diff options
Diffstat (limited to 'src/exchange')
| -rw-r--r-- | src/exchange/taler-exchange-httpd_wire2.c | 315 |
1 files changed, 315 insertions, 0 deletions
diff --git a/src/exchange/taler-exchange-httpd_wire2.c b/src/exchange/taler-exchange-httpd_wire2.c new file mode 100644 index 000000000..b2f8a2a1f --- /dev/null +++ b/src/exchange/taler-exchange-httpd_wire2.c @@ -0,0 +1,315 @@ +/* + This file is part of TALER + Copyright (C) 2015-2020 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_wire.c + * @brief Handle /wire requests + * @author Christian Grothoff + */ +#include "platform.h" +#include <gnunet/gnunet_json_lib.h> +#include "taler-exchange-httpd_keystate.h" +#include "taler-exchange-httpd_responses.h" +#include "taler-exchange-httpd_wire.h" +#include "taler_json_lib.h" +#include "taler_mhd_lib.h" +#include <jansson.h> + + +/** + * Thread-local. Contains a pointer to `struct WireStateHandle` or NULL. + * Stores the per-thread latest generation of our wire response. + */ +static pthread_key_t wire_state; + +/** + * Counter incremented whenever we have a reason to re-build the #wire_state + * because something external changed (in another thread). The counter is + * manipulated using an atomic update, and thus to ensure that threads notice + * when it changes, the variable MUST be volatile. See #get_wire_state() + * and #TEH_wire_update_state() for uses of this variable. + */ +static volatile uint64_t wire_generation; + + +/** + * State we keep per thread to cache the /wire response. + */ +struct WireStateHandle +{ + /** + * Cached JSON for /wire response. + */ + json_t *wire_reply; + + /** + * For which (global) wire_generation was this data structure created? + * Used to check when we are outdated and need to be re-generated. + */ + uint64_t wire_generation; + +}; + + +/** + * Free memory assciated with @a wsh + * + * @param[in] wsh wire state to destroy + */ +static void +destroy_wire_state (struct WireStateHandle *wsh) +{ + json_decref (wsh->wire_reply); + GNUNET_free (wsh); +} + + +/** + * Add information about a wire account to @a cls. + * + * @param cls a `json_t *` object to expand with wire account details + * @param payto_uri the exchange bank account URI to add + * @param master_sig master key signature affirming that this is a bank + * account of the exchange (of purpose #TALER_SIGNATURE_MASTER_WIRE_DETAILS) + */ +static void +add_wire_account (void *cls, + const char *payto_uri, + const struct TALER_MasterSignatureP *master_sig) +{ + json_t *a = cls; + + if (0 != + json_array_append_new ( + a, + json_pack ("{s:s, s:o}", + "url", /* "payto_uri" would be better, but this is the name in the spec */ + payto_uri, + "sig", + GNUNET_JSON_from_data_auto (master_sig)))) + { + GNUNET_break (0); /* out of memory!? */ + return; + } +} + + +/** + * Add information about a wire account to @a cls. + * + * @param cls a `json_t *` array to expand with wire account details + * @param wire_fee the wire fee we charge + * @param closing_fee the closing fee we charge + * @param start_date from when are these fees valid (start date) + * @param end_date until when are these fees valid (end date, exclusive) + * @param master_sig master key signature affirming that this is the corrrect + * fee (of purpose #TALER_SIGNATURE_MASTER_WIRE_FEES) + */ +static void +add_wire_fee (void *cls, + const struct TALER_Amount *wire_fee, + const struct TALER_Amount *closing_fee, + struct GNUNET_TIME_Absolute start_date, + struct GNUNET_TIME_Absolute end_date, + const struct TALER_MasterSignatureP *master_sig) +{ + json_t *a = cls; + + if (0 != + json_array_append_new ( + a, + json_pack ("{s:o, s:o, s:o, s:o, s:o}", + "wire_fee", + TALER_JSON_from_amount (wire_fee), + "closing_fee", + TALER_JSON_from_amount (closing_fee), + "start_date", + GNUNET_JSON_from_time_abs (start_date), + "end_date", + GNUNET_JSON_from_time_abs (end_date), + "sig", + GNUNET_JSON_from_data_auto (master_sig)))) + { + GNUNET_break (0); /* out of memory!? */ + return; + } +} + + +/** + * Create the /wire response from our database state. + * + * @return NULL on error + */ +static struct WireStateHandle * +build_wire_state (void) +{ + json_t *wire_accounts_array; + json_t *wire_fee_object; + json_t *wire_reply; + uint64_t wg = wire_generation; /* must be obtained FIRST */ + enum GNUNET_DB_QueryStatus qs; + + wire_accounts_array = json_array (); + GNUNET_assert (NULL != wire_accounts_array); + qs = TEH_plugin->get_wire_accounts (TEH_plugin->cls, + &add_wire_account, + wire_accounts_array); + if (0 > qs) + { + GNUNET_break (0); + json_decref (wire_accounts_array); + return NULL; + } + wire_fee_object = json_object (); + GNUNET_assert (NULL != wire_fee_object); + { + json_t *account; + size_t index; + + json_array_foreach (wire_accounts_array, index, account) { + char *wire_method; + const char *payto_uri = json_string_value (json_object_get (account, + "url")); + GNUNET_assert (NULL != payto_uri); + wire_method = TALER_payto_get_method (payto_uri); + if (NULL == json_object_get (wire_fee_object, + wire_method)) + { + json_t *a = json_array (); + + GNUNET_assert (NULL != a); + qs = TEH_plugin->get_wire_fees (TEH_plugin->cls, + wire_method, + &add_wire_fee, + a); + if (0 > qs) + { + GNUNET_break (0); + json_decref (a); + json_decref (wire_fee_object); + json_decref (wire_accounts_array); + return NULL; + } + GNUNET_assert (0 == + json_object_set_new (wire_fee_object, + wire_method, + a)); + } + GNUNET_free (wire_method); + + } + } + wire_reply = json_pack ( + "{s:O, s:O, s:o}", + "accounts", wire_accounts_array, + "fees", wire_fee_object, + "master_public_key", + GNUNET_JSON_from_data_auto (&TEH_master_public_key)); + GNUNET_assert (NULL != wire_reply); + { + struct WireStateHandle *wsh; + + wsh = GNUNET_new (struct WireStateHandle); + wsh->wire_reply = wire_reply; + wsh->wire_generation = wg; + return wsh; + } +} + + +/** + * Something changed in the database. Rebuild the wire replies. This function + * should be called if the exchange learns about a new signature from our + * master key. + * + * (We do not do so immediately, but merely signal to all threads that they + * need to rebuild their wire state upon the next call to + * #wire_get_state()). + */ +void +TEH_wire_update_state () +{ + __sync_fetch_and_add (&key_generation, + 1); +} + + +/** + * Return the current key state for this thread. Possibly + * re-builds the key state if we have reason to believe + * that something changed. + * + * @return NULL on error + */ +struct WireStateHandle * +get_wire_state (void) +{ + struct WireStateHandle *old_wsh; + struct WireStateHandle *wsh; + + old_wsh = pthread_getspecific (wire_state); + if ( (NULL == old_wsh) || + (old_wsh->key_generation < key_generation) ) + { + wsh = build_wire_state (); + if (NULL == wsh) + return NULL; + if (0 != pthread_setspecific (wire_state, + wsh)) + { + GNUNET_break (0); + destroy_wire_state (wsh); + return NULL; + } + if (NULL != old_wsh) + destroy_key_state (old_wsh, + false); + return wsh; + } + return old_wsh; +} + + +/** + * Handle a "/wire" request. + * + * @param rh context of the handler + * @param connection the MHD connection to handle + * @param args array of additional options (must be empty for this function) + * @return MHD result code + */ +MHD_RESULT +TEH_handler_wire (const struct TEH_RequestHandler *rh, + struct MHD_Connection *connection, + const char *const args[]) +{ + struct WireStateHandle *wsh; + + (void) rh; + (void) args; + wsh = get_wire_state (); + if (NULL == wsh) + TALER_MHD_reply_error (connection, + MHD_HTTP_INTERNAL_SERVER_ERROR, + TALER_EC_WTF, + NULL); + return TALER_MHD_reply_json (connection, + json_incref (wsh->wire_reply), + MHD_HTTP_OK); +} + + +/* end of taler-exchange-httpd_wire.c */ |