gnunet-dns-monitor.c File Reference

#include "platform.h"
#include "gnunet_util_lib.h"
#include "gnunet_dns_service.h"

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Functions
static const char *	get_type (uint16_t type)
	Convert numeric DNS record type to a string. More...
static const char *	get_class (uint16_t class)
	Convert numeric DNS record class to a string. More...
static void	display_query (const struct GNUNET_DNSPARSER_Query *query)
	Output the given DNS query to stdout. More...
static void	display_record (const struct GNUNET_DNSPARSER_Record *record)
	Output the given DNS record to stdout. More...
static void	display_request (void *cls, struct GNUNET_DNS_RequestHandle *rh, size_t request_length, const char *request)
	Signature of a function that is called whenever the DNS service encounters a DNS request and needs to do something with it. More...
static void	do_disconnect (void *cls)
	Shutdown. More...
static void	run (void *cls, char *const *args, const char *cfgfile, const struct GNUNET_CONFIGURATION_Handle *cfg)
	Main function that will be run by the scheduler. More...
int	main (int argc, char *const *argv)

Variables
static struct GNUNET_DNS_Handle *	handle
	Handle to transport service. More...
static int	inbound_only
	Option -i. More...
static int	outbound_only
	Option -o. More...
static int	ret
	Global return value (0 success). More...
static unsigned int	verbosity
	Selected level of verbosity. More...

Function Documentation

get_type()

static const char * get_type ( uint16_t  type )

static

Convert numeric DNS record type to a string.

Parameters

type	type to convert

Returns

type as string, only valid until the next call to this function

Definition at line 64 of file gnunet-dns-monitor.c.

{
  static char buf[6];
 
  switch (type)
  {
  case GNUNET_DNSPARSER_TYPE_A: return "A";
 
  case GNUNET_DNSPARSER_TYPE_NS: return "NS";
 
  case GNUNET_DNSPARSER_TYPE_CNAME: return "CNAME";
 
  case GNUNET_DNSPARSER_TYPE_SOA: return "SOA";
 
  case GNUNET_DNSPARSER_TYPE_PTR: return "PTR";
 
  case GNUNET_DNSPARSER_TYPE_MX: return "MX";
 
  case GNUNET_DNSPARSER_TYPE_TXT: return "TXT";
 
  case GNUNET_DNSPARSER_TYPE_AAAA: return "AAAA";
 
  case GNUNET_DNSPARSER_TYPE_SRV: return "SRV";
 
  case GNUNET_DNSPARSER_TYPE_URI: return "URI";
  }
  GNUNET_snprintf (buf, sizeof(buf), "%u", (unsigned int) type);
  return buf;
}

References GNUNET_DNSPARSER_TYPE_A, GNUNET_DNSPARSER_TYPE_AAAA, GNUNET_DNSPARSER_TYPE_CNAME, GNUNET_DNSPARSER_TYPE_MX, GNUNET_DNSPARSER_TYPE_NS, GNUNET_DNSPARSER_TYPE_PTR, GNUNET_DNSPARSER_TYPE_SOA, GNUNET_DNSPARSER_TYPE_SRV, GNUNET_DNSPARSER_TYPE_TXT, GNUNET_DNSPARSER_TYPE_URI, GNUNET_snprintf(), and type.

Referenced by display_query(), and display_record().

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get_class()

static const char * get_class ( uint16_t  class )

static

Convert numeric DNS record class to a string.

Parameters

class

class to convert

Returns

class as string, only valid until the next call to this function

Definition at line 102 of file gnunet-dns-monitor.c.

{
  static char buf[6];
 
  switch (class)
  {
  case GNUNET_TUN_DNS_CLASS_INTERNET: return "IN";
 
  case GNUNET_TUN_DNS_CLASS_CHAOS: return "CHAOS";
 
  case GNUNET_TUN_DNS_CLASS_HESIOD: return "HESIOD";
  }
  GNUNET_snprintf (buf, sizeof(buf), "%u", (unsigned int) class);
  return buf;
}

References GNUNET_snprintf(), GNUNET_TUN_DNS_CLASS_CHAOS, GNUNET_TUN_DNS_CLASS_HESIOD, and GNUNET_TUN_DNS_CLASS_INTERNET.

Referenced by display_query(), and display_record().

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display_query()

static void display_query ( const struct GNUNET_DNSPARSER_Query *  query )

static

Output the given DNS query to stdout.

Parameters

query

query to display.

Definition at line 125 of file gnunet-dns-monitor.c.

{
  fprintf (stdout,
           "\t\t%s %s: %s\n",
           get_class (query->dns_traffic_class),
           get_type (query->type),
           query->name);
}

References GNUNET_DNSPARSER_Query::dns_traffic_class, get_class(), get_type(), GNUNET_DNSPARSER_Query::name, and GNUNET_DNSPARSER_Query::type.

Referenced by display_request().

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display_record()

static void display_record ( const struct GNUNET_DNSPARSER_Record *  record )

static

Output the given DNS record to stdout.

Parameters

record

record to display.

Definition at line 141 of file gnunet-dns-monitor.c.

{
  const char *format;
  char buf[INET6_ADDRSTRLEN];
  char *tmp;
 
  tmp = NULL;
  switch (record->type)
  {
  case GNUNET_DNSPARSER_TYPE_A:
    if (record->data.raw.data_len != sizeof(struct in_addr))
      format = "<invalid>";
    else
      format = inet_ntop (AF_INET, record->data.raw.data, buf, sizeof(buf));
    break;
 
  case GNUNET_DNSPARSER_TYPE_AAAA:
    if (record->data.raw.data_len != sizeof(struct in6_addr))
      format = "<invalid>";
    else
      format = inet_ntop (AF_INET6, record->data.raw.data, buf, sizeof(buf));
    break;
 
  case GNUNET_DNSPARSER_TYPE_NS:
  case GNUNET_DNSPARSER_TYPE_CNAME:
  case GNUNET_DNSPARSER_TYPE_PTR:
    format = record->data.hostname;
    break;
 
  case GNUNET_DNSPARSER_TYPE_SOA:
    if (NULL == record->data.soa)
      format = "<invalid>";
    else
    {
      GNUNET_asprintf (&tmp,
                       "origin: %s, mail: %s, serial = %u, refresh = %u s, retry = %u s, expire = %u s, minimum = %u s",
                       record->data.soa->mname,
                       record->data.soa->rname,
                       (unsigned int) record->data.soa->serial,
                       (unsigned int) record->data.soa->refresh,
                       (unsigned int) record->data.soa->retry,
                       (unsigned int) record->data.soa->expire,
                       (unsigned int) record->data.soa->minimum_ttl);
      format = tmp;
    }
    break;
 
  case GNUNET_DNSPARSER_TYPE_MX:
    if (record->data.mx == NULL)
      format = "<invalid>";
    else
    {
      GNUNET_asprintf (&tmp,
                       "%u: %s",
                       record->data.mx->preference,
                       record->data.mx->mxhost);
      format = tmp;
    }
    break;
 
  case GNUNET_DNSPARSER_TYPE_SRV:
    if (NULL == record->data.srv)
      format = "<invalid>";
    else
    {
      GNUNET_asprintf (&tmp,
                       "priority %u, weight = %u, port = %u, target = %s",
                       (unsigned int) record->data.srv->priority,
                       (unsigned int) record->data.srv->weight,
                       (unsigned int) record->data.srv->port,
                       record->data.srv->target);
      format = tmp;
    }
    break;
 
  case GNUNET_DNSPARSER_TYPE_URI:
    if (NULL == record->data.uri)
      format = "<invalid>";
    else
    {
      GNUNET_asprintf (&tmp,
                       "priority %u, weight = %u, target = \"%s\"",
                       (unsigned int) record->data.uri->priority,
                       (unsigned int) record->data.uri->weight,
                       record->data.uri->target);
      format = tmp;
    }
    break;
 
 
  case GNUNET_DNSPARSER_TYPE_TXT:
    GNUNET_asprintf (&tmp,
                     "%.*s",
                     (unsigned int) record->data.raw.data_len,
                     (char*) record->data.raw.data);
    format = tmp;
    break;
 
  default:
    format = "<payload>";
    break;
  }
  fprintf (stdout,
           "\t\t%s %s: %s = %s (%u s)\n",
           get_class (record->dns_traffic_class),
           get_type (record->type),
           record->name,
           format,
           (unsigned int) (GNUNET_TIME_absolute_get_remaining (
                             record->expiration_time).rel_value_us / 1000LL
                           / 1000LL));
  GNUNET_free (tmp);
}

References get_class(), get_type(), GNUNET_asprintf(), GNUNET_DNSPARSER_TYPE_A, GNUNET_DNSPARSER_TYPE_AAAA, GNUNET_DNSPARSER_TYPE_CNAME, GNUNET_DNSPARSER_TYPE_MX, GNUNET_DNSPARSER_TYPE_NS, GNUNET_DNSPARSER_TYPE_PTR, GNUNET_DNSPARSER_TYPE_SOA, GNUNET_DNSPARSER_TYPE_SRV, GNUNET_DNSPARSER_TYPE_TXT, GNUNET_DNSPARSER_TYPE_URI, GNUNET_free, GNUNET_TIME_absolute_get_remaining(), record(), and GNUNET_TIME_Relative::rel_value_us.

Referenced by display_request().

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display_request()

static void display_request ( void *  cls, struct GNUNET_DNS_RequestHandle *  rh, size_t  request_length, const char *  request  )

static

Signature of a function that is called whenever the DNS service encounters a DNS request and needs to do something with it.

The function has then the chance to generate or modify the response by calling one of the three "GNUNET_DNS_request_*" continuations.

When a request is intercepted, this function is called first to give the client a chance to do the complete address resolution; "rdata" will be NULL for this first call for a DNS request, unless some other client has already filled in a response.

If multiple clients exist, all of them are called before the global DNS. The global DNS is only called if all of the clients' functions call GNUNET_DNS_request_forward. Functions that call GNUNET_DNS_request_forward will be called again before a final response is returned to the application. If any of the clients' functions call GNUNET_DNS_request_drop, the response is dropped.

Parameters

cls	closure
rh	request handle to user for reply
request_length	number of bytes in request
request	udp payload of the DNS request

Definition at line 280 of file gnunet-dns-monitor.c.

{
  static const char *return_codes[] = {
    "No error", "Format error", "Server failure", "Name error",
    "Not implemented", "Refused", "YXDomain", "YXRRset",
    "NXRRset", "NOT AUTH", "NOT ZONE", "<invalid>",
    "<invalid>", "<invalid>", "<invalid>", "<invalid>"
  };
  static const char *op_codes[] = {
    "Query", "Inverse query", "Status", "<invalid>",
    "<invalid>", "<invalid>", "<invalid>", "<invalid>",
    "<invalid>", "<invalid>", "<invalid>", "<invalid>",
    "<invalid>", "<invalid>", "<invalid>", "<invalid>"
  };
  struct GNUNET_DNSPARSER_Packet *p;
  unsigned int i;
 
  p = GNUNET_DNSPARSER_parse (request, request_length);
  if (NULL == p)
  {
    fprintf (stderr, "Received malformed DNS packet!\n");
    // FIXME: drop instead?
    GNUNET_DNS_request_forward (rh);
    return;
  }
  fprintf (stdout,
           "%s with ID: %5u Flags: %s%s%s%s%s%s, Return Code: %s, Opcode: %s\n",
           p->flags.query_or_response ? "Response" : "Query",
           p->id,
           p->flags.recursion_desired ? "RD " : "",
           p->flags.message_truncated ? "MT " : "",
           p->flags.authoritative_answer ? "AA " : "",
           p->flags.checking_disabled ? "CD " : "",
           p->flags.authenticated_data ? "AD " : "",
           p->flags.recursion_available ? "RA " : "",
           return_codes[p->flags.return_code & 15],
           op_codes[p->flags.opcode & 15]);
  if (p->num_queries > 0)
    fprintf (stdout,
             "\tQueries:\n");
  for (i = 0; i < p->num_queries; i++)
    display_query (&p->queries[i]);
 
  if (p->num_answers > 0)
    fprintf (stdout,
             "\tAnswers:\n");
  for (i = 0; i < p->num_answers; i++)
    display_record (&p->answers[i]);
  fprintf (stdout, "\n");
  GNUNET_DNSPARSER_free_packet (p);
  GNUNET_DNS_request_forward (rh);
}

References display_query(), display_record(), GNUNET_DNS_request_forward(), GNUNET_DNSPARSER_free_packet(), GNUNET_DNSPARSER_parse(), p, and request.

Referenced by run().

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do_disconnect()

static void do_disconnect ( void *  cls )

static

Shutdown.

Definition at line 341 of file gnunet-dns-monitor.c.

{
  if (NULL != handle)
  {
    GNUNET_DNS_disconnect (handle);
    handle = NULL;
  }
}

References GNUNET_DNS_disconnect(), and handle.

Referenced by run().

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run()

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

static

Main function that will be run by the scheduler.

Parameters

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

Definition at line 360 of file gnunet-dns-monitor.c.

{
  enum GNUNET_DNS_Flags flags;
 
  flags = GNUNET_DNS_FLAG_REQUEST_MONITOR | GNUNET_DNS_FLAG_RESPONSE_MONITOR;
  if (inbound_only | outbound_only)
    flags = 0;
  if (inbound_only)
    flags |= GNUNET_DNS_FLAG_REQUEST_MONITOR;
  if (outbound_only)
    flags |= GNUNET_DNS_FLAG_RESPONSE_MONITOR;
  handle =
    GNUNET_DNS_connect (cfg,
                        flags,
                        &display_request,
                        NULL);
  GNUNET_SCHEDULER_add_shutdown (&do_disconnect, NULL);
}

References cfg, display_request(), do_disconnect(), GNUNET_DNSPARSER_Packet::flags, GNUNET_DNS_connect(), GNUNET_DNS_FLAG_REQUEST_MONITOR, GNUNET_DNS_FLAG_RESPONSE_MONITOR, GNUNET_SCHEDULER_add_shutdown(), handle, inbound_only, and outbound_only.

Referenced by main().

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main()

int main	(	int	argc,
		char *const *	argv
	)

Definition at line 382 of file gnunet-dns-monitor.c.

{
  struct GNUNET_GETOPT_CommandLineOption options[] = {
    GNUNET_GETOPT_option_flag ('i',
                               "inbound-only",
                               gettext_noop ("only monitor DNS queries"),
                               &inbound_only),
 
    GNUNET_GETOPT_option_flag ('o',
                               "outbound-only",
                               gettext_noop ("only monitor DNS queries"),
                               &outbound_only),
 
    GNUNET_GETOPT_option_verbose (&verbosity),
    GNUNET_GETOPT_OPTION_END
  };
 
  ret = (GNUNET_OK ==
         GNUNET_PROGRAM_run (GNUNET_OS_project_data_gnunet (),
                             argc, argv, "gnunet-dns-monitor",
                             gettext_noop
                               ("Monitor DNS queries."), options,
                             &run, NULL)) ? ret : 1;
  return ret;
}

References gettext_noop, GNUNET_GETOPT_OPTION_END, GNUNET_GETOPT_option_flag(), GNUNET_GETOPT_option_verbose(), GNUNET_OK, GNUNET_OS_project_data_gnunet(), GNUNET_PROGRAM_run(), inbound_only, options, outbound_only, ret, run(), and verbosity.

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Variable Documentation

handle

struct GNUNET_DNS_Handle* handle

static

Handle to transport service.

Definition at line 34 of file gnunet-dns-monitor.c.

Referenced by do_disconnect(), and run().

inbound_only

int inbound_only

static

Option -i.

Definition at line 39 of file gnunet-dns-monitor.c.

Referenced by main(), and run().

outbound_only

int outbound_only

static

Option -o.

Definition at line 44 of file gnunet-dns-monitor.c.

Referenced by main(), and run().

ret

int ret

static

Global return value (0 success).

Definition at line 49 of file gnunet-dns-monitor.c.

Referenced by main().

verbosity

unsigned int verbosity

static

Selected level of verbosity.

Definition at line 54 of file gnunet-dns-monitor.c.

Referenced by main().