[GNUnet-SVN] r26415 - gnunet/src/dv

[gnunet]

Author: grothoff
Date: 2013-03-14 10:03:46 +0100 (Thu, 14 Mar 2013)
New Revision: 26415

Modified:
   gnunet/src/dv/gnunet-service-dv.c
Log:
-simplify design

Modified: gnunet/src/dv/gnunet-service-dv.c
===================================================================
--- gnunet/src/dv/gnunet-service-dv.c   2013-03-14 06:52:46 UTC (rev 26414)
+++ gnunet/src/dv/gnunet-service-dv.c   2013-03-14 09:03:46 UTC (rev 26415)
@@ -165,57 +165,17 @@
    * Transmit handle to core service.
    */
   struct GNUNET_CORE_TransmitHandle *cth;
-};
 
-
-/**
- * A route includes information about the next hop,
- * the target, and the ultimate distance to the
- * target.
- */
-struct Route
-{
-
   /**
-   * Which peer do we need to forward the message to?
-   */
-  struct DirectNeighbor *next_hop;
-
-  /**
-   * What would be the target, and how far is it away?
-   */
-  struct Target target;
-
-  /**
-   * Offset of this target in the respective consensus set.
-   */
-  unsigned int set_offset;
-
-};
-
-
-/**
- * Routing neighbors are neighbors that we exchange
- * routing information with; that is, their distance
- * must be strictly less than the DEFAULT_FISHEYE_DEPTH;
- * they can also be direct neighbors.
- */
-struct RoutingNeighbor
-{
-
-  /**
-   * Which peer is this, and how do we talk to it?
-   */
-  struct Route route;
-
-  /**
    * Routing table of the neighbor, NULL if not yet established.
+   * Keys are peer identities, values are 'struct Target' entries.
    */ 
   struct GNUNET_CONTAINER_MultiHashMap *neighbor_table;
 
   /**
    * Updated routing table of the neighbor, under construction,
    * NULL if we are not currently building it.
+   * Keys are peer identities, values are 'struct Target' entries.
    */ 
   struct GNUNET_CONTAINER_MultiHashMap *neighbor_table_consensus;
 
@@ -241,6 +201,32 @@
 
 
 /**
+ * A route includes information about the next hop,
+ * the target, and the ultimate distance to the
+ * target.
+ */
+struct Route
+{
+
+  /**
+   * Which peer do we need to forward the message to?
+   */
+  struct DirectNeighbor *next_hop;
+
+  /**
+   * What would be the target, and how far is it away?
+   */
+  struct Target target;
+
+  /**
+   * Offset of this target in the respective consensus set.
+   */
+  unsigned int set_offset;
+
+};
+
+
+/**
  * Set of targets we bring to a consensus; all targets in a set have a
  * distance equal to the sets distance (which is implied by the array
  * index of the set).
@@ -251,7 +237,7 @@
   /**
    * Array of targets in the set, may include NULL entries if a
    * neighbor has disconnected; the targets are allocated with the
-   * respective container (i.e. 'struct RoutingNeighbor'), not here.
+   * respective container (all_routes), not here.
    */
   struct Route **targets;
 
@@ -269,12 +255,6 @@
 static struct GNUNET_CONTAINER_MultiHashMap *direct_neighbors;
 
 /**
- * Hashmap of all of the neighbors we exchange routing information
- * with (peers up to DEFAULT_FISHEYE_DEPTH - 1 distance from us).
- */
-static struct GNUNET_CONTAINER_MultiHashMap *routing_neighbors;
-
-/**
  * Hashmap with all routes that we currently support; contains 
  * routing information for all peers up to distance DEFAULT_FISHEYE_DEPTH.
  */
@@ -619,20 +599,6 @@
 
 
 /**
- * Begin exchanging routing information with 'rn', updating
- * our respective neighbor table in the process.
- *
- * @param rn neighbor with whom we should exchange the information
- */
-static void
-exchange_routing_information (struct RoutingNeighbor *rn)
-{
-  GNUNET_break (0);
-  // FIXME
-}
-
-
-/**
  * Find a free slot for storing a 'route' in the 'consensi'
  * set at the given distance.
  *
@@ -657,70 +623,6 @@
 
 
 /**
- * Setup an entry in the 'routing neighbor' table and begin the
- * exchange with the new routing neighbor.  Note that a routing
- * neighbor can be a direct neighbor at the same time, in which case
- * the peer identity of 'target' and 'next_hop->peer' will be the same
- * (and the distance will be 1).
- *
- * If a routing neighbor already exists, ignore the update if
- * the distance is not smaller; otherwise if the distance
- * is smaller, replace the existing entry with the new route.
- *
- * @param next_hop first routing hop towards the routing neighbor
- * @param target peer identity of the routing neighbor
- * @param distance number of hops to the routing neighbor
- */
-static void
-create_routing_neighbor (struct DirectNeighbor *next_hop,
-                        const struct GNUNET_PeerIdentity *target,
-                        uint32_t distance)
-{
-  struct RoutingNeighbor *rn;
-  unsigned int i;
-
-  rn = GNUNET_CONTAINER_multihashmap_get (routing_neighbors, 
-                                         &target->hashPubKey);
-  if (NULL != rn)
-  {
-    /* update the entry, instead of creating a new one */
-    if (distance >= rn->route.target.distance)
-      return; /* ignore, distance is not better */
-    rn->route.next_hop = next_hop;
-    if (distance < rn->route.target.distance)
-    { 
-      /* move to alternative consensi slot */
-      consensi[rn->route.target.distance].targets[rn->route.set_offset] = NULL;
-      rn->route.target.distance = distance;
-      i = get_consensus_slot (distance);
-      rn->route.set_offset = i;
-      consensi[distance].targets[i] = &rn->route;      
-    }
-    if (DIRECT_NEIGHBOR_COST == distance)
-    {
-      /* we're now a direct neighbor, remove from set reachable via DV! */
-      send_disconnect_to_plugin (target);
-    }
-    return;
-  }
-  GNUNET_assert (distance < DEFAULT_FISHEYE_DEPTH - 1);
-  i = get_consensus_slot (distance);
-  rn = GNUNET_malloc (sizeof (struct RoutingNeighbor));
-  rn->route.next_hop = next_hop;
-  rn->route.target.peer = *target;
-  rn->route.target.distance = distance;
-  rn->route.set_offset = i;
-  consensi[distance].targets[i] = &rn->route;
-  exchange_routing_information (rn);
-  GNUNET_assert (GNUNET_YES ==
-                GNUNET_CONTAINER_multihashmap_put (direct_neighbors,
-                                                   &target->hashPubKey,
-                                                   rn,
-                                                   
GNUNET_CONTAINER_MULTIHASHMAPOPTION_UNIQUE_ONLY));
-}
-
-
-/**
  * Method called whenever a peer connects.
  *
  * @param cls closure
@@ -734,8 +636,9 @@
                      unsigned int atsi_count)
 {
   struct DirectNeighbor *neighbor;
-  struct RoutingNeighbor *rn;
+  struct Route *route;
   uint32_t distance;
+  unsigned int i;
 
   /* Check for connect to self message */
   if (0 == memcmp (&my_identity, peer, sizeof (struct GNUNET_PeerIdentity)))
@@ -757,7 +660,33 @@
                                                    &peer->hashPubKey,
                                                    neighbor,
                                                    
GNUNET_CONTAINER_MULTIHASHMAPOPTION_UNIQUE_ONLY));
-  create_routing_neighbor (neighbor, peer, DIRECT_NEIGHBOR_COST);
+
+  route = GNUNET_CONTAINER_multihashmap_get (all_routes, 
+                                            &peer->hashPubKey);
+  if (NULL == route)  
+  {
+    route->target.peer = *peer;
+    i = get_consensus_slot (DIRECT_NEIGHBOR_COST);
+    route->set_offset = i;
+    consensi[DIRECT_NEIGHBOR_COST].targets[i] = route;
+    GNUNET_assert (GNUNET_YES ==
+                  GNUNET_CONTAINER_multihashmap_put (all_routes,
+                                                     
&route->target.peer.hashPubKey,
+                                                     route,
+                                                     
GNUNET_CONTAINER_MULTIHASHMAPOPTION_UNIQUE_ONLY));
+  }
+  else
+  {
+    /* move to new consensi slot */
+    send_disconnect_to_plugin (peer);
+    consensi[route->target.distance].targets[route->set_offset] = NULL;
+    i = get_consensus_slot (DIRECT_NEIGHBOR_COST);
+    route->set_offset = i;
+    consensi[DIRECT_NEIGHBOR_COST].targets[i] = route;      
+  }
+  route->next_hop = neighbor;
+  route->target.distance = DIRECT_NEIGHBOR_COST;
+  // FIXME: begin exchange_routing_information!
 }
 
 
@@ -829,27 +758,62 @@
 
 
 /**
- * Multihashmap iterator for freeing routes that go via a particular
- * neighbor that disconnected and is thus no longer available.
+ * Multihashmap iterator for checking if a given route is
+ * (now) useful to this peer.
  *
- * @param cls the direct neighbor that is now unavailable
+ * @param cls the direct neighbor for the given route
  * @param key key value stored under
- * @param value a 'struct Route' that may or may not go via neighbor
+ * @param value a 'struct Target' that may or may not be useful
  *
  * @return GNUNET_YES to continue iteration, GNUNET_NO to stop
  */
 static int
-cull_routing_neighbors (void *cls, const struct GNUNET_HashCode * key, void 
*value)
+cull_routes (void *cls, const struct GNUNET_HashCode * key, void *value)
 {
   struct DirectNeighbor *neighbor = cls;
-  struct RoutingNeighbor *rn = value;
+  struct Target *target = value;
+  struct Route *cur;
+  
+  cur = GNUNET_CONTAINER_multihashmap_get (all_routes,
+                                          key);
+  if (NULL != cur)
+  {
+    if (cur->target.distance > target->distance)
+    {
+      /* FIXME: this 'target' is cheaper than the existing route;
+        switch route! */
+    }
+    return GNUNET_YES; /* got a route to this target already */
+  }
+  cur = GNUNET_malloc (sizeof (struct Route));
+  cur->next_hop = neighbor;
+  cur->target = *target;
+  cur->set_offset = get_consensus_slot (target->distance);
+  GNUNET_CONTAINER_multihashmap_put (all_routes,
+                                    key,
+                                    cur);
+  return GNUNET_YES;
+}
 
-  if (rn->route.next_hop != neighbor)
-    return GNUNET_YES; /* not affected */
 
-  /* FIXME: destroy routing neighbor! */
-  GNUNET_break (0);  
+/**
+ * Multihashmap iterator for finding routes that were previously
+ * "hidden" due to a better route (called after a disconnect event).
+ *
+ * @param cls NULL
+ * @param key peer identity of the given direct neighbor
+ * @param value a 'struct DirectNeighbor' to check for additional routes
+ * @return GNUNET_YES to continue iteration
+ */
+static int
+refresh_routes (void *cls, const struct GNUNET_HashCode * key, void *value)
+{
+  struct DirectNeighbor *neighbor = value;
 
+  if (NULL != neighbor->neighbor_table)
+    GNUNET_CONTAINER_multihashmap_iterate (neighbor->neighbor_table,
+                                          &check_possible_route,
+                                          neighbor);
   return GNUNET_YES;
 }
 
@@ -889,9 +853,6 @@
   GNUNET_CONTAINER_multihashmap_iterate (all_routes,
                                         &cull_routes,
                                          neighbor);
-  GNUNET_CONTAINER_multihashmap_iterate (routing_neighbors,
-                                        &cull_routing_neighbors,
-                                         neighbor);
   if (NULL != neighbor->cth)
   {
     GNUNET_CORE_notify_transmit_ready_cancel (neighbor->cth);
@@ -902,6 +863,9 @@
                                                       &peer->hashPubKey,
                                                       neighbor));
   GNUNET_free (neighbor);
+  GNUNET_CONTAINER_multihashmap_iterate (direct_neighbors,
+                                        &refresh_routes,
+                                         NULL);
 }
 
 
@@ -925,26 +889,6 @@
 
 
 /**
- * Multihashmap iterator for freeing routing neighbors. Should never be called.
- *
- * @param cls NULL
- * @param key key value stored under
- * @param value the distant neighbor to be freed
- *
- * @return GNUNET_YES to continue iteration, GNUNET_NO to stop
- */
-static int
-free_routing_neighbors (void *cls, const struct GNUNET_HashCode * key, void 
*value)
-{
-  struct RoutingNeighbor *router = value;
-
-  GNUNET_break (0); 
-  // FIXME: release resources
-  return GNUNET_YES;
-}
-
-
-/**
  * Multihashmap iterator for freeing direct neighbors. Should never be called.
  *
  * @param cls NULL
@@ -979,9 +923,6 @@
   GNUNET_CONTAINER_multihashmap_iterate (direct_neighbors,
                                          &free_direct_neighbors, NULL);
   GNUNET_CONTAINER_multihashmap_destroy (direct_neighbors);
-  GNUNET_CONTAINER_multihashmap_iterate (routing_neighbors,
-                                         &free_routing_neighbors, NULL);
-  GNUNET_CONTAINER_multihashmap_destroy (routing_neighbors);
   GNUNET_CONTAINER_multihashmap_iterate (all_routes,
                                          &free_route, NULL);
   GNUNET_CONTAINER_multihashmap_destroy (all_routes);
@@ -1072,7 +1013,6 @@
 
   cfg = c;
   direct_neighbors = GNUNET_CONTAINER_multihashmap_create (128, GNUNET_NO);
-  routing_neighbors = GNUNET_CONTAINER_multihashmap_create (128 * 128, 
GNUNET_NO);
   all_routes = GNUNET_CONTAINER_multihashmap_create (65536, GNUNET_NO);
   core_api = GNUNET_CORE_connect (cfg, NULL,
                                  &core_init,