introduce zero_limits for #9039/#9040 to signal clients that they must do KYC before even attempting to work with an exchange

7 files changed, 159 insertions, 0 deletions

diff --git a/src/exchange/taler-exchange-httpd.c b/src/exchange/taler-exchange-httpd.c
index 52e8ef6af..f45865381 100644
--- a/src/exchange/taler-exchange-httpd.c
+++ b/src/exchange/taler-exchange-httpd.c
@@ -176,6 +176,11 @@ float TEH_stefan_lin;
 json_t *TEH_hard_limits;
 
 /**
+ * JSON array with zero limits for /keys response.
+ */
+json_t *TEH_zero_limits;
+
+/**
  * Where to redirect users from "/"?
  */
 static char *toplevel_redirect_url;
@@ -2141,6 +2146,8 @@ exchange_serve_process_config (const char *cfg_fn)
   }
   TEH_hard_limits
     = TALER_KYCLOGIC_get_hard_limits ();
+  TEH_zero_limits
+    = TALER_KYCLOGIC_get_zero_limits ();
   if (GNUNET_OK !=
       GNUNET_CONFIGURATION_get_value_number (TEH_cfg,
                                              "exchange",
diff --git a/src/exchange/taler-exchange-httpd.h b/src/exchange/taler-exchange-httpd.h
index d6350c897..7f2233eab 100644
--- a/src/exchange/taler-exchange-httpd.h
+++ b/src/exchange/taler-exchange-httpd.h
@@ -103,6 +103,11 @@ extern struct TALER_EXCHANGEDB_Plugin *TEH_plugin;
 extern json_t *TEH_hard_limits;
 
 /**
+ * JSON array with zero limits for /keys response.
+ */
+extern json_t *TEH_zero_limits;
+
+/**
  * Absolute STEFAN parameter.
  */
 extern struct TALER_Amount TEH_stefan_abs;
diff --git a/src/exchange/taler-exchange-httpd_keys.c b/src/exchange/taler-exchange-httpd_keys.c
index e57e7d4f5..9998ccbbb 100644
--- a/src/exchange/taler-exchange-httpd_keys.c
+++ b/src/exchange/taler-exchange-httpd_keys.c
@@ -2416,6 +2416,9 @@ create_krd (struct TEH_KeyStateHandle *ksh,
     GNUNET_JSON_pack_array_incref (
       "hard_limits",
       TEH_hard_limits),
+    GNUNET_JSON_pack_array_incref (
+      "zero_limits",
+      TEH_zero_limits),
     TALER_JSON_pack_amount ("stefan_abs",
                             &TEH_stefan_abs),
     TALER_JSON_pack_amount ("stefan_log",
diff --git a/src/include/taler_exchange_service.h b/src/include/taler_exchange_service.h
index 3e6840266..b9b1f8778 100644
--- a/src/include/taler_exchange_service.h
+++ b/src/include/taler_exchange_service.h
@@ -450,6 +450,22 @@ struct TALER_EXCHANGE_WireAccount
 
 
 /**
+ * Applicable soft limits of zero for an account (or wallet).
+ * Clients should begin a KYC process before attempting
+ * these operations.
+ */
+struct TALER_EXCHANGE_ZeroLimitedOperation
+{
+
+  /**
+   * Operation type for which the restriction applies.
+   */
+  enum TALER_KYCLOGIC_KycTriggerEvent operation_type;
+
+};
+
+
+/**
  * Applicable limits for an account (or wallet). Exceeding these limits may
  * trigger additional KYC requirements or be categorically verboten.
  */
@@ -569,6 +585,14 @@ struct TALER_EXCHANGE_Keys
   struct TALER_EXCHANGE_AccountLimit *hard_limits;
 
   /**
+   * Array of operations with a default soft limit of zero
+   * that apply at this exchange.
+   * Clients should begin a KYC process before attempting
+   * these operations.
+   */
+  struct TALER_EXCHANGE_ZeroLimitedOperation *zero_limits;
+
+  /**
    * Array of wire fees by wire method.
    */
   struct TALER_EXCHANGE_WireFeesByMethod *fees;
@@ -638,6 +662,11 @@ struct TALER_EXCHANGE_Keys
   unsigned int hard_limits_length;
 
   /**
+   * Length of @e zero_limits array.
+   */
+  unsigned int zero_limits_length;
+
+  /**
    * Length of the @e wallet_balance_limit_without_kyc
    * array.
    */
diff --git a/src/include/taler_kyclogic_lib.h b/src/include/taler_kyclogic_lib.h
index 17ca2fe04..2387ac074 100644
--- a/src/include/taler_kyclogic_lib.h
+++ b/src/include/taler_kyclogic_lib.h
@@ -370,6 +370,19 @@ TALER_KYCLOGIC_get_hard_limits (void);
 
 
 /**
+ * Return JSON array of ZeroLimitedOperation objects with
+ * operations for which this exchange has a limit
+ * of zero, that means KYC is always required (or
+ * the operation is categorically forbidden).
+ *
+ * @return the JSON array of ZeroLimitedOperation objects,
+ *   empty array if there are no hard limits
+ */
+json_t *
+TALER_KYCLOGIC_get_zero_limits (void);
+
+
+/**
  * Get human-readable name of KYC rule.
  *
  * @param r rule to convert
diff --git a/src/kyclogic/kyclogic_api.c b/src/kyclogic/kyclogic_api.c
index 5f5b45f92..16cd16c72 100644
--- a/src/kyclogic/kyclogic_api.c
+++ b/src/kyclogic/kyclogic_api.c
@@ -3585,4 +3585,37 @@ TALER_KYCLOGIC_get_hard_limits ()
 }
 
 
+json_t *
+TALER_KYCLOGIC_get_zero_limits ()
+{
+  const struct TALER_KYCLOGIC_KycRule *rules
+    = default_rules.kyc_rules;
+  unsigned int num_rules
+    = default_rules.num_kyc_rules;
+  json_t *zero_limits;
+
+  zero_limits = json_array ();
+  GNUNET_assert (NULL != zero_limits);
+  for (unsigned int i = 0; i<num_rules; i++)
+  {
+    const struct TALER_KYCLOGIC_KycRule *rule = &rules[i];
+    json_t *zero_limit;
+
+    if (! rule->exposed)
+      continue;
+    if (rule->verboten)
+      continue; /* see: hard_limits */
+    if (! TALER_amount_is_zero (&rule->threshold))
+      continue;
+    zero_limit = GNUNET_JSON_PACK (
+      TALER_JSON_pack_kycte ("operation_type",
+                             rule->trigger));
+    GNUNET_assert (0 ==
+                   json_array_append_new (zero_limits,
+                                          zero_limit));
+  }
+  return zero_limits;
+}
+
+
 /* end of kyclogic_api.c */
diff --git a/src/lib/exchange_api_handle.c b/src/lib/exchange_api_handle.c
index 329e2c2e6..c39440857 100644
--- a/src/lib/exchange_api_handle.c
+++ b/src/lib/exchange_api_handle.c
@@ -813,6 +813,57 @@ parse_hard_limits (const json_t *hard_limits,
 
 
 /**
+ * Decode the JSON array in @a zero_limits from the /keys response
+ * and store the data in `zero_limits` array the @a key_data.
+ *
+ * @param[in] zero_limits JSON array to parse
+ * @param[out] key_data where to store the results we decoded
+ * @return #GNUNET_OK on success, #GNUNET_SYSERR on error
+ * (malformed JSON)
+ */
+static enum GNUNET_GenericReturnValue
+parse_zero_limits (const json_t *zero_limits,
+                   struct TALER_EXCHANGE_Keys *key_data)
+{
+  json_t *obj;
+  size_t off;
+
+  key_data->zero_limits_length
+    = (unsigned int) json_array_size (zero_limits);
+  if ( ((size_t) key_data->zero_limits_length)
+       != json_array_size (zero_limits))
+  {
+    GNUNET_break (0);
+    return GNUNET_SYSERR;
+  }
+  key_data->zero_limits
+    = GNUNET_new_array (key_data->zero_limits_length,
+                        struct TALER_EXCHANGE_ZeroLimitedOperation);
+
+  json_array_foreach (zero_limits, off, obj)
+  {
+    struct TALER_EXCHANGE_ZeroLimitedOperation *zol
+      = &key_data->zero_limits[off];
+    struct GNUNET_JSON_Specification spec[] = {
+      TALER_JSON_spec_kycte ("operation_type",
+                             &zol->operation_type),
+      GNUNET_JSON_spec_end ()
+    };
+
+    if (GNUNET_OK !=
+        GNUNET_JSON_parse (obj,
+                           spec,
+                           NULL, NULL))
+    {
+      GNUNET_break_op (0);
+      return GNUNET_SYSERR;
+    }
+  }
+  return GNUNET_OK;
+}
+
+
+/**
  * Decode the JSON in @a resp_obj from the /keys response
  * and store the data in the @a key_data.
  *
@@ -976,6 +1027,7 @@ decode_keys_json (const json_t *resp_obj,
     }
     {
       const json_t *hard_limits = NULL;
+      const json_t *zero_limits = NULL;
       struct GNUNET_JSON_Specification sspec[] = {
         TALER_JSON_spec_currency_specification (
           "currency_specification",
@@ -994,6 +1046,11 @@ decode_keys_json (const json_t *resp_obj,
             "hard_limits",
             &hard_limits),
           NULL),
+        GNUNET_JSON_spec_mark_optional (
+          GNUNET_JSON_spec_array_const (
+            "zero_limits",
+            &zero_limits),
+          NULL),
         GNUNET_JSON_spec_double (
           "stefan_lin",
           &key_data->stefan_lin),
@@ -1021,6 +1078,15 @@ decode_keys_json (const json_t *resp_obj,
                     "Parsing hard limits of /keys failed\n");
         EXITIF (1);
       }
+      if ( (NULL != zero_limits) &&
+           (GNUNET_OK !=
+            parse_zero_limits (zero_limits,
+                               key_data)) )
+      {
+        GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
+                    "Parsing hard limits of /keys failed\n");
+        EXITIF (1);
+      }
     }
 
     key_data->currency = GNUNET_strdup (currency);
@@ -1964,6 +2030,9 @@ TALER_EXCHANGE_keys_decref (struct TALER_EXCHANGE_Keys *keys)
   GNUNET_array_grow (keys->hard_limits,
                      keys->hard_limits_length,
                      0);
+  GNUNET_array_grow (keys->zero_limits,
+                     keys->zero_limits_length,
+                     0);
   json_decref (keys->extensions);
   GNUNET_free (keys->cspec.name);
   json_decref (keys->cspec.map_alt_unit_names);