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authorChristian Grothoff <christian@grothoff.org>2020-12-09 12:31:10 +0100
committerChristian Grothoff <christian@grothoff.org>2020-12-09 12:31:10 +0100
commitfa1914b26781a9409a35fd6f8bfb54aae09fdd79 (patch)
tree626be333f8fb26f7a0d58fe334fc7cd41952af08 /src/exchange
parent9911b327ac299ec7eeae81b98cb520f4153071f2 (diff)
downloadexchange-fa1914b26781a9409a35fd6f8bfb54aae09fdd79.tar.gz
exchange-fa1914b26781a9409a35fd6f8bfb54aae09fdd79.tar.bz2
exchange-fa1914b26781a9409a35fd6f8bfb54aae09fdd79.zip
work on new logic to generate /wire response
Diffstat (limited to 'src/exchange')
-rw-r--r--src/exchange/taler-exchange-httpd_wire2.c315
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 00000000..b2f8a2a1
--- /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 */