start work on AML decision query API

contrib/gana

@@ -1 +1 @@
-Subproject commit 84a6023656a0acc8598950a65351a5d3526e84ae
+Subproject commit 14cb23ef0e31d3470a0671fe165a1557eddc0590

src/include/taler_crypto_lib.h

@@ -2370,6 +2370,31 @@ TALER_CRYPTO_contract_decrypt_for_deposit (
 
 /* **************** AML officer signatures **************** */
 
+/**
+ * Sign AML query. Simple authentication, doesn't actually
+ * sign anything.
+ *
+ * @param officer_priv private key of AML officer
+ * @param[out] officer_sig where to write the signature
+ */
+void
+TALER_officer_aml_query_sign (
+  const struct TALER_AmlOfficerPrivateKeyP *officer_priv,
+  struct TALER_AmlOfficerSignatureP *officer_sig);
+
+
+/**
+ * Verify AML query authorization.
+ *
+ * @param officer_pub public key of AML officer
+ * @param officer_sig signature to verify
+ * @return #GNUNET_OK if the signature is valid
+ */
+enum GNUNET_GenericReturnValue
+TALER_officer_aml_query_verify (
+  const struct TALER_AmlOfficerPublicKeyP *officer_pub,
+  const struct TALER_AmlOfficerSignatureP *officer_sig);
+
 
 /**
  * Sign AML decision.

src/lib/exchange_api_lookup_aml_decisions.c

@@ -0,0 +1,245 @@
+/*
+  This file is part of TALER
+  Copyright (C) 2023 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
+  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 General Public License for more details.
+
+  You should have received a copy of the GNU General Public License along with
+  TALER; see the file COPYING.  If not, see
+  <http://www.gnu.org/licenses/>
+*/
+/**
+ * @file lib/exchange_api_lookup_aml_decisions.c
+ * @brief Implementation of the /aml/$OFFICER_PUB/decisions request
+ * @author Christian Grothoff
+ */
+#include "platform.h"
+#include <microhttpd.h> /* just for HTTP status codes */
+#include <gnunet/gnunet_util_lib.h>
+#include <gnunet/gnunet_curl_lib.h>
+#include "taler_exchange_service.h"
+#include "taler_json_lib.h"
+#include "exchange_api_handle.h"
+#include "taler_signatures.h"
+#include "exchange_api_curl_defaults.h"
+
+
+/**
+ * @brief A /coins/$COIN_PUB/link Handle
+ */
+struct TALER_EXCHANGE_LookupAmlDecisions
+{
+
+  /**
+   * The url for this request.
+   */
+  char *url;
+
+  /**
+   * Handle for the request.
+   */
+  struct GNUNET_CURL_Job *job;
+
+  /**
+   * Function to call with the result.
+   */
+  TALER_EXCHANGE_LookupAmlDecisionsCallback decisions_cb;
+
+  /**
+   * Closure for @e cb.
+   */
+  void *decisions_cb_cls;
+
+};
+
+
+/**
+ * Parse the provided decision data from the "200 OK" response.
+ *
+ * @param[in,out] lh handle (callback may be zero'ed out)
+ * @param json json reply with the data for one coin
+ * @return #GNUNET_OK on success, #GNUNET_SYSERR on error
+ */
+static enum GNUNET_GenericReturnValue
+parse_decisions_ok (struct TALER_EXCHANGE_LookupAmlDecisions *lh,
+                    const json_t *json)
+{
+  struct TALER_EXCHANGE_AmlDecisionsResponse lr = {
+    .hr.reply = json,
+    .hr.http_status = MHD_HTTP_OK
+  };
+  int ret = GNUNET_SYSERR;
+
+  GNUNET_break (0); // FIXME: parse response!
+  return ret;
+}
+
+
+/**
+ * Function called when we're done processing the
+ * HTTP /aml/$OFFICER_PUB/decisions request.
+ *
+ * @param cls the `struct TALER_EXCHANGE_LookupAmlDecisions`
+ * @param response_code HTTP response code, 0 on error
+ * @param response parsed JSON result, NULL on error
+ */
+static void
+handle_lookup_finished (void *cls,
+                        long response_code,
+                        const void *response)
+{
+  struct TALER_EXCHANGE_LookupAmlDecisions *lh = cls;
+  const json_t *j = response;
+  struct TALER_EXCHANGE_LinkResult lr = {
+    .hr.reply = j,
+    .hr.http_status = (unsigned int) response_code
+  };
+
+  lh->job = NULL;
+  switch (response_code)
+  {
+  case 0:
+    lr.hr.ec = TALER_EC_GENERIC_INVALID_RESPONSE;
+    break;
+  case MHD_HTTP_OK:
+    if (GNUNET_OK !=
+        parse_decisions_ok (lh,
+                            j))
+    {
+      GNUNET_break_op (0);
+      lr.hr.http_status = 0;
+      lr.hr.ec = TALER_EC_GENERIC_REPLY_MALFORMED;
+      break;
+    }
+    GNUNET_assert (NULL == lh->decisions_cb);
+    TALER_EXCHANGE_link_cancel (lh);
+    return;
+  case MHD_HTTP_BAD_REQUEST:
+    lr.hr.ec = TALER_JSON_get_error_code (j);
+    lr.hr.hint = TALER_JSON_get_error_hint (j);
+    /* This should never happen, either us or the exchange is buggy
+       (or API version conflict); just pass JSON reply to the application */
+    break;
+  case MHD_HTTP_NOT_FOUND:
+    lr.hr.ec = TALER_JSON_get_error_code (j);
+    lr.hr.hint = TALER_JSON_get_error_hint (j);
+    /* Nothing really to verify, exchange says this coin was not melted; we
+       should pass the JSON reply to the application */
+    break;
+  case MHD_HTTP_INTERNAL_SERVER_ERROR:
+    lr.hr.ec = TALER_JSON_get_error_code (j);
+    lr.hr.hint = TALER_JSON_get_error_hint (j);
+    /* Server had an internal issue; we should retry, but this API
+       leaves this to the application */
+    break;
+  default:
+    /* unexpected response code */
+    GNUNET_break_op (0);
+    lr.hr.ec = TALER_JSON_get_error_code (j);
+    lr.hr.hint = TALER_JSON_get_error_hint (j);
+    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+                "Unexpected response code %u/%d for exchange link\n",
+                (unsigned int) response_code,
+                (int) lr.hr.ec);
+    break;
+  }
+  if (NULL != lh->decisions_cb)
+    lh->decisions_cb (lh->decisions_cb_cls,
+                      &lr);
+  TALER_EXCHANGE_link_cancel (lh);
+}
+
+
+struct TALER_EXCHANGE_LookupAmlDecisions *
+TALER_EXCHANGE_link (
+  struct GNUNET_CURL_Context *ctx,
+  const char *url,
+  uint64_t start,
+  int delta,
+  bool filter_frozen,
+  bool filter_pending,
+  bool filter_normal,
+  const struct TALER_AmlOfficerPrivateKeyP *officer_priv,
+  TALER_EXCHANGE_LookupAmlDecisionsCallback cb,
+  void *cb_cls)
+{
+  struct TALER_EXCHANGE_LookupAmlDecisions *lh;
+  CURL *eh;
+  struct TALER_AmlOfficerPublicKeyP officer_pub;
+  struct TALER_AmlOfficerSignatureP officer_sig;
+  char arg_str[sizeof (struct TALER_AmlOfficerPublicKeyP) * 2 + 32];
+
+  GNUNET_CRYPTO_eddsa_key_get_public (&officer_priv->eddsa_priv,
+                                      &officer_pub.eddsa_pub);
+  TALER_officer_aml_query_sign (officer_priv,
+                                &officer_sig);
+  {
+    char pub_str[sizeof (struct TALER_AmlOfficerPublicKeyP) * 2];
+    char *end;
+
+    end = GNUNET_STRINGS_data_to_string (
+      &officer_pub,
+      sizeof (officer_pub),
+      pub_str,
+      sizeof (pub_str));
+    *end = '\0';
+    GNUNET_snprintf (arg_str,
+                     sizeof (arg_str),
+                     "/aml/%s/decisions",
+                     pub_str);
+  }
+  lh = GNUNET_new (struct TALER_EXCHANGE_LookupAmlDecisions);
+  lh->decisions_cb = cb;
+  lh->decisions_cb_cls = cb_cls;
+  lh->url = TALER_URL_join (exchange_url,
+                            arg_str,
+                            "frozen",
+                            filter_fozen ? "yes" : NULL,
+                            "pending",
+                            filter_pending ? "yes" : NULL,
+                            "normal",
+                            filter_normal ? "yes" : NULL,
+                            NULL);
+  if (NULL == lh->url)
+  {
+    GNUNET_free (lh);
+    return NULL;
+  }
+  eh = TALER_EXCHANGE_curl_easy_get_ (lh->url);
+  if (NULL == eh)
+  {
+    GNUNET_break (0);
+    GNUNET_free (lh->url);
+    GNUNET_free (lh);
+    return NULL;
+  }
+  // FIXME: add authorization header to 'eh' based on officer_sig!
+  lh->job = GNUNET_CURL_job_add_with_ct_json (ctx,
+                                              eh,
+                                              &handle_lookup_finished,
+                                              lh);
+  return lh;
+}
+
+
+void
+TALER_EXCHANGE_lookup_aml_decisions (struct
+                                     TALER_EXCHANGE_LookupAmlDecisions *lh)
+{
+  if (NULL != lh->job)
+  {
+    GNUNET_CURL_job_cancel (lh->job);
+    lh->job = NULL;
+  }
+  GNUNET_free (lh->url);
+  GNUNET_free (lh);
+}
+
+
+/* end of exchange_api_lookup_aml_decisions.c */

src/util/aml_signatures.c

@@ -26,8 +26,7 @@
 GNUNET_NETWORK_STRUCT_BEGIN
 
 /**
- * @brief Format used to generate the signature on a request to deposit
+ * @brief Format used to generate the signature on an AML decision.
- * a coin into the account of a merchant.
  */
 struct TALER_AmlDecisionPS
 {
@@ -124,4 +123,63 @@ TALER_officer_aml_decision_verify (
 }
 
 
+GNUNET_NETWORK_STRUCT_BEGIN
+
+/**
+ * @brief Format used to generate the signature on any AML query.
+ */
+struct TALER_AmlQueryPS
+{
+  /**
+   * Purpose must be #TALER_SIGNATURE_AML_QUERY.
+   * Used for an EdDSA signature with the `struct TALER_AmlOfficerPublicKeyP`.
+   */
+  struct GNUNET_CRYPTO_EccSignaturePurpose purpose;
+
+};
+
+GNUNET_NETWORK_STRUCT_END
+
+
+void
+TALER_officer_aml_query_sign (
+  const struct TALER_AmlOfficerPrivateKeyP *officer_priv,
+  struct TALER_AmlOfficerSignatureP *officer_sig)
+{
+  struct TALER_AmlQueryPS aq = {
+    .purpose.purpose = htonl (TALER_SIGNATURE_AML_QUERY),
+    .purpose.size = htonl (sizeof (aq))
+  };
+
+  GNUNET_CRYPTO_eddsa_sign (&officer_priv->eddsa_priv,
+                            &aq,
+                            &officer_sig->eddsa_signature);
+}
+
+
+/**
+ * Verify AML query authorization.
+ *
+ * @param officer_pub public key of AML officer
+ * @param officer_sig signature to verify
+ * @return #GNUNET_OK if the signature is valid
+ */
+enum GNUNET_GenericReturnValue
+TALER_officer_aml_query_verify (
+  const struct TALER_AmlOfficerPublicKeyP *officer_pub,
+  const struct TALER_AmlOfficerSignatureP *officer_sig)
+{
+  struct TALER_AmlQueryPS aq = {
+    .purpose.purpose = htonl (TALER_SIGNATURE_AML_QUERY),
+    .purpose.size = htonl (sizeof (aq))
+  };
+
+  return GNUNET_CRYPTO_eddsa_verify (
+    TALER_SIGNATURE_AML_QUERY,
+    &aq,
+    &officer_sig->eddsa_signature,
+    &officer_pub->eddsa_pub);
+}
+
+
 /* end of aml_signatures.c */