push back
[oweals/gnunet.git] / src / nse / gnunet-service-nse.c
index 6c4466bc7f9a554db9ec61b1eeef6b5481af30b2..3d980ca26ae04eed46f6671d496b9c8a54c1ea1c 100644 (file)
 /*
-     This file is part of GNUnet.
-     (C) 2009, 2010, 2011 Christian Grothoff (and other contributing authors)
-
-     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., 59 Temple Place - Suite 330,
-     Boston, MA 02111-1307, USA.
-*/
+  This file is part of GNUnet.
+  (C) 2009, 2010, 2011 Christian Grothoff (and other contributing authors)
+  
+  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., 59 Temple Place - Suite 330,
+  Boston, MA 02111-1307, USA.
+ */
 
 /**
  * @file nse/gnunet-service-nse.c
  * @brief network size estimation service
  * @author Nathan Evans
+ * @author Christian Grothoff
  *
  * The purpose of this service is to estimate the size of the network.
  * Given a specified interval, each peer hashes the most recent
- * timestamp which is evenly divisible by that interval.  This hash
- * is compared in distance to the peer identity to choose an offset.
- * The closer the peer identity to the hashed timestamp, the earlier
- * the peer sends out a "nearest peer" message.  The closest peer's
+ * timestamp which is evenly divisible by that interval.  This hash is
+ * compared in distance to the peer identity to choose an offset.  The
+ * closer the peer identity to the hashed timestamp, the earlier the
+ * peer sends out a "nearest peer" message.  The closest peer's
  * message should thus be received before any others, which stops
  * those peer from sending their messages at a later duration.  So
- * every peer should receive the same nearest peer message, and
- * from this can calculate the expected number of peers in the
- * network.
- *
+ * every peer should receive the same nearest peer message, and from
+ * this can calculate the expected number of peers in the network.
  */
 #include "platform.h"
-#include "gnunet_client_lib.h"
+#include "gnunet_util_lib.h"
 #include "gnunet_constants.h"
-#include "gnunet_container_lib.h"
 #include "gnunet_protocols.h"
-#include "gnunet_service_lib.h"
-#include "gnunet_server_lib.h"
+#include "gnunet_signatures.h"
+#include "gnunet_statistics_service.h"
 #include "gnunet_core_service.h"
-#include "gnunet_time_lib.h"
 #include "gnunet_nse_service.h"
 #include "nse.h"
 
-#define DEFAULT_HISTORY_SIZE 10
+/**
+ * Send messages on connect.
+ */
+#define SEND_ON_CONNECT GNUNET_YES
 
-#define DEFAULT_CORE_QUEUE_SIZE 32
+/**
+ * Should we generate a histogram with the time stamps of when we received
+ * NSE messages to disk? (for performance evaluation only, not useful in
+ * production)
+ */
+#define ENABLE_HISTOGRAM GNUNET_YES
 
-#define MILLISECONDS_PER_DAY 86400000
+/**
+ * Over how many values do we calculate the weighted average?
+ */
+#define HISTORY_SIZE 8
 
 /**
- * Entry in the list of clients which
- * should be notified upon a new network
- * size estimate calculation.
+ * Size of the queue to core.
  */
-struct ClientListEntry
+#define CORE_QUEUE_SIZE 2
+
+/**
+ * Message priority to use.
+ */
+#define NSE_PRIORITY 5
+
+/**
+ * Amount of work required (W-bit collisions) for NSE proofs, in collision-bits.
+ */
+static unsigned long long nse_work_required;
+
+/**
+ * Interval for sending network size estimation flood requests.
+ */
+static struct GNUNET_TIME_Relative gnunet_nse_interval;
+
+/**
+ * Interval between proof find runs.
+ */
+static struct GNUNET_TIME_Relative proof_find_delay;
+
+
+#if ENABLE_HISTOGRAM
+static struct GNUNET_BIO_WriteHandle *wh;
+#endif
+
+
+/**
+ * Per-peer information.
+ */
+struct NSEPeerEntry
 {
+
+  /**
+   * Pending message for this peer.
+   */
+  struct GNUNET_MessageHeader *pending_message;
+
+  /**
+   * Core handle for sending messages to this peer.
+   */
+  struct GNUNET_CORE_TransmitHandle *th;
+
   /**
-   *  Pointer to previous entry
+   * What is the identity of the peer?
    */
-  struct ClientListEntry *prev;
+  struct GNUNET_PeerIdentity id;
 
   /**
-   *  Pointer to next entry
+   * Task scheduled to send message to this peer.
    */
-  struct ClientListEntry *next;
+  GNUNET_SCHEDULER_TaskIdentifier transmit_task;
 
   /**
-   * Client to notify.
+   * Did we receive or send a message about the previous round
+   * to this peer yet?   GNUNET_YES if the previous round has
+   * been taken care of.
    */
-  struct GNUNET_SERVER_Client *client;
+  int previous_round;
 };
 
+
+/**
+ * Network size estimate reply; sent when "this"
+ * peer's timer has run out before receiving a
+ * valid reply from another peer.
+ */
+struct GNUNET_NSE_FloodMessage
+{
+  /**
+   * Type: GNUNET_MESSAGE_TYPE_NSE_P2P_FLOOD
+   */
+  struct GNUNET_MessageHeader header;
+
+  /**
+   * Number of hops this message has taken so far.
+   */
+  uint32_t hop_count;
+
+  /**
+   * Purpose.
+   */
+  struct GNUNET_CRYPTO_RsaSignaturePurpose purpose;
+
+  /**
+   * The current timestamp value (which all
+   * peers should agree on).
+   */
+  struct GNUNET_TIME_AbsoluteNBO timestamp;
+
+  /**
+   * Number of matching bits between the hash
+   * of timestamp and the initiator's public
+   * key.
+   */
+  uint32_t matching_bits;
+
+  /**
+   * Public key of the originator.
+   */
+  struct GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded pkey;
+
+  /**
+   * Proof of work, causing leading zeros when hashed with pkey.
+   */
+  uint64_t proof_of_work;
+
+  /**
+   * Signature (over range specified in purpose).
+   */
+  struct GNUNET_CRYPTO_RsaSignature signature;
+};
+
+
 /**
  * Handle to our current configuration.
  */
 static const struct GNUNET_CONFIGURATION_Handle *cfg;
 
+/**
+ * Handle to the statistics service.
+ */
+static struct GNUNET_STATISTICS_Handle *stats;
+
 /**
  * Handle to the core service.
  */
-struct GNUNET_CORE_Handle *coreAPI;
+static struct GNUNET_CORE_Handle *coreAPI;
 
 /**
- * Copy of this peer's identity.
+ * Map of all connected peers.
  */
-static struct GNUNET_PeerIdentity my_identity;
+static struct GNUNET_CONTAINER_MultiHashMap *peers;
 
 /**
- * Head of global list of clients.
+ * The current network size estimate.  Number of bits matching on
+ * average thus far. 
  */
-static struct ClientListEntry *cle_head;
+static double current_size_estimate;
 
 /**
- * Tail of global list of clients.
+ * The standard deviation of the last HISTORY_SIZE network
+ * size estimates.
  */
-static struct ClientListEntry *cle_tail;
+static double current_std_dev = NAN;
 
 /**
- * The current network size estimate.
+ * Current hop counter estimate (estimate for network diameter).
  */
-static double current_size_estimate;
+static uint32_t hop_count_max;
 
 /**
- * The standard deviation of the last
- * DEFAULT_HISTORY_SIZE network size estimates.
+ * Message for the next round, if we got any.
  */
-static double current_std_dev;
+static struct GNUNET_NSE_FloodMessage next_message;
 
 /**
- * Array of the last DEFAULT_HISTORY_SIZE
- * network size estimates.
+ * Array of recent size estimate messages.
  */
-//static double *size_estimates[DEFAULT_HISTORY_SIZE];
+static struct GNUNET_NSE_FloodMessage size_estimate_messages[HISTORY_SIZE];
 
 /**
- * Task scheduled to send flood message.
+ * Index of most recent estimate.
+ */
+static unsigned int estimate_index;
+
+/**
+ * Number of valid entries in the history.
+ */
+static unsigned int estimate_count;
+
+/**
+ * Task scheduled to update our flood message for the next round.
  */
 static GNUNET_SCHEDULER_TaskIdentifier flood_task;
 
 /**
- * Notification context, simplifies client broadcasts.
+ * Task scheduled to compute our proof.
  */
-static struct GNUNET_SERVER_NotificationContext *nc;
+static GNUNET_SCHEDULER_TaskIdentifier proof_task;
 
 /**
- * The previous major time.
+ * Notification context, simplifies client broadcasts.
  */
-struct GNUNET_TIME_Absolute previous_timestamp;
+static struct GNUNET_SERVER_NotificationContext *nc;
 
 /**
  * The next major time.
@@ -140,14 +258,88 @@ struct GNUNET_TIME_Absolute previous_timestamp;
 static struct GNUNET_TIME_Absolute next_timestamp;
 
 /**
- * Base increment of time to add to send time.
+ * The current major time.
+ */
+static struct GNUNET_TIME_Absolute current_timestamp;
+
+/**
+ * The public key of this peer.
+ */
+static struct GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded my_public_key;
+
+/**
+ * The private key of this peer.
+ */
+static struct GNUNET_CRYPTO_RsaPrivateKey *my_private_key;
+
+/**
+ * The peer identity of this peer.
  */
-static struct GNUNET_TIME_Relative increment;
+static struct GNUNET_PeerIdentity my_identity;
 
 /**
- * The current network size estimate message.
+ * Proof of work for this peer.
  */
-static struct GNUNET_NSE_ClientMessage current_estimate_message;
+static uint64_t my_proof;
+
+
+/**
+ * Initialize a message to clients with the current network
+ * size estimate.
+ *
+ * @param em message to fill in
+ */
+static void
+setup_estimate_message (struct GNUNET_NSE_ClientMessage *em)
+{
+  unsigned int i;
+  double mean;
+  double sum;
+  double std_dev;
+  double variance;
+  double val;
+  double weight;
+  double sumweight;
+  double q;
+  double r;
+  double temp;
+
+  /* Weighted incremental algorithm for stddev according to West (1979) */
+  mean = 0.0;
+  sum = 0.0;
+  sumweight = 0.0;
+  for (i = 0; i < estimate_count; i++)
+    {
+      val = htonl (size_estimate_messages[(estimate_index - i + HISTORY_SIZE)
+          % HISTORY_SIZE].matching_bits);
+      weight = 1; /* was: estimate_count + 1 - i; */
+
+      temp = weight + sumweight;
+      q = val - mean;
+      r = q * weight / temp;
+      sum += sumweight * q * r;
+      mean += r;
+      sumweight = temp;
+    }
+  variance = sum / (sumweight - 1.0);
+  GNUNET_assert (variance >= 0);
+  std_dev = sqrt (variance);
+  current_std_dev = std_dev;
+  current_size_estimate = mean;
+
+  em->header.size
+    = htons (sizeof(struct GNUNET_NSE_ClientMessage));
+  em->header.type
+    = htons (GNUNET_MESSAGE_TYPE_NSE_ESTIMATE);
+  em->reserved = htonl (0);
+  em->timestamp = GNUNET_TIME_absolute_hton(GNUNET_TIME_absolute_get());
+  em->size_estimate = mean - 1.0/3.0;
+  em->std_deviation = std_dev;
+  GNUNET_STATISTICS_set (stats, 
+                        "# nodes in the network (estimate)",
+                        (uint64_t) pow (2, mean - 1.0/3.0), GNUNET_NO);
+}
+
 
 /**
  * Handler for START message from client, triggers an
@@ -160,154 +352,883 @@ static struct GNUNET_NSE_ClientMessage current_estimate_message;
  * @param message the message received
  */
 static void
-handle_start_message (void *cls,
-                      struct GNUNET_SERVER_Client *client,
-                      const struct GNUNET_MessageHeader *message)
+handle_start_message(void *cls, struct GNUNET_SERVER_Client *client,
+                     const struct GNUNET_MessageHeader *message)
 {
-  if ((ntohs (message->size) != sizeof(struct GNUNET_MessageHeader))
-      || (ntohs (message->type) != GNUNET_MESSAGE_TYPE_NSE_START))
-    return;
+  struct GNUNET_NSE_ClientMessage em;
 
 #if DEBUG_NSE
-  GNUNET_log_from (GNUNET_ERROR_TYPE_DEBUG, "NSE", "Received START message from client\n");
+  GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, 
+            "Received START message from client\n");
 #endif
   GNUNET_SERVER_notification_context_add (nc, client);
-  GNUNET_SERVER_notification_context_unicast (nc, client,
-                                              &current_estimate_message.header,
-                                              GNUNET_NO);
-  GNUNET_SERVER_receive_done(client, GNUNET_OK);
+  setup_estimate_message (&em);
+  GNUNET_SERVER_notification_context_unicast (nc, client, &em.header, GNUNET_YES);
+  GNUNET_SERVER_receive_done (client, GNUNET_OK);
 }
 
+
 /**
- * Core handler for size estimate flooding messages.
+ * How long should we delay a message to go the given number of
+ * matching bits?
  *
- * @param cls closure
- * @param message message
- * @param peer peer identity this notification is about
- * @param atsi performance data
+ * @param matching_bits number of matching bits to consider
+ */
+static double
+get_matching_bits_delay (uint32_t matching_bits)
+{
+  /* Calculated as: S + f/2 - (f / pi) * (atan(x - p'))*/  
+  // S is next_timestamp (ignored in return value)
+  // f is frequency (gnunet_nse_interval)
+  // x is matching_bits
+  // p' is current_size_estimate
+  return ((double) gnunet_nse_interval.rel_value / (double) 2.0)
+    - ((gnunet_nse_interval.rel_value / M_PI) * atan (matching_bits - current_size_estimate));
+}
+
+
+/**
+ * What delay randomization should we apply for a given number of matching bits?
  *
+ * @param matching_bits number of matching bits
+ * @return random delay to apply 
  */
-static int
-handle_p2p_size_estimate (void *cls,
-                              const struct GNUNET_PeerIdentity *peer,
-                              const struct GNUNET_MessageHeader *message,
-                              const struct GNUNET_TRANSPORT_ATS_Information
-                              *atsi)
+static struct GNUNET_TIME_Relative 
+get_delay_randomization (uint32_t matching_bits)
 {
+  struct GNUNET_TIME_Relative ret;
 
-  return GNUNET_OK;
+  if (matching_bits == 0)
+    return GNUNET_TIME_UNIT_ZERO;
+  ret.rel_value = GNUNET_CRYPTO_random_u32 (GNUNET_CRYPTO_QUALITY_WEAK,
+                                           (uint32_t) (get_matching_bits_delay (matching_bits - 1) / (double) (hop_count_max + 1)));
+  return ret;
+}
+
+
+/**
+ * Get the number of matching bits that the given timestamp has to the given peer ID.
+ *
+ * @param timestamp time to generate key
+ * @param id peer identity to compare with
+ * @return number of matching bits
+ */
+static uint32_t
+get_matching_bits (struct GNUNET_TIME_Absolute timestamp,
+                  const struct GNUNET_PeerIdentity *id)
+{
+  GNUNET_HashCode timestamp_hash;
+
+  GNUNET_CRYPTO_hash (&timestamp.abs_value,
+                      sizeof(timestamp.abs_value), 
+                     &timestamp_hash);
+  return GNUNET_CRYPTO_hash_matching_bits (&timestamp_hash,
+                                          &id->hashPubKey);
+}
+
+
+/**
+ * Get the transmission delay that should be applied for a 
+ * particular round.
+ *
+ * @param round_offset -1 for the previous round (random delay between 0 and 50ms)
+ *                      0 for the current round (based on our proximity to time key)
+ * @return delay that should be applied
+ */
+static struct GNUNET_TIME_Relative
+get_transmit_delay (int round_offset)
+{
+  struct GNUNET_TIME_Relative ret;
+  struct GNUNET_TIME_Absolute tgt;
+  double dist_delay;
+  uint32_t matching_bits;
+
+  switch (round_offset)
+    {
+    case -1:
+      /* previous round is randomized between 0 and 50 ms */
+      ret.rel_value = GNUNET_CRYPTO_random_u64 (GNUNET_CRYPTO_QUALITY_WEAK,
+                                               50);
+#if DEBUG_NSE
+      GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, 
+                "Transmitting previous round behind schedule in %llu ms\n",
+                (unsigned long long) ret.rel_value);
+#endif
+      return ret;
+    case 0:
+      /* current round is based on best-known matching_bits */
+      matching_bits = ntohl (size_estimate_messages[estimate_index].matching_bits);
+      dist_delay = get_matching_bits_delay (matching_bits);
+      dist_delay += get_delay_randomization (matching_bits).rel_value;
+      ret.rel_value = (uint64_t) dist_delay;
+#if DEBUG_NSE
+      GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, 
+                "For round %llu, delay for %u matching bits is %llu ms\n",
+                (unsigned long long) current_timestamp.abs_value,
+                (unsigned int) matching_bits,
+                (unsigned long long) ret.rel_value);
+#endif
+      /* now consider round start time and add delay to it */
+      tgt = GNUNET_TIME_absolute_add (current_timestamp, ret);
+      return GNUNET_TIME_absolute_get_remaining (tgt);
+    }
+  GNUNET_break (0);
+  return GNUNET_TIME_UNIT_FOREVER_REL;
+}
+
+
+/**
+ * Task that triggers a NSE P2P transmission.
+ *
+ * @param cls the 'struct NSEPeerEntry'
+ * @param tc scheduler context
+ */
+static void
+transmit_task (void *cls,
+              const struct GNUNET_SCHEDULER_TaskContext *tc);
+
+
+/**
+ * Called when core is ready to send a message we asked for
+ * out to the destination.
+ *
+ * @param cls closure (NULL)
+ * @param size number of bytes available in buf
+ * @param buf where the callee should write the message
+ * @return number of bytes written to buf
+ */
+static size_t
+transmit_ready (void *cls, size_t size, void *buf)
+{
+  struct NSEPeerEntry *peer_entry = cls;
+  unsigned int idx;
+
+  peer_entry->th = NULL;
+  if (buf == NULL)
+    {
+      /* client disconnected */
+      return 0;
+    }
+  GNUNET_assert (size >= sizeof (struct GNUNET_NSE_FloodMessage));
+  idx = estimate_index;
+  if (peer_entry->previous_round == GNUNET_NO)
+    {
+      idx = (idx + HISTORY_SIZE - 1) % HISTORY_SIZE;
+      peer_entry->previous_round = GNUNET_YES;
+      peer_entry->transmit_task = GNUNET_SCHEDULER_add_delayed (get_transmit_delay (0),
+                                                               &transmit_task,
+                                                               peer_entry);
+    }
+  if ( (ntohl (size_estimate_messages[idx].hop_count) == 0) &&
+       (GNUNET_SCHEDULER_NO_TASK != proof_task) )
+    {
+      GNUNET_STATISTICS_update (stats, 
+                               "# flood messages not generated (no proof yet)", 
+                               1,
+                               GNUNET_NO);
+      return 0; 
+    }
+#if DEBUG_NSE
+  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, 
+             "In round %llu, sending to `%s' estimate with %u bits\n",
+             (unsigned long long) GNUNET_TIME_absolute_ntoh (size_estimate_messages[idx].timestamp).abs_value,
+             GNUNET_i2s (&peer_entry->id),
+             (unsigned int) ntohl (size_estimate_messages[idx].matching_bits));
+#endif
+  if (ntohl (size_estimate_messages[idx].hop_count) == 0) 
+    GNUNET_STATISTICS_update (stats, 
+                             "# flood messages started", 
+                             1,
+                             GNUNET_NO);
+  GNUNET_STATISTICS_update (stats, 
+                           "# flood messages transmitted", 
+                           1,
+                           GNUNET_NO);
+  memcpy (buf,
+         &size_estimate_messages[idx],
+         sizeof (struct GNUNET_NSE_FloodMessage));
+  GNUNET_STATISTICS_update (stats, 
+                           "# flood messages sent", 
+                           1, 
+                           GNUNET_NO);
+  return sizeof (struct GNUNET_NSE_FloodMessage);
+}
+
+
+/**
+ * Task that triggers a NSE P2P transmission.
+ *
+ * @param cls the 'struct NSEPeerEntry'
+ * @param tc scheduler context
+ */
+static void
+transmit_task (void *cls,
+              const struct GNUNET_SCHEDULER_TaskContext *tc)
+{
+  struct NSEPeerEntry *peer_entry = cls;
+  peer_entry->transmit_task = GNUNET_SCHEDULER_NO_TASK;
+  peer_entry->th
+    = GNUNET_CORE_notify_transmit_ready (coreAPI,
+                                        GNUNET_NO,
+                                        NSE_PRIORITY,
+                                        GNUNET_TIME_UNIT_FOREVER_REL,
+                                        &peer_entry->id,
+                                        sizeof (struct GNUNET_NSE_FloodMessage),
+                                        &transmit_ready, peer_entry);
 }
 
 
 /**
- * Send a flood message containing our peer's public key
- * and the hashed current timestamp.
+ * We've sent on our flood message or one that we received which was
+ * validated and closer than ours.  Update the global list of recent
+ * messages and the average.  Also re-broadcast the message to any
+ * clients.
  */
 static void
-send_flood_message (void *cls,
-                    const struct GNUNET_SCHEDULER_TaskContext * tc)
+update_network_size_estimate ()
 {
-  if ((tc->reason & GNUNET_SCHEDULER_REASON_SHUTDOWN) != 0)
-    return;
+  struct GNUNET_NSE_ClientMessage em;
+
+  setup_estimate_message (&em);
+  GNUNET_SERVER_notification_context_broadcast (nc,
+                                               &em.header,
+                                               GNUNET_YES);    
 }
 
+
 /**
- * A client disconnected. Remove it from the
- * global DLL of clients.
+ * Setup a flood message in our history array at the given
+ * slot offset for the given timestamp.
  *
- * @param cls closure, NULL
- * @param client identification of the client
+ * @param slot index to use
+ * @param ts timestamp to use
  */
 static void
-handle_client_disconnect (void *cls,
-                          struct GNUNET_SERVER_Client* client)
+setup_flood_message (unsigned int slot,
+                    struct GNUNET_TIME_Absolute ts)
 {
-  struct ClientListEntry *cle;
+  struct GNUNET_NSE_FloodMessage *fm;
+  uint32_t matching_bits;
+
+  matching_bits = get_matching_bits (ts, &my_identity);
+  fm = &size_estimate_messages[slot];
+  fm->header.size = htons (sizeof(struct GNUNET_NSE_FloodMessage));
+  fm->header.type = htons (GNUNET_MESSAGE_TYPE_NSE_P2P_FLOOD);
+  fm->hop_count = htonl (0);
+  fm->purpose.purpose = htonl (GNUNET_SIGNATURE_PURPOSE_NSE_SEND);
+  fm->purpose.size = htonl (sizeof(struct GNUNET_NSE_FloodMessage)
+                           - sizeof (struct GNUNET_MessageHeader) 
+                           - sizeof (uint32_t)
+                           - sizeof (struct GNUNET_CRYPTO_RsaSignature));
+  fm->matching_bits = htonl (matching_bits);
+  fm->timestamp = GNUNET_TIME_absolute_hton (ts);
+  fm->pkey = my_public_key;
+  fm->proof_of_work = my_proof;
+  GNUNET_CRYPTO_rsa_sign (my_private_key, 
+                         &fm->purpose,
+                          &fm->signature);
+}
 
-  while (NULL != (cle = cle_head))
-    cle = cle->next;
 
-  if (cle != NULL)
+/**
+ * Schedule transmission for the given peer for the current round based
+ * on what we know about the desired delay.
+ *
+ * @param cls unused
+ * @param key hash of peer identity
+ * @param value the 'struct NSEPeerEntry'
+ * @return GNUNET_OK (continue to iterate)
+ */
+static int
+schedule_current_round (void *cls,
+                       const GNUNET_HashCode *key,
+                       void *value)
+{
+  struct NSEPeerEntry *peer_entry = value;
+  struct GNUNET_TIME_Relative delay;
+
+  if (peer_entry->th != NULL)
     {
-      GNUNET_SERVER_client_drop(cle->client);
-      GNUNET_CONTAINER_DLL_remove(cle_head,
-                                  cle_tail,
-                                  cle);
-      GNUNET_free(cle);
+      peer_entry->previous_round = GNUNET_NO;
+      return GNUNET_OK;
     }
-  if (coreAPI != NULL)
+  if (peer_entry->transmit_task != GNUNET_SCHEDULER_NO_TASK)
     {
-      GNUNET_CORE_disconnect(coreAPI);
-      coreAPI = NULL;
+      GNUNET_SCHEDULER_cancel (peer_entry->transmit_task);
+      peer_entry->previous_round = GNUNET_NO;
     }
+  delay = get_transmit_delay ((peer_entry->previous_round == GNUNET_NO) ? -1 : 0);
+  peer_entry->transmit_task = GNUNET_SCHEDULER_add_delayed (delay,
+                                                           &transmit_task,
+                                                           peer_entry);
+  return GNUNET_OK;
 }
 
+
 /**
- * Task run during shutdown.
+ * Update our flood message to be sent (and our timestamps).
  *
  * @param cls unused
- * @param tc unused
+ * @param tc context for this message
  */
 static void
-shutdown_task (void *cls,
-               const struct GNUNET_SCHEDULER_TaskContext *tc)
+update_flood_message(void *cls,
+                    const struct GNUNET_SCHEDULER_TaskContext *tc)
 {
-  struct ClientListEntry *cle;
+  struct GNUNET_TIME_Relative offset;
+  unsigned int i;
 
-  GNUNET_SERVER_notification_context_destroy (nc);
-  nc = NULL;
-  while (NULL != (cle = cle_head))
+  flood_task = GNUNET_SCHEDULER_NO_TASK;
+  offset = GNUNET_TIME_absolute_get_remaining (next_timestamp);
+  if (0 != offset.rel_value)
     {
-      GNUNET_SERVER_client_drop (cle->client);
-      GNUNET_CONTAINER_DLL_remove (cle_head,
-                                   cle_tail,
-                                   cle);
-      GNUNET_free (cle);
+      /* somehow run early, delay more */
+      flood_task
+       = GNUNET_SCHEDULER_add_delayed (offset,
+                                       &update_flood_message, 
+                                       NULL);
+      return;
     }
+  current_timestamp = next_timestamp;
+  next_timestamp = GNUNET_TIME_absolute_add (current_timestamp,
+                                            gnunet_nse_interval);
+  estimate_index = (estimate_index + 1) % HISTORY_SIZE;
+  if (estimate_count < HISTORY_SIZE)
+    estimate_count++;
+  if (next_timestamp.abs_value == 
+      GNUNET_TIME_absolute_ntoh (next_message.timestamp).abs_value)
+    {
+      /* we received a message for this round way early, use it! */
+      size_estimate_messages[estimate_index] = next_message;
+      size_estimate_messages[estimate_index].hop_count 
+       = htonl (1 + ntohl (next_message.hop_count));
+    }
+  else
+    setup_flood_message (estimate_index, current_timestamp);
+  next_message.matching_bits = htonl (0); /* reset for 'next' round */
+  hop_count_max = 0;
+  for (i = 0; i < HISTORY_SIZE; i++)
+    hop_count_max = GNUNET_MAX (ntohl (size_estimate_messages[i].hop_count),
+                               hop_count_max);
+  GNUNET_CONTAINER_multihashmap_iterate (peers,
+                                        &schedule_current_round,
+                                        NULL);
+  flood_task = GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_absolute_get_remaining (next_timestamp), 
+                                            &update_flood_message, NULL);
+}
 
-  if (coreAPI != NULL)
+
+/**
+ * Count the leading zeroes in hash.
+ *
+ * @param hash
+ * @return the number of leading zero bits.
+ */
+static unsigned int 
+count_leading_zeroes(const GNUNET_HashCode *hash)
+{
+  unsigned int hash_count;
+  
+  hash_count = 0;
+  while ((0 == GNUNET_CRYPTO_hash_get_bit(hash, hash_count)))
+    hash_count++;
+  return hash_count;
+}
+
+
+/**
+ * Check whether the given public key
+ * and integer are a valid proof of work.
+ *
+ * @param pkey the public key
+ * @param val the integer
+ *
+ * @return GNUNET_YES if valid, GNUNET_NO if not
+ */
+static int
+check_proof_of_work(const struct GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded *pkey,
+                   uint64_t val)
+{  
+  char buf[sizeof(struct GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded) + sizeof(val)];
+  GNUNET_HashCode result;
+  
+  memcpy (buf,
+         &val,
+         sizeof (val));
+  memcpy (&buf[sizeof(val)],
+         pkey, 
+         sizeof(struct GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded));
+  GNUNET_CRYPTO_hash (buf, sizeof (buf), &result);
+  return (count_leading_zeroes (&result) >= nse_work_required) ? GNUNET_YES : GNUNET_NO;
+}
+
+
+/**
+ * Write our current proof to disk.
+ */
+static void
+write_proof ()
+{
+  char *proof;
+
+  if (GNUNET_OK != 
+      GNUNET_CONFIGURATION_get_value_filename (cfg,
+                                              "NSE", "PROOFFILE",
+                                              &proof))
+    return;    
+  if (sizeof (my_proof) !=
+      GNUNET_DISK_fn_write (proof,
+                           &my_proof,
+                           sizeof (my_proof),
+                           GNUNET_DISK_PERM_USER_READ | GNUNET_DISK_PERM_USER_WRITE))
+    GNUNET_log_strerror_file (GNUNET_ERROR_TYPE_WARNING,
+                             "write",
+                             proof);   
+  GNUNET_free (proof);
+
+}
+
+
+/**
+ * Find our proof of work.
+ *
+ * @param cls closure (unused)
+ * @param tc task context
+ */
+static void
+find_proof (void *cls,
+           const struct GNUNET_SCHEDULER_TaskContext *tc)
+{
+#define ROUND_SIZE 10
+  uint64_t counter;
+  char buf[sizeof(struct GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded) + sizeof(uint64_t)];
+  GNUNET_HashCode result;
+  unsigned int i;  
+  
+  proof_task = GNUNET_SCHEDULER_NO_TASK;
+  memcpy (&buf[sizeof(uint64_t)],
+         &my_public_key, 
+         sizeof(struct GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded));
+  i = 0;
+  counter = my_proof;
+  while ( (counter != UINT64_MAX) && (i < ROUND_SIZE) )
     {
-      GNUNET_CORE_disconnect(coreAPI);
-      coreAPI = NULL;
+      memcpy (buf,
+             &counter, 
+             sizeof(uint64_t));
+      GNUNET_CRYPTO_hash (buf, sizeof (buf), &result);
+      if (nse_work_required <= count_leading_zeroes(&result))
+       {
+         my_proof = counter;
+#if DEBUG_NSE
+         GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+                     "Proof of work found: %llu!\n",
+                     (unsigned long long) GNUNET_ntohll (counter));
+#endif
+         for (i=0;i<HISTORY_SIZE;i++)      
+           if (ntohl (size_estimate_messages[i].hop_count) == 0) 
+             {
+               size_estimate_messages[i].proof_of_work = my_proof;
+               GNUNET_CRYPTO_rsa_sign (my_private_key, 
+                                       &size_estimate_messages[i].purpose,
+                                       &size_estimate_messages[i].signature);
+             }
+         write_proof ();
+         return;
+       }
+      counter++;
+      i++;
+    }
+  if (my_proof / (100 * ROUND_SIZE) < counter / (100 * ROUND_SIZE))
+    {
+#if DEBUG_NSE
+      GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+                 "Testing proofs currently at %llu\n",
+                 (unsigned long long) counter);
+#endif
+      /* remember progress every 100 rounds */
+      my_proof = counter;
+      write_proof (); 
+    }
+  else
+    {
+      my_proof = counter;
+    }
+  proof_task = GNUNET_SCHEDULER_add_delayed (proof_find_delay,
+                                            &find_proof,
+                                            NULL);
+}
+
+
+/**
+ * An incoming flood message has been received which claims
+ * to have more bits matching than any we know in this time
+ * period.  Verify the signature and/or proof of work.
+ *
+ * @param incoming_flood the message to verify
+ *
+ * @return GNUNET_YES if the message is verified
+ *         GNUNET_NO if the key/signature don't verify
+ */
+static int 
+verify_message_crypto(const struct GNUNET_NSE_FloodMessage *incoming_flood)
+{
+  if (GNUNET_YES !=
+      check_proof_of_work (&incoming_flood->pkey,
+                          incoming_flood->proof_of_work))
+    {
+      GNUNET_log (GNUNET_ERROR_TYPE_INFO,
+                 _("Proof of work invalid: %llu!\n"),
+                 (unsigned long long) GNUNET_ntohll (incoming_flood->proof_of_work));
+      GNUNET_break_op (0);
+      return GNUNET_NO;
+    }
+  if (GNUNET_OK != 
+      GNUNET_CRYPTO_rsa_verify (GNUNET_SIGNATURE_PURPOSE_NSE_SEND,
+                               &incoming_flood->purpose,
+                               &incoming_flood->signature,
+                               &incoming_flood->pkey))
+    {
+      GNUNET_break_op (0);
+      return GNUNET_NO;
+    }
+  return GNUNET_YES;
+}
+
+
+/**
+ * Update transmissions for the given peer for the current round based
+ * on updated proximity information.
+ *
+ * @param cls peer entry to exclude from updates
+ * @param key hash of peer identity
+ * @param value the 'struct NSEPeerEntry'
+ * @return GNUNET_OK (continue to iterate)
+ */
+static int
+update_flood_times (void *cls,
+                   const GNUNET_HashCode *key,
+                   void *value)
+{
+  struct NSEPeerEntry *exclude = cls;
+  struct NSEPeerEntry *peer_entry = value;
+  struct GNUNET_TIME_Relative delay;
+
+  if (peer_entry->th != NULL)
+    return GNUNET_OK; /* already active */
+  if (peer_entry == exclude)
+    return GNUNET_OK; /* trigger of the update */
+  if (peer_entry->previous_round == GNUNET_NO)
+    {
+      /* still stuck in previous round, no point to update, check that 
+        we are active here though... */
+#if SEND_ON_CONNECT
+      GNUNET_break (peer_entry->transmit_task != GNUNET_SCHEDULER_NO_TASK);
+#endif
+      return GNUNET_OK; 
+    }
+  if (peer_entry->transmit_task != GNUNET_SCHEDULER_NO_TASK)
+    {
+      GNUNET_SCHEDULER_cancel (peer_entry->transmit_task);
+      peer_entry->transmit_task = GNUNET_SCHEDULER_NO_TASK;
+    }
+  delay = get_transmit_delay (0);
+  peer_entry->transmit_task = GNUNET_SCHEDULER_add_delayed (delay,
+                                                           &transmit_task,
+                                                           peer_entry);
+  return GNUNET_OK;
+}
+
+
+/**
+ * Core handler for size estimate flooding messages.
+ *
+ * @param cls closure unused
+ * @param message message
+ * @param peer peer identity this message is from (ignored)
+ * @param atsi performance data (ignored)
+ *
+ */
+static int
+handle_p2p_size_estimate(void *cls, 
+                        const struct GNUNET_PeerIdentity *peer,
+                         const struct GNUNET_MessageHeader *message,
+                         const struct GNUNET_TRANSPORT_ATS_Information *atsi)
+{
+  const struct GNUNET_NSE_FloodMessage *incoming_flood;
+  struct GNUNET_TIME_Absolute ts;
+  struct NSEPeerEntry *peer_entry;
+  uint32_t matching_bits;  
+  unsigned int idx;
+
+#if ENABLE_HISTOGRAM
+  if (NULL != wh)
+    GNUNET_BIO_write_int64 (wh, GNUNET_TIME_absolute_get ().abs_value);
+#endif
+  incoming_flood = (const struct GNUNET_NSE_FloodMessage *) message;
+  GNUNET_STATISTICS_update (stats, 
+                           "# flood messages received", 
+                           1,
+                           GNUNET_NO);
+  matching_bits = ntohl (incoming_flood->matching_bits);
+#if DEBUG_NSE
+  {
+    char origin[5];
+    char pred[5];
+    struct GNUNET_PeerIdentity os;
+
+    GNUNET_CRYPTO_hash (&incoming_flood->pkey,
+                       sizeof (struct GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded),
+                       &os.hashPubKey);
+    GNUNET_snprintf (origin, sizeof (origin),
+                    "%s",
+                    GNUNET_i2s (&os));
+    GNUNET_snprintf (pred, sizeof (pred),
+                    "%s",
+                    GNUNET_i2s (peer));
+    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+               "Flood at %llu from `%s' via `%s' at `%s' with bits %u\n",
+               (unsigned long long) GNUNET_TIME_absolute_ntoh (incoming_flood->timestamp).abs_value,
+               origin,
+               pred,
+               GNUNET_i2s (&my_identity),
+               (unsigned int) matching_bits);
+  }
+#endif  
+
+  peer_entry = GNUNET_CONTAINER_multihashmap_get (peers, &peer->hashPubKey);
+  if (NULL == peer_entry)
+    {
+      GNUNET_break (0);
+      return GNUNET_OK;
+    }
+
+  ts = GNUNET_TIME_absolute_ntoh (incoming_flood->timestamp);
+
+  if (ts.abs_value == current_timestamp.abs_value)
+    idx = estimate_index;
+  else if (ts.abs_value == current_timestamp.abs_value - gnunet_nse_interval.rel_value)
+    idx = (estimate_index + HISTORY_SIZE - 1) % HISTORY_SIZE;
+  else if (ts.abs_value == next_timestamp.abs_value - gnunet_nse_interval.rel_value)
+    {
+      if (matching_bits <= ntohl (next_message.matching_bits))
+       return GNUNET_OK; /* ignore, simply too early/late */
+      if (GNUNET_YES !=
+         verify_message_crypto (incoming_flood))
+       {
+         GNUNET_break_op (0);
+         return GNUNET_OK;
+       }
+      next_message = *incoming_flood;
+      return GNUNET_OK;
+    }
+  else
+    {
+      GNUNET_STATISTICS_update (stats,
+                                "# flood messages discarded (clock skew too large)",
+                               1,
+                                GNUNET_NO);
+      return GNUNET_OK;
+    }
+  if (0 == (memcmp (peer, &my_identity, sizeof(struct GNUNET_PeerIdentity))))
+    {
+      /* send to self, update our own estimate IF this also comes from us! */
+      if (0 == memcmp (&incoming_flood->pkey,
+                      &my_public_key,
+                      sizeof (my_public_key)))                
+       update_network_size_estimate ();
+      return GNUNET_OK; 
     }
+  if (matching_bits >= ntohl (size_estimate_messages[idx].matching_bits))        
+    {      
+      /* cancel transmission from us to this peer for this round */
+      if (idx == estimate_index)
+       {
+         if (peer_entry->previous_round == GNUNET_YES)
+           {
+             /* cancel any activity for current round */
+             if (peer_entry->transmit_task != GNUNET_SCHEDULER_NO_TASK)
+               {
+                 GNUNET_SCHEDULER_cancel (peer_entry->transmit_task);
+                 peer_entry->transmit_task = GNUNET_SCHEDULER_NO_TASK;
+               }
+             if (peer_entry->th != NULL)
+               {
+                 GNUNET_CORE_notify_transmit_ready_cancel (peer_entry->th);
+                 peer_entry->th = NULL;
+               }
+           }
+       }
+      else
+       {
+         /* cancel previous round only */
+         peer_entry->previous_round = GNUNET_YES;
+       } 
+    }
+  if (matching_bits <= ntohl (size_estimate_messages[idx].matching_bits)) 
+    {
+      if ( (idx < estimate_index) &&
+          (peer_entry->previous_round == GNUNET_YES) )
+       peer_entry->previous_round = GNUNET_NO;
+      /* push back our result now, that peer is spreading bad information... */
+      if (peer_entry->transmit_task != GNUNET_SCHEDULER_NO_TASK)
+       GNUNET_SCHEDULER_cancel (peer_entry->transmit_task);
+      peer_entry->transmit_task = GNUNET_SCHEDULER_add_now (&transmit_task,
+                                                           peer_entry);          
+      /* Not closer than our most recent message, no need to do work here */
+      GNUNET_STATISTICS_update (stats,
+                                "# flood messages ignored (had closer already)",
+                               1,
+                                GNUNET_NO);
+      return GNUNET_OK;
+    }
+  if (GNUNET_YES !=
+      verify_message_crypto (incoming_flood))
+    {
+      GNUNET_break_op (0);
+      return GNUNET_OK;
+    }
+  size_estimate_messages[idx] = *incoming_flood;
+  size_estimate_messages[idx].hop_count = htonl (ntohl (incoming_flood->hop_count) + 1);
+  hop_count_max = GNUNET_MAX (ntohl (incoming_flood->hop_count) + 1,
+                             hop_count_max);
+
+  /* have a new, better size estimate, inform clients */
+  update_network_size_estimate ();
 
+  /* flood to rest */
+  GNUNET_CONTAINER_multihashmap_iterate (peers,
+                                        &update_flood_times,
+                                        peer_entry);
+  return GNUNET_OK;
 }
 
 
+
 /**
- * Task to schedule a flood message to be sent.
+ * Method called whenever a peer connects.
  *
  * @param cls closure
- * @param tc context information (why was this task triggered now)
+ * @param peer peer identity this notification is about
+ * @param atsi performance data
  */
-static void schedule_flood_message (void *cls,
-                                    const struct
-                                    GNUNET_SCHEDULER_TaskContext * tc)
+static void
+handle_core_connect(void *cls, const struct GNUNET_PeerIdentity *peer,
+                    const struct GNUNET_TRANSPORT_ATS_Information *atsi)
 {
-  GNUNET_HashCode timestamp_hash;
-  struct GNUNET_TIME_Absolute curr_time;
-  unsigned int matching_bits;
-
-  /* Get the current UTC time */
-  curr_time = GNUNET_TIME_absolute_get();
-  /* Find the previous interval start time */
-  previous_timestamp.abs_value = (curr_time.abs_value / GNUNET_NSE_INTERVAL) * GNUNET_NSE_INTERVAL;
-  /* Find the next interval start time */
-  next_timestamp.abs_value = (curr_time.abs_value / GNUNET_NSE_INTERVAL) * (GNUNET_NSE_INTERVAL + 1);
-
-  GNUNET_CRYPTO_hash(&next_timestamp.abs_value, sizeof(uint64_t), &timestamp_hash);
-  matching_bits = GNUNET_CRYPTO_hash_matching_bits(&timestamp_hash, &my_identity.hashPubKey);
-
-  GNUNET_SCHEDULER_add_delayed (
-                                GNUNET_TIME_relative_add (
-                                                          GNUNET_TIME_relative_multiply (
-                                                                                         increment,
-                                                                                         matching_bits),
-                                                          GNUNET_TIME_absolute_get_remaining (
-                                                                                              next_timestamp)),
-                                &send_flood_message, NULL);
+  struct NSEPeerEntry *peer_entry;
+
+ #if DEBUG_NSE
+  GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, 
+            "Peer `%s' connected to us\n",
+            GNUNET_i2s (peer));
+#endif
+  peer_entry = GNUNET_malloc(sizeof(struct NSEPeerEntry));
+  peer_entry->id = *peer;
+  GNUNET_CONTAINER_multihashmap_put (peers,
+                                    &peer->hashPubKey,
+                                    peer_entry,
+                                    GNUNET_CONTAINER_MULTIHASHMAPOPTION_UNIQUE_ONLY);
+#if SEND_ON_CONNECT
+  peer_entry->transmit_task = GNUNET_SCHEDULER_add_delayed (get_transmit_delay (-1),
+                                                           &transmit_task,
+                                                           peer_entry);
+#endif
+}
+
+
+/**
+ * Method called whenever a peer disconnects.
+ *
+ * @param cls closure
+ * @param peer peer identity this notification is about
+ */
+static void
+handle_core_disconnect(void *cls, const struct GNUNET_PeerIdentity *peer)
+{
+  struct NSEPeerEntry *pos;
+
+ #if DEBUG_NSE
+  GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, 
+            "Peer `%s' disconnected from us\n",
+            GNUNET_i2s (peer));
+#endif
+ pos = GNUNET_CONTAINER_multihashmap_get (peers,
+                                          &peer->hashPubKey);
+  if (NULL == pos)
+    {
+      GNUNET_break (0);
+      return;
+    }
+  GNUNET_assert (GNUNET_YES ==
+                GNUNET_CONTAINER_multihashmap_remove (peers, 
+                                                      &peer->hashPubKey,
+                                                      pos));
+  if (pos->transmit_task != GNUNET_SCHEDULER_NO_TASK)
+    GNUNET_SCHEDULER_cancel (pos->transmit_task);
+  if (pos->th != NULL)
+    GNUNET_CORE_notify_transmit_ready_cancel (pos->th);
+  GNUNET_free(pos);
+}
+
+
+/**
+ * Task run during shutdown.
+ *
+ * @param cls unused
+ * @param tc unused
+ */
+static void
+shutdown_task(void *cls,
+             const struct GNUNET_SCHEDULER_TaskContext *tc)
+{
+  if (flood_task != GNUNET_SCHEDULER_NO_TASK)
+    {
+      GNUNET_SCHEDULER_cancel (flood_task);
+      flood_task = GNUNET_SCHEDULER_NO_TASK;
+    }
+  if (proof_task != GNUNET_SCHEDULER_NO_TASK)
+    {
+      GNUNET_SCHEDULER_cancel (proof_task);
+      proof_task = GNUNET_SCHEDULER_NO_TASK;
+      write_proof (); /* remember progress */
+    }
+  if (nc != NULL)
+    {
+      GNUNET_SERVER_notification_context_destroy (nc);
+      nc = NULL;
+    }
+  if (coreAPI != NULL)
+    {
+      GNUNET_CORE_disconnect (coreAPI);
+      coreAPI = NULL;
+    }
+  if (stats != NULL)
+    {
+      GNUNET_STATISTICS_destroy (stats, GNUNET_NO);
+      stats = NULL;
+    }
+  if (peers != NULL)
+    {
+      GNUNET_CONTAINER_multihashmap_destroy (peers);
+      peers = NULL;
+    }
+  if (my_private_key != NULL)
+    {
+      GNUNET_CRYPTO_rsa_key_free (my_private_key);
+      my_private_key = NULL;
+    }
+#if ENABLE_HISTOGRAM
+  if (wh != NULL)
+    {
+      GNUNET_BIO_write_close (wh);
+      wh = NULL;
+    }
+#endif
 }
 
+
 /**
  * Called on core init/fail.
  *
@@ -316,34 +1237,42 @@ static void schedule_flood_message (void *cls,
  * @param identity the public identity of this peer
  * @param publicKey the public key of this peer
  */
-void
-core_init (void *cls,
-           struct GNUNET_CORE_Handle *server,
-           const struct GNUNET_PeerIdentity *identity,
-           const struct GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded *publicKey)
+static void
+core_init (void *cls, struct GNUNET_CORE_Handle *server,
+          const struct GNUNET_PeerIdentity *identity,
+          const struct GNUNET_CRYPTO_RsaPublicKeyBinaryEncoded *publicKey)
 {
+  struct GNUNET_TIME_Absolute now;
+  struct GNUNET_TIME_Absolute prev_time;
+  unsigned int i;
+
   if (server == NULL)
     {
 #if DEBUG_NSE
-      GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
-                  "%s: Connection to core FAILED!\n", "nse",
-                  GNUNET_i2s (identity));
+      GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, 
+                 "Connection to core FAILED!\n");
 #endif
-      GNUNET_SCHEDULER_add_now (&shutdown_task, NULL);
+      GNUNET_SCHEDULER_shutdown ();
       return;
     }
-#if DEBUG_NSE
-  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
-              "%s: Core connection initialized, I am peer: %s\n", "nse",
-              GNUNET_i2s (identity));
-#endif
-
-  /* Copy our identity so we can use it */
-  memcpy (&my_identity, identity, sizeof (struct GNUNET_PeerIdentity));
-
-  flood_task = GNUNET_SCHEDULER_add_now(&schedule_flood_message, NULL);
+  GNUNET_assert (0 == memcmp (&my_identity, identity, sizeof (struct GNUNET_PeerIdentity)));
+  now = GNUNET_TIME_absolute_get ();
+  current_timestamp.abs_value = (now.abs_value / gnunet_nse_interval.rel_value) * gnunet_nse_interval.rel_value;
+  next_timestamp.abs_value = current_timestamp.abs_value + gnunet_nse_interval.rel_value;
+  
+  for (i = 0; i < HISTORY_SIZE; i++)
+    {
+      prev_time.abs_value = current_timestamp.abs_value - (HISTORY_SIZE - i - 1) * gnunet_nse_interval.rel_value;
+      setup_flood_message (i, prev_time);
+    }
+  estimate_index = HISTORY_SIZE - 1;
+  estimate_count = 2;
+  flood_task
+    = GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_absolute_get_remaining (next_timestamp),
+                                   &update_flood_message, NULL);
 }
 
+
 /**
  * Handle network size estimate clients.
  *
@@ -352,64 +1281,132 @@ core_init (void *cls,
  * @param c configuration to use
  */
 static void
-run (void *cls,
-     struct GNUNET_SERVER_Handle *server,
-     const struct GNUNET_CONFIGURATION_Handle *c)
+run(void *cls, struct GNUNET_SERVER_Handle *server,
+    const struct GNUNET_CONFIGURATION_Handle *c)
 {
-  static const struct GNUNET_SERVER_MessageHandler handlers[] = {
-    {&handle_start_message, NULL, GNUNET_MESSAGE_TYPE_NSE_START, 0},
-    {NULL, NULL, 0, 0}
-  };
-
-  static const struct GNUNET_CORE_MessageHandler core_handlers[] = {
-    {&handle_p2p_size_estimate, GNUNET_MESSAGE_TYPE_NSE_P2P_FLOOD, 0},
-    {NULL, 0, 0}
-  };
+  char *keyfile;
+  char *proof;
 
+  static const struct GNUNET_SERVER_MessageHandler handlers[] =
+    {
+      { &handle_start_message, NULL, GNUNET_MESSAGE_TYPE_NSE_START, sizeof (struct GNUNET_MessageHeader) },
+      { NULL, NULL, 0, 0 } 
+    };
+  static const struct GNUNET_CORE_MessageHandler core_handlers[] =
+    {
+      { &handle_p2p_size_estimate, GNUNET_MESSAGE_TYPE_NSE_P2P_FLOOD, sizeof (struct GNUNET_NSE_FloodMessage) },
+      { NULL, 0, 0 } 
+    };
   cfg = c;
-  GNUNET_SERVER_add_handlers (server, handlers);
-  nc = GNUNET_SERVER_notification_context_create (server, 16);
-  GNUNET_SERVER_disconnect_notify (server,
-                                   &handle_client_disconnect,
-                                   NULL);
-
-  /** Connect to core service and register core handlers */
-  coreAPI = GNUNET_CORE_connect (cfg,   /* Main configuration */
-                                 DEFAULT_CORE_QUEUE_SIZE,       /* queue size */
-                                 NULL,  /* Closure passed to functions */
-                                 &core_init,    /* Call core_init once connected */
-                                 NULL,  /* Handle connects */
-                                 NULL,       /* Handle disconnects */
-                                 NULL,  /* Do we care about "status" updates? */
-                                 NULL,  /* Don't want notified about all incoming messages */
-                                 GNUNET_NO,     /* For header only inbound notification */
-                                 NULL,  /* Don't want notified about all outbound messages */
-                                 GNUNET_NO,     /* For header only outbound notification */
-                                 core_handlers);        /* Register these handlers */
 
-  if (coreAPI == NULL)
+  if ( (GNUNET_OK != 
+       GNUNET_CONFIGURATION_get_value_time (cfg,
+                                            "NSE", "INTERVAL",
+                                            &gnunet_nse_interval)) ||
+       (GNUNET_OK != 
+       GNUNET_CONFIGURATION_get_value_time (cfg,
+                                            "NSE", "WORKDELAY",
+                                            &proof_find_delay)) ||
+       (GNUNET_OK != 
+       GNUNET_CONFIGURATION_get_value_number (cfg,
+                                              "NSE", "WORKBITS",
+                                              &nse_work_required)) )       
+    {
+      GNUNET_log (GNUNET_ERROR_TYPE_ERROR, 
+                 _ ("NSE service is lacking key configuration settings.  Exiting.\n"));
+      GNUNET_SCHEDULER_shutdown ();
+      return;
+    }
+  if (nse_work_required >= sizeof (GNUNET_HashCode) * 8)
     {
-      GNUNET_SCHEDULER_add_now (&shutdown_task, NULL);
+      GNUNET_log (GNUNET_ERROR_TYPE_ERROR, 
+                 _ ("Invalid work requirement for NSE service. Exiting.\n"));
+      GNUNET_SCHEDULER_shutdown ();
       return;
     }
 
-  increment
-      = GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_MILLISECONDS,
-                                       GNUNET_NSE_INTERVAL
-                                           / (sizeof(GNUNET_HashCode)
-                                               * 8));
-  /* Set we have no idea defaults for network size estimate */
-  current_size_estimate = NAN;
-  current_std_dev = NAN;
 
-  current_estimate_message.header.size = htons(sizeof(struct GNUNET_NSE_ClientMessage));
-  current_estimate_message.header.type = htons(GNUNET_MESSAGE_TYPE_NSE_ESTIMATE);
-  current_estimate_message.size_estimate = current_size_estimate;
-  current_estimate_message.std_deviation = current_std_dev;
+  if (GNUNET_OK != 
+      GNUNET_CONFIGURATION_get_value_filename (cfg,
+                                              "GNUNETD", "HOSTKEY",
+                                              &keyfile))
+    {
+      GNUNET_log (GNUNET_ERROR_TYPE_ERROR, 
+                 _ ("NSE service is lacking key configuration settings.  Exiting.\n"));
+      GNUNET_SCHEDULER_shutdown ();
+      return;
+    }
+  my_private_key = GNUNET_CRYPTO_rsa_key_create_from_file (keyfile);
+  GNUNET_free (keyfile);
+  if (my_private_key == NULL)
+    {
+      GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
+                  _("NSE service could not access hostkey.  Exiting.\n"));
+      GNUNET_SCHEDULER_shutdown ();
+      return;
+    }
+  GNUNET_CRYPTO_rsa_key_get_public (my_private_key, &my_public_key);
+  GNUNET_CRYPTO_hash (&my_public_key, sizeof (my_public_key), &my_identity.hashPubKey);
+  if (GNUNET_OK != 
+      GNUNET_CONFIGURATION_get_value_filename (cfg,
+                                              "NSE", "PROOFFILE",
+                                              &proof))
+    {
+      GNUNET_log (GNUNET_ERROR_TYPE_ERROR, 
+                 _ ("NSE service is lacking key configuration settings.  Exiting.\n"));
+      if (my_private_key != NULL)
+       {
+         GNUNET_CRYPTO_rsa_key_free (my_private_key);
+         my_private_key = NULL;
+       }
+      GNUNET_SCHEDULER_shutdown ();
+      return;
+    }
+  if ( (GNUNET_YES != GNUNET_DISK_file_test (proof)) ||
+       (sizeof (my_proof) !=
+       GNUNET_DISK_fn_read (proof,
+                            &my_proof,
+                            sizeof (my_proof))) )
+    my_proof = 0; 
+  GNUNET_free (proof);
+  proof_task = GNUNET_SCHEDULER_add_with_priority (GNUNET_SCHEDULER_PRIORITY_IDLE,
+                                                  &find_proof,
+                                                  NULL);
 
+  peers = GNUNET_CONTAINER_multihashmap_create (128);
+  GNUNET_SERVER_add_handlers (server, handlers);
+  nc = GNUNET_SERVER_notification_context_create (server, 1);
+  /* Connect to core service and register core handlers */
+  coreAPI = GNUNET_CORE_connect (cfg, /* Main configuration */
+                                CORE_QUEUE_SIZE, /* queue size */
+                                NULL, /* Closure passed to functions */
+                                &core_init, /* Call core_init once connected */
+                                &handle_core_connect, /* Handle connects */
+                                &handle_core_disconnect, /* Handle disconnects */
+                                NULL, /* Do we care about "status" updates? */
+                                NULL, /* Don't want notified about all incoming messages */
+                                GNUNET_NO, /* For header only inbound notification */
+                                NULL, /* Don't want notified about all outbound messages */
+                                GNUNET_NO, /* For header only outbound notification */
+                                core_handlers); /* Register these handlers */
   GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_UNIT_FOREVER_REL,
-                                &shutdown_task,
-                                NULL);
+                               &shutdown_task, NULL);
+#if ENABLE_HISTOGRAM
+  if (GNUNET_OK == 
+      GNUNET_CONFIGURATION_get_value_filename (cfg,
+                                              "NSE", "HISTOGRAM",
+                                              &proof))
+    {
+      wh = GNUNET_BIO_write_open (proof);
+      GNUNET_free (proof);
+    }
+#endif
+  if (coreAPI == NULL)
+    {
+      GNUNET_SCHEDULER_shutdown ();
+      return;
+    }
+  stats = GNUNET_STATISTICS_create ("nse", cfg);
 }
 
 
@@ -421,15 +1418,13 @@ run (void *cls,
  * @return 0 ok, 1 on error
  */
 int
-main (int argc, char *const *argv)
+main(int argc, char * const *argv)
 {
-  return (GNUNET_OK ==
-          GNUNET_SERVICE_run (argc,
-                              argv,
-                              "nse",
-                              GNUNET_SERVICE_OPTION_NONE,
-                              &run, NULL)) ? 0 : 1;
+  return (GNUNET_OK == GNUNET_SERVICE_run (argc, argv, 
+                                          "nse",
+                                           GNUNET_SERVICE_OPTION_NONE, &run,
+                                           NULL)) ? 0 : 1;
 }
 
-/* End of gnunet-service-nse.c */
+/* end of gnunet-service-nse.c */