-add hold/drop logic

4 files changed, 111 insertions, 23 deletions

diff --git a/src/dht/gnunet-service-dht.c b/src/dht/gnunet-service-dht.c
index 35e219926..ae2ff6f7a 100644
--- a/src/dht/gnunet-service-dht.c
+++ b/src/dht/gnunet-service-dht.c
@@ -46,18 +46,18 @@
 /**
  * Information we keep per underlay.
  */
-struct Underlay
+struct GDS_Underlay
 {
 
   /**
    * Kept in a DLL.
    */
-  struct Underlay *next;
+  struct GDS_Underlay *next;
 
   /**
    * Kept in a DLL.
    */
-  struct Underlay *prev;
+  struct GDS_Underlay *prev;
 
   /**
    * Environment for this underlay.
@@ -109,7 +109,7 @@ struct MyAddress
   /**
    * Underlay of this address.
    */
-  struct Underlay *u;
+  struct GDS_Underlay *u;
 };
 
 
@@ -141,12 +141,12 @@ static struct GNUNET_SCHEDULER_Task *hello_task;
 /**
  * Handles for the DHT underlays.
  */
-static struct Underlay *u_head;
+static struct GDS_Underlay *u_head;
 
 /**
  * Handles for the DHT underlays.
  */
-static struct Underlay *u_tail;
+static struct GDS_Underlay *u_tail;
 
 /**
  * Head of addresses of this peer.
@@ -168,7 +168,7 @@ static double log_of_network_size_estimate;
 /**
  * Callback that is called when network size estimate is updated.
  *
- * @param cls a `struct Underlay`
+ * @param cls a `struct GDS_Underlay`
  * @param timestamp time when the estimate was received from the server (or created by the server)
  * @param logestimate the log(Base 2) value of the current network size estimate
  * @param std_dev standard deviation for the estimate
@@ -180,7 +180,7 @@ update_network_size_estimate (void *cls,
                               double logestimate,
                               double std_dev)
 {
-  struct Underlay *u = cls;
+  struct GDS_Underlay *u = cls;
   double sum = 0.0;
 
   GNUNET_STATISTICS_update (GDS_stats,
@@ -191,7 +191,7 @@ update_network_size_estimate (void *cls,
   u->network_size_estimate = pow (2.0,
                                   GNUNET_MAX (0.5,
                                               logestimate));
-  for (struct Underlay *p; NULL != p; p = p->next)
+  for (struct GDS_Underlay *p; NULL != p; p = p->next)
     sum += p->network_size_estimate;
   if (sum <= 2.0)
     log_of_network_size_estimate = 0.5;
@@ -257,7 +257,7 @@ u_address_add (void *cls,
                struct GNUNET_DHTU_Source *source,
                void **ctx)
 {
-  struct Underlay *u = cls;
+  struct GDS_Underlay *u = cls;
   struct MyAddress *a;
 
   a = GNUNET_new (struct MyAddress);
@@ -305,7 +305,7 @@ void
 GDS_u_try_connect (const struct GNUNET_PeerIdentity *pid,
                    const char *address)
 {
-  for (struct Underlay *u = u_head;
+  for (struct GDS_Underlay *u = u_head;
        NULL != u;
        u = u->next)
     u->dhtu->try_connect (u->dhtu->cls,
@@ -315,7 +315,7 @@ GDS_u_try_connect (const struct GNUNET_PeerIdentity *pid,
 
 
 void
-GDS_u_send (struct Underlay *u,
+GDS_u_send (struct GDS_Underlay *u,
             struct GNUNET_DHTU_Target *target,
             const void *msg,
             size_t msg_size,
@@ -331,6 +331,23 @@ GDS_u_send (struct Underlay *u,
 }
 
 
+void
+GDS_u_drop (struct GDS_Underlay *u,
+            struct GNUNET_DHTU_PreferenceHandle *ph)
+{
+  u->dhtu->drop (ph);
+}
+
+
+struct GNUNET_DHTU_PreferenceHandle *
+GDS_u_hold (struct GDS_Underlay *u,
+            struct GNUNET_DHTU_Target *target)
+{
+  return u->dhtu->hold (u->dhtu->cls,
+                        target);
+}
+
+
 /**
  * Task run during shutdown.
  *
@@ -370,7 +387,7 @@ static void
 load_underlay (void *cls,
                const char *section)
 {
-  struct Underlay *u;
+  struct GDS_Underlay *u;
   char *libname;
 
   (void) cls;
@@ -384,7 +401,7 @@ load_underlay (void *cls,
                                             "ENABLED"))
     return;
   section += strlen ("dhtu-");
-  u = GNUNET_new (struct Underlay);
+  u = GNUNET_new (struct GDS_Underlay);
   u->env.cls = u;
   u->env.address_add_cb = &u_address_add;
   u->env.address_del_cb = &u_address_del;
diff --git a/src/dht/gnunet-service-dht.h b/src/dht/gnunet-service-dht.h
index 403b3f5a1..d3bb39455 100644
--- a/src/dht/gnunet-service-dht.h
+++ b/src/dht/gnunet-service-dht.h
@@ -37,7 +37,7 @@
 /**
  * Information we keep per underlay.
  */
-struct Underlay;
+struct GDS_Underlay;
 
 /**
  * Configuration we use.
@@ -107,7 +107,7 @@ GDS_u_try_connect (const struct GNUNET_PeerIdentity *pid,
  * @param finished_cb_cls closure for @a finished_cb
  */
 void
-GDS_u_send (struct Underlay *u,
+GDS_u_send (struct GDS_Underlay *u,
             struct GNUNET_DHTU_Target *target,
             const void *msg,
             size_t msg_size,
@@ -116,6 +116,28 @@ GDS_u_send (struct Underlay *u,
 
 
 /**
+ * Drop a hold @a ph from underlay @a u.
+ *
+ * @param u the underlay controlling the hold
+ * @param ph the preference handle
+ */
+void
+GDS_u_drop (struct GDS_Underlay *u,
+            struct GNUNET_DHTU_PreferenceHandle *ph);
+
+
+/**
+ * Create a hold on @a target at underlay @a u.
+ *
+ * @param u the underlay controlling the target
+ * @param target the peer to hold the connection to
+ */
+struct GNUNET_DHTU_PreferenceHandle *
+GDS_u_hold (struct GDS_Underlay *u,
+            struct GNUNET_DHTU_Target *target);
+
+
+/**
  * Handle a reply we've received from another peer.  If the reply
  * matches any of our pending queries, forward it to the respective
  * client(s).
diff --git a/src/dht/gnunet-service-dht_neighbours.c b/src/dht/gnunet-service-dht_neighbours.c
index b7b5e8097..213308ca6 100644
--- a/src/dht/gnunet-service-dht_neighbours.c
+++ b/src/dht/gnunet-service-dht_neighbours.c
@@ -281,7 +281,7 @@ struct Target
   /**
    * Underlay providing this target.
    */
-  struct Underlay *u;
+  struct GDS_Underlay *u;
 
   /**
    * Peer this is a target for.
@@ -289,6 +289,11 @@ struct Target
   struct PeerInfo *pi;
 
   /**
+   * Handle used to 'hold' the connection to this peer.
+   */
+  struct GNUNET_DHTU_PreferenceHandle *ph;
+
+  /**
    * Set to number of messages are waiting for the transmission to finish.
    */
   unsigned int load;
@@ -686,15 +691,48 @@ send_find_peer_message (void *cls)
 }
 
 
+/**
+ * The list of the first #bucket_size peers of @a bucket
+ * changed. We should thus make sure we have called 'hold'
+ * all of the first bucket_size peers!
+ *
+ * @param[in,out] bucket the bucket where the peer set changed
+ */
+static void
+update_hold (struct PeerBucket *bucket)
+{
+  unsigned int off = 0;
+
+  /* find the peer -- we just go over all of them, should
+     be hardly any more expensive than just finding the 'right'
+     one. */
+  for (struct PeerInfo *pos = bucket->head;
+       NULL != pos;
+       pos = pos->next)
+  {
+    if (off > bucket_size)
+      break;   /* We only hold up to #bucket_size peers per bucket */
+    bucket_size++;
+    for (struct Target *tp = pos->t_head;
+         NULL != tp;
+         tp = tp->next)
+      if (NULL == tp->ph)
+        tp->ph = GDS_u_hold (tp->u,
+                             tp->utarget);
+  }
+}
+
+
 void
 GDS_u_connect (void *cls,
                struct GNUNET_DHTU_Target *target,
                const struct GNUNET_PeerIdentity *pid,
                void **ctx)
 {
-  struct Underlay *u = cls;
+  struct GDS_Underlay *u = cls;
   struct PeerInfo *pi;
   struct PeerBucket *bucket;
+  bool do_hold = false;
 
   /* Check for connect to self message */
   if (0 == GNUNET_memcmp (&GDS_my_identity,
@@ -734,7 +772,7 @@ GDS_u_connect (void *cls,
     if (bucket->peers_size <= bucket_size)
     {
       newly_found_peers++;
-      // FIXME: call 'hold'!
+      do_hold = true;
     }
     if ( (1 == GNUNET_CONTAINER_multipeermap_size (all_connected_peers)) &&
          (GNUNET_YES != disable_try_connect) )
@@ -758,6 +796,8 @@ GDS_u_connect (void *cls,
     *ctx = t;
 
   }
+  if (do_hold)
+    update_hold (bucket);
 }
 
 
@@ -767,6 +807,7 @@ GDS_u_disconnect (void *ctx)
   struct Target *t = ctx;
   struct PeerInfo *pi;
   struct PeerBucket *bucket;
+  bool was_held = false;
 
   /* Check for disconnect from self message (on shutdown) */
   if (NULL == t)
@@ -775,6 +816,13 @@ GDS_u_disconnect (void *ctx)
   GNUNET_CONTAINER_DLL_remove (pi->t_head,
                                pi->t_tail,
                                t);
+  if (NULL != t->ph)
+  {
+    GDS_u_drop (t->u,
+                t->ph);
+    t->ph = NULL;
+    was_held = true;
+  }
   if (t->load > 0)
   {
     t->dropped = true;
@@ -810,8 +858,9 @@ GDS_u_disconnect (void *ctx)
                                pi);
   GNUNET_assert (bucket->peers_size > 0);
   bucket->peers_size--;
-  // FIXME: check if this peer was in one of the first 'bucket_size'
-  // peers, and call 'hold' on the next peer if there is any!
+  if ( (was_held) &&
+       (bucket->peers_size >= bucket_size - 1) )
+    update_hold (bucket);
   while ( (closest_bucket > 0) &&
           (0 == k_buckets[closest_bucket - 1].peers_size))
     closest_bucket--;
@@ -2426,7 +2475,7 @@ GDS_u_receive (void *cls,
   };
   const struct GNUNET_MessageHeader *mh = message;
 
-  (void) cls; /* the 'struct Underlay' */
+  (void) cls; /* the 'struct GDS_Underlay' */
   (void) sctx; /* our receiver address */
   if (message_size < sizeof (*mh))
   {
diff --git a/src/dht/gnunet-service-dht_neighbours.h b/src/dht/gnunet-service-dht_neighbours.h
index 5a4c8c620..fecdbe9f1 100644
--- a/src/dht/gnunet-service-dht_neighbours.h
+++ b/src/dht/gnunet-service-dht_neighbours.h
@@ -136,7 +136,7 @@ GDS_am_closest_peer (const struct GNUNET_HashCode *key,
  * Function to call when we connect to a peer and can henceforth transmit to
  * that peer.
  *
- * @param cls the closure, must be a `struct Underlay`
+ * @param cls the closure, must be a `struct GDS_Underlay`
  * @param target handle to the target,
  *    pointer will remain valid until @e disconnect_cb is called
  * @para pid peer identity,