[age restriction] progress 8/n

More work towards support for extensions and age restriction

- updated gana
- added handler for DB-Event
- added TEH_extensions_init() and _done()
- added global for age restriction
- added stub for post handler
- added SQL-table for extension metadata
- added enum type for extensions and other data structures

Also:
- fixed some warnings -Wmaybe-unitialized

contrib/gana

@@ -1 +1 @@
-Subproject commit b123140349c3e3b300878d2e35cea1553c9a381d
+Subproject commit ce3c127a788d4bc35caf8472fa9799b45f8d2133

src/exchange/Makefile.am

@@ -82,6 +82,7 @@ taler_exchange_httpd_SOURCES = \
   taler-exchange-httpd_db.c taler-exchange-httpd_db.h \
   taler-exchange-httpd_deposit.c taler-exchange-httpd_deposit.h \
   taler-exchange-httpd_deposits_get.c taler-exchange-httpd_deposits_get.h \
+  taler-exchange-httpd_extensions.c taler-exchange-httpd_extensions.h \
   taler-exchange-httpd_keys.c taler-exchange-httpd_keys.h \
   taler-exchange-httpd_kyc-check.c taler-exchange-httpd_kyc-check.h \
   taler-exchange-httpd_kyc-proof.c taler-exchange-httpd_kyc-proof.h \
@@ -91,6 +92,7 @@ taler_exchange_httpd_SOURCES = \
   taler-exchange-httpd_management_auditors.c \
   taler-exchange-httpd_management_auditors_AP_disable.c \
   taler-exchange-httpd_management_denominations_HDP_revoke.c \
+  taler-exchange-httpd_management_extensions.c \
   taler-exchange-httpd_management_post_keys.c \
   taler-exchange-httpd_management_signkey_EP_revoke.c \
   taler-exchange-httpd_management_wire_enable.c \
@@ -109,9 +111,6 @@ taler_exchange_httpd_SOURCES = \
   taler-exchange-httpd_wire.c taler-exchange-httpd_wire.h \
   taler-exchange-httpd_withdraw.c taler-exchange-httpd_withdraw.h
 
-#  taler-exchange-httpd_management_post_keys.c
-
-
 taler_exchange_httpd_LDADD = \
   $(LIBGCRYPT_LIBS) \
   $(top_builddir)/src/bank-lib/libtalerbank.la \

src/exchange/taler-exchange-httpd.c

@@ -1799,7 +1799,8 @@ do_shutdown (void *cls)
   TEH_kyc_proof_cleanup ();
   if (NULL != mhd)
     MHD_stop_daemon (mhd);
-  TEH_WIRE_done ();
+  TEH_wire_done ();
+  TEH_extensions_done ();
   TEH_keys_finished ();
   if (NULL != TEH_plugin)
   {
@@ -1860,6 +1861,13 @@ run (void *cls,
     GNUNET_SCHEDULER_shutdown ();
     return;
   }
+  if (GNUNET_OK !=
+      TEH_extensions_init ())
+  {
+    global_ret = EXIT_FAILURE;
+    GNUNET_SCHEDULER_shutdown ();
+    return;
+  }
   if (GNUNET_OK !=
       TEH_keys_init ())
   {

src/exchange/taler-exchange-httpd_extensions.c

@@ -0,0 +1,110 @@
+/*
+  This file is part of TALER
+  Copyright (C) 2021 Taler Systems SA
+
+  TALER 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, 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 Affero General Public License for more details.
+  You should have received a copy of the GNU Affero General Public License along with
+  TALER; see the file COPYING.  If not, see <http://www.gnu.org/licenses/>
+*/
+/**
+ * @file taler-exchange-httpd_extensions.c
+ * @brief Handle extensions (age-restriction, peer2peer)
+ * @author Özgür Kesim
+ */
+#include "platform.h"
+#include <gnunet/gnunet_json_lib.h>
+#include "taler_dbevents.h"
+#include "taler-exchange-httpd_responses.h"
+#include "taler-exchange-httpd_extensions.h"
+#include "taler_json_lib.h"
+#include "taler_mhd_lib.h"
+#include <jansson.h>
+
+
+/**
+ * Handler listening for extensions updates by other exchange
+ * services.
+ */
+static struct GNUNET_DB_EventHandler *extensions_eh;
+
+
+/**
+ * Function called whenever another exchange process has updated
+ * the extensions data in the database.
+ *
+ * @param cls NULL
+ * @param extra unused
+ * @param extra_size number of bytes in @a extra unused
+ */
+static void
+extension_update_event_cb (void *cls,
+                           const void *extra,
+                           size_t extra_size)
+{
+  (void) cls;
+  (void) extra;
+  (void) extra_size;
+  GNUNET_log (GNUNET_ERROR_TYPE_INFO,
+              "Received /management/extensions update event\n");
+}
+
+
+enum GNUNET_GenericReturnValue
+TEH_extensions_init ()
+{
+  struct GNUNET_DB_EventHeaderP es = {
+    .size = htons (sizeof (es)),
+    .type = htons (TALER_DBEVENT_EXCHANGE_EXTENSIONS_UPDATED),
+  };
+
+  extensions_eh = TEH_plugin->event_listen (TEH_plugin->cls,
+                                            GNUNET_TIME_UNIT_FOREVER_REL,
+                                            &es,
+                                            &extension_update_event_cb,
+                                            NULL);
+  if (NULL == extensions_eh)
+  {
+    GNUNET_break (0);
+    return GNUNET_SYSERR;
+  }
+  return GNUNET_OK;
+}
+
+
+void
+TEH_extensions_done ()
+{
+  if (NULL != extensions_eh)
+  {
+    TEH_plugin->event_listen_cancel (TEH_plugin->cls,
+                                     extensions_eh);
+    extensions_eh = NULL;
+  }
+}
+
+
+void
+TEH_extensions_update_state (void)
+{
+  /* TODO */
+#if 0
+  struct GNUNET_DB_EventHeaderP es = {
+    .size = htons (sizeof (es)),
+    .type = htons (TALER_DBEVENT_EXCHANGE_WIRE_UPDATED),
+  };
+
+  TEH_plugin->event_notify (TEH_plugin->cls,
+                            &es,
+                            NULL,
+                            0);
+#endif
+}
+
+
+/* end of taler-exchange-httpd_extensions.c */

src/exchange/taler-exchange-httpd_extensions.h

@@ -0,0 +1,51 @@
+/*
+  This file is part of TALER
+  Copyright (C) 2021 Taler Systems SA
+
+  TALER 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, 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 Affero General Public License for more details.
+
+  You should have received a copy of the GNU Affero General Public License along with
+  TALER; see the file COPYING.  If not, see <http://www.gnu.org/licenses/>
+*/
+/**
+ * @file taler-exchange-httpd_extensions.h
+ * @brief Manage extensions
+ * @author Özgür Kesim
+ */
+#ifndef TALER_EXCHANGE_HTTPD_EXTENSIONS_H
+#define TALER_EXCHANGE_HTTPD_EXTENSIONS_H
+
+#include <gnunet/gnunet_util_lib.h>
+#include <microhttpd.h>
+#include "taler-exchange-httpd.h"
+
+
+/**
+ * Initialize extensions
+ *
+ * @return #GNUNET_OK on success
+ */
+enum GNUNET_GenericReturnValue
+TEH_extensions_init (void);
+
+/**
+ * Terminate the extension subsystem
+ */
+void
+TEH_extensions_done (void);
+
+/**
+ * Something changed in the database. Rebuild the extension state metadata.
+ * This function should be called if the exchange learns about a new signature
+ * from our master key.
+ */
+void
+TEH_extensions_update_state (void);
+
+#endif

src/exchange/taler-exchange-httpd_keys.c

@@ -750,7 +750,7 @@ load_age_mask (const char*section_name)
   struct TALER_AgeMask age_mask = {0};
 
   /* FIXME-oec: get age_mask from database, not from config */
-  if (TALER_EXTENSION_OK != TALER_get_age_mask (TEH_cfg, &age_mask))
+  if (TALER_Extension_OK != TALER_get_age_mask (TEH_cfg, &age_mask))
   {
     GNUNET_log_config_invalid (GNUNET_ERROR_TYPE_ERROR,
                                TALER_EXTENSION_SECTION_AGE_RESTRICTION,
@@ -761,6 +761,9 @@ load_age_mask (const char*section_name)
 
   if (age_mask.mask == 0)
   {
+    /* Age restriction support is not enabled.  Ignore the AGE_RESTRICTED field
+     * for the particular denomination and simply return the null_mask
+     */
     return null_mask;
   }
 

src/exchange/taler-exchange-httpd_management.h

@@ -135,4 +135,25 @@ TEH_handler_management_post_wire_fees (
   const json_t *root);
 
 
+/**
+ * Handle a POST "/management/extensions" request.
+ *
+ * @param connection the MHD connection to handle
+ * @param root uploaded JSON data
+ * @return MHD result code
+ */
+MHD_RESULT
+TEH_handler_management_post_extensions (
+  struct MHD_Connection *connection,
+  const json_t *root);
+
+
+/**
+ * Initialize extension configuration handling.
+ *
+ * @return #GNUNET_OK on success
+ */
+enum GNUNET_GenericReturnValue
+TEH_extensions_init (void);
+
 #endif

src/exchange/taler-exchange-httpd_management_extensions.c

@@ -0,0 +1,422 @@
+/*
+  This file is part of TALER
+  Copyright (C) 2021 Taler Systems SA
+
+  TALER 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, 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 Affero General Public License for more details.
+
+  You should have received a copy of the GNU Affero General Public License along with
+  TALER; see the file COPYING.  If not, see <http://www.gnu.org/licenses/>
+*/
+/**
+ * @file taler-exchange-httpd_management_extensions.c
+ * @brief Handle request to POST /management/extensions
+ * @author Özgür Kesim
+ */
+#include "platform.h"
+#include <gnunet/gnunet_util_lib.h>
+#include <gnunet/gnunet_json_lib.h>
+#include <jansson.h>
+#include <microhttpd.h>
+#include <pthread.h>
+#include "taler_json_lib.h"
+#include "taler_mhd_lib.h"
+#include "taler_signatures.h"
+#include "taler-exchange-httpd_management.h"
+#include "taler-exchange-httpd_responses.h"
+
+
+#if 0
+/**
+ * Function implementing database transaction to add offline signing keys.
+ * Runs the transaction logic; IF it returns a non-error code, the transaction
+ * logic MUST NOT queue a MHD response.  IF it returns an hard error, the
+ * transaction logic MUST queue a MHD response and set @a mhd_ret.  IF it
+ * returns the soft error code, the function MAY be called again to retry and
+ * MUST not queue a MHD response.
+ *
+ * @param cls closure with a `struct AddKeysContext`
+ * @param connection MHD request which triggered the transaction
+ * @param[out] mhd_ret set to MHD response status for @a connection,
+ *             if transaction failed (!)
+ * @return transaction status
+ */
+static enum GNUNET_DB_QueryStatus
+add_keys (void *cls,
+          struct MHD_Connection *connection,
+          MHD_RESULT *mhd_ret)
+{
+  struct AddKeysContext *akc = cls;
+
+  /* activate all denomination keys */
+  for (unsigned int i = 0; i<akc->nd_sigs; i++)
+  {
+    struct DenomSig *d = &akc->d_sigs[i];
+    enum GNUNET_DB_QueryStatus qs;
+    bool is_active = false;
+    struct TALER_EXCHANGEDB_DenominationKeyMetaData meta;
+    struct TALER_DenominationPublicKey denom_pub;
+
+    /* For idempotency, check if the key is already active */
+    memset (&denom_pub,
+            0,
+            sizeof (denom_pub));
+    qs = TEH_plugin->lookup_denomination_key (
+      TEH_plugin->cls,
+      &d->h_denom_pub,
+      &meta);
+    if (qs < 0)
+    {
+      if (GNUNET_DB_STATUS_SOFT_ERROR == qs)
+        return qs;
+      GNUNET_break (0);
+      *mhd_ret = TALER_MHD_reply_with_error (connection,
+                                             MHD_HTTP_INTERNAL_SERVER_ERROR,
+                                             TALER_EC_GENERIC_DB_FETCH_FAILED,
+                                             "lookup denomination key");
+      return qs;
+    }
+    if (0 == qs)
+    {
+      enum GNUNET_GenericReturnValue rv;
+
+      rv = TEH_keys_load_fees (&d->h_denom_pub,
+                               &denom_pub,
+                               &meta);
+      switch (rv)
+      {
+      case GNUNET_SYSERR:
+        *mhd_ret = TALER_MHD_reply_with_error (
+          connection,
+          MHD_HTTP_INTERNAL_SERVER_ERROR,
+          TALER_EC_EXCHANGE_GENERIC_BAD_CONFIGURATION,
+          GNUNET_h2s (&d->h_denom_pub.hash));
+        return GNUNET_DB_STATUS_HARD_ERROR;
+      case GNUNET_NO:
+        *mhd_ret = TALER_MHD_reply_with_error (
+          connection,
+          MHD_HTTP_NOT_FOUND,
+          TALER_EC_EXCHANGE_GENERIC_DENOMINATION_KEY_UNKNOWN,
+          GNUNET_h2s (&d->h_denom_pub.hash));
+        return GNUNET_DB_STATUS_HARD_ERROR;
+      case GNUNET_OK:
+        break;
+      }
+    }
+    else
+    {
+      is_active = true;
+    }
+
+    /* check signature is valid */
+    if (GNUNET_OK !=
+        TALER_exchange_offline_denom_validity_verify (
+          &d->h_denom_pub,
+          meta.start,
+          meta.expire_withdraw,
+          meta.expire_deposit,
+          meta.expire_legal,
+          &meta.value,
+          &meta.fee_withdraw,
+          &meta.fee_deposit,
+          &meta.fee_refresh,
+          &meta.fee_refund,
+          &TEH_master_public_key,
+          &d->master_sig))
+    {
+      GNUNET_break_op (0);
+      *mhd_ret = TALER_MHD_reply_with_error (
+        connection,
+        MHD_HTTP_FORBIDDEN,
+        TALER_EC_EXCHANGE_MANAGEMENT_KEYS_DENOMKEY_ADD_SIGNATURE_INVALID,
+        GNUNET_h2s (&d->h_denom_pub.hash));
+      if (! is_active)
+        TALER_denom_pub_free (&denom_pub);
+      return GNUNET_DB_STATUS_HARD_ERROR;
+    }
+    if (is_active)
+    {
+      GNUNET_log (GNUNET_ERROR_TYPE_INFO,
+                  "Denomination key %s already active, skipping\n",
+                  GNUNET_h2s (&d->h_denom_pub.hash));
+      continue; /* skip, already known */
+    }
+    qs = TEH_plugin->add_denomination_key (
+      TEH_plugin->cls,
+      &d->h_denom_pub,
+      &denom_pub,
+      &meta,
+      &d->master_sig);
+    TALER_denom_pub_free (&denom_pub);
+    if (qs < 0)
+    {
+      if (GNUNET_DB_STATUS_SOFT_ERROR == qs)
+        return qs;
+      GNUNET_break (0);
+      *mhd_ret = TALER_MHD_reply_with_error (connection,
+                                             MHD_HTTP_INTERNAL_SERVER_ERROR,
+                                             TALER_EC_GENERIC_DB_STORE_FAILED,
+                                             "activate denomination key");
+      return qs;
+    }
+    GNUNET_log (GNUNET_ERROR_TYPE_INFO,
+                "Added offline signature for denomination `%s'\n",
+                GNUNET_h2s (&d->h_denom_pub.hash));
+    GNUNET_assert (0 != qs);
+  }
+
+  for (unsigned int i = 0; i<akc->ns_sigs; i++)
+  {
+    struct SigningSig *s = &akc->s_sigs[i];
+    enum GNUNET_DB_QueryStatus qs;
+    bool is_active = false;
+    struct TALER_EXCHANGEDB_SignkeyMetaData meta;
+
+    qs = TEH_plugin->lookup_signing_key (
+      TEH_plugin->cls,
+      &s->exchange_pub,
+      &meta);
+    if (qs < 0)
+    {
+      if (GNUNET_DB_STATUS_SOFT_ERROR == qs)
+        return qs;
+      GNUNET_break (0);
+      *mhd_ret = TALER_MHD_reply_with_error (connection,
+                                             MHD_HTTP_INTERNAL_SERVER_ERROR,
+                                             TALER_EC_GENERIC_DB_FETCH_FAILED,
+                                             "lookup signing key");
+      return qs;
+    }
+    if (0 == qs)
+    {
+      if (GNUNET_OK !=
+          TEH_keys_get_timing (&s->exchange_pub,
+                               &meta))
+      {
+        /* For idempotency, check if the key is already active */
+        *mhd_ret = TALER_MHD_reply_with_error (
+          connection,
+          MHD_HTTP_NOT_FOUND,
+          TALER_EC_EXCHANGE_MANAGEMENT_KEYS_SIGNKEY_UNKNOWN,
+          TALER_B2S (&s->exchange_pub));
+        return GNUNET_DB_STATUS_HARD_ERROR;
+      }
+    }
+    else
+    {
+      is_active = true; /* if we pass, it's active! */
+    }
+
+    /* check signature is valid */
+    if (GNUNET_OK !=
+        TALER_exchange_offline_signkey_validity_verify (
+          &s->exchange_pub,
+          meta.start,
+          meta.expire_sign,
+          meta.expire_legal,
+          &TEH_master_public_key,
+          &s->master_sig))
+    {
+      GNUNET_break_op (0);
+      *mhd_ret = TALER_MHD_reply_with_error (
+        connection,
+        MHD_HTTP_FORBIDDEN,
+        TALER_EC_EXCHANGE_MANAGEMENT_KEYS_SIGNKEY_ADD_SIGNATURE_INVALID,
+        TALER_B2S (&s->exchange_pub));
+      return GNUNET_DB_STATUS_HARD_ERROR;
+    }
+    if (is_active)
+    {
+      GNUNET_log (GNUNET_ERROR_TYPE_INFO,
+                  "Signing key %s already active, skipping\n",
+                  TALER_B2S (&s->exchange_pub));
+      continue;   /* skip, already known */
+    }
+    qs = TEH_plugin->activate_signing_key (
+      TEH_plugin->cls,
+      &s->exchange_pub,
+      &meta,
+      &s->master_sig);
+    if (qs < 0)
+    {
+      if (GNUNET_DB_STATUS_SOFT_ERROR == qs)
+        return qs;
+      GNUNET_break (0);
+      *mhd_ret = TALER_MHD_reply_with_error (connection,
+                                             MHD_HTTP_INTERNAL_SERVER_ERROR,
+                                             TALER_EC_GENERIC_DB_STORE_FAILED,
+                                             "activate signing key");
+      return qs;
+    }
+    GNUNET_log (GNUNET_ERROR_TYPE_INFO,
+                "Added offline signature for signing key `%s'\n",
+                TALER_B2S (&s->exchange_pub));
+    GNUNET_assert (0 != qs);
+  }
+  return GNUNET_DB_STATUS_SUCCESS_ONE_RESULT; /* only 'success', so >=0, matters here */
+}
+
+
+#endif
+
+MHD_RESULT
+TEH_handler_management_post_extensions (
+  struct MHD_Connection *connection,
+  const json_t *root)
+{
+#if 0
+  json_t *denom_sigs;
+  json_t *signkey_sigs;
+  struct GNUNET_JSON_Specification spec[] = {
+    GNUNET_JSON_spec_json ("denom_sigs",
+                           &denom_sigs),
+    GNUNET_JSON_spec_json ("signkey_sigs",
+                           &signkey_sigs),
+    GNUNET_JSON_spec_end ()
+  };
+  bool ok;
+  MHD_RESULT ret;
+
+  {
+    enum GNUNET_GenericReturnValue res;
+
+    res = TALER_MHD_parse_json_data (connection,
+                                     root,
+                                     spec);
+    if (GNUNET_SYSERR == res)
+      return MHD_NO; /* hard failure */
+    if (GNUNET_NO == res)
+      return MHD_YES; /* failure */
+  }
+  if (! (json_is_array (denom_sigs) &&
+         json_is_array (signkey_sigs)) )
+  {
+    GNUNET_break_op (0);
+    GNUNET_JSON_parse_free (spec);
+    return TALER_MHD_reply_with_error (
+      connection,
+      MHD_HTTP_BAD_REQUEST,
+      TALER_EC_GENERIC_PARAMETER_MALFORMED,
+      "array expected for denom_sigs and signkey_sigs");
+  }
+  GNUNET_log (GNUNET_ERROR_TYPE_INFO,
+              "Received /management/keys\n");
+  akc.nd_sigs = json_array_size (denom_sigs);
+  akc.d_sigs = GNUNET_new_array (akc.nd_sigs,
+                                 struct DenomSig);
+  ok = true;
+  for (unsigned int i = 0; i<akc.nd_sigs; i++)
+  {
+    struct DenomSig *d = &akc.d_sigs[i];
+    struct GNUNET_JSON_Specification ispec[] = {
+      GNUNET_JSON_spec_fixed_auto ("master_sig",
+                                   &d->master_sig),
+      GNUNET_JSON_spec_fixed_auto ("h_denom_pub",
+                                   &d->h_denom_pub),
+      GNUNET_JSON_spec_end ()
+    };
+    enum GNUNET_GenericReturnValue res;
+
+    res = TALER_MHD_parse_json_data (connection,
+                                     json_array_get (denom_sigs,
+                                                     i),
+                                     ispec);
+    if (GNUNET_SYSERR == res)
+    {
+      ret = MHD_NO; /* hard failure */
+      ok = false;
+      break;
+    }
+    if (GNUNET_NO == res)
+    {
+      ret = MHD_YES;
+      ok = false;
+      break;
+    }
+  }
+  if (! ok)
+  {
+    GNUNET_free (akc.d_sigs);
+    GNUNET_JSON_parse_free (spec);
+    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+                "Failure to handle /management/keys\n");
+    return ret;
+  }
+  akc.ns_sigs = json_array_size (signkey_sigs);
+  akc.s_sigs = GNUNET_new_array (akc.ns_sigs,
+                                 struct SigningSig);
+  for (unsigned int i = 0; i<akc.ns_sigs; i++)
+  {
+    struct SigningSig *s = &akc.s_sigs[i];
+    struct GNUNET_JSON_Specification ispec[] = {
+      GNUNET_JSON_spec_fixed_auto ("master_sig",
+                                   &s->master_sig),
+      GNUNET_JSON_spec_fixed_auto ("exchange_pub",
+                                   &s->exchange_pub),
+      GNUNET_JSON_spec_end ()
+    };
+    enum GNUNET_GenericReturnValue res;
+
+    res = TALER_MHD_parse_json_data (connection,
+                                     json_array_get (signkey_sigs,
+                                                     i),
+                                     ispec);
+    if (GNUNET_SYSERR == res)
+    {
+      ret = MHD_NO; /* hard failure */
+      ok = false;
+      break;
+    }
+    if (GNUNET_NO == res)
+    {
+      ret = MHD_YES;
+      ok = false;
+      break;
+    }
+  }
+  if (! ok)
+  {
+    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+                "Failure to handle /management/keys\n");
+    GNUNET_free (akc.d_sigs);
+    GNUNET_free (akc.s_sigs);
+    GNUNET_JSON_parse_free (spec);
+    return ret;
+  }
+  GNUNET_log (GNUNET_ERROR_TYPE_INFO,
+              "Received %u denomination and %u signing key signatures\n",
+              akc.nd_sigs,
+              akc.ns_sigs);
+  {
+    enum GNUNET_GenericReturnValue res;
+
+    res = TEH_DB_run_transaction (connection,
+                                  "add keys",
+                                  TEH_MT_OTHER,
+                                  &ret,
+                                  &add_keys,
+                                  &akc);
+    GNUNET_free (akc.d_sigs);
+    GNUNET_free (akc.s_sigs);
+    GNUNET_JSON_parse_free (spec);
+    if (GNUNET_SYSERR == res)
+      return ret;
+  }
+  TEH_keys_update_states ();
+#endif
+
+  return TALER_MHD_reply_static (
+    connection,
+    MHD_HTTP_NO_CONTENT,
+    NULL,
+    NULL,
+    0);
+}
+
+
+/* end of taler-exchange-httpd_management_management_post_extensions.c */

src/exchange/taler-exchange-httpd_wire.c

@@ -130,7 +130,7 @@ TEH_wire_init ()
 
 
 void
-TEH_WIRE_done ()
+TEH_wire_done ()
 {
   if (NULL != wire_state)
   {

src/exchange/taler-exchange-httpd_wire.h

@@ -30,7 +30,7 @@
  * Clean up wire subsystem.
  */
 void
-TEH_WIRE_done (void);
+TEH_wire_done (void);
 
 
 /**

src/exchangedb/exchange-0001.sql

@@ -280,6 +280,22 @@ COMMENT ON TABLE signkey_revocations
   IS 'Table storing which online signing keys have been revoked';
 
 
+CREATE TABLE IF NOT EXISTS extensions
+  (extension_id BIGSERIAL UNIQUE
+  ,name VARCHAR NOT NULL UNIQUE
+  ,config BYTEA NOT NULL
+  ,config_sig BYTEA NOT NULL
+  );
+COMMENT ON TABLE extensions
+  IS 'Configurations of the activated extensions';
+COMMENT ON COLUMN extensions.name
+  IS 'Name of the extension';
+COMMENT ON COLUMN extensions.config
+  IS 'Configuration of the extension as JSON-blob';
+COMMENT ON COLUMN extensions.config
+  IS 'Signature of the configuration of an extension, signed with the master key of the exchange';
+
+
 CREATE TABLE IF NOT EXISTS known_coins
   (known_coin_id BIGSERIAL UNIQUE
   ,coin_pub BYTEA NOT NULL PRIMARY KEY CHECK (LENGTH(coin_pub)=32)

src/include/taler_exchange_service.h

@@ -1,18 +1,18 @@
 /*
-  This file is part of TALER
+   This file is part of TALER
-  Copyright (C) 2014-2021 Taler Systems SA
+   Copyright (C) 2014-2021 Taler Systems SA
 
-  TALER is free software; you can redistribute it and/or modify it under the
+   TALER 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
+   terms of the GNU Affero General Public License as published by the Free Software
-  Foundation; either version 3, or (at your option) any later version.
+   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
+   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
+   WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
-  A PARTICULAR PURPOSE.  See the GNU Affero General Public License for more details.
+   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
+   You should have received a copy of the GNU Affero General Public License along with
-  TALER; see the file COPYING.  If not, see <http://www.gnu.org/licenses/>
+   TALER; see the file COPYING.  If not, see <http://www.gnu.org/licenses/>
-*/
+ */
 /**
  * @file include/taler_exchange_service.h
  * @brief C interface of libtalerexchange, a C library to use exchange's HTTP API
@@ -1527,7 +1527,7 @@ typedef void
  *
  * @param exchange the exchange handle; the exchange must be ready to operate
  * @param refresh_data the refresh data as returned from
-          #TALER_EXCHANGE_refresh_prepare())
+ #TALER_EXCHANGE_refresh_prepare())
  * @param melt_cb the callback to call with the result
  * @param melt_cb_cls closure for @a melt_cb
  * @return a handle for this request; NULL if the argument was invalid.
@@ -1593,7 +1593,7 @@ struct TALER_EXCHANGE_RefreshesRevealHandle;
  *
  * @param exchange the exchange handle; the exchange must be ready to operate
  * @param refresh_data the refresh data as returned from
-          #TALER_EXCHANGE_refresh_prepare())
+ #TALER_EXCHANGE_refresh_prepare())
  * @param noreveal_index response from the exchange to the
  *        #TALER_EXCHANGE_melt() invocation
  * @param reveal_cb the callback to call with the final result of the
@@ -2615,6 +2615,62 @@ void
 TALER_EXCHANGE_post_management_keys_cancel (
   struct TALER_EXCHANGE_ManagementPostKeysHandle *ph);
 
+
+/**
+ * Information needed for a POST /management/extensions operation.
+ */
+struct TALER_EXCHANGE_ManagementPostExtensionsData
+{
+  struct TALER_Extension *extensions;
+  struct TALER_MasterSignatureP *extension_sigs;
+  uint32_t num_extensions;
+};
+
+/**
+ * Function called with information about the post extensions operation result.
+ *
+ * @param cls closure
+ * @param hr HTTP response data
+ */
+typedef void
+(*TALER_EXCHANGE_ManagementPostExtensionsCallback) (
+  void *cls,
+  const struct TALER_EXCHANGE_HttpResponse *hr);
+
+/**
+ * @brief Handle for a POST /management/extensions request.
+ */
+struct TALER_EXCHANGE_ManagementPostExtensionsHandle;
+
+
+/**
+ * FIXME-oec: Provide correct explanation of this function.
+ *
+ * @param ctx the context
+ * @param url HTTP base URL for the exchange
+ * @param pkd signature data to POST
+ * @param cb function to call with the exchange's result
+ * @param cb_cls closure for @a cb
+ * @return the request handle; NULL upon error
+ */
+struct TALER_EXCHANGE_ManagementPostExtensionsHandle *
+TALER_EXCHANGE_management_post_extensions (
+  struct GNUNET_CURL_Context *ctx,
+  const char *url,
+  const struct TALER_EXCHANGE_ManagementPostExtensionsData *pkd,
+  TALER_EXCHANGE_ManagementPostExtensionsCallback cb,
+  void *cb_cls);
+
+/**
+ * Cancel #TALER_EXCHANGE_post_management_extensions() operation.
+ *
+ * @param ph handle of the operation to cancel
+ */
+void
+TALER_EXCHANGE_post_management_extensions_cancel (
+  struct TALER_EXCHANGE_ManagementPostExtensionsHandle *ph);
+
+
 /**
  * Function called with information about the post revocation operation result.
  *

src/include/taler_exchangedb_plugin.h

@@ -4038,6 +4038,9 @@ struct TALER_EXCHANGEDB_Plugin
   enum GNUNET_DB_QueryStatus
   (*delete_revolving_shards)(void *cls);
 
+  /**
+   * TODO-oec: add function for adding extension config
+   */
 
 };
 

src/include/taler_extensions.h

@@ -26,21 +26,70 @@
 
 #define TALER_EXTENSION_SECTION_PREFIX "exchange-extension-"
 
-enum TALER_EXTENSION_ReturnValue
+enum TALER_Extension_ReturnValue
 {
-  TALER_EXTENSION_OK = 0,
+  TALER_Extension_OK = 0,
-  TALER_EXTENSION_ERROR_PARSING = 1,
+  TALER_Extension_ERROR_PARSING = 1,
-  TALER_EXTENSION_ERROR_INVALID = 2,
+  TALER_Extension_ERROR_INVALID = 2,
-  TALER_EXTENSION_ERROR_SYS = 3
+  TALER_Extension_ERROR_SYS = 3
+};
+
+enum TALER_Extension_Type
+{
+  TALER_Extension_Peer2Peer = 0,
+  TALER_Extension_AgeRestriction = 1,
+  TALER_Extension_Max = 2
+};
+
+struct TALER_Extension
+{
+  enum TALER_Extension_Type type;
+  char *name;
+  bool critical;
+  void *config;
+  size_t config_size;
+};
+
+struct TALER_Peer2Peer_Config
+{
+  // FIXME
+};
+
+/**
+ * TEH_extensions is the global manifest with the list supported extensions,
+ * sorted by TALER_Extension_Type.
+ *
+ * TODO: Mutex?
+ *
+ **/
+struct TALER_Extension TEH_extensions[TALER_Extension_Max] = {
+  [TALER_Extension_Peer2Peer] = {
+    .type = TALER_Extension_Peer2Peer,
+    .name = "peer2peer",
+    .critical = false,
+    .config_size = sizeof(struct TALER_Peer2Peer_Config),
+  },
+  [TALER_Extension_AgeRestriction] = {
+    .type = TALER_Extension_AgeRestriction,
+    .name = "age_restriction",
+    .critical = false,
+    .config_size = sizeof(struct TALER_AgeMask),
+  },
 };
 
 
 /*
- * TALER Age Restriction Extensions
+ * TALER Peer2Peer Extension
+ * FIXME
+ */
+
+
+/*
+ * TALER Age Restriction Extension
  */
 
 #define TALER_EXTENSION_SECTION_AGE_RESTRICTION (TALER_EXTENSION_SECTION_PREFIX  \
-                                                 "agerestriction")
+                                                 "age_restriction")
 
 /**
  * The default age mask represents the age groups
@@ -55,7 +104,7 @@ enum TALER_EXTENSION_ReturnValue
  * @param[out] mask Mask representation for age restriction.
  * @return Error, if age groups were invalid, OK otherwise.
  */
-enum TALER_EXTENSION_ReturnValue
+enum TALER_Extension_ReturnValue
 TALER_parse_age_group_string (char *groups,
                               struct TALER_AgeMask *mask);
 
@@ -66,8 +115,7 @@ TALER_parse_age_group_string (char *groups,
  * @return Error if extension for age restriction was set but age groups were
  *         invalid, OK otherwise.
  */
-enum TALER_EXTENSION_ReturnValue
+enum TALER_Extension_ReturnValue
 TALER_get_age_mask (const struct GNUNET_CONFIGURATION_Handle *cfg,
                     struct TALER_AgeMask *mask);
-
 #endif

src/lib/Makefile.am

@@ -35,6 +35,7 @@ libtalerexchange_la_SOURCES = \
   exchange_api_management_auditor_enable.c \
   exchange_api_management_get_keys.c \
   exchange_api_management_post_keys.c \
+  exchange_api_management_post_extensions.c \
   exchange_api_management_revoke_denomination_key.c \
   exchange_api_management_revoke_signing_key.c \
   exchange_api_management_set_wire_fee.c \

src/lib/exchange_api_management_post_extensions.c

@@ -0,0 +1,251 @@
+/*
+  This file is part of TALER
+  Copyright (C) 2015-2021 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 lib/exchange_api_management_post_extensions.c
+ * @brief functions to handle the settings for extensions (p2p and age restriction)
+ * @author Özgür Kesim
+ */
+#include "platform.h"
+#include "taler_json_lib.h"
+#include <gnunet/gnunet_curl_lib.h>
+#include "taler_extensions.h"
+#include "taler_exchange_service.h"
+#include "taler_signatures.h"
+#include "taler_curl_lib.h"
+#include "taler_json_lib.h"
+
+
+/**
+ * @brief Handle for a POST /management/extensions request.
+ */
+struct TALER_EXCHANGE_ManagementPostExtensionsHandle
+{
+
+  /**
+   * The url for this request.
+   */
+  char *url;
+
+  /**
+   * Minor context that holds body and headers.
+   */
+  struct TALER_CURL_PostContext post_ctx;
+
+  /**
+   * Handle for the request.
+   */
+  struct GNUNET_CURL_Job *job;
+
+  /**
+   * Function to call with the result.
+   */
+  TALER_EXCHANGE_ManagementPostExtensionsCallback cb;
+
+  /**
+   * Closure for @a cb.
+   */
+  void *cb_cls;
+
+  /**
+   * Reference to the execution context.
+   */
+  struct GNUNET_CURL_Context *ctx;
+};
+
+
+/**
+ * Function called when we're done processing the
+ * HTTP POST /management/extensions request.
+ *
+ * @param cls the `struct TALER_EXCHANGE_ManagementPostExtensionsHandle *`
+ * @param response_code HTTP response code, 0 on error
+ * @param response response body, NULL if not in JSON
+ */
+static void
+handle_post_extensions_finished (void *cls,
+                                 long response_code,
+                                 const void *response)
+{
+  struct TALER_EXCHANGE_ManagementPostExtensionsHandle *ph = cls;
+  const json_t *json = response;
+  struct TALER_EXCHANGE_HttpResponse hr = {
+    .http_status = (unsigned int) response_code,
+    .reply = json
+  };
+
+  ph->job = NULL;
+  switch (response_code)
+  {
+  case MHD_HTTP_NO_CONTENT:
+    break;
+  case MHD_HTTP_FORBIDDEN:
+    hr.ec = TALER_JSON_get_error_code (json);
+    hr.hint = TALER_JSON_get_error_hint (json);
+    break;
+  case MHD_HTTP_NOT_FOUND:
+    hr.ec = TALER_JSON_get_error_code (json);
+    hr.hint = TALER_JSON_get_error_hint (json);
+    break;
+  default:
+    /* unexpected response code */
+    GNUNET_break_op (0);
+    hr.ec = TALER_JSON_get_error_code (json);
+    hr.hint = TALER_JSON_get_error_hint (json);
+    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+                "Unexpected response code %u/%d for exchange management post extensions\n",
+                (unsigned int) response_code,
+                (int) hr.ec);
+    break;
+  }
+  if (NULL != ph->cb)
+  {
+    ph->cb (ph->cb_cls,
+            &hr);
+    ph->cb = NULL;
+  }
+  TALER_EXCHANGE_post_management_extensions_cancel (ph);
+}
+
+
+struct TALER_EXCHANGE_ManagementPostExtensionsHandle *
+TALER_EXCHANGE_management_post_extensions (
+  struct GNUNET_CURL_Context *ctx,
+  const char *url,
+  const struct TALER_EXCHANGE_ManagementPostExtensionsData *pkd,
+  TALER_EXCHANGE_ManagementPostKeysCallback cb,
+  void *cb_cls)
+{
+  struct TALER_EXCHANGE_ManagementPostExtensionsHandle *ph;
+  //  FIXME-oec: TODO!
+  CURL *eh = NULL;
+  json_t *body;
+  json_t *extensions = NULL;
+  json_t *extension_sigs = NULL;
+
+  ph = GNUNET_new (struct TALER_EXCHANGE_ManagementPostExtensionsHandle);
+  ph->cb = cb;
+  ph->cb_cls = cb_cls;
+  ph->ctx = ctx;
+  ph->url = TALER_url_join (url,
+                            "management/extensions",
+                            NULL);
+  if (NULL == ph->url)
+  {
+    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+                "Could not construct request URL.\n");
+    GNUNET_free (ph);
+    return NULL;
+  }
+  extensions = json_array ();
+  GNUNET_assert (NULL != extensions);
+  for (unsigned int i = 0; i<pkd->num_extensions; i++)
+  {
+    json_t *config;
+    const struct TALER_AgeMask *mask;
+    const struct TALER_Extension *ext
+      = &pkd->extensions[i];
+
+    switch (ext->type)
+    {
+    // TODO: case TALER_Extension_Peer2Peer
+    case TALER_Extension_AgeRestriction:
+      mask = (struct TALER_AgeMask *) (&ext->config);
+      config = GNUNET_JSON_PACK (GNUNET_JSON_pack_data_auto ("mask",
+                                                             &mask->mask));
+      GNUNET_assert (NULL != config);
+      break;
+    default:
+      GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+                  "Extension not supported.\n");
+    }
+
+    GNUNET_assert (0 ==
+                   json_array_append_new (
+                     extensions,
+                     GNUNET_JSON_PACK (
+                       GNUNET_JSON_pack_data_auto ("extension",
+                                                   &ext->name),
+                       GNUNET_JSON_pack_data_auto ("config",
+                                                   config)
+                       )));
+  }
+  extension_sigs = json_array ();
+  GNUNET_assert (NULL != extension_sigs);
+  for (unsigned int i = 0; i<pkd->num_extensions; i++)
+  {
+    const struct TALER_MasterSignatureP *sks
+      = &pkd->extension_sigs[i];
+
+    GNUNET_assert (0 ==
+                   json_array_append_new (
+                     extension_sigs,
+                     GNUNET_JSON_PACK (
+                       GNUNET_JSON_pack_data_auto ("extension_sig",
+                                                   &sks->eddsa_signature))));
+  }
+  body = GNUNET_JSON_PACK (
+    GNUNET_JSON_pack_array_steal ("extensions",
+                                  extensions),
+    GNUNET_JSON_pack_array_steal ("extension_sigs",
+                                  extension_sigs));
+  eh = curl_easy_init ();
+  GNUNET_assert (NULL != eh);
+  if (GNUNET_OK !=
+      TALER_curl_easy_post (&ph->post_ctx,
+                            eh,
+                            body))
+  {
+    GNUNET_break (0);
+    json_decref (body);
+    GNUNET_free (ph->url);
+    GNUNET_free (eh);
+    return NULL;
+  }
+  json_decref (body);
+  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+              "Requesting URL '%s'\n",
+              ph->url);
+  GNUNET_assert (CURLE_OK == curl_easy_setopt (eh,
+                                               CURLOPT_URL,
+                                               ph->url));
+  ph->job = GNUNET_CURL_job_add2 (ctx,
+                                  eh,
+                                  ph->post_ctx.headers,
+                                  &handle_post_extensions_finished,
+                                  ph);
+  if (NULL == ph->job)
+  {
+    TALER_EXCHANGE_post_management_extensions_cancel (ph);
+    return NULL;
+  }
+  return ph;
+}
+
+
+void
+TALER_EXCHANGE_post_management_extensions_cancel (
+  struct TALER_EXCHANGE_ManagementPostExtensionsHandle *ph)
+{
+  if (NULL != ph->job)
+  {
+    GNUNET_CURL_job_cancel (ph->job);
+    ph->job = NULL;
+  }
+  TALER_curl_easy_post_finished (&ph->post_ctx);
+  GNUNET_free (ph->url);
+  GNUNET_free (ph);
+}

src/util/extension_age_restriction.c

@@ -31,12 +31,12 @@
  * @return Error if extension for age restriction was set, but age groups were
  *         invalid, OK otherwise.
  */
-enum TALER_EXTENSION_ReturnValue
+enum TALER_Extension_ReturnValue
 TALER_get_age_mask (const struct GNUNET_CONFIGURATION_Handle *cfg,
                     struct TALER_AgeMask *mask)
 {
   char *groups;
-  enum TALER_EXTENSION_ReturnValue ret = TALER_EXTENSION_ERROR_SYS;
+  enum TALER_Extension_ReturnValue ret = TALER_Extension_ERROR_SYS;
 
   if ((GNUNET_NO == GNUNET_CONFIGURATION_have_value (cfg,
                                                      TALER_EXTENSION_SECTION_AGE_RESTRICTION,
@@ -47,7 +47,7 @@ TALER_get_age_mask (const struct GNUNET_CONFIGURATION_Handle *cfg,
   {
     /* Age restriction is not enabled */
     mask->mask = 0;
-    return TALER_EXTENSION_OK;
+    return TALER_Extension_OK;
   }
 
   /* Age restriction is enabled, extract age groups */
@@ -57,13 +57,13 @@ TALER_get_age_mask (const struct GNUNET_CONFIGURATION_Handle *cfg,
                                                           &groups))
   {
     /* FIXME: log error? */
-    return TALER_EXTENSION_ERROR_SYS;
+    return TALER_Extension_ERROR_SYS;
   }
   if (groups == NULL)
   {
     /* No groups defined in config, return default_age_mask */
     mask->mask = TALER_EXTENSION_DEFAULT_AGE_MASK;
-    return TALER_EXTENSION_OK;
+    return TALER_Extension_OK;
   }
 
   ret = TALER_parse_age_group_string (groups, mask);
@@ -80,11 +80,11 @@ TALER_get_age_mask (const struct GNUNET_CONFIGURATION_Handle *cfg,
  * @param[out] mask Bit representation of the age groups.
  * @return Error if string was invalid, OK otherwise.
  */
-enum TALER_EXTENSION_ReturnValue
+enum TALER_Extension_ReturnValue
 TALER_parse_age_group_string (char *groups,
                               struct TALER_AgeMask *mask)
 {
-  enum TALER_EXTENSION_ReturnValue ret = TALER_EXTENSION_ERROR_SYS;
+  enum TALER_Extension_ReturnValue ret = TALER_Extension_ERROR_SYS;
   char *pos;
   unsigned int prev = 0;
   unsigned int val;
@@ -105,14 +105,14 @@ TALER_parse_age_group_string (char *groups,
     {
       /* Invalid input */
       mask->mask = 0;
-      ret = TALER_EXTENSION_ERROR_PARSING;
+      ret = TALER_Extension_ERROR_PARSING;
       break;
     }
     else if ((0 >= val) || (32 <= val) || (prev >= val))
     {
       /* Invalid value */
       mask->mask = 0;
-      ret = TALER_EXTENSION_ERROR_INVALID;
+      ret = TALER_Extension_ERROR_INVALID;
       break;
     }
 
@@ -123,7 +123,7 @@ TALER_parse_age_group_string (char *groups,
     {
       /* We reached the end. Mark zeroth age-group and exit. */
       mask->mask |= 1;
-      ret = TALER_EXTENSION_OK;
+      ret = TALER_Extension_OK;
       break;
     }
 

src/util/secmod_common.c

@@ -232,8 +232,8 @@ TES_read_work (void *cls,
   struct TES_Client *client = cls;
   char *buf = client->iobuf;
   size_t off = 0;
-  uint16_t msize;
+  uint16_t msize = 0;
-  const struct GNUNET_MessageHeader *hdr;
+  const struct GNUNET_MessageHeader *hdr = NULL;
   enum GNUNET_GenericReturnValue ret;
 
   do