use new SCHEDULER_add_at API where applicable
[oweals/gnunet.git] / src / topology / gnunet-daemon-topology.c
index 147e7332a26d35958975018dd089faab4b6eac55..067ebce238890b34cbaffd2abb3c3890065bea5c 100644 (file)
@@ -1,6 +1,6 @@
 /*
      This file is part of GNUnet.
-     (C) 2007-2013 Christian Grothoff (and other contributing authors)
+     Copyright (C) 2007-2016 GNUnet e.V.
 
      GNUnet is free software; you can redistribute it and/or modify
      it under the terms of the GNU General Public License as published
 
      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.
+     Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+     Boston, MA 02110-1301, USA.
 */
 
 /**
  * @file topology/gnunet-daemon-topology.c
- * @brief code for maintaining the cadet topology
+ * @brief code for maintaining the overlay topology
  * @author Christian Grothoff
+ *
+ * This daemon combines three functions:
+ * - suggesting to ATS which peers we might want to connect to
+ * - enforcing the F2F restrictions (by blacklisting)
+ * - gossping HELLOs
+ *
+ * All three require similar information (who are our friends
+ * impacts connectivity suggestions; connectivity suggestions
+ * should consider blacklisting; connectivity suggestions
+ * should consider available/known HELLOs; gossip requires
+ * connectivity data; connectivity suggestions require
+ * connectivity data), which is why they are combined in this
+ * program.
  */
 #include "platform.h"
 #include "gnunet_util_lib.h"
 #include "gnunet_peerinfo_service.h"
 #include "gnunet_statistics_service.h"
 #include "gnunet_transport_service.h"
+#include "gnunet_ats_service.h"
 
 
-/**
- * Minimum required delay between calls to GNUNET_TRANSPORT_try_connect.
- */
-#define MAX_CONNECT_FREQUENCY_DELAY GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_MILLISECONDS, 250)
-
-/**
- * Maximum delay allowed delay between calls to GNUNET_TRANSPORT_try_connect.
- */
-#define MIN_CONNECT_FREQUENCY_DELAY GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_MILLISECONDS, 2500)
-
-/**
- * For how long do we blacklist a peer after a failed connection
- * attempt?  This is the baseline factor which is then multiplied by
- * two to the power of the number of failed attempts.
- */
-#define GREYLIST_AFTER_ATTEMPT GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_MINUTES, 1)
-
-/**
- * For how long do we blacklist a friend after a failed connection
- * attempt?  This is the baseline factor which is then multiplied by
- * two to the power of the number of failed attempts.
- */
-#define GREYLIST_AFTER_ATTEMPT_FRIEND GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_SECONDS, 2)
-
-/**
- * For how long do we blacklist anyone under any cirumstances at least after a failed connection
- * attempt?  This is the absolute minimum, regardless of what the calculation based on
- * exponential backoff returns.
- */
-#define GREYLIST_AFTER_ATTEMPT_MIN GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_SECONDS, 5)
-
-/**
- * For how long do we blacklist anyone under any cirumstances at most after a failed connection
- * attempt?  This is the absolute maximum, regardless of what the calculation based on
- * exponential back-off returns.
- */
-#define GREYLIST_AFTER_ATTEMPT_MAX GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_HOURS, 1)
-
 /**
  * At what frequency do we sent HELLOs to a peer?
  */
@@ -94,10 +70,10 @@ struct Peer
   struct GNUNET_PeerIdentity pid;
 
   /**
-   * Our handle for the request to transmit HELLOs to this peer; NULL
-   * if no such request is pending.
+   * Our handle for transmitting to this peer; NULL
+   * if peer is not connected.
    */
-  struct GNUNET_CORE_TransmitHandle *hello_req;
+  struct GNUNET_MQ_Handle *mq;
 
   /**
    * Pointer to the HELLO message of this peer; can be NULL.
@@ -110,12 +86,6 @@ struct Peer
    */
   struct GNUNET_CONTAINER_BloomFilter *filter;
 
-  /**
-   * Until what time should we not try to connect again
-   * to this peer?
-   */
-  struct GNUNET_TIME_Absolute greylisted_until;
-
   /**
    * Next time we are allowed to transmit a HELLO to this peer?
    */
@@ -130,33 +100,23 @@ struct Peer
    * ID of task we use to wait for the time to send the next HELLO
    * to this peer.
    */
-  GNUNET_SCHEDULER_TaskIdentifier hello_delay_task;
-
-  /**
-   * Task for issuing GNUNET_TRANSPORT_try_connect for this peer.
-   */
-  GNUNET_SCHEDULER_TaskIdentifier attempt_connect_task;
+  struct GNUNET_SCHEDULER_Task *hello_delay_task;
 
   /**
-   * ID of task we use to clear peers from the greylist.
+   * Handle for our connectivity suggestion for this peer.
    */
-  GNUNET_SCHEDULER_TaskIdentifier greylist_clean_task;
+  struct GNUNET_ATS_ConnectivitySuggestHandle *sh;
 
   /**
-   * How often have we tried so far?
+   * How much would we like to connect to this peer?
    */
-  unsigned int connect_attempts;
+  uint32_t strength;
 
   /**
    * Is this peer listed here because he is a friend?
    */
   int is_friend;
 
-  /**
-   * Are we connected to this peer right now?
-   */
-  int is_connected;
-
 };
 
 
@@ -172,14 +132,14 @@ static struct GNUNET_PEERINFO_NotifyContext *peerinfo_notify;
 static const struct GNUNET_CONFIGURATION_Handle *cfg;
 
 /**
- * Handle to the core API.
+ * Handle to the CORE service.
  */
 static struct GNUNET_CORE_Handle *handle;
 
 /**
- * Handle to the transport API.
+ * Handle to the ATS service.
  */
-static struct GNUNET_TRANSPORT_Handle *transport;
+static struct GNUNET_ATS_ConnectivityHandle *ats;
 
 /**
  * Identity of this peer.
@@ -189,7 +149,7 @@ static struct GNUNET_PeerIdentity my_identity;
 /**
  * All of our friends, all of our current neighbours and all peers for
  * which we have HELLOs.  So pretty much everyone.  Maps peer identities
- * to 'struct Peer *' values.
+ * to `struct Peer *` values.
  */
 static struct GNUNET_CONTAINER_MultiPeerMap *peers;
 
@@ -204,14 +164,15 @@ static struct GNUNET_STATISTICS_Handle *stats;
 static struct GNUNET_TRANSPORT_Blacklist *blacklist;
 
 /**
- * When can we next ask transport to create a connection?
+ * Task scheduled to asynchronously reconsider adding/removing
+ * peer connectivity suggestions.
  */
-static struct GNUNET_TIME_Absolute next_connect_attempt;
+static struct GNUNET_SCHEDULER_Task *add_task;
 
 /**
- * Task scheduled to try to add peers.
+ * Active HELLO offering to transport service.
  */
-static GNUNET_SCHEDULER_TaskIdentifier add_task;
+static struct GNUNET_TRANSPORT_OfferHelloHandle *oh;
 
 /**
  * Flag to disallow non-friend connections (pure F2F mode).
@@ -246,18 +207,23 @@ static unsigned int friend_count;
  * is rather simple.
  *
  * @param cls closure
- * @param pid peer to approve or disapproave
- * @return GNUNET_OK if the connection is allowed
+ * @param pid peer to approve or disapprove
+ * @return #GNUNET_OK if the connection is allowed
  */
 static int
-blacklist_check (void *cls, const struct GNUNET_PeerIdentity *pid)
+blacklist_check (void *cls,
+                 const struct GNUNET_PeerIdentity *pid)
 {
   struct Peer *pos;
 
-  pos = GNUNET_CONTAINER_multipeermap_get (peers, pid);
-  if ((pos != NULL) && (pos->is_friend == GNUNET_YES))
+  pos = GNUNET_CONTAINER_multipeermap_get (peers,
+                                           pid);
+  if ( (NULL != pos) &&
+       (GNUNET_YES == pos->is_friend))
     return GNUNET_OK;
-  GNUNET_STATISTICS_update (stats, gettext_noop ("# peers blacklisted"), 1,
+  GNUNET_STATISTICS_update (stats,
+                            gettext_noop ("# peers blacklisted"),
+                            1,
                             GNUNET_NO);
   return GNUNET_SYSERR;
 }
@@ -270,7 +236,7 @@ blacklist_check (void *cls, const struct GNUNET_PeerIdentity *pid)
 static void
 whitelist_peers ()
 {
-  if (blacklist != NULL)
+  if (NULL != blacklist)
   {
     GNUNET_TRANSPORT_blacklist_cancel (blacklist);
     blacklist = NULL;
@@ -278,201 +244,104 @@ whitelist_peers ()
 }
 
 
-/**
- * Check if an additional connection from the given peer is allowed.
- *
- * @param peer connection to check
- * @return GNUNET_OK if the connection is allowed
- */
-static int
-is_connection_allowed (struct Peer *peer)
-{
-  if (0 ==
-      memcmp (&my_identity, &peer->pid, sizeof (struct GNUNET_PeerIdentity)))
-    return GNUNET_SYSERR;       /* disallow connections to self */
-  if (peer->is_friend)
-    return GNUNET_OK;
-  if (GNUNET_YES == friends_only)
-  {
-    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
-                "Determined that `%s' is not allowed to connect (not a friend)\n",
-                GNUNET_i2s (&peer->pid));
-    return GNUNET_SYSERR;
-  }
-  if (friend_count >= minimum_friend_count)
-    return GNUNET_OK;
-  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
-              "Determined that `%s' is not allowed to connect (not enough connected friends)\n",
-              GNUNET_i2s (&peer->pid));
-  return GNUNET_SYSERR;
-}
-
-
 /**
  * Free all resources associated with the given peer.
  *
  * @param cls closure (not used)
  * @param pid identity of the peer
  * @param value peer to free
- * @return GNUNET_YES (always: continue to iterate)
+ * @return #GNUNET_YES (always: continue to iterate)
  */
 static int
-free_peer (void *cls, const struct GNUNET_PeerIdentity * pid, void *value)
+free_peer (void *cls,
+           const struct GNUNET_PeerIdentity * pid,
+           void *value)
 {
   struct Peer *pos = value;
 
-  GNUNET_break (GNUNET_NO == pos->is_connected);
+  GNUNET_break (NULL == pos->mq);
   GNUNET_break (GNUNET_OK ==
-                GNUNET_CONTAINER_multipeermap_remove (peers, pid, pos));
-  if (pos->hello_req != NULL)
-    GNUNET_CORE_notify_transmit_ready_cancel (pos->hello_req);
-  if (pos->hello_delay_task != GNUNET_SCHEDULER_NO_TASK)
+                GNUNET_CONTAINER_multipeermap_remove (peers,
+                                                      pid,
+                                                      pos));
+  if (NULL != pos->hello_delay_task)
+  {
     GNUNET_SCHEDULER_cancel (pos->hello_delay_task);
-  if (pos->attempt_connect_task != GNUNET_SCHEDULER_NO_TASK)
-    GNUNET_SCHEDULER_cancel (pos->attempt_connect_task);
-  if (pos->greylist_clean_task != GNUNET_SCHEDULER_NO_TASK)
-    GNUNET_SCHEDULER_cancel (pos->greylist_clean_task);
-  GNUNET_free_non_null (pos->hello);
-  if (pos->filter != NULL)
+    pos->hello_delay_task = NULL;
+  }
+  if (NULL != pos->sh)
+  {
+    GNUNET_ATS_connectivity_suggest_cancel (pos->sh);
+    pos->sh = NULL;
+  }
+  if (NULL != pos->hello)
+  {
+    GNUNET_free_non_null (pos->hello);
+    pos->hello = NULL;
+  }
+  if (NULL != pos->filter)
+  {
     GNUNET_CONTAINER_bloomfilter_free (pos->filter);
+    pos->filter = NULL;
+  }
   GNUNET_free (pos);
   return GNUNET_YES;
 }
 
 
 /**
- * Discard peer entries for greylisted peers
- * where the greylisting has expired.
+ * Recalculate how much we want to be connected to the specified peer
+ * and let ATS know about the result.
  *
- * @param cls 'struct Peer' to greylist
- * @param tc scheduler context
- */
-static void
-remove_from_greylist (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc);
-
-
-/**
- * Try to connect to the specified peer.
- *
- * @param pos peer to connect to
+ * @param pos peer to consider connecting to
  */
 static void
 attempt_connect (struct Peer *pos)
 {
-  struct GNUNET_TIME_Relative rem;
+  uint32_t strength;
 
-  if ((connection_count >= target_connection_count) &&
-      (friend_count >= minimum_friend_count))
-    return;
-  if (GNUNET_YES == pos->is_connected)
-    return;
-  if (GNUNET_OK != is_connection_allowed (pos))
-    return;
-  if (GNUNET_TIME_absolute_get_remaining (pos->greylisted_until).rel_value_us > 0)
-    return;
-  if (GNUNET_YES == pos->is_friend)
-    rem = GREYLIST_AFTER_ATTEMPT_FRIEND;
-  else
-    rem = GREYLIST_AFTER_ATTEMPT;
-  rem = GNUNET_TIME_relative_multiply (rem, connection_count);
-  rem = GNUNET_TIME_relative_divide (rem, target_connection_count);
-  if (pos->connect_attempts > 30)
-    pos->connect_attempts = 30;
+  if (0 ==
+      memcmp (&my_identity,
+              &pos->pid,
+              sizeof (struct GNUNET_PeerIdentity)))
+    return; /* This is myself, nothing to do. */
+  if (connection_count < target_connection_count)
+    strength = 1;
   else
-    pos->connect_attempts ++;
-  rem = GNUNET_TIME_relative_multiply (rem, 1 << pos->connect_attempts);
-  rem = GNUNET_TIME_relative_max (rem, GREYLIST_AFTER_ATTEMPT_MIN);
-  rem = GNUNET_TIME_relative_min (rem, GREYLIST_AFTER_ATTEMPT_MAX);
-  pos->greylisted_until = GNUNET_TIME_relative_to_absolute (rem);
-  if (pos->greylist_clean_task != GNUNET_SCHEDULER_NO_TASK)
-    GNUNET_SCHEDULER_cancel (pos->greylist_clean_task);
-  pos->greylist_clean_task =
-      GNUNET_SCHEDULER_add_delayed (rem, &remove_from_greylist, pos);
-  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Asking  to connect to `%s'\n",
-              GNUNET_i2s (&pos->pid));
-  GNUNET_STATISTICS_update (stats,
-                            gettext_noop
-                            ("# connect requests issued to transport"), 1,
-                            GNUNET_NO);
-  GNUNET_TRANSPORT_try_connect (transport, &pos->pid, NULL, NULL);
-}
-
-
-/**
- * Try to connect to the specified peer.
- *
- * @param cls peer to connect to
- * @param tc scheduler context
- */
-static void
-do_attempt_connect (void *cls,
-                   const struct GNUNET_SCHEDULER_TaskContext *tc)
-{
-  struct Peer *pos = cls;
-  struct GNUNET_TIME_Relative delay;
-
-  pos->attempt_connect_task = GNUNET_SCHEDULER_NO_TASK;
-  if (GNUNET_YES == pos->is_connected)
-    return;
-
-  delay = GNUNET_TIME_absolute_get_remaining (next_connect_attempt);
-  if (delay.rel_value_us > 0)
-  {
-    pos->attempt_connect_task = GNUNET_SCHEDULER_add_delayed (delay,
-                                                             &do_attempt_connect,
-                                                             pos);
-    return;
-  }
-  next_connect_attempt = GNUNET_TIME_relative_to_absolute (MAX_CONNECT_FREQUENCY_DELAY);
-  attempt_connect (pos);
-}
-
-
-/**
- * Schedule a task to try to connect to the specified peer.
- *
- * @param pos peer to connect to
- */
-static void
-schedule_attempt_connect (struct Peer *pos)
-{
-  if (GNUNET_SCHEDULER_NO_TASK != pos->attempt_connect_task)
-    return;
-  pos->attempt_connect_task = GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_absolute_get_remaining (next_connect_attempt),
-                                                           &do_attempt_connect,
-                                                           pos);
-}
-
-
-/**
- * Discard peer entries for greylisted peers
- * where the greylisting has expired.
- *
- * @param cls 'struct Peer' to greylist
- * @param tc scheduler context
- */
-static void
-remove_from_greylist (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
-{
-  struct Peer *pos = cls;
-  struct GNUNET_TIME_Relative rem;
-
-  pos->greylist_clean_task = GNUNET_SCHEDULER_NO_TASK;
-  rem = GNUNET_TIME_absolute_get_remaining (pos->greylisted_until);
-  if (0 == rem.rel_value_us)
+    strength = 0;
+  if ( (friend_count < minimum_friend_count) ||
+       (GNUNET_YES == friends_only) )
   {
-    schedule_attempt_connect (pos);
+    if (pos->is_friend)
+      strength += 10; /* urgently needed */
+    else
+      strength = 0; /* disallowed */
   }
-  else
+  if (pos->is_friend)
+    strength *= 2; /* friends always count more */
+  if (NULL != pos->mq)
+    strength *= 2; /* existing connections preferred */
+  if (strength == pos->strength)
+    return; /* nothing to do */
+  if (NULL != pos->sh)
   {
-    pos->greylist_clean_task =
-        GNUNET_SCHEDULER_add_delayed (rem, &remove_from_greylist, pos);
+    GNUNET_ATS_connectivity_suggest_cancel (pos->sh);
+    pos->sh = NULL;
   }
-  if ((GNUNET_NO == pos->is_friend) && (GNUNET_NO == pos->is_connected) &&
-      (NULL == pos->hello))
+  pos->strength = strength;
+  if (0 != strength)
   {
-    free_peer (NULL, &pos->pid, pos);
-    return;
+    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+                "Asking to connect to `%s' with strength %u\n",
+                GNUNET_i2s (&pos->pid),
+                (unsigned int) strength);
+    GNUNET_STATISTICS_update (stats,
+                              gettext_noop ("# connect requests issued to ATS"),
+                              1,
+                              GNUNET_NO);
+    pos->sh = GNUNET_ATS_connectivity_suggest (ats,
+                                               &pos->pid,
+                                               strength);
   }
 }
 
@@ -487,20 +356,24 @@ remove_from_greylist (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
  */
 static struct Peer *
 make_peer (const struct GNUNET_PeerIdentity *peer,
-           const struct GNUNET_HELLO_Message *hello, int is_friend)
+           const struct GNUNET_HELLO_Message *hello,
+           int is_friend)
 {
   struct Peer *ret;
 
   ret = GNUNET_new (struct Peer);
   ret->pid = *peer;
   ret->is_friend = is_friend;
-  if (hello != NULL)
+  if (NULL != hello)
   {
     ret->hello = GNUNET_malloc (GNUNET_HELLO_size (hello));
-    memcpy (ret->hello, hello, GNUNET_HELLO_size (hello));
+    GNUNET_memcpy (ret->hello,
+                  hello,
+                  GNUNET_HELLO_size (hello));
   }
   GNUNET_break (GNUNET_OK ==
-                GNUNET_CONTAINER_multipeermap_put (peers, peer,
+                GNUNET_CONTAINER_multipeermap_put (peers,
+                                                   peer,
                                                    ret,
                                                    GNUNET_CONTAINER_MULTIHASHMAPOPTION_UNIQUE_ONLY));
   return ret;
@@ -529,25 +402,15 @@ setup_filter (struct Peer *peer)
       GNUNET_TIME_relative_to_absolute
       (HELLO_ADVERTISEMENT_MIN_REPEAT_FREQUENCY);
   /* never send a peer its own HELLO */
-  GNUNET_CRYPTO_hash (&peer->pid, sizeof (struct GNUNET_PeerIdentity), &hc);
+  GNUNET_CRYPTO_hash (&peer->pid,
+                      sizeof (struct GNUNET_PeerIdentity),
+                      &hc);
   GNUNET_CONTAINER_bloomfilter_add (peer->filter, &hc);
 }
 
 
 /**
- * Function to fill send buffer with HELLO.
- *
- * @param cls 'struct Peer' of the target peer
- * @param size number of bytes available in @a buf
- * @param buf where the callee should write the message
- * @return number of bytes written to @a buf
- */
-static size_t
-hello_advertising_ready (void *cls, size_t size, void *buf);
-
-
-/**
- * Closure for 'find_advertisable_hello'.
+ * Closure for #find_advertisable_hello().
  */
 struct FindAdvHelloContext
 {
@@ -577,10 +440,12 @@ struct FindAdvHelloContext
  * @param cls closure
  * @param pid identity of a peer
  * @param value 'struct Peer*' for the peer we are considering
- * @return GNUNET_YES (continue iteration)
+ * @return #GNUNET_YES (continue iteration)
  */
 static int
-find_advertisable_hello (void *cls, const struct GNUNET_PeerIdentity * pid, void *value)
+find_advertisable_hello (void *cls,
+                         const struct GNUNET_PeerIdentity *pid,
+                         void *value)
 {
   struct FindAdvHelloContext *fah = cls;
   struct Peer *pos = value;
@@ -603,7 +468,8 @@ find_advertisable_hello (void *cls, const struct GNUNET_PeerIdentity * pid, void
   hs = GNUNET_HELLO_size (pos->hello);
   if (hs > fah->max_size)
     return GNUNET_YES;
-  GNUNET_CRYPTO_hash (&fah->peer->pid, sizeof (struct GNUNET_PeerIdentity), &hc);
+  GNUNET_CRYPTO_hash (&fah->peer->pid,
+                     sizeof (struct GNUNET_PeerIdentity), &hc);
   if (GNUNET_NO ==
       GNUNET_CONTAINER_bloomfilter_test (pos->filter,
                                          &hc))
@@ -617,44 +483,64 @@ find_advertisable_hello (void *cls, const struct GNUNET_PeerIdentity * pid, void
  * peer and ask for it.
  *
  * @param cls for which peer to schedule the HELLO
- * @param tc task context
  */
 static void
-schedule_next_hello (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
+schedule_next_hello (void *cls)
 {
   struct Peer *pl = cls;
   struct FindAdvHelloContext fah;
-  size_t next_want;
+  struct GNUNET_MQ_Envelope *env;
+  size_t want;
   struct GNUNET_TIME_Relative delay;
+  struct GNUNET_HashCode hc;
 
-  pl->hello_delay_task = GNUNET_SCHEDULER_NO_TASK;
-  GNUNET_assert (GNUNET_YES == pl->is_connected);
-  if (0 != (tc->reason & GNUNET_SCHEDULER_REASON_SHUTDOWN))
-    return;                     /* we're out of here */
-  if (pl->hello_req != NULL)
-    return;                     /* did not finish sending the previous one */
+  pl->hello_delay_task = NULL;
+  GNUNET_assert (NULL != pl->mq);
   /* find applicable HELLOs */
   fah.peer = pl;
   fah.result = NULL;
   fah.max_size = GNUNET_SERVER_MAX_MESSAGE_SIZE - 1;
   fah.next_adv = GNUNET_TIME_UNIT_FOREVER_REL;
-  GNUNET_CONTAINER_multipeermap_iterate (peers, &find_advertisable_hello, &fah);
+  GNUNET_CONTAINER_multipeermap_iterate (peers,
+                                         &find_advertisable_hello,
+                                         &fah);
   pl->hello_delay_task =
-      GNUNET_SCHEDULER_add_delayed (fah.next_adv, &schedule_next_hello, pl);
-  if (fah.result == NULL)
+      GNUNET_SCHEDULER_add_delayed (fah.next_adv,
+                                    &schedule_next_hello,
+                                    pl);
+  if (NULL == fah.result)
     return;
-  next_want = GNUNET_HELLO_size (fah.result->hello);
   delay = GNUNET_TIME_absolute_get_remaining (pl->next_hello_allowed);
-  if (0 == delay.rel_value_us)
-  {
-    /* now! */
-    pl->hello_req =
-        GNUNET_CORE_notify_transmit_ready (handle, GNUNET_YES,
-                                           GNUNET_CORE_PRIO_BEST_EFFORT,
-                                           GNUNET_CONSTANTS_SERVICE_TIMEOUT,
-                                           &pl->pid, next_want,
-                                           &hello_advertising_ready, pl);
-  }
+  if (0 != delay.rel_value_us)
+    return;
+
+  want = GNUNET_HELLO_size (fah.result->hello);
+  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+             "Sending HELLO with %u bytes",
+             (unsigned int) want);
+  env = GNUNET_MQ_msg_copy (&fah.result->hello->header);
+  GNUNET_MQ_send (pl->mq,
+                 env);
+
+  /* avoid sending this one again soon */
+  GNUNET_CRYPTO_hash (&pl->pid,
+                     sizeof (struct GNUNET_PeerIdentity),
+                     &hc);
+  GNUNET_CONTAINER_bloomfilter_add (fah.result->filter,
+                                   &hc);
+
+  GNUNET_STATISTICS_update (stats,
+                           gettext_noop ("# HELLO messages gossipped"),
+                           1,
+                           GNUNET_NO);
+  /* prepare to send the next one */
+  pl->next_hello_allowed
+    = GNUNET_TIME_relative_to_absolute (HELLO_ADVERTISEMENT_MIN_FREQUENCY);
+  if (NULL != pl->hello_delay_task)
+    GNUNET_SCHEDULER_cancel (pl->hello_delay_task);
+  pl->hello_delay_task
+    = GNUNET_SCHEDULER_add_now (&schedule_next_hello,
+                               pl);
 }
 
 
@@ -663,30 +549,27 @@ schedule_next_hello (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
  * and recalculate when we should send HELLOs to it based
  * on our current state (something changed!).
  *
- * @param cls closure, 'struct Peer' to skip, or NULL
+ * @param cls closure `struct Peer` to skip, or NULL
  * @param pid identity of a peer
- * @param value 'struct Peer*' for the peer
- * @return GNUNET_YES (always)
+ * @param value `struct Peer *` for the peer
+ * @return #GNUNET_YES (always)
  */
 static int
-reschedule_hellos (void *cls, const struct GNUNET_PeerIdentity * pid, void *value)
+reschedule_hellos (void *cls,
+                   const struct GNUNET_PeerIdentity *pid,
+                   void *value)
 {
   struct Peer *peer = value;
   struct Peer *skip = cls;
 
   if (skip == peer)
     return GNUNET_YES;
-  if (!peer->is_connected)
+  if (NULL == peer->mq)
     return GNUNET_YES;
-  if (peer->hello_req != NULL)
-  {
-    GNUNET_CORE_notify_transmit_ready_cancel (peer->hello_req);
-    peer->hello_req = NULL;
-  }
-  if (peer->hello_delay_task != GNUNET_SCHEDULER_NO_TASK)
+  if (NULL != peer->hello_delay_task)
   {
     GNUNET_SCHEDULER_cancel (peer->hello_delay_task);
-    peer->hello_delay_task = GNUNET_SCHEDULER_NO_TASK;
+    peer->hello_delay_task = NULL;
   }
   peer->hello_delay_task =
       GNUNET_SCHEDULER_add_now (&schedule_next_hello, peer);
@@ -699,44 +582,64 @@ reschedule_hellos (void *cls, const struct GNUNET_PeerIdentity * pid, void *valu
  *
  * @param cls closure
  * @param peer peer identity this notification is about
+ * @param mq message queue for communicating with @a peer
+ * @return our `struct Peer` for @a peer
  */
-static void
-connect_notify (void *cls, const struct GNUNET_PeerIdentity *peer)
+static void *
+connect_notify (void *cls,
+                const struct GNUNET_PeerIdentity *peer,
+               struct GNUNET_MQ_Handle *mq)
 {
   struct Peer *pos;
+  uint64_t flags;
+  const void *extra;
 
   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
               "Core told us that we are connecting to `%s'\n",
               GNUNET_i2s (peer));
-  if (0 == memcmp (&my_identity, peer, sizeof (struct GNUNET_PeerIdentity)))
-    return;
-
+  if (0 == memcmp (&my_identity,
+                   peer,
+                   sizeof (struct GNUNET_PeerIdentity)))
+    return NULL;
+  extra = GNUNET_CORE_get_mq_options (GNUNET_YES,
+                                     GNUNET_CORE_PRIO_BEST_EFFORT,
+                                     &flags);
+  GNUNET_MQ_set_options (mq,
+                        flags,
+                        extra);
   connection_count++;
-  GNUNET_STATISTICS_set (stats, gettext_noop ("# peers connected"),
-                         connection_count, GNUNET_NO);
-  pos = GNUNET_CONTAINER_multipeermap_get (peers, peer);
+  GNUNET_STATISTICS_set (stats,
+                         gettext_noop ("# peers connected"),
+                         connection_count,
+                         GNUNET_NO);
+  pos = GNUNET_CONTAINER_multipeermap_get (peers,
+                                           peer);
   if (NULL == pos)
   {
-    pos = make_peer (peer, NULL, GNUNET_NO);
-    GNUNET_break (GNUNET_OK == is_connection_allowed (pos));
+    pos = make_peer (peer,
+                     NULL,
+                     GNUNET_NO);
   }
   else
   {
-    GNUNET_assert (GNUNET_NO == pos->is_connected);
-    pos->greylisted_until.abs_value_us = 0;        /* remove greylisting */
+    GNUNET_assert (NULL == pos->mq);
   }
-  pos->is_connected = GNUNET_YES;
-  pos->connect_attempts = 0;    /* re-set back-off factor */
+  pos->mq = mq;
   if (pos->is_friend)
   {
-    if ((friend_count == minimum_friend_count - 1) &&
-        (GNUNET_YES != friends_only))
-      whitelist_peers ();
     friend_count++;
-    GNUNET_STATISTICS_set (stats, gettext_noop ("# friends connected"),
-                           friend_count, GNUNET_NO);
+    if ( (friend_count == minimum_friend_count) &&
+         (GNUNET_YES != friends_only) )
+      whitelist_peers ();
+    GNUNET_STATISTICS_set (stats,
+                           gettext_noop ("# friends connected"),
+                           friend_count,
+                           GNUNET_NO);
   }
-  reschedule_hellos (NULL, peer, pos);
+  reschedule_hellos (NULL,
+                     peer,
+                     pos);
+  return pos;
 }
 
 
@@ -745,15 +648,17 @@ connect_notify (void *cls, const struct GNUNET_PeerIdentity *peer)
  *
  * @param cls closure, not used
  * @param pid identity of a peer
- * @param value 'struct Peer*' for the peer
- * @return GNUNET_YES (continue to iterate)
+ * @param value `struct Peer *` for the peer
+ * @return #GNUNET_YES (continue to iterate)
  */
 static int
-try_add_peers (void *cls, const struct GNUNET_PeerIdentity * pid, void *value)
+try_add_peers (void *cls,
+               const struct GNUNET_PeerIdentity *pid,
+               void *value)
 {
   struct Peer *pos = value;
 
-  schedule_attempt_connect (pos);
+  attempt_connect (pos);
   return GNUNET_YES;
 }
 
@@ -762,14 +667,15 @@ try_add_peers (void *cls, const struct GNUNET_PeerIdentity * pid, void *value)
  * Add peers and schedule connection attempt
  *
  * @param cls unused, NULL
- * @param tc scheduler context
  */
 static void
-add_peer_task (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
+add_peer_task (void *cls)
 {
-  add_task = GNUNET_SCHEDULER_NO_TASK;
+  add_task = NULL;
 
-  GNUNET_CONTAINER_multipeermap_iterate (peers, &try_add_peers, NULL);
+  GNUNET_CONTAINER_multipeermap_iterate (peers,
+                                         &try_add_peers,
+                                         NULL);
 }
 
 
@@ -778,54 +684,54 @@ add_peer_task (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
  *
  * @param cls closure
  * @param peer peer identity this notification is about
+ * @param internal_cls the `struct Peer` for this peer
  */
 static void
-disconnect_notify (void *cls, const struct GNUNET_PeerIdentity *peer)
+disconnect_notify (void *cls,
+                   const struct GNUNET_PeerIdentity *peer,
+                  void *internal_cls)
 {
-  struct Peer *pos;
+  struct Peer *pos = internal_cls;
 
-  if (0 == memcmp (&my_identity, peer, sizeof (struct GNUNET_PeerIdentity)))
-    return;
+  if (NULL == pos)
+    return; /* myself, we're shutting down */
   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
               "Core told us that we disconnected from `%s'\n",
               GNUNET_i2s (peer));
-  pos = GNUNET_CONTAINER_multipeermap_get (peers, peer);
-  if (NULL == pos)
+  if (NULL == pos->mq)
   {
     GNUNET_break (0);
     return;
   }
-  if (pos->is_connected != GNUNET_YES)
-  {
-    GNUNET_break (0);
-    return;
-  }
-  pos->is_connected = GNUNET_NO;
+  pos->mq = NULL;
   connection_count--;
-  if (NULL != pos->hello_req)
-  {
-    GNUNET_CORE_notify_transmit_ready_cancel (pos->hello_req);
-    pos->hello_req = NULL;
-  }
-  if (GNUNET_SCHEDULER_NO_TASK != pos->hello_delay_task)
+  if (NULL != pos->hello_delay_task)
   {
     GNUNET_SCHEDULER_cancel (pos->hello_delay_task);
-    pos->hello_delay_task = GNUNET_SCHEDULER_NO_TASK;
+    pos->hello_delay_task = NULL;
   }
-  GNUNET_STATISTICS_set (stats, gettext_noop ("# peers connected"),
-                         connection_count, GNUNET_NO);
+  GNUNET_STATISTICS_set (stats,
+                         gettext_noop ("# peers connected"),
+                         connection_count,
+                         GNUNET_NO);
   if (pos->is_friend)
   {
     friend_count--;
-    GNUNET_STATISTICS_set (stats, gettext_noop ("# friends connected"),
-                           friend_count, GNUNET_NO);
+    GNUNET_STATISTICS_set (stats,
+                           gettext_noop ("# friends connected"),
+                           friend_count,
+                           GNUNET_NO);
   }
-  if (((connection_count < target_connection_count) ||
-       (friend_count < minimum_friend_count)) &&
-      (GNUNET_SCHEDULER_NO_TASK == add_task))
-    add_task = GNUNET_SCHEDULER_add_now (&add_peer_task, NULL);
-  if ((friend_count < minimum_friend_count) && (blacklist == NULL))
-    blacklist = GNUNET_TRANSPORT_blacklist (cfg, &blacklist_check, NULL);
+  if ( ( (connection_count < target_connection_count) ||
+         (friend_count < minimum_friend_count)) &&
+       (NULL == add_task) )
+    add_task = GNUNET_SCHEDULER_add_now (&add_peer_task,
+                                         NULL);
+  if ( (friend_count < minimum_friend_count) &&
+       (NULL == blacklist))
+    blacklist = GNUNET_TRANSPORT_blacklist (cfg,
+                                            &blacklist_check,
+                                            NULL);
 }
 
 
@@ -835,10 +741,11 @@ disconnect_notify (void *cls, const struct GNUNET_PeerIdentity *peer)
  * @param cls flag that we will set if we see any addresses
  * @param address the address of the peer
  * @param expiration when will the given address expire
- * @return GNUNET_SYSERR always, to terminate iteration
+ * @return #GNUNET_SYSERR always, to terminate iteration
  */
 static int
-address_iterator (void *cls, const struct GNUNET_HELLO_Address *address,
+address_iterator (void *cls,
+                  const struct GNUNET_HELLO_Address *address,
                   struct GNUNET_TIME_Absolute expiration)
 {
   int *flag = cls;
@@ -869,30 +776,39 @@ consider_for_advertising (const struct GNUNET_HELLO_Message *hello)
     GNUNET_break (0);
     return;
   }
-  if (0 == memcmp (&pid, &my_identity, sizeof (struct GNUNET_PeerIdentity)))
+  if (0 == memcmp (&pid,
+                   &my_identity,
+                   sizeof (struct GNUNET_PeerIdentity)))
     return;                     /* that's me! */
   have_address = GNUNET_NO;
-  GNUNET_HELLO_iterate_addresses (hello, GNUNET_NO, &address_iterator,
+  GNUNET_HELLO_iterate_addresses (hello,
+                                  GNUNET_NO,
+                                  &address_iterator,
                                   &have_address);
   if (GNUNET_NO == have_address)
     return;                     /* no point in advertising this one... */
   peer = GNUNET_CONTAINER_multipeermap_get (peers, &pid);
   if (NULL == peer)
   {
-    peer = make_peer (&pid, hello, GNUNET_NO);
+    peer = make_peer (&pid,
+                      hello,
+                      GNUNET_NO);
   }
-  else if (peer->hello != NULL)
+  else if (NULL != peer->hello)
   {
-    dt = GNUNET_HELLO_equals (peer->hello, hello, GNUNET_TIME_absolute_get ());
+    dt = GNUNET_HELLO_equals (peer->hello,
+                              hello,
+                              GNUNET_TIME_absolute_get ());
     if (dt.abs_value_us == GNUNET_TIME_UNIT_FOREVER_ABS.abs_value_us)
       return;                   /* nothing new here */
   }
   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
-              "Found `%s' from peer `%s' for advertising\n", "HELLO",
+              "Found HELLO from peer `%s' for advertising\n",
               GNUNET_i2s (&pid));
-  if (peer->hello != NULL)
+  if (NULL != peer->hello)
   {
-    nh = GNUNET_HELLO_merge (peer->hello, hello);
+    nh = GNUNET_HELLO_merge (peer->hello,
+                             hello);
     GNUNET_free (peer->hello);
     peer->hello = nh;
   }
@@ -900,14 +816,21 @@ consider_for_advertising (const struct GNUNET_HELLO_Message *hello)
   {
     size = GNUNET_HELLO_size (hello);
     peer->hello = GNUNET_malloc (size);
-    memcpy (peer->hello, hello, size);
+    GNUNET_memcpy (peer->hello,
+            hello,
+            size);
   }
-  if (peer->filter != NULL)
+  if (NULL != peer->filter)
+  {
     GNUNET_CONTAINER_bloomfilter_free (peer->filter);
+    peer->filter = NULL;
+  }
   setup_filter (peer);
   /* since we have a new HELLO to pick from, re-schedule all
    * HELLO requests that are not bound by the HELLO send rate! */
-  GNUNET_CONTAINER_multipeermap_iterate (peers, &reschedule_hellos, peer);
+  GNUNET_CONTAINER_multipeermap_iterate (peers,
+                                         &reschedule_hellos,
+                                         peer);
 }
 
 
@@ -921,64 +844,60 @@ consider_for_advertising (const struct GNUNET_HELLO_Message *hello)
  * @param err_msg NULL if successful, otherwise contains error message
  */
 static void
-process_peer (void *cls, const struct GNUNET_PeerIdentity *peer,
-              const struct GNUNET_HELLO_Message *hello, const char *err_msg)
+process_peer (void *cls,
+              const struct GNUNET_PeerIdentity *peer,
+              const struct GNUNET_HELLO_Message *hello,
+              const char *err_msg)
 {
   struct Peer *pos;
 
-  if (err_msg != NULL)
+  if (NULL != err_msg)
   {
     GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
                 _("Error in communication with PEERINFO service: %s\n"),
                 err_msg);
     GNUNET_PEERINFO_notify_cancel (peerinfo_notify);
-    peerinfo_notify = GNUNET_PEERINFO_notify (cfg, GNUNET_NO, &process_peer, NULL);
+    peerinfo_notify = GNUNET_PEERINFO_notify (cfg,
+                                              GNUNET_NO,
+                                              &process_peer,
+                                              NULL);
     return;
   }
-  GNUNET_assert (peer != NULL);
-  if (0 == memcmp (&my_identity, peer, sizeof (struct GNUNET_PeerIdentity)))
+  GNUNET_assert (NULL != peer);
+  if (0 == memcmp (&my_identity,
+                   peer,
+                   sizeof (struct GNUNET_PeerIdentity)))
     return;                     /* that's me! */
-  if (hello == NULL)
+  if (NULL == hello)
   {
     /* free existing HELLO, if any */
-    pos = GNUNET_CONTAINER_multipeermap_get (peers, peer);
+    pos = GNUNET_CONTAINER_multipeermap_get (peers,
+                                             peer);
     if (NULL != pos)
     {
       GNUNET_free_non_null (pos->hello);
       pos->hello = NULL;
-      if (pos->filter != NULL)
+      if (NULL != pos->filter)
       {
         GNUNET_CONTAINER_bloomfilter_free (pos->filter);
         pos->filter = NULL;
       }
-      if ((GNUNET_NO == pos->is_connected) && (GNUNET_NO == pos->is_friend) &&
-          (0 ==
-           GNUNET_TIME_absolute_get_remaining (pos->
-                                               greylisted_until).rel_value_us))
-        free_peer (NULL, &pos->pid, pos);
+      if ( (NULL == pos->mq) &&
+           (GNUNET_NO == pos->is_friend) )
+        free_peer (NULL,
+                   &pos->pid,
+                   pos);
     }
     return;
   }
   consider_for_advertising (hello);
-  pos = GNUNET_CONTAINER_multipeermap_get (peers, peer);
-  if (pos == NULL)
-    pos = make_peer (peer, hello, GNUNET_NO);
-  GNUNET_assert (NULL != pos);
-  if (GNUNET_YES == pos->is_connected)
-  {
-    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Already connected to peer `%s'\n",
-                GNUNET_i2s (peer));
-    return;
-  }
-  if (GNUNET_TIME_absolute_get_remaining (pos->greylisted_until).rel_value_us > 0)
-  {
-    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Already tried peer `%s' recently\n",
-                GNUNET_i2s (peer));
-    return;                     /* peer still greylisted */
-  }
-  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Considering connecting to peer `%s'\n",
-              GNUNET_i2s (peer));
-  schedule_attempt_connect (pos);
+  pos = GNUNET_CONTAINER_multipeermap_get (peers,
+                                           peer);
+  if (NULL == pos)
+    pos = make_peer (peer,
+                     hello,
+                     GNUNET_NO);
+  attempt_connect (pos);
 }
 
 
@@ -996,8 +915,7 @@ core_init (void *cls,
   if (NULL == my_id)
   {
     GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
-                _
-                ("Failed to connect to core service, can not manage topology!\n"));
+                _("Failed to connect to core service, can not manage topology!\n"));
     GNUNET_SCHEDULER_shutdown ();
     return;
   }
@@ -1005,8 +923,10 @@ core_init (void *cls,
   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
              "I am peer `%s'\n",
              GNUNET_i2s (my_id));
-  peerinfo_notify = GNUNET_PEERINFO_notify (cfg, GNUNET_NO,
-                                           &process_peer, NULL);
+  peerinfo_notify = GNUNET_PEERINFO_notify (cfg,
+                                            GNUNET_NO,
+                                           &process_peer,
+                                            NULL);
 }
 
 
@@ -1023,7 +943,9 @@ handle_friend (void *cls,
   unsigned int *entries_found = cls;
   struct Peer *fl;
 
-  if (0 == memcmp (pid, &my_identity, sizeof (struct GNUNET_PeerIdentity)))
+  if (0 == memcmp (pid,
+                   &my_identity,
+                   sizeof (struct GNUNET_PeerIdentity)))
   {
     GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
                 _("Found myself `%s' in friend list (useless, ignored)\n"),
@@ -1052,19 +974,23 @@ read_friends_file (const struct GNUNET_CONFIGURATION_Handle *cfg)
                             &handle_friend,
                             &entries_found))
   {
-    if ((friends_only) || (minimum_friend_count > 0))
+    if ( (GNUNET_YES == friends_only) ||
+         (minimum_friend_count > 0))
       GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
                   _("Encountered errors parsing friends list!\n"));
   }
-  GNUNET_STATISTICS_update (stats, gettext_noop ("# friends in configuration"),
-                            entries_found, GNUNET_NO);
-  if ((minimum_friend_count > entries_found) && (friends_only == GNUNET_NO))
+  GNUNET_STATISTICS_update (stats,
+                            gettext_noop ("# friends in configuration"),
+                            entries_found,
+                            GNUNET_NO);
+  if ( (minimum_friend_count > entries_found) &&
+       (GNUNET_NO == friends_only) )
   {
     GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
                 _("Fewer friends specified than required by minimum friend count. Will only connect to friends.\n"));
   }
-  if ((minimum_friend_count > target_connection_count) &&
-      (friends_only == GNUNET_NO))
+  if ( (minimum_friend_count > target_connection_count) &&
+       (GNUNET_NO == friends_only))
   {
     GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
                 _("More friendly connections required than target total number of connections.\n"));
@@ -1072,99 +998,90 @@ read_friends_file (const struct GNUNET_CONFIGURATION_Handle *cfg)
 }
 
 
+/**
+ * Hello offer complete. Clean up.
+ */
+static void
+done_offer_hello (void *cls)
+{
+  oh = NULL;
+}
+
+
 /**
  * This function is called whenever an encrypted HELLO message is
  * received.
  *
- * @param cls closure
- * @param other the other peer involved (sender or receiver, NULL
- *        for loopback messages where we are both sender and receiver)
+ * @param cls closure with the peer identity of the sender
  * @param message the actual HELLO message
- * @return GNUNET_OK to keep the connection open,
- *         GNUNET_SYSERR to close it (signal serious error)
+ * @return #GNUNET_OK if @a message is well-formed
+ *         #GNUNET_SYSERR if @a message is invalid
  */
 static int
-handle_encrypted_hello (void *cls, const struct GNUNET_PeerIdentity *other,
-                        const struct GNUNET_MessageHeader *message)
+check_hello (void *cls,
+            const struct GNUNET_HELLO_Message *message)
 {
-  struct Peer *peer;
   struct GNUNET_PeerIdentity pid;
 
-  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Received encrypted `%s' from peer `%s'",
-              "HELLO", GNUNET_i2s (other));
   if (GNUNET_OK !=
-      GNUNET_HELLO_get_id ((const struct GNUNET_HELLO_Message *) message, &pid))
+      GNUNET_HELLO_get_id (message,
+                          &pid))
   {
     GNUNET_break_op (0);
     return GNUNET_SYSERR;
   }
-  GNUNET_STATISTICS_update (stats, gettext_noop ("# HELLO messages received"),
-                            1, GNUNET_NO);
-  peer = GNUNET_CONTAINER_multipeermap_get (peers, &pid);
-  if (NULL == peer)
-  {
-    if ((GNUNET_YES == friends_only) || (friend_count < minimum_friend_count))
-      return GNUNET_OK;
-  }
-  else
-  {
-    if ((GNUNET_YES != peer->is_friend) && (GNUNET_YES == friends_only))
-      return GNUNET_OK;
-    if ((GNUNET_YES != peer->is_friend) &&
-        (friend_count < minimum_friend_count))
-      return GNUNET_OK;
-  }
-  if (transport != NULL)
-    GNUNET_TRANSPORT_offer_hello (transport, message, NULL, NULL);
   return GNUNET_OK;
 }
 
 
 /**
- * Function to fill send buffer with HELLO.
+ * This function is called whenever an encrypted HELLO message is
+ * received.
  *
- * @param cls 'struct Peer' of the target peer
- * @param size number of bytes available in buf
- * @param buf where the callee should write the message
- * @return number of bytes written to buf
+ * @param cls closure with the peer identity of the sender
+ * @param message the actual HELLO message
  */
-static size_t
-hello_advertising_ready (void *cls, size_t size, void *buf)
+static void
+handle_hello (void *cls,
+             const struct GNUNET_HELLO_Message *message)
 {
-  struct Peer *pl = cls;
-  struct FindAdvHelloContext fah;
-  size_t want;
-  struct GNUNET_HashCode hc;
+  const struct GNUNET_PeerIdentity *other = cls;
+  struct Peer *peer;
+  struct GNUNET_PeerIdentity pid;
 
-  pl->hello_req = NULL;
-  GNUNET_assert (GNUNET_YES == pl->is_connected);
-  /* find applicable HELLOs */
-  fah.peer = pl;
-  fah.result = NULL;
-  fah.max_size = size;
-  fah.next_adv = GNUNET_TIME_UNIT_FOREVER_REL;
-  GNUNET_CONTAINER_multipeermap_iterate (peers, &find_advertisable_hello, &fah);
-  want = 0;
-  if (fah.result != NULL)
+  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+              "Received encrypted HELLO from peer `%s'",
+              GNUNET_i2s (other));
+  GNUNET_assert (GNUNET_OK ==
+                GNUNET_HELLO_get_id (message,
+                                     &pid));
+  GNUNET_STATISTICS_update (stats,
+                            gettext_noop ("# HELLO messages received"),
+                            1,
+                            GNUNET_NO);
+  peer = GNUNET_CONTAINER_multipeermap_get (peers,
+                                           &pid);
+  if (NULL == peer)
   {
-    want = GNUNET_HELLO_size (fah.result->hello);
-    GNUNET_assert (want <= size);
-    memcpy (buf, fah.result->hello, want);
-    GNUNET_CRYPTO_hash (&pl->pid, sizeof (struct GNUNET_PeerIdentity), &hc);
-    GNUNET_CONTAINER_bloomfilter_add (fah.result->filter, &hc);
-    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Sending `%s' with %u bytes", "HELLO",
-                (unsigned int) want);
-    GNUNET_STATISTICS_update (stats,
-                              gettext_noop ("# HELLO messages gossipped"), 1,
-                              GNUNET_NO);
+    if ( (GNUNET_YES == friends_only) ||
+         (friend_count < minimum_friend_count) )
+      return;
   }
-
-  if (pl->hello_delay_task != GNUNET_SCHEDULER_NO_TASK)
-    GNUNET_SCHEDULER_cancel (pl->hello_delay_task);
-  pl->next_hello_allowed =
-      GNUNET_TIME_relative_to_absolute (HELLO_ADVERTISEMENT_MIN_FREQUENCY);
-  pl->hello_delay_task = GNUNET_SCHEDULER_add_now (&schedule_next_hello, pl);
-  return want;
+  else
+  {
+    if ( (GNUNET_YES != peer->is_friend) &&
+         (GNUNET_YES == friends_only) )
+      return;
+    if ((GNUNET_YES != peer->is_friend) &&
+        (friend_count < minimum_friend_count))
+      return;
+  }
+  if (NULL != oh)
+    GNUNET_TRANSPORT_offer_hello_cancel (oh);
+  oh = GNUNET_TRANSPORT_offer_hello (cfg,
+                                     &message->header,
+                                     &done_offer_hello,
+                                     NULL);
 }
 
 
@@ -1173,33 +1090,42 @@ hello_advertising_ready (void *cls, size_t size, void *buf)
  * the transport and core.
  *
  * @param cls unused, NULL
- * @param tc scheduler context
  */
 static void
-cleaning_task (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
+cleaning_task (void *cls)
 {
   if (NULL != peerinfo_notify)
   {
     GNUNET_PEERINFO_notify_cancel (peerinfo_notify);
     peerinfo_notify = NULL;
   }
-  GNUNET_TRANSPORT_disconnect (transport);
-  transport = NULL;
-  if (handle != NULL)
+  if (NULL != handle)
   {
     GNUNET_CORE_disconnect (handle);
     handle = NULL;
   }
   whitelist_peers ();
-  if (GNUNET_SCHEDULER_NO_TASK != add_task)
+  if (NULL != add_task)
   {
     GNUNET_SCHEDULER_cancel (add_task);
-    add_task = GNUNET_SCHEDULER_NO_TASK;
+    add_task = NULL;
+  }
+  if (NULL != oh)
+  {
+    GNUNET_TRANSPORT_offer_hello_cancel (oh);
+    oh = NULL;
   }
-  GNUNET_CONTAINER_multipeermap_iterate (peers, &free_peer, NULL);
+  GNUNET_CONTAINER_multipeermap_iterate (peers,
+                                         &free_peer,
+                                         NULL);
   GNUNET_CONTAINER_multipeermap_destroy (peers);
   peers = NULL;
-  if (stats != NULL)
+  if (NULL != ats)
+  {
+    GNUNET_ATS_connectivity_done (ats);
+    ats = NULL;
+  }
+  if (NULL != stats)
   {
     GNUNET_STATISTICS_destroy (stats, GNUNET_NO);
     stats = NULL;
@@ -1221,57 +1147,61 @@ run (void *cls,
      const char *cfgfile,
      const struct GNUNET_CONFIGURATION_Handle *c)
 {
-  static struct GNUNET_CORE_MessageHandler handlers[] = {
-    {&handle_encrypted_hello, GNUNET_MESSAGE_TYPE_HELLO, 0},
-    {NULL, 0, 0}
+  struct GNUNET_MQ_MessageHandler handlers[] = {
+    GNUNET_MQ_hd_var_size (hello,
+                           GNUNET_MESSAGE_TYPE_HELLO,
+                           struct GNUNET_HELLO_Message,
+                           NULL),
+    GNUNET_MQ_handler_end ()
   };
   unsigned long long opt;
 
   cfg = c;
   stats = GNUNET_STATISTICS_create ("topology", cfg);
   friends_only =
-      GNUNET_CONFIGURATION_get_value_yesno (cfg, "TOPOLOGY", "FRIENDS-ONLY");
+      GNUNET_CONFIGURATION_get_value_yesno (cfg,
+                                            "TOPOLOGY",
+                                            "FRIENDS-ONLY");
   if (GNUNET_OK !=
-      GNUNET_CONFIGURATION_get_value_number (cfg, "TOPOLOGY", "MINIMUM-FRIENDS",
+      GNUNET_CONFIGURATION_get_value_number (cfg,
+                                             "TOPOLOGY",
+                                             "MINIMUM-FRIENDS",
                                              &opt))
     opt = 0;
   minimum_friend_count = (unsigned int) opt;
   if (GNUNET_OK !=
-      GNUNET_CONFIGURATION_get_value_number (cfg, "TOPOLOGY",
-                                             "TARGET-CONNECTION-COUNT", &opt))
+      GNUNET_CONFIGURATION_get_value_number (cfg,
+                                             "TOPOLOGY",
+                                             "TARGET-CONNECTION-COUNT",
+                                             &opt))
     opt = 16;
   target_connection_count = (unsigned int) opt;
-  peers = GNUNET_CONTAINER_multipeermap_create (target_connection_count * 2, GNUNET_NO);
-
-  if ((friends_only == GNUNET_YES) || (minimum_friend_count > 0))
-    read_friends_file (cfg);
+  peers = GNUNET_CONTAINER_multipeermap_create (target_connection_count * 2,
+                                                GNUNET_NO);
+  read_friends_file (cfg);
   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
               "Topology would like %u connections with at least %u friends\n",
-              target_connection_count, minimum_friend_count);
-  if ((friend_count < minimum_friend_count) && (blacklist == NULL))
-    blacklist = GNUNET_TRANSPORT_blacklist (cfg, &blacklist_check, NULL);
-  transport = GNUNET_TRANSPORT_connect (cfg, NULL, NULL, NULL, NULL, NULL);
-  handle =
-      GNUNET_CORE_connect (cfg, NULL,
-                           &core_init,
-                           &connect_notify,
-                           &disconnect_notify,
-                           NULL, GNUNET_NO,
-                           NULL, GNUNET_NO,
-                           handlers);
-  GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_UNIT_FOREVER_REL, &cleaning_task,
-                                NULL);
-  if (NULL == transport)
-  {
-    GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
-                _("Failed to connect to `%s' service.\n"), "transport");
-    GNUNET_SCHEDULER_shutdown ();
-    return;
-  }
+              target_connection_count,
+              minimum_friend_count);
+  if ( (friend_count < minimum_friend_count) &&
+       (NULL == blacklist))
+    blacklist = GNUNET_TRANSPORT_blacklist (cfg,
+                                            &blacklist_check,
+                                            NULL);
+  ats = GNUNET_ATS_connectivity_init (cfg);
+  handle = GNUNET_CORE_connect (cfg,
+                               NULL,
+                               &core_init,
+                               &connect_notify,
+                               &disconnect_notify,
+                               handlers);
+  GNUNET_SCHEDULER_add_shutdown (&cleaning_task,
+                                NULL);
   if (NULL == handle)
   {
     GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
-                _("Failed to connect to `%s' service.\n"), "core");
+                _("Failed to connect to `%s' service.\n"),
+                "core");
     GNUNET_SCHEDULER_shutdown ();
     return;
   }
@@ -1298,22 +1228,23 @@ main (int argc, char *const *argv)
 
   ret =
       (GNUNET_OK ==
-       GNUNET_PROGRAM_run (argc, argv, "gnunet-daemon-topology",
-                           _
-                           ("GNUnet topology control (maintaining P2P cadet and F2F constraints)"),
+       GNUNET_PROGRAM_run (argc, argv,
+                           "gnunet-daemon-topology",
+                           _("GNUnet topology control"),
                            options, &run, NULL)) ? 0 : 1;
   GNUNET_free ((void*) argv);
   return ret;
 }
 
 
-#ifdef LINUX
+#if defined(LINUX) && defined(__GLIBC__)
 #include <malloc.h>
 
 /**
  * MINIMIZE heap size (way below 128k) since this process doesn't need much.
  */
-void __attribute__ ((constructor)) GNUNET_ARM_memory_init ()
+void __attribute__ ((constructor))
+GNUNET_ARM_memory_init ()
 {
   mallopt (M_TRIM_THRESHOLD, 4 * 1024);
   mallopt (M_TOP_PAD, 1 * 1024);