refinements of policy extension APIs

src/exchange/taler-exchange-httpd_deposit.c

@@ -114,6 +114,11 @@ struct DepositContext
    */
   const struct TALER_EXCHANGEDB_Deposit *deposit;
 
+  /**
+   * Extension handler for policy, maybe NULL.
+   */
+  const struct TALER_Extension *policy_extension;
+
   /**
    * Our timestamp (when we received the request).
    * Possibly updated by the transaction if the
@@ -156,6 +161,7 @@ deposit_transaction (void *cls,
   enum GNUNET_DB_QueryStatus qs;
   bool balance_ok;
   bool in_conflict;
+  bool blocked_by_policy = false;
 
   qs = TEH_make_coin_known (&dc->deposit->coin,
                             connection,
@@ -163,11 +169,30 @@ deposit_transaction (void *cls,
                             mhd_ret);
   if (qs < 0)
     return qs;
+
+  /* Check and apply policies, if applicable */
+  if (NULL != dc->policy_extension)
+  {
+    const struct TALER_Extension *ext = dc->policy_extension;
+    struct TALER_ExtensionsPolicySerialID serialID;
+    struct GNUNET_TIME_Timestamp deadline;
+    GNUNET_assert (ext->parse_policy_details);
+
+    qs = ext->parse_policy_details (dc->deposit->policy_details,
+                                    &serialID,
+                                    &deadline);
+
+    if (qs < 0)
+      return qs;
+
+    blocked_by_policy = true;
+  }
+
   qs = TEH_plugin->do_deposit (TEH_plugin->cls,
                                dc->deposit,
                                dc->known_coin_id,
                                &dc->h_payto,
-                               false, /* FIXME-OEC: extension blocked #7270 */
+                               blocked_by_policy,
                                &dc->exchange_timestamp,
                                &balance_ok,
                                &in_conflict);
@@ -208,86 +233,6 @@ deposit_transaction (void *cls,
 }
 
 
-/**
- * @brief check the provided policy
- *
- * @param[in] policy_details JSON object provided by the client with prolicy
- * @param[out] hc On success, will contain the hash of the normalized policy_details object
- * @param[out] handler_out On success, the handler might provide an output
- * @param[out] error_hint On failure, might contain a hint of the error from the extension
- * @return GNUNET_OK on success.
- */
-enum GNUNET_GenericReturnValue
-check_policy_details (
-  json_t *policy_details,
-  struct TALER_ExtensionPolicyHashP *hc,
-  json_t **handler_out,
-  char **error_hint)
-{
-  const char *type = NULL;
-  const struct TALER_Extension *extension;
-  enum GNUNET_GenericReturnValue ret;
-
-  *error_hint  = NULL;
-
-  if ((NULL == policy_details) ||
-      (! json_is_object (policy_details)))
-  {
-    *error_hint = "invalid policy object";
-    return GNUNET_SYSERR;
-  }
-
-  // parse and evaluate the object
-  {
-    json_t *jtype = json_object_get (
-      policy_details,
-      "type");
-    if (NULL == jtype)
-    {
-      *error_hint = "no type in policy object";
-      return GNUNET_SYSERR;
-    }
-
-    type = json_string_value (jtype);
-    if (NULL == type)
-    {
-      *error_hint = "invalid type in policy object";
-      return GNUNET_SYSERR;
-    }
-
-    extension = TALER_extensions_get_by_name (type);
-    if ((NULL == extension) ||
-        (NULL == extension->deposit_handler))
-    {
-      GNUNET_break (0);
-      *error_hint = "no such policy";
-      return GNUNET_SYSERR;
-    }
-
-    ret = extension->deposit_handler (policy_details,
-                                      handler_out);
-    if (GNUNET_OK != ret)
-    {
-      GNUNET_break (0);
-      if (NULL != *handler_out)
-      {
-        *error_hint = json_dumps (*handler_out, JSON_INDENT (2));
-      }
-      else
-      {
-        GNUNET_break (1);
-        *error_hint = "unknown error with the policy";
-      }
-      return ret;
-    }
-  }
-
-  TALER_deposit_policy_hash (policy_details,
-                             hc);
-  return GNUNET_OK;
-}
-
-
 MHD_RESULT
 TEH_handler_deposit (struct MHD_Connection *connection,
                      const struct TALER_CoinSpendPublicKeyP *coin_pub,
@@ -296,9 +241,7 @@ TEH_handler_deposit (struct MHD_Connection *connection,
   struct DepositContext dc;
   struct TALER_EXCHANGEDB_Deposit deposit;
   const char *payto_uri;
-  struct TALER_ExtensionPolicyHashP h_policy;
   struct TALER_ExtensionPolicyHashP *ph_policy = NULL;
-  bool no_policy;
   struct GNUNET_JSON_Specification spec[] = {
     GNUNET_JSON_spec_string ("merchant_payto_uri",
                              &payto_uri),
@@ -311,8 +254,6 @@ TEH_handler_deposit (struct MHD_Connection *connection,
                                  &deposit.coin.denom_pub_hash),
     TALER_JSON_spec_denom_sig ("ub_sig",
                                &deposit.coin.denom_sig),
-    GNUNET_JSON_spec_fixed_auto ("merchant_pub",
-                                 &deposit.merchant_pub),
     GNUNET_JSON_spec_fixed_auto ("h_contract_terms",
                                  &deposit.h_contract_terms),
     GNUNET_JSON_spec_mark_optional (
@@ -324,17 +265,20 @@ TEH_handler_deposit (struct MHD_Connection *connection,
     GNUNET_JSON_spec_timestamp ("timestamp",
                                 &deposit.timestamp),
 
-    /* TODO: this will move to an extension for refunds */
+    /* TODO: refund_deadline and merchant_pub will move into the
+     * extension policy_merchant_refunds */
     GNUNET_JSON_spec_mark_optional (
       GNUNET_JSON_spec_timestamp ("refund_deadline",
                                   &deposit.refund_deadline),
       NULL),
+    GNUNET_JSON_spec_fixed_auto ("merchant_pub",
+                                 &deposit.merchant_pub),
+    GNUNET_JSON_spec_timestamp ("wire_transfer_deadline",
+                                &deposit.wire_deadline),
     GNUNET_JSON_spec_mark_optional (
       GNUNET_JSON_spec_json ("policy",
                              &deposit.policy_details),
-      &no_policy),
+      &deposit.no_policy_details),
-    GNUNET_JSON_spec_timestamp ("wire_transfer_deadline",
-                                &deposit.wire_deadline),
     GNUNET_JSON_spec_end ()
   };
   struct TALER_MerchantWireHashP h_wire;
@@ -472,29 +416,11 @@ TEH_handler_deposit (struct MHD_Connection *connection,
                                          NULL);
     }
 
-    /* TODO: check policy_details */
+    if (! deposit.no_policy_details)
-    if (! no_policy)
     {
-      char *hint;
+      TALER_deposit_policy_hash (deposit.policy_details,
-      json_t *out;
+                                 &deposit.h_policy);
-      MHD_RESULT res;
+      ph_policy = &deposit.h_policy;
-
-      if (GNUNET_OK !=
-          check_policy_details (dc.deposit->policy_details,
-                                &h_policy,
-                                &out,
-                                &hint))
-      {
-        res = TALER_MHD_reply_with_error (connection,
-                                          MHD_HTTP_BAD_REQUEST,
-                                          /* TODO: new error type needed */
-                                          TALER_EC_EXCHANGE_GENERIC_OPERATION_UNKNOWN,
-                                          hint);
-        GNUNET_free (hint);
-        return res;
-      }
-
-      ph_policy = &h_policy;
     }
 
     deposit.deposit_fee = dk->meta.fees.deposit;

src/extensions/age_restriction/age_restriction.c

@@ -151,7 +151,9 @@ struct TALER_Extension TE_age_restriction = {
   .disable = &age_restriction_disable,
   .load_config = &age_restriction_load_config,
   .manifest = &age_restriction_manifest,
-  .deposit_handler = NULL,
+
+  /* This extension is not a policy extension */
+  .parse_policy_details = NULL,
   .http_get_handler = NULL,
   .http_post_handler = NULL,
 };

src/extensions/extensions.c

@@ -353,4 +353,53 @@ TALER_extensions_load_manifests (
 }
 
 
+enum GNUNET_GenericReturnValue
+TALER_extensions_from_policy_details (
+  const json_t *policy_details,
+  const struct TALER_Extension **extension,
+  char **error_hint)
+{
+  const json_t *jtype;
+  const char *type;
+
+  *extension = NULL;
+  *error_hint = NULL;
+
+  if ((NULL == policy_details) ||
+      (! json_is_object (policy_details)))
+  {
+    *error_hint = "invalid policy object";
+    return GNUNET_SYSERR;
+  }
+
+  jtype = json_object_get (policy_details, "type");
+  if (NULL == jtype)
+  {
+    *error_hint = "no type in policy object";
+    return GNUNET_SYSERR;
+  }
+
+  type = json_string_value (jtype);
+  if (NULL == type)
+  {
+    *error_hint = "invalid type in policy object";
+    return GNUNET_SYSERR;
+  }
+
+  *extension = TALER_extensions_get_by_name (type);
+  if ((NULL == *extension) ||
+      (NULL == (*extension)->parse_policy_details))
+  {
+    GNUNET_break (0);
+    GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
+                "Unsupported extension policy '%s' requested\n",
+                type);
+    *extension = NULL;
+    return GNUNET_NO;
+  }
+
+  return GNUNET_OK;
+}
+
+
 /* end of extensions.c */

src/extensions/policy_brandt_vickrey_auction/policy_brandt_vickrey_auction.c

@@ -1,6 +1,6 @@
 /*
    This file is part of TALER
-   Copyright (C) 2021-2022 Taler Systems SA
+   Copyright (C) 2022 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
@@ -32,7 +32,7 @@
 
 /* (public) configuration of this extension */
 /* TODO: these fields need to be set in the init handler */
-static struct TALER_BrandtVickreyAuction BV_config = {
+static struct TALER_ExtensionPolicyBrandtVickreyAuctionConfig BV_config = {
   .max_bidders = 10,
   .max_prices = 10,
   .auction_fee = {
@@ -497,7 +497,7 @@ static json_t *
 auction_manifest (
   const struct TALER_Extension *ext)
 {
-  struct TALER_BrandtVickreyAuction *conf = ext->config;
+  struct TALER_ExtensionPolicyBrandtVickreyAuctionConfig *conf = ext->config;
   GNUNET_assert (conf);
 
   json_t *config = GNUNET_JSON_PACK (
@@ -589,20 +589,66 @@ auction_http_post_handler (
 
 
 /**
- * @brief implements the TALER_Extensions.deposit_handler interface.
+ * @brief implements the TALER_Extensions.parse_policy_details interface.
  *
- * @param[in] input JSON input from the client during a deposit request
+ * @param[in] input The policy_details for this handler during deposit
- * @param[out] output by this extension
+ * @param[out] serial On success will contain the serial-ID under which the
+ * @param[out] deadline On success will contain a deadline, might be "forever"
+ * exchange should store the policy_details in the policy_details table.
  * @return GNUNET_OK if the request was OK
  */
 enum GNUNET_GenericReturnValue
-auction_deposit_handler (
+auction_parse_policy_details (
-  json_t *input,
+  const json_t *input,
-  json_t **output)
+  struct TALER_ExtensionsPolicySerialID *serial,
+  struct GNUNET_TIME_Timestamp *deadline)
 {
-  /* TODO */
+  enum GNUNET_GenericReturnValue ret = GNUNET_NO;
-  *output = NULL;
+  struct GNUNET_CRYPTO_EddsaPublicKey pub;
-  return GNUNET_OK;
+  struct GNUNET_HashCode hc;
+  struct GNUNET_JSON_Specification spec[] = {
+    /* We ignore the "type" field as it must have been parsed already upstream
+     * - or this handler wouldn't have been called in first place. */
+    GNUNET_JSON_spec_fixed_auto ("bidder_pub", &pub),
+    GNUNET_JSON_spec_fixed_auto ("h_auction", &hc),
+    GNUNET_JSON_spec_timestamp ("deadline", deadline),
+    GNUNET_JSON_spec_end (),
+  };
+
+  GNUNET_assert (serial);
+  GNUNET_assert (deadline);
+
+  do {
+    ret = GNUNET_JSON_parse (input,
+                             spec,
+                             NULL,
+                             NULL);
+
+    if (GNUNET_OK != ret)
+      break;
+
+    /* FIXME: check the deadline */
+    GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
+                LOG_PREFIX "check of deadline %ld not implemented!\n",
+                deadline->abs_time.abs_value_us);
+
+    /* Create serial as H(bidder_pub, h_auction) */
+    {
+      struct GNUNET_HashContext *hc = GNUNET_CRYPTO_hash_context_start ();
+      GNUNET_CRYPTO_hash_context_read (hc,
+                                       &pub,
+                                       sizeof(pub));
+      GNUNET_CRYPTO_hash_context_read (hc,
+                                       &hc,
+                                       sizeof(hc));
+      GNUNET_CRYPTO_hash_context_finish (hc,
+                                         &serial->hash);
+    }
+
+    ret = GNUNET_OK;
+  } while(0);
+
+  return ret;
 }
 
 
@@ -617,7 +663,7 @@ struct TALER_Extension TE_auction_brandt = {
   .disable = &auction_disable,
   .load_config = &auction_load_config,
   .manifest = &auction_manifest,
-  .deposit_handler = &auction_deposit_handler,
+  .parse_policy_details = &auction_parse_policy_details,
   .http_get_handler = &auction_http_get_handler,
   .http_post_handler = &auction_http_post_handler,
 };

src/include/taler_extensions.h

@@ -25,17 +25,21 @@
 #include "taler_crypto_lib.h"
 #include "taler_json_lib.h"
 #include "taler_mhd_lib.h"
+#include "taler_exchangedb_plugin.h"
 
 
 #define TALER_EXTENSION_SECTION_PREFIX "exchange-extension-"
 
 enum TALER_Extension_Type
 {
-  TALER_Extension_AgeRestriction             = 0,
+  TALER_Extension_PolicyNull                 = 0,
-  TALER_Extension_PolicyMerchantRefund       = 1,
+
-  TALER_Extension_PolicyBrandtVickeryAuction = 2,
+  TALER_Extension_AgeRestriction             = 1,
-  TALER_Extension_PolicyEscrowedPayment      = 3,
+  TALER_Extension_PolicyMerchantRefund       = 2,
-  TALER_Extension_MaxPredefined              = 4 // Must be last of the predefined
+  TALER_Extension_PolicyBrandtVickeryAuction = 3,
+  TALER_Extension_PolicyEscrowedPayment      = 4,
+
+  TALER_Extension_MaxPredefined              = 5 // Must be last of the predefined
 };
 
 
@@ -49,6 +53,15 @@ struct TALER_Extensions
   const struct TALER_Extension *extension;
 };
 
+/*
+ * @brief Serial ID under which the policy details to an deposit are stored in
+ * the policy_details table.
+ */
+struct TALER_ExtensionsPolicySerialID
+{
+  struct GNUNET_HashCode hash;
+};
+
 /*
  * @brief Represents the implementation of an extension.
  *
@@ -151,22 +164,30 @@ struct TALER_Extension
   json_t *(*manifest)(
     const struct TALER_Extension *ext);
 
+  /* =========================
+   *  Policy related handlers
+   * =========================
+   */
   /**
-   * @brief Handler for /{batch}-deposit requests.  Can be NULL.
+   * @brief Handler to check a policy. Can be NULL;
    *
    * When a deposit request refers to this extension in its policy
    * (see https://docs.taler.net/core/api-exchange.html#deposit), this handler
-   * will be called during the deposit operation.
+   * will be called before the deposit transaction.
    *
-   * @param[in] input The policy/extension specific data, provided by the client in
+   * @param[in] policy_details Details about the policy, provided by the client
-   * the policy-field of the deposit request.
+   * during a deposit request.
-   * @param[out] output Potential output by the extension to be provided to the
+   * @param[out] serial On success, will contain the serial-ID under which the
-   * client as part of the response to the deposit request.  Can be NULL.
+   * exchange should save the policy_details in the deposit table.
+   * @param[out] deadline On sucess, set to the deadline until the policy must
+   * be fulfilled.  Might be "forever".  This value is used by an external
+   * mechanism to detect timeouts.
    * @return GNUNET_OK if the data was accepted by the extension.
    */
-  enum GNUNET_GenericReturnValue (*deposit_handler)(
+  enum GNUNET_GenericReturnValue (*parse_policy_details)(
-    json_t *input,
+    const json_t *policy_details,
-    json_t **output);
+    struct TALER_ExtensionsPolicySerialID *serial,
+    struct GNUNET_TIME_Timestamp *deadline);
 
   /**
    * @brief Handler for POST-requests to the /policy/$name endpoint. Can be NULL.
@@ -366,19 +387,65 @@ struct TALER_AgeMask
 TALER_extensions_get_age_restriction_mask ();
 
 
+/*
+ * ===================================
+ * Policy extensions related functions
+ * ===================================
+ */
+
+/*
+ * @brief Finds the extension for a given policy
+ *
+ * @param[in]  policy_details JSON of the policy detail from a deposit request
+ * @param[out] extension On GNUNET_OK, the exentions handling the given policy
+ * @param[out] error_hint On GNUNET_SYSERR, will contain a hint for the reason why it failed
+ * @return GNUNET_OK on success, with *extension set to the correct extension.
+ * GNUNET_NO, when no extension was found. GNUNET_SYSERR when the JSON was
+ * invalid, with *error_hint maybe non-NULL.
+ */
+enum GNUNET_GenericReturnValue
+TALER_extensions_from_policy_details (
+  const json_t *policy_details,
+  const struct TALER_Extension **extension,
+  char **error_hint);
+
 /*
  * ================================
- * Brandt-Vickrey Auctions
+ * Merchant refund policy
+ * ================================
+ */
+struct TALER_ExtensionPolicyMerchantRefundPolicyConfig
+{
+  struct GNUNET_TIME_Relative max_timeout;
+};
+
+/*
+ * ================================
+ * Brandt-Vickrey Auctions policy
  * ================================
  */
 /*
- * @brief Configuration for Brandt-Vickrey auctions
+ * @brief Configuration for Brandt-Vickrey auctions policy
  */
-struct TALER_BrandtVickreyAuction
+struct TALER_ExtensionPolicyBrandtVickreyAuctionConfig
 {
   uint16_t max_bidders;
   uint16_t max_prices;
   struct TALER_Amount auction_fee;
 };
 
+
+/*
+ * ================================
+ * Escrowed Payments policy
+ * ================================
+ */
+/*
+ * @brief Configuration for escrowed payments policy
+ */
+struct TALER_ExtensionPolicyEscrowedPaymentsConfig
+{
+  struct GNUNET_TIME_Relative max_timeout;
+};
+
 #endif