DNS server that translates DNS requests to GNS. More...

#include "platform.h"
#include <gnunet_util_lib.h>
#include <gnunet_gns_service.h>
#include "gnunet_vpn_service.h"

Include dependency graph for gnunet-dns2gns.c:

Go to the source code of this file.

Data Structures
struct	VpnContext
	Closure for vpn_allocation_cb. More...

struct	Request
	Request we should make. More...

Macros
#define	TIMEOUT GNUNET_TIME_UNIT_MINUTES
	Timeout for DNS requests.

#define	VPN_TIMEOUT GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_MINUTES, 30)
	Default timeout for VPN redirections.

Functions
static void	do_shutdown (void *cls)
	Task run on shutdown.

static void	shuffle_answers (struct Request *request)
	Shuffle answers Fisher-Yates (aka Knuth) Shuffle.

static void	send_response (struct Request *request)
	Send the response for the given request and clean up.

static void	do_timeout (void *cls)
	Task run on timeout.

static void	dns_result_processor (void cls, const struct GNUNET_TUN_DnsHeader dns, size_t r)
	Iterator called on obtained result for a DNS lookup.

static void	vpn_allocation_cb (void cls, int af, const void vaddress)
	Callback invoked from the VPN service once a redirection is available.

static void	result_processor (void cls, int was_gns, uint32_t rd_count, const struct GNUNET_GNSRECORD_Data rd)
	Iterator called on obtained result for a GNS lookup.

static void	handle_request (struct GNUNET_NETWORK_Handle lsock, const void addr, size_t addr_len, const char *udp_msg, size_t udp_msg_size)
	Handle DNS request.

static void	read_dns4 (void *cls)
	Task to read IPv4 DNS packets.

static void	read_dns6 (void *cls)
	Task to read IPv6 DNS packets.

static void	run (void cls, char const args, const char cfgfile, const struct GNUNET_CONFIGURATION_Handle *c)
	Main function that will be run.

int	main (int argc, char const argv)
	The main function for the dns2gns daemon.

Variables
static in_addr_t	address
	The address to bind to.

static struct in6_addr	address6
	The IPv6 address to bind to.

struct GNUNET_GNS_Handle *	gns
	Handle to GNS resolver.

static struct GNUNET_VPN_Handle *	vpn_handle
	Our handle to the vpn service.

struct GNUNET_DNSSTUB_Context *	dns_stub
	Stub resolver.

static struct GNUNET_NETWORK_Handle *	listen_socket4
	Listen socket for IPv4.

static struct GNUNET_NETWORK_Handle *	listen_socket6
	Listen socket for IPv6.

static struct GNUNET_SCHEDULER_Task *	t4
	Task for IPv4 socket.

static struct GNUNET_SCHEDULER_Task *	t6
	Task for IPv6 socket.

static char *	dns_ip
	IP of DNS server.

static unsigned long long	listen_port = 53
	UDP Port we listen on for inbound DNS requests.

static const struct GNUNET_CONFIGURATION_Handle *	cfg
	Configuration to use.

Detailed Description

DNS server that translates DNS requests to GNS.

Author: Christian Grothoff

Definition in file gnunet-dns2gns.c.

Macro Definition Documentation

◆ TIMEOUT

#define TIMEOUT GNUNET_TIME_UNIT_MINUTES

Timeout for DNS requests.

Definition at line 33 of file gnunet-dns2gns.c.

◆ VPN_TIMEOUT

#define VPN_TIMEOUT GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_MINUTES, 30)

Default timeout for VPN redirections.

Definition at line 38 of file gnunet-dns2gns.c.

Function Documentation

◆ do_shutdown()

static void do_shutdown ( void * cls )

static

Task run on shutdown.

Cleans up everything.

Parameters

cls unused

Definition at line 207 of file gnunet-dns2gns.c.

{
  (void) cls;
  if (NULL != t4)
  {
    GNUNET_SCHEDULER_cancel (t4);
    t4 = NULL;
  }
  if (NULL != t6)
  {
    GNUNET_SCHEDULER_cancel (t6);
    t6 = NULL;
  }
  if (NULL != listen_socket4)
  {
    GNUNET_NETWORK_socket_close (listen_socket4);
    listen_socket4 = NULL;
  }
  if (NULL != listen_socket6)
  {
    GNUNET_NETWORK_socket_close (listen_socket6);
    listen_socket6 = NULL;
  }
  if (NULL != gns)
  {
    GNUNET_GNS_disconnect (gns);
    gns = NULL;
  }
  if (NULL != vpn_handle)
  {
    GNUNET_VPN_disconnect (vpn_handle);
    vpn_handle = NULL;
  }
  if (NULL != dns_stub)
  {
    GNUNET_DNSSTUB_stop (dns_stub);
    dns_stub = NULL;
  }
}

References dns_stub, gns, GNUNET_DNSSTUB_stop(), GNUNET_GNS_disconnect(), GNUNET_NETWORK_socket_close(), GNUNET_SCHEDULER_cancel(), GNUNET_VPN_disconnect(), listen_socket4, listen_socket6, t4, t6, and vpn_handle.

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◆ shuffle_answers()

static void shuffle_answers ( struct Request * request )

static

Shuffle answers Fisher-Yates (aka Knuth) Shuffle.

Parameters

request context for the request (with answers)

Definition at line 255 of file gnunet-dns2gns.c.

{
  unsigned int idx = request->packet->num_answers;
  unsigned int r_idx;
  struct GNUNET_DNSPARSER_Record tmp_answer;
 
  while (0 != idx)
  {
    r_idx = GNUNET_CRYPTO_random_u32 (request->packet->num_answers);
    idx--;
    tmp_answer = request->packet->answers[idx];
    memcpy (&request->packet->answers[idx], &request->packet->answers[r_idx],
            sizeof (struct GNUNET_DNSPARSER_Record));
    memcpy (&request->packet->answers[r_idx], &tmp_answer,
            sizeof (struct GNUNET_DNSPARSER_Record));
  }
}

References GNUNET_CRYPTO_random_u32(), and request.

Referenced by send_response().

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◆ send_response()

static void send_response ( struct Request * request )

static

Send the response for the given request and clean up.

Parameters

request context for the request.

Definition at line 280 of file gnunet-dns2gns.c.

{
  char *buf;
  size_t size;
  ssize_t sret;
 
  shuffle_answers (request);
  if (GNUNET_SYSERR ==
      GNUNET_DNSPARSER_pack (request->packet,
                             UINT16_MAX /* is this not too much? */,
                             &buf,
                             &size))
  {
    GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
                _ ("Failed to pack DNS response into UDP packet!\n"));
  }
  else
  {
    sret = GNUNET_NETWORK_socket_sendto (request->lsock,
                                         buf,
                                         size,
                                         request->addr,
                                         request->addr_len);
    if ((sret < 0) ||
        (size != (size_t) sret))
      GNUNET_log_strerror (GNUNET_ERROR_TYPE_WARNING,
                           "sendto");
    GNUNET_free (buf);
  }
  GNUNET_SCHEDULER_cancel (request->timeout_task);
  GNUNET_DNSPARSER_free_packet (request->packet);
  GNUNET_free (request->udp_msg);
  GNUNET_free (request);
}

References _, GNUNET_VPN_RedirectionRequest::addr, GNUNET_DNSPARSER_free_packet(), GNUNET_DNSPARSER_pack(), GNUNET_ERROR_TYPE_WARNING, GNUNET_free, GNUNET_log, GNUNET_log_strerror, GNUNET_NETWORK_socket_sendto(), GNUNET_SCHEDULER_cancel(), GNUNET_SYSERR, request, shuffle_answers(), and size.

Referenced by dns_result_processor(), iterate_srv_handle_sync_finished(), result_processor(), and vpn_allocation_cb().

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◆ do_timeout()

static void do_timeout ( void * cls )

static

Task run on timeout.

Cleans up request.

Parameters

cls	`struct Request *` of the request to clean up

Definition at line 322 of file gnunet-dns2gns.c.

{
  struct Request *request = cls;
  struct VpnContext *vpn_ctx;
 
  if (NULL != request->packet)
    GNUNET_DNSPARSER_free_packet (request->packet);
  if (NULL != request->lookup)
    GNUNET_GNS_lookup_with_tld_cancel (request->lookup);
  if (NULL != request->dns_lookup)
    GNUNET_DNSSTUB_resolve_cancel (request->dns_lookup);
  GNUNET_free (request->udp_msg);
  if (NULL != (vpn_ctx = request->vpn_ctx))
  {
    GNUNET_VPN_cancel_request (vpn_ctx->vpn_request);
    GNUNET_free (vpn_ctx->rd_data);
    GNUNET_free (vpn_ctx);
  }
  GNUNET_free (request);
}

References GNUNET_DNSPARSER_free_packet(), GNUNET_DNSSTUB_resolve_cancel(), GNUNET_free, GNUNET_GNS_lookup_with_tld_cancel(), GNUNET_VPN_cancel_request(), VpnContext::rd_data, request, and VpnContext::vpn_request.

Referenced by dns_result_processor(), and handle_request().

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◆ dns_result_processor()

static void dns_result_processor	(	void *	cls,
		const struct GNUNET_TUN_DnsHeader *	dns,
		size_t	r
	)

static

Iterator called on obtained result for a DNS lookup.

Parameters

cls	closure
dns	the DNS udp payload
r	size of the DNS payload

Definition at line 352 of file gnunet-dns2gns.c.

{
  struct Request *request = cls;
 
  if (NULL == dns)
  {
    /* DNSSTUB gave up, so we trigger timeout early */
    GNUNET_SCHEDULER_cancel (request->timeout_task);
    do_timeout (request);
    return;
  }
  if (request->original_request_id != dns->id)
  {
    /* for a another query, ignore */
    return;
  }
  request->packet = GNUNET_DNSPARSER_parse ((char *) dns,
                                            r);
  if (NULL == request->packet)
  {
    GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
                _ ("Failed to parse DNS response!\n"));
    GNUNET_SCHEDULER_cancel (request->timeout_task);
    do_timeout (request);
    return;
  }
  GNUNET_DNSSTUB_resolve_cancel (request->dns_lookup);
  send_response (request);
}

References _, do_timeout(), GNUNET_DNSPARSER_parse(), GNUNET_DNSSTUB_resolve_cancel(), GNUNET_ERROR_TYPE_WARNING, GNUNET_log, GNUNET_SCHEDULER_cancel(), GNUNET_TUN_DnsHeader::id, request, and send_response().

Referenced by result_processor().

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◆ vpn_allocation_cb()

static void vpn_allocation_cb	(	void *	cls,
		int	af,
		const void *	vaddress
	)

static

Callback invoked from the VPN service once a redirection is available.

Provides the IP address that can now be used to reach the requested destination. Replaces the "VPN" record with the respective A/AAAA record and continues processing.

Parameters

cls	closure
af	address family, AF_INET or AF_INET6; AF_UNSPEC on error; will match 'result_af' from the request
address	IP address (struct in_addr or struct in_addr6, depending on 'af') that the VPN allocated for the redirection; traffic to this IP will now be redirected to the specified target peer; NULL on error

Definition at line 400 of file gnunet-dns2gns.c.

{
  struct VpnContext *vpn_ctx = cls;
  struct Request *request = vpn_ctx->request;
  struct GNUNET_GNSRECORD_Data rd[vpn_ctx->rd_count];
  unsigned int i;
 
  vpn_ctx->vpn_request = NULL;
  request->vpn_ctx = NULL;
  GNUNET_assert (GNUNET_OK ==
                 GNUNET_GNSRECORD_records_deserialize (
                   (size_t) vpn_ctx->rd_data_size,
                   vpn_ctx->rd_data,
                   vpn_ctx->rd_count,
                   rd));
  for (i = 0; i < vpn_ctx->rd_count; i++)
  {
    if (GNUNET_GNSRECORD_TYPE_VPN == rd[i].record_type)
    {
      switch (af)
      {
      case AF_INET:
        rd[i].record_type = GNUNET_DNSPARSER_TYPE_A;
        rd[i].data_size = sizeof(struct in_addr);
        rd[i].expiration_time = GNUNET_TIME_relative_to_absolute (
          VPN_TIMEOUT).abs_value_us;
        rd[i].flags = 0;
        rd[i].data = vaddress;
        break;
 
      case AF_INET6:
        rd[i].record_type = GNUNET_DNSPARSER_TYPE_AAAA;
        rd[i].expiration_time = GNUNET_TIME_relative_to_absolute (
          VPN_TIMEOUT).abs_value_us;
        rd[i].flags = 0;
        rd[i].data = vaddress;
        rd[i].data_size = sizeof(struct in6_addr);
        break;
 
      default:
        GNUNET_assert (0);
      }
      break;
    }
  }
  GNUNET_assert (i < vpn_ctx->rd_count);
  if (0 == vpn_ctx->rd_count)
    GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
                _ ("VPN returned empty result for `%s'\n"),
                request->packet->queries[0].name);
  send_response (request);
  GNUNET_free (vpn_ctx->rd_data);
  GNUNET_free (vpn_ctx);
}

References _, GNUNET_TIME_Absolute::abs_value_us, GNUNET_GNSRECORD_Data::data, GNUNET_GNSRECORD_Data::data_size, GNUNET_GNSRECORD_Data::expiration_time, GNUNET_GNSRECORD_Data::flags, GNUNET_assert, GNUNET_DNSPARSER_TYPE_A, GNUNET_DNSPARSER_TYPE_AAAA, GNUNET_ERROR_TYPE_WARNING, GNUNET_free, GNUNET_GNSRECORD_records_deserialize(), GNUNET_GNSRECORD_TYPE_VPN, GNUNET_log, GNUNET_OK, GNUNET_TIME_relative_to_absolute(), rd, rd_count, VpnContext::rd_count, VpnContext::rd_data, VpnContext::rd_data_size, GNUNET_GNSRECORD_Data::record_type, request, VpnContext::request, send_response(), Request::vpn_ctx, VpnContext::vpn_request, and VPN_TIMEOUT.

Referenced by result_processor().

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◆ result_processor()

static void result_processor	(	void *	cls,
		int	was_gns,
		uint32_t	rd_count,
		const struct GNUNET_GNSRECORD_Data *	rd
	)

static

Iterator called on obtained result for a GNS lookup.

Parameters

cls	closure
was_gns	GNUNET_NO if the TLD is not configured for GNS
rd_count	number of records in rd
rd	the records in reply

Definition at line 467 of file gnunet-dns2gns.c.

{
  struct Request *request = cls;
  struct GNUNET_DNSPARSER_Packet *packet;
  struct GNUNET_DNSPARSER_Record rec;
  struct VpnContext *vpn_ctx;
  const struct GNUNET_TUN_GnsVpnRecord *vpn;
  const char *vname;
  struct GNUNET_HashCode vhash;
  int af;
 
  request->lookup = NULL;
  if (GNUNET_NO == was_gns)
  {
    /* TLD not configured for GNS, fall back to DNS */
    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
                "Using DNS resolver IP `%s' to resolve `%s'\n",
                dns_ip,
                request->packet->queries[0].name);
    request->original_request_id = request->packet->id;
    GNUNET_DNSPARSER_free_packet (request->packet);
    request->packet = NULL;
    request->dns_lookup = GNUNET_DNSSTUB_resolve (dns_stub,
                                                  request->udp_msg,
                                                  request->udp_msg_size,
                                                  &dns_result_processor,
                                                  request);
    return;
  }
  packet = request->packet;
  packet->flags.query_or_response = 1;
  packet->flags.return_code = GNUNET_TUN_DNS_RETURN_CODE_NO_ERROR;
  packet->flags.checking_disabled = 0;
  packet->flags.authenticated_data = 1;
  packet->flags.zero = 0;
  packet->flags.recursion_available = 1;
  packet->flags.message_truncated = 0;
  packet->flags.authoritative_answer = 0;
  // packet->flags.opcode = GNUNET_TUN_DNS_OPCODE_STATUS; // ???
  for (uint32_t i = 0; i < rd_count; i++)
  {
    rec.expiration_time.abs_value_us = rd[i].expiration_time;
    switch (rd[i].record_type)
    {
    case GNUNET_DNSPARSER_TYPE_A:
      GNUNET_assert (sizeof(struct in_addr) == rd[i].data_size);
      rec.name = GNUNET_strdup (packet->queries[0].name);
      rec.dns_traffic_class = GNUNET_TUN_DNS_CLASS_INTERNET;
      rec.type = GNUNET_DNSPARSER_TYPE_A;
      rec.data.raw.data = GNUNET_new (struct in_addr);
      GNUNET_memcpy (rec.data.raw.data,
                     rd[i].data,
                     rd[i].data_size);
      rec.data.raw.data_len = sizeof(struct in_addr);
      GNUNET_array_append (packet->answers,
                           packet->num_answers,
                           rec);
      break;
 
    case GNUNET_DNSPARSER_TYPE_AAAA:
      GNUNET_assert (sizeof(struct in6_addr) == rd[i].data_size);
      rec.name = GNUNET_strdup (packet->queries[0].name);
      rec.data.raw.data = GNUNET_new (struct in6_addr);
      rec.dns_traffic_class = GNUNET_TUN_DNS_CLASS_INTERNET;
      rec.type = GNUNET_DNSPARSER_TYPE_AAAA;
      GNUNET_memcpy (rec.data.raw.data,
                     rd[i].data,
                     rd[i].data_size);
      rec.data.raw.data_len = sizeof(struct in6_addr);
      GNUNET_array_append (packet->answers,
                           packet->num_answers,
                           rec);
      break;
 
    case GNUNET_DNSPARSER_TYPE_CNAME:
      rec.name = GNUNET_strdup (packet->queries[0].name);
      rec.data.hostname = GNUNET_strdup (rd[i].data);
      rec.dns_traffic_class = GNUNET_TUN_DNS_CLASS_INTERNET;
      rec.type = GNUNET_DNSPARSER_TYPE_CNAME;
      GNUNET_memcpy (rec.data.hostname,
                     rd[i].data,
                     rd[i].data_size);
      GNUNET_array_append (packet->answers,
                           packet->num_answers,
                           rec);
      break;
    case GNUNET_GNSRECORD_TYPE_VPN:
      if ((GNUNET_DNSPARSER_TYPE_A != request->packet->queries[0].type) &&
          (GNUNET_DNSPARSER_TYPE_AAAA != request->packet->queries[0].type))
        break;
      af = (GNUNET_DNSPARSER_TYPE_A == request->packet->queries[0].type) ?
           AF_INET :
           AF_INET6;
      if (sizeof(struct GNUNET_TUN_GnsVpnRecord) >
          rd[i].data_size)
      {
        GNUNET_break_op (0);
        break;
      }
      vpn = (const struct GNUNET_TUN_GnsVpnRecord *) rd[i].data;
      vname = (const char *) &vpn[1];
      if ('\0' != vname[rd[i].data_size - 1 - sizeof(struct
                                                     GNUNET_TUN_GnsVpnRecord)
          ])
      {
        GNUNET_break_op (0);
        break;
      }
      GNUNET_TUN_service_name_to_hash (vname,
                                       &vhash);
      GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
                  "Attempting VPN allocation for %s-%s (AF: %d, proto %d)\n",
                  GNUNET_i2s (&vpn->peer),
                  vname,
                  (int) af,
                  (int) ntohs (vpn->proto));
      vpn_ctx = GNUNET_new (struct VpnContext);
      request->vpn_ctx = vpn_ctx;
      vpn_ctx->request = request;
      vpn_ctx->rd_data_size = GNUNET_GNSRECORD_records_get_size (rd_count,
                                                                 rd);
      if (vpn_ctx->rd_data_size < 0)
      {
        GNUNET_break_op (0);
        GNUNET_free (vpn_ctx);
        break;
      }
      vpn_ctx->rd_data = GNUNET_malloc ((size_t) vpn_ctx->rd_data_size);
      vpn_ctx->rd_count = rd_count;
      GNUNET_assert (vpn_ctx->rd_data_size ==
                     GNUNET_GNSRECORD_records_serialize (rd_count,
                                                         rd,
                                                         (size_t) vpn_ctx
                                                         ->rd_data_size,
                                                         vpn_ctx->rd_data));
      vpn_ctx->vpn_request = GNUNET_VPN_redirect_to_peer (vpn_handle,
                                                          af,
                                                          ntohs (
                                                            vpn->proto),
                                                          &vpn->peer,
                                                          &vhash,
                                                          GNUNET_TIME_relative_to_absolute
                                                          (
                                                            VPN_TIMEOUT),
                                                          &
                                                          vpn_allocation_cb,
                                                          vpn_ctx);
      return;
 
 
    default:
      /* skip */
      break;
    }
  }
  send_response (request);
}

References GNUNET_TIME_Absolute::abs_value_us, GNUNET_DNSPARSER_Packet::answers, GNUNET_TUN_DnsFlags::authenticated_data, GNUNET_TUN_DnsFlags::authoritative_answer, GNUNET_TUN_DnsFlags::checking_disabled, data, GNUNET_DNSPARSER_RawRecord::data, GNUNET_DNSPARSER_Record::data, GNUNET_GNSRECORD_Data::data, GNUNET_DNSPARSER_RawRecord::data_len, data_size, GNUNET_GNSRECORD_Data::data_size, dns_ip, dns_result_processor(), dns_stub, GNUNET_DNSPARSER_Record::dns_traffic_class, GNUNET_DNSPARSER_Record::expiration_time, GNUNET_GNSRECORD_Data::expiration_time, GNUNET_DNSPARSER_Packet::flags, GNUNET_array_append, GNUNET_assert, GNUNET_break_op, GNUNET_DNSPARSER_free_packet(), GNUNET_DNSPARSER_TYPE_A, GNUNET_DNSPARSER_TYPE_AAAA, GNUNET_DNSPARSER_TYPE_CNAME, GNUNET_DNSSTUB_resolve(), GNUNET_ERROR_TYPE_DEBUG, GNUNET_free, GNUNET_GNSRECORD_records_get_size(), GNUNET_GNSRECORD_records_serialize(), GNUNET_GNSRECORD_TYPE_VPN, GNUNET_i2s(), GNUNET_log, GNUNET_malloc, GNUNET_memcpy, GNUNET_new, GNUNET_NO, GNUNET_strdup, GNUNET_TIME_relative_to_absolute(), GNUNET_TUN_DNS_CLASS_INTERNET, GNUNET_TUN_DNS_RETURN_CODE_NO_ERROR, GNUNET_TUN_service_name_to_hash(), GNUNET_VPN_redirect_to_peer(), GNUNET_DNSPARSER_Record::hostname, GNUNET_TUN_DnsFlags::message_truncated, GNUNET_DNSPARSER_Query::name, GNUNET_DNSPARSER_Record::name, GNUNET_DNSPARSER_Packet::num_answers, GNUNET_TUN_GnsVpnRecord::peer, GNUNET_TUN_GnsVpnRecord::proto, GNUNET_DNSPARSER_Packet::queries, GNUNET_TUN_DnsFlags::query_or_response, GNUNET_DNSPARSER_Record::raw, rd, rd_count, VpnContext::rd_count, VpnContext::rd_data, VpnContext::rd_data_size, GNUNET_TUN_DnsFlags::recursion_available, request, VpnContext::request, GNUNET_TUN_DnsFlags::return_code, send_response(), GNUNET_DNSPARSER_Record::type, vpn_allocation_cb(), vpn_handle, VpnContext::vpn_request, VPN_TIMEOUT, and GNUNET_TUN_DnsFlags::zero.

Referenced by handle_request().

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◆ handle_request()

static void handle_request	(	struct GNUNET_NETWORK_Handle *	lsock,
		const void *	addr,
		size_t	addr_len,
		const char *	udp_msg,
		size_t	udp_msg_size
	)

static

Handle DNS request.

Parameters

lsock	socket to use for sending the reply
addr	address to use for sending the reply
addr_len	number of bytes in addr
udp_msg	DNS request payload
udp_msg_size	number of bytes in udp_msg

Definition at line 639 of file gnunet-dns2gns.c.

{
  struct Request *request;
  struct GNUNET_DNSPARSER_Packet *packet;
 
  packet = GNUNET_DNSPARSER_parse (udp_msg,
                                   udp_msg_size);
  if (NULL == packet)
  {
    GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
                _ ("Cannot parse DNS request from %s\n"),
                GNUNET_a2s (addr, addr_len));
    return;
  }
  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
              "Received request for `%s' with flags %u, #answers %d, #auth %d, #additional %d\n",
              packet->queries[0].name,
              (unsigned int) packet->flags.query_or_response,
              (int) packet->num_answers,
              (int) packet->num_authority_records,
              (int) packet->num_additional_records);
  if ((0 != packet->flags.query_or_response) ||
      (0 != packet->num_answers) ||
      (0 != packet->num_authority_records))
  {
    GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
                _ ("Received malformed DNS request from %s\n"),
                GNUNET_a2s (addr, addr_len));
    GNUNET_DNSPARSER_free_packet (packet);
    return;
  }
  if ((1 != packet->num_queries))
  {
    GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
                _ ("Received unsupported DNS request from %s\n"),
                GNUNET_a2s (addr,
                            addr_len));
    GNUNET_DNSPARSER_free_packet (packet);
    return;
  }
  request = GNUNET_malloc (sizeof(struct Request) + addr_len);
  request->lsock = lsock;
  request->packet = packet;
  request->addr = &request[1];
  request->addr_len = addr_len;
  GNUNET_memcpy (&request[1],
                 addr,
                 addr_len);
  request->udp_msg_size = udp_msg_size;
  request->udp_msg = GNUNET_memdup (udp_msg,
                                    udp_msg_size);
  request->timeout_task = GNUNET_SCHEDULER_add_delayed (TIMEOUT,
                                                        &do_timeout,
                                                        request);
  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
              "Calling GNS on `%s'\n",
              packet->queries[0].name);
  request->lookup = GNUNET_GNS_lookup_with_tld (gns,
                                                packet->queries[0].name,
                                                packet->queries[0].type,
                                                GNUNET_GNS_LO_DEFAULT,
                                                &result_processor,
                                                request);
}

References _, GNUNET_VPN_RedirectionRequest::addr, do_timeout(), GNUNET_DNSPARSER_Packet::flags, gns, GNUNET_a2s(), GNUNET_DNSPARSER_free_packet(), GNUNET_DNSPARSER_parse(), GNUNET_ERROR_TYPE_DEBUG, GNUNET_ERROR_TYPE_WARNING, GNUNET_GNS_LO_DEFAULT, GNUNET_GNS_lookup_with_tld(), GNUNET_log, GNUNET_malloc, GNUNET_memcpy, GNUNET_memdup, GNUNET_SCHEDULER_add_delayed(), GNUNET_DNSPARSER_Query::name, GNUNET_DNSPARSER_Packet::num_additional_records, GNUNET_DNSPARSER_Packet::num_answers, GNUNET_DNSPARSER_Packet::num_authority_records, GNUNET_DNSPARSER_Packet::num_queries, GNUNET_DNSPARSER_Packet::queries, GNUNET_TUN_DnsFlags::query_or_response, request, result_processor(), TIMEOUT, and GNUNET_DNSPARSER_Query::type.

Referenced by read_dns4(), and read_dns6().

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◆ read_dns4()

static void read_dns4 ( void * cls )

static

Task to read IPv4 DNS packets.

Parameters

cls	the 'listen_socket4'

Definition at line 715 of file gnunet-dns2gns.c.

{
  struct sockaddr_in v4;
  socklen_t addrlen;
  ssize_t size;
  const struct GNUNET_SCHEDULER_TaskContext *tc;
 
  GNUNET_assert (listen_socket4 == cls);
  t4 = GNUNET_SCHEDULER_add_read_net (GNUNET_TIME_UNIT_FOREVER_REL,
                                      listen_socket4,
                                      &read_dns4,
                                      listen_socket4);
  tc = GNUNET_SCHEDULER_get_task_context ();
  if (0 == (GNUNET_SCHEDULER_REASON_READ_READY & tc->reason))
    return; /* shutdown? */
  size = GNUNET_NETWORK_socket_recvfrom_amount (listen_socket4);
  if (0 > size)
  {
    GNUNET_break (0);
    return;   /* read error!? */
  }
  {
    char buf[size + 1];
    ssize_t sret;
 
    addrlen = sizeof(v4);
    sret = GNUNET_NETWORK_socket_recvfrom (listen_socket4,
                                           buf,
                                           size + 1,
                                           (struct sockaddr *) &v4,
                                           &addrlen);
    if (0 > sret)
    {
      GNUNET_log_strerror (GNUNET_ERROR_TYPE_WARNING,
                           "recvfrom");
      return;
    }
    GNUNET_break (size != sret);
    handle_request (listen_socket4,
                    &v4,
                    addrlen,
                    buf,
                    size);
  }
}

References GNUNET_assert, GNUNET_break, GNUNET_ERROR_TYPE_WARNING, GNUNET_log_strerror, GNUNET_NETWORK_socket_recvfrom(), GNUNET_NETWORK_socket_recvfrom_amount(), GNUNET_SCHEDULER_add_read_net(), GNUNET_SCHEDULER_get_task_context(), GNUNET_SCHEDULER_REASON_READ_READY, GNUNET_TIME_UNIT_FOREVER_REL, handle_request(), listen_socket4, read_dns4(), GNUNET_SCHEDULER_TaskContext::reason, size, t4, and tc.

Referenced by read_dns4(), and run().

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◆ read_dns6()

static void read_dns6 ( void * cls )

static

Task to read IPv6 DNS packets.

Parameters

cls	the 'listen_socket6'

Definition at line 768 of file gnunet-dns2gns.c.

{
  struct sockaddr_in6 v6;
  socklen_t addrlen;
  ssize_t size;
  const struct GNUNET_SCHEDULER_TaskContext *tc;
 
  GNUNET_assert (listen_socket6 == cls);
  t6 = GNUNET_SCHEDULER_add_read_net (GNUNET_TIME_UNIT_FOREVER_REL,
                                      listen_socket6,
                                      &read_dns6,
                                      listen_socket6);
  tc = GNUNET_SCHEDULER_get_task_context ();
  if (0 == (GNUNET_SCHEDULER_REASON_READ_READY & tc->reason))
    return; /* shutdown? */
  size = GNUNET_NETWORK_socket_recvfrom_amount (listen_socket6);
  if (0 > size)
  {
    GNUNET_break (0);
    return;   /* read error!? */
  }
  {
    char buf[size];
    ssize_t sret;
 
    addrlen = sizeof(v6);
    sret = GNUNET_NETWORK_socket_recvfrom (listen_socket6,
                                           buf,
                                           size,
                                           (struct sockaddr *) &v6,
                                           &addrlen);
    if (0 > sret)
    {
      GNUNET_log_strerror (GNUNET_ERROR_TYPE_WARNING,
                           "recvfrom");
      return;
    }
    GNUNET_break (size != sret);
    handle_request (listen_socket6,
                    &v6,
                    addrlen,
                    buf,
                    size);
  }
}

References GNUNET_assert, GNUNET_break, GNUNET_ERROR_TYPE_WARNING, GNUNET_log_strerror, GNUNET_NETWORK_socket_recvfrom(), GNUNET_NETWORK_socket_recvfrom_amount(), GNUNET_SCHEDULER_add_read_net(), GNUNET_SCHEDULER_get_task_context(), GNUNET_SCHEDULER_REASON_READ_READY, GNUNET_TIME_UNIT_FOREVER_REL, handle_request(), listen_socket6, read_dns6(), GNUNET_SCHEDULER_TaskContext::reason, size, t6, and tc.

Referenced by read_dns6(), and run().

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◆ run()

static void run	(	void *	cls,
		char const	args,
		const char *	cfgfile,
		const struct GNUNET_CONFIGURATION_Handle *	c
	)

static

Main function that will be run.

Parameters

cls	closure
args	remaining command-line arguments
cfgfile	name of the configuration file used (for saving, can be NULL!)
c	configuration

Definition at line 824 of file gnunet-dns2gns.c.

{
  char *addr_str;
 
  (void) cls;
  (void) args;
  (void) cfgfile;
  cfg = c;
  if (NULL == dns_ip)
  {
    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
                _ ("No DNS server specified!\n"));
    return;
  }
  GNUNET_SCHEDULER_add_shutdown (&do_shutdown,
                                 NULL);
  if (NULL == (gns = GNUNET_GNS_connect (cfg)))
    return;
  if (NULL == (vpn_handle = GNUNET_VPN_connect (cfg)))
    return;
  GNUNET_assert (NULL != (dns_stub = GNUNET_DNSSTUB_start (128)));
  if (GNUNET_OK !=
      GNUNET_DNSSTUB_add_dns_ip (dns_stub,
                                 dns_ip))
  {
    GNUNET_DNSSTUB_stop (dns_stub);
    GNUNET_GNS_disconnect (gns);
    gns = NULL;
    GNUNET_VPN_disconnect (vpn_handle);
    vpn_handle = NULL;
    return;
  }
 
  /* Get address to bind to */
  if (GNUNET_OK != GNUNET_CONFIGURATION_get_value_string (c, "dns2gns",
                                                          "BIND_TO",
                                                          &addr_str))
  {
    // No address specified
    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
                "Don't know what to bind to...\n");
    GNUNET_free (addr_str);
    GNUNET_SCHEDULER_shutdown ();
    return;
  }
  if (1 != inet_pton (AF_INET, addr_str, &address))
  {
    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
                "Unable to parse address %s\n",
                addr_str);
    GNUNET_free (addr_str);
    GNUNET_SCHEDULER_shutdown ();
    return;
  }
  GNUNET_free (addr_str);
  /* Get address to bind to */
  if (GNUNET_OK != GNUNET_CONFIGURATION_get_value_string (c, "dns2gns",
                                                          "BIND_TO6",
                                                          &addr_str))
  {
    // No address specified
    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
                "Don't know what to bind6 to...\n");
    GNUNET_free (addr_str);
    GNUNET_SCHEDULER_shutdown ();
    return;
  }
  if (1 != inet_pton (AF_INET6, addr_str, &address6))
  {
    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
                "Unable to parse IPv6 address %s\n",
                addr_str);
    GNUNET_free (addr_str);
    GNUNET_SCHEDULER_shutdown ();
    return;
  }
  GNUNET_free (addr_str);
  if (GNUNET_OK == GNUNET_CONFIGURATION_get_value_number (c, "dns2gns",
                                                          "PORT",
                                                          &listen_port))
    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
                "Listening on %llu\n", listen_port);
 
  listen_socket4 = GNUNET_NETWORK_socket_create (PF_INET,
                                                 SOCK_DGRAM,
                                                 IPPROTO_UDP);
  if (NULL != listen_socket4)
  {
    struct sockaddr_in v4;
 
    memset (&v4, 0, sizeof(v4));
    v4.sin_family = AF_INET;
    v4.sin_addr.s_addr = address;
#if HAVE_SOCKADDR_IN_SIN_LEN
    v4.sin_len = sizeof(v4);
#endif
    v4.sin_port = htons (listen_port);
    if (GNUNET_OK !=
        GNUNET_NETWORK_socket_bind (listen_socket4,
                                    (struct sockaddr *) &v4,
                                    sizeof(v4)))
    {
      GNUNET_log_strerror (GNUNET_ERROR_TYPE_ERROR, "bind");
      GNUNET_NETWORK_socket_close (listen_socket4);
      listen_socket4 = NULL;
    }
  }
  listen_socket6 = GNUNET_NETWORK_socket_create (PF_INET6,
                                                 SOCK_DGRAM,
                                                 IPPROTO_UDP);
  if (NULL != listen_socket6)
  {
    struct sockaddr_in6 v6;
 
    memset (&v6, 0, sizeof(v6));
    v6.sin6_family = AF_INET6;
    v6.sin6_addr = address6;
#if HAVE_SOCKADDR_IN_SIN_LEN
    v6.sin6_len = sizeof(v6);
#endif
    v6.sin6_port = htons (listen_port);
    if (GNUNET_OK !=
        GNUNET_NETWORK_socket_bind (listen_socket6,
                                    (struct sockaddr *) &v6,
                                    sizeof(v6)))
    {
      GNUNET_log_strerror (GNUNET_ERROR_TYPE_ERROR, "bind");
      GNUNET_NETWORK_socket_close (listen_socket6);
      listen_socket6 = NULL;
    }
  }
  if ((NULL == listen_socket4) &&
      (NULL == listen_socket6))
  {
    GNUNET_GNS_disconnect (gns);
    gns = NULL;
    GNUNET_VPN_disconnect (vpn_handle);
    vpn_handle = NULL;
    GNUNET_DNSSTUB_stop (dns_stub);
    dns_stub = NULL;
    return;
  }
  if (NULL != listen_socket4)
    t4 = GNUNET_SCHEDULER_add_read_net (GNUNET_TIME_UNIT_FOREVER_REL,
                                        listen_socket4,
                                        &read_dns4,
                                        listen_socket4);
  if (NULL != listen_socket6)
    t6 = GNUNET_SCHEDULER_add_read_net (GNUNET_TIME_UNIT_FOREVER_REL,
                                        listen_socket6,
                                        &read_dns6,
                                        listen_socket6);
}

References _, address, address6, cfg, dns_ip, dns_stub, do_shutdown, gns, GNUNET_assert, GNUNET_CONFIGURATION_get_value_number(), GNUNET_CONFIGURATION_get_value_string(), GNUNET_DNSSTUB_add_dns_ip(), GNUNET_DNSSTUB_start(), GNUNET_DNSSTUB_stop(), GNUNET_ERROR_TYPE_DEBUG, GNUNET_ERROR_TYPE_ERROR, GNUNET_free, GNUNET_GNS_connect(), GNUNET_GNS_disconnect(), GNUNET_log, GNUNET_log_strerror, GNUNET_NETWORK_socket_bind(), GNUNET_NETWORK_socket_close(), GNUNET_NETWORK_socket_create(), GNUNET_OK, GNUNET_SCHEDULER_add_read_net(), GNUNET_SCHEDULER_add_shutdown(), GNUNET_SCHEDULER_shutdown(), GNUNET_TIME_UNIT_FOREVER_REL, GNUNET_VPN_connect(), GNUNET_VPN_disconnect(), listen_port, listen_socket4, listen_socket6, read_dns4(), read_dns6(), t4, t6, and vpn_handle.

Referenced by main().

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◆ main()

int main	(	int	argc,
		char const	argv
	)

The main function for the dns2gns daemon.

Parameters

argc	number of arguments from the command line
argv	command line arguments

Returns: 0 ok, 1 on error

Definition at line 990 of file gnunet-dns2gns.c.

{
  struct GNUNET_GETOPT_CommandLineOption options[] = {
    GNUNET_GETOPT_option_string ('d',
                                 "dns",
                                 "IP",
                                 gettext_noop (
                                   "IP of recursive DNS resolver to use (required)"),
                                 &dns_ip),
    GNUNET_GETOPT_OPTION_END
  };
  int ret;
 
  GNUNET_log_setup ("gnunet-dns2gns",
                    "WARNING",
                    NULL);
  ret =
    (GNUNET_OK ==
     GNUNET_PROGRAM_run (GNUNET_OS_project_data_gnunet (),
                         argc, argv,
                         "gnunet-dns2gns",
                         _ ("GNUnet DNS-to-GNS proxy (a DNS server)"),
                         options,
                         &run, NULL)) ? 0 : 1;
  return ret;
}

References _, dns_ip, gettext_noop, GNUNET_GETOPT_OPTION_END, GNUNET_GETOPT_option_string(), GNUNET_log_setup(), GNUNET_OK, GNUNET_OS_project_data_gnunet(), GNUNET_PROGRAM_run(), options, ret, and run().

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Variable Documentation

◆ address

in_addr_t address

static

The address to bind to.

Definition at line 142 of file gnunet-dns2gns.c.

Referenced by run().

◆ address6

struct in6_addr address6

static

The IPv6 address to bind to.

Definition at line 147 of file gnunet-dns2gns.c.

Referenced by run().

◆ gns

struct GNUNET_GNS_Handle* gns

Handle to GNS resolver.

Definition at line 153 of file gnunet-dns2gns.c.

Referenced by do_shutdown(), handle_request(), and run().

◆ vpn_handle

struct GNUNET_VPN_Handle* vpn_handle

static

Our handle to the vpn service.

Definition at line 158 of file gnunet-dns2gns.c.

Referenced by do_shutdown(), result_processor(), and run().

◆ dns_stub

struct GNUNET_DNSSTUB_Context* dns_stub

Stub resolver.

Definition at line 163 of file gnunet-dns2gns.c.

Referenced by do_shutdown(), result_processor(), and run().

◆ listen_socket4

struct GNUNET_NETWORK_Handle* listen_socket4

static

Listen socket for IPv4.

Definition at line 168 of file gnunet-dns2gns.c.

Referenced by do_shutdown(), read_dns4(), and run().

◆ listen_socket6

struct GNUNET_NETWORK_Handle* listen_socket6

static

Listen socket for IPv6.

Definition at line 173 of file gnunet-dns2gns.c.

Referenced by do_shutdown(), read_dns6(), and run().

◆ t4

struct GNUNET_SCHEDULER_Task* t4

static

Task for IPv4 socket.

Definition at line 178 of file gnunet-dns2gns.c.

Referenced by do_shutdown(), read_dns4(), and run().

◆ t6

struct GNUNET_SCHEDULER_Task* t6

static

Task for IPv6 socket.

Definition at line 183 of file gnunet-dns2gns.c.

Referenced by do_shutdown(), read_dns6(), and run().

◆ dns_ip

char* dns_ip

static

IP of DNS server.

Definition at line 188 of file gnunet-dns2gns.c.

Referenced by GNUNET_DNSSTUB_add_dns_ip(), main(), result_processor(), and run().

◆ listen_port

unsigned long long listen_port = 53

static

UDP Port we listen on for inbound DNS requests.

Definition at line 193 of file gnunet-dns2gns.c.

Referenced by run().

◆ cfg

const struct GNUNET_CONFIGURATION_Handle* cfg

static

Configuration to use.

Definition at line 198 of file gnunet-dns2gns.c.

Referenced by run().

Data Structures

Macros

Functions

Variables

Detailed Description

Macro Definition Documentation

◆ TIMEOUT

◆ VPN_TIMEOUT

Function Documentation

◆ do_shutdown()

◆ shuffle_answers()

◆ send_response()

◆ do_timeout()

◆ dns_result_processor()

◆ vpn_allocation_cb()

◆ result_processor()

◆ handle_request()

◆ read_dns4()

◆ read_dns6()

◆ run()

◆ main()

Variable Documentation

◆ address

◆ address6

◆ gns

◆ vpn_handle

◆ dns_stub

◆ listen_socket4

◆ listen_socket6

◆ t4

◆ t6

◆ dns_ip

◆ listen_port

◆ cfg