1 files changed, 291 insertions, 0 deletions

diff --git a/src/service/dht/gnunet-service-dht_datacache.c b/src/service/dht/gnunet-service-dht_datacache.c
new file mode 100644
index 000000000..dcb6308a9
--- /dev/null
+++ b/src/service/dht/gnunet-service-dht_datacache.c
@@ -0,0 +1,291 @@
+/*
+     This file is part of GNUnet.
+     Copyright (C) 2009, 2010, 2011, 2015, 2017, 2022 GNUnet e.V.
+
+     GNUnet 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 Foundation, either version 3 of the License,
+     or (at your option) any later version.
+
+     GNUnet 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
+     Affero General Public License for more details.
+
+     You should have received a copy of the GNU Affero General Public License
+     along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+     SPDX-License-Identifier: AGPL3.0-or-later
+ */
+/**
+ * @file dht/gnunet-service-dht_datacache.c
+ * @brief GNUnet DHT service's datacache integration
+ * @author Christian Grothoff
+ * @author Nathan Evans
+ */
+#include "platform.h"
+#include "gnunet_datacache_lib.h"
+#include "gnunet-service-dht_datacache.h"
+#include "gnunet-service-dht_neighbours.h"
+#include "gnunet-service-dht_routing.h"
+#include "gnunet-service-dht.h"
+
+#define LOG(kind, ...) GNUNET_log_from (kind, "dht-dhtcache", __VA_ARGS__)
+
+/**
+ * How many "closest" results to we return for migration when
+ * asked (at most)?
+ */
+#define NUM_CLOSEST 4
+
+
+/**
+ * Handle to the datacache service (for inserting/retrieving data)
+ */
+static struct GNUNET_DATACACHE_Handle *datacache;
+
+
+void
+GDS_DATACACHE_handle_put (const struct GNUNET_DATACACHE_Block *bd)
+{
+  struct GNUNET_HashCode xor;
+  enum GNUNET_GenericReturnValue r;
+
+  if (NULL == datacache)
+  {
+    GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
+                "PUT request received, but have no datacache!\n");
+    return;
+  }
+  if (bd->data_size >= GNUNET_MAX_MESSAGE_SIZE)
+  {
+    GNUNET_break (0);
+    return;
+  }
+  /* Put size is actual data size plus struct overhead plus path length (if any) */
+  GNUNET_STATISTICS_update (GDS_stats,
+                            "# ITEMS stored in datacache",
+                            1,
+                            GNUNET_NO);
+  GNUNET_CRYPTO_hash_xor (&bd->key,
+                          &GDS_my_identity_hash,
+                          &xor);
+  r = GNUNET_DATACACHE_put (datacache,
+                            GNUNET_CRYPTO_hash_count_leading_zeros (&xor),
+                            bd);
+  LOG (GNUNET_ERROR_TYPE_DEBUG,
+       "DATACACHE PUT for key %s [%lu] completed (%d) after %u hops\n",
+       GNUNET_h2s (&bd->key),
+       (unsigned long) bd->data_size,
+       r,
+       bd->put_path_length);
+}
+
+
+/**
+ * Context containing information about a GET request.
+ */
+struct GetRequestContext
+{
+  /**
+   * extended query (see gnunet_block_lib.h).
+   */
+  const void *xquery;
+
+  /**
+   * The key this request was about
+   */
+  struct GNUNET_HashCode key;
+
+  /**
+   * Block group to use to evaluate replies (updated)
+   */
+  struct GNUNET_BLOCK_Group *bg;
+
+  /**
+   * Function to call on results.
+   */
+  GDS_DATACACHE_GetCallback gc;
+
+  /**
+   * Closure for @e gc.
+   */
+  void *gc_cls;
+
+  /**
+   * Number of bytes in xquery.
+   */
+  size_t xquery_size;
+
+  /**
+   * Return value to give back.
+   */
+  enum GNUNET_BLOCK_ReplyEvaluationResult eval;
+};
+
+
+/**
+ * Iterator for local get request results,
+ *
+ * @param cls closure for iterator, a `struct GetRequestContext`
+ * @param bd block data
+ * @return #GNUNET_OK to continue iteration, anything else
+ * to stop iteration.
+ */
+static enum GNUNET_GenericReturnValue
+datacache_get_iterator (void *cls,
+                        const struct GNUNET_DATACACHE_Block *bd)
+{
+  struct GetRequestContext *ctx = cls;
+  enum GNUNET_BLOCK_ReplyEvaluationResult eval;
+
+  if (GNUNET_TIME_absolute_is_past (bd->expiration_time))
+  {
+    GNUNET_break (0);  /* why does datacache return expired values? */
+    return GNUNET_OK;   /* skip expired record */
+  }
+  eval
+    = GNUNET_BLOCK_check_reply (GDS_block_context,
+                                bd->type,
+                                ctx->bg,
+                                &bd->key,
+                                ctx->xquery,
+                                ctx->xquery_size,
+                                bd->data,
+                                bd->data_size);
+  LOG (GNUNET_ERROR_TYPE_DEBUG,
+       "Evaluated reply for query %s in datacache, result is %d\n",
+       GNUNET_h2s (&bd->key),
+       (int) eval);
+  ctx->eval = eval;
+  switch (eval)
+  {
+  case GNUNET_BLOCK_REPLY_OK_MORE:
+  case GNUNET_BLOCK_REPLY_OK_LAST:
+  case GNUNET_BLOCK_REPLY_TYPE_NOT_SUPPORTED:
+    /* forward to initiator */
+    GNUNET_STATISTICS_update (GDS_stats,
+                              "# Good RESULTS found in datacache",
+                              1,
+                              GNUNET_NO);
+    ctx->gc (ctx->gc_cls,
+             bd);
+    break;
+  case GNUNET_BLOCK_REPLY_OK_DUPLICATE:
+    GNUNET_STATISTICS_update (GDS_stats,
+                              "# Duplicate RESULTS found in datacache",
+                              1,
+                              GNUNET_NO);
+    break;
+  case GNUNET_BLOCK_REPLY_IRRELEVANT:
+    GNUNET_STATISTICS_update (GDS_stats,
+                              "# Irrelevant RESULTS found in datacache",
+                              1,
+                              GNUNET_NO);
+    break;
+  }
+  return (eval == GNUNET_BLOCK_REPLY_OK_LAST) ? GNUNET_NO : GNUNET_OK;
+}
+
+
+enum GNUNET_BLOCK_ReplyEvaluationResult
+GDS_DATACACHE_handle_get (const struct GNUNET_HashCode *key,
+                          enum GNUNET_BLOCK_Type type,
+                          const void *xquery,
+                          size_t xquery_size,
+                          struct GNUNET_BLOCK_Group *bg,
+                          GDS_DATACACHE_GetCallback gc,
+                          void *gc_cls)
+{
+  struct GetRequestContext ctx = {
+    .eval = GNUNET_BLOCK_REPLY_TYPE_NOT_SUPPORTED,
+    .key = *key,
+    .xquery = xquery,
+    .xquery_size = xquery_size,
+    .bg = bg,
+    .gc = gc,
+    .gc_cls = gc_cls
+  };
+  unsigned int r;
+
+  if (NULL == datacache)
+    return GNUNET_BLOCK_REPLY_TYPE_NOT_SUPPORTED;
+  GNUNET_STATISTICS_update (GDS_stats,
+                            "# GET requests given to datacache",
+                            1,
+                            GNUNET_NO);
+  r = GNUNET_DATACACHE_get (datacache,
+                            key,
+                            type,
+                            &datacache_get_iterator,
+                            &ctx);
+  LOG (GNUNET_ERROR_TYPE_DEBUG,
+       "DATACACHE GET for key %s completed (%d). %u results found.\n",
+       GNUNET_h2s (key),
+       ctx.eval,
+       r);
+  return ctx.eval;
+}
+
+
+enum GNUNET_BLOCK_ReplyEvaluationResult
+GDS_DATACACHE_get_closest (const struct GNUNET_HashCode *key,
+                           enum GNUNET_BLOCK_Type type,
+                           const void *xquery,
+                           size_t xquery_size,
+                           struct GNUNET_BLOCK_Group *bg,
+                           GDS_DATACACHE_GetCallback cb,
+                           void *cb_cls)
+{
+  struct GetRequestContext ctx = {
+    .eval = GNUNET_BLOCK_REPLY_TYPE_NOT_SUPPORTED,
+    .key = *key,
+    .xquery = xquery,
+    .xquery_size = xquery_size,
+    .bg = bg,
+    .gc = cb,
+    .gc_cls = cb_cls
+  };
+  unsigned int r;
+
+  if (NULL == datacache)
+    return GNUNET_BLOCK_REPLY_TYPE_NOT_SUPPORTED;
+  GNUNET_STATISTICS_update (GDS_stats,
+                            "# GET closest requests given to datacache",
+                            1,
+                            GNUNET_NO);
+  r = GNUNET_DATACACHE_get_closest (datacache,
+                                    key,
+                                    type,
+                                    NUM_CLOSEST,
+                                    &datacache_get_iterator,
+                                    &ctx);
+  LOG (GNUNET_ERROR_TYPE_DEBUG,
+       "DATACACHE approximate GET for key %s completed (%d). %u results found.\n",
+       GNUNET_h2s (key),
+       ctx.eval,
+       r);
+  return ctx.eval;
+}
+
+
+void
+GDS_DATACACHE_init ()
+{
+  datacache = GNUNET_DATACACHE_create (GDS_cfg,
+                                       "dhtcache");
+}
+
+
+void
+GDS_DATACACHE_done ()
+{
+  if (NULL != datacache)
+  {
+    GNUNET_DATACACHE_destroy (datacache);
+    datacache = NULL;
+  }
+}
+
+
+/* end of gnunet-service-dht_datacache.c */