1 files changed, 256 insertions, 0 deletions
diff --git a/src/extensions/age_restriction/age_restriction.c b/src/extensions/age_restriction/age_restriction.c
new file mode 100644
index 000000000..08b598d50
--- /dev/null
+++ b/src/extensions/age_restriction/age_restriction.c
@@ -0,0 +1,256 @@
+/*
+   This file is part of TALER
+   Copyright (C) 2021-2022 Taler Systems SA
+
+   TALER 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.
+
+   TALER 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
+   TALER; see the file COPYING.  If not, see <http://www.gnu.org/licenses/>
+ */
+/**
+ * @file age_restriction.c
+ * @brief Utility functions regarding age restriction
+ * @author Özgür Kesim
+ */
+#include "platform.h"
+#include "taler_util.h"
+#include "taler_extensions.h"
+#include "stdint.h"
+
+/* ==================================================
+ *
+ * Age Restriction  TALER_Extension implementation
+ *
+ * ==================================================
+ */
+
+/**
+ * @brief local configuration
+ */
+
+static struct TALER_AgeRestrictionConfig AR_config = {0};
+
+/**
+ * @brief implements the TALER_Extension.disable interface.
+ *
+ * @param ext Pointer to the current extension
+ */
+static void
+age_restriction_disable (
+  struct TALER_Extension *ext)
+{
+  if (NULL == ext)
+    return;
+
+  ext->enabled = false;
+  ext->config = NULL;
+
+  AR_config.mask.bits = 0;
+  AR_config.num_groups = 0;
+}
+
+
+/**
+ * @brief implements the TALER_Extension.load_config interface.
+ *
+ * @param ext if NULL, only tests the configuration
+ * @param jconfig the configuration as json
+ */
+static enum GNUNET_GenericReturnValue
+age_restriction_load_config (
+  const json_t *jconfig,
+  struct TALER_Extension *ext)
+{
+  struct TALER_AgeMask mask = {0};
+  enum GNUNET_GenericReturnValue ret;
+
+  ret = TALER_JSON_parse_age_groups (jconfig, &mask);
+  if (GNUNET_OK != ret)
+    return ret;
+
+  /* only testing the parser */
+  if (ext == NULL)
+    return GNUNET_OK;
+
+  if (TALER_Extension_AgeRestriction != ext->type)
+    return GNUNET_SYSERR;
+
+  if (mask.bits > 0)
+  {
+    /* if the mask is not zero, the first bit MUST be set */
+    if (0 == (mask.bits & 1))
+      return GNUNET_SYSERR;
+
+    AR_config.mask.bits = mask.bits;
+    AR_config.num_groups = __builtin_popcount (mask.bits) - 1;
+  }
+
+  ext->config = &AR_config;
+  ext->enabled = true;
+
+  GNUNET_log (GNUNET_ERROR_TYPE_INFO,
+              "loaded new age restriction config with age groups: %s\n",
+              TALER_age_mask_to_string (&mask));
+
+  return GNUNET_OK;
+}
+
+
+/**
+ * @brief implements the TALER_Extension.manifest interface.
+ *
+ * @param ext if NULL, only tests the configuration
+ * @return configuration as json_t* object, maybe NULL
+ */
+static json_t *
+age_restriction_manifest (
+  const struct TALER_Extension *ext)
+{
+  json_t *conf;
+
+  GNUNET_assert (NULL != ext);
+
+  if (NULL == ext->config)
+  {
+    GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
+                "age restriction not configured");
+    return json_null ();
+  }
+
+  conf = GNUNET_JSON_PACK (
+    GNUNET_JSON_pack_string ("age_groups",
+                             TALER_age_mask_to_string (&AR_config.mask))
+    );
+  return GNUNET_JSON_PACK (
+    GNUNET_JSON_pack_bool ("critical",
+                           ext->critical),
+    GNUNET_JSON_pack_string ("version",
+                             ext->version),
+    GNUNET_JSON_pack_object_steal ("config",
+                                   conf)
+    );
+}
+
+
+/* The extension for age restriction */
+struct TALER_Extension TE_age_restriction = {
+  .type = TALER_Extension_AgeRestriction,
+  .name = "age_restriction",
+  .critical = false,
+  .version = "1",
+  .enabled = false, /* disabled per default */
+  .config = NULL,
+  .disable = &age_restriction_disable,
+  .load_config = &age_restriction_load_config,
+  .manifest = &age_restriction_manifest,
+
+  /* This extension is not a policy extension */
+  .create_policy_details = NULL,
+  .policy_get_handler = NULL,
+  .policy_post_handler = NULL,
+};
+
+
+/**
+ * @brief implements the init() function for GNUNET_PLUGIN_load
+ *
+ * @param arg Pointer to the GNUNET_CONFIGURATION_Handle
+ * @return pointer to TALER_Extension on success or NULL otherwise.
+ */
+void *
+libtaler_extension_age_restriction_init (void *arg)
+{
+  const struct GNUNET_CONFIGURATION_Handle *cfg = arg;
+  char *groups = NULL;
+  struct TALER_AgeMask mask = {0};
+
+  if ((GNUNET_YES !=
+       GNUNET_CONFIGURATION_have_value (cfg,
+                                        TALER_EXTENSION_SECTION_AGE_RESTRICTION,
+                                        "ENABLED"))
+      ||
+      (GNUNET_YES !=
+       GNUNET_CONFIGURATION_get_value_yesno (cfg,
+                                             TALER_EXTENSION_SECTION_AGE_RESTRICTION,
+                                             "ENABLED")))
+  {
+    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+                "[age restriction] no section %s found in configuration\n",
+                TALER_EXTENSION_SECTION_AGE_RESTRICTION);
+
+    return NULL;
+  }
+
+  /* Age restriction is enabled, extract age groups */
+  if ((GNUNET_YES ==
+       GNUNET_CONFIGURATION_have_value (cfg,
+                                        TALER_EXTENSION_SECTION_AGE_RESTRICTION,
+                                        "AGE_GROUPS"))
+      &&
+      (GNUNET_YES !=
+       GNUNET_CONFIGURATION_get_value_string (cfg,
+                                              TALER_EXTENSION_SECTION_AGE_RESTRICTION,
+                                              "AGE_GROUPS",
+                                              &groups)))
+  {
+    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+                "[age restriction] AGE_GROUPS in %s is not a string\n",
+                TALER_EXTENSION_SECTION_AGE_RESTRICTION);
+
+    return NULL;
+  }
+
+  if (NULL == groups)
+    groups = GNUNET_strdup (TALER_EXTENSION_AGE_RESTRICTION_DEFAULT_AGE_GROUPS);
+
+  if (GNUNET_OK != TALER_parse_age_group_string (groups, &mask))
+  {
+    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+                "[age restriction] couldn't parse age groups: '%s'\n",
+                groups);
+    return NULL;
+  }
+
+  AR_config.mask = mask;
+  AR_config.num_groups = __builtin_popcount (mask.bits) - 1;   /* no underflow, first bit always set */
+
+  GNUNET_log (GNUNET_ERROR_TYPE_INFO,
+              "[age restriction] setting age mask to %s with #groups: %d\n",
+              TALER_age_mask_to_string (&AR_config.mask),
+              __builtin_popcount (AR_config.mask.bits) - 1);
+
+  TE_age_restriction.config = &AR_config;
+
+  /* Note: we do now have TE_age_restriction_config set, however the extension
+   * is not yet enabled! For age restriction to become active, load_config must
+   * have been called. */
+
+  GNUNET_free (groups);
+  return &TE_age_restriction;
+}
+
+
+/**
+ * @brief implements the done() function for GNUNET_PLUGIN_load
+ *
+ * @param arg unused
+ * @return pointer to TALER_Extension on success or NULL otherwise.
+ */
+void *
+libtaler_extension_age_restriction_done (void *arg)
+{
+  GNUNET_log (GNUNET_ERROR_TYPE_INFO,
+              "[age restriction] disabling and unloading");
+  AR_config.mask.bits = 0;
+  AR_config.num_groups = 0;
+  return NULL;
+}
+
+
+/* end of age_restriction.c */