Changing configuration structure to enable multiple accounts.

This change enables using multiple wire plugins at the same time.
Also, we now distinguish between the wire plugin (i.e. EBICS or
taler_bank) and the wire method (i.e. SEPA or x-taler-bank) that
the wire plugin is implementing.  The "taler-bank" wire method
was renamed from "test" to "x-taler-bank".

This also changes the format of the /wire response of the exchange,
as we now need to return multiple accounts.  Note that wire fees
are specified per wire method, not per wire account.

taler-exchange-keyup now automatically signs all of the /wire
responses in the location specified by the configuration.

Account identification in wire plugins was changed to use
payto://-URLs instead of method-specific JSON fields.  Signing
and validation of /wire responses was moved from each wire
plugin to a generic validation method in libtalerutil (crypto)
or libtalerjson (for JSON-formatted inputs).
Convenience methods were added to generate JSON for wire accounts
(salting, signing).

Various section and option names were adjusted to streamline the
configuration and make it more consistent overall.  Documentation
was updated as well.

1 files changed, 171 insertions, 148 deletions

diff --git a/src/exchange/taler-exchange-aggregator.c b/src/exchange/taler-exchange-aggregator.c
index 49cbb2b93..fa76cfb03 100644
--- a/src/exchange/taler-exchange-aggregator.c
+++ b/src/exchange/taler-exchange-aggregator.c
@@ -1,6 +1,6 @@
 /*
   This file is part of TALER
-  Copyright (C) 2016, 2017 GNUnet e.V.
+  Copyright (C) 2016-2018 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
@@ -30,19 +30,19 @@
 
 
 /**
- * Information we keep for each loaded wire plugin.
+ * Information we keep for each supported account.
  */
-struct WirePlugin
+struct WireAccount
 {
   /**
-   * Plugins are kept in a DLL.
+   * Accounts are kept in a DLL.
    */
-  struct WirePlugin *next;
+  struct WireAccount *next;
 
   /**
    * Plugins are kept in a DLL.
    */
-  struct WirePlugin *prev;
+  struct WireAccount *prev;
 
   /**
    * Handle to the plugin.
@@ -50,14 +50,14 @@ struct WirePlugin
   struct TALER_WIRE_Plugin *wire_plugin;
 
   /**
-   * Name of the plugin.
+   * Wire transfer fee structure.
    */
-  char *type;
+  struct TALER_EXCHANGEDB_AggregateFees *af;
 
   /**
-   * Wire transfer fee structure.
+   * Name of the section that configures this account.
    */
-  struct TALER_EXCHANGEDB_AggregateFees *af;
+  char *section_name;
 
 };
 
@@ -82,7 +82,7 @@ struct WirePrepareData
   /**
    * Wire plugin used for this preparation.
    */
-  struct WirePlugin *wp;
+  struct WireAccount *wa;
 
   /**
    * Row ID of the transfer.
@@ -149,9 +149,9 @@ struct AggregationUnit
   json_t *wire;
 
   /**
-   * Wire plugin to be used for the preparation.
+   * Wire account to be used for the preparation.
    */
-  struct WirePlugin *wp;
+  struct WireAccount *wa;
 
   /**
    * Database session for all of our transactions.
@@ -200,12 +200,12 @@ struct CloseTransferContext
   /**
    * Wire transfer method.
    */
-  char *type;
+  char *method;
 
   /**
-   * Wire plugin used for closing the reserve.
+   * Wire account used for closing the reserve.
    */
-  struct WirePlugin *wp;
+  struct WireAccount *wa;
 };
 
 
@@ -238,12 +238,12 @@ static struct TALER_EXCHANGEDB_Plugin *db_plugin;
 /**
  * Head of list of loaded wire plugins.
  */
-static struct WirePlugin *wp_head;
+static struct WireAccount *wa_head;
 
 /**
  * Tail of list of loaded wire plugins.
  */
-static struct WirePlugin *wp_tail;
+static struct WireAccount *wa_tail;
 
 /**
  * Next task to run, if any.
@@ -290,49 +290,22 @@ static int reserves_idle;
 static unsigned int aggregation_limit = TALER_EXCHANGEDB_MATCHING_DEPOSITS_LIMIT;
 
 
-/**
- * Extract wire plugin type from @a wire address
- *
- * @param wire a wire address
- * @return NULL if @a wire is ill-formed
- */
-const char *
-extract_type (const json_t *wire)
-{
-  const char *type;
-  json_t *t;
-
-  t = json_object_get (wire, "type");
-  if (NULL == t)
-  {
-    GNUNET_break (0);
-    return NULL;
-  }
-  type = json_string_value (t);
-  if (NULL == type)
-  {
-    GNUNET_break (0);
-    return NULL;
-  }
-  return type;
-}
-
 
 /**
  * Advance the "af" pointer in @a wp to point to the
  * currently valid record.
  *
- * @param wp wire transfer fee data structure to update
+ * @param wa wire transfer fee data structure to update
  * @param now timestamp to update fees to
  */
 static void
-advance_fees (struct WirePlugin *wp,
+advance_fees (struct WireAccount *wa,
               struct GNUNET_TIME_Absolute now)
 {
   struct TALER_EXCHANGEDB_AggregateFees *af;
 
   /* First, try to see if we have current fee information in memory */
-  af = wp->af;
+  af = wa->af;
   while ( (NULL != af) &&
           (af->end_date.abs_value_us < now.abs_value_us) )
   {
@@ -341,7 +314,7 @@ advance_fees (struct WirePlugin *wp,
     GNUNET_free (af);
     af = n;
   }
-  wp->af = af;
+  wa->af = af;
 }
 
 
@@ -354,28 +327,28 @@ advance_fees (struct WirePlugin *wp,
  * @return transaction status
  */
 static enum GNUNET_DB_QueryStatus
-update_fees (struct WirePlugin *wp,
+update_fees (struct WireAccount *wa,
              struct GNUNET_TIME_Absolute now,
              struct TALER_EXCHANGEDB_Session *session)
 {
   enum GNUNET_DB_QueryStatus qs;
 
-  advance_fees (wp,
+  advance_fees (wa,
                 now);
-  if (NULL != wp->af)
+  if (NULL != wa->af)
     return GNUNET_DB_STATUS_SUCCESS_ONE_RESULT;
   /* Let's try to load it from disk... */
-  wp->af = TALER_EXCHANGEDB_fees_read (cfg,
-                                       wp->type);
-  advance_fees (wp,
+  wa->af = TALER_EXCHANGEDB_fees_read (cfg,
+                                       wa->wire_plugin->method);
+  advance_fees (wa,
                 now);
-  for (struct TALER_EXCHANGEDB_AggregateFees *p = wp->af;
+  for (struct TALER_EXCHANGEDB_AggregateFees *p = wa->af;
        NULL != p;
        p = p->next)
   {
     qs = db_plugin->insert_wire_fee (db_plugin->cls,
 				     session,
-				     wp->type,
+				     wa->wire_plugin->method,
 				     p->start_date,
 				     p->end_date,
 				     &p->wire_fee,
@@ -383,53 +356,94 @@ update_fees (struct WirePlugin *wp,
 				     &p->master_sig);
     if (qs < 0)
     {
-      TALER_EXCHANGEDB_fees_free (wp->af);
-      wp->af = NULL;
+      TALER_EXCHANGEDB_fees_free (wa->af);
+      wa->af = NULL;
       return qs;
     }
   }
-  if (NULL != wp->af)
+  if (NULL != wa->af)
     return GNUNET_DB_STATUS_SUCCESS_ONE_RESULT;
   GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
               "Failed to find current wire transfer fees for `%s'\n",
-              wp->type);
+              wa->wire_plugin->method);
   return GNUNET_DB_STATUS_SUCCESS_NO_RESULTS;
 }
 
 
 /**
- * Find the wire plugin for the given wire address.
+ * Find the wire plugin for the given payto:// URL
  *
- * @param type wire plugin type we need a plugin for
+ * @param method wire method we need an account for
  * @return NULL on error
  */
-static struct WirePlugin *
-find_plugin (const char *type)
+static struct WireAccount *
+find_account_by_method (const char *method)
 {
-  struct WirePlugin *wp;
+  for (struct WireAccount *wa = wa_head; NULL != wa; wa = wa->next)
+    if (0 == strcmp (method,
+                     wa->wire_plugin->method))
+      return wa;
+  return NULL;
+}
+
 
-  if (NULL == type)
+/**
+ * Find the wire plugin for the given payto:// URL
+ *
+ * @param url wire address we need an account for
+ * @return NULL on error
+ */
+static struct WireAccount *
+find_account_by_url (const char *url)
+{
+  char *method;
+  struct WireAccount *wa;
+
+  method = TALER_WIRE_payto_get_method (url);
+  if (NULL == method)
+  {
+    fprintf (stderr,
+             "Invalid payto:// URL `%s'\n",
+             url);
     return NULL;
-  for (wp = wp_head; NULL != wp; wp = wp->next)
-    if (0 == strcmp (type,
-                     wp->type))
-      return wp;
-  wp = GNUNET_new (struct WirePlugin);
-  wp->wire_plugin = TALER_WIRE_plugin_load (cfg,
-                                            type);
-  if (NULL == wp->wire_plugin)
+  }
+  wa = find_account_by_method (method);
+  GNUNET_free (method);
+  return wa;
+}
+
+
+/**
+ * Function called with information about a wire account.  Adds the
+ * account to our list (if it is enabled and we can load the plugin).
+ *
+ * @param cls closure, NULL
+ * @param ai account information
+ */
+static void
+add_account_cb (void *cls,
+                const struct TALER_EXCHANGEDB_AccountInfo *ai)
+{
+  struct WireAccount *wa;
+
+  (void) cls;
+  if (GNUNET_YES != ai->debit_enabled)
+    return; /* not enabled for us, skip */
+  wa = GNUNET_new (struct WireAccount);
+  wa->wire_plugin = TALER_WIRE_plugin_load (cfg,
+                                            ai->plugin_name);
+  if (NULL == wa->wire_plugin)
   {
     fprintf (stderr,
              "Failed to load wire plugin for `%s'\n",
-             type);
-    GNUNET_free (wp);
-    return NULL;
+             ai->plugin_name);
+    GNUNET_free (wa);
+    return;
   }
-  wp->type = GNUNET_strdup (type);
-  GNUNET_CONTAINER_DLL_insert (wp_head,
-                               wp_tail,
-                               wp);
-  return wp;
+  wa->section_name = GNUNET_strdup (ai->section_name);
+  GNUNET_CONTAINER_DLL_insert (wa_head,
+                               wa_tail,
+                               wa);
 }
 
 
@@ -471,7 +485,7 @@ shutdown_task (void *cls)
   {
     if (NULL != wpd->eh)
     {
-      wpd->wp->wire_plugin->execute_wire_transfer_cancel (wpd->wp->wire_plugin->cls,
+      wpd->wa->wire_plugin->execute_wire_transfer_cancel (wpd->wa->wire_plugin->cls,
                                                           wpd->eh);
       wpd->eh = NULL;
     }
@@ -484,7 +498,7 @@ shutdown_task (void *cls)
   {
     if (NULL != au->ph)
     {
-      au->wp->wire_plugin->prepare_wire_transfer_cancel (au->wp->wire_plugin->cls,
+      au->wa->wire_plugin->prepare_wire_transfer_cancel (au->wa->wire_plugin->cls,
                                                          au->ph);
       au->ph = NULL;
     }
@@ -494,29 +508,29 @@ shutdown_task (void *cls)
   }
   if (NULL != ctc)
   {
-    ctc->wp->wire_plugin->prepare_wire_transfer_cancel (ctc->wp->wire_plugin->cls,
+    ctc->wa->wire_plugin->prepare_wire_transfer_cancel (ctc->wa->wire_plugin->cls,
                                                         ctc->ph);
     ctc->ph = NULL;
     db_plugin->rollback (db_plugin->cls,
                          ctc->session);
-    GNUNET_free (ctc->type);
+    GNUNET_free (ctc->method);
     GNUNET_free (ctc);
     ctc = NULL;
   }
   TALER_EXCHANGEDB_plugin_unload (db_plugin);
 
   {
-    struct WirePlugin *wp;
+    struct WireAccount *wa;
 
-    while (NULL != (wp = wp_head))
+    while (NULL != (wa = wa_head))
     {
-      GNUNET_CONTAINER_DLL_remove (wp_head,
-                                   wp_tail,
-                                   wp);
-      TALER_WIRE_plugin_unload (wp->wire_plugin);
-      TALER_EXCHANGEDB_fees_free (wp->af);
-      GNUNET_free (wp->type);
-      GNUNET_free (wp);
+      GNUNET_CONTAINER_DLL_remove (wa_head,
+                                   wa_tail,
+                                   wa);
+      TALER_WIRE_plugin_unload (wa->wire_plugin);
+      TALER_EXCHANGEDB_fees_free (wa->af);
+      GNUNET_free (wa->section_name);
+      GNUNET_free (wa);
     }
   }
   GNUNET_CONFIGURATION_destroy (cfg);
@@ -568,7 +582,16 @@ exchange_serve_process_config ()
     TALER_EXCHANGEDB_plugin_unload (db_plugin);
     return GNUNET_SYSERR;
   }
-
+  TALER_EXCHANGEDB_find_accounts (cfg,
+                                  &add_account_cb,
+                                  NULL);
+  if (NULL == wa_head)
+  {
+    fprintf (stderr,
+             "No wire accounts configured for debit!\n");
+    TALER_EXCHANGEDB_plugin_unload (db_plugin);
+    return GNUNET_SYSERR;
+  }
   return GNUNET_OK;
 }
 
@@ -677,16 +700,13 @@ deposit_cb (void *cls,
   }
 
   GNUNET_assert (NULL == au->wire);
-  au->wire = json_incref ((json_t *) wire);
-  if (GNUNET_OK !=
-      TALER_JSON_hash (au->wire,
-                       &au->h_wire))
+  if (NULL == (au->wire = json_incref ((json_t *) wire)))
   {
     GNUNET_break (0);
-    json_decref (au->wire);
-    au->wire = NULL;
     return GNUNET_DB_STATUS_HARD_ERROR;
   }
+  TALER_JSON_wire_signature_hash (wire,
+                                  &au->h_wire);
   GNUNET_CRYPTO_random_block (GNUNET_CRYPTO_QUALITY_NONCE,
                               &au->wtid,
                               sizeof (au->wtid));
@@ -695,15 +715,20 @@ deposit_cb (void *cls,
               TALER_B2S (&au->wtid),
               TALER_amount2s (amount_with_fee),
               (unsigned long long) row_id);
+  {
+    char *url;
 
-  au->wp = find_plugin (extract_type (au->wire));
-  if (NULL == au->wp)
+    url = TALER_JSON_wire_to_payto (au->wire);
+    au->wa = find_account_by_url (url);
+    GNUNET_free (url);
+  }
+  if (NULL == au->wa)
     return GNUNET_DB_STATUS_HARD_ERROR;
 
   /* make sure we have current fees */
   au->execution_time = GNUNET_TIME_absolute_get ();
   (void) GNUNET_TIME_round_abs (&au->execution_time);
-  qs = update_fees (au->wp,
+  qs = update_fees (au->wa,
 		    au->execution_time,
 		    au->session);
   if (qs <= 0)
@@ -713,7 +738,7 @@ deposit_cb (void *cls,
     GNUNET_break (GNUNET_DB_STATUS_SOFT_ERROR == qs);
     return qs;
   }
-  au->wire_fee = au->wp->af->wire_fee;
+  au->wire_fee = au->wa->af->wire_fee;
 
   qs = db_plugin->insert_aggregation_tracking (db_plugin->cls,
 					       au->session,
@@ -942,7 +967,7 @@ prepare_close_cb (void *cls,
     db_plugin->rollback (db_plugin->cls,
                          ctc->session);
     /* start again */
-    GNUNET_free (ctc->type);
+    GNUNET_free (ctc->method);
     GNUNET_free (ctc);
     ctc = NULL;
     task = GNUNET_SCHEDULER_add_now (&run_aggregation,
@@ -953,7 +978,7 @@ prepare_close_cb (void *cls,
   /* Commit our intention to execute the wire transfer! */
   qs = db_plugin->wire_prepare_data_insert (db_plugin->cls,
 					    ctc->session,
-					    ctc->type,
+					    ctc->method,
 					    buf,
 					    buf_size);
   if (GNUNET_DB_STATUS_HARD_ERROR == qs)
@@ -963,7 +988,7 @@ prepare_close_cb (void *cls,
                          ctc->session);
     global_ret = GNUNET_SYSERR;
     GNUNET_SCHEDULER_shutdown ();
-    GNUNET_free (ctc->type);
+    GNUNET_free (ctc->method);
     GNUNET_free (ctc);
     ctc = NULL;
     return;
@@ -975,7 +1000,7 @@ prepare_close_cb (void *cls,
     /* start again */
     task = GNUNET_SCHEDULER_add_now (&run_aggregation,
                                      NULL);
-    GNUNET_free (ctc->type);
+    GNUNET_free (ctc->method);
     GNUNET_free (ctc);
     ctc = NULL;
     return;
@@ -983,7 +1008,7 @@ prepare_close_cb (void *cls,
 
   /* finally commit */
   (void) commit_or_warn (ctc->session);
-  GNUNET_free (ctc->type);
+  GNUNET_free (ctc->method);
   GNUNET_free (ctc);
   ctc = NULL;
   GNUNET_log (GNUNET_ERROR_TYPE_INFO,
@@ -1029,7 +1054,7 @@ static enum GNUNET_DB_QueryStatus
 expired_reserve_cb (void *cls,
 		    const struct TALER_ReservePublicKeyP *reserve_pub,
 		    const struct TALER_Amount *left,
-		    const json_t *account_details,
+		    const char *account_details,
 		    struct GNUNET_TIME_Absolute expiration_date)
 {
   struct ExpiredReserveContext *erc = cls;
@@ -1040,24 +1065,15 @@ expired_reserve_cb (void *cls,
   const struct TALER_Amount *closing_fee;
   int ret;
   enum GNUNET_DB_QueryStatus qs;
-  const char *type;
-  struct WirePlugin *wp;
+  struct WireAccount *wa;
 
   GNUNET_assert (NULL == ctc);
   now = GNUNET_TIME_absolute_get ();
   (void) GNUNET_TIME_round_abs (&now);
 
   /* lookup wire plugin */
-  type = extract_type (account_details);
-  if (NULL == type)
-  {
-    GNUNET_break (0);
-    global_ret = GNUNET_SYSERR;
-    GNUNET_SCHEDULER_shutdown ();
-    return GNUNET_DB_STATUS_HARD_ERROR;
-  }
-  wp = find_plugin (type);
-  if (NULL == wp)
+  wa = find_account_by_url (account_details);
+  if (NULL == wa)
   {
     GNUNET_break (0);
     global_ret = GNUNET_SYSERR;
@@ -1066,7 +1082,7 @@ expired_reserve_cb (void *cls,
   }
 
   /* lookup `closing_fee` */
-  qs = update_fees (wp,
+  qs = update_fees (wa,
 		    now,
 		    session);
   if (qs <= 0)
@@ -1079,7 +1095,7 @@ expired_reserve_cb (void *cls,
       GNUNET_SCHEDULER_shutdown ();
     return qs;
   }
-  closing_fee = &wp->af->closing_fee;
+  closing_fee = &wa->af->closing_fee;
 
   /* calculate transfer amount */
   ret = TALER_amount_subtract (&amount_without_fee,
@@ -1124,7 +1140,7 @@ expired_reserve_cb (void *cls,
   {
     /* success, perform wire transfer */
     if (GNUNET_SYSERR ==
-	wp->wire_plugin->amount_round (wp->wire_plugin->cls,
+	wa->wire_plugin->amount_round (wa->wire_plugin->cls,
 				       &amount_without_fee))
     {
       GNUNET_break (0);
@@ -1133,11 +1149,12 @@ expired_reserve_cb (void *cls,
       return GNUNET_DB_STATUS_HARD_ERROR;
     }
     ctc = GNUNET_new (struct CloseTransferContext);
-    ctc->wp = wp;
+    ctc->wa = wa;
     ctc->session = session;
-    ctc->type = GNUNET_strdup (type);
+    ctc->method = TALER_WIRE_payto_get_method (account_details);
     ctc->ph
-      = wp->wire_plugin->prepare_wire_transfer (wp->wire_plugin->cls,
+      = wa->wire_plugin->prepare_wire_transfer (wa->wire_plugin->cls,
+                                                wa->section_name,
 						account_details,
 						&amount_without_fee,
 						exchange_base_url,
@@ -1149,7 +1166,7 @@ expired_reserve_cb (void *cls,
       GNUNET_break (0);
       global_ret = GNUNET_SYSERR;
       GNUNET_SCHEDULER_shutdown ();
-      GNUNET_free (ctc->type);
+      GNUNET_free (ctc->method);
       GNUNET_free (ctc);
       ctc = NULL;
       return GNUNET_DB_STATUS_HARD_ERROR;
@@ -1398,7 +1415,7 @@ run_aggregation (void *cls)
                                &au->total_amount,
                                &au->wire_fee)) ||
        (GNUNET_SYSERR ==
-        au->wp->wire_plugin->amount_round (au->wp->wire_plugin->cls,
+        au->wa->wire_plugin->amount_round (au->wa->wire_plugin->cls,
                                            &au->final_amount)) ||
        ( (0 == au->final_amount.value) &&
          (0 == au->final_amount.fraction) ) )
@@ -1479,22 +1496,28 @@ run_aggregation (void *cls)
                 TALER_B2S (&au->merchant_pub));
     GNUNET_free (amount_s);
   }
-  au->ph = au->wp->wire_plugin->prepare_wire_transfer (au->wp->wire_plugin->cls,
-                                                       au->wire,
-                                                       &au->final_amount,
-                                                       exchange_base_url,
-                                                       &au->wtid,
-                                                       &prepare_cb,
-                                                       au);
+  {
+    char *url;
+
+    url = TALER_JSON_wire_to_payto (au->wire);
+    au->ph = au->wa->wire_plugin->prepare_wire_transfer (au->wa->wire_plugin->cls,
+                                                         au->wa->section_name,
+                                                         url,
+                                                         &au->final_amount,
+                                                         exchange_base_url,
+                                                         &au->wtid,
+                                                         &prepare_cb,
+                                                         au);
+    GNUNET_free (url);
+  }
   if (NULL == au->ph)
   {
-    GNUNET_break (0); /* why? how to best recover? */
+    /* something went very wrong, likely bad configuration,
+       abort */
     db_plugin->rollback (db_plugin->cls,
                          session);
     cleanup_au ();
-    /* start again */
-    task = GNUNET_SCHEDULER_add_now (&run_aggregation,
-                                     NULL);
+    GNUNET_SCHEDULER_shutdown ();
     return;
   }
   /* otherwise we continue with #prepare_cb(), see below */
@@ -1536,7 +1559,7 @@ prepare_cb (void *cls,
   /* Commit our intention to execute the wire transfer! */
   qs = db_plugin->wire_prepare_data_insert (db_plugin->cls,
 					    session,
-					    au->wp->type,
+					    au->wa->wire_plugin->method,
 					    buf,
 					    buf_size);
   /* Commit the WTID data to 'wire_out' to finally satisfy aggregation
@@ -1711,8 +1734,8 @@ wire_prepare_cb (void *cls,
   GNUNET_log (GNUNET_ERROR_TYPE_INFO,
               "Starting wire transfer %llu\n",
               (unsigned long long) rowid);
-  wpd->wp = find_plugin (wire_method);
-  if (NULL == wpd->wp)
+  wpd->wa = find_account_by_method (wire_method);
+  if (NULL == wpd->wa)
   {
     /* Should really never happen here, as when we get
        here the plugin should be in the cache. */
@@ -1725,7 +1748,7 @@ wire_prepare_cb (void *cls,
     wpd = NULL;
     return;
   }
-  wpd->eh = wpd->wp->wire_plugin->execute_wire_transfer (wpd->wp->wire_plugin->cls,
+  wpd->eh = wpd->wa->wire_plugin->execute_wire_transfer (wpd->wa->wire_plugin->cls,
                                                          buf,
                                                          buf_size,
                                                          &wire_confirm_cb,