1 files changed, 169 insertions, 0 deletions

diff --git a/src/rps/gnunet-service-rps_sampler_elem.c b/src/rps/gnunet-service-rps_sampler_elem.c
new file mode 100644
index 000000000..16b9cb39e
--- /dev/null
+++ b/src/rps/gnunet-service-rps_sampler_elem.c
@@ -0,0 +1,169 @@
+/*
+     This file is part of GNUnet.
+     Copyright (C)
+
+     GNUnet 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.
+
+     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
+     General Public License for more details.
+
+     You should have received a copy of the GNU General Public License
+     along with GNUnet; see the file COPYING.  If not, write to the
+     Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+     Boston, MA 02110-1301, USA.
+*/
+
+/**
+ * @file rps/gnunet-service-rps_sampler.c
+ * @brief sampler implementation
+ * @author Julius Bünger
+ */
+#include "platform.h"
+#include "gnunet_util_lib.h"
+
+#include "gnunet-service-rps_sampler_elem.h"
+
+#include <inttypes.h>
+
+#include "rps-test_util.h"
+
+#define LOG(kind, ...) GNUNET_log_from(kind,"rps-sampler_elem",__VA_ARGS__)
+
+
+// TODO check for overflows
+
+/***********************************************************************
+ * WARNING: This section needs to be reviewed regarding the use of
+ * functions providing (pseudo)randomness!
+***********************************************************************/
+
+// TODO care about invalid input of the caller (size 0 or less...)
+
+
+/**
+ * Reinitialise a previously initialised sampler element.
+ *
+ * @param sampler pointer to the memory that keeps the value.
+ */
+void
+RPS_sampler_elem_reinit (struct RPS_SamplerElement *sampler_el)
+{
+  sampler_el->is_empty = EMPTY;
+
+  // I guess I don't need to call GNUNET_CRYPTO_hmac_derive_key()...
+  GNUNET_CRYPTO_random_block(GNUNET_CRYPTO_QUALITY_STRONG,
+                             &(sampler_el->auth_key.key),
+                             GNUNET_CRYPTO_HASH_LENGTH);
+
+  #ifdef TO_FILE
+  /* Create a file(-name) to store internals to */
+  char *name_buf;
+  name_buf = auth_key_to_string (sampler_el->auth_key);
+
+  sampler_el->file_name = create_file (name_buf);
+  GNUNET_free (name_buf);
+  #endif /* TO_FILE */
+
+  sampler_el->last_client_request = GNUNET_TIME_UNIT_FOREVER_ABS;
+
+  sampler_el->birth = GNUNET_TIME_absolute_get ();
+  sampler_el->num_peers = 0;
+  sampler_el->num_change = 0;
+}
+
+
+/**
+ * (Re)Initialise given Sampler with random min-wise independent function.
+ *
+ * In this implementation this means choosing an auth_key for later use in
+ * a hmac at random.
+ *
+ * @return a newly created RPS_SamplerElement which currently holds no id.
+ */
+struct RPS_SamplerElement *
+RPS_sampler_elem_create (void)
+{
+  struct RPS_SamplerElement *s;
+
+  s = GNUNET_new (struct RPS_SamplerElement);
+
+  RPS_sampler_elem_reinit (s);
+
+  return s;
+}
+
+
+/**
+ * Input an PeerID into the given sampler element.
+ *
+ * @param sampler the sampler the @a s_elem belongs to.
+ *                Needed to know the
+ */
+void
+RPS_sampler_elem_next (struct RPS_SamplerElement *s_elem,
+                       const struct GNUNET_PeerIdentity *other)
+{
+  struct GNUNET_HashCode other_hash;
+
+  s_elem->num_peers++;
+
+  to_file (s_elem->file_name,
+           "Got id %s",
+           GNUNET_i2s_full (other));
+
+  if (0 == GNUNET_CRYPTO_cmp_peer_identity (other, &(s_elem->peer_id)))
+  {
+    LOG (GNUNET_ERROR_TYPE_DEBUG, "         Got PeerID %s\n",
+        GNUNET_i2s (other));
+    LOG (GNUNET_ERROR_TYPE_DEBUG, "Have already PeerID %s\n",
+        GNUNET_i2s (&(s_elem->peer_id)));
+  }
+  else
+  {
+    GNUNET_CRYPTO_hmac(&s_elem->auth_key,
+        other,
+        sizeof(struct GNUNET_PeerIdentity),
+        &other_hash);
+
+    if (EMPTY == s_elem->is_empty)
+    {
+      LOG (GNUNET_ERROR_TYPE_DEBUG,
+           "Got PeerID %s; Simply accepting (was empty previously).\n",
+           GNUNET_i2s(other));
+      s_elem->peer_id = *other;
+      s_elem->peer_id_hash = other_hash;
+
+      s_elem->num_change++;
+    }
+    else if (0 > GNUNET_CRYPTO_hash_cmp (&other_hash, &s_elem->peer_id_hash))
+    {
+      LOG (GNUNET_ERROR_TYPE_DEBUG, "           Got PeerID %s\n",
+          GNUNET_i2s (other));
+      LOG (GNUNET_ERROR_TYPE_DEBUG, "Discarding old PeerID %s\n",
+          GNUNET_i2s (&s_elem->peer_id));
+      s_elem->peer_id = *other;
+      s_elem->peer_id_hash = other_hash;
+
+      s_elem->num_change++;
+    }
+    else
+    {
+      LOG (GNUNET_ERROR_TYPE_DEBUG, "        Got PeerID %s\n",
+          GNUNET_i2s (other));
+      LOG (GNUNET_ERROR_TYPE_DEBUG, "Keeping old PeerID %s\n",
+          GNUNET_i2s (&s_elem->peer_id));
+    }
+  }
+  s_elem->is_empty = NOT_EMPTY;
+
+  to_file (s_elem->file_name,
+           "Now holding %s",
+           GNUNET_i2s_full (&s_elem->peer_id));
+}
+
+/* end of gnunet-service-rps.c */