starting with purse creation client API

1 files changed, 410 insertions, 0 deletions

diff --git a/src/lib/exchange_api_purse_create_with_deposit.c b/src/lib/exchange_api_purse_create_with_deposit.c
new file mode 100644
index 000000000..6765b7771
--- /dev/null
+++ b/src/lib/exchange_api_purse_create_with_deposit.c
@@ -0,0 +1,410 @@
+/*
+   This file is part of TALER
+   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
+   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_purse_create_with_deposit.c
+ * @brief Implementation of the client to create a purse with
+ *        an initial set of deposits (and a contract)
+ * @author Christian Grothoff
+ */
+#include "platform.h"
+#include <jansson.h>
+#include <microhttpd.h> /* just for HTTP status codes */
+#include <gnunet/gnunet_util_lib.h>
+#include <gnunet/gnunet_json_lib.h>
+#include <gnunet/gnunet_curl_lib.h>
+#include "taler_json_lib.h"
+#include "taler_exchange_service.h"
+#include "exchange_api_handle.h"
+#include "taler_signatures.h"
+#include "exchange_api_curl_defaults.h"
+
+
+/**
+ * @brief A purse create with deposit handle
+ */
+struct TALER_EXCHANGE_PurseCreateDepositHandle
+{
+
+  /**
+   * The connection to exchange this request handle will use
+   */
+  struct TALER_EXCHANGE_Handle *exchange;
+
+  /**
+   * The url for this request.
+   */
+  char *url;
+
+  /**
+   * Context for #TEH_curl_easy_post(). Keeps the data that must
+   * persist for Curl to make the upload.
+   */
+  struct TALER_CURL_PostContext ctx;
+
+  /**
+   * Handle for the request.
+   */
+  struct GNUNET_CURL_Job *job;
+
+  /**
+   * Function to call with the result.
+   */
+  TALER_EXCHANGE_PurseCreateDepositCallback cb;
+
+  /**
+   * Closure for @a cb.
+   */
+  void *cb_cls;
+
+};
+
+
+/**
+ * Function called when we're done processing the
+ * HTTP /deposit request.
+ *
+ * @param cls the `struct TALER_EXCHANGE_DepositHandle`
+ * @param response_code HTTP response code, 0 on error
+ * @param response parsed JSON result, NULL on error
+ */
+static void
+handle_purse_create_deposit_finished (void *cls,
+                                      long response_code,
+                                      const void *response)
+{
+  struct TALER_EXCHANGE_PurseCreateDepositHandle *pch = cls;
+  const json_t *j = response;
+  struct TALER_EXCHANGE_PurseCreateDepositResponse dr = {
+    .hr.reply = j,
+    .hr.http_status = (unsigned int) response_code
+  };
+
+  pch->job = NULL;
+  switch (response_code)
+  {
+  case 0:
+    dr.hr.ec = TALER_EC_GENERIC_INVALID_RESPONSE;
+    break;
+  case MHD_HTTP_OK:
+    {
+      const struct TALER_EXCHANGE_Keys *key_state;
+      struct GNUNET_JSON_Specification spec[] = {
+#if 0
+        GNUNET_JSON_spec_fixed_auto ("exchange_sig",
+                                     &pch->exchange_sig),
+        GNUNET_JSON_spec_fixed_auto ("exchange_pub",
+                                     &pch->exchange_pub),
+#endif
+        GNUNET_JSON_spec_end ()
+      };
+
+      if (GNUNET_OK !=
+          GNUNET_JSON_parse (j,
+                             spec,
+                             NULL, NULL))
+      {
+        GNUNET_break_op (0);
+        dr.hr.http_status = 0;
+        dr.hr.ec = TALER_EC_GENERIC_REPLY_MALFORMED;
+        break;
+      }
+      key_state = TALER_EXCHANGE_get_keys (pch->exchange);
+#if 0
+      if (GNUNET_OK !=
+          TALER_EXCHANGE_test_signing_key (key_state,
+                                           &exchange_pub))
+      {
+        GNUNET_break_op (0);
+        dr.hr.http_status = 0;
+        dr.hr.ec =
+          TALER_EC_EXCHANGE_PURSE_CREATE_WITH_DEPOSIT_INVALID_SIGNATURE_BY_EXCHANGE;
+        break;
+      }
+#endif
+      // FIXME: validate reply...
+      (void) key_state;
+    }
+    break;
+  case MHD_HTTP_BAD_REQUEST:
+    /* This should never happen, either us or the exchange is buggy
+       (or API version conflict); just pass JSON reply to the application */
+    dr.hr.ec = TALER_JSON_get_error_code (j);
+    dr.hr.hint = TALER_JSON_get_error_hint (j);
+    break;
+  case MHD_HTTP_FORBIDDEN:
+    dr.hr.ec = TALER_JSON_get_error_code (j);
+    dr.hr.hint = TALER_JSON_get_error_hint (j);
+    /* Nothing really to verify, exchange says one of the signatures is
+       invalid; as we checked them, this should never happen, we
+       should pass the JSON reply to the application */
+    break;
+  case MHD_HTTP_NOT_FOUND:
+    dr.hr.ec = TALER_JSON_get_error_code (j);
+    dr.hr.hint = TALER_JSON_get_error_hint (j);
+    /* Nothing really to verify, this should never
+       happen, we should pass the JSON reply to the application */
+    break;
+  case MHD_HTTP_CONFLICT:
+    // FIXME: check reply?
+    break;
+  case MHD_HTTP_GONE:
+    /* could happen if denomination was revoked */
+    /* Note: one might want to check /keys for revocation
+       signature here, alas tricky in case our /keys
+       is outdated => left to clients */
+    dr.hr.ec = TALER_JSON_get_error_code (j);
+    dr.hr.hint = TALER_JSON_get_error_hint (j);
+    break;
+  case MHD_HTTP_INTERNAL_SERVER_ERROR:
+    dr.hr.ec = TALER_JSON_get_error_code (j);
+    dr.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 */
+    dr.hr.ec = TALER_JSON_get_error_code (j);
+    dr.hr.hint = TALER_JSON_get_error_hint (j);
+    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+                "Unexpected response code %u/%d for exchange deposit\n",
+                (unsigned int) response_code,
+                dr.hr.ec);
+    GNUNET_break_op (0);
+    break;
+  }
+  pch->cb (pch->cb_cls,
+           &dr);
+  TALER_EXCHANGE_purse_create_with_deposit_cancel (pch);
+}
+
+
+struct TALER_EXCHANGE_PurseCreateDepositHandle *
+TALER_EXCHANGE_purse_create_with_deposit (
+  struct TALER_EXCHANGE_Handle *exchange,
+  const struct TALER_PurseContractPrivateKeyP *purse_priv,
+  const struct TALER_PurseMergePrivateKeyP *merge_priv,
+  const struct TALER_ContractDiffiePrivateP *contract_priv,
+  const json_t *contract_terms,
+  struct GNUNET_TIME_Timestamp purse_expiration,
+  unsigned int num_deposits,
+  const struct TALER_EXCHANGE_PurseDeposit *deposits,
+  TALER_EXCHANGE_PurseCreateDepositCallback cb,
+  void *cb_cls)
+{
+  struct TALER_EXCHANGE_PurseCreateDepositHandle *pch;
+  struct GNUNET_CURL_Context *ctx;
+  json_t *create_obj;
+  json_t *deposit_arr;
+  CURL *eh;
+  struct TALER_PurseMergePublicKeyP merge_pub;
+  struct TALER_PurseContractPublicKeyP purse_pub;
+  struct TALER_ContractDiffiePublicP contract_pub;
+  struct TALER_PrivateContractHashP h_contract_terms;
+  char arg_str[sizeof (purse_pub) * 2 + 32];
+  char *url;
+  uint32_t min_age;
+  struct TALER_Amount purse_value_after_fees;
+  struct GNUNET_JSON_Specification spec[] = {
+    TALER_JSON_spec_amount_any ("amount",
+                                &purse_value_after_fees),
+    GNUNET_JSON_spec_mark_optional (
+      GNUNET_JSON_spec_uint32 ("minimum_age",
+                               &min_age)),
+    GNUNET_JSON_spec_end ()
+  };
+
+  if (GNUNET_OK !=
+      GNUNET_JSON_parse (contract_terms,
+                         spec,
+                         NULL, NULL))
+  {
+    GNUNET_break (0);
+    return NULL;
+  }
+  GNUNET_assert (GNUNET_YES ==
+                 TEAH_handle_is_ready (exchange));
+  if (GNUNET_OK !=
+      TALER_JSON_contract_hash (contract_terms,
+                                &h_contract_terms))
+  {
+    GNUNET_break (0);
+    return NULL;
+  }
+  GNUNET_CRYPTO_eddsa_key_get_public (&purse_priv->eddsa_priv,
+                                      &purse_pub.eddsa_pub);
+  {
+    char pub_str[sizeof (purse_pub) * 2];
+    char *end;
+
+    end = GNUNET_STRINGS_data_to_string (
+      &purse_pub,
+      sizeof (purse_pub),
+      pub_str,
+      sizeof (pub_str));
+    *end = '\0';
+    GNUNET_snprintf (arg_str,
+                     sizeof (arg_str),
+                     "/purses/%s/create",
+                     pub_str);
+  }
+  pch = GNUNET_new (struct TALER_EXCHANGE_PurseCreateDepositHandle);
+  pch->exchange = exchange;
+  pch->cb = cb;
+  pch->cb_cls = cb_cls;
+  GNUNET_CRYPTO_ecdhe_key_get_public (&contract_priv->ecdhe_priv,
+                                      &contract_pub.ecdhe_pub);
+  GNUNET_CRYPTO_eddsa_key_get_public (&merge_priv->eddsa_priv,
+                                      &merge_pub.eddsa_pub);
+  pch->url = TEAH_path_to_url (exchange,
+                               arg_str);
+  if (NULL == pch->url)
+  {
+    GNUNET_break (0);
+    GNUNET_free (pch);
+    return NULL;
+  }
+  deposit_arr = json_array ();
+  GNUNET_assert (NULL != deposit_arr);
+  url = TEAH_path_to_url (exchange,
+                          "/");
+  for (unsigned int i = 0; i<num_deposits; i++)
+  {
+    const struct TALER_EXCHANGE_PurseDeposit *deposit = &deposits[i];
+    json_t *jdeposit;
+    struct TALER_CoinSpendSignatureP coin_sig;
+#if FIXME_OEC
+    struct TALER_AgeCommitmentHash agh;
+    struct TALER_AgeCommitmentHash *aghp = NULL;
+    struct TALER_AgeAttestation attest;
+
+    TALER_age_commitment_hash (&deposit->age_commitment,
+                               &agh);
+    aghp = &agh;
+    if (GNUNET_OK !=
+        TALER_age_commitment_attest (&deposit->age_proof,
+                                     min_age,
+                                     &attest))
+    {
+      GNUNET_break (0);
+      json_decref (deposit_arr);
+      GNUNET_free (url);
+      GNUNET_free (pch);
+      return NULL;
+    }
+#endif
+    TALER_wallet_purse_deposit_sign (
+      url,
+      &purse_pub,
+      &deposit->amount,
+      &deposit->coin_priv,
+      &coin_sig);
+    jdeposit = GNUNET_JSON_PACK (
+#if FIXME_OEC
+      GNUNET_JSON_pack_allow_null (
+        GNUNET_JSON_pack_data_auto ("h_age_commitment",
+                                    aghp)),
+      GNUNET_JSON_pack_allow_null (
+        GNUNET_JSON_pack_data_auto ("age_attestation",
+                                    &attest)),
+#endif
+      TALER_JSON_pack_amount ("amount",
+                              &deposit->amount),
+      GNUNET_JSON_pack_data_auto ("denom_pub_hash",
+                                  &deposit->h_denom_pub),
+      TALER_JSON_pack_denom_sig ("ub_sig",
+                                 &deposit->denom_sig),
+      GNUNET_JSON_pack_data_auto ("coin_sig",
+                                  &coin_sig));
+    GNUNET_assert (0 ==
+                   json_array_append_new (deposit_arr,
+                                          jdeposit));
+  }
+  GNUNET_free (url);
+  {
+    void *econtract;
+    size_t econtract_size;
+
+    TALER_CRYPTO_contract_encrypt_for_merge (&purse_pub,
+                                             contract_priv,
+                                             merge_priv,
+                                             contract_terms,
+                                             &econtract,
+                                             &econtract_size);
+    create_obj = GNUNET_JSON_PACK (
+      TALER_JSON_pack_amount ("amount",
+                              &purse_value_after_fees),
+      GNUNET_JSON_pack_uint64 ("min_age",
+                               min_age),
+      GNUNET_JSON_pack_data_varsize ("econtract",
+                                     econtract,
+                                     econtract_size),
+      GNUNET_JSON_pack_data_auto ("contract_pub",
+                                  &contract_pub),
+      GNUNET_JSON_pack_data_auto ("merge_pub",
+                                  &merge_pub),
+      GNUNET_JSON_pack_data_auto ("h_contract_terms",
+                                  &h_contract_terms),
+      GNUNET_JSON_pack_array_steal ("deposits",
+                                    deposit_arr));
+    GNUNET_free (econtract);
+  }
+  GNUNET_assert (NULL != create_obj);
+  eh = TALER_EXCHANGE_curl_easy_get_ (pch->url);
+  if ( (NULL == eh) ||
+       (GNUNET_OK !=
+        TALER_curl_easy_post (&pch->ctx,
+                              eh,
+                              create_obj)) )
+  {
+    GNUNET_break (0);
+    if (NULL != eh)
+      curl_easy_cleanup (eh);
+    json_decref (create_obj);
+    GNUNET_free (pch->url);
+    GNUNET_free (pch);
+    return NULL;
+  }
+  json_decref (create_obj);
+  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+              "URL for purse create with deposit: `%s'\n",
+              pch->url);
+  ctx = TEAH_handle_to_context (exchange);
+  pch->job = GNUNET_CURL_job_add2 (ctx,
+                                   eh,
+                                   pch->ctx.headers,
+                                   &handle_purse_create_deposit_finished,
+                                   pch);
+  return pch;
+}
+
+
+void
+TALER_EXCHANGE_purse_create_with_deposit_cancel (
+  struct TALER_EXCHANGE_PurseCreateDepositHandle *pch)
+{
+  if (NULL != pch->job)
+  {
+    GNUNET_CURL_job_cancel (pch->job);
+    pch->job = NULL;
+  }
+  GNUNET_free (pch->url);
+  TALER_curl_easy_post_finished (&pch->ctx);
+  GNUNET_free (pch);
+}
+
+
+/* end of exchange_api_purse_create_with_deposit.c */