (&drec_data->data) -
                               (unsigned long) (&answer->pkt)));

  GNUNET_CONTAINER_DLL_insert_after (head, tail, tail, answer);
  answer->client = query_states[dns->s.id].client;

  if (server_notify == NULL)
    server_notify =
        GNUNET_SERVER_notify_transmit_ready (query_states[dns->s.id].client,
                                             len, GNUNET_TIME_UNIT_FOREVER_REL,
                                             &send_answer, NULL);

  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
              "Sent answer of length %d on to client, addroffset = %d\n", len,
              answer->pkt.addroffset);

  free_parsed_dns_packet (pdns);
  return GNUNET_OK;
}


static void
send_rev_query (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
{
  if (0 != (tc->reason & GNUNET_SCHEDULER_REASON_SHUTDOWN))
    return;

  struct dns_pkt_parsed *pdns = (struct dns_pkt_parsed *) cls;

  unsigned short id = pdns->s.id;

  free_parsed_dns_packet (pdns);

  if (query_states[id].valid != GNUNET_YES)
    return;
  query_states[id].valid = GNUNET_NO;

  GNUNET_assert (query_states[id].namelen == 74);

  size_t len = sizeof (struct answer_packet) - 1 + sizeof (struct dns_static) + 74      /* this is the length of a reverse ipv6-lookup */
      + sizeof (struct dns_query_line) + 2      /* To hold the pointer (as defined in RFC1035) to the name */
      + sizeof (struct dns_record_line) - 1 -
      2 /* We do not know the lenght of the answer yet */ ;

  struct answer_packet_list *answer =
      GNUNET_malloc (len + sizeof (struct answer_packet_list) -
                     sizeof (struct answer_packet));

  answer->pkt.hdr.type = htons (GNUNET_MESSAGE_TYPE_VPN_DNS_LOCAL_RESPONSE_DNS);
  answer->pkt.hdr.size = htons (len);
  answer->pkt.subtype = GNUNET_DNS_ANSWER_TYPE_REV;

  memcpy (answer->pkt.from, query_states[id].remote_ip,
          query_states[id].addrlen);
  memcpy (answer->pkt.to, query_states[id].local_ip, query_states[id].addrlen);

  answer->pkt.dst_port = query_states[id].local_port;

  struct dns_pkt *dpkt = (struct dns_pkt *) answer->pkt.data;

  dpkt->s.id = id;
  dpkt->s.aa = 1;
  dpkt->s.qr = 1;
  dpkt->s.ra = 1;
  dpkt->s.qdcount = htons (1);
  dpkt->s.ancount = htons (1);

  memcpy (dpkt->data, query_states[id].name, query_states[id].namelen);
  GNUNET_free (query_states[id].name);
  query_states[id].name = NULL;

  struct dns_query_line *dque =
      (struct dns_query_line *) (dpkt->data + (query_states[id].namelen));
  dque->type = htons (12);      /* PTR */
  dque->class = htons (1);      /* IN */

  char *anname =
      (char *) (dpkt->data + (query_states[id].namelen) +
                sizeof (struct dns_query_line));
  memcpy (anname, "\xc0\x0c", 2);

  struct dns_record_line *drec_data =
      (struct dns_record_line *) (dpkt->data + (query_states[id].namelen) +
                                  sizeof (struct dns_query_line) + 2);
  drec_data->type = htons (12); /* AAAA */
  drec_data->class = htons (1); /* IN */
  /* FIXME: read the TTL from block:
   * GNUNET_TIME_absolute_get_remaining(rec->expiration_time)
   *
   * But how to get the seconds out of this?
   */
  drec_data->ttl = htonl (3600);

  /* Calculate at which offset in the packet the length of the name and the
   * name, it is filled in by the daemon-vpn */
  answer->pkt.addroffset =
      htons ((unsigned short) ((unsigned long) (&drec_data->data_len) -
                               (unsigned long) (&answer->pkt)));

  GNUNET_CONTAINER_DLL_insert_after (head, tail, tail, answer);
  answer->client = query_states[id].client;

  if (server_notify == NULL)
    server_notify =
        GNUNET_SERVER_notify_transmit_ready (query_states[id].client, len,
                                             GNUNET_TIME_UNIT_FOREVER_REL,
                                             &send_answer, NULL);
}

/**
 * Receive a block from the dht.
 */
static void
receive_dht (void *cls, struct GNUNET_TIME_Absolute exp GNUNET_UNUSED,
             const GNUNET_HashCode * key GNUNET_UNUSED,
             const struct GNUNET_PeerIdentity *get_path GNUNET_UNUSED,
             unsigned int get_path_length GNUNET_UNUSED,
             const struct GNUNET_PeerIdentity *put_path GNUNET_UNUSED,
             unsigned int put_path_length GNUNET_UNUSED,
             enum GNUNET_BLOCK_Type type, size_t size, const void *data)
{

  unsigned short id = ((struct receive_dht_cls *) cls)->id;
  struct GNUNET_DHT_GetHandle *handle =
      ((struct receive_dht_cls *) cls)->handle;
  GNUNET_free (cls);

  GNUNET_DHT_get_stop (handle);

  GNUNET_assert (type == GNUNET_BLOCK_TYPE_DNS);

  /* If no query with this id is pending, ignore the block */
  if (query_states[id].valid != GNUNET_YES)
    return;
  query_states[id].valid = GNUNET_NO;

  const struct GNUNET_DNS_Record *rec = data;

  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
              "Got block of size %d, peer: %08x, desc: %08x\n", size,
              *((unsigned int *) &rec->peer),
              *((unsigned int *) &rec->service_descriptor));

  size_t len = sizeof (struct answer_packet) - 1 + sizeof (struct dns_static) + query_states[id].namelen + sizeof (struct dns_query_line) + 2   /* To hold the pointer (as defined in RFC1035) to the name */
      + sizeof (struct dns_record_line) - 1 + 16;       /* To hold the IPv6-Address */

  struct answer_packet_list *answer =
      GNUNET_malloc (len + sizeof (struct answer_packet_list) -
                     sizeof (struct answer_packet));

  answer->pkt.hdr.type = htons (GNUNET_MESSAGE_TYPE_VPN_DNS_LOCAL_RESPONSE_DNS);
  answer->pkt.hdr.size = htons (len);
  answer->pkt.subtype = GNUNET_DNS_ANSWER_TYPE_SERVICE;
  answer->client = query_states[id].client;

  GNUNET_CRYPTO_hash (&rec->peer,
                      sizeof (struct GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded),
                      &answer->pkt.service_descr.peer);

  memcpy (&answer->pkt.service_descr.service_descriptor,
          &rec->service_descriptor, sizeof (GNUNET_HashCode));
  memcpy (&answer->pkt.service_descr.service_type, &rec->service_type,
          sizeof (answer->pkt.service_descr.service_type));
  memcpy (&answer->pkt.service_descr.ports, &rec->ports,
          sizeof (answer->pkt.service_descr.ports));

  memcpy (answer->pkt.from, query_states[id].remote_ip,
          query_states[id].addrlen);
  memcpy (answer->pkt.to, query_states[id].local_ip, query_states[id].addrlen);
  answer->pkt.addrlen = query_states[id].addrlen;

  answer->pkt.dst_port = query_states[id].local_port;

  struct dns_pkt *dpkt = (struct dns_pkt *) answer->pkt.data;

  dpkt->s.id = id;
  dpkt->s.aa = 1;
  dpkt->s.qr = 1;
  dpkt->s.ra = 1;
  dpkt->s.qdcount = htons (1);
  dpkt->s.ancount = htons (1);

  memcpy (dpkt->data, query_states[id].name, query_states[id].namelen);
  GNUNET_free (query_states[id].name);
  query_states[id].name = NULL;

  struct dns_query_line *dque =
      (struct dns_query_line *) (dpkt->data + (query_states[id].namelen));
  dque->type = htons (28);      /* AAAA */
  dque->class = htons (1);      /* IN */

  char *anname =
      (char *) (dpkt->data + (query_states[id].namelen) +
                sizeof (struct dns_query_line));
  memcpy (anname, "\xc0\x0c", 2);

  struct dns_record_line *drec_data =
      (struct dns_record_line *) (dpkt->data + (query_states[id].namelen) +
                                  sizeof (struct dns_query_line) + 2);
  drec_data->type = htons (28); /* AAAA */
  drec_data->class = htons (1); /* IN */

  /* FIXME: read the TTL from block:
   * GNUNET_TIME_absolute_get_remaining(rec->expiration_time)
   *
   * But how to get the seconds out of this?
   */
  drec_data->ttl = htonl (3600);
  drec_data->data_len = htons (16);

  /* Calculate at which offset in the packet the IPv6-Address belongs, it is
   * filled in by the daemon-vpn */
  answer->pkt.addroffset =
      htons ((unsigned short) ((unsigned long) (&drec_data->data) -
                               (unsigned long) (&answer->pkt)));

  GNUNET_CONTAINER_DLL_insert_after (head, tail, tail, answer);

  if (server_notify == NULL)
    server_notify =
        GNUNET_SERVER_notify_transmit_ready (answer->client, len,
                                             GNUNET_TIME_UNIT_FOREVER_REL,
                                             &send_answer, NULL);
}

/**
 * This receives a GNUNET_MESSAGE_TYPE_REHIJACK and rehijacks the DNS
 */
static void
rehijack (void *cls GNUNET_UNUSED, struct GNUNET_SERVER_Client *client,
          const struct GNUNET_MessageHeader *message GNUNET_UNUSED)
{
  unhijack (dnsoutport);
  GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_UNIT_SECONDS, &hijack, NULL);

  GNUNET_SERVER_receive_done (client, GNUNET_OK);
}

/**
 * This receives the dns-payload from the daemon-vpn and sends it on over the udp-socket
 */
static void
receive_query (void *cls GNUNET_UNUSED, struct GNUNET_SERVER_Client *client,
               const struct GNUNET_MessageHeader *message)
{
  struct query_packet *pkt = (struct query_packet *) message;
  struct dns_pkt *dns = (struct dns_pkt *) pkt->data;
  struct dns_pkt_parsed *pdns = parse_dns_packet (dns);

  query_states[dns->s.id].valid = GNUNET_YES;
  query_states[dns->s.id].client = client;
  GNUNET_SERVER_client_keep (client);
  memcpy (query_states[dns->s.id].local_ip, pkt->orig_from, pkt->addrlen);
  query_states[dns->s.id].addrlen = pkt->addrlen;
  query_states[dns->s.id].local_port = pkt->src_port;
  memcpy (query_states[dns->s.id].remote_ip, pkt->orig_to, pkt->addrlen);
  query_states[dns->s.id].namelen = strlen ((char *) dns->data) + 1;
  if (query_states[dns->s.id].name != NULL)
    GNUNET_free (query_states[dns->s.id].name);
  query_states[dns->s.id].name =
      GNUNET_malloc (query_states[dns->s.id].namelen);
  memcpy (query_states[dns->s.id].name, dns->data,
          query_states[dns->s.id].namelen);

  int i;

  for (i = 0; i < ntohs (pdns->s.qdcount); i++)
  {
    if (pdns->queries[i]->qtype == htons (28) ||
        pdns->queries[i]->qtype == htons (1))
    {
      query_states[dns->s.id].qtype = pdns->queries[i]->qtype;
      break;
    }
  }

  /* The query is for a .gnunet-address */
  if (pdns->queries[0]->namelen > 9 &&
      0 == strncmp (pdns->queries[0]->name + (pdns->queries[0]->namelen - 9),
                    ".gnunet.", 9))
  {
    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Query for .gnunet!\n");
    GNUNET_HashCode key;

    GNUNET_CRYPTO_hash (pdns->queries[0]->name, pdns->queries[0]->namelen,
                        &key);

    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Getting with key %08x, len is %d\n",
                *((unsigned int *) &key), pdns->queries[0]->namelen);

    struct receive_dht_cls *cls =
        GNUNET_malloc (sizeof (struct receive_dht_cls));
    cls->id = dns->s.id;

    cls->handle =
        GNUNET_DHT_get_start (dht, GNUNET_TIME_UNIT_MINUTES,
                              GNUNET_BLOCK_TYPE_DNS, &key,
                              5 /* DEFAULT_GET_REPLICATION */ ,
                              GNUNET_DHT_RO_NONE, NULL, 0, &receive_dht, cls);

    goto outfree;
  }

  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Query for '%s'; namelen=%d\n",
              pdns->queries[0]->name, pdns->queries[0]->namelen);

  /* This is a PTR-Query. Check if it is for "our" network */
  if (htons (pdns->queries[0]->qtype) == 12 && 74 == pdns->queries[0]->namelen)
  {
    char *ipv6addr;
    char ipv6[16];
    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.";
    unsigned int i;
    unsigned long long ipv6prefix;
    unsigned int comparelen;

    GNUNET_assert (GNUNET_OK ==
                   GNUNET_CONFIGURATION_get_value_string (cfg, "vpn",
                                                          "IPV6ADDR",
                                                          &ipv6addr));
    inet_pton (AF_INET6, ipv6addr, ipv6);
    GNUNET_free (ipv6addr);

    GNUNET_assert (GNUNET_OK ==
                   GNUNET_CONFIGURATION_get_value_number (cfg, "vpn",
                                                          "IPV6PREFIX",
                                                          &ipv6prefix));
    GNUNET_assert (ipv6prefix < 127);
    ipv6prefix = (ipv6prefix + 7) / 8;

    for (i = ipv6prefix; i < 16; i++)
      ipv6[i] = 0;

    for (i = 0; i < 16; i++)
    {
      unsigned char c1 = ipv6[i] >> 4;
      unsigned char c2 = ipv6[i] & 0xf;

      if (c1 <= 9)
        ipv6rev[62 - (4 * i)] = c1 + '0';
      else
        ipv6rev[62 - (4 * i)] = c1 + 87;        /* 87 is the difference between 'a' and 10 */

      if (c2 <= 9)
        ipv6rev[62 - ((4 * i) + 2)] = c2 + '0';
      else
        ipv6rev[62 - ((4 * i) + 2)] = c2 + 87;
    }
    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "My network is %s'.\n", ipv6rev);
    comparelen = 10 + 4 * ipv6prefix;
    if (0 ==
        strncmp (pdns->queries[0]->name +
                 (pdns->queries[0]->namelen - comparelen),
                 ipv6rev + (74 - comparelen), comparelen))
    {
      GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Reverse-Query for .gnunet!\n");

      GNUNET_SCHEDULER_add_now (send_rev_query, pdns);

      goto out;
    }
  }

  unsigned char virt_dns_bytes[16];

  if (pkt->addrlen == 4)
  {
    char *virt_dns;

    if (GNUNET_SYSERR ==
        GNUNET_CONFIGURATION_get_value_string (cfg, "vpn", "VIRTDNS",
                                               &virt_dns))
    {
      GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
                  "No entry 'VIRTDNS' in configuration!\n");
      exit (1);
    }

    if (1 != inet_pton (AF_INET, virt_dns, &virt_dns_bytes))
    {
      GNUNET_log (GNUNET_ERROR_TYPE_ERROR, "Error parsing 'VIRTDNS': %s; %m!\n",
                  virt_dns);
      exit (1);
    }

    GNUNET_free (virt_dns);
  }
  else if (pkt->addrlen == 16)
  {
    char *virt_dns;

    if (GNUNET_SYSERR ==
        GNUNET_CONFIGURATION_get_value_string (cfg, "vpn", "VIRTDNS6",
                                               &virt_dns))
    {
      GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
                  "No entry 'VIRTDNS6' in configuration!\n");
      exit (1);
    }

    if (1 != inet_pton (AF_INET6, virt_dns, &virt_dns_bytes))
    {
      GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
                  "Error parsing 'VIRTDNS6': %s; %m!\n", virt_dns);
      exit (1);
    }

    GNUNET_free (virt_dns);
  }
  else
  {
    GNUNET_assert (0);
  }

  if (memcmp (virt_dns_bytes, pkt->orig_to, pkt->addrlen) == 0)
  {
    /* This is a packet that was sent directly to the virtual dns-server
     *
     * This means we have to send this query over gnunet
     */

    size_t size =
        sizeof (struct GNUNET_MESH_Tunnel *) +
        sizeof (struct GNUNET_MessageHeader) + (ntohs (message->size) -
                                                sizeof (struct query_packet) +
                                                1);
    struct tunnel_cls *cls_ = GNUNET_malloc (size);

    cls_->hdr.size = size - sizeof (struct GNUNET_MESH_Tunnel *);

    cls_->hdr.type = ntohs (GNUNET_MESSAGE_TYPE_VPN_REMOTE_QUERY_DNS);
    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "size: %d\n", size);

    memcpy (&cls_->dns, dns,
            cls_->hdr.size - sizeof (struct GNUNET_MessageHeader));
    GNUNET_SCHEDULER_add_now (send_mesh_query, cls_);

    if (ntohs (pdns->s.qdcount) == 1)
    {
      if (ntohs (pdns->queries[0]->qtype) == 1)
        pdns->queries[0]->qtype = htons (28);
      else if (ntohs (pdns->queries[0]->qtype) == 28)
        pdns->queries[0]->qtype = htons (1);
      else
      {
        GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "not sending second packet\n");
        goto outfree;
      }
      GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "sending second packet\n");
      struct dns_pkt *rdns = unparse_dns_packet (pdns);
      size_t size =
          sizeof (struct GNUNET_MESH_Tunnel *) +
          sizeof (struct GNUNET_MessageHeader) + (ntohs (message->size) -
                                                  sizeof (struct query_packet) +
                                                  1);
      struct tunnel_cls *cls_ = GNUNET_malloc (size);

      cls_->hdr.size = size - sizeof (struct GNUNET_MESH_Tunnel *);

      cls_->hdr.type = ntohs (GNUNET_MESSAGE_TYPE_VPN_REMOTE_QUERY_DNS);
      GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "size: %d\n", size);

      memcpy (&cls_->dns, rdns,
              cls_->hdr.size - sizeof (struct GNUNET_MessageHeader));
      GNUNET_SCHEDULER_add_now (send_mesh_query, cls_);
      GNUNET_free (rdns);
    }

    goto outfree;
  }


  /* The query should be sent to the network */
  if (pkt->addrlen == 4)
  {
    struct sockaddr_in dest;

    memset (&dest, 0, sizeof dest);
    dest.sin_port = htons (53);
    memcpy (&dest.sin_addr.s_addr, pkt->orig_to, pkt->addrlen);

    GNUNET_NETWORK_socket_sendto (dnsout, dns,
                                  ntohs (pkt->hdr.size) -
                                  sizeof (struct query_packet) + 1,
                                  (struct sockaddr *) &dest, sizeof dest);
  }
  else if (pkt->addrlen == 16)
  {
    struct sockaddr_in6 dest;

    memset (&dest, 0, sizeof dest);
    dest.sin6_port = htons (53);
    memcpy (&dest.sin6_addr, pkt->orig_to, pkt->addrlen);

    GNUNET_NETWORK_socket_sendto (dnsout6, dns,
                                  ntohs (pkt->hdr.size) -
                                  sizeof (struct query_packet) + 1,
                                  (struct sockaddr *) &dest, sizeof dest);
  }

outfree:
  free_parsed_dns_packet (pdns);
  pdns = NULL;
out:
  GNUNET_SERVER_receive_done (client, GNUNET_OK);
}

static void
read_response (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc);

static void
read_response6 (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc);

static int
open_port6 ()
{
  struct sockaddr_in6 addr;

  dnsout6 = GNUNET_NETWORK_socket_create (AF_INET6, SOCK_DGRAM, 0);
  if (dnsout6 == NULL)
  {
    GNUNET_log (GNUNET_ERROR_TYPE_ERROR, "Could not create socket: %m\n");
    return GNUNET_SYSERR;
  }
  memset (&addr, 0, sizeof (struct sockaddr_in6));

  addr.sin6_family = AF_INET6;
  int err = GNUNET_NETWORK_socket_bind (dnsout6,
                                        (struct sockaddr *) &addr,
                                        sizeof (struct sockaddr_in6));

  if (err != GNUNET_OK)
  {
    GNUNET_log (GNUNET_ERROR_TYPE_ERROR, "Could not bind a port: %m\n");
    return GNUNET_SYSERR;
  }

  GNUNET_SCHEDULER_add_read_net (GNUNET_TIME_UNIT_FOREVER_REL, dnsout6,
                                 &read_response6, NULL);

  return GNUNET_YES;
}

static int
open_port ()
{
  struct sockaddr_in addr;

  dnsout = GNUNET_NETWORK_socket_create (AF_INET, SOCK_DGRAM, 0);
  if (dnsout == NULL)
    return GNUNET_SYSERR;
  memset (&addr, 0, sizeof (struct sockaddr_in));

  addr.sin_family = AF_INET;
  int err = GNUNET_NETWORK_socket_bind (dnsout,
                                        (struct sockaddr *) &addr,
                                        sizeof (struct sockaddr_in));

  if (err != GNUNET_OK)
  {
    GNUNET_log (GNUNET_ERROR_TYPE_ERROR, "Could not bind a port: %m\n");
    return GNUNET_SYSERR;
  }

  /* Read the port we bound to */
  socklen_t addrlen = sizeof (struct sockaddr_in);

  err =
      getsockname (GNUNET_NETWORK_get_fd (dnsout), (struct sockaddr *) &addr,
                   &addrlen);

  dnsoutport = htons (addr.sin_port);

  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Bound to port %d.\n", dnsoutport);

  GNUNET_SCHEDULER_add_read_net (GNUNET_TIME_UNIT_FOREVER_REL, dnsout,
                                 &read_response, NULL);

  return GNUNET_YES;
}

void
handle_response (struct dns_pkt *dns, struct sockaddr *addr, socklen_t addrlen,
                 int r);

/**
 * Read a response-packet of the UDP-Socket
 */
static void
read_response6 (void *cls GNUNET_UNUSED,
                const struct GNUNET_SCHEDULER_TaskContext *tc)
{
  struct sockaddr_in6 addr;
  socklen_t addrlen = sizeof (addr);
  int r;
  int len;

  if (tc->reason & GNUNET_SCHEDULER_REASON_SHUTDOWN)
    return;

  memset (&addr, 0, sizeof addr);

#ifndef MINGW
  if (0 != ioctl (GNUNET_NETWORK_get_fd (dnsout6), FIONREAD, &len))
  {
    (void) open_port6 ();
    return;
  }
#else
  /* port the code above? */
  len = 65536;
#endif

  unsigned char buf[len];
  struct dns_pkt *dns = (struct dns_pkt *) buf;

  r = GNUNET_NETWORK_socket_recvfrom (dnsout, buf, sizeof (buf),
                                      (struct sockaddr *) &addr, &addrlen);

  if (r < 0)
  {
    (void) open_port6 ();
    return;
  }

  struct sockaddr *addr_ = GNUNET_malloc (sizeof addr);

  memcpy (addr_, &addr, sizeof addr);
  handle_response (dns, addr_, 4, r);

  GNUNET_SCHEDULER_add_read_net (GNUNET_TIME_UNIT_FOREVER_REL, dnsout6,
                                 &read_response6, NULL);
}

/**
 * Read a response-packet of the UDP-Socket
 */
static void
read_response (void *cls GNUNET_UNUSED,
               const struct GNUNET_SCHEDULER_TaskContext *tc)
{
  struct sockaddr_in addr;
  socklen_t addrlen = sizeof (addr);
  int r;
  int len;

  if (tc->reason & GNUNET_SCHEDULER_REASON_SHUTDOWN)
    return;

  memset (&addr, 0, sizeof addr);

#ifndef MINGW
  if (0 != ioctl (GNUNET_NETWORK_get_fd (dnsout), FIONREAD, &len))
  {
    GNUNET_log_strerror (GNUNET_ERROR_TYPE_WARNING, "ioctl");
    unhijack (dnsoutport);
    if (GNUNET_YES == open_port ())
      GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_UNIT_SECONDS, &hijack, NULL);
    return;
  }
#else
  /* port the code above? */
  len = 65536;
#endif

  unsigned char buf[len];
  struct dns_pkt *dns = (struct dns_pkt *) buf;

  r = GNUNET_NETWORK_socket_recvfrom (dnsout, buf, sizeof (buf),
                                      (struct sockaddr *) &addr, &addrlen);

  if (r < 0)
  {
    GNUNET_log_strerror (GNUNET_ERROR_TYPE_WARNING, "recvfrom");
    unhijack (dnsoutport);
    if (GNUNET_YES == open_port ())
      GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_UNIT_SECONDS, &hijack, NULL);
    return;
  }

  struct sockaddr *addr_ = GNUNET_malloc (sizeof addr);

  memcpy (addr_, &addr, sizeof addr);
  handle_response (dns, addr_, 4, r);

  GNUNET_SCHEDULER_add_read_net (GNUNET_TIME_UNIT_FOREVER_REL, dnsout,
                                 &read_response, NULL);
}

void
handle_response (struct dns_pkt *dns, struct sockaddr *addr, socklen_t addrlen,
                 int r)
{
  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Answer to query %d\n",
              ntohs (dns->s.id));


  if (query_states[dns->s.id].valid == GNUNET_YES)
  {
    if (query_states[dns->s.id].tunnel != NULL)
    {
      GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
                  "Answer to query %d for a remote peer!\n", ntohs (dns->s.id));
      /* This response should go through a tunnel */
      uint32_t *c =
          GNUNET_malloc (4 + sizeof (struct GNUNET_MESH_Tunnel *) + r);
      *c = r;
      struct GNUNET_MESH_Tunnel **t = (struct GNUNET_MESH_Tunnel **) (c + 1);

      *t = query_states[dns->s.id].tunnel;
      memcpy (t + 1, dns, r);
      struct tunnel_state *s =
          GNUNET_MESH_tunnel_get_data (query_states[dns->s.id].tunnel);
      if (NULL == s->th)
      {
        s->th =
            GNUNET_MESH_notify_transmit_ready (query_states[dns->s.id].tunnel,
                                               GNUNET_YES, 32,
                                               GNUNET_TIME_UNIT_MINUTES, NULL,
                                               r +
                                               sizeof (struct
                                                       GNUNET_MessageHeader),
                                               mesh_send_response, c);
      }
      else
      {
        struct tunnel_notify_queue *element =
            GNUNET_malloc (sizeof (struct tunnel_notify_queue));
        element->cls = c;
        element->len = r + sizeof (struct GNUNET_MessageHeader);
        element->cb = mesh_send_response;

        GNUNET_CONTAINER_DLL_insert_tail (s->head, s->tail, element);
      }
    }
    else
    {
      query_states[dns->s.id].valid = GNUNET_NO;

      size_t len = sizeof (struct answer_packet) + r - 1;       /* 1 for the unsigned char data[1]; */
      struct answer_packet_list *answer =
          GNUNET_malloc (len + sizeof (struct answer_packet_list) -
                         (sizeof (struct answer_packet)));
      answer->pkt.hdr.type =
          htons (GNUNET_MESSAGE_TYPE_VPN_DNS_LOCAL_RESPONSE_DNS);
      answer->pkt.hdr.size = htons (len);
      answer->pkt.subtype = GNUNET_DNS_ANSWER_TYPE_IP;
      answer->pkt.addrlen = addrlen;
      if (addrlen == 16)
      {
        struct sockaddr_in6 *addr_ = (struct sockaddr_in6 *) addr;

        memcpy (answer->pkt.from, &addr_->sin6_addr, addrlen);
        memcpy (answer->pkt.to, query_states[dns->s.id].local_ip, addrlen);
      }
      else if (addrlen == 4)
      {
        struct sockaddr_in *addr_ = (struct sockaddr_in *) addr;

        memcpy (answer->pkt.from, &addr_->sin_addr.s_addr, addrlen);
        memcpy (answer->pkt.to, query_states[dns->s.id].local_ip, addrlen);
      }
      else
      {
        GNUNET_log (GNUNET_ERROR_TYPE_ERROR, "addrlen = %d\n", addrlen);
        GNUNET_assert (0);
      }
      GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "sending answer with addrlen = %d\n",
                  addrlen);
      answer->pkt.dst_port = query_states[dns->s.id].local_port;
      memcpy (answer->pkt.data, dns, r);
      answer->client = query_states[dns->s.id].client;

      GNUNET_CONTAINER_DLL_insert_after (head, tail, tail, answer);

      if (server_notify == NULL)
        server_notify =
            GNUNET_SERVER_notify_transmit_ready (query_states[dns->s.id].client,
                                                 len,
                                                 GNUNET_TIME_UNIT_FOREVER_REL,
                                                 &send_answer, NULL);
    }
  }
  GNUNET_free (addr);
}


/**
 * Task run during shutdown.
 *
 * @param cls unused
 * @param tc unused
 */
static void
cleanup_task (void *cls GNUNET_UNUSED,
              const struct GNUNET_SCHEDULER_TaskContext *tc)
{
  GNUNET_assert (0 != (tc->reason & GNUNET_SCHEDULER_REASON_SHUTDOWN));

  unhijack (dnsoutport);
  GNUNET_DHT_disconnect (dht);
  GNUNET_MESH_disconnect (mesh_handle);
}

/**
 * @brief Create a port-map from udp and tcp redirects
 *
 * @param udp_redirects
 * @param tcp_redirects
 *
 * @return
 */
static uint64_t
get_port_from_redirects (const char *udp_redirects, const char *tcp_redirects)
{
  uint64_t ret = 0;
  char *cpy, *hostname, *redirect;
  int local_port;
  unsigned int count = 0;

  cpy = NULL;
  if (NULL != udp_redirects)
  {
    cpy = GNUNET_strdup (udp_redirects);
    for (redirect = strtok (cpy, " "); redirect != NULL;
         redirect = strtok (NULL, " "))
    {
      if (NULL == (hostname = strstr (redirect, ":")))
      {
        GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
                    "Warning: option %s is not formatted correctly!\n",
                    redirect);
        continue;
      }
      hostname[0] = '\0';
      local_port = atoi (redirect);
      if (!((local_port > 0) && (local_port < 65536)))
        GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
                    "Warning: %s is not a correct port.", redirect);

      ret |= (0xFFFF & htons (local_port));
      ret <<= 16;
      count++;

      if (count > 4)
      {
        ret = 0;
        goto out;
      }
    }
    GNUNET_free (cpy);
    cpy = NULL;
  }

  if (NULL != tcp_redirects)
  {
    cpy = GNUNET_strdup (tcp_redirects);
    for (redirect = strtok (cpy, " "); redirect != NULL;
         redirect = strtok (NULL, " "))
    {
      if (NULL == (hostname = strstr (redirect, ":")))
      {
        GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
                    "Warning: option %s is not formatted correctly!\n",
                    redirect);
        continue;
      }
      hostname[0] = '\0';
      local_port = atoi (redirect);
      if (!((local_port > 0) && (local_port < 65536)))
        GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
                    "Warning: %s is not a correct port.", redirect);

      ret |= (0xFFFF & htons (local_port));
      ret <<= 16;
      count++;

      if (count > 4)
      {
        ret = 0;
        goto out;
      }
    }
    GNUNET_free (cpy);
    cpy = NULL;
  }

out:
  GNUNET_free_non_null (cpy);
  return ret;
}

static void
publish_name (const char *name, uint64_t ports, uint32_t service_type,
              struct GNUNET_CRYPTO_RsaPrivateKey *my_private_key)
{
  size_t size = sizeof (struct GNUNET_DNS_Record);
  struct GNUNET_DNS_Record data;

  memset (&data, 0, size);

  data.purpose.size = htonl (size - sizeof (struct GNUNET_CRYPTO_RsaSignature));
  data.purpose.purpose = GNUNET_SIGNATURE_PURPOSE_DNS_RECORD;

  GNUNET_CRYPTO_hash (name, strlen (name) + 1, &data.service_descriptor);
  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Store with key1 %x\n",
              *((unsigned long long *) &data.service_descriptor));

  data.service_type = service_type;
  data.ports = ports;

  GNUNET_CRYPTO_rsa_key_get_public (my_private_key, &data.peer);

  data.expiration_time =
      GNUNET_TIME_absolute_hton (GNUNET_TIME_relative_to_absolute
                                 (GNUNET_TIME_relative_multiply
                                  (GNUNET_TIME_UNIT_HOURS, 2)));

  /* Sign the block */
  if (GNUNET_OK !=
      GNUNET_CRYPTO_rsa_sign (my_private_key, &data.purpose, &data.signature))
  {
    GNUNET_log (GNUNET_ERROR_TYPE_ERROR, "could not sign DNS_Record\n");
    return;
  }

  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Putting with key %08x, size = %d\n",
              *((unsigned int *) &data.service_descriptor), size);

  GNUNET_DHT_put (dht, &data.service_descriptor,
                  5 /* DEFAULT_PUT_REPLICATION */ ,
                  GNUNET_DHT_RO_NONE, GNUNET_BLOCK_TYPE_DNS, size,
                  (char *) &data,
                  GNUNET_TIME_relative_to_absolute (GNUNET_TIME_UNIT_HOURS),
                  GNUNET_TIME_UNIT_MINUTES, NULL, NULL);
}


/**
 * @brief Publishes the record defined by the section section
 *
 * @param cls closure
 * @param section the current section
 */
static void
publish_iterate (void *cls GNUNET_UNUSED, const char *section)
{
  char *udp_redirects;
  char *tcp_redirects;
  char *alternative_names;
  char *alternative_name;
  char *keyfile;

  if ((strlen (section) < 8) ||
      (0 != strcmp (".gnunet.", section + (strlen (section) - 8))))
    return;
  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Parsing dns-name %s\n", section);
  if (GNUNET_OK !=
      GNUNET_CONFIGURATION_get_value_string (cfg, section, "UDP_REDIRECTS",
                                             &udp_redirects))
    udp_redirects = NULL;
  if (GNUNET_OK !=
      GNUNET_CONFIGURATION_get_value_string (cfg, section, "TCP_REDIRECTS",
                                             &tcp_redirects))
    tcp_redirects = NULL;

  if (GNUNET_OK !=
      GNUNET_CONFIGURATION_get_value_filename (cfg, "GNUNETD", "HOSTKEY",
                                               &keyfile))
  {
    GNUNET_log (GNUNET_ERROR_TYPE_ERROR, "could not read keyfile-value\n");
    if (keyfile != NULL)
      GNUNET_free (keyfile);
    return;
  }

  struct GNUNET_CRYPTO_RsaPrivateKey *my_private_key =
      GNUNET_CRYPTO_rsa_key_create_from_file (keyfile);
  GNUNET_free (keyfile);
  GNUNET_assert (my_private_key != NULL);

  uint64_t ports = get_port_from_redirects (udp_redirects, tcp_redirects);
  uint32_t service_type = 0;

  if (NULL != udp_redirects)
    service_type = GNUNET_DNS_SERVICE_TYPE_UDP;

  if (NULL != tcp_redirects)
    service_type |= GNUNET_DNS_SERVICE_TYPE_TCP;

  service_type = htonl (service_type);


  publish_name (section, ports, service_type, my_private_key);
  if (GNUNET_OK ==
      GNUNET_CONFIGURATION_get_value_string (cfg, section, "ALTERNATIVE_NAMES",
                                             &alternative_names))
  {
    for (alternative_name = strtok (alternative_names, " ");
         alternative_name != NULL; alternative_name = strtok (NULL, " "))
    {
      char *altname =
          alloca (strlen (alternative_name) + strlen (section) + 1 + 1);
      strcpy (altname, alternative_name);
      strcpy (altname + strlen (alternative_name) + 1, section);
      altname[strlen (alternative_name)] = '.';

      publish_name (altname, ports, service_type, my_private_key);
    }
    GNUNET_free (alternative_names);
  }
  GNUNET_CRYPTO_rsa_key_free (my_private_key);
  GNUNET_free_non_null (udp_redirects);
  GNUNET_free_non_null (tcp_redirects);
}

/**
 * Publish a DNS-record in the DHT.
 */
static void
publish_names (void *cls GNUNET_UNUSED,
               const struct GNUNET_SCHEDULER_TaskContext *tc)
{
  if (0 != (tc->reason & GNUNET_SCHEDULER_REASON_SHUTDOWN))
    return;

  GNUNET_CONFIGURATION_iterate_sections (cfg, &publish_iterate, NULL);

  GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_UNIT_HOURS, &publish_names, NULL);
}

/**
 * @param cls closure
 * @param server the initialized server
 * @param cfg_ configuration to use
 */
static void
run (void *cls, struct GNUNET_SERVER_Handle *server,
     const struct GNUNET_CONFIGURATION_Handle *cfg_)
{
  static const struct GNUNET_SERVER_MessageHandler handlers[] = {
    /* callback, cls, type, size */
    {&receive_query, NULL, GNUNET_MESSAGE_TYPE_VPN_DNS_LOCAL_QUERY_DNS, 0},
    {&rehijack, NULL, GNUNET_MESSAGE_TYPE_REHIJACK,
     sizeof (struct GNUNET_MessageHeader)},
    {NULL, NULL, 0, 0}
  };

  static const struct GNUNET_MESH_MessageHandler mesh_handlers[] = {
    {receive_mesh_query, GNUNET_MESSAGE_TYPE_VPN_REMOTE_QUERY_DNS, 0},
    {receive_mesh_answer, GNUNET_MESSAGE_TYPE_VPN_REMOTE_ANSWER_DNS, 0},
    {NULL, 0, 0}
  };

  static GNUNET_MESH_ApplicationType apptypes[] = {
    GNUNET_APPLICATION_TYPE_END,
    GNUNET_APPLICATION_TYPE_END
  };

  if (GNUNET_YES != open_port6 ())
  {
    GNUNET_SCHEDULER_shutdown ();
    return;
  }

  if (GNUNET_YES != open_port ())
  {
    GNUNET_SCHEDULER_shutdown ();
    return;
  }

  if (GNUNET_YES ==
      GNUNET_CONFIGURATION_get_value_yesno (cfg_, "dns", "PROVIDE_EXIT"))
    apptypes[0] = GNUNET_APPLICATION_TYPE_INTERNET_RESOLVER;
  mesh_handle =
      GNUNET_MESH_connect (cfg_, 42, NULL, new_tunnel, clean_tunnel,
                           mesh_handlers, apptypes);

  cfg = cfg_;
  dht = GNUNET_DHT_connect (cfg, 1024);
  GNUNET_SCHEDULER_add_now (publish_names, NULL);
  GNUNET_SERVER_add_handlers (server, handlers);
  GNUNET_SERVER_disconnect_notify (server, &client_disconnect, NULL);
  GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_UNIT_FOREVER_REL, &cleanup_task,
                                cls);
}

/**
 * The main function for the dns service.
 *
 * @param argc number of arguments from the command line
 * @param argv command line arguments
 * @return 0 ok, 1 on error
 */
int
main (int argc, char *const *argv)
{
  return (GNUNET_OK ==
          GNUNET_SERVICE_run (argc, argv, "dns", GNUNET_SERVICE_OPTION_NONE,
                              &run, NULL)) ? 0 : 1;
}