/*
   This file is part of GNUnet.
   Copyright (C) 2009 GNUnet e.V.

   GNUnet is free software: you can redistribute it and/or modify it
   under the terms of the GNU Affero General Public License as published
   by the Free Software Foundation, either version 3 of the License,
   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
   Affero General Public License for more details.

   You should have received a copy of the GNU Affero General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.

     SPDX-License-Identifier: AGPL3.0-or-later
 */
/**
 * @file resolver/test_resolver_api.c
 * @brief testcase for resolver_api.c
 */
#include "platform.h"
#include "gnunet_util_lib.h"
#include "gnunet_resolver_service.h"
#include "resolver.h"


static int disable_rootserver_check;


/**
 * Using DNS root servers to check gnunet's resolver service
 * a.root-servers.net <-> 198.41.0.4 is a fix 1:1 mapping that should not change over years
 * For more information have a look at IANA's website http://www.root-servers.org/
 */
#define ROOTSERVER_NAME "a.root-servers.net"
#define ROOTSERVER_IP   "198.41.0.4"


static void
check_hostname (void *cls,
                const struct sockaddr *sa,
                socklen_t salen)
{
  int *ok = cls;

  if (0 == salen)
  {
    (*ok) &= ~8;
    return;
  }
  GNUNET_log (GNUNET_ERROR_TYPE_INFO,
              "Got IP address `%s' for our host.\n",
              GNUNET_a2s (sa, salen));
}


static void
check_localhost_num (void *cls,
                     const char *hostname)
{
  int *ok = cls;

  if (hostname == NULL)
    return;
  if (0 == strcmp (hostname, "127.0.0.1"))
  {
    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
                "Received correct hostname `%s'.\n",
                hostname);
    (*ok) &= ~4;
  }
  else
  {
    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
                "Received invalid hostname `%s'.\n",
                hostname);
    GNUNET_break (0);
  }
}


static void
check_localhost (void *cls,
                 const char *hostname)
{
  int *ok = cls;

  if (NULL == hostname)
    return;
  if (0 == strcmp (hostname, "localhost"))
  {
    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
                "Received correct hostname `%s'.\n",
                hostname);
    (*ok) &= ~2;
  }
  else
  {
    GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
                "Received unexpected hostname `%s', expected `localhost' (this could be OK).\n",
                hostname);
  }
}


static void
check_127 (void *cls, const struct sockaddr *sa, socklen_t salen)
{
  int *ok = cls;
  const struct sockaddr_in *sai = (const struct sockaddr_in *) sa;

  if (NULL == sa)
    return;
  GNUNET_assert (sizeof(struct sockaddr_in) == salen);
  if (sai->sin_addr.s_addr == htonl (INADDR_LOOPBACK))
  {
    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
                "Received correct address.\n");
    (*ok) &= ~1;
  }
  else
  {
    char buf[INET_ADDRSTRLEN];

    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
                "Received incorrect address `%s'.\n",
                inet_ntop (AF_INET,
                           &sai->sin_addr,
                           buf,
                           sizeof(buf)));
    GNUNET_break (0);
  }
}


static void
check_rootserver_ip (void *cls, const struct sockaddr *sa, socklen_t salen)
{
  int *ok = cls;
  const struct sockaddr_in *sai = (const struct sockaddr_in *) sa;

  if (NULL == sa)
    return;
  GNUNET_assert (sizeof(struct sockaddr_in) == salen);

  if (0 == strcmp (inet_ntoa (sai->sin_addr), ROOTSERVER_IP))
  {
    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
                "Received correct rootserver ip address.\n");
    (*ok) &= ~1;
  }
  else
  {
    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
                "Received incorrect rootserver ip address.\n");
    GNUNET_break (0);
  }
}


static void
check_rootserver_name (void *cls,
                       const char *hostname)
{
  int *ok = cls;

  if (NULL == hostname)
    return;

  if (0 == strcmp (hostname, ROOTSERVER_NAME))
  {
    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
                "Received correct rootserver hostname `%s'.\n",
                hostname);
    (*ok) &= ~2;
  }
  else
  {
    GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
                "Received invalid rootserver hostname `%s', expected `%s'\n",
                hostname,
                ROOTSERVER_NAME);
    GNUNET_break (disable_rootserver_check);
  }
}


static void
run (void *cls, char *const *args, const char *cfgfile,
     const struct GNUNET_CONFIGURATION_Handle *cfg)
{
  int *ok = cls;
  struct sockaddr_in sa;
  struct GNUNET_TIME_Relative timeout =
    GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_SECONDS, 30);
  int count_ips = 0;
  char *own_fqdn;
  const char *rootserver_name = ROOTSERVER_NAME;
  struct hostent *rootserver;
  struct in_addr rootserver_addr;

  memset (&sa, 0, sizeof(sa));
  sa.sin_family = AF_INET;
#if HAVE_SOCKADDR_IN_SIN_LEN
  sa.sin_len = (u_char) sizeof(sa);
#endif
  sa.sin_addr.s_addr = htonl (INADDR_LOOPBACK);

  /*
   * Looking up our own fqdn
   */
  own_fqdn = GNUNET_RESOLVER_local_fqdn_get ();
  /* can't really check, only thing we can safely
     compare against is our own identical logic... */
  GNUNET_free (own_fqdn);

  /*
   * Testing non-local DNS resolution
   * DNS rootserver to test: a.root-servers.net - 198.41.0.4
   */

  rootserver = gethostbyname (rootserver_name);
  if (NULL == rootserver)
  {
    /* Error: resolving ip addresses does not work */
    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
                _ ("gethostbyname() could not lookup IP address: %s\n"),
                hstrerror (h_errno));
    fprintf (stderr,
             "%s",
             "System seems to be off-line, will not run all DNS tests\n");
    *ok = 0;                    /* mark test as passing anyway */
    return;
  }

  /* Counting returned IP addresses */
  while (NULL != rootserver->h_addr_list[count_ips])
    count_ips++;
  if (count_ips > 1)
  {
    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
                "IP received range for root name server, but a root name server has only 1 IP\n");
    GNUNET_break (0);
  }

  /* Comparing to resolved address to the address the root name server should have */
  if (0 !=
      strcmp (inet_ntoa (*(struct in_addr *) rootserver->h_addr_list[0]),
              ROOTSERVER_IP))
  {
    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
                "IP received and IP for root name server differ\n");
    GNUNET_break (0);
  }
  GNUNET_log (GNUNET_ERROR_TYPE_INFO,
              "System's own forward name resolution is working\n");
  /* Resolve the same using GNUNET */
  GNUNET_RESOLVER_ip_get (ROOTSERVER_NAME, AF_INET, timeout,
                          &check_rootserver_ip, cls);
  GNUNET_RESOLVER_ip_get (ROOTSERVER_NAME, AF_INET, timeout,
                          &check_rootserver_ip, cls);

  /*
   * Success: forward lookups work as expected
   * Next step: reverse lookups
   */
  if (1 != inet_pton (AF_INET,
                      ROOTSERVER_IP,
                      &rootserver_addr))
  {
    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
                "Could not transform root name server IP address\n");
    GNUNET_break (0);
  }

  rootserver =
    gethostbyaddr ((const void *) &rootserver_addr,
                   sizeof(rootserver_addr),
                   AF_INET);
  if (NULL == rootserver)
  {
    /* Error: resolving IP addresses does not work */
    GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
                "gethostbyaddr() could not lookup hostname: %s\n",
                hstrerror (h_errno));
    disable_rootserver_check = GNUNET_YES;
  }
  else
  {
    if (0 != strcmp (rootserver->h_name,
                     ROOTSERVER_NAME))
    {
      GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
                  "Received hostname and hostname for root name server differ\n");
      disable_rootserver_check = GNUNET_YES;
    }
  }

  GNUNET_log (GNUNET_ERROR_TYPE_INFO,
              "System's own reverse name resolution is working\n");
  /* Resolve the same using GNUNET */
  memset (&sa, 0, sizeof(sa));
  sa.sin_family = AF_INET;
#if HAVE_SOCKADDR_IN_SIN_LEN
  sa.sin_len = (u_char) sizeof(sa);
#endif
  inet_aton (ROOTSERVER_IP, &sa.sin_addr);

  GNUNET_RESOLVER_hostname_get ((const struct sockaddr *) &sa,
                                sizeof(struct sockaddr), GNUNET_YES, timeout,
                                &check_rootserver_name, cls);

  memset (&sa, 0, sizeof(sa));
  sa.sin_family = AF_INET;
#if HAVE_SOCKADDR_IN_SIN_LEN
  sa.sin_len = (u_char) sizeof(sa);
#endif
  sa.sin_addr.s_addr = htonl (INADDR_LOOPBACK);

  GNUNET_RESOLVER_ip_get ("localhost", AF_INET, timeout, &check_127, cls);
  GNUNET_RESOLVER_hostname_get ((const struct sockaddr *) &sa,
                                sizeof(struct sockaddr), GNUNET_YES, timeout,
                                &check_localhost, cls);

  GNUNET_RESOLVER_hostname_get ((const struct sockaddr *) &sa,
                                sizeof(struct sockaddr), GNUNET_NO, timeout,
                                &check_localhost_num, cls);
  GNUNET_RESOLVER_hostname_resolve (AF_UNSPEC, timeout, &check_hostname, cls);
}


int
main (int argc, char *argv[])
{
  int ok = 1 + 2 + 4 + 8;
  char *fn;
  struct GNUNET_OS_Process *proc;
  char *const argvx[] = {
    "test-resolver-api", "-c", "test_resolver_api_data.conf", NULL
  };
  struct GNUNET_GETOPT_CommandLineOption options[] =
  { GNUNET_GETOPT_OPTION_END };

  GNUNET_log_setup ("test-resolver-api",
                    "WARNING",
                    NULL);
  fn = GNUNET_OS_get_libexec_binary_path ("gnunet-service-resolver");
  proc = GNUNET_OS_start_process (GNUNET_OS_INHERIT_STD_OUT_AND_ERR
                                  | GNUNET_OS_USE_PIPE_CONTROL,
                                  NULL, NULL, NULL,
                                  fn,
                                  "gnunet-service-resolver",
                                  "-c", "test_resolver_api_data.conf", NULL);
  GNUNET_assert (NULL != proc);
  GNUNET_free (fn);
  GNUNET_assert (GNUNET_OK ==
                 GNUNET_PROGRAM_run ((sizeof(argvx) / sizeof(char *)) - 1,
                                     argvx, "test-resolver-api", "nohelp",
                                     options, &run, &ok));
  if (0 != GNUNET_OS_process_kill (proc, GNUNET_TERM_SIG))
  {
    GNUNET_log_strerror (GNUNET_ERROR_TYPE_WARNING, "kill");
    ok = 1;
  }
  GNUNET_OS_process_wait (proc);
  GNUNET_OS_process_destroy (proc);
  proc = NULL;
  if (0 != ok)
    fprintf (stderr, "Missed some resolutions: %u\n", ok);
  return ok;
}


/* end of test_resolver_api.c */
